scholarly journals The Compositions: Biodegradable Material – Synthetic Resins as Moulding Sands Binders

2016 ◽  
Vol 16 (4) ◽  
pp. 75-78
Author(s):  
K. Major-Gabryś ◽  
A. Grabarczyk ◽  
St.M. Dobosz
Keyword(s):  
Thermal Deformation ◽  
Room Temperature ◽  
Bending Strength ◽  
Deformation Curve ◽  
Biodegradable Material ◽  
Technological Properties ◽  
Foundry Industry ◽  
Environmental Requirements ◽  
New Challenges ◽  
The Impact

Abstract Growing emission requirements are forcing the foundry industry to seek new, more environmentally friendly solutions. One of the solutions may be the technologies of preparing moulding and core sands using organic biodegradable materials as binders. However, not only environmental requirements grow but also those related to the technological properties of moulding sand. Advancing automation and mechanization of the foundry industry brings new challenges related to the moulding sands. Low elasticity may cause defects during assembly of cores or moulds by the manipulators. The paper presents the study of flexibility in the room temperature according to new method and resistance to thermal deformation of self-hardening moulding sands with furfuryl resin, containing biodegradable material PCL. The task of the new additive is to reduce the moulding sands harmfulness to the environment and increase its flexibility in the room temperature. The impact of the additive and the effect of the amount of binder on the properties of mentioned moulding sands were analysed. Studies have shown that the use of 5% of PCL does not change the nature of the thermal deformation curve, improves the bending strength of tested moulding mixtures and increases their flexibility at room temperature.

Study on Microwave Curing Behavior and Performance of Epoxy/Versamid 125

2012 ◽  
Vol 430-432 ◽  
pp. 281-284 ◽  
Author(s):  
Yun Bo Lei ◽  
Xue Juan Cao
Keyword(s):  
Room Temperature ◽  
Bending Strength ◽  
Good Condition ◽  
Curing Time ◽  
Epoxy System ◽  
Microwave Technology ◽  
Microwave Curing ◽  
And Performance ◽  
The Impact ◽  
Impact Ductility

The curing rate of epoxy/Versamid 125 (V125) by heating curing, room-temperature curing and microwave curing was compared. It is founded that applying microwave technology could effectively improve the curing rate and the curing time is only 3-4minutes. 140W microwave could cure the epoxy system in good condition, but 280W and 420W were easy to make the materials coking. The impact of diluent on mechnical properties of curing product were studied and it is showed that the impact strength increases and the impact ductility will be improved with the content of diluent increases, while the compressing strength, bending strength and tensile strength decrease.

scholarly journals Particle Impact Tests of Ceramic Gas Turbine Materials at Room Temperature

1996 ◽  
Author(s):  
Yasushi Hara ◽  
Keisuke Makino ◽  
Kenichi Mizuno ◽  
Toru Shimamori ◽  
Hiro Yoshida
Keyword(s):  
Impact Strength ◽  
Gas Turbines ◽  
Room Temperature ◽  
Bending Strength ◽  
Empirical Relationship ◽  
Rear Surface ◽  
Particle Impact ◽  
Threshold Velocity ◽  
Impact Tests ◽  
The Impact

In developing ceramic gas turbines (CGT), evaluation of impact strength of ceramic materials is one of the most important subjects. For the purpose of evaluating impact strength of ceramics, particle impact tests of ceramics are carried out at room temperature by using electrothermal (ET) gun and micro-sabot system. Power turbine nozzles and circular disk specimens made of three kinds of Si3N4 are impacted by samarium - cobalt (Sm - Co) magnet flyer particles in vacuum. Weight of particles is fixed to 4mg and particle velocities range from 300 to 900 m/sec. Thickness of specimens are 1.0, 1.5 and 2.0 mm. In this study critical impact velocity, Vc, is defined as threshold velocity which causes visible cracks on the rear surface of the impact side. The cracks seem to be brought by flexural fracture mode. It is found that Vc is related with bending strength, σ, and thickness, t, of the target material as : Vc = C · σ5/6 · t5/3. It is found that impact results with and without rear cracks are well categorized based on this empirical relationship.

