This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The ...This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The evolutions of moisture properties under the influence of the westerly and summer southerly monsoon are examined using 5-yr multi-source measurements and ERA5 reanalysis data.Note that moisture consumption in this study is associated with clouds,precipitation,and diabatic heating.Compared to the midstream and downstream regions,the upstream region has less moisture,clouds,and precipitation,where the moisture is brought by the westerly.In early August,the vertical wet advection over this region becomes enhanced and generates more high clouds and precipitation.The midstream region has moisture carried by the westerly in June and by the southerly monsoon from July to August.The higher vertical wet advection maximum here forms more high clouds,with a precipitation peak in early July.The downstream region is mainly affected by the southerly-driven wet advection.The rich moisture and strong vertical wet advection here produce the most clouds and precipitation among the three regions,with a precipitation peak in late June.The height of the maximum moisture condensation is different between the midstream region(325 hPa)and the other two regions(375 hPa),due to the higher upward motion maximum in the midstream region.The diabatic heating structures show that stratiform clouds dominate the upstream region,stratiform clouds and deep convection co-exist in the midstream region,and deep convection systems characterize the downstream region.展开更多
Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring ...Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.展开更多
The interdependency among water, food, and energy (WEF) in the GCC countries is strongly and closely interlinked, and is intensifying as demand for resources increases with population growth and changing consumption p...The interdependency among water, food, and energy (WEF) in the GCC countries is strongly and closely interlinked, and is intensifying as demand for resources increases with population growth and changing consumption patterns, and are expected to be further compounded by the impacts of climate change. Therefore, integrated management of the three sectors is crucial to reduce trade-offs and build synergies among them. This paper presents a comprehensive framework to assess the WEF nexus in Kuwait as a representative case for the GCC countries. The framework consists of three main steps: 1) evaluating the influence of socio-economic development and climate change on water, energy, and food resources;2) generating scenario-based projections;and 3) conducting an extensive quantitative nexus analysis. The WEF interlinkages in Kuwait are modelled quantitatively using the Q-Nexus model, and current critical interdependencies are evaluated. Then, various WEF-Nexus scenarios were conducted for the year 2035 to explore the effects of management interventions in one sector on the other two sectors. The main findings are that per capita municipal water consumption is a major influencer on the WEF-nexus due to the heavy reliance on thermal desalination in municipal water supply in Kuwait, which is attributed to its energy intensity, financial cost, GHGs emissions, and environmental impacts on the marine and air environments. To reduce WEF trade-offs, mitigate risks, and build synergies among the three sectors, it is important to shift the current policy focus on supply-side management approach to the demand-side management and efficiency approaches.展开更多
Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops includi...Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops including spring wheat, oat, pea, flax and potato were examined. There was little difference in field water consumption among the crops during the growing season. WUE varied significantly in a range of 1. 347 -11.177kg · ha-1 · mm-1 among crops and 11.44% - 46.66% among previous crops. It was pointed out that the land equivalent ratio (LER) can be used as an index to evaluate the biological effects of crop rotation comprehensively. The 2-4 year crop rotation patterns with higher LER were estimated in the paper.展开更多
Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of til...Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE.展开更多
In arid areas,ecological degradation aroused by over-exploitation of fresh water,expansion of artificial oasis and shrinkage of natural oasis,has drawn attention of many scholars and officials.The water and ecological...In arid areas,ecological degradation aroused by over-exploitation of fresh water,expansion of artificial oasis and shrinkage of natural oasis,has drawn attention of many scholars and officials.The water and ecological footprints can be used to quantitatively evaluate the water consumption of social-economic activities and their influence on the eco-environments.In addition,increase of the water footprint indicates the expansion of artificial oasis,and the influence on the natural oasis could be reflected by the variation of the ecological footprint.This study was conducted to answer a scientific question that what is the quantitative relationship between the expansion of the artificial oasis and the degradation of the natural oasis in the arid environments of Xinjiang,China.Thus,based on the social-economic data,water consumption data and meteorological data during 2001–2015,we calculated the water and ecological footprints to express the human-related pressure exerted on the water resources and arid environments in Xinjiang(including 14 prefectures and cities),and explore the relationship between the water and ecological footprints and its mechanism by using the coupling analysis and Granger causality test.The results show that both the water and ecological footprints of Xinjiang increased significantly during 2001–2015,and the increasing rate of the ecological footprint was much faster than that of the water footprint.The coupling degree between the water and ecological footprints was relatively high at the temporal scale and varied at the spatial scale.Among the 14 prefectures and cities examined in Xinjiang,the greater social-economic development(such as in Karamay and Urumqi)was associated with the lower coupling degree between the two footprints.Increases in the water footprint will cause the ecological footprint to increase,such that a 1-unit increase in the consumption of water resources would lead to 2–3 units of ecological degradation.The quantitative relationship between the increases of the water and ecological footprints,together with the intensities of water consumption both in the natural and artificial oases of Tarim River Basin,have approved the fact that the formation and expansion of 1 unit of the artificial oasis would bring about the degradation of 2 units of the natural oasis.These conclusions not only provide a technical basis for sustainable development in Xinjiang,but also offer a theoretical guide and scientific information that could be used in similar arid areas around the world.展开更多
