Three-dimensional grain resolved strain mapping using laboratory X-ray diffraction contrast tomography: theoretical analysis

Laboratory diffraction contrast tomography (LabDCT) is a recently developed technique to map crystallographic orientations of polycrystalline samples in three dimensions non-destructively using a laboratory X-ray source. In this work, a new theoretical procedure, named LabXRS, expanding LabDCT to include mapping of the deviatoric strain tensors on the grain scale, is proposed and validated using simulated data. For the validation, the geometries investigated include a typical near-field LabDCT setup utilizing Laue focusing with equal source-to-sample and sample-to-detector distances of 14 mm, a magnified setup where the sample-to-detector distance is increased to 200 mm, a far-field Laue focusing setup where the source-to-sample distance is also increased to 200 mm, and a near-field setup with a source-to-sample distance of 200 mm. The strain resolution is found to be in the range of 1–5 × 10−4, depending on the geometry of the experiment. The effects of other experimental parameters, including pixel binning, number of projections and imaging noise, as well as microstructural parameters, including grain position, grain size and grain orientation, on the strain resolution are examined. The dependencies of these parameters, as well as the implications for practical experiments, are discussed.

Hobotnica: exploring molecular signature quality

A Molecular Features Set (MFS), is a result of a vast diversity of bioinformatics pipelines. The lack of a “gold standard” for most experimental data modalities makes it difficult to provide valid estimation for a particular MFS's quality. Yet, this goal can partially be achieved by analyzing inner-sample Distance Matrices (DM) and their power to distinguish between phenotypes. The quality of a DM can be assessed by summarizing its power to quantify the differences of inner-phenotype and outer-phenotype distances. This estimation of the DM quality can be construed as a measure of the MFS's quality. Here we propose Hobotnica, an approach to estimate MFSs quality by their ability to stratify data, and assign them significance scores, that allow for collating various signatures and comparing their quality for contrasting groups.

Hobotnica: exploring molecular signature quality

A Molecular Features Set (MFS), is a result of vast diversity of bioinformatics pipelines. In case when MFS is used for further analysis to distinguish between phenotypes, it is often referred to as a signature. Lack of the "gold standard" for most experimental data modalities makes it hard to provide valid estimation for a particular MFS's quality. Yet, this goal can partially be achieved by analyzing inner-sample Distance Matrix (DM) and their power to distinguish between phenotypes. The quality of a DM can be assessed by summarizing its power to quantify the differences of inner-phenotype and outer-phenotype distances. This estimation of the DM quality can be construed as a measure of the MFS's quality. Here we propose Hobotnica, an approach to estimate MFS's quality by their ability to stratify data, and assign them significance scores, that allows for collating various signatures and comparing their quality for contrasting groups.

PENENTUAN GARIS PANTAI MENGGUNAKAN FOTO UDARA DARI WAHANA TANPA AWAK (Studi Kasus Pantai Ujong Batee Aceh)

Garis pantai merujuk Undang-undang No 4 tahun 2011 pasal 13 merupakan garis pertemuan antara daratan dengan lautan yang dipengaruhi oleh pasang surut air laut. Pembentukan garis pantai membutuhkan data Digital Elevation Model (DEM) diwilayah pesisir dengan resolusi dan ketelitian tinggi, sementara teknologi foto udara memiliki kemampuan dalam hal ekstraksi point ketinggian (point cloud) dari titik sekutu antar foto udara yang bertampalan dan juga memiliki kelebihan menghemat waktu pekerjaan dan biaya jika dibandingkan dengan pengukuran terestris. Penelitian ini bertujuan untuk menguji hasil pembentukan DEM dari data foto udara yang selanjutnya digunakan untuk pembentukan garis pantai di pantai Ujong Batee Aceh. Proses pengumpulan data menggunaan wahana Multi rotor DJI Mavic Pro. Jumlah titik Ground Control Point (GCP) adalah 10 titik yang tersebar secara merata untuk seluruh area yang dipetakan. Hasil Ground Sample Distance adalah 1,97 cm/pixel dengan cakupan area yaitu 16,8 hektar. Hasil uji akurasi vertikal DEM menggunakan 167 Independent Check Point (ICP) adalah sebesar 0,863 m, dapat disimpulkan bahwa data foto udara kamera non-metrik dalam penelitian ini memenuhi ketelitian vertikal peta RBI pada skala 1:5.000 kelas I (SNI Ketelitian peta dasar 8202:2019). Pembentukan garis pantai menggunakan DEM dari foto udara yang sudah dikoreksi menggunakan model pasut BIG sehingga datum vertikal dari DEM adalah muka air rata- rata. Garis pantai yang terbentuk pada lokasi penelitian hanya garis pantai pasang tertinggi dan muka air laut rata-rata. Pemotretan udara untuk mendapatkan DEM diwilayah pesisir sebaiknya dilakukan pada saat air surut untuk memperoleh garis pantai air muka laut rata-rata dan pasang tertinggi.

Orientação Exterior de Imagens CBERS-4/PAN Utilizando Modelos Rigorosos

O processo de correção geométrica em imagens orbitais é uma etapa indispensável, em que é possível a geração de produto cartográfico mais confiável, o qual pode ser utilizado em inúmeras aplicações. Os satélites de imageamento possuem sensores embarcados integrados com outros dispositivos que, em conjunto, são capazes de fornecer as imagens orbitais, as quais apresentam diferentes níveis de detalhamento e de acurácia posicional. Desta forma, é importante analisar a qualidade das imagens orbitais do CBERS-4/PAN na banda pancromática, cujo GSD (Ground Sample Distance) é de 5 metros, bem como quais procedimentos podem ser adotados para melhorá-las. Além do CBERS-4 ser considerado um satélite recente, são escassos os estudos referentes à confiabilidade posicional e correção geométrica dos produtos gerados, principalmente das imagens do sensor PAN (Panchromatic and Multispectral Camera). Para a orientação exterior das imagens CBERS-4/PAN foi utilizado o modelo matemático rigoroso baseado nas equações de colinearidade adaptadas para o sensor de varredura linear. Foram utilizados dados orbitais como injunções relativas, e variou-se a quantidade de pontos de apoio - 15, 10 e 5 pontos, cujas coordenadas são oriundas dos limites de propriedades rurais cadastrados no INCRA (Instituto Nacional de Colonização e Reforma Agrária). Foram geradas imagens corrigidas geometricamente com acurácia posicional planimétrica mais confiáveis (10 a 15 m).

Design of Harmonic AFM Probe Subjected to van der Waals Force in the Modified Couple Stress Theory

The conventional design of harmonic AFM probe geometry is made in neglect of the effects of the size-dependency factor and the tip-sample interacting force. Obviously, the effect of these two factors on the natural frequencies of a probe is significant. In this study, the effects of the two factors on the integer-multiples relation among frequencies are investigated. In this study, the effects of the two factors on the integer-multiples relation among frequencies are investigated. It is discovered that, in general, the integer-multiples relations of the probe’s frequencies in the classical model does not be kept as the same as that in the system with the effect of the size-dependency factor under the same material and geometry properties of probe. In addition, when the probe is used to measure the sample, the deviation of the relations will happen. The smaller the tip-sample distance is, the larger the deviation of integer-multiples frequencies is. The analytical method is presented here such that during scanning a sample at some tip-sample distance, the material and geometry properties of the probe can be tuned to the integer-multiples relation of resonant frequencies. Moreover, five similarity conditions among the systems with and without the effects of size-dependency and the tip-sample interacting force are discovered. According to these conditions, the integer-multiples relation is kept in different systems.