976 research outputs found
Thermodynamic Measurements Using the Knudsen Cell Technique
The Knudsen cell technique has been used for over a century and is a valuable tool for measurement of vapor pressures and thermodynamic properties. It is based on a small enclosure (~1 cm long x 1 cm diameter) in which a condensed phase/vapor equilibria can be established. A small (<1 mm) orifice on the cell allows sampling of the vapor via a variety of techniques including weight loss, torsion effusion, target collection, and mass spectrometry. Many excellent measurements based on these methods have been reported. However in order to obtain reliable measurements, a variety of factors must be considered. They include proper cell material selection, accurate and uniform temperature control and measurement, and proper sampling of the vapor. Each of these factors are discussed in detail in this chapter. Typically these studies are conducted at high temperatures and it is a challenge to select an inert container material. Recommended materials are discussed and in some cases the container may be used as part of the system under study. Temperature control and measurement is perhaps the most important issue. In most systems, the furnace must be compact yet there can be no temperature gradient in the cell. Temperatures are measured with either a thermocouple or pyrometer and the relative advantages of each are discussed. Sampling method considerations depend on the particular technique. It is essential that all of the vapor or a representative portion of the vapor be sampled. The distribution of the effusate from a Knudsen cell is discussed and sampling positions discussed. Mass spectrometry is often used to study the effusing vapor and the relations between ion current and vapor pressure are discussed
A Senior Care Facility in Milan, Minnesota: Survey Analysis and Recommendations
In 2004, the Center for Small Towns worked with the City of Milan and the Community Assistantship program through the Center for Urban and Regional Affairs to research the level of need/demand for bringing a senior care facility to the city of Milan, MN,as well as to provide recommendations about future developments.https://digitalcommons.morris.umn.edu/cst/1003/thumbnail.jp
Four problems with global carbon markets: a critical review
This article offers a critique of global carbon markets and trading, with a special focus on the Clean Development Mechanism of the Kyoto Protocol. It explores
problems with the use of tradable permits to address climate change revolving around four areas: homogeneity, justice, gaming, and information. Homogeneity problems arise from the non-linear nature of climate change and sensitivity of emissions, which complicate attempts to calculate carbon offsets. Justice problems involve issues of dependency and the concentration of wealth among the rich, meaning carbon trading often counteracts attempts to reduce poverty. Gaming problems include pressures to promote high-volume, least-cost projects and the
consequences of emissions leakage. Information problems encompass transaction costs related to carbon trading and market participation and the comparatively weak institutional capacity of project evaluators
Age- and stress-associated C. elegans granulins impair lysosomal function and induce a compensatory HLH-30/TFEB transcriptional response.
The progressive failure of protein homeostasis is a hallmark of aging and a common feature in neurodegenerative disease. As the enzymes executing the final stages of autophagy, lysosomal proteases are key contributors to the maintenance of protein homeostasis with age. We previously reported that expression of granulin peptides, the cleavage products of the neurodegenerative disease protein progranulin, enhance the accumulation and toxicity of TAR DNA binding protein 43 (TDP-43) in Caenorhabditis elegans (C. elegans). In this study we show that C. elegans granulins are produced in an age- and stress-dependent manner. Granulins localize to the endolysosomal compartment where they impair lysosomal protease expression and activity. Consequently, protein homeostasis is disrupted, promoting the nuclear translocation of the lysosomal transcription factor HLH-30/TFEB, and prompting cells to activate a compensatory transcriptional program. The three C. elegans granulin peptides exhibited distinct but overlapping functional effects in our assays, which may be due to amino acid composition that results in distinct electrostatic and hydrophobicity profiles. Our results support a model in which granulin production modulates a critical transition between the normal, physiological regulation of protease activity and the impairment of lysosomal function that can occur with age and disease
Divided government and significant legislation: A History of Congress from 1789 to 2010
This article presents and analyzes the most comprehensive database to date of significant acts of Congress—from 1789 to 2010—to test whether divided party control of government affects the number of important acts Congress passes. We find that unified control corresponds with one additional significant act passed per Congress in the nineteenth century and four additional such acts in the twentieth century. However, party control of government cannot explain the broad historical trends in the rate at which Congress passes significant legislation. Nixon in 1969 was far more successful with a Democratic Congress than was McKinley in 1897 with a Republican one
High-fidelity single-shot readout for a spin qubit via an enhanced latching mechanism
The readout of semiconductor spin qubits based on spin blockade is fast but
suffers from a small charge signal. Previous work suggested large benefits from
additional charge mapping processes, however uncertainties remain about the
underlying mechanisms and achievable fidelity. In this work, we study the
single-shot fidelity and limiting mechanisms for two variations of an enhanced
latching readout. We achieve average single-shot readout fidelities > 99.3% and
> 99.86% for the conventional and enhanced readout respectively, the latter
being the highest to date for spin blockade. The signal amplitude is enhanced
to a full one-electron signal while preserving the readout speed. Furthermore,
layout constraints are relaxed because the charge sensor signal is no longer
dependent on being aligned with the conventional (2, 0) - (1, 1) charge dipole.
Silicon donor-quantum-dot qubits are used for this study, for which the dipole
insensitivity substantially relaxes donor placement requirements. One of the
readout variations also benefits from a parametric lifetime enhancement by
replacing the spin-relaxation process with a charge-metastable one. This
provides opportunities to further increase the fidelity. The relaxation
mechanisms in the different regimes are investigated. This work demonstrates a
readout that is fast, has one-electron signal and results in higher fidelity.
It further predicts that going beyond 99.9% fidelity in a few microseconds of
measurement time is within reach.Comment: Supplementary information is included with the pape
Cosmopolitan nationalism and the cultural reach of the white British
In recent years, strong claims have been made for the breakdown of national boundaries and the reformation of national identities in an increasingly interconnected global world – driven in large part by the possibilities and limitations that emerge from an increasingly global media world. It has been argued that new postnational, cosmopolitan subjectivities accompany, enable and feed off globally oriented forms of cultural consumption. This article examines these claims in the light of unusually comprehensive data on the tastes of the white British population collected in a large national sample survey, in-depth interviews and focus groups. By identifying and analysing the geographical spread of the cultural referents of the tastes of the white British we make an empirical assessment of the claims for cosmopolitan identities. We argue that if white British identities are being reformed by processes of globalisation it is, paradoxically, in an increasingly Anglophone direction
Overview of Advanced LIGO Adaptive Optics
This is an overview of the adaptive optics used in Advanced LIGO (aLIGO),
known as the thermal compensation system (TCS). The thermal compensation system
was designed to minimize thermally-induced spatial distortions in the
interferometer optical modes and to provide some correction for static
curvature errors in the core optics of aLIGO. The TCS is comprised of ring
heater actuators, spatially tunable CO laser projectors and Hartmann
wavefront sensors. The system meets the requirements of correcting for nominal
distortion in Advanced LIGO to a maximum residual error of 5.4nm, weighted
across the laser beam, for up to 125W of laser input power into the
interferometer
Overview of Advanced LIGO Adaptive Optics
This is an overview of the adaptive optics used in Advanced LIGO (aLIGO), known as the thermal compensation system (TCS). The TCS was designed to minimize thermally induced spatial distortions in the interferometer optical modes and to provide some correction for static curvature errors in the core optics of aLIGO. The TCS is comprised of ring heater actuators, spatially tunable CO_2
laser projectors, and Hartmann wavefront sensors. The system meets the requirements of correcting for nominal distortion in aLIGO to a maximum residual error of 5.4 nm rms, weighted across the laser beam, for up to 125 W of laser input power into the interferometer
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