河南省雷电灾害风险评估进展及建议

河南省18个市均开展了雷电风险评估工作,但发展很不平衡,开展较好的已完成百余个项目,较差的刚起步。评估范围涉及有大型建设项目、爆炸火灾危险环境、普通住宅、重点工程、人员密集场所等。通过分析河南省部分雷击风险评估报告(以下简称《报告》),分别从技术和非技术方面分析了目前河南省雷电灾害风险评估工作的现状;针对存在问题提出了建议,并推荐雷击风险评估报告文本格式和雷击风险评估现场勘察原始记录项目内容。河南省目前雷击风险评估工作的重点、难点不在数据计算上,而是在雷电灾害分析、风险分量选取上,还应在《报告》编写上进一步改进,尤其是项目概述、结论、建议要规范、明确、具体,不能千篇一律。

易燃易爆场所雷电灾害风险评估的实践和探讨

根据山东省淄博市博山区雷暴日、闪电时空分布特征,参考IEC62305-2等标准规范,分析加油加气站建设项目所在地大气雷电环境状况和雷电灾害易损性,新增加了雷击火灾、爆炸影响范围评估内容,充分考虑毗邻区域的公共安全问题,最大限度减少雷击人身伤害和财产损失。为技术人员做好易燃易爆场所雷电灾害风险评估提供了可借鉴的技术方法和操作规程,简化风险评估模型,使雷电灾害风险评估分析、计算趋于科学和规范化。强调指出雷击风险评估是防御和减轻雷电灾害的关键环节。各类化工厂、易燃仓储、输送贮存油气、加油加气、烟花爆竹等易燃易爆场所应是雷电灾害风险评估的首要重点领域。

Technology Research on Lightning Strike Risk Evaluation of a Cable Car

According to structure function and lightning damage of a cable car, a feasible method of lightning strike risk evaluation for a cable car was put forward based on the evaluation model and evaluation method in the standard IEC62305-2. According to the difference between common buildings and cable cars, problems of height non-uniformity of equivalent section caused by inclination of the cable car and diversity of lightning activity regularity caused by the large area were resolved, and expected annual average frequency of lightning strike was calculated using three dimensional graphic approach and regional lightning characteristic analysis. Based on different types of damage process and loss consequences, according to interception effect against lightning invasion of the lightning protection measures and the method of probability selection proposed in the standard, the probability of casu- alty caused by direct lightning strike in a cable car and a waiting area as well as probabilities of casualty caused by failure of electronic information systems were cal- culated.

关于开展雷击风险评估工作的做法与思考

本文结合近几年青岛防雷工作,分析总结了青岛市气象防雷中心在强化防灾减灾、推进雷电灾害风险评估工作中取得的经验。

大型并网风力发电厂区域雷电灾害风险评估模型研究

本文根据大型并网风力发电机组雷电致灾特点以及所处环境的可能情况,设计包括闪电定位、区域雷电流幅值、海拔高程、区域风机(建筑物)高度、土壤电阻率、防雷分区LPZ以及控制系统指标等七个评价指标,通过对每个单独区域的各个指标进行计算,获得区域雷击灾害风险的相对程度与情况,并最终获得雷电灾害风险评估的数学模型。

Evaluating the Algorithm for Correction of the Bright Band Effects in QPEs with S-, C-and X-Band Dual-Polarized Radars

The bright band, a layer of enhanced radar reflectivity associated with melting ice particles, is a major source of signifi- cant overestimation in quantitative precipitation estimation （QPE） based on the Z-R （reflectivity factor-rain rate） relationship. The effects of the bright band on radar-based QPE can be eliminated by vertical profile of reflectivity （VPR） correction. In this study, we applied bright-band correction algorithms to evaluate three different bands （S-, C- and X-band） of dual-polarized radars and to reduce overestimation errors in Z-R relationship-based QPEs. After the reflectivity was corrected by the algo- rithms using average VPR （AVPR） alone and a combination of average VPR and the vertical profile of the copolar correlation coefficient （AVPR＋CC）, the QPEs were derived. The bright-band correction and resulting QPEs were evaluated in eight precipitation events by comparing to the uncorrected reflectivity and rain-gange observations, separately. The overestimation of Z-R relationship-based QPEs associated with the bright band was reduced after correction by the two schemes for which hourly rainfall was less than 5 mm. For the verification metrics of RMSE （root-mean-square error）, RMAE （relative mean absolute error） and RMB （relative mean bias） of QPEs, averaged over all eight cases, the AVPR method improved from 2.28, 0.94 and 0.78 to 1.55, 0.60 and 0.40, respectively, while the AVPR＋CC method improved to 1.44, 0.55 and 0.30, respectively. The QPEs after AVPR＋CC correction had less overestimation than those after AVPR correction, and similar conclusions were drawn for all three different bands of dual-polarized radars.

