Search

This work is devoted to study the structural and reactional properties of the prototypical example of the core–halo ( 9 Li– 11 Li) nuclei. The halo nucleus 11 Li consists of a central core of 9 Li surrounded by 2n–halo with very low separation energy ε 2 n = 378±5 KeV, reflecting the huge calculated root mean square radius value 4.11 fm. The elastic scattering potential at low and intermediate incident energies was a puzzle for decades of research on nuclear reactions. Single– and double–folding potentials describing the elastic scattering of 11 Li from the proton and 12 C, based on different effective interactions were constructed. Systematic comparison between the considered methods in terms of the renormalization coefficients is done. Based on the considered methods, the obtained potentials doesn’t need any renormalization in case of using real folding potential together with phenomenological imaginary potential and merely need renormalization almost approach unity in case of using complex folding potential to fit the total reaction cross sections and angular distributions along the measured data. Furthermore, correlations between real volume integrals and nucleon incident energies for the neutron drip–line 11 Li nucleus were proven along the whole scale of energies. [ABSTRACT FROM AUTHOR]

Thermobarometry in the Northern Snake Range metamorphic core complex (Nevada, USA) implies pre‐extensional burial of footwall rocks to 21–30 km depths, while geologic field relationships support 7–13 km pre‐extensional depths. This has fueled a 40‐year‐long debate, which has far‐reaching implications for how pressure data are interpreted in orogenic settings. Here, we test published models for deep burial by integrating regional cross‐section reconstructions with new (n = 95) and published (n = 132) peak temperature measurements, field relationships and published geophysical data. Burial of Neoproterozoic‐Cambrian metasedimentary footwall rocks to 21–30 km depths is incompatible with a regional seismic reflection cross‐section that interprets the top of Precambrian crystalline basement at 17–20 km depths. Two reconstructed cross‐sections define 42 km and 50–65 km of displacement on the master detachment fault and demonstrate that the higher displacement ranges (>66–94 km and >76–102 km, respectively) necessary to exhume rocks from 21 to 30 km depths are not possible without spatially overlapping Cambrian rocks preserved in its footwall and hanging wall. The 22°C/km average Late Cretaceous thermal gradient predicted by thermobarometry is incompatible with the 46 ± 10°C/km Late Cretaceous peak thermal gradient that we calculate down to 15–20 km pre‐extensional depths. Field relationships that rule out large‐magnitude shortening invalidate models for deep footwall burial via thrust or reverse faulting. We conclude that there is no scenario for deep burial that is compatible with structural/geophysical constraints, crustal thermal architecture, and field relationships. This necessitates a non‐lithostatic interpretation for pressures from the Northern Snake Range, similar to recent interpretations for other Cordilleran metamorphic core complexes. Key Points: Strain compatibility demonstrates that the detachment displacement necessary to exhume footwall rocks from 21 to 30 km depths is not possibleThe 22°C/km gradient predicted by thermobarometry is incompatible with the Late Cretaceous thermal gradient of 46 ± 10°C/km that we calculateA non‐lithostatic interpretation for pressure data from the Northern Snake Range is required, similar to other Cordilleran core complexes [ABSTRACT FROM AUTHOR]

Since this century, due to the dual influence of climate change and strong human activities, the water and sediment conditions en- tering the Lower Yellow River (LYR) have changed significantly. Consequently, the cross-sectional geometry of the LYR channel has been adjusted drastically under the long-term non-equilibrium sediment transport state, which affects river regime stability directly and threatens the flood control safety on both sides of the river seriously. In this paper, based on the measured cross-sectional data of Baihezhen-Gaocun reach of the LYR from 2001 to 2021, the evolution characteristics of the morphological parameters of cross-section were analyzed. On this basis, Heigangkou-Liuyuankou reach was selected as the proto type and a physical model experiment was conducted, to quantitatively reveal the adjustment of cross-sectional morphology under non-equilibrium sediment transport conditions. The analysis of the prototype measurement data found that cross-sectional morphology of the Huayuankou-Jiahetan reach was more variable compared with other sections of the LYR. A typical river section in the Huayuankou-Jiahetan reach was selected as the prototype, and a physical model was constructed using a horizontal scale of 600 and a vertical scale of 60. Keeping the same initial river boundary conditions, channel morphology adjustment experiments with four types discharges of 2 000 m³/s, 3000 m³/s, 4000 m³/s and 5 000 m³/s and different inlet sediment concentration were carried out. The experiment results show that when the inlet sediment concentration is small, the main channel erosion, the area increases and the river phase coefficient decreases. When the inlet sediment concentration is large, the main channel sedimentation, the area decreases and the river phase coefficient increases. Comparing the experimental data with the prototype data, the analysis reveals that the morphological parameters at river reach scale are well correlated with the incoming sediment coefficient under non-equilibrium sediment transport conditions, among which the main channel area is exponentially negatively correlated with the incoming sand coefficient, and the river phase coefficient is qua- dratically correlated with the incoming sediment coefficient. [ABSTRACT FROM AUTHOR]

