Abstract: The purpose of the sago starch extraction process is to remove maximum amount of fibre possible from the starch and to obtain the maximum amount of starch. The efficiency of the extraction depends on how carefully the operation is managed. The starch separation mechanism is combination of kneading and screening by assistance of water. The objective of this study was to develop and test the performance of vertical stirrer rotary blade sago starch extraction machine. In the experiment, three levels of extraction time duration i.e. 10, 15 and 20 minutes, and three levels of water inflow rate i.e. 100, 150 and 200 litres per minute were examined. The extractor performance test was carried out by measuring extraction capacity, starch percentage, starch yield, and starch left in sago pith waste. Results showed that extraction capacity, starch yield and starch left in waste were decreased as time duration increased. Meanwhile, starch percentage was increased as time duration increased. Likewise, starch percentage and starch yield increased with the increase water inflow rate, while starch left in waste decreased. However, unlike others parameter, extraction capacity was constant as water inflow rate increased. The highest performance was obtained at the condition of extraction time duration of 10 minutes with water inflow rate was 200 litres per minute. The performance at the condition were (1) extraction capacity 533 kg/hour, (2) starch percentage 34%, (c) starch yield 182 kg/hour and starch left in waste 1%.In conclusion, the developed sago starch extraction machine resulted in this study has higher performance compared to the previous prototype.

Abstract: The 3GPP in LTE-release 13 standardized the Narrowband Internet of Things (NB-IoT) technology which employs a reduced signaling overhead of 180kHz bandwidth over legacy LTE networks. This research work presents a model and an optimization of the NB-IoT Physical Random Access Channel (NPRACH). An analytical model is derived to estimate the access success probabilities and average access delays of User Equipment (UEs), in terms of parameters such as the maximum number of preamble transmissions, size of backoff windows, and number of sub-carriers in each coverage enhancement (CE) levels. An optimal parameters configuration is proposed for the model. The model is simulated under various conditions and the performance results are analyzed. The optimized ALOHA model achieves high average success probability and low latency, and can be deployed in applications with low latency budget, such as e-health and autonomous vehicles.