Graphene Quantum Dots (GQDs) are of interest to the biomedical community due to their unique fluorescence properties, which may be advantageous for biology and medicine. Advantages of this graphene nanomaterial over fluorescent dyes for biomedical imaging include bright emission, easy surface modification, biocompatibility, and anticipated low toxicity. We hypothesize that GQDs with desirable fluorescence properties which can be used for effective biomedical imaging (such as near infrared emission) may be synthesized from cheap carbon sources. Here, we show that these fluorescent GQDs are fabricated in a facile wet chemistry route using activated charcoal as the starting material. The GQDs were characterized with AFM, TEM, FTIR, PL spectroscopy, Raman spectroscopy and animal imaging techniques. The particles were visible in animals indicating their potential for biomedical imaging. The GQDs exhibited excitation that spanned the UV and visible ranges and emission that spanned the visible and near infrared ranges. The GQDs were an average of 4 nm in height, crystalline, from 1 to 60 nm in size. The GQDs were consistent with the presence of graphene and the following functional groups: C-O, C-H, C=C, and CO2H. In conclusion, GQDs with favorable photophysical properties can be produced from affordable and widely available raw materials for imaging and other biomedical application purposes.

X-ray beam-induced damage in nanoscale metal islands was investigated. Monolayer-high Ni islands were prepared on a Cu(111) substrate. High brilliance X-rays with photon energies between 8.45 and 8.85 keV illuminated the sample for about 11 hours. In order to track changes in the morphology of the islands, the synchrotron X-ray scanning tunneling microscopy (SX-STM) technique was utilized. The result shows that X-ray illumination onto Ni islands does not induce noticeable damage. The study demonstrates that local beam-induced changes can be studied using SX-STM.

We studied the pulmonary toxicity of indium hydroxide (In(OH)3), which is produced during a recycling process of indium-tin oxide (ITO), in comparison with that of ITO or indium oxide (In2O3), two raw materials of flat panel displays. One hundred and forty-four male Wistar rats were intratracheally given equivalent doses of 10 mg/kg indium as In(OH)3, ITO, or In2O3 particles, twice a week, for a total of 5 times for 2 weeks. Control rats were given distilled water as a vehicle. After 3 weeks, these rats were serially euthanized, and toxicological effects were determined. Body weight gain was significantly suppressed in the In(OH)3-treated rats compared to that in the control group, but not in the ITO- or In2O3-treated rats. Relative lung weights in all the indium-treated groups significantly increased compared to those in the control group throughout the observation period. Furthermore, lung weights in the In(OH)3 group were significantly higher than those in either the ITO or In2O3 group. Blood indium levels in the In(OH)3-treated rats were much higher, 70- to 200-fold, than those in the In2O3- or ITO-treated rats at each time point. Although the lung indium content decreased gradually during the observation periods, the content in the In(OH)3 group was significantly higher than that in either the ITO or In2O3 group. A histopathological analysis revealed foci indicating a slight to severe pulmonary inflammatory response, including exudation to alveolar spaces, were present in all the indium-treated groups. Interstitial fibrotic proliferation was seen only in the In(OH)3-treated rats. The severity of these lesions in the In(OH)3-treated rats was greater than that in either the ITO- or In2O3-treated rats.

The results of our study clearly demonstrated that In(OH)3 particles caused severe pulmonary toxicity when repeated intratracheal instillations were performed in rats. Furthermore, the toxic potency of In(OH)3 in the lung was much higher than that of ITO and In2O3. Accordingly, the toxicity of In(OH)3 particles should be considered in addition to that of ITO and In2O3 particles when indium exposure occurs.

Salinity gradient is an enormous source of clean energy. A process for potential generation from an ionic concentration gradient produced in single and multicell assembly is presented. The ionic gradient is created using a fuel cell type cell with a micro-porous ion exchange membrane, both anionic (AEM) and cationic (CEM). Various salinity gradients, Salt : Fresh, from 100 : 0 to 16000 : 0 was established using NaCl solution, in the electrode chambers. A potential of 20 mV/cm to 25 mV/cm can be realized at ambient temperatures and pressures for a bipolar AEM/CEM cell. The performance was optimized for various static and dynamic flow rates of the saline and fresh water. The cell performance can further be optimized for Membrane Electrode System (MES) morphology. A multicell unit was assembled and the results presented for various conditions like concentration gradients, flow rates and pressure. The thermodynamic and electrical efficiency needs to be evaluated for various gradients and flow rates. The relation with number of valance electrons/ ion and the potential generated changes for various dynamic condition of salinity. The higher the salinity gradient the larger is the potential generated. This is limited by the membrane characteristics. There exists a monotonic relation between the number of valence electron/ion/unit time and the potential generated up to about 16000 concentration. The membrane characteristics have been studied for optimal ion crossover for various gradients and flow. The graph between ln (gradient) versus Voltage provides insights into this process. This presents a very cost effective and clean process of energy conversion.

