A Tubeless V-Trough Solar Concentrator

1986 ◽  
Vol 10 (3) ◽  
pp. 135-140
Author(s):  
M. Issa Abdulhadi
Keyword(s):  
Experimental Investigation ◽  
Energy Balance ◽  
Analytical Approach ◽  
Mathematical Expression ◽  
Time Interval ◽  
Solar Concentrator ◽  
Late Afternoon ◽  
Heating And Cooling ◽  
Reliable Source ◽  
Good Agreement

An analytical, experimental investigation of the thermal performance of a tubeless V-trough concentrator has been carried out. Considering the energy balance on the receiver plate, a mathematical expression is developed from which the receiver plate mean temperature can be evaluated for each time interval. The good agreement between the experimental results and the analytical predictions indicate that the construction of a tubeless absorber panel might be valuable and the analytical approach might have the potential for further extensions. It has been found, according to the expermental investigation, that the fluid outlet temperatures vary between 69°C and 91 °C from 10:30 a.m. on up to the termination of operation in the late afternoon. This qualifies the V-trough to be a reliable source for providing temperatures in this range that can be utilized in heating and cooling applications.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

scholarly journals Experimental Investigation of a Novel Absorptive/Reflective Solar Concentrator: A Thermal Analysis

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1281 ◽  
Author(s):  
Alok Dayanand ◽  
Muhsin Aykapadathu ◽  
Nazmi Sellami ◽  
Mehdi Nazarinia
Keyword(s):  
Experimental Investigation ◽  
Cooling System ◽  
Electrical Performance ◽  
Solar Concentrator ◽  
Cell Temperature ◽  
Compound Parabolic Concentrator ◽  
Pv Cell ◽  
Overall Efficiency ◽  
First Time ◽  
Absorber Surface

This paper presents the experimental investigation of a novel cross-compound parabolic concentrator (CCPC). For the first time, a CCPC module was designed to simultaneously work as an electricity generator and collect the thermal energy present in the module which is generated due to the incident irradiation. This CCPC module consists of two regions: an absorber surface atop the rig and a reflective region below that to reflect the irradiation onto the photovoltaic (PV) cell, coupled together to form an absorptive/reflective CCPC (AR-CCPC) module. A major issue in the use of PV cells is the decrease in electrical conversion efficiency with the increase in cell temperature. This module employs an active cooling system to decrease the PV cell temperature, optimizing the electrical performance and absorbing the heat generated within the module. This system was found to have an overall efficiency of 63%, which comprises the summation of the electrical and thermal efficiency posed by the AR-CCPC module.

Experimental Investigation on the Effect of Arm Length on Accuracy of Torque Wrench

2016 ◽  
Vol 853 ◽  
pp. 216-220 ◽  
Author(s):  
You Gang Peng ◽  
Yong Wang
Keyword(s):  
Experimental Investigation ◽  
Structural Design ◽  
Bending Moment ◽  
Theoretical Solution ◽  
Calibration Laboratory ◽  
Moment Measurement ◽  
Torque Wrench ◽  
Actual Use ◽  
Good Agreement

Experiments were carried out to investigate the effect of arm length on the accuracy of two typical conventional torque wrenches, namely, setting type torque wrench (STW) and indicating type torque wrench (ITW). The experiment results demonstrate that the measurement values of STW rises rapidly with decreasing arm length while measured torque of ITW shows irrelevant to arm length. Theoretical solution with respect to STW shows quite good agreement with experiment results. Irrelevance of arm length regard to ITW may be attributable to compensation of bending moment measurement due to proper arrangement of circuit and structural design. In order to conduct a proper assessment at a calibration laboratory or ensure its reliability with reference to actual use conditions, a torque wrench should be used by a customer at the loading point as recommended.

Analytical approach for transient photoconductivity in undoped a-Si:H

1995 ◽  
Vol 377 ◽  
Author(s):  
M. Goerlitzer ◽  
P. Pipoz ◽  
H. Beck ◽  
N. Wyrsch ◽  
A. V. Shah
Keyword(s):  
Steady State ◽  
Theoretical Model ◽  
Analytical Approach ◽  
Room Temperature ◽  
Free Electrons ◽  
Recombination Time ◽  
Sample Quality ◽  
Transient Photoconductivity ◽  
Light Intensities ◽  
Good Agreement

ABSTRACTTransient photoconductive response of undoped a-Si:H has been studied; the changes were analysed between two slightly different steady-state illumination conditions, at room temperature. A theoretical model is developed to describe transient photoconductivity; it yields good agreement with the measured curves for a whole range of light intensities. Numerical evaluations allows one to extract the recombination time of electrons. Comparison with steady-state photoconductivity yields a band mobility of free electrons between 0.1 and 6 cm2V−1s−1, depending upon sample quality.

scholarly journals New Results on the Motions of Asteroids in Resonances

1992 ◽  
Vol 152 ◽  
pp. 145-152 ◽  
Author(s):  
R. Dvorak
Keyword(s):  
Initial Conditions ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Close Approach ◽  
Integration Time ◽  
Time Interval ◽  
Time Intervals ◽  
3 Dimensional ◽  
Special Cases ◽  
Good Agreement

