Extreme Wind Research Articles

Assessing South Indian Ocean tropical cyclone characteristics in HighResMIP simulations

AbstractSeveral damaging tropical cyclones (TCs) have occurred recently over the South Indian Ocean (SIO) region, causing enormous social and economic losses. Yet, while many studies have examined SIO TC characteristics using observations and reanalysis, only a few have assessed these characteristics specifically for this region in climate models, and fewer have investigated their projections under climate change. Here we do this for a historical (1980–2010) and future (2020–2050) period, using multimodel simulations from the High Resolution Model Intercomparison Project, as well as examine biases in the historical period relative to a reanalysis (ERA5). The models have horizontal resolutions of 25–50 km, which has enabled an improved ability to represent tropical cyclones globally in previous studies. TempestExtremes software is employed to detect tropical storm and cyclone tracks. In cases where TempestExtremes cannot be applied due to a lack of requisite variables in a dataset, we instead examine extreme wind speeds in that dataset. For the historical period, we find considerable variation in model biases compared to ERA5, which itself exhibits realistic spatial patterns of tracks and their monthly distribution. Models do at least agree on positive biases in track frequency east of Madagascar and somewhat in the Mozambique Channel. However, the models and ERA5 only produce Category 3 tropical cyclones at best. Wind speeds for 25 km resolution models have much larger positive biases than for 50 km ones, suggesting the former can simulate even higher‐category tropical cyclones. Considerable intermodel variation is also found in track changes between the future and historical periods. No systematic intercategory pattern of change exists, and low signal‐to‐noise may obscure any such patterns in the limited timespan of available data. Thus, no meaningful conclusions can be drawn regarding changes in track intensity. Nevertheless, track frequency broadly decreases across models for the region, as does accumulated cyclone energy. An east‐to‐west shift in track location from east of Madagascar toward the Mozambique Channel is also implied by track frequency and wind speed changes. Our findings provide information to potentially improve storm resiliency in this vulnerable region.

The Efficacy of Modified Ilizarov Distraction-Tension Device on Limb Wound Difficult to Cover with Skin Flaps.

Closure of complex limb wounds poses challenges and requires innovative approaches. This research aimed to evaluate the effectiveness of a modified distraction-tension device using Ilizarov external fixation for wound closure in challenging cases. A retrospective analysis was conducted on 43 patients with extremity wounds that were difficult to cover with skin flaps between January 2019 and December 2022. Tension-relieving traction was applied using the Ilizarovexternal fixator apparatus, tailored to individual wound characteristics. Three types of wire-pin connections were used in this study. The distraction begins on the third postoperative day, with a speed of 0.5mm/d. Clinical wound healing scores were evaluated at 5 and 30 days postoperatively. Complications were documented following the Paley classification system. Traction using modified Ilizarovexternal fixation promoted a significant reduction in wound size. The mean traction period was 11.2 ± 7.3 days, and the mean healing duration was 17.0 ± 3.7 days. The clinical wound healing score improved from 3.7 ± 2.9 at 5 days to 1.7 ± 0.7 at 30 days postoperatively (p < 0.05). Complications were minimal, with no significant obstacles or sequelae observed. Direct closure healing was achieved in 21 cases, skin graft healing in 13 cases, and suture healing in 9 cases. No recurrences were reported. Using Paley's classified complications, there were 17 problems, 9 obstacles, and 0 sequelae. The Ilizarov tension-relieving traction shows promise in facilitating wound closure that is challenging to manage with skin flaps. The modified three types of pin-skin connection configuration could satisfy various types of wound closure.

Effectiveness of negative pressure wound therapy as a fixator in split thickness skin graft applied diabetic patients: evaluation of 25 cases

Objective: Microangiopathies expose diabetic patients to lower extremity wounds at certain stages of their lives. Split-thickness skin grafting (STSG) has an important place in the surgical treatment of such wounds. The aim of the present study is to evaluate the effects of negative pressure wound therapy (NPWT) on STSG survival. Methods: A total of 25 diabetic patients (M = 20, F = 5) with acute or chronic lower extremity open wounds were included in the study. All patients underwent wound debridement under regional anesthesia. STSG was applied after wound debridement. NPWT was applied to STSG to increase graft survival. Results: The hospitalization times of the patients ranged from 1 to 2 weeks. The mean follow-up period of the patients was 6 months. All wounds healed on the 14th postoperative day. There was no recurrence in the 6-month follow-up period. Conclusion: We objectively demonstrated the positive effects of NPWT application on STSG and graft survival.

