Search results

This study presents a method for fabricating multi-material objects using a hybrid additive and subtractive approach. By hybridizing the material composition in addition to the fabrication process, functional requirements can be met more effectively than through homogenous material parts produced using a single manufacturing process. Development of multi-material objects consisting of dissimilar materials that have been hampered by a lack of a structural interface compatible with in-envelope hybrid additive and subtractive manufacturing.

This research presents a novel method for producing multi-material components through in-envelope hybrid additive and subtractive manufacturing. This study attempts to address the absence of a metal-polymer interface by integrating polymer additive manufacturing into a five-axis mill. The ability of the polymer additive system to reproduce overhang geometries is assessed with different levels of cooling. The relationship between structural performance, cooling and material flow rate is evaluated for the deposited carbon fiber reinforced acrylonitrile butadiene styrene.

A mechanically interlocking root structure is developed to form an interface between a machined aluminum region and a polymer region of an object. The tensile strength of the metal-polymer object is measured and found to be on the same order of magnitude as the bulk three-dimensional printed polymer.

By targeting the material properties to the local functional requirements within a part and taking advantage of both additive and subtractive manufacturing processes, this study will enable broader design options and optimization of performance metrics.

This paper aims to investigate the extent to which traditional manufacturers are equipped and interested in participating in a hybrid manufacturing system which integrates traditional processes such as machining and grinding with additive manufacturing (AM) processes.

A survey was conducted among traditional metal manufacturers to collect data and evaluate the ability of these manufacturers to provide hybrid – AM post-processing services in addition to their standard product offering (e.g. mass production).

The original equipment manufacturers (OEMs) surveyed have machine availability and an interest in adopting hybrid manufacturing to additionally offer post-processing services. Low volume parts which would be suitable for hybrid manufacturing are generally more profitable. Access to metal AM, process engineering time, tooling requirements and the need for quality control tools were equally identified as the major challenges for OEM participation in this evolving supply chain.

OEMs can use this research to determine if hybrid manufacturing is a possible fit for their industry using existing machine tools.

Survey data offer an unique insight into the readiness of metal manufacturers who play an integral role in the evolving hybrid supply chain ecosystem required for post-processing of AM metal parts. This study also suggests that establishing metal AM centers around OEMs as a shared resource to produce near-net AM parts would be beneficial.

This paper aims to discuss the development of a software tool UniverFilter™ which is capable of geometrical modelling of 3D woven fabrics, interfacing with computational fluid dynamics tools to numerically determine the fluid (and more specifically liquid) flow path and simulating the filtration process by introducing particles of various shapes and sizes.

The method employed in creating the software tool is based on geometrical modelling of the single‐layer woven fabric with monofilament yarns, numerical analysis of the fluid‐flow problem, and mathematical modelling of the forces exerted on particles to accurately predict the settlement of such particles on the fabric. In the case of particle motion, a Lagrangian approach is used.

Creation of a software tool capable of simulation and modelling the filtration process through woven fabrics is the primary achievement. The effect of geometrical parameters of the woven fabric on fluid flow utilizing the results from fluid pressure and fluid velocity on the fabric show that the fluid flow is significantly influenced in the interstices and chamber downstream by the fabric. Fluid‐flow resistance and pressure loss are obtained from the results of fluid velocity and pressure. The results from the fluid pressure on the fabric could also be employed to more accurately predict how pore shapes and sizes are transformed.

Creation of a modelling tool for filtration through woven fabric media. This software is the foundation of establishing a standalone tool with the capability to design, test and improve fabric filter design for more efficient filtration properties.

