bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing summertime chemical boundary conditions for airmasses entering the US West Coast
Authors: Pfister G. G. , Parrish D. , Worden H. , Emmons L. K. , Edwards D. P. , Wiedinmyer C. , Diskin G. S. , Huey G. , Oltmans S. J. , Thouret V. , Weinheimer A. , Wisthaler A.
Published: November 2010

Abstract. The objective of this study is to analyze the pollution inflow into California during summertime and how it impacts surface air quality through combined analysis of a suite of observations and global and regional models. The focus is on the transpacific pollution transport investigated by the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission in June 2008. Additional observations include satellite retrievals of carbon monoxide and ozone by the EOS Aura Tropospheric Emissions Spectrometer (TES), aircraft measurements from the MOZAIC program and ozonesondes. We compare chemical boundary conditions (BC) from the MOZART-4 global model, which are commonly used in regional simulations, with measured concentrations to quantify both the accuracy of the model results and the variability in pollution inflow. Both observations and model reflect a large variability in pollution inflow on temporal and spatial scales, but the global model captures only about half of the observed free tropospheric variability. Model tracer contributions show a large contribution from Asian emissions in the inflow. Recirculation of local US pollution can impact chemical BC, emphasizing the importance of consistency between the global model simulations used for BC and the regional model in terms of emissions, chemistry and transport. Aircraft measurements in the free troposphere over California show similar concentration range, variability and source contributions as free tropospheric air masses over ocean, but caution has to be taken that local pollution aloft is not misinterpreted as inflow. A flight route specifically designed to sample boundary conditions during ARCTAS-CARB showed a prevalence of plumes transported from Asia and thus may not be fully representative for average inflow conditions. Sensitivity simulations with a regional model with altered BCs show that the temporal variability in the pollution inflow does impact modeled surface concentrations in California. We suggest that time and space varying chemical boundary conditions from global models provide useful input to regional models, but likely still lead to an underestimate of peak surface concentrations and the variability associated with long-range pollution transport.
Atmospheric homogeneous nucleation of H2SO4 and H2O
Authors: Benson D. R. , Erupe M. E. , Yu J. H. , Markovich A. , Lee S.-H.
Published: November 2010

Abstract. We report laboratory observations of H2SO4 and H2O homogeneous nucleation made under atmospherically relevant conditions ([H2SO4] of 106 – 107 cm−3 and 287 K). Our observations show that nucleation takes place at [H2SO4] of 106 – 107 cm−3, as observed in the atmosphere. The slope of nucleation rate (J) vs. [H2SO4] ranges between 4–6, consistent with thermodynamic predictions of neutral H2SO4 clusters, but is higher than those observed in the atmosphere. These results indicate that ternary aerosol precursors are needed to reduce the slope to 1–2 in the atmosphere. This study also discusses the effects of experimental parameters on laboratory observation results, in order to properly interpret the experimental data.
Debris flow hazard modelling on medium scale: Valtellina di Tirano, Italy
Authors: Blahut J. , Horton P. , Sterlacchini S. , Jaboyedoff M.
Published: November 2010

Abstract. Debris flow hazard modelling at medium (regional) scale has been subject of various studies in recent years. In this study, hazard zonation was carried out, incorporating information about debris flow initiation probability (spatial and temporal), and the delimitation of the potential runout areas. Debris flow hazard zonation was carried out in the area of the Consortium of Mountain Municipalities of Valtellina di Tirano (Central Alps, Italy). The complexity of the phenomenon, the scale of the study, the variability of local conditioning factors, and the lacking data limited the use of process-based models for the runout zone delimitation. Firstly, a map of hazard initiation probabilities was prepared for the study area, based on the available susceptibility zoning information, and the analysis of two sets of aerial photographs for the temporal probability estimation. Afterwards, the hazard initiation map was used as one of the inputs for an empirical GIS-based model (Flow-R), developed at the University of Lausanne (Switzerland). An estimation of the debris flow magnitude was neglected as the main aim of the analysis was to prepare a debris flow hazard map at medium scale. A digital elevation model, with a 10 m resolution, was used together with landuse, geology and debris flow hazard initiation maps as inputs of the Flow-R model to restrict potential areas within each hazard initiation probability class to locations where debris flows are most likely to initiate. Afterwards, runout areas were calculated using multiple flow direction and energy based algorithms. Maximum probable runout zones were calibrated using documented past events and aerial photographs. Finally, two debris flow hazard maps were prepared. The first simply delimits five hazard zones, while the second incorporates the information about debris flow spreading direction probabilities, showing areas more likely to be affected by future debris flows. Limitations of the modelling arise mainly from the models applied and analysis scale, which are neglecting local controlling factors of debris flow hazard. The presented approach of debris flow hazard analysis, associating automatic detection of the source areas and a simple assessment of the debris flow spreading, provided results for consequent hazard and risk studies. However, for the validation and transferability of the parameters and results to other study areas, more testing is needed.
Marginal zone B cell lymphomas with extensive plasmacytic differentiation are neoplasms of precursor plasma cells
Authors: Meyerson Howard J. , Bailey Jeffrey , Miedler John , Olobatuyi Felix
Published: November 2010

