Microstructure and mechanical properties of bulk yttria-partially-stabilized zirconia

A commercially available bulk 4.5 mole percent yttria-(Y2O3) partially stabilized zirconia (PSZ) was studied by light microscopy, X-ray analysis, microhardness measurement, and fracture toughness testing. The growth of the precipitates and the phase transformations were studied as a function of aging in air at 1500 C. Aging curves were constructed for both the as received and the solution annealed and quenched materials; the curves showed hardness peaks at 1397 and 1517 Kg/sq mm respectively. The rectangular plate shaped tetragonal precipitates were found to have a 110 habit plane. A total of twelve different types of tetragonal precipitates were found. Grinding of the Y2O3 PSZ into powder did not cause a significant amount of metastable tetragonal precipitates to transform into the monoclinc phase, thus indicating that transformation toughening is not a significant mechanism for the material

Engineering Outreach Education Through Social Media

Familiarizing teachers and educators with Engineering and other related STEM fields is crucial in educating students, so ensuring teachers with access to these resources is important. The objective of this work is to identify ways to use social media to provide support to K – 12 educators interested in implementing engineering education with their students

Testing T Invariance in the Interaction of Slow Neutrons with Aligned Nuclei

The study of five-fold (P even, T odd) correlation in the interaction of slow polarized neutrons with aligned nuclei is a possible way of testing the time reversal invariance due to the expected enhancement of T violating effects in compound resonances. Possible nuclear targets are discussed which can be aligned both dynamically as well as by the "brute force" method at low temperature. A statistical estimation is performed of the five-fold correlation for low lying p wave compound resonances of the $^{121}$Sb, $^{123}$Sb and $^{127}$I nuclei. It is shown that a significant improvement can be achieved for the bound on the intensity of the fundamental parity conserving time violating (PCTV) interaction.Comment: 22 pages, 5 figures, published versio

Faktor-faktor yang Mendasari Pengambilan Keputusan Petani Tebu Bermitra dengan PG. Djatiroto

Bahan baku tebu di PG. Djatiroto diperoleh dari tebu milik sendiri (TS) dan tebu rakyat (TR) melaui sistem kemitraan kerjasama bagi hasil dengan petani. Penelitian bertujuan untuk: (1) mengetahui faktor-faktor yang mendasari pengambilan keputusan petani tebu bermitra dengan PG. Djatiroto, (2) perbedaan pendapatan petani tebu yang bermitra dan petani tebu yang tidak bermitra dengan PG. Djatiroto. Metode pengambilan contoh menggunakan Proportionate stratified random sampling. Data yang digunakan adalah data primer dan data sekunder. Data dianalisis menggunakan Regresi Logistik dan Independent sample t-test. Hasil penelitian menunjukkan: (1) faktor yang berpengaruh nyata terhadap pengambilan keputusan petani tebu bermitra dengan PG. Djatiroto adalah faktor pengalaman dengan nilai signifikansi sebesar 0,092, faktor pendapatan dengan nilai signifikansi sebesar 0,036, dan faktor jumlah anggota keluarga dengan nilai signifikansi sebesar 0,068 sedangkan faktor umur dan pendidikan berpengaruh tidak nyata terhadap pengambilan keputusan petani tebu bermitra dengan PG. Djatiroto; (2) terdapat perbedaan pendapatan antara petani tebu yang bermitra dan petani tebu yang tidak bermitra dengan PG. Djatiroto dengan nilai signifikansi sebesar 0,002, pendapatan petani tebu yang bermitra lebih besar dari pada pendapatan petani tebu yang tidak bermitra dengan PG. Djatiroto. Rata-rata pendapatan petani tebu yang bermitra sebesar Rp. 25.822.092/ha/tahun sedangkan rata-rata pendapatan petani tebu yang tidak bermitra sebesar RP. 20.010.176/ha/tahun

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

The synthesis of novel tetrahydroquinolines (THQ) and dihydroquinolines (DHQ) are reported using three practical, scalable synthetic approaches to access highly lipophilic analogues bearing a 6-iodo substituent, each with a different means of cyclisation. A versatile and stable quinolin-2-one intermediate was identified, which could be reduced to the corresponding THQ with borane reagents, or to the DHQ with diisobutylaluminium hydride via a novel elimination that is more favourable at higher temperatures. Coupling these strongly electron-donating scaffolds to electron-accepting moieties caused the resulting structures to exhibit strong fluorescence

Dynamical Bonding Driving Mixed Valency in a Metal Boride

Samarium hexaboride is an anomaly, having many exotic and seemingly mutually incompatible properties. It was proposed to be a mixed-valent semiconductor, and later - a topological Kondo insulator, and yet has a Fermi surface despite being an insulator. We propose a new and unified understanding of SmB$_6$ centered on the hitherto unrecognized dynamical bonding effect: the coexistence of two Sm-B bonding modes within SmB$_6$, corresponding to different oxidation states of the Sm. The mixed valency arises in SmB$_6$ from thermal population of these distinct minima enabled by motion of B. Our model simultaneously explains the thermal valence fluctuations, appearance of magnetic Fermi surface, excess entropy at low temperatures, pressure-induced phase transitions, and related features in Raman spectra and their unexpected dependence on temperature and boron isotope

Microrheology with optical tweezers: data analysis

We present a data analysis procedure that provides the solution to a long-standing issue in microrheology studies, i.e. the evaluation of the fluids' linear viscoelastic properties from the analysis of a finite set of experimental data, describing (for instance) the time-dependent mean-square displacement of suspended probe particles experiencing Brownian fluctuations. We report, for the first time in the literature, the linear viscoelastic response of an optically trapped bead suspended in a Newtonian fluid, over the entire range of experimentally accessible frequencies. The general validity of the proposed method makes it transferable to the majority of microrheology and rheology techniques

Judgements of Solomon: anxieties and defences of social workers involved in care proceedings

Evidence from focus group discussions with social workers in child care and child protection was collected for a research project exploring decision-making in care proceedings and seeking a better understanding of the causes of delay in the process. Here this material is used to examine social workers’ feelings about their work and to explore the anxieties they expressed. Isabel Menzies’s work on containing anxiety in institutions is used to provide a conceptual framework for thinking about the ways in which individuals’ unconscious defences against anxiety may affect the structure, policies and practices of the organization in which they work. It is suggested that this dimension needs to be taken into account in understanding difficulties which arise in putting policy into practice