Low Deviation Research Articles

Unicompartmental knee arthroplasty implant survival in patients with borderline indications.

In the literature, 80% to 92% of patients are satisfied with their medial femorotibial unicompartmental knee arthroplasties (UKAs). These results are associated with a 10-year implant survival rates ranging from 94% to 98% in various studies. Such outcomes are generally reported after excluding patients with obesity, chronic anterior instability, frontal deformities, or preoperative knee flexion deformities exceeding 10 °. These contraindications remain controversial in the literature. The primary objective of this study was to compare the survival rates of implants used for medial femorotibial UKA performed under borderline indications with those of procedures performed under conventional indications and to identify the prognostic factors for revision surgery. We hypothesized that the survival of medial femorotibial UKAs is not impacted by these contraindications. This was a retrospective, single-center, observational, epidemiological study. All consenting patients who underwent medial femorotibial UKA between 2009 and 2015 were included. Patients who underwent other types of arthroplasties concurrently were excluded. The primary evaluation criterion was implant survival, which was characterized by no need for revision surgery. The borderline indications were defined as follows: obesity (Body Mass index BMI > 30), anterior cruciate ligament (ACL) deficiency, preoperative lower limb frontal deviation ≥10 °, or preoperative flexion deformity ≥10 °. A total of 468 patients were included, and the average follow-up duration was 8.5 years [7.1; 10.3]. Among them, 270 (57.7%) underwent UKA under at least one borderline indication, whereas 198 (42.3%) underwent UKA under conventional indications. Forty revision surgeries were recorded, and the average time to revision surgery was 26 months. No statistically significant difference in survival was observed between patients with borderline indications and those with conventional indications. Multivariate analysis revealed that obesity (HR = 3.0 [1.5-5.7]) and ACL deficiency (HR = 3.5 [1.4-8.8]) significantly increased the risk of revision surgery. This study revealed no significant difference in survival between UKAs performed under borderline versus conventional indications. Larger studies are needed to confirm these findings. IV; retrospective observational study. Mots clés: genou, arthroplastie, obésité, ostéoarthrite, survie.

Blood volume deficit in postural orthostatic tachycardia syndrome assessed by semiautomated carbon monoxide rebreathing

Abstract Purpose The semiautomated carbon monoxide (CO) rebreathing method has been introduced as a noninvasive and radiation-free blood volume estimation method. We tested whether the semiautomated CO rebreathing method can detect the blood volume deficit in postural orthostatic tachycardia syndrome (POTS). In addition, we explored the relationship between blood volume estimated from CO rebreathing and body impedance. Patients and methods We recruited 53 subjects (21 female patients with POTS, 19 healthy female participants, and 13 healthy male participants) to record blood volumes and hemodynamic data. Blood volumes were measured by CO rebreathing and segmental body impedance. Linear regression models to predict normal values of red blood cell volume (RBCV), plasma volume (PV), and total blood volume (BV) were developed. Percentage deviations from the predicted normal volumes were calculated. Results Patients with POTS had lower RBCV (25.18 ± 3.95 versus 28.57 ± 3.68 mL/kg, p = 0.008, patients with POTS versus healthy female participants), BV (64.53 ± 10.02 versus 76.78 ± 10.00 mL/kg, p < 0.001), and BV deviation (−13.92 ± 10.38% versus −0.02 ± 10.18%, p < 0.001). Patients with POTS had higher supine heart rate (HR) (84 ± 14 versus 69 ± 11 bpm, p < 0.001) and upright HR (123 ± 23 versus 89 ± 22 bpm, p < 0.001). We found a correlation between BV deviation and upright HR in patients with POTS (r = −0.608, p = 0.003), but not in healthy participants. Volumes from the CO rebreathing and body impedance were well correlated (r = 0.629, p < 0.001). Conclusions The CO rebreathing method can detect BV deficit, as well as the RBCV deficit in patients with POTS. The negative correlation between BV deviation and upright HR indicates that hypovolemia is one of the pathophysiological causes of POTS. Correlations between body impedance and CO rebreathing volume suggest its usefulness for measurements of volume changes.

