scholarly journals Radiative sky cooling: fundamental physics, materials, structures, and applications

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 997-1015 ◽  
Author(s):  
Xingshu Sun ◽  
Yubo Sun ◽  
Zhiguang Zhou ◽  
Muhammad Ashraful Alam ◽  
Peter Bermel
Keyword(s):  
Infrared Detectors ◽  
Detailed Comparison ◽  
Radiative Cooling ◽  
Temperature Sensitive ◽  
Bulk Materials ◽  
Fundamental Physics ◽  
Potential Applications ◽  
Modeling And Experiments ◽  
Ancient Times ◽  
Nanophotonic Structures

AbstractRadiative sky cooling reduces the temperature of a system by promoting heat exchange with the sky; its key advantage is that no input energy is required. We will review the origins of radiative sky cooling from ancient times to the modern day, and illustrate how the fundamental physics of radiative cooling calls for a combination of properties that may not occur in bulk materials. A detailed comparison with recent modeling and experiments on nanophotonic structures will then illustrate the advantages of this recently emerging approach. Potential applications of these radiative cooling materials to a variety of temperature-sensitive optoelectronic devices, such as photovoltaics, thermophotovoltaics, rectennas, and infrared detectors, will then be discussed. This review will conclude by forecasting the prospects for the field as a whole in both terrestrial and space-based systems.

scholarly journals Evaluating the efficiency of utilizing selectively optimized metamaterial nanostructures for passive radiative cooling of satellites and components

2019 ◽  
Vol 6 ◽  
pp. 110-123
Author(s):  
Federico Moreno ◽  
Swapnil Poudyal ◽  
Otto Cranwell ◽  
Ben Andrew
Keyword(s):  
Meta Analysis ◽  
Inductive Reasoning ◽  
Visible Spectrum ◽  
Optical Filters ◽  
Thermal Control ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Temperature Sensitive ◽  
Selective Absorption ◽  
Nanophotonic Structures

The need for efficient, smart radiators and thermal control technologies will be imperative to ensure the longevity of satellites and for carrying out temperature sensitive operations in space. Advancement in nanofabrication techniques has brought about the ability to create metamaterial nanostructures and selectively control their optical properties so that they reflect better in the visible spectrum and strongly emit in the infrared spectrum, which allows for better cooling. This meta-analysis looks at contemporary research that has utilised metamaterial nanostructures for passive radiative cooling attempting to identify the cooling trends among these structures. The absorbance, emissivity and reflection spectra of these structures are compared, and their effectiveness compared to conventional coolant coatings is critiqued upon. The defining thermodynamic parameters for this study were radiative cooling power and temperature reduction. Through inductive reasoning, we predict that the emissivity in the infrared of a pyramidal layered structure of Al2O3, TiO2 and SiO2 can outperform current material choices. Improving efficiency with the prediction outlined can provide increased radiative cooling. Keywords: Passive radiative cooling; thermal radiation; metamaterials; broadband optical filters; selective absorption and emission; two-dimensional thin film coatings; nanophotonic structures

Microcavities

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Quantum Wells ◽  
Strong Light ◽  
Fundamental Physics ◽  
Postgraduate Students ◽  
Optical Cavities ◽  
Semiconductor Quantum Wells ◽  
Exciton Polaritons ◽  
Different Types ◽  
Potential Applications ◽  
Experimental Findings

Both rich fundamental physics of microcavities and their intriguing potential applications are addressed in this book, oriented to undergraduate and postgraduate students as well as to physicists and engineers. We describe the essential steps of development of the physics of microcavities in their chronological order. We show how different types of structures combining optical and electronic confinement have come into play and were used to realize first weak and later strong light–matter coupling regimes. We discuss photonic crystals, microspheres, pillars and other types of artificial optical cavities with embedded semiconductor quantum wells, wires and dots. We present the most striking experimental findings of the recent two decades in the optics of semiconductor quantum structures. We address the fundamental physics and applications of superposition light-matter quasiparticles: exciton-polaritons and describe the most essential phenomena of modern Polaritonics: Physics of the Liquid Light. The book is intended as a working manual for advanced or graduate students and new researchers in the field.

