A rifle bow assembly is disclosed herein. The rifle bow assembly includes: an outer barrel slide subassembly having an elongate cavity, the outer barrel slide subassembly configured to be attached to a bow assembly; a projectile barrel subassembly having a first end and a second end, the projectile barrel subassembly configured to be slidingly received within the elongate cavity of the outer barrel slide subassembly, and the projectile barrel subassembly having a helical projectile passageway extending in a lengthwise direction thereof; a magazine subassembly coupled to the second end of the projectile barrel subassembly, and having attachment means for securing a projectile magazine thereto; and a release subassembly coupled to an end portion of the magazine subassembly, the release subassembly including at least one string release mechanism for releasably engaging a bow string of the bow assembly. A rifle bow, which incorporates the rifle bow assembly, is also disclosed herein.

In at least one embodiment, a crossbow comprises a stock, a first limb, a first rotatable member, a second limb and a second rotatable member. A bowstring, a first cable and a second cable each extend between the first rotatable member and the second rotatable member. The crossbow defines a shooting axis. The first cable is offset from the shooting axis in a first direction and the second cable is offset from the shooting axis in a second direction different from the first direction.

In some embodiments, a connector attaches to an axle of an archery bow and comprises a cable terminal. The connector comprises a first body portion made from a first material and a second body portion made from a second material different from the first material. The first body portion defines an aperture therethrough arranged to engage the axle. The second body portion has a groove extending around at least a portion of its periphery, forming a teardrop shape. In some embodiments, the connector is configured to snap-fit onto an axle and be removable without tools.

This invention belongs to the group of projectile throwing instruments working without an explosive or a combustible propelling charge in particular to the group of projectile throwing instruments using strained hard body energy and can be used for the design and construction of a missile throwing weapon using a string—namely a bow and crossbow.

An archery bowstring release has a single jaw for retaining a bowstring within a bowstring hook, in contrast to dual-jaw pincer-type releases. The bowstring hook is situated on a release head which bears a trigger for actuating the jaw and releasing the bowstring, and a release body extends between the release head and a release mount (which can connect the bowstring release to a wrist strap, glove, or other anchor affixed to the user's body). The release head and body are pivotally joined, and when the release is ready to fire, the central axis of the release body, and at least the rear of the release head, have central longitudinal axes which are aligned with the notch in the bowstring hook, and are thus aligned with the bowstring, and are parallel to or in line with the arrow. The release therefore has a comfortable, natural, and intuitive feel during operation.

An archery bow is comprised of at least a riser and two limbs that can be folded into a position forming its own case to protect the limbs, or taken down and reassembled with limbs of various draw weights. When taken down it may also be reconfigured to enable use by an archer with opposite handedness. In its folded state it is highly compact and transportable.

A crossbow 100 includes a rifle-style stock 22, barrel 23, bowstring 1, and a string release housing 21 with a novel string release assembly. The string release assembly in string release housing 21 includes a string latch 12 for retaining fully-drawn and cocked bowstring 1 against a string horn 19, a trigger 6 for releasing or shooting the arrow 2, a safety button 25 for the movement of the safety plate 7 from the safe position to the fire position, and a load lever 4 for loading the arrow 2. There is a safety button 25 on each side of the release housing 21 so that the safety of crossbow 100 may be operated by a right-handed or left-handed shooter. Bowstring 1 rests against the inclined surface 29 of the string horn 19 and is retained in the fully-drawn and cocked position between the string latch tangs 30 and 31 and the inclined surface 29 of the string horn 19. The load of the fully-drawn bowstring 1 is distributed between and born by the inclined the string latch tangs 30 and 31 and the inclined surface 29 of string horn 19.

An arrow rest for supporting an arrow on an archery bow. In various embodiments, the arrow rest includes an over-center spring that is operatively coupled to a body of the arrow rest and a rotatable cam received in the arrow rest body. The rotatable cam is rotationally fixed to an arrow launcher. The over-center spring biases the arrow launcher into a first loading position when the spring is in a first position on one side of a central axis about which the cam rotates, and into a second launching position when the spring moves to an opposite side of the cam central axis. A release mechanism is configured to move the arrow launcher from the second, launching position to the first, loading position when an arrow is fired from the bow, but will not move the arrow launcher to the first, loading position if the bow is let down.

