Three-dimensional elasto-plastic finite element analysis

Advances in technology and interest in limit state design have made the inclusion of non-linear effects, such as elasto-plastic behaviour, desirable in the analysis of many structures. Improvements in solution algorithms coupled with parallel developments in high speed digital computers have now made the practical solution of such problems possible. The paper presents numerical solutions to three-dimensional elasto-plastic problems illustrating the applicability of isoparametric elements and the order of computation times involved.     

Investigations of Activation Energy of Porous Silicon Oxidation Using Calorimetric Methods

The oxidation of porous silicon has been studied using differential scanning calorimeter. The oxidation was found to consist of two parts with different activation energies. This indicates the existence of two different reaction mechanism. The results from the hydrogen desorption measurements have been used to study the different oxidation behaviour of the n- and p⁺-type porous silicon. The results show that the dihydride structure dominates on the surface of the n-type porous silicon, contrary to p⁺-type porous silicon, where the monohydride is the major structure. Explanations of these features are discussed. Using the activation energy, the surface termination effects are investigated. The best improvement in the activation energy was observed in the sample, whose surface was partially stabilized by ammonium groups.     

Microbial growth in building material samples and occupants’ health in severely moisture‐damaged homes

There is no commonly approved approach to detect and quantify the health‐relevant microbial exposure in moisture‐damaged buildings. In 39 single‐family homes with severe moisture damage, we studied whether concentrations of viable microbes in building material samples are associated with health among 71 adults and 68 children, and assessed with symptoms questionnaires, exhaled NO, and peak expiratory flow (PEF) variability. Symptoms were grouped into three scores: upper respiratory symptoms, lower respiratory symptoms, and general symptoms. The homes were divided into three groups based on viable counts of fungi, actinomycetes, and total bacteria cultivated from building material samples. Highest group of actinomycete counts was associated with more general symptoms, worse perceived health, and higher daily PEF variability (aOR 12.51; 1.10‐141.90 as compared to the lowest group) among adults, and with an increase in lower respiratory symptoms in children, but the confidence intervals were wide. We observed significant associations of fungal counts and total microbial score with worse perceived health in adults. No associations with exhaled NO were observed.     

Comparing university students’ commitment – a multicultural case study

The aim of this research was to evaluate and compare the creative tension of university students in three different universities in South Korea and Finland. The creative tension, or the gap between a person's feeling of current reality and target for future, was analysed according to features describing their committing factors related to their universities and studies. Data for this study were collected from 41 university students through self-evaluation using internet-based survey instrument. The application was able to identify the creative tension in each group of university students, and the results show differences in creative tension across the universities and also between countries. This type of in-depth analysis into the cultural perceptions of attributes offers valuable new information for academia and businesses.     

On‐Chip Self‐Assembly of a Smart Hybrid Nanocomposite for Antitumoral Applications

A hybrid nanocomposite comprised by porous silicon nanoparticles and a stimuli responsive polymeric material, polyethylene glycol‐block‐poly(L‐histidine), is spontaneously formed by nanoprecipitation in a flow‐focusing microfluidic chip. The nanocomposite presents a novel hybrid compound micelle structure with a great robustness for therapeutic applications. Therefore, the nanocomposite is developed and tested as a “smart” multistage drug delivery system (MDDS) in response to some of the current problems that cancer treatment presents. Based on the stimuli‐responsive behavior of the nanocomposite, a chemotherapeutic agent is successfully loaded into the nanosystem and released upon changes in the pH‐values. The nanocomposite demonstrates enhanced stability in plasma, narrow size distribution, improved surface smoothness, and high cytocompatibility. Furthermore, the nanocomposite presents reduced nanoparticle internalization by phagocytic macrophage cells and pH‐dependent cell growth inhibition capacity. Overall, the developed hybrid nanocomposite shows very promising features for its further development as a “smart” pH‐responsive MDDS.     

Linoleic acid intake and susceptibility of very-low-density and low density lipoproteins to oxidation in men

Lipoprotein peroxidation is thought to play an important role in atherogenesis. In the Kuopio Atherosclerosis Prevention Study (KAPS) the intake of fat and fatty acids, the oxidation susceptibility of the plasma very-low-density + low-density lipoprotein (VLDL+LDL) fraction (by induction with copper or hemin and hydrogen peroxide), and concentrations of plasma antioxidants, serum lipids, and lipoproteins were measured in 393 men. In the multivariate-regression model dietary linoleic acid was the most important determinant of the maximal oxidation velocity for the hemin assay (standardized regression coefficient = 0.294, P<0.0001). In the copper assay the association of dietary linoleic acid and maximal oxidation velocity was second in order of strength (standardized regression coefficient = 0.324, P< 0.0001). We conclude that high linoleic acid intake is associated with increased oxidation susceptibility of atherogenic lipoproteins in men.     

The nature of white luminescence in SiO2:C layers

Silicon oxide layers containing incorporated carbon (SiO₂:C) have been obtained by sequential thermal carbonization/oxidation of porous silicon. The as-synthesized SiO₂:C layers exhibit intense white photoluminescence (PL). The characteristics of excitation, emission, and relaxation of the white luminescence in the SiO₂:C layers have been studied. It is established that the observed broad PL band in fact consists of at least two subbands with the maxima of intensity in the green and blue spectral regions. Based on the experimental data, a model of the PL excitation and radiative recombination in SiO₂:C layers is proposed and justified.     

Scintillation effects on total fade distributions forEarth-satellite links

Scintillation effects on the cumulative fade distributions for Earth-satellite links are considered. Two combination methods for scintillation and attenuation distributions are compared using filtered and unfiltered 11.2 GHz beacon measurements from Austin, TX, on a 5.8° elevation path. A combination method based on the assumption of independent scintillation and attenuation phenomena is proposed. Attenuation and total fade distributions at 19.8 and 29.7 GHz from Kirkkonummi, Finland, on a 12.7° elevation path, are presented for a summer period. The effects of attenuation and scintillation are also calculated using meteorological data from several radiosonde stations. The calculations show that the relative significance of the scintillation is smaller at frequencies from 20 to 50 GHz than at 12 GHz     

Ultrasonographic manifestations of carotid atherosclerosis and glucose intolerance in elderly eastern Finnish men

OBJECTIVE: To study the association of ultrasonographic manifestations of common carotid atherosclerosis with glucose intolerance in survivors of the cohort of men born in 1900-1919 in eastern Finland. RESEARCH DESIGN AND METHODS: Carotid ultrasonography was carried out for 182 men in 1989. Glucose tolerance status classified based on an oral glucose tolerance test in 1984 and 1989 surveys was used in both prospective and cross-sectional analyses. RESULTS: Carotid atherosclerosis was common in men aged 70-89 years. There was no significant difference in the maximal carotid intimal-medial thickness between diabetic and nondiabetic men and over different age-groups; it was 1.28, 1.33, and 1.36 mm in subjects with diabetes, impaired glucose tolerance, and normal glucose tolerance, respectively (P = 0.69). No association between the presence of a nonmineralized or a mineralized atherosclerotic lesion with diabetes was found. Fasting plasma insulin did not relate to ultrasonographically detectable atherosclerotic lesions. CONCLUSIONS: Hyperglycemia and hyperinsulinemia may not be main contributors to atherosclerosis in elderly men, partly because smoking is less common and total and LDL cholesterol concentrations are lower in diabetic men than in men with normal glucose tolerance.