Occasional marginal zone lymphomas have extensive plasmacytic differentiation (P‐MZL). We present an argument based on our data and previous published observations that P‐MZL represent neoplasms of precursor plasma cells. Five P‐MZL were analyzed by flow cytometry and the phenotype was compared with conventional MZL, plasma cell myeloma (PCM), reactive plasmacytoses (RP), and normal marrow plasma cells. The clonal cells in four of five P‐MZL were CD19(+), CD20(dim/−), CD38(bright), CD45(++), CD56(−), CD138(−), and surface light chain(dim/−). One case was CD56(+), CD138(+), and CD19(−). A separate clonal mature B cell population [CD20(+), CD79b(+)] was not detected in any of these tumors. Hierarchical clustering demonstrated similarity between the neoplastic cells in four of the five P‐MZL with plasma cells in RP comprised of precursor plasma cells. Analysis of normal bone marrow plasma cells revealed a CD45(++)CD38(bright)CD19(+)CD138(−/+) precursor plasma cell population similar to the plasma cells in RP and P‐MZL and a very small population of mature CD45(+/−)CD38(bright)CD138(+)CD19(−) plasma cells resembling the neoplastic cells in PCM. The findings suggest that P‐MZL represents a malignancy of a plasma cell stage of differentiation distinct from the plasma cell stage corresponding to PCM. We propose the term precursor plasma cell neoplasm for these tumors. ©2010 International Clinical Cytometry Society
Managing high‐potency active pharmaceutical ingredients—A drug sponsor's guide
Authors: Wollowitz Susan
Published: November 2010

The wide interest in developing improved therapies for cancer has led to a dramatic increase in the number of highly potent active pharmaceutical ingredients (HAPIs) under development and in use today. The following is an overview of the “cradle‐to‐grave” health risk issues that must be addressed during drug development of a HAPI, as seen from a drug sponsor's perspective. Although much of the handling of the drug may be outsourced, this article points out the principal responsibilities of the drug sponsor and what they need to know about the responsibilities of the CMOs and CROs in handling HAPIs to ensure the most effective partnership. The major focus is on manufacturing activity, but upstream and downstream issues are also presented. Drug Dev Res 71:420–428, 2010. © 2010 Wiley‐Liss, Inc.
Intrauterine administration of peripheral blood mononuclear cells enhances early development of the pre‐implantation bovine embryo
Authors: Ideta Atsushi , Hayama Koh , Nakamura Yuuki , Sakurai Toshihiro , Tsuchiya Kanami , Tanaka Sachi , Yamaguchi Takahiro , Fujiwara Hiroshi , Imakawa Kazuhiko , Aoyagi Yoshito
Published: November 2010

Intrauterine administration of peripheral blood mononuclear cells (PBMCs) prior to bovine embryo transfer (ET) was previously shown to improve the pregnancy rate. To better understand how PBMCs improve the pregnancy rate, we examined gene expression in the cells from uterine lumen and evaluated the morphology of bovine pre‐attachment embryos in utero following intrauterine administration of PBMCs. On day 3 of the estrous cycle (day 0 = estrous), bovine PBMCs were isolated and suspended in RPMI 1640, and were incubated for 24 hr. The cultured PBMCs were administered non‐surgically to the uterine horn ipsilateral to the corpus luteum on day 4 of the estrous cycle (PBMC group). On day 9, endometrial–luminal lymphoid cells from uterine lumen ipsilateral to the corpus luteum were collected by uterine flushing. Transcripts for macrophage‐colony stimulating factor in the lymphoid cells were more abundant in the PBMC group than in the control group (P < 0.05). On day 7 (of the separate experiments), five blastocysts were each transferred to the luminal area, to which PBMCs had been administered on day 4. These embryos were allowed to develop in utero until day 15 of gestation, when embryos were non‐surgically retrieved from the uterus. The average length of trophoblasts recovered from the PBMC group was significantly longer than that of the control group (51.6 ± 7.8 vs. 27.4 ± 6.0 mm, P < 0.05). Our results strongly suggest that intrauterine administration of PBMCs improves endometrial environment, which promotes early development of pre‐attachment conceptuses. Mol. Reprod. Dev. 77:954–962, 2010. © 2010 Wiley‐Liss, Inc.
The effects of supplier‐to‐buyer identification on operational performance—An empirical investigation of inter‐organizational identification in automotive relationships
Authors: Corsten Daniel , Gruen Thomas , Peyinghaus Marion
Published: November 2010

Over the past decade conceptual and empirical research in operations management has embraced the idea that collaborative supplier–buyer relationships are a source of competitive advantage for manufacturing firms. Anecdotal evidence from the Japanese and U.S. automotive industry and emerging research suggests that inter‐organizational identification of suppliers with their buyers, termed supplier‐to‐buyer identification, is an unexplored factor of relational advantage. This study presents a model and empirical test that supplier‐to‐buyer identification fosters superior operational performance by enhancing trust, supplier relation‐specific investments, and information exchange. Through a survey of 346 automotive supplier–buyer relationships, the findings show that supplier‐to‐buyer identification directly impacts supplier relationship‐specific investments and information exchange, although most of the latter effect is mediated by trust. The findings also indicate that supplier relation‐specific investments and information exchange play different but complementary roles in influencing operational performance. The results suggest new directions for supplier–buyer relationship research in operations management and important managerial implications.
The Biopsycho‐ecological Paradigm: A Foundational Theory for Medicine
Authors: Stineman Margaret Grace , Streim Joel E.
Published: November 2010

