bluuebunny/crossref_metadata_2025 huggingface dataset:
Injury Risk Among Oil and Gas Extraction Workers by Company Type and Size
Authors: Hill R. D. , Conway G. A. , Somervell P. D.
Published: March 2009

Introduction

The oil and gas extraction industry employs 400,000 workers. During 2003-2007, the fatality rate among oil and gas extraction workers was nearly eight times that for all U.S. workers (30.0 vs. 4.0 per 100,000 workers). Occupational fatality rates among these workers are high, and vary with the level of drilling activity. In addition, injury risk may be associated with other factors, such as company type and size. The purpose of this study was to characterize the differences in risk of fatal injury according to company type and size during 2003–2007.

Methods

Data from the Bureau of Labor Statistics, Census of Fatal Occupational Injuries were utilized for this study. Company size was defined as small (fewer than 20 workers); medium (20–99 workers), and large (100 or more). For company type, companies were characterized as operators, drilling contractors and service companies. Relative risks were calculated to compare occupational fatality rates among different groups of companies.

Results

Workers employed by small companies were three and five times as likely to suffer a fatal injury compared with workers from medium and large companies, respectively. There were also substantial differences between company types, independent of company size. Workers employed by drilling contractors were most at risk of fatal injury. The fatality rate in drilling companies was three times that for operators, and 1.5 times the rate among service companies. The size effect held true within each company type; the company type effect held true among small companies.

Conclusions

The workers at highest risk were those employed by small companies, particularly small drilling contractors. These findings may help safety professionals develop workplace solutions and conduct outreach and training for the industry's most at-risk workers.
Microbial Degradation of Benzyldimethyl Hexadecylammonium Chloride (BDHAC) Used in Oilfield Chemical Formulations
Authors: Bassey D. E. , Grigson S. J. W. , Mitchell W. J.
Published: March 2009

Following enrichment in its presence, four strains of bacteria, isolated from marine sediments, were shown to degrade the quaternary ammonium surfactant Benzyldimethyl Hexadecylammonium Chloride (BDHAC) in a minimal salts medium. The bacteria were identified by 16S rDNA sequencing, were shown to belong to several genera and were identified as Bacillus niabensis, Bacillus subtilis, Thalassospira sp, and Sporosarcina sp. Initial investigations have shown that the bacteria are capable of degrading BDHAC when it is present at concentrations in the range 2 – 4 mg/ml. In media containing BDHAC, up to 90% was degraded within 7 days, but this supported only limited growth of the bacteria. Preliminary analysis of samples after degradation experiment by ESI-MS/MS produced a peak with a parent-daughter ion transition of 136.0→91.0, corresponding to N, N-dimethylbenzylamine. The presence of this potential metabolite suggests the cleavage of the C alkyl-N bond as a step in BDHAC catabolism.
Process Check: What Is Driving Alternatives Analysis in Environmental-Impact Assessment for Major Capital Projects?
Authors: Khalsa A. S. , Boyd H. , Slocum D.
Published: March 2009

Application of a companywide environmental management system (EMS) and guidelines is a best practice for environmental performance assurance in the oil and gas industry because it helps to institutionalize environmental protection efforts. While implementation of these systems and guidelines is a very positive step toward promoting sustainability and environmental stewardship, it sometimes fall short of fulfilling this goal with regards to designing and developing the most sustainable new projects possible. A key to this shortcoming is the alternatives analysis element of the Environmental Impact Assessment (EIA) process. The EIA process is typically a company's first in-depth look at environmental components of a project and proper application can make the difference in defining the sustainability of development projects.

EIA is most valuable when used not only to help identify, predict, evaluate and mitigate potential impacts of proposed developments upstream in the decision-making process, but to support a robust decision-making process about the basic design and scope of the project. Environmental and social impacts of projects tend to be readily predictable, but unfortunately not readily quantifiable. Therefore, decision making tools used in alternatives analysis may not adequately reflect the external environmental and social costs associated with a given project. For this reason, economic and technological considerations are often unintentionally prioritized in the decision making process and become the true driving force of early project decision making. Environmental and social concerns are less often addressed up front, and are more often addressed in the EIA's Environmental Management Plan (EMP) where they are managed over the life of the project and sometimes beyond.

While EMPs are vital to minimizing and mitigating environmental and social impacts, there are risks to allowing environmental and social concerns to be addressed only after most technical and design planning has been largely finalized. This paper will demonstrate the importance of addressing environmental and social considerations through EIA alternatives analysis early in the project decision-making process, review cases in which this has or has not been accomplished and review tools that can be used by decision makers to support alternatives analysis in EIA. The tools explored, sustainability appraisal, true cost accounting, scenario planning and modeling software, take into consideration the true costs of environmental and social impacts. Their application in EIA alternatives analysis can help assure more sustainable projects.
CO2 Sequestration Permitting at the SECARB Mississippi Test Site
Authors: Riestenberg D. E. , Koperna G. J. , Kuuskraa V. A. , Esposito R. , Harrison K. , Berry R. , Sparks J. , Rhudy R.
Published: March 2009

Mississippi Power Company's Victor J Daniel, Jr. electric generating facility is hosting a United States Department of Energy (USDOE)-sponsored CO2 sequestration demonstration as part of the Southeast Carbon Sequestration Regional Partnership. The goal of the project is to demonstrate safe and secure CO2 storage in a deep saline reservoir. Prior to well drilling and injection operations, the primary focus of the project was on public acceptance and permitting of such activities. Three permits were required for the project, a USDOE-NEPA environmental questionnaire, a Mississippi Oil and Gas Board (MOGB) drilling permit, and a Mississippi Department of Environmental Quality (MDEQ) underground injection control (UIC) permit.