In order to solve the problems of low measurement efficiency and high safety risks of personnel working on the line faced by the traditional single-point measurement means in the cross-section measurement of existing lines, vehicle-mounted mobile measurement technology was adopted to carry out the application research of cross-section measurement of existing railroads, and the process and method of technology application were introduced from three aspects: acquisition equipment, data acquisition and data solving. Based on the LiDAR point cloud of the whole section along the railroad line rapidly collected by the technology, the rail model reconstruction and route center extraction method with POS trajectory line guidance and two-step ICP alignment was proposed, and on this basis, the data processing method of section point cloud segmentation and attribute point automatic calculation was designed, which realized the rapid batch production of the results of the cross-sectional measurement of the existing railway lines. Combined with the application of a railroad project to build a second line, the results show that: the elevation accuracy is 19. 2 mm, distance accuracy is 16. 1 mm, which meet the specification requirements of the reconstruction of railroad engineering measurement. The method can effectively improve the efficiency of the existing line cross-section measurement, significantly reduce the amount of on-line work, and change the status that railroad crosssection measurement mainly depends on the manpower, which provides technical support and safety guarantee for the existing railroad cross-section fast measurement. [ABSTRACT FROM AUTHOR]

The NIRR-1 went through conversion from highly enrich uranium HEU to low enriched Uranium LEU fuel. The design of the fuel core is such that the cladding materials have been changed from aluminum to zirconium. The cladding materials may likely experience neutron dose which is susceptible to degradation of the materials. Hence, the needs to ascertain the level of degradation of the materials are crucial. Therefore, we calculate the reaction cross section of Al and Zr target with EMPIRE 3.2.3 modular nuclear reaction code. The calculated results were compared with measured data from EXFOR and the Evaluated Nuclear Data (ENDF). Comparative assessment of neutronic impact of Al and Zr used in the high and low enrich uranium fuel in NIRR-1 were carry out by compared cross section of Al with Zr results in the reaction channel relevance to the cladding materials. The results show that 90Zr(n, el) have high mean cross section of 1720.30 mb and 90Zr(n, y) with lower mean cross section of 0.54 mb while 27Al(n, p) and 27Al(n, y) high and low mean cross section is 482.5 mb and 0.022 mb respectively. It was observed that Zr target absorption cross section is better compared to Al target. This indicates that Zr has proven higher resistance to corrosion and longevity in terms of degradation as cladding materials. [ABSTRACT FROM AUTHOR]

We propose a risk factor for idiosyncratic entropy and explore the relationship between this factor and expected stock returns. We estimate a cross-sectional model of expected entropy that uses several common risk factors to predict idiosyncratic entropy. We find a negative relationship between expected idiosyncratic entropy and returns. Specifically, the Carhart alpha of a low expected entropy portfolio exceeds the alpha of a high expected entropy portfolio by −2.37% per month. We also find a negative and significant price of expected idiosyncratic entropy risk using the Fama-MacBeth cross-sectional regressions. Interestingly, expected entropy helps us explain the idiosyncratic volatility puzzle that stocks with high idiosyncratic volatility earn low expected returns. We propose a risk factor of idiosyncratic entropy and explore the relationship between this factor and expected stock returns. Interestingly, expected entropy helps us explain the idiosyncratic volatility puzzle that stocks with high idiosyncratic volatility earn low expected returns.

Debris flows and floods generated by rainfall runoff occur in rocky mountainous landscapes and burned steeplands. Flow type is commonly identified post‐event through interpretation of depositional structures, but these may be poorly preserved or misinterpreted. Prior research indicates that discharge magnitude is commonly amplified in debris flows relative to floods due to volumetric bulking and increased frictional resistance. Here, we use this flow amplification to develop a metric (Q*) to separate debris flows from floods based on the ratio of observed peak discharge to the theoretical maximum water discharge from rainfall runoff. We compile 642 observations of floods and debris flows and demonstrate that Q* distinguishes flow type to ∼92% accuracy. Q* allows for accurate identification of debris flows through simple channel cross‐section surveys rather than through qualitative interpretation of deposits, and therefore should increase the performance of models and engineered structures that require accurate flow‐type observations. Plain Language Summary: Steep channels in rocky landscapes and recently burned areas carry a wide range of flow types, ranging from water floods to highly destructive debris flows composed of rock, sediment, other incidental debris, and water. Typically, the flow type that recently occurred in a channel is identified by interpreting the structure of deposits left behind by the flow. However, these deposits can be challenging to interpret, provided they are preserved at all. Prior research has shown that the shift in flow physics occurring in debris flows has the effect of amplifying the magnitude of the flow beyond that which is possible in floods. In this study, we take advantage of this flow amplification to develop a quantitative metric that allows for flow type to be identified without interpreting depositional structures. We demonstrate the metric to be highly accurate. This methodology should increase the accuracy of predictive models trained on such observations, which can help to better understand where these hazards exist and protect communities and infrastructure at risk. Key Points: To distinguish debris flows from floods, a metric Q* equal to the ratio of peak discharge to rainfall‐runoff discharge is developedQ* separates floods (Q* ≤ 1) from debris flows (Q* > 1) to ∼92% accuracy and is robust to uncertainties in the key parametersThe Q* metric should reduce misidentification of flow type and increase the performance of empirical‐hazard models and hazard mitigation [ABSTRACT FROM AUTHOR]

