Narrow Results

The hydrological cycle in the natural environment plays a crucial role in influencing human societal progress and everyday life, particularly in the realm of agriculture. Precipitation is a vital component of the natural water cycle. In recent years, multiple approaches for estimating rainfall have been developed by researchers to achieve improved results. However, the precision of conventional rainfall estimation techniques remains inconsistent, particularly in instances of heavy rainfall, which can result in considerable errors. Scholars have turned their attention to deep learning techniques, which excel at processing raw data and autonomously identifying model parameters. In this study, we present and compare two deep learning frameworks for precipitation estimation based on BPNN and CNN, in contrast to traditional methods. We also use a real dataset to validate the effectiveness of the deep learning models, and the experimental outcomes indicate that the CNN-based precipitation estimation method outperforms several other models.

The current study aims to estimate the influence of enhanced nitrogen on the hot ductility of medium carbon microalloyed steel. For this purpose, hot tensile tests were carried out at temperatures rangeing from 700°C-1000°C at a true strain rate of 0.001s^-1. The fracture surfaces and their neighboring precipitates and matrix microstructures "frozen" in tensile temperatures were observed. The dependence of hot ductility on the fracture mode and in situ microstructural changes were discussed. The results indicate that raising the nitrogen content from 0.003% to 0.014% and 0.021% was found to deteriorate the ductility as the obtained ductility trough became deeper and wider. The trough deepening caused by the addition of nitrogen was due to the formation of film-like ferrite and fine VN precipitation along the austenite grain boundaries promoting low ductility intergranular failure. On the other hand, the retarded dynamic recrystallization, the promoted deformation induced ferrite formation and precipitation at higher temperatures by enhanced nitrogen were regarded as the possible reasons for a wider trough. In summary, the above results indicate the hot ductility of medium carbon microalloyed steels is weakened to some extent by enhanced nitrogen and their windows suitable for continuous casting should be schemed very carefully.

Our aim is to contribute to comprehension of the phenomena of precipitation in the Al–Zn–Mg alloys. For this, we have made a comparative study of the transformations of phases using the differential scanning calorimetric and the dilatometry. This last technique is relatively new in the case of Al–Zn–Mg alloys. It consists of two opposite effects (contraction and expansion) observed on the dilatometric curves. These effects translate two opposite metallurgical phenomena which are generally the precipitation and the dissolution.

The precipitation phenomena and the related hardening in an Al–Cu–Mg–Si alloy were studied by calorimetry, X-ray diffraction analysis and microhardness measurements. The main calorimetric peaks were identified to be due to β^′′, θ′ and Q′ phases precipitation. The hardening during aging at room temperature and 160°C, was respectively, explained by atomic clusters and GP zones formation and by GP zones and β^′′/θ′ phases coprecipitation. Although the mechanical properties variation during aging at 200°C is simple, the corresponding microstructural evolution is complex: on the basis of the DSC results, the increasing of microhardness values, is mainly due to the coprecipitation of GP zones and β^′′/θ′ phases, however, the maximum hardening is explained by the coexistence of β^′′/θ′ and θ^′′ phases. Another important conclusion is that during aging at 160°C and 200°C, the θ′ phase is essentially developed from GP zones.

Nanostructured strontium tungstate was successfully synthesized by a co-precipitation method at 80°C. The structure and morphology of the obtained SrWO₄ were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD pattern conformed that the prepared sample has a scheelite-type tetragonal structure. The electrochemical properties of the SrWO₄ were investigated in 0.5 M NaOH electrolyte solution by cyclic voltammetry (CV), galvanostatic charge–discharge cycling and electrochemical impedance spectroscopy (EIS) measurements. Also, platinum have been supported onto the surface of SrWO₄/graphite electrode to use as catalyst support. The morphology of the catalysts was characterized by scanning electron microscopy analysis and EDX. The electrocatalytic activity of platinum loaded SrWO₄/graphite electrode toward oxygen reduction reaction (ORR) has been studied in 0.5 M H₂SO₄ solution and compared with that of platinum supported on graphite using electrochemical measurements. The PtSrWO₄/graphite catalyst showed higher ORR activity than Pt/graphite catalyst.

