Initial Design (initial + design)

Distribution by Scientific Domains


Selected Abstracts


An air filter pressure loss model for fan energy calculation in air handling units

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2003
Mingsheng Liu
Abstract Air filters consume a significant part of the fan power in air handling systems. Due to lack of suitable models, the fan energy associated with the filter pressure drop is often estimated based on average airflow and average pressure drop across the filter. Since the pressure drop varies nonlinearly with airflow and the filter resistance varies with dirt build-up, current methods often produce erroneous results. This paper presents a new air filter pressure loss model that has been developed and verified using experimental data. The model projects the pressure losses across the filter for both constant and variable airflows. The inputs to the model are the airflow rate, the time of use, the initial design and final pressure losses at the design flow rate, and the coefficient of a power law regression of pressure loss as a function of airflow rate. The air filter pressure loss model may be implemented in hourly building energy simulation programs that perform hourly simulation at the air handling unit level. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Using dendronal signatures for feature extraction and retrieval

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2000
Luojian Chen
A dendrone is a hierarchical thresholding structure that can be automatically generated from a complex image. The dendrone structure captures the connectedness of objects and subobjects during successive brightness thresholding. Based on connectedness and changes in intensity contours, dendronic representations of objects in images capture the coarse-to-fine unfolding of finer and finer detail, creating a unique signature for target objects that is invariant to lighting, scale, and placement of the object within the image. Subdendrones within the hierarchy are recognizable as objects within the picture. Complex composite images can be autonomously analyzed to determine if they contain the unique dendronic signatures of particular target objects of interest. In this paper, we describe the initial design of the dendronic image characterization environment (DICE) for the generation of dendronic signatures from complex multiband remote imagery. By comparing subdendrones within an image to dendronic signatures of target objects of interest, DICE can be used to match/retrieve target features from a library of composite images. The DICE framework can organize and support a number of alternative object recognition and comparison techniques, depending on the application domain. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 243,253, 2000 [source]


Dynamic performance of the beam position monitor support at the SSRF

JOURNAL OF SYNCHROTRON RADIATION, Issue 1 2009
Xiao Wang
Electron beam stability is very important for third-generation light sources, especially for the Shanghai Synchrotron Radiation Facility whose ground vibrations are much larger than those for other light sources. Beam position monitors (BPMs), used to monitor the position of the electron beam, require a greater stability than other mechanical structures. This paper concentrates on an investigation of the dynamic performance of the BPM support prototype. Modal and response analyses have been carried out by finite-element (FE) calculations and vibration measurements. Inconsistent results between calculation and measurement have motivated a change in the soft connections between the support and the ground from a ground bolt in the initial design to full grout. As a result the mechanical stability of the BPM support is greatly improved, showing an increase in the first eigenfrequency from 20.2,Hz to 50.2,Hz and a decrease in the ratio of the root-mean-square displacement (4,50,Hz) between the ground and the top of the support from 4.36 to 1.23 in the lateral direction. An example is given to show how FE analysis can guide the mechanical design and dynamic measurements (i.e. it is not just used as a verification method). Similar ideas can be applied to improve the stability of other mechanical structures. [source]


Micromachined CMOS E-band bandpass coplanar filters

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008
Pen-Li Huang
Abstract In this work, E-band CMOS coplanar filters, whose initial design is made according to quasi- TEM-approximation-based analytical models, are implemented. To study the substrate effects, the CMOS-compatible inductively coupled-plasma (ICP) deep trench technology is used to selectively remove the silicon underneath the filter completely. For the filter with top metal thickness of 0.93 ,m after the backside ICP etching, the results show that the input matching bandwidth, i.e. S11 below ,10 dB, moves from lower 39.8,81.4 GHz-band to higher 55.9,94.1 GHz-band, and the 3-dB bandwidth of S21 moves from lower 43.5,76.3 GHz-band to higher 54.5,93.3 GHz-band. In addition, a 4.67 dB improvement [from ,8.86 dB (at 58.5 GHz) to ,4.19 dB (at 74.5 GHz)] in peak S21 was achieved. These results show that for the design of passive coplanar devices in the E-band, the quasi-TEM- approximation-based analytical models can be used and the backside ICP etching is effective to reduce the substrate loss and parasitic capacitance. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3123,3125, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23873 [source]