Gamma emission induced by the irradiation of nickel and zirconium with fission neutrons was investigated with the FaNGaS (Fast Neutron–induced Gamma-ray Spectrometry) instrument operated at Heinz Maier-Leibnitz Zentrum. Measurements were done at an angle of 90° with respect to the direction of the fission neutron beam (average neutron energy of 2.18 MeV). We report on the relative intensities and production cross sections of 265 gamma lines (163 for nickel and 102 for zirconium). Consistency with available literature data was evaluated. The cross section of the 90Zr(n,n′)90mZr reaction was determined to be 88 ± 8 mb. For a counting time of 12 h, the detection limits of 0.7 and 1.3 mg were estimated for nickel and zirconium, respectively. [ABSTRACT FROM AUTHOR]

The e + N2 scattering system is usually a typical testing model in electron scattering from molecule. The accurate resonant and the non-resonant differential cross sections (DCSs), integral cross sections (ICSs) and momentum transfer cross sections (MTCSs) of electron scattering from N2 molecule are studied using limited experimental DCSs and the difference converging method for electron scattering (DCMe) proposed in our previous work. The DCMe results well represent those known experimental data and obtain all unknown ones at given energies. It supplies a theoretical alternative to correctly predict the DCSs those may be experimentally unknown or hard to have quantum mechanically. This study shows that. [ABSTRACT FROM AUTHOR]

In this work, the excitation functions of 10B(d,n)11C, 11B(d,n)12C, 11B(d,2n)11C, 11B(d,p)12B, 12C(d,n)13N, 12C(d,t)11C and 12C(d, α )10B reactions were considered by theoretical models available in EMPIRE 3.2.3, TALYS 1.95 and ALICE/ASH codes from threshold up to 30 MeV energy. Nuclear model calculations were performed using different input parameters for the equilibrium and pre-equilibrium reaction processes. Various nuclear models were used to analyze the contribution of the PCROSS mean free path value, initial exciton number and level density models on excitation functions. The present data were compared with the available literature experimental data to examine the validity of the nuclear models. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to present the classification of navicular bones and the anatomical basis for the diagnosis and treatment of navicular fractures of the foot. Method: 351 computed tomographic (CT) images of the navicular bone were analyzed and classified. The navicular bone's anatomical morphology was measured by three independent researchers in each type. Analysis and recording of the measurement results followed. Result: Navicular bones were assorted into three types: I shape(37.04%), II shape(54.41%), and III shape(8.55%). The left and right sides did not differ in any appreciable ways, except ab, bc, and ∠abc (P < 0.05); And all data were statistically different between men and women except for ∠abc (p > 0.05). Conclusion: The classification of the navicular bone in this study may be helpful in making the treatment decision for navicular fracture. Level of clinical evidence: : 4. [ABSTRACT FROM AUTHOR]

The single-center convergent close-coupling (CCC) method is applied to calculate positron scattering from boron. A model potential approach is utilized to extract the positronium formation, direct ionization, and values between the positronium formation and ionization thresholds. We present results for total, electron loss, elastic, momentum transfer, total bound state excitation, positronium formation, direct ionization, stopping power, and mean excitation energy from 10 − 5 eV to 5000 eV. For boron, there is only one other set of theoretical positron calculations for elastic and momentum transfer above 500 eV, which is in excellent agreement with the current CCC results. Using the current results for boron atoms and previous CCC calculations for hydrogen and fluorine atoms, positron scattering from BF, BF 2 , BF 3 , and BH molecules is calculated for energies between 0.1 eV and 5000 eV with a modified independent atom approach. [ABSTRACT FROM AUTHOR]

