bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation control for discrete-time multi-agent system with input and output delays under network attacks
Authors: Yuan Jian , Liu Hailin , Zhang Wenxia 
Published: May 2022

AbstractThis paper addresses the mean square consensus-based formation control for multiple agent system (MAS) with input and output delays under network attacks, process noise, and measurement noise in MAS. Firstly, a time delay-free transformation approach for a multi-agent system with input and output delays is presented. The MAS is transformed into a formal delay-free discrete-time system using the delay-free transformation method. Then a state observer based on Kalman filter is presented to estimate the states of agents. A distributed predictive consensus protocol based on the estimated states of each MAS is proposed for the leader-following MAS. The sufficient and necessary conditions of mean square consensus for MAS under DoS attacks are derived. Finally, a numerical example of consensus-based formation control for multi-agent systems is provided to verify the correctness and effectiveness of the proposed consensus control protocol.
SHR1032, a novel STING agonist, stimulates anti-tumor immunity and directly induces AML apoptosis
Authors: Song Chunying , Liu Dong , Liu Suxing , Li Di , Horecny Ivana , Zhang Xinzhu , Li Puhui , Chen Lei , Miller Matthew , Chowdhury Rasheduzzaman , Issa Mena , Shen Ru , Yan Yinfa , Zhang Fengqi , Zhang Lei , Zhang Limin , Bai Chang , Feng Jun , Zhuang Linghang , Zhang Rumin , Li Jing , Wilkinson Hilary , Liu Jian , Tao Weikang 
Published: May 2022

AbstractStimulator of interferon genes (STING) activation induces type I interferons and pro-inflammatory cytokines which stimulate tumor antigen cross presentation and the adaptive immune responses against tumor. The first-generation of STING agonists, cyclic di-nucleotide (CDN), mimicked the endogenous STING ligand cyclic guanosine monophosphate adenosine monophosphate, and displayed limited clinical efficacy. Here we report the discovery of SHR1032, a novel small molecule non-CDN STING agonist. Compared to the clinical CDN STING agonist ADU-S100, SHR1032 has much higher activity in human cells with different STING haplotypes and robustly induces interferon β (IFNβ) production. When dosed intratumorally, SHR1032 induced strong anti-tumor effects in the MC38 murine syngeneic tumor model. Pharmacodynamic studies showed induction of IFNβ, tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) in the tumors and, to a lower extent, in the plasma. More importantly, we found SHR1032 directly causes cell death in acute myeloid leukemia (AML) cells. In conclusion, our findings demonstrate that in addition to their established ability to boost anti-tumor immune responses, STING agonists can directly eradicate AML cells, and SHR1032 may present a new and promising therapeutic agent for cancer patients.
Dynamic simulation and control of the heat supply system of a civic building with thermal energy storage units
Authors: De la Cruz‐Loredo Ivan , Ugalde‐Loo Carlos E. , Abeysekera Muditha 
Published: May 2022

AbstractThe integration of low‐carbon energy solutions into heating and cooling systems is a growing topic of interest towards the decarbonisation of the energy sector. The complexity of interactions between thermal‐hydraulic components in these systems requires moving from a steady‐state analysis to a dynamic approach. Commercial dynamic process simulators provide a good platform to model and simulate the physics phenomena of these components. However, co‐simulation between software engines is often necessary to incorporate process control systems and regulate key system variables. This paper presents the co‐simulation of a real heating application from a civil building for health services integrating thermal energy storage (TES) units. A detailed dynamic model of the heating system under study is developed in Apros, a commercial dynamic process simulator. The process control system responsible for regulating the hydraulic pumps, valves, and heat sources is implemented in MATLAB/Simulink. The TES system is operated by the process control system based on a daily schedule, achieving a reduced utilisation of the heat generation units during peak‐demand hours.
Transfer towards climate neutrality - from LCA to a business case
Authors: Garvens Hans J. 
Published: May 2022

