bluuebunny/crossref_metadata_2025 huggingface dataset:
Dry Sliding Wear Behavior of Austenitic Stainless Steel Material by Gas Nitriding Process
Authors: Sree K. Ramya , Raguraman D. , Saranya J. , Bain Animesh , Viswanth V. Srinivas , Aparna S. , Dhanush Ch. , Subbiah Ram
Published: October 2021

In industries, components must operate under extreme conditions such as high load, speed, temperature and chemical environment. Materials are selected according to commercial availability, cost and their properties such as strength, hardness, etc. AISI 904L is a high-alloy stainless steel with low carbon content, poor surface hardness and wear characteristics. Many engineering failures are caused by fatigue, corrosion, and poor wear resistance, begins at the surface level. This causes cracks in the surface, reducing the material’s life. The surfaces of the materials were subjected to severe thermal, chemical, and shock loads. The selected AISI 904L materials for this work were subjected to gas nitriding process and processed with 3 different time parameters such as 12 hours, 18 hours and 24 hours respectively and named as GN1, GN2 and GN3. The treatments were done at a constant temperature of 650°C. Gas nitriding, in comparison to other nitriding processes such as plasma and liquid nitriding, provides good dimensional stability, reduced deformation, and uniform case depth regardless of the size and shape of the specimen. To analyze the wear properties, a pin on a disc machine is used. Finally, metallographic studies were performed by scanning electron microscopy.
A Fuzzy Controlled LCC HVDC System with AC Voltage and Reactive Power Control
Authors: Anusha More , Padhan Dola Gobinda , Kumar D. Karuna
Published: October 2021

The main work focus is on the LCC HVDC reactive power control system with fluid regulated AC voltage. The reactive power and the voltage control capacity of LCC HVDC were examined and demonstrated with controlled condensers. Reactive power control and voltage management have been suggested and associated controllers with variable condensers have been developed on the reverse side of the fuzzy controlled LCC HVDC system. The active corrective side power control is required and a reactive or voltage control has been taken into account in this work. This study looks at the inverter side of the system LCC HVDC with customizable capacitors, reactive power and fluid management of the AC voltage. The usual AC voltage control and PI controller for reactive power is replaced by an injected controller that enhances reaction speed and control. In the MATLAB software with Sim-Power system toolbox, graphs are created using a GUI environment to model the proposed fuzzy-controlled HVDC system.
Comparison of EPS Geofoam and Stone columns in heave reduction of expansive soils
Authors: Jahnavi Thentu , Kranthi Kumar Kattamanchi V.
Published: October 2021

To reduce the swell pressures in expansive soils usually granular piles are used, but due to lack of availability there is need of a material which is highly compressible and economical also. EPS Geofoams are obtained by expanding the polystyrene polymer which is a by-product obtained from the petroleum industry. As the drainability of the Geofoam is very less a layer of Geocomposite is surrounded over the geofoam especially for allowing the drainage. So, the mechanism involved in the study is that whenever a saturated soil swells in vertical direction this Geofoam will give room to accommodate the lateral swell which leads to reduction in the vertical heave and Geocomposite will dissipate the excess pore pressure generated during swelling of the soil. In the present study an attempt was made to predict the performance of EPS Geofoam and Geocomposite in reducing the soil heave due to constant infiltration. A two dimensional (2D) numerical model was developed using GEOSTUDIO 2012 to predict the behaviour of the swelling soil due to the inclusion of Geofoams as well as stone columns. Generally coupled and uncoupled analysis are performed to study the behaviour of the swelling soil but as the uncoupled analysis is more advantageous than coupled analysis it is performed in the present study.
Mechanical properties of fly ash and blast furnace slag based alkali activated concrete using high silica modulus activator
Authors: Satyanarayana G.V.V. , Greeshma Kaparaboina
Published: October 2021

The alternative to cement is grabbing attention of inventors due to the numerous advantages with their usage. Fly Ash (FA) and Blast furnace slag (BFS) are abundantly available in bi product form. There is heavy problem in disposal and land availability for industries. So many studies are going on to reduce these problems by usage as cementitious materials in concrete adding advantages towards green concrete. It is developed that Alkali activated flyash concrete has high strength, high acid resistance and heat resistance where as Alkali activated slag concrete has rapid setting time, high strength, impermeable and improved fire resistance. In this study FA and BFS are activated with high silica modulus activator with different activator/binder ratios and binder contents. The alkali activated FA-BFS concrete is verified for workability, compressive strength, split tensile strength, and flexural strength.
Damage capacity on RC structures using performance based analysis
Authors: Spandana Kurelly , Raju Y.Kamala , Satyanarayana G V V , Manchalwar Atulkumar
Published: October 2021

Performance based analysis is conducted on a structure to know the performance of building under severe earthquake loads with limited and well-distributed damage. To do this analysis a non-linear static analysis called pushover analysis had conducted on the structure. In this paper, an RC building with both 5 storey and 10 storey is designed for both gravity loads and earthquake resistant loads using SAP2000 software. Analysis is done in both X and Y direction to get a damage curve (pushover curve). By studying the damage curve, the results that obtained are earthquake resistant designed building had more strength when compared to gravity load designed building and it is better to consider earthquake in building design , because gravity loads alone cannot give the adequate results.
Effect of joint rigidity on structural behavior of RC buildings
Authors: Spandana Kurelly , Raju Y. Kamala , Satyanarayana G V V , Manchalwar Atulkumar
Published: October 2021

