1,721,073 research outputs found
Solution-based oxide films for clean energy applications
Full text linkThe reduction of the energy consumption is currently one of the most critical global challenges, which applies to an extensive number of fields. Heating, ventilation, and air conditioning (HVAC) systems account for up to 20% of the global energy consumed by developed countries. Several HVAC systems rely on condensation heat exchangers, which harness the liquid-vapor phase change for the thermal transfer. Considering the air conditioning (AC) systems, the challenge posed by the systemic cooling poverty underscores the necessity of exploring new approaches with respect to conventional AC systems. An alternative and/or complementary solution is offered by thermochromic smart windows, which exhibit a passive modulation of the solar irradiation without requiring active energy inputs for activation.
In addition to HVAC systems, the shortage of drinkable water poses an additional challenge affecting the global energy consumption. According to the FAO reports, nearly one-sixth of the world’s entire population are daily plagued from severe water scarcity. Among the various approaches, from solar-driven desalination plants to distillation systems for contaminated water, a promising solution is offered by the vapor collection from humid air. As emerges from these reports, even slight improvements in the efficiency of heat exchangers, water collectors, and smart windows could have a powerful impact on reducing the massive global energy consumption. The optimization of the latter three applications has been the focus of this doctoral research.
Several oxide coatings were prepared following a chemical solution deposition (CSD) method, which will be introduced in Chapter 1. In the first experimental part (Chapter 2), the functional properties of hybrid silica (SiO2) coatings were tuned and exploited to control the efficiency of heat exchangers and moisture collectors. In the second part (Chapters 3-6), vanadium dioxide (VO2) thin films were employed for the fabrication of thermochromic smart windows. The temperature-dependent nature of the optical and electrical properties of VO2 provides a passive means to modulate the solar irradiation without relying on active energy inputs. The numerous parameters influencing the CSD method were optimized in Chapter 4, from which homogeneous and thermochromic VO2 thin films were obtained.
Concerning the latter material, a currently unsolved challenge involves the reduction of the crystallization temperature below 400°C. In Chapter 5, an unconventional nanosecond pulsed laser annealing method was exploited to remarkably reduce the crystallization temperature of VO2 thin films. Additional challenges regarding VO2-based smart windows pertain to two essential features that must be ensured for real-world application, namely the transmission of visible light and the resistance against weatherability. Both challenges were addressed in Chapter 6, though the combination of VO2 with titanium dioxide (TiO2) and hybrid SiO2 coatings in bilayer configurations.
In the final Chapter 7, the efficiency of VO2 thin films towards H2 gas detection was considered. The latter is becoming increasingly important in the field of decarbonization and implementation of low-impact renewable energy. Different morphologies and degrees of crystallinity were considered by tuning the laser-annealing and conventional furnace-annealing parameters, and the latter impact on the H2 gas sensing efficiency was investigated
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
Pathogenesis Of Portal Vein Thrombosis In Liver Cirrhosis: The Role of the ADAMTS13/VWF Unbalance
Full text linkIncreasing evidence shows a potential role of ADAMTS13 deficiency as a
risk factor for the high prevalence of portal vein thrombosis (PVT) in cirrhotic
patients. This deficiency, due to myofibroblastic transformation of hepatic
stellate cells (HSCs), the source of ADAMTS13, is responsible for the prevalence
of ultra large molecular weight multimers of von Willebrand factor (UL-VWF)
in the hepatic microcirculation. This phenomenon would favor the prohaemostatic
function of VWF, which, together with an elevation of coagulation
FVIII, which is associated to VWF, could sustain microcirculatory thrombosis
in the liver. These phenomena, triggering an increase of the intra-hepatic
pressure, would cause a slowdown of the portal flow, favoring the occurrence
of PVT. Although this scenario is justified by retrospective observational
clinical studies, it will be mandatory to clarify the ADAMTS13 expression in
HSCs associated with the activity of plasma ADAMTS13 in different stage of
liver diseases. Hence, a prospective clinical trial (ClinicalTrials.gov Identifier:
NCT03322696) is ongoing to unravel the linkage between all the actors involved
in the complex phenomenon of PVT occurring in cirrhosi
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
Congenital prothrombin deficiency: an update
No full textProthrombin (factor II [FII]) deficiency is a rare inherited coagulation disorder, having a
prevalence of approximately 1 in 2,000,000. Two phenotypes can be distinguished: (1)
true hypoprothrombinemia (type I deficiency), characterized by concomitantly low
levels of the zymogen antigen; and (2) dysprothrombinemia (type II deficiency),
characterized by the normal or near-normal synthesis of a dysfunctional protein. In
the latter case, recent studies showed that particular mutations in the catalytic domain
of active thrombin can even impair the enzyme interaction with antithrombin, favoring
thromboembolic diseases. In some cases, hypoprothrombinemia associated with
dysprothrombinemia was also described in compound heterozygous defects. Prothrombin
is essential for the development of mammalian organisms. No living patient with
undetectable plasma prothrombin has been reported to date. Prothrombin is encoded
by a 21 kb gene located on chromosome 11 and containing 14 exons. Thirty-nine
different mutations have been identified and characterized in prothrombin deficiency.
Many of these are present in the catalytic site, whereas some involve regulatory
domains, such as the anion-binding exosite I, the Naþ-binding loop, and the light Achain.
Most hypoprothrombinemia-associated mutations are missense, but nonsense
mutations leading to stop codons and one single nucleotide deletion have also been identified. Finally, recent developments in the therapy of congenital prothrombin
deficiency 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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