Salt Quench Hardening: An Overview

This presentation will provide the general audience with an overview of salt quench hardening, the pros and cons of working with salt, the benefits of salt quenching, and some of the various processes as well as types of equipment used when working with salt quench applications. We will answer the question “why salt?” by comparing it to traditional oil quench applications, by considering the characteristics of salt and how it promotes hardenability, ductility, tensile and yield strength, and by looking at the benefits of salt for distortion control, heat extraction, ease of washing, and the “green” side of recycling. We will address equipment layout configurations and the ancillary pieces of equipment required for an efficient operation, based on production requirements with a consideration of the specific part weight, geometry and annual volume. We will touch on NFPA guidelines and general safety practices. Finally, we will look at various processes associated with quenching in salt – austempering and marquenching, and as we conclude the presentation, we will discuss how material and process changes can lead to engineering optimization opportunities for “light-weighting”, mechanical feature enhancements, and process reduction.

Bend, Push, Stretch: Remarkable Structure and Mechanics of Single Intermediate Filaments and Meshworks

The cytoskeleton of the eukaryotic cell provides a structural and functional scaffold enabling biochemical and cellular functions. While actin and microtubules form the main framework of the cell, intermediate filament networks provide unique mechanical properties that increase the resilience of both the cytoplasm and the nucleus, thereby maintaining cellular function while under mechanical pressure. Intermediate filaments (IFs) are imperative to a plethora of regulatory and signaling functions in mechanotransduction. Mutations in all types of IF proteins are known to affect the architectural integrity and function of cellular processes, leading to debilitating diseases. The basic building block of all IFs are elongated α-helical coiled-coils that assemble hierarchically into complex meshworks. A remarkable mechanical feature of IFs is the capability of coiled-coils to metamorphize into β-sheets under stress, making them one of the strongest and most resilient mechanical entities in nature. Here, we discuss structural and mechanical aspects of IFs with a focus on nuclear lamins and vimentin.

High Temperature Aged Leakage Relaxation Screening Tests on Confined Flexible Graphite Gaskets

Flexible graphite-based gaskets are used extensively in high-temperature applications as a replacement of asbestos based gaskets. The effect of aging and temperature exposure of flexible graphite sheet gaskets was the subject of a previous work [1,2], however, the effect when flexible graphite is in a confined gasket configuration is not known. This study outlines the performance evaluation of the elevated temperature behavior of flexible graphite-based gaskets under a confined configuration and exposed over a long period employing HALR (High temperature Aged Leakage Relaxation) fixture. This ARLA-like fixture can retain the mechanical feature of the ATRS/HATR while allowing the cold leakage rate and weight loss measurement. Four different confined gasket configurations, namely corrugated metal, spiral wound, kammprofile and double jacketed, are evaluated within a temperature range of (427 to 649 °C) 800 to 1200 °F and exposure time of 2500 hours. Graphite weight loss, gasket thickness change, leakage and tightness parameter, creep and relaxation measurements were taken at regular intervals for each gasket style. To better understand the aging process, these critical mechanical and leakage properties are scrutinized; the degradation process related to mainly graphite oxidation is further discussed, and a conclusion is drawn.

Working Model of Rocker Bogie Mechanism (Earth Rover)

The Paper work "Rocker Bogie mechanism Geo-survey Rover" deals with attempt of improving the rover from its previous designs. The Geo-survey rover has got to operate rough and harsh environments that it had been designed but several factors restrict its operational capabilities, therefore the focus of our research is to overcome restrictions or to decrease it to within an acceptable range for its smooth performance.. The rover has been completely made from PVC to increase its capability to withstand shocks, vibrations and mechanical failures caused by the tough environment where it's operated on. NASA made and developed this mechanism to use it on Space missions. Whereas these bogies are also preferred by many earthly situations where human interference is needs to be neglected. Usual mobility designs are complicate, using many wheels or legs. It is a multi-wheeled rover capable of travel through rough terrain using an effective higher degree of mobility. Drive train simplicity is the effective mechanical feature of the rocker bogie design, which is accomplished by using only six motors for mobility. All motors are located inside the body where thermal variation is kept to a minimum which increases reliability and efficiency. Six wheels are used because there are few obstacles on natural terrain that need both front wheels of the rover to climb simultaneously. A series of mobility experiments within the agriculture land, rough roads, inclined, stairs and obstacles surfaces concluded that rocker bogie can achieve a long way traverses on field.