In recent decades, we have seen an increase in the use of computers. This presents a crossroads in deciding what to do with the units that become "obsolete". As society, we have created a new type of solid waste that must be handled differently because the diversity of materials composition. In addition, at the end of their life cycle also affects the environment when the materials are disposal in landfill; i.e. plastic substrate (polycarbonate), may lead to chronic problems such as hyperactivity, infertility or even cancer.

The recycling of electronic equipment is from whole parts, such as the electronic cables. Recover substances (plastics) and compounds (metals) from electronic cables could it be possible.

We are looking for a solution to this problem and we created a structure of recycling to reduce the waste at the source and allows that which cannot be reduced is recycled, because computers contain 20% of thermoplastics and 6% of plastic mixtures that are the subject of this investigation.

The recycled chemist hired himself since it provides capabilities that address the limitations of the mechanical recycling; you need large quantities of clean, separate, homogeneous plastic waste to be able to guarantee the quality of the final product. Chemical recycling overcomes these drawbacks, since the classification of the different types of plastic resins from of waste is not necessary.

Based on the data obtained from this research, determines that the recycling of computer waste in conjunction with other plans of reduction at source makes this a viable alternative for the management of the same. Benefits that can be derived by establishing a recycling of the computer waste program is donating units or sell these affordable to low-income people who otherwise would not have access to this technology.

Thermal transport across interfaces is an important issue for microelectronics, photonics, and thermoelectric devices and has been studied both experimentally and theoretically in the past. In this paper, thermal interface resistance (1/G) between aluminum and silicon with nanoscale vacancies was calculated using non-equilibrium molecular dynamics (NEMD). Both phonon-phonon coupling and electron-phonon coupling are considered in calculations. The results showed that thermal interface resistance increased largely due to vacancies. The effect of both the size and the type of vacancies is studied and compared. And an obvious difference is found for structures with different type/size vacancies.

The reverse martensitic (austenite) transformation temperatures (A s) were investigated using a diffusion couple of PtTi and CoTi with a continuous compositional gradient. It was found that PtTi and CoTi form a complete solid solution of (Pt, Co)Ti at 1373K. Surface relief was formed by heating due to the austenite transformation. Judging from the formation of the surface patterns and the corresponding chemical compositions, A s monotonously decreases with increasing Co content at a rate of -70K/at%Co, and A s is estimated to be close to room temperature (RT) when the Co concentration is 15at%Co. Besides, micro Vickers hardness values measured at RT are minimized around 15at%Co.

This investigation introduces a new very simple and efficient approach for QCM sensor response amplification, developed for hydrolases activity determination. For this purpose, the QCM crystal surface was modified with nanoparticles loaded enzyme substrate. During the enzymatic substrate degradation, the heavier nanoparticles were also released from the sensitive layer together with the substrate degradation products. Nanoparticles removal resulted in QCM signal amplification due to the higher nanoparticles specific mass compared with the specific mass of the substrate.

The suggested concept was successfully applied for creating of simple biosensing platforms for trypsin and lipase activity determination in real time using respectively SiO2 nanoparticles loaded olive oil and Ag nanoparticles loaded gelatin as enzyme substrates. Up to 10 times amplification of the QCM signal was reached applying the proposed approach compared with the common one.

Extended research has been developed in the use of wheat straw (WS) as biomass for the production of biofuels (bioethanol), including the processes of degradation of cellulose by enzymatic systems. For centuries, Cellulose has been used by man; however, its enormous potential as a renewable energy source was recognized only after the discovery of cellulose degrading enzymes (cellulases). A wide variety of microorganisms can produce cellulolytic enzymes under appropriate culture conditions and among these microorganisms are filamentous fungi of the genera Trichoderma, Aspergillus, Penicillium and Fusarium. The purpose of this study was to produce cellulase enzyme from previously isolated and characterized filamentous fungi. Cellulytic fungi belonged to Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Penicillium chrysogenum, Penicillium sp., and Trichoderma harzianum. All these strains were preserved by lyophilization and also kept in sterile media (sand and soil) at 4 °C. The production of cellulases by submerged fermentation was performed in a Mandels mineral medium. The nitrogen sources were urea and ammonium sulfate. Glucose alone was used in the pre-inoculum, and dried and ground wheat straw was used in the fermentation as carbon sources. Subcultures of spore suspensions were incubated with orbital stirring (120 rpm) at 30 °C for 48 hours and used as inoculum for submerged fermentation with wheat straw as substrate in mineral medium with an initial pH of 5. Activity cellulase was determined by the method of 3,5-dinitrosalicylic acid (DNS). The results showed that wheat straw have potential for use as a substrate in the production of cellulases. Aspergillus niger showed the highest enzymatic activity from the cellulase produced 0.051 FPU (filter paper units) after 96 hours of fermentation.

