The use of hydraulic models in the design of suspended-load samplers

The amount of suspended solid material transported by a stream is usually determined by making measurements of sediment-content and of velocity at many points in the cross-section and integrating the results. The number of sampling points required will depend upon the degree of accuracy necessary, and, according to O'Brien [see 1 of “References” at end of paper], upon our knowledge of turbulent flow and its relation to sediment-transportation. The suspended-load samplers used for these measurements may be divided into two classifications, depending upon the length of the sampling period. One might be called the integrating or continuous sampler, and the other the instantaneous or grab sampler. Turbulent fluctuations cause the sediment-content at any point in a stream to be continually-varying; therefore, only an integrated sample, taken over a period of time long enough to get an average concentration, can truly represent the sediment-content. This integration may be made with a continuous sampler of the suction-nozzle type, which maintains the same velocity at the entrance as the undisturbed velocity of the stream at that point. (Continuous suction-nozzle samplers are now being used in the Cooperative Laboratory of the Soil Conservation Service at the California Institute of Technology.) The mean concentration may also be obtained by combining a number of small grab-samples which show the true instantaneous sediment-content

Reaction of the Wall of an Entrance Cavity Against the Afterbody of a Projectile

The cavity phase of the water entry of a projectile is described and the results are presented for the beginning of an experimental investigation of the hydrodynamic forces that affect projectile motion within a cavity. Lift-force measurements were made on two afterbody shapes that were supported so that they dug into the surface of a flowing stream of water. The similarity between these tests of models in the Free-Surface Water Tunnel and operating conditions of a full-scale projectile is discussed

Designs for suspended-load samplers based upon an experimental investigation of the disturbances caused by the instruments and analysis of sediment-laden flow

Measurements of soil losses and the determination of the rate of silt transportation by streams have disclosed the need for more efficient apparatus for sampling the suspended load. This equipment is needed especially by the Soil Conservation Service for use when the fundamentals of sediment transportation are being studied or when reliable results are required. Since most of the equipment previously used produces disturbances that affect concentration measurements, more accurate samplers are necessary. Consequently, in this investigation of sampling equipment, experiments which give an indication of the absolute accuracy, rather than a comparison between instruments of unknown accuracy, are made the basis for the practical designs

Spatially Adaptive Stochastic Methods for Fluid-Structure Interactions Subject to Thermal Fluctuations in Domains with Complex Geometries

We develop stochastic mixed finite element methods for spatially adaptive simulations of fluid-structure interactions when subject to thermal fluctuations. To account for thermal fluctuations, we introduce a discrete fluctuation-dissipation balance condition to develop compatible stochastic driving fields for our discretization. We perform analysis that shows our condition is sufficient to ensure results consistent with statistical mechanics. We show the Gibbs-Boltzmann distribution is invariant under the stochastic dynamics of the semi-discretization. To generate efficiently the required stochastic driving fields, we develop a Gibbs sampler based on iterative methods and multigrid to generate fields with $O(N)$ computational complexity. Our stochastic methods provide an alternative to uniform discretizations on periodic domains that rely on Fast Fourier Transforms. To demonstrate in practice our stochastic computational methods, we investigate within channel geometries having internal obstacles and no-slip walls how the mobility/diffusivity of particles depends on location. Our methods extend the applicability of fluctuating hydrodynamic approaches by allowing for spatially adaptive resolution of the mechanics and for domains that have complex geometries relevant in many applications

The Interactive Role of Emotional Intelligence, Attachment Style, and Resilience in the Prediction of Time Perception in Doctoral Students

