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Wyniki wyszukiwania dla: laser computed tomography
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Non-Destructive Assessment of Masonry Pillars using Ultrasonic Tomography
PublikacjaIn this paper, a condition assessment of masonry pillars is presented. Non-destructive tests were performed on an intact pillar as well as three pillars with internal inclusions in the form of a hole, a steel bar grouted by gypsum mortar, and a steel bar grouted by cement mortar. The inspection utilized ultrasonic stress waves and the reconstruction of the velocity distribution was performed by means of computed tomography. The...
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Morphological and electrochemical characterization of ceramic carbon foam electrodes water treatment applications
Dane BadawczeThis dataset contains morphological and electrochemical characterization of ceramic carbon foam employed as an electrode (CFFE) for the oxidation of a target pollutant. The dataset includes:
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Wykorzystanie tomografii komputerowej przy analizie jakości zacementowania - migracja gazu
PublikacjaArtykuł przedstawia opis zjawiska znanego w wiertnictwie otworowym jako migracja gazu. Opisano główne przyczyny powstawania tego negatywnego zjawiska polegającego na przepływie gazów a także płynów w zaczynie cementacyjnym lub kamieniu cementowym. Przygotowano próbki imitujące zacementowany odcinek rur okładzinowych. Skupiono się na wykorzystaniu tomografii komputerowej, oraz analizie zrekonstruowanego trójwymiarowego obrazu, w...
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THE USE OF THE Ti-13Zr-13Nb ALLOY POWDER FOR MANUFACTURING OF PROSTHETIC PARTS BY SELECTIVE LASER MELTING
PublikacjaThe 3D printing is a manufacturing technique belonging to the additive methods able to prepare the designed parts for various purposes. The present reasearch was aimed to fabricate the prosthetic foundations and bridges made of the new Ti-13Zr-13Nb alloy by the selective laser melting (SLM) of a metal powder. The scanning electron examinations and micro scanning tomography were used to investigate the surface quality and intrinsic...
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Experimental investigations of damage evolution in concrete during bending by continuous micro-CT scanning
PublikacjaThe paper describes experimental investigation results of fracture in notched concrete beams under quasi-static three-point bending. To visualize 3D fracture in concrete under bending, an extended X-ray micro-computed tomography system was used, i.e. the tomography system SkyScan 1173 was connected to the loading machine ISTRON 5569. This combined system enabled to shot images of deforming concrete beams during a continuous deformation...
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Lung perfusion parameters in the diagnosis of diabetic pulmonary microangiopathy
PublikacjaThis paper presents the role of perfusion computed tomography (pCT) in the diagnosis of diabetic pulmonary microangiopathy. Our previous works have shown that perfusion parameters are useful in the diagnosis of diabetic pulmonary microangiopathy. In this article we focus on conditions that are necessary for such the diagnosis and introduce method of classification no microangiopathy vs. microangiopathy based on logistic regression....
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Silica In Silico: A Molecular Dynamics Characterization of the Early Stages of Protein Embedding for Atom Probe Tomography
PublikacjaA novel procedure for the application of atom probe tomography (APT) to the structural analysis of biological systems, has been recently proposed, whereby the specimen is embedded by a silica matrix and ablated by a pulsed laser source. Such a technique, requires that the silica primer be properly inert and bio-compatible, keeping the native structural features of the system at hand, while condensing into an amorphous, glass-like...
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Computational Methods for Liver Vessel Segmentation in Medical Imaging: A Review
PublikacjaThe segmentation of liver blood vessels is of major importance as it is essential for formulating diagnoses, planning and delivering treatments, as well as evaluating the results of clinical procedures. Different imaging techniques are available for application in clinical practice, so the segmentation methods should take into account the characteristics of the imaging technique. Based on the literature, this review paper presents...
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Comparison of image pre-processing methods in liver segmentation task
PublikacjaAutomatic liver segmentation of Computed Tomography (CT) images is becoming increasingly important. Although there are many publications in this field there is little explanation why certain pre-processing methods were utilised. This paper presents a comparison of the commonly used approach of Hounsfield Units (HU) windowing, histogram equalisation, and a combination of these methods to try to ascertain what are the differences...
