Loop Frequency Research Articles

Association between dermatoglyphics and dental caries among children aged 6 to 12 years old

Background: There is a relationship between dermatoglyphic patterns and oral diseases. This study aimed to compare the rate of dermatoglyphic patterns between the caries-active group and the caries-free group. Method: The study was performed on 371 children aged 6 - 12 years at Khe Tre Town primary school, Nam Dong district, Thua Thien Hue province. The children were examined and assessed for the decayed, missing, and filled teeth index. The fingerprints of both the caries-active group and the caries-free group were recorded and then classified and compared between the two groups. Results: The frequency of whorls was found to be more in the caries-active group and the frequency of loops was more in the caries-free group. Conclusion: Dermatoglyphic patterns may be used as a non-invasive tool for screening of early dental caries and guiding future research Key words: dermatoglyphics; the decayed, missing, and filled teeth index; dental caries.

A high dynamic carrier acquisition and tracking algorithm for space coherent optical communication

In coherent optical communication, the Doppler frequency offset reaches several GHz, which seriously affects the performance of the coherent demodulation system and increases the bit error rate. In this paper, a novel carrier acquisition and tracking algorithm for spatial coherent optical communication is proposed. The algorithm adopts the dual-locked frequency loop that the CPAFC tracking algorithm is effectively combined with the ODAFC tracking algorithm. The CPAFC tracking algorithm can be used for frequency offset gradually change capture and tracking, and the ODAFC tracking algorithm can capture large frequency offset, and according to the locked state control the working state of the two FLL loops. In the condition of stable locked, use only the CPAFC tracking algorithm to capture the gradually changing frequency offset; in the other condition, use two FLL loops together. The experimental results show that the 5Gbps BPSK laser communication performance loss is less than 1.5 dB when the Doppler frequency offset is 2.5 GHz, and the carrier frequency offset change rate is 20 MHz/s.

Identification of obesity in children and teenagers.

Obesity is a condition that increases the risk of developing several health problems, resulting in high health care costs worldwide. Therefore, it is important to investigate several avenues for the control of this condition. This study aimed to identify a dermatoglyphical condition that distinguishes obesity individuals from those of appropriate weight. The sample comprised 2172 children and teenagers between the ages of 10 and 19 years, female and male, from public and private schools of the municipality of Joaçaba, Santa Catarina, Brazil. In a comparison of qualitative variables, i.e., patterns, significant differences were observed between groups, including a higher frequency of ulnar loops (LU) on the index and middle fingers (MET2 and MET3) in the appropriate weight group. In the obesity group, a greater frequency of whorls (W) on fingers MET2 and MET3 was observed in males. In females, there were statistically significant correlations between the presence of radial loops (LR) on MET3 in the appropriate weight group and arches (A) in the obesity group. The study uncovered dermatoglyphical marks characteristic of obesity individuals.

Oxygen diffusion impedance in proton exchange membrane fuel cells – insights into electrochemical impedance spectra and equivalent electrical circuit modeling

In Randles circuit, the oxygen diffusion impedance connects in series with the Oxygen Reduction Reaction charge-transfer resistance, implying that the Cathode Catalyst Layer (CCL) governs oxygen diffusion. The oxygen diffusion impedance can be connected in series with the ORR circuit, implying that Gas Diffusion Layer (GDL) rules oxygen diffusion. The common finite Warburg element and an alternative expression for diffusion through GDL derived by Kulikovsky were tested and compared. For this, experimental data obtained from measurements on various cells geometries, MEA types and operating conditions were used. All cases yield the same trend: the low frequency diffusion impedance in PEMFC mainly relates to the GDL, or both the GDL and the CCL, the latter to a significantly lower extent. EI spectra measured for different cathode Pt-loadings suggest that the ionomer film inside the CCL contributes rather to the high-frequency resistance, increasingly at lower catalyst loading. Hence, the physically most appropriate equivalent electrical circuit is a Kulikovsky diffusion impedance connected in series with the ORR kinetics circuit. Comparing global and local impedance spectra confirmed the significant contribution of perturbation-induced oxygen concentration oscillations to the low frequency loop in Nyquist plots: analyzing local impedance data measured near the oxygen inlet allows to minimize their impact.

