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控制裂缝曲生成的最佳汾酒大曲工艺筛选
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作者 张汝忠 王宝珠 李宇臣 《酿酒》 CAS 2021年第1期102-107,共6页
汾酒大曲是中温曲生产的典型代表,是传统工艺发酵的传承产物。为了有效提高汾酒大曲产品的内在质量,减少并控制裂缝曲的产生,以汾酒大曲操作方法为研究对象,根据制曲上道工序、生产过程进行对比、分析和研判,确定影响裂缝曲生成的主要... 汾酒大曲是中温曲生产的典型代表,是传统工艺发酵的传承产物。为了有效提高汾酒大曲产品的内在质量,减少并控制裂缝曲的产生,以汾酒大曲操作方法为研究对象,根据制曲上道工序、生产过程进行对比、分析和研判,确定影响裂缝曲生成的主要因素有5个,并进行生产的试验与验证,结果表明,湿曲坯入房水分控制在38%~41%之间正常运行;晾霉期的温度控制在32〜35℃;执行四层原倒的时间为24h左右;潮火延缓期温度控制在35-39℃;潮火延缓起火时间为1〜2d。在此条件下进行第2次验证性试验,最终测得糖化力为917.82mg/g·h,裂缝曲产生比例为6.6%,有效控制了裂缝曲的生成,符合汾酒大曲的成曲标准,验证筛选出来的最佳工艺确实可行。 展开更多
关键词 裂缝曲 粉碎度 温度 晾霉 四层原倒 潮火
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大体积腔体混凝土结构温度及裂缝分析与控制 被引量:8
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作者 于天佑 吴亚平 +3 位作者 杨青山 杨玫 金省华 蒋勇 《铁道科学与工程学报》 CAS CSCD 北大核心 2020年第3期690-698,共9页
大体积腔体结构混凝土温度裂缝多产生于内外温差较大处,为尽可能避免温度裂缝的发生,以宁波市下穿铁路框架桥涵大体积混凝土为依托,采用数值分析的方法,研究浇筑及养护过程中模板类型和环境温度对大体积混凝土腔体结构温度及裂缝的影响... 大体积腔体结构混凝土温度裂缝多产生于内外温差较大处,为尽可能避免温度裂缝的发生,以宁波市下穿铁路框架桥涵大体积混凝土为依托,采用数值分析的方法,研究浇筑及养护过程中模板类型和环境温度对大体积混凝土腔体结构温度及裂缝的影响,并结合现场试验数据,对其进行分析和论证。研究结果表明:对于大体积腔体现浇整体式箱涵结构,易出现由最高温度向侧板内侧偏移所导致的翘曲现象,容易在侧板内侧产生翘曲裂缝;钢模板浇筑比木模板浇筑的混凝土最高温度低10℃,侧板最大温差低16℃左右,最大应力低约0.9 MPa,最高温度出现时间比木模板推迟1 d左右,采用钢模及采用内外同条件养护可以有效减少翘曲裂缝的产生;对于大体积腔2次浇筑框架桥结构,养护过程中在侧板长度方向易产生约0.2~0.4 mm竖向贯穿性裂缝。 展开更多
关键词 腔体混凝土结构 下穿铁路框架桥涵 模板类型 裂缝
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A study of wavelet transforms applied for fracture identification and fracture density evaluation 被引量:3
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作者 张晓峰 潘保芝 +1 位作者 王飞 韩雪 《Applied Geophysics》 SCIE CSCD 2011年第2期164-169,178,179,共8页
Combining wavelet transforms with conventional log differential curves is used to identify fractured sections is a new idea.In this paper,we first compute the mother wavelet transform of conventional logs and the wave... Combining wavelet transforms with conventional log differential curves is used to identify fractured sections is a new idea.In this paper,we first compute the mother wavelet transform of conventional logs and the wavelet decomposed signals are compared with fractures identified from image logs to determine the fracture-matched mother wavelet.Then the mother wavelet-based decomposed signal combined with the differential curves of conventional well logs create a fracture indicator curve,identifying the fractured zone.Finally the fracture density can be precisely evaluated by the linear relationship of the indicator curve and image log fracture density.This method has been successfully used to evaluate igneous reservoir fractures in the southern Songnan basin and the calculated density from the indicator curve and density from image logs are both basically consistent. 展开更多
关键词 Wavelet transform fracture identification differential curves fracture density
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与挠曲作用相关的一种特殊裂缝形成机制 被引量:1
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作者 董有浦 肖安成 +2 位作者 吴磊 毛黎光 徐波 《地球科学(中国地质大学学报)》 EI CAS CSCD 北大核心 2013年第4期755-762,共8页
浙江省临安市上侏罗统劳村组火山凝灰岩露头中发育了很多与挠曲相关的裂缝,地层构造简单、露头良好,为研究与挠曲相关裂缝提供了良好的条件.通过对两处野外露头的精细测量,发现裂缝面平直、且未被充填,均为构造裂缝,在剖面上裂缝的组合... 浙江省临安市上侏罗统劳村组火山凝灰岩露头中发育了很多与挠曲相关的裂缝,地层构造简单、露头良好,为研究与挠曲相关裂缝提供了良好的条件.通过对两处野外露头的精细测量,发现裂缝面平直、且未被充填,均为构造裂缝,在剖面上裂缝的组合呈扇形.裂缝面与岩层层面夹角为44°~80°,裂缝密度随着地层厚度的增加而增加.根据裂缝面与层面的交切关系,将两组裂缝分别命名为:锐夹角指示邻层相对运动方向的D裂缝和锐夹角指示本层相对运动方向的D裂缝.通过对地层挠曲变形的几何分析,发现两组裂缝的形成是为了调节核部地层在变形过程中产生缩短量和剩余剪切,地层厚度与地层中产生剩余剪切成正比.结果表明,地层厚度越大,形成的裂缝也越多. 展开更多
关键词 相关裂缝 露头 几何分析 形成机制 构造地质学
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Seismic wavefield modeling in media with fluid-filled fractures and surface topography 被引量:2
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作者 兰海强 张中杰 《Applied Geophysics》 SCIE CSCD 2012年第3期301-312,361,共13页
