Scale and scope economies and the efficient vertical and horizontal configuration of the water industry:a survey of the literature

This paper surveys the literature on scale and scope economies in the water and sewerage industry. The magnitude of scale and scope economies determines the cost efficient configuration of any industry. In the case of a regulated sector, reliable estimates of these economies are relevant to inform reform proposals that promote vertical (un)bundling and mergers. The empirical evidence allows some general conclusions. First, there is considerable evidence for the existence of vertical scope economies between upstream water production and distribution. Second, there is only mixed evidence on the existence of (dis)economies of scope between water and sewerage activities. Third, economies of scale exist up to certain output level, and diseconomies of scale arise if the company increases its size beyond this level. However, the optimal scale of utilities also appears to vary considerably between countries. Finally, we briefly consider the implications of our findings for water pricing and point to several directions for necessary future empirical research on the measurement of these economies, and explaining their cross country variation.

Vertical and horizontal scope economies in the regulated US electricity power industry

This paper investigates vertical economies between generation and distribution of electric power, and horizontal economies between different types of power generation in the U.S. electric utility industry. Our quadratic cost function model includes three generation output measures (hydro, nuclear and fossil fuels), which allows us to analyze the effect that generation mix has on vertical economies. Our results provide (sample mean) estimates of vertical economies of 8.1% and horizontal economies of 5.4%. An extensive sensitivity analysis is used to show how the scope measures vary across alternative model specifications and firm types. © 2012 Blackwell Publishing Ltd and the Editorial Board of The Journal of Industrial Economics.

Measuring economies of horizontal and vertical integration in the US electric power industry:how costly is unbundling?

This research employs econometric analysis on a cross section of American electricity companies in order to study the cost implications associated with unbundling the operations of integrated companies into vertically and/or horizontally separated companies. Focusing on the representative sample average firm, we find that complete horizontal and vertical disintegration resulting in the creation of separate nuclear, conventional, and hydro electric generation companies as well as a separate firm distributing power to final consumers, results in a statistically significant 13.5 percent increase in costs. Maintaining a horizontally integrated generator producing nuclear, conventional, and hydro electric generation while imposing vertical separation by creating a stand alone distribution company, results in a lower but still substantial and statistically significant cost penalty amounting to an 8.1 % increase in costs relative to a fully integrated structure. As these results imply that a vertically separated but horizontally integrated generation firm would need to reduce the costs of generation by 11% just to recoup the cost increases associated with vertical separation, even the costs associated with just vertical unbundling are quite substantial. Our paper is also the first academic paper we are aware of that systematically considers the impact of generation mix on vertical, horizontal, and overall scope economies. As a result, we are able to demonstrate that the estimated cost of unbundling in the electricity sector is substantially influenced by generation mix. Thus, for example, we find evidence of strong vertical integration economies between nuclear and conventional generation, but little evidence for vertical integration benefits between hydro generation and the distribution of power. In contrast, we find strong evidence suggesting the presence of substantial horizontal integration economies associated with the joint production of hydro generation with nuclear and/or conventional fossil fuel generation. These results are significant because they indicate that the cost of unbundling the electricity sector will differ substantially in different systems, meaning that a blanket regulatory policy with regard to the appropriateness of vertical and horizontal unbundling is likely to be inappropriate.

FDI horizontal and vertical effects on local firm technical efficiency

Differencing from previous studies on foreign direct investment (FDI) spillovers to domestic enterprises which mainly focus on productivity, in this paper we take a different perspective by analysing the impacts of FDI to technical efficiency of domestic firms. The paper goes beyond the current literature to shed some light on the spillover effects of FDI to technical efficiency of small and medium enterprises in a developing country. By exploiting a firm-level panel dataset and using SFA models following Battese and Coelli (1995), the paper is able to analyse horizontal spillovers through imitation and competition and labour mobility as well as vertical spillovers through backward and forward linkages on technical efficiency. The paper contributes to the understanding of potential effects on foreign invested enterprises on domestic economy in general and local enterprises performance in particular. Thus it importantly assists policy making by the government of developing countries, where FDI is believed to create technical spillovers on domestic enterprises.

