scholarly journals Metalized polyamide heterostructure as a moisture-responsive actuator for multimodal adaptive personal heat management

2021 ◽  
Vol 7 (51) ◽  
Author(s):  
Xiuqiang Li ◽  
Boran Ma ◽  
Jingyuan Dai ◽  
Chenxi Sui ◽  
Divya Pande ◽  
...  
Keyword(s):  
Heat Management

Influence of Metal Substitution on the Pressure-Induced Phase Change in Flexible Zeolitic Imidazolate Frameworks

2018 ◽  
Author(s):  
C. Michael McGuirk ◽  
Tomče Runčevski ◽  
Julia Oktawiec ◽  
Ari Turkiewicz ◽  
mercedes K. taylor ◽  
...  
Keyword(s):  
Phase Change ◽  
Single Crystal ◽  
Gas Adsorption ◽  
High Capacity ◽  
Phase Changes ◽  
Zeolitic Imidazolate Frameworks ◽  
Metal Substitution ◽  
Heat Management ◽  
Metal Organic ◽  
First Time

<p>Metal–organic frameworks that display step-shaped adsorption profiles arising from discrete pressure-induced phase changes are promising materials for applications in both high-capacity gas storage and energy-efficient gas separations. The thorough investigation of such materials through chemical diversification, gas adsorption measurements, and <i>in situ </i>structural characterization is therefore crucial for broadening their utility. We examine a series of isoreticular, flexible zeolitic imidazolate frameworks (ZIFs) of the type M(bim)<sub>2</sub> (SOD; M = Zn<sup> </sup>(ZIF-7), Co (ZIF-9), Cd (CdIF-13); bim<sup>–</sup> = benzimidazolate), and elucidate the effects of metal substitution on the pressure-responsive phase changes and the resulting CO<sub>2</sub> and CH<sub>4</sub> step positions, pre-step uptakes, and step capacities. Using ZIF-7 as a benchmark, we reexamine the poorly understood structural transition responsible for its adsorption steps and, through high-pressure adsorption measurements, verify that it displays a step in its CH<sub>4 </sub>adsorption isotherms. The ZIF-9 material is shown to undergo an analogous phase change, yielding adsorption steps for CO<sub>2</sub> and CH<sub>4</sub> with similar profiles and capacities to ZIF-7, but with shifted threshold pressures. Further, the Cd<sup>2+</sup> analogue CdIF-13 is reported here for the first time, and shown to display adsorption behavior distinct from both ZIF-7 and ZIF-9, with negligible pre-step adsorption, a ~50% increase in CO<sub>2</sub> and CH<sub>4</sub> capacity, and dramatically higher threshold adsorption pressures. Remarkably, a single-crystal-to-single-crystal phase change to a pore-gated phase is also achieved with CdIF-13, providing insight into the phase change that yields step-shaped adsorption in these flexible ZIFs. Finally, we show that the endothermic phase change of these frameworks provides intrinsic heat management during gas adsorption. </p>

A Triple-Mode Midinfrared Modulator for Radiative Heat Management of Objects with Various Emissivity

Nano Letters ◽  
2021 ◽  
Author(s):  
Haoming Fang ◽  
Wanrong Xie ◽  
Xiuqiang Li ◽  
Kebin Fan ◽  
Yi-Ting Lai ◽  
...  
Keyword(s):  
Radiative Heat ◽  
Heat Management ◽  
Triple Mode

scholarly journals Anomalous thermal conductivity enhancement in low dimensional resonant nanostructures due to imperfections

Nanoscale ◽  
2021 ◽  
Author(s):  
Hongying Wang ◽  
Yajuan Cheng ◽  
Zheyong Fan ◽  
Yangyu Guo ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Conversion ◽  
Thermal Conductivity Enhancement ◽  
Heat Management ◽  
Thermoelectric Energy Conversion ◽  
Conductivity Enhancement ◽  
Thermoelectric Energy ◽  
Low Dimensional

Nanophononic metamaterials have broad applications in fields such as heat management, thermoelectric energy conversion, and nanoelectronics. Phonon resonance in pillared low-dimensional structures has been suggested to be a feasible approach...

scholarly journals Giant Magnetoresistance and Magneto-Thermopower in 3D Interconnected NixFe1−x/Cu Multilayered Nanowire Networks

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1133
Author(s):  
Nicolas Marchal ◽  
Tristan da Câmara Santa Clara Gomes ◽  
Flavio Abreu Araujo ◽  
Luc Piraux
Keyword(s):  
Giant Magnetoresistance ◽  
Nanowire Array ◽  
Three Dimensional ◽  
Strong Increase ◽  
Thermoelectric Effect ◽  
Heat Management ◽  
Thermoelectric Effects ◽  
Nanowire Network ◽  
Potential Applications ◽  
Nanowire Networks

