Comparison of methods for estimating loss from water storage by evaporation and impacts on reservoir management

Reservoirs are the key infrastructure of water resources management. A controlling variable of reservoir operation is evaporation, which in semi‐arid and arid regions may consume a large fraction of reservoir storage annually. This paper assesses the role of evaporation and the choice of evaporation methods on reservoir operation. The operation of the reservoir is calculated with the standard operation policy (SOP). Several efficiency criteria are employed to rank the evaporation‐calculation methods with the technique for the order of preference by similarity to ideal solution (TOPSIS). The method presented in this paper is illustrated by applying its application to Karkheh reservoir, the largest in Iran.     

Porous nanostructured ZnO films deposited by picosecond laser ablation

Porous nanostructured polycrystalline ZnO films, free of large particulates, were deposited by picosecond laser ablation. Using a Zn target, zinc oxide films were deposited on indium tin oxide (ITO) substrates using a picosecond Nd:YVO₄ laser (8 ps, 50 kHz, 532 nm, 0.17 J/cm²) in an oxygen atmosphere at room temperature (RT). The morpho-structural characteristics of ZnO films deposited at different oxygen pressures (150–900 mTorr) and gas flow rates (0.25 and 10 sccm) were studied. The post-deposition influence of annealing (250–550 °C) in oxygen on the film characteristics was also investigated. At RT, a mixture of Zn and ZnO formed. At substrate temperatures above 350 °C, the films were completely oxidized, containing a ZnO wurtzite phase with crystallite sizes of 12.2–40.1 nm. At pressures of up to 450 mTorr, the porous films consisted of well-distinguished primary nanoparticles with average sizes of 45–58 nm, while at higher pressures, larger clusters (3.1–14.7 μm) were dominant, leading to thicker films; higher flow rates favored clustering.     

碳酸盐岩核磁共振实验与认识

由于对碳酸盐岩核磁共振的测井响应一直缺乏系统的研究,使得该技术在一些复杂储层中的应用不能取得良好的效果。为此,基于大量的岩心核磁共振实验,分析了碳酸盐岩储层岩心的T2谱特征、移谱特征、差谱特征、T2截止值变化规律及核磁分析的孔渗参数与常规分析的孔渗参数之间的关系,并通过实验探索了基于孔隙结构特征来分析储层有效性的方法。研究表明:孔隙结构非均质性强的岩石移谱特征明显,对这类储层段不能简单地从有移谱现象便判定为气层;利用差谱法区别油气水层时,在发育大孔径孔隙的地层中,短等待时间测量需要有足够的等待时间;碳酸盐岩地层的T2截止值不是定值,与泥质含量成反比关系;高孔段核磁计算的孔渗参数的准确性明显地高于低孔段,并且核磁计算的渗透率主要反映的是基质渗透率,不能有效地反映裂缝渗透率。研究结果为核磁共振测井资料的采集及处理解释提供了有价值的实验依据。     

Influence of various plasma treatment on the properties of carbon nanotubes for composite applications

In present work, the effects of hydrogen and oxygen plasma treatments on the structural properties of carbon nanotubes (CNTs) synthesized by catalytic CVD (Chemical Vapor Deposition) have been systematically investigated. Field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy were used to characterize the microstructural changes of the CNTs. The oxygen plasma treatment resulted in that the nanoparticles were appeared at the surface of CNTs. At high r.f. power (300 Watt), the microstructure of CNT was changed from nanotube type to nano particles. Long plasma treatment time changed the CNT morphology dramatically. For hydrogen plasma, however, there was no change in microstructure of CNT From the Raman analysis, the crystallinity of CNT was deteriorated by the plasma treatment, regardless of plasma power, treatment time, and gas types. The CNTs treated in oxygen plasma for 90 min showed excellent dispersion properties in aqueous solution.     

Evaluation of polyphenolic fingerprints and antioxidant profiles of wild fruits

High‐performance thin‐layer chromatography and UV–vis spectrometry, coupled with multivariate exploratory techniques, have been investigated to fingerprint some local wild fruit extracts. The study was conducted using extracts of sea buckthorn (Hippophae rhamnoides), bilberry (Vaccinium myrtillus), cranberry (Vaccinium oxycoccos), rose hip (Cynosbati fructus), blackberry (Rubus fruticosus), raspberry (Rubus idaeus) and less‐known berries such as cornelian cherry (Cornus mas) and blackthorn (Prunus spinosa), all acquired from local markets. The extracts were firstly subjected to chromatographic separation coupled with digital image analysis and secondly to spectrophotometric analysis. Also, the DPPH˙ scavenging profiles were investigated through the UV–vis spectrum (200–700 nm), and RSA%–time profiles were determined for the first time using these samples, at different concentrations.     

The fcc/bcc phase transition in Fe<Subscript>x</Subscript>Ni<Subscript>100−x</Subscript> nanoparticles resolved by first-order reversal curves

One-pot polyol processing was successfully used for the preparation of Fe_xNi_100?x nanoparticles. By increasing Ni concentration in Fe_xNi_100?x alloy, the phase transition from bcc to fcc crystalline structure was clearly indicated by the XRD data as well as the measured hysteresis loops. FORC diagrams demonstrated that the prepared samples consist of single-domain magnetic particles with a uniform particle size. By changing the molar ratio of the precursors, different compositions of FeNi alloy were obtained. The influence of the temperature, solvent, surfactant, and amount of NaOH was also studied on the particle size, structure, and magnetic properties of the products.     

Modeling of composite fibrous porous diffusion media

To engineer the desired properties of fibrous porous media, a parametric modeling approach is needed to support the rational design of the materials before the fabrication. In this study, we propose a methodology that enables the accurate representation of three-dimensional (3D) microstructures of fibrous porous media and prediction of their transport properties. Toray TGP-H-060 gas diffusion layer (GDL) is selected as an example to demonstrate the feasibility of the suggested design methodology. The detailed microstructure of the GDL with the inclusion of locally distributed binder is constructed using an extended periodic surface (PS) modeling technique. A 3D morphological approach is taken to create the binder distribution within the fibrous microstructure. Transport properties including permeability, relative diffusivity, and tortuosity and local structure characteristics of the generated microstructure, under different binder loading are calculated. It is shown that the detailed model of the fiber-binder composite has a strong influence on the predicted properties.