Mahbubul Haque

Chemical bonding states and solar selective characteristics of unbalanced magnetron sputtered TixM1−x−yNy films

Transition metal nitride TixM1−x−yNy (M = Al or AlSi) based thin films are evaluated as solar selective surfaces by correlating their spectral selective features with their crystal structure and chemical bonding state including mechanical strength. Ti0.5N0.5, Ti0.25Al0.25N0.5, and Ti0.25Al0.2Si0.05N0.5 films were synthesized on AISI M2 steel substrates via closed field unbalanced magnetron sputtering technology. These were investigated using XRD, SEM, XPS, UV-Vis, FTIR and nanoindentation techniques. Analysis of the optical properties showed the solar absorptance, in the visible range, of the TixM1−x−yNy films improved significantly from 51% to 81% with AlSi-doping and an increase of solar absorptance of up to 66% was recorded from films doped with Al. Moreover, the Al doping can reduce the thermal emittance in the infrared range from 6.06% to 5.11%, whereas doping with AlSi reduces the emittance to ca. 3.58%. The highest solar selectivity of 22.63 was achieved with TiAlSiN films. Mechanical studies showed enhanced hardness by ∼32%; enhanced yield strength by ∼16% and enhanced plastic deformation by ∼110% of Al and AlSi doped TiN matrix.

Applying Value Stream Mapping for Productivity Improvement of a Metal Stamping Industry

To sustain in business by meeting the customer expectations with limited resources under tight schedule is a great challenge for high volume manufacturing industry. In this respect Value Stream Mapping (VSM) plays an important role as a strategic tool in streamlining the processing operations and enhances capacity utilization. This study has been conducted on application of VSM in a make-to-order metal stamping company engaged in production of different stamped parts of which the LCD TV frame is a significant one. Based on the product flow analysis, a current state VSM has been constructed using pertinent data collected from the production floor. Analysis of recorded videos and time studies were performed in order to figure out the scope of improvements in framing the future state map (FSM) in the context of cycle time reduction and line balancing efficiency. As observed from the FSM, the efficiency of production line is possible to be significantly increased from about 48% to more than 93% vis-à-vis a reduced batch completion cycle time. Thus it is obvious that with minor adjustments in the system in line with the findings of the study, the industry can make a substantial improvement in their operational efficiency.

Securing Superior Properties of Composite (PP+WF) through Central Composite Design

Due to numerous attractive properties, use of composites is in increasing trend. Efforts are being made to develop new composites securing their useful properties at optimum level for more demanding applications. The purpose of this project is to optimize the mechanical properties of composite (polypropylene + wood fiber) using Central Composite Design (CCD) technique. Accordingly experiments were conducted to develop mathematical models in terms of three process parameters - composition (percentage of PP and wood fiber), injection pressure (bar), and time (second) for functional characteristics such as tensile strength and water absorption. Design expert software was used for convenience to carry out the analysis with a view to identifying the optimum level of the processing parameters for securing the desirable properties of the composite.