Initial Water Volume Research Articles

Development of compact electrolytic enrichment system for environmental tritium analysis.

The new electrolytic enrichment system with compact glass cell was designed. Three (Ni-Fe-Ni) electrodes are used, and electrolysis is carried out at a rate of 2.45g per h with constant current density of 120mA per cm2. This enrichment system allows the enrichment for small, limited sample volumes (e.g. Tritiated Water (HTO) recovered from air). With an initial water volume of 100ml, the tritium enrichment factor of 7 within 2days and a detection limit of 0.12Bq per L can be obtained by Liquid Scintillation Counter (LSC) measurement for 1000minutes, which is better than the direct measurement with 50ml sample water using large vial. It is also possible to perform the high enrichment process. The initial sample volume of 700ml enriched for 12days by manual refilling yields a tritium enrichment factor of around 43 and detection limit of 0.02Bq per L for 1000minutes of LSC measurement.

Design of Terrace-Based Hydroponic System using Hydraulic Ram Pump

The primary objective of the study is to design a terrace-based hydroponic system incorporating a hydraulic ram pump and to evaluate the effectiveness of the hydraulic ram pump in terms of drive head, flow rate, and delivery head, while also assessing its overall performance, particularly in terms of water loss percentage. The hydraulic ram pump can deliver a delivery head of 200 cm. To achieve this 200 cm delivery head, a drive head of 20 cm and a drive pipe length of 60 cm are necessary. The flow rate of the ram pump at the delivery pipe is 1.13 liters per minute. The water balance equation was employed to quantify water loss, considering parameters such as initial water volume in storage tanks, water collected in excess water collectors, and overall water losses during a system operation. The study's key findings reveal that during each 15-minute operational cycle, the terrace-based hydroponic system, incorporating a hydraulic ram pump, experienced an average water loss of 4.59 liters, equating to a 2.7% water loss percentage. This 2.7% loss could have a significant impact on sustainability if the system were to be upscaled.

Effect of Surfactants on the Synthesis and Dissociation of Gas Hydrates

The synthesis and dissociation of methane hydrate and carbon dioxide hydrate were studied. Nonflammable gas hydrates can be used to extinguish flames in confined spaces. To increase the extinguishing efficiency, it is necessary to increase the dissociation rate (gas release rate) by using surfactant. The work investigates gas hydrates synthesized using sodium dodecyl sulfate (SDS). Experimental studies were carried out in wide ranges of surfactant concentration, the number of the stirrer revolutions and the initial water volume. To achieve the maximum rate of synthesis and dissociation, optimization of the specified parameters was performed. The influence of the key parameters on the dissociation rate was investigated experimentally and theoretically. The novelty of the work lies in solving a complex of interrelated tasks on the synthesis and dissociation of gas hydrate. It is shown that in order to achieve the maximum dissociation rate of carbon dioxide hydrate, it is necessary to optimize the following parameters: the diameter of the particles and their porosity, the porosity of the layer and the external heat flux.

Case study of variable speed photovoltaic direct-driven ice-storage air conditioning system in Wuhu

In order to meet the contradiction between the growing demand for refrigeration and energy scarcity, this paper proposes a novel photovoltaic ice storage air conditioning system. The system is directly driven by a photovoltaic array. The performance of the system was studied through experiments, and a mathematical model was constructed for comparative verification. The experimental results show that the daytime cooling COP of the system is 1.18, the photovoltaic conversion efficiency is 6.29 %, and the nighttime cooling time is 9 h, which basically meets the cooling needs. Through simulation, the performance of the system was optimized, and the results showed that an increase in the initial water volume and temperature of the ice storage tank would increase the cooling COP; the spacing between evaporator pipes increased from 45 mm to 60 mm, resulting in a 7.11% increase in COP; the optimal spacing between evaporator fins is 9 mm, which improves performance by 9.11 %.

