Evaporation Ratio Research Articles

Collagen‐immobilized poly(ethylene terephthalate)‐g‐poly(vinyl alcohol) fibers prepared by electron‐beam co‐irradiation

ABSTRACTVinyl acetate was grafted onto poly(ethylene terephthalate) (PET) fibers under electron‐beam co‐irradiation. Then, the grafted products were hydrolyzed under HCl solution to obtain PET‐g‐poly(vinyl alcohol) (PVA) fibers. Afterward, to impart superior hydrophilicity and skin care, collagen was immobilized onto PET‐g‐PVA fibers with glutaraldehyde. The modified fabric was characterized in terms of moisture regain, wettability, and evaporation rate [Ev (%/h)]. The degree of alcoholysis of the grafting product was more than 90% in a 10% HCl solution at 100°C for 4 h, and its moisture regain was 1.4%. The modified PET fabric with collagen showed a shorter drip diffusion time and a higher wicking height than the unmodified PET and PET‐g‐PVA fabric before and after multiple washings. The evaporation ratio and Ev of the collagen‐immobilized PET fibers were far below those of the virgin PET fibers. The chemical structure, surface morphology, and element content of the product were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. This further certified that the collagen‐immobilized PET‐g‐PVA fiber was successfully prepared by the previous procedure. Furthermore, the PET–PVA–collagen fabric was capable of withstanding multiple washing cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40597.

Separation and recovery of zinc from copper-based alloy scraps under vacuum conditions

Separation and recovery process of zinc from scrap copper-based alloy was carried out under vacuum condition in a sublimation reactor. The factors affecting the evaporation ratio of copper-based alloy and the separation efficiency of zinc, such as heating temperature, residual gas pressure, vacuum evaporation time and the amount of scrap copper-based alloy were separately investigated. The experimental results revealed that zinc was successfully separated from the scrap copper-based alloy, where the evaporation ratio of copper-based alloy reached 18.43%. Namely, 96.09% by weight of zinc could be removed under the condition: residual gas pressure of 50 Pa, heating temperature of 1323 K and vacuum evaporation time of 90 min. If corresponding to the residual gas pressure 500 Pa, the evaporation ratio reached 18.17%, and 94.73% by weight of zinc could be removed under the following experimental conditions: temperature 1323 K, vacuum evaporation time 180 min. Meanwhile, the thermodynamics of vacuum sublimation and refining to recover zinc was analyzed and calculated.

Numerical simulation on the heat transfer characteristics during the bubble growth considering microlayer evaporation in nucleate boiling

In the previous studies, it was confirmed that there is a microlayer that forms between a growing bubble and the heat transfer surface in nucleate pooling boiling. The initial microlayer thickness was found to increase linearly with distance from the bubble inception site. Although a large amount of heat transport results from the evaporation of microlayer during the growth process of bubble, the quantitative degree of contribution of microlayer evaporation was not elucidated. In this study, numerical simulation was carried out on the two phase vapor-liquid flow induced by the growth of a single bubble in nucleate boiling by using the VOF (Volume of Fluid) method. The objective of this study is to clarify the heat transfer characteristics, especially the effect of evaporation of microlayer in nucleate pool boiling. A special model for simulating the microlayer evaporation was proposed, in which the microlayer was not considered in the calculation of flow field while its amount of evaporation was considered by applying the source term of the basic equations as an existence of virtual microlayer. Similar tendencies were shown between the calculation and experimental results on the variations of microlayer radius and bubble volume. The proportion of the amount of evaporation from microlayer to the volume of bubble is generally agreed with the previous results, which showed the ratio of microlayer evaporation to the total vapor volume change was approximately 40 percent.

