Progress in Clean Energy, Volume 1

The goal to achieve a sustainable society that will endure over the long term is generally regarded as a positive evolutionary course. One of the challenges with this goal is developing a quantitative assessment of the sustainability of a system. Despite the different measures available in the literature, a standard and universally accepted index for assessing sustainability does not yet exist. Here, we develop a novel integrated sustainability index (ISI) for energy systems that considers critical multidimensional sustainability criteria. The originality of this new index is that it incorporates fundamental thermodynamic, economic, and environmental constraints to combine indicators from multiple dimensions into a single-score evaluation of sustainability. The index is therefore unique because it can assess sustainability relative to an ideal reference state instead of being limited to ranking systems via relative assessments. The ISI is applied to a stand-alone solar-PV-battery system designed to meet the needs of a small community in Southern Ontario. The ISI of the system ranges from 0.52 to 0.66, where one is considered to be a sustainable system. The weighting factors associated with critical economic and global environmental criteria have the greatest effect on the ISI. This index is expected to prove useful as a high-level, multi-criteria decision analysis tool for understanding and fostering sustainable energy systems, alone or in concert with other approaches.

Integrated energy production systems based on the renewable or fossil energy sources for poly-generation applications are inevitable in the near future for both environmental and sustainability concerns. Increasing the overall efficiency by combining system decreases the energy consumption and increases the system outputs such as electricity, heat, hot water, cooling, hydrogen, oxygen, and ext. Considering the global energy demands, the increase of efficiency of poly-generation systems will decrease emissions and therefore helps to protect the environment. Moreover, not only decreasing the emissions but also reducing the energy consumption is very important to achieve more sustainable systems, and it is again possible with integrated systems. In this chapter, thermodynamic assessment formulations and energy and exergy efficiency of a new poly-generation design which consists of biomass gasification, solid oxide fuel cell (SOFC), organic Rankine cycle (ORC), and double-effect absorption cooling and heating systems are given and analyzed in detail through energy, exergy, and sustainability approaches.

In this study, a Maisotsenko combustion turbine cycle (MCTC) with compressor inlet cooling system is proposed and studied through energy, exergy and exergoeconomic analysis methods. The present system consists of a Maisotsenko air cooler, a compressor, a turbine, a generator, a combustor, and a compressed air saturator. The results show that an exergy efficiency of 58.27 % is higher than the corresponding energy efficiency of 51.55 % for the MCTC system, due to the fact that the exergy content of the fuel fed into the combustion chamber is lower than its energy content. Also, the maximum exergy destruction rates occur in the compressor and turbine with the values of 166.964 kW and 150.864 kW, respectively. Furthermore, the exergoeconomic results indicate that the highest exergetic cost factor defined as the destruction in the component per cost is determined to be 0.013148 kW/$ for the turbine, while the Maisotsenko cycle air cooler has a minimum rate of 0.000006 kW/$. The better optimization of this component may be considered. It is concluded that Maisotsenko cycle systems can be effectively integrated to turbine cycle systems. Also, energy, exergy and exergoeconomic analyses give more useful information together about assessing the MCTC system and minimizing the thermodynamic inefficiencies.

Useful energy can be extracted from agricultural waste and residues instead of the uncontrolled burning that causes severe harm to the environment. Rice straw can be combusted in a fluidized bed producing useful heat with better control of emissions. One of the most promising alternatives is converting biomass into a more energy-dense fuel with a higher heating value through gasification. This study presents a one-dimensional model of atmospheric bubbling fluidized bed and investigates the effect of different operating parameters on the temperature profile and gas species concentrations through the fluidized bed in the gasification process through concentration and energy balance equations. The model is validated with data and measurements from the literature. The temperature profiles show a peak temperature value occurring early in the freeboard zone. Both the value and position of the peak occurrence are affected by the operation and fluidization condition.

In this paper, thermodynamic analysis of an integrated system with parabolic collector which produces a number of outputs, such as heating, cooling, hot water, and electricity, is investigated. This integrated system consists of four main subsystems: concentrating collector, energy storage, Rankine cycle, and double-effect absorption cooling and heating. The renewable energy-based system is operated in two modes, which are solar mode and storage mode. Exergy destruction ratios and rates, power or heat transfer rates, and energy and exergy efficiencies of the system components and whole system are carried out. From the results, energy and exergy efficiencies for solar mode are found as 51.32 and 46.75 %, whereas for storage mode these efficiencies are calculated as 47.44 % and 45.43 %, respectively. Additionally, parametric studies, including the thermodynamic performance of the system and its components, are conducted by the change in some design parameters, as variation of the ambient temperature changes from 0 to 30 °C.

This chapter deals with thermodynamic modeling, parametric analysis, and optimization of an integrated system to recover energy from pressure reduction station in city gate station (CGS). This chapter aims to fully cover the thermodynamic modeling of an integrated system consisting of a turbo expander, an organic Rankine cycle (ORC) and a proton exchange membrane (PEM) electrolyzer to produce and store hydrogen. The pressure of natural gas in transmission pipeline in Iran gas system is high which sometimes go beyond 7 MPa. This pressure needs to be reduced near the cities pipeline pressure to 1.7 MPa. This pressure reduction results in ample potential to recover energy to generate electricity. In the proposed integrated system in this chapter, a comprehensive parametric analysis including the effect of main parameters such as natural gas preheat temperature, the natural gas pressure inlet to turbo expander, the heater mass fuel flow rate, and high temperature of ORC on the system performance is investigated.

The results show that although the natural gas inlet pressure has a trivial effect on exergy efficiency of the ORC cycle, PEM electrolyzer, and turbo expander, it has a significant effect on turbo expander power output and hydrogen production rate. Besides, results indicate that increase in preheat temperature of natural gas from 130 to 165 °C has the favorable effect on the turbo expander power output and exergy destruction rate of ORC components. Also, it is concluded that an increase in preheat temperature leads to a decrease in hydrogen production from 15.9 to 14.8 kg/day due to decrease in ORC output electricity. In order to determine the optimum value of design parameters, an optimization method is applied. The genetic algorithm optimization results show there are acceptable values for five design parameters which guarantee the optimum performance of the novel proposed integrated system.

A detailed thermodynamic analysis of simple and regenerative cycles of adsorption refrigeration is presented. Two functions of the incoming and outgoing energy for the regenerative cycle using two isothermal adsorbers have been calculated in order to obtain the heated adsorber temperature at the end of heat recovery. Results are presented in terms of performances for the pair activated carbon AC-35 as adsorbent and methanol as adsorbate. These results demonstrated that the performance coefficient of double-bed adsorption refrigeration cycle increases with respect to the single-bed configuration. Several main factors affecting the performances of cycles are discussed according to the results of computer simulations.

This paper investigates the usage of municipality water supply system for cooling a residential building. The study in this paper proposes that by using municipality water supply system, it is possible to reduce the cost of space cooling for residential units. Additionally, this system would have a lower initial investment cost in comparison with the conventional ground source heat pumps where specially designed piping system placed a few meters beneath the ground allows the usage of earth’s stored heat. For a regular municipality water delivery system, the carried water circulates through kilometers of piping already located underground which allows the water to exchange heat with the earth. Thus, it is possible to replace conventional heat pump systems and use regular tap water as a coolant for a residential unit. In order to achieve cooling, pipes can be installed on the walls and the ceiling of a house. The tap water could be circulated within these pipes. The study represented here shows that 5.48 kW of building cooling load could be handled with only 50 W of pump power for water circulation through the pipes located inside the walls and the ceiling of a proposed typical house.

Today, the meat processing industry plays an important role in boosting the economy of the region of Alentejo, Portugal, which possesses a strong economic linkage to rural traditional activities. However, several problems have been detected relating to an efficient use of the energy in their productive processes, leading to excessive and unnecessary consumptions, increasing bills and therefore costs of final products, reducing company’s competitiveness and causing increased emissions of greenhouse gases to the atmosphere.

