气体流量和喷嘴直径对鼓泡塔内气泡大小和形状分布的影响

通过高速摄影结合图像处理算法,研究气体流量和喷嘴直径对气泡尺寸和纵横比分布的影响。结果表明,在所有喷嘴直径下,气泡当量直径的概率密度呈现双峰分布,其中第一个峰值接近直径为1.5~2 mm的小气泡区域,另一个峰值位于较大的气泡区域。将气体流量从0.1 L/min增加到0.2 L/min会导致大气泡的概率密度更高,表明气泡聚并现象普遍存在。当气体流量增加至1.2L/min时,峰值对应的气泡直径变小,并且气泡破裂占主导地位。对于直径为1~2 mm的气泡,形状受气体流量的影响较小,而3~9 mm的气泡在所有气体流量下气泡纵横比概率密度分布的峰值均位于纵横比E=0.5处。Iguchi和Chihara提出的模型能更好地预测气泡脱离直径随气体流量的增大的变化。

Conventional Geothermal Systems and Unconventional Geothermal Developments: An Overview

This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. Medium-temperature (MT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at <7 Km depth (Enhanced Geothermal Systems (EGS), drilling below brittle-ductile transition zones and under geothermal fields), or by the Oil & Gas industry (Advanced Geothermal Systems, heat recovery from hydrocarbon wells or reservoirs, Superhot Rock Geothermal, and millimeter-wave drilling down to 20 Km). Their primary aim is electricity generation, relying on closed-loops, but EGS uses fractures for heat exchange with earthquake risks during fracking. Unconventional approaches could be everywhere, with shallow geothermal already functional. The deeper and hotter unconventional alternatives are still experimental, overcoming costs and technological challenges to become fully commercial. Meanwhile, the conventional geothermal resources remain the most proven opportunities for investments and development.

Microscopic Analysis of Cementitious Sand and Gravel Damming Materia

The mechanical properties of cementitious sand and gravel damming material have been experimentally determined by means of microscopic SEM(Scanning Electron Microscopy)image analysis.The results show that the combination of fly ash and water can fill the voids in cemented sand and gravel test blocks because of the presence of hydrated calcium silicate and other substances;thereby,the compactness and mechanical properties of these materials can be greatly improved.For every 10 kg/m^(3) increase in the amount of cementitious material,the density increases by about 2%,and the water content decreases by 0.2%.The amount of cementitious material used in the sand and gravel in these tests was 80-110 kg/m^(3),the water-binder ratio was 1-1.50.Moreover,the splitting tensile strength was 1/10 of the compressive strength,and the maximum strength was 7.42 MPa at 90 d.The optimal mix ratio has been found to be 50 kg of cement,60 kg of fly ash and 120 kg of water(C50F60W120).The related dry density was 2.6 g/cm^(3),the water content was 6%,and the water-binder ratio was 1.09.

Natural Disaster Risk Monitoring for Immovable Cultural Relics Based on Digital Twin

Natural disaster risk monitoring is an important task for disaster prevention and reduction.In the case of immovable cultural relics,however,the feedback mechanism,risk factors,monitoring logic,and monitoring indicators of natural disaster risk monitoring are complex.How to achieve intelligent perception and monitoring of natural disaster risk for immovable cultural relics has always been a focus and a challenge for researchers.Based on the analysis of the concepts and issues related to the natural disaster risk of immovable cultural relics,this paper proposes a framework for natural disaster risk monitoring for immovable cultural relics based on the digital twin.This framework focuses on risk monitoring,including the physical entities of natural disaster risk for immovable cultural relics,monitoring indicators,and virtual entity construction.A platform for monitoring the natural disaster risk of immovable cultural relics is proposed.Using the Puzhou Ancient City Site as a test bed,the proposed concept can be used for monitoring the natural disaster risk of immovable cultural relics at different scales.

