Essays on Places and Economic Inequality

This dissertation uses changes across space to understand economic inequality. Chapter one examines people’s ties to places. If people are tied to places by family and experiences, then welfare will be less equal across space. It presents evidence that this is the case, with formulae that show how this makes local policies less wasteful in declining areas. Chapter two shows that young adults, ages 25 to 35, who live in the same neighborhoods as their parents experience stronger earnings recoveries after a job displacement than those who live farther away. It presents some evidence that these differences are driven by parental help with grandchildren and perhaps help from parents in identifying new jobs. Chapter three uses changes in housing prices and rents to study inequality in standards of living. It suggests that changes in income inequality since 1930 have caused similar changes in housing expenditures, mostly through changes in the value of particular neighborhoods.PHDEconomicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145975/1/zabek_1.pd

Wind-driven pyroelectric energy harvesting device

Pyroelectric materials have recently received attention for harvesting waste heat owing to their potential to convert temperature fluctuations into useful electrical energy. One of the main challenges in designing pyroelectric energy harvesters is to provide a means to induce a temporal heat variation in a pyroelectric material autonomously from a steady heat source. To address this issue, we propose a new form of wind-driven pyroelectric energy harvester, in which a propeller is set in rotational motion by an incoming wind stream. The speed of the propeller's shaft is reduced by a gearbox to drive a slider-crank mechanism, in which a pyroelectric material is placed on the slider. Thermal cycling is obtained as the reciprocating slider moves the pyroelectric material across alternative hot and cold zones created by a stationary heat lamp and ambient temperature, respectively. The open-circuit voltage and closed-circuit current are investigated in the time domain at various wind speeds. The device was experimentally tested under wind speeds ranging from 1.1 to 1.6 m s-1 and charged an external 100 nF capacitor through a signal conditioning circuit to demonstrate its effectiveness for energy harvesting. Unlike conventional wind turbines, the energy harvested by the pyroelectric material is decoupled from the wind flow and no mechanical power is drawn from the transmission; hence the system can operate at low wind speeds (-1).</p

A novel pyroelectric generator utilising naturally driven temperature fluctuations from oscillating heat pipes for waste heat recovery and thermal energy harvesting

Low temperature thermal to electrical energy converters have the potential to provide a route for recovering waste energy. In this paper, we propose a new configuration of a thermal harvester that uses a naturally driven thermal oscillator free of mechanical motion and operates between a hot heat source and a cold heat sink. The system exploits a heat induced liquid-vapour transition of a working fluid as a primary driver for a pyroelectric generator. The two-phase instability of a fluid in a closed looped capillary channel of an oscillating heat pipe (OHP) creates pressure differences which lead to local high frequency temperature oscillations in the range of 0.1–5 K. Such temperature changes are suitable for pyroelectric thermal to electrical energy conversion, where the pyroelectric generator is attached to the adiabatic wall of the OHP, thereby absorbing thermal energy from the passing fluid. This new pyroelectric-oscillating heat pipe (POHP) assembly of a low temperature generator continuously operates across a spatial heat source temperature of 55 °C and a heat sink temperature of 25 °C, and enables waste heat recovery and thermal energy harvesting from small temperature gradients at low temperatures. Our electrical measurements with lead zirconate titanate (PZT) show an open circuit voltage of 0.4 V (AC) and with lead magnesium niobate–lead titanate (PMN-PT) an open circuit voltage of 0.8 V (AC) at a frequency of 0.45 Hz, with an energy density of 95 pJ cm−3 for PMN-PT. Our novel POHP device therefore has the capability to convert small quantities of thermal energy into more desirable electricity in the nW to mW range and provides an alternative to currently used batteries or centralised energy generation

Tau Polarimetry with Multi Meson States

It is demonstrated that the analyzing power of multi-meson final states in semileptonic $\tau$ decays with respect to the $\tau$ spin is equal and maximal for all decay modes.Comment: 4 pages, LaTex. The complete paper is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ , or via www at http://ttpux2.physik.uni-karlsruhe.de/cgi-bin/preprints

Assessing the efficacy of medetomidine and tiletamine-zolazepam for remote immobilisation of feral horses (Equus caballus)

Context The study of any wild animal's home range requires the collection of spatiotemporal data, obtained independently of climatic conditions or time of day. This can be achieved by the attachment of global positioning system (GPS) data loggers, which, in large species, is best achieved by remote immobilisation. Feral horses (Equus caballus) usually occupy remote areas of Australia; however, a considerable population increase has been observed in a close proximity to metropolitan areas of the Australian east coast, creating increasing conflict with human interests. Aim The aim of the present study was to investigate the efficacy of remote chemical immobilisation of feral horses with medetomidine combined with tiletamine-zolazepam to facilitate placement of satellite GPS collars. Methods Nine feral horses were darted from the ground with 60mg (i.m.) medetomidine and 1500mg (i.m.) tiletamine-zolazepam. The effects of medetomidine were reversed with 50-100mg (i.m. or i.v.) atipamezole 30-40min after induction (IV/IM). Physiological variables monitored during anaesthesia were heart rate, respiratory rate, temperature and oxygen haemoglobin saturation (Spo2). Key results All horses were successfully immobilised with between one and three darts (n≤9). The mean (± s.e.m.) dose of medetomidine was 0.15±0.01mg kg-1, whereas that of tiletamine-zolazepam was 3.61±0.16mg kg-1. Mean time from darting to lateral recumbency was 13.3±2.7min and mean recumbency time was 54±13min. Vital signs for all anaesthetised animals remained within the normal range during anaesthesia, with the exception of one animal exhibiting a transient drop in Spo2. There were no deaths. Key conclusions The combination of medetomidine and tiletamine-zolazepam provided adequate anaesthesia in feral horses in the field for application of GPS collars. Implications Although a limited number of horses was immobilised, the present study shows that the combination of medetomidine and tiletamine-zolazepam provides effective short-term anaesthesia for feral horses, affording a practical and field-accessible capture technique. This method could also be applied to other management actions requiring the safe and humane capture of feral horses