Energy Budget on Various Land Use Areas Using Reanalysis Data in Florida

Energy budget is closely related to the hydrological cycle through evapotranspiration (ET) or latent heat. Hence, quantifying the energy budget on different land uses is critical for understanding the water budget and providing useful land use information for decision makers. However, traditional methods, including in situ measurements and model-only approaches, have deficiencies in data availability, and we have still not yet fully realized how well the energy budgets presented in reanalysis data sets. Therefore, in this study, North American regional reanalysis (NARR) data set from 1992 to 2002 were employed to investigate the energy budget on various land uses (lake, wetland, agriculture, forest, and urban) at a regional scale in Florida. The results showed that the lake and urban areas had high values of energy budget, evaporation, and low Bowen ratio, while the wetland areas have the opposite treads because of the lowest evaporation rate. During drought periods, Bowen ratio, surface temperature, and sensible heat were becoming higher than those of normal years conditions. Finally, by comparing with the observed data, we found NARR had better assimilation of precipitation observations and demonstrated the land use effects from the different coefficient of correlation relationships.

Thermodynamic and Experimental Studies of Chlorination Reaction of FeO-Cu<sub>2</sub>O System

Based on thermodynamic calculation results of Fe-Cu-Cl-O system by FACTSAGE software, chlorinate reaction of Fe-Cu-O melts was studied. The (CuCl)3(g) gas can stably exist under a certain condition. At 1273K, the high purity N2gas was used as the carrier gas to decrease the partial pressure of (CuCl)3(g) gas of FeO-Cu2O-CaCl2melt to promote the generation of of (CuCl)3(g). Thus Cu was transformed to chlorides and removed from the melt. Between 1123K and 1273K, after specimen of FeO-Cu2O-CaCl2system was sintered for 4h, the evaporation ratios of Cu and Fe were 55.45 % and 4.02 %, respectively. The results show that the chlorination reaction is an effective method to recycle the copper and iron.

Modeling interannual variability of seasonal evaporation and storage change based on the extended Budyko framework

[1] Long-term climate is the first-order control on mean annual water balance, and vegetation and the interactions between climate seasonality and soil water storage change have also been found to play important roles. The purpose of this paper is to extend the Budyko hypothesis to the seasonal scale and to develop a model for interannual variability of seasonal evaporation and storage change. A seasonal aridity index is defined as the ratio of potential evaporation to effective precipitation, where effective precipitation is the difference between rainfall and storage change. Correspondingly, evaporation ratio is defined as the ratio of evaporation to effective precipitation. A modified Turc-Pike equation with a horizontal shift is proposed to model interannual variability of seasonal evaporation ratio as a function of seasonal aridity index, which includes rainfall seasonality and soil water change. The performance of the seasonal water balance model is evaluated for 277 watersheds in the United States. The 99% of wet seasons and 90% of dry seasons have Nash-Sutcliffe efficiency coefficients larger than 0.5. The developed seasonal model can be applied for constructing long-term evaporation and storage change data when rainfall, potential evaporation, and runoff observations are available. On the other hand, vegetation affects seasonal water balance by controlling both evaporation and soil moisture dynamics. The correlation between NDVI and evaporation is strong particularly in wet seasons. However, the correlation between NDVI and the seasonal model parameters is only strong in dry seasons.

Vacuum Carbothermal Reduction for Treating Tin Anode Slime

In this work, a process of vacuum carbothermal reduction was proposed for treating tin anode slime containing antimony and lead. During vacuum carbothermal reduction, the antimony and lead were selectively removed simultaneously by reducing and decomposing the less volatile mixed oxide of lead and antimony into the more volatile Sb2O3 and PbO. Then the tin was enriched in the distilland and primarily present as SnO2. Crude tin was obtained via vacuum reduction of the residual SnO2. The results showed that 92.85% by weight of antimony and 99.58% by weight of lead could be removed at 850°C for 60 min with 4 wt.% of reductant and air flow rate at 400 mL/min corresponding to the residual gas pressure of 40 Pa–150 Pa. Under these conditions, an evaporation ratio of 52.7% was achieved. Crude tin with a tin content of 94.22 wt.% was obtained at temperature of 900°C, reduction time of 60 min, reductant dosage of 12.5 wt.%, and a residual gas pressure of 40 Pa–400 Pa. Correspondingly, the direct recovery of tin was 94.35%.

