scholarly journals The influence of friction on gas parameters in the minimum section of nozzles

2021 ◽  
Vol 2057 (1) ◽  
pp. 012069
Author(s):  
V S Okhotin ◽  
E V Dzhuraeva
Keyword(s):  
Cross Section ◽  
Gas Flow ◽  
Critical Pressure ◽  
Frictional Heating ◽  
Frictional Heat ◽  
Outlet Section ◽  
Flow Process ◽  
Cross Sectional ◽  
Convergent Nozzle ◽  
Minimum Cross Section

Abstract Processes of gas flow in nozzles, accompanied by the release of frictional heat, are presented in the form of polytropic processes. The polytropic process index n determines the degree of irreversibility of the gas flow process caused by the release of frictional heating. Relations are obtained to calculate the flow rate and thermodynamic properties of gas in the minimum section of the Laval nozzle and in the outlet section of the convergent nozzle at a pressure behind the nozzle less than the critical pressure. The gas calculated parameters (pressure, temperature, specific volume, velocity, cross-sectional area) in the minimum cross-section differ from the recommended values in the reference literature [1]. In particular, the gas pressure in the minimum cross section turns out to be higher than the critical pressure recommended in [1].

Growth of Gallium Nitride Nanowires and Nanospirals

2006 ◽  
Vol 963 ◽  
Author(s):  
Goutam Koley ◽  
Zhihua Cai
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Gas Flow ◽  
Circular Cross Section ◽  
Catalyst Layer ◽  
Cross Sectional ◽  
Growth System ◽  
Set Up ◽  
Irregular Growth ◽  
Quartz Tube Furnace

ABSTRACTGaN nanostructure synthesis was done in a quartz tube furnace using ammonia and liquid Ga as precursors, and hydrogen as the carrier gas. Ni nanoparticles formed due to annealing, has been used as the catalyst layer, facilitating vapor-liquid-solid growth of the nanostructures. The growth process resulted in the formation of two types of structures, straight nanowires, and irregular growth sometimes resulting in nanospirals. Growth using uniform distribution of catalyst over the entire surface resulted in growth of straight nanowires, while growth performed on catalyst patterned surface resulted in growth of nanospirals. The diameter of the nanowires varied from 20 – 100 nm, while for spirals the cross-sectional diameters were found to be in the range of 100 nm – 1 micron, and spiral diameters in the range of several microns. Using the present growth system and gas flow set-up, it was possible to synthesize ultra-long nanowires and spirals, with overall lengths exceeding 70 microns. The regular straight nanowires were found to have a smooth circular cross-section, while the irregular wires and nanospirals were found to have a very rough surface with approximate hexagonal or triangular cross-sections. Some of the spirals changed into straight nanowires with uniform triangular cross-sections. While more investigations are required to fully establish their structures, based on preliminary characterization and past studies, we conclude that the nanowires with circular cross-sections grow along the c-direction [0001], while the spirals and consequent triangular cross-section nanowires grow along one of the non-polar directions. The formation of spirals themselves may be related to the polarization properties of GaN, similar to those predicted for ZnO nanosprings and nanoribbons.

scholarly journals CROSS SECTION OF ELECTRON ANTINEUTRINO INTERACTION WITH 40AR AND 84KR AND ITS RELEVANCE TO GEONEUTRINO DETECTION

2021 ◽  
Vol 13 (1) ◽  
pp. 25-30
Author(s):  
Akmal Ferdiyan ◽  
Urip Nurwijayanto Prabowo
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Neutrino Interaction ◽  
Flow Process ◽  
Detection Mechanism ◽  
Cross Sectional ◽  
Electron Antineutrino ◽  
The Earth ◽  
Scintillator Material ◽  
The Cross

Neutrino can carry information from places that cannot be reached by the usual detection mechanism because it has a very weak interaction with matter. This can be utilized to study the heat flow process inside the earth by using information carried by geoneutrino (electron antineutrino). In this sense, it is important to know the characteristics of neutrino interaction with materials. In this study, the cross-section calculation of the electron antineutrino interaction with Ar-40 and Kr-84 was carried out using computational methods with the help of GENIE software. In the energy range of 0-10 MeV, the dominant interaction between the two materials is the interaction of QES NC and MEC types with an energy threshold of 5,09 MeV. Both Ar-40 and Kr-84 cannot be used as a scintillator material for geoneutrino detection because in the energy range 0-4,4 MeV the cross-sectional value of the CC interaction  is 0.

scholarly journals One-Dimensional Numerical Analysis of Cross-Sectional Area Variation Effects on Flow through the Gas Turbine Diffuser

