bluuebunny/crossref_metadata_2025 huggingface dataset:
Deterioration of Cement-Based Materials in Low-Temperature Seawater
Authors: Kobayashi Mari , Takahashi Keisuke , Kawabata Yuichiro
Published: July 2023

Cementitious materials have potential for infrastructure development in low-temperature marine environments, including in seawater at high latitudes and in deep-sea environments (water depths of >1000 m). Although the marine deterioration of cementitious materials has been widely investigated, the influence of seawater temperature has not been elucidated. In this study, to determine the effects of low-temperature seawater on the durability of cementitious materials, cement paste specimens were immersed in a seawater tank at room temperature and 2 °C for 433 days. The specimen immersed in low-temperature seawater exhibited significant deterioration with a partially collapsed surface, whereas the specimen immersed in room-temperature seawater maintained its original shape. Following low-temperature immersion, Ca dissolution was more pronounced and dissolved portlandite, decalcified calcium (alumino)silicate hydrate (C–(A-)S–H), magnesium (alumino)silicate hydrate (M–(A-)S–H), and thaumasite were observed on the collapsed surface. Such significant deterioration can be attributed to the increased solubility of portlandite under low-temperature conditions, which could promote Ca dissolution and subsequently lead to C–(A-)S–H decalcification and the formation of M–(A-)S–H and thaumasite. These insights are expected to contribute to the successful construction and maintenance of cementitious structures in low-temperature seawater.
Analysis of Factors Influencing the Modulus of Hot-Recycled Asphalt Mixture with High RAP
Authors: Chen Zining , Liu Boying , Feng Decheng , Li Gang
Published: July 2023

Generally, the dynamic modulus and bending stiffness modulus are used to evaluate the mechanical properties of asphalt mixture, and they are also used as basic parameters for asphalt mixture design. Therefore, a study was conducted on changes in the dynamic modulus and bending stiffness modulus of hot-recycled asphalt mixture with high levels of reclaimed asphalt pavement (RAP) under the influence of different factors: dosage of regenerant, curing temperature, and curing time. The performance of reclaimed asphalt pavement (RAP) was first evaluated. Then, the hot-recycled asphalt mixture was adjusted and designed in order to conduct modulus experiments, composed of the dynamic modulus test and three-point bending test. Finally, the influencing factors were not only qualitatively but also quantitatively analyzed to clarify the change laws of the mechanical parameters of hot-recycled asphalt mixture. The results showed that the modulus of the recycled asphalt mixture first decreased, then increased, and then decreased with increasing dosage of regenerant. As the curing time or temperature increased, the modulus first decreased and then increased. In terms of the dynamic modulus of the hot-recycled asphalt mixture, the curing time had the greatest impact, followed by dosage of the regenerant and curing temperature. For bending stiffness modulus, the influence of dosage of the regenerant was the greatest, followed by curing time and curing temperature. For the bending stiffness modulus of hot-recycled asphalt mixture, the curing conditions had a greater influence compared with the dynamic modulus.
Modelling the Kerf Angle, Roughness and Waviness of the Surface of Inconel 718 in an Abrasive Water Jet Cutting Process
Authors: Płodzień Marcin , Żyłka Łukasz , Żak Krzysztof , Wojciechowski Szymon
Published: July 2023

An experimental study of the abrasive water jet cutting process of Inconel 718 alloy samples with varying values of cutting speed, abrasive flow rate and cutting material height was carried out. Surface roughness and waviness were measured at different cutting depths, and the variation of the kerf angle was studied. It was shown that the depth of cut has the greatest effect on roughness and waviness. The height of the sample has no impact on the roughness and waviness at a particular depth of cut. As the depth of cut increases, in most cases, roughness and waviness increase as well. It has been proven that the cutting speed has a negligible effect on surface roughness, but it has a significant effect on surface waviness. The waviness, on the other hand, depends only slightly on the abrasive flow. It has been proven that the kerf angle does not depend on the abrasive flow. The kerf angle depends mainly on the height of the sample. The models were developed for the parameters of roughness Ra and Rz, waviness Wa and Wz and kerf angle. All models were calculated without separating the surface into smooth and rough cutting regions.
A Study on Long-Term Oxidation and Thermal Shock Performance of Nanostructured YSZ/NiCrAlY TBC with a Less Dense Bond Coat
Authors: Badea Teodor-Adrian , Condruz Mihaela-Raluca , Paraschiv Alexandru
Published: July 2023

