Ratio Of Precipitation Research Articles

EXAMINATION OF CALCITE PRECIPITATION USING PLANT-DERIVED UREASE ENZYME FOR SOIL IMPROVEMENT

The enzyme-mediated calcite precipitation (EMCP) method was established as a soil-improvement technique. This study discussed the possibility of using a plant-derived urease enzyme as a bio-catalyst. The urease enzyme was utilized for the hydrolysis of urea, which causes the supply of calcium ions to precipitate calcium carbonate. Several sources that may contain the urease enzyme were examined. Extracts from cabbage and soy pulp, without purification, were utilized as substitutes for commercial urease enzyme products. Initially, the solution was composed of 15 g/L of crude extract and 1 mol/L each of urea and calcium chloride. The precipitation results using commercial products and crude extracts were compared under the same concentration of reagent solution. A mineralogical analysis of the precipitated materials was also conducted. The mineralogy and morphology of the precipitated materials were examined by Fourier-Transformed Infra-Red (FTIR) spectroscopy, X-Ray Diffraction (XRD), and Scanning Electromagnetic (SEM) tests. The precipitation ratios using the crude extracts as replacements for the urease enzyme were found to be more than 60% of the maximum theoretical value. From the mineralogical and morphological analyses, the calcite mineral was confirmed as the precipitated material. The results of this study indicated that crude extracts from cabbage and soy pulp are potential materials for sources of the urease enzyme

Preparation and performance evaluation of environment-friendly biological dust suppressant

Enzyme-induced carbonate precipitation (EICP) is an economical and eco-friendly technology. The purpose of this study is to evaluate EICP technology for the control of coal dust pollution in open-pit coal mines. A biological dust suppressant was prepared by using urease extracted from soybean. The optimal proportion of biological dust suppressant was determined and the dust consolidation effect of biological dust suppressant was evaluated. The results show that when the volume ratio of urease and CaCl2-urea solution is 1: 3 and the concentration of CaCl2-urea solution is 0.6 mol/L, the precipitation ratio (PR) (83.83%) in coal dust is the highest. Moreover, the mineralization product is calcite-type CaCO3. In the wind erosion-resistance test, when the angle between the air flow and the sample is 0° and the concentration of CaCl2-urea is 0.6 mol/L, the weight loss of coal dust is 2.56%. The corrosive and toxicological properties of biological dust suppressant show that it is non-toxic, less corrosive and weakly alkaline (pH = 7.70). The above results indicate that EICP is a promising coal dust control technology.

Catalytic Mechanism of K and Ca on the Volatile–Biochar Interaction for Rapid Pyrolysis of Biomass: Experimental and Simulation Studies

A good understanding of the catalytic mechanism of alkali and alkaline earth metal species during pyrolysis is required for the development of biomass utilization, to take advantage of its special thermochemical properties. The mechanism of the volatile–biochar interaction, especially between H radical/CO2/H2O and K/Ca in biochar, was systematically investigated by combining experimental analyses and density functional theory calculation. The results indicate that, at 500–900 °C, the yield of biochar from rice husk pyrolysis is basically constant, which mainly shows the mutual conversion between gas and liquid products. With the increase of loading alkali and alkaline earth metal species (AAEMs), the tar yield gradually decreased, and with it reaching a certain content, a significant catalytic effect of AAEMs can be observed. K is more beneficial to maintain the stability of the biochar structure than Ca. The intensities of CO and C–O–C functional groups would appear with a certain increase with the increasing concentration of bond-linking AAEMs. At 700–900 °C, the precipitation ratio of K is almost twice that of Ca and even more. The presence of AAEMs can largely inhibit the formation of three-ring tar components, and more converted to one-ring tar components. The H radicals in the volatile can be bonded to C in the C–O–K structure, thereby causing the K element to decouple with the functional group, and tend to be adsorbed on the carbon matrix. For the Ca-loaded structure, it is manifested in strong adsorption of H radicals by Ca, resulting in the weakening of C–O bonds and the looseness of the biochar structure. The interaction between K/Ca in biochar and H2O/CO2 is reflected in the mutual attraction of AAEMs and the O atom in the H2O/CO2 molecule.

