bluuebunny/crossref_metadata_2025 huggingface dataset:
Review on the modeling of the laser sintering process for Polyamide 12
Authors: YAAGOUBI Hanane , ABOUCHADI Hamid , TAHA JANAN Mourad
Published: February 2021

One of the most promising additive manufacturing techniques is selective laser sintering (SLS) of thermoplastic materials. However, the materials successfully applicable to laser sintering (LS) are very limited today. In this study the exceptional position of polyamide 12 powders is underlined. Several numerical and experimental studies have been carried out to make comparisons between the use of powdered materials for polyamide 12 and other types of polymers during the SLS process. The complexity of this process and the interaction between the different phenomena involved has not been fully understood. In this work we highlight the different models of the selective laser sintering of polyamide 12 as well as their different results in order to better understand the functioning of this process.
The effect of straight chimney temperature on pollutant dispersion
Authors: Zair Fida , Mouqallid Mhamed , Chatri El houssine
Published: February 2021

Air pollution is considered one of the most important contemporary problems that threaten a person's life and environment. Among the major sources of air pollution are pollutants emitted from smokestacks. The objective of this work is to numerically study the dispersion of a pollutant ejected from a chimney into an air stream. The mass, momentum and energy conservation equations are solved using the finite volume method (MFV) and numerical simulations are performed using Ansys Fluent CFD software. Two case studies were discussed: The first case study is to study the influence of the direction of the wind speed and in the last case study, the temperature evolution on the dispersion of the ejected plume particles. The study demonstrated the extent of the dispersion in relation to these two parameters. The results obtained confirm the need to improve filtering systems in order to reduce the risks attributed to discharges and to propose solutions to manage the effect of these discharges on the environmental population.
Closed-Loop Supply Chain: A bibliometric and visualization analysis
Authors: Saher Liudmyla , Syhyda Liubov , Korobets Olena , Berezianko Tamara
Published: February 2021

Nowadays, enterprises have to be good for society, to take care of the environment, and to achieve profit at the same time. And the closed-loop supply chain helps them being so. However, there is a lack of bibliometric and visualization research in the area of “Closed-Loop Supply Chain”. Thus, this research aims to present a bibliometric overview to define the current state of scientific production regarding “Closed-Loop Supply Chain”. The review of 807 publications from the Scopus database (1995–2020) was conducted. Two combinations of words with the logical operator (“supply chain” AND “reverse logistics”) were used. The “title, abstract, keywords” field of search in the Scopus database was done. The visualization of the results was made using VOSviewer program to graphically map the material. The study used the co-occurrence of keywords and co-authorship (country) analyses. As a result, the most productive authors and journals were defined. The most cited studies were determined. Country clusters and keywords (co-occurrence) clusters were represented. The obtained results of the analysis and graphical presentations are relevant, and they form the basis for a better understanding of the concept of Closed-Loop Supply Chain.
The impact of the macroeconomic stability on the energy-efficiency of the European countries: A bibliometric analysis
Authors: Pimonenko Tetyana , Us Yana , Lyulyova Liliia , Kotenko Natalia
Published: February 2021

This paper deals with macroeconomic stability impact on improving the countries’ energy-efficiency. For that purpose, the authors conducted the bibliometric analysis using the VOSviewer and Scopus tools. The investigation involved 1335 studies focused on economic stability and 1811 studies – on environmental issues. Thus, the obtained results demonstrated the strong links between investigating environmental factors, particularly, energy efficiency, on business performance, economic and macroeconomic stability. Given that, the authors made forecasting energy-efficiency development. In the current research, primary energy consumption was allocated as a basis for forecast the energy-efficiency. The study involves data between 1991 to 2018 from European countries (EU27) taken from the Eurostat database. The methodology of this study was based on ARIMA model. From the results, the authors concluded that the EU energy targets would be gained by 2020. However, the obtained results allow prognosticating increasing the final energy consumption from 2020 to 2029. Based on analysing the EU experience and the forecast findings, the authors allocated the main recommendations to improve the energy-efficiency in Ukraine. The authors noted that current results are considered to be the base for future investigations aimed at the analysis of the macroeconomic stability impact on increasing energy-efficiency level.
Modeling CO2 capture processes by chemical absorption: The case of biogas treatment
Authors: Maakoul Othmane , Beaulanda Ruth , El Omari Hamid , Essabri El Hassane , Abid Aziza
Published: February 2021

Our objective through this work is to purify the biogas produced by a methanisation process in order to be valorized in a cogeneration unit. The studied biogas is mainly composed of methane 60% and carbon dioxide 39%. The treatment will increase the quality of the biogas by decreasing the percentage of CO2, in order to improve the energetic properties of the gas mixture (PCI). Several biogas purification and bio-methane production processes are commercialized. The choice of the technical and economic optimum is strongly linked to the quality and quantity of biogas to be purified, the quality of the desired bio-methane, depends on the type of methanisation, the nature and regularity of the substrate supply, but also on the local conditions of implantation. In this part of our research project, we are interested in the study, dimensioning and modeling of a CO2 capture unit by chemical absorption, constituted by a packed column. The solvent used is the secondary amines in mixture with the primary amines.
Digital Campus – a future former investment in education for a sustainable society
Authors: Moşteanu Narcisa Roxana
Published: February 2021

