bluuebunny/crossref_metadata_2025_split huggingface dataset:
The status of Ghanaian community health workers’ supervision and service delivery: descriptive analyses from the 2017 Performance Monitoring and Accountability 2020 survey
Authors: Schwarz Dan , Kim June-Ho , Ratcliffe Hannah , Bell Griffith , Awoonor-Williams John Koku , Nimako Belinda , Otupiri Easmon , Lipsitz Stuart , Hirschhorn Lisa , Bitton Asaf 
Published: June 2019

Introduction: Community-based services are a critical component of high-quality primary healthcare. Ghana formally launched the National Community Health Worker (CHW) program in 2014, to augment the pre-existing Community-based Health Planning and Services (CHPS). To date, however, there is scant data about the program’s implementation. We describe the current supervision and service delivery status of CHWs throughout the country. Methods: Data were collected regarding CHW supervision and service delivery during the 2017 round of the Performance Monitoring and Accountability 2020 survey. Descriptive analyses were performed by facility type, supervisor type, service delivery type, and regional distribution. Results: Over 80% of CHWs had at least monthly supervision interactions, but there was variability in the frequency of interactions. Frequency of supervision interactions did not vary by facility or supervisor type. The types of services delivered by CHWs varied greatly by facility type and region. Community mobilization, health education, and outreach for loss-to-follow-up were delivered by over three quarters of CHWs, while mental health counseling and postnatal care are provided by fewer than one third of CHWs. The Western region and Greater Accra had especially low rates of CHW service provision. Non-communicable disease treatment, which is not included in the national guidelines, was reportedly provided by some CHWs in nine out of ten regions. Conclusions: Overall, this study demonstrates variability in supervision frequency and CHW activities. A high proportion of CHWs already meet the expected frequency of supervision. Meanwhile, there are substantial differences by region of CHW service provision, which requires further research, particularly on novel CHW services such as non-communicable disease treatment. While there are important limitations to these data, these findings can be instructive for Ghanaian policymakers and implementers to target improvement initiatives for community-based services.
Fatigue and Static Properties of Built-up Friction Stir Welded Ti-6Al-4V I-Beams
Authors: Sharma Rahul , Fick Damon R. , West Michael K. , Jasthi Bharat K. 
Published: June 2019

Abstract
Modern aircraft systems use high-strength alloys, such as Ti-6Al-4V (Ti-6-4), for their components. The advantage of using Ti-6-4 is its high corrosion resistance and low weight to strength ratio when compared with other metals. The downside of using titanium is its high cost and lead time associated with procurement in addition to the material wastage that occurs with machining different cross-sectional geometries. Built-up titanium beams fabricated using friction stir welding (FSW) and readily available titanium plates may be a viable alternative that reduces these expenses. This study investigates the fatigue and static strengths of built-up titanium I-beams using FSW and 7-mm-thick Ti-6-4 plate material and compares the results with strengths of representative coupon specimens. Coupons in the transverse and longitudinal directions of the FSW were evaluated for both polished and as-welded FSW surfaces. The results of the investigation showed that the static flexural strength of the built-up I-beam reached 57 % of the yield strength of the Ti-6-4 plate material. The fatigue strengths of the two I-beams tested reached 87 and 63 % of comparable coupon-level specimens with as-welded and polished finishes, respectively. Failures in these beams initiated at discontinuities in the welded fillet region, which suggests that strength and fatigue performance of built-up titanium I-beams can be improved through more consistent FSW methods for Ti-6-4 plate materials.
Synthesis and Electrochemical Performance of SnO2/Graphene Hybrid Anode for Lithium Ion Batteries
Authors: Lin Chia-Yi , Hsieh Chien-Te , Juang Ruey-Shin 
Published: June 2019

