Applications of Water Sensitivity In Situ Remediation at Saltwater-Freshwater Interface

Based on the laboratory experiments with the saltwater and freshwater replacing each other in the level sand column, taking the kaolin, illite, smectite, bivalent hydrargyrum ion （Hg^2＋） and ＂phenol （C6H5OH） as examples, this paper studies the applications of water sensitivity in situ remediation in saltwater-freshwater transition zone. In the water sensitivity process, the release and migration of clay minerals can make the hydraulic conductivity （HC） decrease and pollutants remove. A new type of low penetrable or impenetrable purdah can be built by adding clay minerals into the sand media to replace the underground concrete impenetrable wall to prevent seawater intrusion, and a number of the heavy metals and organic pollutants in the sand media can be removed by in situ remediation. The results show that the content of kaolin and illite influences the water sensitivity process slightly, and HC of the sand columns descends from 0.011 cm/s to 0.001 4 cm/s and 0.001 2 cm/s respectively even if the content reaches 12% （weight ratio, sic passim）. However, for smectite, HC descends sharply to about 1 × 10^-8 cm/s when its content reaches 4%, and no water can flow through the sand columns beyond 5%. The particle release and migration processes can remove the Hg^2＋ and C6HsOH out of the sand columns efficiently, the removing rate of Hg^2＋ is 31.68% when the freshwater and saltwater are filtered through the sand columns polluted by Hg^2＋, while it is 67.55% when the water sensitivity occurs. With the same method, the removing rates of C6H5OH under the fluid flow and water sensitivity are 55.71% and 43.43% respectively.

Research on Water Sensitivity and Velocity Sensitivity of Loose Sandstone Reservoir in China Offshore Oilfield

Aiming at the development characteristics of Bohai P oilfield, formation mechanism of reservoir damage was analyzed by mines of mineral composition, micro-pore structure, and seepage mechanism. Microscopic petrological observations and laboratory core experiments show that the content of clay minerals such as the Imon mixed layer and kaolinite is high with high porosity and good pore roar structure;the water sensitivity is medium to strong, The lower the salinity of injected water, the greater the drop in core permeability;the velocity-sensitive damage is strong, and permeability increases with the increase in flow velocity, and a large number of particles are observed in the produced fluid under the microscope. Aiming at the contradiction of velocity sensitivity between core permeability increase and the permeability decrease near the wellbore, the velocity sensitivity seepage model of “long-distance migration and blockage near the well” is proposed, and the permeability and formation distribution formula are deduced. The calculated value is close to the test value of actual pressure recovery test. The research results of water sensitivity and velocity sensitivity provide important guidance for Bohai P oilfield to improve production and absorption capacity and reservoir protection.

Effects of Periodical Soil Drying and Leaf Water Potential on the Sensitivity of Stomatal Response to Xylem ABA

The study on the changes of stomatal sensitivity in relation to xylem ABA during periodical soil drying and the effect of leaf water status on the stomatal sensitivity has confirmed that xylem ABA concentration is a good indicator of soil water status around roots and the relation between xylem ABA concentration and predawn leaf water potential remained constant during the three consecutive soil drying cycles based on the slopes of the fitted lines. The sensitivity of stomata to xylem ABA increased substantially as the soil drying cycles progressed, and the xylem ABA concentration needed to cause a 50% decrease of stomatal conductance was as low as 550 nmol/L in the next two soil drying cycle, as compared with the 750 nmol/L ABA in the first cycle of soil drying. The results using the split_root system showed that leaf water deficit significantly enhanced the stomatal response to xylem ABA and the xylem ABA concentration needed to cause a 50% decrease in stomatal conductance was 2 to 4 times smaller in the whole_root_drying treatment than those in the semi_root_drying treatment. These results suggested that the sensitivity of stomata to xylem ABA concentration is not a fixed characteristic.

