Добірка наукової літератури з теми "Partial transfer absorption imaging"

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Статті в журналах з теми "Partial transfer absorption imaging"

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Seroka, Erin Marshall, Ana Valdés Curiel, Dimitrios Trypogeorgos, Nathan Lundblad, and Ian B. Spielman. "Repeated measurements with minimally destructive partial-transfer absorption imaging." Optics Express 27, no. 25 (December 2, 2019): 36611. http://dx.doi.org/10.1364/oe.27.036611.

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Ramanathan, Anand, Sérgio R. Muniz, Kevin C. Wright, Russell P. Anderson, William D. Phillips, Kristian Helmerson, and Gretchen K. Campbell. "Partial-transfer absorption imaging: A versatile technique for optimal imaging of ultracold gases." Review of Scientific Instruments 83, no. 8 (August 2012): 083119. http://dx.doi.org/10.1063/1.4747163.

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Park, Changyong, and Paul A. Fenter. "Phasing of resonant anomalous X-ray reflectivity spectra and direct Fourier synthesis of element-specific partial structures at buried interfaces." Journal of Applied Crystallography 40, no. 2 (March 12, 2007): 290–301. http://dx.doi.org/10.1107/s0021889806053131.

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A formalism for model-independent determination of element-specific partial structures at buried interfaces using the phase-dependent behavior of resonant anomalous X-ray reflectivity (RAXR) data is described. Each RAXR spectrum (i.e.reflectivityversusenergy at a fixed momentum transfer near the absorption edge of interest) is uniquely constrained by the amplitude and phase of the resonant partial structure factor with pre-determined non-resonant total structure factor and anomalous dispersion corrections of the resonant species. The element-specific partial density distribution is then imaged by discrete Fourier synthesis with the partial structure factor. The utility of this approach is demonstrated in the comparison of Rb+and Sr2+distributions at muscovite (001)–aqueous solution interfaces derived by model-independent and model-dependent approaches. This imaging method is useful for rapid determination of complex buried interfacial structures where element-specific atomic distributions are poorly constrained by conventional X-ray reflectivity analysis.
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Li, Liushuang, Ye Yuan, Jiawen Wu, Baohua Zhu, and Yuzong Gu. "The Third-Order Nonlinear Optical Properties of Sb2S3/RGO Nanocomposites." Photonics 9, no. 4 (March 23, 2022): 213. http://dx.doi.org/10.3390/photonics9040213.

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Antimony sulfide/reduced graphene oxide (Sb2S3/RGO) nanocomposites were synthesized via a facile, one-step solvothermal method. XRD, SEM, FTIR, and Raman spectroscopy were used to characterize the uniform distribution of Sb2S3 nanoparticles on the surface of graphene through partial chemical bonds. The third-order nonlinear optical (NLO) properties of Sb2S3, RGO, and Sb2S3/RGO samples were investigated by using the Z-scan technique under Nd:YAG picosecond pulsed laser at 532 nm. The results showed that pure Sb2S3 particles exhibited two-photon absorption (TPA), while the Sb2S3/RGO composites switched to variable saturated absorption (SA) properties due to the addition of different concentrations of graphene. Moreover, the third-order nonlinear susceptibilities of the composites were also tunable with the concentration of the graphene. The third-order nonlinear susceptibility of the Sb2S3/RGO sample can achieve 8.63 × 10−12 esu. The mechanism for these properties can be attributed to the change of the band gap and the formation of chemical bonds supplying channels for photo-induced charge transfer between Sb2S3 nanoparticles and the graphene. These tunable NLO properties of Sb2S3/RGO composites can be applicable to photonic devices such as Q-switches, mode-locking devices, and optical switches.
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Castañeda, Román. "Spatially partial coherence transfer and imaging." Journal of Modern Optics 46, no. 11 (September 1999): 1605–10. http://dx.doi.org/10.1080/09500349908231359.

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Castaneda, Roman. "Spatially partial coherence transfer and imaging." Journal of Modern Optics 46, no. 11 (September 15, 1999): 1605–10. http://dx.doi.org/10.1080/095003499148864.

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Pongayi Ponnusamy Selvi and Rajoo Baskar, Pongayi Ponnusamy Selvi and Rajoo Baskar. "Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column." Journal of the chemical society of pakistan 41, no. 5 (2019): 820. http://dx.doi.org/10.52568/000803/jcsp/41.05.2019.

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The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.
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Norton, Valerie A., and Daniel P. Weitekamp. "Communication: Partial polarization transfer for single-scan spectroscopy and imaging." Journal of Chemical Physics 135, no. 14 (October 14, 2011): 141107. http://dx.doi.org/10.1063/1.3652965.

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Tang, Chun Li, and Qian Wang. "The Pressure Differential Analysis of LiCl Solution Absorption Process." Advanced Materials Research 732-733 (August 2013): 541–47. http://dx.doi.org/10.4028/www.scientific.net/amr.732-733.541.

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To improve indoor air quality, mass transfer is an important part in air handling process, which is helpful for the control of humidity of air. This paper presents mass transfer dynamic analysis of isothermal and opposite flow process theoretically. The pressure difference analysis is used to show the changing of pressures of two phases in dehumidification process. It calculates the partial pressure of water vapor in wet air and the vapor pressure of LiCl solution. Also it gives the curves of pressure change in dehumidification of isothermal and opposite flow by lithium chloride. Results from this paper can be used as theoretical foundation for the experimental design of dehumidification of air by LiCl solution.
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Sufyan, Abu, Yani Rohmayani, Tubagus Chaeru Nugraha, and Mohammed H. Al-Khresheh. "INTERFERENCE IN THE DEVELOPMENT OF ARABIC VOCABULARY (A MORPHOLOGICAL REVIEW)." Humanities & Social Sciences Reviews 8, no. 4 (September 26, 2020): 1319–29. http://dx.doi.org/10.18510/hssr.2020.84124.

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Purpose: This study aims to describe the forms of Arabic language interference on terminologies in the domains of science, technology, and art. Methodology: The study was conducted morphophonologically using descriptive-analytical research methods. The descriptive-analytic research method was used to facilitate the achievement of goals specified in this study. The data findings were reviewed using the distributional method. Main Findings: The study found that language interference is an aspect of vocabulary development and enrichment, which requires harmonization of speech sounds. The results showed that in the Arabic language, interference produced partial absorption and full absorption. Phonologically, partial absorption occurred through the absorption of sound elements at the beginning or end of a word. Applications: Understanding the issue of language transfer in the development of Arabic vocabulary is useful for non- native Arabic speakers. The findings can also help Arabic teachers revise their teachings methods accordingly. Novelty/Originality of this study: This study contributed to a better understanding of the forms of phonological interference of foreign languages into the Arabic language. These forms can be represented as partial absorption, total absorption, and sound change. While in morphological forms, interference causes different developments of word patterns from classical Arabic.
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Дисертації з теми "Partial transfer absorption imaging"

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Samsodien, Mogammad Luqmaan. "Nanoparticles for use in imaging, catalysis and phthalocyanine synthesis." University of the Western Cape, 2018. http://hdl.handle.net/11394/6446.

