Advances in liquid based photovoltaic/thermal (PV/T) collectors

In order to get more power and heat from PV/T system, it is necessary to cool the PV cell and decrease its temperature. This is not an easy task especially in hot and humid climate areas. There is a lack of an effective cooling strategy of PV/T panels. The liquid based photovoltaic thermal collector systems are practically more desirable and effective than air based systems. Temperature fluctuation in liquid based PV/T is much less than the air based PV/T collectors which subjected to variation in solar radiation levels. In this study a review of the available literature on PV/T collector systems which utilize water and refrigerant (working fluid) as heat removal medium for different applications has been conducted. Future direction of water-cooled and refrigerant hybrid photovoltaic thermal systems was presented. This study revealed that the direct expansion solar-assisted heat pump system achieved better cooling effect of the PV/T collector.     

Sedimentation of the Nurek reservoir

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 59–62, October, 1991.     

Double-resonance quartz crystal oscillator and excitation of a resonator immersed in liquid media

In this work we propose a novel circuit design: a double-resonance oscillator. Its oscillation shows two oscillation modes: frequency locking to the quartz crystal resonance and LC resonance oscillation. Transition of the oscillation mode and the strength of oscillation are analyzed and reviewed for the fundamental mode in comparison with a Colpitts oscillator. The experimental results support the estimates of negative resistance for the double-resonance oscillator compared with the LC oscillator.     

Ultrafine-grained Ti–Nb–Ta–Zr alloy produced by ECAP at room temperature

To ascertain the influence of severe plastic deformation (SPD) on a Ti–Nb–Ta–Zr (TNTZ) alloy, we studied the room temperature mechanical behavior and microstructural evolution of an ultrafine-grained (UFG) Ti–36Nb–2Ta–3Zr (wt%) alloy prepared via equal-channel angular pressing (ECAP) of the as-hot-extruded alloy. The tensile behavior, phase composition, grain size, preferred orientation, and dislocation density of the UFG alloy, processed under different conditions, were analyzed and discussed. Compared to the as-hot-extruded alloy, the ECAP-processed TNTZ alloy (3 passes) exhibited approximately 40 and 88 % increase in average ultimate strength and yield strength, respectively. Moreover, as the number of ECAP passes increased from 3 to 6, the TNTZ alloy exhibited not only the expected increase in ultimate and yield strength values, but also a slight increase in elongation. Our results suggest that the deformation mechanisms that govern the behavior of the as-hot-extruded coarse grained (CG) TNTZ alloy during ECAP involve a combination of stress-induced martensitic transformation and dislocation activity. In the case of the ECAP-processed UFG TNTZ alloy, the deformation mechanism is proposed to involve two components: first, dislocation activity induced by the strain field imposed during ECAP; and second, the formation of α″ martensite phase during the early stages of ECAP which eventually transforms into β phase during continued deformation. We propose that the deformation mechanism governing the room temperature behavior of the TNTZ alloy strongly depends on the grain size of the β phase.     

Experimental Study of Antispasmodic Activity of 2-Oksoindolin-3-Glyoxylic Acid Derivatives

Clinical psychiatry and neurology requires a creation of new means with difficult many component range of psychotropic action, so psychoemotional disturbances ＂boundary type＂ and difficult mental disorders have high level of heterogeneity, various clinical manifestations, which are caused by different pathogenetic factors. One of the most often used preparation for the treatment of these diseases is anxiolytic medications. It is known that anxiolytic action combines with anticonvulsive. Perspective medications are simple amides and ethers of 2-oksoindolin-3-glyoxylic acid, which have not recognized and practically observed. The aim of this research is to determine anticonvulsant action in 2-oksoindolin-3-glyoxylic acid derivatives on the model of acute myoclonic pentylentetrazol, piktrotoxic, and bikukullin convulsions. In experiments on mature mice of both sex Wistar line were studied an influence of ethyl ester 4-[2-hydroxy-2-（2-oxo-1,2-dihydro-indol-3-ylidene）-acetylamino]-butyric acid and 2-hydroxy-N-naphthalen-l-yl-2-（2-oxo-l,2-dihydro-indol-3-ylidene）-acetamide on chemoinduced epileptogenesis. An intake of proconvulsants is accompanied by a development of syndrome convulsion, which was estimated by convulsion＇s intensity （grades）, latent period of convulsions （sec.）, number of convulsions acts, and duration of convulsions （sec.） and number of survived animals in a group. It was showed that a combination of 2-hydroxy-N-naphthalen-1-yl-2-（2-oxo-1,2-dihydro-indol-3-ylidene）-acetamide （12 acetamide mg/kg） is similar to reference preparation diazepam in （2 mg/kg） which decreased a manifestation of syndrome convulsion. It demonstrated an increase of intensity of convulsions, decrease of latent period of the convulsion＇s start which is caused by all blockers GAMKA-receptors, decrease of number convulsive acts on the background of korazol and pikrotoxin, a decrease of convulsive syndrome duration during an intake ofkorazol and bikukullin, and a decrease of animal＇s mortalit     

Combined In Silico,Ex Vivo,and In Vivo Assessment of L-17, a Thiadiazine Derivative with Putative Neuro- and Cardioprotective and Antidepressant Effects

Depression associated with poor general medical condition, such as post-stroke (PSD) or post-myocardial infarction (PMID) depression, is characterized by resistance to classical antidepressants. Special treatment strategies should thus be developed for these conditions. Our study aims to investigate the mechanism of action of 2-morpholino-5-phenyl-6H-1,3,4-thiadiazine, hydrobromide (L-17), a recently designed thiadiazine derivative with putative neuro- and cardioprotective and antidepressant-like effects, using combined in silico (for prediction of the molecular binding mechanisms), ex vivo (for assessment of the neural excitability using c-Fos immunocytochemistry), and in vivo (for direct examination of the neuronal excitability) methodological approaches. We found that the predicted binding affinities of L-17 to serotonin (5-HT) transporter (SERT) and 5-HT₃ and 5-HT_1A receptors are compatible with selective 5-HT serotonin reuptake inhibitors (SSRIs) and antagonists of 5-HT₃ and 5-HT_1A receptors, respectively. L-17 robustly increased c-Fos immunoreactivity in the amygdala and decreased it in the hippocampus. L-17 dose-dependently inhibited 5-HT neurons of the dorsal raphe nucleus; this inhibition was partially reversed by the 5-HT_1A antagonist WAY100135. We suggest that L-17 is a potent 5-HT reuptake inhibitor and partial antagonist of 5-HT₃ and 5-HT_1A receptors; the effects of L-17 on amygdaloid and hippocampal excitability might be mediated via 5-HT, and putatively mediate the antidepressant-like effects of this drug. Since L-17 also possesses neuro- and cardioprotective properties, it can be beneficial in PSD and PMID. Combined in silico predictions with ex vivo neurochemical and in vivo electrophysiological assessments might be a useful strategy for early assessment of the efficacy and neural mechanism of action of novel CNS drugs.