Orientation Dependence of High Cycle Fatigue Behavior of a Oriented Single-Crystal Nickel-Based Superalloy

High cycle fatigue failure has been recognized as one of the major forms of failure of aero-engine blades. This paper presents the high cycle fatigue testing of a Ni-based superalloy near <111> orientation at 800 °C. The fracture morphology and dislocation configuration were analyzed in detail by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to indicate the influence of orientation deviation degree on the high cycle fatigue properties. The results show that the orientation deviation significantly affects the initiation of the slip systems, which is closely related to fatigue performance. The best fatigue life appears on the precise <111> orientation, and the deformation behavior is controlled by multiple sets of equivalent <110> {111} slip systems. With the increase in orientation deviation, the fatigue properties of the alloy degenerate significantly. On the boundary of <111>-<001>, two groups of <110> {111} slip systems with the maximum Schmid shear stress dominate the deformation behavior. On the other hand, on the <111>-<011> boundary, the formation of stacking faults and rapid cutting of γ’ precipitates results in a negative effect on the fatigue life.

Prediction of Grain Formation and Defects during Solidification in Single Crystal Superalloy Castings

Numerical simulation and prediction of grain formation and defects, including the stray grain and high angle orientation deviation during directional solidification process of a single crystal superalloy hollow turbine blade are experimentally conducted by means of commercial software ProCAST and backscattering scanning electron microscope. The results show that the initial nucleation amount at the beginning section of the starter block is 104 of magnitude, and the number of grains decreases gradually with the competitive growth, and the number is about 100 at the spiral of the selector. And the orientation distribution of grains is close to <001> direction, with the orientation deviation between 10° and 15°. Moreover, with the increase of withdrawal rate, the curvature of isoline of liquidus of single crystal blade increases, and the tendency to form stray grains defects increases. The grain with a large deviation from orientation blocks the growth of other grains at the first rotating transition site of the selector, and then gradually grows and solidifies to form the final blade.

The Machine Vision Measurement Module of the Modularized Flexible Precision Assembly Station for Assembly of Micro- and Meso-Sized Parts

The machine vision measurement module is indispensable for the Modularized Flexible Precision Assembly Station (MFPAS), which is a fully automatic assembly system being developed at Dalian University of Technology (DUT). MFPAS consists of basic and additional modules, and are expected to be flexible, expandable, and re-configurable to adapt to a variety of parts with a large size range, requiring the machine vision measurement module to be able to achieve accurate measurement of position, as well as orientation of the parts with different size scale. An automatic zooming vision system was set up for evaluation and final integration in MFPAS. Pixel equivalent, principal point and orientation deviation of images were analyzed and experimentally studied using different magnifications of the lens. A new template with circular patterns of different diameters was designed for zoom-lens calibration. The experiments show that the measurement error caused by the variation of the pixel equivalent, principal point and orientation is estimated under 10 μm without online calibration. When high accuracy is required, online calibration can be employed during assembly. The evaluation results of the vision system with or without on-line calibration were given for a better trade-off between accuracy and efficiency during assembly.

Grain Orientation Optimization of Two-Dimensional Grain Selector during Directional Solidification of Ni-Based Superalloys

The grain selection method is widely used in industry to produce Ni-based single crystal superalloys. A Z-form two-dimensional (2D) grain selector was designed to obtain high-quality single crystals. To control grain orientation deviation, one of the most important defects of the single crystal superalloys in casting, Z-form 2D grain selectors with different take-off angle were investigated in this study. The MM247LC superalloy single crystal samples were obtained by the Bridgman method modified by the Z-form grain selectors in this study. The Electron Backscattered Diffraction (EBSD) and the Optical Microscopy (OM) were used to observe and measure the grain selection growth and the microstructural evolution and orientation of the single crystal were also discussed. The results show that a Z-form 2D grain selector with an appropriate take-off angle can significantly reduce the deviation of the grain orientation. A single crystal superalloy with a deviation angle less than 6° can be obtained effectively when the take-off angle was 40°.

Path Correction of the Boom Road-Header in Coal Mining Based on State Estimation

Trajectory planning and tracking control algorithm based on a position and orientation deviation model are proposed to achieve path correction for the mining boom road-header working underground. The proposed strategy is assessed to be feasible and potentially practicable by simulations, from which the following statements are summarized. Firstly, trajectory planning is necessary since different trajectories correspond to different scenarios about undesirable excavation space, slipping level, and power consumption. Secondly, using the proposed tracking control algorithm, the road-header is guided back onto the expected path in limited adjusting steps, with smoothly varying rotation speeds of the driving wheels and regularly reducing pose errors. Lastly, it shows that by implying the SVD-unscented Kalman filtering in the tracking control, the adverse impacts of process and measurement noises are appeased obviously. This research provides an advisable modeling and valuable simulation for the road-header to achieve robotic operation underground.

