Reducing machining time in a milling process is one of the important criteria to improve the overall efficiency of the machining process. This paper presents a study on the reduction of machining ...time, focusing on contour parallel machining to increase the efficiency and performance during the machining process. One method to enhance the performance of contour parallel machining is by defining a tool path interval that is larger than the radius of the cutting tool in a roughing operation because of its capability of reducing the tool path length and machining time. However, this causes the occurrence of an uncut region at the corner and at the centre of a contour parallel. This uncut region can be removed through an additional tool path known as the clear tool path. Therefore, in this paper, a new method based on an optimisation technique is introduced to generate a clear tool path that removes the entire uncut region in contour parallel machining at minimum cutting time. Ant colony algorithm (ACO) is used to optimise the clear tool path length in contour parallel machining time by minimising the movement of cutting tool in removing the entire uncut regions. A new transition rule has been established from the conventional ACO, which adapted the uncut region occurring at the corner of the contour parallel. Then, to validate the optimisation result, a cutting experiment was carried out using computer numerical control (CNC) milling machine. It can be ascertained from this study that the optimisation of the clear tool path gives optimal tool path length whilst reducing the cutting time in the roughing process.
Abstract
The 2030 Agenda for Sustainable Development Goals SDGs with its universal, integration, and inclusivity principles, is a commitment to promote sustainable development in accordance with ...human rights and equality to encourage social, economic, and environmental development and ensuring that “no-one left behind”. SDGs also promotes six pivotal elements: planet, people, dignity, prosperity, justice, and partnership. This research examines that since Indonesia has committed to reach and implement SDGs into the National Medium-Term Development Plan, the number of environmental and human rights issues has increased. In particular, the issues of the arrest of indigenous groups that try to protect their lands from land clearing for palm oil companies or infrastructure development that build their business by destroying the natures or homes of the indigenous groups. The issues are closely related to Goal 5, 10, 11, and 13-16. This shows the inconsistency of the Indonesian government in implementing the SDGs. Thus, this paper argues that to reach the goals, the Indonesian government has to acknowledge indigenous groups that play pivotal roles in preserving the environment, through local regulation
Abstract
As a result of the emergence of two-dimensional (2D) materials for various opto-electronics applications, a new class of materials named MXenes have been attracting interests due to their ...outstanding nonlinear properties. In this work, an MXene niobium carbide (Nb
2
C) was proposed and demonstrated as a saturable absorber to induce mode-locking in thulium- and thulium/holmium-doped fiber lasers. The Nb
2
C solution was first prepared using the liquid exfoliation technique, and then deposited onto a microfiber for integration into the laser cavity. Stable mode-locking operation was observed in both laser cavities, where the center wavelengths of the laser were recorded at 1944 nm for the TDFL and 1950 nm for the THDFL. The generated pulses in the TDFL and THDFL had repetition rates of 9.35 and 11.76 MHz respectively, while their corresponding pulse widths were 1.67 and 1.34 ps. Both of the lasers were highly stable, having SNR values of more than 52 dB and showed no major fluctuations when tested for their long-term stabilities. The results demonstrate an excellent performance of the Nb
2
C as a saturable absorber, offering opportunities to further explore MXenes for future photonics devices.
Brain image segmentation is one of the most important parts of clinical diagnostic tools. Brain images mostly contain noise, inhomogeneity and sometimes deviation. Therefore, accurate segmentation of ...brain images is a very difficult task. However, the process of accurate segmentation of these images is very important and crucial for a correct diagnosis by clinical tools. We presented a review of the methods used in brain segmentation. The review covers imaging modalities, magnetic resonance imaging and methods for noise reduction, inhomogeneity correction and segmentation. We conclude with a discussion on the trend of future research in brain segmentation.
Abstract
In this work, mode-locked thulium-doped fiber lasers operating in the 2 µm wavelength region were demonstrated using tantalum aluminum carbide (Ta
2
AlC)-based saturable absorbers (SAs) ...utilizing the evanescent wave interaction. The Ta
2
AlC MAX Phase was prepared by dissolving the Ta
2
AlC powder in isopropyl alcohol and then deposited onto three different evanescent field-based devices, which were the tapered fiber, side-polished fiber, and arc-shaped fiber. Flame-brushing and wheel-polishing techniques were used to fabricate the tapered and arc-shaped fibers, respectively, while the side-polished fiber was purchased commercially. All three SA devices generated stable mode-locked pulses at center wavelengths of 1937, 1931, and 1929 nm for the tapered, side-polished, and arc-shaped fibers. The frequency of the mode-locked pulses was 10.73 MHz for the tapered fiber, 9.58 MHz for the side-polished fiber, and 10.16 MHz for the arc-shaped fiber. The measured pulse widths were 1.678, 1.734, and 1.817 ps for each of the three SA devices. The long-term stability of the mode-locked lasers was tested for each configuration over a 2-h duration. The lasers also showed little to no fluctuations in the center wavelengths and the peak optical intensities, demonstrating a reliable, ultrafast laser system.
