Current activities in standardization of high-temperature, low-cycle-fatigue testing techniques in the United States

The American Society for Testing and Materials (ASTM) standard E606-80 is the most often used recommended testing practice for low-cycle-fatigue (LCF) testing in the United States. The standard was first adopted in 1977 for LCF testing at room temperature and was modified in 1980 to include high-temperature testing practices. Current activity within ASTM is aimed at extending the E606-80 recommended practices to LCF under thermomechanical conditions, LCF in high-pressure hydrogen, and LCF in metal-matrix composite materials. Interlaboratory testing programs conducted to generate a technical base for modifying E606-80 for the aforementioned LCF test types are discussed

Dr. Kenneth P. Pruess Obituary

Dr. Kenneth P. Pruess, age 84, of Lincoln, Nebraska, died 11 December 2016. Kenneth was Professor of Entomology Emeritus at the University of Nebraska-Lincoln. He was born 21 June 1932 in Troy, Indiana, to Elmer and Clara (Grass) Pruess. Kenneth graduated from Purdue University in 1954 and earned his M.S. in Entomology in 1955 and Ph.D. in 1957, both from The Ohio State University. His dissertation was titled “Studies on the Clover Root Borer, Hylastinus obscurus (Marsham).” He married Neva Currie on 15 June 1963. He worked at the University of Nebraska’s North Platte Experiment Station from 1957–1965, Entomology Department at UNL from 1965–1997, and was Entomology Department UNL Emeritus from 1997 until the time of his death, continuing his research until 8 December 2016. Throughout his career, Kenneth conducted research on a wide variety of topics. Initially, he was hired at North Platte to study the army cutworm, Euxoa auxiliaris (Grote), which was a major pest of wheat in western Nebraska. He published several studies that helped document their summer migration from the Great Plains to the Rockies. One of these he co-authored with his wife, who also had graduate training in entomology. They used binoculars to track the direction of flight at night of army cutworm moths by watching them as they flew in front of the moon. He began long-range studies of the population dynamics of rangeland grasshoppers, which continued for decades after he moved to Lincoln. He was an early adopter of using microcomputers in teaching and developed programs for computer modeling in pest management. He conducted several studies on biology and management of western corn rootworms, including a 1968–1970 study on areawide management of adult rootworms over a 16-square-mile area. His study was the first to evaluate the potential of areawide management of corn rootworms. Later, he began studies on natural history of aquatic insects, particularly focused on black flies. He used molecular techniques to study black fly taxonomy and then alfalfa weevil taxonomy. The week of his death, he was working on finalizing a manuscript on alfalfa weevil molecular taxonomy for journal submission

Dr. Kenneth P. Pruess Obituary

Dr. Kenneth P. Pruess, age 84, of Lincoln, Nebraska, died 11 December 2016. Kenneth was Professor of Entomology Emeritus at the University of Nebraska-Lincoln. He was born 21 June 1932 in Troy, Indiana, to Elmer and Clara (Grass) Pruess. Kenneth graduated from Purdue University in 1954 and earned his M.S. in Entomology in 1955 and Ph.D. in 1957, both from The Ohio State University. His dissertation was titled “Studies on the Clover Root Borer, Hylastinus obscurus (Marsham).” He married Neva Currie on 15 June 1963. He worked at the University of Nebraska’s North Platte Experiment Station from 1957–1965, Entomology Department at UNL from 1965–1997, and was Entomology Department UNL Emeritus from 1997 until the time of his death, continuing his research until 8 December 2016. Throughout his career, Kenneth conducted research on a wide variety of topics. Initially, he was hired at North Platte to study the army cutworm, Euxoa auxiliaris (Grote), which was a major pest of wheat in western Nebraska. He published several studies that helped document their summer migration from the Great Plains to the Rockies. One of these he co-authored with his wife, who also had graduate training in entomology. They used binoculars to track the direction of flight at night of army cutworm moths by watching them as they flew in front of the moon. He began long-range studies of the population dynamics of rangeland grasshoppers, which continued for decades after he moved to Lincoln. He was an early adopter of using microcomputers in teaching and developed programs for computer modeling in pest management. He conducted several studies on biology and management of western corn rootworms, including a 1968–1970 study on areawide management of adult rootworms over a 16-square-mile area. His study was the first to evaluate the potential of areawide management of corn rootworms. Later, he began studies on natural history of aquatic insects, particularly focused on black flies. He used molecular techniques to study black fly taxonomy and then alfalfa weevil taxonomy. The week of his death, he was working on finalizing a manuscript on alfalfa weevil molecular taxonomy for journal submission