Comprehensive recovery of mixed spent of LiNixCoyMn(1−x−y)O2 and LiFePO4

Lithium-ion batteries are currently being scrapped in large quantities, and there are almost no reports of mixed waste disposal. This paper describes research on a comprehensive recovery process for the mixed waste of LiNixCoyMn(1−x−y)O2 and LiFePO4. The interaction of LiFePO4 and LiNixCoyMn(1−x−y)O2 is utilized to achieve selective leaching through a low H2SO4-low H2O2 system, removal of P and Fe by Fe2(SO4)3-NaOH, preparation of Ni–Co–Mn hydroxide by addition of NaOH, preparation of Li3PO4 using Na3PO4, and separation of Fe and P by acid. The research shows that when 5.23 ml/g 1 M H2SO4 and 0.308 g/g 30% H2O2 were added at 90 °C for 5 h, the leaching ratios of Li, Ni, Mn, and Co achieved were 99.589%, 98.524%, 97.079%, and 96.257%, respectively. At 90 °C and a pH 12 for 2 h, the precipitation ratios of Ni, Co, and Mn were 99.79%, 99.89%, and 99.89%, respectively. A total of 55.12 g/l of Na3PO4 was added to the solution to effect settling of Li, and a sedimentation rate of 98.46% was achieved. The leaching residue was dissolved in 3 M HCl of 6.62 ml/g, and the achieved leaching ratio of the FePO4 was more than 95%.

Future changes in Aridity Index at two and four degrees of global warming above preindustrial levels

AbstractIn this study, we project the global terrestrial changes in Aridity Index (AI), as defined by the ratio of annual precipitation to potential evapotranspiration (PET), at 2 and 4°C levels of global warming above the preindustrial conditions based on the outputs from 21 Coupled Model Intercomparison Project Phase 5 models under the Representative Concentration Pathways 8.5 (RCP8.5) scenario. Compared to the preindustrial period, the global terrestrial annual precipitation will increase by an average of 0.02% (3%), the annual PET will increase by 6% (15%) and AI will decrease by 0.1 (0.2) at the 2°C (4°C) warming level. More remarkable decreases in the annual AI are seen in the northern high latitudes, where will also experience greater increases in PET and precipitation. In general, the seasonal changes in AI display a similar spatial pattern to the annual changes and are characterized by the greatest decrease in December–January–February and the smallest in June–July–August. The largest expansion of drylands occurs in semi‐arid regions, followed by the expansion of arid regions, with area changes of 4% (7%) and 3% (4%) under the 2°C (4°C) scenario, respectively. Further analyses indicate that the AI changes are determined by PET in the northern high latitudes, and the contribution of PET to AI increases from the 2 to 4°C warming levels. Furthermore, changes in thermodynamic factors contribute most to the PET, and at a higher level of global warming, the contribution of thermodynamic factors increases and that of dynamic factors decreases.