Intelligent learning and research are happening everywhere, nevertheless, conventional teaching and learning in universities, based on face-to-face or in person approach is still the basic environment. Actual movements in socio-economic life around the world impose e-learning and e-presence. However, moving digital is more than online teaching, is changing the environment. The present research paper aims to demonstrate how a digital campus, with all aspects, can perform a crucial role in enriching the university campus’s structure and culture to ensure the quality assurance of teaching, research and administrative management using actual innovative technologies. Moreover, digital campus changes the perspective of social and physical environment, and the present paper found out that Digital campus provide anytime and anywhere access to university facilities (maintaining the environment clean in the same time), learning, research, and meeting the industry as well.
Understanding the decisional factors affecting consumers’ buying behaviour towards organic food products in Kerala
Authors: Ms Krishna R. , Balasubramanian Dr P.
Published: February 2021

Rising concern for health and environmental issues associated with the rigorous use of chemical fertilizers has necessitated an alternate form of agriculture in Kerala, and that's how organic production came into existence. The organic agricultural production technique is considered to be quite conflicting with conventional production technique where the use of human-made fertilizers like pesticides, weedicides and insecticides are entirely banned. Organic products are perceived to be minimally processed to maintain the integrity of the food without artificial ingredients and preservatives. Therefore right from mid-eighties, consumers, particularly from the developed countries, started switching over towards organically produced food products as they more nutritious, healthy, and nature-friendly. Considering the organic market in Kerala, the state is still at its infant stage with a market share of less than 1%. Hence it is critical to investigate Kerala consumers low consumption level towards environmentally friendly products. The current research intents to explore the factors influencing Kerala consumers’ organic purchase behaviour based on data collected from 200 respondents (100 regular and 100 irregular organic users) using a structured questionnaire. Analysis techniques comprising of correlation and multiple linear regression has been applied for data evaluation. The research findings support the formulated hypothesis and aim at providing necessary guidelines for various stakeholders who are involved in the organic industry.
Using modern technology to protect vineyards from hail amid climate change
Authors: Davitashvili Teimuraz , Samkharadze Inga , Megreladze Lika , Kvatadze Ramaz
Published: February 2021

Over the past two decades, Georgia has faced increasingly heavy rainfall, hail and flooding, which especially devastated Kakheti wine region in Southern Georgia, causing severe damage to hundreds of vineyards. Since 2015, 85 anti-hail missile systems have been installed to protect entire Kakheti region, however, for the effective use of a modern anti-hail system, it became necessary to timely forecast extreme weather events of a regional and local scale. Thus, this article aims to develop timely forecasting of strong convection, dangerous precipitation and hail using modern weather forecasting models and radar technologies in Georgia. For this reasons various combinations of the physics parameterization schemes of the WRF-ARW model, the ARL READY system and the data of the modern meteorological radar Meteor 735CDP10 are used to predict the thermodynamic state of the atmosphere and assess the possible level of development of convective processes. The analysis of the calculated results showed that the variants of the microphysics parametrization schemes of the WRF model lead to significant variability in precipitation forecasts on complex terrain. Meanwhile, the upper-air diagrams of the READY system clearly showed the instability of the atmosphere for the cases discussed. Some results of these calculations are presented and analysed in this paper.
Determination of correction factor of self-absorption for lead-210 in environment samples using spike method
Authors: Al-Tuweity Jawaher , Kamleh Hassan , Al-Masri M. Said , Doubal A.Wael , Mohamed Azougagh , Alibrahmi El Mehdi , Boukhal Hamid , Chakir El Mahjoub
Published: February 2021

In environment radiation measurement, calculation the correction factors are critical, especially for low energy measurement because of self-absorption phenomena. In this work the main purpose is to determination the self-absorption correction factors of lead-210 (210Pb) energy (46.5keV) in various environment samples (7 sediments, 5 soil) using an experimental method called Spike Method. The samples were collecting from different places in Syrian. They were prepared according to the laboratory producers starting from collecting, cleaning, drying, grounding, hemogenic and calculating the appearance density. Low-energy gamma spectroscopy HPGe was used for radiation analysis which available at the laboratories of the Protection and Safety Department - Syrian Atomic Energy Commission – Syria. The spike method depends on adding a quantity of a standard solution with a known activity which contains lead isotope 210Pb and added to the studied samples. Self-absorption correction factors (CF) calculated by the ratio of the count rate or activity of spiked and unspiked samples. The CF for sediment samples were between 29% to 54% and for soil samples, the CFs were between 38% to 56% recording correction higher than sediment samples. The results showed a relatively high self-absorption and CFs values because of the chemical composition changeable between the spiked and unspiked samples. For that, it is better to adopt other methods less expensive, give results faster, higher accuracy and do not make change in the chemical composition. The results were also showed the density factor is the most influential factor in self-absorption phenomena.
Optical properties and effects on direct solar irradiance of aerosols: Asian East case
Authors: Ben-tayeb Abdelmoula , Diouri Mohammed , Tahiri Abdelouahid , Meziane Rajae
Published: February 2021

