Abstract:
Apparatus and methods for testing sediment submerged in liquid and manufacturing the apparatus. The apparatus and methods of the present embodiment can provide for nano/micro characterization of mechanical properties of materials submerged in liquid, facilitating specimen preparation and installation, and can provide hydrated materials. The apparatus can include cell walls with optical magnifying lenses so that the materials can be viewed without the aid of a microscope.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application is a divisional of non-provisional patent application Ser. No. 13/616,163 filed on Sep. 14, 2012, which claims priority to provisional application No. 61/592,276 filed on Jan. 30, 2012, under 35 USC 119(e). The entire disclosures of both applications are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The embodiments disclosed herein relate generally to compression or tension testing of flocculated sediments, an aggregate mixture of clay minerals and biopolymers, referred to herein alternatively as “floc” or “sediment”. To test a floc, it should remain saturated and submerged in the formation solution. The floc must be easily isolated from other flocs for single floc geotechnical compression tests that can be made relatively rapidly on a large number of samples. A device to test a floc should have minimal and quantifiable frictional resistance to motion, minimal and quantifiable cantilever effect, and minimal, known, or quantifiable compressional resistance of the manipulator tips. Fine-grained sediment transport, deposition and consolidation of soft sediments is determined, in part, by a complex relationship between sediment makeup and geotechnical properties of clay-aggregates. Compression tests on soft sediment grains that are comprised of clay and polymers can help to better understand how contact interactions could alter the aggregate properties and influence sediment processes of transport, deposition and consolidation in estuarine and nearshore littoral environments. Compression tests can provide data that can be incorporated into numerical models, which can be used to predict sediment transport processes. In order to determine the compressive strength of clay aggregates, a highly sensitive load cell and mechanism to hold the small specimens (˜0.5 to 2 mm in diameter) in a controlled vertical plane are needed. Such a device would require a fluid receptacle within which the specimen is submerged and resting on a sample plate. The sample plate could be manipulated upward, via a stepper motor-driven lift that could push the specimen at a controlled and specified rate into the “punch” that could be connected to a load cell. The load cell could transfer the information to a computer that could quantify the force required to deform the specimen. Such a device could be used in nano/micro mechanical testing of individual flocs, or other small particles, in sizes that range from approximately 10 to approximately 5000 microns. The device could facilitate compression tests of flocs that are comprised of clay and polymers mixed in fresh or salt water for which the pH, or other chemistry, varies. The device could also facilitate imaging the deformation process in real-time, and could use that capability to correlate the floc compressive deformation process by generating a graphical representation of a force-displacement (i.e., compression) curve. The compression data could then be readily used to address the influence of contact interactions between flocs and deformation of those flocs in discrete element models of sediment transport. 
         [0003]    What is needed is an environmental cell for nano/micro mechanical and biomechanical testing to facilitate compression or tension tests of soft sediment aggregates that include clay and polymers mixed in fresh and salt water and which are retained in a liquid of the same salinity, alternatively for testing biological materials such as, for example, blood cells, virus, and bacteria, and also gels, foams, rubbers, surface coatings, and food. Currently, compression tests are not conducted on small aggregates that are comprised of soft, low-strength, materials. Also, there are no technologies available that can quantify the Young&#39;s modulus of these grains. Currently, these measurements are not made on soft, low-strength, materials. 
