Using tangible user interfaces in computer-based training systems for low-functioning autistic children

In this paper, the design of a computer-based training (CBT) system for low-functioning autistic children is addressed. The emphasis is on ease-of-use and learning efficiency of CBT systems with different interaction styles, namely the WIMP (Window Icon Menu Pointing Device) and TUI (Tangible User Interface) interaction styles. Two WIMP-based CBT systems with different pointing devices were involved in the study. The first system applied a standard computer mouse as a pointing device, while the second one employed a touch screen instead. For the TUI-based CBT system, a tabletop setting was adopted. Based on the known characteristics of TUI and children with autism, as well as related cognitive and learning theories, the benefits of TUI for low-functioning autistic children have been investigated. Elementary skill teaching was chosen as a case study for performance evaluation of these CBT systems. Empirical results show that the touch-based and TUI-based systems offered much better ease-of-use performance than that of the mouse-based system. Regarding learning efficacy, experimental results show that the TUI-based system achieved higher skill improvement, as compared with the WIMP-based system and a non-computer training method. Some guidelines and suggestions for the design of a TUI-based system for children with autism are summarized.     

Hydrogen adsorption of O/N-rich hierarchical carbon scaffold decorated with Ni nanoparticles: Experimental and computational studies

Hierarchical carbon scaffold (HCS) with multi-porous structures, favoring hydrogen diffusion and physisorption is doped with 2–10 wt % Ni for storing hydrogen at ambient temperature. Due to N- and O-rich structure of melamine-formaldehyde resin used as carbon precursor, homogeneous distribution of heteroatoms (N and O) in HCS is achieved. 2 wt % Ni-doped HCS shows the highest hydrogen capacity up to 2.40 wt % H₂ (T = 298 K and p (H₂) = 100 bar) as well as excellent reversibility of 18.25 g H₂/L and 1.25 wt % H₂ (T = 298 K and p (H₂) = 50 bar) and electrical production from PEMFC stack up to 0.7 Wh upon eight cycles. Computations and experiments confirm strong interactions between Ni and heteroatoms, leading to uniform distribution small particles of Ni. This results in enhancing reactive surface area for hydrogen adsorption and preventing agglomeration of Ni nanoparticles upon cycling. Ni K-edge XANES spectra simulated from the optimized structure of Ni-doped N/O-rich carbon using DFT calculations are consistent with the experimental spectra and suggest electron transfer from Ni to hydrogen to form Ni–H bond upon adsorption. Considering low desorption temperature (323 K), not only chemisorbed hydrogen is involved in adsorption mechanisms but also physisorption and spillover of hydrogen.     

<Emphasis Type="SmallCaps">d</Emphasis>-Maltose Synthesized Silver Nanoparticles for Biofilm Eradication

Biofilms are complex bacterial communities have a mechanism for antibiotic resistance leading to human health problems. It remains challenging to treat and eradicate biofilms. In this work, the use of d-maltose synthesized silver nanoparticles (AgNPs) was investigated in an effort to eradicate a biofilm. AgNPs were synthesized using a modified Tollen’s method. d-maltose was used in synthesizing AgNPs with different concentrations of d-maltose (0.01, 0.05 and 0.1 M), referred to as NP1, NP2 and NP3, respectively. TEM images revealed that the particles were polygon shaped. The particle sizes were found to be 86.81?±?13.39, 54.94?±?11.63 and 31.43?±?31.76 nm depending on their sugar concentrations. UV–Vis, ATR–FTIR, and XRD patterns were employed to characterize the AgNPs. Then, these AgNPs were investigated for their anti-bacterial effects against Escherichia coli and Staphylococcus aureus. Evaluation of the minimum inhibitory concentration and minimal bactericidal concentration revealed that S. aureus was inhibited by all AgNPs and killed by NP1 and NP3, and E. coli was inhibited and killed at all AgNPs doses. Furthermore, anti-biofilm activity against these two bacteria was observed using SEM and confocal laser scanning microscopy. This sugar coated AgNPs is a promising material for use in eradication of biofilms.     

