147 research outputs found
Merekabentuk dan Menilai Mesin Pelerai dan Penyisih Lada
Pepper (Piper nigrum L.) is an important cash crop in Malaysia, especially for the state of Sarawak. There are two major pepper products in international trade, white pepper and black pepper. This paper describes
the performance of a mechanized pepper thresher and sorter which was designed and nibricated at Universiti Pertanian Malaysia. The machine serves three main functions: detaching berries from the stalks, separating
detached berries from the empty stalks and separating large (> 5 mm diameter) and small berries for white and black pepper production, respectively. Tests were carried out to determine the optimum speed for threshing and sorting. The optimum operating speed for threshing was
found to be 700 rpm. At this speed, the average threshing capacity was 338 kg/h with threshing efficiency of 99%; damaged berries accounted for less
than 5%. The optimum operating speed for the sorting was found to be 280 rpm with the average sorting capacity of 415 kg/h
Selected pharmacokinetic issues of the use of antiepileptic drugs and parenteral nutrition in critically ill patients
<p>Abstract</p> <p>Objectives</p> <p>To conduct a systematic review for the evidence supporting or disproving the reality of parenteral nutrition- antiepileptic drugs interaction, especially with respect to the plasma protein-binding of the drug.</p> <p>Methods</p> <p>The articles related to the topic were identified through Medline and PubMed search (1968-Feburary 2010) for English language on the interaction between parenteral nutrition and antiepileptic drugs; the search terms used were anti-epileptic drugs, parenteral nutrition, and/or interaction, and/or in vitro. The search looked for prospective randomized and nonrandomized controlled studies; prospective nonrandomized uncontrolled studies; retrospective studies; case reports; and in vitro studies. Full text of the articles were then traced from the Universiti Sains Malaysia (USM) library subscribed databases, including Wiley-Blackwell Library, Cochrane Library, EBSCOHost, OVID, ScienceDirect, SAGE Premier, Scopus, SpringerLINK, and Wiley InterScience. The articles from journals not listed by USM library were traced through inter library loan.</p> <p>Results</p> <p>There were interactions between parenteral nutrition and drugs, including antiepileptics. Several guidelines were designed for the management of illnesses such as traumatic brain injuries or cancer patients, involving the use of parenteral nutrition and antiepileptics. Moreover, many studies demonstrated the in vitro and in vivo parenteral nutrition -drugs interactions, especially with antiepileptics.</p> <p>Conclusions</p> <p>There was no evidence supporting the existence of parenteral nutrition-antiepileptic drugs interaction. The issue has not been studied in formal researches, but several case reports and anecdotes demonstrate this drug-nutrition interaction. However, alteration in the drug-free fraction result from parenteral nutrition-drug (i.e. antiepileptics) interactions may necessitate scrupulous reassessment of drug dosages in patients receiving these therapies. This reassessment may be particularly imperative in certain clinical situations characterized by hypoalbuminemia (e.g., burn patients).</p
Preparation and characterization of ZnO/ZnAl₂O₄-mixed metal oxides for dye-sensitized photodetector using Zn/Al-layered double hydroxide as precursor
In this article, a simple new technique has been developed for the preparation of ZnO/ZnAl₂O₄-mixed metal oxide (MMO) as anode materials for visible light dye-sensitized (DS) photodetector using Zn/Al-layered double hydroxide (LDH) as precursor. Subsequently, a detailed correlation between the structural properties of the prepared samples and the photo-responsive behavior of the fabricated DS photodetectors was elucidated. Specifically, it is evidenced that a high surface area of the prepared mesoporous MMO anode materials exhibit excellent dye absorptivity and thus facilitate free electron transfer and increase the photocurrent in the fabricated DS photodetector. A significant bathochromic shift was observed in the optical energy of the prepared MMO samples under the increment of molar ratio, providing a short electron transfer pathway in the optimized Z7A DS photodetector, which in turn demonstrated photo-responsivity and photo-detectivity of 6 mA/W and 1.7 × 10⁺¹⁰ Jones, respectively. This work presents an alternative approach for the design of an eco-friendly MMO-based DS photodetector
