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At least 433 records · Page 24

Gas-Phase Formation of 1,3,5,7-Cyclooctatetraene (C 8 H 8 ) through Ring Expansion via the Aromatic 1,3,5-Cyclooctatrien-7-yl Radical (C 8 H 9 • ) Transient

Gas-phase 1,3,5,7-cyclooctatetraene (C 8 H 8 ) and triplet aromatic 1,3,5,7-cyclooctatetraene (C 8 H 8 ) were formed for the first time through the bimolecular methylidyne radicals (CH) - 1,3,5-cycloheptatriene (C 7 H 8 ) reactions under single collision conditions on the doublet surface. The reaction involves methylidyne radical addition to the olefinic pi electron system of 1,3,5-cycloheptatriene followed by isomerization and ring expansion to aromatic 1,3,5-cyclooctatrien-7-yl radical (C 8 H 9 •). The chemically activated doublet radical intermediate undergoes unimolecular decomposition to 1,3,5,7-cyclooctatetraene. Substituted 1,3,5,7-cyclooctatetraene molecules can be prepared in the gas phase with hydrogen atom(s) in the 1,3,5-cycloheptatriene reactant being replaced by organic side groups. Furthermore, these findings are also of potential interest to organometallic chemists by expanding the synthesis of exotic transition metal complexes incorporating substituted 1,3,5,7-cyclooctatetraene dianion (C 8 H 8 2- ) ligands and to untangle the unimolecular decomposition of chemically activated and substituted 1,3,5-cyclooctatrien-7-yl radical eventually gaining a fundamental insight of their bonding chemistry, electronic structures, and stabilities.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Magnetic fields and extraordinarily bright radio emission in the X-ray faint galaxy group MRC 0116 + 111

ABSTRACT MRC 0116 + 111 is a nearby (z = 0.132) poor galaxy group, which was previously known for exhibiting a bright diffuse radio emission with no central point-like source, presumably related to a past activity of the active galactic nucleus (AGN) in its central cD galaxy. Here, we present an X-ray observation (∼30 ks of cleaned XMM–Newton/EPIC exposure) of this system, allowing us for the first time a detailed comparison between the thermal and non-thermal components of its intragroup medium (IGrM). Remarkably, we find that the radio-to-X-ray luminosity ratio is among the highest ever observed for a diffuse extragalactic source so far, while the extent of the observed radio emission is about three times larger than its observed soft X-ray emission. Although powerful AGN activity may have disturbed the dynamics of the thermal IGrM in the form of turbulence, possibly re-energizing part of the relativistic electron population, the gas properties lie within the LX–T scaling relation established previously for other groups. The upper limit we find for the non-thermal inverse-Compton X-ray emission translates into a surprisingly high lower limit for the volume-averaged magnetic field of the group (≥4.3 $\mu$G). Finally, we discuss some interesting properties of a distant (z ≃ 0.525) galaxy cluster serendipitously discovered in our EPIC field of view.

79 ASTRONOMY AND ASTROPHYSICS↗

Preface for the special collection commemorating the career of Pat Thiel

This Special Collection in the Journal of Vacuum Science and Technology A (JVST A) has been compiled to commemorate the career of Professor Patricia (Pat) Thiel as a scientific leader in the international surface science community. Pat passed away in September 2020 due to breast cancer. This Collection includes 26 articles from colleagues, collaborators, and former Thiel group members. The topics overlap Pat’s scientific interests and advances in areas that include chemisorption, reconstruction, and complex formation on metal surfaces; submonolayer nucleation and growth and kinetic roughening of epitaxial thin films; coarsening of surface nanostructures; intercalation; surface phenomena for intermetallics including quasicrystals; and atomic-scale friction. We wish to thank the authors for their contributions towards producing this impressive Special Collection.

99 GENERAL AND MISCELLANEOUS↗

Ring Walking/Oxidative Addition Reactions for the Controlled Synthesis of Conjugated Polymers