Aspirations on the Bright Side of Humanity: It is Time to Translate Aspirations Into Actions With Establishing the Government of Earth

The thesis of this paper is that the digital noosphere of the World Wide Web and its users,the borderless move of virtually all resources of the planet,and the consequent globalization of most aspects of national politics,economy,and culture,along with the increasing difficulty of controlling the related high-tech military conflicts,human-made environmental crises,and the abnormal migrations of abused people now make it inevitable to leave behind the competitive international chaos rooted in humankind’s animal past and turn to the cooperative social spirit recommended by Aristotle,Lao Tzu,Jesus,Dante,H.G.Wells,Martin Luther King Jr.,John Lennon,Nicholas Hagger,and others to finally translate their aspirations into actions via establishing the Government of Earth for the decent and free.The paper presents a five-step,15-year,~$25B plan to start this process.That this plan has nothing to do with the Godless work of secret societies,the authoritarian urges of renewed fascism or the political absurdities of Marxism-Leninism it is relayed by the envisioned Intercontinental Education System of the outlined Government of Earth to teach every child on the planet-via a new community of digitally linked extraordinary teachers-for the beauty of lifelong learning,tolerance,duty,honor,free cooperation,and artful communication for divine missions.

Radiotherapy for hyoid bone metastasis from lung adenocarcinoma:A case report

BACKGROUND Metastasis to the hyoid bone is an exceptionally rare occurrence,with documented cases limited to breast,liver,colon,skin,lung,and prostate cancers.This report highlights an unusual case involving the metastasis of lung adenocarcinoma to the hyoid bone,accompanied by a distinctive headache.Previous documentation involved surgical resection of the hyoid mass.We present a case displaying the benefits of palliative radiotherapy.CASE SUMMARY A 72-year-old non-smoking,non-alcoholic woman,initially under investigation for a year-long elevation in absolute lymphocyte count,presented with a monthlong history of intermittent throat pain.Despite negative findings in gastroenterological and otolaryngologic examinations,a contrast-enhanced chest computed tomography scan revealed a mediastinal mass and questionable soft tissue thickening in her left anterolateral neck.Subsequent imaging and biopsies confirmed the presence of lung adenocarcinoma metastasis to the hyoid bone.The patient was treated with platinum-based chemo-immunotherapy along with pembrolizumab.Ultimately,the lung cancer was unresponsive.Our patient opted for palliative radiation therapy instead of surgical resection to address her throat pain.As a result,her throat pain was alleviated,and it also incidentally resolved her chronic headaches.This is the second documented case of lung adenocarcinoma metastasizing to the hyoid bone.CONCLUSION Palliative radiotherapy may add to the quality of life in symptomatic patients with cancer metastatic to the hyoid bone.

Distributed Resource Allocation in Dispersed Computing Environment Based on UAV Track Inspection in Urban Rail Transit

With the rapid development of urban rail transit,the existing track detection has some problems such as low efficiency and insufficient detection coverage,so an intelligent and automatic track detectionmethod based onUAV is urgently needed to avoid major safety accidents.At the same time,the geographical distribution of IoT devices results in the inefficient use of the significant computing potential held by a large number of devices.As a result,the Dispersed Computing(DCOMP)architecture enables collaborative computing between devices in the Internet of Everything(IoE),promotes low-latency and efficient cross-wide applications,and meets users’growing needs for computing performance and service quality.This paper focuses on examining the resource allocation challenge within a dispersed computing environment that utilizes UAV inspection tracks.Furthermore,the system takes into account both resource constraints and computational constraints and transforms the optimization problem into an energy minimization problem with computational constraints.The Markov Decision Process(MDP)model is employed to capture the connection between the dispersed computing resource allocation strategy and the system environment.Subsequently,a method based on Double Deep Q-Network(DDQN)is introduced to derive the optimal policy.Simultaneously,an experience replay mechanism is implemented to tackle the issue of increasing dimensionality.The experimental simulations validate the efficacy of the method across various scenarios.