The injection well was permitted under the Environmental Protection Agency's Class V Experimental Technology guidelines through the Mississippi Department of Environmental Quality; however, the well was constructed to Class I (non-hazardous) standards. To our knowledge, this is the first CO2 storage well permitted to Class I standards in the United States and certainly the first in the State of Mississippi. This paper will detail the permitting activities for this demonstration project.
Risk Comparison of Alternative Fuels
Authors: Freeman J. L. , Erdal S.
Published: March 2009

The purpose of this paper is to identify and assess risks related to alternative fuels, and relate those risks to public health and life cycle questions. Using the school bus fleet of the Chicago Public Schools as a model, this paper compares the environmental health and safety impact of current diesel fuel usage with that of increased use of alternative technologies and fuels.

Four alternative fuels have been studied: Low sulfur diesel (baseline), biodiesel (BD20), ethanol-diesel blends (ED10), and compressed natural gas (CNG) from renewable feedstocks. Impact was assessed utilizing the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) 1.7 Well to Wheel model.
Estimation of missing precipitation records integrating surface interpolation techniques and spatio-temporal association rules
Authors: Teegavarapu Ramesh S. V.
Published: March 2009

Deterministic and stochastic weighting methods are the most frequently used methods for estimating missing rainfall values. These methods may not always provide accurate estimates due to their inability to completely characterize the spatial and temporal variability of rainfall. A new association rule mining (ARM) based spatial interpolation approach is proposed, developed and investigated in the current study to estimate missing precipitation values at a gauging station. As an integrated approach this methodology combines the power of data mining techniques and spatial interpolation approaches. Data mining concepts are used to extract and formulate rules based on spatial and temporal associations among observed precipitation data series. The rules are then used to improve the precipitation estimates obtained from spatial interpolation methods. A stochastic spatial interpolation technique and three deterministic weighting methods are used as interpolation methods in the current study. Historical daily precipitation data obtained from 15 rain gauging stations from a temperate climatic region (Kentucky, USA) are used to test this approach and derive conclusions about its efficacy for estimating missing precipitation data. Results suggest that the use of association rule mining in conjunction with a spatial interpolation technique can improve the precipitation estimates.
Model of behaviour of conductivity versus pH in acid mine drainage water, based on fuzzy logic and data mining techniques
Authors: Jiménez A. , Aroba J. , de la Torre M. L. , Andujar J. M. , Grande J. A.
Published: March 2009

Acid Mine Drainage is a water pollution type characterized by several topics such as high acidity, sulfate and heavy metal concentrations. One of the chemical characteristics is the absence of correlation between pH and conductivity, as could be expected. This last parameter is well correlated with other variables such as sulfate concentration and can be used as a field assessment. The absence of pH/conductivity correlation is largely discussed by several authors. In this work, the use of fuzzy logic algorithms in a large temporal database (over 20,000 records) has allowed us to study the “hidden” relation between them. This work finds this correlation, with some conditions such as the range of pH where it happens. Maybe the study of the usual range of pH values in previous studies has disturbed the correlation because of other chemical processes.
Probabilistic building block identification for the optimal design and rehabilitation of water distribution systems
Authors: Olsson Ralph J. , Kapelan Zoran , Savic Dragan A.
Published: March 2009

The multi-objective design and rehabilitation of water distribution systems (WDS) is defined as the search for the set of system designs which offers the best trade-off between competing design objectives. Typically these objectives will consist of the cost of implementing a system design and a measure of the performance of that system. These measures are often in competition since improvements in the performance of a system generally come at a cost. Here three genetic algorithms which use probabilistic methods to identify building blocks—the Univariate Marginal Distribution Algorithm (UMDA) (Mühlenbein 1997), the hierarchical Bayesian Optimisation Algorithm (hBOA) (Pelikan 2002) and the Chi-Square Matrix methodology (Aporntewan & Chongstitvatana 2004)—are compared to the well-known multi-objective evolutionary algorithm NSGAII (Deb et al. 2002) for the multi-objective design and rehabilitation of water distribution systems. For single-objective problems the identification of building blocks has been seen to make evolutionary algorithms more scalable to large problems than simple genetic algorithms. In this paper these algorithms are shown to offer significantly better solutions than NSGA-II for the case of large systems. However, this improvement comes at the expense of diversity of solutions in the fronts identified.
Organic characterisation tools for distribution system management
Authors: Chow C. W. K. , Kuntke Philipp , Fabris Rolando , Drikas Mary
Published: March 2009

