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Bacterial growth in food sources after harvesting and during food manufacturing has emerged as a major agricultural concern. Currently, several chemical preservatives have been added to foods to prevent or inhibit bacterial growth. These phenomena, however, become a concern when consumers begin to demand the safety of the food they consume, thus resulting in a search for natural plant extracts as an alternative. The antimicrobial activity of Cosmos caudatus leaf extract against six food pathogens was thus investigated in the present work. The disc-diffusion test, the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) tests were used to determine the antibacterial potential. Time-kill kinetics were used to determine their killing endpoints at various incubation times. Thereafter, Bacillus cereus was selected as a representative bacterium to be viewed under the light sheet electron microscope (LSEM) to observe the morphological changes. For the application as a sanitiser, different concentrations of C. caudatus extract were applied to chicken meat and oyster mushroom to determine bacterial reduction and sensory acceptability. The toxicity test using brine shrimp lethality assay was also performed to determine the toxicity level of C. caudatus extract. Results showed that C. caudatus extract contain five major peaks of flavonoids. In the antibacterial test, all tested pathogens were inhibited, with B. cereus being the most susceptible, with a significant reduction time of more than 3 log10 at 3.125 mg/mL. Under LSEM, the population of B. cereus was reduced, and the shape was wrinkled. In the application, C. caudatus extract at 0.05% for 5 min treatment time was chosen as the best formulation, whereas the brine shrimp tests showed that C. caudatus extract was safe for human consumption (LC50: 3.54 mg/mL). In conclusion, C. caudatus extract could have the potential to be further explored as a natural food sanitiser. [ABSTRACT FROM AUTHOR]

The railway track’s sub-ballast layer is important, but it is often neglected, leading to the contamination and blockage of voids, as well as track deformation and degradation. These issues occur when fouling materials infiltrate the subballast due to load-induced vibration. The purposes of this paper are to investigate the influence of vibration on the sub-ballast layer when loads are applied to a fouled ballast and to determine whether sub-ballast saturation should be ignored. A ballast box was fabricated to represent actual railway conditions and filled with 100 kg of ballast aggregates containing fouling materials (crushed ballast, sand, clay, and coal) proportional to the ballast weight. In addition, a vibratory compactor plate machine was used to simulate load on the fouled ballast, inducing vibrations that caused fouling materials to migrate into the sub-ballast. The results indicate that 18% of crushed ballast, 20% of sand, 20.7% of clay, and 15% of coal infiltrated the sub-ballast due to loading-induced vibration, and fouling infiltration percentages rose as vibration from loading increased. These percentages exceeded the standard 10% weight of fouling infiltration into the sub-ballast, indicating an unfavourable subballast condition and showing that sub-ballast saturation should not be ignored. These findings have significant implications for maintenance engineers, as they underscore the need for continuous monitoring and upkeep to ensure optimal sub-ballast performance. [ABSTRACT FROM AUTHOR]

The youth age group is a phase of life associated with risk-taking behaviour and challenging moral issues. This study aimed to provide electrophysiological evidence that could explain the interaction between attentional bias towards the health-risk of smoking and non-health risk behaviour stimuli as influenced by various levels of moral identity. Seventy eight eligible subjects (mean age of 22 ± 2.1 years old) participated in the event-related potential session. Attentional bias towards the visual stimuli was determined by recording the N200 brain potential while participants emotionally reacted to the target (health-risk of smoking, nonhealth risk behaviour) and non-target (neutral) stimuli. N200 was extracted and analysed by using a mixed-design analysis of variance with target and non-target stimuli as within subject effects and types of moral identity as between subject effects. Attentional bias towards visual stimuli interacted significantly with the different levels of moral identity in the central part of the brain. High internalisation trait indicated shorter N200 latency when reacted to the health-risk of smoking stimuli than the non-health risk behaviour stimuli. An important insight regarding to moral psychology in relation to youth health risk behaviour was highlighted to focus for the development of the health promotion and education in future. [ABSTRACT FROM AUTHOR]

This work investigates the performance of dual and quad laser wavelengths at simultaneous angle adjustment of polarization controller based on a Sagnac loop mirror interferometer. From our observation, 13 m polarization maintaining fibers of PMF length performed better in terms of lasing lines, peak power and extinction ratio of 4, −8 dBm and 38 dB, respectively. When the intensity increases, the flatness and number of channels are improved to prove that significant power setting for the best laser performance. The flatness and number of lasers are changed with the simultaneous adjustment of half-wave plate and quarter-wave plate angles. These dual and quad laser wavelengths have good power stability according to the low fluctuation below 2.25 dB of peak power difference on the laser peaks within 100 minutes. [ABSTRACT FROM AUTHOR]

The evaluation of fundamental mechanical properties of bitumen is vital to construct long-term performing pavements. This research evaluates cohesive bond strength of bitumen and mastics using compression pull-off test (CPOT). The results show problems in the common interpretation of load-displacement curves. A discussion is made on fibrillary nucleation in binder. The curing for 24 h is sufficient for the development of the cohesive bond. Furthermore, longer conditioning is needed to evaluate the moisture damage using aluminium plates. Bitumen source, grade, filler content, and loading rate affect the pull-off strength (POS). Ageing increases POS and shifts the failure mode towards brittle. The type of filler does not affect POS after short-term ageing. The moisture conditioning reduces the POS and results in a mixed to adhesive failure with increased variability in results. The aggregate plates are necessary for detailed moisture damage evaluation. The use of re-used aggregate substrate is found to be ineffective. [ABSTRACT FROM AUTHOR]

