Dimensional Extent Research Articles

A Numerical Study on the Impact of Building Dimensions on Airflow Patterns and Bed Morphology around Buildings at the Beach

The attractiveness of beaches to people has led, in many places, to the construction of buildings at the beach–dune interface. Buildings change the local airflow patterns which, in turn, alter the sediment transport pathways and magnitudes. This induces erosion and deposition patterns around the structures. In this study, a numerical model is developed using the open-source computational fluid dynamics solver OpenFOAM. First, the model is used to predict the airflow patterns around a single rectangular building. The model predictions are validated with wind-tunnel data, which show good agreements. Second, a reference beach building is introduced and then the building dimensions are increased in length, width and height, each up to three times the reference building dimension. The impact of each dimensional extent on the near-surface airflow patterns is investigated. The results show that the near-surface airflow patterns are least dependent on the length of the building in the wind direction and they depend most on the width of the building perpendicular to the wind direction. Third, the convergence of the third-order horizontal near-surface velocity field is calculated to interpret the impact of changes in airflow patterns on potential erosion and deposition patterns around the building. The numerical predictions are compared with the observed erosion and sedimentation patterns around scale models in the field. The comparisons show satisfactory agreements between numerical results and field measurements.

MEA Viewer: A high-performance interactive application for visualizing electrophysiological data.

Action potentials can be recorded extracellularly from hundreds of neurons simultaneously with multi-electrode arrays. These can typically have as many as 120 or more electrodes. The brief duration of action potentials requires a high sampling frequency to reliably capture each waveform. The resulting raw data files are therefore large and difficult to visualize with traditional plotting tools. Common approaches to deal with the difficulties of data display, such as extracting spike times and performing spike train analysis, are useful in many contexts but they also significantly reduce data dimensionality. The use of tools which minimize data processing enable the development of heuristic perspective of experimental results. Here we introduce MEA Viewer, a high-performance open source application for the direct visualization of multi-channel electrophysiological data. MEA Viewer includes several high-performance visualizations, including an easily navigable overview of recorded extracellular action potentials from all data channels overlaid with spike timestamp data and an interactive raster plot. MEA Viewer can also display the two dimensional extent of action potential propagation in single neurons by signal averaging extracellular action potentials (eAPs) from single neurons detected on multiple electrodes. This view extracts and displays eAP timing information and eAP waveforms that are otherwise below the spike detection threshold. This entirely new method of using MEAs opens up novel research applications for medium density arrays. MEA Viewer is licensed under the General Public License version 3, GPLv3, and is available at http://github.com/dbridges/mea-tools.

Identification of damage mechanisms in cement paste based on acoustic emission

Acoustic emission (AE) monitoring during compressive loading was employed to investigate micro-crack formation and coalescence in cement paste specimens. To establish a correlation between damage and AE activity, the data was categorized on the basis of amplitude and cumulative signal strength (CSS). Three distinct stages of crack behavior, illuminated by changes in the slope of the cumulative signal strength versus time relationship, were identified. Micro-crack initiation, crack extension, and unstable crack growth (crack coalescence) were assigned to these stages. An unsupervised pattern recognition approach was employed to separate the data into signal subsets which were then classified and assigned to differing mechanisms. To gain further insight into the crack growth network and behavior, specimens were loaded to varying levels of ultimate capacity and micro-CT scanning was employed to investigate the dimensional extent of micro-cracking and to correlate the images with AE data.

Space in Lisu

Author(s): Bradley, David | Abstract: Space is categorized and expressed in Lisu in all areas of structure, both nominal and verbal. Within the nominal system, there is a complex deictic system which differs between dialects and which has distinct fused locative forms, as well as a large set of spatial frame nominals, some derived from body parts, as well as directional suffixes and a spatial marker suffix; the ways in which these suffixes combine with nouns and noun stems differ slightly between dialects. There are also some general nouns for location in space and a spatial numeral classifier. Some of these nominal spatial forms are metaphorically extended to temporal, comparative and more lexicalized uses. Within the verbal system, directions of motion and types of location are expressed by lexically distinct verbs. As in most Ngwi languages related to Lisu, there is a morphosyntactically distinct set of dimensional extent stative verbs expressing spatial extension as well as temporal extent. There is also a set of posthead directional serial verbs. Finally, there are spatial adverbial forms productively based on the dimensional extent verbs.