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Magister Scientiae - MSc (Chemistry)
Nanoscience and nanotechnology are known to be interdisciplinary, crossing and combining various fields and disciplines in pursuit of desirable outcomes. This has brought about applications of nanoscience and nanotechnology in multitudes of industries, spanning from the health, pharmaceutical to industrial industry. Within the health industry, the medical field has seen much advancement through nanoscience and nanotechnology. The importance of finding cures to diseases is top priorities within the medical field, along with advancements in understanding and diagnosing diseases. Due to these outcomes, we see the emergence of imaging techniques playing a crucial role. The work covered in this thesis looks at a prospective luminescent agent applicable in the medical field for bio-imaging, but also at a possible phthalocyanine sensitizer for treatment of cancer through photodynamic therapy. Another area where nanoscience and nanotechnology are found is in industry, where nanoparticles are utilised as catalysts in many synthetic reactions. Highly desirable catalysts in industry are those involved in oxidative reactions where we explore a metal nanoparticle catalyst within this work.
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Wolswijk, Louise. "Equilibrium and out-of-equilibrium physics of Bose gases at finite temperature." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/347823.

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The physics of ultracold quantum gases has been the subject of a long-lasting and intense research activity, which started almost a century ago with purely theoretical studies and had a fluorishing experimental development after the implementation of laser and evaporative cooling techniques that led to the first realization of a Bose Einstein condensate (BEC) over 25 years ago. In recent years, a great interest in ultracold atoms has developed for their use as platforms for quantum technologies, given the high degree of control and tunability offered by ultracold atom systems. These features make ultracold atoms an ideal test bench for simulating and studying experimentally, in a controlled environment, physical phenomena analogous to those occurring in other, more complicated, or even inaccessible systems, which is the idea at the heart of quantum simulation. In the rapidly developing field of quantum technologies, it is highly important to acquire an in-depth understanding of the state of the quantum many-body system that is used, and of the processes needed to reach the desired state. The preparation of the system in a given target state often involves the crossing of second order phase transitions, bringing the system strongly out-of-equilibrium. A better understanding of the out-of-equilibrium processes occurring in the vicinity of the transition, and of the relaxation dynamics towards the final equilibrium condition, is crucial in order to produce well-controlled quantum states in an efficient way. In this thesis I present the results of the research activity that I performed during my PhD at the BEC1 laboratory of the BEC center, working on ultracold gases of 23Na atoms in an elongated harmonic trap. This work had two main goals: the accurate determination of the equilibrium properties of a Bose gas at finite temperature, by the measurement of its equation of state, and the investigation of the out-of-equilibrium dynamics occurring when a Bose Einstein condensate is prepared by cooling a thermal cloud at a finite rate across the BEC phase transition.To study the equilibrium physics of a trapped atomic cloud, it is crucial to be able to observe its density distribution in situ. This requires a high optical resolution to accurately obtain the density profile of the atomic distribution, from which thermodynamic quantities can then be extracted. In particular, in a partially condensed atomic cloud at finite temperature, it is challenging to resolve well also the boundaries of the BEC, where the condensate fraction rapidly drops in a narrow spatial region. This required an upgrade of the experimental apparatus in order to obtain a high enough resolution. I designed, tested and implemented in the experimental setup new imaging systems for all main directions of view. Particular attention was paid for the vertical imaging system, which was designed to image the condensates in trap with a resolution below 2 μm, with about a factor 4 improvement compared to the previous setup. The implementation of the new imaging systems involved a partial rebuilding of the experimental apparatus used for cooling the atoms. This created the occasion for an optimization of the whole system to obtain more stable working conditions. Concurrently I also realized and included in the experiment an optical setup for the use of a Digital Micromirror Device (DMD) to project time-dependent arbitrary light patterns on the atoms, creating optical potentials that can be controlled at will. The use of this device opens up exciting future scenarios where it will be possible to locally modify the trapping potential and to create well-controlled barriers moving through the atomic cloud. Another challenge in imaging the density distribution in situ is determined by the fact that the maximum optical density (OD) of the BEC, in the trap center, exceeds the low OD of the thermal tails by several orders of magnitude. In order to obtain an accurate image of the whole density profile, we developed a minimally destructive, multi-shot imaging technique, based on the partial transfer of a fraction of atoms to an auxiliary state, which is then probed. Taking multiple images at different extraction fractions, we are able to reconstruct the whole density profile of the atomic cloud avoiding saturation and maintaining a good signal to noise ratio. This technique, together with the improvements in the imaging resolution, has allowed us to accurately obtain the optical density profile of the Bose gas in trap, from which the 3D density profile was then calculated applying an inverse Abel transform, taking advantage of the symmetry of the trap. From images of the same cloud after a time-of-flight expansion, we measured the temperature of the gas. From these quantities we could find the pressure as a function of the density and temperature, determining the canonical equation of state of the weakly interacting Bose gas in equilibrium at finite temperature. These measurements also allowed us to clearly observe the non-monotonic temperature behavior of the chemical potential near the critical point for the phase transition, a feature that characterizes also other superfluid systems, but that had never been observed before in weakly interacting Bose gases. The second part of this thesis work is devoted to the study of the dynamical processes that occur during the formation of the BEC order parameter within a thermal cloud. The cooling at finite rate across the Bose-Einstein condensation transition brings the system in a strongly out-of-equilibrium state, which is worth investigating, together with the subsequent relaxation towards an equilibrium state. This is of interest also in view of achieving a better understanding of second order phase transitions in general, since such phenomena are ubiquitous in nature and relevant also in other platforms for quantum technologies. A milestone result in the study of second order phase transitions is given by the Kibble-Zurek mechanism, which provides a simple model capturing important aspects of the evolution of a system that crosses a second-order phase transition at finite rate. It is based on the principle that in an extended system the symmetry breaking associated with a continuous phase transition can take place only locally. This causes the formation of causally disconnected domains of the order parameter, at the boundaries of which topological defects can form, whose number and size scale with the rate at which the transition is crossed, following a universal power law. It was originally developed in the context of cosmology, but was later successfully tested in a variety of systems, including superfluid helium, superconductors, trapped ions and ultracold atoms. The BEC phase transition represents in this context a paradigmatic test-bench, given the high degree of control at which this second-order phase transition can be crossed by means of cooling ramps at different rates. Already early experiments investigated the formation of the BEC order parameter within a thermal cloud, after quasi-instantaneous temperature quenches or very slow evaporative cooling. In the framework of directly testing the Kibble-Zurek mechanism, further experiments were performed, both in 2D and 3D systems, focusing on the emergence of coherence and on the statistics of the spontaneously generated topological defects as a function of the cooling rate. The Kibble-Zurek mechanism, however, does not fully describe the out-of-equilibrium dynamics of the system at the transition, nor the post-quench interaction mechanisms between domains that lead to coarse-graining. Most theoretical models are based on a direct linear variation of a single control parameter, e.g. the temperature, across the transition. In real experiments, the cooling process is controlled by the tuning of other experimental parameters and a global temperature might not even be well defined, in a thermodynamic sense, during the whole process. Moreover, the temperature variation is usually accompanied by the variation of other quantities, such as the number of atoms and the collisional rate, making it difficult to accurately describe the system and predict the post-quench properties. Recent works included effects going beyond the Kibble-Zurek mechanism, such as the inhomogeneity introduced by the trapping potential, the role of atom number losses, and the saturation of the number of defects for high cooling rates. These works motivate further studies, in particular of the dynamics taking place at early times, close to the crossing of the critical point. The aim of the work presented in this thesis is to further investigate the timescales associated to the formation and evolution of the BEC order parameter and its spatial fluctuations, as a function of the rate at which the transition point is crossed. We performed experiments producing BECs by means of cooling protocols that are commonly used in cold-atom laboratories, involving evaporative cooling in a magnetic trap. We explored a wide range of cooling rates across the transition and found a universal scaling for the growth of the BEC order parameter with the cooling rate and a finite delay in its formation. The latter was already observed in earlier works, but for a much more limited range of cooling rates. The evolution of the fluctuations of the order parameter was also investigated, with an analysis of the timescale of their decay during the relaxation of the system, from an initial strongly out-of-equilibrium condition to a final equilibrium state. This thesis is structured as follows: The first chapter presents the theoretical background, starting with a brief introduction to the concept of Bose Einstein condensation and a presentation of different models describing the thermodynamics of an equilibrium Bose gas. The second part of this chapter then deals with the out-of-equilibrium dynamics that is inevitably involved in the crossing of a second-order phase transition such as the one for Bose-Einstein condensation. The Kibble-Zurek mechanism is briefly reviewed and beyond KZ effects are pointed out, motivating a more detailed investigation of the timescales involved in the BEC formation. In the second chapter, I describe the experimental apparatus that we use to cool and confine the atoms. Particular detail is dedicated to the parts that have been upgraded during my PhD, such as the imaging system. In the third chapter I show our experimental results on the measurement of the equation of state of the weakly interacting uniform Bose gas at finite temperature. In the fourth chapter I present our results on the out-of-equilibrium dynamics in the formation of the condensate order parameter and its spatial fluctuations, as a function of different cooling rates.
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Msayib, Yunus. "Quantifying impaired metabolism following acute ischaemic stroke using chemical exchange saturation transfer magnetic resonance imaging." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:a98323ce-5998-436d-bca4-09df549cf191.