This paper attempts to find the possibility of describing the supplementary parameters of the macroscopic crack strength field based on the variation at the microscopic level. The analysis focuses on the development of cracks in the vicinity of the crack tip of a central crack panel made from iron material with a cubic crystal structure under tensile loading. We use the combination of finite element and molecular dynamics simulation methods. Molecular dynamics simulation analysis shows that the motion velocity of molecules near the crack tip region is less than the Rayleigh wave velocity, VR, which is about 0:22 VR. The average velocity is smaller in other directions that are not parallel to the crack. The velocity of the molecular near the crack tip indicates the ductile phenomenon of the crack tip region because it comes from the potential energy, which means that on the crack extension line, the kinetic energy of the molecular motion is greater than that in the other directions but is close to that in the 45° direction. It shows that the crack expansion direction is still mainly along the crack extension line under the load. [ABSTRACT FROM AUTHOR]

A bimetallic Zn–Co-ZIF derived from metal organic framework was successfully synthesized via simple co-precipitation method. The as-synthesized bimetallic MOF powder was then pyrolyzed at 600 °C, 700 °C, 800 °C, and 900 °C in N2 atmosphere, which changed the morphology and structure of the final product evidenced from field emission scanning electron microscopy and X-ray diffraction. The electrochemical results revealed that the change in elemental composition affected the specific capacity, cycling stability, and rate capability for each sample. The galvanostatic charge–discharge results showed that C600 achieved the highest specific capacity and rate capability compared to other samples heated at higher temperatures. On the other hand, C900, the sample heated at the highest temperature exhibited the best capacity retention after 50 cycles at 78% after the initial discharge whilst providing the lowest reversible discharge capacity at 45 mAh g−1. [ABSTRACT FROM AUTHOR]

The use of chemical preservatives in food products to inhibit the growth of microorganisms is widely used nowadays. However, their use has become a concern due to several negative side effects, and when consumers question the safety of the foods they eat. Therefore, the present work was conducted to investigate the potential of plant natural sanitiser from Cosmos caudatus Kunth extract to reduce the natural microflora present in raw beef and shrimp meat samples. The present work aimed to investigate the reduction of natural microflora (B. cereus, E. coli, Pseudomonas spp., S. aureus, and L. monocytogenes) in raw beef and shrimp meat samples following sanitisation with different concentrations of C. caudatus extract (0.05, 0.50, and 5.00%) at different soaking times (5, 10, and 15 min). The sanitised samples were further evaluated with sensory acceptability (colour, odour, texture, and overall acceptability) to determine their acceptance level after treatment. Based on the results, the microflora in beef and shrimp meat samples were reduced significantly (p < 0.05) started from 0.05% at varied soaking times. The decrease in bacterial populations was proportional to the increase in extract concentrations and soaking times. In sensory acceptability, all cooked samples achieved acceptance level by the panellists at 0.05% after 10 min of soaking time. Food samples treated with 0.05% of C. caudatus extract and 10 min of soaking time showed the best combination in terms of bacterial reduction and the level of acceptance by the panellists. Hence, it can be concluded that C. caudatus extract has a high potential as a natural-based food sanitiser that can prevent bacterial contamination while maintaining the sensory acceptability of the foods. [ABSTRACT FROM AUTHOR]

In this work, polarization modulator utilizing MXene material, namely Nb2C is demonstrated. S band signal is injected into Nb2C thin film and is modulated by 1400 nm laser diode. A total of 39.81° of polarization rotation is attained when the pump power is increased to 223 mW. The rotation of light is due to thermo-optic effect. The efficiency of polarization modulator is calculated at 0.1974°/mW. [ABSTRACT FROM AUTHOR]

In this study, a mode-locked, Thulium-doped fiber (TDF) laser operating in the 2.0- $\mu \text{m}$ wavelength region and using an iron phosphorus trisulfide (FePS3) overlay with a polymer-coated on an arc-shaped fiber was successfully demonstrated. The mode-locked pulses were generated at a central wavelength of 1935.7 nm and a 3-dB bandwidth of 2.68 nm. Its soliton-like nature was validated by the presence of Kelly’s sidebands in the observed optical spectrum. The maximum repetition rate of the TDF mode-locked laser was 10.95 MHz, with a pulse width of 1.47 ps. The generated mode-locked output has significant stability, with no observable shifts in the central wavelength or Kelly’s sidebands over the measurement time due to the polymer’s protective layer. The experimental results show that a polymer-coated FePS3 arc-shaped fiber can be used as a SA device to produce stable and long-term mode-locked pulses in the TDF-based fiber laser. [ABSTRACT FROM AUTHOR]

