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The thermal energy available in the form of solar radiation is collected and converted into heat with the help of a solar air heater. The flow and thermal characteristics change significantly with the cross-sectional shape of the flow passage. The effect of hemispherical dimple-cavities that were employed over the heat-collector plate has been analyzed based on the flow and heat characteristics of a triangular solar air heater. A comprehensive investigation of roughness and flow parameters is carried out experimentally, while the flow dynamics over the heat-collector plate are predicted using commercial software (ANSYS). The remarkable results are observed in terms of Nusselt number and friction factor with the use of dimples over the heat-collector plate in the solar air heater. The higher heat transfer is noticed at the training edge in comparison to the leading edge of the dimple. The best augmentation in Nusselt number obtained is of the order of 5.33 that is observed for transverse-pitch ratio, longitudinal-pitch ratio and relative dimple depth values of 11, 11 and 0.039 respectively, at Reynolds number value of 2160. A close fit curve was obtained between the values obtained from the developed correlation and experimental values with a maximum error of 6.61% and 7.03%, respectively.

Roughness is one of the effective and promising method to improve heat transfer through the solar air heater. The cross-sectional shape of roughness provided on the absorber plate shows a strong influence on solar air heater performance. In this work, the influence of various roughness-elements (such as semi-circular, circular, triangular, square, rectangular) has been investigated on flow dynamics as well as thermal characteristics of solar air heater and these geometries were investigated in triangular passage solar air heater. Commercial software is used for simulating heat and flow dynamics of roughened solar air under steady-state conditions. At Reynolds number of 18.7 × 103, the best thermohydraulic performance parameter (TPP) obtained is 2.75 for forward-chamfered rectangular rib (with e/w = 2). The maximum value of TPP obtained for various roughness geometries decrease in the order of 2.68, 2.57, 2.45, 2.06, 1.79, and 1.60 for backward-chamfered rectangular rib (with e/w = 2), rectangular rib (with e/w = 2), rectangular rib (with e/w = 0.67), square rib, semi-circular rib, and circular ribs, respectively.

Baffles are used for heat transfer enhancement in heat exchanger tubes. However, they also increase the friction factor in the flow channel. Perforation in baffles further augments the heat transfer. Moreover, it was also noticed that the perforations in the baffles strongly reduce the associated pressure drop in the tube. Some novel ideas for baffles therefore need to be produced, which can cumulatively intensify the performance of the heat exchanger conduit. Therefore, in the present study novel design of perforated angular-cut baffles is considered for the experimental investigation in the turbulent flow regime for thermodynamic and heat transfer investigation. Air is taken as the working fluid with Reynolds number varying from 10,000 to 52,000. Two arrangements of baffles, viz. inline and alternate, are considered for the experimentation. The parameters considered for the investigation are as follows: three perforation ratios (H), two angles of attack, (α) and two pitch ratios (P). The results obtained from the investigation show an enhancement in Nusselt number, Nu, and friction factor, f, both. The highest augmentation in heat transfer is noted for alternate segmental baffles (ASB) with a perforation ratio (H) of 0.15, a pitch ratio (P) of 0.1 and an angle of attack (α) of 45°, while for segmental baffles (SB), a perforation ratio (H) of 0.20, a pitch ratio (P) of 0.2 and an angle of attack (α) of 30° give the minimum heat transfer. An increase in heat transfer coefficient is also noticed with an increase in angle of attack (α). ASB show superior heat transfer compared to SB, and ASB have an enhanced Nu compared to SB for a pitch ratio of 0.1, an angle of attack of 45° and a perforation ratio (H) of 0, 0.15 and 0.2, which is about 39.5%, 37.9% and 42.18%, respectively. Nusselt number, Nu, and friction factor, f, correlations were proposed, and a good agreement was found between the test obtained data and predicted data. The thermo-hydraulic performance parameter for all the examined cases was greater than unity.

Formaldehyde is one of the vital chemicals produced by industries, transports, and domestic products. Formaldehyde emissions adversely affect human health and it is well known for causing irritation and nasal tumors. The major aim of the modern indoor formaldehyde control study is in view of energy capacity, product selectivity, security, and durability for efficient removal of formaldehyde. The two important methods to control this harmful chemical in the indoor environments are photocatalytic oxidation and catalytic oxidation with noble metals and transition metal oxides. By harmonizing different traditional photocatalytic and catalytic oxidation technologies that have been evolved already, here we give a review of previously developed efforts to degrade indoor formaldehyde. The major concern in this article is based on getting the degradation of formaldehyde at ambient temperature. In this article, different aspects of these two methods with their merits and demerits are discussed. The possible effects of operating parameters like preparation methods, support, the effect of light intensity in photocatalytic oxidation, relative humidity, etc. have been discussed comprehensively.

