188 research outputs found
MAGAZINE SALES PROMOTION: A DYNAMIC RESPONSE ANALYSIS
This paper studies the impact and effectiveness of a type of non-price promotion often used in the European periodical magazines industry to stimulate sales, in which a value pack is sold containing the magazine issue plus another product. Magazines are sold simultaneously with and without promotion at different prices, and promotions are serialized by fractioning the additional product across different issues of the magazine. We find that promoted magazines contemporarily cannibalize non-promoted sales; but this loss is compensated by a medium term increase of non-promoted sales. These results show that this sales promotion strategy is an effective way to diminish the decline rate of periodical sales.
OPTIMAL DURATION OF MAGAZINE PROMOTIONS
The planning of promotions and other marketing events frequently requires manufacturers to make decisions about the optimal duration of these activities. Yet manufacturers often lack the support tools for decision making. We assume that customer decisions at the aggregated level follow a state-dependent Markov process. On the basis of the expected economic return associated with dynamic response to stimuli, we determine the ideal length of marketing events using dynamic programming optimization and apply the model to a complex promotion event. Results suggest that this methodology could help managers in the publishing industry to plan the optimal duration of promotion events.
DO BUSINESS DENSITY AND VARIETY DETERMINE RETAIL PERFORMANCE?
Outlet location plays a crucial role in retail strategy. In this paper we study the relationship between spatial density (concentration) of retailers in the trade area and their economic performance. This analysis will help managers figure out the economic potential of starting a retail business in a given area, reducing business start-up risks. We find that retail businesses located in high and low retail density zones enjoy higher performance levels, consistent with competitive advantage arising from agglomeration economies and local market power respectively. We also find that retail businesses located in intermediate density areas use a differentiation strategy based on business variety (diversification across stores). Outlets located in areas with the highest variety enjoy performance levels similar to those achieved in the agglomeration and low density areas. The results suggest that retail companies should jointly consider variety and density to determine location.
Evaluation of a Local Fault Detection Algorithm for HVDC Systems
A great increase in the amount of energy generated from clean and renewable sources integrated in the electric power system is expected worldwide in the coming years. High Voltage Direct Current (HVDC) systems are seen as a promising alternative to the traditional Alternating Current (AC) systems for the expansion of the electric power system. However, to achieve this vision, there are some remaining challenges regarding HVDC systems which need to be solved. One of the main challenges is related to fault detection and location in HVDC grids. This paper reviews the main protection algorithms available and presents the evaluation of a local fault detection algorithm for DC faults in a multi-terminal Voltage Source Conversion (VSC) based HVDC grid. The paper analyses the influence of the DC voltage sampling frequency and the cable length in the performance of the algorithm. © 2019, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ).The authors thank the support from the Spanish Ministry of Economy, Industry and Competitiveness (project ENE2016-79145-R AEI/FEDER, UE) and GISEL research group IT1083-16), as well as from the University of the Basque Country UPV/EHU (research group funding PPG17/23)
Crystallization kinetics as a sensitive tool to detect degradation in poly(lactide)/poly(ε-caprolactone)/ PCL-co-PC copolymers blends
