Rural issues in urban planning: current trends and reflections

ABSTRACT

While planning has always had an urban emphasis it has also always been concerned with urban–rural linkages and the interactions between urban and rural as well as with the people, economy, and environment of rural places. This symposium issue of International Planning Studies presents recent scholarship on rural planning from around the world.     

Modelling and economic analysis of gas production from hydrates by depressurization method

Gas production from a hydrate reservoir involves decomposition of the solid hydrate. An analytical model is developed to predict reservoir performance for gas production by the depressurization method from a hydrate reservoir containing associated free gas. The model is developed by combining the intrinsic kinetics of hydrate decomposition, which is of interest to chemical engineers, with gas inflow performance relationship and material balance equations. An economic analysis model is also developed and incorporated with the reservoir performance model. These models are used in a case study of gas production from a hydrate reservoir in the Alaskan North Slope. The results show that gas transportation cost is the main factor controlling feasibility of commercial gas production. The hydrate zone contributes significantly to overall reservoir performance by arresting pressure decline and maintaining gas production rate.     

AlON: A brief history of its emergence and evolution

In the early 1970s in Japan, the United States and France it was found that additions of nitrogen into aluminum oxide resulted in new spinel-like phases. At about the same time there was much increased interest in oxynitrides, stimulated by Professor K. Jack in the UK and Y. Oyama in Japan. Following these activities a major research program in this area was initiated at the Army Materials and Mechanics Research Center in Watertown, Massachusetts in 1974. These efforts resulted in the first complete Al₂O₃–AlN phase equilibrium diagram and a process to reactively sinter to nearly full density, translucent aluminum oxynitride spinel ceramic, which was named AlON. Subsequently, the Raytheon Company further developed AlON into a highly transparent material (ALON?) with many applications including transparent armor and EM domes and windows, among others—the technology was recently transferred to the Surmet Corporation. This paper will review the early history, phase equilibrium, crystal chemistry, and properties of this material, along with more recent work in our laboratory on transient liquid phase sintering and new data on lattice parameter measurements. In addition, recent results of collaborative work on AlON's dynamic mechanical properties using plate impact, Kolsky bar and edge-on impact (EoI) experimental techniques, including preliminary modeling at the microstructural scale of AlON in the EoI test, will be presented.     

COMPOSITIONAL ANALYSIS OF NORTH SEA OILS

The molar fluid composition of either the reservoir fluid or the well stream is determined by combining the true boiling point (TBP') distillation data with gas chromatographic (GC) analysis of the light ends. For the purpose of thermodynamic simulation of phase behavior of petroleum reservoir fluids, in addition to the compositional data, physical properties of the pseudo fractions, i.e. density and molecular weight are required. A major drawback of the TBP distillation is the fact that the fractions contain typically 20 -30 % of the material outside the defined boiling range. Another significant issue is the use of generalized density and molecular weight data in the absence of experimentally determined values. This can introduce major inaccuracies in the phase behavior calculations because the generalized value of density and molecular weight significantly differ in each oil based on the paraffin-naphthene-aromatic distribution and its geographic origin.

In this work we have performed the true TBP distillation of 7 stabilized North Sea oil samples. All the oils were distilled from carbon number 6 to 19 and the distillation was terminated at C₂₀₊, which was termed as the residue. We have performed analysis of the Cm fraction of each oil by gas chromatography. Subsequently, the specific gravity and molecular weights of the TBP fractions were determined and compared with the generalized values, which indicated major differences. In addition, the superiority of the PVT calculations for a volatile oil and a gas condensate using the experimentally determined specific gravity and molecular weight of the pseudo fractions against the generalized properties is also demonstrated.     

Purification and Characterization of Aminopeptidase from Chicken Intestine

ABSTRACT: An aminopeptidase was purified 839-fold with 15% recovery from chicken intestine by a procedure involving ion exchange, gel filtration, hydrophobic interaction and affinity chromatography. The enzyme is a heteridimer of subunits 94000 Da and 66000 Da. The substrate specificity of the enzyme was in the order ala > arg > leu-β-naphthylamide. The enzyme was strongly inhibited by bestatin, puromycin, and 1, 10-phenanthroline. The aminopeptidase showed maximum activity at pH 6 and 40 to 50 °C. The enzyme significantly differs from the hitherto known major classes of aminopeptidases from chicken tissues in terms of molecular weight and biochemical characteristics.     

One-sided ultrasonic inspection technique for the elastic constant determination of advanced anisotropic materials

The subject of anisotropic elastic constant determination with a practical one-sided, multi-mode ultrasonic technique is presented along with comparisons with a more traditional cube cutting technique. Results are presented for destructive static compression tests as well. The Young's Moduli calculated from the measured ultrasonic velocity measurements are shown to compare favorably with those obtained from destructive static compression tests. Limitations of the one-sided method are discussed and further research efforts are also suggested.     

Inelastic response of alumina

This paper investigates the effects of microcracking, plasticity, and strain rate dependent pore closure on the inelastic deformation wave profiles of a low density (3.55 mg/m³) and a high density (3.88 mg/m³) aluminas. This is accomplished by means of numerical simulations of the measured plane shock wave profiles in these aluminas. The wave profiles were generated over a wide range of impact velocities (80 m/s to 2200 m/s). An internal-state-variable based ceramic model was used in the simulations to describe the inelastic strains due to microcracking, microplasticity, and pore collapsing. The microcrack size, number of microflaws, and limiting speed of the crack growth controlled the shape of the inelastic wave portion of the velocity profile at low velocity impact. The porosity content and the strain rate sensitivity parameter did not significantly influence the shapes of the low velocity profiles. However, these two parameters greatly influenced the profile shapes when the ceramic was shocked at high velocities well above the Hugoniot elastic limit. The simulations of high velocity experiments clearly demonstrated the need for describing the pore collapse process in order to match the measured wave profiles.