Non-linear static analysis or pushover analysis is now-a –days generally preferred by many researchers to analyse the non-linear behaviour of the structure. Present study includes the effect of joint rigidity on the behaviour of the structure. A building is modeled with 5 and 10 story and designed for gravity and earthquake resistant loads by considering joint rigidity factor as 0 and 1. The analysis is done in both X and Y directions by using pushover analysis in SAP2000 software. Comparison is made between then capacity curves obtained from designed models of rigidity and non-rigidity models. From the results it is concluded that structure designed using joint rigidity has more strength when compared non-rigid joints.
Impedance based service life assessment of corroded structures with Cross correlation analysis
Authors: Pravallika N. Naga Sai , Mallikarjuna Reddy V. , Konda Reddy B. Siva
Published: October 2021

Electro mechanical impedance technique has garnered major significance in structural health monitoring field by integrating with information and sensing technology. Technical advancements in automated smart devices improved the diagnostic evaluation of this monitoring method by incorporating piezoelectric materials. The optimistic coupling property of these materials enhanced the life span of structural members by detecting damages at incipient stage. The intervention of piezoelectric transducers has created potential applications for impedance approach in assessing the structural performance with high feasibility. The present work aims at estimating the service life of simply supported smart beam using piezoelectric sensors in Abaqus Simulia software. Corrosion is deployed at a uniform rate in reinforced concrete beam with impressed current flow and the loss in diameter of rebar is calculated using Faraday’s electrochemical equation. With frequency domain based impedance technique numerical analysis is conducted on the modeled beams by exciting the sensor with an external harmonic force and the output electric responses of different piezoelectric locations are captured. The steady state dynamic responses for different cases are compared and quantified with a statistical damage algorithm in MATLAB. The resulted cross correlation indices are analyzed to prevent further deterioration of the corroded beams by setting a limit value. The proposed simulation technology is capable of estimating the residual life span of damage structures with cross correlation analysis.
Flexible pavement design of district road
Authors: VenkatCharyulu S. , Viswanadh G.K.
Published: October 2021

In nowadays it is very important to have a proper road network for the purpose of good transportation. Few places road network is not available while the traffic is higher and enough. Pavement is generally being constructed and used for the purpose of smooth and comfort moment of the traffic. Flexible pavements will be subjected to load by wheel develop stress particles-to-particles transmit to the lower grades of layers through the granular structure. The pavement is subjected to the wheel loading action on it and the load is to be distributed to a larger area, such that the decrease in stress will occur with respect to the depth. The patch considered in this project is of KKY District Road. [KKY-Karimnagar Kamareddy Yellareddy]. The current condition of the KKY road is very much disturbed with the presence of uneven undulations as heavy loaded vehicles like moment of trucks took part. Hence, for the purpose of the fulfilment of all the above requirement factors and for the comfort moment of traffic. Adopted the effective design of flexible pavement. In this paper, we are enclosing the design report KKY road which includes all the which comes under the project of the pavement construction.
Deformation behavior of Austenitic stainless steel at subzero temperature
Authors: Krishnamraju M. , Kumar Abhishek , Mishra Sushil , Narasimhan K
Published: October 2021

Austenitic stainless steel is one of the second generation advanced high strength steel which finds application in automobile, aerospace and cryogenic components. The component made of austenitic steel might operate in subzero temperature condition because of its excellent formability even at subzero temperature. In the present work several tensile tests were performed on austenitic stainless-steel sheet of thickness 1.2 mm at 0°C, -40°C, -80°C, -120°C and at different strain rates of 0.01/sec,0.001/sec,0.0001/sec. The resultant mechanical properties, like yield strength, tensile strength, elongation percent and strain hardening exponent, along with phase fractions and microstructural properties were analyzed to understand the reasons for change in mechanical properties, on comparing with room temperature properties. It was noticed that tensile strength is 635 Mpa, & strain hardening exponent is 0.38 at room temperature (25 °C) and tensile strength is 1236 Mpa, & strain hardening exponent is O.49 at -120°C. Similarly, XRD characterization revealed that strain induced martensite increased from zero percent at 25°C (room temperature) to 57 percent at-120°C Similarly EBSD characterization revealed that grain average misorientation which also increased from room temperature to-120°C.
Material Evolution of Heat-Treated Aluminum Alloy 6101 Quenched in Different Media
Authors: Ikumapayi O. M. , Akinlabi E. T. , Agwu G. O. , Akande S. , Uchegbu I. D. , Fatoba S. O. , Akinlabi S. A.
Published: October 2021

