Horizontal Cross-section Research Articles

Three-dimensional macro/mesoporosity developments in polydimethylsiloxane

ABSTRACTMacro/mesoporous polydimethylsiloxanes (PDMS) were prepared with the purpose of vascular grafts. Oligoester-containing semi-interpenetrating polymer networks (semi-IPNs) can be used as precursors for generation of networks with tunable pore sizes. Novel poly(methyl methacrylate)/PDMS semi-IPNs were prepared by varying structural parameters. Extraction of uncrosslinked oligoester subchains from semi-IPNs was investigated. To tailor the morphology of porous structure, influence of some factors including porogen type, different polymerization conditions, monomer type, and concentration, crosslinking agent concentration were studied. PDMS networks were examined by field emission scanning electron microscopy. A uniform porous structure with interconnected pores was detected in horizontal and vertical cross sections of PDMS.

Hells Bells – unique speleothems from the Yucatán Peninsula, Mexico, generated under highly specific subaquatic conditions

We here report on a type of meter-sized pendant speleothem growing under water in the submerged El Zapote sinkhole (cenote) west of Puerto Morelos on the Mexican Yucatán Peninsula. These conical, mantle-shaped downward expanding and diverging calcareous structures, here termed as Hells Bells, are yet unreported in the scientific literature. They are characterized by bell- or trumpet shaped longitudinal and circular, elliptical or horse-shoe-like horizontal cross-sections. Hells Bells grow downward, based on the downward divergence of the structures and the horizontally laminated internal texture of both blade-shaped spar calcite and microspar laminae. Age dating confirms that Hells Bells are young (<4500yr) and formed in a subaquatic environment. They grow under lightless conditions in a stratified water body, which is characterized by a fresh water body overlying a salt water body with a stagnant transition zone (halocline) of several meters. We hypothesize that the growth of these structures is mediated by specific physical and biogeochemical conditions above and in the halocline. Stagnant hydraulic conditions led to extensive diffusion profiles of several nutrients including calcium originating from the salt water body. Dissolved organic carbon from the fresh water is microbially oxidized in the upper part of the halocline, where a distinct redox zonation was identified from oxic to anoxic conditions. Degradation processes combined with slightly alkaline pH values as well as the diffusive transport of calcium into this zone may induce an increase in calcite oversaturation. Phylogenetic analysis of the community on the surface of the Hells Bells suggests the presence of microorganisms involved in the nitrogen-cycle, from which some potentially have the capability to increase the pH by autotrophic growth and denitrifying activity, thus supporting calcite precipitation. The growth of Hells Bells is strictly dependent on the elevation of the halocline. This offers a wide potential for the use of Hells Bells as archives of paleo-hydrological conditions during the Holocene, e.g. the variation of thickness of the fresh water lens on the Yucatán Peninsula.

Integrating non-colocated well and geophysical data to capture subsurface heterogeneity at an aquifer recharge and recovery site

Geophysical data have proven to be very useful for lithological characterization. However, quantitatively integrating the information gained from acquiring geophysical data generally requires colocated lithological and geophysical data for constructing a rock-physics relationship. In this contribution, the issue of integrating noncolocated geophysical and lithological data is addressed, and the results are applied to simulate groundwater flow in a heterogeneous aquifer in the Prairie Waters Project North Campus aquifer recharge site, Colorado. Two methods of constructing a rock-physics transform between electrical resistivity tomography (ERT) data and lithology measurements are assessed. In the first approach, a maximum likelihood estimation (MLE) is used to fit a bimodal lognormal distribution to horizontal crosssections of the ERT resistivity histogram. In the second approach, a spatial bootstrap is applied to approximate the rock-physics relationship. The rock-physics transforms provide soft data for multiple point statistics (MPS) simulations. Subsurface models are used to run groundwater flow and tracer test simulations. Each model's uncalibrated, predicted breakthrough time is evaluated based on its agreement with measured subsurface travel time values from infiltration basins to selected groundwater recovery wells. We find that incorporating geophysical information into uncalibrated flow models reduces the difference with observed values, as compared to flow models without geophysical information incorporated. The integration of geophysical data also narrows the variance of predicted tracer breakthrough times substantially. Accuracy is highest and variance is lowest in breakthrough predictions generated by the MLE-based rock-physics transform. Calibrating the ensemble of geophysically constrained models would help produce a suite of realistic flow models for predictive purposes at the site. We find that the success of breakthrough predictions is highly sensitive to the definition of the rock-physics transform; it is therefore important to model this transfer function accurately.

