Detonation of a thin explosive layer in evacuated tubes

1998 ◽  
Vol 34 (6) ◽  
pp. 651-661
Author(s):  
V. V. Mitrofanov ◽  
V. A. Subbotin
Keyword(s):  
Evacuated Tubes ◽  
Explosive Layer

scholarly journals MEASUREMENT OF THE EFFICIENCY OF EVACUATED TUBE SOLAR COLLECTORS UNDER VARIOUS OPERATING CONDITIONS

2012 ◽  
Vol 7 (3) ◽  
pp. 114-130 ◽  
Author(s):  
S. E. Zubriski ◽  
K. J. Dick
Keyword(s):  
Environmental Conditions ◽  
Operating Conditions ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Operating Efficiency ◽  
Space Heating ◽  
Solar Collectors ◽  
Auxiliary Equipment ◽  
Evacuated Tubes ◽  
Evacuated Tube

The operating efficiency of evacuated tubes themselves under varying environmental conditions and installation scenarios, independent of water and space heating auxiliary equipment, are not readily available values. Further, Manitoba specific data has not been established. The purpose of this research program was to measure the efficiency of evacuated tube solar collectors under various operating conditions including: the angle of inclination towards the incident solar radiation, heat transfer fluid flow rate, glazing installation, and number of evacuated tubes. The operating conditions and configurations were chosen to represent realistic or probable installation scenarios and environmental conditions. Furthermore, the research aimed to identify the suitability of evacuated tube solar collectors to each of the scenarios. These design values are of use for appropriate sizing of water or space heating systems, system configuration and optimization, and calculation of return on investment. The scope of the research project was limited to the efficiency of various configurations of a 32-tube panel, not the entire solar domestic hot water or space heating system. Thus, factors such as heat loss in the tubing, solar storage tank, and heat exchanger efficiency were not investigated. The findings indicated that efficiency varied by approximately 5% between the different collector configurations, as observed from the overlay graph of results. When the efficiency of a collector is considered within a system it is proposed that effectiveness may be a better measure of overall performance.

Numerical Investigation of Thermal Separators Within the Evacuated Tubes of a Water-in-Glass Solar Water Heater

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Asif Soopee ◽  
Abdel Anwar Hossen Khoodaruth ◽  
Anshu Prakash Murdan ◽  
Vishwamitra Oree
Keyword(s):  
Tilt Angle ◽  
Thermal Efficiency ◽  
Thermal Stratification ◽  
Maximum Deviation ◽  
Water Tank ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Thermal Distribution ◽  
Evacuated Tubes

The effects of thermal separators within the evacuated tubes of a water-in-glass solar water heater (SWH) were numerically investigated using the commercial computational fluid dynamics (CFD) software ANSYS fluent. To validate the three-dimensional (3D) model, an experiment was performed for the passive operation of the SWH for a fortnight period, of which 3 h of recorded data was selected. The Boussinesq's approximation was employed, and the respective solar irradiance and ambient temperature profiles were incorporated. A maximum deviation of only 2.06% was observed between the experimental and numerical results. The model was then adapted for the case where thermal separators are inserted within the evacuated tubes of the SWH and both cases were run for two tilt angles, 10 deg and 40 deg. The temperature and velocity profiles within the evacuated tubes were analyzed alongside the temperature contours, thermal stratification, and overall thermal efficiency of the SWH. At a 40 deg tilt, without thermal separators, the flow streams within the evacuated tubes are restrained, and a chaotic thermal behavior was observed, thereby restricting thermal distribution to the water stored in the SWH tank. A lower tilt angle (10 deg) provided a more desirable thermal distribution. With thermal separators, however, the tilt angle preference was reversed. A faster and more uniform thermal distribution was achieved within the water tank, with a sizeable reduction in the thermal stratification at a 40 deg tilt. The overall thermal efficiency of the SWH was improved by 4.11% and 4.14% for tilt angles of 10 deg and 40 deg, respectively.

scholarly journals Experimental Analysis of a Solar Still Coupled with Heat Pipe, Evacuated Tubes and Compound Parabolic Concentrators

2019 ◽  
Vol 577 ◽  
pp. 012179
Author(s):  
G Vivek ◽  
R Ratheesh ◽  
R Mukesh ◽  
G Sajan ◽  
R Haritha ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Experimental Analysis ◽  
Solar Still ◽  
Evacuated Tubes

Review of Materials and Environment Management for Solar Thermal Collectors

2014 ◽  
Vol 521 ◽  
pp. 539-542
Author(s):  
Da Yu Zheng ◽  
Juan Zheng ◽  
Xiang Yi Guan ◽  
Jia Zheng ◽  
Yi Ming Zhang
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pipe ◽  
Research Work ◽  
Solar Thermal ◽  
Senior Managers ◽  
Solar Thermal Collectors ◽  
Evacuated Tubes ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

To cover the main contributions and developments in solar thermal collectors through focusing on materials, heat transfer characteristics and manufacturing challenges. A range of published papers and internet research including research work on various solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube) were used. Evaluation of solar collectors performance is critiqued to aid solar technologies make the transition into a specific dominant solar collector. The sources are sorted into sections: finding an academic job, general advice, teaching, research and publishing, tenure and organizations. Provides information about types of solar thermal collectors, indicating what can be added by using evacuated tube collectors instead of flat plate collectors and what can be added by using heat pipe collectors instead of evacuated tubes. Focusing only on three types of solar thermal collectors (flat plate, evacuated tubes, and heat pipe tube). Useful source of information for consultancy and impartial advice for graduate students planning to do research in solar thermal technologies. This paper fulfils identified information about materials and heat transfer properties of materials and manufacturing challenges of these three solar thermal collectors. Describes some changes made to improve the environment which have had unforeseen and adverse effects on safety and the reasons why we need more case histories. Also discusses the reasons why there are no permanent solutions to safety problems and the reasons why senior managers should become more involved in safety problems.

