scholarly journals Method of Constructing an Asymmetric Human Bronchial Tree in Normal and Pathological Cases

2020 ◽  
Vol 15 (2) ◽  
pp. 148-157
Author(s):  
v. Medvedev
Keyword(s):  
Airway Obstruction ◽  
Bronchial Tree ◽  
Pulmonary Diseases ◽  
Cylindrical Shape ◽  
Analytical Design ◽  
Geometric Characteristics ◽  
Analytical Formulas ◽  
Two Parameters ◽  
Pathological Case ◽  
Order Smoothness

The goal of the study is the analytical design of the full asymmetric human bronchial tree (irregular dichotomy) for healthy patients and patients with obstructive pulmonary diseases. For this purpose, the author has derived the special analytical formulas. All surfaces of the bronchial tree are matched with the second-order smoothness (there are no acute angles or ribs). The geometric characteristics of the human bronchial tree in the pathological case are modeled by a “starry” shape of the inner structure of the bronchus; a level of the pathology is defined by two parameters: bronchus constriction level and level of distortion of the cylindrical shape of the bronchus. Closed analytical formulas allow a researcher to construct the human bronchial tree of an arbitrary complexity (up to alveoli); moreover, the parametric dependences make it possible to specify any desirable level of airway obstruction.

scholarly journals Analytical Design of the Human Bronchial Tree for Healthy Patients and Patients with Obstructive Pulmonary Diseases

2019 ◽  
Vol 14 (2) ◽  
pp. 635-648 ◽  
Author(s):  
A.E. Medvedev ◽  
P.S. Gafurova
Keyword(s):  
Airway Obstruction ◽  
Bronchial Tree ◽  
Pulmonary Diseases ◽  
Cylindrical Shape ◽  
Analytical Design ◽  
Geometric Characteristics ◽  
Analytical Formulas ◽  
Two Parameters ◽  
Pathological Case ◽  
Order Smoothness

The study is aimed at the analytical design of the full human bronchial tree for healthy patients and patients with obstructive pulmonary diseases. Analytical formulas for design of the full bronchial tree are derived. All surfaces of the bronchial tree are matched with the second-order smoothness (there are no acute angles or ribs). The geometric characteristics of the human bronchial tree in the pathological case are modeled by a “starry” shape of the inner structure of the bronchus; the pathology degree is defined by two parameters: bronchus constriction level and degree of distortion of the cylindrical shape of the bronchus. Closed analytical formulas allow the human bronchial tree of an arbitrary complexity (up to alveoli) to be designed; moreover, the parametric dependences make it possible to specify any desirable degree of airway obstruction.

scholarly journals Analytical method of calculation of thermal fields of cast parts during crystallization

2021 ◽  
Vol 1,2021 (1,2021(126)) ◽  
pp. 5-13
Author(s):  
Liutyi Rostislav
Keyword(s):  
Mathematical Method ◽  
Thermal Field ◽  
Complex Method ◽  
Cylindrical Shape ◽  
Mathematical Basis ◽  
Method Of Calculation ◽  
Thermal Fields ◽  
Analytical Formulas ◽  
Molding Materials ◽  
Cast Parts

The aim of the work is to create a mathematical method that allows to calculate the distribution of thermal fields in cast parts during crystallization using a system of analytical formulas. During the calculations, a combination of known analytical formulas GF was used. Balandin, AY Weinik, S. Schwartz with their own original mathematical solutions created on the basis of the analysis of thermophysical processes in castings in the process of their crystallization. Computer simulation of thermal fields using the LVMFlow program was used to compare the results. According to the created mathematical method, examples of calculation of thermal fields for two castings made of steel 25L of hollow cylindrical shape, the wall thickness of which is 100 mm and 4 mm, respectively, are given. Calculations were performed for the conditions of crystallization of castings in a single sand form. The comparison of results of calculations by the developed method and with use of the existing software is presented. For the first time, based on our own mathematical and thermophysical developments, a comprehensive calculation method for determining the thermal field of the casting during crystallization and cooling was developed. casting. The technique is expressed in a number of analytical formulas, each of which describes a specific thermal process that occurs in the casting. This takes into account the features of the casting configuration. The created complex method of calculation of thermal fields of cast parts is a mathematical basis for determining the thermal fields of molds and rods, which allows to predict their properties and select the optimal molding materials. The created technique can also be offered as a mathematical basis for refining applied computer programs for foundry production. CASTING, TEMPERATURE, THERMAL FIELD, COOLING DYNAMICS, COOLING DURATION, MATHEMATICAL LAW, COLORING FRONT, CALCULATION

