Bimetallic Single‑Atom Catalysts for Water Splitting

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

Mechanism and control of water seepage of vertical feeding borehole for solid materials in backflling coal mining

To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.

Performance of a water hyacinth(Eichhornia crassipes)system in the treatment of wastewater from a duck farm and the effects of using water hyacinth as duck feed

Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.

Phosphorus accumulation and eutrophication in feed-supply freshwater fishponds

The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus （P） input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a （Chl-a） in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments. Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg. Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P （NH4Cl-P） and potentially labile P （NaOH-IP） were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyll-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds （12μg/L） 〈 fishponds without feed supply （24 μg/L） 〈 fishponds with feed supply （66 μg/L）. Linear correlations between concentrations of total P, Olsen-P, algal available P, water-soluble P and P concentration in saturation extracts in the sediments and dissolved P in the pond water indicated that there was a buffering action of the sediment constituents on the dissolved P.

Compensatory growth in hybrid tilapia (Oreochromis mossambicus×O. niloticus) reared in seawater, following restricted feeding

Hybrid tilapia weighing 7.71 g were reared in seawater at 24.0-29.0℃ for 8 weeks. The controls were fed to satiation twice a day throughout the experiment, whereas treatment groups were fed at 0.5%, 1.5% or 3.0% body weight per day for 4 weeks, and then to satiation for the remainder of the experiment. During the first 4-week period, there was a curvilinear relationship between growth rate and ration size. Fish fed 0.5% and 1.5% rations displayed compensatory growth response of 2 weeks duration during realimentation. The weight-adjusted growth rate of fish fed at 3% ration was not significantly different from that of the controls by the end of the experiment, when none of the treatment groups had caught up in body weight with the controls. Hyperphagia was observed for the first 2 weeks of realimenatation in fish previously fed at 3% ration, but persisted for the whole realimentation period in groups previously fed at 0.5% and 1.5% rations. None of the feed restricted groups showed improved digestibility, feed efficiency, or protein and energy retention efficiency.

Breeding and mass scale rearing of clownfish Amphiprion percula: feeding and rearing in brackishwater

Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid （276±22.3 eggs）] was observed when fish were fed live Acetes sp. rather than clam （204±16.4 eggs）, trash fish （155±12 eggs） and formulated feed （110±10 eggs）. The spawning rate was increased during September and October （water temperature, 28.74±0.55℃） on average of 2.4 spawning per month; and low spawning rate was in January （water temperature, 24.55±0.45℃） on average of I spawning per month. Among three light intensities （100, 500, and 900 1x） set to evaluate larval survival rate, larvae showed the highest survival rate （65.5%） at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat.

Effect of Feeding on Fresh(wet)Housefly Maggots(Musca domestica)with or without Artificial Diet on Water Quality and Growth Rates of African Catfish(Clarias gariepinus Burchell,1822)Fry under Laboratory Conditions

No or little information on the use fresh(wet)housefly maggots(Musca domestica)in African catfish(Clarias gariepinus)fry feeding.Therefore,this study was conducted to investigate the effect of feeding on fresh(wet)housefly maggots with or without artificial diet on water quality,growth performance,survival percentage and feed utilization of African catfish fry under laboratory conditions.Housefly maggots produced from a mixture of poultry droppings and foods wastes,it was used to replace artificial feed at 0,50 and 100% levels.Catfish were fed artificial diet alone(Feed 1),fresh(wet)housefly maggots alone(Feed 2),and 50% fresh housefly maggots with 50% artificial diet(Feed 3)were prepared and tested on triplicate groups of African catfish fry(initial weight of 0.25±0.02 g)for 60 days.Results showed that final weight(g/fish)was significantly(P≤0.05)higher in fish fed on feed 3(6.03±0.08),followed by fish fed feed 2(4.62±0.27),followed by fish fed feed 1(3.15±0.68).Specific growth rate(%/day)was also significantly higher in fish fed on feed 3(5.31±0.10),followed by fish fed feed 2(4.86±0.03),followed by fish fed feed 1(4.18±0.24).The same trend was observed with total weight gain,percentage weight gain,daily growth rate and relative growth rate.Feed intake and protein intake were significantly(P≤0.05)higher in fish fed on feed 3 and fish fed on feed 2,followed by fish fed feed 1.While,feed conversion ratio(FCR)and protein efficiency ratio were not significantly(P>0.05),but the improvement in FCR recorded in catfish fry fed feed 3 and feed 2 under the experimental conditions.Survival percentage was within the range 55-75%,with insignificant differences(P>0.05)among treatments.The water quality parameters such as temperature,pH,dissolved oxygen,total ammonia,nitrite and nitrate were not significantly(P>0.05)between the treatments and were tolerable for Catfish culture.Accordingly,use of the 50% fresh(wet)housefly maggots with 50% artificial diet in African catfish fry feeding had positive effect on growth performance and reduce of the feed cost.