Surface Charging of the Jupiter Icy Moons Explorer (JUICE) Spacecraft in the Solar Wind at 1 AU

AbstractThis article presents the first study of the interaction between the Jupiter Icy Moons Explorer (JUICE) spacecraft and the solar wind environment at 1 AU. The state‐of‐the‐art software Spacecraft Plasma Interaction Software was used to simulate the surface charging of the spacecraft and the altered particle environment around the spacecraft. The simulations show that for a typical solar wind environment the spacecraft will charge to around 6 V, with the different dielectric parts of the spacecraft charging to potentials from around −36 to 8 V. For the studied extreme solar wind environment, similar to the environment found in the sheath region inside the shock front of an Interplanetary Coronal Mass Ejection, the surface potential of the spacecraft is lower due to the increased accumulation of electrons. The spacecraft will charge to around 3 V, with the different dielectric surfaces charging from around −45 to 9 V. We also show how the interaction between the spacecraft and its environment alters the ion and electron particle environment around the spacecraft. This study is the first step toward developing correction techniques for the impact that the interaction between the JUICE spacecraft and its environment has on the JUICE charged particle and field measurements.

Modeling and observations of North Atlantic cyclones: Implications for U.S. Offshore wind energy

To meet the Biden-Harris administration's goal of deploying 30 GW of offshore wind power by 2030 and 110 GW by 2050, expansion of wind energy into U.S. territorial waters prone to tropical cyclones (TCs) and extratropical cyclones (ETCs) is essential. This requires a deeper understanding of cyclone-related risks and the development of robust, resilient offshore wind energy systems. This paper provides a comprehensive review of state-of-the-science measurement and modeling capabilities for studying TCs and ETCs, and their impacts across various spatial and temporal scales. We explore measurement capabilities for environments influenced by TCs and ETCs, including near-surface and vertical profiles of critical variables that characterize these cyclones. The capabilities and limitations of Earth system and mesoscale models are assessed for their effectiveness in capturing atmosphere–ocean–wave interactions that influence TC/ETC-induced risks under a changing climate. Additionally, we discuss microscale modeling capabilities designed to bridge scale gaps from the weather scale (a few kilometers) to the turbine scale (dozens to a few meters). We also review machine learning (ML)-based, data-driven models for simulating TC/ETC events at both weather and wind turbine scales. Special attention is given to extreme metocean conditions like extreme wind gusts, rapid wind direction changes, and high waves, which pose threats to offshore wind energy infrastructure. Finally, the paper outlines the research challenges and future directions needed to enhance the resilience and design of next-generation offshore wind turbines against extreme weather conditions.

철도산업과 기후변화대응

The railroad industry is the best means of transportation to respond to climate change, as it is more energy efficient than the automobile and aircraft industries and emits about six times less greenhouse gases. As of 2018, the transportation sector of railroads emits 2.6% of greenhouse gases, but greenhouse gases should be reduced by converting diesel locomotives to new and renewable energy locomotives and electric locomotives. However, the Framework Act on the Railway Industry, the Railroad Safety Act, the Railroad Construction Act, and the Railroad Business Act do not have legal and institutional mechanisms to respond to climate change or adapt to the climate crisis. Review the legislation and precedents of France and the United States to seek implications for Korea. The Framework Act on the Railway Industry shall establish and implement the national freight and passenger transport sharing rate and the greenhouse gas reduction target, and shall be improved to include matters on climate change and response to the climate crisis in the national policies and basic plans. The Railway Construction Act should also monitor the effects of climate change, such as extreme heat waves, extreme cold waves, extreme strong winds (types), extreme floods, and extreme wildfires, analyze the cost-benefit analysis of adverse effects on railway infrastructure to build them in advance, and maintain them to improve the quality of railway infrastructure, and include climate change response and adaptation to the climate crisis in the railway network plan. The Railway Business Act and the Railroad Safety Act should be revised to ban the operation of diesel locomotives in stages, such as California and the United Kingdom, to raise funds for the conversion of diesel locomotives to environment-friendly locomotives, report their status to the Minister of Land, Infrastructure and Transport, and stipulate that diesel locomotives cannot be idled for more than 30 minutes. Finally, railway stations and structures should be installed with geothermal power plants and solar power plants, and certified as carbon-zero buildings.

