Influence of elastic and plastic anisotropy on the flow behavior in a duplex stainless steel

The load partitioning between two phases in a cold-rolled duplex stainless steel has been experimentally studied in situ by X-ray diffraction, for different loading directions. It was found that the load partitioning between the two phases is dependent on the loading direction. For loading in the rolling direction, both phases deform plastically to the same degree, while more plastic deformation occurs in the austenitic phase during loading in the transverse direction. For loading in the 45-deg direction, more plastic deformation occurs in the ferritic phase. The strong crystallographic texture in the ferritic phase makes the material anisotropic, with a higher stiffness and yield strength in the transverse direction compared to the rolling direction. The measured texture was used as input to theoretical predictions of both elastic and plastic anisotropy. The plastic anisotropy was predicted by assuming intragranular slip as the main deformation mechanism. The predicted anisotropic material properties were then used in finite-element simulations to study the flow behavior of the material in different directions. The predicted flow behavior was found to be in good agreement with the experimentally observed load partitioning between the phases for loading in the rolling and transverse directions. However, the yield strength of the ferritic phase during loading in the 45-deg direction was found to be lower than what was predicted. The reason for this is the difference in slip characteristics in different sample directions, because of the morphological texture.     

Unit cell structure of crystal polytypes in InAs and InSb nanowires

The atomic distances in hexagonal polytypes of III-V compound semiconductors differ from the values expected from simply a change of the stacking sequence of (111) lattice planes. While these changes were difficult to quantify so far, we accurately determine the lattice parameters of zinc blende, wurtzite, and 4H polytypes for InAs and InSb nanowires, using X-ray diffraction and transmission electron microscopy. The results are compared to density functional theory calculations. Experiment and theory show that the occurrence of hexagonal bilayers tends to stretch the distances of atomic layers parallel to the c axis and to reduce the in-plane distances compared to those in zinc blende. The change of the lattice parameters scales linearly with the hexagonality of the polytype, defined as the fraction of bilayers with hexagonal character within one unit cell.     

Joule Heating Induced Nonlinear Behavior in?the?Phase-Separated System (La0.73Bi0.27)0.67Ca0.33MnO3

A conduction mechanism has been investigated in the phase-separated compound (La_0.73Bi_0.27)_0.67Ca_0.33MnO₃ at various temperatures below and above the ferromagnetic-paramagnetic (FM-PM) transition temperature T _c . When a high current density applied, a strong nonlinear behavior with negative differential resistance (NDR) was observed. The application of an external magnetic field inhibits the appearance of NDR. Usually, the experiments strongly suggest that the electric field has an important effect on the nonlinear conduction behavior of the sample. However, our experiment shows that, instead of the electric field effect (that is electroresistance), the observed nonlinear behavior results mainly from the Joule heating effect. Thus, we should exercise extreme caution when interpreting the nonlinear conduction behavior of the phase-separated system.     

Use of endospore-forming bacteria as an active oxygen scavenger in plastic packaging materials

The incorporation of active oxygen scavengers in polymer packaging materials is essential to allow packaging of oxidation sensitive products. Opposed to the currently available chemical oxygen scavengers, systems based upon natural and biological components could have advantages towards consumer perception and sustainability. A modelsystem for a new oxygen scavenging poly(ethylene terephthalate) (PET) bottle is proposed using an endospore-forming bacteria genus Bacillus amyloliquefaciens as the active ingredient. Spores were incorporated in poly(ethylene terephthalate, 1,4-cyclohexane dimethanol) (PETG), an amorphous PET copolymer having a considerable lower processing temperature and higher moisture absorption compared to PET. To asses spore viability after incorporation, a method was optimized to extract spores from PETG using a chloroform/water mixture. Samples were also analyzed using a Live/Dead BacLight Bacterial Viability kit. It was shown that endospores were able to survive incorporation in PETG at 210 °C. Incorporated spores could actively consume oxygen for minimum 15 days, after an activation period of 1–2 days at 30 °C under high humidity conditions.

Industrial relevance

The study describes a modelsystem for the use of incorporated spores genus Bacillus amyloliquefaciens as an active oxygen scavenger in PET multilayer bottles using PETG as the middle layer material. Industrially, oxygen scavengers using incorporated viable spores as the active compound could have advantages towards consumer perception, recyclability, safety, material compatibility, production costs, … compared to currently available chemical oxygen scavengers.     

Towards Integrated Molecular Electronic Devices: Characterization of Molecular Layer Integrity During Fabrication Processes

Reproducible carbon/molecule/Cu molecular junctions are made with high yield using diazonium reduction of aromatic molecules on carbon with direct evaporation of Cu as a top contact. This report investigates the stability of these devices in response to fabrication steps. Raman spectroscopy through a transparent support shows that direct deposition of Au or Cu causes little change in molecular layer structure, while Ti and Pt deposition cause significant damage to the molecules. AFM, Raman, and XPS examination of Au, Cu, and Ti devices after removal of deposited metal confirm that Cu and Au have minimal effects on molecular structure. However, the molecular layer is rougher after Au deposition, probably due to partial penetration of Au atoms into the molecular layer. Completed carbon/molecule/Cu devices can be heated to 250 °C without significant changes in electronic behaviour while nitroazobenzene molecular layers on carbon were unaffected by photolithography or by 5 min at 400 °C in vacuum. Completed devices could be sealed with parylene‐N, stabilizing them to aqueous etching solution. The stability of carbon/molecule/Cu junctions is due, in part, to the strong carbon–carbon bonding and aggressive nature of diazonium surface modification. The results significantly expand the range of processing variables compatible with molecular electronic junctions.     

