bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Gamma Radiolysis on Waste Package Components
Authors: Lewis Michele A. , Reed Donald T. 
Published: June 2019

AbstractPreliminary short-term experiments to study the effect of gamma radiation on the waste package materials interactions in the environment of a nuclear waste repository in basalt were completed. Experimental parameters were similar to those expected during the saturated post- closure period of the repository, i.e., a temperature of 200°C and a hydrostatic pressure of ≤70 bar. The test components included various combinations of synthetic groundwater (GR4), low carbon steel coupons, CH4, basalt, and basalt/bentonite mixtures (packing). The tests were run in low carbon steel pressure vessels.It was found that gamma radiation at a dose rate of 104rad/hr for a duration of one and two months increased the H2 yield in all tests. Increases in the organic carbon yield, the sulfate ion concentration, and the corrosion rate of the coupon were observed in some of the tests. These latter results varied with the combination of waste package components included in the tests. Evidence for the quench effect was observed in tests which included basalt.
Radiation Damage and Its Annealing in Sodium Silica Glass
Authors: Mark T.D. , Ritter W. 
Published: June 2019

AbstractAnnealing of radiation damage in artificial sodium silica glass has been studied by absorption spectroscopy for different radiation sources (fission fragments produced by n,f reactions, alpha decays produced by n, α reactions, and 2 MeV electrons) as a function of annealing time and temperature. The annealing observed can be described best by a single exponential functionA(t) = a exp (− αt)with an Arrhenius type temperature dependence of the annealing coefficient αα(T) = α0 exp (− EA/kT)For the three different radiation sources similar activitation energies EA were deduced from the data. Possible annealing processes are discussed.
Tc Behavior in the Basalt-Synthetic Groundwater System as a Function of Temperature and Initial Oxygen Content
Authors: Wood M. I. , Ames L. L. , Mcgarrah J. E. 
Published: June 2019

AbstractExperiments have been completed in the basalt-Tc-doped groundwater sys- tem to quantify the mobility of Tc in the waste package and near field envion- ment in a repository located in basalt. The experiments were completed using a batch sorption technique in which 8 rushed basalt and Tc-doped groundwater were reacted at 85, 100, 125 and 150 °C for periods of time up to 118 days. The water to rock ratio was 10:1 ml/g. In another set of experiments, basalt crushed under anoxic conditions and Tc-doped groundwater were reacted at 85°C at different water to rock ratios (10:3, 20:3, 40:3 and 80:3 ml/g).The rate and percentage of Tc removed from solution increased with increasing temperature and decreasing water to rock ratio. Also, basalt crushed under anoxic conditions removed >87% of Tc from solution at 85°C in 7 days while no Tc was removed from solution with basalt crushed in air at the same temperature after 118 days. These results are consistent with the hypothesis that (1) ferrous iron in basalt phases preferentially consumes oxygen and will not reduce Tcuntil all free oxygen in the system is consumed. Once oxygen is consumed, reduction of Tc is quite rapid. These data indicate that the potential exists in a basalt hydrothermal environment to satisfactorily immobilize Tc. Reliable application of these data will depend on experimental and theoretical estimates of oxygen consumption with time in the waste package environment following repository closure, subsequent saturation and long term hydrothermal reactions.
Radiometric Dating of Ochoan (Permian) Evaporites, Wipp Site, Delaware Basin, New Mexico, Usa
Authors: Brookins Douglas G. , Lambert Steven J. 
Published: June 2019

AbstractWe have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant--a US DOE facility) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization, (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data, and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 ± 10 Ma, even when some sylvites yield lower K-Ar dates due to l1s of 40Ar*. K-Ar dates on leonites and kieserites are also low due to 40Ar* loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 ± 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 ± 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.
Spent Fuel as a Waste Form - Data Needs to Allow Long Term Performance Assessment Under Repository Disposal Conditions.
Authors: Oversby V. M. 
Published: June 2019

