Time integration scheme for elastoplastic models based on anisotropic strain-rate potentials

Modelling of plastic anisotropy requires the definition of stress potentials (coinciding with the yield criteria in case of the associated flow rules) or, alternatively, plastic strain-rate potentials. The latter approach has several advantages whenever material parameters are determined by means of texture measurements and crystal plasticity simulations. This paper deals with a phenomenological description of anisotropy in elastoplastic rate-insensitive models, by using strain-rate potentials. A fully implicit time integration algorithm is developed in this framework and implemented in a static-implicit finite element code. Algorithmic details are discussed, including the derivation of the consistent (algorithmic) tangent modulus and the numerical treatment of the yield condition. Typical sheet-forming applications are simulated with the proposed implementation, using the recent non-quadratic strain-rate potential Srp2004-18p. Numerical simulations are carried out for materials that exhibit strong plastic anisotropy. The numerical results confirm that the presented algorithm exhibits the same generality, robustness, accuracy, and time-efficiency as state-of-the-art yield-criterion-based algorithms.International audienceModelling of plastic anisotropy requires the definition of stress potentials (coinciding with the yield criteria in case of the associated flow rules) or, alternatively, plastic strain-rate potentials. The latter approach has several advantages whenever material parameters are determined by means of texture measurements and crystal plasticity simulations. This paper deals with a phenomenological description of anisotropy in elastoplastic rate-insensitive models, by using strain-rate potentials. A fully implicit time integration algorithm is developed in this framework and implemented in a static-implicit finite element code. Algorithmic details are discussed, including the derivation of the consistent (algorithmic) tangent modulus and the numerical treatment of the yield condition. Typical sheet-forming applications are simulated with the proposed implementation, using the recent non-quadratic strain-rate potential Srp2004-18p. Numerical simulations are carried out for materials that exhibit strong plastic anisotropy. The numerical results confirm that the presented algorithm exhibits the same generality, robustness, accuracy, and time-efficiency as state-of-the-art yield-criterion-based algorithms

On the Development of a Digital Forensics Curriculum

Computer Crime and computer related incidents continue their prevalence and frequency, resulting in losses approaching billions of dollars. To fight against these crimes and frauds, it is urgent to develop digital forensics education programs to train a suitable workforce that can effectively investigate computer crimes and incidents. There is presently no standard to guide the design of digital forensics curriculum for an academic program. In this research, previous work on digital forensics curriculum design and existing education programs are thoroughly investigated. Both digital forensics educators and practitioners were surveyed and results were analyzed to determine the industry and law enforcement need for skills and knowledge for their digital forensic examiners. Based on the survey results and the topics that make up certificate programs in digital forensics, topics that are desired in digital forensics courses are identified. Finally, based on the research findings, six digital forensics courses and required topics are proposed to be offered in both undergraduate and graduate digital forensics programs

Antimicrobial resistance in clinical strains of Pseudomonas aeruginosa

Introduction. Pseudomonas aeruginosastands out as a predominant pathogen causing nosocomial infections, particularly in patients with underlying pathologies or compromised immune systems. The eradication of P. aeruginosahas become increasingly challenging, given its remarkable resistance to antibiotics. Strains of P. aeruginosadeploy both intrinsic and acquired resistance mechanisms, making them formidable against a wide array of antibiotics. Furthermore, adaptive antibiotic resistance in P. aeruginosa, a recently characterized mechanism, involves biofilm-mediated resistance and the formation of multidrug-tolerant persisted cells, contributing to infection relapse. Carbapenem-resistant P. aeruginosa has been identified by the World Health Organization as one of three bacterial species urgently requiring the development of new antibiotics. The overuse of antibiotics in treatment exacerbates the development of multidrug-resistant P. aeruginosastrains, rendering empirical antibiotic therapy ineffective against this microorganism. Aim. Determination of resistance profiles in Pseudomonas aeruginosastrains isolated from clinical bio substrates. Material and methods.The antimicrobial susceptibility profiles of P. aeruginosa isolates were determined using the standard disk diffusion method, following the guidelines outlined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST 2022). An isolate was classified as multidrug-resistant (MDR) if it demonstrated resistance to at least one antimicrobial agent in three or more distinct antibiotic classes. For quality control, the reference strain P. aeruginosa (ATCC 27853) was employed. Results. They analyzed 765 isolates from patients hospitalized in surgical wards. These strains were isolated from various pathological products, including the lower respiratory tract, pus, peritoneal fluid, urine, central venous catheter insertion, blood, feces, bile, and other secretions. P. aeruginosa strains exhibited the following levels of antibiotic resistance: 90.3% to ticarcillin, 78.5% to piperacillin, and 89.6%, respectively 66.8%, to penicillin’scombined with beta-lactamase inhibitors (ticarcillin with clavulanic acid and piperacillin with tazobactam). Resistance to antipseudomonal cephalosporins was observed at 67.6% for ceftazidime and 69.2% for cefepime, while resistance to carbapenems was 68.0% for imipenem and 58.2% for meropenem. Aminoglycoside resistance rates were 52.0% for gentamicin, 67.6% for tobramycin, and 46.4% for amikacin. Notably, 78.5% of strains exhibited cross-resistance to fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin), while resistance to colistin was only 8.4%. A significant majority, 697 strains of P. aeruginosa (91.0%), were classified as multidrug-resistant (MDR). Conclusions.The restricted susceptibility to antimicrobial agents and the frequent emergence of antibiotic resistance during therapy have significantly complicated the treatment of Pseudomonas aeruginosa infections. Consequently, continuous monitoring of drug resistance development in this organism group is of paramount importance. Additionally, the prudent and careful use of antimicrobial agents is imperative to counteract the progression of antimicrobial resistance