scholarly journals Smart Hydrogel Bilayers Prepared by Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1753
Author(s):  
Weixian Huo ◽  
Heng An ◽  
Shuquan Chang ◽  
Shengsheng Yang ◽  
Yin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gamma Radiation ◽  
Antibacterial Properties ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Temperature Changes ◽  
Smart Hydrogel ◽  
Isopropyl Acrylamide ◽  
Hydrogel Synthesis ◽  
Potential Applications

Environment-responsive hydrogel actuators have attracted tremendous attention due to their intriguing properties. Gamma radiation has been considered as a green cross-linking process for hydrogel synthesis, as toxic cross-linking agents and initiators were not required. In this work, chitosan/agar/P(N-isopropyl acrylamide-co-acrylamide) (CS/agar/P(NIPAM-co-AM)) and CS/agar/Montmorillonite (MMT)/PNIPAM temperature-sensitive hydrogel bilayers were synthesized via gamma radiation at room temperature. The mechanical properties and temperature sensitivity of hydrogels under different agar content and irradiation doses were explored. The enhancement of the mechanical properties of the composite hydrogel can be attributed to the presence of agar and MMT. Due to the different temperature sensitivities provided by the two layers of hydrogel, they can move autonomously and act as a flexible gripper as the temperature changes. Thanks to the antibacterial properties of the hydrogel, their storage time and service life may be improved. The as prepared hydrogel bilayers have potential applications in control devices, soft robots, artificial muscles and other fields.

Structure and Electrical Properties of an Assembly of Au Nanoclusters

2001 ◽  
Vol 635 ◽  
Author(s):  
G. Muralidharan ◽  
L. Maya ◽  
T. Thundat
Keyword(s):  
Threshold Voltage ◽  
Specific Reference ◽  
Low Molecular Weight ◽  
Electrical Measurements ◽  
Monolayer Films ◽  
Au Nanoclusters ◽  
Fundamental Physics ◽  
Au Clusters ◽  
Significant Interest ◽  
Potential Applications

AbstractConduction through an assembly of nanosized clusters coupled by tunneling barriers is of significant interest both for understanding the fundamental physics involved and for potential applications. In this study, we describe a technique for preparing relatively large (dimensions of a few 100 µm to a few mm in size) monolayer films consisting of 3 nm diameter Au clusters coated with mercaptododecanoic acid, using low molecular weight-polymers as coupling agents. Electrical measurements of the assembly show non-linear characteristics. Below a certain threshold voltage, the current does not vary with an increase in voltage. Above this threshold voltage, current increases with voltage and can be described by a power-law relationship with an exponent close to unity. These characteristics of the I-V curve are discussed with specific reference to theoretical studies on conduction through an array of capacitance-coupled metallic islands and previous experimental results in similar systems.

scholarly journals Field-induced double spin spiral in a frustrated chiral magnet

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Mahesh Ramakrishnan ◽  
Evan Constable ◽  
Andres Cano ◽  
Maxim Mostovoy ◽  
Jonathan S. White ◽  
...  
Keyword(s):  
Topological Defects ◽  
Electric Polarization ◽  
Fundamental Physics ◽  
Magnetic Systems ◽  
Long Wavelength ◽  
Double Spin ◽  
Potential Applications ◽  
Magnetic Skyrmions ◽  
Topological Correlations ◽  
Spin Spiral

