Investigating Thermal Parameters of PVDF Sensor in the Front Pyroelectric Configuration

A metalized PVDF pyroelectric (PE) sensor was used as an optically opaque sensor and in a thermally thick regime for both sensor and sample, instead of a very thick sensor in the conventional front PE configuration. From the frequency dependence measurements, the normalized amplitude and phase signal were independently analyzed to obtain the thermal effusivity of the sensor. The differential normalized amplitude measured with water as a substrate was analyzed to determine the sensor thermal diffusivity. The PVDF thermal diffusivity and thermal effusivity agree with literature values. Then, from the known thermal parameters of the sensor, the thermal effusivity of a standard liquid sample, glycerol, and other liquids were obtained by the similar procedure.     

Single-mode D-shaped optical fiber sensor for the refractive index monitoring of liquid

A new fabrication method is introduced for the production of D-shaped optical fiber. A mechanical end and edge polishing system with aluminum oxide polishing film is utilized to perform sequential polishing on one side (lengthwise) of single-mode optical fiber in order to obtain a D-shaped cross section. Adjusting specific mechanical parameters allows for control of the volume of the D-shaped zone, while the fiber surface smoothness is governed by selection of polishing film grit size. To meet the accuracy and repeatability requirements, optical power loss is monitored during the entire polishing process in situ and in real time. This proposed technique possesses advantages of rapidity, safety, simplicity, repeatability and stability with high precision in comparison with contemporary methods for production. Sensor performance tests on the fiber reveal a linear response with linearity up to R² = 0.984 for surrounding refractive index in the range of 1.320–1.342 refractive index, which corresponds to different concentrations of the glucose solution test environment. The produced D-shaped optical fiber has potential sensing and monitoring applications in chemical, environmental, biological and biochemical fields.     

Design and fabrication of coaxial surface junction thermocouples for transient heat transfer measurements

Low cost coaxial surface junction thermocouples (CSJTs') have been fabricated in-house and calibrated to measure the transient surface temperature rise within a UNITEN's shock tube wall facility, consisting of K-type coaxial thermocouple elements. The aim of this paper is to explain the design technique of the CSJTs' and the difficulties that have occurred during the fabrication process. The microstructural analysis and the chemical characterization for these types of thermocouples have also been carried out to verify the surface morphology and to qualitatively evaluate the CSJT materials composition. The preliminary testing was performed to demonstrate the performance of these thermocouples to be used for measuring the surface temperatures and heat transfer rates under transient conditions. The preliminary results from shock tube tests have shown that these thermocouples have a time response on the order of microseconds and were suitable for making heat transfer measurements in highly transient conditions. It was concluded that the current construction technique produced gauges that were reliable, reproducible, rugged and inexpensive.     

A dynamic modeling to measure lean performance within lean attributes

In today’s competitive world lean manufacturing has become an important “role model” for two groups: academics and practitioners. Many organizations around the world have attempted to implement it but the lack of a clear understanding of the main attributes to leanness, lean performance and its measurement contribute to the failure of lean practices. It therefore seems necessary to provide a way to evaluate the impact of lean attributes using an approach to determine the criteria and key factors of leanness. Although there are numerous theoretical and practical studies that address lean tools and techniques, few studies focus systematically on measuring the influence of lean attributes on leanness. To fill the current gap, this paper presents an innovative approach to measure the value of the influence of lean attributes on manufacturing systems by using fuzzy membership functions. A lean attributes score is finally calculated to give managers and decision makers a real insight into the leanness level and to further improve it by acting appropriately in the manufacturing system. The model is dynamic, flexible, feasible, and easy to follow and implement. It enables a systematic measurement of the influence of lean attributes by producing a final integrated unit score.     

Optimization of Serine Protease Purification from Mango (Mangifera indica cv. Chokanan) Peel in Polyethylene Glycol/Dextran Aqueous Two Phase System

Mango peel is a good source of protease but remains an industrial waste. This study focuses on the optimization of polyethylene glycol (PEG)/dextran-based aqueous two-phase system (ATPS) to purify serine protease from mango peel. The activity of serine protease in different phase systems was studied and then the possible relationship between the purification variables, namely polyethylene glycol molecular weight (PEG, 4000-12,000 g·mol(-1)), tie line length (-3.42-35.27%), NaCl (-2.5-11.5%) and pH (4.5-10.5) on the enzymatic properties of purified enzyme was investigated. The most significant effect of PEG was on the efficiency of serine protease purification. Also, there was a significant increase in the partition coefficient with the addition of 4.5% of NaCl to the system. This could be due to the high hydrophobicity of serine protease compared to protein contaminates. The optimum conditions to achieve high partition coefficient (84.2) purification factor (14.37) and yield (97.3%) of serine protease were obtained in the presence of 8000 g·mol(-1) of PEG, 17.2% of tie line length and 4.5% of NaCl at pH 7.5. The enzymatic properties of purified serine protease using PEG/dextran ATPS showed that the enzyme could be purified at a high purification factor and yield with easy scale-up and fast processing.