The current biomedical and psychosocial frameworks that form the conceptual basis of medicine today are insufficient to address the needs of the medically complex and environmentally challenged populations of patients often cared for by physical medicine and rehabilitation specialists. The expanded biopsycho‐ecological model of health, illness, injury, and disability operating through mechanisms of Health Environmental Integration (HEI) encourages a more complete understanding of illness, injury, activity limitation, and participation restriction as arising at the interface between the person and the environment. HEI recognizes complex interacting multilevel functional hierarchies beginning at the cellular level and ending at the individual's experience of the environment. Although the foci of illness and injury are within the body and mind, the physical and social environments contain elements that can cause or exacerbate disease and barriers that interact in ways that lead to injuries and disabilities. Furthermore, these environments hold the elements from which treating agents, facilitators, and social supports must be fashioned. The highly integrative biopsycho‐ecological framework provides an expanded basis for understanding the objective causes and subjective meanings of disabilities. Disabilities are reduced through HEI by seeking to maximally integrate the body and mind (the self) with both the surrounding physical environment and other people in society. HEI offers mechanisms for interdisciplinary research, an expanded framework for education and empowerment, and a blueprint for optimizing day‐to‐day clinical care at both the individual patient and treatment population levels in the ever‐changing scientific, political, and policy environments.
Physical Therapy Workforce in the United States: Forecasting Nationwide Shortages
Authors: Zimbelman Janice L. , Juraschek Stephen P. , Zhang Xiaoming , Lin Vernon W.‐H.
Published: November 2010

Objective

To examine current and future physical therapy (PT) job surplus/shortage trends across the United States.

Design

Forecast models and grading methodology previously published for nursing were used to evaluate individual state PT job shortages from 2008 to 2030.

Setting

Not applicable.

Participants

Not applicable.

Methods

The forecast model used to project PT job supply and demand accounted for changes in age and population size on the basis of estimates from the U.S. Census Bureau for each of the 50 states. PT shortages were assigned letter grades on the basis of shortage ratios (difference between demand and supply per 10,000 people) to evaluate PT shortages and describe the changing PT workforce in each state.

Results

On the basis of current trends, demand for PT services will outpace the supply of PTs within the United States. Shortages are expected to increase for all 50 states through 2030. By 2030, the number of states receiving below‐average grades for their PT shortages will increase from 12 to 48. States in the Northeast are projected to have the smallest shortages, whereas states in the south and west are projected to have the largest shortages.

Conclusion

These data serve to provide health professionals, policy makers, and stakeholders with a means of assessing current and future PT needs. Discussion of the issues surrounding PT shortages and ongoing assessment of supply and demand must ensue to mitigate projected shortages. Although our model has several limitations and may be oversimplified, it is the first attempt to use available, creditable data to examine both supply and demand for the entire country. Follow‐up studies that use more complex modeling are needed to adequately forecast future trends beyond that accomplished in the current article. Monitoring trends over time is critical to maintain an appropriate balance between PT supply and demand that meets the population needs.
Are Electrodiagnostic Study Findings Related to a Patient's Response to Epidural Steroid Injection?
Authors: Marchetti Jason , Verma‐Kurvari Sunita , Patel Nayan , Ohnmeiss Donna D.
Published: November 2010

Objective

To determine if improvements in pain after epidural steroid injections (ESIs) were related to electromyographic (EMG) findings in patients with radicular symptoms and clinical findings consistent with radiculopathy.

Design

Retrospective chart review.

Setting

Multisite spine clinic.

Patients

Data were analyzed from 89 patients who had needle EMG within 6 months of ESI between 2005 and 2008.

Methods

Clinical and demographic data and results of EMG testing from qualified patients were recorded from patient charts at least 10 days after ESI. Evidence of radiculopathy on EMG reports was classified as positive, normal, or equivocal. In all 3 EMG groups, the percentage of patients who had 50% improvement in leg pain after ESI was noted. As a secondary analysis, improvement in pre‐ESI to post‐ESI leg and back pain scores in the EMG groups were compared.

Outcome Measurements

The clinical outcome measurements were visual analog scale (VAS) scores assessing leg and back pain. ESI relief was defined as at least 50% improvement in the VAS score assessing leg pain after the injection.

Results

EMG findings were normal in 47.2%, positive in 31.5%, and equivocal in 21.3% of patients. No significant differences were found in the percentages of patients experiencing a positive response to the ESI with respect to EMG findings. Forty‐three percent of patients with normal EMG findings (18/42), 25.0% of patients with positive EMG findings (7/28), and 31.6% patients with equivocal EMG findings (6/19) had relief after ESI. In all 3 EMG groups, a statistically significant improvement in mean VAS scores was found after ESI.

Conclusions

Mean leg and back pain scores improved significantly after ESI in all 3 EMG groups: those with positive, normal, and equivocal findings. Results of this study do not suggest that ESI is contraindicated in patients with normal EMG findings.
Characteristics and Predictors of Short‐Term Outcomes in Individuals Self‐selecting Yoga or Physical Therapy for Treatment of Chronic Low Back Pain
Authors: Evans Dian Dowling , Carter Michael , Panico Richard , Kimble Laura , Morlock Jennifer T. , Spears Manjula Judith
Published: November 2010

Objective

To compare clinical and demographic characteristics of individuals self‐selecting yoga or physical therapy (PT) for treatment of chronic low back pain (cLBP) and to examine predictors of short‐term pain and functional outcomes.