The goal of this study was to investigate the changing characteristics of Heat-Treated Aluminum Alloy 6101 quenched in various media. The research methodology of this research includes performing heat treatment on the Aluminum Alloy 6101 samples at various temperatures, specifically 250℃, 350℃ and 450℃ as well as carrying out quenching processes of the samples using Brine and Water as the main quenchants, and then allowing some samples to cool in the furnace and the rest to be normalized in air, after which mechanical tests (hardness and impact test) will then be carried out on the samples, followed by the microstructural analysis of the alloy. The study concluded that Aluminum Alloy 6101 should be heated to 250°C to achieve the greatest positive effect on its hardness properties, and the air was found to be the best cooling medium. It was also established that Brine Solution used as a quenching media has no significant effect on the hardness property of Aluminum Alloy 6101. Furthermore, the findings revealed that 350°C is the best temperature for increasing the Impact Absorbed Energy (IE) and Impact Strength (IS) of Aluminum Alloy 6101, and that cooling in the furnace also increases the IE and IS.
Comparative study of Dual-Phase -590 steel on formability at superplastic region and room temperature
Authors: Seshacharyulu K , Singh Swadesh Kumar , Naik B Balu
Published: October 2021

A steel alloy DP590 is commonly used for automobile applications because of its outstanding mechanical characteristics. One crucial limitation of this steel forming is that it has limited malleability and ductility. In this study, we compared the experimental forming limit diagram (FLD) for DP590 at RT and 800°C using stretching. An experiment with a strain rate of 0.01/s is carried out with samples cut in four different directions (0°,30°,60°& 90°) as seen from the rolling direction. Rolling direction specimens have been found to be among the stronger samples. FLD can be applied as a method for studying temperature differences in formability characteristics of DP590. Scanning electron microscopy was used for the analysis deformation pattern. Based on these results, it shows that the material has become significantly more formable.
Characteristic Study on Sisal Fibre Hybrid Composites Filled With Nano SiO2 and Marble Dust Particles
Authors: Sahu Himansu Sekhar , Kar Sasmita , Bhoi Sandeep
Published: October 2021

The synthetic fibres are having high stiffness and strength still high manufacturing cost with environmental issues limited the use of synthetic fibres. This encourages towards thinking of intense research of natural fibres having similar property as synthetic fibres. To obtain the better mechanical and thermal property, hybridization of fibres is mostly preferred and that leads to minimize the use of synthetic fibres. As natural fibres are strong and having more ductile property, though moisture absorption is the primary limitation. So fibres is subjected to various treatments such as physical, thermal, chemical and laser treatments etc., to improve the surface characteristics with better interfacial bonding. Nano particle addition also helps in improving the performance of composites and develops cross linking in bonding of matrix and fibre. This research work mostly focuses on hybridization of short mercerized sisal and glass fibre filled with nano silica and marble dust particles, by injection moulding process with polypropylene matrix. It is noticed that among the addition of different fillers, marble dust added composite gave the better result than SiO2 added composite. Incorporation of SiO2 particles as filler material improves the flexural strength and thermal property of the composite.
Traumatismes relationnels précoces et traumatophilie à l’adolescence
Authors: Drieu Didier , Terradas Miguel M. , Roques Marjorie , Rebelo Teresa
Published: October 2021

Cet article discute des origines des troubles des conduites et des vulnérabilités à l’adolescence en mettant en lien ceux-ci avec la prégnance de traumatismes relationnels précoces qui vont interférer dans la construction de la capacité de mentalisation et les processus d’appropriation subjective. À l’adolescence, ces traumas d’origine hétérogène sur un plan psychique, se retrouvent sous la forme de tendances traumatophiliques. Outre la nécessité de considérer l’adolescent dans ses niveaux de fonctionnements ou capacité de mentalisation, les auteurs soulignent l’importance d’un dispositif de soins qui prenne en compte les origines hétérogènes du trauma, c’est-à-dire les conflits internes chez l’adolescent mais aussi les violences intersubjectives, voire transubjectives liées à l’environnement.
Les douleurs chroniques en pédiatrie : qu’en savons-nous ?
Authors: Dugué Sophie , Tourniaire Barbara
Published: October 2021

Lorsque la douleur persiste ou se répète, elle impacte tous les domaines de vie de l’enfant ou de l’adolescent, entraînant des retentissements sur les capacités fonctionnelles et relationnelles de l’enfant que ce soit dans la vie familiale ou sociale. Elle s’accompagne souvent de troubles du sommeil, de troubles anxieux, dépressifs ou de manifestations psychopathologiques induites ou associées pouvant renforcer l’expérience douloureuse. Dans ces situations, mais aussi lorsque la douleur résiste aux traitements habituels, cela renforce le cercle vicieux de la douleur chronique. Alors une évaluation globale de la situation, selon le modèle biopsychosocial est indispensable, afin de proposer un projet thérapeutique personnalisé et adapté. Lorsque les impacts de cette douleur qui persiste, se répète ou résiste aux traitements, sont trop importants, l’enfant doit être adressé en consultation dans une Structure Douleur Chronique (SDC) pour bénéficier d’une prise en charge par une équipe multiprofessionnelle et multidisciplinaire qui sera en lien avec les professionnels de santé de proximité (médecin ou pédiatre traitant, psychologue, kinésithérapeute, médecine scolaire...). Après une synthèse des principales caractéristiques disponibles dans la littérature concernant les douleurs chroniques de l’enfant, nous verrons comment s’est développée depuis les années 1990 la prise en charge des douleurs chroniques de l’enfant en France et comment s’organise le parcours de soin à l’heure actuelle.
L’expérience d’un centre de la douleur chronique de l’enfant et de l’adolescent
Authors: Tourniaire Barbara
Published: October 2021

