higher temperature
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2022 ◽  
Vol 6 (1) ◽  
pp. 1-28
Rongrong Wang ◽  
Duc Van Le ◽  
Rui Tan ◽  
Yew-Wah Wong

At present, a co-location data center often applies an identical and low temperature setpoint for its all server rooms. Although increasing the temperature setpoint is a rule-of-thumb approach to reducing the cooling energy usage, the tenants may have different mentalities and technical constraints in accepting higher temperature setpoints. Thus, supporting distinct temperature setpoints is desirable for a co-location data center in pursuing higher energy efficiency. This calls for a new cooling power attribution scheme to address the inter-room heat transfers that can be up to 9% of server load as shown in our real experiments. This article describes our approaches to estimating the inter-room heat transfers, using the estimates to rectify the metered power usages of the rooms’ air handling units, and fairly attributing the power usage of the shared cooling infrastructure (i.e., chiller and cooling tower) to server rooms by following the Shapley value principle. Extensive numeric experiments based on a widely accepted cooling system model are conducted to evaluate the effectiveness of the proposed cooling power attribution scheme. A case study suggests that the proposed scheme incentivizes rational tenants to adopt their highest acceptable temperature setpoints under a non-cooperative game setting. Further analysis considering distinct relative humidity setpoints shows that our proposed scheme also properly and inherently addresses the attribution of humidity control power.

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 340
Marina I. Voronova ◽  
Darya L. Gurina ◽  
Oleg V. Surov

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polycaprolactone (PHBV/PCL) polymer mixtures reinforced by cellulose nanocrystals (CNCs) have been obtained. To improve the CNC compatibility with the hydrophobic PHBV/PCL matrix, the CNC surface was modified by amphiphilic polymers, i.e., polyvinylpyrrolidone (PVP) and polyacrylamide (PAM). The polymer composites were characterized by FTIR, DSC, TG, XRD, microscopy, BET surface area, and tensile testing. The morphological, sorption, thermal, and mechanical properties of the obtained composites have been studied. It was found out that with an increase in the CNC content in the composites, the porosity of the films increased, which was reflected in an increase in their specific surface areas and water sorption. An analysis of the IR spectra confirms that hydrogen bonds can be formed between the CNC hydroxyl- and the –CO– groups of PCL and PHBV. The thermal decomposition of CNC in the PHBV/PCL/CNC composites starts at a much higher temperature than the decomposition of pure CNC. It was revealed that CNCs can either induce crystallization and the polymer crystallite growth or act as a compatibilizer of a mixture of the polymers causing their amorphization. The CNC addition significantly reduces the elongation and strength of the composites, but changes Young’s modulus insignificantly, i.e., the mechanical properties of the composites are retained under conditions of small linear deformations. A molecular-dynamics simulation of several systems, starting from simplest binary (solvent-polymer) and finishing with multi-component (CNC—polymer mixture—solvent) systems, has been made. It is concluded that the surface modification of CNCs with amphiphilic polymers makes it possible to obtain the CNC composites with hydrophobic polymer matrices.

2022 ◽  
Vol 12 (1) ◽  
Ma-Hsuan Ma ◽  
Erdembayalag Batsaikhan ◽  
Huang-Nan Chen ◽  
Ting-Yang Chen ◽  
Chi-Hung Lee ◽  

AbstractWe report on experimental evidence of non-conversional pairing in In and Sn nanoparticle assemblies. Spontaneous magnetizations are observed, through extremely weak-field magnetization and neutron-diffraction measurements, to develop when the nanoparticles enter the superconducting state. The superconducting transition temperature TC shifts to a noticeably higher temperature when an external magnetic field or magnetic Ni nanoparticles are introduced into the vicinity of the superconducting In or Sn nanoparticles. There is a critical magnetic field and a critical Ni composition that must be reached before the magnetic environment will suppress the superconductivity. The observations may be understood when assuming development of spin-parallel superconducting pairs on the surfaces and spin-antiparallel superconducting pairs in the core of the nanoparticles.

