Optimization of Deformable-Adhesive Application on the Chip-Apply Process

2006 ◽  
Vol 514-516 ◽  
pp. 848-852
Author(s):  
Isabel Macedo ◽  
Marta C. Oliveira ◽  
André Cardoso
Keyword(s):  
Plastic Deformation ◽  
Deformation Behaviour ◽  
Chemical Characteristics ◽  
Mechanical Compression ◽  
Air Atmosphere ◽  
Higher Temperature ◽  
Deformation Level ◽  
Adhesive Application ◽  
The Impact ◽  
Dsc Curves

A study on the impact of batch-to-batch variability of a commercial wet adhesive on its plastic deformation behaviour is here presented. In the chip-apply process, a controlled and stable plastic deformation under thermal-mechanical compression is expected after the first of a two-step curing, named pre-cure. Wet adhesive batches rheological, mechanical and chemical characteristics are available but no information on deformation behaviour is provided. Different pre-curing recipes and oven atmospheres were tested and the plastic deformation was induced by applying pre-defined thermo-compression parameters. Results indicate that shorter pre-cure cycles at higher temperature, under air atmosphere, reduce batch-to-batch deformation variability. DSC curves support these findings. A correlation between deformation level and rheological properties could also be observed, which can be very useful in the triage of adhesive batches for specific process parameters window.

scholarly journals Impact of temperature and relative humidity on the transmission of COVID-19: a modelling study in China and the United States

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043863
Author(s):  
Jingyuan Wang ◽  
Ke Tang ◽  
Kai Feng ◽  
Xin Lin ◽  
Weifeng Lv ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Relative Humidity ◽  
Human Mobility ◽  
The United States ◽  
Reproductive Number ◽  
Cross Sectional ◽  
The Usa ◽  
Higher Temperature ◽  
Potential Impact ◽  
The Impact

ObjectivesWe aim to assess the impact of temperature and relative humidity on the transmission of COVID-19 across communities after accounting for community-level factors such as demographics, socioeconomic status and human mobility status.DesignA retrospective cross-sectional regression analysis via the Fama-MacBeth procedure is adopted.SettingWe use the data for COVID-19 daily symptom-onset cases for 100 Chinese cities and COVID-19 daily confirmed cases for 1005 US counties.ParticipantsA total of 69 498 cases in China and 740 843 cases in the USA are used for calculating the effective reproductive numbers.Primary outcome measuresRegression analysis of the impact of temperature and relative humidity on the effective reproductive number (R value).ResultsStatistically significant negative correlations are found between temperature/relative humidity and the effective reproductive number (R value) in both China and the USA.ConclusionsHigher temperature and higher relative humidity potentially suppress the transmission of COVID-19. Specifically, an increase in temperature by 1°C is associated with a reduction in the R value of COVID-19 by 0.026 (95% CI (−0.0395 to −0.0125)) in China and by 0.020 (95% CI (−0.0311 to −0.0096)) in the USA; an increase in relative humidity by 1% is associated with a reduction in the R value by 0.0076 (95% CI (−0.0108 to −0.0045)) in China and by 0.0080 (95% CI (−0.0150 to −0.0010)) in the USA. Therefore, the potential impact of temperature/relative humidity on the effective reproductive number alone is not strong enough to stop the pandemic.

scholarly journals Optimal Solutions for the Use of Sewage Sludge on Agricultural Lands

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 585
Author(s):  
Catalina Iticescu ◽  
Puiu-Lucian Georgescu ◽  
Maxim Arseni ◽  
Adrian Rosu ◽  
Mihaela Timofti ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Agricultural Production ◽  
Agricultural Land ◽  
Chemical Characteristics ◽  
Optimal Solutions ◽  
Physico Chemical ◽  
Agricultural Areas ◽  
The Impact ◽  
Made In

The use of sewage sludge in agriculture decreases the pressure on landfills. In Romania, massive investments have been made in wastewater treatment stations, which have resulted in the accumulation of important quantities of sewage sludge. The presence of these sewage sludges coincides with large areas of degraded agricultural land. The aim of the present article is to identify the best technological combinations meant to solve these problems simultaneously. Adapting the quality and parameters of the sludge to the specificity of the land solves the possible compatibility problems, thus reducing the impact on the environment. The physico-chemical characteristics of the fermented sludge were monitored and optimal solutions for their treatment were suggested so as to allow that the sludge could be used in agriculture according to the characteristics of the soils. The content of heavy metals in the sewage sludge was closely monitored because the use of sewage sludge as a fertilizer does not allow for any increases in the concentrations of these in soils. The article identifies those agricultural areas which are suitable for the use of sludge, as well as ways of correcting some parameters (e.g., pH), which allow the improvement of soil quality and obtained higher agricultural production.