In this article we present a numerical study of the motion of asteroids in the 2:1 and 3:1 resonance with Jupiter. We integrated the equations of motion of the elliptic restricted 3-body problem for a great number of initial conditions within this 2 resonances for a time interval of 104 periods and for special cases even longer (which corresponds in the the Sun-Jupiter system to time intervals up to 106 years). We present our results in the form of 3-dimensional diagrams (initial a versus initial e, and in the z-axes the highest value of the eccentricity during the whole integration time). In the 3:1 resonance an eccentricity higher than 0.3 can lead to a close approach to Mars and hence to an escape from the resonance. Asteroids in the 2:1 resonance with Jupiter with eccentricities higher than 0.5 suffer from possible close approaches to Jupiter itself and then again this leads in general to an escape from the resonance. In both resonances we found possible regions of escape (chaotic regions), but only for initial eccentricities e > 0.15. The comparison with recent results show quite a good agreement for the structure of the 3:1 resonance. For motions in the 2:1 resonance our numeric results are in contradiction to others: high eccentric orbits are also found which may lead to escapes and consequently to a depletion of this resonant regions.

scholarly journals Multiscale Analysis of DInSAR Measurements for Multi-Source Investigation at Uturuncu Volcano (Bolivia)

2019 ◽  
Vol 11 (6) ◽  
pp. 703 ◽  
Author(s):  
Andrea Barone ◽  
Maurizio Fedi ◽  
Pietro Tizzani ◽  
Raffaele Castaldo
Keyword(s):  
Multiscale Analysis ◽  
Cross Correlation ◽  
Ground Deformation ◽  
Vertical Component ◽  
Central Zone ◽  
Time Interval ◽  
Volcanic Complex ◽  
Magma Body ◽  
Deep Source ◽  
Good Agreement

Uturuncu volcano (southwestern Bolivia) is localized within one of the largest updoming volcanic zones, the Altiplano Puna Volcanic Complex (APVC). In several geodetic studies the observed uplift phenomenon is analyzed and modeled by considering a deep source, related to the Altiplano Puna Magma Body (APMB). In this framework, we perform a multiscale analysis on the 2003–2010 ENVISAT satellite data to investigate the existence of a multi-source scenario for this region. The proposed analysis is based on Cross-correlation and Multiridge method, pointing out the spatial and temporal multiscale properties of the deformation field. In particular, we analyze the vertical component of ground deformation during two time interval: within the 2005–2008 time interval an inflating source at 18.7 km depth beneath the central zone of the APVC is retrieved; this result is in good agreement with those proposed by several authors for the APMB. Between August 2006 and February 2007, we identify a further inflating source at 4.5 km depth, beneath Uturuncu volcano; the existence of this latter, located just below the 2009–2010 seismic swarm, is supported by petrological, geochemical, and geophysical evidence, indicating as a possible interpretative scenario the action of shallow, temporarily trapped fluids.

scholarly journals ISO-[CII]-Investigation of Cool HI Clouds in the Large Magellanic Cloud

1999 ◽  
Vol 190 ◽  
pp. 110-111
Author(s):  
M. Marx-Zimmer ◽  
F. Zimmer ◽  
U. Herbstmeier ◽  
J. M. Dickey
Keyword(s):  
Energy Balance ◽  
Radiation Field ◽  
Uv Radiation ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Heating And Cooling ◽  
First Results ◽  
Open Question

Despite a strong UV radiation field, the Large Magellanic Cloud (LMC) shows a relatively large abundance of cool HI gas. Neither CO- nor [CII]-lines have been detected in most of these regions in previous surveys. The energy balance of these cool clouds, of which some are located in warm surroundings, is still an open question. The improved resolution and sensitivity of the ISO telescope compared to previous measurements offers a unique opportunity to study the heating and cooling of these clouds in the LMC. Here we present first results of an investigation of the dominant cooling line, [CII] (158 μm), toward cool HI clouds.

scholarly journals Reproducibility of Preschool Personnel and Guardian Reports on Energy Balance-Related Behaviors and Their Correlates in Finnish Preschool Children

Children ◽  
2018 ◽  
Vol 5 (11) ◽  
pp. 144 ◽  
Author(s):  
Suvi Määttä ◽  
Henna Vepsäläinen ◽  
Reetta Lehto ◽  
Maijaliisa Erkkola ◽  
Eva Roos ◽  
...  
Keyword(s):  
Energy Balance ◽  
Screen Time ◽  
Time Interval ◽  
Good Reproducibility ◽  
Percentage Agreement ◽  
Food Frequency ◽  
Future Studies ◽  
Time Diary ◽  
Food Items ◽  
The Guardian

Valid and reliable non-objective assessments of guardian and preschool personnel reports are necessary when estimating young children’s health behaviors. This study examines the test-retest reproducibility of (a) guardian and preschool personnel questionnaires about correlates of preschool-aged children’s energy balance-related behaviors (EBRBs), (b) a screen time diary, and (c) a food frequency questionnaire (FFQ) reported by a guardian. A sample of guardians having preschool-aged children (N = 69) and preschool personnel (N = 61) completed questionnaires twice within a five-week time interval during April–May 2018 in Finland. Intra-class correlations (ICC), kappas, and percentage agreement were calculated to test the test-retest-reproducibility. The guardian questionnaire for correlates of the children’s EBRBs demonstrated mainly moderate to good reproducibility whereas the preschool personnel questionnaire of preschool correlates for children’s EBRBs was mostly good. The reproducibility of the screen time diary was good and FFQ food items showed mostly moderate reproducibility. The reproducibility of the FFQ foods items for vegetables, fruit, and berries was slightly better for the amount consumed than for the frequency of consumption. To conclude, all the instruments are acceptable for use in future studies.

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