Quality Factor Research Articles

Design and performance evaluation of a 350 m free space optical communications link for pico-macrocell backhauling

Fibreless optics or free space optical communications (FSOC) has been at the forefront of many academic research in telecommunications due to its numerous benefits of large spectrum, high-speed data transmission, security, low transmit power, unlicensed spectrum and non-interfering links. Among the technical challenges of dense deployment of small cells in heterogeneous networks (HetNet) is a flexible and cost-effective backhaul link. This paper proposes, designs, simulates and evaluates the performance of a 350 m FSOC link under different atmospheric impairments for picocell to macrocell backhauling applications. The performance of the FSOC link is assessed by evaluating bit error rate (BER), eye diagram and quality factor (Q-factor). Results obtained recommend the FSOC link deployment for pico-macrocell backhauling under the weather conditions of clear sky with/without turbulence, heavy rain, heavy haze, heavy fog and wet snow.

Performance of machine learning models to forecast PM10 levels

Machine learning techniques have garnered considerable attention in modern technologies due to their promising outcomes across various domains. This paper presents the comprehensive methodology of an optimized and efficient forecasting approach for Particulate Matter 10, specifically tailored to predefined locations. The execution of a comparative analysis involving eight models enables the identification of the most suitable model that aligns with the primary research objective. Notably, the test results underscore the superior performance of an ensemble model, which integrates state-of-the-art methodologies, surpassing the performance of the other seven state-of-the-art models. Adopting a case-specific methodology with machine learning techniques contributes to achieving a notably high regression coefficient (R²≈1) across all models. Furthermore, the study underscores the potential for future endeavors in predicting location-specific environmental factors.•This study focused on forecasting PM10 with machine learning models with the consideration of air quality factors and meteorological factors•Ensemble model was developed for the forecasting purposes with higher performance.

Factor analysis influencing Mobile JKN user experience using sentiment analysis

<span lang="EN-US">Social security administration for health or Badan Penyelenggara Jaminan Sosial Kesehatan (BPJS Kesehatan), as a public legal entity, has a critical role in the health of the Indonesian population. BPJS Kesehatan introduced the Mobile national health insurance or </span><em><span lang="EN-US">jaminan kesehatan nasional</span></em><span lang="EN-US"> (JKN) application to enhance its services, enabling Indonesians to access it directly. Nevertheless, the rating of the Mobile JKN application on the Google Play Store has shown a gradual decline over time. Therefore, this study was conducted to analyze the factors influencing the user experience of the Mobile JKN application, utilizing the review data obtained from the Google Play Store. Sentiment analysis using the Naïve Bayes (NB) classification model and support vector machine (SVM) combined with synthetic minority oversampling technique (SMOTE) and slang word replacement. The results obtained an accuracy value of 93.33%, precision of 93.76%, recall of 93.33%, and F1-score of 93.43%. A further analysis was conducted using online service quality factors to obtain the main factors influencing the experience of Mobile JKN application users. The evaluation findings revealed that factors of security, ease of use, and timeliness are three fundamental aspects that should be given immediate attention by BPJS Kesehatan while improving the Mobile JKN application in the future.</span>

Examining Citizens’ Expectations and Perceptions About Service Quality in Public Sector: Adapting a Hybrid Public Service Quality Model to the Local Context

ABSTRACT The empirical study examines citizens’ expectations and perceptions about service quality in three major public institutions. The article adopts a quantitative approach. Citizens’ expectations and perceptions about service quality in the context of public institutions were examined through a questionnaire, utilizing a hybrid model of SERVQUAL with private and public service quality dimensions. The article presents the results of a quantitative study (sample of 310 citizens), distributed across three public institutions, illustrating factor, gap, paired correlation and one-way analysis of variance (ANOVA) of survey data. For factor extraction, rotation and interpretation, the Oblimin rotation technique was used, determining inter-correlation among the public service quality factors. As for ANOVA analysis, Levene’s test was used to verify the homogeneity of variance assumption (the variance in scores for each group of customers). The findings of the study suggest the re-distribution of components under the refined service quality factors. Different items of initial service quality dimensions are rotated under newly created factors. Gap analysis reveals no variations in terms of citizens’ expectations across public institutions, but suggests significant differences among public entities in regard to perceptions of services acquired. Adapted Hybrid Public Service Quality model will assist public institutions in developing and tailoring service quality management systems to citizens’ needs. This is the first attempt to carry out a quantitative approach to researching Service Quality in public institutions. The primary contribution of the study is that it has tested a hybrid model for measuring perceived public service quality, integrating service quality dimensions both from public and private sectors and proposed a refined model fit for the local context considering citizens’ characteristics and the current state of the public sector experiencing a shift toward modernization of services.

