bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of weather and fuel type on the fuel composition of the area burned by forest fires in Ontario, 1996–2006
Authors: Podur Justin J. , Martell David L.
Published: June 2009

Forest fires are influenced by weather, fuels, and topography, but the relative influence of these factors may vary in different forest types. Compositional analysis can be used to assess the relative importance of fuels and weather in the boreal forest. Do forest or wild land fires burn more flammable fuels preferentially or, because most large fires burn in extreme weather conditions, do fires burn fuels in the proportions they are available despite differences in flammability? In the Canadian boreal forest, aspen (Populus tremuloides) has been found to burn in less than the proportion in which it is available. We used the province of Ontario's Provincial Fuels Database and fire records provided by the Ontario Ministry of Natural Resources to compare the fuel composition of area burned by 594 large (>40 ha) fires that occurred in Ontario's boreal forest region, a study area some 430 000 km2 in size, between 1996 and 2006 with the fuel composition of the neighborhoods around the fires. We found that, over the range of fire weather conditions in which large fires burned and in a study area with 8% aspen, fires burn fuels in the proportions that they are available, results which are consistent with the dominance of weather in controlling large fires.
An evaluation of patch connectivity measures
Authors: Prugh Laura R.
Published: June 2009

Measuring connectivity is critical to the study of fragmented populations. The three most commonly used types of patch connectivity measures differ substantially in how they are calculated, but the performance of these measures has not been broadly assessed. Here I compare the ability of nearest neighbor (NN), buffer, and incidence function model (IFM) measures to predict the patch occupancy and colonization patterns of 24 invertebrate, reptile, and amphibian metapopulations. I predicted that NN measures, which have been criticized as being overly simplistic, would be the worst predictors of species occupancy and colonization. I also predicted that buffer measures, which sum the amount of habitat in a radius surrounding the focal patch, would have intermediate performance, and IFM measures, which take into account the areas and distances to all potential source patches, would perform best. As expected, the simplest NN measure (distance to the nearest habitat patch, NHi) was the poorest predictor of patch occupancy and colonization. Contrary to expectations, however, the next‐simplest NN measure (distance to the nearest occupied [source] patch, NSi) was as good a predictor of occupancy and colonization as the best‐performing buffer measure and the general IFM measure Si. In contrast to previous studies suggesting that area‐based connectivity measures perform better than distance‐based ones, my results indicate that the exclusion of vacant habitat patches from calculations is the key to improved measure performance. I highlight several problems with the parameterization and use of IFM measures and suggest that models based on NSi are equally powerful and more practical for many conservation applications.
Critical Conditions for Effective Sand-Sized Solids Transport in Horizontal and High-Angle Wells
Authors: Duan Mingqin , Miska Stefan , Yu Mengjao , Takach Nicholas , Ahmed Ramadan , Zettner Claudia
Published: June 2009

Effective removal of small, sand-sized solids is critical for successful drilling and completion operations in sand reservoirs. Recent experience in extended-reach drilling also indicates that inefficient transport of smaller cuttings is a main factor for excessive drag and torque. This study was undertaken to determine two critical conditions for efficient transport of small solids. The two conditions are represented by the critical resuspension velocity (CRV), the minimum fluid velocity necessary to initiate solids-bed erosion, and the critical deposition velocity (CDV), the minimum fluid velocity required to prevent bed formation.

Experiments were conducted in a field-scale flow loop (8 × 4.5 in., 100 ft long) to determine CRV and CDV for 0.45-mm and 1.4-mm sands in different fluids over a range of bed heights and hole inclinations. The results show that, depending on sand size and fluid properties, CDV is approximately two to three times larger than CRV. Water is more effective than low-concentration polymer solutions for bed erosion. However, polymer solutions are more helpful than water in preventing bed formation. This indicates the need for different drilling fluids for cleanout and drilling operations.

A mechanistic model was developed to predict CRV for a solids bed. Both experimental and theoretical results indicate the importance of interparticle forces that are incorporated into the model. The model accounts for drillpipe eccentricity in any direction in an annulus, which is consistent with experimental observations. The model predictions are in good agreement with experimental results. Existing CDV correlations developed for larger cuttings were verified by experimental data for sands. The differences are approximately 25%. Results in this study will be useful not only in drilling and completion through sand reservoirs, but also in extended-reach drilling and sand control.
Gauge, Cutting Structure, Torque Control Components—What Really Counts for Optimal Tool Face Control With FC Drill Bits?
Authors: Barton Steven , May Henry , Johnson Simon
Published: June 2009

Tool-face control is widely regarded as one of the greatest challenges when drilling directionally with an FC (fixed cutter) drill bit on a positive displacement motor (PDM).

Tool-face offset is proportional to the torque generated by the bit. FC bits, by nature, generate high levels of torque. If an external force acting on the bit causes an FC bit to over-engage, a large change in downhole torque is typically produced, which causes rotation of the drillstring and loss of tool-face orientation. It is therefore desirable for an FC bit to produce a torque response that does not vary greatly with changes in the external forces applied.

This paper examines the effect of varied components of an FC drill bit to determine the key design requirements to deliver a smooth torque response and improved directional performance. This includes evaluation of the results from a comprehensive series of laboratory tests to determine the effectiveness of a number of varied, removable torque controlling components (TCC). The goal was to establish a configuration that would provide predictable torque response to applied weight on bit (WOB), allowing cutting structures to be independently optimized for overall higher penetration rates.

