Proučavanje strukturnih svojstava nekih jednostavnih tekućih metala u različitim referentbim sustavima

In the present paper three reference systems: Percus-Yevick hard sphere (PYHS), one component plasma (OCP) and charged hard sphere (CHS) are employed to investigate the temperature-dependent structural properties of some simple liquid metals. The structure factor S(q), pair-distribution function g (r) and interatomic distance r1 of nearest neighbour atoms for Mg, Zn, Al, In, Tl and Pb are reported. Our own model potential is employed along with the local field correction due to Sarkar et al. (SS) to describe electron-ion interaction. It is seen that the CHS method alongwith the present form of model potential can explain more accurately the structural behaviour than PYHS and OCP methods.Za istraživanje temperaturno-ovisnih svojstava strukture nekih jednostavnih tekućih metala, primijenili smo tri referentna sustava: Percus–Yevickov tvrde kugle, jednokomponentne plazme i nabijenih kuglica. Izvješćujemo o strukturnom faktoru S(q), funkciji raspodjele parova g(r) i o međuatomskim razmacima r1 najbližih atoma u Mg, Zn, Al, In, Tl i Pb. Rabimo naš vlastiti modelski potencijal i popravku lokalnog polja prema Sarkaru i sur. za opis međudjelovanja elektron-ion. Nalazimo da metoda nabijene tvrde kuglice s primijenjenim modelskim potencijalom točnije opisuje strukturna svojstva nego druge dvije metode

Proučavanje strukturnih svojstava nekih jednostavnih tekućih metala u različitim referentbim sustavima

In the present paper three reference systems: Percus-Yevick hard sphere (PYHS), one component plasma (OCP) and charged hard sphere (CHS) are employed to investigate the temperature-dependent structural properties of some simple liquid metals. The structure factor S(q), pair-distribution function g (r) and interatomic distance r1 of nearest neighbour atoms for Mg, Zn, Al, In, Tl and Pb are reported. Our own model potential is employed along with the local field correction due to Sarkar et al. (SS) to describe electron-ion interaction. It is seen that the CHS method alongwith the present form of model potential can explain more accurately the structural behaviour than PYHS and OCP methods.Za istraživanje temperaturno-ovisnih svojstava strukture nekih jednostavnih tekućih metala, primijenili smo tri referentna sustava: Percus–Yevickov tvrde kugle, jednokomponentne plazme i nabijenih kuglica. Izvješćujemo o strukturnom faktoru S(q), funkciji raspodjele parova g(r) i o međuatomskim razmacima r1 najbližih atoma u Mg, Zn, Al, In, Tl i Pb. Rabimo naš vlastiti modelski potencijal i popravku lokalnog polja prema Sarkaru i sur. za opis međudjelovanja elektron-ion. Nalazimo da metoda nabijene tvrde kuglice s primijenjenim modelskim potencijalom točnije opisuje strukturna svojstva nego druge dvije metode

But Is It Myopia? Risk Aversion and the Efficiency of Stock-Based Managerial Incentives

This paper points out that stock incentives do not lead to myopia unless they result in more emphasis on the short-term than would occur under an optimal contract. It shows that myopia findings relative to the standard used throughout the literature (first-best efficiency) are often reversed when evaluated relative to the relevant standard of optimal contracting. Results reported by the previous literature to be myopia often in fact have excessive emphasis on the long-term. The paper solves in closed-form for the region in parameter space which gives rise to these reversals and shows that it can be arbitrarily largehttp://deepblue.lib.umich.edu/bitstream/2027.42/49369/5/2008Jan16JCarmel.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/49369/1/Visiting-Carmel.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/49369/4/Visiting-Carmel.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/49369/7/1108_2008Jan16JCarmel.pd

Bearing signal separation enhancement with application to helicopter transmission system

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Bearing vibration signal separation is essential for fault detection of gearboxes, especially where the vibration is nonstationary, susceptible to background noise, and subjected to an arduous transmission path from the source to the receiver. This paper presents a methodology for improving fault detection via a series of vibration signal processing techniques, including signal separation, synchronous averaging (SA), spectral kurtosis (SK), and envelope analysis. These techniques have been tested on experimentally obtained vibration data acquired from the transmission system of a CS-29 Category A helicopter gearbox operating under different bearing damage conditions. Results showed successful enhancement of bearing fault detection on the second planetary stage of the gearbo

Underwater Leidenfrost nanochemistry for creation of size-tailored zinc peroxide cancer nanotherapeutics

The dynamic underwater chemistry seen in nature is inspiring for the next generation of eco-friendly nanochemistry. In this context, green synthesis of size-tailored nanoparticles in a facile and scalable manner via a dynamic process is an interesting challenge. Simulating the volcano-induced dynamic chemistry of the deep ocean, here we demonstrate the Leidenfrost dynamic chemistry occurring in an underwater overheated confined zone as a new tool for customized creation of nanoclusters of zinc peroxide. The hydrodynamic nature of the phenomenon ensures eruption of the nanoclusters towards a much colder region, giving rise to growth of monodisperse, size-tailored nanoclusters. Such nanoparticles are investigated in terms of their cytotoxicity on suspension and adherent cells to prove their applicability as cancer nanotherapeutics. Our research can pave the way for employment of the dynamic green nanochemistry in facile, scalable fabrication of size-tailored nanoparticles for biomedical applications.Peer reviewe

