Alkali release characteristics of blended cements

This paper presents results of an experimental program conducted to investigate the capacity of hydration products of different cementing materials to retain “bound” alkalis when the alkalinity of the surrounding solution drops. The study covered paste samples containing high-alkali Portland cement and various levels of silica fume and/or fly ash. The results showed that the ability of the hydration products of cement-fly ash systems to bind alkalis is a function of the CaO content of the fly ash, the binding increasing as the calcium content decreases. High-alkali fly ashes (Na₂O_e > 5.0% and CaO in the range of 15% to 20%) showed considerable amounts of alkali contributed to the test solutions. Silica fume does not have a high capacity to retain alkalis in its hydration products; however, ternary blends containing silica fume and fly ash have excellent capacity to bind and retain alkalis.     

Groundwater Utilization and Management in the State of Kuwait

Abstract

The main brackish groundwater resources in the State of Kuwait are the groundwater located in the Kuwait Group and the Dammam limestone aquifers. Most of the groundwater used in the State of Kuwait is for irrigation, some part of it is used for domestic purposes and for small scale industries. Since rainfall is seasonal and is less than the annual evaporation, the recharge from rainfall is negligible. Water levels in both the aquifers are highly affected by the pumping rate from each well. The groundwater is extracted heavily resulting in decline of water levels and the deterioration of groundwater quality though there is underflow from Saudi Arabia. Improvement of the groundwater management is essential for maintaining long-term productivity of the aquifers in the State of Kuwait.     

Inter-plant hydrogen integration with regeneration placement and multi-period consideration

Inter-plant hydrogen integration (IPHI) is getting more attention in recent years, as a result of the increasing demand for hydrogen in refinery processes, such as hydrotreating and hydrocracking. In this work, IPHI with regeneration scheme is analyzed. Indirect integration scheme is adopted, where hydrogen sources from different hydrogen networks are integrated via a centralized purifier, such as pressure swing adsorption (PSA) or membrane separation. The introduced model is able to select the optimum interception unit, which minimizes the total annualized cost. Besides, multi-period consideration is included in the analysis to address the effect of changes in operating conditions of the IPHI network on total hydrogen consumption. Two case studies are presented to demonstrate the applicability and usefulness of the proposed model.     

Hybrid Paper–Plastic Microchip for Flexible and High‐Performance Point‐of‐Care Diagnostics

A low‐cost and easy‐to‐fabricate microchip remains a key challenge for the development of true point‐of‐care (POC) diagnostics. Cellulose paper and plastic are thin, light, flexible, and abundant raw materials, which make them excellent substrates for mass production of POC devices. Herein, a hybrid paper–plastic microchip (PPMC) is developed, which can be used for both single and multiplexed detection of different targets, providing flexibility in the design and fabrication of the microchip. The developed PPMC with printed electronics is evaluated for sensitive and reliable detection of a broad range of targets, such as liver and colon cancer protein biomarkers, intact Zika virus, and human papillomavirus nucleic acid amplicons. The presented approach allows a highly specific detection of the tested targets with detection limits as low as 10² ng mL^?1 for protein biomarkers, 10³ particle per milliliter for virus particles, and 10² copies per microliter for a target nucleic acid. This approach can potentially be considered for the development of inexpensive and stable POC microchip diagnostics and is suitable for the detection of a wide range of microbial infections and cancer biomarkers.     

Nano-structured zinc oxide–cotton fibers: synthesis, characterization and applications

Zinc oxide nanoparticles were prepared and subsequently deposited onto the surface of the cotton fiber by ultrasonic irradiation. The optical, structure and morphology of the coated and un-coated cotton were examined by UV, fourier transform infrared spectroscopy, X-ray diffraction analysis (XRD) and scanning electron microscope (SEM)/Energy Dispersive X-ray analysis. XRD analysis revealed the presence of the crystalline metal oxide of hexagonal phase with an average crystallite size of 12 nm. These nanoparticles are probably physically adsorbed onto the cotton fiber surface. SEM analysis showed a distribution of ZnO nanorod assemblies of various diameters and lengths physically adsorbed onto the cotton fiber surface may take place. The ZnO-cotton fiber nano-composite were tested against Escherichia coli (gram negative) and Staphylococcus aureus (gram positive) cultures, and showed a significant antimicrobial activity.     

Characteristics and 3D formation of PVA and PEO electrospun nanofibers with embedded urea

The behavior of electrospun polyvinyl alcohol (PVA) and polyethylene oxide (PEO) nanofibers embedded with urea is studied as a function of various process parameters. Our results show that three‐dimensional nanofiber networks can be obtained when high concentrations of urea in the solution are used during electrospinning. The nanofibers are characterized using both scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The stability of the nanofiber as a function of electric field has also been studied. The successful formation of three‐dimensional nanofiber networks can open new trends toward applications in fertilizers containing nanofibers in the nanoagricultural field. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39840.     

Effects of processing on oxidative stability of sesame oil extracted from intact and dehulled seeds

Oxidative stability of oils extracted from intact and dehulled sesame seeds was determined by monitoring changes in fatty acid composition, iodine value (IV), peroxide value (PV), conjugated diene (CD), para-anisidine value (p-AV), and 2-thiobarbituric acid (TBA) value and by nuclear magnetic resonance spectroscopy after storage under Schaal oven conditions at 65°C for up to 35 d. The oils from coated seeds were more stable, as reflected in PV, CD, p-AV and TBA values, than those extracted from dehulled seeds after roasting at 200°C, steaming at 100°C, roasting at 200°C plus steaming, or microwaving at 2450 MHz, except for TBA values of oil from microwaved seeds. After 35 d of storage at 65°C, the CD, p-AV, and TBA values of extracted oil from dehulled microwaved seeds were 17.72, 10.20, and 1.22, respectively, while those of their coated counterparts were significantly (P<0.05) different at 14.20, 16.47, and 1.26, respectively. Few significant changes were evident in the fatty acid composition of oil obtained from either coated and dehulled seeds subjected to different treatments. Nuclear magnetic resonance analyses found that R_ao (aliphatic to olefinic protons) and R_ad (aliphatic to diallylmethylene protons) ratios increased steadily over the entire storage period, which indicated progressive oxidation of unsaturated fatty acids.     

Petrographical,Mineralogical, and Geochemical Studies on Core-samples From Sidi Salim-1 Well,Nile Delta,Egypt

Abstract

Core samples of sandstone and clay raised from the Neogene succession of Sidi Salim-1 well were petrographically, mineralogically, and geochemically studied with the objective of determining the depositional conditions.

The sandstone is composed of quartz, feldspars of which the deeper sands of Qawasim Formation show some alteration; with rock fragments of volcanic, metamorphic, and sedimentary origin, in addition to altered biotite. These components are embedded in amorphous pyrite, microcrystalline calcite, and primary dolomite, as well as partial cementation by gypsum (mainly in the Pliocene sands).

The clays are composed primarily of montmorillonite, kaolinite, and illite. These clays were provided from mafic igneous rocks, sedimentary rocks, and intermediate igneous rocks, and were deposited under reducing conditions in a brackish lagoon intermittently receiving varying amounts of fresh water.