scholarly journals Preparation of xanthan gum-based composite hydrogels with aligned porous structure

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5627-5640
Author(s):  
Heli Cheng ◽  
Xu Zhang ◽  
Jiawei Xu ◽  
Sicheng Liu
Keyword(s):  
Compressive Strength ◽  
Porous Structure ◽  
Body Fluid ◽  
Sodium Acetate ◽  
Xanthan Gum ◽  
Absorption Capacity ◽  
Compressive Modulus ◽  
Cytotoxicity Test ◽  
Electron Microscope Analysis ◽  
Favorable Structure

Aligned hydrogels have received increasing attention in tissue engineering and electrochemical fields due to their favorable structure. In this work, xanthan gum-based hydrogels (XGH) with aligned pores were prepared via photoinitiated free radical irradiation that used sodium acetate crystals as template. The microstructure, compressive strength, porosity, and absorption capacity of the hydrogel were studied and compared with the non-aligned hydrogels. Scanning electron microscope analysis confirmed the aligned porous structure of the hydrogel. The maximum compressive strength for the aligned hydrogel prepared with 12% acrylamide and 1.5% xanthan gum reached 0.439 MPa at a strain of 95%. Furthermore, aligned XGH exhibited better flexibility than non-aligned hydrogels, as indicated by the Young’s compressive modulus. The porosity of the aligned hydrogels ranged from 94.9% to 88.8% as the acrylamide concentration increased from 12% to 20%. Simulated body fluid absorption showed that hydrogels with aligned pores could attain absorption equilibrium within 5 min, and the maximum absorption capacity reached 33.6 g/g for the sample made with 0.5% xanthan gum and 12% acrylamide. In addition, exhibited preferable biocompatibility, as demonstrated by the cytotoxicity test.

Pemanfaatan Limbah Padat Abu Cangkang dan Serat Kelapa Sawit dari Boiler untuk Pembuatan Bata Beton Ringan

2016 ◽  
Vol 9 (2) ◽  
pp. 120-128
Author(s):  
Haspiadi Haspiadi ◽  
Kurniawaty Kurniawaty
Keyword(s):  
Compressive Strength ◽  
Solid Waste ◽  
Palm Oil ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Palm Oil Fuel Ash ◽  
Foaming Agent ◽  
Fuel Ash ◽  
Palm Oil Mill ◽  
Oil Fuel

Research of  the utilization solid waste of palm oil fuel ash from boiler as row materials  for manufacturing light concrete brick has been conducted. The main objective of this study is to investigate the potential use solid waste of palm oil fuel ash from palm oil mill boilers as row materials for manufacturing light concrete brick has recently attracted for an alternative environmentally sustainable application. In this study, light concrete brick made with various proportions of palm oil fuel ash from palm oil mill boilers and sand were fabricated and studied under laboratory scales. Percentage of palm oil fuel ash of 0% as a control,  10%, 20%, 30%, 40%, 50%, 60%, replacement  sand, wheras others materials such as Portland cement, lime, gypsum, foaming agent and aluminium with the numbers constant. The quality of light concreate brick   were applied followed by the compressive strength test, density and water absorption capacity. The study discovered that the compressive strength for all composition meet the recommended value to light structural of 6.89 MPa as prescribed in SNI 03-3449-2002. In the same manner density of light concrete brick for all proportion under the maximum density recommended value of 1400 Kg/m3 according to SNI 03-3449-2002. While water absorption capacity of increased by the increasing use of ashes. Therefore, palm oil fuel ash from boiler can be used as raw material for the light concrete brick which is  environmental friendly because using solid waste and also an alternative handling solid waste.ABSTRAKPenelitian pemanfaatan limbah padat abu cangkang dan serat kelapa sawit dari boiler sebagai bahan baku pembuatan bata beton ringan telah dilakukan. Tujuan dari penelitian ini adalah pemanfaatan limbah padat abu boiler berbahan bakar cangkang dan serat sebagai bahan pembuatan bata beton ringan sebagai salah satu alternatif pengelolaan lingkungan yang bekelanjutan. Dalam penelitian ini, bata beton ringan dibuat dengan berbagai komposisi abu boiler dan pasir yang diproduksi dalam  skala laboratorium. Persentase dari abu berturut-turut 0% sebagai kontrol, 10%, 20%, 30%, 40%, 50% dan 60% mensubtitusi pasir, sedangkan bahan lain yaitu semen, kapur, gypsum,  foaming  agent serta aluminium pasta dengan jumlah tetap. Mutu bata beton ringan yang diujikan adalah kuat tekan, bobot jenis dan daya serap air. Hasil penelitian menunjukkan bahwa kuat tekan untuk semua komposisi memenuhi batas minimum yang dipersyaratkan untuk stuktural ringan yaitu 6,89 MPa sesuai SNI 03-3449-2002. Demikian pula bobot jenis dari bata ringan yang dihasilkan masih dibawah dari batas maksimum yang direkomendasikan SNI 03-3449-2002 yaitu maksimal 1400 Kg/m3. Sedangkan daya serap air mengalami kenaikan dengan naiknya jumlah abu yang digunakan . Limbah padat abu boiler berbahan bakar cangkang dan serat sawit dapat dimanfaatkan sebagai bahan baku pembuatan bata beton ringan yang ramah lingkungan dengan memanfaatkan limbah dan menjadi salah satu alternatif pengelolaan limbah. Kata kunci :  Abu cangkang kelapa sawit,  bata beton ringan, bobot jenis,  daya serap air,  limbah,  kuat tekan