We propose a semi-empirical formula for the cross section of ionization by electron impact. The formula involves adjustable parameters which are determined by comparison with measured or numerically calculated cross sections. In the latter case, the ions are perturbed by their environment which is a high-density plasma. As a consequence, the cross section is significantly modified. We investigate Be-like carbon, nitrogen and oxygen as well as aluminum ions. We also show that the formula is well-suited for interpolation and extrapolation. Knowing the cross section, we calculate the rate coefficient within the Boltzmann and Fermi–Dirac statistics. In the first case, the rate can be calculated analytically. In the second one, it can be expressed in terms of special functions, but the numerical evaluation is more convenient while providing accurate results. Our results are compared to experiment and to other calculations. [ABSTRACT FROM AUTHOR]

An accurate and computationally efficient determination of the cross sections for electron collision ionization of molecules has various applications, such as plasma physics and atmospheric science. In the case of large molecules, ab initio calculations are often difficult and time‐consuming. Here, we develop a feed forward neural network to predict the electron impact ionization cross sections of complex molecules. The training (predicting) set in the method consists of a series of theoretical ionization cross sections for small (large) molecules obtained from the combined model, which integrates the Binary‐Encounter‐Bethe and Deutsch‐Märk models. Several complex systems or targets involving electron collision ionization are evaluated, including molecules such as CH4$$ {}_4 $$, C3$$ {}_3 $$H8$$ {}_8 $$, C5$$ {}_5 $$H8$$ {}_8 $$, C6$$ {}_6 $$H10$$ {}_{10} $$, C6$$ {}_6 $$, C2$$ {}_2 $$H6$$ {}_6 $$O, and C6$$ {}_6 $$H6$$ {}_6 $$O. The root mean square errors of the trained and predicted cross sections by the 2×3×3×1$$ 2\times 3\times 3\times 1 $$ neural network (compared to the values from the combined model) are found to be approximately.0086 and.0930 (in 10−20$$ {}^{-20} $$ cm2$$ {}^2 $$), respectively, (using the C2$$ {}_2 $$H6$$ {}_6 $$O molecule as an example), indicating our results are very high accuracy. The excellent agreement between the predicted values and the actual values indicates that the neural network is a practical and powerful tool for determining the electron collision ionization cross sections of complex molecules and can provide valuable insights into the dynamics process. Apart from its fundamental importance, this study has far‐reaching implications for gas discharge, low‐temperature plasmas, and fusion edge plasmas and so forth. [ABSTRACT FROM AUTHOR]

A macroscopic cross section generation model was developed for the conceptual horizontal, compact high temperature gas reactor (HC-HTGR). Because there are many sources of spectral effects in the design and analysis of the core, conventional LWR methods have limitations for accurate simulation of the HC-HTGR using a neutron diffusion core neutronics simulator. Several super-cell model configurations were investigated to consider the spectral effect of neighboring cells. A new history variable was introduced for the existing library format to more accurately account for the history effect from neighboring nodes and reactivity control drums. The macroscopic cross section library was validated through comparison with cross sections generated using full core Monte Carlo models and single cell cross section for both 3D core steady-state problems and 2D and 3D depletion problems. Core calculations were then performed with the AGREE HTR neutronics and thermal-fluid core simulator using super-cell cross sections. With the new history variable, the super-cell cross sections were in good agreement with the full core cross sections even for problems with significant spectrum change during fuel shuffling and depletion.

Aerial surveying with unmanned aerial vehicles (UAVs) has been popularly employed in river management and flood monitoring. One of the major processes in UAV aerial surveying for river applications is to demarcate the cross-section of a river. From the photo images of aerial surveying, a point cloud dataset can be abstracted with the structure from the motion technique. To accurately demarcate the cross-section from the cloud points, an appropriate delineation technique is required to reproduce the characteristics of natural and manmade channels, including abrupt changes, bumps and lined shapes. Therefore, a nonparametric estimation technique, called the K-nearest neighbor local linear regression (KLR) model, was tested in the current study to demarcate the cross-section of a river with a point cloud dataset from aerial surveying. The proposed technique was tested with synthetically simulated trapezoidal, U-shape and V-shape channels. In addition, the proposed KLR model was compared with the traditional polynomial regression model and another nonparametric technique, locally weighted scatterplot smoothing (LOWESS). The experimental study was performed with the river experiment center in Andong, South Korea. Furthermore, the KLR model was applied to two real case studies in the Migok-cheon stream on Hapcheon-gun and Pori-cheon stream on Yecheon-gun and compared to the other models. With the extensive applications to the feasible river channels, the results indicated that the proposed KLR model can be a suitable alternative for demarcating the cross-section of a river with point cloud data from UAV aerial surveying by reproducing the critical characteristics of natural and manmade channels, including abrupt changes and small bumps as well as different shapes. Finally, the limitation of the UAV-driven demarcation approach was also discussed due to the penetrability of RGB sensors to water. [ABSTRACT FROM AUTHOR]

