Vertical Screen Research Articles

Determination of the stiffness of an elastic suspension of a vertical vibratory screen and the characteristic vibrational frequencies of the working organ

Computational relations for determining the stiffness of an elastic suspension of a vertical vibratory screen taking account factors influencing the efficiency of the screen in filtering ceramic suspensions are presented. The vibrational frequency and amplitude which optimize the operation of the screen while maintaining its service life and the serviceability of its design are recommended.

We hunters: interactive communication for young cavemen

This paper presents a multi-user virtual heritage application that allows children to experience and learn the hunting strategies depicted in a cave painting from 6000 BC. The application is based on a multi-touch vertical screen that allows for full-body interaction through carefully defined gestures that search to provide sufficient ecological naturalness and experimentation freedom to the users. This paper gives a detailed account on the experience and interaction design, agent programming and multi-touch technology. It also presents an experimental set-up, especially designed to assess the impact of the installation in the educational goal, the usability of the experience and the results obtained.

Solving vertical and horizontal well hydraulics problems analytically in Cartesian coordinates with vertical and horizontal anisotropies

Summary A new generalized three-dimensional analytical solution is developed for a partially-penetrating vertical rectangular parallelepiped well screen in a confined aquifer by solving the three-dimensional transient ground water flow differential equation in x – y – z Cartesian coordinates system for drawdown by taking into account the three principal hydraulic conductivities ( K x , K y , and K z ) along the x – y – z coordinate directions. The fully penetrating screen case becomes equivalent to the single vertical fracture case of Gringarten and Ramey (1973) . It is shown that the new solution and Gringarten and Ramey solution (1973) match very well. Similarly, it is shown that this new solution for a horizontally tiny fully penetrating parallelepiped rectangular parallelepiped screen case match very well with Theis (1935) solution. Moreover, it is also shown that the horizontally tiny partially-penetrating parallelepiped rectangular well screen case of this new solution match very well with Hantush (1964) solution. This new analytical solution can also cover a partially-penetrating horizontal well by representing its screen interval with vertically tiny rectangular parallelepiped. Also the solution takes into account both the vertical anisotropy ( a zx = K z / K x ) as well as the horizontal anisotropy ( a yx = K y / K x ) and has potential application areas to analyze pumping test drawdown data from partially-penetrating vertical and horizontal wells by representing them as tiny rectangular parallelepiped as well as line sources. The solution has also potential application areas for a partially-penetrating parallelepiped rectangular vertical fracture. With this new solution, the horizontal anisotropy ( a yx = K y / K x ) in addition to the vertical anisotropy ( a zx = K z / K x ) can also be determined using observed drawdown data. Most importantly, with this solution, to the knowledge of the author, it has been shown the first time in the literature that some well-known well hydraulics problems can also be solved in Cartesian coordinates with some additional advantages other than the conventional cylindrical coordinates method.

386 Improved Identification and Visualization of Emergency Department Patient Visits

386 Improved Identification and Visualization of Emergency Department Patient Visits

Comparative study of netbooks and tablet PCs for fostering face-to-face collaborative learning

With the recent appearance of netbooks and low-cost tablet PCs, a study was undertaken to explore their potential in the classroom and determine which of the two device types is more suitable in this setting. A collaborative learning activity based on these devices was implemented in 5 sessions of a graduate engineering course of 20 students, most of whom were aged 22–25 and enrolled in undergraduate computer science and information technology engineering programs. Student behavior attributes indicating oral and gesture-based communication were observed and evaluated. Our findings indicate that in the context in which this study was undertaken, tablet PCs strengthen collective discourse capabilities and facilitate a richer and more natural body language. The students preferred tablet PCs to netbooks and also indicated greater self-confidence in expressing their ideas with the tablet’s digital ink and paper technology than with the netbooks’ traditional vertical screen and keyboard arrangement.

Investigation of Relative Mobile Phone Size Preference Using Interactive Genetic Algorithms

There are 4.6 billion mobile phone subscriptions worldwide, yet relatively little is known about what leads to a highly desirable phone design. This study employed an Interactive Genetic Algorithm (IGA) to identify the relative importance of physical factors in mobile phone design, calculating factor preference ratios and the limits of user discriminability between levels of the factors. Ten participants interacted with a GUI running the IGA to iteratively evolve their preferred design. Screen size, button spacing, and phone radius were varied independently. Results showed that users strongly preferred their final designs over initial ones, validating the use of an IGA in this application. Vertical screen size and button spacing were significantly different between the first and last iterations. A Principal Component Analysis (PCA) showed horizontal screen size preference varied between participants, and vertical screen size and phone radius were correlated. Future research needs are discussed, including testing the effect of prompt on design preference.