SAT-426 Macro-Thyroid Stimulating Hormone (TSH) in Children

Macro-TSH is mainly a complex of TSH with anti-TSH autoantibodies. Due to its large molecular size (>150 kDa), it accumulates in the circulation resulting in elevated serum TSH concentrations. Because the bioactivity of macro-TSH is low, treatment with thyroxine is not necessary. The prevalence of macro-TSH is no more than 1% in adult patients with subclinical hypothyroidism. However, the prevalence of macro-TSH in children is not known. We report here two cases of macro-TSH in pediatric setting.[Case reports] Case 1. Six-year and eight-month-Japanese boy visited a pediatric hospital because of hyperactivity disorder. Physical examination revealed that he had a slight mental retardation (IQ 63 by Tanaka-Binet test). Thyroid tests showed that fT4 1.21 ng/dL, TSH 120.4 µU/mL, Tg antibody 1.9 IU/mL, TPO antibody <0.1 IU/mL. His serum was sent to our laboratory to examine the causes of inappropriate high serum TSH concentration. Case 2. Eight-year and three-month-Turkish girl was brought to a pediatric hospital by her parents because of her yellowish palms, which was not identified at the hospital. She did not have any complaints and physical signs attributable to thyroid dysfunction. Laboratory data disclosed that fT4 1.5 ng/dL, TSH 19.6 µU/mL, Tg Ab negative, TPO Ab negative. Levothyroxine treatment started but serum TSH concentration was still high (39.0 µU/mL) after two months. Her serum sample was sent to our laboratory to examine the causes of inappropriate high serum TSH concentrations.[Lab. Tests for macro-TSH]When serum was mixed with the same amount of 25% polyethylene glycol (PEG) and γ-globulin fraction was precipitated, TSH concentration in the supernatant decreased significantly from 109.3 µU/mL to 2.3 µU/mL (PEG precipitation ratio 97.9%) in case 1, and from 17.3 µU/mL to 0.15 µU/mL (PEG precipitation ratio 99.1%) in case 2. HAMA blockers did not significantly change TSH concentration in both cases. High proportion of serum TSH bound to a protein G column, which binds IgG, in case 1 (91.3%) and in case 2 (57.7%), indicating that TSH was associated with IgG. Gel filtration chromatography (GFC) revealed that TSH was mostly eluted at the fraction > 150 kDa rather than 28 kDa of authentic TSH in both cases. Serum was incubated with 37.7 µU of TSH for one hour and subjected to GFC. TSH concentration in the fraction of 150 kDa (macro-TSH) increased from 2.8 µU/mL to 5.6 µU/mL in case 1 and from 0.4 µU/mL to 2.0 µU/mL in case 2, suggesting that macro-TSH was produced by the binding of exogenous TSH to anti-TSH autoantibodies.[Conclusion]Macro-TSH exists in children and careful evaluation is required in patients with inappropriate high serum TSH concentrations to avoid unnecessary treatment.

Potential dry/wet dynamic in China under RCP scenarios

Dry and wet division is one of the most basic contents in climate classifications. In order to explore regional potential features, 20 global climate models (GCMs) were statistically downscaled to reproduce temperature and precipitation at a resolution of 0.25° × 0.25° across China, which illustrated agreeable performance in comparison with observation. Taking temperatures as inputs, the Hargreaves model was implemented to estimate potential evapotranspiration (PET). This model was typically recalibrated to keep accuracy in further usage, which resulted in normalized root mean squared error being less than 5%. The indicator defined by the ratio of annual precipitation to annual PET, namely dry/wet index (IDW), was projected in potential dynamic of dry/wet division. IDW was consistently expected in an increasing trend under RCP4.5 relative to the baseline period of 1986–2005. Regards RCP8.5, IDW was diagnosed in a decreasing trend in northern Xinjiang and most central-southern regions, but an increasing trend in most northern regions, implying dry tendency in current wet condition in southern parts while wet tendency in dry condition in northern parts. The possible contribution of precipitation and PET could unveil regional differential change in IDW. It was highlighted that the area exposed to extreme dry, and dry was likely to decrease, but the exposure to wet and extreme wet tended to increase in the future. These can provide a better knowledge of potential change of climate and water resource, supporting adaptive strategies in response to climate change.

Vertical Temperature Structure Associated with Evaporation of Stratiform Precipitation in Idealized WRF Simulations