The Effect of Zirconia Material for Dental Implant To Osseointegrated Process

Objective: Tooth lost is the one of mostly case in dentistry. Dental implant are the proper and fast procedure to rehabilitated full or partial edentulous ridge. Many research and clinical study said that the successful of dental implant application are depend on osseointegration which considered by anatomical of the bone structure with implant or mechanical feature of implant. Dissucion : The composition of material and topographic surface are the important thing in osseointegration process . For many patient, Titanium give a good results, but some of patient worried because it can make a grey line in sub gingival or across the ridge which have a thin bone and soft gingival structure, So with zirconia implant hopefully that grey line doesn’t appear. Both of titanium and zirconia are very strong, Titanium have a high flexibility and fracture resistence but, zirconia have a low elasticity, which can cause a micro fracture. Conclusion : Zirconia implant have a good esthetics and looked naturally.

Mechanical properties of steel and polymer fiber reinforced concrete

The present study aimed to investigate the influence of a number of fiber parameters including fiber type, content and hybridization on strength and ductility of polymer fiber reinforced concrete (PFRC) and steel fiber reinforced concrete (SFRC) used mostly in tunneling practices as the primary shotcrete lining. Numerous cylindrical and prismatic beams were casted and undergone various tests in which main previously mentioned fiber traits varied. It was understood that SFRC excels at every mechanical feature in comparison to PFRC; however, such transcendence found predominant in compressive strength but marginal in flexural and tensile strength. Despite being classified under different compressive strength classes (SFRC in the upper and PFRC in the lower class) according to EFNARC, both FRC types fell under a similar flexural class (at 4% of fiber fraction); a result possibly in debt to excellent bonding properties and more slender polymer fibers. Tensile strength of PFRC was measured lower than SFRC. Augmentation of fiber content positively affected mechanical characteristics of FRC at most cases. Hybridization of different fibers at a specific range of fiber mixing proportions was observed to have advantageous impacts on ductility and strength of a more corrosive resistant and cost efficient hybrid fiber reinforced concrete (HFRC).

Frequency response analysis of heavy-load palletizing robot considering elastic deformation

For the palletizing robot’s operating characteristics of high speed, high acceleration, and heavy load, it is necessary to make a research on the structure optimization focusing on the vibration characteristics according to the mechanical and dynamic performance analysis. This article first introduces the mechanical feature and working principle of high-speed and heavy-load robot palletizer. Kinematics analysis is carried out by using D-H parameter method, which obtains positive kinematics solution and workspace. Jacobian matrix is deduced, and the relationship between joint space and Cartesian space is established. Second, for the reason that joint flexibility has a great influence on the vibration performance of the robot, a rigid–flexible coupling dynamic model is established based on the simplified model of the flexible reducer and Lagrange’s second equation to describe the joint flexibility of high-speed and heavy-load palletizing robot, and the vibration modes of the robot are analyzed. The influence of different joint stiffness on the frequency response of the system reveals the inherent properties of the heavy-load palletizing robot, which provides a theoretical basis for the optimal design and control of the heavy-load palletizing robot.

Long-term study on the effect of temperature on composite action and variation of neutral axis in slab on girder bridges

Composite action between steel girders and concrete slab is an important mechanical feature that needs to be maintained so that bridges can carry the applied load safely. This mechanical feature is maintained through the shear studs installed at the top flange of the steel girders. These shear studs keep the steel girders and the concrete slab working as one unit, resulting in a stronger section than if each element works separately. The composite action can be investigated using several methods of which one is the study of the position of the neutral axis (NA). The variation of the position of the NA over time gives an indication about the structural performance of the composite section. In this study, the variation of the position of the NA over time is investigated. Two bridges located in Manitoba were investigated in this study. The variation of the NA is observed as a result of variation of ambient temperature (temperature). Regression models are suggested to relate variation of the NA to the temperature that was measured beside the web of one of the bridge girders. Repeatability analysis over 4 years was conducted, confirming that the NA varies cyclically over years. It is suggested that this variation indicates that there is a change in the degree of composite action assuming that cold temperatures will induce more connection between the steel girders and the concrete slab as a result of thermal contraction of the shear studs. In addition, the stiffness of the material could be affected due to change of temperature. The other possibility is that an axial force develops in the beam as a result of the bearing restraint during the passing of vehicles on the bridge. The results found in this study will eventually lead to enhancements of the design procedures that currently assume a fixed position of the NA over time of composite sections of bridges, similar to the bridges presented in this study.