Natural Frequency Analysis Of All Edges Clamped Flexible Thin Plate

In this paper, the analysis of natural frequencies for all clamped edges rectangular flexible thin plate is carried out using Finite Difference (FD) and Finite Element (FE) approaches. According to the literatures, the differential equation of plate was obtained by considering the Kirchhoff hypotheses and Newton’s law. The dynamic differential model is developed by using the FD to obtain the natural frequencies of given plate; for this purpose, a displacement model is converted to combination of sine and cosine functions in form of Fast Fourier Series. In second method, modes of vibration are driven by FE method using the ABAQUS software. The obtained natural frequencies of both methods are evaluated and compared with previous literatures; the outcomes can explain that the improved FD method’s results are more accurate in compare with FE method’s

Evaluation of Response Surface Designs for Simulation Experiments and the Assignment of Random Numbers to Experimental Points

Business Administratio

Diagnostic des machines dans le plan temps-fréquence

Using short-time Fourier transform in machinery fault diagnosis -- Time-frequency distributions and their application to machinery fault detection -- Application of wavelet transform in machine fault detection -- Time-frequency algorithms and their applications

Astrometric Microlensing as a Method of Discovering and Characterizing Extra-Solar Planets

We introduce a new method of searching for and characterizing extra-solar planets. We show that by monitoring the center-of-light motion of microlensing alerts using the next generation of high precision astrometric instruments the probability of detecting a planet orbiting the lens is high. We show that adding astrometric information to the photometric microlensing lightcurve greatly helps in determining the planetary mass and semi-major axis. We introduce astrometric maps as a new way for calculating astrometric motion and planet detection probabilities. Finite source effects are important for low mass planets, but even Earth mass planets can give detectable signals.Comment: 9 pages includes 8 postscript figures, AAS Latex, submitted to Ap

Fault detection and identification using Wigner-Ville distribution

Time-frequency distributions -- The application of time-frequency analysis to machinery diagnostics

Application of short-time fourier transform in machine fault detection

Time-based and frequency-based vibration analysis techniques -- Time-frequency analysis -- Applications of time-frequency analysis to machinery diagnosis

Evaluation of Radiant Heating Ceiling Based on Energy and Thermal Comfort Criteria, Part II: A Numerical Study

Large-surface radiant heating ceiling systems favor energy-efficient solutions on the heat generation side because of the relatively low temperature of the heat transfer medium. Additionally, their application in the renovation of existing buildings is relatively uncomplicated and requires minimal changes to the building’s construction. However, ASHRAE Standard-55 and former studies by Fanger indicated that among large-surface radiant systems, the highest percentage of dissatisfaction for an equal radiant temperature asymmetry (RTA) was reported for a warm ceiling. The maximum RTA of 4 K corresponding to 5% of dissatisfaction was suggested. In the first part of our study (subjective experiments), we have suggested the RTA of about 7.4 K if occupants have winter clothing (Safizadeh et al., 2018). However, former studies tested radiant ceiling systems at different temperatures in “neutral conditions” with a constant operative temperature, which rarely occurs in reality. Accordingly, the goal of this study is to evaluate the potential application of low-temperature radiant heating ceilings in a building with low- and high-performance facades using steady-state simulations with a coupled CFD–thermal comfort model and transient simulations using TRNSYS. Forty combinations of simulation scenarios including six ceiling surface temperatures (20 °C, 25 °C, 28 °C, 33 °C, 38 °C, and 45 °C), two low- and high-performance facades, two rooms with one and two facades, and distances of 1 m and 3 m to the window were examined. The findings of this research show that the supply water temperatures between 28–45 °C from a heat pump are ideal for a building with a high-performance façade. Additionally, the results suggest that ceiling temperatures as low as 20–25 °C in renovated buildings and 25–28 °C in a building with low-performance facades can provide optimal thermal sensations at most body parts. This study also proves that the PMV comfort model (Predicted Mean Vote index) is not at all a suitable model for the evaluation of radiant heating systems (especially if occupants have winter clothes), even if the air/operative temperature distribution near an occupant is uniform

Condition monitoring and diagnostic of rotating machinery by means of wavelet transforms

Wavelet transforms -- Application of the wavelet transform to machinery fault diagnosis -- Application of the wavelet transform to machinery fault diagnosis

Cutaneous Leishmaniasis in Bam: A Comparative Evaluation of Pre- and Post- Earthquake Years (1999-2008)

Background: The recent devastating earthquake of December 26 in Bam, 2003 created various risk factors; caused a sharp increase in incidence of anthroponotic cutaneous leishmaniasis (ACL) cases and reached to an epidemic proportion. The objective of this study was to evaluate the status of ACL cases five years before the earthquake compared to the cases occurred five years after the earthquake (1999-2008). Methods: Status of disease was assessed retrospectively for the five years before the earthquake and prospectively for the five years after the earthquake. Identification was confirmed by smear and polymerase chain reaction (PCR). Results: The mean annual incidence of ACL for the period from 1999 to 2003 was 1.9 per 1000 comparing to post earthquake period, which was 7.6 per 1000. Most of the infection was in individuals of <20 years, more frequently in females before the earthquake, whilst in contrast, there was a progressive rise in the number of cases, significantly in male individuals of >20 years (P< 0.0001) in post earthquake era. The anatomical distribution of lesions considerably changed during the two periods. Most of the cases were limited to three zones within the city prior to the earthquake, whereas it was spread throughout different zones after the earthquake. PCR indicated that the CL was due to Leishmania tropica in the city. Conclusion: The results strongly suggest that in natural disasters such as earthquakes various precipitating factors in favor of disease will be created, which in turn provide a suitable condition for propagation of the vector and the transmission of the parasite

High-precision astrometry on the VLT/FORS1 at time scales of few days

We investigate the accuracy of astrometric measurements with the VLT/FORS1 camera and consider potential applications. The study is based on two-epoch (2000 and 2002/2003) frame series of observations of a selected Galactic Bulge sky region that were obtained with FORS1 during four consecutive nights each. Reductions were carried out with a novel technique that eliminates atmospheric image motion and does not require a distinction between targets and reference objects. The positional astrometric precision was found to be limited only by the accuracy of the determination of the star photocentre, which is typically 200-300 microarcsec per single measurement for bright unsaturated stars B=18-19. Several statistical tests have shown that at time-scales of 1-4 nights the residual noise in measured positions is essentially a white noise with no systematic instrumental signature and no significant deviation from a Gaussian distribution. Some evidence of a good astrometric quality of the VLT for frames separated by two years has also been found. Our data show that the VLT with FORS1/2 cameras can be effectively used for astrometric observations of planetary microlensing events and other applications where a high accuracy is required, that is expected to reach 30-40 microarcsec for a series of 50 frames (one hours with R filter).Comment: 11 pages, 9 figures, accepted for publication in A&