Accuracy assessment of mine walls＇ surface models derived from terrestrial laser scanning

The monitoring of highwall slopes at open-pit mines is an important task to ensure safe mining. For this reason, several techniques such as total station, radar, terrestrial Light Detection and Ranging （LIDAR） can be employed for surface measurement. The objective of this study is to investigate mesh algorithms, which can be used to interpolate 3D models of pit walls. Experiments were carried out at Coc Sau open-pit mine at Quang Ninh province of Vietnam, and at experimental mine of Akademia Gtrniczo-Hutnicza University of Science and Technology in Cracow, Poland. First, 3D point cloud data for the study area was acquired by using terrestrial LIDAR, then was used to generate mesh surfaces using three algorithms--Delaunay 2.5D XY Plane, Delaunay 2.5D Best Fitting Plane, and Mesh from Points. After that, the results were rectified and optimized. Subsequently, the optimized meshes were used for generation of non-uniform rational basis spline （NURBS） surfaces. Then, the NURBS surface accuracy was assessed. The results showed that the average distance between surface and point cloud was within range of 5.6-5.8 mm with deviation of 6.2-6.8 mm, depending on the used mesh. Additionally, the quality of surfaces depends on the quality of input data set and the algorithm used to generate mesh network, and the accuracy of computed NURBS surfaces fitting into pointset was 4-5 times lower than that of optimized mesh fitting. However, the accuracy of the final product allows determining displacements on the level of centimeters.

Assessing Post-Storm Forest Dynamics in the Pyrenees Using High-Resolution LIDAR Data and Aerial Photographs

We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial photographic comparisons to the current forest typology generated from airborne Li DAR data, and we examined the role of past natural disturbance on the current spatial distribution of forest structural types.We found six forest structural types in the landscape: early regeneration(T1 and T2), young even-aged stands(T3), uneven-aged stands(T4) and adult stands(T5and T6).All of the types were related to the timing and severity of past storms, with early-regeneration structures being found in areas markedly affected in recent times, and adult stands predominating in those areas that had suffered lowest damage levels within the study period.In general, landscapes where high or medium levels of damage were recurrent also presented higher levels of spatial heterogeneity,whereas the opposite pattern was found in the less markedly affected landscape, characterized by thepresence of large regular patches.Our results show the critical role that storm regimes in terms of timing and severity of past storms can play in shaping current forest structure and future dynamics in subalpine forests.The knowledge gained could be used to help define alternative forest management strategies oriented toward the enhancement of landscape heterogeneity as a measure to face future environmental uncertainty.

Debris flow hazard assessment by means of numerical simulations:implications for the Rotolon creek valley(Northern Italy)

On 4th November 2OLO, a debris flow detached from a large debris cover accumulated above the lowermost portion of the Rotolon landslide （Vicentine Pre-AIps, NE Italy） and channelized in the valley below within the Rotolon Creek riverbed. Such event evolved into a highly mobile and sudden debris flow, damaging some hydraulic works and putting at high risk four villages located along the creek banks. A monitoring campaign was carried out by means of a ground based radar interferometer （GB-InSAR） to evaluate any residual displacement risk in the affected area and in the undisturbed neighbouring materials. Moreover, starting from the current slope condition, a landslide runout numerical modelling was performed by means of DAN-3D code to assess the impacted areas, flow velocity, and deposit distribution of the simulated events. The rheological parameters necessary for an accurate modelling were obtained through the back analysis of the 2010 debris flow event. Back analysis was calibrated with all of the available terrain data coming from field surveys and ancillary documents, such as topographic, geomorphological and geological maps, with pre- and post-event LiDAR derived DTMs, and with orthophotos. Finally, to identify new possible future debris flow source areas as input data for the new modelling, all the obtained terrain data were reanalysed and integrated with the GB-InSAR displacement maps; consequently, new simulations were made to forecast future events. The results show that the integration of the selected modelling technique with ancillary data and radar displacement maps can be a very useful tool for managing problems related to debris flow events in the examined area.

Assessment Model of Atmosphere Transmitting Influence on High-resolution Airborne SAR Stereo Positioning

The influence derived from atmosphere transmitting of radar wave, in the application of high-resolution airborne Synthetic Aperture Radar (SAR) stereo positioning, may produce some phase errors, and eventually be introduced into positioning model. This paper described the principle of airborne SAR stereo positioning and the error sources of stereo positioning accuracy that arose from atmosphere transmitting, established a corresponding assess- ment model of atmosphere transmitting influence, and testified the model and the assessment principle taking the 1-m resolution airborne SAR images of Zigong City, Sichuan Province in China, as the test dataset. The test result has proved that the assessment model is reliable and reasonable. And, it has shown that the phase error arisen from time delay is the main error source during the atmosphere transmitting, which has much more influences on cross-track di- rection and introduces a stereo positioning error of about eight meters, but less on the along-track direction.