Evaluation of future wind climate over the Eastern Mediterranean Sea

The aim of this study is to evaluate wind climate characteristics in the Eastern Mediterranean Sea until the end of the 21st century using the wind fields simulated by the EURO-CORDEX Regional Climate Models (RCM), namely the Rossby Centre regional atmospheric model (version RCA4). Long-term averages, long-term trends, and long-term variability in wind characteristics under two Representative Concentration Pathway (RCP 4.5 and 8.5) scenarios were assessed for two future periods: the near future for the years 2021–2060 and the middle future for the years 2061–2100. Relative to the historical period, the most remarkable changes in the mean wind speeds were projected under the RCP 8.5 scenario in the middle future in the central and southern Aegean Sea (exceeding 5 % increase) and in the eastern and northern Levantine basin (up to 5 % decrease), compatible with the definition of the climate scenarios as the RCP8.5 scenario assumes a rising radiative forcing until 2100. The changes in extreme wind characteristics are more noteworthy in agreement with the indicators of climate change (i.e., an increase in the intensity and the frequency of extreme events). 100-year return period wind speed increases by about 29 % in the western Levantine basin under the RCP 8.5 scenario while the most drastic decrease in 100-year extreme wind speed was found in the central Levantine basin with a reduction of exceeding −29 % for the middle future period under the RCP 8.5 scenario. These decreasing and increasing behaviors in extreme wind speeds are expected in the study area as the Mediterranean is affected by many climate systems.

Evaluation of Seasonal Prediction of Extreme Wind Resource Potential over China Based on a Dynamic Prediction System SIDRI-ESS V1.0

Wind resources play a pivotal role in building sustainable energy systems, crucial for mitigating and adapting to climate change. With the increasing frequency of extreme events under global warming, effective prediction of extreme wind resource potential can improve the safety of wind farms and other infrastructure, while optimizing resource allocation and emergency response plans. In this study, we evaluate the seasonal prediction skill for summer extreme wind events over China using a 20-year hindcast dataset generated by a dynamical seamless prediction system designed by Shanghai Investigation, Design and Research Institute Co., Ltd. (Shanghai, China) (SIDRI-ESS V1.0). Firstly, the hindcast effectively simulates the spatial distribution of summer extreme wind speed thresholds, even though it tends to overestimate the thresholds in most regions. Secondly, high prediction skills, measured by temporal correlation coefficient (TCC) and normalized root mean square error (nRMSE), are observed in northeast China, central east China, southeast China, and the Tibetan Plateau (TCC is about 0.5 and the nRMSE is below 0.9 in these regions). The highest skills emerge in southeast China with a maximum TCC greater than 0.7, and effective prediction skill can extend up to a 5-month lead time. Ensemble prediction significantly enhances predictive skill and reduces uncertainty, with 24 ensemble members being sufficient to saturate TCC and 12–16 members for nRMSE in most key regions and lead times. Furthermore, we show that the prediction skill for extreme wind counts is strongly related to the prediction skill for summer mean wind speeds, particularly in southeast China. Overall, SIDRI-ESS V1.0 shows promising performance in predicting extreme winds and has great potential to provide services to the wind industry. It can effectively help to optimize wind farm operating strategies and improve power generation efficiency. However, further improvements are needed, particularly in areas where prediction skills for extreme winds are influenced by smaller-scale weather phenomena and areas with complex underlying surfaces and climate characteristics.

The impact of Climate Change on extreme winds over northern Europe according to CMIP6

The impact of Climate Change on extreme winds over northern Europe according to CMIP6

Lower Extremity Traumatic Wound Management: Relative Significance of Negative Pressure Wound Therapy in the Orthopedic Setting.

