bluuebunny/crossref_metadata_2025 huggingface dataset:
Appendix gap losses in Stirling engines – review of recent findings
Authors: Kühl Hans-Detlev , Sauer Jan
Published: October 2021

The appendix gap loss in Stirling cycle machines is generated by the annular gap around the thermally insulating, thin-walled dome typically attached to a piston or displacer plunging into the hot cylinder volume of an engine or the cold volume of a cryocooler. It was considered to be of minor importance for decades. Thus, simplified analytical models were considered sufficiently accurate for its description, until numerical simulations and experimental results gave rise to a more detailed analysis revealing that, neglecting entrance and end effects, the flow is typically laminar, but unsteady. Subsequently, an enhanced analytical model accounting for fluidic and thermal inertia effects as well as the volumetric displacement by the seal was developed. Compared to the previous ones, this model predicts a shift of the optimum width to smaller values, a higher minimum overall loss and furthermore, an option to decrease the loss by reducing the effective seal diameter. This could be experimentally confirmed as well as the unsteady gas temperature profiles predicted by this model. Subsequently, both theoretically and experimentally founded correlations for the radial and axial energy transport in the gap were derived and implemented in a differential simulation of the gap within a third order code.
Introduction to thermoacoustic Stirling engines: First steps and praxis
Authors: Iniesta Carmen , Olazagoitia José Luis , Gros Jaime , Vinolas Jordi , Aranceta Javier
Published: October 2021

The work focuses on the theoretical study and design of Thermoacoustic Stirling-Like Cycle Engines. One of the main goals of this study is to describe the application of a methodology for energy analysis and optimization of thermoacoustic devices. This new approach avoids complicated mathematical treatments, facilitates access to this fascinating technology for all audiences. The presented methodology is based on the distribution of the active and reactive acoustic power flow according to the passive acoustic circuit. In addition, this methodology allows optimizing the device by comparing different acoustic circuits. This method is evaluated at a theoretical level with the models and simulations developed, for each of the case studies described. Besides, this publication shows the praxis from the first steps, so the reader is guided in the design and manufacture of a compact Stirling thermoacoustic energy recovery engine, operating in laboratory conditions. The resulting demonstrator is itself an academic tool for knowledge transfer.
Leaf inclination angle and foliage clumping in an evergreen broadleaf
Authors: Pisek Jan , Řezníčková Ladislava , Adamson Kairi , Ellsworth David S.
Published: October 2021

How leaves are presented affects interaction of atmospheric CO2, energy (light), and plant physiology. Plant productivity is primarily determined by the amount of leaf area, leaf orientation and distribution in space. Not much attention has been paid to possible changes in leaf orientation and distribution with elevated CO2, but its effect on plant growth could alter the proportions of sunlit and shaded leaf areas and feedback on carbohydrate available for further growth. We report on first measurements of leaf inclination angle distribution and foliage clumping in a native evergreen Eucalyptus woodland in ambient CO2 and under +150 ppm elevated CO2. We found that a spherical leaf angle distribution was not an appropriate supposition for present species (Eucalyptus tereticornis Sm.) at this site. Our measurements of leaf inclination angles from imagery indicated an erectophile, highly skewed unimodal leaf inclination angle distribution function. We conclude that despite the measured steeper angles under elevated CO2 concentrations, the leaf angle change is not significant and falls within the expected natural variability and uncertainties connected with the measurement method. The lack of a clear response of leaf orientation and foliage clumping to elevated CO2 concentration indicates that the previously produced datasets of leaf inclination angles and foliage clumping maps with Earth observation data may be suitable while modelling carbon and water cycles under climate change.
Cochlear outer hair cell electromotility enhances organ of Corti motion on a cycle-by-cycle basis at high frequencies in vivo
Authors: Dewey James B. , Altoè Alessandro , Shera Christopher A. , Applegate Brian E. , Oghalai John S.
Published: October 2021

Significance

The remarkable high-frequency sensitivity of mammalian hearing depends on the amplification of sound-evoked cochlear vibrations by outer hair cells. One way that outer hair cells are proposed to generate amplifying forces is through voltage-driven changes in cell length. However, it remains unclear whether this electromotility can work fast enough in vivo to provide amplification at the necessary frequencies. Here, we show that sound elicits motions within the living mouse cochlea that are fully consistent with electromotility. These motions are large relative to the motion of the underlying cochlear partition, including at high frequencies. The data therefore suggest that electromotility can indeed provide high-speed amplification in vivo.
Testing models at the neural level reveals how the brain computes subjective value
Authors: Williams Tony B. , Burke Christopher J. , Nebe Stephan , Preuschoff Kerstin , Fehr Ernst , Tobler Philippe N.
Published: October 2021

Significance

In recent years, models have played an increasingly important role for understanding the brain in cognitive, behavioral, and systems neuroscience. Decision neuroscience in particular has benefitted greatly from the application of economic models of choice preferences to neural data. However, an often-overlooked aspect is that many models of preferences have a generic problem—they make extremely similar behavioral predictions. Here, we demonstrate that to understand the mechanisms of valuation in the brain, it is useful to compare models of choice preferences not only at the behavioral but also at the neural level.
Dendrite tapering actuates a self-organizing signaling circuit for stochastic filopodia initiation in neurons
Authors: Mancinelli Gloria , Lamparter Lucas , Nosov Georgii , Saha Tanumoy , Pawluchin Anna , Kurre Rainer , Rasch Christiane , Ebrahimkutty Mirsana , Klingauf Jürgen , Galic Milos
Published: October 2021

