Abstract: A portable insulating device kit may be configured to fit within a smaller container for easier shipment. In one example, the assembly may include a base, a top wall having an opening, an inner liner configured to extend into the opening of the top wall to form an interior cavity defining a volumetric storage capacity and an exterior wall. The container can have a flat configuration defining a length, height, and width. The base, the top wall, the inner liner, and the exterior wall may be configured to be assembled into a portable insulating device. The volume of the container may be less than the volumetric storage capacity of the assembled portable insulating device, and the base, the inner liner, and the exterior wall are configured to be detached from one another and shipped in the container.

Abstract: An ice machine includes: an ice maker including: an ultrasonic bin sensor mounted to a body; and a controller in electrical communication with the ultrasonic bin sensor and configured to control the ultrasonic bin sensor; and a storage bin coupled to the ice maker and sized to receive a mound of ice, a lens of the ultrasonic bin sensor facing a bottom of an interior cavity of the storage bin, the controller configured to process a return signal of the ultrasonic bin sensor to control a level of ice stored inside the storage bin, the controller further configured to apply a predetermined time delay to filter out a portion of the return signal that exceeds a threshold voltage but does not exceed the time delay.

Abstract: Disclosed is a refrigerator. The present invention provides a refrigerator having a freezer compartment and a refrigerator compartment, the refrigerator including an icemaker provided to the freezer compartment or a freezer compartment door configured to open/close the freezer compartment, a dispenser provided to a refrigerator compartment door configured to open/close the refrigerator compartment, a water tank provided to the refrigerator compartment door, the water tank having an inlet for putting in water and an outlet for supplying water to the dispenser, a pump configured to send the water supplied from the water tank to the icemaker, and a slide cap movably provided to the water tank so as to be selectively coupled to a passage connected to the pump.

Abstract: A method for calculating a dry ice block necessary to preserve a product during transport, includes calculating a surface area:weight ratio needed for the dry ice block to preserve the product in at least one of a chilled condition and a frozen condition, and forming the dry ice block into a shape having said surface area:weight ratio. A related apparatus is also provided.

Abstract: Embodiments of the present disclosure include methods, apparatuses, and systems for cooling. Embodiments include a cooling system comprising a mobile container, conveyor system, and sensor feedback system. The container includes at least a first, second, and third section. First section holds at least one pallet containing produce. Second section includes a cooling mechanism to cool the produce within the at least one pallet to an optimal temperature. Third section includes the cooling mechanism to maintain the cooled produce in the at least one pallet at the optimal temperature. Conveyor system may be used to convey the at least one pallet across the cooling system. Sensor feedback system is configured to continuously measure and track at least the weight of the at least one pallet and temperature of the produce within the at least one pallet as the at least one pallet is conveyed across the cooling system.

Abstract: A method of refrigerator decorating that includes the steps of: placing a removable cover on at least one handle; and incorporating a decorative design in the removable cover. The removable cover preferably may include lighting or include glow in the dark features. The step of placing a removable cover on at least one handle includes placing a removable cover on a first handle and placing a removable cover on a second handle where the refrigerator includes two doors and two handles.

Abstract: A touch sensor assembly may include a touch substrate that is attached to a rear of a front panel on which touch points are displayed, a piezo disc in which a first pole and a second pole are stacked, wherein the first pole faces the touch substrate to contact a rear of the touch substrate; a holder that is configured to support a lateral surface and a rear of the piezo disc to fix the piezo disc to the rear of the touch substrate, and a cover that has a front surface which adheres to the rear of the touch substrate and that includes a concave chamber which is overlapped with the holder. A refrigerator door may include the touch sensor assembly.

Abstract: A throat assembly (14) for forming the peripheral front face of the compartment opening of a refrigeration appliance (1). The throat assembly spanning the gap between respective front edges of a refrigerator cabinet (3) outer wrapper (2) and the compartment inner liner (13). The throat assembly includes at least one elongate plastics injection moulded component having a panel (15) including a planar front face (21) for contact with a door gasket seal (16) and an elongate magnet arrangement at its rear face (22) for magnetic coupling with a door gasket magnet (20). The throat assembly may comprise plural such interconnected elongate members providing a monolithic frame, formed in a single injection moulding operation, surrounding the compartment opening.

