967 resultados para Concept Design


Relevância:

30.00% 30.00%

Publicador:

Resumo:

The economic design of a distillation column or distillation sequences is a challenging problem that has been addressed by superstructure approaches. However, these methods have not been widely used because they lead to mixed-integer nonlinear programs that are hard to solve, and require complex initialization procedures. In this article, we propose to address this challenging problem by substituting the distillation columns by Kriging-based surrogate models generated via state of the art distillation models. We study different columns with increasing difficulty, and show that it is possible to get accurate Kriging-based surrogate models. The optimization strategy ensures that convergence to a local optimum is guaranteed for numerical noise-free models. For distillation columns (slightly noisy systems), Karush–Kuhn–Tucker optimality conditions cannot be tested directly on the actual model, but still we can guarantee a local minimum in a trust region of the surrogate model that contains the actual local minimum.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The general purpose of the EQUIFASE Conference is to promote the Scientific and Technologic exchange between people from both the academic and the industrial environment in the field of Phase Equilibria and Thermodynamic Properties for the Design of Chemical Processes. Topics: Measurement of Thermodynamic Properties. Phase Equilibria and Chemical Equilibria. Theory and Modelling. Alternative Solvents. Supercritical Fluids. Ionic Liquids. Energy. Gas and oil. Petrochemicals. Environment and sustainability. Biomolecules and Biotechnology. Product and Process Design. Databases and Software. Education.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A sequential design method is presented for the design of thermally coupled distillation sequences. The algorithm starts by selecting a set of sequences in the space of basic configurations in which the internal structure of condensers and reboilers is explicitly taken into account and extended with the possibility of including divided wall columns (DWC). This first stage is based on separation tasks (except by the DWCs) and therefore it does not provide an actual sequence of columns. In the second stage the best arrangement in N-1 actual columns is performed taking into account operability and mechanical constraints. Finally, for a set of candidate sequences the algorithm try to reduce the number of total columns by considering Kaibel columns, elimination of transfer blocks or columns with vertical partitions. An example illustrate the different steps of the sequential algorithm.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The main subject of this dissertation is packaging, which is an inescapable product in our society nowadays. Every product we consume daily is generally protected and sheltered by a package that visually represents the product – the main feature of packaging. This research aims to assess the importance of packaging today as well as its role in the past, while searching for ways to improve its qualities as a design project. From the sustainability’s perspective, packaging is a factor that must be observed in dealing with its production, use and disposal and that is precisely the point of view that it is explored within this dissertation: packages’ ability of being sustainable and matching more ecological design practices. The main goal of this research is being able to take advantage of the package and its qualities as a selling means and at the same time make it a product that doesn’t harm our planet and the environment. Although packaging is targeted to match trade and economic issues, environmental factors have been addressed more incisively, as those are one of the biggest problems about this matter: the disposal of the package generates the accumulation of waste after the product is consumed. That being said, the challenge is to produce sustainable packaging and also to redefine the concept of packaging itself. Therefore this research intends to look for the link between packaging and sustainability and how that linkage can add value to the trade market and also to our planet’s health and well-being

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Solution approaches based purely on economics do not lead to optimal success – at least, not in the medium to long term. Rather, a sustainable economy requires an equal consideration of the ecological and social dimensions. The green economy concept, or, better said, the green and fair economy concept, is in principle suitable for, if not avoiding an economic and financial crisis as experienced in the last five years, at least moderating its negative effects. The important thing here is to integrate the design of the concept as much as possible at the political, economic and individual level.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Washington, D.C.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Competition Drawing of Design Concept. Ink drawing on tracing paper, initialed, 11x17 inches [from photographic copy by Lance Burgharrdt]

