CAD-CAE methods to support restoration and museum exhibition of bronze statues: the “Principe Ellenistico”

Ancient bronze statues mainly require material integrity assessment and restoration. Restoration may include also the update of the museum exhibition, defining new structural frames and fragment re-composition to preserve the statue and improve the interpretation of the original aspect. This paper proves how engineering methods (such as Finite Element Analysis, Computer Aided Design modelling, Reverse Engineering) may assist cultural heritage experts and restorers in these tasks. It presents the activities made together with the Museo Nazionale Romano and the Istituto Superiore per la Conservazione e il Restauro, on the so-called “Principe Ellenistico” (Hellenistic Prince). This bronze was found in pieces (body, left arm and right leg), at the end of 19th century during an excavation made in Rome. No visual or reference sources can say its origin and its final posture was defined by restorers at the end of the 19th century according to their hypothesis and studies. In the 20th century, a further restoration was made on the critical areas of the surface, together with some structural improvement of the inner frame. Nowadays, after a review of its position inside the Museum, new experimental and numerical analyses have been carried out to better understand surface weakness and correct left arm positionin

Virtual prototyping of medieval weapons for historical reconstruction of siege scenarios starting from topography and archaeological investigations

Chronicles of sieges to castles or fortresses, using “machinae”, can often be found in historical sources. Moreover, archaeological excavations of castles or fortresses has brought to light rocks or projectiles whose carving suggests a military usage. Nevertheless, chronicles and discoveries alone, are seldom enough to propose a faithful reconstruction of these machines. Therefore, the aim of this research is the development of methodologies for reconstructing virtual scenarios of sieges, starting from the scarce information available. In order to achieve it, a procedure for the virtual reconstruction of the siege machine has been set up, focusing on typology and dimensions of the machines, also investigating possible fire positions according to topography. The entire procedure has been developed using the siege of Cervara di Roma’s Rocca as a case study. Late medieval chronicles (end of 13th Century) report the siege brought by the papal army in order to restore the jurisdiction on the Cervara’s stronghold, following the insurrection of a group of vassals headed by a monk named Pelagio. The discovery, in the area of the Rocca, of a stone that could have been used as a projectile confirms what reported. The proposed methodology is composed of two parts. The first one is connected to the study of the “internal ballistics”, to understand the performances and to build virtual models of siege machines. The second part is the study of the “external ballistics”, then to the positioning and shooting ability of possible machines, analysing the topography of the area. In this paper, we present the feasibility of this methodology through the preliminary results achieved correlating internal and external ballistics

Comparison of algorithms for recognition of cylindrical features in a voxel-based approach for tolerance inspection

In injection molding production, automatic inspections are needed to control defects and evaluate the assigned functional tolerances of components and dies. With the “Smart Manufacturing” approach as a point of view, this paper resumes part of a wider research aiming the integration and the automation of a Reverse Engineering inspection process in components and die set-up. The paper compares two fitting approaches for recognition of portions of cylindrical surfaces. Therefore, they are evaluated in the respect of an automatic voxel-based feature recognition of 3D dense cloud of points for tolerance inspection of injection-molded parts. The first approach is a 2D Levenberg Marquardt algorithm coupled with a first guess evaluation made by the Kasa algebraic form. The second one is a 3D fitting based on the RANdom SAmple Consensus algorithm (RANSAC). The evaluation has been made according to the ability of the approaches of working on points associated to the voxel structure that locally divides the cloud to characterize planar and curved surfaces. After the presentation of the overall automatic recognition, the cylindrical surface algorithms are presented and compared trough test cases

Robust die compensation in sheet metal design through the integration of dual response surface and shape function optimization

In sheet metal forming, springback represents a major drawback increasing die set-up problems, especially for ultra-high strength steels. Finite Element Analysis is a well-established method to simulate the process during design, and multicriteria optimizations, for example, via surrogate models, are investigated in order to develop integrated design. Since to take into account also springback compensation die design may involve a large number of geometric variables, this paper presents a robust design formulation, based on the adoption of the shape function optimization, to describe springback in terms of weights directly associated to global shape variations of the die shape. Doing so, multicriteria optimization, which involves also die compensation, can be set up in a more intuitive approach, as requested in the preliminary steps of die design. After the introduction of the industrial problem, the mathematical formulation of the shape function optimization is presented together with its novel extension to Robust Design, which is based on the Dual Response Surface. Through a test case derived from the head part of a B-pillar, stamped from a Dual Phase sheet 1.5 mm thick, this novel extension investigates the effect of 6% variation from nominal values of initial yield stress and thickness. Results demonstrate the feasibility of the procedure, underlying that an optimal compensation may not be optimal in terms of process robustness

Epidemiology and Surgical Management of Foreign Bodies in the Liver in the Pediatric Population: A Systematic Review of the Literature