Abstract: A refrigerator may be installed in a storage space defined by a wall of an object and includes a contact mechanism to bring the refrigerator into contact with the wall.

Abstract: A bin positioned within a refrigerator drawer and slidable across the refrigerator drawer at one or more edges of the refrigerator drawer and/or at one or more sliding mechanisms attached to at least one side of the refrigerator drawer.

Abstract: Provided is a method of setting a system, the method being performed by a processor and including: (a) when receiving detection, by the sensor, of a first amount of goods equal to or larger than a first predetermined amount, displaying, on a display, a first screen prompting setting of a threshold amount of goods corresponding to a condition of trigger output; (b) when the sensor detects reduction of an amount of goods by at least a second predetermined amount after displaying the first screen, acquiring, as the threshold amount, a second amount of reduced goods; (c) after the threshold amount is acquired, displaying, on the display, a second screen for setting an action of the processing device; and (d) based on information on the action set after displaying the second screen, setting output contents to be output by the processing device upon satisfaction of the condition of trigger output.

Abstract: An artificial intelligence refrigerator includes a communication unit, a camera configured to capture an image of a tray including a plurality of grooves for storing food, and a processor configured to control the communication unit and the camera. The processor extracts a marker hidden by the food of a plurality of markers respectively attached to the plurality of grooves from the captured image of the tray, acquires a position identifier of a groove corresponding to the hidden marker and a reception time indicating that the food is received in the groove, transmits the acquired position identifier and the reception time to a server through the communication unit, receives determined color information from the server based on the reception time, and controls a light emitting element provided in the groove to output a color to be displayed on the groove included in the received color information.

Abstract: A device for refrigerating and/or liquefying a working gas comprising helium, the device comprising a looped working circuit for the working gas includes, in series, a compression station, a cold box, a heat exchange system exchanging heat between the cooled working gas and a user, the device further comprising an additional pre-cooling system comprising at least one tank of auxiliary cryogenic fluid, such as liquid nitrogen, the cold box comprising a first cooling stage of the working gas comprising a first exchanger disposed at the output of the compression station as well as a second heat exchanger and a third heat exchanger, the first heat exchanger being of the aluminum plate-fin type, the second heat exchanger being of the tube or welded plate type, characterized in that the second and third heat exchangers are connected both serially and in parallel on the working circuit downstream of the first heat exchanger.

Abstract: A module for a natural gas liquefaction apparatus is provided to include air-cooled heat exchanger groups and another equipment group. The air-cooled heat exchanger groups another equipment group. The air-cooled heat exchanger groups are arranged side by side on an upper surface of a structure, and are each configured to cool a fluid handled in the natural gas liquefaction apparatus. The another equipment group is arranged on a lower side from an arrangement height of each air-cooled heat exchanger groups, and forms a part of the natural gas liquefaction apparatus.

Abstract: A split mixed refrigerant (“MR”) natural gas liquefication system, where low-pressure (“LP”) and medium pressure (“MP”) MR compressors are driven by a first gas turbine and a propane compressor and a high-pressure (“HP”) MR compressor is driven by a second gas turbine, is disclosed. The split MR liquefication system is configured to adjust the characteristics of the HP MR compressor to require less power when less power is available and more power when more power is available compared to the system's design point. Such adjustments allow for shifting the balance of power between the propane compressor and the HP MR compressor to improve LNG production efficiency.

Abstract: Plant for the production of argon by cryogenic distillation, comprising an argon separation column, means for sending a gas containing argon and oxygen to the argon separation column, means for extracting a fluid enriched in argon at the top of the argon separation column, means for extracting a liquid enriched in oxygen at the bottom of the argon separation column and at least two storage tanks, positioned one above the other, each storage tank being connected to two different intermediate levels of the argon separation column by two pipes, the two storage tanks being contiguous.

Abstract: A temperature control device for surface-treated objects such as vehicle parts, having a temperature control chamber, in which a surface-treated object can be temperature-controlled, a high-boiler exhaust air flow having high-boiling organic compounds from the temperature control chamber, and a combustion unit for the thermal aftertreatment of the high-boiler exhaust air flow. A device for the pyrolysis of the high-boiler exhaust air flow is also provided. A method for controlling the temperature of a surface-treated object having such a temperature control device is also provided.

