Identification Of Joints Research Articles

IDENTIFICATION OF FLEXIBLE JOINTS IN VEHICLE STRUCTURES

A probabilistic estimation method for identification of flexible joints in vehicle structures is presented. The method identifies the most important parameters of a joint model and estimates their values by using displacement measurements. Thus, this method can be used to develop simple, design-oriented joint models for preliminary structural design. This method was applied to the identification of joints in a plane frame structure.

Comparative local anaesthetic blocks in the diagnosis of cervical zygapophysial joint pain

The utility of randomised, double-blind, controlled, comparative local anaesthetic blocks for the diagnosis of cervical, zygapophysial joint pain was studied in 47 patients with chronic neck pain following whiplash injury. Each patient was investigated with radiologically controlled blocks of the medial branches of the cervical, dorsal rami to anaesthetise the target cervical, zygapophysial joint. The blocks were performed using either lignocaine or bupivacaine, randomly allocated, and the patients' responses were assessed in a double-blind fashion. Any positive response was subsequently assessed by repeating the block with the complementary anaesthetic. Only those patients experiencing a longer period of pain relief from the bupivacaine were considered to have true-positive responses. Forty-four patients had pain relief from two blocks at a single level, of whom 34 had longer pain relief from bupivacaine. This result is unlikely to have occurred by chance ( P = 0.0002). The durations of pain relief obtained from the anaesthetics were consistent with the known characteristics of these drugs with bupivacaine lasting significantly longer than lignocaine ( P = 0.0003). A subgroup of 13 patients were identified with unexpected, prolonged responses to one or both of the anaesthetics. Comparative, diagnostic blocks are a valid technique in the identification of painful zygapophysial joints, and constitute an implementable alternative to normal saline controls.

A code for the identification of tubular joints from the structural model of a steel jacket for fatique analysis

A FORTRAN code and the algorithm for identification of tubular joints of types T, Y, X, K, KT and SKT from structural data of a jacket is presented. This task arises in fatigue analysis of all joints in the structure where identification of all possible joints is not feasible without a code.

Biased reading frames of pre-existing DH--JH coding joints and preferential nucleotide insertions at VH--DJH signal joints of excision products of immunoglobulin heavy chain gene rearrangements.

During B cell differentiation immunoglobulin (Ig) DH segments join to JH segments, followed by joining of VH to DJH. Although circular excision products of DH--JH rearrangements have been characterized, excision products of VH to DJH joining have never been isolated. We selectively denatured chromosomal DNA of mouse splenocytes and enriched circular DNA spanning the long distance between VH and DH. Subsequent PCR amplifications allowed the identification of signal joints of VH to DJH. Sequence analysis indicated that preexisting DH--JH coding joints of excision products showed a strong bias for reading frame 1, and the absence of reading frame 2, which would allow the expression of a truncated mu chain called D mu protein. When comparing the joints of the VH--DJH and DH--JH rearrangements we observed N-nucleotide insertions to be abundant at the VH--DH signal joint, but very sparse at the DH--JH signal joint, while the coding joints of both contained abundant N-insertions. These differences in N region insertions at the signal joints suggest a differential control of the D--J and V--DJ rearrangements.

Identification of flexible joints in vehicle structures

A method for identification of flexible joints in vehicle structures is presented. The method identifies the most important parameters of a joint model and estimates their values by using displacement measurements of the overall structure. Thus, the method can be used to develop simple, design-oriented joint models that are suitable for preliminary structural design. The viability of the proposed method is demonstrated by applying it to plane frame structures with flexible joints. Nomenclature b = vector of parameter estimates bj = vector of parameter estimates obtained by using the y'th data subset C — covariance matrix Cjb — covariance matrix of parameters obtained by the jth data subset / = force vector K = global stiffness matrix Kj = stiffness matrix of a joint KR = stiffness matrix of the vehicle structure without joints u = vector of displacements um = vector of measured displacements u = vector of estimated displacements jc = vector of regressor variables Z = matrix of sensitivity derivatives of the displacements with respect to the parameters of the joints j8 = vector of parameters of a joint model y = the vector of transformed joint parameters in principal direction analysis e = vector of measurement errors (n) = combinations of n objects taken m at a time Subscripts b = vector of parameter estimates s = vector of measurement errors

Force-state mapping identification of nonlinear joints

A procedure is presented for identifying the potentially strong nonlinear properties of structural members, such as joints, by expressing the force transmitted by the member as a function of its mechanical state. By explicitly including position- and rate-dependent effects, the surface of the transmitted force vs state—the forcestate map—has distinct, unique, superposable features for common structural nonlinearities, even those that appear to indicate hysteresis on a force-stroke presentation. An analysis is performed on the influence of true memory effects, transient response, and uncertainty in the measurements and system mass on the precision of the procedure. The successful identification of simulated data verifies the accuracy of the identification algorithm. Tests are then conducted on three actual joint models, with incomplete state measurements typical of an actual testing environment. The ability of the procedure to estimate the complete state vector and to analyze and reconstruct the measured nonlinear characteristics is demonstrated.