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Sandwich plates consist of a total of three layers, with a thick core layer between two thin face layers. The face layers provide resistance to bending, while the core layer provides resistance to shear. General purpose finite element softwares are one of the most suitable and widely used analysis methods to investigate the behavior of structures. Many design parameters can be easily examined by using these analysis programs. In this study, the buckling behavior of sandwich square plates simply supported on four sides, whose ratio of core layer thickness to face layer thickness is between 7 and 9, was investigated using a general purpose finite element software. The effect of thickness variation was investigated by varying the face and core layer thicknesses of sandwich plates with a constant total thickness. At the same time, the materials of the face and core layers were changed and the most suitable design for the buckling behavior was revealed. For this purpose, 110 analyzes were made with 2 different face materials, 5 different core materials, 11 different thickness ratios. According to the results obtained from the analysis, the maximum critical buckling load was calculated as 282.108 N/mm2 in the sandwich plate with steel face and PVC H200 core. The most suitable design of sandwich plates against buckling was determined by presenting the results with graphics. [ABSTRACT FROM AUTHOR]

In this article, the optimum stacking sequence with maximum buckling load factor of a plate made of M91/IM10 unidirectional prepreg material, which has a very high strength compared to the materials used in the aerospace industry, is obtained by genetic algorithm method. The composite plate in question is simply supported at 4 edges and subjected to biaxial in-plane compressive loads. With the computer code developed using the genetic algorithm method, stacking sequences that provide maximum buckling strength at certain fiber angle ranges and certain number of layers for various load cases and various plate aspect ratio combinations are obtained. The laminate is assumed to be symmetrical and balanced. The results are compared with the results obtained from graphite/epoxy composite material, which has been studied in the literature. The comparison reveals that a plate made of M91/IM10 prepreg material can provide the same buckling performance with lighter structures than graphite epoxy. [ABSTRACT FROM AUTHOR]

The current investigation aims at enhancing the buckling characteristics of basalt fiber-reinforced composites by incorporating nano clay (NC) particles into the epoxy matrix system. Basalt fiber-reinforced composite laminates containing different NC concentrations (0.0%, 0.5%, 1.0%, 1.5%, 2.0% and 3.0%) by weight have been manufactured by vacuum-assisted resin transfer molding method and subjected to axial and lateral compression loadings to determine the effects of NC particles on buckling properties. Also, the influences of NC particles on material structure were examined by analysis with SEM micrographs of buckled samples. The results demonstrate that introduction of NC particles has significant effects on both axial and lateral buckling behaviors. Compared to pure samples, the highest improvements obtained for axial and lateral critical buckling loads were 48.1% and 39.56%, respectively, from the sample having 1% NC. Further increasing amount of NC particle content have exhibited reductions in critical buckling loads. This can be explained by poor interfacial bonding as a result of agglomerations and exfoliation of nanoparticles at epoxy/basalt interfaces in certain areas. According to obtained results, the application of NC inclusion has proved to be compatible with structure of basalt fiber-reinforced composites and they might be used together for applications requiring high buckling resistance. [ABSTRACT FROM AUTHOR]

In this article, the buckling of carbon nanotube (CNT) patterned cylindrical shells subjected to axial compressive load is presented within the framework of shear deformation theory (SDT). The material properties of nanocomposites change as a linear function depending on the thickness coordinate. The basic equations of cylindrical shells with CNT pattern are derived based on Donnell type shell theory and the critical axial load expression is obtained within the framework of SDT by applying Galerkin method. The effects of transverse shear deformations on the critical axial load of functionally graded CNT patterned cylindrical shells are investigated by changing CNT patterns, volume fraction ratio and shell parameters. [ABSTRACT FROM AUTHOR]

In this study, the buckling of variable cross-section columns under axial load is investigated by the Complementary Functions Method (CFM). Columns whose cross-sectional properties change continuously throughout the element are modeled according to the Timoshenko beam theory. By using the internal force-strain relations and equilibrium equations, a set of first-order ordinary differential equations governing the buckling behavior is obtained. The effects of different taper values and length/thickness ratios on the buckling load along the element are investigated for different boundary conditions. The calculated dimensionless buckling loads are tested with the available values in the literature and the results obtained from the Abaqus finite element program. The applicability of the CFM to the elastic buckling problem of variable cross-section columns has been demonstrated. [ABSTRACT FROM AUTHOR]

In this study, snap-buckling and post-buckling behaviors of fixed beams having initially small circular imperfection subjected to uniformly distributed vertical loads are examined. The effect of a parameter related to the geometry of the initially imperfect beam on the buckling values as well as the deformed shapes of the initially imperfect beam, support reactions and internal forces are investigated. The finite difference method and the displacement-controlled Newton-Raphson method are used for the numerical solution of the nonlinear governing differential equations obtained within the framework of the Euler-Bernoulli beam theory. It is observed that the concerning geometric parameter significantly effects the buckling values, deformed shapes of the initially imperfect beam, support reactions and internal forces. [ABSTRACT FROM AUTHOR]

In this study, free vibration and buckling analyses of functionally graded (FGM) sandwich beams is investigated by Navier's method. Displacement field is defined according to the first order shear deformation theory, and the equations of motion are derived by the Lagrange's principle. Volumetric ceramic ratio is defined by a power-law rule. In the analytical solution, different trigonometric series functions are used for each end conditions considered. Two cases of functionally graded sandwich beams are considered: a) Homogeneous ceramic core and FGM faces (Type A), and b) FGM core and homogeneous faces (Type B). Natural frequencies and buckling loads are obtained for different boundary conditions, power-law indices and slenderness. Numerical results are compared with the available literature, and a good agreement are obtained between the results. [ABSTRACT FROM AUTHOR]

Second order effects caused by internal forces in slender systems generate additional internal forces and deflections. Stability problems occur, when the additional internal forces and deflections do not converge (flexural buckling). Furthermore, lateral buckling is also possible due to very small rotations perpendicular to the beam cross-section (lateral torsional buckling). This stability problem has been studied by number of researchers and is one of the main topics in engineering. Except certain types of structures, it is difficult to formulate a closed-form solution. It will be helpful to develop numerical solutions for these systems. In this study, stiffness matrix calculation with respect to both flexural and torsional buckling is presented. Buckling problems in curved or tapered crosssection systems can be analyzed by dividing the beams into finite segments. Within this framework, an application is presented regarding the flexural and lateral torsional buckling in 2nd degree parabolic arches. [ABSTRACT FROM AUTHOR]