scholarly journals Mathematical modeling of groundwaters pressure distribution in the underground structures by cylindrical form zone

2018 ◽  
Vol 196 ◽  
pp. 02025 ◽  
Author(s):  
Valeriy Telichenko ◽  
Vladimir Rimshin ◽  
Vladimir Eremeev ◽  
Vladimir Kurbatov
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Pressure Distribution ◽  
Underground Structure ◽  
Viscosity Coefficient ◽  
Soil Porosity ◽  
Cylindrical Shape ◽  
Underground Structures ◽  
Cylindrical Form ◽  
Analytical Formulas

A mathematical model is developed for studying the distribution of groundwater pressure and its variation in the zone of underground structures of a cylindrical shape. Based on the created model, the influence of the thickness of the aquifer, the soil porosity, the filtration coefficient, the viscosity coefficient and the piezoelectric conductivity coefficient on the pressure that groundwater exerts on the lower part of the underground structure is investigated. The analysis of the possibility of pushing the structure and breaking the foundation under the influence of pressure caused by groundwater is analyzed. Analytical formulas are obtained for estimating the stresses in the foundation and predicting the possibility of its destruction.

scholarly journals POPULATION BOTTLENECKS AND NONEQUILIBRIUM MODELS IN POPULATION GENETICS. III. GENIC HOMOZYGOSITY IN POPULATIONS WHICH EXPERIENCE PERIODIC BOTTLENECKS

Genetics ◽  
1985 ◽  
Vol 111 (3) ◽  
pp. 691-703
Author(s):  
Takeo Maruyama ◽  
Paul A Fuerst
Keyword(s):  
Population Size ◽  
Cycle Length ◽  
Extreme Values ◽  
Gene Diversity ◽  
Population Bottlenecks ◽  
Specific Time ◽  
Large Gene ◽  
Analytical Formulas ◽  
Two Phases ◽  
Two Parameters

ABSTRACT The amount of variability in a population that experiences repeated restrictions in population size has been calculated. The restrictions in size occur cyclically with a fixed cycle length. Analytical formulas for describing the gene identity at any specific time in the expanded and restricted phases of the cycle, and for the average and second moment of the gene identity, have been derived. It is shown that the level of genetic diversity depends critically on the two parameters that account for the population size, mutation rate and the time of duration for each of the two phases in the cycle. If one or both of these composite parameters are small, the gene diversity will be much reduced, and population gene diversity will then be predictable from knowledge of the harmonic mean population size over the entire cycle. If these parameters take on intermediate values, diversity changes constantly during the cycle, fluctuating steadily from a high to a low value and back again. If these parameters are large, gene diversity will fluctuate rapidly between extreme values and will stay at the extremes for long periods of time.

scholarly journals Изменение температуры Кюри в пористом материале

2020 ◽  
Vol 46 (14) ◽  
pp. 6
Author(s):  
А.В. Шишулин ◽  
В.Б. Федосеев ◽  
А.В. Шишулина
Keyword(s):  
Curie Temperature ◽  
Cohesive Energy ◽  
Nanoporous Materials ◽  
Effective Diameter ◽  
Pore Shape ◽  
Magnetic Transitions ◽  
Shape Coefficient ◽  
Geometric Characteristics ◽  
Macroscopic Objects ◽  
Two Parameters

