150 research outputs found

    Economic comparison of tillage and planting operations in three tillage systems

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     To study the economy of tillage operations and present suitable systems for land preparation and planting, costs of execution of three different tillage operations in irrigated wheat crop were compared for three successive years.  The three systems include: conventional or maximum tillage (Max-till), reduced tillage (Red-till) using multitask machine, and using direct planting machinery to represent the no-tillage case (No-till).  Costs were composed of rental cost of tractor, the used implements, multitask machine and direct planting machine.  For each case, data were compared and analyzed in randomized block design.  The variance of wheat yield in the three tillage systems was significant at the 1% level.  Total costs per hectare were 109 and 78 and 46 Dollars for Max-till, Red-till and the No-till case, respectively.  Since, the test area under cultivation was part of a 200 hectare farm, crop protection and harvesting operations were carried out alike in the whole farm.  Accordingly, operations costs were estimated as 445 Dollars ha-1 tare.  Average yields of 7.85, 7.68, 5.2 t ha-1 were obtained, respectively, for Max-till, Red-till and No-till systems.  Since, the price per kg of wheat was equal to 0.36 Dollars ha-1, the profits of the harvest was equal to 2,271 Dollars ha-1 for the Max-till, 2,242 Dollars ha-1 for Red-till and 1,384 Dollars ha-1 for the No-till system.  In tillage and planting operations, usage of the reduce tillage system is offered as an alternative to the conventional tillage and no-till systems.  The Red-till system reduces fuel consumption, operation time, soil compaction due to decrease in the number of tractor trips, which leads to reduced production costs.  In addition, less investment in purchasing implements and preparation of the soil, which breaks the soil cohesion, are achieved with the reduced tillage system.   Keywords: costs of production, field performance, Max-till, Multitask machine, no-till, red-till, soil compaction

    Vibration analysis of a small diesel engine using diesel-biodiesel fuel blends

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    Biodiesel as an environmentally friendly fuel has the potential to provide comparable engine performance results.  Biodiesel is a renewable fuel produced from vegetable and seed oils, animal fats or waste edible oils.  Sound and vibration caused by the combustion process in the engine might have direct effects on users.   One of the important characteristics of diesel fuels is high noise and vibration.  The present study was carried out to examine the vibration of different diesel-biodiesel fuel blends in power tiller engine.  The main goal was to present fuels with the minimum vibration.  So, the time domain signals were analyzed in five levels of engine speed, three axes and six fuel blends on the engine.  The signal processing and statistical approach were applied for data analysis.  The results showed that in all engine speeds, the dominant frequency is matched to the piston stroke frequency of the engine, as well as the frequency of vibration with the increase of engine speed.  The experiments indicated that the magnitude of vibration in the power tiller engine depends on the axis of measurement, engine speed and the fuel blends.  Vibration acceleration is significantly affected by engine speed and the increase in forward speed due to the increase in vibration acceleration rms.  The results of the experiments revealed that vibration acceleration is significantly affected by the axis of measurement.  The magnitude of vibration acceleration in vertical axis was more than that in the other two axes and magnitude of vibration acceleration in the longitudinal axis was more than that in the lateral axis.  Fuel blends had significant effect on the vibration.  It demonstrated that B100, B5 and B20 have the lowest vibration.  On the contrary, B15 and B10 have the highest vibration.   Keywords: vibration analysis, power tiller, time domain, frequency domain, diesel-biodiesel fuel blend

