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Extension of the Focusable Mass Range in Distance-of-Flight Mass Spectrometry with Multiple Detectors
Since the underlying theory of Distance-of-Flight Mass Spectrometry (DOFMS) was reported in 2007,[1] laboratory results[2, 3] have proven its practical viability. However, these previous implementations of DOFMS considered ion detection only over narrow DOF-detection windows, with 25-mm being the greatest detection length explored. These small mass windows cannot be used to evaluate how DOFMS focusing performs over greater DOF detection lengths and mass ranges. In the present study, we expand on previous studies by placing two spatially selective ion detectors along the detection plane of the DOFMS instrument. Ion signals are simultaneously collected from both DOF detectors in order to simulate DOFMS performance with a longer spatially selective ion detector.
A practical extension of the recursive multi-fidelity model for the emulation of hole closure experiments
We report in regimes of high strain rate, the strength of materials often cannot be measured directly in experiments. Instead, the strength is inferred based on an experimental observable, such as a change in shape, that is matched by simulations supported by a known strength model. In hole closure experiments, the rate and degree to which a central hole in a plate of material closes during a dynamic loading event are used to infer material strength parameters. Due to the complexity of the experiment, many computationally expensive, three-dimensional simulations are necessary to train an emulator for calibration or other analyses. These simulations can be run at multiple grid resolutions, where dense grids are slower but more accurate. In an effort to reduce the computational cost, a combination of simulations with different resolutions can be combined to develop an accurate emulator within a limited training time. We explore the novel design and construction of an appropriate functional recursive multi-fidelity emulator of a strength model for tantalum in hole closure experiments that can be applied to arbitrarily large training data. Hence, by formulating a multi-fidelity model to employ low-fidelity simulations, we were able to reduce the error of our emulator by approximately 81% with only an approximately 1.6% increase in computing resource utilization.
RDPM: An Extensible Tool for Resilience Design Patterns Modelling
Resilience to faults, errors, and failures in extreme-scale high-performance computing (HPC) systems is a critical challenge. Resilience design patterns offer a new, structured hardware and software design approach for improving resilience. While prior work focused on developing performance, reliability, and availability models for resilience design patterns, this paper extends it by providing a Resilience Design Patterns Modeling (RDPM) tool which allows (1) exploring performance, reliability, and availability of each resilience design pattern, (2) offering customization of parameters to optimize performance, reliability, and availability, and (3) allowing investigation of trade-off models for combining multiple patterns for practical resilience solutions.
Displaced vertex signatures of doubly charged scalars in the type-II seesaw and its left-right extensions
The type-II seesaw mechanism with an isospin-triplet scalar Δ L provides one of the most compelling explanations for the observed smallness of neutrino masses. The triplet contains a doubly-charged component $H^{±±}_{L}$, which dominantly decays to either same-sign dileptons or to a pair of W bosons, depending on the size of the triplet vacuum expectation value. However, there exists a range of Yukawa couplings ƒ L of the triplet to the charged leptons, wherein a relatively light $H^{±±}_{L}$ tends to be long-lived, giving rise to distinct displaced-vertex signatures at the high-energy colliders. We find that the displaced vertex signals from the leptonic decays $H^{±±}_{L} → ℓ^±_αℓ^±_β$ could probe a broad parameter space with 10 -10 ≲ |ƒ L | ≲ 10 -6 and 45.6 GeV<$M_{H^{±±}_{L}}$≲200 GeV at the high-luminosity LHC. Similar sensitivity can also be achieved at a future 1 TeV e + e - collider. The mass reach can be extended to about 500GeV at a future 100TeV proton-proton collider. Similar conclusions apply for the right-handed triplet $H^{±±}_{R}$ in the TeV-scale left-right symmetric models, which provide a natural embedding of the type-II seesaw. We show that the displaced vertex signals are largely complementary to the prompt same-sign dilepton pair searches at the LHC and the low-energy, high-intensity/precision measurements, such as neutrinoless double beta decay, charged lepton flavor violation, electron and muon anomalous magnetic moments, muonium-antimuonium oscillation and Møller scattering.
In Vitro Assessment of a New Extension Set Intended to Reduce Occupational Exposure to Antineoplastic Drugs During Hepatic Chemoembolisation
No abstract prepared.
Poleward shift and intensified variability of Kuroshio-Oyashio extension and North Pacific Transition Zone under climate change
Not provided.
Development of Technological Equipment for RBMK Service-Life Extension
This article is devoted to the solution of the now urgent problem of the aging of the RBMK-1000 graphite stack (bending of the graphite columns as a result of cracking of the graphite blocks under the action of temperature and exposure to radiation). The successful work performed by a group of specialists from the Diakont Company Group on restoring the service-life characteristics of the first two power-generating units at the Leningradskaya NPP is considered as an example. Laying bare the crux of the main stages and particulars of the technological process, considerable attention is given to the principle of operation, technical possibilities, and rigging of unique equipment produced by the Diakont. The development of a complete rigging complex for restoring the service-life characteristics of the reactor plant is given together with a detailed description of the operating principles of each type of equipment.
