The optimization problem of the shaped knife profiling

Проаналізовано переваги та недоліки процесу гарячого поділу безперервнолитої квадратної заготовки на ножицях з фасонними ножами. Відзначається доцільність проведення теоретичних досліджень розділових операцій на ножицях з використанням методу скінченних елементів (МСЕ). Метою даної роботи було визначення оптимальної форми профілювання фасонного ножа для поділу квадратної заготовки в гарячому стані шляхом математичного моделювання на базі МСЕ. Представлено методику проведення досліджень, що включали два етапи. На першому етапі використовували математичне моделювання відповідно до плану повного факторного експерименту 24 згідно виробничих умов реалізації процесу з ножами що мали значення кута розкриття ножів 90…98° та ухилу контактних поверхонь 3…11°. При обробці даних моделювання були отримані три відносних параметра, два з яких характеризують зминання (затяжка) і загин кінців розкату, і ще один – ромбічність торцевої поверхні. Для кожного з параметрів, отримані лінійні рівняння регресії як функція температури різання та розмірів заготовок, величини кута розкриття ножів та ухилу контактних поверхонь. На другому етапі дослідження вирішували оптимізаційну задачу пошуку мінімуму цільової функції – ромбічності. За результатами відзначено, що оптимальні значення профілювання ножів залежать від вимог, що висуваються до якості зрізу. Введено фактор граничного відхилення зминання і загину кінців, встановлений діапазон його значень та проаналізовано вплив на оптимальні параметри. Запропоновано величини кута розкриття ножів та ухилу контактних поверхонь, за умови мінімізації граничного відхилення зминання і загину кінців у досліджуваних діапазонах температур та розмірів заготовок. Отримано залежності параметрів профілювання ножів від граничного відхилення зминання і загину кінців заготовок після поділу. Результати роботи можуть бути рекомендовані для використання при прийнятті проектно-конструкторських і технологічних рішень в питаннях гарячого розділення безперервнолитої квадратної заготовки фасонними ножами на кут.The advantages and disadvantages of the process of separation in hot condition of billet with square shape by special profiled knives were analyzed. There is expediency of carrying out theoretical researches the separating operations by shears based on finite elements method (FEM) is noted. The purpose of the work was to determine the optimal shape for make form a profiled knife for separating a square billet in a hot state by simulating based on the FEM. A methodology of study realization consisting of two stages is presented. At the first stage, simulating was used in accordance with the plan of the full factorial experiment 24 according to the technological environment for the process implementation with knives having a knife opening angle of 90...98° and a contact surface inclination of 3...11°. At the processing the simulation results, three relative parameters were obtained. Two parameters characterize the crumpling (tightening) and bending of the billet ends, and one more – the rhomboidity of the end surface. For each of the parameters, the linear regression equations obtained as a function of cutting temperature and billet sizes, the knife opening angle and contact surface inclination. At the second stage of the study, the optimization problem of determining the minimum of the objective function – rhomboidity – was solved. According to the results, it was noted that the optimal values of the profiling of knives depend on the requirements for the quality of the cut. The factor of the maximum deviation of crumpling and bending of the ends is introduced. The range of its values is established and the influence on the optimal parameters is analyzed. The values of the knife opening angle and contact surface inclination are proposed, provided that the maximum deviation of the crumpling and bending of the ends, at the studied temperature ranges and sizes of the billets, is minimized. The dependences of the optimal parameters of the profiling of knives on the maximum deviation of the crumpling and bending of the ends of the billets after separation are obtained. Results of work can be recommended for use to get solutions in design and technology questions of hot separation square billet by profiled knife on the angle

TERRESTRIAL LASER SCANNER DATA TO SUPPORT COASTAL EROSION ANALYSIS: THE CONERO CASE STUDY

In this work a detailed TLS survey was carried out in summer 2012, in the Conero Regional Park (Marche, province of Ancona), along the "spiaggia San Michele" and "spiaggia Sassi Neri". These areas present several sections affected by erosion, rock falls and slope failures. They also belong to a very prestigious place for tourism during the summer season; therefore, deriving a risk map for these areas is really useful. Thanks to the TLS survey, it was possible to obtain a centimetre resolution DTM covering a reach of about 1.5 km of the coast. This high resolution DTM was used to derive some primary topographic attributes that allowed to arrange a preliminary discussion about the likely unstable areas. These topographic information and results will also serve as the reference point for future yearly TLS surveys, which will absolutely help in recognizing any micro changes and slope failures, improving the risk maps

Clinical significance of fluoroscopic patterns specific for the mitotic spindle in patients with reumatic diseases

