Water Absorption Potential Research Articles

Selection of biological prosthesis for abdominal wall repair on the basis of in vitro biocompatibility determination.

Research on prostheses for repairing abdominal wall defects has progressed through past decades for developing an ideal prosthesis. The study was designed to compare different extracellular matrix (ECM) derived biological prostheses as alternate to conventional synthetic polymeric prostheses for the repair of full thickness abdominal wall defects. Five biological scaffolds derived from bovine diaphragm, bovine aorta, bovine gall bladder, porcine gall bladder, and rabbit skin were prepared and screened for their in vitro biocompatibility. Decellularized ECMs were subjected to various biocompatibility analyses, namely, water absorption potential, matrix degradation analysis, biomechanical testing, and cytocompatibility analysis. Though the rabbit skin displayed maximum biomechanical strength, due to its rapid degradation, it failed to fulfill the criteria of an ideal prosthesis. ECMs derived from bovine diaphragm and aorta were found to be superior than others based upon hydration and matrix degradation analysis, with best scores for bovine diaphragm followed by bovine aorta. The bovine diaphragm and aorta also displayed sufficient biomechanical strength, with diaphragm being the second highest (next to rabbit skin), in biomechanical strength followed by aorta. None of the biological prosthesis revealed any cytotoxicity. Thus, bovine diaphragm and aorta derived ECM fulfill the necessary criteria for their use as biological prosthesis. Because these prostheses are biocompatible, apart from their low cost, ease of availability, and simple preparation, they present a potential alternative to synthetic prosthesis for repair of abdominal wall defects, especially in veterinary patients.

Structural and Techno-Functional Properties of Cassava Starches and Application on Cheese Bread

This study aims to evaluate the structural and techno-functional properties of native and modified cassava starches, focusing on the production of frozen cheese bun formulations. The structural and techno-functional properties of cassava starches, both native and modified, were evaluated via thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), baking properties, as well as, resistance to freezing and thawing cycles. The native sample containing 17% of amylose had the highest expansion rate among the tested starches. In contrast, pre-gelatinized acetylated starches showed little expansion capacity. The starch samples displayed resistance to up to 2 freezing and thawing cycles. The XRD analysis showed that native and modified starches had high crystallinity and similar diffraction patterns. SEM images revealed that modified starches possess smaller particles (32 to 52 μm) with a greater surface area when compared to the native samples. Modified samples also displayed surface indentations, which would explain their greater water absorption potential. TGA analysis has shown a reduction (P<0.05) in the modified starches thermal stability. These data are relevant technological advancement of the cheese bun industry since choosing adequate starch is crucial to ensure the final product's quality in large scale industrial production.

Low-Carbon Concrete Based on Binary Biomass Ash-Silica Fume Binder to Produce Eco-Friendly Paving Blocks.

The civil construction industry consumes huge amounts of raw materials and energy, especially infrastructure. Thus, the use of eco-friendly materials is indispensable to promote sustainable development. In this context, the present work investigated low-carbon concrete to produce eco-friendly paving blocks. The binder was defined according to two approaches. In the first, a binary binder developed with eucalyptus biomass ash (EBA) and silica fume (SF) was used, in total replacement for Portland cement. In the second, the mixture of residues was used as a precursor in alkali-activation reactions, forming alkali-activated binder. The experimental approach was carried out using five different mixtures, obtained by varying the amount of water or sodium hydroxide solution. The characterization of this new material was carried out using compressive strength, expandability, water absorption, deep abrasion, microstructural investigation, and organic matter degradation potential. The results showed that the EBA-SF system has a performance compatible with Portland cement when used as an alternative binder, in addition to functioning as a precursor to alkali-activated concrete. The blocks produced degraded organic matter, and this degradation is more intense with the incidence of UV. In this way, the EBA-SF binder can be successfully used for the manufacture of ecological paving blocks with low carbon emissions.

