Combination of superconducting (SC) and ferromagnetic (FM) sheets into layered SC/FM composites allows to obtain metamaterials with unusual magnetic properties: the effective magnetic permeability along the sheets could be much higher than in the perpendicular direction. One can design the magnetic cloak consisting of a shell from SC/FM composite protecting its inner space against the penetration of a static magnetic field. Difference between such a device and a usual SC or FM shield will be in its un-detectability by magnetic sensors checking the field distribution outside the cloak. Thus it could be considered a magnetic invisibility cloak and one can think about using it e.g. for protecting a sensitive electronic circuitry in an electric machine.

We have prepared a series of SC/FM cloaks using commercial coated conductors as the superconducting elements and various kinds of ferromagnetic sheets as the ferromagnetic elements. Finite element calculation was utilized to optimize the architecture. Experimental testing of the cloaking ability in static magnetic field was performed by scanning the field distribution in vicinity of the cloak. Detectability in low frequency (< 100 Hz) AC magnetic fields was tested in an AC magnetization set-up allowing to see both screening and dissipation signals. Recording of magnetization loops allowed to analyze in detail the dynamics of field interaction with the cloak. Reduction of the detected magnetic signature due to the cloak was confirmed, however it is still not complete. Tests of various arrangements of superconducting and ferromagnetic materials allowed to identify the main problems hindering to achieve a perfect cloaking.

Most of what is known about the Iron Age in Southeastern Kazakhstan has been learned from kurgan burials and historical accounts describing the largely nomadic lifestyle of steppe populations from the 8th century B.C.E. to the 5th century C.E. Recent archaeological surveys however, are revealing an unexpectedly large number of settlements at the edges of the steppe, along the northern slopes of the Tien Shan Mountains. One of these sites, Tuzusai, has provided a wealth of ceramic finds that offer insight into local pottery production traditions and their social and material contexts. Our preliminary analysis of both pottery and local clay and temper resources suggests that the community at Tuzusai engaged in feasting activities that incorporated a diverse vocabulary of pot forms. The overwhelming majority of these forms appear to have been locally produced using assembly strategies that responded to shortcomings in available raw materials. Given our current understanding of local production resources and the technical difficulty associated with the production of thin walled forms using these materials, we suggest that these ceramics may be high-status goods valued not solely for their function in feasting activities, but for the labor and skill required to produce them.

In this work, the exothermic reaction of the chemical energy storage material for stranded renewable energy, lithium is analyzed in carbon dioxide (CO2) and air. Spectroscopic techniques were used to characterize the reaction of bulk lithium pellets of up to 1 g weight. In comparison, power plant applicable combustion of atomized lithium spray was analyzed.

Electrical high voltage spark was used to overcome to activation energy of the combustion for the experiments with bulk lithium. The lithium spray was successfully ignited by pre-heating the reaction gases (air and CO2).

Radiation temperature of the bulk lithium during reaction in air was calculated to 2260 K. The observed green and red emission of the lithium combustion could be demonstrated in the spectral analysis.

In CO2 atmosphere the reaction products were found to be lithium carbonate with little lithium oxide. Beside, lithium carbide could be detected in the reaction product of the combustion of bulk lithium. The gaseous reaction product carbon monoxide (CO), which could be further converted with hydrogen from renewable sources to valuable methanol or gasoline, was detected online by gas analysis.

The present work addresses the systematic evaluation of the influence of the incorporation of dopant species (Ca+2, Ag+1) on the structural and functional properties of bismuth ferrite (BFO) nanocrystalline powders and films. Pure and doped BFO powders and thin films were synthesized by a modified sol-gel method. The concentration of the doping species varied from 0 up to 7 at %. The development of the host BFO structure was confirmed by XRD analyses of samples annealed at 700°C for one hour in air and nitrogen atmosphere. Thicknesses of films varied between 80 and 200 nm, depending on the concentration of Ca+2 species. Doped BFO exhibited a magnetic behavior that turned from paramagnetic into ferrimagnetic with the increase of Ca+2 concentrations.

Uniform and multilayered nanocomposites are of growing interest due to their desirable mechanical properties and their performance under high stress, wear, and impact conditions. Composite structures offer an opportunity to combine the useful properties from multiple materials. Controlled variations in composition and microstructure within a composite material allow for tunable local variations in properties. The simplest version of such a variation is to periodically change the composite volume fraction to create a multilayered composite material. Such structures would have hard layers to maintain strength and softer layers to allow for greater plasticity and prevent brittle failure. We are able to manufacture uniform and layered composites of nickel matrices embedded with alumina nanoparticles using electrodeposition. In this method a rotating disk electrode (RDE) is used to directly control the rate of particle incorporation. Uniform composites are made by holding a constant RDE rotation rate while layered composites are manufactured by periodically varying the rotation rate during deposition. We have demonstrated this novel manufacturing process for large-scale samples, several square centimeters in area and hundreds of microns thick, while maintaining submicron microstructural resolution.

