Results for “INTEREST GROUPS” — Page 93

DOE OSTI2015

TU-EF-BRD-00: The Science of QA

Research related to quality and safety has been a staple of medical physics academic activities for a long time. From very early on, medical physicists have developed new radiation measurement equipment and analysis techniques, created ever increasingly accurate dose calculation models, and have vastly improved imaging, planning, and delivery techniques. These and other areas of interest have improved the quality and safety of radiotherapy for our patients. With the advent of TG-100, quality and safety is an area that will garner even more research interest in the future. As medical physicists pursue quality and safety research in greater numbers, it is worthwhile to consider what actually constitutes research on quality and safety. For example, should the development of algorithms for real-time EPID-based in-vivo dosimetry be defined as “quality and safety” research? How about the clinical implementation of such as system? Surely the application of failure modes and effects analysis to a clinical process would be considered quality and safety research, but is this type of research that should be included in the medical physics peer-reviewed literature? The answers to such questions are of critical importance to set researchers in a direction that will provide the greatest benefit to our field and the patients we serve. The purpose of this symposium is to consider what constitutes research in the arena of quality and safety and differentiate it from other research directions. The key distinction here is developing the tool itself (e.g. algorithms for EPID dosimetry) vs. studying the impact of the tool with some quantitative metric. Only the latter would I call quality and safety research. Issues of ‘basic’ versus ‘applied’ quality and safety research will be covered as well as how the research results should be structured to provide increasing levels of support that a quality and safety intervention is effective and sustainable. Examples from existing peer-reviewed research will be used to highlight the main points. Historical, medical physicists have leveraged many areas of applied physics, engineering and biology to improve radiotherapy. Research on quality and safety is another area where physicists can have an impact. The key to further progress is to clearly define what constitutes quality and safety research for those interested in doing such research and the reviewers of that research. Learning Objectives: List several tools of quality and safety with references to peer-reviewed literature. Describe effects of mental workload on performance. Outline research in quality and safety indicators and technique analysis. Understand what quality and safety research needs to be going forward. Understand the links between cooperative group trials and quality and safety research.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-EF-BRD-01: Topics in Quality and Safety Research and Level of Evidence

Research related to quality and safety has been a staple of medical physics academic activities for a long time. From very early on, medical physicists have developed new radiation measurement equipment and analysis techniques, created ever increasingly accurate dose calculation models, and have vastly improved imaging, planning, and delivery techniques. These and other areas of interest have improved the quality and safety of radiotherapy for our patients. With the advent of TG-100, quality and safety is an area that will garner even more research interest in the future. As medical physicists pursue quality and safety research in greater numbers, it is worthwhile to consider what actually constitutes research on quality and safety. For example, should the development of algorithms for real-time EPID-based in-vivo dosimetry be defined as “quality and safety” research? How about the clinical implementation of such as system? Surely the application of failure modes and effects analysis to a clinical process would be considered quality and safety research, but is this type of research that should be included in the medical physics peer-reviewed literature? The answers to such questions are of critical importance to set researchers in a direction that will provide the greatest benefit to our field and the patients we serve. The purpose of this symposium is to consider what constitutes research in the arena of quality and safety and differentiate it from other research directions. The key distinction here is developing the tool itself (e.g. algorithms for EPID dosimetry) vs. studying the impact of the tool with some quantitative metric. Only the latter would I call quality and safety research. Issues of ‘basic’ versus ‘applied’ quality and safety research will be covered as well as how the research results should be structured to provide increasing levels of support that a quality and safety intervention is effective and sustainable. Examples from existing peer-reviewed research will be used to highlight the main points. Historical, medical physicists have leveraged many areas of applied physics, engineering and biology to improve radiotherapy. Research on quality and safety is another area where physicists can have an impact. The key to further progress is to clearly define what constitutes quality and safety research for those interested in doing such research and the reviewers of that research. Learning Objectives: List several tools of quality and safety with references to peer-reviewed literature. Describe effects of mental workload on performance. Outline research in quality and safety indicators and technique analysis. Understand what quality and safety research needs to be going forward. Understand the links between cooperative group trials and quality and safety research.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-EF-BRD-02: Indicators and Technique Analysis