Physically cross-linked aerogels based on germinated and non-germinated wheat starch and PEO for application as water absorbers for food packaging

The objective of this study was to generate and characterize physically cross-linked aerogels by using germinated and non-germinated wheat starch, with and without the addition of poly (ethylene oxide) (PEO). Aerogels were produced by gelatinization of starch (10% w/v, in distilled water) at 90 °C, followed by multiple freeze/thaw cycles. For the aerogel produced using starch and PEO, a solution of 6% PEO (0.6 g of PEO/10 mL of distilled water) was added to the dispersion. The thermal properties, infrared spectra, relative crystallinity, morphology, water absorption properties, and texture profile of the aerogels were evaluated. After immersion in water for 24 h, the aerogels exhibited high degradation temperature, water absorption capacity, and physical integrity. Aerogels produced using the germinated wheat starch were much more integrated structurally compared to the aerogels produced using the non-germinated wheat starch. Wheat germination did not have any impact on the textural parameters of the aerogels. However, addition of PEO increased the water absorption capacity and reduced the hardness and cohesion of the resulting aerogels. Due to the high water absorption potential, the aerogel produced in this study can serve as an absorbent matrix in food packaging.

Moisture tension in fine-grained reconstituted soils at high initial water contents

The reclamation of land filled with high water content dredged clays is an important geological and geo-environmental issue. When designing such reclaimed land, the yield behaviour during compression is of paramount importance because it conditions the compressibility of soil and thus the final ground settlement. Previous studies suggest a significant effect of initial state of soils on their compression behaviour; in particular, the remoulded yield stress (identified when compressing reconstituted samples at high initial water content) decreased with the increase in initial water content. This phenomenon has been attributed to the effect of moisture tension. In fact, for a reconstituted soil at high initial water content, non-destroyed aggregates may exist in microscopic level although the degree of saturation of soil reaches 100% in macroscopic level. These aggregates can give rise to the generation of negative water pressure inside the aggregates, namely moisture tension. This moisture tension can greatly affect the mechanical behaviour of soil in the macroscopic level. With the destruction of aggregates, the moisture tension decreases. In order to verify this surmise, a series of experiments were conducted with moisture tension measurement on reconstituted Jossigny silt at three different water contents (1.0, 1.2 and 1.5 times the liquid limit). Meanwhile, mercury intrusion porosimetry (MIP) tests were conducted to analyse the macroscopic features. The test results proved the existence of moisture tension, and it decreased with increasing water content. When the aggregates are destructed completely, the moisture tension becomes zero. The non-intruded void ratio obtained from MIP tests was found to increase with decreasing water content, suggesting the destruction of aggregates by further hydration. Physically, the moisture tension corresponds to the water absorption potential of aggregates or the potential changes of aggregates from metastable state to true stable state. These observations provide experimental evidence supporting the existence of the remoulded yield stress identified for saturated reconstituted soils.

Durability characteristics of lightweight rubberized concrete

This study experimentally investigates the durability characteristics of rubberized concrete up to 30% rubber content. The durability characteristics including the carbonation depth, standard potential, water absorption, and initial rate of absorption of rubberized concrete were investigated. The experimental results have shown that rubberized concrete absorbed more water than conventional concrete, and the water absorption increased with the rubber content. Therefore, rubberized concrete is more susceptible to water, chloride, and chemical attacks. The carbonation depth of rubberized concrete was also higher than that of the conventional concrete and it increased with the rubber contents, indicating more susceptibility to corrosion. Although the estimated service life of rubberized concrete is shorter than that of conventional concrete, with 15% rubber contents it exceeds 50 years according to fib CEB-FIP [1] and AS 3600 [2]. Rubberized concrete thus can be used for structural components with sufficient strength and adequate service life up to 15% rubber content. In addition, the pre-treatment methods with NaOH or water were found to have considerable effects on carbonation depth but marginal effects on the water absorption and standard potential of rubberized concrete.

