bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement and Prediction of the Solubility of Stearic Acid Polymorphs by the UNIQUAC Equation
Authors: Mirmehrabi Mahmoud , Rohani Sohrab
Published: July 2010

The solubility of stearic acid polymorphs B and C in methanol, 2‐butanone, decane and hexane was measured using a precise gravimetric method. Stearic acid is a molecule with 18 carbons that is highly nonideal in solutions and experimental data show strong deviations from the solubility prediction for ideal systems. It is soluble in both polar and nonpolar organic solvents. From experimental solubility, data the solvent mediated polymorphic transition temperature was found around 30°C. From thermal analysis, temperature and heat of transition from form B to form C and also heat of fusion of form C were found to be 49°C, 20 J/g and 240 J/g, respectively. From experimental solubility data the binary parameters of the universal quasi‐chemical (UNIQUAC) model, for stearic acid were calculated. The UNIQUAC solubility predictions compared very closely with the experimental data.
A General Correlation for the Rise Velocity of Single Gas Bubbles
Authors: Rodrigue Denis
Published: July 2010

A correlation for the terminal rising velocity of a single gas bubble in an infinite Newtonian fluid is proposed. The model is an extension to high Reynolds numbers of a model developed recently by the author (Rodrigue, 2001a). This new equation, which is explicit in velocity, is able to predict the velocity for any bubble volume in any Newtonian fluid.
Analysis of Pre‐filter Based Closed‐loop Control‐relevant Identification Methodologies
Authors: Shreesha C , Gudi Ravindra D.
Published: July 2010

Control‐relevant identification strategies have been variously proposed for open loop model building. In this paper, issues related to control‐relevant model building in closed‐loop schemes are discussed. Various important aspects such as pre‐filter design and plant friendliness of the perturbation signals have been examined. Simulations involving representative problems have been considered from chemical engineering literature to highlight the applicability of the proposed methods.
Simulation and Modeling of Vegetable Market Wastes Pyrolysis Under Progressive Deactivation Condition
Authors: Ray Ruby , Bhattacharya Pinaki , Chowdhury Ranjana
Published: July 2010

The pyrolysis behaviour of predried vegetable market waste has been investigated using TGA within the temperature range 523 to 923 K under inert atmosphere and a comparison has been made with other lignocellulosic materials in order to point out the difference between the pyrolysis of nearly homogeneous and perfectly mixed heterogeneous biomass. Kinetic parameters of the pyrolysis material have been evaluated from the simulation of the TG data. A reaction mechanism involving two parallel 1st order reactions evolving gaseous products lumped as volatiles and solid products lumped as char has been proposed for prediction of rate constants as a function of normalized fractional change. Four kinetic models incorporating the effect of deactivation have been used for this purpose. In another attempt, using concentration independent model of solid deactivation, simulation has been carried out to predict concentration time history of the system components as well as quantitative change of rate constants with the propagation of time.
MHD‐Buoyancy Aiding and Opposing Flows with Viscous Dissipation Effects from Radiate Vertical Surfaces
Authors: Duwairi H. M. , Damseh Rebhi A.
Published: July 2010

The combined effects of forced and natural convection heat transfer in the presence of transverse magnetic field form a vertical surfaces with radiation heat transfer is studied. The buoyancy aided flow and the buoyancy opposing flows are investigated with viscous dissipation effects included in the governing equations. It is found that four parameters can describe the problem under consideration, the mixed parameter, χ, the radiation‐conduction parameter, Rd, the magnetic field parameter, Ha2x/Rex, and the Eckert number, Ec. The local wall shear stresses and the local Nusselt number variations are drawn for different dimensionless groups.
Reaction Kinetics of Decomposition of Acidic Sodium Chlorite
Authors: Deshwal Bal Raj , Jo Hang‐Dae , Lee Hyung‐Keun
Published: July 2010

The decomposition of sodium chlorite was studied in a well‐stirred reactor in a pH range of 2—3 and a temperature range of 15—35°C varying the chlorite concentration. The reaction rate was evaluated by analyzing the consumption of chlorite iodometrically. The rate law was established. Reaction was found to be of the first order with respect to both chlorite and acid concentration. Temperature dependence of the reaction was also studied and pre‐exponential Arrehenius parameter and activation energy were determined. The optimum conditions to generate chlorine dioxide from sodium chlorite are also highlighted.
Liquid Holdup and Pressure Drop Determination in Structured Packing with CFD Simulations
Authors: Raynal Ludovic , Boyer Christophe , Ballaguet Jean‐Pierre
Published: July 2010

It is discussed how Computational Fluid Dynamics (CFD) can be used for hydrodynamics calculations within structured packings. Three dimensional (3D) simulations, in which the influence of mesh size and turbulence models were tested, have been carried out for dry pressure drop determination. Two dimensional (2D) Volume of Fluid gas‐liquid flow simulations have been used for liquid holdup determination. Numerical results are compared to tomographic liquid holdup measurements. Then, a comparison with data from a gas treatment pilot plant shows that wet pressure drop can be predicted by combining these two types of information (dry pressure drop and liquid holdup).
Modelling Heterogeneous Slurry Flows at High Velocities
Authors: Gillies Randall G. , Shook Clifton A. , Xu Jihuai
Published: July 2010

