Search

Composite sandwich constructions are very widely employed in the modern aircraft industry, honeycomb panels among them. The principal defects of honeycomb sandwiches are cover detachment because of cell collapse or poor adhesive, which can lead to water penetration in cells. Recently, the thermal method of non-destructive testing (infrared thermography) has begun to be applied to the diagnostics of honeycomb constructions, and has some advantages over traditional methods. However, thermal processes are transient, and this complicates the selection of optimal parameters for monitoring. The purpose of this work is to investigate the possibilities of the thermal method for honeycomb panel inspection using computer simulation. The COMSOL Multiphysics package was used for the simulations. A 3D model of the honeycomb panel was proposed, and two possible defects considered: the detachment of the panel cover from the filler and the presence of water in the defective cell. The implementation of the proposed 3D model made it possible to investigate the effect of a defect on the thermal field of the panel surface. The simulation results showed that optimal testing time is significantly different for various types of panels. The correct selection of testing parameters increases the accuracy of the testing procedure. The results of experimental investigation confirmed the adequacy of the proposed model for thermal testing.

We have studied IR-induced low-frequency coherent vibration of an intramolecularly hydrogen-bonded molecule, quinizarin, by an ultrashort IR-pump-visible-probe spectroscopy with ∼60 fs time resolution. In this experiment, the IR excitation of the symmetric OH-stretching mode induced a low-frequency vibrational coherence, which was then detected as an oscillation of the visible absorption intensity. The observed oscillation was assigned to a “hydrogen-bond modulating” vibration by the vibrational analysis based on the density functional theory (DFT). Because the vibrational coherence formation by IR excitation requires a substantial anharmonic coupling, we carried out a DFT-based numerical analysis of the anharmonic coupling between the OH-stretching and the low-frequency mode, by evaluating the transition moment of the combination band. We took account of two types of anharmonicities, i.e., the mechanical anharmonicity and the electrical anharmonicity. Although the electrical anharmonicity is often neglected, it was found that the electrical anharmonicity had a comparable contribution to the mechanical anharmonicity, in generation of vibrational coherence of the low-frequency mode in this system. This result indicates general importance of the electrical anharmonicity in strongly hydrogen-bonded systems. [ABSTRACT FROM AUTHOR]

Sonic infrared is potentially a very attractive nondestructive evaluation technique offering the possibility of rapid testing of complex components. However, at present it is difficult to be sure that sufficient excitation has been applied so that a null (no defect present) result can be trusted. This paper presents a calibration method to improve the reliability of the technique. The method uses a measurement of the vibration of the component during the test, the vibration signal being processed to give a “heating index” which is a measure of the ability of the vibration field to generate heat at any defects of interest that are present. The calculation of the heating index and the rationale for its formulation are described. The method is then applied on two sets of beamlike specimens with cracks of different sizes. The maximum temperature rise in successive tests on a given specimen is shown to correlate well with the maximum heating index, so validating the method. The threshold heating index required to reliably detect cracks as a function of crack size is discussed and practical calibration and test procedures are proposed. [ABSTRACT FROM AUTHOR]

Plasma polymerized polydimethylsiloxane films irradiated under different partial pressures of oxygen with a 172 nm vacuum ultraviolet light were investigated in order to clarify the roles of molecular oxygen and photons in photooxidation. The thickness, densities, surface roughness, elemental compositions, and molecular structures of the irradiated and unirradiated films were examined by using glazing incidence x-ray reflectivity, Rutherford backscattering, infrared, and x-ray absorption (XAS) spectroscopies. Photooxidation is hardly promoted by irradiation in a high vacuum of 1×10-4 Pa, though photodesorption of the methyl group and formation of Si–H bonds were observed. Silica films thicker than 140 nm were formed at room temperature by irradiating them in low pressure oxygen gases. The degree of oxidation was smaller for the oxygen pressure of 10 kPa than for 83 Pa. Si K-edge XAS was performed to clarify the change of coordination environment of silicon by photooxidation in dilute oxygen flow containing less than 5 ppm of molecular oxygen. [ABSTRACT FROM AUTHOR]

