Modelling of cutting tool – soil interaction – part II: macromechanical model and upscaling

In the foregoing paper we have proposed a strategy for soil modelling based on the discrete approach. By considering the soil as an assembly of rigid disks we have developed a local model. The model concentrates at the contact level between the disks the real mechanical behaviour of the soil. For this purpose suitable contact models have been developed, where specific elasto-plastic laws have been implemented in the node-to-segment contact formulation.In this second part after investigating the mechanical behaviour of the local model we reproduce, with an assembly of disks (global model), the real behaviour of stiff soils and rocks under standard loading paths. The change of scale from the local to global level is carried out through dimensional analysis. The behaviour of different soils is simulated by regular and irregular monodisperse packings of disks and compared with real laboratory tests.     

Lipid autoxidation in fishery products postharvest: Is cold to freezing oxygen‐free packaged storage the better remedy?

The progress of lipid oxidation in fishery products is complex, as it involves a whole lot of reactions that deter product quality. On the other hand, the use of modified atmosphere packaging (MAP) has, over the years, been effective in improving food product safety and nutritional quality. In addition, as an oxygen‐free and protective food packaging technique, MAP has been shown to effectively minimize overall lipid damage. In this article we discuss how cold to freezing/sub zero‐temperatures could be promising for reducing the development of lipid oxidation in fishery products.     

AC electrical resistance measurements of PdHx samples versus composition x

Electrical and optical properties of SnO₂ film deposited on indium tin oxide substrate by dip coating have been investigated. The electrical conductivity of the SnO₂ film exhibits the extrinsic conductivity mechanism with two shallow and deep donor levels. The current voltage characteristics of SnO₂ film confirm the presence of space charge limited conduction. The density of states at the Fermi level N(E_F) for the SnO₂ film was determined using current–voltage characteristics and was found to be 1.63 × 10¹⁶ eV⁻¹ m⁻³. The Seebeck coefficient of the SnO₂ at room temperature indicates the n-type electrical conductivity. The Seebeck coefficient suggests that the electrical conductivity of the SnO₂ film varies from n-type conductivity to p-type conductivity with increasing temperature. The optical constants, such refractive index as dielectric constants, were determined from the reflectance, transmittance and absorption spectra. The refractive index dispersion behavior of the SnO₂ film obeys the single oscillator model. The fundamental absorption edge in SnO₂ film is formed by the direct allowed transitions with band gap of 3.40 eV.     

Will MCP-1 and RANTES take center stage in inflammatory diseases including asthma?

There were analyzed the conditions under which the basal glycemia and/or glucose tolerance curve is not contaminated by stress induced changes in glycide metabolism. When the basal glycemia was monitored, blood was sampled to heparinized capillaries from retrobulbar plexus under the light ether anaesthesia or by decapitation without narcosis. The animal represented the control for itself. No differences was found in basal glycemia under the two mentioned blood sampling. In the second series of experiments glycemia was monitored in the time schedule which is used in glucose tolerance test, i.e., blood sampling was performed 30, 60, 120 and 180 min after the first sampling from retrobulbar plexus either under light ether anaesthesia (in 14 h starvated rats or in rats with free access to diet) or under Nembutal anaesthesia (in 14 h starvated rats). No differences were found in glycemia when two types of narcosis is compared. No signs of augmentation were detected. In the last series when blood sampling was taken in two sec intervals, time dependent augmentation of stress glucose elevation was found. The augmentation was more expressed in the rats with free access to diet than in starvated animals.     

Diffused introduction of Organic Rankine Cycle for biomass‐based power generation in an industrial district: a systems analysis

Specific Organic Rankine Cycle (ORC) units dedicated to biomass‐based power production have recently been developed through the introduction of novel organic working media and technology innovation. For small systems, ORC technology appears as an efficient alternative to conventional generation if also process waste heat can be exploited, as resulted in the last few years from the successful operation of several demonstration plants in Austria and Switzerland. The present study aims to investigate the impact of the introduction of ORC units in an industrial context from a system perspective, with particular reference to industrial districts, which are characterized by the concentration in small areas of a large number of medium‐ and small‐sized firms. The paper focuses on the opportunity of combining ORCs, traditional Rankine cycles and multi‐source district heating to meet energy requirements in an industrial district in North Eastern Italy. To this end, a mixed‐integer linear programming model oriented to economical optimization of the system is developed and sensitivity analysis is carried out in order to determine the conditions for the expansion of biomass‐based power generation in the analyzed industrial district and to evaluate potential for CO₂ emission reduction. Copyright © 2004 John Wiley & Sons, Ltd.     

