Water Absorption

Portable and manually operated chapati press cum vermicelli extruder device was designed and fabricated for the preparation of chapatis and vermicelli. Sensory evaluation overall quality scores of 50.15 and 48.4 for pressed chapatis and rolled chapatis respectively showed that quality of chapatis was not adversely affected as a result of mechanical pressing. The difference in chapati making time by manual rolling and machine pressing was 17 s per chapati and was statistically significant (p < 0.05). Combined machine produced more numbers of chapatis as machine press time per chapati was 12 s compared to 29 s of manual sheeting time. The observed variation in 1.5 mm thickness and 173.8 mm diameter from chapati to chapati was of the order of ± 0.1 mm and 1.93 mm respectively. Pressed chapati repeatability results indicated that there was no significant difference in diameters of the samples. Appearance quality characteristics scores of 8 and 7 for 2 mm and 3 mm diameter vermicelli ...

Degradation of silane coupling layers by water ingress in computer-aided design/computer-aided manufacturing (CAD/CAM) of resin composites has been reported qualitatively. In this study, we quantitatively evaluated how water absorption of CAD/CAM resin composites affects the silane coupling layer by in vitro and in silico methods. Methods: A Katana Avencia block (KAB) and an experimental matrix block composed of only a matrix resin were used to evaluate the effect of water immersion for seven days on the elastic modulus. X-ray photoelectron spectroscopy (XPS) with fluorine-labeling of the KAB was performed to evaluate the atomic percentage of F1s, which represents the hydrolysis amount by water immersion. In silico analysis of the three-dimensional model of the KAB was performed to determine the coupling ratios before and after water immersion. Results: The elastic modulus of the KAB was 8.2 GPa before and 6.9 GPa after immersion in water. The atomic percentages of F1s in the after-and before-immersion groups were 14.31% and 11.52%, respectively, suggesting that hydrolysis of the silane coupling layer occurred during water immersion. From in silico analysis of the three-dimensional model of the KAB, the coupling ratio was predicted to be 78.2% before water immersion. After water immersion, the coupling ratio was predicted to be 68.4%. Conclusion: The in vitro and in silico approaches established in this study were able to predict the silane coupling ratios of CAD/CAM resin composites, and they showed that the silane coupling ratio decreased by water absorption.

The analysis of the mineralogical composition of most rock wastes shows the presence of a high percentage of minerals with SiO2 and Al2O3, which could be used as raw materials for ceramic products. The main objective of this work is to recover wastes from one primary rock industry, utilised in the production of tiles and flooring, for the manufacturing of ceramics, using powder technology: pressing and sintering. The sinterability of the powders, with and without previous heat treatment, was studied in order to obtain a product with the best performance. Powders from different quarries after being uniaxial pressed at 40 MPa, or isostatic pressed at 170 MPa and sintered within the range 1150–1170°C present properties as follows: (a) hardness: 5.5–7.5 GPa; (b) transverse rupture strength: 55–94 MPa; (c) abrasion and erosion wear better than that of bulk to be drawn materials, and (d) water absorption of less than 0.5%. The results allow the conclusion that these wastes can be recovered and used successfully in the manufacture of ceramics with better performance than traditional tiles and flooring.

Fly ash is generated in large measures, especially by thermal power plants. A great batch of inquiry has been channeled out for efficient utilization of fly ash in the structure industry. Use of fly ash in manufacturing brick is one such thing which is being studied by many research scholars and engineers. The aim of the present study is to investigate the durability and water absorption features of fly ash bricks made up with different percentage of lime (L), local soil (S) and fly ash (FA). The experiments were conducted by both Pressure molded fly ash bricks. It was found that none of the L-S-FA bricks satisfy all the demands of standard codes. While some of the bricks satisfy the provisions in respect of intensity level only the L-S-FA (40-0- 60) bricks satisfy the demand of Indian Standard Code in respect of intensity as easily as water absorption features.

