bluuebunny/crossref_metadata_2025 huggingface dataset:
Vacuum design of the Super-FRS at FAIR
Authors: Kurichiyanil N , Bergmann A , Karagiannis C , Kraemer A , Kurdal J , Mai B , Purushotaman S , Weick H , Winkler M
Published: January 2024

The large-acceptance superconducting fragment separator (Super-FRS) poses unique challenges for its beam and insulation vacuum systems. These systems must operate in high radiation environments and accommodate dynamically changing experimental setups. Although the vacuum levels ranging from 10−5 to 10−7 mbar required by this single-pass machine are not particularly demanding, several factors make the design of the vacuum systems challenging. These include highly outgassing and self-sealing inserts, large volumes not typically encountered in accelerator beamlines, and a high level of prompt and residual radiation in the target and pre-separator area. In this article, an overview of the Super-FRS vacuum design is presented and handling of the standard and special vacuum components in the system is discussed.
Research on hydrostatic leveling system to provide elevation constraints for control network adjustment
Authors: Li X , He X Y , Wang W , Cheng Z B , Wu E C , Zhang Q Y , Ding T
Published: January 2024

As the precise sensor system for monitoring the relative altitude changes among multiple points, the capacity hydrostatic leveling system (HLS) is widely used in particle accelerators. To expand its application in providing the elevation constraint for the control network adjustment, the research on the issue of the HLS for altitude difference measurement between multiple points is carried out. Based on the working principle of the HLS sensor, a comparison system composed of dual-frequency laser interferometer, high-precision Z stage, HLS sensors and others is designed and manufactured. The system is used to control multiple sensors to observe the same liquid level in the same coordinate system. The zero-position difference among sensors can be obtained by comparison. Then the altitude difference measurement can be realized, and it is verified that the measurement accuracy is better than 5 μm. In addition, a simulation experiment for 3D control network measurement is run, in which the HLS system provides the elevation constraint for the adjustment processing. The results show that for the 100m linear tunnel, the errors accumulation in the elevation direction is significantly improved compared to the classics adjustment.
Assessment of beam-intercepting device robustness for intensity increase in CERN’s North Area
Authors: Sharp C J , Francia A Romero , Ximenes R Franqueira , Calviani M , Grenard J-L , Mazzola G , Esposito L S , Bernhard J , Mazuecos A Lafuente , Galan F Sanchez , Lazzaroni M , Brugger M , Ramjiawan R L , Fraser M A
Published: January 2024

CERN’s North Area comprises several target and experimental systems and is a zone of interest for future development. Provision of beam to this area relies upon several beam-intercepting devices located in various branched transfer lines from the Super Proton Synchrotron. In several lines, these include a primary production target system of beryllium plates followed by a combined collimation, attenuation and dump device made from a set of aluminum, copper and iron blocks and known as a ‘TAX’ (Target Attenuator [for] eXperimental areas). These may operate in a range of configurations depending on experimental needs. Future operational regimes with higher beam intensities (increased from a current specification of 1.5× 1013 to 4.0× 1013
p
+/pulse), shorter pulse times (4.8 s reduced to 1.2 s), greater repetition rates (14.4 s cycle time reduced to 7.2 s) and ten times the annual intensity place more stringent thermo-structural demands on these existing devices, beyond their original specification. This contribution outlines the engineering analysis, including beam-matter interaction studies and thermo-structural simulations, carried out to assess their robustness under such conditions.
Electromagnetic design of 402 MHz normal conducting coaxial window for SNS facility
Authors: Pronikov A I , Agustsson R , Kang Y , Kutsaev S V , Lee S W , Moss J , Smirnov A Y , Thielk S U
Published: January 2024

RadiaBeam has developed a novel design of MW-class high-power RF windows to be used in high-power proton accelerators, such as SNS. This design is based on the utilization of a coaxial window between two waveguides to coaxial transitions, instead of a ceramic window in a uniform cylindrical waveguide, which provides several significant benefits. In this paper, we will present the RF and engineering design of this window.
Conceptual design of a super bend dipole magnet as a high-field source for the ILSF storage ring
Authors: Ehsanizadeh M , Saeidi F , Khorsandi M , Noori K
Published: January 2024

The Iranian Light Source Facility (ILSF) is in the detailed design phase. It will operate at 3 GeV and 400 mA with an ultra-low horizontal emittance of 0.27 nm.rad. The main storage ring combined dipole magnet has a 0.56 T magnetic field and a -7 T/m gradient. It can serve as a soft X-ray source. There are several ways to achieve hard X-rays; one is to use a high-field dipole. It is designed with a permanent magnet and consists of three parts; a high field part that provides a 3 T magnetic field and two low field parts on either side of the high field one. The basic design of the super-bend dipole magnet is presented here.
Evaluation of low-loss alumina material for high-power RF windows
Authors: Thielk S U , Agustsson R , Carriere P , Kutsaev S V
Published: January 2024