Atmospheric aerosol is an important factor that affects solar irradiance. In this study, we examined the total atmospheric optical depth, aerosol optical depth AOD and the vertical particle size distribution in East Asia in terms of aerosol type during three years. The temporal variation of the aerosol optical depth for each site showed a constant mode renewed each year, the large AOD0,5 are recorded in spring and summer in an almost periodic manner, with maximums around 0.95 in Seoul, 0.08 in Chiang Mai and 1.34 in EPA-NCU. The particle size distributions under a bimodal lognormal form present a remarkable increase in volume concentration of fine and coarse modes during spring. The aerosols reduce solar irradiance by 37.33 ± 0.78% in Chiang Mai, 33.48 ± 6.43% in EPA-NCU and 38.59 ± 3.86% in Seoul.
Environmental education for the sustainable development of suburban communities in Ho Chi Minh City
Authors: Huynh Tan Hoi
Published: February 2021

Rapid urbanization contributes to a widening gap between the rich and the poor, which also increases the pressure on natural resources and the environment. Many industrial establishments emit uncontrollable hazardous substances and a lot of the waste belongs to the municipalities. Some of municipal waste is discharged into rivers and canals. In Ho Chi Minh City, the issue is not only a pressing issue of the city government but also affects the health of the people and the urban beauty. And as a result, it is currently the most polluting source for the city's canals. This study focuses on the assessment of environmental issues, environmental awareness and its impact on the livelihoods of suburban residents. By carrying out a survey, the research results show that many environmental problems have appeared quite serious and complicated developments. The article proposes some environmental education solutions for sustainable development with the people-focused principle in order to promote the responsibility of the people.
Some solutions for sustainable agricultural tourism development in the Mekong Delta in Vietnam
Authors: Hoang Gia Bao
Published: February 2021

Agricultural tourism is a current trend in the Mekong Delta of Vietnam need to exploit and it is necessary to take advantages of the natural advantages to exploit key trends such as authentic cultural experiences, ecotourism, agricultural tourism, healthcare, etc. In recent years, agricultural tourism products have been the main attraction and these products can promote both domestic and international tourist growth. With many tourism products bearing the cultural characteristics of the region is known, stretching from North to South in general and in the Mekong delta in particular, agro-tourism has brought increasingly clearer socio-economic effects, contributing to the abundance and attractiveness of tourism products, and at the same time improving high levels of income for farmers. This paper focuses on analyzing the advantages as well as disadvantages and from there proposing some solutions for the most practical agricultural tourism in this area.
Indicators of Integrated Water Resources Management at the local level: Meknes as a case (Morocco)
Authors: Ben-Daoud Mohamed , Moumen Aniss , Sayad Ahmaed , ELbouhadioui Mohamed , Essahlaoui Ali , Eljaafari Samir
Published: February 2021

This work aims to develop integrated water resources management (IWRM) and conduct an IWRM implementation assessment based on the study area's indicators. In this way, we have adopted a participatory approach for IWRM indicators development. As for assessing implementation at the local level, a survey was conducted among water sector actors in the study area to collect opinions regarding their management mode. In terms of results, four categories of indicators were developed in consultation with participating stakeholders, and an assessment of IWRM implementation was carried out. This assessment shows that the current management system is generally medium and that there is a difference between stakeholders regarding their capacity to IWRM implement. Some needs were identified for the majority of stakeholders to meet the requirements of integrated water management fully. The final target is to apply the IWRM in Meknes city as a case study that will eventually allow us to evaluate the water management system developed based on these indicators.
Current situation and awareness of pesticide abuse in agriculture in Vietnam
Authors: Nguyen Tan Danh
Published: February 2021

Chemicals such as pesticides, antibiotics and hormones are used for plants and animals to boost production and ensure an adequate supply of food. However, when using these chemicals in excess of the maximum allowable limit in food can cause many unfortunate consequences for human health, from short-term effects such as headaches and nausea to chronic effects such as cancer, damaging organs and causing many diseases. The harms of many pesticides and plant protection to human health and ecosystems in Vietnam are something that scientists, newspapers and many organizations have warned against for many years. Plant protection drugs are toxic to humans and livestock, adversely affect public health, pollute the environment, and kill both insects and beneficial microorganisms, thereby creating conditions for stronger disease development. If using the wrong technique, it will quickly create resistance to the insecticide. Plant protection drugs sometimes leave toxic residues on agricultural products, poisoning users, reducing the quality and competitiveness of agricultural products. The article uses the method of analyzing and comparing data and numbers to determine the impact of pesticides on human life. This paper also focuses on analyzing the use of homestead, the disadvantages, limitations, and negatives of the drugs to life and to raise awareness of drug users.
Assessment of soil erosion using two spatial approaches: RUSLE and SWAT Model
Authors: Taia Soufiane , Erraioui Lamia , Mbrenga Noella Claire , Chao Jamal , El Mansouri Bouabid , Haida Souad , Taj-Eddine Kamal
Published: February 2021

