Bottom Shape Research Articles

A Novel Approach to Estimate the Plastic Anisotropy of Metallic Materials Using Cross-Sectional Indentation Applied to Extruded Magnesium Alloy AZ31B.

In this paper, a methodology is presented for obtaining the plastic anisotropy of bulk metallic materials using cross-sectional indentation. This method relies on spherical indentation on the free edge of a specimen, and examining the out-of-plane residual deformation contour persisting on the cross-section after unloading. Results obtained from numerical simulation revealed that some important aspects of the out-of-plane residual deformation field are only sensitive to the extent of the material plastic anisotropy, and insensitive to strain hardening, yield strain, elastic anisotropy, and the selected displacement threshold value. An explicit equation is presented to correlate the plastic anisotropy with the characteristic parameter of the bottom shape of residual deformation contour, and it is used to uniquely determine the material plastic anisotropy in cross-sectional indentation. Effectiveness of the proposed method is verified by application on magnesium alloy AZ31B, and the plastic anisotropy parameter obtained from indentation and uniaxial tests show good agreement.

RATIO OF THE MAIN DIMENSIONS AND STATIC STABILITY TRADITIONAL PURSE SEINER IN PINRANG

<p><em>The fishing vessel is the main vehicle of the fishermen to go to fishing ground and hauling purse seine especially fishing gear. Pinrang Regency ships traditionally built without calculation of naval architecture. Where the purse seine fishing gear in Pinrang Regency has length 330 m nets with a depth of 36 m. The purpose of this research was to examine the main dimension ratio in particular design and static stability of the vessel purse seine in Pinrang Regency. Method of using a case study on two types of vessels have different relative and analyzed by numerical simulation, calculate the ratio of the main dimensions and static stability. The results of this research are the vessels in Pinrang kasko model has the shape of a round bottom and slim body as well as the ratio of the dimensions of the vessels only L/D purse seine LOA 24 m more than the standard reference of vessels (encircling) in Indonesia and on the value of the static stability by the IMO, with a purse seine vessel Pinrang already has a good stability. However, in both types of vessel purse seine size 20 m that has better stability.</em></p><p><em> </em></p><strong><em>Keywords:</em></strong><em> design, fishing vessel, purse seine, stability</em>

Characters and Significance of Female Breasts in Relation to Female Sexuailty

Purpose: The current study was conducted to obtain information about how a sample of Egyptian women and their husbands look at their own breasts, other women's breasts, and the sexual function of during intercourse. Method: Self-report questionnaire, designed by the investigators. It included 303 married women with an age range of 18-48 years. Aim: It aimed to obtain information about demography, characters of participants own as well as other women's breasts and also the views of their husbands.Results: The most common shape was Full on top breast with reddish brown areolas. The commonest bra size was medium. Most participants thought that large breasts are uncomfortable and only (11.55%) of them would like to have a augmentation surgery. Full on top & bottom shape was the preferred shape. Most participants said that size does affect female attractiveness. A majority of responders said that their husbands were satisfied with the size and shape of their breasts. Participants would like their husbands to stimulate their breasts during coitus orally and manually. The ability to reach orgasm by stimulation only during coitus was reported by (15.51%) of participants.Conclusion: The significance of female breasts as a sexual organ must be emphasized especially to the male partner. Some women can reach orgasm by the mere stimulation of their breasts. The study outlined the importance of oral and manual stimulation of during foreplay.

