Effect of Cooling Rate on Microstructure of In Situ TiC-Reinforced Composite Surface Layers Synthesized on Ductile Cast Iron by Laser Alloying.

The microstructure of the in situ TiC-reinforced composite surface layers developed during laser surface alloying of a ductile cast iron substrate with titanium was related to the solidification conditions in the molten pool. The solidification conditions were estimated using infrared thermography. It was found that the cooling rates of the melt up to about 700 °C/s enable the complete reaction between carbon and the entire amount of titanium introduced into the molten pool. In turn, the cooling rate of about 280 °C/s for the melt containing 8.0 wt% Ti allows the TiC particles to grow in the dendritic form with well-developed secondary arms and a total size of up to 30 µm. For a constant Ti content, the cooling rate of the melt had no effect on the TiC fraction. The increase in the cooling rate elevated the retained austenite fraction in the matrix material, lowering its hardness.

Mortality and major postoperative complications within 1 year after vascular surgery: a prospective cohort study.

INTRODUCTION: Patients undergoing vascular procedures are prone to developing postoperative complications affecting their short­term mortality. Prospective reports describing the incidence of long­term complications after vascular surgery are lacking. OBJECTIVES: We aimed to describe the incidence of complications 1 year after vascular surgery and to evaluate an association between myocardial injury after noncardiac surgery (MINS) and 1­year mortality. PATIENTS AND METHODS: This is a substudy of a large prospective cohort study Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION). Recruitment took place in 28 centers across 14 countries from August 2007 to November 2013. We enrolled patients aged 45 years or older undergoing vascular surgery, receiving general or regional anesthesia, and hospitalized for at least 1 night postoperatively. Plasma cardiac troponin T concentration was measured before the surgery and on the first, second, and third postoperative day. The patients or their relatives were contacted 1 year after the procedure to assess the incidence of major postoperative complications. RESULTS: We enrolled 2641 patients who underwent vascular surgery, 2534 (95.9%) of whom completed 1­year follow­up. Their mean (SD) age was 68.2 (9.8) years, and the cohort was predominantly male (77.5%). The most frequent 1­year complications were myocardial infarction (224/2534, 8.8%), amputation (187/2534, 7.4%), and congestive heart failure (67/2534, 2.6%). The 1­year mortality rate was 8.8% (223/2534). MINS occurred in 633 patients (24%) and was associated with an increased 1­year mortality (hazard ratio, 2.82; 95% CI, 2.14-3.72; P <0.001). CONCLUSIONS: The incidence of major postoperative complications after vascular surgery is high. The occurrence of MINS is associated with a nearly 3­fold increase in 1­year mortality.

The effect of TIG welding on the structure and hardness of butt joints made of Inconel 718.

The tests discussed in the article aimed to analyse the structure and hardness of the heat affected zone and that of the weld in thin butt joints (1.0 mm) made of Inconel 718 using the TIG method and variable welding linear energy restricted within the range of 45 J/mm to 80 J/mm. The test joints were subjected to visual tests, macro and microscopic metallographic tests, scanning electron microscopy-based structural observations and hardness measurements. The tests concerned with the effect of the TIG welding of butt joints made of 1.0 mm thick sheets (Inconel 718) in laboratory conditions revealed that the most favourable quality of the sheets was obtained when welding arc linear energy was restricted within the range of approximately 45 J/mm to 80 J/mm. An increase in linear energy within the above-presented range led to an increase in the width of the weld and that of the HAZ (observed in the joints subjected to macroscopic metallographic tests). In addition, an increase in linear energy restricted within the aforesaid range increased the grain size in matrix γ (in the HAZ) from approximately 10 µm-20 µm. The structure of the weld contained the zone of columnar grains oriented towards the fusion line as well as large groups of primary grains having the dendritic structure with clearly visible axes of primary dendrites of varied orientation. In addition, the weld structure also contained precipitates in the form of low-melting eutectics located in interdendritic spaces.

Dynamic Range Compression of Thermograms for Assessment of Welded Joint Face Quality.