ABSTRACTAn efficient microwave-assisted polyol (MP) approach is report to prepare SnO2/graphene hybrid as an anode material for lithium ion batteries. The key factor to this MP method is to start with uniform graphene oxide (GO) suspension, in which a large amount of surface oxygenate groups ensures homogeneous distribution of the SnO2 nanoparticles onto the GO sheets under the microwave irradiation. The period for the microwave heating only takes 10 min. The obtained SnO2/graphene hybrid anode possesses a reversible capacity of 967 mAh g-1 at 0.1 C and a high Coulombic efficiency of 80.5% at the first cycle. The cycling performance and the rate capability of the hybrid anode are enhanced in comparison with that of the bare graphene anode. This improvement of electrochemical performance can be attributed to the formation of a 3-dimensional framework. Accordingly, this study provides an economical MP route for the fabrication of SnO2/graphene hybrid as an anode material for high-performance Li-ion batteries.
Materials Engineering with a Social Context: A course on Materials, Ethics, & Society
Authors: Chen Katherine C. 
Published: June 2019

ABSTRACTA sophomore level Materials Engineering course entitled, “Materials, Ethics, & Society” at Cal Poly analyzes the interactions between technology and society, and emphasizes the communication of societal and ethical impacts of technology to diverse audiences. Students study materials in a historical context, not only to highlight specific materials science concepts, but also to explore societal-technology connections. Starting from the Stone Age, advances in civilizations have come about through discoveries and new uses of materials. World geography, history, and culture become intertwined with the casting of metals, alloy development, ceramics, and phase diagrams. Students highlight the social relevancy of materials throughout history, and seek parallel themes in today’s world. While learning about the development of the atomic bomb, students also examine the ethical dilemmas of the scientists and the current NSPE Code of Ethics for Engineers. In addition, the role of the engineering profession is examined with the NAE Engineering Grand Challenges and current news items. Students investigate how materials engineering can help society through examples of appropriate technology solutions, such as designing porosity in ceramics for water filters and food storage pots. Students develop their analytical and communication skills by discussing C.P. Snow’s “two cultures” and debating a rationale for scientific literacy. Students are also trained in informal science learning in preparation for NanoDays with young and diverse audiences. At the same time, they learn about nano-scale science and technology principles, and the associated societal and ethical implications. The course culminates with student-created videos for the general public that highlight a material or technology of importance to society and integrates the material science with ethical, environmental, and societal dimensions.
Math and Science Education Module for Introducing Nanotechnology, Light and Energy for Middle School Classrooms
Authors: Boykin Karen , Pan Shanlin , Goldston Dee , Allison Elizabeth 
Published: June 2019

ABSTRACTThe introduction of nanotechnology in early classroom pedagogy is becoming a high priority in education. However, the concepts of nanotechnology can be difficult to conceptualize due to the esoteric nature of the subject. Inquiry-based nanotechnology modules are one way to help visualize nanomaterials to deliver the concepts of nanotechnology. We present the implementation and effectiveness of a newly developed module tying existing light and energy curriculum in middle school to nanoparticles, introducing the concept of a photocatalyst and energy. The module is part of a five year teacher professional development program in the Alabama Black Belt through a Math Science Partnership award from NSF (0832129) to increase students’ interests at the middle school level for pursuing continued math and science education and creative research activities in the future. Students impacted by the program are from low income rural communities where it is critical in preparing the next generation scientists and engineers for our nation’s future energy challenges.
Plasmonic Light Trapping in Amorphous Si Solar Cells Using Periodic Ag Nanodisk Structures
Authors: Mizuno Hidenori , Sai Hitoshi , Matsubara Koji , Kondo Michio 
Published: June 2019

ABSTRACTThis paper describes light trapping in superstrate-type amorphous Si solar cells incorporated with Ag nanostructures (nanodisks) fabricated by a transfer-printing approach. The changes in external quantum efficiency (EQE) and current-voltage characteristics were investigated by changing the position and size (thickness) of the Ag nanodisks in the cells fabricated on flat superstrates. It was confirmed that the optimized Ag nanodisk-configuration led to the enhanced EQE (20%) in the 600-800 nm wavelength range, and the enhanced EQE led to the improved overall conversion efficiency (7.5%) compared to the cell without Ag nanodisks (7.2%). However, the integration of the optimized Ag nanodisk-configuration with the cells fabricated on textured superstrates did not result in the enhanced EQE and conversion efficiency, suggesting further optical designs are necessary to exploit both texture- and plasmon-mediated light trapping effects.
Investigating the surface changes of silicon in vitro within physiological environments for neurological application
Authors: Nezafati Maysam , Saddow Stephen E. , Frewin Christopher L. 
Published: June 2019

