Dual Regime Mode-Locked and Q-Switched Erbium-Doped Fiber Laser by Employing Graphene Filament-Chitin Film-Based Passive Saturable Absorber.

We investigate the dynamics of high energy dual regime unidirectional Erbium-doped fiber laser in ring cavity, which is passively Q-switched and mode-locked through the use of an environmentally friendly graphene filament-chitin film-based saturable absorber. The graphene-chitin passive saturable absorber allows the option for different operating regimes of the laser by simple adjustment of the input pump power, yielding, simultaneously, highly stable and high energy Q-switched pulses at 82.08 nJ and 1.08 ps mode-locked pulses. The finding can have applications in a multitude of fields due to its versatility and the regime of operation that is on demand.

Simplified FE model and experimental study on the tensile properties of the glass fiber reinforced polyester polymer.

This research aims to understand the simplified finite element (FE) model behavior for estimating the glass fiber reinforced polyester polymer (GFRP) structural response and studying its tensile properties. The simplified FE model has been developed using an equivalent single-ply transversely isotropic material model to estimate the multi-layer GFRP laminates tensile behavior. The linear elastic and a trilinear plasticity material formulation were adopted. The experimental study is conducted to determine the tensile properties of the equivalent single-ply model of the multi-layer laminates with the variation of layers number, stacking sequence, and fiber orientation. The tensile test specimen used E-glass fiber reinforcement and polyester resin (Yukalac 157 BQTN-EX) as the matrix. The hand layup method was used for the lamination procedure. The experimental results show that the nonlinearity might occur due to the imperfection and poor quality of the composite laminate. Therefore, the comparison of numerical simulation and the experimental results is conducted to understand the stress-strain behavior of the simplified FE model. Both models presented different characteristics and showed good agreement with the experimental results. The linear model can be adopted while the nonlinearity is not significantly identified. Furthermore, the plastic strain as a compensated constant should be defined thoroughly to conduct an accurate estimation using the trilinear plasticity model. However, neither model is suitable for predicting the composite laminate's initial failure point.

Field-Dependent Rheological Properties of Magnetorheological Elastomer with Fountain-Like Particle Chain Alignment.

Magnetorheological elastomer (MRE) consists of magnetic particles known as carbonyl iron (CIPs), which have been locked in a silicone-based matrix, in various alignments. However, current MRE exhibits inadequate rheological properties due to several issues such as particle alignments. Therefore, in this study, a new approach of the particle alignment of CIPs in MRE, namely fountain-like structure, is introduced. It is expected that this kind of MRE exhibits enhancement rheological responses, in off- and on-state conditions. This work includes the development of a new mold that can produce various directions of magnetic flux lines in order to have fountain-like structures of CIPs in MRE, during the curing process. Three types of particle alignments in MRE, namely isotropic, fountain-like and inverted fountain-like, are fabricated. The rheological properties of MRE in terms of storage modulus and MR effect are measured in an oscillatory shear mode using a rheometer. The results have revealed that fountain-like MRE exhibits higher storage modulus than the isotropic MRE, approximately 0.6 MPa of increment in the strain sweep test, in an on-state condition. Furthermore, it has been demonstrated from strain, frequency and the current sweep test that the rheological properties of fountain-like MRE related to storage modulus and magnetorheological (MR) effect are higher compared to the inverted fountain-like MRE.

Comparison of Two Different Cut-Off Values of Scoring System for Diagnosis of Hirschsprung-Associated Enterocolitis After Transanal Endorectal Pull-Through.

Background: Hirschsprung-associated enterocolitis (HAEC) is a major contributor in the mortality of Hirschsprung disease (HSCR) patients that can occur both preoperatively and post-operatively. Several cut-off values of HAEC score have been used, i.e., ≥10 and ≥4. Here, we compared the HAEC frequency after transanal endorectal pull-through (TEPT) using two cut-offs of scoring system and associated them with the risk factors. Methods: Cross-sectional analysis was conducted using medical records of HSCR patients who were aged ≤18 years old and underwent TEPT at our institution, Indonesia between 2009 and 2016. HAEC was determined using the scoring system with cut-off values of ≥10 and ≥4. Results: Seventy subjects were used in the final analysis, consisting of 44 males and 26 females. There was a significant difference in one HAEC finding between the ≥10 and ≥4 cut-off groups; diarrhea with explosive stools (p = 0.002). The HAEC frequency was 5/70 (7.1%) and 49/70 (70%) patients using cut-off values of ≥10 and ≥4 (p < 0.0001), respectively. We found that patients with anemia (i.e., iron deficiency anemia) had a higher risk of HAEC after TEPT than patients with normal hemoglobin level with OR of 3.77 (95% CI = 1.28-11.1; p = 0.027), while no associations were found between other variables, including sex, age at diagnosis, age at definitive therapy, albumin level, and nutritional status and HAEC following TEPT (p = 0.87, 0.15, 0.33, 0.26, and 0.60, respectively). Also, no associations were observed between maternal education level, mother's age at pregnancy and gestational age and HAEC after definitive surgery (p = 0.10, 0.46, and 0.86, respectively). Conclusions: This report is the first study comparing two different cut-off values of scoring system to evaluate the HAEC frequency after TEPT and results suggest further using cut-off of ≥4 to expand the diagnosis of HAEC. Moreover, we also show for the first time that hemoglobin level is a strong risk factor for the HAEC development after TEPT.

Religious schema and tolerance towards alienated groups in Indonesia.