Fingerprint patterns in relation to an altered neurodevelopment in patients with autism spectrum disorder

AbstractDermatoglyphic patterns are permanently established and matured before the 24th week of gestation. Their frequencies and localization might be a good indicator of developmental instability in individuals with an altered neurodevelopment and show potential as biomarkers of autism spectrum disorder (ASD). In this study, fingerprint pattern counts and fluctuating asymmetry in the distribution of patterns are compared between 67 boys diagnosed with ASD (aged 5.11 ± 2.51 years) and 83 control boys (aged 8.58 ± 3.14 years). Boys with ASD had a higher rate of discordance in their fingerprint patterns (p = .0026), showing more often bilateral differences in the occurrence of certain patterns. A chi‐square test revealed that the difference in pattern frequencies between boys with ASD and the control group is the most significant in frequencies of whorls, tented arches, and ulnar loops. Boys with ASD have significantly fewer ulnar loops, significantly more whorls, and tented arches in the right hand. The achieved results are in favor of the suggestion that prenatal influences, which play a role in the development of bilateral differences in fingerprint patterns up to the 24th week of gestation, may be a potential cause of an altered neurodevelopment in ASD individuals.

Modeling and Control of a 5-DOF Parallel Continuum Haptic Device

In this article, we propose a new continuum robotics approach for haptic rendering and comanipulation. This approach is illustrated using a robotic interface with six motorized fixed axes connected by deformable beams, in parallel, to an end effector with 5 degrees of freedom. Apart from the rotation of the motors, this design has no articulation, and the motion of the end effector is achieved by deformation of the beams. The flexible beams are equipped with bending sensors, and the motors have encoders. We use a nonlinear finite element mechanical model of the robot based on a mesh of beam elements that is computed in real time at 20 Hz. The bending sensors are incorporated into the model, which allows us to obtain an accurate estimate of the force exerted by the user on the end effector. The model enables a new methodology for calculating the workspace of the continuum haptic device. The model also is propagated to a higher frequency loop (500 Hz), which performs sensing and control of the robot at high rates, using an admittance-type control to command new positions of the actuators. We show that this control methodology allows haptic rendering of virtual walls that are stiffer than the natural stiffness of the robot. Finally, we demonstrate the use of the device for simple comanipulation tasks.

Voltage unbalance and inertia based frequency control framework considering intelligent load management for stand-alone operation of microgrid

The less inertial microgrid with high penetration of Renewable Energy Sources (RES) faces several issues including voltage and frequency unbalance. The intermittent nature of RES-based Distributed Generations (DGs) makes the system unstable in the absence of a control mechanism in a stand-alone microgrid. The integration of single-phase loads and sudden load switching on the distribution side make the system prone to several malicious events. The unbalance in voltage among the phases and the high Rate of Change of Frequency (RoCoF) are the major concern for degrading the system’s performance during peak and off-peak hours. The paper addresses a hierarchical dual loop voltage and frequency control mechanism where the primary control is equipped with droop strategy and Positive-Negative Sequence Control (PNSC) to maintain Voltage Unbalance Factor (VUF) and adhere to IEC-61000-3-13. Further, the inertial loop is also implemented to mitigate frequency deviation and reduce transient overshoot. The secondary control mechanism enables intelligent load management by scheduling Thermostatic Control Loads (TCLs) during peak hours. The utmost care is taken for the Customer’s Thermal Comfort (CTC) while scheduling the loads. The rigorous simulation is done in MATLAB Simulink and Digsilent Power Factory with a modified IEEE 13 bus system considering system dynamics. Further, the real-time simulation is also performed with OPAL-RT to validate the efficacy of the above methodology.