Study on Energy Exchange of Dry-Land Spring Maize Field in Loess Plateau

Dry-land spring maize is a main cultivated crop in North-West China. To explore the mechanism for changes of evapotranspiration and heat consumption in dry-land spring maize, eddy covariance technique was used to monitor the energy-exchange characteristics of the crop in Eastern Loess Plateau field. The results showed that the field-energy-balance ratio of dry-land spring maize is in the 0.75 - 1.0 range during non-rainfall daily noon (12:00 - 14:00). The Bowen ratio exhibited "L-type" trend during the total growth stages, namely, the highest Bowen ratio was at seedling stage with phase average 4.85 ± 1.42. The evaporation fraction showed a single peak trend in August, and the higher evaporation ratio met with more precipitation with average values 0.55 ± 0.06. The Bowen ratio and average evaporation fraction at the entire growth period were 1.78 ± 1.71 and 0.40 ± 0.18, respectively. About 40% of surface energy obtained from drought agro-ecosystem was used for evapotranspiration and heat consumption.

A late Holocene palaeoenvironmental record from Lake Tizong, northern Cameroon using diatom and carbon stable isotope analyses

A late Holocene record, based on diatom and stable carbon isotopes from Lake Tizong, northern Cameroon, provides a history of environmental changes over the last 4100 years. Several coarser sediment layers among which the two younger ones are of pyroclastic origin interrupt the fine clayey sediment of the core. The detailed chronology of the core supported by 24 radiocarbon 14C dates and proxies data results revealed an erosive phase registered in the sedimentary column from 2200 to 1500 cal BP. The diatom ecological groups suggest that between 4100 and 2800 cal yrs BP, the lake level was much higher than after corresponding to a relatively greater precipitation minus evaporation (P − E) ratio, as well as increased runoff in the lake catchment. These conditions were favourable to the development of C3 plants in the lake catchment as indicated by lower δ13C values and higher C/N ratios than after. This hydrological phase is also characterized by eutrophic, turbid and probably circum-neutral to alkaline waters. After this episode, higher δ13C values between 2800 and 2500 cal BP suggest increased water use efficiency of terrestrial plants and/or potentially more C4 plant debris input into the lake: an indication of savannas patches developing, due probably to changes in the rainfall distribution. Marked lake-level declines are recorded at 2500, 2200–2100, and at 1400–1000 cal yrs BP. These low-stands are characterized by higher inputs of windblown diatoms (up to 4.2%) than before, which confirms that the NE trade-winds were strengthening. This corresponds primarily to a reduction in the P − E ratio, but probably also to greater inter-annual or seasonal variability when drier periods or seasons became more prolonged and intense than previously. Consequently, savannas were maintained as suggested by relatively higher than before δ13C values, as well as independently supported by regional pollen data. After 1000 cal BP, the lake-level rose towards sub-modern conditions, with a deep neutral and eutrophic water column. Carbon stable isotopes suggest a reduction of organic matter input, while savannas were maintained despite the return to more humid conditions. The trends of climatic changes observed in the Lake Tizong reveal the variability in timing, magnitude and regional extent of known climatic events.

Study of crop coefficient and the ratio of soil evaporation to evapotranspiration in an irrigated maize field in an arid area of Yellow River Basin in China

A field experiment was conducted in a maize field in 2006 in an arid area of the Yellow River Basin in China. The daytime evapotranspiration (ETc) and soil evaporation beneath the maize canopy (Eg) were measured by Bowen ratio energy balance method and micro-lysimeters, respectively. The results showed that the total ETc during maize growth season was 696 mm, and the maximum values occurred at about 90–140 days after sowing. The crop coefficient (Kc), which was calculated from the ratio of ETc to reference evapotranspiration (ET0), was quite different from the values reported by other researchers in similar climate areas, with average values of 0.34, 0.47, 1.0 and 0.9 for initial, development, mid-season and late-season stages, respectively. High correlations between leaf area index (LAI) and average Kc for every 4 days were obtained. The total Eg was 201.4 mm with average values ranged from 0.92 to 2.05 for four growth stages of maize; and accounted for around 28.9 % of ETc. The ratio Eg/ETc showed high negative relationship with LAI. These results were very important in precise management of irrigation for maize in Yellow River Basin areas.

