bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Tempering Temperature on Microstructure and Properties of a New Type of Nitrogen‐Containing Hot‐Work Die Steel 3Cr7Mo2NiSiVN
Authors: Liu Fubin , Kang Congpeng , Qian Ruiqing , Jiang Zhouhua , Geng Xin , Li Huabing
Published: March 2022

Herein, the effect of tempering temperature on the microstructure evolution and mechanical properties of a new nitrogen‐containing hot‐work die steel 3Cr7Mo2NiSiVN is investigated. The new type of hot‐work die steel is quenched at 1080 °C and then conducts a double tempering from 200 to 700 °C. The quenching microstructure contains martensite, film‐retained austenite, and undissolved precipitates, and these precipitates play a Zener pinning effect role in prior austenite grains growing. Based on the Thermo‐Calc thermodynamic calculation and experimental results, the die steel contains V‐rich M2N nitride, Cr‐rich M23C6 carbide, Mo‐rich M6C carbide, and (Nb,V)‐rich M(C,N) precipitates. A secondary hardening phenomenon occurs and the brittle fracture turns to ductile fracture under the scanning electron microscope (SEM) field when the tempering temperature is 500 °C. Room strength decreases and the plasticity improves with the continual increase of tempering temperature. Many nano‐size spherical M2N nitride and strip‐like M(C,N) carbonitride precipitate when the tempered temperature exceeds 550 °C with transmission electron microscope (TEM) observation. Finely dispersed M2N nitride and M(C,N) carbonitride are beneficial for stabilizing microstructure at high temperatures and improving high‐temperature strength. Therefore, the high‐temperature strength of the new type of hot‐work die steel is much higher than that of the traditional hot‐work die steel.
Development and validation of liquid chromatography method for determination of Ibrutinib in finished dosage forms using quality by design approach
Authors: Konduru Naresh , Gundla Rambabu , Dongala Thirupathi , Katari Naresh Kumar , Mallavarapu Ravindra
Published: March 2022

A simple, precise, linear, robust, accurate, and stability‐indicating liquid chromatography method was developed and validated to determine Ibrutinib in finished solid dosage forms by reversed‐phase high‐performance liquid chromatography/photodiode array detector. Separation was achieved using a Luna C18 150 mm × 4.6 mm × 3.0 μm with a suitable mobile phase. The mobile phase: A consists of a 10 mM phosphate buffer concentration and 1 mL triethylamine, adjusted to pH 5.6 with a diluted orthophosphoric acid solution and acetonitrile in the ratio of 95:5 v/v to enhance the results. Moreover, mobile phase ‐ B contains 85% of acetonitrile. The optimized chromatographic conditions such as flow rate 1.0 mL/min, injection volume 10 μL, column temperature 40°C, and wavelength 258 nm. The proposed method is significant because it was developed by the Quality by Design approach. All impurities were identified, such as degradation and placebo impurities without interference at principle peak retention time. After development, it has been validated as per current regulatory guidelines. Obtained recovery between 98 and 102% at 50–200% level; linearity found (r2) = 0.9999 from 20 to 200% level; precision results achieved <2.0% relative standard deviation; and the robustness study results are found satisfactory. It's beneficial.
A machine‐learning‐based constitutive bond‐slip model for anchored CFRP strips externally bonded on concrete members
Authors: Kurtoğlu Ahmet Emin , Anil Özgür , Çevik Abdulkadir
Published: March 2022

Strengthening is often required for reinforced concrete, steel, and masonry structures or structural elements when they possess insufficient performance against external loads such as earthquakes. Recently, the use of carbon fiber‐reinforced polymers (CFRP) has been considered a viable strengthening technique alternative to traditional methods. The major concern is premature debonding failure hindering the efficient use of CFRP systems. FRP anchor systems have been used to avoid this phenomenon. This paper employs a machine learning (ML)‐based algorithm (support vector regression) to propose predictive models to simulate the bond‐slip behavior of anchored CFRP strips externally bonded to the concrete surface. A comprehensive database was constructed using the previous reports on the bond‐slip behavior of FRP‐to‐concrete joints anchored with CFRP strips. Afterwards, the collected database was used to train and validate the proposed models. The input parameters cover all possible factors, that is, compressive strength of concrete, width of concrete block, anchor hole diameter, anchor hole depth, number of anchors at one row, number of anchors at one column; elastic modulus, width, bonding length, and thickness of CFRP strip. The output parameters are maximum shear capacity, residual shear capacity, displacement values at peak shear, and residual shear. Results imply that the proposed models have high prediction accuracies with low error rates. Proposed models are also presented in code format to be easily incorporated into analysis software for practical use.
Phylogeography of the endangered orchids Cypripedium japonicum and Cypripedium formosanum in East Asia: Deep divergence at infra‐ and interspecific levels
Authors: Han Li Xia , Jin Yue , Zhang Jun Li , Li Xing Lin , Chung Mi Yoon , Herrando‐Moraira Sonia , Kawahara Takayuki , Yukawa Tomohisa , Chung Shih‐Wen , Chung Jae Min , Kim Young‐Dong , López‐Pujol Jordi , Chung Myong Gi , Tian Huai Zhen
Published: March 2022

