192 research outputs found
Practical Fire Safety Assessment of Steel-beam Floors Made According to the Old Technologies – an Exemplary Case Study. Influence of the Initial Assumptions on the Final Results of Analyses
The purpose of this article is to present procedures and methodsfor assessing fire resistance of steel-beam floors with thejoists hidden within the thickness of the slab. These technologiesare currently experiencing their renaissance, both in contemporarilydesigned buildings and the existing ones, subjectedto comprehensive redevelopment, refurbishment or modernization.Due to their simplicity and ease of execution, these floorsare just perfect as technology ideal for repairs or alterations ofbuildings under use or in the case of need of complete replacementof existing floors with new ones. These arguments justifythe need to raise the subject of proper safety assessment of thesefloors in relation to the regulations and requirements of lawsapplicable in the EU and pursuant to provisions of the latestcodes for structural design. A significant part of the study consistsof a suggestive computational example, which is a sort ofguide, in which the author, by making detailed step-by-step calculationsproduces a finished pattern of procedure, intended formultiple use. The suggested method of procedure can be successfullyused in the assessment of the fire resistance of floorstructures with similar technical features. The computationalexample presented in the study shows that contrary to a popularbelief, the use of standard fire model does not always leadto conservative estimates. In the article summary, the authorformulates a number of practical applications and conclusions
Remarks on mathematical foundations of quantum mechanics
We show that the set-theoretic forcing is the essential part of the continuous measurement of a suitably rich Boolean algebra of quantum observables. The Boolean algebra structure of quantum observables enables us to
give a classical and geometric meaning to the results of measurements of the observables. The measurement takes place in the semiclassical state of the system which is the generic filter added by a forcing to the ZFC model based on the Borel measure algebra. The analogue of the semiclassical state (the pseudoclassical state) was described by Wesep in 2006 in his studies of the local hidden variables program in quantum mechanics
Generation of virtual anatomical models from the multimodal medical image data
In this work we present and discuss some methodological issues associated with the generation of the computer based anatomical models. The importance of the virtual patient models is becoming increasingly recognized in modern medicine. The advantages of using such biomedical virtual models are analogous to those of real system behavior simulation in the engineering or material sciences. Particularly significant is its role in the simulation of various pathogenic physiological processes and therapeutical procedures. Such models enable as well the optimization of many diagnostic and therapeutical subroutines. Segmentation, registration, measurement, interaction and visualization modules constitute actually the main pool of the software engineering tools, which enables the surgeon to create a virtual patient-specific anatomical model of the region of interest. Based on this model the physician can simulate and plan different treatment approaches as well as carry out quantitative measurements to identify the optimal therapeutical procedure
The structure of the real line in quantum mechanics and cosmology
We discuss the recently proposed model, where the spacetime in large scales is parametrized by the usual real line R, while at small (quantum mechanical) scales, the space is parametrized by the real numbers RM
from some formal model M of Zermelo–Fraenkel set theory. We argue that the set-theoretic forcing is an important ingredient of the shift from micro- to macroscale. The set RM, describing the space at the Planck era,
is merely a meager subset of R. It is Lebesgue non-measurable and all its measurable subsets have Lebesgue measure 0. According to this, the contributions to the cosmological constant from the zero-point energies of
quantum fields vanish. Moreover, the emerged irregularities in the real line can be considered as the source of the primordial quantum fluctuations
Computer based framework for cranio-maxillofacial surgery planning
Nowadays the process of surgical planning is a crucial point of every operation in the craniofacial region. In this work we focus on the planning of graft reconstructive surgery for autologous osseous grafts. The planning method consists of two stages. The non-automatic graft design step is followed by a fully automatic procedure to find the best harvesting site in the predefined donor region. The main idea of the proposed method is based on the registration paradigm. The optimal donor site is identified by performing an optimization of the surface based similarity measure between the donor region and the designed graft template. An efficient optimization method based on the Levenberg-Marquardt algorithm has been implemented
Epidemiology of mandibular fractures - frequency and trauma pattern comparison in seventies of twentieth century with modern times (2002-2012)
Introduction: Mandibular fractures are a group of most common trauma with which maxillofacial surgeons have to deal in their clinical practice.
Aim of the study: Analysis of mandibular fractures epidemiology in the group of patients treated in the Clinic of Maxillofacial Surgery at Poznan University of Medical Science between 2002 and 2012 and comparison of results with data from the period 1961-1974.
Material and methods: Material consisted of medical documentation of patients treated in the Clinic of Maxillofacial Surgery in Poznan due to mandibular fractures between 2002 and 2012. 1990 patients experienced mandibular trauma but only 1701 cases were described precisely enough to take part in the analysis. The population of patients were divided by sex and age (16th year of life was the border of the divide). Using this data, the amount of single and multi-fragmental fractures, percentage distribution of fractures among anatomical structures of the mandible, frequency of fractures in age groups and seasons of the year were calculated. Then, results were compared with a publication about the epidemiology of mandibular fractures between 1961-1974.
Results: The population of 1701 patients consisted of 1426 males, 235 females and 40 children up to 16 years old (25 boys and 15 girls). Male to female ratio was 6,13:1. Most fractures affected patients at an age between 20 and 30 years old, regardless of sex. On average, 199 hospitalization due to mandibular fractures a year had a place in a period of 2002-2012 (involving all cases). Most of the hospitalizations due to mandibular fractures occurred between April and September. From 2002 to 2012, 1864 anatomical structures were broken. Body (783), left angle (274), right condyle (241), left condyle (239) and right angle (195) were structures that were fractured most often. 895 (52,62%) cases were single fractures , 806 (47,38%) were multi-fragmental fractures. The greater the average amount of patients a year, the reduction of male to female ratio, single fractures to multi-fragmental fractures ratio is about 1:1, left angle in the group of most frequently fractured structures are the main differences between period 1961-1974 and 2002-2012.
