End Station Research Articles

Joint Traffic Routing and Scheduling Algorithm Eliminating the Nondeterministic Interruption for TSN Networks Used in IIoT

Recently, time-sensitive networking (TSN) has been developed to incorporate real-time capabilities to the standard Ethernet for the incompatible issue in existing industrial communication solutions and is considered a promising solution to satisfy the requirements of the Industrial Internet of Things (IIoT). However, the routing and scheduling methods are left out of the TSN standard. This study developed a novel joint traffic routing and scheduling algorithm to compute routes for time-critical flows and construct the schedules. The validity of the proposed algorithm was verified using a random synthetic test scenario. The simulation results demonstrated that the real-time requirements of time-critical traffic could be satisfied with the proposed algorithm. Subsequently, we evaluated the scalability of the proposed algorithm from the perspective of the number of flows that can be scheduled and the network size. The results showed that the computational times for 4000 flows in the realistic industrial network topology and random network topologies (with up to 21 switches and 105 end stations) are at the subsecond level, which indicated the perfect scalability of the proposed algorithm. In addition, compared with the well-known integer linear programming (ILP)-based approach, Degree of Conflict (DoC)-aware iterative routing and scheduling (DA/IRS) approach, and hybrid genetic algorithm (HGA)-based approach, the proposed algorithm is faster than the three approaches by at least an order of magnitude.

An Urban Bus Network Generation Algorithm Based on Particle Swarm Optimization and Force Field Properties

Due to continuous urban sprawl, large-scale bus network design has become a major challenge in urban transport planning. The continuous increase in urban population and scale makes the factors considered in the urban route network design increasingly complex. Contemporary public transportation network design problems are based more on efficiency goals such as the accessibility and comfort of the transportation network, which increases the difficulty of analyzing the problem. Bus network design is not only an NP-hard (nondeterministic polynomial) problem but also a multivariable and multiobjective problem. This paper focuses on the bivariate and multiobjective bus network design problem of route generation and station selection. This paper proposes an algorithm called the Pseudo Force Field. By combining the idea of Particle Swarm Optimization (PSO) and the properties of the force field, a feasible route generation scheme is provided for the design of the bus network. The algorithm does not need to determine the end station and has a high degree of completion of the demand. This solves the problem of the selection of terminal stations in large-scale road network design. On this basis, the article combines Genetic Algorithm (GA) and Pareto frontier to provide a new route optimization algorithm and proves the effectiveness of the algorithm. The model has achieved theoretical results in the design of the bus route network in the megacity of Shenzhen, China.

Integrated optimization of charger deployment and fleet scheduling for battery electric buses

• An integrated optimization model is developed for BEBs under opportunity charging. • Both charger deployment and fleet scheduling are optimized in the proposed model. • The system behavior in response to a group influencing factors are explored. • The cost-effective advantage of opportunity charging for BEB system is evaluated. Battery electric buses (BEBs) are considered effective options for sustainable mobility. Their operational efficiency is significantly influenced by the deployment of charging infrastructure and the scheduling of the bus fleet. In this research, we develop an integrated optimization model for charger deployment and fleet scheduling for BEBs under opportunity charging. The model jointly optimizes the battery nominal capacity, bus fleet size, and charger deployment at bus stops and the central terminal to minimize the total annualized costs. The time-varying characteristics of ridership, dwelling time, and travel time are considered to investigate realistic solutions with opportunity charging supplied by pantograph chargers. A real-life case study conducted in Oslo, Norway is presented to demonstrate the proposed model, and accordingly sensitivity analysis is further carried out to evaluate the system responses to a group of impact factors. The results indicate that BEB purchase costs and energy consumption rate have significant impacts on total annualized costs, and also imply that opportunity charging has a cost-effective advantage, which can save up to 13.38% of total annualized costs as compared to end station charging using the same type of pantograph charger.

