A low-energy solvent separation method

This paper presents a new low-energy method to separate solvents from polymers. The method is based upon the lower critical solution temperature (LCST), a phenomenon exhibited by all nonpolar polymer-solvent systems. Three key issues concerning this new separation method are discussed for the specific system of high cis polybutadiene in a commercial grade n-hexane. The first issue, energy cost, is greatly reduced from present commercial separation processes by avoiding the liquid-vapor phase transition for more than half of the solvent. The predicted energy cost for the new method (not including inefficiencies) is about 15 percent of the present energy cost (including inefficiencies). The second issue, recycling of the dilute phase with terminator, is shown not to be a serious problem, and a solution is suggested based upon available methods. The third issue discussed, and perhaps the most difficult, is the physical separation of the two phases. This is solved by inducing spinodal decomposition, which leads to rapid gravity separation. Several alternative separation scenarios based upon this idea are presented at the end of the article.     

Immunochemical quantification of heat denaturation of camel ( Camelus dromedarius ) whey proteins

The major whey proteins IgG, serum albumin and alpha-lactalbumin were purified from camel milk using gel permeation and ion-exchange chromatography. Specific antisera against each of them were raised and used to quantify their heat denaturation in early or mature milk over a range of 60-90 degrees C for 10-60 min using the single radial immunodiffusion technique. The heat denaturation midpoints for the mature milk heated 30 min were 67.2, 73.0 and 77.5 degrees C for IgG, albumin and alpha-lactalbumin respectively. The early milk was more sensitive to heat treatment with coagulation at low temperature and heat denaturation midpoints of 64.8, 71.6 and 72.6 degrees C respectively. This difference was related to the high IgG content of the early milk (12.6 mg/ml v. 0.5 mg/ml for the mature milk) and stresses the importance of monitoring the IgG level of milk to assess the absence of colostrum.     

Estimates of embodied global energy and air-emission intensities of Japanese products for building a Japanese input-output life cycle assessment database with a global system boundary

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input-output LCA method with a global link input-output model that defines a global system boundary grounded in a simplified multiregional input-output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input-output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains.     

Radical scavenging compounds in onion skin

Two major flavonols (F_I and F_II) in onion skin were isolated. According to the ultraviolet–visible absorption spectra, F_I and F_II fractions were thought to be 3,5,7,3′-OH and 3 (5),7,3′,4′-OH of flavonol, respectively. After acid hydrolysis of the two fractions, F_I was found to consist of quercetin and glucose, but F_II only contained quercetin. F_I and F_II were confirmed by fast atom bombardment as quercetin 4′-glucoside and quercetin, respectively. The F_I and F_II fractions exhibited potent radical scavenging activity against DPPH, superoxide anion (O₂·^-) , and hydroxyl (·OH) radicals.     

Liquid injection molding II. Mechanical design and characterization of a RIM machine

A unique liquid injection molding machine for polyurethane was designed and built to process a large quantity of polyurethane in a short period of time. This machine has a continuously variable flow rate. Using inexpensive, low capacity gear pumps, 5 gallon hydraulic accumulators were charged with fluid components. The fluid can be pumped into the accumulators at low pressure followed by nitrogen gas addition to the bladders to raise the fluid pressure, or the charging pumps can pump up the accumulators against an existing pressure. The two components were then discharged under pressure through linkage activated ball valves and mixed together in a mixing chamber. The system provided for a very low pressure loss during discharge, resulting in high fluid velocity. Extremely high flow rates were possible: approximately 1440 lb/min at 2500 psi, a pressure less than the maximum possible system pressure. This system delivers large flow rates of high quality urethane while still maintaining its simplicity, light weight, and relative low cost.     

Functional subcaste discrimination (foragers and brood-tenders) in the antCamponotus vagus scop.: polymorphism of cuticular hydrocarbon patterns

In the antCamponotus vagus, when selected foragers that had been earlier removed from the foraging arena and brood-tenders that had been earlier removed from the nest were placed together in a foraging arena, most of the brood-tenders and only a few of the selected foragers were carried back to the nest by nonselected foragers. We hypothesize that cuticular hydrocarbons serve as a cue that allows foragers to discriminate between members of their own subcaste and brood-tenders. It has been established that the proportions of certain hydrocarbons, which are the same regardless of the colony studied, vary from one worker subcaste to another and thus constitute a specific chemical signature. These hydrocarbons belong to a wide range of chemical families (alkanes, monomethylalkanes, and dimethylalkanes). The greatest differences between the two subcastes were observed on the thorax of workers. Principal component analyses performed on the hydrocarbons (or hydrocarbon combinations) corresponding to the 45 main peaks in the cuticular profiles of the head and thorax of brood-tenders and foragers of several colonies show that there exist quantitative differences between the various signatures that characterize the colony, the worker subcastes, and the various body parts within the same species, which can be classified in a hierarchy where the differences between worker subcastes are less pronounced than those between body parts or between colonies.     