Design

Descriptive, longitudinal study.

Settings

A hospital‐based clinic that offers modified integral yoga classes for cLBP and 2 outpatient PT clinics that offer exercise‐based PT.

Participants

Adults (n = 53) with cLBP ≥12 weeks: yoga (n = 27), PT (n = 26).

Methods

Yoga participants attended a 6‐week, once weekly, 2‐hour yoga class. PT participants underwent twice weekly, 1‐hour individualized PT. Data were collected at baseline and at 6 weeks. Groups were compared by using χ2 and independent samples t‐tests. Hierarchical linear regression was used to predict treatment outcomes.

Main Outcome Measures

Disability (Roland Morris Disability Questionnaire), health status (Rand Short Form 36 Health Survey 1.0), pain bothersomeness (numerical rating scale), back pain self‐efficacy (Back Pain Self‐Efficacy Scale), and treatment satisfaction.

Results

At baseline, yoga participants were significantly less disabled (P = .013), had higher health status (P = .023), greater pain self‐efficacy (P = .012), and less average pain bothersomeness (P = .001) compared with PT participants. At 6 weeks, when controlling for baseline group differences, greater pain self‐efficacy was the strongest predictor for reduced pain and higher function for the entire sample. A significant group interaction by baseline pain self‐efficacy predicted disability at 6 weeks. PT participants with low pain self‐efficacy reported significantly greater disability than those with high pain self‐efficacy. Yoga participants with low and high pain self‐efficacy had similar disability outcomes.

Conclusion

These findings strengthen evidence that self‐efficacy is associated with cLBP outcomes, especially in individuals self‐selecting PT. Further research to evaluate outcomes after yoga and PT in participants with low pain self‐efficacy is needed.
Spinal Mobilization of Postpartum Low Back and Pelvic Girdle Pain: An Evidence‐Based Clinical Rule for Predicting Responders and Nonresponders
Authors: Al‐Sayegh Nowall A. , George Susan E. , Boninger Michael L. , Rogers Joan C. , Whitney Susan L. , Delitto Anthony
Published: November 2010

Objective

To develop a clinical prediction rule (CPR) for identifying postpartum women with low back pain (LBP) and/or pelvic girdle pain (PGP) whose functional disability scores improve with a high‐velocity thrust technique (HVTT) conducted by a physical therapist.

Design

Prospective cohort.

Setting

Outpatient physical therapy departments.

Participants

Sixty‐nine postpartum women referred to physical therapy with the complaint of LBP and/or PGP.

Methods

Subjects underwent a physical examination and a HVTT to the lumbopelvic region.

Main Outcome Measures

Success with treatment was determined by the use of percent changes in disability scores and served as the reference standard for determining accuracy of the examination variables. Variables with univariate prediction of success and nonsuccess were combined into multivariate CPRs.

Results

Fifty‐five subjects (80%) had success with the HVTT. A CPR for success with 4 criteria was identified. The presence of 2 of 4 criteria (positive likelihood ratio = 3.05) increased the probability of success from 80% to 92%. A CPR for treatment failure with 3 criteria was identified. The presence of 2 of 3 criteria (positive likelihood ratio = 11.79) increased the probability of treatment failure from 20% to 75%.

Conclusions

The pretest probability of success (80%) is sufficient to reassure the clinician about the decision to use a HVTT to the lumbopelvic region in postpartum women with LBP and/or PGP. If 2 of 3 criteria for treatment failure are met in the CPR, an alternative approach is warranted. An intervention such as the HVTT is compelling, given the need to minimize pharmaceutical remedies in women who are potentially breast‐feeding post partum.
Dimensionality of Measures for Severe Unilateral Ankle Arthritis
Authors: Cook Chad , Queen Robin M. , Slaven Emily J. , DeOrio James K. , Easley Mark E. , Nunley James A.
Published: November 2010

Objective

To analyze the dimensionality of 2 self‐report outcome measures (Foot/Ankle Disability Index [FADI] and Short‐Form [SF]‐36), 3 biomechanical measures (stance and step symmetry measures, gait speed, and step width), 2 physical‐performance measures (timed get‐up and go [TUG] and 4‐square step test [4SST]), and 1 clinician‐report outcome measure (American Orthopaedic Foot and Ankle Society [AOFAS] Hindfoot Scale) in a patient population with unilateral ankle arthritis. These measures captured the following functions: mobility and speed, pain and its relationship to function, social integration, and symmetry and efficiency of gait.

Design

Case series design.

Setting

Biomechanical research laboratory adjacent to a busy orthopedic clinical practice.

Patients

Seventy‐nine consecutive patients with unilateral traumatic arthritis who were candidates for a total ankle replacement.

Methods

An exploratory factor analysis with oblimin rotation was performed to determine the dimensions of the physical performance, biomechanical, self‐report, and clinician‐report measures.

Main Outcome Measurements

Outcomes measures included the SF‐36 and pertinent subscales, gait speed, the 4SST, the TUG, the FADI, the AOFAS Hindfoot Scale, and biomechanical measures of step width, step symmetry, and stance symmetry.

Results

Four distinct dimensions were captured during factor analysis. Factor 1 included the TUG, gait speed, the 4SST, and step width; factor 2 included the FADI, the SF‐36 bodily pain score, and the SF‐36 physical function score; factor 3 included the biomechanical scores of stance symmetry ratio and the step symmetry ratio; and factor 4 included SF‐36 social functioning and the AOFAS Hindfoot Scale.