A novel gauge geometry was engineered to reduce drag and deliver a smoother borehole. This would provide less torque when sliding and beneficial gauge pad interaction with the borehole when in rotating mode.

Field performance studies clearly demonstrate that matching TCC, an optimized cutting structure, and gauge geometry to a steerable assembly delivers smooth torque response and improved directional control. Benefits within rotary vertical applications are also demonstrated. Successful application has resulted in significant time and cost savings.
Implementation of a Shock and Vibration Mitigation Process: Achieving Real-Time Solutions and Savings
Authors: Akinniranye Goke , Megat Amanda , Elsweisy Hesham , Palacio Julio , Poedjono Benny , Goobie Roger
Published: June 2009

Worldwide, the costs associated with the exploration and production of oil have increased almost exponentially in the past 5 years. This sharp rise in daily costs has also led to a new urgency from operators to find more-reliable and -efficient ways of doing business.

Shock and vibration (S&V) are the leading causes of failure for measurement-while-drilling (MWD) and rotary-steerable systems today. These failures have a major impact on operators and service companies, costing millions of dollars in repairs and hours of rig time.

To better understand downhole dynamics, a wide variety of service companies now offer lateral, axial, and transverse-shock measurements, along with downhole rev/min (RPM) readings. In the best case, these measurements offer a reactive method of drilling, and in the worst case, they provide no help in solving the problem or in preventing damage to the bottomhole assembly (BHA).

For S&V measurements to be effective, operators and service companies must work together to create a comprehensive process that includes each phase of drilling—planning, execution, and evaluation. An S&V standard combined with increased client awareness and education has allowed a new level of success to be achieved at the rigsite. Now, S&V issues at the rig can be identified in real time and monitored remotely from an operations-support center. This communication structure, coupled with prejob planning and modeling and the capture of post-run lessons learned, can be used to offer solutions when problems arise, thereby preventing damage to the BHA, reducing rig non-productive time (NPT), and improving the rate of penetration (ROP).
A Compendium of Directional Calculations Based on the Minimum-Curvature Method—Part 2: Extension to Steering and Landing Applications
Authors: Sawaryn S. J. , Tulceanu M. A.
Published: June 2009

The point-to-target calculations contained in Part 1 of the compendium (Sawaryn and Thorogood 2005) were restricted to those cases in which the 3D target coordinates were stated explicitly. However, another class of problems exists where the target's structural position is determined indirectly from other constraints defining the arc's orientation. This new paper builds on the earlier work and contains complete details of twelve explicit algorithms, including the calculation of a target on the basis of the toolface at the start or end of an arc and for the landing of a well path parallel to a formation bedding plane.

These cases find practical application in computing trajectories of motor runs and in whipstock operations. The curvature of the trajectory landing on a bedding plane varies with direction and has a distinct minimum and maximum. These values may be used either to minimize the distance to the target or to limit the dogleg severity (DLS) to avoid drillpipe fatigue, a concern in short-radius drilling applications.

The algorithms add to the compendium and are useful extensions to the engineer's computational toolkit. The paper shows that the trajectories, computed using the minimum-curvature calculation, are contained within the geometric surfaces defined by a torus or cyclide. These geometries explain why the explicit solutions exist, opening up possibilities for obtaining solutions to the more-complex cases.
Experimental and Numerical Investigations of Borehole Ballooning in Rough Fractures
Authors: Ozdemirtas M. , Babadagli T. , Kuru E.
Published: June 2009

Borehole ballooning/breathing is a combined mud-loss/-gain event observed during drilling operations in naturally fractured formations. Factors controlling this phenomenon must be well understood to correctly interpret its symptoms observed during drilling to avoid mixing ballooning with other formation flow incidents that might lead to unwarranted well-control procedures.

A mathematical model defining the ballooning process was developed and solved numerically using finite-difference approximation. It was shown that fracture roughness and fracture deformation play a significant role in the flow of drilling fluid in and out of a single fracture. In this study, the focus was mainly on the effect of fracture roughness (characterized by the fractal dimension of the fracture surface) and fracture aperture.

The main goal of this work was to compare the numerical-model results with laboratory-scale experimental observations. Therefore, experiments were performed to study the mud-loss and -gain events in artificially fractured rock samples. Cylinders of Berea sandstone, Indiana limestone, and granite were used for the experiments (1-in. diameter, 3-in. length). Two different fracture types were used to analyze the effect of fracture-surface roughness on the flow of drilling fluid in and out of the fracture. To create smooth fracture surfaces, cores were cut precisely into two equal pieces using a blade. Alternatively, axial load was applied on the cylindrical rock samples until a longitudinal fracture with a rough surface was generated.

The results of experimental observations and numerical-model study on the importance of fracture roughness were provided. Situations where the degree of roughness becomes critical were identified.
"Don't Let the Temperature Log Fool You"—False Indications of Height Containment From Case Studies in a Tectonically Stressed Environment
Authors: Dozier George C.
Published: June 2009

Fracture-height prediction and evaluation is critical in understanding the effectiveness of a fracturing treatment. Volumetrically, fracturing must adhere to mass-balance equations. Therefore, prop-pant placed in the fracture must be accounted for in the creation of fracture height, width, and length. In many cases, excessive fracture height generation is at the expense of fracture-width and -length creation. As a result, in fracture treatments where excessive height growth is believed to have occurred, premature screenouts are usually the result of insufficient fracture width. This unfortunate circumstance creates an operational strain and productivity underperformance for wells.

