Concentrations and dietary exposure to polycyclic aromatic hydrocarbons (PAHs) from grilled and smoked foods

We investigated the concentrations and profiles of 16 priority polycyclic aromatic hydrocarbons (PAHs) in various grilled and smoked foods and estimated the dietary exposure of Kuwaiti children, adolescent and adult populations. Results indicated that non-carcinogenic PAHs were present at high proportions (60–100%) with phenanthrene showing the highest mean concentration (54.9 μg kg^?1, 37.1% of the total PAH concentrations). Among the genotoxic PAHs (PAH8), chrysene (4.88 μg kg^?1, 3.29%) and benz[a]anthracene (2.27 μg kg^?1, 1.53%) showed the highest mean values. Meat tikka contained the highest mean concentrations of benzo[a]pyrene (BaP) (2.48 μg kg^?1), total genotoxic PAHs (42.9 μg kg^?1), total PAHs (ΣPAHs) (648 μg kg^?1) and total benzo[a]pyrene equivalents (ΣBaPeq) (6.02 μg kg^?1). High levels of genotoxic PAHs were detected in grilled vegetables (21.1 μg kg^?1), shish tauk (20.5 μg kg^?1) and whole grilled chicken (20.3 μg kg^?1) samples. However, meat and chicken shawerma samples had low levels of PAH8. Meat tikka (437 ng/day, 641 ng/day), whole grilled chicken (160 ng/day, 241 ng/day), grilled vegetables (120 ng/day, 166 ng/day), meat burger (114 ng/day, 92.7 ng/day) were the major contributors to the daily intake of PAH8 in children/adolescent and adult populations, respectively. The total mean dietary intakes for children/adolescents and adults for BaP (8.09 ng/day, 9.20 ng/day), PAH8 (84.2 ng/day, 95.7 ng/day), ∑PAHs (974 ng/day, 1108 ng/day) and ∑BaPeq (14.8 ng/day, 16.8 ng/day) were comparable. Cancer risks for Kuwaiti children/adolescents and adults from dietary intake of ΣBaPeq from the animal-origin foods were determined to be 2.63/10⁷ and 9.3/10⁷, respectively.     

Simulation of an Atmospheric Residue Desulfurization Unit by Quasi-Steady State Modeling

The current trend in petroleum refining is to maximize the conversion of the bottom of the barrel to improve the profitability of the refinery. Atmospheric residue desulfurization (ARDS) plays a key role in this, especially, when processing crudes with moderate to high sulfur contents. A deterministic quasi-steady state model has been developed to simulate the long term behavior of the reaction section of an atmospheric residue desulfurization (ARDS) unit, consisting of four co-current catalytic trickle bed reactors in series. The model uses the properties of the feedstock and the catalyst and is capable of simulating profiles of sulfur, coke, and metal depositions and the temperature along the reactors, taking into account also catalyst deactivation. Hydrogen quenching has also been simulated and simulation results predict all the essentials of the long term behavior of both experimental and industrial scale ARDS reactors satisfactorily. Comparing the simulation results with actual commercial data, the model predicted perfectly the middle part of the run. The model is unable to simulate the End-of-Run conditions due to pore mouth plugging phenomenon.     

Estimation of Fracture–Matrix Transport Properties from Saturation Profiles Using a Multivariate Automatic History Matching Method

Abstract

This study focuses on the development and implementation of a numerical model of multiphase flow in a fractured core sample by describing the capillary pressure–relative permeability characteristics. An automated history matching approach is proposed to determine relative permeability and capillary pressure curves simultaneously for both matrix and fracture consistent with a core flood reservoir model performance, which relies on a commercial reservoir simulator coupled with an optimization protocol. The results indicate that the proposed approach successfully predicts relative permeability and capillary pressure curves of a fractured core sample and provides a foundation for field-scale history matching with simultaneous estimation of transport properties.     

Structured extension of COBOL for handling data bases

The most important aspects of a modest data base management system are described on the basis of our experiences in implementing it. Data structuring facilities of the system include two basic data structures: lists and binary search trees; and a simple rule of their top-down composition. The class of structures that may be obtained this way is rather restricted in comparison with the CODASYL proposal, but still fairly powerfull and permits definition and easy implementation of an elegant data manipulation language (DML). Operations of the DML have simple syntax and semantics and allow implementation in which the structure of the data base is protected against illegal actions on the part of the programmer. Since implementation of the system requires some modest effort, we offer it as an experiment which shows how existing software facilities can be extended in simple and still essential ways, for applications where all the generality of general data base management systems is not really necessary. Design of the system was motivated by the work of Schneidermann and Scheuerman on structured data structures and it contains several important clarifications and improvements of their suggestions, together with implementation aspects.     

Functional modelling of volatility in the Swedish limit order book

The publicly available electronic limit order book at the Stockholm Stock Exchange consists of five levels of prices and quantities of a given stock with a bid and ask side. All changes in the book during one day can be recorded with a time quote. Studying the variation of the quoted price returns as a function of quantity is discussed. In particular, discovering and modelling dynamic behaviours in the volatility of prices and liquidity measures are considered. Applying a functional approach, estimation of the volatility dynamics of the spreads, created as differences between the ask and bid prices, is presented through a case study. For that purpose two-step estimation of functional linear models is used, extending this method to a time series context.     

