933 research outputs found

    Active heat exchange system development for latent heat thermal energy storage

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    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application. Two concepts selected for hardware development are a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. Suitable phase change material (PCM) storage media with melting points in the temperature range of interest (250 C to 400 C) were investigated. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24/5 NaCl-55.0MgCl 2% by wt.), with a nominal melting point of 385 C

    Active heat exchange system development for latent heat thermal energy storage

    Get PDF
    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW sub t storage for 6 hours). Two concepts were selected for hardware development: (1) a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and (2) a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which was nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design

    Why is apoptosis important to clinicians?

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    Interprovincial differences in the rates of minor crimes of violence and related disorders in New Zealand 1853-1930: part 2

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    Der vorliegende Beitrag diskutiert einige methodologische Probleme, die sich in der historischen Sozialforschung durch den Vergleich allgemeiner sozialer Variablen über zwei oder mehr Gebiete ergeben. Die Autoren beschreiben, welche statistischen Modelle und Verfahren hier zur Verfügung stehen. Vor- und Nachteile der einzelnen Verfahren werden gegeneinander abgewogen. Anhand der Daten zu einem früheren Beitrag in der HSR (Haslett/Fairburn,1990,Bd.1) zur Kleinkriminalität in 9 Destrikten Neuseelands demonstrieren die Autoren die Möglichkeiten der Faktorenanalyse hinsichtlich der Ausgangsfragestellung. (pmb)'The problem of comparing historical data with common variables from two or more distinct locations remains an open question in historical studies. The issues of formulating suitable historical models and comparing them, using appropriate statistical models and techniques, are the topics of this paper. These matters are first discussed in general and a number of possible techniques outlined in concept. The advantages and disadvantages of each are summarised. The question of distinguishing between differences of structure and differences of degree, in the presence of measurement error, is then considered in greater detail with reference to factor analysis and the New Zealand provincial data base, 1853-1930.' (author's abstract

    Interprovincial differences in the rates of minor crimes of violence and related disorders in New Zealand, 1853-1930: part 1

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    Zwischen 1853 und 1930 wurde Neuseeland rapide durch hauptsächlich aus Großbritannien stammende Einwanderer kolonialisiert. Gegen Ende der 1870er Jahre sank die Rate der Kleinkriminalität (Tätlichkeiten, Trunkenheitsdelikte, Alkoholmißbrauch) dramatisch. Der vorliegende Beitrag geht der Frage nach, ob die Ursachen dieser 'Ordnungswidrigkeiten' für alle 9 Distrikte Neuseelands die gleichen sind. Durch eine Faktorenanalyse und ein Modell von 22 Variablen kann die Autorin für jede Provinz je eine spezifische kausale Struktur herausarbeiten. Trotz dieser Differenzen läßt sich jedoch für die 'Kolonie' ein spezifisch britischer einheitlicher Lebensstil identifizieren. (pmb)'Between 1853 and 1930 New Zealand was rapidly colonised by white settlers most of whom were British immigrants. From about the late 1870s their per capita rates of minor assaults drunkenness convictions, spirits consumption, and civil suits fell dramatically. The paper asks whether the causal structure underlying these 'disorders' was the same in every one of New Zealand's nine provincial districts. Even though New Zealand was comparatively homogenous in ethnic and cultural terms, the character of its provincial districts varied substantially in respect to other criteria such as policing, population size, level of economic development, urbanization, industrialization and so forth. To determine if the same explanatory model fits each of the nine provinces, the paper systematically applies two forms of factor analysis to a matrix of twenty two variables in each province. The paper finds that every province had a causal structure which differed in kind from that operating in the other provinces. However, these differences were not fundamental in type.' (author's abstract

    Evidence for prelocalization of cytoplasmic factors affecting gene activation in early embryogenesis

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    Differentiation begins early in embryogenesis as different genes become active in different cells. Within the closed system of the early embryo, equal genomes thus direct the creation of diverse cell types. Though the nuclei of these cells contain complete copies of the same genome,(1,2) the nucleoplasmic and cytoplasmic environments of these genomes are not the same, as a result of the distribution of cleavage nuclei into diverse areas of egg cytoplasm early in the cleavage process. In some cases the fate of these nuclei, i.e., the type of differentiated cell to which they or their descendants give rise, has been seen to depend on the area of cytoplasm in which they come to lie

    Does ChatGPT resemble humans in language use?

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    Large language models (LLMs) and LLM-driven chatbots such as ChatGPT have shown remarkable capacities in comprehending and producing language. However, their internal workings remain a black box in cognitive terms, and it is unclear whether LLMs and chatbots can develop humanlike characteristics in language use. Cognitive scientists have devised many experiments that probe, and have made great progress in explaining, how people process language. We subjected ChatGPT to 12 of these experiments, pre-registered and with 1,000 runs per experiment. In 10 of them, ChatGPT replicated the human pattern of language use. It associated unfamiliar words with different meanings depending on their forms, continued to access recently encountered meanings of ambiguous words, reused recent sentence structures, reinterpreted implausible sentences that were likely to have been corrupted by noise, glossed over errors, drew reasonable inferences, associated causality with different discourse entities according to verb semantics, and accessed different meanings and retrieved different words depending on the identity of its interlocutor. However, unlike humans, it did not prefer using shorter words to convey less informative content and it did not use context to disambiguate syntactic ambiguities. We discuss how these convergences and divergences may occur in the transformer architecture. Overall, these experiments demonstrate that LLM-driven chatbots like ChatGPT are capable of mimicking human language processing to a great extent, and that they have the potential to provide insights into how people learn and use language

    Increased gastrin-releasing peptide (GRP) receptor expression in tumour cells confers sensitivity to [Arg6,D-Trp7,9,NmePhe8]-substance P (6-11)-induced growth inhibition.

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    [Arg(6),D-Trp(7,9),N(me)Phe(8)]-substance P (6-11) (SP-G) is a novel anticancer agent that has recently completed phase I clinical trials. SP-G inhibits mitogenic neuropeptide signal transduction and small cell lung cancer (SCLC) cell growth in vitro and in vivo. Using the SCLC cell line series GLC14, 16 and 19, derived from a single patient during the clinical course of their disease and the development of chemoresistance, it is shown that there was an increase in responsiveness to neuropeptides. This was paralleled by an increased sensitivity to SP-G. In a selected panel of tumour cell lines (SCLC, non-SCLC, ovarian, colorectal and pancreatic), the expression of the mitogenic neuropeptide receptors for vasopressin, gastrin-releasing peptide (GRP), bradykinin and gastrin was examined, and their sensitivity to SP-G tested in vitro and in vivo. The tumour cell lines displayed a range of sensitivity to SP-G (IC(50) values from 10.5 to 119 microM). The expression of the GRP receptor measured by reverse transcriptase-polymerase chain reaction, correlated significantly with growth inhibition by SP-G. Moreover, introduction of the GRP receptor into rat-1A fibroblasts markedly increased their sensitivity to SP-G. The measurement of receptor expression from biopsy samples by polymerase chain reaction could provide a suitable diagnostic test to predict efficacy to SP-G clinically. This strategy would be of potential benefit in neuropeptide receptor-expressing tumours in addition to SCLC, and in tumours that are relatively resistant to conventional chemotherapy
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