In this investigation, high-performance size exclusion chromatography (HPSEC) was used to characterise organic matter in treated drinking water at key sampling locations along two selected distribution systems (chlorinated and chloraminated). Other water quality parameters such as colour, UV254, dissolved organic carbon (DOC) and assimilable organic carbon (AOC) as measured by bacterial regrowth potential (BRP), were also determined. One of the aims of this work was to develop new tools to monitor organic character change along the distribution system in order to identify impacting factors and develop management strategies based on water quality change. This study used samples from two contrasting distribution systems with different disinfection regimes and organic characteristics together with samples generated from laboratory simulations. System 1 is a chlorinated distribution system and generally requires elevated chlorine dosage to meet the demand due to the high DOC level. System 2 is a chloraminated system with stable water quality, low DOC and low chloramine dose (mild oxidation). Molecular size distribution determination using HPSEC is a very informative technique in assessing treatment processes and in this study the appearance of a molecular peak at 1,700 Da that can be used as an indicator of biological activity in distribution systems was confirmed. The use of BRP values, for upstream and downstream samples in the distribution system, was found to be a good approach to assess biological impacts on water stability. The observed biological impact from the biofilms between the studied systems were particularly useful in confirming the organic characterisation results.
Prediction of watermain failure frequencies using multiple and Poisson regression
Authors: Asnaashari A. , McBean E. A. , Shahrour I. , Gharabaghi B.
Published: March 2009

An important concern for water utilities managers is the prediction of failure frequency of watermains. To provide insight, reliance can be structured based upon modeling of historical data. In this research two regression-based models are employed, namely multiple and Poisson regression models. The models are derived based on 10 years of historical data collected for the city of Sanandaj in Iran. Several tests to validate each of the models are described. The comparison of correlation coefficients for multiple and Poisson models, besides violating initial assumptions, show that multiple regression-based modeling is inadequate.
Adsorption kinetics and isotherm characteristics of selected endocrine disrupting compounds on activated carbon in natural waters
Authors: Assoumani A. , Favier-Teodorescu L. , Wolbert D.
Published: March 2009

Bisphenol A (BPA) and ethynylestradiol (EE2), two representative endocrine disrupting compounds (EDCs), were tested for their adsorbabilities onto two powdered activated carbons (PACs). The main aim of the study was to create a prediction tool for the determination of the EDCs adsorbabilities at low ng.L−1 level. Single solute solution adsorption isotherms at high concentrations, for prediction purposes, and low concentrations, for verification of the prediction, were performed for one EDC/PAC couple. Over the whole range of concentration, results showed that the Langmuir-Freundlich model better suits the adsorption phenomenon than the Freundlich or Langmuir model. Kinetics experiments were carried out on the same EDC/PAC couple. HSDM modelling of single solute adsorption kinetics at high concentration allowed determining the kinetic coefficients kf and Ds; both were shown to dominate the mass transfer mechanism. Competitive adsorption isotherms at high and low concentrations showed that downward extrapolation of low concentration adsorption capacities from solely high concentration information results in acceptable error compared to the total range isotherm. The IAST-EBC approach combined with the Langmuir-Freundlich single solute model, for the target compound, and the Langmuir model, for the EBC, appears as an acceptable global model.
Natural organic matter removal by coagulation: effect of kinetics and hydraulic power
Authors: Yan Mingquan , Liu Hailong , Wang Dongsheng , Ni Jinren , Qu Jiuhui
Published: March 2009

In this paper, the mechanism of NOM removal by coagulation is investigated using coagulant polyaluminium chloride (PACl), compared with AlCl3. The kinetics of Al ion hydrolysis, interaction of hydrolyzed species of Al and NOM, and hydraulic power condition in coagulation process are investigated by programmable jar test, photometric dispersion analyzer and ferron assaying. After the coagulant dosing, Al ion would hydrolyze very quickly, and then monomeric Al and small polymeric Al would further hydrolyze to form larger polymer and precipitate, based on pH condition, while the further hydrolyzed process is relative slow. Although complexation between NOM and Al appears to be several orders of magnitude slower than hydrolysis of monomeric forms of Al, it would be faster than further polymerization and precipitation of Al during aging. However the further polymerization of fresh Al would benefit to Al-NOM complex aggregation and settlement. Therefore, PACl, with stabile preformed polymer shows significantly different performance in NOM removal compared with AlCl3. Although the hydraulic power condition plays significant role in collision frequency and efficiency of particles removal, the process of the aggregation to form larger floc to settle down is relative slower than interaction of Al and NOM, and it is not very correlative to the performance of NOM removal if only it can provide enough mixture.
Combination of nano TiO2 photocatalytic oxidation with microfiltration (MF) for natural organic matter removal
Authors: Bai Hongwei , Zhang Xiwang , Pan Jiahong , Sun Darren D , Shao Jiahui
Published: March 2009

TiO2 photocatalytic oxidation was combined with microfiltration (MF) (PCOMF) to remove humic acid (HA) in waters through investigating the flux performance, TOC, UV254 and UV436 removal efficiency, the fouled membrane surfaces by SEM. The results demonstrated that the combined PCOMF process showed a high removal efficiency of UV254 and UV436 of HA (close to 100%). The removal efficiency of TOC was about 84.34% indicating that most of HA was mineralized into water and carbon. The SEM images witnessed that the fouling on the membrane surfaces contaminated by PCO effluents after UV254 and UV365 light irradiation was mainly attributed to cake layer, which was reversible due to the increase of aggregated particles size consisting of HA and TiO2. Eventually, the combined PCOMF process displayed an improved effect on HA removal and fouling control to a certain level.
Understanding and forecasting taste-and-odour formation in a drinking water distribution system: case study of Lyon (France)
Authors: Corbi Elise , Jacquemet Valérie , Quendo Alain , Manciot Francine , Lamy Adeline , Texier Franck
Published: March 2009