Research related to quality and safety has been a staple of medical physics academic activities for a long time. From very early on, medical physicists have developed new radiation measurement equipment and analysis techniques, created ever increasingly accurate dose calculation models, and have vastly improved imaging, planning, and delivery techniques. These and other areas of interest have improved the quality and safety of radiotherapy for our patients. With the advent of TG-100, quality and safety is an area that will garner even more research interest in the future. As medical physicists pursue quality and safety research in greater numbers, it is worthwhile to consider what actually constitutes research on quality and safety. For example, should the development of algorithms for real-time EPID-based in-vivo dosimetry be defined as “quality and safety” research? How about the clinical implementation of such as system? Surely the application of failure modes and effects analysis to a clinical process would be considered quality and safety research, but is this type of research that should be included in the medical physics peer-reviewed literature? The answers to such questions are of critical importance to set researchers in a direction that will provide the greatest benefit to our field and the patients we serve. The purpose of this symposium is to consider what constitutes research in the arena of quality and safety and differentiate it from other research directions. The key distinction here is developing the tool itself (e.g. algorithms for EPID dosimetry) vs. studying the impact of the tool with some quantitative metric. Only the latter would I call quality and safety research. Issues of ‘basic’ versus ‘applied’ quality and safety research will be covered as well as how the research results should be structured to provide increasing levels of support that a quality and safety intervention is effective and sustainable. Examples from existing peer-reviewed research will be used to highlight the main points. Historical, medical physicists have leveraged many areas of applied physics, engineering and biology to improve radiotherapy. Research on quality and safety is another area where physicists can have an impact. The key to further progress is to clearly define what constitutes quality and safety research for those interested in doing such research and the reviewers of that research. Learning Objectives: List several tools of quality and safety with references to peer-reviewed literature. Describe effects of mental workload on performance. Outline research in quality and safety indicators and technique analysis. Understand what quality and safety research needs to be going forward. Understand the links between cooperative group trials and quality and safety research.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-EF-BRD-03: Mental Workload and Performance

Research related to quality and safety has been a staple of medical physics academic activities for a long time. From very early on, medical physicists have developed new radiation measurement equipment and analysis techniques, created ever increasingly accurate dose calculation models, and have vastly improved imaging, planning, and delivery techniques. These and other areas of interest have improved the quality and safety of radiotherapy for our patients. With the advent of TG-100, quality and safety is an area that will garner even more research interest in the future. As medical physicists pursue quality and safety research in greater numbers, it is worthwhile to consider what actually constitutes research on quality and safety. For example, should the development of algorithms for real-time EPID-based in-vivo dosimetry be defined as “quality and safety” research? How about the clinical implementation of such as system? Surely the application of failure modes and effects analysis to a clinical process would be considered quality and safety research, but is this type of research that should be included in the medical physics peer-reviewed literature? The answers to such questions are of critical importance to set researchers in a direction that will provide the greatest benefit to our field and the patients we serve. The purpose of this symposium is to consider what constitutes research in the arena of quality and safety and differentiate it from other research directions. The key distinction here is developing the tool itself (e.g. algorithms for EPID dosimetry) vs. studying the impact of the tool with some quantitative metric. Only the latter would I call quality and safety research. Issues of ‘basic’ versus ‘applied’ quality and safety research will be covered as well as how the research results should be structured to provide increasing levels of support that a quality and safety intervention is effective and sustainable. Examples from existing peer-reviewed research will be used to highlight the main points. Historical, medical physicists have leveraged many areas of applied physics, engineering and biology to improve radiotherapy. Research on quality and safety is another area where physicists can have an impact. The key to further progress is to clearly define what constitutes quality and safety research for those interested in doing such research and the reviewers of that research. Learning Objectives: List several tools of quality and safety with references to peer-reviewed literature. Describe effects of mental workload on performance. Outline research in quality and safety indicators and technique analysis. Understand what quality and safety research needs to be going forward. Understand the links between cooperative group trials and quality and safety research.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-EF-BRD-04: Summing It Up: The Future of Quality and Safety Research