Preliminary Evaluation of Cloud Fraction Simulations by GAMIL2 Using COSP

The Cloud Feedback Model Intercomparisons Project (CFMIP) Observation Simulator Package (COSP) is adopted in the Grid-point Atmospheric Model of IAP LASG (GAMIL2) during CFMIP at Phase II to evaluate the model cloud fractions in a consistent way with satellite observations. The cloud simulation results embedded in the Atmospheric Model Intercomparison Project (AMIP) control experiment are presented using three satellite simulators: International Satellite Cloud Climatology Project (ISCCP), Moderate Resolution Imaging Spectroradiometer (MODIS), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) lidar onboard the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Overall, GAMIL2 can produce horizontal distributions of the low cloud fraction that are similar to the satellite observations, and its similarities to the observations on different levels are shown in Taylor diagrams. The discrepancies among satellite observations are also shown, which should be considered during evaluation.

Bootstrapping estimates of regression analysis for a non-random sample and its application in the research on anti-proliferation effects of triptolide

Objective: To solve the problem of parameter estimate in the regression analysis of non-random sample. Methods: Calculating residuals according to the regression function based on original data. Modifying residuals and correcting them with mean. Adding mean-corrected residuals on original response and bootstrapping them to get 1000 samples. Fitting regression functions of 1000 resampling samples and calculating the 2.5th percentile and 97.5th percentile of corresponding coefficient. Results: The interval estimates deriving from bootstrap method had more statistical significance than that from usual method. Conclusion: Bootstrapping a regression with residuals is a valid method for estimating parameter in regression analysis.

Evaluation of Rock Fall Hazards Using Lidar Technology

Lidar （light detection and ranging） is a relatively new technology that is being used in many aspects of geology and engineering, including researching the potential for rock falls on highway rock cuts. At Missouri University of Science and Technology, we are developing methods for measuring joint orientations remotely and quantifying the raveling process. Measuring joint orientations remotely along highways is safer, more accurate and can result in larger and more accurate data sets, including measurements from otherwise inaccessible areas. Measuring the nature of rock raveling will provide the data needed to begin the process of modeling the rock raveling process. In both cases, terrestrial lidar scanning is used to generate large point clouds of coordinate triplets representing the surface of the rock cut. Automated algorithms have been developed to organize the lidar data, register successive images without survey control, and removal of vegetation and non-rock artifacts. In the first case, we look for planar elements, identify the plane and calculate the orientations. In the second case, we take a series of scans over time and use sophisticated change detection algorithms to calculate the numbers and volumes of rock that has fallen off the rock face.

An Improved k-Equation Turbulence Model

LRN （low-Reynolds number） modifications to the NR （Norris-Reynolds） k-equation turbulence model are proposed and evaluated. The k and e that render the hybrid time scale are determined using the k-transport equation together with the Bradshaw and other algebraic relations. The eddy-viscosity coefficient Cμ and the empirical damping function are constructed such as to preserve the anisotropic characteristics of turbulence for application to non-equilibrium turbulent flows. The MNR （modified NR） model is applied to calculate two well-documented flows, yielding predictions in good agreement with the DNS （direct numerical simulation） and experimental data. Comparisons demonstrate that the MNR model offers a significant improvement over the original NR model and competitiveness with the Spalart-Allmaras one-equation turbulence model. The performance evaluation dictates that unlike the original NR model, the MNR model can be employed as a single-equation model instead of associating it with the two-layer model of turbulence.

Safety of ivabradine, a heart rate lowering drug: a systematic review and meta-analysis

As a novel heart rate lowing agent, ivabradine can reduce the heart rate by inhibiting the If （pacemaker） current in the sinoatrial node without affecting blood pressure or left ventricular systolic function. However, the safety of ivabradine remains controversial. In the present work, we aimed to assess any risk of cardiovascular mortality, bradycardia, phosphenes and atrial fibrillation associated with the ivabradine administration by recta-analysis. Studies were retrieved from PubMed, EMBASE, MEDLINE, Web of Science, Cochrane, www.clinicaltrials.gov web site and related conferences. Randomized controlled trials comparing ivabradine with comparators were identified and analyzed. Two reviewers independently extracted relevant information from the eligible trials and processed the data. This recta-analysis was performed by using Review Manager （5.3） and Stata （14.1） software. Moreover, sensitivity analysis and publication bias of the included studies were evaluated. A total of 12 randomized controlled trials meeting the inclusion criteria were included. Results of the meta-analysis revealed that there was no significant difference between ivabradine group and control groups in cardiovascular mortality （RR = 0.97, 95% CI： 0.89-1.06, P = 0.49）. While the administration of ivabradine was associated with a significant increase in the incidence of bradycardia （RR = 3.90, 95% CI： 2.47-6.17, P〈0.00001） and phosphenes （RR = 4.95, 95% CI： 3.24-7.55, P〈0.00001） as well as atrial fibrillation （RR = 1.24, 95% CI： 1.07-1.43, P = 0.003）. High quality of the included studies was confirmed by quality assessment. No publication bias was observed, and sensitivity analysis confirmed that the obtained results were stable. In conclusion, the meta-analysis proved that the use of ivabradine was associated with a significant increase in the risk of bradycardia, phosphenes and atrial fibrillation. Therefore, clinicians need to take these risks into account when using ivabradine in treatment.