The direct effect of heavy ions and electrons on thymidine in the solid state

PURPOSE: To study the direct effect of heavy ions and electrons on thymidine. MATERIALS AND METHODS: The thymidine samples in the solid state were exposed to a beam of O7+ heavy ions with an energy of 10.6 MeV/u (LET approximately 500keV/microm) and to electrons of 2MeV (LET approximately 0.18keV/microm). The major decomposition products of thymidine were purified by high performance liquid chromatography (HPLC) and identified by extensive spectrometric measurements (UV, mass spectroscopy, 1H and 13C NMR). RESULTS: The main degradation products of thymidine were isolated and characterized. Reaction mechanisms, involving transient radical species, are proposed to explain the heavy ion-mediated formation of the modified products. Furthermore, a semi-quantitative comparison of the modifications induced within thymidine by the two types of radiations was performed. CONCLUSION: Several new radiation-induced thymidine decomposition products have been isolated and characterized. The comparison of the effects induced by heavy ions and electrons on thymidine in the solid state clearly indicates several significant differences in the mechanisms of action. A relative increase in the extent of the modifications of the sugar moiety with respect to those of the base is observed with the heavy ions by comparison with electrons.     

Polymer–Aptamer Hybrid Emulsion Templating Yields Bioresponsive Nanocapsules

This article describes the synthesis of a DNA–polymer, being the nucleotide sequence an aptamer selected in vitro to target specifically the immunoglobulin E (IgE) protein, an allergy biomarker. Subsequent to coupling to poly(2‐alkyl‐2‐oxazoline) with N‐Boc protected amino acid side chains, the resulting amphiphilic DNA–polymer hybrid composed of the water‐soluble DNA fragment grafted to the hydrophobic polymer segment can be regarded as a high molecular weight analogue of a surfactant. It is demonstrated that the copolymer–aptamer stabilizes efficiently submicrometer size oil‐in‐water and water‐in‐oil emulsions, by dynamic light scattering, microscopy, and reflectometry. Particularly interesting is that the aptamer remains functional after coupling to a polymer backbone, stabilization of the emulsion droplets, and locking of the structure subsequent to cross‐linking polymerization. The resulting nanocapsules still target specifically the IgE protein. The biological‐stimulus responsiveness of the structures is of high potential for future developments of carriers for sustained and targeted delivery.     

Effect of temporal variation,gender and size on cuticle polyphenol oxidase activity in deep-water rose shrimp (Parapenaeus longirostris)

Seasonal changes and physiological factors related to sex, size and spawning period may alter polyphenol oxidase (PPO) activity in crustacean decapods. Given the undesirable effects that the enzyme has on the marketability of shrimps, the cuticles of the valuable deep-water rose shrimp were examined. Monthly measurements of PPO activity in cuticles of juvenile and adult males and females were recorded for one year, along with sea-surface temperature (SST) and photoperiod. PPO activity was highest during late summer (August and September) and was lowest between February and March. The rate of enzyme activity in males was double that of females, when corrected for time period. Juvenile shrimp had the highest enzyme activity. Under the conditions tested, our results support that PPO assessment should take into account the sex and size as factors that potentially biasing in tissue enzyme distributions.     

Study of partially encased composite beams with innovative position of stud bolts

In this article, static behavior of three partially encased composite beams under flexural condition is investigated in the context of studying some alternative positions for the headed studs. Shear resistance between the I-shaped beam and the concrete was provided by headed studs in two positions: vertically welded on the bottom flange and horizontally welded on the faces of the web. Experimental results show that the headed studs provide the composite action and increase the bending strength. The most remarkable position seems to be the headed studs vertically welded on the bottom flange. An analytical method to estimate the bending capacity of the encased beams is also proposed, giving a good prediction of the experimental results