Digital image correlation in analysis of stiffness in local zones of welded joints

Ponašanje zavarenih spojeva u lokalnim zonama, kao i njihov uzajamni utjecaj, jedan je od glavnih problema u projektu zavarene konstrukcije. Naime, osnovni je problem u određivanju mehaničkih svojstava materijala u zavarenom spoju. Ta su svojstva neophodna za točan proračun zavarenih konstrukcija. Mogućnost dobivanja vrijednosti lokalne deformacije/pomaka čini tehniku "Digital Image Correlation" (DIC) pogodnom za ispitivanje zavarenog spoja i određivanje mehaničkih svojstava. Tijekom ovih ispitivanja za opterećenje je korišten uređaj za vlačnu provjeru, a dvije kamere su korištene za 3D analizu deformacije. Upotrijebljen je uzorak s paralelnim stranama dobiven zavarivanjem V spoja. Prije ispitivanja izvršeno je kalibriranje kako bi se dobili što točniji rezultati. U radu je predstavljena primjena DIC tehnike korištenjem Aramis softvera za mjerenje lokalnog pomaka/deformacije u zavarenom spoju. Dobiveni rezultati pokazuju da je zavareni spoj bio nejednako deformiran s prednje i zadnje strane korijena, u području elastične deformacije, tijekom vlačnog opterećenja. Zbog vlaka u uzorku s V-zavarom (osnovni materijal S235JRG2, žica elektrode - VAC 60), postoji uzajamni utjecaj mehaničkih svojstava lokalnih zona, gdje je krutost korijena zavara najviša.The behaviour of welded joints in local zones, as well as their mutual influence, represents one of the main challenges in welded structure design. Namely, the main issue lies in determining the mechanical properties of materials in a welded joint. These properties are necessary for an accurate calculation of welded structure integrity. The possibility of obtaining local strain/displacement values makes the "Digital Image Correlation" (DIC) technique suitable for welded joint testing and determining of mechanical properties. In this paper a tensile testing machine was used for loading and a two camera system was used for 3D strain analysis. A specimen with parallel sides, obtained by welding of a V joint was used. Calibration was performed prior to testing, in order to ensure dimensional consistency of the system. Application of DIC technique using Aramis software for measuring local displacement/strain in a welded joint is presented in this paper. Due to tension in the V-weld specimen (Base material - S235JRG2, electrode wire - VAC 60), mutual influence of mechanical properties of local zones is present, wherein the root weld had the highest stiffness

Benchmark problem definition and cross-validation for characteristic mode solvers

In October 2016, the Special Interest Group on Theory of Characteristic Modes (TCM) initiated a coordinated effort to perform benchmarking work for characteristic mode (CM) analysis. The primary purpose is to help improve the reliability and capability of existing CM solvers and to provide the means for validating future tools. Significant progress has already been made in this joint activity. In particular, this paper describes several benchmark problems that were defined and analyzes some results from the cross-validations of different CM solvers using these problems. The results show that despite differences in the implementation details, good agreement is observed in the calculated eigenvalues and eigencurrents across the solvers. Finally, it is concluded that future work should focus on understanding the impact of common parameters and output settings to further reduce variability in the results

LEAN THINKING IN HEALTHCARE: REVIEW OF IMPLEMENTATION RESULTS

For over decade, automotive industry originated lean concept has been successfully implemented in healthcare systems as a management method and philosophy with main focus on elimination of all types of wastes and looses in all tasks and processes so that time, materials, resources and medical procedures could be realized as effectively as it is possible. As main result lean concept implementation ensured to healthcare organizations to focus on their main core function and dedicate more time and efforts to patients without additional costs for them or healthcare system. However, lean implementation in healthcare could be much more difficult than in standard industrial environment and there are significant number of examples of lean in healthcare projects that failed to gain any measurable results and sustainable benefits from it. This paper presents review of some of the most successful implementations of lean tools and principles in healthcare organizations

Hard dental tissue minimal-invasive preparation using contemporary polymer rotating instruments and laser

