scholarly journals Test Method for the Solubility Model of Physical Blowing Agent of Self-Expanding Polymer

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Heyang Jia ◽  
Xiaolong Li ◽  
Meimei Hao ◽  
Yang Li ◽  
Yanhui Zhong ◽  
...  
Keyword(s):  
Diffusion Mechanism ◽  
Engineering Application ◽  
Mass Conservation ◽  
Test Method ◽  
Solubility Curve ◽  
Blowing Agent ◽  
Foaming Process ◽  
Complete Test ◽  
Solubility Model ◽  
Verification Process

This paper aims to present a solubility model of physical blowing agent (PBA) for a kind of commonly used self-expanding polymer on engineering. The self-expanding polymer contains Component A (isocyanate) and Component B (polyhydric alcohol, PBA, water, and catalyst). Component B grout of the polymer, which contains PBA, was heated to measure its temperature and volume variations. Based on the principle of mass conservation and Clapeyron equation, the solubility curve of PBA with respect to temperature was calculated. The solubility curve was then applied to simulate the foaming process. A two-component polymer grout foaming experiment was then carried out to verify the applicability of the measured solubility curve. The simulated changes of temperature and density with respect to time of polymer grout were analyzed and compared with experimental results. The error of both sets of curves is within 5%, which shows a good agreement among them and proves the feasibility of the solubility model. This study provides a relatively complete test and verification process for the solubility model of PBA, which lays a theoretical foundation for both the polymer grouting diffusion mechanism and engineering application.

scholarly journals Investigation of the sustained-release mechanism of hydroxypropyl methyl cellulose skeleton type Acipimox tablets

2018 ◽  
Vol 16 (1) ◽  
pp. 333-339
Author(s):  
Wanying Liu ◽  
Qing Huo ◽  
Yue Wang ◽  
Na Yu ◽  
Rongjian Shi
Keyword(s):  
Sustained Release ◽  
Diffusion Mechanism ◽  
Methyl Cellulose ◽  
Magnesium Stearate ◽  
Test Method ◽  
Release Mechanism ◽  
Hydroxypropyl Methyl Cellulose ◽  
Hypolipidemic Agents ◽  
Sustained Release Tablets ◽  
The Difference

AbstractIn this study, we investigate the production of hypolipidemic agents in the form of Acipimox sustained-release tablets, using a wet pelleting process. The purpose of this research is to reduce the total intake time for patients and to lower the initial dose in such that the adverse reactions could be reduced. This study adopts the single-factor method and orthogonal experiments by using hydroxypropyl methyl cellulose (HPMC K15M) as the main sustained-release prescription composition. The final prescription is Acipimox 20%, HPMC K15M 26.67%, sodium carboxymethyl cellulose 30%, polyethylene glycol (PEG 6000) 1%, ethyl cellulose 16.6%, lactose 4.67% and magnesium stearate 1%. The dissolution of tablets reached 85.88% in 8 h. The difference in the weight, hardness and friability of the tables met the requirements in the Chinese Pharmacopoeia; to test the stability, a temperature and illumination accelerated test method was used, the results indicate that the Acipimox sustained-release tablets should be sealed and stored in a dark, cool area. A preliminary study on the tablets’ releasing mechanism showed that their release curve fitted the Higuchi model (the formula is Mt/M∞ = 31.137 t1/2–3.605 (R2 = 0.9903)). The Acipimox tablets’ release principle is dominated by the diffusion mechanism.

The Judgment Method Based on F-Test for the Best Clustering Scheme of Self-Organizing

2011 ◽  
Vol 304 ◽  
pp. 366-370
Author(s):  
Dong Sheng Zhang ◽  
Chao Ji
Keyword(s):  
Engineering Application ◽  
Test Method ◽  
Mathematical Statistics ◽  
Theoretical Research ◽  
Self Organization ◽  
F Test ◽  
Test Analysis ◽  
Self Organizing

To avoid the optional and uncertainty when judge self-organization clustering results, we have introduced the F-test method what have used in mathematical statistics. The method calculat and compares inner-class distance and inter-class distance respectively what from various clustering schemes, and then get the best clustering scheme through the F-test analysis. The experiment results show that the method is athematically proved rigorously, program operation is stable and reliable, and with larger value both in theoretical research and engineering application.