Performance prediction of a solar hot water system with change of circulating pump efficiency in solar collectors

In this study a mathematical model was developed to predict operating performance of the solar collector under specified weather conditions at Jeju Island, Korea. The optimum mass flow rate through collector based on the relationship between the useful heat gain of solar collector and the electricity consumption of solar pump is investigated. Besides, the effect of various parameters such as solar collector area, initial water temperature and volume of storage tank is analyzed. The results of the simulation show that the system performance increased about 1.33% at m = 0 . 442 kg/s with the new coefficient K c = 0 . 17 . Furthermore the system performance is affected strongly by the change of collector area, initial water temperature and volume of storage tank It should give concise information on the aims, the methods, the results and the conclusions of the paper. Its length should not exceed 200 words.

Demonstration of a partially automated assessment approach to create an individualised, open-ended modelling worksheet

Partially automated assessment is implemented via the ‘Printable worksheet’ mode in the Numbas e-assessment system to create a mathematical modelling worksheet which is individualised with random parameters but completed and marked as if it were a non-automated piece of coursework, preserving validity while reducing the risk of academic misconduct via copying and collusion. A simple modelling scenario is used for this demonstration. A cylindrical tank of water is draining through a small hole in its base, with the size of the tank, size of the hole and initial volume of water randomised so that the details are different for each student. Students are guided through deriving a model of the movement of water out of their version of the tank, asked to compute the expected time for it to empty and asked to discuss some aspects of the model and their findings in a discursive narrative report.

Vase Life Evaluation of Three Greek Tulip Species Compared with a Commercial Cultivar

Aiming at evaluating new candidate species for the cut flower market of Greece and beyond, in this study, the vase life of three Greek tulip plant species, Tulipa cretica ‘Hilde’ (CRH, local endemic of Crete, Greece), T. clusiana ‘Chrysantha’ (CLC, naturalized in Chios Island, Greece), and T. australis (AUS, native in the Mediterranean and Greece), was investigated in comparison to the commercial tulip hybrid Île-de-France (IDF). To this end, pre-cooled at 4 °C bulbs of the abovementioned Greek tulip plant species were bought from Dutch nurseries and grown in pots placed in unheated greenhouses located at two different climatic conditions in Northern Greece. The plants were uprooted when the flowers reached a slightly open stage. Half of the flowering stems were immediately placed into bottles with deionized water, while the rest were placed in a preservative solution containing citric acid 5% and sulfuric acid 1% and then remained under laboratory conditions until the entire tepal wilted (end of vase life). The measurements performed concerned: (a) flower stem length and flower maximum diameter, (b) fresh weight (FW) of initial stems, leaves, flowers, and bulbs and at the end of vase life, (c) flower color parameters (L, a, b, c, and H) in all treated flowers, (d) leaf chlorophyll content (SPAD values), and (e) initial and final water volume after removing the flowering stems. The aforementioned measurements showed that CRH cut flowers may exhibit consistent floral opening patterns and were associated with a long mean vase life of 5.7 days, which can be further prolonged to 6.5 days by carefully selecting a cultivation location with proper climatic conditions. The vase life of CLC cut flowers was significantly affected by the climatic parameters (temperature) of the area where the plants were cultivated. The immersion of cut flowering stems in a preservative solution with citric and sulfuric acids did not yield a notable increase in the longevity of cut flowers during the postharvest period. Moreover, this treatment did not have any significant impact on leaf chlorophyll content or flower color at the end of the flowers’ vase life. The data of this work show that cut flowers from the native species T. cretica and T. clusiana have satisfactory vase life, especially when plants were grown in favorable climate condition; the latter is an important criterion for their entry into the cut flower market.