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In ischaemic stroke a disruption of cerebral blood flow leads to impaired metabolism and the formation of an ischaemic penumbra in which tissue at risk of infarction is sought for clinical intervention. In stroke trials, therapeutic intervention has largely been based on perfusion-weighted measures, but these have not been shown to be good predictors of tissue outcome. The aim of this thesis was to develop analysis techniques for magnetic resonance imaging (MRI) of chemical exchange saturation transfer (CEST) in order to quantify metabolic signals associated with tissue fate in patients with acute ischaemic stroke. This included addressing robustness for clinical application, and developing quantitative tools that allow exploration of the in-vivo complexity. Tissue-level analyses were performed on a dataset of 12 patients who had been admitted to the John Radcliffe Hospital in Oxford with acute ischaemic stroke and recruited into a clinical imaging study. Further characterisation of signals was performed on stroke models and tissue phantoms. A comparative study of CEST analysis techniques established a model-based approach, Bloch-McConnell model analysis, as the most robust for measuring pH-weighted signals in a clinical setting. Repeatability was improved by isolating non-CEST effects which attenuate signals of interest. The Bloch-McConnell model was developed further to explore whether more biologically-precise quantification of CEST effects was both possible and necessary. The additional model complexity, whilst more reflective of tissue biology, diminished contrast that distinguishes tissue fate, implying the biology is more complex than pH alone. The same model complexity could be used reveal signal patterns associated with tissue outcome that were otherwise obscured by competing CEST processes when observed through simpler models. Improved quantification techniques were demonstrated which were sufficiently robust to be used on clinical data, but also provided insight into the different biological processes at work in ischaemic tissue in the early stages of the disease. The complex array of competing processes in pathological tissue has underscored a need for analysis tools adequate for investigating these effects in the context of human imaging. The trends herein identified at the tissue level support the use of quantitative CEST MRI analysis as a clinical metabolic imaging tool in the investigation of ischaemic stroke.
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Mayboudi, LAYLA S. "Heat Transfer Modelling and Thermal Imaging Experiments in Laser Transmission Welding of Thermoplastics." Thesis, 2008. http://hdl.handle.net/1974/1551.

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This thesis presents a comprehensive study on the thermal modelling aspects of laser transmission welding of thermoplastics (LTW), a technology for joining of plastic parts. In the LTW technique, a laser beam passes through the laser-transmitting part and is absorbed within a thin layer in the laser-absorbing part. The heat generated at the interface of the two parts melts a thin layer of the plastic and, with applying appropriate clamping pressure, joining occurs. Transient thermal models for the LTW process were developed and solved by the finite element method (FEM). Input to the models included temperature-dependent thermo-physical properties that were adopted from well-known sources, material suppliers, or obtained by conducting experiments. In addition, experimental and theoretical studies were conducted to estimate the optical properties of the materials such as the absorption coefficient of the laser-absorbing part and light scattering by the laser-transmitting part. Lap-joint geometry was modelled for semi crystalline (polyamide - PA6) and amorphous (polycarbonate - PC) materials. The thermal models addressed the heating and cooling stages in a laser welding process with a stationary and moving laser beam. An automated ANSYS® script and MATLAB® codes made it possible to input a three-dimensional (3D), time-varying volumetric heat-generation term to model the absorption of a moving diode-laser beam. The result was a 3D time-transient, model of the laser transmission welding process implemented in the ANSYS® FEM environment. In the thermal imaging experiments, a stationary or moving laser beam was located in the proximity of the side surface of the two parts being joined in a lap-joint configuration. The side surface was then observed by the thermal imaging camera. For the case of the stationary beam, the laser was activated for 10 s while operating at a low power setting. For the case of the moving beam, the beam was translated parallel to the surface observed by the camera. The temperature distribution of a lap joint geometry exposed to a stationary and moving diode-laser beam, obtained from 3D thermal modelling was then compared with the thermal imaging observations. The predicted temperature distribution on the surface of the laser-absorbing part observed by the thermal camera agreed within 3C with that of the experimental results. Predicted temperatures on the laser-transmitting part surface were generally higher by 15C to 20C. This was attributed to absorption coefficient being set too high in the model for this part. Thermal imaging of the soot-coated laser-transmitting part surface indicated that significantly more scattering and less absorption takes place in this part than originally assumed. For the moving laser beam, good model match with the experiments (peak temperatures predicted within 1C) was obtained for some of the process conditions modelled for PA6 parts. In addition, a novel methodology was developed to extract the scattered laser beam power distribution from the thermal imaging observations of the moving laser beam.
Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2008-10-08 10:39:30.952
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(6577541), Long Yuan. "Spatial and Temporal Imaging of Exciton Dynamics and transport in two-dimensional Semiconductors and heterostructures by ultrafast transient absorption microscopy." Thesis, 2019.

