Intracellular disintegration by shockwave pretreatment accelerates “dry fermentation”

Dry fermentation refers to the process of anaerobic digestion that does not take place in a mixable liquid environment but in stacks loaded into airtight chambers. Since it is difficult for anaerobic consortia to decompose biomass without operating fluid, the process of dry fermentation is time consuming and considered technically inefficient. However, the construction costs of such biogas plants are significantly lower in comparison to conventional continuous technologies. Shockwave pretreatment is a modern method of intracellular disintegration that occurs purely on the basis of physical forces. It was confirmed for the first time that shockwaves are capable of accelerating methanogenesis, even in technologies that do not utilise a process liquid. This finding opens up new opportunities with regards to the processing of feedstock such as solid biowaste.     

Analytical Models of Thermal-Stress Induced Phenomena in Isotropic Multi-Particle-Matrix System

The paper presents four topics dealing with phenomena induced by elastic thermal stresses acting in an isotropic multi-particle-matrix system to represent a model system applicable to real multi-phase materials of a precipitation-matrix type. The isotropic multi-particle-matrix system consists of periodically distributed spherical particles in an infinite matrix to be imaginarily divided into cubic cells containing a central spherical particle. Formulae for the thermal stresses to be investigated within the cubic cell represents functions of the particle volume fraction v and the particle radius R. The thermal stresses originate during a cooling process as a consequence of the difference α _m  ? α _p in the thermal expansion coefficients α _m and α _p of the matrix and the particle, respectively. Additionally, such temperature range is considered within which the multi-particle-matrix system exhibits elastic deformations regarding the yield stress and the particle-matrix boundary adhesion strength. Analytical fracture mechanics to represent the first topic of this paper results from the determination of a curve integral of the thermal-stress induced elastic energy density. The curve elastic energy density results in the determination of the critical particle radii R _pc and R _mc as reasons of the crack initiation in the spherical particle and the matrix for α _m  ? α _p  < 0 and α _m  ? α _p  > 0, respectively. Consequently, the crack propagation to follow the crack initiation is a consequence of the particle radius R > R _qc (q = p, m). Finally, a shape of the crack in a plane perpendicular to the direction of the crack propagation in the particle (q = p) and the matrix (q = p) is described by the function f _q related to the ideal-brittle components. With regard to the crack initiation, the analytical determination of the radius R _qc is considered for any multi-phase materials of a precipitation-matrix type. With regard to the crack propagation, the analytical determination of the function f _q along with an analysis concerning the crack dimension and directions of the crack propagation is considered for ceramic multi-phase materials which are generally assumed to be ideal-brittle. The thermal stresses induce resistance against compressive or tensile mechanical loading for α _m  ? α _p  > 0 or α _m  ? α _p  < 0, respectively. The analytical determination of the resistance results from the elastic energy gradient to represent the second topic of this paper. Derived by two equivalent mathematical techniques, the gradient within the cubic cell is defined as a surface integral of the thermal-stress induced elastic energy density. Consequently the ‘surface’ elastic energy density results in the analytical determination of the system strengthening to represent the third topic of this paper. Representing the fourth topic of this paper, an analytical model of stresses originating in isotropic crystalline lattices are derived. The stresses in the lattices are a consequence of the presence of a central substitutive atom. Additionally, elastic energy, induced by the substitute atom and accumulated in the lattices, is also derived. Finally, readers can substitute numerical values of parameters of real multi-phase materials into the presented formulae.     

Rapid detection of genus Cronobacter in powdered infant formula milk

Rapid and specific detection of Cronobacter spp. in powdered infant formula milk (IFM) is of great importance for health and safety reasons. In the present study, two rapid and specific methods, the immunochromatographic strip (ICT) and the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), were tested for the detection of Cronobacter spp. in IFM. IFM samples spiked by Cronobacter spp. were correctly detected as positive by both methods. These results were verified by the classical cultivation microbiological method (ISO/TS 22964:2006). All three methods were used for the analyses of 13 IMF samples from a local market with identical results. Only one IFM sample was found to be positive. Both tested methods considerably reduced the total detection time, to 24?h (ICT) and 46?h (MALDI-TOF MS), whereas the reference ISO/TS 22964:2006 method needs 140?h.     