A hyperspectral detection model for permeability coefficient of debris flow fine-grained sediments, Southwestern China

ABSTRACT Fine-grained sediments are Quaternary sediments with grain sizes of not more than 2 mm. They start first when meeting water, their stability is related to the initial water volume triggering debris flow, and thus plays an important role in debris flow hazards early warning. The permeability coefficient is the inter-controlled factor of fine-grained sediment stability. However, there is no hyperspectral model for detecting the fine-grained sediment permeability coefficient in large areas, which seriously affects the progress of debris flow hazards early warning. Therefore, it is of great significance to establish a hyperspectral detection model for the permeability coefficient of fine-grained sediments. Taking Beichuan County, Southwestern China as the case, a permeability coefficient hyperspectral detection model was established. The results show that eight bands are sensitive to the permeability coefficient with a correlation coefficient (R) of 0.6343. T-test on the model shows that P-values for sensitive bands are all less than 0.05, indicating the established model has a good prediction ability with a precision of 85.83%. These sensitive bands also indicate the spectral characteristics of the permeability coefficient. Therefore, it provides a scientific basis for fine-grained sediment stability detection in large areas and lays a theoretical foundation for debris flow hazards’ early warning.

A theoretical and experimental investigation of batch oil-water gravity separation

Gravity separation of oil-water emulsions is an industrially crucial process. Mechanistic models for a batch separation process can immensely be beneficial by linking emulsion experimental characterization to optimal industrial equipment design. For this reason, a mathematical model for this process was developed, which considers droplets settling/rising due to buoyancy force, binary and interfacial coalescence of the droplets using a film drainage model, and formation of a homophase. Various models for the droplet slip velocity were compared, which exhibit similar predictions using the Kumar and Hartland model and Behzadi et al. model while different from the Zaki and Richardson model. Another crucial part of the model is the proper mathematical description for forming the dense-packed layer (DPL). This study proposes a new approach to improve the prediction for the DPL formation by introducing diffusion in the model as an advection-diffusion equation. Accordingly, a suitable closure model for effective diffusion coefficient was selected, ensuring physical volume fraction range (0−1) in the system. Finally, the proposed closure model was tuned using experimental data for a stabilized water in model oil emulsion. Experiments were performed by the NMR technique for a wide range of initial water volume fractions (20–60%). The model prediction agrees well with the experiments. In particular, simultaneous agreement with all cases having various initial volume fractions and droplet size distributions suggests that this model can be generalized and applied to a wide range of oil and water emulsions. Additionally, the developed model shows promise as it can ensure physical values for volume fractions.

Rectal Temperature Cooling Using 2 Cold-Water Immersion Preparation Strategies.

Cold-water immersion (CWI) is essential to treat patients with exertional heatstroke (EHS). Experts recommend that patients with EHS be immersed in water between 1.7°C and 15°C within 30 minutes of collapse. Some clinicians fill cooling tubs several hours before exercise, keep the tub in hot conditions, and then add ice in the event of an EHS emergency. No data exist on whether adding ice to water at the time of treatment is as effective as keeping water in the recommended range. To (1) compare the cooling rates of individuals immersed in a water bath kept at 10°C (CON) or 17°C water with 75.7 L (20 gal) of ice added to it immediately upon immersion (ICE) and (2) examine perceptual responses before, during, and after cooling. Crossover study. Laboratory. Twelve individuals (7 men, 5 women; age = 22 ± 2 years, height = 176.0 ± 12.8 cm, mass = 74.5 ± 10.6 kg). Participants exercised in the heat until rectal temperature was 39.5°C. They then immersed themselves in CON (initial water volume = 681 ± 7.6 L, 10.0°C ± 0.03°C) or ICE (initial water volume = 605.7 ± 7.6 L water at 17.0°C ± 0.03°C with 75.7 L ice) until rectal temperature was 38°C. Thermal sensation and environmental symptoms questionnaire (ESQ) responses were recorded before, during, and after exercise and cooling. Rectal temperature cooling rates, thermal sensation, ESQ responses. Participants exercised for similar durations (CON = 39.6 ± 18.2 minutes, ICE = 38.8 ± 14.3 minutes, Z11 = 0.94, P = .38) and had similar thermal sensation and ESQ scores immediately postexercise each day (P values > .05). They cooled quickly and at similar rates in both conditions (CON = 0.20°C ± 0.06°C/min, ICE = 0.21°C ± 0.12°C/min, t12 = 0.72, P = .49). Perception data were similar between conditions during and after cooling (P < .05). Clinicians can cool patients with EHS quickly by adding ice to water that has warmed to above expert recommendations. Adding ice to a water bath at the time of EHS emergencies could save time, energy, and resources instead of always maintaining water bath temperatures within expert-recommended ranges.