In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring...In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat (Triticum aestivum L.) as affected by water and phosphorus (P) supply. A factorial design was used with six treatments namely two water regimes (at 80–75% and 50–45% ifeld capacity (FC)) and three P supply rates (P1=0, P2=44 and P3=109 μg P g–1 soil). At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application (P3). The results indicated that rational or low P supply (80–75% of ifeld water capacity and 44 mg P kg–1 soil) should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.展开更多
Water resources are critical for the existence and development of oases in endorheic basins.Thus,to enable sustainable development,it is fundamentally important to understand how to allocate and use these resources in...Water resources are critical for the existence and development of oases in endorheic basins.Thus,to enable sustainable development,it is fundamentally important to understand how to allocate and use these resources in a reasonable way.We therefore simulated and analyzed changes in water consumption pattern within the Dunhuang Oasis of China under three scenarios using a system dynamic model that corresponds to different water consumption pattern.This was done to assess the impacts of regional water resource planning(comprehensive planning of the rational use of water resource and protection of ecosystem services in the Dunhuang Basin)on water consumption pattern within the Dunhuang Oasis.The first of these,Scenario 1,is a baseline in which the status quo is maintained,while Scenario 2 incorporates the comprehensive effects of agricultural water-saving irrigation measures with an inter-basin water diversion project,and Scenario 3 focuses on ecological rehabilitation.In the baseline Scenario 1,the total water consumption within the Dunhuang Oasis increased progressively while agricultural water consumption remained extremely high and threatened overall ecological security.In contrast,Scenario 2 would decrease agricultural water consumption by almost 5.30×10^7 m^3 following the implementation of water-saving practices.The additional water allocated from an inter-basin water diversion project would play an important role in alleviating ecological strain on the oasis.Finally,in Scenario 3,the total irrigated land must be decreased to 20.6×10^3 hm^2 by 2025 assuming that water supply for ecosystem restoration would be at least 50%of the total consumption.Although water resource planning plays a very important role in alleviating the ecological water crisis within the oasis,it is necessary to consider the suitable scale of oasis with regard to current water consumption pattern.展开更多
The increasing world population has forced excessive chemical fertilizer and irrigation to complete the global food demand,deteriorating the water quality and nutrient losses.Short-term studies do not compile the evid...The increasing world population has forced excessive chemical fertilizer and irrigation to complete the global food demand,deteriorating the water quality and nutrient losses.Short-term studies do not compile the evidences;therefore,the study aimed to identify the effectiveness of reduced doses of inorganic fertilizer and water-saving practices,hence,a six-year experiment(2015-2020)was conducted in China to address the knowledge gap.The experimental treatments were:farmer accustomed fertilization used as control(525:180:30 kg NPK ha^(-1)),fertilizer decrement(450:150:15 kg NPK ha^(-1)),fertilizer decrement+water-saving irrigation(450:150:15 kg NPK ha^(-1)),application of organic and inorganic fertilizer+water-saving irrigation(375:120:0 kg NPK ha^(-1)+4.5 tones organic fertilizer ha^(-1)),and application of controlled-release fertilizer(80:120:15 kg NPK ha^(-1)).Each treatment was replicated thrice following a randomized complete block design.The results achieved herein showed that control has the highest losses in the six-year study for total nitrogen(225.97 mg L^(-1)),total soluble nitrogen(121.58 mg L^(-1)),nitrate nitrogen(0.93 mg L^(-1)),total phosphorus(0.57 mg L^(-1)),and total soluble phosphorus(0.57 mg L^(-1))respectively.Reduced fertilizer and water application improved crop nutrient uptake,nitrogen concentration was significantly enhanced with organic and inorganic fertilizer+water-saving irrigation,P concentration was increased with fertilizer decrement+water-saving irrigation,and K concentration was improved with fertilizer decrement+water-saving irrigation.Hence,this study concludes that reduced inorganic fertilizer dose combined with water-saving practices is significantly helpful in reducing nutrient leaching losses and improving nutrient uptake and water pollution.Further studies are needed to explore the impacts of reduced fertilization and water-saving irrigation on leaching losses.The benefits at different climatic conditions,soil types,and fertilizer types with application methods are also a research gap.展开更多
ABSTRACT: The potential evapotranspiration of specific crops in the Changjiang Delta is calculated by using Pen-man-Monteith method, and an agricultural water consumption model in the area is developed on the basis of...ABSTRACT: The potential evapotranspiration of specific crops in the Changjiang Delta is calculated by using Pen-man-Monteith method, and an agricultural water consumption model in the area is developed on the basis of agricultural production situation. This model has higher precision compared with actual data and can reflect the actual status of agriculture water need. Considering the meteorological, hydrological, economical development situation of the Changjiang Delta, this paper calculates and analyzes the volumes of agricultural water consumption in 2000, 2010, 2030 and 2050 under different climate change conditions and different development speeds of urbanization in future. The result shows agriculture water demand increases with temperature rising and decreases obviously with cultivated area reducing. For the Changjiang Delta, the volume of agricultural water consumption in the future will less than that of present.展开更多
temperature and the diasolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn (Penaeus chinensis), giant tiger prawn (P. monodon) and giant freshwater prawn(Macrobrachium rosenbergii). There...temperature and the diasolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn (Penaeus chinensis), giant tiger prawn (P. monodon) and giant freshwater prawn(Macrobrachium rosenbergii). There is good correlation between the oxygen consumption rate (V, mg/g·h) of the above three prawn species and the water temperature, and dissolved oxygen. In the range of test temperature, V increased with water temperature and diassolved oxygen content. The V of the above three prawn species increased 0.085 mg/g·h, 0. 093 mg/g·h and 0. 08 mg/g·h respectively with each ℃ of rising temperature. The comatose point and stifling point of the juveniles rose obviously at unsuitable temperature.展开更多
