Merbok river catchment situated in the Kedah State receives its input from Bongkok River
and Puntar River flowing down and joining Lalang River to flow down to the Merbok
Estuary. The Merbok catchment (440 km2) is experiencing several degrees of complex
land uses activities that poses some impact on the suspended sediment production of
the Merbok river. A study was conducted to investigate the suspended sediment loading
of rivers draining the Merbok catchment from January to December 2013. Suspended
sediment budget of the Merbok catchment were estimated. The river suspended sediment
concentrations (SSC) and suspended sediment (SS) load increased during wet season
compared to dry season. The SS loads increases from upper catchment to river mouth. The
sediment loadings were divided into three segments- the upstream, middle segment and
lower segment. The SS loads increased from 10 t yr-1 in the upper part of Bongkok river
to 3336 t yr-1 in upper segment. The sediment loading then increase to 4299 t yr-1 in the
middle segment of the catchment (at Bongkok 4), and then exiting the Merbok Estuary, as
the lower segment, with a total amount of sediment output estimated at 7156 t yr-1. From this
total sediment output, most of the sediment
source came from the tributaries; the
Bongkok River at B3 (3337 t yr-1), Puntar
River (2924 t yr-1) and Lalang River (1370
t yr-1), which were much higher than its
proportion in terms of its length and drainage
area. As a conclusion, the inconsistence in
SSC in the river were influenced by the
various anthropogenic activities (especially
agriculture and urbanization activities) in the catchment area which necessitate future land use and sediment control to avoid sediment
and possible nutrient loading into the estuary.
Guava (Psidium guajava L.) is a rich source of vitamin C (ascorbic acid) having high water
content (above 80%) which makes it extremely perishable, but storage, handling, processing
and transporting becomes difficult due to high moisture content. Therefore, guava needs
dehydration process by upholding its natural colour and minimum ascorbic acid losses. We
have carried out a comprehensive study to examine the influence of different drying treatments;
under direct sunlight, freezing, convection oven (50, 60, 70, 80 and 90°C) and microwave
oven (100, 250, 440, 600 and 1000 watts) on ascorbic acid concentration and colour quality
of guava. The mean values of ascorbic acid concentration of dried guava slices were changed
significantly (P < 0.05) as compared to fresh guava slices. The colour of guava slices became
yellowish with an increase in temperature and power of conventional and microwave ovens,
respectively. We found freeze drying as the best method for the dehydration of guava in terms
of ascorbic acid and natural colour preservation.
A study has been conducted on pink guava juice (PGJ) fouling deposit. Several ex-situ experimental rigs were set-up to obtain PGJ fouling deposit, while the best ex-situ experimental rig was also selected. PGJ was heated at 93°C and its fouling deposit was obtained after 1 hour of heating. Then, it was used for the ex-situ cleaning study at 1 litre min-1, at several temperatures (70, 80 and 90°C), and in some chemical concentrations (1.6 v/v% of Maxiclean CP6 or 0.325 % OH-; 1.8 v/v% of Maxiclean CP6 or 0.369 % OH-; 2.0 v/v% of Maxiclean CP6 or 0.44 % OH-). The best cleaning combinations were investigated. Carbohydrate is the main content in the fouling deposit. The morphology of the deposit was studied using SEM and it showed an aggregated structure. The cleaning process improved as the temperature increased with the increasing of the chemical solution concentration. The shortest cleaning time was 40 minutes, for cleaning using 2.0 v/v % of Maxiclean CP6 (0.44 % OH-) at 90°C.
Field investigation on the operation of an industrial fluidized bed paddy dryer of 25 t/h capacity available in a processing complex of Padiberas Nasional Berhad (BERNAS) of Malaysia was carried out to assess its drying characteristics, energy consumption and quality of product during two paddy harvesting seasons. A grain drying simulation model was used to predict dryer performance which can be used as a basis for improving drying operations. For the first season (August-September), average drying rate was found to be 538 kg moisture/h to reduce moisture content (mc) from 36.98± 0.89% dry basis (db) to 27.58±0.79% (db) at 100-120°C of drying air temperature with a feed rate (capacity) of 7.75 t/h. In the second season (February-March), average drying rate was found to be 435 kg moisture/h to reduce mc from 28.14 ±0.68% (db) to 22.54 ± 0.69% (db) at 78-90°C drying air temperature with a feed rate of 9.5 t/h. The thermal and electrical energy consumptions were obtained as 7.57 and 0.97 MJ/kg water removed, respectively, for the first season, while 5.92 and 1.2 MJ/kg water removed for the second season. Higher head rice yield and whiteness and lower milling recovery were achieved during the first season than the second season at acceptable milling degree and transparency. Meanwhile, simulation results indicated that the dryer performed better in terms of increased drying capacity during the second than the first season; the dryer could be operated at 150°C to achieve almost double throughput capacity up to 20 t/h for the second season, while for the first season, high mc hindered the capacity to be at or below 7.75 t/h even when using higher a temperature of 160°C to reduce moisture to the desired final moisture of 24-25% (db). Proportion of slower vehicles based on users' opinion poll