Contact Situations Research Articles

Atomic Force Microscopy Analysis of Velocity Dependent Adhesive Viscoelastic Contact.

Adhesive contact phenomena play a crucial role in various scientific and engineering fields. However, considering viscoelasticity, which is essential for understanding practical applications involving soft materials like polymers, makes analysis challenging. Traditional elastic contact models such as the Johnson-Kendall-Roberts and Maugis-Dugdale models often fail to account for viscoelastic behavior. In this study, rate-dependent viscoelastic adhesive contacts were analyzed using atomic force microscopy force-distance curve measurements, comparing the elastic models with the viscoelastic model proposed by Barthel. The force curve analysis, conducted with the Barthel model for the first time, reveals that viscoelastic behaviors inside the contact area and the interaction zone both affect the contact state. These viscoelastic behaviors result in phenomena specific to viscoelastic contact, such as the "stick region" and the apparent work of adhesion. The Barthel model successfully captures the rate dependence of the contact situation, promoting a comprehensive understanding of viscoelastic adhesive contact phenomena.

The Norwegian language in Argentina: A first look at heritage Norwegian in a new context

This paper presents preliminary observations of Norwegian as a heritage language (HL) in a contact situation that has largely gone unnoticed up until now: Argentina, where Spanish is the main contact language. We discuss some lexical, morphological, and syntactic properties of Argentine Norwegian, with Norwegian as a HL in North America as a comparative backdrop, and we point out directions for future research.

Effect of shaft deflection on the dynamic behaviors of the ceramic bearing rotor system within wide temperature ranges

The shaft deflection has great impact on the dynamic characteristics of the ceramic bearing rotor system, which cannot be ignored within wide temperature ranges. This paper establishes a model considering the shaft deflection, and the impact of shaft deflection appears along with changes in bearing attitude. The interaction between the various components of the bearing is recalculated, and the dynamic behavior of the full ceramic bearing rotor system in wide temperature ranges is obtained based on the thermal deformation difference. The trends of dynamic behaviors with rotor mass, rotation speed and shaft length-diameter ratio are investigated, and comparisons between simulation and experimental results are conducted for verification. It is found that the shaft deflection makes impact by bringing in extra centrifugal force, and the effects are reflected in frequency components and trajectories. The simulation results with shaft deflection fit well with the experimental results, which proves that the dynamic model considering the shaft deflection better illustrates the dynamic behavior of the ceramic outer ring when the contact situations change with working temperature. The research carries out deep insight into the running of ceramic bearing rotor system, and provides guidance for the improvement of dynamic behaviors in wide temperature ranges.

Impact of border control measures on public health center operations and staffing at international airports during the emergence of the SARS-CoV-2 B.1.1.529 (Omicron) variant of concern

Objective Ota City, located in southeastern Tokyo, including Haneda Tokyo International Airport, has numerous scattered lodging facilities. Shortly after the first case of SARS-CoV-2 B.1.1.529 (Omicron) variant was reported abroad, the Japanese government strengthened border control measures, including quarantine procedures and public health official involvement, for incoming travelers. This study aims to propose effective and efficient border control measures to prevent future outbreaks of emerging and re-emerging infectious diseases.Methods Border control measures implemented between November 2021 and mid-January 2022 were analyzed from three perspectives: chronological changes in government notifications, the situation of in-flight contacts and Omicron cases, and the support system for coronavirus-disease 2019 control department of the Ota City Public Health Center. Additionally, a questionnaire survey was conducted among public health centers with jurisdiction over the top four international airports. This survey aimed to assess the effectiveness of the support system, evaluate cooperation with related organizations, identify common issues faced by public health concerns, and gather suggestions for improvements in future border control measures.Results The definition and treatment of in-flight contacts of Omicron-positive individuals were initially outlined on November 30, 2021, and underwent frequent revisions until January 14, 2022. Between December 1, 2021, and January 12, 2022, only one Omicron case was identified among the 470 tests conducted on in-flight contacts. However, out of 136 additional domestic specimens collected (including 57 positives for genetic analysis), 40 were confirmed Omicron positive. The results of the questionnaire survey across the four public health centers largely mirrored the issues and suggestions identified by Ota City officials. A significant portion of these issues arose from managing temporary non-Japanese residents staying near international airports.Conclusion Border control measures should be implemented to delay the domestic spread of the virus. In this reason, it is crucial to avoid placing an undue burden on public health officials responsible for handling domestic infections. Since response policies and target definitions may need to adapt to unknown pathogens, they may be changed frequently, baffling the officials; however, a system for collecting real-time data from frontline sites and making evidence-based decisions is essential. Additionally, deploying liaisons from national and prefectural governments to focal points of emergency response would strengthen the support system by promoting unified instructions and information sharing.