Effect of Grain Size on Deformation Twinning Behavior of Ti6Al4V Alloy

2015 ◽  
Vol 830-831 ◽  
pp. 337-340
Author(s):  
Ashish Kumar Saxena ◽  
Manikanta Anupoju ◽  
Asim Tewari ◽  
Prita Pant
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Behaviour ◽  
Air Cooling ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Β Phase ◽  
Plastic Deformation Behavior

An understanding of the plastic deformation behavior of Ti6Al4V (Ti64) is of great interest because it is used in aerospace applications due to its high specific strength. In addition, Ti alloys have limited slip systems due to hexagonal crystal structure; hence twinning plays an important role in plastic deformation. The present work focuses upon the grain size effect on plastic deformation behaviour of Ti64. Various microstructures with different grain size were developed via annealing of Ti64 alloy in α-β phase regime (825°C and 850°C) for 4 hours followed by air cooling. The deformation behavior of these samples was investigated at various deformation temperature and strain rate conditions. Detailed microstructure studies showed that (i) smaller grains undergoes twinning only at low temperature and high strain rate, (ii) large grain samples undergo twinning at all temperatures & strain rates, though the extent of twinning varied.

Study on the Impact of Fine-Blanking with Negative Clearance on the Materials Microstructure and Hardness

2010 ◽  
Vol 97-101 ◽  
pp. 149-152
Author(s):  
W.F. Fan ◽  
J.H. Li ◽  
Zhong Mei Zhang
Keyword(s):  
Plastic Deformation ◽  
Research Result ◽  
Original Material ◽  
Fine Blanking ◽  
Complicated Process ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
Negative Clearance ◽  
The Impact ◽  
1045 Steel

The Fine-blanking with negative clearance processing is very complicated process because the blanking clearance is negative clearance, for this reason, the state of stress and strain in sheet inside are also more complicated than conventional blanking. In the process of fine-blanking with negative, plastic deformation of the material is fiercer than conventional blanking, and the change of material inner structure and hardness is more intense because of plastic deformation. The deformation principle of fine-blanking deformation with negative clearance is analyzed by means of streamline and metallographic photograph and micro hardness. The impact of fine-blanking with negative clearance on the materials microstructure and hardness is discussed. The research result indicates that the hardening value is 1.8 times than original material itself and the maximum harden depth is 2.2mm for AISI-1045 steel in the process of blanking with negative clearance. Therefore, it could enhance fatigue strength and the working life of workpiece greatly because of the improvement of the material inner structure.

Effect of Tensile Strain on Performance Parameters of Different Structures of MoS2 Monolayer

2021 ◽  
Author(s):  
Priya kaushal ◽  
Tarun Chaudhary ◽  
Gargi Khanna
Keyword(s):  
Tensile Strain ◽  
Computational Study ◽  
Level Structure ◽  
Charge Carriers ◽  
Performance Parameters ◽  
Mos2 Monolayer ◽  
Higher Temperature ◽  
Silicon Doped ◽  
The Impact ◽  
Biaxial Tensile Strain

Abstract The present work is based on the computational study of MoS2 monolayer and effect of tensile strain on its atomic level structure. The bandgap for MoS2 monolayer, defected MoS2 monolayer and Silicon-doped monolayer are 1.82 eV (direct bandgap), 0.04 (indirect bandgap) and 1.25eV (indirect bandgap), respectively. The impact of tensile strain (0-0.7%) on the bandgap and effective mass of charge carriers of these three MoS2 structure has been investigated. The bandgap decrease of 5.76%, 31.86% and 6.03% has been observed in the three structures for biaxial strain while the impact of uniaxial strain is quite low. The impact of higher temperature on the bandgap under biaxial tensile strain has been also analyzed in this paper. These observations are extremely important for 2D material-based research for electronic applications.