    Exergy of a hybrid solar-wind reverse osmosis-MSF desalination system

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    A novel hybrid solar-wind reverse-osmosis (RO) multistage flash (MSF) distillation desalination system was manufac-tured and tested in actual conditions in Iran. Solar energy was used to provide both thermal and electrical power and wind energy was used to provide electrical power. Exergy analysis can be used to design more efficient energy systems by reducing inefficien-cies, and indicates opportunities for improving performance in existing systems. The exergy involved in the hybrid solar-wind RO-MSF desalination system is analyzed below using data obtained from theoretical and experimental studies. The RO and MSF systems, powered by wind and solar energy, achieved increases in the reliability and flexibility of the system and in the quality of the resulting drinking water. According to the exergy analysis, the irreversible losses from the hybrid solar-wind RO-MSF plant are concentrated in the solar collector and the multistage flash chamber. These exergy losses can be reduced by isolating the col-lector, coating the pipes and MSF walls, selecting the parameters for the vapor compressor and RO membrane and pumps, and improving the flash process. By optimizing the performance of the hybrid solar-wind RO-MSF system, the amount of water re-covery should increase, and the energy consumption should decrease, which should improve the overall efficiency of the system. Новая гибридная система многостадийной опреснительной (MSF) ректификационной опреснительной установки с использованием солнечного ветра (RO) была изготовлена ??и испытана в реальных условиях в Иране. Энергия ветра была необходима для обеспечения электрической энергии. Эксергетический анализ может быть использован для разработки более эффективных энергетических систем. Эксергия, задействованная в гибридной системе опреснения RO-MSF солнечного ветра, проанализирована ниже с использованием данных, полученных в результате теоретических и экспериментальных исследований.Системы RO и MSF, работающие от энергии ветра и солнца, гарантируют повышение надежности и гибкости системы. Согласно эксергетическому анализу, необратимые потери от гибридной установки RO-MSF с солнечным ветром сосредоточены в солнечном коллекторе и многоступенчатой ??испарительной камере. Эти параметры могут быть уменьшены за счет изоляции коллектора, покрытия труб и стен MSF, а также улучшения процесса вспышки. Оптимизирующая производительность гибридной системы RO-MSF мощность солнечного ветра должна увеличиваться, а потребление энергии должно снизиться, что должно повысить общую эффективность системы. и улучшение процесса прошивки.Оптимизирующая производительность гибридной системы RO-MSF мощность солнечного ветра должна увеличиваться, а потребление энергии должно снизиться, что должно повысить общую эффективность системы. и улучшение процесса прошивки. Оптимизирующая производительность гибридной системы RO-MSF мощность солнечного ветра должна увеличиваться, а потребление энергии должно снизиться, что должно повысить общую эффективность системы

    Experimental assessment of the histopathological effects of water-soluble fraction of crude oil on gill tissue of juvenile Rutilus frisii kutum

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    The toxic effects of water soluble fraction (WSF) of crude oil on the gills of juvenile kutum roach, Rutilus frisii kutum, were investigated. The juvenile (1-2g) kutum roach were collected in summer 2008 from the Kolmeh Hatchery Center, Golestan province, and acclimatized to laboratory conditions through keeping them in a 300 liter tank with de- chlorinated water for a minimum of 8 days. Six different types of WSF concentrations were made to obtain LC5096h including 27, 29.25, 31.5, 33.75, 36 and 38.25ppm. Then, 10 fingerlings of R. frisii kutum were exposed to the WSF concentrations, for 96 hours. Considering mortality rate of the juveniles in 96 hours and using Probit value statistical analysis, LC5096h was obtained at 33.95ppm. Two different concentrations (0.1 LC50 and LC50) of WSF were prepared for further assessments and after 24 and 96h of exposure, 3 individual fish were collected from each aquarium for histopathological studies. The gill sections with 3 micron thickness were prepared, stained using H & E, and examined by light microscope. General damages after observation included: Epithelial lifting, congestion in filament and lamellae, clubbing, fusion, hypertrophy of epithelial cells of lamellae, different levels of hyperplasia between lamella and aneurysms. Pathological studies showed that the WSF of crude oil causes serious damage in gills of juvenile R. frisii kutum, leads to malfunction of this organ which will harm homeostasis of the fish

    Application of autologous platelet-rich plasma (PRP) on wound healing after caesarean section in high-risk patients

