Enhanced mechanical, crystallisation and thermal properties of graphene flake-filled polyurethane nanocomposites: the impact of thermal treatment on the resulting microphase-separated structure

2021 ◽  
Vol 28 (8) ◽  
Author(s):  
Muayad Albozahid ◽  
Haneen Zuhair Naji ◽  
Zoalfokkar Kareem Alobad ◽  
Alberto Saiani
Keyword(s):  
Thermal Properties ◽  
Thermal Treatment ◽  
Graphene Flake ◽  
The Impact ◽  
Polyurethane Nanocomposites

scholarly journals A multilevel investigation supported by multivariate analysis for tomato product formulation

2021 ◽  
Author(s):  
Fatma Boukid ◽  
Elena Curti ◽  
Agoura Diantom ◽  
Eleonora Carini ◽  
Elena Vittadini
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Water Molecules ◽  
Thermal Treatments ◽  
Industrial Processing ◽  
H Nmr ◽  
Mobile Populations ◽  
Product Formulation ◽  
Tomato Product ◽  
The Impact

AbstractIndustrial processing of tomato includes its cutting and mincing, thermal treatments, and the addition of ingredients, which might induce changes in physicochemical properties of the final products. In this frame, the impact of texturing/thickening [xanthan gum (X) or potato fiber (F)] on the macroscopic, mesoscopic and molecular properties of tomato double concentrate (TDC) was investigated to determine if F can efficiently substitute X, in association with small solutes (sugar and salt) and thermal treatment (cold and hot). At a macroscopic level, multivariate statistics (MANOVA) underlined that color change (ΔE) was increased by X and F addition contrary to heating and the addition of salt and sugar. MANOVA revealed that texture was greatly enhanced through the use of F over X. 1H NMR molecular mobility changes were more controlled by texturing agents (F and X) than thermal treatment and small solutes. Particularly F increased the more rigid population indicating stronger interaction with water molecules resulting in shear-thinning flow. However, adding X contributed into the increase of the dynamic and mobile populations. Therefore, F can be a valid “clean label” substitute of X in modulating tomato products properties.

The Lateral Cross-Linking of Polyurethane Using Grafted Epichlorohydrin and the Impact on the Tensile and Thermal Properties

2016 ◽  
Vol 37 (2) ◽  
pp. 323-331 ◽  
Author(s):  
Yong-Chan Chung ◽  
Byung Hee Lee ◽  
Jae Won Choi ◽  
Byoung Chul Chun
Keyword(s):  
Thermal Properties ◽  
Cross Linking ◽  
The Impact

scholarly journals Problems of Analyzing Microstructure Images in Assessing the Impact of Technological Parameters of Combined Strain Wave Hardening on the Quality of the Surface Layer

2019 ◽  
Author(s):  
Андрей Киричек ◽  
Andrey Kirichek ◽  
Дмитрий Соловьев ◽  
Dmitriy Solovyev ◽  
Александр Хандожко ◽  
...  
Keyword(s):  
Surface Layer ◽  
Thermal Treatment ◽  
Strain Wave ◽  
Technological Parameters ◽  
Steel Microstructure ◽  
Main Indicator ◽  
Metallographic Images ◽  
Surface Layer Quality ◽  
The Impact

The problems of analyzing metallographic images and the method of their solution using modern software for the analysis of metallographic images are described. There is given an analysis of microstructure images as the main indicator of the surface layer quality by the example of studying the research results of strain wave hardening combinations and chemical-thermal treatment, in particular the influence of previous strain wave hardening and subsequent thermal and chemical- thermal treatment on the alloy steel microstructure or previous thermal and chemical- thermal treatment and subsequent strain wave hardening. On the basis of the analysis the effectiveness of strain wave hardening and chemical and thermal treatment is established.

scholarly journals Influence of partial replacement of sand with copper slag on the thermal properties of hardened concrete