Extraction of tectonic imprints using geospatial techniques:Evidence from Mandakini River basin,Uttarakhand,India

The existing literature discussed only the aerial aspect and provided a brief description of tectonic-geomorphic correlation with field evidence.In present study we applied power law equations to estimate basin asymmetry factor(AF),Transverse topographic asymmetric factor(T),Hypsometric Integral(HI),longitudinal profile,stream length gradient index(SL),steepness index(Ksn),Chi(χ),and knick point(Kp)analysis to examine the response of tectono-climatic fluctuations in the Mandakini River basin,central Uttarakhand Himalaya.To decouple the causative tectono-climatic factors,we employed geospatial and Stream Power Incision Modeling(SPIM)techniques.SPIM is a globally accepted tool to predict an equilibrium state between fluvial erosion rates and the escalating function of stream power.It is actively applied in modeling the transformation of river systems especially in rugged topographic regions.The present study covers SPIM-based morphometric assessment of the tectonically sensitive Mandakini River basin between Ramgarh Thrust(RT)and Vaikrita Thrust(VT)in the central region of Uttarakhand Himalaya.In the upper reaches of the basin,U-shaped glaciated valleys dominate the landscape,while a rolling topography and deeply incised narrow valleys are depicted towards the downstream.Therefore,to understand the response of active tectonic over geomorphology,the drainage basin has been divided into two separate zones from the confluence point near the Rampur area.The modeling outcomes indicate that the Mandakini drainage basin is in a disequilibrium state where channels are actively incising to bedrock.Overall,AF of 32 and 70 indicate leftward tilting in the upper reaches and rightward tilting in the lower reaches of the basin,respectively.The HI value of 0.38 indicates a stage of maturity,characterized by a concave shape profile.Based on the analysis it may be concluded that the fragile lithology and tectono-climatic fluctuations are dominantly controlling the topography and valley floor morphology of the Mandakini River.

基于LCEM-GFEM方法爆炸载荷作用下含缺陷岩体损伤机理研究

在爆破作业过程中,岩体缺陷对裂纹扩展具有显著影响。本研究基于全局有限元方法的局部黏结单元(LCEM-GFEM)方法构建数值模拟模型,研究爆破作用下含缺陷岩体的损伤演化和裂纹扩展模式。通过引入能量传递系数,定量分析了缺陷形态对应力波传播和衰减的影响。结果表明,缺陷形态对岩体的损伤特性和裂纹扩展具有显著影响。随着平行缺陷夹角的增加,爆破诱发的裂缝与衍生裂缝的合并路径从缺陷末端转移到了缺陷中间,能量传递系数增加,分形维度减小。随着平行缺陷之间的水平距离增加,平行缺陷之间的裂缝数目和能量传递系数相应减少。随着垂直缺陷之间的垂直距离增加,穿过缺陷C的主水平裂缝长度增加,能量传递系数和分形维度也增加。研究结果可为受到爆破荷载作用下含缺陷岩体的损伤特征提供指导。

Evaluation of crustal deformation and associated strong motions induced by the 2022 Paktika earthquake,Afghanistan

The 2022 Paktika earthquake(moment magnitude:6.2) occurred on June 22,2022,near the border between the Khost and Paktika Provinces of Afghanistan,causing heavy damage and casualties in Paktika Province.This study evaluated the crustal deformation and associated strong motions induced by the Paktika earthquake.Crustal deformations were determined using the Differential Interferometric Synthetic Aperture Radar(DInSAR) technique and three-dimensional finite element method(3DFEM) and the results were compared.The permanent ground displacements obtained from the DInSAR and 3D-FEM analyses were similar in terms of amplitude and areal distribution.Strong motions were estimated using the 3D-FEM with and without considering regional topography.The estimations of maximum ground acceleration,velocity,and permanent ground deformations were compared among each other as well as with those inferred from failures of some simple structures in the Spera and Gayan districts.The inferred maximum ground acceleration and velocity from the failed adobe structures were more than 300 Gal and 50 cm/s,respectively,nearly consistent with the estimates obtained using empirical methods.The empirical method yielded a maximum ground acceleration of 347 Gal,whereas the maximum ground velocity was approximately50 cm/s.In light of these findings,some surface expressions of crustal deformations and strong ground motions,such as failures of soil and rock slopes and rockfalls,have been presented.The rock slope failures in the epicentral area were consistent with those observed during various earthquakes in Afghanistan and worldwide.