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    Background: Platelet-rich plasma (PRP) is ahumanplasma product enriched by platelets, growth factors, and fibrinogen with high hemostatic and healing properties. Objectives: The aim of this study was to evaluate the effect of autologous PRP on wound healing in high-risk women undergoing cesarean sections. Patients and Methods: In this balanced, randomized, and controlled trial, 140 patients were admitted to Arash women�s hospital, Tehran, Iran from May of 2013 to November of 2014 for elective cesarean surgery. The patients were randomly assigned into two groups. The intervention group received PRP after surgery, whereas the control group received the usual care. All patients were evaluated at baseline, five days, and eight weeks after the cesarean section. The primary endpoint used the REEDA scale for assessing the changes in wound healing. The secondary outcome measures used were the Vancouver scar scale (VSS) and the visual analog scale (VAS). All scale scores were analyzed using a repeated measures test for variance. Results: At the end of study, the PRP group showed a greater reduction in the edema ecchymosed discharge approximation (REEDA) score compared to the control group (85.5 reduction in the PRP group; 72 in the control group) (P < 0.001). Compared with the control group, the PRP group had a significantly greater reduction in the VANscore, beginning on the fifth day after the cesarean section (-0.7, 38 reduction in PRP group;-0.8, 33 in control group) (P < 0.001), and this trend was stable at the end of the eighth week (-0.6, 54 reduction in PRP group;-0.3, 18 in control group). Furthermore, patients treated with PRP experienced a 93 reduction in the VAS score at the end of follow-up, but the control group only observed a 79 reduction (P < 0.001). Conclusions: It seems that applying PRP is an effective therapeutic approach for wound healing, and faster wound healing is expected due to the presence of more platelets and growth factors. © 2016, Iranian Red Crescent Medical Journal

    Characterization of a Drosophila Alzheimer's Disease Model: Pharmacological Rescue of Cognitive Defects

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    Transgenic models of Alzheimer's disease (AD) have made significant contributions to our understanding of AD pathogenesis, and are useful tools in the development of potential therapeutics. The fruit fly, Drosophila melanogaster, provides a genetically tractable, powerful system to study the biochemical, genetic, environmental, and behavioral aspects of complex human diseases, including AD. In an effort to model AD, we over-expressed human APP and BACE genes in the Drosophila central nervous system. Biochemical, neuroanatomical, and behavioral analyses indicate that these flies exhibit aspects of clinical AD neuropathology and symptomology. These include the generation of Aβ40 and Aβ42, the presence of amyloid aggregates, dramatic neuroanatomical changes, defects in motor reflex behavior, and defects in memory. In addition, these flies exhibit external morphological abnormalities. Treatment with a γ-secretase inhibitor suppressed these phenotypes. Further, all of these phenotypes are present within the first few days of adult fly life. Taken together these data demonstrate that this transgenic AD model can serve as a powerful tool for the identification of AD therapeutic interventions

    Genome-Wide Meta-Analysis of Five Asian Cohorts Identifies PDGFRA as a Susceptibility Locus for Corneal Astigmatism

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    Corneal astigmatism refers to refractive abnormalities and irregularities in the curvature of the cornea, and this interferes with light being accurately focused at a single point in the eye. This ametropic condition is highly prevalent, influences visual acuity, and is a highly heritable trait. There is currently a paucity of research in the genetic etiology of corneal astigmatism. Here we report the results from five genome-wide association studies of corneal astigmatism across three Asian populations, with an initial discovery set of 4,254 Chinese and Malay individuals consisting of 2,249 cases and 2,005 controls. Replication was obtained from three surveys comprising of 2,139 Indians, an additional 929 Chinese children, and an independent 397 Chinese family trios. Variants in PDGFRA on chromosome 4q12 (lead SNP: rs7677751, allelic odds ratio = 1.26 (95% CI: 1.16–1.36), Pmeta = 7.87×10−9) were identified to be significantly associated with corneal astigmatism, exhibiting consistent effect sizes across all five cohorts. This highlights the potential role of variants in PDGFRA in the genetic etiology of corneal astigmatism across diverse Asian populations
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