Digging deeper: Buried layers and interfaces studied by modified total electron yield and soft x-ray absorption spectroscopy

We report on the soft x-ray absorption spectroscopy investigation of thin film capacitors using a modified total electron yield detection mode. This mode utilizes two ammeters instead of one as commonly employed in the classical total electron yield scheme to measure photocurrents of devices under soft x-ray irradiation. The advantage of this configuration over the surface sensitive classical total electron yield mode is that it can provide information from buried layers and interfaces up to a thickness equal to the penetration depth of soft x-rays. The method can be easily adapted to existing synchrotron end stations. We investigate dielectric capacitors with dissimilar electrodes to assess the feasibility of the modified total electron yield method. Furthermore, in operando soft x-ray absorption spectroscopy measurements are performed on ferroelectric capacitors under bias and using two ammeters. The experimental results are discussed in terms of the external and internal photoemission processes and their distribution in thin film capacitors under an external bias condition. The proposed detection method opens the way to perform electronic and chemical state analyses of the buried interfaces and layers in various devices like multiferroic tunnel junctions, memristive devices, etc., during operation under an applied bias.

Measurement of Low-Energy Resonance Strengths in the O18(α,γ)Ne22 Reaction

The ^{18}O(α,γ)^{22}Ne reaction is an essential part of a reaction chain that produces the ^{22}Ne(α,n)^{25}Mg neutron source for both the weak and main components of the slow neutron-capture process. At temperatures of stellar helium burning, the astrophysically relevant resonances in the ^{18}O(α,γ)^{22}Ne reaction that dominate the reaction rate occur at α particle energies E_{lab} of 472 and 569 keV. However, previous experiments have shown the strengths of these two resonances to be very weak, and only upper limits or partial resonance strengths could be obtained. This Letter reports the first direct measurement of the total resonance strength for the 472- and 569-keV resonances, 0.26±0.05 and 0.63±0.30 μeV, respectively. New resonance strengths for the resonances at α particle energies of 662.1, 749.9, and 767.6 keV are also provided. These results were achieved in an experiment optimized for background suppression and detection efficiency. The experiment was performed at the Sanford Underground Research Facility, in the 4850-foot underground cavity dedicated to the Compact Accelerator System for Performing Astrophysical Research. The experimental end station used the γ-summing High EffiCiency TOtal absorption spectrometeR. Compared to previous works, the results decrease the stellar reaction rate by as much as ≈46_{-11}^{+6}% in the relevant temperature range of stellar helium burning.

Ion beam tools for nondestructive in-situ and in-operando composition analysis and modification of materials at the Tandem Laboratory in Uppsala

Ion accelerators have demonstrated tremendous versatility in their research applications throughout several decades. Starting predominantly as nuclear physics tools, they subsequently provided novel insights into fundamental atomic physics. Nowadays small and medium size accelerators are routinely employed in several branches of materials science. As research questions increasingly drive the need for analyses and material modification experiments performed in-situ and/or in-operando, facilities must adapt to service such a need. In this work, we highlight capabilities for in-situ and in-operando composition depth profiling and materials modification, developed with instrumentation at the Tandem Laboratory at Uppsala University. An overview of available ion sources and accelerators is given. We then exemplify the specific capabilities of the available end stations for materials synthesis, sample modification and device operation either during simultaneous ion beam based characterization or with such characterization performed in-situ before and after the application of various modification steps. Describing specific recent examples and potential future applications, we illustrate the impact of the present national research infrastructure.

Infrared free-electron laser irradiation of carbon dioxide ice

Interstellar ice grains are believed to play a key role in the formation of many of the simple and complex organic species detected in space. However, many fundamental questions on the physicochemical processes linked to the formation and survival of species in ice grains remain unanswered. Field work at large-scale facilities such as free-electron lasers (FELs) can aid the investigation of the composition and morphology of ice grains by providing novel tools to the laboratory astrophysics community. We combined the high tunability, wide infrared spectral range and intensity of the FEL beam line FELIX-2 at the HFML-FELIX Laboratory in The Netherlands with the characteristics of the ultrahigh vacuum LISA end station to perform wavelength-dependent mid-IR irradiation experiments of space-relevant pure carbon dioxide (CO2) ice at 20 K. We used the intense monochromatic radiation of FELIX to inject vibrational energy at selected frequencies into the CO2 ice to study ice restructuring effects in situ by Fourier Transform Reflection–Absorption Infrared (FT-RAIR) spectroscopy. This work improves our understanding of how vibrational energy introduced by external triggers such as photons, electrons, cosmic rays, and thermal heating coming from a nascent protostar or field stars is dissipated in an interstellar icy dust grain in space. Moreover, it adds to the current literature debate concerning the amorphous and polycrystalline structure of CO2 ice observed upon deposition at low temperatures, showing that, under our experimental conditions, CO2 ice presents amorphous characteristics when deposited at 20 K and is unambiguously crystalline if deposited at 75 K.

