The Experts below are selected from a list of 24 Experts worldwide ranked by ideXlab platform

Dominik Uram - One of the best experts on this subject based on the ideXlab platform.

  • Minor surgery for the repair of retinal detachment emanating from retinoschisis.
    Acta ophthalmologica, 2008
    Co-Authors: Harvey Lincoff, Ingrid Kreissig, Dominik Uram
    Abstract:

    . Purpose:  To propose a mechanism for the development of the outer layer retinal tears that occur with retinoschisis and the detachment emanating from it that is consistent with the limited extent of the detachment and the response to binocular occlusion and Local Buckles. Methods:  A consecutive series of 24 patients with retinoschisis, collected over 15 years, was analysed. Seven patients developed a symptomatic retinal detachment emanating from breaks in the outer layers of retinoschisis. The detachments responded to binocular occlusion, a sponge Buckle, or a temporary balloon Buckle and laser coagulation to the edges of the breaks. Results:  Two retinas attached completely after 48 hr of binocular occlusion, four responded to Local sponge Buckles and one to a temporary balloon Buckle. All attached without drainage of subretinal fluid. Final visual acuity was 20/20 in six eyes and 20/25 in one eye. Conclusion:  The detachment emanating from retinoschisis responds to ocular rest or a Local Buckle to breaks in the outer layers. It is proposed that the mechanism for the detachment that emanates from retinoschisis is intraretinal traction by residual transretinal fibres at the edge of the schisis cavity.

Nk Karri - One of the best experts on this subject based on the ideXlab platform.

  • HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT BUCKLING EVALUATION METHODS AND RESULTS FOR THE PRIMARY TANKS
    'Office of Scientific and Technical Information (OSTI)', 2009
    Co-Authors: Tc Mackey, Ki Johnson, Je Deibler, Sp Pilli, Mw Rinker, Nk Karri
    Abstract:

    This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive anchor bolt failure and the appropriateness of the safety factors that were used for evaluating Local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the concrete anchor bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive anchor bolt failure leading to global buckling of the tank under increased vacuum) could occur. After releasing Revision 0 of this report, an independent review of the Double Shell Tanks (DST) Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis was conducted by Dr. Robert P. Kennedy of RPK Structural Mechanics Consulting and Dr. Anestis S. Veletsos of Rice University. Revision I was then issued to address their review comments (included in Appendix D). Additional concerns involving the evaluation of concrete anchor loads and allowables were found during a second review by Drs. Kennedy and Veletsos (see Appendix G). Extensive additional analysis was performed on the anchors, which is detailed by Deibler et al. (2008a, 2008b). The current report (Revision 2) references this recent work, and additional analysis is presented to show that anchor loads do not concentrate significantly in the presence of a Local Buckle

Deric J. Oehlers - One of the best experts on this subject based on the ideXlab platform.

  • Local BUCKLING OF SIDE-PLATED REINFORCED-CONCRETE BEAMS. II: EXPERIMENTAL STUDY
    Journal of Structural Engineering, 1999
    Co-Authors: Scott T Smith, Mark A. Bradford, Deric J. Oehlers
    Abstract:

    A series of experiments on side-plated reinforced-concrete beams is reported. The experiments are used to investigate the Local buckling of mild steel plates bolted to the sides of reinforced concrete beams, and to verify the theoretical results obtained in Part I. Thirteen loading regimes have been undertaken on two simply supported beams. Within each loading run, a section of plate at a particular point along the beam was isolated, and the beam loaded until a Local Buckle was produced. Each new position gives a unique combination of in-plane axial, bending, and shear plate actions. The results are presented in graphical and tabular form, and conclusions are drawn from a comparison of the experimental and theoretical findings. Both beams were eventually tested to failure, and the effect of Local buckling on the ultimate strength and ductility of the composite beam was assessed

Harvey Lincoff - One of the best experts on this subject based on the ideXlab platform.