Poly(lactide)/poly(ε-caprolactone) blends (PLA/PCL) with composition 80/20 (w/w%) are immiscible but biodegradable and therefore often studied in the literature. We have prepared 80/20 PLA/PCL blends with and without poly(ε-caprolactone)-co-poly(carbonate) copolymers (block and random). The blends were prepared both by melt extrusion and by solution blending. The concentration of PCL-co-PC copolymers added to the blends was 2 wt%. Compression molded sheets and solvent cast films were evaluated by GPC (Gel Permeation Chromatography), TGA (Thermogravimetric Analysis), SEM (Scanning Electron Microscopy), PLOM (Polarized Light Optical Microscopy) and DSC (Differential Scanning Calorimetry). Copolymer addition causes a reduction of molecular weight in melt mixed blends. In particular, the random copolymer (PCL-ran-PC) causes the highest molecular weight reduction, since it has lower thermal stability, as shown by TGA. PLOM experiments show that these degraded PLA chains in melt-mixed blends can nucleate and grow faster than similar but undegraded PLA chains in solution-mixed blends. As a result, the PLA phase within melt mixed blends containing PCL-co-PC copolymers shows a higher tendency to crystallize during both isothermal and non-isothermal DSC experiments. Upon molecular weight reduction in melt mixed blends containing copolymers, PLA chains have a higher mobility resulting in faster diffusion towards the growing crystal front. Our results show crystallization kinetic measurements, performed by PLOM or DSC, are useful tools to qualitatively detect molecular weight changes produced by degradation of PLA chains, when the molecular weight reduction is not large enough to decrease Tm values
RazĂłn de sexos y morfometrĂa de Calidris minutilla (Aves, Scolopacidae) en Cuba: un análisis a partir de especĂmenes en colecciones cientĂficas
Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfomĂ©tricas tanto en los lugares de crĂa como en los de invernada. Se documentan la razĂłn de sexos (N = 99) y medidas morfomĂ©tricas (N = 49) del zarapiquito en Cuba a partir de especĂmenes conservados en colecciones cientĂficas. Además, se evalĂşan posibles variaciones en la longitud del pico teniendo en cuenta la ubicaciĂłn longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporciĂłn de hembras fue del 0,47 y las medidas morfomĂ©tricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles Ăşnicamente al sexo y no a las caracterĂsticas del lugar de captura.Calidris minutilla (Least Sandpiper) populations exhibit morphometric variation across breeding and wintering sites. We documented sex ratio (N = 99) and morphological measurements (N = 49) of Least Sandpiper inhabiting Cuba using specimens in museum collections. We also assessed bill length variation in relation to the longitude (degrees) and type of coastal zone where sampling was conducted. Proportion of female was 0.47 and morphometric measurements were within the range described for the species. Differences in bill length were explained by sex but not by sampling site characteristics.Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfomĂ©tricas tanto en los lugares de crĂa como en los de invernada. Se documentan la razĂłn de sexos (N = 99) y medidas morfomĂ©tricas (N = 49) del zarapiquito en Cuba a partir de especĂmenes conservados en colecciones cientĂficas. Además, se evalĂşan posibles variaciones en la longitud del pico teniendo en cuenta la ubicaciĂłn longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporciĂłn de hembras fue del 0,47 y las medidas morfomĂ©tricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles Ăşnicamente al sexo y no a las caracterĂsticas del lugar de captura
Análisis epistemolĂłgico en revistas del campo de la ArchivĂstica: Archivaria, Archival Science, Tábula, The American Archivist, Archives and Records, y Acervo durante el perĂodo 2009-2014
The main intentions of an analysis of the archival reality are presented in the scenario of the periodic publications, due to the absence of studies that manage these topics in an integrative way. This observation unit is selected because it is the place where the archival analysis is made. Some aspects of the archival science embraced, such as its theory development that is indissolubly bound with its practice. However, to determinate which topics about this science’s epistemology are the most treated; it is necessary to appreciate the behavior of the scientific production in the main dialogue platforms and written exchange, through the metric techniques and the back-up of metric indicators that allow evaluating with more easiness this topical statements. It is considered that this work can be a form of revealing relative aspects of the intellectual activity on the archival science epistemology.Se presentan las principales intenciones de análisis de la realidad archivĂstica reflejada en el escenario de las publicaciones periĂłdicas, debido a la ausencia de estudios que manejen estos temas de forma integradora. Se selecciona esta unidad de observaciĂłn, puesto que en ellas tienen lugar los debates archivĂsticos que se pretenden analizar. Sobre la ciencia archivĂstica se abarcan aspectos tales como el desarrollo de su teorĂa, que se encuentra indisolublemente ligada a la práctica. No obstante, para determinar quĂ© temáticas son tratadas con mayor auge sobre la epistemologĂa de esta disciplina, es necesario apreciar el comportamiento de la producciĂłn cientĂfica en las principales plataformas de diálogo e intercambio escrito, a travĂ©s de las tĂ©cnicas mĂ©tricas y el respaldo de indicadores que permitan evaluar con mayor facilidad dichos tĂłpicos. Se considera que este trabajo puede resultar una forma de revelar aspectos relativos a la actividad intelectual sobre la epistemologĂa archivĂstica