Objective: we proposed to determine the clinical significance of anti-NuMA and anti-HsEg5 antibodies in a group of patients affected with rheumatic diseases. Materials and methods: indirect immunofluorescence on HEp-2000 cells at serum dilution of 1:40 was used to examin 26 sera which had previously showed a "mitotic spindle" fluoroscopic pattern type during laboratory routine. Results: 21 sera (80,7%) were identified with NuMA and 5 (19,3%) with HsEg5 patterns alone or associated with other ANA patterns. However only patients with isolated positiveness and that is 15 with NuMA and 4 with HsEg5 stainings were included in this study. Of the NuMA positive patients 5 were affected with arthropathies associated to different forms of thyroiditis, 2 with seronegative arthritis, 2 with antiphospholipid syndrome, 1 with systemic lupus erythematosus (SLE), 1 with rheumatoid arthritis, 1 with sicca syndrome, 1 with undifferentiated connective tissue disease, 1 with Mycoplasma pneumaniae infection and 1 with retinal thrombosis. Of the HsEg5 positive patients 3 were affected with SLE and 1 with seronegative arthritis. Conclusions: NuMA does not prevail in any defined rheumatic disease, while HsEg5 staining were more frequent (75%) in patients affected with SLE all of whom showing high antibody titres

Study of the Failure Mechanism of a High-Density Polyethylene Liner in a Type IV High-Pressure Storage Tank

The use of Type IV cylinders for gas storage is becoming more widespread in various sectors, especially in transportation, owing to the lightweight nature of this type of cylinder, which is composed of a polymeric liner that exerts a barrier effect and an outer composite material shell that primarily imparts mechanical strength. In this work, the failure analysis of an HDPE liner in a Type IV cylinder for high-pressure storage was carried out. The breakdown occurred during a cyclic pressure test at room temperature and manifested in the hemispherical head area, as cracks perpendicular to the liner pinch-off line. The failed sample was thoroughly investigated and its characteristics were compared with those of other liners at different stages of production of a Type IV cylinder (blow molding, curing of the composite material). An examination of the liner showed that no significant chemical and morphological changes occurred during the production cycle of a Type IV cylinder that could justify the liner rupture, and that the most likely cause of failure was a design-related fatigue phenomenon

Duplex ultrasound imaging alone is sufficient for midterm endovascular aneurysm repair surveillance: A cost analysis study and prospective comparison with computed tomography scan

ObjectiveEarly in our experience with endovascular aortic aneurysm repair (EVAR) we performed both serial computed tomography scans and duplex ultrasound (DU) imaging in our post-EVAR surveillance regimen. Later we conducted a prospective study with DU imaging as the sole surveillance study and determined cost savings and outcome using this strategy.MethodsFrom September 21, 1998, to May 30, 2008, 250 patients underwent EVAR at our hospital. Before July 1, 2004, EVAR patients underwent CT and DU imaging performed every 6 months during the first year and then annually if no problems were identified (group 1). We compared aneurysm sac size, presence of endoleak, and graft patency between the two scanning modalities. After July 1, 2004, patients underwent surveillance using DU imaging as the sole surveillance study unless a problem was detected (group 2). CT and DU imaging charges for each regimen were compared using our 2008 health system pricing and Medicare reimbursements. All DU examinations were performed in our accredited noninvasive vascular laboratory by experienced technologists. Statistical analysis was performed using Pearson correlation coefficient.ResultsDU and CT scans were equivalent in determining aneurysm sac diameter after EVAR (P < .001). DU and CT were each as likely to falsely suggest an endoleak when none existed and were as likely to miss an endoleak. Using DU imaging alone would have reduced cost of EVAR surveillance by 29% ($534,356) in group 1. Cost savings of$1595 per patient per year were realized in group 2 by eliminating CT scan surveillance. None of the group 2 patients sustained an adverse event such as rupture, graft migration, or limb occlusion as a result of having DU imaging performed as the sole follow-up modality.ConclusionSurveillance of EVAR patients can be performed accurately, safely, and cost-effectively with DU as the sole imaging study