The Impact of Task- and Team-Generic Teamwork Skills Training on Team Effectiveness

This study examined the effects of training team members in three task- and teamgeneric teamwork skills: planning and task coordination, collaborative problem solving, and communication. We first examined the degree to which task- and team-generic teamwork skills training impacted team performance on a task unrelated to the content of the training program.We then examined whether the effects of task- and team-generic teamwork skills training on team performance were due to the transfer of skills directly related to planning and task coordination, collaborative problem solving, and communication. Results from 65 four-person project teams indicated that task- and team-generic teamwork skills training led to significantly higher levels of team performance. Results also indicated that the effects of task- and teamgeneric teamwork skills training on team performance were mediated by planning and task coordination and collaborative problem solving behavior. Although communication was positively affected by the task- and team-generic teamwork skills training, it did not mediate the relationship between task- and team-generic teamwork skills training and team performance.Theoretical and practical implications of these results are discussed, as well as possible limitations and directions for future research

System Identification for Model Predictive Control of Building Region Temperature

Model predictive control (MPC) is a promising technology for energy cost optimization of buildings because it provides a natural framework for optimally controlling such systems by computing control actions that minimize the energy cost while meeting constraints. In our previous work, we developed a cascaded MPC framework capable of minimizing the energy cost of building zone temperature control applications. The outer loop MPC computes power set-points to minimize the energy cost while ensuring that the zone temperature is maintained within its comfort constraints. The inner loop MPC receives the power set-points from the outer loop MPC and manipulates the zone temperature set-point to ensure that the zone power consumption tracks the power set-points computed by the outer layer MPC. Since both MPCs require a predictive model, a modeling framework and system identification (SI) methodology must be developed that is capable of accurately predicting the energy usage and zone temperature for a diverse range of building zones. In this work, two grey-box models for the outer and inner loop MPCs are developed and parameterized. The model parameters are fit to input-output data for a particular zone application so that the resulting model accurately predicts the behavior of the zone. State and disturbance estimation, which is required by the MPCs, is performed via a Kalman filter with a steady-state Kalman gain. The model parameters and Kalman gains of each grey-box model are updated in a sequential fashion. The significant disturbances affecting the zone temperature (e.g., outside temperature and occupancy) may typically be considered as a slowly varying disturbance (with respect to the control time-scale). To prevent steady-state offset in the identified model caused by the slowly time-varying disturbance, a high-pass filter is applied to the input-output data to filter out the effect of the disturbance. The model parameters are subsequently computed from the filtered input-output data without the Kalman filter applied. The Kalman gain is also adjusted as the model parameters are updated to ensure stability of the resulting observer and for optimal estimation. After the model parameters are computed, the steady-state Kalman gain matrix is parameterized and the parameters are updated using the prediction error method with the unfiltered input-output data and the updated model parameters. The Kalman gain update methodology is advantageous because it avoids the need to estimate the noise statistics. Stability of the observer is verified after the parameters are updated. If the updated parameters result in an unstable observer, the update is rejected and the previous parameters are retained. Additionally, since a standard quadratic cost function that penalizes the squared prediction error is sensitive to data outliers in the prediction error method, a piecewise defined cost function is employed to reduce its sensitivity to outliers and to improve the robustness of the SI methodology. The cost function penalizes the squared prediction error when the error is within certain thresholds. When the error is outside the thresholds, the cost function evaluates to a constant. The SI algorithm is applied to a building zone to assess the approach