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The concept of the burden of disease, introduced and estimated for a broad range of diseases in the World Bank report of 1993 illustrated that mental and neurological disorders not only entail a higher burden than cancer, but are responsible, in developed and developing countries, for more than 15% of the total burden of all diseases. As a consequence, over the past decade, mental disorders have ranked increasingly highly on the international agenda for health. However, the fact that mental health and nervous system disorders are now high on the international health agenda is by no means a guarantee that the fate of patients suffering from these disorders in developing countries will improve. In most developing countries the treatment gap for mental and neurological disorders is still unacceptably high. To address this problem, an international network of collaborating institutions in low-income countries has been set up. The establishment and the achievements of this network-the International Consortium on Mental Health Policy and Services-are reported. Sixteen institutions in developing countries collaborate (supported by a small number of scientific resource centres in industrialized nations) in projects on applied mental health systems research. Over a two-year period, the network produced the key elements of a national mental health policy; provided tools and methods for assessing a country's current mental health status (context, needs and demands, programmes, services and care and outcomes); established a global network of expertise, i.e., institutions and experts, for use by countries wishing to reform their mental health policy, services and care; and generated guidelines and examples for upgrading mental health policy with due regard to the existing mental health delivery system and demographic, cultural and economic factors.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Network building and exchange of information by people within networks is crucial to the innovation process. Contrary to older models, in social networks the flow of information is noncontinuous and nonlinear. There are critical barriers to information flow that operate in a problematic manner. New models and new analytic tools are needed for these systems. This paper introduces the concept of virtual circuits and draws on recent concepts of network modelling and design to introduce a probabilistic switch theory that can be described using matrices. It can be used to model multistep information flow between people within organisational networks, to provide formal definitions of efficient and balanced networks and to describe distortion of information as it passes along human communication channels. The concept of multi-dimensional information space arises naturally from the use of matrices. The theory and the use of serial diagonal matrices have applications to organisational design and to the modelling of other systems. It is hypothesised that opinion leaders or creative individuals are more likely to emerge at information-rich nodes in networks. A mathematical definition of such nodes is developed and it does not invariably correspond with centrality as defined by early work on networks.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The operation of polymer electrolyte membrane fuel cells (PEMFCs) with dry feeds has been examined with different fuel cell flow channel designs as functions of pressure, temperature and flow rate. Auto-humidified (or self-humidifying) PEMFC operation is improved at higher pressures and low gas velocities where axial dispersion enhances back-mixing of the product water with the dry feed. We demonstrate auto-humidified operation of the channel-less, self-draining fuel cell, based on a stirred tank reactor; data is presented showing auto-humidified operation from 25 to 115 degrees C at 1 and 3 atm. Design and operating requirements are derived for the auto-humidified operation of the channel-less, self-draining fuel cell. The auto-humidified self-draining fuel cell outperforms a fully humidified serpentine flow channel fuel cell at high current densities. The new design offers substantial benefits for simplicity of operation and control including: the ability to self-drain reducing flooding, the ability to uniformly disperse water removing current gradients and the ability to operate on dry feeds eliminating the need for humidifiers. Additionally, the design lends itself well to a modular design concept. (c) 2005 Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Young men with psychotic disorders have persistently poorer outcomes in social functioning when interventions aimed at arresting social isolation are not implemented. Recent literature has indicated that it is important to develop rehabilitation programmes that are based on areas of needs that are identified by the participants. To assist in the design of a group programme, a qualitative (focus group) investigation of the perceptions of young males concerning male roles and identity in today’s society was conducted. The participants were six young males with psychotic disorders who had been referred to an Australian regional rehabilitation service to address poor social functioning and social isolation. Three main themes emerged from the focus groups. These were role models, concept of what is a man, and societal expectations. The findings were used to develop a group programme called Kick’n’On.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The project is working towards building an understanding of the personal interests and experiences of children with the aim of designing appropriate, usable and, most importantly, inspirational educational technology. kidprobe, an adaptation of the technology probe concept, has been used as a lightweight method of gaining contextual information about children's interactions with 'fun' technology. kidprobe has produced design inspiration which focuses primarily on the social and emotional connections children made. The use of kidprobe has generated some important ideas for improving the use of probes with children. It is an important first step in understanding how to effectively adapt probing techniques to inspire the design of technology for children.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

