Mechanical properties similar to natural bone and good biocompatibility make magnesium a great option for its use as biodegradable implant material. The use of castings as fabrication technique brings inherent problems, such as segregation and void formation. Also, the architecture of the specimens created by using these techniques is limited. This study shows the implementation of WAAM for the fabrication of elements made out of AZ91D magnesium alloy (9% aluminium and 1% zinc). The results demonstrate that porosity or cracking only appears at the surface of the individual printed lines, while the central sections presents a void-less structure composed by an HCP magnesium matrix and a high density of well dispersed aluminium-zinc rich precipitates. EDS mapping confirms the presence of orthorhombic Al5Mg11Zn4 phase. Also, the relationship between the heat present in the system and the morphology of the lines is analysed.

Poly (methyl methacrylate)/hydroxyapatite (PMMA/HAp) nanocomposites with HAp nanoparticles content of 12 wt.% were obtained by free-radical polymerization synthesis. Three different concentrations of benzoyl peroxide (PBO) of 3, 6, and 12 wt.% were studied. The results showed that the concentration of PBO has an effect on the performance of composites. In particular, the nanocomposite with the highest concentration of PBO presented the best mechanical and tribological behavior, as well as the lowest values of water absorption and porosity percent.

Time correlations of dynamic variables in the reciprocal space offer a rich theoretical setting for computing the phonon dispersion curves, particularly for systems with marked anharmonic interactions. Present techniques primarily rely either on the equipartition of energy between the phonon modes or on the oscillation of the time correlation of the normal mode projections. The former can lead to numerical errors due to deviation from equipartition while the latter usually requires long simulations for computing the time correlations. We investigate a different approach using the ratio of the normal mode expectation value of two conjugate variables – velocity and acceleration. Since only the correlations at the initial time (t=0) are needed, this approach is computationally attractive. In this work, we employ this method to extract the full Brillouin zone phonon dispersion for graphene.

The phase diagram of LiF-Li3PO4 system is studied. The eutectic coordinates are 800±5°C, 8±1 mol% Li3PO4. A region of a solid solution based on lithium phosphate with a length of up to 11±2 mol% LiF was discovered. It is assumed that there is heterovalent isomorphism where anionic tetrahedron (PO4)3- is replaced by tetrahedron (LiF4)3-.

Clinoptilolite modified with polypyrrole and iron oxide nanoparticles (Cln-PPy-Fe3O4) nanocomposite as a potential adsorbent for V (V) ions was prepared via polymerization of pyrrole monomer using FeCl3 oxidant in aqueous medium in which clinoptilolite-Fe3O4 nanoparticles were suspended. The structure and morphology of the prepared adsorbent was analysed with the Fourier transform infrared (FTIR) spectrometer, field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and high-resolution transmission electron microscope (HR-TEM). Column fixed bed studies were performed to test the ability of the adsorbent to remove V (V) ions from aqueous solution. Low values of adsorbent exhaustion rate (AER) and large bed volumes were observed at lower metal ion concentration, higher bed mass and lower flow rate for V(V) removal indicating good performance. The volume of treated water processed at breakthrough point were found to be 0.09; 0.63 and 1.26 L for bed mass of 1, 2.5; and 5 g, respectively. The Yoon–Nelson and Thomas models appropriately described the breakthrough curves.

