Initial Water Temperature Research Articles

Development of an appropriate simple suspension method for valganciclovir medication

BackgroundValganciclovir (VGC) is essential for preventing cytomegalovirus infections after transplants in adult and pediatric patients. In pediatric patients, VGC tablets have to be pulverized so that they can be delivered via nasogastric tubes. The “simple suspension method” is usually used to suspend tablets in hot water in Japan. However, the optimal suspension conditions and metering methods for preparing VGC suspensions using the simple suspension method are unclear. The purpose of this study was to clarify these issues.MethodsVGC tablets were suspended in water (initial water temperature: 25 °C or 55 °C) using the simple suspension method. The residual rate of VGC after it had been suspended in hot water was determined using HPLC. In addition, the suspended solution was passed through 6, 8, and 12 Fr. gavage tubes. The VGC concentrations of suspensions produced using different preparation methods were also determined using HPLC.ResultsCracking the surfaces of VGC tablets and suspending them in water at an initial temperature of 55 °C was effective at dissolving the tablets. The VGC concentration of the suspension remained stable for at least 80 min. Furthermore, the VGC concentration remained stable for 48 h during cold dark storage. Cracking the surfaces of VGC tablets could be a more effective metering method than preparing powder from VGC tablets. In addition, little VGC remained in 6, 8, or 12 Fr. gavage tubes after VGC solution was passed through them.ConclusionThe amount of VGC should be measured carefully when preparing VGC solutions using the simple suspension method.

A SIMULATED STUDY ON THE EFFECT OF WATER TEMPERATURE ON COOLING EFFICIENCY OF WATER MIST FIRE EXTINGUISHERS

In this paper, the effect of initial water temperature on the cooling performance of a water mist fire suppression system has been investigated. A zero-dimensional analytical model was first developed to study the thermal and dynamic behavior of a single water droplet. The developed model was validated against available experimental data in the literature. The developed model was further extended to simulate the transient heating, evaporation, break-up, and liquid penetration length of a hollow-cone water spray. Results indicated that increasing the initial temperature of the water spray before injection resulted in a decrease in the initial size distribution of the spray droplets. It was further found that the evaporation time of the injected droplets decreased by about 11% and the cooling power of the pre-heated water mist system enhanced by 12% in exchange for increasing the initial temperature of the water spray by 10˚C. It was concluded that pre-heating the sprayed water droplets would likely improve the cooling efficiency of the water mist system. It could be also inferred that at equal cooling power, less water was consumed by the pre-heated spray compared to conventional water mist systems.

Solar Air-Heated Humidifiation - Dehumidifiation Desalination Unit

A solar powered desalination unit which working on a humidifiation –dehumidifiation technique (HDH) is one of the most important techniques used in brackish and seawater desalination especially in remote and rural areas. In the present study, a test-rig was designed and constructed for conducting a set of experiments on a solar assisted desalination unit working on a HDH principle under the prevailing conditions of Tajoura-Libya. Experiments were carried out on specifid days in March, 2019 at the laboratories of Center for Solar Energy Research and Studies (CSERS) at Tajoura. Th effct of diffrent design parameters and operating conditions on the performance of the unit and its productivity is closely investigated and interpreted. Results show that the productivity of the HDH unit decreases by increasing the process air mass flw rate. A signifiant improvement in the productivity of the unit is noticed when the feed water mass flw rate to the humidifir is increased. Furthermore, initial water temperature inside the tank has a remarked effct on the productivity of the unit. In order to obtain a reasonable amount of fresh water, the temperature of the water inside the tank should be increased. Increasing the cooling water mass flw rate to the dehumidifir leads to a corresponding decrease in the surface temperature of the cooling coil and hence the productivity of the unit is improved. Th Productivity of the unit is varying from its lower value of (0.903 kg/m2.day) to a higher value of (6.47 kg/m2.day). Thse values are obtained for one meter square of solar air heater area. Gained Output Ratio (GOR) values range from a minimum of (0.082) to a maximum of (0.572). It is reasonable when compared to ones in literature for the water-heated HDH units.

