Controlled Deflection Approach for Rotor Crack Detection

Atransverse shaft crack is a serious malfunction that can occurdue to cyclic loading, creep, stress corrosion, and other mechanismsto which rotating machines are subjected. Though studied for manyyears, the problems of early crack detection and warning arestill in the limelight of many researchers. This is dueto the fact that the crack has subtle influence onthe dynamic response of the machine and still there areno widely accepted, reliable methods of its early detection. Thispaper presents a new approach to these problems. The methodutilizes the coupling mechanism between the bending and torsional vibrationsof the cracked, nonrotating shaft. By applying an external lateralforce of constant amplitude, a small shaft deflection is induced.Simultaneously, a harmonic torque is applied to the shaft inducingits torsional vibrations. By changing the angular position of thelateral force application, the position of the deflection also changesopening or closing of the crack. This changes the waythe bending and torsional vibrations are being coupled. By studyingthe coupled lateral vibration response for each angular position ofthe lateral force one can assess the possible presence ofthe crack. The approach is demonstrated with a numerical modelof a rotor. The model is based on the rigidfinite element method (RFE), which has previously been successfully appliedfor the dynamic analysis of many complicated, mechanical structures. TheRFE method is extended and adopted for the modeling ofthe cracked shafts. An original concept of crack modeling utilizingthe RFE method is presented. The crack is modeled asa set of spring-damping elements (SDEs) of variable stiffness connectingtwo sections of the shaft. By calculating the axial deformationsof the SDEs, the opening/closing mechanism of the crack isintroduced. The results of numerical analysis demonstrate the potential ofthe suggested approach for effective shaft crack detection

Auxiliary State Variables for Rotor Crack Detection

In the present study, a new model-based method for rotor crack detection and crack location is proposed. The finiteelement model of the rotor-bearing system accounts for the breathing mechanism of the crack. The model of the rotor system is augmented with an auxiliary single-degree-of-freedom oscillator. The observer is designed and the estimates of its two auxiliary state variables are proposed as crack indicators. The crack location along the shaft is determined by designing a set of observers, which calculate the values of these indicators for different possible crack locations along the shaft. The proposed method is validated numerically and the results prove its capability to detect and locate the crack. Further study will include experimental and numerical investigations to make the approach more robust

Investigation of an Advanced Cellulose Profile Used for the Manufacture of Gating Systems

The herein paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure

Network Management in Non-classified Data Hiding System Using Master Resident over Hidden Layer, Journal of Telecommunications and Information Technology, 2011, nr 1

The paper presents a practical implementation of the non-classified data hiding system (NDHS) understood asa military platform for information warfare that takes advantage of the hidden data transmission for voice connections inorder to gain informational lead over a potential enemy. The NDHS performs here as a botnet network that is managedby the hidden transmission controller referred to as the master resident. Research studies are dedicated to investigationof various connections in heterogeneous links as well as functionalities of such components as hidden protocol bridges andthe master resident

Current treatment options for advanced choriocarcinoma on the basis of own case and review of the literature

Choriocarcinoma is one of rare neoplasms of female reproductive organs. In the last decade only a few cases of this disease have been registered in Poland. The paper presents the current principles of diagnosis and treatment options for this rare disease based on the authors’ clinical experience (description of the case) and literature review. This paper provides basic information on epidemiology, FIGO classification, and also discusses the chemotherapy regimens used in the medical treatment of choriocarcinoma. Surgical options were also considered. A thematic review of the most important papers published in international journals in recent years has also been made

Activity of the thyroid parafollicular (C) cells in simple and hyperactive nodular goitre treated surgically - preliminary investigations

The aim of this study was to evaluate the significance of measuring calcitonin (CT) plasma concentrations in patients with simple and hyperthyroid goitre treated surgically. Eighty four patients who underwent operations during the years 2000-2002 were analysed. Plasma concentrations of CT were determined by commercially available radioimmunoassay on the day of hospitalisation. Elevated concentrations of CT were found in 8 patients: in 5 out of 26 (19.2%) and in 3 out of 33 (9.0%) patients with Graves’ disease and with multinodular goitre, respectively. No major differences in concentrations of CT were observed in patients with simple goitre. Postoperative morphological analysis of pathologically changed hyperactive thyroids showed the presence of enlarged C cells distributed either in small groups or even singly with weakening immunohistochemical reaction for CT. These observations may point to the possibility of a relationship between the functional state of the thyroid gland and the activity of C cells

Alteration of parafollicular (C) cells activity in the experimental model of hypothyroidism in rats.