Multi-scale morphological analysis of brake lining surface and load-bearing arrangement in the contact

In the case of braking, a diversity of friction mechanisms occurs at the interface, caused by the heterogeneity of the composition, properties, and thermal phenomena. After friction, the obtained surfaces of the brake lining materials are highly heterogeneous. Load-bearing plates which are also called contact plateaus are formed with a compacted third body and constitute the sites of energy dissipation and sliding velocity accommodation. Their arrangement and preferential localizations in the contact constitute a key factor for the understanding of friction-induced phenomena and braking performance. Within this framework, a morphological characterization method has been set up based on several measurement techniques to explore the macroscopic and microscopic contact situation of the pad-disc system. The results show that exploiting Abbott curve parameters combined with roughness parameters is an effective way to give a detailed and comprehensive morphological description of the brake pad friction surface. It can be seen that the contact plateaus have preferential locations which give a particular load-bearing arrangement in the pad-disc interface which can be explained by friction and wear mechanisms. Results reveal also the main encountered difficulties, especially regarding the significance of scales and parameters describing the morphology of the friction material surface and the load-bearing plates disposition.

Sociophonetic Properties of Southern California English among Black and Latinx Teens

Descriptions of ethnolects in the U.S. have frequently focused on canonical, well-described features of these varieties, but less work has focused on how such features may overlap and spread into other ethnolects and local varieties in contact. Outside the U.S., the concept of the multiethnolect has been used to describe such situations of dialect contact, but little work has been done to document highly multiethnic dialect contact situations in the U.S. This study is among the first to provide a sociophonetic description of the distribution of features linked to different ethnolects, and to describe a situation of sustained U.S. contact dialect among youth from different racialized groups. Analysis of the speech of a group of Black and Latinx adolescents in Southern California reveals that these teens use a variety of sociophonetic features that have been previously linked to Chicano English (ChE) and African American English (AAE), as well as California Anglo English (CAE). I examine eight phonological variables previously described in these other varieties and reveal a complex sociolinguistic situation in which teens of both ethnicities appear to employ repertoires that draw on features of ChE, AAE, and CAE. I argue that the patterns of use I observe in this data provide evidence of a unique type of dialect contact situation that reflects ongoing trends in urban centers across the U.S.

Lexical Language Contact Phenomena: A Combined Model Based on the Vocabulario español-guarani (18th century)

Abstract The purpose of this work, which falls within the areas of lexicography (studying missionary linguistics) and sociolinguistics (studying cultural contact), is to analyse the linguistic and cultural contacts between Spanish and Guarani, based on lexicographic material extracted from the Vocabulario español-guarani by Pablo Restivo (1728). The basis of the analysis is provided by the names of animals—one of the ‘secular’ fields where the highest frequency of borrowings is found (Cerno & Obermeier 2013). The methodology applied is the Haspelmath model (2009) and the Gruda model (2018). The premise is that the arrival and work of the Jesuit missionaries created cultural contact that is reflected in the codified language and, in turn, in this dictionary of the time. The main contribution is a new combined model of lexical reflections in a situation of cultural contact that can be applied in the analysis of this kind of lexicographic work, while an additional section provides a presentation of Restivo’s work and its background.

A New Methodology for the Accurate Measurement of Tibiofemoral Kinematics in Human Cadaveric Knees: An Evaluation of the Anterior-Posterior Laxity Pre- and Post-Cruciate Ligament Resection.