Fungal resistance and physical–mechanical properties of beech plywood having durable veneers or fungicides in surfaces

Improvement of insufficient fungal resistance of beech plywood for wet conditions was examined by: (1) incorporation of durable oak (Quercus robur) or black locust (Robinia pseudoacacia) surface veneers instead of beech (Fagus sylvatica) ones; (2) primordial treatment of beech surface veneers with 0.5, 1, 1.5 and 3 % solutions of fungicides DDAC, IPBC, Propiconazole and Tebuconazole; (3) additional treatment of beech plywood with the same fungicides. The anti-fungal efficiency of these three methods, applied to five-layer plywood boards glued with phenolic resin, was assessed either by decay test with two brown rot fungi (Coniophora puteana and Serpula lacrymans) and one white rot fungus (Trametes versicolor) using edge protected specimens according to modified ENV 12038, or by mould test with two microscopic fungi (Aspergillus niger and Penicillium brevi-compactum) according to modified EN 15457. The durability of beech plywood significantly increased after incorporation of black locust veneers into the surface layers, and also thanks to organic fungicides (0.5 % IPBC, Propiconazole or Tebuconazole, and 1.5 % DDAC) present in the surfaces. Other selected properties of beech plywood were sometimes influenced positively (e.g., soaking due to less permeable black locust and oak surface veneers) or negatively (e.g., shear strength due to fungicides).     

Capillary absorption in concrete and the Lucas–Washburn equation

Capillary absorption kinetics of concrete–ethylene glycol system was studied with respect to concrete matrix porosity and liquid viscosity. Porosity of specimens was altered by air-entraining agents and superplasticizers. Liquid which doesn’t react with cement gel was chosen for the experiment in order to study the reasons for deviation from Lucas–Washburn equation observed in concrete–water system. Viscosity of ethylene glycol changes from ～23 to 2 mPa s in the temperature range from 20 to 100 °C. The values of the capillary coefficient were determined at 20, 60 and 100 °C using Neutron Radiography and were found to be in the range from ～1.5 to 4.9 mm h^?1/2. The results show that the Lucas–Washburn equation in concrete–ethylene glycol system is valid only for ～25 h, which indicates that swelling and rehydration of cement gel are not the main reasons for deviation observed in concrete–water system.     

Career development in adolescence as a family project.

This study conceptualizes and investigates career-relevant parent–child conversations and other actions over time as a family project. Dyads composed of a parent and an adolescent from 20 families participated in a videotaped career-related conversation to determine a family career-development project that was subsequently monitored for a 6-month period and followed up with a 2nd videotaped conversation. On the basis of a systematic qualitative analysis, several dimensions were identified as facilitating the family career-development project, including joint goals, communication, goals-steps congruence, and individuation. These family career-development projects were organized as part of broader relationship, identity, parenting, and cultural projects that also played a decisive role in the success of the family career-development projects themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity

Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time.This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination.The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity.     

A note on finding minimum cuts in directed planar networks by parallel computations

We consider the problem of finding a maximum subset of a given set of wires connecting two rows of terminals with fixed positions, such that no wires in the subset cross. We derive an algorithm that runs in O(p + (n ? p) ? g(p + 1)) time, where n is the number of wires given and p is the maximum number of noncrossing wires; in many practically relevant cases, e.g., when p is very high, it needs only linear time. We show how an extension of the algorithm solves the more general problem, where the positions of some terminals have some flexibility, within the same time bound.     

Observation of Unconventional Dynamics of Domain Walls in Uniaxial Ferroelectric Lead Germanate

Application of scanning probe microscopy techniques such as piezoresponse force microscopy (PFM) opens the possibility to re‐visit the ferroelectrics previously studied by the macroscopic electrical testing methods and establish a link between their local nanoscale characteristics and integral response. The nanoscale PFM studies and phase field modeling of the static and dynamic behavior of the domain structure in the well‐known ferroelectric material lead germanate, Pb₅Ge₃O₁₁, are reported. Several unusual phenomena are revealed: 1) domain formation during the paraelectric‐to‐ferroelectric phase transition, which exhibits an atypical cooling rate dependence; 2) unexpected electrically induced formation of the oblate domains due to the preferential domain walls motion in the directions perpendicular to the polar axis, contrary to the typical domain growth behavior observed so far; 3) absence of the bound charges at the 180° head‐to‐head (H–H) and tail‐totail (T–T) domain walls, which typically exhibit a significant charge density in other ferroelectrics due to the polarization discontinuity. This strikingly different behavior is rationalized by the phase field modeling of the dynamics of uncharged H–H and T–T domain walls. The results provide a new insight into the emergent physics of the ferroelectric domain boundaries, revealing unusual properties not exhibited by conventional Ising‐type walls.     

Determination and correlation of axial-mixing parameters in an agitated liquid-liquid extraction column

Dispersion coefficients were measured in a pilot-plant sized agitated liquid-liquid extraction column of the Kuhni type. Available techniques were considered, and the axial mixing in both phases obtained over a broad range of operating conditions, both with and without mass transfer and with two sets of stator plates. Earlier correlations for backmixing in the continuous phase were checked and improved, the final equation being successfully tested on available published data.