Wind Stability Research Articles

Femtosecond laser-assisted cataract surgery (FLACS) versus conventional phacoemulsification in cataract management: a systematic review

Background: Cataracts remain the leading cause of reversible blindness and visual impairment worldwide. While phacoemulsification surgery (PCS) remains a highly effective and safe procedure, its success can be influenced by associated complications. Femtosecond laser-assisted cataract surgery (FLACS) has emerged as an alternative, offering greater safety, efficacy, and predictability, particularly for complex cataracts. Objective: This study aims to compare FLACS with PCS to evaluate differences in outcomes such as uncorrected distance visual acuity (UDVA), best-corrected visual acuity (BCVA), endothelial cell density (ECD), endothelial cell loss (ECL), and intraoperative complications. Materials and Methods: Following PRISMA guidelines, a systematic review was conducted. Studies published between 2015 and 2021 were identified through databases including PubMed, ScienceDirect, and Cochrane Library. Included studies involved cataract patients undergoing either FLACS or PCS, with outcomes measured for visual acuity, corneal cell integrity, and surgical complications. Results: FLACS demonstrated faster recovery in UDVA and BCVA within the initial postoperative period compared to PCS, although visual acuity results were similar by three to 12 months. While short-term endothelial preservation was similar, FLACS was associated with slightly higher long-term ECL, suggesting that PCS may better preserve corneal health over time. Complications such as anterior capsule tears were more frequent in FLACS. However, serious events were rare across both groups. FLACS yielded more precise corneal incisions, which may contribute to more stable wound healing during the early recovery stage. Conclusion: FLACS offers advantages in early postoperative visual recovery. However, PCS may provide slightly better long-term endothelial preservation. Both techniques ultimately result in similar visual outcomes in the long term, with FLACS presenting unique yet manageable intraoperative risks

A new concept reduced scale aeroelastic model of the four-cable suspension bridge with truss girder and its validation

The accuracy of the aeroelastic model or truss girders has consistently been a decisive factor influencing the results of full-bridge aeroelastic wind tunnel tests. A novel design approach, termed the Multi-Spine Frame System, is introduced for the reduced-scale model of the stiffening girder. This system incorporates multiple spines, thinner beams and columns to minimize aerodynamic interference while accurately simulating overall stiffness, mass, and constraints. The design procedure is formulated as an optimization problem with the objective of optimizing the low-order natural frequencies (lateral bending, vertical bending, and torsion) of the aeroelastic model. Pattern search method and penalty functions are employed to identify a locally optimal solution that satisfies engineering applications for this optimization problem. This design method is applied to an actual project involving a four-cable suspension bridge with a truss girder, and the test results demonstrate the accuracy of this approach in simulating the dynamic characteristics of the aeroelastic model. Corresponding wind tunnel tests on flutter instability, as well as numerical multi-modal flutter analysis, are conducted to analyze the critical flutter speed, vibration shapes, and frequencies of this bridge. Furthermore, the impact of deviation in structural mode shapes and natural frequencies on flutter instability is investigated using ten design schemes achieved by altering boundary conditions, mass distributions, and stiffness distributions, were examined. Significant differences in critical flutter speed (up to 9%) are observed due to deviations in mode shapes, emphasizing the necessity of considering modal frequencies and other modal information, such as mode shapes, in aeroelastic model design. This approach contributes to the advancement of aeroelastic model design for bridges with truss girders by introducing an effective system and an optimization method, providing a basis for future studies on wind instability and structural dynamics and also underscores the importance of accurate mode shape representation in flutter analysis.

Cost and Efficiency analysis of the Secondary electric machine in a CRAFT wind turbine

Abstract Floating offshore wind turbines are ideal for deeper waters, providing access to stronger and more stable winds. The Counter-Rotating Axis Floating Tilting (CRAFT) turbine features a unique design with two counter-rotating turbines on a tilted vertical shaft and two independent electrical machines submerged below sea level. The primary generator, connected to both turbines, includes counter-rotation which doubles the relative torque, while the secondary machine controls the upper turbine. This study examines the impact of primary and secondary machine efficiency on electricity generation. The findings indicate that the primary generator’s efficiency is crucial for system stability, whereas the secondary machine’s efficiency is less critical. Reducing the secondary machine’s efficiency from 97% to 83% resulted in a 0.1% reduction in annual electricity generation. Despite the asynchronous machine’s lower efficiency, it is the economically favorable choice as the secondary machine over its synchronous counterpart due to its reduced design complexity and lower magnet costs, leading to lower overall expenses. Future research investigate how turbulent flow effects and airflow interactions between the turbines influences the model. Incorporating the cooling factor, a more comprehensive cost model and a refined dynamic stall model will also further improve the simulation’s accuracy and robustness.

