Loss Quantization of Reflectarray Antenna Based on Organic Substrate Materials

This paper presents novel loss quantization of reflectarray elements based on organic substrate materials. Three differently composed substrate materials derived from recycled materials have been characterized for their dielectric properties using a broadband analysis technique. The materials show low dielectric permittivity values of 1.81, 1.62 and 1.84 for X-band frequency range. In order to estimate the reflection loss of for the three substrates a mathematical relation has been established using empirical data generated by computer simulated models. The reliability of the proposed model has been established by simulation and fabrication of unit reflectarray rectangular patch elements on three proposed substrate substrates. A broadband frequency response has been depicted by scattering parameter analysis of unit elements with 10% fractional bandwidth of 312, 340 and 207 MHz for RCP50, RCR75 and RNP50 substrate respectively

Loss quantization of reflectarray antenna based on organic substrate materials

This paper presents novel loss quantization of reflectarray elements based on organic substrate materials. Three differently composed substrate materials derived from recycled materials have been characterized for their dielectric properties using a broadband analysis technique. The materials show low dielectric permittivity values of 1.81, 1.62 and 1.84 for X-band frequency range. In order to estimate the reflection loss of for the three substrates a mathematical relation has been established using empirical data generated by computer simulated models. The reliability of the proposed model has been established by simulation and fabrication of unit reflectarray rectangular patch elements on three proposed substrate substrates. A broadband frequency response has been depicted by scattering parameter analysis of unit elements with 10% fractional bandwidth of 312, 340 and 207 MHz for RCP50, RCR75 and RNP50 substrate respectivel

A wideband reflectarray antenna based on organic substrate materials

Significant improvements in terms of bandwidth of reflectarray antennas have been achieved by introduction of innovative paper substrate dielectric materials. Three differently custom composed organic dielectric substrates have been characterized for dielectric properties using a broadband technique based on open ended coax cable method. The substrates show low dielectric permittivities of 1.81, 1.63 and 1.84 along with a loss tangent of 0.053, 0.047 and 0.057. Validation of using the proposed substrates for reflectarray antenna was done by modelling and fabricating reflectarray unit elements on the three substrates. Scattering parameter analysis of unit reflectarray elements show encouraging results with a broadband frequency response of 340 MHz at a phase gradient of 0.14 º/MHz. Thus the proposed substrate could serve exceptionally to address the narrow bandwidth problem in reflectarray antennas

Multiple responses optimisation in injection moulding parameter for polypropylene-nanoclay-gigantochloa scortechinii via Taguchi method

This paper presents the findings of multiple responses optimisation of overall quality performances for the samples made from the blend of polypropylene-nanoclay with different weight percentage of Gigantochloa Scortechinii fibres. The contents of fiber were set at 0 wt. %, 3 wt. % and 6 wt. %. The selected injection moulding parameters were packing pressure, melt temperature, screw speed and filling time. The overall quality performances that need to be improved upon the optimisation were flexural strength, warpage and shrinkage. This research started by drying the fibres at 120°C before mixing the fibres with polypropylene, compatibilizer (polypropylene grafted maleic anhydride) and nanoclay. The compounding of these nanocomposites was performed before injection moulding by using lab compounder and palletizer. The multiple responses optimisation process was compiled by adding the signal to noise ratio for each responses. As for the results, for control sample (0 wt. % fibre) the validated S/NQP was 112.173 dBi by using the optimised parameter. These values were used for comparison purposed. As for the 3 wt. % of fibre content, the validated S/NQP was 133.313 dBi at 35% of packing pressure with 170°C setting of melt temperature. The filled time was 3 seconds with 35% of screw speed. As for the 6 wt. % setting, the validated S/NQP was 135.835 dBi with the same setting of packing pressure and screw speed but with different setting of melt temperature (175°C) and filled time (2 seconds). The most influential parameter for control sample was melt temperature but the parameter changed to packing pressure when the fibre was added. Therefore existence of fibre was proven to affect towards the end results. Inconclusion, the optimum values of parameter setting and fibre contend will improve the quality performances specifically for products samples made from polypropylene-nano clay Gigantochloa Scortechinii. This material obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products

Multiple responses optimisation in injection moulding parameter for polypropylene-nanoclay-gigantochloa scortechinii via taguchi method

This paper presents the findings of multiple responses optimisation of overall quality performances for the samples made from the blend of polypropylene-nanoclay with different weight percentage of Gigantochloa Scortechinii fibres. The contents of fiber were set at 0 wt. %, 3 wt. % and 6 wt. %. The selected injection moulding parameters were packing pressure, melt temperature, screw speed and filling time. The overall quality performances that need to be improved upon the optimisation were flexural strength, warpage and shrinkage. This research started by drying the fibres at 120°C before mixing the fibres with polypropylene, compatibilizer (polypropylene grafted maleic anhydride) and nanoclay. The compounding of these nanocomposites was performed before injection moulding by using lab compounder and palletizer. The multiple responses optimisation process was compiled by adding the signal to noise ratio for each responses. As for the results, for control sample (0 wt. % fibre) the validated S/NQP was 112.173 dBi by using the optimised parameter. These values were used for comparison purposed. As for the 3 wt. % of fibre content, the validated S/NQP was 133.313 dBi at 35% of packing pressure with 170°C setting of melt temperature. The filled time was 3 seconds with 35% of screw speed. As for the 6 wt. % setting, the validated S/NQP was 135.835 dBi with the same setting of packing pressure and screw speed but with different setting of melt temperature (175°C) and filled time (2 seconds). The most influential parameter for control sample was melt temperature but the parameter changed to packing pressure when the fibre was added. Therefore existence of fibre was proven to affect towards the end results. In conclusion, the optimum values of parameter setting and fibre contend will improve the quality performances specifically for products samples made from polypropylene-nanoclay- Gigantochloa Scortechinii. This material obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products