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The dynamic bandwidth allocation (DBA) algorithm is highly impactful in improving the network performance of gigabit passive optical networks (GPON). However, reports delineating its vulnerability to certain attacks can be found in the literature, thus raising concerns. A degradation attack manipulates the transmission control protocol (TCP) congestion control algorithm, which may impact the received bandwidth of targeted network users. Here, the absence of electronics within the passive splitter renders attack identification in GPONs a significant challenge. Therefore, the current study aimed to propose a secured DBA mechanism known as security enhanced DBA capable of overcoming this particular threat. A detection phase served as a critical component for sensing and subsequently mitigating any abnormal behaviors observed among optical network units (ONUs). Upon identification of the attacker, penalties were imposed to deter the next attack attempt and reestablish the fairness to previously attacked ONUs. The simulation findings revealed throughput improvement of up to 63% due to the security feature offered by the mechanism. Besides, significant improvements for the upstream delay performance recorded at 52%, 60%, and 65% for traffic containers (TCONT) TCONT2, TCONT3, and TCONT4, respectively, were observed in comparison to the non-secure DBA mechanism. Hence, the integration of the security mechanisms in DBA renders it possible to avoid any exploitation of GPON vulnerability in hacking other users' bandwidth. [ABSTRACT FROM AUTHOR]

In this work, mode-locked thulium-doped fiber lasers operating in the 2 µm wavelength region were demonstrated using tantalum aluminum carbide (Ta2AlC)-based saturable absorbers (SAs) utilizing the evanescent wave interaction. The Ta2AlC MAX Phase was prepared by dissolving the Ta2AlC 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. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the effects of ageing simulation on the physical properties of Nano-Clay Modified Bitumens (NCMBs). Bitumen with the penetration grade of 60/70 is modified with 0, 2, and 4% nano-clay, and the consistency of the samples is characterized using the penetration, softening point, and viscosity tests before and after aging. Atomic Force Microscopy (AFM) was employed to evaluate the surface roughness and tip deflection of the modified bitumens. The results of the consistency tests revealed that incorporation of nano-clay up to 4% NC resulted in increased hardness of the modifed bitumen, and all the modifed bitumens were affected by ageing. Of note, the results from surface roughness and tip deflection showed a similar trend, while 2NCMB exhibited the lowest roughness and highest tip deflection. However, the results of the consistency tests and AFM conducted on ageing sensitivity of the bitumens were different, indicating that incorporation of nano-clay had an effect on the modified bitumen, but not on the unmodified bitumen. There was a high correlation between the results of consistency tests, surface roughness, and tip deflection, indicating that AFM could identify any changes in the fluidity of the bitumen. However, the correlation between the tip deflection and penetration was tenuous. [ABSTRACT FROM AUTHOR]

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 (Nb2C) was proposed and demonstrated as a saturable absorber to induce mode-locking in thulium- and thulium/holmium-doped fiber lasers. The Nb2C 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 Nb2C as a saturable absorber, offering opportunities to further explore MXenes for future photonics devices. [ABSTRACT FROM AUTHOR]

In this work, photon‐to‐photon polarization modulation is experimentally demonstrated using a Mxene material, Ti2C thin film as a modulator. S‐band signal (1500 nm) polarization state is modulated by a control pump (1400 nm) in the Ti2C thin film based on the thermo‐optic effect. A total of 34.67˚ of polarization rotation is achieved with the variation of pump power from 0 to 223 mW. From the regression analysis, the system is operated in highly linear condition, with R2 value of 0.991 and an efficiency of 0.1589˚/mW. Throughout the polarization rotational range, the variation of ellipticity is less than 5˚ while the variation of output power is less than 3.5 dB. [ABSTRACT FROM AUTHOR]

A MAX phase Ti3AlC2 thin film is demonstrated as a saturable absorber (SA) to induce Q-switching in the 2.0 μm region. The Ti3AlC2 thin film is sandwiched between two fiber ferrules and integrated into thulium doped fiber laser (TDFL) and thulium-holmium doped fiber laser (THDFL) cavities. Stable Q-switched pulses are observed at 1980.79 nm and 1959.3 nm in the TDFL and THDFL cavities respectively, with repetition rates of 32.57 kHz and 21.94 kHz and corresponding pulse widths of 2.72 μs and 3.9 μs for both cavities. The performance of the Ti3AlC2 based SA for Q-switching operation indicates the high potential of other MAX phase materials to serve as SAs in future photonics systems. [ABSTRACT FROM AUTHOR]

A tunable, passively Q-switched thulium doped fluoride fibre (TDFF) laser using a reduced-graphene oxide-silver (rGO-Ag) thin film as a saturable absorber (SA) for S band operation is proposed and its efficacy demonstrated. Over a pump power range of 91.4 mW up to 158.6 mW, passively generated Q-switched pulses are observed with repetition rates from 20 to 34.5 kHz and pulse widths from 3.1 to 7.1 µs. The highest pulse energy observed is 101.2 nJ with a signal to noise ratio of ∼42 dB. The proposed laser has a tuning range ∼52 nm from 1458 to 1510 nm with a tunable bandpass filter (TBPF) introduced into the cavity. [ABSTRACT FROM AUTHOR]