Lyon, France has the opportunity to distribute in abundance a groundwater resource with a good quality for drinking water. However, the length and the complexity of the distribution network can lead to consumer complaints in some areas of the water distribution system. In order to improve the organoleptic quality of distributed water, the water supplier wants to get a better understanding of potential taste and odour formation and to succeed in controlling it. Since 2006, activities have been taken with targeted analyses and sensory evaluation of water, taking into account both the consumers' private networks and the citywide distribution network. The first results were focused on the occurrence of bromophenols along the water distribution system, the understanding of the mechanisms of formation of such compounds, as well as their incidence on taste-and-odour events at the consumer's home.
Superstability of adjointable mappings on Hilbert c∗-modules
Authors: Frank M. , Găvruţa P. , Moslehian M.S.
Published: March 2009

We define the notion of ?-perturbation of a densely defined adjointable mapping and prove that any such mapping f between Hilbert A-modules over a fixed C*-algebra A with densely defined corresponding mapping g is A-linear and adjointable in the classical sense with adjoint g. If both f and g are every- where defined then they are bounded. Our work concerns with the concept of Hyers-Ulam-Rassias stability originated from the Th. M. Rassias' stability theorem that appeared in his paper [On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc., 72 (1978), 297-300]. We also indicate complementary results in the case where the Hilbert C?-modules admit non-adjointable C*-linear mappings.
Transient limits
Authors: Richman Fred , Winkowska-Nowak Katarzyna
Published: March 2009

Let A be a Markov matrix depending on a small parameter ?, and Cn the average of the first n powers of A. The stationary distributions of A are the rows of S = lim n?+? Cn. The limiting stationary distributions are the rows of lim ??0 S. We investigate transient limits of the sequence Cn. These idempotent Markov matrices come up implicitly in an algorithm to compute limiting stationary distributions. They represent the intermediate-term behavior of the Markov chain at different time scales.
A combinatorial identity for a problem in asymptotic statistics
Authors: Albrecher Hansjörg , Teugels Jozef , Scheicher Klaus
Published: March 2009

Let (Xi)i?1 be a sequence of positive independent identically distributed random variables with regularly varying distribution tail of index 0 < ? < 1 and define Tn = X1?+X2?+???+Xn?/(X1+X2+???+ Xn)?.In this note we simplify an expression for lim n?? E(T kn ), which was obtained by Albrecher and Teugels: Asymptotic analysis of a measure of variation. Theory Prob. Math. Stat., 74 (2006), 1-9, in terms of coefficients of a continued fraction expansion. The new formula establishes an unexpected link to an enumeration problem for rooted maps on orientable surfaces that was studied in Arqu?s and B?raud: Rooted maps of orientable surfaces, Riccati's equation and continued fractions. Discrete Mathematics, 215 (2000), 1-12.
Zero and coefficient inequalities for stable polynomials
Authors: Rubió-Massegú J. , Díaz-Barrero J.L.
Published: March 2009

In this paper an elementary inequality and Cardan-Vi?te formulae are used to obtain some inequalities involving the zeros and coefficients of stable polynomials with complex coefficients.
On conformally invariant extremal problems
Authors: Manojlovic Vesna
Published: March 2009

This paper deals with conformal invariants in the euclidean space Rn, n ? 2, and their interrelation. In particular, conformally invariant metrics and balls of the respective metric spaces are studied.
Characteristic, admittance and matching polynomials of an antiregular graph
Authors: Munarini Emanuele
Published: March 2009

An antiregular graph is a simple graph with the maximum number of vertices with different degrees. In this paper we study the characteristic polynomial, the admittance (or Laplacian) polynomial and the matching polynomial of a connected antiregular graph. For these polynomials we obtain recurrences and explicit formulas. We also obtain some spectral properties. In particular, we prove an interlacing property for the eigenvalues and we give some bounds for the energy.
ESI-MS spectra of 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones
Authors: Marinkovic Aleksandar , Vasiljevic Tatjana , Lausevic Mila , Jovanovic Bratislav
Published: March 2009

Twelve 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones were investigated by tandem mass spectrometry using positive as well as negative electrospray ionization. The influence of the electron affinity of the substituent and the steric effect on the fragmentation is discussed. Pyridinones with a substituent of low proton affinity show loss of water, HCN or benzene from the pyridinone ring in the first step of MS2 fragmentations. Oppositely, if a substituent with high proton affinity is present on the phenyl ring in the 4-position of pyridinone, the fragmentation paths are complex, depending mainly on the substituent proton acceptor ability. Elimination of neutral molecules CO, HCN, H2O, PhH (benzene) or Ph and CN radicals are fragmentation processes common for all compounds in the subsequent steps of the fragmentations.
Acid-base equilibria of the Zn(II) and Fe(III) complexes with condensation products of 2-acetylpyridine and the dihydrazide of oxalic and malonic acid
Authors: Drazic Branka , Popovic Gordana , Jelic Ratomir , Sladic Dusan , Mitic Dragana , Andjelkovic Katarina , Tesic Zivoslav
Published: March 2009