A sight and range finder for a projectile launching device are disclosed. The range finder calculates a range between a target and a projectile launching device, and transmits a signal indicative of the range. The sight visually aligns the target with the projectile launching device. A drive assembly moves an alignment member of the sight, and at least one processor receives the signal and actuates the drive assembly to move the alignment portion a selected distance based on the range.

A trigger assembly for a crossbow comprises a string retainer and a trigger mechanism. The trigger assembly can further comprise a piston, a safety mechanism, a secondary safety mechanism, a bolt sensor, or a pair of rotating sears. The string retainer can comprise a pair of opposed jaws.

A ball throwing machine can include a hopper for receiving one or more balls and a ball delivery device. The ball delivery device can be used to throw or pitch a ball from the hopper to a user of the machine. The ball delivery device can include wheels to impart speed to the ball and a direction system to control the projection angle of the ball. The direction system can control at least one of the up and down angle and the side to side angle of the ball as it is thrown, among possibly other throwing parameters. A controller may be provided for controlling operation of the ball throwing machine.

In some embodiments, a crossbow comprises a stock and a bow portion comprising at least one limb and a string. A riser attaches said bow portion to the stock. A latch is located in proximity to a butt of the stock. The latch is configured to retain the string in a drawn condition. A trigger is arranged to release the latch. An extension member extends from the butt of the stock to the latch. The extension member and the stock define a cavity, and the latch assembly is oriented within the cavity.

A football passing machine is configured to eject a prolate-spheroid-shaped football. The football passing machine includes a frame member, an adjustable launch surface mounted to the frame member, a ball magazine positioned above the adjustable launch surface that is configured to contain a plurality of footballs, a moveable escapement arm that is configured to successively dispense footballs that are contained within the ball magazine onto the launch surface, a moveable ball carriage configured to move a football between a first point on the launch surface that is located directly beneath the ball magazine and a second point on the launch surface that is adjacent a football launch mechanism that is configured to eject a football from the football passing machine. An orientation of the adjustable launch surface is configured to be adjusted to change a launch angle of a football while the frame member and the ball magazine remain stationary.

A bowstring release having a removable safety pin that when engaged, allows for training. The safety pin physically preventing the release mechanism from fully releasing, while allowing enough movement to provide a tactile response that the release has been activated.

A universal wrist strap, for connection to a plurality of different bowstring release mechanisms via a plurality of different connecting members, includes a flexible base member adapted to fit around the wrist of a user and a mounting assembly connected to the wrist strap. The flexible base member has first and second arms that converge towards an apex area. The mounting assembly is connected to the apex area and is adapted to receive and retain the plurality of different connecting members.

Arrow rest arrangements according to certain embodiments include an elongate arm mounted to extend into and rotate in the plane of an arrow aligned with an archery bow and riser. The arm can rotate from an open position, for example where the arm is substantially perpendicular to the arrow shaft, to a closed position where the arm engages and may be substantially aligned with the arrow shaft. The arm preferably includes two opposing end portions to engage, constrain and align the arrow shaft in the closed position, yet which drop or rotate away from the shaft upon release of the arrow to allow the arrow to freely leave the bow.

The apparatus for mounting at least one dampener and/or stabilizer to an archery bow to absorb shock and vibration realized by an archer upon the release of the archery bow. The present invention provides an elongated support structure releasably connectable to the at least one dampener and/or stabilizer. A releasable fastener is connected to one end of the support structure, and the releasable fastener is releasably connectable to the archery bow such that the support structure is extendible in a cantilevered position relative to the archery bow.

An archery bow vibration dampening and balancing device is attachable to an archery bow by means of an elongated clamp with a housing pivotably interconnected to the elongated clamp opposite the attachment point. A vibration dampening and balancing device is secured in an opening formed in the housing.

An archery stabilizer which, by utilizing a carbon fiber tube or a comparable material in a tube configuration, provides for preloading the tube in compression, thereby effectively increasing the stiffness of the tube. The stabilizer includes weights, and the preloading of the tube compensates for the bending moment applied to the tube by the weights attached to the end of the tube or contained within the tube. In effect, the present invention presents an apparatus and method for loading the tube so as to allow a user to adjust the elastic modulus of the tube.

A vibration dampened barrel for a crossbow preferably includes at least two vibration dampening chambers, which extend at least a portion of a length of the vibration dampened barrel. The at least two vibration dampening chambers are at least partially filled with a vibration dampening material, such as silicone, rubber, low density foam, high density foam, or any other suitable material that absorbs noise and or vibration. The vibration dampening material is preferably applied by injection, compression, spray, pouring or any other suitable method. The vibration dampening material is retained in the at least two vibration dampening chambers by curing or hardening; mechanically confinement including the use of fasteners or a plug; or with any other suitable method. The at least two vibration dampening chambers may be partially or fully filled. The vibration dampening material may also be placed on a surface inside an extruded barrel.