Conventional RF vacuum windows are made of metalized ceramics, hermetically brazed to a pillbox cavity. High-power windows, operating in ultra-high frequency (UHF) band, require the fabrication of ceramic disks with diameters on the order of 9”. Furthermore, a Titanium Nitride (TiN) multipactor suppression coating must be applied to the ceramic surfaces. The large size and complex internal geometry of these windows create challenges in validating the coating in the fully fabricated assembly. This study evaluates a novel low-loss alumina AO479U, provided by Kyocera, and a reactive sputtering process suitable to deposit a 10-20 nm thick TiN coating on a large diameter window. The paper will report the changes in the TiN coating through chemical cleaning and vacuum braze processes using stylus profilometry, optical microscopy, Scanning Electron Microscopy (SEM), and Rutherford Backscattering Spectroscopy (RBS).
Beam-Beam Long Range Compensator Mechanical Demonstrator
Authors: Sito L. , Accettura C. , Bertarelli A. , Carra F. , Garlaschè M. , Gentini L. , Valenzuela J. Guardia , Guinchard M. , Hoell S. , Motschmann F. , Papaphilippou Y. , Rossi A. , Sacristan de Frutos O. , Sterbini G.
Published: January 2024

Beam-Beam Long-Range Compensators employing current-carrying wires are considered as valuable options in hadron colliders to increase dynamic aperture at small crossing angles. This paper presents a simple design proposal for application at CERN LHC. The preliminary design allows for a certain scalability of the number of modules, current flowing in the wire, and dimensions. It complies with two key requirements: (a) the use of a thin, bare metal wire that allows for movement as near to the beam as necessary while minimizing interactions with beam particles and meeting the specified DC current target; and (b) a wire support that is both an electrical insulator and a thermal conductor (ceramic). A molybdenum wire, vacuum brazed on an aluminium nitride support, is proposed, and the design is conceptually proved through the realization and extensive test of a demonstrator device. The wire brazing validation, as well as the system’s heat management, which are the most critical aspects, are given particular regard.
Evaluation of green laser source additive manufacturing technology for accelerator applications with ultra-high vacuum requirements
Authors: Ratkus A , Rarison S , Garion C , Kos H , Gruber S , Stepien L , Patil A. A. , Lopez E , Torims T , Pikurs G , Vedani M , Lacis V
Published: January 2024

Additive Manufacturing (AM) offers different benefits such as efficient material usage, reduced production time and design freedom. Moreover, with continuous technological developments, AM expands in versatility and different material usage capabilities. Recently new energy sources have been developed for AM – green wavelength lasers, which provide better energy absorption for pure copper. Due to high thermal and electrical conductivity of copper, this novel AM technology is highly promising for various industries, particularly, there is a huge interest to use it for accelerator applications. In particular, these AM produced accelerator components should reach the associated Ultra High Vacuum (UHV) requirements. In this study, vacuum membranes of pure copper were produced by AM using a green laser source, in different thicknesses and built angles. Furthermore, a vacuum membrane helium leak tightness test was performed at room temperature by using a high-sensitivity mass spectrometer. Comparison of these test results was performed with previously established results. Through this study, novel knowledge and initial results are provided for green laser source AM technology usage for applications for UHV accelerator components.
Plasma Cleaning of Hydrocarbon and Carbon Contaminated Surfaces of Accelerator Components
Authors: Giordano M C , Pinto P Costa , Henrist B , Himmerlich M , Taborelli M , Thaus N , Carlino V , Fahey M , Monteiro J , Tran L
Published: January 2024

To achieve the vacuum quality required for the operation of particle accelerators, the surface of the vacuum vessels must be clean from hydrocarbons. This is usually achieved by wet chemistry processes, e.g., degreasing chemical baths that, in case of radioactive vessels, must be disposed accordingly. An alternative way exploits the oxygen plasma produced by a downstream RF plasma source. This technique offers the possibility of operating in-situ, which is an advantageous option to avoid the handling of voluminous and/or fragile components and a more sustainable alternative to large volume disposable baths. In this work, we test a commercial plasma source in dedicated vacuum systems equipped with quartz crystal microbalances (QCMs). The evolution of the etching rates of amorphous carbon (a-C) thin films deposited on the QCMs to mimic contamination are studied as function of operating parameters. We present the results of the plasma cleaning process applied to the real case of a hydrocarbons-contaminated large vacuum vessel. The studies are complemented by transport simulations and surface contamination monitoring by X-ray photoelectron spectroscopy (XPS) analysis. The evaluation of the vessel cleanliness, which is performed via residual gas analysis (RGA) measurements, is based on CERN’s outgassing acceptance criteria and agrees with both simulations and XPS results.
Innovations in the Next Generation Medical Accelerators for Therapy with Ion Beams
Authors: Benedetto E , Vretenar M
Published: January 2024

Modern hadron-therapy accelerators have to provide high intensity beams, for innovative dose-delivery modalities such as FLASH, pencil beams for 3D scanning, as well as multiple ions with radio-biological complementarity. They need to be compact, cheap and have a reduced energy footprint. At the same time, they need to be reliable, safe and simple to operate. Cyclotrons and compact synchrotrons are nowadays the standard for proton therapy. For heavier ions such as carbon, synchrotrons remain the most viable option, while alternative solutions based on linacs, FFAs or cyclotrons are being proposed. In this context, the European project HITRIplus studies the feasibility of an innovative super-conducting (SC) magnet synchrotron for carbon ions, with state-of-the-art multi-turn injection from a specially designed linac and advanced extraction modalities. A compact synchrotron optimized for helium ions, making use of proven normal-conducting technology, is also being designed.
Cryogenic oxygen deficiency hazard assessment at the National Synchrotron Radiation Research Center
Authors: Kao S P , Wen P J , Lin Y C
Published: January 2024