A novel and rapid fabrication method for a high fill factor hexagonal microlens array using thermal reflow and repeating spin coating

This paper presents an innovative process for the fabrication of a high fill factor microlens array using thermal reflow and repeating spin coating. The repeated spin coating method creates a hexagonal microlens array after the thermal reflow processes as an alternative to the expensive gray-mask and longtime electroplating method. The first, the round base and hexagonally arranged array, precisely define the bottom shape of the liquid photoresist, and a tall hemispherical microlens array with a small radius of curvature is fabricated during the photoresist thermal reflow process. The second, the surplus photoresist, is then rotated at high velocity using a spinner. The micro-plano-convex microlens molds are then finished. The polydimethylsiloxane (PDMS) microlens array is fabricated using a replica molding process. The experimental results show that a high fill factor hexagonal PDMS microlens array is successfully fabricated. The fabricated microlens array has good surface roughness. The proposed fabrication method facilitates mass production and gives increased luminance efficiency and luminance power efficiency to produce a high fill factor microlens array that is suitable for use in the light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs).

ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher

A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.

Geological conditions for continental tight oil formation and the main controlling factors for the enrichment: A case of Chang 7 Member, Triassic Yanchang Formation, Ordos Basin, NW China

Abstract The Chang7 Member of the Triassic Yanchang Formation in the Ordos Basin is a typical continental tight oil province. The geological conditions and the main controlling factors for the formation of tight oil province in Chang 7 Member were studied based on extensive core analysis data, laboratory simulation tests and practical work of tight oil exploration and development in the basin. The tight oil in the Chang 7 Member is characterized by wide distribution, excellent source rock conditions, tight sandstone reservoirs, complicated pore-throat structure, poor physical properties, high oil saturation, high quality oil, and low pressure coefficient. During the depositional period of Chang7 Member, the bottom shape of the basin was steep at southwest and gentle at northeast, the tectonic movements were active, favorable for the deposition of source rock and reservoir; the widespread high quality source rock can provide sufficient oil supply for the large tight oil province; the large scale sand bodies provide good reservoir condition for the large tight oil province; the abundant structural fractures in the tight reservoir act as pathways for tight oil migration; and the stable deposition and tectonic evolution of the basin provide good preservation conditions for the tight oil province. The main controlling factors of Chang7 Member tight oil enrichment are as follows: (1) good configuration of source rock and reservoir and constant charging are the key to the formation of the tight oil province; (2) abundant micro-scale pores are the premise of tight oil enrichment; (3) strong and sustained charging guarantees the enrichment and high yield of oil in the tight reservoirs.

Определение формы объекта в ультразвуковой дефектоскопии с помощью кусочно-линейного представления

A new way of representing the shape of an object bottom using non-destructive ultrasonic testing techniques is proposed. The image of the examined object’s bottom is represented by a set of short segments. Each of these segments is a tentative ultrasonic signal reflection place. The segment intersection place is the place at which the ultrasonic signal is reflected. An algorithm for erasing segments that are not a place at which the ultrasonic signal is reflected from the bottom is proposed. This erasing is performed using elementary logic and takes a short time to do. The segments that remain after erasing are the places at which the ultrasonic signal is reflected from the bottom. Since the medium is constant and remains unchanged, it becomes possible to accumulate the obtained echo signals. Owing to this feature, the synthetic aperture method is used. An ultrasonic pitch-catch sensor moving with a constant step is used. Each signal is saved in memory. The total number of steps is N. After obtaining the echo oscillograms, the signals are subjected to processing. It is assumed that strong attenuation of ultrasound is observed in the object being examined, due to which a complex modulated signal is used. Computer-aided simulation was carried out. A new shape of the object bottom is used in each computer model. The proposed method for visualizing the object’s bottom shape is compared with a tomogram. A homogeneous medium with strong damping is used in the computer model. Experiments with a new object bottom shape in each of them are carried out. The tomogram and the proposed method for visualizing the object bottom shape are compared with each other. Water was used in the experiment as the medium. The obtained results have been compared with each other, and conclusions have been drawn. In many cases, the new representation of an object gives a clearer picture.