Susceptibility of stingless bee, giant bee and asian bee honeys incorporated cellulose hydrogels in treating wound infection

Wound healing and wound management are among challenging clinical problems, despite the advancement in medical technology and research. Honey is one of the natural products, synthesized by honey bees that exhibits great antibacterial and medicinal properties. Incorporation of honey into modern dressing materials such as cellulose hydrogel is beneficial to anticipate cell proliferation while preventing infection in a wound region. This study reports the fabrication of honey cellulose hydrogels for reliable alternative treatment of wound infection. The cellulose hydrogels were incorporated with three types of mainland Southeast Asia honeys of stingless bee, giant bee and Asian bee, independently. Each hydrogel was subjected to ATR-FTIR analysis for the determination of chemical composition. The antibacterial properties of honey hydrogels were evaluated through zone inhibition and colony count tests against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The cytocompatibility of the honey hydrogels was then evaluated through MTT assay and cell scratch assay with human skin fibroblast cells. The composition of honey and cellulose hydrogel were verified with the appearances of fingerprint bandwidth and identical peaks of both compounds. The giant bee honey hydrogels produced the highest bacterial retardation through both antibacterial tests. The stingless bee honey hydrogels projected susceptibility towards E. coli while the Asian bee honey hydrogels projected susceptibility towards S. aureus. Among these three variations of honey hydrogels, the in-vitro cytocompatibility analyses testified the greatest cell viability and cell migration on the stingless bee honey hydrogels compared to the Asian bee honey hydrogels, giant bee honey hydrogels and control hydrogels. The findings support the potential of honey hydrogels as a reliable alternative treatment for wound infection

Evaluation of sound comfort in examination hall using acoustical environmental analyses

Acoustics environmental analyses were conducted in the unoccupied examination hall at Universiti Tun Hussein Onn Malaysia (UTHM), in order to determine the acoustical environment which reflects to sound comfort during sitting exam. The acoustic parameters that measured are background noise level, sound pressure level and reverberation time. The analysis result of untreated wall condition (without absorbent material) was revealed poor while treated wall condition (with absorbent material) revealed the improvement result. Installation of absorbent material on the wall and speakers rearrangement had reduced the highest background noise level of examination hall average reverberation times. A minor alteration at examination hall had contributed to better acoustic performance

Evaluation of sound comfort in examination hall using acoustical environmental analyses

Acoustics environmental analyses were conducted in the unoccupied examination hall at Universiti Tun Hussein Onn Malaysia (UTHM), in order to determine the acoustical environment which reflects to sound comfort during sitting exam. The acoustic parameters that measured are background noise level, sound pressure level and reverberation time. The analysis result of untreated wall condition (without absorbent material) was revealed poor while treated wall condition (with absorbent material) revealed the improvement result. Installation of absorbent material on the wall and speakers rearrangement had reduced the highest background noise level of examination hall average reverberation times. A minor alteration at examination hall had contributed to better acoustic performance

Multiple responses optimisation in injection moulding parameter for polypropylene-nanoclay-gigantochloa Scortechinii via Taguchi method

This paper presents the findings of multiple responses optimisation of overall quality performances for the samples made from the blend of polypropylene-nanoclay with different weight percentage of Gigantochloa Scortechinii fibres. The contents of fiber were set at 0 wt. %, 3 wt. % and 6 wt. %. The selected injection moulding parameters were packing pressure, melt temperature, screw speed and filling time. The overall quality performances that need to be improved upon the optimisation were flexural strength, warpage and shrinkage. This research started by drying the fibres at 120°C before mixing the fibres with polypropylene, compatibilizer (polypropylene grafted maleic anhydride) and nanoclay. The compounding of these nanocomposites was performed before injection moulding by using lab compounder and palletizer. The multiple responses optimisation process was compiled by adding the signal to noise ratio for each responses. As for the results, for control sample (0 wt. % fibre) the validated S/NQP was 112.173 dBi by using the optimised parameter. These values were used for comparison purposed. As for the 3 wt. % of fibre content, the validated S/NQP was 133.313 dBi at 35% of packing pressure with 170°C setting of melt temperature. The filled time was 3 seconds with 35% of screw speed. As for the 6 wt. % setting, the validated S/NQP was 135.835 dBi with the same setting of packing pressure and screw speed but with different setting of melt temperature (175°C) and filled time (2 seconds). The most influential parameter for control sample was melt temperature but the parameter changed to packing pressure when the fibre was added. Therefore existence of fibre was proven to affect towards the end results. In conclusion, the optimum values of parameter setting and fibre contend will improve the quality performances specifically for products samples made from polypropylene-nanoclayGigantochloa Scortechinii. This material obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products