Measurement of Line Distribution of Thermal Contact Resistance Using Microscopic Lock-In Thermography

This paper proposes a new thermal contact resistance measurement method using lock-in thermography. Using the lock-in thermography with an infrared microscope, the local temperature behavior in the frequency domain across the contact interface was visualized in microscale. Additionally, a new thermal contact resistance measurement principle was constructed considering the superimposition of the reflected and transmitted temperature wave at the boundary and taking into account the intensity distribution of the heating laser as the gaussian distribution, and the specific geometrical condition of the laminated plate sample. As a result of the experiments, the one-dimensional distribution of the thermal contact resistance was obtained along the contact interface from the analysis of the phase lag.

Lapisan Plasma Spray Ni-Al dan Al-Si Pada Tabung Baja Tahan Karat Austenitik Dengan Jarak Semprot Terbatas (Atmospheric Plasma Spray Coating of Ni-Al and Al-Si on Austenitic Stainless-Steel Tube with Limited Short Spray Distance)

Atmospheric Plasma Spray (APS) coating is a widely used thermal spray coating process in industrial applications. High density and high bond strength coating are the main features of this process that is required in almost coating properties for specific applications. The geometrical condition of the workpiece substrate dictates the parameter needed to achieve a certain quality of the coating. Changes in the geometry require modification on the parameter of the process to maintain the quality of the coating. Aluminum Silicon and Nickel Aluminum coating were applied on Stainless Steel substrate casing. Due to the limitation of spray distance between nozzle gun and substrate surface of the casing, modified several parameters of the process were taken. Several parameters were investigated to find out the optimum result of coating and verified with tensile bond strength test, hardness test, and microscopic analysis examination. These activities that involved modification of parameters, mechanical testing, and visual inspection informed that power as a function of voltage and ampere, powder feed rate, the surface speed of substrate (the particular amount of workpiece rotation per minute), and traverse speed of gun, contribute to the result of the optimum coating.

Group consensus coordination control in networked nonholonomic multirobot systems

In this article, the coordination control problem of group tracking consensus is considered for networked nonholonomic mobile multirobot systems (NNMMRSs). This problem framework generalizes the findings of complete consensus in NNMMRSs and group consensus in networked Lagrangian systems (NLSs), enjoying capacious application backgrounds. By leveraging a kinematic controller embedded in the adaptive torque control protocols, a new convergence criterion of group consensus is established. In contrast to the formulation under strict algebraic assumptions, it is found that group tracking consensus for NNMMRSs can be realized under a simple geometrical condition. The system stability analysis is dictated by the property of network topology with acyclic partition. Finally, the theoretical achievements are verified by illustrative numerical examples. The results show an interesting phenomenon that, for NNMMRSs, the state responses exhibit negative correlation with the algebraic connectivity and coupling strength.

A Hybrid Multi-Criteria Decision Making Model for Defect-Based Condition Assessment of Railway Infrastructure

The condition of railway infrastructure, such as rails, ballasts and sleepers, should always be monitored and analyzed to ensure ride safety and quality for both passengers and freight. It is hard to assess the condition of railway infrastructure due to the existence of various components. The existing condition assessment models are mostly limited to only assess track geometry conditions and structural condition of the railway infrastructure. Therefore, the present research develops a defect-based structural and geometrical condition model of railway infrastructure. The defects of each component are identified and examined through literature and experts in the field. Two main inputs are used to develop the model: (1) the relative weight of importance for components, defects and their categories and (2) defects severities. To obtain the relative weights, the analytic network process (ANP) technique is adopted. Fuzzy logic is used to unify all the different defect criteria and to interpret the linguistic condition assessment grading scale to a numerical score. Hence, the technique for order preference by similarity to ideal Solution (TOPSIS) is used to integrate both weights and severities to determine the railway infrastructure condition. The developed model gives a detailed condition of the railway infrastructure by representing a three-level condition state, for defect categories, components and an overall railway infrastructure. The developed model is implemented to five case studies from Ontario, Canada. The developed model is validated by comparing its results with the real case studies results, which shows similar results, indicating the robustness of the developed model. This model helps in minimizing the inaccuracy of railway condition assessment through the application of severity, uncertainty mitigation and robust aggregation

Asymptotic synchronization of a coupled system of wave equations on a rectangular domain with reflecting sides

We show the sufficiency of Kalman’s rank condition for the uniqueness of solution to a coupled system of wave equations in a rectangular domain. The approach does not need any gap condition on the spectrum of the differential operator and the usual multiplier geometrical condition. Then, the study on the asymptotic synchronization by groups can be improved for the corresponding system.

Design of Tendon-Driven Mechanism Using Geometrical Condition

A tendon-driven robot offers many advantages, such as easy designs for mass distribution that facilitate dexterous motion. A procedure to design such a robot using a single actuator to achieve the desired force direction and magnitude on an endpoint is presented herein. The force on the endpoint is generated by the single actuator and a wire that passes through pulleys attached on links. To set the pulley position for the desired force direction and magnitude, a geometrical condition is proposed. To evaluate the proposed method, a physical monopod robot was developed. We compared the calculated and physical forces on the endpoint of the physical robot for the desired directions. Finally, we confirmed that the proposed method provided the desired force on the endpoint without iterative trials.

A Reviews on Behaviour of Industrial Chimneys

Review article contains various research paper related to the topic chimney and forces acting on it like the seismic force, earthquake forces as well as geographical condition, fundamental time, model analysis and software analysis and modelling of the chimney. Various software is used to analysis and modelling of the chimney.in this paper discuss various modelling concept and problem behind them. The purposes of this paper are to identify the problem associate with a chimney as per Indian geometrical condition as well as the seismic zone in India. This review paper help to improve knowledge regarding design and modelling methodology aspects.