scholarly journals Fault Analysis for Reliability Centered Maintenance (RCM) in Machining

2021 ◽  
pp. 29-38
Author(s):  
Toshihiro Endo ◽  
Nobuyuki Hozumi
Keyword(s):  
Numerical Analysis ◽  
Research Performance ◽  
Leading Edge ◽  
Fault Analysis ◽  
The Other ◽  
Cross Sectional ◽  
Reliability Centered Maintenance ◽  
Blade Edge ◽  
Cross Sectional Profile ◽  
Sectional Profile

This contribution presents a numerical analysis based on the effects of aerodynamics of the bump-based humpback whale fins available on the turbine blade edge. In this research, performance comparisons have been made based on dual sequestered blades. One of the blades was sinusoidal in shaped with Bumped Lead Edge (BLE) and the other one with Upright Leading Edge (ULE). However, all the blades are based on a similar cross-sectional profile i.e. NACA-012. This research has been based on simulations of Reynold’s number i.e. 1.8.105 of Attack Angle (AA) i.e. from ‘0º - 30º’. At this angle, especially greater than 10º, the BLE has indicated an enhancement in about 3.5% to 9.0% lift and a reducing drag whereas the negligible variation in lifts and minor drag is displayed for AA less than 10º. The findings in this result for BLE have indicated a substantial achievement in aerodynamic features for particular AA.

scholarly journals Hydromechanics, Aerodynamics and Thermodynamics: Critical Numerical Analysis of Aerodynamics of BLE Turbine Blade

2021 ◽  
pp. 20-28
Author(s):  
Shih-Chau Lin
Keyword(s):  
Numerical Analysis ◽  
Turbine Blade ◽  
Research Performance ◽  
Leading Edge ◽  
Humpback Whale ◽  
The Other ◽  
Cross Sectional ◽  
Blade Edge ◽  
Cross Sectional Profile ◽  
Sectional Profile

This contribution presents a numerical analysis based on the effects of aerodynamics of the bump-based humpback whale fins available on the turbine blade edge. In this research, performance comparisons have been made based on dual sequestered blades. One of the blades was sinusoidal in shaped with Bumped Lead Edge (BLE) and the other one with Upright Leading Edge (ULE). However, all the blades are based on a similar cross-sectional profile i.e. NACA-012. This research has been based on simulations of Reynold’s number i.e. 1.8.105 of Attack Angle (AA) i.e. from ‘0º - 30º’. At this angle, especially greater than 10º, the BLE has indicated an enhancement in about 3.5% to 9.0% lift and a reducing drag whereas the negligible variation in lifts and minor drag is displayed for AA less than 10º. The findings in this result for BLE have indicated a substantial achievement in aerodynamic features for particular AA.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

scholarly journals Bonding widths of Deposited Polymer Strands in Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 871
Author(s):  
Cheng Luo ◽  
Manjarik Mrinal ◽  
Xiang Wang ◽  
Ye Hong
Keyword(s):  
Polymer Melt ◽  
Acrylonitrile Butadiene Styrene ◽  
High Viscosity ◽  
Numerical Results ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Nozzle Height ◽  
Special Cases ◽  
Cross Sectional Profile ◽  
Sectional Profile

In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

Measurement of cross-sectional profile for sub-15nm hp LS patterns in nanoimprint templates using small-angle x-ray scattering

2020 ◽  
Author(s):  
Kazuki Hagihara ◽  
Eiji Yamanaka ◽  
Yoshiyasu Ito ◽  
Kiyoshi Ogata ◽  
Kazuhiko Omote ◽  
...  
Keyword(s):  
Small Angle ◽  
Cross Sectional ◽  
X Ray ◽  
X Ray Scattering ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Ray Scattering

Torsional Stiffness of a Thin-Walled Beam Braced by Pinned or Rigidly Fixed Transverse Diaphragms

1973 ◽  
Vol 15 (5) ◽  
pp. 351-356
Author(s):  
T. Harrison ◽  
J. M. Siddall
Keyword(s):  
Experimental Evidence ◽  
Theoretical Work ◽  
Torsional Stiffness ◽  
Cross Sectional ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Good Agreement

The torsional stiffness of a thin-walled beam of open cross-sectional profile braced by evenly spaced transverse diaphragms is studied. Diaphragms rigidly fixed or attached by frictionless pins are treated and it is seen that, in either case, the only effect is to modify the St Venant torsional constant for the thin-walled beam. The theoretical work is supported by experimental evidence from two braced perspex channels which simulate the two assumed methods of attaching the diaphragms. Good agreement is demonstrated.

scholarly journals Influence of Geometric Parameters on Aerodynamic and Acoustic Performances of Bladeless Fans

2019 ◽  
Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies
Keyword(s):  
Cross Section ◽  
Fluid Dynamic ◽  
Geometric Parameters ◽  
Design Stage ◽  
Air Velocity ◽  
Cross Sectional ◽  
Future Design ◽  
Cross Sectional Profile ◽  
The Cross ◽  
Sectional Profile

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.

