Analysis of Paint Flow Pulsations during High-Speed Rotary Bell Atomization

High-speed rotary bell atomization is the preeminent coating technique in the automotive industry. It is widely accepted that a narrow droplet size distribution and constant spray are necessary in order to guarantee uniform film thickness and high-quality appearance. This may be deteriorated by paint flow pulsations. So far, however, no studies exist regarding such fluctuations quantitatively for this type of atomizers. We fill this gap using image analysis of high-speed recordings close to the bell edge. We could show that the fundamental pulsation frequency increases linearly with rotational speed. A ratio of pulsation frequency and true rotational speed of about 3 was found, indicating that pulsations were initiated mainly by the three struts of the distributor disc. The coefficient of variation, i.e., the amplitude of fluctuation increased with decreasing liquid volume rate and rotational speed. Beyond that, we could show that the formation of droplets larger than 100 μm, which are assumed to cause paint defects, is promoted by the degree of fluctuation. These findings may stimulate development of bell cups showing less paint flow pulsations

Percutaneous Anorectoplasty (PARP)-An Adaptable, Minimal-Invasive Technique for Anorectal Malformation Repair

Background: Anorectal malformations comprise a broad spectrum of disease. We developed a percutaneous anorectoplasty (PARP) technique as a minimal-invasive option for repair of amenable types of lesions. Methods: Patients who underwent PARP at five institutions from 2008 through 2021 were retrospectively analyzed. Demographic information, details of the operative procedure, and perioperative complications and outcomes were collected. Results: A total of 10 patients underwent the PARP procedure during the study interval. Patients either had low perineal malformations or no appreciable fistula. Most procedures were guided by ultrasound, fluoroscopy, or endoscopy. Median age at PARP was 3 days (range 1 to 311) days;eight patients were male. Only one intraoperative complication occurred, prompting conversion to posterior sagittal anorectoplasty. Functional outcomes in most children were highly satisfactory in terms of continence and functionality. Conclusions: The PARP technique is an excellent minimal-invasive alternative for boys born with perineal fistulae, as well as patients of both sexes without fistulae. The optimal type of guidance (ultrasound, fluoroscopy, or endoscopy) depends on the anatomy of the lesion and the presence of a colostomy at the time of repair

A case report of laparoscopic duodenal atresia repair in a neonate using a novel miniature stapling device

Introduction: Laparoscopic duodenal atresia repair is an advanced procedure performed in select pediatric surgical centers. Recently, sub–6 mm endosurgical staplers have been introduced, facilitating and accelerating the creation of intracorporeal intestinal anastomoses. Presentation of case: We performed a laparoscopic duodenojejunostomy in a one-day-old child with duodenal atresia due to annular pancreas using a novel 5.8 mm articulating endostapler with excellent outcome. The technical details are reported. Discussion: Laparoscopic duodenojejunostomy is a technically demanding procedure due to difficulty in hand-sewn anastomosis in a small and restricted space. With this novel 5.8 mm articulating endostapler, we were able to perform a quicker and easier anastomosis. Conclusion: We report a case of laparoscopic duodenal atresia repair in a neonate using a novel miniature stapling device. This new technique is a safe, quick and easier way to perform laparoscopic duodenal atresia repair

Analysis of paint flow pulsations during high-speed rotary bell atomization

High-speed rotary bell atomization is the preeminent coating technique in the automotive industry. It is widely accepted that a narrow droplet size distribution and constant spray are necessary in order to guarantee uniform film thickness and high-quality appearance. This may be deteriorated by paint flow pulsations. So far, however, no studies exist regarding such fluctuations quantitatively for this type of atomizers. We fill this gap using image analysis of high-speed recordings close to the bell edge. We could show that the fundamental pulsation frequency increases linearly with rotational speed. A ratio of pulsation frequency and true rotational speed of about 3 was found, indicating that pulsations were initiated mainly by the three struts of the distributor disc. The coefficient of variation, i.e., the amplitude of fluctuation increased with decreasing liquid volume rate and rotational speed. Beyond that, we could show that the formation of droplets larger than 100 μm, which are assumed to cause paint defects, is promoted by the degree of fluctuation. These findings may stimulate development of bell cups showing less paint flow pulsations

Central venous access devices (CVAD) in pediatric oncology patients : a single-center retrospective study over more than 9 years

Central venous access devices (CVAD) provide important benefits in the management of oncological pediatric patients. However, these catheters are responsible for severe complications. Methods: In this context, we aimed to analyze all patients receiving a CVAD in the Department of Pediatric Hematology and Oncology of the University hospital of Mainz over a period of 9 years, focused on CVAD related complications. Data on demographics, as well as intraoperative and postoperative complications were extracted. Results: A total of 296 patients with a mean age 93.2 ± 62.4 months were analyzed. The majority suffered from leukemia (n = 91, 30.7%), lymphomas (n = 50, 16.9%), and brain tumors (n = 48, 16.2%). In 63 (21.3) patients, complications were observed. No death caused by complications of CVADs was found in our series. Catheter-related blood stream infections (BSI) (7.4%) were most prevalent, followed by dislodgements (5.4%), occlusions (2.7%), thrombosis (2.4%), and catheter leakage (2.4%). Insertion site infections were observed in three patients (1.0%). Fifty-nine percent of all patients with catheter-related BSI suffered from Leukemia. In patients with Catheter-related BSIs we detected the condition leukemia as the underlying disease as a risk factor compared to solid tumors as the underlying disease. Overall, totally implanted devices (ports) have a lower complication rate than tunneled catheter. Conclusion: Implantation of CVADs seems to be safe and reliable in this large pediatric patient cohort. Even if complications occur in the long-term management of CVADs, they can be treated successfully and long-term catheter survival rates are excellent