Conclusions

Findings suggest that various outcome measures for the ankle capture different dimensions and should be considered when evaluating the presence of disability or long‐term change in outcome.
Planarization of InP pyramids containing integrated InAs quantum dots and their optical properties
Authors: Wang Hao , Yuan Jiayue , van Veldhoven René P. J. , de Vries Tjibbe , Smalbrugge Barry , Geluk Erik Jan , Nötzel Richard
Published: November 2010

Position-controlled InAs quantum dots (QDs) are integrated into planar InP structures by employing selective area growth of InP pyramids and regrowth by metalorganic vapor-phase epitaxy. A smooth surface morphology is obtained at elevated regrowth temperature due to suppression of three-dimensional growth on the pyramids. The height differences are less than 30 nm after nominal 700 nm InP regrowth at 640 °C. Most important, the integrated QDs maintain good optical quality after regrowth for the realization of integrated nanophotonic devices and circuits operating at telecom wavelengths.
Determining concentration depth profiles of thin foam films with neutral impact collision ion scattering spectroscopy
Authors: Ridings Christiaan , Andersson Gunther G.
Published: November 2010

Equipment is developed to measure the concentration depth profiles in foam films with the vacuum based technique neutral impact collision ion scattering spectroscopy. Thin foam films have not previously been investigated using vacuum based techniques, hence specialized methods and equipment have been developed for generating and equilibrating of foam films under vacuum. A specialized film holder has been developed that encloses the foam film in a pressure cell. The pressure cell is air-tight except for apertures that allow for the entrance and exit of the ion beam to facilitate the analysis with the ion scattering technique. The cell is supplied with a reservoir of solvent which evaporates upon evacuating the main chamber. This causes the cell to be maintained at the vapor pressure of the solvent, thus minimizing further evaporation from the films. In order to investigate the effect of varying the pressure over the films, a hydrostatic pressure is applied to the foam films. Concentration depth profiles of the elements in a thin foam film made from a solution of glycerol and the cationic surfactant hexadecyltrimethylammonium bromide (C16TAB) were measured. The measured concentration depth profiles are used to compare the charge distribution in foam films with the charge distribution at the surface of a bulk solution. A greater charge separation was observed at the films’ surface compared to the bulk surface, which implies a greater electrostatic force contribution to the stabilization of thin foam films.
Transport properties of high-temperature Jupiter atmosphere components
Authors: Bruno D. , Catalfamo C. , Capitelli M. , Colonna G. , De Pascale O. , Diomede P. , Gorse C. , Laricchiuta A. , Longo S. , Giordano D. , Pirani F.
Published: November 2010

Transport properties of high-temperature helium and hydrogen plasmas as well as Jupiter atmosphere have been calculated for equilibrium and nonequilibrium conditions using higher approximations of the Chapman–Enskog method. A complete database of transport cross sections for relevant interactions has been derived, including minority species, by using both ab initio and phenomenological potentials. Inelastic collision integrals terms, due to resonant charge-exchange channels, have been also considered.
Thrust stand for vertically oriented electric propulsion performance evaluation
Authors: Moeller Trevor , Polzin Kurt A.
Published: November 2010

A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally stable system. Motion of the pendulum arm is transferred through a balance mechanism to a secondary arm on which deflection is measured. A noncontact light-based transducer is used to measure displacement of the secondary beam. The members experience very little friction, rotating on twisting torsional pivots with oscillatory motion attenuated by a passive, eddy-current damper. Displacement is calibrated using an in situ thrust calibration system. Thermal management and self-leveling systems are incorporated to mitigate thermal and mechanical drifts. Gravitational force and torsional spring constants associated with flexure pivots provide restoring moments. An analysis of the design indicates that the thrust measurement range spans roughly four decades, with the stand capable of measuring thrust up to 12 N for a 200 kg thruster and up to approximately 800 mN for a 10 kg thruster. Data obtained from calibration tests performed using a 26.8 lbm simulated thruster indicated a resolution of 1 mN on 100 mN level thrusts, while those tests conducted on a 200 lbm thruster yielded a resolution of roughly 2.5 mN at thrust levels of 0.5 N and greater.
Comparative analysis of glass-formation in binary, ternary, and multicomponent alloys
Authors: Louzguine-Luzgin Dmitri V. , Miracle Daniel B. , Louzguina-Luzgina Larissa , Inoue Akihisa
Published: November 2010

In the present work we analyze the composition ranges over which bulk metallic glasses (BMGs) are produced in ternary, quaternary, and quinary amorphous alloys. The maximum diameter of the sample over which an amorphous structure can be retained, referred to as the critical diameter, Dc, is consistently large over specific composition ranges. For ternary BMGs, these most stable glasses are centered around the compositions, in decreasing order of accompanying Dc: A44B38C18, A44B43C13, A65B25C10, A56B32C12, A55B28C17, A70B20C10, and A65B20C15. As a general trend, the most stable glasses have the lowest concentrations of solvent atoms. Structural analysis using the efficient cluster packing model suggests that the best ternary glasses are near the isostructural composition, which represents the maximum degree of atomic confusion. Both Dc and ΔTx=Tx−Tg, the difference between the crystallization and glass transition temperatures, are larger in quaternary and quinary systems relative to typical values for ternary BMGs. Glass-forming ability increases with complexity of the alloy, i.e., increasing number of alloying elements. The above results shed some light not only on compositional dependence of the formation of glassy phase but also its relation to the structure of the glasses.
Time-temperature-transformation measurements of FePt thin films in the millisecond regime using pulse laser processing
Authors: Inaba Yuki , Zana Iulica , Swartz Caleb , Kubota Yukiko , Klemmer Tim , Harrell J. W. , Thompson Gregory B.
Published: November 2010

