Increasing Load (increasing + load)

Distribution by Scientific Domains

Selected Abstracts

Reactivity of alkylated phosphorothionates with steel: a tribological and surface-analytical study

Roman Heuberger
Abstract Phosphorothionates are anti-wear lubricant additives and potential replacements for zinc dialkyldithiophosphates. In this study, ball-on-disc tests have been carried out combinatorially under extreme pressure (EP) conditions (100,350,MPa at 10,N load). The tests were performed in oil containing triphenyl phosphorothionates substituted with alkyl chains of different lengths. Imaging, small-area and angle-resolved X-ray photoelectron spectroscopy were performed following the tribotest to probe the modification, removal and growth of the surface film. The films were composed, depending on the test conditions, of (i) iron phosphate, (ii) iron phosphates with sulphates or (iii) a mixture of iron phosphates with sulphides and sulphates. With increasing load, the dimensional wear coefficients decreased. Upon increasing temperature from 30 to 150°C, the wear became more severe. These findings suggest the formation of a tribochemical film with some EP performance, despite the severe tribological test conditions applied in this work. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Evaluation of Adhesion and Wear Resistance of DLC Films Deposited by Various Methods

Takahiro Horiuchi
Abstract Diamond-like carbon (DLC) coatings are currently being used in a wide variety of industrial fields because of their outstanding properties, such as high hardness and low friction coefficient, among others. DLC coatings have various characteristics depending on the deposition method used. However, they have a problem regarding adhesion with the base material, which is a major factor hindering their expanded application in other fields. The adhesion of DLC coatings is generally evaluated using Rockwell indentation tests and scratch tests. These test methods induce damage in the specimen with the application of a single load. Accordingly, there is a problem of low correlation between such test results and evaluations of the adhesion of coatings on actual components that undergo repeated sliding cycles. With the aim of resolving that problem, this study evaluated the damage condition of three types of DLC coatings having different physical properties using newly devised cyclic sliding test methods involving the application of a continuously increasing load. The evaluation results obtained with these new methods differed from the results of Rockwell tests and scratch tests. These new test methods are more able to reproduce the damage done to DLC coatings in actual sliding cycles. This paper describes the test procedures and the evaluation results obtained. [source]

Microvascular lesions in the brain and retina: The age, gene/environment susceptibility,Reykjavik study,

Chengxuan Qiu MD
Objective To investigate whether the severity and location of cerebral white matter hyperintensities (WMHs) and brain infarcts are correlated with the signs of retinal microvascular abnormalities in the elderly. Methods The study included 4,176 men and women (mean age, 76 years) who participated in the Age, Gene/Environment Susceptibility (AGES),Reykjavik Study. Digital retinal images of both dilated eyes were taken and evaluated for the presence of retinal focal arteriolar signs (focal arteriolar narrowing and arteriovenous nicking) and retinopathy lesions (retinal blot hemorrhages and microaneurysms). Brain magnetic resonance imaging scans were acquired and evaluated for the presence and distribution of cerebral infarcts and WMHs. Logistic and multinomial logistic models were constructed to estimate the association of retinal microvascular signs to brain lesions. Results Controlling for demographic and major cardiovascular risk factors, we found that retinal focal arteriolar signs, but not retinopathy lesions, were significantly associated with an increasing load of subcortical and periventricular WMHs. The strongest association was found between retinal arteriolar signs and a heavier WMH load, specifically in the subcortical frontal lobe, and periventricular frontal and parietal caps. There was a tendency toward bilateral retinal focal arteriolar narrowing being more strongly associated with the heavier load of subcortical WMHs. Arteriovenous nicking was significantly associated with subcortical infarcts. Interpretation In older adults, retinal focal arteriolar signs, but not retinopathy lesions, are correlated with the load of diffuse WMHs, particularly those located in the subcortical frontal lobe, and the periventricular frontal and parietal caps of the brain. Ann Neurol 2009;65:569,576 [source]

Bauwerks-Management-System (BMS) , Werkzeug zur Substanzerhaltung für Verkehrsbauwerke

BAUTECHNIK, Issue 10 2004
Peter Haardt Dr.-Ing.
Das Bundesfernstraßennetz beinhaltet eine große Anzahl von Brücken und anderen Ingenieurbauwerken, wie Tunnel, Lärmschutzeinrichtungen und Stützwände. Die für diese Bauwerke aufzustellenden Erhaltungsprogramme erfordern nicht nur erhebliche Geldmittel, sondern beeinflussen auch Wirtschaft und Gesellschaft insgesamt. Neben den ständig wachsenden Verkehrsbeanspruchungen zwingen die ungünstiger werdende Altersstruktur und der wirtschaftliche Einsatz der zur Verfügung stehenden Haushaltsmittel alle Beteiligten dazu, die Erhaltung der Bundesfernstraßen zu systematisieren, um auch zukünftig den Verkehrsteilnehmern eine ausreichende Qualität der Verkehrswege zu sichern. Diese Aufgabe wird durch die Anwendung eines umfassenden Management Systems (Bauwerks-Management-System, BMS) unterstützt und erleichtert. Das BMVBW realisiert ein umfassendes Bauwerks-Management-System mit Teil modulen für Bundes- und Länderverwaltungen, welches als Hilfsmittel für die Erstellung von Erhaltungsplanungen dient und als Controlling-Instrument die Realisierung von Zielen und Strategien ermöglicht. Angestrebt werden damit eine bundesweite Vereinheitlichung von Planungsverfahren sowie die Verbesserung der Wirtschaftlichkeit im Rahmen der Erhaltung der Bauwerke des Bundesfernstraßennetzes. Der Beitrag beschreibt neben den bereits existierenden Regelungen und Verfahren die aktuellen Entwicklungen von Verfahren zur Unterstützung der Erhaltungsplanungen, die derzeit für Computeranwendungen bereitgestellt werden. Wesentliche Einzelthemen sind Informationsbereitstellung, Entwicklung von Erhaltungsstrategien und Bewertungsverfahren auf Objekt- und Netzebene. Bridge Management System (BMS) , a tool for maintenance of highway structures. The federal road network of Germany contains a large number of highway structures like bridges, tunnels, retaining walls and others. The maintenance programs to be prepared for this purpose not only require a high budget, but also influence the economy and society as a whole. Due to growing volumes of traffic and higher weights of trucks, bridges are subjected to increasing loads which implies that maintenance costs will be rising in the future. Considering the fact that financial resources become continuously tighter, the maintenance costs have to be spent in a way to obtain the greatest possible benefits. This task will in the future be supported by the application of individual computer programs in the frame of a comprehensive Management System (Bridge Management System, BMS). Firstly, the BMS is to provide the Federal Ministry with an overview of the current situation at the overall network level, and allow it to come to financial requirements as well as strategies for realising long-term objectives. Secondly, the states and authorities are to be supplied with recommendations for performing improvements at the object level and the state network level in compliance with given strategies and budgetary restrictions. The paper describes the existing regulations as well as procedures for the support of maintenance planning which are currently being developed for computer application. Important topics are information technology, development of maintenance strategies and assessment procedures on object and network level. [source]