In this paper, the dependence of magnetic transitions temperatures of nanoporous materials on pore geometric characteristics (volume and shape) have been studied in the framework of the cohesive energy-based model in the case of pure nanoporous nickel and cobalt. Pore geometric characteristics have been taken into account using two parameters: its effective diameter and shape coefficient of a pore which characterizes the degree of deviation of its shape from the spherical one. The estimates allow expecting the possibility to obtain nanoporous macroscopic objects of ferromagnetic materials with a reduced Curie temperature which value also decreases with “complicating” the pore shape.

scholarly journals Analytical Study of Powder Stream Geometry in Laser-Based Direct Energy Deposition Process with a Continuous Coaxial Nozzle

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1306
Author(s):  
Qipeng Liu ◽  
Kun Yang ◽  
Yuehua Gao ◽  
Fencheng Liu ◽  
Chunping Huang ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Deposition Process ◽  
Sensitivity Analyses ◽  
Powder Flow ◽  
Forming Process ◽  
Direct Energy Deposition ◽  
Geometric Characteristics ◽  
Direct Energy ◽  
Analytical Formulas ◽  
Geometry Method

In the process of laser-based direct energy deposition, the particle concentration distribution and geometric characteristics of powder flow play an important role in laser–powder interaction and powder utilization, and they affect the forming quality and accuracy. In the current study, based on the geometry information of a powder nozzle and the divergence angles of a powder jet at the nozzle outlet, the geometric profile of a powder stream is analyzed. A set of formulas for calculating the geometric characteristics of the powder stream is derived based on an analytic geometry method. The influence of each parameter on the geometric characteristics of the powder stream is further studied using single-factor and sensitivity analyses. Validation is performed by comparing the results from the presented analytical expressions with those from experiments and/or simulations in published papers. The analytical formulas provided in this paper are simple and practical, providing a theoretical foundation for the control of powder flow and related processes in the forming process.

scholarly journals Use of beta blockers in patients with asthma and chronic obstructive pulmonary disease

2021 ◽  
Vol 74 (3-4) ◽  
pp. 127-133
Author(s):  
Andrej Preveden ◽  
Mirko Todic ◽  
Vanja Drljevic-Todic ◽  
Mihaela Preveden ◽  
Ranko Zdravkovic ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Cardiovascular Diseases ◽  
Airway Obstruction ◽  
Pulmonary Disease ◽  
Beta Blockers ◽  
Clinical Signs ◽  
Pulmonary Diseases ◽  
Chronic Obstructive ◽  
Bronchial Obstruction ◽  
Obstructive Pulmonary Disease

Introduction. Beta blockers play an essential role in the treatment of cardiovascular diseases, but also various other endocrinological, gastroenterological, ophthalmological and neurological disorders. The most important effects of beta blockers are a reduction in myocardial oxygen consumption and inhibition of renin secretion. Beta blockers are divided into three generations according to their selectivity - non-selective, cardioselective and vasodilating beta blockers. Beta blockers and obstructive pulmonary diseases. Patients with obstructive pulmonary diseases are significantly more likely to develop cardiovascular diseases compared to general population, largely due to common risk factors such as smoking, systemic inflammation, age, and genetic predisposition. The use of nonselective beta blockers carries a great risk for patients with obstructive pulmonary diseases, while cardioselective beta blockers can be used more extensively. Reversible airway obstruction is predominantly present in asthma, so that the adverse effects of beta blockers on the airways are significantly more pronounced in asthma compared to chronic obstructive pulmonary disease. Conclusion. In both asthma and chronic obstructive pulmonary disease, the use of highly cardioselective beta blockers such as bisoprolol and nebivolol is preferred. The use of beta blockers in patients with asthma requires great caution due to the possibility of bronchial obstruction, while in patients with chronic obstructive pulmonary disease they are somewhat safer. Patients must be closely monitored by a physician, with special attention focused on clinical signs of airway obstruction such as wheezing, shortness of breath, and prolonged expiration.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

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