Climate is a topic of great concern to students, but it remains difficult to discuss scientifically. We are bombarded daily by emotional messaging for and against the proposition that human activities are altering the climate in ways that may have catastrophic effects. But it often seems that those predictions rest entirely on massive computer simulation models, which the listener is not in a position to evaluate. We wished to find an aspect of the puzzle that could be directly experienced, and that would therefore give us a solid starting point for discussion. Here we describe a dramatic lecture demonstration that scales well for large audiences and that requires as little as 10 classroom minutes to show an important difference between room air and carbon dioxide gas. Beyond its significance for public policy, the demonstration can serve as a springboard to motivate discussion of important physics concepts such as molecular rotation and vibration spectra. [ABSTRACT FROM AUTHOR]

The article presents the research conducted on Van der Waals (vdW) materials that provide platform for strong light-matter interaction enabled by their polaritonic modes and the deep subwavelength light confinement. Semiconductor vdW materials such as WSe2 offers photonic and quantum integrated technologies and sustain visible–near-infrared (VIS-NIR) exciton-polariton (EP) modes at room temperature.

Interest in the conservation of paintings grows year by year. Their periodic inspection is essential for their conservation over the time. Thermographic non-destructive inspection is one technique useful for paintings, but it is essential to be able to detect buried defects while minimising the level of thermal stimulus. This paper describes a pulse-compression infrared thermography technique whereby defect detection is optimized while minimising the rise in temperature. To accomplish this task, LED lamps driven by a coded waveform based on a linear frequency modulated chirp signal have been used on paintings on both a wooden panel and a canvas layer. These specimens contained artificially fabricated defects. Although the physical condition of each painting was different, the experimental results show that the proposed signal processing procedure is able to detect defects using a low temperature contrast. [ABSTRACT FROM AUTHOR]

Fibre Metal Laminates (FMLs) describe a number of aerospace-grade layered structural materials where thin metal alloy foils are interleaved with Fibre Reinforced Polymer (FRP) plies. Such material hybridisation at the layer meso-scale poses a challenge for non-destructive testing (NDT). On the other hand, the need for NDT inspection of FMLs arises due to the potential development of interlayers disbonds, both during fabrication or in-service. This work describes the successful implementation of two Infrared-NDT approaches to evaluate a defected FML panel made of Titanium/Graphite (Ti-Gr). One technique is based on the modulation of the deployed heat from a low-cost halogen lamp, to retrieve defects as phase-contrast signatures from harmonics in the frequency domain. The second technique uses a flying laser heat-source, raster scanning the surface, searching for defect signatures on the heat distribution trail of the moving laser. The work explores also the opportunity to collimate the laser heat source as a round spot or a linear distribution. The proposed non-conventional IR-NDT approaches are also compared with a well-established Pulsed Phase Thermography (PPT) algorithm, demonstrating a similar ability of defects evaluation, but offering some favourable features, which are highlighted in the work. [ABSTRACT FROM AUTHOR]

Composite sandwich constructions are very widely employed in the modern aircraft industry, honeycomb panels among them. The principal defects of honeycomb sandwiches are cover detachment because of cell collapse or poor adhesive, which can lead to water penetration in cells. Recently, the thermal method of non-destructive testing (infrared thermography) has begun to be applied to the diagnostics of honeycomb constructions, and has some advantages over traditional methods. However, thermal processes are transient, and this complicates the selection of optimal parameters for monitoring. The purpose of this work is to investigate the possibilities of the thermal method for honeycomb panel inspection using computer simulation. The COMSOL Multiphysics package was used for the simulations. A 3D model of the honeycomb panel was proposed, and two possible defects considered: the detachment of the panel cover from the filler and the presence of water in the defective cell. The implementation of the proposed 3D model made it possible to investigate the effect of a defect on the thermal field of the panel surface. The simulation results showed that optimal testing time is significantly different for various types of panels. The correct selection of testing parameters increases the accuracy of the testing procedure. The results of experimental investigation confirmed the adequacy of the proposed model for thermal testing. [ABSTRACT FROM AUTHOR]

