bluuebunny/crossref_metadata_2025 huggingface dataset:
Stratigraphy of the White Limestone of Jamaica
Authors: Mitchell Simon F.
Published: March 2013

The lithostratigraphy of the White Limestone Group (Eocene-Miocene) of Jamaica is revised based on geological mapping across the northern part of the Clarendon block. Eight shallow-water formations are recognised which are from base to top: Healthy Hill Formation (new name): predominantly white grainstones; Troy Formation: recrystallized and dolomitized limestones; Swanswick Formation: white grainstones; Claremont Formation: pale micritic limestones (locally recrystallized and dolomitized); Somerset Formation: pink grainstones and packstones with large white globular foraminifers; Walderston Formation: pink grainstones; Browns Town Formation: white packstones and wackestones with abundant large lens shaped foraminifers and abundant corals; and Newport Formation: pale wakestones and carbonate mudstones. The facies and their foraminifer assemblages are interpreted in terms of sequence stratigraphy.
Occurrence of K-feldspar-bearing hydrothermal breccias in the Bouillante geothermal field (Basse Terre – Guadeloupe)
Authors: Patrier Patricia , Bruzac Sylvain , Pays Rebecca , Beaufort Daniel , Bouchot Vincent , Verati Chrystèle , Gadalia Alain
Published: March 2013

Surficial indicators of recent to present geothermal activity are present around Bouillante (Guadeloupe, French West Indies). Until lately, most mineralogical parageneses identified in this area were typical of low temperature alteration (< 100°C) with the occurrence of dioctahedral aluminous smectites accompanied by zeolites (heulandite-clinoptilolite) ± calcite ± silica ± kaolinite, as an evidence of the cap rock of the geothermal system. Recently, numerous boulders of highly silicified breccias containing high temperature minerals (> 200°C) have been identified in the Bouillante bay (Anse Marsolle). Their petrographic study revealed several hydrothermal parageneses typical of a multistage alteration process.

Stage 1) An early potassic alteration facies typical of a high-temperature geothermal system characterized by K-feldspar/adularia + quartz + pyrite. K-feldspars have been shown to be present both in the clasts (replacement) and cement of these breccias. They are associated with quartz whose textural properties have revealed fracturing associated with boiling.

Stage 2) An acid-sulphate advanced argillic alteration facies with the occurrence of jarosite, gypsum ± silica (≥ 150°C) as usually observed in the upper part of epithermal systems worldwide as marker of deeper boiling.

Stage 3) An argillic alteration facies (illite/smectite mixed layers ± smectite ± calcite). With temperatures typically ranging from 100 to 200°C, this alteration facies is associated with near neutral fluids of mainly meteoric origin as known in the present geothermal reservoir (pH = 5.4). This alteration is the later one as evidenced by petrographic observations.

These results highlight mineral assemblages and mineral textures characteristic of high temperature hydrothermal alteration in epithermal settings. The occurrence of these breccias involved the existence of eruptive events (magmatic/hydrothermal explosion) which ejected this material. Isotopic (oxygen, argon) and geochemical (trace elements) studies are now necessary to clarify the timing of these breccias and the nature and the connection of the original fluids with current geothermal fluids
Tuned in to the Earth … from the school EduSismo: the French educational seismological network
Authors: Berenguer Jean-Luc , Courboulex Françoise , Tocheport Audrey , Bouin Marie-Paule
Published: March 2013

Earthquakes are both troubling and fascinating because of their suddenness, the terrible destruction they can wreak and because they still remain unpredictable. This is why emphasis must be placed on preparation, especially in the school system where causes and effects of these hazards are studied. But trying to explain earthquakes, scrutinizing the earth’s depths, taking on the planet internal dynamics… entail moving into the inaccessible. In this respect seismology is a source of complexity and fascination.

Scientific culture is thus at the heart of seismic risk instruction. All of this is in what the “SISMOS à l’École” curriculum is involved, by implementing an educational program that allows a natural risk culture to be engaged through a scientific and technological approach.

The original and innovative aspect of this programme stems from giving students the opportunity to install a seismometer in their school. The recorded signals, reflecting regional or global seismic activity, feed into an on-line database, a genuine seismic resource centre and a springboard for educational and scientific activities.

The network ‘EduSismo’ (numbering some sixty stations installed in metropolitan France, the overseas departments and territories and a few French high schools abroad) is the outgrowth of an experiment conducted in the Alpes-Maritimes area some twelve years back. Since then, the programme implemented has gone beyond simply acquiring seismic signals, which has been procured by research and monitoring centres. By appropriating a scientific measurement, the student becomes personally involved and masters complex concepts about geophysics and geosciences. The development of simple devices and the design of concrete experiments associated with an investigative approach make it possible to instill the students, these future citizens, a high-quality scientific culture and an education about risks.