Fick’s model together with Arrhenius relationship were successfully used to evaluate water absorption of chickpea during soaking at a temperature range of 20–97 °C with 25 kHz 100 W, 40 kHz 100 W and 25 kHz 300 W ultrasound treatments. Use of ultrasound, increase in ultrasound power and soaking temperature significantly (P < 0.05) increased the water diffusion coefficient (Deff) of chickpea during soaking. Average gelatinization temperature of chickpea was found as 61.47 °C. Activation energy (Ea) values of chickpea for below and above gelatinization temperature were found to be 28.69 and 9.34 kJ mol−1, respectively. Ultrasound treatments significantly decreased the soaking time of chickpea.

An experimental investigation on the quality improvement of oil palm shell (OPS) as a coarse aggregate in lightweight concrete was conducted using several pre-treatment methods, and the pre-treated OPS aggregates were exposed to severe alkaline, acidic and strong sulphate solutions. Tests conducted on the OPS aggregates were water absorption and aggregate impact value, and tests conducted on OPS concrete were the slump, demoulded density and compressive strength. The PVA solution showed the best performance in quality improvement of OPS aggregate as well as OPS concrete among other pre-treatment methods.

Natural and wood fibre reinforced plastics as a relatively new group of environmental friendly materials have been extensively applied in interior, building applications and in the automobile industry. Among others, natural and wood fibre reinforced foamed polymer materials are of high significance because of the possibility of their reducing the density of automotive components which have a cellular structure. However, the properties of these materials have not been fully investigated and described. Microcellular composites of polypropylene containing natural and wood fibre was prepared using an injection moulding process. In the present work, the manufacturing technology of natural and wood fibre reinforced polymer microfoams was developed and the influence of fibre and microvoid content on its property spectrum was systematically investigated. The forming of microvoids and the degree of foaming related to the variation of the processing parameters in connection with manufacture technology was characterised. Measurement of density, cell size, tensile and flexural properties of the prepared composites was carried out. The cell structure is dependent on flow direction of foaming. The density of microfoamed wood fibre-PP composites was reduced by about 24% and decreased by as much as 0.77 g/cm3.Light microscopy showed that the cells are circular and it was also observed that the maximum cell sizes are between 10–50 μm. Water absorption and scanning electron microscopy of the composites were also investigated. Considering the experimental results, it can be deduced that the microcellular composites exhibit a possible combination of relatively good engineering properties and lower density for different technical applications. Natur- und holzfaserverstärkte Kunststoffe, als relativ neue Gruppe von umweltfreundlichen Werkstoffen, werden derzeit in beachtlichem Umfang in der Bauindustrie (Dach-, Boden- und Wändeabdeckungen) und Automobilindustrie verwendet. Ausserdem haben natur- und holzfaserverstärkte Polymerwerkstoffe –Mikroschäume, die wegen ihrer zellularen Struktur die Dichte der Bauteile noch reduzieren können, eine immer größere Bedeutung erlangt. Bisher sind die Eigenschaften dieser Werkstoffe nur beschränkt untersucht und beschrieben worden. Natur- und holzfaserverstärkte PP-Mikroschäume wurden im Spritzgießverfahren hergestellt. Im Rahmen der vorliegenden Arbeit wurde die Fertigungstechnik der natur- und holzfaserverstärkten Polymere-Mikroschäume entwickelt und systematisch der Einfluss des Faser-/ und Mikroporengehalts auf das Eigenschaftsspektrum dieser Werkstoffe untersucht. Mikroporen und Schäumungsgrad in Abhängigkeit von der Variation der Verarbeitungsparameter wurden in Verbindung mit dem Herstellungsprozess charakterisiert. Die Dichte, die Zellgröße, die Zug- und Biegeparameter der hergestellten Compositen wurden ermittelt. Die Schaumstruktur ist vom Fließweg abhängig. Die Dichte von geschäumten holzfaserverstärkten PP kann bis ca. 24% reduziert werden und erreicht Werte von 0,77 g/cm3. Die mikroskopischen Aufnahmen zeigen, dass die Mikroporen eine runde Struktur aufweisen, und der Porendurchmesser zwichen 10–50 μm liegt. Die Wasseraufnahme wurde ebenfalls untersucht. Die erzielten Ergebnisse belegen, dass diese Werkstoffe für verschidene Anwendungen in der Technik geeignet sind.