AbstractPerformance assessment calculations are required for high level waste repositories for a period of 10,000 years under NRC and EPA regulations. In addition, the Siting Guidelines (IOCFR960) require a comparison of sites following site characterization and prior to final site selection to be made over a 100,000 year period. In order to perform the required calculations, a detailed knowledge of the physical and chemical processes that affect waste form performance will be needed for each site. While bounding calculations might be sufficient to show compliance with the requirements of IOCFR60 and 40CFRI91, the site comparison for 100,000 years will need to be based on expected performance under site specific conditions. The only case where detailed knowledge of waste form characteristics in the repository would not be needed would be where radionuclide travel times to the accessible environment can be shown to exceed 100,000 years. This paper will review the factors that affect the release of radionuclides from spemt fuel under repository conditions, summarize our present state of knowledge, and suggest areas where more work is needed in order to support the performance assessment calculations.
Mechanical properties and size effect in nanometric W/Cu multilayers
Authors: Villain P. , Faurie D. , Renault P.-O. , Bourhis E. Le , Goudeau P. , Badawi K.-F. 
Published: June 2019

AbstractThe mechanixcal behavior of W/Cu multilayers with periods ranging from 24 down to 3 nm prepared by ion beam sputtering was analyzed using a method combining X-ray diffraction and tensile testing, and instrumented indentation. Cracks perpendicular to the tensile axis observed by optical microscopy were generated in the films under the largest applied tensile stresses. These cracks may appear in the multilayer while W layers are still in a compressive stress state. Elastic modulus and hardness values were extracted from nano-indentation data. Crack initiation and elastic constants were observed to depend on the period of these multilayers.
Improvement of the Elastic Modulus of Micromachined Structures using Carbon Nanotubes
Authors: Joshi Prasoon , Duarte Nicolás B. , Goyal Abhijat , Gupta Awnish , Tadigadapa Srinivas A. , Eklund Peter C. 
Published: June 2019

AbstractMicroelectromechanical flexural structures have been fabricated using sandwiched multi-layers consisting of bundled singled walled carbon nanotubes(SWNTs) incorporated into silicon nitride (Si3N4) films. The Si3N4-SWNT composite layer was patterned by reactive ion etching followed by release in XeF2 to create freestanding bridge structures. The mechanical stiffness of the micromechanical bridges was monitored via force-displacement (F-D) curves obtained using an Atomic Force Microscope (AFM). Inclusion of SWNTs resulted in an increase in the spring constant of the bridge by as much as 64%, with an average increase of 25%. In a second experiment, micromachined bridges fabricated using dissolved wafer process were coated with debundled SWNTs. The SWNTs suspended in N-methyl-2-pyrrolidinone (NMP) solvent were sprayed locally on each bridge using a piezoelectric print head. Resonance frequency measurements were done in vacuum (∼10-4 Torr) on the bridges after successive SWNT depositions. A 20% increase in the resonance frequency of the bridges was observed. The observed increase in stiffness in the first set of experiments as well as the observed increase in the frequency in the second set of experiments can be attributed to the high axial modulus of elasticity (∼1 TPa) of the carbon nanotubes.
Role of stress on the phase control and dielectric properties of (1-x) BiFeO3 - xBa0.5Sr0.5TiO3 solid solution thin films
Authors: Cho Chin Moo , Hong Hee Bum , Hong Kug Sun 
Published: June 2019