Asymptotic theory of wall-attached convection in a horizontal fluid layer with a vertical magnetic field

A horizontal fluid layer heated from below in the presence of a vertical magnetic field is considered. A simple asymptotic analysis is presented which demonstrates that a convection mode attached to the side walls of the layer sets in at Rayleigh numbers much below those required for the onset of convection in the bulk of the layer. The analysis complements an earlier analysis by Houchens [J. Fluid Mech. 469, 189 (2002)] which derived expressions for the critical Rayleigh number for the onset of convection in a vertical cylinder with an axial magnetic field in the cases of two aspect ratios. © 2008 American Institute of Physics.

Horizontal deflection of single particle in a paramagnetic fluid

This paper describes the horizontal deflection behaviour of a single particle in paramagnetic fluids under a high-gradient superconducting magnetic field. A glass box was designed to carry out experiments and test assumptions. It was found that the particles were deflected away from the magnet bore centre and particles with different density and/or susceptibility settled at a certain position on the container floor due to the combined forces of gravity and magneto-Archimedes as well as lateral buoyant (displacement) force. Matlab was chosen to simulate the movement of the particle in the magnetic fluid, the simulation results were in good accordance with experimental data. The results presented here, though, are still very much in their infancy, which could potentially form the basis of a new approach to separating materials based on a combination of density and susceptibility. Graphical abstract: [Figure not available: see fulltext.] © 2014 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Particle separation by horizontal deflection in paramagnetic fluid

This paper describes the horizontal deflection behaviour of the streams of particles in paramagnetic fluids under a high-gradient superconducting magnetic field, which is the continued work on the exploration of particle magneto-Archimedes levitation. Based on the previous work on the horizontal deflection of a single particle, a glass box and collector had been designed to observe the movement of particle group in paramagnetic fluids. To get the exact separation efficiency, the method of "sink-float" involved the high density fluid polytungstate (dense medium separation) and MLA (Mineral Liberation Analyser) was performed. It was found that the particles were deflected and settled at certain positions on the container floor due to the combined forces of gravity and magneto-Archimedes forces as well as a lateral buoyancy (displacement) force. Mineral particles with different densities and susceptibilities could be deflected to different positions, thus producing groups of similar types of particles. The work described here, although in its infancy, could form the basis of new approach of separating particles based on a combination of susceptibility and density. © 2014 Elsevier B.V.

Bifunctional role for VEGF-induced heme oxygenase-1 in vivo:induction of angiogenesis and inhibition of leukocytic infiltration

Heme-oxygenases (HOs) catalyze the conversion of heme into carbon monoxide and biliverdin. HO-1 is induced during hypoxia, ischemia/reperfusion, and inflammation, providing cytoprotection and inhibiting leukocyte migration to inflammatory sites. Although in vitro studies have suggested an additional role for HO-1 in angiogenesis, the relevance of this in vivo remains unknown. We investigated the involvement of HO-1 in angiogenesis in vitro and in vivo. Vascular endothelial growth factor (VEGF) induced prolonged HO-1 expression and activity in human endothelial cells and HO-1 inhibition abrogated VEGF-driven angiogenesis. Two murine models of angiogenesis were used: (1) angiogenesis initiated by addition of VEGF to Matrigel and (2) a lipopolysaccharide (LPS)-induced model of inflammatory angiogenesis in which angiogenesis is secondary to leukocyte invasion. Pharmacologic inhibition of HO-1 induced marked leukocytic infiltration that enhanced VEGF-induced angiogenesis. However, in the presence of an anti-CD18 monoclonal antibody (mAb) to block leukocyte migration, VEGF-induced angiogenesis was significantly inhibited by HO-1 antagonists. Furthermore, in the LPS-induced model of inflammatory angiogenesis, induction of HO-1 with cobalt protoporphyrin significantly inhibited leukocyte invasion into LPS-conditioned Matrigel and thus prevented the subsequent angiogenesis. We therefore propose that during chronic inflammation HO-1 has 2 roles: first, an anti-inflammatory action inhibiting leukocyte infiltration; and second, promotion of VEGF-driven noninflammatory angiogenesis that facilitates tissue repair.

