Require Hardware Modifications Research Articles

Dispensing an enzyme-conjugated solution into an ELISA plate by adapting ink-jet printers

The rapid and precise delivery of small volumes of bio-fluids (from picoliters to nanoliters) is a key feature of modern bioanalytical assays. Commercial ink-jet printers are low-cost systems which enable the dispensing of tiny droplets at a rate which may exceed 10 4 Hz per nozzle. Currently, the main ejection technologies are piezoelectric and bubble-jet. We adapted two commercial printers, respectively a piezoelectric and a bubble-jet one, for the deposition of immunoglobulins into an ELISA plate. The objective was to perform a comparative evaluation of the two classes of ink-jet technologies in terms of required hardware modifications and possible damage on the dispensed molecules. The hardware of the two printers was modified to dispense an enzyme conjugate solution, containing polyclonal rabbit anti-human IgG labelled with HRP in 7 wells of an ELISA plate. Moreover, the ELISA assay was used to assess the functional activity of the biomolecules after ejection. ELISA is a common and well-assessed technique to detect the presence of particular antigens or antibodies in a sample. We employed an ELISA diagnostic kit for the qualitative screening of anti-ENA antibodies to verify the ability of the dispensed immunoglobulins to bind the primary antibodies in the wells. Experimental tests showed that the dispensing of immunoglobulins using the piezoelectric printer does not cause any detectable difference on the outcome of the ELISA test if compared to manual dispensing using micropipettes. On the contrary, the thermal printhead was not able to reliably dispense the bio-fluid, which may mean that a surfactant is required to modify the wetting properties of the liquid.

English

There is a need to measure deep in situ moisture conditions for all types of waste storage facilities in a safe, cost effective, practical, and efficient manner. This paper describes the Deep Diviner moisture probe, a deep capacitance moisture sensor, which has been developed by the authors with the assistance of the Canada Industrial Research Assistance Program (IRAP). The deep capacitance moisture probe uses the Diviner 2000, a portable capacitance soil moisture monitoring sensor manufactured by Sentek Sensor Technologies. This portable probe was developed for irrigation management, and is a nonradioactive sensor. Development of the deep capacitance moisture probe involved modifying the Diviner 2000, which has a limited depth range of 1.6 m, to allow the measurement of volumetric water content to depths of 40 m or 50 m, and possibly deeper. A winch / cable assembly was developed to lower the sensor down within a PVC access tube to allow for fully automated measurement of in situ moisture contents at user specified depth intervals, each of which are recorded on a portable datalogger. The prototype of the deep capacitance moisture probe was tested both in the laboratory and in a full-scale field situation to ensure the required hardware modifications were functional. Full scale field testing was also completed on the prototype. The results of this testing show that the deep capacitance moisture sensor is capable of measuring the water content of till and sand materials to depths of 6 m. This paper describes the development and testing of the deep capacitance moisture. ______________________ 1 Paper presented at the 7 th International Conference on Acid Rock Drainage (ICARD), March 26-30, 2006, St. Louis MO. R.I. Barnhisel (ed.) Published by the American Society of Mining and Reclamation (ASMR), 3134 Montavesta Road, Lexington, KY 40502 2 Bonnie Dobchuk is a Geotechnical Engineer with O’Kane Consultants Inc., Saskatoon, SK S7N 4S1 Canada. 3 S. Lee Barbour is a Professor in the Department of Civil and Geological Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 Canada. 4 Jeff Dobchuk is President of Convergent Motion Control, Inc., Saskatoon, SK S7H 1N6 Canada. 5 Mike O’Kane is President of O’Kane Consultants Inc., Calgary, AB T3H 3C8 Canada. 7 th International Conference on Acid Rock Drainage, 2006 pp 528-538 DOI: 10.21000/JASMR06020528

A bulk microfabricated multi-axis capacitive cellular force sensor using transverse comb drives

This paper presents design, fabrication and calibration results for a novel 2-DOF capacitive force sensor capable of resolving forces up to 490 µN with a resolution of 0.01 µN in x, and up to 900 µN with a resolution of 0.24 µN in y. A simple fabrication process using deep reactive ion etching (DRIE) on silicon-on-insulator (SOI) wafers forms the 3D high aspect ratio structure. A transverse mode comb drive movement is used to greatly improve device sensitivity. Among other advantages of the developed process is a dice-free release of wafer structures, allowing fragile structures to be individually packaged. Notching or footing effects and bowing effects are well-known problems in DRIE on SOI wafers. Techniques to overcome notching and bowing effects using a PlasmaTherm SLR-770 etcher are presented that do not require hardware modifications. The application of the force sensor is for providing real-time force feedback during individual cell manipulation tasks.

