Minimum Modification Research Articles

Software Applications for Runoff Hydrological Assessment

Natural Resource Conservation Service (NRCS) hydrology techniques are based upon unit hydrograph theory and the runoff curve number method of calculating direct runoff from the rainfall occurring over specified areas (National Engineering Handbook, Part 630, Hydrology, NEH-630.10 and 630.16). The Soil Conservation Service (SCS) and the Agricultural Research Service (ARS) in United States of America developed the supporting theory and verification studies for these since the 1940’s and 1950’s. In the beginning, all necessary computations were done by hand or by calculators and an analysis of a sizeable watershed typically took weeks or months. Since ’80, they succeeded to develop computer programs to reduce the calculation time and allow analysis of complex sub-watershed systems. The software application has been developed all these years, adding new features and capabilities or modifications trying to be updated with the latest new computer technologies. The present paper presents three software applications developed for watershed hydrology, especially to calculate and analyze storm runoff volume, peak rate of discharge, and storage volumes for storm water management structures. The purpose of the analysis is to determine the application capabilities and limitations in order to use them in the specific Romanian conditions, with minimum modifications and adaptations.

Optimal Generator Scheduling using Probabilistic Demand Scenarios

We have developed a new method to determine an optimal generator scheduling using probabilistic demand scenarios. The demand scenarios are created statistically as a set of load curves by the past demand data. Covariance matrix is used to reconstruct the distribution of the demand scenarios. Unit commitment calculation is executed for each demand scenario and the operation cost is estimated. Optimal generator scheduling is selected by the expected value of the unit price with including the additional cost to compensate the demand variation. The risk of the scenarios is also estimated to select the optimal generation scenario. The advantage of this method is that the optimum generator scheduling can be calculated in the present load dispatching system since the existing scheduling algorism can be easily adopted with a minimum modification.

基于动态转动光束的光镊力快速测量

An efficient and inexpensive method that uses a glass plate mounted onto a motorized rotating stage as a beam-steering device for the generation of dynamic optical traps is reported. Force analysis reveals that there are drag and trapping forces imposed on the bead in the opposite directions, respectively, in a viscous medium. The trapped bead will be rotated following the beam's motion before it reaches the critical escape velocity when the drag force is equal to the optical trapping force. The equilibrium condition facilitates the experimental measurement of the drag force with potential extensions to the determination of the viscosity of the medium or the refractive index of the bead. The proposed technique can easily be integrated into conventional optical microscopic systems with minimum modifications.

A Framework for Goodput Optimization in P2P Streaming over Wireless Ad-Hoc Networks

Since the Content Distribution Network (CDN) and IP multicast have heavy infrastructure requirements, their deployment is quite restricted. In contrast, peer-to-peer (P2P) streaming applications are independent on infrastructures and thus have been widely deployed. Emerging wireless ad-hoc networks are poised to enable a variety of streaming applications. However, many potential problems, that are trivial in wired networks, will emerge when deploying existing P2P streaming applications directly into wireless ad-hoc networks. In this paper, we propose a goodput optimization framework for P2P streaming over wireless ad-hoc networks. A two-level buffer architecture is proposed to reassign the naive streaming systems' data requests. The framework adopts a chunk size-varying transmission algorithm to obtain smooth playback experience and acceptable overhead and utilize limited bandwidth resources efficiently. The distinguishing features of our implementation are as follows: first, the framework works as a middleware and is independent on the streaming service properties; existing P2P streaming application can be deployed in wireless ad-hoc networks with minimum modifications and development cost; second, the proposed algorithm can reduce unnecessary communication overheads compared with traditional algorithms which gain high playback continuity with small chunk size; finally, our scheme can utilize low bandwidth transmission paths rather than discarding them, and thus improve overall performance of the wireless network. We also present a set of experiments to show the effectiveness of the proposed mechanism.

