Plasma modification of polylactic acid in a medium pressure DBD

In this paper, a dielectric barrier discharge (DBD) operating in different atmospheres (air, nitrogen, helium and argon) and at medium pressure is employed to modify the surface properties of polylactic acid (PLA). Chemical and physical changes on the plasma-treated surfaces are examined using contact angle, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements. Results show that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: air and argon plasmas introduce oxygen-containing groups, while nitrogen discharges add nitrogen groups to the PLA surface. Quite surprisingly, also helium plasmas incorporate a small amount of nitrogen-containing functionalities: this observation can however be explained by the fact that the helium discharge operates in the glow mode. In the near future, it will be examined whether the performed plasma treatments can enhance PLA cell attachment and proliferation, which might open the door to many interesting biomedical applications.     

Impact of whole-building hygrothermal modelling on the assessment of indoor climate in a library building

This paper focuses on the importance of accurately modelling the hygrothermal interaction between the building and its hygroscopic content for the assessment of the indoor climate. Libraries contain a large amount of stored books which require a stable relative humidity to guarantee their preservation. On the other hand, visitors and staff must be comfortable with the indoor climate.     

Kirkendall Void Formation During Selective Oxidation

The selective oxidation of high Mn austenitic steel was investigated by transmission electron microscopy. The annealing resulted in a MnO surface layer and a Mn-depleted ferritic layer. At the MnO/steel interface, voids were formed between the a-xMnO.SiO₂ and c-MnO.Al₂O₃ layers. This is the first time that void formation is observed during selective oxidation of steel. The Kirkendall voids grow and develop characteristic void surfaces because of the fast diffusion of MnO on the void surface.     

A new technique for the calculation and 3D visualisation of magnetic complexities on solar satellite images

In this paper, we introduce two novel models for processing real-life satellite images to quantify and then visualise their magnetic structures in 3D. We believe this multidisciplinary work is a real convergence between image processing, 3D visualisation and solar physics. The first model aims to calculate the value of the magnetic complexity in active regions and the solar disk. A series of experiments are carried out using this model and a relationship has been indentified between the calculated magnetic complexity values and solar flare events. The second model aims to visualise the calculated magnetic complexities in 3D colour maps in order to identify the locations of eruptive regions on the Sun. Both models demonstrate promising results and they can be potentially used in the fields of solar imaging, space weather and solar flare prediction and forecasting.     

Evaluative conditioning in humans: A meta-analysis.

This article presents a meta-analysis of research on evaluative conditioning (EC), defined as a change in the liking of a stimulus (conditioned stimulus; CS) that results from pairing that stimulus with other positive or negative stimuli (unconditioned stimulus; US). Across a total of 214 studies included in the main sample, the mean EC effect was d = .52, with a 95% confidence interval of .466–.582. As estimated from a random-effects model, about 70% of the variance in effect sizes were attributable to true systematic variation rather than sampling error. Moderator analyses were conducted to partially explain this variation, both as a function of concrete aspects of the procedural implementation and as a function of the abstract aspects of the relation between CS and US. Among a range of other findings, EC effects were stronger for high than for low contingency awareness, for supraliminal than for subliminal US presentation, for postacquisition than for postextinction effects, and for self-report than for implicit measures. These findings are discussed with regard to the procedural boundary conditions of EC and theoretical accounts about the mental processes underlying EC. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of mammary stromal remodeling during the dry period

During the dry period between successive lactations, the mammary gland of dairy cows undergoes extensive remodeling that is marked by phases of involution and mammogenesis. Changes in the mammary epithelium during the dry period have been well characterized; however, few studies have examined the changes that occur in stromal tissue. The objective of this study was to characterize changes that occur in mammary stroma during the dry period. Mammary biopsies were taken from 9 multigravid Holstein cows in late lactation, at 1 wk after dry-off, 3 wk before expected calving date, and 1 wk before expected calving date. Tissue was fixed in formalin, embedded in paraffin, and cut into 5-μm sections. Sections were stained with hematoxylin and eosin or with immunohistochemistry for expression of smooth muscle α actin (SMA), fibronectin, stromelysin-1 (MMP-3), transforming growth factor-β1 (TGF-β1), and TGF-β receptor 2 (TGF-βR2). Images of tissues were captured with light microscopy, and imaging software was used to measure intralobular stromal area, number of activated fibroblasts, as identified by expression of SMA, and percentage of intralobular stromal area expressing fibronectin, MMP3, TGF-β1, and TGF-βR2. Analyses of variance were conducted and statistical differences were based on the least squares means of biopsy stage. Number of activated fibroblasts was greater at 1 wk dry than at 1 wk before calving (2,720 vs. 1,800 cells/mm²), percentage intralobular stromal area was greater at 1 wk dry (32%) and 3 wk before calving (37%) than at 1 wk before calving (25%), and TGF-β1 expression decreased 15% from late lactation to the dry period. The percentages of stromal area expressing fibronectin, MMP-3, and TGF-βR2 and the percentage of myofibroblasts were not different across biopsy stages. These results support the concept that stromal expression of transforming growth factor-β1 and fibroblast proliferation may be important for remodeling during the dry period.     