Evaporation behavior of low carbon ferromanganese alloy melt at reduced pressure

The distillation of an industrial Fe-Mn alloy at a high temperature and under a low pressure was suggested as an efficient method for manufacturing high purity manganese in our study. This study examined the evaporation behavior of a low carbon ferromanganese alloy melt at reduced pressure. The melt temperature, pressure, initial specific surface area of the melt and reaction time were considered as experimental variables. The evaporation ratio of manganese increased sharply in the initial reaction and remained relatively constant under various experimental conditions. The evaporation rate of manganese increased with an increasing temperature and the initial specific surface area of the melt and decreasing pressure. The activation energy of the manganese evaporation reaction decreased with a decreasing pressure. The initial specific surface area of the melt had a lesser effect than pressure. An empirical equation was derived for the rate of manganese evaporation from a low carbon ferromanganese alloy melt.

Analyzing potato response to irrigation and nitrogen regimes in a sub-tropical environment using SUBSTOR-Potato model

Increasing water scarcity and rising fertilizer cost warrant their judicious use in the world agriculture. It implies that management interventions should synchronize crop needs with soil supplies of these resources in the root zone to reduce probability of water and nutrient stresses and yield loss. This study examines the applicability of SUBSTOR-Potato model in analyzing potato response to irrigation and nitrogen regimes in a semi-arid sub-tropical environment of Punjab. In order to evaluate the model, database was generated by establishing a field experiment on potato (cv. Kufri Badshah) planted in mid-October on a sandy loam soil. Combinations of three irrigation regimes viz., irrigation water (IW) to pan evaporation (Ep) ratios of 0.8, 1.4 and 2.0 and four N rates viz., 0, 135, 180 and 225kgha−1 were randomized in a split-plot design with three replications. Half dose of N for a given rate was applied at planting and the rest half with a common irrigation 4 weeks after planting. The crop was managed for pest control by adopting local recommendations and harvested in end-January.Irrigation and fertilizer N had significant effects on tuber fresh yield, water use and N uptake. Performance of the SUBSTOR-Potato model was reasonable as indicated by close agreement of simulated crop phenology, biomass, water use, tuber yield and N uptake with the measured data. The normalized root mean square of deviations (RMSD) between simulated and measured values for harvest-time dry biomass and fresh tuber yield was 7.3 and 12.6%, while normalized RSMD for seasonal water use (ET+drainage) and total (tuber+haulm)N uptake was 12.4 and 19%. Simulation of tuber yield for independent data (2008–2009) was as good as for calibration data (2010–2011) giving confidence in the model. Scenario analysis based on historical weather data showed that mean potential tuber yield was 50.8tha−1 for October 1 planting that reduced to 41.8 and 37.8tha−1 for later (October 16 and October 31) plantings. The analysis also demonstrated that yield and ET-based water productivity (WPET) were greater on a sandy loam than a loamy sand soil for comparable irrigation and N regime. Interaction effects of irrigation and N on yield and ET indicated that irrigation response was greater in the presence of N. Greater initial soil water status reduced irrigation and N needs than with lower initial soil water for comparable tuber yield. Initial soil mineral-N also affected N and irrigation regime to achieve a given yield.

INITIAL WATER TEMPERATURE INFLUENCE ON THE THERMAL STATE EVAPORATING DROPLETS

The paper discusses modelling of water droplet heating and evaporation in dry air at different initial temperature. The effect of black body spectral radiation of air temperature to combined heat transfer in the semitransparent droplet has been evaluated. The effect of sprayed water temperature has been highlighted. Influence of water initial temperature to droplet heat and mass transfer during unsteady evaporation regime was evaluated by ratio of water initial and droplet equilibrium evaporation temperatures.DOI: http://dx.doi.org/10.5755/j01.mech.19.2.4160

Methodology for the physical and chemical exergetic analysis of steam boilers

This paper presents a framework of thermodynamic, energy and exergy, analyses of industrial steam boilers. Mass, energy, and exergy analysis were used to develop a methodology for evaluating thermodynamic properties, energy and exergy input and output resources in industrial steam boilers. Determined methods make available an analytic procedure for the physical and chemical exergetic analysis of steam boilers for appropriate applications. The energy and exergy efficiencies obtained for the entire boiler was 69.56% and 38.57% at standard reference state temperature of 25°C for an evaporation ratio of 12. Chemical exergy of the material streams was considered to offer a more comprehensive detail on energy and exergy resource allocation and losses of the processes in a steam boiler.