Significance

Cellular signaling pathways respond to a wide range of stimuli. How signaling circuits are activated without an instructive stimulus and what this is good for are less clear. Combining theoretical and experimental approaches, we show that curvature-sensing proteins stabilize stochastic membrane deformations to nucleate a self-organizing actin-regulatory signaling circuit. In neurons, these signaling hubs control the initiation of exploratory filopodia that sample the cell vicinity for appropriate synaptic partners. The extent and diversity of proteins capable of forming self-organizing circuits at stochastically deformed membranes indicates a general signaling mechanism.
Sphingosine 1-phosphate receptor 5 (S1PR5) regulates the peripheral retention of tissue-resident lymphocytes
Authors: Evrard Maximilien , Wynne-Jones Erica , Peng Changwei , Kato Yu , Christo Susan N. , Fonseca Raissa , Park Simone L. , Burn Thomas N. , Osman Maleika , Devi Sapna , Chun Jerold , Mueller Scott N. , Kannourakis George , Berzins Stuart P. , Pellicci Daniel G. , Heath William R. , Jameson Stephen C. , Mackay Laura K.
Published: October 2021

Tissue-resident memory T (TRM) cells provide long-lasting immune protection. One of the key events controlling TRM cell development is the local retention of TRM cell precursors coupled to downregulation of molecules necessary for tissue exit. Sphingosine-1-phosphate receptor 5 (S1PR5) is a migratory receptor with an uncharted function in T cells. Here, we show that S1PR5 plays a critical role in T cell infiltration and emigration from peripheral organs, as well as being specifically downregulated in TRM cells. Consequentially, TRM cell development was selectively impaired upon ectopic expression of S1pr5, whereas loss of S1pr5 enhanced skin TRM cell formation by promoting peripheral T cell sequestration. Importantly, we found that T-bet and ZEB2 were required for S1pr5 induction and that local TGF-β signaling was necessary to promote coordinated Tbx21, Zeb2, and S1pr5 downregulation. Moreover, S1PR5-mediated control of tissue residency was conserved across innate and adaptive immune compartments. Together, these results identify the T-bet–ZEB2–S1PR5 axis as a previously unappreciated mechanism modulating the generation of tissue-resident lymphocytes.
NAP-XPS as a new tool for in-situ studies of SMOX gas sensors
Authors: Junker Benjamin , Favaro Marco , Starr David E , Hävecker Michael , Weimar Udo , Barsan Nicolae
Published: October 2021

The development of near ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) allows scientists to perform spectroscopic investigations of solid–gas interfaces at elevated pressures in a defined gas atmosphere. Due to the high surface sensitivity and element specificity, this technique promises to be a valuable and powerful tool in gas sensor research. A Pt doped SnO2 sample was studied to explore a variety of phenomena in sensor research that can be addressed using NAP-XPS at a synchrotron. The change of several parameters, including chemical shifts, band bending, and valence band structure, could be observed in-situ and highlights the enormous potential of the method in this field. Furthermore, a series of DC resistance measurements has been performed to study the impact of pressure. The decrease of resistance at low pressure strongly indicates that both the electronic characteristics as well as the surface composition under the conditions of NAP-XPS are dissimilar to operando conditions at atmospheric pressure.
Radiation exposure in the intra-arterial nimodipine therapy of subarachnoid hemorrhage related cerebral vasospasm
Authors: Opitz Marcel , Zensen Sebastian , Bos Denise , Wetter Axel , Kleinschnitz Christoph , Uslar Ellen , Jabbarli Ramazan , Sure Ulrich , Radbruch Alexander , Li Yan , Dörner Nils , Forsting Michael , Deuschl Cornelius , Guberina Nika
Published: October 2021

The selective intra-arterial nimodipine application for the treatment of cerebral vasospasm (CVS) in patients after spontaneous subarachnoid hemorrhage (sSAH) is widely employed. The purpose of this study is to examine the radiation exposure and to determine local diagnostic reference levels (DRLs) of intra-arterial nimodipine therapy. In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients undergoing (I) selective intra-arterial nimodipine application or (II) additional mechanical angioplasty for CVS treatment. Interventional procedures were differentiated according to the type of procedure and the number of probed vessels. Altogether 494 neurointerventional procedures of 121 patients with CVS due to sSAH could be included. The radiation exposure indices were distributed as follows: (I) DRL 74.3 Gy·cm2, AD 59.8 Gy·cm2; (II) DRL 128.3 Gy·cm2, AD 94.5 Gy·cm2. Kruskal–Wallis test confirmed significant dose difference considering the number of probed vessels (p< 0.001). The mean cumulative dose per patient was 254.9 Gy·cm2 (interquartile range 88.6–315.6 Gy·cm2). The DRLs of intra-arterial nimodipine therapy are substantially lower compared with DRLs proposed for other therapeutic interventions, such as thrombectomy or aneurysm coiling. However, repeated therapy sessions are often required, bearing the potential risk of a cumulatively higher radiation exposure.
Prediction of damage mechanisms of cross-ply composite materials using novel non-linear multiscale methodologies
Authors: Tsivolas Eleftherios , Gergidis Leonidas N , Paipetis Alkiviadis S
Published: October 2021

