Sökresultat

Wear particles originating from disc brakes contribute to particulate concentration in the urban atmosphere. In this work novel nanoporous composite-based and conventional brake materials were tested against cast-iron discs in a modified pin-on-disc machine. During testing airborne wear particles were measured online and collected on filters, which were analysed using SEM and EDX. The morphology o

Since brake wear is an important contributor to the concentration of airborne particles in urban atmospheres, it is important to increase our understanding of the origin of these particles. The contact situation between the pad and disc is complicated. Metal fibres in the pad (or other hard materials) form stable contact plateaus, which carry the main part of the load. A flow of wear particles in

Much attention is given to the consequences of airborne particles on human health and well-being. Wear is one source of airborne particles and contributions in the urban environments from wheel-to-rail contacts and disc brakes cannot be neglected. Traditionally, mechanical wear has been associated with the generation of particles of diameters of some microns. However, the research described has fo

During braking, both the rotor and pads experience wear, generating particles that may become airborne. In field tests, it is difficult to distinguish these particles from others in the surrounding environment, so it is preferable to use laboratory test stands to study the amount of airborne wear particles generated. The purpose of this work is to investigate the possibility of separate, capture,

Most modern passenger cars have disc brakes on the front wheels. Unlike drum brakes, disc brakes are not sealed off from the ambient air. During braking, both the rotor and the pads wear, and this wear process generates particles that may become airborne. In field tests it is difficult to distinguish these particles from others in the environment. It is thus preferable to conduct tests using labor

A novel test method was used to study the concentration and size distribution of airborne wear particles from disc brake materials. A pin-on-disc tribometer equipped with particle counting instruments was used as test equipment. Material from four different non-asbestos organic (NAO) pads and four different low metallic (LM) pads were tested against material from grey cast iron rotors. The results

Unga forskare som vill göra akademisk karriär står inför många utmaningar. Deras tillvaro präglas av osäkra anställningar, motstridiga krav och begränsade erfarenheter av att stå på egna ben. Många befinner sig dessutom i familjebildande ålder. Kunskap om hur man kan göra för att må bra och nå framgång på sina egna villkor är sällsynt – få forskare låter andra få en inblick i deras forskartillvaro

During braking, both the rotor and the pads are worn in disc brakes. This wear process generates particles which may become airborne. In passenger car field tests it is difficult to distinguish these particles from others in the surrounding environment. It may therefore be preferable to use laboratory test stands and/or simulation models to study the amount of airborne wear particles generated. Th

During braking, there is wear on both the rotor and the pads. This process generates particles that may become airborne. In fi eld tests, it is diffi cult to distinguish these particles from others in the surrounding environment. Therefore, a laboratory test stand has been designed which allows control of the cleanliness of the surrounding air. The test stand consists of a front right brake assemb

Prospects to use III-V technology to increase the performance of key millimeter wave circuits are discussed. We use 60 GHz wavelet generators to form coherent pulses with controllable pulse lengths down to 25 ps under low-power operation. The transmitters are used to demonstrate transmission at high data rates and very low bit-error-rates with simple modulation schemes (OOK) in direct links over s

This article explores four preselected permanent magnet synchronous machine (PMSM) topologies suitable for direct mounting on low pressure spool in a turbo fan engine. The challenge of contributing to More Electric Engine (MEE) development is that the electrical machine needs to operate over wide speed range, take advantage of available space that forces to use a high number of poles and last but

Large intelligent surface (LIS) is a new technology yet to be developed. However, this technology is likely to be implemented using cheap components so as to facilitate its deployment. Therefore, we can expect a performance degradation due to hardware impairments. In this paper, we present a model for these hardware impairments in a receiving LIS and we analyze their effect on the achievable rate

In this paper, we generalize the one-bit quantized low resolution RELAX algorithm to allow for exponentially decaying modes. The resulting greedy algorithm exploits a time-varying threshold to allow for the estimation of the parameters detailing the modes. The improvement offered by the proposed algorithm as compared to its predecessor, and the corresponding Cramér-Rao Lower Bound, is illustrated

The activation of the kallikrein-kinin system is thought to be one of the pathophysiologic mechanisms in acute pancreatitis. A radioimmunoassay for human urinary tissue kallikrein was developed and used to measure tissue kallikrein peritoneal exudate and plasma from 48 patients with severe acute pancreatitis. All patients were treated with intraperitoneal lavage. One group (n = 22) received high d

The elimination of radio-iodinated porcine tissue kallikrein, after intravenous injection in the pig, showed a rapid initial clearance from plasma (T1/2 approximately 10min), followed by a phase of slower elimination (T1/2 approximately 100min). Gel filtration of plasma samples showed complexes with alpha1-alpha2-macroglobulin (A1a2-M) and alpha1-proteinase inhibitor (A1PI), which decreased with t

In this work, we consider the problem of estimating the parameters of polynomially damped sinusoidal signals, commonly encountered in, for instance, spectroscopy. Generally, finding the parameter values of such signals constitutes a high-dimensional problem, often further complicated by not knowing the number of signal components or their specific signal structures. In order to alleviate the compu

The activation of the kallikrein-kinin system is thought to be one of the pathophysiological factors in acute pancreatitis. A radioimmunoassay for porcine, pancreatic tissue kallikrein was developed and used to measure levels in normal plasma and peritoneal fluid and in experimental, bile-induced (group A) and bile trypsin-induced (group B) acute pancreatitis in the pig. Normal porcine plasma and

This paper investigates a new regularization of the group-sparsity estimation problem based on a quadratic envelope operator. The resulting estimator is shown to have a reduced bias when compared to the classical LASSO estimator and is characterized by a simple hyperparameter selection. Numerical results show that the quadratic envelope regularization yields estimates equal to an oracle solution w

Supermassive black holes are found in most galactic nuclei. A large fraction of these nuclei also contain a nuclear stellar cluster surrounding the black hole. Here we consider the idea that the nuclear stellar cluster formed first and that the supermassive black hole grew later. In particular we consider the merger of three stellar clusters to form a nuclear stellar cluster, where some of these c