Nitrogen, Phosphorus, and Potassium Interactive Effects for Improving Drought Resistance on Mung Bean Varieties

The planting areas of mung bean are mostly arid and semi-arid areas, and lack of irrigation conditions. Many studies have reported that fertilization can increase drought resistance. In our previous research, optimized nitrogen (N), phosphorus (P) and potassium (K) combined fertilization model was established in mung bean. In the present study, the optimal fertilization was conducted in pot trails, and mung bean varieties Bailv9 and Bailv11 were used as materials, while the four water regimes, and three fertilization ratios of F120 (optimal fertilization), F100 (conventional fertilization), F50 (half of conventional fertilization) treatments were set, to compare each fertilization ratio effects and non-fertilization condition under each water regimes respectively. Under different water conditions, the investigation of N, P, and K effects of optimal fertilization showed that the yield of Bailv9 was not sensitive to water stress and had strong drought resistance;their water sensitivity index and drought resistance coefficient were BaiLv9 as Di = 0.89 and DC = 0.79. The yield of Bailv11 was sensitive to water stress, and their drought resistance was weak;their water sensitivity index and drought resistance coefficient were BL11 Di = 1.76 DC = 0.59, and under different water treatment conditions, Bailv9 and Bailv11 all had the best yield and other related traits increase in the F120 fertilization mode compared with other fertilization and non-fertilization conditions, and the average yield increases were 31.56% and 28.08%, respectively. The pot trails conduct the drought stress treatments in mung bean varieties Bailv9, Bailv11, Bailv935 and Bailv985 to determine the function of NPK optimized fertilization for improving plants growth in drought stress condition. Compared with the mung bean varieties treated with F50, F100, and F120, the yield of Bailv9 increased by 56.20%, 81.27%, and 107.22%, respectively;compared with that of F0, the yield of Bailv11 increased by 10.18%, 19.42%, and 45.88%, respectively;Bailv935 increased by 26.52%, 61.90%, 74.16% respectively, and Bailv985 increased by 23.78%, 56.92%, 87.62% respectively. The significant performances of optimized fertilization were also verified in 20 mung bean varieties in our filed trails. The research establishes a theoretical basis for introducing the model into production practice in the next step.

Simple nonlinear model for the relationship between maize yield and cumulative water amount

Both the additive and multiplicative models of crop yield and water supply are polynomial equations, and the number of parameters increases linearly when the growing period is specified. However, interactions among multiple parameters occasionally lead to unreasonable estimations of certain parameters, which were water sensitivity coefficients but with negative value. Additionally, evapotranspiration must be measured as a model input. To facilitate the application of these models and overcome the aforementioned shortcomings, a simple model with only three parameters was derived in this paper based on certain general quantitative relations of crop yield （Y） and water supply （W）. The new model, Y/Y-W＊/（W＊＋w＊）, fits an S or a saturated curve of crop yield with the cumulative amount of water. Three parameters are related to biological factors： the yield potential （Y＊）, the water requirement to achieve half of the yield potential （half-yield water requirement, wh）, and the water sensitivity coefficient （k）. The model was validated with data from 24 maize lines obtained in the present study and 17 maize hybrids published by other authors. The results showed that the model was well fit to the data, and the normal root of the mean square error （NRMSE） values were 2.8 to 17.8% （average 7.2%） for the 24 maize lines and 2.7 to 12.7% （average 7.4%） for the 17 maize varieties. According to the present model, the maize water-sensitive stages in descending order were pollen shedding and silking, tasselling, jointing, initial grain filling, germination, middle grain filling, late grain filling, and end of grain filling. This sequence was consistent with actual observations in the maize field. The present model may be easily used to analyse the water use efficiency and drought tolerance of maize at specific stages.