Synchronizing Control of Wind Turbine Driven Doubly Fed Induction Generator System With DG in Remote Area Involving Solar PV-Battery Energy Storage

This paper presents a synchronizing control for wind turbine (WT) driven doubly fed induction generator (DFIG) system with DG (Diesel Generator) in a remote area consisting of solar photovoltaic (PV) array and the battery energy storage. The DFIG is operated with two voltage source converters (VSCs) namely VSC on rotor side (VSCR) and VSC on load side (VSCL) by sharing common DC link with a battery. Moreover, the solar PV array is connected to the DC link through a boost converter, which is used to acquire peak power from the PV array. The microgrid is designed with minimum power converters with enhanced reliability and reduced intermittency especially for islands. Moreover, two controls are presented for successful and smooth operation of microgrid. An additional frequency loop is added in the control of VSCR for minimizing the power fluctuations and for smooth connection of DG to DFIG-solar-battery based isolated microgrid with static transfer switch. Moreover, the VSCR control is framed to build the rated voltage at the DFIG stator with control over ON/OFF operation of VSCR. It is also designed to harness the maximum power from wind. The control of VSCL is framed to regulate the DG power to operate it in optimal fuel consumption zone whenever it is synchronized. Simulations are performed at steady and varying wind speeds, varying PV insolation and at unbalanced connected loads. Moreover, a prototype of isolated microgrid is developed in the laboratory and its experimental performance is investigated at different operating scenarios to evidence its robustness.

Dermatoglyphics: Prediction for Prevention: An Innovative Tool in our Stash!

Early childhood caries (ECC) has created pandemonium worldwide and so in India which is alarming and accentuates the need to foster novel and effective preventive strategies that are synergistic with the current one. There are different methods to diagnose ECC. Nonetheless, up until now, there has been no method to predict ECC. Dermatoglyphics could be considered a noninvasive and early predictor of dental caries in children, as ECC is a multifactorial disease with the influence of genetic patterns. The present study was undertaken to find out a possible relation between some quantitative and qualitative dermatoglyphic variables, ECC, and salivary bacteria. The study was carried out on 200 children within the age-group of 36-72 months. The study population was divided into four groups comprising 50 individuals each based on decayed, missing and filled teeth (dmft) score and gender; group I-caries male (dmft ≥ 5), group II-caries free male (dmft score 0), group III-caries female (dmft≥ 5), and group IV-caries free female (dmft score 0). Dermatoglyphic patterns of all 10 palmar digits were recorded and assessed qualitatively and quantitatively. The caries group showed maximum occurrence of whorls, which were more prevalent in females and decreased frequency of loops when compared to caries free group. There was a significant association of the whorl pattern with the microbial counts of Streptococcus mutans (S. mutans) and Lactobacillus. There is explicit variation in dermatoglyphic patterns between the ECC and caries-free group indicating a correlation between dermatoglyphic patterns and dental caries. Shah SG, Kaul B, Gupta A, et al. Dermatoglyphics: Prediction for Prevention: An Innovative Tool in our Stash! Int J Clin Pediatr Dent 2023;16(S-1):S101-S108.

Highly sensitive torsion sensor based on a coupled optoelectronic oscillator incorporating nonlinear polarization rotation.

We propose and demonstrate a new, to the best of our knowledge, technique to implement a high-speed and highly sensitive torsion sensor based on a coupled optoelectronic oscillator (COEO) incorporating nonlinear polarization rotation (NPR). The COEO consists of a mode-locked laser loop and an OEO loop. In the laser loop, the NPR effect effectively induces intensity- and wavelength-dependent loss, which acts as a Lyot birefringent fiber filter. When twisting the polarization-maintaining fiber (PMF), the transmission of the filter varies as well as the laser output wavelength. In the OEO loop, the optical source is provided by the output signal of the mode-locked laser. The variation in the optical carrier wavelength changes the time delay and the oscillation frequency of the OEO loop. The oscillation frequency shift is a linear function of the twist angle. Sensitivities of -60.006 Hz/deg over 360° for a 48 cm PMF and -180.996 Hz/deg over 92° for a 22 cm PMF are achieved.