Temperature distribution in nonaxisymmetrically concentrating solar thermal receivers tubes is calculated for the steady-state solution with a Gauss-Seidel iteration in cylindrical coordinates. The classical plane-biharmonic thermoelastic approach to nonaxisymmetrically heated tube stress is applied. Calculation of the dominant axial thermal stress component is included. Validation is obtained with the linear-elastic thermal stress OpenFOAM® solver. Thermoelastic stress in stainless steel 316 Schedule 5S DN25 (1″) tubes containing liquid sodium is found to be 35% lower than in tubes containing molten salt. The difference is due to the higher conductivity of liquid sodium which maintains a smaller temperature difference between the front and back tube sides. A simplified thermal stress formula is shown to be erroneous if not implemented as originally documented. The sensitivity of tube thermoelastic stress to tube material and flow properties is illustrated with parameter variation, and the impact of solar concentrated heat flux is explored with some typical and ideal tube circumference flux profiles. [ABSTRACT FROM AUTHOR]

Synthesis and characterizations of novel conducting polymer film based on poly(carbazoyltriphenylamine) (poly(CBZ-TPA)) were studied. Additionally, copolymer film based on CBZ-TPA and thiophene (Th) was also obtained by electrochemical polymerization. Electrochromic properties of poly(CBZ-TPA) and poly(CBZ-TPA-Th) films were investigated by cyclic voltammetry and double step potential chronoamperometry. Optical properties of the two films were characterized by UV–vis spectrophotometer and FT-IR spectrometer. Different colors of poly(CBZ-TPA) film were achieved, which exhibits as camel gray (at −0.5 V), light gray (at 0 V) and army green (at 1.6 V). The maximum UV–vis absorption difference of poly(CBZ-TPA) film is about 15.83% in the visible region when applied with the voltage between 0 V and 1.6 V, and the coloring and bleaching time are 1.8 s and 1.0 s, respectively. The biggest different average IR-emissivity modulation of poly(CBZ-TPA) film is 0.37 in the wavelength regions of 8–14 μm. The copolymerization film of thiophene with CBZ-TPA has a distinct effect on the electrochromic performance of poly(CBZ-TPA) film. Compared with poly(CBZ-TPA) film, poly(CBZ-TPA-Th) film shows different colors, which exhibits as maize-yellow (at −0.5 V), milk white (at 0 V) and dark green (at 1.4 V). The maximum UV–vis absorption difference of poly(CBZ-TPA-Th) film is about 23.30% in the visible region between 0 V and 1.4 V, but it has a slower response speed (coloring and bleaching time are 3.0 s and 4.0 s, respectively). However, the biggest different average IR-emissivity modulation of poly(CBZ-TPA-Th) film reaches up to 0.41 in the wavelength regions of 8–14 μm compared to that of poly(CBZ-TPA) film. [ABSTRACT FROM AUTHOR]

A new method for nondestructive testing of coatings on exterior and interior surfaces of metal shells is proposed that is based on video monitoring of the infrared radiation emitted from the shell excited by shortterm external heating. Computer processing of the measured nonstationary field of temperature distribution on the outer surface allows defects with lateral dimensions on the order of or greater than the shell thickness to be revealed on the inner (inaccessible to observation) surface. Geometric characteristics of these defects can be evaluated. [ABSTRACT FROM AUTHOR]

The paper discusses a potential approach of infrared (IR)-analysis for high heat flux quality assessment of divertor tungsten monoblock components. The aim of these activities is the development of a statistics based method for the general application to the high heat flux testing of industrially manufactured W monoblock plasma-facing components. We have performed tests with 100 cycles at 10 MW/m 2 on 13 components or mock-ups manufactured for ITER, for the DEMO divertor development and for the WEST project. For eight W monoblock components with grinded surfaces, the statistical high heat flux (HHF) quality assessment method originally developed for the series manufacturing of carbon fibre reinforced carbon flat tile divertor components for Wendelstein 7-X was applied. The large variability of the emissivity of W as well as the monoblock geometry require a careful emissivity correction of IR camera data. The emissivity is strongly dependent on the W surface quality and final machining and influences the apparent temperature measured by an IR camera. Therefore we have applied a pragmatic correction algorithm based on two-colour pyrometry. Finally we propose a possible HHF testing strategy of a large number of industrially manufactured W monoblock components. [ABSTRACT FROM AUTHOR]