The aim of this study is to characterize energy consumption of the meat processing industry in Alentejo, to understand where excesses are being committed and at the same time to identify opportunities for improvement of energy performance in the productive process. For this purpose data were collected through a field survey within a sample of companies and the respective findings were statistically analysed. Subsequently a study of the technical–economic impact of a set of efficiency measures was evaluated to reduce energy consumption and cost.

Results obtained showed that it is in the refrigeration systems and heat boilers that it is possible to achieve the largest reductions in energy consumptions and energy over costs, which may go up to 7 % (savings on consumption) and 19 % (savings on cost) through the implementation of efficiency measures with a payback period of less than 11 years.

Oil sands extraction and upgrading consume a significant amount of water, energy, as well as hydrogen to produce synthetic crude oil (SCO) from bitumen. This study examines the energy and exergy analysis of water usage for oil sands during extraction and upgrading. Steam and water supply to these processes are investigated by using Aspen Plus simulation software with consideration of heat transfer. These systems and their modifications are simulated and analyzed thermodynamically. The assessment involves the examination of several different factors and comparisons. The analysis includes energy and exergy flows with the amount of destroyed exergy during the processes and operations. The results provide new insight for the design, optimization, and modification of oil sands and upgrading processes.

The specific objective of this study was to investigate regional spatiotemporal distributions and spatial correlations of energy and water consumption in open, semi-closed, and completely closed greenhouse systems in British Columbia. The findings showed that the energy and water consumptions were both spatially and system dependent. Latitude and longitude significantly predicted total energy and water consumptions. Semi-closed and open heat pump systems were the most energy conserving systems while closed system was the most water conserving. Semi-closed and closed systems at lower latitudes had more water consumptions compared to those at higher latitudes while open systems at higher latitudes had more compared to those at lower latitudes. Locations close to the southwest Pacific Coast had the lowest energy and water consumptions in all systems.

The specific objective of this study was to investigate regional spatiotemporal distributions and spatial correlations of energy and water consumption in open, semi-closed, and completely closed greenhouse systems in the Canadian Maritimes. The findings showed that the energy and water consumptions were both spatially and system dependent. Latitude, longitude, and altitude all significantly predicted total energy consumptions; however, none of these variables predicted water consumptions in the Canadian Maritimes. Semi-closed and open heat pump systems were the most energy conserving systems, while closed system was the most water conserving. Locations on or close to the south central Nova Scotia had the lowest energy consumptions in all systems, which is comparable to major greenhouse regions in southwestern British Columbia and Ontario. This study revealed potentially a new greenhouse region in the Canadian Maritimes, Nova Scotia, which currently does not have a significant greenhouse industry.

The specific objective of this study was to investigate regional spatiotemporal distributions and spatial correlations of energy and water consumption in open, semi-closed, and completely closed greenhouse systems in Ontario. The findings showed that the energy and water consumptions were both spatially and system dependent. Latitude and longitude both significantly predicted total energy and water consumptions. Altitude was significant in conventional and open heat pump systems’ energy consumptions. Semi-closed and open heat pump systems were the most energy conserving systems while closed system was the most water conserving. Semi-closed and closed systems at lower latitudes had more water consumptions. Open system had more water consumption at higher latitudes and longitudes compared to those at lower latitudes and longitudes, respectively. Locations in the southwest (a major greenhouse region in Ontario) had the lowest energy consumptions in all systems.

The specific objective of this study was to investigate regional spatiotemporal distributions and spatial correlations of energy and water consumption in open, semi-closed, and completely closed greenhouse systems in the Canadian Prairies. The findings showed that the energy and water consumptions were both spatially and system dependent. Both latitude and longitude significantly predicted total energy consumptions. Latitude significantly predicted water consumption in semi-closed and closed systems as well. Semi-closed system was the most energy conserving system, while closed system was the most water conserving. Locations at lower latitudes had higher water consumption due to increased amount of available solar radiation. Water consumptions in open systems at higher and lower latitudes approached to each other due to relatively increased transpiration rates at higher latitudes as the vapor pressure deficit became larger due to colder and drier outside air. Locations in the southwestern Prairies (Alberta, and partly Saskatchewan) had the lowest energy consumptions in all systems.

The specific objective of this study was to investigate regional spatiotemporal distributions and spatial correlations of energy and water consumption in open, semi-closed, and completely closed greenhouse systems in Quebec and Labrador. The findings showed that the energy and water consumptions were both spatially and system dependent. Latitude, and depending on the system longitude as well, significantly predicted total energy consumptions. Semi-closed and open heat pump systems were the most energy conserving systems while closed system was the most water conserving. Semi-closed and closed systems at lower latitudes had more water consumptions compared to those at higher latitudes. Water consumptions in open systems at higher latitudes approached to or were sometimes higher than those at lower latitudes as the vapor pressure deficit became larger due to cooler outside air. Southern Quebec had the lowest energy consumptions in all systems.

This work presents an experimental investigation on a reciprocating active magnetic regenerator (AMR) refrigerator-demonstrator operating near room temperature. La(Fe, Co)

13−

x

Si

x

is used as a refrigerant material in the form of multilayer and water as heat transfer fluid to release and absorb heat at the hot and cold sources, respectively. Experimental tests using the multilayer regenerator with an applied magnetic field of 1.45 T have produced a temperature span of 15.6 K, without cooling load. The effects of the following cycle parameters, namely, utilisations, frequencies and mass flow rates, on the AMR cycle performance are presented and discussed. A parametric study was conducted on the behaviour of the temperature span to define the optimum demonstrator parameters to improve performance and validate the concept of multilayer and provide useful data for magnetic refrigerator design.

A modeling study is conducted to evaluate the heat transfer capabilities of novel refrigerant clathrate-based phase change materials with salts and nanoparticles as additives. The formation of refrigerant clathrates is studied for both active and passive cooling applications. In this regard, the refrigerants, e.g., R134a, R141b, and R32 clathrates are studied at different refrigerant mass fractions since the solubility of refrigerants, in water, change with change in temperature. The sodium chloride and magnesium nitrate hexahydrate are used as salt additives. The nanoparticles of pure aluminum, copper, and graphene are also studied to investigate the improvement in their thermal properties. Some empirical correlations are used to predict the thermal conductivities of refrigerant clathrates and the improvement with the addition of additives. The results show that an increase in refrigerant mass fraction lowers the thermal conductivity of the refrigerant clathrate but not extensively. The addition of salts results in a minor improvement in thermal conductivity. The inclusion of nanoparticles significantly improved the thermal conductivity of the phase change material. It is also obtained that adding the nanoparticles improves the thermal conductivity more than the salts. The specific heat capacity, however, was not generally improved by the nanoparticles as it depended on the additive used.

Drinking water availability is one of the emerging challenges of the twenty-first century. Different technologies are investigated as possible sources of water for the arid regions. Atmospheric water vapor processing is a developing approach whose aim is to cool air to condensate the water present in the atmospheric moisture. Air dehumidification allows obtaining pure drinking water for geographical regions far from sea, rivers, and lakes.

This chapter presents the optimization of a refrigeration system for drinking water production through atmospheric air dehumidification. The system uses a fan to force the air through a heat exchanger, in which it is cooled. The water vapor condensates on the cooled heat exchanger surfaces and it is collected by gravity in a tank.

The system’s aim is to condensate the maximum water quantity achievable for every atmospheric air condition, represented by temperature, humidity, and pressure. Thus, a mathematical model is defined to determine the optimal atmospheric air flow that maximizes the condensed water production for every atmospheric air condition. Furthermore, to consider the atmospheric condition hourly profiles of the refrigeration system installation site, three air flow control strategies are proposed: hourly, monthly, and yearly. An experimental campaign is set up to validate the model. Experimental test results show that it accurately predicts the drinking water production (gap between −5.6 and +4.1 %). Finally, the case study of a refrigeration system installed in Dubai, United Arab Emirates, is presented to assess and compare the proposed three air flow control strategies.

