The quality of the shell coating around nanorods is critical in device applications. Conventional physical vapor deposition (PVD) techniques can be utilized for highly conformal shell coating formation in core-shell structure devices. To identify scalable fabrication techniques for conformal shell coatings, Monte Carlo (MC) simulations of PVD growth were performed under different atomic flux distributions and angles on arrays of glancing angle deposition (GLAD) nanorods, which were also generated by MC simulations. We investigated the conformality of PVD films (shell) around GLAD rod arrays (core) and analyzed the thickness uniformity of the shell layer across the sidewalls of rods. Our results show that Angular Flux-Normal Angle (A-NAD), which might correspond to high-pressure sputter deposition at normal incidence (HIPS at θ = 0o) can generate better conformal shell coating compared to others. In Uniform Flux-Normal Angle technique (U-NAD), which corresponds to a thermal evaporation deposition, the growth suffers from poor sidewall coverage. In addition, introducing a small angle to the flux also improves the shell conformality. Therefore, high-pressure sputter deposition technique is expected to provide superior conformality for a catalyst or semiconductor coating around base nanorods, for example for fuel cell and solar cell applications, with the help of obliquely incident atoms of the HIPS flux.

Studies have shown that local laser heating/“drilling” of composite large-porous ceramics consisting of aluminosilicates and glass phase is based on melting and ablation processes that lead to the formation of holes in a porous specimen. The interaction of the components of the composite in the high-temperature heating zone is accompanied by the formation of glass-phase melt of new composition. The advance of the melt deep into the sample along channel-like pores of the main ceramic material depends on the viscosity of the melt (i.e., the irradiation mode) and the cooling rate of the melt (i.e., the thermo-physical properties of the ceramics and glass phase). The development of gas-dynamic impact in the laser heating zone leads not only to the ejection of a part of the melt from the channel, but also to the compaction of the ceramics adjacent to the walls of the vitrified channel. These effects depend heavily on the ceramic-to-glass phase ratio and the porosity of the initial ceramic. It has been established that “laser perforation” of highly porous aluminosilicate ceramics leads to the hardening of the coarse-porous ceramics due to the formation of holes with strong walls, consisting of layers of the glass phase and compacted ceramics in the sample.

We investigate the structure of neutral and charged bottlebrush polymers in salt-free solutions at different polymer concentrations. In particular, we use molecular dynamics simulations by utilizing a coarse-grained bead-spring model that includes an explicit solvent and complementary experiments made by small angle neutron scattering (SANS). We find that the charged groups along the side chains exert significant repulsive forces, resulting in polymer swelling and backbone stretching. In addition to the primary polyelectrolyte peak, we find that bottlebrush polymers exhibit an additional peak in the form and static structure factors, a feature that is absent in neutral polymers. We show that this additional peak describes the intra-molecular correlations between the charged side chains.

Highly oriented VO2 (M1) thin films are difficult to produce using non-crystalline substrates. For example, to produce such films on glass has required post-annealing or the use of a ZnO transparent layer. Here, we overcome this challenge and report highly oriented VO2 (M1) in the (100) plane directly on the glass substrate by pulsed laser deposition (PLD). We study the influence of the laser wavelengths (1064, 532, 355 and 266 nm) on the orientation of VO2 (M1) deposited on Corning glass. We find that the laser wavelength of 532 nm leads the most highly a-axis textured VO2 (M1) demonstrating the highest reversible metal-to-insulator at about 62 °C with a lowest hysteresis width of approximately 9 °C. One of the conditions is to select the green 532 nm wavelength laser in PLD as this particular laser wavelength also produces films with highest roughness value (of more than 60 nm) when compared to other wavelengths which produce films of roughness values less than 40 nm.

This research introduces an application of an electric impedance sensing technique to investigate cell attachment of normal epithelial cells (HaCAT) and cancerous cells (A431) before and after addition of Ganoderma Lucidum (reishi). In this study, an impedance sensing system is used to measure and characterize real-time changes in electric impedance (resistance and capacitance) with respect to an alternating current (AC) applied to HaCAT and A431 cell colonies. The impedance data is related to the properties of cell spreading, attachment, and delamination. The effect of reishi at dosages of 0.005, 0.01, and 0.02 mg/ml on these cellular properties was inferred from impedance data. The initial impedance data show that resistance is greater for A431 cells than HaCAT cells and that capacitance for A431 cells is less than the capacitance for HaCAT cells. Further, the data shows the resistance for HaCAT cells and for A431 cells increases with time, and the capacitance for both decreases with time. The impedance data analysis shows that reishi plays no role in altering the impedance of the cellular matrix. At most, reishi serves as a lubricant to allow partial detachment and reattachment of HaCAT cell-to-cell bonds, thus reordering (< entropy) the cellular matrix. This effect is not seen in A431 cell colonies.

