Design of a New Water Load for S-band 750 kW Continuous Wave High Power Klystron Used in EAST Tokamak

In order to test the klystrons operated at a frequency of 3.7 GHz in a continuous wave （CW） mode, a type of water load to absorb its power up to 750 kW is presented. The distilled water sealed with an RF ceramic window is used as the absorbent. At a frequency range of 70 MHz, the VSWR （Voltage Standing Wave Ratio） is below 1.2, and the rise in temperature of water is about 30 ℃ at the highest power level.

Effect of antidepressant treatment on water load test and cortisol changes in patients with functional dyspepsia

BACKGROUND： It has been demonstrated that patients with functional dyspepsia have experiences social life stress events, and accompanied by psychological disorders, mainly manifested as depression and anxiety.Mental factors can lead to excessive gastrointestinal consensual reaction, and result in different brain-gut axis disturbance, and then cause the gastrointestinal sensorimotor abnormality and endocrine changes.OBJECTIVE： To observe the effect of antidepressant treatment on the changes of water load and serum cortisol in patients with functional dyspepsia, and analyze the therapeutic mechanism.DESIGN： A comparative observation.SETTING： The First Affiliated Hospital o Zhengzhou University.PARTICIPANTS： Forty-five patients with functional dyspepsia accompanied by depression were selected from the Department of Gastroenterology, the First Affiliated Hospital of Zhengzhou University from July 2004 to July 2006, and they were 25 - 65 years of age, and their disease courses ranged 1 - 10 years. They were all accorded with the diagnostic standards for Rome Ⅱ functional dyspepsia functional dyspepsia. As the patients＇ will, they were divided into treatment group （n =30, 12 males and 18 females） and control group （n =15, 6 males and 9 females）, and there were no significant differences in the data between the two groups （P 〉 0.05）. The programs were discussed and agreed by the committee of medical ethics of the First Affiliated Hospital of Zhengzhou University. Informed contents were obtained from all the patients.METHODS： In the treatment group, the patients were treated with venlafaxine sustained release capsule （75 mg per day）, and those with sleep disorder were added by benzodiazepines （alprazolam）. In the control group, the patients were given routine treatments of antacid, prokinetics, etc. Before and after 8-week treatment, the following examinations were performed： ① The gastrointestinal symptoms were assessed according to the symptoms; ② The severity of depression was evaluated with Hamilton depression scale （HAMD）; ③The relaxation of proximal stomach was observed using water load test; ④ The serum level of cortisol was detected.MAIN OUTCOME MEASURES： ① Symptom score; ② HAMD score; ③ Water load amount; ④Serum level of cortisol.RESULTS： All the 45 patients were involved in the analysis of results. ① Symptom score： The scores of gastrointestinal symptoms were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ② HAMD scores： The scores of HAMD were decreased as compared with those before treatment in both the treatment group and control group （P 〈 0.05）. ③ Water load amount：The total effective rate was significantly higher in the treatment group than the control group （P 〈 0.05）. ④The serum levels of cortisol after treatment were significantly lower than those before treatment in the patients with severe gastrointestinal symptoms in the treatment group and control group （P 〈 0.05）.CONCLUSION： Antidepressants can normalize the cortisol level of patients with functional dyspepsia, and then decrease gastric sensitivity and ameliorates the receptive relaxation of proximal stomach, also increase the water load amount correspondingly, and finally control the gastrointestinal symptoms of functional dyspepsia.

Numerical Investigation of Green Water Loading on Flexible Structures Using Three-Step CFD-BEM-FEM Approach

In this paper,the effect of green water impact on a flexible structure is studied based on three-step computational fluid dynamics (CFD)-boundary element method (BEM)-fmite element method (FEM) approach.The impact due to shipping of water on the deck of the vessel is computed using commercial CFD software and used as an external force in coupled BEM-FEM solver.Other hydrodynamic forces such as radiation,diffraction,and Froude-Krylov forces acting on the structure are evaluated using 3D time domain panel method.To capture the structural responses such as bending moment and shear force,1 D finite element method is developed.Moreover,a direct integration scheme based on the Newmark-Beta method is employed to get the structural velocity,displacement,etc.,at each time step.To check the effect of the green water impact on the structure,a rectangular barge without forward speed is taken for the analysis.The influence is studied in terms of bending moment,shear force,etc.Results show that the effect of green water impact on the bow region can be severe in extreme seas and lead to various structural damages.Similarly,it is also verified that vessel motion affects green water loading significantly and therefore one must consider its effect while designing a vessel.