Experiments have been conducted with sand slurries of median diameter 0.09 mm and 0.27 mm in a laboratory test pipeline 0.103 m in diameter. In addition to pressure gradient measurements as functions of mean velocity and in‐situ solids concentration, concentration and velocity profiles have been obtained. The measurements show that the pipeline friction is lower than expected at high velocities. This deviation is of the type that has been predicted in recent theoretical work by Wilson and coworkers. A correlation for the slurry friction at high velocities has been obtained. This correlation has been used to modify the model for predicting friction of heterogeneous slurries at velocities above the deposition condition.
Substitution du chrome dans les bains de passivation de l'acier galvanisé
Authors: Zazoua Ali , Samar Mohamed Elhadi , Kherrat Rochdi , Azzouz Noureddine
Published: July 2010

Il est bien connu que le chrome possède une haute toxicité et des effets cancérigènes. Son remplacement constitue donc une priorité majeure. De ce fait, l'objectif de cette étude est la recherche d'un produit de substitution non toxique ou le moins toxique possible. A cet effet, nous avons effectué des essais comparatifs de performance (vis‐à‐vis du chrome) de deux électrolytes, un hétéropolysiloxane (HPS) et un molybdate. Les résultats obtenus montrent, en plus du caractère non toxique, une très nette supériorité de l'HPS par rapport au chromate et au molybdate au point de vue protection contre la corrosion. Le revêtement de conversion par le molybdate est de moindre qualité anticorrosion, à la fois par rapport à l'HPS et par rapport au chromate.
Carbonation of Magnesium Silicate Minerals: An Experimental Study
Authors: Jia Lufei , Anthony Edward J. , Lin Weigang , Ruan Yuhong , Gora Darius
Published: July 2010

CO2 sequestration by magnesium silicate mineral is the only known process that can permanently store CO2 using a natural feedstock that exists in sufficient quantities to be used practically. Transporting large amounts of mineral over long distances is uneconomical. For Canada to benefit from such a process, identification of suitable Canadian magnesium silicate mineral deposits is crucial. Only carbonation under pressure in NaCl and NaCl/NaHCO3 solutions results in high Mg conversions (40–80%). Among the minerals examined in this study, the serpentines reacted most easily, and peridotite was the most difficult to carbonate. Increasing carbonation pressure to very high levels reduced the degree of carbonation as hydrolysis reactions became competitive with the carbonation process.
A Comparative Study on Acid Leaching of Low Grade Manganese Ore Using Some Industrial Wastes as Reductants
Authors: Ismail Adel A. , Ali Essam A. , Ibrahim Ibrahim A. , Ahmed Mohamed S.
Published: July 2010

Local pyrolusite ore from Om‐Bogma, Sinai, has been treated by sulfuric acid leaching process using either sawdust (C6H10O5)n or lactose (C12H22O11) as reducing agent to produce manganese sulfate. The manganese recoveries were 92.5 and 90.5% at sawdust and lactose respectively.
Numerical Simulation of Pollutant Formation in Precalciner
Authors: Huang Lai , Lu Jidong , Wang Shijie , Hu Zhijuan
Published: July 2010

For cement plants, great attention is being paid to the emission of the pollutant gases, especially NO, CO and CO2. Precalciner is an important equipment in a cement plant in that it can reduce not only the heat loading of rotary kiln but also the NO emission because of its relative low operating temperature. In this paper, the mechanisms for the formation of NO and CO are analyzed and a numerical simulation technique is applied to model the coal combustion, raw material decomposition and concentration distribution of the pollutant gases in a full scale DD‐PRC (dual combustion and denitrator process precalciner). The predicted results agree well with the measured data.
The Effects of Screw Geometry on the Pumping Efficiency of Micro‐Screw Pump
Authors: El‐Sadi Haifa , Esmail Nabil
Published: July 2010

The design of a novel micro‐screw pump for viscous fluid is described. The device consists of a rotating screw in the centre of the channel, connected with a shaft and micro motor. The objective of this research is to investigate the effect of using various screw geometries on the pump performance. Theoretical analysis by finite volume simulations is carried out to study the influence of pitch, diameter of the screw and the thread (flight depth) to evaluate the optimal dimensions for the pump and to obtain the maximum flow rate. When the screw rotates, a net force is transferred to the fluid due to the differential pressure on the depth of the thread and pressure gradient along the screw axis, thus causing the fluid to displace. The three‐dimensional simulations indicate a gradual increase of the average velocity with increasing the screw diameter. The maximum average velocity can be obtained when the ratio between the pitch and screw diameter (pi/d) is 0.6. Effective pumping is achieved by increasing the thread and pitch at maximum screw diameter. The numerical simulation has been validated experimentally.
Design Considerations for Plate and Frame Ultrafiltration Modules by Computational Fluid Dynamics Analysis
Authors: Dal‐Cin Mauro M. , Darcovich Ken , Caza Daniel
Published: July 2010

Pressure and flow maldistributions were studied in a full‐scale industrial plate and frame ultrafiltration module, operating in a Z flow pattern, for the recovery of used motor oils. Solutions were obtained using (1) a three‐dimensional solution of the Navier‐Stokes equation using computational fluid dynamics and (2) Bernoulli's equation and a momentum balance in one dimension. Fluid decelerations and accelerations generated pressure increases and decreases in the distributor and collector, respectively, biasing the flow distribution to the last channel. Several modifications to the original design were evaluated; the most effective was larger distributor and collector diameters, which greatly improved the uniformity of the flow distribution and transmembrane pressure, and reduced the overall pressure drop in a bank. A variable diameter distributor and collector module was designed using the 1‐D model. Flow distribution was significantly improved but also yielded an undesirable overall higher pressure drop and a pressure maldistribution in the bank. The maldistribution of the main inlet manifold to the distributors in the first bank was strongly dependent on the module design. The flow distribution across the width of a channel became uniform within a short distance, essentially eliminating the need to consider this design aspect any further. Flows at the bank outlets, and hence inlets of the following bank, showed uniform lateral distribution in all cases, suggesting that future modelling work can be limited to a fraction of the module width, based on symmetry, in order to gain computational efficiency.
A New Method of Eddy Diffusivity Calculation for Droplets of a Venturi Scrubber
Authors: Rahimi A. , Fathikalajahi J. , Taheri M.
Published: July 2010