Anterior-posterior (AP) stability is an important measure of knee performance after total knee arthroplasty (TKA). To improve the stabilizing effect of implants designed to compensate for the loss of the cruciate ligaments, it is important to understand the tibiofemoral contact situation within the native ligamentous situation of the knee and how it changes after cruciate ligament resection. This in vitro study introduces a new approach to accurately measure the tibiofemoral kinematics in a six-degrees-of-freedom joint motion simulator by tracking landmark-based coordinate systems and their corresponding bone geometries. The tibiofemoral contact situation was investigated by projecting the medial and lateral flexion facet centers onto the tibial plateau under AP shear forces across various flexion angles in thirteen knees. Tests were conducted pre- and post-cruciate ligament resection. Post-cruciate ligament resection, the femoral condyles shifted closer to or even exceeded the posterior border of the tibial plateau, but only slightly closer to the anterior border. This study presents a new methodology for measuring the tibiofemoral kinematics that can be applied to multiple loading profiles. It provides a basis for further investigations, including passive or active muscle forces, to enhance the design of total knee protheses and improve surgical outcomes.

Force Control of a Haptic Flexible-Link Antenna Based on a Lumped-Mass Model.

Haptic organs are common in nature and help animals to navigate environments where vision is not possible. Insects often use slender, lightweight, and flexible links as sensing antennae. These antennae have a muscle-endowed base that changes their orientation and an organ that senses the applied force and moment, enabling active sensing. Sensing antennae detect obstacles through contact during motion and even recognize objects. They can also push obstacles. In all these tasks, force control of the antenna is crucial. The objective of our research is to develop a haptic robotic system based on a sensing antenna, consisting of a very lightweight and slender flexible rod. In this context, the work presented here focuses on the force control of this device. To achieve this, (a) we develop a dynamic model of the antenna that moves under gravity and maintains point contact with an object, based on lumped-mass discretization of the rod; (b) we prove the robust stability property of the closed-loop system using the Routh stability criterion; and (c) based on this property, we design a robust force control system that performs efficiently regardless of the contact point with the object. We built a mechanical device replicating this sensing organ. It is a flexible link connected at one end to a 3D force-torque sensor, which is attached to a mechanical structure with two DC motors, providing azimuthal and elevation movements to the antenna. Our experiments in contact situations demonstrate the effectiveness of our control method.

Цифровая идентичность и гуманистическая модель цифровой образовательной среды

The article is devoted to the problems of subjective and personal self-determination of students in the situation of contact with the infocommunication environment, in particular, to the analysis of “digital identity”, symbolizing the emergence of a new modality of individual identification in virtual space. The methodological basis of the study was philosophical, axiological and systemic approaches. In addition, the possibilities of the method of existential analytics are used, which make it possible to explore not only ontological, but also the value-semantic contexts of the formation of personal identity, allowing us to consider the essence of “I” in the unique unity of its personal qualities, as well as content analysis as the optimal diagnostic tool network identity. The article conceptualizes the concept of “digital identity”. It is shown that the representation of the life of young people in a virtual environment, as one of the forms of successful socialization, as well as the possibility of constructing a virtual personality and its self-presentation in the external environment with the help of ideal self-images, determine the projective nature of digital identity, which is, ultimately, a set of projections of real identity, translated using digital technologies into a sign-symbolic context. Based on examples of the reverse influence of online identity on the real one, a conclusion is made about the emergence of a tendency to blur the lines between them, marking the beginning of the process of merging digital and real identities. The result of the study is a humanistic model of the digital educational environment (DEL), which sets the main variable vectors for its development and implementation, taking into account the creative potential of a particular teacher, the conditions of the educational organization, the socio-pedagogical and socio-psychological specifics of students.