The National Synchrotron Radiation Research Center (NSRRC) uses cryogenic fluids to create a low-temperature cooling environment for equipment and to conduct various experiments. However, exposure to these cryogenic fluids can cause frostbite, hypoxic suffocation, behavioral incapacitation, insanity, and even death in severe cases. To evaluate oxygen deficiency hazard (ODH) in the NSRRC, we adopted the Fermilab assessment methodology and conducted ODH assessments in the Cryogenic Compressor Room, Taiwan Light Source (TLS) Tunnel, and TLS15A hutch. The results of the evaluation of the Cryogenic Compressor Room and TLS Tunnel revealed that the ODH class is 0 both when the exhaust fan is operating normally and when the exhaust fan is damaged. The exhaust equipment in the TLS15A hutch is only for emergency use. Without the emergency exhaust fan, the ODH class in the area is 1. If the emergency exhaust fan is always on, the ODH class is 0. Therefore, we recommend that those in TLS15A should undergo safety education and receive hazard notifications. In addition, we strongly recommend installing oxygen detectors in the beamline hutch to ensure safety.
Experimental validation of Monte Carlo simulation model for X-ray security scanner
Authors: Park Junsung , An Geunyoung , Yoon Seonkwang , Seo Hee
Published: January 2024

Transmission X-ray security scanners are deployed to detect smuggling of contraband
articles, including weapons, narcotics, and explosives, for the purposes of homeland
security. Current X-ray scanners use a fixed tube voltage (i.e., 160 kV); hence, they have a
limitation in detecting thinly coated and/or low-density objects. To overcome this limitation, we
are developing an X-ray scanner that applies variable tube voltage according to the
physical/chemical properties of the object being inspected. To this end, in our previous study,
Monte Carlo simulations with Geant4 (GEometry ANd Tracking4) and MCNP (Monte Carlo N Particle)
were performed to optimize the design of the X-ray scanner for variable tube voltages. The MCNP
was used to simulate the radiation generator for the X-ray source term, and the Geant4 was used to
optimize the design of the dual-energy detector and to obtain the detector counts. In the present
study, we experimentally validated the reliability of the Monte Carlo simulation model for the
X-ray scanner. An 241Am source and a radiation generator were employed in this
validation. For the 241Am source, the dual-energy detector signal was measured
at a distance of 1 cm from the detector. In the case of the radiation generator, the
source-to-object distance and the source-to-detector distance were 70 cm and 120 cm, respectively,
as used in a typical X-ray security scanner. The tube voltage and the current were 140 kV and 10 mA, respectively. To obtain the X-ray images, the object was scanned while moving at a speed of 0.2 m/s on a conveyor system. The X-ray source term used in the simulation was obtained by
monoenergetic-electron-beam bombardment onto the target. 4-D simulations were performed for the
moving object. To validate the simulation model, we compared the simulated and measured image
profiles, as well as the pixel counts of the dual-energy detector. The percent differences between
the simulated and measured pixel counts and the image profiles were all within 5%. Thus, we
concluded that our simulation model for the X-ray scanner can be considered to be reliable.
Causal analysis of Canada’s environment-growth nexus for inclusive development metrics
Authors: Iwuoha Sochi , Onochie Joseph I
Published: January 2024

Little is known about the relevance of alternative measures of growth in environmental and developmental economic analyses. In Canada, for example, no literature exists on whether there is a causal link between the level of environmental performance and alternative measures of economic progress (which are argued to better capture the overall economic wellbeing than the gross domestic product—GDP). As environmental policies may relate to overall economic wellbeing, we opine that understanding overall economic progress is essential for achieving sustainable development and emissions reduction targets. This paper addresses a knowledge gap by assessing the causal links and directions between Canada’s national-level greenhouse gas emissions (GHG—as an indicator of environmental performance) and three alternative measures of economic growth, namely, gross national disposable income (GNDI), human development index (HDI), and index of economic freedom (IEF); from 1995 to 2019. Our results indicate that causality exists between Canada’s GHG and the alternative growth measures. This implies that Canada’s GNDI, HDI, and IEF may be useful and complementary to GDP in forecasting the national-level total GHG emissions. The research provides insights to further consider the role of overall economic wellbeing in the quest for sustainable, lower-emissions, economic development in Canada and by extension in other nations.
Multilayer nanodrug delivery system with spatiotemporal drug release improves tumor microenvironment for synergistic anticancer therapy
Authors: Cai Jiahui , Yang Yibo , Zhang Jia , Bai Zhimin , Zhang Xin , Li Kun , Shi Ming , Liu Zhiwei , Gao Liming , Wang Jidong , Li Jian
Published: January 2024