In this study, the thermal buckling analysis of the non-homogenous shallow spherical shell is investigated. Firstly, the analytical modeling of non-homogenous material properties and appropriate thermal expansion coefficient which vary continuously through the thickness direction is made. In the formulation of the problem, Kirchhoff-Love's first order shell theory is used and Hooke's law is taken into account for stress-strain relations. By using Donnell-Mushtari-Vlasov's (DMV) assumptions and linear stress-displacement relation, the stability equations depending on three displacements are obtained. Stability equations are solved for the simply supported boundary condition and analytical expression for the dimensionless critical uniform temperature rise is found. In numerical computations, the effects of variations of the elasticity modulus and appropriate thermal expansion coefficient as a power function according to thickness direction and variation of the geometric parameters of the sphere on the critical uniform temperature rises are examined as. To test the validity of this study, the obtained results are compared with counterparts in the open literature. [ABSTRACT FROM AUTHOR]

In this study, the critical buckling loads of natural fiber reinforced glass fiber composite specimens with different stacking sequences kept in seawater were experimentally investigated. Jute and glass fabrics as fiber and epoxy resin as matrix were used to produce the composites in different configurations. Alkali treatment was applied to jute fabrics in order to increase the amount of adhesion between the reinforcement and the matrix. Composite specimens were subjected to buckling test kept in seawater and room conditions for two months (60 days). Critical buckling loads of natural fiber reinforced composite specimens were determined in the direction of the data obtained as a result of the tests. As a result of the experimental study, it was seen that sea water influenced the buckling strength of natural composites in the negative direction. When the symmetric and antisymmetric composites were compared, it was observed that the critical buckling stress in the specimens with antisymmetric (02g/902j)us kept in Mediterraneanseawater was lower than those with symmetric sequence(02g/902j)s. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate IS/OS and ELM junction and restauration with spectral-domain optical coherence tomography (SD-OCT), anatomical and functional outcome after scleral buckling surgery (SBS) in macula-off rhegmatogenous retinal detachment (RRD). Materials and Methods: Medical charts of 81 eyes, who underwent SBS for macula-off RRD were retrospectively analysed. Reattachment success rates, pre- and postoperative visual acuity (VA) were examined. Postoperative SD-OCT images were obtained at 6. month to evaluate the status of photoreceptor IS/OS and ELM junction. OCT characteristics were correlated with final VA. Risk factors influencing postoperative VA were evaluated by using linear multivariate logistic regression. P values <0.05 were considered statistically significant. Postoperative at 12. month VA was examined, IS/OS and ELM restauration was evaluated with SD-OCT in 76 eyes. Results: The primary anatomic success rate was 93.8% (76 eyes), final success rate was 98.8% (80 eyes). Preserved ELM (p=0.003) and IS/ OS integrity (p=0.029), drainage of subretinal fluid (p<0.0001) were significant independent factors for influencing postoperative VA favourable. Duration of detachment >6 days (p=0.04), two/three retinal breaks (p<0.0001) and severe IS/OS disruption (p<0.0001) were significant independent risk factors for a poor postoperative VA. Severe IS/OS disruption was the most important risk factor for poor postoperative VA. Posoperatively at 12 months in 64% and 52% of eyes IS/OS and ELM restauration with increase in VA was detected Conclusion: IS/OS and ELM-integrity may be important independent predictors of postoperative VA. Severe IS/OS disruption may be the most important risk factor for poor postoperative VA. IS/OS and ELM restauration may permit increase in VA. [ABSTRACT FROM AUTHOR]

Commercial utilization of the nuclear energy becomes possible through the controlled fission reaction that occurs within the nuclear reactors. Controlled realization of the fission reaction depends on the neutron number staying constant. This is called criticality condition. In the simplest approximation, the neutrons that trigger the fission reaction can be separated into two groups as low energy thermal neutrons and high energy fast neutrons. This is named two group neutron diffusion theory. In this work, the reactor radius that satisfies the criticality for a given reactor composition has been determined by solving the two group criticality equation numerically. In this manner, the effects of changes in principal and alternate buckling on critical reactor radius have been elucidated in a detailed way. [ABSTRACT FROM AUTHOR]

Nanotechnology is a field of applied science and technology covering a broad range of topics. The main unifying theme is the control of matter on a scale smaller than 1 micrometer, normally between 1-100 nanometers, as well as the fabrication of devices on this same length scale. Nanotechnology cuts across many disciplines, including colloidal science, chemistry, applied physics, materials science, and even mechanical and electrical engineering. Carbon NanoTube (CNT) is a new form of carbon, configurationally equivalent to two dimensional graphene sheet rolled into a tube. It is grown now by several techniques in the laboratory and is just a few nanometers in diameter and several microns long. They are the stiffest and strongest known fibers and have unique electrical properties. An ideal nanotube can be thought of as a hexagonal network of carbon atoms that has been rolled up to make a seamless cylinder. In classical elasticity theory the stress tensor at a given point depends linearly on the strain tensor of the same point. Thus, local elastic theory contains no information about the long range forces etween atoms i.e., there is no internal length scale. On the other hand, the theory of nonlocal continuum mechanics assumes that the stress state at a given reference point is considered to be function of the strain states of all points in the body. Properties of materials at the nanoscale differ fundamentally from those of their bulk counterparts. Carbon nanotubes are one of the structural elements that are used in nanotechnological applications widely. In this study, they are envisioned as hollow cylindrical bars of graphitic carbon at the nanoscale. For these reasons nonlocal theory is more capable to display the mechanical behaviour of materials at the nanoscale. Carbon nanotubes hold substantial promise for the development of nanotechnology. However, thorough understanding of the mechanical behavior of carbon nanotubes is essential. Currently, theoretical treatment of buckling of carbon nanotubes has relied on the use of classical continuum mechanics models, such as the elastic shell model or the Bernoulli-Euler beam bending model. Although classical continuum models are relevant to some extent, and efficient in computation for models at large length scales, the applicability of these classical continuum models at small length scales is questionable. Multiple recent experimental results have shown a significant size-effect in mechanical properties when the dimensions of the specimen or the probed material volume become small. The classical continuum theories lack the capability of representing such effects since they do not include any internal length scale. Consequently, these theories are expected to fail when the specimen size become comparable with the internal length scale(s) of the material. Several modifications of the classical elasticity formulation have been proposed to address this deficiency. They are of nonlocal or gradient type and, as a common feature, include one or several intrinsic length scales. Nonlocal elasticity theory was proposed to account for the scale effect in elasticity by assuming the stress at a reference point to be a function of strain field at every point in the body. When the structure considered falls into the nanometer range, nonlacality parameter ? has a significant influence on the outcomes of this study. In some cases, the ratio of local and nonlocal buckling loads can be 1.4. The buckling of carbon nanotubes has been studied by molecular mechanics in literature. In this paper the method of initial values is used in the frame of nonlocal elasticity. This method gives the values of the displacements and stress resultants throughout the rod once the initial displacements and initial stress resultants are known.… [ABSTRACT FROM AUTHOR]