Experimental Investigation of Water Droplet Phase Change in Humidi-fied Air Flow

An experimental research method and an analysis of the results of a water droplet phase change in the additionally humidified air flow are presented. The diagrams of variation of the equivalent diameter of convectively heated water droplets are presented and analysed. The influence of initial water temperature and additionally humidifying air flow on the phase change of a droplet in transient regime is experimentally substantiated.

Performance assessment of 2×90 tph (afbc) boiler and study of hp heater

TNPL (Tamilnadu Newsprint and papers limited) unit-2 has two boilers; each boiler is 90 Tons per hour capacity. These are single drum, natural circulation water tube, under bed and over bed firing, top supported pressure parts and bed plate design atmospheric fluidized bed combustion (AFBC) boiler. Imported coal is the fuel for these boilers, for better operation, a performance assessment study of these boilers has been made, also HP (high pressure) heater is a special type of heat exchanger designed for recovering of heat from extraction steam to preheat feed water. They provide efficiency gain by increasing the initial water temperature. A study has been made how the HP heater can increase the efficiency of boilers. For HP heater motive steam from turbine extraction is used after generation of power.

Hydrogen generation from splitting water with Al–Bi(OH)3 composite promoted by NaCl

In this paper, a novel Al–Bi(OH)3 system hydrogen-generating material is investigated. Hydrolysis experiments show that the hydrolysis properties of the Al–10 wt% Bi(OH)3 composite are significantly improved by doping with sodium chloride, and the Al–10 wt% Bi(OH)3–5 wt% NaCl composite has a low activation energy (10.4 kJ mol−1). With the further optimization of milling time, the hydrogen yield of Al–10 wt% Bi(OH)3–5 wt% NaCl composite reaches 1000 mL g−1 in 1 min. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy and thermogravimetric analysis are applied to characterize the composite and explore the hydrolysis mechanism. The characterization results show that the activation of aluminum mainly comes from three factors: (1) The formation of alumina during ball milling plays an important role in preventing the agglomeration between Al–Bi, Al–Al and Bi–Bi; (2) Bismuth generated during ball milling can form micro-galvanic cell with aluminum to promote the corrosion of aluminum; (3) Sodium chloride as a grinding aid contributes to crush aluminum powder, and chloride ions facilitate the corrosion of aluminum in the hydrolysis process. In addition, the drying method and initial water temperature have a great influence on by-products. The composite is expected to be used in mobile emergency fuel cell due to its rapid hydrogen production capacity.

Performance Analysis of Solar Desalination System for Improved Productivity by using Waste Heat of Household Chimney

This work deals with the analysis of the proposed innovative humidification-dehumidification (HD) desalination unit in which waste hot air of kitchen chimney has been used for heating brackish water. The proposed system is configured with solar air heater also, thus both heated air and heated water has been used to improve the water yield of desalination unit compared to conventional system. Mathematical modeling of propose unit based on energy balance of flat plate air heater, humidifier, dehumidifier and brackish water tank has been used to evaluate the effect of operating condition. Potable water yield found to increase (with highest productivity of 6.5 kg/day) when mass flow rate of process air increases from 0.6 kg/min to 3 kg/min. Strong dependency of water mass flow rate has also been found as productivity increases (with maximum value of 6.7 kg/day and 7.5 kg/day) by increasing the mass flow rate of brackish water in humidifier and cold water in dehumidifier respectively. The higher initial temperature of brackish water also found beneficial as it increases productivity. Finally, the thermal performance of desalination unit has been evaluated in terms of Gain in Output Ratio and comparison has been made with conventional system. The higher GOR of the proposed system ensures the better utilization of thermal energy in potable water production.

