bluuebunny/crossref_metadata_2025_split huggingface dataset:
3D Finite Element Simulation of Processing of Generalized Newtonian Fluids in Counter-rotating and Tangential TSE and Die Combination
Authors: Malik M. , Kalyon D. M. 
Published: March 2022

Abstract
A full three-dimensional finite element analysis of the nonisothermal flow of generalized non-Newtonian fluids in counter-rotating tangential twin screw extruder is presented. Previous studies of the simulation of processing in tangential twin screw extruders have focused solely on the twin screw extruder, whereas here the coupled flow and heat transfer occurring in the integrated geometry of the extruder, connected to a die are considered. The FEM based numerical simulation of the coupled momentum-mass-energy conservation equations allowed the determination of the effects of some of the important system parameters, including the power law index and the staggering angle of the screws, on the pumping and pressurization capability of the extruder and the associated degree of fill in the extruder.
Melt Intercalation in Montmorillonite/Polystyrene Nanocomposites
Authors: Nassar N. , Utracki L. A. , Kamal M. R. 
Published: March 2022

AbstractAtactic polystyrene (PS) was used to study the effect of flow field (shear and/or elongational) on the intercalation of polymer/clay nanocomposites (PNC). Three grades of (PS), with different molecular weights, were compounded with an ammonium-modified montmorillonite (Cloisite 10A) in a twin-screw extruder (TSE). The compounds were subsequently fed to a single screw extruder, fitted with one of three specially designed torpedo-attachments. The attachments were designed to provide combinations of different levels of shear and elongational deformations. The resins, TSE compounds, and final PNC’s were characterized for the degree of intercalation, degradation, rheological behavior, and mechanical properties. The data showed that the thermal decomposition of the quaternary ammonium intercalant caused severe damage to both PNC components: a collapse of the organoclay interlayer spacing, and the thermo-oxidative degradation of PS. In spite of these detrimental effects, the attachment employing combined elongational and shear flow resulted in generally larger gallery spacing and more improvement of the mechanical properties than the other two attachments.
Eurasian oystercatcher optimiser: New meta-heuristic algorithm
Authors: Salim Ahmad , Jummar Wisam K. , Jasim Farah Maath , Yousif Mohammed 
Published: March 2022

AbstractModern optimisation is increasingly relying on meta-heuristic methods. This study presents a new meta-heuristic optimisation algorithm called Eurasian oystercatcher optimiser (EOO). The EOO algorithm mimics food behaviour of Eurasian oystercatcher (EO) in searching for mussels. In EOO, each bird (solution) in the population acts as a search agent. The EO changes the candidate mussel according to the best solutions to finally eat the best mussel (optimal result). A balance must be achieved among the size, calories, and energy of mussels. The proposed algorithm is benchmarked on 58 test functions of three phases (unimodal, multimodal, and fixed-diminution multimodal) and compared with several important algorithms as follows: particle swarm optimiser, grey wolf optimiser, biogeography based optimisation, gravitational search algorithm, and artificial bee colony. Finally, the results of the test functions prove that the proposed algorithm is able to provide very competitive results in terms of improved exploration and exploitation balances and local optima avoidance.
Factors affecting utilization of CT scan following ultrasound evaluation of suspected appendicitis
Authors: Zisman Adam , Novi Brian , Gaughan John , Carr Lauren 
Published: March 2022

Abstract

Context
When evaluating a pediatric patient in the emergency department for suspected appendicitis, a provider is often faced with the dilemma of deciding if a computed tomography (CT) scan is warranted when—as is most often the case—ultrasound results do not yield a definitive diagnosis. The potential risks of radiation must be weighed against numerous aspects of a patient’s background, physical exam, and already-obtained workup.

Objectives
This study aims to aid in future decision making of providers in their evaluation of patients with suspected appendicitis, to help facilitate a more comprehensive answer to the “next-steps” in the question of equivocal ultrasound, and to create a pathway utilizing lab results, physical exam findings, and pertinent positives and negatives in patient history to facilitate a more objective decision-making process for ordering a CT scan.

Methods
A retrospective chart review was performed for patients who were evaluated for possible appendicitis at our institution between October 2016 and October 2017 and whose ultrasound results were equivocal. We determined what factors led to increased frequency of obtaining CT scans.