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Recently, atomically thin two-dimensional (2D) layered materials such as graphene and transition metal dichalcogenides (TMDCs) have emerged as a new class of materials due to their unique electronic structures and optical properties at the nanoscale limit. 2D materials also hold great promises as building blocks for creating new heterostructures for optoelectronic applications such as atomically thin photovoltaics, light emitting diodes, and photodetectors. Understanding the fundamental photo-physics process in 2D semiconductors and heterostructures is critical for above-mentioned applications.
In Chapter 1, we briefly describe photo-generated charge carriers in two-dimensional (2D) transition metal dichalcogenides (TMDCs) semiconductors and heterostructures. Due to the reduced dielectric screening in the single-layer or few-layer of TMDCs semiconductors, Columbo interaction between electron and hole in the exciton is greatly enhanced that leads to extraordinary large exciton binding energy compared with bulk semiconductors. The environmental robust 2D excitons provide an ideal platform to study exciton properties in TMDCs semiconductors. Since layers in 2D materials are holding by weak van de Waals interaction, different 2D layers could be assembled together to make 2D heterostructures. The successful preparation of 2D heterostructures paves a new path to explore intriguing optoelectronic properties.
In Chapter 2, we introduce various optical microscopy techniques used in our work for the optical characterization of 2D semiconductors and heterostructures. These optical imaging tools with high spatial and temporal resolution allow us to directly track charge and energy flow at 2D interfaces.
Exciton recombination is a critical factor in determining the efficiency for optoelectronic applications such as semiconductor lasers and light-emitting diodes. Although exciton dynamics have been investigated in different 2D semiconductor, large variations in sample qualities due to different preparation methods have prevented obtaining intrinsic exciton lifetimes from being conclusively established. In Chapter 3, we study exciton dynamics in 2D TMDCs semiconductors using ultrafast PL and transient absorption microscopy. Here we employ 2D WS2 semiconductor as a model system to study exciton dynamics due to the low defect density and high quantum yield of WS2. We mainly focus on how the exciton population affects exciton dynamics. At low exciton density regime, we demonstrate how the interlayer between the bright and dark exciton populations influence exciton recombination. At high exciton density regime, we exhibit significant exciton-exciton annihilation in monolayer WS2. When comparing with the bilayer and trilayer WS2, the exciton-exciton annihilation rate in monolayer WS2 increases by two orders of magnitude due to enhanced many-body interactions at single layer limit.
Long-range transport of 2D excitons is desirable for optoelectronic applications based on TMDCs semiconductors. However, there still lacks a comprehensive understanding of the intrinsic limit for exciton transport in the TMDCs materials currently. In Chapter 4, we employ ultrafast transient absorption microscopy that is capable of imaging excitons transport with ~ 200 fs temporal resolution and ~ 50 nm spatial precision to track exciton motion in 2D WS2 with different thickness. Our results demonstrate that exciton mobility in single layer WS2 is largely limited by extrinsic factors such as charge impurities and surface phonons of the substrate. The intrinsic phonon-limited exciton transport is achieved in WS2 layers with a thickness greater than 20 layers.
Efficient photocarrier generation and separation at 2D interfaces remain a central challenge for many optoelectronic applications based on 2D heterostructures. The structural tunability of 2D nanostructures along with atomically thin and sharp 2D interfaces provides new opportunities for controlling charge transfer (CT) interactions at 2D interfaces. A largely unexplored question is how interlayer CT interactions contribute to interfacial photo-carrier generation and separation in 2D heterostructures. In Chapter 5, we present a joint experimental and theoretical study to address carrier generation from interlayer CT transitions in WS2-graphene heterostructures. We use spatially resolved ultrafast transient absorption microscopy to elucidate the role of interlayer coupling on charge transfer and photo-carrier generation in WS2-graphene heterostructures. These results demonstrate efficient broadband photo-carrier generation in WS2-graphene heterostructures which is highly desirable for atomically thin photovoltaic and photodetector applications based on graphene and 2D semiconductors.
CT exciton transport at heterointerfaces plays a critical role in light to electricity conversion using 2D heterostructures. One of the challenges is that direct measurements of CT exciton transport require quantitative information in both spatial and temporal domains. In order to address this challenge, we employ transient absorption microscopy (TAM) with high temporal and spatial resolution to image both bright and dark CT excitons in WS2-tetrance and CVD WS2-WSe2 heterostructure. In Chapter 6, we study the formation and transport of interlayer CT excitons in 2D WS2-Tetracene vdW heterostructures. TAM measurements of CT exciton transport at these 2D interfaces reveal coexistence of delocalized and localized CT excitons. The highly mobile delocalized CT excitons could be the key factor to overcome large CT exciton binding energy in achieving efficient charge separation. In Chapter 7, we study stacking orientational dependent interlayer exciton recombination and transport in CVD WS2-WSe2 heterostructures. Temperature-dependent interlayer exciton dynamics measurements suggest the existence of moiré potential that localizes interlayer excitons. TAM measurements of interlayer excitons transport reveal that CT excitons at WS2-WSe2 heterointerface are much more mobile than intralayer excitons of WS2. We attributed this to the dipole-dipole repulsion from bipolar interlayer excitons that efficiently screen the moiré potential fluctuations and facilitate interlayer exciton transport. Our results provide fundamental insights in understanding the influence of moiré potential on interlayer exciton dynamics and transport in CVD WS2-WSe2 heterostructures which has important implications in optoelectronic applications such as atomically thin photovoltaics and light harvesting devices.

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Книги з теми "Partial transfer absorption imaging"

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Daniel, Schlapfer, and United States. National Aeronautics and Space Administration., eds. Atmospheric pre-corrected differential absorption techniques to retrieve columnar water vapor: Application to AVIRIS 91/95 data. [Washington, D.C: National Aeronautics and Space Administration, 1996.

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2

Levien, Michael. From Primitive Accumulation to Regimes of Dispossession. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198792444.003.0003.