Do bad borrowers hurt good borrowers? A model of biased banking competition

This paper explores a two-bank model in which, first, one bank correctly estimates the probability of low-quality loan repayment while the other overestimates it, and second, both banks have identical convex costs when granting loans. In this context of optimistically biased banking competition, we show how the unbiased bank follows the biased competitor as long as the bias of the latter is not too large. This would favour bad borrowers, who get better credit conditions at the expense of good borrowers. As a consequence, the presence of a biased bank increases welfare as long as the expected default rate is sufficiently high. Contrariwise, in subprime markets, biased banking competition would be socially harmful.info:eu-repo/semantics/publishedVersio

Revisiting QRS detection methodologies for portable, wearable, battery-operated, and wireless ECG systems

Cardiovascular diseases are the number one cause of death worldwide. Currently, portable battery-operated systems such as mobile phones with wireless ECG sensors have the potential to be used in continuous cardiac function assessment that can be easily integrated into daily life. These portable point-of-care diagnostic systems can therefore help unveil and treat cardiovascular diseases. The basis for ECG analysis is a robust detection of the prominent QRS complex, as well as other ECG signal characteristics. However, it is not clear from the literature which ECG analysis algorithms are suited for an implementation on a mobile device. We investigate current QRS detection algorithms based on three assessment criteria: 1) robustness to noise, 2) parameter choice, and 3) numerical efficiency, in order to target a universal fast-robust detector. Furthermore, existing QRS detection algorithms may provide an acceptable solution only on small segments of ECG signals, within a certain amplitude range, or amid particular types of arrhythmia and/or noise. These issues are discussed in the context of a comparison with the most conventional algorithms, followed by future recommendations for developing reliable QRS detection schemes suitable for implementation on battery-operated mobile devices.Mohamed Elgendi, Björn Eskofier, Socrates Dokos, Derek Abbot

Planetary bearing defect detection in a commercial helicopter main gearbox with vibration and acoustic emission

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Helicopter gearboxes significantly differ from other transmission types and exhibit unique behaviors that reduce the effectiveness of traditional fault diagnostics methods. In addition, due to lack of redundancy, helicopter transmission failure can lead to catastrophic accidents. Bearing faults in helicopter gearboxes are difficult to discriminate due to the low signal to noise ratio (SNR) in the presence of gear vibration. In addition, the vibration response from the planet gear bearings must be transmitted via a time-varying path through the ring gear to externally mounted accelerometers, which cause yet further bearing vibration signal suppression. This research programme has resulted in the successful proof of concept of a broadband wireless transmission sensor that incorporates power scavenging whilst operating within a helicopter gearbox. In addition, this paper investigates the application of signal separation techniques in detection of bearing faults within the epicyclic module of a large helicopter (CS-29) main gearbox using vibration and Acoustic Emissions (AE). It compares their effectiveness for various operating conditions. Three signal processing techniques including an adaptive filter, spectral kurtosis and envelope analysis, were combined for this investigation. In addition, this research discusses the feasibility of using AE for helicopter gearbox monitoring

A brain-computer interface with vibrotactile biofeedback for haptic information

<p>Abstract</p> <p>Background</p> <p>It has been suggested that Brain-Computer Interfaces (BCI) may one day be suitable for controlling a neuroprosthesis. For closed-loop operation of BCI, a tactile feedback channel that is compatible with neuroprosthetic applications is desired. Operation of an EEG-based BCI using only <it>vibrotactile feedback</it>, a commonly used method to convey haptic senses of contact and pressure, is demonstrated with a high level of accuracy.</p> <p>Methods</p> <p>A Mu-rhythm based BCI using a motor imagery paradigm was used to control the position of a virtual cursor. The cursor position was shown visually as well as transmitted haptically by modulating the intensity of a vibrotactile stimulus to the upper limb. A total of six subjects operated the BCI in a two-stage targeting task, receiving only vibrotactile biofeedback of performance. The location of the vibration was also systematically varied between the left and right arms to investigate location-dependent effects on performance.</p> <p>Results and Conclusion</p> <p>Subjects are able to control the BCI using only vibrotactile feedback with an average accuracy of 56% and as high as 72%. These accuracies are significantly higher than the 15% predicted by random chance if the subject had no voluntary control of their Mu-rhythm. The results of this study demonstrate that vibrotactile feedback is an effective biofeedback modality to operate a BCI using motor imagery. In addition, the study shows that placement of the vibrotactile stimulation on the biceps ipsilateral or contralateral to the motor imagery introduces a significant bias in the BCI accuracy. This bias is consistent with a drop in performance generated by stimulation of the contralateral limb. Users demonstrated the capability to overcome this bias with training.</p