Shelf-life of minimally processed cabbage treated with neutral electrolysed oxidising water and stored under equilibrium modified atmosphere

Minimally processed vegetables (MPV) have a short shelf-life. Neutral electrolysed oxidising water (NEW) is a novel decontamination method. The objective of this study was to test the potential of NEW to extend the shelf-life of a MPV, namely shredded cabbage. Samples of shredded cabbage were immersed in NEW containing 40 mg/L of free chlorine or tap water (control) up to 5 min, and then stored under equilibrium modified atmosphere at 4 degrees C and 7 degrees C. Proliferation of aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria and yeasts were studied during the shelf-life. Also pH and sensorial quality of the samples as well as O(2) and CO(2) composition of the headspace of the bags was evaluated. From the microbial groups, only psychrotrophic counts decreased significantly (P<0.05) due to the effect of NEW, but the counts in treated samples and controls were similar after 3 days of storage at 4 degrees C and 7 degrees C. Packaging configurations kept O(2) concentration around 5% and prevented CO(2) accumulation. pH increased from 6.1-6.2 to 6.4 during the shelf-life. No microbial parameter reached unacceptable counts after 14 days at 4 degrees C and 8 days of storage at 7 degrees C. The shelf-life of controls stored at 4 degrees C was limited to 9 days by overall visual quality (OVQ), while samples treated with NEW remained acceptable during the 14 days of the experiment. The shelf-life of controls stored at 7 degrees C was limited to 6 days by OVQ and browning, while that of samples treated with NEW were limited to 9 days by OVQ, browning and dryness. According to these results, a shelf-life extension of at least 5 days and 3 days in samples stored respectively at 4 degrees C and 7 degrees C can be achieved by treating shredded cabbage with NEW. NEW seems to be a promising method to prolong the shelf-life of MPV.     

SEPARATION AND QUANTIFICATION OF ALL MAIN HOP ACIDS IN DIFFERENT HOP CULTIVARS BY MICROEMULSION ELECTROKINETIC CHROMATOGRAPHY

Microemulsion electrokinetic chromatography has been applied to the analysis of hop acids in extracts of different hop cultivars. With this new analytical method, the 6 main hop bitter acids are completely separated within 10 minutes. Quantitative analyses of extracts from Saaz, Nugget and Wye Target cultivars have been compared to those obtained with reversed-phase high-performance liquid chromatography. The cohumulone and colupulone ratios are in good agreement. Microemulsion electrokinetic chromatography however is much faster and provides, in addition, data for the adhumulone and adlupulone ratios.     

Vauxhall’s post-industrial pleasure gardens: "death wish" and hedonism in 21st-century London

In recent years Vauxhall in south London has been transformed and rebranded as an urban leisure zone for gay men. Disused railway arches and warehouses have been converted into nightclubs and a significant night-time economy has developed rivalling Soho's existing gay village. However, with its commodified forms of public sex and high levels of recreational drug use, Vauxhall's club scene looks rather different from the British gay villages of the 1990s. This article examines how the area's nightlife entrepreneurs have capitalised on the recent liberalisation of licensing laws while drawing on the historical associations with the Vauxhall Pleasure Gardens (1660-1859) in attempts to market the area as a site of embedded hedonism. Overall, the aesthetic and cultural themes of Vauxhall's club scene seem to contradict earlier assumptions about the desexualisation and sanitisation of contemporary gay culture.     

Tunable wideband SAW-less receiver front-end in 65 nm CMOS

A surface acoustic wave-less receiver front-end for GSM, TD-LTE and TD-SCDMA standards featuring a novel low noise amplifier (LNA) architecture and harmonic rejection technique is presented. The two-stage LNA uses capacitive feedback in the first stage for wideband input matching. It can operate from 500 MHz up to 2.5 GHz with an S₁₁ below ?15 dB. The harmonic rejection mixer structure operates using two- and four-phase local oscillator signals and is capable of achieving a high harmonic rejection over a wide channel bandwidth. The average harmonic rejection is above 60 dB measured over a 20 MHz LTE channel and above 70 dB over a GSM channel. The mixer structure contains digitally tunable resistor and capacitor banks for precise tuning, causing the peak harmonic rejection in the channel to exceed 80 dB. The precise tuning capability ensures good harmonic rejection in the presence of process mismatch and duty cycle mismatch. The 1-dB received signal compression point with a blocker present at 20/80 MHz offset for low-/high-band is 0 and +2 dBm, respectively. In-band IIP3, and IIP2 are ?14.8 and >49 dBm, respectively, for low-band. For high-band they are ?18.2 and >44 dBm. Implemented in 65 nm CMOS, the complete front-end consumes 80 mW of power.