State, citizenship, and common good: British idealists' influence on social philosophy and planning culture

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Test rig for friction force measuremets in pneumatic components and seals

This article describes the design of a new test rig for measuring the friction force in pneumatic components and seals. The test rig was designed in order to measure both the overall friction force in a pneumatic cylinder or a valve as a whole, and the single contribution to friction force caused by the sliding seals. To this end, special fixtures and devices were designed and manufactured in order to measure the friction force in piston seals, rod seals and cartridge valve seals individually. Results of friction measurements carried out on pneumatic cylinders with similar characteristics but produced by different manufacturers are presented and compared. A test procedure and a methodology, in order to separate the contributions of the individual seals from the overall friction of the cylinders, is presented

Experimental analysis and preliminary model of non-conventional lip seals

The paper describes the tests carried out to determine the applicability of a simple means for reducing friction force in linear pneumatic actuators. The idea is based on the use of commercial lip seals mounted in the direction opposite to that used in conventional systems. Two different non-conventional installations were tested using commercial spring-energized seals consisting of two different materials: virgin PTFE and graphite-filled PTFE. Tests assessed the effect of bore manufacturing tolerances with nominal bore diameters of 50.0 mm and 50.2 mm. Performance was evaluated in terms of leakage flow rate and friction force, comparing the proposed installation with conventionally mounted seals. Friction coefficient and stiffness of the two seal materials were measured on a seal segment mounted on a pin-on-disk tribometer featuring a special pin design. Tests were carried out by loading the seal segment against a portion of the cylinder barrel in reciprocating motion. Stiffness and friction coefficient measurements served as the basis for developing a preliminary lumped parameter model of the lip seal which was used to analyze lip deflections, exchanged forces and leakage flow rate between seal and barrel

Non-conventional lip seal mountings for pneumatic cylinders

Sliding lip seals are used in pneumatic cylinders to prevent leakage past the piston and rod. Though they guarantee excellent sealing, the friction forces at contact between lip and counterpart can be relatively high. This results in energy losses and problems with wear on components in relative motion, as well as difficulties in controlling actuator positioning. Standards for compressed air cleanliness restrict the use of greases and lubricants, especially in applications such as the food processing and pharmaceutical industries. A number of studies are thus under way in order to find effective alternatives to the use of common lubricants. These studies address both seal configuration [1-4], and the use of innovative materials [5-7]. Other approaches employ systems permitting small amounts of air leakage that operate as lubricated supports, variable-profile pistons [8], or rings with special micromachined surfaces [9-10]. Such solutions are not always economical, both because they require precision tolerances and geometries, and because they use special seals, often produced ad hoc. This paper discusses the possibility of using commercial lip seals with a non-conventional mounting on the piston in order to obtain a simple controlled-leakage system that reduces friction forces in pneumatic cylinders economically and effectively. The non-conventional mounting consists of positioning the lip seal in the direction opposite to that used in a conventional installation, so that the contact pressure reduces as air pressure in the chamber rises. In this way, an air gap is created at the sliding interface which allows air in the pressurized chamber to escape past the seal lip, thus reducing the contact force on the barrel. The piston is provided with a hole which exhausts the leakage flow to the atmosphere. To evaluate the validity of this approach, a number of preliminary tests were carried out in [11] to measure flow rate on a type of spring-loaded lip seal consisting of graphite-filled PTFE for barrel diameters of 50 mm. In particular, the tests determined air leakage behavior for different mounting tolerances. This paper presents further tests conducted on the same samples examined in [11] and on another PTFE and graphite-filled PTFE configuration, measuring leakage flow rates and friction forces. Leakage flow rate measurements were carried out with single and double seal installations. The results obtained are discussed together with the advantages of the proposed solution compared to the conventional mountings in ordinary use

Pegylated-interferon-α(2a) in clinical practice: how to manage patients suffering from side effects

Introduction: The goal of antiviral therapy in patients with chronic hepatitis C is to slow or halt the progression of fibrosis and prevent the development of cirrhosis. Accordingly, antiviral treatment is proposed for a large population of patients with chronic hepatitis. Areas covered: The standard-of-care for chronic hepatitis C is the combination of pegylated IFN (PEG-IFN) and ribavirin. The use of these drugs has been correlated with a range of adverse effects, including influenza-like symptoms, hematological changes and neuropsychiatric disturbances. The effects of these adverse events associated with PEG-IFN therapy are manifold and are a major reason why patients decline or stop therapy. This review addresses the screening for adverse event risk factors and guides the patient to success with adherence strategies. Expert opinion: Knowledge of the side effects correlated with PEG-IFN is very relevant for clinicians because it can allow them to arrange the best methods for treating these effects and avoid the discontinuation of antiviral treatment. Moreover, the use of new antiviral drugs will considerably shorten treatment periods reducing many of the above-described side effects and, thus, increase adherence to scheduled therapy