Various methods have been used to evaluate fracture height before the fracture treatment. These methods can be as simple as height estimates based on sensitivity studies of fracture-height growth for different fluids, pumping rates, and other factors, using a derived rock-stress profile within a fracturing simulator, and as complex as the most robust methods of direct measurement, using passive seismic monitoring of fracture events during an injection test. As the industry comes closer to what is believed to be direct measurement of fracture height, the level of trust increases as well.

Both temperature logs and radioactive tracers have been used on a regular basis by the fracturing industry to evaluate fracture-height containment (or the lack thereof). However, the information from these tools may be quite misleading when planning a fracture treatment because of the inherent assumption made when analyzing the log data. The major assumption is of a vertical fracture propagating from the wellbore. Nevertheless, in a tectonically stressed environment, where the maximum principal stress is not always an overburden, the assumption of a vertical fracture may be incorrect. Where this is true, the indication of height control seen in these log types may be a mirage. This paper describes, through case studies, the unique problems of evaluating fracture height in tectonically stressed formations. Furthermore, it shows that while both temperature and tracer logs may add value to evaluating fracture effectiveness, their results should be validated by a thorough pressure analysis of the injection data. If this critical step is forgone, many assumptions of height control, as indicated by a temperature log alone, may in fact conceal an environment of excessive height growth and lead to premature screenouts.
The First Dual-Lateral Well Successfully Drilled Underbalanced in Libya
Authors: Safar Hussein , Azhary Sadek , Hijazi Ahmad , Qutob Hani , Chopty James
Published: June 2009

The B24 well in the Fidaa Field was the first dual-lateral, underbalanced horizontal well drilled in Libya and the second well of Zueitina Oil Company's (ZOC) underbalanced drilling (UBD) campaign.

The targeted hard dolomite reservoir, "Facha," is partly depleted after 23 years of production to a 7.2 lbm/gal equivalent mud weight. Nitrified diesel, a two-phase drilling fluid, was used to drill the reservoir section of the B24 well underbalanced to avoid circulation losses and formation damage. Real-time logging while drilling (LWD) was crucial for geosteering the well path in a complex reservoir structure, and real-time annular-pressure measurement also was necessary to ensure that the underbalanced condition was maintained throughout the entire UBD phase.

Two 6-in. horizontal drains were drilled successfully with 2,053- and 1,517-ft drain lengths. Integrated efforts of ZOC and service companies of various disciplines during planning and operation stages of the well led to the success of the project. No quality, health, safety, and environment (QHSE) incidents were reported, and the productivity of the well was enhanced significantly (Cade et al. 2003; Qutob 2004a).

The B24 well's production alone contributes more than 30% of the total Fidaa field production.
Qualitative Research by Denzin, N.K. and Lincoln, Y. 2005
Authors: Uprety Laya Prasad
Published: June 2009

doi: 10.3126/njqrm.v1i0.1976 Nepalese Journal of Qualitative Research Methods Vol.1 2007 pp.64-67
The high-temperature creep properties of materials processed using severe plastic deformation
Authors: Xu Cheng , Kawasaki Megumi , Langdon Terence G.
Published: June 2009

Processing through the application of severe plastic deformation (SPD) is now an accepted procedure for introducing very significant grain refinement into bulk solids. Typically, experiments show that the materials processed in this way have grain sizes in the submicrometer or even the nanometer range. This exceptional grain refinement provides an opportunity for conducting creep tests at elevated temperatures and examining the occurrence of creep flow through mechanisms where the creep rate varies inversely with the grain size. The present paper describes creep experiments conducted on two different representative materials subjected to SPD processing: high-purity aluminum and an aluminum 7034 alloy. The results demonstrate that the creep behavior depends critically upon the thermal stability of the ultrafine-grain microstructures.
The elastic–plastic transition in nanograined polycrystals
Authors: Saada Georges , Dirras Guy
Published: June 2009

This paper is devoted to the analysis of the specific constraints imposed on the mean free path, the nucleation and the multiplication rate of dislocations in strained polycrystals whose grain size is smaller than about 100 nanometres. It is demonstrated that the extent of the microdeformation stage, at the end of which the yield stress should be measured, is definitely larger than the generally accepted value of 0.2 % proof strain for average grain sizes smaller than 125 nanometres. This analysis is confirmed experimentally in two instances. Systematic experimental analysis of the elastic – plastic transition in these materials is a necessary requirement in order to obtain relevant values of the flow stress in these materials.
Effect of equal channel angular pressing on microstructure, texture, and high-cycle fatigue performance of wrought magnesium alloys
Authors: Müller Julia , Janeček Miloš , Yi Sangbong , Čížek Jakub , Wagner Lothar
Published: June 2009

The magnesium alloys AZ80 und ZK60 received from Dead Sea Magnesium in as-cast conditions were extruded at T = 350 °C using an extrusion ratio of ER = 22. The extruded bars were severely plastically deformed by equal channel angular pressing (ECAP). Multiple ECAP processing up to 8 passes was done. The ECAP-induced changes in grain size and grain size distribution were measured by transmission electron microscopy while changes in dislocation density and crystallographic textures were determined by positron annihilation spectroscopy and X-ray diffraction analysis, respectively. The strain induced by ECAP was found to influence the microstructural characteristics, in particular the grain size, the dislocation density, and the crystallographic texture, which in turn enhance (or deteriorate) the mechanical or fatigue response of both alloys.
Deformation behaviour of ultrafine-grained 7075 aluminium alloy
Authors: Lukáč Pavel , Turba Kryštof , Málek Přemysl , Cieslar Miroslav
Published: June 2009