Novel Technique to Close Stellate Corneal Lacerations.

The study was performed to evaluate and optimize a novel technique to close stellate corneal lacerations in a wet laboratory environment. Twenty-one ex vivo porcine eyes with standardized, experimentally created stellate corneal lacerations were assigned to one of three surgical repair techniques. In Group 1 (n = 9), lacerations were closed with simple interrupted sutures only. In Group 2 (n = 7), a large-radius central purse string was used in addition to simple interrupted sutures. In Group 3 (n = 5), a small-radius central purse string was used in addition to simple interrupted sutures. Wound stability was assessed by determining the intraocular pressure (IOP) at which wound leak occurred. Group 3 eyes demonstrated a mean wound leak IOP of 56.1 mm Hg (range 32-90.3) compared with groups 1 and 2, which demonstrated mean wound leak IOPs of 6.4 mm Hg (range 1.9-19) and 13.3 mm Hg (range 2.8-31), respectively. These differences were highly statistically significant (P<0.002 and P<0.015, respectively, compared with Group 3). The use of a small-radius internal purse-string suture, when combined with simple interrupted sutures, produced a highly effective watertight closure in experimentally created stellate corneal lacerations, significantly outperforming approaches using only interrupted sutures or a large-radius purse string. The use of a small-radius purse-string suture should be considered for clinical use in the repair of stellate corneal lacerations.

Overview of Key Technologies for Wind Energy Applications

Due to the pursuit of economic benefits and the development and damage to the environment, the need to develop new energy sources is increasing day by day. as one of the earliest and most mature new energy generation methods, wind power has received much attention. However, wind power generation system is constrained seriously by the environment because of the random fluctuation of wind power itself. It is easy to cause problems such as low power generation efficiency and fast device loss due to the influence of wind instability. At the same time, it is difficult to store and connect electric energy to the electricity grid.

Clinical outcomes of using operating microscope for alveolar ridge preservation: A randomized controlled trial.

The use of the operating microscope (OM) for extraction and alveolar ridge augmentation (ARP) is increasing due to enhanced magnification and illumination. The primary objective was to compare the wound healing and crestal bone quality after the use of OM and dental loupes (DL) for ARP. Forty non-molar teeth with periapical lesions in need of extraction and ARP from 33 patients were randomly assigned to 2 groups: DL (control) or OM (test). All procedures were performed by 1 surgeon and assessments done by masked examiners. ARP was performed with an allograft and a resorbable collagen membrane. The presence of granulomatous tissue remnants after debridement was recorded. Cone-beam computed tomography (CBCT) and ultrasound (US) scans were taken during the healing phase up to 16-week visits. Bone cores were retrieved from implant osteotomies for histologic analysis. Patient-reported outcome measurements (PROMs) were assessed. All patients completed all study visits except 1 who dropped out before the last visit. After socket debridement, the test group exhibited significantly fewer sites with tissue remnants (p=0.01) and a better healing score at 2-week (p=0.04) and 4-week (p=0.01) time points. There were no significant differences in 12-week crestal bone healing by histology (p=0.1), US (p=0.85), and CBCT healing (p=0.64) at 12weeks, as well as PROMs (p>0.1). Within the limitation of the study, the use of OM for ARP resulted in significantly fewer tissue remnants and favorable early visual wound healing. CBCT and US-derived-crestal bone quality did not show a difference between the 2 groups. Alveolar ridge preservation (ARP) by placing bone particulates in the extraction socket, covered by a wound dressing material, is commonly applied immediately after tooth extraction to reduce jawbone shrinkage in preparation for implant placement later. The jawbone healing varies, depending largely on the ability to remove the etiology, socket features, extent of surgical trauma, and wound stability. Healed jawbone with good quality is favorable for easiness of implant placement and could be related to maintenance of long-term implant health. The surgical microscope with high magnification (up to ∼25×) and co-axial illumination is ideal for assistance in the removal of granulomatous tissue that is believed to interfere with healing, performance of minimally invasive extraction, and stabilization of the wound with meticulous tissue management and fine sutures. This study compared the use of the surgical microscope to dental loupes for ARP in a randomized controlled design. The microscope-assisted ARP is associated with a significantly higher chance of removing granulomatous tissue, favorable early healing, and similar crestal bone quality. Removal of granulomatous tissue is significant for immediate implant placement. This study serves as a model for testing the benefits of the surgical microscope for encouraging early healing in more challenging intraoral surgical procedures.