La douleur chronique de l’enfant est une expérience sensorielle et émotionnelle complexe intriquée avec des éléments individuels et familiaux, des événements de vie, la rencontre bien souvent d’un événement somatique et d’une histoire de vie. Les recommandations en tiennent compte, prônant le modèle biopsychosocial pour les consultations et centres de la douleur. Mais comment faire en pratique ? Comment organiser et dérouler la consultation, comment évoquer les éléments émotionnels tout en tenant compte des éléments cliniques et plus somatiques du dossier ? Comment proposer un projet de soin individualisé ? Cet article décrit l’expérience et le dispositif du Centre de la douleur de l’enfant d’un hôpital pédiatrique, l’art médical et la façon de croiser les regards en équipe médicale et psychologique sur les situations complexes. Il expose un modèle de fonctionnement d’équipe, de consultations fréquentes en binôme médecin-psychologue, reliant ainsi des domaines souvent distingués dans la médecine actuelle, mais qui doivent être remis en commun pour aborder les douleurs chroniques. Il évoque les projets de soins possibles et les articulations avec l’entourage professionnel et personnel de l’enfant douloureux.
Applied aspects of investments in innovation in Bulgarian companies
Authors: Blagoev Dimitar
Published: October 2021

Investment and innovation have traditionally been seen as interconnected areas of activity. Clarifying this relationship in the business practice of Bulgarian companies is an interesting task, from a scientific and applied point of view. The intensity of innovation resulting from the dynamics of the global economy also implies pressure on companies to make more and more investments in new products, new technologies, new working methods and managements, etc. At the same time, not all innovative technologies and/or products are characterized by the necessary cost-effectiveness. This requires companies to apply appropriate methods for assessing the profitability of investments in innovation, as well as methods for assessing the risk of such investments. The purpose of this article is to investigate the practice of Bulgarian companies (based on a limited range of researched but completely randomly distributed) in applying approaches and methods for assessing the effectiveness of investments in innovation. To achieve the main objective, methods such as: literary review, observation, survey, two-dimensional statistical distribution, analysis and synthesis of primary information, comparative analysis, expert evaluation, etc. are used. In conclusion, some summaries of good practices and recommendations for increasing the effectiveness of these processes in the practice of companies are given.
Zink und Diabetes mellitus
Authors: Claßen Hans-Georg , Reich Anna
Published: October 2021

Zink spielt beim Diabetes mellitus eine wichtige Rolle, da das Spurenelement die Insulinbildung, -wirkung und -resistenz beeinflusst. Diabetiker*innen sind für die Ausbildung von Zinkmangelzuständen prädisponiert. Eine hohe Phytataufnahme mit Vollkornprodukten und Hülsenfrüchten vermindert die Bioverfügbarkeit von Zink. Die prophylaktische Zinksupplementation zeigt Studien zufolge positive Effekte bei Prodiabetes und Gestationsdiabetes. Für Erwachsene gilt ein oberer sicherer Dosenbereich (UL) von 25 mg Zink/d in Supplementen.
Magnesiumstatus bei älteren Hypertonikern – Bedeutung des ionisierten Magnesiums
Authors: Kisters Klaus , Kisters Sophia , Gröber Uwe
Published: October 2021

Magnesium ist an ca. 600 enzymatischen Reaktionen und Stoffwechselprozessen beteiligt. Ein Mangel beeinträchtigt die Energieproduktion mit Auswirkungen auf Organfunktionen sowie die Reaktion des Körpers auf Stress. Magnesium hat sich bewährt in der Therapie und Prävention insbes. von kardiovaskulären Erkrankungen wie Hypertonie. In einer Studie an 45 älteren Hypertoniker*innen konnte gezeigt werden, dass die Bestimmung der ionisierten Magnesiumkonzentrationen als Laborparameter aussagekräftiger ist als die herkömmliche Messung der Konzentration im Serum. Magnesiummangel betrifft bes. häufig ältere Menschen und Hypertoniker. Ein Mangel an Vitamin D verschlechtert den Magnesiumstatus. Bei Hypertonie wird die orale Supplementierung von 300–500 mg Mg/d empfohlen.
Diabetische Angiopathien
Authors: Gröber Uwe
Published: October 2021

In Europa ist Deutschland das Land mit der höchsten Prävalenz für Diabetes mellitus mit stark zunehmender Tendenz. Der überwiegende Teil der Patienten ist am Typ-2-Diabetes erkrankt. Die diabetisch bedingten Mikro- und Makroangiopathien können zu einer Reihe Spätfolgen wie Gefäß-, Nerven- und Organschäden führen. Sie beruhen auf Induktion prooxidativer und entzündlicher Prozesse, die insb. auf eine mitochondriale Mehrproduktion von Superoxidradikalen (-O2
•) und anderen reaktiven Sauerstoffspezies (ROS) zurückzuführen sind. Die Kompensation von Mikronährstoffmängeln und eine frühzeitige Supplementierung mit Mikronährstoffen ist eine vielversprechende Therapieoption.
Diagnosis and Management of Status Epilepticus
Authors: Al-Faraj Abrar O. , Abdennadher Myriam , Pang Trudy D.
Published: October 2021