AbstractDielectric properties and structure of (1-x) BiFeO3 (BFO) - x Ba0.5Sr0.5TiO3 (BST) (x = 0 ∼1) solid solution thin films were investigated. All films were prepared at 600 oC on (111) oriented Pt / TiO2 / SiO2 / Si substrates by pulsed laser deposition (PLD) technique. Solid solution could be achieved in all composition ranges, evidenced by X-ray diffraction (XRD) and field emission scanning electric microscope (FE-SEM). The intermediate compositions (0.4 = x = 0.8) exhibited a distinct (111) oriented cubic perovskite structure, while rhombohedra symmetry was found in the x < 0.4 range. Dielectric constant and tunability of the (1-x) BFO – x BST films within this composition region (0.4 = x = 0.8) decreased from 1110 to 920 at 1 MHz, and increased from 28.34 % to 32.42 % at 200 kV/cm, respectively, while loss tangent remains constant. A systematic decrease in lattice parameter with BST addition reduced stress due to reduction of lattice parameter mismatch between film and the substrate. In that range, the improvement of the dielectric properties without a degradation of loss tangent is attributed to the presence of the stress relaxation, which was quantitatively confirmed by a surface profiler based on Stoney's equation.
Residual Stresses in TiO2 Anatase Thin Films Deposited on Glass, Sapphire and Si Substrates
Authors: Al-Homoudi Ibrahim A. , Zhang Linfeng , Georgiev D.G. , Naik R. , Naik V.M. , Rimai L. , Simon Ng K.Y. , Baird R.J. , Auner G.W. , Newaz G. 
Published: June 2019

AbstractAnatase-TiO2 films (thickness 100-1000 nm) were grown on glass, sapphire, and Si(100) substrates using pulsed dc-magnetron reactive sputtering. By measuring the curvature of substrates before and after the thin film deposition, the residual stresses were determined. These results clearly show that the bi-axial stresses are compressive type and decreases with the increasing film thickness. The Raman spectra of these films were measured with two different excitation wavelengths (514 and 785 nm) and the thickness dependent shifts of Eg phonon mode were studied. The dominant 144 cm-1 Eg mode in TiO2 anatase clearly shifts to a higher value by 0.45 to 17.4 cm-1 depending on the type of substrate and the thickness of the film. Maximum shift was seen for the films on glass substrate indicating a higher bi-axial compressive stress in agreement with the curvature measurements. The excitation wavelength dependent shift of Eg mode clearly shows that the bi-axial stress increases along the film depth, being larger at the film/substrate interface.
Stress Analysis of Strained Superlattices.
Authors: Peleshchak R. , Khlyap H. 
Published: June 2019

AbstractThe latest successful development of smart technologies, in particular, molecular-beam epitaxy technique and pulse-laser deposition method, made it possible to manufacture optoelectronic active elements based on semiconductor materials with sufficient mismatch of the lattice parameters. This problem is of special interest for preparing photosensitive devices with strained superlattices. The paper focuses on the analysis of charge carriers behavior in mechanically strained superlattices based on semiconductor materials from A2B6 and A4B6 (ZnSe, ZnTe and PbS) playing an important role in the optoelectronics design. Computational modeling is settled on the solution of one-dimensional Schroedinger equation.
Analysis of film residual stress on a of 4-point bend test for thin film adhesion
Authors: Roham Sassan , Hight Timothy 
Published: June 2019

AbstractThe four-point bend (4PB) test has emerged as a method of choice in semiconductor industry for obtaining bimaterial interface adhesion data. When measuring the interface adhesion using 4PB test, it is essential to obtain a crack through the interface of interest. The deposited films, however, posses intrinsic and extrinsic stresses which affect the ratio between energy release rates for interface cracking and crack penetration. Crack penetration and deflection at a bimaterial interface and the role of residual stress has been broadly studied before. However, the results are based on asymptotic analysis regarding interface between two semi-infinite half spaces, where the results do not directly account for boundary conditions and finite size effects of an actual test specimen. In this paper, we look at the role these residual stresses play on the competition between deflection and penetration energy release rates of a bimaterial interface and the extent of which the previous assumption of two semi-infinite media can be accepted.
Thermomechanical Behavior and Properties of Passivated Pvd and Ecd Cu Thin Films
Authors: Gregoire M. , Kordic S. , Gergaud P. , Thomas O. , Ignat M. 
Published: June 2019