Mathematical Model and Simulation of a Pneumatic Apparatus for In-Drilling Alignment of an Inertial Navigation Unit during Horizontal Well Drilling

Conventional methods in horizontal drilling processes incorporate magnetic surveying techniques for determining the position and orientation of the bottom-hole assembly (BHA). Such means result in an increased weight of the drilling assembly, higher cost due to the use of non-magnetic collars necessary for the shielding of the magnetometers, and significant errors in the position of the drilling bit. A fiber-optic gyroscope (FOG) based inertial navigation system (INS) has been proposed as an alternative to magnetometer -based downhole surveying. The utilizing of a tactical-grade FOG based surveying system in the harsh downhole environment has been shown to be theoretically feasible, yielding a significant BHA position error reduction (less than 100m over a 2-h experiment). To limit the growing errors of the INS, an in-drilling alignment (IDA) method for the INS has been proposed. This article aims at describing a simple, pneumatics-based design of the IDA apparatus and its implementation downhole. A mathematical model of the setup is developed and tested with Bloodshed Dev-C++. The simulations demonstrate a simple, low cost and feasible IDA apparatus.

A comparison of in situ constant and falling head permeameter tests to assess the distribution of clogging within horizontal subsurface flow constructed wetlands

Clogging is the main operational problem associated with horizontal subsurface flow constructed wetlands (HSSF CWs). The measurement of saturated hydraulic conductivity has proven to be a suitable technique to assess clogging within HSSF CWs. The vertical and horizontal distribution of hydraulic conductivity was assessed in two full-scale HSSF CWs by using two different in situ permeameter methods (falling head (FH) and constant head (CH) methods). Horizontal hydraulic conductivity profiles showed that both methods are correlated by a power function (FH= CH 0.7821, r 2=0.76) within the recorded range of hydraulic conductivities (0-70 m/day). However, the FH method provided lower values of hydraulic conductivity than the CH method (one to three times lower). Despite discrepancies between the magnitudes of reported readings, the relative distribution of clogging obtained via both methods was similar. Therefore, both methods are useful when exploring the general distribution of clogging and, specially, the assessment of clogged areas originated from preferential flow paths within full-scale HSSF CWs. Discrepancy between methods (either in magnitude and pattern) aroused from the vertical hydraulic conductivity profiles under highly clogged conditions. It is believed this can be attributed to procedural differences between the methods, such as the method of permeameter insertion (twisting versus hammering). Results from both methods suggest that clogging develops along the shortest distance between water input and output. Results also evidence that the design and maintenance of inlet distributors and outlet collectors appear to have a great influence on the pattern of clogging, and hence the asset lifetime of HSSF CWs. © Springer Science+Business Media B.V. 2011.

A finite element approach to modelling the hydrological regime in horizontal subsurface flow constructed wetlands for wastewater treatment

A Finite Element Analysis (FEA) model is used to explore the relationship between clogging and hydraulics that occurs in Horizontal Subsurface Flow Treatment Wetlands (HSSF TWs) in the United Kingdom (UK). Clogging is assumed to be caused by particle transport and an existing single collector efficiency model is implemented to describe this behaviour. The flow model was validated against HSSF TW survey results obtained from the literature. The model successfully simulated the influence of overland flow on hydrodynamics, and the interaction between vertical flow through the low permeability surface layer and the horizontal flow of the saturated water table. The clogging model described the development of clogging within the system but under-predicted the extent of clogging which occurred over 15 years. This is because important clogging mechanisms were not considered by the model, such as biomass growth and vegetation establishment. The model showed the usefulness of FEA for linking hydraulic and clogging phenomenon in HSSF TWs and could be extended to include treatment processes. © 2011 Springer Science+Business Media B.V.