The inflammatory response is one of the general symptoms that accompany tumorigenesis, the pro-inflammatory factors cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandin-2 (PGE-2) in the inflammatory environment surrounding tumors possess promoting tumor development, metastasis and angiogenesis effects. In addition, the hypoxic environment of tumors severely limits the effectiveness of photodynamic therapy (PDT). In this study, a universal extracellular-intracellular ‘on-demand’ release nanomedicine DOX@PDA-ICG@MnO2@GN-CEL was developed for the combined fight against malignant tumors using a spatiotemporal controlled gelatin coated polydopamine (PDA@GN) as the carrier and loaded with the chemotherapeutic drug doxorubicin (DOX), the photosensitizer indocyanine green (ICG), the PDT enhancer MnO2 and the anti-inflammatory drug celecoxib (CEL) individually. Our results showed that DOX@PDA-ICG@MnO2@GN-CEL could release CEL extracellularly by matrix metalloproteinase-2 response and inhibit the COX-2/PGE-2 pathway, reduce chemotherapy resistance and attenuate the concurrent inflammation. After entering the tumor cells, the remaining DOX@PDA-ICG@MnO2 released DOX, ICG and MnO2 intracellularly through PDA acid response. MnO2 promoted the degradation of endogenous H2O2 to generate oxygen under acidic conditions to alleviate the tumor hypoxic environment, enhance PDT triggered by ICG. PDA and ICG exhibited photothermal therapy synergistically, and DOX exerted chemotherapy with reduced chemotherapy resistance. The dual responsive drug release switch enabled the chemotherapeutic, photothermal, photodynamic and anti-inflammatory drugs precisely acted on different sites of tumor tissues and realized a promising multimodal combination therapy.
Current advances in engineering meniscal tissues: insights into 3D printing, injectable hydrogels and physical stimulation based strategies
Authors: Bandyopadhyay Ashutosh , Ghibhela Baishali , Mandal Biman B
Published: January 2024

The knee meniscus is the cushioning fibro-cartilage tissue present in between the femoral condyles and tibial plateau of the knee joint. It is largely avascular in nature and suffers from a wide range of tears and injuries caused by accidents, trauma, active lifestyle of the populace and old age of individuals. Healing of the meniscus is especially difficult due to its avascularity and hence requires invasive arthroscopic approaches such as surgical resection, suturing or implantation. Though various tissue engineering approaches are proposed for the treatment of meniscus tears, three-dimensional (3D) printing/bioprinting, injectable hydrogels and physical stimulation involving modalities are gaining forefront in the past decade. A plethora of new printing approaches such as direct light photopolymerization and volumetric printing, injectable biomaterials loaded with growth factors and physical stimulation such as low-intensity ultrasound approaches are being added to the treatment portfolio along with the contemporary tear mitigation measures. This review discusses on the necessary design considerations, approaches for 3D modeling and design practices for meniscal tear treatments within the scope of tissue engineering and regeneration. Also, the suitable materials, cell sources, growth factors, fixation and lubrication strategies, mechanical stimulation approaches, 3D printing strategies and injectable hydrogels for meniscal tear management have been elaborated. We have also summarized potential technologies and the potential framework that could be the herald of the future of meniscus tissue engineering and repair approaches.
Directing ligament-mimetic bi-directional cell organization in scaffolds through zone-specific microarchitecture for ligament tissue engineering
Authors: Sriram M , Priya Smriti , Mahajan Aman , Katti Dhirendra S
Published: January 2024

Ligament tissues exhibit zone-specific anisotropic cell organization. The cells in ligament-proper are longitudinally oriented, whereas, the cells in epiligament are circumferentially oriented. Therefore, scaffolds developed to regenerate ligament tissues should possess adequate architectural features to govern ligament-mimetic bi-directional cell organization. The scaffold architectural features along with ligament-mimetic cell organization may ultimately yield neo-tissues with ligament-like extracellular matrix (ECM) structure and biomechanical properties. Towards this goal, we fabricated a silk/gelatin-based core–shell scaffold (csSG) with zone-specific anisotropic architectural features, wherein, the core of the scaffold possessed longitudinally aligned pores while the shell of the scaffold possessed parallel microgrooves that are aligned circumferentially around the surface of the scaffold. The ligament-mimetic architectural features significantly improved the mechanical properties of the scaffold. Moreover, architectural features of the csSG scaffold governed zone-specific anisotropic organization of cells. The cells in the core were longitudinally oriented as observed in the ligament-proper and the cells on the shell were circumferentially oriented as observed in epiligament. This bi-directional cell orientation partially mimicked the complex cellular network in native ligament tissue. Additionally, both the core and the shell individually supported fibrogenic differentiation of stem cells which further improved their potential for ligament tissue engineering. Further, the aligned pores of the core could govern unidirectional organization of ECM deposited by cells which is crucial for regenerating anisotropic tissues like ligaments. Finally, when implanted subcutaneously in mice, the scaffolds retained their anisotropic architecture for at least 2 weeks, were biocompatible, supported cell infiltration and governed anisotropic organization of cells and ECM. Taken together, the fabricated biomimetic csSG scaffold, through its zone-specific architectural features, could govern ligament-mimetic cellular and ECM organization which is ultimately expected to achieve regeneration of ligament tissues with native-like hierarchical structure and biomechanical properties. Consequently, this study introduces bi-directional structural parameters as design criteria for developing scaffolds for ligament tissue engineering.
Hidden in plain sight: hyperspectral documentation of complex biofluorescence produced by the green sea urchin (Strongylocentrotus droebachiensis)
Authors: Juhasz-Dora Thomas , James Philip , Evensen Tor , Lindberg Stein-Kato
Published: January 2024