In this study, the synthesis of a cerium oxide nanoparticle was carried out from Acalypha indica leaf extract. The synthesized nanoparticle was characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) and Transmission Electron Microscope (TEM) for structural confirmation. The studies clearly indicate that the synthesized CeO₂ nanoparticle is a crystalline material with particle size between 25–30 nm. Further analysis was carried out by Fourier Transform infrared spectroscopy (FT-IR), to provide evidence for the presence of Ce-O-Ce asymmetry stretching of the CeO₂ nanoparticle. Thermo Gravimetric and Differential Scanning Calorimetry analyses gave the thermal properties of cerium oxide nanoparticles. Antibacterial studies were conducted using the synthesized CeO₂. This result showed increasing rate of antibacterial behavior with gram positive and gram negative bacteria.

Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of cerium dioxide (CeO₂) nanoparticles in alcohol/water mixed solvents by homogeneous precipitation method. The results showed that properly selecting the sizes of CeO₂ and water beads, and choosing the appropriate interaction parameters between beads are crucial in the simulation system. The nucleation and crystal growth process of CeO₂ can be classified into four stages: induction, nuclei growth, crystal forming, and crystal aggregation, which could be reproduced from different initial CeO₂ concentration and after different simulation time. The simulation results confirm that the effect of solvent on the nucleation and crystal growth of CeO₂ nanoparticles are different at four stages and cannot be simply described by Derjaguin–Landau–Verwey–Overbeek theory or nucleation thermodynamics theory as proposed in the published literatures. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

Zinc oxide (ZnO) and yttrium-doped ZnO nanoparticles with particle size in the nanometer range have been successfully synthesized by the alkali precipitation method. The nanoparticle size and morphology have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The average particle size of Y-doped ZnO nanoparticles is about 17–29 nm. The absorption and photoluminescence (PL) spectra of the undoped and doped ZnO nanoparticles were also investigated. The optical band gap of ZnO nanoparticles can be tuned from 3.27 to 3.40 eV with increasing yittrium doping levels from 0 to 5%. The nanoparticles gave two emission peaks, one at around 376 nm and the other at 500 nm.

In this study, WO₃–rGO nanocomposites were synthesized via a facile chemical method followed by a calcination process. The samples were characterized by UV-Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, BET technique, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results confirmed the formation of the nanocomposites. Photocatalytic activity of the synthesized samples was evaluated in degradation of 1-naphthol as a polycyclic aromatic pollutant under irradiation of xenon lamp. The concentration of the pollutant was measured by high performance liquid chromatography (HPLC). Efficient photocatalytic performance was observed and the kinetics data were well described by Langmuir–Hinshelwood model.

The cyclic deformation behavior of [001] oriented Fe-28Ni-17Co-11.5Al-2.5Ta (at.%) shape memory single crystals was investigated under tension. Dog-bone shaped specimens were tested up to 100 cycles after different aging heat treatments in order to characterize the cyclic stress–strain response and functional degradation. The smaller particles formed as a consequence of short aging for 1 h at 700°C, as compared to longer aging for 7 h, resulted in significantly enhanced resistance to cyclic degradation.

The main effects of $\gamma$ non-equilibrium nanoprecipitates in CuZnAl shape memory alloys are briefly reviewed. Aspects related to the nucleation and growth of precipitates are commented on and their effect on stress induced martensitic transitions is analyzed. Results concerning the relationship between the size of precipitates and the hysteresis of the stress induced $\beta$-18R transition are studied. The improvement of the two-way shape-memory effect after the introduction of precipitates is shortly commented on. The 18R–6R transition is also analyzed and recent findings on the optimization of the mechanical reversibility associated to the 18R–6R transformation in a matrix with a high density of nano precipitates are reviewed.

Fe-Ni-Co-Al-Ta polycrystalline shape memory alloys have received extensive attention due to their excellent properties such as huge superelasticity, high strength and high damping. We herein report that Fe-Ni-Al-Ta polycrystalline alloys also have excellent superelasticity, which can exhibit a large superelastic strain of more than 17% in compression at room temperature. This superelasticity has slim hysteresis and is greatly affected by the content of Ta in the alloys. In this work, Fe-Ni-Al-Ta shape memory alloys reveal some characteristics that are different from the reported Fe-Ni-Co-Al-based shape memory alloys.

