1,038 research outputs found
School Smoking Policies and Health Science Students' Use of Cigarettes, Shisha, and Dipping Tombak in Sudan
Design And Development Of An Integrated Infield Collection-Transportation Machine For Oil Palm Fresh Fruit Bunch
A prototype oil palm FFB Collector-transporter was designed, developed,
modified and tested at the Department of Biological and Agricultural Engineering,
Universiti Putra Malaysia (UPM), Malaysia. This four-wheeled, hydrostatic drive,
integrated machine was designed for collecting and transporting oil palm fresh fruit
bunches in the field and unloading them directly into mainline transporters or trucks
at the roadside. The overall dimension of the machine was 4750 mm for length,
2040 mm for width and 2725 mm for height. The overall construction of the
machine was consisted of a main chassis and driving unit, collection assembly,
operator cab, scissors lift-type fruit bin and associated hydraulic control unit.
Various functional components of the machine were hydraulically operated through a
solenoid control system. ACAD2000 package was employed to develop the 3D
model of the prototype machine. A 29.8 kW @ 2200 rpm KUBOTA V2203-E 4-
cylinder diesel engine, a 2 1 .5 gpm @ 1000 rpm VICKERS TA1 919 main hydrostatic
pump, and a 14.5 gpm @ 1000 rpm SAMHYDRAULIC HIC55 driving motor were selected based on the computations made to determine the machine total engine
power and total hydraulic pressure requirements for the machine to operate under
local terrain conditions
Wind reduction patterns around isolated biomass for wind erosion control in a desertified area of Central Sudan
The aim of this study was to assess the effectiveness of sparse vegetation, feature common in arid zone, to reduce wind force (velocity) and hence protect the surface and regions downwind from drifting sand and their consequences. Respectively 4 (with heights h of 4, 3.2, 2 and 1.66 m), 2 (with h of 3 and 2.5 m) and 3 (with h of 1.04, 0.9 and 0.8 m ) well established single biomass configurations of Leptadenia pyrotechnica trees, Prosopis juliflora trees and Panicum turgidum grass, were selected in the field. Solar powered cup anemometer wind measurements with a data logger system were taken at heights of 0.25 and 0.5 h, at distances 0.5 and 1 h, at four sides of the tree in the prevailing wind direction and perpendicular to it, and additionally at 2, 4 and 6 h windward and leeward. The protection effectiveness of the biomass was calculated as a wind reduction ratio and in terms of objects protection, which was evaluated using the dimensionless protection index (É). The study showed that windward protection provided by Leptadenia and Prosopis at level 0.25h and distance 0.5 h was similar, w ith a wind reduction ratio R0.8, while Panicum showed comparably higher R-values. Even at the 0.5 h level, Panicum showed an R of 0.65 at 0.5 h distance. Leew ard, at 0.25 h level differences were small, R increasing from 0.6/0.7 to 0.8/1 with distance, Leptadenia protecting best. At higher level (0.5 h) at distances 0.5 and 1 h Prosopis gave better protection than the other two at distances 0.5, 1 and 2 h. The research is an exam ple of simple experimental work under difficult environmental conditions in Africa. It was part of studies in which additional attention was paid to quantification aspects under such conditions as well as to the problems it helped solve in the African societies concerned as agrometeorological service
The Effect of Impurities in Nickel Grain Boundary: Density Functional Theory Study
By means of density functional theory, we investigate the effect of impurities on structural, electronic and mechanical properties on Nickel Σ5 grain boundary (GB) and its free surface, by studying the effect of 11 transition metal impurities and 8 light elements. The calculation of segregation energy, cohesive energy, formation energy, GB embrittling potency and theoretical tensile strength combined helps us to give accurate conclusions about the effect of these impurities and to compare them with the available experimental and theoretical results. We used the obtained results that are on “equal footing” to establish some correlations and trends. We also confirmed that sulfur and oxygen are the most embrittling elements in Nickel GB in accordance with established literature results and that transition metal elements have a general tendency to segregate to the grain boundaries in a moderate way. Unlike the studied light elements, these elements tend to strengthen the Ni grain boundaries, especially W and Te
Impact of Contracted Endodontic Access Cavity Designs on Root Canal Disinfection Using Diode Laser: An in-Vitro Study
Abstract Introduction: New approaches for minimal invasive endodontic access cavity designs had been introduced for preserving the structural integrity of the offending tooth. Diode laser has been now widely used in root canal disinfection and showing highly promising results. Aim: to evaluate the impact of contracted endodontic access cavity designs on root canal disinfection using diode laser. Materials and Methods: Fifty-four intact freshly extracted human mandibular first molars were selected for the use in this study. Only the mesial roots of the selected samples were included in this study. Samples were randomly divided into three equal groups (n=18) according to the type of access cavity performed. Group (1): conventional access cavities, Group (2): Ninja access cavities, and Group (3): truss access cavities. Isolates of Enterococcus Faecalis (E.Fecacalis) were introduced in the root canals of the mesial roots of the selected samples. Samples were further sub-divided into two equal sub-groups (n=9) according to the disinfection method. Sub-group (a): Diode laser disinfection, and Sub-group (b): NaOCl 2.5% followed by EDTA 17% irrigation. Bacterial evaluation was performed using confocal laser scanning electron microscope. Results: The results showed that using Diode laser disinfection have shown higher bacterial reduction in comparison to NaOCl irrigation, but with no statistically significant difference. For access cavity designs, regardless of the type of disinfection used, conventional access cavities have shown the highest bacterial reduction, with the least bacterial reduction with Ninja access cavities. Conclusion: Contracted endodontic access cavities did not offer any advantages in comparison with the conventional endodontic access cavities regarding bacterial reduction. Diode laser can be used as an effective adjunct tool in root canal disinfection
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