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At least 379 records · Page 21

Engineering the Big Chill: The story of JLab’s Central Helium Liquefier

This article tells the story of the Central Helium Liquefier (CHL) at the Thomas Jefferson National Accelerator Facility (JLab), one of the US National Laboratories. JLab’s successful superconducting radio frequency accelerator was only possible because a group of JLab engineers successfully tackled a complex of difficulties to build a cryogenic system that included the CHL, a task that required advancing the frontier of cryogenic technology. Ultimately, these cryogenic advances were applied far beyond JLab to the benefit of cutting-edge programs at other US national laboratories (Oak Ridge, Brookhaven, and the Facility for Rare Isotope Beams at MSU) as well as NASA. In addition, this innovation story dramatizes the sort of engineer-driven technological problem solving that allows the successful launch and operation of experimental projects. Along the way, the CHL story also provides an important addition to our understanding of the role played by engineers and industry in creating knowledge at physics laboratories.

43 PARTICLE ACCELERATORS↗

Current Status of Interventional Radiology Treatment of Infrapopliteal Arterial Disease

Treatment of infrapopliteal arteries has developed to a standard technique during the past two decades. With the introduction of innovative devices, a variety of techniques has been created and is still under investigation. Treatment options range from plain balloon angioplasty (POBA), all sorts of stent applications, such as bare metal, balloon expanding, self-expanding, coated and drug-eluting stents, and bio-absorbable stents, to latest developments, such as drug-eluting balloons. Regarding the scientific background, several prospective, randomized studies with relevant numbers of patients have been (or will be) published that are Level I evidence. In contrast to older studies, which primarily were based mostly on numeric parameters, such as diameters or residual stenoses, more recent study concepts focus increasingly on clinical features, such as amputation rate improvement or changes of clinical stages and quality of life standards. Although it is still not decided, which of the individual techniques might be the best one, we can definitely conclude that whatever treatment of infrapopliteal arteries will be used it is of substantial benefit for the patient. Therefore, the goal of this review is to give an overview about the current developments and techniques for the treatment of infrapopliteal arteries, to present clinical and technical results, to weigh individual techniques, and to discuss the recent developments.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Rapid systematic assessment of the detection and attribution of regional anthropogenic climate change

Despite being a well-established research field, the detection and attribution of observed climate change to anthropogenic forcing is not yet provided as a climate service. One reason for this is the lack of a methodology for performing tailored detection and attribution assessments on a rapid time scale. Here we develop such an approach, based on the translation of quantitative analysis into the “confidence” language employed in recent Assessment Reports of the Intergovernmental Panel on Climate Change. While its systematic nature necessarily ignores some nuances examined in detailed expert assessments, the approach nevertheless goes beyond most detection and attribution studies in considering contributors to building confidence such as errors in observational data products arising from sparse monitoring networks. When compared against recent expert assessments, the results of this approach closely match those of the existing assessments. Where there are small discrepancies, these variously reflect ambiguities in the details of what is being assessed, reveal nuances or limitations of the expert assessments, or indicate limitations of the accuracy of the sort of systematic approach employed here. Deployment of the method on 116 regional assessments of recent temperature and precipitation changes indicates that existing rules of thumb concerning the detectability of climate change ignore the full range of sources of uncertainty, most particularly the importance of adequate observational monitoring.

54 ENVIRONMENTAL SCIENCES↗

Ash production and dispersal from sustained low-intensity Mono-Inyo eruptions

Recent rhyolitic volcanism has demonstrated that prolonged low-intensity ash venting may accompany effusive dome formation. In this work, we examine the possibility and some consequences of episodes of extended, weak ash venting at the rhyolitic Mono-Inyo chain in Eastern California. We describe ash-filled cracks within one of the youngest domes, Panum Crater, which provide a textural record of ash venting during dome effusion. We use synchrotron-based X-ray computed tomography to characterize the particles in these tuffisites. Particle sizes in well-sorted tuffisite layers agree well with grain size distributions observed during weak ash venting at Soufrière Hills Volcano, Montserrat, and yield approximate upper and lower bounds on gas velocity and mass flux during the formation of those layers. We simulate ash dispersal with Ash3d to assess the consequences of long-lived Mono-Inyo ash venting for ash deposition and the accompanying volcanic hazards. Finally, our results highlight the sensitivity of large-scale outcomes of volcanic eruptions to small-scale processes.

