Cordierite (Mg2Al4Si5O18), Mullite (Al4+2xSi2-2xO10-x) and Cordierite-Mullite ceramic materials were obtained from a stoichiometric mixture of coal fly ash (CFA) as a source of SiO2 and Al2O3, plus high-purity MgO and Al2O3. The starting stoichiometric mixtures were homogenized, and then uniaxially pressed, cold isostatically pressed, and sintered at 1200-1600 °C for 2-5 h. The sintered materials were characterized by X-ray diffraction, scanning electron microscopy, Vickers microhardness, density and four-point flexural strength. In general, the desired phases tended to form in the composites at temperatures of 1350 or 1400 °C, with a considerable amount of glassy phase developing from 3 h onwards at one of those two temperatures, depending on the composite composition. The microstructure of the composites consisted of a matrix of Cordierite and interwoven needles of Mullite. The bulk density decreased, while the flexural strength and the Vickers microhardness increased with increasing nominal content of Mullite in the composites. A synergistic effect taking place between Cordierite and Mullite enhances the mechanical properties of the composites.

One of the most important non-destructive methods for on-site analysis of bronze artifacts is portable X-ray fluorescence (XRF). However, bronze artifacts are usually heterogeneous in composition due to, among other things, the segregation of lead, which is hard to be eliminated through annealing treatments. In the present work, Cu-Sn-Pb alloys with homogenous composition and microstructure is fabricated by powder metallurgy technique. The suitability of the standard curve using Cu-Sn-Pb alloys by powder metallurgy as the standard samples for XRF on the analysis of bronze artifacts is evaluated. It is shown that this proposed method can be transferred to portable XRF to acquire accurate on-site composition information of bronze artifacts.

While the most promising longitudinal recording systems cannot surpass the theoretical limit of about 200 Gb/in2 for areal recording density and the demand for higher densities is permanently increasing, the perpendicular magnetic recording constitutes the realistic issue to the longitudinal one. The perpendicular magnetic recording offers significant advantages, the most important being stronger write and read fields, and therefore the use of media of higher anisotropy, smaller grain size, higher signal-to-noise ratio, and a better thermal stability. Unfortunately, the perpendicular recording has to cope some important physical and technological difficulties. To overcome them, many ingenious solutions were proposed. In this paper the coupled granular/continuous (CGC) media, a subtle association of the continuous and, respectively, granular media, are analysed from the viewpoint of their magnetic and recording properties. The challenges and possible improvements of CGC media are discussed.

Dense, controlled-impedance, superconducting cables with small cross-sections are desirable, especially for quantum computing applications. In this study, superconductivity properties, rf microwave response and mechanical reliability performance of embedded Nb dc cables and Nb microstrip transmission line resonators with different thicknesses of polyimide PI-2611 encapsulation layers (0, 4 and 8 μm) have been investigated. Critical temperature (Tc) and critical current (Ic) of embedded Nb dc cables are ∼ 8.2 K and ∼ 0.2 A, respectively. Embedded Nb resonators yield high loaded quality factor (QL), with values as high as 14481 at ∼ 1.2 K and at a fundamental resonance of ∼ 2 GHz. From mechanical fatigue testing, we have observed that a polyimide encapsulation layer can effectively enhance the mechanical reliability of superconducting Nb flexible cables.

We show that by subsequent sensitization of nanostructured ZnO photoanodes with N-719 and Rose Bengal dyes an improvement or worsening of the cell efficiency may be obtained, relating to photoanodes sensitized with N-719 dye only (J SC = 2.97 mA/cm2, V OC = 0.68 V, η = 0.99%) depending on the order in which the dyes are applied. We observe that for the case when the N-719 dye is followed by Rose Bengal an increase in efficiency, short circuit current and open circuit voltage is observed (J SC = 3.95 mA/cm2, V OC = 0.71 V, η = 1.26%), which we relate to the cascade band alignment of the ZnO and the dyes. In the case when Rose Bengal is first on ZnO followed by N-719, a lowering of all parameters is observed (J SC = 2.86 mA/cm2, V OC = 0.64 V, η = 0.94%) due to the trap band alignment. Electrochemical impedance spectroscopy measurements and modelling confirmed this theory showing longer electron lifetimes in the photoanode for the cascade band alignment, enhancing electron-hole separation, than for the trap alignment, facilitating electron-hole recombination.