Dynamic constitutive modelling and mullins effect of elastic‐porous metal rubber

AbstractElastic‐porous metal rubber, commonly employed in dynamic environments, has received special attention nowadays. Utilization of equivalent metal rubber models in the finite element analysis becomes imperative because of the complexity of the spatial network structure and the extensive numerical calculations involved in it. In this work, the nonlinear characteristics of metal rubber are represented by hyperelastic constitutive models, and the Mullins effect is discussed. The relative deviations of the displacement‐load curve among the test results and three dynamic models are analyzed: the hysteretic Bergström–Boyce model, the viscoelastic generalized Maxwell model, and the nonlinear spring‐viscous damping element model. The results indicate that the damage value of the Mullins effect is positively correlated with the magnitude of the strain during unloading, and the performance degradation of metal rubber is weakened after multiple cycles. The time domain characteristics of the generalized Maxwell model demonstrate that the dynamic analysis of metal rubber at different frequencies have obvious deviations. The rate correlation of metal rubber affects the dynamic stiffness under different amplitudes This is reason that the nonlinear spring‐viscous damping element model is deviated. Regardless of the frequency or amplitude, the Bergström–Boyce model has been found to exhibit a lower relative deviation and match well with the dynamic experiment.

Thermodynamic Modeling of an Aqueous N, N-Dimethyldipropylenetriamine and Benzylamine Blend for Efficient CO2 Capture.

This study evaluates the carbon dioxide (CO2) capture capabilities of a novel aqueous blend of N,N-dimethyldipropylenetriamine (DMDPTA) and benzylamine (BA). The solvent properties such density, vapor- liquid equilibrium (VLE) of CO2 in the solvent, CO2 absorption enthalpy are evaluated experimentally for solvent composition of (5 mass % DMDPTA+25 mass % BA), (10 mass % DMDPTA+20 mass % BA), and (15 mass % DMDPTA+15 mass % BA). Solvent density were measured in the temperature range of 303 K-333 K and correlated using Redlich-Kister excess molar volume model, with a low average absolute relative deviation (AARD) of 0.014. VLE data was measured using a custom-made stirred VLE cell, within CO2 partial pressure range of 2-200 kPa and at temperatures 313 K, 323 K and 333 K. Equilibrium CO2 solubility data were correlated using a modified Kent-Eisenberg model, achieving an AARD of 1.5 %. Enthalpy of CO2 absorption was measured at 313 K using a Meter Toledo reaction calorimeter. Results indicated that under similar process conditions and solvent composition, (DMDPTA+BA) blends exhibited significantly higher CO2 loading and low absorption enthalpy compared to aqueous BA and monoethanolamine solvent alone indicating the potential of (DMDPTA+BA) blend as efficient CO2 capture solvent.

Moisture Distribution and Ice Front Identification in Freezing Soil Using an Optimized Circular Capacitance Sensor.

As the interface between frozen and unfrozen soil, the ice front is not only a spatial location concept, but also a potentially dangerous interface where the mechanical properties of soil could change abruptly. Accurately identifying its spatial position is essential for the safe and efficient execution of large-scale frozen soil engineering projects. Electrical capacitance tomography (ECT) is a promising method for the visualization of frozen soil due to its non-invasive nature, low cast, and rapid response. This paper presents the design and optimization of a mobile circular capacitance sensor (MCCS). The MCCS was used to measure frozen soil samples along the depth direction to obtain moisture distribution and three-dimensional images of the ice front. Finally, the experimental results were compared with the simulation results from COMSOL Multiphysics to analyze the deviations. It was found that the fuzzy optimization design based on multi-criteria orthogonal experiments makes the MCCS meet various performance requirements. The average permittivity distribution was proposed to reflect moisture distribution along the depth direction and showed good correlation. Three-dimensional reconstructed images could provide the precise position of the ice front. The simulation results indicate that the MCCS has a low deviation margin in identifying the position of the ice front.

Detection of Modulated Wave Transmission Failure in Aviation Communication Using IoT-Based RTL-SDR

Communication is a crucial component in aviation telecommunications services, where failures can lead to fatal incidents that may result in loss of life. According to Regulation No. 48 of 2017, aviation telecommunication service providers must be able to provide VHF A/G services with an availability value of 0.99999 and detect failures within two seconds. At Perum LPPNPI Yogyakarta, the VHF A/G equipment is located in a transmitter building 760 meters away from the Technician Standby Building. This distance makes it difficult for technicians to directly monitor the equipment's condition, leading to failures being identified based on reports from air traffic controllers. Therefore, the author designed an IoT-based RTL-SDR system to directly monitor equipment conditions based on the modulated waves transmitted. This design employs the ADDIE method in its development. The system operates by measuring the transmission power and audio level of the modulated waves. Based on research conducted at frequencies 120.2 MHz, 125 MHz, 126.7 MHz, 127 MHz, 129.5 MHz, 130 MHz, 132.5 MHz, 133.2 MHz, 134 MHz, and 135 MHz, this design can detect equipment failures based on the received modulated waves with highest and lowest deviation while measuring transmission power are 2.24 dB and 0.4 dB.

