Closed form solutions for plane-strain ideal plastic deformations

A Riemann plane mapping methodology to analyze plane-strain ideal plastic flow processes such as extrusion and drawing is presented. A solution function for a generalized die profile is obtained in the form of a zeroth-order Bessel function. Explicit solutions in closed form using functional approximation are obtained for the deformation forces and stresses for a wedge-shaped die without requiring numerical evaluation of any integrals. Two limiting solutions of the wedge shaped die profile, including wall friction effects, are derived and discussed. A comparison of the method and the results with the traditional slip-line field and upper-bound-lower-bound approaches is provided.     

The regional distribution of Spanish unemployment: A spatial analysis

In this article we propose a set of tools for analysing the regional distribution of unemployment. As we are interested in the characteristics of the distribution as a whole, results from a traditional regression analysis are complemented with those obtained by estimating its external shape before and after being conditioned to factors underlying regional unemployment. In addition, we specifically consider the spatial characteristics of the distribution, and the empirical model we develop to determine explanatory factors includes spatial effects. This framework is applied to the study of the provincial distribution of unemployment rates in Spain. Results point to increasing spatial dependence in the distribution of regional unemployment rates, and a change in the factors causing regional differentials over the last decade.     

The radar in the automotive domain

The principle of radar is based on the propagation of electromagnetic radiation. Reflection of this radiation may be used to detect a target’s presence and, subsequently, to calculate its position and speed. The first practical radar applications date from before second World War but radar techniques are widely used nowadays in a large number of mostly military or “professional” civilian applications. They make use of extremely high frequencies generated by traditionally expensive technologies. Recent advances in electronics components, in terms of speed of development and cost, allow us to predict radar being used for civilian mass-market products, such as motor cars. In particular, these advances concern RF components in the millimeter wave bands with high-speed, wide-range digitization systems and digital signal processors. Included amongst the potential motor industry applications are:

– Intelligent road-speed control (Adaptive Cruise Control),

– Its urban driving equivalent, Stop and Go,

– Short-range applications (parking aids, etc),

– Anti-collision systems (against fixed or moving objects).

     

The digital agenda of virtual currencies: Can BitCoin become a global currency?

This paper identifies and analyzes BitCoin features which may facilitate BitCoin to become a global currency, as well as characteristics which may impede the use of BitCoin as a medium of exchange, a unit of account and a store of value, and compares BitCoin with standard currencies with respect to the main functions of money. Among all analyzed BitCoin features, the extreme price volatility stands out most clearly compared to standard currencies. In order to understand the reasons for such extreme price volatility, we attempt to identify drivers of BitCoin price formation and estimate their importance econometrically. We apply time-series analytical mechanisms to daily data for the 2009–2014 period. Our estimation results suggest that BitCoin attractiveness indicators are the strongest drivers of BitCoin price followed by market forces. In contrast, macro-financial developments do not determine BitCoin price in the long-run. Our findings suggest that as long as BitCoin price will be mainly driven by speculative investments, BitCoin will not be able to compete with standard currencies.     

Potent alpha 4 beta 1 peptide antagonists as potential anti-inflammatory agents

The migration, adhesion, and subsequent extravasation of leukocytes into inflamed tissues contribute to the pathogenesis of a variety of inflammatory diseases including asthma, rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis. The integrin adhesion receptor alpha 4 beta 1 expressed on leukocytes binds to the extracellular matrix protein fibronectin and to the cytokine inducible vascular cell adhesion molecule-1 (VCAM-1) at inflamed sites. Binding of alpha 4 beta 1 to VCAM-1 initiates firm adhesion of the leukocyte to the vascular endothelium followed by extravasation into the tissue. Monoclonal antibodies generated against either alpha 4 beta 1 or VCAM-1 can moderate this inflammatory response in a variety of animal models. Recently peptides containing a consensus LDV sequence based on the connecting segment-1 (CS-1) of fibronectin and cyclic peptides containing an RCD motif have shown promise in modulating leukocyte migration and inflammation presumably by blocking the interaction of alpha 4 beta 1 with VCAM-1. Here we describe novel, highly potent, cyclic peptides that competitively inhibit alpha 4 beta 1 binding to VCAM-1 and fibronectin at sub nanomolar concentrations. The structure of a representative analog was determined via NMR spectroscopy and used to facilitate optimization of peptide leads. The peptides discussed here utilize similar functional groups as the binding epitope of VCAM-1, inhibit lymphocyte migration in vivo, and are highly selective for alpha 4 beta 1. Furthermore the structure--activity relationships described here have provided a template for the structure-based design of small molecule antagonists of alpha 4 beta 1-mediated cell adhesion processes.     