Many anatomical variations of the middle turbinate (MT), including pneumatized, paradoxically curved, bifurcate, trifurcate, secondary, and accessory, have been described. The most common is ...pneumatized MT (concha bullosa), but other less common variations may also impact the outcome of clinical management. Anatomical variations of the MT, particularly with a concomitant deviated nasal septum, tend to obstruct the middle meatus leading to disruption of the normal sinus drainage and worsening the symptoms of rhinosinusitis. By recognizing the unique anatomical variant by endoscopy or imaging will help us to improve the management. We report an endoscopic presentation of a rare accessory MT.
The purpose of this research is to measure and analyze the properties of activated carbon from biomass waste of palm oil empty fruit bunch by using x-ray diffraction (XRD). Biomass waste that has ...been clean and dried is carbonated at 400°C for 10 minutes to produce charcoal. Next, the charcoal is activated through a chemical process with the activating agent NaOH by soaking it for twelve hours. Activated carbon with 2N activated agent NaOH have the best properties because it has a largest surface area (27.07). The results of this research are useful for technological developments of activated carbon, and provide an economic added value to biomass waste.
This study proposing an environmentally friendly and lead (Pb)-free alternative in the form of electrospun mats of Bi
2
O
3
/WO
3
/PVA for X-ray shielding. By varying Bi
2
O
3
filler loading (0–20 ...wt%) while keeping WO
3
filler constant at 10 wt%, the study examined density, thickness, and mass attenuation coefficient (µ) of the fabricated mats. X-ray attenuation was evaluated across different X-ray energy levels (16.61–25.27 keV) using X-ray fluorescence (XRF) unit. Meanwhile, the surface morphology and nanoparticle dispersion within the PVA nanofiber mat were observed through Field Emission Scanning Electron Microscope (FESEM). Results demonstrated improved X-ray attenuation with increased Bi
2
O
3
filler loadings, except for mats containing 20 wt% Bi
2
O
3
and 10 wt% WO
3
(mat B5) due to coagulation and porosity issues. The electrospun mat with 15 wt% Bi
2
O
3
and 10 wt% WO
3
(mat B4) exhibited the highest X-ray attenuation. Thus, electrospun mat B4 is proposed as a promising candidate for environmentally friendly X-ray shielding material.
The objective detection of muscle fatigue reports the moment at which a muscle fails to sustain the required force. Such a detection prevents any further injury to the muscle following fatigue. ...However, the objective detection of muscle fatigue still requires further investigation. This paper presents an algorithm that employs a new fatigue index for the objective detection of muscle fatigue using a double-step binary classifier. The proposed algorithm involves analyzing the acquired sEMG signals in both the time and frequency domains in a double-step investigation. The first step involves calculating the value of the integrated EMG (IEMG) to determine the continuous contraction of the muscle being investigated. It was found that the IEMG value continued to increase with prolonged muscle contraction and progressive fatigue. The second step involves differentiating between the high-frequency components (HFC) and low-frequency components (LFC) of the EMG, and calculating the fatigue index. Basically, the segmented EMG signal was filtered by two band-pass filters separately to produce two sub-signals, namely, a high-frequency sub-signal (HFSS) and a low-frequency sub-signal (LFSS). Then, the instantaneous mean amplitude (IMA) was calculated for the two sub-signals. The proposed algorithm indicates that the IMA of the HFSS tends to decrease during muscle fatigue, while the IMA of the LFSS tends to increase. The fatigue index represents the difference between the IMA values of the LFSS and HFSS, respectively. Muscle fatigue was found to be present and was objectively detected when the value of the proposed fatigue index was equal to or greater than zero. The proposed algorithm was tested on 75 EMG signals that were extracted from 75 middle deltoid muscles. The results show that the proposed algorithm had an accuracy of 94.66% in distinguishing between conditions of muscle fatigue and non-fatigue.
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