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Highlights • Tensile behaviour of different GFRP laminates under elevate temperatures has is investigated. • Laminates with continuous unidirectional fibers showed the best tensile performance. • Laminates with chopped strand fibers showed the weakest tensile performance. • Laminates with continuous woven fibers performed better than chopped strand and weaker than unidirectional laminates. Abstract This study was aimed at gaining an improved understanding of the behavior of glass fiber-reinforced polymer laminates at elevated temperatures by means of testing laminate specimens with unidirectional, woven, and randomly distributed (chopped strand mat) fibers. The testing parameters were temperature, the type of fiber, and the thickness of the laminates. The failure modes of the specimens and their elasticity moduli at ambient temperature were investigated, and analysis of variance was conducted to determine the contribution of each parameter to the behavioral test results. The findings showed that among the parameters, an increase in temperature exerted the strongest effect on the specimens. The unidirectional laminate specimens exhibited the best performance, maintaining nearly 40% of their loading capacity at 550 °C. At this temperature, the woven laminate specimens could not carry any tensile load, and at 400 °C, the laminate specimens containing randomly distributed fibers lost all their strength. [ABSTRACT FROM AUTHOR]

• The effects of UV, moisture and elevated temperature on mechanical properties of GFRP pultruded profiles have been studied. • Different cross-sections were used to study the effect of profile type. • Effect of conditioning on different failure modes were investigated. • Regression models have been developed to predict the mechanical properties retentions. The present research examines the effects of UV radiation, moisture and elevated temperature on the mechanical properties of GFRP pultruded profiles. Flexural, compressive and tensile properties of different GFRP sections were studied after they were exposed for 1000, 1500, 2000 and 3000 h to UV radiation and water vapour condensation cycles. Mechanical tests, including three-point bending, compression and tension tests, SEM analyses, and statistical studies were conducted to gather comprehensive results. The results showed that the mechanical properties of various GFRP sections generally decreased with the duration of conditioning: however, the rate of the decrease that was only slight up to 1000 h, increased rapidly during 1000–2000 h, and again it was slow during 2000–3000 h. The maximum reductions were 34%, 28% and 23% after exposure to 3000 h cycles for bending, tensile and compression tests, respectively. In the bending tests, where inter-laminar shear failure controls ultimate strength, the degradation was greater compared to the situation where fibres fracture controls the failure. Further, regarding the cross-section parameter, it was concluded that the thickness and perimeter are the effective factors; the thinner the sample and the larger the perimeter, the greater is the reduction. However, the maximum effect of the cross section in terms of thickness and perimeter did not exceed 13% among all sections. [ABSTRACT FROM AUTHOR]

The performance of beam-to-column connections is a key factor in the behaviour of moment-resisting frames (MRFs) under fire conditions. In this work, the behaviour and failure mechanisms of a half-scale 3D frame, composed of single-bay, single-storey MRFs and Braced Frames, in two perpendicular planes, equipped with 6 mm thick flush end-plate connections, under fire conditions was studied. A 'scaled' ISO 834 standard fire curve was followed during fire loading of the frame. The maximum reached temperature was 1100 °C. The temperatures of the elements of frames were measured at 2-minute time intervals. The rotations of the connections and the deflections of the MRFs' beams at these time points were worked out using an image processing technique. Furthermore, the effect of the ductility of connections was investigated by comparing the results of this study with those of a previous one in which less ductile connections were used. The results showed that the connections used in this study could sustain large rotations of up to 0.7 radian and endure 65 min under fire. Moreover, it was found that using flexible connections (connections with thinner end-plates) enhances the 'robustness' of moment frames in fire. • Scaled experimental models can be used to predict behaviour of structures in fire. • Image processing can be used for measuring deformations and rotations in fire tests. • Thickness-induced flexibility of thinner end-plates increases structural robustness. • Thinner end-plates reduce risk of over-stretching of bolts & structural collapse. • Simulated 'real fire' in this work triggered all forms of failure but overall collapse. [ABSTRACT FROM AUTHOR]

This study investigates the effect of Thermal cycles on the mechanical properties of GFRP pultruded profiles with different geometries. Bending specimens consisted of I-shaped and U-channel profiles that were tested in three-point bending along their both principal weak and strong axes, whereas box profiles and laminates were used in compression and tension tests, respectively. Each specimen was exposed to a range of thermal cycles, between −20 °C and 20 °C. The failure modes of the profiles were closely investigated at both major and minor scales. Results were analyzed using ANOVA to determine the influence of each factor and a model was developed to predict the strength retention of profiles after exposure to thermal cycles. The results showed that the thermal cycles have a significant effect on the strength of the resin and a minor effect on the strength of the fibers. Bending specimens experienced a lower strength loss along their principal weak axis than that along their strong axis after conditioning. Tension specimens performed better in comparison to compression specimens in terms of strength retention after thermal exposure. These results are expected to contribute significantly toward the understanding of the influence of thermal cycles on the behavior of GFRP profiles. [ABSTRACT FROM AUTHOR]

