Modeling assumptions influence on stress and strain state in 450 t cranes hoisting winch construction

This work investigates the FEM simulation of stress and strain state of the selected trolley’s load-carrying structure with 450 tones hoisting capacity [1]. Computational loads were adopted as in standard PN-EN 13001-2. Model of trolley was built from several cooperating with each other (in contact) parts. The influence of model assumptions (simplification) in selected construction nodes to the value of maximum stress and strain with its area of occurrence was being analyzed. The aim of this study was to determine whether the simplification, which reduces the time required to prepare the model and perform calculations (e.g., rigid connection instead of contact) are substantially changing the characteristics of the model

Selection of torsional vibration damper based on the results of simulation

So far in engineering practice torsional and transverse vibration damping characteristics of the rotating systems were selected independently. This has resulted from the use of linearized equations of motion in calculations. Linearization results in the loss of information on the coupling between vibration. Currently, increase of the technical requirements to the rotating systems makes it necessary to conduct research in the non-linear range. Because the appropriate analytical methods for determining the form and frequency of vibrations in nonlinear systems are currently under development, simulation methods and analysis solutions in the time domain are growing in importance. In case of task consisting of selection an adequate torsional vibration damper, it is necessary to repeat the simulation calculations for the selected set of parameters, which is very time consuming and is a major drawback of this method. The aim of presented in the work simulation studies was a choice of such a torsional vibration damper, which also would reduce lateral vibration amplitude. The Matlab-Simulink environment and the library of Simulink blocks developed by authors and intended to model rotating systems, in any configuration, was used. Known in the literature the dynamic model of a broadband torsional vibration damper has been implemented in a form of an additional block of the above-recited library

Simplified method of modelling the bearing supports in rotating systems

Study of the rotating system dynamics by numerical methods requires an appropriate modeling of cooperation of shaft with bearings. The choice of method of modeling the bearing supports of shaft may have a significant impact both on the results obtained and the time needed to complete the simulation. The paper proposes a simplified way of modeling the bearing supports in rotating systems. The proposed modeling methodology is applied in the author’s library of Simulink blocks, which is dedicated to the research of simulation of rotating systems in transient states and in the presence of various types of non-linearity. The main purpose of applied simplifications is acceleration of simulation calculations while maintaining sufficient accuracy. The results of the simulation are presented on chosen example

Structure of the Extruded and Thermally Treated Ni54.3Fe16.2Ga29.5 Alloy

Hot extrusion process was applied to Ni54:3Fe16:2Ga29:5 polycrystalline alloy. Then the rod was annealed subsequently for 1 h at 700, 800, 900, and 1100 C. In this paper the effect of annealing on the microstructure of the polycrystalline extruded Ni–Fe–Ga alloy were analyzed. The structure of the alloys was determined by the X-ray and transmission electron microscopy. The electron backscattering diffraction technique was applied to obtain the texture of the extruded rods after heat treatmen

Trigone ventricular meningiomas — clinical characteristics, histopathology and results of surgical treatment

Aim of the study. Intraventricular meningiomas (IVMs) are rare tumours accounting for 0.5–3.0% of all meningiomas. IVMs require different surgical approaches and preparation in deep brain areas. The aim of our study was to present the clinico- -histopathological characteristics and treatment outcomes of trigone IVMs in a series of 15 patients. Materials and methods. Eight women and seven men (mean age 52) with 15 trigone IVMs were retrospectively analysed. Patients presented with headache (47%), psychoorganic syndrome (40%), hemianopsia (33%) or paresis (20%), including three (20%) patients with Karnofsky Performance Scale (KPS) < 80. Mean tumour size was 55.2 mm (range: 30–100 mm). Results. Gross total tumour resection was performed in 14 (93%) cases, and subtotal in one (7%). A new deficit appeared in 83% (5/6) following a transparietal approach, in 14% (1/7) following a transtemporal approach, and in none of two patients following a transoccipital approach. Postoperative complications occurred in six (40%) patients; no patient died, but in two (13%) the new deficit was permanent. Tumour re-growth was found in two (13%) patients after 14 and 31 months. Meningiomas of WHO grade I occurred in 12, grade II in three, and grade III in one tumour recurrence. In long-term follow-up (mean: 60.8 months), including the results of revision operations, KPS: 80–100 was in 13 (87%) patients, KPS: 50 in one (severe hemiparesis after revision) and one patient was lost to follow-up (KPS: 100 on discharge). Conclusions. 20% of IVMs in our series were atypical. The results of surgery for IVMs, although satisfactory in general, require further improvement by reducing the rate of focal deficits resulting from a surgical approach