Proposing a new approach to the selection of material portfolio using a combination of data mining and optimisation methods

The present paper aims to provide a new framework for the selection of a portfolio of materials. This paper shows that, compared with the traditional methods in the selection of materials, how the new materials are analysed based on new ideas. The case study is materials required for production of tile glaze in both traditional and modern methods. Modelling in this study was done based on mathematical description approach. The results of execution of feature selection algorithm revealed that important factors in the selection of glaze for production of tile in both traditional and modern methods include cracking, self-cleaning, uniformity, water absorption, and market potential. In addition, the results of K-means algorithm showed that all the materials of choice for production of tile glaze are not placed in a single cluster. Therefore, each cluster should be evaluated separately. Unlike the classical approaches to the selection of materials, in the new approach, candidates for the selection of tile glaze are firstly clustered by K-means algorithm. Each cluster is independently ranked using free disposal hull model. Free disposal hull is a mathematical programming model based on data envelopment analysis. The final optimised portfolio of materials was determined using the genetic algorithm.

Capillary water absorption characteristics of some Cappadocian ignimbrites and the role of capillarity on their deterioration

Cappadocia stands out as one of the most important regions in Turkey for its natural, historical, and cultural heritages. The region is under the influence of wetting and drying and freezing and thawing weathering processes, which are largely controlled by the water content. Water migrates through rock pores via different processes, such as capillary water absorption, which is one of the most common ways observed in the Cappadocia region. In this study, a research program consisting mainly of laboratory studies was carried out to investigate the capillary water absorption characteristics of ignimbrites, which are the host rocks of many natural and historical heritage structures in Cappadocia. Accordingly, XRD analyses, mercury porosimeter, and capillary water absorption tests were performed. The pore size distribution, which is a function of welding degree, controls the capillary water absorption process of ignimbrites. Particularly, ignimbrites that have a uniform pore size distribution of around 5–10 µm reveal higher capillary water absorption potential. Ignimbrites have a considerable and variable potential in terms of capillarity, and the capillarity plays a major role on the deterioration and decomposition of many of the historical and natural heritage structures in the Cappadocia region.

Straw Yield and Quality: An Extra Motivation for the Introduction of Triticale in Mixed Farming Systems

Straw is a valuable by-product from cereal production. It is used for agricultural purposes as feed and bedding material for livestock. Additionally, cereal straw is a resource for the production of sustainable biomaterials and bio-energy. To meet the demands of these sectors substantial amounts of straw, with specific properties (e.g. water-holding capacity), are necessary. Since wheat breeding has mainly focused on grain yield rather than on straw yield other cereal species, such as triticale, can be of interest. Therefore, in this research the straw yield and water-holding capacity of four winter wheat and four winter triticale varieties were studied during two growing seasons. For both wheat and triticale there were differences in dry matter yield and percentage dry matter between growing seasons. Furthermore, depending on the growing season, there were significant differences in straw yield between the different wheat and triticale varieties. However, during both growing seasons, the straw yield obtained from the triticale varieties was significantly higher compared to the straw yield obtained from the wheat varieties. Concerning the water-holding capacity, it was concluded that the water absorption potential of triticale straw was higher compared to the water absorption potential of wheat straw. However, only in 2014 a significant difference between wheat and triticale was noted. So, it can be concluded that, besides the known advantages of triticale (performance on marginal soils, disease resistance, low fertilizer input, etc.), this crop has the potential to deliver high yields of high quality straw.

Performance of waste based alkaline mortars submitted to accelerated carbon dioxide curing

Carbon dioxide sequestration is crucial for targets limiting global warming could be achieved. This paper discloses results of an investigation concerning the performance of fly ash/waste glass alkaline-based mortars with two additives and recycled aggregates exposed to accelerated carbon dioxide curing. Mechanical properties as well as water absorption, drying shrinkage and carbon sequestration potential were studied on it. The results show that the mixtures with calcium hydroxide and sodium hydroxide concentration of 8M leads to the highest compressive strength (10MPa) which is high enough for the production of masonry blocks. Significant correlations between the flexural strength and the compressive strength were noticed. The mixtures show a low water absorption by immersion (9%) as well as by capillary (1.4kg/m2H0.5). The results of the modulus of elasticity show that increasing the sodium hydroxide molarity increased the stiffness of the mixtures. The results of drying shrinkage are in line with the results of the capillary water absorption and of the elastic modulus. A maximum CO2 sequestration (164kgCO2eq/m3) is noticed for the mixture with a sodium concentration of 8M based on the additive calcium hydroxide.