To date, little is known about the past evolutionary trajectories of rare and endangered orchids native to mainland China, Japan, and Korea (the CJK region). In this study, we focus on two endangered orchids, Cypripedium japonicum (present in the three countries) and C. formosanum (endemic to Taiwan), to understand the divergence/speciation models that would have been operating in this group, including genetic diversity, geographic structure, and colonization pathways across the region. Using a combination of five cpDNA regions, we reconstructed phylogenetic trees and investigated the genetic diversity/structure of 20 populations. Ecological niche modeling was used to gain insight into the paleodistribution and dispersal corridors at the Last Glacial Maximum and to survey climatic niche differences. Populations from mainland China + Korea, Japan, and Taiwan formed three distinct monophyletic lineages and were placed into separate genetic clusters, agreeing with geographic barriers and species boundaries. Populations of C. japonicum in mainland China harbored the highest diversity, suggesting the presence of multiple glacial refugia. The Korean populations would have originated from either western/central or eastern China, probably using a dispersal corridor across the East China Sea shelf. The divergence of C. formosanum is proposed under an allopatric speciation model, also highly influenced by a climate niche shift. In the context of previous studies, a deep divergence in cpDNA sequences between Chinese + Korean and Japanese populations of C. japonicum may be taken as an example of the speciation events of the CJK flora since the late Neogene that have led to its current species richness.
Effects of mammalian target of rapamycin and aryl hydrocarbon receptor‐mediating autophagy signaling on the balance of Th17/Treg cells during perinatal bisphenol A exposure in female offspring mice
Authors: Gao Liang , Luo Dan , Wu Dan , Sun Qi , Liu Yang , Wen Deliang , Jia Lihong
Published: March 2022

Bisphenol A (BPA)'s immunotoxic properties have received increasing interest, which can lead to immune dysfunction and related disease development. However, the mechanism is not completely clear. A growing body of evidence suggests that autophagy has important roles in innate immunity, inflammatory response, and adaptive immunity. This study aimed to investigate the possible mechanisms of mammalian target of rapamycin (mTOR), aryl hydrocarbon receptor (AhR), and autophagy in Treg/Th17 imbalance induced by perinatal BPA exposure. Our results showed that the number of Th17 cells in the spleen of offspring female mice significantly increased, while the number of Treg cells decreased significantly, which was consistent with the expression levels of up‐regulation of RORγt protein and a down‐regulation Foxp3 protein. The levels of mTOR, p‐mTOR, P62, and AhR protein expression increased, and LC3 protein decreased in spleen. However, in the thymus, we found that RORγt and Foxp3 proteins changed most significantly in the low‐dose BPA group, and the same as p‐mTOR and P62 protein levels. We conjectured that the potential mechanism of the imbalance of Th17/Treg upon perinatal exposure to BPA was probably associated with autophagy dysfunction. Proper autophagy plays an important role in maintaining the homeostasis of the thymic and spleen immune system.
Synthesis, Anti‐migration and Catalytic Effect of Ferrocene Azine Derivatives on the Thermal Decomposition of Ammonia Perchlorate
Authors: Guo Huimin , Huo Da , Zhao Haiying , Chen Shufeng
Published: March 2022

Ferrocene burning rate catalyst (BRC) is a common catalyst to promote the combustion of composite solid propellant because of its high catalytic performance, but this kind of catalyst has the disadvantage of easy migration. Ammonia perchlorate (AP) is the main oxidant of composite solid propellant, and its thermal degradation behavior has an important impact on the combustion of propellant. New mononuclear and polynuclear ferroceneazine BRCs were synthesized, and their structures were characterized by UV‐Vis, NMR, HRMS and IR spectra. The catalytic effects of these ferrocenylazines on the thermal degradation of AP were studied by DSC and TG. The results confirmed that the catalytic performance of azine without bisferrocenylpropane was inferior to that of Catocene (Cat), while the catalytic performance of azine with bisferrocenylpropane was equivalent to that of Cat. Anti‐migration studies showed that both mononuclear ferroceneazines and Cat showed mobility, while polynuclear ferroceneazines did not migrate after long‐term storage. Therefore, polynuclear ferroceneazine is a new kind of high‐efficiency and non‐migration BRC with application prospects.
Cosmologies, singularities and quantum extremal surfaces
Authors: Goswami Kaberi , Narayan K. , Saini Hitesh K.
Published: March 2022

Abstract

Following [1], we study quantum extremal surfaces in various families of cosmologies with Big-Crunch singularities, by extremizing the generalized entropy in 2-dimensional backgrounds which can be thought of as arising from dimensional reduction. Focussing first on the isotropic AdS Kasner case, introducing a spatial regulator enables relating the locations in time of the quantum extremal surface and the observer. This shows that the quantum extremal surface lags behind the observer location. A potential island-like region, upon analysing more closely near the island boundary, turns out to be inconsistent. Similar results arise for other holographic cosmologies. We then study certain families of null Kasner singularities where we find that the quantum extremal surface can reach the near singularity region although the on-shell generalized entropy is generically singular. We also study other cosmologies including de Sitter (Poincare slicing) and FRW cosmologies under certain conditions.
Replica wormholes and the black hole interior
Authors: Penington Geoff , Shenker Stephen H. , Stanford Douglas , Yang Zhenbin
Published: March 2022

