Multi-objective Optimization Models for Distributing Biosolids to Reuse Fields: A Case Study for the Blue Plains Wastewater Treatment Plant

This paper presents multi-objective optimization models that simultaneously minimize biosolids odors as well as wastewater treatment and biosolids distribution costs and can be proactively used by biosolids managers at advanced wastewater treatment plants. The computational aspects of these models are daunting, typically involving over 200,000 constraints and about 145,000 variables and are thus difficult to solve. Also, some of the mathematical terms involve bilinear, nonconvex pieces which need to be approximated. This paper presents both a numerical approximation scheme to linearize these nonconvex terms using Schur’s decomposition and SOS2 variables as well as a Dantzig–Wolfe decomposition method to improve the computational times. The computational results as well as a sensitivity analysis are performed using data from the Blue Plains advanced wastewater treatment plant in Washington, DC.     

Mapping the affective domain in young adolescents.

Administered the Coopersmith Self-Esteem Inventory, the Bialer Locus of Control Scale, Herman's Prestatie Motivatie Test, and the Defining Issues Test to 885 ll-16 yrs olds in an effort to "map" the affective domain. Interest centered on sex differences, developmental trends, relationships between the instruments, and the relationship between the affective and cognitive domains, the latter being assessed by scores on the language portion of the Stanford Achievement Test. As predicted, sex and age effects varied considerably from trait to trait. Females evidenced greater stability in affective behavior than males. Two explanations for this finding are discussed: one credits females with greater emotional maturity than males, the other regards early adolescence as a less stressful time for females than males. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic retrieval in young children as a function of type of meaning.

Studied semantic retrieval in 15 kindergartners and 15 3rd graders. Ss were timed while they verified sentences that paired animal names and properties. Properties varied in saliency (i.e., rated association strength) and in type of meaning (i.e., functional or nonfunctional properties). An attempt was made to test a theory of concept acquisition in children that maintains that functional meaning lies at the core of a concept and that identification of the functional core then leads to the derivation of a set of static identifiers (attributes). Some support was found for this hypothesis in that kindergartners were as adept as 3rd graders in retrieving functional meaning that was highly salient and dynamic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex role perceptions during adolescence.

Sex-role perceptions were examined by having 165 males and 141 females in Grades 7–12 respond to the Self-Esteem Inventory and the Nowicki-Strickland Adult Locus of Control Scale under 2 sets of instructions: (a) a standard set and (b) a set in which Ss were asked to respond as they thought a member of the same age and grade but of the opposite sex would respond. No sex differences were obtained on the 2 instruments under the standard set of instructions. Under opposite-sex instructions, however, both sexes credited males with being higher in self-esteem than females. On the locus of control scale, members of both sexes perceived themselves to be more internally controlled than members of the opposite sex. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constructive memory in conserving and nonconserving first graders.

Examined the relation between Piagetian mental operations and constructive memory. Recognition for 4 types of sentences following story presentations was assessed in 40 conserving and nonconserving 1st graders. The recognition task consisted of true and false premise and inference sentences. As hypothesized, conservers performed slightly better than nonconservers on sentences other than true inference sentences. Although novel, a true inference sentence was consistent with the overall meaning of a story. The false recognition of this type of sentence is thought to indicate active construction of meaning by the child. The results indicate that concrete mental operations relate to the process of constructive memory. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal study of attitude development in pre-, early, and later adolescent samples.

Examined changes in attitude over a 1-yr period in 382 pre-, early, and later adolescent Ss. Attitudes toward self (i.e., self-esteem—Coopersmith Self-Esteem Inventory), toward events and one's ability to control them (i.e., locus of control—Nowicki-Strickland Locus of Control Scale), and toward achievement (i.e., achievement motivation—Prestatie Motivatie Test) were examined. Results do not support the hypothesis that early adolescence is a time of dramatic change in important attitudes and perceptions. Instead, the amount of attitudinal change evidenced by Ss at each age level varied with the kind of attitude being assessed. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender difference as a factor in teachers' perceptions of students.

Elementary school teachers' perceptions of students were assessed by having teachers rate 157 boys and 127 girls in their 1st–6th grade classes on the School Behavior Check List. Multiple regression was used to examine the relationship between the student characteristics of sex, IQ, reading achievement, and grade level and teacher ratings of students on the Check List. This technique was used because sex, academic ability, and achievement are confounded variables in elementary school populations. Results show that student ability and achievement were more potent factors in teacher perceptions than gender per se. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal Retailer Load Estimates Using Stochastic Dynamic Programming

In this paper, we describe a stochastic dynamic programming methodology for determining optimal forward load estimates for electric power retailers to their suppliers. This work describes both a model as well as results based on real data for the Electric Reliability Council of Texas market and provides insights useful for planning purposes for electric power retailers in the face of uncertain market prices and end-user loads.