Numerical identification of the overhead travelling crane’s dynamic factor caused by lifting the load off the ground

Overhead travelling cranes work with intermittent motion, and therefore are most exposed to dynamic loads. In steel constructions, as a result of load pick up from the ground, vibrations of various degrees of intensity are induced, which should be included in crane design. These loads affect both the hoisting mechanisms and load-carrying structures. The aim of this study is the formulation of a phenomenological model of an overhead travelling crane enabling the identification of dynamic factors caused by lifting the load off the ground. The object of the study was 107 overhead travelling cranes with lifting capacities from 5 to 50 tones, designed in the Centre for Research and Development of Cranes and Transport Equipment “Detrans” in Bytom and produced in Poland in the period 1970-2005. Cranes were classified according to the stiffness classes proposed in European standards for crane safety. In this paper, computer simulations are carried out on the basis of a phenomenological model with four degrees of freedom, three of them corresponding to the crane’s structure and one to the hoisted load. The model also allows assumption of the variable stiffness and damping of the steel rope during its shortening. The values of the dynamic factors refer to the various design and dynamic parameters of overhead travelling cranes, formulating appropriate conclusions

Numerical identification of the overhead travelling crane’s dynamic factor caused by lifting the load off the ground

Overhead travelling cranes work with intermittent motion, and therefore are most exposed to dynamic loads. In steel constructions, as a result of load pick up from the ground, vibrations of various degrees of intensity are induced, which should be included in crane design. These loads affect both the hoisting mechanisms and load-carrying structures. The aim of this study is the formulation of a phenomenological model of an overhead travelling crane enabling the identification of dynamic factors caused by lifting the load off the ground. The object of the study was 107 overhead travelling cranes with lifting capacities from 5 to 50 tones, designed in the Centre for Research and Development of Cranes and Transport Equipment “Detrans” in Bytom and produced in Poland in the period 1970-2005. Cranes were classified according to the stiffness classes proposed in European standards for crane safety. In this paper, computer simulations are carried out on the basis of a phenomenological model with four degrees of freedom, three of them corresponding to the crane’s structure and one to the hoisted load. The model also allows assumption of the variable stiffness and damping of the steel rope during its shortening. The values of the dynamic factors refer to the various design and dynamic parameters of overhead travelling cranes, formulating appropriate conclusions