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Three-dimensional modeling and automatic analysis of the human nasal cavity and paranasal sinuses using the computational fluid dynamics method
PublikacjaPurpose The goal of this study was to develop a complete workflow allowing for conducting computational fluid dynam- ics (CFD) simulation of airflow through the upper airways based on computed tomography (CT) and cone-beam computed tomography (CBCT) studies of individual adult patients. Methods This study is based on CT images of 16 patients. Image processing and model generation of the human nasal cavity and paranasal sinuses...
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SIMULATIONS OF FRACTURE IN CONCRETE BEAMS UNDER BENDING USING A CONTINUUM AND DISCRETE APPROACH
PublikacjaThe paper describes two-dimensional meso-scale results of fracture in notched concrete beams under bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones and air voids. Within continuum mechanics, the simulations were carried out with the finite element method based on a isotropic damage constitutive model enhanced by a characteristic...
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MODELLING OF CONCRETE FRACTURE AT AGGREGATE LEVEL USING DEM BASED ON X-RAY mu CT IMAGES OF INTERNAL STRUCTURE
PublikacjaThe paper describes two-dimensional meso-scale numerical results of fracture in notched concrete beams under quasi-static three-point bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones (ITZs) and air voids. As a numerical approach, the discrete element method (DEM) was used. The concrete micro-structure in calculations was directly...
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Mechanical Design, Construction and Control of a Lower Extremity Exoskeleton Robot Prototype with a new structure in the form of three-wheeled Mobile robot
PublikacjaIn this paper, mechanical design, dynamic modeling, construction and Fuzzy computed torque control of a lab prototype of lower extremity exoskeleton robot with a new structure in the form of three-wheeled Mobile robot is presented. One of the most important applications of next generation of lower extremity exoskeleton robot is usability as smart vehicle. In order to autonomously moving of this robot which is the foundation...
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Nano-particle doped hydroxyapatite material evaluation using Spectroscopic Polarization Sensitive Optical Coherence Tomography
PublikacjaBio-ceramics such as hydroxyapatite (HAp) are widely used materials in medical applications, especially as an interface between implants and living tissues. There are many ways of creating structures from HAp like electrochemical assisted deposition, biomimetic, electrophoresis, pulsed laser deposition or sol-gel processing. Our research is based on analyzing the parameters of the sol-gel method for creating thin layers of HAp....
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Rating mathematical models for first-pass of tracer in pCT lung studies
PublikacjaThis paper presents a comparison of model based on the Gauss function and the most commonly used Gamma-variate model in perfusion computed tomography (pCT) lung studies. It also verifies whether used model affects value of blood volume parameter. Three mean concentration-time curves were created from actual pCT measurements: arterial input function, blood vessels in lungs and lung parenchyma. On the basis of these mean curves we...
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Molecular Imaging and Nanotechnology—Emerging Tools in Diagnostics and Therapy
PublikacjaPersonalized medicine is emerging as a new goal in the diagnosis and treatment of diseases. This approach aims to establish differences between patients suffering from the same disease, which allows to choose the most effective treatment. Molecular imaging (MI) enables advanced insight into molecule interactions and disease pathology, improving the process of diagnosis and therapy and, for that reason, plays a crucial role in personalized...
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ColorNephroNet: Kidney tumor malignancy prediction using medical image colorization
PublikacjaRenal tumor malignancy classification is one of the crucial tasks in urology, being a primary factor included in the decision of whether to perform kidney removal surgery (nephrectomy) or not. Currently, tumor malignancy prediction is determined by the radiological diagnosis based on computed tomography (CT) images. However, it is estimated that up to 16% of nephrectomies could have been avoided because the tumor that had been...