Results
Statistical analysis showed that several factors were independently associated with the increased likelihood of having a CT scan performed. When considered in combination with the other parameters, it was found that older children, males, report of right lower quadrant (RLQ) pain, and presence of RLQ tenderness on physical exam were all associated with a significantly higher likelihood of having a CT scan performed.

Conclusions
When combined with present algorithms and protocols already in use, this information can assist the provider in making prudent decisions for their patients with the potential for reduced provider bias.
Customer knowledge and behavior on the use of food refrigerated display cabinets: A Portuguese case
Authors: Gonçalves João Carlos , Guiné Raquel P. F. , Amoedo Carolina , Correia Paula 
Published: March 2022

Abstract
This article presents a study on customer knowledge and habits regarding the use of refrigerated display cabinets (RDC). The study was carried out on a sample of Portuguese retail stores’ customers, using a questionnaire survey available through an Internet platform. The sample consisted of 136 individuals, who voluntarily participated in the study. Questions included the characterization of the sociodemographic population involved. The questionnaire included different questions to related with RDC, namely customer knowledge about the appearance of each RDC equipment, questions to evaluate the respondents’ perception about the advantages and disadvantages related to open or glass-door closed RDC, questions to assess the participants’ habits and behavior when purchasing food products from glass-door closed RDC (frequency and duration of door open), questions to characterize the consumers’ habits on purchasing food products from RDC, and also questions to characterize the consumers’ shopping attitudes in the context of the COVID-19 pandemic, caused by SARS-CoV-2. The results seem to indicate that customers prefer closed RDC; for example, 61.8% of participants prefer products preserved in glass-door closed RDC, against 6.6% that admit to preferring products preserved in open RDC. Therefore, we can deduce that the existence of doors does not appear to be an obstacle to purchasing food products. Regarding the use of glass-door closed RDC, 80.1% of the participants say they just open the door once, and 53.7% of the costumers believe they keep the door open in the interval [4‒6 s]. This indicates that Portuguese customers are quite well informed about food safety issues and seem to follow assertive attitudes when purchasing food products from RDC. This study reinforces the benefits of replacing open RDC by closed glass-doors allowing significant energy savings.
Gefügeentwicklung durch Wärmebehandlung an Magnesiumlötverbindungen
Authors: Wielage Bernhard , Mücklich Silke 
Published: March 2022

Kurzfassung
Lötverbindungen mit Zn-Mg-Al-Loten an Magnesiumgrundwerkstoffen bilden in Abhängigkeit vom Grundwerkstoff und von der eingesetzten Lotlegierung sehr unterschiedliche Gefüge aus. Wie bereits in [1] beschrieben, kommt es bei Einsatz binärer Mg-Zn-Lote zu der Beobachtung, dass das Lot bedingt durch die beschleunigte Abkühlung während des Lötvorganges kein feinlamellares eutektisches Gefüge ausbildet, sondern in einem Gemisch mikrokristalliner, intermetallischer Phasen erstarrt. Da sich diese Morphologie negativ auf die mechanischen Eigenschaften auswirkt, wird versucht, durch eine nachgeschaltete Wärmebehandlung eine günstigere Gefügeausbildung zu erzielen.
Einfluss von thermomechanischer Behandlung auf die Mikrostruktur von pseudoelastischem NiTi am Beispiel von Komponenten für Brillengestelle
Authors: Frotscher M. , Menges C. , Diehl O. Th. , Eggeler G. 
Published: March 2022

Kurzfassung
Eines der in der Literatur am häufigsten aufgeführten Anwendungsbeispiele für Nickel-Titan-Formgedächtnislegierungen (NiTi-FGL) sind Komponenten für Brillengestelle [1, 2, 3]. Dabei werden insbesondere die Nasen- und Seitenbügel, sowie Verbindungselemente aus diesem Werkstoff hergestellt [4, 5, 6]. Für den Nutzer hat dies den großen Vorteil einer erhöhten Flexibilität bei erzwungener Verformung zum Beispiel beim Verbiegen oder Herunterfallen der Brille. Im Rahmen der vorliegenden Arbeit wurden Brillenkomponenten verschiedener Hersteller aus NiTi mit Hilfe von rasterelektronenmikroskopischen Methoden untersucht. Die Proben wurden dabei verschiedenen thermomechanischen Behandlungen unterzogen, um deren Auswirkung auf die Mikrostruktur und sowie auf die funktionellen und strukturellen Eigenschaften zu charakterisieren.
TEM Study of Bainitic Low-Carbon HSLA Steel: The Orientation Relationships of Cementite
Authors: Illescas Silvia , Fernández Javier , Asensio Juan , Guilemany Josep Maria 
Published: March 2022

