Comparison between two anammox fiber fillers under load impact and the effect of HCO3− concentration

Based on the establishment of a stable anaerobic ammonia oxidation treatment system in 100 days, the impact resistances of two different anammox fiber fillers (the curtain filler: R1 and the bundle filler: BR) were compared.

On the tribology of complex 2D/3D composites bearing

In the present work, a hierarchical braided polymer composite consists of Polytetrafluoroethylene (PTFE) fibers, reinforcement fibers, and epoxy resin was designed as a self-lubricant composite and bearing. Different reinforcements such as glass, carbon, and Kevlar fibers were employed to investigate the effect of reinforcement on the wear characteristics of composites. Besides, the influence of 2D/3D braid fabric was examined on the wear behavior of samples. Also, 90 and 120 N loads were applied to assess the load impact. Results illustrated that compared to glass and Kevlar, carbon could lead to a greater wear weight loss and friction coefficient. However, PTFE tribofilm was observed according to scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) analysis. Moreover, with the increase of load, the wear stability of the composites faded significantly. Furthermore, the tribological features became inappropriate with the deployment of the 3D braid structure. Finally, the modeling of tribological parameters was carried out using response surface methodology-based D-optimal design. The adequacy of the models was checked by analysis of variance. Results implied that there is an excellent correlation between the model and the experiments.

Analysis and Research on the Cause of Wind Turbine Blade Bolt Fracture

In 2019, inspection personnel of a wind farm went to the tower and found that a total of 6 bolts of blades in the hub of a wind turbine had broken and failed. In order to find out the cause of fracture, the fracture bolt was comprehensively detected and analyzed by means of appearance morphology analysis, chemical composition analysis, mechanical properties testing, microstructure testing and fracture micro-area analysis. The results show that the main reasons for the bolt fracture are as follows: under the action of the bolt’s constantly changing and repeated wind load impact and the alternating load caused by blade rotation during the operation of the fan, the crack source is formed along the bottom of the thread with serious stress concentration and expands in fatigue mode until the whole fracture fails.

Mechanical and Tribological Behaviour of Hybrid Multi Fibre Reinforced Nylon 6-6 Nanocomposites

The investigation on the effect of adding silane modified chopped E-glass fibre and Aluminium metal wire-mesh into nano silica toughened nylon 6-6 thermoplastic composites on mechanical, drop load impact, fatigue and tribological behaviour is studied in this paper. The primary aim of this research work is to develop a hybrid Nylon 6-6 nanocomposites having high stiffness, toughness and wear resistance. The chopped glass fibre and Al wire-mesh was surface treated with the help of 3-Aminopropyletrimethoxylane (silane) and acid etching. The tensile results revealed that additions of glass fibre and Al mesh into nano - silica toughened nylon 6-6 composite gives improved tensile and flexural strength. Similarly, the Izod impact strength of Al-mesh reinforced nano silica (1vol.%) toughened nylon 6-6 gives superior energy absorption up to 6 Joules/cm. The drop load impact penetration of composite N3 (59% - Nylon 66, 20% - E-glass fibre, 20% - Al wire mesh and 1 % - nano silica) shows very limited penetration than other composites. Highest fatigue life of 16391 cycles was observed for the composite designated N3, which contains 1 vol.% of nano silica, whereas the composite containing 2 vol.% of nano silica gives very lower specific wear rate and Co-efficient of friction. The developed composite which has better modulus, stiffness, wear resistance and fatigue life could be possibly used in automobile power transmission gears, domestic equipment and farm related machineries.

Application of Analytical Hierarchy Process for Structural Health Monitoring and Prioritizing Concrete Bridges in Iran

This paper proposes a method for monitoring the structural health of concrete bridges in Iran. In this method, the bridge condition index (BCI) of bridges is determined by the analytical hierarchy process (AHP). BCI constitutes eight indices that are scored based on the experts’ views, including structural, hydrology and climate, safety, load impact, geotechnical and seismicity, strategic importance, facilities, and traffic and pavement. Experts’ views were analyzed by Expert Choice software, and the relative importance (weight) of all eight indices were determined using AHP. Moreover, the scores of indices for various conditions were extracted from experts’ standpoints. BCI defines as the sum of weighted scores of indices. Bridge inspectors can examine the bridge, determine the scores of indices, and compute BCI. Higher values of BCI indicate better conditions. Therefore, bridges with lower BCI take priority in maintenance activities. As the case studies, the authors selected five bridges in Iran. Successful implementation of the proposed method for these case studies verified that this method can be applied as an easy-to-use optimization tool in health monitoring and prioritizing programs.

Performance Analysis of CloudLinux-based Web Server at the Embassy of the Kingdom of Morocco in Jakarta

The rapid development of Information Technology (IT) has made a high availability web server a necessity. CloudLinux is a CentOS-based operating system specifically for the needs of servers with good high availability. This study will implement and analyze a CloudLinux-based web server for the Embassy of the Kingdom of Morocco in Jakarta to replace the current CentOS-based web server that does not meet high availability standards. The research methodology used in this study is the PPDIOO Life-cycle from Cisco. Designing a network according to the customer's needs requires identifying several elements in it, including the goals and constraints faced by the organization. Cisco creates a network life-cycle that can help these problems into six phases: Prepare, Plan, Design, Implement, Operate, and Optimize (PPDIOO). This study aims to determine how well the uptime, response time, and load impact are on the CloudLinux-based web server. The uptime test results on the CloudLinux-based web server have a value of an average of 99.971%. Testing the response time on the CloudLinux-based web server has an average value of 684.75ms (milliseconds). The results of the load impact test on the CloudLinux-based web server using ten virtual users (10VU) has a total value of 7595 requests, load impact using fifteen virtual users (15VU) has a total value of 11315 requests, and finally, load impact using twenty-five virtual users (25VU) has a total value of 18631 requests.