Kaon femtoscopy in =200 GeV central Au+Au collsions at STAR

Three-dimensional analyses of the pion source revealed a heavy, non-Gaussian tail in the direction of the pair transverse momentum. The interpretation of these pion sources in terms of pure hydrodynamical evolution is, however, complicated by the strong contribution of feed-down from long-lived resonances to the source. On the other hand, kaons provide a much cleaner probe of the expanding fireball. Here we present a recent three-dimensional kaon correlation analysis using Cartesian harmonics decomposition technique. In contrary to pions, the three-dimensional source function of kaons is largely Gaussian. Comparison with thermal simulations and a hydrokinetic model show that resonance decays, as well as non-zero emission duration and/or rescattering in the hadronic phase play an important role. The analysis of the three dimensional extent of the kaon source w.r.t. the pair transverse momentum favors the hydrokinetic model over the exact mi-scaling featured by perfect hydrodynamical models.

Structure–wear-property correlation

Wear is the loss of dimension through plastic deformation, which originates at interfaces between two sliding surfaces. Hence, it is logical to correlate the worn surface features and their morphologies with the resulting wear properties. The two dimensional extent of such wear damage accumulations (i.e., impressions of ploughing lines along with adhered debris fraction), quantified from the worn surface fractographs are observed to predict the nature of the variation in the wear properties with various loading conditions, for different grades of magnesium alloys at ambient temperature. Microstructural investigation of the worn surfaces and the wear debris have been carried out to explain the observed results and to understand the wear micro-mechanisms of different magnesium alloys under various loading conditions. In the present study, a new technique has been employed to measure the extents of ploughing lines impressions with adhered debris formation on the worn surface fractographs off-line under image processing platform.

Mining Sand on the Continental Shelf of the Atlantic and Gulf Coasts of the U.S.

Essentially all marine mining along the East and Gulf coasts of the U.S. is for sand used in beach nourishment projects. The current minimal commercial production of sand and aggregate may increase as conventional, on-shore sources become exhausted or are lost to competing land use. Studies published in the late 1990s document a history of nearly 900 individual episodes of beach nourishment having a total cost in excess of $2 × 109 with several hundred million cubic meters of sand placed along over 645 km (400 mi) of shoreline. As exemplified by studies in Florida, prospecting for sand for use in beach nourishment can begin before site specific needs are identified. A full prospecting starts with assimilation of pertinent literature, local knowledge, and an understanding of the geologic and geomorphic settings in which suitable deposits of sand or aggregate occur. High-resolution seismic profiling follows to outline the three dimensional extent of the sand bodies. Finally, vibratory cores are collected to verify the interpretation of the seismic data and to provide samples for geotechnical, especially granulometric, analyses. The actual method of production often is determined by the local availability of different dredge types. Because the mining of marine sands disturbs meaningful areas of the sea floor, environmental concerns must be considered. While it generally is assumed that dredged areas will be left barren, it is possible to assess the likely rate of recolonization. The disruption of bottom habitat also can affect feeding and spawning areas for fishes and other organisms. Alteration in local currents and wave transformation processes need to be modeled and their consequences assessed.

Thermodynamics of free domain wall fermions

Studying various thermodynamic quantities for the free domain wall fermions for both finite and infinite fifth dimensional extent ${N}_{5}$, we find that the lattice corrections are minimal for ${N}_{T}\ensuremath{\ge}10$ for both energy density and susceptibility, for its irrelevant parameter $M$ in the range 1.45--1.50. The correction terms are, however, quite large for small lattice sizes of ${N}_{T}\ensuremath{\le}8$. We propose modifications of the domain wall operator, as well as the overlap operator, to reduce the finite cutoff effects to within 10% of the continuum results of the thermodynamic quantities for the currently used ${N}_{T}=6--8$ lattices. Incorporating the chemical potential, we show that divergences proportional to ${\ensuremath{\mu}}^{2}/{a}^{2}$ are absent for a large class of such domain wall fermion actions although the chiral symmetry is broken for $\ensuremath{\mu}\ensuremath{\ne}0$ at any finite lattice spacing.