In this chapter, the short-term forecasting of the global solar irradiation using the fuzzy modeling technique is proposed. The multi-input multi-output (MIMO) fuzzy models are used to predict the next 24 h ahead based on the mean values of the daily solar irradiation and the daily air temperature. The measured meteorological data of Tamanrasset City, Algeria (altitude, 1,362 m; latitude, 22°48 N; longitude, 05°26 E) is used, where the 2 years (2007–2008) are used for modeling and the year 2009 is used to validate the developed model. Several models are presented to test the feasibility and the performance of the fuzzy modeling technique for forecasting hourly solar irradiation in the MIMO strategy. Results obtained throughout this chapter show that the fuzzy modeling technique is suitable for a short-time forecasting of the solar irradiation.

Solar energy applications need reliable forecasting of solar irradiance. In this study, we present an assessment of a short-term global horizontal irradiance forecasting system based on Advanced Research Weather Research and Forecasting (WRF-ARW) meteorological model and neural networks as a post-processing method to improve the skill of the system in a highly favorable location for the utilization of solar power in Turkey.

The WRF model was used to produce 1 month of 3 days ahead solar irradiance forecasts covering Southeastern Anatolia of Turkey with a horizontal resolution of 4 km.

Single-input single-output (SISO) and multi-input single-output (MISO) artificial neural networks (ANN) were used.

Furthermore, the overall results of the forecasting system were evaluated by means of statistical indicators: mean bias error, relative mean bias error, root mean square error, and relative root mean square error. The MISO ANN gives better results than the SISO ANN in terms of improving the model predictions, provided by WRF-ARW simulations for August 2011.

This paper focuses on the CitInES (City and Industry Energy System) project industrial use case, Tüpraş. The industrial use case includes plant modeling, historical replay, optimization, operation policy, and field testing. Reliable modeling was ensured by taking advantage of actual historical data. Missing or corrupted data were handled by data reconciliation. Optimization was carried out on historical operational data to develop optimized strategies which respect numerous actual technical constraints (design and safety constraints, efficiency curves, start-up costs). A guideline was created for operational management and another for electricity market bidding. During experimentation, the tool developed within the CitInES project handled complex utility systems and provided strategies for operating a power plant, enabled bidding on the Turkish electricity market, and answered feasibility studies for investment projects. The new production and bidding guidelines designed with the software reduced utility costs by 7 % without any new investment when compared to previous years.

This chapter presents the use of neural network for predicting energy consumption in buildings and their expenditure. Application of artificial intelligence by the use of neural networks to predict the energy consumption for heating rehabilitated buildings is underscored by the need to develop a generic model that can be used for prediction of the consumption of the energy in buildings. The model presented for the prediction of the energy consumption of natural gas has been developed on the basis of data obtained for the winter period. Alternatively, a comparative economic study was conducted. An average error of the training phase for the model was 2.4 %, while the test phase error was 3.2 %. This indicates that the neural network model is presented successfully to predict the energy consumption by using natural gas as clean energy for heating buildings

In this chapter, the prediction of the daily global solar irradiation of the great Maghreb region using the complex-valued wavelet neural network (CVWNN) is presented. Both multi-input single output (MISO) and multi-input multi-output (MIMO) strategies are considered. The meteorological data of the capitals of the great Maghreb, which are Tripoli (Libya), Tunis (Tunisia), Algiers (Algeria), Rabat (Morocco), El Aaiun (Western Sahara), and Nouakchott (Mauritania), are used like samples from each country. To test the applicability and the feasibility of the CWNN to predict the daily global irradiation for the great Maghreb case, several models are presented. Results obtained throughout this chapter show that the CWN technique is suitable for prediction of the daily solar irradiation of the great Maghreb region.

An artificial neural network (ANN) is used to model the static adsorption of copper, chromium, lead, and nickel by natural wastes, which are respectively charred cereal waste, Mediterranean biomass (Posidonia oceanica (L) DELILE), activated carbon as well as olive kernel and pulp. This intelligent model is used to predict and estimate the amount of adsorbed metal per mass unit of adsorbent or the yield percentage of the adsorption. The results obtained using multilayer neural network shows its effectiveness in predicting the experimental results. The relative error is 0.2 mg/g for charred cereal waste/Copper, Biomass/Chromium, and 1.9 % for the combinations activated carbon/Lead, olive kernel/Nickel, and olive pulp/Nickel, respectively. Furthermore, the same artificial neural network is exploited to predict the effect of some operating parameters (pH, temperature, initial metal concentration, contact time, agitation speed, ionic strength, and adsorbent weight) that affect the static adsorption of these metals by several types of adsorbents.

In this work, we numerically study the effects of heat generating fins in an annular pipe on the three-dimensional conjugate heat transfer: conduction in the solid and mixed convection in the working fluid. The horizontal annular pipe is equipped by longitudinal attached fins on internal surface of outer cylinder. The external pipe and the fins are heated by an electrical current passing through their small thickness. The number of longitudinal fins studied is: 2 vertical, 4 and 8 fins. The convection in the fluid domain is conjugated to thermal conduction in the pipes and fins solid thickness. The physical properties of the fluid are thermal dependent. The heat losses from the external pipe surface to the surrounding ambient are considered. The model equations of continuity, momenta, and energy are numerically solved by a finite volume method with a second-order spatiotemporal discretization. The obtained results showed that the axial Nusselt number increases with the increasing of number and height of fins. The participation of fins located in the lower part of the tube on the improvement of heat transfer is higher than the participation of the upper fins.

In this chapter, a new methodology for heat exchanger networks synthesis, extending traditional pinch technology to include exergy-destruction cost, is described and employed for practical applications. In the proposed approach, the cost rate of exergy destruction substitutes the utility cost in a trade-off between the operating and capital costs in the conventional pinch analysis to determine the optimum minimum approach temperature, Δ

T

min

, in the energy assessment of heat exchanger networks (HENs). It is demonstrated that the balanced composite curves can be used directly in the calculation of the exergy destruction, heat recovery, and heat-transfer area for a specified minimum approach temperature. Moreover, it is showed that the grand composite curve can be utilized for determination of the optimal external utility allocation. The inclusion of thermal exergy destruction into pinch analysis decreases the optimum value of network Δ

T

min

, due to increase in the system operating costs by considering both the external utility requirements and internal exergy destruction. The results of this assessment provide a better and more realistic utilization of external utilities considers the required capital investment. Two case studies are presented to show how to apply the proposed methodology effectively and practically. Case studies are analyzed using Aspen energy analyzer software.

In fuel cell systems, the heat exchanger is one of the most important pieces of equipment. and needs to be of robust design and optimization. This study is about the serpentine type heat exchanger with a rectangular shell. It has a tube bundle with a lot of pass and is operated for two-phase service. It is essential to estimate the exact velocity value in order to predict the effect of flow-induced vibration and heat transfer characteristics. It is difficult to estimate the velocity for special heat exchangers due to the variable temperature gradient on each tube. This chapter presents the methodology for the velocity prediction. By comparison with real hot test and the results of analysis, results, the reliability of the 1D calculation could be verified. Also this chapter presents the detail values that are the scalar values for the heat exchanger. Then the velocity profile can be obtained as a vector value on each tubes as well as their physical properties.

In this study, polyurethane nanocapsules containing phase change material were synthesized by interfacial polycondensation polymerization method. Toluene-2,4-diisocyanate (TDI) and diethylenetriamine (DETA) were chosen as monomers.

n

-Nonadecane was employed as a core material. The properties of nanocapsules were characterized by DSC, FT-IR, and SEM. The results show that the nanocapsules were synthesized successfully and that the phase change temperature was about 29.6 °C, and the latent heat of fusion was about 82 Jg

−1

. The particle size was found to range from 100 to 340 nm.

