Alginate based microparticle drug delivery systems were prepared for the sustained release of antitumor drugs. Two drugs, cyclophosphane and 5-fluorouracil, were encapsulated into the microparticles. The drug loaded microparticles were fabricated using a very convenient method under very mild conditions by the gelation of alginate with calcium cation. Modified microparticles were obtained by syringed dropwise a solution of drugs in sodium alginate into chitosan solution in calcium chloride. The effect of polymers concentration and the drug loading (1.0, 5.0 and 10%) on the release profile of drugs were investigated. The amount of drug release was much higher initially (approximately 25%), followed by a constant slow release profile. All the release data show the typical pattern for a matrix controlled mechanism. The cumulative amount of drug released from alginate gels was linearly related to the square root of the time and the release rate decreased this time. The process is controlled by the diffusion of antitumor drugs through the chitosan coating. Scanning electron microscopy (SEM) and particle size analysis revealed differences between the formulations as to their appearance and size distribution. The experiments for anticancer action of alginate microparticles were determined at 120 inbreeded white rats (females, weight 120-125 g, age 2-3 month) infected by malignant Rhabdomyoma strain at the dose of 10 000 cells. Medical-biological tests show that the duration of anticancer activity for the drug-containing alginate microparticles increases at 5-8 times in comparison of free drugs. Such systems may have potential for controlled delivery of antitumor drugs for the treatment of eye cancer

Dimensional nanocomposites of PbTe with varying carrier concentrations were prepared from undoped and Ag doped PbTe nanocrystals synthesized utilizing an alkaline aqueous solution-phase reaction. The nanocrystals were densified by Spark Plasma Sintering (SPS) for room temperature resistivity, Hall, Seebeck coefficient, and temperature dependent thermal conductivity measurements. The nanocomposites show an enhancement in the thermoelectric properties compared to bulk PbTe with similar carrier concentrations, thus demonstrating a promising approach for enhanced thermoelectric performance.

Incorporation of an electron reflector is a proposed strategy to improve the open-circuit voltage of CdTe thin-film solar cells. An electron reflector is basically a conduction-band barrier at the back surface, which can reduce the recombination resulting from the electron flow to the back surface. It should be particularly beneficial for cells with thicknesses below two microns when the CdTe absorber layer is fully depleted at its typical carrier density, because back-surface recombination is a primary limitation to the performance of fully depleted cells. Cells with thickness below two microns can also benefit from optical reflection at the back interface.One-dimension numerical simulation is used to investigate the electron reflector strategy and optical back reflection for thin CdTe cells. Theoretically, about a 200-mV increase in voltage and 3% in efficiency are achievable for a thin CdTe solar cell with 2×1014-cm-3 hole density, 1-ns lifetime, and a 0.2-eV electron reflector barrier. Furthermore, with the electron reflector, good CdTe cell performance at thicknesses as thin as 0.4 μm should be possible.

Ferroelectric Bi1.1Fe0.9Co0.1O3 (BFCO) thin films were prepared on Pt/TiO2/SiO2/Si substrates by chemical solution deposition method using rapid thermal annealing (RTA). The thickness of all BFCO thin films is about 100 nm. Although the BFCO prepared at 545°C has a large value of difference of polarization at zero field, 88 C/cm2, the P-E hysteresis loop of the BFCO thin film prepared at 520°C looks like more saturated and shows 47 C/cm2 of difference of polarization at zero field in the applied electric field of 2 MV/cm. The leakage current of the BFCO film annealed at 520°C, is about 2 × 10-2 A/cm2 at room temperature (RT). Moreover, it is also shown that the saturated possibility of P-E hysteresis loops and in 2 MV/cm their apparent difference of polarization at zero field depend on not only the leakage current but also scanning frequency used to measure BFCO thin films. Accordingly, the P-E hysteresis loops of BFCO thin films prepared from 520°C to 545°C seem to be saturated at high frequency from 10 KHz to 20 KHz when these samples are measured at RT.

The pipelines are the main transport and distribution system of production in the oil industry, which are subject to environmental and operational conditions which are not favorable for the operation of the pipelines and sometimes represent the risk of accidents and high economic losses. The evolution of risk begins with a systematic search of possible threats to the integrity of the pipeline. The identification of potential threats should not be limited to known risk categories reviewed, but must complete the steps to find new and unique expressions of risk and the study of particular cases. Thus, the importance of a comprehensive risk assessment of the transmission pipeline is crucial. In this paper an integrity assessment for corrosion damages in pipelines was developed through a methodology based on risk analysis to estimate the propagation rate on the time, the size, location and number of damages. To perform this study a data obtained from smart pig runs and an artificial neural network (ANN) model with retro propagation was used. From the data obtained from launching smart pigs on the pipeline it was carried out the training of the neural network, later on it was applied the network previously trained to get the predictions of damages on the pipeline, considering that pipeline did not have any maintenance.

