Shrinkage of highly oriented gel-spun polymeric fibres

Summary The melting and shrinking process of gel-spun hot-drawn UHMWPE fibres has been investigated. Instead of being superheated, the highly oriented fibres start to melt at the fibre ends and shear bands, at a temperature near the equilibrium melting temperature of polyethylene. For draw ratios of 40, the fibre transforms into a ribbon shape upon melting. This change in shape could be prevented by constrained heating before shrinkage. Ribbon-like melting was also observed for gel-spun hot-drawn poly(L-lactide) fibres.     

The persuasive effects of personalization through: name mentioning in a smoking cessation message

Mentioning the recipient’s name in a persuasive message is one way to personalize messages in an attempt to increase persuasion. However, this type of personalization may lead to a self-threat that activates defensive reactions and to a subsequent decrease in persuasion. A self-affirmation procedure that induces open-mindedness may prevent this drawback. Smokers were exposed to a message advocating smoking cessation in one of three experimental conditions presenting: A standard text, a text with the recipient’s name incorporated four times, or a text with the recipient’s name incorporated twelve times. The extent to which smokers indicated at pretest to value their health was used as a measure of personal relevance of the message, and tested as a moderator. Half of the smokers was exposed to a self-affirmation procedure before they read the text. The dependent variable was the intention to quit smoking. When health value was moderate, mentioning the recipient’s name twelve times induced a defensive reaction, significantly lowering persuasion. This was supported by the observation that self-affirmation prevented this effect. When health value was high, mentioning the recipient’s name twelve times significantly increased persuasion. However, when self-affirmation was applied, persuasion was significantly lowered. The effects of mentioning the recipient’s name depend on individual differences in personal relevance of the message (health value) before exposure to the message: Name mentioning can increase, but also decrease persuasion, through defensive processes.     

Bench-scale WGS membrane reactor for CO2 capture with co-production of H2

This study investigated the water-gas shift reaction in a bench-scale membrane reactor (M-WGS), where three supported Pd membranes of 44 cm in length and ca. 6 μm in thickness were used, reaching a total membrane surface area of 580.6 cm². The WGS reaction was studied with the syngas mixture: 4.0% CO, 19.2% CO₂, 15.4% H₂O, 1.2% CH₄ and 60.1% H₂, under high temperature/pressure conditions: T = 673 K, p_feed = 20–35 bar(a), p_perm = 15 bar(a), mimicking CO₂ capture with co-production of H₂ in a natural gas fired power plant. High reaction pressure and high permeation of Pd membranes allowed for near complete CO conversion and H₂ recovery. Both the membranes and the membrane reactor demonstrated a long-term stability under the investigated conditions, indicating the potential of M-WGS to substitute conventional systems.     

Effect of different levels of rapidly degradable carbohydrates calculated by a simple rumen model on performance of lactating dairy cows

Aggregating rumen degradation characteristics of different carbohydrate components into the term modeled rapidly degradable carbohydrates (mRDC) can simplify diet formulation by accounting for differences in rate and extent of carbohydrate degradation within and between feedstuffs. This study sought to evaluate responses of lactating dairy cows to diets formulated with increasing levels of mRDC, keeping the supply of other nutrients as constant as possible. The mRDC content of feedstuffs was calculated based on a simple rumen model including soluble, washable, and nonwashable but potentially degradable fractions, as well as the fractional degradation and passage rates, of sugar, starch, neutral detergent fiber, and other carbohydrates. The mRDC term effectively represents the total amount of carbohydrates degraded in the rumen within 2 h after ingestion. Fifty-two lactating Holstein cows (of which 4 were rumen fistulated) were assigned to 4 treatments in a 4 × 4 Latin square design. Treatments were fed as a total mixed ration consisting of 25.4% corn silage, 23.1% grass silage, 11.6% grass hay, and 39.9% concentrate on a dry matter basis. Differences in mRDC were created by exchanging nonforage neutral detergent fiber-rich ingredients (mainly sugar beet pulp) with starch-rich ingredients (mainly wheat) and by exchanging corn (slowly degradable starch) with wheat (rapidly degradable starch) in the concentrate, resulting in 4 treatments that varied in dietary mRDC level of 167, 181, 194, or 208 g/kg of dry matter. Level of mRDC did not affect dry matter intake. Fat- and protein-corrected milk production and milk fat and lactose yield were greatest at 181 mRDC and decreased with further increases in mRDC. Milk protein yield and concentration increased with increasing mRDC level. Mean rumen pH and diurnal variation in ruminal pH did not differ between treatments. Total daily meal time and number of visits per meal were smaller at 181 and 194 mRDC. Despite milk production responses, increasing dietary mRDC levels, while maintaining net energy and intestinal digestible protein as well as other nutrients at similar levels, did not influence rumen pH parameter estimates and had minor effects on feeding behavior. These results indicate that aggregating rapidly degradable carbohydrate content into one term may be a simple way to further improve predictability of production responses in practical diet formulation for lactating dairy cows.     