Significance: Lower extremity traumatic wounds are associated with numerous perioperative challenges. Their etiologies determine the characteristics and extent of the injury. The timing of subsequent surgical intervention and wound healing optimization after lower extremity trauma are integral to successful perioperative lower extremity wound management. Recent Advances: Managing trauma to the lower extremities uses a multidisciplinary surgical approach. The objective of this review is to summarize lower limb trauma assessment, advancements in lower extremity trauma management, and the clinical applications of advanced wound care in lower limb traumatic wounds. The advent of lower limb reconstruction and the development of advanced wound care modalities have helped to improve the management of these complex injuries. Critical Issues: The extensive involvement of bone, soft tissues, nerves, and blood vessels of severe lower extremity trauma wounds presents a challenge for clinicians in both the acute care setting and during patient rehabilitation. If not properly managed, these injuries may be subject to a decline in limb function and may possibly result in limb loss. To reveal developing limb-threatening conditions, serial examinations should be performed. Future Directions: The majority of lower limb traumatic wound will benefit from the perioperative administration of an appropriate negative pressure wound therapy (NPWT)-based system, which can help to promote granulation tissue and remove wound exudate before definitive closure and/or reconstruction. NPWT should be included as an important adjunct in the surgical management of lower limb traumatic wounds.

Classification and identification of extreme wind events by CNNs based on Shapelets and improved GASF-GADF

In this manuscript, we propose an automatic classification and recognition method for extreme wind events based on Convolutional Neural Networks (CNNs) and combining the Shapelet Transform (ST) algorithm with the improved Gramian Angular Summation Field - Gramian Angular Difference Field (GASF-GADF) 2D images construction format. First, a CNN model suitable for wind speed time series 2D images classification and recognition among five mainstream CNNs (ResNet-50, ShuffleNet0.5 × , DenseNet-121, EfficientNet-B2, and EfficientNetV2-S) is preferred based on the basic Gramian Angular Field (GAF) method; then, the improved GASF-GADF images construction format is proposed, and the optimal CNN is used to compare the classification and recognition results based on other three image conversion methods: Markov Transition Field (MTF), GASF, GADF. Last, it is proposed to utilize the ST algorithm to extract the feature subsequence Shapelets of wind speed time series to further improve the classification and recognition effect on extreme wind events. The effectiveness and applicability of the proposed method were verified through three extreme wind event datasets in this paper.The results show that the combination of Shapelets and the improved GASF-GADF images transformation method proposed in this paper can effectively enhance the classification and recognition of extreme wind events by CNNs. Among them, EfficientNetV2-S combined with the method proposed in this paper achieves 99.50%, 99.50% and 97.50% recognition Accuracy for thunderstorm, gust front and typhoon, respectively. Meanwhile, it still has good robustness for extreme wind events disturbed by noise.

Objective identification of meteorological fronts and climatologies from ERA-Interim and ERA5

Abstract. Meteorological fronts are important due to their associated surface impacts, including extreme precipitation and extreme winds. Objective identification of fronts is therefore of interest in both operational weather prediction and research settings. The aim of this study is to produce a front identification algorithm based on earlier studies that is portable and scalable to different resolution datasets. We have made a number of changes to an earlier objective front identification algorithm, applied these to reanalysis datasets, and present the improvements associated with these changes. First, we show that a change in the order of operations yields smoother fronts with fewer breaks. Next, we propose the selection of the front identification thresholds in terms of climatological quantiles of the threshold fields. This allows for comparison between datasets of differing resolutions. Finally, we include a number of numerical improvements in the implementation of the algorithm and better handling of short fronts, which yield further benefits in the smoothness and number of breaks. This updated version of the algorithm has been made fully portable and scalable to different datasets in order to enable future climatological studies of fronts and their impacts.

Underestimation of strong wind speeds offshore in ERA5: evidence, discussion and correction

Abstract. Offshore wind power plants have become an important element of the European electrical grid. Studies of metocean site conditions (wind, sea state, currents, water levels) form a key input to the design of these large infrastructure projects. Such studies rely heavily on reanalysis datasets which provide decades-long model time series over large areas. In turn, these time series are used for assessing wind, water levels and wave conditions and are thereby key inputs to design activities such as calculations of fatigue loads and extreme loads and platform elevations. In this article, we address a known deficiency of one these reanalysis datasets, ERA5, namely that it underestimates strong wind speeds offshore. If left uncorrected, this poses a design risk (high and extreme wind, waves and water level conditions are underestimated). Firstly, comparisons are made against CFSR/CFSv2 reanalyses as well as high-quality wind-energy-specific in situ measurements from floating lidar systems. Then, the ERA5 surface drag formulation and its sea state dependency are analysed in detail, the conditions of the bias identified, and a correction method is suggested. The article concludes with proposing practical and simple ways to incorporate publicly available, high-quality wind energy measurement datasets in air–sea interaction studies alongside legacy measurements such as met buoys.