       SUMMARY 
       [0004]    This system and method of the present embodiment can enable testing of similar specimens in aqueous environments, such as food materials, cosmetics, chemicals, etc. The apparatus and methods of the present embodiment can provide for nano/micro mechanical testing of micro-sized materials submerged in liquid, facilitating specimen preparation and installation, and can provide hydrated materials. The apparatus can include cell walls with optical magnifying lenses so that the micro-sized specimens can be viewed without the aid of a microscope. For example, compression or tension tests of soft sediment aggregates and biological materials can be performed. The apparatus may have no frictional resistance between the parts that move to compress the flocs. The water bath can be maintained at a specific elevation and, because the water level or “the buoyant force” can be sensed by the load cell on, for example, but not limited to, an AGILENT TECHNOLOGIES® T150 Nano UTM. The UTM, or other similar device, includes, but is not limited to including, a frame that holds a load cell, a base plate, and a stepper motor that can move the base plate towards the load cell, and a computer that can transfer data from the load cell to a storage medium, reproducible and discernible results can be achieved. The 10× magnifiers can locate flocs and position them between the “compression punch” and “sample holder”. The clear imaging window can enable photography and movies of the floc during the compression test. A single floc or other material can be submerged in fluids of varied ionic strength and pH. At least two 10×, for example, viewing windows can be positioned at preselected angles to facilitate sample loading and alignment of small particles. The apparatus can enable real-time movies of compression tests to be captured. The apparatus can enable testing of compression in aqueous systems with, for example, but not limited to, an AGILENT TECHNOLOGIES® NanoUniversal Loading Frame and similar devices from other companies. The apparatus can be used to determine the fate and survivability of river-borne aggregates in estuarine and littoral zone waters. Further, the device can be used to quantify Young&#39;s moduli of small granular materials. The data produced by the device can be used to make predictions of grain interactions associated with sediment transport, specifically sediment transport of fine-grained sediment aggregates. The data may also be used to address the strength of similarly sized composite materials with low strength, such as beads, elastomers, food products and cosmetics. 
         [0005]    An environmental cell can be manufactured for nano/micro mechanical testing of micro-sized materials submerged in liquid, facilitating specimen preparation and installation, and providing hydrated materials. For example, compression or tension tests of soft sediment aggregates and biological materials can be performed. The apparatus can determine the compressive strength, elastic moduli or Young&#39;s moduli, of soft, sediment aggregates comprised of clay or clay and biopolymers. The apparatus can further collect data on clay aggregates as well as food material (for example, but not limited to, tofu and gelatin) which has similar compressive strength. 
         [0006]    The environmental cell can be coupled to a load cell (for example, but not limited to, Agilent UTM-150 with 50 nN force resolution). The load cell can be contained in a frame, inverted in the present embodiment, and can have a stepper motor. The environmental cell can be placed on a stage that is connected to the stepper motor, the stage also being connected to the environmental cell, the environmental cell containing the fluid and the sediment aggregate. The sediment aggregate is then positioned to contact the punch pin that is connected to the load cell, so that as the load cell is moved upward at a computer controlled rate (the strain rate), the load cell can detect the force of the sediment aggregate during displacement of the environmental cell. During this time period, a video camera collects images of the sediment aggregate, stills that can be used to produce a video. The displacement of the environmental cell is time-synched with the force determination and then this information is plotted as a force curve (force vs. displacement) in real-time on the load cell computer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a schematic diagram of the apparatus of the present embodiment; 
           [0008]      FIG. 2  is a CAD-drawing of the apparatus of the present embodiment; 
           [0009]      FIG. 3  is a virtual photographic representation of the apparatus of the present embodiment; 
           [0010]      FIG. 4  is a photographic representation of the apparatus of the present embodiment as it would be coupled to the load cell device and positioned with respect to the image capture system; 
           [0011]      FIG. 5  is a photographic representation of the apparatus of the present embodiment as it would be coupled to the load cell device and positioned with respect to the image capture system with indication that the compression test data and the images are transferred to different computers; 
           [0012]      FIG. 6  is a photographic representation of the flocs under compression during various phases of the displacement during the compression test; 
           [0013]      FIG. 7  is a graphical depiction of compressive strength of clay/organic matter mix that relates the images of  FIG. 6  to locations on the graph; 
           [0014]      FIG. 8A  is a flowchart of the method for assembling the apparatus of the present embodiment; 
           [0015]      FIG. 8B  is a flowchart of the method of collecting compression data using the apparatus of the present embodiment; and 
           [0016]      FIG. 8C  is a flowchart of the method of testing sediment data using the apparatus of the present embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The problems set forth above as well as further and other problems are solved by the present teachings. These solutions and other advantages are achieved by the various embodiments of the teachings described herein below. 