The scarcity of water resources caused by the unique topography and uneven rainfall distribution in Hainan Island has become a major factor restricting local development. In order to provide effective and scientific r...The scarcity of water resources caused by the unique topography and uneven rainfall distribution in Hainan Island has become a major factor restricting local development. In order to provide effective and scientific reference basis for the overall water resource utilization status and solving this problem, this study calculated the water resource utilization situation of Hainan Island from 2017 to 2021 in detail using methods including water resource ecological footprint analysis. Furthermore, a spatial correlation analysis was conducted to examine the island's water resource utilization characteristics, and the driving factors behind the changes in water resource utilization over the past five years were analyzed using the LMDI model. The results show that:(1) During the study period, the water resource ecological footprint in Hainan Island exhibited a slow growth trend, while the ecological carrying capacity showed a downward tendency.The per capita ecological deficit of water resources remains relatively high, and the water consumption per 10 000 yuan GDP in the whole land continues to decrease, indicating that the overall pressure on water resource demand remains high with significant regional differences accompanied by the efficiency of water resource utilization steadily improving at the same time;(2) Agricultural water use accounts for the highest proportion in the entire water use structure, while ecological water use represents the smallest share, with a year-on-year increase, indicating that Hainan Island highlights the agricultural development and is increasingly conscious of the ecological environment;(3) Significant spatial differentiation in water resource utilization characteristics exists in Hainan Island, with the western region being a hot spot aggregation area for per capita water resource ecological footprint, per capita ecological carrying capacity of water resources, water consumption per 10 000 yuan GDP, while it is a cold spot cluster area for per capita ecological deficit of water resources. The opposite holds true for the eastern region of Hainan Island;(4) Economic and technological factors have a major impact on the changes in water resource ecological footprint within the designated area. Among them, economic factors drive the growth of the water resource ecological footprint in Hainan Island, and exacerbate local water resource consumption, while technological factors negatively contribute to the amount of water resource utilization in Hainan Island, indicating that advanced technology has improved water resource utilization efficiency and significantly reduced water resource consumption.展开更多
Our objective is to evaluate adequacy of water for consumption and irrigation. We collected nineteen water samples from 21 to 26, May 2017. Twenty-two physico-chemical and bacteriological parameters were taken into ac...Our objective is to evaluate adequacy of water for consumption and irrigation. We collected nineteen water samples from 21 to 26, May 2017. Twenty-two physico-chemical and bacteriological parameters were taken into account, electrical conductivity, pH, total hardness, bicarbonate, nitrates, sulfates, chlorides, calcium, sodium, magnesium, potassium, dissolved oxygen and biochemical oxygen demand, chemical oxygen demand, total coliforms, Escherichia Coli, and fecal coliforms. To evaluate water intended for consumption, average values measured parameters were compared to [1] for quality water drinking and we evaluated overall quality of water by means of simplified SEQ-Water grid. Concerning irrigation water, evaluation is based on interpretation of quality parameters of irrigation water that we have calculated;among these parameters we can mention the percentage of sodium, rate of sodium absorption, ratio of magnesium adsorption, residual sodium carbonate. Kelly ratio, Corrosivity ratio and Permeability Index. Results show that surface water is weakly mineralized compared to groundwater and presents a good chemical quality;however, it is slightly altered by presence of organic pollutants. The overall assessment of groundwater quality shows that about 47% of water sampled varies between average quality and very poor quality for consumption. This poor quality is mainly due to presence of nitrates in water, whose content sometimes exceeds the limit authorized by [1]. From a bacteriological point of view, germs of faecal origin such as Total Coliforms, Escherichia Coli and Faecal Coliforms contaminate all groundwater points sampled. They are of poor quality and unfit for human consumption without prior treatment. We also evaluated the quality of water used for irrigation using 6 parameters. The results show that all of our water points are suitable for irrigation, according to the values of CSR and Kelly ratio. The same is true for the permeability index, which shows that all samples fall into class I and II type to indicate their suitability for irrigation purposes. According to [2] all waters are excellent quality for agriculture;and for Richard diagram, 89.5% of waters are generally suitable for irrigation and 10% are generally not suitable for irrigation without prior dilution with low salinity water.展开更多
By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion...By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.展开更多
From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban fresh wat...From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban fresh water consumption was presented based on the theory of urban basic material consumption and the input-output method, which was utilized to calculate urban fresh water consumption of China, and to analyze its structural change and causes. The results show that the total urban fresh water consumption increased 561.7×109m3, and the proportion to the total national fresh water resources increased by 20 percentage points from 1952 to 2005. The proportion of direct and induced water consumption had been continuously rising, and it increased by 15 and 35 percentage points separately from 1952 to 2005, while the proportion of indirect water consumption decreased by 50 percentage points. Urban indirect water consumption was mainly related to urban grain, beef and mutton consumption, and urban induced water consumption had a close relationship with the amount of carbon emission per capita. Finally, some countermeasures were put forward to realize sustainable utilization of urban fresh water resources in China.展开更多
