Real time optimization with multivariable control is required to maximize profits

Optimization of an operating process unit performed in real time with an on-line process control computer has a number of significant advantages over an optimization executed by an off-line computer. These advantages are derived from the process control computer's abilities to know precisely the current state of the operation, to control the process at the set of interacting constraints representing the predicted future state of the operation, and to provide direct feedback on how valid the predictions actually are. Multivariable interactive computer control techniques which recognize constraints are required to hold the process at its most profitable operating conditions.     

External corrosion in coal-fired boilers: Assessment from laboratory data

The reactions of coal impurity constituents in the flame are discussed in this paper with particular reference to the formation of corrosive deposits on the heat transfer surfaces in boilers. Consideration is given to the factors which make it difficult to give accurate predictions of metal wastage rates in these environments at high temperatures on the basis of laboratory experiments. These difficulties arise from variations in the operating conditions and are particularly problematic for the steam generating tubes which are located in the walls of the combustion chamber. Non-equilibrium reducing conditions can exist in this region and there is a large temperature gradient through the ash deposit and the corrosion scale on the tube surface. Molten sulphate deposits can be formed on the superheater tubes at the highest temperatures, and the temperature gradient again has an important influence on corrosion rates. The nature and concentrations of the coal impurities and also the influence of heat flux therefore have to be taken into account in the prediction of corrosion rates from laboratory data which may frequently have been obtained under isothermal conditions.     

Improving the reliability of eyewitness identification: Putting context into context.

We examined the effects of context reinstatement procedures on eyewitness identification accuracy. Subjects were 290 undergraduates who viewed a videotaped reenactment of a liquor store robbery and, in a later session, attempted to identify the robber from a lineup parade. Two types of context reinstatement procedures were examined together with eight encoding, storage, and retrieval variables manipulated within the stimulus videotape and the lineup procedures. Disguise of the robber impaired identification accuracy (pppp?=?.01), and exposure to mug shots (p?=?.05; although in a manner contrary to our expectation). These interactions indicated that lineup context cues improved identification accuracy in the high-similarity, 2-week retention interval, and no mug-shots conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Producer estimates of prevalence and perceived importance of lameness in dairy herds with tiestalls,freestalls, and automated milking systems

Lameness is one of the most important welfare and productivity concerns in the dairy industry. Our objectives were to obtain producers' estimates of its prevalence and their perceptions of lameness, and to investigate how producers monitor lameness in tiestall (TS), freestall with milking parlor (FS), and automated milking system (AMS) herds. Forty focal cows per farm in 237 Canadian dairy herds were scored for lameness by trained researchers. On the same day, the producers completed a questionnaire. Mean herd-level prevalence of lameness estimated by producers was 9.0% (±0.9%; ±SE), whereas the researchers observed a mean prevalence of 22.2% (±0.9%). Correlation between producer- and researcher-estimated lameness prevalence was low (r = 0.19) and mean researcher prevalence was 1.6, 1.8, and 4.1 times higher in AMS, FS, and TS farms, respectively. A total of 48% of producers thought lameness was a moderate or major problem in their herds (TS = 34%; AMS =53%; FS = 59%). One third of producers considered lameness the highest ranked health problem they were trying to control, whereas two-thirds of producers (TS = 43%; AMS = 63%; FS = 71%) stated that they had made management changes to deal with lameness in the past 2 yr. Almost all producers (98%) stated they routinely check cows to identify new cases of lameness; however, 40% of producers did not keep records of lameness (AMS = 24%; FS = 23%; TS = 60%). A majority (69%) of producers treated lame cows themselves immediately after detection, whereas 13% relied on hoof-trimmer or veterinarians to plan treatment. Producers are aware of lameness as an issue in dairy herds and almost all monitor lameness as part of their daily routine. However, producers underestimate lameness prevalence, which highlights that lameness detection continues to be difficult in in all housing systems, especially in TS herds. Training to improve detection, record keeping, identification of farm-specific risk factors, and treatment planning for lame cows is likely to help decrease lameness prevalence.     