ON THE RELATIONSHIP BETWEEN PRECIPITATION ANOMALIES IN THE FIRST RAINING SEASON (APRIL-JUNE) IN SOUTHERN CHINA AND SST OVER OFFSHORE WATERS IN CHINA

Precipitation anomalies in the first raining season of southern China were analyzed,with the suggestion that there are obvious interannual variation of peak values.In the raining season,the general tendency of precipitation is not obvious and the anomalous oscillation is multi-scale.Corresponding to years of more or less precipitation in the raining season,there are sharply opposite distribution across the nation in the simultaneous periods.In addition,by studying the distribution of correlation between anomalous precipitation in southern China in the first raining season and SSTA over offshore waters of China in the preceding period (June ～August of the previous year),a sensitive zone of waters has been found that has steady effect on the precipitation of southern China in the season.Discussions are also made of the sensitive period,its simultaneous SSTA and subsequent anomalous circulation field in relation to precipitation anomalies and simultaneous circulation field in the first raining season of southern China.In the last part of the work,relationship between the SSTA in the sensitive zone and global SSTA is analyzed.A possible mechanism by which SSTA in offshore Chinese waters affects the precipitation anomalies in the first raining season of southern China is put forward.

Failure mechanisms and risk mitigation of check dams on the Chinese Loess Plateau: A case study at the Gutun Gully

Loess is long-term aeolian dust deposition, characterized by loose structure, concentrated participle distribution and unstable mineral composition, and thus easy to cause extensive collapsibility and have general water sensitivity. To reveal the difference in water sensitivity between naturally intact(NI) loess and mechanically compacted(MC) loess used for the check dam, the transient water release and imbibition method(TRIM) was used to acquire the suction stress–expanded hydraulic characteristic curves for the NI and MC loess and explore possible approaches for formulating the potential of loess water sensitivity. Based on the Local Field of Safety(LFS) associated with slope stability, we constructed a finite element model of a check dam to depict its failure processes under different rainfall scenarios. The results revealed the strong water sensitivity in NI loess, while the MC loess retained a certain water-sensitive potential. This capacity depends on the ‘water sensitivity coefficient’ obtained from the suction-stress characteristic curve,which better presented the deformation potential of the two loess samples at different water content levels. In the context of LFS, we identified two failure patterns in the dam body that were involved in loess water sensitivity under hydromechanical conditions: rainfall erosion-induced shallow mudflow failure, and preferential-infiltration progressive failure. These patterns may provide new insights into dam-breakage mechanisms and potential chain effects of check dams on the Chinese Loess Plateau from the perspective of soil–water interactions, which is vital for predicting the position and timing of check dam failure, and mitigating risks.

Quantitative method to determine the regional drinking water odorant regulation goals based on odor sensitivity distribution:Illustrated using 2-MIB

Taste and odor （T/O） in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward WO. This study proposed a method to determine the regional drinking water odorant regulation goals （ORGs） based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisobomeol （2-MIB） by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA （flavor profile analysis） intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations.

Application of Novel Calix[4]arene Metal-free Sensitizers in Dye-sensitized Photoelectrochemical Cells for Water Splitting

A series of novel calix[4]arene metal-free dyes,featuring macrocyclic structure and unique conical confor mation,has been introduced into photoanode-based dye-sensitized electrochemical cell system as photosensitizers.The electrochemical properties of the corresponding sensitized photoanodes were systematically studied in the absence.presence of water oxidation catalyst(WOC).Furthermore,the visible-light-driven overall water-splitting reactions wero conducted by fully assembled devices,obtaining a performance trend of Calix-3>Calix-2 Calix-1.The correspondins device of Calix-3 exhibited the best photoactivity,giving an initial photocurrent density of ca.300 pA/cm^2,an IPEC peak value of ca.9.0%at 365 nm and a wide photo-respond band up to ca.620 nm.The best performance of Calix-3 an be attributed to its most effective light-harvesting ability,best ICT transition property,highest oxidation potentiaand thus best ability of activating WOC.This work offers an inspiration for the application of new-type effective metal-free sensitizers in photocatalytic water-splitting device.

