Abstract: Material properties between a wellbore and a casing having a partition separating respective domains inside and outside the casing are evaluated by disposing at least one ultrasonic transmitter and a plurality of ultrasonic receivers in longitudinally spaced-apart relationship alongside the partition inside the casing. The ultrasonic transmitter is activated to form ultrasonic waveforms comprising propagated quasi leaky-Lamb waves constituting flexural waves having symmetric and antisymmetric zero-order modes within the partition. A time-shift is applied to the received flexural waves so that the respective time-shifted waveforms corresponding to each of the flexural waves arrive at the same time.

Abstract: Material properties between a wellbore and a casing having a partition separating respective domains inside and outside the casing are evaluated by disposing at least one ultrasonic transmitter and a plurality of ultrasonic receivers in longitudinally spaced-apart relationship alongside the partition inside the casing. The ultrasonic transmitter is activated to form ultrasonic waveforms comprising propagated quasi leaky-Lamb waves constituting flexural waves having symmetric and antisymmetric zero-order modes within the partition. A time-shift is applied to the received flexural waves so that the respective time-shifted waveforms corresponding to each of the flexural waves arrive at the same time.

Abstract: Methods are disclosed for evaluating a material on a remote side of a partition separating first and second domains wherein flexural waves within the partition are received by spaced-apart ultrasonic receivers and processed to determine the velocity of the waves propagating into the second domain from a first receiver to a second receiver located more remote from the transmitter than the first receiver and whose separation from the first receiver is known. Comparison of a theoretical phase velocity with the measured phase velocity of the recorded waves allows determination as to whether the flexural wave is propagating through solid. This may be based on a measurable deviation between the two curves occurring at a critical frequency, which may be identified by a perturbation in a group velocity plot. Discrimination may also be based on the gradient of a straight line that best-fits the attention dispersion of the frequency spectrum.

Abstract: Methods are disclosed for evaluating a material on a remote side of a partition separating first and second domains wherein flexural waves within the partition are received by spaced-apart ultrasonic receivers and processed to determine the velocity of the waves propagating into the second domain from a first receiver to a second receiver located more remote from the transmitter than the first receiver and whose separation from the first receiver is known. Comparison of a theoretical phase velocity with the measured phase velocity of the recorded waves allows determination as to whether the flexural wave is propagating through solid. This may be based on a measurable deviation between the two curves occurring at a critical frequency, which may be identified by a perturbation in a group velocity plot. Discrimination may also be based on the gradient of a straight line that best-fits the attention dispersion of the frequency spectrum.

Abstract: Chair mechanism especially for office chairs and larger arm chairs, characterized in one end of a torsion spring (1); being fixedly connected with one end of an inner pipe (3) being turnably supported in a pipe (4), the other end being supported turnably in an outer pipe (2) which again is secured to the other end of the spring (1), the outer pipe (2) and the pipe (4) being fixedly connected with each other through an angle profile (12) securing a fixed connection between the outer pipe (2), the pipe (4), the angle profile (12), the seat (13) of the chair and the two back supports (10, 11) of the chair which are secured at a distance from each other to respectively the outer pipe (2) or the pipe (4), a pressure arm (8) being connected with a centre portion of the inner pipe (3) between the pipe (4) and the outer pipe (2) and the pressure arm (8) abutting with a prestress against a bow mechanism (5) connected to the fundament of the chair and adjustable by means of a screw (9).

Abstract: Device for locking in a chair seat in a desired angular position, comprising several lamellae (1) connected with the seat, extending through a retainer (7) and between fixed lamellae (2) arranged in the retainer, whereby clamping shoes (3, 4) which are abutting against the outer fixed lamellae (2) may be clamped by bolts (5, 6) for locking the position of the seat and providing possibility for adjustment of the clamping points of the bolts, where lameellae (1) without holes are arranged abutting against fixed lamellae (2) across their width, the lamellae (1) being connected with the seat of the chair, the fixed lamellae (2) being captured by the retainer (7) and the bolts (5, 6), each provided with a clamping shoe (3, 4) and aligned axially.

Abstract: A straight type torsion spring is clamped together at two ends, the ends being rotatable in relation to each other against the torsion spring force. The torsion spring includes at least four identical torsion rods abutting laterally along their entire extension, thereby utilizing the relatively large twisting angle of the small dimension torsion rods combined with the total torsion force of the torsion spring rods, each of which is independently twisted helically when activating the spring. An adjustable mounting for a chair uses a torsion rod of this type, a seat frame, a back frame, a mounting bracket, and a tilting lever. One end of the torsion spring is secured to the mounting bracket, an upper end of the tilting lever is pivotally connected to a front portion of the seat frame and a rear portion of the seat frame is pivotally connected to the back frame.

Abstract: Adjustable chair, whereby the seat of the chair comprising on each side a rail (10) secured to a front portion under the seat (3) and resting on a roller (11) connected with the chair frame, the seat being, in the rear portion on each side, connected turnably with a guide (5) secured to the frame where the guide having slideably arranged a first glider (6), the back (4) comprising a downwards and forwards directed prolongation and being turnably connected with the first glider (6), the front end of the prolongation being turnably connected with a second glider (8) being slideably arranged on a second guide (7), the second guide thereby being connected with the frame, and first and second guides (5, 7) being arranged in an obtuse angle in relation to each other such that the distance between the rear portion of seat and the lower portion of the back substantially is maintained whereas the angle between the seat and the back is altered when the back is moved backwards by the user in such a way that the gliders