Specialisation, diversification, size and technical efficiency in ports: an empirical analysis using frontier techniques

This paper explores the relationship between output specialisation, diversification, size and technical efficiency in ports. Using a sample of Spanish port authorities observed over the period 1993-2012, we calculate a normalised Herfindahl-Hirschman index of overall specialisation and indices of relative specialisation in the individual cargoes. An output distance frontier is estimated using non-parametric Data Envelopment Analysis techniques to calculate technical efficiency. These efficiency scores are then used to test that relationship with a bootstrapped truncated regression. We find that both overall and relative output specialisation have a positive influence on technical efficiency. Moreover, the positive effects of specialisation on technical efficiency is reinforced for larger ports, which are in a better position to take advantage of economies of scale and which can also attract different types of cargo (enjoying also economies of scope) and therefore protect themselves from adverse demand conditions. Our results underline the trade-off for smaller port authorities between efficiency gains from specialisation and their vulnerability to market conditions for their main output

The final frontier : the integration of banking and commerce. Part 1, the likely outcome of eliminating the barrier

Exploring the potential effects of removing the legal barriers between banks and commercial firms, this article surveys economic theory as well as experience in other developed countries and in U.S. nonbank conglomerates.Banks and banking ; Banking law

Summary of Supersonic Jet and Rocket Noise

This paper summarizes a two-part special session, “Supersonic Jet and Rocket Noise,” which was held during the 174th Meeting of the Acoustical Society of America in New Orleans, Louisiana. The sessions were cosponsored by the Noise and Physical Acoustics Technical Committees and consisted of talks by government, academic, and industry researchers from institutions in the United States, Japan, France, and India. The sessions described analytical, computational, and experimental approaches to both fundamental and applied problems on model and full-scale jets and rocket exhaust plumes

Characterization of High-Power Rocket and Jet Noise Using Near-Field Acoustical Holography

Structural fatigue, hearing damage, and community disturbances are all consequences of rocket and jet noise, especially as they become more powerful. Noise-reduction schemes require accurate characterization of the noise sources within rocket plumes and jets. Nearfield acoustical holography (NAH) measurements were made to visualize the sound field in the jet exhaust region of an F-22 Raptor. This is one of the largest-scale applications of NAH since its development in the 1980s. A scan-based holographic measurement was made using a 90-microphone array with 15 cm regular grid spacing, for four engine power settings. The array was scanned through 93 measurement positions, along three different planes in a region near 7 m from the jet centerline and 23 m downstream. In addition, 50 fixed reference microphones were placed along the ground 11.6 m from the jet centerline, spanning 30.8 m. The reference microphones have been used to perform virtual coherence on the measurement planes. Statistically-optimized NAH (SONAH) has been used to backpropagate the sound field to the source region for low frequencies, and to identify jet noise characteristics. Ground reflection interference and other non-ideal measurement conditions must be dealt with. Details relating to jet coherence lengths and their relation to reference microphone requirements will be discussed. Preliminary results of this ongoing work will be presented. [Work supported by Air Force SBIR.

Synthesis and characterization of nanophase face-centered-cubic titanium

Unalloyed Ti is sputter deposited in the formation of two trilayer films. Each layer within the combinations of Ni-Ti-Ni and Ti-Ni-Ti is less than 0.1 {mu}m thick. High resolution imaging and electron diffraction results are presented for the microstructural characterization of both trilayer films. Nanophase fcc Ti is initially found in crystalline layers grown on Ni whereas hcp Ti is found in layers grown without a Ni epilayer. Conditions are further examined under which the fcc to hcp transition occurs for Ti deposited on Ni

Methanosarcina play an important role in anaerobic co-digestion of the seaweed Ulva lactuca: metagenomics structure and predicted metabolism of functional microbial communities.

Macro-algae represent an ideal resource of third generation biofuels, but their use necessitates a refinement of commonly used anaerobic digestion processes. In a previous study, contrasting mixes of dairy slurry and the macro-alga Ulva lactuca were anaerobically digested in mesophilic continuously stirred tank reactors for 40 weeks. Higher proportions of U. lactuca in the feedstock led to inhibited digestion and rapid accumulation of volatile fatty acids, requiring a reduced organic loading rate. In this study, 16S pyrosequencing was employed to characterise the microbial communities of both the weakest (R1) and strongest (R6) performing reactors from the previous work as they developed over a 39 and 27-week period respectively. Comparing the reactor communities revealed clear differences in taxonomy, predicted metabolic orientation and mechanisms of inhibition, while constrained canonical analysis (CCA) showed ammonia and biogas yield to be the strongest factors differentiating the two reactor communities. Significant biomarker taxa and predicted metabolic activities were identified for viable and failing anaerobic digestion of U. lactuca. Acetoclastic methanogens were inhibited early in R1 operation, followed by a gradual decline of hydrogenotrophic methanogens. Near-total loss of methanogens led to an accumulation of acetic acid that reduced performance of R1, while a slow decline in biogas yield in R6 could be attributed to inhibition of acetogenic rather than methanogenic activity. The improved performance of R6 is likely to have been as a result of the large Methanosarcina population, which enabled rapid removal of acetic acid, providing favourable conditions for substrate degradation