Hot-air contactless single-point incremental forming

Single-point incremental forming (SPIF) has emerged as a time-efficient approach that offers increased material formability compared to conventional sheet-metal forming techniques. However, the physical interaction between the forming tool and the sheet poses challenges, such as tool wear and formability limits. This study introduces a novel sheet-forming technique called contactless single-point incremental forming (CSPIF), which uses hot compressed air as a deformation tool, eliminating the requirement for physical interaction between the sheet and a rigid forming tool. In this study, a polycarbonate sheet was chosen as the case-study material and subjected to the developed CSPIF. The experiments were carried out at an air temperature of 160 °C, air pressure of 1 bar, a nozzle speed of 750 mm/min, and a step-down thickness of 0.75 mm. A Schlieren setup and a thermal camera were used to visualize the motion of the compressed hot air as it traveled from the nozzle to the sheet. The results showed that the CSPIF technique allowed for the precise shaping of the polycarbonate sheet with minimal springback. However, minor deviations from the designed profile were observed, primarily at the starting point of the nozzle, which can be attributed to the bending effects of the sample. In addition, the occurrence of sheet thinning and material buildup on the deformed workpiece was also observed. The average surface roughness (Ra) of the deformed workpiece was measured to be 0.2871 micron

Optimisation of a novel hot air contactless single incremental point forming of polymers

This study presents a new contactless sheet forming method that utilises hot air as a forming tool to address tool wear challenges in single-point incremental forming. Experiments were conducted on a 3-axis CNC machine equipped with a hot air nozzle on a polycarbonate sheet. A design of experiment (DOE) approach was employed, evaluating five control factors: air pressure, air temperature, feed rate, tool offset, and step down. The evaluation criteria for the formed sheets are profile variation, thickness variation, and surface roughness. The results indicate that air temperature and feed rate have the most significant influence on the deformation process. Additionally, air pressure and feed rate substantially impact both thickness variation and surface roughness of the formed material. To optimise the process parameters for high-quality forming, a prediction model is developed. The optimised process shows good agreement with the predicted model regarding profile and thickness variations. However, it does not align with surface roughness due to the stepwise nature and inherent waviness of the contactless forming technique. This study offers a promising approach for developing innovative contactless forming techniques using hot pressurised air as a forming tool. The proposed technique has the potential to significantly reduce tool wear and lubrication requirements

Cu2+ Montmorillonite K10 Clay Catalyst as a Green Catalyst for Production of Stearic Acid Methyl Ester: Optimization Using Response Surface Methodology (RSM)

Clay catalyst has received much attention to replace the homogeneous catalysts in the esterification reaction to produce fatty acid methyl ester as the source of biodiesel as it is low cost, easily available, as well as environmental friendly. However, the use of unmodified clay, in particular montmorillonite K10 (MMT K10), for the esterification of fatty acids showed that the acid conversion was less than 60% and this is not preferable to the production of biodiesel. In this study, synthesis of stearic acid methyl ester using Cu2+-MMT K10 (Cu-MMT K10) was successfully optimized via response surface methodo-logy (RSM) based on 3-variable of Box-Behnken design (BB). The parameters were; reaction time (5-180 minutes), reaction temperature (80-120 oC) and concentration of Cu2+ in MMT K10 (0.25-1 M). The use of RSM in optimizing the conversion of stearic acid was successfully developed as the actual experimental conversion of stearic acid was found similar to the actual values under the optimum conditions. The model equation predicted that the following conditions would generate the maximum conversion of stearic acid (87.05 %reaction time of 62 minutes, a reaction temperature of 80 oC and catalyst used is 1.0 M Cu-MMT K10. This finding can be considered as green catalytic process as it worked at moderate reaction temperature using low cost clay catalyst with a short reaction time.