The electronic properties of the interface between Rh clusters and CeO2 (111), (110) and (100) surfaces were studied using an isothermal-isobaric (NPT) ensemble at 773 K and 101.343 kPa using the tight binding-quantum chemical molecular dynamics (TB-QCMD) method. The amount of electronic exchange by interaction at the interface between the supported Rh55 clusters and each CeO2 surface was investigated quantitatively. A comparison of the mean square displacement (MSD) showed that the topmost oxygens on the Rh-supporting CeO2 surface exhibited higher mobility than those of the bare CeO2 surface. Although the mobility of the topmost oxygens on the bare CeO2 surface was in the order (100) > (110) > (111), this sequence was altered by the presence of Rh, so that the oxygen mobility for the more open (110) surface was the largest. The amount of electron exchange that occurred between Rh and the CeO2 (110) surface was also larger than for the (111) or (100) surface. The Ce 4f orbitals on the CeO2 (110) surface exhibited the strongest mixing with Rh 4d orbitals, which simultaneously caused restructuring and instability of the topmost Ce-O bonds. This enhancement of oxygen migration in the presence of Rh was occurred together with an increase in the number of oxygen vacancies on the ceria surface. This was because the topmost oxygens was shifted to have a stronger affinity with Rh and thus formed stronger bonds with Rh than with Ce.

Understanding crystal orientation at the ferroelectric domain level, using a non destructive technique, is crucial for the design and characterization of nano-scale devices. In this study, piezoresponse force spectroscopy (PFS) is used to identify ferroelectric domain orientation. The impact of crystal orientation on the switching field of ferroelectric BaTiO3 is also investigated at the domain level. The preferential domain orientations for BaTiO3 thin films prepared by pulsed laser deposition (PLD) in this study are [001], [101] and [111]. They have been mapped onto PFS spectra to show three corresponding switching fields of 460, 330 and 120 kV/cm respectively. In addition, the electric field at which the enhanced piezoresponse occurs was found to vary, due to a phase change. The polarization reversal occurs via a 2-step process (rotation and switching) for [101] and [111] orientations. The piezoresponse enhancement is absent for the [001] (pure switching) domains. The results demonstrate that an electric field induced phase change causes the [101] and [111] domains to reverse polarization at a lower field than the [001] domain.

The occurrence of Atmospheric chloride-Induced Stress Corrosion Cracking (AISCC) under wetted deposits of MgCl2 or sea-salt at 70°C has been investigated at various Relative Humidities (RH). The appearance of AISCC is a function of the environmental RH. At 33% RH (the deliquescence point of MgCl2), AISCC generated under MgCl2 or sea-salt deposits is of a similar appearance with regards to the number of cracks produced and average crack length. At 50% RH sea-salt seems to be more aggressive at least in terms of crack frequency. This observation may highlight the significance of carnallite (KMgCl3.6H2O) in promoting AISCC in types 304L and 316L stainless steels. The use of accelerated testing methods to validate apparent thresholds in chloride deposition density and other critical factors that influence the initiation and propagation of AISCC is briefly discussed.

Molecules such as dithiols are of significant interest for potential molecular electronics applications. To investigate their properties, an efficient method for measuring their electrical conductance is crucial. This research focuses on the time domain measurement, a novel technique capable of measuring hundreds of molecules within a matter of seconds. Measurements were conducted using STM with the tip positioned within tunneling distance over a SAM of 1,8-octanedithiol on Au(111)-mica substrate submerged in toluene. Bonding/debonding events between the tops of molecules and the tip were observed through jumps in the time domain current waveform. A new time-spent histogram data analysis technique was developed to extract conductance values from complex waveforms. Conductance of 2.6 nS was obtained for a single 1,8-octanedithiol molecule, consistent with results obtained from wellestablished but time consuming break junction technique, validating the new STM based time domain technique for fast measurement of molecular conductance.

In the present study a new sandwich laminate is designed and mechanically characterized. The laminate is elaborated with a core of particulate composite material consisting of recycled material from milk and juice cartons (multilayer laminate of Tetra Brik® ), and HDPE containers from Urban Solid Waste (USW). The elaborated material consists of aluminum facings with a particulate core, consolidated with a thermoplastic adhesive of polypropylene- maleic anhydride. The main properties under tension are evaluated under testing standards. Results show good compatibility in the union of elements, with potential applications in building facades and false walls for the construction and furnishing industries.