AbstractMagnetic ground states with peculiar spin textures, such as magnetic skyrmions and multifunctional domains are of enormous interest for the fundamental physics governing their origin as well as potential applications in emerging technologies. Of particular interest are multiferroics, where sophisticated interactions between electric and magnetic phenomena can be used to tailor several functionalities. We report the direct observation of a magnetic field induced long-wavelength spin spiral modulation in the chiral compound Ba$${}_{3}$$3TaFe$${}_{3}$$3Si$${}_{2}$$2O$${}_{14}$$14, which emerges out of a helical ground state, and is hallmarked by the onset of a unique chirality-dependent contribution to the bulk electric polarization. The periodicity of the field-induced modulation, several hundreds of nm depending on the field value, is comparable to the length scales of mesoscopic topological defects such as skyrmions, merons, and solitons. The phase transition and observed threshold behavior are consistent with a phenomenology based on the allowed Lifshitz invariants for the chiral symmetry of langasite, which intriguingly contain all the essential ingredients for the realization of topologically stable antiferromagnetic skyrmions. Our findings open up new directions to explore topological correlations of antiferromagnetic spintronic systems based on non-collinear magnetic systems with additional ferroic functionalities.

scholarly journals An emerging Janus MoSeTe material for potential applications in optoelectronic devices

2019 ◽  
Vol 7 (39) ◽  
pp. 12312-12320 ◽  
Author(s):  
Xiaoyong Yang ◽  
Deobrat Singh ◽  
Zhitong Xu ◽  
Ziwei Wang ◽  
Rajeev Ahuja
Keyword(s):  
First Principles ◽  
Transition Metal Dichalcogenides ◽  
Chemical Properties ◽  
Detailed Comparison ◽  
Physical And Chemical Properties ◽  
First Principles Calculations ◽  
Potential Applications ◽  
Metal Dichalcogenides ◽  
Physical And Chemical ◽  
And Chemical Properties

Motivated by the extraordinary physical and chemical properties of Janus transition-metal dichalcogenides (TMDs) due to the change of the crystal field originating from their asymmetry structures, the electronic and optical properties of the MoSeTe monolayer in 2H and 1T phases are systematically studied by first-principles calculations, and a detailed comparison with the parental MoSe2 and MoTe2 monolayer is made.

scholarly journals Self-Assembly of Temperature Sensitive Unilamellar Vesicles by a Blend of Block Copolymers in Aqueous Solution

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 63 ◽  
Author(s):  
Jong Dae Jang ◽  
Changwoo Do ◽  
Joona Bang ◽  
Young Soo Han ◽  
Tae-Hwan Kim
Keyword(s):  
Block Copolymers ◽  
Hydrophobic Interaction ◽  
Self Assembly ◽  
Small Angle Neutron Scattering ◽  
Mass Fraction ◽  
Temperature Sensitive ◽  
Vesicular Structure ◽  
Wide Range ◽  
Scattering Measurements ◽  
Potential Applications

A self-assembled unilamellar vesicle, which can be used as a drug delivery system, was easily and simply fabricated using a blended system of Pluronic block copolymers. Controlling the hydrophilic mass fraction of block copolymers (by blending the block copolymer with a different hydrophilic mass fraction) and temperature (i.e., the hydrophobic interaction is controlled), a vesicular structure was formed. Small angle neutron scattering measurements showed that the vesicular structure had diameters of empty cores from 13.6 nm to 79.6 nm, and thicknesses of the bilayers from 2.2 nm to 8.7 nm when the hydrophobic interaction was changed. Therefore, considering that the temperature of the vesicle formation is controllable by the concentration of the blended block copolymers, it is possible for them to be applied in a wide range of potential applications, for example, as nanoreactors and nanovehicles.

scholarly journals Advances in Nanomaterials Sciences and Nanotechnology for Sustainable Development: A Review

2021 ◽  
Vol 47 (4) ◽  
pp. 1450-1463
Author(s):  
Gervas E. Assey ◽  
Wilhelm S. Malasi
Keyword(s):  
Sustainable Development ◽  
Environmental Remediation ◽  
Inorganic Materials ◽  
Co2 Mitigation ◽  
Bulk Materials ◽  
Agriculture Industry ◽  
Potential Applications ◽  
Pharmaceutical Industries ◽  
Optical And Magnetic Properties ◽  
External Dimension