Effects of water intrusion and loading rate on mechanical properties of and crack propagation in coal–rock combinations

Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock combinations. Fifty-four coal–rock combinations were prepared and split equally into groups containing different moisture contents(dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal–rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal–rock combinations and laws of crack propagation.

THE CHANGE OF THE GENERAL FORM AND THE TRANSPORT OF THE WATER， LOAD AND SALT ABOUT THE NORTH－BRANCH OF THE CHANGJIANG RIVER MOUTH

陈宝冲ＴＨＥＣＨＡＮＧＥＯＦＴＨＥＧＥＮＥＲＡＬＦＯＲＭＡＮＤＴＨＥＴＲＡＮＳＰＯＲＴＯＦＴＨＥＷＡＴＥＲ，ＬＯＡＤＡＮＤＳＡＬＴＡＢＯＵＴＴＨＥＮＯＲＴＨ－ＢＲＡＮＣＨＯＦＴＨＥＣＨＡＮＧＪＩＡＮＧＲＩＶＥＲＭＯＵＴＨ￥ＣｈｅｎＢａｏｃｈｏｎｇ（Ｎ...

Rating Curve Estimation of Surface Water Quality Data Using LOADEST

Measurement of the nutrient concentrations in the stream is usually done on weekly, biweekly or monthly basis due to limited resources. There is need to estimate concentration and loads during the period when no data is available. The objectives of this study were to test the performance of a suite of regression models in predicting continuous water quality loading data and to determine systematic biases in the prediction. This study used the LOADEST model which includes several predefined regression models that specify the model form and complexity. Water quality data primarily nitrogen and phosphorus from five monitoring stations in the Neuse River Basin in North Carolina, USA were used in the development and analyses of rating curves. We found that LOADEST performed generally well in predicting loads and observation trends with general tendency/bias towards overestimation. Estimated Total Nitrogen (TN) varied from observation (“true” load) by -1% to 9%, but for the Total Phosphorus (TP) it ranged from -2% to 27%. Statistical evaluation using R2, Nash-Sutcliff Efficiency (NSE) and Partial Load Factor (PLF) showed a strong correlation in prediction.

Water Absorption and Chloride Ion Penetrability of Concrete Damaged by Freeze-thawing and Loading

In order to investigate water and chloride ion transport in damaged concrete, three types of concrete were prepared, freeze-thawing（F-T） cycling and compressive loading were adopted to induce damage to concrete. Ultrasonic pulse velocity technique was used for evaluating the damage degree of concrete, and the defects of damaged concrete were also detected by X-CT. Water absorption and chloride ion penetrability were used for describing the transport properties of damaged concrete. Effects of damage degree on the water absorption rate and chloride ion penetrability were investigated in detail and the relationships were also established. The results show that the water absorption of concrete makes various responses to damage degree due to the difference of concrete type and damage method. For same concrete with similar damage degree, the water absorption rate of F-T damaged concrete is usually larger than that of concrete damaged by loading. The chloride ion penetrability of damaged concrete increases linearly with increasing damage degree, which is more sensitive to damage degree if the original penetrability of sound concrete is higher.

Temporal Variations of Water Discharge and Sediment Load of Huanghe River,China

Based on the data from gauging stations,the changes in water discharge and sediment load of the Huanghe (Yellow)River were analyzed by using the empirical mode decomposition(EMD)method.The results show that the periodic oscillation of water discharge and sediment load of the Huanghe River occurs at the interannual,decadal,and multi-decadal scales,caused by the periodic oscillations of precipitation,and El Nio/Southern Oscillation(ENSO)affects water discharge by influencing precipitation distribution and contributes to periodic varations in precipitation and water discharge at interannual timescale.The water discharge and sediment load of the Huanghe River have decreased since the 1960s under the influence of precipitation and huamn activities,and human activities attribute more than precipitation to the reduction in the water discharge and sediment load,furthermore,water abstraction and water-soil conservation practices are the main causes of the decrease in water discharge and sediment load,respectively.The reduction in sediment load has directly impacted on the lower reaches of the Huanghe River and the river delta, causing considerable erosion of the river channel in the lower reaches since the 1970s along with River Delta changing siltation into erosion around 2000.