Abstract: A sealed feeder device utilized in an electric arc furnace (1), and a flue gas and temperature control method. The sealed feeder device comprises a sealed feeding chute (5) having an outlet sealedly communicating with a side wall of the electric arc furnace (1), and a material blocking sealed arc-shaped door (3) disposed in the sealed feeding chute (5). The material blocking sealed arc-shaped door (3) separates the sealed feeding chute (5) into a cold steel scrap storage chamber (18) and a material feeding and dedusting chamber (2), and is operated by a driving mechanism (34) to separate or connect the cold steel scrap storage chamber (18) and the material feeding and dedusting chamber (2).

Abstract: A side wall of a pallet car for a travelling grate machine including an upright portion, a wing portion and a lower connection flange, where the wing portion has an upper surface acting as an extension of a loading surface of the pallet car, the upper surface of the wing portion being arranged at an angle with respect to the horizontal.

Abstract: A system measures parameters of the electricity drawn by an arc furnace and, based on an analysis of the parameters, provides indicators of whether arc coverage has been optimized. Factors related to optimization of arc coverage include electrode position, charge level, slag level and slag behaviour. More specifically, such indicators of whether arc coverage has been optimized may be used when determining a position for the electrode such that, to an extent possible, a stable arc cavity is maintained and an open arc condition is avoided. Conveniently, by avoiding open arc conditions, the internal linings of the furnace walls and roof may be protected from excessive wear and tear.

Abstract: Heat exchanger assemblies for electronic devices are disclosed. A heat exchanger assembly may include a heat transfer body that has a face that forms open passageways. A cover structure may be attached to the heat transfer body in a manner to enclose the open passageways, thereby forming a heat exchanger assembly that includes enclosed fluid conduits. In this regard, the enclosed fluid conduits may form complex and intricate patterns within the heat exchanger assembly that are tailored to the heat requirements of a particular application. Heat exchanger assemblies as described herein may be thermally coupled to a center waveguide section of a spatial power-combining device. The enclosed fluid conduits may be tailored based on locations of amplifiers within the center waveguide section to provide improved thermal operation of the spatial power-combining device.

Abstract: Heat exchanger assemblies for electronic devices and related methods are disclosed. A heat exchanger assembly may include a heat transfer body that has a face that forms open passageways, and a cover structure attached to the heat transfer body that encloses the open passageways, thereby forming enclosed fluid conduits. Heat exchanger assemblies as described herein may be thermally coupled to a center waveguide section of a spatial power-combining device. Related methods include forming open passageways by selectively removing material from a face of a heat transfer body. Multiple heat transfer bodies may be formed simultaneously by forming multiple groups or patterns of open passageways across a larger area of a heat transfer body material, and subsequently singulating the heat transfer body material into multiple heat transfer bodies. Cover structures as previously described may be formed on the heat transfer bodies before or after singulation.

Abstract: Embodiments described herein relate to a heat exchanger for abating compounds produced in semiconductor processes. When hot effluent flows into the heat exchanger, a coolant can be flowed to walls of a heat exchanging surface within the heat exchanger. The heat exchanging surface can be a curved shaped which creates a multi stage cross flow path for the hot effluent to flow down the heat exchanger. This flow path forces the hot effluent to hit the cold walls of the heat exchanging surface, significantly cooling the effluent and preventing it from flowing directly into the vacuum pumps and causing heat damage. Embodiments described herein also relate to methods of forming a heat exchanger. The heat exchanger can be created by sequentially depositing layers of thermally conductive material on surfaces using 3-D printing, creating a much smaller foot print and reducing costs.

Abstract: A counter-flow heat exchanger including: a primary flow passageway comprising a primary flow inlet, a primary flow outlet, and a plurality of primary flow subset passageways therebetween; a secondary flow passageway comprising a secondary flow inlet, a secondary flow outlet, and a plurality of secondary flow subset passageways therebetween; and a heat exchanger core comprising portions of the plurality of primary flow subset passageways and the plurality of secondary flow subset passageways, the secondary flow passageway being in thermal communication with the primary flow passageway in the heat exchanger core, wherein the primary flow subset passageways in the heat exchanger core and the secondary flow subset passageways in the heat exchanger core are oriented such that primary fluid flow through the primary flow subset passageways flows opposite secondary fluid flow through the secondary flow subset passageways.

