Application to cleaning of waste plastic surfaces using atmospheric non-thermal plasma jets

The removal of paint on the surface of waste plastics is difficult by the conventional process; in this research, a new cleaning mechanism using atmospheric plasmas was examined through optical emission spectroscopy, electron spectroscopy for chemical analysis, and scanning electron microscopy. Results indicate that an increase of pulse frequency enables for a short processing time for the removal of the paint film, signifying that the production of radicals in plasma, especially oxygen radicals, can be controlled by pulse frequency.Plasma jets were generated under the experimental conditions of an input power of 250 W to 400 W, a pulse frequency of 2 kHz to 12 kHz, and a plasma gas flow rate of 30 L/min. Examination of the intensity ratio of the reactive species, as measured by emission spectroscopy, showed that the O/N value increased with an increase in pulse frequency. Results of analysis with electron spectroscopy for chemical analysis show that nitrogen atoms and molybdenum in only the paint film decreased through plasma processing.     

Limit loads and approximate J estimates for axial through-wall cracked pipe bends

This paper presents plastic limit loads and approximate J estimates for axial through-wall cracked pipe bends under internal pressure and in-plane bending. These loads and estimates are based on small strain finite element limit analyses using elastic-perfectly plastic materials. Geometric variables associated with the crack and pipe bend are systematically varied, and three possible crack locations (intrados, crown and extrados) are considered. Effects of the bend and crack geometries on plastic limit loads are quantified, and closed-form limit load solutions are given. Based on the proposed limit load solutions, a reference stress based the J estimation scheme for axial through-wall cracked pipe bends under internal pressure and in-plane bending is proposed.     

基于机器视觉的塑胶制品表面缺陷自动检测技术

详细阐述了机器视觉的照明系统、CCD摄像机、图像增强、图像分割、图像识别等关键技术的发展现状,并介绍了机器视觉技术在塑料电子元件、带材、PVC建材、薄膜、皮革、塑料瓶子等塑胶制品表面缺陷自动检测中的应用现状.     

高分子乳液型养护剂的研制及应用

通过优化养护剂组分,研制出有效保水率高、在新鲜混凝土面成膜快的高分子乳液型养护剂,室内对比研究了三种养护方式（标准养护、自然养护和养护剂养护）对混凝土强度、耐久性和塑性收缩、开裂的影响,并采用该养护剂在干旱风沙地区进行了工程应用。结果表明,与标准养护相比,养护剂养护下混凝土7d 前强度不降低,56d强度仅降低约5%,90d 自然碳化深度为0,氯离子渗透性略有增加;成膜养护剂能有效降低混凝土塑性收缩和开裂程度,用于干旱风沙地区混凝土养护具有明显的技术经济性能优势。     

变形镁合金的塑性加工技术研究及展望

介绍了变形镁合金材料的应用与开发、塑性变形特点及塑性变形工艺的最新发展,指出了变形镁合金研究开发的发展方向。     

A CONSTITUTIVE MODEL FOR ELASTIC-PLASTIC DEFORMATION UNDER CYCLIC MULTIAXIAL STRAINING

Abstract— The yield criterion is interpreted as defining the metric of the stress space. Hydrostatic stresses correspond to null geodesies. The plastic strain increment represents a normal projection of the increment undergone by a certain scalar function (hardening function) which depends only on the distance between stress points. This establishes a flow rule formally equivalent to the Prandtl-Reuss equations. Consideration of un-loading processes leads to the analysis of equivalent paths and to the definition of a generalized length or separation which provides a new representation of kinematic hardening.     

Fracture behavior of a corroded structural component under bending load

In order to clarify the significance of corrosion damage for risk assessment, bend tests were carried out on a roughened corroded annular plate prepared from an oil storage tank. It was found that a marked decrease of load carrying capacity occurred in the high deflection region depending upon the degree of corrosion damage. The reason for extensive loss of load carrying capacity was successfully explained from successive observation of crack growth behavior on the corroded surface of the annular plate. Photographic evidence showed that multiple cracks, initiated around individual pits, grew rapidly not only by crack growth, but also by coalescence with other neighboring cracks under the influence of plastic constraint derived from the welded joint. The linking up of multiple cracks leading to a catastrophic failure was considered to be a characteristic event of the roughened corroded component, and was expected to occur depending upon the degree of corrosion damage under a complex stress state.     

超深高温高压气井完井含伸缩管测试管柱的应力与变形特征

塔里木盆地MJ4井测试管柱长6 617 m,测试时井底压力为101.63 MPa,完井作业过程中管柱出现了塑性变形问题,迫切需要准确地确定管柱塑性变形究竟发生在完井作业的哪个阶段。为此,采用三维有限元分析方法,结合MJ4井坐封、压裂和试油3个典型的载荷工况,对管柱的变形和轴向应力分布进行了数值计算,总结了含伸缩管的完井测试管柱力学行为计算流程。研究内容主要包括:①提出了具有伸缩管的油管柱系统中伸缩管的伸长与闭合状态的判断依据,并给出了相应的计算原理和计算公式,计算了MJ4井油管柱伸缩管的伸长—闭合状态;②给出了水力锚咬合不良产生的封隔器环空附加压差载荷的分析计算方法,模拟了其对管柱系统变形行为的影响,指出了附加压差载荷对管柱的塑性屈曲变形有着重要的影响;③计算模型引入了侧向屈曲变形的限制,从而间接考虑了接箍刚度对屈曲变形的影响,计算分析了油管柱在各种载荷共同作用下的变形情况,得到的数值结果显示与观察到的变形现象相同。研究结果表明,MJ4井管柱的塑性变形发生在压裂改造施工阶段,各种形式的液体压力载荷及重力载荷是塑性变形的主要原因。结论认为,含伸缩管测试管柱的力学计算模型可作为优化施工和管柱系统结构设计的重要理论工具和分析手段。     

几种塑料的傅里叶变换拉曼光谱分析

采用傅里叶变换拉曼光谱(FTIR)技术对几种塑料样品进行了分析,并给出了几种塑料的傅里叶变换拉曼光谱图。该方法具有快速、准确、操作简便、重复性好、不需对样品进行分离,可直接分析等特点。