bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of the Thromboxane A2 Receptor in the Regulation of Steroidogenic Acute Regulatory Gene Expression in Murine Leydig Cells
Authors: Pandey Akhilesh K. , Yin Xiangling , Schiffer Randolph B. , Hutson James C. , Stocco Douglas M. , Grammas Paula , Wang XingJia
Published: March 2009

Recent studies suggested an involvement of thromboxane A2 in cyclooxygenase-2-dependent inhibition of steroidogenic acute regulatory (StAR) gene expression. The present study further investigated the role of thromboxane A2 receptor in StAR gene expression and steroidogenesis in testicular Leydig cells. The thromboxane A2 receptor was detected in several Leydig cell lines. Blocking thromboxane A2 binding to the receptor using specific antagonist SQ29548 or BM567 resulted in dose-dependent increases in StAR protein and steroid production in MA-10 mouse Leydig cells. The results were confirmed with Leydig cells isolated from rats. StAR promoter activity and StAR mRNA level in the cells were also increased after the treatments, suggesting an involvement of the thromboxane A2 receptor in StAR gene transcription. Furthermore study indicated that blocking the thromboxane A2 receptor reduced dosage sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 protein, a transcriptional repressor of StAR gene expression. Specific binding of the antagonists to the receptors on cellular membrane was demonstrated by binding assays using 3H-SQ29548 and binding competition between 3H-SQ29548 and BM567. Whereas SQ29548 enhanced cAMP-induced StAR gene expression, in the absence of cAMP, it was unable to increase StAR protein and steroidogenesis. However, when the receptor was blocked by the antagonist, subthreshold levels of cAMP were able to induce maximal levels of StAR protein expression, suggesting that blocking the thromboxane A2 receptor increase sensitivity of MA-10 cells to cAMP stimulation. Taken together, the results from the present and previous studies suggest an autocrine loop, involving cyclooxygenase-2, thromboxane A synthase, and thromboxane A2 and its receptor, in cyclooxygenase-2-dependent inhibition of StAR gene expression.
The Antiobesity Effects of Centrally Administered Neuromedin U and Neuromedin S Are Mediated Predominantly by the Neuromedin U Receptor 2 (NMUR2)
Authors: Peier Andrea , Kosinski Jennifer , Cox-York Kimberly , Qian Ying , Desai Kunal , Feng Yue , Trivedi Prashant , Hastings Nicholas , Marsh Donald J.
Published: March 2009

Neuromedin U (NMU) and neuromedin S (NMS) are structurally related neuropeptides that have been reported to modulate energy homeostasis. Pharmacological data have shown that NMU and NMS inhibit food intake when administered centrally and that NMU increases energy expenditure. Additionally, NMU-deficient mice develop obesity, whereas transgenic mice overexpressing NMU are lean and hypophagic. Two high-affinity NMU/NMS receptors, NMUR1 and NMUR2, have been identified. NMUR1 is predominantly expressed in the periphery, whereas NMUR2 is predominantly expressed in the brain, suggesting that the effects of centrally administered NMU and NMS are mediated by NMUR2. To evaluate the role of NMUR2 in the regulation of energy homeostasis, we characterized NMUR2-deficient (Nmur2−/−) mice. Nmur2−/− mice exhibited a modest resistance to diet-induced obesity that was at least in part due to reduced food intake. Acute central administration of NMU and NMS reduced food intake in wild-type but not in Nmur2−/− mice. The effects on activity and core temperature induced by centrally administered NMU were also absent in Nmur2−/− mice. Moreover, chronic central administration of NMU and NMS evoked significant reductions in body weight and sustained reductions in food intake in mice. In contrast, Nmur2−/− mice were largely resistant to these effects. Collectively, these data demonstrate that the anorectic and weight-reducing actions of centrally administered NMU and NMS are mediated predominantly by NMUR2, suggesting that NMUR2-selective agonists may be useful for the treatment of obesity.
Design of radial impellers: A combined extended analytical and numerical method
Authors: Epple P , Karic B , Ilić Č , Becker S , Durst F , Delgado A
Published: March 2009

The use of high-speed radial impellers is very common in blowers for industrial application. It is also very common to manufacture these impellers using circular arc blades. The design process as well is almost always based on former impeller series and experimental data available. In this work, a method is presented to improve the efficiency of radial impellers with a combined analytical and numerical method. This method is based on an extended analytical formulation of the flow in radial impellers, allowing optimizing efficiency in the design stage. It is complemented by the mathematical implementation of a well-known qualitative principle of efficiency optimization according to Carnot. Finally, the torque-speed characteristic of the motor is included in the design stage. The blade shapes are computed using an inverse method. The design is then validated by means of computational fluid dynamics (CFD) computation with a commercial solver. Finally, a prototype was built and measurements were carried out in a test rig. It is also shown that the design method provided very good predictions leading to an efficiency increase of 13 per cent and a maximum flowrate increase of 11 per cent. The design point was also met. It is also shown that the numerical computations and measurements are in good agreement. An analysis of the CFD results is also presented, giving an insight view into the substantial flow information within the old and the new impellers. The method presented is a combined analytical and numerical method suited to design high-efficiency radial impellers considering also the torque-speed characteristic of the motor without the need of a previous impeller series or knowledge of experimental data.
Analysis of pitch plane railway vehicle—track interactions due to single and multiple wheel flats
Authors: Uzzal R U A , Ahmed A K W , Rakheja S
Published: March 2009

