Absorbance Capacity Research Articles

Study of water sorption properties for esparto grass ultimate fibre (ALFA fibre)

Natural fibres present multiple characteristics and are used in many fields such as textiles, technical or medical applications. In this context, we tried to use ligno-cellulosic fibres extracted from esparto (Stipa tenacissima L) as a support fiber in hygienic products. Due to their cellulosic nature, esparto fibres can provide a certain water sorption potential. In fact, fluff pulp was always used as a support fibre in the absorbent core structure of many hygienic products and this is particularly after adding super absorbent polymer (SAP). In this study, we choose to optimise the extraction process of these fibres using an experimental design method in order to obtain ultimate fibres and maximise their absorbent properties (absorbent capacity and retention).

A study of removal of Pb heavy metal ions from aqueous solution using lignite and a new cheap adsorbent (lignite washing plant tailings)

The present study determines the efficiency with which lignite and lignite washing plant tailings can adsorb Pb heavy metal ions. In the first experiment, the effect of size distribution on the absorbance capacity was investigated for the samples. Therefore, lignite sample was ground to five sizes ( d 80 = 0.600, 0.355, 0.250, 0.106 and 0.063 mm) under nitrogen (N 2), and the tailings sample was classified into seven fractions, along with the original state (original state: d 60 = 0.063, −1 + 0.600, −0.600 + 0.355, −0.355 + 0.250, −0.250 + 0.106, −0.106 + 0.063 and −0.063 mm). The test results showed that the optimum size distributions for lignite and tailings were d 80 = 0.063 mm and the original state ( d 60 = 0.063 mm), respectively. Simultaneously, the adsorption capacity results of the two optimum sizes were compared with each other, and the tailings sample ( d 60 = 0.063 mm) gave the best results, with 9.30 mg/g Pb ions adsorbed value. Therefore, in the second study, a series of laboratory experiments using 2 3 full factorial designs was conducted to determine the optimum pH, contact time and initial metal concentration using the original tailings sample. The experimental studies showed that pH 9, a 120 min contact time and 300 ppm initial metal concentration gave the best results, namely an adsorption of 29.92 mg Pb ions/g.

Influence of Bedding Material on Ammonia Emissions from Cattle Excreta

Dairy cattle barns are a major source of NH3 emissions to the atmosphere. Previous studies have shown that the bedding material used in the barn can influence the magnitude of NH3 emissions, but little is known about which bedding characteristics are important in this respect. The aims of this study were to assess, at a laboratory scale, the relative importance of the chemical [pH, cation exchange capacity (CEC), C:N] and physical (urine absorbance capacity, bulk density) characteristics of 5 bedding materials (chopped wheat straw, sand, pine shavings, chopped newspaper, chopped corn stalks, and recycled manure solids) on NH3 emissions from dairy cattle urine. Recycled manure solids were the most absorbent of the bedding types (4.2g of urine/g of bedding), and sand was the least (0.3g of urine/g of bedding). When beddings were soaked in urine to their absorbance capacities, NH3 emissions over 48h (expressed as a proportion of the urine N absorbed) were not significantly different among bedding types, despite differences in initial bedding pH, CEC, and C:N. When equal volumes of urine were applied to equal depths of dry bedding, NH3 emissions over 48h were significantly less from sand and pine shavings (23 and 42% of applied urine N, respectively) than from chopped newspaper, chopped corn stalks, and recycled manure solids (62, 68, and 65% of applied urine N, respectively), whereas emissions from chopped wheat straw (55% applied urine N) only differed significantly from that from sand. Differences in the chemical characteristics of the beddings did not explain differences in emission; NH3 emissions increased linearly with CEC contrary to expectations, and there was no significant relationship with initial bedding pH. The physical characteristics of bedding materials were of more importance, as NH3 emissions increased linearly with absorbance capacity and decreased as the bulk density of the packed beddings increased.

Comfort Properties of Heat Resistant Protective Workwear in Varying Conditions of Physical Activity and Environment. Part II: Perceived Comfort Response to Garments and its Relationship to Fabric Properties

Controlled garment wear trials are used to evaluate comfort response to a well-characterized set of heat-resistant workwear materials. Multiple categories of perceived comfort reactions to garment wear in diverse conditions are explained in terms of measured fabric properties assessed in Part I. The important role of fabric surface character, especially surface roughness and predicted skin contact area, is revealed. Fabric sweat management, measurable using a modified demand wettability test, is also identified as a useful predictor of moisture-related skin contact sensations. Heat-resistant fabric designs incorporating structural features that minimize skin contact, while also providing liquid absorption capacity, are predicted to show enhanced comfort performance. Blending of hydrophilic fibers and wicking finishes, however, do not necessarily improve the comfort perceptions in the tested scenarios. Selected fabric thermophysiological and sensorial properties are closely correlated with subjective comfort responses and the relationships are dependent on the wear conditions. Surface geometric roughness (SMD), number of contact points ( nk), and bending and shear rigidities are the decisive properties related to the tactile comfort. The vapor buffering index ( Bd) and liquid management properties, such as absorbent capacity ( V), initial rate ( Q1), and wet cling index ( ik) are the correlated indicators of nonabsorbency, clinginess, and sensation of clamminess. In particular, apparent water ratio ( A/ T), which can be assessed by a modified demand wettability test, is a good predictor of perception of clamminess in the cool-down period after exercise or a hot situation.