Water and nitrogen (N) management are key factors for sustainable pear production in many areas. Effects of integrated N fertilization and irrigation systems, rootstocks, and cultivars on pear (Pyrus communis) mineral...Water and nitrogen (N) management are key factors for sustainable pear production in many areas. Effects of integrated N fertilization and irrigation systems, rootstocks, and cultivars on pear (Pyrus communis) mineral nutrition, irrigation water and N consumption, and fruit productivity were investigated on a fine sandy loam soil at Hood River, Oregon from 2005 through 2007. Nitrogen application reduced to 80% of the current broadcast application rate and fertigated in five equal split applications could supply bearing pear trees with adequate N nutrition without reducing soil N reserves. Shifting from the broadcast of dry N fertilizer on soil surface and micro sprinkler irrigation system (BSS) to the split N fertigation and drip irrigation system (FDS) did not affect tree growth, fruit yield, or fruit size of pear. However, FDS produced more Bartlett fruit in color categories of 390 - 417 and 417 - 496 nm than BSS. Irrigation water consumption was reduced by 42.0% to 78.3%, but water use efficiency was enhanced by 51.0% to 264.2% with FDS relative to BSS. Split N fertigation and drip irrigation system may be used as an alternate N fertilization and irrigation system on bearing pear orchards to reduce irrigation water and N consumption in Hood River and other similar areas.展开更多
The Republic of Congo in the course of the last two decades has been marked by a strong demographic explosion. The increase of its population has been accompanied by a significant demand for drinking water. The Congol...The Republic of Congo in the course of the last two decades has been marked by a strong demographic explosion. The increase of its population has been accompanied by a significant demand for drinking water. The Congolese populations in order to meet their water needs, have recourse to rainwater, surface water and groundwater, because it is easy to access. The city of Brazzaville, political capital of the Republic of Congo, is also affected by this problem. The study carried out here aimed to assess the physicochemical and microbiological parameters of groundwater (wells, boreholes and springs) consumed by the populations of the Massissia district. In this work the physicochemical parameters below were evaluated: the pH, the conductivity, the hardness, the major ions, the undesirable substances as well as some toxic elements (Lead, Cadmium, Iron and Zinc) thanks to techniques of colorimetry, potentiometry and spectrophotometry. The main microbiological parameters determined are E. Coli, Staphylococcus, Total Germs, Total Coliforms, Yeasts and Molds. The physicochemical analyzes revealed that these waters are acidic with pH values between 5 and 6.5, the nitrate concentration evaluated between 50 mg/L and 60 mg/L, and a presence of the element Cadmium at values variants between 0.01 and 0.5 mg/L, values greater than the standard required by the WHO. Microbiological analyzes revealed bacteriological contamination by presence of E. coli in wells and boreholes whose origin is faecal contamination, the presence of yeasts and molds, staphylococcus, Total germs and Total coliforms and Ps Aeuginosis in all water points, making these waters a real danger for consumers.展开更多
We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with c...We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.展开更多
A comprehensive assessing method based on the principle of the gray system theory and gray relational grade analysis was put forward to optimize water consumption forecasting models. The method provides a better accur...A comprehensive assessing method based on the principle of the gray system theory and gray relational grade analysis was put forward to optimize water consumption forecasting models. The method provides a better accuracy for the assessment and the optimal selection of the water consumption forecasting models. The results show that the forecasting model built on this comprehensive assessing method presents better self-adaptability and accuracy in forecasting.展开更多
[Objective] The morphological characters of C.lasiocarpa were studied to find its morphological responses to different water regimes and growth stretagies through different water experiences.[Method] A seeding transpl...[Objective] The morphological characters of C.lasiocarpa were studied to find its morphological responses to different water regimes and growth stretagies through different water experiences.[Method] A seeding transplanting experiment with controlled water levels was set up,and the water level was changed at the middle of the season to compare water influence at the seeding stage and later growing period.C.lasiocarpa height,leaf length,leaf number,rhizome and adventitious roots length were measured at certain time througth the growing season.[Result] Results at the thriving season indicated that C.lasiocarpa height and leaf length in the experiment were similar to that in the field,but leaf number was higher under-5 cm water level and dry-wet alternate conditions than that in the field.At later growth period,height and leaf length under constant flooding(15cm) was significantly higher than that under other culture conditions,and also that of the field investigation;while the leaf number had a trend as-5 cm water level treatment>constant flooding>dry-wet alternate>field investigation.The height and leaf length were sensitive to seeding stage water effects,and leaf number sensitive to later influences.[Conclusion] Changes of water regimes in the growing season disturbed the growth of C.lasiocarpa,could accelerate or suspend its wilt,and modified the length of life history.展开更多
基金supported by The Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0105)the National Natural Science Foundation of China(91437221,91837204).
文摘This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The evolutions of moisture properties under the influence of the westerly and summer southerly monsoon are examined using 5-yr multi-source measurements and ERA5 reanalysis data.Note that moisture consumption in this study is associated with clouds,precipitation,and diabatic heating.Compared to the midstream and downstream regions,the upstream region has less moisture,clouds,and precipitation,where the moisture is brought by the westerly.In early August,the vertical wet advection over this region becomes enhanced and generates more high clouds and precipitation.The midstream region has moisture carried by the westerly in June and by the southerly monsoon from July to August.The higher vertical wet advection maximum here forms more high clouds,with a precipitation peak in early July.The downstream region is mainly affected by the southerly-driven wet advection.The rich moisture and strong vertical wet advection here produce the most clouds and precipitation among the three regions,with a precipitation peak in late June.The height of the maximum moisture condensation is different between the midstream region(325 hPa)and the other two regions(375 hPa),due to the higher upward motion maximum in the midstream region.The diabatic heating structures show that stratiform clouds dominate the upstream region,stratiform clouds and deep convection co-exist in the midstream region,and deep convection systems characterize the downstream region.