Roughness is an effectual way to augment heat transfer in solar air heater (SAH). Multiple arcs (with gap) type of roughness has considered in this work and experimentation is performed to determine their effect on thermo-hydraulic performance of rectangular channel SAH duct. The experimentation is performed to analyze the effect of different parameters (both roughness as well as flow). Roughness parameters; number of gaps (Ng) and rib gap width (g) has considered with fixed value of pitch (p), rib width (w), rib height (e), arc angle (or). The effect of considered parameters was investigated experimentally on Nusselt number (Nu) and friction penalty (f). Strong impact of roughness parameters is observed on the Nusselt number (Nu) and frictional penalty (f). In comparison to smooth duct, 5.57 times higher Nusselt number is obtained along with increase of frictional penalty by 4.46 times at number of gaps (Ng) of 3. The domination of Nusselt number (Nu) over frictional penalty (f) resulted tremendous increment in thermo-hydraulic performance (TPP) with the highest value of 3.46 at Ng = 3 and relative-roughness-width (g/e) = 1.0.

In the present study, the heat transfer and thermal performance of a helical corrugation with perforated circular disc solar air-heater tubes are predicted using a machine learning regression technique. This paper describes a statistical analysis of heat transfer by developing an artificial neural network-based machine learning model. The effects of variation in the corrugation angle (θ), perforation ratio (k), corrugation pitch ratio (y), perforated disc pitch ratio (s), and Reynolds number have been analyzed. An artificial neural network model is used for regression analysis to predict the heat transfer in terms of Nusselt number and thermohydraulic efficiency, and the results showed high prediction accuracies. The artificial neural network model is robust and precise, and can be used by thermal system design engineers for predicting output variables. Two different models are trained based on the features of experimental data, which provide an estimation of experimental output based on user-defined input parameters. The models are evaluated to have an accuracy of 97.00% on unknown test data. These models will help the researchers working in heat transfer enhancement-based experiments to understand and predict the output. As a result, the time and cost of the experiments will reduce.

Solar air heater (SAH) is a device used to convert sun radiations into heating applications. To improve its performance, the heat absorbing side of SAH is modified with the ribs called roughness. The flow characteristics and augmentation of heat due to square shaped ribs in SAH having triangular cross-sectional passage has been simulated using computational fluid dynamic (CFD) technique. The CFD simulations consisted of design and modeling of SAH. Two different roughness parameters has been considered in the analysis i.e. relative roughness pitch (P/e) and relative roughness height (e/D) and their value ranges from 5 to 13 (in four sets) and 0.013 to 0.05 (in four sets), respectively for Reynolds number varies from 3900 to 17900. Better augmentation of heat has been seen in SAH by providing ribs on the absorber plate. The highest improvement in heat transfer is seen of the order of 97% in P/e value of 10 and e/D value of 0.05 at Re of 17900. The thermohydraulic performance parameter (TPP) is also calculated and have highest value of 1.97 for P/e value of 10 and e/D value of 0.05 at Re of 17900. Correlation has been developed for both friction factor and Nusselt number based on observed results.

The performance models for high-temperature metallic recuperators considering one and two-dimensional heat transfer are presented. In one-dimensional model, an explicit expression to represent the effect of both the temperature and product of partial pressure and mean beam length on the emissivity is developed using emissivity charts. The effect of upstream and downstream surroundings is neglected. A two-dimensional heat transfer model is developed using zone method along with sum-of-gray-gases approximation to study the effect of upstream and downstream surroundings on performance. The results from the two models are compared. For lower values of inlet flue gas temperatures and higher mass flow rates, one-dimensional model predicts results within 5% of two-dimensional model. One-dimensional model provides a simplified solution for the assessment of recuperator performance but predicts the surface temperature distribution on a relatively lower side for higher inlet flue gas temperatures and low mass flow rates.

