Compact Housing Research Articles

Design and Construction of a 38 T Resistive Magnet at the Nijmegen High Field Magnet Laboratory

The Nijmegen High Field Magnet Laboratory (Nijmegen HFML) presently offers to its users 33 T in two 32 mm bore resistive magnets, 32 T in a 50 mm bore resistive magnet and 30 T in a 50 mm bore hybrid magnet. To comply with the users' demand for ever higher magnetic fields without having to resort to hybrid magnets, a new resistive 20+ MW magnet has been designed and is now being constructed, which will deliver 38 T in a 32 mm bore. The magnet consists of five Florida-Bitter coils and one outer Bitter coil. The two innermost coils ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm A}_{1}$</tex> </formula> and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm A}_{2}$</tex> </formula> , CuAg conductor) are electrically in parallel. The outer coil (E, Cu conductor) has an outer diameter set to 1 m. The length of this coil is about 670 mm and it weighs almost 3000 kg, indicative of the huge amount of conductor material needed for 40 T class resistive magnets. An important issue is the necessity to reduce the slit factor, i.e. the locally high current density in a winding at a slit in a Bitter disk. We therefore decided to implement the modified Weggel stacking scheme for the A, B and C coils, implying a noninteger number of disks per turn, e.g. 11 13/25 for the B coil. Also, a new compact (1.3 m outer diameter, 1.4 m height) housing has been designed, able to withstand the combined stress due to the maximum fault force of 2.1 MN (occurring when the C coil fails) and the effect of 40 bar differential water pressure. The new magnet is expected to be commissioned in the fourth quarter of 2012.

A G-band cryogenic MMIC heterodyne receiver module for astronomical applications

We report cryogenic noise temperature and gain measurements of a prototype heterodyne receiver module designed to operate in the atmospheric window centered on 150 GHz. The module utilizes monolithic microwave integrated circuit (MMIC) InP high electron mobility transistor (HEMT) amplifiers, a second harmonic mixer, and bandpass filters. Swept local oscillator (LO) measurements show an average gain of 22 dB and an average noise temperature of 87 K over a 40 GHz band from 140 to 180 GHz when the module is cooled to 22 K. A spot noise temperature of 58 K was measured at 166 GHz and is a record for cryogenic noise from HEMT amplifiers at this frequency. Intermediate frequency (IF) sweep measurements show a 20 GHz IF band with less than 94 K receiver noise temperature for a fixed LO of 83 GHz. The compact housing features a split-block design that facilitates quick assembly and a condensed arrangement of the MMIC components and bias circuitry. DC feedthroughs and nano-miniature connectors also contribute to the compact design, so that the dimensions of the moduleare approximately 2.5 cm per side.

Ceramic MEMS Designed for Wireless Pressure Monitoring in the Industrial Environment

This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC) were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing.

High-power solid-state cw dye laser

In the present paper we describe a high-power tunable solid-state dye laser setup that offers peak output power up to 800 mW around 575 nm with excellent long-time power stability and low noise level. The spectral width of the laser emission is less than 3 GHz and can be tuned over more than 30 nm. A nearly circular mode profile is achieved with an M(2) better than 1.4. The device can be integrated in a compact housing (dimensions are 60 × 40 × 20 cm(3)). The limitation of long-time power stability is mainly given by photo decomposition of organic dye molecules. These processes are analyzed in detail via spatially resolved micro-imaging and spectroscopic studies.

The trade-off between housing density and sprawl area: Minimising impacts to forest breeding birds

Increasing housing density is generally assumed to confer negative effects on forest breeding birds. This implies we should build at low density over the landscape to conserve these species. However, for a given human population, low-density development must cover a large area, resulting in sprawl. A pertinent question is then: at what housing density are the impacts of a given human population on forest biodiversity minimised? For a given human population, it is unclear whether the impacts on forest biodiversity are less where housing density is high and sprawl area is small or where housing density is low and sprawl area is large. We addressed this question using the abundance, species richness and evenness of forest birds in Ottawa, Ontario and Gatineau, Quebec, Canada. First, we counted breeding birds at 22 sites representing a range of housing densities. We then used these empirical measurements to estimate forest bird abundance, species richness and evenness in four hypothetical development scenarios representing the trade-off between housing density and sprawl area. With the exception of the Undeveloped scenario (i.e., continuous forest), forest birds and forest interior birds were most abundant in the Compact scenario and most speciose in the Semi-compact scenario, whereas forest edge birds were most abundant and speciose in the Dispersed scenario. All three bird groups were most even in the Compact scenario. We conclude that compact housing development (building at high density over a small area) minimises the impacts of a given human population on forest breeding birds.