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New method to monitor changes in the subarachnoid width and pial artery pulsation for physiological and clinical research
PublikacjaThere are several medical conditions associated with brain oedema such as traumatic brain injury, intoxication or tumors. Brain edema and related brain parenchyma expansion may lead to compression and subsequent injury of several brain structures. So far, the only method enabling detection and monitoring of the progress a cerebral oedema in a patient, has been monitoring of intracranial pressure (ICP) with a pressure probe inserted...
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EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF CONCRETE BEHAVIOUR AT MESO-LEVEL DURING QUASI-STATIC SPLITTING TENSION
PublikacjaThe paper describes experimental and numerical results of quasi-static splitting tensile tests on concrete specimens at meso-scale level. The loading strip was made of plywood or steel. Fracture in concrete was detected at the aggregate level by means of three non-destructive methods: 3D x-ray micro-computed tomography, 2D scanning electron microscope and manual 2D digital microscope. The discrete element method was used to directly...
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Application of Rapid Prototyping technology in the manufacturing of turbine blade with small diameter holes
PublikacjaThe article presents the possibilities of using Rapid Prototyping (RP) technology in the manufacturing of turbine blades with small diameter holes. The object under investigation was gas turbine blade with small diameter cooling holes and holes for generating longitudinal vortices. A turbine blade model was produced by means of Direct Metal Laser Sintering (DMLS) technology and subsequently validated in terms of detection and accuracy...
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Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants
PublikacjaSurface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb- 13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of...
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Numerical analysis of the ostiomeatal complex aeration using the CFD method
PublikacjaWe aimed to analyse ostiomeatal complex (OMC) aeration using the computational fluid dynamics (CFD) method of simulation based on human craniofacial computed tomography (CT) scans. The analysis was based on CT images of 2 patients: one with normal nose anatomy and one with nasal septal deviation (NSD). The Reynolds-Average Simulation approach and turbulence model based on linear eddy viscosity supplemented with the two-equation...
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Information Extraction from Polish Radiology Reports using Language Models
PublikacjaRadiology reports are vital elements of directing patient care. They are usually delivered in free text form, which makes them prone to errors, such as omission in reporting radiological findings and using difficult-to-comprehend mental shortcuts. Although structured reporting is the recommended method, its adoption continues to be limited. Radiologists find structured reports too limiting and burdensome. In this paper, we propose...
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Investigations on fracture in reinforced concrete beams in 3-point bending using continuous micro-CT scanning
PublikacjaThis study explores a fracture process in rectangular reinforced concrete (RC) beams subjected to quasi-static three-point bending. RC beams were short and long with included longitudinal reinforcement in the form of a steel or basalt bar. The ratio of the shear span to the effective depth was 1.5 and 0.75. The focus was on the load–deflection diagram and crack formation. Three-dimensional (3D) analyses of the size and distribution...
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Investigations of size effect in concrete at aggregate level - experiments and calculations results using discrete element method
PublikacjaSize effect is a fundamental phenomenon in concrete. It is characterised by decreasing strength and increasing brittleness of concrete with increasing size. The thesis includes experimental and theoretical elements. The main goal of the thesis were investigations of a size effect at the aggregate level by taking fracture into account with the discrete element method (DEM) for various failure modes. Comprehensive experiments on...
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Maxillary sinus aeration analysis using computational fluid dynamics
PublikacjaThe maxillary sinus aeration using the computational fluid dynamics (CFD) method based on individual adult patients’ computed tomography (CT) scans were analyzed. The analysis was based on CT images of 4 patients: one with normal nose anatomy and three with nasal septal deviation (NSD) and concha bullosa (CB). The CFD simulation was performed using the Reynolds-Average Simulation approach and turbulence closure based on linear...
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The Effect of Fly Ash Microspheres on the Pore Structure of Concrete
PublikacjaThe fly ash microspheres (FAMs) formed during the mineral transformation stage in coal combustion are hollow spherical particles with a density less than water. This paper presents the results of X‐ray micro‐computed tomography and an automatic image analysis system of the porosity in the structure of hardened concrete with microspheres. Concrete mixtures with ordinary Portland cement and two substitution rates of cement by microspheres—5%...
