Mathematical Modelling of the Electrical Discharge Mechanical Alloying Process

AbstractIn the paper, a comprehensive study of the electro-discharge mechanical alloying with using brush electrode is presented. This kind of a novel method is denoted as BEDMA (Brush Electro-Discharge Mechanical Alloying) and it combines features of electrical discharge machining with thermo-mechanical treatment. Electrode is being made of material which is to be alloyed on the part surface. A mathematical modelling of the thermal processes and mechanical action during the interaction of a single filament on the machined surface have been developed and used to estimation of the material transfer rate

Selected properties of high velocity oxy liquid fuel (HVOLF) - sprayed nanocrystalline WC-CO INFRALLOYTM S7412 coatings modified by high energy electric pulse

The paper presents a brief study of selected properties of HVOLF-sprayed nanocrystalline WC-Co InfralloyTM S7412 coatings modified by the application of a high energy electric pulse. The anti-wear coatings were applied on carbon steel with the use of High Velocity Oxy Liquid Fuel (HVOLF) spraying system TAFA – JP-5000. The process was modified by the application of the SST France & Vision Lasertechnik device WS 7000 S. The resultant type of coatings may be applied to increase the abrasive wear resistance of tools and machine parts. The properties of the powders and coatings were studied using metallographic methods and EDS analyses. The microhardness and nanohardness of the resultant layers were measured and Young’s modulus of elasticity was determined

Computed Tomography and Scanning Electron Microscopy Analysis of a Friction Stir Welded Al-Cu Joint

The study aimed touse3D computed tomography (CT) to analyse a joint between two dissimilar materials produced by friction stir welding (FSW). As the materials joined, i.e., aluminum and copper, differ in properties (e.g., density and melting point), the weld is predicted to have an inhomogeneous microstructure. The investigations involved applying microfocus computed tomography (micro-CT) to visualize and analyze the volumetric structure of the joint. Volume rendering is extremely useful because, unlike computer modelling, which requires many simplifications, it helps create highly accurate representations of objects. Image segmentation into regions was performed through global gray-scale thresholding. The analysis also included elemental mapping of the weld cross-sections using scanning electron microscopy (SEM) and examination of its surface morphology by means of optical microscopy (OP). The joint finds its use in developing elements used in the chemical, energetics and aerospace industries, due to the excellent possibilities of combining many different properties, and above all, reducing the weight of the structure

Project Status of the Polish Synchrotron Radiation Facility Solaris

Abstract in Undetermined The Polish synchrotron radiation facility Solaris is being built at the Jagiellonian University in Krakow. The project is based on an identical copy of the 1.5 GeV storage ring being concurrently built for the MAX IV project in Lund, Sweden. A general description of the facility is given together with a status of activities. Unique features associated with Solaris are outlined, such as infrastructure, the injector and operational characteristics

Clostridium difficile infection in Polish pediatric outpatients with inflammatory bowel disease

The prevalence of Clostridium difficile infection (CDI) in pediatric patients with inflammatory bowel disease (IBD) is still not sufficiently recognized. We assessed the prevalence of CDI and recurrences in outpatients with IBD. In addition, the influence of IBD therapy on CDI and antimicrobial susceptibility of the potentially causative C. difficile strains was assessed. This was a prospective, single-center, observational study. All specimens were obtained between January 2005 and January 2007 from the IBD outpatient service and screened for C. difficile and its toxins. C. difficile isolates were genotyped by PCR ribotyping. Diagnosis of Crohn’s disease (CD) and ulcerative colitis (UC) was based on Porto criteria. Severity of disease was assessed using the Hyams scale (for Crohn’s disease) and the Truelove–Witts scale (for ulcerative colitis). One hundred and forty-three fecal samples from 58 pediatric IBD patients (21 with Crohn’s disease and 37 with ulcerative colitis) were screened. The risk of C. difficile infection was 60% and was independent of disease type (CD or UC) (χ2 = 2.5821, df = 3, p = 0.4606). About 17% of pediatric IBD patients experienced a recurrence of CDI. All C. difficile strains were susceptible to metronidazole, vancomycin and rifampin. A high prevalence of C. difficile infection and recurrences in pediatric outpatients with IBD was observed, independent of disease type. There was no significant correlation between C. difficile infection and IBD therapy. PCR ribotyping revealed C. difficile re-infection and relapses during episodes of IBD in pediatric outpatients

Euroinżynier 2014

11–13 kwietnia 2014 r. po raz czwarty na Ogólnopolskiej Konferencji Budowlanej Studentów i Doktorantów Euroinżynier spotkali się studenci i wykładowcy z całej Polski. Organizowana przez Studenckie Koło Naukowe Konstrukcji Żelbetowych CONKRET, a przebiegająca pod patronatem rektora Politechniki Krakowskiej prof. dr. hab. inż. Kazimierza Furtaka oraz dziekana Wydziału Inżynierii Lądowej prof. dr. hab. inż. Tadeusza Tatary, konferencja cieszy się ciągle rosnącym zainteresowaniem w budowlanym świecie akademickim

Integrated wideband transmitter for neural recording applications

W artykule przedstawiono projekt scalonego szerokopasmowego nadajnika dla systemu bezprzewodowej rejestracji potencjałów neuronowych. Prezentowany nadajnik został zaimplementowany w technologii CMOS 180 nm i pracuje w paśmie 4 GHz z modulacją OOK. Maksymalna oferowana szybkość transmisji sięga 80 Mb/s. Średni pobór mocy, przy szybkości transmisji 20 Mbit/s i zasięgu 4 m wynosi 1,8 mW. Struktura nadajnika zajmuje powierzchnie 0,4 x 0,75 mm2, na której oprócz elementów aktywnych mieszczą się cewki obwodu rezonansowego generatora LC i wzmacniacza RF. Napięcie zasilania układu wynosi od 1,5 V do 1,8 V, co pozwala na zasilanie nadajnika z jednej baterii pastylkowej. Układ sterujący nadajnika zaimplementowano w ultra niskomocowym układzie FPGA firmy Silicon Blue. Zawiera on kodera FEC, moduł przeplotu danych oraz kontroli mocy transmisji.The paper presents a low power integrated wideband telemetry system for neural recording. The presented system operates in 4 GHz band. It makes use of OOK modulation and offers very high data rate, up to 80 Mbits/s. The proposed system (Fig. 1) consists of an FPGA based controller and an an RF transmitter. The controller implements an FEC encoder, a bit interleaver, a scrambler and a pulse generator driving the RF transmitter. The FEC encoder is based on a bit-serial (233, 255) Reed-Solomon encoder. The scrambler is responsible for producing appropriate numbers of transitions in the transmitted signal to facilitate bit syn-chronization in the receiver. The RF transmitter was implemented in 180 nm CMOS process with an area of 0.4 x 0.75 mm2. It consumes 1.8 mW operating with the 20 Mbits/s data rate and the transmission range set to 4 m. All of the inductors were integrated on the transmit-ter silicon die, so the only external components are power supply bypass capacitors. For the experimental tests of the presented system a dedicated ultra wide-band antenna was designed on a 0.813 mm microwave substrate (Fig. 7). The radiating element (top layer) has dimensions of roughly 16 x 15 mm and the ground plane dimensions are 16 x 12 mm (bottom layer). The antenna features a very wide impedance band-width of 2.45 GHz (reflection coefficient below -10 dB) and operates in the frequency range 3.30 to 5.75 GHz. The antenna gain at the intended center frequency of the system, i.e. 4 GHz, is 2 dBi and VSWR is below 1.2. The accompa-nying receiver makes use of an AD8318 logarithmic detector