Abstract
Two different bainitic structures can be present in steel depending on the heat treatment to which the samples are subjected. The two different types of bainitic structures exhibit a different orientation relationship between the cementite and the ferrite matrix. The Pitsch orientation relationship is observed in upper bainite while the Bagaryatski orientation relationship is observed in lower bainite [1]. Different heat treatment samples of low-carbon High Strength Low Alloy (HSLA) steel were studied using TEM observations in order to ascertain the orientation relationship between ferrite and carbide in the different bainitic structures and to determine whether this relationship may indicate the type of bainitic structure.
Electrical conductivity and thermal stability of surface-modified multiwalled carbon nanotubes/polysulfone/poly(p-phenylenediamine) composites
Authors: Abdelhamid Ahmed E. , Ward Azza A. , Khalil Ahmed M. 
Published: March 2022

Abstract
Multiwalled carbon nanotubes (MWCNTs) were functionalized with acid then coated with poly(p-phenylenediamine) (PpPD). Various concentrations of modified multiwalled carbon nanotubes (MWCNTs@PpPD) were introduced to a polysulfone (PSU) and poly(p-phenylenediamine) (PpPD) blend providing nanocomposites in form of sheets. Chemical oxidative polymerization was used to polymerize p-phenylenediamine. PpPD is then applied as a compatibilizer in such heterogeneous system to facilitate a successful percolation for MWCNTs in the polymeric matrix as an enhanced conductive filler. The morphological investigations showed homogeneous distribution for MWCNTs in the polymeric matrix. The prepared composites were investigated demonstrating favorable thermal and electrical properties. Thermogravimetric analysis (TGA) emphasized that MWCNTs@PpPD contributed in enhancing the thermal stability of the prepared sheets. The electrical conductivity of PSU/PpPD/MWCNTs@PpPD nanocomposites boosted upon raising the magnitude of loaded MWCNTs. The existence of MWCNTs@PpPD in the polymeric matrix extended the interfacial polarization effects with elevating the conductance. The loaded composite with (7.5 wt%) MWCNTs@PpPD showed the optimum electrical conductivity values. It was then treated with HCl to protonate the amine groups in PpPD showing higher conductivity value than its corresponding untreated one. PpPD and MWCNTs contributed synergistically in modifying the insulation feature of PSU to a favorable electrical conductivity one.
Influence of hydrothermal aging on the mechanical performance of foam core sandwich panels subjected to low-velocity impact
Authors: Liu Youping , Wu Ye 
Published: March 2022

Abstract
The effect of hydrothermal aging on the impact resistance of foam core sandwich panels is studied in this study. The sandwich panels with glass fiber-reinforced skins and polyurethane foam core were fabricated and then were treated with different hydrothermal aging conditions. The moisture absorption characteristic of the composite skins was evaluated. A modified Fickian formulation was proposed to predict the moisture absorption behavior of composite skins. The low-velocity impact resistance of the aged sandwich panels was determined at three different impact energies. The impact responses including contact force, deflection, and dissipated energy of the sandwich panels with and without hydrothermal aging were analyzed. The macroscopic and microscopic damage morphologies were observed by visual inspection and scanning electron microscope methods, respectively. The damage mechanism of the aged panels was revealed. Results indicate that the impact resistance of aged sandwich panels is degraded, and the performance degradation is larger with increasing aging temperature. Compared to the panel without hydrothermal aging, the reduction of the contact force is 35.69%, and the increase of the deflection is 71.43% for the aged panel at 70°C aging temperature. The fiber/matrix interfacial cohesive performance is degraded resulting from the hydrothermal aging.
Technologiemanagement – ein Kernprozess für Unternehmen
Authors: Schuh Günther , Klappert Sascha , Moll Torsten 
Published: March 2022