Clinical and Molecular Characterization of Patients with Mucopolysaccharidosis Type I in an Algerian Series

Mucopolysaccharidoses (MPS’s) represent a subgroup of lysosomal storage diseases related to a deficiency of enzymes that catalyze glycosaminoglycans degradation. Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive disorder caused by a deficiency of α-l-iduronidase encoded by the IDUA gene. Partially degraded heparan sulfate and dermatan sulfate accumulate progressively and lead to multiorgan dysfunction and damage. The aim of this study is to describe the clinical, biochemical, and molecular characteristics of 13 Algerian patients from 11 distinct families. MPS I diagnosis was confirmed by molecular study of the patients’ IDUA gene. Clinical features at the diagnosis and during the follow-up are reported. Eighty-four percent of the studied patients presented with a mild clinical phenotype. Molecular study of the IDUA gene allowed the characterization of four pathological variations at the homozygous or compound heterozygote status: IDUA NM_00203.4:c.1598C>G-p.(Pro533Arg) in 21/26 alleles, IDUA NM_00203.4:c.532G>A-p.(Glu178Lys) in 2/26 alleles, IDUA NM_00203.4:c.501C>G-p.(Tyr167*) in 2/26 alleles, and IDUA NM_00203. 4: c.1743C>G-p.(Tyr581*) in 1/26 alleles. This molecular study unveils the predominance of p.(Pro533Arg) variation in our MPS I patients. In this series, the occurrence of some clinical features linked to the Scheie syndrome is consistent with the literature, such as systematic valvulopathies, corneal opacity, and umbilical hernia; however, storage signs, facial dysmorphic features, and hepatomegaly were more frequent in our series. Screening measures for these debilitating diseases in highly consanguineous at-risk populations must be considered a priority health problem.     

A study of tailored blank welding between mild steel sheet and zn-coated steel sheet by CO2 laser beam

Research was conducted on tailored blank welding between mild steel sheet and Zn-coated steel sheet using CO₂ laser beam. The materials used in this study were low carbon steel sheets with a thickness of 1.2 mm and Zn-coated steel sheet with the same thickness and 6.3 μm Zn coating. Experiments were conducted by applying the Taguchi method to obtain optimum conditions for the application of this tailored blank laser welding method in practical manufacturing processes. Optical microscopy, XRD, SEM and TEM analysis were performed to observe the microstructures and to determine the structures of welded zone. In addition, mechanical properties were measured by the microhardness test, tensile test and Erichsen test to evaluate the formability of the welded specimen. There was no trapped Zn in the fusion zone, and the phases of this region consisted of polygonal ferrite, quasi-polygonal ferrite, banitic ferrite and martensite. The elongation value of welded specimen was more than 80% of the value in substrate metal, and the LDH value was more than 90% of the value in substrate metal.     

The nucleation of microcellular thermoplastic foam with additives: Part II: Experimental results and discussion

Experiments were performed to validate the model for the nucleation of microcellular foams in amorphous thermoplastic polymers. The polystyrene-zinc stearate system was chosen as the model system. Other additives such as stearic acid and carbon black were also investigated. Molecular weight and orientation effects were studied. Nitrogen and carbon dioxide were used to produce the microcellular bubbles. Results show that amounts of soluble additives at levels just below their solubility limit and high gas saturation pressures yield the most acceptable foams—ones with a large number of uniform small bubbles. In this region, the bubble number is sensitive to both the gas saturation pressure and the concentration of solutes. Increasing the concentration of soluble additives above the solubility limit has little effect on bubble number and almost eliminates the dependence on saturation pressure. Molecular weight and orientation had no effect on the number of bubbles produced. Similarly, carbon black, which is insoluble in and which bonds well to polystyrene, produced no effect on bubble numbers. The agreement between theoretical predictions and experimental results is reasonably good.