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Fluid bed drying of guarana ( Paullinia cupana HBK) extract: Effect of process factors on caffeine content

admin — Mon, 02 Feb 2009 14:26:52 +0000

The aim of this study was to study the convective drying of the hydroalcoholic extracts obtained from powdered guarana seeds in a spouted bed dryer. The influence of process variables, such as the convective airflow rate, extract feed rate,; air inlet temperature, on the quality of the dry extract was determined using the caffeine; moisture content for the process evaluation. The caffeine content in the alcoholic; dried extracts was determined by capillary gas chromatography. The experiments were performed following a 3[3] factorial design; the data analyzed by response surface. The analysis of dry extract showed that the air; extract feed rates did not significantly affect (25% level) the caffeine content, but that drying temperature is a major factor to consider when the extract is submitted to fluid bed drying. Caffeine losses were significant (1% level) for drying temperatures above 120�C, while moisture content was lower than 3% for temperatures above 120�C. The data showed that there is an optimum temperature for the drying of guarana extracts in spouted beds,; under the conditions used in this study it was 120�C.

Renata S. Pagliarussi1?Jairo K. Bastos1?Luis A. P. Freitas1Email:lapdfrei@usp.br
[1] Faculdade de Ci�ncias Farmac�uticas de Ribeiro Preto, Universidade de So Paulo, Via do Caf� s/n, 14040-903 Ribeiro Preto, So Paulo, Brazil

Fast-disintegrating sublingual tablets: Effect of epinephrine load on tablet characteristics

admin — Mon, 02 Feb 2009 12:47:30 +0000

The aim of this study was to evaluate the effect of increasing epinephrine load on the characteristics of fast-disintegrating sublingual tablets for the potential emergency treatment of anaphylaxis. Four tablet formulations, A, B, C,; D, containing 0%, 6%, 12%,; 24% of epinephrine bitartrate, respectively,; microcrystalline cellulose:low-substituted hydroxypropyl cellulose (9?1), were prepared by direct compression, at a range of compression forces. Tablet weight variation, content uniformity, hardness, disintegration time, wetting time,; friability were measured for each formulation at each compression force. All 4 tablet formulations at each compression force were within the United States Pharmacopeia (USP) limits for weight variation; content uniformity. A linear increase in compression force resulted in an exponential increase in hardness for all formulations, a linear increase in disintegration; wetting times of A,; an exponential increase in disintegration; wetting times of B, C,; D. At a mean�SD hardness of ?2.3�0.2 kg, all tablet formulations passed the USP friability test. At a mean�SD hardness of ?3.1�0.2 kg, all tablet formulations resulted in disintegration; wetting times of >10 seconds; >30 seconds, respectively. Tablets with drug loads from 0% to 24% epinephrine can be formulated with hardness, disintegration times,; wetting times suitable for sublingual administration.

Mutasem M. Rawas-Qalaji1?F. Estelle2?R. Simons2?Keith J. Simons3Email:simons@ms.umanitoba.ca
[1] Faculty of Pharmacy, University of Manitoba, Winnipeg, Manitoba, Canada ;[2] Section of Allergy; Clinical Immunology, Department of Pediatrics; Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada ;[3] Faculty of Pharmacy, Department of Pediatrics; Child Health, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada

Ferroelastic domain switching fatigue in lead zirconate titanate ceramics

admin — Wed, 17 Sep 2008 04:02:25 +0000

The influence of the frequency and amplitude of cyclic mechanical loading on soft, tetragonal lead zirconate titanate (PZT) ceramics was investigated via neutron diffraction. Intensity change in the {2 0 0} reflections provided quantitative measurements of domain switching behavior, domain texture and the strain resulting from domain switching. The results are explained using a viscoelasticity model. It was found that the magnitude of applied stress affects the level of strain accumulated, while its frequency affects the time taken for the strain to reach saturation. Furthermore, markedly different behaviors are exhibited by poled and unpoled samples. For samples loaded under identical conditions, the frequency effect is more pronounced in unpoled samples and the accumulated ferroelastic strain is greater in poled samples.

