Tension control Bolts (TC Bolts) are specialized fasteners mainly utilized in steel frame construction. They include a pre-assembled bolt, nut, and washer for simplified installation. In contrast to standard Bolts, TC Bolts have a domed head and a distinctive spline design that enables accurate tensioning during the installation process. This advancement has led to their growing popularity in the construction sector because of their effectiveness and dependability. In this article, examined this type of Bolts, installation mechanism, their advantages over conventional high-strength structural Bolts, challenges and considerations, durability comparison between traditional and TC Bolts, design features, installation process, and also review the relevant standards associated with them.

Introduction: The aim of this study was to develop an optimized formulation for labeling a third-generation bisphosphonate, zoledronic acid with [99mTc] Tc to achieve the best formulation in preparing an ideal skeletal radiotracer. Radiocomplex yield and purity, stability, biodistribution and imaging in normal rat were investigated. Methods: The samples containing different amounts of zoledronic acid, ascorbic acid and stannous chloride were prepared and labeled with [ 99m Tc]technetium pertechnetate. TLC methods were used to determine the radiochemical purity. The stability was determined in saline and human serum solutions. Lipophilicity was calculated by measuring radio-complex that was divided between organic and aqueous phases. In vitro bone affinity was studied through hydroxyapatite binding assays. Considering the decomposition of radioactivity, biodistribution of radio-complex was assessed based on the percentage of injected activity per gram of organ (% IA/g). Results: [99mTc]Tc-zoledronic acid was prepared easily with high yield while 100 µ, g, 0. 34 µ, mol of zoledronic acid as a ligand and 100 µ, g, 0. 44 µ, mol SnCl2 as a reducing agent were used. Radiochemical purity of radio-complex was more than 99% with specific activity of 8050 MBq/µ, mol. The radio-complex showed rapid blood washout along with high bone uptake value (4. 53 ±,0. 14 % IA/g at 2 h post injection). Conclusion: Under optimized condition, [99mTc]Tc-zoledronic acid was prepared with high purity and stability together with high bone affinity and rapid blood clearance, make this radio-complex an ideal agent with great potential for skeletal imaging.

Objectives: 99mTc-MAG3 is a standard radiotracer for renal dynamic functional study. Despite its properties for clinical uses, it has numerous technical limitations. 99mTc-EC is also a tubular radiotracer for renal imaging, which has not been used worldwide. In this study, the use of 99mTc-EC and 99mTc-MAG3 for renal functional study were compared.Methods: Thirty five patients (20 male, 15 female; mean age of 34.63 ±10.69 years) were entered in the study. About 10 mCi of 99mTc-EC and 99mTc-MAG3 were administered in different days within 7 days intervals and serial images were obtained for 30 minutes. Serum creatinine and visual scintigraphic findings of all patients were within normal limits.Results: In this study, the renal uptake of 99mTc-EC was significantly higher than 99mTc-MAG3 (6.20% vs 4.39% of the injected dose), while the hepatic activity of 99mTc-EC was significantly lower (307 vs 439 mean pixel count, p<0.0001). Also the absolute values for some other quantitative parameters such as right and left kidney transit times and ERPF were different for each radiotracer. In spite of these differences most quantitative parameters (except for right kidney transit time, liver uptake and Tmax of both kidneys) showed good correlations for both agents.Conclusion: The calculated ERPF with 99mTc-EC as compared to 99mTc-MAG3 is in closer proximity to the true values. Also the use of 99mTc-EC compared to 99mTc-MAG3 in clinic due to simplicity of preparation, higher stability, higher renal uptake, and lower hepatobiliary activity is better. Therefore the use of 99mTc-EC as an appropriate substitute or ever preferred radiopharmaceutical for 99mTc-MAG3 radiopharmaceutical for renal function studies is recommended.

Introduction: For renal scintigraphy, different radiopharmaceuticals like 99mTc-DMSA and 99mTc-EC can be used. Although these methods are accurate, some differences can be observed among them. These radiopharmaceuticals have different levels of reproducibility and repeatability. This study aimed to evaluate the level of inter and intra observer variability in 99mTc-DMSA scintigraphy. We also compared the renal function, measured with 99mTc-EC, with the one measured using 99mTc-DMSA scintigraphy to determine if 99mTc-EC can be used instead of 99mTc-DMSA in this regard.Methods: The sample volume consisted of 81 patients underwent both 99mTc-DMSA and 99mTc-EC in Imam Reza Health Center in 2008. These scans were interpreted by two observers. One of the observers interpreted the scans after one month for the second time. The data were analyzed with SPSS.Results: There was a close correlation between these two methods with respect to DRF (P = 0.51). Estimating intra observer variability showed close correlation between DMSA (r = 0.997) and EC (r = 0.996). The evaluation of inter observer variability also revealed high correlation between DMSA (r = 0.995) and EC (r = 0.996).Conclusion: Since the comparison between these two methods in measuring renal function showed the same results, 99mTc-EC can be used as a substitute for 99mTc-DMSA. In addition, Tc-99m EC scintigraphy can be a reliable single-modality study to evaluate renal cortical defects, perfusion, and drainage of the urinary system and indirect evidence of vesicoureteric reflux with the added advantage of low radiation exposure to the patient. Also good reproducibility and repeatability were reported according to this study.

In this study, the failure analysis of base plate Bolts of radial forging machine is investigated. Premature failure had occurred from the Bolts shank-head fillet and threads zones. Hardness, impact and tensile tests are carried out to investigate the mechanical properties and spectrophotometer is used to evaluate the Bolts chemical composition. Optical Microscope (OM) and Scanning Electron Microscope (SEM) are used for the investigation of microstructure, defects, fracture surface and failure causes. The fracture surface morphology shows that the crack growth consisted of Bolts shank-head fillet and threads zones including the initiation zone, fatigue crack growth zone along with the beach marks and ratchet steps and the rapid final fracture zone. Stress analysis shows that the amount of pre-tightening selected lower than the proposed value leads to the joint loosening and shortens the bolt’ s fatigue life. In addition, based on the paper results, the existing flowchart for component fabrication is analyzed and a flowchart based on research field is presented to enhance the quality of radial forging machine parts.

The robustness of steel joints in fire is important for steel building structures because of the need to prevent progressive collapse. Stainless steel is widely used in building construction mainly because of its corrosion resistance, but it also possesses improved fire resistance compared with conventional non-alloy, fine grain structural steels. Extensive research performed on the robustness of steel joints in fire has revealed that failure at elevated temperature may be controlled by bolt shear for fin plate and web cleat connections. Hence, this study focussed on the use of stainless steel in experimental tests conducted on fin plate and web cleat connections at high temperatures. In addition, this study investigated the use of a component-based model to predict connection performance at elevated temperature.