Alternatively permutated conic baffles generate vortex flow field to improve microalgal productivity in a raceway pond

Alternatively permutated conic (APC) baffles were proposed to generate vertical and horizontal vortex flow to intensify mixing and mass transfer in a raceway pond. Both clockwise vortexes were generated before and after conic baffles in the main stream to increase perpendicular velocity by 40.3% and vorticity magnitude by 1.7 times on vertical cross section. Self-rotary flow around conic baffles and vortex flow among conic baffles were generated to increase perpendicular velocity by 80.4% and vorticity magnitude by 4.2 times on horizontal cross section. The bubble generation time and diameter decreased by 25.5% and 38.7%, respectively, while bubble residence time increased by 84.3%. The solution mixing time decreased by 48.1% and mass transfer coefficient increased by 34.0% with optimized relative spacing (ε) and height (ω) of conic baffles. The biomass productivity of Spirulina increased by 39.6% under pure CO2 with APC baffles in a raceway pond.

Microstructural investigation on air void properties of porous asphalt using virtual cut section

The microstructure properties of asphalt mixtures reflect the structural and functional performance of asphalt mixtures. Thus, numerous imaging methods are developed including destructive and non-destructive methods to uncover the internal structure properties of asphalt mixtures. However, accurate analysis of internal microstructure properties is challenging. This study used a non-destructive method employing virtual cut section (imaging technique) to analyze the air void properties of laboratory-fabricated porous asphalt. Conventionally, the investigation of internal structure properties particularly on vertical section requires the sample to be cut (destructive method) into several sections. This method causes defects to the sample and limits the amount of data that can be extracted from the image. The imaging technique designed in this study provides comprehensive understanding of the distribution and properties of air voids from different angles within the compacted sample of porous asphalt. The void properties in porous asphalt should be assessed accurately to ensure effectiveness of water permutation through the porous structure and acoustic function of the mixture. The compacted samples were X-rayed and virtually analyzed into various cut sections. The void properties were characterized in terms of the content, number, shape, and size of voids. Results indicate that air voids within the porous asphalt are homogeneously distributed with an elongated shape; this characteristic indicates high void connectivity. The vertical cross-section analysis justifies the characteristics of air voids in the conventional analysis of horizontal cross section.

Analysis of volumetric properties of bituminous mixtures using cellular phones and image processing techniques

This study aims to develop the microanalysis of the bituminous mixtures using cellular phone images (CPI) and image processing techniques (IPT). A new methodology and scheme was developed for faster and accurate procedure to compute volumetric design parameters; voids in mineral aggregate (VMA), voids in total mix (VTM), and voids filled with asphalt (VFA) using CPI and IPT instead of the conventional methods. Five types of cellular phones with different camera resolutions were used to analyze the horizontal cross section (face) of hot mix asphalt slices. A cellular phone digital mapping frame for microstructure of the bituminous mixture for data collection was designed and implemented. New models for computations of volumetric design perimeters (VMA, VTM, and VFA) were developed. Results showed that the best cellular phone for microanalysis of the bituminous mixture is type D, even though it does not have the highest resolution, and the best height of capturing the images is 35 cm.