We have developed high efficiency large area a-Si:H and a-SiGe:H multi-junction solar cells using a Modified Very High Frequency (MVHF) glow discharge process. We conducted a comparative study for different cell structures, and compared the initial and stable performance and light-induced degradation of solar cells made using MVHF and RF techniques. Besides high efficiency, the MVHF cells also demonstrate superior light stability, showing <10% degradation after 1000 hour of one-sun light soaking at 50 °C. We also studied light-induced defect level and hydrogen evolution characteristics of MVHF deposited a-SiGe:H films and compared them with the RF deposited films.

The Boeing Company has developed a unique nanotechnology for antireflective coatings that can perform at near grazing angles (∼80°), in the long wave infrared (LWIR). This technology has been validated through mathematical modeling and the fabrication and testing of small scale components. The coatings were designed to perform best at 10 micron wavelengths, and moderately well over the 8 to 12 micron region. The technology is based upon a circuit analog sheet (capacitive) buried within a dielectric, to produce a reflection that adds out of phase with respect to the face sheet reflection. Since the TE component of the reflection is highest near grazing, the sheet is designed to primarily affect that polarization (low impedance) while leaving the TM wave unaffected (high impedance).

When desired, in order to improve the TM transmission as well as TE, two layers are used at different depths. This dual-layer approach has also been modeled (in closed form), fabricated and tested. Also, explored in this paper, are the impacts of a design that works well azimuthally at grazing angles.

Until recently, the above solution was limited to RF frequencies, but with advances in fabrication it has become possible to fabricate very small nanostructures that operate in LWIR using traditional thin-film vacuum deposition techniques. It is envisioned that eventually such a concept could be used in the visual regime via self assembly.

Photoelectrochemical (PEC) hydrogen production, using sunlight to split water, is an important enabling technology for a future “Green” economy which will rely, in part, on hydrogen as an energy currency. The traditional semiconductor-based PEC material systems studied to date, however, have been unable to meet all the performance, durability and cost requirements for practical hydrogen production. Technology-enabling breakthroughs are needed in the development of new, advanced materials systems, and toward this end, the U.S. Department of Energy’s Working Group on PEC Hydrogen Production is bringing together experts in analysis, theory, synthesis and characterization from the academic, industry and national-laboratory research sectors. Key Working Group activities, as described in this paper, include performing techno-economic analyses of large-scale PEC production systems and establishing standardized testing and screening protocols for candidate PEC materials systems. In addition, a number of Working Group “Task Forces” are focused on advancing critical PEC materials theory, synthesis and characterization capabilities for application in the research and development of broad-ranging materials systems of promise, including complex metal-oxide and -nitride compounds, amorphous silicon alloys, III-V semiconductors and the copper chalcopyrites. The current status of Working Group activities and progress is summarized.

A key process in a successful treatment of patients with a great variety of musculoskeletal implants requires a fast, reliable and consistent osseointegration. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role.

Different surface modification techniques to improve osseointegration have been proposed and tested to date, but most focus on microscale features, and few control surface modifications at nanoscale. On the other hand, ion implantation modifies the outermost surface properties in relation to the nanotopography, chemical and physical characteristics at nanoscale. The meta-stable surface that results from the treatment, affects the adsorption of bio-molecules in the very first stages of the implant placement, and thus the signaling pathway that promotes the differentiation and apposition of osteoblast cells.

This study aimed at assessing the performance, in terms of osseointegration levels and speed, of ion implanted titanium made implants. The study included several in vitro and in vivo tests. The latter, comprised different insertion periods and both experimental and commercial implants as comparative surfaces. The final stage of the study included clinical trials in human patients.

In each and every case, bone integration improvement of tested materials/implants was achieved for the CO ion implanted samples. Furthermore, contact osteogenesis was observed in the ion implanted samples, unlike the Ti control samples, where only distance osteogenesis occurred, being this potentially one of the reasons for their faster healing and osseointegration process.

Finally, the use of ion implantation as a surface modification tool that allows for evaluating the effects of nanotopography and composition changes independently is presented.

Haynes™ HR-120™ alloy is a solid-solution-strengthened heat resistant alloy. The main characteristics of this alloy are strength at elevated temperature combined with resistance to carburizing and sulfidizing environments. Typical solution heat treatment for this alloy is usually performed above 1100°C. Solution heat treatment promotes non-desired precipitates to dissolve and, if deformation parameters are adequate, re-crystallization after forging procedures. It is reported that the solution temperature can also promote non-controlled grain coarsening. This investigation summarizes results on the effect of solution heat treatment on the microstructure of forgings when it is performed at 1000°C, 1050°C and above 1100°C. The experimental conditions resemble industrial environments. The obtained results include the alloy microstructural evolution by optical microscopy and Scanning Electron Microscopy (SEM) and the effect of these heat treatments on mechanical properties such as tensile, hardness and stress-rupture properties.

