Plastic flow behavior of twinning induced plasticity steel from low to warm temperatures

This work investigates the tensile behavior of twinning induced plasticity (TWIP) steel under room to warm temperatures. Stress-strain flow curves have been obtained from steady-state uniaxial tensile tests performed at different temperatures, that is, from 20 to 800 °C, and different engineering strain rates, 0.003 and 0.5 s−1. The yield and ultimate tensile strength, elongation at fracture, reduction of area, strain hardening exponent and strain hardening rate have been defined to describe the plastic behavior of TWIP steel. It has been found that the plastic flow behavior of TWIP steel is characterized by negative strain rate sensitivity and strain hardening, at temperatures from 20 to 300 °C, until the twinning mechanism occurs. At these temperatures, dynamic strain aging starts at the beginning of plastic deformation, with the appearance of fluctuations in the work hardening rate and local strain rate. Pronounced local serrations also appear at 300 °C and 0.003 s−1. Plastic deformation is mainly driven by dislocation gliding at 550 and 800 °C, and mechanical twins are absent. As a result, negative strain rate sensitivity and local serrations disappear in the stress-strain curves. Creep also contributes notably to plastic deformation at 800 °C, as was also observed on the fracture surfaces of tensile samples. Mechanical twins were only visible for the lower temperatures. The grains in the sample tested at 800 °C and 0.003 s-1 were fully recrystallized. Keywords: Twinning induced plasticity steel, Plastic flow behavior, Warm temperature, Mechanical strength, Strain hardening, Dynamic strain agin

On plastic notch effects in quenched and tempered steels

Presentazione orale al convegno TMS 2010 - 139th Annual Meeting & Exhibition, svoltosi a Seattle (USA) dal 14/02/2010 al 18/02/201

La filiera automotive in Emilia-Romagna

In questo capitolo utilizziamo la metodologia sviluppata da Pavone e Russo (2017) per classificare le specializzazioni produttive della filiera automotive. Tale metodologia utilizza un\u2019analisi automatica delle descrizioni testuali delle attivit\ue0 delle imprese contenute nel database della popolazione statistica utilizzata nell\u2019Osservatorio automotive 2017. Il capitolo presenta un quadro dell\u2019industria metalmeccanica dell\u2019Emilia-Romagna e delle specializzazioni nella filiera automotive della regione. Sono commentati i risultati relativi all\u2019indagine dell\u2019Osservatorio ed un approfondimento realizzato grazie alle interviste condotte dagli studenti dell\u2019Universit\ue0 di Modena e Reggio Emilia. Le conclusioni del capitolo propongono uno sviluppo dell'indagine empirica sui temi della digitalizzazione

RIS3 in macro-regional strategies: tools to design and monitor integrated territorial development paths

This paper highlights the importance of combining quantitative and qualitative analyses . It combines multidimensional analysis of the characteristics of EU macro-regions with a comparative, qualitative perspective on priorities outlined in regional innovation strategies. It shows that bottom-up strategies for regions can support integrated approaches, and that the RIS3 database in particular can help with the successful design and implementation of policie

Use of electrode displacement signals for electrode degradation assessment in resistance spot welding

In resistance spot welding, the quality of welds is not only affected by the correct design of the welding cycle, but also by the electrode degradation that occurs over time. This work proposes a novel approach to indirectly monitor the electrode degradation during welding by analyzing the electrode displacement signal from a non-contact sensor embedded in the welding machine and the electrode tip shape obtained from carbon imprint tests. As a result of an experimental campaign involving more than 1200 weld spots, the electrode speed during the final hold stage has been determined as the most explanatory feature describing the electrode displacement. Based on the mechanical strength of spot welds, the electrode contact face area has been defined as the most representative feature characterizing electrode degradation. A regression analysis has been carried out to infer a relationship between the electrode speed and the contact area representative of tool wear. A Neural Network has been built to use some features extracted from the electrode displacement signals to predict the contact area and thus indirectly the electrode degradation. The model has shown a good accuracy, with a mean error of the contact area about 1.61 mm2, and with a standard deviation of about 3.73 mm2. The data-driven approach proposed allows through the evaluation of the electrode contact area to have better real-time knowledge and control of the welding process

Genetic variants of Y chromosome are associated with a protective lipid profile in black men

