Solar Cell Light Trapping beyond the Ray Optic Limit

In 1982, Yablonovitch proposed a thermodynamic limit on light trapping within homogeneous semiconductor slabs, which implied a minimum thickness needed to fully absorb the solar spectrum. However, this limit is valid for geometrical optics but not for a new generation of subwavelength solar absorbers such as ultrathin or inhomogeneously structured cells, wire-based cells, photonic crystal-based cells, and plasmonic cells. Here we show that the key to exceeding the conventional ray optic or so-called ergodic light trapping limit is in designing an elevated local density of optical states (LDOS) for the absorber. Moreover, for any semiconductor we show that it is always possible to exceed the ray optic light trapping limit and use these principles to design a number of new solar absorbers with the key feature of having an elevated LDOS within the absorbing region of the device, opening new avenues for solar cell design and cost reduction

Light trapping beyond the 4n^2 limit in thin waveguides

We describe a method for determining the maximum absorption enhancement in thin film waveguides based on optical dispersion relations. For thin film structures that support one, well-confined guided mode, we find that the absorption enhancement can surpass the traditional limit of 4n^2 when the propagation constant is large and/or the modal group velocity is small compared to the bulk value. We use this relationship as a guide to predicting structures that can exceed the 4n^2 light trapping limit, such as plasmonic and slot waveguides. Finally, we calculate the overall absorption for both single and multimode waveguides, and show examples of absorption enhancements in excess of 4n^2 for both cases

Eating Dirt

Please
This earth is blessed
Do not play in it
Sign on the wall of El Santuario de Chimayo, New Mexic

Widening the lens : a snapshot of parenting coordination

Parenting coordination is an innovative alternative dispute resolution process that assists separating or divorced parents who are deadlocked in high levels of conflict. The primary aim of this process is to reduce conflict between parents in order to support healthier child adjustment. Parenting coordinators (PCs) assist parents in disengaging from their couple relationship and replacing it with a co-parenting relationship that enables them to continue to effectively parent their children in a cooperative, if not a coordinated, fashion. This cross-sectional descriptive study investigates PCs\u27 perceptions about the process and the families engaged in it with them, based on a sample of PCs (n= 18) and families (n= 98) with whom they worked. PCs completed a survey about their closed or recently inactive parenting coordination cases. The present inquiry contributes to gaps in our knowledge about this emerging area of practice for social workers and other mental health clinicians, as well as attorneys. Results indicated that parents in this sample were highly educated, middle-aged, White and only a small number had diagnosed mental health issues. Contrary to existing literature, parents in this sample were not perceived as having significant psychopathology. The rate of personality disorders and substance abuse in this population were low. The majority of PCs did not interview children as part of the process; however results indicate that interviewing children is possibly related to parents\u27 goals being met. The differences between this sample and results noted in the few other similar studies, as well as the implications for training social workers on diagnosing personality disorders and developing the skills necessary to effectively interview children are discussed

FROM LANGUAGE TO LITERACY: STRUCTURAL FEATURES OF ACQUIRED LANGUAGES FACILITATING ENGLISH MORPHOLOGICAL AWARENESS

Morphological awareness is a crucial metalinguistic skill, specifically for English Language Learners (ELLs). Since languages differ widely in degree of orthographic opacity, degree of morphological fusion, and degree of morphological synthesis, this thesis sought to evaluate the impact of the structural features of other languages upon ELLs’ levels of English morphological awareness. Additionally, the study investigated the relationship between morphological awareness and perceived levels of literacy and oracy proficiency. Multilingual individuals responded to an online survey containing a morphological awareness task and a language history questionnaire. Each language represented in the sample was coded according to its structural features. Subsequently, the relationship between the features and morphological awareness was analyzed. Morphological awareness was impacted by a confluence of all three structural features. Knowledge of languages with higher degrees of morphological synthesis or higher degrees of orthographic opacity was found to predict higher levels of morphological awareness. Additionally, perceived English literacy proficiency explained a larger degree of the variance in English morphological awareness than perceived English oracy proficiency, though both were statistically significant. The findings indicate the acquisition of English may be impacted by familiarity with other languages and by perceptions of English proficienc

Cells in Space

Discussions and presentations addressed three aspects of cell research in space: the suitability of the cell as a subject in microgravity experiments, the requirements for generic flight hardware to support cell research, and the potential for collaboration between academia, industry, and government to develop these studies in space. Synopses are given for the presentations and follow-on discussions at the conference and papers are presented from which the presentations were based. An Executive Summary outlines the recommendations and conclusions generated at the conference