Seizures are among the most common neurological presentations to the emergency room. They present on a spectrum of severity from isolated new-onset seizures to acute repetitive seizures and, in severe cases, status epilepticus. The latter is the most serious, as it is associated with high morbidity and mortality. Prompt recognition and treatment of both seizure activity and associated acute systemic complications are essential to improve the overall outcome of these patients. The purpose of this review is to provide the current viewpoint on the diagnostic evaluation and pharmacological management of patients presenting with status epilepticus, and the common associated systemic complications.
Acute Neurologic Manifestations of Systemic Immune-Mediated Diseases
Authors: Galetta Kristin , Bhattacharyya Shamik
Published: October 2021

Systemic autoimmune diseases can affect the peripheral and central nervous system. In this review, we outline the common inpatient consultations for patients with neurological symptoms from rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus, sarcoidosis, immunoglobulin G4–related disease, Behçet's disease, giant cell arteritis, granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis, polyarteritis nodosa, and ankylosing spondylitis. We discuss the symptoms, diagnostic strategies, and treatment options.
Radiation Segmentectomy
Authors: Prachanronarong Kristina , Kim Edward
Published: October 2021

Radiation segmentectomy is an yttrium-90 transarterial radioembolization treatment where a high radiation dose is administered to a small volume of liver to achieve a high tumoricidal dose to a target with anatomic surgical precision while sparing surrounding parenchyma. This therapeutic modality is often used to treat hepatocellular carcinoma, and recent studies have demonstrated that radiation segmentectomy is an effective treatment as a neoadjuvant to transplant, resection, or as a standalone treatment. This article provides a review of radiation segmentectomy, indications for treatment, recent outcome data, and guidelines for postprocedural management.
Post Yttrium-90 Imaging
Authors: Rice Mitchell , Krosin Matthew , Haste Paul
Published: October 2021

Transarterial radioembolization with yttrium-90 (90Y) is a mainstay for the treatment of liver cancer. Imaging the distribution following delivery is a concept that dates back to the 1960s. As β particles are created during 90Y decay, bremsstrahlung radiation is created as the particles interact with tissues, allowing for imaging with a gamma camera. Inherent qualities of bremsstrahlung radiation make its imaging difficult. SPECT and SPECT/CT can be used but suffer from limitations related to low signal-to-noise bremsstrahlung radiation. However, with optimized imaging protocols, clinically adequate images can still be obtained. A finite but detectable number of positrons are also emitted during 90Y decay, and many studies have demonstrated the ability of commercial PET/CT and PET/MR scanners to image these positrons to understand 90Y distribution and help quantify dose. PET imaging has been proven to be superior to SPECT for quantitative imaging, and therefore will play an important role going forward as we try and better understand dose/response and dose/toxicity relationships to optimize personalized dosimetry. The availability of PET imaging will likely remain the biggest barrier to its use in routine post-90Y imaging; thus, SPECT/CT imaging with optimized protocols should be sufficient for most posttherapy subjective imaging.
Principles of Radioembolization
Authors: Sivananthan Gajan , Tabori Nora E.
Published: October 2021

Radioembolization has become a mainstay therapy in the treatment of primary and secondary liver cancers. This article will specifically discuss a brief history of yttrium treatment as well as an overview of the physical properties of the currently available devices. A discussion of the mechanism of action will be followed by a discussion on patient selection for this treatment.
First Computed Tomography Evidence of Pulmonary Cavitated Lipoma: Diagnosis and Management
Authors: Valente Tullio , Bocchini Giorgio , Rea Gaetano , Paccone Marianna , Vitale Giuseppe , Sica Giacomo
Published: October 2021

Lipomas are the most common form of benign soft tissue tumors in humans, occurring infrequently in visceral organs. Pulmonary lipomas are seen rarely and can occur such as an endobronchial (80%) or peripheral parenchymal (20%) lesion. Less than 10 cases of lung peripheral lipoma are described in literature, none cavitated. We report the clinical case of a 51-year-old emphysematous smoker man with a peripheral intrapulmonary middle-lobe cavitating lipoma, revealed during a routine chest X-ray for emphysema, subsequently confirmed by high-resolution computed tomography (HRCT) and positron emission tomography (PET)–CT. Some hypotheses are made about the origin of cavitation. Biopsy and surgery were not done due to the fully benign nodular features at imaging. The nodule was unchanged till 2 years, last follow-up with low-dose HRCT. It is probably useful to choose a conservative approach with a follow-up, if there is a high suspicion of benignity.
Postpartum Reversible Cerebral Vasoconstriction Syndrome Presenting with Radiological Plethora
Authors: Sharma Manisha , Menon Bindu , Manam Gayatri
Published: October 2021