Flash infrared thermography (IRT) is a non-contact optical non-destructive technique, which has a promising application in the on-line inspection of disbonds in insulator of solid rocket motors (SRMs). In order to promote the application of IRT in the disbond inspection of insulators in SRMs, the basic regularities of pulsed thermography (PT) of disbonds in the insulator of SRM cases are studied by using numerical simulation and experiment. The relationships between decision-making parameters and structure parameters are obtained, the criterion to determine detection limits is proposed, the detection limits of disbond size and depth (i.e. insulator thickness) are calculated, and the method to characterize the disbond size and the error correction formula are provided. The equations, data and conclusions provide a scientific basis and operational guidelines for the infrared thermography of disbonds in insulator of SRMs. [ABSTRACT FROM AUTHOR]

Segregation is a serious challenge for high quality constructions of asphalt pavements. Temperature segregation (or temperature differential) in uncompacted asphalt mats has been identified with the use of infrared thermal cameras at the paving site. Four Louisiana asphalt rehabilitation projects were selected for investigating the effects of temperature segregation on the quality and performance of asphalt pavements. A multi-sensor infrared temperature scanning bar (IR-bar) system mounted behind the paver measured the real-time thermal profile. The quality of paving mats was measured by the density of field cores while the performance was measured by the mix-s intermediate temperature fracture resistance using the semi-circular bend (SCB) test. Results showed that temperature-segregated samples generally had lower densities than the control samples, although the differences were mostly statistically insignificant. On the other hand, temperature segregated samples generally had lower fracture resistance than the control samples measured by the SCB Jc values. Four out of six comparison cases showed the differences were statistically significant. Further verification effort was recommended for confident implementation of the IR thermal imaging technology to the asphalt pavement construction specification. [ABSTRACT FROM AUTHOR]

Northern Chilean Patagonia has numerous pristine lakes associated with perennial native forests. The present study looks at optical properties in visible, close, and medium infrared wavelengths in mountain lakes of Alerce Andino National Park (41°S). These lakes have associated Nothofagus and Fitzroya cupressoides native forests of glacial origins. The results revealed high reflectance values for B1 and B3 for Chaiquenes, Triangulo, and Sargazo lakes located within Nothofagus and F. cupressoides native forest; Precipicio Lagoon has high B3, B4, B5, B6, and B7 reflectance values, perhaps due to granite surroundings; and the remaining 18 lagoons have relative low reflectance values for all bands, probably due to the predominance of Cupressaceae forest and mountains that make access difficult. These differences are associated with surrounding vegetation and geological characteristics of the studied sites. [ABSTRACT FROM AUTHOR]

The food industry is one of the industries that uses machine vision for a nondestructive quality evaluation of the produce. These quality measuring systems and softwares are precalculated on the basis of various image-processing algorithms which generally use a particular type of classifier. These classifiers play a vital role in making the algorithms so intelligent that it can contribute its best while performing the said quality evaluations by translating the human perception into machine vision and hence machine learning. The crop of interest is rice, and the color of this crop indicates the health status of the plant. An enormous number of classifiers are available to solve the purpose of color prediction, but choosing the best among them is the focus of this paper. Performance of a total of 60 classifiers has been analyzed from the application point of view, and the results have been discussed. The motivation comes from the idea of providing a set of classifiers with excellent performance and implementing them on a single algorithm for the improvement of machine vision learning and, hence, associated applications. [ABSTRACT FROM AUTHOR]