scholarly journals Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 249
Author(s):  
Przemysław Rumianek ◽  
Tomasz Dobosz ◽  
Radosław Nowak ◽  
Piotr Dziewit ◽  
Andrzej Aromiński
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Energy Absorption ◽  
Experimental Tests ◽  
Absorption Capacity ◽  
Strain Rates ◽  
Foam Density ◽  
Energy Absorption Capacity ◽  
Closed Cell

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

scholarly journals Experimental Study on Improvement of Marine Soft Soil with Alkali Residue

2018 ◽  
Vol 53 ◽  
pp. 04021
Author(s):  
SHAO Yong ◽  
LIU Xiao-li ◽  
ZHU Jin-jun
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Void Ratio ◽  
Soft Soil ◽  
Compressive Modulus ◽  
Engineering Properties ◽  
Test Results ◽  
Use Of Resources ◽  
One Year

Industrial alkali slag is the discharge waste in the process of alkali production. About one million tons of alkali slag is discharged in China in one year. It is a burden on the environment, whether it is directly stacked or discharged into the sea. If we can realize the use of resources, it is a multi-pronged move, so alkali slag is used to improve solidified marine soft soil in this paper. The test results show that the alkali residue can effectively improve the engineering properties of marine soft soil. Among them, the unconfined compressive strength and compressive modulus are increased by about 10 times, and the void ratio and plasticity index can all reach the level of general clay. It shows that alkali slag has the potential to improve marine soft soil and can be popularized in engineering.

Study on the Aging Rules of Rigid Polyurethane Foams at Indoor Storage and Different Hygrothermal Conditions

2005 ◽  
Vol 24 (4) ◽  
pp. 197-208 ◽  
Author(s):  
Yuan-Jun Liu ◽  
Wen Zhai ◽  
Chuan-Lan He ◽  
Jian-Guo Deng ◽  
Ke-Jian Ji ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Aging Time ◽  
Fire Retardant ◽  
Ester Group ◽  
Polyurethane Foams ◽  
Compressive Modulus ◽  
Glass Beads ◽  
Hygrothermal Aging ◽  
Aging Properties ◽  
Mass Dimension

The aging rules of rigid polyurethane foam (PUR) at indoor storage and different hygrothermal conditions have been studied. Four parameters, which are mass, dimension, compressive strength and compressive modulus were tested. At indoor storage, mass, dimension and compressive strength vary slowly with an increase in aging time, while compressive modulus decreases quickly. PUR is sensitive to relative humidity (RH) verified by accelerated hygrothermal aging, and hydrolysis of ester group is the main reason resulting in the decrease of compressive properties. The filling with fire retardant and glass beads had some effect on hygrothermal aging properties of PUR. The addition of fire retardant increased compressive strength with aging time in the total trend, but it made dimension stability worse. The addition of glass beads slightly improved hygrothermal aging properties.