A high-aspect-ratio two-axis electrostatic microactuator with extended travel range

The design, fabrication, modelling, and control of a two-axis electrostatic microactuator for precision manipulation tasks is described. A high-yield fabrication process using deep reactive ion etching (DRIE) on silicon-on-insulator (SOI) wafers forms the 3-D high aspect ratio transverse comb drives that produce a relatively large electrostatic force. The structure is suspended by removing the substrate beneath the comb drives, therefore, a ground plane is not needed in order to compensate for electrostatic levitation. Among other advantages of the developed process is a dice-free release of wafer structures, allowing fragile structures to be individually packaged. Notching or footing effects and bowing effects are well-known problems in DRIE on SOI wafers. Techniques to overcome notching and bowing effects using a PlasmaTherm SLR-770 etcher are presented that do not require hardware modifications. A capacitive position sensing mechanism, capable of measuring displacements up to 4.5 μm with a resolution of 0.01 μm in both X and Y is integrated to provide position feedback. A nonlinear model inversion technique is proposed for nonlinear electrostatic microactuation system identification and improving system linearity and response. Pull-in instability limits the travel distance of transverse comb drive actuators. Using a nonlinear model inversion technique, a stable travel distance of 3.7 μm with a 4.5 μm gap has been achieved.

Scaling criteria for the development of an acoustically stabilized dump combustor

Acoustic stabilization of combustion in a dump configuration results in completion of combustion in a relatively short residence time with simultaneously low emissions of oxides of nitrogen, carbon monoxide, and hydrocarbons. Acoustically stabilized combustion is also a potential means for achieving closed-loop active control of combustion. Therefore, a promising burner configuration identified through laboratory bench-top experiments was developed and scaled up for application as an afterburner for a starved-air incinerator with the objective of providing a compact device capable of achieving pollutant emissions performance better than required by current International Maritime Organization regulations. In the absence of established scaling criteria, factors governing vortex generation and jet mixing theory were examined. These provided useful guidelines for burner design as the dump combustor was successively scaled up from a 4.75 kW laboratory experiment to a nominal 700 kW unit tested on a starved-air incinerator. Key parameters considered were the central air jet velocity, jet diameter (and area) acoustic driving frequency, and characteristic jet mixing time. Burner performance was maintained or improved as both jet velocity and jet area were increased approximately as the square root of burner scale. This resulted in increases in the acoustic driving frequency and burner pressure drop with scale, which have implications for development of even larger burners using this technology. Initial development was conducted using simulated low-Btu gas mixtures at ambient temperature. Application as an afterburner required hardware modifications to accommodate higher gas volumes at higher temperatures. Despite significant changes in burner geometry, coherent vortex generation was established by acoustic excitation and continued to effect reductions in NO x and CO emissions. The higher combustion temperatures encountered with hot simulated and real pyrolysis products led to higher CO and NO x emissions, but emission performance continued to exceed applicable regulatory guidelines by a substantial margin.

Aggressive region growing filtering for speckle reduction in ultrasound images

Speckle noise is present in all conventional ultrasound images, and complicates the process of diagnosis as it can mask small but diagnostically significant features. Speckle reduction techniques can be applied prior to image formation [e.g., Chen et al., J. Ultrasound Imag. 18(2), 122–139 (1996)] or after image formation. Post-formation techniques can be implemented in software, whereas pre-formation techniques generally require hardware modifications. The approach described here is applied after image formation, and consists of two steps. In the first step, small ‘‘seed’’ regions are defined around each pixel in the image, and a homogeneity criterion is used to guide a procedure which identifies the maximal-size homogeneous region containing the pixel of interest. Once determined, this region is smoothed using a truncated arithmetic mean filter. Results on synthetic and real images demonstrate that this method preserves the sharpness of image edges yet reduces speckle noise, and compares well with weighted median filtering [Loupas et al., IEEE Trans. Circuits Syst. 236, 129–135 (1989)] and homogeneous region growing median filtering [Koo and Park, J. Ultrasound Imag. 13, 211–237 (1991)]. [Work supported by NSF and the Carl M. Hansen Foundation.]

Fast, portable application mirroring

Previous implementations of an application mirror-a tool that lets two computers interactively share an application-have required hardware modifications, been restricted to one platform, and suffered from slow data throughput. The authors overcome these drawbacks by transmitting only those events that affect a shared application's status.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Multichannel analyser interface to an 8 bit microcomputer system

A practical method of interfacing a multichannel analyser (MCA) to an 8 bit microcomputer system is reported. The MCA does not require hardware modifications or a computer interface option. A device driver was written and incorporated in the operating system to enable the transmitted spectral data to be read and processed. The hardware and the software interface are described.

Volumetric compensation through the machine controller

Compensation is a cost effective method of correcting for machine tool systematic errors. Although controller manufacturers are providing increasingly more sophisticated compensation, they do not include for all geometric sources of error for the variety of 3and 5-axis configurations that exist today. A small number of comprehensive PC-based compensation systems exist, requiring hardware modifications and interface electronics to interact with the position control loop, which can be expensive and difficult to implement. This paper describes a general purpose error compensation system that is located and runs inside the machine controller. The system has been designed to run on a modem open architecture Computer Numerical Controller, namely an Osai UK series 10 controller. One of the facilities within this controller is a DOS Real Time Interface, which allows a user to develop custom applications that can run and communicate with various parts of the NC system in real time. Compensation software, based on a 5-axis geometric error compensation system produced at the University of Huddersfield, has been developed to run in the DOS real time environment. The system has been applied to three machine tools and the volumetric accuracy significantly improved. Requiring only a simple software installation, the system is also shown to be inexpensive, simple and fast to implement.