基金financial support from The University of Manchester to cover his PhD tuition fees for him to carry out this workChina National High-end Foreign Experts Recruitment Plan Project (G2023018001L) for partially supporting the work。
文摘Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.
文摘The interdependency among water, food, and energy (WEF) in the GCC countries is strongly and closely interlinked, and is intensifying as demand for resources increases with population growth and changing consumption patterns, and are expected to be further compounded by the impacts of climate change. Therefore, integrated management of the three sectors is crucial to reduce trade-offs and build synergies among them. This paper presents a comprehensive framework to assess the WEF nexus in Kuwait as a representative case for the GCC countries. The framework consists of three main steps: 1) evaluating the influence of socio-economic development and climate change on water, energy, and food resources;2) generating scenario-based projections;and 3) conducting an extensive quantitative nexus analysis. The WEF interlinkages in Kuwait are modelled quantitatively using the Q-Nexus model, and current critical interdependencies are evaluated. Then, various WEF-Nexus scenarios were conducted for the year 2035 to explore the effects of management interventions in one sector on the other two sectors. The main findings are that per capita municipal water consumption is a major influencer on the WEF-nexus due to the heavy reliance on thermal desalination in municipal water supply in Kuwait, which is attributed to its energy intensity, financial cost, GHGs emissions, and environmental impacts on the marine and air environments. To reduce WEF trade-offs, mitigate risks, and build synergies among the three sectors, it is important to shift the current policy focus on supply-side management approach to the demand-side management and efficiency approaches.
文摘Experiments were carried out in 1994 - 1998 to study crop rotation and its effects on crop water consumption characteristics of field with sandy chestnut soil in the Plateau of north Hebei Province. Five crops including spring wheat, oat, pea, flax and potato were examined. There was little difference in field water consumption among the crops during the growing season. WUE varied significantly in a range of 1. 347 -11.177kg · ha-1 · mm-1 among crops and 11.44% - 46.66% among previous crops. It was pointed out that the land equivalent ratio (LER) can be used as an index to evaluate the biological effects of crop rotation comprehensively. The 2-4 year crop rotation patterns with higher LER were estimated in the paper.
基金the supports from the National Natural Science Foundation of China (31171498 and 31401334)the Project of Technology System in Modern Wheat Industry, Ministry of Agriculture, China (CARS-3-1-19)
文摘Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efifciency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with ifve tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18%and 12.16, 14.75%higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88%for the 2008-2009 and 2009-2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No signiifcant difference was found between the WUE of the lfag leaf at the later iflling stage in the SRS and RS treatments, but the lfag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no signiifcant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efifcient measure to increase wheat yield and WUE.
基金supported by the National Key Technology Research and Development Program of China(2017YFC0404301,2016YFA0601602)the National Natural Science Foundation of China(51479209,51609260)
文摘In arid areas,ecological degradation aroused by over-exploitation of fresh water,expansion of artificial oasis and shrinkage of natural oasis,has drawn attention of many scholars and officials.The water and ecological footprints can be used to quantitatively evaluate the water consumption of social-economic activities and their influence on the eco-environments.In addition,increase of the water footprint indicates the expansion of artificial oasis,and the influence on the natural oasis could be reflected by the variation of the ecological footprint.This study was conducted to answer a scientific question that what is the quantitative relationship between the expansion of the artificial oasis and the degradation of the natural oasis in the arid environments of Xinjiang,China.Thus,based on the social-economic data,water consumption data and meteorological data during 2001–2015,we calculated the water and ecological footprints to express the human-related pressure exerted on the water resources and arid environments in Xinjiang(including 14 prefectures and cities),and explore the relationship between the water and ecological footprints and its mechanism by using the coupling analysis and Granger causality test.The results show that both the water and ecological footprints of Xinjiang increased significantly during 2001–2015,and the increasing rate of the ecological footprint was much faster than that of the water footprint.The coupling degree between the water and ecological footprints was relatively high at the temporal scale and varied at the spatial scale.Among the 14 prefectures and cities examined in Xinjiang,the greater social-economic development(such as in Karamay and Urumqi)was associated with the lower coupling degree between the two footprints.Increases in the water footprint will cause the ecological footprint to increase,such that a 1-unit increase in the consumption of water resources would lead to 2–3 units of ecological degradation.The quantitative relationship between the increases of the water and ecological footprints,together with the intensities of water consumption both in the natural and artificial oases of Tarim River Basin,have approved the fact that the formation and expansion of 1 unit of the artificial oasis would bring about the degradation of 2 units of the natural oasis.These conclusions not only provide a technical basis for sustainable development in Xinjiang,but also offer a theoretical guide and scientific information that could be used in similar arid areas around the world.
基金supported by the National Nature Science Foundation of China (31300328, 31200335, 31470496)the "111" Program from State Administration of Foreign Experts Affairs (SAFEA) & Ministry of Education (MOE), China (2007B051)+1 种基金the Fundamental Research Funds for the Central Universities, China (lzujbky-2012-97, lzujbky-2015-ct02, lzujbky-2016-86)the funding from the State Key Laboratory of Grassland Agro-ecosystem in Lanzhou University, China
文摘In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat (Triticum aestivum L.) as affected by water and phosphorus (P) supply. A factorial design was used with six treatments namely two water regimes (at 80–75% and 50–45% ifeld capacity (FC)) and three P supply rates (P1=0, P2=44 and P3=109 μg P g–1 soil). At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application (P3). The results indicated that rational or low P supply (80–75% of ifeld water capacity and 44 mg P kg–1 soil) should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.