Electrospray mass spectrometry to study lake water DOM and effects of microbial degradation

Qualitative analysis of lake water dissolved organic matter (DOM) was carried out using electrospray ionization mass spectrometry (ESI MS) without prior clean-up or chromatography, showing the potential of ESI MS as a rapid method to analyse qualitative differences between DOM with different environmental properties. Spectra were evaluated in terms of the relative ion abundance in certain mass to charge ranges (m/z range), and the mass-to-charge average (m/z average). Lake water DOM from two different sources was used. In addition, DOM from both sources that had been subjected to microbial degradation under different oxygen regimes was analysed. ESI MS results were compared with those of UV absorbance and pollutant binding capacity (pyrene and atrazine). The results from all methods indicated qualitative differences between the DOM from different lakes, but only minor qualitative changes when comparing oxic and anoxic degradation. To detect those small differences the m/z range proved to be the more sensitive evaluation method, compared to the m/z average.

Particle Containment and Immobilization in Roll Good Materials

Integration of functional particles such as superabsorbent or zeolite powders into a roll good provides a way of imparting a virtually unlimited range of desired properties to a two-dimensional structure. This paper examines and compares the efficiency of various powder containment methods and their effect on properties such as absorbent capacity and fluid permeability. Methods of particle containment and/or immobilization include particle-to-particle adhesion, particle-to-fiber adhesion, and powder entrapment between bonded fibers.

Influence of Structural Properties on Non-Impact Printability of Nanostructured Silica–Polymer Coatings

The ink jet printing properties of papers coated with two different types of aggregated silica were compared. The structure of the nanoporous aggregates has been investigated with different techniques such as BET and CTAB surface area, Hg porometry and light scattering. The aggregates were thereafter mixed with polyvinylalcohol (PVA). The affinity of the PVA for the silica surface has been studied through adsorption isotherms at pH 5 and 9. It appears that the affinity is much more important at pH 5. PVA– silica slurries were prepared at pH 5 and coated on a non-coated common copier paper and finally printed. Swelling experiments and transmission electron microscopy have been performed on the coatings in order to have additional information on its structure. Black and white image analysis of typographic characters printed on the coatings show that smoothness of contours, gray level, contrast, definition, surface area of the typographic characters depend mostly on the structural properties of the silica, but also on its compatibility with the binder. The combination of both effects determines how important the remaining free porous volume accessible to ink fluids will be, and ultimately how the printing properties, such as shade and pixel resolution, will be. When pores are too large, they become filled with polymer and the silica aggregates lose their absorbency capacity.

Cultural system affects fruit quality and antioxidant capacity in strawberries.

Cultural system [hill plasticulture (HC) versus matted row (MR)] and genotype interactions affected strawberry fruit quality. In general, fruit soluble solids content, total sugar, fructose, glucose, ascorbic acid, titratable acid, and citric acid contents were increased in the HC system. Fruit from HC also had higher flavonoid contents and antioxidant capacities. Strawberry fruit contains flavonols as well as other phenolic compounds such as anthocyanins and phenolic acids. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside, pelargonidin 3-rutinoside, and pelargonidin 3-glucoside-succinate were the predominant anthocyanins in strawberry fruit. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins in either system. Strawberry fruit from the HC system had significantly higher amounts of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate. Fruits from plants grown in the MR system generally had the lowest contents of phenolic acids, flavonols, and anthocyanins. Strawberry fruit grown under HC conditions had significantly higher peroxyl radicals (ROO*) absorbance capacity (ORAC).

Applications of a new method for measuring the total oxyradical scavenging capacity in marine invertebrates

A new method is described for measuring the total oxyradical scavenging capacity (TOSC) in biological tissues. The TOSC-assay is based on the reaction between peroxyl radicals and α-keto-γ-methiolbutyric acid which is oxidized to ethylene. The presence within the tissues of molecules that scavenge for peroxyl radicals generated by thermal homolysis of 2,2′ azo-bis-amidinopropane quantitatively reduce ethylene production. Cytosol from invertebrates showed a higher ROO ° absorbance capacity than that of rat liver and in all the species endogenous soluble antioxidants provided greater protection than proteins. The expected contribution of GSH, ascorbic acid and uric acid accounted for only 35% of the measured TOSC values. This method is useful for assessing the biological resistance to oxidative stress and its relationship to environmental pollutants in quantifiable terms.