2019 ◽  
Author(s):  
Łukasz Majewski ◽  
Roman Jaskulski ◽  
Wojciech Kubissa
Keyword(s):  
Thermal Properties ◽  
Cement Content ◽  
Copper Slag ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Different Types ◽  
Compressive Strength Of Concrete ◽  
The Impact ◽  
Fine Copper ◽  
Slag Waste

The article presents the results of testing the effect of partial replacement of sand with fine copper slag waste on the thermal properties of hardened concrete. The impact of the replacement on mechanical properties (ie. compressive and tensile strength of concrete) was also investigated. The thermal properties of the concrete were determined using the non-stationary method with the ISOMET 2114 device. Tests were performed on concrete containing three different types of cement (CEM I, CEM II and CEM III). A total cement content of 360 kg/m3 was assumed in the compositions of all concrete mixes with a water-cement ratio of 0.45. Replacing 66% of the sand volume with copper slag waste caused a decrease in thermal conductivity by about 4–8% in relation to the reference concrete. In addition, the compressive strength of concrete containing copper slag increased by about from 4–21% in relation to the reference concrete.

Evaluating Thermal Cycling Fatigue Resistance for LED Chip-on-Board Applications

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 000706-000737
Author(s):  
Ravi M. Bhatkal ◽  
Ranjit Pandher ◽  
Anna Lifton ◽  
Paul Koep ◽  
Hafez Raeisi Fard
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Cycle ◽  
Metal Core ◽  
Creep Fatigue ◽  
Cte Mismatch ◽  
Thermal Cycling Fatigue ◽  
Transient Thermal ◽  
The Impact

LED chip-on-board applications typically involve assembling an LED die stack directly on to a high thermal conductivity substrate such as a Metal Core PCB. If solder is used for die-substrate attach for such chip-on-board applications, one needs to consider the CTE mismatch between the die stack and the MCPCB and its impact on thermal cycle-induced creep fatigue of the solder material. This paper presents a methodology to compare relative performance of different solder materials with varying thermo-mechanical properties, and compare the impact of CTE mismatch and temperature swings on transient thermal properties and relative reliability of the solder attach materials. Implications for LED chip-on-board applications are discussed.

scholarly journals Thermal Behavior of Worsted Fabrics Produced from Different Yarn Spinning Systems

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800 ◽  
Author(s):  
Abolfazl Mirdehghan ◽  
Siamak Saharkhiz ◽  
Hooshang Nosraty
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Behavior ◽  
Thermal Insulation ◽  
Weft Yarn ◽  
Spun Yarn ◽  
Finishing Process ◽  
Yarn Structure ◽  
Fabric Structures ◽  
The Impact

This paper describes an experimental study of the impact of yarn structure on the thermal properties of worsted fabric. In this study, four different spun yarn structures (Solo, Siro, and single ply and two ply Ring) were woven into four fabric structures (Plain, Twill2/1, Twill2/2 and Basket2/2) and their thermal properties were studied. In addition, the thermal behavior of finished and unfinished samples was also evaluated. Results showed that the finishing process causes an increase in thermal conductivity and warmth to weight factor and a decrease in thermal insulation. Different spinning systems, also affect the thermal properties of the worsted fabrics. Samples with Siro yarns in the weft were found to have the highest thermal conductivity and those made from single ply weft yarn the lowest thermal conductivity. A relation between fabric thermal insulation and air permeability and thickness was also found.

Effect of thermal treatment on the impact strength of polycarbonate

1986 ◽  
Vol 60 (8) ◽  
pp. 2678-2682 ◽  
Author(s):  
Lee E. Hornberger ◽  
Gloria Fan ◽  
K. L. DeVries
Keyword(s):  
Thermal Treatment ◽  
Impact Strength ◽  
The Impact

Thermal decomposition of solder flux activators under simulated wave soldering conditions