A Novel Characterization Method for Hard Coatings: Preliminary Results with TiN

Pin-on-disc method is increasingly used to evaluate the tribological behavior of thin hard coatings. At present, ISO 18535 is the only standard applying to hard coatings tribology and it prescribes that investigations do not extend past the coating failure. This approach followed by many researchers is inadequate though for a complete characterization of a coated system. A novel approach is proposed in this paper, at a preliminary stage, to characterize coated systems thoroughly. Friction curves with a suitable shape are resorted to, so that two representative friction coefficients can be extracted, one before and the other after coating failure. Results with a PVD TiN coating are presented showing that it is possible with this coating to get friction curves with the desired shape in specific testing conditions

Handbooks in planning: five theses for teaching across national borders

Handbooks are assigned the task of presenting knowledge in a systematic manner for practical learning purposes. This is less immediate for spatial planning, a complex (and sometimes confusing) field of knowledge, also because of the different legal frameworks and cultural traditions in which it is practiced. Handbooks in planning are indeed used to refer the teaching to a specific national context, but this may lead to confusing the technical nature of planning with its institutional codification. The handbook recently published by the present authors in Italy builds on the assumption that planning education requires, first and foremost, that students understand its value as specific technical knowledge. From this assumption follows the distinction between ‘spatial governance’ and ‘spatial planning’, adopted in the handbook. The proposed contribution summarises the educational choices behind the handbook in five theses, which are discussed as a basis for teaching planning in an international perspective: 1) urban planning is a field of knowledge, teaching its technical aspects means teaching spatial planning; 2) to teach spatial planning we must explain why it is instrumental for the purposes of spatial governance; 3) the technique of spatial planning originated from recognisable matrices, the teaching of which lays the foundations for all subsequent learning; 4) also for teaching purposes, the technique of spatial planning can be traced back to zoning; 5) spatial governance is not a form of technical knowledge, but a political practice that may be taught insofar as it is necessary for understanding the effects of spatial planning

Dorsal Prefrontal Cortex Impairment in Methoxetamine-Induced Psychosis: an 18F-FDG PET/CT Case Study

Submitted15 June 2018. Accepted 13 December 2018. Epub ahead of print 13 February 2019Novel psychoactive substances (NPSs) have currently become a major public health concern because of relatively easy accessibility to these compounds and difficulty in identifying them with routine laboratory techniques. Here, we report the 18 F-fluorodeoxyglucose positron emission tomography/computerized tomography ( 18 F-FDG PET/CT) case study of a 23-year-old man who developed a substance-induced psychotic disorder after having intravenously injected himself with an unspecified amount of methoxetamine (MXE), a ketamine derivative hallucinogen. From a clinical perspective, a blunted affective responsiveness with diminished social drive and sense of purpose, along with a profound detachment from the environment, was observed. Psychometric and neuropsychological assessments highlighted severe dissociative symptoms and lack of motivation, along with a mild impairment of verbal fluency, working memory, and attention. Patient’s 18 F-FDG PET/CT scans displayed a significant bilateral deficit of tracer uptake within the dorsolateral prefrontal cortex (DLPFC). DLPFC activity is critical to goal-oriented cognitive functions, including working memory and sustained attention. DLPFC is also involved in both the temporal integration across multiple sensory modes and in the volitional control of actions, leading to the possibility to construct logically coherent temporal configurations of thought, speech, and behavior. This report highlights that a single acute MXE intoxication may produce severe brain impairment.Peer reviewedFinal Accepted Versio

An early method for the technical diagnosis of pin-on-disk tribometers by reference friction measurements in EHL conditions

Reference tests are widely used to calibrate scientific instruments but are potential candidate to establish technical diagnosis procedures for scientific instruments too. A reference test is currently lacking in tribology. Though, it would allow users to check that tribometers are properly working and may also form a yardstick for cross-laboratory comparative studies. In this paper two easy-to-use reference testing procedures for the diagnosis of commercial pin-on-disc tribometers are established resorting to a special no-wear test setup in EHL conditions. Several tests were carried out with two tribometers and two commercial oils, and both standardized testing modes were investigated: unidirectional-rotating and linear-reciprocating mode. The friction curves from more than 350 tests were analyzed to generate meaningful statistics supporting the robustness of these procedures. The test setup proved to be suited to the task since the summary of the results showed an excellent repeatability of friction curves concerning appearance and average values