7,600 research outputs found

    Design and control of remote manipulators

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    Results of investigations on vibrational modes of manipulators revealed: (1) any arbitrary manipulator may be analyzed for its small motion compliances; (2) a simulation of the Martin-Marietta shuttle boom with a 65,000 lb. payload attached, indicated three natural frequencies; and (3) simulations can be made of rigid limbs and flexible joints as well as for flexible limbs and locked joints and combinations thereof. Trajectories for arms were determined so that some integral criterion such as integral of kinetic energy or control torque magnitude is minimized over a motion of the arm. Experiments performed to evaluate various TV displays in conjunction with manipulator control modes showed that when mounted directly to the manipulator control arm and arranged to look approximately along the arm to the hand the operator could perform the task almost as quickly as when viewing the task directly

    Local effects of partly-cloudy skies on solar and emitted radiation

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    A computer automated data acquisition system for atmospheric emittance, and global solar, downwelled diffuse solar, and direct solar irradiances is discussed. Hourly-integrated global solar and atmospheric emitted radiances were measured continuously from February 1981 and hourly-integrated diffuse solar and direct solar irradiances were measured continuously from October 1981. One-minute integrated data are available for each of these components from February 1982. The results of the correlation of global insolation with fractional cloud cover for the first year's data set. A February data set, composed of one-minute integrated global insolation and direct solar irradiance, cloud cover fractions, meteorological data from nearby weather stations, and GOES East satellite radiometric data, was collected to test the theoretical model of satellite radiometric data correlation and develop the cloud dependence for the local measurement site

    Local effects of partly cloudy skies on solar and emitted radiations

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    Solar radiation measurements are made on a routine basis. Global solar, atmospheric emitted, downwelled diffuse solar, and direct solar radiation measurement systems are fully operational with the first two in continuous operation. Fractional cloud cover measurements are made from GOES imagery or from ground based whole sky photographs. Normalized global solar irradiance values for partly cloudy skies were correlated to fractional cloud cover

    Inference in Linear Regression Models with Many Covariates and Heteroskedasticity

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    The linear regression model is widely used in empirical work in Economics, Statistics, and many other disciplines. Researchers often include many covariates in their linear model specification in an attempt to control for confounders. We give inference methods that allow for many covariates and heteroskedasticity. Our results are obtained using high-dimensional approximations, where the number of included covariates are allowed to grow as fast as the sample size. We find that all of the usual versions of Eicker-White heteroskedasticity consistent standard error estimators for linear models are inconsistent under this asymptotics. We then propose a new heteroskedasticity consistent standard error formula that is fully automatic and robust to both (conditional)\ heteroskedasticity of unknown form and the inclusion of possibly many covariates. We apply our findings to three settings: parametric linear models with many covariates, linear panel models with many fixed effects, and semiparametric semi-linear models with many technical regressors. Simulation evidence consistent with our theoretical results is also provided. The proposed methods are also illustrated with an empirical application

    Final Report: Wall Effects in Cavity Flows

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    The wall effects in cavity flows past an arbitrary two-dimensional body is investigated for both pure-drag and lifting cases based on an inviscid nonlinear flow theory. The over-all features of various theoretical flow models for inviscid cavity flows under the wall effects are discussed from the general momentum consideration in comparison with typical viscous, incompressible wake flows in a channel. In the case of pure drag cavity flows, three theoretical models in common use, namely, the open-wake, Riabouchinsky and re-entrant jet models, are applied to evaluate the solution. Methods of numerical computation are discussed for bodies of arbitrary shape, and are carried out in detail for wedges of all angles. The final numerical results are compared between the different flow models, and the differences pointed out. Further analysis of the results has led to development of several useful formulas for correcting the wall effect. In the lifting flow case, the wall effect on the pressure and hydrodynamic forces acting on arbitrary body is formulated for the choked cavity flow in a closed water tunnel of arbitrary shape, and computed for the flat plate with a finite cavity in a straight tunnel

    A Study of the Use of a Local Fly Ash in Concrete Mixes

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    The widespread use of powdered coal in industrial furnaces has, since its introduction in the 1930\u27s, produced considerable increases in efficiency for many industrial processes. In its wake, however, it has brought its own unique problems, and chief among these has been the problem of collecting and disposing of the residue which results from the combustion of the powdered or ground coal. This residue, known commonly as fly ash, is a nuisance if it is allowed to be dispersed into the atmosphere; and if collected it presents a difficult disposal problem. In present industrial practice it is almost always collected, either with electrostatic precipitators or cyclone separators, and deposited in ever-growing disposal dumps. A recent estimate (20)* gives the imposing figure of six million tons as the annual U.S. production of this waste product

    Screening for Alcohol use/abuse in the Primary Care Setting using the AUDIT-C and SBIRT (Screening, Brief Intervention, Referral to Treatment)

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    PURPOSE: The purpose of this study was to examine the feasibility of alcohol screening in the primary care setting to detect alcohol abuse or misuse using the AUDIT-C standardized screening tool and SBIRT. METHODS: This study design was a Quasi-Experimental intervention, one group post-test. Data was collected via retrospective chart review from the electronic medical records by the type of office visit; either new patient initial visit or annual well visit. The patient sample consisted of 25 participants for the study period of September 19th through October 10th, 2017. RESULTS: There were 37 patients eligible to participate in the study; annual visits or new patients. Two APRN providers tested the feasibility of using the tool. Of the 37 patients, 25 (n=25) received the AUDIT-C tool, and 23 scores were documented by the provider. Provider compliance in documenting was 92%. The sample was 80% female the mean age was 42.6. Almost nine percent scored high enough for a Brief Intervention. CONCLUSION: Feasibility of the AUDIT-C use in the primary care setting was shown. Providers were satisfied and felt they took away essential information they would not have otherwise had. More studies need to be done on a larger scale, incorporating more providers and more locations
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