Dual tasking in Parkinson's disease: cognitive consequences while walking

Published in final edited form as: Neuropsychology. 2017 September; 31(6): 613–623. doi:10.1037/neu0000331.OBJECTIVE: Cognitive deficits are common in Parkinson's disease (PD) and exacerbate the functional limitations imposed by PD's hallmark motor symptoms, including impairments in walking. Though much research has addressed the effect of dual cognitive-locomotor tasks on walking, less is known about their effect on cognition. The purpose of this study was to investigate the relation between gait and executive function, with the hypothesis that dual tasking would exacerbate cognitive vulnerabilities in PD as well as being associated with gait disturbances. METHOD: Nineteen individuals with mild-moderate PD without dementia and 13 age- and education-matched normal control adults (NC) participated. Executive function (set-shifting) and walking were assessed singly and during dual tasking. RESULTS: Dual tasking had a significant effect on cognition (reduced set-shifting) and on walking (speed, stride length) for both PD and NC, and also on stride frequency for PD only. The impact of dual tasking on walking speed and stride frequency was significantly greater for PD than NC. Though the group by condition interaction was not significant, PD had fewer set-shifts than NC on dual task. Further, relative to NC, PD showed significantly greater variability in cognitive performance under dual tasking, whereas variability in motor performance remained unaffected by dual tasking. CONCLUSIONS: Dual tasking had a significantly greater effect in PD than in NC on cognition as well as on walking. The results suggest that assessment and treatment of PD should consider the cognitive as well as the gait components of PD-related deficits under dual-task conditions. (PsycINFO Database Record)

Economic Model Predictive Control for Variable Refrigerant Systems

Variable refrigerant (VRF) systems are in a unique position to be combined with economic model predictive control (MPC) in order to reap significant benefits. In buildings with a variable utility price, it is feasible to use the building mass to shift a portion of the building heating, ventilation, and air conditioning (HVAC) load from the high priced (peak) period to the low priced (off-peak) period. It is also feasible for further savings to be visualized through a reduction of the monthly demand charge. By employing the building mass as an element to store thermal energy, one can see a significant reduction in utility costs. The MPC algorithm can accomplish this by using the building mass to store and release heat at the appropriate time to reduce HVAC usage during the peak utility price periods. This is accomplished through MPC of the indoor air temperature within the acceptable temperature set point limits. With proper, linear models, a linear programming (LP) algorithm can be employed to perform the economic optimization over the future time horizon. Savings in commercial buildings estimate HVAC cost savings from --% to --% annually

Self-starting optical–electrical–optical homodyne clock recovery for phase-modulated signals

We propose a novel self-homodyne optical–electrical–optical clock recovery technique for binary phase-shift keying (BPSK) signals using commercial optical and electrical components. We present the principle of operation as well as a proof-of-concept experiment for a 10.7 Gb/s BPSK signal clock recovery transmitted over a dispersion-compensated link of 20 km of single-mode fiber. Suppression of pattern-related frequency noise at the output of the recovered clock is shown. The timing jitter of the recovered clock at 10.7 GHz was measured to be ∼450 fs (integration range: 100 Hz–10 MHz)

Problems Encountered With Control Networks in Highly-Restructurable Digital Systems

This paper discusses problems encountered with control networks in highly restructurable digital systems. In particular the treatment of implementation errors is covered with emphasis on concurrent processing. The implementation of concurrent processing networks may result in errors which will be quite complex to detect and systematic methods are warranted. Four meta control elements are employed in obtaining convenient concurrent structures. We analyze several error detecting schemes and conclude that the arc-node method with node partitioning appears to be the most realistic approach at this time