An analytical model using eddy diffusivity is applied for predicting droplet concentration distribution and liquid film formation in a Venturi scrubber. By comparing experimental data of film formation reported in literature (Viswanathan et al., 1984) and the results obtained from this model, a semi‐empirical correlation for liquid droplets eddy diffusivity is obtained. The validity of this correlation is confirmed by obtaining good agreement between theoretical and experimental data of droplet concentration distribution and film formation in a Venturi scrubber (Viswanathan, 1998; Viswanathan et al., 1984).
Secondary Cracking of C4 Hydrocarbons from Heavy Oil Catalytic Pyrolysis
Authors: Meng Xianghai , Xu Chunming , Gao Jinsen
Published: July 2010

For C4 hydrocarbons from heavy oil catalytic pyrolysis, the cracking behaviours on catalyst CEP‐1 and quartz sand were investigated in a confined fluidized bed reactor. C4 hydrocarbons show a good cracking ability on CEP‐1, and butene is easier to convert than butane. Only at high reaction temperatures can butane present a good cracking ability. On catalyst CEP‐1, C4 hydrocarbons can undergo not only cracking reactions, but also such reactions as hydrogen transfer, polymerization and aromatization. The conversion of C4 hydrocarbons thermal pyrolysis is high, indicating that free radical reactions play an important part in the secondary cracking of C4 hydrocarbons. The product yields of C4 hydrocarbons pyrolysis on quartz sand are usually lower than those on catalyst CEP‐1. For both catalytic pyrolysis and thermal pyrolysis of C4 hydrocarbons, the selectivity of propene is higher than that of ethene.
Studies on Phenol‐Formaldehyde Gel Formation at a High Temperature and at Different pH
Authors: Banerjee Ranjan , Patil Kiran , Khilar Kartic C.
Published: July 2010

Gel formation characteristic of dilute phenol‐formaldehyde solution in water is studied at an elevated temperature near 140°C. It is experimentally found that at a temperature range of 135°C to 140°C, a solution containing 3.0% phenol with the phenol‐formaldehyde mole ratio 1.0:3.5 forms a gel in the pH range of 9.6 to 12.0. The minimum gelling time is observed at a pH value of 10.4. The gel formation is found to be strongly dependent on the pH at this elevated temperature. An explanation for the gelling behaviour is presented, which is based on an optimum ion concentration of Na+ to initiate the tri‐methylol formation. It is hypothesized that the gel formation begins when concentration of tri‐methylol phenol attains a threshold concentration value. Experimental observations and a kinetic analysis provide support for this hypothesis.
Real‐time Dynamic Optimization of Non‐linear Batch Systems
Authors: Peters Nathaniel , Guay Martin , Dehaan Darryl
Published: July 2010

In this paper, a methodology for designing and implementing a real time optimizing controller for non‐linear batch processes is discussed. The controller is used to optimize the system input and state trajectories according to a cost function. An interior point method with penalty function is used to incorporate constraints into a modified cost functional, and a Lyapunov‐based extremum seeking approach is used to compute the trajectory parameters. Smooth trajectories were generated with reduced computing time compared to many optimizations in literature. In this paper, the theory is applied to general non‐flat non‐linear systems in a true on‐line optimization.
Simultaneous Measurement Bias Correction and Dynamic Data Reconciliation
Authors: Bai Shuanghua , Mclean David D. , Thibault Jules
Published: July 2010

The presence of measurement bias and random noise significantly deteriorates the information quality of plant data. Data reconciliation techniques for steady‐state processes have been widely applied to processing industries to improve the accuracy and precision of the raw measurements. This paper develops an algorithm for simultaneous bias correction and data reconciliation for dynamic processes. The algorithm considers process model error as an important contributing factor in the estimation of the measurement bias and process state variables. It employs black‐box models for the process as would be done when phenomenological models are difficult or impractical to obtain. Simulation results of a distillation column demonstrated that this algorithm effectively compensates constant and non‐constant measurement biases yielding much improved reconciled values of process variables. It has computational advantages over previously proposed algorithms based on non‐linear dynamic data reconciliation because an analytical solution is available when using linear process models to approximate the process.
A Fully Continuous Supercritical Fluid Extraction System for Contaminated Soil
Authors: Ryan M. , Stiver W. H.
Published: July 2010

A fully continuous lab scale supercritical fluid extraction system has been designed, built and tested. The system continuously pumps carbon dioxide under supercritical conditions and soil slurry into a counter‐current contacting column. Delhi Loamy Sand, spiked with approximately 10 mg/g of naphthalene, was used as the testing soil. The soil slurry ranged from 0.0028 g dry soil per g slurry to 0.072 g/g. The operating temperature was 43°C and the operating pressure was 7.7 MPa. Near steady state, fully continuous flow was achieved with runs lasting as long as 2 h. All carbon dioxide samples contained measurable quantities of naphthalene and the measured mass transfer coefficients were as high as 4.6×10−4 s−1.
Flocculation, Retention and Drainage in Papermaking: A Comparative Study of Polymeric Additives
Authors: Cadotte Myriam , Tellier Marie‐Eve , Blanco Angeles , Fuente Elena , van de Ven Theo G. M. , Paris Jean
Published: July 2010