Our previous study has shown the alteration of C cells activity in rats with experimental model of hyperthyroidism. The aim of the present study was the evaluation of parafollicular cells activity in rats with hypothyroidism evoked by propylthiouracil (PTU) given in drinking water over 21 days. Histological, ultrastructural and immunocytochemical studies using specific antibodies against calcitonin and CGRP were performed on thyroid glands taken from experimental and control groups of rats. Moreover, in all animals the calcitonin plasma levels were evaluated by radioimmunoassay. After chronic administration of PTU, thyroid image showed predominant microfollicular hyperplasia and attenuated density of parafollicular cells. The intensity of immunocytochemical reactions for CT and CGRP were weaker in the majority of C cells in comparison to the control rats, in which strong immunocytochemical reaction was observed. Examination in the electron microscope reveals the features of hypoactivity both in follicular and parafollicular cells, in which the quantity and electron density of secretory granules were smaller in comparison to the control group. These microscopic changes were accompanied by a significant decrease of calcitonin plasma concentration. Alteration of C cells activity in the experimental model of hypothyroidism, accompanied by microfollicular hypertrophy, may point to the mutual cooperation between parafollicular and follicular cells

Detecting Cracked Rotors Using Auxiliary Harmonic Excitation

Cracked rotors are not only important from a practical and economic viewpoint, they also exhibit interesting dynamics. This paper investigates the modelling and analysis of machines with breathing cracks, which open and close due to the self-weight of the rotor, producing a parametric excitation. After reviewing the modelling of cracked rotors, the paper analyses the use of auxiliary excitation of the shaft, often implemented using active magnetic bearings to detect cracks. Applying a sinusoidal excitation generates response frequencies that are combinations of the rotor spin speed and excitation frequency. Previously this system was analysed using multiple scales analysis; this paper suggests an alternative approach based on the harmonic balance method, and validates this approach using simulated and experimental results. Consideration is also given to some issues to enable this approach to become a robust condition monitoring technique for cracked shafts

Carcinoid of the small intestine as a rare cause of gastrointestinal bleeding diagnosed with angio-CT examination of the abdominal cavity - case report

In this report a rare case of a bleeding carcinoid located in the ileum and diagnosed with an angio-CT examination of the abdominal cavity is presented. An angio-CT examination of the abdominal cavity may be an effective method of imaging diagnostics in cases of negative results of endoscopy and colonoscopy examinations and, at the same time, a shortage of accessibility to double-balloon enteroscopy and capsule endoscopy. It is possible to visualize bleeding lesions on condition that the outflow of the blood into the digestive tract is above 1 ml per minute. The patient concerned was operated on in a scheduled course following proper preparation. The perioperative course was uneventful and after a three-year follow-up no features of the recurrence of neoplastic disease have been observed.W pracy przedstawiono rzadki przypadek krwawiącego rakowiaka jelita krętego rozpoznanego przy użyciu angio-TK jamy brzusznej. Przy ujemnym wyniku panendoskopii i kolonoskopii oraz braku dostępności enteroskopii dwubalonowej bądź kapsułki endoskopowej, angio-TK jamy brzusznej może być skuteczną metodą diagnostyki obrazowej. Warunkiem uwidocznienia krwawiącej zmiany jest zachowany wypływ krwi do przewodu pokarmowego powyżej 1 ml/min. Po przygotowaniu pacjentkę zoperowano w trybie planowym. Przebieg okołooperacyjny był niepowikłany, a po trzyletnim okresie obserwacji nie stwierdzono cech wznowy choroby nowotworowej

The role of objective and subjective factors in cancer-related fatigue syndrome: a pilot study in advanced cancer patients receiving palliative radiotherapy treatment

Background. Cancer-related fatigue is observed in most cancer patients in advanced stage of the disease. It may be caused by both, the disease and treatment - chemotherapy and radiotherapy. During and after palliative radiotherapy treatment, whose objective is to improve patient's quality of life, increase of fatigue might occur. The aims of this study were both to assess the level of fatigue in patients receiving palliative radiotherapy and to determine the role of psychological variables in cancer-related fatigue syndrome e.g. the relation between temperament and cancer-related fatigue, as well as strategies of coping with disease. Method. 24 patients in advanced or metastatic cancer, undergoing palliative radiotherapy participated in the study. Prior to and after the treatment the patients were asked to complete a series of psychological questionnaires, like temperament questionnaire (FCZ-KT), Mini-MAC, PRE. Physicians, before and after the treatment, completed medical questionnaire, in which objective parameters of chronic fatigue syndrome were monitored (e.g. Haemoglobin level). Results. Results show correlation between temperament and strategies of coping with disease with the level of fatigue. Psychological features may constitute a predictor for the fatigue level. Because of the group size this study has pilot and explorative character.Background. Cancer-related fatigue is observed in most cancer patients in advanced stage of the disease. It may be caused by both, the disease and treatment - chemotherapy and radiotherapy. During and after palliative radiotherapy treatment, whose objective is to improve patient's quality of life, increase of fatigue might occur. The aims of this study were both to assess the level of fatigue in patients receiving palliative radiotherapy and to determine the role of psychological variables in cancer-related fatigue syndrome e.g. the relation between temperament and cancer-related fatigue, as well as strategies of coping with disease. Method. 24 patients in advanced or metastatic cancer, undergoing palliative radiotherapy participated in the study. Prior to and after the treatment the patients were asked to complete a series of psychological questionnaires, like temperament questionnaire (FCZ-KT), Mini-MAC, PRE. Physicians, before and after the treatment, completed medical questionnaire, in which objective parameters of chronic fatigue syndrome were monitored (e.g. Haemoglobin level). Results. Results show correlation between temperament and strategies of coping with disease with the level of fatigue. Psychological features may constitute a predictor for the fatigue level. Because of the group size this study has pilot and explorative character