Power conversion efficiencies of plastic solar cells depend strongly on the molecular weight characteristics of the semiconducting polymers used for their fabrication. The synthesis of these materials typically relies on transition metal mediated catalytic reactions. In many instances, the ideal structures cannot be attained because of deficiencies in these reactions, particularly when it comes to being able to achieve high number average molecular weights and narrow molecular weight distributions. Another important conjugated polymer structure of interest is one in which a single functional group is attached at the end group of the chain. Such systems would be ideal for modifying surface properties at interfaces and for labeling biomolecular probes used in fluorescent biosensors. To respond to the challenges above, our efforts have centered on the design of homogenous transition metal complexes that are easy to prepare and effective in carrying out living, or quasi-living, condensative chain polymerization reactions. The key mechanistic challenge for the success of this reaction is to force the insertion of one monomer unit at a time via a process that involves migration of the transition metal-containing fragment to one terminus of the polymer chain. Chain growth characteristics are therefore favored when the metal does not dissociate from the newly formed reductive elimination product. We have proposed that dissociation is disfavored by the formation of a -complex, in which the metal can sample various locations of the electronically delocalized framework, a process that we term ring-walking , and find the functionality where oxidative addition takes place. Success has been achieved in the nickel-mediated cross coupling reaction of Grignard reagents with aromatic halides by using bromo[1,2-bis(diphenylphosphino)ethane]phenylnickel. This reagent can yield poly(thiophene)s (one of the most widely used type of polymer in plastic solar cells) with excellent stereoregularity and molecular weight distributions with polydispersities that are consistent with a living polymerization sequence. Another important objective of this program concerned the use of these new catalysts and improved mechanistic insight for the synthesis of specific polymeric materials with prespecified properties.

14 SOLAR ENERGY↗

Development of High-Order Accurate Interface Tracking Algorithms and Improved Constitutive Models for Problems in Continuum Mechanics with Applications to Jetting (Final Report)

Much of the work conducted under the auspices of DE-FG02-03ER25579 was characterized by an exceptionally close collaboration with researchers at the Lawrence Berkeley National Laboratory (LBNL). For example, Andy Nonaka, one of Professor Miller's graduate students in the Department of Applied Science at U. C. Davis (UCD) wrote his PhD thesis in an area of interest to researchers in the Applied Numerical Algorithms Group (ANAG), which is a part of the National Energy Research Supercomputer Center (NERSC) at LBNL.

97 MATHEMATICS AND COMPUTING↗

Deletion of the EP402R Gene from the Genome of African Swine Fever Vaccine Strain ASFV-G-ΔI177L Provides the Potential Capability of Differentiating between Infected and Vaccinated Animals

The African swine fever virus (ASFV) mutant ASFV-G-ΔI177L is a safe and efficacious vaccine which induces protection against the challenge of its parental virus, the Georgia 2010 isolate. Although a genetic DIVA (differentiation between infected and vaccinated animals) assay has been developed for this vaccine, still there is not a serological DIVA test for differentiating between animals vaccinated with ASFV-G-ΔI177L and those infected with wild-type viruses. In this report, we describe the development of the ASFV-G-ΔI177L mutant having deleted the EP402R gene, which encodes for the viral protein responsible for mediating the hemadsorption of swine erythrocytes. The resulting virus, ASFV-G-ΔI177L/ΔEP402R, does not have a decreased ability to replicates in swine macrophages when compared with the parental ASFV-G-ΔI177L. Domestic pigs intramuscularly (IM) inoculated with either 10 2 or 10 6 HAD 50 of ASFV-G-ΔI177L/ΔEP402R remained clinically normal, when compared with a group of mock-vaccinated animals, indicating the absence of residual virulence. Interestingly, an infectious virus could not be detected in the blood samples of the ASFV-G-ΔI177L/ΔEP402R-inoculated animals in either group at any of the time points tested. Furthermore, while all of the mock-inoculated animals presented a quick and lethal clinical form of ASF after the intramuscular inoculation challenge with 10 2 HAD 50 of highly virulent parental field isolate Georgia 2010 (ASFV-G), all of the ASFV-G-ΔI177L/ΔEP402R-inoculated animals were protected, remaining clinically normal until the end of the observational period. Most of the ASFV-G-ΔI177L/ΔEP402R-inoculated pigs developed strong virus-specific antibody responses against viral antigens, reaching maximum levels at 28 days post inoculation. Importantly, all of the sera collected at that time point in the ASFV-G-ΔI177L/ΔEP402R-inoculated pigs did not react in a direct ELISA coated with the recombinant EP402R protein. Conversely, the EP402R protein was readily recognized by the pool of sera from the animals immunized with recombinant live attenuated vaccine candidates ASFV-G-ΔI177L, ASFV-G-ΔMGF, or ASFV-G-Δ9GL/ΔUK. Therefore, ASFV-G-ΔI177L/ΔEP402R is a novel, safe and efficacious candidate with potential to be used as an antigenically DIVA vaccine.