In the present work, a novel multiscale material methodology is applied to a finite element mesh of a cross-ply composite material in tension in order to study the progressive damage and failure of the material at multiple scales by combining damage evolution models and failure criteria in microscale and cohesive zone modeling in macroscale. The micromechanics user material (Umat) developed follows a nonlinear version of the Mori–Tanaka theory and is coupled with mesoscale damage model. The concept of this user material is to dehomogenize-localize the strain tensor at each integration point for each time increment using Eshelby’s theories and strain concentration tensors. This material implementation allows the researcher to analyze results at two scales in the post processing stage, both for the composite material and the constituents for each time increment. It is observed that in the multiscale model the results are closer to the experimental measurements and even more damage mechanisms can be predicted, such as matrix damage and fiber failure. The developed multiscale methodology is advantageous since the constituents can follow different material models, with many failure criteria. It is also capable of predicting stresses, strains, plastic strains and more analysis variables not only in the macroscale-homogeneous level but also in microscale constituent-wise level.
Macroscopic plasma analysis from 1D-radial kinetic results of a Hall thruster discharge
Authors: Marín-Cebrián Alberto , Domínguez-Vázquez Adrián , Fajardo Pablo , Ahedo Eduardo
Published: October 2021

A radial particle-in-cell model of the weakly-collisional plasma discharge in a Hall thruster, provides the non-Maxwellian velocity distribution functions (VDF) of ions and electrons. The model considers a radial magnetic field, secondary electron emission from the two walls, and phenomenological models of anomalous electron scattering. The electron VDF is used to assess the different terms in the macroscopic momentum and energy equations, identifying those differing from the standard fluid model for a near-Maxwellian VDF. The pressure tensor consists of an anisotropic gyrotropic part and a small gyroviscous part. Nonetheless, the gradient of this last one affects the cross-field electron current density, generating radial undulations that resemble those reported for near-wall conductivity. A gyroviscous energy flux is identified too. The heat flux parallel to the magnetic lines does not follow a conductive-type law but a convective-type one, already found in other weakly-collisional plasmas. The tails of the electron velocity distribution function are partially depleted due to wall collection, leading to reduced electron fluxes of particles and energy, which are characterized with parameters useful for fluid models. Differences in the plasma response for annular and planar channel geometries are highlighted. The levels of replenishment of the electron VDF and of the asymmetries in radial profiles differ for isotropic and anisotropic anomalous scattering models.
Resonant states and their role in nanophotonics
Authors: Both S , Weiss T
Published: October 2021

Resonant phenomena have been extensively used in micro- and nanophotonics. Mathematically, these phenomena originate in a discrete set of basis functions known as resonant states or quasi-normal modes. Therefore, it is extremely beneficial to develop theoretical approaches that use these resonant states as a physically meaningful basis in order to describe the light–matter interaction in micro- and nanoresonators. However, the question of how to normalize resonant states correctly for such an expansion initially hampered many theoretical attempts. Only recently, this problem of normalization has been solved via different approaches, providing a completely rigorous basis for not only explaining but also quantifying a large variety of resonant phenomena. This review article provides an overview of the related activities in the field and typical applications. We compare the different approaches with a focus on formulations via the Mittag-Leffler expansion of the Green’s dyadic on the complex frequency plane and an analytic normalization scheme for the resonant states. Specifically, we discuss the pole expansion of the near and far field and outline related theoretical tools such as the resonant-state expansion and first-order perturbation theories. These approaches allow for efficiently describing light–matter interaction between local emitters and resonators, scattering of light at nanoparticles, and resonantly-enhanced optical sensing. Moreover, the resulting equations provide insight into the underlying physical mechanisms, which can be used to tailor the light–matter interaction and to predict new phenomena such as the recently observed complex-valued mode volumes. Since the Mittag-Leffler theorem is valid beyond the continuation of physical quantities to the complex frequency plane, an introduction to alternative modal approaches, namely those based on permittivity eigenmodes and propagating modes, is included here as well. While the link of these approaches to resonant phenomena is less obvious, they can be advantageous in some cases. Finally, we show that modal theories can be even applied in nonlinear optics. Hence, the theory of resonant states provides a general theoretical framework in micro- and nanophotonics.
Piezoelectric stick-slip actuator integrated with ultrasonic vibrator for improving comprehensive output performance
Authors: Yang Shitong , Li Yuelong , Qiao Guangda , Ning Peng , Lu Xiaohui , Cheng Tinghai
Published: October 2021