Biofluorescence in echinoderms is largely unexplored, and even though the green sea urchin Strongylocentrotus droebachiensis is a well-studied species, the presence and/or function of fluorescence remains very poorly understood. Hyperspectral imaging was conducted on adult sea urchins (N = 380) while fluorospectrometric analysis was conducted on sea urchin coelomic fluid (N = 30). Fluorescence was documented in both the spines and coelomic fluid of S. droebachiensis. Intact spines exhibited a low intensity green emission (∼550–600 nm), while broken spines averaged a high emission peak in the green spectrum (∼580 nm). Sea urchins produce a red exudate with a pronounced emission peak (∼680 nm) with a shoulder peak (∼730 nm). The sampled coelomic fluid exhibited high variability, with a majority exhibiting a low-level green fluorescence while pronounced emission peaks (N = 5) were found in the red spectrum (∼680 nm). The complex fluorescence produced by S. droebachiensis warrants further investigation on its applicability for monitoring welfare of sea urchins in aquaculture facilities.
Thermomechanical response of liquid crystal elastomers: role of crosslinker density
Authors: Derets N , Domenici V , Rešetič A , Zalar B
Published: January 2024

In this work thermomechanical properties of main-chain liquid crystal elastomers (MC-LCEs) with different degrees of crosslinking were investigated, and gradual loss of thermomechanical response was observed on repetitive measurements. Specifically, six samples of MC-LCEs were prepared, with crosslinker-to-mesogen relative concentration ranging from 5% to 10% in steps of 1%. The obtained results were then compared to thermomechanical response of side-chain liquid crystal elastomers (SC-LCEs). Additionally, thermomechanical response of polymer dispersed main-chain liquid crystal elastomers (MC-PDLCEs) was investigated. Results indicate that in MC-LCEs the concentration of crosslinker defines thermomechanical response and affects stability of the system. The loss of thermomechanical response is negligible in the case of crosslinker to mesogen ratio being the smallest, namely in 5% sample, and it is unaffected by glasslike to nematic phase transition. SC-LCEs do not show any sign of such behaviour and remain stable after several cycles of thermomechanical measurements.
A combined musculoskeletal and finite element model of a foot to predict plantar pressure distribution
Authors: Kamal Zeinab , Hekman Edsko E G , Verkerke Gijsbertus J
Published: January 2024

In this study, a combined subject-specific numerical and experimental investigation was conducted to explore the plantar pressure of an individual. The research utilized finite element (FE) and musculoskeletal modelling based on computed tomography (CT) images of an ankle-foot complex and three-dimensional gait measurements. Muscle forces were estimated using an individualized multi-body musculoskeletal model in five gait phases. The results of the FE model and gait measurements for the same subject revealed the highest stress concentration of 0.48 MPa in the forefoot, which aligns with previously-reported clinical observations. Additionally, the study found that the encapsulated soft tissue FE model with hyper-elastic properties exhibited higher stresses compared to the model with linear-elastic properties, with maximum ratios of 1.16 and 1.88 MPa in the contact pressure and von-Mises stress, respectively. Furthermore, the numerical simulation demonstrated that the use of an individualized insole caused a reduction of 8.3% in the maximum contact plantar pressure and 14.7% in the maximum von-Mises stress in the encapsulated soft tissue. Overall, the developed model in this investigation holds potential for facilitating further studies on foot pathologies and the improvement of rehabilitation techniques in clinical settings.
Optimal control of large quantum systems: assessing memory and runtime performance of GRAPE
Authors: Lu Yunwei , Joshi Sandeep , San Dinh Vinh , Koch Jens
Published: January 2024

Gradient Ascent Pulse Engineering (GRAPE) is a popular technique in quantum optimal control, and can be combined with automatic differentiation (AD) to facilitate on-the-fly evaluation of cost-function gradients. We illustrate that the convenience of AD comes at a significant memory cost due to the cumulative storage of a large number of states and propagators. For quantum systems of increasing Hilbert space size, this imposes a significant bottleneck. We revisit the strategy of hard-coding gradients in a scheme that fully avoids propagator storage and significantly reduces memory requirements. Separately, we present improvements to numerical state propagation to enhance runtime performance. We benchmark runtime and memory usage and compare this approach to AD-based implementations, with a focus on pushing towards larger Hilbert space sizes. The results confirm that the AD-free approach facilitates the application of optimal control for large quantum systems which would otherwise be difficult to tackle.
A novel hybrid multi-criteria optimization of 3D printing process using grey relational analysis (GRA) coupled with principal component analysis (PCA)
Authors: Ranjan Rajeev , Saha Abhijit
Published: January 2024