Strain-Assisted Single Pt Sites on High-Curvature MoS 2 Surface for Ultrasensitive H 2 S Sensing

Strain-Assisted Single Pt Sites on High-Curvature MoS ₂ Surface for Ultrasensitive H ₂ S Sensing

Design and stability performance of a cradle type cryo-cooled monochromator at Shanghai Synchrotron Radiation Facility

The mechanical design and stability performance of a dedicated double crystal monochromator (DCM) which has been commissioned in beamline BL02U2 at Shanghai Synchrotron Radiation Facility are presented. Details of the cradle type crystal angular adjustment mechanism design is given. The vibration response and relative stability performance of the DCM are systematically investigated at ambient temperature and under liquid nitrogen circulation condition respectively, whose vibrational spectra analyses coincide with each other highly. Furthermore, the X-ray beam stability at sample position is performed by a quadrant CVD-diamond beam position monitor (QBPM) in the end station. In summary, the dedicated monochromator achieves a relative pitch vibration of 31.5 nrad (Root-Mean-Square, RMS) in 0.1-100 Hz bandwidth at the liquid nitrogen (LN2) flow rate of 2.4 L min −1, which is of a good stability performance.

Enhanced thin film analysis via High Resolution RBS using the NEC CARBS system

Advancements in thin film deposition techniques can now produce films of only a few monolayers in thicknesses, with multiple applications emerging in the nano technology field. This maturing manufacturing technique is driving the need for diagnostics tools able to accurately measure depth profiles. To meet this need, the Compact Automated Rutherford Back-Scattering (CARBS) system is under development at National Electrostatics Corp. (NEC) for nanometer thin film analysis using High-resolution RBS (HRBS) within a 4 x 4meter footprint. We present the recent development of the system and demonstrate a study of HRBS applied to a 30nm CoAl alloy film. We compare the performance of the CARBS system with the conventional NEC HRBS end station and discuss the advantages of HRBS over SIMS method.

Application Layer ARQ Algorithm for Real-Time Multi-Source Data Streaming in UAV Networks.

Because of the specific characteristics of Unmanned Aerial Vehicle (UAV) networks and real-time applications, the trade-off between delay and reliability imposes problems for streaming video. Buffer management and drop packets policies play a critical role in the final quality of the video received by the end station. In this paper, we present a reactive buffer management algorithm, called Multi-Source Application Layer Automatic Repeat Request (MS-AL-ARQ), for a real-time non-interactive video streaming system installed on a standalone UAV network. This algorithm implements a selective-repeat ARQ model for a multi-source download scenario using a shared buffer for packet reordering, packet recovery, and measurement of Quality of Service (QoS) metrics (packet loss rate, delay and, delay jitter). The proposed algorithm MS-AL-ARQ will be injected on the application layer to alleviate packet loss due to wireless interference and collision while the destination node (base station) receives video data in real-time from different transmitters at the same time. Moreover, it will identify and detect packet loss events for each data flow and send Negative-Acknowledgments (NACKs) if packets were lost. Additionally, the one-way packet delay, jitter, and packet loss ratio will be calculated for each data flow to investigate the performances of the algorithm for different numbers of nodes under different network conditions. We show that the presented algorithm improves the QoS of the video data received under the worst network connection conditions. Furthermore, some congestion issues during deep analyses of the algorithm’s performances have been identified and explained.

The Ice Chamber for Astrophysics-Astrochemistry (ICA): A new experimental facility for ion impact studies of astrophysical ice analogs.

The Ice Chamber for Astrophysics-Astrochemistry (ICA) is a new laboratory end station located at the Institute for Nuclear Research (Atomki) in Debrecen, Hungary. The ICA has been specifically designed for the study of the physico-chemical properties of astrophysical ice analogs and their chemical evolution when subjected to ionizing radiation and thermal processing. The ICA is an ultra-high-vacuum compatible chamber containing a series of IR-transparent substrates mounted on a copper holder connected to a closed-cycle cryostat capable of being cooled down to 20K, itself mounted on a 360° rotation stage and a z-linear manipulator. Ices are deposited onto the substrates via background deposition of dosed gases. The ice structure and chemical composition are monitored by means of FTIR absorbance spectroscopy in transmission mode, although the use of reflectance mode is possible by using metallic substrates. Pre-prepared ices may be processed in a variety of ways. A 2 MV Tandetron accelerator is capable of delivering a wide variety of high-energy ions into the ICA, which simulates ice processing by cosmic rays, solar wind, or magnetospheric ions. The ICA is also equipped with an electron gun that may be used for electron impact radiolysis of ices. Thermal processing of both deposited and processed ices may be monitored by means of both FTIR spectroscopy and quadrupole mass spectrometry. In this paper, we provide a detailed description of the ICA setup as well as an overview of the preliminary results obtained and future plans.