The application of ICESAT-2 altimetry data in river hydrology critically depends on the accuracy of the mean water surface elevation (WSE) at a virtual station (VS) where satellite observations intersect solely with water. It is acknowledged that the ATL13 product has noise elevations of the adjacent land, resulting in biased high mean WSEs at VSs. Earlier studies have relied on human intervention or water masks to resolve this. Both approaches are unsatisfactory solutions for large river basins where the issue becomes pronounced due to many tributaries and meanders. There is no automated procedure to partition the truly representative water height from the totality of the along-track ICESAT-2 photon segments (portions of photon points along a beam) for increasing precision of the mean WSE at VSs. We have developed an automated approach called "auto-segmentation". The accuracy of our method was assessed by comparing the ATL13-derived WSEs with direct water level observations at 10 different gauging stations on 37 different dates along the Lower Murray River, Australia. The concordance between the two datasets is significantly high and without detectable bias. In addition, we evaluated the effects of four methods for calculating the mean WSEs at VSs after auto-segmentation processing. Our results reveal that all methods perform almost equally well, with the same R2 value (0.998) and only subtle variations in RMSE (0.181–0.189 m) and MAE (0.130–0.142 m). We also found that the R2, RMSE and MAE are better under the high flow condition (0.999, 0.124 and 0.111 m) than those under the normal-low flow condition (0.997, 0.208 and 0.160 m). Overall, our auto-segmentation method is an effective and efficient approach for deriving accurate mean WSEs at river VSs. It will contribute to the improvement of ICESAT-2 ATL13 altimetry data utility on rivers. [ABSTRACT FROM AUTHOR]

Fission fragments mass distribution and fission cross section for proton-induced fission of some isotopes of Thorium and Uranium at low energies are simulated. A phenomenological method is employed to estimate the fragments mass distribution of 230 , 232 , 234 Th and 233 , 235 , 238 U isotopes. The Prokofiev semi-empirical method was also employed in order to obtain the fission cross sections of proton-induced fission of 232 Th and 233 , 234 , 235 , 236 , 238 U isotopes. The adjustable parameters of these phenomenological approaches are obtained using available experimental data in a given energy by the least squares method. Consequently, the calculated fragments mass distribution and fission cross sections are compared with the available experimental data. The obtained results reveal that the fragments mass distribution and the proton-induced fission cross sections are in a good agreement with the available experimental data. [ABSTRACT FROM AUTHOR]

It has been three decades since pulsating heat pipes were first introduced and garnered more attention due to their uncomplicated structural design and superior heat transfer capabilities. The pulsating heat pipe of the original design is strongly affected by space orientation, which is connected with the influence of gravity. Even though more turns will hold pulsating heat pipe operational in any orientation, more space is needed to handle pulsating heat pipes, limiting its potential in space and the power electronics industry. This paper aims to present a comprehensive review of pulsating heat pipe's progress based on the most recent findings of both experimental and theoretical investigations of parametric influence on pulsating heat pipe thermal performance in horizontal and top heating modes. It aims to identify research gaps in pulsating heat pipe functioning in different orientations. Additionally, a comparative analysis of pulsating heat pipe design features described in the existing literature is conducted to determine the most promising designs for orientation-independent pulsating heat pipe systems. It is concluded that the integration of design attributes, encompassing an uneven-turn design, a channel structure featuring alternating shapes and size of cross-section, and the utilization of nanofluids and binary mixtures as heat carriers are expected to serve as the basic reference for researchers aiming to achieve a stable pulsating heat pipe operation devoid of gravitational influences. [ABSTRACT FROM AUTHOR]

Due to the availability of fuel, favorable kinetics, and high output energy, the deuterium-tritium (D-T) fusion reaction is dominantly used in thermonuclear fusion. This paper presents a detailed, step-by-step theoretical calculation of the D-T fusion cross-section within the framework of the phenomenological R-matrix method. The fundamental principles of the phenomenological R-matrix method are outlined. Nuclear and Coulomb interactions are addressed by the R-matrix formalism, which classifies the configuration space into internal and external regions, respectively. Precise Coulomb functions are utilized in the calculations, essential for the accurate determination of the penetration and shift factors. Precise Coulomb functions for the D+T, 4He+12C systems have been calculated. The penetration and shift factors for the D+T system for a given angular momentum have been obtained. Two different R-matrix models with parameters from recent scientific papers are employed to calculate D-T fusion cross-sections and reaction rates, which are then compared with those obtained from the ENDF/B-VIII.0 library data. Within a crucial low-energy range (from 0 to 0.1 MeV), important for fusion technology, our results show quite good agreement with experimental data, while in a high-energy range, the obtained results are slightly underestimated due to non-resonant 5He levels not being taken into account. These findings indicate that the models can be used for future thermonuclear fusion applications. [ABSTRACT FROM AUTHOR]