Fifty Years of Water Sensitive Urban Design, Salisbury, South Australia

Australia has developed extensive policies and guidelines for the management of its water. The City of Salisbury, located within metropolitan Adelaide, South Australia, developed rapidly through urbanisation from the 1970s. Water sensitive urban design principles were adopted to maximise the use of the increased rim-off generated by urbanisation and ameliorate flood risk. Managed aquifer recharge was introduced for storing remediated low-salinity stormwater by aquifer storage and recovery （ASR） in a brackish aquiter for subsequent lrngatlon. Ibis paper outlines now a municipal government has progressively adopted principles of Water Sensitive Urban Design during its development within a framework of evolving national water policies. Salisbury＇s success with stormwater harvesting led to the formation of a pioneering w aterbusiness that includes linking projects from nine sites to provide a non-potable supply of 5 ×10^6 m^3 year. These installations hosted a number of applied research projects addressing well configuration, water quality, reliability and economics and facilitated the evaluation of its system as a potential potable water source. The evaluation showed that while untreated stonnwater contained contaminants, subsurface storage and end-use controls were sufficient to make recovered water sale for public open space irrigation, and with chlorination acceptable lbr third pipe supplies. Drinking water quality could be achieved by adding microfiltration, disinfection with UV and chlorination. The costs that would need to be expended to achieve drinking water safety standards were found to be considerably less than the cost of establishing dual pipe distribution systems. The full cost of supply was determined to be AUD$1.57 m ＂ for non-potable water for pubhc open space lrngatlon much cheaper than mares water, AUD $3.45 m at that time. Producing and storing potable water was found to cost AUDS1.96 to $2.24 m .

Mechanical Properties of Sustainable,Self-healing Porous Asphalt Concrete

Long lifetime sustainable porous asphalt concrete containing steel fibers was designed. The material is self healing in such a sense that some external stimulus is needed in the form of heating by induction energy. Steel wool was added to porous asphalt concrete to enhance its electrical conductivity and induction heating was applied to increase the temperature to heal the micro-cracks and repair the bonding between aggregate and binder. The main purpose of this paper is to examine the mechanical properties of this sustainable porous asphalt concrete including indirect tensile strength,work of fracture,particle loss resistance and water sensitivity. It is found that adding steel fibers to porous asphalt concrete to increase the healing performance also can improve its overall mechanical properties.

Influences of drought on the stability of an alpine meadow ecosystem

Drought plays a prominent role in affecting ecosystem stability and ecosystem productivity.Based on eddy covariance and climatic observations during 2012-2020,the Fisher discriminant analysis method was employed to accurately detect drought occurrences.Furthermore,the ecosystem water sensitivity and its resistance to drought were quantified to evaluate the ecosystem stability.The results showed that the alpine meadow suffered drought most frequently at the beginning of the growing seasons.However,drought during the peak growing seasons reduced the gross primary productivity(GPP)the most,by 30.5±15.2%.In the middle of the peak growing seasons,the ecosystem water sensitivity was weak,and thus,the resistance to drought was strong,which resulted in high ecosystem stability.At the beginning and end of the peak growing seasons,the ecosystem stability was relatively weak.Ecosystem stability was positively related to the corresponding multiyear average soil water content(SWC_(ave)).However,drought occurring during high SWC_(ave)periods led to larger reductions in GPP,which indicated that the inhibitory effects of drought on ecosystems were more dependent on the occurrence time of droughts than on ecosystem stability.

ONCOMELANIA'S ECO-HYDRAULIC PROPERTY AND ITS UTILIZATION

Oncomelania is the middle-parasitizeder of schistosome. The diffusion of Oncomelania with current will lead to the spread of schistosomiasis. River mechanics has been used in this paper. A systematic research with model test is engaged separately on Oncomelania hydrodynamic property. its sensitivity to water depth and velocity. Through this systematic experiment, a new thchnique of intake water without Oncomelania has been discovered. The technique can be widely applied to irrigation engineering.