The plate fin heat exchangers usually have either rectangular or triangular shaped flow passage. In comparison to triangular flow passage, rectangular flow passage gives comparatively higher heat transfer at the cost of higher pumping power. In the present investigation, flow passage is modified by rounding the corner of triangular passage to investigate the heat and flow characteristics of air flowing through it. Comparison of performance between modified and rectangular flow passage has also been presented and discussed. The radius of curvature of the rounded corner has been kept constant with value of 0.49 times duct height (H). The dimple was also fabricated at the inner side of the flow passage and arranged in rectangular array. Distance between them was defined by two different dimensionless parameters, relative transverse width (x/h), and relative streamwise length (z/h), whereas, dimensionless height of the protrusion is defined by relative dimple height (h/D). Noticeable increment in both heat transfer and friction factor has been observed by modifying the duct corners and 2.98 times increment in Nusselt number resulted due to dimples in modified duct for h/D, x/h, and y/h value of 0.44, 10, and 10, respectively, in comparison to smooth duct at Reynolds number of 19,500. For similar combination of roughness parameters, highest frictional penalty was estimated with value of 4.46 times that of the smooth duct at Reynolds number of 4400. Additionally, the comparative assessment of heat transfer enhancement (Nuenh), frictional penalty (fpenalty), and thermohydraulic performance index (THPi) has also been carried out to understand the suitability of round cornered duct. In comparison to protruded rectangular duct, 28% higher THPi is obtained in modified duct under similar conditions.

The present investigation focuses on need of bio-based lubricants which are biodegradable and environmental-friendly along with improved oxidative stability. The global demand for lubricants is expected to increase as the demand for engine oil for new motor vehicle increases with the increase in number of vehicles. The depleting nature of mineral oils and its adverse impacts on environment has raised the attention of scientists towards the utilisation of renewable bio-based lubricants. The increased environmental awareness is a primary driving force for the new technological developments. In the present study, waste cooking oil (WCO) biodiesel is used as a feedstock for blending with lubricating oil as it is the economical source for the production of biodiesel. WCO was chemically modified by transesterification process. The effect of friction and wear behaviour on performance of cylinder liner-piston and cam-tappet in valve train under lubricating condition has been studied using high frequency reciprocating test rig (HFRR) and pin on disc tester (POD). In addition, the investigations of lubricant variants after the test were also carried out with analytical ferrography to analyse the wear debris in the lubricants. The 10% blending of SAE20W40 with WCO biodiesel exhibits improved results in terms of coefficient of friction and wear scar diameter (WSD).

Consumption of fossil fuels is an important issue which is to be addressed for better tomorrow due to its dreadful implications on the environment and its depleting nature is also a concern. Hence, the need of more diversified research in alternate sources arises, even to the point of complete elimination of diesel from compression ignition (CI) engines by using dual fuels; a mixture of high and low viscous fuel. In the present study, aamla seed oil biodiesel (AB) and eucalyptus oil (EU) blends were used as fuels for CI engine. Aamla seed oil was chemically modified with transesterification process. Results demonstrated that use of dual fuel can give satisfactory performance in a standard diesel engine without any tweaking in the engine. From all the tested fuel blends, result shows that a blend of 70% Aamla biodiesel- 30% Eucalyptus oil (AB70EU30) was found to be optimum blend and has potential to replace diesel completely. The performance and combustion characteristics of the engine fuelled with AB70EU30 were found almost in line with diesel. In addition, tailpipe emissions carbon monoxide (CO), unburnt hydrocarbon (HC) and smoke were found to be lower whereas nitrogen oxides emission was found to be almost equivalent with diesel.

In the present time, need of biogenic lubricants is the focusing area which will be biodegradable, avirulent and eco-friendly. Current experimental tests depict the effect of ‘Phyllanthus emblica’ a non-edible feedstock through pin on disc tribo tester. Tests were conducted to evaluate the impact of 0, 10, 20 and 30 % blending of Phyllanthus emblica with SAE20W40 lubricating oil on cylinder liner and piston ring. Promising results have been manifested with 10 % blending of biodiesel (BD) with lubricating oil in terms of coefficient of friction and specific wear rate in comparison with other examined feedstock. For analysis of wear debris in the used oil analytical ferrography was also done. The effects of temperature on wear and friction characteristics have also been discussed.