The dynamic impact forces caused by wheel defects such as a flat have been of primary concern for freight trains operating at high speeds. A pitch plane model of a railway vehicle coupled with a comprehensive three-layer track system model is developed to study impact forces generated at the wheel—rail (W—R) interface in the presence of wheel flats. The W—R interaction is described by the non-linear Hertzian contact spring, while the rail is represented by a continuous Euler beam. The Rayleigh—Ritz method is used to solve the coupled partial and ordinary differential equations of the vehicle—track system. An idealized haversine wheel flat with the rounded corner is included in the W—R contact model. The W—R interface forces are evaluated under single or multiple flats on a single as well as multiple wheels. The forces transmitted to the bearings, pads, and the ballast are also evaluated under impacts due to single as well as multiple wheel flats. The results obtained through parametric analyses are discussed in view of a desirable design and operating condition to reduce the magnitude of impact loads. The results suggest that the rail mass, rail pad stiffness and damping, bending stiffness of rail, and ballast mass affect the W—R impact force considerably, apart from the flat size and vehicle speed. The influence of phase between the multiple flats on the resulting magnitudes of impact forces is also evaluated. The results suggest that the impact loads due to two flats are comparable with those due to a single flat when the spacing between the two flats exceeds 45°. Furthermore, the magnitude of impact force due to a single wheel flat could be greater than that due to in-phase flats on both wheels, which can be attributed to the pitch dynamics of the bogie.
Quantification of Urinary Albumin by Using Protein Cleavage and LC-MS/MS
Authors: Seegmiller Jesse C , Barnidge David R , Burns Bradley E , Larson Timothy S , Lieske John C , Kumar Rajiv
Published: March 2009

Background: Urinary albumin excretion is a sensitive diagnostic and prognostic marker for renal disease. Therefore, measurement of urinary albumin must be accurate and precise. We have developed a method to quantify intact urinary albumin with a low limit of quantification (LOQ).

Methods: We constructed an external calibration curve using purified human serum albumin (HSA) added to a charcoal-stripped urine matrix. We then added an internal standard, 15N-labeled recombinant HSA (15NrHSA), to the calibrators, controls, and patient urine samples. The samples were reduced, alkylated, and digested with trypsin. The concentration of albumin in each sample was determined by liquid chromatography–tandem mass spectrometry (LC-MS/MS) and linear regression analysis, in which the relative abundance area ratio of the tryptic peptides 42LVNEVTEFAK51 and 526QTALVELVK534 from albumin and 15NrHSA were referenced to the calibration curve.

Results: The lower limit of quantification was 3.13 mg/L, and the linear dynamic range was 3.13–200 mg/L. Replicate digests from low, medium, and high controls (n = 5) gave intraassay imprecision CVs of 2.8%–11.0% for the peptide 42LVNEVTEFAK51, and 1.9%–12.3% for the 526QTALVELVK534 peptide. Interassay imprecision of the controls for a period of 10 consecutive days (n = 10) yielded CVs of 1.5%–14.8% for the 42LVNEVTEFAK51 peptide, and 6.4%–14.1% for the 526QTALVELVK534 peptide. For the 42LVNEVTEFAK51 peptide, a method comparison between LC-MS/MS and an immunoturbidometric method for 138 patient samples gave an R2 value of 0.97 and a regression line of y = 0.99x + 23.16.

Conclusions: Urinary albumin can be quantified by a protein cleavage LC-MS/MS method using a 15NrHSA internal standard. This method provides improved analytical performance in the clinically relevant range compared to a commercially available immunoturbidometric assay.
New Dual Monoclonal ELISA for Measuring Plasma Osteopontin as a Biomarker Associated with Survival in Prostate Cancer: Clinical Validation and Comparison of Multiple ELISAs
Authors: Anborgh Pieter H , Wilson Sylvia M , Tuck Alan B , Winquist Eric , Schmidt Nancy , Hart Russell , Kon Shigeyuki , Maeda Masahiro , Uede Toshimitsu , Stitt Larry W , Chambers Ann F
Published: March 2009

Background: A previously developed monoclonal/polyclonal ELISA (Mono/Poly) to detect plasma concentrations of osteopontin (OPN) was shown to provide prognostic information in breast, prostate, and other cancers. Here we describe the clinical validation of a new dual monoclonal (Dual Mono) assay. We compared both assays with 4 assays that recognize defined regions of OPN protein (dual polyclonal systems 5-1, 4-1, 4-3 and polyclonal-monoclonal system 1-3).

Methods: OPN sequences recognized by the monoclonal antibodies that make up the Dual Mono ELISA were identified by Pepscan CLIPS™ analysis. Using the 6 ELISAs, we measured OPN in plasma from 66 patients with castration-resistant prostate cancer, and we assessed the ability of each assay to predict patient survival.

Results: The assays varied in measured plasma OPN concentrations, with median values ranging from 112 to 1740 μg/L, and ability to predict patient survival. By Cox univariable regression of survival by tertiles of OPN, the Mono/Poly and Dual Mono ELISAs had the highest log-rank χ2 values. After adjustment for risk factors independently associated with survival in our samples, OPN remained associated with survival only for the Mono/Poly and Dual Mono systems.

