1,720,962 research outputs found
Finite element analysis of armor piercing bullet penetrating hard steel
Get PDFRMUTP Research Journal, Vol. 16, No. 2, July-December 2022, pp.171-186The bulletproof plates with materials that can convincingly be destroyed by the 7.62 mm bullet with its speed at 878 ± 9.1 m/s were developed by designing according to the National Institute of Justice Level 4 (NIJ 4). The plates were made of two flat sheets stacking, SKD11 and SUS304. Their components were composed of the front and back plates; the first sheet made of SKD11 material hardening at 65 HRC with a thickness of 6 mm and the back plate made of SUS 304 material with a thickness of 5 mm. The finite element method was applied to simulate and analyze the results to demonstrate the bullet resistance to the perforation by setting perpendicular sheet to the bullets. Therefore, the simulating studies for the bullet firing were demonstrated by locating its angles of 15, 30, 45 and 60 degrees to the SKD11 sheet with a thickness of 6, 8, and10 mm coupled with the SUS304 sheet with a thickness of 5, 6, 8, and 10 mm. These plates were stacking into two layers then the finite element method was applied to simulate one at a time. The results showed that the first sheet of SKD11 with 6 mm of thickness could resist the perforation of the bullet at 60 degree and the plate thickness of 8 and 10 mm could start resisting to the perforation at 45 degree. The second sheet of SUS304 with the thickness of 5, 6, 8, and 10 mm were incapable to resist to the perforation and the refraction of the bullet direction as good as that of SKD11. Therefore, the principle applying two metal sheets stacked into layers was essential to impel the resistance of the bullet perforation and change the direction of the bullet.Rajamangala University of Technology Phra Nakho
Fatigue Analysis and Design of reform using Finite Element Method
Get PDFรายงานวิจัย -- มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร,2553Rajamangala University of Technology Phra Nakho
การออกแบบเครื่องทดสอบการโก่งของคานยึดปลายแน่นสองข้างภายใต้แรงกระจายสม่ำเสมอ
Get PDFรายงานวิจัย -- มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร, 2555This research is designing and construction an apparatus of deflection of fixed end beam under uniformly distribution load. SolidWorks program is used for structure designing and CosmosWorks program is used for strength of structure analysis. Deflection and strain of beam were compared with the result of mathematical model according to function stress principal. Error of mathematical model result does not exceed 10%. Therefore, this apparatus can be used as prototype and produced for education purpose.Rajamangala University of Technology Phra Nakho
พอลิเอทิลีนน้ำหนักโมเลกุลสูงเชิงประกอบเพื่อความต้านทานการสึกหรอภายใต้การเปลี่ยนแปลงอุณหภูมิและสารหล่อลื่นสำหรับการนำไปประยุกต์ใช้งานทางด้านชิ้นส่วนเครื่องจักรกลอุตสาหกรรม
Get PDFรายงานวิจัย -- มหาวิทยาลัยเทคโนโลยีราชมงคลพระนคร, 2559The objective of this research is a study to determine optimum forming condition of
semi-finished bulk UHMWPE by using ram extruder that obtain maximum yield strength
and minimum wear rate for apply to use in area of medical and mechanical application.
Experimental extrusion specified forming condition consists of the temperature of 140, 150
and 160 ºC and pressure of 3, 5, 8 and 10 MPa with the temperature exposure time of 30
minutes. After known optimum forming condition of UHMWPE powder, thus forming
UHMWPE filled with different kind of filler to study and determine optimum weight fraction
of various types of filler that affect onto wear resistance property of UHMWPE composites.
Result, extruded condition at the temperature of 1 5 0 ºC under pressure of 5 MPa
with exposure time of 30 minutes is an optimum extruded condition due to specimen
shown a maximum yield strength, ultimate tensile strength and elongation of 20.43 ± 1.21
MPa, 28.33 ± 1.53 MPa and 285.60 ± 6.41 % respectively and obtain minimum wear rate
of 3.02 10-9 ± 5.27 10-10 mm3/Nm. Its mechanical properties and wear resistance
property higher than imported bulk UHMWPE by 23.3 % and 4.75 times respectively due
to the formation of cross-linking are occurred in polymer chain and also its degree of
crystallinity is high equal to 61.52%. For bulk UHMWPE, IR-spectrum shown a variation peak
of carbonyl group (C=O) are occurred that that it indicated the oxidation reaction at the
end of polymer chain and tis degree of crystallinity is equal to 53.31% which result to
decrease strength of polymer. In the case of UHMWPE filled with filler, optimum weight
fractions of various types of filler are as follows.
1. The filling of 0.3 wt. % Al2O3 particle size 0.05 μm shown yield strength, ultimate
tensile strength and elongation of 23.17 ± 3.35 MPa, 34.78 ± 2.80 MPa and 229.00 ± 6.09%
respectively that its mechanical properties was increased by 18.55% (increasing of ultimate
tensile strength). For the wear rate, is equal to 2.09 10-9 ± 3.39 10-10 mm3/Nm or its
wear resistance was increased by 1.44 times in compared with initial bulk UHMWPE.
2. The filling of 0.4 wt. % Al2O3 particle size 0.3 μm shown yield strength, ultimate
tensile strength and elongation of 21.93 ± 0.51 MPa, 25.40 ± 0.69 MPa and 267.67 ±
22.03% respectively that its mechanical properties was increased by 11.54% (increasing of
ultimate tensile strength). For the wear rate, is equal to 2.32 10-9 ± 4.78 10-10 mm3/Nm
or its wear resistance was increased by 1.30 times in compared with initial bulk UHMWPE.
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3 . The filling of 0.4 wt. % Al2O3 particle size 1 μm shown yield strength, ultimate
tensile strength and elongation of 23.93 ± 1.89 MPa, 26.77 ± 1.20 MPa and 296.54 ± 7.51%
respectively that its mechanical properties was increased by 5.83% (increasing of ultimate
tensile strength). For the wear rate, is equal to 2.14 10-9 ± 3.16 10-10 mm3/Nm or its
wear resistance was increased by 1.41 times in compared with initial bulk UHMWPE
4 . The filling of 4 wt. % Al2O3 particle size 5 μm shown yield strength, ultimate
tensile strength and elongation of 22.57 ± 2.01 MPa, 26.31 ± 3.11 MPa and 136.66 ±
11.67% respectively that its mechanical properties was increased by 7.68% (increasing of
ultimate tensile strength). For the wear rate, is equal to 2.37 10-9 ± 5.71 10-10 mm3/Nm
or its wear resistance was increased by 1.27 times in compared with initial bulk UHMWPERajamangala University of Technology Phra Nakho
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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