In this work, we report on fabrication of the thin-films of silicon oxide dielectric layers on silicon with back-side contact and utilization of the structure to study the detection of human Troponin antigen (cTnI) molecules: the cardiac biomarkers for the early diagnosis of acute myocardial infraction. Aptamers are selectively bound to the target molecules and can block the binding epitope for further reaction like immobilization or interaction to any other molecules. In contrast to antibodies, the aptamers are smaller in size, which allows target molecules to be brought closer to the surface of the biosensor and, therefore, to enhance the molecular signal. The target molecule in this work is cTnI, which is located in the cardiac muscle tissue. As a reliable indicator of heart failure and injury, it is specifically considered for the diagnosis of myocardial infarctions. The solutions of Troponin molecules were studied in different concentrations range from 10 pg/μL to 1 ng/μL. For the electrical detection of cTnI, we used the field-effect capacitive electrolyte-insulator-semiconductor (EIS) technique, which is a robust method for the quantitative characterization of molecular layers. The measured values of capacitances and flat band voltages were used to acquire information about the properties of the molecular layers obtained using solutions with different troponin concentrations. It was shown that this method demonstrates high sensitivity to target cardiac biomolecules and opens up new perspectives for highly selective and sensitive cardiac biosensors developed on the basis of silicon nanowire structures.

Collaborations between community colleges, non-research centered universities and research universities can enrich the flow of students into Science, Technology, Engineering and Mathematics (STEM) majors and careers. The nation is beginning to understand the importance of such interaction especially with under-represented minorities and those with disabilities. For over fifteen years our group has developed new ways to integrate these students and their faculty to the research culture. This will lead to increased diversity and inform research university faculty of the great talent that is latent in these underserved pools.

Overpotential losses on cathode during oxygen reduction reaction (ORR) causes serious performance depletion in microbial fuel cells (MFCs). High cost of existing platinum based noble catalysts is one of the main reason for growing interest in the research of low cost sustainable cathode catalysts to improve ORR in order to enhance power generation from MFCs. The present study demonstrates application of low-cost bimetallic ferrite, Co0.5Zn0.5Fe2O4, as a cathode catalyst in MFC. The electrochemical tests of cathode having this catalyst revealed an excellent cathodic current response of 25.76 mA with less charge transfer resistance of 0.7 mΩ, showing remarkable catalytic activity. The MFC using this catalyst on cathode could generate a power density of 172.1 ± 5.2 mW/m2, which was found to be about 10 times higher than the power density of 15.2 ± 1.3 mW/m2 obtained from a MFC using only acetelyne black (AB) on cathode and noted even higher than the power density produced by MFC with Pt/C cathode (151.3 ± 2.8 mW/m2). In addition, the wastewater treatment in terms of chemical oxygen demand (COD) removal efficiency of MFC with Co0.5Zn0.5Fe2O4 on cathode was found to be better (87 %) among the tested MFCs. Hence, the results obtained from this study illustrates the applicability of Co0.5Zn0.5Fe2O4 as an excellent and suitable cathode catalyst for scaling up of MFCs.

In Finland and Sweden the KBS-3 concept has been chosen for the disposal of spent nuclear fuel in crystalline rock. Recent experiments have shown that heterogeneity of rock may play a major role in the transport of radionuclides. Autoradiographic methods have been proven to be able to assist the characterization of heterogeneous structures. In this study we tested a novel filmless autoradiographic device called BeaverTM which applies a micro patterned gaseous detector in order to quantitatively map beta emissions from C-14 atoms. The studied samples were impregnated with C-14-labelled methylmethacrylate (C-14-MMA) and polymerized to C-14-PMMA with thermal initiator. The BeaverTM was then used to determine the spatial distribution of the C-14-PMMA by measuring the C-14 emissions. The porosity is determined from the amount of C-14-PMMA in the rock sample and results were compared to ones from phosphor imaging plate autoradiography. The resulting images show a heterogeneous distribution of porosity which arises from the different minerals. The samples were chosen from three sites that have been used recently for in situ diffusion experiments: Olkiluoto (Finland), Äspö (Sweden) and Grimsel (Switzerland).

In this work, we present the results of investigation of the nanoporous material – carbon fabrics, which is used as electrodes in rechargeable energy storage capacitors (ultracapacitors). The impurity composition in the fabrics, the influence of thermal annealing conditions on the impurity concentration is studied. The performed studies resulted in determination of the investigated carbon material structure, determination of impurity composition of carbon material and change of impurity content depending on thermal treatment in vacuum at different temperatures and time intervals. The optimum temperature range for the treatment of carbon fabrics in vacuum that is important for its application in energy storage devices is found.