Reversible cerebral vasoconstriction syndrome (RCVS) is a clinicoradiological syndrome characterized by segmental vasoconstriction of cerebral arteries with resolution in most patients within 1 to 3 months. It has been known to be a benign uniphasic reversible illness but cases of fulminant RCVS with mortality have also been reported. The symptoms can be varied with presentations like transient ischemic attack (TIA), ischemic stroke (IS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and posterior reversible encephalopathy syndrome (PRES). We report a postpartum female with RCVS with radiological features of ICH, SAH, atypical PRES, and atypical clinical presentation as well. RCVS can be frequently missed unless there is a high index of suspicion. Hence clinicians should be aware of the typical and the atypical presentation of RCVS along with the radiological findings with the potential complications. Early suspicion and detection in the emergency help in recovery and reducing morbidity.
On- and Off-Farm Diversification and Travel Time to Markets: Linkages to Food Security in Rural Ethiopia
Authors: Bergau Sven , Loos Tim K. , Sariyev Orkhan
Published: October 2021

Food insecurity persists in large parts of Ethiopia. Recent literature suggests that both on-farm and off-farm diversification, as well as access to agricultural markets, may help improve household dietary diversity scores (HDDS) as an indicator for food and nutrition security. While the HDDS is frequently used, a diversity score for the production side has rarely been applied at a comparable level of (dis-)aggregation. Employing socio-economic data collected covering 400 Ethiopian smallholder farmers, this study investigates how the travel time to markets, non-farm income, and on-farm production diversity associate with household food and nutrition security. Findings suggest that production diversity and higher non-farm income are linked to more diverse diets. With longer travel time to markets, food consumption is less varied. Production diversity and increased market participation do not appear to be mutually exclusive, and thus, should be considered equally when developing policy interventions.
Growth rates of modern science: a latent piecewise growth curve approach to model publication numbers from established and new literature databases
Authors: Bornmann Lutz , Haunschild Robin , Mutz Rüdiger
Published: October 2021

Growth of science is a prevalent issue in science of science studies. In recent years, two new bibliographic databases have been introduced, which can be used to study growth processes in science from centuries back: Dimensions from Digital Science and Microsoft Academic. In this study, we used publication data from these new databases and added publication data from two established databases (Web of Science from Clarivate Analytics and Scopus from Elsevier) to investigate scientific growth processes from the beginning of the modern science system until today. We estimated regression models that included simultaneously the publication counts from the four databases. The results of the unrestricted growth of science calculations show that the overall growth rate amounts to 4.10% with a doubling time of 17.3 years. As the comparison of various segmented regression models in the current study revealed, models with four or five segments fit the publication data best. We demonstrated that these segments with different growth rates can be interpreted very well, since they are related to either phases of economic (e.g., industrialization) and/or political developments (e.g., Second World War). In this study, we additionally analyzed scientific growth in two broad fields (Physical and Technical Sciences as well as Life Sciences) and the relationship of scientific and economic growth in UK. The comparison between the two fields revealed only slight differences. The comparison of the British economic and scientific growth rates showed that the economic growth rate is slightly lower than the scientific growth rate.
Perceptions of risk for COVID-19 among individuals with chronic diseases and stakeholders in Central Appalachia
Authors: Ahuja Manik , Mamudu Hadii M. , Weierbach Florence M. , Dowling-McClay Karilynn , Stewart David W. , Awasthi Manul , Paul Timir K.
Published: October 2021

Coronavirus disease 2019 (COVID-19) pandemic is rapidly evolving and is a serious public health threat worldwide. Timely and effective control of the pandemic is highly dependent on preventive approaches. Perception of risk is a major determinant of health behavior. The current study explores the association between actual risk and perceived risk for one’s self, family/friends and friends, and community. A questionnaire was administered to participants in Central Appalachia (n = 102). The actual risk was based on the number of chronic conditions of the following conditions: hypertension, heart disease, cancer, diabetes, and chronic obstructive pulmonary disease. Participants were also queried about their perception of risk for COVID-19. Generalized Linear Models were used to independently evaluate the likelihood of perceived risk for one’s: self, family/friends, and community, based on actual risk. Actual risk for COVID-19 was significantly associated with higher likelihood of higher perception of risk for one’s self (b = 0.24; p = 0.04), but not with one’s family/friends (b = 0.05; p = 0.68), or one’s community (b = 0.14; p = 0.16). No health insurance was negatively associated with perception of risk for self (b = −0.59; p = 0.04) and family/friends (b = −0.92; p < 0.001). Male gender (b = −0.47; p = 0.01) was also negatively associated with perception of risk for family/friends. In conclusion, individuals’ actual risk for COVID-19 is associated with their own perception of risk. This indicates that one’s perception of risk for COVID-19 is greater for their own health compared to their family/friends or the community. Therefore, monitoring and following up with chronic disease patients and addressing their lack of awareness of risk to others is needed to prevent and curtail the spread of COVID-19.
Generator produces electric arcs accurately and efficiently mimicking lightning in nature
Authors: Liebendorfer Adam
Published: October 2021

The direct current-direct current converter looks to provide new methods for generating experimental data for the aviation industry and other areas prone to lightning strikes.
Lattice-dynamics-based descriptors for interfacial heat transfer across two-dimensional carbon-based nanostructures
Authors: Hatam-Lee S. Milad , Gordiz Kiarash , Rajabpour Ali
Published: October 2021