In this paper, a novel compact piezoelectric stick-slip actuator integrated with ultrasonic vibrator based on ultrasonic anti-friction effect is proposed. Based on inverse piezoelectric effect, the piezoelectric stack generates the axial vibration under the excitation of asymmetric sawtooth wave, the ultrasonic vibrator is composed of a brass block and four piezoelectric plates, which is used to excite the ultrasonic longitudinal vibration mode in the fast deformation phase of piezoelectric stack. Due to ultrasonic anti-friction effect, the backward displacement of the actuator is effectively suppressed, and the bidirectional comprehensive output performance is improved. The prototype is fabricated and the operating principle of hybrid excitation is introduced, then the frequency of the first-order longitudinal vibration mode is explored by finite element analysis and impedance test, and the systematic experimental test is conducted. The test results show that when the sawtooth frequency is 300 Hz, comparing with the traditional sawtooth excitation mode, the proposed hybrid excitation mode can improve the velocities of the forward and backward directions by 30% and 26.7%, and the bidirectional maximum vertical mass loads are increased by 44.4% and 50%. This work provides a design concept that uses ultrasonic vibrator to improve the bidirectional comprehensive output performance of the piezoelectric stick-slip actuator.
Evaluation of electrical fatigue limits in REBCO coated conductor tapes through static fatigue testing at 77 K
Authors: de Leon Michael B , Nisay Arman Ray , Shin Hyung-Seop
Published: October 2021

Significant development has been made toward guaranteeing the performance of high-temperature superconducting (RE)Ba2Cu3O7−x
coated conductor (CC) tapes in superconducting devices such as high-field magnets and coils. To understand the superconducting behaviors of CC tapes used in such devices under various mechanical- and thermal-induced loads, their mechanical and electromechanical properties should be evaluated in consideration of their application environments. Under static or cyclic fatigue loads, critical current (I
c) can degrade as a result of damage to the superconducting layer, even under loads that do not exceed the irreversible stress limits for I
c degradation (σ
irr). Therefore, prediction of the stress level that can degrade I
c under various conditions, such as the endurance limit (stress), is significant for actual coil or magnet applications of CC tapes. A static fatigue tester for CC tapes at 77 K was used in this study to apply a static fatigue load to a 12 mm wide GdBa2Cu3O7−x
CC tape specimen under simultaneous axial tension and bending stresses in a U-shaped configuration. Bending mandrels were used to superimpose various bending strains onto the applied static axial tensile strain, and I
c across various voltage tap separations was measured over time, up to 100 h. The electrical static fatigue strength and endurance limit for I
c degradation were determined based on the 95% I
c retention criterion and 100 h of elapsed time, respectively. Results show that bending strain, dependent on mandrel diameter, can greatly influence I
c degradation behaviors and that I
c can drop considerably in the bent sections compared to the straight sections over time. Analyses of the combined strains in the bent sections allowed the prediction of diameter-dependent electrical static endurance limits under subcritical crack growth. The CC tape’s electrical static endurance limit was greatly affected at smaller bending diameters. When CC coils with diameters smaller than or equal to 50 mm are made using 12 mm wide CC tapes, the electrical static endurance limit is low, roughly ⩽0.63σ
irr.
Study of internal porous structure formation of the powder metallurgically prepared aluminium foam
Authors: Gopinathan A , Jerz J , Kováčik J , Dvorák T , Orovčík L
Published: October 2021

The internal pore wall structure formation and density play an important role in improving the mechanical and thermal properties of the closed-cell aluminium foams. The present research work aims to investigate the internal structure formation of the aluminium foam prepared by powder metallurgy and the uniformity of the distribution of the pores when the minimum amount of TiH2 is added. The foamable precursor of two different aluminium alloys (Al-1050 and A5083) is produced with a TiH2 gaseous agent of 0.05 wt.%. The parameters analysed include the density, pore wall formations, pore, and metal density distribution inside the structure with the help of X-ray tomography. Furthermore, the image-processing technique has been adopted to produce the 3D surrogate model of the foam for visual inspection and analysis. The obtained results show the importance of the amount of TiH2 addition and of the foaming furnace temperature in deciding the internal porous structure formation. Further, the pore morphology of lower porosity foams (in the range of 30-40 % porosity) of the two alloys produced at 690 °C furnace temperature is investigated with the help of developed surrogate models. The presence of micropores and uniformity of the distribution of pores found brings the idea of choosing the optimized structure of foam for thermal energy storage systems associated with PCM.
Influence on mechanical behaviors considering construction hosting process of large-scale steel structure
Authors: Fu Y D , Yang S , Li G , Lin X L , Zhang H D , Shang K G
Published: October 2021

In the design of large-scale steel structure, the design calculation of the structure is usually based on the service state. But in the process of steel structure construction, the displacement and stress produced in the construction process cannot be completely consistent with that in the design state. With the progress of construction process, the deformation and stress caused by self-weight and construction load gradually accumulate until the structure is formed, which will produce construction error relative to the design state. In this paper, FEM method was used to simulate the construction process of the steel grid roof of the theater in the Beijing Sub Center Theater project, and the influence of the accumulated deformation and stress on the mechanical properties of the structure during the construction process was analyzed. The results show that the cumulative deformation and stress in the construction process have a great influence on the final deformation and stress distribution of the structure. The maximum vertical displacement in the actual construction state is 599.6% of that in the design state, and the maximum stress is 119.7% of that in the design state. This will lead to the difference between the construction-completed structure and the design structure, which makes the design result dangerous. The measures to optimize the construction process were also given in this paper, which provides guidance for the construction process of large-scale steel structure.
Technoeconomic analysis of High Temperature Reactors for industrial applications in Poland
Authors: Chmielarz B , Bredimas A , Herpson C
Published: October 2021