AbstractA recent study based on observations has shown that after precipitation over tropical oceans rather shallow temperature structures occur in the lower troposphere and that their magnitude depends on climatological low- to midtropospheric humidity. As any process that produces temperature perturbations in the lower troposphere can be of great significance for the formation of atmospheric deep convection, the vertical temperature structure associated with evaporation of stratiform precipitation and its sensitivity to low- to midtropospheric humidity are studied by conducting three-dimensional, high-resolution, idealized simulations with the Advanced Research version of the Weather Research and Forecasting (WRF) Model. In the simulations, rainwater with mixing ratio and number concentration characteristic of stratiform precipitation associated with mesoscale convective systems is added in a large round area at roughly 560 hPa. Evaporative cooling and subsidence warming below result in a cold anomaly at roughly 560–750 hPa and, especially, a warm anomaly at roughly 750–900 hPa. The cold-over-warm anomalies are stronger with smaller low- to midtropospheric relative humidity in the initial conditions, with the maximum magnitude of the warm anomaly ranging between 0.7 and 1.2 K. The temperature anomalies propagate to the environment and still remain present after precipitation stops. The results show that evaporation of stratiform precipitation alone can lead to temperature structures, which are on the same order of magnitude as the observed ones, that potentially inhibit subsequent convection by increasing convective inhibition. Therefore, the representation of microphysical processes affecting the location, amount, and vertical and horizontal distribution of stratiform precipitation and its evaporation in numerical models requires special attention.

Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations

Based on the concept of recycling waste with waste, the mixed cathode materials of spent lithium-ion batteries were recycled with waste electrolyte from spent lead–acid batteries. With the assistance of thermodynamic simulations, the optimized recycling path of the mixed cathode materials was proposed and tested. A higher overall recycling ratio of valuable metals, that is, 94.9% of lithium, 94.5% of cobalt, 94.4% of nickel, and 95.5% of manganese, was achieved by replacing the oxalates/carbonates used in the precipitation process with sulfides and reducing the solubility of lithium carbonate in the lithium precipitation step at room temperature with ethanol. A higher ethanol-to-water ratio yielded a higher precipitation ratio of lithium until the ratio reached 5:1. High-purity lithium carbonate and cobalt (99.9%) were recovered as nanoparticles and nanoribbons, respectively, through precipitation using carbon dioxide in a solution with a 4:1 ethanol-to-water ratio and electrodeposition at E = −0.4 V in a traditional three-electrode system. Furthermore, the poisonous heavy metal (lead) was separated and stabilized as lead sulfide.

Impacts of Assimilating ATMS Radiances on Heavy Rainfall Forecast in RMAPS-ST

The Advanced Technology Microwave Sounder (ATMS) mounted on the Suomi National Polar-Orbiting Partnership (NPP) satellite can provide both temperature and humidity information for a weather prediction model. Based on the rapid-refresh multi-scale analysis and prediction system—short-term (RMAPS-ST), we investigated the impact of ATMS radiance data assimilation on strong rainfall forecasts. Two groups of experiments were conducted to forecast heavy precipitation over North China between 18 July and 20 July 2016. The initial conditions and forecast results from the two groups of experiments have been compared and evaluated against observations. In comparison with the first group of experiments that only assimilated conventional observations, some added value can be obtained for the initial conditions of temperature, humidity, and wind fields after assimilating ATMS radiance observations in the system. For the forecast results with the assimilation of ATMS radiances, the score skills of quantitative forecast rainfall have been improved when verified against the observed rainfall. The Heidke skill score (HSS) skills of 6-h accumulated precipitation in the 24-h forecasts were overall increased, more prominently so for the heavy rainfall above 25 mm in the 0–6 h of forecasts. Assimilating ATMS radiance data reduced the false alarm ratio of quantitative precipitation forecasting in the 0–12 h of the forecast range and thus improved the threat scores for the heavy rainfall storm. Furthermore, the assimilation of ATMS radiances improved the spatial distribution of hourly rainfall forecast with observations compared with that of the first group of experiments, and the mean absolute error was reduced in the 10-h lead time of forecasts. The inclusion of ATMS radiances provided more information for the vertical structure of features in the temperature and moisture profiles, which had an indirect positive impact on the forecasts of the heavy rainfall in the RMAPS-ST system. However, the deviation in the location of the heavy rainfall center requires future work.