Sequential fermentation of hydrogen and methane from steam-exploded sugarcane bagasse hydrolysate

The goal of this study was to sequential fermentation of hydrogen and methane from sugarcane bagasse (SCB). Steam explosion conditions for pretreating SCB were optimum at 195 °C and 1.5 min, which yielded 36.35 g/L of total sugar and 2.35 g/L of total inhibitors. Under these conditions (all in g/L): glucose, 11.33; xylose, 24.41; arabinose, 0.61; acetic acid, 2.33; and furfural, 0.02 were obtained. The resulting hydrolysate was used to produce hydrogen by anaerobic mixed cultures. A maximum hydrogen production rate of 396.50 mL H₂/L day was achieved at an initial pH of 6 and an initial total sugar concentration of 10 g/L. The effluent from the hydrogen fermentation process was further used to produce methane. Response surface methodology with central composite design was used to obtain the suitable conditions for maximizing methane production rate (MPR). An MPR of 185.73 mL/L day was achieved at initial pH, Ni and Fe concentrations of 7.59, 3.61 mg/L and 8.44 mg/L, respectively. Total energy of 304.11 kJ/L-substrate was obtained from a sequential fermentation of hydrogen and methane. This approach will not only add value to SCB, in the form of safe and clean energy, but also provide a solution for making use of this abundant waste.     

Synthesis and antifungal activity of reduced graphene oxide nanosheets

Reduced graphene oxide (rGO) nanosheets were produced using a modified Hummers method. Antifungal activity of rGO nanosheets was tested against three fungi i.e., Aspergillus niger (A. niger), Aspergillus oryzae (A. oryzae) and Fusarium oxysporum (F. oxysporum). The rGO inhibits the mycelial growth of the fungi and it is believed that this is due to its sharp edges. The half maximal inhibitory concentration (IC₅₀), a measure of the effectiveness of the rGO in inhibiting the fungi, was investigated. IC₅₀ values of the rGO against F. oxysporum, A. niger, and A. oryzae are 50, 100, and 100 μg ml^?1, respectively.     

A memetic algorithm-based heuristic for a scheduling problem in printed circuit board assembly

This research develops a memetic algorithm to solve Printed Circuit Board (PCB) scheduling with sequence-dependent setup times on a single machine with constrained feeder capacity. The objective of the scheduling problem is to minimize the total weighted tardiness. A memetic algorithm-based heuristics is developed by integrating a genetic algorithm, Minimum Slack Time (MST) scheduling rule, “Keep Tool Needed Soonest” (KTNS) policy, and a local search procedure. Application of the MA results in two outcome plans: a scheduling plan and a feeder setup plan.Numerical experiments show that compared to a number of commonly used dispatching rules, the memetic algorithm provides better solutions in term of minimum total weighted tardiness. Even the computation is the highest, it still practical. Calibration of MA parameter values is also explored in this study.     

Enhanced mechanical properties and bactericidal activity of polypropylene nanocomposite with dual‐function silica–silver core‐shell nanoparticles

Dual‐function silica–silver core‐shell (SiO₂@Ag) nanoparticles (NPs) with the core diameter of 17 ± 2 nm and the shell thickness of about 1.5 nm were produced using a green chemistry. The SiO₂@Ag NPs were tested in vitro against gram‐positive Staphylococcus aureus (S. aureus) and gram‐negative Escherichia coli (E. coli), both of which are human pathogens. Minimal inhibitory concentrations of the SiO₂@Ag NPs based on Ag content are 4 and 10 μg mL^?1 against S. aureus and E. coli, respectively. These values are similar to those of Ag NPs. SiO₂@Ag NPs were for the first time incorporated to a commodity polypropylene (PP) polymer. This yielded an advanced multifunctional polymer using current compounding technologies i.e., melt blending by twin‐screw extruder and solvent (toluene) blending. The composite containing 5 wt % SiO₂@Ag NPs (0.05 wt % Ag) exhibited efficient bactericidal activity with over 99.99% reduction in bacterial cell viability and significantly improved the flexural modulus of the PP. Anodic stripping voltammetry, used to investigate the antibacterial mechanism of the composite, indicated that a bactericidal Ag⁺ agent was released from the composite in an aqueous environment. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of the body position on natural convection within the anterior chamber of the human eye during exposure to electromagnetic fields

ABSTRACT

Heating is the main biological effect of the electromagnetic (EM) fields to human eye. This study intends to focus attention on the differences in the heat transfer characteristics of the human eye induced by EM fields in different body positions. The effect of three different body positions – sitting, supine, and prone – on natural convection of aqueous humor (AH) in the anterior chamber of the eye is systematically investigated. The specific absorption rate (SAR) value, fluid flow, and the temperature distribution in the eye during exposure to EM fields are obtained by numerical simulation of EM wave propagation. In this study, the frequencies of 900 and 1,800 MHz are chosen for the investigations. The heat transfer model used in this study is developed based on natural convection and porous media theories. The results show that the AH temperature inside the anterior chamber is the highest in the supine position at both frequencies. It is found that during exposure to EM fields, body position plays an important role on AH natural convection and the heat transfer process within the anterior chamber and its periphery in the front part of the eye. However, the body position has no significant effect on temperature distribution for the middle part of the eye. The obtained results provide information on the body position and thermal effects from EM fields exposure.