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Proposal of New Tracer Concentration Model in Lung PCT Study Comparison with Commonly Used Gamma-variate Model
PublikacjaPerfusion computed tomography (pCT) is one of the methods that enable non-invasive imaging of the hemodynamics of organs and tissues. On the basis of pCT measurements, perfusion parameters such as blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) are calculated and then used for quantitative evaluation of the tissue condition. To calculate perfusion parameters it is necessary to approximate...
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Mechanical Performance and Environmental Assessment of Sustainable Concrete Reinforced with Recycled End-of-Life Tyre Fibres
PublikacjaThe presented research’s main objective was to develop the solution to the global problem of using steel waste obtained during rubber recovery during the tire recycling. A detailed comparative analysis of mechanical and physical features of the concrete composite with the addition of recycled steel fibres (RSF) in relation to the steel fibre concrete commonly used for industrial floors was conducted. A study was carried out using...
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Nonlinear dynamic analysis of the pure “buckling” mechanism during blow-out trauma of the human orbit
PublikacjaConsidering the interplay between orbital bones and intraorbital soft tissues, commonly accepted patterns of the blow-out type of trauma within the human orbit require more thorough investigation to assess the minimal health-threatening impact value. Two different three-dimensional finite element method (FEM) models of the human orbital region were developed to simulate the pure “buckling” mechanism of orbital wall fracture in...
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublikacjaIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Insight into the microstructural and durability characteristics of 3D printed concrete: Cast versus printed specimens
PublikacjaThis study presents the comparison of microstructural and durability characteristics of 3D printed concrete (3DPC) depending on its production method (printing or casting). Printed samples with different numbers of layers, as well as a cast specimen with an identical mix composition, were produced and compared, with their microstructural pore and solid characteristics quantitatively and qualitatively investigated. For this purpose,...
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Mechanical Properties of Additively Manufactured Polymeric Materials—PLA and PETG—For Biomechanical Applications
PublikacjaThe study presented herein concerns the mechanical properties of two common polymers for potential biomedical applications, PLA and PETG, processed through fused filament fabrication (FFF)—Material Extrusion (ME). For the uniaxial tension tests carried out, two printing orientations—XY (Horizontal, H) and YZ (Vertical, V)—were considered according to the general principles for part positioning, coordinates, and orientation typically...
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One More Step Towards a Circular Economy for Thermal Insulation Materials—Development of Composites Highly Filled with Waste Polyurethane (PU) Foam for Potential Use in the Building Industry
PublikacjaThe rapid development of the building sector has created increased demand for novel materials and technologies, while on the other hand resulting in the generation of a severe amount of waste materials. Among these are polyurethane (PU) foams, which are commonly applied as thermal insulation materials. Their management is a serious industrial problem, due to, for example, their complex chemical composition. Although some chemical...
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Reactivation of seizure‐related changes to interictal spike shape and synchrony during postseizure sleep in patients
PublikacjaOBJECTIVE: Local field potentials (LFPs) arise from synchronous activation of millions of neurons, producing seemingly consistent waveform shapes and relative synchrony across electrodes. Interictal spikes (IISs) are LFPs associated with epilepsy that are commonly used to guide surgical resection. Recently, changes in neuronal firing patterns observed in the minutes preceding seizure onset were found to be reactivated during postseizure...
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Cyclic behaviour modelling of additively manufactured Ti-6Al-4V lattice structures
PublikacjaThe present work is concerned with the numerical modelling of the cyclic behaviour of Ti-6Al-4V lattice structures. In the study, diamond structures of titanium alloy produced by the additive laser powder bed fusion (LPBF) method with different degrees of relative density were used. Realistic geometric models of the studied mesostructures were generated using computed microtomography, taking into account the imperfections of the...
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Folate/homocysteine metabolism and lung cancer risk among smokers
PublikacjaBackground: Folate and homocysteine are involved in DNA synthesis and methylation processes, which are deregulated during carcinogenesis. Objectives: The aim of this study was to assess the relationship between folate/homocysteine concentrations, the functional polymorphisms of folate/homocysteine genes and lung cancer risk among cigarette smokers. Study design: The study included 132 lung cancer patients and 396 controls from...