Subannual Streamflow Responses to Rainfall and Snowmelt Inputs in Snow‐Dominated Watersheds of the Western United States

AbstractStreamflow generation in mountain watersheds is strongly influenced by snow accumulation and melt, and multiple studies have found that snow loss leads to earlier snowmelt timing and declines in annual streamflow. However, hydrologic responses to snow loss are heterogeneous, and not all areas experience streamflow declines. This research examines whether streamflow generation is different for rainfall versus snowmelt inputs. We compiled a sample of 57 small U.S. Geological Survey watersheds in the western United States containing a Natural Resource Conservation Service Snow Telemetry site and having ratios of mean annual peak snow water equivalent to precipitation ratios &gt;0.25. Daily streamflow was separated into quickflow and baseflow using a digital filter, and quickflow was then divided into quickflow response intervals using thresholds in quickflow slope. Each quickflow response interval was categorized by its fraction of input from snowmelt. Most sites exhibited two streamflow generation peaks each year, with one peak in the winter when runoff efficiency is greatest, and the second in the spring during peak snowmelt input. On average, study watersheds were dominated by snowmelt inputs (70%), and snowmelt and mixed inputs usually generated greater streamflow than rainfall because of higher inputs and longer durations. However, rainfall produced high streamflow generation in winter, when watersheds have their highest runoff efficiency (81%) across all input types. We demonstrate that while snowmelt is important for streamflow generation due to high input over long periods, increases in rain and mixed input during wet winter periods can countervail tendencies for reduced streamflow with declining snowpacks.

VARIABILITY OF COMPONENT COMPOSITION OF MELISSA OFFICINALIS L. ESSENTIAL OIL DEPENDING ON THE CLIMATIC CONDITIONS OF THE REGION OF CULTIVATION

The aim of the research was to detect the dependence of content and component composition of Melissa officinalis L. essential oil from climatic peculiarities of the region of cultivation and to specify the optimum conditions for growing high-quality raw materials. We presented the results of the comparative assessment of essential oil component composition (three main elements) obtained from air-dried raw materials of two cultivars Krymchanka and Lada. These Melissa officinalis L. cultivars were grown in three regions that sharply differed in weather conditions. To make the comparison accurate, we determined the component composition of essential oil in the Laboratory of Biochemistry at FSBSI “Research Institute of Agriculture of Crimea” using gas chromatograph Kristall 5000.2. The most favorable climatic conditions for essential oil accumulation were in the Foothill zone of the Crimea (moderate rainfalls combined with high air temperatures). Cultivar Krymchanka exceeded cultivar Lada by the amount of essential oil in raw materials. Excess sometimes reached 170%. Dependence of the main components such as citral, β-caryophyllene, caryophyllene oxide, germacrene D from the ratio of temperature and precipitation was revealed. After obtaining research results, we could suggest that by controlling the conditions of cultivation of M. officinalis, it is possible to adjust the ratio of the components of essential oil.

Arid/humid patterns over Asia in response to national-committed emission reductions under the Paris agreement

The evolution of regional arid/humid patterns caused by global climate change deserves attention. We investigated the changes in the area of arid/humid climate regions over Asia under the aegis of national-committed emission reductions to comply with the Paris Agreement using an ensemble of 17 global climate models (GCMs) from the Fifth Coupled Climate Model Intercomparison Project (CMIP5) archives. Our results indicated an overall trend towards aridity in a future warmer climate based on an aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET). In the future, the humid region will contract and the arid region and arid/humid transition zones will expand. Compared with the present period, arid/humid region switch is projected to occur in a land area of 2512.8 × 103 km2 over Asia under the Intended Nationally Determined Contributions (INDC)-pledge scenario. If global warming is controlled to the ambitious 2.0 °C and 1.5 °C scenarios instead of that of the INDC-pledge scenario, a decrease in the changes in the area of arid/humid regions by more than half would be expected. In addition, the arid/humid regions with continuous global warming are estimated to contract/expand greatly. Changes in the spatial pattern of the arid/humid zones over Asia show strong similarities between multi-model simulations, although there are some differences in detail.