This paper focused on studying the performance of a nanostructured thermal barrier coating (TBC) system deposited by APS, which had a bond coat with inter-lamellar porosities that resulted during the manufacturing process. The higher porosity level of the bond coat was studied as a possible way to keep the thickness of the TGO under control, as it is distributed on a higher surface, thereby reducing the chance of top-coat (TC) spallation during long-term oxidation and high-temperature thermal shock. The TBC system consisted of nanostructured yttria partially stabilized zirconia (YSZ) as a top coat and a conventional NiCrAlY bond coat. Inter-lamellar porosities ensured the development of a TGO distributed on a higher surface without affecting the overall coating performance. Based on long-term isothermal oxidation tests performed at 1150 °C, the inter-lamellar pores do not affect the high resistance of nanostructured TBCs in case of long-term iso-thermal oxidation at 1150 °C. The ceramic layer withstands the high-temperature exposure for 800 h of maintaining without showing major exfoliation. Fine cracks were discovered in the ceramic coating after 400 h of isothermal oxidation, and larger cracks were found after 800 h of exposure. An increase in both ceramic and bond-coat compaction was observed after prolonged high-temperature exposure, and this was sustained by the higher adhesion strength. Moreover, in extreme conditions, under high-temperature thermal shock cycles, the TBC withstands for 1242 cycles at 1200 °C and 555 cycles at 1250 °C.
Time-Lapse Observation of Crevice Corrosion in Grade 2205 Duplex Stainless Steel
Authors: Aoki So , Engelberg Dirk L.
Published: July 2023

The objective of this study was to investigate and visualize the initiation and propagation of crevice corrosion in grade 2205 duplex stainless steel by means of time-lapse imaging. Transparent Poly-Methyl-Meth-Acrylate washer and disk were coupled with duplex stainless steel to create an artificial crevice, with electrochemical monitoring applied to obtain information about the nucleation and propagation characteristics. All nucleation sites and corroding areas inside crevices were recorded in situ using a digital microscope set-up. Localized corrosion initiated close to the edge of the washer, where the crevice gap was very tight, with active corrosion sites then propagating underneath the disk into areas with wider gaps, towards the crevice mouth. The growth was associated with a rise in anodic current interlaced with sudden current drops, with parallel hydrogen gas evolution also observed within the crevice. The current drops were associated with a sudden change in growth direction, and once corrosion reached the crevice mouth, the propagation continued circumferentially and in depth. This allowed different corrosion regions to develop, showing selective dissolution of austenite, a region with dissolution of both phases, followed by a region where only ferrite dissolved. The effect of applied electrochemical potential, combined with time-lapse imaging, provides a powerful tool for in situ corrosion studies.
Auxetic Behaviour of Rigid Connected Squares
Authors: Plewa Julian , Płońska Małgorzata , Junak Grzegorz
Published: July 2023

The paper presents an analysis of rotating rigid unit (RRU) auxetic structures, the special property of which is negative Poisson’s ratio. The crucial features of such modified structures are the well-functioning linkages of the square units at their pivot points. This ensures the stable functioning of such structures in tension or compression. The presented geometrical analysis of these auxetic structures may facilitate their adequate construction and allow one to determine the expected values of their expansion as well as the desired porosity. The results are confirmed based on the behaviour of physical models produced by the assembly of square units. The change in the dimensions of the physical models when moving from a closed to an open position is consistent with the predictions of the geometric models. By modifying the well-known ‘rotating squares’ model, physical structures with auxetic properties are obtained that can be utilised in industrial conditions, where a simultaneous change of linear dimensions is needed—either in compression or in tension. The assembly method may prove efficient in building such structures, given the abilities of assembly robots to regularly arrange the unit cells in lines and rows and to connect them with rings at the designated positions (evenly spaced perforations). The presented auxetic structures might find their potential application in, e.g., expansion joints or structures in which the porosity is mechanically changed, such as mesoscale structures. The tested structures subjected to high compressive forces buckle when the yield strength of the rigid unit material is exceeded.
Particleboard Creation from Agricultural Waste Residue of Seed Hemp
Authors: Zvirgzds Kristaps , Kirilovs Edgars , Kukle Silvija , Zotova Inga , Gudro Ilze , Gross Uldis
Published: July 2023

In this research, agricultural residue of seed hemp variety “Adzelvieši” was used to create hemp particleboard samples. Hemp was grown in three experimental fields where it was observed that after seed harvesting, 3.5 tonnes of hemp stems per hectare remained. The plants were processed with milling, cutting, and sieving equipment. Moisture content and particle size distribution were observed throughout raw material processing. Hemp boards were produced using the cold pressing method with 10% urea formaldehyde resin as the binder. The boards were made as 20 mm thick single-layer parts with a density range of 220 ± 30 kg/m3 and porosity of 86%. Board structural analysis was performed using optical microscopy and scanning electron microscopy methods. Mechanical strength was determined by performing bending strength, internal bond strength, and screw withdrawal tests. The thermal conductivity reached 0.047 ± 0.008 W/(mK). The results were compared with industrially produced hemp shive boards and materials in the developmental or production stage. The feasibility for the experimental production cycle proposed in the study is discussed.
The Effect of SMA Fiber Content on the Bending and Self-Recovery Performance of ECC Beams
Authors: Yang Zhao , Ren Yun , Wu Qing
Published: July 2023

