Biodiesel from green energy source is gaining tremendous attention for ecofriendly and economically aspect. In this investigation, a two-step process was developed for the production of biodiesel from microalgae Spirulina maxima and determined best operating conditions for the steps. In the first stage, acid esterification was conducted to lessen acid value (AV) from 10.66 to 0.51 mgKOH/g of the feedstock and optimal conditions for maximum esterified oil yielding were found at molar ratio 12:1, temperature 60 C, 1% (wt%) H 2 SO 4 , and mixing intensity 400 rpm for a reaction time of 90 min. The second stage alkali transesterification was carried out for maximum biodiesel yielding (86.1%) and optimal conditions were found at molar ratio 9:1, temperature 65 C, mixing intensity 600 rpm, catalyst concentration 0.75% (wt%) KOH for a reaction time of 20 min. Biodiesel were analyzed according to ASTM standards and results were within standards limit. Results will helpful to produce third generation algal biodiesel from microalgae Spirulina maxima in an efficient manner.

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This paper presents the development of SignBot, a 3D printed robot which can perform Malaysian Sign Language (MSL). This work is the first attempt to eliminate the barriers of communication between hearing impaired individuals and the mainstream society as it is the first robot to perform MSL. The signing, in this work, can be done with two hands. The robot hands were developed with detailed finger joints. Micro servo motors were installed to allow for the signing motions for the relevant joints of selected letters, numbers as well as phrases for emergency cases. The sequential movements of the servo motor arrays are stored in the database to represent particular signs, and retrieved by the microcontroller based on the speech input detected, and finally executed accordingly by the servo motors to perform the sign. © Springer International Publishing AG, part of Springer Nature 2019. Indexed keywords

Structural optimisation of robotic manipulators is critical for any manipulator used in confined semi-structured environments, such as in agriculture. Many robotic manipulators utilised in semi-structured environments retain the same characteristics and dimensions as those used in fully-structured industrial environments, which have been proven to experience low dexterity and singularity issues in challenging environments due to their structural limitations. When implemented in environments other than fully-structured industrial environments, conventional manipulators are liable to singularity, joint limits and workspace obstacles. This makes them inapplicable in confined semi-structured environments, as they lack the flexibility to operate dexterously in such challenging environments. In this paper, structural optimisation of a hyper-redundant cable-driven manipulator is proposed to improve its performance in semi-structured and challenging confined spaces, such as in agricultural settings. The optimisation of the manipulator design is performed in terms of its manipulability and kinematics. The lengths of the links and the joint angles are optimised to minimise any error between the actual and desired position/orientation of the end-effector in a confined semi-structured task space, as well as to provide optimal flexibility for the manipulators to generate different joint configurations for obstacle avoidance in confined environments. The results of the optimisation suggest that the use of a redundant manipulator with rigid short links can result in performance with higher dexterity in confined, semi-structured environments, such as agricultural greenhouses.