Comparison of perceived comfort differences between standard and experimental load carriage systems

The current popularity of backpack-type load carriage systems (LCS) by students has precipitated a prevalence of postural abnormalities and pain. This study compared subjective perceptual comfort in standard and vertically loaded LCSs. Sixteen females ages 18-23 years rated their personal LCSs for perceived shoulder, neck, and lower back comfort and for overall comfort, each day for two weeks using 100 mm visual analogue scales (VAS). Each scale contained polar extremities of 'very comfortable' to 'very uncomfortable' and a vertical mark placed on the 100 mm line by the participants indicated their perception of comfort. Following two weeks, participants were given LCSs that distributed the weight vertically and were asked to rate the system in the same way for an additional two-week period. Statistical analysis revealed significant differences in shoulder (p=0.015), neck (p=0.005), and lower back (p=0.036) comfort and overall comfort (p=0.001) between the participants' personal LCSs and the experimental LCS. In conclusion, vertical load placement may redistribute the load in a manner that reduces symptoms of selected anatomical discomfort.     

Formation of asymmetric cellulose acetate membranes

Cellulose acetate membranes were prepared from casting solutions containing dioxane as a solvent and varying concentrations (up to 6%) of maleic acid as an additive. Coagulation took place in water at different temperatures. The effect of these variables on membrane structure and membrane properties is related to two phenomena of phase separation in the system cellulose acetate/dioxane/water, viz. gelation in the toplayer and liquid-liquid phase separation in the sublayer of the membrane. We adopted a solution transport model which correlates membrane flux with the skin thickness and membrane salt rejection with the compactness (microstructure) in the skin. Effects of variables such as maleic acid concentration and coagulation temperature on the position of curves in the phase diagram and on membrane properties are discussed. It is concluded that more work should follow on the kinetics of the phase changes mentioned.     

Liver function following pregnancy complicated by the HELLP syndrome

Serum levels of aminotransferases, lactate dehydrogenase, gammaglutamyl transferase, alkaline phosphatase, albumin and conjugated bilirubin, measured in 54 women at a median of 31 months (range 3-101) after pregnancies complicated by the HELLP syndrome, were not elevated. Total bilirubin levels, however, were elevated in 20% of these women; this represents a significant difference from the prevalence in 151 women with a previous normal pregnancy (chi2 = 12.23, P < 0.001), or in the normal female population (chi2 = 22.34, P < 0.00001). This raises the possibility that a dysfunction of the bilirubin-conjugating mechanism represents a risk factor for the development of the HELLP syndrome.     

SiSiC Heat Exchangers for Recuperative Gas Burners with Highly Structured Surface Elements

Heat exchangers are used in gas burners as recuperators. Their efficiency is proportional to their surface which is usually limited by the burner length and diameter. Ceramic recuperators used nowadays in industrial burners are tubular. We studied and developed a new generation of ceramic heat exchanger with the final goal of increasing the efficiency or, at similar efficiencies, of reducing their size and weight. A commercial SiSiC heat exchanger component was used to guarantee safety and robustness. The use of structured textile geometries followed by their conversion into a ceramic is the main innovation of this work.     

Nanofractionation spotter technology for rapid contactless and high-resolution deposition of LC eluent for further off-line analysis

The development of a contactless postcolumn spotter technology capable of rapidly and accurately depositing LC eluent onto another platform (e.g., 1536-well microtiter plates) is described. Many detection methodologies are suitable for online analysis, such as mass spectrometry, UV-vis, and fluorescence. In some cases, when online analysis is less suitable, off-line postcolumn analysis is the methodology of choice and usually relies on LC-based fractionation prior to detection (e.g., MALDI-MS, Raman spectrsocopy, biochemical assays). As fractionation generally involves loss in resolution, the technology described here allows high-resolution contactless fractionation by tailoring the fractionation frequency to the chromatographic peaks and mixing in of postcolumn reagents. Droplet ejection at frequencies of at least 6 Hz could be performed in the nanoliter to low microliter range with repeatabilities of ～6%. Furthermore, multiple droplets can be ejected at the same position thereby allowing adjustment of fractionation volume and speed. The technology was evaluated, optimized, and validated prior to two proof-of-principle demonstrations comprising off-line chemical detection of injected fluorescein and off-line postcolumn biochemical detection of acetylcholine-binding protein ligands, both based on 1536-well plate reader analysis.     

Wärmebehandlung von Sinterstahl-Präzisionsteilen: II. Prozess- und Anlagentechnik

For improving the quality of powder metallurgy precision parts, about 2/3 of them are commonly heat treated. Part 2 of this paper explains the process parameters and the required furnace technology and shows some applications. In gas carburizing of powder metallurgical parts the case depth increases extremely with increased porosity, even causing through carburizing of PM parts. Low pressure carburizing is limiting the carbon diffusion to the surface area and therefore causes a quite sharp drop of the carbon profile near the surface. For improvements of the hardenability at the surface of sintered material with low hardenability, low pressure carbonitriding can be applied. The substitution of oil quenching devices by “dry” gas quenching units has big advantages for treating PM parts, since no more washing ist required, and the distortion of the parts can be reduced. Nowadays modern high pressure gas quenching devices can reach quenching rates of medium speed high quality quenching oils. A FEM-simulation of a gas quenching device and some of the latest treatment results will be presented.     

Development of the ultrasonic conditions as an advanced technique for extraction of phenolic compounds from Eucalyptus robusta

This study is designed to develop ultrasonic conditions as an advanced technique for optimal recovery of phenolics and antioxidants from Eucalyptus robusta leaf and to evaluate the impact of solvents, temperature, sonication time and power on ultrasound-assisted extraction of these compounds. Temperature has the greatest impact on the total phenolic content (TPC) yield followed by time and power. A yield of 163.68 ± 2.13 mg GAE/g of TPC is observed using 250 W ultrasonic power for 90 min at 60°C with water. This study validates UAE as an efficient, green, and sustainable technique for extracting phenolics from E. robusta.