Numerical Modeling of Flow over an Ogee Crested Spillway under Radial Gate: VOF and MMF Model

The present research work shows the simulation of the gated flow over an ogee crested spillway for one of water reservoir. The average velocities and Froude Number analysis at various gate openings gives a better insight of flow behavior. Also, the simulations were carried out by changing the gate bottom shape. The STAR CCM+ CFD tool is used to solve the fluid flow performance. The flow parameters near the bottom of the gate have been studied with two types of fluid flow models i.e. Volume of Fluid (VOF) and Multi-Mixture Fluid Models. The use of Volume of Fluid (VOF) multiphase model together with RNG k-e turbulence for the simulation, gives the excellent agreement between the experimental and numerical data. The spillway performance of the gated flow at various gate openings resembles with the actual flow behavior. The applicability of the CFD model to simulate the gated flow over ogee crested spillway is reviewed. The computational model study showed that CFD can be useful in hydraulics structures for designing of various reservoirs. This numerical model gives significant advantage in practice, in terms of parametric studies

수치해석을 이용한 바닥공조 시스템의 공기환경 평가

In order to improve air quality of indoor environment, studies of the underfloor air distribution (UFAD) system for application in buildings are actively in progress based on temperature and air flow distribution. However, although the age of air is the major evaluation parameter, there has been very little study on this parameter for the UFAD system. In this study, we investigated the age of air to reach the air diffuser, which is installed at the bottom of the interior by the UFAD system. Computational fluid dynamics simulations showed no regular pattern to the maximum value of the age of air in accordance with air flow rate and the velocity at air diffuser. These factors can be deduced from air movement by considering that air emitted from air conditioners was rotated according to the bottom shape of the floor, and then, the age of air in the rotation center was increased. The average age of air of internal interior was reduced considerably as the flow velocity at the underfloor air diffuser was increased from 0.5 m/s to 1.0 m/s However, the age of air was not substantially affected with change in the air volume. Moreover, when the flow velocity at the underfloor air diffuser was higher than 1.0 m/s, the age of air showed no significant difference with change in air volume or height of measurement. These results imply that indoor air quality is more substantially influenced by flow velocity than air volume, and the appropriate flow velocity is 1 m/s or more.

Micro-bottom shape effects on the misaligned herringbone grooved axial piston bearing with a new parallel algorithm

This paper presents a group of elastic Hydrodynamic lubrication (EHL) analyses to evaluate the effects of micro-bottom shape on the performance of misaligned herringbone grooved axial piston bearing. Due to the time-consuming elastic Hydrodynamic lubrication (EHL) tasks introduced in herringbone grooves, complex bottom shape, rotation combined axial movement, and misalignments require high-speed computation. So a new parallel elastic Hydrodynamic lubrication (EHL) numerical algorithm is proposed, which exhibits higher computing speed than the normal successive over relaxation (SOR) method. The results suggest the bottom shapes of herringbone grooves significantly affect the lubrication performance of misaligned herringbone grooved axial piston bearing. Rectangle and left triangle bottom shapes involve a micro-step bearing effect which can significantly improve the lubrication performance, comparing to semiellipse, isosceles triangle, and right triangle bottom shapes.

Comparing rock shape models in grounding damage modelling

Groundings are among the most common and destructive maritime accidents. Sea bottom shape influences greatly what kind of damage the ship structure suffers and whether this leads to loss of water tightness.Sormunen et al. [21] presented and statistically compared rock models used in grounding damage analysis with detailed bottom shape data from two Finnish harbour fairways. The results were promising in terms of statistical fit especially for the binormal rock model, which also showed a wide range of flexibility in representing different types of sea bottom shapes. However, this measure does not explicitly tell if the model rock in grounding damage analysis results in similar damage size as real rocks cause. To test this, this paper develops a framework for studying, testing and evaluating rock models in terms of resulting grounding damage. FEM is used to analyse and compare grounding damage of rock models to the actual rock using otherwise identical grounding scenarios. Analysis is performed for four different real rocks with each rock being modelled with four different analytical rock models as well.The results show that rock models with good statistical fit did not necessarily result in similar grounding energy compared to results using the real rock. Differences in energy are caused especially by the rougher surface of the real rocks. For the similarity in rock area and the damaged ship structure element volume the results are much better, especially for the binormal model. As such another criteria for evaluating rock models for grounding damage analysis is needed. The results show that the damaged material volume is strongly linearly dependent on the rock area- and volume metrics. A similar linear dependency exists between the damaged volume and the energy dissipated in grounding. Knowledge of these relationships can be used towards estimating grounding damage of ships in future investigations, but rock surface unevenness should be evaluated as well.