Bacterial infections are commonly found on paper towels and other paper products leading to the potential spread of bacteria and consequent health concerns. The objective of this in vitro study was to introduce antibacterial properties to paper towel surfaces by coating them with selenium nanoparticles. Results showed that the selenium nanoparticle coated paper towels inhibited the growth of S. Aureus and P. aeruginosa by 80%∼90% after 72 hours compared with the uncoated paper towels. Thus, the study showed that nano-selenium coated paper towels may lead to an increased eradication of bacteria to more effectively clean a wide-range of clinical environments, thus, improving health.

Fibrin hydrogels are an exciting platform for cell-based therapies, as they contain necessary cues for adhesion, can be remodeled by entrapped cells, and the biophysical properties can be modified with a plethora of strategies. Furthermore, fibrin acts as a provisional matrix in vivo for tissue regeneration. While the majority of studies seek to manipulate fibrin gel properties by changing the concentration of clotting proteins, these studies highlight our capacity to change bulk stiffness and fiber properties by supplementing the solutions with sodium chloride (NaCl). Physical properties including fiber thickness, porosity, compressive modulus, and fluid uptake capacity were dependent on NaCl content, with gels containing 2.60% (w/v) NaCl exhibiting compressive moduli threefold higher than gels without NaCl. These material properties, in turn, affected the gel morphology along with the osteogenic and pro-angiogenic response of entrapped mesenchymal stem/stromal cells (MSCs). The osteoconductivity of fibrin gels can be enhanced by inclusion of apatite-coated polymer substrata to nucleate mineral, while the efficacy of engineered fibrin gels to simultaneously deploy small molecules with cells to enhance endogenous angiogenic potential has been demonstrated. Collectively, these data demonstrate the broad capacity of engineered fibrin gels to regulate function of entrapped cells for use in tissue engineering and regenerative medicine.

A simple methodology to electrodeposit thin soft CoFe films with desirable microwave properties from simple salt solutions at room temperature is demonstrated. Plating solution parameters have diverse influences on real potentials of ion reductions and deposition behavior of the FeCo crystals, consequently affecting largely the particle size, crystal structure and chemical composition of the film fabricated. This in turn determines their static magnetism and dynamic microwave properties. Through optimizing solution additive, concentration and temperature from electrodeposition mechanism, the as-prepared nanofilms possess a low coercivity of < 30 Oe, moderate anisotropy of 60-90 Oe, high crystallinity and magnetic moment of ≥ 2.0 T, and hence readily display an ultrahigh magnetic permeability (up to 1128) and resonant frequency (up to 2.1 gigahertz) simultaneously, as well as other desirable physico-chemical properties. Thus the nanofilms can be applied to high gigahertz frequency applications.

This study demonstrates the development of a zinc oxide (ZnO) based microelectrode sensor for the ultra-sensitive detection of protein biomarkers. Our research focuses on utilizing a materials-based approach to achieve this objective by utilizing ZnO as part of our biosensor for (1) improved surface binding to enhance sensitivity and (2) creating a nanotextured surface for enhanced output signal response. Nanotextured ZnO thin films were integrated onto printed circuit boards using RF magnetron sputter deposition. Films sputtered with and without the presence of oxygen were examined for possible differences in biosensor efficacy. These fabrication conditions not only dictate the number of oxygen vacancies within the film but also regulate the amount of zinc and oxygen terminated ends occurring on the material surface. The correlation between the surface terminations of the nanotextured ZnO to its performance as a biosensor was evaluated using two cross-linker molecules, dithiobis succinimidyl propionate and (3-aminopropyl)triethoxysilane, that maintain different binding chemistries to ZnO. Qualitative and quantitative assessment of cross-linker binding was accomplished using fluorescent microscopy and fluorescent intensity measurements. Electrical impedance spectroscopy (EIS) was used as the transduction mechanism for detection of the well-established cardiac biomarker, troponin-T. Utilizing EIS with a functionalized immunoassay on the ZnO surface, troponin-T was detected as low as 10 fg/mL using ZnO films sputtered without oxygen. This enhanced detection of the cardiac biomarker can be directly attributed to 1) oxygen vacancies within the metal oxide film, 2) the nanotexturing of the sensing site surface, and 3) the ability to bind a significant amount of cross-linker molecules for immobilizing capture antibodies.

The MIAMI* facility at the University of Huddersfield is one of a number of facilities worldwide that permit the ion irradiation of thin foils in-situ in a transmission electron microscope. MIAMI has been developed with a particular focus on enabling the in-situ implantation of helium and hydrogen into thin electron transparent foils, necessitating ion energies in the range 1 – 10 keV. In addition, however, ions of a variety of species can be provided at energies of up to 100 keV (for singly charged ions), enabling studies to focus on the build up of radiation damage in the absence or presence of implanted gas.

This paper reports on a number of ongoing studies being carried out at MIAMI, and also at JANNuS (Orsay, France) and the IVEM / Ion Accelerator Facility (Argonne National Lab, US). This includes recent work on He bubbles in SiC and Cu; the former work concerned with modification to bubble populations by ion and electron beams and the latter project concerned with the formation of bubble super-lattices in metals.