Abstract
Die Schnelllebigkeit von Technologien ist häufig der Grund dafür, dass Unternehmen neue Technologien nicht rechtzeitig erkennen oder einführen. Doch gerade die Identifikation neuster Technologien und das frühzeitige Erkennen daraus resultierender Chancen sichert in der Konsequenz den langfristigen Unternehmenserfolg. Eine systematisch betriebene Technologiefrüherkennung und die Verwendung von geeigneten Werkzeugen, wie zum Beispiel der Technologiroadmap, sind hier entsprechende Ansätze des Technologiemanagements, die in der unternehmerischen Praxis etabliert werden müssen. In diesem Artikel wird beschrieben, wie die Aufgaben der Technologiefrüherkennung mit geeigneten Hilfsmitteln im Unternehmen auch über verschiedene Bereiche hinweg verankert werden können, um dadurch das Fundament für ein erfolgreiches Technologiemanagement zu legen. Hierbei steht als zentrale Herausforderung auch die Bündelung der Aktivitäten des Technologiemanagements durch die Integration verschiedener Abteilungen und Unternehmensbereiche im Fokus der Betrachtung.
Kompetenzzellenbasierte Optimierung von Werkstattstrukturen hilft Kosten senken
Authors: Strunz Matthias , Nobis Senftenberg, Thomas 
Published: March 2022

Abstract
In Zukunft werden Unternehmen zunehmend ihre Ressourcen in Form von eigenständig lebensfähigen Kompetenzzellen bereitstellen. In diesem Artikel wird hierzu ein Ansatz vorgestellt, der die optimale Gestaltung von sensiblen Dienstleistungsstrukturen in Unternehmen in der frühen Planungsphase zum Ziel hat, um das Investitionsrisiko zu verringern. Auf der Basis des Leistungsprogramms von Serviceunternehmen generiert der Planer Kompetenzzellen, die miteinander funktions- und/oder prozessorientiert vernetzt werden können. Der Einsatz digitaler Visualisierungssysteme, die den Planungsprozess, beginnend bei der Projektidee über die Planung und Vorbereitung bis zu deren Umsetzung in funktionsfähige Kompetenzzellen und deren Vernetzung wesentlich unterstützen und verkürzen, wird an einem praktischen Beispiel dargestellt.
Integriertes Abzugssystem für das Weben von Spacer Preforms für textilverstärkte Verbund-Bauteile
Authors: Großmann Knut , Mühl Andreas , Löser Michael , Holowenko Olaf , Möbius Volker 
Published: March 2022

Abstract
Für das Heißpressen hohlraumbehafteter, textilverstärkter thermoplastischer Verbund-Bauteile werden textile Preforms benötigt. Am SFB 639 der TU Dresden wird der Prozessketten verkürzende Ansatz verfolgt, diese Preforms aus Hybridgarnen, die die Verstärkungsfaser und die Matrix-Komponente bereits enthalten, endformnah als Spacer Fabrics webtechnisch herzustellen. Im ersten Teil des Beitrags wurden das Konzept und die Konstruktion dieses integrierten Abzugssystems behandelt. Der zweite Teil beschreibt zuerst ein entwicklungsbegleitend einsetzbares Simulationsmodell zur Berechnung der dynamischen Wechselwirkungen zwischen Webmaschine sowie Abzugs- und Fadensystem. Anschließend wird für die Anlage die funktionale Systemstruktur abgeleitet und die darauf aufbauende Steuerungsentwicklung dargestellt. Die Beschreibung eines Emulators, mit dessen Hilfe die Steuerungsinbetriebnahme unterstützt wird, beschließt den Artikel.*
Determiningcarrot preservation depending on the root quality and size, as well as on storage techniques
Authors: Pusik Ludmila , Pusik Vlаdimir , Bondarenko Veronika , Gaevaya Ludmila , Kyruchina Natalja , Kuts Oleksandr , Slobodianyk Galina , Nakloka Olga 
Published: March 2022

