A structure excited by a DC motor of limited power supply and controlled by a pendulum like device

In this paper, a mathematical model is derived via Lagrange's Equation for a shear building structure that acts as a foundation of a non-ideal direct current electric motor, controlled by a mass loose inside a circular carving. Non-ideal sources of vibrations of structures are those whose characteristics are coupled to the motion of the structure, not being a function of time only as in the ideal case. Thus, in this case, an additional equation of motion is written, related to the motor rotation, coupled to the equation describing the horizontal motion of the shear building. This kind of problem can lead to the so-called Sommerfeld effect: steady state frequencies of the motor will usually increase as more power (voltage) is given to it in a step-by-step fashion. When a resonance condition with the structure is reached, the better part of this energy is consumed to generate large amplitude vibrations of the foundation without sensible change of the motor frequency as before. If additional increase steps in voltage are made, one may reach a situation where the rotor will jump to higher rotation regimes, no steady states being stable in between. As a device of passive control of both large amplitude vibrations and the Sommerfeld effect, a scheme is proposed using a point mass free to bounce back and forth inside a circular carving in the suspended mass of the structure. Numerical simulations of the model are also presented Copyright © 2007 by ASME.

Proposals for curbing the boom-bust cycle in the supply of capital to emerging markets

Includes bibliography

Dynamics of a piecewise-linear oscillator with limited power supply

We discuss dynamics of a vibro-impact system consisting of a cart with an piecewise-linear restoring force, which vibrates under driving by a source with limited power supply. From the point of view of dynamical systems, vibro-impact systems exhibit a rich variety of phenomena, particularly chaotic motion. In our analyzes, we use bifurcation diagrams, basins of attractions, identifying several non-linear phenomena, such as chaotic regimes, crises, intermittent mechanisms, and coexistence of attractors with complex basins of attraction. © 2009 by ASME.

An investigations on local and global behavior of a (SMA) oscillator of 3 - DOF driven by a limited power supply

SMART material systems offer great possibilities in terms of providing novel and economical solutions to engineering problems. The technological advantages of these materials over traditional ones are due to their unique microstructure and molecular properties. Smart materials such as shape memory alloys (SMA), has been used in such diverse areas of engineering science, nowadays. In this paper, we present a numerical investigation of the dynamics interaction of a nonideal structure (NIS). We analyze the phenomenon of the passage through resonance region in the steady state processes. We remarked that this kind of problem can lead to the so-called Sommerfeld effect: steady state frequencies of the DC motor will usually increase as more power (voltage) is given to it in a step-by-step fashion. When a resonance condition with the structure it is reached, the better part of this energy it is consumed to generate large amplitude vibrations of the foundation without sensible change of the motor frequency as before. The results obtained by using numerical simulations are discussed in details. Copyright © 2009 by ASME.

Optimal contract pricing of distributed generation under a competitive framework

A bilevel programming approach for the optimal contract pricing of distributed generation (DG) in distribution networks is presented. The outer optimization problem corresponds to the owner of the DG who must decide the contract price that would maximize his profits. The inner optimization problem corresponds to the distribution company (DisCo), which procures the minimization of the payments incurred in attending the expected demand while satisfying network constraints. The meet the expected demand the DisCo can purchase energy either form the transmission network through the substations or form the DG units within its network. The inner optimization problem is substituted by its Karush- Kuhn-Tucker optimality conditions, turning the bilevel programming problem into an equivalent single-level nonlinear programming problem which is solved using commercially available software. © 2010 IEEE.

