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Urban Spaces in Nineteenth-Century Ireland, edited by Georgina Laragy, Olwen Purdue, and Jonathan Jeffrey Wright; pp. ix + 212. Liverpool: Liverpool University Press, 2018, 85.00 [pounds sterling], $130.00. There have [...]

Current U.S. government policy seeks to achieve a completely carbon-free economy by 2050, with a carbon-free electricity sector by 2035 (per executive orders #14008 and #14057). To address these goals, the U.S. Department of Energy is evaluating strategies and technologies that support the production, utilization, transport, and storage of hydrogen (via initiatives such as Department of Energy's (DOE) Energy Earthshot--Hydrogen and various DOE funding opportunity announcements). A carbon-free fuel such as hydrogen cannot be overvalued in a dynamic electric energy sector seeking to decarbonize. One of the most important technologies needed to achieve the goal of a carbon-free electricity sector is a 100% hydrogen-fueled gas turbine. Accommodating hydrogen-based fuels has been a key goal for various original engine manufacturers (OEMs) for many years, but much more research and development (R&D) is needed. The purpose of this paper is to highlight the current state-of-the-art of hydrogen turbine technology, especially regarding nitrogen oxide (NOX) emissions compared to natural gas-fueled turbines. NOX is the primary criteria pollutant from thermally driven combustion turbines and should be controlled to levels that are equivalent to or below existing standards (as reported "existing standards" for hydrogen-fueled gas turbines may need to be rebaselined). This paper will provide an overview of hydrogen as a fuel and various NOX emissions control techniques that are relevant for hydrogen-based fuels. A conclusion from this overview is that, with some level of R&D, NOX emissions from hydrogen-fueled gas turbines can be controlled to levels similar to those produced by state-of-the-art (SOTA) natural gas-fueled combustion turbines while remaining competitive in terms of performance and efficiency. [ABSTRACT FROM AUTHOR]

In gas turbines, the hot gas exiting the combustor can have temperatures as high as 2000 °C, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the entering hot gas could damage the disks, its ingestion must be minimized. This is carried out by rim seals and by introducing a cooler flow from the compressor (sealing flow) into the wheelspace. Ingress and egress into rim seals are driven by the stator vanes, the rotor and its rotation, and the rotor blades. This study focuses on the ingress and egress driven by the rotor and its rotation. This is carried out by performing wall-resolved large eddy simulation (LES) around an axial seal in a rotor–stator configuration without vanes and blades. Results obtained show the mechanisms by which the rotor and its rotation induce ingress, egress, and flow trajectories. Kelvin–Helmholtz instability was found to create a wavy shear layer and displacement thickness that produces alternating regions of high and low pressures around the rotor side of the seal. Vortex shedding on the backward-facing side of the seal and its impingement on the rotor side of the seal also produces alternating regions of high and low pressures. The locations of the alternating regions of high and low pressures were found to be statistically stationary and to cause ingress to start on the rotor side of the seal. Vortex shedding and recirculating flow in the seal clearance also cause ingress by entrainment. With the effects of the rotor and its rotation on ingress and egress isolated, this study enables the effects of stator vanes and rotor blades to be assessed. [ABSTRACT FROM AUTHOR]

