Properties Of Collector Research Articles

Impact of voltage on the electric sliding tribological properties of current collectors against overhead lines

The impact of voltage on the electric sliding tribological properties of collectors gliding against overhead lines was experimentally investigated exploiting a block-on-disk test rig. The coefficient of friction, abrasion rate of collectors, temperature of the collectors and overhead lines, arc energy, and current-passing efficiency were collected or evaluated. The scar surfaces of current collectors were observed by SEM and analyzed by EDS. Results show that the voltage has a significant impact on the electric sliding tribological properties of collectors rubbing against overhead lines. The wear rate and temperature of collectors, and the arc energy all increase as the voltage increases. The influence mechanisms of voltage on the wear properties of collectors against overhead lines with current were also discussed.

Rolled electrodeposited copper foil with modified surface morphology as anode current collector for high performance lithium-ion batteries

Abstract A novel method that taking electrodeposited copper foil as a raw material undergoes asynchronous rolling and surface morphology modification at room temperature was proposed, and the rolled electrodeposited (RE) copper foil with excellent mechanical properties and modified surface morphology was obtained to be used as the anode current collector of high-performance lithium-ion batteries. The surface roughness of RE copper foil (Ra = 1.8 μm) is significantly higher than that of the traditional electrodeposited copper foil (Ra = 0.22 μm) when the thickness is 6 μm. The hilly surface morphology of RE copper foil helps to enhance the interfacial adhesion between current collector and active material, which contributes to the reduction of charge transfer resistance and improvement of specific capacity and rate performance. The mechanical properties of RE copper foil are significantly improved after asynchronous rolling. The excellent mechanical properties of RE copper foil current collector can maintain good electrical contact integrity of electrode active material during lithiation-de-lithiation and significantly improve the cycle life. The discharge capacity of RE electrode is maintained at 329.6 mAh g−1 and exhibits 91.1% capacity retention for 200 cycles at 500 mAg−1, which is much higher than the electrodes with electrodeposited and rolled copper foils as the current collector.

Collector for Copper-Arsenic Ore Flotation

Copper and scheelite concentrates are produced from scheelite-sulfide ores of the Vostok-2 deposit at the Primorsky processing plant. Chalcopyrite, gold, silver, and harmful impurities (arsenopyrite, pyrrhotite) are extracted into the copper concentrate. As a collector, dialkyldithiophosphate-type IMA-I413p reagent is used. Bulk sulfide concentrate is produced using activated carbon and trisodium phosphate; copper cleaner flotation is carried out in the medium of ferrous sulfate. The commercial copper concentrate contains 16 % copper, 33 g/t gold, and 280 g/t silver. The recovery of the metals is 67.6, 44.7, and 50.1 %, respectively. The weight fraction of arsenic in the ore fluctuates in the range of 0.04–0.25%, and that in the concentrate, 0.7–2.3 %. The enterprise looks for ways to increase recovery of the valuable metals and decrease content of arsenic in the copper concentrate to below 1% at the expense of increasing contrast in the separation of chalcopyrite from iron sulfides/arsenopyrite/pyrrhotite. For solving this problem, we performed a study of flotation properties of sulfide collectors based on dialkyldithiophosphates: BTF-15221, BTF -271, non-ionic collector Reaflot-277, and combinations of Reaflot-277 and IMA-I413p. Applying BTF-15221 collector allowed, as compared to the standard IMA-I413p reagent, to increase recovery of copper, gold, and silver and reduce arsenic content in the copper concentrate. The higher selectivity of BTF-15221 as compared to IMA-I413p was confirmed by the fact that the bulk of the increase in copper recovery and decrease in the weight fraction of arsenic in the copper concentrate was achieved in the selective cycle. Besides, during the study, surface activity and hydrophobizing ability of the water-soluble collectors were assessed. Using the example of BTF-15221, it was shown that improvement of the reagent collecting properties can be achieved not only due to increasing the surface activity of the reagent, but also at its decrease – in case of sufficient hydrophobizing ability of the reagent, close to that of the standard reagent. By adjusting these parameters through the use of low-molecular weight homologues of the main components, it is feasible to increase or decrease the selectivity and collecting ability of the reagent. Collector BTF-15221 is of practical interest for further testing in flotation of copper-arsenic and other ore types.