Fibre and filler flocculation, filler retention and drainage, induced by several polymeric retention aids, were compared in laboratory experiments on mixtures of kraft fibres and two calcium carbonate fillers. Some experiments were also performed on thermomechanical pulp and de‐inked pulp fibres. Flocculation was measured by a focused beam reflectance measurement probe. It was found that flocs induced by polyethylene‐oxide (PEO) and cofactor broke up with time and shear and could not be reformed subsequently. Floc strength was the highest for PEO and the weakest for polyethylenimine and polyaluminium chloride. When comparing filler retention under optimal flocculation conditions, we found similar filler retention for all retention aids. Salt did not affect drainage for cationic retention aids, but reduced the drainage rate for PEO. Drainage with PEO was considerably slower than for other retention aids.
Energy Efficiency of Two‐Phase Mixing in a Modified Bubble Column
Authors: Majumder Subrata Kumar , Kundu Gautam , Mukherjee Dibyendu
Published: July 2010

Energy efficiency for gas liquid mixing in a modified downflow bubble column reactor has been analyzed in this paper. Efficiencies of the different parts of the bubble column have been assessed on the basis of energy dissipation. Prediction of the energy dissipation coefficient as well as energy utilization efficiency due to gas‐liquid mixing as a function of different physical, geometric and dynamic variables of the system has been done by correlation method. The distribution of energy utilization in the different zones of the column has also been analyzed. Experiments were carried out with air‐water and air‐aqueous solutions of carboxy methyl cellulose with different concentrations.
Using Dynamic Optimization Technique to Study the Operation of Batch Reactors
Authors: Sun Daim‐Yuang , Lin Pi‐Min , Lin Shu‐Ping
Published: July 2010

How to apply the global optimization technique, simulated annealing, and to explore the operation of batch reactors is addressed in this study. Based on the operating purposes and the imposed constraints, the batch reactor operations are first formulated as two optimal control problems: the maximal yield (or conversion) problem and the minimal operating time problem. The problems are then converted into non‐linear programming problems by the concept of control vector parameterization. The converted problems are solved by the algorithm derived from simulated annealing to determine the optimal operating policy and the performance index. These results are useful in assessing design and operation of batch reactors. In this article, the CSTR model is used to demonstrate the convenience and robustness of the proposed algorithm. Two typical reaction models are used to discuss the operations based on the optimal solutions.
On Measuring Closed‐Loop Non‐Linearity: A Topological Approach
Authors: Tan Guan Tien , Huzmezan Mihai , Kwok K. Ezra
Published: July 2010

The focal point of this paper is to develop a measure of closed‐loop non‐linearity. In this work, the Vinnicombe metric and the Quasi‐Linear Parameter Varying representation of a non‐linear system are exploited for this purpose. It is expected that the proposed measure can serve as a decision making tool for control engineers when considering whether a linear or a non‐linear control strategy should be employed to close the loop for a non‐linear system operating in a prescribed range.
Non‐Uniform Distribution of Two‐Phase Flows through Parallel Identical Paths
Authors: Grace John R. , Cui Heping , Elnashaie Said Seh
Published: July 2010

When a single‐phase fluid splits, passes through identical paths in parallel, and then recombines, the flow distributes itself uniformly among the multiple paths. However, when multi‐phase suspensions travel through identical parallel paths, the flow distribution can be significantly non‐uniform. Although the uniform distribution is a solution of the governing equations, this solution may be an unstable steady‐state solution between two or more stable solutions, or one of an array of possible steady‐state solutions. This multiplicity has arisen in practice for multiple vertical channels within fluidized beds, for cyclones in parallel, and for distributed feed suspension flows. Simple theories are employed to explain the principles involved for two cyclones and for a pair of risers in parallel.
Comparative Analysis of Single‐Cascade Five‐Zone and Two‐Zone SMB Systems for the Separation of a Ternary Amino Acid Mixture
Authors: Jo Se‐Hee , Kim Jeung Kun , Yoo Chang Geun , Kim Jin‐Il , Koo Yoon‐Mo , Mun Sunyong
Published: July 2010

A ternary separation usually requires the use of two simulated moving bed (SMB) units in series. Since an increase in the number of SMB units leads to a significant increase in capital and operational costs, the use of a single SMB unit is preferred if its structure can be modified to treat a ternary separation. Such a modified single SMB unit has been typified by a five‐zone SMB or a two‐zone SMB so far. The separation performances‐of a five‐zone SMB and a two‐zone SMB are compared in this paper by using the ternary amino acid mixture as a model system. A five‐zone SMB is designed with the safety margin method while a two‐zone SMB is optimized using genetic algorithm. A five‐zone SMB based on the maximum allowable safety margin, although it may not guarantee the global optimum solution, results in much better separation performance than a two‐zone SMB at its global optimum state.
Influence of spectrophotometer slits on tristimulus calculations
Authors: Stearns E. I.
Published: July 2010

The importance of the slit function is discussed in connection with the calculation of tristimulus values by the weighted‐ordinate method. The influence of slit‐function shape on wavelength calibration is shown. The influence of slit‐function range on photometric accuracy is discussed. It is shown how slit‐function range affects the choice of optimum radiance‐factor measurement interval and vice versa.
A CuIINiII Complex with Ethylenediamine: Crystal Structure and Ferromagnetic Behaviour of an Aqua‐Bridged Heterometallic Chain Containing Ambidentate Ni(OAc)42– Blocks
Authors: Nesterova Oksana V. , Petrusenko Svitlana R. , Nesterov Dmytro S. , Kokozay Vladimir N. , Skelton Brian W. , Jezierska Julia , Linert Wolfgang , Ozarowski Andrew
Published: July 2010

