scholarly journals Hydrogels with Gigantic Thermopower for Low-grade Heat Harvesting

2021 ◽  
Author(s):  
Kuan Sun ◽  
Yongjie He ◽  
Qi Zhang ◽  
Hanlin Cheng ◽  
Yang Liu ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Large Scale ◽  
Great Promise ◽  
Physical Parameters ◽  
Low Grade ◽  
Te Material ◽  
Mobile Ions ◽  
Low Grade Heat ◽  
The Relationship

Abstract Harvesting energy from the environment to power the self-sustained systems has long been desired1,2. Ionic thermoelectric (i-TE) material with mobile ions as charge carriers has the advantage to generate large thermal voltages at low operating temperatures3-5. Recent works improved the thermopower substantially by modifying the polymer matrix of the i-TE hydrogels6-9. But the mobile ions have not been systematically studied in the context of i-TE hydrogels. This study highlights the role of ions in i-TE hydrogels employing a polyvinyl alcohol (PVA) polymer matrix and a number of ion providers, e.g. KOH, KNO3, KCl, KBr, NaI, KI, and CsI. The relationship between the intrinsic physical parameters of the ion and the thermoelectric performance is established, indicating electronegativity of the cation and the ability to influence the hydrogen bond by the anion are two crucial factors. Among these i-TE hydrogels, PVA/CsI hydrogel exhibits the largest ionic Seebeck coefficient, reaching 52.9 mV K-1, which is the greatest of all i-TE materials reported till date. In addition, PVA/NaI hydrogel exhibits excellent TE properties, with a record ZT value of 5.09 at room temperature. This flexible, inexpensive hydrogel that compatible with large-scale manufacturing shows great promise for low-grade thermal energy harvesting.

Pots on mats: mat-impressed salt-extraction pottery at Chalcolithic Provadia-Solnitsata, Bulgaria

Antiquity ◽  
2021 ◽  
pp. 1-16
Author(s):  
Mila Andonova ◽  
Vassil Nikolov
Keyword(s):  
Material Culture ◽  
Large Scale ◽  
Raw Materials ◽  
Salt Production ◽  
Production And Consumption ◽  
Late Chalcolithic ◽  
South Eastern Europe ◽  
Materials Used ◽  
The Relationship

Evidence for both basket weaving and salt production is often elusive in the prehistoric archaeological record. An assemblage of Middle–Late Chalcolithic pottery from Provadia-Solnitsata in Bulgaria provides insight into these two different technologies and the relationship between them. The authors analyse sherds from vessels used in large-scale salt production, the bases of which bear the impression of woven mats. This analysis reveals the possible raw materials used in mat weaving at Provadia-Solnitsata and allows interpretation of the role of these mats in salt production at the site. The results illustrate how it is possible to see the ‘invisible’ material culture of prehistoric south-eastern Europe and its importance for production and consumption.

scholarly journals COVID-19 and the importance of space in entrepreneurship research and policy

2020 ◽  
Vol 38 (8) ◽  
pp. 697-710 ◽  
Author(s):  
Steffen Korsgaard ◽  
Richard A Hunt ◽  
David M Townsend ◽  
Mads Bruun Ingstrup
Keyword(s):  
Economic System ◽  
Large Scale ◽  
Local Economies ◽  
Spatial Perspective ◽  
Entrepreneurship Research ◽  
Digital Platform ◽  
The Face ◽  
The Relationship ◽  
Research And Policy

Given the COVID-19 crisis, the importance of space in the global economic system has emerged as critical in a hitherto unprecedented way. Even as large-scale, globally operating digital platform enterprises find new ways to thrive in the midst of a crisis, small and medium-sized enterprises (SMEs) nestled in local economies have proven to be fragile to shocks, causing countless local economies to unravel in the face of severe challenges to survival. Here, we discuss the role of entrepreneurship in re-building local economies that are more resilient. Specifically, we take a spatial perspective and highlight how the COVID-19 crisis has uncovered problems in the current tendency for thin contextualisation and promotion of globalisation. Based on this critique, we outline new perspectives for thinking about the relationship between entrepreneurship, resilience and local economies. Here, a particular emphasis is given to resilience building through deeply contextualised policies and research, localised flows of products and labour, and the diversification of local economies.

scholarly journals The Supershell-Molecular Cloud Connection in the Milky Way and Beyond

