Particulate contaminant removal from spacecraft optical fields of view

1992 ◽  
Author(s):  
Arthur T. Chen
Keyword(s):  
Contaminant Removal ◽  
Optical Fields ◽  
Particulate Contaminant

A novel approach in numerical simulation of contaminant removal by air sparging

2007 ◽  
Vol 7 (3) ◽  
pp. 163-170
Author(s):  
N. Jacimovic ◽  
T. Hosoda ◽  
M. Ivetic ◽  
K. Kishida
Keyword(s):  
Mass Transfer ◽  
Deterministic Model ◽  
Water Phase ◽  
Air Sparging ◽  
Order Kinetic ◽  
Contaminant Removal ◽  
Water Compartments ◽  
Novel Approach ◽  
Adopted Model ◽  
Air Channels

The paper presents a mechanistic/deterministic model for simulation of mass removal during air sparging. From the point of numerical modeling, there are two issues considering air sparging: modeling of air flow and distribution and modeling of mass transport and transfer. Several processes, which are commonly neglected, such as air channeling and pollutant advection by the water phase, are taken into account. The numerical model presented in this paper considers all relevant for mass transfer during the air sparging. Model includes hydrodynamics of air and water phase; calculated air volume content is divided into a number of air channels surrounded by the water phase, which is divided into two compartments. First compartment is immobile and it is in contact with air phase, while the second compartment is mobile. This “mobile-immobile” formulation is a common approach for description of solute transport by groundwater. Mass transfer between two water compartments is modeled as a first order kinetic, where the mass transfer coefficient, representing diffusion and advection in the water phase towards the air channels, is parameter needed to be calibrated. Sorption for both water compartments is considered. The adopted model of contaminant evaporation at the air-water interface is verified by comparison with experimental results available from published sources. Model is used for simulation of two-dimensional air sparging laboratory experiment. Good overall agreement is observed. It is showed that the efficiency of air sparging can be influenced by natural groundwater flow.

scholarly journals Time Decay for Nonlinear Dissipative Schrödinger Equations in Optical Fields

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Nakao Hayashi ◽  
Chunhua Li ◽  
Pavel I. Naumkin
Keyword(s):  
Lower Bound ◽  
Positive Root ◽  
Schrodinger Equations ◽  
Schrödinger Equations ◽  
Time Decay ◽  
Large Initial Data ◽  
Initial Value ◽  
Optical Fields ◽  
Gauge Invariant ◽  
Dissipative Condition

We consider the initial value problem for the nonlinear dissipative Schrödinger equations with a gauge invariant nonlinearityλup-1uof orderpn<p≤1+2/nfor arbitrarily large initial data, where the lower boundpnis a positive root ofn+2p2-6p-n=0forn≥2andp1=1+2forn=1.Our purpose is to extend the previous results for higher space dimensions concerningL2-time decay and to improve the lower bound ofpunder the same dissipative condition onλ∈C:Im⁡ λ<0andIm⁡ λ>p-1/2pRe λas in the previous works.

Single Molecules in Strong Optical Fields: A Variable-Temperature Molecular Junction Spectroscopy Setup

2021 ◽  
Author(s):  
Hai Bi ◽  
Chao Jing ◽  
Peter Hasch ◽  
Yuxiang Gong ◽  
Daniel Gerster ◽  
...  
Keyword(s):  
Variable Temperature ◽  
Single Molecules ◽  
Molecular Junction ◽  
Optical Fields

scholarly journals Microwave oscillator and frequency comb in a silicon optomechanical cavity with a full phononic bandgap

Nanophotonics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 3535-3544 ◽  
Author(s):  
Laura Mercadé ◽  
Leopoldo L. Martín ◽  
Amadeu Griol ◽  
Daniel Navarro-Urrios ◽  
Alejandro Martínez
Keyword(s):  
Phase Noise ◽  
Frequency Comb ◽  
Microwave Oscillator ◽  
New Paradigm ◽  
Mechanical Motion ◽  
Optical Fields ◽  
Optical Resonance ◽  
Processing Elements ◽  
Low Weight ◽  
Harmonic Mixing

