Quantitative Analysis of Frosting Characteristics on the Drip Tray of A Cryogenic Valve for LNG Ships

Cryogenic valves play a crucial role in the production and transportation of liquefied natural gas(LNG),and are primarily responsible for efficiently controlling the inflow and outflow of LNG and regulating pressure.However,due to their operation in low-temperature and high-humidity environments,crucial components such as drip trays are susceptible to frosting,which may lead to LNG leakage,thereby causing severe safety incidents.In this study,the user-defined function(UDF)is employed to redevelop Fluent,which integrates the frost growth model with the Eulerian multiphase flow model,to conduct a quantitative analysis of frosting on drip trays of cryogenic valves.The effects of environmental parameters,such as wind speed,ambient temperature,air humidity,and cold surface temperature on the growth of the frost layer were analyzed.This study reveals a limiting wind speed between 1 m/s and 2 m/s.Upon reaching this limit speed,the growth of the frost layer reaches its maximum,and further increases in the wind speed have no significant effect on the growth of the frost layer.Furthermore,the influence of the change in the flow field on droplet impingement and freezing during the growth of the frost layer is considered through the coupling method of the kinematic characteristics of water droplets and the collection coefficient of water droplets.This study identifies the influence of different parameters on the droplet impact efficiency,leading to the modification of the frost layer on the drip tray.

Frost deformation and microstructure evolution of porous rock under uniform and unidirectional freeze-thaw conditions

The frost deterioration and deformation of porous rock are commonly investigated under uniform freeze-thaw(FT)conditions.However,the unidirectional FT condition,which is also prevalent in engineering practice,has received limited attention.Therefore,a comparative study on frost deformation and microstructure evolution of porous rock under both uniform and unidirectional FT conditions was performed.Firstly,frost deformation experiments of rock were conducted under cyclic uniform and unidirectional FT action,respectively.Results illustrate that frost deformation of saturated rock exhibits isotropic characteristics under uniform FT cycles,while it shows anisotropic characteristics under unidirectional FT condition with both the frost heaving strain and residual strain along FT direction much higher than those perpendicular to FT direction.Moreover,the peak value and residual value of cumulative frost strain vary as logarithmic functions with cycle number under both uniform and unidirectional FT conditions.Subsequently,the microstructure evolution of rock suffered cyclic uniform and unidirectional FT action were measured.Under uniform FT cycles,newly generated pores uniformly distribute in rock and pore structure of rock remains isotropic in micro scale,and thus the frost deformation shows isotropic characteristics in macro scale.Under unidirectional FT cycles,micro-cracks or pore belts generate with their orientation nearly perpendicular to the FT direction,and rock structure gradually becomes anisotropic in micro scale,resulting in the anisotropic characteristics of frost deformation in macro scale.

Spatiotemporal dynamics of vegetation response to permafrost degradation in Northeast China

Permafrost in Northeast China is undergoing extensive and rapid degradation,and it is of great importance to understand the dynamics of vegetation response to permafrost degradation during different periods in this region.Based on the meteorological station data and MODIS land surface temperature data,we mapped the distribution of permafrost using the surface frost number(SFN)model to analyze the permafrost degradation processes in Northeast China from 1981 to 2020.We investigated the spatiotemporal variation characteristics of vegetation and its response to permafrost degradation during different periods from 1982 to 2020 using the normalized difference vegetation index(NDVI).We further discussed the dominant factors influencing the vegetation dynamics in the permafrost degradation processes.Results indicated that the permafrost area in Northeast China decreased significantly by 1.01×10^(5) km^(2) in the past 40 a.The permafrost stability continued to weaken,with large areas of stable permafrost(SP)converted to semi-stable permafrost(SSP)and unstable permafrost(UP)after 2000.From 1982 to 2020,NDVI exhibited a significant decreasing trend in the seasonal frost(SF)region,while it exhibited an increasing trend in the permafrost region.NDVI in the UP and SSP regions changed from a significant increasing trend before 2000 to a nonsignificant decreasing trend after 2000.In 78.63%of the permafrost region,there was a negative correlation between the SFN and NDVI from 1982 to 2020.In the SP and SSP regions,the correlation between the SFN and NDVI was predominantly negative,while in the UP region,it was predominantly positive.Temperature was the dominant factor influencing the NDVI variations in the permafrost region from 1982 to 2020,and the impact of precipitation on NDVI variations increased after 2000.The findings elucidate the complex dynamics of vegetation in the permafrost region of Northeast China and provide deeper insights into the response mechanisms of vegetation in cold regions to permafrost degradation induced by climate change.

