Identification of a model of crank shaft with a damper of torsional vibrations

The paper presents modelling and the process of dynamic model identification of crankshaft system. At the beginning some information about design, operation and test of crankshaft systems is shown. The next section describes the process of crank-piston mechanism with a vibration damper modelling and the method of obtaining the motion equation. The last but one section demonstrates some aspects of the process of dynamic model identification. Moreover, tests and numerical simulation are presented. At the end, there is a summary of the whole paper. Conclusions about modelling and identification of dynamic model of crankshaft systems are shown

On the need of vibroacoustic axiomatics

The term ‘vibroacoustics’ is nowadays a commonly used notion of interdisciplinary scientific domain which links the elements of the vibration theory and theoretical acoustics with practical (engineering) methods of solving problems in the field of vibrations and noise minimization using increasingly developing measurement methods (observations). Unanswered remains the question whether the discipline defined in such a way constitutes a separate study and therefore needs implementation of its own axiomatics which orders the domain and facilitates teaching. This paper shows that the lack of uniform fundamental assumptions might easily lead to serious mistakes

Analysis of critical states of composite drive shafts with two reduced masses – selection of the right model

Carbon fiber drive shafts are nonlinear structures of complex character, difficult to establish “a’priori”. The only way of modeling is to make identification based on the results of measurements of real objects. In previous works, Authors describe the process of building a mathematical model of such a system and its identification on the basis of experimental results but for only one reduced mass. On this basis, however, it is not possible to write a two-mass model because the identified function describing the resilience characteristics also ‘covers’ errors of other model parameters. So, Authors in this paper showed the process of selection of right model which can show the effects of passing shaft’s critical speeds by system with two reduced masses. In conclusion, future model identification procedure for nonlinear phenomena was announced

Identification of a model of the crankshaft with a damper of torsional vibrations

The paper presents modelling and the process of dynamic model identification of the crankshaft system. At the beginning some information about design, operation and test of crankshaft systems is shown. The next section describes the process of the crank-piston mechanism with a vibration damper modelling and the method of obtaining the motion equation. The last but one section demonstrates some aspects of the process of dynamic model identification. Moreover, tests and numerical simulation are presented. At the end, there is a summary of the whole paper. Conclusions about modelling and identification of the dynamic model of crankshaft systems are shown

How does early decompressive craniectomy influence the intracranial volume relationship in traumatic brain injury (TBI) patients?

Background. Decompressive craniectomy (DC) is a common neurosurgical procedure involving the removal of part of the skull vault combined with subsequent duroplasty. The goal of DC is to produce extra space for the swollen brain and/or to reduce intracranial pressure. In the present study, DC was performed in order to create space for the swollen brain. Aim of the study: to compare the volume alteration of selected intracranial fluid spaces before and after DC, to evaluate the volume of post-decompressive brain displacement (PDBD) and the largest dimension of oval craniectomy (LDOC), and to assess the early clinical effects of DC. Material and methods. The study group consisted of 45 patients with traumatic brain injury (four females and 41 males, mean age 54.5 years) who underwent DC (not later than five hours after admission to hospital) due to subdural haematomas and/or haemorrhagic brain contusions localised supratentorially and diagnosed by computed tomography (CT). The mortality rate in the study group was 40%. Study calculations were performed using Praezis Plus software by Med Tatra, Zeppelin and Pax Station by Compart Medical Systems. For statistical analysis, IBM SPSS Statistics software was used. Results. The DC-related additional space was responsible for a statistically significant increase in the volume of preoperatively compressed intracranial fluid spaces. The mean volume of extra space filled by the swollen brain was 42.2 ml ± 40.7. The best early treatment results were achieved in patients under the age of 55. Conclusions. DC has limited effectiveness in patients aged over 70 years. In every patient with clamped basal cisterns, a skin incision enabling appropriate LDOC should be planned before surgery. DC should be as large as possible, and the limits of its dimensions should be the limits of anatomical safety

Polymerase chain reaction based detection of bacterial 16S rRNA gene in the cerebrospinal fluid in the diagnosis of bacterial central nervous system infection in the course of external cerebrospinal fluid drainage. Comparison with standard diagnostics currently used in clinical practice

Background and purpose External drainage of cerebrospinal fluid (CSF) is a commonly used neurosurgical procedure. Complications of the procedure comprise central nervous system (CNS) bacterial infections, the frequency of which is estimated at around 6–10%. Detection of these infections is ineffective in many cases. The aim of the study was to evaluate the usefulness of a polymerase chain reaction (PCR)-based detection of bacterial 16S rRNA gene (16S rDNA) in the CSF. Material and methods The study group consisted of 50 patients. Clinical signs of CNS infection were monitored and routine laboratory and microbiological tests were performed. The results of standard methods were compared with the bacterial 16S rDNA detection. Results Using cultures, CNS infection was diagnosed in 8 patients, colonization of the drainage catheter in 6 patients, and sample contamination in 7 patients. In the group of the remaining 29 patients, no positive CSF culture was obtained and 13 of these patients also had all negative results for 16S rDNA detection. For the remaining 16 patients of this group, CNS infection, colonization of the catheter and sample contamination were diagnosed via PCR alone. Routine biochemical CSF tests and blood inflammatory parameters had a supporting value. Conclusions Routine hospital tests do not provide rapid and efficient detection of the external drainage related bacterial CNS infection. It is justified to use several diagnostic methods simultaneously. The16S rDNA determination in CSF can increase the probability of detection of possible pathogens