Using In Situ Synchrotron‐Radiation‐Based Microtomography to Investigate 3D Structure‐Dependent Material Properties of Tension Wood

Synchrotron‐radiation‐based microtomography enables the 3D analysis of biological samples in situ beyond simple visualization, providing accurate measurements and recording of temporal data. The microtomography end station at P05 (PETRA III, Hamburg, Germany), operated by the Helmholtz Zentrum Hereon, can accommodate complex sample environments such as a load frame for mechanical testing. Herein, the strain analysis of a volumetric time series dataset of small hardwood samples is presented. For this in situ mechanical testing, the load frame is operated in tensile mode, and the biogenic material samples are subdivided into those specialized for tensile forces and those of regular anatomical structure. Digital volume correlation analysis allows for the prediction of strain development at any position in the sample. The tissue specialized for tensile strength can align dislocations formed under tension such that the deformation is stronger and more ordered. The results show how high‐resolution imaging of sequential loading and the subsequent localization of strain can reveal functional morphological relationships. These methods can be extended to other biological materials and may prove to be extremely relevant for the analyses of fibrous and/or layered composite materials.

Characteristics of the social network of bike share members in New York City

BackgroundBike share has been hypothesized to be a phenomenon of social contagion. The current study describes the features of the social network of annual subscribers of the Citi Bike share system in NYC and the characteristics of those who ever took a trip with another member. MethodsAssociations comparing members who rode with others (social) to those who rode alone (non-social) on selected study variables were examined. Social network analysis was performed to examine characteristics of the network of Citi Bike members. A social trip was determined based on start and end trip time and station locations. ResultsThere were 241,340 active Citi Bike members with at least 365 days of membership between May 13, 2013 and December 31, 2018. Those who had taken at least one social trip (n = 139,302, 57.7%) were more likely to be older; have higher household income; have ridden a bike in NYC 12 months before membership; not own a car; self-report as physically active; self-report good health; live in a ZCTA with a Citi Bike station; and list primary reasons for membership as a faster way to get around town or as friends and family joining. Those who never took a social trip were more likely to have requested safety tips from Citi Bike; and to report their primary reason for membership as an alternative to public transportation, personal health and fitness, or support for the program. The social network of Citi Bike members was composed of 139,302 members with 164,735 unique connections to other members. The average number of connections per social member was 2.4 and the maximum was 66. The network was not very dense or well connected with 19,809 subnetworks. ConclusionSocial members differed from non-social members in several ways. Understanding the characteristics of key network members could play a part in promoting and encouraging bike share usage. In particular, organized social trips could increase bike share usage among women.

A study of the formation of isotopically pure 28Si layers for quantum computers using conventional ion implantation

We have investigated the use of conventional ion implantation to fabricate enriched 28Si layers for use in quantum computers. The final compositions of samples enriched using ultra-low energy (ULE) (800 eV and 2 keV) and low energy (20 keV) 28Si implants of varying fluences (1 × 1016–3.8 × 1017 cm−2) using two different implanters were measured using channelled Rutherford Backscattering Spectroscopy (RBS). The dynamic, binary collision approximation program TRIDYN was used to model the implantation profiles to guide the analysis of the RBS spectra. It was found that ULE implants achieved high 28Si enrichment levels but were heavily contaminated with oxygen due to poor vacuum in the implanter wafer end station. It was shown that oxidation could be reduced by using an accelerator with an end station with better vacuum and increasing the implant energy to 20 keV. However, TRIDYN simulations predict that the best 28Si enrichment levels that could be achieved under these conditions would saturate at ∼99.2% due to self-sputtering. We modelled a range of conditions with TRIDYN and so recommend low energies (<3 keV), ultra-high vacuum implantation for high 28Si enrichment (>99.9%) with the lowest possible fluences (∼5–10 × 1017 cm−2).