Presentation and management outcome of foot drop with tibialis posterior tendon transfer

BACKGROUND Foot drop causes considerable disability.The ankle-dorsiflexion is either weak or lost completely.Additionally,the ankle eversion and toe extensions are also impaired.This results in a high steppage gait while walking.Overall,the gait is awkward;there is greater energy consumption;increased proneness to sustain injury of the forefoot;and more frequent falling during walking.AIM To document the clinical and epidemiological profile of foot drop patients in our population and evaluate the outcome of tibialis posterior(TP)tendon transfer for restoring the lost dorsiflexion in foot drop.METHODS The study was carried out at the National Institute of Rehabilitation Medicine in Islamabad over a period of 7 years.It included patients of all sexes and ages who presented with foot drop and had no contraindications for the procedure of TP tendon transfer.Exclusion criteria were patients who had contraindications for the operation.For instance,paralyzed posterior leg compartment muscles,Achilles tendon contracture,stiff ankle or toes,unstable ankle joint,weak gastrocnemius and scarred skin spanning over the route of planned tendon transfer.Also,patients who had the foot drop as a result of disc prolapses or brain diseases were excluded.Convenience sampling technique was used.The circum-tibial route of TP tendon transfer was employed.RESULTS Out of 37 patients,26(70.27%)were males whereas 11(29.72%)were females.The mean age was 22.59±8.19 years.Among the underlying causes of foot drop,road traffic accidents constituted the most common cause,found among 20(54.05%)patients.The share of complications included wound infections in 3(8.10%)patients and hypertrophic scars in 2(5.40%)patients.At 1-year postoperative follow-up visits,the outcome was excellent in 8(21.62%),good in 20(54.05%)and moderate in 9(24.31%).CONCLUSION The majority of cases of foot drop resulted from road traffic accidents that directly involved the common peroneal nerve.TP tendon transfer through the circumtibial route was found to be an easily executed effective operation which restored good dorsiflexion of the ankle among the majority of patients.

Spatio-temporal evolution analysis of landscape pattern and habitat quality in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 based on InVEST model

Habitat quality is an important indicator for evaluating the quality of ecosystem.The Qinghai Province section of the Yellow River Basin plays an important role in the ecological protection of the upper reaches of the Yellow River Basin.To comprehensively analysis the alterations of habitat quality in the Qinghai Province section of the Yellow River Basin,this study utilized the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model to calculate the habitat quality index and analyze the spatio-temporal variation characteristics of habitat quality in the study area from 2000 to 2022,and calculated seven landscape pattern indices(number of patches,patch density,largest patch index(LPI),landscape shape index(LSI),contagion index(CONTAG),Shannon diversity index,and Shannon evenness index)to research the variation of landscape pattern in the study area.The results showed that the number of patches,patch density,LPI,LSI,Shannon diversity index,and Shannon evenness index increased from 2000 to 2022,while the CONTAG decreased,indicating that the landscape pattern in the Qinghai Province section of the Yellow River Basin changed in the direction of distribution fragmentation,shape complexity,and heterogeneity.The average value of the habitat quality index in the Qinghai Province section of the Yellow River Basin from 2000 to 2022 was 0.90.Based on the value of habitat quality index,we divided the level of habitat quality into five categories:lower(0.00-0.20),low(0.20-0.40),moderate(0.40-0.60),high(0.60-0.80),and higher(0.80-1.00).Most areas were at the higher habitat quality level.The lower habitat quality patches were mainly distributed in Longyang Gorge and Yellow River-Huangshui River Valley.From 2000 to 2022,the habitat quality in most areas was stable;the increase areas were mainly distributed in Guinan County,while the decrease areas were mainly distributed in Xining City,Maqen County,Xinghai County,Qumarleb County,and Darlag County.To show the extent of habitat quality variation,we calculated Sen index.The results showed that the higher habitat quality area had a decrease trending,while other categories had an increasing tendency,and the decreasing was faster than increasing.The research results provide scientific guidance for promoting ecological protection and high-quality development in the Qinghai Province section of the Yellow River Basin.

