响水化工厂爆炸TNT当量估算

为了使人们更清楚地了解爆炸的危险性,需要对爆炸事件的TNT当量进行计算,以2019·响水化工厂爆炸事件为例,对该爆炸事件的TNT当量进行了估算。在分析此次爆炸原因的同时,对比分析了多种TNT当量的计算方法,确定此次爆炸事故以建筑物的破坏程度计算TNT当量。根据爆炸事故现场建筑物的破坏情况,先确定出在爆炸周边不同距离处空气冲击波的超压范围,再运用萨道夫斯基公式计算出不同距离处不同TNT当量炸药爆炸产生的空气冲击波超压,将计算值与确定出的空气冲击波超压范围值进行对比,最终确定出爆炸事故的TNT当量。估算此次爆炸事故的TNT当量在400～500 t。     

双金属爆炸焊接下限

在爆炸焊接中,爆炸焊接参数的确定是非常重要的。文章总结了已有的爆炸焊接参数窗口理论,根据爆炸力学与爆炸焊接基本原理,发展出双金属爆炸焊接参数窗口的下限理论。     

响水化工厂爆炸TNT当量估算

为了使人们更清楚地了解爆炸的危险性,需要对爆炸事件的TNT当量进行计算,以2019·响水化工厂爆炸事件为例,对该爆炸事件的TNT当量进行了估算。在分析此次爆炸原因的同时,对比分析了多种TNT当量的计算方法,确定此次爆炸事故以建筑物的破坏程度计算TNT当量。根据爆炸事故现场建筑物的破坏情况,先确定出在爆炸周边不同距离处空气冲击波的超压范围,再运用萨道夫斯基公式计算出不同距离处不同TNT当量炸药爆炸产生的空气冲击波超压,将计算值与确定出的空气冲击波超压范围值进行对比,最终确定出爆炸事故的TNT当量。估算此次爆炸事故的TNT当量在400～500 t。     

双金属爆焊接下限

在爆炸焊接中,爆炸焊接参数的确定是非常重要的。文章总结了已有的爆炸焊接参数窗口理论,根据爆炸力学与爆炸焊接基本原理,发展出双金属爆炸焊接参数窗口的下限理论。     

一起配制特种混合气时发生的气瓶爆炸

介绍一起在配制混合气时的气瓶爆炸事故 ,造成 1个死亡 ,3人受伤 ,对爆炸事故进行了全面分析 ,确定为化学爆炸     

炸药水中爆炸能量定值装置不确定度的评定

炸药水中爆炸能量定值装置是用于对水中爆炸能量传递用标准物质进行定值,装置不确定度的准确性直接关系到标准物质的准确性,本文利用不确定度评定理论对影响炸药水中爆炸冲击波峰值压力、比冲击波能和比气泡能三项参数定值装置不确定度的因素进行了分析,并给出三项参数扩展不确定度的相对数值。     

一起氧气瓶爆炸事故分析

介绍氧气瓶爆炸事故概况和造成的伤亡,通过对事故现场以及气瓶碎片和其余气瓶内气体成分的分析,将此次爆炸确定为化学性爆炸。分析了爆炸事故的原因,并提出相应的预防措施。     

非理想炸药水下爆炸载荷传输特性对气背板结构响应的不确定度研究

为准确评估非理想炸药水下爆炸载荷传输过程中不确定度对舰船结构的毁伤效果的影响程度,该文采用误差分析理论推导出非理想炸药水下爆炸载荷中峰值压力和时间衰减常数的不确定度对气背板结构初期响应的影响规律。结合理想炸药与非理想炸药水下爆炸试验数据,研究结果表明:非理想炸药水下爆炸冲击波峰值压力和时间衰减常数的不确定度明显高于理想炸药的载荷不确定度,并且能够对0.01 m厚度的气背钢板结构初期响应产生7%~9%的相对不确定度,在评估非理想炸药水下爆炸对舰船结构毁伤效果时值得注意。     