Temperature is one of the essential parameters in fusion welding. Typically, an uncooled infrared detector acquires 14-bit data, while a human observer can only distinguish about 128 levels of grey. For IR HDR (high dynamic range) images, one of the main goals of dynamic range compression is to enhance the visibility of low-contrast details. It is an important issue because the temperature span in the cross-section of a welded joint and its length are large. In the paper, global approaches for range compression are investigated, such as algorithms that include pixel transformations, histogram equalization ('he') and some of its variants. Additionally, multiscale decomposition methods were investigated. All results are obtained for the sequences of thermograms acquired during the TIG welding of plates made of Inconel 625 superalloy. The process was observed with an uncooled IR camera. The application of compression methods led to the generation of low-dynamic-range (LDR) IR images. The algorithms allowed the preservation of global contrast and enhancement of the visibility of hot details in dark and low-contrast areas. All IR representations of the welded samples were evaluated, and relationships between apparent temperature counted in the pixel-level value and weld-face geometry were revealed. Methods based on wavelet transforms were found to be the most suitable for this type of image; nevertheless, a relatively large local noise was generated.

The Structure and Properties of Laser-Cladded Inconel 625/TiC Composite Coatings.

This article presents production results concerning metal matrix composite-coatings made using the laser-cladding technology. The enhancement of the wear resistance of the material surface is the one of the main goals accompanying the manufacturing of composite coatings. Nickel-based superalloys are used in several industries because they are characterized by a number of desirable properties including high tensile and fatigue strength as well as resistance to high-temperature corrosion in aggressive environments. One of the most interesting materials from the group of superalloys is Inconel 625, used as a matrix material in tests discussed in this article. However, nickel-based superalloys are also characterized by an insufficient wear resistance of the surface, therefore, in relation to the tests discussed in this article, Inconel 625-based composite coatings were reinforced by adding 10%, 20% and 40% of titanium carbide particles. The addition of hard phases, i.e., TiC, WC or SiC particles can have a positive effect on the erosion resistance of cladded specimens. The aim of the experiment was to determine the impact of the titanium carbide content on the structure of the alloy and its resistance to corrosive wear, enabling the extension of the service life of Inconel 625/TiC composite coatings. The investigation included microhardness tests, corrosion resistance analysis, penetrant tests, macrostructure and microstructure analyses and X-ray diffraction (XRD) tests. The TiC particles increased the hardness of the coatings and, in general, had a negative impact on the corrosion resistance of pure Inconel 625 coatings. However, the increased homogeneity of composite coatings translated into the improvement of corrosion resistance.

Assessment of the Laser Beam Welding of Galvanized Car Body Steel with an Additional Organic Protective Layer.

This study discusses the effect of laser beam welding parameters on the structure, mechanical properties and corrosion resistance of 1.2 mm thick galvanized sheets made of low-carbon steel DC04 provided with a ZE36/36 GardoprotectOC2BU organic coating. The test laser beam butt welded joints were made without the filler metal, using a variable welding rate, where linear welding energy was restricted within the range of 30 J/mm to 90 J/mm. The joints were subjected to non-destructive tests, destructive tests and corrosion resistance tests. The tests revealed the possibility of making joints meeting the criteria specified in the ISO 15614-11 standard. Regardless of the value of linear welding energy applied in the process, all the joints were characterised by high mechanical and plastic properties. It was noticed that an increase in linear welding energy from 30 J/mm to 90 J/mm was accompanied by the widening of the weld and that of the heat-affected zone (HAZ). In addition, an increase in linear welding energy was accompanied by a decrease in the maximum weld hardness to approximately 250 HV0.2. In the HAZ, hardness was restricted within the range of 190 HV0.2 to 230 HV0.2 and decreased along with increasing linear welding energy. In the static tensile test, regardless of the value of linear welding energy, the test specimen ruptured in the base material. In the bend test, regardless of the value of linear welding energy, a bend angle of 180° was obtained without partial tear or scratches; unit elongation was restricted within the range of 29% to 42%. The electrochemical tests and experiments performed in the salt spray chamber revealed the very high effectiveness of the corrosion protections against aggressive chloride ions.

