192,023 research outputs found

    Automated precision alignment of optical components for hydroxide catalysis bonding

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    We describe an interferometric system that can measure the alignment and separation of a polished face of a optical component and an adjacent polished surface. Accuracies achieved are ∼ 1μrad for the relative angles in two orthogonal directions and ∼ 30μm in separation. We describe the use of this readout system to automate the process of hydroxide catalysis bonding of a fused-silica component to a fused-silica baseplate. The complete alignment and bonding sequence was typically achieved in a timescale of a few minutes, followed by an initial cure of 10 minutes. A series of bonds were performed using two fluids - a simple sodium hydroxide solution and a sodium hydroxide solution with some sodium silicate solution added. In each case we achieved final bonded component angular alignment within 10 μrad and position in the critical direction within 4 μm of the planned targets. The small movements of the component during the initial bonding and curing phases were monitored. The bonds made using the sodium silicate mixture achieved their final bonded alignment over a period of ∼ 15 hours. Bonds using the simple sodium hydroxide solution achieved their final alignment in a much shorter time of a few minutes. The automated system promises to speed the manufacture of precision-aligned assemblies using hydroxide catalysis bonding by more than an order of magnitude over the more manual approach used to build the optical interferometer at the heart of the recent ESA LISA Pathfinder technology demonstrator mission. This novel approach will be key to the time-efficient and low-risk manufacture of the complex optical systems needed for the forthcoming ESA spaceborne gravitational waves observatory mission, provisionally named LISA

    Effect of fibre treatments on interfacial shear strength of hemp fibre reinforced polylactide and unsaturated polyester composites

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    Surface treatment of hemp fibres was investigated as a means of improving interfacial shear strength (IFSS) of hemp fibre reinforced polylactide (PLA) and unsaturated polyester (UPE) composites. Fibres were treated with sodium hydroxide, acetic anhydride, maleic anhydride and silane. A combined treatment using sodium hydroxide and silane was also carried out. IFSS of PLA/hemp fibre samples increased after treatment, except in the case of maleic anhydride treatment. Increased IFSS could be explained by better bonding of PLA with treated fibres and increased PLA transcrystallinity. The highest IFSS was 11.4 MPa which was obtained for the PLA/alkali treated fibre samples. IFSS of UPE/hemp fibre samples increased for all treated fibres. This is believed to be due to the improvement of chemical bonding between the treated fibres and the UPE as supported by FT-IR results. The highest IFSS (20.3 MPa) was found for the combined sodium hydroxide and silane treatment fibre/UPE samples

    Parametric Effect of Sodium Hydroxide and Sodium Carbonate on the Potency of a Degreaser

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    Experimental and statistical analysis was carried out on the comparative effect of sodium hydroxide and sodium carbonate on the potency of a laboratory produced degreaser in this work. The materials used include; octadecyl benzene sulphonic acid, sodium hydroxide, sodium carbonate, sodium metasilicate, carboxyl methyl cellulose (C.M.C), formadelhyde, perfume, colourant and distilled water. Different samples of degreaser were produced with varying composition of sodium hydroxide and sodium carbonate respectively. Statistical significance through methods like analysis of variance (ANOVA) of some parameters on various concentrations of sodium hydroxide and sodium carbonate was investigated. The effect of the varying compositions of sodium hydroxide and sodium carbonate was also determined by using a gray scale (GS) test, and also subjecting surfaces heavily stained with crude oil to determine and characterize the cleansing action of the degreaser. It was found that as the concentration of sodium hydroxide increases, the cleansing ability also increases, whereas the increase in concentration of sodium carbonate had no effect on the cleansing ability. The work would enable production of effective, useful and property controlled degreasers at moderate cost

    The Solubility of Wheat Gluten in Various Aqueous Solutions

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    Solubilities of vital wheat gluten in dilute solutions of sodium hydroxide, acetic acid, sodium carbonate, ethanol, and monoethanolamine at 55°C were determined. Solubilities at 30°C in dilute solutions of sodium hydroxide, acetic acid, monoethanolamine, and sodium borate were also determined. Sodium hydroxide, monoethanolamine, and acetic acid solutions were the best solvents

    Treatment of blueberries prior to freeze dehydration

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    Softening blueberry skin by treatment with weak solution of sodium hydroxide prior to freeze dehydration prevents tough, chewy skins upon rehydration