基金supported by the National Nature Science Foundation of China (41701321)the Fundamental Research Funds for the Central Universities (2662015QD031)the 2014 Key Research Support Program of Central Government Higher Education Basic Research Founding (lzujbky-2014-269)
文摘Water resources are critical for the existence and development of oases in endorheic basins.Thus,to enable sustainable development,it is fundamentally important to understand how to allocate and use these resources in a reasonable way.We therefore simulated and analyzed changes in water consumption pattern within the Dunhuang Oasis of China under three scenarios using a system dynamic model that corresponds to different water consumption pattern.This was done to assess the impacts of regional water resource planning(comprehensive planning of the rational use of water resource and protection of ecosystem services in the Dunhuang Basin)on water consumption pattern within the Dunhuang Oasis.The first of these,Scenario 1,is a baseline in which the status quo is maintained,while Scenario 2 incorporates the comprehensive effects of agricultural water-saving irrigation measures with an inter-basin water diversion project,and Scenario 3 focuses on ecological rehabilitation.In the baseline Scenario 1,the total water consumption within the Dunhuang Oasis increased progressively while agricultural water consumption remained extremely high and threatened overall ecological security.In contrast,Scenario 2 would decrease agricultural water consumption by almost 5.30×10^7 m^3 following the implementation of water-saving practices.The additional water allocated from an inter-basin water diversion project would play an important role in alleviating ecological strain on the oasis.Finally,in Scenario 3,the total irrigated land must be decreased to 20.6×10^3 hm^2 by 2025 assuming that water supply for ecosystem restoration would be at least 50%of the total consumption.Although water resource planning plays a very important role in alleviating the ecological water crisis within the oasis,it is necessary to consider the suitable scale of oasis with regard to current water consumption pattern.
基金This study received funds from the National Natural Science Foundation of China[41361062]National Natural Science Foundation of China Joint Fund for Regional Innovation and Development[U20A20114]+1 种基金Natural Science Foundation of Ningxia Hui Autonomous Region[2022AAC03449]Station of Observation and Experiment National Agricultural Environment in Yinchuan,Ningxia,China[NAES091AE18].
文摘The increasing world population has forced excessive chemical fertilizer and irrigation to complete the global food demand,deteriorating the water quality and nutrient losses.Short-term studies do not compile the evidences;therefore,the study aimed to identify the effectiveness of reduced doses of inorganic fertilizer and water-saving practices,hence,a six-year experiment(2015-2020)was conducted in China to address the knowledge gap.The experimental treatments were:farmer accustomed fertilization used as control(525:180:30 kg NPK ha^(-1)),fertilizer decrement(450:150:15 kg NPK ha^(-1)),fertilizer decrement+water-saving irrigation(450:150:15 kg NPK ha^(-1)),application of organic and inorganic fertilizer+water-saving irrigation(375:120:0 kg NPK ha^(-1)+4.5 tones organic fertilizer ha^(-1)),and application of controlled-release fertilizer(80:120:15 kg NPK ha^(-1)).Each treatment was replicated thrice following a randomized complete block design.The results achieved herein showed that control has the highest losses in the six-year study for total nitrogen(225.97 mg L^(-1)),total soluble nitrogen(121.58 mg L^(-1)),nitrate nitrogen(0.93 mg L^(-1)),total phosphorus(0.57 mg L^(-1)),and total soluble phosphorus(0.57 mg L^(-1))respectively.Reduced fertilizer and water application improved crop nutrient uptake,nitrogen concentration was significantly enhanced with organic and inorganic fertilizer+water-saving irrigation,P concentration was increased with fertilizer decrement+water-saving irrigation,and K concentration was improved with fertilizer decrement+water-saving irrigation.Hence,this study concludes that reduced inorganic fertilizer dose combined with water-saving practices is significantly helpful in reducing nutrient leaching losses and improving nutrient uptake and water pollution.Further studies are needed to explore the impacts of reduced fertilization and water-saving irrigation on leaching losses.The benefits at different climatic conditions,soil types,and fertilizer types with application methods are also a research gap.
基金Under the auspices of the Doctorate Foundation Projects of China Education Committee(No.98028432).
文摘ABSTRACT: The potential evapotranspiration of specific crops in the Changjiang Delta is calculated by using Pen-man-Monteith method, and an agricultural water consumption model in the area is developed on the basis of agricultural production situation. This model has higher precision compared with actual data and can reflect the actual status of agriculture water need. Considering the meteorological, hydrological, economical development situation of the Changjiang Delta, this paper calculates and analyzes the volumes of agricultural water consumption in 2000, 2010, 2030 and 2050 under different climate change conditions and different development speeds of urbanization in future. The result shows agriculture water demand increases with temperature rising and decreases obviously with cultivated area reducing. For the Changjiang Delta, the volume of agricultural water consumption in the future will less than that of present.
