The effect of surface treatment on composite interface, tensile properties and water absorption of suger palm fiber/polypropylene composites

The rising concern towards environmental issues besides the requirement for more flexible polymer-based material has led to increasing of interest in studying about green composite. Sugar palm fiber (SPF) is a versatile fiber plant employed with wide range of application such as in automotive, packaging and buildings construction. This research was aimed to study the effect of surface treatment on composite interface, tensile properties and water absorption of sugar palm fiber/polypropylene (SPFPP) composite by using different surface treatments such as silane (Si), atmospheric glow discharge plasma (Agd) and maleic anhydride (Ma). Silane treatment was carried out by using immersion method, the Agd plasma was conducted using polymerization and lastly polypropylene grafted maleic anhydride by using melting approach. The SPFPP composite was prepared by using injection moulding with fiber content var­ied from 10-30wt%. The effect of interface enhancement on morphology, mechanical properties and water uptakes of SPFPP composites were then investigated by using FfIR, FESEM, tensile test and water absorption test. Overall, the outcome shows that aJl types of surface treatments had improved the interface of SPFPP composite, thus improving its tensile properties compared to the benchmark untreated SPFPP (Ut­SPFPP) composites and polypropylene. The 30wt% Ma-SPFPP composite shows the highest improvement in tensile properties with 58% and 27% increase in the respective Young's Modulus and tensile strength value compared to Ut-SPFPP composite, while 10wt% Ma-SPFPP composite shows the smallest reduction in elongation compared to Neat PP. On the other hand, the 30wt% Si-SPFPP composite shows the lowest water absorption with 20% reduction respective to Ut-SPFPP composite. In conclusion, the surface treatments have proven succesfull in enhancing the natural fiber-polymer in­terface and improve the tensile properties of SPFPP composite with Ma-SPFPP shows the highest improvement, foJlowed by Agd-SPFPP and Si-SPFPP composites

The effect of surface treatment on composite interface, tensile properties and water absorption of suger palm fiber/polypropylene composites

The rising concern towards environmental issues besides the requirement for more flexible polymer-based material has led to increasing of interest in studying about green composite. Sugar palm fiber (SPF) is a versatile fiber plant employed with wide range of application such as in automotive, packaging and buildings construction. This research was aimed to study the effect of surface treatment on composite interface, tensile properties and water absorption of sugar palm fiber/polypropylene (SPFPP) composite by using different surface treatments such as silane (Si), atmospheric glow discharge plasma (Agd) and maleic anhydride (Ma). Silane treatment was carried out by using immersion method, the Agd plasma was conducted using polymerization and lastly polypropylene grafted maleic anhydride by using melting approach. The SPFPP composite was prepared by using injection moulding with fiber content var­ied from 10-30wt%. The effect of interface enhancement on morphology, mechanical properties and water uptakes of SPFPP composites were then investigated by using FfIR, FESEM, tensile test and water absorption test. Overall, the outcome shows that aJl types of surface treatments had improved the interface of SPFPP composite, thus improving its tensile properties compared to the benchmark untreated SPFPP (Ut­SPFPP) composites and polypropylene. The 30wt% Ma-SPFPP composite shows the highest improvement in tensile properties with 58% and 27% increase in the respective Young's Modulus and tensile strength value compared to Ut-SPFPP composite, while 10wt% Ma-SPFPP composite shows the smallest reduction in elongation compared to Neat PP. On the other hand, the 30wt% Si-SPFPP composite shows the lowest water absorption with 20% reduction respective to Ut-SPFPP composite. In conclusion, the surface treatments have proven succesfull in enhancing the natural fiber-polymer in­terface and improve the tensile properties of SPFPP composite with Ma-SPFPP shows the highest improvement, foJlowed by Agd-SPFPP and Si-SPFPP composites

Task-space dynamic control of underwater robots

This thesis is concerned with the control aspects for underwater tasks performed by marine robots. The mathematical models of an underwater vehicle and an underwater vehicle with an onboard manipulator are discussed together with their associated properties. The task-space regulation problem for an underwater vehicle is addressed where the desired target is commonly specified as a point. A new control technique is proposed where the multiple targets are defined as sub-regions. A fuzzy technique is used to handle these multiple sub-region criteria effectively. Due to the unknown gravitational and buoyancy forces, an adaptive term is adopted in the proposed controller. An extension to a region boundary-based control law is then proposed for an underwater vehicle to illustrate the flexibility of the region reaching concept. In this novel controller, a desired target is defined as a boundary instead of a point or region. For a mapping of the uncertain restoring forces, a least-squares estimation algorithm and the inverse Jacobian matrix are utilised in the adaptive control law. To realise a new tracking control concept for a kinematically redundant robot, subregion tracking control schemes with a sub-tasks objective are developed for a UVMS. In this concept, the desired objective is specified as a moving sub-region instead of a trajectory. In addition, due to the system being kinematically redundant, the controller also enables the use of self-motion of the system to perform sub-tasks (drag minimisation, obstacle avoidance, manipulability and avoidance of mechanical joint limits)

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties

Task priority control of underwater intervention systems: Theory and applications

This paper presents a unifying task priority control architecture for underwater vehicle manipulator systems. The proposed control framework can be applied to different operative scenarios such as waypoint navigation, assisted teleoperation, interaction, landing and grasping. This work extends the results of the TRIDENT and MARIS projects, which were limited to the execution of grasping actions, to other applications taken from the DexROV and ROBUST projects. In particular, simulation results show how the control framework can be used, for example, for pipeline inspection scenarios and deep sea mining exploration

Underwater Robots Part II: Existing Solutions and Open Issues

National audienceThis paper constitutes the second part of a general overview of underwater robotics. The first part is titled: Underwater Robots Part I: current systems and problem pose. The works referenced as (Name*, year) have been already cited on the first part of the paper, and the details of these references can be found in the section 7 of the paper titled Underwater Robots Part I: current systems and problem pose. The mathematical notation used in this paper is defined in section 4 of the paper Underwater Robots Part I: current systems and problem pose