AbstractThe thermomechanical behavior is investigated of SiCN-encapsulated blanket Physical Vapor Deposited (PVD) and Electrochemically Deposited (ECD) Cu films. At lower ECD Cu film thicknesses an anomalous shape and a tail of the stress-temperature curve are observed, which are not caused by impurities at the interfaces, but are correlated to highly textured microstructure. Repeated thermal cycling of up to 400 °C does not markedly change the texture of the films, but a significant texture change takes place with increasing ECD Cu thickness. Thermal cycling induces grain growth for thicker films only. Impurity content and distribution in the PVD films do not change due to cycling.
Elastic behavior of fibre-textured gold films by combining synchrotron X-ray diffraction and in-situ tensile testing
Authors: Faurie D. , Renault P.-O. , Bourhis E. Le , Goudeau P. 
Published: June 2019

AbstractThe elastic behavior of gold thin films deposited onto Kapton substrate has been studied using in-situ tensile tester in a four-circle goniometer at a synchrotron beam line (LURE facility, France). Knowing the stress tensor in the film, the strong {111} fibre texture was taken into account using the Crystallite Group Method (CGM). CGM strain analysis allows predicting a non linear relationship between strain and sin2 Ψ obtained for the thin films due to the strong anisotropy of gold. In contrast, the average of strains in longitudinal and transversal directions varies linearly with sin2 Ψ. The evolution of the slope of these curves as a function of the applied stresses in the film allowed determining the single-crystal elastic constant s44 of thin gold films.
Novel Single Frequency and Broadly Tunable Laser Sources Developed at Coherent Technologies Inc. for Remote Sensing Applications
Authors: Phillips Mark W. 
Published: June 2019

AbstractThis paper provides an overview of novel single frequency and broadly tunable laser technology being developed at Coherent Technologies, Inc. (CTI) for long-range remote sensing of hard targets and distributed targets from ground based and airborne platforms. In all these applications, the need for high beam quality and efficient high power operation is paramount. For many of the applications, it is also critical to control and measure frequency content of the emitted and collected light to a high degree of accuracy. For example, a sub-kHz linewidth is typically required for velocity and vibration imaging, and sub-MHz linewidth for some differential absorption lidar (DIAL) type measurements.
Laser And Nonlinear Optical Materials For Laser Remote Sensing
Authors: Barnes Norman P. 
Published: June 2019

AbstractNASA remote sensing missions involving laser systems and their economic impact are coutlined. Potential remote sensing missions include: green house gasses, tropospheric winds, ozone, water vapor, and ice cap thickness. Systems to perform these measurements use lanthanide series lasers and nonlinear devices including second harmonic generators and parametric oscillators. Demands these missions place on the laser and nonlinear optical materials are discussed from a materials point of view. Methods of designing new laser and nonlinear optical materials to meet these demands are presented.
Robust, Efficient, Optical-Damage-Resistant, 200 mJ Nanosecond Ultraviolet Light Source for Satellite-Based Lidar Applications
Authors: Armstrong Darrell J. , Smith Arlee V. 
Published: June 2019

AbstractConventional wisdom contends that high-energy nanosecond UV laser sources operate near the optical damage thresholds of their constituent materials. This notion is particularly true for nonlinear frequency converters like optical parametric oscillators, where poor beam quality combined with high intra-cavity fluence leads to catastrophic failure of crystals and optical coatings. The collective disappointment of many researchers supports this contention. However, we're challenging this frustrating paradigm by developing high-energy nanosecondUVsources that are efficient, mechanically robust, and most important, resistant to optical damage. Based on sound design principles developed through numerical modeling and rigorous laboratory testing, our sources generate 8-10 ns 190 mJ pulses at 320 nm with fluences≤ 1 J/cm2. Using the second harmonic of a Q-switched, injection-seeded Nd:YAGlaser as the pump source, we convert the near-IR Nd:YAG fundamental to UV with optical-to-optical efficiency exceeding 21%.
Two MOEMS Microphone Designs for Acoustic Sensing Applications
Authors: Avset Berit S. , Bakke Kari A. H. , Fismen Britta. G. , Johansen Ib-Rune , Rogne Henrik , Sagberg Håkon , Wang Dag T. 
Published: June 2019

