TOPICS IN POLYMER PHYSICS（With CD-Rom）

This important book emphasizes the basic derivation of many key equations used in polymer physics. Phrases such as “it can be easily shown that” and “it readily follows that”, seen in many textbooks, are seldom used here. The models, assumptions and key equations underlying concepts are presented in the text; details used in the derivations are given in the accompanying CD-Rom. The CD-Rom also contains problems （with solutions in many cases） which test the reader＇s grasp of the material, as well as a glossary of symbols.

First order dynamics approaching of broiler chicken deep body temperature response to step changes in ambient temperature

Traditional environmental control methods for poultry housing which rely solely on environmental factors fall short in meeting thermal and physiological needs of the animals.New methods are needed that factor in the physiological needs and responses of the animals in order to maximize well-being of the animals and minimize heat stress.Deep body temperature(DBT)has been shown in the literature to be a strong indicator of heat stress,therefore studies are needed that help us gain a deeper understanding of the relationship between this variable and environmental conditions.The aim of this study was to identify the order of the dynamic response of poultry DBT to large step changes in ambient temperature(AT).Temperature steps had to be big enough to take the chickens out of their homeothermic zone.A total of 46 DBT/AT data sets with 23 upward AT steps and 23 downward AT steps were obtained using a biotelemetry system,and involving three chickens.DBT responses of individual chickens to step changes in AT were found to have a 0.88 average Pearson correlation suggesting consistency in chickens’responses to the same stimuli(p<0.0005).The data indicated that DBT responses to AT followed a first order behavior in most cases with an average time constant of 1.6 h,and the curve fitting method was used to validate this observation.There was a 0.88 average correlation between DBT model and measured data(p<0.0005).These results indicate statistical significance in the data used and the model derived from it.In conclusion,it is reasonable to assume that the dynamic response of poultry DBT to large step changes in ambient temperature follows a first order model.Although further studies are needed to more fully derive the model,this study provided a stepping-stone towards gaining a better understanding of the relationship between DBT and AT,therefore taking us one step closer towards making optimal management and risk assessment decisions that are based on physiological needs of the chickens.

SPC and Kalman filter-based fault detection and diagnosis for an air-cooled chiller

Buildings worldwide account for nearly 40%of global energy consumption.The biggest energy consumer in buildings is the heating,ventilation and air conditioning(HVAC)systems.In HVAC systems,chillers account for a major portion of the energy consumption.Maintaining chillers in good conditions through early fault detection and diagnosis is thus a critical issue.In this paper,the fault detection and diagnosis for an air-cooled chiller with air coming from outside in variable flow rates is studied.The problem is difficult since the air-cooled chiller is operating under major uncertainties including the cooling load,and the air temperature and flow rate.A potential method to overcome the difficulty caused by the uncertainties is to perform fault detection and diagnosis based on a gray-box model with parameters regarded as constants.The method is developed and verified by us in another paper for a water-cooled chiller with the uncertainty of cooling load.The verification used a Kalman filter to predict parameters of a gray-box model and statistical process control(SPC)for measuring and analyzing their variations for fault detection and diagnosis.The gray-box model in the method,however,requires that the air temperature and flow rate be nearly constant.By introducing two new parameters and deleting data points with low air flow rate,the requirement can be satisfied and the method can then be applicable for an air-cooled chiller.The simulation results show that the method with the revised model and some data points dropped improved the fault detection and diagnosis(FDD)performance greatly.It can detect both sudden and gradual air-cooled chiller capacity degradation and sensor faults as well as their recoveries.

Evaluation of the wind energy potential of two south west sites in Nigeria

Wind resource assessment is a crucial first step in gauging the potential of a site to produce energy from wind turbines. In this paper, the wind energy potential of Abeokuta （07°03＇N, 03°19＇E） and Ijebu-Ode （06°47＇N, 03°58＇E）, two south west sites in Nigeria were examined. Twenty years （1990-2010） of monthly mean wind data from a 10m height were subjected to two-parameter Weibull analysis and other statistical analyses. The results show that the average annual mean wind speed variation for Abeokuta ranges from 2.2 to 5.0 m/s. For Ijebu-Ode, it ranges from 2.0 to 5.0m/s. The wind power density variation based on the Weibull analysis ranges from 4.26 to 24.51 W/m2 for Abeokuta and from 8.54 to 76.46 W/m2 for Ijebu-Ode. Ijebu-Ode was found to be the better of the two sites in terms of annual variation of mean wind speed.