A hollow γ-TNB turbine blade was 3D printed in this studying using the –R Optomec LENS machine from the elemental powders of aluminium, niobium and titanium making use of the laser “in situ” alloying approaching. The printed blade was characterised of a nearly lamellar β microstructure in the As-built state. The microstructure of the blade post heat treated was characterised of grain growth and coarsening and the formation of the γ phase which was of the result of the transformation of β. This transformation was also observed in the As-built state and is reported here for the first time. A massive crack that was observed half-way through in the built was attributed to the thermal shocks that are experienced by the almost immediately after manufacturing. The EDS and Map taken on the As-built and heat treated samples conclude that there was no segregation in the alloying element during manufacturing and that the blade was of the dual phase. Hardness results indicated the heat treated sample was 91 HV0.5 lower in hardness when compared to the As-built component. The successful print of this hollow blade indicate that γ-TNB and other Ti-Al alloys can be printed with the LENS but if a crack free sample was to be achieved the set-up had to be manipulated or addition resources must be added to adapt the set-up. Meanwhile the successes of this study show that LENS is going to be considered as a cost-effective manufacturing tool in the future for 3D printing Ti-Al and other metallic structure that would have improved properties when compared to traditional manufacturing technique such as casting and the powder bed systems.

Ion beam analyses were completed on single crystal LiD (lithium hydride with deuterium on the hydrogen sites) to determine products of hydrolysis with decarbonated H2O (with protium-hydrogen) in an inert gas. Rutherford backscattering spectrometry showed movement of oxygen into the bulk of LiD samples. Hydrolysis rates for the single crystal LiD showed relatively slow initial growth of an oxygen-containing layer. Final growth rates varied widely with H2O level, from 1010 to 1015 (atoms/cm2)/min. at 5.6 and 28 mmol/min. H2O respectively. Simulations of spectra show the hydrolysis product to be LiOH. Elastic recoil detection identifies the hydrogen in the hydroxide layer upon dosing with H2O (with natural, protiated hydrogen) as primarily protium. Micrographs showed island growth occurring initially, with convergence to a full-coverage hydrolysis layer.

Drug contamination in water is one of the current fields of study. Since 1990, the presence of drugs in drinking water has been a concern to scientists and public. In Mexico, these organic compounds are not efficiently removed in wastewater treatment plants; therefore, alternative methodologies have been studied that allow these compounds to have a high percentage of degradation or be completely degraded. One example of these techniques is heterogeneous photocatalysis which has obtained positive results in the degradation of drugs using ZnO nanoparticles. These are commonly selected for their electrical characteristics, even though they disperse in water and an additional unit operation is required to separate them from the liquid medium. To eliminate drugs with nano particles in a single stage, polycaprolactone-based membranes with adhered ZnO nanoparticles, by means of electrospinning, were prepared to degrade drugs such as diclofenac. The technique used has shown to efficiently break down diclofenac in 4 hours according to the capillary electrophoresis readings.

This paper reports a way to obtain BaPbO3-x and BaPb1/3Bi2/3O3-x perovskite-type compounds. The method is based on the initial preparation of Ba(COO)2⋅0.5H2O and Pb(COO)2⋅oxalates, and the subsequent calcination of the equimolar physical mixture of these oxalates until the desired compounds BaPbO3-x and BaPb1/3Bi2/3O3-x are formed. To obtain BaPb1/3Bi2/3O3-x, the oxide Bi2O3 is added to the mixture of oxalates and calcined together with them. The temperature for the formation of BaPbO3-x and BaPb1/3Bi2/3O3-x was estimated to be 850°C. These final compounds prepared by calcination were composed of a single phase and exhibited monoclinic crystal structure. The thermal decomposition of the Pb(COO)2 oxalate and the formation of BaPbO3-x and BaPb1/3Bi2/3O3-x were investigated by X-ray powder diffraction (XRPD) and differential thermal analysis (DTA).