Abstract

Recent work has shown how to obtain the Page curve of an evaporating black hole from holographic computations of entanglement entropy. We show how these computations can be justified using the replica trick, from geometries with a spacetime wormhole connecting the different replicas. In a simple model, we study the Page transition in detail by summing replica geometries with different topologies. We compute related quantities in less detail in more complicated models, including JT gravity coupled to conformal matter and the SYK model. Separately, we give a direct gravitational argument for entanglement wedge reconstruction using an explicit formula known as the Petz map; again, a spacetime wormhole plays an important role. We discuss an interpretation of the wormhole geometries as part of some ensemble average implicit in the gravity description.
Evaluation of digital construction, production and intraoral position accuracy of novel 3D CAD/CAM titanium retainers
Authors: Koller S. , Craveiro R. B. , Niederau C. , Pollak T. L. , Knaup I. , Wolf M.
Published: March 2022

Objectives

New opportunities have arisen to manufacture three-dimensional computer-aided design/computer-aided manufacturing (3D CAD/CAM) retainers from titanium blocks by digital cutting technology. These novel technologies need to fulfill requirements regarding digital planning and position accuracy. The aim of the present study was to investigate the digital construction, the CAD/CAM production and the intraoral positioning accuracy of custom-manufactured novel 3D CAD/CAM titanium retainers.

Materials and methods

A total of 37 prime4me® RETAIN3R (Dentaurum, Ispringen, Germany) retainers were inserted to stabilize the upper anterior front teeth. Following insertion, an intraoral scan was used to record the position. The intraoral position was compared to the virtual setup using 3D superimposition software. Measurement points were evaluated in all three dimensions (horizontal, sagittal and vertical planes). Data were analyzed using Kruskal–Wallis test followed by Dunn’s multiple comparison test.

Results

A total of 185 measurements were performed. The horizontal plane and the sagittal plane demonstrated a high level of positioning accuracy between the planned and the intraoral position. Statistically significant deviations between the preceding virtual setup and the intraoral situation were observed in the vertical dimension. Within the retainer, the intraoral positioning accuracy decreased for the measurement points in the direction of the distal retainer segment.

Conclusion

Based on the results, the present study shows a high level of congruence between the 3D virtually planning and the final intraoral position of the fabricated novel 3D CAD/CAM titanium retainers.
Iatrogenic injury of the popliteal artery in orthopedic knee surgery: clinical results and development of a therapeutic algorithm
Authors: Gosslau Yvonne , Warm Tobias Dominik , Foerch Stefan , Zerwes Sebastian , Scheurig-Muenkler Christian , Hyhlik-Duerr Alexander
Published: March 2022

Purpose

Intraoperative injury to the popliteal artery is a rare complication of orthopedic surgery, however, it can have serious consequences, including major amputation. Recommendations for a standard approach are lacking. The aim of this study was to develop an interdisciplinary therapeutic algorithm to assist in complication management.

Methods

From 01/11 to 12/20, 16 arterial injuries after knee surgery were analyzed in a retrospective single-center study. Four cases involved recurrent orthopedic surgery. Procedures performed included eleven total knee arthoplasties (TKA), two TKA replacements, one arthroscopy, and two high tibial osteotomies. Clinical presentation of patients was hemorrhage (n = 2), ischemia (n = 7), the combination of both (n = 4), or pseudoaneurysm formation (n = 3).

Results

Ten patients underwent endovascular treatment, some as combined procedures: (stent)-PTA (n = 6), aspiration thrombectomy (n = 5), thrombin injection (n = 1), and embolization (n = 1). Six patients were treated surgically: four with bypass/interposition and one with a patch plasty and one as a hybrid procedure, respectively. Only autologous great saphenous vein was used. All extremities could be preserved. Functional impairment remained in six cases.

Conclusion

Both endovascular and surgical procedures can be used to treat arterial injuries after knee surgery. Efficient standardized diagnosis and the involvement of vascular expertise are essential to prevent functional impairment or limb loss, as suggested in the algorithms.
Epiphysiodesen und Hemiepiphysiodesen
Authors: Willegger Madeleine , Bouchard Maryse , Windhager Reinhard , Kolb Alexander , Chiari Catharina
Published: March 2022

Durch das Prinzip der Wachstumsblockade mittels Epiphysiodese und der Wachstumslenkung durch Hemiepiphysiodese können sowohl Beinlängendifferenzen als auch sagittale, koronare und schräge Achsdeformitäten an der unteren Extremität während des Wachstums korrigiert werden. Es werden temporäre und permanente Techniken unterschieden. Der große Vorteil liegt in der minimal-invasiven Anwendung und den geringen Komplikationen. Essenziell sind die genaue Planung sowie das exakte Timing, besonders wenn permanente Verfahren angewandt werden. Die Anwendung rund um das kindliche Kniegelenk kann als Goldstandard der Behandlung von Beinlängendifferenzen und Varus- und Valguskorrekturen bezeichnet werden. Die Wachstumslenkung an der unteren Extremität hat über die letzten Jahre viele neue Einsatzmöglichkeiten an der Hüfte und am Sprunggelenk gefunden. Die erfolgreichen klinischen Ergebnisse mit geringen Komplikationen unterstützen die breite Anwendung der Hemiepiphysiodese und Epiphysiodese am wachsenden Skelett bei Achsfehlstellungen und Beinlängendifferenzen.
T2 mapping for the characterization of prostate lesions
Authors: Hepp Tobias , Kalmbach Laura , Kolb Manuel , Martirosian Petros , Hilbert Tom , Thaiss Wolfgang M. , Notohamiprodjo Mike , Bedke Jens , Nikolaou Konstantin , Stenzl Arnulf , Kruck Stephan , Kaufmann Sascha
Published: March 2022