A Study of Stochastic Low-frequency Variability for Galactic O-type Stars

In order to explore how the ubiquitous stochastic low-frequency (SLF) variability of O-type stars is related to various stellar characteristics, we compiled a sample of 150 O-type stars observed via ground-based spectroscopic surveys, alongside photometric data obtained from the Transiting Exoplanet Survey Satellite (TESS). We analyzed 298 light curves obtained from TESS Sectors 1–65 for the stars in our sample. Leveraging the spectroscopic parameters, we used Bonnsai to determine masses, radii, fractional main-sequence ages, and mass-loss rates for stars of our sample. Subsequently, we identified possible correlations between the fitted parameters of SLF variability and stellar properties. Our analysis unveiled four significant correlations between the amplitude and stellar parameters, including mass, radius, fractional main-sequence ages, and mass-loss rate. For stars with ≳30 M ⊙, we observed a decrease in characteristic frequency and steepness with increasing radius. Finally, we compared various physical processes that may account for the SLF variability with our results. The observed SLF variability may arise from the combined effects of the iron convection zone (FeCZ) and internal gravity waves (IGWs), with IGWs potentially more dominant in the early stages of stellar evolution, and the contribution of FeCZ becoming more significant as stars evolve. Meanwhile, our results indicate that the SLF variability of O-type stars bears certain signatures of the line-driven wind instability and granulation.

Proton Temperature Anisotropy Constraint Associated With Alpha Beam Instability in the Solar Wind

AbstractSolar wind observations in the space of the proton temperature anisotropy versus parallel proton beta always show a distorted rhomboid‐like pattern, where the boundaries of this plot are associated with several instabilities. However, the specific mechanism on the constraint of the proton temperature anisotropy is unclear in the low‐beta plasma. In this work, we study the kinetic instabilities driven by proton temperature anisotropy and alpha beam with the Vlasov theory and investigate the nonlinear evolution of these instabilities with hybrid simulations. We also compare the theoretical and simulation results with Wind observations. The alpha beam with drift velocity leads to a new kind of Alfvén/ion‐cyclotron instability (A/IC instability) in the region of . In the region of and , the nonlinear wave‐particle interaction through the A/IC instability can decelerate alpha beams to and result in the anti‐correlation between and . In the region of and , the nonlinear wave‐particle interaction through the A/IC instability further leads to slight increase of . The present results provide a potential mechanism for regulating the proton temperature anisotropy in the low‐beta plasma with in the solar wind.

Partial-Full-Thickness Tunnel Technique and Supra-Crestal Sling Suture for Treatment of RT2 and RT3 Gingival Recessions: Technical Report with Two Cases.

The purpose of this technical report is to describe a modified tunnel surgical approach and connective tissue graft (CTG) stabilization technique for the treatment of gingival recessions with interproximal clinical attachment loss (ICAL). The partial-full-thickness (PFT) tunnel technique utilizes multiple vestibular incisions to facilitate creation of a split-mucoperiosteal tunnel that enhances tissue passivity and allows for coronal advancement of soft tissue with minimal tension. The supra-crestal sling (SCS) suture engages only the CTG, independent of the overlying tissue and stabilizes the CTG around the buccal and proximal root surfaces. The treatment approach of PFT tunnel preparation and CTG stabilization with the SCS suture was designed to optimize blood supply and maximize wound stability, resulting in complete root coverage with satisfactory clinical outcomes in RT2 and RT3 gingival recession. It is suggested that the PFT tunnel preparation with graft stabilization via the SCS suture has the potential to treat recessions with anatomical limitations associated with ICAL.

