Assessment of alumina nano fluid as a coolant in double pipe gas cooler for trans-critical CO2 refrigeration cycle

In this study, the performance of an alumina nanofluid cooled double pipe gas cooler fortrans-critical C02 refrigeration cycle is theoretically compared to that of water cooled gas cooler. Equal pumping power comparison criterion is adopted besides conventional equal Reynolds number comparison base. Nanofluid is loaded with 0.5%, 1.5% and 2.5% of particle volume fraction under turbulent flow conditions. Drastic variation of thermal and transport properties of CO2 in the vicinity of pseudo criticai temperature is taken care of by employing an appropriate discretization technique. Effect of gas cooler pressure, Reynolds number, pumping power and nanoparticle volume fraction on COP of refrigeration system, gas cooler overall conductance, effectiveness and its capacity has been studied. Results indicate that at equal Reynolds number comparison, performance for alumina nanofluid cooled system is better than that of water cooled system. On the other hand, at equal pumping power comparison basis, the performance of water cooled system is superior. Even at equal mass flow rate comparison criterion, the performance of nanofluid cooled system degrades with increase in particle volume fraction. This study is expected to help to assess the nano fluid as a coolant before expensive experimentation

Stereoselective Ag-Catalyzed 1,3-Dipolar Cycloaddition of Activated Trifluoromethyl-Substituted Azomethine Ylides

This is the peer reviewed version of the following article: Chemistry – A European Journal 22.14 (2016): 4952 - 4959, which has been published in final form at http://doi.org/10.1002/chem.201504869. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsA silver-catalyzed 1,3-dipolar cycloaddition of fluorinated azomethine ylides and activated olefins is reported. The reaction offers a straightforward and atom-economical procedure for the preparation of fluorinated pyrrolidines. Broad scope and high levels of diastereoselectivity have been achieved simply by using AgOAc/PPh3as the catalyst system. The high efficiency of the cycloaddition relies on the presence of a metal-coordinating group on the imine moiety, such as an ester or heteroaryl group. The asymmetric version of the cycloaddition has been developed by using Taniaphos as a chiral ligandFinancial support of this work by the Ministerio de Economía y Competitividad (MINECO, CTQ2012-35790) is gratefully acknowledge

Predictability of STOP-Bang Questionnaire and Epworth Sleepiness Scale in Identifying Obstructive Sleep Apnoea against Polysomnography: A Cross-sectional Study

Introduction: Rising morbidty resulting from Obstructive Sleep Apnoea (OSA) is an emerging public health concern. The estimated prevalence of OSA in India has been investigated. STOP-Bang and Epworth Sleepiness Scale (ESS) have proven beneficial in identifying sleep breathing disorder. Validity of these questionnaire has been verified against polysomnography in many studies. Aim: To assess the predictive ability of STOP-Bang questionnaire and ESS in identifying OSA and comparing their efficacy with polysomnography. Materials and Methods: The cross-sectional study was conducted in the Department of Respiratory Medicine, Government Medical College, Kota, Rajasthan, India, from January 2020 to June 2021, among 100 patients with symptoms of OSA. The STOP-Bang questionnaires were administered to the patients, and scoring was done, followed by overnight attended polysomnography. The normality of data was tested by Shapiro Wilk’s test. The values obtained were statistically analysed and to compare the parameters between groups and with in groups for normal data parametric test One-way Analysis of Variance (ANOVA) followed by Tukey’s HSD test, for intragroup Paired t-test. Results: Mean age of the study population was 49.46±6.523 years, 79 were males and 21 females. Total, 79% of the subjects were males, and 21% of the study subjects were females. Among the 100, 65% had OSA as per polysomnography. STOP-Bang questionnaire had a higher sensitivity as compared to ESS in predicting OSA (75.38% for STOP-Bang and 72.31% for ESS). Conversely, the specificity of ESS (82.8%) was found to be greater than STOP-Bang (45.71%). Similar results were obtained for positive predictive value, in which ESS scored 88.6% while STOP-Bang scored 50%. For negative predictive values, ESS again scored higher (65%) than STOP-Bang (61.7%). Similarly, the Likelihood Ratio for a positive result (LR+) of ESS was greater than STOP-Bang (4.2 and 1.3 respectively). The STOP-Bang questionnaire, however, had higher Likelihood Ratio for a negative test (LR-) as compared to ESS (0.5 and 0.3 respectively). Conclusion: Polysomnography is the gold standard to diagnose OSA. For screening OSA, patients with symptoms of sleep disordered breathing, this study found that STOP-Bang questionnaire is better in identifying OSA as compared to ESS

