Understanding thermal and rheological behaviors of bimodal polymethyl methacrylate (BPMMA) fabricated via solution blending

In this work, a series of bimodal polymethyl methacrylate (BPMMA) was fabricated via solution-blending two neat PMMA resins. Rheology, DMTA, thermal infrared imager measurements were used in an attempt to probe the internal structure of the as-prepared BPMMA. It was demonstrated that the thermorheological behavior of the BPMMA was heavily dependent on shear rate, temperature as well as blending ratio. In addition, a typical “V-shaped” response, namely, a dip in storage modulus (G′) followed by an upturn in the plot of G′ versus measuring temperature for D4 (with lower weight-average molecular weight) was observed, characteristic of occurrence of thermorheological complexity. Our experimental results of physical–mechanical testings suggested that the BPMMA had better comprehensive properties than those of their neat PMMA counterparts.

Geometric correction for thermographic images of asteroid 162173 Ryugu by TIR (thermal infrared imager) onboard Hayabusa2

The thermal infrared imager (TIR) onboard the Hayabusa2 spacecraft performed thermographic observations of the asteroid 162173 Ryugu (1999 JU$$_3$$ 3 ) from June 2018 to November 2019. Our previous reports revealed that the surface of Ryugu was globally filled with porous materials and had high surface roughness. These results were derived from making the observed temperature maps of TIR using a projection method onto the shape model of Ryugu as geometric corrections. The pointing directions of TIR were calculated using an interpolation of data from the SPICE kernels (NASA/NAIF) during the periods when the optical navigation camera (ONC) and the light detection and ranging (LIDAR) observations were performed. However, the mapping accuracy of the observed TIR images was degraded when the ONC and LIDAR were not performed with TIR. Also, the orbital and attitudinal fluctuations of Hayabusa2 increased the error of the temperature maps. In this paper, to solve the temperature image mapping problems, we improved the correction method by fitting all of the observed TIR images with the surface coordinate addressed on the high-definition shape model of Ryugu (SFM 800k v20180804). This correction adjusted the pointing direction of TIR by rotating the TIR frame relative to the Hayabusa2 frame using a least squares fit. As a result, the temperature maps spatially spreading areas were converged within high-resolved $$0.5^\circ$$ 0 . 5 ∘ by $$0.5^\circ$$ 0 . 5 ∘ maps. The estimated thermal inertia, for instance, was approximately 300$$\sim$$ ∼ 350 Jm$$^{-2}$$ - 2 s$$^{-0.5}$$ - 0.5 K$$^{-1}$$ - 1 at the hot area of the Ejima Saxum. This estimation was succeeded in case that the surface topographic features were larger than the pixel scale of TIR. However, the thermal inertia estimation of smooth terrains, such as the Urashima crater, was difficult because of surface roughness effects, where roughness was probably much smaller than the pixel scale of TIR.

VELOX - A new thermal infrared imager for airborne remote sensing of cloud and surface properties

<p>The new airborne thermal infrared imager VELOX (Video airbornE Longwave Observations within siX channels) is introduced. It covers six spectral bands in the thermal infrared wavelength range from 7.7 μm to 12 μm and is operated on board of the German High Altitude and Long Range Research Aircraft (HALO) of the German Aerospace Center (Deutsches Luft und Raumfahrtzentrum, DLR). The imager measures two-dimensional (2D) fields of the upward terrestrial radiance within a field of view of 35.5° by 28.7° with 640 by 512 spatial pixels. These 2D radiance fields can be converted into 2D fields of brightness temperature. With a horizontal resolution of better than 10 m VELOX extends the HALO remote sensing instrument suite to observe clouds and surface properties. The calibration and correction procedures for VELOX are presented. First measurements, collected during the ElUcidating the RolE of Cloud-Circulation Coupling in ClimAte (EUREC<sup>4</sup>A) campaign are shown, including analysis of the cloud top brightness temperature, cloud mask/fraction calculations, cloud top altitude estimates, and Sea Surface Temperature (SST) analysis. The investigations reveal that the cloud top temperature can be resolved with a resolution of about 0.1 K, which translates into a vertical resolution of about 10 m with respect to cloud top altitude.</p>

Geometric Correction for Thermographic Images of Asteroid 162173 Ryugu by TIR (Thermal Infrared Imager) onboard Hayabusa2