2019 ◽  
Author(s):  
Nima Zamani Meymian ◽  
Reza Khodadadi
Keyword(s):  
Mach Number ◽  
Boundary Conditions ◽  
Gas Turbine ◽  
Cross Section ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Time Step ◽  
Cross Sectional ◽  
One Dimensional ◽  
Length Changes

In the paper, a one-dimensional compressible flow of gas inside the gas turbine’s diffuser has been simulated. The modeling has been performed to the aim of obtaining boundary conditions of outlet gas from diffuser and inlet gas to the combustion chamber. Depending on working flow regimes of fluid including subsonic, transonic, and supersonic flows, changes of diffuser cross-section have different effects on gas flow characteristics. For these effects to be correctly imposed, Mach number of the gas flow in each time-step affected by changes of cross-section would be determined, depending on the local Mach number in the same time-step. Obtaining distribution of Mach number along diffuser length, changes in other main characteristics of flow such as pressure, temperature, speed, and density for all of the points along diffuser length would be obtained. In order to verify the validity of the numerical algorithm used, the gas flow would be solved in a divergent nozzle and compared to other numerical methods. In the end, using gas turbine diffuser’s geometrical information, compressible gas flow inside it would be studied using the actual boundary conditions for a 25 MW gas turbine.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

Profil Penyakit Malaria Di Rumah Sakit Islam Siti Rahmah Padang Tahun 2018

2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana ◽  
Salmi Salmi
Keyword(s):  
Observational Study ◽  
Frequency Distribution ◽  
Cross Section ◽  
Laboratory Tests ◽  
Age Group ◽  
Normal Range ◽  
Cross Sectional ◽  
West Sumatra ◽  
Severity Of The Disease

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.

Profil Penyakit Malaria di Rumah Sakit Islam Siti Rahmah Padang Tahun 2018

2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana Y ◽  
Salmi Salmi
Keyword(s):  
Observational Study ◽  
Frequency Distribution ◽  
Cross Section ◽  
Laboratory Tests ◽  
Age Group ◽  
Normal Range ◽  
Cross Sectional ◽  
West Sumatra ◽  
Severity Of The Disease

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.

Access of Key Population to Available HIV and TB Services in Nepal: A Cross Section Study

2019 ◽  
Vol 17 (1) ◽  
pp. 17-23
Author(s):  
B.B. Subba ◽  
N. Rimal ◽  
B.M. Shrestha
Keyword(s):  
Viral Load ◽  
Cross Section ◽  
General Knowledge ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Key Population ◽  
Mdr Tb ◽  
Study Population ◽  
Control And Management ◽  
Structured Questionnaire

Introduction: TB is considered one of the opportunistic infection among PLHIV. The increasing burden of HIV/TB co-infection among key population cause problem to maintain adherence to ART and DOTS services. The emergence of MDR-TB is one of the greatest challenge to control and management of both diseases. However, having knowledge and information of both diseases are important role to access the available HIV/TB services. Methods: A cross-sectional survey was conducted among key population who had HIV/TB co-infection in two-epidemic zone of Nepal. A pretested semi-structured questionnaire was used to collect data. ANOVA test was done to analyze the collected data by using SPSS version 20.0. Results: A total of 343 HIV/TB co-infected individuals were enrolled to the study. Most of participants were from ART and DOTS clients. Therefore, the study found that there was significance difference found between knowledge about TB (F=4.400, p= 0.005), causative agent of TB (F=3.160, p=0.025), risk of TB illness among PLHIV (F=8.491, p=0.001) and among key affected population. Moreover, there was significance difference found between access to OI treatment (F=5.113, p=0.002) and access to viral load (F=4.642, p=0.003) among key study population. In gender perspective, there was no significance difference to use and access to available HIV/TB services. Conclusion: The general knowledge on HIV/TB co-infection was significant association with key population. The knowledge on HIV/TB and access to NGOs’ help can significant effect to access the available HIV and TB services.

Automated Diagonal Slice and View Solution for 3D Device Structure Analysis

2018 ◽  
Author(s):  
Sang Hoon Lee ◽  
Jeff Blackwood ◽  
Stacey Stone ◽  
Michael Schmidt ◽  
Mark Williamson ◽  
...  
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Image Data ◽  
Planar Surface ◽  
Device Structure ◽  
Cross Sectional ◽  
Device Structures ◽  
The Cross ◽  
Planar Analysis

Abstract The cross-sectional and planar analysis of current generation 3D device structures can be analyzed using a single Focused Ion Beam (FIB) mill. This is achieved using a diagonal milling technique that exposes a multilayer planar surface as well as the cross-section. this provides image data allowing for an efficient method to monitor the fabrication process and find device design errors. This process saves tremendous sample-to-data time, decreasing it from days to hours while still providing precise defect and structure data.

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