Graphene and several other two-dimensional (2D) carbon-based structures, including C3N, C3B, C2N, C3N4 (s-triazine), and C3N4 (tri-triazine), have attracted considerable attention due to their excellent thermal, mechanical, and electrical properties. In this study, the correlations between the interfacial thermal conductance (ITC) across these 2D nanostructures and the lattice-dynamical properties of the system, including (i) the phonon density of state (DOS) overlap between the sides of the interface and (ii) the percentage of different classes of vibrational modes for each heterostructure, are investigated. The results show that the percentage of localized interfacial modes is a strong descriptor for predicting ITC—even more effective than the widely accepted phonon DOS overlap. Moreover, the ITC between all combinations of these six carbon-based materials, its dependence on the length of the heterostructure, and the thermal rectification effect present in each interface structure is studied using non-equilibrium molecular dynamics simulations. The results show that the maximum and minimum ITC for infinite length systems belong to graphene/C3N and C2N/C3N4 (tri-triazine) heterostructures with values of 35.81 and 2.21 GW m−2 K−1, respectively. Comparing the thermal resistances at the interface and in the bulk of these heterostructures show that thermal transport in carbon-based 2D materials is influenced by the thermal resistance across their interfaces. These results not only contribute to our fundamental understanding of interfacial heat transfer, but can also serve as the basis for the design of nanoelectronic devices based on 2D materials, where the device level performance will indeed be influenced by interfacial phenomena.
The conformal Einstein field equations and the local extension of future null infinity
Authors: Zhao Peng , Hilditch David , Valiente Kroon Juan A.
Published: October 2021

We make use of an improved existence result for the characteristic initial value problem for the conformal Einstein equations to show that given initial data on two null hypersurfaces N⋆ and N⋆′ such that the conformal factor (but not its gradient) vanishes on a section of N⋆, one recovers a portion of null infinity. This result combined with the theory of the hyperboloidal initial value problem for the conformal Einstein field equations allows us to show the semi-global stability of the Minkowski spacetime from characteristic initial data.
Local approaches for electric dipole moments in periodic systems and their application to real-time time-dependent density functional theory
Authors: Schreder Lukas , Luber Sandra
Published: October 2021

Within periodic boundary conditions, the traditional quantum mechanical position operator is ill-defined, necessitating the use of alternative methods, most commonly the Berry phase formulation in the modern theory of polarization. Since any information about local properties is lost in this change of framework, the Berry phase formulation can only determine the total electric polarization of a system. Previous approaches toward recovering local electric dipole moments have been based on applying the conventional dipole moment operator to the centers of maximally localized Wannier functions (MLWFs). Recently, another approach to local electric dipole moments has been demonstrated in the field of subsystem density functional theory (DFT) embedding. We demonstrate in this work that this approach, aside from its use in ground state DFT-based molecular dynamics, can also be applied to obtain electric dipole moments during real-time propagated time-dependent DFT (RT-TDDFT). Moreover, we present an analogous approach to obtain local electric dipole moments from MLWFs, which enables subsystem analysis in cases where DFT embedding is not applicable. The techniques were implemented in the quantum chemistry software CP2K for the mixed Gaussian and plane wave method and applied to cis-diimide and water in the gas phase, cis-diimide in aqueous solution, and a liquid mixture of dimethyl carbonate and ethylene carbonate to obtain absorption and infrared spectra decomposed into localized subsystem contributions.
CSPEC: The cold chopper spectrometer of the ESS, a detailed overview prior to commissioning
Authors: Deen P. P. , Longeville S. , Lohstroh W. , Moreira F. , Fabrèges G. , Loaiza L. , Noferini D.
Published: October 2021

CSPEC is the cold chopper spectrometer of the European Spallation Source (ESS) and will come online with the ESS beam on the target. CSPEC will be the first cold chopper spectrometer on a long pulsed spallation source, which provides great opportunities in terms of signal to noise and novel measuring schemes. We provide a detailed overview of the instrument, scientific design considerations, and engineering requirements.
Quantum clock synchronization over 20-km multiple segmented fibers with frequency-correlated photon pairs and HOM interference
Authors: Liu Yuting , Quan Runai , Xiang Xiao , Hong Huibo , Cao Mingtao , Liu Tao , Dong Ruifang , Zhang Shougang
Published: October 2021

The quantum clock synchronization based on frequency-correlated photon pairs and HOM interference has shown femtosecond-level precision and great application prospect in numerous fields depending on high-precision time-frequency signals. Due to the difficulty of achieving stable HOM interference fringe after long-distance fiber transmission, this scheme of synchronization is hampered from long-haul field application. Utilizing segmented fibers instead of a single long-length fiber, we achieved the stable observation of the two-photon interference of the lab-developed broadband frequency-correlated photon pairs after 20 km-long fiber transmission, without employing the auxiliary phase stabilization method. Referenced to this interference fringe, the balance of the two fiber arms is achieved with a long-term stability of 20 fs. The HOM-interference-based synchronization over a 20-km fiber link is thus demonstrated, and a minimum stability of 74 fs has been reached at 48 000 s. This result not only provides a simple way to stabilize the fiber-optic two-photon interferometer for long-distance quantum communication systems but also makes a great stride forward in extending the quantum-interference-based synchronization scheme to the long-haul field applications.
Spanwise organization of upstream traveling waves in transonic buffet
Authors: D'Aguanno A. , Schrijer F. F. J. , van Oudheusden B. W.
Published: October 2021