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In order to analyze land alienation in contemporary India, Shapan Adnan follows a theoretical approach in which mechanisms of primitive accumulation are not restricted to use of force, but include land transfer by agreement, as well as indirect mechanisms that are concerned with very different objectives. Reviewing evidence on land grabs, resistance, and workforce trends, he argues that primitive accumulation under neoliberal globalization has not been substantially followed by the absorption of the dispossessed in regular capitalist employment. Adnan puts forward a set of hypotheses to explain why the self-employed constituted at least half or more of the Indian workforce over 1999–2012. While such trends indicate a partial and short-run divergence from the classic Marxian schema of the transition to capitalism, Adnan argues that, given ongoing trends in the national and global economy, the long run outcome in India remains an open question.
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Частини книг з теми "Partial transfer absorption imaging"

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Nakanishi, Tomoko M. "Real-Time Water Movement in a Plant." In Novel Plant Imaging and Analysis, 39–72. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4992-6_2.

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AbstractThe next approach to research on water was to measure the small amount of water actually moving within a plant. The best method is to utilize radioisotope (RI)-labeled water and measure the radiation from outside of the plant. However, it is rather difficult to label water, since there are only limited kinds of RI for tracing water.When utilizing 18F to trace water movement, another fundamental question to consider was the features that characterize drought-tolerant and drought-sensitive plants. It is natural to suppose that drought-tolerant plants have strong water absorption; therefore, by analyzing the water absorption mechanism of tolerant plants and by introducing this function to sensitive plants, it might be possible to make the sensitive plants more tolerant.However, when water uptake was studied in naturally developed drought-tolerant and drought-sensitive cowpea, selected from 2000 cowpea plants grown in the field of Africa, the result was unexpected. Under normal conditions, the amount of water absorbed by the drought-tolerant strain was much lower than that absorbed by the sensitive strain, as if showing the low capability of water absorption. When a drought condition was introduced, the tolerant strain began to absorb much more water than usual, whereas the sensitive strain could not absorb as much water as before. This result provided us with an important lesson. Analyzing the mechanism of drought tolerance only by comparing the water absorption of tolerant and sensitive plants might not readily reveal the reason for drought tolerance. The features of the naturally produced plants showed us different mechanisms that might not match our expectations developed in the laboratory.Next, we performed water measurements using 15O-labeled water, which has an extremely short half-life of 2 minutes. Here, we found another astonishing result, which was “water circulation” in the plant internode. A tremendous amount of water was always leaking from xylem cells, which had been regarded as a mere pipe to transfer water from the root to the aboveground parts. In another subsequent study, it was shown that the water flowing out from the xylem was pushing out the water already present in the stem and then returning to the xylem again to move upward. The water velocity in the internode was kept constant, and through simulation, it took less than 20 minutes to exchange the water already present in the stem with newly absorbed water.
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Nakanishi, Tomoko M. "Element-Specific Distribution in a Plant." In Novel Plant Imaging and Analysis, 75–107. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4992-6_3.

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AbstractFor the first stage of the study of the elements, the distribution of the element within the plant tissue was presented employing neutron activation analysis (NAA). Since NAA allows nondestructive analysis of the elements in the sample, this is the only method to measure the absolute amount of elements in the sample.The results showed that the element-specific profile varied throughout the whole plant, and this distribution tendency remained similar throughout development. There were many junctions of element-specific concentrations between the tissues, suggesting barriers to the movement of the elements. Generally, heavy elements tended to accumulate in roots, except for Mn and Cr. Of the elements measured, Ca and Mg showed changes in concentration with the circadian rhythm. Since the amount of the element in a plant reflects the features of the soil where the plant grows, multielement analysis of the plant could specify the site of the agricultural products produced.Before addressing the development of a real-time RI imaging system (RRIS), the production of RIs for essential elements for plant nutrition, 28Mg and 42K, is presented. The reason why concentrating on RIs is because when we examine the history of plant research, physiological research on the elements without available radioisotopes has not been well developed. For example, the boron (B) transporter was recently found and the study of B in plants is far behind compared to the other elements.Therefore, we developed a preparation method for elements whose available RIs were not previously employed in plant research, 28Mg and 42K. They are the radioisotopes we prepared and a root absorption study using 28Mg as a tracer is presented as an example. It was found that the orientation of Mg transfer was different according to the site of the root where Mg was absorbed. The specific role of Mg has not yet been clarified by florescent imaging because the overwhelming amount of Ca makes it difficult to distinguish Mg and Ca.
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Serbin, Shawn P., and Philip A. Townsend. "Scaling Functional Traits from Leaves to Canopies." In Remote Sensing of Plant Biodiversity, 43–82. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-33157-3_3.

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AbstractIn this chapter, we begin by exploring the relationship between plant functional traits and functional diversity and how this relates to the characterization and monitoring of global plant biodiversity. We then discuss the connection between leaf functional traits and their resulting optical properties (i.e., reflectance, transmittance, and absorption) and how this related to remote sensing (RS) of functional diversity. Building on this, we briefly discuss the history of RS of functional traits using spectroscopy and imaging spectroscopy data. We include a discussion of the key considerations with the use of imaging spectroscopy data for scaling and mapping plant functional traits across diverse landscapes. From here we provide a review of the general methods for scaling and mapping functional traits, including empirical and radiative transfer model (RTM) approaches. We complete the chapter with a discussion of other key considerations, such as field sampling protocols, as well as current caveats and future opportunities.
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"Effects of Electromagnetic Fields on Specific Absorption Rate and Heat Transfer in the Human Eye." In Ophthalmological Imaging and Applications, 446–67. CRC Press, 2014. http://dx.doi.org/10.1201/b17026-26.

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S., Sebastin, and Murali Ram Kumar S. M. "Use of Eggshell as a Partial Replacement for Sand in Concrete Used in Biomedical Applications." In Deep Neural Networks for Multimodal Imaging and Biomedical Applications, 256–64. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-3591-2.ch016.

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The recent researches show that cement mortar containing eggshell as a partial replacement of sand contained radiation absorption property. In these cement mortar samples, 5%, 10%, 15%, and 20% by mass of sand was replaced by crushed eggshells, and there was increase in radiation absorption. The result also showed that using eggshell as a partial replacement for sand leads to decrease in compressive strength of the cement mortar. Waste of any kind in the environment when its concentration is in excess can become a critical factor for humans, animals, and vegetation. The utilization of the waste is a priority today in order to achieve sustainable development. So, we have planned to increase that compressive strength by means of using seashell as a partial replacement for cement. The main objective of the project is to maintain radiation absorption by means of using eggshell along with seashell as a partial replacement for cement to increase the compressive strength.
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"Bio-Mediated Synthesis of Quantum Dots for Fluorescent Biosensing and Bio-Imaging Applications." In Materials Research Foundations, 185–223. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901571-7.