Energy recovery operation for continuous-wave X-ray free-electron lasers

A superconducting linear accelerator operating in continuous-wave mode could produce X-ray free electron lasers (XFEL) at megahertz repetition rate, with the capability that delivering wide spectral range coherent radiation to multi end stations. In this paper, the energy recovery Linac (ERL) mode is proposed to flexibly control the electron beam energy for a continuous-wave superconducting Linac. Theoretical investigations and multi-dimensional numerical simulations are applied to the Linac case of Shanghai high-repetition-rate XFEL and extreme light facility. The results show that, with ERL operation in the last 25 cryo-modules, the strict requirements on RF power system could be significantly relaxed. And if one exhaust the RF power, the maximum electron beam energy can be enhanced from 8.74 GeV to 11.41 GeV in ERL mode. The optimization of the ERL operation, the multi-energy electron beam transport and the XFEL performance improvements are presented.

The first experimental results from the 04BM (PEEM/XAS) beamline at Solaris

The spectroscopy using synchrotron radiation is the advanced tool for materials characterization. In the current work we are reporting recent activity in this research field implemented at the 04BM (PEEM/XAS) beamline of the National Synchrotron Radiation Centre SOLARIS in Krakow, Poland. The beamline is designed to cover wide energy range of soft X-rays, which is well suited for a broad range of applications, including surface physics, material science and magnetism. The comparison of the experimental parameters and selected examples of the results achieved on the PEEM and XAS end stations is demonstrated.

New Records of Amplypterus Hübner and Marumba Moore (Lepidoptera: Sphingidae) from Catanduanes Island, with a Checklist of the Species Known from the Philippines

New island records in the Philippines for two hawkmoths, Amplypterus panopus mindanaoensis and Marumba amboinicus luzoni, are presented together with a checklist (including synonyms) of congeners recorded in the country. The species were found in the vicinity of the 69KV NAPOCOR Power Load End Station in Codon, San Andres, Catanduanes, increasing the number of hawkmoth species record from the island to three. To date, Catanduanes still has a very low species count compared to other islands of the Philippine archipelago. Thus, further exploration and studies on hawkmoths should be conducted.

Inelastic background modelling applied to hard X-ray photoelectron spectroscopy of deeply buried layers: A comparison of synchrotron and lab-based (9.25 keV) measurements

Hard X-ray Photoelectron Spectroscopy (HAXPES) provides minimally destructive depth profiling into the bulk, extending the photoelectron sampling depth. Detection of deeply buried layers beyond the elastic limit is enabled through inelastic background analysis. To test the robustness of this technique, we present results on a thin (18 nm) layer of metal–organic complex buried up to 200 nm beneath organic material. Overlayers with thicknesses 25–140 nm were measured using photon energies ranging 6–10 keV at the I09 end station at Diamond Light Source, and a new fixed energy Ga Kα (9.25 keV) laboratory-based HAXPES spectrometer was also used to measure samples with overlayers up to 200 nm thick. The sampling depth was varied: at Diamond Light Source by changing the photon energy, and in the lab system by performing angle-resolved measurements. For all the different overlayers and sampling depths, inelastic background modelling consistently provided thicknesses which agreed, within reasonable error, with the ellipsometric thickness. Relative sensitivity factors were calculated, and these factors consistently provided reasonable agreement with the expected nominal stoichiometry, suggesting the calculation method can be extended to any element. These results demonstrate the potential for the characterisation of deeply buried layers using synchrotron and laboratory-based HAXPES.

Radiation shielding analysis of the small-angle X-ray scattering flight tube end station of APS upgrade project

The CSSI beamline of the APSU will have a 20.5 m long, 2.75 m diameter SS end station designed to accept pink beam. The radiation shielding analysis of this end station is analyzed here using STAC8 and FLUKA codes. Effect of mirror properties such as reflectivity, coating, inclination and roughness as well as variation in the steel composition are also studied. 8 mm thick SS is found to be adequate if the source is defined by a pinhole and the white beam is reflected with two mirrors inclined at 3.0 mradian or more. The dose rates from monochromatic beams are found to be below the desired levels when the XOP calculated bandwidth (BW) are used while the use of a flat 0.1% BW requires the mirror inclinations to be above 2.5 mradian or more. STAC8 results are consistently higher than the FLUKA results by about 1.5–2.0 times.