We present a finite difference (FD) method for the simulation of seismic wave fields in fractured medium with an irregular (non-fiat) free surface which is beneficial for interpreting exploration data acquired in ... We present a finite difference (FD) method for the simulation of seismic wave fields in fractured medium with an irregular (non-fiat) free surface which is beneficial for interpreting exploration data acquired in mountainous regions. Fractures are introduced through the Coates-Schoenberg approach into the FD scheme which leads to local anisotropic properties of the media where fractures are embedded. To implement surface topography, we take advantage of the boundary-conforming grid and map a rectangular grid onto a curved one. We use a stable and explicit second-order accurate finite difference scheme to discretize the elastic wave equations (in a curvilinear coordinate system) in a 2D heterogeneous transversely isotropic medium with a horizontal axis of symmetry (HTI). Efficiency tests performed by different numerical experiments clearly illustrate the influence of an irregular free surface on seismic wave propagation in fractured media which may be significant to mountain seismic exploration. The tests also illustrate that the scattered waves induced by the tips of the fracture are re-scattered by the features of the free surface topography. The scattered waves provoked by the topography are re-scattered by the fractures, especially Rayleigh wave scattering whose amplitudes are much larger than others and making it very difficult to identify effective information from the fractures. 展开更多
关键词 finite difference MODELING FRACTURE irregular free surface curvilinear coordinate
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A New Fracture Criterion for a Crack under Combined Mode Loading
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作者 周小平 王建华 《Journal of Shanghai Jiaotong university(Science)》 EI 2003年第1期89-91,共3页
A new fracture criterion was proposed. The physical explanation of the criterion is that crack will propagate when the minimum strain energy density in iso hoop stress curve reach a critical strength of the material c... A new fracture criterion was proposed. The physical explanation of the criterion is that crack will propagate when the minimum strain energy density in iso hoop stress curve reach a critical strength of the material considered. The resulting curve of critical fracture of mixed mode cracks shows that the present fracture is efficient and more accurate than the previous criteria. 展开更多
关键词 fracture criterion combined mode loading minimum strain energy density in iso hoop stress curve
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A Comparative Study on the Flexural Behaviour of Waffle and Solid Slab Models When Subjected to Point Load
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作者 Akinyele J. Olawale Alade G. Ayodele 《Journal of Civil Engineering and Architecture》 2014年第5期588-594,共7页
The determinations of flexural behavior of some engineering structures are based on different theories and equations, but it has been observed that some of these equations may not give true representation. This work h... The determinations of flexural behavior of some engineering structures are based on different theories and equations, but it has been observed that some of these equations may not give true representation. This work has looked into the difference that may occur between theoretical and experimental results. An experimental test carried out on models of waffle and solid slabs structures were described and results from twenty test samples are presented. Each specimen was subjected to an incremental axial loading of 1 kN interval after 28 days of casting. The flexural moments, deflections and crack width at failure were obtained. The experimental flexural crack and theoretical flexural cracks for both types of slabs were compared. The result for flexural moments for waffle was 5.526 kNm, while solid slab was 3.684 kNm. The deflections showed that waffle slabs has 3.64 mm while solid has 9.28 mm, hence waffle has a higher structural stiffness than solid slabs, but the flexural cracks did not give the same results especially for the estimated crack width. It was concluded that estimated results based on developed equations may not be accurate because it is based on ideal situation. 展开更多
关键词 MODELS waffle slab solid slabs flexural moments flexural cracks deflections.
