The prototype BS-II for computer measurement of biomechanical characteristics of the human cadaverous lumbar spine

Background The new second-generation computer system BS-II (Bio-Spine-II) based on the National Instruments’ development environment has been designed and constructed for evaluating the stability of various surgical fixative methods of the cadaverous lumbar spine (L1–L5). BS-II holds the measured sample using aluminum fixtures and using four computer-controlled stepper motors; it performs a circular movement (warm up of the specimen), programmatically driven extension (back bend), right and left lateral flexion (lateral bend), left and right axial torsion (rotation), and axial compression (pressure). Four strain gauges are used to measure the stiffness of the sample. The movement of individual components (vertebrae) is contactlessly monitored by two CCD (charge couple device) cameras. The obtained data are in digital form continuously stored in the computer memory for further processing. Methods The functionality of the equipment was verified on the cadaverous specimen of the human spine. The stiffness of the sample was measured by strain gauges, and the results were processed using linear regression analysis. Movements of vertebrae were determined by circular discs covered with appropriate patterns. The discs have been linked with the respective vertebrae and were contactlessly monitored by two CCD (charge couple device) cameras and evaluated using digital image processing methods and 2D digital FFT (fast Fourier transformation). Direction and displacement of the individual components were determined by the band of the calculated spectrum. The new device BS-II is controlled by a modifiable computer program designed in the National Instruments’ development environment which allows statistical processing of the sample, including its warming up. Results The computer system BS-II for measurement of biomechanical properties of the spine sample was designed. Functionality of the device was verified by implementation of LUMIR XLIF CAGE implant into a cadaver sample of the human spine. Comparison of the rigidity of the intact and stabilized sample is shown in the graphs of article. The achieved results contributed to certification of the implant into the surgical practice. Conclusion The designed computer BS-II system is designed for biomechanical measurements of the lumbar part of the human spine, especially for verification of surgical fixation methods. The system is based on the knowledge and experience with a manually operated measuring device designed by Palacky University Olomouc. The computer programmatic control allows the user to change the conditions and parameters of the measurement procedure in a planned way, which allows the results to be processed in, among other things, a statistical way. If suitable models are used (3D printing), the BS-II system can be used to verify procedures for surgical stabilization of the spine in the training of future doctors. The obtained data of stiffness and image information are stored in digital form and can be used for next offline sophisticated study of biomechanical properties of specimens (accurate vertebral geometry, statistical processing, 3D printing, etc.). The usefulness of the BS-II system is demonstrated in the case of biomechanical analysis of the implantation of LUMIR XLIF CAGE implant to a human cadaver specimen of the spine.

Analisis Kecepatan Aliran Air Berbasis Metode Laser Speckle Imaging

Telah dilakukan analisis kecepatan aliran air dengan metode Laser Speckle Imaging (LSI). Sistem LSI menggunakan pendekatan forward scattering. Sistem terdiri dari tiga unit yaitu transmitter menggunakan laser He-Ne, receiver menggunakan CCD (Charge Couple Device), dan penampil menggunakan PC. Objek penelitian menggunakan air yang dijatuhkan dari wadah dengan diameter lubang yang divariasikan pada ketinggian yang berbeda. Hasil pengukuran kecepatan aliran air dari wadah berdiameter 1 mm pada ketinggian 50 cm memiliki nilai kecepatan terendah yaitu sebesar 0,73 ml/detik. Nilai tertinggi dihasilkan dari wadah berdiameter 5 mm pada ketinggian 150 cm yaitu sebesar 15,49 ml/detik. Ukuran diameter lubang dan ketinggian jatuh air semakin besar, maka nilai kecepatan aliran air semakin besar. Pengukuran intensitas citra juga dilakukan untuk melihat korelasi dengan kecepatan air. Nilai intensitas terendah yaitu 238,45 a.u diperoleh dari tetesan air dengan diameter 5 mm dan nilai tertinggi yaitu 253,12 a.u diperoleh pada diameter 1 mm. Ukuran diameter wadah semakin besar maka nilai intensitas citra semakin kecil. Intensitas citra berbanding terbalik dengan nilai kecepatan aliran air.Kata kunci : kecepatan alir, butiran hujan, intensitas citra, laser

