HYDROCARBON SEEPAGE GENERATION AND MIGRATION IN THE SOUTHERN GULF OF SUEZ, EGYPT: INSIGHTS FROM BIOMARKER CHARACTERISTICS AND SOURCE ROCK MODELLING

Active oil seepages in the Gebel El-Zeit area (southern Gulf of Suez, Egypt) occur in fault zones on the western flank of the East Zeit Basin. Gas chromatography-mass spectrometry indicates that these oils are rich in tricyclic terpanes and extended hopanes with few diasteranes. These characteristics are typical of oils derived from marine siliciclastic source rocks; an input of terrestrial angiosperms material is indicated by the very high oleanane index of 32.65% and the low gammacerane index of 6.28%. The molecular maturity parameter C₂₉ααα cholestane [20S/(20S+20R)] is < 0.5 indicating that these oils were generated at relatively low thermal maturities. The seepage oils resemble Miocene crude oils in the East Zeit Basin which are believed to be generated from the Lower Miocene Rudeis Shale. Burial history modelling indicates that oil generation from this unit began at around 3–4 Ma at vitrinite reflectance levels of Ro%=0.60–0.85. This implies extensive lateral and vertical migration has taken place for the generated oil to reach the surface. Alternatively, the seepage oils may be sourced by leakage from preexisting accumulations.     

Assessing critical functional and non-functional requirements for web-based procurement systems: a comprehensive survey

World Wide Web (WWW)-based electronic commerce has emerged as a mean to conduct business transactions that were previously handled through traditional interorganizational systems, phone, fax, on-site visits, or mail. Today, electronic procurement (e-procurement) accounts for most of the volume and value of the business transactions conducted over the Internet. As of yet, however, little or no research has assessed the functional and non-functional requirements sought for the WWW-based systems used to support the procurement process. This paper, presents findings of a survey of 133 corporate buyers from about 130 companies on the use of readily available web-based systems for business-to-business transactions and the requirements perceived to be critical to the effective support of supply chain operations.     

Numerical Modeling of Conductive Particle Trajectories in Roll-Type Corona-Electrostatic Separators

Several attempts have already been made to simulate particle trajectories in roll-type electrostatic separators. However, the predictive value of the results is limited by an excessive number of simplifying assumptions regarding the electric field distribution, as well as particle charging and discharging mechanisms. The present work is aimed at improving the existing models by taking into account: (1) the non-uniformity of the electric field in the active zone of the separator and (2) the effect of spark discharges occurring between the electrodes. Based on previous observations, the conductive particles were assumed to lift-off when no longer exposed to corona discharge. The numerical simulations were performed for particles of various sizes. The electric field was computed in each point of the trajectory using a finite element program. It was found that: (1) some of the smaller particles impact the static electrode and are deviated to the middling compartment of the collector and (2) field annealing which accompanies spark discharges significantly affects the trajectories of conductive particles. The results of this study could guide the design of new electrostatic separation applications.     

On the Achievable Rates of Multiband Ultra-Wideband Systems

In this work we study the achievable rates of memoryless signaling strategies adapted to ultra-wideband (UWB) multipath fading channels. We focus on strategies that do not have explicit knowledge of the instentaneous channel realization, but may have knowledge of the channel statistics. We evaluate the average mutual information of the general binary flash-signaling rates as a function of channel statistics and derive random coding bounds for m-ary PPM using different noncoherent receivers as well as an imperfect coherent receiver. Then we extend the results to multiband m-PPM signaling and show that for data rates on the order of 400 Mbits/s, at 4 m distance between the transmitter and the receiver, can be achieved using simple noncoherent receivers.     

Computing Large Deformation Metric Mappings via Geodesic Flows of Diffeomorphisms

This paper examine the Euler-Lagrange equations for the solution of the large deformation diffeomorphic metric mapping problem studied in Dupuis et al. (1998) and Trouvé (1995) in which two images I ₀, I ₁ are given and connected via the diffeomorphic change of coordinates I ₀○ϕ⁻¹=I ₁ where ϕ=Φ₁ is the end point at t= 1 of curve Φ _t , t∈[0, 1] satisfying ^.Φ _t =v _t (Φ _t ), t∈ [0,1] with Φ₀=id. The variational problem takes the form

Effect of growth parameters on the heteroepitaxy of 3C-SiC on 6H-SiC substrate by chemical vapor deposition

Epitaxial 3C-SiC(1 1 1) films were grown on 6H-SiC(0 0 0 1) Si face on axis substrates by chemical vapor deposition under H₂, SiH₄ and C₃H₈ in a cold wall vertical reactor. Two temperatures were studied (1450 and 1700 °C) with various C/Si ratio and deposition time. It was found that under conditions giving high lateral growth (low C/Si and/or high temperature), homoepitaxial growth occurred even at temperatures as low as 1450 °C. For other conditions, the 3C-SiC polytype was detected and always together with the formation of double positioning boundaries whose density was found to depend on the growth conditions but not on the initial surface reconstruction. Single domain enlargement was observed when growth was performed at 1700 °C over a nucleation layer grown at 1450 °C.     

Relationship between J-integral and averaged strain-energy density for U-notches in the case of large control volume under Mode I loading

The main purpose of this technical note is to present a relationship between J-integral and averaged strain-energy density () in U-notches under Mode I loading for brittle or quasi-brittle materials. In this work, control volume includes the rectilinear edge of the notch in addition to semi-circular arc of the notch root. A dimensionless function (f) between J and has been presented in this paper. Finite element analysis has been used for verification. It is found that this relationship is identical for tension or bending loading.