Goal of contemporary dentistry is to decrease the patient's discomfort during treatment. Dentists aim to achieve maximum with the newly developed dental materials as well as with new cavity preparation techniques in the shortest time span. Since the development of the first constructed borer (drilling machine) for caries removal, the preparation techniques have considerably changed. The progress of dental materials as well as the cavity preparation techniques has led us to contemporary carbide tungsten and diamond borers that are used with obligatory water cooling. The innovation within this field represents newly developed polymer borers that can detect the difference between carious lesions and healthy tooth structure. In this way the cavity preparation may be performed without damaging dental healthy tissue. This is possible owing to their hardness which is lower than the hardness of intact dentin. Polymer borer preparation is painless with less vibration, while the increase in temperature is negligible. Lasers have been used in clinical dentistry since 1980s so it can be said that they represent a new technology. The function of lasers is based on ablation which requires water. Erbium lasers have shown the highest potential with their ability to produce effective ablation of hard dental tissues. Laser application in dentistry requires special training as well as some protective measures. Laser advantages, compared to traditional preparation techniques, involve the absence of vibration, painless preparation, possibility of preparation without anesthetic and easier patient's adjustment to dental intervention which is of importance, especially in pediatric dentistry.Savremena stomatologija teži ka što manjoj traumatizaciji pacijenta prilikom rada uz maksimalni učinak. Savremeni materijali uz nove vidove preparacije kaviteta pružaju mogućnost sanacije karijesnih lezija u najkraćem vremenskom roku. Vidovi preparacije kaviteta su se znatno promenili otkako je uvedeno prvo mašinski napravljeno svrdlo za uklanjanje karijesa. Tehnološki napredak materijala za ispune i načina preparacije doveli su do savremenih karbidnih i dijamantskih svrdla koja se koriste uz obavezno vodeno hlađenje. Inovaciju na polju rotirajućih instrumenata predstavljaju polimerna 'pametna' svrdla, koja uklanjaju karijesnu leziju bez mogućnosti povređivanja i uklanjanja zdrave zubne strukture. Ovo je moguće zahvaljujući čvrstoći koju poseduju, koja je manja od čvrstoće zdravog dentina. Zahvaljujući prirodi materijala od kojih su izrađena, ova svrdla omogućuju bezbolniji rad uz manje vibracija i slabije zagrevanje zubne supstance. Laseri su relativno novo tehnološko sredstvo u stomatologiji, a njihova klinička upotreba počela je osamdesetih godina dvadesetog veka. Laseri funkcionišu po principu ablacije, za šta je neophodno prisustvo vode. Najveći potencijal među ispitivanim laserima pokazali su erbijumski laseri, kojima je moguće uraditi efikasnu ablaciju čvrstih zubnih tkiva. Za korišćenje lasera u stomatologiji neophodni su posebna obuka i odgovarajuće mere zaštite. Prednosti lasera u poređenju sa drugim metodama preparacije čvrstih zubnih tkiva su nepostojanje vibracija, bezbolan rad, mogućnost rada bez anestezije i lakše prilagođavanje pacijenta stomatološkim intervencijama, što je veoma značajno u dečjoj stomatologiji

Catheter Ablation of Atrial Tachycardia after Pulmonary Vein Isolation in a Patient with Common Ostium of Inferior Pulmonary Veins: Case Report

Background and Objectives: Atrial fibrillation (AF), a prevalent cardiac arrhythmia, significantly impacts the quality of life of those affected. The preferred treatment for symptomatic AF, particularly when pharmacological methods fall short, is catheter ablation with pulmonary vein isolation (PVI). While common pulmonary vein (PV) anatomical variants, such as the right accessory pulmonary vein and the common ostium of left pulmonary veins (LCPV), have been studied extensively, their impact on the long-term outcome of PVI is known to be minimal. However, data on less common anomalies, like the common ostium of the left and right inferior pulmonary vein (CIPV), remain scarce in the medical literature. This report aims to shed light on the challenges and outcomes of catheter ablation in a patient with a rare CIPV anomaly. By presenting this case, we contribute to the limited knowledge about the management of such unique anatomical variations in AF treatment and discuss the importance of individualized treatment approaches. Case Presentation: We present a case involving a 56-year-old male diagnosed with AF in 2018. Initial PVI treatment was successful, but the patient experienced symptom recurrence after three years. A preprocedural CT scan before the second ablation revealed a CIPV anomaly. During the repeat procedure, a right superior pulmonary vein (RSPV) reisolation was performed due to identified gaps in the previous ablation line. Post-procedure, the patient maintained a sinus rhythm and reported no further symptoms. Conclusions: This case highlights the importance of recognizing rare PV anatomies like CIPV in the effective management of AF. Tailored ablation strategies, accounting for unique anatomical conditions, can lead to successful long-term outcomes, reinforcing the need for personalized approaches in AF treatment, especially in cases involving complex anatomical variations