OPAL: A multiscale multicenter simulation package based on MPI‐2 protocol

AbstractBy using MPI‐2 standard, we designed and implemented a new multiscale simulation architecture OPAL. It requires minimum modification to existing simulation code as maintaining the execution efficiency. The new architecture is capable of dynamical region identification, dynamical process spawning, and is grid‐computing friendly. We demonstrated its usage and power with a simple test case: NaCl dissociation in water. The code shows excellent linear scaling capability, and no obvious degradation is observed. The communication time used by OPAL is negligible compared with its execution time, proving its high efficiency. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

Puddle Dynamics and Air-to-Fuel Ratio Compensation for Gasoline-Ethanol Blends in Flex-Fuel Engines

Ethanol is being increasingly used as an alternative fuel to petroleum-based gasoline and diesel derivatives. Currently available flexible fuel vehicles (FFVs) can operate on a blend of gasoline and ethanol in any concentration of up to 85% ethanol (93% in Brazil) with minimum hardware modifications. This flexibility is partly achieved through the closed-loop air-to-fuel ratio control which maintains automatically operation around the stoichiometric ratio. Precise transient air-to-fuel ratio (AFR) control depends however on a feedforward compensator that reduces the transient effects of fuel puddle dynamics. An accurate and tunable model of the fuel puddle dynamics for gasoline-ethanol blends is, thus, necessary for the purpose of AFR control. In this paper, we propose a physics-based fuel puddle model that may be used for control purposes in flex-fuel vehicles. In particular, the gasoline-ethanol blend is modeled using several chemical compounds and is parameterized by ethanol content. The model consists of a droplet evaporation model and a single-puddle vaporization model. The droplet evaporation model is simulated offline to generate port wall-impacting factors of injected fuel to be used in a single-puddle vaporization model. The single-puddle vaporization model is a cycle-based model that may be simulated online to characterize fuel puddle dynamics in port fuel injected engines. To verify the validity of the model, simulation results are compared with limited experimental data. A transient fuel compensator based on the proposed model is also formulated.

Behavioural Models for Group Communications

Group communication is becoming a more and more popular infrastructure for efficient distributed applications. It consists in representing locally a group of remote objects as a single object accessed in a single step; communications are then broadcasted to all members. This paper provides models for automatic verification of group-based applications, typically for detecting deadlocks or checking message ordering. We show how to encode group communication, together with different forms of synchronisation for group results. The proposed models are parametric such that, for example, different group sizes or group members could be experimented with the minimum modification of the original model.

자동추력 제어시스템 개발 및 검증

Modern version of advanced supersonic fighter have ATCS (Automatic Thrust Control System) to maximum flight safety, fuel efficiency and mission capability the integrated advanced autopilot system such as TFS (Terrain Following System), GCAS (Ground Collision Avoidance System) and AARS (Automatic Attitude Recovery System) and etc. This paper addresses the design and verification of ATCS based on advanced supersonic trainer in HILS (Hardware In the Loop Simulator) with minimum hardware modification to reduce of development cost and maintain of system reliability. The function of ATCS is consisted of target speed hold mode in UA (Up and Away) and angle of attack hold mode in PA (Power Approach). The real-time pilot evaluation reveals that pilot workload is minimized in cruise and approach flight stage by ATCS.

Biomass co-firing options on the emission reduction and electricity generation costs in coal-fired power plants

Co-firing offers a near-term solution for reducing CO 2 emissions from conventional fossil fuel power plants. Viable alternatives to long-term CO 2 reduction technologies such as CO 2 sequestration, oxy-firing and carbon loop combustion are being discussed, but all of them remain in the early to mid stages of development. Co-firing, on the other hand, is a well-proven technology and is in regular use though does not eliminate CO 2 emissions entirely. An incremental gain in CO 2 reduction can be achieved by immediate implementation of biomass co-firing in nearly all coal-fired power plants with minimum modifications and moderate investment, making co-firing a near-term solution for the greenhouse gas emission problem. If a majority of coal-fired boilers operating around the world adopt co-firing systems, the total reduction in CO 2 emissions would be substantial. It is the most efficient means of power generation from biomass, and it thus offers CO 2 avoidance cost lower than that for CO 2 sequestration from existing power plants. The present analysis examines several co-firing options including a novel option external (indirect) firing using combustion or gasification in an existing coal or oil fired plant. Capital and operating costs of such external units are calculated to determine the return on investment. Two of these indirect co-firing options are analyzed along with the option of direct co-firing of biomass in pulverizing mills to compare their operational merits and cost advantages with the gasification option.

