7,100 research outputs found

    The effects of load and gradient on hand force responses during dynamic pushing and pulling tasks

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    The limited attention afforded to push/pull activities and the motion phases (initial, sustained and ending) characteristic of these tasks has prompted a research focus in this area. The present study examined biomechanical responses in the form of hand forces during dynamic submaximal trolley pushing and pulling. Participants pushed/pulled loads of 100, 200 and 300 kg on the level (determining impact of load) or pushed 100 kg along a 12° ramp (uphill and downhill- determining impact of gradient). During level exertions significant differences (p<0.05) in hand forces occurred between loads of 100 and 200 kg, and 100 and 300 kg for initial and sustained forces but not ending forces. Values were similar for pushing and pulling at respective loads and motion phases. Strong correlations indicate that initial forces can be used to accurately estimate sustained and ending forces. Importantly, correct technique is essential in force reduction. Forces were highest during uphill initial and sustained phases and the downhill sustained phase. For the initial phase, the forces were highest during uphill pushing (86.5 ± 25.73 N); for the sustained phase, there was no difference between uphill and downhill forces but level forces were significantly lower (18.19 ± 8.09 N) than either of the other two conditions; for the ending phase, the highest forces were produced during downhill pushing (-53.34 ± 13.65N). As sustained forces equaled or exceeded initial forces for uphill and downhill efforts, consideration of sustained forces may be appropriate in determining the inherent potential risk of graded pushing

    A case of inferior lumbar hernia

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    In this article we report a case of inferior lumbar hernia. The patient underwent preperitoneal meshplasty. The patient is well on follow up with no recurrence. The relevant literature has been reviewed and management discussed in brief

    Science Validation of the Spitzer Source List

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    The Spitzer Science Center will produce a source list (SL) of photometry for a large subset of imaging data in the Spitzer Heritage Archive (SHA). The list will enable a large range of science projects. The primary requirement on the SL is very high reliability — with areal coverage, completeness and limiting depth being secondary considerations. The SHA at the NASA Infrared Science Archive (IRSA) will serve the SL as an enhanced data product. The SL will include data from the four channels of IRAC (3–8 microns) and the 24 micron channel of MIPS. The Source List will include image products (mosaics) and photometric data for Spitzer observations of about 1500 square degrees and include around 30 million sources. We describe ongoing science validation of the Spitzer Source List, and discuss the range of use cases which will be supported

    Infrared luminosities of galaxies in the Local Volume

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    Near-infrared properties of 451 galaxies with distances D \leq 10 Mpc are considered basing on the all-sky two micron survey (2MASS). A luminosity function of the galaxies in the K-band is derived within [-25,-11] mag. The local (D < 8 Mpc) luminosity density is estimated to be 6.8*10^8 L_sun/Mpc^3 that exceeds (1.5+-0.1) times the global cosmic density in the K-band. Virial mass-to-K-luminosity ratios are determined for nearby groups and clusters. In the luminosity range of (5*10^{10} - 2*10^{13})L_sun, the groups and clusters follow the relation \lg(M/L_K) propto (0.27+-0.03) lg(L_K) with a scatter of \~0.1 comparable to errors of the observables. The mean ratio ~= (20-25) M_sun/L_sun for the galaxy systems turns out to be significantly lower than the global ratio, (80-90)M_sun/L_sun, expected in the standard cosmological model with the matter density of Omega_m =0.27. This discrepancy can be resolved if most of dark matter in the universe is not associated with galaxies and their systems.Comment: 15 pages, 7 figures. Astronomy Letters, submitte

    Static & Thermal Analysis of Piston for Single Cylinder Diesel Engine by Ansys : A Review

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    The main objective of this present research work is to investigate and analyze the stresses which are acting on the piston. The parameter which is used for analysis is temperature, operating pressure and properties of materials. Piston in internal combustion engine play most important role because it transfers the force which is produced during the combustion of fuel to crankshaft due to which it converts the pressure energy into mechanical energy. Piston fails due to thermal and mechanical stresses which are produced under the running condition of engine. The boundary conditions are applied for static and thermal analysis which includes pressure on piston head during working period and uneven temperature distributions occurs from head of piston to skirt of piston. The 3D-model will be created using SOLIDWORKS2018.the 3D model will be imported in the Ansys software for geometry and meshing purposes then the FEM Analysis will be done on ANSYS software. Analysis will help to change the existing design for reduce the weight. Finite Element Analysis is the best method for analyzing the stresses in piston

    Isolated bilateral simplex ureteric ectopia: Bladder capacity as an indicator of continence outcome