The article considers two variants of the algorithm for optimizing excavation units. In recent decades, coal mining and mining of other minerals in underground conditions have begun to face growing challenges, such as increased labor costs, regulatory changes and the constant need to optimize processes. In this context, the introduction of modern technologies such as MICROMINE software provides unique opportunities for optimizing underground mining units. The dredging Unit optimizer determines the optimal combination of parent blocks that need to be mined in order to maximize the overall profit from the development of the field. At the same time, some technological limitations are taken into account. If, in the case of optimization of open-pit mining, technological limitations mean the angles of the slopes of the sides of quarries, then the minimum dimensions and shape of the excavation units are taken into account when optimizing the excavation units. An economic approach combining cost reduction, increased production and risk minimization makes MICROMINE an important tool in the mining industry. In this paper, the aim is to identify an algorithm for optimizing underground excavation units using MICROMINE software and highlight the advantages of using this software. [ABSTRACT FROM AUTHOR]

The thermal-hydraulic performance of plain tubes with and without wire coils in turbulent regimes is investigated experimentally and numerically. The effects of wire coil distribution (circular cross section) within the tube were explored experimentally, and water was employed as the working fluid. The numerical simulation was carried out using software programmer ANSYS Fluent 2019 R3 using the finite-volume approach. In the turbulent regime, six cross-sectioned wire coils were analyzed, including: circular, rectangular, hexagonal, square, star shape, and triangle. The utilization of a tube with a wire coil has been shown to increase heat transfer rate and pump consumption. The results indicate a high level of concurrence, as the deviations are all below 8%. Compared with plain tube, the wire coils, according to the arrangement (TWD), gave the best PEC. The heat transfer enhancement ability of different cross sections follows the following order: StCS > RCS > HCS > SqCS > CCS > TCS. Also, the sequence of pump consumption for each cross section is as follows: RCS > StCS > SqCS > HCS > CCS > TCS. [ABSTRACT FROM AUTHOR]

Copyright of Transportation Science & Technolgy is the property of Transportation Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polymers and polymer composites are frequently used in tribological applications. However, their use is often limited by excessive wear or plastic deformation, therefore research and development aiming to improve the materials is ongoing. Tribological evaluations of polymer composites often study the friction coefficient and wear rate for different types, sizes and amounts of fillers. But rarely are any mechanisms presented. Although polymer materials differ from metals, the techniques typically used for metal components, for example, scanning electron microscopy (SEM) and energy dispersive x‐ray spectroscopy (EDS), can be adapted to polymer materials, to achieve more informative SEM micrographs and EDS analyses. The aim of this article is to present useful analysis strategies, from sample preparation and selection of viewing angles, to selection of instrument settings and detector types. The strategies are exemplified by analysis of poly‐phenylene‐sulphide filled with glass fiber, evaluated against steel in a reciprocating ball‐on‐flat test set‐up. This article takes its starting point with the worn surfaces, and subsequently analyze them using SEM and EDS. A selection of cross section preparation techniques, analysis parameters and microscopy settings are presented and discussed. By combining these techniques and settings, the observation of a strongly modified surface layer, as well as sub‐surface plastic deformation and imbedded wear particles, is facilitated. [ABSTRACT FROM AUTHOR]

Prompt gamma rays of terbium emitted after (n,nʹγ) inelastic scattering reactions induced by irradiation of a terbium(III) hexahydrate (TbCl3·6H2O) sample with a beam of fission neutrons were investigated with the instrument FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) at an angle of 90° between neutron beam and detector. At sample position, the fast-neutron flux was 1.13 × 108 cm−2 s−1 and the neutron beam has an average energy of 2.30 MeV. We identified 124 prompt gamma lines from the 159Tb(n,nʹγ)159Tb reaction. Presence of prompt gamma rays from oxygen and chlorine was used for a concise verification of recently published results. Relative gamma-ray intensities, effective cross sections and fast-neutron spectrum-averaged partial production cross sections of the gamma lines are given including comparisons with available literature data. We found a reasonable agreement and the multitude of unreported lines adds decisive value to nuclear spectroscopy. Additionally, we estimated the detection limit of terbium as 1 mg for a counting time of 12 h. [ABSTRACT FROM AUTHOR]

Excitation functions for the formation of the radionuclides 51Cr, 52Mn and 54Mn via deuteron-induced activation of natural iron were measured up to deuteron energies of 35 MeV. The available experimental databases of the reaction products 51Cr, 52Mn and 54Mn were extended and compared with the nuclear model calculations using the TALYS code. The model calculations reproduce our measured data after a careful choice of the input model parameters. Some information obtained on competition between the emission of multinucleons and a bound α-particle. [ABSTRACT FROM AUTHOR]