59 BASIC BIOLOGICAL SCIENCES↗

Some considerations in low-cost image processing on a university main frame: The Penn State (ORSER) experience

The ORSER System as implemented on the Penn State University Computation Center's IBM main frame is an exceptionally useful mechanism for instructing the present and future remote sensing community in the theory and practice of automated analysis of digitized data. From its beginning, the system was used as the hands-on back-bone of a graduate level "Multispectral Remote Sensing" one-term course taught annually in the School of Forest Resources. It was also used at the end of a senior-level undergraduate "Introduction to Remote Sensing" course, and in teaching a variety of short courses, ranging in length from a few days for small groups of remote sensing consultants with specific application interests, to a 2-week course oganized by NASA for regional and urban planners who had little or no previous exposure to remote sensing. Because of its modular construction, the ORSER is suitable for all classes of remote sensing users. Although in a beginning course only 6 to 10 of the programs are generally used, the researcher has a set of about 35 programs available for his analyses.

Turner, B. J.↗

Theory and modeling group

The primary purpose of the Theory and Modeling Group meeting was to identify scientists engaged or interested in theoretical work pertinent to the Max '91 program, and to encourage theorists to pursue modeling which is directly relevant to data which can be expected to result from the program. A list of participants and their institutions is presented. Two solar flare paradigms were discussed during the meeting -- the importance of magnetic reconnection in flares and the applicability of numerical simulation results to solar flare studies.

Holman, Gordon D.↗

Digital mammography, cancer screening: Factors important for image compression

The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers.

Clarke, Laurence P.↗

The 1993/1994 NASA Graduate Student Researchers Program

The NASA Graduate Student Researchers Program (GSRP) attempts to reach a culturally diverse group of promising U.S. graduate students whose research interests are compatible with NASA's programs in space science and aerospace technology. Each year we select approximately 100 new awardees based on competitive evaluation of their academic qualifications, their proposed research plan and/or plan of study, and their planned utilization of NASA research facilities. Fellowships of up to $22,000 are awarded for one year and are renewable, based on satisfactory progress, for a total of three years. Approximately 300 graduate students are, thus, supported by this program at any one time. Students may apply any time during their graduate career or prior to receiving their baccalaureate degree. An applicant must be sponsored by his/her graduate department chair or faculty advisor; this book discusses the GSRP in great detail.

Source record↗

New technology and regional studies in human ecology: A Papua New Guinea example

Two key issues in using technologies such as digital image processing and geographic information systems are a conceptually and methodologically valid research design and the exploitation of varied sources of data. With this realized, the new technologies offer anthropologists the opportunity to test hypotheses about spatial and temporal variations in the features of interest within a regionally coherent mosaic of social groups and landscapes. Current research on the Mountain OK of Papua New Guinea is described with reference to these issues.

Morren, George E. B., Jr.↗

Interactions between spacecraft and their environments

Spacecraft inevitably interact with their environments. Besides the interactions one immediately thinks of in space (zero-g, solar heating, atmospheric drag, expansion into vacuum conditions, etc.) other interactions are also important. Those of interest to spacecraft designers so far may be grouped under several headings; plasma interactions and spacecraft charging, impact of debris and micrometeoroids, chemical reactions with neutral species, radiation degradation, etc. Researchers have made great progress in defining and evaluating the interactions of spacecraft with their expected ambient environments near Earth and in interplanetary space. Some of these interactions are discussed with an eye toward expanding our knowledge into new environments, such as may be found at the moon and Mars, that will interact in new and different ways with exploring spacecraft and spacefarers.

Ferguson, Dale C.↗

An On-line Technology Information System (OTIS) for Advanced Life Support

OTIS is an on-line communication platform designed for smooth flow of technology information between advanced life support (ALS) technology developers, researchers, system analysts, and managers. With pathways for efficient transfer of information, several improvements in the ALS Program will result. With OTIS, it will be possible to provide programmatic information for technology developers and researchers, technical information for analysts, and managerial decision support. OTIS is a platform that enables the effective research, development, and delivery of complex systems for life support. An electronic data collection form has been developed for the solid waste element, drafted by the Solid Waste Working Group. Forms for other elements (air revitalization, water recovery, food processing, biomass production and thermal control) will also be developed, based on lessons learned from the development of the solid waste form. All forms will be developed by consultation with other working groups, comprised of experts in the area of interest. Forms will be converted to an on-line data collection interface that technology developers will use to transfer information into OTIS. Funded technology developers will log in to OTIS annually to complete the element- specific forms for their technology. The type and amount of information requested expands as the technology readiness level (TRL) increases. The completed forms will feed into a regularly updated and maintained database that will store technology information and allow for database searching. To ensure confidentiality of proprietary information, security permissions will be customized for each user. Principal investigators of a project will be able to designate certain data as proprietary and only technical monitors of a task, ALS Management, and the principal investigator will have the ability to view this information. The typical OTIS user will be able to read all non-proprietary information about all projects.Interaction with the database will occur over encrypted connections, and data will be stored on the server in an encrypted form. Implementation of OTIS will initiate a community-accessible repository of technology development information. With OTIS, ALS element leads and managers will be able to carry out informed technology selection for programmatic decisions. OTIS will also allow analysts to make accurate evaluations of technology options. Additionally, the range and specificity of information solicited will help educate technology developers of program needs. With augmentation, OTIS reporting is capable of replacing the current fiscal year-end reporting process. Overall, the system will enable more informed R&TD decisions and more rapid attainment of ALS Program goals.

