Tobin's imperfect asset substitution in optimizing general equilibrium

In this paper, we present a dynamic optimizing model that allows explicitly for imperfect substitutability between different financial assets. This is specified in a manner which captures Tobin's (1969) view that an expansion of one asset's supply affects both the yield on that asset and the spread or "risk premium" between returns on that asset and alternative assets. Our estimates of this model on U.S. data confirm that some of the observed deviations of long-term rates from the expectations theory of the term structure can be traced to movements in the relative stocks of financial assets. The richer aggregate demand and asset specifications imply that there exists an additional channel of monetary policy. Our results suggest that central bank operations exercise a modest influence on the relative prices of alternative financial securities, and so exert an extra effect on long-term yields and aggregate demand separate from their effect on the expected path of short-term rates.Monetary policy ; Macroeconomics

Sticky-price models and the natural rate hypothesis

A major criticism of standard specifications of price adjustment in models for monetary policy analysis is that they violate the natural rate hypothesis by allowing output to differ from potential in steady state. In this paper we estimate a dynamic optimizing business cycle model whose price-setting behavior satisfies the natural rate hypothesis. The price-adjustment specifications we consider are the sticky-information specification of Mankiw and Reis (2002) and the indexed contracts of Christiano, Eichenbaum, and Evans (2005). Our empirical estimates of the real side of the economy are similar whichever price adjustment specification is chosen. Consequently, the alternative model specifications deliver similar estimates of the U.S. output gap series, but the empirical behavior of the gap series differs substantially from standard gap estimates.Monetary policy ; Prices

Detection of inter-turn faults in multi-phase ferrite-PM assisted synchronous reluctance machine

Inter-turn winding faults in five-phase ferrite-permanent magnet-assisted synchronous reluctance motors (fPMa-SynRMs) can lead to catastrophic consequences if not detected in a timely manner, since they can quickly progress into more severe short-circuit faults, such as coil-to-coil, phase-to-ground or phase-to-phase faults. This paper analyzes the feasibility of detecting such harmful faults in their early stage, with only one short-circuited turn, since there is a lack of works related to this topic in multi-phase fPMa-SynRMs. Two methods are tested for this purpose, the analysis of the spectral content of the zero-sequence voltage component (ZSVC) and the analysis of the stator current spectra, also known as motor current signature analysis (MCSA), which is a well-known fault diagnosis method. This paper compares the performance and sensitivity of both methods under different operating conditions. It is proven that inter-turn faults can be detected in the early stage, with the ZSVC providing more sensitivity than the MCSA method. It is also proven that the working conditions have little effect on the sensitivity of both methods. To conclude, this paper proposes two inter-turn fault indicators and the threshold values to detect such faults in the early stage, which are calculated from the spectral information of the ZSVC and the line currentsPeer ReviewedPostprint (published version

Evaluación de los procesos de certificación de las normas Orgánica, Rainforest Alliance y de protección a aves en el entorno cafetero “Bird Friendly” de la Hacienda Majavita, del Socorro, departamento de Santander.

Actualmente la Hacienda Majavita se encuentra certificada como finca productora de café Organico, sostenible ambientalmente (Rainforest Alliance) y de proteccion de aves en el entorno cafetero (Bird Friendrly); el avance e incorporación de nuevos requisitos y criterios por parte de las normas, crea la necesidad de actualización de los procesos para dar cumplimiento y mantener la certificación. El objetivo del presente trabajo está encaminado a la evaluación del sistema de certificación y el cumplimiento de criterios para adelantar procesos de mejora continua. El trabajo se desarrolla mediante el diagnostico de los componentes ambientales de la zona y la recolección de información de los ecosistemas, la fauna y la flora de la finca, tambien de efectua la evaluación de los criterios relacionados con el cumplimiento de los requisitos de las normas y los procesos ejecutados de acuerdo a las herramientas suministradas por Rainforest Alliance, adicionalmente se implementa un Sistema de Información Geografica para abarcar los criterios con necesidades de información espacial de la finca, los ecosistemas, la vegetación, el sistema agroforestal, entre otros, y por ultimo se diciona como propuesta un plan de manejo integrado de plagas (MIP) y un plan de acción. Como resultado, se evaluaron y efectuaron procesos para el cumplimiento de los requisitos de las normas, se obtuvo información detallada de la finca, el sistema agroforestal y estado actual de los ecosistemas, tambien se abordaron medidas para los componentes de las normas y se estructuró el acopio de información.Universidad Libre Seccional Socorro -- Facultad de Ingenierías y Ciencias Agropecuarias -- Ingeniería AmbientalCurrently, the Majavita Hacienda is certified as a farm that produces organic coffee, environmentally sustainable (Rainforest Alliance) and bird protection in the coffee environment (Bird Friendly); The progress and incorporation of new requirements and criteria by the standards creates the need to update the processes to comply with and maintain the certification. The objective of this work is aimed at the evaluation of the certification system and the fulfillment of criteria to advance processes of continuous improvement. The work is carried out through the diagnosis of the environmental components of the area and the collection of information on the ecosystems, fauna and flora of the farm, as well as the evaluation of the criteria related to compliance with the requirements of the regulations. and the processes executed according to the tools provided by the Rainforest Alliance, additionally a Geographic Information System is implemented to cover the criteria with spatial information needs of the farm, the ecosystems, the vegetation, the agroforestry system, among others, and by Lastly, an integrated pest management plan (IPM) and an action plan are listed as a proposal. As a result, processes were evaluated and carried out to comply with the requirements of the standards, detailed information on the farm, the agroforestry system and the current state of the ecosystems was obtained, measures for the components of the standards were also addressed and the process was structured. information gathering