Treatment outcomes in Polish COVID-19 patients requiring hospitalisation in the intensive care unit: a single-centre retrospective study.

INTRODUCTION: COVID-19 has disturbed the functioning of Polish healthcare for the past two years. Due to the high proportion of patients requiring admission to the intensive care unit (ICU), these wards are particularly overwhelmed and are considered the bottleneck of the healthcare system. The aim of this study was to describe clinical outcomes of critically ill patients treated in a single tertiary ICU in Poland, assess factors associated with mortality and compare outcomes of patients treated during the 2nd and 3rd waves of the pandemic. MATERIAL AND METHODS: This is a retrospective single-centre study including patients admitted to the ICU between October 2020 and May 2021 (the 3rd wave) with confirmed SARS-CoV-2 infection. Patients were followed up until death or 90 days after ICU admission. The co-primary endpoints of this study included ICU, 30-day and 90-day mortality. RESULTS: We enrolled 108 patients at a mean age of 64.3 (SD = 12) years, the majority of whom were male (63.9%). Mortality in the ICU, after 30 days and 90 days was 44.4% (48/108), 50.0% (54/108), and 57.9% (62/108), respectively. Mortality at 90 days was associated with increasing age (OR = 3.97, 95% CI: 1.87-8.41) and was significantly higher during the 2nd wave (65.6 vs. 46.5%, log-rank P = 0.043) compared to the 3rd wave of the pandemic. CONCLUSIONS: This retrospective single-centre study confirms the high mortality rate among critically ill patients with COVID-19. Moreover, it suggests a significant association between 90-day mortality and increasing age as well as differences in mortality between the 2nd and 3rd waves of the pandemic in Poland.

Short-term mortality of patients ≥80 years old admitted to European intensive care units: an international observational study.

BACKGROUND: Limited evidence suggests variation in mortality of older critically ill adults across Europe. We aimed to investigate regional differences in mortality among very old ICU patients. METHODS: Multilevel analysis of two international prospective cohort studies. We included patients ≥80 yr old from 322 ICUs located in 16 European countries. The primary outcome was mortality within 30 days from admission to the ICU. Results are presented as n (%) with 95% confidence intervals and odds ratios (ORs). RESULTS: Of 8457 patients, 2944 (36.9% [35.9-38.0%]) died within 30 days. Crude mortality rates varied widely between participating countries (from 10.1% [6.4-15.6%] to 45.1% [41.1-49.2%] in the ICU and from 21.3% [16.3-28.9%] to 55.3% [51.1-59.5%] within 30 days). After adjustment for confounding variables, the variation in 30-day mortality between countries was substantially smaller than between ICUs (median OR 1.14 vs 1.58). Healthcare expenditure per capita (OR=0.84 per $1000 [0.75-0.94]) and social health insurance framework (OR=1.43 [1.01-2.01]) were associated with ICU mortality, but the direction and magnitude of these relationships was uncertain in 30-day follow-up. Volume of admissions was associated with lower mortality both in the ICU (OR=0.81 per 1000 annual ICU admissions [0.71-0.94]) and in 30-day follow-up (OR=0.86 [0.76-0.97]). CONCLUSION: The apparent variation in short-term mortality rates of older adults hospitalised in ICUs across Europe can be largely attributed to differences in the clinical profile of patients admitted. The volume-outcome relationship identified in this population requires further investigation.

Prognostic value of preoperative electrocardiography in predicting myocardial injury after vascular surgery.