The fields of materials sciences have great opportunities to address the challenges of sustainable development of modern societies. The sub-disciplines of materials sciences of interest in this review are nanomaterials sciences and nanotechnology. Nanomaterials possess one external dimension measuring 1-100 nm. They have larger surface area for the same mass than their bulk materials. They are more reactive with effects on their electrical, optical and magnetic properties. Thus, nanomaterials are promising for sustainable development in the areas of energy, water, chemicals, electronics, medical and pharmaceutical industries, CO2 mitigation and agriculture. To this end, this review explores the advances in nanomaterials sciences, nanotechnology and the potential applications of nanomaterials for sustainable development. In this review, 73 peer reviewed articles and abstracts were retrieved. The review considered nanomaterials of carbon, inorganic materials, semiconductors, polymeric and lipid based materials. It has been found that nanomaterials sciences and nanotechnology is promising for potential applications in the areas of environmental remediation, energy, food, agriculture, industry, molecular biology, medicine and in pharmaceutical industries for sustainable development. Keywords: nanomaterials sciences, nanotechnology, sustainable development

scholarly journals A general model of conversational dynamics and an example application in serious illness communication

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253124
Author(s):  
Laurence A. Clarfeld ◽  
Robert Gramling ◽  
Donna M. Rizzo ◽  
Margaret J. Eppstein
Keyword(s):  
Information Flow ◽  
Markov Models ◽  
Serious Illness ◽  
Sequential Dependencies ◽  
Novel Approach ◽  
Potential Applications ◽  
Primary Means ◽  
Ancient Times ◽  
Patient Values ◽  
Seriously Ill Patients

Conversation has been a primary means for the exchange of information since ancient times. Understanding patterns of information flow in conversations is a critical step in assessing and improving communication quality. In this paper, we describe COnversational DYnamics Model (CODYM) analysis, a novel approach for studying patterns of information flow in conversations. CODYMs are Markov Models that capture sequential dependencies in the lengths of speaker turns. The proposed method is automated and scalable, and preserves the privacy of the conversational participants. The primary function of CODYM analysis is to quantify and visualize patterns of information flow, concisely summarized over sequential turns from one or more conversations. Our approach is general and complements existing methods, providing a new tool for use in the analysis of any type of conversation. As an important first application, we demonstrate the model on transcribed conversations between palliative care clinicians and seriously ill patients. These conversations are dynamic and complex, taking place amidst heavy emotions, and include difficult topics such as end-of-life preferences and patient values. We use CODYMs to identify normative patterns of information flow in serious illness conversations, show how these normative patterns change over the course of the conversations, and show how they differ in conversations where the patient does or doesn’t audibly express anger or fear. Potential applications of CODYMs range from assessment and training of effective healthcare communication to comparing conversational dynamics across languages, cultures, and contexts with the prospect of identifying universal similarities and unique “fingerprints” of information flow.

Incommensurate Structures in Rhenium Disilicide

1998 ◽  
Vol 4 (S2) ◽  
pp. 534-535
Author(s):  
A. Misra ◽  
F. Chu ◽  
T.E. Mitchell
Keyword(s):  
Infrared Detectors ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
Orthorhombic Distortion ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications ◽  
Monoclinic Distortion ◽  
Incommensurate Structures ◽  
High Temperature Structural Material

The binary ReSi2 and ternary (Mo,Re)Si2 alloys are of interest due to potential applications as infrared detectors [1]. Also, Re may be a beneficial alloying element to MoSi2 which is a potential high temperature structural material [2]. A recent study of the structure of ReSi2 by X-ray diffraction (XRD) revealed an orthorhombic distortion (a= 0.3121 nm, b= 0.3139 nm and c= 0.7670 nm) from the tetragonal CI lb MoSi2 structure and a Si-deficient composition of Re4Si7 [3]. Further, a weak monoclinic distortion (β=89.87°) was also inferred from high-resolution XRD [3]. In the present investigation, the orthorhombic distortion and the Si-deficient stoichiometry were confirmed by XRD and the structure of arc-melted Re4Si7 studied by transmission electron microscopy (TEM).A bright field (BF) TEM image and the corresponding [010] zone axis selected area diffraction pattern (SADP) are shown in Fig. 1. In addition to the fundamental reflections for tetragonal Cllb MoSi2 structure,

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