86 research outputs found
Metal Organic Frameworks for Gas-phase Capacitive Sensing
No full textOLD ChemE/Organic Materials and Interface
Agricultural trade liberalization in the Uruguay Round : one step forward, one step back?
No full textAfter evaluating the Uruguay Round's impact on agriculture and border protection in the next decade, the author concludes that while there was significant reform of the rules - particularly the conversion of nontariff barriers into tariffs and the reduction and binding of all tariffs - in practice, trade will probably be liberalized less than expected. The objective of the Round was to reverse protectionism and remove trade distortions. This may not be achieved in practice, at least not until further reductions are carried out in future rounds of negotiations. The major exception to this conclusion is in high-income Asian countries, where protection for major commodities will be significantly reduced. The tariffication and binding of all tariffs on agricultural products represents a significant step forward. Liberalization is implicit because countries are prohhibited from arbitrarily raising tariffs to new higher levels. But many of the newly established tariffs are so high in many countries as to effectively prohibit trade. Patterns of liberalization vary considerably by commodity and by country. Generally, the extent of liberalization was diminished by binding tariffs to the base period of 1986-88, when border protection was at a high point. In most OECD countries, this was worsened by"dirty tariffication:"the new base tariffs offered even greater protection than the nontariff barriers they replaced. Even after the commitments to tariff reductions in the Round, the ad valorem measure of the final binding tariffs will remain higher than the average rate of protection in 1982-93. A number of developing countries in East Asia, Latin America, and the Middle East chose to lock in prior liberalization efforts on some products. But for most commodities, there will be little actual liberalization, since most developing countries chose to bind their tariffs at a maximum level. Even when countries reduced already-bound rates, bound tariffs remained significantly higher than current applied rates, giving countries the flexibility to raise tariffs later. The high level of bound tariffs may allow countries to apply variable tariffs below the bound level, thus failing to stabilize tariffs and improve market access. Moreover, the Round did not touch many of the worst distortions in developing countries, such as import subsidies, export taxes, state-trading monopolies, and domestic policies that implicitly tax agriculture.Trade Policy,Environmental Economics&Policies,Economic Theory&Research,Export Competitiveness,Rules of Origin,Trade Policy,Rules of Origin,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Environmental Economics&Policies,Economic Theory&Research
Design of Low-Threshold Comparator for Improved Timing-Resolution Analog/Digital SiPM
No full textCoincidence time resolution (CTR) in time-of-flight (TOF) positron emission tomography (PET) determines the signal-to-noise ratio (SNR) in iterative image reconstruction algorithms. In PET detectors, the photodetector's single-photon timing resolution (SPTR) influences the CTR by adding uncertainty to the single photoelectron time-of-arrivals. This effect can be modelled as the convolution of the scintillation pulse shape function and the total photodetector jitter at single-photon level, before following an order statistics process. Particularly in Cherenkov-based PET detectors, SPTR has a direct impacton the CTR due to the low number of detected photons. In this thesis, the research is focussed on the design of low thresh-old comparators for two specific purposes in PET. Firstly, the design of in-pixel (SPAD-cell) low-threshold comparator that improves SPAD jitter at the pixel level, since it allows the detection of photo-electron triggered avalanche at the earliest possible time, thus minimizing statistical fluctuations. The design is targeted for Cherenkov-based PET, where improvement in SPTR directly results in improvement of CTR. Secondly, for the integration of analog silicon photomultiplier (A-SiPM) on-chip. Such integration helps in realizing a high Photon Detection Effciency (PDE) and low Dark Count Rate (DCR) A-SiPM with integrated readout electronics. A high speed comparator with a direct connection to the fast terminal of A-SiPM has been realized.Electrical Engineering | Microelectronic
Sachdeva’s Ark: The imminent deluge of space crimes
No full textDeviation from accepted social standards of living has been a concern since the inception of society. Society, through its laws, has set a threshold of deviations, the crossing of which, whatsoever be the motivation for such imprudence, becomes behaviour that warrant attention and correction. G S Sachdeva, the author of the book under review, echoes this social truth about human nature, in the same vein and grandeur as David Hume, at the outset of his exposition, ‘Humans are after all human and wherever they go (…) And under stress or provocation, these [their human instincts] may burst open, criminally’ (p. vii). Does Sachdeva maintain this Humeanist elegance and eloquence that he displays at the start of his discourse through the rest of the book? In fact, Sachdeva, of everything he is and he is not, is thoroughly philosophical in his approach to things, which manifests as an irresistible desire to explore meanings and to provide explanations for the same. That perhaps qualifies him as a Humeanist
Effect of the optimisation time interval on the performance of mobile networks