Conclusions: OPN plasma values varied significantly depending on the assay used. Only the Mono/Poly and Dual Mono systems were independently associated with survival in a population of men with castration-resistant prostate cancer. The availability of a clinically validated, dual monoclonal–based ELISA will provide consistent reagents for studies of OPN plasma concentrations in cancer and other pathologies.
An analysis of knowledge base maintenance
Authors: Debenham John
Published: March 2009

Knowledge base maintenance is managed by constructing a formal model. In this model the representation of each chunk of know ledge encapsulates the knowledge in a set of declarative rules, each of which in turn encapsulates the knowledge in a set of imperative programs. In this model an "item" is the unit of knowledge representation. Items are at a higher level of abstraction than rules. Understanding what has to be done to maintain the integrity of an item leads to a specification of the modifications to the set of programs that implement it. An analysis of the maintenance of the formal model is achieved by introducing maintenance links. Analysis of the maintenance links shows that they are of four different types. The density of the maintenance links is reduced by transforming that set into an equivalent set. In this way the knowledge base maintenance problem is analyzed and simplified. A side benefit of knowledge items as a formalism is that they contain knowledge constraints that protect the knowledge from unforeseen modification.
Semantic web technologies for enterprise application integration
Authors: Anicic Nenad , Ivezic Nenad
Published: March 2009

Large industrial interoperability projects use syntax-based Enterprise Application Integration standards, such as XML Schema, to accomplish interoperable data exchange among enterprise applications. In this paper, we describe an approach to assess the potential impact of Semantic Web technologies on these standards and on testability of integration results when using these standards. The experimental approach includes an automated translation of an XML Schema-based representation of business document content models into an OWL-based ontology. Based on this ontology, we use the Semantic Web representation and reasoning mechanisms to validate ontological constructs and constraints in support of data exchange. We demonstrate novel model-based integration capabilities that go beyond the existing syntax-based approaches. These new capabilities are relevant when managing multiple enterprise ontologies derived from a common ontology.
The collaborative development of didactic materials
Authors: Padron Carmen , Dodero Juanma , Diaz Paloma , Aedo Ignacio
Published: March 2009

In this paper we present an analysis of the development process of technology-supported didactic material. Such analysis considers didactic materials as the conjunction of contents and instructional design used to guide learning and teaching processes. And we examine why several features such as reusability, semantic interoperability and collaboration support must be ensured from the earlier stages of the material creation process. For those reasons didactic material development is not a trivial task and demands of a development methodology support and a high-quality authoring environment. We describe how the MD2 research project provides an integrated solution for creation of didactic materials that take into account those rationales. The MD2 solution is based on two approaches first, the definition of a method for the collaborative creation of didactic materials and second, the elaboration of a quality evaluation framework for a priori testing of educational products. We also present CASLO a collaborative authoring tool used to facilitate these endeavors.
Constraint-based knowledge representation for individualized instruction
Authors: Stellan Ohlsson , Mitrovic Antonija
Published: March 2009

Traditional knowledge representations were developed to encode complete explicit and executable programs, a goal that makes them less than ideal for representing the incomplete and partial knowledge of a student. In this paper, we discuss state constraints, a type of knowledge unit originally invented to explain how people can detect and correct their own errors. Constraint-based student modeling has been implemented in several intelligent tutoring systems (ITS) so far, and the empirical data verifies that students learn while interacting with these systems. Furthermore, learning curves are smooth when plotted in terms of individual constraints, supporting the psychological appropriateness of the representation. We discuss the differences between constraints and other representational formats, the advantages of constraint-based models and the types of domains in which they are likely to be useful.
Adapting the unified software development process for user interface development
Authors: Obrenovic Zeljko , Starcevic Dusan
Published: March 2009

In this paper we describe how existing software developing processes, such as Rational Unified Process, can be adapted in order to allow disciplined and more efficient development of user interfaces. The main objective of this paper is to demonstrate that standard modeling environments, based on the UML, can be adapted and efficiently used for user interfaces development. We have integrated the HCI knowledge into developing processes by semantically enriching the models created in each of the process activities of the process. By using UML, we can make easier use of HCI knowledge for ordinary software engineers who, usually, are not familiar with results of HCI researches, so these results can have broader and more practical effects. By providing a standard means for representing human computer interaction, we can seamlessly transfer UML models of multimodal interfaces between design and specialized analysis tools. Standardization provides a significant driving force for further progress because it codifies best practices enables and encourages reuse, and facilitates inter working between complementary tools. Proposed solutions can be valuable for software developers, who can improve quality of user interfaces and their communication with user interface designers, as well as for human computer interaction researchers, who can use standard methods to include their results into software developing processes.
Evaluation and comparison of search engines using the LSP method
Authors: Dujmovic Jozo , Bai Haishi
Published: March 2009