Apartment houses were controversial insertions into the built environment of Canadian cities in the early twentieth century. More recently, some early apartments have been demolished and replaced by high-rise or non-residential buildings, but others have acquired heritage status. Small-scale, originally walk-up apartments on inner suburban residential streets are praised for their domestic and homely characteristics, precisely what they were thought to lack when first erected. Through a series of brief case studies, this article traces the changing fortunes of pre-First World War apartment houses in Toronto and Montreal. It charts both their 'real' experience of neglect, abandonment, reuse, conservation or renovation, and their representation in literature and on screen: as 'bohemian', 'modern', home to dysfunctional or marginal characters, or complex mixtures of semi-public and semi-private space. While survival or demolition has sometimes been a matter of chance, it is also evident that geography is critical in determining their fate. Keywords: Toronto, Montreal, apartments, housing, urban planning, literary representation, film Les immeubles de rapport ont ete une insertion controversee dans les zones construites des villes canadiennes du debut du vingtieme siecle. Plus recemment, certains de ces premiers appartements ont ete demolis et remplaces par des gratte-ciels ou par des immeubles non residentiels, mais d'autres ont acquis le statut de batiments proteges. Les immeubles de petite taille accessibles par des escaliers dans les rues des banlieues residentielles sont loues pour leurs caracteristiques d'interieurs chaleureux et accueillants, ce qui etait precisement ce qu'on leur reprochait de manquer a l'epoque oU ils ont ete construits. A travers une serie d'etudes de cas breves, cette etude retrace les revers de fortune des immeubles de rapport eriges avant la premiere guerre mondiale a Toronto et a Montreal. Elle rend compte a la fois de leur 'veritable' manque d'entretien, de leur abandon, reutilisation, preservation et renovation et de leur representation dans la litterature et au cinema comme logement 'boheme', 'moderne' pour les personnages marginaux ou dysfonctionnels mais aussi de melanges complexes d'espaces semi-publics et semi-prives. Tandis que la survie ou la demolition de ces batiments a parfois ete une question de chance, il est manifeste que la geographie joue un role crucial dans la determination de leur sort. Mots cles: Toronto, Montreal, appartements, logement, urbanisme, representation litteraire, film, The apartment house has had a chequered and controversial career in Canadian cities. In the early twentieth century it was regarded with suspicion if not downright opposition, especially in Toronto, [...]

Large-eddy simulations (LES) were performed to study the turbulent flow in a channel of height H with a staggered array of pin fins with diameter D = H/2 as a function of heating loads that are relevant to the cooling of turbine blades and vanes. The following three heating loads were investigated—wall-to-coolant temperatures of Tw/Tc = 1.01, 2.0, and 4.0—where the Reynolds number at the channel inlet was 10,000 and the back pressure at the channel outlet was 1 bar. For the LES, two different subgrid-scale models—the dynamic kinetic energy model (DKEM) and the wall-adapting local eddy-viscosity model (WALE)—were examined and compared. This study was validated by comparing with data from direct numerical simulation and experimental measurements. The results obtained show high heating loads to create wall jets next to all heated surfaces that significantly alter the structure of the turbulent flow. Results generated on effects of heat loads on the mean and fluctuating components of velocity and temperature, turbulent kinetic energy, the anisotropy of the Reynolds stresses, and velocity-temperature correlations can be used to improve existing RANS models. [ABSTRACT FROM AUTHOR]

Ga-free InAs/InAsSb type-II superlattice structures grown on GaSb substrates have demonstrated high performance for mid-wave infrared applications. However, realisation of long wavelength infrared photodetectors based on this material system still presents challenges, especially in terms of reduced quantum efficiency. This reduction is due, in part, to the increased type-II superlattice period required to attain longer wavelengths, as thicker periods decrease the wave-function overlap for the spatially separated quantum wells. One way to improve long wavelength infrared performance is to modify the type-II superlattice designs with a shorter superlattice period for a given wavelength, thereby increasing the wave-function overlap and the resulting optical absorption. Long wavelength infrared epitaxial structures with reduced periods have been realised by shifting the lattice constant of the type-II superlattice from GaSb to AlSb. Alternatively, epitaxial growth on substrates with orientations different than the traditional (100) surface presents another way for superlattice period reduction. In this work, the authors evaluate the performance of long wavelength infrared type-II superlattice detectors grown by molecular beam epitaxy using two different approaches to reduce the superlattice period: first, a metamorphic buffer to target the AlSb lattice parameter, and second, structures lattices matched to GaSb using substrates with different orientations. The use of the metamorphic buffer enabled a ~30% reduction in the superlattice period compared to reference baseline structures, maintaining a high quantum efficiency, but with the elevated dark current related to defects generated in the metamorphic buffer. Red-shift in a cut-off wavelength obtained from growths on highindex substrates offers a potential path to improve the infrared photodetector characteristics. Focal plane arrays were fabricated on (100), (311)A- and (211)B-oriented structures to compare the performance of each approach. [ABSTRACT FROM AUTHOR]