In the case of General Chemistry, many engineering students only take a one semester class with important topics such as kinetics and equilibrium being given limited coverage. Considerable time is spent covering materials already covered in other courses such as General Physics and Introduction to Engineering. Moreover, most GChem courses are oriented toward health science majors and lack a materials focus relevant to engineering. Taking an atoms first approach, we developed and now run a one-semester course in general chemistry for engineers emphasizing relevant materials topics. Laboratory exercises integrate practical examples of materials science enriching the course for engineering students. First-semester calculus and a calculus-based introduction to engineering course are prerequisites, which enables teaching almost all the topics from a traditional two semester GChem course in this new course with advance topics as well. To support this course, an open access textbook in LibreText, formerly ChemWiki was developed entitled General Chemistry for Engineering. Many of the topics were supported using Chemical Excelets and Materials Science Excelets, which are interactive Excel/Calc spreadsheets. The laboratory includes data analysis and interpretation, calibration, error analysis, reactions, kinetics, electrochemistry, and spectrophotometry. To acquaint the students with online collaboration typical of today’s technical workplace Google Drive was used for data analysis and report preparation in the laboratory.

In the present work, NaI – LiBH4 system fabricated by ball milling were post annealed and their variation of Li+ ion conductivity were investigated. From the change of lattice parameters by post annealing, it was suggested that unreacted LiBH4 existed in as-milled sample further dissolved into NaI, which implied an enhancement of the sample homogeneity. On the other hand, the segregation of LiI was anticipated when ball milled 15NaI·LiI (BH4 free sample) was annealed at 423 K. Li+ conductivity was decreased by post anneal process and compositional dependence of an activation energy for Li+ conduction was indicated for the homogeneous NaI – LiBH4 system.

Nano-thin films of Lu2O3 with 80nm thickness have been deposited on metal-coated glass substrate in metal-insulator-metal (MIM) geometry by electron-beam evaporation technique. High field and temperature dependent electrical characterization on grown MIM structures have been investigated in symmetric electrode configuration using Al, Cr or Cu metals. The temperature dependent I-T characteristic features have been found to support the conduction mechanism across MIM systems to be an electrode-limited process except for Al-Lu2O3-Al device, which show Poole-Frenkel mechanism in high electric field region. The associated parameters such as activation energy (∆E), coefficient of barrier lowering (β) and effective height of Schottky barrier at zero biasing (Фo) have been evaluated at different values of temperature and electric field to further investigate the dominent conduction mechanism.

According to the Centers for Disease Control (CDC) and prevention, at least 2 million people in the United States become infected with antibiotic-resistant bacteria, and at least 23,000 people die each year as a direct result of those infections. One alternative to traditional antibiotics is bacteriophage (phage) therapy. Phage therapy utilizes bacteria-specific viruses to infect and kill bacteria cells. The specificity of these viruses is beneficial in that phage used for therapeutic purposes do not harm the human microbiota, nor do phage infect eukaryotic cells. It has been discovered that iron-doped apatite nanoparticles (IDANPs) significantly enhance phage killing of bacteria cells. The biocompatibility of apatite, coupled with its effectiveness as an adjuvant to enhance an alternative antibiotic therapy, makes it of interest for medical applications. Previously, researchers have encased phage in a microfluidic channel in coaxially electrospun fibers, allowing phage to remain viable after several weeks storage at 4 °C. Here, we have constructed a polymer fiber layer using electrospinning (ES) for delivery of IDANP adjuvants to compliment phage treatment delivery fibers. The IDANP delivery layer constructed is composed of polyethylene oxide (PEO) doped with the nanoparticles. When compared to media-only and IDANP-only controls, results show IDANPs delivered through a PEO fiber mesh remain effective at enhancement of phage infectivity.

Mono-crystalline elastic constants of equiatomic quinary Cr-Mn-Fe-Co-Ni high entropy alloy with the fcc structure have experimentally been determined by a resonance ultrasound spectroscopy at room temperature. The values of the bulk modulus of the high entropy alloy experimentally determined are similar to other conventional fcc metals when the values are normalized by the melting points. This indicates that the entropy change at melting is similar to that of conventional metals. The values of Pough’s index and the Cauchy pressure are determined as 1.79 and -11.6 GPa, respectively. When the ductility of the alloy is judged from the indices, the ductility of the high entropy alloy is limited. In order to explain the negative Cauchy pressure of the high entropy alloy, it is required to assume that relatively strong directional interatomic bondings like intermetallic compounds exist in the alloy though the crystal is disordered solid solution.