Performance investigation and control design of SSI grid-connected system for PV applications with maximum power extraction

Split-source inverter (SSI) has been recently developed as an alternative to the commonly used ZSI where it can serve an interface between the renewable energy sources and the common grid. This paper presents a mathematical model and control strategy for grid-connected SSI system with either constant voltage source or photovoltaic (PV) source. The control strategy is based on linear PI controllers which are fine-tuned by the frequency loop shaping method with the help of the derived mathematical model to ensure the stability of the system with robust dynamic behavior. The derived mathematical model provides a straightforward and efficient understanding of the dynamics resulting from the interaction between the PV and the SSI grid-connected system. The simulation results indicate that the system has a robust dynamic behavior when subjected to various transient conditions. Finally, a downscaled prototype of SSI grid-connected system is implemented to experimentally validate both the mathematical model and control strategy.

Hierarchical dual loop voltage and frequency control in stand alone microgrid with priority based intelligent load management

Hierarchical dual loop voltage and frequency control in stand alone microgrid with priority based intelligent load management

APELLA: Open-Source, miniaturized All-in-One powered Lab-on-a-Disc platform

We present an unconventional approach to a common Lab-on-a-Disc (LoD) that combines a quadcopter propulsion system, a miniaturized 2.4 GHz Wi-Fi spy camera, 9.74 Watt Qi wireless power, and an Arduino into an open-source, miniaturized All-in-one powered lab-on-disc platform (APELLA). The quadcopter propulsion generates thrust to rotate (from 0.1 to 24.5 Hz) or shake the LoD device, while the spy camera enables a real-time (30 frames per second) and high definition (1280 × 720 pixels) visualization of microfluidic channels without requiring a bulky and heavy stroboscopic imaging setup. A mobile device can communicate with an Arduino microcontroller inside the APELLA through a Bluetooth interface for closed loop and sequential frequency control. In a proof-of-concept study, the APELLA achieved comparable mixing efficiency to a traditional spin stand and can capture rapid microfluidic events at low rotational frequencies (<5Hz). The APELLA is low-cost (c.a. 100 Euro), compact (15.6 × 15.6 × 10 cm3), lightweight (0.59 kg), portable (powered by a 5 V USB power bank), and energy efficient (uses < 6% power of the conventional system), making it ideal for field deployment, education, resource-limited labs.

Improving the telescope guiding with field stabilization on the Very Large Telescope/Unit Telescopes

Acquisition and guiding services have been provided at major telescopes in order to improve the quality and efficiency of scientific observations. Field stabilization (FS) is an essential component of the telescope control system. With the arrival of new-generation instruments, the stabilization requirements have increased. Higher correction frequency is required to minimize the residuals. A major re-engineering of the CCD acquisition software now enables an increase of the operational frequency from 25 to 87 Hz. We analyze and discuss the performances of FS at various frequencies on the Very Large Telescope with its 8-m telescopes including the Adaptive 8-m telescope equipped with a deformable secondary mirror. We will report on the analysis of the residuals in function of several operational key parameters, e.g., the loop frequency, the magnitude of the selected telescope guide star, etc. We will also discuss the possible automatization of the FS during night operations.

Relation of Primary Fingerprint Patterns With Gender and Blood Group: A Dermatoglyphic Study From a Tertiary Care Institute in Eastern India.

