Learning in multimodal training: Visual guidance can be both appealing and disadvantageous in spatial tasks

Multimodal training involving both visual and auditory information was shown to improve text comprehension and reduce cognitive load. However, it is argued that in spatial tasks visual guidance can impair training effectiveness because it encourages shallow performance strategies and little exploration. Moreover, visual aids are attractive to both trainers as well as trainees, who tend to use them despite their potential disadvantages. To examine this potential training trap, two experimental studies were conducted. In Study 1, each trainer instructed trainees on how to perform a 3-D puzzle in two conditions: vocal guidance (17 trainees), where only vocal instructions were possible, and vocal guidance with mouse pointing (17 trainees), where the trainer could also use a mouse to point out positions on the trainee's screen. The results showed that while the use of the mouse pointer reduced trainees' mental load during training, it also drastically lowered performance level on a non-supervised test. In Study 2, a real-world version of puzzle was trained. A comparison of a vocal guidance group (16 trainees) to a group trained with an additional mouse pointing and drawing option (16 trainees) showed, as well, reduced performance levels with the additional visual aids. The results suggest that the abundant use of multimodal training in Augmented Reality (AR) applications should be re-evaluated.     

Hybrid Nanostructures for Energy Storage Applications

Materials engineering plays a key role in the field of energy storage. In particular, engineering materials at the nanoscale offers unique properties resulting in high performance electrodes and electrolytes in various energy storage devices. Consequently, considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using these advanced materials. Various multi‐functional hybrid nanostructured materials are currently being studied to improve energy and power densities of next generation storage devices. This review describes some of the recent progress in the synthesis of different types of hybrid nanostructures using template assisted and non‐template based methods. The potential applications and recent research efforts to utilize these hybrid nanostructures to enhance the electrochemical energy storage properties of Li‐ion battery and supercapacitor are discussed. This review also briefly outlines some of the recent progress and new approaches being explored in the techniques of fabrication of 3D battery structures using hybrid nanoarchitectures.     

Synthesis and hydrogen storage properties of different types of boron nitride nanostructures

The present work reports the synthesis and hydrogen storage properties of different types of boron nitride (BN) nanostructures prepared by an in situ silica-assisted catalytic chemical vapor deposition technique. The BN nanostructures have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer, Emmett, and Teller (BET), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy studies. The hydrogen storage properties of BN nanostructures have been investigated using a high-pressure Seiverts' apparatus in the pressure range of 1–100 bar and at 298 K. The dependence of hydrogen storage capacity on the morphology of BN nanostructures is discussed in detail.     

Direct laser writing of micro-supercapacitors on hydrated graphite oxide films

Microscale supercapacitors provide an important complement to batteries in a variety of applications, including portable electronics. Although they can be manufactured using a number of printing and lithography techniques, continued improvements in cost, scalability and form factor are required to realize their full potential. Here, we demonstrate the scalable fabrication of a new type of all-carbon, monolithic supercapacitor by laser reduction and patterning of graphite oxide films. We pattern both in-plane and conventional electrodes consisting of reduced graphite oxide with micrometre resolution, between which graphite oxide serves as a solid electrolyte. The substantial amounts of trapped water in the graphite oxide makes it simultaneously a good ionic conductor and an electrical insulator, allowing it to serve as both an electrolyte and an electrode separator with ion transport characteristics similar to that observed for Nafion membranes. The resulting micro-supercapacitor devices show good cyclic stability, and energy storage capacities comparable to existing thin-film supercapacitors.     

Building energy storage device on a single nanowire

Hybrid electrochemical energy storage devices combine the advantages of battery and supercapacitors, resulting in systems of high energy and power density. Using LiPF(6) electrolyte, the Ni-Sn/PANI electrochemical system, free of Li-based electrodes, works on a hybrid mechanism based on Li intercalation at the anode and PF(6)(-) doping at the cathode. Here, we also demonstrate a composite nanostructure electrochemical device with the anode (Ni-Sn) and cathode (polyaniline, PANI) nanowires packaged within conformal polymer core-shell separator. Parallel array of these nanowire devices shows reversible areal capacity of ～3 μAh/cm(2) at a current rate of 0.03 mA/cm(2). The work shows the ultimate miniaturization possible for energy storage devices where all essential components can be engineered on a single nanowire.     