The effect of ions on the structure and dynamics of aggracan solutions was investigated using a variety of scattering techniques (neutron spin echo, small angle neutron scattering, static and dynamic light scattering). The results show that aggrecan forms microgel-like assemblies which remain stable in the presence of counter-ions. As opposed to many synthetic polyelectrolytes which exhibit a great sensitivity to ion concentration and charge valency, it was found that aggrecan solutions are remarkable insensitive to charge valence. This property of aggrecan is consistent with its biological role as an ion reservoir mediating calcium metabolism and maintaining dimensional stability in cartilage and bone.

Composite of PZT (lead zirconate titanate) and PLZT (lead lanthanum zirconate titanate) along an organic, renewable, conductive, and flexible matrix have been developed. The conductive paper was obtained through the reaction between the cellulose extracted from banana stem and functionalized MWCNT. This reaction was made in the presence of hydrogen (from H2SO4), which reduced the size of the cellulose by acid hydrolysis and promotes the interaction between its hydroxyls and the carboxyl groups of nanotubes. Afterward, the PZT particles were synthesized and grown up on the conductive paper by microwaves-assisted hydrothermal synthesis (MHS). The composite material was characterized by structure and morphology. Moreover, gas-sensing in the presence of methanol and electrical resistance as a function of temperature were also investigated. In this way, a simple, low-cost and successful synthesis was reported. Also, a promising flexible was obtained using a chemical transformation process from banana residue as source of cellulose.

Nuclear energy is one option to meet rising electricity demands, although one concern of this technology is the proper capture and storage of radioisotopes produced during fission processes. One of the more difficult radioisotopes is 129 I due to its volatility and poor solubility in traditional waste forms such as borosilicate glass. Iodosodalite has been previously proposed as a viable candidate to immobilize iodine due to high iodine loading and good chemical durability. Iodosodalite was traditionally synthesized using solid state and hydrothermal techniques, but this paper discusses an aqueous synthesis approach to optimize and maximize the iodosodalite yield. Products were pressed into pellets and fired with glass binders. Chemical durability and iodine retention results are included.

Thermal resistance across the interface between touching surfaces is critical for many industrial applications. We developed a network model to predict the macroscopic thermal resistance of mechanically contacting surfaces. Contacting interfaces are fractally rough, with small islands of locally intimate contact separated by regions with a wider gas filled boundary gap. Heat flow across the interface is therefore heterogeneous and thus the contact model is based on a network of thermal resistors representing boundary resistance at local contacts and the access resistance for lateral transport to contacts. Molecular dynamics simulations have been performed to characterize boundary resistance of Silicon Alumina interfaces for testing the sensitivity of thermal resistance to contact opening. Boltzmann transport simulations of access resistance in Si are conducted in the ballistic transport regime.

Chlorophenols are among the priority listed water contaminants due to their estrogenic, mutagenic or carcinogenic health effects. The Ag/ZnO nanocomposites (NCs) were synthesized, characterized and tested for photacatalytic degradation of chlorophenols in water. The synthesis was done using zinc nitrate hexahydrate (ZnNO3. 6H2O) precursor and sodium hydroxide (NaOH). Silver nitrate (AgNO3) was added to ZnO and reduced with sodium brohydride to produce the silver nanoparticles (NPs) within the ZnO structure. The silver content was varied from 1, 3 and 5wt% for optimisation. The nanocomposites were characterised using ultraviolet - visible spectroscopy (UV-Vis), photolumniscence (PL), x-ray diffraction (XRD), and scanning transmission electron microscopy (STEM). The nanocomposites were tested for their photocatalytic properties on 2- chlorophenol (CP), 2- chlorophenol (CP) and 2,4- dichlorophenol (DCP) in water. The UV-Vis results showed that, as the amount of silver was increased a gradual slight red shift was observed. The XRD patterns for Ag/ZnO exhibited peaks that were characteristic of the hexagonal wurzite structure and peaks characteristic for Ag appeared at 38.24o, 44.37o, 64.67o and 77.58o corresponding to (111), (200), (220) and (311) reflection planes. STEM results showed the presence of Ag in ZnO with ZnO appearing as rods shapes. The EDX elemental analysis confirmed the presence of Ag in the Ag/ZnO nanocomposites with no contaminants peaks. On testing the nanocomposites for phohotocatalytic degradation of chlorophenols, addition of Ag to ZnO improved degradation of the chlorophenols compared to the pristine ZnO.