54 ENVIRONMENTAL SCIENCES↗

Promising Technology for Reprocessing Complex Uranium Ores from the Elkon Deposit

The results of research on reprocessing of complex uranium ores from the Elkon deposit with recovery of uranium, gold, silver, and vanadium by methods of radiometric sorting, combining of autoclave and atmospheric leaching of ore followed by sorption and extraction recovery of valuable components, are presented. The capacity was 90 mg/g in sorption of uranium on strongly basic anionite and the uranium concentration ≤0.003 g/dm{sup 3} in sorption filtrates. The choice of eluent is determined by the formulation of the problem of obtaining the finished uranium product of the requisite form and quality. A fundamentally new composition of the extracting agent is proposed for direct extraction of uranium from nitrate-containing solutions. An iron-vanadium concentrate with vanadium and iron content 2.58 and 22.8%, respectively, suitable for subsequent reprocessing, was obtained. The anionite PuroGold S-992 is recommended for recovery of gold and silver. The gold and silver concentrations in the commercial desorbate were 270 and 380 mg/dm{sup 3}, respectively; a gold-containing concentrate was obtained.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Obtaining Diluent for High-Enrichment Uranium Hexafluoride in Two- and Three-Stage Cascades

The production of diluent for high-enrichment uranium in a cascade from waste uranium hexafluoride with unknown {sup 234}U content is examined. To secure high-quality diluent and reduce separative work consumption, it is proposed that the diluent be produced in two stages with sorting and extraction of the best intermediate produced in terms of {sup 234}U concentration after the first stage. The worst intermediate products are best used at the second stage to obtain low-enrichment uranium hexafluoride satisfying ASTM C 996-15 specifications. In addition, the obtained new wastes can be used in a third stage to produce diluent with low {sup 234}U concentration.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

A Scalable Space-Time Domain Decomposition Approach for Solving Large Scale Nonlinear Regularized Inverse Ill Posed Problems in 4D Variational Data Assimilation

We address the development of innovative algorithms designed to solve the strong-constraint Four Dimensional Variational Data Assimilation (4DVar DA) problems in large scale applications. We present a space-time decomposition approach which employs the whole domain decomposition, i.e. both along the spacial and temporal direction in the overlapping case, and the partitioning of both the solution and the operator. Starting from the global functional defined on the entire domain, we get to a sort of regularized local functionals on the set of sub domains providing the order reduction of both the predictive and the Data Assimilation models. The algorithm convergence is developed. Performance in terms of reduction of time complexity and algorithmic scalability is discussed on the Shallow Water Equations on the sphere. The number of state variables in the model, the number of observations in an assimilation cycle, as well as numerical parameters as the discretization step in time and in space domain are defined on the basis of discretization grid used by data available at repository Ocean Synthesis/Reanalysis Directory of Hamburg University.

97 MATHEMATICS AND COMPUTING↗

A Novel RFID-Based Strain Sensor for Wireless Structural Health Monitoring

Conventional tools for deformation measurement are widely used for structural health monitoring—i.e. strain gauges and fiber optic sensors—due to their relative low cost and efficiency. However, these techniques still present some drawbacks particularly in limited access locations, since their usage requires some sort of cabling or battery-driven electronics. Thus, in a few situations there may be room for new technologies for deformation monitoring of structures. One of the options are passive radio frequency identification (RFID)-based sensors. In synthesis, like conventional methods, these sensors are attached to the surface a test-piece, but are then remotely interrogated and powered by a transmitter. The solidarity of the sensor to the underlying material means that the detected signal is modified in a way that can be correlated to sample strain in a given direction. This paper encompasses the project of a wireless deformation sensor based on an inverted-F antenna focusing on its miniaturization and performance optimization. For this purpose, such an antenna was designed with the help of finite element modelling tools for operation on a 2.0 mm-thick aluminium sheet, and then experimentally validated through static loading tests. Finally, even though sensors of this kind are still in early developments, results show that RFID sensors represents a promising method for remote deformation assessment in components.

