On the formation of porosity and microchannels in growing scales

It is well known that oxide scales develop porosity and microchannels that permit inward transport of molecular species from the ambient gas even under conditions when there is no evidence of cracking of the scales. It is proposed that such porosity and microchannels develop as a result of grain growth and of plastic deformation (grain-boundary sliding, diffusion creep, etc.) under compressive stresses in the scales. The presence of small amounts of impurities enriched at grain boundaries in the scales may greatly affect deformation and mechanical and transport properties in scales.     

Simplified Large‐Area Manufacturing of Organic Electrochemical Transistors Combining Printing and a Self‐Aligning Laser Ablation Step

A hybrid manufacturing approach for organic electrochemical transistors (OECTs) on flexible substrates is reported. The technology is based on conventional and digital printing (screen and inkjet printing), laser processing, and post‐press technologies. A careful selection of the conductive, dielectric, and semiconductor materials with respect to their optical properties enables a self‐aligning pattern formation which results in a significant reduction of the usual registration problems during manufacturing. For the prototype OECTs, based on this technology, on/off ratios up to 600 and switching times of 100 milliseconds at gate voltages in the range of 1 V were obtained.     

Distribution of insoluble bound phenolic acids in barley grain

Insoluble bound phenolic acids were analysed by g.l.c. and by h.p.l.c. in eight abraded fractions of barley grain. Vanillic, p-coumaric, ferulic and diferulic acids were identified in all the fractions. Ferulic and p-coumaric acids were quantitatively the most important. The outer layers, comprising husks, pericarp, testa and aleurone cells, contained the highest concentrations of total phenolic acids (0.6–0.9%) while their concentrations were considerably lower in the endosperm layers (0.1% or less). Calculated on the basis of the cell wall content in the fractions, the highest concentration of ferulic acid was found in fractions enriched with aleurone cells while the highest concentration of p-coumaric acid was found in fractions containing high levels of husks.     

Antioxidative activity of summer savory (Satureja hortensis L.) and rosemary (Rosmarinus officinalis L.) in minced, cooked pork meat

The sensory intensity measured as theabsolute threshold value of spice andrecognition of spice was evaluated for summer savory and rosemary in meat balls. The values forabsolute threshold value of spice were found to be significantly lower for rosemary than for summer savory. The antioxidative activity of the spices was analysed in two accelerated model systems and in a storage experiment. In one of the model systems, oxidation was accelerated by heat and by an elevated pressure of oxygen. Both spices significantly improved the oxidative stability of the meat balls in this model system. In the second model system metal catalyst oxidation in a meat slurry was used and a reduction in the oxidative processes in samples containing the spices was again shown. In both model systems a slightly higher antioxidative activity was seen for rosemary compared to summer savory. In the storage experiment, the spices were added at a sensorially acceptable level and the heat-treated meat balls were stored at 5°C. A significant reduction in the development of warmed-over flavour (WOF) caused by the addition of spices was measured by a reduction in 2-thiobarbituricacid-reactivesubstances (TBARS) and in hexanal. A reduction in TBARS of approximately 30% in meat balls containing added spices was seen independently of packaging in 1% oxygen or in atmospheric air and the reduction (30%) was constant throughout the storage period.     

Timber-framed partition walls and their restraining effect on warp in built-in wall studs – Models for twist

The shape of timber changes due to variations in moisture content (MC). Analytical models, which explain how the cladding restrains the timber studs that are prone to twist, are presented. The models are used for parametric studies of various properties, such as longitudinal shrinkage, torsional modulus of elasticity and cross-sectional size of the timber stud and stiffness of the cladding. With respect to twist, the bending stiffness of the cladding is of great importance. Large bending stiffness increases the restraint in the twist-prone studs and results in a straighter wall. Low torsional stiffness in the studs makes it easier for the cladding to restrain twist.     

Aflatoxin contamination of consumer milk caused by contaminated rice by‐products in compound cattle feed

BACKGROUND: Elevated levels of aflatoxin M1 were observed in routine checks of consumer milk in southern Sweden in early 2006. A trace‐back study revealed contaminated milk from several farms, and a total of 68 farms were banned from delivering milk to dairies for shorter or longer periods. The maximum level of aflatoxin M1 in a single sample from an individual farm was 257 ng kg^?1 fresh milk. RESULTS: Aflatoxin analyses of commercial compound feed revealed that the contamination originated from the ingredient rice feed meal, a by‐product from the preparation of Basmati rice for human consumption. Up to 56 µg kg^?1 of aflatoxin B1 was found in rice feed meal at one feed mill. CONCLUSION: The present example shows that an aflatoxin‐contaminated minor feed ingredient included at less than 10% (w/w) of compound cattle feed can significantly contaminate the milk produced. This emphasises the need for effective monitoring of the feed chain of food‐producing animals in order to prevent food contamination. Copyright © 2008 Society of Chemical Industry     

Dielectric mismatch effect on coupled impurity states in a freestanding nanowire

We studied the coupled impurity states in a freestanding semiconductor nanowire (NW), within the effective mass approximation and including the effect of the dielectric mismatch, by using finite element method. Bonding and anti-bonding states are found and their energies converge with increasing distance d_i between the two impurities. The dependence of the binding energy on the wire radius R and the distance d_i between the two impurities is investigated, and we compare it with the result of a freestanding NW that contains a single impurity.     

Timber-framed partition walls and their restraining effect on warp in built-in wall studs – A model for spring

The shape of timber changes due to variations in moisture content (MC). A poor way of designing and/or erecting a structure may result in excessive deformation. An analytical model, which explains spring in a partition wall, is presented. The model is used for parametric studies of various properties such as longitudinal shrinkage coefficient, modulus of elasticity and cross-sectional size of the timber studs and stiffness of the cladding. With respect to spring, a problem is likely to occur when erecting a wall with single-sided cladding in a drying climate and the structure will benefit from relatively stiff studs and weak cladding.     

Development of a non-destructive micro-analytical method for stable carbon isotope analysis of transmission electron microscope (TEM) samples

The biogenicity of ancient morphological microfossil-like objects can be established by linking morphological (e.g. cell remnants and extracellular polymeric matrix) and chemical (e.g. isotopes, biomarkers and biominerals) evidence indicative of microorganisms or microbial activity. We have developed a non-destructive micro-analytical ion beam system capable of measuring with high spatial resolution the stable carbon isotope ratios of thin samples used for transmission electron microscopy. The technique is based on elastic scattering of alpha particles with an energy of 2.751 MeV. At this energy the ¹³C cross section is enhanced relative to the pure Rutherford cross section for ¹³C, whereas the ¹²C cross section is reduced relative to its pure Rutherford cross section. Here we report the initial results of this experimental approach used to characterize ultramicrotomed sections of sulfur-embedded graphite and microbial cells.