Recently, the means of improvement of heat transfer has been rapidly studied. One of the methods that enhance the heat transfer is by changing the heat exchanging fluids. The poor heat transfer coefficient of common fluids compared to the most solids becomes the primary obstacle to design high compactness and effectiveness of heat exchanger. The primary objective of this chapter is to conduct the study of the heat transfer between the water and nanofluid. Both of the fluids were flowed in the horizontal counter flow heat exchanger under the turbulent flow condition. The flow velocity of the fluids varied with Re between 4,000 and 18,000. Literature review states that the heat transfer coefficient of nanofluid is higher than the water by about 6–11 %. Heat transfer to the nanofluid and water is investigated using a computer fluid dynamics software. Ten percent heat transfer augmentation is observed utilizing nanofluid as heat exchanging fluid compared to water. The results also showed the enhancement of the Reynolds number increases the heat transfer to the nanofluid studied in this investigation.

Industrial waste has been considered as an option in the initiative to promote green and sustainable construction. Oil palm shell (OPS) is one of the industrial wastes produced from the processing of palm oil and its ability to be used as a lightweight aggregate in concrete mixes has been tested. OPS has a high porosity content, which means that it is a good heat insulation material in concrete. This study focuses on the OPS volume fraction in concrete and its effects on the thermal insulation concrete. The volume fractions used are 30, 32, 34, 36, and 38 % from concrete density. Density decreases with the increase of volume fraction. The highest reduction from air dry to oven density is 13 %, which is obtained from a volume fraction of 34 % OPS. The volume fraction affected compressive strength and thermal conductivity. All mixes achieved for the requirement for load-bearing strength based on compressive strength were obtained. The highest strength was 22 Mpa by volume fraction, 30 % used. Volume fractions used are within the range of the semi-structure which has the same capacity as thermal insulation materials, below 0.75 W/m K (according to RILEM requirements) except for the volume fraction, 30 %. The thermal properties increased according to the increase in density except for the specific heat result, and they have a strong relationship within the thermal conductivity and compressive strength results. Thus the OPS lightweight concrete (OPSLC) capacity as a heat insulation material is proven and it can reduce energy use in buildings.

The aim of the present study is to examine the Dufour influence and Soret effects on entropy generation in convective heat and mass transfer for the case of a binary gas mixture with a single diffusive species in a square cavity. We numerically investigate the thermosolutal convection in a square cavity, where a binary mixture of incompressible fluid is confined under the conditions of both thermal and solutal gradients. Furthermore, we analyze the effect of Dufour and Soret on entropy generation. We find that, according to Grashof number values, the entropy generation could be mainly due to heat transfer or to fluid friction irreversibility and that the Soret and Dufour effects have great impact on the production of entropy.

The aim of this work is to analyze the three-dimensional temperature fields in a planar solid oxide fuel cell (SOFC) single cell with different geometric configurations: supported anode, electrolyte, or cathode (SA, SE, and SC). The temperature distribution is determined by taking into account only the largest heat source due to ohmic overpotential loss resulting from the Joule effect. The temperature values are obtained using a program in FORTRAN language which is based on the method of three-dimensional finite difference. The three-dimensional numerical study result analysis shows the localization of the highest temperature value at the SOFC component’s specific area: cathode (C), electrolyte (E), anode (A), and interconnector.

The purpose of this work is to present a two-dimensional transient model of the gas flow in the fuel cell (PEMFC). The model includes various conservation equations such movement and energy equations. The governing equations were resolved by the finite volume method. The objective of this work is to know the maximum temperature and its location in PEMFC and to determine the performance conditions of the fuel cell under the current density and velocity inlet effect. The polarization curve obtained numerically is compared with much numerical work. The numerical results show the regime flow effect and the nature of porous middle on the gas distribution in the membrane electrode assembly (MEA).

This work focuses on modeling and simulation of the structure based on GaAsNBi/GaAs for photovoltaic application. Indeed, the incorporation of a small composition nitrogen N <5 % and bismuth Bi <12 % induces the splitting of the conduction band into two bands and the valence band, respectively. Under the effect of this splitting, there is reduction of the bandgap which is very interesting for increasing the absorption. For

x

 = 1 % and

y

 = 10 %, the bandgap energy is

E

g

 = 0.68 eV and the absorption coefficient equal to 1.15 × 10

6

cm

−1

with a yield around 20 %. The use of structures based on new materials allows us to improve the performance of the optical conversion.

This study presents a mathematical model for simulating the transient processes of cylindrical solar water heater. The model simulates the solar collector system including the glass cover, the copper coil, and the working fluid. The equations are based on the energy balance for each part of the solar system; the physical parameters are identified promptly to make the model accessible; constant thermophysical properties are used. The differential equations were solved using the fourth-order Runge–Kutta method. A computer code has been conceived in this study using the Fortran 6.6 platform. Numerical simulations have been carried out to explore the temperature profiles of each part of the present configuration, in order to estimate its efficiency in two different situations: collector with and without gap layer. We have analyzed the effect of the instationary term in this context. A quasi-stationary state shifted due to air gap and temperature variation of the working fluid and the absorber. The results have been confronted to experimental comparison measurements available in the open literature.

In this chapter, the results of three-dimensional computational fluid dynamics (CFD) finite volume simulations of airflow around a commercial Vestas V80 Horizontal Axis Wind Turbine (HAWT), with a rated output power of 2 MW, are presented. The grid used in the simulations consists of two main parts, i.e., unstructured mesh rotating with blades and structured hexahedral stationary one for the external domain. Several cases with different free stream velocities (and different tip speed ratios and mean pitch angles) are studied, employing four different turbulence models:

k

−

ω

$$ k-\omega $$

SST,

υ

¯

2

−

f

$$ {\overline{\upsilon}}^2-f $$

,

k

−

ε

$$ k-\varepsilon $$

RNG and Spalart–Allmaras one-equation, in order to examine their ability to predict the output generated power of HAWTs. The investigation outcomes are compared with each other and existing experimental result given in previous studies. It is shown that the numerical results are in acceptable agreement with experiments. Regarding assumptions during simulations, more sensible output power values are obtained through

k

−

ε

$$ k-\varepsilon $$

RNG and

υ

¯

2

−

f

$$ {\overline{\upsilon}}^2-f $$

models. In addition, maximum value of power coefficient occurs at more accurate associated wind speed using

υ

¯

2

−

f

$$ {\overline{\upsilon}}^2-f $$

model. The simulations provide useful guidelines to design more efficient large commercial wind turbines.

Zn

1−

x

Mg

x

O (ZMO) films were prepared by the ultrasonic spray pyrolysis technique and effects of doping on structural, optical, electrical, and surface properties were examined. The film structures were studied by X-ray diffraction. X-ray diffraction patterns of the films showed that the ZMO films exhibited hexagonal wurtzite crystal structure with a preferred orientation along (0 0 2) direction. Texture coefficient, grain size values, and lattice constants were calculated. The optical properties like transmission, reflection, and absorption were investigated with UV–Vis spectrophotometer. The optical measurements reveal a shift in absorption edge and optical band gap of ZMO films changed with Mg content. Optical parameters (refractive index, extinction coefficient) and thicknesses of the films were investigated by spectroscopic ellipsometry (SE). Surface and electrical properties of the films were studied using atomic force microscopy and four-probe technique, respectively. After all investigations, it is concluded that the ZMO thin films can be used in photovoltaic solar cells as window materials and cell efficiencies can be increased using different content rates.

The Thiele–Winter reaction is of interest for synthesis of triacetoxyaromatic precursors of hydroquinones.