Multiphoton microscopy in the diagnostic assessment of pediatric solid tissue in comparison to conventional histopathology : results of the first international online interobserver trial

Purpose: Clear resection margins are paramount for good outcome in children undergoing solid tumor resections. Multiphoton microscopy (MPM) can provide high-resolution, real-time, intraoperative microscopic images of tumor tissue. Objective: This prospective international multicenter study evaluates the diagnostic accuracy, feasibility, and interobserver congruence of MPM in diagnosing solid pediatric tissue and tumors for the first time. Material and methods: Representative fresh sections from six different neonatal solid tissues (liver, lung, kidney, adrenal gland, heart muscle, testicle) and two types of typical pediatric solid tumors (neuroblastoma, rhabdomyosarcoma) with adjacent nonneoplastic tissue were imaged with MPM and then presented online with corresponding H&E stained slides of the exact same tissue region. Both image sets of each tissue type were interpreted by 38 randomly selected international attending pediatric pathologists via an online evaluation software. Results: The quality of MPM was sufficient to make the diagnosis of all normal tissue types except cardiac muscle in >94% of assessors with high interobserver congruence and 95% sensitivity. Heart muscle was interpreted as skeletal muscle in 55% of cases. Based on MPM imaging, participating pathologists diagnosed the presented pediatric neoplasms with 100% specificity, although the sensitivity reached only about 50%. Conclusion: Even without prior training, pathologists are able to diagnose normal pediatric tissues with valuable accuracy using MPM. While current MPM imaging protocols are not yet sensitive enough to reliably rule out neuroblastoma or rhabdomyosarcoma, they seem to be specific and therefore useful to confirm a diagnosis intraoperatively. We are confident that improved algorithms, specific training, and more experience with the method will make MPM a valuable future alternative to frozen section analysis

Reply to Peña, A. Comment on “Küppers et al. Percutaneous Anorectoplasty (PARP)—An Adaptable, Minimal-Invasive Technique for Anorectal Malformation Repair. <i>Children</i> 2022, <i>9</i>, 587”

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Ultrafein-eutektische Ti-basierte Legierungen für die additive Fertigung

Wir entwickeln zurzeit neuartige hochfeste Legierungen mit ultrafeinen eutektischen Mikrostrukturen für die additive Fertigung (AM), um die Leistungsfähigkeit von Verdichterrädern zu steigern. Duch die hohen Erstarrungs- und Abkühlraten bei AM, und besonders beim selektiven Laserschmelzen (SLM), können erhebliche kornfeinungsbedingte Festigkeitssteigerungen erreicht werden. Im Rahmen der Materialentwicklung wurden mehrere Ti-basierte eutektische und hypoeutektische Legierungen (Ti-32Fe, Ti-28Fe-9Sn-5Nb, Ti-26Fe-4Sn-2.5Nb and Ti-21Fe-7Sn-4Nb, Gew.-%) mit SLM verarbeitet. Dabei wurden sowohl Probekörper für metallographische und werkstoffmechanische Untersuchungen, als auch Verdichteräder als Demonstratoren hergestellt. Die Mikrostrukturen wurden insbesondere mit Synchrotron Röntgenbeugung (SXRD), Rasterelektronenmikroskopie (REM) und ptychographischer Röntgencomputertomographie (PXCT) charakterisiert. In-situ-Druckversuche wurden in einem Umformdilatometer, bei gleichzeitiger Durchstrahlung des Prüfbereiches mit hochenergetischer Röntgenstrahlung durchgeführt, um mittels SXRD die Umformechanismen bei Raumtemperatur, 300 °C, 450 °C und 600 °C zu untersuchen. Bei deutlich erhöhten Bauraumtemperaturen konnten rissfreie Proben aller untersuchter Legierungen hergestellt werden. Die Materialien wiesen, je nach Legierungszusammensetzung, Vorwärmtemperatur und Laserparameter, mehrphasige Mikrostrukturen auf, mit Bestandteilen unterschiedlicher Längenskalen, welche teilweise als Dendriten oder lamellare Strukturen vorlagen. Die Druckversuche zeigten, dass Festigkeiten über 2000 MPa erreicht werden können. Insbesondere bei erhöhten Temperaturen ist plastische Verformung mit Bruchdehungen über 10% nachweisbar. Ti-basierte ultrafeine eutektische Legierungen können somit bei stark erhöhten Vorheiztemperaturen mittels SLM verarbeitet werden. Allerdings muss sehr auf eine hochreine Schutzgasatmosphäre geachtet werden, um Sauerstoffaufnahme und Materialversprödung zu vermeiden