Tube fitted bulk monolithic catalyst as novel structured reactor for gas–solid reactions

A novel fixed-bed reactor for gas–solid catalytic reactor using bulk monolithic catalyst (BMC), the so-called tube fitted bulk monolithic catalyst (TFBMC), instead of conventional packed bed reactor is presented. From the two types of monolithic catalyst, i.e. washcoated and the one made from bulk catalyst, the first one has been widely discussed in the literature. However, there is scarce report regarding the latter. In this research we have focused on introducing, preparation and application of TFBMC. Here, the two types of monolithic catalysts are compared. The advantages and disadvantages of the proposed concept as compared with packed bed reactor are discussed. Several parameters such as material, structure and preparation method of the catalysts are investigated. As a case study the mold ability and the performance of TFBMC in Fischer Tropsch synthesis (FTS) are explained. The results indicate that the TFBMC has superior advantages over the conventional fixed-bed reactors. Furthermore, the concept employed in fabrication of TFBMC may be easily applied with minimum modification to the conventional fixed-bed reactors which results in more productivity and better performance.

Portable system for temperature monitoring in all phases of wine production

This paper presents a low-cost and highly versatile temperature-monitoring system applicable to all phases of wine production, from grape cultivation through to delivery of bottled wine to the end customer. Monitoring is performed by a purpose-built electronic system comprising a digital memory that stores temperature data and a ZigBee communication system that transmits it to a Control Centre for processing and display. The system has been tested under laboratory conditions and in real-world operational applications. One of the system’s advantages is that it can be applied to every phase of wine production. Moreover, with minimum modification, other variables of interest (pH, humidity, etc.) could also be monitored and the system could be applied to other similar sectors, such as olive-oil production.

Process Evaluation of Oxy-fuel Combustion with Flue Gas Recycle in a Conventional Utility Boiler

In recent years, extensive studies were conducted to understand the potential implementation of oxy-fuel combustion with flue gas recycle in conventional boilers as an effort of mitigating CO2 emissions. The benefits of the technology include reduction of NOx and CO emissions by recycling more than 60% of the flue gas back into the boiler; generation of a flue gas stream with CO2 concentration higher than 90% on a dry basis, which can be easily recovered and stored; and utilization of the conventional boiler with minimum modifications. However, a practical implementation of the technology needs a thorough analysis of the mass and energy balance and their impacts on boiler thermal performance. This paper conducts a detailed process analysis on the oxy-fuel combustion with flue gas recycle in a conventional boiler. Key parameters such as the flue gas recycle ratio, boiler exit oxygen, and flue gas velocity and temperature distributions are investigated. Computational fluid dynamics (CFD) simulations are performed to help the understanding of the oxy-fuel combustion characteristics in a conventional boiler and in a single coal fired low NOx burner. The study shows that the ideal flue gas recycle ratio depends on boiler exit O2 and fuel properties and is generally around 0.7−0.75. Dry flue gas recycle helps to maintain the furnace temperature.

Minimal modification approach to red-shifted absorption and fluorescence in 1,8-naphthalimides

As a minimum modification approach toward longer wavelength chromophores, a series of (4-diethylamino-1,8-naphthaloyl)-aminopyridines were prepared with the pyridine nitrogen located at the ortho, meta, and para positions. Comparison between these isomeric neutral dyes and their corresponding pyridinium-1,3-propanesulfonate salts reveals a red-shift in both absorption (up to an emission of 1682 cm −1 in ethyl acetate) and emission. These observed shifts along with increased fluorescence quantum yield are attributed to polarization induced by the quaternary nitrogen of the pyridinium cation.

Improvement Potential and Equalization Example for Multidrop DRAM Memory Buses

For PC DRAM memory buses, the number of slots per channel have been decreased as signal frequencies increase. This limits the data capacity per channel. In this paper, we show that the slot reduction is not due to fundamental limits of the channel structure but due to signaling schemes. An equalization scheme is presented which enables higher bit-rates with minimum modification of bus structure and memory circuits. The circuitry added to the host side of the bus has reasonable complexity and features very low latency. Measurements of memory-to-host transmissions over a four-drop-bus at 2.6 Gb/s using a 0.13 mum CMOS test-circuit is presented.

