Corrosion at the bottom of a ship’s water line can result in personnel and material safety risks. There are 2 (two) ways to protect against corrosion, they are passive protection (by painting) and active protection (by cathodic protection method). In the KRI with KCR-40 type, the design of the bottom line of the ship’s waterline protection has been carried out with ICCP, but the value of its failure risk and reliability is unknown, both functional and designs, so that the design of the tool cannot be used maximally. This research aimed to determine the factors of failure and reliability value of the design-based ICCP (Reliability by Design) with the FTA and FMEA approach, the FTA aimed to identify the risks that contribute to the failure. The main factors causing failure in the design of ICCP tools occur in the component of Steel potential indicator and rectifier indicator with a failure mode not pointing to the correct number, this will result in corrosion control which is expected to be uncontrolled properly and correctly due to incorrect data input. After analyzing the FTA, the reliability value was 33%. Mitigation of tool components that have a high level of risk among other things in the indicator of steel potential and rectifier indicators: the first was to redesign the laying of some components of the tool compilers to pay attention to the circulating circulation in the box so that the tool works more optimally, the second was to carry out periodic control while the device was operating, and third was to ensure that the electrical power used was stable so there were no problems with the ICCP device while the ICCP device was operating.
The penetration of fuel spray as a result of the mixture of fuel droplet and entrained air usually generate nonlinear models whose solutions are normally difficult to realize analytically. This present study presents general approximate analytical solution to such problem by employing Differential transform Method (DTM). At the level of two-phase flow, the spray droplets and the entrained air have the same flow velocity. In order to fully understand the process, the parameters present in the governing equations are carefully studied. The obtained solution employing DTM is verified with Numerical Runge-Kutta (RKF45) and also compared with similar past works. Furthermore, the acquired results for different ambient densities and injection velocities are depicted and discussed. The results illustrate that continuous increase in the initial velocity and orifice diameter cause a corresponding increase in spray penetration while an antonymous effect is noticed for an increased semi cone angle and density. This work will find vital applications in the optimization of systems whose operation are influence by the aforementioned spray penetration processes.
In the present paper, we focus on the melting heat transfer characteristics of Casson fluid involving thermal radiation and viscous dissipation. To this end, the governing partial differential equations (PDEs) are transformed into the ordinary differential equations (ODEs) via the similarity variables. Besides establishing a homotopy-based methodology and its optimization performed in MATHEMATICA package BVPh2.0, the present findings are compared and validated by those available results in the literature. It can be shown that regardless of the variable fluid properties, this methodology predicts the heat transfer rate with and without melting effect at any Prandtl number. Furthermore, it is seen that the velocity distribution is significantly affected by the melting parameter.
Dynamic analysis of isotropic thin rectangular plate resting on two-parameter elastic foundations is investigated. The governing system is converted to system of nonlinear ordinary differential equation using Galerkin method of separation. The Ordinary differential equation is analyzed using hybrid method of Laplace transform and Variation of iteration Method. The accuracies of the analytical solutions obtained are verified with existing literature and confirmed in good agreement. Thereafter, the analytical solutions are used for parametric studies. From the results, it is observed that, increase in elastic foundation parameters increases the natural frequency. Increase in aspect ratios increases the natural frequency. It is expected that the present study will add value to the existing knowledge in the field of vibration.
Software plays an important role in the ISRO space mission. Reliability of this software is vital to achieve zero defects in space systems and services. There are varieties of software used in realization of spacecraft. Mainly it is categorized into onboard, mission and ground software. Evaluation of this software is the major activity for a software quality assurance person. Software quality engineer has to certify the software based on system level requirements, mission requirements and functional requirements. All the hardware and software interactions also have to be verified. Risk management is the key factor for effective software management. Software life cycle activities are carried out based on ISRO software process document. Following these standards and guidelines helps to find the defects in the earlier phase of software development life cycle. This paper mainly describes the software quality assurance activities carried out for control drive electronics unit used in GSAT spacecraft. SQA activities complied against the IEEE12207 standards (ISPD-2) at ISRO level. Pulse Tube Cryocoolers are active cryogenic devices used to generate cryogenic temperatures in the 50K-80K range in a single stage. Cryocooler drive electronics unit generates identical drive to both the compressors of pulse tube cryocooler.