AbstractCavity optomechanics has recently emerged as a new paradigm enabling the manipulation of mechanical motion via optical fields tightly confined in deformable cavities. When driving an optomechanical (OM) crystal cavity with a laser blue-detuned with respect to the optical resonance, the mechanical motion is amplified, ultimately resulting in phonon lasing at MHz and even GHz frequencies. In this work, we show that a silicon OM crystal cavity performs as an OM microwave oscillator when pumped above the threshold for self-sustained OM oscillations. To this end, we use an OM cavity designed to have a breathing-like mechanical mode at 3.897 GHz in a full phononic bandgap. Our measurements show that the first harmonic of the detected signal displays a phase noise of ≈−100 dBc/Hz at 100 kHz. Stronger blue-detuned driving leads eventually to the formation of an OM frequency comb, whose lines are spaced by the mechanical frequency. We also measure the phase noise for higher-order harmonics and show that, unlike in Brillouin oscillators, the noise is increased as corresponding to classical harmonic mixing. Finally, we present real-time measurements of the comb waveform and show that it can be fitted to a theoretical model recently presented. Our results suggest that silicon OM cavities could be relevant processing elements in microwave photonics and optical RF processing, in particular in disciplines requiring low weight, compactness and fiber interconnection.

scholarly journals Functionalization of Crumb Rubber Surface for the Incorporation into Asphalt Layers of Reduced Stiffness: An Overview of Existing Treatment Approaches

Recycling ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 19
Author(s):  
Christina Makoundou ◽  
Kenth Johansson ◽  
Viveca Wallqvist ◽  
Cesare Sangiorgi
Keyword(s):  
Gamma Ray ◽  
Crumb Rubber ◽  
Contaminant Removal ◽  
Surface Adhesion ◽  
Asphalt Mixes ◽  
Plastic Recycling ◽  
Physical Treatments ◽  
Uv Ozone ◽  
Reactive Properties ◽  
Mineral Aggregates

The substitution of mineral aggregates with crumb rubber (CR) from waste end-of-life tires (ELTs) in the asphalt concretes, has been considered a sustainable paving industry approach. The rubber has been used to construct pavements with proven enhanced resilience and improved durability. However, some issues related to the rubber’s surface adhesion or swelling may arise with these practices and generate complications (binder consumption, temperatures, mixing times). One possible solution to overcome the materials’ compatibility problems is to pre-treat the CR’s surface before its incorporation into the asphalt mixes to allow a surface functionalization that can enhance coverage and cohesion inside the mixes. The physical treatments using radiations-based beam are already exploited in the plastic recycling industries avoiding the use of chemicals in considerable amounts. Such treatments permit the recovering of large quantities of polymer-based materials and the enhancement of interfacial properties. This article provides an overview of existing surface treatments of polymers and especially rubber, including gamma ray, UV-ozone, microwaves, and plasma. Several studies have shown an overall improvement of the rubber surface’s reactive properties due to contaminant removal or roughness enhancement attributed to cross-linking or scission reactions occurring on the rubber’s surface layer. With those properties, the asphalt mixes’ phase stability properties are increased when the pre-treated rubber is incorporated. The treatments would permit to increase the CR quantities, yet reduce the layer stiffness, and improve the durability and the sustainability of future advanced road pavements.

scholarly journals Removal of Aerosolized Contaminants from Working Canines via a Field Wipe-Down Procedure

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 120
Author(s):  
Erin B. Perry ◽  
Dakota R. Discepolo ◽  
Stephen Y. Liang ◽  
Eileen K. Jenkins
Keyword(s):  
Povidone Iodine ◽  
Chlorhexidine Gluconate ◽  
Evidence Based ◽  
Contaminant Removal ◽  
Cross Contamination ◽  
Fourth Quadrant ◽  
Prior Work ◽  
Chemical Contaminants ◽  
Fluorescent Marker ◽  
Labrador Retrievers

Evidence-based canine decontamination protocols are underrepresented in the veterinary literature. Aerosolized microbiological and chemical contaminants can pose a risk in deployment environments highlighting the need for improved canine field decontamination strategies. Prior work has established the efficacy of traditional, water-intensive methods on contaminant removal from the coat of the working canine; however, it is not known if similar reductions can be achieved with simple field expedient methods when resources are limited. The objective of this study was to measure the reduction of aerosolized contamination via a practical “wipe-down” procedure performed on working canine coats contaminated with a fluorescent, non-toxic, water-based aerosol. Disposable, lint-free towels were saturated with one of three treatments: water, 2% chlorhexidine gluconate scrub (CHX), or 7.5% povidone-iodine scrub (PVD). Both CHX and PVD were diluted at a 1:4 ratio. Treatments were randomly assigned to one of three quadrants established across the shoulders and back of commonly utilized working dog breeds (Labrador retrievers, n = 16; German shepherds, n = 16). The fourth quadrant remained unwiped, thus serving as a control. Reduction in fluorescent marker contamination was measured and compared across all quadrants. PVD demonstrated greater marker reduction compared to CHX or water in both breeds (p < 0.0001). Reduction was similar between CHX or water in Labradors (p = 0.86) and shepherds (p = 0.06). Effective wipe-down strategies using common veterinary cleansers should be further investigated and incorporated into decontamination practices to safeguard working canine health and prevent cross-contamination of human personnel working with these animals.

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