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jih-328
Theoretical Design of Electrostatic Lens Accelerating and Decelerating Operated Under Different Magnification Conditions
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  In this paper,  design computationl investigation in the field of charged-particle optics with the aid of numerical analysis methods  under the absence of space charge effects. The work has been concentrated on the design of three-electrode  einzel electrostatic  lens accelerating and decelerating operated under different magnification conditions.     The potential field distribution of  lens has been represented by exponential function.  The paraxial-ray equation has been solved for the proposed field to determine the trajectory of charged-particles traversing in the lens.  From The axial  potential distribution and its first and second derivatives, the optical properties such as the focal length and the spherical and chromatic aberration coefficients have been computed, the electrode shape of lens has been determined by using SIMION computer program .     In this research , design electrostatic einzel lens three-electrode accelerating and decelerating L=2mm, 20mm operated under different magnification conditions (zero, infinite, finite). The electrode shape of the electrostatic lens was then determined from the solution of the Laplace's equation. The results showed low values of spherical and chromatic aberrations which are considered as good criteria for good design

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Publication Date
Fri Jan 01 2016
Journal Name
Journal Of Engineering
Theoretical and Experimental Stress Analysis of Cam With Simple Harmonic Motion
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Cams are considered as one of the most important mechanical components that depends the contact action to do its job and suffer a lot of with drawbacks to be predicted and overcame in the design process. this work aims to investigate the induced cam contact and the maximum shear stress energy or (von misses) stresses during the course of action analytically using Hertz contact stress equation and the principal stress formulations to find the maximum stress value and its position beneath the contacting surfaces. The experimental investigation adopted two dimensions photoelastic technique to analyze cam stresses under a plane polarized light. The problem has been numerically simulated using Ansys software version 15 as FE

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Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Experimental and Theoretical Investigation of Noise Effect in Centrifugal Fan Impeller
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In this work a study was made in centrifugal fan blower to investigate the effect of impeller blade design on sound pressure level (SPL). Shroud and unshroud impeller of nine blades are used. The sound generation from flow inside the test rig at different positions was displayed by using spectral analyzer. The experiments were carried out in anechoic chamber with small holes in its walls, under ambient condition about (25-27) C ° to avoid the effect of temperature on the sound pressure level. The results showed that (SPL) decreased with the increase of distance from the source about (3-4)dB when distance varied about (0.8-1.06)m, and the (SPL) decreased with the decrease of velocity about (8-12)dB when velocity varied between (13000-260

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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The effect of the dimensions of the strategic lens on achieving tax pioneer performance: Practical research in the General Authority for Taxes
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The aim of the research is to shed light on the dimensions of the strategic lens and its impact on achieving the pioneer tax performance and represented by the dimensions (strategic direction, growth, pilot indicator, renewal and modernization, efficiency and effectiveness) in the General Tax Authority. The questionnaire was adopted as a tool to collect data and information from the adult sample They are (91) who are on the site (Assistant Director General, Head of Division, First Division Deputy, Second Division Deputy, Division Officer, Division Officer Associate) The statistical program (SPSS) has been used to calculate (the mean, the standard deviation, the correlation coefficient, the difference coefficient, the F test, the

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Publication Date
Mon Jul 20 2020
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Performance of Two Species of Black Cumin (Nigella sativa L.) and (Nigella arvensis L.) Under Different Sowing Dates in Spring and Autumn at hallabja Governorate /Iraqi Kurdistan Region.
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     Two field experiments were performed to study the response of two species , Nigella sativa L. and Nigella arvensis L. within different sowing dates at spring and autumn seasons which included 1st and 20th March, 10th April and 1st May for spring season, while the sowing dates for the autumn season were, 2nd November, 21st November, 11th December, 31stDecember and 20thJanuary. Both experiments conducted according to the Completely Randomized Block Design (CRBD) within three replications at hallabja/Kurdistan Region, located [35°12'48.7"N; 45°57'34.4"