Complex Hippocampal Response to Thermal Skin Injury and Protocols with Hyperbaric Oxygen Therapy and <i>Filipendula ulmaria</i> Extract in Rats

The aim of this study was to evaluate the alterations of the hippocampal function that may be related to anxiogenic response to thermal skin injury, including the morpho-functional alterations, and the effects of hyperbaric oxygen (HBO) and Filipendula ulmaria (FU) extract in the treatment of anxiety-like behavior that coincides with thermal skin injury. A rat thermal skin injury experimental model was performed on 2-month-old male Wistar albino rats. The evaluated therapeutic protocols included HBO and/or antioxidant supplementation. HBO was applied for 7 days in the hyperbaric chamber (100% O2, 2.5 ATA, 60 min). Oral administration of FU extract (final concentration of 100 mg/kg b.w.) to achieve antioxidant supplementation was also applied for 7 days. Anxiety level was estimated in the open field and elevated plus-maze test, which was followed by anesthesia, sacrifice, and collection of hippocampal tissue samples. HBO treatment and FU supplementation significantly abolished anxiogenic response to thermal skin injury. This beneficial effect was accompanied by the reduction in hippocampal pro-inflammatory and pro-apoptotic indicators, and enhanced BDNF and GABA-ARα2S gene expression, previously observed in untreated burns. The hippocampal relative gene expression of melatonin receptors and NPY positively responded to the applied protocols, in the same manner as µ and δ opioid receptors, while the opposite response was observed for κ receptors. The results of this study provide some confirmations that adjuvant strategies, such as HBO and antioxidant supplementation, may be simultaneously applied in the treatment of the anxiety-like behavior that coincides with thermal skin injury

Experimental Analysis of Handcart Pushing and Pulling Safety in an Industrial Environment by Using IoT Force and EMG Sensors: Relationship with Operators&rsquo; Psychological Status and Pain Syndromes

Non-ergonomic execution of repetitive physical tasks represents a major cause of work-related musculoskeletal disorders (WMSD). This study was focused on the pushing and pulling (P&amp;P) of an industrial handcart (which is a generic physical task present across many industries), with the aim to investigate the dependence of P&amp;P execution on the operators&rsquo; psychological status and the presence of pain syndromes of the upper limbs and spine. The developed acquisition system integrated two three-axis force sensors (placed on the left and right arm) and six electromyography (EMG) electrodes (placed on the chest, back, and hand flexor muscles). The conducted experiment involved two groups of participants (with and without increased psychological scores and pain syndromes). Ten force parameters (for both left and right side), one EMG parameter (for three different muscles, both left and right side), and two time-domain parameters were extracted from the acquired signals. Data analysis showed intergroup differences in the examined parameters, especially in force integral values and EMG mean absolute values. To the best of our knowledge, this is the first study that evaluated the composite effects of pain syndromes, spine mobility, and psychological status of the participants on the execution of P&amp;P tasks&mdash;concluding that they have a significant impact on the P&amp;P task execution and potentially on the risk of WMSD. The future work will be directed towards the development of a personalized risk assessment system by considering more muscle groups, supplementary data derived from operators&rsquo; poses (extracted with computer vision algorithms), and cognitive parameters (extracted with EEG sensors)

Simultaneous Administration of Hyperbaric Oxygen Therapy and Antioxidant Supplementation with <i>Filipendula ulmaria</i> Extract in the Treatment of Thermal Skin Injuries Alters Nociceptive Signalling and Wound Healing