Evolution of Cardiopulmonary Bypass

At the end of the Second World War, the devastation of many cities in Europe, combined with the problems of reconstruction and loss of financial support, had brought European medical research to a halt. On the other hand, in the United States the war brought about an enormous amount of scientific research through the development of nuclear weapons, the mass production of penicillin, early computers, and a variety of other technological advances, some of which were eventually put to use by medical investigators. In the immediate postwar years, Congress began 3 decades of generous funding for medical research and education through the National Institutes of Health and the Public Health Service. In the 1920s and 1930s, medical research money had been scarce, but after the war there was a flood of money. The National Institutes of Health budget for medical research in 1945 was $180 000. By 1947, it was increased to $4 000 000, in 1950 to $46 000 000, and in 1974 to $1 billion.1 By 2008, the total budget just for the Heart, Lung, and Blood Institute was almost $3 billion. Since colonial times, it had been customary for young American physicians to spend postgraduate time in Vienna, Berlin, London, or Paris. Now the opposite was true. It became important for a young European physician to have worked for a year or so in a US medical center. The world center for medical education and research had shifted from Europe to the United States. Postwar medical progress was also stimulated by several other programs. The Hill-Burton act of 1946 provided funds for community hospital upgrades and construction. Initially this bill provided $75 million per year for 5 years. It was a matching plan in which local hospitals were required to raise two thirds of the new …

Construction defect management using a telematic digital workbench

Real-time, rich-media data communication between the construction site and the off-site design office is becoming one of the important research areas in information technology for construction. This paper presents the concept of a telematic digital workbench, a horizontal tabletop user interface integrating mobile computing and wireless communication to facilitate synchronous construction site to office collaboration. We demonstrate the capabilities and potentials of this system concept for construction defect management. The on-site crew uses a handheld mobile device to collect defect information and transfers the information to the design office through wireless communication by sending the information to a database listener. The digital workbench application monitors the database and synchronizes the location of the visual information on the site with the 3D model on the server. Integrated with 3D viewing capability in a CAD system, designers can interact with the combined model/site data using a horizontal and vertical screen. A case study compared the telematic digital workbench against paper-based and Pocket PC-based methods for defect management in a controlled laboratory experiment. The case study results show that the telematic digital workbench has the potential to improve the accuracy of matching site data to digital data and reduce information loss between site and office collaboration.

Optical simulation of bistatic specular reflection by a rigid cone on a flat surface.

To gain insight into the high-frequency scattering of sound by cone-shaped objects near flat reflecting surfaces, a small conical mirror was placed on a flat horizontal mirror and illuminated by a tilted laser beam. The symmetry axis of the cone was vertical. Light scattering patterns were recorded by imaging with a camera on a white vertical screen that intersected the scattering. Bright regions on the screen were associated with specular reflections from the cone and from the flat mirror. To determine which contributions depended on the presence of the flat mirror, the screen was also imaged with the cone on a nonreflecting surface. The patterns were recorded with the screen placed sideways relative to the laser beam as well as in front of the cone and behind the cone. The cone half-angle was 45 deg but the grazing angle of the laser beam could be changed. The bright patterns were described by a geometric analysis of bistatic reflection previously summarized [P. Marston, J. Acoust. Soc. Am. 124, 2584 (2008)] modified so as to allow for images caused by the flat mirror. The pattern for a vertical circular cylinder on a mirror was also studied. [Research supported by ONR.]

WAVE ATTENUATION CHARACTERISTICS OF CHAMBERED BREAKWATER

ABSTRACT The reflection characteristics and the dynamic pressures exerted on an impermeable wall on the leeward side of permeable wave screens due to action of regular waves were taken up for investigation through theoretical and experimental programs. The two wave attenuating chambers are formed by placing horizontal slotted wave screens consisting of equally spaced circular wave-intercepting elements. The theoretical model is based on the eigenfunction expansion theory for linear waves, which has been successfully applied earlier for evaluating the hydrodynamic performance of vertical slotted screens by Issacson et al. (1998, 1999) and subsequently for pile supported barriers by Laju et al. (2006). The agreement between theoretical and experimental results is found to be good for the tested range of wave conditions. The present theoretical model is also found to be good in predicting the reflection characteristics of multi-chambered breakwaters. The formulation of theory, solution methodology, details of experiments and the results are discussed in this paper.

