A simplified mathematical model for predicting the nocturnal output of a solar still

The production capacity of a solar still which converts saline water to fresh water can be increased by introducing hot feed water into the unit at night. A waste heat source, such as cooling water from a power plant, can be used to preheat the feed. The nocturnal production, i.e. the distilled water produced at night, seems to be influenced by several parameters. However, a simplified mathematical model suggests that the distillate depends only on the initial brine temperature, the drop in brine temperature and the brine depth. This was experimentally verified for different brine depths and for initial brine temperatures up to 150°F.     

Skin surface lipids of the horse

Skin surface lipids from the sides of male and female horses (Equus caballus) were collected in acetone and analyzed by thin layer chromatography and gas liquid chromatography. The sole components in both sexes were cholesterol, cholesteryl esters and the lactones of 32-, 32- and 36-carbon ω-hydroxy acids, each including a methyl group in the n−1 position. Most of the lactones were mono-unsaturated (either n−8 or n−10), but small amounts of saturated and dienoic species were present. A pooled sample of the skin surface lipids contained 14% cholesterol, 38% cholesteryl esters and 48% lactones.     

Effect of sitosterol on autoxidation rate and product composition in a model lipid system

The effect of 5% sitosterol on the autoxidation of tristearin at 120°C was investigated. It was found that sitosterol caused a two-fold increase in the process rate; this effect was unchanged at peroxide concentrations of up to 350 mEq kg^?-1. It was established that introduction of 5% sitosterol considerably increased the concentration of oxidised products in tristearin (from 0.5 to 6.5%) after oxidation at 120°C for 7h. The degree of oxidation of sitosterol in the system was found to be 56%. The structure and composition of oxidised products in the two lipid systems (tristearin, and tristearin+5% sitosterol) were determined. Conclusions were drawn concerning the effect of the lipid medium on the composition and structure of the products of sitosterol autoxidation.     

Possibilities of using welding-on technologies in crane wheel renovation

The paper deals with analysis of welds-on quality of traverse crane wheels made from gr. 90-60 material, ASTM A148. Three types of welding-on technology with various filling materials were used. On wheel after wearing was welded-on one interlayer by a combination of additional materials, wire A 106 with F 11 addition and two cover layers made by a combination of A 508 wire with F 13 addition. Wheel surface was hardened after welding-on to a depth of 3 mm. A second welds-on technology was a combination of A 106 wire with F 11 addition. Two cover layers were made by a combination of RD 520 wire with F 56 addition. Third welds-on technology was realized to face one layer by C 113 wire in inert atmosphere: 80% Ar + 20% CO₂. Two cover layers were made by wire with self protect Lincore 40-O. Properties of renovated traverse crane wheels were compared with the properties of new wheels with surface hardened layer. The welds-on were exposed to adhesive wearing where surface resistance was examined according to their weight loss. Influence of a particular element on the welds-on chemical composition was examined by EDX analyses.     

Plasma treatment of wood–polymer composites: A comparison of three different discharge types and their effect on surface properties

Three different discharge types, based on the principle of a dielectric barrier discharge at atmospheric pressure, were investigated with regard to their influence on the adhesion properties of a series of wood–polymer composites. Wood flour (Picea abies L.) filled polypropylene and various proportions of polyethylene were manufactured either through extrusion or injection molding. The composites’ surfaces were activated by coplanar surface barrier discharge, remote plasma, and direct dielectric barrier discharge. The changes in wettability due to the pretreatment were investigated by contact angle measurement using the sessile drop method and calculation of surface free energy (SFE). It could be shown that wettability was improved by all three types of discharge, the contact angle decreased and the SFE correspondingly increased. X‐ray photoelectron spectroscopy revealed an increase in the O/C ratio at the material's surface. An improvement in coating adhesion was demonstrated by crosscut and pulloff tests. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43376.     

8-Substituted 3-arylcoumarins as potent and selective MAO-B inhibitors: synthesis, pharmacological evaluation, and docking studies

Neurodegenerative disorders are becoming more prevalent given the increase in the aging population. This has inspired active research in the development of new drugs that could mark an important advance in the treatment of complex diseases such as Alzheimer's and Parkinson's. With the aim of finding new MAO-B-selective inhibitors, we report the synthesis, in?vitro evaluation, and docking simulation of a new series of 3-arylcoumarins variously substituted at the 8-position. Most of the studied compounds show high affinity and selectivity for the hMAO-B isoform, with IC?? values in the low micro- to nanomolar range. Some of them have greater hMAO-B inhibitory activity and selectivity than the reference compound, selegiline. Compounds 7 and 8 are the most active of this series, with compound 8 being fivefold more potent against MAO-B and severalfold more selective than selegiline. Docking experiments were carried out with hMAO-B crystal structures, providing new information about the enzyme-inhibitor interaction and the potential therapeutic application of the new 8-substituted 3-arylcoumarins.     