We present a comprehensive model for quantitative evaluation and comparison of search engines. The model is based on the LSP method for system evaluation. The basic contribution of our approach is the aggregation of all relevant attributes that reflect functionality, usability, and performance of search engines. In this respect our model is fully consistent with the ISO 9126 standard for software product evaluation. Performance analysis of competitive search engines is based on our search engine benchmarking tool (SEben) that is also described in the paper.
A comparison of the bagging and the boosting methods using the decision trees classifiers
Authors: Machova Kristina , Puszta Miroslav , Barcak Frantisek , Bednar Peter
Published: March 2009

In this paper we present an improvement of the precision of classification algorithm results. Two various approaches are known: bagging and boosting. This paper describes a set of experiments with bagging and boosting methods. Our use of these methods aims at classification algorithms generating decision trees. Results of performance tests focused on the use of the bagging and boosting methods in connection with binary decision trees are presented. The minimum number of decision trees, which enables an improvement of the classification performed by the bagging and boosting methods, was found. The tests were carried out using the Reuter?s 21578 collection of documents as well as documents from an Internet portal of TV broadcasting company Mark?za. The comparison of our results on testing the bagging and boosting algorithms is presented.
Data mining techniques based on grey system theories for time sequence data
Authors: Bin Liu , Hui Zhang , Sifeng Liu , Yaoguo Dang
Published: March 2009

Data mining is an interesting focus in computer science field now This paper deals with data mining techniques based on Grey system theories for time sequence data. Firstly, thoughts of data mining with embedded knowledge are expatiated, and the status quo of Data mining techniques is presented briefly. Then, based on the above thoughts and the Grey system theories, data mining techniques based on Grey system theories for time sequence data are proposed for the first time, and the idiographic arithmetic with GM(1,1) as an example is introduced in this paper. Last, it forecasts the total homes in 2002~2005 connecting with Internet in Shang Hai City by the arithmetic.
A simple implementation of grammar libraries
Authors: Cervelle Julien , Forax Rémi , Roussel Gilles
Published: March 2009

This paper presents an extension of the Tatoo compiler compiler that supports separate compilation and dynamic linking of formal grammars. It allows the developer to define reusable libraries of grammars such as those of arithmetic expressions or of classical control operators. The aim of this feature is to simplify the development of domain specific languages especially for non specialists in grammar writing.
Prototype environment for controller programming in the IEC 61131-3 ST language
Authors: Rzoñca Dariusz , Sadolewski Jan , Trybus Bartosz
Published: March 2009

A prototype compiler of the ST language (Structured Text), its operation and internal structure is presented. The compiler is a principal part of CPDev engineering environment for programming industrial controllers according to IEC 61131-3 standard. The CPDev is under development at Rzesz?w University of Technology. The compiler generates an universal executable code as final result. The code can be interpreted on different platforms by target-specific virtual machines. Sample platforms include AVR, ARM, MCS-51, PC.
Interfacing the system evaluation method LSP with E-commerce web sites
Authors: Buckley Greydon , Dujmovic Jozo
Published: March 2009

For many people faced with a tough purchasing decision, the research tool of choice is a web browser. Search engines solve the general problem of finding relevant data, however it is up to the user to sort, filter, and evaluate it. Decision support methods such as LSP can turn raw data into formal evaluations, but they are generally disconnected from the Web - the most up-to-date, widely-used, and convenient source of data available. This paper demonstrates how LSP can be connected to the Web, so that live data from e-commerce web sites can be used in consumer-oriented system evaluations.
Modeling of login procedure for wireless application with interaction overview diagrams
Authors: Plavsic Vera , Secerov Emil
Published: March 2009

In this paper we describe in details UML modeling of login procedure, which is a part of UserBarCodeReader application, developed for large stores and intended for use as a customer support during the shopping session. Login procedure is realized within access control system, in this case over a wireless network. Paper gives the whole modeling and implementation cycle of login procedure, from Use Case diagrams to the Java source code. Login procedure is modeled using interaction overview diagram, new in UML 2.0 which gives concise representation and divides complex sequence diagram into several smaller. The link between these diagrams is modeled with OCL postcondition and precondition expressions.
Wireless sensor network application programming and simulation system
Authors: Zivanov Zarko , Rakic Predrag , Hajdukovic Miroslav
Published: March 2009

We present, a wireless sensor network application programming and simulation system, suitable for wireless sensor network application development for both resource constrained and unconstrained hardware. Developed programs can be tested inside simulator, or (with source unchanged) executed directly on hardware. Main contribution of our project is uniform object oriented programming model with predefined basic concurrency abstractions.
Representing and querying multiple ontologies with Contextual Logic Programming
Authors: Lopes Nuno , Fernandes Cláudio , Abreu Salvador
Published: March 2009

The system presented in this paper uses Contextual Logic Programming as a computational hub for representing and reasoning over knowledge modeled by web ontologies, integrating the approach with similar mechanisms which we already developed. As a result of its Logic Programming heritage, the system may also recursively interrogate other ontologies or data repositories, providing a semantic integration of multiple sources. The components required to behave as a SPARQL query engine are explained and examples of integration of deferent sources are shown - in particular, the case of multiple OWL ontologies is discussed. .
Component J: A component-based programming language with dynamic reconfiguration
Authors: Seco João , Silva Ricardo , Piriquito Margarida
Published: March 2009