42 ENGINEERING↗

Degradability Characterization of EPDM/IIR Blends by γ-irradiation

In this paper the modifications induced in butyl rubbers (pristine, chlorinated and brominated sorts) by γ-irradiation are investigated by swelling, chemiluminescence and FT-IR. The susceptibility of butyl rubbers for the generation of radicals orders their stabilities in the following sequence: IIR > IIR—Cl > IIR—Br. The incorporation of butyl rubbers into ethylene-propylene terpolymer matrix brings about increased densities of radicals initiating modifications in the oxidation state in respect with recombination, which are intensified as the processing dose increases. Based on the variation of carbonyl and hydroxyl indices the favorable route for the recycling EPDM based formulations would be suggested in this study. The chemiluminescence spectra proving the formation of peroxyl radicals at about 100 °C prove their availability as reclaiming solutions. IIR—Br is the recommendable butyl rubber for the recovery procedure by association with EPDM. The suitability of IIRs for recycling purposes is analyzed by the variation in their crosslink densities, free volumes and swelling degrees. The crosslinking behavior of stabilized EPDM/IIR blends that runs to the improvement of durability is depicted by Charlesby–Pinner representation, which involves the different simultaneous contribution of scission and crosslinking processes.

36 MATERIALS SCIENCE↗

Giving rise to a set of fractional dipoles using spiral hyperbolic zone plate

We demonstrate a structured spiral hyperbolic zone plate which is able to generate a set of fractional vortex dipoles. The element is created by superimposition of two perpendicular hyperbolic zone plates in horizontal and vertical directions and its phase structure is then modified by adding an azimuthal characteristics factor. By setting different parameters when designing the element, characteristics of the generated FVDs will be changed. We then observed FVDs with different orders and topological charges rotate around the propagation axes upon propagation. This technique provides the possibility to generate multiple FVDs, and can be used in domains where sorting and guiding of small particles are of high interest such as optical tweezers and particle trapping configurations. Numerical and experimental results verify the superior features of SHFZP.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Trends in Light and Temperature Sensitivity Recommendations among Licensed Biotechnology Drug Products

Inherent structural and functional properties of biotechnology-derived therapeutic biologics make them susceptible to light- and temperature-induced degradation and consequently can influence their quality. Photosensitivity of therapeutic proteins continues to be examined, but the commonalities and trends of storage conditions and information about light and temperature sensitivity among currently licensed therapeutic proteins has not been previously surveyed. Using a comprehensive and relational database approach, we conducted a scientific survey of all licensed biotechnology-derived drug products with the goal of providing evidence-based information about recommended storage conditions of formulations sorted by light- and temperature-related attributes as described for each product at licensure. We report the prevalence of indications for light and temperature sensitivity in formulations categorized by their presentation type, number of doses, container type, dosage form and active molecule type. We also report the storage temperature range across formulations and diluents for reconstitution and dilution. Formulations with excipients that potentially facilitate light-induced and thermal degradation were also noted. The result of our analysis indicates that light and temperature sensitivity are prevalent across therapeutic protein formulations. However, when a formulation is reconstituted or diluted, both light and temperature sensitivity are less clear. In addition, light and temperature sensitivity are more well defined in liquid formulations than lyophilized powder formulations, and more well defined in products manufactured in autoinjectors, prefilled-syringes, and pens than products in vials. Overall, our report provides a data-driven summary of storage conditions among therapeutic protein formulations to support the development of future biologic drug products.