石化企业火灾爆炸事故统计分析

统计分析石化企业火灾爆炸事故,找出火灾爆炸事故发生的规律性,确定石化企业生产过程的安全管理重点。     

建筑结构抗爆设防性能目标研究

近年来建筑结构的爆炸事件频繁发生,而我国目前还没有统一的建筑结构抗爆设防目标。基于安全性风险评估理论,利用爆炸风险平均发生概率和爆炸风险破坏程度的等级划分,确定爆炸风险的平均影响程度。结合我国《建筑结构可靠度设计统一标准》和实际爆炸事件的特点,提出基于建筑结构重要性的抗爆设防等级分类方法,从而确定抗爆安全等级。根据我国国情综合考虑建筑结构抗爆安全等级和爆炸超压强度等级,确定不同类型建筑结构的抗爆设防指标。建立了以建筑结构设防目标作为工程抗爆设计的基础原则,通过对以往爆炸事件的统计分析,确定不同爆炸超压荷载对人员伤亡和建筑结构损伤程度的设防目标,为建筑结构抗爆设防指标提供一种新的方法。     

The transverse elastic impact response of thick hollow cylinders

The two objectives of the studies in this paper were to determine the transient elastic impact response of thick-walled hollow cylindrical structures and to determine how this response was affected by the presence of flaws in the cylinder. These studies were aimed at determining the feasibility of using the impact-echo method for detecting flaws in the cylindrical concrete structures, such as pipes. Three-dimensional finite element models and laboratory specimens containing various types of flaws at known locations were used in the studies. It is shown that, for a hollow cylinder having a length greater than about eight times its outer diameter, the impact response as measured at points close to the impact point is composed of a number of resonant frequencies caused by cross-sectional (flexural) modes and a thickness frequency caused by dilatational waves reflected between the inner and outer wall surfaces. Equations are presented which relate the response of a hollow cylinder to the frequency of the fundamental cross-sectional (flexural) mode of a solid circular bar. It is shown that the location of cracks, areas of reduced wall thickness, and honeycombing as well as the depth of surface-opening cracks can be determined.     

The shape of a liquid surface in a uniformly rotating cylinder in the presence of surface tension

The free-surface shape of a liquid in a uniformly rotating cylinder in the presence of surface tension is determined before and after the onset of dewetting at the bottom of the cylinder. Two scenarios of liquid withdrawal from the bottom are considered, with and without deposition of thin film behind the liquid. The governing non-linear differential equations for the axisymmetric liquid shapes are solved numerically by an iterative procedure similar to that used to determine the equilibrium shape of a liquid drop deposited on a solid substrate. The numerical results presented are for cylinders with comparable radii to the capillary length of liquid in the gravitational or reduced gravitational fields. The capillary effects are particularly pronounced for hydrophobic surfaces, which oppose the rotation-induced lifting of the liquid and intensify dewetting at the bottom surface of the cylinder. The free-surface shape is then analyzed under zero gravity conditions. A closed-form solution is obtained in the rotation range before the onset of dewetting, while an iterative scheme is applied to determine the liquid shape after the onset of dewetting. A variety of shapes, corresponding to different contact angles and speeds of rotation, are calculated and discussed.     

Cylinder gauge measurement using a position sensitive detector

A position sensitive detector (PSD) has been used to determine the diameter of cylindrical pins based on the shift in a laser beam's centroid. The centroid of the light beam is defined here as the weighted average of position by the local intensity. A shift can be observed in the centroid of an otherwise axially symmetric light beam, which is partially obstructed. Additionally, the maximum shift in the centroid is a unique function of the obstructing cylinder diameter. Thus to determine the cylinder diameter, one only needs to detect this maximum shift as the cylinder is swept across the beam.     

Fracture resistant properties of AerMet steels

The purpose of this study is to report well-controlled experiments conducted to determine the fracture resistant properties of AerMet® 100 steels. One of the objectives of this study is to determine the influence of fracture toughness properties on the fracture and fragmentation process. Both sphere impact tests and cylinder expansion test geometry were used to determine the dynamic fracture resistant coefficients. These experiments were conducted at strain rates of 14 × 10³ /s for the cylinder expansion tests; the strain rates for the sphere impact tests varied over 50 to 100 × 10³/s. Fracture resistant coefficients of 60 MPa √m and 20 MPa √m are obtained from the cylinder test and the sphere impact test, respectively. These measurements do not agree with the static fracture toughness values reported in the literature.     