PEMETAAN POTENSI DAERAH UNTUK PENGEMBANGAN SMK MASA DEPAN

Tujuan penelitian ini adalah (i) untuk mengetahui seberapa besar relevansi keberadaan SMK dengan potensi daerah yang ada. (ii) Untuk mengetahui sumber daya alam dan sumber daya manusia yang ada di daerah tersebut. (iii) untuk mengetahui prospek pengembangan SMK masa depan yang berbasis potensi lokal di kabupaten Bone. Jenis penelitian ini adalah penelitian deskriptif dengan menggunakan metode survei dalam mengumpulkan data untuk mengungkap fenomena tentang relevansi SMK terhadap potensi daerah serta menggambarkan potensi daerah yang ada di wilayah tersebut dan sebagai prospek pengembangan SMK masa depan yang berbasis potensi daerah. Teknik pengumpulan data yang digunakan adalah observasi, penyebaran angket, wawancara dan data dokumentasi yang dibutuhkan. Hasil penelitian ini menunjukkan bahwa (i) keberadaan SMK saat ini masih belum relevan dengan potensi daerah yang ada. (ii) gambaran pemetaan potensi daerah diuraikan dalam setiap kecamatan yang ada di Kabupaten Bone, serta (iii) prospek pengembangan SMK masa depan yang paling besar di Kabupaten Bone adalah SMK pertanian

Vehicular Visible Light Positioning using Receiver Diversity with Machine Learning

This paper proposes a 2-D vehicular visible light positioning (VLP) system using existing streetlights and diversity receivers. Due to the linear arrangement of streetlights, traditional positioning techniques based on triangulation or similar algorithms fail. Thus, in this work, we propose a spatial and angular diversity receiver with machine learning (ML) techniques for VLP. It is shown that a multi-layer neural network (NN) with the proposed receiver scheme outperforms other ML algorithms and can offer high accuracy with root mean square (RMS) error of 0.22 m and 0.14 m during the day and night time, respectively. Furthermore, the NN shows robustness in VLP across different weather conditions and road scenarios. The results show that only dense fog deteriorates the performance of the system due to reduced visibility across the road

Evaluation of The Quality of E-Learning Platforms Used in Educating Kindergarten Children Distantly During the Coronavirus Pandemic

During the coronavirus pandemic, and for the first time, ministries of education in many countries have resorted to electronic education platforms for kindergarten children as a safe alternative to face-to-face education. This shift to distance education is still used partly in the education process, even after the end of the pandemic. The current study aimed to consider this unique experience by evaluating the quality of the Rawdaty platform, which is one of the e-learning platforms launched by the Saudi Ministry of Education during the coronavirus pandemic, to ensure the continuation of the educational process in kindergartens. The analytical descriptive approach was used, and a scale derived from the Saudi National E-Learning Center (NELC) standards was designed to achieve the studys objectives. The scale includes four main dimensions: Design, Interaction, Equity and accessibility, Measurement and Evaluation. The research sample consisted of (94) mothers and (67) kindergarten teachers. The results of the study were as follows: The quality standards of the Rawdaty platform were achieved to a high degree from the point of view of mothers, with an arithmetic mean of (55.93) and an average weight of (2.664). It also showed the high-quality standards of the kindergarten platform from the point of view of the teachers, with an arithmetic mean of (58.35) and an average weight of (2.78). The study recommended the possibility of adopting e-learning platforms to teach kindergarten children distantly during exceptional circumstances

Efficient 3D trilateration algorithm for visible light positioning

© 2019 IOP Publishing Ltd. This letter presents an efficient algorithm for estimating the three-dimensional (3D) location of a photodiode (PD) receiver via visible light positioning. It solely works on measured powers from different light-emitting diode (LED) sources and does not require any prior knowledge of the PD receiver height. It is found that four LEDs are required that are not on the same circle, in order to unambiguously determine the 3D location. The algorithm is optimized towards a minimized calculation time in view of real-time operation on energy-constrained lightweight and mobile devices such as drones

Innovative Blockchain-Based Applications - State of the Art and Future Directions

Recently, blockchain technology has increasingly being used to provide a secure environment that is immutable, consensus-based and transparent in the finance technology world. However, significant efforts have been made to use blockchain in other fields where trust and transparency are required. The distributed power and embedded security of blockchain leverage the operational efficiency of other domains to be immutable, transparent, and trustworthy. The trust of the published literature in blockchain technology is centered on crypto-currencies. Therefore, this paper addresses this gap and presents to the user several applications in many fields, including education, health, carbon credits, robotics, energy, pharmaceutical supply chains, identity management, and crypto-currency wallets. This paper overviews the knowledge on blockchain technology, discusses the innovation of blockchain technology based on the number of applications which have been introduced, describes the challenges associated with blockchain technology, and makes suggestions for future work