BACKGROUND: The current European guidelines recommend that a preoperative electrocardiogram (ECG) should be performed routinely in patients scheduled for high-risk surgery. However, the evidence regarding ECG as a predictor of perioperative cardiac complications is weak. AIM: To evaluate the association of preoperative ECG with short- and long-term outcomes in patients undergoing high-risk vascular procedures. METHODS: This was a substudy of the international Vascular events In noncardiac Surgery patIents cohort evaluatioN (VISION) Study and included consecutive patients undergoing vascular procedures in a single tertiary center. In each patient, a preoperative 12-lead ECG was evaluated by two experienced clinicians following the Polish Cardiac Society recommendations. We performed routine perioperative troponin monitoring at five time points (one preoperative and four postoperative measurements) to evaluate whether preoperative ECG abnormalities are associated with myocardial injury after noncardiac surgery (MINS) and 1-year major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, and stroke. RESULTS: The study group comprised 348 patients, 80.5% of whom were male and the median age (interquartile range [IQR]) was 65 (59-72) years. The incidence of MINS and 1-year MACE was 18.7% and 14.4%, respectively. Multivariable analysis showed that none of the predefined ECG abnormalities (ST depression, left axis deviation, atrial fibrillation, and bundle branch block) was associated with the incidence of MINS or 1-year MACE. CONCLUSION: This study confirmed that preoperative ECG abnormalities are frequent in patients undergoing high-risk vascular surgery. However, we did not find evidence supporting the relation between preoperative ECG abnormalities and postoperative adverse cardiac outcomes in high-risk patients.

High-Power Diode Laser Surface Transformation Hardening of Ferrous Alloys.

A high-power direct diode laser (HPDDL) having a rectangular beam with a top-hat intensity distribution was used to produce surface-hardened layers on a ferrous alloy. The thermal conditions in the hardened zone were estimated by using numerical simulations and infrared (IR) thermography and then referred to the thickness and microstructure of the hardened layers. The microstructural characteristics of the hardened layers were investigated using optical, scanning electron and transmission electron microscopy together with X-ray diffraction. It was found that the major factor that controls the thickness of the hardened layer is laser power density, which determines the optimal range of the traverse speed, and in consequence the temperature distribution in the hardened zone. The increase in the cooling rate led to the suppression of the martensitic transformation and a decrease in the hardened layer hardness. The precipitation of the nanometric plate-like and spherical cementite was observed throughout the hardened layer.

FEM-Based Thermogram Correction for Inconel 625 Joint Hardness Clustering.

Assessing the temperature of the joint in on-line mode is a vital task that is demanded to characterize the formations of terns formations that are taking place in a joint and result in reaching necessary properties of the joint. Arc welding generates a high amount of heat that is reflected by the metallic surface of the welded object. In the paper, a temperature measurement credibility increase method is described and evaluated. The proposed method is used to reduce the influence of the reflected temperature of the hot torch and the arc on the temperature distribution observed on the surface of the welded joint using an infrared camera. The elaborated approach is based on comparison between infrared observation of the solidifying weld and precisely performed finite element method (FEM) simulation. The FEM simulations were calibrated according to the geometry of the fusion zone. It allows to precisely model heat source properties. The best-reflected temperature correction map was selected and applied to obtain a temperature representation that differs from the FEM baseline by less than 10 °C. Precise temperature values allowed us to cluster welded joints in 3D feature space (temperature, hardness, linear energy). It was found that by using the k-means clustering method it is possible to distinguish between correct and faulty (in terms of too low mechanical properties) joints.

Relationship between the Clinical Frailty Scale and short-term mortality in patients ≥ 80 years old acutely admitted to the ICU: a prospective cohort study.

BACKGROUND: The Clinical Frailty Scale (CFS) is frequently used to measure frailty in critically ill adults. There is wide variation in the approach to analysing the relationship between the CFS score and mortality after admission to the ICU. This study aimed to evaluate the influence of modelling approach on the association between the CFS score and short-term mortality and quantify the prognostic value of frailty in this context. METHODS: We analysed data from two multicentre prospective cohort studies which enrolled intensive care unit patients ≥ 80 years old in 26 countries. The primary outcome was mortality within 30-days from admission to the ICU. Logistic regression models for both ICU and 30-day mortality included the CFS score as either a categorical, continuous or dichotomous variable and were adjusted for patient's age, sex, reason for admission to the ICU, and admission Sequential Organ Failure Assessment score. RESULTS: The median age in the sample of 7487 consecutive patients was 84 years (IQR 81-87). The highest fraction of new prognostic information from frailty in the context of 30-day mortality was observed when the CFS score was treated as either a categorical variable using all original levels of frailty or a nonlinear continuous variable and was equal to 9% using these modelling approaches (p < 0.001). The relationship between the CFS score and mortality was nonlinear (p < 0.01). CONCLUSION: Knowledge about a patient's frailty status adds a substantial amount of new prognostic information at the moment of admission to the ICU. Arbitrary simplification of the CFS score into fewer groups than originally intended leads to a loss of information and should be avoided. Trial registration NCT03134807 (VIP1), NCT03370692 (VIP2).