Background Identification of an individual plays a vital part in any medicolegalinvestigation. The fingerprint is one of the oldestand most reliable biometric methods and is taken as legitimate proof of identification of an individual. Positive relationships between the fingerprint pattern and blood group and the fingerprint pattern and gender were demonstrated in some of the previous studies but weren't consistent across them. Objectives (a) To studythe distribution of fingerprint patterns among the study participants by gender and ABO and Rh blood groups and (b) to find an association between the fingerprint pattern andgender and blood group. Methods A cross-sectional observational study was carried out in the year 2021 on 800 healthcare students and workers of All India Institute of Medical Sciences, Patna, Bihar, Eastern Indiahaving different ABO and Rh blood groups. Healthy individuals i.e., those who were not suffering from any illness which can affect the fingerprints, aged 18 years or above were included and individuals having hand or finger deformities or missing fingers, having an allergy to the ink pad, and having blood group diseases were excluded. Rolled imprints of all the 10 digits of the participants were taken on a white A4 size Performa and were classified into loops, whorl, arches, and composite. The distribution of the fingerprint patterns was then compared by gender, ABO and Rh blood group. Chi-square/Fischer exact tests were applied to comparetwo groups andfind the association. P-value<0.05 was taken as statistically significant. Results The majority (66.0%) of the participants in the study were males with a male: female ratio of 1.9:1. Most common blood group was blood group B (37.7%) followed byO (29.8%), A (23.0%), and AB (9.5%). Rh-positive cases constituted around 96% of all the studied cases with the rest being Rh-ve. The general distribution of the fingerprint pattern showed a high frequency of loops registering 55.9%; followed by whorls (34.9%), arches (6.0%), and composite (3.1%). The distribution of fingerprint patterns among the male and femalegender was found to be similar with no significant difference (p=0.11). However, the distribution of the finger patterns across the ABO blood groups showed a statistically significant difference (p=0.0003) whereas it was non-significant across the Rh blood groups (p=0.08). Conclusion This study concludes that the distribution of the primary fingerprint patterns relates to the "ABO" blood group but not to gender and Rh blood group. An individual's fingerprints may be used to predict his/her blood group and vice versa.

Ultra-low noise bipolar current source for ultracold atom magnetic system.

We report the development of an ultralow-noise bipolar current source based on the configuration of H-bridge current switching. The measured relative current noise fluctuation reaches 4 × 10-9Hz-1/2, which enables an ultra-stable magnetic system for cold atom experiments. We avoid the influence of the AC leakage currents induced by the large parasitic capacitance of the H-bridge. First, the current sensor is placed as close as possible to the magnetic coils so that the systematic errors from these leakage currents are minimized. Second, the large parasitic capacitance, which parallels the magnetic coils and forms an LC oscillator, is removed from the feedback loop in our setup to maintain a large self-resonance frequency of the feedback control loop. These two improvements lead to a current source that is more precise and less noisy. Remarkably, the lowest current noise density produced by the proposed method is only 500 nA Hz-1/2 at a current of 100A, which is about ten fold smaller than the case with leakage current. To optimize the feedback control, a numerical simulation is implemented by using Matlab Simulink, and the numerical simulation results are entirely consistent with the experimental results.

A Multifrequency Small-Signal Model for the MLCL-Filtered Grid-Connected Inverter Considering the FCE of Nonlinear Inductors

To study the frequency coupling effect (FCE) of nonlinear inductors in frequency domain, a multifrequency small signal model is developed in this paper for the modified LCL (MLCL) filtered grid-connected inverter. This model is realized by extracting side band coupling (SBC) units out of the harmonic state-space (HSS) model and superposing them to the perturbation frequency loop. Compared with the complicated reductant HSS model, the proposed multifrequency model provides an intuitive efficient accurate way to describe the system. Besides, notions in classical control theory can be directly utilized with the multifrequency model. With this model, the current control loop of the inverter is studied. Besides, by introducing a simplified linear time invariant (LTI) small signal model (the FCE is ignored), it is found that the FCE effect is non-negligible especially in the frequency range around resonance points, which affects the stability of the differential mode resonance (DMR) and common mode resonance (CMR). The proposed multifrequency model accurately predicts the DMR and CMR stability, while the simplified LTI model fails. Furthermore, damping strategies are developed to suppress the DMR and CMR. Finally, simulations and experiments based on a 228 kW PV inverter are conducted to verify the analytical result.