We present on the optical and electronic properties of a fungi-derived pigment xylindein for potential use in (opto)electronic applications. Optical absorption spectra in solutions of various concentrations and in film are compared and are consistent with aggregate formation in concentrated solutions and films. In order to improve film morphology obtained by solution deposition techniques, an amorphous polymer PMMA was introduced to xylindein to form xylindein:PMMA blends. Current-voltage characteristics and hole mobilities extracted from space-charge limited currents were found to be comparable between pristine xylindein and xylindein:PMMA films. Side by side comparison of the photoresponse of pristine xylindein and xylindein:PMMA films at 633 nm revealed an increase in the photosensitivity in xylindein:PMMA films due to the improved morphology favouring enhanced charge generation.

Despite being one of the oldest phenomena known to mankind and its vast use, there still are open questions about the frictional process between two surfaces, especially at the nanometer scale, such as the energy dissipation mechanism, the influence of the crystallographic orientation and the correlation between macroscopic and microscopic scales. In this work, we analyze the interaction between a sharp tip and graphene by friction force microscopy. The graphene surface roughness and adhesion forces with the microscope tip were measured. Neither roughness nor adhesion were observed to influence the friction forces. The scanning velocity dependence of friction was also measured for a different number of layers. The friction forces were observed to increase with the scanning velocity until a critical velocity is achieved by which we have estimated the effective interaction potential between the tip and the graphene surface.

The effects of Ag nanoparticles on microorganisms and the antimicrobial mechanism has recently been validated for different microbiological strains, as well as their cytotoxic effect in in vitro cellular models. In this work we report the synthesis of Ag nanoparticles using the extract of Eichhornia crassipes as reducing agent, and evaluated its antimicrobial activity with Escherichia coli. The morphology, size and inhibition properties of the nanoparticles as a function of the reduction time in the chemical synthesis were analyzed. The characterization was carried out by UV-Vis spectrophotometry and transmission electron microscopy. Nanoparticles with average diameters of 40 nm ± 10 nm were obtained and their antimicrobial activity with higher inhibition in Escherichia coli was recorded with the nanoparticle samples obtained at 120 min. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to various medical devices and antimicrobial control systems by modifying their concentration.

Increasing the operation voltage of LiCoO2 (LCO) is a direct way to enhance the energy density of the Li-ion batteries. However, at high voltages, the cycling stability degrades very fast due to the irreversible changes in the electrode structure, and formation of an unstable solid electrolyte interface layer. In this work, Ag thin film was prepared on commercial LCO cathode by using magnetron sputtering technique. Ag coated electrode enabled an improved electrochemical performance with a better cycling capability. After 100 cycles, Ag coated LCO delivers a discharge capacity of 106.3 mAh g-1 within 3 - 4.5 V at C/5, which is increased by 45 % compared to that of the uncoated LCO. Coating the electrode surface with Ag thin film also delivered an improved Coulombic efficiency, which is believed to be an indication of suppressed parasitic reactions at the electrode interface. This work may lead to new methods on surface modifications of LCO and other cathode materials to achieve high-capacity Li-ion batteries for high-voltage operations.