A 2D ultrasonic array design incorporating hexagonal-shaped elements for NDE applications

Contemporary 2D Ultrasonic arrays suffer from low SNR and limited steering capabilities. Yet, there is a great desire in the industry to increase the operational frequency, in order to enhance their volumetric imaging resolution. State-of-the art arrays use an orthogonal matrix of rectangular elements as this is a natural step forward from the conventional 1D array structure. The objective of this work is to evaluate properties of triangular, rather than rectangular ceramic pillars in a 1-3 connectivity piezoelectric composite for application in a hexagonal-element 2D array. A 3MHz prototype device exploiting new hexagonal substructure have been manufactured. Measured mechanical cross-coupling level is -21.9dB between neighbouring hexagonal elements, providing validation of simulation result. Corroboration between measured and FE modelled device behaviour is demonstrated

An annular array with fiber composite microstructure for far field NDT imaging applications

This paper describes the design and fabrication of a reduced element count annular array for far field NDT imaging applications, built with a random fiber piezoelectric composite microstructure. An annular array design is considered, spatially it offers axi-symmetric layout while reducing number of array elements, which could potentially result in a significant reduction in the cost and complexity of building an ultrasonic volumetric imaging system. Modelling and preliminary experimental results are presented to evaluate the feasibility of this approach

Enhanced phased array imaging through reverberating interfaces

A key challenge to achieve non-invasive industrial process analysis is the transmission of information through the vessel wall. Typical non-invasive technologies, such as Raman spectroscopy, require an optically transparent 'window' into the process to acquire the process data. In this work, ultrasonic phased arrays were used to image a dynamic process through planar steel vessel walls into a fluid load. Due to the acoustic impedance mismatch at the steel-fluid interface, only a small fraction of the excitation energy comes back to the receiver in the form of useful echoes from the process. Also, the ultrasonic energy that is not transmitted across the steel-fluid interface reverberates within the vessel wall, masking signals that are reflected from within the process. Here, the ultrasonic array was deployed using Full Matrix Capture (FMC) followed by the Total Focusing Method (TFM) that focusses the ultrasonic beam at every pixel in the image. However, the TFM algorithm is not spatial resolved, leading to multiples of the reverberations interfering throughout the desired image region. To extract the signals corresponding to the process fluid, a method has been developed called the Reverberation Pattern Gain Correction Method (RP-GCM). Firstly, the algorithm uses ray-tracing to predict the path length of reverberations from the steel-fluid interface. The signals in the FMC data set corresponding to those reverberations are then windowed and a gain filter applied, prior to application of the regular TFM process. The RP-GCM has been applied to a simulated FMC data set, developed in PZFlex (OnScale, USA). Initial results demonstrate the effectiveness of this method in separating the vessel reverberations from the ultrasonic echoes of interest relating to the process

Intentional weld defect process: From manufacturing by robotic welding machine to inspection using TFM phased array

Specimens with intentionally embedded weld defects or flaws can be employed for training, development and research into procedures for mechanical property evaluation and structural integrity assessment. It is critical that the artificial defects are a realistic representation of the flaws produced by welding. Cylindrical holes, which are usually machined after welding, are not realistic enough for our purposes as it is known that they are easier to detect than the naturally occurring imperfections and cracks. Furthermore, it is usually impractical to machine a defect in a location similar to where the real weld defects are found. For example, electro-discharge machining can produce a through hole (cylindrical reflector) which neither represents the weld porosity (spherical voids) nor the weld crack (planar thin voids). In this study, the aim is to embed reflectors inside the weld intentionally, and then locate them using ultrasonic phased array imaging. The specimen is an 8 mm thick 080A15 Bright Drawn Steel plate of length 300 mm. Tungsten rods (ø2.4-3.2 mm & length 20-25 mm) and tungsten carbide balls (ø4 mm) will be used to serve as reflectors simulating defects within the weld itself. This study is aligned to a larger research project investigating multi-layer metal NDE found in many multi-pass welding and wire arc additive manufacturing (WAAM) applications and as such, there is no joint preparation as the first layer is deposited over the plate surface directly and subsequent layers contribute to the specimen build profile, similar to the WAAM samples. A tungsten inert gas welding torch mounted on a KUKA robot is used to deposit four layers for each weld, with our process using nine passes for the first layer, down to six passes for the last layer. During this procedure, the tungsten artificial reflectors are embedded in the weld, between the existing layers. The sample is then inspected by a 10 MHz ultrasonic phased array in direct contact with the sample surface using both conventional and total focusing method (TFM) imaging techniques. A phased array aperture of 32 elements has been used. The phased array controller is FIToolbox (Diagnostic Sonar, UK). Firstly, a focused B-scan has been performed with a range of settings for the transmit focal depth. Secondly, a full-aperture TFM method has been processed. All the reflectors of interest were detected successfully using this combination of B-scan and TFM imaging approaches