3D-printed dual-band energy harvester for WSNs in green IoT applications

This paper describes the 3D-printed open Double Square Loop (DSL) Frequency Selective Surfaces (FSSs) based Radio Frequency energy harvester specifically designed for the purpose of capturing Wi-Fi ambient RF energy. The proposed dual-band energy harvesting circuit is a suitable applicant for low-power green IoT Wireless Sensor Networks. The inclusion of FSS in the receiver improved the antenna’s gain by 42% and 74% at 2.4 GHz and 5.2 GHz, respectively, and consequently, enhanced the conversion efficiency. Due to FSS-backed dual-band antenna, the proposed configuration gathers a significant amount of RF ambient energy from the surroundings. The collected RF energy is then converted into DC voltage using a three-stage Villard RF rectifier cum multiplier. The Fused Deposition Modeling (FDM) of 3D printing is employed to create the designed prototype on a biodegradable Polylactic Acid substrate. RF measurements are taken with horn antenna and signal generator to evaluate the proposed design. At 2.4 GHz, the constructed prototype has a conversion efficiency of 67.90% and a corresponding output voltage of 2.36 V, whereas, at 5.2 GHz, it achieves an efficiency of 34.01% with output voltage of 1.67 V, at 0 dBm input power. The proposed configuration has a good correlation between simulated and measured outcomes.

Assessment of Palmar Patterns and Dermatoglyphics in Oral Cancer Patients of Bareilly City: An Observational Study

Background and objectives: Dermatoglyphics are the dermal ridge configuration on the digits, palms and soles. Dermatoglyphics may be used as an easily accessible tool in the study of genetically induced diseases as genetic or chromosomal defects may be expressed as alterations in dermal ridges. They are genetically determined and influenced by environmental forces that are operating before birth. Several studies have shown an association between dermatoglyphics and different types of cancer. Hence this study was undertaken to determine whether specific dermatoglyphic patterns exist that help in predicting the occurrence of oral squamous cell carcinoma.&#x0D; Aim: This study was conducted to study palmar and dermatoglyphic patterns in oral carcinomas patients in Bareilly city.&#x0D; Material and method: Our study was conducted among 59 subjects having oral cancer in Bareilly city. A modified case history proforma and comprehensive history was taken. Finger and palm prints were collected from Oral squamous cell carcinoma (OSCC) patients using the digital method and were evaluated qualitatively and quantitatively using an appropriate statistical test.&#x0D; Results: Finger and palm prints were evaluated qualitatively and quantitatively. Significant findings in patients with oral squamous cell carcinoma in both hands were: Increased frequency of Loops and whorls, Loop patterns are common in Thenar/I1 area, Increased Total finger ridge count on the right hand, increased ab count on the left hand, more atd angle on the left hand.&#x0D; Conclusion: Our study concluded that dermatoglyphic patterns may have a role in identifying individuals either with or at risk for developing oral squamous cell carcinoma. It can be used to identify high-risk group so that early primary and secondary preventive measures can be instituted to prevent the occurrence of these lesions.

Hardware-efficient and accurately frequency offset compensation based on feedback structure and polar coordinates processing

Compared with off-line digital signal processing (DSP) verification, achieving the expected performance and hardware efficiency in application specific integrated circuit (ASIC) is more critical for DSP to reduce power consumption and cost. The performance of traditional frequency offset compensation algorithms based on feedforward structure is strongly dependent on the accuracy of frequency offset estimation. Therefore, frequency offset calculation and loop filtering implemented in ASIC or field programmable gate array (FPGA) usually choose high word-width fixed-point or floating-point operations, which increase the consumption of logical resources and reduce the clock frequency that hardware logic can achieve. This work proposes a frequency offset compensation scheme based on polar coordinate processing and feedback structure, and a pre-decision-based angle differential estimator is used to estimate the residual frequency offset. In the proposed feedback structure, the frequency offset estimator is realized by a simple accumulator, and the input of the accumulator is the residual frequency offset or its scaling, which will reduce the requirement for the accuracy of the residual frequency offset estimator. The offline verification results show that the performance of the proposed algorithm is close to that of the traditional algorithm, but the proposed algorithm has lower logic resource consumption and higher clock frequency in hardware implementation based on FPGA. The performance of the proposed method is evaluated in real-time through 10-Gbps data rate polarization-multiplexed quadrature phase shift keying modulation after 20-km standard single-mode fiber transmission. Compared with offline processing in MATLAB®, no hardware implementation penalty is observed.