Flushing Capacity of a Stored Volume of Water: An Experimental Study

This paper presents a systematic analysis of the hydraulic flushing capacity of a stored volume of water to remove sediments. This analysis is based on 90 laboratory experiments in which the volume of sediment evacuated was measured for varying initial volumes of water, three bed slopes, and three sediment sizes. The experiments consisted of the rapid emptying of a reservoir by means of suddenly opening a tilting gate downstream. This opening produced an accelerated flow which eroded the mobile bed of the reservoir. The efficacy of flushing, herein defined as the ratio of the volume of sediments evacuated to the volume of water released, increased with the initial slope, and decreased as the initial volume of water increased. In relation to the sediment size, while the results obtained for the coarse and medium sands were very similar to each other, the results obtained for the fine sand were affected by the existence of apparent cohesion in the mobile bed. In comparison to the results obtained for the medium and coarse sands, this apparent cohesion reduced the volume of sediment evacuated by a given volume of water and hence, the efficacy of flushing.

Displacing water from a low spot in a pipeline by a turbulent oil flow: Experiments and simulations

Water may accumulate at low sections of oil transportation pipelines. Continuous removal of the water by the oil is essential to avoid possible damages to the pipeline and ensure proper oil flow. Lab-scale experiments were performed to determine the critical oil velocity that enables the removal of accumulated water by turbulent oil flow and to measure the water propagation velocity at supercritical oil velocities. Effects of the riser inclination, initial water volume, and oil flow rate on the oil–water flow phenomena were documented. The data obtained were compared with results of 2D and 3D numerical simulations. The oil viscosity and pipe diameter effects were tested via numerical simulations. More viscous oils have been found to reduce the critical oil velocity and increase water propagation velocities, however with a rather weak effect. The critical oil velocity increases with the pipe diameter and the water propagation velocity is reduced.

Study on thrust performance of small water rocket launch

For water rocket test of low cost, quick assembly and simple, based on the single water rocket, using Bernoulli equation, the ideal gas adiabatic model and mass conservation theorem, this paper derived both the calculation method of thrust rocket the bottle under the different initial water volume ratio of water pressure, and the rule about how the water rocket thrust and pressure performance change. It is found that the pressure, the jet velocity of the water relative to the water rocket body and thrust of water rocket will decrease with the decrease of water amount under different initial charging pressure and different initial water amount. If the initial pressure is higher, the water rocket will gain more energy and launch faster; However, it doesn’t mean that the more initial water storage ratio is, the better. The maximum velocity obtained by water rocket under the same initial pressure increases first and then decreases with the initial water storage ratio and the optimal initial water storage ratio increases with the increase of initial pressure. According to data calculation, the numerical value increases with the increase of initial pressure. The optimal performance of water rocket can be obtained by taking the maximum pressure and the corresponding optimal initial injection water when the water rocket body is allowed.

Hydrogen production from low temperature supercritical water Co-Gasification of low rank lignites with biomass

Co–gasification of low rank lignite (Çan) with sorghum energy crop was investigated under low temperature conditions with supercritical water (773 K, 26.9 MPa). The effects of the water volume in the reactor, blending ratios of the coal/sorghum mixtures, the use of different catalysts, and the variation of feedstock concentrations on the gasification efficiency, product distribution, and hydrogen yields were evaluated. Synergistic effects were observed for both the gasification efficiency and the hydrogen yield with a coal content of 25 wt% in the coal/biomass mixture. Increasing the initial water volume, decreasing the feedstock concentration, and using the alkali metal catalysts Na2CO3 and K2CO3 significantly increased the gasification efficiency and the hydrogen yield. In experiments with CaO, almost all the carbon dioxide formed was isolated from the gas product during gasification, and the hydrogen yield was more than 70%. The liquid products were mainly composed of alkylphenols and their derivatives.