In this study, the effects of cold environment and different fiber combinations on lateral buckling behavior of hybrid composite beams were investigated, experimentally. For the lateral buckling tests, 12-layered hybrid composite plates were produced using different combinations of carbon, E-glass and aramid fibers, with an epoxy resin system as the matrix (Araldite LY1564/Aradur 3486). The hybrid composite samples were subjected to lateral buckling test after waiting for 90 days in room conditions, 90 days and 150 days in a cooler, respectively. The lateral buckling behaviors of layered hybrid composite beams were investigated in the direction of the data obtained from the lateral buckling tests. The highest critical lateral buckling load was obtained in the CAG30 specimens with the stacking sequence [(30/-60)3]s. The lowest critical lateral buckling load was obtained in GAC samples with the stacking sequence [(0/90)3]s. It has been observed that critical lateral buckling loads of specimens kept in cold environment increased with critical buckling loads of samples in room conditions. As a result of the study, it was determined that the critical lateral buckling loads of the hybrid specimens kept in the cold environment increased with respect to the critical lateral buckling loads of the hybrid specimens kept in room conditions. [ABSTRACT FROM AUTHOR]

In this study, the post-buckling behavior of shells is investigated using 9-noded isoparametric shell elements. Total Lagrangian approach is used in the formulation and shell material is assumed to be linearly elastic. Non-linear equilibrium equations are solved by arc-length method. Various examples were analyzed to obtain postbuckling behavior of shells. [ABSTRACT FROM AUTHOR]

In the study, two and three-dimensional bending, buckling, and free vibration analysis of homogenous and isotropic rectangular plates are made by the method of differential quadrature. The weighting coefficients for differential quadrature are obtained using the power, Chebyshev and Lagrange polynomials. The governing differential equations (constitutive equations and boundary conditions) are reduced to a linear algebraic equations or a standard eigenvalue equation in terms of the unknown function values at the grid points in the field domain via differential quadrature method. The obtained results are then compared with the other results in the related literature. It is found that the obtained results are suitable in point of view the engineering analysis concept. [ABSTRACT FROM AUTHOR]

In steel structures, beams are usually assembled so as to be under bending about their major axis in order to use the structural material economically. Two major problems take place in design of these steel beams. First problem is exceeding of yield stress at the extreme fiber of the section. External force magnitude for any loading case which causes exceeding of yield stress on a steel beam can be easily calculated. Second problem is loss of stability. In beams which are loaded so as to be under bending about their major axis an equilibrium state is also possible for a certain load magnitude, in which the beam is twisted and buckled about its weak axis. This case is called lateral torsional buckling. Depending on the loading case, yield stress of the structural material and slenderness of the beam, which is related to section properties and length of the element, lateral torsional buckling may occur before the extreme fiber of the section reaches to yield stress. In this case, instead of first yield moment, lateral torsional buckling moment should be considered in design of the beam. In this paper, application of finite differences method for determining elastic critical lateral torsional buckling moment of cantilever I sections which are loaded from shear center is presented. The results are compared with ABAQUS software and it is seen that results obtained from the presented 1D model and ABAQUS software coincide. [ABSTRACT FROM AUTHOR]

Buckling restrained braces (BRBs) have high energy dissipation capacity and equal tension and compression axial load capacity. Therefore, the application of BRBs has gained popularity in seismic regions. The first studies on BRBs started in Japan in 1970 and since then more studies have been undertaken in other earthquake prone countries. Although the BRBs perform well in component and subassembly tests, they do not perform as well in frame tests because of the interaction between beam-column-gusset plate and BRB. In this study, the component and subassembly test of the BRBs and then BRB frame tests available in the literature are summarized. [ABSTRACT FROM AUTHOR]

Potential use of aluminum alloy core material as an alternative to steel in BRBs was investigated. Effectiveness/superiority of such braces that are designed, produced, and tested for the first time in this work, over the available types of BRBs is evaluated. Numerous tensile test specimens (coupons) were prepared in prototype samples according to the prescribed standards. Material test results contain valuable information for choosing the materials to be used in designing and fabricating the BRBs. A strain-gauge placement configuration was also suggested and tested in order to correctly measure the axial strains in the yielding portions of BRB cores. The reasons of why A5083-H111 aluminum alloy materials were preferred in the fabrication of BRB-AC1 and BRB-AC3 specimens were given in detail. Fabrication steps of aluminum alloy BRBs, welding procedures followed, assumed cyclic loading test protocol, instrumentation and data acquisition system used in the tests were described in the scope of this study. Experimentally obtained force-displacement hysteretic curves, tension and compression capacities, dissipated cumulative energies (Eh), cumulative inelastic displacements (η), and effective damping ratios (ξeffb) were calculated and compared. The requirement indicating that tests must involve the highest compression adjustment factor (β < 1.3), ensuring the symmetrical hysteretic curves, was fulfilled. It is concluded that aluminum alloy BRBs (BRB-AC3) with weld-free end connections have superior behavioral values when compared to aluminum alloy BRBs with welded end connections (BRB-AC1). [ABSTRACT FROM AUTHOR]

Purpose: To evaluate anatomic, functional success, results of scleral buckling surgery performed to rhegmatogenous retinal detachment cases and factors affecting the surgery results. Materials and Methods: Skleral buckling surgery was performed to 78 rhegmatogenous retinal detachment cases in our clinic between June 2005 and August 2011 and medical records of these cases were evaluated retrospectively. General characteristics of the patients, etiologic factors, anatomical and functional successes and possible factors those may have a role on these results were evaluated. Results: 45 of the eyes (57.7%) were phakic, 29 were pseudophakic (37.2%) and 4 of them were aphakic (5.1%). It was determined that phakic patients had both anatomically and functionlly more successful results. The short duration of the application time was found to be significant for functional success, but not to be effect for anatomical success (respectively p=0.003, p=0.127).. Before the surgery in 67 of the cases (85.9%), macula was inside the detachment area, in 11case (14.1%) macula was reattached. Macular involvement was compared for anatomic and functional success and no significant difference was established. After an average of 23.7 months follow-up; functional success in 47 (60.3%) cases and anatomic success in 66 (84.6%) cases were obtained. Conclusions: Best results may be obtained when the appropriate surgical method was performed on time with the use of appropriate material for the scleral buckling surgery of rhegmatogenous retinal detachment. [ABSTRACT FROM AUTHOR]