Quantitative evaluation of NEXRAD data and its application to the distributed hydrologic model BPCC

The next-generation weather radar(NEXRAD) can generally capture the spatial variability of rainfall fields,but fails to provide accurate depth measurements.A systematic strategy to evaluate the accuracy of radar data in depth measurement and its performance in hydrologic model is outlined.Statistical evaluation coefficients are calculated by comparing NEXRAD data with individual raingauges as well as subbasin-averaged interpolations,and point-and surface-average factors are introduced to revise radar data successively.Hydrologic simulations are then performed with a distributed hydrologic model,called basin pollution calculation center(BPCC) with both raingauge observations and revised NEXRAD estimates inputs.The BPCC model is applied to Clear Creek Watershed,IA,USA,on an hourly scale,and the calibration and validation parameters are semi-automatically optimized to improve manual calibration shortcomings.Results show that hydrographs generated from both gauge and NEXRAD are in good agreement with observed flow hydrographs.Coefficient statistics reveal that NEXRAD contributes to model performance,indicating that NEXRAD data has the potential to be used as an alternative source of precipitation data and improve the accuracy of hydrologic simulations.

Performance of ground penetrating radar in root detection and its application in root diameter estimation under controlled conditions

A plant is stabilized by its root system. In congested urban cities such as Hong Kong, ground trenching is frequently seen due to the installation of utility lines along the roadside. Soil nailing, which involves soil coring in slopes, is a common solution to improve the slope stability. However, both activities inevitably pose a risk to the integrity of any root sys- tems present, and thus reduce the root anchorage. To prevent or minimize such damage, a careful design of the excava- tion/drilling location is of prime importance. Ground penetrating radar （GPR） provides a non-destructive method for locating roots by examining the contrast between the dielectric properties of the roots and the surrounding soil. To examine the perfor- mance of GPR and promote its use in Hong Kong, a test bed was prepared using local materials to create a controlled envi- ronment in which to conduct a series of systematic tests evaluating the performance of a 900 MHz GPR. The reflected radar- grams were subject to the influence of the following factors： size and depth of roots, horizontal distance between roots, and contrast between the root and soil water content. Correlations between root size and a number of waveform parameters were also explored. Limiting values for root size, root embedded depth, horizontal separation distance between roots, and water content contrast between root and soil were obtained. A significant correlation was found between the root diameter and time travel parameter T2 （p〈0.001, t=0.795）. Because GPR root detection is highly site-specific, this study provides a local refer- ence for GPR performance in the Hong Kong environment. The findings demonstrate that the 900 MHz GPR is applicable in Hong Kong for the detection of main roots.

Evaluation of convective heat transfer in a tube based on local exergy destruction rate

In this study, exergy efficiency is defined to evaluate convective heat transfer in a tube based on the local exergy destruction rate from the equilibrium equation of available potential. By calculating this destruction rate, the local irreversibility of convective heat transfer can be evaluated quantitatively. The exergy efficiency and distribution of local exergy destruction rate for a smooth tube, an enhanced tube into which short-width twisted tape has been inserted, and an optimized tube with exergy destruction minimization are analyzed by solving the governing equations through a finite volume method(FVM). For the smooth tube, the exergy efficiency increases with increasing Reynolds number(Re) and decreases as the heat flux increases, whereas the Nusselt number(Nu) remains constant. For the enhanced tube, the exergy efficiency increases with increasing Reynolds number and increases as the short-width rate(w) increases. An analysis of the distribution of the local exergy destruction rate for a smooth tube shows that exergy destruction in the annular region between the core flow and tube wall is the highest. Furthermore, the exergy destruction for the enhanced and optimized tubes is reduced compared with that of the smooth tube. When the Reynolds number varies from 500 to 1750, the exergy efficiencies for the smooth, enhanced, and optimized tubes are in the ranges 0.367–0.485, 0.705–0.857, and 0.885–0.906, respectively. The results show that exergy efficiency is an effective evaluation criterion for convective heat transfer and the distribution of the local exergy destruction rate reveals the distribution of local irreversible loss. Disturbance in the core flow can reduce exergy destruction, and improve the exergy efficiency as well as heat transfer rate. Besides, optimization with exergy destruction minimization can provide effective guidance to improve the technology of heat transfer enhancement.