Solid acids such as heteropolyacids and activated zeolites have an efficient catalyst in acetoxylation reaction of quinones without the use of organic solvent at room temperature. Hydroquinones and substituted hydroquinones was easily oxidized at room temperature in quinones by using (Pc[Co]/K10) and air (1 atm). We have also tested this type of reaction in naphthoquinone series. Many naphthoquinones are natural products with interesting biological properties. The catalytic system (Pc[Co]/K10) in the presence of pure oxygen easily oxidizes the 1,5-dihydroxynaphthalene in Juglone (yield 87 %).

Fossil fuel combustion is the major source of CO

2

emissions. There are a number of techniques that can be used to separate CO

2

from the rest of the flue gas. The main disadvantage of these techniques is the large amount of energy that is required for the separation, which means a relative reduction of the overall efficiency of a power plant. Chemical looping combustion (CLC) is a new developing clean-combustion technology that has the advantage of inherent CO

2

separation ability. Thus, storage-ready, concentrated CO

2

can be obtained without the use of above-mentioned energy-intensive separation operations. This process involves two separate reactors, i.e., an air and a fuel reactor, and an oxygen carrier material which circulates between the reactors in order to extract and transport oxygen from air to fuel for many cycles. It is essential for oxygen carrier to be reactive, cheap to prepare, and durable over many cycles of reduction and oxidation at high reaction temperatures. Because of its good thermodynamical properties, physical strength, low cost, and low toxicity, iron oxide is a good candidate to be an oxygen carrier in CLC. This study will present a brief summary of developments obtained via CLC processes utilizing iron oxides as oxygen carrier.

In this investigation, the catalytic activity of palladium nanoparticles (PdNPs)-modified glassy carbon (GC) (simply noted as PdNPs/GC) electrodes towards the formic acid electro-oxidation (FAO) was investigated. The deposition of PdNPs on the GC substrate was carried out by a potentiostatic technique at different potentials and the corresponding influence on the particles size and crystal structure of PdNPs as well as the catalytic activity towards FAO was studied. Scanning electron microscopy (SEM) demonstrated the deposition of PdNPs in spherical shapes and the average particle size of PdNPs deposited at a potential of 0 V vs. Ag/AgCl/KCl(sat.) was the smallest (ca. 8 nm) in comparison to other cases, where the deposition proceeded at higher potentials. The electrochemical measurements agreed consistently with this, where the highest surface area of PdNPs was calculated similarly for the deposition carried out at 0 V vs. Ag/AgCl/KCl(sat.). Interestingly, the X-ray diffraction (XRD) analysis revealed a similar dependency of the PdNPs crystal structure on their particle size and distribution. The deposition of PdNPs at 0 V vs. Ag/AgCl/KCl(sat.) seemed exhibiting the best crystallinity. From the electrocatalytic point of view, the activity of the PdNPs/GC electrode towards FAO decreased with the deposition potential of PdNPs, which influenced consequently the particle size, shape, and/or crystallographic orientation of PdNPs.

In this work, production of ammonium borane (NH

3

BH

3

, abbreviated as AB) was studied. In synthesis works, the effect of reaction temperature and reactive inlet material concentrations on the conversion into AB were examined. Synthesis of ammonium borane was obtained from the reaction of NaBH

4

and (NH

4

)

2

SO

4

in THF. As a result of parametrical experiments, it has been determined that product conversion yield is increased from 95.3 to 98.2 % and reaction period is decreased by up to 2 h and product purity value is increased up to 100 % when reaction temperature is increased from 25 to 50 °C. It has been determined that when increased amount of reactive materials is compared with stoichiometric amounts, product conversion increased but limiting agent in the reaction is determined to be NaBH

4.

According to FTIR, XRD, and

11

B NMR analyses results, AB may be synthesized up to purity phase.

The present study proposes a novel promising binary catalyst for formic acid electro-oxidation (FAO); the main anodic reaction in direct formic acid fuel cells (DFAFCs). The catalyst is basically composed of two metal oxides of nickel and cobalt nanostructures (i.e., NiOx and CoOx) assembled onto a platinum nanoparticles (PtNPs)−modified glassy carbon (Pt/GC) electrode. Actually, FAO proceeds at bare Pt surfaces in two parallel routes; one of them is desirable (called direct or hydrogenation) and occurred at a low potential domain (

I

p

d

). While, the other (undesirable) involves the dehydration of formic acid (FA) at low potential domain to produce a poisoning intermediate (CO), which next be oxidized (indirect,

I

p

ind

) at a higher potential domain after the platinum surface becomes hydroxylated. Unfortunately, the peak current ratio (

I

p

d

/

I

p

ind

) of the two oxidation routes, which monitors the degree of the catalytic enhancement and the poisoning level, stands for bare Pt surfaces at a low value (less than 0.2). Interestingly, this ratio increased significantly as a result of the further modification of the Pt/GC electrode with NiOx

I

p

d

/

I

p

i

n

d

=

3

$$ \left({I}_{\mathrm{p}}^{\mathrm{d}}/{I}_{\mathrm{p}}^{\mathrm{ind}}=3\right) $$

, CoOx

I

p

d

/

I

p

i

n

d

=

4

$$ \left({I}_{\mathrm{p}}^{\mathrm{d}}/{I}_{\mathrm{p}}^{\mathrm{ind}}=4\right) $$

and a binary mixture of both

I

p

d

/

I

p

i

n

d

=

15

$$ \left({I}_{\mathrm{p}}^{\mathrm{d}}/{I}_{\mathrm{p}}^{\mathrm{ind}}=15\right) $$

. This highlights the essential role of these in promoting the direct FAO, presumably via a mediation process that ultimately improved the oxidation kinetics or through a catalytic enhancement for the oxidation of the poisoning CO at the low potential domain of the direct FAO. The effect of the deposition order of NiOx and CoOx on the catalytic activity was addressed and fount influencing. The addition of CoOx to the catalyst was really important, particularly in improving the catalytic stability of the catalyst towards a long-term continuous electrolysis experiment, which actually imitates the real industrial applications.

The current study presents a comparison for the electro-oxidation of formic acid (FA), glucose (GL), and methanol (ME) at nickel oxide nanoparticles (NiOx) modified electrodes. The modification with NiOx was pursed onto a bare glassy carbon (GC) and Pt-modified (Pt/GC) electrodes electrochemically, and the catalytic activity was measured in 0.3 M NaOH. Cyclic voltammetry (CV), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) are all used to provide a concrete characterization of the prepared electrodes. A catalytic enhancement of GL oxidation (GLO) and ME oxidation (MEO) was observed at the NiOx-modified GC (NiOx/GC) electrode, while the same electrode did not show any activity towards FA oxidation (FAO), revealing that FAO is substrate dependent. On the other hand, assembling NiOx onto the Pt/GC electrode assisted in improving the catalytic activity of all reactions (GLO, MEO, and FAO). The catalytic enhancement observed at the NiOx/Pt/GC electrode for GLO, MEO, and FAO was not only confined in the large increase of the oxidation current but also in a negative shift in the onset potential of the oxidation reaction. We believe NiOx could successfully play an essential role in this catalytic enhancement, presumably via participation in these reactions in a way facilitating the charge transfer or providing the oxygen atmosphere necessary for promoting an oxidative removal for unwanted poisoning species.

The effect of free fatty acids (FFAs) on the hydrodesulfurization (HDS) reaction of an atmospheric heavy gas oil over a commercial CoMo/γ-Al

2

O

3

catalyst was studied. Co-hydroprocessing of all liquid feed mixtures was carried out in a trickle-bed bench-scale three-phase stainless steel reactor at typical HDS conditions (310–350 °C reaction temperature and 33 bar reaction pressure). FFA content in the liquid feed varied from 0 to 20 % wt. Measurements concerning the final sulfur concentration, saponification number and acidity number of the final liquid product, the overall hydrogen consumption (HCON) for the liquid feed, and the composition of the gaseous phase after the hydrotreatment were obtained. The effect of the vegetable oil molecules on the HDS of gas oil was evaluated. Saponification and acidity number analysis showed full conversion (hydrodeoxygenation, HDO) of the heavy oxygenated molecules at all applied conditions. From the gaseous phase analysis, the products from the HDO of the carboxylic acids were determined. During the experimental tests, catalyst’s activity was measured and deactivation was found to be negligible.