Samples of a 7075 aluminium alloy were prepared by the equal-channel angular pressing (ECAP) technique. The channel had a 10 mm × 10 mm cross section and an angle of 90°. A total of six passes was performed using route BC. The ECAP processing was carried out at 120, 170, and 220 °C. The ECAP-processed samples with grain sizes between 300 and 2000 nm were machined to tensile specimens with their tensile axis parallel to the pressing direction. Uniaxial tensile tests were carried out using an INSTRON testing machine at temperatures between room temperature and 300 °C at a constant crosshead speed giving an initial strain rate of 10 – 3 s – 1. The maximum stress decreases with increasing testing temperature. The elongation to failure increases with increasing testing temperature. The values of the yield stress, the maximum stress (ultimate tensile stress), and the elongation to failure depend also on the ECAP processing conditions.
Recovery and recrystallization behavior of aluminum processed by extrusion-preceded equal channel angular pressing
Authors: Zi Aikaterini , Stulíková Ivana , Smola Bohumil , Riehemann Werner
Published: June 2009

High-purity aluminum was severely plastically deformed by miniaturized extrusion-preceded ECAP as well as by cold rolling. Isochronal and isothermal annealing was performed to investigate the recovery and recrystallization behavior by measuring the development of Vickers microhardness and electrical resistivity. Both processes were found to take place which was verified by TEM and EBSD observations. The onset and course of recovery and recrystallization in cold-rolled Al were postponed to higher temperatures and time due to the lower stored deformation energy. The activation energies for recovery and recrystallization estimated from the microhardness response to isothermal annealing match well those of relevant processes, namely those of thermally activated dislocation motion, pipe-, boundary-, and self-diffusion.
EBSD investigation of the grain boundary distributions in ultrafine-grained Cu and Cu–Zr polycrystals prepared by equal-channel angular pressing
Authors: Dopita Milan , Janeček Miloš , Rafaja David , Uhlíř Jaromír , Matěj Zdeněk , Kužel Radomír
Published: June 2009

Ultrafine-grained copper and cooper–zirconium polycrystals prepared by equal-channel angular pressing following the route Bc to various strain (1, 2, 4 and 8 passes) were investigated using electron back-scatter diffraction. Equal-channel angular pressing resulted in significant grain-size reduction. The original course-grained structure evolved from prolate bands of cells/subgrains enclosed by lamellar nonequilibrium grain boundaries (after the first two passes) towards an equiaxed homogeneous microstructure with equilibrium grain boundaries (after 8 passes). Significant changes in the volume fraction and the character of grain boundaries were observed both in Cu and in Cu – Zr alloy. Pronounced evolution of twin-related boundaries (3n grain boundaries) with strain (number of ECAP passes) was found in Cu while only a weak increase of 3 and 9 grain boundaries was observed in Cu – Zr alloys.
XRD profile analysis of ECAP Cu and Cu + Zr samples
Authors: Matěj Zdeněk , Kužel Radomír , Dopita Milan , Janeček Miloš , Čížek Jakub , Brunátová Tereza
Published: June 2009

Technical purity copper and copper with addition of 0.18 wt.% of zirconium samples processed by equal channel angular pressing with different number of passes were studied by X-ray line profile analysis. Dislocation-induced broadening is the dominant effect determining diffraction line shape. X-ray analysis reveals increasing mean dislocation density (∼1015 m – 2) with the number of ECAP passes. The character of the deformation field connected with the dislocation distribution is slightly different in pure copper than in copper with addition of zirconium and evolves significantly during 4 or 8 ECAP passes in the case of pure copper.
Effects of shot peening on internal friction in cp aluminum and aluminum alloy 6008
Authors: Flejszar Aneta , Ludian Tomasz , Mielczarek Agnieszka , Riehemann Werner , Wagner Lothar
Published: June 2009

The strain-amplitude-dependent damping of bending beams of aluminum alloy 6008 and CP aluminum was measured at room temperature after different heat treatments and after shot peening. Shot peening led to an increase of damping in almost the whole measured amplitude strain range from 10 – 6 to 10 – 3 for CP aluminum. Strong ageing effects at room temperature were observed immediately after the shot peening process, namely an increase of the amplitude dependent part and a decrease of the amplitude-independent part of damping. After about 2700 h, ageing of the samples had saturated. For aluminum alloy 6008 much smaller ageing effects were found being due to compensating effects like formation of Cottrell clouds, precipitation of G.P. – zones, and the reduction of foreign atoms in solid solution. The found amplitude-dependent damping can be explained by the reversible movement of dislocations between strong pinning points like, e. g., precipitates and weak pinning points like solid solute atoms as proposed by the dislocation damping theory of Granato and Lücke. Using this model the found ageing effects can be explained by the diffusion of solid solute atoms to the dislocations.
High-temperature creep properties of Fe–Al alloys modified by Zr
Authors: Karlík Miroslav , Kratochvíl Petr , Pešička Josef , Vlasák Tomáš
Published: June 2009

