Wear investigation of selective α-Fe2O3 oxide layers generated on surfaces for dry sheet metal forming

To realize a dry sheet metal forming process, α-Fe 2 O 3 oxide layers were investigated regarding their friction characteristics, wear behavior and surface energy depending on different surface qualities of the specimens examined. The oxide layers were generated in a new hybrid batch furnace. The layer generation on all specimens of the tool steel 1.2379 used was performed at a target temperature below the annealing temperature (≈ 510 °C). Friction coefficients were examined with plane strip drawing tests. Wear experiments with oxidized wear specimens with variable surface topographies were carried out up to several thousand strokes per surface condition

Inductive heat treatment as an alternative tempering method for the selective oxidation of 1.2379 tool steel surfaces

Selective surface oxidation of a hardened conventional tool steel (1.2379) was carried out with controlled oxygen partial pressures at elevated temperatures. In order to obtain a defined oxygen partial pressure, the experiments were carried out under pure nitrogen and silane doped nitrogen atmosphere. Depending on the actual heat treatment parameters, morphologically different iron based oxide systems could be generated. Some of the selectively oxidized surfaces featured advantageous tribological properties, which appear suitable for lubricant free forming applications. For selected oxide layer systems a batch process for the heat treatment was developed. This set-up is described including the sensitive process control with respect to gas composition. The oxide layer systems generated were characterized by analyzing their composition and surface morphology. In addition, an inductive heat treatment procedure was developed. With this hybrid approach mixed layer systems could be realized that combine different characteristics of conventionally oxidized specimen surfaces.

Selective thermally oxidised tool surfaces for dry deep drawing

Within the scope of German Research Foundation (DFG) Priority Programme (SPP) 1676, this subproject deals with the research of a technology to substitute lubricants in the deep drawing process by selective thermally oxidised tool surfaces. In this context, different atmospheres and methods for selective oxidation of the tool surfaces were investigated. The oxide systems generated were characterised and analysed using highresolution analysis for examining and classifying their tribological properties [1]. With regard to the layer adhesion and the resulting measurements of coefficients of friction (COF), an α-Fe2O3 layer system was chosen, which proved promising for application in deep drawing processes. A special specimen geometry was developed that allows investigation of the tribological wear behaviour of the layer in the deep drawing process. This geometry was intended to mimic the conditions in a deep-drawing process with high cycle numbers of up to 5000 on a laboratory scale and to be suitable for the subsequent analysis methods [2, 3]. The wear specimens were examined on a developed wear test bench and, according to loading cases at dry deep drawing, tested with the sheet metal DP600 + Z under 90° deflection. [4, 5] Based on the results from the wear tests, a numerical FE model was developed capable of simulating the material wear as a function of the process parameters. This served as a numerical tool for predicting layer failure as well as for analysing wear critical areas on the deep drawing tools. In the further course, the heat treatment equipment was upgraded so that samples could be heated inductively in a batch process. This led to increased surface activation and more economical oxidation processes [6]. Since near-surface chromium carbides strongly influence and even prevent selective oxidation, a powder-metallurgically manufactured steel (PM) was also examined. Those surfaces featured chromium carbides in small quantities and to a lesser extent. The selective oxidation of these PM steel surfaces showed excellent results in terms of oxidisability compared to conventionally manufactured steel, as well as constant lower COFs [7]. Following the tribological wear investigations, FE analyses were used to create a modular tool concept enabling the installation of oxidised inserts in defined sections of the tool. After manufacturing, this modular tool was used to validate the applicability of the developed layer system as well as the numerical wear model [8]. In addition to the deep drawing steel DP600 + Z, the electrolytically galvanised deep drawing steel DC04 + ZE was used in these experiments [9]. Tests with both deep-drawing steels demonstrate the good deep-drawability in the dry state with oxidised mould inserts.00102

Protocol for a Scoping Review: Establishing Ground Truth for Delirium Prediction Models in Adult Patients in Acute Care

Background: Artificial Intelligence (AI) in healthcare has shown potential, particularly utilising Electronic Health Record (EHR) data to predict diseases. Delirium, characterised by cognitive changes and attention disruption due to underlying medical conditions, presents a significant obstacle to healthcare. It has been linked to increased morbidity, mortality, dementia progression, elevated costs, and premature transfers to long-term care facilities. The lack of a robust ground truth is a significant challenge faced by AI systems developed to predict delirium. The ground truth consists of verified labels for the outcome to be predicted. With delirium being underreported and poorly documented in hospital settings, creating an accurate and reliable ground truth for delirium prediction systems needs a well-thought-out strategy. Aim: The aim of this scoping review is to summarise and discuss strategies to establish ground truth in datasets used to develop delirium prediction systems for adults in acute care settings. Methods: We will use the Population, Concept, and Context (PCC) approach to define search blocks, and PubReMiner, along with a librarian, to identify relevant search terms. The search will be conducted in three databases (PubMed, IEEE, Cochrane Library). We will use Covidence for the screening process and extract data via REDCap using an extraction table guided by the PROBAST tool and the CHARMS checklist, including a risk of bias assessment. Results: The forthcoming journal article will summarise reported strategies used to establish ground truth for the development of delirium prediction models and discuss their strengths and weaknesses. Conclusion: Developers could benefit from selecting a suitable strategy to establish ground truth based on the summary and discussion presented in this scoping review. This may ultimately improve the accuracy of predictive models by enabling access to higher quality training data and allowing more reliable evaluation of predictive performance, thus increasing model efficiency for real-world implementation