Radiological Approach to Assessment of Lower-Limb Alignment-Coronal and Transverse Plane Analysis.

Lower-limb alignment deformities constitute a significant clinical concern, as they can lead to serious complications, including progressive degenerative diseases and disabilities. Rotational deformities may give rise to conditions such as joint arthrosis, patellar instability, and the degeneration of the patellofemoral cartilage. Therefore, a comprehensive evaluation of lower-limb alignment is essential for the effective patient management, preoperative planning, and successful correction of these deformities. The primary assessment method employs full-length standing radiographs in the anteroposterior (AP) projection, which facilitates accurate measurements of the anatomical and mechanical axes of the lower limb, including angles and deviations. The outcomes of this analysis are vital for the meticulous planning of osteotomy and total knee arthroplasty (TKA). In addition, computed tomography (CT) provides a specialized approach for the precise evaluation of femoral and tibial rotation. In this area, there are potential opportunities for the implementation of AI-based automated measurement systems.

Sustainable Spectrophotometric Quantification of Lansoprazole Through Mixed Hydrotropy Approach

Solubility is the property of a substance to dissolve in or form a homogeneous mixture with another substance. One of the most common problems associated with making a solution is poor solubility. There are many drugs that are sparingly soluble or insoluble in water, and lansoprazole is one of them. Aqueous solubility of lansoprazole is 0.05 mg/ml at room temperature. The current study aims to improve lansoprazole solubility using a mixed hydrotropy method. The purpose of the mixed hydrotropic solubilization approach is to increase the solubility of weakly water-soluble drugs in hydrotropic agent blends. To avoid the use of organic solvents, the mixed hydrotropy idea may be a good option. In this current research attempt, a novel method for spectrophotometric estimation of lansoprazole using a mixed solvent blend (containing 10% SC and 20% SB) as the solvent was developed. By observing the absorbances of the drug's standard solutions, the calibration curve for lansoprazole was drawn. The absorbances were measured at 275 nm compared to the corresponding reagent blanks. The percent label claims were found to be very near to 100, showing that the proposed approach is accurate. The suggested method estimates percent recoveries to be near 100 with significantly low percentage deviation and standard error values. As a result, the proposed process is simple, safe, and precise, and it does not require the use of harmful chemical solvents.

Gas–Water–Sand Inflow Patterns and Completion Optimization in Hydrate Wells with Different Sand Control Completions

Sand production poses a significant problem for marine natural gas hydrate efficient production. However, the bottom hole gas–water–sand inflow pattern remains unclear, hindering the design of standalone screen and gravel packing sand control completions. Therefore, gas–water–sand inflow patterns were studied in horizontal and vertical wells with the two completions. The experimental results showed that gas–water stratification occurred in horizontal and vertical standalone screen wells. The gas–water interface changed dynamically, leading to an uneven screen plugging, with severe plugging at the bottom and high permeability at the top. The high sand production rate and low well deviation angle exacerbated screen plugging, resulting in a faster rising rate of the gas–water interface. The screen plugging degree initially decreased and then increased as the gas–water ratio increased, resulting in the corresponding variation in the gas–water interface rising rate. Conversely, gas–water stratification did not occur in the gravel packing well because of the pore throat formed between the packing gravels. However, the impact of gas and water led to gravel rearrangement and the formation of erosion holes, causing sand control failure. A higher gas–water ratio and lower packing degree could result in more severe destabilization. Therefore, for the standalone screen completion, sand control accuracy should be designed at different levels according to the uneven plugging degree of the screen. For the gravel packing completion, increase the gravel density without destabilizing the hydrate reservoir, and use the coated gravel with a cementing effect to improve the gravel layer stability. In addition, the screen sand control accuracy inside the gravel packing layer should be designed according to the sand size to keep long-term stable hydrate production.