Purpose

Purpose of this study is to evaluate the diagnostic accuracy of quantitative T2/ADC values in differentiating between PCa and lesions showing non-specific inflammatory infiltrates and atrophy, features of chronic prostatitis, as the most common histologically proven differential diagnosis.

Methods

In this retrospective, single-center cohort study, we analyzed 55 patients suspected of PCa, who underwent mpMRI (3T) including quantitative T2 maps before robot-assisted mpMRI-TRUS fusion prostate biopsy. All prostate lesions were scored according to PI-RADS v2.1. Regions of interest (ROIs) were annotated in focal lesions and normal prostate tissue. Quantitative mpMRI values from T2 mapping and ADC were compared using two-tailed t tests. Receiver operating characteristic curves (ROCs) and cutoff were calculated to differentiate between PCa and chronic prostatitis.

Results

Focal lesions showed significantly lower ADC and T2 mapping values than normal prostate tissue (p < 0.001). PCa showed significantly lower ADC and T2 values than chronic prostatitis (p < 0.001). ROC analysis revealed areas under the receiver operating characteristic curves (AUCs) of 0.85 (95% CI 0.74–0.97) for quantitative ADC values and 0.84 (95% CI 0.73–0.96) for T2 mapping. A significant correlation between ADC and T2 values was observed (r = 0.70; p < 0.001).

Conclusion

T2 mapping showed high diagnostic accuracy for differentiating between PCa and chronic prostatitis, comparable to the performance of ADC values.
Revisiting the Hydraulics of the Aznalcóllar Mine Disaster
Authors: Sanz-Ramos Marcos , Bladé Ernest , Dolz Josep , Sánchez-Juny Martí
Published: March 2022

The Aznalcóllar tailings pond failure (1998) is regarded as one of the severe ecological mine disasters ever reported. The spill of the mine tailings affected more than 60 km of the Agrio and Guadiamar rivers and caused major environmental damage. Despite the event being well-documented with more than 400 scientific publications, including two special issues and two reviews, several hydraulic uncertainties and inconsistencies remain. This paper conducts a state-of-the-art review of the most relevant hydraulic aspects of the mine disaster. It addresses the pond and fluid characteristics, the break type, the breaking time, the flow propagation, the volume potentially stored and subsequently spilled, area dimensions affected by the spill, and the morphological changes generated in the river and riverbanks caused by the spill, and later on by the restoration activities. Several discrepancies and plenty of controversial data have been unearthed that may affect general understanding of the event. In addition, new data is introduced and analysed applying photointerpretation and digital terrain analysis techniques, aiming to derive in essential hydraulic parameters. The most important findings are that the spill could have had a volume about 11.5 hm3, affecting about 86.7 km of river length, twice the most referenced values in the literature, and that applied restoration activities have substantially modified the hydro-sedimentary processes of the affected system. Additionally, a first video observation-based classification reveals that the fluid behaved more like a highly concentrated sediment-laden flow than like a mud flow.
Seismic behaviour of high-rise frame-core tube structures considering dynamic soil–structure interaction
Authors: Zhang Xiaofeng , Far Harry
Published: March 2022

As the population grows and land prices rise, high-rise buildings are becoming more and more common and popular in urban cities. The traditional high-rise building design method generally assumes the structure is fixed at the base because the influence of soil–structure interaction is considered to be beneficial to the response of structures under the earthquake excitation. However, recent earthquakes and studies indicated that SSI may exert detrimental effects on commonly used structural systems. In this study, a numerical soil–structure model is established in Abaqus software to explore the impacts of SSI on high-rise frame-core tube structures. The seismic response of frame-core tube structures with various structural heights, height–width ratios, foundation types and soil types is studied. The numerical simulation results including maximum lateral deflections, foundation rocking, inter-storey drifts and base shears of rigid-base and flexible-base buildings are discussed and compared. The results reveal the lateral displacement and inter-storey drifts of the superstructure can be amplified when SSI is taken into account, while the base shears are not necessarily reduced. Increasing the stiffness of the foundation and the subsoil can generally increase the seismic demand of structures. It has been concluded that it is neither safe nor economical to consider only the beneficial effects of SSI or to ignore them in structural design practice.
Potential of biosynthesized zinc oxide nanoparticles to control Fusarium wilt disease in eggplant (Solanum melongena) and promote plant growth
Authors: Abdelaziz Amer M. , Salem Salem S. , Khalil Ahmed M. A. , El-Wakil Deiaa A. , Fouda Hossam M. , Hashem Amr H.
Published: March 2022