Retention of foreign bodies (FB) in the liver parenchyma is a rare event in children but it can bring a heavy burden in terms of immediate and long-term complications. Multiple materials can migrate inside the liver. Clinical manifestations may vary, depending on the nature of the foreign body, its route of penetration and timing after the initial event. Moreover, the location of the FB inside the liver parenchyma may pose specific issues related to the possible complications of a challenging surgical extraction. Different clinical settings and the need for highly specialized surgical skills may influence the overall management of these children. Given the rarity of this event, a systematic review of the literature on this topic was conducted and confirmed the pivotal role of surgery in the pediatric population

Epidemiology and Surgical Management of Foreign Bodies in the Liver in the Pediatric Population: A Systematic Review of the Literature

Retention of foreign bodies (FB) in the liver parenchyma is a rare event in children but it can bring a heavy burden in terms of immediate and long-term complications. Multiple materials can migrate inside the liver. Clinical manifestations may vary, depending on the nature of the foreign body, its route of penetration and timing after the initial event. Moreover, the location of the FB inside the liver parenchyma may pose specific issues related to the possible complications of a challenging surgical extraction. Different clinical settings and the need for highly specialized surgical skills may influence the overall management of these children. Given the rarity of this event, a systematic review of the literature on this topic was conducted and confirmed the pivotal role of surgery in the pediatric population

prenatal diagnosis and surgical innovations in congenital diaphragmatic hernia evaluation of pre and post operative management

Introduction. Congenital diaphragmatic hernia (CDH) is still today considered a challenge from surgeons. Considerable progress in prenatal diagnosis, intensive care unit of neonates and surgical techniques, with the possibility to perform minimally access surgery, widely increased survival rates. The aim of this study is to analyze our series about long and short-term outcomes, also considering the progress made by minimally invasive techniques. Methods. The study was performed at Pediatric Surgery of Siena. It is a retrospective study that analyzed all patients with CDH (Bochdalek) treated in the last 14 years, from 2000 to 2013. Sex, side of the defect, presence of prenatal diagnosis, age of onset and symptoms, associate malformation, herniated organs, surgical technique and site of surgery, complications, recurrences, survival and followup were analyzed. Results. We included 23 patients. Five of them, were ruled out because of affected by diaphragmatic eventration or acquired diaphragmatic hernia. Forteen patients (77%) presented left CDH and 4 patients (23%) a right one. The male female ratio were 14:4. Prenatal diagnosis was performed in 5 patients (27,5%) at a mean gestational age of 29 weeks. Forteen patients (77%) had an early onset of symptoms (first day of life). Most common symptoms were respiratory distress and cyanosis; 4 patients (23%) had a late onset of symptoms, at a mean age of 9 months, and most common symptoms were failure to thrive and vomiting. Seven patients (39%) had associated malformation: common mesenterium (5 pts-71%). The colon was the most commonly herniated organ, present in 15 patients (83%), followed by small intestine in 13 patients (72%), stomach in 11 patients (61%), spleen in 9 patients (50%) and liver in 4 patients (23%). Seventeen patients (94,5%) underwent open surgery: 10 of them (59%) underwent a subcostal laparotomy approach, 7 of them (41%) underwent a supraumbelical laparotomy approach; 1 patient (5%) underwent minimally access surgery with thoracoscopy access. We performed performed surgery in the intensive care unit in 3 patients (16,5%). Six patients (33%) developed minor postoperatory complications. No patient had recurrence. Four patients died so we report a mortality rate of 23%. A follow-up investigation, with an average duration of 87 months, it is still going on in 5 patients (27,5%). Conclusions. The our survival rate was 77% and it reflects the encouraging reported data in the recent literature. These results are due to the reliability of the new resuscitation strategies, such as high-frequency oscillatory ventilation and the use of NO, the ability to perform surgery in the neonatal intensive care unit and, especially, to successfully perform minimally invasive surgery in newborn. The improvement of the survival showed the increasing of long-term morbidity end the requirement of a multidisciplinary followup. For these reasons, a multidisciplinary pathway for the management of young patients has been created, to follow them in a standardized way as early as the prenatal diagnosis

Improved prediction for layered predictive animated mesh compression

In this paper, we deal with layered predictive compression of animated meshes represented by series of 3D static meshes with same connectivity. We propose two schemes to improve the prediction. First improvement is using weighted spatial prediction rather than averaging neighbor vertices. The second improvement is a novel predictor based on rotation angle of incident triangles in current and previous frames. The experimental results show that around 6- 10 % bitrate reduction can be achieved by replacing the spatial prediction in the reference coder with the proposed weighted spatial prediction and 9- 18 % bitrate reduction is possible with the proposed angle based predictor using weighted spatial prediction, depending on the content and quantization level