Effects of age, speech rate, and environmental support in using telephone voice menu systems

Age differences in the use of telephone menu systems were investigated in two experiments. Participants from three age groups (younger: 18-39; middle-aged: 40-59; older: 60+ years) were required to obtain specified information or perform some action using simulated voice menu systems. Measures reflecting task performance, menu navigation, and subjective responses were collected. The focus in Experiment 1 was on examining the effect of speech rate. Data from 196 participants indicated age differences in performance, especially for complex problems. There was no effect of speech rate on any of the performance measures. Experiment 2 examined two types of support devices: a screen phone and a graphical aid. Data from 114 participants indicated that the screen phone provided some benefits in navigational efficiency. In terms of performance, the older participants benefited more from the graphical aid and the younger participants performed better with the screen phone. Actual or potential applications of this research include guidance in the use of support devices that can reduce memory demands and the identification of appropriate speech rates.     

Static and dynamic fracture toughness of a medium carbon microalloyed steel of three different microstructures

A multiphase ferrite-bainite-martensite (F-B-M) microstructure was developed in an automotive grade V-bearing medium carbon microalloyed steel, 38MnSiVS5. It was characterized using optical, scanning, and transmission electron microscopy. The tensile, Charpy impact, and static and dynamic fracture toughness behaviors were evaluated. The results are compared with those of ferrite-pearlite (F-P) and tempered martensite (T-M) microstructures of the same steel. Although the tensile properties of the multiphase microstructures were superior, the Charpy impact and static and dynamic fracture toughness properties were inferior compared with those of the other two microstructures. The F-P condition displayed the highest plane strain fracture toughness value (K_IC), while the T-M condition was characterized by the highest dynamic fracture toughness (conditional) value (K_IDQ). The Charpy impact energy of the T-M condition was greater than that for the other two conditions. An examination of the surfaces of fractured samples revealed predominant ductile crack growth in the F-P microstructure and a mixed mode (ductile and brittle) crack growth in the T-M and the F-B-M microstructures. Although the Charpy impact energy, plane fracture toughness (K_IC), and conditional dynamic fracture toughness (K_IDQ) of the multiphase microstructure were inferior to those of the T-M and the F-P microstructures, the toughness properties were comparable to those of medium carbon low alloy steels having bainite-martensite (AISI 4340) or tempered martensite microstructures.     

Controlled insulator-to-metal transformation in printable polymer composites with nanometal clusters

Although organic semiconductors have received the most attention, the development of compatible passive elements, such as interconnects and electrodes, is also central to plastic electronics. For this, ligand-protected metal-cluster films have been shown to anneal at low temperatures below 250 degrees C to highly conductive metal films, but they suffer from cracking and inadequate substrate adhesion. Here, we report printable metal-cluster-polymer nanocomposites that anneal to a controlled-percolation nanostructure without complete sintering of the metal clusters. This overcomes the previous challenges while still retaining the desired low transformation temperatures. Highly water- and alcohol-soluble gold clusters (75 mg ml-1) were synthesized and homogeneously dispersed into poly(3,4-ethylenedioxythiophene) to give a material with annealed d.c. conductivity tuneable between 10(-4) and 10(5) S cm-1. These composites can inject holes efficiently into all-printed polymer organic transistors. The insulator-metal transformation can also be electrically induced at 1 MV cm-1, suggesting possible memory applications.     

Origins of the long-range exciton diffusion in perovskite nanocrystal films: photon recycling vs exciton hopping

The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion properties.As the perovskite material dimensionality is reduced to exploit the quantum confinement effects,the disruption to the perovskite lattice,often with insulating organic ligands,raises new questions on the charge diffusion properties.Herein,we report direct imaging of>1μm exciton diffusion lengths in CH3NH3PbBr3 perovskite nanocrystal(PNC)films.Surprisingly,the resulting exciton mobilities in these PNC films can reach 10±2cm²V^-1 s^-1,,which is counterintuitively several times higher than the carrier mobility in 3D perovskite films.We show that this ultralong exciton diffusion originates from both efficient inter-NC exciton hopping(via Forster energy transfer)and the photon recycling process with a smaller yet significant contribution.Importantly,our study not only sheds new light on the highly debated origins of the excellent exciton diffusion in PNC films but also highlights the potential of PNCs for optoelearonic applications.     

Biochar from oil cakes: an efficient and economical adsorbent for the removal of acid dyes from wool dye house effluent

Clean Technologies and Environmental Policy - In the reported study, biochars were prepared from almond, coconut, and mustard oil cakes by chemical activation with phosphoric acid followed by...     