There is a paucity of information on conditioning factors that hinder or promote adoption of multiple climate-smart practices and on the synergies among such practices in increasing household resilience by improving agricultural income. This study analyzes how heat, rainfall, and rainfall variability affect farmers’ choices of a portfolio of potential climate smart practices — agricultural water management, improved crop seeds, and fertilizer — and the impact of these practices on farm income in the Nile Basin of Ethiopia. We apply a multinomial endogenous switching regression approach by modeling combinations of practices and net farm income for each combination as depending on household and farm characteristics and on a set of climatic variables based on geo-referenced historical precipitation and temperature data. A primary result of this study is that farmers are less likely to adopt fertilizer (either alone or in combination with improved varieties) in areas of greater rainfall variability. However, even when there is high variability in rainfall, farmers are more likely to adopt these two yield-increasing inputs when they choose to (and are able to) include the third part of the portfolio: agricultural water management. Net farm income responds positively to agricultural water management, improved crop variety or fertilizer when they are adopted in isolation as well as in combination. But this effect is greater when these practices are combined. Simulation results suggest that a warming temperature and decreased precipitation in future decades will make it less likely that farmers will adopt practices in isolation but more likely that they will adopt a combination of practices. Hence, a package approach rather than a piecemeal approach is needed to maximize the synergies implicit in various climate smart practices.

Through studying vegetation phenology and its relation to meteorological factors in a representative region, we can get the responsiveness of vegetation phenophase in different sites to climate changes and how it affects vegetation productivity by the changes of growing season. It is crucial to enhance the accuracy of carbon sequestration estimate. We use phenological observation data and corresponding meteorological data from weather stations of six counties in Qinghai province. The conclusions are (1) In the background of global climate change, the temperature of the pastoral area of Qinghai takes a significantly increasing trend. The precipitation also takes an increasing trend, but only the site of Qumalai is significant. (2) The green-up dates of forages in every site are not significant, but the withered dates of forages are significantly put off. In the sites of Gande and Haiyan, the major forages put off in withered dates are Gramineae, in the site of Henan, Cyperaceae is significantly put off. Significantly extended growing season of representative forages of Gramineae, Cyperaceae and other broad-leaved herb exist in the pastoral area of Qinghai. (3) In terms of relations between green-up date and temperature, the influence of site scale is greater than the influence of different species, and advanced green-up dates of forages in the sites of Henan and Haiyan are longer than the dates of the same forages in the site of Gande. Overall, green-up dates of forages advanced in the site of Henan (Avg3.67 days/$+1^{\circ }$C) are longer than the dates in the site of Gande (Avg1.31 days/$+1^{\circ }$C). In terms of relations between green-up date and precipitation, divergences of sites and species exist. The green-up dates of forages in the sites of both Qumalai and Tongde have significant negative correlation with precipitation. In the site of Haiyan, the green-up dates of some forages advance, and the green-up dates of some forages put off. On the whole, Gramineae is best responded, then Cyperaceae and broad-leaved herb show hardly any responsiveness. (4) The responsiveness of temperature is less than precipitation in the pastoral area of Qinghai. Forages in Tongde and Qumalai have significantly positive correlation with the accumulation precipitation from August to September. The differences are the delayed dates of the withered dates of Cyperaceae (2.97 days/10mm) which are longer than the delayed dates of the withered dates of Gramineae (2.02 days/10mm) in the site of Qumalai. Conversely, the delayed dates of the withered dates of Gramineae (3.13 days/10mm) are longer than the delayed dates of the withered dates of Cyperaceae (1.68 days/10mm) in the site of Tongde. (5) Only parts of sites in the pastoral area of Qinghai have the tendency of significant increment of forage yield. The precipitations in the sites of Gande, Qumalai and Xinghai can significantly increase the forage yield. (6) The main vegetation phenology and productivity changes are affected by the drivers of climate factors. The response patterns of vegetation phenology of different functional groups and forage yield of different regions are inconsistent with the climate factors which are related to the biologic characteristics of different kinds of vegetations and climate sensitivities.

In this study, we assess the future changes in minimum temperature (T-min), maximum temperature (T-max), and precipitation (PRCP) for the three periods the 2020s (2011–2040), the 2050s (2041–2070), and the 2080s (2071–2100), with respect to the reference period 1981–2010 over Algeria focusing on a validation of the Statistical DownScaling Model (SDSM). In this approach, to underpin our analysis, we evaluate statistically the SDSM performance by simulating the historical temperatures and precipitation. The NCEP reanalysis data and CanESM2 predictors of three future scenarios, RCP2.6, RCP4.5, and RCP8.5 are used for model calibration and future projection, respectively. The projected climate changes resulting from the application of SDSM show a convincing consistency with those unveiled in previous studies over Algeria based on dynamical regional climate model outputs conducted in the context of Middle East-North Africa region. By the end of the century, the results exhibit strong warming for both extreme temperatures under the worst-case scenario (RCP 8.5), it is more pronounced for the T-max and over the Algerian Sahara region. Under the optimistic scenario (RCP2.6), the strength of the warming is expected to increase for both extreme temperatures. The projected changes of precipitation revealed for all scenarios several discrepancies with significant decrease over the northwest region and central Sahara, while nonsignificant change is projected for the center and eastern coastal regions. Our findings corroborate previous studies using sophisticated tools by demonstrating that Algeria’s climate is expected to warm further in the future. These primary findings could give an overview of the application of the statistical modeling approach using SDSM over a semi-arid and arid vulnerable region like Algeria and would extend our knowledge in the climate-modelling field for the North Africa zone by providing an added value to the existing GCMs and regional climate projections. In addition, reliable information regarding the magnitude of future changes at local scale may be used in impact models to assess changes of other key economic sector variables such as water resources management, energy and agriculture.