Objectives: To compare the results of scleral buckling surgery with and without use of operating microscope for primary rhegmatogenous retinal detachment (RRD). Materials and Methods: This comparative study consisted of 74 eyes of 74 patients who underwent scleral buckling for primary RRD. Group 1 consisted of 35 patients (17 male and 18 female) who were operated using operating microscope and Group 2 consisted of 39 patients (19 male and 20 female) who were operated without operating microscope. Patients with post-equatorial breaks, retinal breaks greater than 90°, proliferative vitreoretinopathy (≥C2), and those with follow-up period of less than sıx months were excluded from the study. The two groups were compared based on age, sex, etiology, anatomic success, and surgical complications (scleral perforation, iatrogenic retinal breaks, vitreous hemorrhage, buckle malposition, and vortex vein damage). Results: Mean age was 64.11±7.91 years (range, 55-79 years) in Group 1 and 65.20±6.15 years (range, 56-80 years,) in Group 2. Mean age and gender were not statistically significantly different between the groups (p=0.508 and p=0.990, respectively). Etiological causes were revealed as myopia, peripheral retinal degeneration, pseudophakia, aphakia, trauma, and idiopathic. Etiological causes were not significantly different between the two groups (p>0.05, for all). Surgical complication rates were higher in Group 2, however, the differences were not statistically significant (p>0.05, for all). Anatomical success rates was similar between the two groups (80% in Group 1 and 79.5% in Group 2, p=0.956). Conclusion: The results of scleral buckling surgery with and without use of operating microscope were not significantly different; However, operating microscope should be used especially in presence of risk factors for scleral complications. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the results of scleral buckling (SB), pars plana vitrectomy (PPV) and combined scleral buckling and pars plana vitrectomy (SB+PPV) surgeries for the treatment of rhegmatogenous retinal detachment. Material and Methods: This study included cases (101 cases) who received surgical treatment due to primary rhegmatogenous retinal detachment in our clinic, between April 2006 and April 2010. According to surgery techniques, the cases were evaluated retrospectively and divided into three groups as SB, PPV and SB+PPV. The groups were evaluated for anatomical and functional success and encountered complications. Results: When the cases were evaluated with regard to their related factors, the ratios of myopia, pseudophakia, trauma, and aphakia were determined around 26.7%, 39.6%, 14.9%, and 3% respectively. After the first surgeries, anatomic success rates were determined about 54.9% in SB, 80.6% in PPV, 85.7% in SB+PPV group. After recurrent surgeries, anatomic success rates were obtained around 88.2% in SB, 91.7% in PPV, 100% in SB+PPV group. Functional success rates were found out 76.5% in SB, 72.2% in PPV, 78.5% in SB+PPV group. Cataract was the most frequent complication in PPV (52.6%) and SB+PPV groups (50%). The most frequent complication in SB group was determined as the recurrence of retinal detachment (45.1%). Conclusion: In our opinion the best results can be obtained when the appropriate surgical method was performed carefully with using of appropriate material for the treatment of rhegmatogenous retinal detachment. [ABSTRACT FROM AUTHOR]

Purpose: To examine the maculae of eyes with macula-off regmatogenous retinal detachment by optical coherence tomography (OCT) after scleral buckling surgery. Materials and Methods: Eighteen eyes of 18 patients with macula-off regmatogenous retinal detachment who had no trauma or other ocular pathologies were included in this prospective study. Scleral buckling surgery were applied to all patients. In addition to ophthalmologic examination, maculae were examined by OCT postoperatively on 1st, 3rd, 6th, 9th and 12th months. According to this, presence of subretinal fluid (SRF) on macula, its structure, persistence period, and its effect on visual acuity were evaluated. Results: SRF was detected in 9 (50%) patients by macular OCT following surgery. This fliud was as a single cyst in 5 eyes, multipl cysts in 1 eye and confluent SRF in 3 eyes. There was no difference according to age and sex between eyes with SRF and without SRF. Preoperative detachment period was longer in eyes with SRF. According to the preoperative and postoperative visual acuities on 1st, 3rd, 6th, 9th and 12th months, there was no statistical difference between eyes with SRF and without SRF, SRF was resolved completely after 4.1±2.3 (2-9) months. Conclusions: SRF detected after retinal detachment surgery may be related to longer detachment period preoperatively. It does not affect visual acuity negatively, and its spontaneous resolution may take months. [ABSTRACT FROM AUTHOR]

Macular hole is characterized by a total loss of retinal tissue involving fovea, and represented as a rare complication after retinal detachment repair. In this report we present a case of a macular hole which developed following scleral buckling surgery and its repair for bullous regmatogenous retinal detachment involving macula. [ABSTRACT FROM AUTHOR]

This work aims at comparing the predictions obtained from various mathematical tools including genetic algorithm (GA), real valued particle swarm optimization (PSOC) and discrete particle swarm optimization (PSOD) for buckling of composite cylindrical shells subjected to uniaxial compressive load. Fiber orientation (stacking sequence) was considered as a design variable, while the number of plies is considered constant. The accuracy of the predictions was compared and ranked based on statistical significance of the findings. Results suggest that both GA and PSOD is able to produce high quality solutions to the design problem, while the designs produced by PSOD is found to be statistically better than those found by GA. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to evaluate the complications of encircling scleral buckles used for retinal detachment surgery and the risk factors predisposing these complications. Material and Methods: The records of patients who had retinal detachment surgery with encircling band within the last 10 years were reviewed retrospectively for encircling band related complications. These cases were further analyzed for demographical and ophthalmological features that may predispose to these complications. Results: Of 2012 retinal detachment surgeries, encircling scleral buckle related complications were seen in 9 cases (0.45%). Four cases (44.4%) had degenerative myopia and 1 case (11.1%) had previous penetrating eye trauma. The mean period between surgery and the occurrence of complications was 67.6 (1 month- 30 years) months. Because of deeply located buckles; there were 3 cases (33.3%) of scleral and choroidal erosion and preretinal-vitreous hemorrhages at buckling area and 1 case of scleral perforation. Encircling scleral buckle migrated posteriorly or anteriorly in 3 cases (33.3%). There was a case of total extrusion of the buckle eroding conjunctiva, and a case of conjunctival erosion secondary to sutures of buckle. There was a recurrence of retinal detachment in only 1 of 7 eyes (14.2%) after extraction of the buckle. Conclusion: Although complications of encircing scleral buckling for retinal detachment surgery are rare, degenerative myopia may be a predisposing factor for this complication. These complications can be overwhelmed with early diagnosis and treated with buckle extraction. [ABSTRACT FROM AUTHOR]

