Patents Assigned to University of Waterloo
  • Patent number: 5782583
    Abstract: The barrier is waterproof, and is used to contain contaminated groundwater within an enclosure. Steel elements are pile driven, the elements having rolled-over forms (5,6) which inter-engage. Upon inter-engagement, an enclosed cavity (90) is created which extends from top to bottom of the piled elements. A scraper (19) on the junior element (8) cleans dirt out of the cavity as the junior is driven down alongside the adjacent senior element (7). The cavity may be cleaned out by inserting a hose pipe to the bottom of the cavity (90) and flushing through with water. Then, a sealant is injected into the cavity, using an injection tube. The inter-engagement of the edge forms (5,6) of the elements is such that the cavity formed by the inter-engagement is constrained to its nominal size and shape throughout the whole height of the barrier.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: July 21, 1998
    Assignee: University of Waterloo
    Inventor: E. S. Vales
  • Patent number: 5770718
    Abstract: A cDNA for apt from a plant, particularly A. thaliana has been isolated, purified and characterized. The cDNA is useful for the generation of APRT-deficient mutants and as a probe for APRT cDNAs in other plants.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: June 23, 1998
    Assignee: University of Waterloo
    Inventor: Barbara Moffatt
  • Patent number: 5732008
    Abstract: A low power high performance adder using a conditional sum adder (CSA) architecture and complementary pass logic (CPL) implementation. The adder comprises a plurality of blocks, each block including a conditional sum cell and an output multiplexer. Each block except the first, also comprises a block of 2:1 multiplexers intermediate the conditional sum cell and the output multiplexer. The adder according to the present invention operates with lower power consumption and at greater speed than prior art adder architectures.
    Type: Grant
    Filed: December 4, 1995
    Date of Patent: March 24, 1998
    Assignee: The University of Waterloo
    Inventors: Issam S. Abu-Khater, A. Bellaouar, Mohamed I. Elmasry
  • Patent number: 5705787
    Abstract: An in-torch vaporization sample introduction system for introducing a sample to be analyzed into a spectrometer, comprising a sample holder means for carrying the sample to be analyzed, a modified Fassel-type torch having a plasma fed by inert gas through outer and intermediate feed channels in an enlarged gas tube, an inner axial tube having one end open adjacent the plasma and an opposite end open for receiving the sample holder for feeding the sample to the plasma, the inner axial tube tapering to a reduced diameter adjacent the one end to form a well defined channel for feeding the sample to the plasma. The sample holder is positioned in the inner axial tube a predetermined distance below the plasma, and the opposite end of the inner axial tube is sealed for vaporizing the sample.
    Type: Grant
    Filed: August 12, 1994
    Date of Patent: January 6, 1998
    Assignee: The University of Waterloo
    Inventor: Vassili Karanassios
  • Patent number: 5649373
    Abstract: A novel shoe structure, particularly a ballet shoe, is provided in which an elongate flat leaf spring element is provided associated with the sole of the shoe structure. The elongate leaf spring extends from the toe region of the shoe structure beyond the location of the metatarsal-phalangeal (m-p) joints of the wearer, so as to provide a mechanical power assist to the wearer at the m-p joints.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: July 22, 1997
    Assignee: University of Waterloo
    Inventors: David A. Winter, Paula A. Dozzi
  • Patent number: 5641020
    Abstract: The treatment system involves the use of hydrofracturing in drilled boreholes over the treatment area. The hydrofracturing fluid contains treatment material, of the kind that causes chemical breakdown of the contaminant. The breakdown leads to a contaminant concentration of zero in the hydrofracks, and therefore the contaminant diffuses towards the hydrofracks, where it is in turn broken down. Calculations and measurements indicate whether natural cracks in the ground are far enough apart to make hydrofracturing worthwhile. A formula indicates, from an assessment of diffusion coefficients, etc, whether the contaminant will be rendered safe within a given time period.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: June 24, 1997
    Assignee: University of Waterloo
    Inventors: John Anthony Cherry, Beth L. Parker
  • Patent number: 5633194
    Abstract: A low temperature ion-beam assisted deposition process, comprising the steps of cleaning at least one substrate, subjecting the substrate to a vacuum of at least 2.times.10.sup.-4 Torr, heating the substrate to a temperature of at least 280.degree. C., and directing an ion beam at the substrate, wherein the ion beam comprises ion-associated gas molecules of Si or Ge, so as to grow a thin epitaxial film of Si or Ge on the substrate.
