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In this study, ALOS-2 PALSAR L-band dual-pol (HH and HV) synthetic aperture radar (SAR) images were used for above ground biomass (AGB) estimation of Shisham (Dalbergia sissoo) tree species in the managed forest of Chichawatni Irrigated Plantation, Sahiwal District, Punjab, Pakistan. A total of 15 plots were surveyed during the field campaign and locally developed tree species-specific allometric equation was used for AGB calculation. The SAR images were pre-processed and calibrated to sigma nought (dB) for statistical AGB modeling. Nonlinear regression models between field-based AGB (ton/ha) and SAR backscatter sigma nought (dB) values give R2 (0.47 and 0.55) and RMSE (1.18 and 1.87) values for HH and HV-pol data, respectively. AGB maps generated through these regression models from both HH and HV-pol data show similar AGB values and spatial patterns. Due to a small number of sample plots, the Leave-One-Out Cross-Validation (LOOCV) proxy validation method was used for model validation, between estimated and predicted backscatter sigma nought (dB) values. The validation R2 values are small; however, outliers are identifiable in the validation scatterplots. The AGB maps from this study are useful as a first estimate of AGB values from remote sensing in the study region, especially in the context of the REDD+ program.

Background: Epilepsy is a common disorder in South Africa and the literature indicates that many patients do not access treatment. The reasons are complex and include a poor knowledge about causes, symptoms, diagnosis and treatment (medical knowledge). This study aimed to assess the medical knowledge of isiZulu-speaking people with epilepsy (PWE) who attend a combination regional and district hospital in the eThekwini district in KwaZulu-Natal Province. Method: This was a prospective, cross-sectional, descriptive study. Data were collected using a validated data collection tool for assessing the medical knowledge of PWE and analysed descriptively. Results: The questionnaires were completed by 199 PWE, with the general level of schooling being low and half being unemployed. Knowledge around causes, symptoms, diagnosis and treatments was good, but there were significant gaps in knowledge that may affect morbidity and mortality. Discussion: The findings will serve as a useful guide to develop both preventive and educational interventions to enhance knowledge around the causes and treatment of epilepsy in this population. It is important that such interventions also consider family and healthcare providers. Conclusion: There were considerable gaps in the medical knowledge of isiZulu-speaking PWE’s, indicating the need for an educational intervention to improve their understanding of epilepsy. Further research is needed-using a range of tools to ensure that the data is reliable and valid–if the results are to be generalisable to the rest of the province and South Africa.

In this study, a novel approach has been proposed as a solar chimney integrated with an external heat source to extend the system operation during the absence of solar energy. Flue gas channels have been utilized to exchange heat with the air inside the collector of the solar chimney. The hybrid solar chimney has been investigated numerically by ANSYS-Fluent software, using discrete ordinates radiation model. The hybrid system was simulated in 3D, steady-state by solving Navier-Stokes and energy equations. The numerical results have been validated using experimental measurements of a conventional solar chimney. The influence of flue channels on the system performance was predicted and analyzed in hybrid mode. With 0.002 kg/s of flue gas at 100°C injected in flue channels during the daytime; hybrid mode results demonstrated enhancement of 24% and 9 % for velocity and temperature, respectively. The power generation was enhanced by 56%. It has been proved that the proposed technique is able to resolve the set back of night operation problem of the solar chimney plants.

Heat loss is an important factor in the performance of the solar receiver for concentrated solar systems (CSP). This study presents a proposed model for a new design for the receiver using an evacuated tube that has been performed to reduce convection loss and radiative heat losses with a zigzag distribution to minimize spillage losses. In this study, simulation results showed that the energy input increases with increased solar irradiation; the increase ranges from 3429 to 5584 W and 1879 to 3875 W at 9 AM and 13 PM for preheater and superheater respectively. The thermal efficiency of the receiver was around 72%.