On the Correlation between the Geometrical Features and Thermal Efficiency of Flat-Plate Solar Collectors

This article presents the results of numerical and experimental studies on the impacts of the selected geometrical features of liquid solar collectors on their thermal efficiency. The experiments were carried out while meeting the requirements of the ISO 9806:2017 standard. Selected changes in the geometrical features were analysed by using fully functional prototypes of modified solar collectors. The correlations between the design and performance properties of the solar collectors were determined in accordance with the changes in the shape of the thermal efficiency η(T*m) curve.

Study on some aspects of solar photo voltaic thermal storage: A review

In the recent times energy crises is increasing specially in the developing nations where dependency on fossil fuels as their prime source which mainly includes oil, coal & gas energy emissions which are exhaustible in nature which leads to increase in greenhouse gases.As solar energy varies in nature with time of day and day of the year, direct solar radiations can now be stored using PV modules in many parts of the world. As a result, solar energy storage has been brought into solar power to eliminate these types of impediments. Review study mainly focuses on thermal properties of various Phase Change materials, air and water collector and its combination. PV module are often further utilized in several ways to achieve better efficiency. Furthermore, the utilization of the newest technologies like Nano fluids as well as phase change materials performance of the system is enhanced.Here our main focus is on solar energy storage because sun is an unlimited source of energy and maximum utilization can be done that’s why it is widely growing so in coming years it will acquire energy sector so installation costs can be recovered.Conclusion of the review study deals that with a concentration of 0.3 vol% of Nano fluid, thermal efficiency of hybrid PV/T, flat plate, and evacuated-tube solar collectors has increased by up to 96.3%, 95.13%, and 93.42%, respectively which depends on mass flow rate and temperature variation. Practically we can attain thermal efficiency (ηth) = 56.19% and electrical efficiency (ηele) = 13.75% after hybridization.

Influence of ion induced secondary electron emission on the stability of ionisation vacuum gauges

Surface modification of different materials exposed to an environment typical for hot cathode ionisation vacuum gauges was investigated. Such environment has been generated in a specially designed setup which simulates conditions in a Bayard-Alpert ionisation vacuum gauge. Characterisations by means of X-ray photoelectron spectroscopy and work function study have been performed before and after the sample exposure to Ar and H2 gas discharges. The majority of studied materials, such as molybdenum, gold or stainless steel, are considered to be of interest as ion collectors. In addition, experiments with copper and graphite revealed the major processes that are taking place during the exposure to an ionisation vacuum gauge environment. Since the stability of ionisation vacuum gauges can be affected by the change of secondary electron emission properties of ion collectors during the operation, the corresponding electron yield induced by bombardment of low energy Ar+ ions was measured. Results show that exposure to ionisation vacuum gauge environment contributes to development of hydrocarbon layers, independently from the collector material or the dominant species in the gas discharge. Therefore, ion induced secondary electron yield of clean materials will be changing during the gauge operation and eventually reach saturation regardless of the collector material. The results also show that the hydrocarbon layer cannot be desorbed by standard vacuum baking procedures, whilst ion bombardment will even increase the rate of the hydrocarbon layer formation.

