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High-purity vanadium single crystals, having resistivity ratios in the range 1 100 – 1 800, were compression tested at 295 K, 173 K and 77 K. Samples having orientations near the [011] - [ 1 11] tie line slip on expected planes. Samples having a central, or near [001] orientation slip on the anomalous (0 1 1) plane at lower temperatures.

This paper traces the history of early developments in the field of automatic speed and tie-line control and brings the picture up to date with a discussion of those problems which are still unsolved and which will require more mutual understanding and co-operation between the various engineers involved.

The load-frequency control models of a two-area interconnected power system with stiff and elastic tie-line are investigated with respect to modeling errors. Only multiplicative type modeling errors are considered for robustness analysis. It is shown that the elastic tie-line model presents a higher degree of robustness.

The two phase systems that result when aqueous solutions of dextran and poly(ethylene glycol) (PEG) are mixed above a critical concentration of a few percent provide a useful medium for the separation of biological cell subpopulations via partition between the top, PEG-rich phase and the liquid-liquid phase boundary. Interfacial tensions of such systems have been measured by the rotating drop technique and found to range between 10−1 and 102 μN m−1 . The tension was found to depend on the length of the tie line describing the system on a phase diagram, via a power law relationship which differed depending on the concentration of Na phosphate buffer present. The electrokinetic properties of drops of one phase suspended in the other were studied for a variety of systems. It was found that the droplet electrophoretic mobility increased monotonically with phosphate concentration and drop diameter but exhibited the opposite sign from that anticipated from phosphate partition measurements. It was possible to take advantage of these electrokinetic properties and dramatically enhance the speed of phase separation through application of relatively small electric fields.

This paper presents a digital simulation study of the use of a static thyristor-controlled phase shifter as an effective power controller to enhance system stability and to damp the line electromechanical oscillations, hence to improve AC tie line capacity. A dynamic model of the static phase shifter is incorporated in the integrated power system dynamics; the unified state space form is used to investigate digital and analog control laws to transform static phase shifters into viable tools in enhancing interconnected power system steady state stability.

Silicon oxynitride thin films made by RF reactive sputtering can be made with varying composition along the silicon dioxide - silicon nitride tie line by control of the sputtering gases. Compositional determination was made by the Rutherford backscattering technique. A simple model relating film composition to the composition of the reactive gases is proposed which fits the experimental results.

This paper proposes that the line flow fluctuation can be used as a new security factor to assess the total system damping of the slow natural mode. The line flow fluctuation is evaluated by partitioning its power spectrum into two major oscillatory modes. The 24 data points observed at the tie line in the central-east area of Japan, are used to extract the features of the fluctuations. A significant result is a droop characteristic of the fluctuation spectrum with respect to the system demand. The system status can be separated into the SECURE and ALERT state by using the above characteristic. The statistical investigation has been done for identifying the local damping effect.

The author's hierarchical state estimation concept for large-scale power systems is extended. Three fast and flexible methods arising from this concept are proposed to handle power pools and regional power systems. These methods are based on a properly organised cooperation among pool member utilities, aimed at providing reliable and accurate estimates of tie line flows and boundary bus injections. Pool-wide state estimates are obtained using elementary, scalar linear equations which are used to coordinate utility state estimates. Some application aspects relating to the methods are also briefly outlined.

For more than two decades, the problem of load frequency control (LFC) using conventional or advanced-control theory has been the subject of numerous studies. The conventional LFC approach often employs what is called the tie-line bias concept to design a system controller that has a proportional-plus-integral (PI) action. This type of control is used extensively in practice in preference to all the techniques that have been proposed recently, employing modern control theory. The reason for that is that most recent techniques have developed linear feedback controls that are functions of all the system state variables as well as the system disturbances (Refs. 5.1, 5.2). Therefore, it was necessary to design an observer to realize these kind of controls (Ref. 5.3). Once an observer is introduced into the system, the cost is increased, and the control is no longer optimal (Ref. 5.4). Another important reason is that a control that depends upon all the system states needs some of these state variables to be telemetered, since the areas of interconnected power systems (IPS) are spread over large geographical territories. This is why, in practice, control engineers prefer to use the conventional control to the advanced one, in spite of the contention that the latter improves the system transient performance.

After the present solid slugs are replaced with the new I&E elements` in the 105-B reactor, the friction loss for the reactor cooling water will be decreased with a resulting opportunity for increase in flow through the reactor. The amount that this flow could be increased is limited by the capacity of the B water plant as well as the reactor itself. It is possible that there will be a shortage of filtered water at 183-B during the critical periods of each year. To overcome this possible shortage of water it has been proposed to construct a thirty inch tie line from the 183-C reservoir to the 183-B clear-well to supply filtered water to 183-B by gravity flow from 183-C. This report presents justification and the scope of this project.