  • Minor surgery for the repair of retinal detachment emanating from retinoschisis.
    Acta ophthalmologica, 2008
    Co-Authors: Harvey Lincoff, Ingrid Kreissig, Dominik Uram
    Abstract:

    . Purpose:  To propose a mechanism for the development of the outer layer retinal tears that occur with retinoschisis and the detachment emanating from it that is consistent with the limited extent of the detachment and the response to binocular occlusion and Local Buckles. Methods:  A consecutive series of 24 patients with retinoschisis, collected over 15 years, was analysed. Seven patients developed a symptomatic retinal detachment emanating from breaks in the outer layers of retinoschisis. The detachments responded to binocular occlusion, a sponge Buckle, or a temporary balloon Buckle and laser coagulation to the edges of the breaks. Results:  Two retinas attached completely after 48 hr of binocular occlusion, four responded to Local sponge Buckles and one to a temporary balloon Buckle. All attached without drainage of subretinal fluid. Final visual acuity was 20/20 in six eyes and 20/25 in one eye. Conclusion:  The detachment emanating from retinoschisis responds to ocular rest or a Local Buckle to breaks in the outer layers. It is proposed that the mechanism for the detachment that emanates from retinoschisis is intraretinal traction by residual transretinal fibres at the edge of the schisis cavity.

Tc Mackey - One of the best experts on this subject based on the ideXlab platform.

  • HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT BUCKLING EVALUATION METHODS AND RESULTS FOR THE PRIMARY TANKS
    'Office of Scientific and Technical Information (OSTI)', 2009
    Co-Authors: Tc Mackey, Ki Johnson, Je Deibler, Sp Pilli, Mw Rinker, Nk Karri
    Abstract:

    This report documents a detailed buckling evaluation of the primary tanks in the Hanford double-shell waste tanks (DSTs), which is part of a comprehensive structural review for the Double-Shell Tank Integrity Project. This work also provides information on tank integrity that specifically responds to concerns raised by the Office of Environment, Safety, and Health (ES&H) Oversight (EH-22) during a review of work performed on the double-shell tank farms and the operation of the aging waste facility (AWF) primary tank ventilation system. The current buckling review focuses on the following tasks: (1) Evaluate the potential for progressive anchor bolt failure and the appropriateness of the safety factors that were used for evaluating Local and global buckling. The analysis will specifically answer the following questions: (a) Can the EH-22 scenario develop if the vacuum is limited to -6.6-inch water gage (w.g.) by a relief valve? (b) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario can develop? (c) What is the appropriate factor of safety required to protect against buckling if the EH-22 scenario cannot develop? (2) Develop influence functions to estimate the axial stresses in the primary tanks for all reasonable combinations of tank loads based on detailed finite element analysis. The analysis must account for the variation in design details and operating conditions between the different DSTs. The analysis must also address the imperfection sensitivity of the primary tank to buckling. (3) Perform a detailed buckling analysis to determine the maximum allowable differential pressure for each of the DST primary tanks at the current specified limits on waste temperature, height, and specific gravity. Based on the concrete anchor bolt loads analysis and the small deformations that are predicted at the unfactored limits on vacuum and axial loads, it is very unlikely that the EH-22 scenario (i.e., progressive anchor bolt failure leading to global buckling of the tank under increased vacuum) could occur. After releasing Revision 0 of this report, an independent review of the Double Shell Tanks (DST) Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis was conducted by Dr. Robert P. Kennedy of RPK Structural Mechanics Consulting and Dr. Anestis S. Veletsos of Rice University. Revision I was then issued to address their review comments (included in Appendix D). Additional concerns involving the evaluation of concrete anchor loads and allowables were found during a second review by Drs. Kennedy and Veletsos (see Appendix G). Extensive additional analysis was performed on the anchors, which is detailed by Deibler et al. (2008a, 2008b). The current report (Revision 2) references this recent work, and additional analysis is presented to show that anchor loads do not concentrate significantly in the presence of a Local Buckle