Acid-base equilibria of Zn(II) and Fe(III) complexes with N',N'2-bis- [(1E)-1-(2-pyridyl)ethylidene]ethanedihydrazide (ligand L1) and N',N'2-bis[(1E)- -1-(2-pyridyl)ethylidene]propanedihydrazide (ligand L2), i.e., [Fe(L1)Cl2(H2O)], [Fe(L2)Cl(H2O)]2+, [Zn(L1)(H2O)3]+ and [Zn(L2)(H2O)2]2+, which expressed cytotoxic activity, were investigated in aqueous media. The equilibrium constants were determined potentiometrically at 25?C at a constant ionic strength of 0.10 mol/dm3 (Na2SO4). The results showed that at pH < 8 both the Fe(III) complexes studied here have three, while [Zn(L1)(H2O)3]+ and [Zn(L2)(H2O)2]2+ have one and two titratable protons, respectively. Based on the obtained values for the equilibrium constants, protonation schemes of the examined complexes are proposed.
Effect of non-stationary current regimes on the morphology of silver electrodeposits
Authors: Dimitrov Aleksandar , Paunovic Perica , Popovski Orce , Slavkov Dragan , Kamberovic Zeljko , Hadzi-Jordanov Svetomir
Published: March 2009

This work is concerned with the use of reverse current regimes in order to form small-grained and compact silver deposits during the electrorefining process. Several parameters were varied, i.e., i) anodic overpotential, ii) cathodic vs. anodic time ratio and iii) duration of the anodic pulse. After optimization of these parameters, phosphate ions were added and the electrolyte was stirred. The effects of a rise of the anodic overpotential on the grain sizes of the silver deposit and compactness were studied. Prolongation of the anodic time had a similar influence but with a decrease in current efficiency. An increase of the cathodic vs. anodic time ratio caused an enlargement of the grains and a decrease in the compactness of the deposit. Optimal morphological characteristics were obtained when PO3-4 were added and the electrolyte was stirred.
The effect of the concentration of the reacting ion on the control of the electrodeposition process
Authors: Zivkovic Predrag , Nikolic Nebojsa , Gvozdenovic Milica , Popov Konstantin
Published: March 2009

The effect of the concentration of the reacting ion on the nature of the control of the electrodeposition process was investigated by digital simulation of the polarization curve using the Newman form of the polarization curve equation and the Levich dependence of the limiting diffusion current density under natural convection conditions. A simple method for the determination of the exchange current density from polarization measurements is also proposed. The agreement with experiments was correct.
A study of the antibacterial efficiency and coloration of dyed polyamide and polyester fabrics modified with colloidal Ag nanoparticles
Authors: Ilic Vesna , Saponjic Zoran , Vodnik Vesna , Mihailovic Darka , Jovancic Petar , Nedeljkovic Jovan , Radetic Maja
Published: March 2009

In this study, the influence of dyeing on the antibacterial efficiency of polyamide and polyester fabrics loaded with colloidal Ag nanoparticles and the influence of the presence of Ag nanoparticles on the color change of dyed fabrics were investigated. Dyes C.I. acid green 25 and C.I. disperse blue 3 were used for dyeing of polyamide fabrics, while dye C.I. disperse violet 8 was used for dyeing of polyester fabrics. The influence of Ag nanoparticles on the color change of polyamide fabrics depends on the dye type, but generally it was lower compared to polyester fabrics. Polyester fabrics exhibited excellent antibacterial efficiency against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli, independent of the order of dyeing and Ag loading. Polyamide fabrics provided a desirable level of antibacterial activity only if the Ag loading was performed after dyeing.
Analytical approximate solutions for two-dimensional viscous flow through expanding or contracting gaps with permeable walls
Authors: Dinarvand Saeed , Rashidi Mohammad , Doosthoseini Ahmad
Published: March 2009

In this paper, the problem of laminar, isothermal, incompressible and viscous flow in a rectangular domain bounded by two moving porous walls, which enable the fluid to enter or exit during successive expansions or contractions is solved analytically by using the homotopy analysis method (HAM). Graphical results are presented to investigate the influence of the nondimensional wall dilation rate α and permeation Reynolds number Re on the velocity, normal pressure distribution and wall shear stress. The obtained solutions, in comparison with the numerical solutions, demonstrate remarkable accuracy. The present problem for slowly expanding or contracting walls with weak permeability is a simple model for the transport of biological fluids through contracting or expanding vessels.
Acoustic spectroscopy and electrical characterization of SiO2/Si structures with ultrathin SiO2 layers formed by nitric acid oxidation
Authors: Bury Peter , Kobayashi Hikaru , Takahashi Masao , Imamura Kentaro , Sidor Peter , ÄŒernobila FrantiÅ¡ek
Published: March 2009

Ultrathin silicon dioxide (SiO2) layers formed on Si substrate with nitric acid have been investigated using both acoustic deep-level transient spectroscopy (A-DLTS) and electrical methods to characterize the interface states. The set of SiO2/Si structures formed in different conditions (reaction time, concentrations of nitric acid (HNO3), and SiO2 thickness [3â€“9 nm]) was prepared. The leakage current density was decreased by post-oxidation annealing (POA) treatment at 250Â°C in pure nitrogen for 1 h and/or post-metallization annealing (PMA) treatment at 250Â°C in a hydrogen atmosphere for 1 h. All structures of the set, except electrical investigation, current-voltage (I - V), and capacitance â€” voltage (C - V) measurements, were investigated using A-DLTS to find both the interface states distribution and the role of POA and/or PMA treatment on the interface-state occurrence and distribution. The evident decreases of interface states and shift of their activation energies in the structures with PMA treatment in comparison with POA treatment were observed in most of the investigated structures. The results are analyzed and discussed.
Ytterbium doped phosphate glass photonic crystal fiber laser
Authors: Franczyk M. , Stępień R. , Pysz D. , Kujawa I. , Buczyński R. , Jabczyński J.
Published: March 2009

