Anomaly in the differential cross sections at 13 TeV

The analysis of the new TOTEM data at 13 TeV in a wide momentum transfer region reveals the unusual phenomenon — the presence in the elastic scattering amplitude of a term with a very large slope that is responsible for the behavior of hadron scattering at a very small momentum transfer. This term can be connected with hadron interactions at large distances.

Heat Transfer Enhancement in a Double Sequential Impingement Channel

Sequential impingement channels can reduce the adverse effect of crossflow in narrow impingement channels, as well as increase the cooling efficiency. In this work, sequential impingement channels are experimentally investigated using the transient liquid crystal technique to assess their thermal performances. A low heat transfer region is identified in the downstream part of the first channel where the flow is discharged into the second plenum. Various means of increasing the heat transfer at this location are investigated. Ribs on the target plate allow for an increase of the average heat transfer coefficient with small losses in pressure. Reducing the channel cross-section increases the mean flow velocity and, combined with the ribs, allows for a further increase of the heat transfer. Additionally, the geometrical changes of the channel caused by the addition of a ramp with a rounded corner, allow to decrease the pressure losses associated with the discharge into the second plenum, which is not optimal in the baseline configuration due to the sharp corner of the purge hole. Further reducing the cross-section to increase the heat transfer, however, increases the pressure losses due to the small open area in the transition zone.

Heat Transfer and Flow Characteristics of the Jet Array Impingement

An experimental and numerical study is performed to investigate heat transfer and pressure loss characteristics for impingement. Experimental heat transfer is measured by the thermochromic liquid crystal. The CFD model uses a steady state RANS approach and the shear stress transport (SST). The effect of Reynolds number (5000–25000), the distance between the holes and the distance from the hole to target on the impingement is investigated in the present study. Local Nusselt number as well as area and line average values are gotten experimentally and numerically. Besides, numerical simulations provide the detailed flow characteristics of the problem and complement experimental measurements. The result shows that the heat transfer increases with Reynolds number increasing. But the qualitative distribution of local heat transfer does not change with the increase of Reynolds number, when it is sensitive to P/D and Z/D. The performance of heat transfer is best when Z/D = 2. And the high heat transfer region of Z/D = 1 is closer to the exit than that of Z/D = 2 and Z/D = 3. The main reason is the effect of cross flow and the momentum of the jet reaching the wall. The performance of heat transfer is best when P/D = 5. And the high heat transfer region of P/D = 4 is closer to the exit than that of P/D = 5 and P/D = 6. The main reason is the effect of cross flow and interactions between jets.

Supramolecular Chirogenesis Engineered by Pt(II)···Pt(II) Metal-Metal Interactions

Supramolecular chirogenesis represents an effective way to induce chirality at the supramolecular level. For the previous host-guest chirogenic systems, metal–ligand coordination, hydrogen bonding, π-π stacking and hydrophobic interactions have been mainly employed as the non-covalent driving forces. In this study, Pt(II)···Pt(II) metal-metal interactions have been engineered to induce supramolecular chirogenesis, by forming non-covalent clipping structures between chiral platinum receptors and achiral platinum guests together. It results in the emergence of Cotton effects in the metal-metal-to-ligand charge transfer region, ascribed to chirality transfer from trans-1,2-diamide cyclohexane unit on chiral receptors to Pt(II)---Pt(II) non-covalent interacting sites. Supramolecular chirogenesis can be further transferred from organic to aqueous solutions, with higher resistance to concentration and temperature variations in the latter medium. Overall, the current study provides new avenues toward supramolecular chirality systems with tailored properties.

Experimental Study on Heat Transfer of Leading Edge Film-Cooling With Counter-Inclined Cylindrical and Laid-Back Holes

The heat transfer coefficient of counterinclined film holes fed by different intake structures on the turbine vane leading edge (LE) model is experimentally investigated in this paper. A semicylinder model is adopted to model the vane leading edge, which is arranged with one single row of film holes per side, which are located from the stagnation at a 15-deg angle. The four leading edge models, which are the combinations of the hole-shapes (cylindrical hole and laid-back hole) and intake structures (plenum and impingement), are tested at four blowing ratios M. The contours of the heat transfer coefficient, which are characterized by the Frössling number Fr, since it includes the Reynold number effect, are acquired by the transient measurement technique based on double thermochromic liquid-crystals (LCs). The lateral-averaged Fr of the nonfilm-cooled model is provided by using the same experimental platform with an identical main-flow condition. It is then compared with the published data, which indicates the reliability of the present transient measurement techniques. The results illustrate that a core region with a higher heat transfer appears in the hole-exit downstream, and its distribution is slightly skewed to the inclination direction of the film holes. The shape of the high heat transfer region gradually inclines in the spanwise direction as M increases. The heat transfer in the region where the jet core flows through is relatively low, while the jet edge region is relatively high. The effect of impingement leads to the outflow of each hole becoming increasingly uniform, which can reduce the difference in the heat transfer between the region where the jet core flows through and the jet edge. The heat transfer strength may increase due to the intense turbulence caused by the introduction of the impingement. Compared with the cylindrical hole, the laid-back hole has a spanwise expansion feature, which makes the shape of the high heat transfer region wider in the spanwise direction and increases the heat transfer level. Additionally, the magnitude of the enhancement increases with an increasing M.