2012 ◽  
Vol 8 (S292) ◽  
pp. 83-86
Author(s):  
J. R. Dawson ◽  
N. M. McClure-Griffiths ◽  
Y. Fukui ◽  
J. Dickey ◽  
T. Wong ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Molecular Clouds ◽  
Large Scale ◽  
Milky Way ◽  
Observational Evidence ◽  
Cloud Formation ◽  
Stellar Feedback ◽  
The Relationship ◽  
Global Contribution

AbstractThe role of large-scale stellar feedback in the formation of molecular clouds has been investigated observationally by examining the relationship between Hi and 12CO(J = 1−0) in supershells. Detailed parsec-resolution case studies of two Milky Way supershells demonstrate an enhanced level of molecularisation over both objects, and hence provide the first quantitative observational evidence of increased molecular cloud production in volumes of space affected by supershell activity. Recent results on supergiant shells in the LMC suggest that while they do indeed help to organise the ISM into over-dense structures, their global contribution to molecular cloud formation is of the order of only ∼ 10%.

scholarly journals The role of anatomical connection strength for interareal communication in macaque cortex

2020 ◽  
Author(s):  
Julien Vezoli ◽  
Martin Vinck ◽  
Conrado A. Bosman ◽  
Andre M. Bastos ◽  
Christopher M Lewis ◽  
...  
Keyword(s):  
Large Scale ◽  
Functional Organization ◽  
Brain Regions ◽  
Connection Strength ◽  
Non Invasive ◽  
Large Scale Networks ◽  
Invasive Techniques ◽  
The Relationship ◽  
Anatomical Connection

What is the relationship between anatomical connection strength and rhythmic synchronization? Simultaneous recordings of 15 cortical areas in two macaque monkeys show that interareal networks are functionally organized in spatially distinct modules with specific synchronization frequencies, i.e. frequency-specific functional connectomes. We relate the functional interactions between 91 area pairs to their anatomical connection strength defined in a separate cohort of twenty six subjects. This reveals that anatomical connection strength predicts rhythmic synchronization and vice-versa, in a manner that is specific for frequency bands and for the feedforward versus feedback direction, even if interareal distances are taken into account. These results further our understanding of structure-function relationships in large-scale networks covering different modality-specific brain regions and provide strong constraints on mechanistic models of brain function. Because this approach can be adapted to non-invasive techniques, it promises to open new perspectives on the functional organization of the human brain.

scholarly journals Key Role of the Dispersion of Carbon Nanotubes (CNTs) within Epoxy Networks on their Ability to Release

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2530
Author(s):  
Maxime Pras ◽  
Jean-François Gérard ◽  
Luana Golanski ◽  
Guilhem Quintard ◽  
Jannick Duchet-Rumeau
Keyword(s):  
Polymer Matrix ◽  
Interfacial Strength ◽  
Advanced Materials ◽  
Mechanical Reinforcement ◽  
Rheological Analysis ◽  
Polymerization Kinetic ◽  
The Matrix ◽  
Dispersion State ◽  
The Relationship

Carbon nanotube (CNT)-reinforced nanocomposites represent a unique opportunity in terms of designing advanced materials with mechanical reinforcement and improvements in the electrical and thermal conductivities. However, the toxic effects of these composites on human health have been studied, and very soon, some regulations on CNTs and on composites based on CNTs will be enacted. That is why the release of CNTs during the nanocomposite lifecycle must be controlled. As the releasing depends on the interfacial strength that is stronger between CNTs and polymers compared to CNTs in a CNT agglomerate, two dispersion states—one poorly dispersed versus another well dispersed—are generated and finely described. So, the main aim of this study is to check if the CNT dispersion state has an influence on the CNT releasing potential in the nanocomposite. To well tailor and characterize the CNT dispersion state in the polymer matrix, electronic microscopies (SEM and TEM) and also rheological analysis are carried out to identify whether CNTs are isolated, in bundles, or in agglomerates. When the dispersion state is known and controlled, its influence on the polymerization kinetic and on mechanical properties is discussed. It appears clearly that in the case of a good dispersion state, strong interfaces are generated, linking the isolated nanotubes with the polymer, whereas the CNT cohesion in an agglomerate seems much more weak, and it does not provide any improvement to the polymer matrix. Raman spectroscopy is relevant to analyze the interfacial properties and allows the relationship with the releasing ability of nanocomposites; i.e., CNTs poorly dispersed in the matrix are more readily released when compared to well-dispersed nanocomposites. The tribological tests confirm from released particles granulometry and observations that a CNT dispersion state sufficiently achieved in the nanocomposite avoids single CNT releasing under those solicitations.