India is a major rice producing country, and the husk generated during milling is mostly used as a fuel in the boilers for processing paddy, producing energy through direct combustion and / or by gasification. About 20 million tones of Rice Husk Ash (RHA) is produced annually. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped. Lots of ways are being thought of for disposing them by making commercial use of this RHA. RHA can be used as a replacement for concrete (15 to 25%).This paper evaluates how different contents of Rice Husk Ash added to concrete may influence its physical and mechanical properties. Sample Cubes were tested with different percentage of RHA and different w/c ratio, replacing in mass the cement. Properties like Compressive strength, Water absorption and Slump retention were evaluated.

Introduction – Zinc is an essential micronutrient for plants, animals and humans; on the other hand, it is a pollutant. Zinc is released into the aquatic environment through several industrial activities, such as mining, metal coating, battery production and also ceramic, wood, fabric, drug, sun blocks and deodorant industry. Human exposure to these heavy metals at significant levels can cause serious health effects. Accumulated zinc at human body can lead to health problems as " metal-fume fever " , nausea, diarrhoea, depression, lethargy, and neurological signs, such asseizures and ataxia [1–3]. Consequently, removal of zinc from wastewater is necessary to ensure adequately treated effluent quality for various uses. The permissible ion concentration level in drinking water as set by World Health Organization (WHO) is 5 mg/L for zinc. In this study, perlite and chitosan dispersed perlite were used as the adsorbent. Perlite is a naturally occurring dense glassy volcanic rock which includes mainly fused sodium potassium aluminium silicate (greater than 70%) and 3–5% water. Silanol groups can form on the perlite surface providing various adsorption properties. Chitosan, poly(D-glucosamine), is obtained by deacetylation of chitin. Chitosan is a natural biopolymer, hydrophilic, and has the ability to form complexes with metals. It is also a non-toxic, biodegradable and biocompatible material. It contains primary amino groups, which are useful for chemical modifications [4]. In this study, batch studies were performed to investigate the effects of various experimental parameters on zinc removal such as pH, initial zinc concentration, contact time, adsorbent ratio. Equilibrium isotherms of batch system were also analyzed by Langmuir, Freundlich, Temkin and Dubinin-Redushkevich isotherm models. 2. Experimental-In this study, chitosan was dispersed on perlite to enhance the accessibility of OH and amine groups for adsorption of zinc ions. Chitosan coated perlite was prepared as spherical beads. Batch studies were performed to investigate the effects of various experimental parameters on zinc removal. From 0.5g/L to 12.5 g/L perlit and chitosan dispersed perlite were used as adsorbent to find the optimum zinc removal. Contact time experiments were run between 3-72 h. pH experiments were run between pH 4-10. To obtain the adsorption isotherms, initial zinc solution concentration was changed between 0.005-0.04 M. Zinc concentrations were measured by spectrophotometer (Jenway 6305 UV Spectrophotometer) according to zincon method. 3. Results and Discussion – Adsorption capacity of perlite was found %54 according to zincon method. 72 h end-over-end shaking was enough to reach the adsorption equilibrium. The maximum zinc adsorption was occurred at pH 7.5-8.0. Whereas with chitosan dispersed perlite, zinc was adsorbed at the range of %78 and zinc adsorption with chitosan dispersed perlite was reached maximum at pH =5.5-6. Zinc adsorption isotherm was obtained by changing the initial zinc concentration. Temkin isotherm model was fitted well with experimental parameters for both of the adsorbents. Maximum zinc uptake was found 1197 mg/L and 1941 mg/L for perlite and chitosan dispersed perlite, respectively. 4. Conclusions – Maximum zinc removal was observed in the presence of chitosan dispersed perlite. Temkin isotherm model described well zinc removal on the both perlite and chitosan dispersed perlite single layer zinc adsorption. Chitosan coated perlite was showed higher zinc adsorption compared with perlite.

