Abstract: A process for polymerizing C.sub.2 -C.sub.10 -alk-1-enes in the presence of a metallocene complex of the formula I ##STR1## where the substituent groups have the meanings described in the specification.

Abstract: A process for preparing oligomers and polymers, obtained fromA) from 0.001 to 100 mol % of at least one aminoalkene of the formula I ##STR1## where X is an integer from 0 to 25 andR.sup.1 to R.sup.6 are hydrogen, C.sub.1 - to C.sub.10 -alkyl, 5- to 7-membered cycloalkyl which, in turn, can carry C.sub.1 - to C.sub.6 -alkyl groups as substituents or C.sub.6 - to C.sub.15 -arylandB) from 0 to 99.999 mol % of at least one alkene,for x=1 in formula I propene being excluded as component B).

Abstract: In a fast Ethernet, each station is connected to the hub by four unshielded twisted pairs. A first pair is transmit only for the station and receive only for the hub, a second pair is transmit only for the hub and receive only for the station, and the third and fourth pairs are bidirectional. Both the station and the hub use their transmit only and the bidirectional pairs for data transmission and their receive only pair for collision detection.

Abstract: Oligomers and polymers, obtainable fromA) from 0.001 to 100 mol % of at least one aminoalkene of the general formula I ##STR1## where X is an integer from 0 to 25 andR.sup.1 to R.sup.6 are hydrogen, C.sub.1 - to C.sub.10 -alkyl, 5- to 7-membered cycloalkyl which, in turn, can carry C.sub.1 - to C.sub.6 -alkyl groups as substituents or C.sub.6 - to C.sub.15 -aryl andB) from 0 to 99.999 mol % of at least one alkene,for x=1 in formula I propene being excluded as component B).

Abstract: A supported catalyst system that is obtained bya) reacting a finely divided carrier with an a-trisalkoxy-silyl-.omega.-haloalkyl compound,b) adding a metallocene complex of the indicated formula I to the reaction product of a);c) reacting the product of b) with a quaternizing agent; andd) optionally adding an open-chain or cyclic alumoxane compound.The catalyst system can be used to prepare polymers of C.sub.2 -C.sub.10 -alk-1-enes.

Abstract: Metallocene complexes of the general formula I ##STR1## where the substituents Y, M, x, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are as described in the disclosure, and ligand systems of the general formula II ##STR2## as intermediates.

Abstract: In a fast Ethernet, each station is connected to the hub by four unshielded twisted pairs. A first pair is transmit only for the station and receive only for the hub, a second pair is transmit only for the hub and receive only for the station, and the third and fourth pairs are bidirectional. Both the station and the hub use their transmit only and the bidirectional pairs for data transmission and their receive only pair for collision detection.

Abstract: Propylene polymers containA) a semicrystalline propylene homopolymer having a melting point of 125 to 165.degree. C. and a glass transition temperature which is greater than -10.degree. C. andB) a semicrystalline propylene homopolymer having a melting point below 130.degree. C. and a glass transition temperature which is less than or equal to -10.degree. C. or a non-crystallizing propylene homopolymer having a glass transition temperature which is less than or equal to -10.degree. C.

Abstract: Catalyst systems for the polymerization of C.sub.2 -C.sub.10 -alkenes contain, as active components, a metallocene complex of a metal of subgroup IV or V of the Periodic Table, an oligomeric alumina compound and a cyclic boron compound of the general formula IV ##STR1## where R.sup.18 to R.sup.20 are each C.sub.1 -C.sub.10 -alkyl which may be monosubstituted to trisubstituted by halogen, C.sub.6 -C.sub.15 -aryl or C.sub.1 -C.sub.10 -alkoxy,C.sub.4 -C.sub.7 -cycloalkyl which may be monosubstituted to trisubstituted by halogen, C.sub.1 -C.sub.10 -alkyl or C.sub.1 -C.sub.10 -alkoxy,C.sub.1 -C.sub.10 -alkoxy which may be monosubstituted to trisubstituted by halogen, C.sub.1 -C.sub.10 -alkyl or C.sub.6 -C.sub.15 -aryl, or C.sub.6 -C.sub.15 -aryl which may be monosubstituted to pentasubstituted by halogen, C.sub.1 -C.sub.10 -alkyl or C.sub.1 -C.sub.10 -alkoxy.

Abstract: There is provided a dual pump floating layer recovery apparatus for pumping a floating layer of contaminant out of a well. The apparatus comprises an upper pump and a lower pump. The lower pump creates a cone of depression which increases the amount of the floating layer within the well. The upper pump pumps the contaminant from the well or cone of depression. The upper and lower pumps preferably are gas-actuated pumps. The lower pump preferably includes an automatic switching device to activate the lower pump upon sensing a predetermined amount of fluid within the pump. A gas conduit interconnects the actuation chambers on both pumps such that when the lower automatic pump is provided with pressurized gas, the upper pump is simultaneously provided with the identical pressurized gas. Upon deactivation, both pumps relieve the activation pressure through the lower pump.

Abstract: There is provided an apparatus for obtaining liquid samples from a well which incorporates a vented packer. The packer reduces the amount of groundwater which must be pumped by the pump of the apparatus in order to purge the well by isolating the input of the pump to a reduced volume of groundwater. The region below the packer, which is the region in communication with the pump, is vented to the atmosphere in order to permit the pump to operate at its maximum pumping rate regardless of the recovery rate of the well. The venting of the packer eliminates the condition where the pump is trying to pull a vacuum due to a low recovery rate of the well.