E-business innovation and customs renovation for secure supply chain management

Includes bibliography

Fertility and female labour supply in Latin America: new causal evidence

Includes bibliography

Measuring supply chain management practices

Purpose: This paper aims to perform an empirical investigation about the constructs and indicators of the supply chain management practices framework. Design/methodology/approach: The measuring framework proposed is based on a survey that was carried out on 107 Brazilian companies. Statistical techniques were employed to verify, validate, and test the reliability of the constructs and their indicators. To validate this framework principal component analysis and structural equation modeling techniques were used. Findings: In general, previous studies suggest six constructs for measuring the supply chain management practices framework. However, in this study a framework was achieved with four constructs of supply chain management practices, namely, supply chain (SC) integration for production planning and control (PPC) support, information sharing about products and targeting strategies, strategic relationship with customer and supplier, and support customer order. This framework has adequate levels of validity and reliability. Research limitations/implications: The main limitation of this study was that only a small sample of companies in a single sector and country were surveyed, and therefore there needs to be further research considering the special conditions in other countries. Originality/value: This study investigated statistically set indicators to discuss the topic supply chain management practices. The framework obtained has good quality of validity and reliability indicators. Thus, an alternative framework has been added to measure supply chain management practices, which is currently a popular topic in the supply chain mainstream literature. Both defined constructs and the validated indicators can be used in other studies on supply chain management. © Emerald Group Publishing Limited.

Supply chain risk management: An exploratory research in Brazilian aerospace industry

This paper aimed to analyse supply chain risk factors in aerospace industry. It was conducted an exploratory research at an important Brazilian aerospace company. This company has a major role at the global aerospace industry. Senior managers assessed risk factors such as quality, productivity, supply chain, business strategy, organisation, environmental and natural political, indicators, product management, and information system. Analytic hierarchy process was applied to prioritise these factors. The most relevant were quality and productivity. Copyright © 2011 Inderscience Enterprises Ltd.

Drinking water supply and sanitation services on the threshold of the XXI century

Includes bibliography

Factors affecting the adoption of supply chain management practices: Evidence from the Brazilian electro-electronic sector

This study on the factors affecting the adoption of supply chain management (SCM) practices develops four hypotheses based on a literature review, and tests them using survey data of Brazilian electro-electronic firms. The results reveal the big picture of the SCM practices in the sector and suggest that contextual factors such as size, position and bargaining power affect the adoption of SCM practices, which are also more customer oriented. Sector characteristics are very important in analysing SCM practices. Contrary to the findings of literature, the relationship between competitive priorities and SCM practices was not supported statistically. © 2011.

Operations strategy and supply chain management: A Brazilian case study

The objective of this study is to understand how an assembly company, that is considered a focal company in the chain of Brazilian white goods sector, can influence the supply chain management established with its first tier suppliers. This is an exploratory qualitative study in which the information was gathered through direct observations, documents' retention, and data from interviews held with management-level employees of the sales and product development areas of the focal company and of the production area of the suppliers' companies. This study indicates that the operations strategy of the focal company influences the supply chain management and that the common business processes shared by its suppliers are a way to verify the truth of such statement. The suppliers cooperate closely with the focal company when complementing their business processes and consequently supporting the company to pursue its operations strategy. A set of mechanisms to aid the comprehension of how the operations strategy can affect the business processes and therefore to achieve the result of this research were adopted. © EuroJournals Publishing, Inc. 2012.

Employment, growth and reforms in Jamaica

Includes bibliography

Supply Chain Management practices in the electro-electronics sector in Brazil: Evolutionary approach, information technology adoption and management actions

This paper examines the current level of adoption of Supply Chain Management (SCM) practices in the electro-electronic sector in Brazil and aims to identify the management and Information Technology (IT) actions that have been implemented to support the adoption of those practices. An e-mail survey was conducted. Descriptive statistics techniques were employed for data analysis. This study makes contributions to the electro-electronics sector and to the topics related to SCM, such as identifi cation and level of adoption of SCM practices. Another contribution of this research is the investigation of whether approaches such as Enterprise Resources Planning (ERP), Workshop with Customers, Electronic Data Interchange (EDI), Workshop with Suppliers and electronic Kanban are commonly used to support SCM practices. So far, this is the fi rst research on SCM practices in the electro-electronics sector in Brazil. Copyright © 2012 Inderscience Enterprises Ltd.

Agua potable y saneamiento ambiental en América Latina, 1981-1990 = Drinking water supply and sanitation in Latin America, 1981-1990

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