Analysing the Dynamics of Language Change in Contact Situation A Case of Bilingual Speakers

Analysing the Dynamics of Language Change in Contact Situation A Case of Bilingual Speakers

A typological approach to language change in contact situations

Abstract Language contact phenomena have increasingly been researched from different historical linguistic, sociolinguistic and areal-typological perspectives. However, since most of this research is based on case studies, an assessment of contact phenomena from a worldwide comparative perspective has been missing in the literature. In this article, we draw inspiration from historical linguistics and language typology to present a new typological approach for evaluating evidence that given linguistic domains have been affected by language contact. This method has three parts: (1) a new approach to sampling, (2) the analysis of typological data, and (3) making probabilistic inferences about language contact. We argue that this is a parsimonious method for evaluating contact effects that can serve as a starting point for the further development of typological approaches to language contact.

An Acoustic Study on English Vowels Produced by Indonesian Speakers: Exploring Determining Factors and Contact Situations

An Acoustic Study on English Vowels Produced by Indonesian Speakers: Exploring Determining Factors and Contact Situations

The Chukchi Influence on Chaplinski Yupik

Abstract Chaplinski Yupik (also often referred to as Siberian Yupik), a critically endangered Eskimo language spoken on the Bering coast in the north-eastern Siberia, shows numerous traces of language contact with Chukchi. A striking example is Chaplinski Yupik personal names, a significant part of which have Chukchi origin. In this study Chaplinski Yupik names are analyzed based on the genealogies of Chaplinski Yupik people compiled in 1970–1980s. The article focuses on phonological and grammatical adaptation of Chukchi names in Chaplinski Yupik. The case of personal names clearly reflects the history of Chukchi-Yupik language contact in the area – from an asymmetrical contact situation (the knowledge of Chukchi was common among Yupik speakers but not vice versa) and regarding Chukchi as a more prestigious language to a gradual loss of Chukchi-Yupik bilingualism by the end of the 20th century.

WHEN CLITIC SYSTEMS COLLIDE, ANIMACY, FOR THE MOST PART, BEATS GENDER

In this paper we present elicitation results from an experiment on the acquisition of 3rd person object clitics by children of Paraguayan parents living in Buenos Aires and their mothers. These children are immersed in a situation of contact between two varieties of Spanish: the Paraguayan system (∅ for inanimate objects and LE for animate objects) and the local Argentinian system which uses LO for Masculine and LA for Feminine clitics. Results show that the Paraguayan mothers use substantially more LO/LA when compared with adults in Paraguay, as described by Choi (2000), suggesting a great deal of attrition. Their children on the other hand use far less LO/LA, but at the same time are not adopting as a group a LE/∅ system. Examining 19 Mother/Child dyads, we find that no children are exclusively using LO/LA users but some children are exclusively using LE/∅. As for mother we find some LO/LA users and the rest uses a mixed system. Interestingly, overall children use fewer forms than mothers.

Direct contact and very rapid valgus distortion characterise the injury mechanism of anterior cruciate ligament ruptures in judo.

To analyse anterior cruciate ligament (ACL) rupture (ACLR) injury mechanisms in competitive judo using systematic video analysis, focusing on contact situations and biomechanics. Seventeen videos of judo competitions wherein athletes developed ACLRswere included and retrospectively evaluated by five analysts. In all videos, the momentof initial contact and the index frame were defined. The judo techniques leading to the injury; the occurrence of direct contact, indirect contactor noncontact mechanisms; the time interval between the initial contact and index frame; the positions of the hip, kneeand foot in relation to the initial contact and index frame; and the balance status during the initial contact and index frame were recorded. Eleven (65%) of ACLRs in judo involved direct contact. The mean time interval between initial contact and index frame was 15 ± 22 ms. Thirteen (77%) athletes were not balanced at initial contact. In the index frame, the hip was abducted in all cases and in combination with internal rotation in 12 (71%) cases. From initial contact to index frame, hip flexion increased in all cases; at index frame, the knee joint was internally rotated relative to the trunk in 12 (71%) cases, and the knee flexion angles increased from the initial contact. In the index frame, the foot was externally rotated relative to the knee in 12 (71%) cases, and severe valgus development of the knee with valgus collapse was observed in 14 (82%) cases. A direct attack on the knee was the most common injury mechanism observed. Valgus distortion appears to be the most important component of the mechanism of injury. With this knowledge, 'modified defence reactions'for specific judo techniques can be developed to reduce the injury risk. Level IV.

