Large-scale replenishment of groundwater depletion by long-lived extreme rainstorms in arid regions: case study of the 2019 floods in Iran

The Dena rainstorm in Iran in March and April 2019 caused about US$ 8.3?×?10⁹ damage in the country; however, it resulted in the replenishment of half of the dam reservoirs and 35% of ponds and lakes. Also, it increased the volume of groundwater stored in aquifers by 3.6?×?10⁹ m³. In arid and semiarid regions such as most parts of Iran, which usually face water scarcity, getting water from rainstorms is essential for replenishing water resources. This research aims to quantify the direct and indirect effects of the Dena rainstorm on the replenishment of Iran’s groundwater storage using the groundwater balance method and water-table fluctuation method. Studies showed that the main mechanisms for replenishment of groundwater storage due to the rainstorm included increases in precipitation recharge, surface runoff recharge, and artificial recharge, and reductions in irrigation withdrawal and evapotranspiration, while the contribution of each factor is estimated to be about 23, 28, 2, 15, and 32%, respectively.

     

Numerical simulation of sedimentation process in reservoirs and development of a non-coupled algorithm to improve long-term modeling

This paper investigates the validity of a quasi-steady approximation for sediment transport and presents a new algorithm based on this concept. The developed non-coupled algorithm interacts among hydrodynamic, sediment, and morphology modules which are based on depth-averaged Navier-Stokes equations for the flow, the three-dimensional equation of conservation of sediment, and the mass balance between the bed and sediment (Exner equation) to simulate the reservoir sedimentation process. The non-coupled algorithm solves both the short-term scale and the relatively long-term scale problems of reservoir sedimentation. The proposed algorithm is verified using field data and by comparison with other accurate algorithms. Based upon the results of this investigation, the developed algorithm can be used to simulate long-term reservoir sedimentation while considerably decreasing the computational costs and preserving computational accuracy. The computational cost of the non-coupled algorithm is about 97% less than the conventional semi-coupled approach whereas the errors (Root Mean Square Error, Average Relative Error, and Maximum Relative Error of bed level) of the developed algorithm are approximately 15% greater than those for the semi-coupled algorithm for the average value.     

Paleofluid analysis from fracture-fill cements in the Asmari limestones of the Kuh-I-Mond field, SW Zagros, Iran

Kuh-I-Mond field in the Zagros foreland basin is a conventional heavy oil resource and is composed of fractured carbonates whose fractures were filled by calcite, dolomite, and anhydrite cements. Oil inclusions occurred within the fracture-fill cements indicate that fractures were open and played an active role during oil migration and charge. The highest measured values for secondary porosities belong to fractures in Asmari Formation, which is characterized by significant amounts of vug- and fracture-filling cements. Fractures facilitated fluid circulation and subsequently dissolution of allochems and high Mg carbonates. In contrast, fine-grained carbonate facies were less cemented, and thus, porosity enhancement by cement dissolution was insignificant. Temperature profiles of oil inclusions in the dolomite, calcite, and anhydrite minerals characterized by distinct variations in the homogenization temperatures (Th) that are divided into two ranges below 50°C in anhydrites and from 45°C to 125°C in dolomites and calcites. The lower Th ranges for anhydrite suggests that it may have formed at shallower burial depths during early to middle diagenesis. The oil inclusions display trend for increasing temperature downward which conform to Formation geothermal gradient. In other word, the decreasing trend of Th temperatures upward within Asmari Formation that can be observed in Th versus depth plot is consistent with the uplift events at Late Miocene time and later that caused removal of about 1,300 m of the crest of the Kuh-I-Mond anticline. Vitrinite reflectance data from source rock intervals in the field area do not support vertical migration of locally generated hydrocarbons into the Kuh-I-Mond accumulation, and long-distance lateral oil migration and charge from a source kitchen to the southwest is proposed. Vitrinite reflectance data from this dolomite and limestone reservoir suggest low maturation levels corresponding to paleotemperatures less than 50°C. The observed maturation level (<0.5% Ro) does not exceed values for simple burial maturation based on the estimated burial history. Also, homogenization temperatures from fluid inclusion populations in calcite and dolomites show expected good correlation with reflectance-derived temperatures. The Th data represent pore fluids became warmer and more saline during burial. As aqueous fluid inclusions in calcite veins were homogenized between 22°C and 90°C with a decrease in salinity from 22 to 18 eq.?wt.% NaCl. The Th values suggest a change in water composition and that dolomite and calcite cements might have precipitated from petroleum-derived fluids. The hydrocarbon fluid inclusions microthermometry data suggest that the reservoir was being filled by heavy black oils in reservoir during Cenozoic. Aqueous fluid inclusions hosted by calcite equant sparry/fossil cavity fills suggest low cementation temperatures (<45°C) and high salinities (19 eq.?wt.% NaCl), while those in dolostones are characterized by highly variable homogenization temperature (52°C to 125°C) and salinities (6.5 to 20 eq.?wt.% NaCl).     

Marine Bioactive Steryl Esters from the Red Sea Black Coral Antipathes dichotoma

Two new marine steryl hexadecanoates, 3β‐hexadecanoylcholest‐5‐en‐7‐one ( 1 ) and 3β‐hexadecanoylcholest‐5‐en‐7β‐ol ( 2 ), along with seven known compounds, cholest‐5‐en‐3β‐yl‐formate ( 3 ), thymidine ( 4 ), indole‐3‐carboxaldehyde ( 5 ), 3β‐hydroxycholest‐5‐en‐7‐one ( 6 ), cholesterol ( 7 ), 22‐dehydrocholestrol ( 8 ), and 24‐methylenecholesterol ( 9 ), were isolated from the anthozoan black coral, Antipathes dichotoma. The structures of all isolated compounds were determined by interpretation of their spectral data 1D (¹H, ¹³C and DEPT) and 2D (COSY, HSQC and HMBC) NMR, UV, IR, and MS. Compounds 1 – 5 were evaluated for their anticancer activities, employing four cancer panels; HepG2, WI 38, VERO, and MCF‐7. All tested compounds, except 4 , showed moderate activities. Compound 4 exhibited significant anticancer activity against VERO and MCF‐7, with IC₅₀ 20.5 and 20.2 µg/mL, respectively.     

Pt/十六烷基三甲基溴化铵纳米聚集体修饰玻碳电极促进析氢(英文)

A novel, cost-effective, and simple electrocatalyst based on a Pt-modified glassy carbon electrode(GCE), using cetyltrimethylammonium bromide(CTAB) as a cationic surfactant, is reported. Amphiphilic CTAB molecules were adsorbed on GCE by immersion in a CTAB solution. The positively charged hydrophilic layer, which consisted of small aggregates of average size less than 100 nm,was used for accumulation and complexation of [PtCl2. anions by immersing the electrode in Ksolution. The modified electrode was characterized using scanning electron microscopy,energy-dispersive X-ray spectroscopy, impedance spectroscopy, and electrochemical methods. The electrocatalytic activity of the Pt particles in the hydrogen evolution reaction(HER) was investigated.The results show that the CTAB surfactant enhances the electrocatalytic activity of the Pt particles in the HER in acidic solution.