The paper analyses Polish industrial energy market requirements and the economic boundary conditions of for High Temperature Reactor (HTR)-based hybrid energy systems for electricity, heat, and hydrogen production. The Polish industry suffers from high imported gas prices and high dependence on domestic coal sector. Most industrial coal boilers are ageing and will need replacement within two decades. Increasing emission prices will soon cripple the profitability of coal in favour of natural gas and leave an opening for HTRs. HTRs can be competitive for both heat and electricity generation if used at load factors above 90% and constructed within budget and on time. The competitiveness of HTRs grows further with rising fossil fuels and CO2 emission prices. For industrial hydrogen, steam methane reforming (SMR) is competitive against any other alternative. Large-scale hydrogen production with HTR-based Sulphur Iodine cycle may compete with SMR if capital and operational costs can be decreased. High temperature steam electrolysis requires more durable materials and lower capital cost. Electrolysis, given its relatively low CAPEX and scalability, can be competitive when electricity is cheap as a result of over-production from intermittent power capacities. Other fossil-based hydrogen production methods appear more costly and CO2-intensive than SMR. The study was done as a part of the GEMINI+ project.
Microstructural and Micro-Chemical Evolutions in Irradiated UCO Fuel Kernels of AGR-1 and AGR-2 TRISO Fuel Particles
Authors: Fu Zhenyu , Yang Yong , Van Rooyen Isabella J. , Meher Subhashish , Kombaiah Boopathy
Published: October 2021

AGR-1 and AGR-2 tristructural-isotropic (TRISO) fuel particles were fabricated using slightly different fuel kernel chemical compositions, modified fabrication processes, different fuel kernel diameters, and changed 235U enrichments. Extensive microstructural and analytical characterizations were conducted to correlate those differences with the fuel kernels’ responses to neutron irradiations in terms of irradiated fuel microstructure, fission products’ chemical and physical states, and fission gas bubble evolutions. The studies used state-of-the-art transmission electron microscopy (TEM) equipped with energy-dispersive x-ray spectroscopy (EDS) via four silicon solid-state detectors with super sensitivity and rapid speed. The TEM specimens were prepared from selected AGR-1 and AGR-2 irradiated fuel kernels exposed to safety testing after irradiation. The particles were chosen in order to create representative irradiation conditions with fuel burnup in the range of 10.8 to 18.6% fissions per initial metal atom (FIMA) and time-average volume-average temperatures varying from 1070 to 1287°C. The 235U enrichment was 19.74 wt.% and 14.03 wt.% for the AGR-1 and AGR-2 fuel kernels, respectively. The TEM results showed significant microstructural reconstructions in the irradiated fuel kernels from both the AGR-1 and AGR-2 fuels. There are four major phases: fuel matrix of UO2 and UC, U2RuC2, and UMoC2—in the irradiated AGR-2 fuel kernel. Zr and Nd form a solid solution in the UC phase. The UMoC2 phase often features a detectable concentration of Tc. Pd was mainly found to be located in the buffer layer or associated with fission gas bubbles within the UMoC2 phase. EDS maps qualitatively show that rare-earth fission products (Nd et al.) preferentially reside in the UO2 phase. In contrast, in the irradiated AGR-1 fuel kernel, no U2RuC2 or UMoC2 precipitates were positively identified. Instead, there was a high number of rod-shaped precipitates enriched with Ru, Tc, Rh, and Pd observed in the fuel kernel center and edge zone. The differences in irradiated fuel kernel microstructural and micro-chemical evolution when comparing AGR-1 and AGR-2 TRISO fuel particles may result from a combination of irradiation temperature, fuel geometry, and chemical composition. However, irradiation temperature probably plays a more deterministic role. Limited electron energy-loss spectroscopy (EELS) characterizations of the AGR-2 fuel kernel show almost no carbon in the UO2 phase, but a small fraction of oxygen was detected in the UC/UMoC2 phase.
Intensive Study of Ceria Microsphere Stabilized with Zirconia by The External Gelatin Method
Authors: Ridwan  , Insani A , Mujamilah  , Patriati A , Sulungbudi G T , Rifai M , Sarjono
Published: October 2021

One of the keys to success in the process of fuel synthesis for pebble type high temperature nuclear reactors is mastery in kernel synthesis technology which is the core of the fuel itself. In this paper, the results of a comprehensive study of the preparation of a kernel microsphere from ceria stabilized zirconia (CSZ) using the external gelatin method in BATAN will be discussed. Important parameters obtained from this experiment will be the basis for the actual manufacturing of nuclear fuel kernels. Analysis based on measurement data using the Small Angle Neutron Spectrometer (SANS) provides a deep understanding of the mechanism of CSZ microsphere formation, so that at the end it can provide an understanding of how to avoid possible cracks during heat treatment.
ASME Code Rules and ASTM Standards Integration for Ceramic Composite Core Materials and Components1
Authors: Geringer J W , Katoh Y , Gonczy S , Burchell T , Mitchell M , Jenkins M , Windes W
Published: October 2021