Linguistic Variability across Four Generations of Basque Spanish Speakers

Abstract The present study uses the apparent-time construct to analyze cross-generational variability of the preverbal double negation construction (i.e., yo tampoco no voy a la fiesta ‘I’m not going to the party either’), traditionally cited as a regional characteristic of the Spanish spoken in the Basque Country. An acceptability judgment task and a semi-structured interview were carried out among four different age groups. The results show that speakers of the two older generations tend to accept and produce the regional construction significantly more than speakers of the two younger generations, who favor the Standard Spanish variant (yo tampoco voy a la fiesta ‘I’m not going to the party either’). It is suggested that this trend is mainly due to the participants’ different language contact situations (Thomason and Kaufman, 1988) and levels of formal education. Since older speakers grew up in a situation of shift via interference and with lower levels of formal education, they prefer the preverbal double negation construction, which was already a norm in the regional Spanish. However, younger speakers grew up in a language maintenance situation and have relatively high formal education levels, factors that have conditioned dialectal leveling in this case.

Interfacial thermal resistance between mechanically exfoliated nm-thick MoS2 and silicon from −60 °C to 50 °C based on ns-ET Raman technique

In the miniaturization and integration development of micro-devices, the large thermal contact resistance significantly affects the overall performance of micro-devices, which is influenced by both interfacial contact condition and material properties. However, the temperature dependence of interfacial thermal resistance of realistic materials remains unclear. In this work, the interfacial thermal resistance between nm-thick MoS2 nanosheets and Si substrate is measured by using the ns energy transport state-resolved Raman (ns ET-Raman) technique. By comparing the experimental data with finite difference numerical simulation, the real value of the interfacial thermal resistance is determined. By changing the ambient temperature from -60 °C to 50 °C, the interfacial thermal resistance against temperature curve is obtained. As the environmental temperature deviates from room temperature, a large increasement of the interfacial thermal resistance can be observed. As temperature goes back to room temperature, the unreversible interfacial thermal resistance indicates that the large thermal expansion mismatch deteriorates the contact situation. In the last, the interfacial thermal resistance evolution under varying environmental temperatures from both experiments and modeling results in literatures are compared and discussed to illustrate the effect of different interface formation methods. For epitaxial and CVD grown materials, the interfacial thermal resistance generally reduces with raising ambient temperature. While for mechanically exfoliated samples, the effect of thermal expansion mismatch and the resulting gaps dominate the interfacial thermal resistance, which leads to non-monotonous temperature dependency with a valley located at room temperature.

Navigating Identity: A Study of the Khasis in Meghalaya's Multilingual Borderlands

This paper attempts to study the factors that influence identity perception of the Khasis in a language contact environment in four borders of Meghalaya. The study finds that the ecology of contact, intermarriage, and migration play a significant role in shaping the linguistic and cultural identity perception of the Khasis. The study also demonstrates that the language that people use in a particular community is not just a matter of communication, but is also influenced by the social and cultural context of the contact environment. Apart from utility and value, the kind of motivation associated with language can perceptively affect one’s language and cultural identity. The study provides valuable insights into the complex factors that influence cross-border multilingualism and its impact on identity formation. The findings of the study have implications for the understanding of multilingualism in a contact situation on one hand, and the underpinnings of language and cultural in identity formation.

Developing linear-elastic material models for pressure measurement films in steel-steel and wheel-rail contact

Abstract The contact between two steel components can be identified by using multiple methods, for example, by experiment using pressure measurement films or by computational simulations with finite element analysis (FEA). For FEA material models of all components are required. When the experimental setup of an implemented pressure measurement film is reproduced simulatively, material models for the films are also necessary. Here, we developed linear-elastic material models for pressure measurement films which allow to simulate steel-film-steel contact situations. The material models were developed for Hertzian contact situations and afterward validated for the non-Hertzian wheel-rail contact. It was possible to develop material models for two different pressure measurement film types. In the case of a third film type, the developed model could not be validated successfully.