Amreen Bashir ◽  
Peter A. Lambert ◽  
Yvonne Stedman ◽  
Anthony C. Hilton

The survival on stainless steel of ten Salmonella isolates from food factory, clinical and veterinary sources was investigated. Stainless steel coupons inoculated with Salmonella were dried and stored at a range of temperatures and relative humidity (RH) levels representing factory conditions. Viability was determined from 1 to 22 days. Survival curves obtained for most isolates and storage conditions displayed exponential inactivation described by a log-linear model. Survival was affected by environmental temperatures and RH with decimal reduction times (DRTs) ranging from <1 day to 18 days. At 25 °C/15% RH, all isolates survived at levels of 103 to 105 cfu for >22 days. Furthermore, temperatures and RH independently influenced survival on stainless steel; increasing temperatures between 10 °C and 37 °C and increasing RH levels from 30–70% both decreased the DRT values. Survival curves displaying a shoulder followed by exponential death were obtained for three isolates at 10 °C/70% RH. Inactivation kinetics for these were described by modified Weibull models, suggesting that cumulative injury occurs before cellular inactivation. This study highlights the need to control temperature and RH to limit microbial persistence in the food manufacturing environment, particularly during the factory shut-down period for cleaning when higher temperature/humidity levels could be introduced.

Lina Wu ◽  
Amin Elshorbagy ◽  
Md. Shahabul Alam

Abstract Understanding the dynamics of water-energy-food (WEF) nexus interactions with climate change and human intervention helps inform policymaking. This study demonstrates the WEF nexus behavior under ensembles of climate change, transboundary inflows, and policy options, and evaluates the overall nexus performance using a previously developed system dynamics-based WEF nexus model—WEF-Sask. The climate scenarios include a baseline (1986-2014) and near-future climate projections (2021-2050). The approach is demonstrated through the case study of Saskatchewan, Canada. Results show that rising temperature with increased rainfall likely maintains reliable food and feed production. The climate scenarios characterized by a combination of moderate temperature increase and slightly less rainfall or higher temperature increase with slightly higher rainfall are easier to adapt to by irrigation expansion. However, such expansion uses a large amount of water resulting in reduced hydropower production. In contrast, higher temperature, combined with less rainfall, such as SSP370 (2.4 ℃, -6 mm), is difficult to adapt to by irrigation expansion. Renewable energy expansion, the most effective climate change mitigation option in Saskatchewan, leads to the best nexus performance during 2021-2050, reducing total water demand, groundwater demand, greenhouse gas (GHG) emissions, and potentially increasing water available for food production. In this study, we recommend and use food and power production targets and provide an approach to assessing the impacts of hydroclimate and policy options on the WEF nexus, along with suggestions for adapting the agriculture and energy sectors to climate change.

2022 ◽  
Vol 12 (2) ◽  
pp. 721
Ana-Maria Vutan ◽  
Erwin-Christian Lovasz ◽  
Corina-Maria Gruescu ◽  
Carmen Sticlaru ◽  
Elena Sîrbu ◽  

(1) Background: Scoliosis affects about 3% of the population and the number of children diagnosed with this condition is increasing. Numerous studies have been conducted in recent years to observe the effectiveness of rehabilitation specific exercises for this condition. In the present study we aim to observe if symmetrical exercises activate the back muscles in the same way in the case of children with mild scoliosis and those without postural deviations; (2) Methods: We used the thermal imaging camera, which allows a non-invasive, painless investigation that provides real-time information about muscle activity. The study qualitatively assessed muscle activation during exercises. In this study, 30 children were divided into two groups: 15 children diagnosed with mild scoliosis and 15 children without postural deviations; (3) Results: Acquisition of images after each exercise revealed an imbalance in the functioning of the back muscles in children with scoliosis, with areas of higher temperature after exercise on the convexity side of the scoliotic curve. In the second experiment in which children with scoliosis performed the required exercises under the supervision of a physiotherapist, they showed a symmetrical activation of the back muscles on the right and left side of the back; (4) Conclusions: In children without postural deviations, symmetrical exercises activate the muscles equally on the right and left sides of the back. In the case of children with scoliosis, the symmetrical exercises indicated in the rehabilitation programs should be performed only under the supervision of a physiotherapist to properly activate the back muscles.

Robert Freer ◽  
Dursun Ekren ◽  
Tanmoy Ghosh ◽  
Kanishka Biswas ◽  
Pengfei Qiu ◽  

Abstract This paper presents tables of key thermoelectric properties, which define thermoelectric conversion efficiency, for a wide range of inorganic materials. The 12 families of materials included in these tables are primarily selected on the basis of well established, internationally-recognised performance and their promise for current and future applications: Tellurides, Skutterudites, Half Heuslers, Zintls, Mg-Sb Antimonides, Clathrates, FeGa3–type materials, Actinides and Lanthanides, Oxides, Sulfides, Selenides, Silicides, Borides and Carbides. As thermoelectric properties vary with temperature, data are presented at room temperature to enable ready comparison, and also at a higher temperature appropriate to peak performance. An individual table of data and commentary are provided for each family of materials plus source references for all the data.