Analisis Intensitas Citra Tetesan Air dengan Metode Laser Speckle Imaging

Analisis nilai intensitas citra tetesan air dengan metode Laser Speckle Imaging telah dilakukan. Penelitian ini menggunakan sistem perancangan forward-scattering. Sistem terdiri dari tiga unit yaitu transmitter sebagai sumber cahaya menggunakan laser He–Ne, receiver sebagai detektor menggunakan CCD (Charge Couple Device), dan penampil menggunakan PC. Transmitter dan receiver diposisikan sejajar dengan jarak yang telah diatur agar berkas cahaya laser menyinari detektor CCD pada sudut 00 untuk mendapatkan citra spekel. Intensitas citra spekel dikarakterisasi menggunakan 6 manik-manik dengan diameter berbeda (2,15 - 11,91 mm). Nilai intensitas citra spekel tertinggi didapatkan pada diameter manik-manik 2,15 mm yaitu 254,62 a.u dan terendah pada manik-manik 11,91 mm yaitu 224,5 a.u. Hasil karakteriasi menunjukkan bahwa intensitas citra spekel menurun ketika objek yang terdeteksi berukuran lebih besar. Hasil yang sama juga didapatkan menggunakan tetesan air dari tabung yang berlubang dengan diameter 1-7 mm. Citra spekel tetesan air dianalisis menggunakan fungsi autokorelasi untuk mendapatkan ukuran bulir spekel. Ukuran bulir spekel terbesar didapatkan pada diameter lubang tetesan 6 mm yaitu 856,87 µm dan terkecil didapatkan pada diameter lubang tetesan 1 mm yaitu 198,15 µm. Hasil yang diperoleh menunjukkan bahwa semakin besar tetesan air, maka nilai intensitas citra spekel menurun dan ukuran bulir spekel membesar.Kata kunci : citra, forward-scattering, gray scale, laser He-Ne, ukuran bulir spekel

Research on Optical Microscope Measuring Method of External Thread Parameters Based on Charge-Couple Device

As an important component of the fasteners members, threads quality, depending on whether its geometric parameters meet requirements or not, will affect the reliability of the whole machine system. Therefore, geometrical parameters measurement of the thread is especially important. Aiming at the characteristics of the thread teeth type, this paper adopt a machine vision measurement method based on the universal tool microscope and CCD .This paper also analyzes the causes and influences of the teeth shading and proposes a corresponding improvement method, specific to the shading problem in the process of backlighting projection. After experimenting, this method can effectively improve the accuracy and efficiency of the male parameters measurement.

A Técnica de Difração de Elétrons Retro-Espalhados (EBSD) em Microscópio Eletrônico de Varredura (MEV) e sua Aplicação no Estudo de Rochas Deformadas

The electron backscattered diffraction technique in the scanning electron microscope (EBSD/SEM) is based on the diffraction of a high-energy electron beam by the crystalline structure of a given material, in all possible directions within the sample. Some of the diffracted electrons escape from the specimen with virtually the same initial energy, interact with a phosphorescent screen and the generated EBSP pattern can be picked up with a low-luminosity charge couple device (CCD) camera. These patterns can be indexed using pre-determined patterns for a large variety of minerals, which allows the determination of complete orientation of each single mineral within an aggregate. In this paper we briefly discuss the physical aspects related to the diffraction of an electron beam by crystalline matter and how the EBSP patterns are generated. We also present a short introduction of the necessary instruments to acquire EBSD data, as well as the calibration procedures, acquisition and indexing software of EBSPs. The pitfalls of the technique and possible error sources are also discussed with examples. Considering the scarce availability of literature on geological sample preparation, the polishing method of silicate-rich rocks for EBSP is described in detail in the last part of this paper.