Abstract: There is provided a fluid sampling apparatus for withdrawing samples of groundwater or other fluids from a well or other monitoring site. The apparatus preferably includes pump means, packer means, conduit means and a wellhead assembly that are permanently installed at the well or monitoring site and are thereby dedicated thereto in order to avoid or minimize cross-contamination of samples from site to site. The packer is integral with the pump and isolates the groundwater below the packer in order to minimize the amount of groundwater which must be pumped in order to purge the well prior to taking an acceptable sample. The apparatus preferably also includes a removable and portable controller means adapted for easy and convenient transportation and connection to such dedicated fluid sampling components at various wells or monitoring sites.

Abstract: A self-centering chuck includes a plurality of centering and clamping slides disposed for slide movement to or from a common center, drive slides are associated with the centering and clamping slides, the latter having parallel or slightly oblique orientation to the drive slides means so as to slidingly move at least essentially parallel to the slide movement of at least one of the centering and clamping slides, the centering slides and the drive slides have wedge surfaces; a plurality of shift pins extend transversely to the centering and clamping slides and to the drive slides and cooperate with the wedge surfaces to couple the drive slides to the centering and clamping slides to obtain movement to or from the center of all centering slides; the shift pins each movein one direction in relation to the respective centering and clamping slide when the drive slides moves in one direction, and the shift pins move in an opposite direction when the drive slides move in the respective opposite direction, the moveme

Abstract: A centering and clamping device is provided which comprises a plurality of rod elements, a plurality of clamping slides and reversing and non-reversing transmission elements between the rod elements and clamping slides to convert motion of the rod elements into centering and clamping motion of the clamping slides. Each of the rod elements are in engagement with some of the other rod elements whereby movement of one rod element can transmit motion to at least one other rod element. Various arrangements of the rod elements, slides and transmission elements are disclosed to achieve centering and clamping.

Abstract: A power drive and transmission unit for self centering clamps and chucks has a housing with a cylindrical bore and a piston which is rotatably mounted therein and is acted upon by two linear operating, piston cylinder drives to obtain rotation of the rotating piston in one or the opposite direction. Two or three linearly moving central slide elements which are mounted on said housing for obtaining the centering chuck action elements are connected to the rotating piston by means of pins running in oblong slots in order to convert the rotation of the rotating piston into oppositely linear motion of the slide elements, so that they move towards or away from a common center depending on the direction of rotation of the rotating piston.

Abstract: A tension adjuster is mounted on and is part of an external fixation device comprising frame segments rigidly supporting fixation pins that pass through and immobilize fractured bones during rehabilitation. This tension adjuster securely attaches the fixation pins to the frame segments and adjustably applies tension along the fixation pins to more rigidly secure the fixation pins and to improve the immobilization of the fractured bones. The tension adjuster comprises a threaded slotted screw attached to the fixation pins and comprises a mounting nut having an aperture through which is drawn the threaded slotted tension screw while adjusting the tension along the fixation pins. A tapered pin extending into the aperture of the mounting nut and into a chamfered slot of the threaded slotted tension screw, guides the threaded slotted tension screw through the mounting nut during tension adjustments.

Abstract: A fluid sampling apparatus is disclosed for withdrawing samples of groundwater or other fluids from a well or other monitoring site. The apparatus preferably includes pump means, conduit means and a wellhead assembly that are substantially permanently installed at such well or monitoring site and are thereby dedicated thereto in order to avoid or minimize cross-contamination of samples from site to site. The apparatus preferably also includes a removable and portable controller means adapted for easy and convenient transportation and connection to such dedicated fluid sampling components at various wells or monitoring sites. A recovery, collection and control system for cleanup of leachate or other liquid material or contaminated groundwater from a landsite is also disclosed.

Abstract: The roll dispenser has as a box for receiving a roll of continuous sheet material, having a bottom, a pair of sides oriented longitudinal with respect to the roll, a pair of sides axial with respect to the roll. One of the longitudinal sides is adapted for receiving a cutting element, at least one tongue element is mounted on at least one of the sides of the box in space relation with the longitudinal side receiving the cutting element. The tongue prevents the recoil of the free end of sheet material onto the roll. In one embodiment, the roll dispenser further comprises a longitudinal side defining the top of the box, at least a portion of its longitudinal sides hingedly mounted to define a gap near the cutting and tongue elements. Also disclosed is a blank for constructing the box.

Abstract: The carton is formed with a transverse partition formed by a first partition panel foldably connected to a glue panel of the box and having a second partition panel foldably connected thereto along the fold line substantially perpendicular to the fold line connection between the first partition panel and the glue panel. The second partition panel had a glue flap at its opposite end which is connected to its adjacent end wall of the carton. A transverse partition is formed in each of the first and second partition panels with the transverse partition panel formed from the first partition being at the end of the first partition remote from the said glue panel and the transverse partition in the second partition panel being formed adjacent the said glue panel. The transverse partitions are connected to their respective partition panels via fold lines substantially parallel to the fold line connection between the first partition panel and the glue panel.

Abstract: An improved external fixation device is disclosed composed of a pair of arcuate frame segments and multiple adjustment rods and pin holders, which cooperate with one another as well as plural pins extending through the soft tissue and bone of a patient to rigidly immobilize a bone fracture and permit compression, neutralization or distraction of the fracture from a location external to the body.