Frost Resistance of Pervious Concrete Mixed with Waste Glass Powder

The contents of waste glass powder(WGP)(0%,10%,15%,20%,25%)and water-binder ratio(W/C)(0.24,0.26,0.28)were used as influencing factors,and the quality loss rate(Δm)and compressive strength loss rate(Δfc)were used as characterization parameters.The Ca/Si ratio and main element contents of C-S-H gels with different WGP content were investigated by energy dispersive spectrometry(EDS).The pore structure evolution characteristics of WGP composite cementing materials were investigated by low field nuclear magnetic resonance(NMR).UsingΔfc as the index of frost resistance degradation and Weibull function,the frost resistance degradation of glass doped pervious concrete(WGP-PC)was modeled.The results show that,with WGP,for the same number of cycles,Δm andΔfc decrease and increase with the increase of WGP.Under the same WGP content,Δm andΔfc decrease first and then increase with the increase of W/C.After 100 freeze-thaw cycles,the samples with WGP content of 20%and W/C of 0.26 have the best freeze-resistance.Microscopic tests show that with the increase of WGP content,the Ca/Si ratio of C-S-H gel decreases at first and then increases with the increase of WGP content.The extreme value of Ca/Si is 2.36 when WGP is added by 20%.The pore volume of hardened paste with 20%WGP content decreased by 18.6%compared with that of cement system without WGP.The overall compactness of the specimen was improved.On the basis of the test data,a life prediction model was established according to Weibull function.The experiment showed thatΔfc could be used as a durability degradation index,and the slope of the reliability curve became gentle after WGP was added,which reduced the damage degradation rate of PC.W/C was 0.26.It's about 5000 hours.

中文Frost多维度完美主义问卷的信效度检验

目的:检验中文Frost多维度完美主义问卷(FMPS)信效度。方法:共有1280名大学本科生作为被试填写了FMPS问卷,其1000名被试的数据用于探索性因素分析,另外280名被试的数据用于验证性因素分析。部分被试被要求填写测量焦虑、抑郁、强迫等心理困扰的问卷,作为效标效度检验。结果:中文版Frost多维度完美主义问卷由五个维度组成。各维度的项目载荷在0.45～0.78之间。五个因素(担心错误、条理性、父母期望、个人标准和行动的疑虑)可以解释总方差的53.7%。各维度的内部一致性系数为0.64～0.81,重测信度为0.63～0.82。中文FMPS与焦虑、抑郁、强迫等心理困扰也有显著的相关,其中“担心错误”和“行动的疑虑”与各种心理困扰的相关系数在0.30～0.70之间。结论:中文FMPS的维度结构与其英文原问卷相似,且具有令人满意的信效度,适合在中国文化环境下使用。

改进Frost算子在SAR图像斑点噪声抑制中的应用

针对合成孔径雷达(SAR)图像斑点噪声滤波的重要性以及存在的问题,对Frost滤波算法参数进行分析,指出了该算法等权滤波器在处理含有细节结构特征时存在盲目平滑的缺点,进而提出了改进方法。利用灰度差值计算权值,综合考虑滤波窗口内的强度信息,在一定程度上解决了盲目平滑的问题。实验验证了改进算法的有效性,并以斑点噪声指数和边缘保持指数为评价准则,通过与Frost算法比较,对改进算法在去除噪声和边缘保持方面的性能做了客观评价。

基于自适应微调因子的改进frost滤波

为避免frost滤波因使用同一微调因子带来边缘细节等结构信息的模糊,以及等距等权所带来的盲目平滑现象,对frost滤波算法提出了一种改进方案。该方案综合考虑滤波窗口本身的局域统计特性以及窗口内各像素本身的统计特性来自适应确定微调因子。通过对真实合成孔径雷达图像进行改进算法降噪实验,以等效视数和边缘保持指数两项指标为评价标准,并与不同微调因子的Frost滤波输出结果进行比较,结果表明改进算法比原算法有很大的改进,在边缘保持和去噪方面具有更好的滤波性能。

Evaluation of Cold Tolerance of Sugarcane under Drought Frost Condition

[Objective]The aim was to understand the change characteristics of sugarcane traits and evaluate the cold tolerance of sugarcane varieties under the drought and frost conditions.[Method] The experiment was carried out in Ziyuan County,Guangxi Province where the frost occurred often with 21 domestic and abroad sugarcane varieties（elites）.[Result] There were significant changes in the brix,green leaf number and photosynthetic rate of sugarcane before and after light frost and decreased more in cold-sensitive varieties.However,the correlation was only significant between the damage rate of stem length and internode,percentage of green leaves after heavy frost in relation to sugarcane brix and brix changes after light frost.Further analysis showed that the evaluation for cold tolerance of sugarcane would be more simple and reliable with traits of the damage rate of stem length and percentage of upper green leaves.The evaluation for varieties indicated that if it was not carried out for cold-tolerance identification in breeding program,the percentage of sugarcane varieties with good cold-tolerance will be lower than30%,and higher than 60% with poor cold-tolerance in subtropical and tropical regions.[Conclusion] This study had provided theoretical basis for the cold-resistant evaluation of sugar cane and the breeding of the varieties of cold-resistant.