The addition of superelastic shape memory alloy fibers (SMAF) into engineering cementitious composites (ECC) can create a new type of SMAF-ECC composite material with good self-recovery and energy dissipation performance, which is very suitable for seismic structures. In this study, 10 groups of beam specimens with different volume contents of SMAF were fabricated, and the bending performance, deflection recovery and energy dissipation ability of these beams were studied through three-point bending cyclic loading tests. The failure mode, peak load, load–deflection curve, crack width and other indicators of the specimens were analyzed, and the relationship expression between fiber content and bending strength was established by fitting analysis. The results show that adding SMA fibers can significantly improve the peak load of ECC beams, with a maximum increase of 48.31%. The knotted SMA fibers can fully exert their superelasticity, providing the beam specimens with crack self-closing and deflection recovery ability. When the volume content of SMA fibers is 0–0.6%, the bending strength, energy dissipation ability and deflection recovery ability of the composite material beams increase with the increase in fiber content. When the volume content of SMA fibers is 0.6–1.0%, the above indicators decrease with the increase in fiber content. The suggested equations can well reflect the relationship between fiber content and beam bending strength. The research results of this paper provide theoretical support for the engineering application of SMAF-ECC composite materials.
Assessment of a Fully Renewable System for the Total Decarbonization of the Economy with Full Demand Coverage on Islands Connected to a Central Grid: The Balearic Case in 2040
Authors: Rivera Yago , Blanco David , Bastida-Molina Paula , Berna-Escriche César
Published: July 2023

The transition to clean electricity generation is a crucial focus for achieving the current objectives of economy decarbonization. The Balearic Archipelago faces significant environmental, economic, and social challenges in shifting from a predominantly fossil fuel-based economy to one based on renewable sources. This study proposes implementing a renewable energy mix and decarbonizing the economy of the Balearic Islands by 2040. The proposed system involves an entirely renewable generation system with interconnections between the four Balearic islands and the Spanish mainland grid via a 650 MW submarine cable. This flexible electrical exchange can cover approximately 35% of the peak demand of 1900 MW. The scenario comprises a 6 GWp solar photovoltaic system, a wind system of under 1.2 GWp, and a 600 MW biomass system as generation sub-systems. A vanadium redox flow battery sub-system with a storage capacity of approximately 21 GWh and 2.5 GWp power is available to ensure system manageability. This system’s levelized electricity cost (LCOE) is around 13.75 cEUR/kWh. The design also incorporates hydrogen as an alternative for difficult-to-electrify uses, achieving effective decarbonization of all final energy uses. A production of slightly over 5 × 104 tH2 per year is required, with 1.7 GW of electrolyzer power using excess electricity and water resources. The system enables a significant level of economy decarbonization, although it requires substantial investments in both generation sources and storage.
Low Cost Evolutionary Neural Architecture Search (LENAS) Applied to Traffic Forecasting
Authors: Klosa Daniel , Büskens Christof
Published: July 2023

Traffic forecasting is an important task for transportation engineering as it helps authorities to plan and control traffic flow, detect congestion, and reduce environmental impact. Deep learning techniques have gained traction in handling such complex datasets, but require expertise in neural architecture engineering, often beyond the scope of traffic management decision-makers. Our study aims to address this challenge by using neural architecture search (NAS) methods. These methods, which simplify neural architecture engineering by discovering task-specific neural architectures, are only recently applied to traffic prediction. We specifically focus on the performance estimation of neural architectures, a computationally demanding sub-problem of NAS, that often hinders the real-world application of these methods. Extending prior work on evolutionary NAS (ENAS), our work evaluates the utility of zero-cost (ZC) proxies, recently emerged cost-effective evaluators of network architectures. These proxies operate without necessitating training, thereby circumventing the computational bottleneck, albeit at a slight cost to accuracy. Our findings indicate that, when integrated into the ENAS framework, ZC proxies can accelerate the search process by two orders of magnitude at a small cost of accuracy. These results establish the viability of ZC proxies as a practical solution to accelerate NAS methods while maintaining model accuracy. Our research contributes to the domain by showcasing how ZC proxies can enhance the accessibility and usability of NAS methods for traffic forecasting, despite potential limitations in neural architecture engineering expertise. This novel approach significantly aids in the efficient application of deep learning techniques in real-world traffic management scenarios.
Image Restoration with Fractional-Order Total Variation Regularization and Group Sparsity
Authors: Bhutto Jameel Ahmed , Khan Asad , Rahman Ziaur
Published: July 2023

In this paper, we present a novel image denoising algorithm, specifically designed to effectively restore both the edges and texture of images. This is achieved through the use of an innovative model known as the overlapping group sparse fractional-order total variation regularization model (OGS-FOTVR). The OGS-FOTVR model ingeniously combines the benefits of the fractional-order (FO) variation domain with an overlapping group sparsity measure, which acts as its regularization component. This is further enhanced by the inclusion of the well-established L2-norm, which serves as the fidelity term. To simplify the model, we employ the alternating direction method of multipliers (ADMM), which breaks down the model into a series of more manageable sub-problems. Each of these sub-problems can then be addressed individually. However, the sub-problem involving the overlapping group sparse FO regularization presents a high level of complexity. To address this, we construct an alternative function for this sub-problem, utilizing the mean inequality principle. Subsequently, we employ the majorize-minimization (MM) algorithm to solve it. Empirical results strongly support the effectiveness of the OGS-FOTVR model, demonstrating its ability to accurately recover texture and edge information in images. Notably, the model performs better than several advanced variational alternatives, as indicated by superior performance metrics across three image datasets, PSNR, and SSIM.
Fuzzy Approximating Metrics, Approximating Parametrized Metrics and Their Relations with Fuzzy Partial Metrics
Authors: Bēts Raivis , Šostak Alexander
Published: July 2023