    Type: Grant
    Filed: April 19, 1995
    Date of Patent: May 27, 1997
    Assignee: The University of Waterloo
    Inventors: C. R. Selvakumar, S. Mohajerzadeh, D. E. Brodie
  • Patent number: 5624552
    Abstract: A barrier of sheet metal elements in pile-driven into the ground in the path of contaminated groundwater. The barrier serves to funnel the contaminated water into an aperture in the barrier, in which is located a receptacle. A caisson is driven into the ground at the aperture, and the soil etc. removed from inside. A receptacle is lowered into the empty caisson, and a seal is provided whereby, when the caisson is removed the receptacle is sealed to the barrier. Baskets containing treatment material may be lowered into and hoisted out from the receptacle. Rubber seals seal the basket to the receptacle.
    Type: Grant
    Filed: February 22, 1994
    Date of Patent: April 29, 1997
    Assignee: University of Waterloo
    Inventors: Enoch S. Vales, John A. Cherry, David J. Lang
  • Patent number: 5605551
    Abstract: A high conversion of biomass, such as wood, sawdust, bark, or agricultural wastes, to liquids is obtained bypyrolysis at short reaction tines in a reactor capable of high heat transfer rates; the reactor being of the fluidized bed, circulating fluidized bed or transport type in which the conveying gas contains low and carefully controlled amounts of oxygen, allowing a reaction system with low concentrations of carbon monoxide or flammable gases with a resulting improvement in operating safety and potential improvement in thermal efficiency and capital costs. The oxidation steps may be carried out in one or two stages. The resulting liquid product may be used as an alternative liquid fuel or as a source of high-value chemicals.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: February 25, 1997
    Assignee: University of Waterloo
    Inventors: Donald S. Scott, Jan Piskorz, Desmond Radlein, Piotr Majerski
  • Patent number: 5605634
    Abstract: The system places traces of nutrients and other treatment substances in the ground, in the path of an on-coming plume of contaminated groundwater. Boreholes placed across the plume contain respective diffusion tubes, the tubes being of e.g LDPE, or dialysis tubing. The remediation substance is circulated (pumped) through the diffusion tubes periodically. The remediation substance diffuses through the LDPE into the water in the borehole, and thence into the plume and is carried into the aquifer.
    Type: Grant
    Filed: April 24, 1995
    Date of Patent: February 25, 1997
    Assignee: University of Waterloo
    Inventors: Ryan D. Wilson, Douglas M. Mackay
  • Patent number: 5602774
    Abstract: A SRAM includes an ECL input buffer connected between an address bus and a W-OR predecoder array. The logic output of the W-OR predecoder array is applied to a level translator array and level shifted. The level shifted output of the level translator array is supplied to a plurality of self-resetting word-line decoder and driver (WLDD) circuits. The WLDD circuits supply activation pulses to selected blocks of memory in a memory cell array. Sense amplifiers sense and latch-in the data stored in the activated selected blocks of memory. The design of the W-OR predecoder array, level translator array, WLDD circuits and sense amplifiers is such to reduce the overall power consumption of the SRAM.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: February 11, 1997
    Assignee: University of Waterloo
    Inventors: Muhammad S. Elrabaa, Mohamed I. Elmasry
  • Patent number: 5561197
    Abstract: A process is provided for the hydrogenation of carbon-carbon double bonds in polymers by treatment of the polymer in solution with hydrogen in the presence of osmium-based catalysts.
    Type: Grant
    Filed: June 27, 1995
    Date of Patent: October 1, 1996
    Assignee: University of Waterloo
    Inventors: Garry L. Rempel, Neil T. McManus, John S. Parent
  • Patent number: 5548288
    Abstract: An improved current cell and current switch is described for use in digital-to-analog converters and other current mode circuits. The current switch is implemented using BiCMOS circuitry which is characterized by an absence of base current error and a switching speed which is approximately twice as fast as the switching speed of prior art MOS-based switches. According to one embodiment, the current cell is implemented in BiCMOS which offers higher output resistance, smaller minimum voltage, and improved accuracy over prior art MOS-based self-calibrated current cells. According to another embodiment, the current cell is implemented in CMOS and is characterized by a significant reduction in charge injection, leakage current and error due to coupling of the cell output voltage back to the storage node, as compared with prior art MOS-based current cells.
    Type: Grant
    Filed: December 22, 1993
    Date of Patent: August 20, 1996
    Assignee: University of Waterloo
    Inventor: Bosco Lueng
  • Patent number: 5534154
    Abstract: Water contaminated with halogenated organics, including chloroform, trichloroethane, solvents, pesticides, etc. is treated by passing the water through a permeable mixture of activated carbon and iron fillings. When the mixture is brought to a negative Eh voltae, the metal causes the contaminants to undergo chemical breakdown. The activated carbon acts to retard the contaminant, giving it a long residence time close to the iron. The negative Eh conditions demand oxygen exclusion, such that a favoured application is to place the mixture in a trench below the water table in an aquifer, in the path of a plume of contaminant. The mixture may also be contained in a tank above, or in, the ground. An inert filler material, such as sand, may be included in the mixture.