Stripping medium requirement in continuous countercurrent deodorization

A mathematical formula was derived that allows the stripping steam requirement of the countercurrent deodorization process to be calculated as a function of system pressure, vapor pressure of the pure volatile compound, initial and final volatiles contents, and the number of transfer units (an equipment parameter) of the countercurrent deodorizer. Just as in batch or cross-flow deodorization systems, the steam requirement in countercurrent systems is proportional to the system pressure and inversely proportional to the vapor pressure of the pure volatile compound. Increasing the number of transfer units (for instance, by increasing column height) to more than two makes the countercurrent system require less steam than cross-flow systems with a vaporization efficiency of 0.6. In addition, the short residence time in a countercurrent deodorization column minimizes side reactions and allows the deodorization temperature to be raised without generating unwanted by-products such as trans-isomers and/or oligomers of unsaturated fatty acids. The increased deodorization temperature increases the vapor pressure of the pure volatiles and leads to further savings in stripping medium and motive steam. Countercurrent deodorization systems therefore require less energy than cross-flow deodorization systems and/or produce oil with fewer unwanted by-products.     

Geochemical modeling of leaching from MSWI air-pollution-control residues

This paper provides an improved understanding of the leaching behavior of waste incineration air-pollution-control (APC) residues in a long-term perspective. Leaching was investigated by a series of batch experiments reflecting leaching conditions after initial washout of highly soluble salts from residues. Leaching experiments were performed at a range of pH-values using carbonated and noncarbonated versions of two APC residues. The leaching data were evaluated by geochemical speciation modeling and discussed with respect to possible solubility control. The leaching of major elements as well as trace elements was generally found to be strongly dependent on pH. As leaching characterization was performed in the absence of high salt levels, the presented results represent long-term leaching after initial washout from a disposal site, that is, liquid-to-solid ratios above 1-2 L/kg. The leaching of Al, Ba, Ca, Cr, Pb, S, Si, V, and Zn was found influenced by solubility control from A12O3, Al(OH)3, Ba(S,Cr)04 solid solutions, BaSO4, Ca6Al2(SO4)3(OH)12 x 26H2O, CaAl2Si4O12 x 2H2O, Ca(OH)2, CaSiO3, CaSO4 x 2H2O, CaZn2(OH)6 x 2H2O, KAlSi2O6, PbCO3, PbCrO4, Pb2O3, Pb2V2O7, Pb3(VO4)2, ZnO, Zn2SiO4, and ZnSiO3. The presented dataset and modeling results form a thorough contribution to the assessment of long-term leaching behavior of APC residues under a wide range of conditions.     

Effect of Dietary Starch or Micro Algae Supplementation on Rumen Fermentation and Milk Fatty Acid Composition of Dairy Cows