2022 ◽  
Chenghan Li ◽  
Francesco Paesani ◽  
Gregory A. Voth

It is a common practice in ab initio molecular dynamics (AIMD) simulations of water to use an elevated temperature to overcome the over-structuring and slow diffusion predicted by most current density functional theory (DFT) models. The simulation results obtained in this distinct thermodynamic state are then compared with experimental data at ambient temperature based on the rationale that a higher temperature effectively recovers nuclear quantum effects (NQEs) that are missing in the classical AIMD simulations. In this work, we systematically examine the foundation of this assumption for several DFT models as well as for the many-body MB-pol model. We find for the cases studied that a higher temperature does not correctly mimic NQEs at room temperature, which is especially manifest in significantly different three-molecule correlations as well as hydrogen bond dynamics. In many of these cases, the effects of NQEs are the opposite of the effects of carrying out the simulations at an elevated temperature.

2022 ◽  
Vol 8 ◽  
Peihang Xu ◽  
Christian Furbo Reeder ◽  
Carolin Regina Löscher

Microbial plankton is essential for ocean biogeochemistry. As part of the prokaryotic phototrophic microbial community, both oxygenic phototrophs (OP) and anoxygenic phototrophs (AP) are widely distributed in the ocean and may play a significant role in carbon flow and oxygen production. However, comparative studies of microbial OP and AP have received very little attention, even though their different roles might be important in various marine environments, especially in oxygen minimum zones (OMZ). We explored the spatial distribution of the microbial community in the Baltic Sea, including an OMZ region, with a particular focus on the distribution and activity of OP and AP. We used 16S rRNA amplicon sequencing in combination with a qPCR-based quantification of photosynthesis marker genes. We found that specific bacterial groups dominated surface and intermediate depths, the OMZ, and deep waters, respectively. Salinity, temperature, oxygen, and depth were significant factors explaining the microbial community composition and distribution. A high diversity of OP and AP was observed, including OP-Chlorophyta, Diatoms, Cyanobacteria and Cryptomonads, and AP-Proteobacteria and Chloroflexota. OP were more abundant at most stations compared to AP. OP showed high photosynthetic activity and more photosynthesis activity in higher temperature and upper waters, while AP photosynthesis cannot be detected in most stations. Both, cyanobacterial and eukaryotic OP preferred to live in higher temperature and upper waters, but Cyanobacteria also preferred to live in oxic water while the whole OP community showed preference to live in higher salinity area. However, AP did not show any significant hydrochemical preference but prefer to live with OP community. The Baltic Sea is exposed to multiple climate change related stressors, such as warming, decreasing salinity, and deoxygenation. This study contributes to understanding and interpretation of how microbial community, especially phototrophic groups, might shift in their distribution and activity in a changing ocean like the Baltic Sea.

Yuki Homma

Abstract In plasmas of relatively lower collisionality, such as scrape-off layer (SOL) of fusion tokamak device, parallel heat conductivity of plasma ion becomes smaller than expected by the classical Spitzer-Harm model due to nonlocal kinetic effect. We have assessed, by simulation, impact and role of such kinetic effect of ion heat conductivity (abbreviated by ion KE in this paper) on DEMO relevant tokamak SOL plasma, supposing Japanese demonstration tokamak reactor concept JA DEMO. A series of test simulation, where the ion KE is modeled by a widely used Free-streaming energy (FSE) limited model, has demonstrated the following significant impact of the ion KE on JA DEMO SOL plasma at the baseline operation scenario: (1) the ion KE decreases the ion parallel heat flux density around X-point and further upstream of low field side (LFS) area along the separatrix, where the parallel collisionality tends to decrease due to combination of higher temperature, lower density (i.e. longer mean free path of ion collisions) and higher temperature gradient (shorter characteristic length). Up to 40-60 % of decrease, compared to the case w/o ion KE, is observed among the tested cases where the ion KE level, specified by parameter αi in the FSE-limited model, is scanned over the possible range 0.2 < αi < 2.0. (2) The ion KE leads to significant increase in the ion temperature Ti (up to 600 % of increase among the tested cases) and significant decrease in the ion density ni (up to -80 % of decrease among the tested cases), widely over SOL upstream. By energy balance analysis, it has been suggested that the ion KE affects the upstream ni and Ti, respectively by power of 0.4 and -0.4 of the flux limiting factor, around the separatrix upstream as far as spatial change in plasma parameters are moderate. The results of this study serve as a fundamental assessment of the ion KE for DEMO relevant SOL plasma, clarifying the need of further sophistication of the modeling toward quantitaive prediction.

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