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A wide range of behaviors, including non-monotonic rejuvenation and relaxation, and the ability to qualitatively change the effect by varying the structural state of the glass was observed during thermal cycling of bulk metallic glasses. For this, we considered various bulk metallic glasses, Zr44Ti11Cu10Ni10Be25, Pd43Cu27Ni10P20, Pt57.5Cu14.7Ni5.3P22.5, and La55Al25Ni20, at various fictive temperatures to study the effect of thermal cycling on structure, thermal signature, and fracture toughness. For some BMGs and conditions considered here, thermal cycling results in a looser structure and an increase in fracture toughness. We found that for certain other BMGs and conditions, thermal cycling results in relaxation, reflected in a denser structure, and a decrease in fracture toughness. All these responses are non-monotonic and reveal a pronounced extremum with fracture toughness values of ± 50% of the original value, before approaching a value similar to the original value prior to thermal cycling. Such richness in response to thermal cycling suggests incompleteness of the previous picture where monotonically decreasing local stresses resulting in a homogenization of the structure with increasing cycle number. Our finding suggests that relative comparisons of various contributions including activation barriers for α-relaxation have to be considered which are also constantly changing, to decide if further cycling results in an increase or a decrease in fracture toughness. The fracture toughness’ response to thermal cycling can be correlated with the average atomic structures’ response to thermal cycling, while the thermal response does not exhibit an obvious correlation.

For sustainable growth of road networks in a country, their effective maintenance is an essential element of pavement evaluation and management strategies. Destructive testing practices are slow, labor-intensive and do not represent the entire pavement area. Advances in non-destructive testing technologies offer a convenient and reliable means of quickly scanning large areas. Infrared thermography based on capturing the thermal signature of any structure is found to be very useful for detecting pavement subsurface flaws. This study aims at exploring the potential of infrared thermography to detect subsurface interlayer debonding in asphalt pavements. An in-situ asphalt pavement test section has been constructed with different bonding conditions, and infrared thermography has been performed. A novel approach for quantitative and qualitative analyses of these thermal images has been carried out using MATLAB. Suitable time durations to perform thermographic inspections based on interchange time duration have been suggested.

The average density of 3300 kg m−3 is often attributed for the asthenosphere. In this study, we inspect this value by estimating the average value of the (upper) asthenosphere based on applying the gravimetric forward modelling of major known lithospheric density structures. The LITHO1.0 global seismic model of the lithospheric density structure is used for this purpose, while considering that the lithosphere-asthenosphere boundary (LAB) is rheological, conventionally taken at the 1300 °C isotherm, above which the mantle behaves in a rigid fashion and below which it behaves in a ductile fashion. According to our result, the average density of the upper asthenosphere is roughly 3400 kg m−3. This density value closely agrees with the corresponding average value 3371 kg m−3 computed based on an empirical density model provided in the Preliminary Reference Earth Model (PREM), while using the LITHO1.0 LAB depth data. We also demonstrate that the sub-lithospheric mantle gravity map exhibits mainly a thermal signature. The most prominent features in this gravity map are mid-oceanic spearing ridges marked by gravity lows, while oceanic subductions in the West Pacific are characterized by the most pronounced gravity highs. Keywords: Asthenosphere, Density, Forward modelling, Gravity, Lithosphere

The experimental results from infrared thermography surveys over two buildings externally exposed walls are presented. Data acquisition was performed on a static configuration by recording direct and indirect solar loading during several days and was processed using advanced signal processing techniques in order to increase signal-to-noise ratio and signature contrast of the elements of interest. It is demonstrated that it is possible to detect the thermal signature of large internal structures as well as surface features under such thermographic scenarios. Results from a long-wave microbolometer compared favorably to those from a mid-wave cooled infrared camera for the detection of large subsurface features from unprocessed images. In both cases, however, advanced signal processing greatly improved contrast of the internal features.

The infrared detection technology has been widely explored in military domain for signature acquisition and search and tracking of targets. Thermal signatures of any targetare fingerprints for detection by Thermal Imaging System (TIS). Armoured vehicles and equipments are very prone for detection by adversary’s TIS. Multi-layered Textile Structures (MTS) have been designed and developed by efficient insulating materials for thermal signature suppression of ground based targets in 8–12 µm. These structures were evaluated by FLIR TIS in 7.7–11.5 µm at temperatures 50, 100, 150 °C and stand-off distances 8, 16, 24 mm from hot plate. The maximum thermal suppression efficiency of MTS04 and MTS06 are 91.25% and 96.25% respectively. The MTS04 is suitable for thermal suppression of targets upto100°C and MTS06 is more effectiveupto150°C. Spatial configuration of MTS04 and MTS06 as per thermal zones of the target can be arranged for design and development of effective thermal camouflage system for static and dynamic objects.

The prediction of lava flow advance and velocity is crucial during an effusive volcanic crisis. The effusion rate is a key control of lava dynamics, and proxies have been developed to estimate it in near real-time. The thermal proxy in predominant use links the satellite-measured thermal radiated power to the effusion rate. It lacks however a robust physical basis to allow time-dependent modeling. We investigate here through analogue experiments the coupling between the spreading of a solidifying flow and its surface thermal signal. We extract a first order behavior from experimental results obtained using polyethylene glycol (PEG) wax, that solidifies abruptly during cooling. We find that the flow advance is discontinuous, with relatively low supply rates yielding long stagnation phases and compound flows. Flows with higher supply rates are less sensitive to solidification and display a spreading behavior closer to that of purely viscous currents. The total power radiated from the upper surface also grows by stages, but the signal radiated by the hottest and liquid part of the flow reaches a quasi-steady state after some time. This plateau value scales around half of the theoretical prediction of a model developed previously for the spreading and cooling of isoviscous gravity currents. The corrected scaling yields satisfying estimates of the effusion rate from the total radiated power measured on a range of basaltic lava flows. We conclude that a gross estimate of the supply rate of solidifying flows can be retrieved from thermal remote-sensing, but the predictions of lava advance as a function of effusion rate appears a more difficult task due to chaotic emplacement of solidifying flows.