一种基于修正Frost核的SAR图像斑点噪声抑制方法

针对合成孔径雷达(SAR)图像的斑点噪声抑制问题,给出了一种新的基于斑点噪声统计特性的滤波方法。该方法是对Frost滤波核的修正,综合考虑滤波窗口内的中心像元以及其他像元的局部统计信息,克服了传统Frost滤波器由于等权运算所带来的边缘等结构信息的模糊;同时也弥补了增强型Frost滤波器保留过多“假细节”的不足。实验结果表明,该方法在噪声抑制和细节保持方面取得了较好的折衷。

On Frightening Aspect of Robert Frost's Poems

Robert Frost is generally considered as a lyrical poet,whose poetry often gives the reader pleasant feeling.Yet,his poems have frightening quality,which can be perceived through the appaling world and seen in the great number of abnormal people described in his poems.This paper aims at offering a detailed analysis of 3 typical instances of such poems to illustrate that the frightening quality,in fact,reflects a kind of modern experience.

Audile Eyes and Imaginative Ears——Audio System in Robert Frost’s Poetry

Frost's poems enjoy great popularity among people worldwide. He has written a large number of poems with rich rhyme throughout his career. Frost uses metre and sound devices to reinforce the theme, giving a sense of beauty, and modifying the crude reality. People love his poems, and admire him for his clever using of audio system.

An Analysis of the Melancholy Colour in Robert Frost’s Poerty

Although a man stricken numerous times by pains and sufferings, Robert Frost had made the most excellent works in his lifetime. By carrying out a retrospection to Frost's rough life experiences and his times in light of their inseparable connection to and influence on his writing and analyzing the melancholy color presented in the main themes of "time"、"barrier"and "alienation and loneliness"which are concrete embodiments supporting the main element"melancholy", this thesis argues that Frost influenced his readers by inputting the element of melancholy into minds invisibly. With all the above efforts, the author of this thesis attempts to show a different side of Frost in a more specific and systematical way, and hopes it can help Frost readers understand him and read his poetry from a new angle.

基于改进后Sherwood-Frost本构模型对EPE冲击模拟

目的为了改进Sherwood-Frost本构模型,提升EPE高速、大变形冲击仿真精度。方法通过万能材料试验机对EPE进行静态压缩试验,获得不同压缩速率下的应力-应变曲线,结合热激活机制Seeger模型与反比例函数模型,对Sherwood-Frost本构模型应变率项进行改进,并用试验验证模型的可靠性;基于改进后的Sherwood-Frost本构模型,以ABAQUS软件为平台,对EPE材料进行冲击模拟仿真,并用试验数据验证仿真的准确性。结果模拟仿真结果与试验数据吻合良好;在冲击高度为1200,1300 mm的条件下,最大加速度误差分别为6%,2.03%。结论改进后的Sherwood-Frost本构模型具有良好的可靠性;基于该模型对EPE进行高速、大变形的冲击仿真,准确性较高。

Tree-Temperature Monitoring for Frost Protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation

Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran （a 0.17 ha peach orchard and a 0.24 ha orange orchard） to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 （control block -4.12℃, and sprinkled block ＋0.5℃） during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins （about 3.6% of the total area） were at the risk of low temperature due to the wind drift effects.

Frost-heaving pressure in geotechnical engineering materials during freezing process

Energy and resources including coal, oil, and gas are in demand all over the world. Because these resources near the earth's surface have been exploited for many years, the extraction depth has increased.As mining shafts in the coal extraction process become deeper, especially in western China, an artificial freezing method is used and is concentrated in the fractured rock mass. The frost-heaving pressure(FHP)is directly related to the degree of damage of the fractured rock mass. This paper is focused on FHP during the freezing process, with emphasis on the frost-heaving phenomenon in engineering materials. A review of the frost phenomenon in the geotechnical engineering literature indicates that:(1) During the soil freezing process, the ice content that is influenced by unfrozen water and the freezing rate are the determining factors of FHP;(2) During the freezing process of rock and other porous media, the resulting cracks should be considered because the FHP may damage the crack structure;(3) The FHP in a joint rock mass is analyzed by the joint deformation in field and experimental tests and can be simulated by the equivalent expansion method including water migration and joint deformation.