Bioactivity of Lemon Balm Kombucha

There is inadequate published data referring to bioactivity of lemon balm tea and its Kombucha. The aim of this study, therefore, was to investigate antimicrobial, antiproliferative, genotoxic, and antigenotoxic potential of lemon balm tea and its Kombucha with consuming acidity. Antimicrobial activity was determined by agar-well diffusion method. Cell growth effects were determined in HeLa, MCF7, and HT-29 human tumor cell lines. Genotoxic and antigenotoxic effects were determined using chromosome aberration assay in Chinese hamster cell line CHO-K1. Differences between control and treated groups were evaluated using analysis of variance, at significance level of p < 0.05. Kombucha from lemon balm tea (Melissa officinalis L.) exibited antimicrobial activity against prokaryotic microorganisms independently of their cell wall structure (both Gram-positive and Gram-negative bacteria), while there was no observed activity against eukaryots (yeasts and moulds). There was absence of genotoxic effects while antigenotoxic effects of lemon balm Kombucha and tea were confirmed on MMC-damaged CHO-K1 cells. For the explanation of cell growth effects that were not concentration dependent, concept of hormesis was used. Antiproliferative activity was lower compared with traditional Kombucha and Satureja montana L. Kombucha, with lemon balm tea showing higher activity than its Kombucha.     

On the interaction of polycyclic aromatic compounds with graphene

The adsorption and diffusion of benzene, hexafluorinated benzene, perylene, perylene-3,4,9,10-tetracarboxylic-3,4,9,10-diimide (PTCDI) and perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) on graphene has been studied by density functional means on a generalized gradient approximation level, including a semi-empirical correction to account for dispersive forces. It is shown that for all considered molecules the adsorption strength is mainly due to the latter, with the electronic interaction being relatively small and repulsive. As a rule-of-thumb, the strength of the adsorption interaction is 11–13 kJ mol^?1 per C atom. The adsorption energies are large enough to avoid desorption at room temperature. The estimated diffusion and rotation barriers are remarkably small, thus allowing a rapid diffusion and self-arrangement even at cryogenic temperatures. Finally, the adsorption of benzene or perylene derivatives may act, depending on the molecule and nature of the substituents, as a source for n- or p-doping, achieving up to 0.2 electrons(holes)/molecule. The lowest unoccupied molecular orbitals of PTCDI and PTCDA are close in energy to the Dirac point of graphene and induce a conduction gap of ～210–240 meV in the graphene band structure. Thus, they can be used for graphene band gap engineering and doping by the non-aggressive method of molecular adsorption.     

Development of a thermoelectric refrigerator with two-phase thermosyphons and capillary lift

A thermoelectric domestic refrigerator has been developed, with a single compartment of 0.225 m³, for food preservation at 5 °C. The cooling system is made up of two equal thermoelectric devices, each composed of a Peltier module (50 W) with its hot side in contact with a two-phase and natural convection thermosyphon (TSV) and a two-phase and capillary lift thermosyphon (TPM), in contact with the cold side.The entire refrigerator has been simulated and designed using a computational model, based on the finite difference method. Subsequently an experimental optimization phase of the thermosyphons was carried out, until thermal resistance values of R_TSV = 0.256 K/W and R_TPM = 0.323 K/W were obtained. These values were lower than those obtained with finned heat sinks.Finally, a functional prototype of a thermoelectric refrigerator was built, and the results which were obtained demonstrate that it is able to maintain a thermal drop (Ambient Temperature–Inside Temperature) of 19 °C. The electric power consumption at nominal conditions was 45 W, reaching a COP value of 0.45. The study demonstrated that by incorporating these two-phase devices into thermoelectric refrigeration increases the COP by 66%, compared with those which use finned heat sinks.     

Microwave drying of wet processed wood fibre insulating boards

A continuous microwave dryer was used for drying wet processed wood fibre based insulating boards. Drying characteristics and energy consumption were compared with convective drying methods. Microwave drying turned out to be faster and facilitates even economical drying of thick boards.