Contractibility and Asset Ownership: On-Board Computers and Governance in U.S. Trucking

We investigate how the contractibility of actions affecting the value of an asset affects asset ownership. We examine this by testing how on-board computer (OBC) adoption affects truck ownership. We develop and test the proposition that adoption should lead to less ownership by drivers, particularly for hauls where drivers have the greatest incentive to drive in non-optimal ways or engage in rent-seeking behavior. We find evidence in favor: OBC adoption leads to less driver ownership, especially for long hauls and hauls that use specialized trailers. We also find that non-owner drivers with OBCs drive better than those without them. These results suggest that technology-enabled increases in contractibility may lead to less independent contracting and larger firms.

Make Versus Buy in Trucking: Asset Ownership, Job Design and Information

Explaining patterns of asset ownership in the economy is a central goal of both organizational economics and industrial organization. We develop a model of asset ownership in trucking, which we test by examining how the adoption of different classes of on-board computers (OBCs) between 1987 and 1997 influenced whether shippers use their own trucks for hauls or contract with for-hire carriers. We find that OBCs' incentive-improving features pushed hauls toward private carriage, but their resource-allocation-improving features pushed them toward for-hire carriage. We conclude that ownership patterns in trucking reflect the importance of both incomplete contracts (Grossman and Hart (1986)) and of job design and measurement issues (Holmstrom and Milgrom (1994)).

Elemental surface analysis at ambient pressure by electron-induced x-ray fluorescence

The development of a portable surface elemental analysis tool, based on the excitation of characteristic x rays from samples at ambient pressure with a focused electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major attributes of this instrument include rapid (several minutes) spectrum acquisition, nondestructive evaluation of elemental composition, no sample preparation, and high-to-medium (several hundreds µm) spatial resolution. The instrument proof-of-principle has been demonstrated in a laboratory setup by obtaining energy dispersive x-ray spectra from metal and mineral samples

A quantum Stirling heat engine operating in finite time

In a quantum Stirling heat engine, the heat exchanged with two thermal baths is partly utilized for performing work by redistributing the energy levels of the working substance. We analyze the thermodynamics of a quantum Stirling engine operating in finite time. We develop a model in which a time-dependent potential barrier changes the energy-level structure of the working substance. The process takes place under a constant interaction with the thermal bath. We further show that in the limit of slow operation of the cycle and low temperature, the efficiency of such an engine approaches Carnot efficiency. We also show that the maximum output power , for the strokes that affect the energy levels, is obtained at an intermediate operating speed, demonstrating the importance of a finite-time analysis.Comment: 11 pages, 8 figure

Biochemical genetic profile of the Indian mackerel Rastreliger kanagurta of mud bank and post-mud bank period

An attempt was made to study the genetic profile of the Indian mackerel Rastrelliger kanagurta, an economically important fish species of India. The genetic profile of the mackerel caught during the mud bank period was compared to that of the post mud bank period

Ghosts- and Tachyon-Free Regions of the Randall-Sundrum Model Parameter Space

Model building within the Randall-Sundrum (RS) framework generally involves placing the Standard Model fields in the bulk. Such fields may possess non-zero values for their associated brane-localized kinetic terms (BLKTs) in addition to possible bulk mass parameters. In this paper we clearly identify the regions of the RS model parameter space where the presence of bulk mass terms and BLKTs yield a setup which is free from both ghost and tachyon instabilities. Such physically acceptable parameter space regions can then be used to construct realistic and phenomenologically viable RS models.Comment: Latex, 30 pages, 2 figure

Assessment of the Harmonic Balance Method for Rotor Blade Performance Predictions

This paper presents an assessment of the harmonic balance method for rotor blade performance predictions. The harmonic balance method within the HMB3 solver of Glasgow University has been extended to the use with overset grids, and results are presented for the PSP and AH-64A rotor blades in hover and forward flight. The predictions are compared with results from steady-state and time marching simulations. In particular, the harmonic balance method is assessed for capturing key flow features, such as the strength of the advancing blade shockwave and retreating side blade dynamic stall. The limitations of the method are also discussed. The findings show that the harmonic balance method is a promising alternative to time-marching simulations due to a significant reduction in computational costs, leading to the potential use of high-fidelity Navier-Stokes methods in optimisation studies