In this paper, we attempted to review the erosion in the Ouergha watershed by applying two spatial approaches. The Ouergha watershed has an area of around 7300 km² representing approximately 18.2% of the Sebou basin of which it is the main tributary. In order to develop the erosion map using the SWAT model, it was important to prepare a large spatial database describing basin proprieties, furthermore, the daily hydro-climatic data. This model integrates MUSLE equation for the estimation of specific degradation. In addition, the estimation of erosion through SWAT was consolidated by constructing an erosion mapping through RUSLE method. This method was applied following an approach based on the use of remote sensing data and GIS tools to produce the major factors involved in the erosive process and their integration into RUSLE. The results obtained, in cartographic form, make it possible to target areas that require priority action for a larger-scale analysis, with a view to finding appropriate solutions to fight against erosion and protect the natural environment. Soil degradation in the Ouergha watershed is around 27 ton/ha/year (SWAT_MUSLE) and 25 ton/ha/year (RUSLE). Average sediment yield was estimated for Al Wahda dam of 10.4 Million tons.
Research on Transfer Characteristics of Engine Vibration Load to Cabin Seat
Authors: Shu Juncheng , He Erming , Yi Jinxiang , Chen Pengxiang
Published: February 2021

Aeroengine is one of the main vibration sources that affect the passenger comfort. The contribution of engine vibration to the vibration response of seat will provide basic data for the design of airliner vibration comfort and engine vibration isolation installation. Firstly, the dynamical model of middle fuselage compartment with double-beam wing was established. Then, based on the typical vibration load spectrum of the engine, the acceleration responses of the key nodes of the wing beam and the seat connection points were analyzed, and the main path of engine vibration transmission to seats was identified. Finally, using operational transfer path analysis (OTPA) method, the contribution of engine front and rear mount point vibration to the vertical acceleration response of the seats was compared, and the three-dimensional information of wing structure vibration transmission was explored. The results show that the fundamental frequency component of low-pressure rotor of engine vibration has the greatest impact on the seat vertical response under takeoff and cruise conditions, the contribution rate of the front mount point vibration is about 71% and 67% respectively. However, the fundamental and its 3/2 times frequency components of high-pressure rotor have relatively large impact on the seats vertical response under flight idle state, and the contribution rate of engine front mount point vibration is about 45% and 60% respectively. In addition, the engine vibration is mainly transmitted from the wing front beam to the seat vertical response. The vertical direction of the wing beam and the rotation direction around the fuselage are also the main direction of vibration transmission.
Effect of Rotating Direction on Flow and Temperature Field of Concentric Staged Combustor
Authors: Li Le , Suo Jianqin , Zheng Longxi
Published: February 2021

The characteristic of cold/reaction flow and temperature field were investigated by using the numerical simulation for concentric staged multi-point direct injection combustor. The interaction mechanism between the flow field and the temperature field was revealed, and the effect rules of the swirlers rotating direction on the flow and temperature field were obtained. The results indicated that the central recirculation zone with divergence angle of 17 degrees is formed under cold condition by using the co-rotating swirlers and counter-rotating swirlers, and the central recirculation zone size of co-rotating swirlers is larger than that of counter-rotating swirlers. Heat release of the flame causes the similar central recirculation zone shape is formed by using the different rotating direction swirlers, and the divergence angle increased to 45 degrees. Tangential velocity contour of different aixal sections are undergone the "circular shape", "diamond shape", "elliptical shape" and "upper-lower symmetrical" structures, which represent the formation of the central recirculation zone, initial development, full development and gradual disappearance respectively. With the decreasing of tangential velocity of the swirling air in the combustor, the axial velocity at center of near outlet and the hot spot temperature at the outlet of combustor increase. Therefore, the co-rotating swirlers combustor has a better outlet temperature distribution factor (OTDF).
Research on Fault Detection Method of FADS System
Authors: Jia Qianlei , Zhang Weiguo , Shi Jingping , Li Guangwen , Liu Xiaoxiong
Published: February 2021

In order to solve the fault detection problem of flush air data sensing (FADS), an advanced airborne sensor, a new method is proposed in this paper. First, the high-precision FADS model is established on the basis of the database obtained from the CFD software and aerodynamics knowledge. Then, the distribution characteristics of each group of signals under fault condition are derived through strict formulas. Meanwhile, the threshold of alarm times is designed with statistical knowledge. For verifying the effectiveness of the newly proposed method, a comparison with other two widely adopted methods, including the methods based on parity equation and Chi-square χ2 distribution, is conducted under different measurement noise. Simulation results show that the proposed fault detection method for FADS possess higher accuracy and stronger anti-interference.
Flight Load Design of Nacelle of Carrier-Based Propeller Transport Aircraft
Authors: Ma Kaichao , Tang Changhong , Zhang Jianye , Niu Xiaofei , Fan Qingzhi
Published: February 2021

