A generalized tube model of rubber elasticity

Soft Matter ◽  
2021 ◽  
Author(s):  
Ehsan Darabi ◽  
Mikhail Itskov

A new type of micro-mechanically motivated chain network model for rubber-like materials is proposed. The model demonstrates how the local molecular constraints modify under deformation and shows the impact of these changes on the macroscopic elasticity of the material.

Author(s):  
Keyu Qin ◽  
Haijun Huang ◽  
Jingya Liu ◽  
Liwen Yan ◽  
Yanxia Liu ◽  
...  

Islands are one of the most sensitive interfaces between global changes and land and sea dynamic effects, with high sensitivity and low stability. Therefore, under the dynamic coupling effect of human activities and frequent natural disasters, the vulnerability of the ecological environment of islands shows the characteristics of complexity and diversity. For the protection of island ecosystems, a system for the assessment of island ecosystems and studies on the mechanism of island ecological vulnerability are highly crucial. In this study, the North and South Changshan Islands of China were selected as the study area. Considering various impact factors of island ecological vulnerability, the geographical information systems (GIS) spatial analysis, field surveys, data sampling were used to evaluate island ecological vulnerability. The Bayesian network model was used to explore the impact mechanism of ecological vulnerability. The results showed that the ecological vulnerability of the North Changshan Island is higher than that of the South Changshan Island. Among all the indicators, the proportion of net primary productivity (NPP) and the steep slope has the strongest correlation with ecological vulnerability. This study can be used as references in the relevant departments to formulate management policies and promote the sustainable development of islands and their surrounding waters


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Ying Yu ◽  
Yirui Wang ◽  
Shangce Gao ◽  
Zheng Tang

With the impact of global internationalization, tourism economy has also been a rapid development. The increasing interest aroused by more advanced forecasting methods leads us to innovate forecasting methods. In this paper, the seasonal trend autoregressive integrated moving averages with dendritic neural network model (SA-D model) is proposed to perform the tourism demand forecasting. First, we use the seasonal trend autoregressive integrated moving averages model (SARIMA model) to exclude the long-term linear trend and then train the residual data by the dendritic neural network model and make a short-term prediction. As the result showed in this paper, the SA-D model can achieve considerably better predictive performances. In order to demonstrate the effectiveness of the SA-D model, we also use the data that other authors used in the other models and compare the results. It also proved that the SA-D model achieved good predictive performances in terms of the normalized mean square error, absolute percentage of error, and correlation coefficient.


2020 ◽  
Author(s):  
Sari Goldstein Ferber ◽  
Gal Shoval ◽  
Viviana Trezza ◽  
Giorgio Di Lorenzo ◽  
Rodolfo Rossi ◽  
...  

Author(s):  
Begüm Aylin Önder

Corporate social responsibility is one of the activities that goes beyond philanthropy, based on volunteerism in line with the responsibilities of enterprises towards society. This concept, which offers businesses the opportunity to look after and develop their brand image in the eyes of society, has become a necessity, not a choice, especially in today's world. In order to meet social expectations, the effectiveness of static and dynamic advertising messages implemented in all social benefit-based studies for human development such as environment, health and education is very important in terms of ensuring audience communication. In the second half of 2019, people were confined to homes and life came to a standstill all over the world in order to reduce and prevent the impact of the pandemic within the scope of the “New Type Corona Virus” (COVID-19) measures, which are from the sars-cov-2 coronavirus family, which is spreading rapidly globally starting from Wohan, Hubei Province, China. As a basic protection module for humanity against corona virus, it has incorporated the concept of social distancing into their lives in order to reduce the contact of staying at home and increasing hygiene, except in mandatory situations. During this extraordinary period, many brands on a global scale have included the concept of “social distance” in their advertising messages with the awareness of corporate social responsibility and have started to inform and educate the community about this issue by emphasizing the importance of the process. Within the scope of this research, advertising designs prepared by brands acting with corporate social responsibility awareness through the concept of social distancing during the Pandemic period were discussed and how the meaning structures behind the messages were created and transmitted. The research is limited to 3 (three) advertising designs determined by the 'judicial sampling' method (selective method). In the sample of the study, advertising narratives of brands in different sectors were explained in general framework and similar and different aspects of messages were uncovered by performing comparative analysis between messages in line with the findings obtained from the narratives. In this context, it was determined that the contrasts of “pessimism and optimism, hope and despair, happiness and unhappiness, death and life, strong and powerless, youth and old age, unity/togetherness and separation, struggle and defeat, nature and culture” were constructed as the main discourse.