Synthesis and electrocatalytic oxygen reduction activity of graphene-supported Pt3Co and Pt3Cr alloy nanoparticles

Graphene-supported Pt and Pt₃M (M = Co and Cr) alloy nanoparticles are prepared by ethylene glycol reduction method and characterized with X-ray diffraction and transmission electron microscopy. X-ray diffraction depicted the face-centered cubic structure of Pt in the prepared materials. Electron microscopic images show the high dispersion of metallic nanoparticles on graphene sheets. Electrocatalytic activity and stability of the materials is investigated by rotating-disk electrode voltammetry. Oxygen reduction activity of the Pt₃M/graphene is found to be 3–4 times higher than that of Pt/graphene. In addition, Pt₃M/graphene electrodes exhibited overpotential 45–70 mV lower than that of Pt/graphene. The high catalytic performance of Pt₃M alloys is ascribed to the inhibition of formation of (hydr) oxy species on Pt surface by the alloying elements. The fuel cell performance of the catalysts is tested at 353 K and 1 atm. Maximum power densities of 790, 875, and 985 mW/cm² are observed with graphene-supported Pt, Pt₃Co, and Pt₃Cr cathodes, respectively. The enhanced electrocatalytic performance of the Pt₃M/graphene (M = Co and Cr) compared to that of Pt/graphene makes them a viable alternative to the extant cathodes for energy conversion device applications.     

Intracystic tumors of the breast

The authors report their experience obtained on the diagnostics of intracystic breast tumours in the last five years. It can be stated that ultrasound is currently the most valuable supplementary imaging method for the diagnosis of this rarely observed tumour. With the aid of ultrasonography, guided sampling can easily be carried out, and hence the preoperative diagnostic accuracy is increased. Pneumocystography is needed only in special cases.     

3D nanoporous nanowire current collectors for thin film microbatteries

Conventional thin film batteries are fabricated based on planar current collector designs where the high contact resistance between the current collector and electrodes impedes overall battery performance. Hence, current collectors based on 3D architectures and nanoscale roughness has been proposed to dramatically increase the electrode-current collector surface contact areas and hence significantly reduce interfacial resistance. The nanorod-based current collector configuration is one of several 3D designs which has shown high potential for the development of high energy and high power microbatteries in this regard. Herein we fabricate a nanoporous nanorod based current collector, which provides increased surface area for electrode deposition arising from the porosity of each nanorods, yet keeping an ordered spacing between nanorods for the deposition of subsequent electrolyte and electrode layers. The new nanostructured 3D current collector is demonstrated with a polyaniline (PANI)-based electrode system and is shown to deliver improved rate capability characteristics compared to planar configurations. We have been able to achieve stable capacities of ~32 μAh/cm(2) up to 75 cycles of charge/discharge even at a current rate of ~0.04 mA/cm(2) and have observed good rate capability even at high current rates of ~0.8 mA/cm(2).     

Eppur si Muove: Proton Diffusion in Halide Perovskite Single Crystals

Ion diffusion affects the optoelectronic properties of halide-perovskites (HaPs). Until now, the fastest diffusion has been attributed to the movement of the halides, largely neglecting the contribution of protons, on the basis of computed density estimates. Here, the process of proton diffusion inside HaPs, following deuterium–hydrogen exchange and migration in MAPbI₃, MAPbBr₃, and FAPbBr₃ single crystals, is proven through D/H NMR quantification, Raman spectroscopy, and elastic recoil detection analysis, challenging the original assumption of halide-dominated diffusion. The results are confirmed by impedance spectroscopy, where MAPbBr₃- and CsPbBr₃-based solar cells respond at very different frequencies. Water plays a key role in allowing the migration of protons as deuteration is not detected in its absence. The water contribution is modeled to explain and forecast its effect as a function of its concentration in the perovskite structure. These findings are of great importance as they evidence how unexpected, water-dependent proton diffusion can be at the basis of the ≈7 orders of magnitude spread of diffusion (attributed to I⁻ and Br⁻) coefficient values, reported in the literature. The reported enhancement of the optoelectronic properties of HaP when exposed to small amounts of water may be related to the finding.