Study on involute of circle with variable radii in a scroll compressor

A geometric model of scroll profiles, constructed from an involute of circle with variable radii, has been developed by using the theorem of planar orbiting mechanisms. Parametric studies have also been investigated in this study. When compared to the conventional scroll profile with the same suction volume, volume ratio and housing size, this new model demonstrates better reliability and efficiency because of a lower wrap height. Alternatively, a scroll type compressor with a more compact housing size can be achieved by using this new profile but keeping its wrap height the same as the conventional one. Furthermore, arc and line modifications have been built to provide wider design varieties. These are used to avoid interference at the center of the scroll pair and to boost the volume ratio of this new scroll profile.

An Evaluation of CO2 Emission Reduction based on the Supply of Condominiums in Central Kyoto

New residential needs have recently caused a construction boom in central areas of Japanese metropolises leading to population recovery and compact conversion in many cities, such as Kyoto. This study shows how central Kyoto has become compact by an investigation of condominiums. An evaluation of CO2 emissions based on the supply of condominiums was carried out. The investigation shows that the supply of condominiums within the central district of Kyoto has been increasing faster than that in the fringe district recently. Travel distance and modes of transportation are changed by such compaction process. The estimation shows that compact housing arrangement, which shortens traveling distance and changes the transportation modes of residents, helps to reduce CO2 emission in Kyoto. The results also indicate that, in the central district of Kyoto, the supply of dwelling units for households with more than two family members is more effective in reducing CO2 emission.

Using the vector sensors as receivers for underwater acoustic communications.

A vector sensor package (VSP) generally consists of three orthogonally oriented sensors and an omni directional hydrophone, all packed in a small compact housing. Because of its small size, the VSP might be more useful than a hydrophone array. In contrast to the hydrophone array, which has a non‐negligible vertical aperture and is difficult to deploy on an autonomous underwater vehicle (AUV), the VSP can be easily deployed on the AUV and used for underwater acoustic communications (UAC). However, the usefulness of the VSP depends on whether it provides the same spatial diversity as a hydrophone array. Hence, to address this question, this paper investigates the spatial correlation characteristics of the VSP and the bit error rates and/or output SNRs, based on at sea data, between the VSPs and the hydrophone array. The data were collected in May of 2009 on the New Jersey shelf. A hydrophone array and a VSP were deployed close to the ocean bottom and used for UACs. The source was towed at a slow speed, transmitting signals of various modulations at distances 0.5 to a few kilometers from the receivers. Initial results will be presented. [Work supported by the Office of Naval Research.]

60 GHz FM-CWR Using NRD guide for distance estimation

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. The main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by a leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 x 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than a distance of 0.7 m.

Fibre-coupled terahertz transceiver head

A very efficient and compact terahertz time-domain transceiver is presented that is well suited for tomography applications and other zero degree reflection measurements. The transceiver head consists of only one fibre coupled antenna that emits and receives the terahertz signal. An electrical filter circuit and a transimpedance amplifier are integrated into the compact metal housing of the transceiver head. The signal-to-noise ratio is 40 dB at 300 GHz whereas the required optical pump and probe power is below 1 mW. To demonstrate its operation the transceiver was used to measure the reflection spectrum of a dielectric mirror at normal incidence.

Development of a multichannel dispersion interferometer at TEXTOR

The design and main characteristics of 14-channel dispersion interferometer for plasma profile measurement and control in TEXTOR tokamak are presented. The diagnostic is engineered on the basis of modular concept, the 10.6 microm CO(2) laser source and all optical and mechanical elements of each module are arranged in a compact housing. A set of mirrors and retroreflectors inside the TEXTOR vacuum vessel provides full coverage of the torus cross section with 12 vertical and two diagonal lines of sight, no rigid frame for vibration isolation is required. Results of testing of the single-channel prototype diagnostic and the pilot module of the multichannel dispersion interferometer are presented.

Imaging photomultiplier array with integrated amplifiers and high-speed USB interface

Multianode photomultiplier tube (PMT) arrays are finding application as convenient high-speed light sensitive devices for plasma imaging. This paper describes the development of a USB-based "plug-n-play" 16-channel PMT camera with 16 bits simultaneous acquisition of 16 signal channels at rates up to 2 MSs per channel. The preamplifiers and digital hardware are packaged in a compact housing which incorporates magnetic shielding, on-board generation of the high-voltage PMT bias, an optical filter mount and slits, and F-mount lens adaptor. Triggering, timing, and acquisition are handled by four field-programmable gate arrays (FPGAs) under instruction from a master FPGA controlled by a computer with a LABVIEW interface. We present technical design details and specifications and illustrate performance with high-speed images obtained on the H-1 heliac at the ANU.

DEVELOPMENT OF COMPACT MINIATURE ANNULAR CENTRIFUGAL CONTACTOR FOR HOT CELL PLACEMENT

The development of a compact 1 cm rotor diameter annular centrifugal contactor suited for experimental testing of nuclear fuel reprocessing processes in a hot cell environment is described. Twelve-stage and 50-stage batteries of the 1 cm contactor are used to implement the extraction hot test processes for the cleanup of nuclear waste liquids in hot cells in Germany and China, respectively. The advances are: (1) a simple way of assembly and disassembly between the rotor and housing of the contactor, making manipulator operation easy; (2) compact multistage housing system; (3) easy inter-stage link; (4) compact miniature size of the contactor, taking up less space in the hot cell; (5) automatic sampling from housing of contactor in the hot cell; and (6) rotor speed control.

