Testing of numerous hypotheses with the use of an optimal extended nonrandomized procedure

We propose a new procedure for testing hypotheses with the use of optimal statistical criteria. Institute of Cybernetics, Ukrainian Academy of Sciences, Kiev. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 49, No. 8, pp. 1042–1054, August, 1997.     

Solvothermal synthesis and luminescence properties of the novel aluminum garnet phosphors for WLED applications

The color rendering index (CRI) and structural stability of cerium doped yttrium aluminum garnet (YAG:Ce) based phosphors have been enhanced by replacing Y³⁺ ions by larger radius ions (Tb³⁺, Gd³⁺, Eu³⁺, and Sm³⁺) at the dodecahedral site and replacing Al³⁺ ions by larger ones (Ga³⁺, Y³⁺, Tb³⁺, Gd³⁺, and Sm³⁺) at the octahedral site. These aluminum garnet crystalline powders were prepared by solvothermal reaction method at 300 °C for 48 h. The lattice constant values of synthetic aluminum garnet crystalline powders are larger than that of YAG and the emission wavelength of Ce³⁺ ion of these samples is longer than that of YAG:Ce. FESEM and TEM studies revealed that the Ln₃Ga₂Al₃O₁₂ and Ln₃Al₂Al₃O₁₂ crystalline powders have 3-dimensional star-like morphology with submicron size and good crystallinity, while, Ln₃(LnAl)Al₃O₁₂ garnet crystalline powders were cubic crystalline phases and shaped as cubes with the round edge having an approximate diameter of about 200–400 nm. All the prepared powders were grown along (100) direction and crystallized into single crystal. Also, the effects of treatment time and reaction temperature on the structure of aluminum garnet crystalline powders have been investigated.     

Effect of Silica and Silicone Oil on the Mechanical and Thermal Properties of Silicone Rubber

The effect of three types of silicas with varied loading and the loading of hydroxyl terminated silicone oil on the mechanical and thermal properties of silicone rubbers (SRs) were investigated. Mechanical properties were affected by the silica loading because of the interaction between fillers and polymer and the filler dispersion. Fumed silica filled SRs showed higher tanδ, tensile strength, and elongation at break compared to those containing two types of precipitated silicas. With increasing silicone oil loading, the tensile strength, tear strength, hardness, and tanδ of SRs first increased and then decreased.     

Study on Thermoplastic Elastomers (TPEs) of Waste Polypropylene/Waste Ground Rubber Tire Powder

Recycling represents a valid alternative to the disposal of postconsumer materials if it is possible to obtain new materials with good properties. In this work the possibility to produce secondary materials by blending waste polypropylene (WPP) and waste ground rubber tire powder (WGRT) was studied. Several comparative experiments were made to evaluate the influence of bitumen content and different compatibilizers on the properties of WPP/WGRT blends using a universal testing machine (UTM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and capillary rheometry. The results suggested that the properties of WPP/WGRT blends were dependent on the content of bitumen and the kind of compatibilizer.     

Cesium-filled single wall carbon nanotubes as conducting nanowires: scanning tunneling spectroscopy study

Metal-filled single wall carbon nanotubes (SWCNTs) are examined for possible application to conducting wires in nanoelectronics architecture. The local electronic structure of SWCNTs partially filled with cesium atoms is studied with scanning tunneling spectroscopy. The conduction and valence bands are shifted downward with two localized states in the gap at the location where the Cs atoms are filled. From a first-principles calculation, we confirm that these two gap states are bound states originating from the two lowest conduction bands.     

Redox behavior of cyclo[6]pyrrole in the formation of a uranyl complex

A uranyl complex, the first metal complex to be formed from the cyclo[n]pyrrole series of expanded porphyrins, is formed when cyclo[6]pyrrole is treated with the uranyl cation under aerobic conditions. Spectroscopic, spectroelectrochemical, and electron spin resonance data of this species are consistent with the ligand in the complex being oxidized to an antiaromatic form.     

A color version of the Hinsberg test: 1 degrees -3 degrees amine indicator

The Hinsberg test to recognize the type of amine (1 degrees -3 degrees amines), which has been established for more than 100 years and well documented in textbooks, is not possible without conducting complicated organic reactions. We report for the first time unique chemosensors that are capable of showing selective color changes toward 1 degrees -3 degrees amines as a color version of the Hinsberg test. This simple and straightforward qualitative analysis, using the synthesized novel compounds herein, can be considered a new innovative tool for discriminating 1 degrees -3 degrees amines as an alternative to the historical Hinsberg test.     

Improvement of the stability of NiO–YSZ anode material for solid oxide fuel cell

Improvement of long-term stability of 40vol.%NiO–60vol.% yttria-stabilized zirconia (YSZ) anode material in reducing atmosphere and under exposure to thermal shock through the modification of vacancy concentration and pore shape has been investigated for a solid oxide fuel cell. We varied the amount of Y₂O₃ additives from 8 to 10 mol% in YSZ and the type of carbon pore former, from plated activated carbon to spherical carbon black, to improve the strength and the stability of porous NiO–YSZ anode materials. Modifications by varying the amount of Y₂O₃ additives and carbon pore former result in a highly stable anode, even upon exposure to a reducing atmosphere for 1,200 h. In particular, the strengths of the new anode materials are markedly improved at the same porosity level. Higher strengths do not degrade during a longtime durability test in a reducing atmosphere or upon thermal shock testing. The relatively smaller degradation of electrical conductivity of the new anode material is discussed in terms of the possibility of suppression of the disconnectivity of Ni phases during operation of a solid oxide fuel cell.