410 research outputs found

    Impulse magnetized magnetic screws

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    This paper is an investigation in the performance of two types of magnetic screws (MSs). The first is the magnet to magnet and consists of permanent magnet (PM) nut and PM screw and the second is a magnet to reluctance and consists of PM nut and a double-start reluctance screw. It is argued that for cost sensitive and long stoke applications, a magnet-to-reluctance MS may be the preferred option. It is also shown that capacitor discharge magnetization techniques can be employed for imprinting helical magnetization distributions on cylindrical PMs, significantly reducing the complexity and facilitating the practical realization of MS systems

    Obstacles towards the use of ICT tools in teaching of information & communication technology in Sri Lankan universities: special references to South Eastern University of Sri Lanka

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    Information and communication technologies (ICT) have become commonplace entities in all aspects of life. Across the past twenty years the use of ICT has fundamentally changed the practices and procedures of nearly all forms of endeavor within business and governance. Within education, ICT has begun to have a presence but the impact has not been as extensive as in other fields. This paper examines the obstacles toward the use of Information and Communication Technology (ICT) tools in teaching and learning Information and Communication Technology at Sri Lankan Universities specially focus on South Eastern University of Sri Lanka. The finding of a survey identify that the most significant obstacles are: ICT tools are changing too fast to keep current, extra time and effort needed after integrating ICT tools teaching and learning, the management did not provide any incentive for lecturers to integrate ICT tools in their teaching, the network connectivity was poor, the management did not have any evaluation in integration of ICT tools in teaching. Further, the paper provides a summary of the significant obstacles to implementing IT tools in teaching and learning ICT in Sri Lankan Universities and suggests some possible coping strategies to mitigate their effects on ICT tools implementation and this paper adopts analytical appraisal approach hence, reviews the development so far

    Synthesis of Anionic Surface Active Agents Containing Heterocyclic Moiety From Long Chain Fatty Alcohols

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    A series of novel groups of anionic surface active agent were synthesized. Synthesis of these surfactants via the reaction of long chain fatty alcohols (octyl, decyl and dodecyl) with maleic anhydride to give monoester. The monoester chloride reacted with amino derivatives of heterocyclic rings followed by addition of NaHSO3 .The surface tension, interfacial tension; Kraft point, emulsifying and wetting power were evaluated. Stability to hydrolysis, biodegradability and biological activities were measured. A comparison studies between the chemical structures and the results were done.  &nbsp

    Effect of planting methods of flax on garlic yield under different intercropping patterns

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    The purpose of this experiment was to investigate yield, yield components and economic evaluation of flax (Sakha 5) and garlic (Sids 40) under various planting methods and intercropping patterns. The experimental design was a split-plot design with four replicates. The main-plots were assigned to the three cultivating methods and the sub-plots were allocated to the four intercropping patterns. The results indicated that drilling as planting method achieved the highest values for most studied characters in both seasons for flax and garlic, except for number of cloves/plant and plant height in garlic. Intercropping system with low garlic density (100% flax + 12.5% garlic) produced the maximum values for stem diameter, straw yield, number of capsules and seed/plant, seed index and seed yield for flax and number of leaves and cloves/plant, head diameter and weight for garlic in both seasons. The highest bulb yield of garlic was achieved with intercropping 100% flax + 37.5% garlic in both seasons. It can be concluded that the most economic returns for both crops were obtained from drilling as planting method with intercropping pattern 100% flax + 37.5% garlic under the environmental conditions of North Delta of Egypt. Keywords: Intercropping, Land equivalent ratio (LER), Aggressivity (Ag), Relative crowding coefficient (RCC), economic evaluatio

    Seismic performance on stiffness and hysteresis loop of interior wall-slab joint for tunnel form building designs to British standard