The carrier-based propeller transport aircraft has a compact layout, where the large nacelle in size and weight is sensitive to propeller slipstream, and thus calls for sophisticated flight load design studies, which are still insufficient considering domestic experience. In detail, the design methods on aerodynamic load, inertial load, gyrostatic moment, as well as studies on design criteria and maneuver simulation technology are shown for a reference aircraft. The design range applied to this nacelle's flight load is firstly determined by understanding and selecting the design criteria. The typical loadcases of the nacelle are derived from aircraft maneuver simulation. The data of pressure distribution under a series of propeller slipstream strengths is obtained by CFD method. The Design Loads and Design Loadcases of the nacelle are calculated and selected. The effects of the propeller slipstream are compared in an example of the increment on aerodynamic load in a maneuver. The results show that the Design Loads of the nacelle are obtained from the abrupt pitching maneuver under the maximum normal load factor (Nz), the yawing maneuver under the Design Dive Speed(VD), and the maximum propeller pull under the maximum landing weight; the transverse loads of the nacelle are dominated by the aerodynamic load, and the normal loads are dominated by the inertial load, in which the inertial force exceeds the aerodynamic force by 4 times under the extreme circumstances. In some manoeuvres or status, the total aerodynamic force of the whole nacelle is increased by above 90% due to propeller slipstream; the front part of the nacelle which is close to the propeller sees a much bigger increment.
Principle and Method for Machining Face Gear with Developable Ruled Surface
Authors: Peng Xianlong , Hou Yanyan , Zhang Le , Han Feiyan , Kou Farong
Published: February 2021

The tooth surface of a face gear is recognized as un-developable ruled surface in tradition, which result in the problem that face gear generation using simple cutter with high efficiency and accuracy puzzled people for a long time. Applying the traditional shaping method for face gear generation in derivation of the tooth surface position vector, a space straight line equation was established by using this vector, to illustrate that the tooth surface of the traditional face gear could be considered as developable ruled surface constituted by space lines family, the position vectors of the developable ruled surface were established respectively based on involute, rack and considering the spatial position relationship in meshing. Elaboration and proposition of the principle and method that were used to generate the face gear with the developable ruled surface by straight edged cutter in line contact, and representation of the generated surface model. Furthermore the developable ruled surface was compared to the traditional surface, the normal difference between the two kinds of surfaces is on micro-scale. Numerical examples shows that the normal distance is no more than 1/70 of modulus, the developable ruled surface to which was performed simple longitudinal crowning is able to mesh with the involute surface of the pinion correctly, and demonstrates acceptable geometric meshing performance.
Relationship between Axial Width and Flow Characteristics of Pump Chamber in Double Volute Centrifugal Pump
Authors: Dong Wei , He Qingnan , Liang Wuke , Wei Qingxi , Dong Yan , Sun Jian
Published: February 2021

The axial width of pump chamber has a great influence on the flow characteristics of the pump chamber in the centrifugal pump. A single-stage single-suction double volute centrifugal pump with a semi-open impeller was selected as the object. For the 6 different pump chamber axial width, it was concluded that the pump chamber pressure at the different angles (0°, 90°, 180°, 270°) along the radial variation characteristics according to the contrast analysis of the pump cavity pressure field, velocity field distribution. The correlation between the pump chamber pressure and the impeller radius was revealed. The tangential velocity and radial velocity along the axial distribution curves were draw. The results show that when the axial width of pump chamber increases from 23.9 mm to 43.9 mm, the pressure value of the same radial position increases gradually. The radial pressure difference is decreasing. At the same axial width of pump chamber, the pressure mean increases along the radial approximately parabola. The tangential velocity of different angular directions has little difference in axial distribution. The mean of dimensionless tangential velocity in the turbulent core area decreases from 0.32 to 0.19 with the increasing of pump chamber axial width. The radial velocity varies is greatly along the axial direction. There are eddies at the directions of 0ånd 180°, but the mean of radial velocity in the turbulent core area is about 0. This research provides the reference for centrifugal pump hydraulic design, structural design and the accurate calculation of axial force.
Bewertungsgrundlagen von Infektionsschutzmaßnahmen im Rahmen der Pandemie
Authors: von Münster Thomas
Published: February 2021

Die Diskussion über eine effektive Strategie im Umgang mit der COVID-19-Pandemie ist voll entbrannt. In der „Great Barrington Declaration“ wird eine Ausbreitung der Erkrankung in der Bevölkerung zur Schaffung einer Herdenimmunität empfohlen 1. Vulnerable Personen sollen dem Konzept nach durch Isolationsmaßnahmen geschützt werden. Gegner des Konzeptes warnen im „John Snow Memorandum“ vor einer erheblichen Morbidität und Mortalität in der Bevölkerung 2. Die Arbeitsgruppe um Viola Priesemann hat ein Modell entwickelt, um die Effektivität von Eindämmungsmaßnahmen in einem Modell zu überprüfen.
Blauer Eisenhut – Aconitum napellus L.
Authors: Latté Peter Klaus
Published: February 2021