Two Fe – Al alloys with Zr additions were prepared by vacuum induction melting and rolling at 1200 °C: a disordered (ferrite – A2) and a D03-ordered one. The data are compared to a similar Fe3Al-based alloy with lower Zr content investigated earlier. Tensile and creep tests were performed at 600, 700, and 800 °C, where the disordered alloy maintains its A2 structure, and D03-ordered alloys are transformed to B2-ordered structure. Transmission electron microscopy of the alloys crept at 600 °C showed precipitation of fine particles on dislocations, subgrain boundaries and also in the matrix. Coarsening of these particles during creep at 800 °C takes place. The particles in Fe3Al-based alloys are identified mostly as zirconium carbides, whereas (Fe, Al)2Zr precipitates were observed in the ferritic alloy. The increase of Zr content from 0.25 to 0.6 at.% does not have a significant effect on the high temperature (HT) mechanical properties of the Fe3Al-type aluminide, because both alloys contain the same amount of carbon. In consequence no additional volume fraction of ZrC particles could be formed. The creep resistance of the ferritic alloy is considerably lower, but this material can easily be rolled to prepare sheets for HT corrosion protection.
High-pressure torsion deformation of a magnesium-based nanocomposite
Authors: Száraz Zoltán , Trojanová Zuzanka , Zehetbauer Michael
Published: June 2009

Discs of microcrystalline magnesium reinforced with Al2O3 nanoparticles were deformed by high-pressure torsion at room temperature. Hydrostatic pressures from 1 to about 4 GPa were used and discs were deformed from 0.5 up to 2 rotations. The in-situ flow stress curves were obtained and transformed into resolved shear stress/resolved shear strain curves. In-situ stress – strain curves indicate some softening effects, which probably arise from recrystallisation. The evolution of microstructure was observed with methods of light microscopy and transmission electron microscopy. Radial dependence of the microstructure was also monitored with microhardness measurements. The high-pressure torsion deformation also affects the distribution of the reinforcing particles in the hexagonal matrix.
Seroprevalence of Hepatitis C Virus in HIV/AIDS Patients in Jos, Nigeria
Authors: Nimzing Lohya , Busari Bisayo , Ladep Nimzing G
Published: June 2009

Introduction: Hepatitis C Virus (HCV) infection is a life threatening infection and is more serious in people living with HIV/AIDS (PLWHA). It leads to liver damage more quickly and may also affect the treatment of HIV infection. This study was aimed at determining the seroprevalence of HCV, possible risk factors for HCV infection and highlighting the importance of HCV screening in PLWHA in Jos, Nigeria. Materials and Methods: One hundred and eighty two blood samples were collected from confirmed HIVpositive patients attending clinics at the Faith Alive Hospital in Jos for the detection of anti-hepatitis C antibodies. An enzyme linked immunosorbent assay (ELISA), DIALABTM HCV Ab test kit (DIALAB GmbH, Australia) was used for the analysis. Results: Sixty one of the 182 samples tested positive giving a co-infection rate of 33.9%. Old age and low educational levels of the patients were found to be associated with HCV/HIV co-infection (P<0.05). However, the patient's occupation and marital status and the possible risk factors analyzed which included: histories of blood transfusion, sexually transmitted infection (STIs) apart from HIV, surgery, multiple sex partners and injecting drug use were not associated with HCV infection (P>0.05) for the subjects screened. Also, the CD4 cell count ranges of patients and the use of antiretroviral therapy were not associated with HCV infection (P>0.05). Conclusion: The high HCV/HIV co-infection rate observed indicates a possible increase in the development of chronic liver diseases and hepatocellular carcinoma in these patients. Therefore, increasing education on HCV infection and routine screening of HIV patients for anti-HCV antibodies is critical. Key words: Hepatitis C virus, people living with HIV/AIDS (PLWHA), anti-hepatitis C antibodies, chronic liver diseases, hepatocellular carcinoma.      doi: 10.3329/blj.v1i1.2622 Bangladesh Liver Journal Vol.1(1) 2009 p.28-33
Determination of the Volatile Composition of Rhodobryum giganteum (Schwaegr.) Par. (Bryaceae) Using Solid-phase Microextraction and Gas Chromatography/Mass Spectrometry (GC/MS)
Authors: Li Lin , Zhao Jiancheng
Published: June 2009

A total of 38 volatile components were identified in Rhodobryum giganteum (Schwaegr.) Par. collected from two different geographic regions by headspace solid-phase microextraction (HS-SPME), combined with gas chromatography/mass spectrometry (GC/MS). The volatile components included some aliphatic and aromatic aldehydes, monoterpene hydrocarbons and a sesquiterpene (α-farnesene), with 1-methoxy-2-propyl acetate and n-hexanal being found to be the most abundant volatile components. Analysis of the chemical constituents in the volatile oil of the two samples showed that ten compounds were shared.
Phenolics: From Chemistry to Biology
Authors: Pereira David M. , Valentão Patrícia , Pereira José A. , Andrade Paula B.
Published: June 2009

In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, will be discussed. In addition, the increasing interest in phenolics’ biological activities is covered, and several works addressing this matter are referred.
Examination of Imprinting Process with Molsidomine as a Template
Authors: Luliński Piotr , Maciejewska Dorota
Published: June 2009