The perception of time (the use of temporal categories to conceptualize experiences) affects human behavior. Students’ time perspective predicts academic outcomes: those with future orientations tend to have better academic outcomes than those with past or present, according to Zimbardo and Boyd’s psychology of time model, and may contribute to the 80% attrition rate of emergent online distance learning programs. However, their model is limited because of the exclusion of certain variables that may influence the development and maintenance of time perspective. Zimbardo and Boyd’s model claims that time perspective continually develops and changes but does not explain which variables or aspects of structure and discipline affect time perspective or its plasticity. This nonexperimental quantitative survey study was designed to ascertain whether emotional intelligence, attachment style, and resilience predicted time perspective, since each of these variables has been shown to influence behavior and relate to time perspective. Participants were 93 distance learning doctoral candidates from universities with an online format. Data gathered online from the Zimbardo Time Perception Inventory, Resilience Scale, Psychosocial Maturity Inventory, Revised Adult Attachment Scale, and a demographic questionnaire were analyzed using step-wise logistic regression analyses. Future time perspective was predicted by resilience, independent attachment style, dissertation phase, marital status (married), and gender (male). Present-hedonistic time perspective was predicted by low emotional intelligence, and dissertation phase. Present-fatalistic time perspective was predicted by low emotional intelligence. Past-positive time perspective was predicted by low anxiety attachment scores. Past-negative time perspective was predicted by an anxiety attachment style and high emotional intelligence. Results advanced Zimbaro and Boyd’s theory of time perspective by identifying these variables as predictors of time perspective and how they worked together to influence time perspective. The presence of predictors indicated that previous research was incomplete in its explanation of the relationship between time perspectives and human behaviors, such as academic achievement, because of the contribution of emotional intelligence, resilience, and attachment style to time perspective. Results also indicated the need to include these variables in prediction models of attrition rates of online doctoral programs

Past Negative Time Perspective as a Predictor of Grade Point Average in Occupational Therapy Doctoral Students

Time perspective is a fundamental dimension in psychological time, dividing human experiences into past, present, and future. Time perspective influences individuals’ functioning in all occupations, including education. Previous research has examined the relationship between time perspective and academic outcomes, but the same research has not been done, to date, with occupational therapy doctoral students. This quantitative, cross-sectional study investigated the relationship between time perspective and academic success in occupational therapy doctoral students across the United States. Data from the Zimbardo Time Perspective Inventory (ZTPI) and grade point averages (GPAs) were collected from 50 participants via surveymonkey.com. Past Negative time perspective statistically predicted GPA in the negative direction (p = .001) for students in pre-professional OTD programs, but did not predict GPA for post-professional students. Age, gender, and learning environment did not significantly influence the prediction of GPA in either group. The method and results of this study demonstrate that the ZTPI, an instrument used in the field of psychology, may have value in the profession of occupational therapy and occupational therapy doctoral programs

The assessment of pain in older people

Pain is under-recognised and under-treated in older people. It is a subjective, personal experience, only known to the person who suffers. The assessment of pain is particularly challenging in the presence of severe cognitive impairment, communication difficulties or language and cultural barriers. These guidelines set out the key components of assessing pain in older people, together with a variety of practical scales that may be used with different groups, including those with varying levels of cognitive or communication impairment. The purpose is to provide professionals with a set of practical skills to assess pain as the first step towards its effective management. The guidance has implications for all healthcare and social care staff and can be applied in all settings, including the older person’s own home, in care homes, and in hospital

OLS data system/global survey of lightning

A global lightning climatology is being assembled from the nighttime imagery of the DMSP Optical Linescan Sensor (OLS). Lightning saturates the visible channel of the OLS at nighttime and can be identified as a horizontal streak on the order of 50-100 km in horizontal extent. Lightning streaks apparent in the film strips located at the National Snow and Ice Data Center (NSIDC) prior to 1991 are being digitized. An initial survey was completed for the F7 satellite observation period January 1986 - October 1987 and for the Q satellite for the period June-July 1973. Comparisons between the OLS lightning climatology with the Arkin GPI data set during the 1986-87 El Nino event shows similar regional variations in convective activity. The digital archive of global DMSP data began at the end of February. Software is being developed at both MSFC and NSIDC to extract, navigate, and view the OLS fine and smooth imagery