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    INTRODUCTION: Isolated bilateral simplex ectopic ureters (BSEUs) are rare but pose a therapeutic challenge: ureteric reimplantation alone does not accomplish continence in all. Identifying the patients needing additional procedures for continence early could prevent multiple operations. OBJECTIVE: Potential preoperative indicators for postoperative continence are explored in eight BSEU girls without cloacal, anorectal, or spinal anomalies. STUDY DESIGN: With institutional approval, all patients with BSEU between 1985 and 2012 were retrospectively reviewed. Cystoscopy determined the site of ureteric ectopia (6 of 16 at the bladder neck [BN], 5 of 16 below the BN, and 5 of 16 in the distal urethra). Bladders were assessed by a combination of ultrasound, urodynamics, micturating cystourethrogram, cystoscopic, and intraoperative observations. Expected bladder capacity for age (EBCA) was calculated by 30 ml + (30 ml × age in years) or 38 ml + (2.5 ml × age in months) for children greater or less than 2 years, respectively. Continence outcomes were appraised at a minimum of 4 years. The small number of patients precludes credible statistical analysis and therefore raw data are presented. RESULTS: Patients underwent cross-trigonal ureteric reimplantation at 1–5.5 years, in five without BN surgery and in three with a Young–Dees–Leadbetter BN tightening. Of those without BN surgery at reimplantation, four achieved satisfactory continence for their age, but one has had multiple procedures culminating in BN closure, ileocystoplasty, and Mitrofanoff. Among the BN-tightening group, one was in nappies at 4 years, one had residual stress incontinence after two further BN injections, and one proceeded to artificial urinary sphincter after two BN injections. Five patients had significant renal impairment. DISCUSSION: Patients with satisfactory continence after reimplantation alone and those needing further procedures tended to differ in their preoperative observations of bladder capacity and apparent BN competence. This study suggests preoperative observations of an empty bladder on serial ultrasound and/or a wide-open BN with small or even moderate bladder capacity at cystoscopy to indicate the need for BN surgery. In contrast, children with bladder filling to at least 30% of expected bladder capacity for age on preoperative ultrasound or apposition of the BN at cystoscopy may achieve satisfactory continence after ureteric reimplantation alone. Bladder capacity as an indicator of BN competence can also be correlated to continence outcomes in previously published series. Polyuria associated with renal impairment can exacerbate the challenge for continence. CONCLUSION: Preoperative bladder capacity appears to be an indicator of inherent BN function and a thorough assessment of the urinary tract by cystoscopy, ultrasound, micturating cystourethrogram, and functional imaging may guide the surgeon on the need for BN surgery at the time of ureteric reimplantation. Where continence remains elusive, patients should be counselled that a further BN injection is occasionally of value although more significant BN procedures are required for most

    PAH Emission from Ultraluminous Infrared Galaxies

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    We explore the relationships between the Polycyclic Aromatic Hydrocarbon (PAH) feature strengths, mid-infrared continuum luminosities, far-infrared spectral slopes, optical spectroscopic classifications, and silicate optical depths within a sample of 107 ULIRGs observed with the Infrared Spectrograph on the Spitzer Space Telescope. The detected 6.2 micron PAH equivalent widths (EQWs) in the sample span more than two orders of magnitude (0.006-0.8 micron), and ULIRGs with HII-like optical spectra or steep far-infrared spectral slopes (S_{25} / S_{60} < 0.2) typically have 6.2 micron PAH EQWs that are half that of lower-luminosity starbursts. A significant fraction (~40-60%) of HII-like, LINER-like, and cold ULIRGs have very weak PAH EQWs. Many of these ULIRGs also have large (tau_{9.7} > 2.3) silicate optical depths. The far-infrared spectral slope is strongly correlated with PAH EQW, but not with silicate optical depth. In addition, the PAH EQW decreases with increasing rest-frame 24 micron luminosity. We argue that this trend results primarily from dilution of the PAH EQW by continuum emission from dust heated by a compact central source, probably an AGN. High luminosity, high-redshift sources studied with Spitzer appear to have a much larger range in PAH EQW than seen in local ULIRGs, which is consistent with extremely luminous starburst systems being absent at low redshift, but present at early epochs.Comment: 15 pages, 9 Figures; Accepted for publication in Ap

    HST Morphologies of z~2 Dust Obscured Galaxies I: Power-law Sources

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    We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24um--bright z~2 Dust Obscured Galaxies (DOGs) identified in the Bootes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V-H and I-H colors of the extended components are 0.2-3 magnitudes redder than normal star-forming galaxies. All but 1 have axial ratios >0.3, making it unlikely that DOGs are composed of an edge-on star-forming disk. We model the spatially extended component of the surface brightness distributions of the DOGs with a Sersic profile and find effective radii of 1-6 kpc. This sample of DOGs is smaller than most sub-millimeter galaxies (SMGs), but larger than quiescent high-redshift galaxies. Non-parametric measures (Gini and M20) of DOG morphologies suggest that these galaxies are more dynamically relaxed than local ULIRGs. We estimate lower limits to the stellar masses of DOGs based on the rest-frame optical photometry and find that these range from ~10^(9-11) M_sun. If major mergers are the progenitors of DOGs, then these observations suggest that DOGs may represent a post-merger evolutionary stage.Comment: 23 pages, 9 figures, 6 tables, accepted to ApJ; lower limits on stellar mass revised upwards by factor of (1+z

    How efficient are coronal mass ejections at accelerating solar energetic particles?

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    The largest solar energetic particle (SEP) events are thought to be due to particle acceleration at a shock driven by a fast coronal mass ejection (CME). We investigate the efficiency of this process by comparing the total energy content of energetic particles with the kinetic energy of the associated CMEs. The energy content of 23 large SEP events from 1998 through 2003 is estimated based on data from ACE, GOES, and SAMPEX, and interpreted using the results of particle transport simulations and inferred longitude distributions. CME data for these events are obtained from SOHO. When compared to the estimated kinetic energy of the associated coronal mass ejections (CMEs), it is found that large SEP events can extract ~10% or more of the CME kinetic energy. The largest SEP events appear to require massive, very energetic CMEs

    The design of education in 'Manufacturing Quality Management' to enable quantifiable industrial improvements by students

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    Degree apprentices (DAs) undertake an exciting, alternative route to academic qualifications, combining real employment with University study. Here, we discuss their education in ‘Quality Improvement’ at WMG, focusing on the development of statistical expertise in Year 2 of their programme to procure real improvements in manufacturing and service operations. We show how the preparation for these in Year 1 and the further extension of these in Year 3, interleaved with work-based projects, ensure that DAs can make a significant impact during their apprenticeships. This provides a rapid return on investment for employers, and recognition and faster career progression for DAs
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