With the development of industrialization, steel structures in our country, especially industrial structures, light housing structures, bazaar, car parks etc. have been widely used in the fields. In the use of lightweight and easily available box sections, undesirable local buckling problems occur especially in the joint areas. Especially when the dimensions of the joined box sections are different, the narrow section causes local buckling on the large section surface. In the study, the results of the box-section column-beam joint, which were experimentally analyzed in the literature, were verified using the ABAQUS program. Using verified numerical models; the number of models has been increased by using details with joint zone plate, side wrap plate and stiffening plate. By using the ABAQUS program, models with different joint details were analyzed under bending moment and the system behavior was tried to be determined. In the analyses made, it was seen that the most effective result was the case with the stiffening plate. [ABSTRACT FROM AUTHOR]

Steel members under the effect of axial compression are designed in such a way that there is no buckling. However, these elements should be strengthened in cases where the purpose of use of the structure changes or the building performance does not provide the desired strengths. In this study, four different strengthening were applied to increase the weak moment of inertia of the members by reference to the braces with a certain slender cross-section. Three of them are steel plate addition and the fourth is CFRP wrapping. One of the steel strengthening is welded and the other two are bolt supported strengthening. Strengthened test specimens were subjected to quasi-static cyclical axial loading with a prepared setup. As a consequence of the test, axial force-axial deformation curves were obtained. With the obtained data, bearing capacities, displacement capacities, buckling loads, energy dissipation capacities and ductility parameters are presented comparatively. As a result of the experiments, it was seen that the sample strengthened by welding the additional plate along the body caused the greatest increase in buckling strength compared to the reference sample, but it caused earlier failure in tensile. It was concluded that the contribution of the other samples to the compressive strength remained at low levels, but better performance could be achieved with improvements. [ABSTRACT FROM AUTHOR]

Single-angles are generally loaded parallel to their geometrical axes. And, their cross sections are not symmetrical to their principal axes. Even equal leg angles have only one symmetrical axis. Many loading types cause biaxial bending and axial force in these members. Since single-angles are slender members, they also need to be analyzed under the flexural buckling, lateral torsional buckling and local buckling effects. In this study, a calculation procedure is presented to analyze nominal loads of equal leg angle section beams loaded vertically to the beam axis. It is assumed that axial force is composed of constant and compressive force. Constant axial force is taken into consideration only for the uniform compressive stress and second degree effects caused in the cross section. By this way, only biaxial bending moments are left. The first yield, full plastic and critical lateral torsional buckling moments for biaxial bending is calculated with respect to the slenderness and the axial force. The nominal design force on the cross section among these moments is calculated according to the LRFD rules. Analysis procedure presented for constant axial load can also be used for general conditions of axial forces, by using an consecutive calculation procedure. [ABSTRACT FROM AUTHOR]

Cylindrical steel tanks are widely used to store variety liquids such as water, petroleum, and industrial chemicals. They also have been becoming widespread for cooling in nuclear power plants last years. Steel liquid tanks can be exposed during earthquakes and also they can cause great financial and environmental damage with their containing petroleum or other hazardous chemical liquid. The natural vibration periods of these tanks, which are important engineering works, are in the range of 0,1 s - 0,5 s. If there is no mechanism to absorption the maximum earthquake energy that occurs in this short period, the tank will resonate and damage will occur. For this study, deformations in cylindrical steel tanks were used for earthquake recording of 0.22 seconds since buckling occurred in a very short period. In addition, this time and earthquake values are ideal for nonlinear analysis because ANSYS Workbench "Explicit Dynamics" tool provides very good results in the dynamic analysis of structures under destructive and short-term forces. In order to provide the interaction between the water and the tank wall, the "Eulerian Body" mesh technique is preferred in "Explicit Dynamics" model. In the analysis, an open-top tank model, a conical model and a torisperical closed model were used and the analyzes were repeated for three different tank wall thicknesses. Depending on the shell thickness of the tank and the shape of the tank roof, the causes of deformation and buckling were examined. As a result of the analysis, it was seen that torispherical closing of the cylindrical steel liquid tanks reduced deformation and buckling. [ABSTRACT FROM AUTHOR]

In this study, optimization of space steel frames exposed to seismic loads was carried out by taking into consideration both materially and geometrically nonlinear behaviours via the ANSYS packed program. By taking into account the buckling estimations, the buckling constraints were applied to the optimization technique. For the nonlinear behaviour of the material, the bilinear cinematic hardness model was used and the buckling formulation given in TS 648 was taken in the solutions. For a dynamic solution technique, Newmark method and for the nonlinear solution algorithm, Newton-Raphson methods were used. Solutions were found by preparing subroutine in APDL (Ansys Programming Design Language) coding language of ANSYS packed program. [ABSTRACT FROM AUTHOR]