Chromosomal damage, gene expression and alternative transcription in human lymphocytes exposed to mixed ionizing radiation as encountered in space

Astronauts travelling in space will be exposed to mixed beams of particle radiation and photons. Exposure limits that correspond to defined cancer risk are calculated by multiplying absorbed doses by a radiation-type specific quality factor that reflects the biological effectiveness of the particle without considering possible interaction with photons. We have shown previously that alpha radiation and X-rays may interact resulting in synergistic DNA damage responses in human peripheral blood lymphocytes but the level of intra-individual variability was high. In order to assess the variability and validate the synergism, blood from two male donors was drawn at 9 time points during 3 seasons of the year and exposed to 0–2 Gy of X-rays, alpha particles or 1:1 mixture of both (half the dose each). DNA damage response was quantified by chromosomal aberrations and by mRNA levels of 3 radiation-responsive genes FDXR, CDKN1A and MDM2 measured 24 h post exposure. The quality of response in terms of differential expression of alternative transcripts was assessed by using two primer pairs per gene. A consistently higher than expected effect of mixed beams was found in both donors for chromosomal aberrations and gene expression with some seasonal variability for the latter. No synergy was detected for alternative transcription.

Demonstration of 4H-silicon carbide on an aluminum nitride integrated photonic platform

The existing silicon-carbide-on-insulator photonic platform utilizes a thin layer of silicon dioxide under silicon carbide (SiC) to provide optical confinement and mode isolation. Here, we replace the underneath silicon dioxide layer with 1-µm-thick aluminum nitride and demonstrate a 4H-silicon-carbide-on-aluminum-nitride integrated photonic platform for the first time to our knowledge. Efficient grating couplers, low-loss waveguides, and compact microring resonators with intrinsic quality factors up to 210,000 are fabricated. In addition, by undercutting the aluminum nitride layer, the intrinsic quality factor of the silicon carbide microring is improved by nearly one order of magnitude (1.8 million). Finally, an optical pump–probe method is developed to measure the thermal conductivity of the aluminum nitride layer, which is estimated to be over 30 times of that of silicon dioxide.

The preparation and magnetic properties of FeSiCr/MoS2 soft magnetic composites

Abstract Two-dimensional layered material MoS2 was used as a high-resistance insulating material and coated on FeSiCr magnetic powder, and FeSiCr/MoS2 composites with low loss and high permeability were successfully prepared. The morphology and magnetic properties of FeSiCr/MoS2 composites were analyzed by XRD, SEM and B-H analyzer. The results show that although the addition of MoS2 will dilute the magnetic properties of FeSiCr, it still has high permeability and obviously reduces the magnetic loss of FeSiCr powder. At the same time, the addition of MoS2 also improves the frequency stability and quality factor of the composite powder cores. Especially, when the MoS2 content is 1.5 wt%, FeSiCr/MoS2 composites show the best magnetic properties after annealing at 500 ℃. with a loss of 330 mW/cm3 and permeability of 66.75 (Bm =20 mT and f =1000 kHz). It can be seen that the MoS2 coating has a good effect on reducing the magnetic loss of powder core, which significantly improves the possibility of application of SMCs at high frequency.

Optimal sizing and siting of single tunned passive filter based on jellyfish algorithm

<p class="MsoNormal" style="margin-top: 10pt; text-align: justify;"><span lang="EN-US" style="font-family: 'times new roman', times, serif; font-size: 14pt;">The presence of electrical harmonics in low voltage networks causes many problems for customers, the most important of which is the decrease in the power quality beyond the permissible limits, which leads to a decrease in voltage for long periods, a decrease in power factor and a large losses in the electrical network due to the deformation of the electric waveform of voltage and current. The aim of this paper is to design an optimal passive filter and its optimal location to suppress the harmonic distortion in the distribution system that results from nonlinear loads. This filter will use single objective functions and multi objective functions that will minimize the proposed filter cost, the real power losses, total harmonic distortion "THD" and individual harmonic distortion "IHD". This will be done under the equality constraint of power balance and some inequality constraints such as filter parameters limits, quality factor limits, voltage limits, harmonic distortion limits. The optimal passive filter parameters and location will be calculated using the modern optimization techniques such jellyfish optimization technique. IEEE 33 bus radial system will be used for demonstrating results obtained by the proposed method.</span></p>

