A Parametric Study on Free Vibration of Multi-perforated Rectangular Plates

AbstractThis work involves study of the first three natural frequencies of the perforated plates. The effect of the parameters which influence them have been studied. The parameters considered are the shape of perforations, pattern of the perforations, aspect ratio of the plate, dimensions of the plate, ligament efficiency and the mass remnant ratio (MRR). The study is focused on the effect of the most influencing parameter on the free vibrations

Capturing Skill State in Curriculum Learning for Human Skill Acquisition

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The fluid structures for soft-sphere potentials via the zero-separation theorems on molecular distribution functions

10 pags., 10 figs., 5 tabs.We present a class of closures specifically designed to satisfy the zero-separation theorems for the correlation functions y(r) (the cavity function), γ(r) = h(r) - C(r) (the indirect correlation), and B(r) (the bridge function) at coincidence r=0 for soft-sphere pair potentials. The rationale is to ensure the correct behavior of these correlation functions inside the core r<σ. Since the coincidence theorems implicate the thermodynamic properties of the bulk fluid: the isothermal compressibility, the internal energy and the chemical potentials, we can hopefully enforce consistency between the structure and thermodynamic properties. We solve the Ornstein-Zernike equation for the Lennard-Jones molecules where plentiful Monte Carlo data are available for testing. It turns out that not only consistency is achieved, we also obtain accurate structures: the pair correlation function g(r), the cavity function, and the bridge function for wide ranges of fluid states (0.72<T*<1.5, p*<0.9). Comparison with MC data attests to the accuracy. The closure of the zero-separation type (ZSEP), is sufficiently robust and flexible to ensure not only fulfillment of the zero-separation theorems but also pressure consistency. Success with the Lennard-Jones potential implies its applicability to other similar soft-sphere potentials. © 1996 American Institute of Physics.E.L. acknowledges support from the Spanish Direccion General de Investigacion Cientıfica y Tecnica under Grant No. PB94-0112

A Modular Design for Distributed Measurement of Human–Robot Interaction Forces in Wearable Devices

Measurement of interaction forces distributed across the attachment interface in wearable devices is critical for understanding ergonomic physical human–robot interaction (pHRI). The main challenges in sensorization of pHRI interfaces are (i) capturing the fine nature of force transmission from compliant human tissue onto rigid surfaces in the wearable device and (ii) utilizing a low-cost and easily implementable design that can be adapted for a variety of human interfaces. This paper addresses both challenges and presents a modular sensing panel that uses force-sensing resistors (FSRs) combined with robust electrical and mechanical integration principles that result in a reliable solution for distributed load measurement. The design is demonstrated through an upper-arm cuff, which uses 24 sensing panels, in conjunction with the Harmony exoskeleton. Validation of the design with controlled loading of the sensorized cuff proves the viability of FSRs in an interface sensing solution. Preliminary experiments with a human subject highlight the value of distributed interface force measurement in recognizing the factors that influence ergonomic pHRI and elucidating their effects. The modular design and low cost of the sensing panel lend themselves to extension of this approach for studying ergonomics in a variety of wearable applications with the goal of achieving safe, comfortable, and effective human–robot interaction

Direct amplification, sequencing and profiling of Chlamydia trachomatis strains in single and mixed infection clinical samples.

Sequencing bacterial genomes from DNA isolated directly from clinical samples offers the promise of rapid and precise acquisition of informative genetic information. In the case of Chlamydia trachomatis, direct sequencing is particularly desirable because it obviates the requirement for culture in mammalian cells, saving time, cost and the possibility of missing low abundance strains. In this proof of concept study, we developed methodology that would allow genome-scale direct sequencing, using a multiplexed microdroplet PCR enrichment technology to amplify a 100 kb region of the C. trachomatis genome with 500 1.1-1.3 kb overlapping amplicons (5-fold amplicon redundancy). We integrated comparative genomic data into a pipeline to preferentially select conserved sites for amplicon design. The 100 kb target region could be amplified from clinical samples, including remnants from diagnostics tests, originating from the cervix, urethra and urine, For rapid analysis of these data, we developed a framework for whole-genome based genotyping called binstrain. We used binstrain to estimate the proportion of SNPs originating from 14 C. trachomatis reference serotype genomes in each sample. Direct DNA sequencing methods such as the one described here may have an important role in understanding the biology of C. trachomatis mixed infections and the natural genetic variation of the species within clinically relevant ecological niches