Experimental and numerical investigation on a novel photovoltaic direct-driven ice storage air-conditioning system

In this paper, a photovoltaic direct-driven ice storage air-conditioning (PDISAC) system is proposed and performance of the system is experimentally and theoretically investigated. The proposed system is a battery or inverter less photovoltaic direct-driven system where the DC compressor is directly connected to the PV array. Through the test, it has been found that the proposed system was able to lower the test room temperature below 298.15 K, while the reference room temperature was 306.15 K. Moreover, the experimental refrigeration efficiency and solar-energy utilization efficiency were reported 1.028 and 7.1% respectively. Then, a mathematical model for the progress of ice making and cold storage is presented and verified by the experimental results. Besides, the factors such as the ambient temperature, the initial water temperature and volume in the ice storage tank, and the thickness of the ice layer surrounding the coil have been studied. The simulation results indicate that the initial heat transfer rate at the condensation side drops by 10.8% and refrigeration efficiency drops by 32.7% with the ambient temperature increasing from 298.15 K to 308.15 K. The increment of initial water temperature and initial water volume will lead to an increase in refrigerating capacity and refrigeration efficiency.

Arsenic Removal from Highly Contaminated Groundwater by Iron Electrocoagulation—Investigation of Process Parameters and Iron Dosage Calculation

Electrocoagulation (EC) is gaining increased attention for water treatment as it efficiently removes various water contaminants. Therefore, EC was applied to remove arsenic from groundwater of a highly contaminated site in Hamburg, Germany. Groundwater containing 3250 and 14,600 µg/L arsenic, mainly as Arsenite (As(III)), was treated in three different EC batch reactors using a monopolar parallel electrode-configuration. This study focused on iron EC with constant current densities and variable voltage, to investigate the influence of current density, surface to volume ratio, initial arsenic concentration and water volume on the removal of arsenic and the influences on the groundwater composition. Arsenic removal &gt;99.9% was achieved for configurations with high iron dosage after four hours of EC treatment. German drinking water standard for arsenic (&lt;10 µg/L) was obtained after around two hours depending on the applied current densities. Arsenic removal efficiency shows independence from current density, surface to volume ratio, initial concentration and water volume, with respect to the calculated iron dosage. Consequently, the dimensioning and regime of efficient operation of the EC reactor for arsenic removal from groundwater can be calculated solely from the iron dosage determined by the applied current.

Child hand contamination is associated with subsequent pediatric diarrhea in rural Democratic Republic of the Congo (REDUCE Program).

The Reducing Enteropathy, Undernutrition, and Contamination in the Environment (REDUCE) program focuses on identifying exposure pathways to faecal pathogens for young children in the Democratic Republic of the Congo (DRC) and on developing scalable interventions to reduce faecal contamination from these pathways. A prospective cohort study of 690 participants was conducted to investigate the association between hand, food, and environmental faecal contamination and diarrhoeal disease prevalence among young children in Walungu Territory, South Kivu, DRC. A total of 1923 hand rinse, soil, food, object, surface, stored water and water source samples were collected during unannounced spot checks after baseline enrolment and analysed for Escherichia coli. Caregiver reports of diarrhoea were obtained from children<5years at a 6-month follow-up. E.coli was detected in 73% of child and caregiver hand-rinse samples, 69% of soil samples from child play spaces, 54% of child food samples, 38% of objects and surfaces children were observed putting in their mouths, 74% of stored water samples, and 40% of source water samples. Children<5years with E. coli on their hands had significantly higher odds of diarrhoea at the 6-month follow-up (odds ratio: 2.03 (95% confidence interval: 1.05, 3.92)). The cohort study findings from the REDUCE program have shown that child hand contamination is associated with diarrhoeal disease in rural DRC, and that there is high faecal contamination in child plays spaces and food. These findings provide evidence demonstrating the urgent need to provide clean play spaces for young children and interventions targeting hand hygiene to reduce paediatric exposure to faecal pathogens.