Sodalite (Na8[AlSiO4]6Cl2), a naturally occurring Cl-containing mineral, has long been regarded as a potential immobilization matrix for the chloride salt wastes arising from pyrochemical reprocessing operations, as it allows for the conditioning of the waste salt as a whole without the need for any pre-treatment. Here the consolidation and densification of Sm-doped sodalite (as an analogue for AnCl3) has been investigated with the aim of producing fully dense (i.e. > 95 % t.d.) ceramic monoliths via conventional cold-press-and-sinter techniques at temperatures of < 1000 °C. Microstructural analysis of pressed and sintered sodalite powders under these conditions is shown to produce poorly sintered, porous, inhomogeneous pellets. However, by the addition of a sodium aluminophosphate glass sintering aid, fully dense Sm-sodalite ceramic monoliths can successfully be produced by sintering at temperatures as low as 800 °C.

In this work it was conducted a pre heat treatment of a number of samples of alumina with organic binder in order to remove most of the organic phase. The treatment showed no effect on the physical properties of test specimens; green bodies remained stable during sintering process. Preheating at 100 °C for 4 h followed by heating at 300 °C for 4 h were the most favorable conditions to avoid formation of defects in the sintered pieces.

Due to its wide band-gap, Al2O3 is known to have a moderate leakage current and a good dielectric strength [1]. Moreover, this dielectric has a fair permittivity and so constitutes interesting candidate as dielectric for Metal-Insulator-Metal (MIM) capacitor. Atomic Layer Deposition (ALD) allows obtaining a dense and thin Al2O3 amorphous layer. ALD limits problems of interlayer diffusion because Al2O3 is deposited underneath 400°C [2] which is essential when MIM are co-integrated with temperature sensitive structures.

The aim of our investigation is to attempt to tie aluminum oxide properties dielectric with reliability from the help of capacitors of the entire wafer. In this way, conduction mechanism analysis and capacitance measurements were statistically led on the wafer. We particularly focus our study on the quantification of defects and their influence on the leakage current in planar capacitor. Firstly, to estimate the fixed oxide charges densities in the bulk of Al2O3 and to analyze conduction mechanism, Metal-Oxide-Semiconductor (MOS) (Al/Al2O3/HR-Si) is developed. Then, a MIM stack (Al/TiN/Al2O3/TiN/HR-Si) is developed in order to evaluate the leakage current and the electrical reliability of thin films Al2O3 based MIM capacitors. Different performances are observed according to the area on the wafer. That could be explained by the quality of the Al2O3 layer and the interfaces between TiN and the oxide.

The high carrier concentrations typically reported for nanowire devices indicate that when Schottky barrier transport is present, it occurs in the thermionic field emission regime with a substantial but not exclusive tunneling component. Analysis by thermionic field emission is difficult due to its multivariate nature. In recent work, we developed a mathematical stability approach that greatly simplified the evaluation of the multivariate thermionic field emission parameters. This is a general method with potentially wide applicability, requiring only the effective mass m* and relative dielectric constant εr for a given semiconductor as inputs. In the present work, we investigate the influence of the materials properties effective mass m* and relative dielectric constant εr on stability for a range of real and simulated semiconductor nanowires. A further investigation of temperature sensitivity and regime trends is presented.

Photoswitchable polymeric materials comprise moieties that undergo light-induced chemical reactions or conformational alteration. The reversibility of photo-responsive molecular switches has an influence on material functions observed on the macroscopic level such as reversibility of shape switching, especially with regard to the number of cycles. Cinnamylidene acetic acid (CAA) has received attention due to its reversible dimerization by [2+2] cycloaddition reactions. In the present study, possible side-reactions during photo-scission of the CAA dimers as netpoints in poly(ε-caprolactone) based materials were studied by fluorescence spectroscopy, HPLC and 1H,1H-COSY. Liberation of fluorescent fragments, which have their origin in the various dimer structures, could only be found in small amounts, while a non-identified species seems to be generated during dimerization and photo-scission. The results furthermore suggest that CAA-based switches in PCL-networks do not provide full reversibility of netpoint formation under the examined conditions, due to non-selective side-reactions, which could lead to an attenuation of the macroscopic effect in multiple photo-cycles. In perspective, the design of CAA derivatives with enhanced photo-reversibility should be targeted.