AbstractTwo different micro-optical microphones are presented. The first is based on interferometric read-out of a deflecting membrane, based on the Fabry-Perot principle. The sensing device is produced in Silicon by combining standard CMOS and MEMS processing. This ensures that high accuracy alignment and low cost production can be obtained. Optical sensor elements with a ring structure are included on one of the Fabry-Perot surfaces whereas the other surface is an optically transparent membrane. Light from an uncollimated light source such as a semiconductor laser or a LED, will form a ring pattern when transmitted through the membrane.The other microphone principle presented is based on a diffractive lens. The structure has a metallic ring pattern separated from a reflecting membrane with an air gap. When the air gap is an odd number of quarter wavelengths of the impinging light, these surfaces form a binary phase diffractive lens. By placing a light source and a detector in the focal plane of the lens, the measured intensity will be highly sensitive to the position of the membrane. Similarly to the first microphone this device can be mass produced at low cost using micromachining techniques.Results from prototype devices will be presented, proving both principles and showing excellent properties compared to expensive commercially available condenser microphones.
Bone Health Improvement Protocol
Authors: Wool Nathan K. , Wilson Shannon , Chong Alexander C.M. , Dart Bradley R. 
Published: June 2019

Introduction. Metabolic bone disease is a malady that causessignificant morbidity and mortality to a patient who has sustaineda fragility fracture. There is currently no protocol toprevent secondary fragility fracture at our institution. The objectiveof this study was to create an appropriate protocol forimplementing clinical pathways for physicians to diagnose andtreat osteoporosis and fragility fractures by educating patients.
Methods. A multidisciplinary team created an appropriateprotocol that could be implemented in an inpatient setting.A thorough literature review was conducted to evaluatepotential barriers and efficacious methods of protocol design.
Results. A bone health improvement protocol was developed.Any patient over the age of 50 who sustains a fracture from lowenergy trauma, such as a fall from standing or less, should beconsidered to place into this protocol. These patients receivededucation on metabolic bone disease, a prescription for highdose vitamin D therapy, and laboratory testing to determinethe etiology of their metabolic bone disease. Continuity of careof these patients with their primary care provider was providedfor further management of their metabolic bone disease andevaluation of their disease after discharged from the hospital.
Conclusion. Comprehensive secondary prevention should consistof osteoporosis assessment and treatment together with afall risk assessment. With this protocol, secondary fragility fracturespotentially could be prevented. KS J Med 2017;10(3):62-66.
Assessing Medical Student’s Ability to Interpret Traumatic Injuries on Computed Tomography Before and After the Third Year Clerkships
Authors: Werth Brady , Nguyen Barbara , Ward Jeanette , Reyes Jared , Helmer Stephen D. , Nold Joseph , Brewer Nicholas , Haan James 
Published: June 2019

Introduction. Exposure to radiologic images during clinical rotationsmay improve students’ skill levels. This study aimed to quantifythe improvement in radiographic interpretation of life-threateningtraumatic injuries gained during third year clinical clerkships (MS-3).
Methods. We used a paired-sample prospective study design tocompare students’ accuracy in reading computed tomography (CT)images at the beginning of their third year clerkships (Phase I) andagain after completion of all of their third year clerkships (Phase II).Students were shown life-threatening injuries that included head,chest, abdomen, and pelvic injuries. Overall scores for Phase II werecompared with Phase I, as well as sub-scores for each anatomicalregion: head, chest, abdomen, and pelvis.
Results. Only scores from students participating in both Phase Iand Phase II (N = 57) were used in the analysis. After completingtheir MS3 clerkship, students scored significantly better overall andin every anatomical region. Phase I and Phase II overall mean scoreswere 1.2 ± 1.1 vs. 4.6 ± 1.8 (p < 0.001). Students improved the mostwith respect to injuries of the head and chest and the area of leastimprovement was in interpreting CT scans of the abdomen. Althoughimprovements in reading radiographic images were noted after theclerkship year, students accurately diagnosed only 46% of life-threateningimages on CT scan in the trauma setting.
Conclusions. These results indicated that enhanced education isneeded for medical students to interpret CT scans.Kans J Med 2018;11(4):91-94.