Climate Change Mitigation is high on the agenda. It has been a scientific issues the last years, politics and industry have taken the challenge. Lots of funding and grants are available, engineers are looking into their toolboxes finding some old and many new solutions. We are right at the very start of another industrial revolution – the transfer towards climate neutrality. In the early stages of development many data are still lacking, so LCA might assist to some extent, but not as good as assessing mature industrial processes.
On examples of green steel, synthetic fuels and other carbon capture and utilization (CCU) applications we learned that renewable electricity is the key issue to all decarbonisation or defossilisation projects. No future material processes can greenhouse gas (GHG)-efficiently produce without sufficient build-up of renewable energy capacities including transportation capacities of that energy. The fast build-up of wind and solar power is even more important, than any material or energy carrier process development.
In Life Cycle Assessments assisting the transfer, we should not account for green electricity certificates, if they are bought. Only if new capacities were built up for new electricity demands, decarbonization can be achieved.
Towards social Life Cycle Assessment of Energy Systems: a case study on offshore wind farms from companies’ perspective
Authors: Lehmann Jérémie , Bouillass Ghada , Fofack-Garcia Rhoda , Pérez-López Paula 
Published: May 2022

Within the energy transition context, private and public decision-makers must choose between different energy scenarios. Hence, environmental, and social impacts incurred from the development of renewable energies need to be investigated to ensure their alignment with energy transition objectives.
Social Life Cycle Assessment (S-LCA) is one of the most appropriate methods to analyse social and socio-economic impacts with a life cycle perspective. However, social impacts included in sustainability analyses of energy systems mostly focus on employment or health and safety issues. Few studies in the literature present a rigorous approach to account for social impacts affecting different stakeholder categories.
The present work is supported by a close collaboration with key industrial partners of the energy sector to overcome the above-mentioned limitation. Hence, it contributes to the definition of the goal and scope phase of a S-LCA study through the integration of companies’ perception. Thus, it aimed to highlight the priority of social impact subcategories and related stakeholdersin the context of offshore wind farms (OWF). As a result, a core set of impactcategories that were perceived as the most relevant is proposed.
A molecularly enhanced proof of concept for targeting cocrystals at molecular scale in continuous pharmaceuticals cocrystallization
Authors: Asgarpour Khansary Milad , Shirazian Saeed , Walker Gavin 
Published: May 2022

SignificanceThis contribution offers a proof of concept to make it possible to target a specific (co)crystal at molecular scale within a continuous process. The paper, while addressing a very important issue in public health, i.e., high-efficiency medicine production, also emphasizes the significance of computational material science and data science in generating proper understanding of a process and its optimal operating conditions.
Arbitrary polarization angle and wavefront manipulation of linearly polarized waves using PB phase
Authors: Li GuoQiang , Shi HongYu , Li BoLin , Yi JianJia , Zhang AnXue , Liu HaiWen 
Published: May 2022

Abstract
In this paper, a novel method for the manipulation of linearly polarized (LP) electromagnetic waves using Pancharatnam–Berry phase is proposed. By combining polarization synthesis and aperture phase distributions, the polarization angle and wavefront of an LP wave can be arbitrarily manipulated. Four metasurfaces were designed and fabricated to generate pencil, vortex, and Bessel beams with different polarization angels, respectively. Simulation and measurement results consist well and demonstrate the proposed method in both polarization and wavefront manipulation.
Development of a digital zebrafish phantom and its application to dedicated small-fish PET
Authors: Zvolský M , Schaar M , Seeger S , Rakers S , Rafecas M 
Published: May 2022

