scholarly journals Load distribution method in helicopter blade multibody dynamics system

2021 ◽  
Vol 258 ◽  
pp. 09076
Author(s):  
Anton Didenko ◽  
Vladislav Borisenko ◽  
Jose Leoro
Keyword(s):  
Coordinate System ◽  
Multibody Dynamics ◽  
Cross Sections ◽  
Aerodynamic Force ◽  
Cross Sectional ◽  
Distribution Method ◽  
Helicopter Blade ◽  
Average Value ◽  
Multibody Model ◽  
Blade Section

The paper focuses on the loads applied to the helicopter blade cross-sections in the multibody dynamics system. The main objective is to simplify the blade aerodynamics calculation and avoid time-consuming CFD methods. For this reason, the way of computing blade aerodynamics is proposed by using multibody dynamics methods with a linear-elastic blade model. As the primary tool for further research, the MCS Adams software package is selected. Splitting the main rotor blade into a finite number of sections, each having its own average value of installation and coning angles, simplifies the calculation. Afterward, expressions for the total flow velocity around the blade section and its angle of attack are obtained through vector operations. This provides a measure of aerodynamic forces acting on each section in its cross-sectional coordinate system. In conclusion, the article provides the formalized method of aerodynamic force distribution between blade sections in the multibody model as well as the correlation between the flow coordinate system and the blade chord coordinate system.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Automated 3D measurement of fiber cross section morphology in handsheets

2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Image Plane ◽  
3D Measurement ◽  
Cross Sectional ◽  
Fiber Cross Section ◽  
Fiber Wall ◽  
Sectional Shape ◽  
Cross Section Geometry

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.

ASSESSMENT OF DEMENTIA IN THE TYPE 2 DIABETES BY MOCA

2017 ◽  
pp. 35-44
Author(s):  
Dinh Toan Nguyen
Keyword(s):  
Diabetes Mellitus ◽  
Risk Factors ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
High Sensitivity ◽  
Cross Sectional ◽  
Average Value ◽  
Lifestyle Risk ◽  
Diabetes Mellitus Risk

Background: Studies show that diabetes mellitus is the greatest lifestyle risk factor for dementia. Appropriate management and treatment of type 2 diabetes mellitus could prevent the onset and progression of mild cognitive impairment to dementia. MoCA test is high sensitivity with mild dementia but it have not been used and studied widespread in Vietnam. Aim: 1. Using MoCA and MMSE to diagnose dementia in patients with type 2 diabetes mellitus. 2. Assessment of the relationship between dementia and the risk factors. Methods: cross-sectional description in 102 patients with type 2 diabetes mellitus. The Mini-Mental State Examination(MMSE) and the Montreal Cognitive Assessment (MoCA) were used to assess cognitive function. The diagnosis of dementia was made according to Diagnostic and Statistical Manual of Mental Disorders. Results: The average value for MoCA in the group of patients with dementia (15.35 ± 2.69) compared with non-dementia group (20.72 ± 4.53). The sensitivity and specificity of MoCA were 84.8% and 78.3% in identifying individuals with dementia, and MMSE were 78.5% and 82.6%, respectively. Using DSMIV criteria as gold standard we found MoCA and MMSE were more similar for dementia cases (AUC 0.871 and 0.890). The concordance between MoCA and MMSE was moderate (kappa = 0.485). When considering the risk factors, the education,the age, HbA1c, dyslipidemia, Cholesterol total related with dementia in the type 2 diabetes. Conclusion: MoCA scale is a good screening test of dementia in patients with type 2 diabetes mellitus.When compared with the MMSE scale, MoCA scale is more sensitive in detecting dementia. Key words: MoCA, dementia, type 2 diabetes mellitus, risk factors

METABOLIC SYNDROME IN DIALYSIS PATIENTS

2016 ◽  
pp. 7-11
Author(s):  
Vinh Phu Hoang ◽  
Tam Vo ◽  
Van Tien Le ◽  
Thi Hoai Huong Vo
Keyword(s):  
Blood Pressure ◽  
Metabolic Syndrome ◽  
Renal Failure ◽  
Chronic Renal Failure ◽  
Artificial Kidney ◽  
Dialysis Patients ◽  
Cross Sectional ◽  
Average Value ◽  
The Metabolic Syndrome ◽  
End Stage

Objective: To review disorders elements of the metabolic syndrome in patients with end-stage chronic renal failure on dialysis cycle. Materials and methods: A cross sectional descriptive study of 85 patients including end-stage chronic renal failure in dialysis cycle from 5/2015 - 9/2016 at the Department of Artificial Kidney, Hue Central Hospital. Results: The prevalence of metabolic syndrome in dialysis patients was 37.65%. The prevalence of abdominal obesity was 30.6%; The prevalence of hypertension was 72.9%, the average value systolic blood pressure and diastolic blood pressure were 142.24 ± 27.53, 80.35 ± 12.48 mmHg; The prevalence of hyperglycemia was 28%, the average value blood glucose was 4.9 ± 1.19 mmol/l; The prevalence of triglyceride increase was 34.1%, the average value triglyceride was 1.59 ± 0.84 mmol/l. The prevalence of HDL-C increase was 47.1%, the average value HDL-C was 1.24 ± 0.33 mmol/l. Conclusion: The prevalence of metabolic syndrome in dialysis patients is very high, in which hypertension and HDL disturbances are the highest. Key words: chronic renal failure, dialysis, metabolic syndrome

scholarly journals Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

2021 ◽  
Vol 13 (6) ◽  
pp. 3255
Author(s):  
Aizhao Zhou ◽  
Xianwen Huang ◽  
Wei Wang ◽  
Pengming Jiang ◽  
Xinwei Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Heat Resistance ◽  
Cross Sections ◽  
Three Dimensional ◽  
Thermal Response ◽  
Transfer Efficiency ◽  
Cross Sectional ◽  
Heat Transfer Efficiency ◽  
Oval Tube