Deep structure of Kamchatka according to the results of MT sounding and seismic tomography

The key features in the distribution of geoelectric and velocity heterogeneities in the Earth’s crust and the upper mantle of Kamchatka are considered according to the data of deep magnetotelluric sounding and seismotomography. Their possible origin is discussed based on the combined analysis of electric conductivity and seismic velocity anomalies. The geoelectric model contains a crustal conducting layer at a depth of 15–35 km extending along the middle part of Kamchatka. In the Central Kamchatka volcanic belt, the layer is close to the ground surface to a depth of 15–20 km, where its conductivity considerably increases. Horizontal conducting zones with a width of up to 50 km extending into the Pacific Ocean are revealed in the lithosphere of eastern Kamchatka. The large centers of current volcanism are confined to the projections of the horizontal zones. The upper mantle contains an asthenospheric conducting layer that rises from a depth of 150 km in western Kamchatka to a depth of 70–80 km beneath the zone of current volcanism. According to the seismotographic data, the low- and high-seismic-velocity anomalies of P-waves that reflect lateral stratification, which includes the crust, the rigid part of the upper mantle, the asthenospheric layer in a depth range of ~70–130 km, and a high-velocity layer confined to a seismofocal zone, are identified on the vertical and horizontal cross sections of eastern Kamchatka. The cross sections show low-velocity anomalies, which, in the majority of cases, correspond to the high-conductivity anomalies caused by the increased porosity of rocks saturated with liquid fluids. However, there are also differences that are related to the electric conductivity of rocks depending on pore channels filled with liquid fluids making throughways for electric current. The seismic velocity depends, to a great extent, on the total porosity of the rocks, which also includes isolated and dead-end channels that can be filled with liquid fluids that do not contribute to the electric-current transfer. The data on electric conductivity and seismic velocity are used to estimate the porosity of the rocks in the anomalous zones of the Earth’s crust and the upper mantle that are characterized by high electric conductivity and low seismic velocity. This estimate serves as the basis for identifying the zones of partial melting in the lithosphere and the asthenosphere feeding the active volcanoes.

Verification and Updating of the Database of Topographic Objects with Geometric Information About Buildings by Means of Airborne Laser Scanning Data

Abstract Airborne laser scanning data (ALS) are used mainly for creation of precise digital elevation models. However, it appears that the informative potential stored in ALS data can be also used for updating spatial databases, including the Database of Topographic Objects (BDOT10k). Typically, geometric representations of buildings in the BDOT10k are equal to their entities in the Land and Property Register (EGiB). In this study ALS is considered as supporting data source. The thresholding method of original ALS data with the use of the alpha shape algorithm, proposed in this paper, allows for extraction of points that represent horizontal cross section of building walls, leading to creation of vector, geometric models of buildings that can be then used for updating the BDOT10k. This method gives also the possibility of an easy verification of up-to-dateness of both the BDOT10k and the district EGiB databases within geometric information about buildings. For verification of the proposed methodology there have been used the classified ALS data acquired with a density of 4 points/m2. The accuracy assessment of the identified building outlines has been carried out by their comparison to the corresponding EGiB objects. The RMSE values for 78 buildings are from a few to tens of centimeters and the average value is about 0,5 m. At the same time for several objects there have been revealed huge geometric discrepancies. Further analyses have shown that these discrepancies could be resulted from incorrect representations of buildings in the EGiB database.

Diurnal Wind, Relative Humidity and Temperature Variation in the Stellenbosch-Groot Drakenstein Wine-Growing Area

Numerical simulations were performed for 2000-02-03 and 2000-02-04 over the Western Cape in order to observe the alternating sea and land breeze circulation and its effects on diurnal relative humidity and temperature variation, as well as to identify wine-growing areas characterised by high humidity and cool temperature during the maturation period. The Regional Atmospheric Modelling System (RAMS version 4.3) was used at a 1 km resolution. The study domain for the simulation covered a small area from False Bay up to 35 km from the coast. Results are presented using horizontal cross-sections at surface level as well as two south-north cross-sections at longitudes l8°40'E and l8°47'E in order to examine vertical profiles of the atmosphere above the Stellenbosch I Groot Drakenstein winegrowing area. Modelled results agreed with observed data in the vineyards. The sea breeze penetrated at least 35 km inland, but the cooling effect declined rapidly with distance from the sea. Temperature differences between southern and northern slopes near the sea could be significant enough to be important for viticulture.

