Introduction Long-haul dump (LHD) vehicles used in underground mining are known to expose workers to important levels of whole-body vibration. These vehicles are generally designed without suspension and may be categorized as small or large LHDs depending on whether their respective load capacities are lower or larger than 3.5 cubic yards. While the majority of older vehicles are equipped with ...

Abstract Elastic mechanical metamaterials are the exemplar of periodic structures. These artificially designed structures having idiosyncratic physical properties like negative mass and Young’s modulus in specific frequency ranges. extreme due to spatial periodicity unit cells, which exhibit local resonance. That is why scientists researching dynamics these for decades. This unusual dynamic beh...

Tunnels are commonly excavated using drilling and blasting methods, the surrounding rock is greatly affected by vibration of hole blasting. To study influence number free surfaces on energy distribution attenuation law signals, on-site experiments numerical simulation were conducted. The research results indicate that higher surfaces, smaller peak velocity. longitudinal Fourier main frequency d...

This research investigates a concept for cut-out resonators that exploit small area of active mass host plate structure sake tuned, low frequency vibration attenuation. Integrated computational and experimental studies reveal embedding the at locations offering high bending moment gradient arranging central resonator beam along nodal line best excite first eigenmode targeted suppression. These ...

SPECT detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. Attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. In our study efficacy of Chang method was evaluated for attenuation purpose, using a custom made heart phantom. Due to d...

  Introduction: Attenuation correction is a useful process for improving myocardial perfusion SPECT and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). Attenuation artifacts are a common problem in myocardial perfusion SPECT. The aim of this study was to compare the effect of attenuation correction using different a...

seismic refraction and downhole survey were employed to study dynamic characteristics of subsurface materials in bam city, southeast of iran. the data acquisition was performed at 160 p and s-wave refraction stations and 15 boreholes in the city. to derive velocity depth sections along these profiles as well as to perform downhole diagrams, seisimager software was used. based on the obtained va...

The vibro-acoustic performance of a fluid-loaded periodic locally resonant (LR) plate was examined in this research, with specific focus on the effect water fluid vibration and sound radiation LR structure. analytical models plate’s band gap, vibration, acoustic were theoretically derived closed-form solutions, which can be used to predict general rules underwater results show that band-gap wid...

The purpose of present study was to compare the effect of Ia afferent attenuation on the activity of alpha motor neuron (MN) during concentric and eccentric action. Eight male subjects were enrolled in the present study. The experiments consisted of two sessions of MVC measurements, since all subjects performed both maximal concentric and eccentric action. EMG signals were simultaneously measur...

Metamaterials have been the subject of significant interest over the past decade due to their ability to produce novel acoustic behaviour beyond that seen in naturally occurring media. As well as their potential in acoustic cloaks and lenses, of particular interest is the appearance of band gaps which lead to very high levels of attenuation across the material within narrow frequency ranges. Un...