Today in every nation's agenda, the utmost priority is given to reduce the impact of pollution (emissions related to air and water) that is created through different sources. This pollution is highly impacting our life on the daily basis. The best way is to reduce the pollution by encouraging usage of environment friendly activities. Moreover, the rate by which our conventional (non-renewable) sources of fuel depleting is really alarming and might perish in long run. The only way for the sustainable development is by adopting eco-friendly and renewable sources of fuel. Oxygenated fuel is an alternative fuel for the diesel engine because it is reversible in nature and its emissions are low. This paper has focused on the impact of different modification made in CI (compression ignition) engines in order to work at their optimum level in terms of combustion, emission and performance. The modification in engine had carried out by varying injection pressure (IP), injection timing (IT),compression ratio (CR), combustion chamber geometry etc. Results show that at high value of CR, IP and retardation or advancement of IT shows the improvement in the combustion, performance and emissions characteristics of CI engines. At modified conditions brake specific fuel consumption, unburned hydrocarbon, smoke opacity and carbon monoxide emission decreases and brake thermal efficiency and nitrogen oxide emission increases as compared to without modified ones. The result also shows that retarded injection timing as compared to original injection timing, emission of nitrogen oxide decreases.

The Computational fluid dynamics (CFD) based analysis is carried out to investigate the thermal and hydraulic performance of circular rib roughened triangular passage Solar air heater (SAH). The circular ribs were provided over the absorber plate. The roughness parameter such as relative roughness pitch (P/e) and relative roughness height (e/D) varies from 4 to 20 and 0.015 to 0.06 (in four sets), respectively, the Reynolds number (Re) varies from 4000 to 18000. The flow governing equations were solved using commercial ANSYS (Fluent) software. The predicted Nusselt number (Nu) and friction factor (f) are validated with the available experimental results. The thermal and hydraulic performance of roughened duct is estimated in the form of Nusselt number and friction factor, respectively. The Thermohydraulic performance parameter (TPP) is also evaluated depending on the friction factor (f) and Nusselt number (Nu) values for SAH. The maximum Thermohydraulic performance parameter (TPP) is observed at Reynolds number of 15000 in case of relative roughness pitch (P/e) and relative roughness height (e/D) value of 12 and 0.06, respectively.

The rib provided over absorber plate can improve the performance of solar air heater (SAH). The effect of forward chamfered ribbed absorber plate is studied in the present article. Two new roughness parameters named as rib aspect ratio (e/w) and rib chamfered height ratio (e′/e) has been defined and their influence on the performance of triangular duct SAH is simulated using commercial ANSYS software for fixed range of Reynolds number (Re) which varies from 4000 to 17000. The e/w, relative roughness height (e/D) and e′/e ranges from 0.24 to 1.5, 0.018 to 0.043 and 0 to 1.0, respectively. The ribbed side of duct is heated with constant heat flux of 1000 Wm-2. The three-dimensional model of SAH is developed for the analysis and results are simulated using finite volume approach. The numerical methodology is validated by comparing predicted results with the available results and a close match is seen between friction factor (f) and Nusselt number (Nu). A remarkable change in f and Nu value is observed by varying both Re and roughness parameters. The maximum increase in Nu is observed in case of e/w, e/D and e′/e value of 1.5, 0.043 and 0.75, respectively, at Re value of 17000 and it is of the order of 2.88. The maximum increase of friction penalty is seen in case of e/D value of 0.043 which is of the order of 3.52 times the without ribbed duct at Re value of 4000. With the help of numerically predicted results, a generalized correlation is developed for Nu and f.