Seed productivity and variability of Scots pine (Pinus sylvestris L.) clones of Finnish origin in seed orchard in the central part of Ukraine

Abstract Global climate change has mainly impacted the forest ecosystems in Europe. Today, it is not fully understood how these changes will affect the reproductive process of trees on seed orchards. The main aim of the study is to evaluate the growth, condition and reproductive function of Scots pine clones of Finnish origin after moving them to the southern direction of natural distribution area. Variability and seed productivity of 25-year-old clones of Scots pine of Finnish origin in the clonal seed orchard under climatic conditions of the central part of Ukraine (Vinnitsa region) was investigated. Grafted seedlings of Scots pine of Finnish origin were moved southward at a distance of over 1,500 km. Climatic conditions of Vinnytsia region, where the clones were displaced, differed by an increase in the mean and maximum temperatures by 3.3–3.6ºC, as well as an increase in the mean temperatures during the cold period and a rise in the minimum by 2.1–2.3ºC. The climate in the seed orchard location was characterized by the most significant increase in the mean temperatures in April and May (5.3–5.8ºC), which greatly influenced the intensity of the formation of microstrobili and macrostrobili. The ratio of precipitation to the amount of temperatures decreased more than twice. Analysis of the grafted trees’ vitality of Finnish origin and seed progeny of the local population, estimation of their intensity (height, diameter), state (category of the state) and reproductive processes (intensity of formation of microstrobili and cones) was carried out on the clonal seed orchard. In conditions of climate change, most of the clones of Finnish origin were characterized by a higher intensity of flowering compared to the local population. Some clones of Finnish origin (E80 and E729) dominated the local population by the seed yield. According to a comprehensive analysis of vitality, the intensity of growth and reproductive capacity, the best clones of Finnish origin were E80, E1883 and E2254. Low adaptive ability was noted in the clones E2312, K634 and K801. According to the research results, it was found that changes in climatic conditions did not significantly affect the vitality, development and condition of the clones. There was observed intensification of the formation of microstrobili and cones. Seed viability and quality of Scots pine of Finnish origin obtained on seed orchards located in the southern conditions requires further research.

The stable isotopic composition variation characteristics of desert plants and water sources in an artificial revegetation ecosystem in Northwest China

Characterizing the dynamics of plant water availability and the mechanisms through which plants access available water sources are key challenges in ecohydrology, especially in arid and semi-arid regions. The establishment of artificial revegetation of different ages has formed vegetation landscapes with different chronological sequences in the southeast margin of the Tengger Desert. As an important regulatory factor of the Soil Plant Atmosphere Continuum (SPAC) system, changes in vegetation characteristics will affect the water uptake of the entire ecosystem. In this study, the δ2H and δ18O isotope ratios in precipitation, plant water, soil moisture, and underground water, and the δ13C isotope ratio of plant leaves were measured using the stable isotope technique for artificial revegetation used to fix the sand dunes in the Tengger Desert. The purpose of this study was to establish the isotope content and characteristics of potential water sources for plants and leaf carbon isotopes, to clarify whether the soil moisture condition and duration of sand-fixing influenced the isotopic signal, and to identify the main water source for desert plants. The results indicated that air temperature and amounts of precipitation were two important influencing factors in precipitation isotope ratio change. Soil water isotopic ratios were different under different water conditions, and under the same water conditions, the vertical variation in soil water isotopes in a single area and spatial variation at any depth for different revegetation areas were all significant (p < 0.01). Shallow soil waters were enriched in isotope ratios and the value increased with an increase of the sand-fixing duration (as found in older revegetation areas). The δ2H and δ18O values in Caragana korshinskii leaves were higher than they were in Artemisia ordosica leaves because the former has a higher transpiration rate. The higher δ13C value of Artemisia ordosica plant leaves indicated high water use efficiency, which is a result of better adapting to the arid environment compared to Caragana korshinskii. Overall, water uptake of these two shrubs was mainly (>70%) concentrated at a soil depth of 20–150 cm. For Caragana korshinskii plants, the 60–150 cm soil layer was the main water supply layer, while the water contribution layer of Artemisia ordosica plants focused on the 20–100 cm soil layer and the contribution rate of shallow soil water increased with the increase of sand fixation time in older revegetation areas, regardless of the species used for revegetation.