ABSTRACTSilicon has been used as one of the primary substrates for micro-machined intra-cortical neural implants (INI). The presence of various ions in the extracellular environment combined with cellular biological activity establishes a harsh, corrosive environment in the brain for INI, and as such, a long-term implant’s construction materials must be able to resist these environments. We have examined if environmental components could contribute to changes in the material, which in turn may be a contributing factor to the decreased long-term reliability in INI optimal neural recordings, which have prevented clinical use these devices for the last 4 decades. We tested silicon in artificial cerebrospinal fluid (ACSF), Dulbecco's modified eagle medium (DMEM), and H4 cells cultured within DMEM for 96 hours at 37°C as three various physiological environments to investigate the material degradation. We have observed that Si samples immersed in only DMEM and ACSF showed very minor surface alterations. However, Si samples cultured with H4 cells exhibited a large change in surface roughness from 0.24±0.04 nm to 4.85 nm. The scanning electron microscope (SEM) micrographs showed the presence of pyramid shaped pits. Further characterization with atomic force microscope (AFM) verified this result and quantified the severe changes in the surface roughness of these samples. At this initial stage of the investigation, we are endeavoring to identify the cause of these changes to the Si surface, but based on our observations, we believe that the increased corrosion could be result of chemical products released into the surrounding environment by the cells.
Effect of Microstructure on Phase Formation in Reaction of The Nb/Al Multilayer Thin Films
Authors: Barmak Katayun , Coffey Kevin R. , Rudman David A. , Foner Simon 
Published: June 2019

AbstractWe investigated the phase formation sequence in the reaction of multilayer thin films of Nb/Al with overall compositions of 25 and 33 at.% AI. We report novel phenomena which distinguish thin-film reactions unequivocally from those in bulk systems. For sufficiently thin layers composition and stability of product phases are found to deviate significantly from that predicted from the equilibrium phase diagram. We demonstrate that in the Nb/Al system the length scales below which such deviations occur is about 150 nm. We believe that these phenomena occur due to the importance of grain boundary diffusion and hence microstructure in these thin films.
Phase Transformations in Co/Nb and Co/Zr Multilayer Film Stacks.
Authors: Lin J. C. , Hoffman R. A. 
Published: June 2019

AbstractIon-beam mixing and isothermal annealing techniques were applied to induce phase transformations in Co/Nb and Co/Zr multilayer film stacks. Transmission electron microscopy(TEM) and x-ray diffraction(XRD) were used to characterize the microstructure of the films. Interfacial morphology and chemistry of the films were examined by Rutherford backscattering spectrometry(RBS) and cross-section transmission electron microscopy(XTEM). The formation of amorphous phases was found in both systems by either technique. A comparison of the phase transformation mechanisms induced by ion-beam mixing and isothermal annealing is given. The thermodynamic and kinetic factors controlling the phase formation and stability are discussed. For the isothermal annealing, the final stable configuration is predicted by equilibrium phase diagrams.
Changes in u(VI) SPeciation Upon Sorption onto Montmorillonite from Aqueous and Organic Solutions
Authors: Chisholm-Brause Catherine , Conradson Steven D. , Eller P. Gary , Morris David E. 
Published: June 2019

ABSTRACTThe speciation of UO22+ and UO22+/ TBP mixtures has been investigated in solution and intercalated with the reference smectite clay SAz-1 using x-ray absorption, Raman, andluminescence spectroscopies. Neither aquated UO22+ nor its TBP complex undergoes any detectable changes in uranium oxidation state on intercalation. Further, at the pH values employed in this work, there is no evidence for hydrolysis of the uranium species to generate dimeric or higher order uranium oligomers. However, we do find indications that the structures of the solution complexes are altered on intercalation, particularly for the UO22+TBP system and for more dilute UO22+/aqueous systems. In addition, several lines of evidence suggest that, at the loading levels used in this study, the uranyl species is interacting with two or more spectroscopically distinguishable sites on SAz-1.
Integrated, Dual-Function Remote Plasma-Enhanced Processing Applied to Low Damage SiO2 Etching and Removal of C-F Polymer Residues
Authors: Yasuda T. , Lucovsky G. 
Published: June 2019