On the role of surface roughness in the aerodynamic performance and energy conversion of horizontal wind turbine blades:a review

Summary: Renewable energy is one of the main pillars of sustainable development, especially in developing economies. Increasing energy demand and the limitation of fossil fuel reserves make the use of renewable energy essential for sustainable development. Wind energy is considered to be one of the most important resources of renewable energy. In North African countries, such as Egypt, wind energy has an enormous potential; however, it faces quite a number of technical challenges related to the performance of wind turbines in the Saharan environment. Seasonal sand storms affect the performance of wind turbines in many ways, one of which is increasing the wind turbine aerodynamic resistance through the increase of blade surface roughness. The power loss because of blade surface deterioration is significant in wind turbines. The surface roughness of wind turbine blades deteriorates because of several environmental conditions such as ice or sand. This paper is the first review on the topic of surface roughness effects on the performance of horizontal-axis wind turbines. The review covers the numerical simulation and experimental studies as well as discussing the present research trends to develop a roadmap for better understanding and improvement of wind turbine performance in deleterious environments.

A horizontális és vertikális ágazaton belüli agrárkereskedelem meghatározó tényezői az EU új tagországaiban (Determinants of horizontal and vertical intra-industry agri-food trade in the new EU member-states)

Az ágazaton belüli kereskedelem egyre komolyabb szerepet tölt be a nemzetközi kereskedelemben, mind ez idáig azonban kevés mezőgazdasági témájú elemzés készült e témában. A cikk célja a horizontális és vertikális ágazaton belüli agrárkereskedelem meghatározó tényezőinek azonosítása az új tagországok és az EU–27 közötti kereskedelemben 1999–2010 között. Ehhez a szerző statikus és dinamikus panelmódszereket alkalmaz különböző specifikációkkal. Eredményei szerint a tényezőellátottság a horizontális ágazaton belüli kereskedelemmel negatív, míg a vertikálissal pozitív kapcsolatban áll. Az országok mérete az ágazaton belüli kereskedelem mindkét oldalával pozitívan, míg a távolság negatívan korrelál. Az eredmények azt is kimutatják, hogy az ágazaton belüli kereskedelem mértéke nagyobb, ha egy új tagország a kelet-közép-európai régióba exportál, és az is világossá vált, hogy az EU-csatlakozás pozitívan hatott az ágazaton belüli kereskedelemre, jelezve a gazdasági integráció kereskedelemösztönző szerepét. _____ Intra-industry trade (IIT) has a growing role in international trade, although the number of papers on its agricultural aspects is limited. This article identifies the determinants of horizontal and vertical intra-industry agri-food trade between new member-states (NMS) and the EU27 in 1999-2010, by applying to panel data static and dynamic models with different specifications. The results show that factor endowments are negatively related to agri-food horizontal intra-industry trade (HIIT), but positively to vertical intra-industry trade (VIIT). Economic size is positively and significantly related to both, while distance and IIT are found to be negatively related. This also suggests that HIIT and VIIT are greater if an NMS exports agri-food products to another NMS, while EU accession has had positive and significant impacts on both HIIT and VIIT, which suggests that economic integration fosters IIT.

Horizontal diversity of higher education institutions. The case of Hungary – in European context

In the European Higher Education Area the diversification of higher education is considered to be an emphasized value, a guarantee of creativity. The various institutional rankings are the displays of vertical diversity, but in parallel with these, there is an increasing attention directed at horizontal diversity, the entirety of the institutions' activities. The European Mapping Project (U-map) undertook this challenge. The paper presents the research program, which is an attempt to adapt the U-map model to Hungary. According to the results, the U-map method which was intended for application on an international level, is very useful in the identification of the main groups of institutions in a specific national higher education system as well, and may provide a basis for the creation of institutional strategies and the development of the institutions’ network.

Country-specific determinants of horizontal and vertical intra-industry agri-food trade: the case of Bulgaria and Romania

The article analyses patterns and country-specific determinants of agri-food trade of Bulgaria and Romania with the European Union. As literature focusing on agricultural aspects of the topic is limited, the paper seeks to contribute to the literature by providing up to date results and suggestions as well as by identifying the determinants of horizontal and vertical intra-industry trade of the Bulgaria and Romania after EU accession. Results suggest that intra-industry agri-food trade is mainly of vertical nature, referring to trade of different quality products. Results verify that determinants of horizontal and vertical IIT are similar and suggest that economic size and FDI are positively, while factor endowments and distance are negatively related to both sides of IIT. Results are mainly in line with the majority of empirical literature in the field.