Understanding the catalytic effects of H2S on CVD-growth of α-alumina: Thermodynamic gas-phase simulations and density functional theory

The catalytic effect of H₂S on the AlCl₃/H₂/CO₂/HCl chemical vapor deposition (CVD) process has been investigated on an atomistic scale. We apply a combined approach with thermodynamic modeling and density functional theory and show that H₂S acts as mediator for the oxygenation of the Al-surface which will in turn increase the growth rate of Al₂O₃. Furthermore we suggest surface terminations for the three investigated surfaces. The oxygen surface is found to be hydrogenated, in agreement with a number of previous works. The aluminum surfaces are Cl-terminated in the studied CVD-process. Furthermore, we find that the AlClO molecule is a reactive transition state molecule which interacts strongly with the aluminum and oxygen surfaces.     

Storage of grain in experimental silos functional principle,and reproducibility of results in simultaneous experiments and in experiments separated in time

The construction of experimental storage silos is described. Control of air humidity, temperature, air composition and quantity is possible with these: The influence of environmental factors on the life processes of cereal grain, microorganisms, and pests can be studied. Samples of the stored material can be taken during the experiment without disturbing the storage conditions The results of simultaneous experiments correspond well to those of experiments separated in time. The influence of environmental factors on microflora, germinating capacity and respiration is discussed. With the equipment here described it mil be possible to carry out reproducible storage experiments on seed, feedstuff, grain and vegetables etc., and to study the influence of exactly characterised changes in the environment on the keeping qualities of the stored material.     

Technical aspects of status and expected future trends for wind power in Denmark

The power system of Denmark is characterized by significant incorporation of wind power. Presently, more than 20% of the annual electricity consumption is covered by electricity‐producing wind turbines. The largest increase in grid‐incorporated wind power is expected to come from large (offshore) wind farms operating as large wind power plants with ride‐through solutions, connected to the high‐voltage transmission system and providing ancillary services to the system. In Denmark there are presently two offshore wind farms connected to the transmission system: Horns Rev A (160MW rated power in the western part of the country) and Nysted (165MW rated power at Rødsand in Eastern Denmark). The construction of two more offshore wind farms, totalling 400MW by the years 2008–2010, has been announced. This article presents the status, perspectives and technical challenges for wind power in the power system from the point of view of Energinet.dk, Transmission System Operator of Denmark. Copyright © 2006 John Wiley &Sons, Ltd     

On the hydrogenation mechanism in magnesium I

The first time hydriding of spherical magnesium particles covered by a thin oxide layer and sieve-fractionated into narrow size distributions within the range 40–90 μm was followed by microgravimetry. The size distributions of the fractions were determined by semiautomatic image analysis. The hydridings were run at 402°C and 3 MPa hydrogen pressure after heating in helium. A dependence of the rate of hydriding on the heat treatment prior to reaction was observed and it is proposed that the heat treatment causes oxygen atoms to diffuse into the bulk metal and thereby break up the protective oxide layer. Based on the observed hydride propagation in the metal particles, a statistical model for the hydriding of a particle is applied to the hydriding curves for a series of samples. The data are found to be in fine agreement with the proposed model. It is concluded that care must be taken when generalizing results from the hydriding of magnesium powders.     

Sudan Red G as an adulterant in turmeric (Curcuma longa L.)

Zusammenfassung Eine rote Substanz wurde aus einer tanzanianischen Gelbwurzelprobe (Curcuma Tonga L.) isoliert und durch Röntgen-Einkristall-Analyse als Azofarbstoff Sudanrot G (1-(2-Methoxyphenylazo)-2-naphthol) identifiziert. Die Konzentration des Pigments in der Droge war 0,09%, aus UV-spektroskopischen Daten berechnet.

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Sudan Red G as an adulterant in turmeric (Curcuma longa L.)

Summary A red substance was isolated from a Tanzanian sample of turmeric (Curcuma longa L.) and identified by X-ray single crystal analysis as the azo dye Sudan Red G (1-(2-methoxyphenylazo)-2-naphthol). The concentration of the dye in the spice was 0.09%, as calculated from the UV spectrum.

     

An evaluation of the effect of catalase and 3,3-thiodipropionic acid on the recovery of freeze-injured coliform bacteria

Coliform bacteria isolated from ground beef were frozen in 0.1 M phosphate buffer at ?18°C for 72 h. Before and after freezing, colony counts were made in tryptic soy agar (TSA) (Difco) and in TSA supplemented with 680 units of catalase ml^? and 1% 3,3-thiodipropionic acid (TDPA), respectively. The two H₂O₂ scavengers exerted no enhancing effect on cell recovery in the non-selective medium.Catalase and TDPA were also added to the TSA bottom layer in the selective dual-plating repair detection procedure described by Ray and Speck [(1978) Appl. Environ. Microbiol. 35, 883–885] using violet red bile agar (VRBA) as the selective medium. After freezing, approximately 70% of surviving cells could be recovered using TSA and TSA supplemented with catalase or TDPA (TSAC, TSAT).A total of 19 samples of various frozen food products (ice cream, pastries, ground meat and vegetables) were examined for coliform bacteria by the repair detection procedure with unsupplemented TSA and TSA with catalase or TDPA. Coliforms were detected in 15 samples. The logarithmic mean colony count with the TSA/VRBA procedure was 1350 g^?1. With TSAC/VRBA and TSAT/VRBA the counts were 1590 and 1400 g^?, respectively. These counts did not differ significantly from those obtained with unsupplemented TSA/VRBA (P>0.05).     