Bionic sulfated glycosaminoglycan-based hydrogel inspired by snail mucus promotes diabetic chronic wound healing via regulating macrophage polarization

The treatment of diabetic foot ulcers remains a significant challenge, as their morbidity is increasing while current therapies are expensive and often ineffective. The dried mucus from the snail Achatina fulica promotes diabetic wound healing. Herein, to develop a more controllable and stable wound dressing for diabetic wound treatment, the AFG/StarPEG hydrogel mimicking snail mucus was prepared by covalently coupling of sulfated glycosaminoglycan from A. fulica (AFG) with star-shaped polyethylene glycol (StarPEG) amine. The AFG/StarPEG hydrogel reduced excessive inflammation in wound tissues by decreasing pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and increasing anti-inflammatory cytokines (IL-4 and IL-10). Moreover, it promoted the polarization of macrophages to M2 anti-inflammatory type in diabetic wound. By improving transition of diabetic chronic wound from inflammatory phase to proliferative phase, it promoted angiogenesis, collagen deposition and re-epithelialization, and thus tissue regeneration for wound healing. This work provides a convenient and effective dressing for treating chronic diabetic wound.

Method for Producing Columnar Ice in Laboratory and Its Application

This study presents the design of a small open-circuit wind tunnel for laboratory use and a method for preparing columnar ice. The ice formation process was analyzed in terms of temperature and ice thickness variations under varying environmental temperatures and wind speeds. Observations revealed that as wind speed increased, the grain size of the columnar ice decreased. Key findings include the following: (1) the selection and validation of two cubic arcs for the wind tunnel contraction section, achieving an acceleration ratio of 6.7–6.8 and stable wind speeds of 1–10 m/s; (2) real-time temperature monitoring indicated rapid cooling before freezing and slower cooling post-freezing, with lower ambient temperatures and higher wind speeds accelerating the icing process; (3) the −1/2 power of grain size was found to be positively correlated with wind speed; and (4) the method’s feasibility for studying mechanical properties of polar columnar ice was confirmed. This technique offers a controlled approach for producing columnar ice in the laboratory, facilitating comprehensive research on ice properties and providing a foundation for future studies on the mechanical behavior of ice under windy polar conditions.

Green energy: a modern view in conditions of environmental safety

Expansion of the use of renewable energy sources (RES) became possible due to technical progress in this area, which allowed, first of all, to significantly reduce the cost of electricity production by wind and solar power plants of various types. Since 2000, wind power has developed with an average annual growth rate of more than 21%. In the early years of wind power deployment, Europe was the key region for global wind turbine installations. In 2010, the region accounted for 47 % of global onshore wind turbine deployments. After 2010, other regions, especially China, have seen rapid wind energy development. By 2018, China had overtaken Europe to become the largest onshore wind energy market with nearly one-third of the world's installed capacity. Some experts estimate that onshore wind power installations will need to have an average annual growth rate of more than 7 % over the next three decades. Offshore wind energy technologies allow countries to exploit generally higher and sometimes more stable wind resources, by implementing gigawatt projects near densely populated coastal areas common in many parts of the world. This makes wind power an important addition to the portfolio of low-carbon technologies available to the energy sector in many countries. Green energy, in terms of environmental impact, leads to a more environmentally friendly process. Energy obtained from naturally occurring sources such as wind, sun and water, i.e. renewable energy is better for the environment because energy production does not produce greenhouse gases – gases that enter the atmosphere, trap heat and cause global warming. The main goal of our work is to analyze the experience of large-scale development of renewable energy sources in a number of countries, its impact, including negative ones, on traditional generation and the electricity market, with the development of relevant specific recommendations for overcoming specific challenges and ensuring environmental safety in each country