UV-curable palm oil based-urethane acrylate/clay nanocomposites
Synthesis of palm oil based-urethane acrylate (POBUA) resins was carried out by acrylation of epoxidized palm oil (EPOP) using acrylic acid in the presence of a catalyst and followed by isocyanation to obtain the POBUA. Using the monomer as a diluent in the formulation, 4% of photoinitiator and incorporation of organoclay (1-5% wt), nanocomposites were obtained upon UV irradiation. The X-ray Diffractory XRD study revealed that the nanocomposites obtained were of the exfoliation type. The presence of the clay improved the hardness and did not affect the thermal stability. Similarly, it increased the glass transition temperature Tg but reduced the modulus as the clay content was increased. The improvement of the tensile strength was only obtained when the clay concentration was 5 phr
Strength Performance of Blended Ash Based Geopolymer Mortar
Geopolymer is a based on inorganic alumino-silicate binder system. Geopolymeric materials are formed using materials that containing silica and aluminium such as fly ash and rice husk ash, which activated by alkaline solution. This paper presents the study on the effect of replacement of SSA in RHA based geopolymer, types of curing and different molarity of NaOH used on the strength of Sewage Sludge Ash (SSA) and Rice Husk Ash (RHA) based geopolymer mortar incorporating with three (3) different mix proportions. Based geopolymer mortar was synthesized from treated sewage sludge and rice husk undergoing incineration process in producing ashes, activated with sodium silicate and sodium hydroxide solution by ratio of 2.5:1 and solution to ash ratio of 1:1. Molarity of 8M and 10M NaOH were used. The percentages of SSA replacement were 0%, 10% and 20% by weight. Compressive strength was conducted at age 7, 14 and 28 days to see the development of strength with two curing regimes, which are air curing and oven curing (60°C for 24 hours). From the research conducted, the ultimate compressive strength (6.28MPa) was obtained at zero replacement of SSA taken at 28 days of oven curing with 10M of NaOH. This shows that RHA, which is rich in silica content is enough to enhance the strength of geopolymer mortar especially with high molarity of NaOH
Influence of geometric shape on the deformation performance of natural jute/epoxy specimens under axial quasi-static compression
The interest in the using of natural composite has been increased significantly in recent years in many application of life due to their distinctive characteristics these like low density, high-energy dissipation ability, and fatigue resistance. Indeed, a seemingly good alternative candidate to metals.This work displays the deformation performance of two different types of geometrical natural composite shapes when subjected to uniaxial quasi-static loading. The purpose is to study the effect of geometrical on the progressive collapse of composite specimens. Two geometrical composite tubes have been fabricated by combination technique of manual lay-up and vacuum bladder moulding. The two types of the proposed tubes, which are the circular and corrugated shape. The experimental work was performed by using bidirectional jute fabric (with 3 layers and 100mm in length) and epoxy resin. Six patterns (three for each one) were tested and evaluated in the same conditions to provide a proper means of comparison between different geometric shapes. The result exhibited both kinds of samples demonstrated stable and progressive deformation with acceptable repeatability during the test process. It also showed the ability to absorb the higher energy of the corrugated samples configuration than the circular samples. Overall, the corrugated pattern configuration can be considered the optimal for crashworthiness structure application compared to a circular composite sample
Safety issues of capacitor banks in medium voltage systems
This paper describes and illustrates the important factors concerning the safety issues of capacitor banks in medium voltage (MV) power system networks. It also explains the protective issues that should be considered. A detailed account on failures and risks of capacitors during the switching operations in power distribution systems is presented. Procedures of safety, techniques of protection, existing solutions to avoid equipment damage, as well as maintaining system safety and reliability have been discussed