Assessment of Airway Remodeling Using Endobronchial Ultrasound in Asthma-COPD Overlap.

PURPOSE: The aim of this study was to evaluate the structural changes of the airways using the endobronchial ultrasound (EBUS) in ACO patients compared to severe asthma and COPD patients. PATIENTS AND METHODS: The study included 17 patients with ACO, 17 patients with COPD and 33 patients with severe asthma. Detailed clinical data were obtained from all participants. Basic laboratory tests were performed, including measurement of eosinophil counts in blood and serum immunoglobulin E (IgE) concentrations. All patients underwent spirometry and bronchoscopy with EBUS (a 20­MHz ultrasound probe) to measure the total thicknesses of the bronchial walls and their particular layers in segmental bronchi of the right lower lobe. EBUS allows to distinguish five layers of the bronchial wall. Layer 1 (L1) and layer 2 (L2) were analyzed separately, while the outer layers (layers 3-5 [L3-5]) that correspond to cartilage were assessed together. RESULTS: In patients with ACO the thicknesses of the L1 and L2 layers, which are mainly responsible for remodeling, were significantly greater than in patients with COPD and significantly smaller than in patients with severe asthma (median L1= 0.17 mm vs 0.16 mm vs 0.18 mm, p<0.001; median L2= 0.18 mm vs 0.17 mm vs 0.20 mm, p<0.001, respectively). The thicknesses of the total bronchial walls (L1+L2+L3-5) and L3-5 were significantly smaller in ACO and COPD patients compared to asthma patients (median L1+L2+L3-5= 1.2 mm vs 1.14 mm vs 1.31 mm, p<0.001; median L3-5= 0.85 mm vs, 0.81 mm vs 0.92 mm, p=0.001, respectively). CONCLUSION: The process of structural changes in the airways assessed by EBUS is more advanced in individuals with ACO compared to patients with COPD, and less pronounced compared to patients with severe asthma. It seems that EBUS may provide useful information about differences in airway remodeling between ACO, COPD and severe asthma.

A clinical profile and factors associated with severity of the disease among Polish patients hospitalized due to COVID-19 - an observational study.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) is one of the greatest clinical challenges of the last decades. Clinical factors associated with severity of the disease remain unclear. The aim of the study was to characterize Polish patients hospitalized due to COVID-19 and to evaluate potential prognostic factors of severe course of the disease. MATERIAL AND METHODS: An observational study was conducted from March to July 2020 in the Pulmonology and Allergology Department of the University Hospital in Kraków, Poland. Consecutive patients with confirmed SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection were enrolled, and data about past medical history, signs and symptoms, laboratory results, imaging studies results, in-hospital management and outcomes was prospectively gathered. RESULTS: The study sample comprised 100 patients at the mean age of 59.2 (SD 16.1) years among whom 63 (63.0%) were male. Among them 10 (10.0%) died, 47 (47%) presented respiratory failure, 15 (15.0%) were transferred to the intensive care unit, 17 (17.0%) developed acute kidney injury, 7 (7.0%) had sepsis and 10 (10.0%) were diagnosed with pulmonary embolism. Multivariable analysis revealed age (OR 1.1; 95% CI 1.01-1.15), body mass index (BMI; OR 1.24; 95% CI 1.01-1.53), modified early warning score (MEWS; OR 3.95; 95% CI 1.48-12), the highest d-dimer value (OR 1.73; 95% CI 1.03-2.9) and lactate dehydrogenase (LDH; OR 1.16; 95% CI 1.03-1.3) to be associated with severe course of COVID-19. CONCLUSION: This observational study showed that almost half of hospitalized patients with COVID-19 developed respiratory failure in the course of the disease. Increasing age, BMI, MEWS, d-dimer value and LDH concentration were associated with the severity of COVID-19.