Author(s):  
Maryam Salahshour ◽  
Halina Mohamed Dahlan ◽  
Noorminshah A. Iahad

Social networking tools have become an integral part of our daily lives. Recently, a new type of Social Networking Sites (SNSs) namely Academic Social Networking sites (ASNSs) has attracted global users. There is perceived usefulness on the impact of ASNSs on patterns of academic research activities. However, it remains unclear why some researchers do not use ASNSs at all. The purpose of this paper is therefore to explore the ASNSs usage among Malaysian academic researchers and to investigate benefits, specific purpose, drivers and barriers of using ASNSs. A total of 210 completed cases were collected through paper-based and online-based questionnaire. In order to show the outcome of the research, descriptive interpretation of data is performed. The overall findings of this research indicate that there is low rate of ASNSs usage among researchers. In addition, the results show that colleagues, attitude toward technology and communication benefits are the drivers to use ASNSs and trust, privacy and security are the common barriers regarding to use ASNSs.


1983 ◽  
Vol 105 (4) ◽  
pp. 719-725 ◽  
Author(s):  
M. A. Hebbar ◽  
C. E. Sessions

The impact of Materials and Processes (M and P) development activities at the Nuclear Components Division - Breeder Reactor Components Project of Westinghouse are described. Nine specific M and P programs have been performed over the past five years and the conclusions drawn from each are summarized herein. These engineering activities could be classified as component design, fabrication, and testing results. However, the discussion presented is from a materials engineer’s viewpoint as to how the previously proposed development tasks have answered existing questions about either design, manufacturing, or plant operation. The nine areas which are discussed include (i) double-wall tubing, (ii) tube-to-tubesheet welding, (iii) few tube model fabrication and testing, (iv) tube support plates, (v) shell welding, (vi) convoluted shell expansion joint, (vii) water chemistry and corrosion behavior, (viii) chemical cleaning, and (ix) surface contamination protection.


2018 ◽  
Vol 38 (2) ◽  
pp. 242-252
Author(s):  
Jianrong Yang ◽  
Zhiyu Zhang

A new concept of a flexible rock-shed is presented for protection of the railway from falling rocks. The flexible rock-shed is made of flexible nets connected by specific spring spacer bars to an array of reinforced concrete portable frames which are linked by a longitudinal steel tube truss. To evaluate the performance of the flexible rock-shed, experimental and numerical studies are carried out in the present study. Impact tests are conducted on a full-scale partial model of the prototype structure when it is subjected to a falling block of 340 kg. The impact time interval, maximum deflection of the flexible net, tensile forces in the supporting ropes, and axial strains of spring spacer bars are recorded. To further examine the dynamic behavior of the flexible rock-shed, numerical simulations are also carried out by using the explicit finite element code ANSYS/LS-DYNA. It is found that the numerical results coincide well with the experimental data and both the numerical and experimental studies reveal that the structure can withstand impact energy of 50 kJ with all the materials working in the elastic range. The structural details are improved and the basis for the design and construction of similar structures in the future is provided.<br>


Author(s):  
Alika Guchua

Abstract: The article deals with new type of asymmetric warfare and hybrid war. The potential threats in international politics and global security issues, Euro-Atlantic Alliance policy of fighting against terrorism. A serious challenge to modern security creates many problems around the world. The beginning of the twenty-first century was marked by proliferation of hybrid wars, held between flexible and sophisticated adversaries engaged in asymmetric conflicts using various forms. The hybrid war is caused by a hybrid threat, a blend of military and non-military assets and operations, terrorism, guerrilla tactics, criminality and cyber attacks. The use of hybrid type tactics can ensure the achievement of the main objectives of an international actor, with a minimum of effort, usually without using the force, and can deny to the target/victim the possibility to take any defensive actions. The complexity, diversity, the nature and dynamics of contemporary conflicts represent challenges that should be widely studied. The war, be it ancient or modern, hybrid or not, is always complex and cannot be described by a single adjective. The work focuses on the role of NATO in ensuring peace worldwide in the context of new asymmetric threats. The aim of the research topic: analyzing global challenges, which pose a serious threat to international security.


Author(s):  
I.P. Timofeev ◽  

The author offers a network model of the economic system designed to research the impact of increasing technological division of labor on the opportunities for economic development and growth. The article describes the main elements of the model and their economic interpretation, as well as the basic rules for its construction. An economic network consists of sets of producers, consumers and goods flows between them. The author shows how the model represents the appearance of various types of innovations. The author has outlined main directions of further development and researching the model.


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