Solar air heater (SAH) absorbs thermal radiations from Sun and utilizes it to heat air. The thermal performance of SAH can be improved by using ribs on the absorber plate. In this paper, rectangular geometry of ribs is considered over the absorber plate. The fluid flow characteristics and heat transfer in ribbed triangular duct (with an apex angle of 60°) SAH is analyzed using computational fluid dynamics (CFD). The roughened side of duct is subjected to a constant heat flux of 1000 W m−2, whereas, roughness elements are adiabatic in nature. The three-dimensional model of SAH is developed and numerical simulations are carried out by developing CFD code with the help of finite volume method. The numerical simulations are performed on commercial ANSYS Fluent 12.1 software. A new roughness parameter called rib aspect ratio (e/w) is introduced in this study and its effect on friction factor (f) and Nusselt number (Nu) is investigated along with relative roughness height (e/D) and relative roughness pitch (P/e) for the Reynolds number ranges from of 4000 to 18,000. The values of rib aspect ratio (e/w), roughness height (e/D) and relative roughness pitch (P/e) range from 0.25 to 4.0, 0.02 to 0.04 and 5 to 15, respectively. A considerable increase in friction factor (f) and Nusselt number (Nu) is observed due to rectangular rib in comparison to smooth one. The numerically predicted results are compared with the available results and a good agreement between them is observed with maximum error of ±4.04%. A significant variation in friction factor (f) and Nusselt number (Nu) is observed by varying rib aspect ratio (e/w) values from 0.25 to 4.0. The maximum value of thermohydraulic performance parameter (TPP) is found 1.89 in case of relative roughness pitch (P/e), rib aspect ratio (e/w) and relative roughness height (e/D) value of 10, 4.0 and 0.04, respectively, at the Reynolds number (Re) of 15,000.

Biodiesel can be considered to be the most capable alternate fuel for partial or complete replacement of the fossil fuel. Previous studies on biodiesel-oil blends have demonstrated that the use of double biofuels in engine can be a promising aspect for the complete elimination of diesel from compression-ignition (CI) engines. But its use increases the lubricating oil dilution to some extent due to the chemistry of biodiesel. The present experimental investigation describes the effect of biodiesel-oil blend, oxidized biodiesel-oil blend and diesel dilution in the engine oil by means of high frequency reciprocating rig (HFRR) and pin on disc (POD) friction monitor. Moreover, fresh lubricating oil, lubricating oil which was turned out from AB70EU30 operated engine with modified parameters after 100 h and lubricating oil which was turned out from diesel operated engine after 100 h were also considered for experimentation for clear comparison in results. The effects of engine oil dilution were studied on cylinder liner and piston ring as well as on cam and tappet on valve train. The present study revealed that the 10% dilution of biodiesel-oil blend in lubricating oil shows promising result in terms of coefficient of friction and diameter of wear scar as compared to other tested feedstocks. The effect of oxidation of the biodiesel-oil blend on the performance of engine oil is also assessed in the present study. Analytical ferrography of the used oil was also done to study the wear debris in oil.

Biodiesel is a promising fuel which shows potential and gradually received attention as a best alternate feedstock for diesel engine. Previous investigations have shown that use of double biofuels in a diesel engine can be a promising aspect for complete elimination of diesel from compression ignition engines which will decrease our dependency on fossil fuels. The tribological performance of injection system is primarily based on the lubricity characteristics of the fuel. So, it is imperative to a more diversified research about the impact of using double biofuels in engine. In the present investigation, different biodiesel-oil blends were investigated using the ASTM D6079 by the reciprocatory friction monitor. The effect of temperature variation on lubricity characteristics was also studied. The biodiesel-oil blends shows improvement in results as compared to diesel. Biodiesel is prone to oxidation due to availability of unsaturation in their moieties. The effects of oxidation on lubricity characteristics were also studied. It was also found that the operating conditions collectively affected the lubricity characteristics of tested feedstocks.

The experiments were performed to analyze the influence of apex angle on thermal and hydraulic characteristics of triangular duct for Reynolds number range from 2000 to 16,000. Four different triangular ducts of apex angle 30°, 60°, 90° and 110° were fabricated for the experimentation. The one side of the duct is roughened with dimple shaped roughness element. The both relative shortway length (s/e) and relative longway length (l/e) of dimple shaped roughened element was kept constant (i.e., 10) but relative roughness height (e/D) is varied from 0.016 to 0.038. Result shows that apex angle plays an important role in heat transfer. The experimental results are presented in a form of correlation for Nusselt number (Nu) and friction factor (f).

Fossil fuel consumption provides a negative impact on the human health and environment in parallel with the decreased availability of this valuable natural resource for the future generations to use as a source of chemical energy for all applications in energy, power, and propulsion. The diesel fuel consumption in the transport sector is higher than the gasoline in most developing countries for reasons of cost and economy. Biodiesel fuel offers a good replacement for diesel fuel in compression ignition (CI) diesel engines. Earlier investigations by the authors revealed that a blend of 70% amla seed oil biodiesel and 30% eucalyptus oil (AB70EU30) is the favorable alternative renewable fuel blend that can be used as a fuel in diesel engines. With any fuel, air/fuel mixing and mixture preparation impact efficiency, emissions, and performance in CI engines. Minor adjustments in engine parameters to improve air/fuel mixing and combustion are deployable approaches to achieve good performance with alternative fuel blends in CI engines. This paper provides the role of a minor modification to engine parameters (compression ratio, injection timing, and injection pressure) on improved performance using the above mixture of binary fuel blends (AB70EU30). The results showed that the use of AB70EU30 in modified engine resulted in higher brake thermal efficiency and lower brake specific fuel consumption compared to normal diesel for improved combustion that also resulted in very low tailpipe emissions.