Wave-Induced Loads on Very Large FPSOs at Restricted Water Depth

The effects of water depth on the wave-induced vertical bending moment and shearing force on a very large FPSO are studied by experiments and computations for regular and irregular waves. The restricted water depth composite Green function is employed to develop a program for the computation of the hydrodynamic coefficients of the very large FPSO at shallow water. A three-segment model with 1∶100 scale is tested in the State Key Laboratory of Ocean Engineering at Shanghai Jiao Tong University for the verification of the numerical method. The experimental and computational results show that the water depth has a substantial effect on wave-induced loads. The wave-induced vertical loads increase with the decrease of water depth for shallow water. Especially, for ultra-shallow water these loads increase very evidently with the decrease of water depth. The long-term prediction values of wave-induced vertical loads increase with the decrease of the ratio of water depth to draught. The long-term prediction values of wave-induced vertical loads are about 8% larger than those for deep water when the ratio of water depth to draught is 3.0. However, water depth hardly affects the long-term prediction values of wave-induced loads when the ratio of water depth to draught is larger than 5.0.

Water quality, nutrient budget, and pollutant loads in Chinese mitten crab (Eriocheir sinensis) farms around East Taihu Lake

To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming.

Slamming and Green Water Loads on Bow-Flare Ship in Regular Head Waves Investigated by Hydroelasticity Theory and Experiment

With the development of ships towards large scale, high speed and light weight, ship hydroelastic responses and slamming strength issues are becoming increasingly important. In this paper, a time-domain nonlinear hydroelasticity theory is developed to predict ship motion and load responses in harsh regular waves.Hydrostatic restoring force, wave excitation force and radiation force are calculated on the instantaneously wetted body surface to consider the nonlinear effects caused by large amplitude motions of ship in steep waves. A twodimensional(2 D) generalized Wagner model and a one-dimensional(1 D) dam-breaking model are used to estimate the impact loads caused by bow flare slamming and green water on deck, respectively;the impact loads are coupled with the hydroelastic equation in time-domain. Moreover, segmented model tests are carried out in a towing tank to investigate the wave and slamming loads acting on the hull sailing in harsh regular head waves and also validate the numerical results.

Energy-Efficient Operation of Water Systems through Optimization of Load Power Reduction in Electricity Markets

Demand response(DR) is gaining more and more importance in the architecture of power systems in a context of flexible loads and high share of intermittent generation. Changes in electricity markets regulation in several countries have recently enabled an effective integration of DR mechanisms in power systems. Through its flexible components(pumps, tanks), drinking water systems are suitable candidates for energy-efficient DR mechanisms. However, these systems are often managed independently of power system operation for both economic and operational reasons. Indeed, a sufficient level of economic viability and water demands risk management are necessary for water utilities to integrate their flexibilities to power system operation. In this paper,we proposed a mathematical model for optimizing pump schedules in water systems while trading DR blocs in a spot power market during peak times. Uncertainties about water demands were considered in the mathematical model allowing to propose power reductions covering the potential risk of real-time water demand forecasting inaccuracy.Numerical results were discussed on a real water system in France, demonstrating both economic and ecological benefits.

Study on the subgrade deformation under high-speed train loading and water–soil interaction

It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy regions.This study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under high-speed train loading based on vehicle–track coupling dynamics.By using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the high-speed train loading,are studied.The main factors-the permeability coefficien and the porosity-influencin the subgrade deformation are investigated.The developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of water-rich soil.

Characteristics of Pore Water Pressure of Saturated Silt Under Wave Loading

The characteristics of dynamic stress in the seabed under wave loading are constant principal stress and continuous rotation of the principal stress direction. Cyclic triaxial-torsional coupling shear tests were pefformed on saturated silt by the hollow cylinder apparatus under different relative densities, deviator stress ratios and vibration frequencies to study the development of pore water pressure of the saturated silt under wave loading. It was found that the development of pore water pressure follows the trend of ＂fast - steady - drastic＂. The turning point from fast to steady stage is not affected by relative density and deviator stress ratio. However, the turning point from steady to drastic stage relies on relative density and deviator stress ratio. The vibration cycle for the liquefaction of saturated silt decreases with increasing deviator stress ratio and increases with relative density. The vibration cycle for the liquefaction of the saturated silt increases with vibration frequency and reaches a peak value, after which it decreases with increasing vibration frequency for the relative density of 70%. But the vibration cycle for the liquefaction of saturated silt increases with vibration frequency for the relative density of 30%. The development of pore water pressure of the saturated silt is influenced by relative density and vibration frequency.