60 APPLIED LIFE SCIENCES↗

Initial Conditions of Planet Formation: Time Constraints from Small Bodies and the Lifetime of Reservoirs in the Solar Protoplanetary Disk

This review explores the timescales of the initial phase of planet formation, from nebular dust (CAIs and chondrules) to planetesimal accretion and differentiation, using evidence from meteorite research. Aluminium-Mg systematics of CAIs indicate either an extended period of CAI formation (∼0.3 Ma) or an initial 26 Al heterogeneity, with evidence supporting a homogeneous 26 Al abundance in the protoplanetary disk. Thermal and aqueous alteration on the parent body can disturb the U-Pb and Al-Mg chronometers in chondrules. Focusing on relatively robust isochron data from plagioclase of pristine (types ≤3.05) chondrites indicates a shift in chondrule formation locations, moving from the inner to the outer disk over time. Ages of basaltic achondrites show that silicate differentiation on small bodies was well underway within the first few million years (Ma) of our solar system. Their age record, however, reveals inconsistencies between different chronometers, partly caused by (i) secondary disturbances due to thermal metamorphism, aqueous alteration, or impacts, (ii) the presence of xenolithic minerals, and (iii) potentially variable initial 26 Al abundances due to disturbances at the mineral scale. Nucleosynthetic isotope data indicate that parent bodies of iron and stony meteorites formed in two distinct regions within the protoplanetary disk: the inner, non-carbonaceous (NC) and the outer, carbonaceous (CC) region. Based on Hf-W chronometry it has been demonstrated that NC and CC parent bodies of magmatic iron meteorites segregated their cores within ∼1–3 Ma after CAI formation, implying that parent body accretion occurred within <1 Ma in both reservoirs. Combining accretion ages with nucleosynthetic data further reveals that, at first order, NC and CC reservoirs in the solar protoplanetary disk were established within 1 Ma and existed over several Ma with limited exchange between them. In the CR chondrite accretion region of the disk, planetary bodies formed over at least 3 Ma, while in most other regions, formation spanned at least 1 Ma, with minimal changes in nucleosynthetic isotope compositions. Aerodynamical size sorting of dust likely introduced or amplified some of these variations.

26Al distribution↗

Microsegregation Measurement: Methods and Applications

Microsegregation is chemical variation at the microstructural level in a solidified ingot, which can cause undesirable effects on material properties. Its formation is driven by different levels of solute elemental solubility between solid and liquid phases, resulting in solute buildup or depletion in the liquid phase during solidification. Characterization of microsegregation can be essential for understanding its formation and removing it through heat treatment. Measurement is frequently carried out via scanning electron microscope (SEM), though metallographic analysis, mechanical testing and optical radiography have been used. SEM analysis can consist of point measurements on single dendrites, line scans across or along dendrites, elemental maps, and extended line-based or grid-based analyses extending over many dendrites, which can generate large amounts of data. Line-based or grid-based data can be analyzed using scatterplots of element concentrations to visualize segregation behavior and sorting/ranking of data by a single element or a combination of elements, to give compositional profiles as a function of extent of solidification. For both qualitative and quantitative analyses, effects of phase transformations and secondary phases need to be considered as well as sorting of measurement errors when generating compositional profiles. Applications of analysis include determination of partition ratios, examination of solute–element interactions, determination of effects of cooling rate and back diffusion, applications to freckling studies, validations of modeling, and development of heat-treatment profiles.

36 MATERIALS SCIENCE↗

Experimental Investigations for Optimizing the Extrusion Parameters on FDM PLA Printed Parts

Fused deposition modeling (FDM) has become one of the most extensively used additive manufacturing technologies in recent years because of its wide adaptability, simple mechanism and low cost. It is difficult, however, to achieve an equitable trade-off among mechanical properties, surface finish quality and production time, which is an area seldom explored. This paper concentrates on the optimization of the parameters to achieve higher tensile strength and lower surface roughness with less build time during the FDM process based on central composite design for the tensile specimen forming process. The effects of five extrusion parameters (nozzle diameter, liquefier temperature, extrusion velocity, filling velocity and layer thickness) on the three outputs of tensile strength (TS), surface roughness (SR) and build time (BT) are investigated. Response surface methodology combined with nondominated sorting genetic algorithm II is developed to optimize the process parameters to achieve the maximum TS, minimum SR and BT, as verified by subsequent experiments. The predicted results are found to be very close to the experimental data, illustrating that the presented approach in this paper is effective for improving mechanical properties, surface finish and efficiency of the FDM process.