Study on Mechanical Properties of PP Modified by β Nucleating Agent under the Low Temperature

2013 ◽  
Vol 710 ◽  
pp. 97-101
Author(s):  
Jiang Zhu ◽  
Xiang Liu ◽  
Qiang Xu ◽  
Liang Cao
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Room Temperature ◽  
Bending Strength ◽  
Nucleating Agent ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
X Ray ◽  
The Impact

The ethylene-propylene polymer (PP) was modified by using a rare earth β-nucleating agent (WBG-II). The crystallization characteristics of PP induced by WBG-II were investigated through the wide-angle X-ray diffraction (WAXD). The effect of β-nucleating agent on the mechanical property of PP under low temperature was also researched. The results confirmed that β-nucleating agent WBG-II can change the crystal structure of PP and induce the β-form crystals in the PP to develop. Moreover, under the room temperature, with the increment of WBG-II, the tensile strength, bending strength and modulus of the modified PP increase, but the impact strength and elongation at break decrease; and especially at-10 °C, this tendency is more obvious.

PODC 2020 Review

2021 ◽  
Vol 51 (4) ◽  
pp. 75-81
Author(s):  
Ahad Mirza Baig ◽  
Alkida Balliu ◽  
Peter Davies ◽  
Michal Dory
Keyword(s):  
Machine Learning ◽  
Distributed Computing ◽  
Keynote Speaker ◽  
Lively Discussion ◽  
Theoretical Understanding ◽  
New Directions ◽  
New Ideas ◽  
New Challenges ◽  
The Impact ◽  
Distributed Machine Learning

Rachid Guerraoui was the rst keynote speaker, and he got things o to a great start by discussing the broad relevance of the research done in our community relative to both industry and academia. He rst argued that, in some sense, the fact that distributed computing is so pervasive nowadays could end up sti ing progress in our community by inducing people to work on marginal problems, and becoming isolated. His rst suggestion was to try to understand and incorporate new ideas coming from applied elds into our research, and argued that this has been historically very successful. He illustrated this point via the distributed payment problem, which appears in the context of blockchains, in particular Bitcoin, but then turned out to be very theoretically interesting; furthermore, the theoretical understanding of the problem inspired new practical protocols. He then went further to discuss new directions in distributed computing, such as the COVID tracing problem, and new challenges in Byzantine-resilient distributed machine learning. Another source of innovation Rachid suggested was hardware innovations, which he illustrated with work studying the impact of RDMA-based primitives on fundamental problems in distributed computing. The talk concluded with a very lively discussion.

Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel

2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Spark Plasma Sintering ◽  
High Speed ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Speed Steel ◽  
Continuous Heating ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

The Impact of COVID-19: Democracy in the Time of a Pandemic

Social Change ◽  
2021 ◽  
Vol 51 (4) ◽  
pp. 475-482
Author(s):  
Zoya Hasan
Keyword(s):  
Social Sciences ◽  
Human Rights ◽  
Social Development ◽  
Health Crisis ◽  
Domain Experts ◽  
Sharp Focus ◽  
The World ◽  
Democratic Rights ◽  
New Challenges ◽  
The Impact

The recent spread of the delta variant of the COVID-19 pandemic in many countries, though uneven, has once again set alarm bells ringing throughout the world. Nearly two years have passed since the onset of this pandemic: vaccines have been developed and vaccination is underway, but the end of the campaign against the pandemic is nowhere in sight. This drive has merely attempted to adjust and readjust, with or without success, to the various fresh challenges that have kept emerging from time to time. The pandemic’s persistence and its handling by the governments both have had implications for citizens’/peoples’ rights as well as for the systems which were in place before the pandemic. In this symposium domain experts investigate, with a sharp focus on India, the interface between the COVID-19 pandemic and democracy, health, education and social sciences. These contributions are notable for their nuanced and insightful examination of the impact of the pandemic on crucial social development issues with special attention to the exacerbated plight of society’s marginalised sections. In India, as in several other countries, the COVID-19 pandemic has affected democracy. The health crisis came at a moment when India was already experiencing democratic backsliding. The pandemic came in handy in imposing greater restrictions on democratic rights, public discussion and political opposition. This note provides an analysis and commentary on how the government’s response to the COVID-19 pandemic impacted governance, at times undermining human rights and democratic processes, and posing a range of new challenges to democracy.

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