Effect of Aerosol Particles on Orographic Clouds: Sensitivity to Autoconversion Schemes

Aerosol particles can serve as cloud condensation nuclei (CCN) to influence orographic clouds. Autoconversion, which describes the initial formation of raindrops from the collision of cloud droplets, is an important process for aerosol-cloud-precipitation systems. In this study, seven autoconversion schemes are used to investigate the impact of CCN on orographic warm-phase clouds. As the initial cloud droplet concentration is increased from 100 cm−3 to 1000 cm−3 (to represent an increase in CCN), the cloud water increases and then the rainwater is suppressed due to a decrease in the autoconversion rate, leading to a spatial shift in surface precipitation. Intercomparison of the results from the autoconversion schemes show that the sensitivity of cloud water, rainwater, and surface precipitation to a change in the concentration of CCN is different from scheme to scheme. In particular, the decrease in orographic precipitation due to increasing CCN is found to range from −87% to −10% depending on the autoconversion scheme. Moreover, the surface precipitation distribution also changes significantly by scheme or CCN concentration, and the increase in the spillover (ratio of precipitation on the leeward side to total precipitation) induced by increased CCN ranges from 10% to 55% under different autoconversion schemes. The simulations suggest that autoconversion parameterization schemes should not be ignored in the interaction of aerosol and orographic cloud.

The effects of pH on copper leaching from wood treated with copper amine-based preservatives

Abstract As pH of leaching medium is an important factor in the leaching of wood preservative components, its effects on leaching should be quantified to ensure environmentally safe use of treated wood. In this study, the effects of pH on leaching of copper from wood treated with copper amine-based preservatives [alkaline copper quat (ACQ)-2, bis-(N-cyclohexyldiazeniumdioxy)-copper (CuHDO)-3, and copper azole (CUAZ)-3] were evaluated in comparison with wood treated with chromated copper arsenate (CCA)-3. Radiata pine sapwood blocks treated with these preservatives were leached at five pH levels (3.0, 3.5, 4.0, 4.5, and 6.5). The leached blocks were subjected to laboratory-scale decay tests using two brown-rot fungi. The blocks treated with copper amine-based preservatives leached significant amounts of copper at pH levels below 4.0. At all pH levels, the CuHDO-3-treated samples generally leached the most copper, followed by the samples treated with ACQ-2, CUAZ-3, and CCA-3. When the treated blocks were leached at pH 3.0, the degradation of hemicelluloses, which can chemically adsorb copper, was confirmed through Fourier transform infrared attenuated total reflectance (FTIR-ATR) analysis. Moreover, X-ray photoelectron spectroscopy (XPS) analysis indicated that the ratio of precipitates of the remaining copper in the treated wood severely decreased after leaching at pH levels below 4.0. Subsequent reduction in the biological effectiveness of wood treated with copper amine-based preservatives was not hardly observed after leaching at pH levels 4.0 or above. These results indicate that copper loss at pH levels 4.0 or above is not great enough to cause public concern about environmental problems and reduction of biological efficacy in practical applications.

Study of precipitation and growth processes of Ti-bearing inclusions in tire cord steel

Precipitation behavior and growth kinetics of Ti-bearing inclusions in SWRH 92A tire cord steel were analyzed in the present work. The calculated results showed that higher cooling rate would lead to a higher precipitation ratio of solution elements and make the precipitation time of inclusions earlier. However, both TiCyN1−y (a continuous solid solution between TiC and TiN, y denotes the molar ratio of TiC in TiCyN1−y) and TiN could only precipitate in the two-phase region at the very late stage during the solidification processes, with the solid fraction exceeds 0.99. The precipitation time of TiCyN1−y was a little earlier than that of TiN as well as the value of y in the range of 0.1577–0.1617 (cooling rate: 0.5–2 K/s) was also obtained. Particle size of Ti-bearing inclusions decreased with the increasing cooling rate and were within the range of 1.5–6.5 μm under the calculated conditions, which accorded well with the size observed by the FE-SEM (field emission scanning electronic microscope). Increasing the contents of both N and Ti could lead to an earlier precipitation time of Ti-bearing inclusions and make the particle size bigger, while the effect of N is much larger than that of Ti. The results obtained by the adopted model were in well consistent with those of the statistical analysis. This work may give an important guidance on the understanding of the precipitation and growth processes of Ti-bearing inclusions in tire cord steel.