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    Wall-slab is a system suitable for use in the field of high-rise building where the main load resisting system is in the form rigidly connected wall-slab member. This paper presents the performance of a full-scale wall-slab joint in tunnel form system subjected to lateral cyclic loading. The objectives are to determine seismic behavior on the hysteresis loops and stiffness. Interior wall-slab joint was tested up to failure drift of 1.5%. The biggest hysteresis loops were occurred at the closest to the double actuator. The stiffness of wall-slab joint started to decrease from 0.25% drift until 0.5% drift and lost it stiffness after 0.5% drift. Incretion of the percentage of reinforcement bars in the wall-slab and proper detailing at joint is required for seismic loading.Keywords: wall-slab; hysteresis; stiffness; joint; cycli

    Various characteristics of Ni and Pt–Al2O3 nanocatalysts prepared by microwave method to be applied in some petrochemical processes

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    AbstractAlumina-supported metal nanocatalysts were prepared via the microwave method, by loading nano Ni particles (at 1, 3 and 5wt%) or nano Pt particles (at 0.3, 0.6 and 0.9wt%). Structural and adsorption features of the nano catalysts were revealed through XRD, DSC-DTA, TEM, H2-chemisorption and N2-physisorption. N2-adsorption–desorption isotherms of type IV were related typically to mesoporous materials with H2 class of hysteresis loops characterizing ink bottle type of pores. The well dispersed nano-sized metal particles were evidenced in the studied catalytic systems, exhibiting marked thermal stability up to 800°C. The catalytic performances of different catalyst samples were assessed during cyclohexane, normal hexane and ethanol conversions, using the micro-catalytic pulse technique at different operating conditions. The 5% Ni–γ–Al2O3 sample was found to be the most active in dehydration of ethanol to produce ethylene, as well as in n-hexane cracking. However, the 1% Ni–Al2O3 sample showed the highest dehydrogenation activity for selective production of benzene from cyclohexane. On the other hand, the 0.9% Pt–γ–Al2O3 sample exhibited the highest activity in the dehydration of ethanol and in the dehydrogenation of cyclohexane. The 0.3% Pt–γ–Al2O3 sample was the most active in the dehydrocyclization of normal hexane, as compared to the other catalyst samples under study

    Combined versus single locoregional therapy in the treatment of unresectable hepatocellular carcinoma

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    AbstractIntroductionSurgical and locoregional therapies are different options in HCC treatment, several locoregional techniques are used.PurposeThis study aimed to assess the effectiveness of transarterial chemoembolization (TACE), radiofrequency ablation (RFA) and combined therapy, in HCC management.Materials and methodsThe study was conducted at our University Hospital, from August 2011 to February 2013. It included 60 patients with HCC (40 males and 20 females, age ranged between 45 and 70years). Patients were classified into 3 groups, group 1 treated with TACE, group 2 with RFA, and group 3 with both techniques. Response was assessed by triphasic CT and alpha fetoprotein. Patients were classified into good and poor responders after one and six months and one year. Patients’ survival and incidence of recurrence were recorded.ResultsThe percentage of good responders was greater with combined therapy than with TACE and RFA (90%, 70%, and 60% respectively). The overall survival was 75% and the recurrence free survival was 60% in TACE, 90%, and 45% in RFA and 95% and 90% in combined therapy respectively.ConclusionCombined therapy is superior regarding good response, overall survival, and free recurrence survival than either TACE or RFA alone

    A Simple Model for Cell Type Recognition Using 2D-Correlation Analysis of FTIR Images From Breast Cancer Tissue