Effects of extraction pH of chia protein isolates on functional properties

The aim of this work was to study the effect of the extraction pH on the functional properties of chia protein isolates (CPI). Samples were named as CPI10 or CPI12, according to their extraction pH, 10 or 12, respectively. Functional properties were significantly modified by the extraction pH. Color properties revealed that CPI12 presented a lower L* (47.8 ± 0.9 for CPI10 and 30 ± 1 for CPI12). Besides, a higher b* value was obtained for CPI12 (7.0 ± 0.3 for CPI12 and 5.6 ± 0.7 for CPI10), as a result of a higher ash content. CPI12 showed a higher WAC probably due to a higher exposure of polar amino acids (4.4 ± 0.1 g/g and 6.0 ± 0.2 g/g), whereas CPI10 showed a higher ability to bind oil (7.1 ± 0.2 g/g and 6.1 ± 0.2 g/g for CPI10 and CPI12, respectively). CPI10 proved more appropriate as an emulsion stabilizer than CPI12, which could be due to its higher surface hydrophobicity, protein solubility and negative net charge. The d4,3 (μm) was 29.5 ± 0.4 and 20.4 ± 0.3 in emulsions stabilized with CPI12 and CPI10, respectively. Although both isolates underwent heat gelation, they exhibited a weak gel behavior. Overall, CPI10 may be more suitable for the food industry as a meat replacer or extender.Fil: López, Débora Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; ArgentinaFil: Ingrassia, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; ArgentinaFil: Busti, Pablo Andres. Universidad Nacional de Rosario; ArgentinaFil: Wagner, Jorge Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Spelzini, Darío. Universidad Nacional de Rosario; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Boeris, Valeria. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario; Argentin

Liquid bridge breakages aboard SPACELAB-D1

The study of the stability of long liquid columns under microgravity was the purpose of one of the experiments carried out aboard Spacelab-Dl. In this paper a preliminary analysis of this experiment, mainly concerning the different liquid column breakages, is presented. As shown in the paper, the behaviour, both static and dynamic, of long liquid bridges can be accurately predicted by using available theoretical models

AC transmission network expansion planning considering circuits repowering and location of capacitors

RESUMEN: En este artículo se aborda el problema de Planeamiento de la Expansión de la Red de Transmisión (PERT). El PERT consiste en determinar el conjunto de nuevos circuitos necesarios en un sistema de potencia, para atender una demanda futura. En su versión clásica, el PERT considera como candidatos de solución únicamente la adición de nuevas líneas y transformadores. La principal contribución de este artículo consiste en la inclusión de candidatos de solución no convencionales en el PERT. Dichos candidatos de solución son la repotenciación de circuitos existentes y la ubicación de bancos de capacitores. Para tener en cuenta estos últimos, se considera un modelo AC de la red de transmisión. La solución al modelo propuesto es llevada a cabo mediante un Algoritmo Genético Híbrido. Los resultados obtenidos son contrastados y validados con publicaciones previas de la literatura técnica. Los sistemas de prueba utilizados son el sistema Garver y el sistema IEEE de 24 barras. Los resultados obtenidos en ambos sistemas muestran que la inclusión de los candidatos no convencionales propuestos en este artículo permite disminuir los costos de la expansión de la red. Este hecho puede servir como indicador para que el planeador del sistema contemple nuevas posibilidades en los estudios de expansión.ABSTRACT: This paper deals with the Transmission Network Expansion Planning (TNEP) problem. The TNEP consists of finding a set of new circuits on a power system, which is needed to attend a future demand. In its classical version, the TNEP only considers as solution candidates the addition of new lines and transformers. The main contribution of this paper consists in the inclusion of non-conventional solution candidates, namely the repowering of existing circuits and the location of capacitor banks. To take into account these last ones an AC model of the transmission network is considered. The solution of the proposed model is carried out using a Hybrid Genetic Algorithm. Results are compared and validated with previous works in the technical literature. The test systems used are the Garver system and IEEE 24 bus system. The results obtained in both systems showed that the inclusion of the non-conventional candidates, proposed in this paper, allows to reduce the cost of network expansion. This fact may be useful as an indicator for the system planner to consider new possibilities in the expansion studies