UML Simulation of a TopologyConfiguration Model, Journal of Telecommunications and Information Technology, 2012, nr 4

The article presents the application of simulation methods for topological models to analyze and design information systems. By using UML extensions and the UAL language it is possible not only to build a topological model for software, but also to perform efficient simulations of topological models. Additionally, it is possible to take into account the restrictive conditions stored in UAL and OCL languages. To execute the simulation the authors used an simulator from IBM. These concepts and methods are illustrated by examples

The effect of TCDD dioxin on the rat liver in biochemical and histological assessment

Eighteen male Wistar rats were divided into 3 groups of 6 animals each. Two groups received different intraperitoneal doses of TCDD (0.75 and 8 μg) in DMSO solution and the third group (control) received only DMSO on days 0, 7 and 14. On day 21 the animals were sacrificed, and then blood tests, pathological examination and CYP1A1 activity measurement were performed. In rats that received a high dose of dioxin (8 μg) hepatic lobules revealed parenchymal degeneration and vacuolization of hepatocytes was observed, and also an increased CYP reaction was found in central parts of lobules, around the central vein. The reaction in control and low dose groups was weak. The resorufin level was significantly (P<0.05) higher in the group receiving a low dose of dioxin as compared to the control group. The study confirmed that TCDD damages the rat liver in a dose-dependent manner. Administration of high TCDD doses causing major liver damage also damaged CYP1A1 (based on higher resorufin levels in epiluminescence). TCDD activates CYP1A1, which was confirmed by increased immunohistochemical reactivity of central areas of hepatic lobules

The Polish Interventional Cardiology TAVI Survey (PICTS) : adoption and practice of transcatheter aortic valve implantation in Poland

Introduction: Few studies have assessed the development of transcatheter aortic valve implantation (TAVI) in Poland since its introduction in 2008, and data on current TAVI activity or practice are missing. Aim: To assess the dynamics of TAVI adoption in Poland and to detect differences among Polish centres in TAVI practice and decision-making. Material and methods: The Polish Interventional Cardiology TAVI Survey (PICTS) was approved by the Polish Association of Cardiovascular Interventions and presented to all 21 national TAVI centres. Between 2008 and 2015 the cumulative number of TAVI performed in Poland was 2189. The annual number of TAVI rose from 8 in 2008 to 670 in 2015 (0.21 to 17.4 implants per million inhabitants, respectively). Results: The median TAVI experience per centre was 80 procedures (95% CI: 38.1–154.6). In 2015 the TAVI penetration rate reached 5.12% of the estimated eligible Polish population. Inoperable and high-risk patients are treated with TAVI in all centres, with 52% of Heart Teams also qualifying medium-risk patients. The rate of transfemoral implantations increased to 83.2% of all procedures in 2015, while transapical implantations decreased to 12%. The frequency of subclavian, direct aortic or transcarotid routes in 2015 was below 3% each. Conclusions: The PICTS survey observed a positive but slow rate of adoption of TAVI in Poland. When compared to Western European countries, our findings highlight a significant treatment gap in high or prohibitive surgical risk patients with severe aortic stenosis. Remarkable variations in TAVI practices among Polish TAVI centres warrant publication of joint national guidelines and recommendations

Risk factors for bleeding complications in patients undergoing transcatheter aortic valve implantation (TAVI)

Background: The risk of bleedings in transcatheter aortic valve implantation (TAVI) patientsincreases due to age and concomitant diseases. The aim of the study was to assess the risk ofbleedings, their influence on early prognosis of TAVI patients and utility of the TIMI andGUSTO scales in the evaluation of bleeding and in prediction of blood transfusion.Methods: This was a single center study of in-hospital bleedings in 56 consecutive TAVIpatients. Bleedings were classified according to the GUSTO and TIMI scales. HASBLED‘sscale risk factors, diabetes mellitus, female sex, the route of bioprosthesis implantation and inhospitalantithrombotic treatment were analyzed. Statistical analysis consisted of c2, Fisher’sexact, Wilcoxon tests and logistic regression analysis.Results: Serious bleedings occurred in 35 (62.5%) patients. There was no significantcorrelation with HASBLED score. History of anemia was a significant predictor of bleeding inGUSTO (p = 0.0013) and TIMI (p = 0.048) scales. No bleedings in patients receivingvitamin K antagonists (VKA) pre- and VKA plus clopidogrel post intervention were observed.Patients with bleedings according to the GUSTO scale more often required blood tranfusionthan in TIMI scale (p = 0.03).Conclusions: History of anemia is the strongest predictor of serious bleedings. VKA beforeand VKA with clopidogrel after TAVI are safer than dual antiplatelet or triple therapy. TheTIMI and GUSTO scales can adequately classify bleeding after TAVI, however the GUSTObetter predicts transfusions