Electrochemical chloride extraction: Efficiency and impact on concrete containing 1% of NaCl

This paper aims to evaluate the efficiency of the electrochemical chloride extraction technique and its impact in concrete contaminated with 1% of chloride by monitoring chloride content, specific porosity, water absorption and corrosion potential, verifying the influence of variables reinforcement cover (1.0 and 3.0cm) and water/cement ratio (0.43 and 0.59). Results show that the concrete needs additional protection after chlorides extraction in order to prevent recontamination, since the porosity of the concrete increases with the application of the electrochemical chloride extraction. Average pore diameter increased 78% and 42% for concretes with w/c of 0.59 and 0.43, allowing the ingress of aggressive agents.

Brown Coal Dewatering Using Poly (Acrylamide-Co-Potassium Acrylic) Based Super Absorbent Polymers

With the rising cost of energy and fuel oils, clean coal technologies will continue to play an important role during the transition to a clean energy future. Victorian brown coals have high oxygen and moisture contents and hence low calorific value. This paper presents an alternative non evaporative drying technology for high moisture brown coals based on osmotic dewatering. This involves contacting and mixing brown coal with anionic super absorbent polymers (SAP) which are highly crossed linked synthetic co-polymers based on a cross-linked copolymer of acryl amide and potassium acrylate. The paper focuses on evaluating the water absorption potential of SAP in contact with 61% moisture Loy Yang brown coal, under varying SAP dosages for different contact times and conditions. The amount of water present in Loy Yang coal was reduced by approximately 57% during four hours of SAP contact. The extent of SAP brown coal drying is directly proportional to the SAP/coal weight ratio. It is observed that moisture content of fine brown coal can readily be reduced from about 59% to 38% in four hours at a 20% SAP/coal ratio.

Performance of EVA-Based Membranes for SCL in Hard Rock

The bonded property of multi-layered sprayed concrete tunnel linings (SCL) waterproofed with sprayed membranes means that the constituent materials will be exposed to the groundwater without any draining or mechanically separating measures. Moisture properties of the sprayed concrete and membrane materials are therefore important in order to establish the system properties of such linings. Ethyl-vinyl-acetate based sprayed membranes exhibit high water absorption potential under direct exposure to water, but are found to be significantly less hygroscopic and exhibit lower sorptivity (water absorption rate) than sprayed concrete. This material behavior explains the relatively dry in situ condition of the membrane that was observed. Measured in situ moisture content levels of the membrane material in tunnel linings have been found to vary within the range of 30–40 % of the maximum water absorption potential, and show a decreasing trend over the first 4 years after construction has been completed. A model for the mechanical loading, moisture condition and thermal exposure of the membrane and the resulting realistic parameters to be tested is presented. Laboratory testing methods for the membrane materials are evaluated considering possible loads, moisture and freezing exposure. Material testing of membrane materials was conducted with preconditioning to realistic moisture contents and under different temperature conditions including relevant freezing temperatures for tunnel linings. The main effects of the in situ moisture condition of the tested membrane materials are favorable tensile strengths in the range of 1.1–1.5 MPa and low risk of freeze–thaw damage. The crack bridging capacity of the tested membranes is found to be sensitive to temperature. With membrane thicknesses in the range of 3–4 mm, crack bridging capacity up to 4–6 mm opening of the crack width at 23 °C and approximately 1 mm opening at −3 °C was measured for the tested membranes. No significant reduction of the tensile bond strength could be demonstrated after 35 freeze–thaw cycles with −3 °C minimum temperature at the membrane location in the lining. Further work is required to verify the performance of the SCL system under exposure to high hydrostatic pressures and the effects of long term mechanical exposure.