A section of the time-temperature-transformation (TTT) curve has been measured in the millisecond regime to describe the A1 to L10 transformation of 10 nm FePt thin films. Short time annealing was accomplished using a pulsed neodymium-doped yttrium aluminum garnet laser operating at a wavelength of 1064 nm. The temperature-time profile of the films was measured using an optical pyrometer and a platinum thin film resistor and it was numerically modeled. Effective thermal pulse widths were determined from the time dependence of the atomic diffusion coefficient calculated from the measured temperature profile. The measured TTT diagram involving average order parameter is consistent with theoretical predictions of TTT diagrams involving ordered volume fraction and shows that partial ordering can be obtained with a single effective thermal pulse as short as 1.1 ms.
Effect of flux creep and viscous flux flow on flux-pinning-induced stress and magnetostriction in a long rectangular slab superconductor
Authors: Xue Feng , Yong Hua-Dong , Zhou You-He
Published: November 2010

The magnetoelastic problem for a superconductor slab placed in a time-dependent magnetic field is considered. Two major components of the flux (vortex) motion: flux creep and viscous flux flow have been considered, among which the logarithmic dependence of activation energy on the current density is assumed for the creep problem. As one of the two parts of flux motion, viscous effect of flux flow dominates the motion of fluxoids at high flux velocities and enhances the maximum tensile stress and the magnetostriction remarkably after zero-field cooling. However, the effect of flux creep cannot be omitted at low magnetic field sweep rate (Ḃa) and is helpful to alleviate tensile stresses within the superconductor. Apart from this, the position (x0) where the maximum tensile stress occurs has a similar dependence on the sweep rate (Ḃa) as the stress value itself. All the results indicate that the sweep rate (Ḃa) should be considered in the magnetization process in order to avoid cracking within the superconductor slab.
Structural and piezoelectric properties of high-density (Bi0.5K0.5)TiO3–BiFeO3 ceramics
Authors: Matsuo Hiroki , Noguchi Yuji , Miyayama Masaru , Suzuki Muneyasu , Watanabe Akira , Sasabe Shuji , Ozaki Tomoatsu , Mori Shigeo , Torii Shuki , Kamiyama Takashi
Published: November 2010

The crystal structures and dielectric, polarization, and piezoelectric properties of high-density x(Bi0.5K0.5)TiO3–(1−x)BiFeO3 ceramics were investigated. The results obtained using x-ray and neutron powder diffractions and transmission electron microscopy showed that a morphotropic phase boundary between the rhombohedral (ferroelectric) and pseudocubic (ferroelectric) phases is present in 0.4<x<0.43. Ceramics with x=0.4 exhibited a large remanent polarization of 52 μC/cm2 at 25 °C and their piezoelectric properties were maintained up to 300 °C. It is suggested that the presence of nanosized domains with a polar rhombohedral structure observed for x=0.4 is the origin of relaxor-like dielectric properties.
Control of ideal and resistive magnetohydrodynamic modes in reversed field pinches with a resistive wall
Authors: Richardson A. S. , Finn J. M. , Delzanno G. L.
Published: November 2010

Numerical studies of magnetohydrodynamic (MHD) instabilities with feedback control in reversed field pinches (RFPs) are presented. Specifically, investigations are performed of the stability of m=1 modes in RFPs with control based on sensing the normal and tangential magnetic fields at the resistive wall and applying two-parameter feedback proportional to these fields. The control scheme is based on that of [J. M. Finn, Phys. Plasmas 13, 082504 (2006)], which is here modified to use a more realistic plasma model. The plasma model now uses full resistive MHD rather than reduced MHD, and it uses three realistic classes of equilibrium parallel current density profiles appropriate to RFPs. Results with these modifications are in qualitative agreement with [J. M. Finn, Phys. Plasmas 13, 082504 (2006)]: the feedback can stabilize tearing modes (with resistive or ideal-wall) and resistive wall ideal modes. The limit for stabilization is again found to be near the threshold for ideal modes with an ideal-wall. In addition to confirming these predictions, the nature of the instabilities limiting the range of feedback stabilization near the ideal-wall ideal-plasma threshold are studied, and the effects of viscosity, resistive wall time, and plasma resistivity are reported.
Disorder induced magnetism and electrical conduction in La doped Ca2FeMoO6 double perovskite
Authors: Poddar Asok , Bhowmik R. N. , Muthuselvam I. Panneer
Published: November 2010

We report the magnetism and electrical transport properties of La doped Ca2FeMoO6 double perovskite. Reduction in magnetic moment, nonmonotonic variation in magnetic ordering temperature (TC), increasing magnetic hardness, low temperature resistivity upturn, and loss of metallic conductivity are some of the major changes that we observed due to La doping induced disorder in double perovskite structure. The increase in magnetic disorder in La doped samples and its effect on TC is more consistent with the mean field theory. The modification in electronic band structure due to La doping is understood by establishing a correlation between the temperature dependence of electrical conductivity and thermoelectric power.
Spin-polarized current generated by carbon chain and finite nanotube
Authors: Guo Y. D. , Yan X. H. , Xiao Y.
Published: November 2010