A short-term wind speed prediction method based on the IDBO-BPNN

Wind energy is known for its uncertainty and volatility, necessitating accurate wind speed prediction for stable wind farm operations. To enhance wind speed prediction accuracy, this study proposes a BP neural network (BPNN) short-term wind speed prediction model based on the Improved Dung Beetle Optimization (IDBO) algorithm. Addressing the issue of local optimization and reduced accuracy in the BPNN optimized by the Dung Beetle Optimization (DBO) algorithm, the circle chaotic mapping is utilized for population initialization to achieve a more uniform initial distribution. The improved sine-cosine algorithm, triangle wandering strategy, and adaptive weight coefficient are then employed to optimize dung beetle positions, balancing global exploration and local development capabilities and improving the algorithm’s search performance. Finally, the improved DBO algorithm optimizes the weights and thresholds of the BPNN, and the IDBO-BPNN prediction model was constructed. Simulation experiments were conducted based on wind speed data from a wind farm in Ohio, USA. The IDBO-BPNN model was compared with other prediction models, and error evaluation indexes were introduced to evaluate the experimental results. The findings demonstrate that the suggested model yields the most accurate predictions and achieves the optimal error evaluation indexes. MAE, MSE, RMSE, NSE and R2 of dataset 1 are 0.42247, 0.28775, 0.53642, 88.8785%, 89.161%, those of dataset 2 are 0.28283, 0.14952, 0.38668, 85.7383%, 86.577%, and those of dataset 3 are 0.45406, 0.39268, 0.62664, 84.3859%, 84.931%. In particular, compared with BPNN model, the five evaluation indexes of the IDBO-BPNN model promoted by 41.53%, 57.38%, 34.71%, 24.91%, and 11.44%, respectively in dataset 3. Therefore, that the proposed IDBO-BPNN model exhibits higher accuracy in short-term wind speed prediction, indicating its feasibility and superiority in the realm of wind energy.

Exergy and exergoeconomic analysis of a hybrid airborne wind and solar energy system for power, liquid nitrogen and carbon dioxide production

Airborne wind energy (AWE) systems have emerged as cost-effective and sustainable solutions that have not yet been coupled with solar technologies and integrated power plants to produce energy and on-demand substances. This study proposes an integrated system driven by an innovative AWE and photovoltaic (PV) hybrid system. This combination can harness stronger and more stable wind energy while decreasing system costs and power intermittency. The proposed system combines seven subsystems, including AWE, PV, air separation unit, oxyfuel power plant, absorption refrigeration, a nitrogen liquefaction process, and Organic Rankine Cycle (ORC) to simultaneously generate power, liquid nitrogen, and liquid carbon dioxide. The hybrid AWE-PV system can generate 10.8 MW power to initiate the system to produce 55 MW power, 127.2 m3/h liquid nitrogen, and 98.4 m3/h liquid carbon dioxide. The exergy analysis has been conducted, showing maximum exergy destruction in heat exchangers, and the total exergy efficiency of the integrated structure reaches 90.21 %. The exergoeconomic analysis illustrates that the maximum capital cost occurs in compressors and turbines with a percentage of 51 % (∼4600 $/h) and 26 % (∼2400 $/h), respectively. This first demonstration of implementing hybrid AWE-PV renewable energy sources in an integrated structure can open new perspectives and avenues toward using AWE and its combination with other renewable energy sources in the future.

Comparative Analysis of Global Onshore and Offshore Wind Energy Characteristics and Potentials

Wind energy, which generates zero emissions, is an environmentally friendly alternative to conventional electricity generation. For this reason, wind energy is a very popular topic, and there are many studies on this subject. Previous studies have often focused on onshore or offshore installations, lacking comprehensive comparisons and often not accounting for technological advancements and their impact on cost and efficiency. This study addresses these gaps by comparing onshore and offshore wind turbines worldwide in terms of installed capacity, levelized cost of electricity (LCOE), total installed cost (TIC), capacity factor (CF), turbine capacity, hub height, and rotor diameter. Results show that onshore wind power capacity constituted 98.49% in 2010, 97.23% in 2015, and 92.9% in 2022 of the world’s total cumulative installed wind power capacity. Offshore wind capacity has increased yearly due to advantages like stronger, more stable winds and easier installation of large turbine components. LCOE for onshore wind farms decreased from 0.1021 USD/kWh in 2010 to 0.0331 USD/kWh in 2021, while offshore LCOE decreased from 0.1879 USD/kWh in 2010 to 0.0752 USD/kWh in 2021. By 2050, wind energy will contribute to 35% of the global electricity production. This study overcomes previous limitations by providing a comprehensive and updated comparison that incorporates recent technological advancements and market trends to better inform future energy policies and investments.