Conceptual evaluation of continental land-surface model behaviour

Continental land-surface models, such as the landscape component of the Australian Water Resources Assessment System (AWRA-L), aim to simulate the water balance over a wide variety of climates, land forms and land uses. To accommodate this range of hydrological conditions, model conceptualisation has to be flexible, while at the same time robust and parsimonious to allow for calibration using sparse data sets.In this study a Monte Carlo sensitivity analysis of the AWRA-L system is carried out as a step preceding calibration in which the hyperspace formed by parameters and initial conditions is explored using Latin Hypercube Sampling. The main goal is to test whether the model behaviour is in accordance with current understanding of Australian hydrology and to guide calibration. To visualise and analyse the high-dimensionality of the output space and the complex, non-linear interactions between processes and parameters, we used Self Organizing Maps, a non-parametric neural network.The results show that the main cause of non-linear model behaviour can be attributed to the ratio of rainfall over potential evaporation ratio, which determines which processes will dominate the water balance and the persistence of initial conditions. The model behaviour corresponds well to the current understanding of the hydrology of the Australian continent.

Dry matter production, seed yield and economics of French bean under different cropping system and irrigation regimes

A field experiment was conducted during rabi seasons of 2004–2005 and 2005–2006 at the Indian Agricultural Research Institute, New Delhi, to evaluate the effects of cropping systems and irrigation regimes on dry matter production, seed yield and economics of French bean. The treatments were comprised of five irrigation schedules (irrigation at critical stages of potato, irrigation at critical stages of French bean and irrigation at 0.8, 1.2 and 1.6 irrigation water/cumulative pan evaporation ratio (IW/CPE ratio) in main plots with two cropping systems (sole French bean and French bean intercropped with potato in 3:2 row ratio) as sub plot treatments replicated thrice in a split plot design. Sole French bean produced significantly higher dry matter, more pods/plant, more seeds/pod, higher seed and straw yields as compared with intercropped. The results revealed that all irrigation schedules recorded similar dry matter accumulation, except at IW/CPE ratio of 0.8. Irrigation at IW/CPE ratio of 1.2 and 1.6 recorded production of more pods/plant and seeds/pod than 0.8 IW/CPE ratio. Irrigation at 0.8 IW/CPE ratio had the lowest 100 seed weight and seed yield than other irrigation treatments.

Effect of the defect on photoluminescence property of Al-coated ZnO nanostructures

The room-temperature photoluminescence (PL) spectra of hydrothermal grown ZnO film and nanowires coated with Al are investigated, which exhibit much less UV emission enhancement ratio as against that of nanowires fabricated by thermal evaporation method. A model is suggested at last to interpret the experimental results considering the influence of the defect on the contact property between metal and ZnO, which is further evidenced by the weak PL enhancement ratio of thermal evaporation grown ZnO nanowires with H(2)O(2) treatment.

Similarity of climate control on base flow and perennial stream density in the Budyko framework

Abstract. Connection between perennial stream and base flow at the mean annual scale exists since one of the hydrologic functions of perennial stream is to deliver runoff even in low flow seasons. The partitioning of precipitation into runoff and evaporation at the mean annual scale, on the first order, is captured by the ratio of potential evaporation to precipitation (EP/P called climate aridity index) based on Budyko hypothesis. Perennial stream density (DP), which is obtained from the high resolution National Hydrography Dataset, for 185 watersheds declines monotonically with climate aridity index, and an inversely proportional function is proposed to model the relationship between DP and EP/P. The monotonic trend of perennial stream density reconciles with the Abrahams curve since perennial stream density is only a small portion of the total drainage density. The correlation coefficient between the ratio of base flow to precipitation (Qb/P), which follows a complementary Budyko type curve and perennial stream density is found to be 0.74. The similarity between Qb/P and DP reveals the co-evolution between water balance and perennial stream network.