In this study, a novel, non-toxic, eco-friendly zinc oxide nanoparticles (ZnO-NPs) was used instead of the synthetic fungicides widely used to control the destructive phytopathogenic fungus Fusarium oxysporum, the causative agent of wilt disease in Solanum melongena L. Herein, the biosynthesized ZnO-NPs was carried out by Penicillium expansum ATCC 7861. In vitro, mycosynthesized ZnO-NPs exhibited antifungal activity against Fusarium oxysporum. In vivo, ZnO-NPs suppressed Fusarium wilt disease in cultivated Solanum melongena L. by decreasing the disease severity with 75% of plant protection. Moreover, ZnO-NPs stimulated the recovery of eggplant as an indicated by improving of morphological and metabolic indicators including plant height(152.5%), root length(106.6%), plant fresh biomass (146%), chlorophyll a (102.8%), chlorophyll b (67.86%), total soluble carbohydrates (48.5%), total soluble protein (81.8%), phenol (10.5%), antioxidant activity and isozymes compared with infected control. Therefore, this study suggests using mycosynthesized ZnO-NPs as an alternative to synthetic fungicides not only to eradicate the Fusarium wilt disease in cultivated eggplant (Solanum melongena) but also to promote the growth parameters and metabolic aspects.
Novel features for time series analysis: a complex networks approach
Authors: Silva Vanessa Freitas , Silva Maria Eduarda , Ribeiro Pedro , Silva Fernando
Published: March 2022

Being able to capture the characteristics of a time series with a feature vector is a very important task with a multitude of applications, such as classification, clustering or forecasting. Usually, the features are obtained from linear and nonlinear time series measures, that may present several data related drawbacks. In this work we introduceNetFas an alternative set of features, incorporating several representative topological measures of different complex networks mappings of the time series. Our approach does not require data preprocessing and is applicable regardless of any data characteristics. Exploring our novel feature vector, we are able to connect mapped network features to properties inherent in diversified time series models, showing thatNetFcan be useful to characterize time data. Furthermore, we also demonstrate the applicability of our methodology in clustering synthetic and benchmark time series sets, comparing its performance with more conventional features, showcasing howNetFcan achieve high-accuracy clusters. Our results are very promising, with network features from different mapping methods capturing different properties of the time series, adding a different and rich feature set to the literature.
A novel role-mapping algorithm for enhancing highly collaborative access control system
Authors: Abdelfattah Doaa , Hassan Hesham A. , Omara Fatma A.
Published: March 2022

The collaboration among different organizations is considered one of the main benefits of moving applications and services to a cloud computing environment. Unfortunately, this collaboration raises many challenges such as the access of sensitive resources by unauthorized people. Usually, Role-Based Access-Control (RBAC) model is deployed in large organizations. This paper addresses the scalability problem of the online stored rules. This problem affects the performance of the access control system due to increasing number of shared resources and/or number of collaborating organizations in the same cloud environment. Therefore, this paper proposes replacing the cross-domain RBAC rules with Role-To-Role (RTR) mapping rules among all organizations. The RTR mapping rules are generated using a newly proposed Role-Mapping algorithm. A comparative study is performed to evaluate the proposed algorithm’s performance with concerning the Rule-Store size and the authorization response time. According to the results, it is found that the proposed algorithm reduces the number of stored rules which minimizes the Rule-Store size and reduces the authorization response time. Additionally, this paper proposes applying a concurrent approach on the RTR mapping model using the proposed Role-Mapping algorithm to achieve more savings in the authorization response time. Therefore, it will be suitable in highly-collaborative cloud environments.
Applying novel methods in conventional activated sludge plants to treat low-strength wastewater
Authors: Latif E. F.
Published: March 2022

Conventional activated sludge system is confidently widely used for biological treatment plants of municipal wastewater but suffering from operation problems that affect their efficiencies and effluent qualities, especially when treating low-strength wastewater with increasing incoming flow. The objective of this study is to evaluate and compare the novel methods used in upgrading conventional activated sludge treatment systems receiving low-strength wastewater to generate good effluent quality. GPS-X Simulator V 8.0 was used for model calibration and plant performance prediction. The calibrated GPS-X model proved that eliminating primary settling from the treatment process does not affect BOD5 and COD removal, while TSS removal is decreased, and NH4-N removal is increased. Increasing the return activated sludge flow from 50 to 150% of influent flow does not affect conventional activated sludge process, while the change of waste activated flow had a vital effect on process performance. The presence of an anoxic zone in conventional activated sludge processes treating low-strength wastewater has no significant impact on plant performance. Also, the model outputs proved that adding filling media to the aeration tank was able to handle an increase of influent flow and a stable performance of BOD5, and NH4-N removal was observed.
Family Size and Parental Wealth: The Role of Family Transfers in Europe
Authors: Van Winkle Zachary , Monden Christiaan
Published: March 2022