Liquid argon technology is widely used by many previous and current neutrino experiments, and it is also promising for future large-scale neutrino experiments. When detecting neutrinos using liquid argon, many hadrons are involved, which can also interact with argon nuclei. In order to gain a better understanding of the detection processes, and to simulate neutrino events, knowledge of hadron-argon cross sections is needed. This paper describes a new procedure which improves upon the previous work with multi-dimensional unfolding to measure hadron-argon cross sections in a liquid argon time projection chamber. Through a simplified version of simulation, we demonstrate the validity of this procedure. [ABSTRACT FROM AUTHOR]

Abstract Debris flows and floods generated by rainfall runoff occur in rocky mountainous landscapes and burned steeplands. Flow type is commonly identified post‐event through interpretation of depositional structures, but these may be poorly preserved or misinterpreted. Prior research indicates that discharge magnitude is commonly amplified in debris flows relative to floods due to volumetric bulking and increased frictional resistance. Here, we use this flow amplification to develop a metric (Q*) to separate debris flows from floods based on the ratio of observed peak discharge to the theoretical maximum water discharge from rainfall runoff. We compile 642 observations of floods and debris flows and demonstrate that Q* distinguishes flow type to ∼92% accuracy. Q* allows for accurate identification of debris flows through simple channel cross‐section surveys rather than through qualitative interpretation of deposits, and therefore should increase the performance of models and engineered structures that require accurate flow‐type observations.

The differential cross section for Z0 production, measured as a function of the boson's transverse momentum (pT), provides important constraints on the evolution of the transverse momentum dependent parton distribution functions (TMDs). The transverse single spin asymmetry (TSSA) of the Z0 is sensitive to one of the polarized TMDs, the Sivers function, which is predicted to have the opposite sign in p+p →W/Z+X from that which enters in semi-inclusive deep inelastic scattering. In this Letter, the STAR Collaboration reports the first measurement of the Z0/γ⁎ differential cross section as a function of its pT in p+p collisions at a center-of-mass energy of 510 GeV, together with the Z0/γ⁎ total cross section. We also report the measurement of Z0/γ⁎ TSSA in transversely polarized p+p collisions at 510 GeV.

The article explores the methods and potential applications of terrestrial laser scanning technology. It also presents the preliminary results of scanning the Bijambare cave, where a georeferenced three-dimensional model of the cave's interior was created. This model, based on available data, stands as the first accurate 3D representation of a speleological object in Bosnia and Herzegovina. The first section of the paper provides a brief overview of the Bijambare cave area and the laser scanning technology employed, highlighting its advantages over other geodetic measurement techniques. Subsequently, the text delves into the stages of the measurement processing, followed by an examination of the various products generated. The practical significance of these products is illustrated using the example of the Bijambare cave.

We theoretically study the state‐selected photo‐recombination process of highly charged ions using the close‐coupling approximation and the full relativistic Dirac R‐matrix method combined with the Dirac Atomic R‐matrix Codes (DARC). Focusing on the interference between the direct and indirect processes and the relativistic effects on the spin‐orbit splitting, we calculate the total and partial photo‐recombination cross sections of the H‐like Ne9+, Cl16+, Fe25+, and Kr35+ ions. The energies of the incident electrons are considered as in the KLL resonant regions, in which the initial state is the 1s ground state of the H‐like ions and the recombined states includes the ground state (1s2)1S0 and six lower excited states (1s2s)1S0,3S1, and (1s2p)3P0,1,2,1P1 of the He‐like ions. We utilize the multi‐configuration Dirac‐Fock method to calculate the target state wavefunctions, transition energies, and transition probabilities of both the one‐electron one‐photon (OEOP) and two‐electron one‐photon (TEOP) transitions from the resonant captured states to the recombined states. By analyzing the calculated atomic data, we identify all resonant peaks in each partial photo‐recombination process, and our results agree well with the available results in literature. Our study reveals a significant interference effect in the photo‐recombination cross sections, especially in the partial cross sections. Moreover, we present the eigenphase as a function of the electron energy for each partial photo‐recombination channel. [ABSTRACT FROM AUTHOR]

The article explores the methods and potential applications of terrestrial laser scanning technology. It also presents the preliminary results of scanning the Bijambare cave, where a georeferenced three-dimensional model of the cave's interior was created. This model, based on available data, stands as the first accurate 3D representation of a speleological object in Bosnia and Herzegovina. The first section of the paper provides a brief overview of the Bijambare cave area and the laser scanning technology employed, highlighting its advantages over other geodetic measurement techniques. Subsequently, the text delves into the stages of the measurement processing, followed by an examination of the various products generated. The practical significance of these products is illustrated using the example of the Bijambare cave. [ABSTRACT FROM AUTHOR]