This study investigates the feasibility of using recycled high density polyethylene (rHDPE), polypropylene (rPP) and old newspaper (rONP) fiber to manufacture experimental composite panels. The panels were made through air-forming and hot press. The effects of the fiber and coupling agent concentration on tensile, flexural, internal bond properties and water absorption and thickness swelling of wood–fiber plastic composites were studied. The use of maleated polypropylene as coupling agent improved the compatibility between the fiber and both plastic matrices and mechanical properties of the resultant composites compared well with those of non-coupled ones. Based on the findings in this work, it appears that recycled materials can be used to manufacture value-added panels without having any significant adverse influence on board properties. It was also found that composites with rHDPE provided moderately superior properties, compared with rPP samples.

We present new remote sensing indices of plant water status: the ratio between the reflectance at 970 nm, one of the water absorption bands, and the reflectance at a reference wavelength, 900 nm (R970/R9000; the first derivative minimum in this near-infrared region (dNIRminimum) and the wavelength where this minimum is found ( λNIRminimum). In order to evaluate them, we carried out three experiments. Daily irrigated gerbera plants were allowed to dry until almost wilting and then daily irrigation was restarted; pepper and bean plants were grown for four months submitted to two different irrigation treatments; and bean detached leaves were submitted to progressive dehydration whereas pressure-volume curves were being carried out.In gerbera plants, the trough about 950–970 nm decreased as the drought was increasing. Therefore, the R970/R900 index and the dNIRminimum closely tracked the changes in relative water content (RWC), leaf water potential, stomatal conductance and the foliage-air temperature differences. The λdNIRminimum tracked even better these changes in gerberas. However, these water status indices began to be significant when the water stress was already well developed, at RWC smaller than 85 per cent. The same happened to detached leaves of beans which did not present differences above −1·55 MPa water potential. Beans and peppers growing at soil matric potentials larger than −0·04 MPa presented higher R970/R900 values than those growing at soil matric potentials only larger than −0·01 MPa.In all the cases, the maximum response of these indices was found in the varieties or the species that lost cell wall elasticity in response to drought stress. This could indicate an important structural component in these indices changes. Relative water content itself seemed to be, however, the most important factor as shown by the highest correlation coefficients with these spectral indices. These spectral signals were more evident at canopy level than at leaf level. They seem to be useful as water status indicators at ground level, especially when there are not important changes of LAI and when plants wholly cover the soil.

The use of 2 wt% sugars as co-plasticizer in combination with glycerol was investigated for thermoplastic starch (TPS) from cassava. The results were compared to those for whole cassava root TPS, which naturally contains sugars in the same proportion. The main objective was to investigate the influence of natural sugars present in the cassava root on the properties of thermoplastic starch produced with cassava root. TPS produced with sugar and water without the addition of glycerol was also investigated. The materials were prepared by melt-processing cassava starch or ground and dried cassava root in a high-power batch mixer, Haake Rheomix 600, at 120 °C. The samples were tested by X-ray diffraction (XRD), dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM) and water absorption experiments. The results showed that the addition of 2 wt% sugars (glucose, fructose and sucrose) to the starch-glycerol systems causes a reduction in the glass transition temperature (Tg) of the TPS accompanied by a reduction in the storage modulus determined by DMTA and inhibits the formation of VH-type crystal structures in the resulting TPS. The use of only sugar and water as plasticizers in the TPS causes a considerable reduction (∼60%) in the subsequent water uptake.

Leaf rust, caused by Puccinia triticina, is considered one of the most important diseases of wheat. In South Africa the genes Lr29, Lr34, Lr35 and Lr37 confer effective resistance to leaf rust, qualifying them for use in cultivar improvement. To study possible secondary effects of these genes, a collection of BC6 lines containing each of the genes singly, was evaluated

A targeted experimental program was carried out to establish basic reference physical and mechanical properties of commercially available pre-cast marble chip terrazzo tiles and to investigate the effects of varying manufacturing process parameters on those properties. The transverse strength, density, water absorption, and abrasion resistance were measured as a function of casting pressure and residence time in the casting mold for a standard mix design. A simple surface abrasion index test was developed and applied comparing pre-cast terrazzo tiles with reference natural tiling stones. Recommendations for improving existing specifications and developing quality control measures are presented.