Comparison of Solar Collector Testing Methods—Theory and Practice

One of the most important problems of operating solar heating systems involves variable efficiency depending on operating conditions. This problem is more pronounced in hybrid energy systems, where a solar installation cooperates with other segments based on conventional carriers of energy or renewable sources of energy. The operating cost of each segment of a hybrid system depends mainly on the resulting efficiency of solar installation. For over 40 years, the procedures of testing solar collectors have been undergoing development, testing, comparison and verification in order to create a procedure that would allow determining the thermal behavior of a solar collector without performing expensive and complicated experimental tests, usually based on the steady state condition. The proper determination of the static and dynamic properties of a solar collector is of key significance, as they constitute a basis for the design of a solar heating installation, as well as a control system. It is therefore important to conduct simulating and operating tests enabling the performance of a comparative analysis intended to indicate the degree to which the static and dynamic properties of a solar collector depend on the method used for their determination. The paper compares the static and dynamic properties of a flat solar collector determined by means of various methods. Based on the produced results, it has been concluded that the static and dynamic properties of a collector determined using various methods may differ from each other even by 50%. This means that it is possible to increase the efficiency of a solar heating installation via the use of an adaptive control algorithm, enabling real-time calculation of the values of characteristic parameters of solar installation, e.g., the time constant under operating conditions.

The Study of Thermal and Convective Heat Transfer in Flat Solar Collectors

The paper herein considers the study of convective heat transfer in flat plate solar collectors, as it is seen from the analysis on research of the heat transfer by a circular and flat tubes upon conforming the forced and free convections, placed vertically or horizontally with various liquid flow directions. There have been obtained Nusselt criterion dependencies in circular and flat pipes, which shows that corresponding equations allow defining the heat transfer intensity for all fluids with appropriate accuracy. As well there has been studied Prandtl criterion for fluids, which plays an important role in points spacing as regard to the curve. In each case the lines are with a tip 1/3, as in the research herein only the laminar conditions have been considered. The article herein considers the pilot tests based on tubular solar collectors with an absorbing shield. The aim of the experiment thereof is the research of thermal properties of tubular solar collector for producing hot water.

A super-lithiophilic nanocrystallization strategy for stable lithium metal anodes

Abstract Regulating the surface morphology or physical properties of current collectors, and thus tuning the wettability of liquefied Li toward substrates, is of tremendous interest for stabilizing Li metal anodes. Here we show the wettability of molten Li toward substrates can be tuned by nonreactive surface nanocrystallization strategy. The nanocrystallization structural features result in a surface energy reduction and generation of Laplace pressure, with both factors acting together to achieve a rapid adsorption of Li. The as-obtained Li composite anode exhibits a stable and low voltage hysteresis of less than 20 mV for over 2000 h at 0.5 mA cm−2 in a symmetrical cell owing to metal nanoseeds in the 3D scaffold. Equipped with the fabricated Li metal anode, a rechargeable Li metal battery with LiFePO4 cathode that features a high areal capacity of over 3 mA h cm−2 and long cycling stability is achieved. This finding provides a facile and cost-effective strategy for stabilizing Li metal for high-energy batteries.

Quantitative Analyses of the Interfacial Properties of Current Collectors at the Mesoscopic Level in Lithium Ion Batteries by Using Hierarchical Graphene.

At the mesoscopic level of commercial lithium ion battery (LIB), it is widely believed that the poor contacts between current collector (CC) and electrode materials (EM) lead to weak adhesions and large interfacial electric resistances. However, systematic quantitative analyses of the influence of the interfacial properties of CC are still scarce. Here, we built a model interface between CC and electrode materials by directly growing hierarchical graphene films on commercial Al foil CC, and we performed systematic quantitative studies of the interfacial properties therein. Our results show that the interfacial electric resistance dominates, i.e. ∼2 orders of magnitude higher than that of electrode materials. The interfacial resistance could be eliminated by hierarchical graphene interlayer. Cathode on CC with eliminated interfacial resistance could deliver much improved power density outputs. Our work quantifies the mesoscopic factors influencing the battery performance and offers practical guidelines of boosting the performance of LIBs and beyond.