Taxcor w zapobieganiu restenozie : Polskie wieloośrodkowe badanie obserwacyjne oceniające skuteczność i bezpieczeństwo stentu Genius TAXCOR I

Wprowadzenie: Rejestr Taxcor PL był wieloośrodkowym, otwartym badaniem klinicznym fazy IV, w którym uczestniczyło 10 ośrodków akademickich w Polsce. Jego celem była ocena bezpieczeństwa i skuteczności stentu Genius TAXCOR I (Eurocor GmbH, Germany) uwalniającego paklitaksel w dawce 1 μg/mm2, implantowanego podczas przezskórnej angioplastyki wieńcowej (ang. percutaneous coronary intervention, PCI) ze wskazań planowych lub nagłych. Materiał i metody: Pacjenci włączani do badania stanowili grupę chorych kwalifikowanych do zabiegu PCI na podstawie dolegliwości klinicznych, wyników testów prowokacyjnych, u których w wykonanej angiografii tętnic wieńcowych potwierdzono obecność istotnego zwężenia (długość do 25 mm) w zakresie tętnic wieńcowych. Procedura implantacji stentu i postępowanie okołoi pozabiegowe były zgodne z obowiązującymi wytycznymi oraz lokalną praktyką ośrodków. Protokół badania nie ingerował w standardy leczenia pacjentów z rozpoznaniem choroby niedokrwiennej serca. Łączna liczba pacjentów analizowanych w rejestrze Taxcor PL wynosiła 100 osób zrekrutowanych w 10 ośrodkach w Polsce. Wyniki: Dane zgromadzone w trakcie badania dotyczą 100 zabiegów PCI w zakresie 110 leczonych zmian. Średni czas trwania zabiegu PCI wyniósł 43 min (SD 24), średnia średnica implantowanych stentów wyniosła 3,17 mm (SD 0,36), a średnia długość 20,5 mm (SD 5,82). Średni czas hospitalizacji pacjentów włączonych do badania to 2,5 doby (SD 3,4). W trakcie hospitalizacji u 2 pacjentów doszło do zamknięcia bocznicy podczas zabiegu PCI, czego następstwem był zawał mięśnia sercowego. U 3 pacjentów wystąpił krwiak w miejscu wkłucia, niewymagający interwencji chirurgicznej oraz przetoczenia preparatów krwi. W trakcie zabiegu PCI raportowano ponadto 3 przypadki dystalnej dysekcji (typu B, C i D). Poza tym nie obserwowano innych zdarzeń niepożądanych. W obserwacji 1-miesięcznej 1 pacjent miał wykonany planowy zabieg PCI w zakresie innego naczynia niż wcześniej leczone, będący kolejnym etapem rewaskularyzacji wieńcowej. Podobnie w obserwacji 3-miesięcznej u 1 z chorych wynikła konieczność wykonania zabiegu PCI na naczyniu nieleczonym implantacją stentu Taxcor. W 6-miesięcznej obserwacji (3.–6. miesiąc) zmarł 1 pacjent – był on hospitalizowany i operowany na oddziale chirurgicznym (hemikolektomia) z rozpoznaniem złośliwego guza przewodu pokarmowego i po 2 miesiącach zmarł z powodu niewydolności wielonarządowej. Pięciu pacjentów miało wykonany powtórny zabieg PCI w zakresie innych naczyń niż w momencie włączenia do badania. W 12-miesięcznej obserwacji (6.–12. miesiąc) 2 pacjentów miało wykonany powtórny zabieg PCI, w tym 1 w naczyniu leczonym w momencie włączenia do badania. Nieskuteczność zaopatrzenia naczynia docelowego (ang. target vessel failure, TVF) wystąpiła u 3 pacjentów [zgon z przyczyn wieńcowych – 0, zawał serca – 2, rewaskularyzacja zaopatrywanego naczynia (ponowna angioplastyka lub wszczepienie zespoleń omijających w zakresie zaopatrywanego naczynia) w ciągu 12-miesięcznego okresu obserwacji – 1]. Wnioski: Wyniki rejestru Taxcor PL dowodzą, że stent Genius Taxcor I jest