The JDTDOA algorithm applied to signal recovery: a performance analysis

This article suggests a novel method to retrieve a narrowband signal sent in a multipath environment with a delay spread considering ISI between symbols. The proposed method does not require any preamble nor known signal. Using the joint direction and time delay of arrivals estimation algorithm developed in prior work, the directions and time delays of arrival in the multipath channel are jointly estimated and associated while keeping a low computational cost. In this process, a MVDR beamformed copy of each arriving signal is created. The quality of these “pseudo copies” is evaluated and compared to the original direct and reflected signals in this work. Another beamforming method, the Moore–Penrose pseudoinverse, with better retrieval of the direct and reflected signals is also proposed. Using a simple delay-and-sum operation on the previously beamformed copies, it is possible to substantially improve the the system’s performance in terms of bit error rate. An approach using oversampling on the array antenna is introduced to improve performance. Numerical simulations are discussed to support theory.     

HOT AIR AND MICROWAVE DRYING OF ONIONS: A COMPARATIVE STUDY

ABSTRACT

This comparative study of conventional (hot air) drying and microwave drying of the onion was carried out on a hot air pilot plant drier for conventional drying where all characteristics (temperature, humidity, and velocity) could be adjusted and controlled. A data logger connected to a computer captured all data. And for microwave drying, a drying tunnel Fitted with a forward/backward movement was used. Mass loss and product surface temperature were monitored for both processing. Factors controlled where: frequency of movement, microwave power, air extraction rate. Other elements included shape (slices/pieces) and variety of product

Drying duration and maximum drying rate constituted comparative criterion for the processes. Quality was measured by the reducing sugars and polyfructans content. Analysis of variance for the microwave drying process suggests that the effective factors were microwave power followed by onion variety and shape respectively. For quality criterion by far the most effective was variety, followed by the interaction of shape and the forward-backward movement of the conveyor. For conventional drying the most effective factor was air temperature for drying duration, and variety for maximum drying rate.     

Bubble growth and collapse in pre-fermented doughs during freezing,thawing and final proving

The formation of large bubbles was observed by MRI during freezing. This was attributed to the compression of gases in a structure that cannot globally deform (due to the frozen “shell”), the consecutive rupture of dough films and the coalescence of neighbouring bubbles. The fraction occupied by these large bubbles was consistent with the hypothesis of thermal contraction, though this was not the only mechanism in play. Conversely medium-sized bubbles initially present in the dough did not grow during freezing, suggesting that maximum stress was dependent on location.These large bubbles were suspected to contribute greatly to dough collapse just after thawing since they were still present in the thawed dough, but in an elongated form. Collapse was related to delayed expansion during the second fermentation stage. The longer the duration of the first fermentation stage, the more collapsed the dough structure became just after thawing and the coarser the dough structure was at the end of the second fermentation period.     

Development and operation of alternative oxygen electrode materials for hydrogen production by high temperature steam electrolysis

High temperature steam electrolysis (HTSE) is one of the most promising ways for hydrogen mass production. To make this technology suitable from an economical point of view, each component of the system has to be optimized, from the balance of plant to the single solid oxide electrolysis cell. At this level, the optimization of the oxygen electrode is of particular interest since it contributes to a large extent to the cell polarization resistance. The present paper is focused on alternative oxygen electrode materials with improved performances compared to the usual ones mainly based on perovskite structure. Two nickelates, with compositions La₂NiO_4+δ and Nd₂NiO_4+δ are investigated and evaluated in HTSE operation at the button cell level. The performances of the Ln₂NiO_4+δ - containing cells (Ln = La, Nd) is improved compared to a cell containing the classical Sr-doped LaMnO₃ (LSM) perovskite oxygen electrode showing that nickelates are promising candidates for HTSE oxygen electrodes, especially for operation below 800 °C. Indeed, current densities determined at 1.3 V are 1.1 times larger for the La₂NiO_4+δ - containing cell and 1.6 times larger for the Nd₂NiO_4+δ one compared to the LSM - containing cell at 850 °C, whereas at 750 °C they are 1.8 and 4.4 times larger, respectively. Thanks to the use of a reference electrode, by coupling impedance spectroscopy and polarization measurements, the overpotential of each working electrode is deconvoluted from the complete cell voltage under HTSE operating conditions.     

