Abstract: An in-situ stress measurement method is provided. The method includes measuring a length of a maximum diameter at which an amount of distortion relative to a diameter of a standard circle of a measurement cross section of a boring core is largest and a length of a minimum diameter at which the amount of distortion relative to the diameter of the standard circle is smallest based on a shape of the measurement cross section of the boring core; measuring a length of a diameter in a vertical direction and a length of a diameter in a horizontal direction of the measurement cross section of a side-wall core acquired by hollowing ground in a well in an excavation direction thereof, based on a shape of the measurement cross section of the side-wall core; and calculating a maximum horizontal stress and a minimum horizontal stress by first and second equations.

Abstract: An in-situ stress measurement method is provided. The method includes measuring a length of a maximum diameter at which an amount of distortion relative to a diameter of a standard circle of a measurement cross section of a boring core is largest and a length of a minimum diameter at which the amount of distortion relative to the diameter of the standard circle is smallest based on a shape of the measurement cross section of the boring core; measuring a length of a diameter in a vertical direction and a length of a diameter in a horizontal direction of the measurement cross section of a side-wall core acquired by hollowing ground in a well in an excavation direction thereof, based on a shape of the measurement cross section of the side-wall core; and calculating a maximum horizontal stress and a minimum horizontal stress by first and second equations.

Abstract: To fill a cable connection head with an insulating oil and provide a movable lid member of the oil to ensure a long-term insulating property in the cable connection head and enable long-term continuous use of a measuring device. A cable connection head 18 having a head body 21 comprised of a bottom head body 19 and a top head body 20 connected to a measuring device body 6, having a well logging cable 1 passed through the top head body 30, and having core conductors of sheathed cables 2 connected to a connector 11 fit into the bottom head body 19, wherein the bottom head body 19 is filled with a low viscosity insulating oil 29 with a specific gravity heavier than the borehole fluid, outflow of the low viscosity insulating oil 29 is prevented, and a movable sealing member 30 preventing entry of borehole fluid is provided movably inside the bottom head body 19.

Abstract: [PROBLEM] To fill a cable connection head with an insulating oil and provide a movable lid member of the oil to ensure a long-term insulating property in the cable connection head and enable long-term continuous use of a measuring device. [MEANS FOR SOLUTION] A cable connection head 18 having a head body 21 comprised of a bottom head body 19 and a top head body 20 connected to a measuring device body 6, having a well logging cable 1 passed through the top head body 30, and having core conductors of sheathed cables 2 connected to a connector 11 fit into the bottom head body 19, wherein the bottom head body 19 is filled with a low viscosity insulating oil 29 with a specific gravity heavier than the borehole fluid, outflow of the low viscosity insulating oil 29 is prevented, and a movable sealing member 30 preventing entry of borehole fluid is provided movably inside the bottom head body 19.

Abstract: An image forming apparatus provided with an image forming part capable of reproducing on a recording medium an image information frame recorded on a microfilm. The apparatus effects a decision as to whether or not image information is present within the range of a prescribed width inwardly of the edge of the image information frame. When the presence of the image information in the range mentioned above is discerned, the part of the projected light reaching the image forming part which falls outside the edge is intercepted and the image information within the image information frame is completely reproduced on the recording medium. When the absence of the image information in the aforementioned range is confirmed, the part of the projected light which falls outside the edge and within the range of the prescribed width inwardly of the edge is intercepted so that the background part of the negative film is not reproduced on the recording medium.

Abstract: A reader-printer with an image size judging function, which has a plurality of sensors for judging a size of a desired image retrieved out of a multiplicity of images recorded on a microfilm. These sensors are arranged along a film transport direction to allow them to have a predetermined detection area.