The problem of simultaneous visual and thermal testing of microobjects is considered. For this purpose, a mirror-lens optical system is proposed and constructed. The system has no movable elements and provides identical scales of images in spectral ranges of 0.4-0.8 and 8-14 μm. The technique for calculating its dimensions and an experimental setup on the basis of this scheme are described. The results of its testing using an example of investigating microelectronic devices are presented. [ABSTRACT FROM AUTHOR]

Among various widely used InfraRed Thermal Non-Destructive Testing (IRTNDT) modalities, Non-Stationary Thermal Wave Imaging (NSTWI) techniques have proved to be an indispensable approach for the inspection and evaluation of various materials. Growing concern for the development of surface and subsurface defect detection techniques with moderate peak power heat sources (than the widely used conventional pulse based thermographic methods) and in a reasonably less testing time (compared to sinusoidal modulated lock-in thermography), makes these NSTWI techniques invaluable for this field. The present work highlights a comparative study on various NSTWI techniques, further experimental results are presented to find their defect detection capabilities by taking signal to noise ratio (SNR) into consideration. [ABSTRACT FROM AUTHOR]

Thermoelastic stress analysis (TSA) and digital image correlation (DIC) are used to examine the stress and strain distributions around the geometric discontinuity in a composite double butt strap joint. A well-known major limitation in conducting analysis using TSA is that it provides a metric that is only related to the sum of the principal stresses and cannot provide the component stresses/strains. The stress metric is related to the thermoelastic response by a combination of material properties known as the thermoelastic constant (coefficient of thermal expansion divided by density and specific heat). The thermoelastic constant is usually obtained by a calibration process. For calibration purposes when using orthotropic materials, it is necessary to obtain the thermoelastic constant in the principal material directions, as the principal stress directions for a general structure are unknown. Often, it is assumed that the principal stress directions are coincident with the principal material directions. Clearly, this assumption is not valid in complex stress systems, and therefore, a means of obtaining the thermoelastic constants in the principal stress directions is required. Such a region is that in the neighbourhood of the discontinuities in a bonded lap joint. A methodology is presented that employs a point-wise manipulation of the thermoelastic constants from the material directions to the principal stress directions using full-field DIC strain data obtained from the neighbourhood of the discontinuity. A comparison of stress metrics generated from the TSA and DIC data is conducted to provide an independent experimental validation of the two-dimensional DIC analysis. The accuracy of a two-dimensional plane strain finite element model representing the joint is assessed against the two experimental data sets. Excellent agreement is found between the experimental and numerical results in the adhesive layer; the adhesive is the only component of the joint where the material properties were not obtained experimentally. The reason for the discrepancy is discussed in the paper. [ABSTRACT FROM AUTHOR]

This paper deals with the determination of thermal stresses in nonhomogeneous prismatic bars by the application of theorem of minimum of complementary energy. The material properties and the applied thermal field do not depend on the axial coordinate. The presented analysis is valid for compound bars and bars made from functionally graded materials. The applied mechanical loads are bending moment and axial force at the end cross sections of the nonhomogeneous bar. An example illustrates the application of the presented formula to determine the normal stress field. [ABSTRACT FROM AUTHOR]

Carbon-fibre epoxy panels have been subjected to rapid high temperature loads. The effects of temperature, exposure time and moisture content of the panels have been studied. It could be demonstrated that the combination of high moisture content and rapid heating can lead to excessive damage, such as sudden formation of delaminations up to the development of large bubbles on the panel. While it is well known that matrix and fibre–matrix interface strength generally decrease both with water uptake and temperature increase, a more severe damage mechanism has been observed here. The combination of high moisture content and rapid high temperature loads leads to an internal vapour pressure overload that can cause extensive cracks and delaminations. Subsequently, this permanent damage leads to serious changes in mechanical properties. Whereas heating dry panels to 350℃ for 1 h and testing them at room temperature reduced interlaminar shear strength less than 25%, many of the moist panels were fully destroyed within the first minute of heating. [ABSTRACT FROM PUBLISHER]