Etude d'une machine solaire autonome à fabriquer de la glaceStudy of a package solar ice maker

Une machine solaire à fabriquer de la glace, d'une surface de captation de 0,8 m², a été étudiée en vue de la réalisation d'une machine industrielle. C'est une machine à adsorption à cycle intermittent journalier qui utilise le couple charbon actif AC 35-méthanol. Elle est trés simple puisque le même échangeur sert tantôt d'évaporateur, tantôt de condenseur. La gestion du systéme consiste uniquement à déplacer cet échangeur entre le bac à glace isolé thermiquement et une réserve d'eau à température ambiante, et à manoeuver les volets d'aération pour le chauffage et le refroidissement du capteur. Aucune vanne n'est nécessaire. Les résultats montrent qu'avec un rendement de captation de 0,41 et un COP thermique de 0,40, il est possible d'obtenir un COP solaire brut (rapporté à la quantité de méthanol cyclée) élevé: 0,15. Une isolation insuffisante du bac à glace a conduit à un COP net environ 2 fois plus faible. Cette machine a produit journellement 4 kg de glace en été, ce qui correspond à une production quotidienne (non optimisée) de 5 kg de glace par m² de surface de captation.

Abstract

A solar ice maker with a 0.8 m² collection surface was studied with a view to building an industrial machine. It is an adsorption machine with an intermittent daily cycle that uses the active carbon Ac 35-methanol pair. It is very simple in that the same exchanger can be used either as an evaporator or as a condenser. The system management consists simply of moving this exchanger between the thermally insulated ice bank and an ambient-temperature water tank, and in actuating the ventilation ports for the heating and cooling of the collector. No valve is required. The results show that, with a collection efficiency of 0.41 and a thermal COP of 0.40, it is possible to obtain a gross solar COP of 0.15 (as a function of the quantity of methanol). Because of insufficient insulation of the ice bank, the net COP obtained was twice as low. This machine produced 4 kg of ice per day, during summer, which corresponds to a daily output (non-optimized) of 5 kg ice per square metre of collection surface.     

Le trouble obsessionnel-compulsif et l'insight: Une revue critique de la littérature.

It is assumed that an individual suffers from obsessive-compulsive disorder (OCD) with poor insight when he or she does not recognize for most of the time that his or her obsessions/compulsions are unreasonable (American Psychiatric Association, 2000). In this critical review of research concerning insight in obsessions, overvalued ideas and delusions, we propose several factors that should be considered when evaluating insight. The instruments frequently used to evaluate insight in OCD patients are critically discussed. Often they assess insight principally in medical terms (e.g., the capacity to recognize that one's behaviour is the result of a mental disorder) without considering the cognitive dimensions. Other instruments designed specifically for OCD assess insight on the basis of the anticipated consequences of not executing one ritual but these instruments do not distinguish this from obsessional doubts. Measures of insight for OCD may need to consider that OCD has several independent components and conviction may vary according to level initial doubt as well to type of consequence. A multidimensional model that evaluates three cognitive dimensions of insight in OCD patients is presented (the Inference Based Approach). This cognitive model establishes a clear distinction between the obsessional doubts, the anticipated consequences and the degree of conviction in the need to perform the ritual. Further recommendations are presented to evaluate insight in OCD patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of VIP on intestinal motility: study on ex vivo perfused isolated canine jejunal loops

The effects of VIP on intestinal motility were studied on isolated canine jejunal loops ex vivo perfused at normothermia, under pulsatile flow with heparinized, oxygenated and nonrecirculated canine whole blood, by means of an intraluminal balloon. VIP was administered intraarterially either by 1 min injections or by long-time infusions. The results showed that for arterial concentrations of the polypeptide ranging between 25 pg/ml and 300-500 pg/ml a fast but short-lasting relaxant effect was observed. For higher concentrations VIP usually produced a biphasic response: The relaxant effect is followed by an increase of the basal muscular tone often accompanied, for concentrations higher than about 25 ng/ml, by a marked and transient increase in amplitude of the intestinal rhythmic contractions. During long-time infusions a biphasic response was also observed but both effects were of short duration. A cholingeric origin of the secondary contracting phase was expected but could not be demonstrated because, at blood concentrations at which atropine affected the biphasic response, not only was the contractile effect abolished but also the initial relaxing phase. It is suggested that the secondary contraction may be a "rebound excitation" of myogenic nature or a result of noncholingeric excitatory fiber stimulations. The short-lasting relaxant effect observed under the present experimental conditions, even during long-time infusion of the polypeptide, fails to argue for an important physiological role of VIP as an hormonal inhibitor of intestinal motility. The biphasic response, however, might have a physiological significance in so far as the aboral propulsion of the intestinal content requires a muscular inhibition which rapidly changes to contraction.     

Modeling bread baking with focus on overall deformation and local porosity evolution

A two dimensional model of bread baking was developed including, for the first time, the dependence of dough viscosity on both temperature and moisture content, the carbon dioxide dissolved from liquid water together with gas generation from yeast at the beginning of baking and the shrinkage due to dough drying. Particular attention was paid to experimental validation of both overall and local variables such as local temperature, overall mass loss, and local moisture content, overall CO₂ released into the oven, and overall deformation and local expansion or shrinkage. Sensitivity studies on generation of carbon dioxide, gravity, and shrinkage are presented to discuss their influences on bread geometry, porosity (reflecting the alveolar structure) and gas pressure. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3847–3863, 2016