Edge‐based finite element implementation of the residual‐based variational multiscale method

AbstractIn this work we extend our edge‐based stabilized finite element incompressible flow solver to turbulence modeling with the residual‐based variational multiscale (RB‐VMS) method. Using the advective‐form of the convection term of the Navier–Stokes equations, RB‐VMS is implemented as a straightforward extension of standard stabilized methods with a modified advective velocity. This requires minimum modification of the existing highly optimized code. Two test cases were solved to assess accuracy and performance of the present implementation. First, the laminar incompressible flow past a circular cylinder at Re = 100 and second, the fully turbulent incompressible flow in a lid‐driven cubic cavity at Re = 12000. Comparisons were made with standard stabilized finite element formulations, highly resolved numerical simulations and experimental data. Results have shown that the present implementation is able to achieve reasonable accuracy without performance degradation in different flow regimes. Copyright © 2008 John Wiley & Sons, Ltd.

Independent Tuning of Electronic Levels in Pentacene by Site‐Specific Substitution

Sensitive to position: Quantum-chemical calculations reveal site-specific substituent effects in pentacene via fluorination and methoxylation. The absolute position of HOMO and LUMO levels as well as the bandgap can be tuned independently of each other (see picture), thus paving a route to control electronic levels in (opto)electronic devices with minimum structural modification.

An Adaptive Finite Element Method for Minor Shape Modification in Optimization Algorithms

In this paper, we propose a method of adaptive finite element meshing, which is effective for minor shape modifications in optimization of electric machines. In the method, the mesh for the new shape in the optimization process is generated from the mesh of the previous shape with minimum modification. The locations of the nodes for the new shape are decided by solving the Laplace's equation, whose unknowns are displacements of the nodes. The adaptive finite element meshing is started from the modified mesh. The method can reduce the calculation time and improve the quality of the optimized results.

Feasibility Study of an Intercooled-Cycle Marine Gas Turbine

From the perspective of an overall entity we analyzed the performance obtainable from the adoption of an intercooled-cycle gas turbine under different typical cycle parameters of a gas turbine. On this basis, a study was conducted of the conversion of a high-power simple-cycle marine gas turbine (MGT-33) into a type of intercooled-cycle marine gas turbine. The precondition of the conversion is to keep the flow path and the majority of the structure of the original engine gas generator unchanged in order to inherit the reliability of the prototype machine. The results of the study indicate that after the adoption of an intercooled cycle under the precondition of performing minimum structure modifications and maintaining the compactness of the engine as a whole, there is still a significant enhancement of the gas turbine overall performance with its power output and efficiency being increased by about 34% and 4.1%, respectively, demonstrating the merits of the engineering conversion under discussion.

Process Intensification for the Retrofit of a Multicomponent Distillation PlantAn Industrial Case Study

Process intensification is currently considered as the main trend to improve process performance, and one of the major approaches to this regard is to reduce the number of pieces of equipment in the plant. For distillation systems, thermal coupling technique provides such an approach to retrofit the traditional simple column configurations through the elimination of the condenser and/or the reboiler. In this work, starting from the existing plant with the simple columns, two types of retrofit alternatives are proposed. The first includes the possible alternatives by eliminating all the condensers and reboilers involving the submixtures. The second includes all the possible alternatives when only some of the condensers and/or reboilers are eliminated at one time. The latter solution represents less modification to the existing plant. In addition, in order to investigate the capital investment for the modified plant, all the obtained alternatives through the recombination of the column sections have been compared. All the configurations were compared with respect to energy saving and the possibilities to reuse the plant equipment. The optimal solution was found to be the alternative that has the minimum modification to the existing plant. At the same time, it achieves a 23% savings on energy consumption and allows a maximum reuse of the pieces of the existing equipment.

Poster 146: Development of Regenerative Therapy for the Tooth Using Cell Lines Derived From Tooth Germs: Transplantation of Ameloblast-Lineage Cells Into Subcutaneous Tissue of Nude Mouse

Poster 146: Development of Regenerative Therapy for the Tooth Using Cell Lines Derived From Tooth Germs: Transplantation of Ameloblast-Lineage Cells Into Subcutaneous Tissue of Nude Mouse