After Swift, there is no sure plan to furnish a replacement for the rapidly disseminated, highprecision GRB positions it provides, nor a new type of observatory to probe new GRB parameter space.We propose a new GRB mission concept, the Next Generation Rapid Optical-NIR (near infrared) Response GRB Observatory (NGRG) concept, and demonstrate, through analysis of Swift BAT data, studies of new GRB samples, and extinction predictions, that a relatively modest size observatory will produce valuable new measurements and good GRB detection rates. As with Swift, GRBs are initially located with a coded-mask X-ray camera. However, the NGRG has two distinguishing features: first, a beam-steering system to begin optical observations within ~1 s after location; second, in addition to the optical camera, a separate near-IR (NIR) camera viewing the same field, greatly increasing sensitivity to extinguished bursts. These features yield the unique capability of exploring the rise phase of GRB optical-NIR emission. Thus far, among GRBs with optical afterglow detections, a peak is measured in only ~26-40% of the light curves. The rise time for prompt, or pre-afterglow, optical emission is rarely measured, as is the transition to afterglow emission. Prompt or pre-afterglow NIR emission is even less frequently measured. Rapidresponse measurements give new tools for exploration of many science topics, including optical emission mechanisms (synchrotron vs. SSC, photospheric emission) and jet characteristics (reverse vs. forward shock emission, baryon-dominated vs. magnetic dominated). The rapid-response capability also allows measurement of dynamic evolution of extinction due to vaporization of progenitor system dust. This dynamic dust measurement is the only tool we know of to separate the effects of star-system-scale dust and galactic-structure-scale dust; it is remarkable that this probe of small-scale phenomena can be used at the high redshifts where GRBs are observed. In this paper, we discuss techniques and the feasibility of these measurements, and give detection rate estimates using only measured Swift performance (without extrapolations). The NGRG will explore two new frontiers: optical and NIR GRB emission measured earlier than ever before, via rapid-response, and potentially fainter, more extinguished GRBs than ever before, via sensitive, early NIR measurements. In an era with little funding for new extragalactic science space missions, costs are important. Our modest NGRG concept will produce new GRB science, while providing crucial access to rapid GRB alerts for the community. An X-ray instrument barely 1/5 the detecting area of Swift BAT, 1024 cm², will yield a significant fraction of BAT's GRB detection rate: more than 65 X-ray detections per year. With a 30 cm optical-IR telescope and modern cameras, more than 19 NIR and 14 optical band detections would be produced each year for community follow-up. In addition, active control of the beam-steering system, via feedback from a fast-read optical camera, would remove the need for arcsec pointing stabilization of the spacecraft platform, for a substantial cost saving and a wider range of potential space platforms. [ABSTRACT FROM AUTHOR]

Mechanical joints such as bolted or pinned connections are commonly used to fasten mechanical or structural members together. Inadequate knowledge of the stresses at the edge of the loaded holes can render it difficult to stress analyze such mechanical fasteners theoretically or numerically. Thermoelastic stress analysis (TSA) is utilized here to analyze a plane-stressed pin-loaded plate. The approach combines the recorded temperature information with an Airy stress function, plus imposes the traction-free conditions on the non-contacting edge of the hole and on the external boundaries of the plate. Individual components of stress are determined full-field as well as on the pin-plate interface. In addition to agreeing with the frequently assumed interface contact stresses in mechanical connections having zero clearance, the TSA results satisfy force equilibrium, are compatible with residual markings on the contacted surfaces of the pin and the hole, and correlate with FEM predictions. Significant advantages of TSA here include neither needing to know the elastic modulus nor to differentiate the recorded information. [ABSTRACT FROM AUTHOR]

Using lattice simulations, we study the infrared behavior of a particularly interesting SU(2) gauge theory, with six massless Dirac fermions in the fundamental representation. We compute the running gauge coupling derived nonperturbatively from the Schrödinger functional of the theory, finding no evidence for an infrared fixed point up through gauge couplings g-2 of order 20. This implies that the theory either is governed in the infrared by a fixed point of considerable strength, unseen so far in nonsupersymmetric gauge theories, or breaks its global chiral symmetries producing a large number of composite Nambu-Goldstone bosons relative to the number of underlying degrees of freedom. Thus either of these phases exhibits novel behavior. [ABSTRACT FROM AUTHOR]