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Publication Date
Thu May 18 2023
Journal Name
Journal Of Engineering
Experimental and Modeling Study of Abrasive Wear of Tungsten Carbide Drilling Bit in Wet and Dry Conditions
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The results of theoretical and experimental investigations carried out to study the effect of load and relative sliding speed on the abrasive wear behavior in drilling bit teeth surfaces of an insert tungsten carbide bit have been presented. Experimentally, an apparatus for abrasive wear tests conducted on the modified ASTM-G65 was modified and fabricated to facilitate loading and measurement of wear rate for the sand/ steel wheel abrasion test, which involves two cases of contact; first is at dry sand and second is under wet condition. These tests have been carried under varied operating parameters of normal load and sliding speed. A theoretical model based upon the Archard equation has been developed for predicting wear simulation by u

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Crossref
Publication Date
Mon Aug 14 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Plant Phenology And Itsrelation TO The Cool Semi-Arid Conditions OF Sana'a
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In the cool semi-arid highland areas of Sana'a, a plant
phonological study of forty two species revealed that there was one
major outburst of plant emergence corresponding with the first period
of the heavy rainfall which take place during March-April. The second
period of heavy rainfall which takes place during July-August shows
moderate effect on emergence and growth.
Plant Species included annuals, biennials and perennials. Perennials
showed
the
following
growth
forms
hemicryptophytes,
chamaephytes, phanerophytes, and cryptophytes. Most plants where
herbaceous and a few where woody
Different Individuals of the same species could behave as annuals,
biennials or perennials. In areas where

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Publication Date
Tue Apr 18 2017
Journal Name
Transactions Of The Asabe
Effect of Drying Conditions on Triticale Seed Germination and Rice Weevil Infestation
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The combination of high protein content and a soft seed coat makes the wheat-rye hybrid Triticale (Triticosecale) vulnerable to attack by rice weevils. Drying triticale grain to moisture contents safe for storage can prevent infestation by rice weevils, but if grain is being stored for seed, high drying temperatures can affect seed germination. Grain can be effectively dried at low temperatures, but low-temperature drying is difficult in hot, humid regions such as the Gulf Coast. This study nvestigated the effects of drying temperatures from 35°C to 45°C on triticale seed germination and found no statistical differences between the germination rates of the seed at any of the drying temperatures and the germination rates of controls. Final

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Publication Date
Sat Dec 02 2023
Journal Name
Journal Of Engineering
Discussion on the Structural Design Index and Design Method of Widening and Splicing Lane of Old Asphalt Pavement
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The splicing design of the existing road and the new road in the expansion project is an important part of the design work. Based on the analysis of the characteristics and the load effect of pavement structure on splicing, this paper points out that tensile crack or shear failure may occur at the splicing under the repeated action of the traffic load on the new/old pavement. According to the current structure design code of asphalt pavement in China, it is proposed that the horizontal tensile stress at the bottom of the splicing layer and the vertical shear stress at other layers of the splicing line should be controlled by adjusting the position and size of the excavated steps in addition to the conventional design ind

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Publication Date
Thu Apr 01 2021
Journal Name
Iop Conference Series: Earth And Environmental Science
Theoretical structure of Eco-cities: subject review
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Given the importance of ecology and its entry into various fields in general and the urban environment particularly; ecological cities take wide ranges of application at multiple regional and global levels. However, it repeatedly noted that there was a state of cognitive confusion and overlapping in the term ecology comes from the diversity of implementation within several disciplines. Architects, designers, and planners have instilled biological development directly into the formal principles as well as the social structures of the ecological cities. Therefore, the research presents a rapid review of the most relevant areas that dealt with the ecological cities by research and analysis at various levels, from the concept and definition of

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Crossref (1)
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Publication Date
Thu Apr 01 2021
Journal Name
Iop Conference Series: Earth And Environmental Science
Theoretical structure of Eco-cities: subject review
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Abstract<p>Given the importance of ecology and its entry into various fields in general and the urban environment particularly; ecological cities take wide ranges of application at multiple regional and global levels. However, it repeatedly noted that there was a state of cognitive confusion and overlapping in the term ecology comes from the diversity of implementation within several disciplines. Architects, designers, and planners have instilled biological development directly into the formal principles as well as the social structures of the ecological cities. Therefore, the research presents a rapid review of the most relevant areas that dealt with the ecological cities by research and analys</p> ... Show More
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Scopus (4)
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