Direct seeding is an important element of conservation agriculture; it contributes to environmental conservation and to sustainable agricultural production. Conservation agriculture increases carbon concentrations in the topsoil. It can also reduce the amount of fossil fuel consumed in intensive tillage and by other farm operations, and thus decrease the rate of CO

2

build-up in the atmosphere. Today, the global area of no-till farming is more than 100 million hectares. Setif high plains (north east of Algeria) is characterized by a semi arid climate with a long-term average annual precipitation ranging between 300 and 400 mm, the dry-farming system is commonly used, it is based on cereal/sheep production, the straw is used as main feed for livestock. In this region, direct seeding of cereals has recently been adopted, there is almost 9 years. The objective of this study was to quantify the carbon sequestered in the field by direct seeding of wheat. The experiment was conducted at the Setif ITGC experimental site during the 2010/2011 cropping season. The results indicate that dry straw left by the durum wheat varieties varies between 343 and 537 g/m

2

. It varies between 251 and 643 g/m

2

for bread wheat genotypes. Thus, the average amount of carbon sequestered each year is 260 gC/m

2

and 257 gC/m

2

successively for durum and bread wheat where the genotypes MBB and WAHA have high values of GY and C for durum wheat and RMADA have high values of GY and C for bread wheat. The direct seeding of wheat, relatively to conventional till, can reduce the use of fuel by 50–70 %, machinery requirements by 60 %, resulting in a decrease in production costs. Thus, a combination of the economic and environmental benefits through reduced labor requirements, time savings, reduced machinery and fuel savings, direct seeding has universal appeal. Indirect measures of social benefits as society enjoys a better quality of life from environmental quality enhancement will be difficult to quantify. Conservation agriculture, working in harmony with nature, enables the protection of nonrenewable natural resources and their preservation for future generations can be beneficial for feeding and greening the world.

Sewage sludge, which was collected from drying beds of the municipal wastewater treatment station in Algeria, was used to eliminate cationic dye (Rhodamine B) from aqueous solution. Sludge was chemically treated by different reagents and at different conditions in order to optimize the best conditions giving a maximum sorption of dye. Sulfuric acid at 0.1 mol/L was the efficient reagent to activated sewage sludge. The effect of ratio and temperature impregnation was evaluated; the results show that the impregnation ratio which gives a good coverage of the sorbent surface by acids is 25 at ambient temperature.

Ru/Al

2

O

3

-coated FeCralloy monolith catalyst was applied for the preferential CO oxidation (PrOx) to reduce CO concentration less than 10 ppm in reforming process. FeCralloy monolith was pre-calcined at 900 °C after electrochemical surface treatment which results in the formation of uniform Al

2

O

3

layer on the metal substrate. Pre-calcined monolith was coated with 10 wt% Al

2

O

3

sol and followed by 1.2 wt% Ru/Al

2

O

3

catalyst washcoating. The highly dispersed 1.2 wt% Ru/Al

2

O

3

catalyst was prepared by the deposition-precipitation method using 5 wt% NaOH solution as a precipitant. The characterization as to surface area, metal dispersion, and reduction temperature of catalysts were analyzed by BET, CO-chemisorption and H

2

-TPR. PrOx test was performed with GHSV of 5,000–30,000 h

−1

at 100–200 °C. The

λ

(2[O

2

]/[CO]) was adjusted between 1 and 2 and the effect of H

2

O and CO

2

was examined at

λ

 = 2. As a result, the metal dispersion of Ru coated on the FeCralloy monolith is higher than that of commercial pellet catalyst with the shape of sphere. The monolith catalyst shows higher CO conversion and CO

2

selectivity than the commercial catalyst due to the enhancement of thermal conductivity and the maximization of available Ru active site on the metal substrate. In addition, monolith catalyst has a superior tolerance to H

2

O and CO

2

. From this study, it is found that the Ru/Al

2

O

3

-coated monolith catalyst shows robust catalytic activity with 100 % CO conversion and 50 % CO

2

selectivity under 0.61 % CO, 0.61 % O

2

, 59 % H

2

, 19 % H

2

O, 16 % CO

2

, N

2

balance at GHSV = 5,000 h

−1

from 100 to 160 °C in PrOx.

The present study concerns the test of natural adsorbent obtained from a local cereal by-product as adsorbent for the removal of heavy metals such as Cu, Zn, and Cd ions from aqueous solutions. The solid support was used after calcinations at a temperature of 600 °C in exclusion of the air. The study was an opportunity to investigate the adsorption kinetics where equilibrium was reached after 30 min for the three metallic pollutants. The kinetic was of pseudo-second-order and controlled by intra-particle diffusion phenomenon. The isotherm of adsorption was also examined and showed a type C from Langmuir classification. The effect of important parameters such as the initial concentration and the contact time was also considered. The results showed a high retention capacity of the cereal by-product adsorbent, where yield values exceeding 90 % was reached for an initial concentration of 10 mg/L, at 20 °C, a mean size diameter of 0.1 mm, a mixing velocity of 600 rpm, a solid–liquid ratio of 10 g/L, a pH between 3 and 6, and a contact time of 2 h.

This chapter discusses response surface methodology (RSM) as an efficient approach for predictive model building and optimization of chromium adsorption on developed activated carbon. In this work, the application of RSM is presented for optimizing the removal of Cr (VI) ions from aqua solutions using activated carbon as adsorbent. All experiments were performed according to statistical designs in order to develop the predictive regression models used for optimization. The optimization of adsorption of chromium on activated carbon was carried out to ensure high adsorption efficiency at low adsorbent dose and high initial concentration of Cr (VI). While the goal of adsorption of chromium optimization was to improve adsorption conditions in batch process, i.e., to minimize the adsorbent dose and to increase the initial concentration of Cr (VI). In the adsorption experiments, a laboratory developed date stones activated carbon made of chemical activation (phosphoric acid) was used. A 2

4

full factorial central composite design experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value and satisfactory prediction second-order regression model was derived. Maximum chromium removal efficiency was predicted and experimentally validated.

Biochar has been acknowledged for its unique property which makes it potential candidates as adsorbent for carbon dioxide (CO

2

) in the flue gas system. In this study, the properties of raw coconut shell biochar (CSB) and amine treated coconut shell biochar (ACSB) are being compared. Physiochemical characterization has been performed to characterize the biochar properties. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to evaluate the functional groups and surface morphology of the biochar. Thermogravimetric analyzer (TGA) was used to discover the thermal properties, reactivity during adsorption. During the adsorption study, it was observed that amine treated coconut shell gasified at 800 °C gave the highest adsorption of 35.57 mg CO

2

/g sorbent at temperature of 30 °C. Nitrogen functionalities and the basicity of samples increased after the amine treatment and is said to assist the adsorption capacity.

Two families of Ni/TiO

2

catalysts were prepared for use in the steam reforming of ethanol. The catalytic performances, in terms of both H

2

productivity and stability towards coking and sintering, were related to the physico-chemical properties of the catalysts.

The samples were prepared either by synthesis of the support by precipitation and subsequent impregnation with the active phase, or by direct synthesis through Flame Pyrolysis. Many techniques have been used to assess the physico-chemical properties of both the fresh and spent catalysts. The samples showed different textural, structural and morphological properties, as well as different reducibility and thermal resistance, depending on the preparation method and support.