3차원 비선형 동적해석을 이용한 입체라멘교의 지진거동특성에 관한 연구

비선형동적해석을 통하여 RC 입체라멘교에 대한 지진거동특성 및 파괴메카니즘에 관한 연구를 수행하였다. 파이버모델에 기초한 RC 프레임요소를 교각에 도입하여 3차원영역에서 모델링하여 비선형동적해석을 수행하였다. 해석의 정확성을 향상시키기 위하여 균열 진전후 콘크리트와 철근의 부작특성에 의한 재료역학적 특성차이를 고려하기 위하여 파이버는 철근영역(RC zone)과 무근영역(PC zone)으로 영역화하였다. 대상교량은 관성력 중심위치와 교량의 강성중심 위치가 일치하지 않아 비틀림을 동반한 복잡한 지진거동특성을 나타내었다. 이러한 거동특성에 의하여 유연한 교각 옆에 위치하는 상대적 강성이 큰 교각에 과다한 지진하중이 집중되어 파괴에 이르는 것으로 나타났다. The characteristics of nonlinear seismic behavior and failure mechanism of RC space frame in railroad viaducts have been studied by the numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and the RC frame elements consisting of fibers are employed for the columns. The fibers are characterized as RC zone and PC one to distinguish the different energy release after cracking resulted from the bond characteristic between concrete and re-bar. Due to the deviation of the mass center and the stiffness center of the entire structure the complex behavior is shown under seismic actions. The excessive shear force is concentrated on the column beside flexible one relatively, which leads to the failure of bridge concerned.

Domain wall fermions with exact chiral symmetry

We show how the standard domain wall action can be simply modified to allow arbitrarily exact chiral symmetry at finite fifth dimensional extent. We note that the method can be used for both quenched and dynamical calculations. We test the method using smooth and thermalized gauge field configurations. We also make comparisons of the performance (cost) of the domain wall operator for spectroscopy compared to other methods such as the overlap-Dirac operator and find both methods are comparable in cost.

Exact chiral symmetry for domain wall fermions with finite Ls

We show how the standard domain wall action can be simply modified to allow arbitrarily exact chiral symmetry at finite fifth dimensional extent L s . We note that the method can be used for both quenched and dynamical calculations. We test the method using smooth and thermalized gauge field configurations. We also make comparisons of the performance (cost) of the domain wall operator for spectroscopy compared to other methods such as the overlap-Dirac operator and find both methods are comparable in cost.

Programming in Three Dimensions

Cube is a three-dimensional, visual, statically typed, higher-order logic programming language, designed to be used in a virtual-reality-based programming environment. In this paper, we give an informal overview of the language and describe a prototype implementation.

Monitoring of rice crop growth from space using the ERS-1 C-band SAR

This communication presents preliminary results of the first attempt to monitor rice crop growth from space from transplanting to harvesting with an active microwave instrument using ERS-1 C-band SAR. The variation of /spl sigma//sup 0/ for a test rice field in the Akita Prefectural College of Agriculture obtained from multitemporal SAR data is evaluated by comparing with ground truth data of the rice crop condition. The feasibility is shown of estimating the number of days after transplanting and hence the rice crop growth stage from the /spl sigma//sup 0/ measurement. Correlation analysis suggests a close relationship between /spl sigma//sup 0/ and the two dimensional extent of the rice crops. >

Detecting change in grasslands using measures of spatial dependence with landsat TM data

Spatial dependence is a fundamental structure of spatial data that can be readily measured. Change in landscapes can be monitored effectively using measures of spatial dependence. Scale of fluctuation analysis estimates the dimensional extent to which data are significantly autocorrelated by observing the behavior of sample variance under extended local averaging. Algorithms to estimate the one-dimensional scale of fluctuation (correlation length) and two-dimensional scale fluctuation (correlation area) in image data are described. The approach is demonstrated with an analysis of a 9-year TM image series of a tallgrass prairie preserve, Konza Prairie Research Natural Area, to assess the impact of bison on the spatial patterning of vegetation.

Solder joint reliability of fine pitch surface mount technology assemblies : John Lau, Laura M. Powers-Maloney, James R. Baker, Don Rice and Bob Shaw. IEEE Trans. Compon. Hybrids mfg Technol.13(3), 534 (1990)