Diatoms represent a natural source of mesoporous silica whose applications range from biomedical to photonic fields. Porous hierarchically organized micro structures, the biosilica shells called frustules, can be obtained by removal of the organic biological matter from the unicellular living algae. Diatoms frustules have been investigated as scaffold for bone tissue growth taking advantage of their nanostructured surface and of the possibility to chemically modify the biosilica. Here we report on an easy way to calcium-doped biosilica supports for bone tissue regeneration by in vivo feeding the algae. FTIR and EDX analyses confirmed the incorporation of calcium into the mesopouros biosilica. Cell viability studies showed an ameliorative effect on the Saos-2 cells spreading compared with the cells grown on non-doped biosilica supports.

Due to their highly favorable materials properties such as direct bandgap, appropriate bandgap energy against solar spectrum, and ability to form multiple junctions, epitaxially grown III-V compound semiconductors such as gallium arsenide have provided unmatched performance over silicon in solar energy harvesting. However, their large-scale deployment in terrestrial photovoltaics remains as a daunting challenge mainly due to the high cost of growing device-quality epitaxial materials. In this regard, releasable multilayer epitaxial growth in conjunction with printing-based deterministic materials assemblies represents a promising approach that can overcome this challenge but also create novel engineering designs and device functionalities, each with significant practical values in photovoltaic technologies. This article will provide an overview of recent advances in materials design, fabrication concept, and nanophotonic light management of multilayer-grown nanomembrane-based GaAs solar cells aiming for high performance, cost-efficient platforms of III-V photovoltaics.

The electrical characteristics of Au/Ni/Ti/ n-SiC contacts have been examined as a function of implant dose (1013-1014 ions/cm2) at 5 KeV and temperature of annealing (750-1000 °C). Measurements of specific contact resistance, ρc, were approximately constant at lower implant doses until increasing at 1 x 1015 ions/cm2 for both C and P ions. Annealing at a temperature of 1000 °C has reduced the value of ρc by an order of magnitude to ∼1 x 10-6 Ω.cm2 at implant doses of 1013-1014 ions/cm2. Auger Electron Spectroscopy (AES) has shown that annealing at 1000 °C resulted in a strong indiffusion of the metallization layers at the interface.

Plutonium oxide (PuO2) is one of the most highly radioactive components of nuclear fuel waste streams and its storage poses particular challenges due to the high temperatures produced by its decay and the production of gases (particularly H2 and steam). Its high radiotoxicity necessitates the use of analogues, such as CeO2, to allow the comprehensive study of its interaction with water under storage conditions.

We have developed a method which enables direct gravimetric measurement of water adsorption onto CeO2 thin films with masses in the microgram region. Porous CeO2 films were fabricated from a surfactant based precursor solution. The absorption of water onto the CeO2 coating at different relative humidities was studied in a closed reactor. Quartz Crystal Microbalance (QCM) gravimetry was used as a signal transducer, as changes in crystal resonant frequency due to absorbed mass are directly and linearly related to mass changes occurring at the crystal surface. Using this method, we have determined the enthalpy of absorption of water onto CeO2 to be 49.7 kJmol–1 at 75°C, 11 kJmol-1 greater than the enthalpy of evaporation. This enthalpy is within the range predicted for the absorption of water onto PuO2, indicating this method allows for investigation of water absorption using microgram samples.

Stability of functional devices such as light-emitting devices and chemical or biological sensors is an important issue nowadays. Nanostructured silicon made using top-down methodologies is being employed as a material to develop such systems, but surface stability to external ambient conditions is still an open question. One of those important conditions is oxidation. Although there exist models accounting for the role of oxide layers on semiconductor systems, experimental data is still required to provide further useful information. In this paper, we perform oxidation processes to light-emitting nanostructured silicon and study the contribution of quantum dots and quantum wires to photoluminescence as surface oxidation evolves. Cross-correlations with infrared spectroscopy are also included.

In this work, we propose a multi-sensor platform where sensors are stacked over one another (3D stacked) each offering a unique functionality. The technique involves the use of Polyurethane (PU) sponge and PVDF/graphene (Gr) /ZnO composites for various sensing applications. The sponge was made conductive by dipping it in different weight percentages of pencil lead dispersed in ethanol through ultrasonication. Large area Gr/PVDF films were fabricated by simple solution mixing and casting method which also served as a substrate for the 3D stacked sensor. ZnO was grown hydrothermally over Gr/PVDF film by masking a portion of Gr/PVDF film to form a p-n junction. Silver paste and copper tape were used as contact pads. All the three fabricated devices were stacked with PU sponge sandwiched between Gr/PVDF/ZnO (top) and large area Gr/PVDF (bottom) as substrate. Performance of individual sensors and 3D stacked sensor was compared and no notable change was observed. The 3D stacked sensor array platform with its multifunctionality would be a step ahead in wearable electronics which can be integrated on human and can function as an e-skin for burn and acid victims, robotics and human-machine interactions.