We demonstrate the 3% mol ytterbium doped phosphate glass air-clad photonic crystal fibre (PCF) laser of 43-cm length in single-mode operation. The fabrication and testing of the laser is introduced. The laser has the diameter of the core of 12 µm created in photonic microstructure and generates at wavelength of 1030 nm. Near 4-W output power and 14.6% slope efficiency against the launched pump power is demonstrated in preliminary characterization. The difference of refractive indices achieved in doped and undoped glass is Δn = 0.0004. We used the doped glass with the negative core-cladding Δn to assure the photonic crystal fibre way of single-mode propagation.
Liquid-crystalline properties of 4-alkyl-, 4-alkyloxy and 4-halogene-4′-hydroxyazobenzene alkyloates
Authors: Trzaska J. , Galewski Z.
Published: March 2009

Twenty one esters, 4-alkyl-, 4-alkyloxy-, 4-nitro- and 4-halogene-4′-hydroxyazobenzne alkyloates have been synthesised. Basing on the DSC calorimetry and polarizing microscopy liquid- crystalline polymorphism was investigated. Five types of mesophases were identified: nematic, smectics A, C, F and unknown X (probably G).
Effects of fields and anchoring on biaxial nematic ordering
Authors: Yasen M. , Torikai M. , Yamashita M.
Published: March 2009

Symmetry of a nematic liquid crystal phase is broken by an anchoring wall and also by an external field. Nematic system sandwiched between biaxial anchoring walls is introduced as a correspondent to a bulk nematic system exposed to a couple of fields, an electric field and a magnetic one in directions perpendicular to each other, and thermal behaviours of the system are studied. The crossover between a homeotropic structure and homogeneous one occurs, similarly to the bulk system in the fields, in which the anchoring condition of coexistence is shown to have the same expression as the one at the bulk. As to a characteristic phenomenon at the sandwiched system, it is proved that an appearance of a biaxial nematic order suppresses a uniaxial nematic order. A surface transition, i.e., a wetting phenomenon is shown to occur also in the biaxial nematics, even though the uniaxial order is suppressed therein.
Effect of bias in ferroelectric-antiferroelectric relaxation
Authors: Geday M. , Medialdea D. , Cerrolaza B. , Bennis N. , Quintana X. , Otón J.
Published: March 2009

The ferroelectric-antiferroelectric transition in greyscale generation of antiferroelectric liquid crystal displays (AFLC) is a heterogeneous process. The process has been described as the growth of finger-like domains [1]. We have previously studied the ferroelectric-antiferroelectric phase transition, relaxation that follows the data pulse in surface stabilized asymmetric antiferroelectric liquid crystal displays using biasless video frequency waveforms [2]. This relaxation involves an intensity decay of the light transmitted by a pixel and depends on several parameters such as surface stabilization, rotational viscosity of the AFLC, magnitude of the data pulse, and bias voltage.

The usual multiplexed driving of AFLC displays leads to long-term stabilisation of the grey levels induced by the data pulses within the selection time. However, depending on the bias level, alternative greyscale mechanisms may be obtained by allowing the grey levels to decay during the frametime. These greyscales may be advantageous in some instances since they improve the dynamic response of the AFLC device and reduce the reset time of the waveform.

In this study we extend the previous work to include the effect of bias. We present the measured data, in terms of growth pattern and speed and present an extension of the previously model on order to explain the results.
Formulation development of oral controlled release tablets of hydralazine: Optimization of drug release and bioadhesive characteristics
Authors: Singh Bhupinder , Pahuja Sonia , Kapil Rishi , Ahuja Naveen
Published: March 2009

Formulation development of oral controlled release tablets of hydralazine: Optimization of drug release and bioadhesive characteristics

The current study involves development of oral bioadhesive hydrophilic matrices of hydralazine hydrochloride, and optimization of theirin vitrodrug release profile andex vivobioadhesion against porcine gastric mucosa. A 32central composite design was employed to systematically optimize the drug delivery formulations containing two polymers,viz., carbomer and hydroxypropyl methyl cellulose. Response surface plots were drawn and optimum formulations were selected by brute force searches. Validation of the formulation optimization study indicated a very high degree of prognostic ability. The study successfully undertook the development of an optimized once-a-day formulation of hydralazine with excellent bioadhesive and controlled release characteristics.
Frequency Selective Control of a Parallel Active Filter with Resonance Filter Regulators
Authors: Krievs O. , Ribickis L.
Published: March 2009

Frequency Selective Control of a Parallel Active Filter with Resonance Filter Regulators

The paper describes a method for frequency selective control of parallel active filters that are applied for compensation of the current harmonic distortions and the displacement power factor in symmetrical three-phase systems with a known harmonic spectrum. For simulation, an active filter for harmonic current compensation of a three-phase full-bridge diode rectifier was used. Comparative analysis has shown a good agreement between the results obtained experimentally and by simulation
Estimation of the Energy Security Level and Definition of the Criteria for Damage Forecasts
Authors: Molochko F. , Molochko A. , Ekmanis J. , Zeltins N. , Zebergs V.
Published: March 2009

Estimation of the Energy Security Level and Definition of the Criteria for Damage Forecasts