         [0018]    Referring now to  FIG. 1 , apparatus  100 , viewed from top view  130  and side view  140 , can include, but is not limited to including, base plate  101  made from, for example, DELRIN®, imaging window plate  103  made from, for example, acrylic, side plates made from, for example, acrylic, magnifying window magnifying lens  107  made of, for example, but not limited to, glass, sample holder  109  made from, for example, stainless steel, O-rings  113  made from, for example, butyl nitrile rubber, and compression punch  111  made from, for example, stainless steel. Fluid bath  115  can hold enough supernatant fluid to maintain the constant chemistry of the hydrated materials during the test. Apparatus  100  can provide a means to hold, locate and maintain properties of aggregate during compression tests of soft materials in an aqueous environment, and can automatically compute a force-displacement curve. This can enable tests of compressive strength while enabling the operator to view the placement of the floc and deformation of the floc through magnified lenses  107  and to capture images of the deformation process with a microscope through picture imaging window  103 . The determination of the elastic moduli, among other material properties, can be computed based on the force-displacement curve and the particle size information. 
         [0019]    Apparatus  100  can allow fluid to be maintained with the sample, which can be emplaced on a surface mounting rod, also referred to herein as sample support rod,  109  and viewed through 10× magnifying windows  103 , which can render apparatus  100  suitable for viewing micrometer-sized objects. The sample material can then be compressed under a controlled load and viewed with a microscope at high resolution/magnification so as to capture information on strain and deformation. Apparatus  100  can be coupled with, for example, but not limited to, a device to perform nanomechanical testing, for example, AGILENT TECHNOLOGIES® UTM T150, which can be used to measure compressive strength and therefore extend the capabilities from simple tensile strength tests. 
         [0020]    Referring now to  FIG. 2 , environmental cell  102  of apparatus  100  ( FIG. 1 ) can include blank side plates  137  and lens side plates  135  made of, for example, but not limited to, acrylic, that are connected to each other, for example, but not limited to, by gluing using, for example, but not limited to, acrylic solvent. Lens side plates  135  can be made of, for example, but not limited to, acrylic which can measure, but is not limited to measuring, approximately two inches in height, approximately 2.46 inches in width, and approximately 0.23 inches in width. Lens side plates  135  can include magnifying lens  107 , for example, but not limited to, 10× magnifying lenses, made out of, for example, but not limited to, glass, which can be fixed in place, for example glued, using, for example, but not limited to, 3M® 5200 adhesive sealant. Lens side plates  135  can also include lens recesses  139  can also include base plate  101  such as, for example, but not limited to, a DELRIN® plate glued to blank side plates  137  and lens side plates  135  using, for example, but not limited to, 3M® 5200 adhesive sealant can also include for example, but not limited to, No. 2006 O-rings  113 , and sample support rod  109  made from, for example, but not limited to, 316 stainless steel. The configuration and sizes of blank side plates  137  and lens side plates  135  can be different from the depicted embodiment. 
         [0021]    Referring now to  FIG. 3 , environmental cell  102  is shown in use including fluid bath  115 . Lens side plates  135 , 10× magnifying windows  107 , DELRIN® base plate  101 , and sample support rod  109  are also shown. 
         [0022]    Referring now to  FIG. 4 , embodiment  104  of environmental cell  102  ( FIG. 1 ) is shown from two points of view. Embodiment  104  can include video camera  201  that is attached to microscope  215  and load cell device  203  in an inverted position, compression punch  111 , flags  206  to maintain load cell in parked position, load cell  207 , clay floc  209 , stage manipulators  211 , magnifying view windows  213  to facilitate sample loading, orienting, and aligning with respect to compression punch  111 , by reorienting micromanipulator stage  217  with stage manipulators  211  to move environmental cell  102  that is connected to stage mount  219 , and belt-drive  221  that can migrate stepper motor plate  212  and micromanipulator staGe  217  upwards. During this process, as belt-drive  221  moves stepper motor plate  212 , micromanipulator stage  217 , and environmental cell  102  upwards, pre-aligned floc  209  can interact with compression punch  111  and load cell  203  to transfer force and displacement data to a load cell computer (not shown). Simultaneously, video camera  201  can capture imagery of the floc  209  deformation and can transport the images to an image processing computer (not shown). 