Electrodialysis membrane desalination for water and wastewater processing: irregular attack angles of membranes spacers
Electrodialysis desalination is constructed with a number of anion exchange membranes (AEM), cation exchange membranes (CEM), anode, cathode, adjacent silicon gasket integrated membrane spacers, and inlet/outlet holes per cell. At the boundary among an ionic solution and an ion exchange membrane, concentration polarization develops. Spacers placed in between channel’s walls function as stream baffles to increase turbulence, improve heat and mass transfer, diminish the laminar boundary layer, and lessen fouling problems. The current study offers a systematic review of membrane spacers, spacer-bulk attack angles, and irregular attack angles. Spacer-bulk attack angle is accountable for variations in the pattern and direction of stream which impact heat-mass transfer and concentration polarization. Irregular attack angles (e.g., 0°, 15°, 30°, 37°, 45°, 55°, 60°, 62°, 70°, 74°, 80°, 90°, 110°, 120°) in the present study were found to provide unique stream patterns due to the spacer’s filaments being less or more transverse in respect to the primary solution direction, which may significantly alter heat transfer, mass transport, pressure drop, and overall flow dynamics. Spacer applies shear stress resulting by continuous stream tangent to the membrane exterior, which lessens polarization. In the end, 45° is concluded as the preferred attack angle that offers balanced rates of heat transfer, mass transport, and pressure drop throughout the feed channel while greatly lowering the rate of concentration polarization
Synthesis of radiation curable palm oil-based epoxy acrylate: NMR, FTIR spectroscopic investigations
Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated
Utjecaj dugolančanog i razgranatog alkohola na mazivost estera na bazi dodekandiojske kiseline
Thirteen samples of esters based on dodecanedioic acid with different chemical structures were synthesized. Among these were di-2-octyl dodecanedioate, didecyl dodecanedioate, di-2-ethylhexanol dodecanedioate, di-2-ethylbutyl dodecanedioate, dioctyl dodecanedioate, dihexyl dodecanedioate, and dioleyl dodecanedioate. Diesters were synthesized through the esterification of dodecanedioic acid with selected long-chain and branched alcohols with acid catalyst of H2SO4. These esters were tested in terms of their suitability for application as lubricants. The results showed that the lubricity properties, based on their pour point, flash point, and oxidation stability of the esters were significantly affected by the linear and branched alcohols used. An excellent pour point property of di-2-ethylbutyl dodecanedioate and di-2-ethylhexanol dodecanedioate at −55 °C and −50 °C was observed compared to their respective same linear carbon number esters of dihexyl dodecanedioate at 10 °C and dioctyl dodecanedioate at 20 °C. These are due to the presence of the branched group in their molecule vicinity structure. However, the esters flash points were insignificantly affected by the presence of branched structure. The selected esters could be used for biolubricants or engine oil.
This work is licensed under a Creative Commons Attribution 4.0 International License.Sintetizirano je trinaest uzoraka estera na bazi dodekandiojske kiseline različitih kemijskih struktura. Među njima su bili di-2-oktil dodekandioat, didecil dodekandioat, di-2-etilheksanol dodekandioat, di-2-etilbutil dodekandioat, dioktil dodekandioat, diheksil dodekandioat i dioleil dodekandioat. Diesteri su sintetizirani esterifikacijom dodekandiojske kiseline s odabranim dugolančanim i razgranatim alkoholima s kiselinskim katalizatorom H2SO4. Ti su esteri ispitani u smislu njihove prikladnosti za primjenu kao maziva. Rezultati su pokazali da su na svojstva mazivosti, temeljena na njihovoj točki tečenja, točki zapaljenja i oksidacijskoj stabilnosti estera, znatno utjecali upotrijebljeni linearni i razgranati alkoholi. Uočeno je izvrsno svojstvo točke tečenja di-2-etilbutil dodekandioata i di-2-etilheksanol dodekandioata pri −55 °C i −50 °C u usporedbi s njihovim istim ravnopravnim esterima ugljikova broja diheksil dodekandioata pri 10 °C i dioktil dodekandioata pri 20 °C, zbog prisutnosti razgranate skupine u strukturi njihove blizine molekule. Međutim, prisutnost razgranate strukture neznatno je utjecala na točke zapaljenja estera. Odabrani esteri mogli bi se rabiti za biomaziva ili motorno ulje.
Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna
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