scholarly journals Performance Analysis of Flat and Rippled Wick-Inverted V-Type Solar Still Integrated with Drip System in Kerala Climatic Conditions

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
T. Namshad ◽  
K. R. Ayush ◽  
K. C. Salih ◽  
Athul James ◽  
Suficker Ahammed ◽  
...  
Keyword(s):  
Internal Heat ◽  
Working Hours ◽  
Climatic Conditions ◽  
Experimental Investigations ◽  
Solar Still ◽  
The Mean ◽  
Experimental Values ◽  
College Of Engineering ◽  
Desalination Plants ◽  
Internal Heat Transfer

Thermal aspect of solar energy is widely used in the desalination plants. Experimental investigation and mathematical modeling of inverted V-type solar still integrated with drip system are presented in this paper. The experiment is performed in the Kerala climatic conditions (10.8439°N, 76.0328°E), March 2012 at M E S College of Engineering, Kuttippuram. A two segment still of 2 m2 is constructed. Experimental investigations on productivity and internal heat transfer are analyzed. The results indicate that the mean standard deviations between theoretical and experimental values are less than 7% (temperature of rippled wick), 8% (temperature of glass in rippled system), 11% (temperature of flat wick), and 7% (temperature of glass in flat system), an average for the working hours of the day.

scholarly journals Analytical thermal modeling of double slope solar still by using inner glass cover temperature

2008 ◽  
Vol 12 (3) ◽  
pp. 139-152 ◽  
Author(s):  
Kumar Shukla ◽  
Ajeet Rai
Keyword(s):  
Internal Heat ◽  
Climatic Conditions ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Glass Cover ◽  
Solar Distillation ◽  
Indian Climatic ◽  
C And N ◽  
Internal Heat Transfer

In this paper, expressions for water and glass temperatures, hourly yield and instantaneous efficiency for double slope solar distillation systems have been derived analytically. The analysis is based on the basic energy balance for the systems. A thermal model has been developed to predict the performance of the still based on both, the inner and the outer glass temperatures of the solar still. In the present work two sets of values of C and n of internal heat and mass transfer coefficients, obtained from the experimental data under Indian climatic conditions, have been used. It is concluded that (1) there is a significant effect of operating temperature range on the internal heat transfer coefficients and (2) by considering the inner glass cover temperature there is reasonable agreement between the experimental and predicted theoretical results.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

scholarly journals Retinal vascular findings in patients with COVID-19

2021 ◽  
Vol 13 ◽  
pp. 251584142110304
Author(s):  
Emre Aydemir ◽  
Alper Halil Bayat ◽  
Burak Ören ◽  
Halil Ibrahim Atesoglu ◽  
Yasin Şakir Göker ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Fundus Photography ◽  
Control Group ◽  
Fundus Fluorescein Angiography ◽  
University Of Wisconsin ◽  
Retinal Vascular Caliber ◽  
Retinal Artery ◽  
The Mean ◽  
And Gender ◽  
College Of Engineering

Purpose: The purpose of this study was to compare the retinal vascular caliber of COVID-19 patients with that of healthy subjects. Methods: This was a prospective case–control study. Forty-six patients who had COVID-19 were successfully treated, and 38 age- and gender-matched healthy subjects were enrolled in this study. Fundus photography was taken using fundus fluorescein angiography (FA; Visucam 500; Carl Zeiss Meditec, Jena, Germany). Retinal vascular caliber was analyzed with IVAN, a semi-automated retinal vascular analyzer (Nicole J. Ferrier, College of Engineering, Fundus Photography Reading Center, University of Wisconsin, Madison, WI, USA). Central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery–vein ratio (AVR) were compared between groups. Results: The mean age was 37.8 ± 9.5 years in the COVID-19 group ( n = 46) and 40 ± 8 years in the control group ( n = 38) ( p = 0.45). The mean CRAE was 181.56 ± 6.40 in the COVID-19 group and 171.29 ± 15.06 in the control group ( p = 0.006). The mean CRVE was 226.34 ± 23.83 in the COVID-19 group and 210.94 ± 22.22 in the control group ( p = 0.044). AVR was 0.81 ± 0.09 in the COVID-19 group and 0.82 ± 0.13 in the control group ( p = 0.712). Conclusion: Patients who had COVID-19 have vasodilation in the retinal vascular structure after recovery. As they may be at risk of retinal vascular disease, COVID-19 patients must be followed after recovery.