We generalize the concept of a fuzzy metric by introducing its approximating counterpart in order to make it more appropriate for the study of some problems related to combinatorics on words. We establish close relations between fuzzy approximating metrics in the case of special t-norms and approximating parametrized metrics, discuss some relations between fuzzy approximating metrics and fuzzy partial metrics, as well as showing some possible applications of approximating parametrized metrics in the problems of combinatorics on words.
Evaluation of Convergent, Discriminant, and Criterion Validity of the Cuestionario Burnout Granada-University Students
Authors: Ortega-Campos Elena , Cañadas Gustavo R. , Aguayo-Estremera Raimundo , Ariza Tania , Monsalve-Reyes Carolina S. , Suleiman-Martos Nora , De la Fuente-Solana Emilia I.
Published: July 2023

Burnout is a health problem that affects professionals and students or professionals in training, especially those in health areas. For this reason, it is necessary that it is properly identified to prevent the impact it can have on the work and personal areas of the people who suffer from it. The aim of this work is to study the convergent, discriminant, and criterion validity of the Cuestionario Burnout Granada-University Students. The sample consisted of 463 undergraduate nursing students, selected by non-probabilistic convenience sampling, who participated voluntarily and anonymously in the study. The mean age of the participants was 21.9 (5.12) years, mostly female (74.1%), single (95.8%), and childless (95.6%). Information was collected face-to-face, and the instruments were completed on paper. Comparisons were made in the three dimensions of burnout of the CBG-USS between students with and without burnout, finding statistically significant differences in all three dimensions: Emotional Exhaustion (p < 0.001, d = 0.674), Cynicism (p < 0.001, d = 0.479), and Academic Efficacy (p < 0.001, d = −0.607). The Cuestionario Burnout Granada-University Students presents adequate reliability and validity indices, which demonstrates its usefulness in the identification of burnout. This syndrome has traditionally been measured in professionals, but students also present burnout, so it is necessary to have specific burnout instruments for students, since the pre-work situation and stressors of students are different from those of workers. In order to work on the prevention of university burnout, it is essential to have specific instruments for professionals in training that help in the detection of students with burnout.
Investigating A Multi-Domain Polyketide Synthase in Amphidinium carterae
Authors: Haq Saddef , Oyler Benjamin L. , Williams Ernest , Khan Mohd M. , Goodlett David R. , Bachvaroff Tsvetan , Place Allen R.
Published: July 2023

Dinoflagellates are unicellular organisms that are implicated in harmful algal blooms (HABs) caused by potent toxins that are produced through polyketide synthase (PKS) pathways. However, the exact mechanisms of toxin synthesis are unknown due to a lack of genomic segregation of fat, toxins, and other PKS-based pathways. To better understand the underlying mechanisms, the actions and expression of the PKS proteins were investigated using the toxic dinoflagellate Amphidinium carterae as a model. Cerulenin, a known ketosynthase inhibitor, was shown to reduce acetate incorporation into all fat classes with the toxins amphidinol and sulpho-amphidinol. The mass spectrometry analysis of cerulenin-reacted synthetic peptides derived from ketosynthase domains of A. carterae multimodular PKS transcripts demonstrated a strong covalent bond that could be localized using collision-induced dissociation. One multi-modular PKS sequence present in all dinoflagellates surveyed to date was found to lack an AT domain in toxin-producing species, indicating trans-acting domains, and was shown by Western blotting to be post-transcriptionally processed. These results demonstrate how toxin synthesis in dinoflagellates can be differentiated from fat synthesis despite common underlying pathway.
Is a Washer a Mandatory Component in Young Trauma Patients with S1-S2 Iliosacral Screw Fixation of Posterior Pelvis Ring Injuries? A Biomechanical Study
Authors: Berk Till , Zderic Ivan , Schwarzenberg Peter , Pastor Torsten , Halvachizadeh Sascha , Richards Geoff , Gueorguiev Boyko , Pape Hans-Christoph
Published: July 2023

Background and purpose: Cannulated screws are standard implants for percutaneous fixa-tion of posterior pelvis ring injuries. The choice of whether to use these screws in combination with a washer is still undecided. The aim of this study was to evaluate the biomechanical competence of S1-S2 sacroiliac (SI) screw fixation with and without using a washer across three different screw designs. Material and Methods: Twenty-four composite pelvises were used and an SI joint injury type APC III according to the Young and Burgess classification was simulated. Fixation of the posterior pelvis ring was performed using either partially threaded short screws, fully threaded short screws, or fully threaded long transsacral screws. Biomechanical testing was performed under progressively increasing cyclic loading until failure, with monitoring of the intersegmental and bone-implant movements via motion tracking. Results: The number of cycles to failure and the corresponding load at failure (N) were significantly higher for the fully threaded short screws with a washer (3972 ± 600/398.6 ± 30.0) versus its counterpart without a washer (2993 ± 527/349.7 ± 26.4), p = 0.026. In contrast, these two parameters did not reveal any significant differences when comparing fixations with and without a washer using either partially threaded short of fully threaded long transsacral screws, p ≥ 0.359. Conclusions: From a biomechanical perspective, a washer could be optional when using partially threaded short or fully threaded long transsacral S1-S2 screws for treatment of posterior pelvis ring injuries in young trauma patients. Yet, the omission of the washer in fully threaded short screws could lead to a significant diminished biomechanical stability.
Intramuscular Electrical Stimulation for the Treatment of Trigger Points in Patients with Chronic Migraine: A Protocol for a Pilot Study Using a Single-Case Experimental Design
Authors: Perreault Thomas , Arendt-Nielson Lars , Fernández-de-las-Peñas César , Dommerholt Jan , Herrero Pablo , Hubbard Ryan
Published: July 2023

