541 research outputs found
Technology transfer and sustainable development in emerging economies
No full text(WP 01/03 Clave pdf) This paper aims to show how the process of diffusion of "clean technologies" confronts a variety of forces at the macro level that create systematic, technological and institutional barriers to their adoption. There is abundant literature on the role of technology transfer in the development of emerging economies, but this perspective is clearly new. What needs to be borne in mind is the possibility that the transferred dominant technology may be subject to a techno-institutional lock-in at its source that does not allow the diffusion of environmentally superior alternative technologies.Developing economies, Sustainable development, Techno-institutional lock-in, Technology transfer
Ice-Induced Aircraft Stability Upsets: An experimental investigation to identify linear and non-linear fluid-structure lock-in
No full textResearch related to the impact that war head induced damage had on the aeroelastic integrity of lifting surfaces and in turn the resulting upset of the complete aircraft, prompted a current look at similar aeroelastic events that might be triggered by damage of the aircraft due to icing. This possible aeroelastic impact due to icing damage is not a very commonly explored area of research. Although seldom studied, icing can also significantly impact the aeroelastic stability and hence the overall stability and control of the aircraft. In this latter context, classical flutter events of the lifting surfaces and controls can occur due to ice-induced mass unbalance or control force reversal. Also, a loss of control effectiveness or limit cycle oscillations of the controls and lifting surfaces may appear, due to significant time dependent drag forces introduced by separated flow conditions imposed by the ice accumulation. Two commonly observed ice-induced upset scenarios were selected to investigate. The first scenario involves an elevator limit cycle oscillation and a resulting loss of elevator control effectiveness. The second upset is related to a violent wing rock or Dutch roll instability. In both proposed ice-induced upsets, lock-in mechanisms of two unsteady events occur, (1) the ice-induced unsteady flow field and (2) the unsteady structural acceleration of the aircraft. A wind tunnel study is employed to investigate the lock-in mechanisms of the structural acceleration and the unsteady flow field induced by ice accumulation that is only present on the elevator horn balance leading edges. The purpose is to determine the linear and non-linear coupling mechanisms between these events. An experimental data set has been obtained where the unsteady, ice-induced, flow field and the acceleration of a 1:10 scale, reduced-stiffness, aircraft model is synchronously acquired using pressure transducers and accelerometers, respectively. The experiments are performed at various angles of attack of the aircraft, _p, with and without simulated ice accumulation on the elevator horn balance leading edges and with various settings of the elevator deflection angle, _. Statistical signal processing techniques, that are able to compute linear and quadratic coherence spectra, are presented in this thesis work and are applied in the pressure-acceleration coherence study. The first-order processing technique, based on the well-known linear coherence spectrum, revealed a low-frequency lock-in (f = 6Hz, _p > 7_) for the case where ice accumulation was simulated on the leading edges of the horn balances, while no lock-in was observed without ice simulations. This indicates that violent aircraft motions can indeed be a result from the ice-induced flow field over the horn balances. Although a reduced-stiffness aircraft model was used in the experimental setup, and thus the quantitative results are not translatable to the full-scale case, the identification of this linear lock-in mechanism indicates that their is a significant chance that similar lock-in mechanisms occur in full-scale flight applications. An attempt to identify the quadratic relations between the two unsteady systems was performed by employing higher-order statistical signal processing based on a non-orthogonal, secondorder, single-input/output (I/O) Volterra model. Due to current limitations, related to the implementation of this technique, no physical interpretations could be done based on the higher-order coherences. Recommendations are given to improve the identification capability of this higher-order technique, which might become a powerful identification and estimation tool in (experimental) fluid dynamics.Aerospace Engineerin
Conceptual design of the Guard Lock for Strandeiland Flood Defence