Comparison of Potential Bio-Energy Feedstock Production and Water Quality Impacts Using a Modeling Approach

Cellulosic and agricultural bio-energy crops can be utilized as feedstock source for bio-fuels production and provide environmental benefits such as hydrology, water quality. This study compared potential feedstock yield and water quality benefit scenarios of six bio-energy crops: Miscanthus (Miscanthus-giganteus), Switchgrass (Panicum virgatum), Johnsongrass (Sorghum halepense), Alfalfa (Medicago sativa L.), Corn (Zea mays), and Soybean {Glycine max (L.) Merr.} at the watershed scale using Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated (1998 to 2002) and validated (2003 to 2010) using monthly measured USGS stream flow data. Model was further verified using available monthly sediment yield, and county level NASS corn and soybean yield data within the watershed. The long-term average annual potential feedstock yield as an alternative energy source was determined the greatest when growing Miscanthus grass scenario (21.9 Mg/ha) followed by Switchgrass (15.2 Mg/ha), Johnsongrass (12.1 Mg/ha), Alfalfa (7 Mg/ha), Corn (5.9 Mg/ha), and Soybean (2.35 Mg/ha). Model results determined the least amount of average annual sediment yield (1.1 Mg/ha) from the Miscanthus grass scenario and the greatest amount (12 Mg/ha) from the corn crop scenario. About 11% less annual average surface water flow from the watershed could be anticipated when converting land areas from soybean to Miscanthus grass. The results of this study suggested that growing Miscanthus grass in the UPRW would have the greatest potential feedstock yield and water quality benefits. The results of this study may help in developing future watershed management programs.

Feasibility Analysis of Back-Pressure Steam Feeding Water Pump for Direct Air-Cooled Unit

As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.

Surface warming patterns dominate the uncertainty in global water vapor plus lapse rate feedback

Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surface temperature increase. In projections by global climate models, it has been demonstrated that the geographical variation of sea surface temperature change brings significant uncertainties into atmospheric circulation and precipitation responses at regional scales. Here we show that the spatial pattern of surface warming is a major contributor to uncertainty in the combined water vapour-lapse rate feedback. This is demonstrated by computing the global-mean radiative effects of changes in air temperature and relative humidity simulated by 31 climate models using a methodology based on radiative kernels. Our results highlight the important contribution of regional climate change to the uncertainty in climate feedbacks, and identify the regions of the world where constraining surface warming patterns would be most effective for higher skill of climate projections.

On the Thermo Economical Optimization of Feed Water Heaters in Thermal Power Plants

A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum number of feed water heater and optimal area distribution among the feed water heaters for thermal power plants. The P1-P2 method is used in the present study, together with the thermoeconomic analyses of feed water heaters.