A manually directed lathe tool system for removal of internally disposed material and creating a void inside a lathe turned form. As shown in FIG. 1, an articulated boring bar (32) of a tubular crosssection is slidably manipulated and supported by a plane surface (140) during a cutting action. To increase offset cutting ability several different lengths of a detachable and hinged arm assembly (40) are used. Arm assembly can be fixed or moved to three different positions relative to boring bar (FIG. 2) by manipulating a hand knob (36). A moveable and replaceable cutting tool (198) is held at the end of the arm assembly. A wall thickness caliper system (44) which ends in a tip (130) of some flexible material to allow operator appraisal of the internally disposed cutting tool's position. A back restraint assembly (141) is used to prevent the downward pitch of the boring bar's cutting end during material removal and consequent upward pitch of the opposite end of the boring bar, and especially during a highly leveraged cutting action. An outrider (38) attached to the boring bar prevents rotational movement of the tool relative to its longitudinal axis, especially during a leveraged offset cutting action. The outrider is able to be attached at several different locations on the boring bar and also serves as the support for the caliper system. Platform base (34B) is mounted rigidly to the lathe bed (30) and maintains platform assembly (34A) at a proper height. A precise wall thickness that mirrors the outside form can be achieved with this system. The system can be used to hollow-out forms not possible with previous practice. A narrow and restricted mouth opening does not hinder hollowing-out large diameters and deep forms. The operator is in control during all leveraged cutting actions and experiences minimal operator fatigue.

A dowel maker having a first rough-sizing blade attached to a body with a micro-adjust assembly for adjusting blade position and a second finish-cutting blade also attached to a body with a micro-adjust assembly for adjusting blade position. Dowel diameters smaller than the largest diameter the body can accommodate may be produced using interchangeable front insert guides, and interchangeable rear guides are also used for different diameter dowels. A workpiece with a square cross-section end is driven through the dowel maker with a square recess socket driven by an electric hand drill.

A cutting tool piece is provided including a rear portion and a lead portion, the lead portion including a front section having an upper side angled downwardly and forwardly and a lower side angled upwardly and forwardly to form a transverse lead cutting edge. The rear portion includes a hole to secure the tool piece to a cutting tool and transverse cutting edges extending outwardly from side walls of the front section. A system is also described for cutting a bowl by coring out an interior portion of a wood block by applying the cutting tool which is curved and rotatably mounted to a post. Its lead end with the tool piece attached creates a circular groove. The cutting tool is advanced on a path which curves toward the central axis of the lathe.

A hollowing system for a lathe having a tool rest. The hollowing system comprises a boring member, and a stabilization assembly. The boring member is adapted to support a tool such that at least one of the boring member and the tool extend past and engage the tool rest. The stabilization assembly is mountable adjacent to the lathe. The stabilization assembly supports the boring member such that the boring member extends generally parallel to a longitudinal axis of the lathe. The stabilization assembly has a vertical axis and a horizontal axis. The stabilization assembly is adapted to prevent downward movement of the tool when the stabilization assembly is mounted adjacent to the lathe and the tool is positioned on the tool rest. The stabilization assembly is provided with an articulation assembly. The articulation assembly supports the boring member and permits horizontal movement of the boring member about the vertical axis, while also permitting lateral movement of the boring member in a horizontal direction.

A cutting tool piece is provided including a rear portion and a lead portion, the lead portion including a front section having an upper side angled downwardly and forwardly and a lower side angled upwardly and forwardly to form a transverse lead cutting edge. The rear portion includes a hole to secure the tool piece to a cutting tool and transverse cutting edges extending outwardly from side walls of the front section. A system is also described for cutting a bowl by coring out an interior portion of a wood block by applying the cutting tool which is curved and rotatably mounted to a post. Its lead end with the tool piece attached creates a circular groove. The cutting tool is advanced on a path which curves toward the central axis of the lathe.

An electron emission element (1) includes an electrode substrate (2) and a thin film electrode (3), and emits electrons from the thin film electrode (3) by voltage application across the electrode substrate (2) and the thin film electrode (3). An electron accelerating layer (4) containing at least insulating fine particles (5) is provided between the electrode substrate (2) and the thin film electrode (3). The electrode substrate (2) has a convexoconcave surface. The thin film electrode (3) has openings (6) above convex parts of the electrode substrate (2).