Eight different functional monomers were used with ethylene glycol dimethacrylate as a cross-linker and molsidomine as a template to obtain molecularly imprinted polymers (MIPs). Non-covalent interactions between molsidomine and each functional monomer in DMSO prior to thermal bulk polymerization were utilized. On the basis of calculated imprinting factors, MIP prepared with N,N’-diallyltartaramide was chosen for further investigations. Examination of interactions in the prepolymerization complex between molsidomine and N,N’-diallyltartaramide was performed using the Job method. The absorbance of isomolar solutions reaching a maximum for the molar ratio of template to monomer equal to 1:4. Scatchard analysis was used for estimation of the dissociation constants and the maximum amounts of binding sites. The polymer based on N,N’-diallyltartaramide has two classes of heterogeneous binding sites characterized by two values of Kd and two Bmax: Kd(1) = 1.17 mM-1 and Bmax(1) = 0.8 μmol/mg for the higher affinity binding sites, and Kd(2) = 200 μM-1 and Bmax(2) = 2.05 μmol/mg for the lower affinity binding sites. Furthermore, effects of pH and organic solvent on binding properties of MIP and NIP were investigated, together with release of molsidomine from both MIP and NIP.
EVALUATING WORKING QUALITY OF TRACTORS BY THEIR HARMFUL IMPACT ON THE ENVIRONMENT/TRAKTORIŲ DARBO KOKYBĖS VERTINIMAS PAGAL JŲ ŽALINGĄ POVEIKĮ APLINKAI/ОЦЕНКА РАБОЧЕГО КАЧЕСТВА ТРАКТОРОВ ПО ИХ ВРЕДНОМУ ВЛИЯНИЮ НА ОКРУЖАЮЩУЮ СРЕДУ
Authors: Juostas Antanas , Janulevičius Algirdas
Published: June 2009

The paper presents tractor working data and their engine conditions from economical and ecological point of view. Overlooked results presented in literature have a straight relation with reduction of tractor fuel consumption and unfriendly impact on the environment. The results of measurements show that for investigation of tractor performance quality during its working life, information collected in its microprocessors can be used. Investigation results of engine speed and torque aspects of different Deutz Fahr Agrotron tractor models with different working output are presented in the paper. Investigation results show that a tractor on average worked from 37% to 52% of the total working hours at a high torque (>50% Mmax ) and at medium (1000–2000 rpm) and high (>2000 rpm) engine speed. The investigation results show that almost half of tractor working time is unreasonable. The paper presents big improvement possibilities for tractor operating technologies by using a wider range of engine power, decreasing fuel consumption and unfriendly impact on the environment. Santrauka Tirta traktorių degalų sąnaudų ir žalingo poveikio aplinkai mažinimo galimybės. Matavimų rezultatais pagrindžiama, kad traktorių darbo kokybei per eksploatavimo laikotarpį tirti galima naudoti jų mikroprocesoriuose sukauptą informaciją. Pateikiami įvairių modelių ir įvairaus išdirbio Deutz Fahr Agrotron traktorių darbo kokybės (variklio sūkių dažnio ir apkrovos aspektais) per eksploatavimo laikotarpį tyrimų rezultatai. Nustatyta, kad didele apkrova (>50 % Mmax) vidutiniais (1000–2000 min–1) ir dideliais (>2000 min–1) variklio sūkiais traktoriai vidutiniškai dirba 37–52 % eksploatacijos laikotarpio, ir apie pusę eksploatacijos trukmės traktorių darbas neracionalus. Daroma išvada, kad visą traktorių eksploatavimo laiką galima tobulinti technologijas, parenkant tinkamesnius variklių darbo režimus, mažinti degalų sąnaudas ir žalingą poveikį aplinkai. Резюме Целью исследований было уменьшение потребления горючего в тракторных двигателях и их вредного влияния на окружающую среду. Проанализированы качественные характеристики (обороты и нагрузка двигателя ) разных моделей тракторов фирмы Deutz Fahr Agrotron, с разной наработкой моточасов за весь период эксплуатации. Исследованиями выявлено, что время работы тракторов с большой нагрузкой (>50% Mmax) при средних (1000– 2000 мин–1) и больших (>2000 мин–1) оборотах двигателя составляет 37–52% всего периода эксплуатации. Около половины всего времени в период эксплуатации тракторы работают нерационально. Делается вывод, что в период эксплуатации тракторов существует возможность совершенствовать технологии, шире применять лучшие режимы работы двигателей, снижать потребление горючего и вредное влияние на окружающую среду.
HAZARD PROFILE IN MANUFACTURING: DETERMINATION OF RISK LEVELS TOWARDS ENHANCING THE WORKPLACE SAFETY/PAVOJAI PRAMONĖJE. RIZIKOS LYGIO NUSTATYMAS IR DARBO VIETŲ SAUGUMO DIDINIMAS/ ПРОФЕССИОНАЛЬНАЯ ОПАСНОСТЬ. ОПРЕДЕЛЕНИЕ УРОВНЯ РИСКА И УВЕЛИЧЕНИЕ БЕЗОПАСНОСТИ РАБОЧИХ МЕСТ
Authors: Reinhold Karin , Tint Piia
Published: June 2009