Fiber-reinforced ceramic matrix composites have many desirable properties for high-temperature nuclear applications, including excellent thermal and mechanical properties and reasonable to outstanding radiation resistance. Over the last 20 years, the use of ceramic composite materials has already expanded in many commercial nonnuclear industries as fabrication and application technologies mature. The new ASME design and construction rules under Section III, Subsection HH, Subpart B lay out the requirements and criteria for materials, design, machining and installation, inspection, examination, testing, and the marking procedure for ceramic composite core components, which is similar to the established graphite code under Section III, Subsection HH, Subpart A. Moreover, the general requirements listed in Section III, Subsection HA, Subpart B are also expanded to include ceramic composite materials. The code rules rely heavily on the development and publication of standards for composite specification, classification, and testing of mechanical, thermal, and other properties. These test methods are developed in the American Society for Testing and Materials Committee C28 on Advanced Ceramics with a current focus on ceramic composite tubes. Details of the composites code, design methodology, and similarities to the graphite code, as well as guidance for the development of specifications for ceramic composites for nuclear application and recent standard developments, are discussed. The next step is to “close the gap” to support licensing aspects by validating the code with benchmarking data.
Current Status of Purification of Indonesian Natural Graphite as a Candidate for Nuclear Fuel Matrix by Hydrometallurgy and Pyrometallurgy Methods
Authors: Mustika D , Torowati  , Sudirman  , Dimyati A , Fisli A , Joni I M , Langenati R
Published: October 2021

Indonesia has natural graphite reserved in Sulawesi, Sumatera and Kalimantan islands. The highest graphite content was observed in Sanggau Region, West Kalimantan. Indonesian natural graphite has the potential to be used as fuel matrix in Pebble Bed Reactor (PBR) type - High Temperature Gas Cooled Reactor (HTGR). To increase self-reliance of graphite supply and decrease graphite import for fuel matrix purposes, it is necessary to master the purification technology of graphite. Graphite matrix in Pebble Bed Reactor (PBR) fuel has an important role. It is not only used as neutron moderator and structural material to protect nuclear fuel but also as heat transfer media. Therefore, the graphite matrix must meet the physical and chemical criteria specified for PBR fuel. This paper focuses on current status of purification of Indonesian natural graphite as a candidate for nuclear fuel matrix using hydrometallurgy and pyrometallurgy. Acid and acid mixtures such as HF, HNO3+H2SO4 and HF+HCl+H2SO4 were used for the hydromet-allurgy purification process, while Arc Plasma System were used for pyrometallurgy methods. Characterization for the purified graphite includes physical and chemical properties. The result showed that Indonesian natural graphite obtained from hydrometallurgy was classified into low nuclear grade graphite but it still could be used as nuclear fuel matrix PBR - HTGR. The graphitization degree needs to be increased and the impurity content needs to be decreased for the purified Indonesian graphite using hydrometallurgy method. The Indonesian natural graphite obtained from preliminary pyrometallurgy methods has 96.78 % graphite content according to SEM (surface) observation and the graphite content needs to be increased into nuclear grade graphite.
V&V Methods Used in the Development of FPGA-based I&C Systems for HTR-10
Authors: Maerani R , Suryono TJ , Santoso S , Jung JC
Published: October 2021

Currently, in few countries, there have been many projects related to the development of Field Programmable Gate Array (FPGA)-based Instrumentation and control (I&C) system designs for their nuclear power plant (NPP), whether for modernization or the new development of NPPs. Indonesia already develops a study related to High Temperature Gas Cooled Reactor as the generation IV for NPPs type for these few years with a specific type which is High Temperature Reactor–10 MW (HTR-10). Since the FPGA-based technology is new in the field, and both the international standards and guidance, from national and international has not defined provisions this issue, therefore verification and validation (V&V) activities for this HTR-10 are mandatory to be included in the design life cycle of I&C system development to get license approval from the national regulatory body. The FPGA-based system needs concentration both in hardware and software development, but commonly only software-related standards that usually included in the design and V&V in the previous computer-based I&C system. Therefore, in this study the V&V plan needs to be developed to state the methods to be required regarding the correctness of the applications of FPGA based I&C system. By arranging this V&V method, we will see whether they are easily applicable to actual systems, had the result to reach the requirement to have reliability, availability, maintainability and safety aspects, and has shortened and easier V&V step than computer-based I&C system. From the results of this study, it can be seen that the results of the method used for V&V between Programmable Logic Controller (PLC)-based and FPGA are almost the same because both have almost the same requirements, especially in software design. Some testing is not mandatory for FPGA-based because of the reduced system complexity. The use of FPGA can shorten the V&V process which can also reduce costs.
Recognition Method of Pipeline Damage Degree based on One-dimensional Convolutional Neural Network
Authors: Pu Feiyang , Pan Jianjun , Li Hongren , Feng Qiankui
Published: October 2021