Profiles of interval bounds around the coordinates of antistigmatic powers

A cylinder that supplements the best vision sphere power appropriately, may improve visual acuity, but this cylinder power can displace the circle of least confusion. A sphere of opposite sign and half the power of the cylinder lens moves the circle back. This added sphere combined with the cylinder is the power of a cross-cylinder lens which, when resolved into independent components called the orthogonal and the oblique antistigmatic components, contains unique, meaningful, calculation-friendly dioptric powers. We calibrate bounds around the antistigmatic coordinates with regular bounds estimated around pure cylinder refractions. The bounds that are then plotted are called profiles of power ranges. The purpose of this article is to determine whether profiles of bounds of the components of antistigmatic lenses, are well-behaved with good foundation with respect to all cylinder axes. Profiles convey the degree of confidence and are key indicators of the quality of the reported powers or calculation.     

Numerical and experimental investigation on the breast cancer tumour parameters by inverse heat transfer method using genetic algorithm and image processing

This study presents numerical and experimental investigation on breast cancer tumour parameters by inverse heat transfer method using genetic algorithm (GA) and image processing (IP) to determine the depth and rate of heat generation of a breast cancer tumour. To simulate the problem, using the energy equation in a cylinder including a heater, the surface temperature distribution was obtained. Then, the temperature surface of the cylinder was analysed by the GA in MATLAB software to determine the depth and rate of heat generation of heater. The validity of the numerical method was evaluated using the IP from a laboratory sample. A thermal heater was placed inside a cylinder and was covered by a tissue similar to the human body tissue. According to the obtained results, it was determined that the results of the laboratory sample and the numerical method were in agreement with each other. Finally, these steps were applied on the thermal image of a patient’s cancer breast to determine the depth and rate of heat generation of the breast tumour. It is shown that the average computational error between numerical and experimental results in this method to determine the depth of the tumour is about 8–10% and to determine the rate of tumour heat generation is about 0.01–1%.     

Diffraction of cylinders with longitudinal surface structures

We present a model to determine the light scattered by a metallic cylinder with longitudinal structures when the cylinder is illuminated by a Gaussian light beam in oblique incidence. The model is based on an approximate solution to the Helmholtz-Kirchhoff integral by means of the stationary-phase method. We have studied the variations of the diffraction pattern in terms of the size of the defect and other geometrical parameters. The width of the beam and the misalignment between the beam and the cylinder have also been considered, as well as the optical properties of the surface.     

Hydroelastic wave diffraction by a vertical cylinder

A linear three-dimensional problem of hydroelastic wave diffraction by a bottom-mounted circular cylinder is analysed. The fluid is of finite depth and is covered by an ice sheet, which is clamped to the cylinder surface. The ice stretches from the cylinder to infinity in all lateral directions. The hydroelastic behaviour of the ice sheet is described by linear elastic plate theory, and the fluid flow by a potential flow model. The two-dimensional incident wave is regular and has small amplitude. An analytical solution of the coupled problem of hydroelasticity is found by using a Weber transform. We determine the ice deflection and the vertical and horizontal forces acting on the cylinder and analyse the strain in the ice sheet caused by the incident wave.     

工业炸药裹包装置上翻包机构的图解法设计

使用图解法对工业炸药中包包装线上裹包装置中的翻包机构进行了设计。在介绍了问题的背景后,使用图解法首先确定气缸的行程及其规格,然后通过从一边试探的方式,三次试探就得到了问题的解答。研究表明,这种图解法对该类带气缸的连杆机构设计具有普遍的借鉴意义。     

Determination of the fracture cause in an aircraft motor cylinder

One of the six cylinders of an aircraft four-cycle motor was fractured in two pieces between the 13th–14th cooling fins. To determine the root cause of the fracture, it was necessary a preliminary observation of the whole motor to verify the state of valves, spark plugs, seats, and their disposition in order to determine a possible motor malfunction previous to the failure. Afterwards, a chemical and mechanical material characterization and a fracture surface fractographic study were carried out determining the heat treatment state using metallography and microscopy techniques. Observations of the external and inner cylinder surface were made to detect the possible presence of cracks or pitting. Some pitting were observed in the cylinder external wall. It was determined that material was a quenched and tempered steel, type AISI 4140, and the fracture was brittle presenting fractographic signs of a progressive fracture, concluding that the fracture was originated by a corrosion pit localized in the cylinder external wall that progressed by a fatigue mechanism.