Low-noise soliton molecule generation with an in-phase controllable pulse number by third- and second-order dispersion compensation in an all-fiber erbium-doped oscillator

We report on the experimental results of high-order soliton molecule (SM) generation in an erbium-doped oscillator. The generation of 14 solitons with an average power of 48 mW, a pulse duration of 508 fs, a separation of 2.59 ps between pulses, and a repetition rate of 19 MHz at 1560 nm central wavelength was demonstrated. The stability of this generation was also evidenced by its low relative intensity noise (0.08% in the frequency range [10 kHz–1 MHz]), and a low Allan deviation of frequency repetition rate of 1.98⋅10−9 at an interval of 1 s (during 10 h of free-running measurements). Moreover, the accurate manipulation of SM order by changing the pump power was investigated; we showed the ability to generate with four, six, seven, nine, 10, 11, 13, and 14 pulses with high stable states between solitons. The change in the number of pulses occurred repeatably by increasing and decreasing the pump power, offering a stable source of a controllable number of pulses for potential applications in quantum computing.

Transient convective heat transfer analysis in dull cornered triangular enclosure with open-cell metal foam and hybrid nano fluid

Transient convective heat transfer is a type of heat transfer that occurs when fluid convection changes in temperature, heat flux, or velocity over time. However, the heat transfer phenomenon in porous media under transient situations has not been extensively examined in current research, and only a few studies have focused on triangle enclosures. Thus, a novel Dull Cornered Triangular Enclosure with Bottom separated Open-Cell Aluminum Metal Foam and Hybrid Nano Fluid is introduced. Neglecting viscous dissipation and thermal dispersion in porous media in the prevailing studies leads to underestimated temperature rises. Hence, a novel DMW-GO-MWCNT nanofluid is used as a coolant, featuring 2% graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs), enhancing convective heat transmission. Including viscous dissipation and thermal dispersion in transient simulations accurately models temperature rises, avoiding suboptimal designs. The sharp lower corners in traditional triangle enclosures create stagnation points, disrupting uniform heating or cooling and reducing heat transfer efficiency. Thus, a Dull Cornered Triangular Enclosure is designed to eliminate recirculation zones by rounding the bottom corners, improving heat transfer efficiency. The placement of porous media in contact with heating surface enclosures hinders transient convective heat transfer, leading to dominant conductive heat transfer, increased cavitation risk, reduced Nusselt number, and impaired overall convective heat transfer efficiency. Therefore, incorporating Bottom Separated Open-Cell Aluminum Metal Foam in the proposed triangular enclosure lowers pressure drop and increases the Nusselt number with increased convective heat transfer efficiency. The results show that the proposed model has improved the overall transient convective heat transfer performance with a high Nusselt number, thermal conductivity, thermal expansion coefficient, effectiveness, heat transfer coefficient, heat transfer rate; and low deviation time, skin friction coefficient, and pressure drop.

Effect of magnetic resonance imaging protocol on decision-making for positioning of dental implants in edentulous cases.

This study aimed to assess the influence of magnetic resonance imaging (MRI) protocol on the decision-making for the positioning of dental implants in edentulous arches in comparison to planning based on cone beam computed tomography (CBCT). One phantom was scanned with CBCT and two MRI protocols (T1- and T2-weighted). Two calibrated examiners performed digital implant planning (coDiagnostiX, Dental Wings), considering a digital prosthetic planning and alveolar ridge surface scan. Four implants were planned for each patient dataset, and the angular deviation between the long axis of the implants and the prosthetic planning occlusal plane was measured. Each examiner planned 40 implants, 12 implants with CBCT and 28 implants with MRI (16 with T1 and 12 with T2 images). Significant differences in angle deviation were observed between CBCT, T1, and T2 in the anterior region for both examiners (p=0.009 for examiner 1 and p=0.042 for examiner 2). Implants planned with CBCT showed significantly lower angular deviation than those based on the T1 and T2 scans for both examiners (p=0.028 and p=0.046 for examiner 1 and p=0.028 and p=0.027 for examiner 2). No significant difference in angular deviation was found between T1 and T2 for both examiners (examiner 1: p=0.600, examiner 2: p=0.916). Compared to CBCT planning, the MRI protocol influenced decision-making for anterior dental implants, with angular deviations within acceptable clinical thresholds, but further studies are needed to validate these findings.

Effect of Metal Artifacts in Cone-beam Computed Tomography on Accuracy of Implant Placement by Static and Dynamic Computer- Assisted Implant Surgery: An In Vitro Study.