This paper is about detecting two-wheeler riders without helmet with the help of machine learning and provide them with a user interface to pay challans. The proposed approach first captures the real time image of road traffic and then differentiates the two wheelers from other vehicles in the road. It then processes to check whether the rider and pillion rider are wearing helmet or not using OpenCV. If any one of the riders and pillion rider found not wearing the helmet, their vehicle number plate is processed using optical character recognition (OCR). After extracting the vehicle registration number, a challan will be generated against respective vehicle and all the details of the challan will be sent via E-mail and SMS to the concerned person. An user interface (an app and a website) will also be provided to pay their challans.

Rapidly depleting conventional fuel reserves had prompted research on alternative fuels for diesel engines as diesel is most widely used in public transportation all over the world. The environmental consequences of using diesel are also encouraging to shift our focus towards alternative fuels. The nitrogen oxides (NOx) and smoke are the significant emissions that must be controlled effectively as the NOx is responsible for forming the acid rain and ozone layer depletion, which is further associated with the adverse effects on the health of human being. It is clear from the previous literature that diesel can be partially replaced by compressed natural gas (CNG) in a compression ignition (CI) engine and able to reduce NOx and smoke emissions. In the this research, tests are performed on a variable speed CI engine operated under dual fuel mode (D + 10% CNG), (D + 15% CNG) and (D + 20% CNG) modes at various exhaust gas recirculation (EGR) rates, such as 5%, 10% and 15% for three different loading conditions. The results showed that in all loading conditions, BTE dropped by 1–2% and the BSFC decreased at higher load by 2–3% as compared to diesel. The HC and CO emissions are higher at low and high load conditions as compared to diesel. In dual fuel mode, the highest reduction in NOx and smoke is 21% and 18% respectively as compared to diesel. A model equation is developed using ANOVA analysis to optimize the emission results.

The force convective heat transfer in an equilateral triangular duct of different wall heat flux configurations was analysed for the laminar hydro-dynamically developed and thermally developing flow by the use of finite volume method. Unstructured meshing was generated by multi-block technique and set of governing equations were discretized using second-order accurate up-wind scheme and numerically solved by SIMPLE Algorithm. For ensuring accuracy, grid independence study was also done. Numerical methodology was verified by comparing results with previous work and predicted results showed good agreement with them (within error of ±5 %). The different combinations of constant heat flux boundary condition were analysed and their effect on heat transfer and fluid flow for different Reynolds number was also studied. The results of different combinations were compared with the case of force convective heat transfer in the equilateral triangular duct with constant heat flux on all three walls.

An experimental study has been carried out for the heat transfer and friction characteristics for arc shaped roughness element used in solar air heaters. Duct has an aspect ratio (W/H) of 11, relative roughness pitch (p/e) range of 4–16, relative roughness height (e/D) range of 0.027–0.045, Reynolds number (Re) range of 2200–22,000 and arc angle (α) was kept constant at 60°. The effects of Re, relative roughness pitch (p/e) and relative roughness height (e/D) on heat transfer and friction factor have been discussed. The results obtained for Nusselt number and friction factor has been compared with smooth solar air heater to see the enhancement in heat transfer and friction factor and it is found out that considerable enhancement takes place in case of heat transfer as well as in friction factor. Correlations were also developed for Nusselt number and friction factor. Thermo-hydraulic performance parameter is also calculated for the same.