Amiodarone and the thyroid

Lek antyarytmiczny — amiodaron, pochodna benzofuranu bogata w jod, wywołuje zaburzenia funkcji tarczycy w 15–20% przypadków. Amiodaron może powodować niedoczynność tarczycy (AIH) oraz nadczynność tarczycy (AIT). AIH jest leczona substytucyjnie lewotyroksyną, w jej przypadku nie jest konieczne odstawienie amiodaronu. Nadczynność tarczycy indukowaną amiodaronem dzielimy na dwa typy: typ 1 — nadczynność tarczycy związana z nadmierną produkcją hormonów tarczycowych, oraz typ 2, w której dominuje proces zapalenia tarczycy związanego z rozpadem gruczołu. Wyróżnia się również typ mieszany/nieokreślony, w którego patomechanizmie udział biorą oba powyżej opisane mechanizmy. Typ 1 AIT występuje zwykle na podłożu wcześniej występującej choroby tarczycy, zaś typ 2 w pierwotnie zdrowym gruczole tarczowym. Tionamidy są lekiem pierwszego rzutu w leczeniu typu 1 AIT, nadchloran sodowy/potasowy poprzez hamowanie wychwytu jodu może zwiększać odpowiedź na tionamidy. AIT typu 2 jest leczone głównie z zastosowaniem glikokortykosteroidów. Odpowiedź na leczenie zależy od wielkości gruczołu tarczowego i ciężkości tyreotoksykozy. Postaci mieszane mogą wymagać zastosowania złożonej terapii z użyciem tionamidów, nadchloranu sodowego/potasowego oraz steroidów. Leczenie radiojodem często jest niemożliwe z powodu zmniejszonego wychwytu jodu u pacjentów wcześniej leczonych amiodaronem. Zabieg usunięcia tarczycy jest bardzo pomocną formą leczenia nadczynności tarczycy indukowanej jodem, szczególnie w przypadkach opornych na leczenie farmakologiczne. Tyroidektomia wykonana przez doświadczony zespół chirurgów może być szczególnie pomocna u chorych z poważnymi zaburzeniami w układzie sercowo-naczyniowym. (Endokrynol Pol 2015; 66 (2): 176–196)Amiodarone, a benzofuranic iodine-rich antiarrhythmic drug, causes thyroid dysfunction in 15–20% of cases. Amiodarone can cause both hypothyroidism (AIH, amiodarone-induced hypothyroidism) and thyrotoxicosis (AIT, amiodarone-induced thyrotoxicosis). AIH is treated by L-thyroxin replacement and does not need amiodarone discontinuation. There are two main forms of AIT: type 1, a form of true iodineinduced hyperthyroidism; and type 2, a drug-induced destructive thyroiditis. However, mixed/indefinite forms exist, contributed to by both pathogenic mechanisms. Type 1 AIT usually occurs in diseased thyroid glands, whereas type 2 AIT develops in substantially normal thyroid glands. Thioamides represent the first-line treatment for type 1 AIT, but iodine-replete glands are poorly responsive; sodium/potassium perchlorate, by inhibiting thyroidal iodine uptake, may increase the response to thioamides. Type 2 AIT is best treated by oral glucocorticoids. Response depends on thyroid volume and severity of thyrotoxicosis. Mixed/indefinite forms may require a combination of thioamides, potassium perchlorate, and steroids. Radioiodine treatment is usually not feasible because amiodarone-related iodine load decreases thyroidal radioiodine uptake. Thyroidectomy represents an important and helpful option in cases resistant to medical therapy. Surgery performed by a skilled surgeon may represent an emergent treatment in patients who have severe cardiac dysfunction. (Endokrynol Pol 2015; 66 (2): 176–196

Mutations in the von Hippel-Lindau Tumour Suppressor Gene in Central Nervous System Hemangioblastomas

Central nervous system hemangioblastomas (cHAB) are rare tumours which most commonly arise in the cerebellum. Most tumours are sporadic, but as many as one third of cHABs occur in the course of the hereditary disorder - von Hippel-Lindau disease (VHL). In order to diagnose new VHL families in Poland we performed sequencing of the entire VHL gene in archival material (paraffin embedded hemangioblastoma tissues) in a large series of 203 unselected patients with cHAB. VHL gene mutations were detected in 70 (41%) of 171 tumour samples from which DNA of relatively good quality was isolated. We were able to obtain blood samples from 19 of mutation positive cases. Eight (42%) of these harboured germline mutations in persons from distinct undiagnosed VHL families

The significant impact of age on the clinical outcomes of laparoscopic appendectomy : results from the Polish Laparoscopic Appendectomy multicenter large cohort study

Acute appendicitis (AA) is the most common surgical emergency and can occur at any age. Nearly all of the studies comparing outcomes of appendectomy between younger and older patients set cut-off point at 65 years. In this multicenter observational study, we aimed to compare laparoscopic appendectomy for AA in various groups of patients with particular interest in the elderly and very elderly in comparison to younger adults. Our multicenter observational study of 18 surgical units assessed the outcomes of 4618 laparoscopic appendectomies for AA. Patients were divided in 4 groups according to their age: Group 1- 8 days. Logistic regression models comparing perioperative results of each of the 3 oldest groups compared with the youngest one showed significant differences in odds ratios of symptoms lasting >48hours, presence of complicated appendicitis, perioperative morbidity, conversion rate, prolonged LOS (>8 days). The findings of this study confirm that the outcomes of laparoscopic approach to AA in different age groups are not the same regarding outcomes and the clinical picture. Older patients are at high risk both in the preoperative, intraoperative, and postoperative period. The differences are visible already at the age of 40 years old. Since delayed diagnosis and postponed surgery result in the development of complicated appendicitis, more effort should be placed in improving treatment patterns for the elderly and their clinical outcome