No full textThis thesis project researches the effect of the optimisation time interval on the performance of a self-optimised mobile network. The goal of the thesis is to ascertain if there exists an optimal time interval for the self-optimisation of the KPN network, and what that interval is. In order to research this question, the project uses data from the KPN network as input, and sets up a simulation study in MATLAB. Two areas in the Netherlands are considered in this study – Friesland and Purmerend. The self-optimisation of the network is carried out through the modification of three optimisation parameters – antenna tilt, RS power, and Cell Individual Offset. The scope of the study is limited to LTE in the downlink, for the 800 MHz band. The bandwidth used in this study is 10 MHz. The performance of the mobile network has been studied using KPIs such as 10th throughput percentile, coverage failure rate, call drop rate, and load. In the end, the study analyses the results for each area, for the self-optimisation carried out by modifying the three parameters over several different optimisation time intervals, and discusses their impact on the performance of the network. A comparison has also been drawn between the performance of a self-optimised network and an un-optimised network, to highlight the gains achieved with SON. Finally, recommendations are made regarding a suitable time interval, and a relative comparison between suitability of the three optimisation parameters has been drawn. The study finds that a suitable time interval for optimisation does exist, and is 240 minutes, for both the simulation areas. The study finds RS power to be the most suitable parameter for self-optimisation, in both the areas. However, the research runs into some unexpected results with respect to the optimisations using tilt angle, and has been discussed in detail in the report. Significant gains are observed with SON, as compared to the case of ‘No SON’ or an un-optimised network. Electrical Engineering | Network Architectures and Service
Techno-Economic feasibility analysis of Solid-Oxide Fuel Cell-Gas Turbine based hybrid propulsion system fueled by Hydrogen: How a Solid-Oxide Fuel Cell can impact the performance of the propulsion system and the economics of the aircraft
No full textThe world is moving towards sustainability and there is immense pressure on Aerospace Industry to reduce its emissions to contribute to a carbon-neutral world. However, maturing gas turbine technology is a big bottleneck towards this goal and hence, this project focuses on the technical and economic feasibility of a new type of propulsion system, called Solid-Oxide Fuel Cell- Gas Turbine or SOFC-GT hybrid propulsion system. SOFC- GT, even though being a low TRL technology, has the potential to reduce fuel consumption, emissions, and operation costs, making it a suitable candidate for a future propulsion system.This research concludes that in order to achieve the full potential of the SOFC-GT hybrid, engine parameters like BPR, FPR and cooling air requirements need to be changed. The Thrust-Specific Fuel Consumption (TSFC) for the propulsion system has decreased by 6.03% and 19.89% for 1 MW and 4 MW fuel cell power output in Off-Design (Cruise) condition. Along with this, core mass flow rate or size, cooling air requirement and Turbine Inlet Temperature for Cruise condition has decreased. The emission results show that the NOx emissions have been reduced by 29.11% and 78.05% respectively. Sensitivity analysis shows that the thermodynamic efficiency is most sensitive to engine parameters but the impact of fuel cell parameters is increasing as the fuel cell power output is increased. The economic analysis done in this study shows that the SOFC-GT hybrid is not feasible for the commercially available fuel cell because of the substantial increase in weight of the propulsion system. However, the propulsion system will become feasible at the fuel cell system specific power of 2.30 kW/kg and 2.10 kW/kg for no emission tax and highest emission tax scenario respectively at a fuel price of $ 6/kg. Along with this, increasing the fuel cell power output leads to the increase in required specific power for fuel cell or has a negative impact on the overall economics. The overall economics of the aircraft is most sensitive to aircraft parameters but increasing the fuel cell power output decreases sensitivity substantially. In the end, the emission has a low impact on the overall economics of the aircraft. This research shows that it is possible to integrate a SOFC with the turbofan if the fuel cell technology improves in the future. Along with this, the research provides multiple novel methodologies for technical and economic analysis of the SOFC-GT hybrid.Aerospace Engineering | Flight Performance and Propulsio
Detection and Tracking of a Fast-Moving Object in Squash using a Low-Cost Approach
No full textAdvancement in technology has given rise to the need for technology to be utilized in extracting meaningful game-play information from sports. To do so in a ball-game like squash, the prime objective is to perform ball-tracking in an adequate and efficient manner. In squash, ball-tracking is complex due to the small size of the ball, the high-speed movement and constant occlusion due to the continuous movement of the players. The current state-of-the-art ball tracking methods use high-speed cameras along with high-computation power resources to solve these problems in similar sports such as tennis. The aim of this thesis is to solve the challenges in ball-tracking for squash using a low-cost approach with low-computation power resources and a single camera view. A ball-detection system with a high-accuracy and a ball-tracking system which can optimally tackle the problem of occlusion is developed using computer-vision techniques and by utilizing the cues from the game itself. The implementation is carried out on a Raspberry-Pi which is characterized as a low-computation platform with an Arm Cortex-A53 processor. The results show that the tracking-problem can be solved using a low-cost approach for the challenging scenarios that are present in squash. The 2D trajectory of the ball generated as a result can be used for various applications such as line-calling, shot analysis and game analysis.Electrical Engineering | Embedded System
Hungary's bankruptcy experience, 1992-93