Hot Water Deicing Method for Insulators Part 2: Analysis of Ice Melting Process, Deicing Efficiency and Safety Distance

In this paper, the heat balance integral method was employed to solve the internal temperature of ice layer and the position of melting interface by stages, due to its main advantage of converting the governing partial differential equation to an ordinary differential one, which can effectively reduce numerical efforts. Then the deicing time of hot water for insulator was calculated and analyzed. Taking LXY-120 insulator as the verification object, after natural icing at Xuefeng mountain natural icing test base, the validation experiments of deicing time were carried out in the natural environment. The initial water temperature and outlet pressure were optimized for deicing efficiency. Finally, the leakage current of water jet was measured. The research results indicate that the deicing rate increases and the energy consumption gradually decreases as the initial temperature of hot water increases. As the outlet pressure increases, the deicing rate increases. For the deicing condition of 1.2 mm nozzle, ambient temperature of -1 °C, wind speed of 3 m/s, ice weight of 2 kg/piece and deicing distance of 2 m, when the initial temperature of hot water and outlet pressure are 85.21 °C and 3.35 MPa respectively, the comprehensive deicing efficiency is the highest. The leakage current through water jet decreases with the increasing distance. The leakage current increases with the increase of water conductivity and outlet pressure. Hot water deicing for insulator in 110 kV system can be carried out according to the safety distance of the existing regulation.

水电开发对鱼类种群分布及生态类型变化的影响——以溪洛渡至向家坝河段为例

PDF HTML阅读 XML下载 导出引用 引用提醒 水电开发对鱼类种群分布及生态类型变化的影响——以溪洛渡至向家坝河段为例 DOI: 10.5846/stxb201901030025 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划（2016YFC0502205）；国家自然科学基金项目（51809176）；江苏省博后基金（2018K098B）；湖北省重点实验室2015年度开放课题（SXSN/4009） Distribution characteristics and ecological types changes in fish communities under hydropower development from Xiluodu to Xiangjiaba reach Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:梯级水库修建后自然河流形成了河相段和湖相段，而河流生境的改变对鱼类种群空间分布和生态类型变化产生了重要影响。为探究金沙江梯级水电开发对鱼类资源的影响，结合2018年5月渔获物和文献记载水库修建前后的渔获物数据，分析了鱼类群落组成及变化，优势物种及群落多样性特点，以及鱼类在河相、湖相段生态类型的变化。结果表明，梯级水库建设后溪洛渡至向家坝鱼类的种类数减少，随着水库的运行该减少趋势放缓，而大型鱼的种类数占比呈增长趋势。受生境变化的影响，鱼类优势物种发生变化，水库河相段和湖相段生态类型差异较大。生态类型组成上以缓流型、生活于水流中下层、产卵初始水温高于18℃等生态类型占优。研究表明，高坝大库的运行会造成鱼类种群以生态需求为目标，形成明显的空间分布和群落结构特征，而梯级水库建设导致的水动力条件差异是鱼类群落生态类型差异的内在驱动力。 Abstract:Natural rivers are divided into the riverine and lacustrine zones owing to the construction of cascade reservoirs. However, changes in habitat conditions have significant effects on the spatial distribution of fish and changes in ecological types. Changes in fish species composition, dominant species, community diversity and variation in fish ecological types between riverine and lacustrine zones were used to evaluate the effects of fish habitat. Data were obtained from the fishery survey in May 2018 and previous literature. The results showed that the number of fish species decreased and the rate of decrease slowed, whereas the proportion of big fish species increased after the construction of cascade reservoirs. The dominant species were constantly changing under the influence of habitat changes, and the ecological types of fish in the riverine and lacustrine zones were different. The species that inhabit the slow-flow zone, the middle and lower layers of water flow, and require initial spawning water temperature higher than 18℃ were the dominant ecological types. Finally, the study showed that because of fish autecology, there were distinct patterns in fish spatial distribution and community structure characteristics affected by the operation of high dam reservoirs. The riverine and lacustrine zones caused by the hydrodynamic variation of cascade reservoir construction were the internal driving force for the changes in fish community ecological types. 参考文献 相似文献 引证文献

Infiltration and Soil Water Distribution in Irrigation Furrows Treated with Polyacrylamide

