PocketECG: A new continuous and real-time ambulatory arrhythmia diagnostic method

This article presents a new approach to ambulatory arrhythmia monitoring, one which can be viewed as a natural evolution of the existing non-invasive methods for diagnosing heart rhythm abnormalities. This new method combines the real-time capabilities of modern mobile cardiovascular telemetry systems with a quantitative way of reporting measured findings and continuous storage of the ECG data typical of Holter monitoring systems. It further combines this with a symptom-reporting capability typical of event monitoring applications. Combining all these features produces a single device which could be described as the ultimate arrhythmia diagnostic tool. (Cardiol J 2011; 18, 4: 454–460

The Stochastic Nature of the Fire Evacuation of People from Buildings

Aim: The purpose of this article is to present the stochastic nature of the process of evacuating people from buildings. This process depends on the behaviour of the group of evacuees, as well as the speed of their movement.Introduction: The article enumerates the elements involved in the estimated safe evacuation time, such as detection time, notification, the initial reactions of the people inside the building, and movement time. The most common reactions to fire alarms such as: trying to finishing the already started activities, packing and collecting personal belongings, looking for missing family members, attempts to extinguish the fire, trying to investigate the situation, theft attempts, etc., have been shown. These extends the evacuation time and results in lower safety levels for the evacuees. What is more, the article features human movement speed data which has been obtained from academic sources and which takes into consideration such circumstances as human traffic congestion on the escape routes, the types of movement, the specific conditions in the building, the type of place from which people are evacuating, the individual characteristics of the evacuees (such as gender, body weight and fitness levels) and finally the features of the escape route. An experiment has been carried out that not only showed the changing nature of human behaviour during evacuation but also proved the changeability of evacuation speeds of the same people in similar circumstances.Conclusions: A review of the available academic sources has been used to estimate the total evacuation time and analyse the progress of evacuation, which in turn has revealed that it is not only human behaviour that matters during evacuation but also the existence of the fire alarm systems in the building. as well as the speed of evacuation of every individual. It has been proven that the process is stochastic in nature, i.e. random, and depends on many variables.Practical significance: the experiment that has been carried out with the help from the firefighters from the local unit in Pabianice has confirmed that even the same person, in similar circumstances, can move at very different speeds, which means that it is impossible to perform exactly the same evacuation operation twice. The experiment was compared with a computer simulation made in the Pathfinder program, one of the most popular tools for fire safety engineering

Zastosowanie modyfikacji modelu Greenberga do szacowania czasu ewakuacji ludzi z budynków użyteczności publicznej