The pipeline is a key component for the transportation of oil, gas, water and other media, and an indispensable part of industrial fluid transportation equipment. In the service process, the pipeline is easily damaged due to fluid erosion, fatigue and other factors. Optical fiber sensing technology has the advantages of high sensitivity, anti-electromagnetic interference, and good corrosion resistance; while deep learning technology has the advantage of automatically extracting data features and classification. This article combines distributed optical fiber sensing technology and deep learning technology to diagnose the degree of damage to the pipeline. This article divides the pipeline damage degree into four types, namely the complete pipeline, 1mm damage, 2mm damage, and 3mm damage. Based on the wavelength division multiplexing demodulation system, the strain time domain signal of the pipeline was collected, and then we independently built a one-dimensional convolutional neural network model, and obtained a recognition accuracy of 95%. Finally, we divided the data into four equal parts and did a four-fold cross-validation, and finally got an average accuracy rate of 85.6%, indicating that the model we designed can better identify the degree of pipeline damage.
RainfallNet: A Dual-Source of Spatial-Channel Attention Fusion Network for Precipitation Nowcasting
Authors: Huang Junhao , Niu Dan , Zang Zengliang , Chen Xisong , Pan Xiaobin
Published: October 2021

Accurate rainfall prediction is conductive to human life and disaster prevention. Meanwhile, deep learning methods are confirmed to be helpful to improve the accuracy of weather prediction. A novel data-driven neural network is proposed in this work referred as RainfallNet which introduces fusion module based on both radar echo observations and numerical weather prediction (NWP) data. The architecture of the network includes three elements: (1) dual encoders to extract the spatio-temporal feature of the radar echo images and NWP data respectively, (2) parallel attention mechanism combining channel attention and spatial attention to reveal the contribution of each data source and (3) combined loss function joining structural similarity loss, mean square error and mean absolute error with different weight for each rainfall level to further increase the meteorologically assessment metrics. The experiments on South China dataset demonstrate the effectiveness of our model, achieving superior performance on meteorologically assessment metrics over most existing algorithms.
An Intra-Pulse Modulation Type Recognition Algorithm for Radar Signals Based on the Improved Residual Network
Authors: Wang Fan , Huang Yifeng , Zhu Ming , Tang Jun , Jia Zhaohong
Published: October 2021

For purpose of solve the problem of poor discrimination and robustness of intra-pulse signal features extracted by the traditional methods, this paper proposes a radar signal intra-pulse modulation type recognition algorithm based on the improved residual network. Firstly, one-dimensional time-domain radar signal is converted into two-dimensional time-frequency image by Smoothing Pseudo Wigner-Ville Distribution; Then the time-frequency image is preprocessed; ResNet-50 network is chosen as the framework. In order to retain the feature map information as much as possible, the convolution kernel is increased in the residual module. The cross entropy loss function and the center loss function are used as the loss function to speed up the convergence of the network. The improved residual network is used to realize the intra-pulse modulation type recognition of radar signal. The simulation experiments show that when the SNR is -14dB, the overall average recognition accuracy of the improved algorithm for eight kinds of radar signals (CM, LFM, NLFM, BLFM, BPSK, QPSK, OPSK, LFM+BPSK) can reach 97.29%, which shows the effectiveness.
The readiness of IoT enabled Smart Buildings in Malaysia
Authors: Kiu Mee San , Chin Ying Jie , Chia Fah Choy , Wong Phui Fung
Published: October 2021

The rapid evolution of the Internet of Things (IoT) has significantly impacted the way of conduct business and influenced current daily lifestyles. Observing this phenomenon, researchers and industry practitioners are increasingly paying attention to the research and development of smart buildings. This research aimed to focus on the readiness of smart buildings in Malaysia and research objectives were set to determine the readiness, potential benefits of implementing smart buildings and the challenges faced in the current state towards adopting smart buildings in Malaysia. Based on the 140 questionnaire survey responses from various construction professionals, descriptive statistics and Kruskal-Wallis test were conducted. This study has contributed to the body of knowledge on understanding on current readiness of Malaysia in the implementation of Smart Building and brought up the main challenges faced towards the adoption of Smart Building. In conclusion, Malaysia has not fully ready to take advantage of the benefits the smart revolution will bring, including greener, safer and more efficient energy use.
Static concentrating photovoltaic modelling using MATLAB
Authors: Muhammad-Sukki Firdaus , Farooq Haroon , Abu-Bakar Siti Hawa , Ardila-Rey Jorge Alfredo , Sellami Nazmi , Kilpatrick Ciaran , Muhtazaruddin Mohd Nabil , Bani Nurul Aini , Zulkipli Muhammad
Published: October 2021