This paper describes an evolution of the ComponentJ programming language, a component-based Java-like programming language where composition is the chosen structuring mechanism. ComponentJ constructs allow for the high-level specification of component structures, which are the basis for the definition of compound objects. In this paper we present a new language design for ComponentJ which is more flexible and also allows the dynamic reconfiguration of objects. The manipulation of components and composition operations at the programming language level allows for the compile time verification, by a type system, of safety structural properties of ComponentJ programs. This work is based on earlier fundamental results where the main concepts are presented and justified in the form of a core component calculus. .
Developing libraries using software transactional memory
Authors: Dias Ricardo , Lourenço João , Cunha Gonçalo
Published: March 2009

Software transactional memory is a promising programming model that adapts many concepts borrowed from the databases world to control concurrent accesses to main memory (RAM). This paper discusses how to support revertible operations, such as memory allocation and release, within software libraries that will be used in software memory transactional contexts. The proposal is based in the extension of the transaction life cycle state diagram with new states associated to the execution of user-defined handlers. The proposed approach is evaluated in terms of functionality and performance by way of a use case study and performance tests. Results demonstrate that the proposal and its current implementation are flexible, generic and efficient. .
Inactivation of GSK-3β by Metallothionein Prevents Diabetes-Related Changes in Cardiac Energy Metabolism, Inflammation, Nitrosative Damage, and Remodeling
Authors: Wang Yuehui , Feng Wenke , Xue Wanli , Tan Yi , Hein David W. , Li Xiao-Kun , Cai Lu
Published: March 2009

OBJECTIVE

Glycogen synthase kinase (GSK)-3β plays an important role in cardiomyopathies. Cardiac-specific metallothionein-overexpressing transgenic (MT-TG) mice were highly resistant to diabetes-induced cardiomyopathy. Therefore, we investigated whether metallothionein cardiac protection against diabetes is mediated by inactivation of GSK-3β.

RESEARCH DESIGN AND METHODS

Diabetes was induced with streptozotocin in both MT-TG and wild-type mice. Changes of energy metabolism–related molecules, lipid accumulation, inflammation, nitrosative damage, and fibrotic remodeling were examined in the hearts of diabetic mice 2 weeks, 2 months, and 5 months after the onset of diabetes with Western blotting, RT-PCR, and immunohistochemical assays.

RESULTS

Activation (dephosphorylation) of GSK-3β was evidenced in the hearts of wild-type diabetic mice but not MT-TG diabetic mice. Correspondingly, cardiac glycogen synthase phosphorylation, hexokinase II, PPARα, and PGC-1α expression, which mediate glucose and lipid metabolisms, were significantly changed along with cardiac lipid accumulation, inflammation (TNF-α, plasminogen activator inhibitor 1 [PAI-1], and intracellular adhesion molecule 1 [ICAM-1]), nitrosative damage (3-nitrotyrosin accumulation), and fibrosis in the wild-type diabetic mice. The above pathological changes were completely prevented either by cardiac metallothionein in the MT-TG diabetic mice or by inhibition of GSK-3β activity in the wild-type diabetic mice with a GSK-3β–specific inhibitor.

CONCLUSIONS

These results suggest that activation of GSK-3β plays a critical role in diabetes-related changes in cardiac energy metabolism, inflammation, nitrosative damage, and remodeling. Metallothionein inactivation of GSK-3β plays a critical role in preventing diabetic cardiomyopathy.
Pressure drop and hydrodynamic properties of pulses in two‐phase gas‐liquid downflow through packed columns
Authors: Rao V. Govardhana , Drinkenburg A. A. H.
Published: March 2009

The hydrodynamics and the pulse properties in the pulse flow regime of gas‐liquid downflow through a packed column were studied using 6 mm Raschig rings and 3 mm spheres as packings. The pulse flow regime is considered to be gas‐continuous flow outside the pulses and more like dispersed bubble flow inside the pulses and the pressure drop is viewed as being contributed to by the gas continuous part outside the pulses and by the pulses themselves. Correlations for the total pressure drop, the pressure drop across the pulse and for the pulse velocity are obtained. The experimental data of the average holdup, the pulse holdup, the base holdup and the transition from gas continuous to pulse flow regime are compared with the literature values.
An experimental study of spouting in large sector beds
Authors: Green M. C. , Bridgwater J.
Published: March 2009

In a sector spouted bed, fluid is introduced into the bottom at the junction of two vertical walls, the bed forming a sector in horizontal cross‐section. The hydrodynamics of beds of 30° sector angle have been studied in equipment of radius up to 0.78 m. The spout radius is greater than would be predicted from standard correlations on small circular beds. The overall pressure drop can be less than 20% of that found for minimum fluidisation. The vertical pressure distribution is given approximately by a quarter cosine function. Minimum spouting velocity decreases with increasing size of bed, loss of spouting being caused by a decrease in fountain height followed by snuffing of the spout by annular solids.
Particle segregation in a spouted bed of binary mixtures of particles
Authors: Uemaki O. , Yamada R. , Kugo M.
Published: March 2009

Minimum spouting velocity and segregation behaviour of binary mixtures of particles differing in size have been studied. The experiments were carried out in a bed of 20 cm diameter at superficial gas velocities up to 1.3 Ums by use of silica sand of four different particle sizes from 0.655 to 2.23 mm.