Theoretical modeling and experimental analysis of solar still integrated with evacuated tubes

2016 ◽  
Vol 53 (6) ◽  
pp. 1943-1955 ◽  
Author(s):  
Hitesh Panchal ◽  
Anuradha Awasthi
Keyword(s):  
Experimental Analysis ◽  
Theoretical Modeling ◽  
Solar Still ◽  
Evacuated Tubes

Experimental Investigation of a Membrane Distillation System Using Solar Evacuated Tubes

2019 ◽  
Author(s):  
Ahmad Bamasag ◽  
Talal Alqahtani ◽  
Shahnawaz Sinha ◽  
Patrick Phelan
Keyword(s):  
Solar Energy ◽  
Membrane Separation ◽  
Waste Heat ◽  
Membrane Distillation ◽  
Effect Of Temperature ◽  
Low Grade ◽  
Solar Thermal Energy ◽  
Technical Performance ◽  
Temperature Polarization ◽  
Evacuated Tubes

Abstract Membrane distillation (MD) has been studied as a promising solution in the desalination industry but it has not been widely accepted or commercialized due to energy and cost concerns. MD is considered as a hybrid method that involves phase-change thermal processes and the use of membrane separation. Unlike conventional pressure-driven membrane methods such as reverse osmosis (RO), MD does not require intensive pre-treatment and can operate at lower pressure with higher salinities; but more importantly, it can utilize low-grade heat sources such as solar energy or waste heat for its operation. In this paper, an innovative MD module to directly employ solar thermal energy to assist in desalination is studied. MD systems that use solar energy as an external heater is investigated experimentally and theoretically. The proposed system, however, integrates hollow-fiber distillation membranes inside evacuated tubes solar collectors. As a result, the temperature is more uniformly distributed, minimizing the effect of temperature polarization, one of the key challenges of MD operation, thus can enhance the MD performance. The technical performance of the system is measured experimentally. The results of the proposed system are compared with a conventional MD process to investigate improvements in water production.

scholarly journals HPLC Analysis of Reduced and Oxidized Coenzyme Q10 in Human Plasma

2001 ◽  
Vol 47 (2) ◽  
pp. 256-265 ◽  
Author(s):  
Peter H Tang ◽  
Michael V Miles ◽  
Antonius DeGrauw ◽  
Andrew Hershey ◽  
Amadeo Pesce
Keyword(s):  
Human Plasma ◽  
Coenzyme Q10 ◽  
Venous Blood ◽  
Clinical Importance ◽  
Healthy Individuals ◽  
Reduction Procedure ◽  
Coulometric Detection ◽  
Evacuated Tubes ◽  
Reliable Quantification ◽  
Apparently Healthy

Abstract Background: The percentage of reduced coenzyme Q10 (CoQ10H2) in total coenzyme Q10 (TQ10) is decreased in plasma of patients with prematurity, hyperlipidemia, and liver disease. CoQ10H2 is, however, easily oxidized and difficult to measure, and therefore reliable quantification of plasma CoQ10H2 is of clinical importance. Methods: Venous blood was collected into evacuated tubes containing heparin, which were immediately placed on ice and promptly centrifuged at 4 °C. The plasma was harvested and stored in screw-top polypropylene tubes at −80 °C until analysis. After extraction with 1-propanol and centrifugation, the supernatant was injected directly into an HPLC system with coulometric detection. Results: The in-line reduction procedure permitted transformation of CoQ10 into CoQ10H2 and avoided artifactual oxidation of CoQ10H2. The electrochemical reduction yielded 99% CoQ10H2. Only 100 μL of plasma was required to simultaneously measure CoQ10H2 and CoQ10 over an analytical range of 10 μg/L to 4 mg/L. Intra- and interassay CVs for CoQ10 in human plasma were 1.2–4.9% across this range. Analytical recoveries were 95.8–101.0%. The percentage of CoQ10H2 in TQ10 was ∼96% in apparently healthy individuals. The method allowed analysis of up to 40 samples within an 8-h period. Conclusions: This optimized method for CoQ10H2 analysis provides rapid and precise results with the potential for high throughput. This method is specific and sufficiently sensitive for use in both clinical and research laboratories.

Measurement of Serum Ionized Calcium with the Ion-Exchange Electrode

1972 ◽  
Vol 18 (12) ◽  
pp. 1459-1462 ◽  
Author(s):  
V L Subryan ◽  
M M Popovtzer ◽  
S D Parks ◽  
E B Reeve
Keyword(s):  
Ion Exchange ◽  
Reproducibility Of Results ◽  
Room Temperature ◽  
Calcium Concentration ◽  
Ionized Calcium ◽  
Control Solution ◽  
Electrode Response ◽  
Serum Ionized Calcium ◽  
Evacuated Tubes

Abstract We found no differences in pH or ionized calcium concentration of serum from blood either collected into evacuated tubes or collected with syringes and separated under oil. Sera can be stored frozen in 1-ml plastic insulin-type syringes for one to three days without significant changes in pH or ionized calcium concentration, whereas storage under oil with or without re-equilibration with CO2 is associated with significant changes in both. Standards prepared with trypsin and triethanolamine give faster electrode response, and their ionized calcium concentrations remain unchanged for 6 h at room temperature. We suggest a not entirely satisfactory control solution of buffered protein, for use in assessing reproducibility of results.

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