Twisting and Bending of Thin-Walled Prismatic Beams of Open Cross-Sectional Profile

1970 ◽  
Vol 12 (2) ◽  
pp. 130-134 ◽  
Author(s):  
T. Harrison
Keyword(s):  
Cross Sections ◽  
Virtual Work ◽  
Cross Sectional ◽  
Transverse Bending ◽  
Prismatic Beam ◽  
Loading System ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Principle Of Virtual Displacements

Previous studies of the behaviour, in generalized co-ordinates, of thin-walled, prismatic beams of open cross-sectional profile have included, explicitly, only the effects of distributed transverse forces, q x and q y, distributed longitudinal forces, q z, and distributed torsional couples, m z. Using the principle of virtual displacements, the work of previous investigators is extended to include, quite generally, the effects of the hitherto neglected distributed couples, m x and m y. The derivation of the differential equation relating to the twisting of an open-section prismatic beam is presented fully whilst those relating to transverse and axial displacements of cross-sections are merely stated. The kinematic and static boundary conditions for a cantilever are also established from the virtual work equations. These show that the free-end shear boundary condition associated with transverse bending which is usually adopted in engineering calculations is inadequate for such a generalized loading system.

scholarly journals CORRELATION BETWEEN FIBER LENGTH, ULTRASTRUCTURE, AND THE LENGTH-TENSION RELATIONSHIP OF MAMMALIAN SMOOTH MUSCLE

1972 ◽  
Vol 52 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Peter H. Cooke ◽  
Fredric S. Fay
Keyword(s):  
Fiber Length ◽  
Ultrastructural Organization ◽  
Cross Sectional ◽  
Dense Bodies ◽  
Tentative Model ◽  
Functional Consequences ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Basic Features ◽  
Relationship Of

The length-tension relationship was determined for strips of guinea pig taenia coli and correlated with the length and ultrastructural organization of the component fibers. The mean fiber length in "stretched" strips (passive ≥ active tension) was 30% greater than that for fibers in "unstretched" strips (active >> passive tension). In stretched fibers the dense bodies and 100 A diameter myofilaments were consolidated into a mass near the center of fibers in cross-sectional profile. The thick myofilaments were segregated into the periphery of the fiber profiles. In unstretched fibers the dense bodies-100 A diameter filaments and the thick myofilaments were uniformly distributed throughout cross-sectional profiles. A tentative model is proposed to account for the change in fiber length and ultrastructural organization that accompanies stretch. The basic features of the model require the dense bodies to be linked together into a network by the 100 A diameter filaments. The functional consequences of stretching the fibers are discussed in relation to the model proposed for this network.

scholarly journals Disentangling the Main Components of Hydromorphological Modifications at Reach Scale in Rivers of Greece

Hydrology ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 22
Author(s):  
Konstantinos Stefanidis ◽  
Anna Latsiou ◽  
Theodora Kouvarda ◽  
Anastasia Lampou ◽  
Nektarios Kalaitzakis ◽  
...  
Keyword(s):  
Habitat Modification ◽  
Ecological Quality ◽  
Cross Sectional ◽  
Habitat Features ◽  
Wide Range ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Main Components ◽  
The Individual ◽  
River Habitat Survey

The Water Framework Directive (WFD) requires from member states to monitor hydromorphological features of rivers in order to assess their ecological quality. Thus, numerous hydromorphological assessment methods have been developed with most of them focusing on the dynamics of hydrology, geomorphology and riparian zone extent. Within the scope of this study, we assessed the hydromorphological features of 106 river reaches distributed among thirteen WFD River Basin Districts (RBDs) to identify the main drivers of hydromorphological perturbation at a national scale. The studied reaches reflect a wide range of natural variability as they include various types of watercourses extending from lowlands to mid-altitude and mountainous systems. We employed the River Habitat Survey (RHS), and we recorded hydromorphological features and modifications in both banks and the channel bed along 500 m for each reach. Then, the Habitat Modification Score (HMS) and the individual sub-scores that indicate the extent of specific modifications (e.g., bridges, fords, weirs, bank reprofiling, bank reinforcement, etc.) were calculated in order to a) assess the severity of the total artificial modification and b) to highlight the most common and severe causes of overall alteration. The results showed that alterations such as reprofiling and reinforcement of banks contributed the most to the total HMS followed by the presence of fords and bridges. Particularly, the bank alterations indicate a serious deterioration of the longitudinal profile of the reaches, while the occurrence of many fords and bridges is the main cause for perturbations that affect locally the stream cross-sectional profile. Overall, these results compile a first nationwide assessment of the hydromorphological status of Greek rivers in line with the WFD and set the basis for further research that will focus on the diversity of stream habitat features as a measure for the overall ecological quality.

Sign in / Sign up

Export Citation Format

Share Document