PARAMETER IDENTIFICATION OF ADVANCED PLASTIC POTENTIALS AND IMPACT ON PLASTIC ANISOTROPY PREDICTION

In the work presented in this paper, several strain rate potentials are examined in order to analyze their ability to model the initial stress and strain anisotropy of several orthotropic sheet materials. Classical quadratic and more advanced non-quadratic strain rate potentials are investigated in the case of FCC and BCC polycrystals. Different identifications procedures are proposed, which are taking into account the crystallographic texture and/or a set of mechanical test data in the determination of the material parameters.International audienceIn the work presented in this paper, several strain rate potentials are examined in order to analyze their ability to model the initial stress and strain anisotropy of several orthotropic sheet materials. Classical quadratic and more advanced non-quadratic strain rate potentials are investigated in the case of FCC and BCC polycrystals. Different identifications procedures are proposed, which are taking into account the crystallographic texture and/or a set of mechanical test data in the determination of the material parameters

Time integration scheme for elastoplastic models based on anisotropic strain-rate potentials

Modelling of plastic anisotropy requires the definition of stress potentials (coinciding with the yield criteria in case of the associated flow rules) or, alternatively, plastic strain-rate potentials. The latter approach has several advantages whenever material parameters are determined by means of texture measurements and crystal plasticity simulations. This paper deals with a phenomenological description of anisotropy in elastoplastic rate-insensitive models, by using strain-rate potentials. A fully implicit time integration algorithm is developed in this framework and implemented in a static-implicit finite element code. Algorithmic details are discussed, including the derivation of the consistent (algorithmic) tangent modulus and the numerical treatment of the yield condition. Typical sheet-forming applications are simulated with the proposed implementation, using the recent non-quadratic strain-rate potential Srp2004-18p. Numerical simulations are carried out for materials that exhibit strong plastic anisotropy. The numerical results confirm that the presented algorithm exhibits the same generality, robustness, accuracy, and time-efficiency as state-of-the-art yield-criterion-based algorithms.Financement Région Lorrain

PRACTICAL APPLICATION WITH PLC IN MANIPULATION OF A ROBOTIC ARM

This paper presents the use of a robotic arm PLC Siemens in order not using CNC commands. This is done by programming the PLC ladder diagram language that makes movement on the three axes of the arm by means of stepper motors. Required command console PLC is built with the help of a touch screen HMI Weintek. In the user interface are introduced distances and displacement speeds on the three axes

Diabetes mellitus: interdisciplinary medical, surgical and psychological therapeutic approach

Diabetes mellitus is a complex and widespread metabolic disease, having extremely complex implications (biological, psychological, social) for patients. Understanding the pathophysiology of diabetes (majorly influenced by various factors such as genetic predisposition, age, lifestyle choices, etc.) is essential for the prevention of this condition and the establishment of effective treatment strategies. The latest and relevant literature data related to the epidemiology, pathophysiology, and treatment of diabetes are presented, after an exhaustive review of the articles published on this topic and indexed in the WOS, PubMed, Scopus and Google Scholar databases. Preventing or delaying the onset of diabetes can be achieved in some patients with type 2 diabetes. After onset, treatment of diabetes is complex, involving a comprehensive approach (pharmacological interventions, lifestyle changes, surgical interventions in selected cases, as well as psychological support), depending on the stage of the disease and possible associated complications. Finally, diabetes is often asymptomatic in the initial stages, so an early diagnosis remains the essential element for the best subsequent therapeutic control

Gastric cancer; actualities and perspectives of early diagnosis and targeted therapy

Gastric cancer is an extremely aggressive form of malignancy that, if left untreated, is life-threatening. Improved survival rates depend on early detection of the disease, as well as on the combination of different forms of treatment (surgery, chemotherapy, radiotherapy, immunotherapy, etc.). Screening methods have brought real benefit in early detection of malignancies, but many cases are still diagnosed at advanced stages. The current study is a review related to actualities and perspectives of early diagnosis and targeted therapy of gastric cancer. After an extensive review of the literature, epidemiological, diagnostic and treatment data are presented. The open surgical approach is used in emergency centers or with a low surgical activity, while the minimally invasive approach (laparoscopic, robotic) is possible in large centers dedicated to the treatment of gastric cancer. In the near future, new diagnostic and therapeutic tools are expected to appear, not only to cure cancer definitively, but also to be able to prevent it, if possible, without radically changing the lifestyle of the population

Parameter identification of advanced plastic potentials and impact on plastic anisotropy prediction

In the work presented in this paper, several strain rate potentials are examined in order to analyze their ability to model the initial stress and strain anisotropy of several orthotropic sheet materials. Classical quadratic and more advanced non-quadratic strain rate potentials are investigated in the case of FCC and BCC polycrystals. Different identifications procedures are proposed, which are taking into account the crystallographic texture and/or a set of mechanical test data in the determination of the material parameters

SECURITY AND INTELLIGENCE. STRATEGIC ASPECTS AND ORGANIZATIONAL MODEL

The present study approaches the notion of security that is considered the main condition for the existence and development of a nation (state entity) in a state of peace, seen in direct relationship with the state-nation imbalance - a defining coordinate of the of law modernity, the main cause of disputes and the element of continuity of peace, crisis and war. In the current context, prospective security should be the landmark low of acknowledging the needs and underlying policies and strategies, which in relation to the dynamics of the present situation contributes to the orientation and appropriateness of the strategic decisions in order to avoid undesirable developments of the nation (stale)