Research related to quality and safety has been a staple of medical physics academic activities for a long time. From very early on, medical physicists have developed new radiation measurement equipment and analysis techniques, created ever increasingly accurate dose calculation models, and have vastly improved imaging, planning, and delivery techniques. These and other areas of interest have improved the quality and safety of radiotherapy for our patients. With the advent of TG-100, quality and safety is an area that will garner even more research interest in the future. As medical physicists pursue quality and safety research in greater numbers, it is worthwhile to consider what actually constitutes research on quality and safety. For example, should the development of algorithms for real-time EPID-based in-vivo dosimetry be defined as “quality and safety” research? How about the clinical implementation of such as system? Surely the application of failure modes and effects analysis to a clinical process would be considered quality and safety research, but is this type of research that should be included in the medical physics peer-reviewed literature? The answers to such questions are of critical importance to set researchers in a direction that will provide the greatest benefit to our field and the patients we serve. The purpose of this symposium is to consider what constitutes research in the arena of quality and safety and differentiate it from other research directions. The key distinction here is developing the tool itself (e.g. algorithms for EPID dosimetry) vs. studying the impact of the tool with some quantitative metric. Only the latter would I call quality and safety research. Issues of ‘basic’ versus ‘applied’ quality and safety research will be covered as well as how the research results should be structured to provide increasing levels of support that a quality and safety intervention is effective and sustainable. Examples from existing peer-reviewed research will be used to highlight the main points. Historical, medical physicists have leveraged many areas of applied physics, engineering and biology to improve radiotherapy. Research on quality and safety is another area where physicists can have an impact. The key to further progress is to clearly define what constitutes quality and safety research for those interested in doing such research and the reviewers of that research. Learning Objectives: List several tools of quality and safety with references to peer-reviewed literature. Describe effects of mental workload on performance. Outline research in quality and safety indicators and technique analysis. Understand what quality and safety research needs to be going forward. Understand the links between cooperative group trials and quality and safety research.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2013

A Programming Framework for Scientific Applications on CPU-GPU Systems

At a high level, my research interests center around designing, programming, and evaluating computer systems that use new approaches to solve interesting problems. The rapid change of technology allows a variety of different architectural approaches to computationally difficult problems, and a constantly shifting set of constraints and trends makes the solutions to these problems both challenging and interesting. One of the most important recent trends in computing has been a move to commodity parallel architectures. This sea change is motivated by the industry’s inability to continue to profitably increase performance on a single processor and instead to move to multiple parallel processors. In the period of review, my most significant work has been leading a research group looking at the use of the graphics processing unit (GPU) as a general-purpose processor. GPUs can potentially deliver superior performance on a broad range of problems than their CPU counterparts, but effectively mapping complex applications to a parallel programming model with an emerging programming environment is a significant and important research problem.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2022

Probing the solidification of quasicrystals via joint experiment and simulation (Final Report)

Quasicrystals (QCs) possess long-range positional order but non-crystallographic orientational order. Their classically ‘forbidden’ symmetry has long attracted the interest of scientists worldwide. Despite their frequent observation in both metal alloys and soft matter structures in the 35 years since their discovery, little is known about how QCs evolve from a liquid, amorphous, or crystalline precursor. In this project, we sought to resolve the enigma of QC self-assembly through a combined experimental and computational program. The Shahani group employed in situ electron and synchrotron X ray imaging to peer into the growth dynamics of QCs in a liquid, covering a broad range of length scales and solidification pathways. Glotzer's team developed new simulation models incorporating phasonic defects — which are unique to quasicrystals — and used this model to investigate two grains growing together, closely mimicking the experimental conditions. While QCs remain exceptional structures, most compounds in the realm of intermetallics adopt non-trivial geometries. In fact, only around 6% of phases are comprised of the simplest sphere packings that researchers so readily associate with metals. State-of-the-art knowledge of phase transformations at the outset of this collaborative project did not encompass the remaining 94% of intermetallic compounds that possess complex and aperiodic structure types. Therefore, we expect that outcomes from this project will have immediate and profound impact on synthesis and processing science: our efforts will be used to not only explain the growth dynamics of QCs but also complex intermetallics more broadly.

36 MATERIALS SCIENCE↗

NASA NTRS1973

Estimation and detection of signals in multiplicative noise

A class of detection-estimation problems on matrix Lie groups is defined in which the observation noise is multiplicative in nature. By examining the differential versions of the hypotheses, which are bilinear in nature, it is possible to derive the relevant likelihood ratio formula and the associated optimal estimation equations for the signal given the observations and the assumption that the signal is present. These estimation equations are of interest in their own right, in that they represent a finite dimensional optimal solution to a nonlinear estimation problem and can be viewed as consisting of a Kalman-Bucy filter along with the on-line computation of the solution of the associated Riccati equation, which is driven by the observations. The usefulness of these results is illustrated via an example concerning the detection of an actuator failure in a rigid body rotational control system.