Electron impact scattering from C 3 F 6 O is studied in this work. The R-matrix method was used for the calculations of elastic, momentum transfer, and excitation cross sections. The attachment cross section was obtained through a parametric estimator based on the R-matrix outputs. The Binary-Encounter-Bethe (BEB) method was used for computing the ionization cross section. The obtained cross section set was used for the transport studies using the BOLSIG+ code, which is a two-term Boltzmann equation solver. The present calculation was performed for steady-state Townsend experimental conditions for E/N, covering a range of 100–1000 Td. The critical dielectric strength of pure C 3 F 6 O was found to be 475 Td, which is much greater than that of SF 6 (355 Td). The effect of the addition of different buffer gases, such as CO 2 , N 2 , and O 2 , was also examined. For the C 3 F 6 O–CO 2 , C 3 F 6 O–N 2 , and C 3 F 6 O–O 2 mixtures with 65%, 55%, and 60% C 3 F 6 O, respectively, the critical dielectric strength was determined to be essentially the same as that of pure SF 6 . The presence of synergism was confirmed for these gas mixtures. We further derived the Paschen curve using a fitting method with the transport parameters as the basic inputs. The minimum breakdown voltage of C 3 F 6 O accounted for only 55% of that of SF 6 . The buffer gas mixture improved the condition; however, the performance of CO 2 and O 2 mixtures was not satisfactory. The addition of N 2 as the buffer gas significantly improved the breakdown property of the gas. The mixture of ≥99% of N 2 or ≤1% of C 3 F 6 O gave a better breakdown characteristic than SF 6 . Any proportion ≥90% of N 2 or ≤10% of C 3 F 6 O was suitable in the higher pressure ranges. The present work demonstrates the potential of C 3 F 6 O as a substitute gas for SF 6 with a negligible environmental threat. [ABSTRACT FROM AUTHOR]

This work analyzes hemodynamic phenomena within the aorta of two elderly patients and their impact on blood flow behavior, particularly affected by an endovascular prosthesis in one of them (Patient II). Computational Fluid Dynamics (CFD) was utilized for this study, involving measurements of velocity, pressure, and wall shear stress (WSS) at various time points during the third cardiac cycle, at specific positions within two cross sections of the thoracic aorta. The first cross-section (Cross-Section 1, CS1) is located before the initial fluid bifurcation, just before the right subclavian artery. The second cross-section (Cross-Section 2, CS2) is situated immediately after the left subclavian artery. The results reveal that, under regular aortic geometries, velocity and pressure magnitudes follow the principles of fluid dynamics, displaying variations. However, in Patient II, an endoprosthesis near the CS2 and the proximal border of the endoprosthesis significantly disrupts fluid behavior owing to the pulsatile flow. The cross-sectional areas of Patient I are smaller than those of Patient II, leading to higher flow magnitudes. Although in CS1 of Patient I, there is considerable variability in velocity magnitudes, they exhibit a more uniform and predictable transition. In contrast, CS2 of Patient II, where magnitude variation is also high, displays irregular fluid behavior due to the endoprosthesis presence. This cross-section coincides with the border of the fluid bifurcation. Additionally, the irregular geometry caused by endovascular aneurysm repair contributes to flow disruption as the endoprosthesis adjusts to the endothelium, reshaping itself to conform with the vessel wall. In this context, significant alterations in velocity values, pressure differentials fluctuating by up to 10%, and low wall shear stress indicate the pronounced influence of the endovascular prosthesis on blood flow behavior. These flow disturbances, when compounded by the heart rate, can potentially lead to changes in vascular anatomy and displacement, resulting in a disruption of the prosthesis-endothelium continuity and thereby causing clinical complications in the patient.

In this article, we report a new empirical formula for quick calculation of cross sections of (n, α) reactions with 14–15 MeV neutrons. Cross sections are analysed in terms of the compound nucleus model. A systematic trend for 14–15 MeV neutrons is found in the variation of (n, α) reaction cross sections with the parameters (N − Z + 1), (En+Q)0.5 and N/Z. The empirical relation between the cross sections and these parameters has been obtained, which give fairly good fits with the experimental data. We have also investigated the odd-even effects on (n, α) cross sections considering binding energy systematic of the shell model. The present formula is very useful in predicting of the (n, α) cross sections, where the measurements are not available as well as in testing new experimental data.

The single-center convergent close-coupling (CCC) method is applied to calculate positron scattering from boron. A model potential approach is utilized to extract the positronium formation, direct ionization, and values between the positronium formation and ionization thresholds. We present results for total, electron loss, elastic, momentum transfer, total bound state excitation, positronium formation, direct ionization, stopping power, and mean excitation energy from 10−5 eV to 5000 eV. For boron, there is only one other set of theoretical positron calculations for elastic and momentum transfer above 500 eV, which is in excellent agreement with the current CCC results. Using the current results for boron atoms and previous CCC calculations for hydrogen and fluorine atoms, positron scattering from BF, BF2, BF3, and BH molecules is calculated for energies between 0.1 eV and 5000 eV with a modified independent atom approach.