In a charging process of a shaft furnace, in particular of a blast furnace, batches of charge material are typically discharged in cyclical sequence into the furnace from a top hopper using a flow control valve. A method and system is proposed for adjusting the flow rate of charge material in such a process. Pre-determined valve characteristics for certain types of material are provided, each indicating the relation between flow rate and valve setting for one type of material. According to the invention, a specific valve characteristic is stored for each batch of charge material, each specific valve characteristic being bijectively associated to one batch and indicating the relation between flow rate and valve setting of the flow control valve specifically for the associated batch. In relation to discharging a given batch of the sequence the invention proposes: using the stored specific valve characteristic associated to the given batch for determining a requested valve setting corresponding to a flow rate setpoint and using the requested valve setting to operate the flow control valve; determining an actual average flow rate for the discharge of the given batch; correcting the stored specific valve characteristic associated to the given batch in case of a stipulated deviation between the flow rate setpoint and the actual average flow rate.

A double-chamber vessel for flowable substances having a lateral outer wall with a first chamber enclosed by a first, in particular transparent wall and a second chamber enclosed by a second transparent wall in which the first and second chambers each have an opening which openings end commonly in an opening section of the double-chamber vessel, otherwise they are completely separated from each other, wherein the first chamber is an inner chamber that is enclosed by the second chamber, which is an outer chamber, wherein in planar sections the first wall enclosing the first chamber lies directly against the second wall enclosing the second chamber, at the same time forming the lateral outer wall of the double-chamber vessel, or in the planar sections, the second wall forms the first wall and wherein both chambers have a continuous flow connection to the respective openings.

A fluid flow connector and a method of manufacturing the same wherein the fluid flow connector utilizes a valve having a plunger which is made by overmolding a soft exterior to a hard core. The soft exterior being overmolded to the hard core by either insert or multi-shot methods. The method also including attaching the soft exterior to the hard core mechanically and/or by molecular bonding.

Embodiments herein relate generally to distribution of flow into vessels containing packed beds of media. An example application of such beds is to pressure swing or temperature swing adsorption systems. Systems herein may include a vessel and a distributor for distributing flow into a lower portion of the vessel. The system may include: a vessel comprising a top head and a bottom head; and a bottom head feed/effluent nozzle. A lower distributor having at least one flow permitting surface is disposed within the vessel and encompasses an inlet of the bottom head feed/effluent nozzle. A flow gap is formed between a bottom portion of the lower distributor and the bottom head feed/effluent nozzle.

A snorkel nozzle (10) having a double shell core (16, 26) that defines an annular gap (40) between the shells and that has an array of baffles (66) arranged in the annular gap to define a serpentine flow path for cooling gases that pass through the annular gap.

Disengageable chair-lift station having a transfer way made up of a first longitudinal part extending in alignment with the line of the carrying-hauling cable, and of a second transversal part extending perpendicular to the first part. The driving or return pulley is placed between the sections of the first part, and the disembarkation and embarkation platforms are shifted from one another in the second part, so that the disembarkation and embarkation of the skiers are performed on the same side of the station, in a direction perpendicular to the longitudinal axis of the line.

Aspects of the invention provide a transport system powered by short block Linear Synchronous Motors (LSMs). The use of short blocks allows vehicles to move under precise control even when they are in close proximity to each other. The design allows the vehicles to be propelled and guided while negotiating sharp turns and negotiating merge and diverge switches. A coreless LSM can be used to create propulsive force without attractive force so as to allow a relatively high drag vehicle suspension, such as a vehicle sliding on a smooth surface. Further aspects of the invention provide a switching member that is selectively moveable relative to a guideway in order to change a magnetic force acting on the vehicle transverse to a direction of motion of the vehicle.

The present invention is realized by apparatus and methods for placing a large utility scale photovoltaic array in the low stratosphere of earth's atmosphere at an altitude of about 20 km, above clouds, moisture, dust, and wind. This is accomplished using a large light-weight, rigid, buoyant structure to support the large photovoltaic array. Long, strong and light tethers connect the buoyant structure to the ground and hold it in position against wind forces. The electricity output from the photovoltaic array is then coupled to high voltage transmission lines which connect from the platform to the earth's surface. The electricity is then transmitted through the high voltage transmission lines to the earth's surface where it is connected to the electrical supply grid and provides lower cost, more reliable electricity.