GaAs MESFET (chip&wire and flip-chip) and PHEMT devices were plastic-packaged using CVD diamond (CVDD) in SOIC and QFP geometries, respectively. The compatibility of CVDD insertion was considered with respect to thermal, thermo-mechanical, and chemical properties as well as spatial arrangement and dimensional extent of the materials comprising the package structure. Predictive finite element modeling showed optimum thermal and thermo-mechanical designs (minimum thermal resistance, Rth, for the dominant thermal path; minimum principal stress, S1, in the GaAs) to consist of (1), a leadframe-substrate (CVDD) ‘overlap’ configuration, (2), an all-metallic assembly process (die attach + leadframe attach) and (3), a ‘compliant’ metal interlayer between GaAs and CVDD. Additionally, oxidative chemical treatment of the CVDD surface provided a strong affinity between the polymer encapsulant and CVDD, resisting over 50 cycles of 15 min boiling water immersion and peel-adhesion tests before exceeding the criterion for failure. Employing these considerations in the fabrication of CVDD-enhanced GaAs plastic packages provided for significant improvements over the conventional package design with a Cu leadframe substrate. The GaAs/CVDD plastic package performance milestones were: (a) greater than 50% reductions in Θj relative to the Cu die-paddle package (Θj chip&wire = 127°C and Θj flip-chip = 141°C for 2.5 W, 1 GHz, GaAs MESFET; (b) 20 W continuous operation for 96 h with Θj chip&wire = 140°C for a 30 W, 3–6 GHz, GaAs PHEMT; (c) passed MIL STD 883 1000 cycle, −55 to 125°C temperature exposure; (d) passed highly accelerated stress testing, HAST, (110°C, 200 h, 85% RH, 3.1 atm). Electrical performance testing (S-parameter) on metallized CVDD coplanar transmission lines and diamond-enhanced, coplanar GaAs flip-chip MESFET packages showed: (a), transmission line performance equivalent to Al2O3 (<1.5 dB at 20 GHz, VSWR = 1.2 : 1) and (b), near identical performance of devices (no package) and diamond-enhanced, plastic encapsulated packages. These results illustrate that diamond can be processed/packaged using conventional electronics manufacturing techniques and provide superior performance with high reliability for plastic packages.

Non-metallic crystals undergoing cumulative work-hardening and wear due to softer lubricated metal sliding surfaces

A purely mechanical mechanism of the room-temperature wear of hard non-metallic crystals, when traversed by considerably softer lubricated metal cones, has been observed. The contact pressure transmitted to the crystal is directly related to the flow stress of the slider and is therefore dependent on the metal used. It is shown that when this pressure is above a certain threshold level, i. e. just enough to exceed the critical resolved shear stress within the crystal, then dislocations move and multiply in the hard solid. The full dimensional extent of this movement, the dislocated volume, is essentially developed on the first load cycle and is determined in a given crystal primarily by the magnitude of the applied load. Repeated traversals increase the density of defects in this dislocated volume and produce significant work-hardening. The level of work-hardening saturates within comparatively few traversals (typically about twenty) and the degree of work-hardening is limited by the ultimate hardness of the slider ( H u ), or is curtailed by the onset of fracture. A linear relation between H u , varied by using sliders of different metals, and the subsequent hardness of the work-hardened surface ( H t ) is observed for the (001) surfaces of crystals of magnesium oxide, nickel oxide and titanium carbide. The flow stress of the softest metal to induce work-hardening may be used to estimate the critical resolved shear stress of the hard crystal, as shown here for titanium carbide. Further traversals, beyond those necessary to develop a saturation level of work-hardening, generally lead to the formation of surface cracks and catastrophic fragmentation. The number of traversals ( N c ) required to cause this surface fragmentation and accelerated wear is inversely related to the ultimate hardness of the slider, is independent of the normal load, but is dependent on the crystallographic plane and direction of sliding. A plot of H u : N c resembles a conventional fatigue curve and indicates that the surface will not fail when deformed by sliders below a certain limiting value of H u . The cracks that initiate final failure are shown to be generated at the surface, while subsurface cracks, lying on crystallographic planes parallel to the surface, may be formed during initial traversals well before N c . The wear resistance of nickel oxide is superior to that of MgO, although NiO is softer than MgO. Finally, the mechanism of work-hardening is discussed in terms of the interaction of dislocations on obliquely intersecting slip planes, as in conventional stage II work-hardening. The localized stress concentration around the dislocation debris produced by these interactions, in the near-surface layers, is considered to be responsible for the initiation of the cracks that precipitate fragmentation.