    Oxygen reduction at the silver/hydroxide-exchange membrane interface

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    A solid-state cell is used to study the electrocatalysis of oxygen reduction at the silver/hydroxide-exchange membrane interface. The catalyst/membrane interface exhibits improved performance in comparison to a catalyst/aqueous sodium hydroxide interface. Surprisingly, the half-wave potential for oxygen reduction is shown to shift 185 mV higher at the silver/hydroxide-exchange membrane interface than for the silver/aqueous hydroxide solution interface, and the exchange current density is significantly higher at 1.02 × 10−6 A m−2. On a cost per performance basis, silver electrocatalysts in a hydroxide-exchange membrane fuel cell may provide better performance than platinum in a proton-exchange membrane fuel cell. Keywords: Oxygen reduction reaction, Electrocatalyst, Alkaline membrane, Solid-state cell, Silve

    Effect of bleaching using sodium hydroxide on pulp derived from Sesbania grandiflora

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    World demand for paper is increasing. Short rotation pulpwood is needed. Sesbania grandiflora also known as Turi, is a fast growing and straight log species. The scholarly information of Turi as pulpwood are still limited. This paper aims to provide information of sodium hydroxide effect on the paper made from pulp derived from Turi. Sodium hydroxide is a common chemical using as part of full stage chemical bleaching in pulp industrial. Kraft pulp that produced using Turi, was bleached with sodium hydroxide at 3%, 6% and 9% based on pulp weight, respectively. Unbleached pulp was served as blank test. The optical and mechanical properties of handsheet paper made from bleached kraft pulp were evaluated according to TAPPI standard. The brightness and opacity of handsheet made from bleached pulp were improved with increasing the concentration of sodium hydroxide. The mechanical properties of handsheet were improved with using 3% sodium hydroxide and gradually decreased after 3% sodium hydroxide. In conclusion, sodium hydroxide is potential to improve optical properties of Turi pulp and improve the mechanical properties of paper made from Turi pulp at certain level. Excessive usage of sodium hydroxide brings adverse effect to mechanical properties of paper made from Turi pulp

    Synthesis of Copper Oxide Nanoparticles in Droplet Flow Reactors

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    Synthesis of metal oxide nanoparticles within droplet flow reactors is advantageous over batch synthesis due to the elimination of concentration and temperature gradients inside the reactor and prevention of reactor fouling. We present results on the synthesis of copper oxide nanoparticles using aqueous droplets of copper acetate and acetic acid inside a bulk stream of sodium hydroxide in 1-octanol. Varying the copper acetate, acetic acid, and sodium hydroxide concentration resulted in needle-like and plate-like nanoparticles of varying sizes. The rate of mass transfer from the bulk to the droplet phase was found to increase with flow rate and addition of surfactants

    EFFECT OF TEMPERATURE AND PARTICLE SIZE ON THE ALKALINE EXTRACTION OF PROTEIN FROM CHICKEN BONE WASTE

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    Chicken bone is a waste of chicken meat processing industry and restaurants that has not been used widely, even though it contains valuable organic compounds that are functionals, such as collagenous and non collagenous protein. This research was conducted to investigate the effect of temperature and particle size on the protein extraction from chicken bones using dilute sodium hydroxide solution. Controlled parameters in this study were the solvent in the form of sodium hydroxide solution, extraction time for 1 hour, pH 10.5, the ratio of chicken bone powder: solvent (1:4 w/v), and stirring speed 200 rpm. While the operating variables included the extraction temperature of 30C, 55C, and 80C, and particle size of 150 and 250 μm. Experiments were carried out by heating of 300 mL of sodium hydroxide solution with pH 10.5 in a three-necked flask equipped with Leibig condenser, thermometer, mechanical agitator and sampling device to reach the desired temperature (30C, 55C, and 80C). Then, a total of 75 g of chicken bone powders with desired particle size (150μm and 250μm) was introduced into the sodium hydroxide solution and the stirrer was operated at speed of 200rpm. At every 10 minutes interval, as much as 10 mL samples were withdrawn for total protein analysis using Lowry-Folin method. The experiment was terminated after 1 hour. The results show that both increase in temperature and particle size caused an increase in the amount of extracted protein. Highest concentration of protein extracted was achieved at 630.99 mg/L, when the extraction was carried out using 250μm bone particles and temperature 80oC
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