Research on Multi-Excitation Source United Controlling Test Method Based on Distributed Actuation

2011 ◽  
Vol 291-294 ◽  
pp. 2168-2174
Author(s):  
Jun Yao ◽  
Yan Fei Wu ◽  
Ming Ge Xu
Keyword(s):  
High Speed ◽  
Engineering Application ◽  
Piezoelectric Element ◽  
Test Method ◽  
Excitation Source ◽  
Vibration Test ◽  
Test Technique ◽  
Test Items ◽  
Application Potential ◽  
Vibrating Table

In view of the questions of high-speed aircraft withstanding complicated vibration environment, their vibration durability could not being plenary examined by existing vibration test technology, a vibration test technique integrating piezoelectric element, vibrating table, exciter is proposed. The vibration environment dimension of high-speed aircraft and its influence to the failures of high-speed aircraft are analysed. Based on the research on the material and actuation dimension of the piezoelectric element, the feasibility of piezoelectric element used as the distributed excitation source in vibration test is analysed. Last, a test demonstration system is constituted and a serials of test items are carried out. The rationality and the extensive engineering application potential of this technique are verified by the test results.

The Influence of the Foaming Agents on the Porosity of the PM Hydroxyapatite-Based Biocomposites Processed by Two-Step Sintering

2015 ◽  
Vol 1128 ◽  
pp. 178-186
Author(s):  
Cristina Teișanu ◽  
Carmen Ristoscu ◽  
Gabriela Sima
Keyword(s):  
Foaming Agent ◽  
Foaming Agents ◽  
Space Holder ◽  
Blowing Agent ◽  
Foaming Process ◽  
Eds Analysis ◽  
Titanium Hydride Powder ◽  
The Matrix ◽  
Powder Particles ◽  
Hydride Powder

This paper presents a comparative analysis of the foaming process developed in hydroxyapatite (HAp)-based bicomposites as a function of the foaming agent. The matrix of the biocomposite consists of either submicronic or micronic powder particles of HAp. The titanium hydride powder was added as reinforcement’s precursor as well as blowing agent, and in order to increase the biocomposites’ porosity calcium carbonate was added as space holder agent. The powders mixture was homogenized in a planetary ball mill with a single grinding bowl for 1 minute in air. Uniaxial cold compaction at 120-170 MPa was performed in order to obtain cylindrical green parts, which next were heated in argon atmosphere using the two step sintering technique at temperatures of 900 °C for 1 minute and 800°C for 450 - 600 minutes. The porosity of the biocomposite is analysed through calculations and SEM and EDS analysis highlighting the influence of the above mentioned foaming techniques (blowing and space holder).

scholarly journals Comparative experimental research on falling ball test method and K30 plate load method on foundation of different structures

2021 ◽  
Vol 276 ◽  
pp. 02025
Author(s):  
Yingqi Xue ◽  
Xiaokun Han ◽  
Luwan Wang ◽  
Mengjie Wang
Keyword(s):  
Engineering Application ◽  
Layered Materials ◽  
Comparative Test ◽  
Test Method ◽  
Construction Process ◽  
Fine Grained ◽  
Surface Deflection ◽  
Fine Grained Material ◽  
The Relationship ◽  
Ball Test

In highway and railway foundation projects, the mechanical properties of foundation materials are one of the main indicators of construction process control. The elastic modulus of foundation directly affects road surface deflection and must be tested. The falling ball test method and the K30 plate load method are widely used in engineering, In order to explore the relationship between the two methods and guide the engineering application, the falling ball test method and the K30 plate load method are applied to homogeneous materials (homogeneous fine-grained material layers) and layered materials(Old foundation).Through comparative test, we found that there is a strong correlation between the falling ball test method the K30 plate load method in some scenarios,which can be used for mutual reference in engineering experiments.

scholarly journals Viscoelastic epoxy foams by an aqueous emulsion foaming process

2019 ◽  
Vol 56 (1) ◽  
pp. 105-118
Author(s):  
Du Ngoc Uy Lan ◽  
Muhammad Syazwan Fauzi ◽  
Cao Xuan Viet ◽  
Daniel Raps ◽  
Volker Altstädt
Keyword(s):  
Sodium Bicarbonate ◽  
High Speed ◽  
Water Molecules ◽  
Aqueous Emulsion ◽  
Blowing Agent ◽  
Compression Set ◽  
Foaming Process ◽  
A Cell ◽  
Viscoelastic Foams ◽  
Emulsifying Ability