No full textIn response to Amsterdam’s housing shortage, IJburg on the east side of Amsterdam, is being devel- oped. IJburg consists of six artificial islands in total on which about 20,000 homes for 50,000 residents are being built. Strandeiland (Beach island in English), located in the lake called IJmeer, is one of these artificial islands which is currently being developed to accommodate approximately 20,000 residents. This project aims to introduce approximately 8,000 homes. However, the establishment of Strandei- land presents hydraulic safety concerns, especially with the presence of extreme low water levels and fluctuations due to wind set-up and set-down.Strandeiland will feature an inland water with high recreational value for residents. This inland water will also provide access for recreational boating. Wind set-down and set-up can create extreme water level differences in this inner water. These water level differences are unfavorable and create danger to the stability of the island. These fluctuations pose a severe challenge to the stability and functionality of the island’s water infrastructure. Two primary solutions were evaluated: the adaptation of the inner quay wall or the implementation of a guard lock. Making the inner quay wall suitable for the water level differences brings several implications:• Restrictions on utilities: Because the inner quay wall would be marked as primary flood defence, no pipes and cables would be allowed inside the wall.• Design constraints: When the quay wall serves as the primary flood defence, construction on its inner slope and tree planting is prohibited. This would negatively impact the aesthetics of the waterfront and limit the housing construction space.• Increased height requirements: The inner wall has to be higher according to primary flood defence regulations, this would escalate construction costs.• Higher strength sheet piles: A higher strength of sheet piles has to be used to withstand ex- tremely low water levels which would also lead to escalating construction costs.Adapting the Inner Quay Wall, while feasible, introduces significant design and functional constraints. Because of these constraints, this option is less desirable and implementing a guard lock is the favor- able solution to solve the water level fluctuations.The guard lock as part of the primary flood defence controls extreme water level variations, ensuring Strandeiland’s water infrastructure’s integrity. The Guard Lock not only modifies the primary flood de- fence location, reducing its length considerably but also mitigates the constraints associated with an adapted inner quay wall. The water level spread is set from the program of requirements at NAP -0.6 meters and NAP +0.1. The current estimate is that this will require the lock to close 10 times a year, which is considered acceptable. A movable bridge is integrated which functions both as a neighbor- hood connector and a part of the beachside boulevard.The main objective during the design phase is to develop a Guard Lock concept for Strandeiland that facilitates the management of water level fluctuations while accounting for potential failure mechanisms. Dimensions for the Guard Lock were determined based on the standard vessel, leading to lock cham- bers measuring 22 meters in length and 7.6 meters in width. Anticipating approximately ten annual guard lock closures in extreme scenarios, the F/E system is not included initially. To facilitate a possi- ble future inclusion of a F/E system, the core dimensions are based on two lock chambers resulting in an overall structural length of 36.46 meters.Different gate designs were evaluated for the guard lock design: Mitre Gates, Rolling/Sliding gates, Lift gate (submersible), Lift gate (upward direction), Radial gates and Single-leaf gates. The first step was to check whether the different gate types were suitable for the situation in which Strandeiland is, looking at space and and vertical clearance. The lift gate in upward direction and the rolling sliding gate were considered unsuitable for this purpose. The elevator gate limits vertical clearance and the rolling sliding gates takes to much space besides to the lock. The remaining gate types were measured in a multi-criteria analysis, which resulted in a double set of mitre gates ensuring both-way retention. Because of safety and energy efficiency, but especially because of local knowledge and possibilities for maintenance, electromechanical driving mechanisms were chosen for the gates instead of an hydraulic driving mechanism.Key design elements of the core construction of the guard lock consist of the concrete structure con- sisting of the walls and the floor slab. After performing the stability checks for the bearing capacity, overturning and piping the strength calculations are done for the floor slab and the walls of the con- crete structure. The reinforcement calculations are providing detailed reinforcements for the floor slab and walls.The pile foundation is another main component of the structure. The vertical bearing capacity check indicates that no pile foundation is needed, but because non uniform settlement is expected a pile foun- dation will be included. Three different layers were evaluated to check which one was the best fit for the guard lock of Strandeiland. As the first layer is determined to be suitable