Infrared spectra, rotational correlation functions, and intermolecular mean squared torques in compressed gaseous methane

1968 ◽  
Vol 46 (11) ◽  
pp. 1331-1340 ◽  
Author(s):  
R. L. Armstrong ◽  
S. M. Blumenfeld ◽  
C. G. Gray
Keyword(s):  
Correlation Functions ◽  
Theoretical Calculations ◽  
Dominant Contribution ◽  
Dispersion Interactions ◽  
Fundamental Vibration ◽  
Order Of Magnitude ◽  
The Mean ◽  
Vibration Rotation ◽  
Experimental Values ◽  
Rotational Correlation

Extensive measurements of the methane ν3 and ν4 fundamental vibration–rotation bands in CH4–He mixtures and the ν3 band in CH4–He, CH4–N2, and CD4–He mixtures have been carried out in infrared absorption at 295 °K to pressures of 3000 atm. Some profiles of the ν3 band in CH4–Ar mixtures and in pure CH4 have also been obtained. Rotational correlation functions, band moments, and intermolecular mean squared torques have been determined from the ν3 band profiles. Theoretical calculations of the mean squared torque due to anisotropic multipolar, induction and dispersion interactions have been carried out. The theoretical and experimental torques are in order-of-magnitude agreement for the CH4–N2 and CH4–CH4 systems; for CH4–He, CD4–He, and CH4–Ar the theoretical values are two to three orders of magnitude too small to account for the experimental values, indicating that in these cases the dominant contribution to the torques is given by the anisotropic overlap forces.

Seasonal Influence on Milk Production Performance in SDCMPUL in Tamil Nadu

2021 ◽  
Keyword(s):  
Milk Production ◽  
Tamil Nadu ◽  
Seasonal Fluctuation ◽  
Secondary Data ◽  
Climatic Conditions ◽  
Production Performance ◽  
Reproduction Traits ◽  
Dairy Animals ◽  
The Mean ◽  
Spss Software

Dairy farming is vulnerable to seasonal variable factors such as temperature, cold climatic conditions, and rainfall. These affect the production and reproduction traits of dairy animals. Seasonal variability also affects the quantity of consumption and marketing of milk considerably. The study aimed to assess the seasonal fluctuation in milk production in Sivagangai District Cooperative Milk Producer Union Limited (SDCMPUL), Tamil Nadu. The study used secondary data. The milk production data were collected from SDCMPUL, Karaikudi, Tamil Nadu. The data covered the period from 2001-02 to 2020-21. The study used descriptive statistics, CAGR, and paired ‘t-test to determine the variation of milk production according to seasonal changes. The MS office - Excel software and SPSS software were used to analyse the data. The results revealed that the mean milk production of the lean and flush season was 2.46 and 2.30 lakh liters, and the CAGR of milk production in SDCMPUL, Tamil Nadu, during the period 2001-02 to 2020-21 was 5.65 percent, and it was 5.23 percent in lean season and 6.11 percent in the flush season while the growth rate of milk production during the lean and flush season was positive and was significant statistically. It was found that the quantity of milk production was higher in the lean season than a flush season; however, the variability of milk production was more in the flush season than in the lean season.

scholarly journals Effect on nitrate concentration in stream water of agricultural practices in small catchments in Brittany: I. Annual nitrogen budgets

2002 ◽  
Vol 6 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. Ruiz ◽  
S. Abiven ◽  
P. Durand ◽  
C. Martin ◽  
F. Vertès ◽  
...  
Keyword(s):  
Land Use ◽  
Nitrate Concentration ◽  
Stream Water ◽  
Agricultural Practices ◽  
Climatic Conditions ◽  
Nitrogen Budgets ◽  
Annual Variations ◽  
Nitrate Concentrations ◽  
The Mean ◽  
Small Catchments

Abstract. The hydrological and biogeochemical monitoring of catchments has become a common approach for studying the effect of the evolution of agricultural practices on water resources. In numerous studies, the catchment is used as a "mega-lysimeter" to calculate annual input-output budgets. However, the literature reflects two opposite interpretations of the trends of nitrate concentration in streamwater. For some authors, essentially in applied studies, the mean residence time of leached nitrate in shallow groundwater systems is much less than one year and river loads reflect annual land use while for others, nitrate is essentially transport limited, independent of soil nitrate supply in the short term and annual variations reflect changes in climatic conditions. This study tests the effect of agricultural land-use changes on inter-annual nitrate trends on stream water of six small adjacent catchments from 0.10 to 0.57 km2 in area, on granite bedrock, at Kerbernez, in Western Brittany (France). Nitrate concentrations and loads in streamwater have been monitored for nine years (1992 to 2000) at the outlet of the catchments. An extensive survey of agricultural practices from 1993 to 1999 allowed assessment of the nitrogen available for leaching through nitrogen budgets. For such small catchments, year-to-year variations of nitrate leaching can be very important, even when considering the 'memory effect' of soil, while nitrate concentrations in streamwater appear relatively steady. No correlation was found between the calculated mean nitrate concentration of drainage water and the mean annual concentration in streams, which can even exhibit opposite trends in inter-annual variations. The climatic conditions do not affect the mean concentration in streamwater significantly. These results suggest that groundwater plays an important role in the control of streamwater nitrate concentration. Keywords: nitrate, diffuse pollution, agricultural catchment, nitrogen budget, leaching, Kerbernez catchments

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