Effect of the skid trail cross section and horizontal alignment on forest soil physical properties

Horizontal alignment and cross section characteristics of a skid trail in a ground-based skidding system including curves, wheel ruts and cross slope can impact on the forest soil. In this study the measurement of cross section and vertical alignment of skid trail in Bahramnia forestry plan was done using a levelling instrument. Horizontal alignment of skid trail including straight routes and curves was taken using polar methods. A 3D map of skid trail was produced in AutoCAD Civil3D software. Soil bulk density was measured after sampling the soil with a core sampler. Results showed that in straight routes, soil bulk density increased by increasing the cross slope of skid trail. Moreover, soil porosity decreased with the increasing cross slope. There was a significant difference between cross slopes in soil moisture. On curves, maximum bulk density occurred when the cross slope was 10%. Findings about soil porosity and moisture on curves of skid trails were similar to those of straight routes. Based on our findings, soil bulk density in wheel ruts was significantly lower than that in the middle part of skid trail. Soil bulk density in the silty soil texture of studied skid trails was a little more than ideal bulk density, so it cannot affect and restrict root growth.

Comparison on mechanical anisotropies of selective laser melted Ti-6Al-4V alloy and 304 stainless steel

Near-fully dense Ti-6Al-4V and 304 stainless steel samples have been produced applying selective laser melting (SLM) in the present work. The microstructures, textures and microhardnesses on horizontal and vertical cross sections, as well as the tensile properties of horizontally and vertically SLMed samples are investigated. It is found that the microstructures of the two SLMed alloys are mainly composed of hexagonal close-packed (HCP) martensitic phase or face-centered cubic (FCC) austenitic phase within columnar structures in Ti-6Al-4V alloy and 304 stainless steel, respectively. For both SLMed alloys, the tensile properties and microhardnesses show anisotropic though the textures are weak. Especially, the Ti-6Al-4V samples show even stronger anisotropic mechanical properties compared with 304 stainless steel. The higher length-width ratios of the columnar structures, rather than the weaker textures or the less symmetry of HCP crystal structure in SLMed Ti-6Al-4V are believed to be responsible for the stronger mechanical anisotropies. As expected, heat treatment is an effective method to eliminate columnar structures and leads to nearly isotropic mechanical properties.

Constant Property Newtonian Fluid Flow and Heat Transfer overCascaded Fins

Turbulent flow and heat transfer characteristics were studied and analyzed numerically for a constant property Newtonian fluid flowing through a two-dimensional horizontal rectangular cross section channel with staggered, transverse cascaded rectangular-triangular fins (CRTFs) and a constant temperature along both walls. The governing equations based on model used to describe the turbulence phenomenon, are solved by the finite volume method using the SIMPLEC-algorithm. Computations were carried out in the fully-developed regime for different Reynolds numbers, and geometric locations. In particular, velocity and temperature fields, skin friction coefficient, and local and average Nusselt numbers were obtained. This study can be a real application in the field of heat exchangers and air plane solar collectors.

Terahertz Imaging of Three-Dimensional Dehydrated Breast Cancer Tumors

This work presents the application of terahertz imaging to three-dimensional formalin-fixed, paraffin-embedded human breast cancer tumors. The results demonstrate the capability of terahertz for in-depth scanning to produce cross section images without the need to slice the tumor. Samples of tumors excised from women diagnosed with infiltrating ductal carcinoma and lobular carcinoma are investigated using a pulsed terahertz time domain imaging system. A time of flight estimation is used to obtain vertical and horizontal cross section images of tumor tissues embedded in paraffin block. Strong agreement is shown comparing the terahertz images obtained by electronically scanning the tumor in-depth in comparison with histopathology images. The detection of cancer tissue inside the block is found to be accurate to depths over 1 mm. Image processing techniques are applied to provide improved contrast and automation of the obtained terahertz images. In particular, unsharp masking and edge detection methods are found to be most effective for three-dimensional block imaging.