Negativmonographie der Kommission E– In der Phytotherapie spielt Aconitumnapelluswegen möglicherIntoxikationserscheinungen im therapeutischenBereichkeine Rolle mehr.
Psychodynamische Psychotherapie der Depression
Authors: Schauenburg Henning
Published: February 2021

Zur Behandlung der Depression eignet sich die psychodynamische Psychotherapie in gleichem Maße wie die kognitive Verhaltenstherapie. Erstere berücksichtigt in besonderem Maße bestimmte Persönlichkeitsmuster der Patienten. Ziel der Therapie ist die Verbesserung der sozialen Kompetenz und die Entlastung von neurotischer Selbstanforderung bzw. -entwertung. Dabei ist die Balance wichtig zwischen Bindungswunsch und frei gewählter Autonomie.
The Elusive Appearance of Hyperenhancing Solid Serous Cystadenoma of the Pancreas—Radio-Pathological Correlation
Authors: Mohan Supraja Laguduva , Chakkalakkoombil Sunitha Vellathussery , Devaraj Sunil Kumar , Kashyap Ravindar , Ganesh Rajesh Nachiappa
Published: February 2021

Serous cystadenomas account for ~10 to 29% of pancreatic cystic tumors. Solid serous cystadenoma (SSCA) is a rare variant, first described in 1996, with imaging characteristics different from the classical serous cystadenoma of the pancreas and can cause a diagnostic dilemma due to its resemblance to other solid tumors of the pancreas. To the best of our knowledge, only 22 cases of SSCA of pancreas have been reported till date.

A 50-year-old female patient underwent contrast-enhanced computed tomography (CECT) of the abdomen for a hypoechoic lesion detected in the body of the pancreas during ultrasound (US) examination. Due to the hyperenhancement of the well-circumscribed lesion in the arterial phase, a provisional diagnosis of neuroendocrine tumor was considered. Gallium 68-labeled somatostatin-analog (Ga 68-DOTANOC) positron emission tomography CT scan did not show any uptake within the lesion and endoscopic US (EUS)-guided fine-needle aspiration cytology (FNAC) was also inconclusive. She underwent laparotomy and the lesion was enucleated and it was proven to be a serous microcystadenoma on postoperative histopathologic examination.

A diagnosis of SSCA should be considered for solid-appearing pancreatic lesions with characteristic CECT features such as arterial phase hyperenhancement, and immediate washout, along with negative results on DOTANOC scan and EUS-guided FNAC. Malignant transformation of SSCA has not been reported till date, and hence these can be safely followed up, instead of invasive surgery.
A Bony Mallet Thumb with Interposition of the Nail Plate
Authors: Afshar Ahmadreza , Tabrizi Ali , Taleb Hassan
Published: February 2021

Thumb extensor injuries and bony avulsion in the distal phalanx of the thumb are rare compared with other fingers. The most reported complications are infection, nail deformity, joint incongruity, implant failure, recurrent flexion deformity, and residual pain. This report presents a case of 30-year-old man suffering from an injury in the left thumb distal phalanx with a displaced comminuted intra-articular fracture of the distal phalanx of the left thumb. The nail plate was interposed between the dorsal and palmar fragments. The interposition of the nail plate in the bony mallet thumb has not been described before. Surgical treatment and fixation with a 2-mm miniscrew resulted in successful treatment. Clinical suspicion of this complication is of great importance and can affect treatment outcomes.
Biallelic Variants in LAMB1 Causing Hydranencephaly: A Severe Phenotype of a Rare Malformative Encephalopathy
Authors: Sen Kuntal , Kaur Shagun , Stockton David W. , Nyhuis Mary , Roberson Jacquelyn
Published: February 2021

Case Report A 32-year-old female with a history of three prior pregnancy losses presented for genetic testing following an ultrasonography diagnosis of fetal hydranencephaly. Baby was born via C-section and was noted to have a head circumference of 48 cm, in addition to ocular and cardiac anomalies and dysmorphic features. Whole genome sequencing revealed a homozygous variant in LAMB1 gene.