In the work, the energy security indicators in a region (a state) are considered, and two general directions are proposed for search among the criteria for estimation and forecast of the damage inflicted by power supply limitations: based on the differentiated calculations for each economic subject, and on the generalised indices of regional economy. Of especial interest is analysis of a recently introduced damage intensity factor and its dependence on the level of limitations and the type of energy carriers.
Cytological Studies of Nymphaea Species available in Bangladesh
Authors: Hossain A , Kabir G , Ud-deen MM , Alam AMS
Published: March 2009

The present investigation was undertaken in order to study the somatic karyotypes of four species of Nymphaea available in Bangladesh. Karyotypes of four species of Nymphaea revealed that most of the chromosomes were metacentric indicating their primitive nature and chromosome counts revealed a polyploid series of tetraploid, pentaploid and hexaploid based on X=14. Findings of the present study indicated that Nymphaea pubescens is a hexaploid (6X=84, white flower) which might have originated by chromosome doubling of Nymphaea daubeniana (3X=42) while Nymphaea rubra and Nymphaea nouchali (Type-1) are tetraploid (4X=56) species. Key words: Nymphaea, karyotype Â  doi: 10.3329/jbs.v15i0.2197 J. bio-sci. 15: 7-13, 2007 Â
Impacts of Food Diversity on some Reproductive Attributes in the Gray Field Slug Deroceras reticulatum (MÃ¼ller)
Authors: Islam M Saiful
Published: March 2009

Using a food choice design consisting of a single, double and multiple diets, impacts of three common vegetables viz. cabbage (CAB), lettuce (LET) and potato (POT) on some important reproductive attributes of the gray field slug Deroceras reticulatum (MÃ¼ller) have been assessed. Although adult body weight was not affected by the diets, brood size was maximum in a double diet (CAB+POT), but multiple diets (CAB+LET+POT) did not enhance egg productivity. Both LET and POT had induced significantly greater number of eggs per day in comparison with CAB. Multiple diets resulted in significantly heavier eggs than the eggs from single or double diet regimes. Eggs laid on LET had the lowest and that on CAB+LET+POT had the highest developmental time but the hatch rate across the diet regimes did not differ significantly. Hatchlings from the single diet treatment were heavier than the double diet regime, but those between single vs. multiple or double vs. multiple diets did not vary statistically. The heaviest hatchlings were from LET and the lightest ones were from the CAB+LET treatments. The present results would help researchers in selecting a convenient culture medium for rearing experimental slugs in the laboratory. In addition, the data suggest that polyculture of vegetables might reduce slug damage, especially by reducing the brood size, egg production and hatchling size of D. reticulatum in the fields. Key words: Deroceras, field slug, food diversity, reproductive attributes, alternative food source Â  doi: 10.3329/jbs.v15i0.2198 J. bio-sci. 15: 15-21, 2007
Effect of Furadan on the Growth and Nitrogen Fixation by Blue Green Algae
Authors: Islam MZ , Begum S , Ara H , Waliullah TM
Published: March 2009

The study was carried out to determine the effects of pesticide on the growth and nitrogen fixation by blue green algae (BGA) that isolated from three different soils of Bangladesh viz., saline soil, calcareous soil and red soil. Furadan 5G, one of the most commonly used pesticides was selected for the study of eighteen taxa of blue green algae (BGA) which brought under the unialgal culture in the selected soil types. Variations observed in growth and nitrogen fixation among the isolates of a particular type of soil. The culture resulted as BGA grow slow under heterotrophically grown cultures than that of autotrophically grown cultures. On the other hand, nitrogen fixation in heterotrophically grown cultures was observed at higher rate. However satisfactory result was observed in both cases when field dose of Furadan was applied practically. In this case, heterotrophically grown cultures were more tolerant to pesticides with respect to growth and nitrogen fixation. Key words: Blue green algae, Furadan, nitrogen fixation, heterotrophic growth, autotrophic growth. Â  doi: 10.3329/jbs.v15i0.2199 J. bio-sci. 15: 23-34, 2007
Photoautotrophic and Photomixotrophic Micropropagation of Three Potato Cultivars
Authors: Rahman MH , Alsadon AA
Published: March 2009

The present study was aimed to compare the photoautotrophic (PAM) and photomixotrophic micropropagation (PMM) of three potato cultivars (Hermes, Rosetta and Asterix). Cultures were initiated from single node explants and established in MS basal medium with some modifications. Potato plantlets responded in sugar-free media although sugar-containing media (PMM1 and PMM2) performed better as compared to that of sugar-free (PAM1 and PAM2) media. The PMM1 produced shoot length averaging 6.25 cm with 8.08 nodes and weighing 0.24 g fresh weight of plantlet. On the other hand, PAM1 grown culture produced 4.03 cm shoot length, 8 nodes and 0.06 g of fresh weight. Shoot length and fresh weight of plantlets were significantly higher in PMM1 and PMM2 based media. Whereas the number of nodes per shoot was not significantly different on media with or without sugar (except the media PAM2). Sugar and vitamin-free media ( PAM2 ) performed inferior in all the traits. Key words: Potato, Photoautotrophic and Photomixotrophic Micropropagation. Â  doi: 10.3329/jbs.v15i0.2210 Â  J. bio-sci. 15: 111-116, 2007
Physico-Chemical and Nutritional Studies of Terminalia belerica Roxb. Seed Oil and Seed Kernel
Authors: Molla Md Tamzid Hossain , Alam MT , Islam M A-U
Published: March 2009