Hydropower is considered as one of the most convenient and popular renewable energy technologies and its capacity is growing rapidly throughout the world. Its rapid deployment also comes up with various environmental issues which cannot be neglected at a glance. Previous studies had imposed questions about its sustainable nature and now it becomes important to think about the sustainability of hydropower projects so that the technology would grow effectively in future. This paper reviews the status of research on environmental assessment of hydropower projects. The factors which affect the environmental impacts associated with hydropower generation are also explored. It is found that environmental impact assessment of hydropower projects must be performed considering all aspects and factors which affects the environmental impacts associated with hydropower projects. Most of the previous studies are focused on the estimation of GHG emissions so it is necessary to give emphasis on other environmental impacts like acidification, land use, energy consumption etc. and also consider biomass decomposition in submerged land. In fact it is not worthy to predict the sustainability of hydropower projects without considering almost all biophysical impacts associated with them. The paper also compares large and small hydro considering all sustainability assessment factors. Small hydropower projects are considered as a good alternative to control the problems associated with large hydropower projects but still many studies found that so many issues are associated with small hydro as well which cannot be neglected completely.

The results obtained on wear assessment from a compression ignition (CI) engine fueled with a blend of 70% amla seed biodiesel (AB) and 30% eucalyptus oil (EU) on volume basis (called AB70EU30). The results showed stable engine operation and good operability of the engine-fuel system with the binary biodiesel fuel blend. The feasibility of this blend over a long-term endurance tests was explored. The specific assessment examination included the fate of cylinder head, pump plunger, injector nozzle, and piston crown, which affects the engine performance and engine life. The experimental results revealed better tribological performance characteristics with the binary fuel blend as compared to contemporary diesel fuel. No specific problem was encountered during the long-term endurance tests with the binary fuel blend using the modified engine parameters. The results show that the binary fuel mixture offers good potential for use as diesel fuel in CI engines while maintaining good performance and endurance.

This paper presents lubricating oil performance in a compression ignition (CI) engine fueled with a binary fuel blend of 70% aamla seed oil biodiesel and 30% eucalyptus oil (EU) on volume basis. This blended fuel was stable and congruent with engine-fuel system. Initially, the engine was operated with normal diesel fuel as per standard endurance test. The same endurance test was performed with the above binary biodiesel blended fuel in the engine under somewhat modified engine operational condition. The lubricating oil was examined at a specified interval to evaluate the impact of the fuel on lubricating oil properties. Quantification of various metal debris concentrations was carried out using inductive coupled plasma atomic emission spectroscopy. After experimentation, the lubricating oil samples were analyzed using analytical ferrography that showed lower wear debris concentrations from binary biodiesel blend than diesel fuel operated engine. The better lubricating property of binary biodiesel blended fuel resulted in lower wear and improved performance of engine parts. Relatively low wear and concentrations of all metal wear were found in the lubricating oil with binary biodiesel blended fuel engine revealed better performance of engine with this fuel blend. No technical problem was encountered during the long-term endurance tests with the binary biodiesel blended fuel under modified engine parameters.

The ribbed three-dimensional solar air heater (SAH) model is numerically investigated to estimate flow and heat transfer through it. The numerical analysis is based on finite volume approach, and the set of flow governing equations has been solved to determine the heat transfer and flow field through the SAH. For detailed analysis, rib chamfer height ratio (e′/e) and rib aspect ratio (e/w), two innovative parameters, have been created and considered along with the commonly used roughness parameter, i.e., relative roughness height, e/D. The parameters e′/e, e/w, and e/D are varied from 0.0 to 1, 0.1 to 1.5, and 0.18 to 0.043, respectively, but the value of P/e is kept constant for the entire investigation at 12. A good match is seen in Nusselt number (Nu) and friction factor (f) by comparing the predicted results with the experimental ones. With the variation of roughness parameters, distinguishable change in Nu and f is obtained. The highest value of thermohydraulic performance parameter (TPP) observed is 2.08 for P/e, e′/e, e/w, and e/D values of 12, 0.75, 1.5, and 0.043, respectively, at Re of 17,100. The developed generalized equation for Nu and f has shown acceptable percentage deviation under the studied range of parameters.

Turbulent flow heat transfer and friction penalty in triangular cross-sectional duct is studied in the present paper. The sharp corners of the duct are modified by converting it into circular shape. Five different models were designed and fabricated. Heat transfer through all the models was investigated and compared conventional triangular duct under similar conditions. The curvature radius of rounded corners for different models was kept constant (0.33 times the duct height). The numerical simulations were also performed and the obtained result validated with the experimental findings and close match observed between them. The velocity and temperature distribution is analyzed at particular location in the different models. Because of rounded corners, higher velocity is observed inside the duct (except corners) compared to conventional duct. Considerable increase in Nusselt number is seen in model-5, model-4, model-3, and model-2 by 191%, 41%, 19%, and 8% in comparison to model-1, respectively, at higher Reynolds number (i.e., 17,500). But, frictional penalty through the model-5, model-4, model-3, and model-2 increased by 287%, 54%, 18%, and 12%, respectively, in comparison to model-1 at lower Reynolds number (i.e., 3600).