National discourses that are acceptable by the alienated groups determine the level of public tolerance towards those groups. This study thus examined the relationships between religious schema and tolerance of two alienated groups in Indonesia, namely, the atheists and believers in indigenous faiths. Additionally, the study explored the differences in tolerance of these two groups across university cohorts encompassing discrete social climates and curricula. This cross-sectional study involved several universities with differing demographic makeup. The analysis results revealed that the characteristics of the evaluated target group determined the significance of the associations between the dimensions of religious schema and tolerance. Moreover, students in homogeneous educational and social environments tended to exhibit low levels of tolerance towards alienated groups. This study highlighted the importance of scrutinising the functions of intergroup exposure and dialogues in improving intergroup understanding, acceptance, and tolerance within a plural society.

Analysis of Graphene Antenna Properties for 5G Applications.

The incoming 5G technology requires antennas with a greater capacity, wider wireless spectrum utilisation, high gain, and steer-ability. This is due to the cramped spectrum utilisation in the previous generation. As a matter of fact, conventional antennas are unable to serve the new frequency due to the limitations in fabrication and installation mainly for smaller sizes. The use of graphene material promises antennas with smaller sizes and thinner dimensions, yet capable of emitting higher frequencies. Hence, graphene antennas were studied at a frequency of 15 GHz in both single and array elements. The high-frequency antenna contributed to a large bandwidth and was excited by coplanar waveguide for easy fabrication on one surface via screen printing. The defected ground structure was applied in an array element to improve the radiation and increase the gain. The results showed that the printed, single element graphene antenna produced an impedance bandwidth, gain, and efficiency of 48.64%, 2.87 dBi, and 67.44%, respectively. Meanwhile, the array element produced slightly better efficiency (72.98%), approximately the same impedance bandwidth as the single element (48.98%), but higher gain (8.41 dBi). Moreover, it provided a beam width of 21.2° with scanning beam capability from 0° up to 39.05°. Thus, it was proved that graphene materials can be applied in 5G.

Enhancing Photocurrent Performance Based on Photoanode Thickness and Surface Plasmon Resonance Using Ag-TiO2 Nanocomposites in Dye-Sensitized Solar Cells.

This study investigated the different thicknesses of TiO2 photoanode films and the effect of surface plasmon resonance (SPR) of Ag-TiO2 nanocomposites on the current-voltage (I-V) performance of dye-sensitized solar cells (DSSC). The TiO2 layer was deposited using the doctor blade technique and the thickness of the TiO2 films was controlled by using a different number of Scotch tape layers. The silver nanoparticles (AgNP) were synthesised using a chemical reduction method and the concentration of sodium citrate as a reducing agent was varied from 4 to 12 mM to study the effect of citrate ion on the size of the nanoparticles. Ag-TiO2 nanopowder was prepared by adding pure anatase TiO2 powder into AgNP colloidal solution. The mixture was left to dry for 24 h to obtain Ag-TiO2 powder for paste preparation. The three-layer Scotch tape, with thickness of 14.38 µm, achieved a high efficiency of 4.14%. This results showed that three layers was the optimal thickness to improve dye loading and to reduce the charge recombination rate. As for the Ag-TiO2 nanocomposites, 10 mM of AgNP, with a mean diameter of 65.23 nm and high efficiency of 6.92%, proved that SPR can enhance the absorption capability of dye and improve the photon-to-electron generation.

Androgen correlates of male reproductive effort in wild male long-tailed macaques (Macaca fascicularis): A multi-level test of the challenge hypothesis.

The challenge hypothesis (Wingfield et al., 1990) has been broadly utilised as a conceptual framework to study male androgen correlates of reproductive challenges in mammals. These studies mainly assessed male androgen responsiveness to a general degree of challenge over extended periods of time. Short term co-variation between the socio-sexual challenging context and androgen levels remains, however, largely understudied. We thus aim at providing a multi-level test of the challenge hypothesis by investigating the inter- and intra-individual variations in faecal androgen excretion associated to 1) breeding seasonality, 2) dominance rank, 3) mate-guarding activity and 4) value of the guarded female. We studied long-tailed macaques, a species in which males engage in highly challenging monopolisation of females over discreet periods of time. This particularity allows testing specifically the predicted increase from level B to level C in the challenge hypothesis. The study was carried out during two reproductive seasons on three groups of wild long-tailed macaques. We combined behavioural observations and non-invasive measurements of faecal androgen metabolite (fAM) levels. We found that, as predicted by the challenge hypothesis, male long-tailed macaques respond not only to seasonal but also to short term reproductive challenges by adapting their androgen levels. First, males exhibited a seasonal rise in fAM levels during the mating period which may be triggered by fruit availability as shown by our phenological data. Second, males had increased androgen levels when mate-guarding females and, across mate-guarding periods, males had higher fAM levels when monopolising high-ranking parous females than when monopolising low-ranking ones. Finally, high-ranking males had higher fAM levels than low-ranking males year round. Our study confirms that, in species with a high degree of female monopolisability, androgen may be an important physiological fitness enhancing tool for males by increasing female monopolisation efficiency (in particular with highly valuable females) and helping males to respond to rank take-over challenges.

Nanosecond soliton pulse generation by mode-locked erbium-doped fiber laser using single-walled carbon-nanotube-based saturable absorber.

We demonstrate a simple and low cost mode-locked erbium-doped fiber laser (EDFL) operating in the nanosecond region using a single-walled carbon nanotube (SWCNT)-based saturable absorber (SA). A droplet of SWCNT solution is applied on the end of a fiber ferrule, which is then mated to another clean connector ferrule to construct an SA. Then the SA is integrated into a ring EDFL cavity for nanosecond pulse generation. The EDFL operates at around 1570.4 nm, with a soliton-like spectrum with small Kelly sidebands, which confirms the attainment of the anomalous dispersion. It produces a soliton pulse train with a 332 ns width, repetition rate of 909.1 kHz, an average output power of 0.31 mW, and energy of 0.34 nJ at the maximum pump power of 130.8 mW.