Solar thermal plants are among the most promising technologies to replace fossil fuel standing applications. Among solar thermal technologies, parabolic troughs are considered as the most mature application in the market. The objective of this paper is to elaborate on comparison results of three different topologies of solar parabolic troughs field, in terms of performances and energy production. Thermolib software was used to perform the proposed power plants simulation with direct steam generation. Applying the proposed models. These models simulate the behaviour of both the solar field and the power block of a 1.2 kW solar thermal power plant. The results of this analysis demonstrating that the use of steam separator and superheater in a stand-alone solar power plant model is more advantageous in terms of steam temperature, steam quality and net electricity production in comparison to other models. The optimum topology showed that the maximum temperature of steam outlet reach 221°C, steam quality reach 1 and efficiency of power plant around 19.6% for model 3.

With the fact that Malaysia is one of the fast- growing countries, demand of energy increment is rapid. Malaysia is able to obtain ample amount of annual solar radiation due to its location at equator. If this is utilized proficiently and effectively, then, it can suffice the domestic needs as well as the industrial needs in terms of energy consumption. This article proposes a parabolic Trough Power Plant which is designed with 1.2 kW net electric output. Consequently, the results of theoretical calculations are detailed in the article, while, ensuring the analysing of design proposed through the MATLAB software. The results showed that by making use of aperture having an area of approximately 80 m2, maximum useful heat gain of 20701W at 13:00 pm was attained in March. The maximum net power is 11.84 kWh/day in February.

Many countries started to adopt clean energy sources, where solar energy is the first priority. Solar chimney power plant was selected in this study as a system which converts solar thermal energy to electrical power. In this research, hybrid solar chimney power plant model has been proposed as a day and night functional integrated system using external heat source to enhance the system performance and cover the setback of solar absence at night and cloudy days. With the help of ANSYS Fluent software, three-dimensional steady-state of Navier-Stokes and energy equations have been solved. Realized k–∊ two equation turbulent model equations and discrete ordinates (DO) radiation model equations were solved for the conventional model. The results were validated using experimental measurements. Afterward, the influence of thermal enhancing channels installation on the system performance was predicted and analysed in hybrid mode. The simulation results showed that this system could enhance the plant during the day. Percentage of enhancement was 10% and 14% for velocity and temperature respectively, and the power output percentage enhancement was 18% when the solar intensity was 1000 W/m2, and external heat source mass flow rate and the temperature for each channels was 0.015 Kg/s and 100°C respectively, in comparison with the conventional model.

A novel concentration solar evacuated receiver tube collector is proposed in this study. Details of design and simulation of the heliostat field are presented. The proposed system uses a heliostat stadium arrangement to focus sunlight towards a receiver (evacuated receiver tube). Heliostat field which looks like stadium arrangement is proposed an alternative system of the tower in the power tower plants to cancel the shading / blocking losses. In this study, simulation results showed that the energy input increases with increased solar irradiation; the increase ranges from 288 to 470W/m.The maximum amount of energy inputs that can be obtained in the receiver for the collector is around 470W/m for the maximum solar density of 688W.m2. In the solar is 402 W/m2, and the useful energy of collectors is about 288 W/m and the thermal efficiency of the receiver was around 23%.

With the rapid rise of energy consumption in the world, lowering the energy needs of houses and buildings can have a significant effect on future of energy demand and consumption. This paper presents experimental investigation results on the effectiveness of the natural and forced ventilation in prototype of zero-energy office. The main aim of the different ventilation systems is to improve the thermal comfort within the office. The installed forced ventilation system achieved a 6°C drop in maximum temperature within the office and improved the thermal comfort by 46%.

Solar central receiver plays a considerable role in the plant output power; it is one of the most important synthesis in the solar power tower plants. Its performance directly affects the efficiency of the entire solar power generation system. In this study, a new designed receiver model based on evacuated solar tube was proposed, and the dynamic characteristics of the developed receiver were investigated. In order to optimise and evaluate the dynamic characteristics of solar power plant components, the model investigates the solar radiation heat conversion process through the developed receiver, where the energy and mass conservation equations are used to determine the working fluid temperature and state through the receiver parts, beside the calculation and analysis of the thermal losses.