Highlights: [•] A Global Signal to Noise Ratio that comprehensively evaluates defect detectability. [•] An Infrared Image Quality Index that compares visual structural information in infrared images. [•] This global approach determines the time at which the majority of the defects become visible. [ABSTRACT FROM AUTHOR]

Highlights: [•] We proposed a method for reducing the impact of emissivity unevenness and heating non-uniformity. [•] The method using the self reference technology is based on the source distribution image. [•] Three thermograms captured right after heat pulse are averaged to create SDI. [•] For the missing bump the summation of thermal difference is no more than 14K. [•] It is effective using the method to identify the defects in active infrared test. [ABSTRACT FROM AUTHOR]

The propagation of waves in micropolar thermoelastic homogeneous plate with two temperatures subjected to stress free thermally insulated and isothermal conditions is investigated. The secular equations for both symmetric and skew-symmetric wave mode of propagation have been derived. Helmholtz decomposition technique has been used to simplify mathematical model and frequency equations for different mechanical conditions. The regions of secular equations are obtained and some special cases such as thin plate and short wavelength waves of the secular equations are also discussed. The phase velocity and attenuation coefficient are computed numerically and depicted graphically. The amplitudes of stress components and thermodynamic temperature distribution for the symmetric and skew-symmetric wave modes are computed analytically and presented graphically. Results of some earlier workers have been deduced as particular cases. [ABSTRACT FROM AUTHOR]

Utilizing the synergy of the capabilities of CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations ( CALIPSO) and ~4.5 years of their observations, this paper investigates the dependence of the altitude distribution and thickness of tropical clouds on sea surface temperature (SST). Variations in the altitude distribution of clouds with SST show three distinct regimes: SST < 27.5°C, 27.5° < SST < 29°C, and SST > 29°C. At an SST < 27.5°C, the convection is rather weak, so that most of the clouds are limited to <2-km altitude with peak occurrence at 1-1.5 km. The frequency of occurrence of the low-altitude clouds as well as the prominence of the peak at ~1.5 km consistently decreases for SST > 24°C. Vertical development of clouds through the 3-12-km-altitude region increases for SST > 27.5°C to achieve maximum cloud occurrence and thickness in the SST range of 29°-30.5°C. Penetration of the deep convective clouds to altitudes >15 km and their frequency of occurrence increase with SST until ~30°C. These observations reveal two differences with the SST dependence of total cloudiness observed using passive imager data: (i) the increase in cloudiness at an SST > 26°-27°C observed using the imager data is found to be influenced by the increase in cirrus clouds generated by deep convective outflows and is not directly driven by the local SST, and (ii) the total cloudiness does not decrease for SST > 29.5°C as observed using imagers, but weakly increases until an SST of ~30.5°C. The role of the spatial gradient of SST and atmospheric dynamical parameters in modulating the observed SST dependence of cloudiness at different SST regimes is investigated. [ABSTRACT FROM AUTHOR]

The determination of defect depth and size using Pulsed Infrared Thermography is a critical problem. The problem of defect depth estimation has been previously studied using 1D heat conduction models. Unfortunately, 1D heat conduction based models are generally inadequate in predicting heat flow around defects. In this study, a novel approach based on virtual heat sources is proposed to model heat flow around defects accounting for 2D axisymmetric heat conduction. The proposed approach is used to quantitatively determine the defect depth and size. The validity of the model is established using experiments performed on a stainless steel plate specimen with flat bottom holes at different depths. [ABSTRACT FROM AUTHOR]

A series of sonic IR tests were performed on modified eccentrically-loaded single edge tension [ESE(T)] specimens in which crack lengths were nominally identical, but the precracking load history used to develop the sharp cracks used in the tests was varied from specimen to specimen. A measure for crack engagement length, defined as the length of crack that develops heat during sonic IR inspection was established for these tests. The result suggest that, in a certain regime, crack engagement length correlates with fatigue opening load, which is the stress intensity factor at which the crack front is fully open during the fatigue precracking. The implication of this is that laboratory test results for sonic IR should be performed with test specimens that have undergone careful precracking procedures, and that these procedures should be reported with test results. [ABSTRACT FROM AUTHOR]