to bear the load of the structure, this layer has been used. This is the most cost effective for the pile foundation design, as there is less material needed for the pile foundation design. The calculations show that 45 piles with an diameter of 0.8 m each satisfies the need to prevent non-uniform settlements under the structure.The last component which has been determined is the gate height. The process for determining gate height utilized Reliability-Based Design (RBD) principles. Reliability-Based Design (RBD) ensures the gate height is optimal in terms of cost and safety. In this way an effective design for the gate height is obtained. A comprehensive fault tree analysis, combined with a Monte Carlo analysis, established the final gate height at 5.05 meters corresponding to NAP + 1.55 m, as shown in Figure 1.Civil Engineering | Hydraulic Engineerin
How architecture influences intellectual property lock-in
No full textThesis: Ph. D. in Engineering Systems, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections."June 2017." Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 237-247).Intellectual property lock-in is a wicked problem particularly pervasive under monopsony market structures, such as the Department of Defense (DoD). However, little research exists on the mechanisms of action that induce intellectual property lock-in. This work postulates the conjuncture of architecture and intellectual property is one such mechanism of action and erects a research methodology to investigate this link. This dissertation began with a review of literature, which revealed more research is needed into basic trends or estimates of magnitude for intellectual property lock-in. To quantitatively frame the magnitude of the problem an investigation was conducted into all DoD contracts for the last eight fiscal years to establish bounds. These results were used to formulate a conceptual model of the problem and suggest the concept of intellectual property architecture, which is the conjuncture of architecture and intellectual property. To investigate links between intellectual property architecture and lock-in, an intermediate-N fuzzy-set Qualitative Comparative Analysis research approach was formulated and executed using 14 DoD software cases representing over 34 million lines of code. The model used three input conditions: high quality technical architecture, accessible intellectual property architecture, and unlimited rights to study the avoidance of lock-in. The fuzzy-set Qualitative Comparative Analysis concluded intellectual property architecture or unlimited rights were quasi-necessary conditions for the avoidance of lock-in. Additionally the model yielded both a five condition conservative expression and two condition parsimonious expression for sufficient conditions. From those expressions, this research concludes three direct findings. First, intellectual property architecture is an empirically supported mechanism of action for the avoidance of lock-in. Implying, intellectual property architecture, absent any other explanatory conditions, is sufficient to avoid lock-in. Second, the research herein finds evidence to support a novel taxonomy of intellectual property architectures. Allowing practitioners to understand potential trade-offs between architecture and intellectual property lock-in. Third, intellectual property architecture or unlimited rights is a theoretically supported expression for the avoidance of lock-in. This finding implies that as few as two conditions are required to understand whether a case may, or may not, avoid lock-in.by Christopher W. Berardi.Ph. D. in Engineering System
Design and analysis of high performance low noise oscillators and phase lock loops
No full textThe design and implementation of high purity, high speed and power efficient clock generation Integrated Circuits continue to be one the greatest challenges facing IC designers today. In order to address this challenge, this thesis considers the modeling and design of two fundamental clock generation circuits – the VCO and PLL.An improved ring oscillator topology is proposed which has the advantage of an ultra wide tuning range. A novel noise aware ring oscillator model is also proposed which links the noise performance of the oscillator to its transistor dimensions giving insight to the design procedure. The use of this VCO model in a noise-aware PLL model allows the trade-off between noise performance and the loop bandwidth to be quantified accurately. From further analysis of the proposed PLL model, a novel PLL structure has been designed which is extremely successful at reference spur suppression.Simulation results based on the proposed model and foundry BSIM3v3 models are provided for all the VCO and PLL designs. To validate the proposed VCO topology and VCO model, two prototype chips have been fabricated and measured results show close agreement with theoretical analysis and simulatio
Governance of Environment-Enhancing Technical change - past experiences and suggestions for improvement