Electron elastic scattering off a Tensor-polarized Deuterium Internal Target

The tensor analyzing power Γ20 in elastic electron-deuteron scattering has been measured in the four momentum transfer region between 1.4 and 3.2 fm~l using the Internal Target Facility at NIKHEF. Tensor-polarized deuterium is produced in an Atomic Beam Source and injected into a storage cell. Scattered electrons and recoil deuterons were detected in coincidence with two large acceptance nonmagnetic detectors.

Electromagnetic and gravitomagnetic structure and radii of nucleons

Taking into account the PDFs, obtained by different Collaborations, the momentum transfer dependenceof GPDs of the nucleons is obtained. The calculated electromagnetic and gravitomagnetic form factors ofnucleons are used for the description of different form factors and the nucleons elastic scattering in a wide energy and momentum transfer region with a minimum number of fitting parameters. The electromagnetic and gravitomagnetic radii of the nucleon are calculated using the obtained momentum transfer dependence of GPDs with different forms of PDFs obtained by different Collaborations. The comparison of the calculations, taking into account the PDFs obtained by different Collaborations, of ean square electromagnetic and gravitomagnetic radii of nucleons is made.

CALIPSO lidar calibration at 532 nm: version 4 daytime algorithm

The Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission released version 4.00 of their lidar level 1 data set in April of 2014, and subsequently updated this to version 4.10 in November of 2016. The primary difference in the newly released version 4 (V4) data is a suite of updated calibration coefficients calculated using substantially revised calibration algorithms. This paper describes the revisions to the V4 daytime calibration procedure for the 532 nm parallel channel. As in earlier releases, the V4 daytime calibration coefficients are derived by scaling the raw daytime signals to the calibrated nighttime signals acquired within a calibration transfer region, and thus the new V4 daytime calibration benefits from improvements made to the V4 532 nm nighttime calibration. The V4 calibration transfer region has been moved upward from the upper troposphere to the more stable lower stratosphere. The identification of clear-air columns by an iterative thresholding scheme, crucial to selecting the observation regions used for calibration, now uses uncalibrated 1064 nm data rather than recursively using the calibrated 532 nm data, as was done in version 3 (V3). A detailed account of the rationale and methodology for this new calibration approach is provided, along with results demonstrating the improvement of this calibration over the previous version. Extensive validation data acquired by NASA's airborne high spectral resolution lidar (HSRL) shows that during the daytime the average difference between collocated CALIPSO and HSRL measurements of 532 nm attenuated backscatter coefficients is reduced from 3.3 %±3.1 % in V3 to 1.0 %±3.5 % in V4.

CALIPSO Lidar Calibration at 532 nm: Version 4 Daytime Algorithm

The Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission released version 4.00 of their lidar level 1 data set in April of 2014, and subsequently updated this to version 4.10 in November of 2016. The primary difference in the newly released version 4 (V4) data is a suite of updated calibration coefficients calculated using substantially revised calibration algorithms. This paper describes the revisions to the V4 daytime calibration procedure for the 532 nm parallel channel. As in earlier releases, the V4 daytime calibration coefficients 15 are derived by scaling the raw daytime signals to the calibrated nighttime signals acquired within a calibration transfer region, and thus the new V4 daytime calibration benefits from improvements made to the V4 532 nm nighttime calibration. The V4 calibration transfer region has been moved upward from the upper troposphere to the more stable lower stratosphere. The identification of clear-air columns by an iterative thresholding scheme, crucial to selecting the observation regions used for calibration, now uses uncalibrated 1064 nm data rather than recursively using the 20 calibrated 532 nm data as was done in version 3 (V3). A detailed account of the rationale and methodology for this new calibration approach is provided, along with results demonstrating the improvement of this calibration over the previous version. Extensive validation data acquired by NASA's airborne high spectral resolution lidar (HSRL) shows that during the daytime the average difference between collocated CALIPSO and HSRL measurements of 532 nm attenuated backscatter coefficients is reduced from 3.3 % ± 3.1 % in V3 to 1.0 % ± 3.5 % in V4.