A borescope plug includes a threaded section that extends from a head section along an axis, the threaded section including a central passage along said axis. A spindle is located within the central passage. A multiple of detents are positioned in response to an axial position of the spindle along the axis.

A frost-prevention film system of a large-aperture reflecting optic infrared telescope used in an extremely low temperature environment and a preparation method thereof is disclosed. The frost-prevention film system has the following structure: a transparent conducting film layer, an intermediate insulation layer, a reflecting film layer and an outermost medium protection layer in sequence from a main telescope mirror surface, wherein both sides of the transparent conducting film layer are provided with conducting electrodes. The steps are as follows: (1) a preparation step; (2) a step of plating a conducting film; (3) a step of plating an intermediate insulation layer; (4) a step of plating a reflecting film layer; (5) a step of plating an outermost medium protection layer; and (6) a step of plating conducting electrodes.

An athermal compound lens includes a plano-concave lens and a plano-convex lens. The plano-concave lens has a first focal length, a first refractive index n.sub.1, and planar object-side surface opposite a concave image-side surface. The plano-convex lens is axially aligned with the plano-concave lens and has (i) a second focal length, (ii) a second refractive index n.sub.2, (iii) a planar image-side surface, and (iv) a convex object-side surface between the planar image-side surface and the concave image-side surface. In a free-space wavelength range and temperature range: (a) the first focal length divided by the second focal length is less than 0.68, and (b) first and second refractive indices n.sub.1 and n.sub.2 have respective temperature dependences

[00001]$\frac{.Math..Math.n_1}{.Math..Math.T}.Math..Math.\mathrm{and}.Math..Math.\frac{.Math..Math.n_2}{.Math..Math.T}$

that satisfy

[00002]$\left(\frac{.Math..Math.n_1}{.Math..Math.T}\right)/\left(\frac{.Math..Math.n_2}{.Math..Math.T}\right)2.$

An intrinsically safe video inspection system intended for use in a Class I, Zone 0 area is capable of visually surveying hazardous area locations; where the potential for fire or explosion exists because of gases, dust, or easily ignitable fibers in the atmosphere. The intrinsically safe camera of the present invention has the distinct ability to be used all areas that require increased safety and works in various hazardous environments, allowing users the ability to remotely view and inspect various mines, silos, and storage tanks. The inspection system includes a low power, high 3.2 megapixel resolution camera with digital zoom capability that allows for the close inspection and examination and utilizes an LED fiber light pipe for illumination needs. The video inspection system of the present invention provides for the illumination in various cavity sizes, while reducing the risk of unintended accidents.

An optically powered system for rapid, focused heating and melting of water ice. The optical wavelength is chosen to fall in a range where transmissivity through liquid water is higher than through ice. An alternative embodiment of the invention further comprises a length of fiber optic tether between source and output to allow for motion of the melt head. A further embodiment includes probing the ice using various sensing modalities exploiting the presence of the fiber in the ice, searching for biomarkers and characterizing the radiation/light environment for subsurface habitability, including photosynthetic potential and radiation environment as a source for energy.

A visual inspection posable invertebrate robot (VIPIR) borescope camera system can inspect components in difficult to reach locations. The system enables dexterous robotic inspection of worksites and areas that were heretofore impossible to inspect via extravehicular activities (EVA) and fixed situational awareness cameras. VIPIR may include: (1) a main drive assembly; (2) a reel system; (3) a video borescope assembly (VBA); (4) an enhanced motorized zoom lens (EMZL); (5) a fixed camera assembly (FCA); (6) a support structure; and/or (7) a main electronics box (MEB).

An imaging device includes: an optical element including a metal layer adapted to be brazed and arranged on an outer peripheral surface of the optical element; a first frame body including a metal part adapted to be brazed and arranged at least on an inner peripheral surface and an outer peripheral surface of the first frame body, the inner peripheral surface being brazed onto the outer peripheral surface of the optical element; and a second frame body including a metal part adapted to be brazed and arranged at least on an inner peripheral surface of the second frame body, the inner peripheral surface being brazed onto the outer peripheral surface of the first frame body. A coefficient of thermal expansion of the first frame body is closer to a coefficient of thermal expansion of the optical element than a coefficient of thermal expansion of the second frame body.

There is disclosed an access port for a casing of a gas turbine engine and a plug for plugging the access port. The access port and plug each include first and second baulking formations which are configured to engage with one another. The first and second baulking formations are spaced from one another by a unique angular separation which allows only the correct plug to be inserted into the correct access port.

An inspection tool for inspecting oil and/or gas production and/or injection wells and pipes is provided. The tool comprises at least an image sensor, one or more processors or chips and one or more power supplies. The tool further comprises at least a first and a second chamber being insulated from each other. The first chamber comprises the image sensor and is provided with one or more passive cooling means, and the second chamber comprises the one or more processors and is provided with one or more active cooling means. Further, a method for cooling such inspection tool is provided.

An endoscopy device (1) with an endoscope (2) and a camera control unit (12) is provided. The endoscope (2) has an endoscope shaft (3) and an endoscope head (4), and the endoscope shaft (3) is made of a metallic material. Electronics (8) are arranged in the endoscope head (4) and are connected to an attachment cable (10), and the electronics (8) and the attachment cable (10) are shielded by an electronics shield (14). A galvanic barrier (15) is set up between the electronics shield (14) and the endoscope shaft (3) and couples the endoscope shaft (3) capacitively to the electronics shield (14).