文摘temperature and the diasolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn (Penaeus chinensis), giant tiger prawn (P. monodon) and giant freshwater prawn(Macrobrachium rosenbergii). There is good correlation between the oxygen consumption rate (V, mg/g·h) of the above three prawn species and the water temperature, and dissolved oxygen. In the range of test temperature, V increased with water temperature and diassolved oxygen content. The V of the above three prawn species increased 0.085 mg/g·h, 0. 093 mg/g·h and 0. 08 mg/g·h respectively with each ℃ of rising temperature. The comatose point and stifling point of the juveniles rose obviously at unsuitable temperature.
基金funded by Guangxi Karst Science and Technology Innovation Fund (KFKT2022001)China Geological Survey Program (DD20230416)。
文摘The scarcity of water resources caused by the unique topography and uneven rainfall distribution in Hainan Island has become a major factor restricting local development. In order to provide effective and scientific reference basis for the overall water resource utilization status and solving this problem, this study calculated the water resource utilization situation of Hainan Island from 2017 to 2021 in detail using methods including water resource ecological footprint analysis. Furthermore, a spatial correlation analysis was conducted to examine the island's water resource utilization characteristics, and the driving factors behind the changes in water resource utilization over the past five years were analyzed using the LMDI model. The results show that:(1) During the study period, the water resource ecological footprint in Hainan Island exhibited a slow growth trend, while the ecological carrying capacity showed a downward tendency.The per capita ecological deficit of water resources remains relatively high, and the water consumption per 10 000 yuan GDP in the whole land continues to decrease, indicating that the overall pressure on water resource demand remains high with significant regional differences accompanied by the efficiency of water resource utilization steadily improving at the same time;(2) Agricultural water use accounts for the highest proportion in the entire water use structure, while ecological water use represents the smallest share, with a year-on-year increase, indicating that Hainan Island highlights the agricultural development and is increasingly conscious of the ecological environment;(3) Significant spatial differentiation in water resource utilization characteristics exists in Hainan Island, with the western region being a hot spot aggregation area for per capita water resource ecological footprint, per capita ecological carrying capacity of water resources, water consumption per 10 000 yuan GDP, while it is a cold spot cluster area for per capita ecological deficit of water resources. The opposite holds true for the eastern region of Hainan Island;(4) Economic and technological factors have a major impact on the changes in water resource ecological footprint within the designated area. Among them, economic factors drive the growth of the water resource ecological footprint in Hainan Island, and exacerbate local water resource consumption, while technological factors negatively contribute to the amount of water resource utilization in Hainan Island, indicating that advanced technology has improved water resource utilization efficiency and significantly reduced water resource consumption.
文摘Our objective is to evaluate adequacy of water for consumption and irrigation. We collected nineteen water samples from 21 to 26, May 2017. Twenty-two physico-chemical and bacteriological parameters were taken into account, electrical conductivity, pH, total hardness, bicarbonate, nitrates, sulfates, chlorides, calcium, sodium, magnesium, potassium, dissolved oxygen and biochemical oxygen demand, chemical oxygen demand, total coliforms, Escherichia Coli, and fecal coliforms. To evaluate water intended for consumption, average values measured parameters were compared to [1] for quality water drinking and we evaluated overall quality of water by means of simplified SEQ-Water grid. Concerning irrigation water, evaluation is based on interpretation of quality parameters of irrigation water that we have calculated;among these parameters we can mention the percentage of sodium, rate of sodium absorption, ratio of magnesium adsorption, residual sodium carbonate. Kelly ratio, Corrosivity ratio and Permeability Index. Results show that surface water is weakly mineralized compared to groundwater and presents a good chemical quality;however, it is slightly altered by presence of organic pollutants. The overall assessment of groundwater quality shows that about 47% of water sampled varies between average quality and very poor quality for consumption. This poor quality is mainly due to presence of nitrates in water, whose content sometimes exceeds the limit authorized by [1]. From a bacteriological point of view, germs of faecal origin such as Total Coliforms, Escherichia Coli and Faecal Coliforms contaminate all groundwater points sampled. They are of poor quality and unfit for human consumption without prior treatment. We also evaluated the quality of water used for irrigation using 6 parameters. The results show that all of our water points are suitable for irrigation, according to the values of CSR and Kelly ratio. The same is true for the permeability index, which shows that all samples fall into class I and II type to indicate their suitability for irrigation purposes. According to [2] all waters are excellent quality for agriculture;and for Richard diagram, 89.5% of waters are generally suitable for irrigation and 10% are generally not suitable for irrigation without prior dilution with low salinity water.
文摘By employing the information-reshufflingmethod that integrates census data, precipitation dataand inquiry data of water consumption, this paperdiscusses 5 (water consumption coefficient of people’sliving) in allusion to different precipitation zones anddifferent periods of time. The study shows that 5-(water consumption coefficient of urban people’sliving), 5. (water consumption coefficient of ruralpeople’s living) and increase with time passing, andthe increasing extent of 5 is 1.84, 2.62, 2.84 and 2.68times respectively from the west to the east, whichresults from the total quantity of water resources andthe speed of urbanization. 5- and 5. of eachprecipitation zone increased with 5- increasing morequickly than 5., and the difference between the twoalso increased when time passed. In the past fifty years(1950-2000), the increasing extent of 5- was 1.71,2.96, 2.41 and 2.33 times respectively from the westto the east, in which 200-400mm precipitation zoneincreased more than others. Meanwhile the increasingextent of 5. is 1.55, 1.60, 1.53 and 1.64 timesrespectively from the west to the east with eachprecipitation zone increasing similarly. The change of5-is due to the speed of urbanization and the stabilityof water resources. This study provides basis forcalculating the water demand of people’s living andrevealing the impact of water demand of people’s livingon ecological drought in different zones.