Discussion The pathobiogenesis of hydranencephaly is incompletely understood and is attributed to vascular, infectious, or genetic etiology. Herein we present LAMB1 as a monogenic cause of fetal hydranencephaly which was incompatible with life. Previously, LAMB1-associated phenotype consisted of cobblestone lissencephaly and hydrocephalus, developmental delay, and seizures. Our proband expands the phenotypic spectrum of this malformative encephalopathy.
Clinical Study of Postoperative Bleeding after Tonsillectomy in 497 Cases
Authors: Tanaka Takeshi , Ishii Kenji , Matsumoto Kyoko , Miura Koushirou , Kihara Ayako , Kamio Tomonobu
Published: February 2021

We conducted a retrospective analysis of 497 patients who underwent tonsillectomy at Kamio Memorial Hospital from September 2015 to August 2018. A total of 35 cases (7.0%) developed postoperative bleeding and three cases (0.6%) needed a second operation under general anesthesia to stop the bleeding. Postoperative bleeding most frequently occurred between 24 hours and 6 days after the operation. The incidence of postoperative bleeding was significantly higher in males and in patients aged 20 to 39 years old. The operation time, body mass index, smoking habit, and history of hypertension were not identified as clinical risk factors for bleeding after tonsillectomy in this study.
Vortex-sheet modeling of hydrodynamic instabilities produced by an oblique shock interacting with a perturbed interface in the HED regime
Authors: Pellone S. , Di Stefano C. A. , Rasmus A. M. , Kuranz C. C. , Johnsen E.
Published: February 2021

We consider hydrodynamic instabilities produced by the interaction of an oblique shock with a perturbed material interface under high-energy-density (HED) conditions. During this interaction, a baroclinic torque is generated along the interface due to the misalignment between the density and pressure gradients, thus leading to perturbation growth. Our objective is to understand the competition between the impulsive acceleration due to the normal component of the shock velocity, which drives the Richtmyer–Meshkov instability, and the shear flow across the interface due to the tangential component of the shock velocity, which drives the Kelvin–Helmholtz instability, as well as its relation to perturbation growth. Since the vorticity resulting from the shock-interface interaction is confined to the interface, we describe the perturbation growth using a two-dimensional vortex-sheet model. We demonstrate the ability of the vortex-sheet model to reproduce roll-up dynamics for non-zero Atwood numbers by comparing to past laser-driven HED experiments. We determine the dependence of the interface dynamics on the tilt angle and propose a time scaling for the perturbation growth at early time. Eventually, this scaling will serve as a platform for the design of future experiments. This study is the first attempt to incorporate into a vortex-sheet model the time-dependent interface decompression and the deceleration (as well as the corresponding Rayleigh–Taylor instability) arising from laser turn-off.
On the chaotic and hyper-chaotic dynamics of nanobeams with low shear stiffness
Authors: Yakovleva T. V. , Awrejcewicz J. , Kruzhilin V. S. , Krysko V. A.
Published: February 2021

We construct a mathematical model of non-linear vibration of a beam nanostructure with low shear stiffness subjected to uniformly distributed harmonic transversal load. The following hypotheses are employed: the nanobeams made from transversal isotropic and elastic material obey the Hooke law and are governed by the kinematic third-order approximation (Sheremetev–Pelekh–Reddy model). The von Kármán geometric non-linear relation between deformations and displacements is taken into account. In order to describe the size-dependent coefficients, the modified couple stress theory is employed. The Hamilton functional yields the governing partial differential equations, as well as the initial and boundary conditions. A solution to the dynamical problem is found via the finite difference method of the second order of accuracy, and next via the Runge–Kutta method of orders from two to eight, as well as the Newmark method. Investigations of the non-linear nanobeam vibrations are carried out with a help of signals (time histories), phase portraits, as well as through the Fourier and wavelet-based analyses. The strength of the nanobeam chaotic vibrations is quantified through the Lyapunov exponents computed based on the Sano–Sawada, Kantz, Wolf, and Rosenstein methods. The application of a few numerical methods on each stage of the modeling procedure allowed us to achieve reliable results. In particular, we have detected chaotic and hyper-chaotic vibrations of the studied nanobeam, and our results are authentic, reliable, and accurate.
Fabrication of solid CH-CD multilayer microspheres for inertial confinement fusion
Authors: Liu Meifang , Ai Xing , Liu Yiyang , Chen Qiang , Zhang Shuai , He Zhibing , Huang Yawen , Yin Qiang
Published: February 2021

Deuterated polymer microspheres can be used as a neutron source in conjunction with lasers because thermonuclear fusion neutrons can be produced efficiently by collisions of the resulting energetic deuterium ions. A new type of solid deuterated polymer microsphere with a carbon hydrogen–carbon deuterium (CH-CD) multilayer has been designed for preparing the target for inertial confinement fusion (ICF) experiments. To fabricate these solid CH-CD multilayer microspheres, CH beads are first fabricated by a microfluidic technique, and the CD coating layer is prepared by a plasma polymerization method. Both polystyrene (PS) and poly(α-methylstyrene) (PAMS) are used as the material sources for the CH beads. The effects of the PS and PAMS materials on the quality of the solid CH beads and the resulting CH-CD multilayer polymer microspheres are investigated. The solid PS beads have better sphericity and a smoother surface, but large vacuoles are observed in solid PS-CD multilayer microspheres owing to the presence of residual fluorobenzene in the beads and a glass transition temperature of the solid PS beads that is lower than the temperature of plasma polymerization. Therefore, solid PAMS beads are more suitable as a mandrel for fabricating solid CH-CD multilayer polymer microspheres. Solid CH-CD multilayer microspheres with specified size have been successfully prepared by controlling the droplet size and the CD deposition rate and deposition time. Compared with the design value, the diameter deviation of the inner CH beads and the thickness deviation of the CD layer can be controlled within 20 µm and 2 µm, respectively. Thus, an approach has been developed to fabricate solid CH-CD multilayer microspheres that meet the physical design requirements for ICF.
Theoretical calculation model of torque transmission in permanent-magnet couplers
Authors: Shi Jianwen , Suo Shuangfu , Meng Guoying
Published: February 2021

