Rubberlike insect cuticle is a light fibrous composite, which exhibits great deformability and long-range elasticity due to the presence of a large amount of the elastomeric protein resilin. The presence of resilin in specific locations in the insect body leads to the assumption that its main function is loss-free storage of energy. Rubberlike cuticle was identified, for the first time, in the femur base of the sand field cricket, Gryllus firmus, using fluorescence microscopy and various staining methods. Dynamic nanoindentation testing was then used to investigate the differences in the mechanical properties of rubberlike cuticle between males and females and wing morphs of this species. Significant changes in storage, loss moduli, and resilience were captured between female wing morphs. The results provide insight into the structure–function relations associated with the properties of insect joints from different morphs and genders.

A physical model is developed for the enhancement of the Seebeck coefficient (S) in a porous thermoelectric material with inhomogeneous porosity. The pores are assumed to be hole and of spherical shape. We take into account the presence of trap centers situated at pore/medium interfaces and neglect changes in the carrier effective mass due to the band-bend. We show that the porosity always leads to an increase in the absolute value of S. A simple relation is derived for S in nondegenerate n-type semiconducting materials in the case when the main contribution in the carrier relaxation time at zero porosity is from the scattering on acoustic phonons. We have shown that the value of S does not depend on the orientation of the porosity gradient with respect to the direction of the temperature gradient. The relative growth of the Seebeck coefficient compared to its value in the bulk material of the same volume is examinated for different number of the pore groups with different characteristic sizes at various pore size distributions.

A novel and simple method for gelcasting of alumina was developed using a nontoxic and water-soluble copolymer of isobutylene and maleic anhydride (commercially called Isobam). In this method, there is requirement of only a small amount of Isobam (0.3 wt%) and neither initiators nor dispersants are needed for preparation and gelation of a 50 vol% solids loaded alumina slurry. The gelation rate increased with increasing solids loading but decreased with increasing Isobam content. A typical gelation time was 38 min for the slurry containing 50 vol% solids loading and 0.3 wt% Isobam. The resultant wet gel was strong enough to allow reversible bending and twisting. This simple gelling system is attractive for wet forming of ceramics because only a single additive, which acts as both dispersant and gelling agent at room temperature in air, is used.

Silicon carbide (SiC) detectors were used to analyze the multi-MeV ions of the plasma produced by irradiation of various targets with a 300-ps laser at intensity of 1016 W/cm2. The SiC detectors were realized by fabricating Schottky diodes on 80 μm epitaxial layer. The low dopant concentration and defect density of the epilayer allowed the realization of good performance detectors. The use of SiC detectors ensures the cutting of the visible and soft ultraviolet radiation emitted from plasma enhancing the sensitivity to very fast ions. The time-of-flight spectra obtained by irradiating different targets show a peak associated to protons and various peaks relative to different charge states of ions. Processing of the experimental data allows to estimate the energies of the protons and of the different ions emitted from laser-induced plasma. The SiC detector results are compared with the ones obtained by Ion Collector and a Thomson Parabola spectrometer.

A rapid low-pressure plasma sintering process of inkjet-printed silver nanoparticles is reported, yielding a conductivity of 11.4% of bulk silver within 1 min of plasma exposure and a final conductivity up to 40% of bulk silver for longer sintering times. The maximum processing temperature did not exceed 70 °C, which enabled the use of cost-effective polyethylene terephthalate (PET) foils. Fully functional radio-frequency identification (RFID) tags were prepared with inkjet-printed antennas, which showed similar results as screen-printed devices. The inkjet-printed antennas require significantly less materials, hence thinner layers, than the screen-printed references.

Sputter-deposited epitaxial (111) and (110) Ag films have high-density nanotwins with respective twin boundary orientations perpendicular and angled to the growth direction. Twin density in as-deposited (111) Ag films is much greater than in (110) films, leading to higher hardness in the (111) films. Annealing up to 800 °C (homologous temperature of 0.85 Tm) leads to increased twin thickness, although the average twin thickness remains <100 nm in both systems. Twinned volume fraction falls dramatically in annealed (110) films but remains constant at ∼50% in (111) films. The mechanisms leading to the elimination of nanotwins in (110) films and their remarkable stability in (111) films at elevated temperatures are discussed. Coarsening and elimination of twins result in hardness reduction after annealing. The variety of microstructures achieved via annealing allows for the introduction of a strengthening model considering both twin and grain boundaries.