A one‐pot reaction of copper powder and nickel and ammonium acetates in a CH3OH solution of ethylenediamine (en) yields a unique 1D aqua‐bridged polymer [Cu(en)2(μ2‐H2O)2Ni(OAc)4]n·4nH2O (1) with an ambidentate Ni(OAc)42– fragment that has not been previously characterized. The basic structural motif of 1 contains a previously unreported heterometallic M(μ2‐H2O)M′ aqua‐bridge chain with alternating metal atoms. A complex system of N/O–H···O hydrogen bonds strengthens the polymeric chains and links them into a supramolecular three‐dimensional network. Variable‐temperature magnetic susceptibility measurements of 1 revealed a weak ferromagnetic coupling (J = 1.1 cm–1) between the paramagnetic copper(II) and nickel(II) ions, which is transmitted through the oxygen bridges.
Dual Luminescent Dinuclear Gold(I) Complexes of Terpyridyl‐Functionalized Alkyne Ligands and Their Efficient Sensitization of EuIII and YbIII Luminescence
Authors: Li Xiu‐Ling , Zhang Ke‐Juan , Li Juan‐Juan , Cheng Xin‐Xin , Chen Zhong‐Ning
Published: July 2010

Reaction of (tpyC6H4C≡CAu)n {tpyC6H4C≡CH = 4′‐(4‐ethynylphenyl)‐2,2′:6′,2″‐terpyridine} with diphosphane ligands Ph2P(CH2)xPPh2 (x = 2 dppe, 3 dppp, 4 dppb, 5 dpppen, 6 dpph) in CH2Cl2 afforded the corresponding dual luminescent binuclear gold(I) complexes [(tpyC6H4C≡CAu)2(μ‐dppe)] (1), [(tpyC6H4C≡CAu)2(μ‐dppp)] (2), [(tpyC6H4C≡CAu)2(μ‐dppb)] (3), [(tpyC6H4C≡CAu)2(μ‐dpppen)] (4), [(tpyC6H4C≡CAu)2(μ‐dpph)] (5). Crystal structural analysis of complexes 1·2CH2Cl2 and 2·2CH2Cl2 show that the terpyridine moieties are free of coordination in these gold(I)‐acetylide‐phosphane complexes. Spectrophotometric titration between complex 1 and [Eu(tta)3] (Htta = 2‐thenoyltrifluoroacetone) or [Yb(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) gave a 2:1 ratio between Ln(β‐diketonate)3 (Ln = Eu, Yb) units and the complex 1 moiety, indicating the formation of Au2Ln2 complexes. Both the luminescence titrations and the luminescence quantum yields of Au2Ln2 (Ln = Eu, Yb) solutions show that the energy transfer occurs efficiently from the binuclear gold(I) antennas 1–5 to EuIII and YbIII centers, and all complexes 1–5 are good energy donors for sensitization of visible and NIR luminescence of EuIII and YbIII ions.
Zur Abgrenzung von Chamaecyparis SPACH und Cupressus L. (Cupressaceae) und die systematische Stellung von Cupressus nootkatensis D. DON [= Chamaecyparis nootkatensis (D. DON) SPACH]
Authors: Jagel A. , Stützel Th.
Published: July 2010

Die Samenzapfen der Gattungen Chamaecyparis und Cupressus (Cupressaceae) werden morphologischen Untersuchungen zum Zeitpunkt der Blüte sowie morphogenetischen Untersuchungen unterzogen und Unterschiede zwischen den Gattungen herausgearbeitet. Zapfendiagramme von neun Arten werden gegeben. Chamaecyparis hat am distalen Zapfenende immer mindestens ein steriles Paar Zapfenschuppen und ein gut ausgebildetes Terminalstück. Zusammen mit den distalen, sterilen Zapfenschuppen nimmt dieses am Aufbau des reifen Zapfens teil. Die Samenanlagen stehen auf den Zapfenschuppen scheinbar in einer Reihe und werden von innen nach außen angelegt. Dem zuerst angelegten Paar von Samenanlagen können nach beiden Seiten weitere Paare von Samenanlagen folgen. Nur bei Ch. obtusa tritt häufiger eine einzelne mediane Samenanlage in der Ontogenese auf, welche später als die mittleren beiden Samenanlagen der Zapfenschuppen angelegt wird. In reifen Zapfen ist diese seltener zu finden. Dieser Sachverhalt führt zu der Hypothese, dass die Samenanlagen nicht in einer Reihe, sondern in ein bis vier Reihen, die jeweils nur zwei Samenanlagen tragen, stehen. Die mediane Samenanlage bei Ch. obtusa stellt die ausnahmsweise gebildete mediane Samenanlage der ersten Reihe in zentripetaler Anlegung dar, die dann drei Samenanlagen enthält. Die Bestäubungstropfen bei Chamaecyparis stehen einzeln und verlaufen nicht miteinander. Bei der Gattung Cupressus tritt am Zapfenende nirgends ein auffälliges Terminalstück auf. Am distalen Ende stehen entweder sterile oder fertile Zapfenschuppen. Letztere kommen bei allen Arten vor, bei einigen Arten (z. B. C. arizonica, C. duclouxiana, C. nootkatensis) sogar über‐.
Magmatic pulses in the emplacement of plutons
Authors: Harry W. T. , Richey J. E.
Published: July 2010

Doubt is cast on the general assumption that individual plutonic units were each emplaced in one intrusive act. Lack of internal contacts does not prove this assumption. It is suggested that all plutonic units may well have been intruded as a series of magmatic pulses, a number of temporally distinct injections that succeeded each other in such a way that none could develop clearly intrusive contacts against its immediate predecessor. This mechanism would ease the difficulty of explaining how plutons made room for themselves.
PT‐diagram of the system SiO2‐H2O
Authors: Ostrovsky I. A.
Published: July 2010

The high‐temperature and medium‐pressure part of the PT‐diagram of the system SiO2‐H2O has been investigated experimentally. The equilibrium diagram is discussed in the light of Schreinemakers general theory of PT‐diagrams.

