Described is a method for simulating the ageing of a predetermined fabric comprising the following steps: preparing two specimens of said predetermined fabric, subjecting said specimens to an abrasion process by mutual rubbing, subjecting a first of said specimens to a test by means of an Elmendorf type lacerometer according to the direction of the weft of said predetermined fabric, subjecting a second of said specimens to an Elmendorf test according to the direction of warp of said predetermined fabric, comparing the results of said Elmendorf tests with a reference value relative to an Elmendorf test performed on the same predetermined fabric not subjected to any abrasion process.

A tester for evaluating pullout load capacity and bond quality of anchor bolts embedded in concrete includes a Schmidt hammer for measuring a rebound number and an ultrasonic pulse velocity tester for measuring the transit time of a pulse transmitted through concrete surrounding an anchor bolt. The rebound number and the transit time are combined and matched against a database record which identifies the pullout load capacity and the bond quality. The transit time is matched to thresholds of transit times associated with porosity, internal cracking, air voids, and water pockets located around the embedded anchor bolt. The Schmidt hammer is further modified by the incorporation of a digital level for measuring the vertical and horizontal angles of inclination of the plunger with the concrete surface, a guide tube for supporting the plunger, and by using a convex plunger tip for improved registration with anchor bolt head.

A device for assessing the solidity of a material comprising an ancillary tool (2) having an end (2B) in the form of a point or blade, an impactor (4) for striking the ancillary tool (2), a sensor (12) and a processing unit (30). The ancillary tool (2) is placed between a material (8) and the impactor (4) and transmits the impact force generated by the impactor (4) to the material (8). The sensor (12) is capable of measuring a quantity from among the impact force and the deformation of the impactor, and of supplying a measurement signal. The processing unit (30) is suitable for calculating, from the measurement signal, an indicator representative of the solidity of the material (8). The indicator corresponds to the duration of a time window between the first peak (P1) of maximum amplitude of the measurement signal and the second peak of maximum amplitude (P2).

The present invention is directed to a system for determining the structural characteristics of a machine tool. The system comprises an excitation device configured to induce a dynamic excitation in a tool of the machine tool, a preloading device configured to generate a static force on the tool, and a sensing device for acquiring a set of data based on which the structural characteristics of the tool can be determined.

Provided are a striking device and a natural frequency measuring device capable of simply and accurately measuring a natural frequency of a system including force detector. The striking device includes an arm capable of swinging around a spindle, and a steel ball arranged in an end part of the arm on a side opposite to the spindle. The spindle is supported by a supporting part capable of lifting up and down relative to a post erected on a magnet stand. A supporting part for supporting a supporting plate is arranged at a position in the post and above the supporting part. A permanent magnet is placed above the supporting plate. The steel ball falls down in an arc shape from a standby height position when the permanent magnet is removed.

A tester for evaluating pullout load capacity and bond quality of anchor bolts embedded in concrete includes a Schmidt hammer for measuring a rebound number and an ultrasonic pulse velocity tester for measuring the transit time of a pulse transmitted through concrete surrounding an anchor bolt. The rebound number and the transit time are combined and matched against a database record which identifies the pullout load capacity and the bond quality. The transit time is matched to thresholds of transit times associated with porosity, internal cracking, air voids, and water pockets located around the embedded anchor bolt. The Schmidt hammer is further modified by the incorporation of a digital level for measuring the vertical and horizontal angles of inclination of the plunger with the concrete surface, a guide tube for supporting the plunger, and by using a convex plunger tip for improved registration with anchor bolt head.

A method for preparing a SiC ingot includes: disposing a raw material and a SiC seed crystal facing each other in a reactor having an internal space; subliming the raw material by controlling a temperature, a pressure, and an atmosphere of the internal space; growing the SiC ingot on the seed crystal; and collecting the SiC ingot after cooling the reactor. The wafer prepared from the ingot, which is prepared from the method, generates cracks when an impact is applied to a surface of the wafer, the impact is applied by an external impact source having mechanical energy, and a minimum value of the mechanical energy is 0.194 J to 0.475 J per unit area (cm.sup.2).

A system provided herein may be configured to evaluate helmet performance. The system may include an impact assembly that includes a stationary post operably coupled to one or more stationary load cells and a plurality of modular headforms. Each modular headform may include a first side and a second side configured to lock together around the impact assembly and receive a helmet. The modular headform may determine a position of the helmet relative to the one or more stationary load cells. Furthermore, the one or more stationary load cells may be configured to measure impact force at a position where one of the plurality of the modular headforms are operably coupled to the impact assembly. Additionally, each of the plurality of modular headforms correspond to a position in relation to the impact assembly to measure the impact force to the one or more load cells at a predefined number of impact locations on the helmet to evaluate the performance of the helmet.

An impact test method and an impact test device is provided, wherein an impact application member is caused to fall freely onto a test sample placed on a placement platform. When the impact application member collides with the test sample, an impact force applied to the test sample and an indentation amount of the impact application member with respect to the test sample are measured by a load meter and a displacement meter, respectively. Based on the measured impact force and the measured indentation amount, a calculation unit calculates energy loss absorbed by the test sample when the impact application member and the test sample collide with each other.

Apparatus and methods of evaluating brittleness by measuring force applied to an electrode specimen by simulating a wound state of a jelly-roll type electrode assembly are disclosed herein. In an embodiment, a brittleness evaluation apparatus includes a jig unit, a driving unit, and a measurement analyzing unit. The jig unit includes two jigs, a groove formed between the jigs, a pressing plate, and guides. The jigs facing each other and have top surfaces formed in a horizontal plane and configured to receive a specimen arranged on the top surfaces along a length direction extending between and along the top surfaces. The pressing plate is arranged perpendicular to the length direction and configured to cause the specimen to bend by descending into the groove. The guides are located on each of the top surfaces of the jigs and configured to prevent distortion of the specimen during descent of the pressing plate.