Sensitivity of Turbine-Height Wind Speeds to Parameters in the Planetary Boundary-Layer Parametrization Used in the Weather Research and Forecasting Model: Extension to Wintertime Conditions
This work extends the model sensitivity analysis of Yang et al. (Boundary-Layer Meteorology, 2017, Vol. 162, 117-142) to include results for February 2011, in addition to May of the same year. We investigated the sensitivity of simulated hub-height wind speeds to the selection of 26 parameters applied in the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-layer parameterization in the Weather Research and Forecasting (WRF) model, including parameters used to represent the dissipation of turbulence kinetic energy (TKE), Prandtl number (Pr), and turbulence length scales. Differences in the sensitivity of the ensemble of simulated wind speed to the various parameters can largely be explained by changes in the static stability. The largest monthly differences were found during the day, while the sensitivity to many of the parameters during the night were similar regardless of the month. This finding is consistent with an increased frequency of day-time stable conditions in February compared to May. The spatial variability of the sensitivity to TKE dissipation, Pr, and k can also be attributed to variability in the static stability across the domain at any point in time.
Improving process-based estimates of N2O emissions from soil using temporally extensive chamber techniques and stable isotopes
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Preparation of Low-Density Microcellular Foams from Recycled PET Modified by Solid State Polymerization and Chain Extension
Recycled polyethylene-terephthalate (RPET) bottle regrinds were physically foamed after two types of industrially feasible molecular weight increasing processes. Intrinsic viscosity (IV) of initial waste (0.71 dL/g) increased both after reactive extrusion carried out using a multifunctional epoxy-based chain extender (0.74 dL/g) and after solid state polycondensation (SSP) (0.78 dL/g), while capillary rheometry revealed higher degree of branching in the chain extended PET material. Despite the relatively low IV values (below 0.80 dL/g), physical foaming, a mild and cost-efficient way, was successful in both cases, uniform microcellular foam structures with void fractions ranging between 75 and 83% were achieved. During the experiments morphology change in the materials was tracked by differential scanning calorimetry (DSC) besides recording IV values. The IV drop during foaming was between 0.03 and 0.10 depending on the pre-processing technology. Structure of foams produced from the two different modified RPET materials was compared with each other based on scanning electron microscopic imaging of cryogenic fracture surfaces. The average cell diameters were measured to be 213 and 360 µm in the case of chain extended and SSP-modified materials, respectively.
Extension of the Concept of Invariance and Statistically Weakly Invariant Sets of Controllable Systems
We continue the study of statistically invariant and statistically weakly invariant sets with respect to controllable systems and differential inclusions launched by Prof. E. L. Tonkov. We examine properties of such statistical characteristics as the lower freq{sub *}(𝜑) and upper freq{sup *}(𝜑) relative frequencies of hitting a solution 𝜑(t) of a differential inclusion in a prescribed set. We obtain estimates and conditions of coincidence of these characteristics for functions whose difference tends to zero at infinity. We also present conditions of statistically weak invariance of a given set of a relatively controllable system.
Comparison of Extensive Thermal Cycling Effects on Microstructure Development in Micro-alloyed Sn-Ag-Cu Solder Joints
Pb-free solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic have promise for widespread adoption across assembly conditions and operating environments, but enhanced microstructural control is needed. Micro-alloying with elements such as Zn was demonstrated for promoting a preferred solidification path and joint microstructure earlier in simple (Cu/Cu) solder joints studies for different cooling rates. This beneficial behavior now has been verified in reworked ball grid array (BGA) joints, using dissimilar SAC305 (Sn-3.0Ag-0.5Cu, wt.%) solder paste. After industrial assembly, BGA components joined with Sn-3.5Ag-0.74Cu-0.21Zn solder were tested in thermal cycling (-55 C/+125 C) along with baseline SAC305 BGA joints beyond 3000 cycles with continuous failure monitoring. Weibull analysis of the results demonstrated that BGA components joined with SAC + Zn/SAC305 have less joint integrity than SAC305 joints, but their lifetime is sufficient for severe applications in consumer, defense, and avionics electronic product field environments. Failure analysis of the BGA joints revealed that cracking did not deviate from the typical top area (BGA component side) of each joint, in spite of different Ag3Sn blade content. Thus, SAC + Zn solder has not shown any advantage over SAC305 solder in these thermal cycling trials, but other characteristics of SAC + Zn solder may make it more attractive for use across the full range of harsh conditions of avionics or defense applications.
SCIP-Jack—a solver for STP and variants with parallelization extensions
The Steiner tree problem in graphs is a classical problem that commonly arises in practical applications as one of many variants. While often a strong relationship between different Steiner tree problem variants can be observed, solution approaches employed so far have been prevalently problem-specific. In contrast, this paper introduces a general-purpose solver that can be used to solve both the classical Steiner tree problem and many of its variants without modification. This versatility is achieved by transforming various problem variants into a general form and solving them by using a state-of-the-art MIP-framework. The result is a high-performance solver that can be employed in massively parallel environments and is capable of solving previously unsolved instances.
Quantum Chemical Mass Spectrometry: Verification and Extension of the Mobile Proton Model for Histidine
The quantum chemical mass spectrometry for materials science (QCMS{sup 2}) method is used to verify the proposed mechanism for proton transfer – the Mobile Proton Model (MPM) – by histidine for ten XHS tripeptides, based on quantum chemical calculations at the DFT/B3LYP/6-311+G* level of theory. The fragmentations of the different intermediate structures in the MPM mechanism are studied within the QCMS{sup 2} framework, and the energetics of the proposed mechanism itself and those of the fragmentations of the intermediate structures are compared, leading to the computational confirmation of the MPM. In addition, the calculations suggest that the mechanism should be extended from considering only the formation of five-membered ring intermediates to include larger-ring intermediates. .