Amplification of flood discharge caused by the cascading failure of landslide dams

The cascading failure of multiple landslide dams can trigger a larger peak flood discharge than that caused by a single dam failure. Therefore, for an accurate numerical simulation, it is essential to elucidate the primary factors affecting the peak discharge of the flood caused by a cascading failure, which is the purpose of the current study. First, flume experiments were done on the cascading failure of two landslide dams under different upstream dam heights, downstream dam heights, and initial downstream reservoir water volumes. Then, the experimental results were reproduced using a numerical simulation model representing landslide dam erosion resulting from overtopping flow. Finally, the factors influencing the peak flood discharge caused by the cascading failure were analyzed using the numerical simulation model. Experimental results indicated that the inflow discharge into the downstream dam at the time when the downstream dam height began to rapidly erode was the main factor responsible for a cascading failure generating a larger peak flood discharge than that generated by a single dam failure. Furthermore, the results of a sensitivity analysis suggested that the upstream and downstream dam heights, initial water volume in the reservoir of the downstream dam, upstream and downstream dam crest lengths, and distance between two dams were among the most important factors in predicting the flood discharge caused by the cascading failure of multiple landslide dams.

The Tsunami Model of Mount Anak Krakatau Landslide in 2018 and Its Future Potential Hazard to the Coastal Infrastructures in Sunda Strait

This study is motivated by the tsunami event caused by Mount Anak Krakatau flank collapse on 22nd December 2018 which affected vital areas in Southern Sumatera and Western Java. A tsunami simulation will be carried out by using a 2D Non-Linear Shallow Water Equation Model to estimate the volume of the initial source as well as their tsunami mode at shores. Various scenarios of initial water volume replicating the tsunami source were applied, where the tsunami heights and their periods reach shores are validated with mareogram data at four Stations. The fact that the remaining materials of Mount Anak Krakatau after the 2018 event are still potential to generate a hazardous tsunami in the future and threaten the coastal infrastructures along the coastal Sunda Strait area. In this study, the validated parameters resulting from the 2018 event above are applied to model of the plausible worst scenario where the entire of the flank of Mount Anak Krakatau potentially collapses in the future. The study is important to estimate the tsunami hazard potential in the future that obviously influencing major activities and life’s in vital industrial-urban area in Southern Sumatera and Western Java.

CALCULATION OF THE MORPHOMETRIC CHARACTERISTICS OF THE CLOSURE CHANNEL AND THE EXTREME DISCHARGE DURING BREAKTHROUGHS OF GROUND DAMS

The work is devoted to the calculation of the size of the closure channel in the ground dams when water is poured from the water reservoir through peak and the extreme discharge of the dam break wave. The authors analyzed the methods of calculation prescribed in regulations and recommended by regulatory authorities. The calculation was made of the morphometric characteristics of the closure channel and extreme discharge of the dam break wave by various methods for specific objects, the comparison with expert estimates of these parameters. It is noted that the method, described in two regulations, has no physical justification, because according to it the size of closure channel and the parameters of breakthrough wave do not depend on the initial volume of water in the reservoir. The calculation method in the third regulation, does not take into account such factor as the time of erosion and the results are different at times with different specified step of erosion depth. This regulation is characterized by the use of empirical relations, which have a rather narrow range of use, and a lack of account of the relationship between the formation of the closure channel and the value of water discharge. Due to the lack of validity of the recommended calculation methods and large variation with expert estimates prescribed in the regulations, there is a need to create new alternative methods of calculation. This article discusses 2 such methods developed in various organizations. The first of them indirectly takes into account the material of the dam through calculated non-eroding velocity. The second one is based on the physical process of erosion, that is distinguishe it from others. As a test of the calculated values, there were used data on several recent catastrophic breakthroughs of groundwater dams. The comparison results allow us to conclude that alternative methods give greater accuracy. Based on the previous, can be done a preliminary conclusion about the need to revise existing regulations.