Effect of micro in-plane fiber waviness on compressive properties of unidirectional fabric composites

2017 ◽  
Vol 52 (15) ◽  
pp. 2065-2074 ◽  
Author(s):  
Bo Wang ◽  
Nobuhide Uda ◽  
Kousei Ono ◽  
Hiroto Nagai
Keyword(s):  
Compressive Strength ◽  
Numerical Model ◽  
Tensile Stress ◽  
Compressive Modulus ◽  
Two Dimensional ◽  
Compressive Properties ◽  
Fiber Waviness ◽  
Experimental Part ◽  
Fabric Composites ◽  
Vartm Process

In this paper, a combination of experimentation and analysis is used to study the effect of micro in-plane fiber waviness on the compressive properties of unidirectional fabric composites. The experimental part includes a measurement of the micro in-plane fiber waviness in two types of unidirectional fabrics, manufacturing composites with each unidirectional fabric via VaRTM process and tests for establishing the compressive modulus and strengths of the composites. The compressive strengths were confirmed to be affected by the micro in-plane fiber waviness, but the compressive modulus was not. Furthermore, a two-dimensional numerical model is proposed to explain our experimental results. The numerical results indicate that the tensile stress (owing to the micro in-plane fiber waviness) and compressive stress along the weft and warp directions, respectively, of the composite lead to reductions in the compressive strength.

USE OF THE MICROWAVE ENERGY FOR ALUMINUM WASTE FOAMING

2019 ◽  
Vol 25 (4) ◽  
pp. 43-49
Author(s):  
LUCIAN PAUNESCU ◽  
MARIUS FLORIN DRAGOESCU ◽  
SORIN MIRCEA AXINTE ◽  
ANA CASANDRA SEBE
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Porous Structure ◽  
Powder Mixture ◽  
Aluminum Foam ◽  
Fine Powder ◽  
Microwave Energy ◽  
Raw Material ◽  
Foaming Agent ◽  
Foaming Process

The paper presents an aluminum foam experimental technique using the microwave energy. The raw material was recycling aluminum waste processed by ecological melting and gas atomizing to obtain the fine powder required in the foaming process. The powder mixture was completed with dolomite as a foaming agent. The products had a fine and homogeneous porous structure (pore size between 0.4-0.9 mm). The density (1.17-1.19 g/cm3), the compressive strength (6.83-7.01 MPa) and the thermal conductivity (5.71-5.84 W/m·K) had values almost similar to the foams made by conventional methods.

scholarly journals CERAMIC WASTE REUSABILITY: EFFECT OF AGGREGATE GRAIN SIZE AND MIX RATIO ON LIGHTWEIGHT DENSE MASONRY UNIT PRODUCTION

2019 ◽  
pp. 3-12
Author(s):  
Ademola Ayodeji Ajayi-Banji ◽  
D. A. Jenyo ◽  
Jubril Bello ◽  
M. A. Adegbile
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Management Practices ◽  
Absorption Capacity ◽  
Ceramic Ware ◽  
Fine Aggregate ◽  
Particle Sizes ◽  
Masonry Unit ◽  
Water Absorbability ◽  
Masonry Units

Ceramic ware waste generation is becoming a global concern because of the increasing volume, hazardous nature, limited reusability, and poor waste management practices. This study examined the feasibility and efficacy of the inclusion of this waste as complementary aggregate in solid masonry unit production with bias interest on the compressive strength and water absorbability. Three particle sizes (1.4, 1.7, and 2.0 mm) of crushed ceramic ware waste were blended with natural fine aggregate under three different mix ratios (10, 20, and 30%) to produce the masonry units cured for 7, 14, 21, and 28 days prior to compressive tests analysis. Afterwards, some of the categories cured for 28-days were subjected to water absorption test. Morphology and elemental composition of the aggregates were also inspected using SEM-EDM machine. Also investigated were some of the aggregates’ physical properties. Results indicated that most of the waste-modified solid masonry units not only had water absorption capacity within required standard. The values were equally lower than the unmodified dense block (control) by 27 - 50%. Of the eighteen different categories produced, all M20T14, M20T21, and M30T28 modified dense masonry unit series with P1.7 (1.7 mm) and P2.0 (2.0 mm) particle sizes had high crushing force, compressive strength, and modulus range, which were 57 - 70 kN, 57 - 61 kN, 59 - 76 kN; 5.1 - 5.2 MPa, 5.1 - 5.5 MPa, 5.3 – 6.8 MPa; and 400 – 441 MPa, 411 – 419 MPa, 468 – 480 MPa respectively. Hence, modified masonry units with particle sizes P1.7 and P2.0 under the M20T14, M20T21, and M30T28 series are suitable masonry units for non-loading construction purposes. Interestingly, modified masonry unit (M30P2.0T7) cured under 7 days could also fit into this category. Hence, utilization of ceramic ware waste as co-aggregate in dense masonry units with M20 and M30 series production were established in this study for non-loading construction purposes

scholarly journals Bio-based rigid polyurethane foam prepared from apricot stone shell-based polyol for thermal insulation application – Part 2: Morphological, mechanical, and thermal properties