Flow pattern control in continuous slab casting moulds: physical modelling and plant trials

Full-scale water modelling studies combined with nail-dipping industrial trials at Shougang Jingtang (SGJT) Works were carried out in order to investigate the parameters that influence flow patterns in the continuous slab casting mould. The effects of casting speed/mould width combinations, argon bubbling flow rates, submerged entry nozzle (SEN) immersion depths and SEN geometries (port angle and bottom shape) on the flow patterns were examined. A CMI factor defined as casting speed/mould width ratio index is put forward to describe the combined effect of these parameters on the fluid flow patterns in the mould. The results show that the CMI and argon injection rates are the dominant factors that determine the flow pattern. On the basis of the results from this study, critical argon flow rates for different casting combinations have been evaluated. These findings provide operating guidelines for generating optimal flow patterns based on double roll flow with appropriate surface velocities in continuous slab casting moulds. On the basis of these considerations, slab quality at SGJT Works was substantially improved and the percentage of flow pattern-related sliver defects in cold rolled products was decreased from 4.5 to 2.3%.

Variations of the ionospheric parameters and vertical electron density distribution at the northern edge of the EIA from 2010 to 2015 along 95°E and comparison with the IRI-2012

The vertical electron density profiles over Dibrugarh (27.5°N, 95°E, 43° dip) a low mid latitude station normally located at the northern edge of the EIA for the period of July 2010 till October 2015 are constructed from the measured bottom side profiles and ionosonde-GPS TEC assisted Topside Sounder Model (TSM) topside profiles. The bottom side density profiles are obtained by using POLAN on the manually scaled ionograms. The topside is constructed by the modified ionosonde assisted TSM model (TaP-TSM assisted by POLAN) which is integrated with POLAN for the first time. The reconstructed vertical profile is compared with the IRI predicted density profile and the electron density profile obtained from the COSMIC/FORMOSAT radio occultation measurements over Dibrugarh. The bottom side density profiles are fitted to the IRI bottom side function to obtain best-fit bottom side thickness parameter B0 and shape parameter B1. The temporal and solar activity variation of the B-parameters over Dibrugarh are investigated and compared to those predicted by IRI-2012 model with ABT-2009 option. The bottom side thickness parameter B0 predicted by the IRI model is found to be similar to the B0 measured over Dibrugarh in the night time and the forenoon hours. Differences are observed in the early morning and the afternoon period. The IRI doesn’t reproduce the morning collapse of B0 and overestimates the B0 over Dibrugarh in the afternoon period, particularly in summer and equinox. The IRI model predictions are closest to the measured B0 in the winter of low solar activity. The B0 over Dibrugarh is found to increase by about 15% with solar activity during the period of study encompassing almost the first half of solar cycle 24 but solar activity effect was not observed in the B1 parameter. The topside profile obtained from TaP profiler is thicker than the IRI topside in equinox from afternoon to sunrise period but is similar to the IRI in summer daytime. The differences in the bottom side may be attributed to the non-inclusion of ground measurements from 90°E to 100°E longitude in the ABT-2009 model while differences in the topside could be due the non-uniform longitudinal distribution of topside sounder profiles data and the stronger fountain effect in this longitude.

