The indentation size effect of sintered Fe/3.3 wt-%Cu + CnHm measured by Vickers scale

ABSTRACT

The aim of the submitted work is to study the influence of applied loads (test forces) between 0.09807 and 2.9421?N on the measured value of micro-hardness of sintered Fe/3.3?wt-%Cu?+?C_nH_m. The Indentation Size Effect (ISE), i.e. the influence of the load on the micro-hardness is expected. The results were evaluated by Meyer’s index n, t-test, and non-parametric tests. The applied load has a statistically significant influence on the type and size of the ISE. Tested sintered material shows ‘normal’ ISE with Meyer’s index n?=?1.7588.     

Experimental investigation and thermodynamic prediction of the Bi–Sb–Zn phase diagram

Phase diagram of the ternary Bi–Sb–Zn system was investigated experimentally by DTA and SEM-EDS methods and analytically by CALPHAD method. The liquidus projection, invariant equilibria, several vertical sections and isothermal section at 300 °C were predicted using COST 531 thermodynamic database. Phase transition temperatures of alloys along three predicted vertical sections of the Bi–Sb–Zn ternary system with molar ratio Bi:Sb = 1, Bi:Zn = 1 and Sb:Zn = 1, were measured by differential thermal analysis (DTA). Predicted isothermal section at 300 °C was compared with the results of the scanning electron microscope (SEM) with energy dispersive spectrometry (EDS) analysis from this work.     

Fluorescent Nanodiamonds Embedded in Biocompatible Translucent Shells

High pressure high temperature (HPHT) nanodiamonds (NDs) represent extremely promising materials for construction of fluorescent nanoprobes and nanosensors. However, some properties of bare NDs limit their direct use in these applications: they precipitate in biological solutions, only a limited set of bio‐orthogonal conjugation techniques is available and the accessible material is greatly polydisperse in shape. In this work, we encapsulate bright 30‐nm fluorescent nanodiamonds (FNDs) in 10–20‐nm thick translucent (i.e., not altering FND fluorescence) silica shells, yielding monodisperse near‐spherical particles of mean diameter 66 nm. High yield modification of the shells with PEG chains stabilizes the particles in ionic solutions, making them applicable in biological environments. We further modify the opposite ends of PEG chains with fluorescent dyes or vectoring peptide using click chemistry. High conversion of this bio‐orthogonal coupling yielded circa 2000 dye or peptide molecules on a single FND. We demonstrate the superior properties of these particles by in vitro interaction with human prostate cancer cells: while bare nanodiamonds strongly aggregate in the buffer and adsorb onto the cell membrane, the shell encapsulated NDs do not adsorb nonspecifically and they penetrate inside the cells.     

3D Printing of Customized Drug Delivery Systems with Controlled Architecture via Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing via reversible addition-fragmentation chain transfer (RAFT) polymerization has been recently developed to expand the scope of 3D printing technologies. A potentially high-impact but relatively unexplored opportunity that can be provided by RAFT-mediated 3D printing is a pathway toward personalized medicine through manufacturing bespoke drug delivery systems (DDSs). Herein, 3D printing of drug-eluting systems with precise geometry, size, drug dosage, and release duration/profiles is reported. This is achieved through engineering a range of 3D models with precise interconnected channel-pore structure and geometric proportions in architectural patterns. Notably, the application of the RAFT process is crucial in manufacturing materials with highly resolved macroscale features by confining curing to exposure precincts. This approach also allows spatiotemporal control of the drug loading and compositions within different layers of the scaffolds. The ratio between the polyethylene glycol units and the acrylate units in the crosslinkers is found to be a critical factor, with a higher ratio increasing swelling capacity, and thus enhancing the drug release profile, from the drug-eluting systems. This proof-of-concept research demonstrates that RAFT-mediated 3D printing enables the production of personalized drug delivery materials, providing a pathway to replace the “one-size-fits-all” approach in traditional health care.     

Thermal conductivity of ME771 glass-epoxy laminate from millikelvin temperatures to 4 K

Permaglas ME771 is a glass-epoxy laminate which is suitable for use at cryogenic temperatures. We have measured the thermal conductivity of a sample of this material between 64 mK and 4.2 K in the direction parallel to the reinforcing fibres, enabling us to make a comparison with the better known material G-10CR. The thermal conductivity follows the form that would be expected for such a material, and is similar to that of G-10CR, which has a similar (room temperature) tensile strength. We comment on some confusion that has arisen over the difference between G-10CR, a material specifically produced for cryogenic use, and G-10, the more common equivalent.     

Neuroindices of cognitive workload: Neuroimaging,pupillometric and event-related potential studies of brain work

This article is a selective theory-driven review that synthesizes recent neuroscience findings concerning mental workload during complex cognition from the perspective of a functional resource theory called 3CAPS, focusing on the concept of capacity utilization . Capacity utilization refers to the proportion of resources that is being consumed in a given time interval in a given cognitive system. This definition integrates the dynamic effects of (a) the computational demand imposed by a task, and (b) the resource supply in an individual that is available to meet that demand. The analysis reveals that the functional relations between capacity utilization and measures of neural activity are similar across three different cognitive systems (language comprehension, visuospatial processing and executive processing). The measures of neural activity include functional neuroimaging, pupillary dilation and event-related potentials. The construct of capacity utilization provides a mapping between a functional architecture of cognition and aspects of its neural implementation.     

Cluttered writing: adjectives and adverbs in academia

Scientific writing is about communicating ideas. Today, simplicity is more important than ever. Scientist are overwhelmed with new information. The overall growth rate for scientific publication over the last few decades has been at least 4.7 % per year, which means doubling publication volume every 15 years. I measure simplicity/readability with proportion of adjectives and adverbs in a paper, and find natural science to be the most readable and social science the least readable.     

Phonon-Based Position Determination in SuperCDMS iZIP Detectors

SuperCDMS is currently operating a 10-kg array of cryogenic germanium detectors in the Soudan Underground Laboratory to search for weakly interacting massive particles, a leading dark matter candidate. These detectors, known as iZIPs, measure ionization and athermal phonons from particle interactions with sensors on both sides of a Ge crystal. The ionization signal can be used to efficiently tag events at high radius and near the top and bottoms surfaces, where diminished charge collection can cause events to mimic WIMP-induced nuclear recoils. Using calibration data taken with a \(^{206}\) Pb source underground at Soudan, we demonstrate rejection of surface events of \((4.5 \pm 0.9) \times 10^{-4}\) with 46 % acceptance of nuclear recoils using the phonon signal only. We also show with \(^{133}\) Ba calibration data underground that the phonon channels can efficiently identify events near the sidewall. This phonon-based approach can also be extended to lower energies than the ionization-based position reconstruction.     

Heat-insulating composite based on unwoven materials and organomineral binder

Composites based on unwoven cellulose-hydrate and carbon materials and an organomineral binder have been developed and investigated. Optimal compositions of the composites feature a higher fire resistance, a low density, and effective thermophysical characteristics. The composites are promising for use as heat-insulating materials with a rigid structure in different branches of the national economy and industry. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 1, pp. 85–91, January–February, 2009.