No full textThere is much talk about environmental policies being faulty. Past policies are being criticisedfor failing to achieve environmental goals (the environmentalist complaint), for being overlyexpensive (the industrialist complaint) and for failing to encourage innovation and dynamicefficiency (the complaint of economists dealing with innovation). This paper looks at theinnovation and technology adoption effects of past environmental policies. It finds indeed fewexamples of environmental policies that stimulated innovation. The common technologyresponse is the use of expensive end-of-pipe solutions and incremental process changesoffering limited environmental gains. This begs the question: why did the policies fail topromote more radical innovation and dynamic efficiency? One explanation—well-recognisedin the economic literature—is the capture of government policies by special interests. Thispaper offers a second explanation—based on innovation and technology adoption studies—which says that in order to have a decisive and socially beneficial influence policy instrumentsmust be fine-tuned to the circumstances in which sociotechnical change processes occur and tipthe balance. Within this alternative view, the starting point of government interventions is thecapabilities, interests, interdependencies and games of social actors around an environmentalproblem instead of the set of environmental policy instruments for achieving an environmentalgoal. The paper sees a need for government authorities to be explicitly concerned with technicalchange (rather than implicitly through a change in the economic frame conditions) and to beconcerned with institutional arrangements beyond the choice of policy instruments, and act as achange agent. This requires different roles for policy makers: that of a sponsor, planner,regulator, matchmaker, alignment actor and ‘creative game regulator’. The paper offers twoperspectives on environmental policy: an instrument one and a modulation one. The latter isespecially important for promoting innovation and bringing about radical change, somethingwhich is very difficult with traditional regulatory instruments. Instruments for promotingenvironment-enhancing technical change are appraised and suggestions are offered for thepurposes for which different policy instruments may be used in differing economic contexts.environmental economics ;
Workshop receipts, for manufacturers and scientific amateurs.
No full text[First series] by Ernest Spon, 1885; 2d series, by Robert Haldane, 1883; 3d-4th series, by C. G. Warnford Lock, 1884-1885; 5th series, 1892, no author given.On cover: Spon's workshop receipts for manufacturers, mechanics and scientific amateurs.v.1. Acetylene lighting--Drying.--v.2. Dyes and dyeing--Japanning.--v.3. Joint pipes--Pumps.--v.4. Rainwater separator--Wire ropes.Mode of access: Internet
Use of a visceral protective layer prevents fistula development in open abdomen therapy: results from the European Hernia Society Open Abdomen Registry
No full textTechno-economic transition towards a hydrogen economy
No full textPhDThe research conducted is in the field of innovation and focuses on the UK energy sector. The key theme of the study is the transition towards a hydrogen economy with fuel cell technologies at the epicentre and takes into account the relevant scientific, technological, economic and policy issues. In order to provide an understanding of the factors that affect techno-economic transitions to alternative energy systems, the thesis investigates the historical transition processes such as the transition to electrification in the early 1900s and recent transitions to CCGT and renewable energy systems (wind, biofuels and solar) that have taken place since the late 1980s. As the developmental status of hydrogen technologies lay at the heart of these transitions, a thorough analysis of the hydrogen and fuel cell technologies, the R&D requirements, and innovations required in different scientific fields (including materials science) to develop these technologies is conducted. At the same time, as other factors such as sustainability, climate change and security of supply concerns can greatly affect the direction of the transition processes, that includes R&D activities and investment in alternative energy technologies, an overview of these factors is also provided. The analysis employs a new theoretical framework that combines two well established theories in the literature, Techno-economic Transitions and Large Technological Systems. By using this new framework, the technological transition towards a hydrogen energy system can be analysed at three levels, (global, national and local). The analysis is narrowed down to the local level in order to determine the timing of a transition in London and how it can form the foundation for a wider a transition at the national level based on alternative technologies
Critical Care Setting of Bedside Positioning of Electromagnetically Guided Nasointestinal Tubes
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