A survey in the park: Methodological and practical problems associated with geophysical investigation in a late Victorian municipal park

ARCHAEOLOGICAL PROSPECTION, Issue 3 2010
Andrew Parkyn
Abstract The survey of Pudsey Park is a geophysical investigation of a late Victorian municipal park. The aim of the survey was to use geophysical techniques to identify the park's changing designs over a 120 year period. An initial design for the park was located during the desk-based assessment, however, it was unclear how much of the original plan had been implemented. It was suspected that Pudsey Park's design has been simplified over time. The project also aimed to identify a suitable sampling strategy for studying park and garden sites by using high-resolution surveys and multiple probe separations for varying depths of detection during earth resistance survey. It was hoped that multiple electrode separations combined with a high density survey could be used to differentiate the signal responses from the modern park designs and earlier design schemes. The choice of strategy is at a significantly higher resolution than guidelines for geophysical investigations for traditional archaeological features. The survey provided highly detailed but complicated data sets; areas of the park have had several redesigns, often where the modern scheme masks previous designs. A number of ,hard' and ,soft' landscaping features were identified including the foundations of the original bandstand (now replaced) and former flower beds. The 0.25,m probe separation surprisingly produced the most defined data with the greatest level of information due to the increased spatial resolution. The geophysical investigation is the first of its kind to investigate a Victorian municipal park in its entirety. The survey validates the importance of high-resolution survey in the study of parks and gardens and also provides a reference data set for future work where poorer documentation hinders interpretation. The geophysics data, together with the accompanying Geographical Information System database produce a unique and detailed picture of a Victorian park from its inception through 120 years of development. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Disposable MagLev Centrifugal Blood Pump Utilizing a Cone-Shaped Impeller

ARTIFICIAL ORGANS, Issue 8 2010
Wataru Hijikata
Abstract To enhance the durability and reduce the blood trauma of a conventional blood pump with a cone-shaped impeller, a magnetically levitated (MagLev) technology has been applied to the BioPump BPX-80 (Medtronic Biomedicus, Inc., Minneapolis, MN, USA), whose impeller is supported by a mechanical bearing. The MagLev BioPump (MagLev BP), which we have developed, has a cone-shaped impeller, the same as that used in the BPX-80. The suspension and driving system, which is comprised of two degrees of freedom, radial-controlled magnetic bearing, and a simply structured magnetic coupling, eliminates any physical contact between the impeller and the housing. To reduce both oscillation of the impeller and current in the coils, the magnetic bearing system utilizes repetitive and zero-power compensators. In this article, we present the design of the MagLev mechanism, measure the levitational accuracy of the impeller and pressure-flow curves (head-quantity [HQ] characteristics), and describe in vitro experiments designed to measure hemolysis. For the flow-induced hemolysis of the initial design to be reduced, the blood damage index was estimated by using computational fluid dynamics (CFD) analysis. Stable rotation of the impeller in a prototype MagLev BP from 0 to 2750 rpm was obtained, yielding a flow rate of 5 L/min against a head pressure in excess of 250 mm Hg. Because the impeller of the prototype MagLev BP is levitated without contact, the normalized index of hemolysis was 10% less than the equivalent value with the BPX-80. The results of the CFD analysis showed that the shape of the outlet and the width of the fluid clearances have a large effect on blood damage. The prototype MagLev BP satisfied the required HQ characteristics (5 L/min, 250 mm Hg) for extracorporeal circulation support with stable levitation of the impeller and showed an acceptable level of hemolysis. The simulation results of the CFD analysis indicated the possibility of further reducing the blood damage of the prototype MagLev BP. [source]