The versatility of the template-assisted electrodeposition technique to fabricate complex three-dimensional networks made of interconnected nanowires allows one to easily stack ferromagnetic and non-magnetic metallic layers along the nanowire axis. This leads to the fabrication of unique multilayered nanowire network films showing giant magnetoresistance effect in the current-perpendicular-to-plane configuration that can be reliably measured along the macroscopic in-plane direction of the films. Moreover, the system also enables reliable measurements of the analogous magneto-thermoelectric properties of the multilayered nanowire networks. Here, three-dimensional interconnected NixFe1−x/Cu multilayered nanowire networks (with 0.60≤x≤0.97) are fabricated and characterized, leading to large magnetoresistance and magneto-thermopower ratios up to 17% and −25% in Ni80Fe20/Cu, respectively. A strong contrast is observed between the amplitudes of magnetoresistance and magneto-thermoelectric effects depending on the Ni content of the NiFe alloys. In particular, for the highest Ni concentrations, a strong increase in the magneto-thermoelectric effect is observed, more than a factor of 7 larger than the magnetoresistive effect for Ni97Fe3/Cu multilayers. This sharp increase is mainly due to an increase in the spin-dependent Seebeck coefficient from −7 µV/K for the Ni60Fe40/Cu and Ni70Fe30/Cu nanowire arrays to −21 µV/K for the Ni97Fe3/Cu nanowire array. The enhancement of the magneto-thermoelectric effect for multilayered nanowire networks based on dilute Ni alloys is promising for obtaining a flexible magnetic switch for thermoelectric generation for potential applications in heat management or logic devices using thermal energy.

Solar Heat Underground Storage Based Air Conditioning Vis-à-Vis Conventional HVAC Experimental Validation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Carlos R. de Nardin ◽  
Felipe T. Fernandes ◽  
Adriano J. Longo ◽  
Luciano P. Lima ◽  
Felix A. Farret ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Heat Pumps ◽  
Conventional Heating ◽  
Management Technique ◽  
Air Conditioner ◽  
Heat Management ◽  
Air Conditioners ◽  
Solar Heat ◽  
Reduction Of Energy Consumption ◽  
The One

This paper presents a comparison of air conditioners using the conventional heating, ventilation, and air conditioning heat pumps and the one using solar heat stored underground, also known as shallow geothermal air conditioning. The proposed air conditioner with solar heat stored underground reunites practical data from an implementation of the heuristic perturb-and-observe (P&O) control and a heat management technique. The aim is to find out the best possible heat exchange between the room ambient and the underground soil heat to reduce its overall consumption without any heat pump. Comparative tests were conducted in two similar rooms, each one equipped with one of the two types of air conditioning. The room temperature with the conventional air conditioning was maintained as close as possible to the temperature of the test room with shallow geothermal conditioning to allow an acceptable data validation. The experiments made both in the winter of 2014 and in the summer of 2015 in Santa Maria, South Brazil, demonstrated that the conventional air conditioner consumed 19.08 kWh and the shallow geothermal conditioner (SGC) consumed only 4.65 kWh, therefore, representing a reduction of energy consumption of approximately 75%.

Ultra-Wideband Transparent Conductive Electrode for Electrochromic Synergistic Solar and Radiative Heat Management

2021 ◽  
pp. 3906-3915
Author(s):  
Yunfei Rao ◽  
Jingyuan Dai ◽  
Chenxi Sui ◽  
Yi-Ting Lai ◽  
Zhe Li ◽  
...  
Keyword(s):  
Radiative Heat ◽  
Ultra Wideband ◽  
Heat Management ◽  
Transparent Conductive Electrode

scholarly journals Beyond Threshold Approaches to Extreme Heat: Repositioning Adaptation as Everyday Practice

2018 ◽  
Vol 10 (4) ◽  
pp. 885-898 ◽  
Author(s):  
Elspeth Oppermann ◽  
Yolande Strengers ◽  
Cecily Maller ◽  
Lauren Rickards ◽  
Matt Brearley
Keyword(s):  
Social Practice ◽  
Climate Adaptation ◽  
Extreme Heat ◽  
Extreme Conditions ◽  
Work Intensity ◽  
Heat Management ◽  
Everyday Practices ◽  
Starting Point ◽  
Climatic Impacts ◽  
External Risk

Abstract One of climate change’s most certain impacts is increasingly frequent and extreme heat. Heat management and climate adaptation policies generally utilize temperature and humidity thresholds to identify what constitute “extreme” conditions. In the workplace, such thresholds can be used to trigger reductions in work intensity and/or duration. In regions that routinely exceed proposed thresholds, however, this approach can be deeply problematic and raises critical questions about how frequently exposed populations already manage and mitigate the effects of extreme heat. Drawing on social practice theories, this paper repositions everyday engagements with extreme heat in terms of practices of work. It finds that bodies absorb and produce heat through practices, challenging the view that extreme heat is an “external” risk to which bodies are “exposed”. This theoretical starting point also challenges the utility of threshold-based adaptation strategies by demonstrating how heat is actively coproduced by living, performing bodies in weather. This argument is exemplified through a case study of outdoor, manual workers in Australia’s monsoon tropics, where work practices were adapted to reduce thermal load. More specifically, we find that workers “weather” work and “work” the weather to enable work to be done in extreme conditions. Our analysis of everyday heat adaptation draws attention to the generative capacities of bodies and unsettles two established separations: 1) that between climatic exposure and sensitivity, calling for a more embodied, experiential, and performed perspective and 2) that between climatic impacts and (mal)adaptation, calling for an understanding of climate adaptation, as located in everyday practices, in the management of bodies in weather.

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