The formation frequency of habit plane variant (HPV) clusters in Ni-25Pd-50Ti shape memory alloy was analyzed using electron backscattering diffraction (EBSD) on the basis of the geometrically nonlinear theory of martensite. Two types of cluster, diamond and wedge, were most commonly observed. The ratio of the formation frequency of the diamond to wedge clusters was approximately 1 : 3, whereas the rotation to keep the kinematic compatibility (KC) condition, θ *, was 3.9° and 0.0032°, respectively. The ratio of the formation frequency is quantified by the value of θ * which is an indicator of the incompatibility of the cluster. The origin of the diamond cluster is discussed based on the degree of incompatibility.

We succeeded in photovoltaic power generation of p-i-n solar cells utilizing epitaxial ZnInON film with a wide band gap of 3.1 eV as the intrinsic layer, suitable for a top cell of tandem solar cells. The solar cell shows a high open circuit voltage (Voc) of 1.68 V under solar simulator light irradiation of 3.2 mW/cm2. The solar cell performance becomes worse under 100 mW/cm2, which is mainly attributed to the leakage current caused by crystal defects and grain boundaries. X-ray diffraction analysis reveals that the ZnInON film has rather large tilt and twist angles and a high dislocation density of 7.62×1010 cm-2. Such low crystallinity is a bottleneck for high performance of the solar cells. Our results demonstrate a potential of epitaxial ZnInON films as an intrinsic layer of wide band gap p-i-n solar cells with a high Voc.

Contributions of electronic (or ligand) and geometric (or ensemble) effects on the AuM bimetallic nano-catalyst were elucidated by using a simple aerobic oxidation of 1-phenylethanol to acetophenone on the basis of difference in the ionization energy values (Ei) between Au and M elements. The poly(N-vinylpyrrolidone) (PVP)-protected Au60M40 bimetallic NPs (M = Ag, Cu, Pd, Pt and Ir) were prepared with a polyol reduction method, and stabilized onto the solid base hydrotalcite support affording the Au60M40-PVP/HT catalysts. The yields for acetophenone were observed as the following order; Au60Pd40-PVP/HT (>99%) >> Au60Ag40-PVP/HT (17.4%) > Au60Cu40-PVP/HT (13.8%) > Au60Pt40-PVP/HT (7.1%) > Au60Ir40-PVP/HT (5.5%), at 343 K for 6 h. Differences in the Ei between Au and M (EiAu-EiM) indicted that the yields over the Ag, Cu, Pt, and Ir incorporated Au catalysts were well-understood on the ligand effects theory, though geometric factors such as differences in nanostructure around Au atom in Au60M40 NPs on HT should be further considered as other contributed factors. The significant activity on Au60Pd40-PVP/HT was studied in terms of the electron density of Pd atoms. It was observed that the Pd 4d density was varied by the amount of Au loading. According to these observations combined with our previous studies, we suggest that the advantages in AuPd bimetallic catalyst are not only in the ligand effect serving negatively-charged Au but also the ensemble effect of neighbor Pd, and they synergistically contribute to the novel activity for aerobic alcohol oxidation over AuPd catalyst.

In the present work, the stress relaxation method was employed to determine the influence of B addition on the kinetics of strain-induced precipitation and its interaction with the static austenite recrystallization. For this purpose, the behavior of two low carbon advanced ultra-high strength steels was analyzed during stress relaxation tests at different temperatures and constant pre-strain rate. The precipitation start (Ps) and finish (Pf) times were determined from the relaxation curves and then the corresponding precipitation-time-temperature diagrams were constructed for each steel. Transmission Electron Microscopy was used to determine the chemical nature and evolution of precipitation. In general, the results show that the addition of B retards the austenite recrystallization, tends to accelerate the precipitation kinetics of carbonitrides and leads to a finer and denser distribution of precipitates. These results are discussed in terms of the driving force for the nucleation of precipitation, which in turn is controlled by the degree of supersaturation of microalloying element and as a function of B segregation and B-vacancy complexes to dislocations and grain boundaries.