Objective: The article presents a proposition of a model for estimating people’s evacuation time from public utility buildings of category ZL III (not containing rooms designed for the simultaneous presence of more than 50 people who are not their regular users, not primarily intended for use by people with limited mobility). The model is based on the analogy between the theory of road traffic and the process of people’s movement during evacuation. Design and methods: In order to develop the model, a series of trial evacuations of people from public utility category ZL III buildings of varied geometry and number of users was conducted. A comparative analysis was performed concerning the evacuation times calculated with the use of models available in literature – a critical model of evacuation time, models designed by Togawa, Melenik and Booth, Galbreath, Pauls, methodology of the British Standard, and those derived from computer simulations performed with the use of the Pathfinder software. Based on the analysis of the conducted research and model considerations, an equation for the estimation of evacuation time was proposed based on a modified Greenberg’s equation derived from the road traffic theory. In the model modification, the concept of replacement length of evacuation route elements was applied, significantly slowing down people’s movement velocity, and a method for calculating them was proposed. Results: The evacuation times obtained in experimental research were compared to the model time values calculated from the models published in literature. A considerable dispersion of the achieved results was shown, ranging from –65.0% to +425.8% with respect to the evacuation times obtained experimentally. The performance of computer simulations brought evacuation times with a bias ranging from –54.4% to +26.0% with respect to the experiments conducted. Evacuation times calculated with the use of the proposed equation were in line with the experimental results with an error ranging from –12.3% to +13.8%. However, in comparison to the times obtained from additional computer simulations, representing the description of evacuation from buildings with highly varied geometry and various numbers of evacuees, the deviation of the calculated evacuation time from the proposed model was from –16.7% to +23.1%. In the vast majority of cases, the deviation of the result oscillated around ± 15% for a wide range of buildings’ geometry and the number of evacuees. Conclusions: The proposed model makes it possible to determine with sufficient accuracy the evacuation time of people from public utility buildings of category ZL III and can serve as a reliable source of comparative information.Cel: Artykuł przedstawia propozycję modelu szacowania czasu ewakuacji ludzi z budynków użyteczności publicznej ZL III (niezawierających pomieszczeń zaprojektowanych do jednoczesnego przebywania ponad 50 osób niebędących ich stałymi użytkownikami oraz nieprzeznaczonych w szczególności do użytku przez ludzi o ograniczonej zdolności poruszania się). Zaproponowany model bazuje na analogii między teorią ruchu drogowego a procesem przemieszczania się ludzi w trakcie ewakuacji. Projekt i metody: Przeprowadzono szereg próbnych ewakuacji ludzi z budynków użyteczności publicznej ZL III o różnej geometrii i liczbie użytkowników. Dokonano analizy porównawczej czasów ewakuacji obliczonych za pomocą dostępnych w literaturze modeli – modelu krytycznego czasu ewakuacji, Togawy, Melenika i Bootha, Galbreatha, Paulsa, metodyki British Standard oraz otrzymanych z symulacji komputerowych wykonanych za pomocą programu Pathfinder. Na podstawie analizy wykonanych badań oraz przeprowadzonych rozważań modelowych zaproponowano równanie szacowania czasu ewakuacji oparte na modyfikacji równania Greenberga wynikającego z teorii ruchu drogowego. W modyfikacji modelu zastosowano koncepcję długości zastępczej elementów dróg ewakuacyjnych znacząco spowalniających prędkość poruszania się ludzi i zaproponowano metodę ich obliczania. Wyniki: Porównano uzyskane w badaniach eksperymentalnych czasy ewakuacji z modelowymi wartościami czasów obliczonymi z opublikowanych w literaturze modeli. Wykazano, duży rozrzut otrzymanych wyników wynoszący od –65,0% aż do +425,8% w stosunku do uzyskanych eksperymentalnie czasów ewakuacji. Wykonując symulację komputerową, uzyskano czasy ewakuacji obarczone błędem od –54,4% do +26,0% w stosunku do przeprowadzonych eksperymentów. Obliczone czasy ewakuacji za pomocą zaproponowanego równania zgadzały się z wynikami eksperymentalnymi z błędem od –12,3% do +13,8%. Natomiast w porównaniu z czasami uzyskanymi z dodatkowych symulacji komputerowych, reprezentujących opis ewakuacji z budynków o bardzo różnej geometrii i różnej liczbie ewakuujących się ludzi, odchylenie wyniku obliczanego czasu ewakuacji z zaproponowanego modelu wyniosło od –16,7% do +23,1%. W zdecydowanej większości przypadków odchylenie wyniku oscylowało w granicach około ±15% dla szerokiej gamy geometrii budynków oraz różnej liczby ewakuujących się osób. Conclusions: Zaproponowany model pozwala na wyznaczenie z zadowalającą dokładnością czasu ewakuacji ludzi z budynków użyteczności publicznej ZL III i może stanowić wiarygodne źródło informacji porównawczych

A comparison between model-based evacuation times and experimental data

Purpose: The aim of this article was to compare the evacuation times obtained from public buildings, using selected mathematical models, with times of evacuations carried out experimentally.Introduction: In the article, various mathematical models are presented in order to prove their use in fire evacuation time estimates. These include the critical evacuation time model, the Togava model, the Melenik and Booth model, the Galbreath model and the Pauls model. In order to compare the accuracy of the fire evacuation time estimates obtained by means of the above-mentioned methods, which are meticulously described in professional sources, a variety of real-life evacuations have been analysed, including evacuations from the Institute of Industrial Chemistry in Warsaw, the Public Television building in Lodz, the Marshal’s Office in Lodz, and the Local Fire Rescue Unit in Pabianice. The time checks obtained experimentally during the abovementioned fire drills have been set against the estimates obtained through mathematical analysis and the Pathfinder software computer simulation.Conclusions: professional literature on the subject-matter provides various mathematical formulas which can be put into use to quickly estimate the movement time of evacuees. However, the simplicity of the formulas and, therefore, the simplicity of both the analysis and results, can often lead to calculation errors, especially when compared with real-life time checks. The discrepancy between the model-based time estimates and the estimates obtained through real-life experimentation can be rooted in the ignorance displayed by mathematicians as to the necessity of incorporating several critical parameters into their models, such as the structure of vertical/horizontal escape routes and the volume of human traffic within them. Different escape routes and traffic levels may result in highly varied movement speeds and can deeply affect the evacuation time estimates. The mathematical models are, for the most part, oblivious of such detailed aspects of evacuation and only take into consideration the general assessments which can be found in professional printed sources.Practical significance: Evacuation experiments which have been carried out in real life have given us the chance to juxtapose the time checks obtained through mathematical simulation with the factual data, which in turn enabled the critical review of the reliability of the models. What is more, the time estimates have been re-processed with the use of Pathfinder software. In conclusion, the comparative analysis has proven that the Pathfinder software, which incorporates the variable-control mathematical model, provides the most accurate and true to life evacuation time estimate

