The present study is aimed to discover and equate effect of daok biodiesel-diesel and daok biodiesel-antioxidant additive catechol-diesel blends on performance and emission characteristics (PEC) of a ...direct-injection diesel engine. Tests are conducted on daok biodiesel percentage of 10, 20, 40, 60 and 100% at variable engine loads and compression ratios (CRs) with 1500 rpm. At First, several pilot experiments are conducted among the doak biodiesel-diesel blends and found B20 as the optimum blend based on PEC of the engine. At rated speed of 1500 rpm, compression ratio is altered for the blend B20 and identified better engine PEC at CR 17.5. Then, 0.5, 1.5 and 2.5% of antioxidant catechol (CAT) additive is blended with B20 and investigated the PEC of the engine operating at CR17.5. Tested fuel blends indicated that the 2.5% of CAT in B20 blend produced better performance and yielded 6.45% rise in BTE, while 1.5% of CAT in B20 blend diminished CO and HC emissions by 26.08%, and 18.75% respectively as compared to B20 blend. It was also shown that adding CAT at a concentration of 0.5%–2.5% in a B20 biodiesel blend is sufficient for a considerable improvement in oxidation stability without affecting the physicochemical qualities. As a result, a low-cost CAT additive in daok biodiesel and diesel fuel can be used in direct injection diesel engines without requiring any additional engine configuration changes.
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•Effect of CAT-daok biodiesel blends on PEC of engine are studied.•CAT-daok biodiesel blend shown significant improvement in oxidation stability.•CO emissions decreased by 26.08% with the addition of CAT.•2.5% of CAT in B20 blend exhibited better engine performance with CR17.5.
In this paper, an experimental investigation carried out for estimating the overall energy exchange between the liquid desiccant and the ambient air is presented. The influence of air humidity ratio ...on the performance of the liquid desiccant dehumidification/regeneration system is studied in detail. A correlation for humidity ratio difference between the process air inlet and exit of the packed chamber in terms of known operating parameters is developed for both dehumidification and regeneration systems. A two–dimensional thermal model is proposed for predicting the performance of the adiabatic counter – flow liquid desiccant dehumidifier/regenerator. The proposed model is validated with the experimental data and found accurate. Influences of air humidity ratio, L/G ratio and Lewis number on the latent heat ratio of both the dehumidification and the regeneration systems are analysed. Using Derringer's desirability function method, for a given range of operating parameters, optimal inlet condition for the maximum humidity ratio difference between the inlet and the exit of the dehumidification/regeneration system is obtained.
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•Performance of dehumidification and regeneration systems are tested experimentally.•Developed correlations for humidity ratio difference along the packed chamber.•Analysed transfer process at the interface of water and air using a thermal model.•Investigated the effect of Lewis number (Le) on evaporation and condensation rates.•Predicted optimum conditions to obtain a maximum specific humidity difference.
In this work, the waste heat/solar heat-driven membrane-based liquid desiccant regenerator performance, as well as desalinated water extraction rate, are predicted and analyzed by developing a ...thermal model and KNN–ML tool. In the membrane-based liquid desiccant regenerator, water is used as a working fluid instead of scavenging air for desalinated water extraction purpose. The proposed thermal model and KNN-ML tool are validated with the literature data and found in good agreement. Optimal inlet conditions were determined for the given operating range using the thermal model and KNN–ML tool. With vapor flux and energy exchange as the performance indicators, the water extraction rate and thermal performance of the membrane-based liquid desiccant regenerator are predicted for the optimal inlet condition using the KNN-ML tool. Also, the heat and mass transfer characteristics such as Lewis number and NTUm across the membrane in the liquid desiccant regenerator are assessed using the developed thermal model. Further, for the optimal inlet conditions, utilizing waste heat from thermal power plants (Method–I) and solar energy from solar heater (Method–II), the thermal performance and water extraction rate across the membrane in the liquid desiccant regenerator are assessed based on the developed thermal model.
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•Strategy for integrating renewable sources with desiccant regenerator is proposed.•Developed a thermal model to assess the membrane regenerator performance•Introduced the KNN based machine learning tool for system performance prediction•Water extraction rate from waste heat/solar driven membrane regenerator is studied.•Transfer characteristics at membrane interface is analyzed for optimal condition.
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•Development of ANFIS–AI tool for design and performance optimization of DCHE.•Predicted optimal design and inlet condition of DCHE using ANFIS–AI tool.•Investigated the influence of ...design and inlet parameters on DCHE performance.•Assessed adsorption kinetics of DCHE using dynamic model based on Laplace transform.•Examined the interactive effect of Lewis and Stanton numbers on performance of DCHE.