Transpiration of maize under different cultivation patterns in the Loess Tableland

采用基于热平衡法的茎流计对黄土塬区两种栽培模式下(传统模式Ⅰ和改进模式Ⅱ)玉米(Zea mays L.)的茎流变化进行连续监测, 并结合试验区自动气象站同步测定的太阳辐射、气温、相对湿度和风速等气象因子, 分析了黄土塬区不同栽培模式下玉米蒸腾耗水规律及其与气象因子的关系。结果表明: 两种模式下玉米植株的茎流速率都表现出与太阳辐射同步的昼夜变化规律, 且模式Ⅰ植株茎流速率大于模式Ⅱ植株茎流速率; 玉米的日茎流量在抽雄期达到最大并且均随生育期的推移逐渐变小, 这与植株叶面积指数的变化基本一致; 从抽雄期到蜡熟期, 模式Ⅰ和模式Ⅱ玉米群体叶面蒸腾量分别为115.18 mm和119.47 mm, 棵间蒸发量模式Ⅱ(39.41 mm)较模式Ⅰ(64.81 mm)减少了39.2%, 表明改进模式优化了玉米群体的蒸腾蒸发比率, 有利于玉米水分利用效率的提高。除风速外, 两种模式下植株的日茎流速率与太阳辐射、水汽压差、空气温度和相对湿度均存在较好的相关关系, 达到极显著水平。

兴安落叶松针叶解剖结构变化及其光合能力对气候变化的适应性

Leaf anatomy,being susceptible to environmental factors,is closely related to physiological functions of the leaf, and also reflects responses and adaptation of the tree to environmental changes. Changes in leaf anatomical structure are bound to change the physiological functions of trees. The same species growing in heterogeneous environment for a long time through natural selection and adaptation will result in variations in morphological and physiological characteristics,forming distinctive geographic populations. In addition,Matrix subjected to environmental stress will affect its offspring growth, developmental and physiological characteristics. Therefore,to understand how the morphological structure of leaves respond and adapt to environmental changes is essential for exploring the response and adaptation mechanism of plants to environmental changes. Dahurian larch( Larix gmelinii Rupr.) is a dominant tree species in boreal forest in China,mainly distributed in northeast China,but going further climate changes may change its existing distribution. There are few studies to distinguish short-term responses of leaf anatomy and physiology from their potential long-term adaptation to climate changes in field. In this study,we conducted a common garden experiment that included six provenances of Dahurian larch with different climate and site conditions with three replicate trees each provenance. The trees were 32 years old,seeded in 1980,and transplanted in 1983 at identical site and climate conditions. We measured leaf anatomical parameters using paraffin section method( i. e.,total leaf thickness,leaf adaxial epidermis cells thickness,leaf abaxial epidermis cells thickness,leaf adaxial mesophyll cells thickness,leaf abaxial mesophyll cells thickness,leaf vascular bundle tissue thickness,leaf endoderm cells thickness,leaf transporting tissue thickness,leaf epidermis cells thickness,leaf mesophyll cells thickness,and photosynthetic physiology( i. e.,photosynthetic capacity [P max-a ],stomatal conductance [g s ],water use efficiency [WUE]) in order to address the question of whether leaf anatomical structure adapts to climate changes and consequently results in physiological adaptation. The results showed that the thickness of epidermis cells,mesophyll cells, transmission tissue cells,vascular cells and endothelial cells,and the total thickness of the needles differed significantly among the provenances( P 0. 05). There was a significant difference in the proportion of thickness of each anatomical part. The thickness of mesophyll cell accounted for the largest proportion,with an average proportion ranging from 38. 4% to 43. 3%. The thickness of mesophyll cells was positively correlated( P0. 05) with P max-a,g s,and WUE. The thickness of mesophyll cells and epidermal cells,the total thickness of the needles,and the proportions of thickness of mesophyll cells or epidermal cells in the total thickness of the needle were all positively correlated with the aridity index( the ratio of mean annual evaporation to mean annual precipitation) at the origins of the provenances. These results suggest that needles of the Dahurian larch trees from different provenances alter their anatomical structures significantly due to adaptation to local climate conditions,and accordingly change their physiological functions such as photosynthesis and water use efficiency.