Conclusion: Analysis indicates that the epidemiology of mandibular fractures is a complex problem. Some elements are constant but other changes dynamically across time. In the opinion of abroad scientists, the development of technology, motorization, and changes in human behavior are the main reasons for such evolution
Zasada działania i zastosowanie akcelerometrii w ocenie układu ruchu : przegląd narracyjny
Akcelerometria jest stosunkowo młodą, ale obiecującą metodą w dziedzinie badań nad chodem. Bazuje ona na zastosowaniu czujników mierzących przyspieszenie liniowe występujące w danym punkcie materialnym. Celem tego artykułu jest przegląd literatury pod
kątem zastosowania tej techniki w ocenie lokomocji człowieka, zalet i wad oraz rzetelności pomiaru. Przeglądnięto prace różnych autorów i porównano ich wyniki. Badania dotyczyły wykrywania faz chodu, obliczania parametrów takich jak prędkość czy długość kroków, oceny równowagi oraz monitorowania aktywności fizycznej. W celu sprawdzenia poprawności zarejestrowanych danych, porównywano je z odczytami systemu VICON, platform dynamometrycznych oraz specjalnych elektronicznych ścieżek. Analiza literatury
dostarczyła następujących wniosków. Zaletami akcelerometrii jest niski koszt urządzeń, ich niewielkie rozmiary oraz masa, a także
brak ograniczenia pomiaru do wnętrza laboratorium. Wady to przede wszystkim konieczność stosowania kabli, co utrudnia długotrwały monitoring aktywności fizycznej. Metoda jest rzetelna, o ile eksperyment jest prawidłowo zaplanowany i przeprowadzony. Najważniejsze warunki to właściwe umiejscowienie czujników, zapewniające dobre przyleganie do ciała mocowanie, jak najdokładniejsze
skoordynowanie osi anatomicznej z osią pomiaru oraz użycie właściwego algorytmu przetwarzania danych. Autorzy większości prac
uznają akcelerometrię jako wiarygodną i przydatną metodę do oceny parametrów chodu. Obecnie akcelerometry znajdują zastosowanie głównie przy badaniu wzorca chodu i oceny dysfunkcji, jako czujniki FES u pacjentów z opadającą stopą oraz podczas oceny równowagi oraz monitorowania aktywności fizycznej.Accelerometry is a relatively new but promising method of gait examination. It is based on the usage of sensors which measure linear
acceleration at a certain material point. The purpose of this article is to review the literature on the subject from the point of view of
applying this technique in assessing human gait, its advantages and shortcomings and the reliability of measurement. Papers by various
authors have been reviewed and their results compared. Research concerned detection of the phases and events of gait, calculation of
gait parameters such as speed and step length, balance evaluation and the monitoring of physical activity. In order to verify the correctness of the collected data, it was compared with the readings of the VICON system, force platforms and special electronic walkways.
An analysis of the literature resulted in the following conclusions: the advantages of accelerometry is the low cost of devices, their
small size and mass and measurement which is not limited to the laboratory. The disadvantage is first of all the necessity to use cables,
which makes it harder to conduct the long-term monitoring of physical activity. The method is reliable if the experiment is properly
planned and carried out. The most important conditions are the proper location of sensors, tight binding to the body, the most accurate
alignment of the anatomical axis with the measurement axis and the usage of a proper algorithm for data processing. The authors of the
majority of papers consider accelerometry to be a reliable and useful method of analyzing the parameters of gait. At present, accelerometers are used mainly for examining the model of gait and assessing dysfunctions, as sensors in FES assisted walking in patients
with dropped foot and during physical activity monitoring
The modification of the energy spectrum of charged particles by exotic open 4-smoothness via superstring theory
In this paper we present a model where the modified Landau-like levels of
charged particles in a magnetic field are determined due to the modified
smoothness of as underlying structure of the Minkowski
spacetime. Then the standard smoothness of is shifted to the
exotic , , . This is achieved by
superstring theory using gravitational backreaction induced from a strong,
almost constant magnetic field on standard . The exact string
background containing flat is replaced consistently by the
curved geometry of as part of the modified exact
backgrounds. This corresponds to the change of smoothness on
from the standard to some exotic . The
calculations of the spectra are using the CFT marginal deformations and
Wess-Zumino-Witten (WZW) models. The marginal deformations capture the effects
of the magnetic field as well as its gravitational backreactions. The spectra
depend on even level of WZW on SU(2). At the same time the WZ term as
element of determines also the exotic smooth
. As the consequence we obtain a non-zero mass-gap emerges
in the spectrum induced from the presence of an exotic .Comment: 11 pages, Revtex4-1, will appear IJGMMP Vol. 50(1), 201
The latent meaning of forcing in quantum mechanics
We analyze random forcing in QM from the dual perspective of the measure and category correspondence. The dual Cohen forcing allows interpreting the real numbers in a model M and its Cohen extension M[G] as
absolute subtrees of the binary tree (Cantor space). The trees are spanning non-trivial Casson handles of smooth exotic 4-manifolds, like R4. We formulate the consequences for the cosmological model with random forcing where dual smooth non-standard and non-flat Riemannian geometries have to appear
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