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6080-6094
Author(s):  
Muhammed Said Fidan ◽  
Murat Ertaş
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Polyurethane Foam ◽  
Flame Retardants ◽  
Compressive Modulus ◽  
Cell Diameter ◽  
Mechanical And Thermal Properties ◽  
Rigid Polyurethane Foam

The procedure for the liquefaction of apricot stone shells was reported in Part 1. Part 2 of this work determines the morphological, mechanical, and thermal properties of the bio-based rigid polyurethane foam composites (RPUFc). In this study, the thermal conductivity, compressive strength, compressive modulus, thermogravimetric analysis, flammability tests (horizontal burning and limited oxygen index (LOI)) in the flame retardants), and scanning electron microscope (SEM) (cell diameter in the SEM) tests of the RPUFc were performed and compared with control samples. The results showed the thermal conductivity (0.0342 to 0.0362 mW/mK), compressive strength (10.5 to 14.9 kPa), compressive modulus (179.9 to 180.3 kPa), decomposition and residue in the thermogravimetric analysis (230 to 491 °C, 15.31 to 21.61%), UL-94 and LOI in the flame retardants (539.5 to 591.1 mm/min, 17.8 to 18.5%), and cell diameter in the SEM (50.6 to 347.5 μm) of RPUFc attained from liquefied biomass. The results were similar to those of foams obtained from industrial RPUFs, and demonstrated that bio-based RPUFc obtained from liquefied apricot stone shells could be used as a reinforcement filler in the preparation of RPUFs, specifically in construction and insulation materials. Moreover, liquefied apricot stone shell products have potential to be fabricated into rigid polyurethane foam composites.

scholarly journals OPTIMUM PERFORMANCE OF STABILIZED EDE LATERITE AS AN ALTERNATIVE CONSTRUCTION MATERIAL

2020 ◽  
Vol 3 (8) ◽  
pp. 1-8
Author(s):  
Adegbenle Bukunmi O
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Construction Material ◽  
High Water ◽  
Good Alternative ◽  
Linear Shrinkage ◽  
Absorption Capacity ◽  
Water Absorption Capacity ◽  
Optimum Performance ◽  
High Water Absorption

Laterite samples from Ede area with particle components of 19.7% clay, 32.8% silt and 47.5% sand was stabilized with combined cement, lime and bitumen and test for Compressive strength, Linear Shrinkage, Permeability and Water Absorption. The stabilizers were mixed with laterite soil in different ratios and percentage. The laterite carried 90% which is constant while the three stabilizers shared the remaining 10% in varying form. After 28 days of curing, laterite stabilizer with 90% of laterite, 8% of cement, 1% lime and 1% bitumen (LCLB1) possessed compressive strength of 2.01N/mm2. It Water Absorption Capacity was 3.05%. LCLB4 stabilizer (90% laterite, 6% cement, 2% lime and 2% bitumen) has the same compressive strength with LCLB1 stabilizer but with a high Water Absorption Capacity of 4.2%. The stabilizer of 90% laterite, 3.33% cement, 3.33% lime and 3.33% of bitumen (LCLB8) has the lowest compressive strength of 0.74N/mm2 and the highest Water Absorption Capacity of 5.39%. The results shows that LCLB1 stabilizer is a better stabilizer for strength and blocks made from laterite stabilized with it stand a good alternative to sand Crete blocks in building constructions. The combination of these stabilizers in order to determine a most economical volume combination for optimum performance is highly possible and economical.

Behaviour of Calcium Alkali Orthophosphate Cements under Simulated Implantation Conditions

2008 ◽  
Vol 396-398 ◽  
pp. 213-216 ◽  
Author(s):  
Daniela Jörn ◽  
Renate Gildenhaar ◽  
Georg Berger ◽  
Michael Stiller ◽  
Christine Knabe
Keyword(s):  
Compressive Strength ◽  
Simulated Body Fluid ◽  
Clinical Application ◽  
Body Fluid ◽  
Setting Time ◽  
Great Decrease ◽  
Final Setting Time ◽  
Laboratory Conditions ◽  
Setting Times

The setting behaviour, the compressive strength and the porosity of four calcium alkali orthophosphate cements were examined under laboratory conditions (dry) and under conditions similar to those during clinical application (37°C, contact with body fluid). The results showed an increase of the setting times when specimens were covered with simulated body fluid. Especially, the final setting time (FHZ) was significantly higher for three of the four cements. Furthermore, when specimens were stored in SBF for 16h, an extensive decrease of the compressive strength was noted. The porosity was more than twice as high after 16h in SBF and this may be the cause for the great decrease of the compressive strength.

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