Анализ изменения свойств коллекторов нефти и газа на различных этапах разработки нефтяных месторождений

Анализ изменения свойств коллекторов нефти и газа на различных этапах разработки нефтяных месторождений

Improving the flotation performance of an oxidized bituminous coal source

Numerous studies have been conducted describing the challenges with oxidized coal flotation. Common industrial collectors such as fuel oil are typically ineffective under natural conditions for the flotation of oxidized coal sources such as the Coalburg seam from the Central Appalachia coalfields of the U.S. Low plant flotation recovery values of less than 30% were realized in part due to the weak surface hydrophobicity and the clay coating that results from a reduced isoelectric point of the coal and low slurry pH values. Elevated pH values and the use of a model collector containing carboxylic groups improved flotation recovery values by nearly 45 absolute percentage points. Operating at pH values around 7.5 to disperse the clay slimes and provide more surface active dimer complexes produced from a carboxyl collector resulted in excellent flotation recovery values for a hard-to-float coal. Due to the frothing properties of the carboxyl collector, column flotation with froth washing was needed to provide product ash values as low as 7.5%.

Effect of conical strip inserts in a parabolic trough solar collector under turbulent flow

ABSTRACT This research focuses on the evaluation of the potential of conical strip inserts in absorber tube. Results of these experiment help in enhancing the heat transfer, friction, and thermal properties of parabolic trough collector. The novel design of conical strip insert produces swirl flows that boost the thermal properties of the parabolic trough collector. The heat transfer effect was found to be twist ratio dependent. Minimum enhancement in pressure drop due to the inclusion of inserts is observed.

Gutter oil, an alternative collector to traditional diesel collector for cleaner flotation of fine coal

ABSTRACT In order to realize cleaner production of coal flotation and reduce the dependence of traditional nonrenewable diesel collector, renewable collector was prepared from gutter oil and used for the flotation process. For contrast, flotation performance of gutter oil and traditional diesel collector was analyzed. The functional group composition of the two collectors was compared by infrared spectrum analysis (FTIR). In addition, the adsorption properties of collectors on the particle surface were analyzed by X-ray photoelectron spectroscopy (XPS). Then, flotation experiments were conducted to verify the applicability of renewable collector. FTIR results show that the main functional groups of diesel oil are C-C and C-H, while the gutter oil contains C = O and C-O besides hydrophobic groups, which results in higher ash content of clean coal. XPS results show that the hydrophobicity group content of coal increased significantly after the adsorption of collector. The flotation result show that the ash content of clean coal can be reduced to less than 10% and accompanied by more than 80% combustible matter recovery for both the gutter oil and diesel oil. This study demonstrates that the coal flotation process can become cleaner by using gutter oil as green collector.

Effects of cycle times and C-rate on mechanical properties of copper foil and adhesive strength of electrodes in commercial LiCoO2 LIBs

It is important to appraise the evolution of mechanical properties of current collectors and the adhesive strength of electrodes to reveal the chemical-mechanical coupling failure mechanism of lithium-ion batteries (LIBs), and to improve their cycling performance and cycling life. In this work, the mechanical properties of copper foil, anode, and cathode of commercial LIBs were studied under different cycling conditions by means of tensions with the aid of non-contact digital image correlation technique. It is found that different electrochemical cycle times and C-rates have great influence on the degradation of the mechanical properties of copper foil and the interfaces of graphite/copper foil and LiCoO2/alumina foil. The changes in elastic modulus, fracture strength and elongation of the copper foil were analyzed at 0.5C, 0.8C and 1.0C within 200 cycles, respectively. The adhesive strength of graphite/copper foil changes from its initial value 285.6 kPa to 55.5 kPa after 200 cycles at 1.0C, and the adhesive strength of LiCoO2/alumina foil decreases from its initial value 841.2 kPa to 132.8 kPa after 200 cycles at 1.0C.

Testing and modelling an unglazed photovoltaic thermal collector for application in Sichuan Basin

This paper mainly investigated the performance of a low-cost roll-bond water-type photovoltaic thermal (PVT) collector from both experimental and modelling approaches under the climatic conditions of Sichuan Basin of China. The design and manufacturing process of the PVT prototype adopted the available commercial PV panels for convenience and for reducing the manufacturing cost. The experiment measured all the main properties of the developed PVT module. The excellent heat transfer performance of its roll-bond absorber plate was also validated by outdoor steady-state tests. Then, the steady-state numerical models were used to simulate the performance of the PVT prototype in TRNSYS. By comparing the simulation and experimental results, two robust models were selected which have their own advantages in charactering the thermal and electrical properties of the PVT collector. Through validating the numerical models with experimental data, the deviation between the simulated and the measured values was further reduced. In addition, a complete photovoltaic thermal–domestic hot water (PVT-DHW) system with such PVT collectors was developed in TRNSYS, by which the annual system output and efficiency were predicted and analysed.

