Ground validation of GPM IMERG-F precipitation products with the point rain gauge records on the extreme rainfall over a mountainous area of Sumatra Island

Accurate satellite precipitation estimates over areas of complex topography are still challenging, while such accuracy is of importance to the adoption of satellite data for hydrological applications. This study evaluated the ability of Integrated Multi-satellitE Retrievals for GPM -Final (IMERG) V06 product to observe the extreme rainfall over a mountainous area of Sumatra Island. Fifteen years of optical rain gauge (ORG) observation at Kototabang, West Sumatra, Indonesia (100.32°E, 0.20°S, 865 m above sea level), were used as reference surface measurement. The performance of IMERG-F was evaluated using 13 extreme rain indexes formulated by the Expert Team on Climate Change Detection and Indices (ETCCDI). The IMERG-F overestimated the values of all precipitation amount-based indices (PRCPTOT, R85P, R95P, and R99P), three precipitation frequency-based indices (R1mm, R10mm, R20mm), one precipitation duration-based indices (CWD), and one precipitation intensity-based indices (RX5day). Furthermore, the IMERG-F underestimated the values of precipitation frequency-based indices (R50mm), one precipitation duration-based indices (CDD), one precipitation intensity-based indices (SDII). In terms of correlation, only five indexes have a correlation coefficient (R) > 0.5, consistent with Kling–Gupta Efficiency (KGE) value. These results confirm the need to improve the accuracy of the IMERG-F data in mountainous areas.

In vitro response of THP-1 derived macrophages to antimicrobially effective PHMB-coated Ti6Al4V alloy implant material with and without contamination with S. epidermidis and P. aeruginosa

Aim Periprosthetic joint infections are a devastating complication after arthroplasty, leading to rejection of the prosthesis. The prevention of septic loosening may be possible by an antimicrobial coating of the implant surface. Poly (hexamethylene) biguanide hydrochloride [PHMB] seems to be a suitable antiseptic agent for this purpose since previous studies revealed a low cytotoxicity and a long-lasting microbicidal effect of Ti6Al4V alloy coated with PHMB. To preclude an excessive activation of the immune system, possible inflammatory effects on macrophages upon contact with PHMB-coated surfaces alone and after killing of S. epidermidis and P. aeruginosa are analyzed. Methods THP-1 monocytes were differentiated to M0 macrophages by phorbol 12-myristate 13-acetate and seeded onto Ti6Al4V surfaces coated with various amounts of PHMB. Next to microscopic immunofluorescence analysis of labeled macrophages after adhesion on the coated surface, measurement of intracellular reactive oxygen species and analysis of cytokine secretion at different time points without and with previous bacterial contamination were conducted. Results No influence on morphology of macrophages and only slight increases in iROS generation were detected. The cytokine secretion pattern depends on the surface treatment procedure and the amount of adsorbed PHMB. The PHMB coating resulted in a high reduction of viable bacteria, resulting in no significant differences in cytokine secretion as reaction to coated surfaces with and without bacterial burden. Conclusion Ti6Al4V specimens after alkaline treatment followed by coating with 5–7 μg PHMB and specimens treated with H2O2 before PHMB-coating (4 μg) had the smallest influence on the macrophage phienotype and thus are considered as the surface with the best cytocompatibility to macrophages tested in the present study.

LANDSLIDE MONITORING USING CLOSE RANGE PHOTOGRAMMETRY

This paper presents the preliminary results of a simulation study on the production of low cost Digital Elevation Model (DEM) for a landslide study area in Seri Iskandar, Perak. The important objective of this paper is to present the potentiality of Close Range Photogrammetry (CRP) as a data acquisition tool in producing a Digital Elevation Model (DEM) by using data from surface measurement. This method was applied using stereopair photographs captured data from ground level detection, or known as close range photogrammetry with the use of a digital camera mounted on a tripod as a tool for data collection. Close Range Photogrammetry (CRP) applications is useful for mapping of areas that are difficult and risky to point manpower on terrain that consist of steep and dangerous slopes. Conventional methods require measurement using Electronic Distance Measuring (EDM), but this method is very costly and requires a survey team placed on the land site area. The research data were carried out with two different epoch data. The outcome proves that CRP can produce DEM with less cost compared to other methods.

Surface Measurement of a Large Inflatable Reflector in Cryogenic Vacuum

The metrology of membrane structures, especially inflatable, curved, optical surfaces, remains challenging. Internal pressure, mechanical membrane properties, and circumferential boundary conditions imbue highly dynamic slopes to the final optic surface. Here, we present our method and experimental results for measuring a 1 m inflatable reflector’s shape response to dynamic perturbations in a thermal vacuum chamber. Our method uses phase-measuring deflectometry to track shape change in response to pressure change, thermal gradient, and controlled puncture. We use an initial measurement as a virtual null reference, allowing us to compare 500 mm of measurable aperture of the concave f/2, 1-meter diameter inflatable optic. We built a custom deflectometer that attaches to the TVAC window to make full use of its clear aperture, with kinematic references behind the test article for calibration. Our method produces 500 × 500 pixel resolution 3D surface maps with a repeatability of 150 nm RMS within a cryogenic vacuum environment (T = 140 K, P = 0.11 Pa).

Solving surface deformation of radio telescope antenna by artificial neural network

Recent investigations have derived the relation between the near-field plane amplitude and the surface deformation of reflector antenna, namely deformation-amplitude equation (DAE), which could be used as a mathematical foundation of antenna surface measurement if an effective numerical algorithm is employed. Traditional algorithms are hard to work directly due to the complexity mathematical model. This paper presents a local approximation algorithm based on artificial neural network (ANN) to solve DAE. Length factor method is used to construct a trial solution for the deformation, which ensures the final solution always to satisfy the boundary conditions. To improve the algorithm efficiency, Adam optimizer is employed to train the network parameters. Combining the application of data normalization method proposed in this paper and a step-based learning rate, a further optimized loss function could be converged quickly. The algorithm proposed in this paper could effectively solve partial differential equations (PDEs) without boundary conditions such as DAE, which at the same time contains the first-order and the second-order partial derivatives, and constant terms. Simulation results show that compared with the original algorithm by FFT, this algorithm is more stable and accurate, which is significant for the antenna measurement method based on DAE.

Application of 3D cameras to assess the quality of soil cultivation in agriculture

Currently, electronic devices are widely used in modern precision farming technology. Soil surface measurement is solved with single-purpose handheld instruments that are placed in the field before passing a tillage machine such as a plow or harrow and after tilling the soil. Laser, photogravimetric and synthetic aperture radar systems are used for non-contact measurement of soil roughness and uniformity. Measurements to calibrate the camera output were carried out at three height levels: 500 mm, 1000 mm and 1500 mm. The indicated measuring heights have been selected for possible applications in agricultural soil research, for example when determining the quality of the treated soil during plowing after passing the tillage machine. Measurements can be used to determine the condition of the soil before and after treatment. The system is easy to use and does not require special and additional expensive software. The use of 3D cameras is effective for determining the state of soil cultivation and a promising direction for adjusting the parameters of the tillage machine. Keywords: 3D CAMERA; MODEL; UNEVENNESS OF THE SOIL, TILLAGE MACHINE