Temperature dependence of microwave losses in lumped-element resonators made from superconducting nanowires with high kinetic inductance

Abstract We study the response of several microwave resonators made from superconducting NbTiN thin-film meandering nanowires with large kinetic inductance, having different circuit topology and coupling to the transmission line. Reflection measurements reveal the parameters of the circuit and analysis of their temperature dependence in the range 1.7-6 K extract the superconducting energy gap and critical temperature. The lumped-element LC resonator, valid in our frequency range of interest, allows us to predict the quasiparticle contribution to internal loss, independent of circuit topology and characteristic impedance. Our analysis shows that the internal quality factor is limited not by thermal-equilibrium quasiparticles, but an additional temperature-dependent source of internal microwave loss.

Centimeter-scale nanomechanical resonators with low dissipation

High-aspect-ratio mechanical resonators are pivotal in precision sensing, from macroscopic gravitational wave detectors to nanoscale acoustics. However, fabrication challenges and high computational costs have limited the length-to-thickness ratio of these devices, leaving a largely unexplored regime in nano-engineering. We present nanomechanical resonators that extend centimeters in length yet retain nanometer thickness. We explore this expanded design space using an optimization approach which judiciously employs fast millimeter-scale simulations to steer the more computationally intensive centimeter-scale design optimization. By employing delicate nanofabrication techniques, our approach ensures high-yield realization, experimentally confirming room-temperature quality factors close to theoretical predictions. The synergy between nanofabrication, design optimization guided by machine learning, and precision engineering opens a solid-state path to room-temperature quality factors approaching 10 billion at kilohertz mechanical frequencies – comparable to the performance of leading cryogenic resonators and levitated nanospheres, even under significantly less stringent temperature and vacuum conditions.

Improving Output Power of a Torsional-Flutter Harvester in Stochastic Thunderstorms by Duffing - Van Der Pol Restoring Torque

Abstract Wind energy harvesters are usually designed to operate in the low wind speed range. They rely on smaller swept areas, as a complement to larger horizontal-axis wind turbines. A torsional-flutter-based apparatus is investigated herein to extract wind energy. A nonlinear hybrid restoring toque mechanism, installed at equally spaced supports, is used to produce energy through limit-cycle vibration. Energy conversion and storage from the wind flow are enabled by eddy currents. The apparatus is used during thunderstorm outflows to explore the efficiency in non-ideal wind conditions. The thunderstorm flow model accounts for both non-stationary turbulence and slowly varying mean speed, replicating thunderstorm's intensification and decay stages. This paper evolves from a recent study to examine stochastic stability. More Specifically, the output power is a random process that is derived numerically. Various thunderstorm features and variable apparatus configurations are evaluated. Numerical investigations confirm the detrimental effect of non-ideal, thunderstorms on harvester performance with, on average, an adverse increment of operational speed (about +30\%). Besides nonlinear damping, the benign flutter-prone effect is controlled by the square of the flapping angle. Since flapping amplitudes are moderate at sustained flutter, activation of the apparatus is delayed and exacerbated by the non-stationary outflow and aeroelastic load features. Finally, efficiency is carefully investigated by quantification of output power and “quality factor”.

Enhanced Photon-Pair Generation Based on Thin-Film Lithium Niobate Doubly Resonant Photonic Crystal Cavity

In this work, a doubly resonant photonic crystal (PhC) cavity is proposed to enhance second harmonic generation (SHG) efficiency and photon pair generation rate (PGR). Through the exploration of geometry parameters, a band-edge mode within the light cone is identified as the first harmonic (FH) mode, and a band-edge mode outside the light cone is designated as the second harmonic (SH). Subsequently, by increasing the layers of the core region, a heterostructure PhC cavity is designed. The results showcase a doubly resonant PhC cavity achieving a 133/W SHG efficiency and a photon pair generation rate of 3.7 × 108/s. The exceptional conversion efficiency is attributed to the high quality factors Q observed in the FH and SH modes with values of approximately 280,000 and 2100, respectively. The remarkably high Q factors compensate for nonlinear efficiency degradation caused by detuning, simultaneously making the manufacturing process easier and more feasible. This work is anticipated to provide valuable insights into efficient nonlinear conversion and photon pair generation rates.