VDT Screen Height and Inclination Effects on Visual and Musculoskeletal Discomfort for Chinese Wheelchair Users with Spinal Cord Injuries

This study investigated the visual fatigue and musculoskeletal discomfort for wheelchair users in a VDT data entry task. Eight Chinese male wheelchair users were recruited as participants to perform 9 different experimental combinations. Three screen heights and three screen inclinations were evaluated. Visual fatigue was measured using the change in critical fusion frequency (CFF), near point accommodation (NPA) and a visual complaint questionnaire. Musculoskeletal discomfort was estimated using the rating of perceived exertion (RPE). Each participant performed a data-entry task within a 30 min period using random orders. All participants during the data-entry operation used the upright posture with the participant's lower and upper arms forming right angles. The results showed that the screen height and screen inclination significantly affected visual fatigue and musculoskeletal discomfort. On average, the optimal screen height choice for wheelchair users was at eye-level height or 5 cm below eye level with a vertical screen inclination.

Recognition of hand shape drawings on vertical and horizontal display.

visual recognition of body parts activates somato-motor representations in the brain. In the present study, we investigate the influence of the plane in which hand drawings are displayed (Vertical or Horizontal) on mental rotations evoked by a handedness recognition task. Sixteen right-handed volunteers participated in an experiment where the task was to evaluate the handedness of drawings of the human hand presented in different perspectives and orientations while the Manual Reaction Time (MRT) was measured. For eight volunteers, the hand drawings were displayed on a vertical screen monitor, while for the remainder a mirror was employed and the same drawings appeared on the horizontal plan. Our main finding was that there are no differences in MRTs among the drawings displayed vertically or horizontally, with some exceptions. However, the MRTs were longer when the hands in the drawings assumed configurations that were more awkward to perform using real movements. These results show that the implicit movements involved with handedness recognition are mainly dependent on biomechanical constraints for distal (hand), but not proximal (shoulder) movements. Keywords: handedness recognition, motor imagery, manual reaction time, visual representations, sensorimotor representations.

Traffic Noise Sources in Cutting Dips Adjacent to Screens

The use of a single vertical screen to obstruct the propagation of noise from source to receiver over hard and soft flat ground is well known. However, in addition to considerations of acoustical efficiency, the design of road traffic noise barriers depends on many other factors. Site conditions, planning restraints and visual considerations will affect the final selected design, as will engineering considerations related to the construction materials, the weather loading due to wind and precipitation. The aim of this article is to show both the acoustical benefits and drawbacks of using a screen adjacent to a highway located in a cutting dip in otherwise flat ground topography.

Multidirectional UV Lithography for Complex 3-D MEMS Structures

Various three-dimensionally (3-D) complex MEMS structures are fabricated using multidirectional ultraviolet (UV) lithography, which includes reverse-side exposure through a UV-transparent substrate, inclined exposure with or without simultaneous substrate rotation, and the combination of these processes. A reverse-side exposure scheme through UV-transparent substrates (e.g., glass, sapphire, or quartz) has been exploited for implementing high-aspect-ratio structures (greater than 20:1), repeatable self-alignment photoresist patterning with subsequent metallization on a BST/sapphire substrate, and unconventional patterning using substrate optics such as proximity patterning or integrated lens techniques. Inclined exposure has been applied to a SU-8 substrate with differing inclination angles and incidence directions. The refractive index of SU-8 is experimentally determined to be 1.68 by means of test structures fabricated using this approach. Implemented structures using the inclined exposure include vertical screen structures, inclined tubes, and conical shape structures. Dynamic mode operation, in which the substrate is continuously rotated and tilted during exposure is also discussed. Examples of achievable 3-D structures using dynamic mode operation are presented.1581

A simple method to predict flow distribution at vertical angled screens in open channels

This paper presents a simple method to predict flow diversion by vertical angled screens in open channels. The performance of this method has been compared with the experimental results from a recent laboratory study of vertical angled screens. This method is then used to predict the effect of screen porosity, variation of porosity along the length of the screen, and several other factors on the flow division. The results of this investigation would be useful in the design of vertical angled screens for fish protection at water intakes from rivers for irrigation, and other industrial uses.Key words: fish screens, intakes, water flow, irrigation canals, open channel flow, hydraulics and fish diversion.