Genetic determination of mortality rate in Danish dairy cows: A multivariate competing risk analysis based on the number of survived lactations

Dairy cow mortality has been steadily increasing during the last 2 decades in Denmark. This study aims to verify whether genetic mechanisms might be contributing to this increase. To do so, the records of 880,480 Holstein, 142,306 Jersey, and 85,206 Red Danish dairy cows calving from 1990 to 2006 were retrieved from the Danish Cattle register. Two causes of culling of cows were considered: death and slaughtering. Bivariate competing risk genetic models with a sire model structure were used to describe the death and the slaughtering rates simultaneously. The models included 2 random components: a sire random component with pedigree representing the sire genetic effects and a herd-year-season component. Moreover, the level of heterozygosity and the sire breed proportions were included in the models as covariates to account for potential nonadditive genetic effects due to the massive introduction of genetic material from other populations. The correlations between the sire components for death rate and slaughter rate were negative and small for the 3 populations, suggesting the existence of specific genetic mechanisms for each culling reason and common concurrent genetic mechanisms. In the Holstein population, the effects of the changes in the level of heterozygosity, breed composition, and the increasing genetic trend acted in the same direction, increasing the death rate in recent years. In the Jersey population, the effects of the level of heterozygosity and the breed proportion were small, and only the increasing genetic trend can be pointed as a genetic cause to the observed increase in the mortality rate. In the Red Danish population, neither the time-development pattern of the genetic trend nor the changes in the level of heterozygosity and breed composition could be causing the observed increase in the mortality; thus, nongenetic factors must be causing this negative development.     

Short communication: Born to be a loser cow?

Over the last few years, an increasing awareness has arisen in Denmark of the existence of cows with a generally lowered health and production status, referred to as “loser cows.” A previous study has estimated that the overall prevalence of loser cows in Danish Holstein herds is 3.2%. The aim of this study was to estimate genetic and phenotypic parameters for the loser cow state and the underlying traits: lameness, hock lesions, other cutaneous lesions, and condition of hair coat. Records on 6,098 cows were analyzed with an animal model including fixed effects of herd, season of scoring and location of scoring, age at first calving, lactation stage, and parity in addition to additive genetic effects and permanent environmental effects. The heritability of the loser cow score was 0.08 and for the underlying traits the heritability ranged from 0.05 to 0.12. The genetic correlations between various pairs of traits included in the loser cow score ranged from 0.04 to 0.68 and the phenotypic correlations ranged from 0.09 to 0.21. The genetic and phenotypic correlations between the loser cow score and the underlying traits ranged from 0.25 to 0.89 and 0.20 to 0.85, respectively, supporting the concept of the loser cow score. The traits included in the loser cow score are easy to assess and all showed genetic variation. They are therefore suitable for inclusion in a total merit index aimed at breeding for more robust cows.     

On design of joint positions for minimum mass 3D frames

An iterative procedure for determining the joint positions and dimensions of cross-sections corresponding to a minimum mass space frame is presented. Stress constraints, displacement constraints and side constraints are taken into account, with the possibility for linking of the design variables, which in addition to the joint positions are the beam dimensions. The frame is assumed to carry consecutively a number of different systems of loads, including temperature loads and weights. The stressed state analysis includes tension, bending, shear and torsion of the beam elements. The optimization iteration includes a sequence of quadratic programming problems with the possibility of move-limits. Only “nearby” constraints (active strategy) are considered, and analytical expressions for the gradients are derived. Illustrative medium scale problems are presented.     

Efficacy of standard glucose-based and reduced-osmolarity maltodextrin-based oral rehydration solutions: effect of sugar malabsorption

Previously we reported that standard oral rehydration salts (ORS) solution is not as effective as a reduced-osmolarity glucose-based ORS for the treatment of children with acute noncholera diarrhoea: with standard ORS the diarrhoea lasts longer, stool output is greater, serum sodium is higher, and there is more need for supplemental intravenous infusion. We studied a reduced-osmolarity maltodextrin (MD)-based ORS to determine whether it had similar benefits, and also the effect of sugar malabsorption on the efficacy of standard and MD-based ORS. A total of 90 boys aged 3-24 months with acute noncholera diarrhoea and moderate dehydration were randomly assigned to either standard ORS (glucose 20 g/l, osmolarity 311 mmol/l) or MD-ORS (MD 50 g/l, osmolarity 227 mmol/l). There were no differences in treatment results. Some 46% of subjects had a high total stool output (> 300 g/kg), which was unrelated to the type of ORS given. High stool output was significantly associated with a longer duration of diarrhoea (33 vs. 15 hours; P < 0.001), a persistently elevated serum sodium (149 vs. 144 mmol/l at 24 h; P < 0.02), the need for intravenous infusion (11/41 vs. 0/48; P < 0.002), and an increase in faecal reducing substances (10.8 vs. 3.4 g/l at 24 h; P < 0.001). We conclude that some children given standard ORS develop osmotic diarrhoea owing to the combined effect of transient sugar malabsorption and slight hypertonicity of the ORS. Earlier studies show that this adverse outcome can largely be avoided when extra water is given in reduced-osmolarity glucose-based ORS. Reduced osmolarity has no benefit, however, when glucose is replaced by maltodextrin, probably because the sugars released by hydrolysis of MD, when malabsorbed, raise the intraluminal osmolarity to equal or exceed that of standard ORS. Thus, reduced-osmolarity glucose-based ORS is superior to both standard ORS and reduced-osmolarity solutions based on maltodextrin and probably other complex carbohydrates. Studies are in progress to define the optimal formulation of reduced-osmolarity glucose-based ORS.