This study investigated the microstructure and machining characteristics of a Zr38.5Ti16.5Cu15.25Ni9.75Be20 bulk metallic glass (Zr-BMG) alloy machined using electro-discharge machining (EDM). After EDM, the hardening effect near the outer surface of the electro-discharge machined (EDMed) Zr-BMG alloy originated from the surface carbides of the recast layer, ZrC and TiC. The thickness of the recast layer, crater size, and the surface roughness increased with greater pulse energy. Furthermore, the EDM can generate a porous recast layer and convert the Zr-BMG alloy surface into a carbide surface, which is a potential method to fabricate biomaterials. Experimental results also show that the material removal rate of this alloy in the EDM process was significantly related to the pulse current IP and pulse duration τP. Many electro-discharge craters and recast materials were observed on the surface of the EDMed Zr-BMG alloy. The surface roughness of the EDMed Zr-BMG alloy was found to obey the empirical equation of Ra = β(IP × τP)α.

The relationship between electric current direction and recrystallization rate as well as the resulting texture induced by electric current pulses (ECPs) was investigated in a Cu–Zn alloy. To distinguish the effect of electric current direction on recrystallization rate, the same input energy was exerted upon the samples to eliminate the effect of Joule heating induced by ECPs. Results showed that the recrystallization-related nucleation rate could be greatly enhanced when the electric current was dispositioned at an angle to the rolling direction. The main mechanism for the different nucleation rates might be ascribed to the different driving forces for recrystallization induced by ECPs when there was an angle between the electric current direction and the rolling direction.By all reckoning, it was expected that the ECP treatment would provide a promising approach for controlling the nucleation rate by changing the exerted electric current direction.

The present work demonstrates the synthesis of Cu–10 wt% TiB2 composites with a theoretical density of more than 90% by tailoring the spark plasma sintering (SPS) conditions in the temperature range of 400–700 °C. Interestingly, 10 wt% Pb addition to Cu–10 wt% TiB2 lowers the sinter density and the difference in the densification behavior of the investigated compositions was discussed in reference to the current profile recorded during a SPS cycle. The sintering kinetics and phase assemblage were also discussed in reference to surface melting of the constituents prior to bulk melting temperature, temperature dependent wettability of Pb on Cu, diffusion kinetics of Cu as well as the formation of various oxides. An important result is that a high hardness of around 2 GPa and relative density close to 92% ρtheoretical was achieved for the Cu–10 wt% TiB2–10 wt% Pb composite, and such a combination has never been achieved before using any conventional processing route.

The conventional process for preparing dry spinnable regenerated silk fibroin (RSF) aqueous solution needs not only an addition of Ca2+ but also an adjustment of pH value. In this work, an RSF dry spinning dope was prepared by using a simplified method with solely adding Ca2+. Compared with the conventional RSF solution, the simply prepared aqueous solution showed similar content of β-sheet conformation and diameter of RSF aggregates but lower viscosity. Furthermore, the posttreated RSF fiber dry-spun from this simply prepared solution showed higher crystallinity and crystalline orientation, smaller crystallite size, and better mechanical properties. It could be concluded that Ca2+ played a much more important role than pH value in improving the structures and properties of RSF spinning solution and fibers. Therefore, the step of adjusting pH value could be excluded in the process of preparing high performance RSF fibers.

Isothermal crystallization kinetics of gamma-irradiated syndiotactic polystyrene (sPS) has been investigated by differential scanning calorimetry. Amorphous sPS samples were irradiated in air with gamma ray at various doses from 0 to 800 kGy, at a rate of 30 kGy/h, and melt-crystallized at different temperatures and times. Kinetics parameters were determined using Avrami's model with Gaussian functions and a modified Arrhenius equation. Isothermally crystallized sPS irradiated in air with gamma ray exhibited multiple endothermic melting peaks corresponding to various crystalline forms, and the radiation dose had a strong effect on their melting enthalpies, crystallinities, and crystallization kinetic parameters. The amount of the α-crystalline form increased with increasing crystallization time and those of the β- and β′ forms had an opposite trend. Both crystallization half time and crystallization activation energy of the α form in gamma-irradiated sPS increased with increasing radiation dose.