A study on the consumptive use of water by kharif rice at Canning (West Bengal)

Based on the data for the period from 1977 to 1992 during the kharif season. mean weekly evapotranspiration (ET) and its contribution for different phases to total evaporative loss have been worked out for kharif rice at Canning. The evapotranspiration-evaporation ratio (ET/EP) and crop coefficient (Kc) have been round to attain peak values during the flowering stage. A relationship between ET/EP and number of days from transplanting has been developed and this relationship helps in detero\ining ET from a knowledge of EP and date of transplanting. Ratio of evapotranspiration to total shortwave radiation (ET/R2) which represents the combined effect of energy balance components. also reaches its peak value during the flowering stage. Among the four different energy summation indices. the potential evapotranspiration seems to be a better parameter for identification of growth stages of the crop. Water use efficiency of kharif rice shows significant year-to-year variations.

The Holocene lake-evaporation history of the afro-alpine Lake Garba Guracha in the Bale Mountains, Ethiopia, based on δ18O records of sugar biomarker and diatoms

In eastern Africa, there are few long, high-quality records of environmental change at high altitudes, inhibiting a broader understanding of regional climate change. We investigated a Holocene lacustrine sediment archive from Lake Garba Guracha, Bale Mountains, Ethiopia, (3,950 m asl), and reconstructed high-altitude lake evaporation history using δ18O records derived from the analysis of compound-specific sugar biomarkers and diatoms. The δ18Odiatom and δ18Ofuc records are clearly correlated and reveal similar ranges (7.9‰ and 7.1‰, respectively). The lowest δ18O values occurred between 10–7 cal ka BP and were followed by a continuous shift towards more positive δ18O values. Due to the aquatic origin of the sugar biomarker and similar trends of δ18Odiatom, we suggest that our lacustrine δ18Ofuc record reflects δ18Olake water. Therefore, without completely excluding the influence of the ‘amount-effect’ and the ‘source-effect’, we interpret our record to reflect primarily the precipitation-to-evaporation ratio (P/E). We conclude that precipitation increased at the beginning of the Holocene, leading to an overflowing lake between ca. 10 and ca. 8 cal ka BP, indicated by low δ18Olake water values, which are interpreted as reduced evaporative enrichment. This is followed by a continuous trend towards drier conditions, indicating at least a seasonally closed lake system.

Exploring the role of soil storage capacity for explaining deviations from the Budyko curve using a simple water balance model

The Budyko curve is a widely used framework for predicting the steady-state water balance –solely based on the hydro-climatic setting of river basins. While this framework has been tested and verified across a wide range of climates and settings around the globe, numerous catchments have been reported to considerably deviate from the predicted behavior. Here, we hypothesize that storage capacity and field capacity of the root zone are important controls of the water limitation of evapotranspiration and thus deviations of the mean annual water balance from the Budyko curve. For testing our hypothesis, we selected 16 catchments of different climatic settings and varied the corresponding parameters of a simple water balance model that was previously calibrated against long-term data and investigated the corresponding variations of the simulated water balance in the Budyko space. We found that total soil storage capacity –by controlling water availability and limitation of evapotranspiration– explains deviations of the evaporation ratio (EVR) from the Budyko curve. Similarly, however to a lesser extent, the evaporation ratio showed sensitivity to alterations of the field capacity. In most cases, the parameter variations generated evaporation ratios enveloping the Budyko curve. The distinct soil storage volumes that matched the Budyko curve clustered at a normalized storage capacity equivalent to 5–15 % of mean annual precipitation. The second, capillarity-related soil parameter clustered at around 0.6–0.8, which is in line with its hydropedological interpretation. A simultaneous variation of both parameters provided additional insights into the interrelation of both parameters and their joint control on offsets from the Budyko curve. Here we found three different sensitivity patterns and we conclude the study with a reflection relating these offsets to the concept of catchment coevolution. The results of this study could also be useful to facilitate evaluation of the water balance in data-scarce regions, as they help constrain parameterizations for hydrological models a priori using the Budyko curve as a predictor.

A set of methods to quantitatively evaluate the below-cloud evaporation effect on precipitation isotopic composition: a case study in a city located in the semi-arid regions of Chinese Loess Plateau

Below-cloud evaporation effect heavily alters the initial precipitation isotopic composition, especially in the arid and semi-arid regions, and leads to misinterpreting the isotopic signal. To correctly explore the information contained in the precipitation isotopes, the first step is to qualitatively analyze the falling raindrops encountered below-cloud processes, and then to quantitatively compute the below-cloud evaporation ratio of raindrops. Here, based on two-year precipitation and water vapor isotopic observations in Xi'an, we systematically evaluated the variations of precipitation and water vapor isotopes caused by the below-cloud evaporation effect. Our results suggest that the equilibrium method could be successfully used to predict the ground-level water vapor isotopic composition in semi-arid climates, especially for the winter data. Moreover, by using △d△δ-diagram, our data showed that evaporation is the mainly happened below-cloud process of raindrops, while snowfall samples retained the initial cloud signal because of less isotopic exchange between vapor and solid phases. In terms of meteorological factors, both temperature, relative humidity, and precipitation amount affect the intensity of below-cloud evaporation. In arid and semi-arid regions, the below-cloud evaporation ratio computed by the mass conservation equation would be overestimated relative to the isotopic method, while relative humidity is the most sensitive parameter in computing the remaining fraction of evaporation. In the Chinese Loess Plateau (CLP) city, raindrops are weakly evaporated in autumn and winter, and heavily evaporated in spring and summer, and in the meantime, the evaporation intensity is related to the local relative humidity. Our work sets an integrated and effective method to evaluate the below-cloud evaporation effect, and it will improve our understanding of the information contained in precipitation isotopic signals.