An Eco-Friendly Synthesis Approach for Enhanced Photocatalytic and Antibacterial Properties of Copper Oxide Nanoparticles Using Coelastrella terrestris Algal Extract

Manisha Khandelwal,1 Sunita Choudhary,2 Harish,2 Ashok Kumawat,3 Kamakhya Prakash Misra,3 Yogeshwari Vyas,1 Bhavya Singh,4 Devendra Singh Rathore,4 Kanchan Soni,3 Ashima Bagaria,3 Rama Kanwar Khangarot1 1Department of Chemistry, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India; 2Department of Botany, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India; 3Department of Physics, School of Basic Sciences, Manipal University Jaipur, Jaipur, Rajasthan, 303007, India; 4Department of Environmental Sciences, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, IndiaCorrespondence: Rama Kanwar Khangarot, Department of Chemistry, University College of Science, Mohanlal Sukhadia University, Udaipur, Rajasthan, 313001, India, Email [email protected]: In the current scenario, the synthesis of nanoparticles (NPs) using environmentally benign methods has gained significant attention due to their facile processes, cost-effectiveness, and eco-friendly nature.Methods: In the present study, copper oxide nanoparticles (CuO NPs) were synthesized using aqueous extract of Coelastrella terrestris algae as a reducing, stabilizing, and capping agent. The synthesized CuO NPs were characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and field emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS).Results: XRD investigation revealed that the biosynthesized CuO NPs were nanocrystalline with high-phase purity and size in the range of 4.26 nm to 28.51 nm. FTIR spectra confirmed the existence of secondary metabolites on the surface of the synthesized CuO NPs, with characteristic Cu–O vibrations being identified around 600 cm− 1, 496 cm− 1, and 440 cm− 1. The FE-SEM images predicted that the enhancement of the algal extract amount converted the flattened rice-like structures of CuO NPs into flower petal-like structures. Furthermore, the degradation ability of biosynthesized CuO NPs was investigated against Amido black 10B (AB10B) dye. The results displayed that the optimal degradation efficacy of AB10B dye was 94.19%, obtained at 6 pH, 50 ppm concentration of dye, and 0.05 g dosage of CuO NPs in 90 min with a pseudo-first-order rate constant of 0.0296 min− 1. The CuO-1 NPs synthesized through algae exhibited notable antibacterial efficacy against S. aureus with a zone of inhibition (ZOI) of 22 mm and against P. aeruginosa with a ZOI of 17 mm.Conclusion: Based on the findings of this study, it can be concluded that utilizing Coelastrella terrestris algae for the synthesis of CuO NPs presents a promising solution for addressing environmental contamination. Keywords: green synthesis, CuO NPs, photocatalysis, antibacterial activity, wastewater treatmen

Toxicity evaluation of metal plating wastewater employing the Microtox® assay: A comparison with cladocerans and fish

The relative sensitivity of the Microtox assay is closely related to the type of toxicant, and hence its utility in biomonitoring effluents is better evaluated on a case-by-case basis. The Microtox® assay, employing the marine bacterium Vibrio fischeri , was evaluated for its applicability in monitoring metal plating wastewater for toxicity. The results of the Microtox assay after 5, 15, and 30 min of exposure, were compared with data obtained from conventional whole effluent toxicity testing (WET) methods that employed Daphnia magna , Ceriodaphnia dubia , and the fathead minnow ( Pimephales promelas ). The Microtox assay produced notably comparable EC50 values to the LC50 values of the acute fathead minnow toxicity test (<0.5 order of difference). The Spearman's rank correlation analyses showed that the bacterial assay, regardless of exposure duration, correlated better with the acute fish than the daphnid results ( p <0.05). These observations were consistent to other studies conducted with inorganic contaminants. The relative sensitivity of the 30-min Microtox assay was within the range of the two frequently used acute daphnid/fish toxicity tests. In conclusion, the Microtox assay correlated well with the acute fathead minnow data and is well suited for toxicity monitoring for these types of industrial wastes. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 136–141, 2001Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35240/1/1017_ftp.pd