Performance Study on an Unglazed Photovoltaic Thermal Collector Running in Sichuan Basin

A performance study with experiments and TRNSYS simulations was conducted for a roll-bond water-type photovoltaic thermal (PVT) collector installed in Chengdu, Sichuan Basin. The measured ambient data and operation data were input to two TRNSYS models and their results were compared. The two numerical models have their own advantages in the simulation of thermal and electrical properties of the PVT collector. By calibrating the models with experimental data, the deviation between the simulated and the measured values was further reduced. In addition, the excellent performance of the roll-bond PVT absorber was also validated by the steady-state test results. However, the long-term system performance is subject to further investigations.

Contributions to System Integration of PV and PVT Collectors with Heat Pumps in Buildings

A common approach to improve self-consumption of photovoltaic (PV) generation in buildings with heat pumps (HP) is to overload the thermal storage capacities during times with surplus PV generation (hereinafter referred to as thermal overloading). The impact of battery capacity and domestic hot water (DHW) consumption on the effectiveness of this method in a single-family home (SFH) is evaluated through numerical simulations. Increased battery capacity is shown to decrease the effectiveness of thermal overloading. Regarding DHW consumption, temporal concentration is shown to have a stronger influence on the effectiveness of thermal overloading than total energy. Furthermore, the potential of photovoltaic-thermal collectors (PVT) as heat exchangers for air/brine/water heat pumps (ABWHP) is estimated. The results show that the properties of PVT collectors with high thermal conductivity are in the feasible range for application in a well-insulated SFH in Central European climate.

An appraisal of the geometry and energy efficiency of parabolic trough collectors with laser scanners and image processing

This paper presents an original method for the analysis of the geometric and optical properties of parabolic solar trough collectors using laser scanners and image processing techniques. The aim of the paper is to propose a methodology with which to automatically analyse geometric errors in the mirror and receiver, in addition to presenting an empirical assessment of one of the most important factors that determines the entire energy efficiency of solar plants, which is optical efficiency.The definition of canonical images has allowed us to characterise a set of parameters that evaluates errors on both the surface of the parabolic reflector and regarding the orientation of the receiver. In this framework, energy efficiency is established in terms of two parameters, denominated as the interception index and the concentration index.The proposed method has been tested on-site on real surfaces of parabolic solar trough collectors in an operating solar thermal plant. The results obtained are sufficiently accurate and reliable to be able to recommend that researchers and plants reproduce this method in this kind of installations.

Thermal Properties of Solar Collector Comprising Oscillating Heat Pipe in a Flat-Plate Structure and Water Heating System in Low-Temperature Conditions

Solar collectors are very important to the photothermal utilization of solar energy in low-temperature conditions. In this paper, a solar collector comprising an oscillating heat pipe in a flat-plate structure is designed and studied experimentally. The thermal properties are studied in detail, and we finally obtain the startup temperature and the expression of the instantaneous efficiency with a relative error of 5%. The results show that the impact of inclination angles on the startup properties of the solar collector is significant to the thermal properties. The comparisons of the efficiency of the present design and similar products are also displayed and discussed, showing that an oscillating heat pipe collector in a flat-plate structure overcomes the low efficiency, high startup temperature and bad pressure resistance of conventional solar collectors. In addition, the thermal properties of the water heating system based on the novel collector were also tested, illustrating the differences between the solar irradiance and the water heating system. Some improvements (e.g., shell material and assembly method) were made in this system design process to increase the heat transfer efficiency and solve the corrosion and pressure resistance problems.