scholarly journals The Accuracy of the Dial Indicator of D-Type Shore Hardness Testers

1961 ◽  
Vol 27 (182) ◽  
pp. 1683-1686
Author(s):  
Kozo IIZUKA
Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 822
Author(s):  
Jy-Jiunn Tzeng ◽  
Tzu-Sen Yang ◽  
Wei-Fang Lee ◽  
Hsuan Chen ◽  
Hung-Ming Chang

In this study, five urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% HDD (594), and high-functional aliphatic UA (5812), were selected to formulate five UA-based photopolymer resins for digital light processing (DLP)-based 3D printing. Each UA (40 wt%) was added and blended homogenously with ethoxylated pentaerythritol tetraacrylate (40 wt%), isobornyl acrylate (12 wt%), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (3 wt%), and a pink acrylic (5 wt%). Each UA-based resin specimen was designed using CAD software and fabricated using a DLP 3D printer to specific dimensions. Characteristics, mechanical properties, and cytotoxicity levels of these designed UA-based resins were investigated and compared with a commercial 3D printing denture base acrylic resin (BB base) control group at different UV exposure times. Shore hardness-measurement data and MTT assays were analyzed using a one-way analysis of variance with Bonferroni’s post hoc test, whereas viscosity, maximum strength, and modulus were analyzed using the Kruskal–Wallis test (α = 0.05). UA-based photopolymer resins with tunable mechanical properties were successfully prepared by replacing the UA materials and the UV exposure times. After 15 min of UV exposure, the 5812 and 594 groups exhibited higher viscosities, whereas the 88A and 87A groups exhibited lower viscosities compared with the BB base group. Maximum flexural strength, flexural modulus, and Shore hardness values also revealed significant differences among materials (p < 0.001). Based on MTT assay results, the UA-based photopolymer resins were nontoxic. In the present study, mechanical properties of the designed photopolymer resins could be adjusted by changing the UA or UV exposure time, suggesting that aliphatic urethane acrylate has good potential for use in the design of printable resins for DLP-type 3D printing in dental applications.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.


2014 ◽  
Vol 699 ◽  
pp. 689-694 ◽  
Author(s):  
Mohd Zulkefli Selamat ◽  
Mohd Shakir Ahmad ◽  
Mohd Ahadlin Mohd Daud ◽  
Musthafa Mohd Tahir ◽  
Safaruddin Gazali Herawan

Polymer Electrolyte Membrane Fuel Cell (PEMFC) is an alternative energy system that has been verified with great potential for high power density, durability and cost effectiveness. Since the bipolar plate is the key component in PEMFC, the component must operate with multifunction and have a balance of properties, essentially well in both electrical and mechanical properties. At present, many different materials have been tested to be applied for bipolar plate in order to fulfill the balance in each property. In this work, the different material is tested and observed. Polypropylene (PP) is used as a binder material, Graphite (Gr) is used as a main filler and Carbon Black (CB), Iron (Fe) and Nickel (Ni) as the second filler. This composite is produced through compression molding and the effect of different filler material loading on the properties such as electrical conductivity, flexural strength, bulk density and shore hardness are observed. The result showed the increasing of electrical conductivity as the increased the CB and Fe loading. But for Ni, the result showed the decreasing of electrical conductivity as the loading of Ni has been increased. The targeted value also achieved for some certain degree of filler loading.


2018 ◽  
Vol 1 (1) ◽  
pp. 675-679
Author(s):  
Patrycja Pawłowska ◽  
Zbigniew Matuszak ◽  
Katarzyna Sosik ◽  
Mária Chovancová

Abstract Vulcanised rubber as a complex system is made from the basic component being virgin rubber and various components amounting to 10-15 per cent or even more. The material gains its most valuable properties in the final phase of processing i.e. vulcanisation. In mechanical as well as automotive engineering it is important for vulcanised rubber to be resistant to grease, oil and fuel in high operating temperatures. Being one of the very valuable isolation materials, vulcanised rubber is also characterised by dielectric and elastic properties as well as distinguished resistance to operating conditions (high/low temperature, weather conditions). All the above mentioned applications of vulcanised rubbers are also found in the shipyard industry. Their use is also very much predicated on the properties such as: ability to attenuate mechanical vibrations, high elasticity, considerable elastic deformability under static and dynamic loads, low permeability of water and gas, resistance to various chemicals, and other. The purpose of this article was to determine the hardness of vulcanised rubber samples obtained from various places on the “Izabel” inland barge. The scope of the study covered sampling and preparing the samples for testing (i.e. cleaning and degreasing the samples). Then, the hardness of the samples was measured using the Shore hardness test. The first part of the article presents the general concept of vulcanised rubber, its main components, properties, applications, and ageing. The second part focuses on the research scope and measuring the hardness of vulcanised rubber samples obtained from the “Izabel” inland barge.


Author(s):  
Dodi Sofyan Arief ◽  
◽  
Eko Jadmiko ◽  
Adhy Prayitno ◽  
Muftil Badri ◽  
...  

Dial indicator is a comparison device usually used in industrial activities, especially in production. To make measurements at this time must be supported by technology that can facilitate operators when using it and when analyzing measurement results. Involving the programme and microcontroller are a solution to developing in roundness measurement, and then the results can be more accurate or thorough between the readable values read from the measuring instrument with the actual value of varying the amount of data. Roundness application is a program that can input measurement data automatically and can do calculations directly. Then, it can display a reference circle, a table that calculates the values of X, Y, R, X’, Y’, R’, Roundness Deviation, Run out Concentricity or a shift in the center point and also the center point shift or Theta. In measuring roundness, the test object is used the Standard Mandrel which has been certified by PT. Global Quality Indonesia, by determining three points or positions, namely in the first position the amount of data is 180, in the second position the amount of data is 90 and in the third position, the amount of data is 60 with a rotating speed of 15 mm/s. The results of the reference circle can be seen in each calculation in each position, in the second position the roundness deviation values are approaching of the Mandrel.


Author(s):  
M. A. Kukharenko ◽  
V. A. Mokhoreva

The article presents various methods for determining the strength and plastic properties of the wire to assess the quality characteristics of the products produced in the steel shops of JSC «BMW – the Management Company of the Holding «BMC».The methods of determining the propensity of a thin wire to laminations by reversing the twisting («Swedish» twist) and unilateral twisting, fixing the length change of the sample with a prefix with the dial indicator are considered. The article describes the procedure and results of research to determine the effect of the ratio of the conditional yield strength to the time resistance of the rupture on the plastic properties of the wire, the type of tensile diagram of the wire fragility.


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