The research proposed an aqueous emulsion foaming process to produce a viscoelastic epoxy foam having a density of 0.33–0.36 g/cm3 from the polyamide–epoxy adduct, which uses a reverse ratio of epoxy and polyamide hardener. The process is simple, economical and uses no surfactant, thanks to the emulsifying ability of polyamide hardener. Firstly, the mixture of excess polyamide, epoxy and sodium bicarbonate was emulsified with distilled water using high-speed stirring to form dispersed epoxy droplets in water. Secondly, a solution of ammonium chloride was added, which reacted with sodium bicarbonate to produce carbon dioxide and ammonia gases dispersed in the epoxy emulsion. The expanding gases induced flocculation and partial coalescence of the epoxy droplets; sequentially water molecules were entrapped within them. Finally, a curing process was carried out to stabilise the foam morphology and structure. Two types of pore morphologies were observed: a large foam-pore generated from blowing-agent gases and a cell-wall pore formed from the vapourisation of entrapped water (as the void template). Porosity and pore morphologies depended on blowing-agent content, and the viscoelasticity was affected by the epoxy/polyamide ratio. The obtained viscoelastic foams showed a large number of interconnected cells and exhibited high compression set values.

Investigation of thermoplastic elastomer (TPE) foaming process using blowing agent by rheological and morphological methods

2018 ◽  
Vol 136 (8) ◽  
pp. 47358
Author(s):  
Hyo Jae Kong ◽  
Seung Hak Lee ◽  
Dong Gun Kim ◽  
Hyo Jun Kim ◽  
Gun Wook Park ◽  
...  
Keyword(s):  
Thermoplastic Elastomer ◽  
Blowing Agent ◽  
Foaming Process

Dynamic rheology and foaming behaviour of styrene–ethylene–butylene–styrene/ polystyrene blends

2016 ◽  
Vol 53 (4) ◽  
pp. 389-406 ◽  
Author(s):  
Ritima Banerjee ◽  
Suprakas Sinha Ray ◽  
Anup K Ghosh
Keyword(s):  
Volume Expansion ◽  
Complex Viscosity ◽  
Expansion Ratio ◽  
Dynamic Rheology ◽  
Blowing Agent ◽  
Foaming Process ◽  
Lower Volume ◽  
Foaming Temperature ◽  
And Storage ◽  
Nucleating Effect

Styrene–ethylene–butylene–styrene and its blends containing 10, 30 and 50 wt% polystyrene were subjected to batch foaming using physical blowing agent carbon dioxide. At higher foaming temperatures (80–110℃), complex viscosity ( η*) and storage modulus ( E′) were found to control the volume expansion ratio and the shrinkage of foams. For a given composition, optimal volume expansion was achieved at temperatures close to the glass transition temperature ( T g) of the polystyrene phase of that composition, indicating the presence of a complex viscosity window favourable for the foaming process. Blends with 30% and 50% polystyrene content possessed higher values of E′ and η*, and produced stable foams having higher volume expansion ratio, when foamed within their respective η* windows. At a much lower foaming temperature (35℃), polystyrene was found to have a nucleating effect. However, irrespective of rheological properties, all foams showed prominent shrinkage. A higher polystyrene content resulted in a lower volume expansion ratio, as well as shrinkage over a shorter period of time and a greater extent of shrinkage in the same time span. This can be attributed to the selective foaming of the ethylene–butylene phase, hindered by the stiff polystyrene aggregates.

scholarly journals Shale Gas Productivity Predicting Model and Analysis of Influence Factors

2015 ◽  
Vol 8 (1) ◽  
pp. 203-207 ◽  
Author(s):  
Yin Daiyin ◽  
Wang Dongqi ◽  
Zhang Chengli ◽  
Duan Yingjiao
Keyword(s):  
Mathematical Model ◽  
Pressure Gradient ◽  
Shale Gas ◽  
Diffusion Mechanism ◽  
Influence Factors ◽  
Mass Conservation ◽  
Isothermal Adsorption ◽  
Start Up ◽  
Gas Seepage ◽  
The Impact

In order to find the dynamic characteristics of shale gas reservoirs and improve shale gas well production, it is very important to research on shale gas seepage mechanism and production evaluation. Based on the shale gas seepage mechanism, adsorption and desorption characteristics, the diffusion mechanism and mass conservation theory in shale gas development, the dual pore medium shale gas reservoir mathematical model is set up. The mathematical model is built by the finite difference method based on start-up pressure gradient, slippage effect and the isothermal adsorption principle, and then programmed to solve it. Finally, this paper analyzed the impact of Langmuir volume, Langmuir pressure, start-up pressure gradient and slippage coefficient and other factors on shale gas wells production.

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