Levri, Julie A.↗

Two-photon or higher-order absorbing optical materials and methods of use

Compositions capable of simultaneous two-photon absorption and higher order absorptivities are provided. Compounds having a donor-pi-donor or acceptor-pi-acceptor structure are of particular interest, where the donor is an electron donating group, acceptor is an electron accepting group, and pi is a pi bridge linking the donor and/or acceptor groups. The pi bridge may additionally be substituted with electron donating or withdrawing groups to alter the absorptive wavelength of the structure. Also disclosed are methods of generating an excited state of such compounds through optical stimulation with light using simultaneous absorption of photons of energies individually insufficient to achieve an excited state of the compound, but capable of doing so upon simultaneous absorption of two or more such photons. Applications employing such methods are also provided, including controlled polymerization achieved through focusing of the light source(s) used.

Marder, Seth↗

A Summary of the 2023 Joint High-Speed Boundary Layer Transition Workshop

A joint workshop between the Air Force Office of Scientific Research, the Office of Naval Research, and the NASA Hypersonic Technology Project was held in June 2023 on the topic of high-speed boundary-layer transition. The purpose of this workshop was to gather subject matter experts in the areas of supersonic and hypersonic boundary-layer transition in the areas of geometries of interest, computational methods, facilities and diagnostics, flight experiments, flow control, and new approaches and to discuss the current state of the art in the field. As gaps and accomplishments were identified, roadmaps were also created to guide future investments in these areas. The top recommendations are (1) to define relevant common geometries of interest that can be worked by multiple research groups; (2) improve modeling of high-enthalpy flows involving chemistry and ablation, studies of receptivity of freestream disturbances and atmospheric particulates into the boundary layer, surface feature characterization and modeling of changes to geometry; (3) design and determine viable flow control methods; and (4) move towards incorporating boundary layer transition prediction into a standard practice for design of high-speed vehicles. To execute this last recommendation successfully, investments beyond fundamental (basic and early applied) research are needed.

boundary layer transition↗

The Emerging Issue-3 Revision of the Ccsds-123.0-B Low-Complexity Lossless and Near-Lossless Multispectral and Hyperspectral Image Compression Standard

The CCSDS-123.0-B Low-Complexity Lossless and Near-Lossless Multispectral & Hyperspectral Image Compression standard provides state-of-the-art compression for imaging spectrometer data. Issue 1 of this standard, published in 2012, provides only lossless compression capability. In 2019, Issue 2 was published, adding new features and in particular augmenting the compressor to provide also near-lossless compression, i.e., compression with a user-specified error limit in each spectral band. This presentation will describe the Issue 3 revision currently under development by the CCSDS Data Compression working group. This revision will provide region-of-interest compression capability. That is, a user-provided spatial classification map can be used to specify different data fidelity parameters in different image regions. This would, for example, allow an onboard classification algorithm to identify the most important regions of an image, or regions obscured by clouds, and adjust compression fidelity accordingly in each region to maximize value of imaging spectrometer data returned over constrained space communication links. The revision also aims to add an option that is unrelated to region-of-interest compression but can improve compression effectiveness in some cases.

CCSDS Hyperspectral↗

One System Integrated Project Team Progress in Coordinating Hanford Tank Farms and the Waste Treatment Plant

The One System Integrated Project Team (IPT) was formed at the Hanford Site in late 2011 as a way to improve coordination and itegration between the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Tank Operations Contractor (TOC) on interfaces between the two projects, and to eliminate duplication and exploit opportunities for synergy. The IPT is composed of jointly staffed groups that work on technical issues of mutal interest, front-end design and project definition, nuclear safety, plant engineering system integration, commissioning, planning and scheduling, and environmental, safety, health and quality (ESH&Q) areas. In the past year important progress has been made in a number of areas as the organization has matured and additional opportunities have been identified. Areas covered in this paper include: Support for development of the Office of Envirnmental Management (EM) framework document to progress the Office of River Protection's (ORP) River Protection Project (RPP) mission; Stewardship of the RPP flowsheet; Collaboration with Savannah River Site (SRS), Savannah River National Laboratory (SRNL), and Pacific Northwest National Laboratory (PNNL); Operations programs integration; and, Further development of the waste acceptance criteria.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

Laser-induced breakdown spectroscopy↗