Abstract This study investigates the flexural and impact behaviour of GFRP laminates after exposure to elevated temperatures. The effect of fibre's length and orientation, laminate's thickness, and exposure time is studied. A total number of 540 tests in terms of three-point bending and Charpy impact tests were conducted to obtain the mechanical properties. In addition, SEM analyses were carried out to investigate the degradation mechanisms. Finally, statistical study was conducted to investigate the contribution of each variable and develop probabilistic models using ANOVA and linear Bayesian regression method. The results showed that generally the flexural and impact properties of GFRP laminates decrease by increasing the temperature and time of exposure as well as decreasing the laminates' thickness. It is also observed that laminates with unidirectional fibres have the best performance under elevated temperatures, while laminates with randomly distributed fibres are the most vulnerable type. The performance of laminates with woven fibres are almost between those two other types. However, all types of the laminates lost almost all their flexural strength and impact energy absorption capacity at 300 °C. [ABSTRACT FROM AUTHOR]

• Mechanical properties of various GFRP pultruded profiles under SWSSC is investigated. • Effect of initial exposure to UV radiation and moisture before subjecting to SWSSC is studied. • Samples initially exposed to UV and moisture show higher reductions after exposure to SWSSC. • Profiles with interlaminar shear failure are more vulnerable than profiles with bending failure. In this research, the mechanical properties of various glass fibre reinforced polymer (GFRP) pultruded profiles exposed to seawater sea sand concrete (SWSSC) and its combination with UV radiation and water vapour condensation were studied. The effect of different conditions, duration of conditioning, and the profile cross-section configuration on the mechanical properties were investigated. Three-point bending, tension, and compression tests were carried out to obtain the mechanical properties, including flexural, tensile and compressive strengths and tensile elastic modulus. Furthermore, in order to scrutiny the mechanisms and extent of damage, scanning electron microscopy (SEM) was carried out on the test samples before and after the exposures. Finally, regression models were derived according to the experimental data to describe the mechanical properties of profiles after exposure to the aggressive environments used in this study. The maximum reductions of about 30%, 33% and 46% were observed in three-point bending, tensile and compressive tests, respectively amongst all samples when exposed for 90 days to simulated SWSSC. These reductions increased for the same sections to 52%, 47%, and 50% when the GFRP profiles were pre-exposed for 3000 h to UV radiation and moisture before exposing for 90 days to simulated SWSSC. [ABSTRACT FROM AUTHOR]

This study investigates the tensile properties of various GFRP laminates after exposure to elevated temperatures. Fiber configuration, exposure temperature and laminate thickness were considered as the test variables. A total number of 180 specimens were tested in tension to obtain the mechanical properties of GFRP laminates. Alongside the mechanical tests, SEM analyses were conducted on selected samples before testing to investigate the resin, fiber, and their interface damages. Regardless of the sample type, it was generally observed that the reduction rate in the tensile strength increased with an increase in the exposure time and a decrease in the laminates' thickness. The results of tensile tests after exposure to elevated temperatures showed that the laminates with continuous unidirectional fibers performed the best, laminates with chopped strand randomly distributed fibers performed the worst, and the performance of the laminates with woven continuous fibers was somewhere in between. The maximum tensile strength reductions for the unidirectional and woven laminates were about 50% after exposure to 300 °C, whereas random chopped strand laminates lost almost all of their load carrying capacity under this exposure condition. [ABSTRACT FROM AUTHOR]

Background Neuroglial cysts are rare intracranial lesions that are believed to originate from the sequestration of neural tube lining during embryogenesis. They can present anywhere within the neuraxis; however, their most common location is the frontal lobe. Cerebellopontine angle (CPA) neuroglial cysts are extremely rare and, to the best of our knowledge, there are no previous reports of a neuroglial cyst arising from cranial nerves. Case Description The current study presented a male adolescent with the reoccurrence of an intracranial cyst with symptoms of diplopia and facial numbness primarily treated as CPA arachnoid cyst with fenestration of the cyst 12 months prior to admission to our center. Different magnetic resonance imaging sequences showed a thin-walled extra-axial cyst at the right CPA without gadolinium enhancement. Direct visualization of the lesion revealed a cyst arising from the fifth cranial nerve sheath compressing the surrounding structures. The cyst was fenestrated, and a biopsy was taken from the cyst wall. The pathological analysis, along with specified histological markers, indicated the neuroglial nature of the cyst. Conclusions The rising of a neuroglial cyst from the nerve sheath is a finding that brings other possible origins of neuroglial cysts into consideration. [ABSTRACT FROM AUTHOR]

Objectives The endoscopic approach increasingly is used to treat third ventricular colloid cysts. Our objective was to assess the results of endoscopic resection of colloid cysts of the third ventricle. Methods A retrospective study was designed, and a series of 112 consecutive patients (76 male, 36 female) with third ventricular colloid cyst treated by endoscopic surgery was undertaken. Results We found that the most common clinical presentations in patients with third ventricular colloid cyst were headache, vomiting, and impaired vision. Complete resection was obtained in majority of patients (92%). Meningitis, hemiparesis, and memory deficits occurred most commonly as postoperative complications. Conclusions High rates of complete resection of third ventricular colloid cysts, with low morbidity and mortality, are possible with an endoscopic approach. The results of this study support the role of endoscopic resection in the treatment of patients with third ventricular colloid cysts as a safe and effective modality and show how endoscopic resection of third ventricular colloid cysts can produce favorable results. [ABSTRACT FROM AUTHOR]