91 research outputs found
Atti del 17° Convegno Nazionale Gruppo Italiano Frattura
No full textThis book presents researches on the fracture mechanics as: A short crack model for fatigue limit of press-fittings in railway axles; A weakest – link analysis for fatigue strength of Components containing defects; Local compliance experiments and crack closure models; Application of new methods to evaluate crack closure in the near-threshold fatigue crack growth regime; Thermo-mechanical analysis of elastic cracks In heterogeneous materials by FEM and VCFEM; Crack propagation in poroelastic fluid-saturated solids at intersonic velocities; Microstructural investigation and thermal shock behaviour of mullite-cordierite refractory materials; Indentation and imprint mapping for inverse analysis of quasi brittle fracture; High reliability ceramic laminates by design; Reliability assessment of a SiC based component for high temperature application; Time-scale effects on acoustic emission due to elastic waves propagation in monitored cracking structures; Hysteretic flexural behaviour of a reinforced concrete beam with a T crosssection; Nanoscale strain localization: the instability of strainions; Structural monitoring and life-time assessment of medieval towers; Size effect in grained materials: extreme value theory approach; Theoretical and numerical investigation on internal instability phenomena in composite materials; Numerical approach and experimental validation of composite soundproofing panels for aeronautical applications; Surveillance system airborne composite radome design; Elastic interaction of delamination in composites; Strain rate dependence of the anisotropic fracture Toughness of rubber
modified polypropylene films; Mixed-mode crack growth in toughened PMMA; Applicability of the load separation criterion and the normalization method to high-rate testing of ductile polymers; A nonlinear FE method for the prediction of slabs on grade behaviour; Quantized fracture mechanics and related applications for predicting the strength of defective nanotubes
comparative theoretical-experimental evaluation of conrod little-eye stress analysis; A modified relaxation-model for the prediction of residual stresses in twodimensional rolling/sliding contact; The Nondimensional Plasticity Rotational Parameter used in DWT Tests:
Evaluation by means of Finite Element; Cracking mechanisms in a Hot-dip zinc coated steel; Cracking mechanisms in a Hot-dip zinc coated steel ferritic and austenitic sintered stainless steels Fatigue crack propagation resistance: hydrogen embrittlement influence; Fracture toughness KIvM measurement of non-brittle metallic materials by “Chevron Notched” specimens; Fatigue crack growth behavior of nitrided and shot peened specimens; Fracture toughness of plastic-mold steels: dependence upon heat treatment and
microstructure; Scale-independent constitutive law for concrete in compression; Influence of the intermediate material on the singular stress field in tri-material junctions; On nonlocality and locality: differential and discrete formulations; Fracture response of cracked orthotropic plates; Effect of interaction between collinear cracks on the strength distribution of brittle materials; Stress intensity factors for a subsurface crack in a two dimensional half-space; An implicit gradient stress failure condition
Phantom scalar-tensor models and cosmological tensions
No full textWe study three different extended scalar-tensor theories of gravity by also
allowing a negative sign for the kinetic term for the scalar field in the
Jordan frame. Our scope is to understand how the observational constraints for
these models cope with the volume of the parameter space in which the theory is
healthy. Models with a negative kinetic term lead to decreasing effective
gravitational constant with redshift and behave as an effective relativistic
component with a negative energy density as opposite to their corresponding
version with a standard kinetic term. As a consequence, we find that the
extended branch with a negative sign for the kinetic term correspond in general
to lower and compared to CDM. We find that in all the
cases with a negative sign for the kinetic term studied here, cosmological
observations constrain these models around GR and prefer a volume of the
parameter space in which the theory is not healthy since the scalar field
behave as a ghost also in the related Einstein frame. We show that also in the
phantom branch early modify gravity with a quartic coupling can substantially
reduce the tension fitting the combination of cosmic microwave background
data from Planck, baryon acoustic oscillations from BOSS and eBOSS, and
Supernovae from the Pantheon sample with calibration information by SH0ES.Comment: 33 pages, 11 figures, 6 table
Cosmological effects of the Galileon term in Scalar-Tensor Theories
No full textWe study the cosmological effects of a Galileon term in scalar-tensor
theories of gravity. The subset of scalar-tensor theories considered are
characterized by a non-minimal coupling , a kinetic term with
arbitrary sign with , a potential
, and a Galileon term . In addition to the modified dynamics, the Galileon term provides a
screening mechanism to potentially reconcile the models with General Relativity
predictions inside a Vainshtein radius. Thanks to the Galileon term, the
stability conditions, namely ghost and Laplacian instabilities, in the branch
with a negative kinetic term () are fulfilled for a large volume of the
parameter space. Solving numerically the background evolution and linear
perturbations, we derive the constraints on the cosmological parameters in