Frost heave control of fine round gravel fillings in deep seasonal frozen regions

Fine round gravel soil is widely employed in the subgrade of high and thawing. The lower the fines content in fine round gravel soil, but compaction difficulty increases. This study is to obtain the speed railways in cold regions to prevent frost heaving the smaller the quantities of frost heaving and thawing, optimum fines content and limited frost heaving and thawing. The fine round gravel soil filling （FRGSF） used in the Harbin-Qiqihaer Passenger Dedicated Line is taken as the study object. Influence of fines content on optimum water content, maximum dry density and frost heaving properties of FRGSF were studied by means of compaction and frost heaving tests. Results show that the maximum dry density of the FRGSF increases first and then decreases with an increase of fines content, namely there is an optimum fines content for easy compaction. The method of surface-vibratory instrument is fit for coarse-grained soils, and wet state of coarse-grained soil is in favor of compaction. Considering the relationship of fines content with maximum dry density and the frost heaving ratio of FRGSF, the fines content should be limited to within the range of 9%-10%, so that the frost heaving ratio is less than 1%, and the FRGSF is easily compacted. Water supply is proved to be an important factor influencing the amount of frost heaving of FRGSF. We also conclude that in the field, it is imperative to control waterproofing and drainage measures.

Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbeds in seasonally frozen ground regions

The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation （between October 2012 and January 2013）, and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements -- black pavement and insulation-black pavement -- to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field con- ditions of the Changchun section （D3K692＋840 to D3K692＋860）. The results show that： （1） Compared with cement pave- ment, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth; （2） the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3-1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7-0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7-8 ram, which would meet the deformation limit established by the Code for Design on Special Subgrade of Railway; （3） the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and （4） compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds.

Experiment on the frost resistance of Modified Phospho Gypsum: A case used to Improve Baozhong Railway Subgrade loess

It has been widely recognized that loess has a low stability and permeability,and it is susceptible to a sudden decrease in total volume or collapse upon wetting.When the railway subgrade was under the dynamic trainload,the loess subgrade was prone to instability and liquefaction.loess is higher than that of the cement modified loess,but lower than that of the MPG modified loess.However,the coefficient of permeability for the MPGcement modified loess has an opposite result,and the MPG-cement modified loess specimens have the best frost resistance.In addition,the mechanism of MPG-Bao Zhong railway is a key railway for Guyuan city,in Ningxia province of China,which is an important city of the Belt and Road.Due to the influence of largearea flood irrigation on the farmland,the subgrade had a degree of settlement.The settlement had not been alleviated after three treatments,which seriously affected the safety of the train.For this reason,cement,Modified Phospho Gypsum(MPG)and MPGcement were used to reinforce the subgrade loess,and the unconfined compressive strength test,permeability test and freeze-thaw cycle test were carried out.Then the compressive strength,impermeability and frost resistance of the three were analyzed and compared.The results indicate that the compressive strength of the MPG-cement modified cement modified loess is discussed.It is found that cement and MPG have two hydration reactions with water in loess.Ettringite,the hydration reaction product,which not only fills the pores,restricts the movement of the soil particles,but also acts as a connecting soil particle in the soil particles.Therefore,the strength of the modified loess continues to increase,and the physical properties of the modified loess are improved.

基于改进Frost滤波的SAR图像斑噪抑制算法

针对合成孔径雷达(SAR)图像斑点噪声严重影响目标检测、识别、变化检测等有用信息的提取这一问题,通过对Frost滤波算法进行深入分析,提出了改进的Frost滤波算法。该算法的改进主要对滤波器的权值作了两方面的调整:一是引入像元距离贡献度参数,将此参数的倒数与滤波窗口内对应的像元与中心像元之间的欧氏距离作积融入滤波器权值的计算;二是将滤波窗口内的像元灰度统计特性考虑入内,将像元与中心像元的灰度差融入滤波器权值的计算。改进后的滤波器权值可以自适应地调整,避免了原始Frost算法的滤波盲目性,在斑噪抑制能力提高的同时也改善了边缘保持的效果。仿真实验结果表明,所提改进Forst算法在斑噪抑制和边缘保持方面均优于原始Forst算法。

Highway Roadway Stability Influenced by Warm Permafrost and Seasonal Frost Action:A Case Study from Glennallen,Alaska,USA

Ground temperatures from four of the seven extensively studied highway cross-sections near Gulkana/Glennallen,Alaska during 1954;962,were chosen to better understand the impacts of highway construction on warm permafrost.Both the thawing of permafrost and seasonal frost action impacted on road surface stability for about 6 years until the maximum summer thaw reached about 3 m in depth.Seasonal frost action caused most of the ensuing stability problems.Unusually warm summers and the lengths of time required to re-freeze the active layer were far more important than the average annual air temperatures in determining the temperatures of the underlying shallow permafrost,or the development of taliks.The hypothesized climate warming would slightly and gradually deepen the active layer and the developed under-lying talik,but its effect would be obscured by unusually warm summers,by warmer than usual winters,and by the vari-able lengths of time of the zero curtains.At least one period of climate mini-cooling in the deeper permafrost during the early 20th century was noted.