Abstract: A flat-plate heat pipe structure includes a main body. The main body has a first board body, a second board body, a first capillary structure and a working fluid. The first and second board bodies are overlapped and mated with each other. The first capillary structure is disposed between the first and second board bodies. The first capillary structure and the first and second board bodies together define at least one vapor passage. Accordingly, when the flat-plate heat pipe is thinned, the flat-plate heat pipe still keeps having a vapor passage, whereby the vapor-liquid circulation efficiency of the flat-plate heat pipe will not be deteriorated due to thinning.

Abstract: The device and methods described herein relate to the isothermal heat transport through an intermittent liquid supply to an evaporator device, thereby enabling high evaporative heat transfer coefficients. A liquid and vapor mixture flows through miniature and micro-channels in an evaporator and addresses flow instabilities encountered in these channels as bubbles rapidly expand. Additionally, a high percentage of the fins are exposed to vapor and limit the required charge of refrigerant t within the system due to effective condensate removal in the condenser.

Abstract: Provided is a heat pipe which is installed in a cold region in a bottom heat posture in which a longitudinal direction of a container is substantially in parallel with a gravitational direction, is capable of preventing the container from deforming even when a working fluid has become frozen, and has excellent heat transport properties.

Abstract: The invention provides a method for reclaiming heat from a fluid, the method having the steps of contacting the fluid to a phase change material for a time sufficient to increase the temperature of the material and or liquefy some of it; and contacting the material to a second fluid for a time sufficient to increase the temperature of the second fluid and to decrease the temperature of the material or to solidify some of it.

Abstract: Vibration absorption tubing and a manufacturing method thereof. The manufacturing method includes: a solder placement step including: placing solder at solder placement portions in an inner cavity of an adaptor; a pipe fitting step including: fitting a corrugated pipe and the adaptor respectively to adaptor matching portions at corresponding sides of the adaptor, to communicate an adaptor inner cavity with an inner cavity of the corrugated pipe and inner cavities of external connection tubing; and fixing or limiting positions of the corrugated pipe, the adaptor, and the external connection tubing to obtain a tubing assembly; and a component brazing step including: performing furnace brazing on the tubing assembly of the external connection tubing to obtain a main vibration absorption tubing. The vibration absorption tubing has favorable brazing consistency, enhancing connection reliability of components.

Abstract: A plate heat exchanger causes heat exchange to be performed using a plurality of heat transfer plates stacked. Each of the heat transfer plates includes a plate body, a first-medium inlet, a first-medium outlet, a second-medium inlet, a second-medium outlet, and a projection that provides a passage. At least one of the first-medium inlet and the first-medium outlet is located at one of two corners at one end of the plate body which the projection contacts. At least one of the second-medium inlet and the second-medium outlet is located at one of two corners at the other end of the plate body from which the projection is separated.

Abstract: A method and assembly for conveying heat from a heat exchanger having a housing defining a fluid pathway including at least one fluid passageway leading from an inlet port of the heat exchanger to an outlet port of the heat exchanger, the housing have a first side and a second side, opposite the first side where the housing includes at least one aperture extending through the housing from the first side to the second side and where the aperture is fluidly separate from the fluid pathway and heat from liquid flowing through the fluid pathway is transferred via at least one of conduction or convection to the housing.

Abstract: A method for cleaning, sanitizing, and disinfecting commercial and residential HVAC system includes applying low pressure cleaning foam to heat-exchange coils of the HVAC system, the cleaning foam including one or more agents that break down organic and/or inorganic fouling dirt or debris, the foam removing and carrying away dirt or debris from the coils. Moving air, such as from the air handler of the HVAC system, pushes or draws the cleaning foam from the first side of the coils toward a second side, the cleaning foam and removed dirt or debris exiting the second side of the coils. The moving air and cleaning foam move co-currently in the same direction through spaces in the coils.

Abstract: A high capacity handgun/pistol is disclosed with a horizontally oriented magazine that is aligned with and disposed beneath the gun barrel. The magazine defines a plurality of hollow tubes arranged radially around a central axis about which the magazine can rotate automatically during operation of the handgun/pistol. The hollow tubes each contain a plurality of ammunition rounds, and can each be aligned with a loading tray one at a time, wherein a coil spring will push out a single round at a time onto the loading tray. The handgun uses a gun slide to load a new round into the chamber via the loading tray, and further enabling the loading tray to automatically rotate the magazine as each hollow tube becomes empty. Moreover, the slide will re-set a hammer to re-engage with a sear, after a pulled trigger releases the hammer to strike a firing pin.

