Bonding of densified beech wood using adhesives based on thermally modified soy proteins

The bondability/glueability of aged and sanded thermo-hydro-mechanically (THM) densified beech wood (Fagus sylvatica L.) was tested and compared with undensified sanded beech wood as a control. THM and control specimens were bonded with five different soy protein isolate (SPI) based adhesives. Commercial SPI powder was thermally modified in the vacuum chamber at 50 or 100?°C and pH adjusted (to pH 10.0) dispersions in water prepared at 24, 50 or 90?°C. Wettability was determined with measuring the sessile drop contact angles of water. Effective penetrations (EPs) and tensile shear strengths of THM and control specimens were determined. THM and control wood had similar wettability. Although THM wood had lower moisture content than control wood, it absorbed the water more slowly than control wood. THM specimens showed lower EPs than control specimens when comparing individual adhesives due to increased density of THM wood. Adhesives prepared with SPI thermally modified at 50?°C showed statistically significantly lower tensile shear strength of bonded THM specimens than that of bonded control specimens. THM densification had no significant effect on the bonding strengths of adhesives prepared with non-modified SPI and SPI thermally modified at 100?°C.     

Transverse compression behavior of Douglas-fir (Pseudotsuga menziesii) in saturated steam environment

The transverse compression behavior of Douglas-fir wood (Pseudotsuga menziesii) at high temperature (170 °C) and saturated steam conditions was studied and compared with previously reported compression behavior of hybrid poplar (Populus deltoides × Populus trichocarpa). The effect of the compression on the stress–strain response, non-linear strain function, and relative density change was examined by a modified Hooke’s law based on the load-compression behavior of flexible foams. Transverse compressive loading followed a typical stress–strain curve of wood. The compressive modulus of Douglas-fir was higher than hybrid poplar. The yield stress of Douglas-fir specimens was higher than yield stress of hybrid poplar specimens, while densification stress of both wood species was the same. The comparison of the non-linear strain function of Douglas-fir and hybrid poplar specimens revealed significant differences. The observed differences are assumed to be due to different cellular structure and chemical composition of softwoods versus hardwoods.     

Kinetics of resuscitation and growth of L. monocytogenes as a tool to select appropriate enrichment conditions as a prior step to rapid detection methods

Rapid methods still rely on a prior (shortened) enrichment step before application. Quantitative information is a prerequisite for understanding the resuscitation kinetics of the growth during the enrichment step. In this study various basal and newly introduced selective enrichment broths were evaluated. First, growth parameters (λ, μ_max) of both healthy and sub-lethally injured cells were determined. Next, a selection of enrichment broths was compared for their capacity to support detection within 24 h of low numbers of Listeria monocytogenes in artificially and naturally contaminated food samples. Detection was performed either by phage protein-based capture (Listeria Capture kit, Profos, Regensburg, Germany) combined with plating on chromogenic medium or by fluorescence in situ hybridization (FISH) using the VIT-Listeria kit (Vermicon, Munich, Germany). Kinetics of resuscitation and growth of L. monocytogenes in various enrichment broths showed that for detection of low numbers of sub-lethally injured L. monocytogenes cells at least an overnight enrichment was needed. A selective enrichment broth was needed to enable proliferation of L. monocytogenes within the indigenous bacterial flora present in foods. However, combination of an appropriate enrichment condition with advanced detection techniques may enable a 24 h detection of L. monocytogenes.     

Optical spectroscopy study of nc-Si-based p–i–n solar cells

In the present study we analyzed nanocrystalline silicon (nc-Si)-based p–i–n thin film structures (SiC/nc-Si/n-doped amorphous Si) on glass produced by radio-frequency plasma-enhanced chemical vapor deposition. The crystallinity of the nc-Si layer was modified by varying the deposition conditions ([SiH₄]/[H₂] ratio in the plasma and radio-frequency power). Structural properties of the samples (crystalline fraction and crystal size distribution) were inferred by Raman spectroscopy. Different optical spectroscopy methods were combined for the determination of the optical constants in different spectral ranges: spectrophotometry, ellipsometry and photothermal deflection spectroscopy. Characterization results evidence that the optical properties of the nc-Si layers are strongly connected with the layer structural properties. Thus, the correlation between density of defects, Urbach energy, band-gap and line-shape of dielectric function critical points with the crystalline properties of the films is established.     

Effects of CO2 on the resuscitation of Listeria monocytogenes injured by various bactericidal treatments

To assure the microbiological safety and quality of a food product, a combination of preservation hurdles is often used. Therefore, the effects of carbon dioxide at concentrations of 0, 20, 40 and 60% in modified atmospheres on the resuscitation of Listeria monocytogenes cells injured by mild bactericidal treatments during storage at 7 degrees C were examined. The bactericidal treatments were intense light pulses (ILP), chlorine dioxide (ClO(2)), lactic acid (LA) and heat. The results indicated additional bactericidal effects of CO(2) on cultures treated with LA, ClO(2) and ILP, with additional reductions in viable L. monocytogenes of 0.5-1.0 log cfu/ml. Lag phase duration was significantly different between the different treatments, with non-treated cells having the shortest lag phase, followed by that of heat, intense light pulses, lactic acid and finally ClO(2) treated cells. Maximum growth rate was also estimated and results showed a negative correlation with increasing CO(2) concentrations. A relationship was found between the amount of sub-lethally damaged cells after a mild inactivation treatment and the lag phase duration in the CO(2) environment. Current findings demonstrate the possibility that combining mild decontamination treatments and packaging in a CO(2) enriched environment could reduce the risk of L. monocytogenes infections in food due to an extension of the lag phase.     

Experimental investigation and thermodynamic prediction of the Ni-Pb-Sb phase diagram

The phase diagram of the ternary Ni-Pb-Sb system was investigated experimentally by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) methods, and predicted using the calculation of phase diagrams (CALPHAD) method. The phase transition temperatures of alloys along three predicted vertical sections of the Ni-Pb-Sb ternary system, with molar ratio Ni:Sb=1:3, Ni:Pb=1, and x(Sb)=0.6, were measured by DSC. The predicted isothermal section at 700 °C was compared with the results of the SEM-EDS analysis in this work.     

Sympathetic pupillary tone in old age

In an attempt to determine whether autonomic neural factors might be involved in senile miosis, we tested pupillary responses to agents acting on the ocular sympathetic system in old subjects and compared them to responses in young adults. Our results suggest that sympathetic tone is decreased in the elderly. The dilator pupillae muscle does not lose its sensitivity to norepinephrine with age.     

Integration of solar thermal energy into processes with heat demand

An integration of solar thermal energy can reduce the utility cost and the environmental impact. A proper integration of solar thermal energy is required in order to achieve it. The objective of this study is to maximise the solar thermal energy delivered to the process. It is a result of trade-off between the captured solar thermal energy and maximal energy delivered to the process (process demand). Two novel curves are introduced to present this trade-off: (i) The Captured Solar Energy Curve (CSEC), which represents the available amount of heat from solar source and (ii) The Minimal Capture Temperature Curve (MCTC), indicating the minimal temperature making the heat transfer feasible. The crossing point of these two curves presents the minimal temperature of the capture being still sufficiently high to be usable for processes. The suitability of these curves for using in combination with standard heat integration methods is analysed and evaluated. The capture potential is revealed in full when the CSEC and MCTC are used with the Grand Composite Curve. In Total Site Profiles, the heat recovery is first maximised and then the CSEC and MCTC tool is applied. The implementation of CSEC and MCTC approach is illustrated by two case studies.