Ultrasonic method for monitoring the clotting process during whole blood coagulation

The purpose of this work was to develop a multichannel ultrasonic measurement method for monitoring a spatially non-uniform blood clotting process. This novel method is based on simultaneous multi-channel measurements of ultrasound propagation velocities in different horizontal cross-sections of clotting blood.The most common method used for determining blood-clotting time is the capillary tube method. For this purpose ultrasonic methods based on measurements of the velocities of ultrasound waves in clotting blood are also used. Measurement results essentially depend on the propagation path of the ultrasonic wave in a blood sample. The ultrasound velocity changes as fresh blood transforms into clot plus serum. The objective of this work was to develop a measurement method that allows one to measure ultrasound velocity and its evolution in time and space in an evolving clot while avoiding the influence of serum.To achieve this objective, a novel method has been proposed that is based on ultrasound propagation velocity measurements in different horizontal cross-sections of clotting blood using a pulse-echo mode. Such a technique enables researchers to monitor the clotting process and a clot’s spatial structure, which are different in different layers due to the influence of gravity. The four-channel measurement chamber utilizing this method has been designed and manufactured. For the generation and reception of ultrasonic waves of high frequency, wide band (3–20MHz at −6dB) ultrasonic transducers were developed. To verify that the multi-channel measurement system was operational, a special procedure based on monitoring of a polymerisation process in the acrylamide solution was proposed.Performance of the developed method was investigated by measuring clotting blood (sample volumes of less than 0.6ml) at the frequency of 12MHz. The results revealed that a clot structure indeed varies within a blood sample due to the influence of gravity; clotting times are different in different horizontal layers of the clot and range from 9 to 15min, defined by the standard capillary method. Clotting times are determined precisely from abrupt increases in ultrasound velocity. Uncertainty of the ultrasound velocity measurements was less than ±0.05m/s. The experiments were performed at 36.90±0.01°C.The proposed method may be exploited for monitoring polymerisation reactions in the chemistry field, as well.

Numerical Simulation of Hydrodynamic for Abrupt Bathymetry in Palu River Estuary

The failure of numerical simulation for hydrodynamic model in abrupt bathymetry zone is one of the obstacles in solving environmental problems in coastal zone. The research aims to make three dimensional hydrodynamic model in Palu river estuary that has abrubt bathymetry using ECOMSED. The simulation was conducted on horizontal and vertical cross section with the boundary condition of model, i.e. the depth data was used at the bottom of the river and the sea, river discharge at upstream and tide constituents at downstream. Input data and interpolation program was made in solving error problem. Run time error occurred during simulation, therefore, experimental method was used by modifying input data and increasing the number of grid and time step resolution to make calculation became stable. The results revealed that the influence of tidal current in Palu river estuary is smaller than the influence of river discharge and the temperature is mainly distributed westward on the horizontal cross section. While on the vertical cross section, the direction of temperature distribution follows the current movement pattern based on the overlay between current and temperature distribution. The calculated surface elevation and current velocity on the vertical cross section well suits with the secondary data obtained from hydro oceanographic office and observed current velocity.

Behavior of a Jet Issuing Diagonally Upward into Two-Layer Density-Stratified Fluid in a Cylindrical Tank

This study is concerned with the experimental investigation of a jet issuing diagonally upward into a two-layer density-stratified fluid in a cylindrical tank and the resulting mixing phenomena. The upper and lower fluids are water and an aqueous solution of sodium chloride (NaCl), respectively, and the lower fluid issues from a nozzle on the bottom of the tank. The angle between the centerline of the jet and the bottom of the tank is 60o, and the mass concentration of the NaCl solution is 0.02. The investigation reveals that secondary flow is caused by the jet in the horizontal cross-sections of the tank and that it is composed of a pair of vortices. It confirms that the secondary flow at the density interface corresponds to an internal density current. The investigation also clarifies the effect of the Reynolds number of the jet on mixing between the lower and upper fluids.