Soodkhet Pojprapai ImlaoEmail:soodkhet@student.unsw.edu.au?Jacob L. Jonesb?Andrew J. Studerc?Jennifer Russella?Nagarajan Valanoora?Mark Hoffmana
[a]School of Materials Science; Engineering, University of New South Wales, Sydney, NSW 2052, Australia;[b]Department of Materials Science; Engineering, University of Florida, Gainesville, FL, USA;[c]Bragg Institute, Australian Nuclear Science; Technology Organisation, Sydney, NSW, Australia

Finite element simulation of quench distortion in a low-alloy steel incorporating transformation kinetics

admin — Wed, 17 Sep 2008 03:56:37 +0000

The uncontrolled distortion of steel parts has been a long-standing and serious problem for heat treatment processes, especially quenching. To get a better understanding of distortion, the relationship between transformation kinetics and associated distortion has been investigated using a low-alloy chromium steel. Because martensite is a major phase transformed during the quenching of steel parts and is influential in the distortion, a new martensite start (Ms) temperature and a martensite kinetics equation are proposed. Oil quenching experiments with an asymmetrically cut cylinder were conducted to confirm the effect of phase transformations on distortion. ABAQUS and its user-defined subroutines UMAT and UMATHT were used for finite element method (FEM) analysis. The predictions of the FEM simulation compare well with the measured data. The simulation results allow for a clear understanding of the relationship between the transformation kinetics and distortion.

Seok-Jae Leea?Young-Kook Leeb Email:yklee@yonsei.ac.kr
[a]Research Institute of Iron; Steel Technology, Yonsei University, Seoul 120-749, Republic of Korea;[b]Department of Metallurgical Engineering, Yonsei University, Seoul 120-749, Republic of Korea

Features of feathery ? structure in a near-? TiAl alloy

admin — Wed, 17 Sep 2008 02:21:58 +0000

This work characterizes the feathery-like structures produced in a Ti�46.8Al�1.7Cr�1.8Nb (at.%) alloy during rapid continuous cooling from the domain. Their morphology and crystallography are described using different microscopy and orientation mapping techniques. These feathery-like structures are divided into many small domains, characterized by low-angle misorientations (rotated less than 15�) between the domains. The domains comprise multiple parallel ? lamellae and rare traces of 2. These lamellae follow the Blackburn orientation relationship and have a {1 1 1}? habit plane. Two types of ?-feathery structures were identified according to their location and crystallography. The grain-boundary ?-feathery structures originate from lamellar structures that grow into a neighboring grain. Alternatively, the internal ?-feathery structures are located in the interior of prior grains and show an average misorientation of 36� around one axis of the lamellar structure in which it is embedded. This paper describes these two ?-feathery structures in detail and discusses their development in light of the mechanisms available in the literature, particularly sympathetic nucleation.

S.R. Dey1?E. Bouzya?A. Hazotte aEmail:alain.hazotte@univ-metz.fr
[a]Laboratoire d�Etude des Textures et Application aux Mat�riaux, UMR CNRS/UPVM 7078, Ile du Saulcy, 57045 Metz Cedex 1, France

Fault zone deformation controlled by carbonate mechanical stratigraphy, Balcones fault system, Texas

admin — Wed, 17 Sep 2008 01:24:20 +0000

Normal faults in Cretaceous carbonates in the Balcones fault system provide important analogs for fault zone architecture and deformation in carbonate reservoirs worldwide. Mechanical layering is a fundamental control on carbonate fault zones. Relatively planar faults with low-displacement gradients develop in massive, strong, clay-poor limestones and dolomites. In less competent clay-rich strata, shale beds impede fault propagation, resulting in fault-related folding, and locally steep bedding dips. Faults in clay-poor massive limestones and dolomites tend to be steep (70� or more), whereas weaker, clay-rich limestones develop faults with shallower dips (60� or less). Fault zone rocks show evidence of cataclasis, cementation, deformation of cement by mechanical twinning and pressure solution, and multiple generations of cement with differing degrees of deformation, indicating contemporaneous cementation and fault slip. In stratigraphic sequences consisting of both competent and incompetent strata, the ratio of incompetent to competent strata by thickness is a useful guide for inferring the relative rates of fault displacement and propagation. Low displacement-to-propagation ratios associated with competent strata generate low-displacement gradients, inhibiting fault-related folding. Conversely, high displacement-to-propagation ratios associated with incompetent strata promote high-displacement gradients and fault-related folding.