The performance of the titania-supported catalysts were found very dependent on the preparation procedure, and we may conclude that operation at 625 °C can be satisfactory from all the points of view of activity, productivity and C balance, allowing to limit the heat input to the reactor with respect to operation at 750 °C.

The

o

-cresol is one of the VOCs toxic compounds, it is used as pharmaceutical intermediates, reagents, custom synthesis and as a solvent, disinfectant and chemical intermediate for a wide variety of products including resins, paints and textiles. Efficient treatment technologies are required to reduce

o

-cresol concentration in wastewater to acceptable levels because

o

-cresol is hazardous even at low concentration. Biological treatment methods have been researched to treat

o

-cresol in wastewater. Several studies have shown that

o

-cresol can aerobically degraded by a wide variety of microorganisms.

In this study, a series of experiments were performed to examine the effects of the mineral medium composition and the pH on

o

-cresol removal. In this purpose,

o

-cresol biodegradation was carried out in a batch reactor containing mixed bacteria; the temperature (30 °C), the stirring velocity (200 r/min), the KH

2

PO

4

concentration (1.5 g/L), the K

2

HPO

4

concentration (2 g/L), and

o

-cresol concentration (100 mg/L) were kept constants. The initial pH was varied in the range 5–9 and the mineral components were tested in the following concentration ranges: 0–2 g/L for nitrogen sources (NH

4

Cl, KNO

3

, and NH

4

NO

3

), 0–0.5 g/L for NaCl, and 0–0.2 g/L for MgSO

4

. Their effects on

o

-cresol biodegradation and specific growth rate were examined. The shorter biodegradation time of

o

-cresol was 35.6 h for NH

4

Cl, NaCl, and MgSO

4

concentrations of 1 g/L, 0.3 g/L, and 0.1 g/L, respectively. Maximum specific growth rate (0.33 h

−1

) and total

o

-cresol removal (99.99 %) were recorded for an optimal pH value of 8.

Glycerol is the main by-product in biodiesel production. The increasing production of biodiesel has resulted in significant amount of glycerol deposition. Esterification of glycerol with acetic acid is a kind of method to consume excess glycerol. The valuable chemicals like that bioadditives are produced in this method. Zr(SO

4

)

2

·4H

2

O loaded chitosan catalytic membrane was prepared by the solution casting method and used as catalyst for esterification of glycerol and acetic acid. The reactions were performed in a batch reactor and in a pervaporation catalytic membrane reactor (PVCMR). The structure of the membranes was investigated by means of Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of esterification of acetic acid and glycerol show that the conversion was slightly improved with the Zr(SO

4

)

2

·4H

2

O content in the membrane at a fixed chitosan content. The reaction rate constant increased with increasing acetic acid/glycerol molar ratio, amount of catalyst loading in the catalytic membrane and reaction temperature. Higher conversion values were obtained by PVCMR.

The adsorption of penicillin onto dried biomass was studied as a function of initial penicillin concentration and temperature. The maximum penicillin adsorption yield was obtained at the temperature of 30 °C; the equilibrium uptake increased with increasing initial penicillin concentration. The Freundlich and Langmuir adsorption models have been used for the mathematical description of the adsorption equilibrium. The results show that experimental data fit perfectly the Langmuir model. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data. The latter provided the best correlation of the experimental data compared to the pseudo-first-order model.

Hydrogen detection becomes, generally, an actual problem as “H-technologies” are widely presented in the different areas of industry. On following these tendencies, we have made an attempt to consider possibilities of investigation of switchable magnetic properties of hydrogen-containing dilute paramagnetic metal alloys, on using information obtained in previous considerations of metal hydrides and of localized magnetic moments in metal alloys.

TiO

2

thin films were deposited on glass substrates by hydrolysis and condensation of tetraethyl orthotitanate [TEOT], and the pH of the solution is controlled by the addition of concentrated HNO

3

. The effect of thickness of the films on structural, optical, and photocatalytic properties has been investigated. The phase transformation temperature was determined by DTA-TGA; the nature of the phases and the crystallite size of TiO

2

are derived from X-ray diffraction patterns. From the transmittance spectra of the layers, the refractive index, and thickness were calculated using the envelope method. The results show that the films crystallize into anatase phase only with grains size in the range of 17 nm. The films showed high transmittance in the visible (93 %) and opaque in the UV. Finally, the as-prepared TiO

2

films exhibit high efficiency in the photocatalytic degradation of MB and RdB.

The aim of this work is to study the effect of lights, dark, and cooling time on the electrochemical properties of the photovoltaic silicon working electrodes in 0.5 M sulfuric acid medium. The silicon samples were heated until 1,200 °C in appropriate oven and cooled with the injection of argon gas at a different flow rates that allow the decrease of the temperature to 650 °C, respectively, after 2, 4, and 8 h. By corrosion potential vs. time, resistance polarization technique and Tafel plot curves, we have studied the behavior of silicon electrodes, and we have noticed that the electrochemical properties of silicon were affected by temperature of the medium, by the cooling time and by the lighting power. The microscopic examination of the electrodes shows a significant change in the morphology of materials after the polarization tests.

Solid state nuclear track detectors (SSNTDs) have been widely used as sensors of radon and progeny in long-term dosimetry because they exhibit high detection properties while their cost is very low. Alpha-particle energy calculating codes, specific for every incident particle, increase the Monte-Carlo simulation time significantly. The expression of the alpha particle energy as a function of the distance travelled in SSNTD CR-39 was recently introduced as an alternative approximation for the simulation method. This chapter focused on modelling the response of bare CR-39 detectors to alpha-particles emitted by radon and progeny, through Monte-Carlo methods. In order to determine the efficiency of a combined use of bare CR-39 and cup-type detectors in radon measurements, theoretical and experimental CR-39 efficiency factors for alpha-particles were calculated. Modelling rendered calculation of effective volume for CR-39 detector, based on energy and angular distributions of alpha-particles emitted due to decay of radon and progeny. The relationship between equilibrium factor

F

and the recorded track density values ratio (of bare and cup-enclosed SSNTDs, respectively)

R

was calculated. The sensitivity factor

k

B

for bare CR-39 was found equal to

k

B

 = (4.6 ± 0.6) [tracks × cm

−2

]/[kBq × m

−3

 × h] (assuming the Jacobi’s steady-state model), a value not significantly different from the corresponding

k

R

cup-type value for radon and progeny.

The objective of this study is the valorization of certain local natural clays by their use in treatment of industrial wastewater. For this purpose, we carried out discoloration tests of effluents by adsorption using two natural clays from two different deposits, one located in Maghnia (MC) and the other in the region of Bechar (BC). The adsorption tests were conducted on a basic dye methylene blue (MB). The effects of temperature, initial dye concentration, contact time, and solution pH on adsorption were studied. The adsorption capacity increased with an increase in adsorbate dosage and a decrease in ionic strength. The equilibrium time was found to be 90 min for full equilibration. Langmuir isotherm model fitted well the equilibrium data for the two sorbents (BC and MC) comparing to the Freundlich isotherm models. The monolayer adsorption capacity of AB and AM for methylene blue (MB) was found to be 223.714 and 510.204 mg/g, respectively. Also, the adsorption processes were endothermic and spontaneous in nature.

In recent years, the placement of phasor measurement units (PMUs) in wide area measurement systems has gained much attention. This work presents a binary teaching learning-based optimization (BTLBO) algorithm for the optimal placement of PMUs. The optimal PMU placement problem is formulated to minimize the number of PMUs installation subject to full network observability at the power system buses. The proposed method is applied to the IEEE14-bus, 30-bus, 57-bus-118 bus systems. The results show that the whole system can be observable with installing PMUs on less than 25 % of system buses. To validate the approach, the results are compared with those reported in literature and has shown that the BTLBO algorithm is efficient for solving the optimal PMU placement problem.