Influence of carbonate intercalation in the surface-charging behavior of Zn–Cr layered double hydroxides

The influence of interlayer composition in the surface charge and reactivity of layered double hydroxides (LDHs) has been explored. With this purpose, a chloride-intercalated Zn–Cr-LDH has been synthesized by the constant pH coprecipitation method and afterwards exchanged with carbonate to obtain solids with different Cl^?/CO₃^2? ratios. The solids structure has been characterized by elemental chemical analysis, powder X-ray diffraction and infrared spectroscopy, while its surface-charging behavior and reactivity have been studied by acid–base potentiometric titrations and electrophoretic mobility determinations. The chloride-intercalated sample shows an increasing hydroxyl adsorption with increasing pH and decreasing support electrolyte concentration and the particles present positive electrophoretic mobility in the measured pH range. As carbonate content increases in the samples, the total OH^? uptake diminishes and the samples show an isoelectric point at pH around 10. When the gallery is totally occupied by carbonate anions, the OH uptake vs. pH curves registered at different electrolyte concentrations merge at around pH 10. A LDH–water interface model has been used to give an interpretation to the experimental data. The model indicates that as carbonate content increases, the sample behavior becomes similar to that of a metal (hydr)oxide and that surface (bi)carbonate anions undergo acid–base reactions.     

Cyclic bond behaviour of plain bars. Part I: Experimental investigation

In recent years there has been wide use of non-linear dynamic analysis for the evaluation of existing structures in areas of high seismic risk. In the simulation of the cyclic behaviour of elements in reinforced concrete (RC) its bonding performance cannot be ignored. There are numerous numerical models developed in recent decades which can explicitly account for the slip between reinforcing bars and the surrounding concrete through the definition of the local hysteretic bond–slip relationship. As for plain bars, commonly used in reinforced concrete buildings before the 1970s, there are almost no references to hysteretic bond mechanisms.This paper describes the results of a series of monotonic and cyclic pull-out tests aimed at the assessment of the bond performances of plain round bars. Monotonic behaviour is characterized by a first ascending branch, up to the maximum bond strength; in this phase, as the slip increases, chemical–physical adhesion and micro-interlocking between the cement paste and the indentations of the bar surface progressively activate. During post-peak phase the only frictional contribute is present, gradually degrading towards a minimum value as the slip increases. The two parameters, maximum bond strength and minimum frictional bond, in spite of the high variability shown, seem to reflect well the literature indications about bond performances of plain bars. In cyclic field, where the only frictional mechanism is present, experimental results show a significant degradation of bond capacities. Hysteretic cycles show a singular shape, characterized by a reloading phase showing a slight reduction for slip values approaching zero and a subsequent increase in bond stress towards the maximum imposed slip. Bond stresses in cyclic field show a high variability, but it is generally possible to recognize a decreasing trend both with the number of cycles and with the maximum imposed slip.     

Nuclear Data Sheets for A = 102

The 1998 evaluation on mass A = 102 (1998De15) has been revised, taking into account all data available before december 2008. Detailed experimental information is presented from the neutron rich nucleus ¹⁰²Rb to the neutron deficient ¹⁰²Sn nucleus. No information on excited states of ¹⁰²Rb is available and very scarce for ¹⁰²Sr Especially new (HI,xnγ) data sets for several nuclides have been evaluated and new and more accurate data for γ intensities and multipolarities obtained. For ¹⁰²Ru very precise new data of the Budapest (n,γ) collaboration have been included.A new and very elaborated decay scheme for ¹⁰²In is obtained. Isomerism in ¹⁰²Y and ¹⁰²Nb needs further investigation due to conflicting results.     

The universal field oriented controller

This paper synthesizes and develops a universal field oriented (UFO) controller for induction machines. The UFO controller decouples flux and torque in an arbitrary flux reference frame. Due to its high degree of generality the UFO controller lends itself to be fully compatible with all existing field oriented controllers, indirect as well as direct field orientation. As a consequence, the digital implementation of the UFO scheme is identical for all induction motor drives enabling the usage of identical hardware and software. Examples of UFO control block diagrams for different field oriented controllers are presented. The execution time of the UFO algorithm is compared with the classical rotor flux field orientation method when using a high speed digital signal processor. Further, this paper indicates that the flexibility of changing the flux reference frame can extend the stability region of the drive especially at high speed during flux weakening. Detuning problems in field orientation are handled in an optimal manner for each field oriented controller by proper selection of the model of the induction machine and its reference frame