A study is also presented consisting of experiments aimed at shedding light on the origins of the dimensional changes known to occur in nuclear graphite under irradiation with either neutrons or ions. Single crystal graphite foils have been irradiated with 60 keV Xe ions in order to create a non-uniform damage profile throughout the foil thickness. This gives rise to varying basal-plane contraction throughout the foil resulting in almost macroscopic (micron scale) deformation of the graphite. These observations are presented and discussed with a view to reconciling them with current understanding of point defect behavior in graphite.

*Microscope and Ion Accelerator for Materials Investigations

In this study, we have investigated various approaches to improve CIGS solar cells after thin film deposition. CIGS devices have been fabricated by a hydrazine solution based process. Post-deposition treatments by sulfurization were studied with focuses on the change of material structures and physical properties. Sulfurization has shown to increase grain size and band gap of the absorber layers at higher temperatures. This property change has shown a direct impact on open circuit voltage of the solar cell devices. Through these post-deposition processes, improved quality of CIGS materials can be obtained and the associated solar cell devices show better performance.

In this paper, the effect of phosphorus diffusion and hydrogen passivation on the material properties of laser crystallised silicon on glass is investigated. Photoluminescence imaging, as well as Hall effect and Suns-Voc techniques are applied for the characterisation of laser crystallized silicon thin-film material properties. Hall effect as well as Suns-Voc measurements supports the photoluminescence imaging results; phosphorus diffusion and hydrogen passivation of laser crystallized films improves the overall material quality. Hydrogen passivation is more effective at improving the electronic properties of the laser crystallized films than phosphorus diffusion. Hydrogen passivated samples improved the photoluminescence intensity even further by a factor of 3. In addition, a correlation between photoluminescence intensity and open-circuit voltage is demonstrated: samples with highest photoluminescence intensity (1678 counts/s), gave the highest voltage (530 mV). Hall effect measurement shows a significant improvement in the bulk material, with carrier mobility increasing from 208 cm2/Vs to 488 cm2/Vs.

Study on oxidizing cellulose scaffold to dialdehyde cellulose by sodium periodate (NaIO4) was carried out. Concentration of sodium periodate and the reaction time were effected for aldehyde introduction to cellulose scaffolds. Cellulose powder was dissolved in 1-butyl-3-methylimidazolium chloride, an ionic liquid, at 100°C and maintained at room temperature for 7 days, providing flexible cellulose scaffold. The cellulose scaffold was oxidized using periodate oxidation (Malaprade oxidation), which oxidizes carbohydrate by glycol cleavage to provide dialdehyde. Aldehyde groups introduced into cellulose were quantified by simple iodometry. Oxidized cellulose scaffold was degraded in the amino acid solution triggered by the reaction between aldehyde groups and amino groups. During immersion of the cellulose scaffolds in the amino acid solution, the mass loss of the scaffolds was evaluated by measuring of weight of oxidized cellulose scaffold before and after degradation.

Crystal plasticity finite element method is a useful tool to investigate the anisotropic mechanical behaviors as well as the microstructure evolution of metallic materials and it is widely used on single crystals and polycrystalline materials. However, grain boundary involved mechanisms are barely included in the polycrystalline models, and modeling the interaction between the dislocation and the grain boundaries in polycrystalline materials in a physically consisstent way is still a long-standing, unsolved problem. In our analysis, a dislocation density based crystal plasticity finite element model is proposed, and the interaction between the dislocation density and the grain boundaries is included in the model kinematically. The model is then applied to Al bicrystals under 10% compression to investigate the effects of grain boundary character, e.g. grain boundary misorientation and grain boundary normal, on the stress state and the microstructure evolution. The modeling results suggest a reasonable correspondence with the experimental result and the grain boundary character plays a crucial role in the stress concentration and dislocation patterning.

A Joule heating based self-alignment method for solution-processable insulator structures has been modeled for the passivation of metal grid lines, for example for organic light emitting diodes or photovoltaic cells. To minimize overhang of the passivation layer from line edges, we have studied the Joule heating approach using solution-processable, cross-linkable polymer insulator films. Finite element simulations were performed to investigate the heating of the sample using glass and poly(ethylene terephthalate) (PET) substrates. The sample was at room temperature and the current was selected to induce a temperature of 410 K at the conductor. It was found that the selection of substrate material is crucial for the localization of cross-linking. For a PET substrate, the temperature gradient at the edge of the conductor is approximately twice the gradient for glass. As a result, using a glass substrate demands high selectivity from the polymer cross-linking, thus making PET a more suitable substrate material for our application. A flexible PET substrate is, in addition, compatible with roll-to-roll mass-manufacturing processes.