Morpho-Butterfly inspired lamella structures were fabricated to make a multivariable optical sensor for measuring percent level concentrations of H2 and CO in a high temperature, zero-O2 environment. The SiO2 and Si3N4 3D structures were covered with gold nanoparticles (AuNPs) and cerium IV dioxide (CeO2) and exposed to varying concentrations of H2 and CO at 300°C. Experiments with AuNP sizes with an average diameter of 11 ± 3 nm and 3 ± 0.5 nm (larger and small AuNPs, respectively) showed that the larger AuNPs had a stronger response to the same concentrations of H2 and CO with less CO saturation and baseline drift. Further testing in the presence of 1% hydrocarbons (HCs) as an interfering gas showed excellent response to up to 17% H2 and CO in a zero-O2 environment with changes in reflected intensity of -13.1 ± 0.4% for H2 and -5.8 ± 0.3% for CO. The presence of HCs did not induce any baseline drift, with the total amount of drift being less than 0.5% over 13 hours of testing at 300°C.

Polymeric conjugated materials are very promising for developing future soft material-based semiconductors, conductors, electronic and optoelectronic devices due to their inherent advantages such as lightweight, flexible shape, low-cost, ease of processability, ease of scalability, etc. There are a number of ways to tune material properties via post-processing treatments such as annealing, solvent additives, or doping. One challenge of solution processed organic thin film electronics is the repeatable and well-defined morphological control of the resulting films after deposition. In this study, we observed how the addition of diiodo-alkanes to poly-3-hexyl-thiophene (P3HT) solutions effect the formation of resulting thin films. These additives have various boiling points that will affect the drying properties of cast thin films. We also sought to observe if any halogen bonding interaction between iodine and sulfur occurs and if this interaction can be used to promote polymer morphological self-assembly. Techniques such as UV/Vis spectroscopy, X-ray diffraction, and Atomic Force Microscopy were used to probe the evolution of the film morphology as the additives were added to the solutions. 1,8-diiodooctane doped films showed the best overall device performance. This could be due to its favorable interaction with the side chain of P3HT as seen in it morphological properties. This study may result in a new technique that can be used to enhance the solid-state morphology of thin films for high performance electronic applications.

Pneumonia has contributed greatly to child mortality, especially among children under the ages of five in sub-Saharan Africa, killing more children than the number of children dying from HIV/AIDS. The current methods of diagnosing pneumonia involved physical examination and chest x-ray which are limited by low accuracy, high error margins, higher cost, and stands the risks of inducing cancer. In this work, a low-cost, non-invasive biomedical device was designed and developed to improve accuracy in diagnosing pneumonia. The device functions to detect fluid in a lung consolidated by pneumonia. Dry grouting sponge was used as a phantom for a healthy lung, while a wet sponge was used to mimic a pneumonia-consolidated lung. Surface exciter was used to produce sound waves which travelled through one side of the phantom and are detected on the other end using an electronic stethoscope. The signals detected were digitally analyzed using MATLAB and AUDACITY software. The differences in resonant frequencies from the power spectrum analysis of sound waves as they travelled through the sponges were used to distinguish between a pneumonia-consolidated lung and a healthy lung.

YBO3:Eu3+ crystals with flower-like hierarchitecture are readily synthesized through a folic acid assisted hydrothermal process using polyborate precursors in the aqueous solution. It was found that the pH value , borate/yittrium ratio and the mass of folic acid take effects on the morphology and photoluminescence emission intensity of YBO3:Eu3+ crystals. The product with the small flower-like hierarchitecture was obtained under the conditions of pH value at 9, borate/yittrium ratio at 2 and the mass of folic acid at 0.44 g, showing the strongest photoluminescence intensity. The growth process of the YBO3:Eu3+ flowers and microflowers was invesitgated based on the time-dependent experiments, which showed that the growth mechanism of the flower-like hierarchitecture follows an in situ growth rather than self-assembly process as reported previously. Such a hydrothermal route using folic acid as a capping agent may provide a green and effective method for fabricating useful and complex 3D architectures of LEDs phosphors.

Data science has advanced significantly in recent years and allows scientists to harness large-scale data analysis techniques using open source coding frameworks. Data science is a tool that should be taught to science and engineering students in addition to their chosen domain knowledge. An applied data science minor allows students to understand data and data handling as well as statistics and model development. This move will improve reproducibility and openness of research as well as allow for greater interdisciplinarity and more analyses focusing on critical scientific challenges.