The Effect of Warm Water and Its Weak Negative Feedback on the Rapid Intensification of Typhoon Hato(2017)

Typhoon Hato (2017) went through a rapid intensification (RI) process before making landfall in Zhuhai,Guangdong Province, as the observational data shows. Within 24 hours, its minimum sea level pressure deepened by35hPa and its maximum sustained wind speed increased by 20m s-1. According to satellite observations, Hato encountered a large area of warm water and two warm core rings before the RI process, and the average sea surface temperature cooling (SSTC) induced by Hato was only around 0.73℃. Air-sea coupled simulations were implemented to investigate the specific impact of the warm water on its RI process. The results showed that the warm water played an important role by facilitating the RI process by around 20%. Sea surface temperature budget analysis showed that the SSTC induced by mixing mechanism was not obvious due to the warm water. Besides, the cold advection hardly caused any SSTC, either. Therefore, the SSTC induced by Hato was much weaker compared with that in general cases. The negative feedback between ocean and Hato was restrained and abundant heat and moisture were sufficiently supplied to Hato. The warm water helped heat flux increase by around 20%, too. Therefore, the warm water influenced the structure and the intensity of Hato. Although there might be other factors that also participated in the RI process, this study focused on air-sea interaction in tropical cyclone forecast and discussed the impact of warm water on the intensity and structure of a tropical cyclone.

Effect of Water Temperature on Feeding Rhythm in Common Carp (Cyprinus carpio haematopterus Temminck et Schlegel)

Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.

Water Intake and Utilization in Mithun (Bos frontalis):Effect of Environmental Temperature,Rearing System and Concentrate Feed Supplement

Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill Region （NEHR） of India. In a completely randomized design, twelve adult mithuns （B. frontalis） as per their sex and body weight were assigned in two different rearing systems （free grazing and free grazing with dry concentrate feed supplementation）, and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation （1.o kg and 2.0 kg dry concentrate feeds on green forage based diet） and in two different seasons （summer and winter）. It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption （per unit of body weight） was significantly （P 〈 0.05） higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption （drinking as well as performed water） was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly （P〈0.01） increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, therefore, be inferred that water intake by mithun varied with seasons, rearing systems and dry feed consumption. As far as the water nutrition is concerned, it is needed to give an attention while feeding mithun in summer with dry feed supplementation under semi-intensive system of rearing.

RELATION BETWEEN WATER TEMPERATURE, WATER EXCHANGE AMOUNT, FEED AND PRAWN DISEASE

High temperature is an important factor inducing bacterial disase of the prawn (Penaeus orientalis).Water temperature over 35℃ apparetly stopped tested baculovirus from multiplying. High contents of ammonia-nitrogen and nitrite-nitrogen poison the prawn’s body, weaken its physique and may induce and worsen the disease.

A novel integrated step-feed biofilm process for the treatment of decentralized domestic wastewater in rural areas of China

For wastewater treatment in rural areas, a novel three-stage step-feed wastewater treatment system, combined with a drop-aeration biofilm process, was tested in the laboratory to investigate its performance in removing suspended solids （SS）, chemical oxygen demand （COD）, NH4＋-N, total nitrogen （TN）, and total phosphorus （TP）. The removal rates of SS, COD and NH4＋-N were 90%, 80%, and 90% in efluent concentrations less than 10 mg/L, 50 mg/L and 8 mg/L, respectively. The TP removal rate was less satisfactory. The C/N ratio in the raw wastewater was often less than 3.5, and the removal efficiency of TN was therefore limited. A carbon-release batch experiment was carried out to measure the feasibility of enhancing denitrification at low influent C/N ratios. The result showed that the C/N could be over 9.0 in the supernatant. Polymerase chain reaction denaturing gradient gel electrophoresis technology was used to reveal the changes in the bacterial community during different stages of the integrated step-feed biofilm process. The results showed that banding patterns and the distribution of dominant bands for the same experimental period in different aerobic zones were similar. Phylogenetic analysis indicated that lanes 10, 11 and 12, which presented three aerobic zones at the same operation period, had the closest phylogenetic relationship among the lanes.