This work aimed to establish the relationship between the compositions and pH of ATPS PEG 6000/CaCl2 and the proteins partition from maize malt and also to simplify the process optimization in ATPS for a statistical model, established by response surface methodology (RSM). Results showed that these were no influence of pH on the phase diagrams and on the composition of tie line length of PEG 6000/CaCl2 ATPS. SRM analyses showed that elevated pH and larger tie line length were the best conditions for recovering of maize malt proteins. The maximum partition coefficient by PEG 6000/CaCl2 ATPS was about 4.2 and was achieved in ATPS in a single purification step. The theoretical maximum partition coefficient was between 4.1-4.3. The process was very suitable for continuous aqueous two-phase purification due to the stability of proteins (e.g. and -amylases) and could increase their content into middle.Este trabalho objetivou encontrar uma relação entre a composição e o pH do sistema bifásico aquoso (SBA) PEG 6000/CaCl2 e a partição de proteínas do malte de milho, e assim simplificando a otimização do processo por um modelo estatístico, estabelecido por metodologia de superfície de resposta (RSM). Os resultados mostraram que não houve influência do pH sobre os diagramas de fases e sobre a composição das linhas de amarração do SBA PEG/CaCl2. As analises RSM mostraram que em pH elevado e nas maiores linha de amarração encontra-se a melhor condição para a recuperação das proteínas do malte de milho. O coeficiente de partição máximo foi cerca de 4,2 para uma única etapa de purificação no SBA 6000/CaCl2. O coeficiente de partição máximo encontrado teoricamente esteve entre 4,1-4,3. O processo é adequado para a purificação contínua via sistemas bifásicos aquosos, já que as proteínas do malte (ex: e -amilases) são estáveis e podendo elevar sua concentração no meio.

Liquid-Liquid equilibrium data were obtained for the polyethylene glycol2000(PEG2000)-sodium citrate-water system at 298.15, 308.15 and 318.15 K. The effect of temperature on binodal and tie line data was studied and published in a previous article (Murugesan and Perumalsamy, 2005). The interaction parameters of ASOG and UNIFAC models were estimated using the LLE data of PEG2000-sodium citrate-water system and are used to predict the LLE data for PEG6000-sodium citrate-water system at 298.15, 308.15 and 318.15 K (literature data). The predicted LLE data by both ASOG and UNIFAC models showed good agreement with the experimental and literature data.

The chemical compatibility of silver electrodes and low-firing ceramics has been considered, in terms of the existence of a tie line between silver (and/or Ag2O) and the binary oxide compound in the corresponding ternary phase diagram. The probability of the existence of the tie line is related to the conditions in the subordinated silver-based isothermal binary systems. Greater probabilities have been calculated for the systems with fewer silver-based binary compounds. Based on the concepts that have been developed, several silver-based isothermal binary systems have been investigated to identify the oxides suitable for the development of low-temperature cofired ceramics. The developed concept has been tested by investigating the phase relations in the Bi2O3–Nb2O5 and Bi2O3–V2O5 ternary systems with silver. X-ray and microstructural investigations of bismuth niobates and bismuth vanadates reveal that, as a result of the inertness of Bi2O3 and the reactivity of Nb2O5 and V2O5 toward silver, compounds that are rich in niobium or vanadium react with silver to form ternary Nb/V-Bi-Ag oxide compounds, whereas for compounds that are rich in bismuth, tie lines to silver and Ag2O do exist.

In the past decade, enhancing the reliability of distribution networks by means of optimal switch placement has attracted much attention. In the case of failures in a distribution feeder, such disconnect switches will isolate the faulted section, and the customers downstream of the faulted point can be supplied by neighboring feeders through tie lines. Nevertheless, such reserve branches not only might experience failures themselves but also may not even exist prior to the switch placement. Accordingly, this paper presents a mathematical-programming-based model for the concurrent placement of disconnect switches and tie lines in the distribution networks to enhance the service reliability, considering both practical benefits and drawbacks of such reserve branches. In the proposed model, installation of remote-controlled and manual switches at various locations of distribution feeders together with potential tie lines are considered. Also, practical operational constraints regarding the utilization of tie lines, and the impact of failures in such reserve branches on the reliability indices are meticulously modeled in the proposed formulation. Unreliability cost is estimated based on a reward-penalty scheme and the revenue lost due to the not supplied demand during the network contingencies. As an instance of mixed-integer linear programming, the proposed optimization model can be efficiently solved to the global optimality using commercially available software. Aiming at investigating the applicability of the proposed model, it is implemented on a test network, and the results are thoroughly analyzed through various case studies.

We describe an Adaptive Compositional Space Parametrization (ACSP) method for compositional flow simulation. The method is based on casting the nonlinear governing equations, including those that describe the thermodynamic phase equilibrium, in terms of the tie-simplex (tie-lines for two-phase flow) space. The tie-simplex compositional space, which is a function of composition, pressure, and temperature, is then discretized using a limited number of tie-simplexes. The coefficients in the governing system of equations, including the composition, density, and mobility of the phases, are computed using multilinear interpolation in the discretized space. ACSP is different from the CSAT (Compositional Space Adaptive Tabulation) approach, which we have evolved over the last few years. In CSAT, the tie-line (tie-simplex) information, which is stored and updated adaptively, is used to accelerate the equation-of-state (EOS) computations in standard (e.g., natural variables) compositional reservoir simulators. This is why CSAT was used primarily to essentially replace the phase-stability test in the natural-variables formulation, but not the flash procedure. In ACSP, on the other hand, the full mathematical statement is cast in tie-simplex space and consistent discretization is applied directly. The ACSP framework is supplemented with a new tie-line based flash procedure that avoids the use of the Rachford-Rice equation. Thus, ACSP replaces all the standard EOS computations (phase-stability and flash). A grid refinement study of the ACSP method shows that the discrete formulation is convergent; more importantly, even for highly nonlinear near-miscible displacements, the number of tie-simplex needed is small.