Background and Objectives: Trigger points (TrPs) are prevalent in patients with migraine headaches. Needling interventions targeting TrPs in migraine patients may reduce the intensity and frequency of headaches, yet systematic reviews reveal a lack of robust evidence. Intramuscular electrical stimulation (IMES) is a modality that delivers electrical current into muscles and TrPs, with recent studies suggesting it may amplify the therapeutic effects of dry needling peripherally and centrally. This could be advantageous for patients with migraine and symptomatic TrPs. Materials and Methods: This study will implement a multiple baseline single-case experimental design (SCED). In a clinical setting, a SCED study lends itself to conducting research with only a few patients that each serve as their own controls. In this SCED study, four participants with chronic migraine will be enrolled in a non-concurrent manner and randomized to one of four baseline measurement periods (4, 5, 6 or 7 weeks), leading to four potentially different start dates for each participant in the intervention phase. During the intervention phase, patients will receive five sessions of dry needling with IMES, one session per week for five weeks. The primary outcome measure will be headache frequency, i.e., the reduction in the number of headache days over a one-month period using electronic headache diary data from the Migraine Buddy smartphone application. Secondary outcome measures will be changes in mean migraine pain intensity using a numeric pain rating scale (NPRS), migraine disability using the Migraine Disability Assessment Test (MIDAS), the Headache Impact Test (HIT-6), and changes in selected cervical musculoskeletal impairments including pressure pain thresholds (PPTs) over TrPs, the craniocervical flexion test (CCFT), and cervical active range of motion (AROM). Primary and secondary outcome measures will be analyzed separately using both visual and statistical analyses. Results: Actively recruiting participants. This project was approved by the Mass General Brigham Institutional Review Board (protocol #2023P000931) and is registered with ClinicalTrials.gov (NCT05893914). Conclusions: This study will seek to determine the effects of a five-week intervention period of IMES to TrPs in the posterior cervical muscles of subjects with chronic migraine.
Perfluorosulfonic Acid Membranes with Short and Long Side Chains and Their Use in Sensors for the Determination of Markers of Viral Diseases in Saliva
Authors: Parshina Anna V. , Safronova Ekaterina Yu. , Novikova Svetlana A. , Stretton Nastasia , Yelnikova Anastasia S. , Zhuchkov Timur R. , Bobreshova Olga V. , Yaroslavtsev Andrey B.
Published: July 2023

The development of accessible express methods to determine markers of viral diseases in saliva is currently an actual problem. Novel cross-sensitive sensors based on Donnan potential with bio-comparable perfluorosulfonic acid membranes for the determination of salivary viral markers (N-acetyl-L-methionine, L-carnitine, and L-lysine) were proposed. Membranes were formed by casting from dispersions of Nafion or Aquivion in N-methyl-2-pyrollidone or in a mixture of isopropyl alcohol and water. The influence of the polymer equivalent weight and the nature of dispersing liquid on water uptake, ion conductivity, and slope of Donnan potential for the membranes in H+ and Na+ form was investigated. The varying of the sorption and transport properties of perfluorosulfonic acid membranes provided a change in the distribution of the sensor sensitivity to N-acetyl-L-methionine, L-carnitine, and L-lysine ions, which was necessary for multisensory system development. The simultaneous determination of three analytes, and the group analysis of them in artificial saliva solutions, was performed. The errors of N-acetyl-L-methionine and L-carnitine determination were 4–12 and 3–11%, respectively. The determination of L-lysine was complicated by its interaction with Ca2+ ions. The error of the group analysis was no greater than 9%. The reverse character of the viral markers’ sorption by the membranes provided long-term sensor operation.
Effect of Operating Parameters on the Performance of Integrated Fixed-Film Activated Sludge for Wastewater Treatment
Authors: Waqas Sharjeel , Harun Noorfidza Yub , Sambudi Nonni Soraya , Abioye Kunmi Joshua , Zeeshan Muhammad Hamad , Ali Abulhassan , Abdulrahman Aymn , Alkhattabi Loai , Alsaadi Ahmad S.
Published: July 2023

