Student difficulties with the corrections to the energy spectrum of the hydrogen atom for the intermediate field Zeeman effect

We discuss an investigation of student difficulties with the corrections to the energy spectrum of the hydrogen atom for the intermediate field Zeeman effect using the degenerate perturbation theory. The investigation was carried out in advanced quantum mechanics courses by administering free-response and multiple-choice questions and conducting individual interviews with students. We find that students share many common difficulties related to relevant physics concepts. In particular, students often struggled with mathematical sense-making in this context of quantum mechanics which requires interpretation of the implications of degeneracy in the unperturbed energy spectrum and how the Zeeman perturbation will impact the splitting of the energy levels. We discuss how the common difficulties often arise from the fact that applying linear algebra concepts correctly in this context with degeneracy in the energy spectrum is challenging for students.Comment: Physics Education Research Conference Proceeding

Developing and Evaluating Research-Based Learning Tools for Quantum Mechanics

Here I present my work on developing and evaluating research-based learning tools for quantum mechanics. In particular, I will discuss the development and evaluation of two Quantum Interactive Learning Tutorials (QuILTs) focusing on Degenerate Perturbation Theory (DPT) and a System of Identical Particles. The QuILTs are guided by several learning theories from cognitive science and strive to help students develop a more robust understanding of the concepts covered. The investigation was carried out in advanced quantum mechanics courses by administering free-response and multiple-choice questions and conducting individual interviews with students. It was found that students share many common difficulties related to relevant physics concepts. They had difficulty with mathematical sense-making and applying linear algebra and combinatorics concepts correctly in this novel context of quantum mechanics. I describe how the research on student difficulties was used as a guide to develop and evaluate the QuILTs, which strives to help students develop a functional understanding of concepts necessary for DPT and a system of identical particles. I also discuss the development and validation of the DPT QuILT focusing on these issues and its in-class evaluation in the undergraduate and graduate courses that focused on these issues

Direct-Expansion Air-Conditioning System Performance in Low Humidity Applications: A Case Study

This paper discusses the performance of an HVAC system to maintain temperature and humidity within a candy storage warehouse. The HVAC system consists of a typical direct-expansion cooling and dehumidification coil and electric resistance reheaters. Historic energy-use data and field-measured performance data are analyzed. The importance of certain design and operating parameters such as indoor airflow quantity, cooling coil apparatus dew-point temperature and the air-handling unit's fan operating strategy on the dehumidification performance of the HVAC system are discussed and analyzed. It also offers recommendations for design and operation of such systems

Personality in Chimpanzees (Pan troglodytes): Exploring the Hierarchical Structure and Associations with the Vasopressin V1A Receptor Gene

One of the major contributions of recent personality psychology is the finding that traits are related to each other in an organized hierarchy. To date, however, researchers have yet to investigate this hierarchy in nonhuman primates. Such investigations are critical in confirming the cross-species nature of trait personality helping to illuminate personality as neurobiologically-based and evolutionarily-derived dimensions of primate disposition. Investigations of potential genetic polymorphisms associated with hierarchical models of personality among nonhuman primates represent a critical first step. The current study examined the hierarchical structure of chimpanzee personality as well as sex-specific associations with a polymorphism in the promoter region of the vasopressin V1a receptor gene (AVPR1A), a gene associated with dispositional traits, among 174 chimpanzees. Results confirmed a hierarchical structure of personality across species and, despite differences in early rearing experiences, suggest a sexually dimorphic role of AVPR1A polymorphisms on hierarchical personality profiles at a higher-order level