David A. Ferrill?Alan P. Morris
Geosciences and Engineering Division, Department of Earth, Material, and Planetary Sciences, Southwest Research Institute~R, 6220 Culebra Road, San Antonio, Texas 78238

Fades architecture of a net transgressive sandstone reservoir analog: The Cretaceous Hosta Tongue, New Mexico

admin — Wed, 17 Sep 2008 01:21:57 +0000

Net transgressive sandstones form a significant component of many shallow-marine reservoirs, but their shale-poor character commonly masks complex facies architecture and stratigraphy associated with significant permeability variations that impact reservoir drainage patterns and ultimate recovery. In this article, the controls on net transgressive sandstone reservoir architecture are investigated through a detailed analysis of the Cretaceous Hosta Tongue of the Point Lookout Sandstone (informally termed Hosta sandstone in this article] outcrop in New Mexico. Mapping of facies architecture within a series of adjacent canyons has enabled a quantitative three-dimensional reconstruction of key stratigraphic surfaces and sand body distributions from an updip pinch-out to a downdip pinch-out of the net transgressive sandstone complex. The Hosta sandstone contains a complex arrangement of wave-and tide-dominated facies associations arranged in an overall transgressive pattern. Tidal channel-fill sandstones, tidal sheet-form sandstones, and heterolithic tidal-flat and lagoonal deposits comprise the stratigraphy in the updip part of the system. These deposits pass abruptly downdip into wave-dominated shoreface sandstones. The facies composition indicates that the Hosta sandstone represents a wave-dominated barrier shoreline and a tide-dominated back-barrier lagoon. Facies associations are partitioned both vertically and laterally by a hierarchy of transgressive erosion (ravinement) surfaces cut by wave and tidal processes. Reconstructing the geomorphol-ogy and spatial organization of these surfaces is critical to understanding sand body distribution and facies architecture at high-resolution (intrareservoir) scale.

Peter J. Sixsmith?Gary J. Hampson?Sanjeev Gupta
Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom

FROM START TO FINISH

admin — Wed, 17 Sep 2008 00:17:37 +0000

The author of our popular “Litigation” column explains how to win over jurors in opening and closing statements. Find out why you shouldn’t talk like a lawyer, how you can deal with implausible facts, and more.

James W. McElhaney

Fair value; the IASB/FASB conceptual framework project: An alternative view

admin — Tue, 16 Sep 2008 23:16:56 +0000

This paper analyses various controversial issues arising from the current project of the IASB; FASB to develop a joint conceptual framework for financial reporting standards. It discusses their possible implications for measurement;, in particular, for the use of fair value as the preferred measurement basis. Two competing world views are identified as underlying the debate: a Fair Value View, implicit in the IASB’s public pronouncements,; an Alternative View implicit in publicly expressed criticisms of the IASB’s pronouncements. The Fair Value View assumes that markets are relatively perfect; complete; that, in such a setting, financial reports should meet the needs of passive investors; creditors by reporting fair values derived from current market prices. The Alternative View assumes that markets are relatively imperfect; incomplete; that, in such a market setting, financial reports should also meet the monitoring requirements of current shareholders (stewardship) by reporting past transactions; events using entity-specific measurements that reflect the opportunities actually available to the reporting entity. The different implications of the two views are illustrated by reference to specific issues in recent accounting standards. Finally, the theoretical support for the two views is discussed. It is concluded that, in a realistic market setting, the search for a universal measurement method may be fruitless; a more appropriate approach to the measurement problem might be to define a clear measurement objective; to select the measurement method that best meets that objective in the particular circumstances that exist in relation to each item in the accounts. An example of such an approach is deprival value, which is not, at present, under consideration by the IASB. 2008 Accounting Foundation, The University of Sydney.

Whittington, G.Email:gw12@cam.ac.uk
Department of Financial Accounting, Centre for Financial Analysis; Policy, University of Cambridge

Facing Mount Kenya or Facing Mecca? The Mungiki, ethnic violence and the politics of the Moi succession in Kenya, 1987–2002

admin — Sun, 22 Jun 2008 23:29:05 +0000

Kenya’s return to pluralist politics in the early 1990s saw the eruption of political violence that has since laid siege to human rights and democracy. This article discusses the Mungiki movement which, like the Mau Mau movement that waged armed struggle against the British in the 1950s, has sprouted among the Kikuyu. It examines Mungiki within the broader theoretical context of competitive electoral politics and political violence in contemporary Kenya. In addition to tracing the movement’s religious and ideological roots, the article shows how ‘informal repression’ or quasi-legitimization of sectarian violence for political ends by the state, has transformed a ‘moral ethnic’ movement into a ‘politically tribal’ one. As a contribution to the academic debate on Mungiki, the article draws on the rich public debate in Kenya and the author’s close study of the movement in 2001–2.

Peter Mwangi Kagwanja