Displacements take considerable values as the thicknesses of the cross-sections of box girder bridges decrease. Because of that reason, second order effects need to be taken into account in order to make an accurate analysis. In this study, application fields of a rectangular and a curved shell finite element are extended by adding second order effects to the formulations. Mass matrices of these elements are obtained to find the natural vibration periods of straight and curved axis box girder bridges, open section bridges and circular plates. For the analysis of box girder bridges with cross-sectional diaphragms, membrane finite elements can be used in order to define the cross-sectional diaphragm effect. For this purpose, the formulation of a general quadrilateral membrane finite element is given and the mass matrix of the element is obtained to be used in dynamic analysis. Both rectangular and curved shell finite elements which are used here have seven degrees of freedom per node. General quadrilateral membrane finite element which is selected to be used as cross-sectional diaphragms has three degrees of freedom per node which are two translations and one inplane rotation and its formulation is based on displacement superposition. Stiffness and mass matrices of the rectangular shell finite element are obtained by using closed form formulation while Gauss integration rule is used for the stiffness and mass matrices of curved shell and quadrilateral membrane finite elements. The analysis of box girder bridges using matrix displacement method is described and determination of buckling loads and natural vibration periods of the systems are explained briefly. The part of the bridge between two cross-sections composed of a number of finite elements is called a macro-element. Stiffness, loading and mass matrices are established independently for different macro-elements and system stiffness, loading and mass matrices are obtained by the combination of these matrices. Three examples are given in order to illustrate the work done in this study. In the first example, a circular plate is solved for fixed and clamped support conditions and buckling loads are obtained for both cases. The results are close to the results of analytical solution and the buckling load of the clamped circular plate is found to be 3.5 times of the buckling load of the circular plate with fixed supports. The second example is a reinforced concrete box girder bridge with straight axis. It is solved according to the first and the second order theories under its own weight and vertical displacements of the midspan are compared with each other. It is seen that the increment of the vertical displacements is only about 1% which is because the thicknesses of the cross-section are not considerably small. It can be said that the increment ratio increases as the thicknesses decrease. Then, the same problem is considered to have two cross-sectional diaphragms at the support cross-sections and four diaphragms, two at the supports and two at the span cross-sections. It is solved under antimetric vertical point loads subjected at the midspan and vertical displacements and inner forces are compared with each other. It is concluded that adding diaphragms decreases both vertical displacements and inner forces due to warping. Also, the first four natural vibration periods of the bridge with and without cross-sectional diaphragms are obtained and it is observed that natural periods of the system decrease by the usage of diaphragms. A curved reinforced concrete box girder bridge which is the last example, is solved under its own weight according to the first and the second order theories and first four natural vibration periods are obtained.The increment of the vertical displacements of the midspan cross-section is about 1%. The conclusions obtained are as follows: Buckling loads of circular plates are close to the values which are obtained analytically. Second order effects are not considerable for reinforced concrete box-girder bridges because of their cross-sectional thicknesses. Cross-sectional diaphragms reduce the vertical displacements and inner forces of the bridge due to warping. Natural vibration periods of box-girder bridges decrease by the usage of cross-sectional diaphragms [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the results of pars plana vitrectomy (PPV) performed for the retinal detachments due to high myopia. Materials and Methods: Twenty-one eyes of 20 patients (12 male, 8 female; mean age: 50.2 years) who underwent encircling scleral buckling and PPV for retinal detachment and proliferative vitreoretinopathy due to high myopia (more than six diopters) were evaluated retrospectively. The patients were assessed for anatomical success, functional success and post-operative complications. Results: Patients were followed-up for average 6 months. In all of the eyes anatomical success was achieved after the operation. In none of the eyes, recurrent retinal detachments occurred. The visual acuity improved in 76% of eyes and remained the same in 24% of eyes. Postoperative complications were transient ocular hypertension, migration of silicon oil into the anterior chamber, silicon oil emulsification and existence of liquid perfluorocarbon bubble in the anterior chamber. Conclusion: Encircling scleral buckling and PPV is very effective both anatomically and functionally in patients with retinal detachments due to high myopia. [ABSTRACT FROM AUTHOR]

In this study, mechanical behaviour of quasi-unidirectional (quasi-UD) non-crimp fabric (NCF) reinforced composite plates with pinned joints was investigated experimentally. Composite laminates with three different cross-ply and three different quasi-isotropic layups were manufactured with vacuum assisted resin transfer moulding (VARTM) method. The pin-bearing tests of the specimens were completed according to ASTM D5961 standard. Test results were compared with a different material system and joint configuration. Finally, the cross-sections of damaged areas were inspected with optical microscopy. [ABSTRACT FROM AUTHOR]

Under the construction of German Mine Hunter Consortium (Abeking&Rasmussen and Lürssen), Istanbul Shipyard/Pendik is building Aydin Class Mine Countermeasures (MCM) Vessels for Turkish Navy. Aydin Class Mine Countermeasures (MCM) Vessels distinct from the other world navies because of their hull made of austenitic stainless steel. Nowadays, German, Italian and Canadian navies use this type of steel for ship hulls. Austenitic stainless steel has many advantages, like resistant to the corrosion of sea water, high yield point and non-magnetic structure. But these metals are having also disadvantages, like poor heat conductivity and high thermal expansivity. These disadvantages create more distortions than normal steels in welding conditions. Fittings of welded structure are very important section in shipbuilding, so geometry of welded structure need to be accurate. For straightening of distortions, flame straightening method is widely using in shipbuilding industry. Nowadays for quality products it is necessary to reduce price. Straightening of distortions via flame straightening method is more time, manpower and material consuming. So improving of straightening of distortions will be beneficial for budget of government. The aim of this thesis is to show benefits of usage of Thermal Tensioning Technique as a method of straightening of distortions for Aydin Class Mine Countermeasures (MCM) Vessels which are built at the Istanbul Shipyard/Pendik. Straightening of distortions via Thermal Tensioning Technique is examined for ship building industry as a preventing method with many academic researches. The stiffened panel made of austenitic stainless steel is used in the experiment of the Strathclyde University/ Scotland. In specific condition under gas protection weld (MIG), thermal camera is used for distribution of heat, thermo couples are used for temperature measurement and laser appliance is used for distortion measurements. This paper focuses on the transient temperature fields created by the large heat inputs from arc welding which is the driving force for distortion in the plates. The use of a thermal imaging camera allows the thermal fields to be viewed on a whole-field basis. The use of a welding rig in this kind of investigation is essential as it allows parameters to be kept constant throughout. The moveable track is controlled by stepper motors such that the travel speed of the weld can be adjusted to a tenth of a millimeter per second. The torch is held static while the plate is pulled along at a constant speed by a series of pulleys and small stepper motors. The welding machine was connected to the computer and so all parameters could be entered via the computer so that all the variables could be controlled. The camera was held in place with scaffolding and the tripod for the camera fixed to a bracket that allowed movement in all directions. The CCD thermal imaging camera used here was the ThermaCam SC500 from FLIR systems. The camera is able to provide thermo graphic images in the infrared spectrum from 3 to 12μm. Following initial tests with austenitic stainless steel plates the amount of background radiation reflected from the plate to the camera was seen to be high. This led to the painting of the plates with a high emissivity, two-part zinc silicate primer made up in two parts. To verify thermal images thermocouples were also present at distances of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100mm. The laser appliance is used for distortion measurements. All of austenitic stainless steel plates are scanned before welding and again after welding. The data was used to compare the distortion effects under different restraint conditions.… [ABSTRACT FROM AUTHOR]

In recent years, using cold-formed steel members as structural and complementary structural elements has become very popular. The fact that these elements have thin wall thicknesses (t=6 mm) due to their manufacturing characteristics makes the buckling and torsional strengths critical in designing these elements. In this study, the flexural strength of clawed C profiles used in the construction industry in our country will be calculated with TS EN 1993-1-3, AISI S100-16, and DSM. After determining the strengths of 72 selected profiles with these design methods, a comparison was made between them, and the performance of the methods was tested. The differences between the methods are shown on the graph. [ABSTRACT FROM AUTHOR]

Steel structural elements face local buckling problems under both bending and axial compressive loads. It is possible to rectify this buckled element by applying heat treatment method instead of replacing it with a new one. This retrofit process can quickly be performed to repair locally buckled structural elements in emergency situations such as earthquakes. However; heat treatment technique is addressed as temporary retrofit due to the decrease in the stiffness of the original material and the existence of permanent geometrical imperfections implemented in the repaired structural element. Buckling behavior of the repaired element truely will be different from the original element because of these effects. This study aims to change this temporary retrofit into a permanent one. Following the application of heat treatment techniques, glass fiber reinforced polymers have been bonded to surfaces to investigate the different bonding compositions for strengthening purpose. The outcomes of this experimental study are evaluated to validate the proposed method. [ABSTRACT FROM AUTHOR]

