scholarly journals Development of a composite friction modifier with carbon nanotubes for applications at the wheel–rail interface

2020 ◽  
Vol 29 ◽  
pp. 2633366X2093001
Author(s):  
Juan Camilo Vélez ◽  
Jesús Antonio Carlos Cornelio ◽  
Robinson Buitrago Sierra ◽  
Juan Felipe Santa ◽  
Lina Marcela Hoyos-Palacio ◽  
...  

Wear of wheels and rails is a major problem in railway transportation industry. Solid lubricants constitute a cost-efficient alternative to control wear and friction at the wheel–rail interface, especially when a fine-tuned balance between traction force and energy consumption is sought. In this work, composite friction modifiers (CFMs) composed of a vinyl ester matrix reinforced with molybdenum disulfide and carbon nanotubes were developed. The total solid additive content was less than a half in comparison with a commercial product available on the market, which was used as a reference. A benchmarking study of the CFM was carried out by means of tribological tests in a twin-disc machine at a contact pressure of 1.1 GPa and different slip values. The results indicated that the developed CFM reduce coefficient of traction by 10% compared to unlubricated conditions that is similar to the reference. However, the total mass loss of steel components due to wear under CFM lubrication was lower than in the reference test.

2017 ◽  
Vol 5 (5) ◽  
pp. e1320 ◽  
Author(s):  
Martin Aman ◽  
Matthias E. Sporer ◽  
Otto Riedl ◽  
Wei-Te Wang ◽  
Anne Kramer ◽  
...  

Author(s):  
Sundaravalli Narayanaswami

This chapter is intended as an exposure to OR based methods, particularly the analytical approach to modelling railway operations. An overview of several planned operations in railway transportation is provided in an academic context. Some of the applications and the associated models are applied in realistic settings in the transportation industry, and also have demonstrated evidence of acceptance over a long number of years. Primary coverage is on transportation scheduling and the concise discussions are on planning phases, various operations that can be deterministically modeled and analysed, model development, few exercises and real-world stories, wherever appropriate. All sections are adequately provided with the list of references and an interested reader can benefit from a conceptual understanding to model development and to implement and deploy, under some prior knowledge on the basics and programming experience.


2020 ◽  
Vol 248 ◽  
pp. 119189 ◽  
Author(s):  
Muhammad Abdul Qyyum ◽  
Kinza Qadeer ◽  
Ashfaq Ahmad ◽  
Faisal Ahmed ◽  
Moonyong Lee

Author(s):  
A. Krzyżak ◽  
E. Kosicka ◽  
R. Szczepaniak ◽  
T. Szymczak

Purpose: Carbon nanotubes are used in composite materials due to the improvement of (including tribological) properties of composites, especially thermoplastic matrix composites. This demonstrates the potential of CNTs and the validity of research on determining the impact of this type of reinforcement on the composite materials under development. Design/methodology/approach: The article presents selected results of research on polymer composites made of C.E.S. R70 resin, C.E.S. H72 hardener with the addition of a physical friction modifier (CNTs) with a percentage by volume of 18.16% and 24.42%, respectively, which also acts as a reinforcement. The produced material was subjected to hardness measurements according to the Shore method and EDS analysis. The study of abrasive wear in reciprocating movement was carried out using the Taber Linear Abraser model 5750 tribotester and a precision weight. The surface topography of the composite material after tribological tests was determined using scanning electron microscopy (SEM). Some of the mentioned tests were carried out on samples made only of resin, used as the matrix of the tested polymer composite. Findings: Carbon nanotubes used in polymer matrix composites, including bisphenol A/F epoxy resin have an influence on the tribological properties of the material. The addition of carbon nanotubes contributed to a 24% increase in the Ra parameter relative to pure resin, to a level corresponding to rough grinding of steel. Research limitations/implications: The results of the tests indicate the need to continue research in order to optimize the composition of composites in terms of operating parameters of friction nodes in broadly understood aviation. Originality/value: The analysed literature did not find any studies on the impact of the addition of carbon nanotubes on epoxy resins based on bisphenol A/F. Due to the wide scope of application of such resins, the properties of such composite materials in which carbon nanotubes are the reinforcing phase have been investigated.