Inspired by recent progress of experimental fabrication of carbon structure [Borrnert et al., Phys. Rev. B 81, 085439 (2010)], we proposed a scheme to generate spin-polarized current based on an all-carbon system consisting of carbon nanotube and chain. The transmission spectra are calculated based on density functional theory combined with nonequilibrium Green’s function method. It is found that the spin-polarized current can be achieved in the proposed system by partial contact between nanotube and chain, without using the dopants, ferromagnetic electrodes, and external electric field. Moreover, our results show that the device containing carbon nanotubes with large length and diameter can produce the current with 100% spin polarization, which is essential for spintronic devices. Physical mechanisms and the comparison with the results of graphene are also discussed.
Indirect optical transition due to surface band bending in ZnO nanotubes
Authors: Yang L. L. , Zhao Q. X. , Israr M. Q. , Sadaf J. R. , Willander M. , Pozina G. , Yang J. H.
Published: November 2010

ZnO nanotubes (ZNTs) have been successfully evolved from ZnO nanorods (ZNRs) by a simple chemical etching process. Two peaks located at 382 and 384 nm in the UV emission region has been observed in the room temperature photoluminescence (PL) spectrum of ZNTs since the surface band bending in ZNTs induces the coexistence of indirect and direct transitions in their emission process. In addition, a strong enhancement of total luminescence intensity at room temperature in ZNTs has also be observed in comparison with that of ZNRs. Both temperature-dependent PL and time-resolved PL results not only further testify the coexistence of indirect and direct transitions due to the surface band bending but also reveal that less nonradiative contribution to the emission process in ZNTs finally causes their stronger luminescence intensity.
Structural evolution of Re (0001) thin films grown on Nb (110) surfaces by molecular beam epitaxy
Authors: Welander Paul B.
Published: November 2010

The heteroepitaxial growth of Re (0001) films on Nb (110) surfaces has been investigated. Nb/Re bilayers were grown on A-plane sapphire—α-Al2O3 (112¯0)—by molecular beam epitaxy. While Re grew with a (0001) surface, the in-plane epitaxial relationship with the underlying Nb could be best described as a combination of Kurdjumov–Sachs and Nishiyama–Wassermann orientations. This relationship was true regardless of Re film thickness. However, an evolution of the surface morphology with increasing Re thickness was observed, indicative of a Stranski–Krastanov growth mode. Re (0001) layers less than 150 Å thick were atomically smooth, with a typical rms roughness of less than 5 Å, while thicker films showed granular surface structures. And despite the presence of a substantial lattice misfit, the Re layer strain diminished rapidly and the Re lattice was fully relaxed by about 200 Å. The strain-free and atomically smooth surface of thin Re overlayers on Nb is ideal for the subsequent epitaxial growth of ultra-thin oxide tunnel barriers. Utilizing bcc/hcp (or bcc/fcc) heteroepitaxial pairs in advanced multilayer stacks may enable the growth of all-epitaxial superconductor/insulator/superconductor trilayers for Josephson junction-based devices and circuits.
A multipeak phenomenon of magnetoelectric coupling in Terfenol-D/P(VDF-TrFE)/Terfenol-D laminates
Authors: Fang F. , Shan S. C. , Yang W.
Published: November 2010

The magnetoelectric (ME) coupling in Terfenol-D/P(VDF-TrFE)/Terfenol-D laminate is investigated as a function of the applied static magnetic field (Hs) and the frequency of the alternating magnetic field. A three-dimensional surface chart of ME coefficients (αME) versus Hs and frequency of the alternating magnetic field is drawn. The landscape highlights three strings of resonance peaks and an additional peak corresponding to the maximum of the piezomagnetic coefficient d11,m of the Terfenol-D plate. Based on the constitutive relations of Terfenol-D, the resonances are found to be caused by the mechanical oscillation of the magnetic layer under the applied alternating magnetic field. The ferromagnetic resonance frequency can be tuned by varying Hs. Finite element simulations fit well with the experimental data. That enables us to conclude that three resonance modes correspond to oscillations in length-, width-, and biaxial directions, respectively.
Study of the photoluminescence and photoelectric properties of Pb1−XCdXI2 alloys
Authors: Furyer M. S. , Skubenko P. A. , Bukivskij P. M. , Tarakhan L. M. , Chesnokov E. D. , Vertegel I. G. , Ovcharenko A. I. , Ivanova L. S. , Gamernyk R. V. , Gnatenko Yu. P.
Published: November 2010

The low-temperature photoluminescence (PL), photodiffusion current, photoconductivity (PC), and nuclear quadrupolar resonance spectra of the layered PbI2 single crystals and Pb1−XCdXI2 alloys were investigated. It was shown that the alloys are formed for any composition ratio and they have monopolar (hole) PC. The exciton PL band energy depends linearly on the composition ratio. It was found that the PbI2 clusters with various sizes are formed in Pb1−XCdXI2 alloys. For X≤0.50 the clusters are large [more than the Bohr radius of exciton in PbI2 (RB)] while for X=0.50 they are both large and small (smaller than RB). It was shown that these clusters are formed within the crystal layer. For Pb1−XCdXI2 alloys with X=0.70 the broad PL band at 2.1 eV is observed. This band is caused by the formation of the self-trapping excitons in PbI2 clusters. It was found that this PL band determines the emission of the alloys at T=300 K.
Electrical characteristics of Au and Ag Schottky contacts on Nb-1.0 wt %-doped SrTiO3
Authors: Cui Yimin , Yin Sheng , Wang Dandan , Xing Guozhong , Leng SengHwee , Wang Rongming
Published: November 2010

