An Identification Size of The Interdigitated Flow Field on Pressure Loss Effects and Efficiencies in Vanadium Redox Flow Battery

In vanadium redox flow battery (VRFB), the active area for charge-discharge plays an important role on the optimization of the system. In this work, the optimum flow rate and current density of Nafion 117 membranes were examined and compared using 5cm2 and 25cm2 size of interdigitated flow field to operate VRFB at maximum efficiencies and discharge capacity. During discharge, flow field 25cm2 showed the highest discharge capacity of 367.5mAh at 10mAcm-2 as compared to 5cm2 flow filed which gave 221.9mAh. For battery efficiencies, three different parameters showed significant effects on different size of interdigitated flow field. 25 cm2 size of interdigitated flow field gave higher efficiencies than 5.0 cm2 up to 98%. This research offers fundamental understandings that bigger active area is needed to fully utilize the performance of VRFB.

WARM DEFORMATION BEHAVIOR OF A 65MN SPRING STEEL

The warm deformation behavior of 65Mn spring steel has been carried out by a thermomechanical simulator. The deformation temperatures are in the range of 550 ~ 700℃ and strain rates are in the range of 0.001 ~ 1 s-1. The deformation activation energy is calculated to be 486.829 KJ•mol-1. The strain compensated Arrhenius-type constitutive model was established. The relationship materials constants and strain were fitted with an 8th order polynomial. It was found that the strain has a significant influence on the instability map. At the strain is 0.3, the optimum flow zone may take place with the deformation temperatures higher than 626 ℃ and strain rate in the range of 0.001 ~ 1 s-1.

RESEARCH AND OPTIMISATION OF THE QUANTITATIVE AND QUALITATIVE CHARACTERISTICS OF GRAIN SHIPLOAD LOTS IN GRAIN TERMINALS

The structure of loading different crops onto vessels at the company Ukrelevatorprom’s grain terminal has been considered. The total grain shipped in 2012–2015 was comprised of 33.7–41.5% of maize, 19.7– 32.2% of wheat, 14.4–26.0% of rapeseed, 6.7–14.2% of barley, and 5.4– 11.0% of soya beans. When forming a 35,000-tonne grain shipload, grain lots stored in silos are sometimes of lower quality than contracts require: the protein and gluten contents can be inappropriate, or there can be smut grains or those damaged by sunn pests. The accepted technology of grain shipload formation does not guarantee that the grain quality will be uniform throughout the whole period of loading a vessel, especially in the beginning. In the first 1,000 tonnes of a grain shipload formed, the weight content of wet gluten was found to be 22.6% instead of 23%, the Falling Number was 145–180 s instead of 230s, and the content of smut grains was not the tolerable 5%, but 6.95–7.8%. The subsequent 2,000–3,000 tonnes of wheat, too, had the Falling Number lower than the contract prescribed (142–215 s), and only further on, its value achieved the required range 295–356 s. In the wheat sample formed from 5,000 tonnes, only the test values of the Falling Number (176s) and the content of smut grains (5.1%) were different from what the contract required. The calculated arithmetic means of the quality parameters of the 5,000-tonne wheat samples formed were practically the same as those determined experimentally, except for the values of the Falling Number and the smut grain content. The values of the coefficient of variation obtained showed that the grain lot was of non-uniform quality: it varied in such parameters as the foreign material (20.82–50.93%), sunn pest-damaged grains (7.41–25.76%), Falling Number (8.76–36.36%), and smut grain content (35.88–78.34%). Application of linear programming methods to optimise the shipload composition has allowed all the quality parameters to meet the contract requirements. Loading grain from all silos simultaneously, with the optimum flow ratio, will result in its even distribution in a shipload, and the grain lot will be of higher quality by all the parameters the contract specifies.

Karakteristik Hydrocyclone untuk Pemisahan Minyak dan Air

Eksplorasi minyak bumi dari sumur-sumur yang sudah tua menghasilkan minyak dengan kandungan air tinggi. Hydrocyclone suatu alat yang berfungsi untuk pemisahan cair-cair berdasarkan perbedaan berat jenis setiap komponen. Pemisahan ini terjadi dikarenanakan adanya gaya sentrifugal dan gaya gravitasi yang dihasilkan dari bentuk hydrocyclone yang seperti kerucut. Perancangan dan pembuatan hydrocyclone menghasilkan alat dengan spesifikasi sebagai berikut : diameter pipa masukan : 25,4 mm, diameter cylindrical section : 120 mm, tinggi cylindrical section : 120 mm, tinggi cone section : 600 mm, diameter pipa overflow : 25,4 mm, diameter pipa underflow : 25,4 mm. Laju alir optimum untuk pemisahan air-minyak tanah pada hydrocyclone adalah 91,8 liter/menit dengan kadar minyak tanah di overflow sebesar 11,4% dan kadar minyak tanah di underflow sebesar 3%.Petroleum exploration from old wells produces oil with a very high water content. Hydrocyclone is a device that functions for liquid-liquid separation based on differences in specific gravity of each component. This separation occurs due to the presence of centrifugal forces and gravitational forces resulting from cone-like forms of hydrocyclone. The design and manufacture of hydrocyclone produces tools with the following specifications: input pipe diameter: 25.4 mm, cylindrical section diameter: 120 mm, high cylindrical section: 120 mm, cone section height: 600 mm, overflow pipe diameter: 25.4 mm, underflow pipe diameter: 25.4 mm. The optimum flow rate for the separation of water-kerosene on hydrocyclone is 91.8 liters / minute with the level of kerosene in overflow of 11.4% and the level of kerosene in underflow of 3%.

Head lettuce production and nutrition in relation to nutrient solution flow

ABSTRACT The optimum flow rate of nutrient solution in hydroponic system can better nourish the crops, allowing healthy and faster growth of lettuce. However, flow also interferes with electric power consumption, so further researches are necessary, mainly on the effect of flow rate, nutrient accumulation and lettuce production. In this context, the aim of this study was to evaluate nutrition and production of head lettuce in relation to the nutrient solution flow in NFT hydroponic system. The treatments consisted of nutrient solution application at the flow rates 0.5; 1; 2, and 4 liters per minute in each cultivation channel. Five replicates per treatment consisted of 15 plants each. The flow in hydroponic systems to produce head lettuce alters the technical performance of the crop. Due to the greater nutrient accumulation in shoot and use efficiency of these elements, the highest production (g/plant) of head lettuce was obtained with a flow rate of 1 L/min of the nutrient solution.

Numerical Simulation of Flow Distribution in the Reactor Used for CFRPs Degradation under Supercritical Condition

Supercritical fluids with excellent decomposition and mass transfer capabilities can degrade the resin matrix of carbon fiber reinforced polymer (CFRPs) to recycle high-performance carbon fibers. The degradation rate of CFRPs was influenced by the velocity and temperature distributions of supercritical fluids in the reactor with mechanical stirring. The flow field model in the reactor was established during the degradation of CFRPs by supercritical ethanol. The velocity and temperature distributions in both the axial and radial directions were simulated when the stirrer was installed in the reactor at different heights. The simulation indicated that the flow distribution was uneven in the reactor and the position with optimum flow distribution for placing CFRPs was 45 %–70 % of the installation distance between underside of the impeller and the base of the reactor. The experiment shows mechanical stirring can significantly promote CFRPs degradation. When the installing height of the stirrer is 110 mm, the degradation rate of the epoxy resin is 10 % higher than that without stirring. The degradation rate of epoxy resin was also affected by the placement position of CFRPs in the reactor, and could be improved by approximately 14 % higher than that without mechanical stirring when the CFRPs were placed in the position with optimum flow distribution.