This study evaluates the impact of metal artifacts in cone-beam computed tomography (CBCT) on the accuracy of static and dynamic computer-assisted implant surgery (CAIS) techniques. An implant was placed on each of thirty 3D-printed models embedded with Cobalt-Chrome strips to simulate metal artifacts by Porcelain-fused-to-metal (PFM), utilizing these CAIS techniques: radiographic template (RT) (n=10), radiographic markers (RM) (n=10), and dynamic navigation (DN) (n=10). Trueness and precision were analyzed by comparing 3D global deviation and the difference in implant positions at the neck, apex, depth, and angle in initial planned and final placed scans. DN exhibited significantly lower 3D global trueness deviation to RT (p = 0.022) and lower angular deviation compared to both RT (p = 0.003) and RM (p = 0.002). RM showed greater trueness at the implant neck compared to DN (p = 0.005) and better depth trueness than RT (p = 0.001) and DN (p = 0.027). DN demonstrated higher precision in implant angulation than RM (p = 0.011) and RT (p = 0.041). In the presence of metal artifacts, both DN and RM techniques offered greater trueness in specific implant positions compared to RT. However, DN proved to be the most precise method for implant placement.

Accuracy of repaired maxillary dentures from two different repairing techniques: In vitro study

BackgroundDenture fracture is a common problem with acrylic dentures. The fractured denture can be repaired using various techniques such as self-cure acrylic resin acrylic resin and fiber-reinforced acrylic resin. PurposeThe purpose of this study was to compare the accuracy of dentures repaired with self-cure acrylic resin and fiber-reinforced acrylic resin processed using two different techniques (long-cure and microwave processing). Materials and methodsA total of 20 maxillary complete dentures were processed with two techniques; heat (long cycle) processing (10 dentures) and microwave processing (10 dentures). The maxillary cast and denture surface were scanned with Medit intraoral (Medit i700, Medit, South Korea) and STL files were created. Then, the dentures were sectioned at the midline and repaired using self-cure acrylic resin and fiber-reinforced acrylic resin and scanned with Medit intraoral. Finally, adaptation deviations were analyzed from computer software (Geomagic Control X, 3D Systems Inc., USA). The adaptation deviations in each group (long cure and microwave) were compared using an Independent T-test. Two-way ANOVA was done to see whether curing techniques and repairing methods affect the accuracy of repair. A P-value of 0.05 was considered significant. ResultsThe adaptation deviation was slightly higher in the fiber-reinforced acrylic resin group (0.565 ± 0.093) than in the self-cure acrylic resin group (0.536 ± 0.066). However, there was no statistical difference in the adaptation deviations of repaired dentures with self-cure acrylic resin and fiber-reinforced acrylic resin in the long-curing (P-value 0.245) and the microwave (P-value 0.638). Similarly, the adaptation deviation was slightly higher in the long-curing group (0.577 ± 0.075) than in the microwave group (0.524 ± 0.079). However, there was a statistically significant difference in the adaptation deviation of repaired dentures between long-curing and microwave techniques with self-cure acrylic resin (P-value 0.016) but no difference in fiber-reinforced acrylic resin (P-value 0.127). The result of Two-way ANOVA shows that there is no statistically significant interaction between curing techniques (long curing and microwave) and repairing methods (self-cure acrylic resin and fiber-reinforced acrylic resin) for adaptation deviations (P-value 0.646). However, the curing techniques show statistically significant differences (P-value 0.039). ConclusionAcrylic dentures can be repaired with self-cure resin or fiber-reinforced self-cure resin using various processing methods. The accuracy of the denture after repair is unaffected by the repairing method (self-cure acrylic resin and fiber-reinforced acrylic resin) but the accuracy of the denture after repair is affected by the curing techniques (long-curing and microwave). In self-cure resin, the microwave processing showed higher adaptation deviation and less accuracy, whereas the long-curing processing showed lower adaptation deviation and high accuracy.

Parameter estimation in vapor-liquid equilibrium modeling of compounds related to biodiesel production using opposite point-based differential evolution algorithm.