Prediction and identification of capillary water absorption capacity of travertine dimension stone

The capillary transport mechanism has an important role on natural building stones that could be affected by moisture due to atmospheric conditions. Travertine with its natural porous structure is more sensitive to water which has a significant impact on durability. One of the important indicators of stone–water interaction is color variations, while natural stones with high capillary water absorption potential are in contact with water due to atmospheric conditions. As far as water absorption is concerned, water absorption by weight (WAW), water absorption by volume (n, apparent porosity), and capillary water absorption (CWA) parameters are in close relation with each other. To develop the relationships between capillary water absorption and the other water absorption parameters, regression and artificial neural network (ANN) analyses were performed. Within the scope of this study, the ANN models with three different input structures were established using various input variables in order to determine the relationship between CWA and the other parameters. The results of the different ANN structures of these models have been calculated and evaluated. For this purpose, travertine samples quarried from Denizli region in Turkey were studied. In order to evaluate the model results of regression and ANN methods, statistical performance evaluation parameters, i.e., the coefficient of correlation (CORR), efficiency (E), and root mean square error (RMSE), were calculated. In both regression and ANN models, reasonable coefficients of correlation were calculated. The capillary water absorption test is time consuming. The necessary periodical measurements make the process even more impractical. It is known that capillary water absorption is directly correlated with similar water absorption parameters such as water absorption by weight and apparent porosity. In this study, the estimation of capillary water absorption by means of other water absorption parameters is proposed. Moreover, there is no proposed classification in literature for natural stones based on their capillary water absorption. In the final stage of this study, by using the relationships between porosity and capillary water absorption, a capillary water absorption classification was proposed for travertine. Proposed classification consists of five categories and capillary water absorption coefficient which is ranging between very high (>68 g/m2 s0.5) and very low (<1 g/m2 s0.5). It is thought that this study could provide significant advantages in engineering practice and also make contribution to the related literature.

Water absorption and frost heaving of recycled aggregates

Water absorption and frost heaving of aggregates have a strong influence on the performance of a highway pavement. This is because several mechanical properties of aggregates change in direct response to water ingress and ground freezing. Recycled aggregates of different types are increasingly being used in pavements; however, their frost heaving and water absorption potential has not been fully investigated and documented. In the present study the opportunity was taken to study the water absorption and freeze–thaw properties of three different aggregates: (i) 100% recycled concrete aggregate, (ii) 100% natural aggregate from limestone rock, and (iii) 50% recycled concrete aggregate + 50% reclaimed asphalt pavement. For different particle size ranges, extensive tests were carried out for each of the above materials ((i)–(iii)) using the pyknometer and wire basket methods as well as simulation in a self-refrigerated unit. The following three kinds of density were measured: (a) over-dry, (b) saturated and surface dry, and (c) apparent particle density. The 100% natural aggregate had the lowest water absorption and highest densities ((a)–(c)) whereas the 100% recycled concrete aggregate had the highest water absorption. In contrast to the above findings, the frost heave potential was found to be much less sensitive to the aggregate type and particle size. Water absorption of recycled concrete aggregate decreased with increasing mean particle size. The measured relationships between density, grading and water absorption led to increased understanding of the behaviour of materials containing different fractions of recycled concrete aggregate and reclaimed asphalt pavement.

Effects of cathode catalyst layer design parameters on cold start behavior of polymer electrolyte fuel cells (PEFCs)

We present a theoretical study on the effects of key catalyst layer (CL) design parameters on the cold start behavior of a polymer electrolyte fuel cell (PEFC) using a three-dimensional transient cold start model developed in a previous study [1,2]. Among several CL design parameters, we adopt the ionomer fraction (ɛI) and weight ratio of Pt to carbon support (wt%Pt–C) in the cathode CL as CL design variables for this study. Therefore, other design parameters such as CL thickness and the oxygen reduction reaction (ORR) kinetic parameter are accordingly adjusted due to changes in ɛI and wt%Pt–C for cold start simulations. The calculated results confirm that these two design parameters provide control of the ice storage capacity and water absorption potential of the cathode CL, and consequently have a substantial influence on the cold start behavior of a PEFC. We provide a guideline to design and optimize a cathode CL and membrane electrode assembly (MEA) for improved PEFC cold start capability.