bezpieczny w użyciu i zapewnia uzyskanie zadowalających wyników w obserwacji krótko- i długoterminowej, porównywalnych z innymi dostępnymi na rynku systemami stentów wieńcowych.Background: The Taxcor PL registry was a multicentre, phase IV open clinical trial, in which there participated 10 academic centres in Poland. Its aim was to assess the safety and effectiveness of the stent Genius TAXCOR I (Eurocor GmbH, Germany) at a dose of 1 μg/mm2 of paclitaxel, implanted during PCI with elective or urgent indications. Material and methods: Patients who entered the study were a group of patients qualified for PCI, based on clinical symptoms and provocative tests, in whom coronary angiography confirmed the presence of significant stenosis (length up to 25 mm) in the coronary arteries. Implantation procedure, peri- and postoperative procedure were in accordance with guidelines and local practice. The study protocol did not interfere with standard treatment for patients with a diagnosis of ischaemic heart disease. The total number of patients studied in the Taxcor PL registry is 100 people recruited in 10 centres in Poland. Results: Data were collected during the study on 100 PCIs (110 treated lesions). Average duration of PCI was 43 min (SD 24). Mean diameter of the implanted stent was 3.17 mm (SD 0.36) and the average length of 20.5 mm (SD 5.82). The mean time of hospitalization of patients enrolled in the study was 2.5 days (SD 3.4). During hospitalization, 2 patients experienced myocardial infarction which was the result of side branch closure during PCI. Three patients had a haematoma at the puncture site, which did not require surgical intervention and transfusion of blood products. During percutaneous coronary intervention also three cases of distal dissection were reported (type B, C and D). There were no other adverse events. In one-month follow-up one of the patients had a planned PCI procedure performed in another vessel than previously treated, which was the next stage of coronary revascularization. Similarly, in the 3-month follow-up one of the patients needed to undergo a PCI procedure on a vessel untreated with Taxcor. In the 6-month follow-up (3-6 months) one patient died – he was hospitalized with a diagnosis of malignant tumour and the gastrointestinal tract and operated on at the surgical ward (hemicolectomy); after 2 months of hospitalization, he died due to multiorgan failure. Five patients had a second percutaneous coronary intervention in other vessels than at the time of study enrolment. At 12-month follow-up (6-12 months) two patients had a second PCI procedure performed, including one in a vessel treated at the time of enrolment. Ineffectiveness of supply target vessel (called target vessel failure, TVF) occurred in three patients (death from coronary causes – 0, MI – 2, target vessel revascularization (TVR – PCI or CABG) during the 12-month observation period – 1. Conclusions: Taxcor PL registry results showed that the stent Genius Taxcor I is safe to use and provides satisfactory results in short- and long-term observation, in comparison with other commercially available coronary stent systems

Image-based monitoring for early detection of fouling in crystallisation processes