No full textHungary adopted a tough new bankruptcy law in late 1991 that took effect on January 1, 1992. It required managers of firms with arrears over 90 days to any creditor to file for either reorganization or liquidation within eight days (the so-called"automatic trigger") and provided a rather sympathetic framework in which to do so. The result: since January 1992, more than 25,000 cases have been filed - far beyond lawmakers'expectations. Both positive and negative views about the law have been expressed, but details about how the process has actually worked have been scarce. The authors help fill this information gap by providing detailed data on a randomly selected stratified sample of actual cases filed in 1992-93, supplemented by information gained through interviews with judges, liquidations, and firms involved in bankruptcy. Their conclusions are as follows. First, the bankruptcy process appears to have had some degree of economic logic in 1992 and 1993. Better firms were more likely to enter and emerge"successfully"from reorganization, while worse firms were more likely either to fail in reorganization or to file directly for liquidation. Second, judicial reorganization need not be slow and costly. The first wave of reorganizations was handled surprisingly quickly, especially considering the sheer number of cases, the novelty of the process, and the shortage of trained judges. This quickness was possible largely because of the decentralized design of the process. Once the court approved a case, the court had little role. (Amendments added in 1993 may have made the process more bureaucratic and expensive). Third, in this sample, major delays occurred not in reorganization but in liquidation. Creditors will do almost anything to avoid filing for liquidation, and once firms enter liquidation they are still likely to be kept alive indefinitely. In the end, this lack of a viable creditor-led"exit"and debt collection mechanism harms firms by increasing the cost and reducing the flow of credit. Fourth, although the bankruptcy process displays some degree of economic logic, one should not assume that it operates as a similar law would in a market economy. In particular, a likely source of private gain in Hungary appears to be asset or other value diversion (or"value-stripping) before bankruptcy. Fifth, the main need is to strengthen the incentives of creditors to monitor the process closely and to improve their ability to do so.Banks&Banking Reform,International Terrorism&Counterterrorism,Strategic Debt Management,Small Scale Enterprise,Small and Medium Size Enterprises,Banks&Banking Reform,Strategic Debt Management,Legal Products,International Terrorism&Counterterrorism,Economic Theory&Research
Impact of Turning Induced Shape Deformations on Aerodynamic Performance of Leading Edge Inflatable Kites: Master Thesis
No full textWith growing energy demands and a need to switch to a sustainable source of energy key stakeholders are considering the use of high altitude wind energy systems. TU Delft and its start up company kitepower are key stakeholders investigating the commercial viability of this technology. With this goal the research group has developed several kite systems capable of accessing high altitude winds. It is believed that the low investment cost and high performance of kites could lead to a lower cost of energy. Concepts currently being considered involve a leading edge inflatable (LEI) kite that is controlled by an on-board control unit and is connected to a ground-based generator. Once the kite is deployed to the required altitude it enters a power generation stage where it is flown in a figure eight routine. This routine is controlled by the on-board control unit that pulls on tethers that are connected to the tip of the kite. This process is followed by a retraction phase where the kite is pulled back in. The goal of the system is to maximize energy production in the generation phase while limiting the energy consumed in the retraction phase. It is critical to assess and improve the kite design and its performance at all stages of operation such that the net power production can be maximized. While significant advancements have been made into the performance for normal flight there is a lack of research on the aerodynamic performance when there is control input to initiate a turn. The shape of the kite and the high angle of attack at which the kite is flown results in complex flow behavior involving separation, flow vortices, flow reattachment etc. This poses several challenges to maintain accuracy. A computational approach involving a steady-state Reynolds-averaged Navier Stoke (RANS) simulation is believed to be a computationally viable mode of analysis to capture the flow behavior. This thesis details the approach used to improve results attained using this method and understand the influence of deformations associated with control inputs on the aerodynamic performance of the kite. A control input is simulated using a finite element model (FEM) with the Abaqus software by reducing the length of the right steering and increasing the length of the left steering line by 0.5 m. This results in the right side reducing its curvature and being pulled towards the kite control unit (KCU). Whilst on the left side the bridle lines are less tensed, leading to an increase in curvature. The turning performance is governed by the offset and variations in magnitudes of forces. Meshes are generated that attempts to minimize geometry alterations whilst still maintaining high quality. The influence of boundary layer parameters are investigated. A trade-off is made where the influence of key parameters on accuracy and computational time is evaluated; where applicable improvements are made. Both the global as well as the local parameters of the kite in normal as well as turning orientation are analyzed. The results show that control induced deformations lead to a percentage reduction in the lift, whilst the effect on the drag is minimal. It is further seen that the kite initiates stall at an angle of approximately 40 degrees. The stall behavior is initiated at the mid-span of the kite and gradually moves to the tip. The turning performance is measured by looking at the yaw moment. The magnitude of this parameter is linked to the offset and magnitude in force vectors at the tip. Due to the delayed stall at the tips, it is observed that the yaw moment increases beyond 40 degrees. Accuracy issues using this method were seen when performing a validation study on a profile similar to that of the kite. These issues could be due to limitations of the method or potential errors in the reference study. It is recommended to reevaluate the validation study before using this method for detailed flow analysis. It is concluded, that in order to fully trust the relevance of the results, one would have to have to conduct a validation study. However the method’s ability to address non-linear flow effects within a limited time frame makes it a viable option for design optimization/system modelling.Aerospace Engineerin
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