基金Under the auspices of Key Project of National Natural Science Foundation of China (No. 40535026)
文摘From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban fresh water consumption was presented based on the theory of urban basic material consumption and the input-output method, which was utilized to calculate urban fresh water consumption of China, and to analyze its structural change and causes. The results show that the total urban fresh water consumption increased 561.7×109m3, and the proportion to the total national fresh water resources increased by 20 percentage points from 1952 to 2005. The proportion of direct and induced water consumption had been continuously rising, and it increased by 15 and 35 percentage points separately from 1952 to 2005, while the proportion of indirect water consumption decreased by 50 percentage points. Urban indirect water consumption was mainly related to urban grain, beef and mutton consumption, and urban induced water consumption had a close relationship with the amount of carbon emission per capita. Finally, some countermeasures were put forward to realize sustainable utilization of urban fresh water resources in China.
文摘Water and nitrogen (N) management are key factors for sustainable pear production in many areas. Effects of integrated N fertilization and irrigation systems, rootstocks, and cultivars on pear (Pyrus communis) mineral nutrition, irrigation water and N consumption, and fruit productivity were investigated on a fine sandy loam soil at Hood River, Oregon from 2005 through 2007. Nitrogen application reduced to 80% of the current broadcast application rate and fertigated in five equal split applications could supply bearing pear trees with adequate N nutrition without reducing soil N reserves. Shifting from the broadcast of dry N fertilizer on soil surface and micro sprinkler irrigation system (BSS) to the split N fertigation and drip irrigation system (FDS) did not affect tree growth, fruit yield, or fruit size of pear. However, FDS produced more Bartlett fruit in color categories of 390 - 417 and 417 - 496 nm than BSS. Irrigation water consumption was reduced by 42.0% to 78.3%, but water use efficiency was enhanced by 51.0% to 264.2% with FDS relative to BSS. Split N fertigation and drip irrigation system may be used as an alternate N fertilization and irrigation system on bearing pear orchards to reduce irrigation water and N consumption in Hood River and other similar areas.
文摘The Republic of Congo in the course of the last two decades has been marked by a strong demographic explosion. The increase of its population has been accompanied by a significant demand for drinking water. The Congolese populations in order to meet their water needs, have recourse to rainwater, surface water and groundwater, because it is easy to access. The city of Brazzaville, political capital of the Republic of Congo, is also affected by this problem. The study carried out here aimed to assess the physicochemical and microbiological parameters of groundwater (wells, boreholes and springs) consumed by the populations of the Massissia district. In this work the physicochemical parameters below were evaluated: the pH, the conductivity, the hardness, the major ions, the undesirable substances as well as some toxic elements (Lead, Cadmium, Iron and Zinc) thanks to techniques of colorimetry, potentiometry and spectrophotometry. The main microbiological parameters determined are E. Coli, Staphylococcus, Total Germs, Total Coliforms, Yeasts and Molds. The physicochemical analyzes revealed that these waters are acidic with pH values between 5 and 6.5, the nitrate concentration evaluated between 50 mg/L and 60 mg/L, and a presence of the element Cadmium at values variants between 0.01 and 0.5 mg/L, values greater than the standard required by the WHO. Microbiological analyzes revealed bacteriological contamination by presence of E. coli in wells and boreholes whose origin is faecal contamination, the presence of yeasts and molds, staphylococcus, Total germs and Total coliforms and Ps Aeuginosis in all water points, making these waters a real danger for consumers.
基金The support from both the Research Foundation for Returning Scholars of Chinathe China Postdoctoral Science Foundation
文摘We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.
基金Project(2003BA808A15-2-4) supported by the National Scientific and Technologies Key Task Program
文摘A comprehensive assessing method based on the principle of the gray system theory and gray relational grade analysis was put forward to optimize water consumption forecasting models. The method provides a better accuracy for the assessment and the optimal selection of the water consumption forecasting models. The results show that the forecasting model built on this comprehensive assessing method presents better self-adaptability and accuracy in forecasting.
基金Supported by the National Natural Science Foundation of China(41001030)the Natural Science Basic Research Plan in Shaanxi Province of China(2014JQ5194,2014JM7206)+1 种基金the Education Department of Shaanxi Province Special Research Project(12JK048415JK1386)
文摘[Objective] The morphological characters of C.lasiocarpa were studied to find its morphological responses to different water regimes and growth stretagies through different water experiences.[Method] A seeding transplanting experiment with controlled water levels was set up,and the water level was changed at the middle of the season to compare water influence at the seeding stage and later growing period.C.lasiocarpa height,leaf length,leaf number,rhizome and adventitious roots length were measured at certain time througth the growing season.[Result] Results at the thriving season indicated that C.lasiocarpa height and leaf length in the experiment were similar to that in the field,but leaf number was higher under-5 cm water level and dry-wet alternate conditions than that in the field.At later growth period,height and leaf length under constant flooding(15cm) was significantly higher than that under other culture conditions,and also that of the field investigation;while the leaf number had a trend as-5 cm water level treatment>constant flooding>dry-wet alternate>field investigation.The height and leaf length were sensitive to seeding stage water effects,and leaf number sensitive to later influences.[Conclusion] Changes of water regimes in the growing season disturbed the growth of C.lasiocarpa,could accelerate or suspend its wilt,and modified the length of life history.