presence of a Galileon term for different combination of the cosmic microwave
background (CMB) data from Planck, baryon acoustic oscillations (BAO)
measurements from BOSS, and supernovae from the Pantheon compilation. We find
that the Galileon term alters the dynamics of all the studied cases. For a
standard kinetic term (), we find that Planck data and a compilation of
BAO data constrain the Galileon term to small values that allow screening very
inefficiently. For a negative kinetic term (), a Galileon term and a
non-zero potential lead to an efficient screening in a physically viable regime
of the theory, with a value for the Hubble constant today which alleviates the
tension between its CMB and local determinations. For a vanishing potential,
the case with and the Galileon term driving the late acceleration of the
Universe is ruled out by Planck data.Comment: 23 pages, 15 figures, 4 table
M. Pasculli Ferrara, Atlante tematico del Barocco in Italia. L’arte dei marmorari in Italia meridionale. Tipologie e tecniche in età barocca
No full textThe art of marble in southern Italy is a unique volume because it proposes the analysis of the Neapolitan workshops in the production of marble artistic artefacts. This fashion spread from Naples throughout southern Italy and boasts important sculptors such as Angelo Landi, Cosimo Fanzago, Finelli and SanmartinoL'arte dei marmorari in Italia meridionale costituisce un volume unico nel genere perchè propone l'analisi delle botteghe napoletane nella produzione di manufatti artistici in marmo. Tale moda si diffuse da Napoli in tutta l'Italia meridionale e vanta importanti scultori come Angelo Landi, Cosimo Fanzago, Finelli e Sanmartin
Role of blue dye for sentinel lymph node detection in early endometrial cancer
No full textBackground: Sentinel Lymphonode analysis has become a barely new and innovative way to treat early stages of endometrial cancer (Ballester et al., Lancet Oncol 469â476, 2011; Buda et al., Ann Surg Oncol 2975-81, 2016). Indocyanine green cervical injection is considered gold standard for mapping nodesâ drainage. Blue dye is used as a valid alternative in many centers, due to the lower cost of execution. The objective of this video is to prove that methylene blue dyeâs cervical injection is a valid and âlow-costâ method to obtain mapping of lymphatic drainage in patient with early endometrial cancer. Methods: Fifty-four-year old women, with a recent diagnosis of endometrial cancer IA G2, we performed a radical Hysterectomy type A. We diluted in equal proportions the blue dye and saline and injected 1Â cl in depth and 1Â cl on the surface of the cervix, at 3 oâclock and 9 oâclock. After 20Â min, it was shown with precision the lymphatic drainage until the first lymph node station from both sides. Results: One external iliac lymph node and one obturator were resected on the left side and one external iliac on the right side. On histological analysis, none of the lymph nodes had any location of metastasis, neither micro-metastasis. Myometrial infiltration was 8/19Â mm. Conclusions: Blue dye cervical injection is a âlow-costâ, safe, and satisfactory procedure to point out Sentinel Lymph Node of uterus drainage. Other tracers, such as indocyanine green, are widely used in gynecological oncology, but with a higher cost of the product and the needing of a dedicated optical filter to be shown on human view
Laparoscopic Approach for Shull Repair of Pelvic Floor Defects
No full textStudy Objective: To prove the feasibility of the Shull technique by a laparoscopic approach in a patient affected by pelvic organ prolapse (POP) with apical loss of support. Design: A step-by-step video demonstration (Canadian Task Force classification III). Setting: University hospital. Ethics Committee ruled that approval was not required for this study. Patient: A 53-year-old woman with a POP-Q stage IV, left ovarian cyst. Intervention: Laparoscopic uterosacral ligament suspension. Measurements and Main Results: According to the National Health and Nutrition Examination Survey, approximately 3% of women in the United States report symptoms linked to POP, with approximately 300 000 POP surgeries each year in the United States. More recent studies show a lower reoperation rate of approximately 6% to 30%, and this lower reoperation rate may reflect improvement in surgical technique and POP surgery that includes suspension of the vaginal apex, which is associated with a decreased reoperation rate, commonly done by vaginal vault suspension to uterosacral ligaments. Suturing the apex to the high (proximal) portion of each uterosacral ligament is more commonly performed vaginally, although abdominal and laparoscopic approaches are suitable. It represents a modification of the uterosacral ligament suspension procedure described by Shull. A 53-year-old woman with a POP-Q stage IV, left ovarian cyst and an "elongatio colli" underwent a total hysterectomy and bilateral ovariectomy with vaginal dome uterosacral ligament suspension performed laparoscopically. The total operating time was 80 minutes, with a blood loss volume of less than 50 mL. The patient was hospitalized for 2 days. There were no postoperative complications in 30 days. Conclusion: The Shull laparoscopic surgery for advance POP with reconstruction of the anterior compartment is technically feasible
Fracture Response of cracked orthotropic plates
No full textThe solution of the elastostatic problem of an orthotropic body having a central inclined crack and subjected at infinity to a uniform biaxial load has been employed. It is assumed that the crack line does not coincide with an axis of elastic symmetry of the body. The stress filed is reported.