A tower ride is disclosed with suspended cars mounted on rails that that forms track that is a complete double helix path for the car without having to turn the car or switch tracks. The car is suspended from a four truss track, riding on the two bottom rails for stability. Another embodiment is a roller coaster track mounted on a tower.

The invention provides in some aspects a transport system comprising a guideway with a plurality of propulsion coils disposed along a region in which one or more vehicles are to be propelled. One or more vehicles are disposed on the guideway, each including a magnetic flux source. The guideway has one or more running surfaces that support the vehicles and along which they roll or slide. Each vehicle can have a septum portion of narrowed cross-section that is coupled to one or more body portions of the vehicle. The guideway includes a diverge region that has a flipper and an extension of the running surface at a vertex of the diverge. The flipper initiates switching of vehicle direction at a diverge by exerting a laterally directed force thereon.

The present disclosure relates to a component for a railway snow melter. The component includes a mounting plate adapted for connection to a tie duct. The mounting plate defines a point nozzle opening and/or a track duct nozzle. A point nozzle is mounted to the mounting plate at a location above the point nozzle opening. A track duct nozzle is mounted to the mounting plate at a location above the track duct nozzle opening.

A gas turbine engine including a combustor with a combustion liner having inner and outer walls is disclosed herein. The gas turbine engine further includes a swirler system adapted to receive a fuel injector and a flow splitter operable to bifurcate an airflow exiting the swirler system into a first bifurcated flow and a second bifurcated flow. A shroud is positioned downstream of the flow splitter and is configured to deflect the first bifurcated flow in a first direction radially inward and the second bifurcated flow in a second direction radially outward. The second bifurcated flow cools both of the inner and outer walls of the combustor liner.

A method of manufacturing a nozzle assembly may include the step of over molding a nozzle housing, or a portion of a nozzle housing, onto at least one nozzle component, such as an injection tube. Nozzle assemblies and flow cytometers incorporating nozzle assemblies may include any combination of straight smooth injection tubes, improved features for securing a nozzle assembly, improved features for debubbling a nozzle assembly, and aggressive orienting geometries. A method of sorting cells may include the step of magnetically coupling a nozzle assembly with a flow cytometer.

A hand shower has outer housing including a first housing part and a second housing part, is disposed in the interior of the outer housing. The first housing part is produced by dual-component injection molding and has a support formed from a hard component. Alongside the switching device, this support is provided with a passage. A soft component, injected onto the outer side of the support covers the passage in a membrane-like manner. The membrane region of the soft component is elastically deformable to allow the switching device to be operated from the surroundings.

A single point touch shower has a fixed unit, an outlet terminal and a switching mechanism. The fixed unit has an inlet passage connecting the water resource; the outlet terminal is asway connected to the fixed unit and provided with a plurality of outlet functions; the switching mechanism comprises a first ratchet wheel, a stopping claw and a transmission mechanism; the first ratchet wheel is rotationally connected to the outlet terminal; the stopping claw connects the first ratchet wheel and the fixed unit to limit the reversal of the first ratchet wheel; the transmission mechanism connects the first ratchet wheel and the fixed unit to transmit the mutual swing between the outlet terminal and the fixed unit to the relative rotation between the first ratchet wheel and the outlet terminal, and the outlet functions switching is controlled through the relative rotation between the first ratchet wheel and the outlet terminal.

A material spreader assembly for the broadcast spreading of particulate material from the trailer hitch of a vehicle. A hopper for storing the particulate material is supported by a frame having a trailer hitch coupler for connection to the vehicle. A spreader including a spinner driven by an electric motor receives and disperses the particulate material. A control circuit receives electric current from the vehicle via a plug interface and a wiring harness and controls the operation of the spreader. A remote communicates user commands to the control circuit. The control circuit includes a motor control processor that controls a motor power relay and a motor driver to gradually ramp up the current supplied to the spreader for start up the spreader while preventing a high transient current draw spike. Component feedback sensors enable the motor control processor to provide an emergency shut off feature and warning signals.

A turbofan engine (10) employs a flow control device (41) that changes an effective exit nozzle area (40) associated with a bypass flow path (B) of the turbofan engine. A spool (14) couples a fan (20) to a generator (52). The turbofan emergency power system includes a controller (50) that communicates with the flow control device (41). Upon sensing an emergency condition, the controller manipulates the flow control device to reduce the effective nozzle exit area (40) of the bypass flow path, which chokes the flow through the bypass flow path thereby increasing the rotational speed of the fan. In this manner, the generator is driven at a higher rotational speed than if the flow through the bypass flow path was not choked, which enables a smaller generator to be utilized.