SINNMR (Sonically Induced Narrowing of the Nuclear Magnetic Resonance spectra of solids), is a novel technique that is being developed to enable the routine study of solids by nuclear magnetic resonance spectroscopy. SINNMR aims to narrow the broad resonances that are characteristic of solid state NMR by inducing rapid incoherent motion of solid particles suspended in a support medium, using high frequency ultrasound in the range 2-10 MHz. The width of the normal broad resonances from solids are due to incomplete averaging of several components of the total spin Hamiltonian caused by restrictions placed on molecular motion within a solid. At present Magic Angle Spinning (MAS) NMR is the classical solid state technique used to reduce line broadening, but: this has associated problems, not least of which is the appearance of many spinning side bands which confuse the spectra. It is hoped that SlNNMR will offer a simple alternative, particularly as it does not reveal spinning sidebands The fundamental question concerning whether the use of ultrasound within a cryo-magnet will cause quenching has been investigated with success, as even under the most extreme conditions of power, frequency and irradiator time, the magnet does not quench. The objective of this work is to design and construct a SINNMR probe for use in a super conducting cryo-magnet NMR spectrometer. A cell for such a probe has been constructed and incorporated into an adapted high resolution broadband probe. It has been proved that the cell is capable of causing cavitation, up to 10 MHz, by running a series of ultrasonic reactions within it and observing the reaction products. It was found that the ultrasound was causing the sample to be heated to unacceptable temperatures and this necessitated the incorporation of temperature stabilisation devices. Work has been performed on the investigation of the narrowing of the solid state 23Na spectrum of tri-sodium phosphate using high frequency ultrasound. Work has also been completed on the signal enhancement and T1 reduction of a liquid mixture and a pure compound using ultrasound. Some preliminary "bench" experiments have been completed on a novel ultrasonic device designed to help minimise sample heating. The concept involves passing the ultrasound through a temperature stabilised, liquid filled funnel that has a drum skin on the end that will enable the passage of ultrasound into the sample. Bench experiments have proved that acoustic attenuation is low and that cavitation in the liquid beyond the device is still possible.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The concept of shallow fluidized bed boilers is defined and a preliminary working design for a gas-fired package boiler has been produced. Those areas of the design requiring further study have been specified. Experimental investigations concerning these areas have been carried out. A two-dimensional, conducting paper analog has been developed for the specific purpose of evaluating sheet fins. The analog has been generalised and is presented as a simple means of simulating the general, two-dimensional Helmholtz equation. By recording the transient response of spherical, calorimetric probes when plunged into heated air-fluidized beds, heat transfer coefficients have been measured at bed temperatures up to 1 100°C. A correlation fitting all the data to within ±10% has been obtained. A model of heat transfer to surfaces immersed in high temperature beds has been proposed. The model solutions are, however, only in qualitative agreement with the experimental data. A simple experimental investigation has revealed that the effective, radial, thermal conductivities of shallow fluidized beds are an order of magnitude lower than the axial conductivities. These must, consequently, be taken into account when considering heat transfer to surfaces immersed within fluidized beds. Preliminary work on pre-mixed gas combustion and some further qualitative experiments have been used as the basis for discussing the feasibility of combusting heavy fuel oils within shallow beds. The use of binary beds, within which the fuel could be both gasified and subsequently burnt, is proposed. Finally, the consequences of the experimental studies on the initial design are considered, and suggestions for further work are made.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The concept of an Expert System (ES) has been acknowledged as a very useful tool, but few studies have been carried out in its application to the design of cold rolled sections. This study involves primarily the use of an ES as a tool to improve the design process and to capture the draughtsman's knowledge. Its main purpose is to reduce substantially the time taken to produce a section drawing, thereby facilitating a speedy feedback to the customer. In order to communicate with a draughtsman, it is necessary to use sketches, symbolic representations and numerical data. This increases the complexity of programming an ES, as it is necessary to use a combination of languages so that decisions, calculations, graphical drawings and control of the system can be effected. A production system approach is used and a further step has been taken by introducing an Activator which is an autoexecute operation set up by the ES to operate an external program automatically. To speed up the absorption of new knowledge into the knowledge base, a new Learning System has been constructed. In addition to developing the ES, other software has been written to assist the design process. The section properties software has been introduced to improve the speed and consistency of calculating the section properties. A method of selecting or comparing the most appropriate section for a given specification is also implemented. Simple loading facilities have been introduced to guide the designer as to the loading capacity of the section. This research has concluded that the application of an ES is beneficial and with the activator approach, automated designing can be achieved. On average a complex drawing can be displayed on the screen in about 100 seconds, where over 95% of the initial section design time for repetitive or similar profile can be saved.