This study presents an experimental investigation into the seismic retrofit of tubular steel braces using carbon fiber reinforced polymer (CFRP) members. CFRP retrofitting of net sections for compact tubes are proposed for delaying potential local net section failure. A total of almost full-scale three (TB-1, TB-2, and TB-3) compact steel tubular specimens were designed per AISC specifications, constructed, and cyclically tested to fracture. Retrofitted braces, when compared to the reference specimen, developed fuller hysteretic curves. Increase in cumulative hysteretic energy dissipation and the elongation in fracture life in the specimen retrofitted with CFRP plates and CFRP sheet wraps at net sections are observed during testing. This resulted in a maximum of 82.5% more dissipated energy for compact tube specimens. Also, this retrofit provided a longer experimental fracture life (maximum 59% more). Due to fracture initiation during the last cycles, significant reductions in strength and stiffness have been obtained. No significant change (maximum 10%) in the brace stiffness was observed, which could be desirable in seismic retrofit applications. Pushover analysis per FEMA 356 for the bare specimen shows that FEMA does not represent actual brace behavior in the compression side although pushover and experimental results are in good agreement in the tension side. [ABSTRACT FROM AUTHOR]

Purpose: To compare scleral buckling, pars plana vitrectomy and their combination for the treatment of pseudophakic retinal detachment (PRD) Materials and Methods: This is a retrospective evaluation patients who were treated for PRD between January 01 and March 06 in Department of Ophthalmology at Gazi University Faculty of Medicine. Patients with proliferative diabetic retinopathy, trauma history, proliferative vitreoretinopathy (PVR) higher than grade B, macular hole, redetachment were excluded from the study. The patients were grouped according to the type of surgical intervention, group I received scleral buckling (SB), group II pars plana vitrectomy (PPV) and group III received a combination treatment of both (SB+PPV). Preoperative and postoperative completely ocular examination, the type of surgical technics, type of intraocular tamponade used, intraoperative and postoperative complications were analyzed. Kruskal-Wallis H Test and Wilcoxon Test was used to compare preoperative and postoperative characteristics of 3 groups using SPSS 13 statistical software. Results: Sixty four eyes of sixty three patient was included in the study. There were 32 (50%) eyes in group I, 10 (15.7%) eyes in group II and 22 (34.3%) eyes in group III. Preoperative mean best corrected visual acuity (BCVA) (LogMAR) were 1.8, 1.5, 2.3 in groups I, II and III respectively (p<0.05). At final visit, postoperative mean BCVA were 0.8, 1.5, 2.3 in groups I, II and III respectively (p>0.05). Reattachment with single surgery was achieved in 71.9% eyes in group I, 80% eyes in group II and 81.8% eyes in group III (p>0.05)). There was no statistically significant difference between the three groups in postoperative complications except intraocular pressure Conclusion: In our study; the highest anatomical success was achieved in the SB+PPV group and the lowest anatomical success was in the SB group, and the highest functional success was achieved in the PPV group and the lowest functional success was in the SB+PPV group. [ABSTRACT FROM AUTHOR]

Ductile concentrically braced frames (CBFs) are commonly used seismic force-resisting systems in seismic regions. The capacity design approach described in the state-of-the-art seismic codes of the US, Canada, and Turkey defines a design procedure for columns and girders via two structural analyses that intend to capture the nonlinear behavior of CBFs while assuming braces in different stories undergo yielding or buckling, simultaneously. It would be, therefore, befitting to question the validity of the anticipated mechanism controlling CBF design considering limited studies in the literature. In addition to chevron and two-story Xbraced frame configurations, an alternative design approach is proposed without changing the current habits in the industry. The present study aims to investigate whether or not the capacity design approach adopted by the leading seismic codes is consistent with the nonlinear behavior of CBFs via pushover analyses and time-history analysis. For the proto-type CBFs, peak and residual inter-story drift ratios were compared as well as ductility demands of braces. In conclusion, it is found that mechanism scenarios stimulated in current seismic codes are unlikely to occur under an earthquake event and the proposed balanced design approach provided significant reductions on seismic demands, only with an 8% increase in weight. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the causes of the landslide occurred on 18 February 2013 at the NW- facing slope of the Harmandalı waste disposal site located in İzmir-Çiğli and the reactivation potential of the same circular slip surface. In the light of the geological and geotechnical studies resumed in September-2016; the reactivation potential has been evaluated. An embankment (a barrier) was built as a protection structure in front of the slopes of solid waste in 2010. It was determined from the readings in the inclinometer boreholes drilled right after the landslide that the sliding slowed down gradually after the initial landslide. A 64.5 mm displacement occurred in horizontal direction towards NW along the circular slip surface passing through the high plasticity clay band located under the embankment. This movement caused cracks on the walls of the administration buildings, disruption of the main connection road, and deformation such as buckling indicating the effect of compression within the embankment. The longitudinal cross-section showing the sliding mechanism has been prepared based on the pressuremeter tests and the readings taken from the inclinometer boreholes drilled at different locations in March-2013 and September-2016. In addition, the engineering properties of high plasticity clays (CH), which are the weathering products of the andesitic tuffs that cause sliding, have been investigated. [ABSTRACT FROM AUTHOR]