Plastic Deformation Behaviour of Fe-Cu Composites

2008 ◽  
pp. 63-76
Author(s):  
Y. Schneider ◽  
A. Bertram ◽  
T. Böhlke ◽  
C. Hartig
Keyword(s):  
Plastic Deformation ◽  
Deformation Behaviour

Study on Evolution of Plastic Deformation of Brass Band under Impact Load

2017 ◽  
Vol 753 ◽  
pp. 222-227
Author(s):  
Jun Hui Yin ◽  
Chao Xiong ◽  
Hui Yong Deng ◽  
Yan Long Zhang
Keyword(s):  
Plastic Deformation ◽  
Growth Stage ◽  
Impact Load ◽  
Recrystallization Process ◽  
Brass Band ◽  
Sexual Characteristics ◽  
Surface Metal ◽  
Band Deformation ◽  
The Impact ◽  
Meso Scale

During the moving stage of the projectile, the impact load produced by the detonation of the explosive powder acts on the ribbon, causing the plastic band deformation to occur rapidly and the surface temperature rapidly increases. In this paper, the evolution mechanism of the plastic deformation of brass band is studied, and the recrystallization process of the surface metal is still at the meso-scale scale. The recrystallization and grain growth stage sexual characteristics.

Elaboration of Architectured Copper Clad Aluminium Composites by a Multi-Step Drawing Process

2018 ◽  
Vol 941 ◽  
pp. 1914-1919
Author(s):  
Florent Moisy ◽  
Antoine Gueydan ◽  
Xavier Sauvage ◽  
Clément Keller ◽  
Alain Guillet ◽  
...  
Keyword(s):  
Image Processing ◽  
Plastic Deformation ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Wire Drawing ◽  
Al Composite ◽  
Microscopy Image ◽  
Deformation Level ◽  
Different Diameters ◽  
Drawing Method

Architectured copper clad aluminium composites processed by a restacking drawing method at room temperature are reported in this work. Wires were drawn to severe plastic strain without any intermediate annealing. Three different diameters were studied in order to examine the influence of a different plastic deformation level on the structure of the different wires. Thanks to image processing it has been shown that independently of the plastic deformation, inserted fibers remain continuous and are homogeneous in size and shape. Furthermore, XRD and TEM characterizations confirm that there is no significant intermetallic growth during the deformation. Thus, the improvement and/or degradation of the functional properties of the wires can be well controlled by performing an appropriate post-processing annealing treatment. Keywords: Cu/Al composite, architectured wire, drawing, microscopy, image processing

The Mechanical Characteristics and Sealing Performance Evaluation of Bolted Pipe Flange Connections With Metallic Flat Gaskets Subjected to Internal Pressure

2016 ◽  
Author(s):  
Koji Kondo ◽  
Koji Sato ◽  
Satomi Takahashi ◽  
Toshiyuki Sawa
Keyword(s):  
Plastic Deformation ◽  
Mechanical Characteristics ◽  
Experimental Results ◽  
Leak Rate ◽  
Effect Of Temperature ◽  
Load Factor ◽  
Stress Distributions ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Higher Temperature

Bolted pipe flange connections with metallic gaskets have been used under higher pressure as well as higher temperature. However, a few researches on the mechanical characteristics in connections with metallic gaskets have been carried out. It is necessary to examine the mechanical characteristics such as the contact gasket stress distributions which govern the sealing performance, the deformation of the metallic gaskets, changes in axial bolt forces and the hub stress under higher pressure and temperature. In the present paper, the objectives are to examine the changes in axial bolt forces, the hub stress and the contact gasket stress distributions and the sealing performance of the pipe flange connections with metallic flat gaskets. Firstly, the mechanical characteristics of the connections under higher pressure are analyzed using FEA. Then, experiments were carried out to measure the load factor, the hub stress and the leak rate (the sealing performance). The relationship between the average contact gasket stress and the leak rate was measured using platen device at room temperature. The FEA results are fairly coincided with the experimental results. It is shown that the leak rate decreases as the contact gasket stress increases and when the plastic deformation of gaskets occurs, the sealing performance increases. The leak rate was measured in the range of 10−4∼10−7 [Pa·m3/s]. It is found that the sealing performance increases as the gasket width increase in the elastic deformation range while it is independent of the gasket width when the plastic deformation occurs. The effect of temperature on the mechanical characteristics of the connection is also examined. The FEA results are in a fairly good agreement with the experimental results. It is found that the sealing performance increases as the temperature increases. In addition, a method how to determine the bolt preload for increasing the sealing performance is proposed.

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