The topic of the present paper is the extension of the maximum Circumferential Tensile Stress Criterion to orthotropic materials, in order to obtain the crack initiation angle, pointing out the effects of orthotropy and load biaxiality. The influence of the non singular terms on the crack initiation angle is also investigated
Reconstruction of the physics of Inflation from next generation cosmological experiments
No full textIn this work, we study the problem of the reconstruction of the
physics of inflation using current and future cosmological data from cosmic microwave background and gravitational waves experiments. In particular, we focus on the so-called (supergravity) α-attractor models of inflation constraining the shape of the potential
as well as the reheating properties of the these models. Furthermore, we approach the
problem of the reconstruction of the variation of the inflaton field during inflation providing a next order expression in terms of the inflationary variables
Proceeding of the 17th National Conference of Italian Group of Fracture
No full textBologna, seat of the first and prestigious university in the western world due to the presence of numerous renowned personalities such as Luigi Galvani, Augusto Righi and Francesco Petrarca, holds for the first time the national congress of the Italian Group of Fracture.
The topics of the meeting concern the most recent scientific breakthroughs in the study of fracture and its implications: the historical development, the harmonisation of the laws and of the standards for the determination of fundamental parameters, the experiences deriving from the collaborations with industries and, finally, the didactic and educational experiences related to the concept of fracture.
As usual, the congress carries on the debate and confrontation about a historically founded problem, on which institutions, facilities, conventions, standards have been developing, but which still poses questions, research and innovation instances.
The proceedings of this 17th National Congress of the Italian Group of Fracture assume a meaning that overcomes the simple aspect of the collection of memories, dedicated to the cultural moment the congress itself represents. They will have indeed a worldwide diffusion, through the distribution to all the participants to the 11th International Conference on Fracture, which will take place in Turin, on 20th – 25th March 2005, co-organized by this Association. counting
These proceedings certainly do not want to represent all the work the Italian scientific community is achieving on the topic of fracture, but only an impression. It puts in evidence the work, of undoubted quality, that is being carried on by the Members of this association, which represents in Italy the similar European association ESIS and the international ICF.
The congress, organized in collaboration by the University of Bologna and the Materials and New Technologies Unit of ENEA at Faenza Research Centre, took place in the 'Villa Gandolfi Pallavicini'. The villa, surrounded by a park and lying east to Bologna, was built in 17th century by a noble family from Bologna and among its famous guests, it can include the 14-year-old Wolfgang Amadeus Mozart. Nowadays it is the location of the Institute of Advanced Studies of the local university, an institution that contributed to the perfect success of the event.
Our hope is that the edition at Bologna may represent a spur so that the Italian Group of Fracture will carry on its important and profitable accomplishments, as it has been so far.
We are sincerely grateful to the authors of the works collected in this volume, which are the premise for our wish to come true.
Last but not least, special thanks to professor Alessandro Freddi, Director of the Institute of Advanced Studies of the University of Bologna, and to professors G. C. Sih and E. E. Gdoutos, authors of the invited lectures.
Angelo Finelli Lucio Nobile
ENEA - C.R. Faenza University of Bologn
Analysis of the influence of the anisotropy induced by cold rolling on duplex and super-austenitic stainless steels
No full textThis report contains the results obtained from the mechanical characterization tests carried out on
two different stainless steel (duplex 6%Ni, 22%Cr and super-austenitic 31%Ni, 28%Cr) used for the
manufacturing of pipes which are employed in the oil production.
The activity has been performed in order to evaluate the effects of anisotropy, induced by cold rolling, on the
mechanical characteristics of the investigated steels, measured in the three main directions.
Considering the small size of the component, the method and the specimens used for the tests were not the
standard one. The procedure carried out provided the strain measurement of the specimen during testing by
means of resistive strain gages, bonded on the specimens
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