By the recent earthquakes occurred in our country, the utilization rate of the steel structure especially in the industrial structure has increased when compared to concrete structures. But when the places where steel construction preferred are considered; either architectural and statically project or technical infrastructure which participates in production and mounting steps can't render service to country-wide equally. For this reason, design, manufacturing and application services are tried to be resolved by the local facilities. This situation is easily accessible in the building design and the hallow-section profiles were processed foreground. But hallow-section profiles bring local buckling problems under the effect of shearing force and bending loads together depending on their section geometry. Local buckling problems observed in frame systems formed by hollow-section profiles cause unpredictable capacity losses in the problems and lead to a risk for industrial structures. That's why, numerical analysis programs as well as the appropriate management and interpretation of solution algorithms of these programs are crucial since it is possible to predict structural weaknesses in the design of buildings resistant to earthquake in Turkey where the seismic activity is widespread and thus designing buildings. In this present study, a sample which is completed experimental analysis is numerically modeled with ANSYS and analyzed. The numerical model which is verified by experimental analysis has tried to capture the real behavior and solution was analyzed for commands about different meshing techniques on the loading apparatus. Within this scope, the obtained results are compared and the effects of mesh technique and mesh quality on joint behavior is tried to be shown. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the factors affecting anatomical and functional success in the surgical management of the retinal detachment with giant retinal tears (GRT). Materials and methods: In this study, medical records of 75 eyes of 75 patients who surgically treated due to GRT were reviewed retrospectively. Pars plana vitrectomy (PPV) was performed in 53 patients and PPV + scleral buckling in 22 patients. Results: Patients were divided into pairwise groups considering the presence of preoperative PVR, trauma history, macular detachment and recurrence. Final best-corrected visual acuity (BCVA) levels and postoperative visual gain were significantly lower in the groups with these factors. The type of surgical procedure has no significant effect on final BCVA and postoperative visual gain. There were statistically significant negative correlations between the GRT size, mean duration of complaints and the levels final BCVA and postoperative visual gain. Trauma history, PVR, macular detachment, greater tear size were the prognostic factors associated with poor final BCVA and visual gain (three- way ANOVA). PVR, macular detachment, greater tear size were found to be risk factors for the recurrence (logistic regression analysis). Conclusions: Mean duration of complaints, tear size, trauma history, PVR, macular involvement were considered as the prognostic factors affecting the success of surgical treatment of the retinal detachment with GRT [ABSTRACT FROM AUTHOR]

Thin steel plate shear walls are very effective and economical lateral load-resisting systems. A thin steel plate shear wall is composed of vertical steel plates which are named as infill panels and columns and beams connected to steel panels. The beam-to-column connections may be either full moment-resisting and partially moment-resisting (semirigid) joint types or simple joint type. Infill steel panels are generally attached to the surrounding frames by either fillet welds or bolts. Utilization of steel plate shear walls began in early 1970's. Initially, stiffened steel shear walls were used in Japan in new construction and in the USA for seismic retrofit of the existing buildings as well as in new buildings. Early steel shear walls have been designed such that shear buckling of the infill plate should not be occurred. Thus, in order to prevent the shear buckling of the steel panels vertical and horizontal stiffener members attached to the surfaces of the steel infills were used. In that design philosophy, post-buckling behavior of the steel panel was neglected. In this study, an experimental research which includes one, 1/3 scale, one-storey, single bay test specimen, so-called SW-A-H is performed under cyclic loading in order to understand the cyclic response of thin steel plate shear wall systems. The test specimen used for this purpose consists of a boundary frame and thin steel plate which is connected to boundary frame members on all edges. Infill plate is 0.50mm thick and has a height of 900mm and width of 1520mm. Self drilling screws with 5.5mm diameter are utilized to provide the connection between the infill and surrounding frame members. Also, a fish plate welded to the flange of each frame member is used. In this experimental study, the specimen is tested in accordance with the ATC-24, Guidelines for Cyclic Seismic Testing of Components of Steel Structures, by Applied Technology Council. In accordance with ATC-24, the number of cycles with a peak deformation less than yield displacement were eighteen. The number of cycles with peak deformation that is equal to yield displacement are three. After the cycles with peak deformation larger than yield displacement, the increment of yield displacement was applied to the peak displacement for each step. In order to determine the material properties of the infill panel and beam end plates tension coupon tests were conducted at Construction Materials Laboratory of ITU. The coupons were cut in two orthogonal directions from the infill plate. While six coupons were used for the infill panels three coupons were taken for the beam end plates. Cyclic test of the specimen was performed at Structural and Earthquake Engineering Laboratory of ITU.… [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical features, surgical methods and results of surgery in retinal detachments (RD) developing after refractive lens excange (RLE) and phacic intraocular lens (PIL) implantation in highly myopic eyes. Materials and Methods: Nine eyes of 7 patients who had rhegmatogenous retinal detachment after RLE and PIL implantation for high myopia were included in the study. Best corrected visual acuities (BCVA), duration between the refractive surgery (RS) and retinal detachment (RD), vitreoretinal findings, anatomic and functional success (at least 2 lines increase in visual acuity) were evaluated. Results: Of the patients 4 were female, 3 were male. The mean age of 7 patients was 38.14±9.42. Posterior chamber phacic intraocular lens was implanted in 3 (33.3%) eyes, anterior chamber phacic intraocular lens was implanted in 1 (11.1%) eye and RLE was performed in 5 (55.5%) eyes. Mean interval between RS and RD was 63.66±42.3 months. Preoperative mean BCVA was 20/25000 (0.001) median proliferative vitreoretinopathy grade was B (A-D2). Eight (88.8%) eyes had macular detachment. Scleral buckling was performed in 1 eye, pars plana vitrectomy±scleral buckling was performed in 8 eyes. The mean follow up was 13.77±5.58 months after surgery. Retinal attachment was achieved with single operation in 6 (66.6%) eyes, with two surgeries in 2 (22.2%) eyes, and with three operations 1 (11.1%) eye. Final anatomical success rate was 100%. Functional successs was achieved in 7 (77.7%) eyes. Conclusion: Retinal detachments following refractive surgery represent a complicated group of retinal diseases. However, successful anatomical and functional results can be obtained if appropriate treatment methods are prefered. [ABSTRACT FROM AUTHOR]

Purpose: To assess anatomic and functional results after surgical management of retinal detachments from inferiorly located breaks. Materials and Methods: Twenty eyes of 19 patients (8 female, 11 male) with retinal detachment due to inferiorly located retinal breaks were included in this study. Eight of the eyes without significant proliferative vitreoretinopathy (PVR) underwent conventional surgery with encircling scleral band and local buckle, while another 8 eyes with grade C1 or worse PVR underwent pars plana vitrectomy (PPV) and intravitreal tamponade in addition to encircling scleral buckle. Four eyes that had been operated on in other centers but showed recurrence were also re-operated using PPV in our clinic. The results of our surgical intervention were evaluated in terms of anatomy and functionality. Results: Conventional retinal surgery resulted in anatomic success in 6 out of 8 eyes with a single operation. Another 2 eyes were further operated on to attach the retina. Anatomic success was achieved in 7 of 8 eyes that underwent a combined operation in the first attempt, and one other in the second attempt. In the eyes that were referred to our clinic for re-operation, anatomic success was obtained in 2 of the 4 eyes with one operation, and in other one with a further operation. No success was achieved in the fourth eye. Overall, retinas were found to be attached in 19 eyes (95%), while visual acuity improved in 14 eyes (70%) and remained the same in 6 eyes (30%) at the final examination. Conclusion: In eyes with retinal detachments with inferiorly located retinal tears, conventional surgery seems to suffice in eyes without significant PVR, while scleral buckling combined with PPV is appropriate for anatomic and surgical success in eyes with significant PVR. [ABSTRACT FROM AUTHOR]