The (Au,Ag)/Nb-1.0 wt %-doped SrTiO3 (NSTO), i.e., Au/NSTO, Ag/NSTO, Ag/Au/NSTO, and Au/Ag/NSTO junctions were fabricated by magnetic controlled sputtering and annealing process. Backward diodelike behaviors were observed in all as-prepared samples, and forward rectifying characteristics were gradually developed in the four junctions after annealed in oxygen at 400 °C, 550 °C, 700 °C, and 850 °C, respectively. Compared with the Ag/NSTO junctions, the Au/NSTO junctions showed higher temperature evolving procedure of forward rectifying behavior. Moreover, ideal Schottky behaviors appeared in the samples annealed at 850 °C, which were attributed to the formation of interface states. X-ray photoelectron spectroscopy and secondary ion mass spectrometry analysis showed that the interface states mainly originated from the migration of metal into NSTO matrix and the changes in chemical composition at the metal/NSTO interfaces. The results of current-voltage measurements reveal that annealing at higher temperature alters the interface barrier and thereby ameliorates the stability of leakage current remarkably.
In situ observation of self-organizing nanodot formation under nanosecond-pulsed laser irradiation on Si surface
Authors: Watanabe S. , Yoshida Y. , Kayashima S. , Yatsu S. , Kawai M. , Kato T.
Published: November 2010

An in situ observation of the formation of a laser-irradiation-induced nanodot array on a Si surface was performed using a pulsed-laser-equipped high-voltage electron microscope (laser-HVEM). Under multiple nanosecond (ns) pulsed laser irradiation shots, atomic clusters were first formed and distributed on the surface in order to grow them epitaxially into protruded dots with diameters of ten nanometers or less. This is followed by their diffusion induced by successive laser shots to cannibalize and merge them into a ripple line with aligned, larger dots. We conclude that the present subwavelength two-dimensionally-ordered nanodot array is formed by self-organization under pulsed laser irradiation.
Magnetic perturbation and associated energies of the antiphase boundaries in ordered Ni3Al
Authors: Manga Venkateswara Rao , Saal James E. , Wang Yi , Crespi Vincent H. , Liu Zi-Kui
Published: November 2010

The anisotropy of antiphase boundary (APB) energies in ordered L12–Ni3Al is studied, owing to its importance in understanding the anomalous flow behavior of this intermetallic compound. We report first-principle calculations for two types of APBs in the ordered compound: (001) and (111). The magnetic perturbations associated with these APBs are calculated as a function of supercell size to ensure that their periodic images are isolated both magnetically and elastically. The magnetic perturbation associated with the (111) APB is wider than that of the (001) APB. The fully relaxed, spin-polarized APB energies for (001) and (111) APBs are calculated to be 82 mJ/m2 and 177 mJ/m2, respectively. The resulting anisotropy ratio of σ(111)/σ(001)=2.16, which is significantly higher than previously reported values, suggests that cross-slip between (001) and (111) is highly favorable.
A novel micropump droplet generator for aerosol drug delivery: Design simulations
Authors: Su Guoguang , Longest P. Worth , Pidaparti Ramana M.
Published: November 2010

One challenge of generating a liquid aerosol is finding an efficient way to break up bulk amounts of the compound into micron-sized droplets. Traditional methods of aerosol generation focus on the principle of creating the liquid droplets by blowing air at high speed over or through a liquid. In this study, a novel micropump droplet generator (MDG) is proposed based on a microfluidics device to produce monodisperse droplets on demand (DoD). The micropump design was employed to both pump the fluid into the air and to encourage droplet breakup and aerosol formation. Computational simulation modeling of the new MDG was developed and validated with comparisons to experimental data for current generators. The device was found to produce an aerosol similar to a vibrating orifice DoD device. Most importantly, the input power required by the newly proposed device (MDG) was several orders of magnitude below existing DoD generators for a similar droplet output. Based on the simulation results obtained in comparison with current DoD generators, the MDG device performed effectively at higher frequencies, smaller nozzle diameters, and regardless of the liquid viscosity of the solution.
Artificial atoms on semiconductor surfaces
Authors: Tisdale W. A. , Zhu X.-Y.
Published: November 2010

Semiconductor nanocrystals are called artificial atoms because of their atom-like discrete electronic structure resulting from quantum confinement. Artificial atoms can also be assembled into artificial molecules or solids, thus, extending the toolbox for material design. We address the interaction of artificial atoms with bulk semiconductor surfaces. These interfaces are model systems for understanding the coupling between localized and delocalized electronic structures. In many perceived applications, such as nanoelectronics, optoelectronics, and solar energy conversion, interfacing semiconductor nanocrystals to bulk materials is a key ingredient. Here, we apply the well established theories of chemisorption and interfacial electron transfer as conceptual frameworks for understanding the adsorption of semiconductor nanocrystals on surfaces, paying particular attention to instances when the nonadiabatic Marcus picture breaks down. We illustrate these issues using recent examples from our laboratory.