Biodiesel stands out as the most favorable alternatives to fossil-derived diesel, offering a multitude of environmental benefits. At various stages of biodiesel production, the separation processes necessitate thermodynamic models with the capability to correlate and predict phase equilibria of mixtures. In this study, application of the classical differential evolution (DE) and its new enhanced version, the OPDE algorithm, for modeling vapor-liquid equilibrium (VLE) associated with components related to biodiesel production is presented. The algorithms were analysed and contrasted in terms of their performance, in estimating parameters for Wilson, NRTL and UNIFAC models. Additionally, classical least-squares (LS) and error-in-variable (EIV) approaches were examined and compared. Also, VLE datasets for a specific system have been merged, and parameters have been estimated. The findings suggest that parameters obtained through LS approach align with those reported in literature, indicating faster convergence in all problems. In contrast, the EIV approach achieved a higher objective function value compared to the LS approach, exhibiting low deviation. OPDE outperformed DE in terms of performance. The enhancement in RMSTD value has been found within range 91%-99% for EIV approach. Further, novel findings derived from some of the studied VLE datasets are presented.

Implementation of reengineering technology in the technological preparation for general aviation airplane wing tip manufacturing based on the construction of a digital mock-up

The object of this study is the technological preparation of the production of a light aircraft wing using reverse engineering technology. The subject of research is a quality indicator – the geometric accuracy of manufacturing the convex-concave parts of aerospace technology. Calculations of geometric accuracy were performed for the program-instrumental method of co-ordination. As the experimental part it was taken the worn out wing tip of a light aircraft. The following results were obtained. An approach for specifying the aerodynamic airfoil and cross sections of the wing tip when constructing its digital model has been proposed. A 3D scanning of the wing tip with the formation of a digital portrait in STL format, as well as its refinement into a STEP format, using organic and mechanical methods, was accomplished. A digital mock-up of the wing tip was built taking into account the geometry of the aerodynamic airfoil in cross sections as well as a digital mock-up of the form (mould) for its manufacture according to the polygonal model, which was created by the organic method due to it had the highest dimensional accuracy. It was determined that the maximum deviation of the actual wing contour from the theoretical one was as follows: the upper deviation was 0.84 mm, the lower deviation was –0.65 mm. The maximum deviation of the actual wing contour from the theoretical one was ±0.3 mm. The expected (calculated) errors did not exceed the specified value of the tolerance on the wing outer contour that equal to ±1.0 mm, thus, the adopted method of assembling the wing under the conditions of co-ordination by the program-instrumental method ensured the specified geometric accuracy. The results of experimental studies confirmed the adequacy of the proposed approach for determining the aerodynamic airfoil of the cross-sections of the digital mock-up of convex-concave parts for aerospace technology during their technological preparation for production with the use of reverse engineering.

Numerical and experimental frequency analysis of damaged fiber‐reinforced metal laminated composite

AbstractThis research numerically evaluated the eigenvalue responses of the damaged fiber metal laminate (FML) structure. The current numerical model is delved into including crack‐type damage effect on the structural integrity/ stiffness via frequency response. In this regard, a complete mathematical model of FML has been derived through higher‐order shear deformation kinematics for computational purposes. The mathematical model is converted to computer code in the MATLAB platform to predict the eigenvalue responses of FML components with and without damage. The damage influences are considered via circular meshing of finite element steps associated with the isoparametric element (nine nodes and nine degrees of freedom for each node). The solution consistency is checked via convergence, and the results are compared with data available in the open domain. Further, an experimental test is carried out to improve confidence using an in‐house test rig. The experiment was conducted by varying the length of the FML in 0.1 m increments. The results showed good agreement between the numerical and experimental data, with the lowest deviation being 0.29% and the highest 8.97%. The developed numerical model is extended to analyze the influences of design parameters such as geometry shape, aspect ratio (a/b), thickness ratio (a/h) ratio, curvature ratio, and fiber layup sequence on the natural frequency response.

Towards non-virtual inertia control of renewable energy for frequency regulation: Modeling, analysis and new control scheme