Integrated fixed-film activated sludge (IFAS) is a hybrid wastewater treatment process that combines suspended and attached growth. The current review provides an overview of the effect of operating parameters on the performance of IFAS and their implications for wastewater treatment. The operating parameters examined include hydraulic retention time (HRT), solids retention time (SRT), dissolved oxygen (DO) levels, temperature, nutrient loading rates, and aeration. Proper control and optimization of these parameters significantly enhance the treatment efficiency and pollutant removal. Longer HRT and appropriate SRT contribute to improved organic matter and nutrient removal. DO levels promote the growth of aerobic microorganisms, leading to enhanced organic matter degradation. Temperature influences microbial activity and enzymatic reactions, impacting treatment efficiency. Nutrient loading rates must be carefully managed to avoid system overload or inhibition. Effective aeration ensures uniform distribution of wastewater and biofilm carriers, optimizing contact between microorganisms and pollutants. IFAS has been used in water reuse applications, providing a sustainable and reliable water source for non-potable uses. Overall, IFAS has proven to be an effective and efficient treatment process that can provide high-quality effluent suitable for discharge or reuse. Understanding the effects of these operating parameters helps to optimize the design and operation for efficient wastewater treatment. Further research is needed to explore the interactions between different parameters, evaluate their impact under varying wastewater characteristics, and develop advanced control strategies for improved performance and sustainability.
Vacuum Brazing and Performance Evaluation of T2 Copper Block and 316L Stainless Steel Tube
Authors: Wang Yu , Shang Qiao , Zeng Jing , Hou Ailin , Wang Xiaoxia , Wang Yafeng
Published: July 2023

The International Thermonuclear Experiment Reactor (ITER) Thermal shield (TS) serves as a cryogenic heat exchanger to maintain the thermal stability of the ITER superconducting magnet coil, which is critical to the control of the plasma during the operation of the ITER device. The TS is composed of long-length 316L stainless steel (SS) and copper as brazed joints. In this case, a feasible fabrication design for the CCS TS is presented, accomplished by three kinds of joining processes (vacuum brazing, friction stir weld, and TIG weld). In the reliable fabrication design, the brazing quality of the as-brazed long-distance 316L SS and copper joints plays a critical role in the thermal conductivity performance of the ITER thermal shield. Therefore, a high-quality vacuum brazing process of long-length SS/Cu joints applied in a low-temperature superconductor magnet system was first studied. The macro metallography analysis demonstrates the braze ratio of the samples is 100%, and no crack or defect is observed in the samples. The microstructural characterization reveals the brazing seams are composed of silver-based Ag-rich eutectic. The micro-shear test indicates that the shear strength of the 316L tube and copper joint is 205 MPa, with the fracture position located on the copper side; this zone will be the most vulnerable zone of the joints. In addition, the SEM results illustrated that the shear fracture morphology displayed a ductile fracture feature. The test results demonstrated that the highly precise depth drilling employed in this paper ensured a good control of the brazing clearance, resulting in a 100% braze ratio for the long-length SS/Cu joints. Therefore, it can be concluded that the brazing process can be applied in the ITER TS for the good thermal conductivity performance of long-length SS/Cu-brazing joints.
Effect of CaO Addition on Microstructural Evolution Due to the Annealing of AZ31 Alloys Processed by Equal-Channel Angular Pressing (ECAP)
Authors: Bae Seong-Hwan , Shin Young-Chul , Lee Ji-Woon , Jung Ki-Ho , Hyun Soong-Keun
Published: July 2023

This study demonstrated the application of equal-channel angular processing (ECAP), which was performed via the BC route, to determine the effect of the addition of CaO on the microstructural evolution of an AZ31 alloy due to annealing. Compression tests were performed to evaluate the mechanical properties of the alloy, and the corresponding microstructures were observed to elucidate the flow behavior. Ca-bearing second-phase particles were fragmented with the increase in the number of ECAP passes. The increase in the yield strength and flow stress with the addition of CaO was attributed to the dispersion of the Ca-bearing second-phase particles. When the CaO-added AZ31 and commercial AZ31 alloys were subjected to annealing, their flow stress decreased owing to the grain growth. However, the extent of the decrease in the flow stress for the CaO-added AZ31 alloy was lower than that for the commercial AZ31 alloy.
Layout Dependence Stress Investigation in through Glass via Interposer Architecture Using a Submodeling Simulation Technique and a Factorial Design Approach
Authors: Wang Shih-Hung , Hsu Wensyang , Liou Yan-Yu , Huang Pei-Chen , Lee Chang-Chun
Published: July 2023

The multi-chiplet technique is expected to be a promising solution to achieve high-density system integration with low power consumption and high usage ratio. This technique can be integrated with a glass interposer to accomplish a competitive low fabrication cost compared with the silicon-based interposer architecture. In this study, process-oriented stress simulation is performed by the element activation and deactivation technique in finite element analysis architecture. The submodeling technique is also utilized to mostly conquer the scale mismatch and difficulty in mesh gridding design. It is also used to analyze the thermomechanical responses of glass interposers with chiplet arrangements and capped epoxy molding compounds (EMC) during curing. A three-factor, three-level full factorial design is applied using the analysis of variance method to explore the significance of various structural design parameters for stress generation. Analytic results reveal that the maximum first principal stresses of 130.75 and 17.18 MPa are introduced on the sidewall of Cu-filled via and the bottom of the glass interposer, respectively. Moreover, the EMC thickness and through glass via pitch are the dominant factors in the adopted vehicle. They significantly influence the stress magnitude during heating and cooling.
Design of a Ka-Band Five-Bit MEMS Delay with a Coplanar Waveguide Loaded U-Shaped Slit
Authors: Zhan Yongxin , Chen Yu , Guo Honglei , Wu Qiannan , Li Mengwei
Published: July 2023