This study focuses on occupational hazards and the determination of risk levels derived from them. Indoor climate, noise, and dust are examined. An approach with numerical criteria is offered to assess these occupational hazards in manufacturing using a simple/flexible risk assessment method. Practical examples and the results of measurements of occupational hazards in five industries (mechanical, printing, wood, plastic and clothing industries) in Estonia are presented. Noise, as the most obvious health hazard, is analysed in depth, and the risk for noise‐induced hearing loss is estimated. The overall purpose of the paper is to draw attention to the importance of measurements of occupational hazards in industry and to act as a reminder of a number of issues of practical relevance to effective workplace risk assessment from which employees, employers, occupational hygienists and physicians as well as authorities can benefit today and in the future. Santrauka Analizuojami profesiniai pavojai, kuriems gresiant būtina nustatyti rizikos lygį. Tirtas darbo aplinkos mikroklimatas, apšvieta, triukšmas ir dulkėtumo lygis. Profesiniams pavojams gamyboje įvertinti siūlomas paprastas ir lankstus rizikos vertinimo metodas, pagrįstas skaitiniais kriterijais. Pateikiami penkių Estijos pramonės šakų (mašinų apdirbimo, spaudos, medienos, plastmasės ir tekstilės) tyrimo šiuo požiūriu rezultatai ir praktiniai pavyzdžiai. Kaip akivaizdžiausias pavojus sveikatai plačiai analizuojamas triukšmas, įvertinama klausos praradimo rizika. Straipsnio tikslas – atkreipti dėmesį, kaip svarbu pramonėje nustatyti profesinę riziką ir priminti apie kelis svarbius praktinius aspektus, kad darbo rizikos vertinimas būtų efektyvus ir padėtų darbuotojams, darbdaviams, darbo vietos higienos specialistams, gydytojams bei sprendimų priėmėjams. Резюме Проанализирована профессиональная опасность для здоровья людей, работающих на промышленных предприятиях, и определен уровень риска. Исследован микроклимат, освещение, уровень шума и пыльность на предприятиях. Для оценки профессионального риска для здоровья людей предложено применение простого (гибкого) метода, основанного на численных критериях. Исследованы пять отраслей промышленности Эстонии (машиностроительная, печатная, деревообрабатывающая, пластмассовая и текстильная), приведены результаты и практические примеры. Наиболее широко исследовано воздействие шума на здоровье людей, оценен риск потери слуха из-за шума. Целью статьи было обратить внимание на необходимость оценки профессионального риска на промышленных предприятиях, выявить несколько важных практических аспектов эффективной оценки риска и предложить их работникам, работодателям, специалистам по гигиене рабочих мест, врачам и специалистам, принимающим решения.
MEASURING SURFACE GEOMETRY OF AIRPLANE WING BY MEANS OF TWO METHODS
Authors: Bručas Domantas , Sužiedelytė-Visockienė Jūratė
Published: June 2009

Determination of the geometry of aircraft surfaces has always been an extremely complicated task, though it is very important for the aerodynamic properties of the entire aircraft or its parts (like wings, body, rudders, etc.). Measurement of the geometrical properties of aircraft parts is especially difficult due to the smoothness of their surfaces. Here in this paper a short review of two methods of determining the shape of aircraft parts are given: one relies on determining point position by means of laser‐based scanning and another relies on photogrammetry. A comparison of the results of both methods applied to the same aircraft element is also presented. Santrauka Orlaivio paviršiaus geometrijos nustatymas visada buvo labai sudetinga užduotis, nors tai labai svarbu orlaivio daliu (sparnu, liemens, vairu ir kt.) ar viso orlaivio aerodinaminiu charakteristiku kontrolei. Nustatyti geometriniu orlaivio detaliu matmenis yra ypač sudetinga del jū lygaus paviršiaus. Šiame straipsnyje trumpai aprašyti du orlaivio daliu paviršiaus formos nustatymo metodai: vienas remiasi tašku koordinačiu nustatymu naudojant lazerinio skenavimo tipo matavimus, kitas ‐ fotogrametrinius matavimus. Taip pat pateiktas abiej u metodu palyginimas taikant juos to paties orlaivio elemento formos nustatymui.
AN OBSERVATIONAL WORKPLACE STUDY OF CARDIOVASCULAR VARIABLES IN AIR TRAFFIC CONTROLLERS
Authors: Ereminas Darius
Published: June 2009

The effects on health due to stress at work may be very different, depending on age, lifestyle, working experience, motivation, physical and mental health, and many other factors. The main objective of this study is to explore the performance of psycho‐physiological effects on the air traffic control staff employed at the state enterprise Oro Navigacija.

Santrauka

Profesinio streso sukelti efektai sveikatai gali būti labai skirtingi, priklausomai nuo amžiaus, gyvenimo būdo, darbines patirties, motyvacijos, fizineir psichines sveikatos bei daugelio kitu veiksniu. Šio darbo tikslas yra ištirti VI “Oro navigacija” dirbančiu skrydžiu vadovu darbo sukeliamus psichofiziologinius pokyčius.
WIND FARMS AND AVIATION
Authors: Novák Andrej
Published: June 2009

Wind is an increasingly important source of energy for the Slovak Republic. It is exploited by the use of turbines to generate electricity. Because of their physical size, in particular their height, wind farms can have an effect on aviation. Additionally, rotating wind turbine blades may have an impact on certain aviation operations, particularly those involving radar.

Santrauka

Vejas yra vis didejantis energijos šaltinis Slovakijos Respublikoje. Jis naudojamas generuoti elektra turbinomis. Vejo fermos pagal savo fizikini dydi ir ypač pagal aukšti gali tureti itakos aviacijai. Besisukančios vejo turbinu mentes gali tureti itakos tam tikroms aviacijos operacijoms, ypač susijusioms su radarais.
Absence ofMycobacterium tuberculosisin Arterial Lesions from Patients with Takayasu’s Arteritis
Authors: ARNAUD LAURENT , CAMBAU EMMANUELLE , BROCHERIOU ISABELLE , KOSKAS FABIEN , KIEFFER EDOUARD , PIETTE JEAN-CHARLES , AMOURA ZAHIR
Published: June 2009

Objective.