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    Breast cancer is the second most common cancer after lung cancer. So far, in clinical practice, most cancer parameters originating from histopathology rely on the visualization by a pathologist of microscopic structures observed in stained tissue sections, including immunohistochemistry markers. Fourier transform infrared spectroscopy (FTIR) spectroscopy provides a biochemical fingerprint of a biopsy sample and, together with advanced data analysis techniques, can accurately classify cell types. Yet, one of the challenges when dealing with FTIR imaging is the slow recording of the data. One cm2 tissue section requires several hours of image recording. We show in the present paper that 2D covariance analysis singles out only a few wavenumbers where both variance and covariance are large. Simple models could be built using 4 wavenumbers to identify the 4 main cell types present in breast cancer tissue sections. Decision trees provide particularly simple models to reach discrimination between the 4 cell types. The robustness of these simple decision-tree models were challenged with FTIR spectral data obtained using different recording conditions. One test set was recorded by transflection on tissue sections in the presence of paraffin while the training set was obtained on dewaxed tissue sections by transmission. Furthermore, the test set was collected with a different brand of FTIR microscope and a different pixel size. Despite the different recording conditions, separating extracellular matrix (ECM) from carcinoma spectra was 100% successful, underlying the robustness of this univariate model and the utility of covariance analysis for revealing efficient wavenumbers. We suggest that 2D covariance maps using the full spectral range could be most useful to select the interesting wavenumbers and achieve very fast data acquisition on quantum cascade laser infrared imaging microscopes

    Management of congenital esophageal stenosis associated with esophageal atresia and its impact on postoperative esophageal stricture

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    Aim The aim of this work was to study the incidence, management of congenital esophageal stenosis (CES) associated with esophageal atresia (EA) and tracheoesophageal fistula (TEF), and its impact on esophageal stricture (ES) after primary repair.Patients and methods From January 2006 to December 2014, 41 sequential cases of EA with distal TEF were retrospectively studied. Cases with significant ES after primary repair were included in the study. Associated CES was diagnosed in the neonatal period by taking histopathologic samples from the tips of the esophageal pouches, failure to pass a size-6 nasogastric tube distally during primary repair, and by initial esophagogram.Results Significant ES developed in 19 patients (46.3%); of them, six had CES (32%). Three patients had tracheobronchial remnants at the anastomotic site. Two of them had refractory strictures requiring resections and one had mainly major esophageal dysmotility. Patients 4 and 5 had CES distal to the anastomotic site on initial esophagogram. Patient 4 responded well to dilatations, whereas the other one had refractory stricture. Patient 6 had distal CES due to fibromuscular stenosis diagnosed by failure to pass a size-6 nasogastric tube distally. The patient responded well to dilatation, myectomy, and Thal’s fundoplication.Conclusion One-third of the patients with significant stricture had CES; half of them were refractory to dilatation. Failure to have histology specimens and a high index of suspicion will make the incidence of this association a rarity. Diagnosis and management of CES with EA/TEF in the neonatal period is possible. Esophageal dilatation is the initial management for all cases with a low threshold for gastric fundoplication and gastrostomy. Resection is reserved for refractory stenosis.Keywords: congenital esophageal stenosis, esophageal atresia, esophageal stricture, tracheoesophageal fistul

    Effect of pesticides applied in cowpea production on rumen microbial fermentation of cowpea haulms as reflected in in vitro gas production

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    The present study assessed the effect of lambda cyhalothrin, cypermethrin and dimethoate residues in cowpea haulm on microbial fermentation using gas syringes as incubators. The lambda cyhalothrin, cypermethrin and dimethoate were applied at the vegetative, flowering and podding stages of the cowpea at the rate of 2.66 mg/L, 5.14 mg/L and 6.68 mg/L of water, respectively. Dimethoate was detected in the cowpea haulm at the highest concentration of 1.38 mg/kg. The haulm with no pesticide treatment was incubated with media containing rumen fluid, and pesticides were added at concentrations of 40 mg/kg, 80 mg/kg and 120 mg/kg. In vitro gas production was measured at 3 h, 6 h, 12 h, 24 h, 48 h, 72 h and 96 h to estimate the rate of gas evolution. Gas production in general was influenced by pesticide application. In general, gas evolution was reduced by increasing levels of lambda cyhalothrin up to 80 mg/kg. However, an increase in gas accumulation was observed with increasing levels of dimethoate, while the application of cypermethrin yielded no noticeable change in gas production. The study indicates that pesticide residues may function as toxins at concentrations greater than those encountered in the field or lethal dose (LD50) and may inhibit the growth of rumen microbes
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