The triple invariant point cristobalite + tridymite + quartz lies at 1190°C and 1430 atm. Neither cristobalite nor tridymite are stable at high pressure. Quartz may precipitate from the melt at a very high temperature (1360°C and higher), if the pressure is great enough, and if the water content is low.

Using new experimental and published data a PT‐diagram of the system SiO2‐H2O in the large PT‐region is given.
Joints and other structures in the silurian rocks of the southern Shap Fells, Westmorland
Authors: Moseley F.
Published: July 2010

The Coniston Grits and Bannisdale Slates south of Shap are folded into the major Bannisdale Syncline, an asymmetrical fold with a longer northwest limb, a half wave length exceeding 5 miles, and numerous minor parasitic folds with half wave lengths ranging from 200 yds to 2 or 3 yds. These minor folds generally plunge from 5° to 10° to the northeast and occur in belts of tight folds which alternate with belts of steeply, uniformly dipping strata. It is notable that the axial planes of the folds are not parallel to the cleavage and in fact the trend of the former (005°) is about 5° oblique to the latter (060°). There are also complementary dextral and sinistral wrench faults and numerous sets of joints related both to the folds and the faults. The joints present distinctly different patterns on opposing limbs of the minor folds and it is suggested that they formed at different stages of the orogeny. The earliest phase, shortly after initiation of folding, is thought to have been “wrench type” joints, subsequently folded and succeeded by post folding dextral and sinistral “wrench” joints accompanied by Reidel shear and kink bands, and then finally by high and low angle tension joints at a late stage in the orogeny.
A geological interpretation of the aeromagnetic maps of the continental shelf around Orkney and Shetland
Authors: Flinn Derek
Published: July 2010

The distribution of eleven different patterns of magnetic anomalies over the maps is shown. The individual patterns overlying the land are correlated with the underlying geology, and on the basis of this correlation a geological interpretation of the sea areas of the aeromagnetic survey is proposed. The outcrops of crystalline rocks are largely confined to the present land areas, so that in most places the sea floor is composed of Devonian or younger rocks. The Newer Granites are classified into three types based on their magnetic properties. The Great Glen fault passes through Shetland where it causes a 65 km dextral displacement of the Devonian rocks and an unknown but possibly much larger displacement of the older rocks.
Trilobite tracks and other trace fossils from the Upper Cambrian of North Wales
Authors: Crimes T. P. , Herdman Jane
Published: July 2010

Trace fossils are recorded from eight localities within Upper Cambrian (Ffestiniog Stage) strata in North Wales. Trilobite furrows (Cruziana), resting impressions (Rusophycus), walking and striding tracks (Diplichnites), sideways grazing tracks (Dimorphichnus) and swimming grazing marks (Monomorphichnus, gen. nov.) are described, largely on the basis of over 500 collected specimens, and are figured together with examples of other trace fossil genera includingRouaultia, PhycodesandMonocraterion.The trilobite traces are used to investigate the varied methods of locomotion of the animais. They also indicate the morphology of some of the trilobite hard and soft parts from which it is inferred that most of these traces were probably made by a population consisting of a small number of closely allied species of trilobites belonging to the Olenid family.
The structural geology of the North Roe area of Shetland
Authors: Pringle I. R.
Published: July 2010

The metamorphic rocks forming the area are divided into four groups separated by easterly dipping shear zones. The two western groups are orthogneisses and the eastern two are metasediments. The structures indicate movements from east to west with the most westerly group of gneisses having been a stable block during the movements. The metamorphic and structural events in the area are considered to be part of the Caledonian Orogeny. A Devonian granophyre is intruded into the metamorphic rocks. Small areas of Devonian type sediments occur overlying the metamorphic rocks.
A magnetic fabric study of Late Whitcliffian (U. Silurian) siltstones from the Welsh Borderland
Authors: Bailey R. J. , Rees A. I.
Published: July 2010

The uppermost Whitcliffian strata of the Welsh Borderlands record the final phase of marine sedimentation in the Silurian basin and shelf environments. They give way transitionally to the succeeding non‐marine Lower Old Red Sandstone. As a contribution to the understanding of the change from marine to continental facies, the magnetic fabric method was used to obtain palaeocurrent data for the uppermost Whitcliffian. The results confirm that the uppermost Whitcliffian palaeocurrent pattern is essentially “Silurian” in character and does not foreshadow the deltaic and littoral patterns of sediment distribution observed in the basal Old Red Sandstone.
Carboniferous Bryozoa from County Tyrone
Authors: Owen D. E.
Published: July 2010

Six species of Bryozoa, three new, of Upper Visean age are described from Tullaghoge, County Tyrone, Ireland. The assemblage suggests shallow water conditions subject to wave action. The new species areDyscritella tyronei, Stenophragmidium incrustans, andSulcoretepora? ramosa.
Slaty cleavage associated with sandstone dykes in the Harlech Dome, North Wales
Authors: Bates D. E. B.
Published: July 2010

Slaty cleavage in the Llanbedr Slates (Lower Cambrian, North Wales) is developed parallel to a number of sandstone and grit dykes, entrained both upwards and downwards from arenaceous layers. The implications of these observations are discussed and compared with modem and fossil analogues.
Magnetic properties of Precambrian pillow lavas of the Mona Complex and a related dyke swarm, Anglesey, Wales
Authors: Piper J. D. A.
Published: July 2010