Abstract

Objective. We are developing a small-fish positron emission tomography (PET) scanner dedicated to small aquatic animals relevant for biomedical and biological research, e.g. zebrafish. We plan to use Monte Carlo simulations to optimize its configuration and the required water-filled imaging chambers. Our objectives were: (1) to create a digital 3D zebrafish phantom using conventional micro-CT, (2) include the phantom into a simulated PET environment based on the framework GATE, and (3) investigate the effects of the water environment on the reconstructed images. Approach. To create the phantom, we performed ex vivo measurements of zebrafish specimen using a tabletop micro-CT and compared three methods to fixate the specimen. From segmented micro-CT images we created digital emission and transmission phantoms which were incorporated in GATE via tessellated volumes. Two chamber sizes were considered. For reference, a simulation with the zebrafish in air was implemented. The simulated data were reconstructed using CASToR. For attenuation correction, we used the exact attenuation information or a uniform distribution (only water). Several realizations of each scenario were performed; the reconstructed images were quantitatively evaluated. Main results. Fixation in formalin led to the best soft-tissue contrast at the cost of some specimen deformation. After attenuation correction, no significant differences were found between the reconstructed images. The PET images reflected well the higher uptake simulated in the brain and heart, despite their small size and surrounding background activity; the swim bladder (no activity) was clearly identified. The simplified attenuation map, consisting only of water, slightly worsened the images. Significance. A conventional micro-CT can provide sufficient image quality to generate numerical phantoms of small fish without contrast media. Such phantoms are useful to evaluate in-silico small aquatic animal imaging concepts and develop imaging protocols. Our results support the feasibility of zebrafish PET with an aqueous environment.
Using oxygen dose histograms to quantify voxelised ultra-high dose rate (FLASH) effects in multiple radiation modalities
Authors: Van den Heuvel Frank , Vella Anna , Fiorini Francesca , Brooke Mark , Hill Mark , Ryan Anderson , Maughan Tim , Giaccia Amato 
Published: May 2022

Abstract

Purpose. To introduce a methodology to predict tissue sparing effects in pulsed ultra-high dose rate radiation exposures which could be included in a dose-effect prediction system or treatment planning system and to illustrate it by using three published experiments. Methods and materials. The proposed system formalises the variability of oxygen levels as an oxygen dose histogram (ODH), which provides an instantaneous oxygen level at a delivered dose. The histogram concept alleviates the need for a mechanistic approach. At each given oxygen level the oxygen fixation concept is used to calculate the change in DNA-damage induction compared to the fully hypoxic case. Using the ODH concept it is possible to estimate the effect even in the case of multiple pulses, partial oxygen depletion, and spatial oxygen depletion. The system is illustrated by applying it to the seminal results by Town (Nat. 1967) on cell cultures and the pre-clinical experiment on cognitive effects by Montay-Gruel et al (2017 Radiother. Oncol.
124 365–9). Results. The proposed system predicts that a possible FLASH-effect depends on the initial oxygenation level in tissue, the total dose delivered, pulse length and pulse repetition rate. The magnitude of the FLASH-effect is the result of a redundant system, in that it will have the same specific value for a different combination of these dependencies. The cell culture data are well represented, while a correlation between the pre-clinical experiments and the calculated values is highly significant (p < 0.01). Conclusions. A system based only on oxygen related effects is able to quantify most of the effects currently observed in FLASH-radiation.
Fast and memory-efficient reconstruction of sparse Poisson data in listmode with non-smooth priors with application to time-of-flight PET
Authors: Schramm Georg , Holler Martin 
Published: May 2022