The Spectrum of Co-Diagnoses in Patients with Colorectal Cancer: A Retrospective Cohort Study of 17,824 Outpatients in Germany

Background: The prognosis of colorectal cancer (CRC) patients is determined to a decisive extent by comorbidities. On the other hand, anti-cancer treatments for CRC are associated with relevant toxicities and may therefore cause additional comorbidities. Methods: This retrospective cohort study assessed the prevalence of various diseases in patients 12 months before and 12 months after an initial diagnosis of colorectal cancer (ICD-10: C18, C20) in 1274 general practices in Germany between January 2000 and December 2018. The study is based on the Disease Analyzer database (IQVIA), which contains drug prescriptions, diagnoses, and basic medical and demographic data. Patients with and without CRC were matched by sex, age, and index year. Results: We identified several diagnoses with a significantly higher prevalence among CRC patients 12 months prior to the index date compared to controls. These diagnoses included gastrointestinal hemorrhage, hemorrhoids, perianal venous thrombosis, and abdominal and pelvic pain, as well as functional intestinal disorders. In contrast, the prevalence of lipid metabolism disorder, depression, hypertension, coronary heart disease, or acute bronchitis was significantly lower in CRC cases. After diagnosis of CRC, we found a significantly higher prevalence of anemia, polyneuropathies, functional intestinal disorders, and chronic kidney disease among CRC patients compared to the control group, while the prevalence of acute upper respiratory infections of multiple and unspecified sites and acute bronchitis was significantly lower in CRC patients compared to non-CRC patients. Conclusions: In the present study, we identified a variety of diseases occurring at higher or lower frequencies in CRC patients compared to matched controls without CRC. This might help to select patients for early CRC screening and improve the clinical management of CRC patients

GLP-2 analog teduglutide significantly reduces need for parenteral nutrition and stool frequency in a real-life setting

Background: To evaluate the benefits of teduglutide in a real-life setting, we analyzed the data of 14 patients with short bowel syndrome treated with teduglutide. Additionally, we studied glucagon-like peptide 2 (GLP-2) receptor expression in samples of small intestinal and colonic tissue to provide explanations for clinical observations. Methods: Stool frequency and consistency, sensation of thirst, parental calorie or fluid uptake and the number of days on parenteral support per week were collected for up to 2 years. Quantitative real-time polymerase chain reaction of the GLP-2 receptor in healthy controls was performed to better understand clinical response in different patient subgroups. Results: There was a significant reduction in parenteral support after 24 and 48 weeks (by 11.0 and 36.6%, respectively; p < 0.05). Further major improvements were made in several patients after over 1 year (reduction by 79.3%, p < 0.05). The proportion of patients who reduced parenteral support by at least 20% was 33.3%, 54.5% and 71.3% after 24 weeks, 48 weeks and beyond 1 year, respectively. Patients on daily parenteral support showed late but strong amelioration. The reduction of thirst was the earliest marker for response. While stool consistency increased ( p < 0.01), stool frequency decreased ( p < 0.05) significantly after 12 weeks. This reduction was even more pronounced in patients with colon in continuity. Supporting these clinical observations, we found a stronger physiological expression of the GLP-2 receptor in the colon than in the small intestine. Conclusions: Patients benefit from teduglutide in a real-life setting, but in contrast to randomized, controlled studies reduction of parenteral support took longer. We identified early clinical markers of response, such as stool consistency and frequency as well as sensation of thirst. Clinical and molecular observations support the role of the colon as an important target organ of teduglutide

Characterization and Modeling of Nano Wear for Molybdenum-Based Lubrication Layer Systems

As a result of global economic and environmental change, the demand for innovative, environmentally-friendly technologies is increasing. Employing solid lubricants in rolling contacts can reduce the use of environmentally harmful greases and oils. The aim of the current research was the development of a solid lubricant system with regenerative properties. The layer system consisted of a molybdenum (Mo) reservoir and a top layer of molybdenum trioxide (MoO3). After surface wear, Mo is supposed to react with atmospheric oxygen and form a new oxide. The determination of the wear volume of thin layers cannot be measured microscopically, which is why the wear behavior is initially determined on the nano level. In this work, single Mo and MoO3 coatings prepared by physical vapor deposition (PVD) are characterized by nano testing. The main objective was to determine the wear volume of the single coatings using a newly developed method considering the initial topology. For this purpose, nano-wear tests with different wear paths and normal forces were carried out and measured by in situ scanning probe microscopy (SPM). Based on the characteristic values determined, the coefficient of wear was determined for wear modeling according to Sarkar. The validation of the wear model developed was carried out by further wear tests on the respective mono layers

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Reconstructed instantaneous 3D chemiluminescence field of Flame I, rotated about an axis 45° to the burner exit plane to illustrate the flame geometry detail

The Structure of DSR Knowledge as Reflected by DESRIST - A Citation Analysis (2009-2015)

International audienceThe design science research (DSR) paradigm is now established and reco gnized within the information systems (IS) community. The members of the DSR community have a common language and shared perceptions. However, it remains to define what constitutes the fundamental issues, theories, applications, and the main findings in this area. In other words, how may the knowledge of the field be characterized? The aim of this paper is to determine and analyze the DSR body of knowledge, based on publications in the DESRIST conference. To this end, we perform a citation and co-citation analysis of the papers published in this conference between 2009 and 2015. The co-citation analysis leads to the identification of several clusters representing what we believe to be a good overview of the structure of the DSR body of knowledge. We contend that our findings will help researchers to identify DSR areas likely to lead to future research