Experimental study of the effect of drift angle on a ship-like foil with varying aspect ratio and bottom edge shape

A ship-like foil geometry with different aspect ratios and bottom edge shapes are tested experimentally with several drift angles (0–10°), and two Froude numbers (0.1 and 0.2). The geometry is a modified version of the foil Eppler E836 that is extruded in the span direction to make it a 3D geometry. The aspect ratios are 0.1, 0.2 and 0.3. Two different bottom edge shapes are tested: a perfectly sharp bottom edge and a rounded bottom edge. Lift, drag and yaw moment is measured. The result is presented both as raw data and data fitted polynomial functions. The experimental results are compared to simplified models for lifting surfaces, along with some discussion regarding the physics of a drift-induced forces. The simplified models do not fit the experimental data very well, but the comparison is used to discuss the importance of different physical effects. The result from the experiments show that both the aspect ratio and the shape of the bottom edge is very important. Froude number effects on lift and lift-induced drag are seen to be very small, for the two Froude numbers tested in this experiment, while the yaw moment and center of pressure is affected.

Shape design of the bottom plug used in a 3-way reversing valve to minimize the cavitation effect

In the washing machines used for the pressure-cleaning of automotive parts, a pair of 2-way valves frequently reverses the flow direction of the water to spray high-pressurized clean water to remove all oil and dirt from machined engine and transmission blocks. Although this valve system is widely used due to its competitive price, its application can be restricted by the surging effect of a pressure ripple caused by inaccurate valve control during the rapid changes in water flow. As an alternative, a 3-way reversing valve can be used to replace the valve system, to provide rapid and accurate changes in water flow direction without the need of a precise control device. During the use of this alternative valve, however, a cavitation effect often occurs due to a complicated bottom plug shape. In this study, the cavitation index and POC (percent of cavitation) were introduced to numerically evaluate the cavitation effect. To minimize the cavitation effect, an optimal shape design was carried out via parametric study, in which a simple CAE-model was applied in order to avoid time-consuming multi-phase fluid-flow analysis and also to avoid the need for convergence, which is difficult to achieve. A full-factorial DOE and an artificial neural network model provided the optimal values required for a status of nocavitation occurrence: waist length, tail length and POC at 6.50 mm, 6.69 mm and 27%, respectively.

Performance validation and optimization of a dual coaxial-cylinder ocean-wave energy extractor

A point-absorber wave-energy extractor is developed, consisting of a dual coaxial-cylinder system, with the inner cylinder tension-tethered and an outer cylinder (floater) oscillating vertically. A permanent magnet linear generator (PMLG) is used as a power take-off (PTO) capturing wave energy from the relative motion of the two cylinders. The mathematical modeling of the system includes the coupling effects of the cylinder hydrodynamics and the PMLG behavior. It gives a rational and effective way of providing performance predictions and directions for optimization. The flat bottom shape of the floater is modified into a needle-like curved shape to minimize viscous losses, which leads to three-times increase in floater response, compared with the flat-bottom geometry and thus improved wave-energy capture. The behavior of the PTO in the presence of an appropriate supporting structure for the coaxial cylinders are investigated, and optimal operating conditions for energy extraction and mechanical to electrical conversion efficiency are determined. Experimental results of this coupled system in regular waves confirm the validity of the theoretical predictions and soundness of the engineering design. Optimizing the floater bottom shape and the operating conditions for energy extraction lead to a two-times increase in overall efficiency, even without any active control.