AB0378 UPGRADING THERAPY STRATEGY IMPROVES PREGNANCY OUTCOME IN ANTIPHOSPHOLIPID SYNDROME: A COHORT MANAGEMENT STUDY

Background:While it is generally agreed that pregnant APS patients should receive personalized treatment, evidence-based guidelines for these patients continue to be lacking.Objectives:The current study was designed as a management cohort study aiming to evaluate the efficacy and safety of different treatment strategies for pregnant APS patients in the attempt to provide some practical suggestions for attending physicians.Methods:One-hundred-twenty-seven consecutive pregnancies were assessed; 87 (68.5%) with a history of pregnancy morbidity alone were treated with prophylactic low molecular weight heparin (LMWH)+low-dose aspirin (LDA, 100 mg) [Group I] and 40 (31.5%) with a history of thrombosis and/or severe pregnancy complications with therapeutic LMWH+LDA [Group II]. LMWH doses were increased throughout the pregnancies depending on the patients' weight gain, and treatment was switched to a more intensive one at the first sign of maternal/fetal complications. The study's primary outcome was live births.Results:There were no significant differences in live birth rate between Group I (95.4%) and Group II (87.5%). Even, fetal complication rate was similar in the two groups; the Group II nevertheless had a higher prevalence of maternal and neonatal complications (p=0.0005 and p=0.01, respectively) and registered a significantly lower gestational age at delivery and birth weight (p=0.0001 and p=0.0005, respectively). Two patients in Group I switched to Group II therapy, six patients in Group II switched to a more intensive treatment strategy (weekly plasma exchange+ fortnightly intravenous immunoglobulins in addition to therapeutic LMWH+LDA). Comparison of the clinical and laboratory characteristics between patients who had shifted to a more intensive therapy and those who did not showed a significant prevalence of history of thrombosis ± pregnancy morbidity (p=0.02, OR 5.96, 95% CI 1.33-26.62) previous pregnancy complications (p=0.02, OR 8.32, 95% CI 1.67-41.3), triple aPL positivity (p <0.0001, OR 97.13, 95% CI 10.6-890) and pregnancy complications (p<0.0001, OR 197,7, 95% CI 10.57-3699) in upgrading group, instead single aPL positivity significantly prevailed (p=0.003, OR 0.06, 95% CI 0.008-0.58) in non-upgrading group. Logistic regression analysis demonstrated that triple aPL positivity was an independent factor for switching to a more effective therapy protocol (p <0.0001, OR 98, 95% CI 10.7-897.54). All eight switched patients achieved a live birth.Conclusion:Using adjusted LMWH doses and upgrading therapy at the first signs of pregnancy complications led to a high rate of live births in a relatively large group of APS patients. The study outlines the criteria for prescribing appropriate therapy for various subsets of these patients and for switching/upgrading the treatment protocol when it is no longer sufficient. Unfortunately, for the moment there are no evidence-based guidelines on the ideal additional treatment in refractory to conventional therapy APS patients. The present results will hopefully help point the direction of future clinical trials investigating the efficacy and safety of the different therapies on large numbers of APS pregnant patients in order to identify the benefits and limits of different treatment strategies administered from the beginning of pregnancy.Disclosure of Interests:Ariela Hoxha Speakers bureau: Celgene, UCB, Novartis, Sanofi, Werfen, Maria Favaro: None declared, Antonia Calligaro: None declared, Teresa Del Ross: None declared, Alessandra Teresa Ruffatti: None declared, Chiara Infantolino: None declared, Marta Tonello: None declared, Elena Mattia: None declared, Amelia Ruffatti: None declare

X-ray and Infrared Microanalyses of <i>Mona Lisa</i>'s Ground Layer and Significance Regarding Leonardo da Vinci's Palette

An exceptional microsample from the ground layer of Leonardo da Vinci's Mona Lisa was analyzed by high-angular resolution synchrotron X-ray diffraction and micro Fourier transform infrared spectroscopy, revealing a singular mixture of strongly saponified oil with high lead content and a cerussite (PbCO3)-depleted lead white pigment. The most remarkable signature in the sample is the presence of plumbonacrite (Pb5(CO3)3O(OH)2), a rare compound that is stable only in an alkaline environment. Leonardo probably endeavored to prepare a thick paint suitable for covering the wooden panel of the Mona Lisa by treating the oil with a high load of lead II oxide, PbO. The review of Leonardo's manuscripts (original and latter translation) to track the mention of PbO gives ambiguous information. Conversely, the analysis of fragments from the Last Supper confirms that not only PbO was part of Leonardo's palette, through the detection of both litharge (α-PbO) and massicot (β-PbO) but also plumbonacrite and shannonite (Pb2OCO3), the latter phase being detected for the first time in a historical painting.</p

Ultra low threshold current THz quantum cascade lasers based on buried strip-waveguides

THz quantum cascade lasers based on a novel buried cavity geometry are demonstrated by combining double-metal waveguides with proton implantation. Devices are realised with emission at 2.8 THz, displaying ultra low threshold currents of 19 mA at 4K in both pulsed and continuous wave operation. Thanks to the semiconductor material on both sides of the active region and to the narrow width of the top metal strip, the thermal properties of these devices have been greatly improved. A decrease of the thermal resistance by over a factor of two compared to standard ridge double-metal lasers of similar size has been measured.Comment: 10 pages, 3 figures. Submitted for publication to Applied Physiscs Letters (February 2005