Morphological, Optical, and Electrical Properties of p-Type Nickel Oxide Thin Films by Nonvacuum Deposition

In this study, a p-type 2 at% lithium-doped nickel oxide (abbreviation L2NiO) solution was prepared using Ni(NO3)2·6H2O, and LiNO3·L2NiO thin films were deposited using an atomizer by spraying the L2NiO solution onto a glass substrate. The sprayed specimen was heated at a low temperature (140 °C) and annealed at different high temperatures and times. This method can reduce the evaporation ratio of the L2NiO solution, affording high-order nucleating points on the substrate. The L2NiO thin films were characterized by X-ray diffraction, scanning electron microscopy, UV–visible spectroscopy, and electrical properties. The figure of merit (FOM) for L2NiO thin films was calculated by Haacke’s formula, and the maximum value was found to be 5.3 × 10−6 Ω−1. FOM results revealed that the L2NiO thin films annealed at 600 °C for 3 h exhibited satisfactory optical and electrical characteristics for photoelectric device applications. Finally, a transparent heterojunction diode was successfully prepared using the L2NiO/indium tin oxide (ITO) structure. The current–voltage characteristics revealed that the transparent heterojunction diode exhibited rectifying properties, with a turn-on voltage of 1.04 V, a leakage current of 1.09 × 10−4 A/cm2 (at 1.1 V), and an ideality factor of n = 0.46.

Treatment of Secondary Dust Produced in Rotary Hearth Furnace through Alkali Leaching and Evaporation–Crystallization Processes

This paper presents the results of an experimental study on the extraction of KCl and the improvement of the zinc grade of secondary dust obtained from rotary-hearth-furnace secondary dust (RHF secondary dust) using alkali leaching (Na2CO3 solution) and evaporation–crystallization processes. The effects of the liquid–solid ratio and Na2CO3 content on the element leaching ratio in the alkali leaching process, as well as the effects of the volume–evaporation ratio and cooling temperature on KCl extraction in the evaporation–crystallization process, were investigated. The results showed that the optimum liquid–solid ratio was 6:1, and the optimum quantity of Na2CO3 was 1.5 times the basic quantity. The recovery ratio of zinc reached 95.23%, and the leaching ratio of K reached 79.01%. The experimental results of the evaporation–crystallization process demonstrated that the evaporation temperature was 80 °C, the volume evaporation ratio was 50%, the cooling temperature was 25 °C, and the mass fraction of K2O in the obtained crystals was 58.99%.

The impact of inlet flash evaporation conditions on erosion damage characteristics of coal gasification black water angle valve and prevention strategies

In view of the three-stage flash evaporation system of the coal gasification plant, a combination of theoretical analysis and numerical simulation was used to establish the erosion damage evaluation model in the black water angle valve. The influence of the inlet flash evaporation ratio on the inlet velocity, the outlet flash evaporation ratio and the outlet velocity of the low-pressure black water angle valve are systematically studied, the mechanism of erosion damage to the carbon steel valve body by the solid medium in black water was analyzed according to the micro-cutting theory. The results show that the inlet velocity w 1, the outlet flash evaporation ratio x 2, the outlet velocity w 2 of angle valve have linear correlation with the inlet flash evaporation ratio x 1.The upstream volume erosion ratio of the angle valve at the inlet flash ratio x 1 = 3 wt.% is 114 times as much as that at zero inlet flash ratio. Meanwhile, the downstream volume erosion ratio of the angle valve at x 1 = 3 wt.% is only 2.7 times as much as that at zero inlet flash ratio. The prevention strategies to reduce the erosion damage to black water angle valve are proposed by inhibiting the inlet flash evaporation ratio and reducing the inlet flow rate etc. This study is expected to provide guidance for the erosion resistance design and operation of the black water angle valve.

Paleoenvironmental changes during the last 3000 years in Lake Cari-Laufquen (Northern Patagonia, Argentina), inferred from ostracod paleoecology, petrophysical, sedimentological and geochemical data

South American paleoreconstructions are of global interest because it is the only landmass extending from the tropics to the southern high latitudes and intersecting the entire southern westerly wind belt. In this context, endorheic environments, as Lake Cari-Laufquen Grande (LCLG; 41º35’S, 69º25’W) are excellent sites for paleoenvironmental studies, since they react rapidly to changes in the precipitation/evaporation ratio. In this study, the limnological conditions prevailing during the last 3000 years have been inferred based on a multiproxy analysis of the sedimentary sequence of LCLG (water depth 4 m, core length 505 cm). Today, this is one of the few lakes in Northern Patagonia, providing a unique paleoclimatic and paleoecological lacustrine record. The ostracod assemblages, along with sedimentological, petrophysical and geochemical data, show hydrological changes in Cari-Lauquen Grande basin during the studied period. Our results indicate the continuous presence of a saline to brackish lake. However, changes in ostracod assemblages and sedimentological features reveal variations in the relative salinity of the system. The lake paleosalinity was estimated based on ostracod salinity optima, using a calibration dataset of 29 species and 72 different environments. Intervals of high salinity (24–26 g L-1) were dominated by L. rionegroensis (morph.I) and organic-poor sediments. Periods of lower salinity (14–20 g L-1) favored the occurrence of oligo-mesohaline taxa, such as R. whatleyi, L. rionegroensis (morph.III), Cypridopsis sp., L. patagonica and I. ramirezi. The sediments further display higher values of both TOC and magnetic susceptibility. These salinity changes are interpreted as water level variations, associated in turn to cold-wet and warm-dry periods in northern Patagonia. Our results provide new insights into the late-Holocene environmental history of the region, characterized by a paucity of records. In addition, the ostracod paleoecology modeled using a WA approach allowed quantitative inferences of salinity changes, highlighting their potential in Quaternary paleoclimate research.