Stainless Steel Cyclic Voltammograms in Dioscorea Opposita Flour Media

Improving the efficiency of hydrogen gas production in the water electrolysis process draws great attention from many scholars. To improve the efficiency of the process and reduction in the cost, stainless steel has been widely implemented in the industrial water electrolysis process. Electrolyte modification is also one of the methods to improve the water electrolysis process. The study used Dioscorea opposita tuber flour as a media addition in an alkaline solution. The efficiency of water electrolysis was evaluated by cyclic voltammetry. The result showed that the activity of the electrode and energy consumption were increased with values of 29 and 23%, respectively, by adding 3 g of the media. However, no media addition showed the lowest energy consumption regarding overpotential value. In general, the Dioscorea opposita tuber flour tends to cover the electrode and reduce the activity. Moreover, the utilization of wastewater from Dioscorea opposita flour industry is still beneficial to produce hydrogen gas instead of using freshwater.

Location Suitability Analysis for Wind Farm Exploitation Using Fuzzy Analytic Hierarchy Process

The development of renewable energy has been constantly conducted as an attempt to increase energy diversification, improve energy sustainability and reduce greenhouse gas emissions, including the wind power plant (WPP). Suitable location selection is urgently necessary to achieve optimized output and high economic values. There are multi-criteria to be considered during the selection process, namely wind velocity, climate condition, road access, environmental impact, land use, land tilt, plain condition, distance to residential areas, etc. This study aimed to develop a software supporting multi-criteria decision-making based on artificial intelligent technology, namely fuzzy analytic hierarchy process (fuzzy-AHP) which was implemented to evaluate the WPP location suitability. The method of fuzzy-AHP is believed to be able to generate prioritized criteria supporting the location of WPP with high accuracy. Based on those criteria, there were two locations identified at Tanah Laut Regency, South Kalimantan, Indonesia, as the most suitable research sites. It is expected that studies employing fuzzy-AHP are to be further developed to determine wider renewable WPP locations.

Numerical Study and Theoretical Comparison of Outlet Hole Geometry for a Gravitational Vortex Turbine

The gravitational water vortex turbine is an alternative to renewable energies, it transforms the hydrokinetic energy of the rivers into electric energy and it does not require a reservoir. According to studies carried out, the hydraulic efficiency can increase or decrease according to the turbine geometrical configuration. This paper presents a numerical (CFD) and analytical comparison between conical and cylindrical designs for the outlet. The results show a higher performance for conical geometry than the cylindrical tank. The fluid behavior in CFD and analytical studies presents a tangential velocity increase near to air core and outlet hole (similar behavior). The maximum theoretical power generated was 167 W and 150 W for conical and cylindrical design respectively. The differences between geometries of the outlet holes using CFD and analytical models were 11 and 7%, respectively. However, the closest results to the CFD model had different values of 31 and 29% for conical and cylindrical design, respectively. The furthest result regarding the CFD study was 55%. The principal difference is due to tank geometry, the change in discharge zone, as well as the ratio of diameter tank and outlet hole can increase or decrease the tangential velocity and make a stronger and more stable vortex formation. The theoretical power generated is a good parameter to select the height to place the rotor.

Chatbot-Based Application Development and Implementation as an Autonomous Language Learning Medium

Autonomous learning has an important role in online learning because teachers cannot directly supervise the student learning process, which makes students themselves responsible for their learning. As an attempt to provide teachers with an alternative autonomous learning medium, this study aimed to use a chatbot-based Japanese grammar learning application namely Gengobot as an autonomous Japanese learning medium. This study applied Analysis, Design, Development, Implementation, and Evaluation (ADDIE) instructional design model. The data of this research was collected using a pre-experimental method and distributed a Likert scale questionnaire to 50 Japanese language learners with Japanese language levels equivalent to or less than JLPT level N3. The results showed that Gengobot as a chatbot-based Japanese grammar learning medium is an interesting and innovative medium to support Japanese autonomous learning because learners can decide how they learn using this application to improve their Japanese grammar skills. In addition, Gengobot is a chatbot-based learning medium that is more interactive than other Mobile-based media, which makes learners more interested in using Gengobot as a Japanese grammar learning medium. However, Gengobot still needs further development such as adding advanced grammar content (N2 and N1), adding Japanese pronunciation features (audio), etc.

Finite-Time Control of Wing-Rock Motion for Delta Wing Aircraft Based on Whale-Optimization Algorithm

The rise of wing-rock motion in delta-wing aircraft has an adverse effect on the manoeuvrability of aircraft and it may result in its crash. This study presents a finite-time control design to tackle the dynamic motion due to the Wing-Rock effect in delta-wing aircraft. The control design is developed based on the methodology of Super Twisting Sliding Mode Control (STSMC). The Lyapunov stability analysis has been pursued to ensure asymptotic convergence of errors and to determine the finite time. The design of STSMC leads to the appearance of design parameters, which have a direct impact on the dynamic performance of the controlled system. To avoid the conventional tuning of these parameters and to have an optimal performance of the proposed controller, a modern optimization technique has been proposed based on Wale Optimization Algorithm. A comparison study between optimal and non-optimal finite-time super twisting sliding mode controllers has been established and their effectiveness has been verified via numerical simulation using MATLAB programming format.