Combining thermal imaging techniques measurements tension and Thermal imaging analysis gives a general picture of the distribution of tension. In this work presented visual and virtual instrumentation based on infrared analysis of thermoelastic stress. A simple test The parts of the construction where the highest tension occur are determined by the thermal analysis. The TSA also helps to make a faster and in a predictable manner, without need for extensive iterative investigations, what reduces both time and costs. [ABSTRACT FROM AUTHOR]

The article explores the discovery and characterization of super soft kernel texture trait in wheat. The study indicates the minimal impact of near-infrared (NIR) hardness and that it is associated to the yield of superior break flour in milling. It stresses the potential contribution of NIR hardness in enhancing the quality of the cake. It also notes the opportunities provided by the trait with the wheat breeders in the modification of end-use wheat quality.

We describe the design, integration, and operation of the infrared test cameras for the commissioning of the Large Binocular Telescope. The design and construction phase lasted slightly more than one year from February 2007 to April 2008 and was the result of a joint collaboration among INAF Osservatorio Astronomico di Bologna, Università di Bologna Dipartimento di Astronomia (Italy) and the Max-Planck-Institut für Astronomie (Heidelberg, Germany). Thereafter, the camera was delivered to the LBT Observatory (USA) for commissioning of the telescope active optics and, more recently, for commissioning of the first light adaptive optics. [ABSTRACT FROM AUTHOR]

This paper proposes a Barker coded excitation for defect detection using infrared non-destructive testing. Capability of the proposed excitation scheme is highlighted with recently introduced correlation based post processing approach and compared with the existing phase based analysis by taking the signal to noise ratio into consideration. Applicability of the proposed scheme has been experimentally validated on a carbon fiber reinforced plastic specimen containing flat bottom holes located at different depths. [ABSTRACT FROM AUTHOR]

The infrared thermography has been applied in the past to investigate the high cycle fatigue and to predict the fatigue endurance limit of metals and welded joints. The aim of the present study was to investigate the low cycle fatigue process using an infrared scanner. Experimental tests have been carried out to analyse the low cycle fatigue process of three types of ASTM A 516 gr. 70 steels. The thermal increments during the fatigue life were correlated with the hysteresis loops derived from the traditional procedure. It was demonstrated that an asymptotic temperature increment corresponds to a stable hysteresis loop. [ABSTRACT FROM AUTHOR]

In analog holography, the infrared (IR) range received quite some attention, since it could provide interesting information, not achievable otherwise. Since digital sensors in this band became recently available and affordable, also digital holography (DH) expanded its feasibility beyond the visible wavelengths. In fact, the IR range allows shorter recording distances, unparalleled larger field of view and less stringent requirements on system stability, together with some specific characteristics, like e.g. the possibility to test IR glasses or other materials transparent to IR radiation, which cannot be controlled in visible range. In this paper we review the activities which took place in this field and illustrate the results achieved, referring to the opportunities this technique offers, and the challenges it presents. We show efficient reconstructions of holograms of objects of various materials, recorded with different resolution digital thermal cameras, in various configurations, and moreover we demonstrate optical holographic display through a liquid crystal based Spatial Light Modulator which gives the chance to get direct 3D imaging and display of long IR range. Moreover we believe this opens the route toward holography in THz region. [ABSTRACT FROM AUTHOR]

The article focuses on study of the development of infrared-microwave rainfall algorithm (IMRA) to retrieve spatial rainfall from infrared (IR) brightness temperatures (TBs) of satellite sensors. IMRA was made to discriminate rain/no-rain pixels through IR image cloud-top temperature gradient. The result of the study indicates that the SLOPE technique (ST) option of IMRA gave precise satellite rainfall estimate for both light and heavy rainfall systems.