In-solution ligand exchange of PbSe QDs is used to examine the effect of capping ligand on the carrier density of PbSe QD films. Results show that carrier density can be modulated by a factor of 5 by choice of ligand without any additional post deposition treatments. Proper fabrication and measurement conditions for calculating carrier densities from C-V measurements using a sandwich structure on P-doped Si/SiO2/Al2O3/QD/Au structure capacitance devices are outlined. Combining carrier density results with field-effect-transistor measurements, promising ligands which display lower carrier densities without having a significant drop off in carrier mobility are identified as candidates for photodetection purposes.

X-ray imaging is a valuable technique used for medical imaging and non-destructive inspection of industrial products. However, the radiation may put humans at risk of developing cancer. Consequently, highly sensitive X-ray detectors, which enable X-ray imaging at a low dose rate, are required. Metal halide perovskite materials have demonstrated excellent X-ray detection performance including a high sensitivity owing to their high absorption coefficient, high carrier mobility, and long carrier lifetime. However, perovskite thick films with a large area, which is essential to realize the application of such materials to X-ray imaging devices have not been extensively investigated. To this end, in this study, a polymer is employed as a buffer layer to avoid film exfoliation, which makes it difficult to fabricate perovskite thick films, and a 110-μm-thick CsPbBr3 film is successfully obtained using a scalable solution method. In addition, an X-ray detector based on the CsPbBr3 thick film is fabricated, which demonstrates a sensitivity of 11,840 μC Gyair–1 cm–2. This sensitivity is approximately 600 times higher than that of the existing commercial a-Se X-ray detectors.

Most optoelectronic characteristics of two-dimensional (2D) materials are associated with excitonic effects. Excitonic effects in 2D material have been intensively investigated, and various efforts to engineer exciton behavior in 2D materials have been reported for advanced nanophotonic and optoelectronic applications. Excitons in 2D semiconductors can be controlled by external stimuli, including mechanical, electrical, thermal, and magnetic stimuli. Mechanical stimuli applied to a 2D material can generate uniform or non-uniform deformation and strain gradient in the 2D lattice, which creates a strain-induced bandgap energy gradient in the 2D material. In an inhomogeneous bandgap energy gradient generated by a non-uniform strain gradient, excitons drift across the energy gradient. Exciton engineering in deformed 2D materials aims to control exciton movement by mechanical strain. In this snapshot review, we focus on exciton engineering in a mechanically deformed 2D material and their potential towards advanced optoelectronic and photonic applications.

C-reactive protein (CRP) and cardiac troponin I (cTnI) biomolecules represent the earliest enzymes that appear in the blood when a cardiac injury occurs. Real-time and selective detection of these biomarkers is essential for the prediction and detection of cardiovascular diseases at an early stage. Here we report on the label-free specific detection of both proteins at picomolar concentrations using fabricated nanowire-based biosensors. We demonstrate a novel functionalization technique based on the attachment of dibenzocyclooctyne (DBCO)-linked troponin-specific aptamers to azide-functionalized silicon (Si) nanowire (NW) surface. Due to the fast and reliable immobilization of cTnI-specific aptamers and CRP-specific antibodies on the Si NWs, the fabricated devices can rapidly detect target biomolecules demonstrating high sensitivity. We confirm the attachment of proteins to the surface of Si NWs by atomic force microscopy (AFM). Moreover, we demonstrate that nanowire structures of different sizes enable the detection of biomarkers in a wide concentration range (from 1 pg/ml to 1 µg/ml), corresponding to CRP and cTnI elevation levels during the early stage of disease formation.

The Battelle Critical Care Decontamination System™ (CCDS™) decontaminates N95 filtering facepiece respirators (FFRs) using vapor phase hydrogen peroxide (VPHP) for reuse when there is a critical supply shortage. The Battelle CCDS received an Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) in March 2020. This research focused on evaluating the mechanical properties of the straps as an indicator of respirator fit. The objective was to characterize the load generated by the straps following up to 20 don/doff and decontamination cycles in Battelle's CCDS. In general, the measured loads at 50 and 100% strains after 20 cycles were similar (±15%) to the as-received controls. Qualitatively, reductions in the load may be associated with loss of elasticity in the straps, potentially reducing the ability to obtain a proper fit. However, small changes in strap elasticity may not affect the ability to obtain a proper fit given the potential for variation in strap length and positioning on the head. Regardless, prior to reusing a N95 respirator, it is important to complete a visual inspection to ensure it is not damaged, malformed, or soiled. If so, it is recommended to discard the respirator and use a different one. Similarly, the respirator should be discarded if the wearer cannot obtain a proper fit during the user seal check.