Abstract

Objective. Complete time of flight (TOF) sinograms of state-of-the-art TOF PET scanners have a large memory footprint. Currently, they contain ∼4 · 109 data bins which amount to ∼17 GB in 32 bit floating point precision. Moreover, their size will continue to increase with advances in the achievable detector TOF resolution and increases in the axial field of view. Using iterative algorithms to reconstruct such enormous TOF sinograms becomes increasingly challenging due to the memory requirements and the computation time needed to evaluate the forward model for every data bin. This is especially true for more advanced optimization algorithms such as the stochastic primal-dual hybrid gradient (SPDHG) algorithm which allows for the use of non-smooth priors for regularization using subsets with guaranteed convergence. SPDHG requires the storage of additional sinograms in memory, which severely limits its application to data sets from state-of-the-art TOF PET systems using conventional computing hardware. Approach. Motivated by the generally sparse nature of the TOF sinograms, we propose and analyze a new listmode (LM) extension of the SPDHG algorithm for image reconstruction of sparse data following a Poisson distribution. The new algorithm is evaluated based on realistic 2D and 3D simulationsn, and a real data set acquired on a state-of-the-art TOF PET/CT system. The performance of the newly proposed LM SPDHG algorithm is compared against the conventional sinogram SPDHG and the listmode EM-TV algorithm. Main results. We show that the speed of convergence of the proposed LM-SPDHG is equivalent the original SPDHG operating on binned data (TOF sinograms). However, we find that for a TOF PET system with 400 ps TOF resolution and 25 cm axial FOV, the proposed LM-SPDHG reduces the required memory from approximately 56 to 0.7 GB for a short dynamic frame with 107 prompt coincidences and to 12.4 GB for a long static acquisition with 5·108 prompt coincidences. Significance. In contrast to SPDHG, the reduced memory requirements of LM-SPDHG enables a pure GPU implementation on state-of-the-art GPUs—avoiding memory transfers between host and GPU—which will substantially accelerate reconstruction times. This in turn will allow the application of LM-SPDHG in routine clinical practice where short reconstruction times are crucial.
Application of a dual-thermopile radical probe to expanding hydrogen plasmas
Authors: Wang S C , van der Horst R M , van Kampen M , Morgan T W 
Published: May 2022

Abstract
We compare the performance of a hydrogen radical probe to historic data determined via two-photon absorption laser induced fluorescence using a comparable cascaded arc source under similar operating conditions. This probe has dual heat flux sensors (DHFS) each coated with materials with different catalytic properties for hydrogen atoms. In the ideal situation, the hydrogen radical flux can be deduced based on the difference between the heat loads measured by these two sensors. The influence of DHFS temperature on the performance was also assessed. The experimental results showed measurement errors of <10% could be obtained regardless of the probe temperature during plasma exposures. To convert heat fluxes into atomic fluxes, we calibrated the difference of the recombination coefficients using a vacuum ultraviolet absorption technique, which is more reliable than modeled values based on assumptions or scattered values reported in literature. As a result, we measured the hydrogen plasma and radical parameters at various settings using both a double Langmuir probe and the DHFS. The typical atom flux in the 1022 m−2s−1 range was in good agreement with those obtained using optical techniques. We also observed that the ion and atom fluxes are both sensitive to the background gas pressure. These findings validate application of the DHFS to the cascaded arc source, and could pave the way for optimization of the source performance in the plasma material processing experiments.
Improvements of electrical and thermal characteristics for AlGaN/GaN HEMT grown by metal-organic chemical vapor deposition on silicon-on-insulator (SOI) substrate
Authors: Hieu Le Trung , Chiang Chung-Han , Anandan Deepak , Dee Chang-Fu , Hamzah Azrul Azlan , Lee Ching-Ting , Lin Chung-Hsiung , Chang Edward Yi 
Published: May 2022

Abstract
AlGaN/GaN high electron mobility transistors (HEMTs) heterostructures are grown by metal-organic chemical vapor deposition on silicon-on-insulator (SOI) substrate and high-resistivity silicon (HR-Si) simultaneously to investigate the influence of substrate types on electrical and thermal characteristics. The AlGaN/GaN HEMT epitaxial structure grown on SOI achieved high electron mobility (1900 ± 19 cm2 (V s)−1) and high two-dimensional electron gas carrier concentration (9.1 ± 0.1 × 1012 cm−2). The GaN HEMT metal–insulator–semiconductor gate device fabricated on the structure grown on the SOI substrate exhibits higher saturation current and improved buffer breakdown voltage compared with devices fabricated on HR-Si substrate. In particular, SOI substrate helps to improve the thermal-sensitive strain of the GaN-based heterostructure and reduced defect density in the epitaxy, thereby improve the temperature-dependent on-resistance (R
ON) and the dynamic R
ON of the device.
Manufacturing and characterisation of 3D printed thermoplastic morphing skins
Authors: Heeb Rafael M , Dicker Michael , K S Woods Benjamin 
Published: May 2022