Effects of extreme stratospheric polar vortex events on near-surface wind gusts across Europe

Abstract Extreme stratospheric polar vortex (SPV) events can influence winter tropospheric circulation for up to 60 d. Their impacts on air temperature have been extensively studied recently. However, there is a research gap in their effects on wind speeds and its extremes. This study aims to evaluate, for the first time, the impacts of such extreme SPV events on observed and modelled near-surface wind gusts across Europe. We have analysed wind gust data coming from: station-based observations (for the Iberian Peninsula and Scandinavia), the ERA5 reanalysis and the SEAS5 and GloSea6 seasonal forecasting systems. We assess their similarities in reproducing 4 parameters of their corresponding distributions: median, standard deviation, skewness and kurtosis. For all these datasets, the results indicate that extreme positive SPV events are followed by negative wind gust anomalies in Southern Europe and positive in Northern Europe. Whereas, negative SPV events (such as Sudden Stratospheric Warmings) have positive gust anomalies in Southern Europe and negative in the north. A central region shows negligible anomalies in both cases. This highlights the ability of SPV as a predictor for short-medium-term forecasting of extreme wind events, which would have direct applications to many socioeconomic and environmental issues such as the estimation of wind-power generation.

Stopping the bleed when tourniquets cannot: a technique for Foley catheter balloon compression in trauma.

Hemorrhage is a leading cause of death in trauma. Prehospital hemorrhage control techniques include tourniquet application for extremity wounds and direct compression; however, tourniquets are not effective in anatomic junctions, and direct compression is highly operator dependent. Balloon catheter compression has been employed previously in trauma care, but its use has been confined to the operating room and restricted to specific anatomic injuries. In a single-center retrospective review, we describe a technique for balloon catheter compression for hemorrhage control that can be employed across the continuum of trauma care, from the prehospital setting to the trauma bay, the operating room, and postoperative period. Of 18,303 trauma patients in Venezuela, 45% of the 1757 patients with vascular injuries received Foley catheter compression for hemorrhage control. Of these catheters, the majority (75%) were placed in the emergency department, 5% in the prehospital setting, and 20% in the operating room. Over half (53.2%) of the balloon catheters were placed for hemorrhage control in non-compressible anatomic junctions. Foley catheter balloon compression is a useful addition to a provider's arsenal of hemorrhage control techniques, as it is effective in anatomic junctions, preserves collateral circulation through focused compression, and requires minimal active physical attention to maintain hemostasis.

Evolution characteristics and mechanism of meso-γ-scale vortex in an atypical bow echo in the North China Plain

On June 25, 2020, an atypical bow echo (ATBE) accompanied by a meso-γ-scale vortex (MV) incurred the strongest gust (41.4 m s−1) recorded since 1957 in the North China Plain. In this article, we investigate the evolution characteristics of MV and its mechanism for the extreme wind by using the observation data of Doppler weather radar and automatic weather stations as well as the four-dimensional Variational Doppler Radar Analysis System (VDRAS). The results show that the MV in this process was initially born at a height of 0.9–2.4 km, and the contracting and stretching vertical vortex rapidly descended to surface from the 2.0 km height with the rotation speed increasing rapidly. Six minutes later, the extreme wind occurred. The generation mechanism of the MV is that, under the strong vertical wind shear and downdraft in the lower troposphere, the vertical vortex tube of MV was transformed from the horizontal vortex tube generated in the zone of perturbation temperature gradient. The influence mechanism of MV on the extreme wind is that, as the MV continued to intensify and extend downward, a negative perturbation low-pressure center formed in the lower troposphere near the MV. Meanwhile, the descending rear-inflow jet (RIJ) was blocked by the prefrontal upward motion and a positive perturbation high-pressure center formed at around 1 km height. The violent positive-negative couplets of perturbation pressure gradient produced a downward nonhydrostatic perturbation pressure gradient force (NPPGF) that further intensified the vertical downward velocity. In addition to the strong downdraft velocity, the Coriolis force also enhanced the formation of the extreme wind through the action of ageostrophic winds. Besides, this paper also compares the mechanism of this process with that of a typical bow echo MV and the extreme wind it affected.