ESTUDO DAS CONDIÇÕES HIDROGEOLÓGICAS E HIDROQUÍMICAS DOS AQÜÍFEROS DA REGIÃO DE BIRITINGA - PATAÍBA (BA) UTILIZANDO MÉTODOS GEOFÍSICOS ELÉTRICOS

Drill holes which tapped the aquifers of the Ilhas and Massacara Groups in many places of the Tucano Sedimentary Basin produce water with a high content of dissolved salts. In order to optimize a procedure to determine the two dimensional extent of the salt water occurrence, as well as to contribute to the understanding of possible mechanisms responsible for this salinization, geophysical studies were made in the Biritinga-Paraiba area in the State of Bahia. Twenty eight (28) vertical electrical soundings, electrical logs of 13 wells and chemical analysis of 35 samples of groundwater allowed to determine the structural configuration of the Ilhas-Massacara aquifer system in the region, and to estimate the influence of this configuration on the chemical characteristics of the groundwater. In the study region the system consists of a vertical sequence of sandstone and shale layers dipping SE, which are longitudinally sectioned by gravity faults in a sequence of horsts and grabens. In the horsts where the system contains a high shale-sandstone proportion, the water is more salty. Furthermore, some of the structural blocks have shown an increase of water salinity with depth. These facts seem to indicate that ionic filtering by the shales in the system and a process of mixing and hydrodynamic dispersion along the faults are the main controllers of the characteristics of the groundwater. The results also indicate that under favorable conditions, information about the block structure system and water characteristics can be inferred from surface electrical soundings.

A suppressive effect of rarefied gas flow through a circular orifice caused by temperature increase of the orifice plate (The unsteady approach and the direct Monte-Carlo simulation)

A suppressive effect of rarefied gas flow through a circular office caused by temperature increase of the orifice plate has been investigated experimentally using the unsteady approach. Also numerical analysis has been carried out using the direct simulation Monte-Carlo method. Flow rate decreases as the temperature of the orifice plate increases, in proportion to a square root of the ratio between gas temperature and the plate temperature. In spite of the finiteness of the simulation space due to the three dimensional extent of the space, the simulation results are in good agreement with the experimental results. The suppressive effect of gas Flow is found appreciably even in the small plate of which high temperature area is several times as large as a cross-sectional area of its aperture.

銅単結晶の引っかき変形における加工硬化機構

To clarify the formation mechanism of work-hardened surface layer introduced at the time of abrasive working, (001) single crystal surfaces of Cu were scratched with diamond cone styluses, and the examinations were made around the end of scratch-grooves and also around the cross and vertical-sections of grooves by means of X-ray microbeam technique, TEM, etching and micro-hardness measurements. It was found that the three dimensional extent of deformed region around the groove varies with the scratch direction. And from the analysis of Laue asterisms on X-ray diffraction patterns, the distribution of the activated slip systems contributing to the scratch deformation was estimated. The explanation was made about the work-hardening process around the groove considering the interactions of each slip deformation processes. The dislocation structure near the surface of groove end shows the corresponding variation to the deformation processes, and besides, the anisotropy of hardness distribution beneath the groove can be explained from the difference of the deformation processes.

Cancer of the Nose: Ablation and Repair

Cancer of the nose is very common and lesions seen by reconstructive surgeons are often recurrent and extensive. Surgical removal of cancer of the nasal skin can usually be accomplished under local anesthesia, and in most instances frozen section histologic examination should be used to confirm the adequacy of excision. The location and three dimensional extent of the tumor will dictate the choices of repair or reconstruction as well as the timing thereof. Very small lesions can be excised with primary closure; other well circumscribed tumors can be excised and the defect closed with an appropriate nasal flap. In our experience most nasal skin cancers have been managed by excision and full-thickness skin grafting. We have found the skin of the neck and that of the preauricular region to provide the best skin cover except in the upper third of the nose where upper eyelid skin provides excellent coverage. We have used composite grafts from the ear to replace up to two-thirds of an alar rim. Nasolabial, cheek, and midline forehead flaps are useful in a variety of instances, but usually when less than one-half of the nose has been excised. We have been pleased, in most instances, with the Converse scalping flap for near total, subtotal, and extensive three-dimensional lower nasal defects. (Transverse superficial temporal artery pedicle flaps can be successfully used to reconstruct large nasal defects with adjacent cheek loss.) We have rarely used distant flaps. Regardless of what regional pedicle flap has been transferred to the nose, subsequent revisions of a relatively minor nature will nearly always enhance the result. Patients who have undergone extended total nasectomies are probably best managed with a prosthesis, as prognosis is often guarded and flap reconstruction may be quite unsatisfactory. In our experience, defects in lining and support can usually be repaired with local nasal tissue.