As baby boomers enter retirement, an increasing portion of the population in Europe will rely on wealth as a source of financial security. We address two research questions: what is the association between family size, i.e. the number of children, and wealth for adults who are preparing for or have entered retirement and does the generosity of family transfers moderate that association? Data from the Survey of Health, Ageing, and Retirement in Europe (SHARE) are used to estimate the relationship between family size and the total household net worth of men and women between ages 50–65, born 1939–1967 from 14 European countries. We use logistic and linear regression modelling to investigate the probability of zero or negative wealth and net worth percentile rank. We find that adults with four or more children are more likely to be in debt and have less wealth than childless adults. In contrast, adults with two and three children have more wealth. We provide evidence that the generosity of family transfers ameliorates the negative association between larger family sizes and wealth, but may exacerbate wealth inequality by benefiting two and three child families most.
The thermal architecture of the ESA ARIEL payload at the end of phase B1
Authors: Morgante G. , Terenzi L. , Desjonqueres L. , Eccleston P. , Bishop G. , Caldwell A. , Crook M. , Drummond R. , Hills M. , Hunt T. , Rust D. , Puig L. , Tirolien T. , Focardi M. , Zuppella P. , Holmes W. , Amiaux J. , Czupalla M. , Rataj M. , Jessen N. C. , Pedersen S. M. , Pascale E. , Pace E. , Malaguti G. , Micela G.
Published: March 2022

The Atmospheric Remote-sensing Infrared Exoplanets Large-survey (ARIEL) is the fourth medium (M4) mission selected in the context of the ESA Cosmic Vision 2015–2025 programme, with a launch planned in 2028. During 4 years of flight operations, ARIEL will probe the chemical and physical properties of approximately 1000 known exoplanets by observing their atmosphere, to study how planetary systems form and evolve [1, 2]. The mission is designed as a transit and eclipse spectroscopy survey, operated by a 1-m class telescope feeding two instruments, the Fine Guidance system (FGS) and the ARIEL InfraRed Spectrometer (AIRS), that accommodate photometric and spectroscopic channels covering the band from 0.5 to 7.8 μm in the visible to near-IR range [3, 4]. The mission high sensitivity requirements ask for an extremely stable thermo-mechanical platform. The payload thermal control is based on a passive and active cooling approach. Passive cooling is achieved by a V-Groove shields system that exploits the L2 orbit favourable thermal conditions to cool the telescope and the optical bench to stable temperatures <60 K. The FGS focal planes operate at the optical bench temperature while the AIRS channel detectors require a colder reference, lower than 42 K. This is provided by an active cooling system based on a Neon Joule-Thomson cold end, fed by a mechanical compressor. In this paper we report the thermal architecture of the payload at the end of Phase B1 and present the requirements that drive the design together with the analyses results and the expected performances.
Between choices and “going with the flow”. Career guidance and Roma young people in Hungary
Authors: Bereményi Bálint Ábel
Published: March 2022

This paper enquires into how disadvantaged Hungarian Roma youth make decisions concerning their educational and early career trajectories, who guides them, and whether the main guidance agents and services are available to them particularly at the time of their school-to-work transition (STWT). Data was collected in a Hungarian city and its surroundings among 35 Roma young people between the ages of 18 and 30 through life-course interviews. In this paper, I analyse respondents’ life trajectories in respect of three forms of guidance they received, aiming to describe the mix of ‘substitute guidance’ Roma young people obtain, and its influence on their choices with respect to STWT. Findings suggest that the messy set of formal and informal guidance agents, services, and activities in Hungary tends to be contingent, discontinuous, segmented, non-specialized, and biased.
Small Size Transition-Edge Sensors for Future X-Ray Applications
Authors: Taralli E. , de Wit M. , Gottardi L. , Nagayoshi K. , Visser S. , Ridder M. L. , Akamatsu H. , Vaccaro D. , Bruijn M. P. , Gao J. R. , den Herder J-W
Published: March 2022

Large arrays of transition edge sensors (TESs) are the baseline for a number of future space observatories. For instance, the X-ray integral field unit (X-IFU) instrument on board the ATHENA space telescope will consist of $$\sim$$
∼
3000 TESs with high energy resolution ($$2\,{\mathrm{eV}}$$

2

eV

at X-ray energies up to 7 keV). In this contribution we report on the development of an X-ray TES array as a backup detector technology for X-IFU. The baseline readout technology for this mission is time domain multiplexing where the detectors are DC biased. Specifically, we report on the characterization of four different Ti/Au TESs with the following dimensions ($$\hbox {L}\times \hbox {W}$$

L
×
W

): $$30\times 15$$

30
×
15

, $$30\times 30$$

30
×
30

, $$50\times 25$$

50
×
25

and $$50\times 50\,\mu \hbox {m}^2$$

50
×
50

μ

m
2

, all of which are coupled to a $$2.3\,\mu \hbox {m}$$

2.3

μ
m

thick Au absorber of area $$240\times 240\,\mu \hbox {m}^2$$

240
×
240

μ

m
2

. We have performed our characterization using our standard frequency domain multiplexing readout connecting only pixels at low frequencies, where nonlinear effects due to the AC biasing are negligible. Promising energy resolution has been obtained, for instance $$1.78\pm 0.10\,\hbox {eV}$$

1.78
±
0.10

eV

and $$1.75\pm 0.10\,\hbox {eV}$$

1.75
±
0.10

eV

at 5.9 keV for the $$50\times 25$$

50
×
25

and $$50\times 50\,\mu \hbox {m}^2$$

50
×
50

μ

m
2

detectors respectively. Uniformity over a kilo-pixel array (of detectors with the same geometry) has been also studied, confirming the high quality of our fabrication process.
Variational Framework for Structure-Preserving Electromagnetic Particle-in-Cell Methods
Authors: Campos Pinto Martin , Kormann Katharina , Sonnendrücker Eric
Published: March 2022