Four palaeomagnetic sites in Monian pillow lavas of the Gwna Group from Llanddwyn Island, Anglesey, yield statistically‐significant groups of magnetic directions after demagnetising in low fields. A palaeomagnetic pole of 57°E, 16° S is derived after dip correction assuming no plunge components, and is believed to apply to the time of formation of the pillow lavas (ca. 600 m.y.). By contrast to young pillow lavas these rocks have poor magnetic stability and low Köenigsberger ratios although petrologic features are comparable; this is believed to be due to replacement of the finer grain size fractions of the titanomagnetite. Five of the seven dolerite dykes cutting the Monian rocks here yield pole positions close to those of Upper Silurian to Lower Devonian rocks from elsewhere in Britain confirming that they are Palaeozoic in age.
A structural cross‐section from the Aureole of the Main Donegal Granite
Authors: Hutton D. H. W.
Published: July 2010

Seven phases of deformation are recognised in Dalradian metasediments within the NW aureole of the Main Donegal Granite. Major NW facing F2 folds (the Aghla Anticline and Errigal Syncline) refold an originally NW facing slaty cleavage, which is usually parallel to bedding. D3 structures cross‐cut the major F2 folds and verge and face to the SE on their normal limbs. A fourth phase of deformation intensifies towards the granite contact and is shown to be broadly coeval with intrusion and responsible for a major structure in the aureole. Three later phases are variably developed throughout the aureole. The kinematics of F4 folds in relation to the granite intrusion are briefly discussed.
The envjronment of deposition of the caradoc alternata limestone and contiguous deposits of salop
Authors: Hurst J. M.
Published: July 2010

The middle Caradoc rocks of Salop are a mosaic of sedimentary facies deposited in nearshore environments. The uppermost Horderley Sandstone in the Onny Valley is interpreted as formed by migrating marine bars and proximal and distal stonn deposits. The time equivalent Chatwall Sandstone of the Chatwall district is interpreted as a beach sequence. The overlying Alternata Limestone is a product of both proximal and distal storm deposits, associated with marine bars, in which different faunal assemblages are mized. Correlation of local sections is difficult due to facies and faunal changes and non‐deposition events. Based on a sedimentary model and palaeoecological information it is suggested that the Alternata Limestone in the Chatwall area is older than elsewhere, and that the base of the Cheney Longville Flags youngs southwards. Four faunal events are defined based on transect collecting, discriminant function and cluster analysis. These are theHowellites antiquior, Dalmanella leptaandBancroftina robusteAssociations and theHeterorthis alternatainterregnum.
Jointing and minor tectonics of the N. Crop of the South Wales coalfield between kidwelly and black mountain, S. Wales
Authors: Roberts J. C.
Published: July 2010

Joints, minor faults and mineral veins were recorded at 334 stations between Kidwelly and Black Mountain, S. Wales. A systematic pattern occurs with joint sets striking at 360°, 340°, 290°, 250°, and 210°. Minor faults and shear planes exhibit both strike and dip‐slip displacements. The jointing is considered to have formed quite early during folding, and both joints and faults can be attributed to a principal compression acting almost N‐S and subparallel to bedding. Phases of dilation are recorded by sets of mineral veins. All the deformational structures are considered to be of Armorican age.
Old red sandstone sedimentation—an example from the brownstones (highest lower old red sandstone) of south central wales
Authors: Tunbridge Ian P.
Published: July 2010

The Brownstones form the highest Lower Old Red Sandstone in South Wales and the Welsh Borderlands. Sections from the Brecon Beacons of Central South Wales consist of laterally extensive sheets of interbedded sandstone and siltstone. Facies sequence A consists of parallel laminated sheet sandstones and siltstones and is interpreted as a sandy sheetflood and distal muddy floodflat association. Facies sequence B comprises sheet sandstones composed of multistorey channel fills, small calcrete‐clast filled channels and massive siltstones with thin interbedded sandstones. This sequence is interpreted as low sinuosity channel deposits merging laterally and downslope into a muddy flood‐basin, with calcrete clasts infilling intrabasinal channel systems. Facies sequence C consists of multistorey sandstones and is interpreted as a proximal low sinuosity channel system. The Brownstones of the Brecon Beacons formed on an extensive alluvial plain with low sinuosity sand‐bed channels merging downslope into sheetfloods and muddy floodflats, in a system broadly analogous to that of the Eyre Basin of South Australia.
Ashgill trilobite faunas from the Llŷn Peninsula, North Wales, U.K.
Authors: Price David
Published: July 2010

The Crugan Mudstone Formation is formalized and the Dwyfor Mudstone Formation proposed for restricted Ashgill outcrops respectively near Llanbedrog and Llanystwmdwy in the Llŷn Peninsula. These mudstones contain brachiopods of the Foliomena fauna and a total of 26 determined genera of trilobites, one, Pseudosphaeroxochus represented by a new species, P. seabornei sp. nov. Elements of the trilobite fauna are used to demonstrate a Rawtheyan age for the mudstones. The generic assemblages both of brachiopods and of trilobites present in the mudstones indicate relatively deep water environments of deposition, that of the Dwyfor Mudstones probably being the deeper. The trilobites belong to what is here described as the Nankinolithus‐Opsimasaphus association.
Pleistocene non‐marine molluscs from Cala Salada, Ibiza
Authors: Paul C. R. C.
Published: July 2010

A 20 m Pleistocene section at Cala Salada, Ibiza, exposes three eolianites with interbedded silts and gravels. The basal eolianite has steep cross beds and represents a migrating dune, the upper two lack steep cross beds but contain abundant rhizomorphs and represent calcareous sand trapped by vegetation. Internal moulds of non‐marine molluscs occur only in the lower silts and the base of the middle eolianite. Within the lower silts are two cycles of upwards increasing diversity and abundance followed by local extinction, which probably reflect local ecological changes rather than major climatic fluctuations.