We demonstrate high vertical yield InAs1-xSbx (0 < x ≤ 0.18) nanowire arrays grown on InP (111)B substrates by calalyst-free selective-area metal-organic chemical vapor deposition. High antimony composition is achieved by pulsing the arsenic flow to reduce the effective arsenic partial pressure while keeping the antimony partial pressure fixed. This increases the antimony vapor phase composition while allowing the antimony partial pressure to be kept low enough to avoid antimony condensation on the growth mask. InAsSb nanowire arrays show strong emission by photoluminescence at 77 K, covering a wavelength range of 3.77 – 5.08 μm. These results pave the way to engineering optical properties and enabling hybrid integration for nanoscale mid-wavelength infrared optical devices.

The nanoscale miniaturization of hybrid organic-inorganic perovskite has given rise to new functionalities, but the full understanding of the multifaceted properties of perovskite nanostructures is still incomplete. Using a combination of optical and magnetic resonance (EPR) spectroscopies, we focused our investigation on the photoinduced electron transfer process taking place in perovskite nanocrystals blended with the fullerene derivative PCBM. In particular we analyzed the different effect of two types of nanocrystal ligands, namely octylamine and oleylamine, on the photoinduced processes. The electron transfer process resulted in efficient fluorescence quenching in a mixed solution and in the formation of charges (PCBM anions) detected by EPR in the blends. Both the optical and EPR techniques revealed a stronger effect when the shorter ligand is present. Finally, pulsed EPR demonstrated the stabilization of the photogenerated charges in proximity of perovskite nanocrystals.

Twinning induced plasticity (TWIP) steels are one of the most attractive advanced high-strength steels for structural applications due to their unique combination of strength and ductility, which is associated with so-called “mechanical twinning”, where twins act as strong obstacles to the dislocation motion. In this context, Nb addition to TWIP steel increases the strength and refines grain size by nanoscale NbC precipitates. Nowadays, high-manganese TWIP steels are extensively studied. However, information in the specialized literature about their tribological properties is limited. This research work studies the wear behavior of high-manganese austenitic Fe–20Mn–1.5Si–1.5Al–0.4C TWIP steel microalloyed with Nb. The wear behavior was evaluated under non-lubricated sliding condition using the “pin-on-ring” technique. As-solution heat treated samples were worn under loads of 53, 104 and 154 N, and at sliding speeds of 0.22, 0.60 and 0.87 m/s. The wear resistance was evaluated in terms of the loss weight. Wear debris and worn surfaces were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). In general, results show that the wear resistance significantly improves as the sliding speed increases. On the other hand, Nb addition to present TWIP steel produces a slight increase of the wear resistance. Also, it was found that the oxide layer plays a significant role in the wear resistance behavior of this kind of steel.

Advanced reduced activation ferritic/martensitic steels and oxide dispersion-strengthened steels exhibit significant radiation embrittlement under low temperature neutron irradiation. In this study we focused on atom probe tomography (APT) of Eurofer97 and ODS Eurofer steels irradiated with neutrons and heavy ions at low temperatures. Previous TEM studies revealed dislocation loops in the neutron-irradiated f\m steels. At the same time, our APT showed early stages of solid solution decomposition. High density (1024 m–3) of ∼3–5 nm clusters enriched in chromium, manganese, and silicon atoms were found in Eurofer 97 irradiated in BOR-60 reactor to 32 dpa at 332°C. In this steel irradiated with Fe ions up to the dose of 24 dpa, pair correlation functions calculated using APT data showed the presence of Cr-enriched pre-phases.

APT study of ODS Eurofer found a significant change in the nanocluster composition after neutron irradiation to 32 dpa at 330 °C and an increase in cluster number density. APT of ODS steels irradiated with Fe ions at low temperatures revealed similar changes in nanoclusters.

These results suggest that irradiation-induced nucleation and evolution of very small precipitates may be the origin of low temperature radiation embrittlement of f\m steels.