Preliminary results of a V-groove back-pass solar collector

The study conducted by the Solar Energy Research Group, Universiti Kebangsaan Malaysia shows that solar energy has a great potential to be used in drying processes. A prototype solar drying system was designed and tested in the campus (Othman et. al, 1994). The study shows that the system can be upgraded by improving the solar collector. This paper presents the preliminary result on the performance of the V-groove back-pass solar collector modified from V-groove double flow solar collector designed earlier (Othman et. al, 1992). The results shows that the collector maintained the output temperature eventhough there are changes of solar radiation intensity. At 0.65 ms⁻¹ air flow rate, the output temperature of the collector can manage to maintain 40°C in the range of solar intensity of 800 Wm⁻² to 300 Wm⁻² within 15 minutes time interval, and at 0.45 ms⁻¹, the output temperature is 43°C in the range of solar intensity of 800 Wm⁻² to 600 Wm⁻². The min daily efficiency of 20% is recorded at 450 Wm⁻² of min daily solar radiation at 0.65 ms⁻¹ flow rate. At 0.45 ms⁻¹ flow rate with the equal amount of daily min solar radiation the min daily efficiency is 13%. The result is expected to be better if the study is conducted in May - June when the weather is better.     

Asynchronous sum‐of‐products logic minimization and orthogonalization

We propose a method of the asynchronous sum‐of‐products (SOP) logic simplification that comprises of minimization and orthogonalization. The method is based on a transformation of the conventional single‐rail SOP synchronous logic into the dual‐rail asynchronous one operating under so‐called modified weak constraints. We formulate and prove the product terms constraint that ensures a correct logic behavior. We have processed the MCNC benchmarks and generated the asynchronous SOP logic. The complexity of the logic obtained is compared with the state‐of‐the‐art representation. Using our approach, we achieve a significant improvement. Copyright © 2012 John Wiley & Sons, Ltd.     

Grain Boundaries and Mechanical Properties of Ultrafine-Grained Metals

The concept of grain boundary (GB) engineering of ultrafine-grained (UFG) metals and alloys is developed for enhancement of their properties by tailoring different GBs (low-angle and high-angle ones, special and random, or equilibrium and nonequilibrium) and formation of GB segregations and precipitations by severe plastic deformation (SPD) processing. In this article, using this approach and varying regimes and routes of SPD processing, we show for several light alloys (Al and Ti) the ability to produce UFG materials with different GBs, and this can have a dramatic effect on the mechanical behavior of the processed materials. This article demonstrates also several new examples of attaining superior strength and ductility as well as enhanced superplasticity at low temperatures and high strain rates in various UFG metals and alloys.     

Toward efficient binders for Li-ion battery Si-based anodes: polyacrylic acid

Si-based Li-ion battery anodes offer specific capacity an order of magnitude beyond that of conventional graphite. However, the formation of stable Si anodes is a challenge because of significant volume changes occurring during their electrochemical alloying and dealloying with Li. Binder selection and optimization may allow significant improvements in the stability of Si-based anodes. Most studies of Si anodes have involved the use of carboxymethylcellulose (CMC) and poly(vinylidene fluoride) (PVDF) binders. Herein, we show for the first time that pure poly(acrylic acid) (PAA), possessing certain mechanical properties comparable to those of CMC but containing a higher concentration of carboxylic functional groups, may offer superior performance as a binder for Si anodes. We further show the positive impact of carbon coating on the stability of the anode. The carbon-coated Si nanopowder anodes, tested between 0.01 and 1 V vs Li/Li+ and containing as little as 15 wt % of PAA, showed excellent stability during the first hundred cycles. The results obtained open new avenues to explore a novel series of binders from the polyvinyl acids (PVA) family.     

Evolution of grain boundary structure in submicrometer-grained Al-Mg alloy

This paper presents high-resolution electron microscopy studies of grain boundary structures in a submicrometer-grained Al-3%Mg solid solution alloy produced by an intense plastic straining technique. The studies include the effect of static annealing on the grain boundary structure. Many grain boundaries are in a high-energy nonequilibrium state in the as-strained sample. The nonequilibrium character is retained on some grain boundaries in samples annealed at temperatures below the onset of significant grain growth. The effect of electron irradiation on the grain boundary structure also is examined.     

Investigation of Nitramine‐Based Amorphous Energetics

To date, the use of high explosives (HEs) has been largely limited to their crystalline forms. The glassy forms of these materials have not received much attention. While the highest density and stability of HEs is only attainable in the crystalline state, the unique properties exhibited by glasses may offer significant practical advantages. In this work, the production and properties of glassy molecular dispersions based on CL‐20 with HMX and polyvinyl acetate additives were investigated. The glassy form was achieved by rapid precipitation of the composite ingredients using spray drying. The role of the additives on glass formation was examined. Characterization revealed multiple novel properties in comparison to the traditional crystalline HE‐based compositions. Differential scanning calorimetry (DSC) analysis showed that in the glassy state the materials have a higher configurational enthalpy, by as much as 42 J g⁻¹. Thermomechanical analysis (TMA) results indicate that the glassy materials undergo a glass transition at around 50 °C, during which a transformation from a rigid to a liquid‐like state occurs. The glasses showed a tendency to crystallize, as was observed with TMA and DSC analysis. It was observed that the stability of the amorphous phase with respect to crystallization improved with increasing pellet density. These findings serve to highlight the unique opportunity presented by glassy energetics to achieve improvements beyond those attainable with traditional crystalline materials.     