This paper designs a five-bit microelectromechanical system (MEMS) time delay consisting of a single-pole six-throw (SP6T) RF switch and a coplanar waveguide (CPW) microstrip line. The focus is on the switch upper electrode design, power divider design, transmission line corner compensation structure design, CPW loading U-shaped slit structure design, and system simulation. The switch adopts a triangular upper electrode structure to reduce the cantilever beam equivalent elastic coefficient and the closed contact area to achieve low drive voltage and high isolation. The SP6T RF MEMS switch uses a disc-type power divider to achieve consistent RF performance across the output ports. When designed by loading U-shaped slit on transmission lines and step-compensated tangents at corners, the system loss is reduced, and the delay amount is improved. In addition, the overall size of the device is 2.1 mm × 2.4 mm × 0.5 mm, simulation results show that the device has a delay amount of 0–60 ps in the frequency range of 26.5–40 GHz, the delay accuracy at the center frequency is better than 0.63 ps, the delay error in the whole frequency band is less than 22.2%, the maximum insertion loss is 3.69 dB, and the input–output return rejection is better than 21.54 dB.
Characterization of Residual Stress in SOI Wafers by Using MEMS Cantilever Beams
Authors: Yang Haotian , Liu Min , Zhu Yingmin , Wang Weidong , Qin Xianming , He Lilong , Jiang Kyle
Published: July 2023

Silicon-on-insulator (SOI) wafers are crucial raw materials in the manufacturing process of microelectromechanical systems (MEMS). Residual stresses generated inside the wafers during the fabrication process can seriously affect the performance, reliability, and yield of MEMS devices. In this paper, a low-cost method based on mechanical modeling is proposed to characterize the residual stresses in SOI wafers in order to calculate the residual stress values based on the deformation of the beams. Based on this method, the residual strain of the MEMS beam, and thus the residual stress in the SOI wafer, were experimentally determined. The results were also compared with the residual stress results calculated from the deflection of the rotating beam to demonstrate the validity of the results obtained by this method. This method provides valuable theoretical reference and data support for the design and optimization of devices based on SOI-MEMS technology. It provides a lower-cost solution for the residual stress measurement technique, making it available for a wide range of applications.
Full Complex-Amplitude Modulation of Surface Waves Based on Spin-Decoupled Metasurface
Authors: Li Quan , Wu Chao , Xie Yu , Li Song , Li Hongqiang , Jin Lijun
Published: July 2023

This work proposes a method for surface wave (SW) coupling along with flexible complex amplitude modulation of its wavefront. The linearly polarized incident plane wave is coupled into the surface mode with complex wavefront by exploiting the spin-decouple nature of a reflective chiral meta-atom. As verification, two kinds of metasurface couplers are designed. The first kind contains two examples for SW airy beam generation with and without deflection under linearly polarized illumination, respectively. The second kind is a bi-functional device capable of SW focusing under left-handed circularly polarized illumination, and propagating wave deflection under right-handed circularly polarized illumination, respectively, to verify the fundamental spin-decoupled character. Simulated and experimental results are in good agreement. We believe that this method provides a flexible approach for complex SW applications in integrated optics, optical sensing, and other related fields.
Recent Advances in Precision Diamond Wire Sawing Monocrystalline Silicon
Authors: Li Ansheng , Hu Shunchang , Zhou Yu , Wang Hongyan , Zhang Zhen , Ming Wuyi
Published: July 2023

Due to the brittleness of silicon, the use of a diamond wire to cut silicon wafers is a critical stage in solar cell manufacturing. In order to improve the production yield of the cutting process, it is necessary to have a thorough understanding of the phenomena relating to the cutting parameters. This research reviews and summarizes the technology for the precision machining of monocrystalline silicon using diamond wire sawing (DWS). Firstly, mathematical models, molecular dynamics (MD), the finite element method (FEM), and other methods used for studying the principle of DWS are compared. Secondly, the equipment used for DWS is reviewed, the influences of the direction and magnitude of the cutting force on the material removal rate (MRR) are analyzed, and the improvement of silicon wafer surface quality through optimizing process parameters is summarized. Thirdly, the principles and processing performances of three assisted machining methods, namely ultrasonic vibration-assisted DWS (UV-DWS), electrical discharge vibration-assisted DWS (ED-DWS), and electrochemical-assisted DWS (EC-DWS), are reviewed separately. Finally, the prospects for the precision machining of monocrystalline silicon using DWS are provided, highlighting its significant potential for future development and improvement.
Impact of Nitridation on Bias Temperature Instability and Hard Breakdown Characteristics of SiON MOSFETs
Authors: Tyaginov Stanislav , O’Sullivan Barry , Chasin Adrian , Rawal Yaksh , Chiarella Thomas , de Carvalho Cavalcante Camila Toledo , Kimura Yosuke , Vandemaele Michiel , Ritzenthaler Romain , Mitard Jerome , Palayam Senthil Vadakupudhu , Reifsnider Jason , Kaczer Ben
Published: July 2023