Composition, Structure and Functional Feeding of Aquatic Entomofauna in KodjobouéLake: Water Quality Assessment

The composition, structure and Functional Feeding Groups (FFGs) of aquatic insects were investigated in Kodjoboué lake (South-East of Côte d’Ivoire) to assess water quality. Four sites (K1 - K4) were sampled during eight campaigns. At each site aquatic insects were collected using a kick-net (25 × 20 cm, 500 μm mesh size). Environmental variables were also recorded during this period. Water was collected from each sampling site for nutrient (phosphorus, nitrate) analysis in laboratory. A total of 68 aquatic insect taxa belonging to six orders and 32 families were recorded during the study. Site K4, subject to intense agricultural activity, had the lower diversity and least balanced stand with the lowest values of Shannon-Weaver index, Pielou’s Evenness index and rarefied richness. The functional approach revealed five major FFGs: predators, scrapers, shredders, gatherers-collectors and filter-collectors. Among the different functional feeding groups, the percentage of predators was higher than that of other groups at all the sites. The P/R report indicated that our four sites are characterized as heterotrophic with K1 as the least heterotrophic. Focused Principal Component Analysis (FPCA) showed that parameters of water, like pH, dissolved oxygen, nitrate were statistically correlated with species abundance. The diversity and Functional Feeding Groups metrics of aquatic insects used to describe the state of Kodjoboué lake reveal its disturbed state.

Insights on advanced substrates for controllable fabrication of photoanodes toward efficient and stable photoelectrochemical water splitting

Conversion of solar energy into H_(2) by photoelectrochemical(PEC)water splitting is recognized as an ideal way to address the growing energy crisis and environmental issues.In a typical PEC cell,the construction of photoanodes is crucial to guarantee the high efficiency and stability of PEC reactions,which fundamentally rely on rationally designed semiconductors(as the active materials)and substrates(as the current collectors).In this review work,we start with a brief introduction of the roles of substrates in the PEC process.Then,we provide a systematic overview of representative strategies for the controlled fabrication of photoanodes on rationally designed substrates,including conductive glass,metal,sapphire,silicon,silicon carbide,and flexible substrates.Finally,some prospects concerning the challenges and research directions in this area are proposed.

Development of New Green Feed for Large Water Surface Ecological Fishery

In view of the fact that cages and bait are not allowed in large water surface aquiculture,1-2 kinds of new green feeds"plankton+microecologics"were developed to solve the problems of yield reduction,slow growth and difficulty in fishing of aquatic organisms caused by extensive mode.The new green feed is ecological,environmentally friendly and residue-free,which not only supplements nutrition but also meets the requirements of environmental protection.

Improving the nutritional values of yellow mealworm Tenebrio molitor(Coleoptera: Tenebrionidae) larvae as an animal feed ingredient: a review

Yellow mealworm larvae(YML;Tenebrio molitor) are considered as a valuable insect species for animal feed due to their high nutritional values and ability to grow under different substrates and rearing conditions. Advances in the understanding of entomophagy and animal nutrition over the past decades have propelled research areas toward testing multiple aspects of YML to exploit them better as animal feed sources. This review aims to summarize various approaches that could be exploited to maximize the nutritional values of YML as an animal feed ingredient. In addition, YML has the potential to be used as an antimicrobial or bioactive agent to improve animal health and immune function in production animals. The dynamics of the nutritional profile of YML can be influenced by multiple factors and should be taken into account when attempting to optimize the nutrient contents of YML as an animal feed ingredient. Specifically, the use of novel land-based and aquatic feeding resources, probiotics, and the exploitation of larval gut microbiomes as novel strategies can assist to maximize the nutritional potential of YML. Selection of relevant feed supplies, optimization of ambient conditions, the introduction of novel genetic selection procedures, and implementation of effective post-harvest processing may be required in the future to commercialize mealworm production. Furthermore, the use of appropriate agricultural practices and technological improvements within the mealworm production sector should be aimed at achieving both economic and environmental sustainability. The issues highlighted in this review could pave the way for future approaches to improve the nutritional value of YML.