Three-Dimensional Water Quality Model Based on FVCOM for Total Load Control Management in Guan River Estuary,Northern Jiangsu Province

Guan River Estuary and adjacent coastal area(GREC) suffer from serious pollution and eutrophicational problems over the recent years.Thus,reducing the land-based load through the national pollutant total load control program and developing hydrodynamic and water quality models that can simulate the complex circulation and water quality kinetics within the system,including longitudinal and lateral variations in nutrient and COD concentrations,is a matter of urgency.In this study,a three-dimensional,hydrodynamic,water quality model was developed in GREC,Northern Jiangsu Province.The complex three-dimensional hydrodynamics of GREC were modeled using the unstructured-grid,finite-volume,free-surface,primitive equation coastal ocean circulation model(FVCOM).The water quality model was adapted from the mesocosm nutrients dynamic model in the south Yellow Sea and considers eight compartments:dissolved inorganic nitrogen,soluble reactive phosphorus(SRP),phytoplankton,zooplankton,detritus,dissolved organic nitrogen(DON),dissolved organic phosphorus(DOP),and chemical oxygen demand.The hydrodynamic and water quality models were calibrated and confirmed for 2012 and 2013.A comparison of the model simulations with extensive dataset shows that the models accurately simulate the longitudinal distribution of the hydrodynamics and water quality.The model can be used for total load control management to improve water quality in this area.

A Preliminary Study on Mechanisms of Well Water Temperature Responses Based on the Modes of Stress Loading

Based on the studies of the predecessors, and contrasting the modes of stress loading with water level and water temperature response characteristics of a well-aquifer system, this paper draws a preliminary conclusion on the mechanisms of water temperature responses in a well caused by three modes of stress loading, i.e. gas escape, heat dispersion and cold water penetration mechanisms for elastic seismic wave stress loading; the fracture seepage mechanism for seismic wave stress loading and the hydrodynamic mechanism for earth tide stress loading and stress-dissipative heat mechanism for long period slow stress loading in the earthquake preparation stage. This paper illustrates the typical observation examples for each mode of stress loading and makes a preliminary study on their mechanisms.

Seawater Corrosion Fatigue of Welded Joints Under Random Variable Amplitude Loading

Offshore platforms are always subjected to wave action which is random variable amplitude cyclic loading. In order to simulate the stressing condition at the 'hot spot' of the tubular joints and the marine environment, random variable amplitude fatigue tests have been carried out on welded plate joints in sea water. The tests have been conducted under the conditions of loading frequency of 0.2 Hz/, stress ratio of -1, seawater temperature of about 20°C and cathodic protection with the potential about -850 mV, SCE. The test results have been compared with the seawater corrosion fatigue life under constant amplitude loading. Miner's linear cumulative damage summation rule has been used to predict the corrosion fatigue life under variable amplitude loading. The predicted life is in good agreement with the test data.

Impact of Grouting and Loading of Building Construction on the Water Level of Tangshan Mine Well

The water level rising rate of Tangshan mine well significantly accelerated in 2010,and the ascensional range was obviously higher than that of the same period in previous years.From the view of groundwater dynamics and loading effects,and based on the water pumping( pouring) water test model and semi-infinite elastic space theory model under uniform load,the effects of grouting and loading of nearby building construction on the well water level were analyzed. Results show that grouting at a distance of 200 ~ 700 m to the well,with amount of 2500m3 per day and duration of 270 d,can cause an 8 ~ 11 m rise of well water level; and loading of large-area building construction can cause about a 4m rise of well water level. Through the analysis of these factors,we find that the water level anomalous rising of Tangshan mine well was relevant to grouting and loading of the nearby building construction. This study provides a scientific basis for anomalous rising analysis of water level of Tangshan mine well.

进气歧管喷水对发动机燃烧性能的试验研究

为研究进气歧管喷水技术对汽油发动机热效率的提升潜力,基于一台研究型单缸汽油发动机,采用试验的手段对比研究了不同的喷水比例、不同的负荷工况及不同的压缩比下进气歧管喷水对发动机燃烧性能的影响。结果表明,采用进气歧管喷水技术可有效降低发动机的爆震趋势,随着喷水比例的增加,CA50逐渐提前,燃料的滞燃期及燃烧持续期增加,同时伴随着传热损失逐渐增加。相比于无喷水(w/o PWI)的结果,喷水的引入虽然导致未燃损失增加,但有利于排气能量损失大幅降低,最终反应到经济性的表现为热效率随着喷水比例的增大呈先增加后降低的趋势,油耗率的表现同热效率的结果相反;此时最佳的净指示热效率(GITE)为43.1%,相比于w/o PWI的结果升高了2.5%;最佳的净指示油耗率(GISFC)为197.9 g/(kW·h),相比于w/o PWI的结果降低了11.8 g/(kW·h)。高负荷运用喷水技术将达到更显著的热效率改善及油耗改善效果;同时,喷水技术的引入使得发动机高压缩比的应用成为可能。