On Measuring Closed‐Loop Non‐Linearity: A Topological Approach

The focal point of this paper is to develop a measure of closed‐loop non‐linearity. In this work, the Vinnicombe metric and the Quasi‐Linear Parameter Varying representation of a non‐linear system are exploited for this purpose. It is expected that the proposed measure can serve as a decision making tool for control engineers when considering whether a linear or a non‐linear control strategy should be employed to close the loop for a non‐linear system operating in a prescribed range.     

Association between live body weight and milk urea concentration in Holstein cows

Use of milk urea (MU) concentration as a parameter for detection of nutritional imbalances requires identification and quantification of nutritional and nonnutritional factors that influence it. The objective of this study was to assess the relationship between live body weight (BW) and MU concentration in Holstein cows. Results for the test-day measurements at 7 dairy farms were obtained from the Israeli Dairy Herd Improvement Center and concomitant cow weights were registered in local computerized weighing systems. A total of 1996 cows and 25,485 records were studied. The overall unadjusted per-cow mean MU nitrogen concentration and BW were 15.3 mg/dL (SD = 3.8) and 593 kg (SD = 84), respectively. The linear association between BW and MU was negative and highly significant and the quadratic component of BW had a highly significant positive association with MU. There was a significant interaction between the association of MU and BW with lactation number. Sampling month, milk yield, milk fat percentage, and somatic cell count accounted for significant variation in MU. Predicted MU concentrations at different BW values were calculated for each parity group, by setting equations that included the estimates of the variables associated with MU and constant values (lactation averages) for the independent variables, with the exception of BW. Plotting of results showed exponential characteristics for the relationship between BW and predicted MU concentrations. At any of the considered BW, predicted MU concentrations were lower for first-parity cows. The trends and interactions found in the present study may contribute to improving accuracy of models designed to calculate urinary nitrogen excretion rates and normative milk urea concentrations.     

Empathy, self-esteem, and birth order.

An experiment to measure empathy following induced identification. Empathy is defined as sharing the presumed feelings of someone with whom you have similarity. ? of 132 lower division college students were arbitrarily assigned an attribute of nonfunctional similarity (having worked on similar tasks) with a paid model. The other ? were treated differently only in this respect. ? the Ss under each of these conditions were exposed to the model's public success, the other ? to the model's public failure. Simultaneously, a 2nd measure of palmar sweat was taken. Retrospective reports of anxiety were then obtained. Anticipated differential palmar sweating among the 4 conditions was not observed. Self-reports indicated empathy when the model was similar, p     

Probabilistic interpretation of non-destructive assay of nuclear materials

The response of a non-destructive assay system for radioactive-waste containers depends on the spatial distribution of the assayed nuclear materials in the measured container. Therefore, interpretation of measured activity in terms of contained mass will be ambiguous unless the spatial distribution is specified. A probabilistic approach is presented by which the measured activity can be interpreted in terms of a probability distribution of the contained mass. A computationally feasible procedure is formulated for calculating the conditional probability of having a certain mass given a measured value of the activity. The procedure assumes random loading of the assayed material within the container, and accounts for variation of the mass, number and position of assayed items. The procedure is generalized to account for measurement of more than one radiation. A simple explanatory example is discussed.     

Men,microclimate and society: Physiological requirements of the human body for comfortable indoor climate

The basic principles of the human thermoregulatory mechanism will be presented as background for understanding requirements of climatic comfort in hot and cold, humid and dry environmental conditions.Examples will be presented of various basic approaches, past and present, to climatically acceptable solutions for indoor comfort in severe and even extreme climatic conditions.The influence of indoor climate on the development of human societies will be discussed.     

Particle injection and mixing experiments in a one-quarter scale model bubbling fluidized bed

One significant factor in the operation of a fluidized bed combustor is the manner in which coal particles disperse and mix with the bed material upon entering the bed. A thermal tracing technique was used to study the mixing characteristics in a 1/4 scale model of a pressurized bubbling fluidized bed combustor. Particles cooled by liquid nitrogen are injected into the bed in the same way that pulverized coal will be injected. An array of thermistors is mounted inside the bed. They are used to trace the path of the cooled particles as they enter the bed and mix with the other bed material. The approximate concentrations can also be determined since heat transfer from the cooled particles to the fluidizing gas is negligible during the course of the experiment. Time-resolved images of the particle concentration show that the lateral motion of the injected particles is much greater than the lateral motion of an injected gas jet. The extended lateral motion is due to the substantial momentum of the injected particles.