Using nacelle‐based wind speed observations to improve power curve modeling for wind power forecasting

Wind power forecasting for projection times of 0–48 h can have a particular value in facilitating the integration of wind power into power systems. Accurate observations of the wind speed received by wind turbines are important inputs for some of the most useful methods for making such forecasts. In particular, they are used to derive power curves relating wind speeds to wind power production. By using power curve modeling, this paper compares two types of wind speed observations typically available at wind farms: the wind speed and wind direction measurements at the nacelles of the wind turbines and those at one or more on‐site meteorological masts (met masts). For the three Australian wind farms studied in this project, the results favor the nacelle‐based observations despite the inherent interference from the nacelle and the blades and despite calibration corrections to the met mast observations. This trend was found to be stronger for wind farm sites with more complex terrain. In addition, a numerical weather prediction (NWP) system was used to show that, for the wind farms studied, smaller single time‐series forecast errors can be achieved with the average wind speed from the nacelle‐based observations. This suggests that the nacelle‐average observations are more representative of the wind behavior predicted by an NWP system than the met mast observations. Also, when using an NWP system to predict wind farm power production, it suggests the use of a wind farm power curve based on nacelle‐average observations instead of met mast observations. Further, it suggests that historical and real‐time nacelle‐average observations should be calculated for large wind farms and used in wind power forecasting. Copyright © 2011 John Wiley & Sons, Ltd.     

Specific impairments in self-regulation in children exposed to alcohol prenatally

The present study utilizes a conceptual framework derived from theories of cognition to explain the pattern of behavioral and learning problems observed in subjects with fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE). Based on a modern interpretation of Luria's theory of self-regulation, this study used a neuropsychological test battery to compare 10 subjects (mean age = 13 years) having FAS/FAE with 10 control subjects (mean age = 12 years and 9 months). Subjects with FAS/FAE were relatively high functioning and did not significantly differ from controls with respect to receptive vocabulary. However, those with FAS/FAE exhibited greater difficulty than controls on tasks that involved the manipulation of information and goal management in working memory (e.g., Planning, Controlled Oral Word Association, etc). Both groups performed equally well on some tasks that demanded rule learning (Delayed Response) and response inhibition (Go-No-Go). The above impairments were interpreted to be reflective of selective rather than generalized disruptions of neural networks that subserve working memory.     

Binding of Candida albicans yeast cells to mouse popliteal lymph node tissue is mediated by macrophages

We previously reported that Candida albicans yeast cells adhere to the macrophage-rich medullary and subcapsular sinus areas of mouse lymph node tissue. To determine whether the yeast cell-lymph node interaction is mediated by macrophages, the effect of specific elimination of macrophages on yeast cell binding was studied, and yeast cell adherence was correlated with the ingestion of India ink by lymph node cells. Macrophage elimination was done by use of liposome-containing dichloromethylene diphosphonate (L-Cl2MDP). Mice were injected in the hind footpads with the L-Cl2MDP preparation, popliteal lymph nodes were removed 5 days later, and yeast cell adherence was determined by an ex vivo binding assay. As controls, lymph nodes from mice that received footpad injections of either phosphate-buffered saline (PBS) alone or liposome-containing PBS were used. Use of macrophage- and neutrophil-specific monoclonal antibodies in tissue immunostaining showed that the L-Cl2MDP treatment eliminated macrophages but not neutrophils from the medullary and subcapsular sinus areas of the popliteal lymph nodes. A striking reduction of yeast cell adherence occurred with lymph nodes from L-Cl2MDP-treated mice compared with lymph nodes from control animals. The lymph node-yeast cell binding patterns of L-Cl2MDP-treated and control mice were the same regardless of mouse strain, sex, or T-cell competency. Results of India ink experiments, in which India ink was injected into footpads of mice and was rapidly taken up by popliteal lymph node macrophages, showed a strong correlation between yeast adherence and India ink staining of cells. In addition, the interaction of yeast cells with lymph node tissue from normal mice was not significantly affected by the addition of two extracellular matrix proteins, fibronectin and laminin, during the ex vivo adherence assay. These data indicate that medullary and subcapsular sinus lymph node macrophages express an adhesion system similar to that described for mouse splenic marginal zone macrophages.