1,721,331 research outputs found
Expression of Alpha-1-Antitrypsin in T-cell lymphocytes
No full textI have studied immunoblastic T-cell lymphoma and enteropathy associated T-cell lymphoma using immunohistochemical techniques for the demonstration of AlAT. Cytoplasmic staining for AlAT is present in the malignant cells of both types of T-cell neoplasm which also express CD30 and CD25. Peripheral blood T-lymphocytes on stimulation with mitogen also show granular cytoplasmic expression of AlAT. Time course studies show that this parallels the expression of CD30 and CD25, markers of lymphoid activation. AlAT expression appears therefore to be associated with activation in T-cells. Further studies of subfractionated T-lymphocytes suggest that the expression of AlAT on activation is not restricted to an individual lymphocyte subset. This study demonstrates AlAT mRNA in monocytes, granulocytes and lumphocytes stimulated with con-A, using synthetic oligonucleotide gene probes. Our results confirm AlAT synthesis by these cells. These cells also express exons A and B, exons not expressed in the hepatocyte. Using probes for the individual exons we have demonstrated alternative splicing of exon B in monocytes and lymphocytes.</p
High-Temperature Cavity Receiver Integrated with a Short-Term Storage System for Solar MGTs: Heat Transfer Enhancement
No full textDish-Micro Gas Turbines (MGTs) can be promising systems for power production at small-scale by concentrated solar radiation. Several high-temperature solar receivers have been already designed for such plants, however, nowadays, none of them can assure the proper thermal inertia to level the effects of solar radiation fluctuations on engine performance and safety. In this paper, a solar receiver integrated with a short-term storage system based on high-temperature Phase-Change Materials (PCMs), is proposed. On the basis of a previous preliminary component design and analysis, the receiver geometry has been modified to improve storage capability and heat transfer to the working fluid, reducing temperatures on the irradiated surface making them compatible with material properties and reducing also temperature gradients inside the PCM. Six different geometries, varying length, opening and shape of a front cavity have been analyzed by means of CFD methods. All the configurations have shown a satisfactory behavior in terms of working fluid outlet temperature, storage capabilities and maximum temperatures reached on the surface and inside the receiver. In particular, among them, three geometries can be considered the most promising ones
Development of a solar cavity receiver with a short-term storage system
No full textThe technological progress carried out in the development of high-temperature materials has led to the design of new concentrated solar power plants, like Dish-Micro Gas Turbines (Dish-MGTs). This study proposes a novel cavity receiver for small-scale Dish-MGT plants with a phase-change material storage system integrated inside the receiver container. Such a storage system provides a proper thermal inertia to the component, to level the effects of short-term solar radiation fluctuations which can reduce plant performance and, in the worst cases, damage seriously the MGT. In the paper, results related to CFD steady-state and transient (charge and discharge storage phases) analyses are presented and discussed
Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver
No full textSolar Dish Micro Gas Turbine (MGT) systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures with concentrated solar radiations, which strongly vary with time. This paper deals with the design and the analysis of a novel solar receiver integrated with a short-term storage system based on Phase Change Materials to prevent sudden variations in the maximum temperature of the MGT working fluid. Particularly, the charge and discharge behavior of the storage system was analyzed by means of Computational Fluid Dynamic methods to evaluate the potentiality of the concept and the component capabilities. Achieved results were highly satisfactory: the novel solar receiver has a good thermal inertia and can prevent relevant fluctuations in the working fluid temperature for 20–30 min
Thermal analysis of Mg 2 Si and Fe 2 Si 5 phase change materials for Dish-MGT plants
No full textFor Concentrated Solar Power plants, the storage of thermal energy at high temperature is a critical issue. This paper deals with the application of a Phase Change Material integrated in the solar receiver of the Dish-Micro Gas Turbine (DMGT) for the mitigation of solar radiation fluctuation effects on DMGT performance. For this application, the PCM should have a melting temperature between 900 and 1200°C. Even if some promising materials are suggested in literature, the properties of most of them are not fully characterised in the working temperature range. Therefore, this paper presents the experimental results of the thermal analysis of two high-temperature metallic PCMs (Mg 2 Si and Fe 2 Si 5 ). Thermal diffusivity, specific heat capacity and thermal conductivity have been determined using Simultaneous Thermal Analysis (STA) and Laser Flash Analysis (LFA) apparatuses. The thermal expansion behaviour of the samples has been determined up to 1000°C. Furthermore, the compatibility of the PCM samples with the Silicon carbide (SiC) has been also studied up to 1000°C
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
High-temperature solar receiver integrated with a short-term storage system
No full textSmall-Scale Concentrated Solar Power Plants could have a potential market for off-grid applications in rural contexts with limited access to the electrical grid and favorable environmental characteristics. Some Small-Scale plants have already been developed, like the 25-30 kWe Dish-Stirling engine. Other ones are under development as, for example, plants based on Parabolic Trough Collectors coupled with Organic Rankine Cycles. Furthermore, the technological progress achieved in the development of new small high-temperature solar receiver, makes possible the development of interesting systems based on Micro Gas Turbines coupled with Dish collectors. Such systems could have several advantages in terms of costs, reliability and availability if compared with Dish-Stirling plants. In addition, Dish-Micro Gas Turbine systems are expected to have higher performance than Solar Organic Rankine Cycle plants. The present work focuses the attention on some challenging aspects related to the design of small high-temperature solar receivers for Dish-Micro Gas Turbine systems. Natural fluctuations in the solar radiation can reduce system performance and damage seriously the Micro Gas Turbine. To stabilize the system operation, the solar receiver has to assure a proper thermal inertia. Therefore, a solar receiver integrated with a short-term storage system based on high-temperature phase-change materials is proposed in this paper. Steady-state and transient analyses (for thermal storage charge and discharge phases) have been carried out using the commercial CFD code Ansys-Fluent. Results are presented and discussed
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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