In this competitive business world one way to increase profitability of a power production unit is to reduce the operation and maintenance expenses. This is possible if the gas turbine availability and reliability is improved using the appropriate maintenance action at the right time. In that case, fault diagnostics is very critical and effective and advanced methods are essential. Gas turbine diagnostics has been studied for the past six decades and several methods are introduced. This paper aims to review and summarise the published literature on gas path diagnostics, giving more emphasis to the recent developments, and identify advantages and limitations of the methods so that beginners in diagnostics can easily be introduced. Towards this end, this paper, identifies various diagnostic methods and point out their pros and cons. Finally, the paper concludes the review along with some recommended future works.

To develop and integrate solar hybrid system into conventional air conditioning system which provides the same cooling load with considerably less electricity demand. Solar evacuated tube and DC compressor are used for compressing the refrigerant in an air conditioning system, thus effectively reducing the air conditioning electricity consumption by up to 45%. For the flow through type selected geometry of the designed evacuated U-tube collector, a three dimensional simulation and analysis of the thermal performance was done, using the solar ray-tracing model provided by the ANSYS-FLUENT software.

The development in the field of refrigeration and air conditioning systems driven by absorption cycles acquired a considerable importance recently. For commercial absorption chillers, an essential challenge for creating chiller model certainly is the shortage of components technical specifications. These kinds of specifications are usually proprietary for chillers producers. In this paper, a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations is presented. The chiller studied is Lithium bromide-water with capacity of 1250 RT (Refrigeration Tons). The governing equations of the dynamic operation of the chiller are developed. From available design information, the values of the overall heat transfer coefficients multiplied by the surface area are computed. The dynamic operation of the absorption chiller is simulated to study the performance of the system. The model is able to provide essential details of the temperature, concentration, and flow rate at each state point in the chiller.

For the flow through type selected geometry of the designed evacuated tube collector ETC, a three dimensional simulation and analysis of the thermal performance was done, using the ray-tracing solar load model provided by the ANSYS-FLUENT software. In this model the solar radiation heat flux is solved using fair weather condition radiation equations, and then solar radiation load is considered as a heat source term in the energy equation. The thermal effects of the fluid flow and heat transfer in the collector, temperature fields as well as the solar radiation distribution, and other related factors under the different conditions have been discussed and analyzed.

Les auteurs ont étudié, au Pakistan, la réponse de vaches laitières, Sahiwal, Sahiwal X Jersey et Sahiwal X Holstein - Frison au stress de la saison sèche en observant les variations journalières de la température rectale, du pouls et du rythme respiratoire, en fonction de la température et de l'humidité ambiantes. Ces observations qui ont concerné 5 animaux par race ont montré qu'il n'existait pas de différence appréciable en ce qui concerne le mécanisme de la thermo régulation parmi ces trois races. Les variations dans la fréquence du pouls suivent à peu près le même rythme chez les trois groupes d'animaux, avec une différence significative élevée (P < 0.01) entre les divers mois de l'été, le rythme le plus bas se situant à la mi-juin où la température et l'humidité sont à leur niveau le plus bas et le rythme le plus élevé à la mi-juillet alors que l'humidité ambiante est à un niveau élevé. Le rythme respiratoire qui représente le paramètre accusant le plus de variabilité entre les trois races, s'élève rapidement et de façon considérable chez les Sahiwal X Holstein Frison, sensiblement moins chez les Sahiwal X Jersey pour atteindre son maximum à la mi-juillet (alors que chez les Sahiwal ce rythme reste à peu près le même tout au long de la saison sèche). Ils concluent que c'est la race Sahiwal qui supporte le mieux le stress thermique de la saison sèche

Les échantillons du sérum de 46 chevaux atteints de surra et de 46 chevaux indemnes ont fait l'objet d'une analyse chimique en ce qui concerne les protéines totales et les fractions électrophorétiques. Les protéines totales des animaux indemnes ne montrent pas de différences significatives par rapport à celles des animaux infectés. Le taux d'albumine atteint 3,16 g/100 ml chez les chevaux sains alors qu'il est de 1,36 g/100 ml chez les chevaux infectés. L'abaissement du taux d'albumine atteint au moins 80 p. 100 quand on le compare à celui des chevaux en bonne santé. Les résultats indiquent des différences significatives pour les globulines totales et les gamma-globulines entre les deux groupes d'animaux mais non pour les alpha et bêta-globulines. Le rapport albumine/globuline est significativement peu élevé dans le groupe de chevaux infectés