scholarly journals Association between interleukin-8 −251A/T polymorphism and the risk of tuberculosis: A meta-analysis

2020 ◽  
Vol 48 (5) ◽  
pp. 030006052091787
Author(s):  
Qin Hu ◽  
Haibo Hua ◽  
Lihong Zhou ◽  
Xingwu Zou
Keyword(s):  
Confidence Intervals ◽  
Large Scale ◽  
Meta Analysis ◽  
Recessive Model ◽  
Interleukin 8 ◽  
Dominant Model ◽  
Subgroup Analyses ◽  
Relationship Of ◽  
The Relationship

Objective The relationship between interleukin-8 ( IL8) −251A/T polymorphism and tuberculosis (TB) risk remains controversial. Therefore, the present meta-analysis was performed by retrieving relevant studies from the available literature. Methods We comprehensively searched three databases to identify eligible literature on the relationship of IL8 −251A/T polymorphism with TB risk, calculated pooled odds ratios (OR) with 95% confidence intervals (CI), and subsequent evaluated the heterogeneity and publication bias. Results We found that IL8 −251A/T polymorphism increased TB risk (AA vs. TT: OR = 2.86, 95%CI: 1.46–5.60; AT vs. TT: OR = 1.64, 95%CI: 1.15–2.34; dominant model: OR = 1.88, 95%CI: 1.24–2.86; recessive model: OR = 1.77, 95%CI: 1.17–2.69). Subgroup analyses based on race revealed that the IL8 −251A/T polymorphism might be associated with the risk of TB in African but not Asian individuals. Conclusion The IL8 −251A/T polymorphism might be related to the risk of TB. Nevertheless, large-scale studies should be performed to confirm the role of IL8 −251A/T polymorphism on TB risk.

scholarly journals Perform or wither: role of water users' associations in municipalities of Nepal

Water Policy ◽  
2019 ◽  
Vol 22 (S1) ◽  
pp. 90-106
Author(s):  
Sreoshi Singh ◽  
Krity Shrestha ◽  
Menaka Hamal ◽  
Anjal Prakash
Keyword(s):  
Large Scale ◽  
Water Systems ◽  
Low Grade ◽  
Water Shortages ◽  
Water Users ◽  
Two Cities ◽  
Long Time ◽  
User Groups ◽  
Supply Systems

Abstract In Nepal, water institutions have played a very significant role, and in Tansen and Damauli, the presence of user groups has indicated that proper management of water can help people avert critical water shortages. However, although in both Tansen and Damauli the user groups have been operating for a long time, their performances vary. In Tansen, infrastructural constraints tend to throw up challenges, although operational hazards associated with the supply systems are no less threatening. Moreover, there is large-scale corruption in the systems' upkeep and maintenance, allowing low grade vendors to operate in place of readily available efficient institutions. In Damauli, the systems have been rather perfectly managed, except for minor glitches from time to time. Funding has been good and community bonding has paid off. This paper delves into the community-managed water systems in the two cities and how the performance varies across them and the factors that play a role.

scholarly journals The role of transient resonances for ultra-fast imaging of single sucrose nanoclusters

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Phay J. Ho ◽  
Benedikt J. Daurer ◽  
Max F. Hantke ◽  
Johan Bielecki ◽  
Andre Al Haddad ◽  
...  
Keyword(s):  
Large Scale ◽  
Computational Models ◽  
Great Promise ◽  
Single Shot ◽  
Diffractive Imaging ◽  
Transient Phenomena ◽  
X Ray ◽  
Water Window ◽  
Ultrafast Imaging

AbstractIntense x-ray free-electron laser (XFEL) pulses hold great promise for imaging function in nanoscale and biological systems with atomic resolution. So far, however, the spatial resolution obtained from single shot experiments lags averaging static experiments. Here we report on a combined computational and experimental study about ultrafast diffractive imaging of sucrose clusters which are benchmark organic samples. Our theoretical model matches the experimental data from the water window to the keV x-ray regime. The large-scale dynamic scattering calculations reveal that transient phenomena driven by non-linear x-ray interaction are decisive for ultrafast imaging applications. Our study illuminates the complex interplay of the imaging process with the rapidly changing transient electronic structures in XFEL experiments and shows how computational models allow optimization of the parameters for ultrafast imaging experiments.

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