Organizations are affected top-down by the overarching societies and bottom-up by foundational face-to-face encounters: societies provide norms, values, laws, institutions, beliefs, markets, political structures, and knowledge bases. What happens within organizations is done by people interacting with other people, arguing, discussing, convincing each other when preparing and making decisions. Organizations operate within social environments that leave their – however indirect – imprint on what is going on within organizations. This article argues that organizational sociology can benefit from an integrated theoretical framework that accounts for the embeddedness of organizations within the micro- and macro-levels of social order. The argument is developed in two main points: First, this article introduces the multilevel framework provided by Niklas Luhmann’s systems theory to demonstrate how organizations are shaped by the functionally differentiated macro-structure of society. Organizations follow and reproduce the operational logics of societal domains such as the political system, the economy, science, law, religion, etc. Second, this paper demonstrates how organizations are shaped by micro-level dynamics of face-to-face interactions. Face-to-face encounters form a social reality of its own kind that restricts and resists the formalization of organizational processes. Here, this article draws on Erving Goffman’s and Randall Collins’ work on interaction rituals, emotions, and solidarity, which is inspired by Durkheimian micro-sociology. At the end, this article brings together all the elements into one general account of organizations within the context of their macro- and micro-structural social environments. This account can yield a deeper and more sociological understanding of organizational behavior.

Complicated motion of vortex is frequently observed in the wake of islands. These kinds of swirling fluid cause the trap of sediments or pollutants, subsequently inducing the dead zone, odor or poor water quality. Therefore, the understanding of flow past a circular cylinder is significant in predicting water quality and positioning the immersed structures. This study aims to investigate the flow properties around a structure using Navier-slip boundary conditions.

Boundary conditions are a major factor affecting the flow pattern because the magnitude of flow detachment on a surface can redistribute the tangential stress on the wall. Therefore, the authors performed an analysis of laminar flow passing through a circular structure to investigate the effect of boundary conditions on the flow pattern.

The authors examined the relationship between the partial-slip boundary conditions and the flow behavior at low Reynolds number past a circular cylinder considering velocity and vorticity distributions behind the cylinder, lift coefficient and Strouhal number. The amplitude of lift coefficient by the partial slip condition had relatively small value compared with that of no-slip condition, as the wall shear stress acting on the cylinder became smaller by the velocity along the cylinder surface. The frequency of the asymmetrical vortex formation with partial slip velocity was increased compared with no-slip case due to the intrinsic inertial effect of Navier-slip condition.

The ability to engineer slip could have dramatic influences on flow, as the viscous dominated motion can lead to large pressure drops and large axial dispersion. By the slip length control, no-slip, partial-slip and free-slip boundary conditions are tunable, and the velocity distributions at the wall, vortex formation and wake pattern including the amplitude of lift coefficient and frequency were significantly affected by slip length parameter.

The following chapter analyses the ways in which unequal patterns of time develop effectiveness in childhood and adolescence. Central is the focus of the taken-for-granted experiences in the phase of growing up, the developing ways of life and value attitudes. In this context, questions arise about the extent to which children and adolescents help to shape the time patterns that are relevant to them and how an “equitable distribution” of “temporal resources” could be promoted.

Before starting research in the field of ethics, a few common assumptions need to be cleared up. The first is so common that it needs very little space at all: Ethics is a scientific discipline. This accurately describes its location and the problems it covers in a modern, functionally differentiated society. As a branch of philosophy and a normative science, its frame of reference is initially located in a world of possible competing reasons. The basic problem is that of trying to explain good reasons – and the horizon is the sayability of ethical sentences which, even when they reflect an ethical practice, open up a scientific horizon. Ethics is therefore a science – and like every science it can only solve scientific problems (see Luhmann, 2002, pp. 79–93). Practical problems are also the scientific problems of ethics – and that is not a deficiency, but rather a consequence of the basic structures of modern society. A modern society cut loose from political, economic, legal, scientific, artistic, educational and medical problems, on the one hand, allows these disconnected spheres to relate radically to each other, while on the other hand making them logically incompatible. A modern society could not exist any other way (see Luhmann, 1998, pp. 1–21; Nassehi, 2005a). This should first be understood before venturing into research on ethics.