Abstract: A trigger mechanism for a firearm which has a light trigger pull, reliably contains the high forces of the firing pin spring and achieves this with a mechanism which is simple and with few parts. A toggle linkage prevents the firing pin retainer releasing the firing pin whilst still allowing a light pull. It contains no internal sear and no pins within the toggle mechanism. It is adjustable for variations in manufacturing and can cater for various levels of trigger pull force. It realizes considerable economies for production, assembly and repair without sacrificing functionality.

Abstract: A corner shot firearm comprises one or more clamp, a trigger actuator, a front grip, an accessory trigger, a pivot stud and an aim control wheel. The clamp includes a first mounting point disposed at a front end of the clamp, wherein the first mounting point is configured to mount a secondary firearm. Additionally, the trigger actuator is connected to the first mounting point. The front grip is attached to a rear end of the clamp. The accessory trigger is connected to the front grip such that the accessory trigger is actuatable by a finger of the human hand holding the front grip. Additionally, the pivot stud is connected to the first mounting point. Further, the aim control wheel is connected to the first mounting point.

Abstract: A universal percussion trigger mechanism, comprising a trigger housing (22) with a magazine (1), safety catch (3), magazine latch (7), firing pin (8), trigger bar (23), spring (12) of the trigger bar, universal percussion mechanism (38), which is fixed in the receiver (20), and consists of a bracket for universal percussion mechanism (16), cocking piece (17) with a cocking indicator mounted on the axis of the cocking piece (18) and spiral mainsprings (19), sear (11) and a single-shot sear (27).

Abstract: A tapered arrow launcher is disclosed as it may be implemented with an arrow launch platform (or arrow rest) for an archery bow. An example tapered arrow rest launcher may include an arrow support end, and a mounting end. The arrow support end of the arrow rest launcher is thinner than the mounting end, resulting in a thickness that is tapered along one or more sections. With this arrangement, fatigue forces and work hardening forces do not concentrate at the mounting end of the tapered arrow launcher when arrows are launched with the arrow launch platform.

Abstract: The invention relates to a weapon front handle, the handle extending along a given axis and comprising a plate for securing to a weapon and a grip for gripping the handle, which grip is connected to the plate and shaped to present grooves for receiving a user's fingers, the handle wherein the grip is connected to the plate in such a manner as to be mounted to pivot relative to the plate about the given axis, the handle including at least one latch for temporarily blocking pivoting of the grip relative to the date about the given axis. The invention also relates to a weapon including such a front handle.

Abstract: A rifle sling is provided for use with a shooting adapter for a firearm. The rifle sling comprises a first portion having a forward end including a first attachment facility configured for attachment to a forward portion of a rifle, and a second portion having a rear end including a second attachment facility configured for attachment to a rear portion of a rifle. Further, a connector is configured to removable connect the first and second portion, the connector includes three parallel bars collectively defining two elongated slots. One of the slots has a lateral opening at a slots end, the opening is configured to removably retain a strap and to permit removal and insertion of an intermediate portion of the strap.

Abstract: The invention relates to a long-range optical device, in particular telescopic sight, comprising a reticle, the position of which can be adjusted, and comprising an associated mechanism for adjusting the reticle, comprising a first magnetic element in the form of a ring magnet, a second magnetic element in the form of a bar magnet, motion-coupled to the reticle and movably mounted relative to the first magnetic element, wherein a variable magnetic characteristic value is formed as a function of the relative position between the first and the second magnetic element, a detection unit, which is configured to detect a change in the magnetic characteristic value formed in the first or second magnetic element, a determination unit to determine reticle position information describing the position of the reticle based on a magnetic characteristic value of the first and/or second magnetic element.

Abstract: A device includes a land drone and a control center for controlling the land drone. The land drone includes a mobile base, a support arm, and a head including at least one means for acting and connected to the support arm. The head can be attached to a base assembly and support arm of a platform lift of a military vehicle and converted into a drone. The adaptability of a head on various types of platform lifts allows a land drone to be rapidly deployed in a hostile environment. The choice of means for acting makes it possible to confront various types of risk situations. In particular, the device may be deployed in a military context, for example, urban combat, in which the base of the drone is a military vehicle, for example, a tank. A method for implementing a device is also provided.