Band flipping and bandgap closing in a photonic crystal ring and its applications

The size of the bandgap in a photonic crystal ring is typically intuitively considered to monotonically grow as the modulation amplitude of the grating increases, causing increasingly large frequency splittings between the "dielectric" and "air" bands. In contrast, here we report that as the modulation amplitude in a photonic crystal ring increases, the bandgap does not simply increase monotonically. Instead, after the initial increase, the bandgap closes and then reopens again with the two bands flipped in energy. The air and dielectric band edges are degenerate at the bandgap closing point. We demonstrate this behavior experimentally in silicon nitride photonic crystal microrings, where we show that the bandgap is closed to within the linewidth of the optical cavity mode, whose intrinsic quality factor remains unperturbed with a value ≈ 1×106. Moreover, through finite-element simulations, we show that such bandgap closing and band flipping phenomena exist in a variety of photonic crystal rings with varying unit cell geometries and cladding layers. At the bandgap closing point, the two standing wave modes with a degenerate frequency are particularly promising for single-frequency lasing applications. Along this line, we propose a compact self-injection locking scheme that integrates many core functionalities in one photonic crystal ring. Additionally, the single-frequency lasing might be applicable to distributed-feedback (DFB) lasers to increase their manufacturing yield.

5 kW power-level 1050 nm narrow-linewidth fiber amplifier enabled by biconical-tapered active fiber

Effective wavelength extension is vital in the applications of high-power narrow-linewidth fiber lasers. In this work, we demonstrate a 5-kW power-level narrow-linewidth fiber amplifier at 1050 nm utilizing a homemade biconical-tapered Yb-doped fiber (BT-YDF). Up to ∼4.96 kW fiber laser is achieved with a 3 dB linewidth of ∼0.54 nm and a beam quality factor of Mx2 = 1.46, My2 = 1.6. The experimental comparisons reveal that BT-YDF has the advantages of improving a stimulated Raman scattering threshold and balancing transverse mode instability suppression in the fiber amplifier. This work could provide a good reference for extending the operating wavelength of high-power fiber amplifiers.

Bringing source text quality into the legal translation classroom: training translators to face defective source texts

ABSTRACT Legal translators are routinely faced with defective source texts in their professional practice while being expected to produce effective translations despite such quality issues. Given the high-quality expectations required in legal translation, we have brought this professional reality into the classroom by outlining a quality control activity to allow legal translation trainees to systematise how they deal with defective Spanish administrative source texts. The proposal includes two steps: a translatability assessment and a pre-editing stage of defective administrative source texts. After empirically testing our proposal in the classroom, our initial findings suggest that this approach not only assists trainees to factor in poor source text quality when translating, but also to produce better translations.

Development and Acceptability of Web-based Module in Cookery

This study delves into the development and acceptance of a web-based cookery module, aiming to enhance culinary education, particularly in the face of challenges such as the pandemic. These modules offer promising avenues for effective learning experiences and the promotion of self-regulated learning among students. Employing a mixed-method approach utilizing the Input-Process-Output design model, the study involves the validation of the developed module by eight expert practitioners in cookery. Subsequently, its acceptability will be assessed among Senior High School (SHS) Technical-Vocational-Livelihood (TVL) students enrolled in cookery subjects during the academic year 2023-2024. Evaluation of the module by teacher experts utilizes a four-point rating scale, drawing from the Guidelines and Processes for Learning Resource Management and Development System (LRMDS) Assessment & Evaluation – Evaluation Rating Sheet for Non-Print Materials (DepEd, 2009), focusing on content quality, instructional quality, technical quality, and other pertinent factors. Similarly, student feedback is gathered through a five-point scale adapted from Venkatesh et al. (2003) and modified by Namoco, S. (2021) to align with the Unified Theory of Acceptance and Use of Technology (UTAUT) model, offering both rating scale responses and descriptive interpretations. Both teacher experts and student users are purposefully selected for their insights. Initial findings from the expert evaluation indicate a high recommendation for implementing the web-based module in cookery education. However, ongoing data collection and analysis are underway to gauge student-user acceptability comprehensively. This study underscores the significance of well-designed interactive learning modules in fostering self-regulated learning and enhancing student performance in cookery subjects, notwithstanding the challenges posed by the pandemic and economic constraints.