Fouling or encrustation is a significant problem in continuous crystallisation processes where crystal deposits at surfaces impede heat transfer, increase flow resistance and reduce product quality. This paper proposes an automatic algorithm to detect early stages of fouling using images of vessel surfaces from commodity cameras. Statistical analysis of the pixel intensity variation offers the ability to distinguish appearance of crystals in the bulk solution and on the crystalliser walls. This information is used to develop a fouling metric indicator and determine separately induction times for appearance of first crystals at the surfaces and in the bulk. A method to detect process state changes using Bayesian online change point detection is also proposed, where the first change point is used to determine induction time either at the surface or in the bulk, based on real-time online measurements without using any predetermined threshold which usually varies between experiments and depends on data acquisition equipment. This approach can be used for in situ monitoring of early signs of encrustation to allow early warning for corrective actions to be taken when operating continuous crystallisation processes

Renal artery sympathetic nerve radiofrequency denervation

Background: Arterial hypertension is one of the most common chronic diseases in the western world, affecting more than 25% of the adult population. Aim: The aim of this study was to assess changes in arterial blood pressure (BP) levels in hypertensive patients, after ablation of nerve terminals in renal arteries, using radiofrequency energy during 24 months of follow-up. Methods: Thirty-two patients with diagnosed resistant hypertension (20 men and 12 women) underwent percutaneous catheter-based renal denervation of nerve terminals in renal artery walls. Mean BP value before ablation was [mm Hg]: systolic 174.92, diastolic 99.73 and pulse pressure 75.19. After procedure reduction value of BP was reported [mm Hg]: systolic 146.78; diastolic 87.14, pulse pressure 59.64 at 24-month follow-up (p < 0.05 for all). Results: 30% of patients had systolic BP ≤ 140 mm Hg, 67% had diastolic BP ≤ 90 mm Hg, and optimum BP values ≤ 140/90 mm Hg were observed in 30% of patients. Conclusions: In our cohort of patients, percutaneous renal artery ablation procedure effectively reduces systolic, diastolic BP and pulse pressure. No adverse events during 24 months of follow-up were noted. These results were comparable with available data from SIMPLICITY I and II trials.Wstęp: Nadciśnienie tętnicze jest jedną z najbardziej powszechnych chorób przewlekłych w krajach zachodnich i dotyczy więcej niż 25% dorosłej populacji. Cel: Celem pracy była ocena zmian ciśnienia tętniczego (BP) u pacjentów z nadciśnieniem tętniczym po ablacji zakończeń nerwowych w tętnicach nerkowych z zastosowaniem prądu o wysokiej częstotliwości w 24-miesięcznej obserwacji. Metody: Trzydziestu dwóch pacjentów z rozpoznanym nadciśnieniem opornym (20 mężczyzn i 12 kobiet) poddano przezskórnej denerwacji zakończeń nerwowych w ścianie tętnic nerkowych. Średnia wartość ciśnienia krwi przed ablacją wynosiła [mm Hg]: 174,92 (skurczowe), 99,73 (rozkurczowe), a ciśnienie tętna — 75,19. Po 24 miesiącach obserwacji stwierdzono zmniejszenie wartości ciśnienia tętniczego [mm Hg]: skurczowe — 146,78; rozkurczowe — 87,14, ciśnienie tętna — 59,64. Wyniki: Wszystkie wyniki były statystycznie znamienne. U 30% pacjentów zanotowano wartość skurczowego BP ≤ 140 mm Hg, u 67% osób rozkurczowe BP wynosiło ≤ 90 mm Hg, natomiast optymalne wartości ciśnienia krwi (≤ 140/90 mm Hg) stwierdzono u 30% pacjentów po 24 miesiącach od ablacji tętnic nerkowych. Wnioski: W grupie badanych chorych przezskórna ablacja tętnicy nerkowej skutecznie obniżyła skurczowe i rozkurczowe BP oraz ciśnienia tętna. Nie stwierdzono istotnych zdarzeń niepożądanych w ciągu 24-miesięcznej obserwacji. Wyniki badań polskiej grupy pacjentów nie odbiegają w żaden sposób od wyników uzyskanymi w badaniach SIMPLICITY I i II