With the advent of human population the need for energy consumption is growing every second. Due to these growing demands, energy production has reached to unprecedented levels. These in turn lead to great losses to environment in the form of various pollutants. With Kyoto protocol target obligations, quantification along with the reduction in greenhouse gas (GHG) emissions at the national level is an urgent requirement. Buildings are also one of the major sources of energy consumption and contributors of GHG emissions throughout their life cycle. Various studies based on life cycle assessment (LCA) have been carried out to assess the consumption of energy and environmental impacts allied with buildings. The present chapter deals with LCA of an academic building located at hilly terrain to quantify energy consumption along with GHG emissions. The obtained results are also compared with another LCA study to see the effects of location and climate change on energy consumption and GHG emissions.

In this study, a theoretical analysis of food processing (e.g., solar drying), worldwide cooking pattern, and cooking methods by using the solar energy has been reviewed. Solar food processing method is applied as direct absorption, air heater, and a combination of direct and indirect drying by solar radiation. Therefore, this process is one of the most accessible and hence the most widespread processing technologies. Traditional solar drying involves keeping products in the direct sunlight. Solar drying and cooking processes take place at different temperatures and timescales, and it depends on the nature of the food or substance. The amount of solar energy that reaches to the system and design parameters determines the performance of food processing and cooking systems. The time duration of drying and cooking depends on the temperature of heated air and environment. The temperature distributions, mass, and ingredient of food have an important role in the performance of dryers and cooker boxes. For a better understanding of the system parameters, the concept of solar food processing has been discussed thermodynamically. Energy saving by using solar systems has also been discussed.

With broad commutability of pollutants, air pollution is a complicated issue that intimidates directly to human health and our environment. Various indoor and outdoor air pollution comprises of regulated and unregulated emissions. Volatile organic compounds (VOCs) are one of them which are carcinogenic and lead to photochemical reactions. Emissions of VOCs are directly associated with large number of industrial processes, emission through transportation, and various indoor and outdoor sources. Due to deleterious effect of different VOCs emitted from transportation, chemical industrial plants and from indoor on the environment make their eviction mandatory or at least degrade them under the limit set by environmental norms. So, it has turned a burning topic to diminish air pollutants and set a norm for volatile emissions. This study focuses on the major sources of carbonyl and aromatic compounds in indoor and outdoor environment. Some remedial processes like photocatalytic oxidation, plasma decomposition, chemisorption, and catalytic oxidation have been described in this study through which decomposition of these contaminants can be achieved. This chapter contains a deep study on health effects from the carbonyl and aromatic compounds.

This paper presents a 2-D analytical model of surface potential for graded-channel-double-gate (GCDG) MOSFETs to discuss the benefits of incorporation of graded-channel in double-gate (DG) MOSFET. The 2-D analytical modeling is based upon the solution of Poisson's equations in channel region(s) exploring parabolic channel potential profile and excluding the effects of interface charges. The surface potential dependency on the variation of drain bias and doping is also discussed. The results obtained from the analytical model have been discussed to demonstrate the figure of merit of GCDG structure over Double Gate (DG) structure. To validate the analytical model results, the results obtained from analytical model have been compared with numerical simulation data obtained by 2-D device simulator, SILVACO ATLAS™.

This paper presents a 2-D analytical model of threshold voltage for nanoscale graded-channel-dual-material-double-gate (GCDMDG) MOSFETs to discuss the advantage of incorporation of channel engineering in dual-material-double-gate (DMDG) MOSFETs. The 2-D analytical modeling is based upon the solution of 2-D Poisson's equation in channel region(s) using parabolic channel profile with the help of different boundary conditions and excluding the effect of interface charges. The surface potential and threshold voltage dependency on various device parameters have been studied to support the advantages of GCDMDG MOSFETs over DMDG MOSFETs. To validate the analytical model results, numerical simulation data obtained from 2-D device simulators ATLAS™ SILVACO has been used.