This study examined both long-term and short-term trends and fluctuations in rainfall and temperature over 34 meteorological stations located at seven regions in Bangladesh. Descriptive statistical analysis and Mann–Kendall trend test were utilized to investigate the variability of the rainfall and temperature of all stations in Bangladesh. Our research gave some insights into Bangladesh’s rainfall and temperature trends and variability.

One of the most serious challenges in the world is climate change. This study examines variations in seasonal and yearly fluctuations in extreme temperatures and precipitation in Ethiopia from 1987 to 2020 using 36 meteorological stations located in various climatic zones. The outcomes of the study demonstrated increased trends in the average annual maximum and minimum temperatures, with values of 0.094^∘C and 0.052^∘C, respectively. Despite falling trends in the summer, most stations experienced higher winter temperatures than summer. Furthermore, the analysis revealed a trend toward an increase in the number of rain stations over the summer season, while a trend toward a decrease in the amount of precipitation for a number of stations in the winter season; otherwise, large changes expected in the dega (cold), woina dega (cool), and kola (warm) climatic zones during the summer season did not occur. Precipitation activity has been near normal in most dega (cold), woina dega (cool), and kola (warm) climatic zones over the preceding 33 years. However, precipitation in the berha (hot) climatic zone was lower than average, with fluctuating levels noted throughout the year. The average annual precipitation has been decreasing at a rate of 0.146mm per year over the past 33 years, indicating that only the winter season has shown a downward (decreasing) trend, while the other three seasons, such as summer, spring, and autumn, have shown growing trends. Furthermore, Ethiopia’s average annual rainfall continues to be on a downward trend (decreasing).

As of today, mankind faces an existential threat in the form of climate change. The geological location and other anthropogenic occurrences make Pakistan rank among the top-10countries worldwide most affected by climate change and natural tragedies. This review provides an in-depth examination of the shifting patterns of temperature and precipitation in Pakistan, highlighting the significant impacts of climate change on the region. Significant differences in temperature have been reported in Pakistan, indicating that the maximum and minimum annual temperatures varied at the rates of 0.12–0.29°C/decade and 0.10–0.37°C/decade, respectively. Annual precipitation shows notable fluctuations over the decades, highlighting periods of both surplus and deficit; especially, precipitation in the year 2023 was 16% above the long-period average of 1961–2010 with 344.1mm. When the air temperatures continue to rise, it is imperative for Pakistan to enhance its resilience to climate change through improved infrastructure, sustainable agricultural practices, and effective water management. This study also reviews the disastrous effects of climate change on Pakistan, especially the recent occurrences of flooding and heatwaves.

This paper uses historical fluctuations of weather variables within counties in the People's Republic of China to identify their effects on economic growth from 1996 to 2012. We find three primary results. First, higher temperatures significantly reduce the growth rate of county-level gross domestic product per capita: an increase in the annual average temperature of 1°C lowers the growth rate by 1.05%–1.25%. The effect of higher temperatures is nonlinear. Second, fluctuations in temperature and precipitation not only have a level effect, they also have a substantial cumulative effect. Third, weather fluctuations have wide-ranging effects. Beyond their substantial effects on the growth rate of agricultural output, they also affect nonagriculture sectors, labor productivity, and investment. Our findings provide new evidence for the impact of weather changes on economic development and have major implications for adaptation policies.

Every year there are as many as 20,000 scientific papers and reports published about the science of climate and climate change, and the resulting impacts and policy implications. The vast majority of these publications are rigorously done and are peer reviewed before publication, Since about 1990, on a time scale of roughly every 4–6 years, top experts are being asked to assess the state of the science and the implications of the changes occurring in the climate. Internationally, this occurs through the Intergovernmental Panel on Climate Change (IPCC), and for the United States, through the US National Climate Assessments (NCAs). These assessments provide important input to policy considerations, at international, national, and local levels…