Willsky, A. S.↗

NASA NTRS1992

Error analysis of optical correlators

With the growing interest in using binary phase only filters (BPOF) in optical correlators that are implemented on magnetooptic spatial light modulators, an understanding of the effect of errors in system alignment and optical components is critical in obtaining optimal system performance. We present simulations of optical correlator performance degradation in the presence of eight errors. We break these eight errors into three groups: 1) alignment errors, 2) errors due to a combination of component imperfections and alignment errors, and 3) errors which result solely from non-ideal components. Under the first group, we simulate errors in the distance from the object to the first principle plane of the transform lens, the distance from the second principle plane of the transform lens to the filter plane, and rotational misalignment of the input mask with the filter mask. Next we consider errors which result from a combination of alignment and component imperfections. These include errors in the transform lens, the phase compensation lens, and the inverse Fourier transform lens. Lastly we have the component errors resulting from the choice of spatial light modulator. These include contrast error and phase errors caused by the non-uniform flatness of the masks. The effects of each individual error are discussed, and the result of combining all eight errors under assumptions of reasonable tolerances and system parameters is also presented. Conclusions are drawn as to which tolerances are most critical for optimal system performance.

Ma, Paul W.↗

NASA NTRS1948

Bibliography of NACA and Other Reports on Air Inlets and Internal Flows

At the suggestion of the Subcommittee on Internal Flow, the National Advisory Committee for Aeronautics has assembled this bibliography on air inlet and internal flow data for aircraft. It was felt that the purpose of this publication, to furnish the engineer and researcher with a listing of theoretical and experimental studies related directly and indirectly to the field of internal flows, could be served best by presenting some of the more pertinent and interesting references. Thus this bibliography is not complete in its listing of internal flow reports from the NACA or from other sources. The works referenced here are, for the most part, those published before January 1948. To aid the investigator in finding references, the bibliography has been indexed according to subject matter. NACA reports and reports from other sources are grouped separately. The subject breakdown used may be found in the table of contents on the preceding pages.

Bibliographies and indexes↗

NASA NTRS2005

The Warm-Hot Intergalactic Medium

This grant is associated to a 5-year LTSA grant, on "Studying the Largest Reservoir of Baryons in the Universe: The Warm-Hot Intergalactic Medium". The first year of work within this program has been very rich, and has already produced several important results, as detailed in this paper. Table 2 of our original proposal justification, listed the planned year-by-year program, divided into two sub-fields: (A) the study of the z=0 (or Local Group WHIM) system, and (B) the study of the z greater than 0 (i.e- intervening WHIM) systems. For each of the two sub-fields we had planned to analyze, in the first year, a number of archival (Chandra, XMM and FUSE) and new (if observed) sightlines. Moreover, the plan for the z=0 system included the search for new interesting sightlines. We have accomplished all these tasks.

Hayes, Jeffrey↗

NASA NTRS2015

The ISECG* Global Exploration Roadmap as Context for Robotic and Human Exploration Operations

The International Space Exploration Coordination Group (ISECG) Global Exploration Roadmap (GER) provides a broad international context for understanding how robotic missions and robotic assets can enable future human exploration of multiple destinations. This presentation will provide a brief high-level review of the GER with a focus on key robotic missions and robotic assets that can provide enabling technology advancements and that also raise interesting operational challenges in both the near-term and long-term. The GER presently features a variety of robotic missions and robotic assets that can provide important technology advancements as well as operational challenges and improvements, in areas ranging from: (a) leveraging the International Space Station, (b) planetary science robotic missions to potential human destinations, (c) micro-g body proximity operations (e.g. asteroids), (d) autonomous operations, (e) high and low-latency telerobotics, (f) human assisted sample return, and (g) contamination control. This presentation will highlight operational and technology challenges in these areas that have feed forward implications for human exploration.