Abstract: A method of making and deploying a bullet proof vest that can be used to protect students at points of education. The method involves a process of combining/bonding fifteen fiberglass sheets with fiberglass resin in a time specific manner and then pressing the fiberglass sheets together thereby forming a fiberglass plate. A pair of fiberglass plates formed using the present method are thereafter inserted within a vest that has a front and a back receiving pocket. The vest has a strap that is used to tighten the vest on a user wearing the vest. The bullet proof vest of the present invention is inexpensive, lightweight and may also include a tracking device that will inform the authorities of the deployment of the vest. The tracking device of the bullet proof vest will connect to a central monitoring system and will be stored/deployed within an educational desk.

Abstract: The present application provides a full-coverage bulletproof backpack, which comprises: a backpack body, a double-shoulder strap, a first sandwich, and a second sandwich, wherein the double-shoulder strap is fixedly provided on the back side of the backpack body, and the first sandwich and the second sandwich are provided in the backpack body, wherein the first sandwich is fixedly provided with a first bulletproof part, and the second sandwich is provided with a second bulletproof part, the second sandwich is provided with a pulling structure, the upper side of the double-shoulder strap is provided with an upper fixing part, and the lower side thereof is provided with a lower fixing part.

Abstract: A removable ballistic desk top is mated to a desk frame and can be removed in the event of an active shooter situation. The desk top has a top layer, a fabric layer, and a bottom layer. The fabric layer is a woven mesh and is bonded between the top and bottom layer. The desk top has a beveled edge that provides additional deflection of any projectiles when the beveled edge is placed near the floor. The desk top further includes handles and releasable latches for easy removal and installation to the desk frame.

Abstract: A ballistic resistant article includes a first layer that has first unidirectional fibers disposed in a first polymer matrix. The first polymer matrix is composed of a thermoset polyurethane. A second layer is laminated to the first layer. The second layer includes second unidirectional fibers disposed in a second polymer matrix. The second unidirectional fibers are cross-oriented with respect to the first unidirectional fibers.

Abstract: The subject disclosure relates an aerial system to track a detected obstacle. The aerial system may comprise a plurality of aircraft, an aircraft storage system to house the plurality of aircraft, an aircraft controller in communication with each of a tracking system and the plurality of aircraft. In operation, one or more of the plurality of aircraft may engage the detected threat. At least one of the plurality of aircraft may include a target neutralization device to strike the detected threat.

Abstract: A projectile target 10 comprises a support structure 20 adapted to support two or more targets 30. The targets 30 are ideally off the ground 12, that is spaced from the ground 12. Each target 30 is, in turn, supported by an arm 32 extending from a common hinge 34. Each pair of targets 30 includes a first main target 30a and a second target 30b. In a first position 38a, the first target 30a presents a first broad target surface 36a to an operator or shooter (not shown). The second target 30b is displaced so that it does not present a viable target to the operator. However, the second target 30b is adapted to move into a second, viable, target position 38b when the first target 30a is struck substantially on its broad target surface 36a by a projectile, such as a .22 calibre bullet.

Abstract: A method where a laser beam is configured to generate a laser-induced plasma filament (LIPF), and the LIPF acts as a decoy to detract a homing missile or other threat from a specific target.

Abstract: The invention relates to dartboard games, where projectiles are thrown at a target. The face of the dartboard has a realistic, lifelike image of a game animal, and the higher scoring regions correlate to the kill zone of the game animal's anatomy. Lower scoring regions correlate to the rest of the body of the game animal, and penalty scoring regions may be present, scoring negative points. Players try to land their darts in certain scoring regions in order to score the most points, depending upon the rules of the game. Rules are provided for a 300 point and 21 point game. If the images are printed on the dartboard, the darts may be thrown or launched with an apparatus like a mini-bow or blow-gun. If the images are projected, the darts may be virtual.

Abstract: The present invention relates to a device, a system and a method for retaining detonators in an explosive booster, particularly a retention device for retaining a detonator in the blind hole of a booster which allows the safe extraction thereof from the booster. The retention device comprises a flexible holding means that is movable between a blocking position retaining the detonator inside the blind hole and an open position which allows extracting the detonator from the blind hole.