Length-weight relationship and condition factor of Trachurus trachurus found in the central-east region of the Moroccan Mediterranean

Trachurus trachurus, is a migratory, semi-pelagic species of the Carangidae family living in schools often associated with mackerel. This species is very common in the Mediterranean, and it is found on all Moroccan coasts. This study aims to determine the length-weight relationship and the condition factor (K) of Trachurus trachurus. Thus, 390 specimens were collected between August 2017 and August 2018 in the central-east region of the Moroccan Mediterranean. The parameters of the length-weight relationship were determined and analyzed by length and sex. It appears that this species has better growth in length than in weight, therefore having a negative or lower allometry. It varies according to sex, length, and season. This result shows that Trachurus trachurus in this study is not overweight in its habitat.

Investigation of Compressive Behavior of Pre-folded Thin-walled Column Fabricated by 3D Printing

This paper reveals the mechanical behavior of thin-walled columns with pre-folded patterns subjected to compressive loading. The column specimens (Polylactic Acid) are fabricated using Fused Deposition Modeling 3D printer and subjected to quasi-static compressive loading to investigate their mechanical behavior (by modifying the specimens' cross-section patterns and folding angles). The column specimens are simulated by finite element analysis to understand how the stress distribution and local deformation affecting the stiffness, strength, and overall deformation. The experiments showed that introducing the pre-folded pattern in a thin-walled column with different cross-sections can dramatically lower its structural stiffness (85%) and compressive strength (69%), but increase its deformability (115%), which is good agreement with numerical simulation. The variation of cross-section patterns and pre-folding angle could effectively modify the compressive mechanical behavior. Moreover, the results demonstrate how the FDM 3D Printing method can be used in fabricating a thin-walled column with irregular shapes and then to modify its deformability. This finding can be useful for designing any complex structures requiring specific stiffness and deformation such as suspension devices, prosthetic devices in biomechanics, and robotic structures.

Progress in Emerging Contaminants Removal by Adsorption/Membrane Filtration-Based Technologies: A Review

This paper discussed the removal and the remediation of emerging contaminants (ECs) in water using adsorption and membrane filtration as a single and hybrid system. The classifications, sources, effects, detection techniques, and available technologies for ECs removal were discussed. Next, an overview of both adsorption and membrane filtration processes in terms of materials, separation mechanisms, factors affecting their performances, and their applications for ECs removals was provided. It was followed by a comprehensive review of the combination of the membrane and the adsorption processes with other physical, chemical, or biological treatments. Finally, progress in research on a hybrid system between membrane filtration and adsorption was discussed. The combination included adsorption as the pre-treatment, integrated adsorption/membrane filtration system, or adsorption as the post-treatment. Generally, the hybrid systems showed improved performance than a single system. Nonetheless, further studies are recommended for applications of those systems on a wide range of ECs removals and the scale-up issue.

The Concise Latest Report on the Advantages and Disadvantages of Pure Biodiesel (B100) on Engine Performance: Literature Review and Bibliometric Analysis

Currently, many countries are promoting B100 as the main fuel for diesel engines towards the transition to 100% renewable energy applications. However, due to its properties, B100 has both advantages and disadvantages to replace diesel oil. Therefore, a bibliometric analysis was carried out to evaluate the performance and emissions of a diesel engine with the B100 being tested on a multi-cylinder diesel engine for cars. Unfortunately, only 12 of the 127 selected articles are eligible to be reviewed in detail and none of them discusses all the key performance of diesel engines which include Brake Thermal Efficiency (BTE), Specific Fuel Consumption (SFC), Cylinder Pressure (CPs), Heat Release Rate (HRR), NOx, and smoke. Through data synthesis, we found that the use of B100 provides advantages in engine noise, thermal efficiency, specific fuel consumption, and emissions under certain engine loads. On the other hand, it also has the potential to result in poorer performance, if there is no modification to engine components and the addition of additives. As a recommendation, the results of this analysis provide a guide for further research to examine the use of B100 with all diesel engine performance variables. Research paths can be developed with the wider potential to provide new arguments on various diesel engine technologies, engine capacities, B100 raw materials, and test environments.

Immersive Intelligent Tutoring System for Remedial Learning Using Virtual Learning Environment

Intelligent Tutoring System (ITS) has been widely used in supporting personal learning. However, there is an aspects that have not become focus in ITS, namely immersive. This research proposes an Immersive Intelligent Tutoring (IIT) model based on Bayesian Knowledge Tracing (BKT) for determining the learner’s characteristics and learning content delivery strategies using genetic algorithms. The model uses remedial learning with a faded worked-out example. This study uses a 3-Dimensional Virtual Learning Environment (3DMUVLE) that implements immersive features to increase intrinsic motivation. This model was built using a client / server architecture. The server side component uses the MOODLE, the client side component uses OpenSim and its viewers, and the middleware component uses the Simulation Linked Object Oriented Dynamic Learning Environment (SLOODLE). Model testing is performed on user acceptance using a combination of Technology Acceptance Model (TAM) and Hedonic-Motivation System Adoption Model (HMSAM) and the impact of the model in learning using statistical test. The results showed 83% of the learners felt happy with the learning. Meanwhile, the evaluation of the impact on learning outcomes shows that the use of this model is significantly different from traditional learning.