With characteristic time constants for polymer dynamics, namely τs (the segment fluctuation time), τe (the entanglement time), and τR (the longest Rouse relaxation time), the time scales of particular interest (i) t<τs, (ii) τs<t<τe, and (iii) τe<t<τR will be discussed and compared with experimental data. These ranges correspond to the chain-mode length scales (i) l<b, (ii) b<l<d2/b, and (iii) d2/b<l<L, where b is the statistical segment length, d is the dimension of constraints by entanglements and/or confinement, and L is the chain contour length. Based on Langevin-type equations-of-motion coarse-grained predictions for the mean-squared segment displacement and the spin-lattice relaxation dispersion will be outlined for the scenarios “freely-draining”, “entangled”, and “confined”. In the discussion we will juxtapose “local” versus “global” dynamics on the one hand, and “bulk” versus “confined” systems on the other.

The major part of groundwater contaminants strongly interact with soils and aquifer rocks. Therefore sorption processes on porous matrix are of utmost importance in the frame of the nuclear waste disposal. The objectives of this study were to evaluate sorption uptake by silica sand of some safety-relevant metal ions such as Cs+, Sr2+, Cu2+, Ni2+ and to investigate the existence of competitive sorption processes between these ions. To this aim, kinetic and equilibrium, mono-component and multi-component, batch experiments were carried out in order to study: i) the influence of metal concentration, pH and contact time, on sorption onto silica sand of the above ions in aqueous solution, and ii) the presence of competition phenomena. Sorption data were well fitted by Langmuir and Freundlich models. Multi-component tests show that the uptake of each ion is reduced in presence of other ions in solution with respect to mono-component batch tests results and that competition between species appears influenced by the equilibrium times of the single species in solution and by pH.

The recent reports on giant piezoresistance effect in highly resistive silicon nanowires (SiNWs) have offer greater sensitivity in stress measurements. Despite enhanced sensitivity, the piezoresistance of highly conductive silicon are preferred as they are less prone to thermal noises and hence better accuracy. Here we report a thermal induced buckle micro-bridge technique to accurately characterize the temperature dependent piezoresistivity effect in SiNWs. Phosphorus doped <110> SiNWs with 50 nm width, 95 nm thickness and 100 μm length were encapsulated within SiO2 micro-bridges. The electrical measurement of both reference SiNWs and SiNWs at micro-bridges was carried out, followed by the optical profiling of the micro-bridges with embedded SiNWs. N-type SiNWs with doping of 1×1020 ion/cm3 exhibit a strong dependence on temperature with a piezoresistive coefficient that decreases by 22.5 % between 25 oC to 60 oC; whereas its bulk counterpart is independent of temperature across this range. The results demonstrated that thermal noises may be more detrimental to nano-scale electromechanical sensors than its bulk counterparts.

The Auger effect is one of the fastest recombination mechanisms in narrow band gap semiconductors at high carrier concentration. This regime is of great interest for high efficiency hot carrier solar cells application and is also involed in many optical devices. Therefore, the knowledge of this limitting process is required for the determination of carrier lifetime useful to accurate solar cell efficiency calculations. For the first time, we present a carrier lifetime study versus carrier concentration in InGaAs based on a Monte Carlo model where the Auger effect is included as a relaxation mecanism.

When clutch boards are fabricated as friction sheets in automatic transmission of motorcars, their useless fragments are disposed of. In this study, an effective reuse of their waste clutch boards will be proposed. Clutch boards are composed of diatomaceous earth, carbon powder/fiber and phenol resin. Excess carbon in carbonized clutch boards was reacted with SiO formed from Si and SiO2 at 1500 °C in Ar to produce porous SiC sheets (79% porosity). High temperature treatment at 1700-1900 °C in vacuum made it possible to control the pore size of SiC sheets, having a main pore diameter range of 10 to 20 μm.

SiC sheets with porosity (79% to <60%) were also fabricated by heating carbonized/impregnated sheets with phenol resin in SiO gas at 1500 °C. SiC sheets obtained by the repeated cycle of impregnation/decomposition of resin heating at 1700 °C gave a tensile strength of 19 MPa.

When Aluminum-tri-sec-butoxide (ASB) solution was impregnated into SiC sheets oxidized at 1000-1200 °C in air and heated at 1400-1500 °C in Ar, SiC-mullite composite sheets with porosity (77%) were produced.