2017 ◽  
Vol 29 (3) ◽  
pp. 133-143 ◽  
Author(s):  
Kamila Piotrowska ◽  
Morten Stendahl Jellesen ◽  
Rajan Ambat
Keyword(s):  
Thermal Treatment ◽  
Heat Exposure ◽  
Copper Surface ◽  
Substrate Material ◽  
Content Type ◽  
Soldering Process ◽  
Wave Soldering ◽  
Solder Flux ◽  
Solder Mask ◽  
The Impact

Purpose The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design/methodology/approach Changes in the chemical structure of the activators were studied using Fourier transform infrared spectroscopy technique and were correlated to the exposure temperatures within the range of wave soldering process. The amount of residue left on the surface was estimated using standardized acid-base titration method as a function of temperature, time of exposure and the substrate material used. Findings The study shows that there is a possibility of anhydride-like species formation during the thermal treatment of fluxes containing weak organic acids (WOAs) as activators (succinic and DL-malic). The decomposition patterns of solder flux activators depend on their chemical nature, time of heat exposure and substrate materials. Evaporation of the residue from the surface of different materials (laminate with solder mask, copper surface or glass surface) was found to be more pronounced for succinic-based solutions at highest test temperatures than for adipic acid. Less left residue was found on the laminate surface with solder mask (∼5-20 per cent of initial amount at 350°C) and poorest acid evaporation was noted for glass substrates (∼15-90 per cent). Practical implications The findings are attributed to the chemistry of WOAs typically used as solder flux activators. The results show the importance WOA type in relation to its melting/boiling points and the impact on the residual amount of contamination left after soldering process. Originality/value The results show that the evaporation of the flux residues takes place only at significantly high temperatures and longer exposure times are needed compared to the temperature range used for the wave soldering process. The extended time of thermal treatment and careful choice of fluxing technology would ensure obtaining more climatically reliable product.

Studies on Mechanical and Thermal Properties of Epoxy Resin Modified by Fluorine-Containing Silicone

2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Bending Strength ◽  
Mechanical And Thermal Properties ◽  
Curing Agent ◽  
Epoxy System ◽  
Resin Curing ◽  
The Impact ◽  
Modified Epoxy

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.

scholarly journals Measurement of the hysteretic thermal properties of W-doped and undoped nanocrystalline powders of VO2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
C. L. Gomez-Heredia ◽  
J. A. Ramirez-Rincon ◽  
D. Bhardwaj ◽  
P. Rajasekar ◽  
I. J. Tadeo ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hysteresis Loops ◽  
Thermal Effusivity ◽  
Combustion Method ◽  
Rutile Phase ◽  
Metallic Phase ◽  
Nanocrystalline Powders ◽  
Solution Combustion ◽  
The Impact ◽  
W Doping

Abstract Hysteresis loops exhibited by the thermal properties of undoped and 0.8 at.% W-doped nanocrystalline powders of VO2 synthesized by means of the solution combustion method and compacted in pellets, are experimentally measured by photothermal radiometry. It is shown that: (i) the W doping reduces both the hysteresis loops of VO2 and its transition temperature up to 15 °C. (ii) The thermal diffusivity decreases (increases) until (after) the metallic domains become dominant in the VO2 insulating matrix, such that its variation across the metal-insulation transition is enhanced by 23.5% with W-0.8 at.% doping. By contrast, thermal conductivity (thermal effusivity) increases up to 45% (40%) as the metallic phase emerges in the VO2 structure due to the insulator-to-metal transition, and it enhances up to 11% (25%) in the insulator state when the local rutile phase is induced by the tungsten doping. (iii) The characteristic peak of the VO2 specific heat capacity is observed in both heating and cooling processes, such that the phase transition of the 0.8 at.% W-doped sample requires about 24% less thermal energy than the undoped one. (iv) The impact of the W doping on the four above-mentioned thermal properties of VO2 mainly shows up in its insulator phase, as a result of the distortion of the local lattice induced by the electrons of tungsten. W doping at 0.8 at.% thus enhances the VO2 capability to transport heat but diminishes its thermal switching efficiency.

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