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Quantum dots (QDs) have received great attention for development of novel fluorescent nanoprobe with tunable colors towards the near-infrared (NIR) region because of their unique optical and electronic properties such as luminescence characteristics, wide range, continuous absorption spectra and narrow emission spectra with high light stability. Quantum dots are promising materials for biosensing and single molecular bio-imaging application due to their excellent photophysical properties such as strong brightness and resistance to photobleaching. However, the use of quantum dots in biomedical applications is limited due to their toxicity. Recently, the development of novel and safe alternative method, the biomediated greener approach is one of the best aspects for synthesis of quantum dots. In this Chapter, biomediated synthesis of quantum dots by living organisms and biomimetic systems were highlighted. Quantum dots based fluorescent probes utilizing resonance energy transfer (RET), especially Förster resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET) and chemiluminescence resonance energy transfer (CRET) to probe biological phenomena were discussed. In addition, quantum dot nanocomposites are promising ultrasensitive bioimaging probe for in vivo multicolor, multimodal, multiplex and NIR deep tissue imaging. Finally, this chapter provides a conclusion with future perspectives of this field.
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Sharma, Arpit Kumar, Amita Nandal, Liang Zhou, Arvind Dhaka, and Tao Wu. "Brain Tumor Classification Using Modified VGG Model-Based Transfer Learning Approach." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2021. http://dx.doi.org/10.3233/faia210051.

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This paper presents the detection of brain tumors by using the VGG16 approach for grading from multiphase MRI images. It also depicts the comparative analysis among several outcomes coming from different baseline neural networks and deep learning configurations. Machine learning directly uses MRI images, with few sequential operations among multiphase MRIs. This paper illustrates the process that influences the potential of the deep learning machine. Neural networks generally involve the convolutional neural networks (CNN) for achieving the optimum enhancement on grading performance. Such processes also include visualization of kernels trained in several layers and visualize few self-learned features attained from CNN. Such research shows the deep learning approach with its applications in brain tumor segmentation. Researchers found difficulty in the automatic segmentation of brain tumors that provide great variability in sizes and shapes. Computed tomography (CT) and magnetic resonance (MR) imaging are the most widely used radiographic techniques in diagnosis, clinical studies, and treatment planning. The problems common to both CT and MR medical images are partial volume effect, different artifacts: example motion artifacts, ring artifacts, etc, and noise due to sensors and related electronic systems. In this paper, we propose an easy and unique segmentation process that provides competitive performance as well as speedy runtime for the evaluation of model performance in terms of loss and accuracy.
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Kumar, Pramod, and Sushil Kumar. "Detection of Bio-Relevant Metal Ions by Luminescent Ru(II)-Polypyridyl Based Sensors." In Ruthenium - an Element Loved by Researchers [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96453.

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Biorelevant metal ions such as Cu2+ and Fe2+/Fe3+ participate in various biological events which include electron transfer reactions, delivery and uptake of oxygen, DNA and RNA syntheses, and enzymatic catalysis to maintain fundamental physiological processes in living organisms. So far, several analytical techniques have been investigated for their precise detection; however, luminescence-based sensing is often superior due to its high sensitivity, selectivity, fast and easy operation and convenient cellular imaging. Owing to their immense photophysical and photochemical properties stemming from large Stokes shift, absorption in visible region, good photostability and long excited state lifetimes, Ru(II)-polypyridyl-based complexes have gained increasing interest as luminophores. Over past few decades, several Ru(II)-polypyridyl based chemosensors have rapidly been developed for detection of different biorelevant and other metal ions. The main object of this book chapter is to cover a majority of Ru(II)-polypyridyl based chemosensors showing a selective and sensitive detection of bio-relevant Cu2+ and Fe2+/Fe3+ ions. The photophysical properties of Ru(II) complexes, detection of metal ions, sensing mechanism and applications of these sensors are discussed at a length.
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Murphy, Elaine. "Cognitive and Behavioral Manifestations of Disorders of Homocysteine Metabolism." In Cognitive and Behavioral Abnormalities of Pediatric Diseases. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195342680.003.0041.

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This chapter reviews the metabolism of homocysteine and its associated defects, focusing on the clinical manifestations of cognitive and behavioral disturbances. The terminology of homocysteine and its derivatives can be confusing, so I begin by clarifying that. Next, the metabolism of homocysteine is outlined, followed by discussion of the disorders of homocysteine transsulfuration. Vitamin B12 (cobalamin, CBL) is important in the effective metabolism of homocysteine and thus defects of CBL absorption, transport, and intracellular transport are also discussed. Finally, disorders of remethylation of methionine will be described. Diagnostic criteria, imaging results, and the pathophysiology of these disorders are also considered. The terminology related to homocysteine metabolism can be confusing. In 2000, a consensus statement on homocysteine nomenclature was published (Mudd et al. 2000). Normal human plasma contains total concentrations of homocysteine and its derivative disulfides of less than 15 μmol/L, although there is some variation due to genetic and other factors. Of this total, only 1%–2% occurs as the thiol (i.e., sulfhydryl) containing amino acid homocysteine. The remaining 98% is in the form of disulfides. Approximately 75%–80% of the total is bound to protein through disulfide bonds with protein cysteines, mainly in albumin, whereas the remainder occurs in non–protein-bound or free forms: the disulfide homocystine-homocystine (Hcy-Hcy), homocysteine-cysteine mixed disulphide, and minor amounts of other mixed disulfides. Together all these moieties make up what is referred to as total homocysteine (tHcy). As all these disulfide bonds can be cleaved by reducing agents, giving the thiol homocysteine, this allows measurement of tHcy as the sum of any thiol homocysteine originally present plus that originally present as a disulfide. In patients with homocystinuria, the percentage contribution of the thiol homocysteine to the total of these forms in plasma rises, reaching 10%–25% as the total homocysteine concentration reaches 150–400 μmol/L. The methionine/homocysteine cycle, also known as the single carbon transfer pathway, is found in all tissues and can broadly be divided into transsulfuration and remethylation components. The cycle aims to conserve methionine and provide sufficient S-adenosylmethionine (AdoMet) for vital transmethylation reactions.
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Тези доповідей конференцій з теми "Partial transfer absorption imaging"

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Liu, Chang H., and Ben Q. Li. "Absorption and Scattering of the Aggregated Multi-Layered Nanoshells." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44492.

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A generalized mathematical formulation is presented for multi-scattering of electromagnetic fields by an ensemble consisting of arbitrarily-positioned multilayered nanoshells. The model is developed by combining the addition theorem and the efficient recursive procedure for multilayered nanoshells and general procedures for computing the multiple scattered fields and optical properties of the particle ensemble are presented. The enhancement of the electric field and the energy absorbed by the aggregated silica-gold nanoshell and gold-silica-gold nanoshells are analyzed to understand the physics governing the electromagnetic field interaction with aggregated multilayered nanoshells. The mathematical model should be helpful in providing valuable information on optical and radative transfer characteristics needed for the nanoshell-based applications in photothermal therapy, biomedical imaging, biosensing and waveguide for energy transport.
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2

Kearney, Sean P., Thomas W. Grasser, and Steven J. Beresh. "Filtered Rayleigh Scattering Thermometry in a Premixed Sooting Flame." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56894.

