61www.ijeas.org  Abstract-Conventional black tea is produced using variety of tea leaves called Camellia sinensis (species of evergreen shrub or small tree whose leaves and leaf buds are used to produce black tea). Black tea processing production involve plucking, withering, maceration/rolling, cutting, oxidation/fermentation and drying. In the conventional black tea process, CTC (Cutting, Tearing and Curling) is where tea leaves are cut to rapture plant cells so as to release catechins for oxidation / fermentation for 2 hours before being stopped in the dryer at a temperature of 130O C. The CTC tea manufacturing process produces high quality teas. High pressure Rotorvane has been designed for processing of Orthodox teas [1] by converting standard Rotorvane from Low to high Pressure [2] and tested to produce Orthodox Large Particle Tea that is able to infuse like normal conventional black CTC teas [3]. To check impact of high pressure Rotorvane on CTC black tea, factory trials were done using 15'' Rotorvane at different pressures and were then tracked through the innovation manufacturing process. Made tea samples for each trial were drawn and assessed by tea tasters for quality using the Unilever International Tea Categorisation System (ITCS) and quality comparisons made. It was found out that the higher the Rotorvane pressure the higher the quality of CTC made tea to an optimum level of 25MN/m2 on quality parameters of Taste, Colour and Mouthfeel giving a taste score of 5.4 which is 0.4 above conventional CTC made tea quality of 5.0. Leaf appearance score remained the same at 5. From the conclusion obtained, high pressure Rotorvane should be used as a standard equipment in the processing of high-quality CTC teas in the Tea industry.

The shape of the modal duct of an acoustic wave propagating in a muffling system varies with the internal geometry. This shape can be either as a result of plane wave propagation or three-dimensional wave propagation. These shapes depict the distribution of acoustic pressure that may be used in the design or modification of mufflers to create resonance at cut-off frequencies and hence achieve noise attenuation or special effects on the output of the noise. This research compares the shapes of acoustic duct modes of two sets of four pitch configurations of a helicoid in a simple expansion chamber with and without a central tube. Models are generated using Autodesk Inventor modeling software and imported into ANSYS 18.2, where a fluid volume from the complex computer-aided-design (CAD) geometry is extracted for three-dimensional (3D) analysis. Mesh is generated to capture the details of the fluid cavity for frequency range between 0 and 2000Hz. After defining acoustic properties, acoustic boundary conditions and loads were defined at inlet and outlet ports before computation. Postprocessed acoustic results of the modal shapes and transmission loss (TL) characteristics of the two configurations were obtained and compared for geometries of the same helical pitch. It was established that whereas plane wave propagation in a simple expansion chamber (SEC) resulted in a clearly defined acoustic pressure pattern across the propagation path, the distribution in the configurations with and without the central tube depicted three-dimensional acoustic wave propagation characteristics, with patterns scattering or consolidating to regions of either very low or very high acoustic pressure differentials. A difference of about 80 decibels between the highest and lowest acoustic pressure levels was observed for the modal duct of the geometry with four turns and with a central tube. On the other hand, the shape of the TL curve shifts from a sinusoidal-shaped profile with well-defined peaks and valleys in definite multiples of π for the simple expansion chamber, while that of the other two configurations depended on the variation in wavelength that affects the location of occurrence of cut-on or cut-off frequency. The geometry with four turns and a central tube had a maximum value of TL of about 90 decibels at approximately 1900Hz.

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