A salient pole synchronous machine with modern governors connected through a short tie line to an infinite oscillating bus has heen considered. Using harmonic balance principle effect of change in system parameters on sustained machine variables have been investigated.

The American Louisiana Pipe Line Co. as part of its overall 1,200‐mile project began construction of the 22‐in. tie line extending from Defiance, Ohio, to Bridgman, Michigan, thus effecting a tie‐in with its affiliate company, Michigan Wisconsin Pipe Line Co. The construction of this line was begun early in September 1956 and was completed by November 15, 1956. This segment of the 22‐in. line was 122 miles in length and represented the first large‐diameter line to be completely protected by the use of plastic tape, thus setting a precedent in the field of protective coatings for large‐diameter pipe.

The paper describes operating experience with tie-line load regulators on the tie connecting the Colfax Power Station of the Duquesne Light Co. and the Springdale Station of the West Penn Power Co. A description is given of the equipment used and also of supplementary equipment, such as program loading equipment installed at Colfax to maintain the most economic division of load between the various generating units. A new hydraulic speed changing device intended to reduce wear on the governor parts to a minimum is also described. Tests made jointly by the Duquesne Light and West Penn Power Companies to determine the effect of operating frequency and tie-line regulators simultaneously are discussed and the curves giving the results are shown.

The formation of mixed phases in the system MgF2+ Nb2O5 has been examined, on the grounds that similarity in ionic radii between Mg and Ti, and between F and O, should lead to the analogues of the known titanium–niobium block structure oxides. Electron diffraction and direct electron microscope lattice imaging methods show that, in addition to the compound already described as MgNb14O35F2, with the (5 × 3)∞ structure, phases iso-structural with H-Nb2O5, N-Nb2O5, TiNb24O62, and Ti2Nb10O29 are formed. By compensatory substitution, each of these structures represents a solid solution series and mixtures with compositions on the MgF2–Nb2O5 tie line yield multiphase products. Regular intergrowth structures may be formed between the basic structural types.

The tie line is determined most simply by forming a two=phase mixture, weighing separately the two phases, and finding the ratio of the phase masses.

Over the past decade and a half there have been proposed three schemes of control for electricity supply systems interconnected through tie lines. In chronological order they are the speed-governed system with frequency biasing, the time-governed system and the load-phase energy control. The paper describes computer studies which compare the three systems using a performance index of the integral square error. Certain conclusions are drawn by applying this criterion both to the frequency error of the isolated system and to the tie power-flow error of the interconnected system.

This experiment involves tie line correlation and Plait Point determination for an acetic acid-benzene-water system.

THE Southern California Edison Company, with approximately 2,187 megawatts (mw) of effective operating capacity, 52 per cent of which is steam driven, is a participant in the 8,800-mw Pacific Southwest power area. In this operating area, the load changes on the systems and interchange of power across the interconnecting ties will on occasion impose rate-of-generation changes of 25 to 30 mw per minute, for periods of relatively short duration. The control of the tie line load and combined system frequency is maintained by automatic load- and frequency-control equipment, with one system regulating frequency, and the remaining systems controlling their ties with the regulating system.

THIS ARTICLE extends a previous study1 to include hydroelectric power generating areas. As before, the object is to determine theoretically the best values of controller gains; that is, to find those controller settings that will result in best over-all system performance.

IF ALL TIE LINES were of ample capacity and stations under automatic control were well distributed geographically, there would be no need for tie line control except where required by contract interchange schedules. With the large scale advent of system interconnections and the necessity for more efficient operation, the tendency is to use frequency control biased by tie line load rather than frequency control only.

The ternary phase diagrams Ge‐Si‐Sn and Ge‐Si‐Pb have been calculated based on the quasi‐chemical equilibrium treatment of the lattice model for both the liquid and solid solutions. The calculation, using temperature independent interaction parameters obtained by fitting the calculated binary liquidus curves to experimental data, agrees to within experimental error with liquidus and tie line data obtained from the steady‐state epitaxial growth of Si‐Ge alloys from Sn and Pb solutions.

THE PROBLEM of matching the generation to the load is basic with the electrical industry. Since the very earliest days of a-c systems, the maintenance of a frequency equal to the nominal figure at which the system operates has provided the simplest indication of this balance. Until the late 1920's very little consideration was given to anything more than approximate accuracy of frequency, with the result that deviations from normal of as much as 1/2 cycle were not at all uncommon. Integrated time was of no consequence.