Flexural Behavior of Natural Hybrid FRP-Strengthened RC Beams and Strain Measurements Using BOTDA.

Experimental and finite element analysis results of reinforced concrete beams under monotonic loading were presented in this study. In the experimental program, one beam was tested in an as-built condition. The other two beams were strengthened using natural hybrid FRP layers in different configurations. The natural hybrid FRP composite was developed by using natural jute FRP and basalt FRP. One of the most appealing advantages of natural fiber is its beneficial impact on the environment, which is necessary for the sustainability recognition as an alternative to synthetic FRP. The hybrid FRP was applied to the bottom concrete surface in one beam, while a U-shaped strengthening pattern was adopted for the other beam. The flexural behavior of each beam was assessed through strain measurements. Each beam was incorporated with conventional strain gages, as well as the Brillouin Optical Time Domain Analysis (BOTDA) technique. BOTDA has its exclusive advantages due to its simple system architecture, easy implementation, measurement speed, and cross-sensitivity. The experimental results revealed that the beam strengthened with the U-shaped hybrid FRP composite pattern had a better flexural response than the other counterpart beams did both in terms of peak loads and maximum bottom longitudinal steel bar strains. Beams B-01 and B-02 exhibited 20.5% and 28.4% higher energy dissipation capacities than the control beam did, respectively. The ultimate failure of the control beam was mainly due to the flexural cracks at very low loads, whereas the ultimate failure mode of FRP composite-strengthened beams was due to the rupture of the hybrid FRP composite. Further, strain measurements using BOTDA exhibited similar patterns as conventional strain gage measurements did. However, it was concluded that BOTDA measurements were substantially influenced by the bottom flexural cracks, ultimately resulting in shorter strain records than those of conventional strain gages. Nonlinear structural analysis of the beams was performed using the computer program ATENA. The analytical results for the control beam specimen showed a close match with the corresponding experimental results mainly in terms of maximum deflection. However, the analytical peak load was slightly higher than the corresponding experimental value.

Surface-Mounted Bare and Packaged Fiber Bragg Grating Sensors for Measuring Rock Strain in Uniaxial Testing.

The paper explores the possibility of using high-resolution fiber Bragg grating (FBG) sensing technology for on-specimen strain measurement in the laboratory. The approach provides a means to assess the surface deformation of the specimen, both the axial and radial, through a chain of FBG sensor (C-FBG), in a basic setup of a uniaxial compression test. The method is cost-effective, straightforward and can be commercialized. Two C-FBG; one was applied directly to the sample (FBGBare), and the other was packaged (FBGPack) for ease of application. The approach measures the local strain with high-resolution and accuracy levels that match up to the existing local strain measuring sensors. The approach enables the evaluation of small-strain properties of the specimen intelligently. The finite element model analysis deployed has proven the adaptability of the technique for measuring material deformation. The adhesive thickness and packaging technique have been shown to influence the sensitivity of the FBG sensors. Owing to the relative ease and low-cost of instrumentation, the suggested method has a great potential to be routinely applied for elemental testing in the laboratory.

Laparoscopic Heller myotomy and anterior Dor fundoplication for achalasia cardia in Malaysia: Clinical outcomes and satisfaction from four tertiary centers.

BACKGROUND: To evaluate the clinical outcomes and satisfaction of patients following laparoscopic Heller myotomy for achalasia cardia in four tertiary centers. METHODS: Fifty-five patients with achalasia cardia who underwent laparoscopic Heller myotomy between 2010 and 2019 were enrolled. The adverse events and clinical outcomes were analyzed. Overall patient satisfaction was also reviewed. RESULTS: The mean operative time was 144.1 ± 38.33 min with no conversions to open surgery in this series. Intraoperative adverse events occurred in 7 (12.7%) patients including oesophageal mucosal perforation (n = 4), superficial liver injury (n = 1), minor bleeding from gastro-oesophageal fat pad (n = 1) & aspiration during induction requiring bronchoscopy (n = 1). Mean time to normal diet intake was 3.2 ± 2.20 days. Mean postoperative stay was 4.9 ± 4.30 days and majority of patients (n = 46; 83.6%) returned to normal daily activities within 2 weeks after surgery. The mean follow-up duration was 18.8 ± 13.56 months. Overall, clinical success (Eckardt ≤ 3) was achieved in all 55 (100%) patients, with significant improvements observed in all elements of the Eckardt score. Thirty-seven (67.3%) patients had complete resolution of dysphagia while the remaining 18 (32.7%) patients had some occasional dysphagia that was tolerable and did not require re-intervention. Nevertheless, all patients reported either very satisfied or satisfied and would recommend the procedure to another person. CONCLUSIONS: Laparoscopic Heller myotomy and anterior Dor is both safe and effective as a definitive treatment for treating achalasia cardia. It does have a low rate of oesophageal perforation but overall has a high degree of patient satisfaction with minimal complications.

A case of laparoscopic resection of myxoid liposarcoma of the greater omentum

@#Primary omental liposarcoma is a rare clinical entity with less than 20 cases being reported in the literature. Laparotomy has been the traditional approach for resection, with no reports of laparoscopic resection. A 39-year-old lady presented at the Sarawak General Hospital, Kuching, Malaysia with a history of a progressive, painless left upper quadrant abdominal swelling for a year. CT scan showed a well-defined heterogeneously enhancing cystic mass measuring 7.5x7.5x8.1cm with a poor plane with the adjacent greater curvature of stomach and transverse colon. Upper and lower endoscopy was normal. The tumour was completely dissected from the adjacent transverse colon and removed laparoscopically. Histopathological examination of the resected specimen revealed a myxoid liposarcoma. She had an uneventful recovery and was discharged well on the third postoperative day. She subsequently underwent adjuvant chemotherapy and was well at 1-year follow-up with PET CT showing no evidence of recurrence or metastases.