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Filtered Rayleigh Scattering (FRS) is demonstrated in a premixed, sooting ethylene-air flame. In sooting flames, traditional laser-based temperature-imaging techniques such linear (unfiltered) Rayleigh scatting (LRS) and planar laser-induced fluorescence (PLIF) are rendered intractable due to intense elastic scattering interferences from in-flame soot. FRS partially overcomes this limitation by utilizing a molecular iodine filter in conjunction with an injection-seeded Nd:YAG laser, where the seeded laser output is tuned to line center of a strong iodine absorption transition. A significant portion of the Doppler-broadened molecular Rayleigh signal is then passed while intense soot scattering at the laser line is strongly absorbed. In this paper, we demonstrate the feasibility of FRS for sooting flame thermometry using a premixed, ethylene-air flat flame. We present filtered and unfiltered laser light-scattering images, FRS temperature data, and laser-induced incandescence (LII) measurements of soot volume fraction for fuel-air equivalence ratios of φ = 2.19 and 2.24. FRS-measured product temperatures for these flames are nominally 1500 K. The FRS temperature and image data are discussed in the context of the soot LII results and a preliminary estimate of the upper sooting limit for our FRS system of order 0.1 ppm volume fraction is obtained.
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Chen, Kok Hao, and Jong Hyun Choi. "DNA Oligonucleotide-Templated Nanocrystals: Synthesis and Novel Label-Free Protein Detection." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11958.

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Semiconductor and magnetic nanoparticles hold unique optical and magnetic properties, and great promise for bio-imaging and therapeutic applications. As part of their stable synthesis, the nanocrystal surfaces are usually capped by long chain organic moieties such as trioctylphosphine oxide. This capping serves two purposes: it saturates dangling bonds at the exposed crystalline lattice, and it prevents irreversible aggregation by stabilizing the colloid through entropic repulsion. These nanocrystals can be rendered water-soluble by either ligand exchange or overcoating, which hampers their widespread use in biological imaging and biomedical therapeutics. Here, we report a novel scheme of synthesizing fluorescent PbS and magnetic Fe3O4 nanoparticles using DNA oligonucleotides. Our method of PbS synthesis includes addition of Na2S to the mixture solution of DNA sequence and Pb acetate (at a fixed molar ratio of DNA/S2−/Pb2+ of 1:2:4) in a standard TAE buffer at room temperature in the open air. In the case of Fe3O4 particle synthesis, ferric and ferrous chloride were mixed with DNA in DI water at a molar ratio of DNA/Fe2+/Fe3+ = 1:4:8 and the particles were formed via reductive precipitation, induced by increasing pH to ∼11 with addition of ammonium hydroxide. These nanocrystals are highly stable and water-soluble immediately after the synthesis, due to DNA termination. We examined the surface chemistry between oligonucleotides and nanocrystals using FTIR spectroscopy, and found that the different chemical moieties of nucleobases passivate the particle surface. Strong coordination of primary amine and carbonyl groups provides the chemical and colloidal stabilities, leading to high particle yields (Figure 1). The resulting PbS nanocrystals have a distribution of 3–6 nm in diameter, while a broader size distribution is observed with Fe3O4 nanoparticles as shown in Figure 1b and c, respectively. A similar observation was reported with the pH change-induced Fe3O4 particles of a bimodal size distribution where superparamagnetic and ferrimagnetic magnetites co-exist. In spite of the differences, FTIR measurements suggest that the chemical nature of the oligonucleotide stabilization in this case is identical to the PbS system. As a particular application, we demonstrate that aptamer-capped PbS QD can detect a target protein based on selective charge transfer, since the oligonucleotide-templated synthesis can also serve the additional purpose of providing selective binding to a molecular target. Here, we use thrombin and a thrombin-binding aptamer as a model system. These QD have diameters of 3∼6 nm and fluoresce around 1050 nm. We find that a DNA aptamer can passivate near IR fluorescent PbS nanocrystals, rendering them water-soluble and stable against aggregation, and retain the secondary conformation needed to selectively bind to its target, thrombin, as shown in Figure 2. Importantly, we find that when the aptamer-functionalized nanoparticles binds to its target (only the target), there is a highly systematic and selective quenching of the PL, even in high concentrations of interfering proteins as shown in Figure 3a and b. Thrombin is detected within one minute with a detection limit of ∼1 nM. This PL quenching is attributed to charge transfer from functional groups on the protein to the nanocrystals. A charge transfer can suppress optical transition mechanisms as we observe a significant decrease in QD absorption with target addition (Figure 3c). Here, we rule out other possibilities including Forster resonance energy transfer (FRET) and particle aggregation, because thrombin absorb only in the UV, and we did not observe any significant change in the diffusion coefficient of the particles with the target analyte, respectively. The charge transfer-induced photobleaching of QD and carbon nanotubes was observed with amine groups, Ru-based complexes, and azobenzene compounds. This selective detection of an unlabeled protein is distinct from previously reported schemes utilizing electrochemistry, absorption, and FRET. In this scheme, the target detection by a unique, direct PL transduction is observed even in the presence of high background concentrations of interfering negatively or positively charged proteins. This mechanism is the first to selectively modulate the QD PL directly, enabling new types of label free assays and detection schemes. This direct optical transduction is possible due to oligonucleotidetemplated surface passivation and molecular recognition. This chemistry may lead to more nanoparticle-based optical and magnetic probes that can be activated in a highly chemoselective manner.
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Ding, Jiachen, Ping Yang, Michael D. King, Steven Platnick, Kerry G. Meyer, and Chenxi Wang. "A Gas Absorption Parameterization Model for Hyperspectral Shortwave Radiative Transfer Computations." In Hyperspectral Imaging and Sounding of the Environment. Washington, D.C.: OSA, 2019. http://dx.doi.org/10.1364/hise.2019.hw5c.4.

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Kakuta, Naoto, Kenta Yamada, Ryota Fujioka, Katsuya Kondo, Hidenobu Arimoto, and Yukio Yamada. "Temperature Imaging of Water Around a Small Heated Sphere Using a Near-Infrared Absorption Technique." In The 15th International Heat Transfer Conference. Connecticut: Begellhouse, 2014. http://dx.doi.org/10.1615/ihtc15.min.008855.

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Jung, Mi-Rim, Eun-A. Kwak, Hye-Keun Oh, Seong-Bo Shim, Na-Rak Choi, and Jai-Soon Kim. "Evaluation of partial coherent imaging using the transfer function in immersion lithography." In SPIE 31st International Symposium on Advanced Lithography, edited by Donis G. Flagello. SPIE, 2006. http://dx.doi.org/10.1117/12.656983.

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Najjaran Kheirabadi, Ahmad, James Freeman, Alba Ramos Cabal, and Christos N. Markides. "Experimental Investigation of an Ammonia-Water Diffusion-Absorption Refrigerator (DAR) at Part Load." In ASME 2017 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/ht2017-4830.