To improve indoor air quality, enhance the energy exchange capabilities and minimize the spread of microbial pollutants, desiccant coated heat exchanger seems a promising alternative to conventional heat exchangers such as rotary wheel and adsorber beds. Thus, precise prediction of the design and performance characteristics of desiccant coated heat exchanger is vital for improving the overall air conditioning system performance. Therefore, in the present investigation, an adaptive neuro-fuzzy inference system with artificial neural network fuzzy logic has been implemented to predict the exit parameters of desiccant coated heat exchangers. The advantage of an adaptive neuro-fuzzy inference system is its structure that combines the neural network's learning ability, excellent information representation capability of fuzzy logic, and adaptive algorithm. Silica gel is taken as the coated desiccant. The impact of inlet and design parameters on the performance characteristics of desiccant coated heat exchanger during dehumidification has been evaluated using the artificial intelligence adaptive neuro-fuzzy inference system. Also, the optimal design/inlet conditions for the given operating and design parametric range are obtained. For the obtained optimal conditions, the maximum valves of dehumidification capacity, vapor pressure difference ratio, and sensible energy load ratio are 2.01 kg/h, 0.84, and 0.135, respectively. Further, a dynamic model based on the Laplace transform is developed to assess desiccant coated heat exchangers' adsorption kinetics and thermal effects. Moreover, the interactive effect of Lewis number and Stanton number on the performance parameters has been examined judiciously. Adsorption kinetics of silica gel shows that the water adsorped per mass desiccant is about 0.1129 g/g at the end of sorption time.
It is quite interesting that when a venomous snake bites a person and the victim does not suffer from any signs or symptoms of envenomation. A good percentage of venomous snake bites in humans do ...occur without venom injection. This phenomenon is termed as “Dry” bite in clinical medicine. Though this was not very uncommon in toxicological practice but, our awareness of this problem has increased. In this article an effort has been made to provide an insight into the incidence, pathophysiology and patho-mechanics of this unique medical enigma.
•“Dry bite” is a definitive clinical entity in venomous snake bites.•Incidence varies with species of venomous snakes, geographical area.•Possible explanations discussed in this review article.
Microplastic pellets (MPPs) are ubiquitous contaminants, recognised as a serious threat to the biota in coastal, estuarine and marine environment. The distribution, abundance, weathering and chemical ...characteristics of MPPs on the beaches of Goa, and their transport to the coast during the southwest (SW) monsoon are discussed in this paper. MPP samples collected from six sandy beaches were categorised based on colour and polymer types using Stereoscope microscope and FTIR-ATR spectroscopy, respectively. White colour MPPs were the most abundant, and Polyethylene (PE) and Polypropylene (PP) were the dominant polymer types of MPPs deposited on all the beaches. Carbonyl index values showed that MPPs collected in June 2015 (representing SW monsoon) were ‘new’, whereas the MPPs collected in January 2015 were ‘aged’, showing that MPPs are arriving at Goa coast only during SW monsoon due to conducive hydrodynamic conditions. Characteristics of MPPs suggest that they could be originated primarily from ocean-based sources. The winds and surface currents during SW monsoon are the driving forces for the transportation and deposition of MPPs on the Goa beaches. The results of this study will be useful to the National ‘Clean India’ program for effective plastic debris removal management.
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•We investigated the spatial and seasonal variations of MPPs at 6 beaches of Goa.•White MPPs with PE and PP polymer types are abundant in all beaches.•Weathering of MPPs during the NE is higher than the SW monsoon.•Sources of MPPs on beaches of Goa coast probably ocean-based.•SW monsoon winds and currents are the driving forces for deposition of MPPs.
Background and Aims: Ultrasound-guided subclavian vein cannulation has two approaches: supraclavicular and infraclavicular. The aim of this study was to compare the ease of cannulation by recording ...the puncture time of the subclavian vein with the two approaches in adult patients.
Material and Methods: This study was approved by our institutional ethics committee, and a written informed consent was obtained from the patients. This prospective randomized trial recruited patients aged 18 to 80 years with definite indications of subclavian vein cannulation. Real-time in-plane ultrasound-guided technique was used, and the subclavian vein was punctured at the junction of the brachiocephalic and IJV in supraclavicular approach (SC) and in oblique axis below the border of the clavicle in infraclavicular approach (IC).
Results: A total of 96 patients were randomly allocated equally into two groups of 48 each, but only 45 patients in each group could be successfully cannulated. Median puncture times were comparable; 15 (9-39) s in SC and 21 (5-80) s in IC group. The first attempt success rate was 82.2% and 62.2%, and the mean total access time was 99.11 ± 34.66 s and 103.44 ± 50.27 s in SC and IC approaches, respectively and were comparable. The attempts of needle puncture were significantly higher in IC approach (1.40 ± 0.54 vs 1.20 ± 0.46 in SC approach; P = 0.04). The complication rates were comparable and less than 5%.
Conclusion: Ease of cannulation of the subclavian vein using ultrasound-guided supraclavicular and infraclavicular approach is comparable as no statistically significant difference is noted in the puncture time and first-attempt success rate. The increased number of needle punctures reported in our study with the IC approach did not translate to an increased complication rate.
