Improving dynamic response of power-factor correctors by usingseries-switching postregulator

A new method to improve the dynamic response of power-factor correctors (PFCs) is described in this paper. The method is based on the use of a new very highly efficient postregulator, called a series-switching postregulator. This new postregulator exhibits very high efficiency due to the fact that only a part of the total power undergoes a power conversion process. The proposed postregulator can be used with any PFC topology (either with or without a transformer), with no modifications in the topology, and can be easily protected against short circuits     

Magnetoelastic behavior of glass-covered amorphous ferromagneticmicrowire

Particular aspects concerning the magnetoelastic behavior of an Fe-rich glass-covered amorphous ferromagnetic microwire (diameter about 20 μm) are reported in both the as-prepared state and after various heat treatments. The main feature of such behavior is that related with the bistable behavior exhibited by the microwire. The magnetization process takes place by a single and large Barkhausen jump at a given applied field. For the as-prepared material, the value of this switching field (H*≈112 Am^-1) is about one order of magnitude larger than that reported for Fe-rich amorphous wires with a diameter of about 125 μm (H*≈8 Am^-1). The effect of the thermal treatment as well as the stress dependence of H* for as-obtained and treated microwire are also reported and discussed in terms of the stress distribution within the microwire     

Electrochemical sensor array made from bisphthalocyanine modified carbon paste electrodes for discrimination of red wines

A new sensor system devoted to the discrimination of red wines is presented. It consists of an array of electrochemical sensors made from carbon paste electrodes modified with three rare-earth bisphthalocyaninate compounds, including lutetium(III), gadolinium(III) and praseodymium(III) bisphthalocyaninates. The sensor responses have been evaluated either by cyclic voltammetry or by square wave voltammetry, and demonstrate that such voltammetric sensors show a rich response when immersed in red wines. In addition, this response can be tuned by changing the central metal atom of the double-decker complexes, obtaining sensing units with high cross-selectivity.

The sensor array is exposed to six Spanish red wines made from the same grape variety, prepared using a similar vinification method, but belonging to three different geographic origins and ageing stages. The voltammograms indicate that each sensing unit provides a particular response to each class of wine.

Finally, the signals coming from each sensor are combined and the system’s discrimination capability is evaluated by using principal component analysis (PCA), where a windowed slicing pre-processing method has been developed to capture the information throughout the global response. The PCA score plots of the obtained data show the discrimination of the tested wines with a good-quality performance.     

Cell Wall Stability of Fresh-Cut Fuji Apples Treated with Calcium Lactate

ABSTRACT:  This article studies the effect of calcium lactate on the structure (using low-temperature scanning electron microscopy, transmission electron microscopy, and light microscopy), texture (penetration test), pectinmethylesterase activity (titration of free carboxylic groups released by the enzyme), and polygalacturonase activity (viscosimetry) on fresh-cut Fuji apples stored for 3 wk at 4 °C. The results show that calcium lactate strengthens the structure of fresh-cut Fuji apple cell walls and counteracts the increased activity of both the pectinmethylesterase and polygalacturonase enzymes. Therefore, it is advisable to treat the product with calcium lactate to improve its structural stability. At a macroscopic level, this calcium treatment maintains the texture for at least 3 wk of storage at 4 °C.     

Reversible Photocontrol of Dopaminergic Transmission in Wild-Type Animals

Understanding the dopaminergic system is a priority in neurobiology and neuropharmacology. Dopamine receptors are involved in the modulation of fundamental physiological functions, and dysregulation of dopaminergic transmission is associated with major neurological disorders. However, the available tools to dissect the endogenous dopaminergic circuits have limited specificity, reversibility, resolution, or require genetic manipulation. Here, we introduce azodopa, a novel photoswitchable ligand that enables reversible spatiotemporal control of dopaminergic transmission. We demonstrate that azodopa activates D₁-like receptors in vitro in a light-dependent manner. Moreover, it enables reversibly photocontrolling zebrafish motility on a timescale of seconds and allows separating the retinal component of dopaminergic neurotransmission. Azodopa increases the overall neural activity in the cortex of anesthetized mice and displays illumination-dependent activity in individual cells. Azodopa is the first photoswitchable dopamine agonist with demonstrated efficacy in wild-type animals and opens the way to remotely controlling dopaminergic neurotransmission for fundamental and therapeutic purposes.     

UHF TV re-emitter antenna system design and optimization with theaid of terrain and environmental data bases

A method for the optimization of TV re-emitter antenna system design is described. In highly interference-limited environments re-emitters' coverages must be confined to the actual shadow areas they are intended to serve, thus limiting interference on other systems nearby. The use of software planning tools using terrain databases is of great value in this optimisation task as is shown in the paper     

Immunochemical determination of gluten in malts and beers.

The gluten content in different varieties of barley and malts, and in different types of beers, was determined by a 'sandwich' enzyme immunoassay (RIDASCREEN Gliadin kit). The gluten levels in barley wheat, rye and spelt malts ranged 18.8-45.0, 44.0-68.0, 41.6 and 21.2 g kg-1, respectively. When various types of beer were compared, the gluten concentration increased as follows: alcohol-free beer (<3.0), lager beers (<3.0-8.7 mg l-1), stouts (9.0-15.2 mg l-1) and wheat beers (10.6-41.2 mg l-1). When 10 Czech lager beers were analysed, using both sandwich and competitive ELISA, the results showed that the latter method provided values several times higher than the former. Gluten balance was carried out during the brewing process, starting from the raw materials and terminating at the final beer. Gluten levels decreased due to precipitation during the mashing process, primary and secondary fermentation and, lastly, as a result of adsorption during beer stabilization. The gluten content in beer is, thus, approximately three orders of magnitude lower than in the raw malt.     

Terrestrial radio links engineering for frequencies above 10 GHz with reference to rain attenuation

This paper describes the theoretical background and the process of obtaining maximum hop lengths and minimum fading margins (if the terminal or repeater locations are fixed) in any region of the world and gives a set of curves providing these characteristics for 1 km with availability of 99.7 % of the time (per 2 500 km), for a given frequency and polarization. Correction factors for other availabilities are also given.