Electrocatalytic tandem Knoevenagel-Michael reaction of 3-methyl-2-pyrazolin-5-ones, aryl aldehydes and cyano-functionalized C-H acids: Facile and convenient multicomponent way to substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles

Electrochemically induced catalytic tandem Knoevenagel-Michael reaction of 3-methyl-2-pyrazolin-5-ones, aryl aldehydes and malononitrile or alkyl cyanoacetates in alcohols in an undivided cell in the presence of sodium bromide as an electrolyte results in the formation of substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles in 75-97% yields. The developed efficient electrocatalytic approach to the corresponding 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles is beneficial from the viewpoint of diversity-oriented large-scale processes and represents novel, facile and environmentally benign synthetic concept for multicomponent reactions strategy.     

Phase Stability and Ionic Conductivity of Solid Solutions with NASICON Structure

Formation of heterovalent Zr-substituted solid solutions (up to 7 mol%) for Yb³⁺ in Na₆Yb₃(PO₄)₅ and LiNa₅Yb₃(PO₄)₅ complex phosphates was studied by ceramic technique at 950°C. Obtained samples were investigated with X-ray powder diffraction, infrared, and impedance spectroscopy. Zr-substituted (7 mol%) Na₆Yb₃(PO₄)₅ has ionic conductivity of 1.6·10⁻² S/cm at 300°C and 4.8·10⁻⁵ S/cm at room temperature. An updated version of phase diagram for ScPO₄–Na₃PO₄–Li₃PO₄ quasi-ternary system was provided.     

Population Analysis of Diospyros lotus in the Northwestern Caucasus Based on Leaf Morphology and Multilocus DNA Markers

Diospyros lotus is the one of the most frost-tolerant species in the Diospyros genera, used as a rootstock for colder regions. Natural populations of D. lotus have a fragmented character of distribution in the Northwestern Caucasus, one of the coldest regions of Diospyros cultivation. To predict the behavior of D. lotus populations in an extreme environment, it is necessary to investigate the intraspecific genetic diversity and phenotypic variability of populations in the colder regions. In this study, we analyzed five geographically distant populations of D. lotus according to 33 morphological leaf traits, and the most informative traits were established, namely, leaf length, leaf width, leaf index (leaf to length ratio) and the length of the fourth veins. Additionally, we evaluated the intraspecific genetic diversity of D. lotus using ISSR and SCoT markers and proposed a new parameter for the evaluation of genetic polymorphism among populations, in order to eliminate the effect of sample number. This new parameter is the relative genetic polymorphism, which is the ratio of polymorphism to the number of samples. Based on morphological and genetic data, the northernmost population from Shkhafit was phenotypically and genetically distant from the other populations. The correspondence between several morphological traits (leaf width, leaf length and first to fifth right vein angles) and several marker bands (SCoT5, SCoT7, SCoT30: 800–1500 bp; ISSR13, ISSR14, ISSR880: 500–1000 bp) were observed for the Shkhafit population. Unique SCoT and ISSR fragments can be used as markers for breeding purposes. The results provide a better understanding of adaptive mechanisms in D. lotus in extreme environments and will be important for the further expansion of the cultivation area for persimmon in colder regions.     

Inhibitory Response to CK II Inhibitor Silmitasertib and CDKs Inhibitor Dinaciclib Is Related to Genetic Differences in Pancreatic Ductal Adenocarcinoma Cell Lines

Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2- and CDK-inhibitors have been considered as a therapeutic option, but are currently not part of routine chemotherapy regimens. We investigated ten PDAC cell lines exposed to increasing concentrations of silmitasertib and dinaciclib. Cell proliferation, metabolic activity, biomass, and apoptosis/necrosis were evaluated, and bioinformatic clustering was used to classify cell lines into sensitive groups based on their response to inhibitors. Furthermore, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) was conducted to assess recurrent mutations and the expression profile of inhibitor targets and genes frequently mutated in PDAC, respectively. Dinaciclib and silmitasertib demonstrated pronounced and limited cell line specific effects in cell death induction, respectively. WES revealed no genomic variants causing changes in the primary structure of the corresponding inhibitor target proteins. RNA-Seq demonstrated that the expression of all inhibitor target genes was higher in the PDAC cell lines compared to non-neoplastic pancreatic tissue. The observed differences in PDAC cell line sensitivity to silmitasertib or dinaciclib did not depend on target gene expression or the identified gene variants. For the PDAC hotspot genes kirsten rat sarcoma virus (KRAS) and tumor protein p53 (TP53), three and eight variants were identified, respectively. In conclusion, both inhibitors demonstrated in vitro efficacy on the PDAC cell lines. However, aberrations and expression of inhibitor target genes did not appear to affect the efficacy of the corresponding inhibitors. In addition, specific aberrations in TP53 and KRAS affected the efficacy of both inhibitors.