HighlightsControl furrows with 1× inflow rates were compared with 3× advance inflows treated with 10 mg L-1 polymer (WSPAM).WSPAM reduced sediment loads in furrow streams by 89%, despite its 3× greater advance inflows.WSPAM furrow advance times and infiltrated volumes were greater than predicted from increased inflows alone.WSPAM enabled reduced upper-section infiltration and increased lower-section infiltration relative to control furrows.Abstract. Few if any studies have measured the effects of water-soluble anionic polyacrylamide (WSPAM) on infiltration and soil water distribution in different segments of irrigation furrows. We conducted a four-year study on a silt loam soil with 1.5% slopes. Control furrows received no WSPAM and inflows were 15.1 L min-1, whereas WSPAM was applied using 10 mg L-1 a.i. to 45 L min-1 inflows during furrow advance. Despite its greater advance phase inflow rates, WSPAM application reduced sediment concentrations in furrow streams by an average of 89% relative to the control. A surface irrigation model, WinSRFR 5.1, was used to separate furrow inflow rate effects on infiltration from that of WSPAM. Relative to results predicted by simulation for the entire furrow, the polymer treatment: (1) increased advance time an average 1.4-fold, (2) increased advance-phase infiltrated volume 1.5-fold, and (3) increased infiltration volume at the common opportunity time 1.2-fold. Hence, these effects resulted from WSPAM and not from differences in treatment inflow rates. Treatment infiltration amounts varied markedly among irrigations and years, as did the intensity of WSPAM effects. These were attributed mainly to differences in infiltration opportunity time, but temporal differences in soil water content during furrow formation, irrigation water electrical conductivity, initial soil surface water content and water temperature, and the irrigation-long, furrow-stream mean sediment content also appear to have influenced infiltration rates. Although inconsistent, WSPAM increased net furrow infiltration in the lower section and reduced infiltration in the upper section relative to control furrows. This effect could not be explained by the greater inflow rate and shorter advance time of the WSPAM treatments and was attributed to spatially variable WSPAM effects on infiltration opportunity time and possibly irrigation water viscosity. The WSPAM management approach, while protecting against furrow erosion, may potentially provide a means of improving irrigation uniformity and reducing associated percolation water and nutrient losses. Keywords: Furrow advance, Irrigation, Irrigation uniformity, Polymers.

An experimental study on the simultaneous removal of NO and SO2 with a new wet recycling process based on the micro-nano bubble water system.

The micronano bubble water system (MNBW) generated by a micronano bubble generator (MNBG) has the superior oxidation properties and can improve gas solubility. In the study, a new wet recycling process based on MNBW is proposed to simultaneously remove nitric oxide (NO) and sulfur dioxide (SO2). The important experimental parameters such as initial water pH, initial water temperature, NO and SO2 concentrations, and the presence of oxygen (O2) were investigated to explore the feasibility of desulfurization and denitration with MNBW. The experimental results showed that decreasing initial water pH or increasing initial water temperature and NO and SO2 concentrations were not conducive to the removal of NO or SO2. O2 could promote the removal of NO, but it had no effect on SO2 removal. In addition, SO2 removal efficiency always remained high and did not change obviously during the experimental period. However, NO removal efficiency gradually decreased in the first 50min and then became stable.

Performance assessment of a trifunctional system integrating solar PV, solar thermal, and radiative sky cooling

Radiative cooling (RC) with the outer space as a natural heat sink has stimulated widespread attention in the research community and has achieved rapid developments in recent years. However, most available radiative coolers exhibit low power density and long payback periods. To overcome such shortcomings, a cost-effective solution that integrates RC into a solar photovoltaic/thermal (PV/T) collector as a secondary function was proposed. In this study, a trifunctional photovoltaic–photothermic–radiative cooling (PV-PT-RC) system was developed. The proposed system could convert solar energy into electricity and/or heat during daytime and offer cooling energy at night through RC. A mathematical model was built to assess the performance of the PV-PT-RC system quantitatively and investigate the key performance indicators of the system numerically. Moreover, a practical-scale PV-PT-RC testing system was built, and experiments were performed to verify the effectiveness of the numerical model. Results revealed that the mean relative errors are less than 5% for the electrical power, aluminum plate temperature, and water temperature in the tank and 6.83% for the cooling power, thereby proving that the mathematical model can accurately assess the performance of the hybrid system. On the basis of the verified model, the overall performance of the system was examined under different insulation thicknesses, initial water temperatures in the tank, packing factors, panel emissivity values, and tank volumes. Furthermore, the results of the annual performance analysis suggested that the annual electrical, heat and cooling gains of the system in Eastern China are 479.67, 2369.07, and 1432.49 MJ, respectively.