Fused deposition modeling (FDM) is renowned as a prominent approach in the realm of 3D printing, where objects are built layer by layer using a heated nozzle to extrude melted materials. This research was conducted to identify the most effective FDM process variables to enhance tensile strength while simultaneously reducing surface roughness. Polylactic Acid (PLA) was chosen to fabricate test samples, showcasing the applications of 3D printing. In the course of this research, we conducted a series of 27 experiments to investigate the fundamental relationship between the parameters and the corresponding responses. The central aim of this study lies in optimizing the input variables viz. printing speed, layer thickness, and carbon deposition (C-deposition) for the technological manufacturing process of embossing parts in the context of Industry 4.0. To enhance both tensile strength and surface roughness simultaneously, a new hybrid method has been suggested. This approach integrates grey relational analysis (GRA) with principal component analysis (PCA) to determine the optimal combination of process parameters in the 3D printing process. Notably, the experiment trial exhibited the highest grey relational grade (GRG), indicating optimal process parameter settings at a printing speed of 100 mm s−1, layer thickness of 0.1 mm, and C-deposition of 15 mg respectively. Additionally, mathematical models are created through response surface methodology to explore the impact of FDM parameters on the grey relational grade. The findings from this study can be utilized in various industries and applications where FDM 3D printing is employed.
Climate impacts of digital use supply chains
Authors: Shi Lin , Brandt Adam , Iancu Dan , Mach Katharine J , Field Chris , Cho Mu-Jung , Ng Michelle , Chey Kyung Jin (Sarah) , Ram Nilam , Robinson Thomas , Reeves Byron
Published: January 2024

Information and communications technology (ICT) has become an indispensable part of our lives. Prior research on climate impact of ICT devices and services mostly makes use of life cycle assessment and energy modeling frameworks focused on embodied greenhouse gas (GHG) emissions. Because these perspectives emphasize the GHGs emissions associated with the construction and distribution of digital devices along production supply chains, not much is known about the GHGs emissions monitored or facilitated by digital device use. In this study, we propose the concept of digital use supply chains (DUSCs) as an orthogonal dimension of digital devices’ life cycle. DUSC refers to the production activities and resource consumption recorded by digital devices. We propose a framework to conceptualize and quantify digital behavior-related GHGs emissions through use of the Screenomics paradigm, where users’ digital screen data are unobtrusively collected moment-by-moment. Through Screenomics’ granular recording of users’ digital behavior, we evaluate behavior-based GHGs emissions traced by the digital devices. DUSC connects individual’s digital behaviors to their global climate change impact, contributing to a more nuanced and complete evaluation of the climate impacts of the digital economy. Our single-case study indicates the estimated scale of the GHGs emissions linked to a user’s one-day digital activities could be three orders of magnitude (1000 times) higher than the emissions associated with the device life cycle alone. DUSC could enable climate change mitigation at a meaningful, actionable level through personalized educational or behavior change programs, and also facilitate novel data-driven feedback loops that may provide digital device users with insights into their personal climate impacts. Recognition and future study of DUSC could accelerate the quantification and standardization of a ‘carbon handprint’ of digital devices and create positive climate impacts from digital products and services.
Social media engagement in health and climate change: an exploratory analysis of Twitter
Authors: Golder Su , Graham Hilary
Published: January 2024

Social media are increasingly used by the public to share information and opinions. This study explores social media engagement in health and climate change through an analysis of English-language posts on Twitter, one of the most widely-used platforms. We searched Twitter from 21 March 2023 to 11 May 2023 for posts related to climate change using climate-related textwords and hashtags; we then used health keywords (‘health’, ‘wellbeing’, ‘illness’, ‘illnesses’, ‘disease’, ‘death’) to identify posts related to health. Focusing on posts from general public users, we investigated the proportion of climate change posts referring to health and, for a random sample of these tweets, undertook a content analysis to identify the ways in which climate change and health were represented. The content analysis drew on media research on ‘framing’, a selective process through which particular aspects of an issue—for example, its causes, impacts and solutions—are highlighted. 668 810 posts related to climate change were posted during the study period. Health-related text words were included in 2.3% (15 434) of these posts. The content analysis pointed to two divergent frames. The first frame represents climate change as real, with real effects on people’s health. The second frame portrays climate change as a hoax, with hoax-generated health effects. While the ‘reality’ frame does not engage with the hoax frame, the latter provides an insistent counter-narrative that questions trust in mainstream science and government policy. Neither frame engages with people’s experiences of health and climate change. In conclusion, our study points to low levels of engagement in health in a key forum for public discussions about climate change. It also asks whether the failure of the ‘reality’ frame to engage either with people’s lived experiences or with hoax framings may be contributing to a polarised debate about climate change and health and hindering consensus-building.
Optimization of national grain imports to balance risk and return: a portfolio theory approach
Authors: Karakoc Deniz Berfin , Konar Megan
Published: January 2024