Blast waveform tailoring using controlled venting in blast simulators and shock tubes

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive events.Shock tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance range.Some wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific configurations.This paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube facilities.The use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid Dynamics.Controlled venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast simulator.This control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast waves.This paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

Borderline lepromatous leprosy:A case report

Rationale:Lepromatous leprosy can have many atypical presentations,obscuring early diagnosis.We present a case of lepromatous leprosy,presenting with atypical features,which made a diagnostic dilemma.Patient concerns:A 48-year-old man presented with bilateral lower limb oedema and scaly“ichthyosis like”skin rash in both hands and feet,hepatosplenomegaly and pancytopenia,over a course of three months,without any classical features of leprosy.A skin biopsy revealed an unexpected diagnosis of borderline lepromatous leprosy.Diagnosis:Lepromatous leprosy.Interventions:Multi-drug regimen treatment with rifampicin,dapsone and clofazimine for lepromatous leprosy.Outcomes:The patient made a good clinical recovery.Lessons:In endemic settings,clinicians should be aware of similar atypical manifestations of leprosy to face the global challenge of eradicating this chronic deforming disease.

Fuzzy multi-criteria decision-making method-based operational assessment of Chinese electricity markets

The evaluation of the electricity market is crucial for fostering market construction and development.An accurate assessment of the electricity market reveals developmental trends,identifies operational issues,and contributes to stable and healthy market growth.This study investigated the characteristics of electricity markets in different provinces and synthesized a comprehensive set of evaluation indicators to assess market effectiveness.The evaluation framework,comprising nine indicators organized into two tiers,was constructed based on three aspects:market design,market efficiency,and developmental coordination.Furthermore,a novel fuzzy multi-criteria decision-making evaluation model for electricity market performance was developed based on the Fuzzy-BWM and fuzzy COPRAS methodologies.This model aimed to ensure both accuracy and comprehensiveness in market operation assessment.Subsequently,empirical analyses were conducted on four typical provincial-level electricity markets in China.The results indicate that Guangdong’s electricity market performed best because of its effective balance of stakeholder interests and adherence to contractual integrity principles.Zhejiang and Shandong ranked second and third,respectively,whereas Sichuan exhibited the poorest market performance.Sichuan’s electricity market must be improved in terms of market design,such that market players can obtain a fairly competitive environment.The sensitivity analysis of the constructed indicators verified the effectiveness of the evaluation model proposed in this study.Finally,policy recommendations were proposed to facilitate the sustainable development of China’s electricity markets with the objective of transforming them into efficient and secure markets adaptable to the evolution of novel power systems.

Vibration and noise mechanism of a 110 kV transformer under DC bias based on finite element method

Global energy and environmental issues are becoming increasingly problematic,and the vibration and noise problem of 110 kV transformers,which are the most widely distributed,have attracted widespread attention from both inside and outside the industry.DC bias is one of the main contributing factors to vibration noise during the normal operation of transformers.To clarify the vibration and noise mechanism of a 110 kV transformer under a DC bias,a multi-field coupling model of a 110 kV transformer was established using the finite element method.The electromagnetic,vibration,and noise characteristics during the DC bias process were compared and quantified through field circuit coupling in parallel with the power frequency of AC,harmonic,and DC power sources.It was found that a DC bias can cause significant distortions in the magnetic flux density,force,and displacement distributions of the core and winding.The contributions of the DC bias effect to the core and winding are different at Kdc=0.85.At this point,the core approached saturation,and the increase in the core force and displacement slowed.However,the saturation of the core increased the leakage flux,and the stress and displacement of the winding increased faster.The sound field distribution characteristics of the 110 kV transformer under a DC bias are related to the force characteristics.When the DC bias coefficient was 1.25,the noise sound pressure level reached 73.6 dB.

Design and Optimization of Solar Photovoltaic Brackets in Mountainous Areas Adapted to Complex Wind Environments

With the increasing global demand for renewable energy,the application of photovoltaic power generation in mountainous areas is gradually increasing.However,the complex wind environment in mountainous areas poses severe challenges to the design and optimization of solar photovoltaic brackets.Traditional design methods are difficult to cope with the changeable wind speed and direction in mountainous areas,resulting in structural instability or material waste.Researchers have identified the key factors affecting wind response through parametric research and dynamic wind response analysis,so as to optimize the brackets design and improve its adaptability and stability in complex wind environments.In this paper,the complexity of wind speed,wind direction and turbulence characteristics in mountainous areas and their influence on brackets design are explored.Through static and dynamic wind load analysis,the geometrical shape and material selection of the bracket are optimized to enhance its wind resistance.The application of multi-objective optimization model and intelligent optimization algorithm provides an effective solution for the design of solar photovoltaic brackets,ensuring their safety and reliability in complex wind environments.