Currently, when renewable generation participates in frequency regulation, the traditional control method is to emulate synchronous generators through virtual inertia control. However, virtual inertia has a time delay, so essentially, it is a fast power response. Meanwhile, virtual inertia control is likely to be affected by frequency fluctuation since it responds to the derivative of frequency. Hence, it’s worth exploring non-virtual inertia control for renewable energy when participating in frequency regulation. For this reason, a novel two-segment droop control scheme for renewable energy frequency regulation is proposed in this research. Firstly, the extended system frequency regulation (SFR) model, which contains virtual inertia with time delay, is built and analytically solved by order decrement based on the Routh approximation method. Afterwards, according to the analytical solution, time delay affects the frequency response of renewable energy. It can also be analytically proved that the non-virtual inertia control, e.g., sole droop control, could replace virtual inertia under the same frequency deviation. Still, more energy may be needed for frequency regulation. Furthermore, a novel two-segment droop control is presented, and to analytically prove its ability to replace virtual inertia, the impulse function balancing principle and the integration by parts algorithm were adopted to address the initial conditions of the differential equation. Based on the analytical expression, it can be analytically proved that a lower frequency deviation can be obtained under the same frequency regulation energy. Accordingly, a parameter-setting method for two-segment droop control was proposed. Finally, the effectiveness of the proposed method is verified by using a two-area system frequency response model, and the results reveal that it can be used to replace virtual inertia and has better performance.

A novel technique to resolve directional ambiguity for Particle Streak Velocimetry

In this study, a novel streak direction-resolving algorithm is introduced to determine the direction of the flow field for a single image frame with multiple streaks. The streak direction was resolved by varying its intensity from 100 % to 50 % of the total intensity of the streak image. This technique was applied to two main types of flows parallel and Hill's vortex flows, parallel flows were divided into further two types constant velocity parallel flow and accelerating parallel flow. The purpose of using different types of flows was to test the robustness of the algorithm with easy and complex flows. The performance of the algorithm was checked by the angular deviation between the true and least-square fitted velocity vectors. The number of correct synthetic streak directions was measured with the success rate in percentage. A high success rate means low angular deviation and a high number of velocity vectors with correct direction was obtained. In this research, four different types of image formats were considered DP (double precision), 16-bit (without noise), 16-bit (1.0 % noise), 16-bit (5.0 % noise), and 8-bit (without noise) and the best results were obtained for DP and 16-bit image formats. The results of the parallel flows indicated a 100 % streak direction success rate, Hill's vortex was a type of complex flow therefore, the algorithm hard to resolve some streak directions due to very low velocities (less than 0.1 px (pixel)/interval) and very high-velocity gradients (greater than 52 px/interval). The observation shows that Hill's vortex synthetic streak images were resolved with a success rate of 92.76 % which means that the majority of the synthetic streaks were resolved. Experimental analysis was also done by using the PDMS microchannel setup. Intensity variation streaks were recorded with long camera exposure time and for maintaining the intensity variation, as the LED switched on maximum illumination was started, and continuous decrement in illumination was set by switching off at 50 % of the total illumination intensity. The best results were achieved with a 94 % success rate. Therefore, the proposed novel approach can be used with less expensive hardware for image processing with a single image frame and is useful for multiple applications.

Evaluation of tamoxifen analogues as potential estrogen receptor alpha inhibitors for breast cancer treatment: A computational approach

Estrogen receptors, particularly ERα, play a key role in breast cancer progression, making them prime targets for therapeutic intervention. Tamoxifen (TAM), a selective estrogen receptor modulator (SERM), has been widely used for the treatment of ER+ breast cancer; however, its clinical application is limited by side effects and the emergence of resistance. This study aims to identify and evaluate TAM analogues with improved efficacy and reduced side effects by employing molecular docking and molecular dynamics (MD) simulations. Droloxifene, endoxifen, and afimoxifene emerged as promising candidates, exhibiting strong binding affinities with ERα, as indicated by highly negative binding energy (BE) values in docking simulations. MD simulations further validated the stability of the complexes formed between these analogues and ERα, with low root mean square deviation (RMSD) values and stable radius of gyration (Rg) profiles. Root mean square fluctuation (RMSF) analysis revealed balanced flexibility, with droloxifene and afimoxifene showing optimized flexibility for stable binding. Hydrogen bond analysis indicated more stable interactions between these analogues and ERα compared to TAM, suggesting enhanced binding affinity. MM/GBSA binding free energy analysis confirmed the high affinity of these analogues, with droloxifene displaying the most effective binding free energy (ΔGtotal) value. ADMET profiling suggests that droloxifene and endoxifen have superior pharmacokinetic properties relative to TAM. Overall, droloxifene, endoxifen, and afimoxifene represent promising alternatives to TAM, with the potential for further clinical development in breast cancer treatment. Experimental validation in cell-based and in vivo models will be crucial in future studies to confirm their efficacy and safety profiles.