The disclosure herein discloses an imaging method of internal defects in longitudinal sections of trees, and belongs to the field of nondestructive testing of trees. The method includes the following steps: with the propagation time of stress waves in a tree as input data, dividing an imaging plane into a predetermined number of grid cells to establish initial velocity distribution in the imaging plane; then performing multiple iterations using a linear propagation model; following each iteration, adjusting the velocity distribution in the imaging plane using the SIRT algorithm; constraining the velocity of each grid cell using maximum and minimum velocity constraints and fuzzy constraints based on grid cell groups, and ending iteration until the final velocity distribution is in good fit with the measured data; by comparing the velocity value of the grid cell at this moment with the reference value of the tested healthy tree, determining an abnormal grid cell; and then performing secondary smoothing processing on the grid cell imaging to obtain the defect location inside the tree. The method can accurately detect the defective area of the tree, and has less false detection areas and good imaging effect.

The present invention discloses a system for measuring the mechanical properties of sea floor sediments at full ocean depth. The system includes an overwater monitoring unit and an underwater measurement device, where the underwater measurement device includes an observation platform and a measuring mechanism; the observation platform includes a frame-type body and a floating body, a wing panel, a floating ball cabin, a leveling mechanism, a counterweight, and a release mechanism mounted on the frame-type body; the floating ball cabin seals a circuit system; the leveling mechanism adjusts the underwater measurement device horizontally on the sea floor when the frame-type body reaches the sea floor; the release mechanism discards the counterweight for recovery of the unit after the underwater measurement device completes the underwater operation; the measuring mechanism includes at least one of a cone penetration measuring mechanism, a spherical penetration measuring mechanism, and a vane shear measuring mechanism, or a sampling mechanism.

A device for measuring strength and strain softening parameters of a saturated clay sample based on full-flow penetration belongs to the technical field of geotechnical, geological and environmental research. The device mainly comprises two parts: an overlying pressure loading system and a full-flow penetration system. The present invention mainly aims at the problem of incomplete backflow of the soil in the measurement of soil strength and strain softening parameters with a full-flow penetrometer for saturated clay, and applies the working principle of a traditional consolidometer to vertically pressurize a soil sample to ensure the backflow of the soil, thereby improving the applicability of the full-flow penetrometer in the measurement aspect of the soil strength and the strain softening parameters and having important practical value for test research and marine engineering design.

An apparatus for performing a contact mechanics test by engaging multiple styluses with a substrate through a contact load that is applied by a load applicator and transferred to the styluses through a stylus load transfer mechanism. This apparatus allows the styluses to be positioned in close proximity to allow for a smaller and more compact apparatus, with less uncertainty on the magnitude of the engagement load being applied to each stylus. Ultimately, this provides a more portable apparatus for testing of material properties.

A device for measuring strength and strain softening parameters of a saturated clay sample based on full-flow penetration belongs to the technical field of geotechnical, geological and environmental research. The device mainly comprises two parts: an overlying pressure loading system and a full-flow penetration system. The present invention mainly aims at the problem of incomplete backflow of the soil in the measurement of soil strength and strain softening parameters with a full-flow penetrometer for saturated clay, and applies the working principle of a traditional consolidometer to vertically pressurize a soil sample to ensure the backflow of the soil, thereby improving the applicability of the full-flow penetrometer in the measurement aspect of the soil strength and the strain softening parameters and having important practical value for test research and marine engineering design.

System for conducting measurements of friction of a chosen material with reduced errors. The system includes a sample holder, a bushing accommodating such holder while permitting reversible repositioning of the holder along a bushing axis, a horizontal force sensor, a vertical force sensor, a sample holder pusher and a subsystem including a linear vertical bearing (disposed in the bushing and separating the holder from the bushing) and/or a horizontally-sliding element between the rod pusher and the vertical force sensor. The subsystem is structured to reduce a rocking motion of the holder in the bushing caused by a relative motion between the sample and an auxiliary body brought in contact with the sample. The method for performing measurements with such system.

A device for testing a rotor blade of an aircraft. The device is configured to receive and secure a shaft of the rotor blade. Once secured, the device is configured to allow for inputting combined loads and bending moments into the rotor blade to simulate the rotor blade behavior in flight. A testing assembly is also disclosed that includes the device and the rotor blade and methods of use that provide for testing the rotor blade.

A loading device, a monitoring system, and a method thereof can measure stiffness of a structural member (SM), such as a bone, and monitor progress or property over time. The loading device includes two types of displacement sensors, one type being an antenna. As the SM, which is in a magnetic or electromagnetic field and electromagnetically coupled to the antenna without contact, undergoes displacement under known loads, characteristics of the electromagnetic field coupling between the antenna and the SM change over time due to the displacement of the SM. The shift in the characteristics of the electromagnetic field coupling between the antenna and the SM can be used to determine the displacement of the SM. Based on the changes in the displacement over time, diagnosis of the SM being monitored over an evaluation period can be made.

A twin-disc tribometer assembly includes a first sample drive shaft arranged to receive a first sample disc and a second sample drive shaft arranged to receive a second sample disc; a first drive motor configured to rotate the first drive shaft and a second motor arranged to rotate the second drive shaft. The first and second drive shafts are configured to be positioned relative to each other such that a sample disc mounted on the first drive shaft will make a point contact with a sample disc on the second drive shaft as the drive shafts rotate. The assembly is configured to allow the shafts to rotate relative to each other in a non-continuous reciprocating motion or a non-collinear motion where one sample disc is tilted with respect to the other.

A test apparatus comprises a probe movably mounted relative to a carrier. The probe comprises an end portion with a surface area of about 5 mm.sup.2 or less. The test apparatus can be used in methods of determining a crush strength of an edge of a substrate. Methods can comprise aligning the probe with a test location of the substrate at a predetermined angle relative to a probe axis. Methods can further comprise applying a mechanical force to the test location with the probe in the direction of the probe axis. Also, methods can comprise increasing the mechanical force applied by the probe until the substrate cracks or a predefined force applied by the probe is reached. Based on the mechanical force applied by the probe, a crush strength of an edge can be determined.