36 MATERIALS SCIENCE↗

An Economic Model and Experiments to Understand Aluminum-Cerium Alloy Recycling

We provide an economic model to understand the impact of adoption, sorting and pricing of scrap on the recycling of a new aluminum-cerium (AlCe) alloy for use in engine blocks in the automobile industry. The goal of the laboratory portion of this study is to investigate possible effects of cerium contamination on well-established aluminum recycling streams. Here, our methodology includes three components: (1) focused data gathering from industry supply chain participants, (2) experimental data through laboratory experiments to understand the impact of cerium on existing alloys and (3) an economic model to understand pricing incentives on a recycler’s separation of AlCe engine blocks.

36 MATERIALS SCIENCE↗

Group purchasing organization design: a clustering approach

Supply chain management is monitoring of activities involved in supply chain, for integrating and coordinating between suppliers, manufacturing, inventory and transportation both within and among members. The ultimate aim of supply chains is to reduce costs and increase market coverage. Procuring and purchasing requested items in a timely manner are the two most important issues for supply chain stockholders. Group purchasing is one of the purchasing strategies in supply chains. It offers great potential by ordering large volumes to decrease expenses which can increase services to customers. A clustering optimization approach is employed to model group purchasing for a set of pharmacies in the field of healthcare. The proposed model determines a cooperation strategy based on factors such as distance between pharmacies and procurement expenditure in this network. Moreover, the proposed multi-objective group purchasing model is optimized using both goal programming and non-dominated sorting genetic algorithm. To illustrate the application of the proposed model, designing a purchasing group organization for Chalus city pharmacies is investigated. Purchasing groups are established in the way that sum of pharmacies ordering quantity has been located in the second or the third level of discount rate. Thus, the results show that GPOs can take the advantage of this cooperation.

97 MATHEMATICS AND COMPUTING↗

Enhancement of a Process Flowsheet for Recovering and Concentrating Critical Materials from Bituminous Coal Sources

Recovery of rare earth elements (REE) from coal-related resources has recently received significant interest due to supply concerns and their key roles in critical industries and defense-related technologies. In this study, an integrated flowsheet consisting of sorting, crushing/grinding, physical separation, acid leaching, solvent extraction, and selective precipitation was designed to achieve continuous production of rare earth products from various coal-related resources such as coarse refuse and acid mine drainage. A pilot plant was constructed that enabled continuous testing of the circuitry on a range of different coal-based feedstocks. Despite achieving significant success in producing high-grade rare earth oxide products, low REE recovery values and high operational costs necessitated a re-evaluation of the process flowsheet. This article describes the circuitry improvements that were based on both laboratory and pilot plant test results. Roasting as a pre-leach treatment was found to significantly improve the leaching rate and overall REE recovery values. After roasting West Kentucky No. 13 and Fire Clay coal refuse materials at 600 °C, REE recovery increased by 60 and 40 absolute percentage points, respectively. Rare earth concentration in the pregnant leachate solution (PLS) was increased to around 700 ppm prior to solvent extraction using a staged precipitation method. REEs in the precipitate were re-dissolved, purified, and extracted from the PLS using solvent extraction and selective precipitation to values of around 80%. As a result of the improvements, chemical consumption in the acid leaching and solvent extraction processes was significantly reduced. A techno-economical assessment of the improved flowsheet indicated significant commercialization potential.

01 COAL, LIGNITE, AND PEAT↗