Global grain trade plays a key role in food security. Many nations rely on imported grain to meet their dietary requirements. Grain imports may be at risk due to weather shocks, economic crises, or international conflicts. Countries aim to balance import risk with the expected return of their grain supplies. This research brings these dual objectives together in an innovative modern portfolio theory framework. Modern portfolio theory provides a set of concepts to formulate the trade-off between risk and expected return in national grain imports. Using Markowitz’s mean-variance optimization model, we identify opportunities to reduce risk in existing national grain import accounts, without increasing costs under realistic supply mass constraints of trade partners. Several major grain importers may be able to reduce risk in their grain imports without increasing cost, such as wheat imports in Egypt, maize imports in Vietnam, and rice imports in Saudi Arabia. However, some countries would indeed have to pay more to achieve more stable grain supplies, such as wheat imports in Turkey. This study provides a framework to quantify the different costs, benefits, and levels of risk in grain trade that can inform future research and decision-making.
On extra zeros of 𝑝-adic Rankin–Selberg 𝐿-functions
Authors: Benois D. , Horte S.
Published: January 2024

A version of the extra-zero conjecture, formulated by the first named author, is proved for

p
p

-adic

L
L

-functions associated with Rankin–Selberg convolutions of modular forms of the same weight. This result provides an evidence in support of this conjecture in the noncritical case, which remained essentially unstudied.
Triangulated categories of framed bispectra and framed motives
Authors: Garkusha G. , Panin I.
Published: January 2024

An alternative approach to the classical Morel–Voevodsky stable motivic homotopy theory

S
H
(
k
)

SH(k)

is suggested. The triangulated category of framed bispectra

S

H

nis

fr

(
k
)

SH_{\operatorname {nis}}^{\operatorname {fr}}(k)

and effective framed bispectra

S

H

nis

fr
,
eff

(
k
)

SH_{\operatorname {nis}}^{\operatorname {fr},\operatorname {eff}}(k)

are introduced in the paper. Both triangulated categories only involve Nisnevich local equivalences and have nothing to do with any kind of motivic equivalences. It is shown that

S

H

nis

fr

(
k
)

SH_{\operatorname {nis}}^{\operatorname {fr}}(k)

and

S

H

nis

fr
,
eff

(
k
)

SH_{\operatorname {nis}}^{\operatorname {fr},\operatorname {eff}}(k)

recover classical Morel–Voevodsky triangulated categories of bispectra

S
H
(
k
)

SH(k)

and effective bispectra

S

H

eff

(
k
)

SH^{\operatorname {eff}}(k)

respectively.

Also,

S
H
(
k
)

SH(k)

and

S

H

eff

(
k
)

SH^{\operatorname {eff}}(k)

are recovered as the triangulated category of framed motivic spectral functors

S

H

S
1

fr

[

F

r
0

(
k
)
]

SH_{S^1}^{\operatorname {fr}}[\mathcal {F}r_0(k)]

and the triangulated category of framed motives

S
H

fr

(
k
)

\mathcal {SH}^{\operatorname {fr}}(k)

constructed in the paper.
Geometry of symmetric spaces of type EIII
Authors: Petrov V. , Semenov A.
Published: January 2024

Atsuyama’s result on the geometry of symmetric spaces of type EIII is generalized to the case of arbitrary fields of characteristic not 2 or 3. As an application, a variant of the “chain lemma” for microweight tori in groups of type

E
6

E_6

is proved.
Habitat Loss
Authors: Pons-Hernández Mònica
Published: January 2024

Habitat loss refers to the disappearance of natural environments that house specific plant and animal species. Habitat loss encompass three main types: habitat destruction, degradation, and fragmentation. Habitat destruction involves extensive devastation of natural environments, habitat degradation results from the depletion of vital resources like water and food, and habitat fragmentation refers to the conversion of large wild areas into smaller ones. All forms of habitat loss are endangering species’ survival. Primarily driven by human activities, the loss of habitat adversely affects terrestrial and aquatic ecosystems. Land conversion for agriculture, mining, and urban development leads to the loss of forests and other habitats. Aquatic environments also suffer habitat loss caused by dredging, pollution, or waste. Moreover, climate change, a consequence of global warming, further intensifies habitat loss. Droughts, floods, wildfires, and changing water conditions impact both terrestrial and aquatic habitats.

Although the link between habitat destruction and criminology may not be immediately apparent, its harmful effects make it of interest to criminologists. Green criminology’s focus on harms, along with crimes and the impacts of these harms toward all species and environments, makes habitat loss of key interest for criminology. Habitat loss falls under the scope of green criminology because of its effects on ecosystems, humans, and nonhuman species. It is important to note that habitat and biodiversity loss are deeply intertwined. The case of the European eel illustrates the (slow) violence linked to habitat loss and its effects on biodiversity. European eels face multiple threats due to habitat destruction, fragmentation, and degradation. The construction of weirs and dams is one of the major factors that negatively impacts eels. It restricts their movement and blocks both upstream and downstream migration routes, destroying and fragmenting their habitat. As a migratory species, freedom of movement is crucial for their survival, making the presence of these barriers a significant concern. Additionally, global warming and ocean modifications further degrade eels’ habitats, affecting the survival of larvae during their drift and silver (adult) eels during their spawning migration. Furthermore, the introduction of nonnative species and the increasing contamination levels in eel habitats also contribute to their degradation, posing another danger to the species’ survival. Overall, European eels are a landmark opportunity to highlight the diverse range of causes of habitat loss and the (slow) violence ingrained in it.
Aminu Kano
Authors: Salau Mohammed Bashir , Oluokun Oyedele
Published: January 2024