Genericity in Java: persistent and database systems implications

Lack of parametric polymorphism has been a major obstacle for making Java a viable database programming language. Regrettably, a recently accepted solution for genericity in Java 5.0 has far-reaching negative implications for persistent and database systems because of static and dynamic type violations. Severe implications occur in typical database transactions when processing a variety of database collections. Well-known approaches to persistence in Java, including Java’s own persistence mechanism, do not perform correctly due to incorrect dynamic type information that gets promoted to persistence along with objects. Dynamic checking of types of objects fetched from the persistent store may now lead to unexpected type violations. Further problems occur in reflective transactions as Java Core Reflection now allows dynamic type violations without detecting them or throwing standard exceptions. All of this shows that extending Java with parametric polymorphism has not made Java a more viable database programming language. Both legacy systems, such as those based on the Java binding of the ODMG or JDO, and future Java-related persistent and database technologies will be affected. The source of these problems is in an implementation idiom called type erasure. This paper provides formal proofs of the above implications of type erasure along with specific samples of code in Java 5.0 illustrating these violations. The limitations of the virtual platform and extensions required for persistent systems to solve this problem are also elaborated.     

Use of the wavelet transform in optimal receiver design

Wavelet transforms as they apply to optimal receiver design are studied. We start with an overview of the Karhunen-Loéve transform and explore the relationship between wavelet bases and the Karhunen-Loéve transform. We show that the dyadic wavelet basic can constitute the eigenfunction basis of a random process. With the help of this foundation, the design of an optimal receiver by the use of a the wavelet expansion is described. The relationship of this receiver to the wavelet-transform-based adaptive filter is also established.     

The composite fuzzy reliability index of power systems

This paper describes a method for fuzzy calculation of power system reliability. It introduces a composite fuzzy security and fuzzy adequacy indices encompassing the power system segments of generation, transmission, and the segment of load nodes. The fuzzy security index is determined by the security membership grades of the power system components which are found to be the worst in their segments. The fuzzy adequacy index is based on the adequacy indices of generation, transmission, and transmission integration segments. The composite fuzzy reliability index enables the system operator to have a continuous insight into the distance between the power system's actual state and the closest unreliable state by tracking the system's components with the lowest security and adequacy membership grades of the respective segments. The algorithm has been tested on the models of the IEEE Three Area RTS-96 and Bosnia-Herzegovina power systems.     

Moisture effect on selected polymer‐based membranes used for waterproofing building basements

As part of a comprehensive study to develop national guidelines for waterproofing building basements in Kuwait, physical properties of locally available waterproofing materials were examined and the performance of selected polymer‐based membranes under continuous exposure to moisture, as in actual service conditions, were evaluated. Five categories of waterproofing materials, consisting of bitumen membranes, plastic membranes, rubber membranes, fluid‐applied materials, and cementitous materials were tested in accordance with American Society for Testing and Materials (ASTM) standard test methods. Sulphate and chloride concentrations in soil and groundwater in Kuwait are generally high. The rise in groundwater level in Kuwait is a predominant cause of water leakage into building basements in residential areas. The effect of moisture on the performance of waterproofing materials was evaluated under simulated conditions of continuous exposure to groundwater. The test results indicated that under continuous exposure to salty water, the moisture rather than the salts seems to have a detrimental effect on the physical properties of some of the waterproofing materials. The results also indicated that oxidized bitumen membranes are not suitable for waterproofing building basements. The performance of the two polymer modified bituminous membranes evaluated in the study indicates that waterproofing materials belonging to the same category may have significant differences in specific properties. POLYM. COMPOS., 26:276–286, 2005. © 2005 Society of Plastics Engineers     

A quantized water cycle optimization algorithm for antenna array synthesis by using digital phase shifters

In this article, a quantized water cycle algorithm (QWCA) is used for the antenna array pattern synthesis with low side‐lobe levels (SLLs) and nulls at desired directions by using four‐bit digital phase shifters. In addition to the standard features as a metaheuristic algorithm, QWCA has an internal quantization mechanism and a precalculated array factor method. The latter provides an accelerated procedure to QWCA under favour of the digitized values that can be stored in a three‐dimensional array. This acceleration is based on the reality that the accessing data in the memory need less time than the usage of the mathematical functions throughout the optimization process. The internal quantization mechanism of QWCA is utilized to achieve digital values matching to the discrete values of the phase shifter instead of the simple rounding up/down routines after optimization. The numerical results showed that QWCA can obtain very good SLLs and null depth levels (NDLs) on the synthesized pattern. Moreover, the results are achieved in remarkably short optimization times. SLL and NDL values obtained by QWCA are also compared with the available literature values. The comparisons reveal that QWCA is able to produce better results than the other compared alternatives. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:21–29, 2015.