In this article we apply a discrete action principle for the Vlasov–Maxwell equations in a structure-preserving particle-field discretization framework. In this framework the finite-dimensional electromagnetic potentials and fields are represented in a discrete de Rham sequence involving general finite element spaces, and the particle-field coupling is represented by a set of projection operators that commute with the differential operators. With a minimal number of assumptions which allow for a variety of finite elements and shape functions for the particles, we show that the resulting variational scheme has a general discrete Poisson structure and thus leads to a semi-discrete Hamiltonian system. By introducing discrete interior products we derive a second type of space discretization which is momentum preserving, based on the same finite elements and shape functions. We illustrate our method by applying it to spline finite elements, and to a new spectral discretization where the particle-field coupling relies on discrete Fourier transforms.
First- and Second-Order Optimality Conditions for Quadratically Constrained Quadratic Programming Problems
Authors: Flores-Bazán Fabián , Mastroeni Giandomenico
Published: March 2022

We consider a quadratic programming problem with quadratic cone constraints and an additional geometric constraint. Under suitable assumptions, we establish necessary and sufficient conditions for optimality of a KKT point and, in particular, we characterize optimality by using strong duality as a regularity condition. We consider in details the case where the feasible set is defined by two quadratic equality constraints and, finally, we analyse simultaneous diagonalizable quadratic problems, where the Hessian matrices of the involved quadratic functions are all diagonalizable by means of the same orthonormal matrix.
Practice and challenge of urban land governance: an empirical study in Tigrai, East Africa
Authors: Siyum Berihu Asgele
Published: March 2022

The purpose of the study was to assess the practices and challenges of urban land governance in the Tigrai Region. This study employed a concurrent nested design. Data were collected from 177 officeholders and customers through questionnaires. Besides, interviews were conducted with purposefully selected officeholders. The results of the data analysis were presented using mean, standard deviation, Pearson correlation, and logistic regression to see the relationship between the independent variables and the dependent variable. The major findings showed that the elements of good urban governance (participation, responsiveness, accountability, transparency, equity, and efficiency and effectiveness) are not practiced appropriately. The major challenges in good urban land governance are lack of resources, commitment, human resources, clear rules and regulations, modern service delivery, materials, budget, and rent-seeking behavior. As a result, citizens are not satisfied with the urban land governance system and implementation process. Thus, the government should reconsider strengthening urban land institutions.
Silicon Contamination During Alloy Oxidation in Water Vapour at 650 °C
Authors: Nguyen Thuan Dinh , Zhang Jianqiang , Young David J.
Published: March 2022

A model Si-free alloy, Fe-30Cr (wt.%), was exposed to Ar-10H2O mixture (in vol.%) at 650 °C, forming a protective Cr2O3 scale, which contained silica. Liquid water used to form water vapour in a bubbler was either deionised or distilled. In both cases, low-level water impurities of Si, F, Cl, S, and Ca matched those detected in the Cr2O3 scales by TEM/EDX and ToF–SIMS. Consideration of water droplet and residual solute particle sizes, together with Stokes’ Law shows that entrainment of Si in the gas stream is likely. Calculation of mass transfer rates from the gas to the growing chromia scale show that the amount of silica in the scale is accounted for. Many laboratory experiments could be affected in this way.
Live synthesis
Authors: Finkbeiner Bernd , Klein Felix , Metzger Niklas
Published: March 2022

Synthesis automatically constructs an implementation that satisfies a given logical specification. In this paper, we study the live synthesis problem, where the synthesized implementation replaces an already running system. In addition to satisfying its own specification, the synthesized implementation must guarantee a sound transition from the previous implementation. This version of the synthesis problem is highly relevant in “always-on” applications, where updates happen while the system is running. To specify the correct handover between the old and new implementation, we introduce an extension of linear-time temporal logic (LTL) called LiveLTL. A LiveLTL specification defines separate requirements on the two implementations and ensures that the new implementation satisfies, in addition to its own requirements, any obligations left unfinished by the old implementation. For specifications in LiveLTL, we show that the live synthesis problem can be solved within the same complexity bound as standard reactive synthesis, i.e., in 2EXPTIME. Our experiments show the necessity of live synthesis for LiveLTL specifications created from benchmarks of SYNTCOMP and robot control.
Medical physics services in radiology and nuclear medicine in Africa: challenges and opportunities identified through workforce and infrastructure surveys
Authors: Trauernicht Christoph , Hasford Francis , Khelassi-Toutaoui Nadia , Bentouhami Imen , Knoll Peter , Tsapaki Virginia
Published: March 2022