Enriching lithium and separating lithium to magnesium from sulfate type salt lake brine

Extraction of lithium from salt lake brine has become a research highlights due to the rapid development of lithium ion battery. There are abundant lithium resources in sulfate type salt lake in China. In this work, the process of enriching lithium and separating lithium to magnesium from simulated sulfate type brine was carried out based on the reaction of Al/Na2SO4 composite with brine. The results show that Al/Na2SO4 composite can be used to enrich lithium from Li2SO4 solution in the form of Li2Al4(OH)12SO4·xH2O and the lithium precipitation efficiency reaches 89.2% under the optimal conditions. The existence of magnesium in solution is adverse to the precipitation process of lithium. The coating of compact MgAl hydrotalcite on the surface of aluminum based material hinders the reaction of Al/Na2SO4 composite with brine and the lithium precipitation efficiency decreases to 54.7% when the Mg/Li mass ratio in solution is 20:1. However, the Mg/Li mass ratio in precipitate is less than 0.3 under the optimal conditions. The results are beneficial for the enriching lithium and separating lithium to magnesium from sulfate type brine.

Spatiotemporal variations of aridity index over the Belt and Road region under the 1.5°C and 2.0°C warming scenarios

Aridity index reflects the exchanges of energy and water between the land surface and the atmosphere, and its variation can be used to forecast drought and flood patterns, which makes it of great significance for agricultural production. The ratio of potential evapotranspiration and precipitation is applied to analyse the spatial and temporal distributions of the aridity index in the Belt and Road region under the 1.5°C and 2.0°C global warming scenarios on the basis of outputs from four downscaled global climate models. The results show that: (1) Under the 1.5°C warming scenario, the area-averaged aridity index will be similar to that in 1986–2005 (around 1.58), but the changes vary spatially. The aridity index will increase by more than 5% in Central-Eastern Europe, north of West Asia, the monsoon region of East Asia and northwest of Southeast Asia, while it is projected to decrease obviously in the southeast of West Asia. Regarding the seasonal scale, spring and winter will be more arid in South Asia, and the monsoon region of East Asia will be slightly drier in summer compared with the reference period. While, West Asia will be wetter in all seasons, except winter. (2) Relative to 1986–2005, both areal averaged annual potential evapotranspiration and precipitation are projected to increase, and the spatial variation of aridity index will become more obvious as well at the 2.0°C warming level. Although the aridity index over the entire region will be maintained at approximately 1.57 as that in 1.5°C, the index in Central- Eastern Europe, north of West Asia and Central Asia will grow rapidly at a rate of more than 20%, while that in West Siberia, northwest of China, the southern part of South Asia and West Asia will show a declining trend. At the seasonal scale, the increase of the aridity index in Central-Eastern Europe, Central Asia, West Asia, South Asia and the northern part of Siberia in winter will be obvious, and the monsoon region in East Asia will be drier in both summer and autumn. (3) Under the scenario of an additional 0.5°C increase in global temperature from 1.5°C to 2.0°C, the aridity index will increase significantly in Central Asia and north of West Asia but decrease in Southeast Asia and Central Siberia. Seasonally, the aridity index in the Belt and Road region will slightly increase in all other seasons except spring. Central Asia will become drier annually at a rate of more than 20%. The aridity index in South Asia will increase in spring and winter, and that in East Asia will increase in autumn and winter. (4) To changes of the aridity index, the attribution of precipitation and potential evapotranspiration will vary regionally. Precipitation will be the major influencing factor over southern West Asia, southern South Asia, Central-Eastern Siberia, the non-monsoon region of East Asia and the border between West Asia and Central Asia, while potential evapotranspiration will exert greater effects over Central-Eastern Europe, West Siberia, Central Asia and the monsoon region of East Asia.