Oil was extracted from Terminalia belerica Roxb. seed kernel by solvent extraction process. The whole seed contained 12.28 % oil on dry basis. The physico-chemical properties of the oil were determined. Moisture, ash and crude fibre contents of the seed kernel were found to be 8. 43, 2.54, and 8.78% respectively. The refractive index, co-efficient of viscosity, specific gravity, and energy of activation of the oil were found to be 1.28, 403.6 millipoise at 30Â°C, 0.93 and 6.97 k.cal/mole respectively. The oil was found to be non-drying. Iodine value, acid value, peroxide value, saponification value, saponification equivalent, ester value, unsaponifiable matter, acetyl value, Reichert-Meissel value, Polenske value, free fatty acids as oleic acid and cholesterol content of the oil were recorded as 107, 3.69, 3.14, 189.24, 296.44, 185.55, 1.24%, 3.78, 0.719, 0.945, 0.87% and 26.59 mg per 100 g oil, respectively. The oil was qualitative and quantitative analysed for fatty acid composition by TLC and GLC. The results showed that the fatty acids of the oil had chain length between C14 to C22. The oil contained 17.70% myristic acid, 21.6% palmitic acid, 45.67% oleic acid and 14.93% stearic acid. The whole kernel was analyzed for some nutrients and minerals. The kernel contained 22.57 and 8.38% total lipid and protein respectively. It also contained 0.19mg, 0.45mg, 0.79g and 1.1mg of vitamin B1, B2, C and A respectively per 100g of kernel. Ca, Mg, K, Na, P, Fe, Mn, Zn and Cu were found to be 0.3, 0.02, 0.2, 0.2, 0.01%; 23, 1, 12 and 12 ppm respectively in kernel and 0.12, 0.05, 1.15, 0.18, 0.45%; 204, 4, 54 and 50 ppm respectively in oil. Key words: T. belerica seed oil and kernel, physico-chemical behaviour, micronutrients, fatty acid profile, GLC. Â  doi: 10.3329/jbs.v15i0.2211 Â  J. bio-sci. 15: 117-126, 2007
A comparative study of oak (Quercus, Fagaceae) seedling physiology during summer drought in southern California
Authors: Mahall Bruce E. , Tyler Claudia M. , Cole E. Shelly , Mata Catarina
Published: March 2009

Natural recruitment of oaks appears to be declining throughout the northern hemisphere. Summer drought poses a potentially important barrier to oak recruitment in southern California. To evaluate this barrier, we grew evergreen Quercus agrifolia and deciduous Q. lobata from seeds near parental trees. We measured water relations, chlorophyll fluorescence, and gas exchange during these seedlings’ fourth and fifth summers and compared them to neighboring adults. Most seedlings had substantially lower values for predawn xylem pressure potential (Ψpd), minimum photosystem II (PSII) quantum efficiency (ΦPSIIMIN), maximum quantum efficiency for PSII under dark‐adapted leaf conditions (Fv/Fm), and maximum photosynthetic assimilation (Amax), and higher values for maximum nonphotochemical quenching (NPQmax) than did conspecific adults. The high, unvarying Ψpd values of the adults suggest they use perennially available groundwater. Quercus lobata seedlings commonly had lower values for Ψpd than did Q. agrifolia, and values for Ψpd and ΦPSIIMIN were significantly related to size in Q. lobata but not in Q. agrifolia. These data suggest important interspecific differences in root architecture. Lower values for ΦPSIIMIN, Fv/Fm, and higher NPQmax in Q. agrifolia indicate that Q. agrifolia seedlings were usually under more stress than Q. lobata, which typically had higher Amax rates than did Q. agrifolia seedlings. Diurnal photosynthesis curves were quite flat for Q. agrifolia, but they peaked in the morning for Q. lobata. Established seedlings appeared to be under more stress than adults, but this stress did not appear severe enough to cause death. Access to perennially available groundwater may be crucial for the seedling to sapling transition.
Le sexisme au programme ?
Authors: Brugeilles Carole , Cromer Sylvie , Panissal Nathalie
Published: March 2009

Résumé En 2002, l’Éducation nationale française incluait, dans les programmes de l’école primaire, une liste de référence de 180 œuvres de littérature de jeunesse à destination des élèves du cycle 3, l’objectif étant la construction d’une culture partagée. La littérature étant considérée comme une voie privilégiée pour comprendre le monde et transmettre des valeurs, il a semblé légitime d’interroger les représentations du masculin et du féminin véhiculées par des œuvres explicitement choisies pour leur fonction socialisatrice dans un contexte où depuis les années 1960 le ministère de l’Éducation nationale affiche sa volonté d’assurer la pleine égalité des chances entre les filles et les garçons et, notamment, souhaite lutter contre les stéréotypes de sexe. Nous avons utilisé une méthodologie reposant sur la sociologie des rapports sociaux de sexe et sur les représentations sociales, qui consiste à recueillir, grâce à un questionnaire, des informations dans le texte et dans l’image, sur tous les personnages, éléments clés de toute histoire. L’analyse révèle non seulement des déséquilibres numériques entre les personnages féminins et masculins, mais aussi une hiérarchisation et une ségrégation sociale. Les portraits dressés inscrivent les hommes principalement dans la sphère professionnelle et les femmes dans la sphère familiale.