    Type: Grant
    Filed: October 22, 1993
    Date of Patent: July 9, 1996
    Assignee: University of Waterloo
    Inventor: Robert W. Gillham
  • Patent number: 5525916
    Abstract: An All-N-Logic (ANL) high-speed single-phase dynamic CMOS logic utilizing all-N-logic blocks. According to a first embodiment, a 2:1 frequency divider is provided using the ANL CMOS logic of the present invention. According to a second embodiment, a pipelines 8-bit carry generator is provided utilizing five stacked NMOS gates.
    Type: Grant
    Filed: April 10, 1995
    Date of Patent: June 11, 1996
    Assignee: The University of Waterloo
    Inventors: Richard Gu, Mohamed Elmasry
  • Patent number: 5514279
    Abstract: A system for treating groundwater contaminated with acidity or other contaminants is disclosed. The system involves excavating a trench into the aquifer in the path of the contaminant plume, and placing a body of active material in the trench. The active material depends on the particular contaminant: organic carbon may be used when the contaminant is ferrous sulphate, or hexavalent uranium oxide, or dissolved nitrate; pyrite or elemental iron may be used when the contaminant is eg chromium oxide. The active material causes the contaminant, by chemical reaction, to change its oxidation-reduction state, and to precipitate harmlessly in the body of material.
    Type: Grant
    Filed: October 27, 1994
    Date of Patent: May 7, 1996
    Assignee: University of Waterloo
    Inventors: David W. Blowes, Carol J. Ptacek
  • Patent number: 5496741
    Abstract: A device and process for increasing analyte concentration in a sorbent from a source of analytes contained in a sample uses means for increasing a temperature differential between the sample and the sorbent. The sorbent can be a polymeric coating on a substrate. The sorbent is located in a headspace of the sample and has internal cooling means such as liquid carbon dioxide so that the sorbent can be cooled relative to the sample. Preferably, the sample is heated to further increase the temperature differential between the sample and the sorbent. As the temperature differential increases, a partition coefficient of the sorbent/sample also increases. Preferably, the sorbent is located in a headspace of the sample. Previously, for certain analytes, the partition coefficient was too low and the concentration of analytes extracted into the sorbent from the sample was insufficient to provide an accurate measurement of concentration.
    Type: Grant
    Filed: April 14, 1994
    Date of Patent: March 5, 1996
    Assignee: University of Waterloo
    Inventor: Janusz B. Pawliszyn
  • Patent number: 5490743
    Abstract: For providing an in-ground system for treating contaminated groundwater, of the funnel-and-gate type, a cylindrical caisson is driven into the ground. The native soil is augered out of the caisson, and porous treatment material substituted. The caisson is then withdrawn, leaving a prism of porous treatment material in the ground. A sheet metal barrier element is inserted into the ground, one portion of the element extending into the prism and the other portion into the surrounding soil. More prisms are provided as further treatment gates, and more barrier elements are arranged to funnel the groundwater through the gates.
    Type: Grant
    Filed: June 20, 1994
    Date of Patent: February 13, 1996
    Assignee: University of Waterloo
    Inventor: Enoch S. Vales
  • Patent number: 5487622
    Abstract: Contaminated groundwater is treated in-situ, by funnelling the water through a gate or gates (23) in a watertight in-ground wall (18). Treatment material in the gate (23) breaks down the contaminant, or otherwise removes the contaminant from the flowing water. A removable caisson is first driven into the ground, excavated, and then a receptacle, for the treatment material, is lowered into the hollow interior.
    Type: Grant
    Filed: October 20, 1994
    Date of Patent: January 30, 1996
    Assignee: University of Waterloo
    Inventors: John A. Cherry, Enoch S. Vales, Robert W. Gillham
  • Patent number: 5456550
    Abstract: A permeable wall (4) is located in the material of an aquifer (2), in the path of an approaching plume (3) of a contaminant (eg a chlorinated solvent). The wall comprises a body (7) of permeable filler material, eg sand and gravel, which is placed in a trench (5) that has been cut down into the aquifer material. Biologically-aided breakdown of the contaminant is aided by the presence of nutrients in the groundwater, and injection ports (18) are provided in the wall, through which the nutrients are injected periodically. The permeability of the wall helps the injected nutrients to spread laterally through the plume. The injected substances are contained in a volume of water; this water may be water which has been extracted from the trench, draw-off wells (9) being provided in the trench for that purpose. A second permeable wall (29) may be provided downstream for injection of eg air.
    Type: Grant
    Filed: January 21, 1992
    Date of Patent: October 10, 1995
    Assignee: University of Waterloo
    Inventor: John F. Devlin