Diatoms are unicellular eukaryotic algae found in fresh and marine water. Each cell is surrounded by an outer shell called a frustule that is composed of highly structured amorphous silica. Diatoms are able to transform silicic acid into these sturdy intricate structures at ambient temperatures and pressures, whereas the chemical synthesis of silica-based materials typically requires extremes of temperature and pH. Cationic polypeptides, termed silica affinity proteins (or silaffins) recently identified from dissolved frustules of specific species of diatoms are clearly involved and have been shown to initiate the formation of silica in solution. The relationship between the local environment of catalytic sites on these peptides, which can be influenced by the amino acid sequence and the extent of aggregation, and the observed structure of the silica is not understood. Moreover, the activity of these peptides in promoting silicification at lipid membranes has not yet been clarified. In this work we developed a model system to address some of these questions. We studied peptide adsorption to Langmuir monolayers and subsequent silicification using X-ray reflectivity and grazing incidence X-ray diffraction. The results demonstrate the lipid affinity of the parent sequences of several silaffin peptides. Further, the results show that the membrane-bound peptides promote the formation of interfacial nanoscale layers of amorphous silica at the lipid-water interface that vary in structure according to the peptide sequence.

College undergraduate and high school teacher internships are significant factors in materials science education. Traditionally, NSF-supported internships are done in academia. The NSF-supported academic/industrial internship programs involving Stanford University, San Jose University and the IBM Almaden Research Center extend the impact by the inclusion of an industrial research component. Internships through San Jose State University have existed since 1994 under a variety of NSF grants, most recently with NSF-REU support for undergraduate internships.Internships through Stanford university have existed since 1995 through an NSF Materials Research Science and Engineering Center, the “Center for Polymer Interfaces and Macromolecular Interfaces” (CPIMA).In these programs, the interns become members of an existing research group for 10 weeks and have their own project under a mentor. The interns attend a weekly seminar series on industrial research frontiers, a career day, a Graduate Record Examination workshop, a graduate school workshop, and tours of industrial research labs. Every participant presents a poster at an internal technical meeting at IBM at the end of the summer. For the industrial internships at IBM, the research is publishable but closely related to a technical area important to IBM. While the undergraduate and teacher internship programs are the major components of educational outreach of CPIMA, many other projects have been pursued, including public science, programs with local high schools, and science outreach to local community colleges. Dr. Marni Goldman was the Director of Educational Outreach for CPIMA from 2000 until her death in 2007, and she started many of the educational projects and programs. She was especially interested in diversity and initiated an internship program for students who are disabled. The programs will be reviewed and her contributions emphasized.

Several purification and processing techniques for laser-produced single wall carbon nanotube (SWCNT) soot were investigated and the resulting changes in the mechanical properties were characterized. SWCNT ribbons had non-nanotube carbonaceous content modified via thermal oxidation and the relationship between oxidation parameters and mechanical strength studied. SWCNT/Polyamide composites were developed and exhibited improved toughness, tensile strength and elongation before break. The composite material is observed to have a greater tensile strength than either the baseline paper or the added nylon.

We report a new integration approach to produce arrays of ZnO microcrystals for optoelectronic and photovoltaic applications. Demonstrated applications are n-ZnO/p-GaN heterojunction LEDs and photovoltaic cells. The integration process uses an oxygen plasma treatment in combination with a photoresist pattern on Magnesium doped GaN substrates to define a narrow sub-100nm width nucleation region. ZnO is synthesized in the defined areas by a hydrothermal technique using zinc acetate and hexamethylenetetramine precursors. Nucleation is followed by lateral epitaxial overgrowth producing single crystal disks of ZnO. The process provides control over the dimension and location of the ZnO crystals. The quality of the patterned ZnO is high; the commonly observed defect related emission in the electroluminescence spectra is suppressed and a single near-band-edge UV peak is observed. Transfer printing of the ZnO microcrystals onto a flexible substrate is also demonstrated in the context of transparent flexible electronics.

Cyclodextrin (CD) has been studied intensively due to its ability to form inclusion complexes with a variety of guest molecules in the solid state. A few studies have paid attention to the use of CD to facilitate the synthesis of inorganic nanoparticles. In this work the synthesis of magnetite (M) is made in the presence of CD. The particle size of the inorganic material is controlled by the presence of CD, in which spherical particles of few nanometers are grown. The synthesis of Fe3O4 (M) in the presence of α-cyclodextrin (α-CD) and β-cyclodextrin (βCD) is described. The formation of an M-CD complex is studied in both cases by Fourier transform infrared spectroscopy (FT-IR) in order to elucidate the chemical bonding of the complex. The morphology and size of the particles are determined by Field Emission Scanning Electron Microscopy (FESEM) and software. X-ray diffraction (XRD) is used to confirm the formation of magnetite.