2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 6143-6143
Author(s):  
G. C. Doolittle ◽  
A. O. Spaulding ◽  
A. R. Williams

6143 Background: The University of Kansas Medical Center (KUMC) has offered oncology services via interactive tele-video (ITV) to patients in rural Kansas for over a decade. A KUMC oncologist utilizes ITV technology to connect with patients at Hays Medical Center (HMC), which is approximately 265 west of KUMC. The technology enables the oncologist to conduct a complete patient visit without being in physical proximity to the patient. To date, two cost-tracking studies have been conducted to determine expenses associated with the tele-oncology practice. A third study recently analyzed costs incurred during fiscal year 2005 (FY05). Methods: In order to determine the costs of the practice during FY05, HMC and KUMC expenses were monitored for oncology services rendered via telemedicine. An analysis revealed expenses common to a traditional oncology practice and additional expenses unique to a telemedicine practice. Administrative support staff salaries, the oncologist’s contract fees, and nursing staff salaries made up the majority of the traditional practice-related expenses. Costs unique to a tele-oncology practice were those associated with technology including expenses for telemedicine equipment, telecommunication charges, and technician time. Results: Expenses for the tele-oncology practice on the KUMC side totaled $22,848, with $7,331 attributed to technology-related costs and $15,517 attributed to practice-related costs. For HMC, $5,803 in technology-related costs and $30,430 in practice-related costs totaled $36,233. At 235 tele-oncology consults and a combined total expense of $59,081 between KUMC and HMC, the FY05 analysis resulted in an average cost of $251 per consult. When compared to prior studies, this shows a substantial reduction in costs related to the practice of telemedicine. Conclusions: The average cost of a tele-oncology visit in Kansas has consistently decreased significantly since the practice’s 1995 inception. Analyses have revealed that the costs of providing oncology services via telemedicine are closely tied to utilization, as the majority of the expenses are related to personnel rather than technology. Telemedicine has proven itself to be a cost-efficient alternative to offering regular outreach clinics. No significant financial relationships to disclose.


Author(s):  
Salih Okur ◽  
Chun Li ◽  
Zejun Zhang ◽  
Sahi Vaidurya Pratap ◽  
Mohammed Mohammed Sarheed ◽  
...  

The Lamiaceae belong to the species-richest families of flowering plants and harbor many species used as herbs or for medicinal applications, such as Basils or Mints. Evolution of this group has been driven by chemical speciation, mainly of Volatile Organic Compounds (VOCs). The commercial use of these plants is characterized by a large extent of adulteration and surrogation. To authenticate and discern the species, is, thus, relevant for consumer safety, but usually requires cumbersome analytics, such as Gas Chromatography, often to be coupled with Mass Spectroscopy. We demon-strate here that quartz-crystal microbalance (QCM)-based electronic noses provide a very cost-efficient alternative, allowing for a fast, automated discrimination of scents emitted from leaves of different plants. To explore the range of this strategy, we used leaf material from four genera of Lamiaceae along with Lemongrass as similarly scented, but non-related outgroup. In order to unambiguously differentiate the scents from the different plants, the output of the 6 different SURMOF/QCM sensors was analyzed using machine learning (ML) methods, together with a thorough statistical analysis. The exposure and purging datasets (4 cycles) obtained from a QCM-based, low-cost homemade portable e-Nose were analyzed with Linear Discriminant Analysis (LDA) classification model. Prediction accuracies with repeating test measurements reached values of up to 90%. We show that it is not only possible to discern and identify plants on the genus level, but even to discriminate closely related sister clades within a genus (Basil), demonstrating that e-Noses are a powerful technology to safeguard consumer safety against the challenges of globalized trade.


Author(s):  
Sundaravalli Narayanaswami

This chapter is intended as an exposure to OR based methods, particularly the analytical approach to modelling railway operations. An overview of several planned operations in railway transportation is provided in an academic context. Some of the applications and the associated models are applied in realistic settings in the transportation industry, and also have demonstrated evidence of acceptance over a long number of years. Primary coverage is on transportation scheduling and the concise discussions are on planning phases, various operations that can be deterministically modeled and analysed, model development, few exercises and real-world stories, wherever appropriate. All sections are adequately provided with the list of references and an interested reader can benefit from a conceptual understanding to model development and to implement and deploy, under some prior knowledge on the basics and programming experience.


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