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Behavior and Flexural Prediction of Special Cementitious Bonding Material for Fiber Reinforced Strengthening Systems
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作者 Judy M. I. Soliman Tarek K. Hassan +2 位作者 Amr A. Abdelrahman Osama Hamdy Sami H. Rizkalla 《Journal of Civil Engineering and Architecture》 2017年第3期232-239,共8页
Strengthening of RC structures with externally bonded FRP (fiber reinforced polymers) has become an important challenge in civil engineering. Epoxy is the main bonding agent used so far, but in the case of a fire, i... Strengthening of RC structures with externally bonded FRP (fiber reinforced polymers) has become an important challenge in civil engineering. Epoxy is the main bonding agent used so far, but in the case of a fire, it is subjected to complete loss of his bonding capabilities. Mineral based composites strengthening systems consist of FRPs and a cementitious bonding agent which form a repair or strengthening system that is more compatible with the concrete substrata, and roved its efficiency. The current research introduces the use of a special cementitious material "Grancrete" as a bonding agent. Test results of 32 T-section RC beams strengthened with various FRG (fiber reinforced Grancrete) strengthening systems are presented. The results demonstrated that most of the specimens were likely to fail by debonding of the FRP from the concrete either at the ends or at intermediate flexural cracks. This paper presents an in-depth study aimed at the development of a better understanding of debonding failures in RC beams strengthened with externally bonded FRP systems. Different analytical models, published in the literature for plate end debonding, are reviewed and compared to test results. The results also demonstrated that when using U-wraps, the specimens were likely to fail by FRP sheet rupture. 展开更多
关键词 C Beam concrete DEBONDING intermediate crack debonding FRP Grancrete strengthening.
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An Improved Technique of Calculating Deflections of Flexural Reinforced Concrete Elements Made of Conventional and High-Strength Concrete
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作者 Gennadiy Murashkin Vasiliy Murashkin Denis Panfilov 《Journal of Civil Engineering and Architecture》 2013年第2期125-131,共7页
The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature ... The paper presents an improved technique of calculating total deflections of flexural reinforced concrete elements that takes discrete crack formation into account. The technique is based on determining the curvature of the cross section of reinforced concrete elements with cracks and fissures in the area between cracks. The curvature of the element is calculated using a non-linear function of the deformation of concrete under compression. Approximating dependency of concrete resistance on compression developed by one of the authors is presented. An algorithm of finding the curvature and formulas for calculating curvature and deflection are provided. The function of the curvature distribution along the length of a flexible element is proposed by the authors. The paper also presents the results of the author's experimental research. The characteristics of samples tested are described. The experimental research results of deflections of fiexural reinforced concrete elements made of conventional and high-strength concretes are presented. Comparison of the values calculated using the technique with those obtained from the experimental research as well as those calculated according to existing regulations in Russia, USA and Europe is drawn. 展开更多
关键词 DEFLECTION concrete tension diagram flexural elements.
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Hydraulic Properties Analysis of the Unsaturated Cracked Soil 被引量:1
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作者 曹玲 张华 陈勇 《Journal of Shanghai Jiaotong university(Science)》 EI 2017年第1期35-44,共10页
Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soi... Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soil during drying and wetting was measured in the test. Based on the test results, the relationships between the morphological parameters and the soil water content were quantified. According to the fractal model, the soil-water characteristic curve(SWCC) and permeability functions for the cracked soil were predicted based on the dynamical development process of the cracks. A crack-pore dual media model was established to simulate the ponding infiltration in the unsaturated cracked soil. The variations of the pore water pressure in different part of the fractal model are quite different due to the impact of the cracks. This result illustrates that the prediction of the hydraulic properties for the cracked soil is reasonable. 展开更多
关键词 expansive soil SEEPAGE fractal model soil-water characteristic curve (SWCC) crack-pore media TU 443 A
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