Background and Objectives: Thermal skin injuries are a prevalent cause of skin damage, potentially leading to severe morbidity and significant mortality. In this study, we intended to estimate the effects of HBO (hyperbaric oxygen treatment) and antioxidant supplementation with Filipendula ulmaria extract, individually and simultaneously, in the treatment of thermal skin injuries. Materials and Methods: As a thermal skin injury experimental model, we used two-month-old male Wistar albino rats. Thermal injuries were made with a solid aluminium bar at a constant temperature of 75 °C for 15 s. Hyperbaric oxygen treatment was performed in a specially constructed hyperbaric chamber for rats (HYB-C 300) for seven consecutive days (100% O2 at 2.5 ATA for 60 min). Antioxidant supplementation was performed with oral administration of Filipendula ulmaria extract dissolved in tap water to reach a final concentration of 100 mg/kg b.w. for seven consecutive days. Results: Simultaneous administration of hyperbaric oxygen therapy and antioxidant supplementation with Filipendula ulmaria extract significantly ameliorated the macroscopic and histopathological characteristics of the wound area and healing. Also, this therapeutic approach decreased the local expression of genes for proinflammatory mediators and increased the expression of the μ-opioid receptor and the MT1 and MT2 receptors in the wound area and spinal cord, with a consequent increase in reaction times in behavioural testing. Conclusions: In conclusion, the presented results of our study allow evidence for the advantages of the simultaneous employment of HBO and antioxidant supplementation in the treatment of thermal skin injuries, with special reference to the attenuation of painful sensations accompanied by this type of trauma

The Enhanced Effects of Swimming and Running Preconditioning in an Experimental Model of Myocardial Ischemia/Reperfusion Injury

Background and Objectives: This study was conducted to examine the influence of different swimming and running protocols as forms of physiological preconditioning on an isolated rat heart’s ischemia/reperfusion injury. Materials and Methods: This study was conducted on 60 male Wistar albino rats (6 weeks old, bw: 200 ± 20 g), divided into: CTRL group—a sedentary control group; sAeT—a group that underwent aerobic swimming conditioning using a swimming protocol for 8 weeks; sAnT—a group that underwent anaerobic swimming conditioning; rAeT—a group that underwent aerobic running conditioning; and rAnT—a group that underwent anaerobic running conditioning. After the preconditioning protocols, ex vivo estimating of myocardial function according to the Langendorff technique was performed. Results: The anaerobic running training decreased heart rate and the anaerobic swimming training reduced coronary flow, demonstrating the difference in the physiological heart response of aerobic/anaerobic physical training (p p p Conclusions: The data from this experimental study support many protective training effects, i.e., improved contractility, improved resting heart rate, and increased physical work capacity and exercise tolerance. Physical training in the form of anaerobic running induces greater heart preconditioning for reperfusion injury in comparison with anaerobic swimming training

Hepcidin Is a Reliable Marker of Iron Deficiency Anemia in Newly Diagnosed Patients with Inflammatory Bowel Disease

Background and Aim. Differentiating iron deficiency anemia (IDA) from anemia of chronic disease (ACD) in patients with inflammatory bowel disease (IBD) represents a clinical challenge. Hepcidin is a polypeptide synthetized in the liver, and iron levels or inflammation mostly regulate hepcidin production. Our aim was to determine serum hepcidin levels in patients with inflammatory bowel disease (IBD) as well to investigate whether hepcidin levels correlate with disease activity. Material and Methods. A case-control study was preformed among newly diagnosed IBD patients and same number age- and sex-matched healthy controls. All patients underwent a total ileocolonoscopy. Complete blood count was obtained in addition to inflammatory markers (CRP, erythrocyte sedimentation rate-ESR). Serum levels of hepcidin were determined with commercially available enzyme-linked immunosorbent assay (DRG Instruments Marburg, Germany). Serum iron, TIBC, and UIBC were assessed with an electrochemiluminesence immunoassay, and soluble transferrin receptor (sTfR) was assessed using an immunoturbidimetric method. Mayo score and CDAI, respectively, were calculated for each patient. Statistical analyses were performed using the SPSS software version 20.0 for Windows. Results. There was a high statistically significant difference between IBD patients and controls in levels of hepcidin (P0.05). However, we have found a statistically significant negative correlation of sTfR and TIBC with hepcidin (P<0.01). Conclusion. Results of our study suggest that hepcidin is a reliable marker of IDA in patients with IBD, and it could be used in routine clinical practice when determining adequate therapy in these patients