Corrosion Evaluation of Painted Steel Panels by Electrochemical Measurement

Abstract Paint is applied to effectively protect steel structures from corrosion. Coatings act as a barrier to a corrosive solution and transfer the electrical charge from the corrosive solution to the metal underneath the coating. The diffusion path of coatings may vary owing to the composition of the coatings. High-performance organic paint systems with two different primers and the same intermediate and top coats were used for the experiments. Both uncontrolled long-term testing and controlled laboratory testing were conducted to evaluate the performance of the coatings. Salt spray, alternating current (AC) impedance, and direct current (DC) corrosion were carried out on the fresh as well as exposed coated samples. Polarization resistance, coating capacitance, water absorption, and corrosion potential were studied to understand the causes of deterioration and to have faster assessment of durability of these paint formulations. To characterize the corrosion product, scanning electron microscopy (SEM) an...

Effect of chitosan addition on the surface properties of kenaf (Hibiscus cannabinus) paper

The present paper studies the effect of chitosan, cationic starch and polyvinyl alcohol (PVA) as sizing agents to enhance surface properties of kenaf paper. The polymers were incorporated into the sheets by spray application. The results clearly showed that the addition of chitosan to a sheet formed from beaten fibres had excellent improvement in surface properties, compared to the effect of other additives. Sizing quality of cationic starch fairly matched with the sizing quality of chitosan, however, it was able to reduce the water absorption potential of paper more than chitosan at a same concentration. In most other properties, particularly the most important property for printing papers, surface smoothness, chitosan-sized papers are superior to the paper sized with cationic starch or PVA.

Effectiveness of Class C fly ash as an expansive soil stabilizer

Fly ash produced in the combustion of subbituminous coals exhibits self-cementing characteristics and can be used in a wide range of stabilization applications. Fly ash treatment can effectively reduce the swell potential of highly plastic clays and prevent the swell beneath the smaller foundation pressures. The geology and climatic condition in Cyprus produce a wide distribution of expansive soils. These soils present problems in construction and possess a variety of undesirable characteristics such as low strength, high plasticity, difficult compaction and high swell potential. Laboratory test results on these soils indicate that fly ash is effective in ameliorating the texture and plasticity of the fly ash treated soils by reducing the amount of clay size particles, plasticity index and the swell potential. Cation exchange is one of the important reactions responsible for the improvement in the soil characteristics. In the study, cation exchange capacity (CEC) values have been used to indicate the changes in the mineralogy of the fly ash treated soils and explain the reduction in the plasticity and water absorption potential.

491 PB 163 A METHOD FOR QUANTIFYING PLANT AVAILABLE WATER-HOLDING CAPACITY AND WATER ABSORPTION POTENTIAL IN CONTAINER MEDIA UNDER PRODUCTION CONDITIONS

Hybrid impatiens were grown in 15 cm pots containing one of six root medium. After seven weeks, plant available water holding capacity (AWHC) was measured as the difference between the drained weight of the plant and pot after a one hour saturation and the weight of the pot when the plant wilted. Water absorption potential (WAP) was calculated as the capacity of each root medium to absorb applied irrigation water up to the AWHC and was measured at two moisture levels with top watering (two leaching fractions), drip irrigation (two leaching fractions) and flood subirrigation. Top watering moist media (initial AWHC = 35%) with leaching fractions of 30+ % was me most efficient method of rewetting media and was the only irrigation method tested to obtain WAP's of 100%. In comparison, flood subirrigation was the least efficient method of rewetting media with WAP of 27% for dry media (initial AWHC = 0%), and obtained a total WAP of 55% for moist media (initial AWHC = 23%). In media comparisons, the incorporation of a wetting agent into a 70% peat/30% bark mix at planting increased the WAP compared to the same media without a wetting agent with nine of the ten irrigation treatments.