telerobotics↗

NASA NTRS2017

Oxygen Isotope Ratios of Magnetite in CI-Like Clasts from a Polymict Ureilite

Polymict ureilites contain a variety of Less than or equal to mm to cm sized non-ureilitic clasts, many of which can be identifed as chondritic and achondritic meteorite types. Among them, dark clasts have been observed in polymict ureilites that are similar to CI chondrites in mineralogy, containing phyllosilicates, magnetite, sulfide and carbonates. Bulk oxygen isotope analyses of a dark clast in Nilpena plot along the CCAM line and above the terrestrial fractionation line, on the O-poor extension of the main group ureilite trend and clearly different from bulk CI chondrites. One possible origins of such dark clast is that they represent aqueously altered precursors of ureilite parent body (UPB) that were preserved on the cold surface of the UPB. Oxygen isotope analyses of dark clasts are key to better understanding their origins. Oxygen isotope ratios of magnetite are of special interest because they reflect the compositions of the fluids in asteroidal bodies. In primitive chondrites, Delta O (= Delta O - 0.52× Delta O) values of magnetites are always higher than those of the bulk meteorites and represent minimum Delta O values of the initial O-poor aqueous fluids in the parent body. Previous SIMS analyses on magnetite and fayalite in dark clasts from the DaG 319 polymict ureilite were analytically difficult due to small grain sizes, though data indicated positive Delta O values of 3-4 per mille, higher than that of the dark clast in Nilpena (1.49per mille).

Kita, N. T.↗

NASA NTRS2020

A Systems Analysis Approach to Understanding the Physiological Adaptation to Spaceflight

This book is a summary of interdisciplinary research (physiology, space medicine, engineering, computer science, mathematics) that spans two decades (1972-1992). The research was an attempt to use systems analysis, mathematical modeling, computer simulations, and database systems to integrate the biomedical spaceflight data that was being collected during this period. The goal of the effort was to achieve a better understanding of the human physiological response to short-term and long-term space travel. The activity was primarily devoted to analyzing the biomedical results of Skylab (1973-74), a series of three space missions which is still ranked as the most comprehensive of all long-term biomedical space studies to date. This work was begun as a coordinated effort between the National Aeronautics and Space Administration (Johnson Space Center) and the General Electric Company’s Space Division (Houston, TX). It was the intent that this multidisciplined, integrative approach could reveal aspects of the then-new science of microgravity adaptation that were not obvious by adhering to the traditional methodology of examining each organ system in isolation. Some joint work with the Russians, including the Apollo-Soyez test project and a joint bedrest study was also supported during this period. In the 1980’s the systems analysis group’s effort was redirected to support the science management of human and animal experiments on the Space Shuttle. A few examples from this era are also included in the book. Parts of this work have been published elsewhere, presented at technical meetings, and documented in reports with limited distribution. These publications will be referenced throughout the text and the interested reader is advised to use these as resource material where additional details are desired. The intent of this book is not to reproduce these documents but rather to present a coherent view of the integrative analysis under one cover. This volume contains the first detailed publication (other than in internal reports) of an extensive metabolic balance analysis of Skylab data, the development and validation of the “Whole-Body Algorithm,” and simulation studies of diverse hypogravic environments. An analysis of cardiovascular deconditioning and a description of the calcium regulatory model are also new. A long period has passed between the completion of the main body of work represented in this book and its publication in this form. It was inevitable that new research efforts would lead to developments related to the spaceflight problems addressed and thereby make some of our biomedical conclusions obsolete. Although in some cases reference to more recent work have been included, for the most part this book should be considered an historical summary demonstrating the approach and utility of systems analysis and computer modeling in the NASA Life Sciences program at the time the studies were conducted.