An empirical equation was proposed for the minimum spouting velocity of binary mixtures. The effects of the particle size difference and the superficial gas velocity on segregation were investigated. Results showed that considerable radial segregation as well as axial segregation occurred even for high gas velocity under the condition of large particle size difference.
Behaviour of a conical spouted‐bed dryer for animal blood
Authors: Pham Q. T.
Published: March 2009

A 60° conical bed of inert particles spouted with hot air has been used as a medium for drying animal blood into a powder with little thermal degradation. The spouting and drying performances of the dryer were investigated. A feature of considerable practical significance is the existence of an initial regime of incomplete spouting in which the solids in the annulus are partly held stagnant by friction, causing a reduced pressure drop. A model of the drying process was developed to predict the variations in maximum throughput and product properties with changes in operating conditions. Good agreement between predictions and experimental results was found.
Jet penetration measurements in a venturi scrubber
Authors: Viswanathan S. , St. Pierre C. C. , Gnyp A. W.
Published: March 2009

The maximum centreline penetrations, l**, of cross‐current liquid jets in a Venturi scrubber were measured for orifice diameters, d, of 1.397, 2.108, 2.565 and 3.860 mm. The data are correlated by

for the range of conditions, 36 ≤ gas throat velocity Vg ≤ 125 m/s; 1.2 ≤ liquid injection velocity Vj ≤ 18 m/s;

0.06 ≤ liquid to gas ratio
Liquid dispersion in static in‐line mixers
Authors: Taweel A. M. Al , Walker L. D.
Published: March 2009

Liquid/liquid dispersion in static mixers has been investigated using Lightnin “In‐liner” mixing elements. The average drop size was found to decrease with increasing residence time, gradually approaching an equilibrium size whose magnitude agrees reasonably well with Kolmogoroff's theory for drop rupture in turbulent flows.

The efficiency at which mechanical energy is utilized in the generation of new interfacial area was evaluated as a function of design and operating conditions and was found to be highest when the final drop size is much larger than the achievable equilibrium value.
Stripping of HCN in a packed tower
Authors: Avedesian Michael M. , Spira Paul , Kanduth Harald
Published: March 2009

Experiments were carried out to measure the Henry's law constant for HCN in solutions from the cyanidation of zinc concentrate. The measured value for zinc thickener underflow solution was 5.0 atm/mole fraction whereas for synthetic leach solutions and pure cyanide solutions it was 6.1 and 6.4, respectively. Pilot plant stripping tests were carried out using a 0.3 m diameter column operated under full‐scale hydrodynamic conditions to measure the mass transfer coefficient and also to study the potential scaling problem due to the precipitation of gypsum and CuCNS. These data were used to design the full‐scale plant in a silver recovery flowsheet.
A novel direct‐contact condensation pattern of vapour bubbles in an immiscible liquid
Authors: Higeta K. , Mori Y. H. , Komotori K.
Published: March 2009

In addition to the two different condensation patterns revealed respectively in n‐pentane (bubble)/glycerol and water (bubble)/silicone oil systems in the authors' previous study (1979), a third pattern has been found in methanol (bubble)/silicone oil system: a condensate appears at the rear part of the bubble surface as several blunt drops, turns into a conical tail through coalescence to each other, and finally drops out from the bubble. The possible mechanism as well as the heat transfer characteristics of the condensation process are discussed.
Enhancement of gypsum based kraft process causticized sludge sedimentation rate under inclined condition
Authors: Bhattacharya P. K. , Basu S.
Published: March 2009

An experimental programme for batch and continuous sedimentation was planned to study the feasibility of increasing the rate of sedimentation of the causticized slurry obtained with gypsum as make‐up salt in a Kraft recovery cycle. The studies were conducted in tubular clarifier under vertical and inclined conditions.

For batch sedimentation studies, attempts were made to make a comparative evaluation of existing models. A good agreement was observed with the effective width concept model. The presence of unreacted gypsum in the causticized slurry favours the rate of sedimentation.

For continuous sedimentation studies, enhancement factor variation was observed from 1.39 to 4.20 under inclined conditions at steady state.
Étude de la qualité des eaux de refroidissement des condenseurs principaux des centrales tracy, gentilly 1 et gentilly 2 sises le long du fleuve saint‐laurent
Authors: Gilbert Roland
Published: March 2009

La comparaison de divers paramètres physico‐chimiques a permis de différentier la qualité des eaux de refroidissement des condenseurs des centrales Tracy, Gentilly 1 et Gentilly 2. Les résultats ont fait ressortir une minéralisation des eaux plus prononcée à Tracy qu' à Gentilly 1 et 2, où par contre les suspensoüdes s'y trouvaient en plus grande quantitè. Les paramètres de la conductivité, alcalinité et matières en suspension ont démontré des taux assez constants dans les eaux de Tracy contrairement aux cas de Gentilly 1 et 2 où ils subsissaient d'importantes variations temporelles. L'analyse ionique des eaux révéla la présence des espèces NH4+, Li+, F− et Br− à l'état de traces, tandis que la composition élémentaire des suspensoüdes comprenait des teneurs en chlorures aussi élevées que 5000 ppm. Seuls les critères employés par les concepteurs des systèmes, qui comportent à la fois des paramètres sur l'encrassement et l'entartrage, sont en mesure de relever les variantes notées pour les eaux de ces sites; encore là faudrait‐il appliquer ces critères à un échantillonnage représentatif.
Separation of trace quantities of jetsam in a counter‐current fluidized cascade
Authors: Chan E. W. , Beeckmans J. M.
Published: March 2009