•Simple analytical model for cross-flow cooling tower is proposed.•Predicted performances of the cooling tower match well with the experimental data.•Analyzed the performances of the cooling tower ...for humid subtropical climate.•Effects of various operating parameters on cooling tower performances are studied.•Developed model provides useful guidelines for the preliminary design purposes.
Wet cooling tower is one of the key components of large scale water cooled air conditioning plants, whose efficiency influence the COP of the plant to a large extent. This study proposes a simple analytical model for calculating the amount of water taken up by the ambient air in a cross-flow wet cooling tower. An expression is derived using the condenser and the cooling tower effectiveness, to estimate the water evaporation loss of the cooling tower in terms of known inlet parameters. The model predictions are compared with experimental data and good agreement is observed. Also, good agreement exists between the predictions from the analytical model and experimental findings available in the literature. The influence of operating parameters such as water inlet temperature, relative humidity, air dry bulb temperature and specific humidity on the evaporation loss, heat load and tower efficiency are investigated for a humid subtropical climate. The results show that the above listed operating parameters, except air dry bulb temperature have a significant impact on the performance of the cooling tower. Furthermore, influences of refrigerant inlet temperature, thermal effectiveness of the cooling tower and condenser effectiveness on the performance of the wet cooling tower are also investigated.
Intensive tillage coupled with imbalanced nutrient management in maize–wheat systems in low-carbon calcareous soils often results in poor productivity vis-à-vis degradation in soil health. ...Conservation tillage viz. permanent bed planting (PB) and zero tillage (ZT)/direct seeding with residue retention coupled with precision nutrient management might improve soil properties and yield of crops. Concerning this, a long-term experiment was conducted from 2014–2015 to 2020–2021 with a maize–wheat cropping system at TCA, Dholi farm of RPCAU, Pusa. Treatments consisted of three main plots of different tillage practices, viz. PB, ZT, and conventional tillage (CT) and three sub-plots of nutrient management options, viz. farmers’ fertilization practice (FFP), site-specific nutrient management with Nutrient Expert® (NE) software, and GreenSeeker (GS) based nitrogen-management. From this study, it was observed that both the PB and ZT resulted in about 31–33% and 43–45% improvement in SOC and water-soluble aggregates (WSA), respectively, comparing them under CT. These two conservation tillage practices also improved the other soil bio-chemical properties. Better soil properties under PB and ZT helped in the improvement of system yield by about 13–18% comparing yield under CT. Moreover, both these tillage practices showed an additional net return of USD 330–USD 400 over CT. PB was found a bit better over ZT concerning soil properties, yield, and economics. Comparing nutrient management options, precision nutrition using NE and GS showed significant improvement in the soil bio-chemical parameters, yield, and economics of the cropping system over FFP. SSNM using NE showed slightly better results than GS. Thus, from this long-term study, it can be concluded that the permanent bed system with residue retention and precision nutrition using Nutrient Expert® software are the best options concerning tillage and nutrient management, respectively, for improvement of the soil properties of problematic calcareous soils, thereby, enhancing the yield and economics of the maize–wheat cropping system.
The current study concentrates on chemical kinetics, thermodynamic, and overall mass transfer studies on production of biodiesel from waste cooking sunflower oil in transesterification reaction using ...bentonite-supported sodium methoxide catalyst. The kinetics and thermodynamics analysis of biodiesel from waste cooking sunflower oil was studied at three different temperatures, namely, as 50, 55, and 60 °C using bentonite-supported sodium methoxide catalyst at optimized conditions of methanol-to-oil molar ratio of 12:1 and reaction time of 70 min. It was found that transesterification of waste cooking sunflower oil follows the first-order reaction. The calculated activation energy and pre-exponential factor were found to be 40.98 kJ mol
−1
and 1.4 × 10
5
, respectively. The positive values of Gibbs free energy (∆
G
= 89.66 kJ mol
−1
), enthalpy (∆
H
= 38.05 kJ mol
−1
), and negative entropy (∆
S
= − 0.15 kJ K
−1
mol
−1
) values revealed that the transesterification process is non-spontaneous and endothermic in nature. The reaction rate is a function of two resistances: the surface chemical reaction on the catalyst surface and the mass transfer of triglycerides to the catalyst. The overall calculated parameters of triglyceride volumetric mass transfer coefficient,
k
mt,TG
is 1.18 × 10
3
min
−1
, and effective pseudo-first-order reaction rate constant,
k
, is 0.0525 kJ mol
−1
min. The used kinetic model accurately represents the entire transesterification mechanism, involving triglyceride conversion to fatty acid methyl ester (FAME) and reaction-controlled on the catalyst. It is observed that the overall volumetric mass transfer depends mainly on the triglyceride conversion rate.