測長SEMによるゲートパターン裾引きの三次元形状推定

In the semiconductor manufacturing, a critical dimension scanning electron microscope (CD-SEM) is widely used as a process monitoring tool. As design rules become finer and denser in recent years, needs for controlling three-dimensional (3D) shape in addition to one- and two-dimensional size of the pattern, such as the CD value, have risen for the process monitoring. In this paper, we propose a novel approach for estimating 3D bottom footing shape of gate patterns from two SEM images, with 5 and 10 degree tilt. Bottom footing shape can provide valuable clues for inspecting and analyzing electrical properties of semiconductor devices. The proposed method realizes a highly precise estimation by combination of existing inverse stereo matching (ISM) method with a bottom footing index, which is the width of the range where the bottom footing exists. The measured shape of ISM method is represented with a cubic spline curve and is then corrected by transformation of the curve on the basis of the pre-learning relationship between bottom footing index and curve parameters. The proposed algorithm was verified with 12 samples of gate pattern. As the results of the evaluation, the average and deviation (three sigma) of the measurement error in the part of bottom footing were 1.3nm±1.0nm. The proposed method can effectively provide an accurate 3D shape and is expected to be applied to the process monitoring in actual production lines.

Numerical Investigation of the Effect of Bottom Shape on the Flow Field and Particle Suspension in a DTB Crystallizer

The influence of the bottom shape on the flow field distribution and particle suspension in a DTB crystallizer was investigated by Computational Fluid Dynamics (CFD) coupled with Two-Fluid Model (Eulerian model). Volume fractions of three sections were monitored on time, and effect on particle suspension could be obtained by analyzing the variation tendency of volume fraction. The results showed that the protruding part of aWtype bottom could make the eddies smaller, leading to the increase of velocity in the vortex. Modulating the detailed structure of theWtype bottom to make the bottom surface conform to the streamlines can reduce the loss of the kinetic energy of the flow fluid and obtain a larger flow velocity, which made it possible for the particles in the bottom to reach a better suspension state. Suitable shape parameters were also obtained; the concave and protruding surface diameter are 0.32 and 0.373 times of the cylindrical shell diameter, respectively. It is helpful to provide a theoretical guidance for optimization of DTB crystallizer.

Analysis of the Building Envelope Influence to Building Energy Consumption in the Cold Regions

Building envelope thermal conduction is dominant in the cold regions, the thermal performance of the building envelope plays a very important role in reducing building energy consumption. In cold areas, the annual air conditioning heating energy consumption of public buildings, there are about 50% consumed by the heat transfer of building envelope. Therefore, the study on energy saving building envelope is very important. This paper start from the building shape coefficient and the heat transfer coefficient of the building envelope, using DEST energy simulation software to analyze the office building energy consumption. Choosing the typical cold B region Shenyang, establishing the Office model, analysis the influence of office building envelope heat transfer coefficient to indoor equipment energy consumption. Pointing out that the architectural design and planning should try to select the building bottom shape close to a circle or a square, and try to select middle-high-rise buildings to reduce building shape coefficient. Generally, in cold B region the heat transfer coefficient K≤0.5W/m2 • K, the windows and roofs try to select low heat transfer coefficient material, by reducing the heat transfer coefficient to achieve an insulating effect.

Estimating sea bottom shapes for grounding damage calculations

Groundings are among the most common and serious maritime accidents. The shape of the sea bottom is one of the important factors that determine the extent of grounding damage on ships, including loss of watertightness. This paper presents a four-step methodology for mathematically analyzing sea bottom shapes, where individual peaks are identified and isolated from larger datasets. To these individual peaks mathematical models are fitted and the goodness of the fit is evaluated.The aim is to develop mathematical rock models that can be used in grounding damage analysis. The method is applied to bottom topography data from the two busiest tanker harbors in Finland. As potential mathematical rock models common assumptions found in literature as well as new suggestions are used.It was observed that rocks vary in shape and size locally as well as between different geographical areas. This highlights the need to have rock models that are flexible enough to model a wide range of sizes and shapes so that the local conditions can be taken into account. This includes modeling asymmetrical shapes, which is not taken into account in the current models. The analysis results suggest using a binormal function to describe the bottom shape: This model gives overall better goodness-of-fit test results than the cone and polynomial models. In the data the binormal model can model well the also the bottom shapes where the polynomial and conical models had a good fit in statistical terms. Although the paper discusses data from the Gulf of Finland, the framework for analyzing bottom shapes is expected to be applicable to other sea areas as well.