KRITIK SOSIAL SEBUAH CINTA (DALAM SENI LUKIS)

<p><strong>ABSTRAK</strong></p><p><strong> </strong></p><p>Jurnal ini menginterpretasikan gagasan imajinasi penulis dalam judul kritik sosial sebuah cinta sebagai tema utama. Terdapat beberapa permasalahan yang dibahas dalam hal ini, yaitu; 1) hubungan antara cinta dengan kondisi sosial masyarakat yang digambarkan dalam seni lukis, 2) membahas tema kritik sosial sebuah cinta dalam seni lukis?, 3) memvisualisasikan kritik tentang cinta dalam sudut pandang sosial melalui karya seni lukis. Cinta merupakan hasrat naluriah manusia yang diberikan oleh Tuhan, cinta melibatkan perasan emosi yang dalam, dan berefek keindahan bagi penikmatnya. Aktifitas bercinta sebagai pengungkapan hasrat rasa saling cinta antar sesama manusia, menjadi aktifitas yang terlarang ketika melanggar norma sosial kesusilaan, dan dapat menjerumuskan seseorang ke arah degradasi moral serta memberikan dampak negatif secara</p><p>psikologis, seperti penyimpangan orientasi seksual, depresi, hingga terjadi kasus bunuh diri. Sehingga pada kasus tertentu dapat mengakibatkan tindakan diluar akal sehat dan tidak berperikemanusiaan seperti aborsi dan kasus pembunuhan. Penulis tertarik mengambil tema tersebut, dikarenakan penulis terketuk hati nuraninya ingin memaparkan sudut pandangnya tentang kritik sosial dari degradasi moral yang berkembang di masyarakat yang di atas namakan cinta. Tujuan dari penulis ialah menjadikan karya lukis sebagai media kritik atas penyimpangan sosial yang terjadi di masyarakat serta Mendiskripsikan degradasi moral manusia akibat pemahaman yang dangkal tentang cinta. Metode Penciptaan melaui penggalian ide dari pengamatan dan sebuah perenungan, dan hasil pengamatan dikonsep melalui rancangan sketsa yang ditata berdasarkan asas</p><p>keseni rupaan, tahapan terakhir ialah, memindahkan ide yang terkonsep ke dalam kanvas dengan cat minyak, yang di padu dengan sapuan kuas teknik opaque. Hasil karya yang diolah melalui pendekatan simbolisme visual yang bersifat komunikatif dan umum, yang dikemas secara estetik, diharapan penikmat tertarik untuk melihat apa yang disampaikan oleh karya lukis serta pesan moral yang terkandung di dalamnya.</p><p> </p><p><strong>Kata kunci: </strong>kritik sosial, cinta, seni lukis.</p><p> </p><p><strong><em>ABSTRACT</em></strong></p><p><em>This journal interprets the idea of the author’s imagination in the title “Kritik Sosial Sebuah Cinta” as the main theme. There are several problems discussed in this regard, namely: 1) the relationship between love and the social conditions of society described in painting arts, 2) discussing the theme of social criticism of love in painting, 3) visualizing criticism of love in a social perspective through love. Love is an instinctive desire of human given by God. Love involves deep emotional feelings, and has beautiful effect for the connoisseurs. The act of making love as an expression of mutual love between human beings is prohibited when it is violating social norms of decency and can plunge someone towards moral degradation, have a negative psychological impact, such as sexual orientation deviation, depression, and suicide. In certain cases, it can lead to the actions beyond common sense and inhumane such as abortion and murder cases. The author is interested in</em></p><p><em>taking the theme because of his consciousness to explain his point of view about social criticism on moral degradation in the name of love that develops in the community. The author aims to make painting as a mediaof criticism on social deviations that occur in society and to describe the degradation of human moral due to superficial understanding of love. The creation method is through extracting ideas from observations and contemplation, and the results are conceptualized through sketch designs arranged based on the principles of visual arts. The final stage is to move the conceptual ideas into canvas with oil paint, which are combined with opaque techniques. The work that is processed through the communicative and general visual symbolism approach, which is packed aesthetically, is expected to make the audience interested in seeing what is conveyed by the painting and the moral messages contained in it. </em></p><p><em> </em></p><p><strong><em>Keywords: </em></strong><em>social criticism, love, painting arts.</em></p>

The Influence of Pin Deviation on the Fracture Correction and the Fixator Adjustment with Sensitivity and Kinematic Analysis

Fracture correction is important orthopedics operation and can be performed by unilateral external fixator. Due to pin deviations being inevitable during the operation, searching the impacts of pin deviation on the fracture correction and fixator joint adjustment are important. This study puts forward evaluation index with sensitivity analysis for investigating the impact of three orientation deviations and three position deviations on fracture correction. Meanwhile, based on a clinical case from a 28-year-old female, the influence of pin deviation on the adjustment of fixator joints was analyzed by inverse kinematic method. Different pin deviations have different sensitivity; the sensitivity of orientation deviation is relatively larger than position deviation. The existence of pin deviation will result in the change of the adjustment value of fixator joints. In addition, the experiments of seven situations were established to verify the analytical results. This study revealed the sensitivity of different pin deviations which can also be used to predict the adjustment value of fixator joints and the accuracy of fracture correction. This research also helps to reduce operation time and decrease damage to soft tissue by reducing the frequency of inserting pins.