Polymer‐grafted cellulose fibers. I. Enhanced water absorbency and tensile strength

To enhance the water absorbency of wood fibers, various acrylic monomers were grafted to these fibers using cerium IV initiation followed by base hydrolysis. The absorbent capacity of hydrolyzed methyl acrylate- or acrylonitrile-grafted wood pulp fibers was an order of magnitude greater than ungrafted pulp fibers. A portion of this enhanced absorbency could be attributed to graft-induced osmotic forces. Enhanced absorbency was relatively independent of wood fiber type. Paper handsheets incorporating 20% grafted fibers had a fivefold increase in absorbent capacity, a twofold increase in dry tensile strength, a threefold or greater increase in wet tensile strength, and were more stretchable. In addition to enhanced absorbent capacity, the rate of absorbency was approximately 50% greater. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1463–1469, 1997

Polymer-grafted cellulose fibers. I. Enhanced water absorbency and tensile strength

To enhance the water absorbency of wood fibers, various acrylic monomers were grafted to these fibers using cerium IV initiation followed by base hydrolysis. The absorbent capacity of hydrolyzed methyl acrylate- or acrylonitrile-grafted wood pulp fibers was an order of magnitude greater than ungrafted pulp fibers. A portion of this enhanced absorbency could be attributed to graft-induced osmotic forces. Enhanced absorbency was relatively independent of wood fiber type. Paper handsheets incorporating 20% grafted fibers had a fivefold increase in absorbent capacity, a twofold increase in dry tensile strength, a threefold or greater increase in wet tensile strength, and were more stretchable. In addition to enhanced absorbent capacity, the rate of absorbency was approximately 50% greater. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1463–1469, 1997

Performance predictions of alternative, low cost absorbents for open-cycle absorption solar cooling

To achieve solar fractions greater than 0.90 using the open-cycle absorption refrigeration system, considerable sorbent solution storage is necessary. Sorbent solutions currently under consideration, such as aqueous solutions of lithium chloride and lithium bromide, may be too costly to exploit the open-cycle storage concept. Having identified the absorber as the system component whose performance is affected the most by a change in absorbent, an absorber model was selected from available literature pertaining to simultaneous heat and mass transfer. Low cost absorbent candidates were selected and their physical properties were either located in the literature, measured, or estimated. Absorber operating parameters were selected and the model was then used to estimate absorber performance for each absorbent in terms of cooling capacity per unit of absorber area. After specifying system parameters such as absorber capacity and cooling load, the absorber area, absorbent cost, and sorbent solution pumping power and storage volume were estimated for each candidate. The most promising of the absorbents considered was a mixture of two parts lithium chloride and one part zinc chloride. The estimated capacities per unit absorber area were 50–70% less than those of lithium bromide; however, the lithium bromide cost for a system sized to cool a 190 m 2 residential structure was estimated to be eight times that for the lithium-zinc chloride mixture. Both the lithium-zinc chloride mixture and lithium bromide solutions had estimated pumping powers of less than 0.1 kW. The solubility of the lithium-zinc chloride mixture at absorber conditions was improved over that of lithium bromide, reducing the risk of solidification of the solution.

The effects of adding molassed sugar beet pulp on the nutritive Value of silage

In recent years there has been increasing interest in adding concentrate feedstuffs at ensiling for a number of reasons. Firstly, from a management point of view, it can be an easy method of feeding a concentrate supplement and secondly feedstuffs may have some absorbent capacity and thus reduce effluent production. However, it is important that the feeding value of the material added is retained during the ensiling process and that the silage preserves well. The objective of this experiment was to assess the nutritive value of silage made by adding dried molassed sugar beet pulp to grass at ensiling, when fed to castrated sheep.

COMPARATIVE THERMOPHYSIOLOGICAL TESTS ON BLANKETS MADE FROM WOOL AND ACRYLIC-FIBRE–COTTON BLENDS

An account is given of the determination of the thermophysiological properties of two blankets, one made from wool and the other from an acrylic-fibre–cotton blend but otherwise matched in weight and fibre diameter, by laboratory measurements as well as by climatic-chamber tests with human subjects. The tests show that the blanket made from wool confers a higher degree of thermal insulation and possesses better moisture-transport properties under stationary conditions, combined with better moisture absorbance and buffering capacity under transient conditions, than the blanket made from the acrylic-fibre–cotton blend. Consequently, in the climatic-chamber tests under warm and humid conditions, the test persons subjectively preferred the woollen blanket for its thermophysiological comfort.

Relation of GIX antigen of thymocytes to envelope glycoprotein of murine leukemia virus.

Expression of Gix surface antigen on thymocytes is an inherited mendelian train of certain strains of mice. We report here the following new findings: (a) Gix antigen was found free in the serum of Gix+ mouse strains. (b) Expression vs. nonexpression of Gix antigen was invariably correlated with presence or absence of the group-specific antigen of Murine leukemia virus (MuLV) gp69/71 in the serum of mice of inbred and segregating populations. (c) Gix antigen could be removed from normal Gix+ mouse serum by precipitation with antiserum to MuLV gp 69/71. (d) Anti-gp69/71 serum was weakly cytotoxic for Gix+ thymocytes, and partially blocked the cytotoxic activity of Gix antibody for Gix+ thymocytes. (e) Purified AKR virus absorbed Gix activity, and disruption of the virions did not increase their absorbing capacity. These serological data indicate that Gix antigen is a constituent of gp69/71, the glycoprotein which is the major component of the MuLV envelope. On present evidence, Gix antigen is represented in intact virions and is probably accessible to Gix antibody.