Coexistence of Antisunward and Sunward Ion Cyclotron Waves in the Near-Sun Solar Wind: Excitation by the Proton Cyclotron Instability

Based on observations from the Parker Solar Probe in the near-Sun solar wind, this study identifies an ion-scale wave event characterized by two distinct frequency bands. The lower-band waves exhibit right-hand polarization, while the upper-band waves have left-hand polarization. Alongside these waves, there are clear indications of the existence of both proton core and beam components, with the perpendicular temperature being higher than the parallel temperature in the measured proton velocity distribution functions (VDFs). Utilizing the plasma parameters derived from typical proton VDFs, instability analyses are conducted to investigate the mode nature of the observed waves and their excitation mechanism. The lower-band waves are identified as sunward ion cyclotron waves (ICWs), generated through the proton beam cyclotron instability; the upper-band waves are recognized as antisunward ICWs, induced by the proton core cyclotron instability. This study provides the first direct observational evidence confirming the presence of counterpropagating ICWs and proton cyclotron instability in the solar wind.

The wind-solar hybrid energy could serve as a stable power source at multiple time scale in China mainland

The instability of wind and solar power hinders their penetration into electrical transmission networks. Hybrid wind-solar power generation can mitigate the instability of wind or solar power. However, research on complementary methods and the temporal distribution of wind and solar energies remains insufficient. In this study, well-validated and used high-resolution reanalysis data were used to explore the complementarity between wind and solar power on multiple time scales across China mainland. Researchers have found that wind and solar energies are strongly complementary from seasonal to hourly time scales. Wind-solar hybrid power generation can increase the availability of renewable energy by 15%–25 %, and a continuous renewable power supply can be achieved during daytime hours. In addition, the authors found that the complementary strength between wind and solar power could be enhanced by adjusting their proportions. This study highlights that hybrid wind-solar systems can provide a stable energy source. The complementary deployment of wind and solar energies should be considered in future applications.

Self-Improving Online Storage Control for Stable Wind Power Commitment

Self-Improving Online Storage Control for Stable Wind Power Commitment

Daytime and night-time patterns in PM2.5 concentrations over Palembang City of Indonesia using MERRA-2 reanalysis data

ABSTRACT Palembang has sustained heavy haze pollution events that are related to decrease public health quality. Because ground-based PM2.5 observation in the city has some limitations, such as spatial and temporal coverages. Thus, in this study, we applied the potential of using the surface mass concentration PM2.5 data acquired by the MERRA-2 satellite to predict daytime and night-time PM2.5 levels during heavy haze events in Palembang City. Results of the study revealed that the highest PM2.5 level was about 160 µg/m3 at 02:00 (night-time), while the lowest PM2.5 level was about 50 µg/m3 at 14:00 (daytime). Spatiotemporal variation of PM2.5 over the study area showed that more than half of the area showed PM2.5 above 90 µg/m3 at night. Stable wind conditions (2 m/s) and air temperature (29°C), and relative humidity (74%) in the study area have contributed to particulate matter accumulation. The study concluded that PM2.5 acquired by the MERRA-2 satellite could provide a new reliable source for assessing severe air pollution events.

Prediction of ultimate tensions in mooring lines for a floating offshore wind turbine considering extreme gusts

The design of mooring line parameter for a floating offshore wind turbine (FOWT) should consider the ultimate limit state. Typhoons should be considered as a threatening condition for mooring design, and the characteristics of transient changing wind should be studied. Currently, few extreme value predictions consider gust features, and extreme mooring tensions may be underestimated in practical FOWT design. We conducted the simulations of the 5 MW wind turbine from the National Renewable Energy Laboratory (NREL) in the environmental conditions of extreme gusts, waves, and currents. Extreme gusts were found to cause dramatic increases in mooring tensions under 100-year typhoon conditions. The average conditional exceedance rate (ACER) method is used to predict extreme mooring tensions. The impacts of simulation duration and sample size on the prediction results are then discussed. The results show that in extreme gust conditions, the tail data of the average conditional exceedance rate of mooring tension presents a different extrapolation trend from stable wind conditions. Short-term predicted values in gust conditions are 14–20% larger than those in stable wind conditions. The research shows the necessity of considering threatening gust conditions in the ultimate limit state design of mooring system of FOWT.