Deep and Superficial Debridement Techniques in Lower Extremity Split-thickness Skin Grafting.

Patients with nonhealing lower extremity (LE) wounds often require a split-thickness skin graft (STSG) for closure. Nonviable tissue must be debrided before STSG inset. Our study aimed to compare differences in debridement depth on STSG outcomes. Chronic, atraumatic LE wounds receiving STSG from December 2014 to December 2022 at a single institution were reviewed. Demographics, wound characteristics, operative details, and outcomes were collected. Superficially debrided wounds were compared with wounds receiving deep debridement (DD), defined by debriding to the level of white tissue underlying the granulation tissue. Subanalysis was performed on wounds that had a negative and positive postdebridement culture. Primary outcome was graft failure. Overall, 244 wounds in 168 patients were identified. In total, 158 (64.8%) wounds were superficially debrided and 86 (35.3%) received DD. The cohort had a median Charlson Comorbidity Index of 4 [interquartile range (IQR): 3]. Diabetes (56.6%) and peripheral artery disease (36.9%) were prevalent. The only statically significant demographic difference between groups was congestive heart failure (SD: 14.9% versus DD: 3.0%, P = 0.017). Wound size, depth, and all microbiology results were similar between groups. Postoperatively, the DD group demonstrated significantly less graft failure (10.5% versus 22.2%, P = 0.023). In a multivariate regression, DD was independently associated with lower odds of graft failure (OR: 0.0; CI, 0.0-0.8; P = 0.034). Sub-analysis of graft failure supported this finding in culture-positive wounds (DD: 7.6% versus DD: 22.1%, P = 0.018) but not in culture-negative wounds (13.6% versus 22.2%, P = 0.507). The DD technique demonstrates improved outcomes in chronic, culture-positive LE wounds receiving STSG.

Uncertainty of typhoon extreme wind speeds in Hong Kong integrating the effects of climate change

Uncertainty of typhoon extreme wind speeds in Hong Kong integrating the effects of climate change

Large-scale off-grid wind power hydrogen production multi-tank combination operation law and scheduling strategy taking into account alkaline electrolyzer characteristics

This paper proposes a multi-electrolyzer switching scheduling strategy based on the Pelican Optimization Algorithm (POA) to enhance the efficiency of large-scale wind power hydrogen production systems. To validate the effectiveness of the proposed strategy, we analyzed wind power data from three typical days in northern Hebei, China, with a 2.5 MW wind turbine output. We designed three strategies for comparative analysis: a simple start-stop strategy, a rule-based multi-electrolyzer switching strategy, and a POA-based multi-electrolyzer switching strategy. The study results demonstrate that the POA-based strategy exhibits higher hydrogen production efficiency and system stability under various wind conditions. Particularly, in extreme wind scenarios, this strategy significantly reduces the start-stop cycles of electrolyzers, thereby lowering operational costs and improving overall system performance. The main contribution of this study lies in the novel optimization algorithm and its validation through real-world data, demonstrating its effectiveness in large-scale wind power hydrogen production systems. Our findings provide new insights for enhancing the utilization of renewable energy and the economics of hydrogen production systems.

Joint probabilistic modeling of extreme wind-wave conditions under typhoon impact and applications to extreme response analysis of floating offshore wind turbines

The joint probabilistic modeling of extreme wind and wave conditions under typhoon impact is a critical task for extreme response analysis of floating offshore wind turbines (FOWTs) deployed in typhoon-prone areas. However, wind and wave observations under typhoon impact are quite limited, which poses great challenges to the probabilistic modeling task. Although some sophisticated programs can be employed to simulate typhoon-induced wave fields, they suffer from unbearable computational burdens. To improve the accuracy and efficiency of joint probabilistic modeling of extreme wind and wave conditions under typhoon impact, an approach that synthesizes the typhoon hazard analysis method and copula-based conditional modeling method is proposed in the present study. The proposed joint distribution model is expressed as the product of the distribution of extreme wind speed and the conditional distribution of significant wave height. The distribution of extreme wind speed is estimated through the typhoon hazard analysis method, and the conditional distribution of significant wave height is modeled by the copula-based method. The effectiveness of the proposed method is verified by comparing with observation data. Applications of the proposed method to extreme response analysis of FOWTs are illustrated as well.