         [0023]    Referring now to  FIG. 5 , video camera  201  having connecting cables  245 , connecting video camera to image processing computer (not shown) is shown with respect to the load cell device  203 , for example, but not limited to, AGILENT TECHNOLOGIES® UTM150, and principle components of load cell  207 , compression punch  111 , environmental cell  102 , micromanipulator stage  217 , stage manipulators  211 , stepper motor plate  212 , and belt-drive  221  that can migrate micromanipulator stage  217  and environmental cell  102  upwards. Load cell  203  can collect data that are transferred to the data processing load cell computer (not shown); video camera  201  can transfer data to an image processing computer (not shown). 
         [0024]    Referring now primarily to  FIG. 6 , compression/deformation of floc  209  is shown in a series of images ((a)-(h)) that capture the vertical migration of environmental cell  102  ( FIG. 3 ) as sample support rod  109  ( FIG. 3 ) drives floc  209  into compression punch  111 . These images correspond to  FIG. 7 , the graph of load versus compression. During this process, floc  209  is submerged in the supernatant fluid within the environmental cell  102 , which can migrate upward to push floc  209  (and sample support rod  109 ) through supernatant fluid  115  and, eventually, into contact with floc  209  to the end of the test where environmental cell  102  ( FIG. 3 ) and sample support rod  109  ( FIG. 3 ) can reverse migration to unload floc  209 , which remains deformed (image (h) in  FIG. 6 ) 
         [0025]    Referring now to  FIG. 7 , graph  281  of load versus compression is shown for the compression of gray-green aggregate made of clay, e.g. illite, and organic matter, e.g. guar, mixed in salt-water of neutral pH. The graph shows the load in mN and compressive displacement of the load cell. Letters displayed along curve  283  correspond to images (a)-(h) in  FIG. 6 . 
         [0026]    Referring now primarily to  FIG. 8A , method  150  for assembling environmental cell  102  ( FIG. 2 ) can include, but is not limited to including, the steps of preparing two magnifying walls  135 , imaging window  103 , and side wall  137 , machining  151  compression punch  111  ( FIG. 1 ), cutting  153  sample support rod  109  ( FIG. 1 ) to radial and length dimensions and cutting threads inside sample support rod  109  ( FIG. 1 ) and o-ring grooves  113  ( FIG. 1 ) outside, cutting  155  a magnifying window, to mount magnifying lens  107  ( FIG. 1 ), and recesses in magnifying walls  135  ( FIG. 3 ), cutting  157  base plate  101  ( FIG. 1 ) and drilling a hole in base plate  101  ( FIG. 1 ) to accommodate sample support rod  109  ( FIG. 1 ), gluing  159  base plate  101  ( FIG. 1 ) to each of imaging window  103  ( FIG. 3 ), magnifying walls  135  ( FIG. 3 ), and side wall  137  ( FIG. 3 ) to form a water bath area, attaching  161  o-rings  113  ( FIG. 1 ) to the sample support rod  109  ( FIG. 1 ), attaching  163  sample support rod  109  ( FIG. 1 ) to a threaded attachment on a stage manipulator. 
         [0027]    Referring now to  FIG. 8B , method  250  for collecting compression data on a floc  209  ( FIG. 1 ) can include, but is not limited to including, the steps of attaching  251  threads of sample support rod  109  ( FIG. 1 ) to a threaded rod on a sample stage, sample support rod  109  ( FIG. 1 ) being positioned within environmental cell  102  ( FIG. 2 ), filling  253  environmental cell  102  ( FIG. 2 ) with a preselected volume of saturating fluid, installing  255  samples flocs  209  ( FIG. 1 ) to be evaluated on sample support rod  109  ( FIG. 1 ), if in manual mode, freeing  257  compression punch/load cell  111  ( FIG. 1 ) for movement from its flagged position, if in computer-controlled mode, migrating  259  the environmental cell towards compression punch  111  ( FIG. 1 ), aligning  261  compression punch  111  ( FIG. 1 ) with sample floc  209  ( FIG. 1 ) to be evaluated by rotating knobs on the sample stage using magnifying lens  107  ( FIG. 1 ) associated with environmental cell  102  ( FIG. 1 ) to assist viewing the alignment, and executing  263  a rate/load dependent computer compression test. 