Microplasmas for Advanced Materials and Devices

Microplasmas are low-temperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Here, recent microplasma applications are examined, spanning from high-throughput, printing-technology-compatible synthesis of nanocrystalline particles of common materials types, to water purification and optoelectronic devices. Microplasmas combined with gaseous and/or liquid media at low temperatures and atmospheric pressure open new ways to form advanced functional materials and devices. Specific examples include gas-phase, substrate-free, plasma-liquid, and surface-supported synthesis of metallic, semiconducting, metal oxide, and carbon-based nanomaterials. Representative applications of microplasmas of particular importance to materials science and technology include light sources for multipurpose, efficient VUV/UV light sources for photochemical materials processing and spectroscopic materials analysis, surface disinfection, water purification, active electromagnetic devices based on artificial microplasma optical materials, and other devices and systems including the plasma transistor. The current limitations and future opportunities for microplasma applications in materials related fields are highlighted.     

A Quick Route to Multiple Highly Potent SARS-CoV-2 Main Protease Inhibitors**

The COVID-19 pathogen, SARS-CoV-2, requires its main protease (SC2M^Pro) to digest two of its translated long polypeptides to form a number of mature proteins that are essential for viral replication and pathogenesis. Inhibition of this vital proteolytic process is effective in preventing the virus from replicating in infected cells and therefore provides a potential COVID-19 treatment option. Guided by previous medicinal chemistry studies about SARS-CoV-1 main protease (SC1M^Pro), we have designed and synthesized a series of SC2M^Pro inhibitors that contain β-(S-2-oxopyrrolidin-3-yl)-alaninal (Opal) for the formation of a reversible covalent bond with the SC2M^Pro active-site cysteine C145. All inhibitors display high potency with K_i values at or below 100 nM. The most potent compound, MPI3, has as a K_i value of 8.3 nM. Crystallographic analyses of SC2M^Pro bound to seven inhibitors indicated both formation of a covalent bond with C145 and structural rearrangement from the apoenzyme to accommodate the inhibitors. Virus inhibition assays revealed that several inhibitors have high potency in inhibiting the SARS-CoV-2-induced cytopathogenic effect in both Vero E6 and A549/ACE2 cells. Two inhibitors, MPI5 and MPI8, completely prevented the SARS-CoV-2-induced cytopathogenic effect in Vero E6 cells at 2.5–5 μM and A549/ACE2 cells at 0.16–0.31 μM. Their virus inhibition potency is much higher than that of some existing molecules that are under preclinical and clinical investigations for the treatment of COVID-19. Our study indicates that there is a large chemical space that needs to be explored for the development of SC2M^Pro inhibitors with ultra-high antiviral potency.     

Performance analysis of ONU-wavelength grouping schemes for efficient scheduling in long reach-PONs

Long Reach PONs (LR-PON) were proposed to extend the benefits of Passive Optical Networks (PON) to more users and to a larger area. This paper considers a Dynamic Bandwidth Allocation (DBA) based on a hybrid combination of Time Division Multiplexing (TDM) and Wavelength Division Multiplexing (WDM). The time complexity of the DBA algorithm is typically O(n log n), where n denotes the number of ONUs. Since the maximum number of supported ONUs in an LR-PON can be as high as 2048, the computation time required for computing a schedule will be very high and directly impacts the overall network performance. In this paper, we have presented a grouping strategy to reduce the computation requirements. The number of ONUs is split into mutually exclusive groups with the OLT scheduling each group independently and in parallel. With the static grouping strategy every user is assigned to a group and the assignment of wavelength resources is fixed. However, with non-uniform loads, we observed that static grouping was not found to be suitable as the delay variation was significant across the groups. To address this gap, we introduce the concept of dynamic grouping and define three dynamic grouping heuristics that adapt to the current network load conditions and (re)allocate the ONUs and wavelength resources suitably. The proposed schemes have been compared in terms of delay variation and wavelength utilization. Of the three heuristics, ONU to Least Loaded wavelength group (OLL) and Least Wavelength Resources (LWR) heuristics balance the packet delay across ONUs assigned to different groups and Proportional Wavelength Usage (PWU) heuristic reduces power consumption by allocating fewer wavelength resources.     

Tuning mesoporous molecular sieve SBA-15 for the immobilization of α-amylase

The present work describes the immobilization of α-amylase over well ordered mesoporous molecular sieve SBA-15 with different pore diameters synthesized by post synthesis treatment (PST) hydrothermally after reaction at 40°C. The materials were characterized by N₂ adsorption–desorption studies, small angle X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy. Since α-amylase obtained from Bacillus subtilis has dimensions of 35 × 40 × 70 Å it is expected that the protein have access to the pore of SBA-15 (PST-120°C) with diameter 74 Å. The pore dimension is appropriate to prevent considerable leaching. The rate of adsorption of the enzyme on silica of various pore sizes revealed the influence of morphology, pore diameter, pore volume and pH.