Discussion on the Soil and Water Conservation Model in Mountain Photovoltaic Power Generation Project

In the context of rising global energy demand and increasing awareness of environmental protection,photovoltaic power generation,as a clean and renewable form of energy,has become increasingly important and has received widespread attention and application worldwide.However,during the construction and operation of mountain photovoltaic power generation projects,water and soil erosion has become a major challenge,which not only restricts the sustainable development process of the project,but also has a significant negative impact on the local ecological environment.This article deeply analyzes the multiple causes,extensive impacts and effective prevention and control strategies of water and soil erosion in mountain photovoltaic power generation projects.The results show that rainfall intensity,terrain slope,soil type and vegetation coverage are the four key factors leading to soil erosion.Soil erosion not only causes a sharp decline in soil fertility,but also aggravates the problem of sediment deposition in rivers and reservoirs,and poses a direct threat to the stability and operating efficiency of photovoltaic equipment.In order to deal with the above problems,this paper innovatively puts forward a series of soil and water conservation technologies,covering multiple dimensions such as engineering measures,plant measures,farming measures and temporary measures,and deeply discusses the application models and management strategies of these measures in key stages such as planning and design,construction,operation and maintenance.Through specific case analysis,the successful practical experience of soil and water conservation is refined and summarized,and the key role of community cooperation,technical support and modern monitoring technology in preventing and controlling soil and water erosion is further emphasized.This article aims to achieve a win-win situation of ecological environment protection and energy development and utilization through scientific planning and effective governance,and contribute to the construction of a green,low-carbon,and sustainable energy system.

Colorectal resections for malignancy: A pilot study comparing conventional vs freehand robot-assisted laparoscopic colectomy

BACKGROUND Laparoscopic colectomy is widely accepted as a safe operation for colorectal cancer,but we have experienced resistance to the introduction of the FreeHandffrobotic camera holder to augment laparoscopic colorectal surgery.AIM To compare the initial results between conventional and FreeHandffrobot-assisted laparoscopic colectomy in Trinidad and Tobago.METHODS This was a prospective study of outcomes from all laparoscopic colectomies per-formed for colorectal carcinoma from November 29,2021 to May 30,2022.The following data were recorded:Operating time,conversions,estimated blood loss,hospitalization,morbidity,surgical resection margins and number of nodes har-vested.All data were entered into an excel database and the data were analyzed using SPSS ver 20.0.RESULTS There were 23 patients undergoing colectomies for malignant disease:8(35%)FreeHandff-assisted and 15(65%)conventional laparoscopic colectomies.There were no conversions.Operating time was significantly lower in patients under-going robot-assisted laparoscopic colectomy(95.13±9.22 vs 105.67±11.48 min;P=0.045).Otherwise,there was no difference in estimated blood loss,nodal harvest,hospitalization,morbidity or mortality.CONCLUSION The FreeHandffrobot for colectomies is safe,provides some advantages over conventional laparoscopy and does not compromise oncologic standards in the resource-poor Caribbean setting.

An overview of grid-forming technology and its application in new-type power system

To address the global climate crisis,achieving energy transitions is imperative.Establishing a new-type power system is a key measure to achieve CO_(2) emissions peaking and carbon neutrality.The core goal is to transform renewable energy resources into primary power sources.The large-scale integration of high proportions of renewable energy sources and power electronic devices will dramatically change the operational mechanisms and control strategies of power systems.Existing wind and solar converters mostly adopt the grid-following control mode,which leads to significant challenges in system security and stability as it is insufficient to support the frequency and voltage of the grid.On the other hand,grid-forming control technology(GFM)can provide voltage and frequency support for the system,and thus becomes an effective measure to improve the inertia and damping characteristics of power systems.This paper illustrates the principles,control strategies,equipment types,application scenarios,and project implementation of grid-forming technology.The simulation and analysis based on a renewable-dominated real new-type power system show that GFM can significantly enhance the frequency and voltage support capacity of the power system,improve renewable energy accommodation capacity and grid transmission capacity under weak grid conditions,and play an important role in enhancing the stability and power supply reliability of renewable-dominated new-type power systems.