Data are presented on separations involving systems containing small concentrations of iron particles in sand, and of salt particles in activated carbon, in a bottom‐driven 3.66 metre long fluidized cascade. At each fluidization velocity a maximum beneficiation ratio was found at a particular baffle chain velocity. The optimal baffle chain velocity increased with increasing fluidization velocity, and it was larger with 26 mm deep baffles than with 13 mm baffles. An analysis based on a theoretical model led to the conclusion that segregation kinetics are enhanced by the motion of the baffles just above the grid.
The production of the antibiotic patulin in a three phase fluidized bed reactor I. Effect of medium composition
Authors: Berk Dimitrios , Behie Leo A. , Jones Alan , Lesser Barry H. , Maurice Gaucher G.
Published: March 2009

The continuous and semi‐batch production of the antibiotic patulin by immobilized Penicillium urticae cells in a three phase fluidized bed reactor was investigated. A key factor for the success of the process was the limitation of the nitrogen source which increased the longevity of the biocatalyst while keeping cell growth at a low level. The continuous reactor was operated for 360 h during which time the effluent concentration of patulin was maintained at 0.25 mmol/L for 192 h. The total amount of patulin produced by the continuuous run was 35% greater than that obtained in a semibatch run. The pathway efficiency was 0.35 for 192 h indicating the biosynthetic pathway was operating at a high catalytic efficiency.
Pore diffusion model for dye adsorption onto peat in batch adsorbers
Authors: Mckay Gordon , Allen Stephen J.
Published: March 2009

The adsorption of Acid Blue 25, Basic Blue 69, Basic Orange 2, and Disperse Blue 7, on peat has been studied using a series of batch adsorption runs. A model has been developed based on external mass transfer and internal diffusion to explain the concentration decay curves. Two system variables, namely, adsorbate concentration and adsorbent concentration, have been studied. The paper presents a rapid analytical solution for predicting the concentration decay curve in batch adsorbers using peat as a cheap adsorbent to remove various classes of dyestuffs from aqueous solution.

The analytical solution depends on the assumption of a psdeudo‐irreversible isotherm and that the internal diffusion process occurs via a pore diffusion mechanism. External mass transfer coefficients and internal diffusivities have been estimated for the various systems.
Effective diffusion coefficients for oxidation of zinc sulphide pellets
Authors: Rao T. Rajeswara
Published: March 2009

The zinc sulphide oxidation reaction was studied to determine the intrinsic reaction rate constant and effective diffusion coefficients, based on structural (grain) model. Experiments were carried out with small pellets (thickness 0.044 cm – 0.077 cm) in the temperature range of 602°C – 734°C to obtain the reaction rate constant, and with large pellets of thickness around 1 cm, in the porosity range of 0.3–0.5 and temperature range of 744°C – 826°C to determine the effective diffusion coefficients. The results obtained are in good agreement with some of the literature values.
Fluidization characteristics of fine particles
Authors: Chen Peishi , Pei David C. T.
Published: March 2009

A new voidage function is defined based on the Blake–Kozeny equation. This voidage function gives better correlations than those heretofore used in describing minimum fluidization characteristics.

Due to the inter‐particle cohesive forces, the channelling and bubbling often exist in the fluidization of fine particles. In consideration of the channelling effect, a correlation of the fluidization friction factor is proposed. It is also shown in experiments that the channelling in fine particle systems is reduced when coarser particles are added.
Some characteristics of a sparged agitated vessel under foaming — Mechanical control of foaming —
Authors: Ohkawa A. , Sugiyama K. , Sakai N. , Imai H. , Endoh K.
Published: March 2009

Foam‐breaking with a rotating disk mechanical foam‐breaker (MFRD) was studied for a foaming system containing a diluted detergent solution in a laboratory sparged agitated vessel. The change of the foam‐breaking capacity of the MFRD by varying the air sparge rate, the working volume and the impeller speed or the disk diameter was measured. Based on these measurements, empirical equations are presented for predicting the critical foam‐breaking regions of the MFRD fitted with the agitated vessel. The operational range where foam‐breaking with the MFRD can be carried out effectively and economically is also discussed.
Process safety analysis for better reactor cooling system design in the ethylene oxide reactor
Authors: Piccinini Norberto , Levy Guido
Published: March 2009

The operating data for a plant producing 30,000 t/yr of ethylene oxide (EO) are presented, along with a detailed “process safety analysis” of the system used for reaction heat removal. Process safety analysis is a key point in the design procedure for typically critical plants, such as a E.O. reactor.