We study how nitridation, applied to SiON gate layers, impacts the reliability of planar metal-oxide-semiconductor field effect transistors (MOSFETs) subjected to negative and positive bias temperature instability (N/PBTI) as well as hard breakdown (HBD) characteristics of these devices. Experimental data demonstrate that p-channel transistors with SiON layers characterized by a higher nitrogen concentration have poorer NBTI reliability compared to their counterparts with a lower nitrogen content, while PBTI in n-channel devices is negligibly weak in all samples independently of the nitrogen concentration. The Weibull distribution of HBD fields extracted from experimental data in devices with a higher N density are shifted towards lower values with respect to that measured in MOSFETs, and SiON films have a lower nitrogen concentration. Based on these findings, we conclude that a higher nitrogen concentration results in the aggravation of BTI robustness and HBD characteristics.
Experimental Study on the Compatibility of PD Flexible UHF Antenna Sensor Substrate with SF6/N2
Authors: Hu Xukun , Zhang Guozhi , Deng Guangyu , Li Xuyu
Published: July 2023

The use of flexible, built-in, ultra-high-frequency (UHF) antenna sensors is an effective method to solve the weak high-frequency electromagnetic wave signal sensing of partial discharge (PD) inside gas-insulated switchgears (GISs), and the compatibility of flexible UHF antenna sensor substrate materials and SF6/N2 mixtures is the key to the realization of a flexible UHF antenna sensor inside a GIS. Based on this, this paper builds an experimental platform for the compatibility of a 30% SF6/70% N2 gas mixture and a PD flexible UHF antenna sensor substrate and conducts compatibility experiments between the 30% SF6/70% N2 gas mixture and PD flexible UHF antenna sensor substrate under different temperatures in combination with the actual operating temperature range of the GIS. In this article, a Fourier transform infrared spectrometer, scanning electron microscope and X-ray photoelectron spectrometer were used to test and analyze the gas composition, the surface morphology and the elemental change in the PD flexible UHF antenna sensor substrate, respectively. PET material will be slightly oxidized under the environment of a 30% SF6/70% N2 gas mixture at 110 °C, PI material will generate metal fluoride under the environment of a 30% SF6/70% N2 gas mixture and only PDMS material will remain stable under the environment of a 30% SF6/70% N2 gas mixture; therefore, it is appropriate to use PDMS substrate in the development of flexible UHF antenna sensors.
Formation of Paramagnetic Defects in the Synthesis of Silicon Carbide
Authors: Mukesh Nain , Márkus Bence G. , Jegenyes Nikoletta , Bortel Gábor , Bezerra Sarah M. , Simon Ferenc , Beke David , Gali Adam
Published: July 2023

Silicon carbide (SiC) is a very promising platform for quantum information processing, as it can host room temperature solid state defect quantum bits. These room temperature quantum bits are realized by paramagnetic silicon vacancy and divacancy defects in SiC that are typically introduced by irradiation techniques. However, irradiation techniques often introduce unwanted defects near the target quantum bit defects that can be detrimental for the operation of quantum bits. Here, we demonstrate that by adding aluminum precursor to the silicon and carbon sources, quantum bit defects are created in the synthesis of SiC without any post treatments. We optimized the synthesis parameters to maximize the paramagnetic defect concentrations—including already established defect quantum bits—monitored by electron spin resonance spectroscopy.
E7 Oncogene HPV58 Variants Detected in Northeast Brazil: Genetic and Functional Analysis
Authors: Chagas Bárbara Simas , Tibúrcio Júnior Elias , Silva Ruany Cristyne de Oliveira , Santos Daffany Luana dos , Barros Junior Marconi Rego , Lima Rita de Cássia Pereira de , Invenção Maria da Conceição Viana , Santos Vanessa Emanuelle Pereira , França Neto Pedro Luiz , Silva Júnior Antônio Humberto , Silva Neto Jacinto Costa , Batista Marcus Vinícius de Aragão , Freitas Antonio Carlos de
Published: July 2023

Cervical cancer is associated with persistent infections by high-risk Human Papillomavirus (HPV) types that may have nucleotide polymorphisms and, consequently, different oncogenic potentials. Therefore, this study aimed to evaluate the genetic variability and structural effects of the E7 oncogene of HPV58 in cervical scraping samples from Brazilian women. The study was developed with patients from hospitals in the metropolitan area of Recife, PE, Brazil. The most frequent HPV types were, in descending order of abundance, HPV16, 31, and 58. Phylogenetic analysis demonstrated that the isolates were classified into sublineages A2, C1, and D2. Two positively selected mutations were found in E7: 63G and 64T. The mutations G41R, G63D, and T64A in the E7 protein reduced the stability of the protein structure. Utilizing an NF-kB reporter assay, we observed a decrease in the NK-kB pathway activity with the HPV58-E7 variant 54S compared to the WT E7. The other detected E7 HPV58 variants presented similar NF-kB pathway activity compared to the WT E7. In this study, it was possible to identify mutations that may interfere with the molecular interaction between the viral oncoproteins and host proteins.