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Tomography
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Carotid Artery Stenting and Blood–Brain Barrier Permeability in Subjects with Chronic Carotid Artery Stenosis
PublikacjaFailure of the blood-brain barrier (BBB) is a critical event in the development and progression of diseases such as acute ischemic stroke, chronic ischemia or small vessels disease that affect the central nervous system. It is not known whether BBB breakdown in subjects with chronic carotid artery stenosis can be restrained with postoperative recovery of cerebral perfusion. The aim of the study was to assess the short-term effect...
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Laboratory research on the influence of swelling clay on the quality of borehole cementing and evaluation of clay-cutting wellbore tool prototype
PublikacjaSwelling clay phenomenon is frequently observed during oil and gas drilling operations and has a significant impact on the quality of cementing procedure. Certain types of clayey minerals increase their volume in contact with water-based drilling fluids. After drilling is completed, borehole remains unsupported and filled with waterbased drilling fluids for several hours, before a casing string is inserted and secured with cement....
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Simulating coherent light propagation in a random scattering materials using the perturbation expansion
PublikacjaMultiple scattering of a coherent light plays important role in the optical metrology. Probably the most important phenomenon caused by multiple scattering are the speckle patterns present in every optical imaging method based on coherent or partially coherent light illumination. In many cases the speckle patterns are considered as an undesired noise. However, they were found useful in various subsurface imaging methods such as...
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Regional resting state perfusion variability and delayed cerebrovascular uniform reactivity in subjects with chronic carotid artery stenosis
PublikacjaThe aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis.Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥90% on the ipsilateral side and ≤50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were...
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1D portable optical coherence tomography system
Publikacja—Imaging methods are an expanding branch of technology, which involves data acquisition and analysis of images for research and diagnostics. This paper has been devoted to the description of the optical design for a one-dimensional, portable optical coherence tomography (OCT) system. The Mach-Zehnder interferometer has been designed in the presented study. The description of the construction and applied hardware solutions have...
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Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublikacjaUltrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...
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Gold nanoparticles evaluation using functional optical coherence tomography
PublikacjaThe main object of this research was to assess the ability to characterize the gold nanoparticles using optical modalities like optical coherence tomography. Since the nanoparticles, especially gold one, have been very attractive for medical diagnosis and treatment the amount of research activities have been growing rapidly. The nanoparticles designed for different applications like contrast agents or drugs delivery change the...
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Microcrystalline diamond film evaluation by spectroscopic optical coherence tomography
PublikacjaThis study has focused on the microcrystalline diamond film (MCD) thickness evaluation. For this purpose, optical coherence tomography (OCT) enhanced by spectroscopic analysis has been used as a method of choice. The average thickness of the tested layer was about 1.5 µm, which is below the standard 2-point OCT resolution. In this case, the usefulness of the spectroscopic analysis was confirmed for the evaluation of the thickness...
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Laser Therapy
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Quantitative Active Dynamic Thermal IR-Imaging and Thermal Tomography in Medical Diagnostic
PublikacjaPrinciples of Active dynamic thermal (ADT) IR-imaging and Thermal Tomography are described in details. Basic medical applications of this new modality are also discussed.
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A prototype femtosecond laser system for MEMS fabrication
Publikacjan this article, the concept of a prototype femtosecond laser micromachining system and a femtosecond solid-state Yb:KYW laser is presented. Ultrashort laser pulses have many advantages over the long pulses in laser micromachining, due to their unique ability to interact with different materials without transferring heat to them. This allows very precise and pure laser-processing, clean cuts and sharp edges. A femtosecond laser...
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Detection of petroleum products using optical coherence tomography
PublikacjaIn this work, we present a novel method developed for the analysis of the properties of thin layers for detecting petroleum products on a water surface using a commercially available optical coherence tomography (OCT) system. The spectral density analysis of the signal from a spectroscopic OCT (S-OCT) enables us to perform the precision calculation of the thin layer thickness and other properties like homogeneity, and dispersion,...