For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

Effects of Nano-Nozzles Cross-Sectional Geometry on Fluid Flow: Molecular Dynamic Simulation

2017 ◽  
Vol 34 (5) ◽  
pp. 667-678 ◽  
Author(s):  
H. Nowruzi ◽  
H. Ghassemi
Keyword(s):  
Fluid Flow ◽  
Velocity Profile ◽  
Cross Sections ◽  
Md Simulation ◽  
Flow Behavior ◽  
Water Model ◽  
Physical Parameters ◽  
Cross Sectional ◽  
Behavior Characteristics ◽  
Fanning Friction Factor

AbstractNano-nozzles are an essential part of the nano electromechanical systems (NEMS). Cross-sectional geometry of nano-nozzles has a significant role on the fluid flow inside them. So, main purpose of the present study is related to the effects of different symmetrical cross-sections on the fluid flow behavior inside of nano-nozzles. To this accomplishment, five different cross-sectional geometries (equilateral triangle, square, regular hexagon, elliptical and circular) are investigated by using molecular dynamics (MD) simulation. In addition, TIP4P is used for atomistic water model. In order to evaluate the fluid flow behavior, non-dimensional physical parameters such as Fanning friction factor, velocity profile and density number are analyzed. Obtained results are shown that the flow behavior characteristics appreciably depend on the geometry of nano-nozzle's cross-section. Velocity profile and density number for five different cross sections of nano-nozzle at three various measurement gauges are presented and discussed.

Constraint-Based Reverse Engineering From Ultrasound Cross-Sections

1997 ◽  
Author(s):  
Jai Menon ◽  
Ranjit Desai ◽  
Jay Buckey
Keyword(s):  
Reverse Engineering ◽  
Cross Sections ◽  
Biomedical Applications ◽  
Engineering Application ◽  
Volume Data ◽  
Cross Sectional ◽  
Reverse Engineer ◽  
Network Bandwidth ◽  
Complex Topology

Abstract This paper extends the “cross-sectional” approach for reverse engineering, used abundantly in biomedical applications, to the mechanical domain. We propose a combination of “projective” and cross-sectional algorithms for handling physical artifacts with complex topology and geometry. In addition, the paper introduces the concept of constraint-based reverse engineering, where the constraint parameters could include one or more of the following: time, storage (memory, disk-space), network bandwidth, Quality of Service (output-resolution), and so forth. We describe a specific reverse-engineering application which uses ultrasound (tilt-echo) imaging to reverse engineer spatial enumeration (volume) representations from cross-sectional data. The constraint here is time, and we summarize how our implementation can satisfy real-time reconstruction for distribution of the volume data on the internet. We present results that show volume representations computed from static objects. Since the algorithms are tuned to satisfy time constraints, this method is extendable to reverse engineer temporally-varying (elastic) objects. The current reverse engineering processing time is constrained by the data-acquisition (tilt-echo imaging) process, and the entire reverse engineering pipeline has been optimized to compute incremental volume representations in the order of 3 seconds on a network of four processors.

A semi-automated measurement of muscle fiber size using the Imaris software

2021 ◽  
Author(s):  
Jennifer E. Gilda ◽  
Joon-Hyuk Ko ◽  
Aviv-Yvonne Elfassy ◽  
Nadav Tropp ◽  
Anna Parnis ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Statistical Tests ◽  
Muscle Fibers ◽  
Fluorescent Labeling ◽  
Cross Sectional ◽  
Short Period ◽  
Fiber Size ◽  
Specific Protease

The size and shape of skeletal muscle fibers are affected by various physiological and pathological conditions, such as muscle atrophy, hypertrophy, regeneration, and dystrophies. Hence, muscle fiber cross-sectional area (CSA) is an important determinant of muscle health and plasticity. We adapted the Imaris software to automatically segment muscle fibers based on fluorescent labeling of the plasma membrane, and measure muscle fiber CSA. Analysis of muscle cross sections by the Imaris semi-automated and manual approaches demonstrated a similar decrease in CSA of atrophying muscles from fasted mice compared with fed controls. In addition, we previously demonstrated that downregulation of the Ca2+-specific protease calpain-1 attenuates muscle atrophy. Accordingly, both the Imaris semi-automated and manual approaches showed a similar increase in CSA of fibers expressing calpain-1 shRNA compared with adjacent non-transfected fibers in the same muscle cross section. Although both approaches seem valid for measurements of muscle fiber size, the manual marking method is less preferable because it is highly time-consuming, subjective, and limits the number of cells that can be analyzed. The Imaris semi-automated approach is user-friendly, requires little training or optimization, and can be used to efficiently and accurately mark thousands of fibers in a short period of time. As a novel addition to the commonly used statistics, we also describe statistical tests that quantify the strength of an effect on fiber size, enabling detection of significant differences between skewed distributions that would otherwise not be detected using typical methods.

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