Precursor ultrasonic effect on grain structure development of AA6061-T6 friction stir weld

Specific locations in horizontal cross-sections of AA6061-T6 weld nuggets, prepared with and without precursor ultrasonic vibrations in friction stir welding, were orientation imaged using electron back scattered diffraction and compared. With ultrasonic vibrations, grains exhibited higher orientation propensity along (101) and (111) and higher grain refinement at middle of weld nugget. Misorientation analysis was conducted using a novel approach where grains with misorientation >45°, <5° and between 15 and 45° were considered as completely recrystallized, under-recrystallized and moderately recrystallized, respectively. The analysis quantitatively showed that higher fractions of completely recrystallized and under-recrystallized grains coexisted in the middle locations where the ultrasonic effect on grain refinement was maximum. A normalized factor revealed that trends of ultrasonic effect on complete recrystallization and grain refinement of nugget are similar, suggesting that ultrasonic induced complete recrystallization is the reason for higher grain refinement. Microtexture was C+B/B− mixture with the C component weakening and B component roughly strengthening down the depth. Microtexture variations are more intensified in the middle locations with ultrasonic vibrations, causing increase in anisotropy, contrary to reported anisotropy loss in transverse locations. Scope of the observed variations in anisotropy and recrystallization towards improvement of process effectiveness and weld mechanical properties are discussed.

Determination of Qualified Spaces at Two-View Autostereoscopic Displays From One-Point Luminance Profile Measurements

We introduce an extended evaluation method to calculate the horizontal cross sections of qualified spaces. The method is based on one-point luminance measurements at the center of autostereoscopic two-view displays. It enables a powerful appraisal of autostereoscopic two-view displays with respect to the ergonomic viewpoint. We show how the freedom of movement for the observer of an autostereoscopic display depends on the interpupillary distance. Thus, individual interpupillary distances are considered to determine the new introduced qualified stereoscopic eye spaces. The evaluation of these spaces results in the quantification of the freedom of movement of the observers in the form of several reference values and charts. The introduced concept of qualified eye spaces is compatible with the current standardization of autostereoscopic displays and overcomes the limitations of the previously discussed concept of qualified viewing spaces.

Aerodynamic Effects of Unsteady Blade-Tower Interaction

In this study, a 2D model as the horizontal cross-sections for HAWT of NREL phase VI is investigated to figure out the flickering of aerodynamic force with six different geometries by pressure-based Navier-Stokes solver and k-ω SST turbulence model. All six cases presented have zero yaw angle and zero pitch angle. Computational domain is divided as sliding mesh and stagnation domains to simulate the blade motion. In this article the dynamic response of tower interference is performed by lateral force, lift force, pressure coefficient and velocity contour by locations of the blade. The aerodynamic response is arranged in an overshoot function for the lift force coefficient of the airfoil to account for the aerodynamic coupling with the tower. This work present in this study gives an insight into rotor structure aerodynamic and aeroelastic interaction.

A study of making a dress form for women using a 3D printer

In the Korean fashion industry, 3D printing systems are considered as new technology and a new opportunity. With 3D printers, consumers can be manufacturers and individuals can develop businesses with little upfront capital. In this study, a dress form for the typical Korean women`s body shape was developed using 3D technology (3D scanning, 3D modeling, and 3D printing). Ten women with apparel sizes 85-91-160 were selected from 3D body-scan data collected by SizeKorea of 201 women aged 25 to 34 (2010). First, 15 horizontal cross-sections were collected from the 3D scan data of the 10 subjects. Then, inside lines of those cross-sections were drawn at 15-degree intervals, and the lengths were measured. The average of the inside lines was connected to the internal spline curve, and the curves were used as the average cross-sections. The average torso body and the dress form of Korean women were developed into a 3D solid model using a 3D CAD program (Solidworks 2012). An output mockup was printed by the FDM type`s 3D printing system (Bonbot 1200, Bonbot 3-H4) using PLA material. The dimensions comparing the 3D solid modeling to the 3D printed mockup of the dress form were measured, and minor differences were between 0.00cm and 0.40cm. In the future, 3D printing systems are expected to be in use for various personalized dress forms.