Abstract
Morphing aircraft are one promising solution to reducing the aviation industry’s environmental impact because they can make aircraft more aerodynamically efficient, thereby reducing greenhouse gas emissions. The design of morphing skins is inherently challenging due to the competing design constraints of needing to be stiff out-of-plane to resist pressure loads while being compliant in-plane to minimise actuation energy. Previous work by these authors introduced the novel concept of Geometrically Anisotropic Thermoplastic Rubber (GATOR) morphing skins that take advantage of multi-material 3D printing and structural scaling laws to allow for better compromises between these competing design constraints. In this work, multi material Fused Filament Fabrication methods were used to 3D print the proposed GATOR sandwich panels from two different stiffnesses of thermoplastic polyurethane to demonstrate the manufacturing process and experimentally quantify the performance of some simple embodiments of the GATOR concept. The panels were mechanically tested to determine their flexural and extensional stiffnesses. Results show that the panels can be extended to a stretch ratio of λ = 1.6 with a linear response at low stretch ratios. The results from the flexural experiments show that the flexible face sheets are capable of withstanding some compression before buckling, which results in a linear behaviour at small forces. These results show the promise of the GATOR skin concept and motivate future development of designs that further exploit the underlying principles of the concept.
Seeds of phase transition to thermoacoustic instability
Authors: Raghunathan M , George N B , Unni V R , Sujith R I , Kurths J , Surovyatkina E 
Published: May 2022

Abstract
Tackling the problem of emissions is at the forefront of scientific research today. While industrial engines designed to operate in stable regimes produce emissions, attempts to operate them at ‘greener’ conditions often fail due to a dangerous phenomenon known as thermoacoustic instability. Hazardous high amplitude periodic oscillations during thermoacoustic instability lead to the failure of these engines in power plants, aircraft, and rockets. To prevent this catastrophe in the first place, identifying the onset of thermoacoustic instability is required. However, detecting the onset is a major obstacle preventing further progress due to spatiotemporal variability in the reacting field. Here, we show how to overcome this obstacle by discovering a critical condition in certain zones of the combustor, which indicates the onset of thermoacoustic instability. In particular, we reveal the critical value of the local heat release rate that allows us to distinguish stable operating regimes from hazardous operations. We refer to these zones as seeds of the phase transition because they show the earliest manifestation of the impending instability. The increase in correlations in the heat release rate between these zones indicates the transition from a chaotic state to a periodic state. Remarkably, we found that observations at the seeds of the phase transition enable us to predict when the onset occurs, well before the emergence of dangerous large-amplitude periodic acoustic pressure oscillations. Our results contribute to the operation of combustors in more environment-friendly conditions. The presented approach is applicable to other systems exhibiting such phase transitions.
Regional compound humidity-heat extremes in the mid-lower reaches of the Yangtze River: a dynamical systems perspective
Authors: Guo Yixuan , Huang Yu , Fu Zuntao 
Published: May 2022

Abstract
Heat extremes including heatwaves have an adverse impact not only on ecosystems but also on human health. The impact can be seriously exacerbated when both spatial extension and compound factors (such as humidity) are included. However, a unified frame combining compound humidity-heat extremes with their regional extension has received little scientific attention. This study solves this problem by taking the evolution of daily mean 2 m air temperature (Tmean) and relative humidity (RH) over a large domain as two dynamical systems (DSs), then the instantaneous coupling index from the DS method combined with clustering analysis can sort out the regional compound humidity-heat extremes with distinct spatial organized structures. Among them, the compound humidity-heat extremes with dipole Tmean and RH patterns may be missed by the methods based on regional averaging or undiscerned by DS method. Moreover, the mechanisms behind these regional compound humidity-heat extremes with dipole pattern are distinctive on both dynamics and thermodynamics, with a dipole structure found in the atmospheric low-level circulation. These novel findings can contribute considerably to the in-depth understanding on the compound humidity-heat extremes and their mechanisms.