Miniaturized probe for femtosecond laser microsurgery and two-photon imaging.

Combined two-photon fluorescence microscopy and femtosecond laser microsurgery has many potential biomedical applications as a powerful "seek-and-treat" tool. Towards developing such a tool, we demonstrate a miniaturized probe which combines these techniques in a compact housing. The device is 10 x 15 x 40 mm(3) in size and uses an aircore photonic crystal fiber to deliver femtosecond laser pulses at 80 MHz repetition rate for imaging and 1 kHz for microsurgery. A fast two-axis microelectromechanical system scanning mirror is driven at resonance to produce Lissajous beam scanning at 10 frames per second. Field of view is 310 microm in diameter and the lateral and axial resolutions are 1.64 microm and 16.4 microm, respectively. Combined imaging and microsurgery is demonstrated using live cancer cells.

Distance estimation at 60 GHz band

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. Main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 times 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than 0.7 m.

The Probability of Single-family Dwelling Occupancy

Changing socioeconomic conditions are increasing the flexible workforce, such as home workers that are believed to internalize the need for home-work space in their housing consumption. Analysis of census data in thirteen Canadian metropolitan areas shows that households where one or both maintainers work from home have a greater propensity to reside in larger single-family detached houses than comparable households with maintainers who commute to work. The home-work variable increases the probability of single-family dwelling occupancy more than age, immigration, and household size, demographic variables generally highly associated with single-family dwelling occupancy. Although issues of causality cannot be empirically resolved here, if home work requires more space, it is one of the factors that would influence the tendency to continue to reside in the larger single-family dwellings. These dwellings have greater environmental impacts than more compact housing types that planners promote as part of their sustainability goals.

Toward a Miniaturized Wireless Fluorescence-Based Diagnostic Imaging System

Fluorescence-based spectroscopy and imaging techniques provide qualitative and quantitative diagnostic information on biological systems. In this paper, we report on the design, fabrication, and testing of a miniaturized wireless fluorescence imaging device for noninvasive clinical diagnosis and screening of diseases in the gastrointestinal tract. The system includes three submodules: optical imaging, electronics control and image acquisition, and information processing and transmission. These modules were individually developed and tested before being integrated into a battery-powered wireless device. The final integrated system is mounted in a customized, compact cylindrical housing. The performance of each individual module and the overall integrated system has been evaluated using fluorescent phantoms. It has been demonstrated that the miniaturized device can acquire spectrally resolved fluorescence images and transmit the image stream wirelessly. An important outcome of this feasibility study is the identification of important technological issues and pathways for future prototype development.

Cure for Urban Sprawl: Measuring the Ratio of Marginal Implicit Prices of Density-to-Lot-Size

S and local governments have long wrestled with sprawl, leading to the implementation of “smart growth” policies. The key principle underpinning smart growth policy is compact development to preserve open space, farmland, and critical ecological habitat. Many communities with commitments to controlling sprawl through smart growth policy are struggling with implementation. Their struggle emanates from lack of understanding about the causes of sprawl. Smart growth analysts increasingly emphasize higher-density housing as a possible cure for urban sprawl. Compact housing development may be a challenge because research suggests increasing preferences for lower density housing (Skaburskis; Gordon and Richardson). Higher-density housing could be achieved if communities could replicate the factors that increase the desirability of low-density housings. Burchell et al. suggest that typical single-family housing lots could be reduced in size by 20 to 25% if other qualities associated with a neighborhood were maintained. One popular strategy for the coexistence of compact lots and desirable neighborhood qualities is the implementation of a conservation subdivision ordinance. By clustering streets and homes closer together, developers of conservation subdivisions are able to set aside larger portions of the community, anywhere from 20 to 70%, as preserved open space (Arendt). As smart growth

Distance Estimation at 60 GHz

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. Main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 /spl times/ 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than a distance of 0.7 m.

On the development and testing of a guided ultrasonic wave array for structural integrity monitoring

The prototype of a guided ultrasonic wave array for the structural integrity monitoring of large, plate-like structures has been designed, built, and tested. The development of suitably small transducers for the excitation and measurement of the first antisymmetric Lamb wave mode Ao is described. The array design consists of a ring of 32 transducers, permanently bonded to the structure with a protective membrane, in a compact housing with the necessary multiplexing electronics. Using a phased addition algorithm with dispersion compensation and deconvolution in the wavenumber domain, a good dynamic range can be achieved with a limited number of transducers. Limitations in the transducer design and manufacture restricted the overall dynamic range achieved to 27 dB. Laboratory measurements for a steel plate containing various defects have been performed. The results for standard defects are compared to theoretical predictions and the sensitivity of the array device for defect detection has been established. Simulated corrosion pitting and a defect cut with an angle grinder simulating general corrosion were detected.