Analysis of the impact of pump system control on pressure gradients during emergency leaks in pipelines

The impact of a pump control system on the recorded pressure values along the pipeline during emergency leaks is discussed in the paper. A comparison was made for the designed experimental installation with a length of 1100 m and a diameter of DN 63 mm. The calculations were made using the Epanet 2 program. Results of the performed calculations prove that apart from a detailed description of hydraulic parameters of the pipeline on the size of emergency leaks from the pipeline, it is also important to properly describe the pump control system

Analysis of the impact of pump system control on pressure gradients during emergency leaks in pipelines

The impact of a pump control system on the recorded pressure values along the pipeline during emergency leaks is discussed in the paper. A comparison was made for the designed experimental installation with a length of 1100 m and a diameter of DN 63 mm. The calculations were made using the Epanet 2 program. Results of the performed calculations prove that apart from a detailed description of hydraulic parameters of the pipeline on the size of emergency leaks from the pipeline, it is also important to properly describe the pump control system

Effect of Deflocculant Addition on Energy Savings in Hydrotransport in the Lime Production Process

The subject of the research was limestone hydromixture consisting of particles of a mean size of 45.5 μm conveyed by water in a pipeline of a total length of 632 m. In the paper, the results of rheological measurements of tested hydromixtures after the application of deflocculant consisting of waste product from the lime production process in the form of mineral particles and commonly known dispersant were presented. Calculations of pressure drop including hydromixtures with volume concentrations in the range of 21.30–50.00%, and density ranging from 1140–1410 kg/m3 in a pipeline of 200 mm diameter are presented. A decrease in friction losses in the flow in the pipeline of hydromixtures with different mass concentrations after the addition of deflocculant was observed. The study revealed that the addition of deflocculant resulted in a reduction of friction in the pipeline, enabling the pumping of hydromixtures with twice higher solids concentrations than originated from industrial installation, with a lower volumetric flow rate. This resulted in a decrease of the power consumption of the motor driving the pump, and obtained significant energy savings in the hydromixture transport process. The maximum energy saving achieved was equal to 58%

Effect of Deflocculant Addition on Energy Savings in Hydrotransport in the Lime Production Process

The subject of the research was limestone hydromixture consisting of particles of a mean size of 45.5 μm conveyed by water in a pipeline of a total length of 632 m. In the paper, the results of rheological measurements of tested hydromixtures after the application of deflocculant consisting of waste product from the lime production process in the form of mineral particles and commonly known dispersant were presented. Calculations of pressure drop including hydromixtures with volume concentrations in the range of 21.30–50.00%, and density ranging from 1140–1410 kg/m3 in a pipeline of 200 mm diameter are presented. A decrease in friction losses in the flow in the pipeline of hydromixtures with different mass concentrations after the addition of deflocculant was observed. The study revealed that the addition of deflocculant resulted in a reduction of friction in the pipeline, enabling the pumping of hydromixtures with twice higher solids concentrations than originated from industrial installation, with a lower volumetric flow rate. This resulted in a decrease of the power consumption of the motor driving the pump, and obtained significant energy savings in the hydromixture transport process. The maximum energy saving achieved was equal to 58%

The simple calibration procedure on the example of small town water supply system

The practical application of the model of water supply network realized in the program Epanet 2 requires the calibration of the model. The proposed simple calibration procedure, allows for taking into account the changes in resistance caused by the aging process, to be substituted by resistance coefficient K. In order to determine the substitute resistance coefficient K, the fire hydrant flow tests could be used, which allows to determine the aging for a given material. Calibration of the water supply network model is shown on the example of a small urban network in central Poland.

Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization.

The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G' and G" and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process