ABSTRACTWe report a dual-function chamber integrating (a) remote RF plasma-enhanced etching of SiO2 layers on Si(100) surfaces with low energy, <100 eV, ion bombardment and (b) in-situ removal of polymeric C-F residues that are formed on the exposed Si surfaces. Using direct plasma excitation of He and downstream introduction of CF4, an SiO2 etch rate of ̃5 nm/min was obtained at a CF4 partial pressure as low as 0.25 mTorr. An exposure to atomic-H at a substrate temperature of 250°C was effective in removing polymeric residues from the Si surface, while an exposure to reactive O-species was less effective. We achieved a low-temperature, ̃300°C, homoepitaxial growth of Si on the Si(100) surface that was subjected to plasma etching followed by an exposure to atomic-H. The electrical damage of the processed Si surfaces was evaluated by a new technique, where a device-quality SiO2 film was deposited on this surface by remote PECVD and the C-V characteristics of the MOS structure were measured.
Bulk Restructuring of Amorphous Tungsten Trioxide Films Due to Hydration of the Film/Electrolyte Interface
Authors: Shiyanovskaya I. V. 
Published: June 2019

ABSTRACTThe influence of film/electrolyte interface on structure and electrochromic properties of amorphous WO3 (a-WO3) films has been studied using cyclic voltammetry, optical electrochemistry and vibrational spectroscopy.
Electrochemical Fabrication of the Nano-Wire Arrays: Template, Materials And Applications
Authors: Routkevitch Dmitri , Chan Jimmy , Davydov Dmitri , Avrutsky Ivan , Xu J. M. , Yacaman M. J. , Moskovits Martin 
Published: June 2019

ABSTRACTAnodic aluminum oxide (AAO) may be used as a template for electrochemically fabricating metal and semiconductor nano-wires. We assess the seminal factors involved in each step in this fabrication process with an aim at producing device-quality semiconductor nano-arrays. This includes an analysis of the electrochemical factors, the structural effects resulting from the templating, the crystallinity of the nano-wires, their anisotropy and their suitability for device applications.
Photonic Applications of Bipolaron Formation in Bis-(Diphenylamino)Diphenylpolyene
Authors: Ashworth K. , Reeves B. , Frost A. , Spangler C. 
Published: June 2019

ABSTRACTBis-(dialkylamino) and bis-(diphenylamino) substituted diphenylpolyenes have recently been shown to have exceptionally large two-photon cross-sections, and have also been used in optical power limiting (OPL) applications. Another potential mechanism for OPL in these materials involves the photogeneration of highly absorbing polaronic radical-cations or bipolaronic dications which can then function as highly absorbing reverse saturable absorbers (RSAs). The synthesis of series of these unique polyenes has been carried out, as well as studies of chemically induced bipolaron formation in solution. In order to actually be used in OPL devices, it is probable that these chromophores will need to be incorporated into polymer formulations, In this paper we describe three distinct ways that these chromophores can be incorporated in polymer structures: (1) as pendant groups attached to a PMMA backbone, (2) as formal repeat units in a copolymer, and (3) perhaps the most interesting, as surface attached functionalities in dendrimer formulations. The formation of bipolaron charge species in these polymers will be addressed.
Humidity-Induced Cohesion Effects in Granular Media
Authors: Fraysse Nathalie , Petit Luc 
Published: June 2019

ABSTRACTExperiments were performed under accurately-controlled humidity conditions in order to quantify effects induced by humidity on granular materials. Measurements of the maximal stability angle of a pile made of small glass beads are reported as a function of the relative vapor pressure in the cell, up to close to saturation. The comparison of the results obtained with fluids differing in their molecular interactions with glass, namely water and heptane, shows that the wetting properties of the interstitial liquid on the grains have a strong influence on the cohesion of the non-saturated granular medium. This suggests that gravimetric experiments which could indirectly give information on the size of the capillary bridges that form between grains should be useful to understand the close connection that exists, through interparticle forces, between microscopic properties such as wetting properties and surface roughness of the grains, and global-scale properties of the pile, as its stability and flowability.
Subsurface Damage Characterization of Hydrogen Ion Implanted Silicon Wafer with Uv/Millimeter-Wave Technique
Authors: Ogita Yoh-Ichiro , Kobayashi Ken-Ichi , Kurokawa Masaki , Kondo Hideyuki , Katoh Takeo 
Published: June 2019