Aminu Kano was born into the family of Mallam Yusufu and Malama Rakaiya of the Sudawa quarters of Kano city in 1920. He obtained Islamic education and attended various local Western schools before serving as a teacher at the Bauchi Provincial Middle School. After leaving Bauchi, he attended the University of London, where he became more politically active. Upon returning to Nigeria from London, Kano served in different capacities, but mainly as a politician, a statesman-parliamentarian, and a cabinet minister. In the context of serving in these capacities, he was primarily committed to attacking the corruption and oppression of the emirate system, fighting for the liberation of women, fighting for Nigeria’s independence, promoting the democratization of Northern Nigeria, and fighting for Nigeria’s unity. By 1980, Kano’s focus on such issues had led to some important victories including the weakening of the emirate system. By this same date, Kano had had many wives even though he never embraced polygamy. In 1983, Kano died of a stroke. However, his ideas and work still have an impact on 21st-century Nigeria. The primary materials for the study of his ideas, work, and legacy include those Kano himself wrote, those written by other individuals, and oral data. Some of the extant literature based partly on such materials have primarily provided biographical details on Kano, while others have considered either his social and political thoughts or his legacy. Despite this, there are still significant gaps that exist in the relevant literature, which provides future research opportunities.
Slavery and Resistance in West Central Africa
Authors: Salas Esteban
Published: January 2024

The institution of slavery in West Central Africa predated the arrival of Europeans in the late 15th century, though there is limited information about its nature and extent or the gender and age dynamics prior to that period. Slavery in different West Central African societies in the 16th and 17th centuries was broadly defined as the legal and social outsider status of people originating from different states or chiefdoms and brought under captivity as a result of raids or wars, the payment for taxes from tributary states and chiefdoms, punishment for crimes such as adultery in royal circles, or direct purchase. This has been identified as lineage slavery and was distinct from the Atlantic slave trade.

Yet, the characteristics of slavery changed throughout the centuries. In the 16th and 17th centuries, local captives could become part of the kin of their owners after a process of integration in their new host society. They turned into insiders, even in instances in which they retained their enslaved status. However, from the 17th century, the expansion of the Atlantic slave trade and Portuguese colonialism resulted in a growing demand for captives, transforming the relations between captives and enslavers. The increasing presence of enslavers and their demand for different supplies, such as foodstuffs, resulted in a greater demand for labor in Portuguese colonial settlements, vassal chiefdoms, and autonomous states. Violence increased and individual kidnapping became the main method of enslavement, though warfare persisted as a method of capture well into the mid-19th century. Relations of dependency were increasingly disrupted and local captives became more vulnerable to deportation to other areas of West Central Africa and different parts of the world. Furthermore, the risk for insiders to be enslaved, re-enslaved, or deported increased, contributing to the redefinition of the meaning of slavery. Finally, following the prohibition of slavery by Portuguese colonial law in 1876, other forms of forced labor resembling slavery in varied ways emerged and were practiced until the third quarter of the 20th century. Resistance persisted throughout.
Experimentation in Physics in the 20th and 21st Centuries
Authors: Franklin Allan , Laymon Ronald
Published: January 2024

What is the general notion of pursuit that correlates to scientific experiments in physics? What are the roles of experiments in physics, the epistemology of experiments, arguments around credibility, and experimental investigations in the 20th and 21st centuries? The experimental enterprise is a complex and interdependent activity wherein experiments yield results where those results form the basis for answers to questions posed by the many uses of the experiment. It is worth examining the significance of exploratory experiments and testing theories, as experimenters often apply several strategies in arguing for the correctness of their results.
Circuit Model of Quantum Computation
Authors: Wootton James
Published: January 2024

Quantum circuits are an abstract framework to represent quantum dynamics. They are used to formally describe and reason about processes within quantum information technology. They are primarily used in quantum computation, quantum communication, and quantum cryptography—for which they provide a machine code–level description of quantum algorithms and protocols. The quantum circuit model is an abstract representation of these technologies based on the use of quantum circuits, with which algorithms and protocols can be concretely developed and studied.

Quantum circuits are typically based on the concept of qubits: two-level quantum systems that serve as a fundamental unit of quantum hardware. In their simplest form, circuits take a set of qubits initialized in a simple known state, apply a set of discrete single- and two-qubit evolutions known as “gates,” and then finally measure all qubits. Any quantum computation can be expressed in this form through a suitable choice of gates, in a quantum analogy of the Boolean circuit model of conventional digital computation.

More complex versions of quantum circuits can include features such as qudits, which are higher level quantum systems, as well as the ability to reset and measure qubits or qudits throughout the circuit. However, even the simplest form of the model can be used to emulate such behavior, making it fully sufficient to describe quantum information technology. It is possible to use the quantum circuit model to emulate other models of quantum computing, such as the adiabatic and measurement-based models, which formalize quantum algorithms in a very different way.

As well as being a theoretical model to reason about quantum information technology, quantum circuits can also provide a blueprint for quantum hardware development. Corresponding hardware is based on the concept of building physical systems that can be controlled in the way required for qubits or qudits, including applying gates on them in sequence and performing measurements.