Atmospheric ozone detection using a tin oxide solid state sensor

Solid-state gas sensors consist of a solid material, usually a metal oxide semiconductor, whose conductivity changes when gases adsorb onto its surface. The goal of this project is to create an ozone detection system using these sensors for use in autonomous environmental monitoring stations (such as weather balloons). To meet EPA specifications (less than 5% error), the sensor will have to have 1ppb resolution and be able to detect ozone in the range of 0-100ppb. A sensor was purchased from MicroChemical Sensors (MiCS) for adaptation to this application but the stated range of application (10-1000ppb) was 10 times the desired resolution. The bulk of the effort on this thesis focused on calibrating the sensor at its lower detection limit. The sensor was tested for its response to ozone, as well as for crosstalk with H2O, CO, NOx, SO2, and CO2. The sensor generated a measurable response to ozone levels in the proposed measurement range, but had an equally strong response to humidity (it was insensitive to the other gases). The sensor response vs. humidity and ozone concentration were measured over a range of 0ppb to 150ppb ozone and 2.5% to 85% relative humidity. The results were fitted to a modified multiple-gas Langmuir adsorption equation using an error minimization algorithm available in MATLAB. The data fit the modified Langmuir equation with an R2 value of 0.9958. The combined humidity and ozone equation was rearranged to obtain an equation for in-situ calculation of the ozone concentration. This was input into a LabVIEW program and tested against an ozone analyzer. The calibration held to within +/-2.8ppb, or +/-5% (with the exception of one extraneous data point), meeting EPA specifications

Water is valuable: the allocation of water and other resources in the New Zealand electricity market

This monograph investigates the role of the electricity market in the allocation of water and other resources used as inputs into electricity generation. We base our observations on the outputs of an original electricity spot market model designed to mimic the New Zealand electricity market. The model explains the role of water storage and the associated value of water in decision-making by generation companies. It also explains how water is allocated between on and off-peak periods and across seasons

INVESTIGATING OBSTETRIC AND GYNECOLOGIST PERCEPTIONS AND SCREENING PRACTICES FOR POSTPARTUM DEPRESSION

Literature shows that Postpartum Depression (PPD) is a very common complication of childbirth (Evans, Phillippi, & Gee, 2015). Although it is extremely common, it remains largely undetected by healthcare providers (Evans, Phillippi, & Gee, 2015). A recent study conducted by Behimehr, Curtis, Curtis, and Hart (2014) found that the public perceives OB/GYNs to carry the most responsibility in screening for Postpartum Depression. The current study was inspired by Behimehr, Curtis, Curtis, and Hart (2014) findings, and participants were assessed to obtain information about their perceptions pertaining to OB/GYNs being most responsible to screen for PPD, and whether knowledge given that the public views them as most responsible would change their perceptions of their responsibility. Screening methods employed by participants were also assessed. The current study found that OB/GYNs do not view themselves as most responsible to screen for PPD. Results also showed that OB/GYNs do view PPD screening as important and a high priority. These results have implications for not only the patients diagnosed and struggling with PPD, but also the social relationships within the family unit where a mother is suffering from PPD

Reinventing Central Office

This report presents a provocative description of a school system where resources, authority, and accountability reside primarily at the school level

Introduction

Over the past two decades, monolingual and bilingual lexicography, as well as lexical semantics, have been transformed by the use of electronic corpora, and particularly by the study of co-occurrence phenomena. Large electronic corpora have opened up many new avenues of research, and this fourth issue of Lexis brings together papers representing a range of approaches to corpus-based lexical studies. The first three articles are concerned with the exploitation of corpora for pattern extractio..