Influence of initial water temperature on the synthesis of gas hydrate by the method of explosive boiling liquefied hydrogen-forming gas freon 134a in the volume of water

The paper presents an experimental study of the influence of the initial temperature of water on the amount of gas transferred to gas hydrate. The studies were carried out at constant operating parameters, with varying water temperatures before decompression. This work is a continuation of the study of a method of synthesis of gas hydrates developed by the team of authors, based on the explosive boiling of liquefied hydrate-forming gas (Freon 134a) in a volume of water.

Effects of utilizing nanofluid as working fluid in a lab-scale designed FPSC to improve thermal absorption and efficiency

The significance of using renewable energy has led to huge amount of studies on increasing the efficiency of the systems using these energies. The flat plate solar collector (FPSC) is one of the most common types of these systems. In this experimental study, we have made a change within the structure of a lab-scale flat-plate solar collector, and have increased its efficiency for public use. To this aim, a nanofluid containing TiO2 particles was used as working fluid which does not circulate inside the FPSC. Purified water as the agent fluid was circulating inside the piping system and water storage tank As a direct result, this mechanism increases the FPSC lifetime and reduces the costs compared to that of old versions. Moreover, a layer of N-TiO2 particles was applied on the outer side of the FPSC collector glass surface. This technique improves the self-cleaning properties of the surface, and also enhances the collector thermal efficiency. Studied range for volume fraction of TiO2 particles was from 0.1 % to 5%. The optimum volume fractions of TiO2 particles were utilized to study the collector performance. The measured average diameter of the TiO2 particles was about 20 nm. The nanofluid was prepared using a two-step method and by adding a sodium dodecyl sulfate (SDS) as surfactant. Results indicated that, using the nanofluid as working fluid, the collector efficiency was increased by about 45% and 17% for the volume fractions of 5% and 2.5% of TiO2 nanoparticles, respectively. Besides, an increase in the TiO2 particles volume fraction led to increment in absorbed heat by FPSC. Additionally, effects of initial temperature of tank water i.e. 0 °C, 10 °C, 20 °C, and 30 °C on the thermal efficiency was studied. Increasing the initial temperature showed positive influence on the efficiency. Moreover, regardless of whether the thermal connection is disconnected or connected, the collector does not lose its efficiency.

Experimental and Theoretical Study of Evaporation of a Volatile Liquid Lens on an Immiscible Liquid Surface.

The evaporation of a hexane lens on a distilled water surface was experimentally and theoretically studied. The formation of the hexane lens was recorded by a high-speed camera from the side to observe the variations of the contact diameters and contact angles. The experimental results showed that the shape variation of the hexane lens experienced the spreading stage and the evaporation stage. The spreading stage lasted for about 6% of the lens lifetime. For most time of the evaporation stage, the square of the lens contact radius decreased linearly with time, while the contact angle remained almost unchanged. During the final rapid evaporation stage (about 2% of the lens lifetime), the shape of the hexane lens changed and the lens shrank rapidly until it disappeared. A theoretical model based on diffusion-controlled evaporation under the constant contact angle mode was developed to describe the evaporation of the hexane lens on the water surface. In terms of geometry, the model assumes that a lens is composed of upper and lower spherical caps, and the apparent contact angle is defined based on the intersection of the two caps. The results calculated using the model were found to be in good agreement with the experimental data. Finally, the effects of initial lens volume, water temperature, and water surface deformation on lens evaporation were discussed through calculations. The results showed that increase in the water temperature and deformation of the water surface accelerated the evaporation process.