Análisis epistemolĂłgico en revistas del campo de la ArchivĂstica: Archivaria, Archival Science, Tábula, The American Archivist, Archives and Records, y Acervo durante el perĂodo 2009-2014
The main intentions of an analysis of the archival reality are
presented in the scenario of the periodic publications, due to the absence
of studies that manage these topics in an integrative way. This observation
unit is selected because it is the place where the archival analysis is
made. Some aspects of the archival science embraced, such as its theory
development that is indissolubly bound with its practice. However, to
determinate which topics about this science’s epistemology are the most
treated; it is necessary to appreciate the behavior of the scientifi c production
in the main dialogue platforms and written exchange, through the
metric techniques and the back-up of metric indicators that allow evaluating
with more easiness this topical statements. It is considered that this
work can be a form of revealing relative aspects of the intellectual activity
on the archival science epistemology
Polyurethane/acrylic hybrid dispersions containing phosphorus reactive flame retardants as transparent coatings for wood
Phosphorus modified polyurethane/acrylic hybrid dispersions were prepared for flame retardant transparent wood coatings. The polymerisation was carried out in three steps. In the first one, the polyurethane was synthesised using an acrylic monomer as solvent. The second step involved water addition that promoted the phase inversion and lastly, acrylic part was polymerised. The phosphorous compounds were covalently linked to polyurethane using a phosphorylated polyol and to the acrylic phase using an acrylic phosphate. Polymerisation was monitored by FTIR and NMR and the molar mass of the hybrids was measured by AF4 and SEC. The effects of the phosphorus in fire-retardant properties were analysed by thermogravimetry and pyrolysis combustion flow calorimetry. The introduction of phosphorus did not produce significant changes in the polymerisation process but promoted the cross-linking of the coatings. The coated wood samples maintained the transparency and good properties with the introduction of phosphorus and presented a slight reduction in the Peak Heat Release Rate measured by cone calorimeter. The action of phosphorus as a fire retardant was effective as it gave rise to significant reduction of the CO and CO2 peaks.The funding received from University of the Basque Country (GIU19/077, predoctoral grant of M. Puyadena and postdoctoral grant of M. Cobos) and the Basque Government (IT1313-19, PIBA20/16) is grate-fully acknowledged. Technical and human support provided by SGIker is also sincerely acknowledged (UPV/EHU/ ERDF, EU
Design and integration of WAAM technology and in situ monitoring system in a gantry machine
Wire arc additive manufacturing, WAAM, is a popular wire-feed additive manufacturing technology that creates components through the deposition of material layer-by-layer. WAAM has become a promising alternative to conventional machining due to its high deposition rate, environmental friendliness and cost-competitiveness. In this research work, an adaptation of a gantry machine with in-situ monitoring and a control system has been carried out, in order to expose the ability of the WAAM technology to fabricate complex-shaped parts. The retrofitting of the machine has been done in several layers called respectively hardware, control and software layers. For the validation of the implemented system, a stainless steel 316L demonstrator has been manufactured, and the required stages have been employed, including part design (CAD), process parameters selection, tool-path definition (CAM) and part manufacturing. This study has shown the feasibility of the adapted machine for additive manufacturing as a controlled process.The authors acknowledge the European Commission for support from project AMAZE (FP7-2012-NMP-ICT-FoF,
project 313781) and the Basque Government for support from project EUSK-ADDI (Etorgai 2014)
- …