This experimental study has the objective of providing new insight into the role of upstream traveling waves (UTWs) in the transonic buffet phenomenon, using the background-oriented schlieren (BOS) technique and corroborating the results with particle image velocimetry. The experiments were carried out on the supercritical OAT15A airfoil under transonic conditions, at a Mach number of 0.7, an angle of attack of 3.5°, and a chord-based Reynolds number of 2.6×106. The specific scope of the investigation is the characterization of the spanwise organization of the buffet phenomenon; therefore, the measurements consider a streamwise–spanwise-oriented field of view on the suction side of the airfoil. A particular topic of interest is the propagation and orientation of upstream traveling pressure waves (UTWs) that occur in transonic buffet. The experimental setup used allowed to confirm the two-dimensionality of the velocity field and of the shockwave, but revealed that the UTWs propagate at a non-zero orientation. Processing of the BOS images with two different procedures (normal and differential), has furthermore allowed to extract the frequency and propagation velocity of the UTWs, which have been confirmed to behave as acoustic waves, traveling at the speed of sound relative to the flow. A further analysis has given hints that the strength of the UTWs is modulated during the buffet cycle and, therefore, in support of the feedback-mechanism description of transonic buffet.
Coherent structures in a compressible turbulent plane jet
Authors: Liu Qilin , Lai Huanxin
Published: October 2021

Coherent structures represented by proper orthogonal decomposition (POD) modes from large-eddy simulation of a compressible plane jet are analyzed. The leading POD modes of the fluctuating velocity components u′, v′, and w′, and the pressure fluctuation p′ are considered. Spatial and temporal features of these modes are analyzed by the modes and the spectra of the temporal coefficients, respectively. Interactions between leading modes of u′, v′, and w′ and the relationship between the modes of u′, v′, and w′ and of the p′ are discussed. The results show that the leading mode of u′ is in the shape of longitudinal stripes, and the mode is dominated by the jet column frequency Stc. For spanwise fluctuation w′, the leading modes are a pair of modes in the shape of a train of ridges along streamwise, and they are dominated by the fundamental frequency St0. The leading modes for v′ are a pair of modes in a row of ribs. For the dominant frequencies of the v′ modes, suppression of subharmonic frequency at St0/2 and formation of sideband frequencies around (St0 ± Stc)/2 are observed. These spatiotemporal features suggest the mode of v′ is modulated by the modes of u′ and w′. Both the leading modes of p′ and of v′ are in the shape of puffs outside the averaged shear layer. These puff modes are related as an oscillation system, which is confirmed by the spectral-POD modes.
Influence of thermal properties on hydrothermal waves in evaporating sessile droplets
Authors: Zhu Ji-Long , Feng Lin , Shi Wan-Yuan
Published: October 2021

The thermal properties of droplets have a significant effect on the evaporation of sessile droplets. In this study, the influence of nondimensional thermal properties on Marangoni instabilities, especially hydrothermal waves (HTWs), in a sessile droplet evaporating at a constant contact angle mode, is numerically investigated using a nondimensional mathematical model. The model considers the transient deformation of the droplet surface during evaporation in a wide range of Marangoni numbers from 1000 to 40 000, evaporative cooling numbers from 1 to 300, relative heat conductivities from 0.01 to 1000, and Prandtl numbers from 0.01 to 25.0. Included are the different kinds of fluids applied in previous works on Marangoni convection in evaporating sessile droplets. The substrate material varies from a vacuum insulation panel with a heat conductivity of 0.002 W/m·K to silver with 429 W/m·K. The results reveal that a sufficiently large Marangoni number, evaporative cooling number, and relative heat conductivity favor the appearance of HTWs, whereas a large Prandtl number inhibits the appearance of HTWs. The mixture mode of Bénard–Marangoni cells and longitudinal rolls or of longitudinal rolls and HTWs can occur for a small relative heat conductivity. The influence of these thermal properties on the characteristics and dynamic behaviors of HTWs are analyzed and the critical Marangoni numbers for the appearance of HTWs are determined. This work can be helpful for understanding the influence of thermal properties on HTWs in sessile droplets.
Propulsive efficiency and efficacy of a pumping sail
Authors: Zhou Peng , Zhong Siyang , Jiang Hanbo , Zhang Xin , So Raymond Chi-Hung
Published: October 2021

This study presents a framework to analyze the propulsive performance of a sail under oscillatory pumping motion, which should be modified from the analysis framework for conventional flapping wings. A new set of metrics, including the propulsive efficiency ηs and efficacy ΔCx¯, which depend not only on the aerodynamic coefficient but also on kinematic conditions of the sailing vehicle, are proposed to characterize the propulsive performance of sail pumping. The necessity of the proposed metrics is illustrated by studying the propulsive performance of a two-dimensional airfoil under different heaving and kinematic conditions through computational fluid dynamic simulations. It was found that the sail pumping typically improves the propulsive performance by lift enhancement instead of drag reduction. Thus, the formation of leading-edge vortices may not be detrimental to the propulsive efficiency of a pumping sail, contrary to that for flapping wings. A propulsive efficiency greater than unity is achievable under certain sailing conditions because a sailing vehicle can extract energy from the wind.