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Diffusion absorption refrigeration (DAR) cycles enable passive fully thermally-driven refrigeration for off-grid purposes. Typically, DAR units are designed for a given heat supply load and temperature, although real operation inevitably involves unsteady variations in these inputs. In this study, a thermally-driven DAR unit with a nominal cooling capacity of 120 W is connected to an electric heat source. The working fluid is ammonia-water NH3/H2O, with hydrogen (H2) added as an auxiliary gas to keep the system pressure constant and to decrease the partial pressure of the refrigerant (ammonia) in the evaporator. A control unit is used to adjust and measure the input heat-source power applied to the unit. The operating pressure of the system is 20.7 bar, the ambient temperature is 22 °C and the input thermal power is in the range 250 to 700 W. The cooling capacity of the unit and the input heat load are measured simultaneously at different operation conditions. To measure the cooling power, a cold box is constructed around the evaporator, and a second heater is located inside the cold box which sets the cold space temperature equal to that of the ambient. This allows the coefficient of performance (COP) to be evaluated. The COP and cooling capacity of the unit are investigated at part load by varying the heat supply, from which maximum values are obtained (0.28 and 110 W, respectively). Finally, experimental results are compared to the theoretical predictions from a thermodynamic model of a DAR cycle. Once validated, the model is also used to find the properties of the fluid mixture in different states in the DAR cycle.
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Carvajal, Ignacio, Rita Aguilar, and Alejandro Zacarias. "Heat transfer study in the elements of an absorption refrigeration system operating to partial heat loads to generator." In Thermal Sciences 2004. Proceedings of the ASME - ZSIS International Thermal Science Seminar II. Connecticut: Begellhouse, 2004. http://dx.doi.org/10.1615/ichmt.2004.intthermscisemin.430.

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Kauranen, P., H. M. Hertz, and S. Svanberg. "Two-tone frequency-modulation spectroscopy for low-absorption tomographic imaging." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/cleo_europe.1994.cmi3.

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Non-intrusive spatially resolved measurements of gas concentrations are important in fluid flow, combustion, and heat transfer research. By combining multi-angle absorption measurements with tomographic reconstruction, quantitative and spatially resolved measurements may be performed.1 Due to the low absorbance of most gaseous species in the visible wavelength region, previous attempts in optical absorption tomography have been restricted to specially selected species in order to obtain a sufficiently high signal-to-noise ratio for the tomographic reconstruction. We combine tomography with two-tone frequency modulation spectroscopy (TTFMS), a highly sensitive absorption technique, extending the possibilities for quantitative and spatially resolved measurements to a vast number of species.2 Our TTFMS experiment uses laser modulation at 647 ± 5.2 MHz and has an absorption sensitivity of 1:106. The tomographic method is demonstrated by mapping the concentration in a section of a weakly absorbing O2 gas flow, using a GaAlAs diode laser operating around 760 nm.
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Fan, Jintu, and Xiaoyin Cheng. "A Numerical and Experimental Study of Heat and Moisture Transfer With Phase Change and Mobile Condensates in Fibrous Insulation." In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47597.

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This paper reports on an improved model of coupled heat and moisture transfer with phase change and mobile condensates in fibrous insulation. The new model considered the moisture movement induced by the partial water vapor pressure, a super saturation state in condensing region as well as the dynamic moisture absorption of fibrous materials and the movement of liquid condensates. The results of the new model were compared and found in good agreement with the experimental ones. Numerical simulation was carried using the model to investigate the effect of various material parameters on the transport phenomena.
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Звіти організацій з теми "Partial transfer absorption imaging"

1

Bonfil, David J., Daniel S. Long, and Yafit Cohen. Remote Sensing of Crop Physiological Parameters for Improved Nitrogen Management in Semi-Arid Wheat Production Systems. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7696531.bard.

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To reduce financial risk and N losses to the environment, fertilization methods are needed that improve NUE and increase the quality of wheat. In the literature, ample attention is given to grid-based and zone-based soil testing to determine the soil N available early in the growing season. Plus, information is available on in-season N topdressing applications as a means of improving GPC. However, the vast majority of research has focused on wheat that is grown under N limiting conditions in sub-humid regions and irrigated fields. Less attention has been given to wheat in dryland that is water limited. The objectives of this study were to: (1) determine accuracy in determining GPC of HRSW in Israel and SWWW in Oregon using on-combine optical sensors under field conditions; (2) develop a quantitative relationship between image spectral reflectance and effective crop physiological parameters; (3) develop an operational precision N management procedure that combines variable-rate N recommendations at planting as derived from maps of grain yield, GPC, and test weight; and at mid-season as derived from quantitative relationships, remote sensing, and the DSS; and (4) address the economic and technology-transfer aspects of producers’ needs. Results from the research suggest that optical sensing and the DSS can be used for estimating the N status of dryland wheat and deciding whether additional N is needed to improve GPC. Significant findings include: 1. In-line NIR reflectance spectroscopy can be used to rapidly and accurately (SEP <5.0 mg g⁻¹) measure GPC of a grain stream conveyed by an auger. 2. On-combine NIR spectroscopy can be used to accurately estimate (R² < 0.88) grain test weight across fields. 3. Precision N management based on N removal increases GPC, grain yield, and profitability in rainfed wheat. 4. Hyperspectral SI and partial least squares (PLS) models have excellent potential for estimation of biomass, and water and N contents of wheat. 5. A novel heading index can be used to monitor spike emergence of wheat with classification accuracy between 53 and 83%. 6. Index MCARI/MTVI2 promises to improve remote sensing of wheat N status where water- not soil N fertility, is the main driver of plant growth. Important features include: (a) computable from commercial aerospace imagery that include the red edge waveband, (b) sensitive to Chl and resistant to variation in crop biomass, and (c) accommodates variation in soil reflectance. Findings #1 and #2 above enable growers to further implement an efficient, low cost PNM approach using commercially available on-combine optical sensors. Finding #3 suggests that profit opportunities may exist from PNM based on information from on-combine sensing and aerospace remote sensing. Finding #4, with its emphasis on data retrieval and accuracy, enhances the potential usefulness of a DSS as a tool for field crop management. Finding #5 enables land managers to use a DSS to ascertain at mid-season whether a wheat crop should be harvested for grain or forage. Finding #6a expands potential commercial opportunities of MS imagery and thus has special importance to a majority of aerospace imaging firms specializing in the acquisition and utilization of these data. Finding #6b on index MCARI/MVTI2 has great potential to expand use of ground-based sensing and in-season N management to millions of hectares of land in semiarid environments where water- not N, is the main determinant of grain yield. Finding #6c demonstrates that MCARI/MTVI2 may alleviate the requirement of multiple N-rich reference strips to account for soil differences within farm fields. This simplicity will be less demanding of grower resources, promising substantially greater acceptance of sensing technologies for in-season N management.
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