This study focuses on the extraction of essential oil of

Thymus pallescens

, using a new extraction process developed in our laboratory: steam distillation assisted by microwaves also called microwave steam distillation (MSD). This process is a combination of traditional techniques, namely, a steam distillation (SD) and an innovative technology, a microwave heating. Indeed, heating by microwaves helped initiate and build the mass and heat transfer inside the plant matrices outward which results in a considerable reduction in the extraction time. Kinetic study of extraction, optimization of operating conditions, and antioxidant activity of essential oil were conducted. The selected operating parameters are the steam flow rate and the microwave heating power.

The yield obtained by microwave steam distillation is comparable to that obtained by the conventional steam distillation, while the extraction time is greatly reduced: 5 min for MSD extraction against 20 min for the SD. The best performance was obtained with a power of 400 W and steam flow rate of 10 g·min

−1

. Determination of antioxidant activity by DPPH test of

Thymus pallescens

essential oil obtained by both processes showed that the method assisted by microwaves has an influence on the ability of essential oil to inhibit DPPH radical. Indeed, the essential oil extracted by this process is more effective than that obtained by conventional steam distillation. Moreover, the inhibition rate of DPPH radical is more important for essential oil than that of synthetic antioxidant (BHT and BHA) for concentrations higher than 400 mg·L

−1

. In addition, the values obtained show that the essential oil has a better antioxidant activities in comparison with its main component, namely, the carvacrol.

Nanocomposites with polymer matrix are reinforced by SWNTs, one identified as excellent candidates for applications: electronics, photovoltaics, and mechanics.

In this direction this work presents a study of the interactions of the composite carbon nanotubes/polymers. In the first part, the effects of functionalization and chirality (the length and the diameter) of the nanotubes on the Young modulus and on interaction energies, one simulated and determined by molecular dynamics, and DFT hile basing itself on physical model R.V.E of the nanocomposites SWNT/polyethylene. Results of interaction energies and of the Young modulus (longitudinal and transverse) validate the tendency of the experimental results reported in the literature. An increase of lengths and a reduction in the diameters of the nanotubes imply an increase in interaction energies and of the Young modulus, which means good mechanical behavior nanocomposites.

Increasing world population and consequent increase in fossil fuel consumption emerge the necessity of looking for new sources of energy, resources that are clean, cheap, and renewable. The extracted energy from the sea is one of the alternatives of fossil fuels. This energy is available either in the form of tidal or wave energy. Wave energy converters are devices which convert the permanent sea waves to electrical energy. In order to achieve this technology and according to the terms of the sea conditions, developing the numerical modeling in a numerical wave tank is very important for modeling the system and analyzing its performance in different circumstances. So the sea conditions can be applied to this system. Simulation of linear and nonlinear waves in numerical wave tank has been one of the most important topics of interest to researchers and scholars working in the areas of the marine industries. Extensive numerical studies have been conducted using different methods in the past years. Among them, boundary element method is one of the most useful methods for modeling the boundary value problems, particularly for problems related to the hydrodynamic of marine structures. It is evident from literature that this method is very efficient and produces very accurate results for problems considered in this field. In this paper, due to capabilities of the boundary element method and using the Euler-Lagrangian method, nonlinear waves generated by a piston wave maker in a two-dimensional wave tank are investigated. For time evolving of wave in the simulation and solving the free-surface boundary condition equations, the conventional Euler-Lagrangian method is used too. For evaluation of results, a sample wave is chosen for simulation, and its result is compared with a result of an analytical method. Finally, a wave with characterization of average Caspian Sea waves is selected for simulation. The simulations have shown that if the wave maker oscillates with the average wave height and period of the Caspian Sea waves, what will be the characteristics of the generated waves, then the extractable energy potential is obtained from it.

Design has become one of the most essential tasks for human beings throughout the history of mankind. The accurate modeling and analysis of solid bodies moving in free fluid media (such as canals) for velocity, pressure, and forces have become quite significant. In conjunction with this, it is a challenging task to design solid bodies with complex geometries and structures in multidimensional form and it needs the utmost care and attention. Moreover, it is inevitable to develop and design some new systems that will enable us to reduce the energy requirements to minimum levels because nowadays saving energy has become one of the hottest issues for attaining sustainability. In this study, energy-efficient and -effective solid bodies are designed and analyzed by developing a two-dimensional model to study the distributions of flow velocity, pressure, and forces in free and restricted environments. The generalized model solutions are achieved in M

atlab

. The results are then discussed for optimum conditions.

Taylor–Couette flows are frequently reencountered on engineering processes, such as for cooling the rotors of electric motors by admitting cold air and improving the mixing in the combustion area, for the injection of fuel into the cylinders of gasoline engines, for the injection of just-prepared emulsions on diesel engines, etc. On its simplest configurations, Taylor–Couette systems (TCS) are widely studied when one or both cylinders steadily rotate. Limited studies are available as concerned on the acceleration-deceleration of one or both cylinders. This paper deals with the effect of acceleration-deceleration imposed to the inner cylinder of the CTS on flow instabilities. Imposing progressive periodic transitional motions through the cylindrical CTS walls alters the stability of the flow. The objective of this work is to study the flow dynamics and interactions between wall and vortices while imposing progressive periodic motions. We used the electrodiffusion (ED) method, known also as the polarography technique. The apparition and disappearance of the regime transitions, due to the acceleration-deceleration of the inner cylinder speed, on the frequency response of the ED sensor were illustrated and discussed. The regimes’ instabilities and the corresponding Taylor numbers of the first and the second transitions of TC flow were determined. The results show coherence between the temporal wall velocity gradient (determined from the mass transfer rates) and the flow turbulent characteristics, particularly at the transitions between the Couette flow (CF) regime, the wavy vortex flow (WVF), and the modulated wavy vortex flow (MWVF). Instantaneous mass transfer rate and velocity gradient have been compared for the CF, the WVF, and the MWVF regimes. The apparition of small then large vortices, when the Taylor number increases, i.e., from laminar regime to turbulent one, affects the mass transfer and the wall shear rate. Sensor inertia effect and a slight hysteresis effect, due to sudden periodic flow velocity decrease, were detected. The ED results allowed testing the robustness of the inverse method, based on the inversion of the convection-diffusion equation, on mass transfer to determine the wall shear rate.

In this study, the two main transport characterization problems of the foam flow are studied: foam flow stability, through the evolution of the velocity at the core of the foam, and rheology, with the study of the wall shear stress over the lateral walls, for different void fractions. The same velocity profile (block flow, mean velocity 1.75 cm/s) is imposed to the foam flow, at the inlet of the channel, for several void fractions (air/water relation) going from 55 to 85 %. Later on these ones are passed through a singularity (fence) to study the different behaviours induced by the particular properties of each case. The velocity fields, the lateral liquid film thickness and the lateral wall shear stress fields are obtained and compared with one another to comprehend and remark the difference in such a complex flow. The results show that as we move closer to very dry foams the shear at the foam core increases and its velocity becomes higher. However, the wall shear stress at the lateral wall does not present big deviations from one void fraction to the other.

The acoustic emission (AE) technique is widely applied to develop early fault detection systems, on which the problem of a signal-processing method for an AE signal is mainly focused. In the signal-processing method, envelope analysis is a useful method to evaluate the bearing problems and the wavelet transform is a powerful method to detect faults occurring on rotating machinery. However, an exact method for the AE signal has not been developed yet. Therefore, in this chapter two methods are given: Hilbert transform and discrete wavelet transform (IEA), and DET for feature extraction. In addition, we evaluate the classification performance with varying the parameter from 2 to 15 for feature selection DET and 0.01–1.0 for the RBF kernel function of SVR; the proposed algorithm achieved 94 % classification accuracy with the parameter of the RBF 0.08, 12 feature selection.