A recent study by Schmidt et al. (2011) suggests that Thera Macula, one of the “chaos regions” on Europa, may be actively forming over a large liquid water lens. Such a process could conceivably produce a thermal anomaly detectable by a future Europa orbiter or flyby mission, allowing for a direct verification of this finding. Here, we present a set of models that quantitatively assess the surface and subsurface temperatures associated with an actively resurfacing chaos region using constraints from Thera Macula. The results of this numerical study suggest that the surface temperature over an active chaos region can be as high as ∼ 200 K . However, low-resolution Galileo Photo-Polarimeter Radiometer (PPR) observations indicate temperatures below 120 K over Thera Macula. This suggests that Thera Macula is not currently active unless an insulating layer of at least a few centimeters in thickness is present, or activity is confined to small regions, reducing the overall intensity of the thermal signature. Alternatively, Thera may have been cooling for at least 10–100 yr and still contain a subsurface lake, which can take ∼300,000 yr to crystallize. According to the present study, a more sensitive instrument capable of detecting anomalies ∼5 K above ambient could detect activity at Thera Macula even if an insulating layer of ∼50 cm is present.

The thermal signature of an equilibrium liquid–liquid transition (LLT) in triphenyl phosphite was detected by differential scanning calorimetry measurements at a fast heating rate reaching 500 K min −1 . The estimated temperature, enthalpy, and entropy of the LLT were 241.7 K, 12.0 kJ mol −1 , and 49.5 J K −1 mol −1 , respectively. The estimated residual entropy for a glacial sample prepared at 224.7 K was 6 J K −1 mol −1 ; this value is much smaller than that for the normal glassy liquid. This glacial state was found to be a highly ordered liquid compared with the normal glassy liquid in terms of entropy.

Linear features dubbed “tiger stripes” in the south polar region of Enceladus have anomalously high heat fluxes and are the apparent source of the observed plume. Several explanations for the observed activity have been proposed, including venting from a subsurface reservoir of liquid water, sublimation of surface ice, dissociation of clathrates, and shear heating. Thermal modeling presented in this work, coupled with observations from the Cassini Composite Infrared Spectrometer (CIRS) instrument, seeks to elucidate the underlying physical mechanism by constraining vent temperatures and thermal emission sources, using a model in which the observed thermal signature results primarily from conductive heating of the surface by warm subsurface fractures. The fractures feed surface vents, which may themselves contribute to the observed thermal emission. Model variables include vent temperature, presence of a surface insulating layer, vent width, time-variable heat input, and heat sources other than the central vent. Results indicate

A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either “push” or “pull”, one novel synthetic jet actuator can fulfill both “push” and “pull” functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various applications, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.

The attention of the present paper was devoted to nondestructive evaluation of masonry structures with a Focal Plane Array infrared camera. Tests were carried out in laboratory on specimens, which simulated one- and two-layer structures, with defects of different geometry and nature and located at different depths. The defects detection was analysed through a cause/effect relationship between the characteristics of defects and hosting material and the observed defect thermal signature, or contrast, on the hosting material.

A model of thermal phenomenon in soil developed to determine its thermal signatures in case of buried land mines in presented in the paper. Thermal signature values of a mine buried in two types of soil having different properties were compared using mathematical–statistical modelling. Results generated by modelling have been verified by laboratory experiment. � 2002 Published by Elsevier Science B.V.

Periods of elevated temperatures in northern Monterey Bay suggest that this is a region of increased residence time during periods of active upwelling. Nearshore increases in near-surface temperature often coincide with offshore decreases in temperature as cold, upwelled water is advected into the center of the bay—the juxtaposition of warm and cold water enhancing the thermal signature of a feature described as an ‘upwelling shadow’. We present a variety of data collected from 1988 to 1993 invoking a shallow, stratified, cyclonic circulation in northern Monterey Bay to explain the upwelling shadow as a dynamic response to upwelling north of the bay. Residence times associated with this warm recirculation are of the order of 8 days which is comparable to semi-enclosed embayments whereas Monterey Bay is an open embayment. We estimate a continuous replacement of upwelling shadow water with offshore water at a rate of 0.083 day −1 , and we suggest that a circulation velocity of 0.1 m · s −1 , is needed to produce the thermal signature of the feature given published values of surface heat flux in the central California coastal region. The thermal signature of this upwelling shadow persists through much of the upwelling season, surviving brief relaxations in upwelling but breaking down during prolonged relaxations of the order of a week or longer. The stratification and coherent recirculation of this feature is likely to be very important for such biological processes as productivity and the dispersal and recruitment of larvae.

Surface ship-of-opportunity and satellite remotely sensed sea-surface temperature (SST) data were obtained during the mature phase of the Southwest Monsoon in the north-western Indian Ocean for the years 1976–1979. Large wedge-like areas of upwelled water are observed at 5°N and 10°N after Somali Current spinup, indicative of a two-gyre circulation in the Somali Current system. Several months later the southern separation region is observed to translate poleward (5–75 cm/s) in three of the four years. This translation occurs in several distinct phases over a one-month interval with the southern wedge eventually coalescing with the northern wedge between 8 and 10°N (1976, 1979). (In 1978 the northern wedge translated past Socotra and dissipated in the Arabian Sea). The thermal signature of the “new” northern wedge becomes indistinct over a period of two to three months later.