Leonard, Joel I.↗

DOE OSTI2014

Current Trends in the Detection of Sociocultural Signatures: Data-Driven Models

The harvesting of behavioral data and their analysis through evidence-based reasoning enable the detection of sociocultural signatures in their context to support situation awareness and decision making. Harvested data are used as training materials from which to infer computational models of sociocultural behaviors or calibrate parameters for such models. Harvested data also serve as evidence input that the models use to provide insights about observed and future behaviors for targets of interest. The harvested data is often the result of assembling diverse data types and aggregating them into a form suitable for analysis. Data need to be analyzed to bring out the categories of content that are relevant to the domain being addressed in order to train or run a model. If, for example, we are modeling the intent of a group to engage in violent behavior using messages that the group has broadcasted, then these messages need to be processed to extract and measure indicators of violent intent. The extracted indicators and the associated measurements (e.g. rates or counts of occurrence) can then be used to train/calibrate and run computational models that assess the propensity for violence expressed in the source message. Ubiquitous access to the Internet, mobile telephony and technologies such as digital photography and digital video have enabled social media application platforms such as Facebook, YouTube, and Twitter that are altering the nature of human social interaction. The fast increasing pace of online social interaction introduces new challenges and opportunities for gathering sociocultural data. Challenges include the development of harvesting and processing techniques tailored to new data environments and formats (e.g. Twitter, Facebook), the integration of social media content with traditional media content, and the protection of personal privacy. As these and other challenges are addressed, a new wealth of behavioral data and data analysis methods becomes available that are shaping social computing as a strongly data-driven experimental discipline with an increasingly stronger impact on the decision-making process of groups and individuals alike. In this chapter, we review current advances and trends in the detection of sociocultural signatures. Specific embodiments of the issues discussed are provided with respect to the assessment of violent intent and sociopolitical contention. We begin by reviewing current approaches to the detection of sociocultural signatures in these domains. Next, we turn to the review of novel data harvesting methods for social media content. Finally, we discuss the application of sociocultural models to social media content, and conclude by commenting on current challenges and future developments.

Sanfilippo, Antonio P.↗

DOE OSTI2013

Synthesis, crystal structure and properties of [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} with mixed-valent Ge centers

One new manganese thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} (dien=diethylenetriamine), was prepared under mild solvothermal conditions and structurally and spectroscopically characterized. The title compound crystallizes in the orthorhombic system, chiral space group P2{sub 1}2{sub 1}2{sub 1} (no. 19) with a=9.113(4) Å, b=12.475(5) Å, c=17.077(7) Å, V=1941.5(15) Å{sup 3} and Z=4. Its structure features a three-dimensional (3D) network composed of a one-dimensional (1D) [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain and a [(dien){sub 2}Mn]{sup 2+} complex interconnected via various hydrogen bonds. The most interesting structural feature of the compound is the presence of two different oxidation states of germanium centers in the 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain, which is also supported by the result of X-ray photoelectron spectroscopy measurement. The optical property of the title compound has also been studied by UV–vis spectra. - Graphical abstract: One new thiogermanate, [(dien){sub 2}Mn]Ge{sub 2}S{sub 4}, contains a one-dimensional [Ge{sub 2}S{sub 4}]{sup 2−} anionic chain with two different oxidation states of germanium centers. Display Omitted - Highlights: • One new manganese thiogermanate [(dien){sub 2}Mn]Ge{sub 2}S{sub 4} was prepared. • The compound features 1D [Ge{sub 2}S{sub 4}]{sup 2−} chain composed of [Ge{sup II}S{sub 4}] and [Ge{sup IV}S{sub 4}] tetrahedra. • The first example of inorganic–organic hybrid thiogermanates with mixed valent Ge centers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2018

Two diverse models of embedding class one

Highlights: •The embedding of curved spacetime in higher-dimensional flat spacetime is discussed. •The focus is on two diverse models of embedding class one. •The first model is a complete wormhole solution including the junction conditions. •The second is a new model to explain the flat galactic rotation curves without the need for dark matter. -- Abstract: Embedding theorems have continued to be a topic of interest in the general theory of relativity since these help connect the classical theory to higher-dimensional manifolds. This paper deals with spacetimes of embedding class one, i.e., spacetimes that can be embedded in a five-dimensional flat spacetime. These ideas are applied to two diverse models, a complete solution for a charged wormhole admitting a one-parameter group of conformal motions and a new model to explain the flat rotation curves in spiral galaxies without the need for dark matter.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2023

Origin of hydroxyl pair formation on reduced anatase TiO 2 (101)

The interaction of water with metal oxide surfaces is of key importance to several research fields and applications. Because of its ability to photo-catalyze water splitting, reducible anatase TiO 2 (a-TiO 2 ) is of particular interest. Here, we combine experiments and theory to study the dissociation of water on bulk-reduced a-TiO 2 (101). Following large water exposures at room temperature, point-like protrusions appear on the a-TiO 2 (101) surface, as shown by scanning tunneling microscopy (STM). These protrusions originate from hydroxyl pairs, consisting of terminal and bridging OH groups, OH t /OH b , as revealed by infrared reflection absorption spectroscopy (IRRAS) and valence band experiments. Utilizing density functional theory (DFT) calculations, we offer a comprehensive model of the water/a-TiO 2 (101) interaction. In conclusion, this model also explains why the hydroxyl pairs are thermally stable up to ~480 K.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