Temperature-Based Prediction of Joint Hardness in TIG Welding of Inconel 600, 625 and 718 Nickel Superalloys.

Welding is an important process in terms of manufacturing components for various types of machines and structures. One of the vital and still unsolved issues is determining the quality and properties welded joint in an online manner. In this paper, a technique for prediction of joint hardness based on the sequence of thermogram acquired during welding process is proposed. First, the correspondence between temperature, welding linear energy and hardness was revealed and confirmed using correlation analysis. Using a linear regression model, relations between temperature and hardness were described. According to obtained results in the joint area, prediction error was as low as 1.25%, while for HAZ it exceeded 15%. Future work on optimizing model and input data for HAZ hardness prediction are planned.

Perioperative cardiovascular complications rate and activity of coagulation and fibrinolysis among patients undergoing vascular surgery for peripheral artery disease and abdominal aortic aneurysm.

OBJECTIVES: To compare preoperative coagulation and fibrinolysis activity and incidence of perioperative complications between patients undergoing vascular procedures for peripheral artery disease and abdominal aortic aneurysm. METHODS: This is a substudy of a prospective observational cohort study (VISION; NCT00512109) in which we recruited patients aged ≥45 years, undergoing surgery for peripheral artery disease and abdominal aortic aneurysm. Blood samples were obtained 24 h preoperatively to measure platelet count, concentrations of coagulation coagulation (fibrinogen, factor VIII, von Willebrand factor:Ristocetin cofactor, antithrombin III), fibrinolysis (dimer D, plasmin-antiplasmin complexes, tissue plasminogen activator) markers and level of soluble CD40 ligand. Incidence of myocardial infarction, stroke, and death (composite endpoint) was assessed in 30-day follow-up. RESULTS: The study group included 131 patients at the mean age of 68.3 years among whom reason for surgery was peripheral artery disease in 77 patients (58.8%) and abdominal aortic aneurysm in 54 patients (41.2%). Peripheral artery disease group was characterized by higher platelet count (250.5 versus 209.5 (×103/µl), p = 0.001), concentrations of fibrinogen (5.4 versus 4.1 (g/l), p < 0.001), factor VIII (176.9 versus 141.9 (%), p < 0.001), von Willebrand factor:Ristocetin cofactor (188.9 versus 152.3 (%), p = 0.009), and soluble CD40 ligand (9016.0 versus 7936.6 (pg/ml), p = 0.005). The dimer D level was higher (808.0 versus 2590.5 (ng/ml), p < 0.001) in the abdominal aortic aneurysm group. Incidence of major cardiovascular events (death, myocardial infarction, stroke) within 30 days from surgery did not differ between the groups (39.0% versus 29.6%, p = 0.27). CONCLUSIONS: The study suggests higher activation of coagulation and relatively lower fibrinolytic activity in peripheral artery disease group compared to patients undergoing surgery for abdominal aortic aneurysm without a significant difference in cardiovascular outcomes.

Assessing MMA Welding Process Stability Using Machine Vision-Based Arc Features Tracking System.

Arc length is a crucial parameter of the manual metal arc (MMA) welding process, as it influences the arc voltage and the resulting welded joint. In the MMA method, the process' stability is mainly controlled by the skills of a welder. According to that, giving the feedback about the arc length as well as the welding speed to the welder is a valuable property at the stage of weld training and in the production of welded elements. The proposed solution is based on the application of relatively cheap Complementary Metal Oxide Semiconductor (CMOS) cameras to track the welding electrode tip and to estimate the geometrical properties of welding arc. All measured parameters are varying during welding. To validate the results of image processing, arc voltage was measured as a reference value describing in some part the process stability.