This study aimsto scientifically substantiate the influence of the quality, size of carrot roots, as well as storage techniques, on safety that couldprolong their consumption.
The research into carrot roots has not been developed properly. In this regard, it is important to conduct comprehensive studies of objective indicators that exert the greatest impact on the intensity of natural weight loss of carrot roots and their preservation. The study reported here aimed to scientifically substantiate the influence of the quality, size of carrot roots,as well as storage techniques, on safety, which could allow them to be consumed longer.
It has been theoretically substantiated and experimentally confirmed that the longest storage period of 206 days with a commercial yield of 89.27 %characterized large root crops. The output of marketable products of medium root crops was 86.56 %, small ones after 161 days ‒ 80.30 %. Compared with large root crops, the shelf life of both small and mechanically damaged carrots decreased by 46 days, and the yield of marketable products decreased by 9.0 and 11.1 %, respectively. Carrot roots damaged by pests were preserved almost the same as chopped ones. On average, over 191–192 days of storage, the yield of marketable products amounted to 83.43 and 83.90 %, respectively. The shortest shelf life (142) and the worst preservation (68.34 %)were observed in carrots with a torn peel, due to a large number of diseased root crops (18.53 and defective ones (6.85 %).
Storage of carrots in boxes at a permanent storage facility with forced-air and exhaust natural ventilation turned out to be ineffective. The yield of marketable products amounted to 85.5 %. The highest safety of 96.3–94.3 % was observed when the roots were stored in plastic bags and perforated bags, respectively. A greater yield of marketable products is provided by bags with a capacity of 5 kg. It was found that the storage in cardboard boxes and paper bags contributed to the development of microorganisms. The number of affected root crops ranged from 2.4 to 2.8 %.
Optimization of the control system for an electric power system operating on a constant-power hyperbole
Authors: Budashko Vitalii , Sandler Albert , Shevchenko Valerii 
Published: March 2022

For an electric power system (EPS) of the combined propulsion complex (CPC), working on a constant-power hyperbola (CPH), the strategy of managing power distribution between propulsion electric motors and own needs consumers has been improved. The study reported here aimed to reduce fluctuations in current consumption and load by optimizing voltage controllers and the rotation frequency of generator assemblies (GA). The system of EPS GA voltage and frequency stabilization was synthesized by determining, in the system of equations, the dynamics of the values of EPS links' time constants and the coefficients that correspond to control parameters. To define the characteristics of the control signals from the regulators of EPS GA rotation frequency and excitation voltage, the laws that control the speed and excitation current were calculated. After sampling the coefficients of the GA speed control regulator, the tasks for the excitation voltage controller were determined. The methodology of data acquisition was applied on the basis of a correlation between the EPS characteristics and the experimental characteristics of GA. The system of EPS dynamics equations was optimized in accordance with the structure and settings of the optimal controller and the probability of a situational error by using Spearman's rank correlation coefficient. The optimization has made it possible to reduce the likelihood of a situational error during the synchronization of GA and enable the stable operation of GA close to the mode of operation on CPH. The power controller was tested under the mode of changing the load of own needs with the power levels of EPS on CPH in the range of 50‒100 % of the rated power. The range of deviations of the current consumed with an enabled GA rotation controller was 10 % of the average value. The range of EPS power deviations with the power controller turned on was 5 %.
Optimizing the partial gear ratios of the two-stage worm gearbox for minimizing total gearbox cost
Authors: Quang Nguyen Huu , Linh Nguyen Hong , Huy Trieu Quy , Lam Pham Duc , Tuan Nguyen Anh , Ngoc Nguyen Dinh , Hung Le Xuan , Pi Vu Ngoc 
Published: March 2022

Optimizing the design of a worm gearbox is complex to get due to considering multiple objectives and numerous main design parameters. Hence, a more consistent and robust optimization technique will be considered in obtaining the optimized results. This paper presents the optimization process of the Two-Stage Worm Gearbox with the objective function of minimizing total gearbox cost. Ten main design parameters are chosen as input parameters for evaluating their impacts on the response of the partial gear ratio u2. In this study, the simulation experiments were used, which do not need cost to perform all potential tests. In order to do this, a 2^(10-3) model and using 1/16 fractional model were selected due to the limitation of the built-in function in Minitab@18. Moreover, the screening experiments are purposely used to determine the number of parameters, which has a minor influence on the response. Compared to using the Taguchi technique, the model of 2^11 corresponding to L32 or 32 tests is a simple method to achieve the objectives.
The results show that Total gearbox ratio exhibits the biggest effect on the response compared to others. Furthermore, the interactions between these factors to the remaining are significant. The high reliability of the proposed model is verified by simulation experiments. The random tendency of data shows that u2 is not crucially influenced by other than the input parameters. The data in versus order prove that the response is not varied to the time factor. Moreover, the coefficients of adjusted R2 and R2 are both greater than 99 %, it can be concluded that the proposed regression model is appropriate. The proposed optimization process in this study is reliable and the optimal design method can provide a useful reference on performance improvement of other worm gears.