Permanent-magnet couplers are widely used in various industrial applications due to their high functionality and economy. The magnetic field of the magnetic circuit of a permanent-magnet coupler is divided by the segmentation method, by which the magnetoresistance of each area can be calculated. The magnetic resistance of the magnetic flux and the permanent-magnet coupler characteristics outside the magnetic circuit are obtained using the equivalent magnetic circuit model of permanent-magnet couplers. The working point of the permanent magnet is analyzed, and the skin effect is found to be equivalent to a conductor plate with an increase in its resistivity. According to the principle of electromagnetic induction, the ampere force received by each part is calculated. Finally, the theoretical calculation model of the transmitted torque of the permanent-magnet coupler is obtained, and its accuracy is verified by finite element simulation and experiments. This can significantly guide the design and engineering applications of permanent-magnet couplers.
Mechanism of radio frequency breakdown on metal surfaces in relativistic backward wave oscillator
Authors: Tan Nongchao , Wu Ping , Hua Ye , Sun Jun , Huang Wenhui , Huang Wenhua
Published: February 2021

Radio frequency (RF) breakdown can result in pulse shortening and severely limits the performance of the relativistic backward wave oscillator (RBWO). In this study, segmented slow-wave structure (SWS) rings, which can be observed directly using a scanning electron microscope without any post-processing, are used to study the breakdown in a RBWO. After undergoing high-power microwave experiments, the working surface of the SWS rings was found to exhibit corrugated morphologies at the sub-mm to mm scale, and a large number of craters in the vicinity of the corrugated morphologies and a mass of scattered droplets were visible on the surface. It was deduced that the unusual morphologies resulted from electron bombardment of the working surface. The observed structures and droplets provide new evidence that helps to explain the mechanism for RF breakdown in the RBWO.
Hybrid InP and SiN integration of an octave-spanning frequency comb
Authors: Briles Travis C. , Yu Su-Peng , Chang Lin , Xiang Chao , Guo Joel , Kinghorn David , Moille Gregory , Srinivasan Kartik , Bowers John E. , Papp Scott B.
Published: February 2021

Implementing optical-frequency combs with integrated photonics will enable wider use of precision timing signals. Here, we explore the generation of an octave-span, Kerr-microresonator frequency comb using hybrid integration of an InP distributed-feedback laser and a SiN photonic-integrated circuit. We demonstrate electrically pumped and fiber-packaged prototype systems, enabled by self-injection locking. This direct integration of a laser and a microresonator circuit without previously used intervening elements, such as optical modulators and isolators, necessitates understanding self-injection-locking dynamics with octave-span Kerr solitons. In particular, system architectures must adjust to the strong coupling of microresonator backscattering and laser-microresonator frequency detuning that we uncover here. Our work illustrates critical considerations toward realizing a self-referenced frequency comb with integrated photonics.
Further modeling of q95 windows for the suppression of edge localized modes by resonant magnetic perturbations in the DIII-D tokamak
Authors: Fitzpatrick R.
Published: February 2021

An improved resonant plasma response model that more accurately captures the physics of the interaction between a tokamak plasma and a resonant magnetic perturbation (RMP) is developed. The model interpolates between the linear and the nonlinear response regimes and takes into account the fact that the slip-frequency is non-zero in the nonlinear regime. The improved model is incorporated into the extended perturbed equilibrium code (EPEC) toroidal asymptotic matching code. The modified EPEC code is used to investigate RMP-induced edge-localized-mode (ELM) suppression in DIII-D H-mode discharge #145380. Somewhat surprisingly, allowing for a finite slip-frequency (i.e., relaxing the so-called no-slip constraint) is found to only slightly facilitate the locking of driven magnetic island chains to the RMP, and, hence, to only slightly facilitate RMP-induced ELM suppression. This is true despite the fact that the nature of non-locked island solutions is radically different when the no-slip constraint is imposed compared to when it is relaxed (in the first case, the widths of the island chains driven at the rational surfaces pulsate, and in the second case, they remain steady). The previously obtained conclusion that the response of a typical H-mode tokamak plasma to an RMP cannot be accurately modeled by linear theory is confirmed. The previously obtained conclusion that the best agreement between theory and observations is achieved by assuming that the natural frequencies of tearing modes, in the absence of the RMP, are determined by the local equilibrium E×B velocity is also confirmed.