On the efficiency of screens near roadside cuttings

The prediction of acoustic propagation from a monofrequency coherent line source in a cutting with impedance boundary conditions over a noise-screen onto surrounding flat grassland is presented. It is well known that over flat ground the spectra for single-noise screens have significant marked differences for propagation over absorbing ground where the screen obstructs surface wave attenuation over the absorbing ground cover. The aim here is to extend the study of this phenomenon for screens adjacent to cuttings or dips surrounded by absorbing ground. The study is based on a numerical model using boundary element techniques that enables the excess attenuation and insertion loss for various noise barriers and cuttings of complex profile and surface cover to be calculated. The model is applied to single-foundation noise barriers to which additional absorbent or rigid side-panels are added to create profiles and a double-barrier configuration is also studied. Spectra of insertion loss, change in insertion loss and excess attenuation results for a broadband traffic-source are presented. It is concluded that “multiple-edged” barriers only show a minor increase in acoustic efficiency over simple vertical screens for a noise source located in perturbed flat ground conditions such as a cutting; in addition it is shown that a screen placed close to the source shows sign of partial improvement.

The architecture of New Zealand's divaricate shrubs in relation to light adaptation

The divaricating shoot habit is typified by a suite of architectural traits, quantified here using phylogenetic independent comparisons of three pairs of congeners, with or without the habit. We consider the hypothesis that the habit evolved as a structural photoprotection mechanism that maximises potential carbon fixation by minimising photoinhibition. Plants were grown in pots in full sun, or behind vertical screens transmitting c. 25, 52, or 73% sunlight. When shaded, all species shifted partitioning of biomass from stem thickening to leaf area expansion and occupied a larger crown volume for a given shoot biomass. Leaf numbers per stem length of divaricates and non‐divaricates were greater in the lower and upper canopies, respectively, consistent with the view that in divaricates outer branches protect inner leaves. However, leaf numbers per stem length showed no response to variation in high light receipt. Divaricates showed some traits typical of plants adapted to sunny habitats: smaller effective leaf size, lesser fractional partitioning of biomass to leaves, and greater foliage densities. Other traits of divaricates were typical of plants adapted to shaded habitats: lesser stem diameters, stem biomass per unit stem length, leader dominance, leaf area index, nd heights relative to crown diameters; and more horizontal twig orientations. Compensation for high costs of support of photosynthetic area in divaricates (leaf area per unit shoot biomass c. 1.3 m2kg‐1) compared with non‐divaricates (c. 5.5 m2kg‐1) would require a larger enhancement of net canopy photosynthesis than is likely to arise from avoidance of photoinhibition.

Movement planning of video and of manual aiming movements

We studied aiming performance of adults for video- and manual aiming tasks when they had visual information about the location of the starting base or when they had not. In video-aiming, foveating the starting base and then the target prior to movement initiation (Foveation) resulted in less aiming bias and variability than when the starting base was not visible (PNV), or visible without the participants foveating it prior to movement initiation (PSV). In manual aiming, Foveation and PSV procedures resulted in identical results but reduced aiming bias and variability in comparison to the PNV procedures. The results indicate that participants had difficulty in transforming the locations of the starting base and of the target when seen on a vertical screen into an appropriate movement trajectory. Successive foveation of the starting base and of the target facilitated this transformation, resulting in direction variability being reduced by more than half in comparison to the PNV and PSV conditions. This suggests that in video-aiming the efference copy of the saccade can be used by the CNS to approximate the hand trajectory in the workspace and/or in joint coordinates (Jouffrais and Boussaoud, 1999). Hand trajectory could be readily available in manual aiming if the target location can be recoded directly in hand-coordinates as recently suggested by Buneo et al. (2002).

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Visual feedback reduces bimanual coupling of movement amplitudes, but not of directions

To what extent does visual feedback shape the coordination between our arms? As a first step towards answering this question, this study compares bimanual coupling in simultaneous bimanual reversal movements that control cursor movements on a vertical screen. While both cursors were visible in the control condition, visual feedback was prevented in the experimental condition by deleting one or both cursors from the screen. Absence of visual feedback for one or both arms significantly increased the reaction times of both arms and the movement amplitude of the occluded arm. Temporal coupling between the arms remained unchanged in all feedback conditions. The same was true for spatial coupling of movement directions. Amplitude coupling, however, was significantly affected by visual feedback. When no feedback for either arm was available, amplitude correlations were significantly higher than when feedback for one or both arms was present. This finding suggests that online visual feedback decreases bimanual amplitude coupling, presumably through independent movement corrections for the two arms. The difference between movement amplitudes and movement directions in their susceptibility to visual feedback supports the idea that they are subserved by different control mechanisms. Analysis of eye movements during task performance revealed no major differences between the different feedback conditions. The eye movements of all subjects followed a stereotypical pattern, with generally only one saccade after target onset, directed towards the average position of all possible targets, irrespective of feedback condition and target direction.