Decolourization of dye solutions by electrocoagulation: an investigation of the effect of operational parameters

This study investigates the influence of the current density on both removal of reactive black 5 dye (RB5) from water and energy consumption using aluminium-based electrocoagulation (EC) reactor. The influence of the current density was investigated by electrolysing coloured water samples containing 25 mg/l of RB5 for 60 min at three different current densities (1, 2, and 3 mA/cm2). While the initial pH, distance between electrodes, flow rate, and initial temperature of water were kept constant at 5, 4 mm, 1 L/h, and 20 ± 10C, respectively. The obtained results showed that both the removal of RB5 dye and energy consumption increased with the increase of the applied current density. For example, it has been found that the removal RB5 and the power consumption increased from about 95% to 99.5%, and the power consumption increased from 4.3 to 10.4 kWh/m3 as the current density increased from 1 to 3 mA/cm2, respectively.

The water heat pump operation under frost conditions on the evaporator surface

The conditions and characteristics of ice formation on the pipe surface of a heat pump evaporator which depends on water ( at a temperature lower than 280 K) as a low-grade energy source are investigated experimentally. Under the operating conditions of this heat pump, the ice thicknesses and temperatures values at freon pipe wall and for water in the evaporator are registered. The results allowed us to make a conclusion of the possibility to use a water source heat pump in practical applications under the conditions of partial ice coverage for the evaporator surface to heat up water in a condenser to 313 K. It is established from experiments that with the decrease in water initial temperature in the evaporator by 6 degrees, the maximum value of formed ice thickness on the evaporator surface is increased by 30 %. The dependence of Nusselt number on the natural convection characteristics undergoing phase change is established.

Nanoparticle Enhanced Interfacial Solar Photothermal Water Disinfection Demonstrated in 3-D Printed Flow-Through Reactors

Heat treatment, i.e., boiling or pasteurization, is the most widely recognized and practiced form of household water treatment. Considering recent advances in the development of light harvesting nanoparticles for solar-to-heat conversion, we envision that a nanomaterial enhanced water heating treatment system could obviate the need to use fuels or electricity to heat water by replacing the energy source with sunlight. In this study, we demonstrate that functional disinfection temperatures can be easily achieved with unconcentrated sunlight using a single layer interfacial photothermal film in direct contact with a tortuous flowing water channel. Photothermal films were fabricated by dispersing high concentrations of light harvesting nanoparticles, carbon black and Au nanorods, into a highly transparent curable polymer. Bench-scale 3-D printed reactors were employed to determine the effect of different parameters on reactor performance, such as channel height, retention time, flow rate, initial water temperature, and light intensity. Simulations demonstrate the scalability of the treatment system, predicting that a reactor footprint of 45 × 45 cm would be required for a photothermal treatment system that could produce 8 L of water per day with 8 h of sunlight at 1 Sun intensity.

Hydrogen production from hydrolysis of Al–Ga–In–SnCl2 composites

Highly active Al–Ga–In–SnCl2 composites for hydrogen production were prepared by mechanical ball milling. X-ray diffraction, scanning electron microscopy, and x-ray photoelectron spectroscopy analyses were used to characterize the composition and morphology of the composites. Moreover, the hydrogen production performance of the composites was systematically investigated at room temperature. The experiment results indicated that the addition of SnCl2 significantly enhanced the hydrolysis properties of Al–Ga–In ternary alloys. The Al-3%Ga-3%In-5%SnCl2 composite exhibited the optimal hydrogen production performance with a maximum hydrogen production of 1190 ml g−1 and a maximum generation rate of 1110 ml · min−1 · g−1 at 25 °C. Furthermore, we studied the effect of milling time, initial water temperature, and water quality on the final hydrogen production performance.

Enhancement Study of Ice Storage Performance in Circular Tank with Finned Tube

Combined experimental and numerical studies are conducted to study ice storage performance of an ice storage tank with finned tube. Axially arranged fins on the refrigerant tube are applied to enhance the solidification. The evolution of the solid–liquid interface and the variation of temperature of the typical position is examined. The effect of natural convection is discussed in detail. In addition, the effects of refrigerant temperature and initial water temperature on the ice storage performance are analyzed. The results indicate that the ice storage performance is enhanced by the metal fins remarkably. The defection of poor heat transfer after ice is formed can be solved by applying fins in ice storage devices. Natural convection leads to unnecessary mixing of water with different temperatures, lessening the cooling energy stored and acting as a disadvantage during solidification. Decreasing the refrigerant temperature and initial water temperature is beneficial for ice storage.