Culture Medium as a Decisive Factor for Embryo Quality

Culture Medium as a Decisive Factor for Embryo Quality

Influence of sleep quality and other associated factors on glycemic control among diabetic patients: A hospital-based study

The glycemic control of diabetes patients is influenced by a variety of risk factors, some of which are adjustable and others of which are not. Diabetes and sleep quality are most frequently correlated in both directions. To evaluate the quality of sleep and pinpoint the risk factors for inadequate glycemic control in individuals with diabetes. : This cross-sectional study included seventy consecutive patients who met the inclusion criteria. The Pittsburgh Sleep Quality Index (PSQI) scale was used to evaluate the quality of sleep. Siemens- ID 29984, dimension RxL Max, Architect plus ABBOT (ci 4100), completely automatic seven-part cell-counter by Horiba Pentra Dx and Siemens ADVIA Centaur XPT (Immonoassay system) were utilized for the biochemical tests.: Of the 70 participants in the study, 22 patients [31.4%] reported having good sleep quality, while 15 patients [21.4%] had average sleep quality and 33 patients [47.1%] had poor sleep quality. Patients with managed and uncontrolled blood sugar showed varying degrees of sleep quality; 48.4% and 17.9% showed good sleep quality, 29% and 15.4% showed moderate sleep quality, and 22.6% and 66.7% showed poor sleep quality. A statistically significant difference (p<0.001) was seen in the sleep quality of the two groups. : In summary, the results of our study suggested that diabetics with poor sleep quality are more likely to have poor glycemic control. A significant modifiable risk factor for improved glycemic management in diabetic patients is sleep quality.

Directly modulated deformed-square-FP coupled-cavity laser with intracavity-mode photon-photon resonance

We propose and demonstrate a high-speed directly modulated laser based on a hybrid deformed-square-FP coupled cavity (DFC), aiming for a compact-size low-cost light source in next-generation optical communication systems. The deformed square microcavity is directly connected to the FP cavity and utilized as a wavelength-sensitive reflector with a comb-like and narrow-peak reflection spectrum for selecting the lasing mode, which can greatly improve the single-mode yield of the laser and the quality (Q) factor of the coupled mode. By optimizing the device design and operating condition, the modulation bandwidth of the DFC laser can be enhanced due to the intracavity-mode photon-photon resonance effect. Our experimental results show an enhancement of 3-dB modulation bandwidth from 19.3 GHz to 30 GHz and a clear eye diagram at a modulation rate of 25 Gbps.

Thermodynamic modeling and performance analysis of photovoltaic-thermal collectors integrated with phase change materials: Comprehensive energy and exergy analysis

Phase change materials (PCMs) integrated with photovoltaic-thermal (PVT) collectors can simultaneously generate and store electrical and thermal energy. However, design optimization requires accurate modeling of the complex heat transfer processes in PCMs under varying operating conditions. This study introduces an efficient simulation approach with generalized Nusselt number correlations to enable precise and rapid analysis of PCM thermal performance. A numerical model is developed to quantify heat fluxes, node temperatures, energy and exergy outputs across PCM solid, melting, and liquid states. Extensive analysis is conducted to explore the impact of irradiation, ambient temperature, PCM thickness, tilt angle, and wind speed on PVT performance. Key findings include: (1) thermal energy yield exceeds electrical output by 2.8 times owing to PV's low efficiency, while electrical exergy dominates thermal exergy by 5.3 times highlighting electric output's primacy; (2) electrical output chiefly depends on irradiation, while thermal energy and exergy are highly sensitive to ambient temperature and wind speed; (3) thermal energy escalates 4.5 times faster than electrical energy with irradiation rise, but thermal exergy drops sharply from 10.1 to 0.34 W as ambient temperature increases from 0 to 35 °C due to quality factor degradation. The study provides new generalized correlations, validated model, and extensive performance assessment to advance PCM-based PVT collector design.