Provided is a window glass sheet fitted with a seal member and incorporated with a device such as a deicer which facilitates the device and the seal member to be installed in a proper manner. The automotive window glass sheet comprises a laminated glass sheet including a first glass sheet and a second glass sheet placed on an outboard side of the first glass sheet, and a seal member fitted on a peripheral part of the laminated glass sheet. The automotive window glass sheet further comprises a cutout formed on an edge of the first glass sheet, an electrode provided on a part of the inboard side of the second glass sheet corresponding to the cutout, a lead wire connected to the electrode and a spacer extending along an edge of the second glass sheet on the inboard side of the second glass sheet in a part thereof corresponding to the cutout and defining a flat and smooth inboard surface, wherein the inboard surface of the spacer is flush with a plane extrapolated from an inboard side of the first glass sheet, and the seal member is attached to a peripheral part of the inboard side of the first glass sheet and is attached to the inboard surface of the spacer in the cutout.

A seal assembly for sealing a pressure plate against an opening in a blowout preventer body has a seal groove formed in the pressure plate and a seal in the seal groove. The seal groove has a first groove portion adjacent to a sealing face of the blowout preventer, and a second groove portion extending past the sealing face into the opening of the blowout preventer body. The seal has a first seal portion in the first groove portion and a second seal portion in the second groove portion.

The present invention refers to a seal ring for a mechanical seal, comprising: a base body (2) with a diamond layer (3) which is applied to the base body (2) and configured as a sliding surface, wherein the diamond layer (3) has a thickness (D) which is less than or equal to 4 μm, particularly less than or equal to 3 μm, particularly less than or equal to 2 μm, particularly preferably about 1 μm, and wherein the base body (2) is without fissures or only comprises fissures that have a maximum longitudinal extension (L) on a surface of the base body (2) or in the base body (2) that is less than or equal to 5 μm.

A packer unit for an annular blowout preventer including an annular elastomer body including an elastomer having a unidirectional grain and a quantity of fiber longitudinally aligned with the grain of the elastomer. A method of forming a packing unit for a blowout preventer including forming a fiber reinforced elastomer by aligning fibers with a grain of an elastomer; cutting a portion from the fiber reinforced elastomer in the direction of the grain; loading the cut portion in a packing unit mold such that the grain of the fiber reinforced elastomer of the cut portion is parallel to a packing unit axis; and heating the loaded packing unit mold.

A bellows arrangement on a guide bar of a disc brake, particularly of a commercial vehicle, has an end of the bellows comprising a sealing ring, particularly a quad ring, lying in a circumferential groove of the guide bar. The bellows is pressed into the groove by a retaining ring placed thereon, and is designed so that an air passage can form in the contact area of the sealing ring at the base of the groove, reducing the volume enclosed by the bellows and the guide bar. To this end, the contact shoulder formed on the retaining ring is circumferentially interrupted in segments.

Disclosed is a system and method for decreasing airflow and improving ventilation within a tunnel, such as a railroad tunnel, including a path for movement of a vehicle (e.g., train) therethrough. The system has a plurality of air baffles mounted within the tunnel, each device comprising a body and a mounting device. Each mounting device positions each body inside and along the length of the tunnel between the entrance and the exit. The air baffles are configured to restrict airflow at least in part in a longitudinal direction of the tunnel, thereby increasing a relative difference between a vehicle speed and air speed in a tunnel annulus when the vehicle passes through the tunnel. The restriction (e.g., decrease) of airflow in the tunnel reduces the piston effect resulting from the vehicle or train passing through, thus reducing emissions and heat generated by the locomotives in the tunnel.

An adjustable blocking arrangement for electronic hardware or computer racks, for preventing the undesired leakage of air through rack spaces not filled with hardware. An airflow control device is provided comprising a flexible web and a magazine adapted to receive the part of the flexible web that is not deployed. The device is adapted such that a length of the web may be deployed to sealingly block a space in the rack that is not filled with hardware modules, to prevent the flow of air through the space. The device may comprising a detection system adapted to detect the space in the rack that is not filled with hardware modules, and a processing system adapted to receive a signal from the detection system, and as a function of the signal to automatically deploy or retract the flexible web so as to sealingly block the space.