The paper is primarily directed to identification of the coolant fluid most suitable for the requirements of the process in terms of safety and economy. The evaporating fluid cooling system adopted is examined analytically under both normal and emergency situations with reference to three fluids: dowtherm J, n‐octane and n‐nonane. Nonane was chosen as the coolant because it minimised the temperature gradient along the vertical axis of the reactor (<4°C on the shell side), circulation rate and evaporation pressure.
Extraction of uranium from sea water using biological origin adsorbents
Authors: Tsezos M. , Noh S. H.
Published: March 2009

Waste microbial biomass has been shown to be a good adsorbent for uranium. A small scale pilot plant was operated at Woods Hole Oceanographic Institute in collaboration with the Department of Nuclear Engineering of MIT in order to assess the potential use of the two selected types of microbial biomass to sequester uranium from sea water effectively. The experimental results suggest that factors such as the presence of carbonates in the sea water, suppress substantially the uranium adsorptive uptake capacity of the biomass. The selectivity of the biomass for uranium, is not as good as that of other synthetic inorganic or organic adsorbents as, for example, hydrous titanium oxide.
Mass transfer in a reciprocating plate extraction column — effects of mass transfer direction and plate material
Authors: Shen Z. J. , Rama Rao N. V. , Baird M. H. I.
Published: March 2009

The mass transfer performance of 5 cm diameter reciprocating plate column has been measured with the system n‐butyric acid/kerosene (dispersed)/water (continuous). In most of the tests, the reciprocating plate stack was made of stainless steel which was preferentially wet by the continuous phase. During the mass transfer process the holdup and in some cases the Sauter mean droplet diameter were measured.

The mass transfer effectiveness, expressed as the height of a transfer unit (Hax) corrected for axial mixing, depended on the phase flow rates, the agitation rate and the direction of mass transfer. For continuous to dispersed phase mass transfer (c → d), the mass transfer was more effective, i.e. Hax was lower than for d → c mass transfer under the same external conditions. Qualitative and quantitative observations indicated much larger drop sizes in the d → c case due to enhanced coalescence. Although mass transfer was less effective under d → c conditions, the column capacity was increased. The same effects were also observed when the plate stack was modified by inserting some Teflon plates which were partly wet by the dispersed phase.
Residence time distributions of power law fluids in motionless mixers
Authors: Nigam K. D. P. , Nauman E. B.
Published: March 2009

Motionless mixers, which are also known as static mixers, can often be modeled as open, circular tubes with parabolic velocity distributions except at a few isolated planes where radial mixing occurs via an instantaneous coordinate transformation. The extension of this idea to the processing of non‐Newtonian fluids is straightforward. The parabolic velocity distribution is replaced by whatever fully developed velocity profile is appropriate for the fluid. Experimental confirmation is given for the flow of carboxymethylcellulose solutions through motionless mixers of the Kenics variety. A previous observation that four Kenics elements are equivalent to one plane of complete radial mixing holds for these power law fluids as well as for Newtonian fluids.
Oil blob populations and mobilization of trapped oil in unconsolidated packs
Authors: Wardlaw N. C. , Mckellar M.
Published: March 2009

Residual oil was obtained by waterflooding, under water‐wet conditions, in unconsolidated packs of glass spheres at low capillary numbers. Trapped oil blobs were mobilized in a sequence of decreasing size with subsequent increases in capillary number. The larger blobs, which extend over many adjacent pores, fission repeatedly upon mobilization and the smaller daughter blobs are restranded. There is negligible oil production until the blob population has been reduced to single pore blobs (singlets).

Thus, the critical capillary number for mobilization of significant amounts of oil in unconsolidated bead packs is not related to the original blob size population, but rather to the conditions necessary for mobilization of singlets.
Flow pattern boundaries during condensation: New experimental data
Authors: Rahman M. M. , Fathi A. M. , Soliman H. M.
Published: March 2009

New experimental data on the flow patterns of condensing steam inside horizontal tubes of 13.4 and 25.3‐mm i.d. are presented and discussed. Comparisons with flow pattern maps of adiabatic (gas‐liquid) and condensing flows, as well as individual transition correlations, resulted in good agreements at the mist‐annular and annular‐wavy transitions. All of the horizontal flow pattern correlations tested failed in reasonably predicting the wavy‐slug transition while the results of gas‐liquid flow in upwardly inclined tubes appear to provide some explanation of the trend at this transition.
Kinetics of coke deposition in naphtha pyrolysis
Authors: Kumar P. , Kunzru D.
Published: March 2009

The effect of run time, surface area, reaction temperature and inlet naphtha partial pressure on the rate of coke formation during naphtha pyrolysis has been investigated in a jet‐stirred reactor. The pyrolysis products could be predicted by a model developed earlier for naphtha pyrolysis. Various simplified models for the coke formation involving either the reactant or products were postulated and the kinetic parameters determined by a statistical analysis. The rate of coke formation was best modelled by an approximately second order reaction involving the aromatics.
An empirical method for calculating vapor‐liquid critical points of multicomponent mixtures
Authors: Peng Ding‐Yu
Published: March 2009

The critical temperatures and critical pressures of binary mixtures involving nitrogen, carbon dioxide, hydrogen sulfide, and paraffinic hydrocarbons ranging from methane through n‐heptane as calculated from the Peng—Robinson equation of state have been correlated using a modified compositional function of the Wilson equation in conjunction with the pseudo‐critical properties. The resulting parameters have been used to predict the critical properties of sixty‐one multicomponent systems. The empirically calculated critical temperatures and critical pressures deviate from the rigorously calculated values by an average of less than 1 K and 100 kPa, respectively.