Objective— Gender and ethnicity modulate the phenotypic expression of cardiovascular risk factors. In particular, men are at higher risk of developing cardiovascular diseases compared to women, whereas black populations of African origin display reduced mortality from coronary heart disease (CHD) as compared to both whites and South Asians. Because the male-specific region (MSY) of the human Y chromosome is an obvious candidate for gender-related differences in the development of cardiovascular diseases, we aimed to identify genetic variants of MSY influencing cardiovascular risk profile in different ethnic groups. Methods and Results— We genotyped 4 polymorphisms of MSY (HindIII±, rs768983 of TBL1Y, rs3212292 of USP9Y, and rs9341273 of UTY genes) in 579 men of different ethnic groups (blacks, South Asians, and whites) from UK and in 301 whites in Italy. We found that the TBL1YA USP9YA haplotype, present only in blacks in whom it represents the most frequent allelic combinations (AA: n=125; all other combinations: n=45), was associated with lower levels of triglycerides (P=0.025) and higher levels of HDL-cholesterol (P=0.005) as compared to the other haplotypes. Conclusion— The TBL1YA USP9YA haplotype of the Y chromosome, present only in black people of African origin, attributes a favorable lipoprotein pattern, likely to contribute to their reduced susceptibility to coronary heart disease. The study evaluated the association of genetic variants of the male-specific region of the Y chromosome with cardiovascular risk factors in different ethnic groups. The most frequently observed haplotype in black people was associated with a favorable lipoprotein pattern, thus contributing to the lower rate of cardiovascular diseases in blacks

Successful smoking cessation with electronic cigarettes in smokers with a documented history of recurring relapses: a case series

<p>Abstract</p> <p>Introduction</p> <p>Smoking cessation programs are useful in helping smokers to quit, but smoking is a very difficult addiction to break and the need for novel and effective approaches to smoking cessation interventions is unquestionable. The E-cigarette is a battery-powered electronic nicotine delivery device that may help smokers to remain abstinent during their quit attempt. We report for the first time objective measures of smoking cessation in smokers who experimented with the E-cigarette.</p> <p>Case presentation</p> <p>Three Caucasian smokers (two men aged 47 and 65 years and one woman aged 38 years) with a documented history of recurring relapses were able to quit and to remain abstinent for at least six months after taking up an E-cigarette.</p> <p>Conclusions</p> <p>This is the first time that objective measures of smoking cessation are reported for smokers who quit successfully after using an E-cigarette. This was accomplished in smokers who repeatedly failed in previous attempts with professional smoking cessation assistance using the usual nicotine dependence treatments and smoking cessation counselling.</p

Learning online: Remote teaching and university student’s engagement

The COVID-19 pandemic has had a dramatic impact on many dimensions of living and working conditions, and uncertainties about the developments that we shall still face in the near future. This paper analyses the implications of a forced overnight push to online teaching. Drawing upon an online survey conducted during the 2020 lockdown by the University of Modena and Reggio Emilia, this article describes students' living and studying conditions revealed by a large set of open and closed questions. The survey provides significant information on the students' real off-campus conditions, crucial data for the multidimensional analysis by combining non-parametric multivariate analysis of closed questions with textual analyses. It offers important indications about the most useful tools for inclusive teaching across thematic areas and highlights the main difficulties that emerged during the lockdown. Reflections on advantages and disadvantages, strengths and weaknesses in the innovative learning environment set up overnight are offered at a policy level

Learning online: Remote teaching and university students’ engagement

The COVID-19 pandemic has had a dramatic impact on many dimensions of living and working conditions, and uncertainties about the developments that we shall still face in the near future. This paper analyses the implications of a forced overnight push to online teaching. Drawing upon an online survey conducted during the 2020 lockdown by the University of Modena and Reggio Emilia, this article describes students’ living and studying conditions revealed by a large set of open and closed questions. The survey provides significant information on the students’ real off-campus conditions, crucial data for the multidimensional analysis by combining non-parametric multivariate analysis of closed questions with textual analyses. It offers important indications about the most useful tools for inclusive teaching across thematic areas and highlights the main difficulties that emerged during the lockdown. Reflections on advantages and disadvantages, strengths and weaknesses in the innovative learning environment set up overnight are offered at a policy level

Weldability and monitoring of resistance spot welding of Q&P and TRIP steels

This work aims at investigating the spot weldability of a new advanced Quenching and Partitioning (Q&amp;P) steel and a Transformation Induced Plasticity (TRIP) steel for automotive applications by evaluating the effects of the main welding parameters on the mechanical performance of their dissimilar spot welds. The welding current, the electrode tip voltage and the electrical resistance of sheet stack were monitored in order to detect any metal expulsion and to evaluate its severity, as well as to clarify its effect on spot strength. The joint strength was assessed by means of shear and cross tension tests. The corresponding fracture modes were determined through optical microscopy. The welding current is the main process parameter that affects the weld strength, followed by the clamping force and welding time. Metal expulsion can occur through a single large expulsion or multiple expulsions, whose effects on the shear and cross tension strength have been assessed. Longer welding times can limit the negative effect of an expulsion if it occurs in the first part of the joining process. The spot welds exhibit different fracture modes according to their strengths. Overall, a proper weldability window for the selected process parameters has been determined to obtain sound joints