Previous studies have suggested thatMycobacterium tuberculosis(MT) could be involved in the pathogenesis of Takayasu’s arteritis (TA). The search for MT in arterial lesions of TA has never been assessed directly by sensitive methods. Our aim was to assess the presence of MT in arterial samples obtained in patients with TA.

Methods.

Fresh arterial samples were collected from 10 consecutive patients (9 women and 1 man, median age 42 yrs, range 19–67 yrs) with a diagnosis of TA according to the American College of Rheumatology criteria who underwent vascular surgical procedures for their disease. Three patients had recent onset of TA and 7 had longstanding disease. No patient had evidence of active tuberculosis. Arterial biopsies were collected during vascular surgical procedures, and were systematically studied by a pathologist specializing in vascular diseases. Presence of MT was assessed in the biopsies by acid-fast and auramine-fluorochrome stainings, mycobacterial cultures, and direct amplification test (DAT) for MT.

Results.

Histological examination showed active (n = 5) and inactive (n = 5) arterial lesions. MT was not detected in arterial lesions of either active or inactive TA, by acid-fast and auramine-fluorochrome staining, mycobacterial cultures, or DAT. No DAT inhibitors were found.

Conclusion.

Our study does not support a direct role of MT in the pathogenesis of arterial lesions in either recent or longstanding TA, but does not exclude the possibility of a cross-reaction between mycobacterial and arterial antigens.
Changes in Lipid Profile Between Flare and Remission of Patients with Systemic Lupus Erythematosus: A Prospective Study
Authors: URQUIZU-PADILLA MARIA , BALADA EVA , CHACON PILAR , PÉREZ EDUARDO HERMOSILLA , VILARDELL-TARRÉS MIQUEL , ORDI-ROS JOSEP
Published: June 2009

Objective.

To determine the lipid profile of patients with systemic lupus erythematosus (SLE) according to the disease activity, and to calculate the percentage of patients that diverged from optimal values.

Methods.

Serum was collected from 52 patients with SLE at flare and at remission. SLE disease activity was measured by using the SLE Disease Activity Index (SLEDAI). Clinical and biological measures were evaluated in both situations. Total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), and triglyceride (TG) levels were analyzed after overnight fasting. We also calculated the atherogenic ratios of TC/HDLC and LDLC/HDLC.

Results.

SLE patients had significantly higher median TC/HDLC and LDLC/HDLC ratios at flare than during remission: 4.5 ± 1.5 versus 3.9 ± 1.0 (p = 0.007) and 2.7 ± 1.1 versus 2.4 ± 0.8 (p = 0.015), respectively. The differences persisted after adjustments based on kidney disease and treatment but not after adjusting by creatinine clearance < 60 ml/min/1.73 m2in remission. The variation between flare and remission of the percentage of SLE patients with high-risk levels of lipid profile to desirable values, and vice versa, was statistically significant for the LDLC/HDLC ratio (9 vs 1; p = 0.021).

Conclusion.

Our results reflect a higher risk of atherosclerosis phenomena in SLE patients during flare than during clinical remission. This might explain the propensity to develop coronary heart disease in patients with SLE.
Serum Uric Acid Is Independently Associated with Metabolic Syndrome in Subjects with and without a Low Estimated Glomerular Filtration Rate
Authors: SEE LAI-CHU , KUO CHANG-FU , CHUANG FANG-HSIU , LI HONG-YI , CHEN YU-MING , CHEN HUNG-WEI , YU KUANG-HUI
Published: June 2009

Objective.

The relationship among serum uric acid (SUA), metabolic syndrome, and chronic kidney disease (CKD) is unclear. We examined whether SUA level is an independent risk factor for chronic kidney disease and whether the association between SUA and metabolic syndrome is affected by kidney function.

Methods.

We analyzed 28,745 subjects (17,478 men, 11,267 women, age 20–49 yrs) who underwent health examinations at this hospital between 2000 and 2007. Hyperuricemia was defined as SUA level > 7.7 mg/dl in men or > 6.6 mg/dl in women. Kidney function was assessed by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study equation modified for Chinese subjects. Impaired renal function with low GFR was defined as eGFR < 90 ml/min/1.73 m2. The UA-low GFR groups were defined according to the observed combination of hyperuricemia and low GFR: Group A (absence of both hyperuricemia and low GFR); Group B (presence of low GFR but no hyperuricemia); Group C (presence of hyperuricemia but not low GFR); and Group D (presence of both hyperuricemia and low GFR).

Results.

The prevalence of hyperuricemia, metabolic syndrome, and impaired kidney function with low GFR was 20.3% (27.6% in men, 8.9% in women), 7.6% (10.6% in men, 3.0% in women), and 9.9% (11.6% in men, 7.1% in women), respectively. The Pearson correlation between SUA and eGFR was only −0.26 (−0.21 in men, −0.22 in women; p < 0.001). In men, the age-adjusted odds ratio (OR) of metabolic syndrome was 1.41 (Group B), 2.45 (Group C), and 2.58 (Group D) in comparison with Group A. In women, the age-adjusted OR of metabolic syndrome was 0.83 (Group B), 5.47 (Group C), and 3.31 (Group D) in comparison with Group A.

Conclusion.

Hyperuricemia is prevalent in the Taiwan population. Hyperuricemia is only weakly associated with renal function, but is strongly associated with metabolic syndrome with or without a low eGFR.