The thermal infrared imager (TIR) onboard the Hayabusa2 spacecraft performed thermographic observations of the asteroid 162173 Ryugu (1999 JU3) from June 2018 to November 2019. Our previous reports showed the surface temperature and thermal inertia maps of Ryugu. At that time, the mapping procedure from observed TIR images to the shape model of Ryugu has been developed as a geometric correction method. The method used the shape model derived from the observed images by the optical. navigation camera (ONC), a numerical geometry toolkit, SPICE kernels (NASA/NAIF) based on the spacecraft attitude data derived from ONC images, and the measured altitudes by the light detection and ranging (LIDAR). The pointing directions of TIR were calculated using an interpolation of data from SPICE kernels during the periods when the ONC or LIDAR observation was performed. Still, the mapping accuracy of the observed TIR images was degraded when the ONC and LIDAR observations were not performed with TIR. In this paper, to solve the problem of the mapping procedure, we improved the correction method by matching the TIR images, which carried out a one-to-one correspondence between the observed points in the TIR images and the surface nodes addressed on the shape model of Ryugu. This geometric correction adjusted the pointing direction of TIR by rotating the TIR frame relative to the base of the Hayabusa2 frame using a least squares fit. The resulting temperature maps spatially spreading more than 10° were improved after the correction, and high-resolved 0.5° by 0.5° maps were constructed. The geometric correction was effective for characteristic regions where the terrain was comparable to the pixel scale of TIR, such as the Ejima Saxum. The estimated thermal inertia of the bottom of Ejima Saxum was approximately 300 Jm-2s-0.5K-1. Thus this estimation was succeeded in case that the surface topographic features were the pixel scale of TIR. However, the thermal inertia estimation of smooth terrains, such as the Urashima crater, was difficult because of surface roughness effects, where roughness was probably less than the pixel scale of TIR.

Correlation Between Ion Contents in Acupuncture Points and Propagated Sensation a long with Channel

Background: Propagated sensation along with channels are phenomena that occur because of stimulations during acupuncture therapies and tend to transmit the stimulating signals along the meridians. From the Western medicine aspect, researchers consider the phenomena as neurotransmissions initiated by nerves, and various ions regulate the physiological functions of the nervous systems.Objective: The object of this research is to investigate the key characteristics of ions at acupoints and the mechanism of propagated sensation along with channels, which are crossing meridians in traditional Chinese medicine (TCM).Methods: This research first conduct experiments by applying intense pulse light beams, which replace the traditional acupuncture treatments, on designated acupoints of studied human subjects, and employ a thermal infrared imager to monitor the temperature responses, which are induced by post sensation, in adjacent regions of the acupoints. Meanwhile, the research applies a synchrotron radiation technique on adult SD (Sprague Dawley) rats, and the study analyses the output responses with an X-ray Absorption Fine Spectroscopy (XAFS) to investigate the ion distributions in the relevant acupoints, which might trigger the propagated sensation crossing meridians.Results: Experimental results demonstrate that significant temperature increases simultaneously at the stimulated acupoints and certain other acupoints, whether in the same meridians. Moreover, XAFS experimental results indicate significantly high levels of calcium, potassium, and sulfide ions at the stimulated acupoint regions. On the contrary, the measured chloride ions level at the regions is correspondingly lower.Conclusions: The thermal infrared imager monitoring show significant temperature variations of crossing-meridian acupoints after implementing the intense pulse light beams on designated acupoints, and it implies the occurring of prolonged sensation along with channels using acupuncture therapies. The x-ray absorption spectrum demonstrates significant differences in ion amounts and distributions between the acupoints and non-acupoints, and acupuncture therapies result in ion concentrations in the correlated regions inducing propagated sensation crossing meridians in TCM. Hence, the stimulated acupoints operate as ion reservoirs to provide high-concentration of specific ions to trigger the crossing-meridian post sensation.

Indirect Measurement of Forest Canopy Temperature by Handheld Thermal Infrared Imager through Upward Observation

The influence of leaf temperature on transpiration, photosynthesis, respiration, and other metabolic activities is critical to plant growth, development, production and distribution. However, traditional measurement of canopy temperature by thermocouples or thermal infrared thermometers is laborious and difficult, especially for tall trees. The recent development of a handheld thermal infrared imager has made it possible to perform high temporal and spatial canopy temperature measurements efficiently. However, the signal recorded by the sensor is often a mixture of radiation from the target and the atmosphere, which must be corrected to get the true temperature. In this study, we propose a ground-based indirect measurement method of canopy temperature by a handheld thermal infrared imager through upward observation. Visible and thermal images are combined to distinguish the canopy pixels and sky pixels. To remove the atmospheric radiation from the sky, an empirical atmospheric model is established, which can perform atmospheric correction accurately and efficiently. To validate the proposed method, we collected canopy temperatures of 36 species of trees with a FLIR T420 thermal infrared imager and compared the estimated temperatures with those directly measured by thermocouples. The accuracy of the corrected canopy temperature has been significantly improved with mean absolute error reduced from 3.73 °C to 0.64 °C. This proposed canopy temperature measurement method can be used to various applications in remote sensing product validation, and ecosystem and forestry studies.

Bionic design for the heat sink inspired by phyllotactic pattern

A good heat dissipating condition will help give full play to the performance and reliability of electronic components and devices. To strengthen the heat dissipating performance, a novel bionic heat sink of pin fins has been designed. The configuration of cooling pin fins in this heat sink is based on phyllotaxis theory in biology. The bionic configuration of the cooling pin fins has better homogeneity and complementarity, which can form a reasonable air flow channel to improve its cooling efficiency. For testing and analyzing the performance of the bionic heat sink and the effects of the phyllotactic parameters on the heat dissipating, some contrast experiments have been conducted using thermal infrared imager. The results show that the bionic heat sink has better heat dissipating performance, which can make the surface temperature of the heat block lower by 14.7%. This paper will supply a new and effective solution to heat dissipation problem and has a certain contribution for the development of electrical and electronic industry.