         [0028]    Referring primarily to  FIG. 8C , method  350  ( FIG. 8C ) for testing sediment can include, but is not limited to including, the step of inserting  351  ( FIG. 8C ) compression punch  111  ( FIG. 4 ) into load cell  207  ( FIG. 4 ), while load cell  207  ( FIG. 4 ) is in the a parked position, for example, when flags  206  ( FIG. 4 ) are inserted into load cell  207  ( FIG. 4 ). Method  350  ( FIG. 8C ) for testing sediment can further include the steps of attaching  353  ( FIG. 8C ) environmental cell  102  ( FIG. 4 ) to stage mount  219  ( FIG. 4 ) resting atop micromanipulator stage  217  ( FIG. 4 ) that is attached to stepper motor plate  212  ( FIG. 4 ), loading  355  ( FIG. 8C ) environmental cell  102  ( FIG. 4 ) with the water from which the sediment is obtained, positioning  357  ( FIG. 8C ) the sediment on base plate  101  ( FIG. 1 ), and positioning  359  ( FIG. 8C ) the sediment below compression punch  111  ( FIG. 4 ) by adjusting stepper motor plate. Method  350  ( FIG. 8C ) can still further include the steps of moving  361  ( FIG. 8C ) the stepper motor plate towards compression punch  111  ( FIG. 44 ), computing  363  ( FIG. 8C ) a strain rate based on step  361  ( FIG. 8C ), measuring  365  ( FIG. 8C ) the sediment resistance of the sediment based on the strain rate and the stepper motor plate displacement, and recording  367  ( FIG. 8C ) the sediment resistance and the stepper motor plate displacement on a computer-readable medium. Method  350  ( FIG. 8C ) can optionally include the steps of collecting images of the sediment during the step of moving  361  ( FIG. 8C ) the stepper motor plate towards compression punch  111  ( FIG. 4 ), and computing any of the compression strength, the Young&#39;s modulus, and the elastic modulus of the sediment aggregate based on the sediment resistance and the images. Method  350  ( FIG. 8C ) can further optionally include the steps of adjusting the stepper motor plate by micromanipulators, and collecting the images through lens side plate  135  ( FIG. 3 ) of environmental cell  102  ( FIG. 4 ). Method  350  ( FIG. 8C ) can still further optionally include the steps of obtaining the sediment from any of a river, a laboratory, and an ocean bottom, and positioning the sediment on base plate  101  ( FIG. 4 ) using a pipette. Method  350  ( FIG. 8C ) can even further optionally include the steps of situating magnifying lenses  107  ( FIG. 4 ) at 90° angles to each other, aligning the magnifying lenses until the sediment is in line with compression pin  111  ( FIG. 4 ), and verifying the alignment based on the images. 
         [0029]    Referring again primarily to  FIGS. 8A and 8B , methods  150  ( FIG. 8A) and 250  ( FIG. 8B ) can be, in whole or in part, implemented electronically. Signals representing actions taken by elements of apparatus  100  ( FIG. 1 ) and other disclosed embodiments can travel over at least one live communications network (connected by communication cables  247  ( FIG. 5 )). Control and data information can be electronically executed and stored on at least one computer-readable medium accessible by cables  247  ( FIG. 5 ). Apparatus  100  ( FIG. 1 ) can be implemented to communicate with at least one computer node in at least one live communications network. Common forms of at least one computer-readable medium can include, for example, but not be limited to, a floppy disk, a flexible disk, a hard disk, magnetic tape, or any other magnetic medium, a compact disk read only memory or any other optical medium, punched cards, paper tape, or any other physical medium with patterns of holes, a random access memory, a programmable read only memory, and erasable programmable read only memory (EPROM), a Flash EPROM, or any other memory chip or cartridge, or any other medium from which a computer can read. Further, the at least one computer readable medium can contain graphs in any form including, but not limited to, Graphic Interchange Format (GIF), Joint Photographic Experts Group (JPEG), Portable Network Graphics (PNG), Scalable Vector Graphics (SVG), and Tagged Image File Format (TIFF). 
         [0030]    Although the present teachings have been described with respect to various embodiments, it should be realized these teachings are also capable of a wide variety of further and other embodiments.