ABSTRACTThe UV/mm-wave technique composed of ultraviolet photoexcitation and millimeter wave probe was examined with photoconductivity amplitude (PCA) to characterize the slight subsurface damage induced by implanting H2+ ion into the subsurface at sub micron depth of Si wafers. The identical samples were also characterized using pulse photoconductivity amplitude (PPCA) obtained by another technique which is specified by blue laser photoexcitation and microwave probe. PCA decreased with increase of ion dose, which coincided well with the result in PPCA. PPCA decreased with increase of implantation energy as 90 to 120 keV, but PCA increased at 120keV. Both PCA and PPCA well reflected the damage at sub micron depth. PCA reflected damage in shallower depth compared to PPCA.
Atomically-based Field Formulations for Coupled Problems of Composition and Mechanics
Authors: Garikipati Krishna , Bassman Lori C. 
Published: June 2019

AbstractPreliminary ideas are presented on developing coupled, continuum field formulations for composition and mechanics with applications to microelectronic materials. A thermodynamic basis is constructed, reflecting atomic-level transport mechanisms and the associated mechanics. Formal arguments lead to constitutive field relations, and specification of balance laws completes the coupled field description. Early numerical results are also presented.
Recent developments in sensitized mesoporous heterojunction solar cells
Authors: Krüger Jessica , Bach Udo , Plass Robert , Piccerelli Marco , Cevey Le , Grätzel Michael 
Published: June 2019

ABSTRACTThe performance of solid-state dye-sensitized solar cells based on spiro-MeOTAD (2,2'7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene) was considerably improved by decreasing charge recombination across the interface of the heterojunction. This was achieved by blending the hole conductor matrix with a combination of 4-tert-butylpyridine (tBP) and Li[CF3SO2]2N. Open circuit voltages (Uoc) over 900mV and short circuit currents (Isc) up to 5.1 mA were obtained, yielding an overall efficiency of 2.56 % at AM1.5 illumination. Further improvement of the device performance was observed when conducting stripes of silver were deposited onto the devices as charge collector. The beneficial effect however could be assigned to the contamination of the dye-sensitized TiO2 film with silver during the dyeing process.
Ab Initio Studies On Phase Behavior of Barium Titanate
Authors: Uludogan Mustafa , Cagin Tahir , Goddard William A. 
Published: June 2019

AbstractUsing DFT methods we have studied structure, equation of state, and phase behavior of BaTiO3. We have identified the pressure induced phase transformations from the rhombohedral to orthorhombic structure at ca. 5 GPa and from tetragonal phase to cubic phase at ca. 7.5 GPa.
Optimization of Thermal Processing and Chemistry in the Fabrication of a PZT Based Mems Power Generator
Authors: Olson B.W. , Skinner J.L. , Richards C.D. , Richards R.F. , Bahr D.F. 
Published: June 2019

AbstractThin films of lead zirconate titanate (PZT) are currently being used in a novel MEMS device to generate power. A piezoelectric stack consisting of platinum/PZT/gold is deposited by sputtering, spin coating, and subsequent heat treatments onto a thin silicon membrane, which is cyclically polarized by a flexing motion. The membrane must withstand strains between 0.1% and 0.5% for several billion cycles to provide a useful device. This study has examined the processing-structure-property relationships in developing the PZT film for use in this device. In the sol-gel deposition of PZT, pyrolysis and crystallization temperatures have been shown to alter both microstructure and properties of the piezoelectric film. The chemistry of the PZT film has also been tailored to increase piezoelectric output for this device. Ferroelectric properties are compared to the piezoelectric outputs, and fatigue behavior is measured on bulk silicon and on membranes.
The Orthorhombic Phase of CaSiO3 Perovskite
Authors: Magyari-Köpe Blanka , Vitos Levente , Grimvall Göran , Johansson Börje , Kollár János 
Published: June 2019

AbstractAb initio total energy calculations, combined with the global parametrization method of perovskite structures, are used to investigate the stability of cubic CaSiO3 against octahedral rotations. We propose an equilibrium crystal structure of orthorhombic Pbnm symmetry. The larger compressibility of the SiO6 octahedra relative to the CaO12 polyhedra is reflected in gradual reduction of the orthorhombic distortion with hydrostatic pressure.