The world has recorded an increasing interest and staggering investment in renewable technology in the last two decades, specifically in solar photovoltaic (PV). Concentrating PV (CPV) is one of PV’s technology advancements and is gaining popularity for integration in a building. Various CPV designs are currently being investigated by researchers. The aim of this paper is to design and develop a MATLAB programme that can predict the electrical properties of a static concentrator that is designed with a ±40° acceptance angle. The programme was utlizied to determine the angular characteristics of the static concentrator between acceptance angle of -50° and 50°. It is proposed that the optoelectronic gain, Copto-evalues be incorporated into the model to simulate a CPV design. The incident angle values (within ±50°) were chosen to demonstrate that the static concentrator could collect solar energy within its designed acceptance angle of ±40°. The current-voltage and power-voltage characteristics are generated for each simulation, and critical parameters such as the maximum power, open-circuit voltage, short-circuit current, and optoelectronic gain were identified and measured. The programme was found to be able to determine the electrical properties for the static concentrator.
Atmospheric trajectory analysis of Cesium-137 from proposed nuclear power plant site in Bangka Island, Indonesia
Authors: Rosli Rafieza , Basri Nor Afifah , Omar Nurlyana
Published: October 2021

Environmental risk assessment for nuclear power plant (NPP) operation is important to monitor the level of radionuclide concentration in the atmosphere and to determine the health risks associated with potential external radiation exposure. A NPP site was proposed in Bangka Island, Indonesia, 554 km from Johor Bahru, Malaysia. In the event of postulated nuclear emergency, the radionuclide dispersion from Bangka Island can possibly arrive in Malaysia’s atmosphere due to its close distance with Malaysian border. The purpose of this study is to assess the trajectories of Cs-137 radionuclide towards Malaysia from Bangka Island NPP site. A simulation was conducted using Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) to describe the movement of radionuclides in the atmosphere from Bangka Island towards Malaysia. The result shows the trajectories and direction of both radionuclides are very much affected by the monsoon season, as well as the meteorological characteristics such as wind speed and direction. In the simulated event of radioactive release in 2019, the trajectories can be seen moving directly towards Malaysia in May, June, July, August, September and October. It is concluded that if Indonesia were to proceed with the NPP construction in Bangka Island, necessary preparation such as emergency plan and risks mitigation should be strategized early in Malaysia to safeguard the public and the environment.
Computational Fluid Dynamics Model of Wells Turbine for Oscillating Water Column System: A Review
Authors: Abdul Settar N. , Sarip S. , Kaidi H.M.
Published: October 2021

Wells turbine is an important component in the oscillating water column (OWC) system. Thus, many researchers tend to improve the performance via experiment or computational fluid dynamics (CFD) simulation, which is cheaper. As the CFD method becomes more popular, the lack of evidence to support the parameters used during the CFD simulation becomes a big issue. This paper aims to review the CFD models applied to the Wells turbine for the OWC system. Journal papers from the past ten years were summarized in brief critique. As a summary, the FLUENT and CFX software are mostly used to simulate the Wells turbine flow problems while SST k-ω turbulence model is the widely used model. A grid independence test is essential when doing CFD simulation. In conclusion, this review paper can show the research gap for CFD simulation and can reduce the time in selecting suitable parameters when involving simulation in the Wells turbine.
Towards the introduction of elements that contribute to the LRT operation sustainability through technology-based ancillary revenue
Authors: Muhamad Pauzi Fazarizul Hashidi , Md Daud Mohd Yusof , Mohamed Ahmad Yusri
Published: October 2021

Transportation and technology innovation is one of the Sustainable Development Goals (SDGs) elements, and it has been outlined in goal number nine. The high demand for LRT usage requires a large amount of electricity. It contributes to the increase in electricity costs that have to be borne by LRT operators, and it is one of the main contributors to the increase in LRT operating costs. Revenue from fares unable to offset the rising operating cost. Therefore, LRT operators need to explore ancillary revenue activities to cover LRT operating costs. This paper aims to identify the elements involved in generating ancillary income through technology-based businesses from fibre optic cable networks along LRT alignment for the LRT operation sustainability. This study adopted semi-structured interviews for data collection and thematic analysis to analyse the data collected to identify the elements involved in generating ancillary revenue. Eleven themes were identified from the thematic analysis using NVivo. The list of elements involved has been proposed in this study has the potential to be a driver in generating ancillary revenue for the sustainability of LRT operations and contribute to sustainable development in achieving one of the objectives outlined in the SDGs.
A versatile and cost-effective automation of an AC susceptometer using Virtual Instruments and Arduino-Uno microcontroller
Authors: Borgohain C. , Borah J.P.
Published: October 2021

A LabVIEWTM based VIRTUAL INSTRUMENT (VI)
system is designed with the aid of an Arduino-Uno microcontroller,
which is used as a data acquisition system for collecting data from
an AC magnetic susceptometer operating in the range of 10 Hz to
10 kHz. The magnetic susceptometer system was indigenously built
using standard modules/components and is capable of measuring AC
magnetic susceptibility from room temperature down to 100 K. The
proposed VI can have diverse applications and may be modified
according to the user requirements. Herein, we have decided to focus
its applicability on the automation of an AC susceptometer
integrated with an inexpensive signal processing unit comprising an
AD630-based lock-in-amplifier and an ICL8038-based signal
generator. Data from the lock-in- amplifier, the signal generator,
and the temperature sensor are interfaced to a computer via an
Arduino-Uno microcontroller. A program (VI) developed using LabVIEW
is used to acquire and record in a PC the data from the AC magnetic
susceptometer.