The need for cellular markers that permit a quick and accurate evaluation of a protein's subcellular localization has increased with the surge of new data generated by the Drosophila genome project. In this report, we present three ubiquitously expressed Drosophila transgenes that expressed a green fluorescent protein variant (enhanced yellow fluorescent protein) that has been targeted to different intracellular membrane targets: the Golgi apparatus, mitochondria, and endoplasmic reticulum. These markers serve as an internal standard for characterizing a protein's subcellular localization or as a means of tracking the dynamics of intracellular organelles during normal or abnormal cellular or developmental processes. We have also examined fixation artifacts using these constructs to illustrate the effects that fixation and permeabilization have on intracellular membrane organization.

Consumption habits have become an integral component in new Keynesian models. However, consumption habits can be modeled in a host of different ways and this diversity is reflected in the literature. I examine whether different approaches to modeling consumption habits have important implications for business cycle behavior. Using a standard New Keynesian business cycle model, I show that, to a first-order log-approximation, the consumption Euler equation associated with the additive functional form for habit formation encompasses the multiplicative function form. Empirically, I show that whether consumption habits are internal or external has little effect on the model's business cycle characteristics. JEL codes: E52, E58 Keywords: habit formation, business cycles., CONSUMPTION HABITS ARE a key component in modern New Keynesian business cycle models. (1) They are relied on to explain movements in aggregate consumption data and to generate the 'hump-shaped' [...]

Background. Previous studies have identified relationships between subcutaneous abdominal fat (SAF), visceral fat (VF), and insulin resistance. In addition, lower muscle attenuation and decreased adiponectin have also been associated with insulin resistance. Methods. In order to define these relationships within a group of older, obese adults, we studied 48 individuals (20 men; 71 [+ or -] 1 years and 28 women; 65 [+ or -] 1 years) who underwent a single, hyperinsulinemic, euglycemic clamp procedure, computed tomography scan at the L4-L5 level, and whole-body plethysmography or dual energy x-ray absorptiometry. Endogenous glucose production (basal glucose Ra) was also measured at baseline and during the clamp procedure using an infusion of [6,[6.sup.2][H.sub.2]] glucose. Results. Mean body mass index (BMI; 31 [+ or -] 1 kg/[m.sup.2]) and glycosylated hemoglobin Alc (HbA1c; 5.7 [+ or -] 0.1%) levels were not significantly different between men and women. In men, there was an inverse relationship between SAF and insulin-stimulated glucose disposal (ISGD) (r= -.60, p = .01). In addition, there was a trend between thigh muscle attenuation and ISGD in men (r = .41, p = .07). Adiponectin was associated with ISGD in men (r = .46, p = .04) and women (r = .48, p = .01). There were no significant relationships between body fat distribution and basal glucose [R.sub.a] in men or women, and no relationships between triglycerides and glucose metabolism. Conclusions. Our results indicate that (i) SAF was negatively associated with ISGD in men, (ii) thigh muscle attenuation demonstrated a trend toward ISGD in men, and (iii) adiponectin was associated with ISGD in men and women.

Algorithms that solve for optimal simple monetary policy rules in rational expectations models are presented. A comparative study of the model with precommitment and discretion showed that time-inconsistency did not affect economic outcomes in the Rudebusch model, but was important in Fuhrer-Moore model.

A study involving the structural understanding of monetary policy by estimating a policy maker's function, and by deriving the conditions under which the parameters in a policy maker's policy objective function can be identified and estimated is presented.