Two experiments with rumen-fistulated dairy cows were conducted to evaluate the effects of feeding docosahexaenoic acid (DHA; C22:6 n-3)-enriched diets or diets provoking a decreased rumen pH on milk fatty acid composition. In the first experiment, dietary treatments were tested during 21-d experimental periods in a 4 × 4 Latin square design. Diets included a control diet, a starch-rich diet, a bicarbonate-buffered starch-rich diet, and a diet supplemented with DHA-enriched micro algae [Schizochytrium sp., 43.0 g/kg of dry matter intake (DMI)]. Algae were supplemented directly through the rumen fistula. The total mixed ration consisted of grass silage, corn silage, soybean meal, and a standard or glucogenic concentrate. The glucogenic and buffered glucogenic diet had no effect on rumen fermentation and milk fatty acid composition because, unexpectedly, no reduced rumen pH was detected. The algae diet had no effect on rumen pH but provoked decreased butyrate and increased isovalerate molar proportions in the rumen. In addition, algae supplementation affected rumen biohydrogenation of linoleic and linolenic acid as reflected in the modified milk fatty acid composition toward increased conjugated linoleic acid (CLA) cis-9 trans-11, CLA trans-9 cis-11, C18:1 trans-10, C18:1 trans-11, and C22:6 n-3 concentrations. Concomitantly, on average, a 45% decrease in DMI and milk yield was observed. Based on these drastic and impractical results, a second animal experiment was performed for 20 d in which 9.35 g/kg of total DMI of algae were incorporated in the concentrate and supplemented to 3 rumen-fistulated cows. Algae concentrate feeding increased rumen pH, which was associated with decreased rumen short-chain fatty acid concentrations. Moreover, a different shift in rumen short-chain fatty acid proportions was observed compared with the first experiment because molar proportions of butyrate, isobutyrate, and isovalerate increased, whereas acetate molar proportion decreased. The milk fatty acid profile changed as in experiment 1. However, the decrease in DMI and milk yield was less pronounced (on average 10%) at this algae supplementation level, whereas milk fat percentage decreased from 47.9 to 22.0 g/kg of milk after algae treatment. In conclusion, an algae supplementation level of about 10 g/kg of DMI proved effective to reduce the milk fat content and to modify the milk fatty acid composition toward increased CLA cis-9 trans-11, C18:1 trans, and DHA concentrations.     

The Effect of Silage and Concentrate Type on Intake Behavior, Rumen Function, and Milk Production in Dairy Cows in Early and Late Lactation

The objective of this experiment was to evaluate the effect of feeding total mixed rations (TMR) that differ in structural and nonstructural carbohydrates to dairy cows in early and late lactation on short-term feed intake, dry matter intake (DMI), rumen fermentation variables, and milk yield. A 5 × 5 Latin square experiment with 15 dairy cows was repeated during early and late lactation. The 5 treatments were a TMR with (all on dry matter basis) 55% roughage (a 50:50 mixture of corn silage and grass silage) and 45% concentrate (a 50:50 mixture of concentrate rich in structural carbohydrates and concentrate rich in nonstructural carbohydrates; treatment CON), a TMR with the concentrate mixture and 55% grass silage (RGS) or 55% corn silage (RCS), and a TMR with the roughage mixture and 45% of the concentrate rich in structural carbohydrates (CSC) or the concentrate rich in nonstructural carbohydrates (CNS). Meal criteria, determined using the Gaussian-Gaussian-Weibull method per animal per treatment, showed an interaction between lactation stage and treatment. Feed intake behavior variables were therefore calculated with meal criteria per treatment-lactation stage combination. Differences in feed intake behavior were more pronounced between treatments differing in roughage composition than between treatments differing in concentrate composition, probably related to larger differences in chemical composition and particle size between corn silage and grass silage than between the 2 concentrates. The number of meals was similar between treatments, but eating time was greater in RGS (227 min/d) and lesser in RCS (177 min/d) than the other treatments. Intake rate increased when the amount of grass silage decreased, whereas meal duration decreased simultaneously. These effects were in line with a decreased DMI of the RGS diet vs. the other treatments, probably related to the high neutral detergent fiber (NDF) content. However, this effect was not found in CSC, although NDF content of the TMR, fractional clearance rate of NDF, and fractional degradation rate of NDF was similar between CSC and RGS. Rumen fluid pH was lesser, and molar proportions of acetic acid and of propionic acid were lesser and greater, respectively, in RCS compared with all other diets. Milk production did not differ between treatments. There was no effect of type of concentrate on milk composition, but diet RCS resulted in a lesser milk fat content and greater milk protein content than diet RGS. Lactation stage did affect short-term feed intake behavior and DMI, although different grass silages were fed during early and late lactation. The results indicate that short-term feed intake behavior is related to DMI and therefore may be a helpful tool in optimizing DMI and milk production in high-production dairy cows.