The International Atomic Energy Agency (IAEA) developed a staffing model to estimate the number of clinically qualified medical physicists (CQMP) that are required in an imaging facility, including diagnostic radiology and nuclear medicine. For the first time this staffing model was applied on a large scale across Africa. Within the framework of the IAEA African Regional Agreement (AFRA) Technical Cooperation (TC) project RAF6/053 entitled “Enhancing Capacity Building of Medical Physics to Improve Safety and Effectiveness of Medical Imaging (AFRA)”, a survey based on the IAEA staffing model was used to investigate the current CQMP workforce needs in imaging and radionuclide therapy in Africa in order to establish a baseline, identify gaps and suggest steps for improvement. The survey was open for five months, after which data verification was performed. 82 responses were received from 21 countries, including data from 97 diagnostic radiology and 40 nuclear medicine departments, as well as 75 interventional radiology departments and/or catheterization laboratories. Only 26·8% of centres employed an adequate number of CQMPs. The staffing model indicated that 134·3 CQMPs were required for these centres, but only 63 are currently employed in medical imaging and/or nuclear medicine at these centres. At least 11 countries do not have a single institution with an adequate number of CQMPs. Data analysis indicated that the number of radiology and nuclear medicine CQMPs is largely inadequate, at least by a factor of 20 in almost all countries in the region.
PDC bit optimization scheme for tight oil reservoirs in the Jidong Oilfield based on rock anti-drilling characteristics
Authors: Xiaofeng Xu , Wei Song , Kuanliang Zhu , Changhao Wang , Yan Zhou , Yunfeng Li , Shibin Li
Published: March 2022

The tight oil reservoir rocks in the Jidong Oilfield are generally characterized by high hardness, strong abrasiveness, and extremely unevenness, which seriously reduce the drilling efficiency. In view of this problem, the mineral composition, hardness, plasticity coefficient, and drillability of rocks were first determined. It was found that the rock integrity, compactness and high hardness are the main factors leading to the low rock breaking efficiency of PDC bits. Then, combined with logging data, the drilling resistance profile of the whole well section was established. According to the crushing mechanism of rocks under the action of a PDC bit, the mechanical model of a single composite plate under rock crushing conditions is established, and the influence of the back angle on the cutting force is analyzed. The flow field distribution of the drill bit surface under different nozzle combinations was calculated by finite element numerical simulation. Based on the experimental and simulation results, the optimal backward angle was 15°, and the optimal nozzle combination was two 16-mm central nozzles and five 14-mm peripheral nozzles. Finally, a personalized PDC bit design scheme for tight oil reservoirs in the Jidong Oilfield was proposed. The scheme includes the following: (1) a 5-blade straight-arc crown is profiled; (2) anti-impact cylindrical components are set; (3) the nozzle hydraulic structure adopts a bending type; and (4) the diameter-retaining teeth and diversion grooves are optimized. The optimized bit reduces stick–slip, improves stability, and has an obvious acceleration effect.
Meeting multiplicative thinking through thought-provoking tasks
Authors: Cheeseman Jill , Downton Ann , Ferguson Sarah , Roche Anne
Published: March 2022

Children’s multiplicative thinking as the recognition of equal group structures and the enumeration of the composite units was the subject of this research. In this paper, we provide an overview of the Multiplication and Division Investigations project. The results were obtained from a small sample of Australian children (n = 21) in their first year of school (mean age 5 years 6 months) who participated in a teaching experiment of five lessons taught by their classroom teacher. The tasks introduced children to the “equal groups” aspect of multiplication. A theoretical framework of constructivist learning, together with research literature underpinning early multiplicative thinking, tasks, and children’s thinking, was used to design the research. Our findings indicate that young children could imagine equal group structures and, in doing so, recognise and enumerate composite units. As the children came to these tasks without any prior formal instruction, it seemed that they had intuitive understandings of equal group structures based on their life experiences. We argue that the implications for teaching include creating learning provocations that elicit children’s early ideas of multiplication, visualisation, and abstraction. The research has also shown the importance of observing children, listening to their explanations of their thinking, and using insights provided by their drawings.
A novel strategy for high-throughput sample collection, analysis and visualization of explosives’ concentrations for contaminated areas
Authors: Kober S. L. , Schaefer P. , Hollert H. , Frohme M.
Published: March 2022

The use of explosives has led to a widespread distribution of 2,4,6-trinitrotoluene (TNT) and its by- and degradation products in the soil on former production and testing sites. The investigation of those large contaminated sites is so far based on a few selected soil samples, due to high costs of conventional HPLC and GC analysis, although huge differences in concentrations can already be found in small areas and different collection depths. We introduce a novel high-throughput screening system for those areas, which combines a smartphone-based collection of GPS data and soil characteristics with a fast MALDI-TOF MS quantification of explosives in soil sample extracts and finally a heatmap visualization of the explosives’ spread in soil and an analysis of correlation between concentrations and soil characteristics. The analysis of a 400 m2 area presented an extensive contamination with TNT and lower concentrations of the degradation and by-products aminodinitrotoluenes (ADNT) and dinitrotoluenes (DNT) next to a former production facility for TNT. The contamination decreased in deeper soil levels and depended on the soil type. Pure humus samples showed significantly lower contaminations compared to sand and humus/sand mixtures, which is likely to be caused by an increased binding potential of the humic material. No correlation was found between the vegetation and the concentration of explosives. Since the results were obtained and visualized within several hours, the MALDI-TOF MS based comprehensive screening and heatmap analysis might be valuable for a fast and high-throughput characterization of contaminated areas.