The fauna contains eleven species, including Tudorella ferruginea hitherto known only from the eastern Balearics, and an extremely small form of Rumina decollate.
Historical valley alluviation in mid‐Wales
Authors: Lewin J. , Bradley S. B. , Macklin M. G.
Published: July 2010

Recent developments on a floodplain reach of the Afon Ystwyth are analysed with the aid of five sets of maps and ten of air photographs covering the period since 1800. The area has been subjected to around 3 m of aggradation and then incision in association with historic metal mining. Analysis of sediment texture and metal concentrations allows subdivision of the mining‐associated sediments; C/M plots and shape analyses allow a distinction between proglacial, mining aggradation, and wandering river phases. The distinctive style of aggradation, involving overbank gravel splays and interfingering fines, and the lagged response of channel and sedimentation, relate largely to alterations in sediment supply rates. This has relevance for the interpretation of Quaternary fills and river terraces and for contemporary river management.
The petrology and geochemistry of intrusive alkaline rocks of Elchuru, Prakasam District, Andhra Pradesh, India
Authors: Nag S. , Chakravorty P. S. , Smith T. E. , Huang C. H.
Published: July 2010

The Elchuru alkaline igneous intrusion is an arcuate‐shaped ring complex, approximately 16 km2in area, cropping out in the Eastern Ghats high grade metamorphic series. It is part of an alkaline province composed of a number of intrusions which range from ijolite‐melteigite to alkali gabbro (viz. malignite, melalusitanite, shonkinite) and then to hypersolvus nepheline syenite followed by subsolvus nepheline syenite. The complex is cut by late lamprophyric dykes. A nephelinized alkaline gneiss, within the investigated complex, is the only deformed rock type and is regarded as an older unit not related to the comagmatic series. The remainder of the complex was emplaced post‐tectonically. Sovitic carbonatite is a conspicuous Iithologic unit associated with the complex.

Chemical analyses of 19 selected samples for 13 major oxides and 5 trace elements (Rb, Ba, Sr, Zr and Nb) are presented to establish a geochemical model for the investigated complex.

The mineralogy, petrography and geochemistry of the rocks of the Elchuru Alkaline Complex suggest that it was formed by differentiation of an initially alkali‐rich ijolitic magma as reflected in the crystallization of nepheline, kaersutitic amphibole and alkali feldspar. With progressive increase in alkali feldspar content (volume percentage) the ijolite passes to malignite and then nepheline syenites. Amphibole shows sodic enrichment from a dominant calcic variety. Pyroxene, likewise, shows sodic enrichment following the scheme salite‐ferrosalite to aegirine‐augite. The igneous cycle closes with the intrusion of biotite lamprophyre.

There is a systematic increase in total alkalies (Na2O+K2O) and decrease in CaO from the early mafic rocks to the syenitic rocks. The alkali‐lime index of the complex is 48 indicating its strongly alkaline nature (Peacock 1931), and they are miaskitic in character (agpaicity index <1, Currie 1976). Such miaskitic complexes are associated with carbonatites (Heinrich 1966).
A late Devensian glaciolacustrine fan‐delta at Rhosesmor, Clwyd, North Wales
Authors: Thomas G. S. P.
Published: July 2010

Glacigenic sediments exposed at Rhosesmor, Clwyd, North Wales, were deposited in a small proglacial lake ponded by the stagnating margin of the Late Devensian Irish Sea icesheet. Three major fades assemblages are identified and show a prograding sequence of topset, foreset, and bottomset deposits associated with two Gilbert‐style deltas stacked one above the other. The lower delta is associated with a lake level at c. 180 m OD. A subsequent ice‐marginal readvance raised the lake to c. 192 m OD, drowned the lower delta and caused the growth of a second delta by an iceward shift of facies. It is estimated that the life of the lake was of the order of 90 years during which average sediment in‐fill amounted to some 4±104 m3 per annum.
The ecological, significance of variation in the generic composition of Rawtheyan (late Ordovician) trilobite faunas from North Wales, U.K.
Authors: Price D. , Magor P. M.
Published: July 2010

Contemporaneous trilobite faunas from Rawtheyan rocks forming the local base to the Ashgill Series change in their generic composition along the outcrop between Bala and Corris. The change, although overall a very marked one, is progressive and is held to reflect original ecological control along a depth gradient between a locally elevated area around Bala and the deeper central part of the Welsh Basin. Along this intrabasinal slope three distinctive trilobite generic associations–the Ceraurinella‐Encrinuroides Association, the Nankinolithus‐Opsimasaphus Association and the Novaspis‐cyclopygid Association–succeeded each other in gradually deeper water. Faunas of all three associations differ markedly from contemporaneous faunas of shallower shelf environments.
The Westphalian D floral biostratigraphy of Saarland (Fed. Rep. Germany) and a comparison with that of South Wales
Authors: Cleal C. J.
Published: July 2010

The fossil plant distribution in the Carboniferous of Saarland indicates that the base of the Westphalian D is in the upper Luisenthal Formation. Two distinctive changes in the middle Westphalian D floras are noted in the Heiligenwald Formation, very similar to those reported in the Upper Pennant Measures of South‐Wales. These changes in the floras, recognizable in two distantly separated coalfields, are made the basis of a threefold biozonation of the Westphalian D. This is the most detailed biostratigraphical resolution presently available for non‐marine strata of this age.