Polyisoprene-nanostructured carbon composite – A soft alternative for pressure sensor application

Latest related research shows natural polyisoprene-nanostructured carbon composite (PNCC) as a promising piezoresistive material for soft pressure sensors. The main advantages of PNCC over conventional sensors are exceptional sensitivity in pressure range from 0.1 to 10 bar and possibility to be embedded into completely soft (hyper-elastic) structures.In this work we have elaborated a completely soft (hyper-elastic) PNCC pressure sensor prototype, made using functional multi-layer approach, when elementary layers of PNCC with different conductive filler concentration are cured together and form a uniform sensor body with integrated soft (hyper-elastic) electrodes. We proposed also a theoretical model to explain the observed positive piezoresistivity and used it for fitting of our experimental results.The prototype system elaborated could be used for counting interface events between sensor and external environmental factor. The achieved result could be a step towards the artificial skin, capable to sense non-destructive interaction with the external influence.     

Selective and Brain‐Permeable Polo‐like Kinase‐2 (Plk‐2) Inhibitors That Reduce α‐Synuclein Phosphorylation in Rat Brain

Polo‐like kinase‐2 (Plk‐2) has been implicated as the dominant kinase involved in the phosphorylation of α‐synuclein in Lewy bodies, which are one of the hallmarks of Parkinson’s disease neuropathology. Potent, selective, brain‐penetrant inhibitors of Plk‐2 were obtained from a structure‐guided drug discovery approach driven by the first reported Plk‐2–inhibitor complexes. The best of these compounds showed excellent isoform and kinome‐wide selectivity, with physicochemical properties sufficient to interrogate the role of Plk‐2 inhibition in vivo. One such compound significantly decreased phosphorylation of α‐synuclein in rat brain upon oral administration and represents a useful probe for future studies of this therapeutic avenue toward the potential treatment of Parkinson’s disease.     

Survey of emissivity variability in thermography of urban areas

This study investigates the effects of roof emissivity variation of aerial thermogram images. Thermograms have been used to detect heat loss from residential roofs. Emissivity variation among rooftops, however, can lead to a misrepresentation of the temperatures mapped in a thermogram image. The objectives of this study were (a) to demonstrate the feasibility of a technique to use remotely sensed data to calculate surface emissivities and (b) to apply that technique, to determine the extent of emissivity variation in urban surfaces. In the first part of the experimental approach a passive technique is developed to calculate emissivity from two-band thermal infrared radiance data. Inherent limitations and sources of error associated with the technique are discussed. In the second part of the experimental approach the technique was used to measure the emissivity of 1411 roofs within the city limits of Terre Haute, Indiana. Results of this survey indicated that over 98% of the roofs surveyed were confined to a very narrow range of emissivities. It is concluded that the observed variation in rooftop emissivities has a minimal effect on the temperatures depicted in thermograms.     

Polyisoprene-multi wall carbon nanotube composite structure for flexible pressure sensor application

The major problem of conventional rigid sensor materials is difficulty to integer them into soft flexible structures. Piezoresistive polyisoprene/nanostructured carbon composite appears as promising materials for such application. Previous research approved high structure carbon black and carbon nanotube filled composites as finger pressure sensitive piezoresistive materials. Carbon nanotubes originate with variable length to width ratio and high electric conductivity in longitudinal direction of the tubes, which theoretically should make it possible to obtain electric percolation in polymercarbon nanotube composites at very low loads of filler. However recent experience with mechanically dispersed carbon nanotubes shows quite high values of percolation threshold and specific sensing properties. In this work we present an attempt to use ultrasound for improved dispersion of the filler in a piezoresistive polyisoprene-multi wall carbon nanotube composite as well polyisoprene-high structure carbon black composite. The noticeable shift of percolation threshold for both types of composites have been achieved. The piezoresistive behavior of sonicated composites have been determined and compared with mechanically mixed ones. The differences have been evaluated and explained.