The Experts below are selected from a list of 5508 Experts worldwide ranked by ideXlab platform
Qin Fang - One of the best experts on this subject based on the ideXlab platform.
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Low Temperature Collector for Yichang phosphate rock
Industrial Minerals and Processing, 2010Co-Authors: Qin FangAbstract:Soapstock of cottonseed oil was used as main Collector of phosphate rock with high grade in the tests.Screening tests of synergistic agents(anionic surfactant,cationic surfactant,non-ionic surfactant) of the Collector were conducted in the Hallimond bubble flotation tube.The results showed that yield of phosphate rock increased with increasing of dosage of anionic surfactants(SDS,sodium lauryl sulfonate,SDBS),so anionic surfactants had good synergistic action.The dosage of non-ionic surfactant(di(2-Ethylhexyl) ester phosphate,pyridine) needs to be controlled,if it is excessive,its synergistic action will reduce.A demonstration test was conducted also,the results showed that when pH = 8,flotation Temperature was 10～12 ℃,the dosage of SDS was 5% dosage of soapstock of cottonseed oil,the recovery of concentrate could increase 30.68%,and SDS could reduce sensitivity of soapstock of cottonseed oil to Temperature,it would lay a good foundation for further application of Low Temperature Collector of phosphate rock.
Ramon Pujol-nadal - One of the best experts on this subject based on the ideXlab platform.
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Optical losses due to tracking error estimation for a Low concentrating solar Collector
Energy Conversion and Management, 2015Co-Authors: Fabienne Sallaberry, Alberto García De Jalón, José-luis Torres, Ramon Pujol-nadalAbstract:Abstract The determination of the accuracy of a solar tracker used in domestic hot water solar Collectors is not yet standardized. However, while using optical concentration devices, it is important to use a solar tracker with adequate precision with regard to the specific optical concentration factor. Otherwise, the concentrator would sustain high optical losses due to the inadequate focusing of the solar radiation onto its receiver, despite having a good quality. This study is focused on the estimation of long-term optical losses due to the tracking error of a Low-Temperature Collector using Low-concentration optics. For this purpose, a testing procedure for the incidence angle modifier on the tracking plane is proposed to determinate the acceptance angle of its concentrator even with different longitudinal incidence angles along the focal line plane. Then, the impact of maximum tracking error angle upon the optical efficiency has been determined. Finally, the calculation of the long-term optical error due to the tracking errors, using the design angular tracking error declared by the manufacturer, is carried out. The maximum tracking error calculated for this Collector imply an optical loss of about 8.5%, which is high, but the average long-term optical loss calculated for one year was about 1%, which is reasonable for such Collectors used for domestic hot water.
Maximilian Möckl - One of the best experts on this subject based on the ideXlab platform.
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Real size experiments on reverse natural air convection between inclined parallel plates for new insulation methods in solar flat-plate Collectors
Journal of Solar Energy Engineering-transactions of The Asme, 2016Co-Authors: Thomas Beikircher, Vinicius Berger, Maximilian MöcklAbstract:Reverse natural air convection (hot plate top) was experimentally investigated between two inclined parallel aluminum plates (1 m × 2 m × 3 mm) with a separation distance of 20 mm to 100 mm. The inclination ϑ to the horizontal was varied from 0 deg to 90 deg. The mean Temperatures of the plates have been adjusted to 90 °C and 30 °C resulting in Rayleigh numbers Ra between 2.7 × 104 and 3.3 × 106. The experimental conditions correspond to the back side of an absorber in a typical solar flat-plate Collector, where the conventional insulation has been removed. The upper hot plate simulates the absorber and was electrically heated by an area heater, while the Temperature distribution over the plate was measured. The Lower cold plate was held isothermally by integrated water tubes and a thermostat. The side walls of the rectangular cavity were thermally connected to the colder plate and had a distance of 10 mm to the hot plate, comparable to a typical Collector casing. The experimentally obtained results for Nu (Ra,ϑ) were mathematically described and compared to rare reverse convection data of other authors, gained at smaller aspect ratios/fLow lengths and for adiabatic side walls: The formula of Elsherbiny approximately (within 10%) describes solar flat-plate Collectors between 0 deg and 60 deg inclination, while the relations of Arnold, Ozoe, and Inaba show large errors up to 50%. Additionally, we experimentally showed that pure air gap insulation (30–50 mm) has surprisingly acceptable loss coefficients between 1.3 and 2.5 W/m2K depending on Collector slope. It can be used as a cheap insulation method for Low Temperature Collector applications. Additionally, inserting an 25–50 μm thick aluminum film symmetrically between the plates, a new and efficient insulation method for the absorber of a solar flat-plate Collector was experimentally investigated: At plate distances of 30–50 mm, Temperatures beLow 100 °C and slopes beLow 45 deg, this compact and cheap film insulation was proven to be equivalent to dry mineral wool and avoids its disadvantage of worsening insulation properties due to humidity.
L.s. Vempati - One of the best experts on this subject based on the ideXlab platform.
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The effects of reverse-bias emitter-base stress on the cryogenic operation of advanced UHV/CVD Si- and SiGe-base bipolar transistors
Proceedings of International Reliability Physics Symposium RELPHY-96, 1996Co-Authors: J.a. Babcock, Alvin J. Joseph, John D. Cressler, L.s. VempatiAbstract:This paper demonstrates for the first time that hot carrier injection resulting from reverse-bias emitter-base (EB) stress at 300 K can result in significant shifts in the Low-Temperature electrical characteristics of epitaxially grown Si- and SiGe-base bipolar transistors. At Low injection, the observed Temperature dependence of the stress-induced base current leakage is attributed to a Poole-Frenkel field-enhanced tunneling mechanism. We have also observed for the first time a minor enhancement of the Low Temperature Collector current after EB stress at 300 K. This enhancement in the Collector current is attributed to a slight modification in the emitter-to-base space-charge-region via stress-induced trapped-charge located at or near the spacer oxide separating the emitter-base contact regions.
Fabienne Sallaberry - One of the best experts on this subject based on the ideXlab platform.
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Optical losses due to tracking error estimation for a Low concentrating solar Collector
Energy Conversion and Management, 2015Co-Authors: Fabienne Sallaberry, Alberto García De Jalón, José-luis Torres, Ramon Pujol-nadalAbstract:Abstract The determination of the accuracy of a solar tracker used in domestic hot water solar Collectors is not yet standardized. However, while using optical concentration devices, it is important to use a solar tracker with adequate precision with regard to the specific optical concentration factor. Otherwise, the concentrator would sustain high optical losses due to the inadequate focusing of the solar radiation onto its receiver, despite having a good quality. This study is focused on the estimation of long-term optical losses due to the tracking error of a Low-Temperature Collector using Low-concentration optics. For this purpose, a testing procedure for the incidence angle modifier on the tracking plane is proposed to determinate the acceptance angle of its concentrator even with different longitudinal incidence angles along the focal line plane. Then, the impact of maximum tracking error angle upon the optical efficiency has been determined. Finally, the calculation of the long-term optical error due to the tracking errors, using the design angular tracking error declared by the manufacturer, is carried out. The maximum tracking error calculated for this Collector imply an optical loss of about 8.5%, which is high, but the average long-term optical loss calculated for one year was about 1%, which is reasonable for such Collectors used for domestic hot water.
