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Go to Editorial ManagerHistorical records (1901–2021) of Iraq's air temperature and precipitation were studied and compared. A climatic multi-model ensemble and four emission scenarios with representative concentration pathways (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) are used in this research to explain the changes in future climate indicators in Iraq. The results showed a rise and decline in temperatures and precipitation over the past century, with an average of 1.3 °C and 57mm since 1901. A remarkable rise and decline in temperatures and precipitation occurred at 0.36 °C and 4mm per decade over the past thirty years (1990–2020). A greater increase in temperatures occurred in the southern regions than in the northern regions during summer. A temperature increase of 1.5 °C was observed in Basra City and 1.3 °C in Duhok City. The projected temperature over Iraq is higher than historical temperatures in all scenarios, with a rise of about 0.6°C every ten years. Days in June and September with temperatures exceeding 40 ºC have a greater probability of experiencing temperature increases. Iraq is expected to have a decrease in annual precipitation under the high emission scenarios of RCP8.5. The predictions of the medium emission scenarios RCP4.5 and RCP6.0 are noticeably different from the measurements of Iraqi weather stations, especially in 2006. Precipitation decreases from November to May from the historical period in high emission scenarios (RCP8.5) for the foreseeable future. Increased air temperatures and a lack of precipitation have significant effects on the ecosystem because of droughts and frequent dust storms. Therefore, the most important decision that senior management must make is the formulation of policies and procedures for water routing and storage.
A rapidly expanding global population has heightened the need for engineering technologies aimed to enhancing the mechanical properties of weak soil, raising concerns about the sustainability of engineering practices that depend on energy-intensive materials and methods from earlier times. Traditional ground improvement techniques like compaction, preloading, vibration, and chemical grouting are typically costly and frequently have very high energy and CO2 footprints. Soil stabilization employing bio-enzymes has been viewed as a resilient and ecologically beneficial method for modifying the soil characteristics. Calcite-induced precipitation methods have recently become potential techniques in geotechnical engineering for improving the shear strength of soils. One of the most promising methods among them is enzyme-induced calcite precipitation (EICP). Enzyme induced calcite precipitation (EICP) is a bio-inspired technique based on the precipitation of calcium carbonate for enhancing the geo-mechanical properties of soils. In this technique, calcium carbonate acts as a cementitious agent that binds the soil particles together at the points of contact hence, increasing the strength and stiffness of treated soils, while relatively reducing the soil permeability and porosity. The achieved enhancements make EICP useful for applications such as ground improvement, construction materials, and erosion control over traditional binders. It is an environmental friendly technique that has generated great interest to geotechnical engineers. EICP particularly, has proven to be more effective since its application to all soils coarse and fine which have small pore size. This review thoroughly assesses the use of the EICP approach as a soil stabilization strategy conducted by various researchers. This review article studies urease and its implication on the characteristics of treated soil such as shear strength, permeability and micro-structural changes.
The Mono and binary-mixed oxide catalysts were prepared by precipitation and co-precipitation method and investigated for the photocatalytic decolorization of orange G dye which was used as a pollutant model in this study. The structure of the synthesized catalysts were characterized by the X-ray diffraction (XRD), bonding by fourier transfer infrared (FTIR), morphology by scanning electron microscope (SEM) and reflection using UV-VIS diffuse reflectance spectra. The XRD results revealed that the mono oxide catalysts confirm well the cubic phase of cadmium and cerium oxide and that their mixed oxide catalyst i.e. 50Ce/25Cd show the same characteristic peaks of pure cerium oxide with slight shift to higher wave lengths for two crystalline peaks at 33.15° and 56.15° respectively. The FTIR spectra of 50Ce/25Cd mixed oxide catalyst improved the combination between both pure cadmium and cerium oxide catalyst. The diffuse reflectance showed a blue shift towards lower wave length and that the energy gap was increased with an increase in cerium content. Different reaction variables such as, effect of metal content, pH values, amount of hydrogen peroxide and effect of catalyst amount were studied to estimate their effect on the decolorization efficiency of orange G dye. The maximum catalytic activity achieved was 91% at a solution pH of 2.1, catalyst dosage of 1.5 g/L, 0.15 mL of H2O2 /100 mL of reaction volume and initial dye concentration of 10 mg/L after 60 min of reaction time.
Bio-cement built on microbial induced carbonate precipitation MICP, be able to consolidate the loose grains and can applied for soil reinforcement. In this study, the performing of an ureolytic Sporosarcina Pasteurii for sand stabilization was estimated. The S. Pasteurii Could effectively consolidates sand particles through urea hydrolysis and the successive production of calcite. The bio improved sands had relative great compressive strength after 60 days exposure to bacterial cells injections cycles. The compressive strength of bio stabilized sands was reliant on the utilized cell concentrations and density of urea and CaCl2. High bacteria cell masses decreased the compressive strength. The optimal density of cell, was OD600 0.5, when cost and performance were taken into account. The study shows that bio cementation of sand built on microbial induced carbonate precipitation (MICP) has ability for the reduction of sand permeability through pore clogging with precipitated carbonate.
Dyes are important chemicals in industrial uses; however, they are considered hazardous materials because they accompany sewage and are one of the causes of serious diseases such as cancer if not treated properly. The aim of this study is to specify the effect of dyes on the environment and human health and to remove them from water using the photochemical agent (polyoxometalate). By studying two types of Phosphotungstic acid (PTA) and phosphomolybdic acid (PMA) due to the good possibility of loading these acids on other materials using mixing and precipitation ways and without the need for high temperatures, as they are prepared at room temperature. They are also solid materials that are easy to separate, quickly dissolve in water, non-toxic, and do not release dangerous gases, which led to the need to use them in removing dyes, as they gave high efficiency. The research explains a comprehensive review of the use of PTA and PMA acid in Visible light-enhanced degradation of organic dye pollutants for three dyes: methylene blue, methyl orange and chromium B. Previous research is reviewed, with special emphasis on the performance of the photocatalyst, conditions that increase its efficiency, and the proposed mechanisms for the combined photocatalysts of PTA and PMA acids in developing the photocatalytic process. Finally, recent findings in this area are discussed, and possible future research continuations are suggested.