Today, this programme is expanding. New initiatives with Italian, British and Swiss partners are being put in place to share experiences and data in Europe.
Pre-Mesozoic origin and paleogeography of blocks in the Caribbean, South Appalachian and West African domains and their impact on the post “variscan” evolution
Authors: Villeneuve Michel , Marcaillou Boris
Published: March 2013

New geodynamical data from West Africa bring consistent informations on the pre-Mesozoic reconstruction within a large area running from the western Sahara to the Colombian cordillera. These new data support a Neoproterozoic Ocean (WANO) between the Amazonian (AMC) and West African (WAC) cratons previously to the Iapetus and Rheic oceans. We delineate 31 blocs detached from the surrounding three continents: NAC (North American Craton), AMC and WAC. 7 came from the WAC margin, 7 from the NAC, 6 from the AMC and 11 from an intermediate volcano sedimentary domain (COB) built on a 1200–1000 Ma oceanic crust. These imbricated blocks formed a tight mosaic by the Hercynian/Alleghanian tectonic event which gave way to the Pangea super-continent. But, during the Atlantic Ocean opening these blocks began to move. They were separated by new oceanic basins. However, previously to the Pangea, blocks from the COB domain formed two sets of garlands located on the northwestern Gondwana margin. The northern one moved to the North until the Silurian to collide the NAC (Taconic tectonic event) meanwhile the southern one remains on the Gondwana margin. All together were gathered by the Carboniferous/Permian time. Then, the framework for the opening of the Atlantic Ocean was not totally disconnected from the “Variscan” collage and many variscan weakness zones were re-used as initial breaking zones. Beyond this tectonic impact, the pre-mesozoic assemblage allows us to compare this “Caribbean” island arc with another one: the Indonesian “Banda” arc. Thus, West Africa is a geological key area for correlations between the Caribbean, the Appalachian, the Brazilian “Nordeste” and the West European domains and for the understanding of the Atlantic Ocean opening process.
Statistical models in seismology: Lesser Antilles arc case
Authors: Valmy Larissa A. , Vaillant Jean
Published: March 2013

Seismic risk calculation is based on stochastic models describing at best the seismic activity. The focus is on calculating earthquakes occurrences probability and analyzing spatiotemporal evolution of these probabilities. The point process theory is the main tool for modeling seismic data and taking into account past history prior to a given date. Thus, probability and statistical tools were developed by scientists from research teams located in regions with very high seismicity regions: California (Turcotte), Japan (Ogata) and New Zealand (Vere-Jones). Statistical inference is based on likelihood techniques in order to optimize information processing and projection strategy. We consider the ETAS model and analyze the epicenter and magnitude distribution of earthquakes occurred in the Lesser Antilles arc from 1999 to 2004. A comparison of different probability density functions for the triggered event times is performed.
Interactions of a Sandstone Acid System with Clays
Authors: Zhou Lijun , Nasr-El-Din H. A. , Al-Muntashri G. A.
Published: March 2013

Regular mud acid, which is composed of HCl and HF, has been extensively used to remove the formation damage in sandstone reservoirs; however, many problems may occur during stimulation treatments with this acid. To overcome many of these drawbacks, sandstone acid systems (HF and a phosphonic acid) have been used as an alternative to mud acid. However, very limited research has been performed to investigate the interactions of sandstone acid systems with clay minerals in sandstone reservoirs.

In this study, sandstone acid with different HF concentrations was used to evaluate the solubility of various clay minerals (kaolinite, bentonite, chlorite, and illite) as a function of time, and temperature. The Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) techniques were used to identify the reaction products. The concentrations of key cations in the supernatant were analyzed using ICP. 19F Nuclear Magnetic Resonance (NMR) spectroscopy was utilized for the first time to determine the reaction of sandstone acid with clay minerals.

Sandstone acid did not leach aluminum from chlorite. No AlF3 precipitate was identified by SEM analysis of the precipitates. The secondary reaction between clays and HF occurred at high temperatures and, as a result, the ratio of Si/Al decreased. 19F NMR results showed that all HF acid in the sandstone acid solution reacted with clays at a weight ratio of 10:1, while HF was detected in the sandstone acid solution after it reacted with sand particles for 24 hours at the same weight ratio. This work examined interactions occurring with the reaction of sandstone acid with clay minerals that have not been discussed before, and highlighted the effect of acid strength, reaction time, and temperature on the performance of sandstone acid.
Production Analysis in Multifrac Horizontal Wells Including the Effects of Adsorption, Mixed Wettability and Dual Porosity
Authors: Kalakkadu S. , Klinsky Alba A. D. , Callard J. G. , Devegowda D.
Published: March 2013

Production Analysis is critical for operators in field development to characterize the combination of the hydraulic fracture stimulation treatment and the reservoir in order to improve completion practices and increase profitability. Typical production analysis workflows endeavor to determine the permeability and extent of the reservoir as well as the length, conductivity, and stage completion efficiency of the stimulation treatment. The advent of multi-frac horizontal wells has motivated the characterization of this combined system through fracture-fracture interference production analysis by recognizing the geometry inherent in stimulation completions. Production analysis also provides an evaluation of in-situ system permeability which in turn provides an evaluation of fracture lengths and fracture conductivity. Fracture-fracture interference and subsequent production decline provides an evaluation of reserves and recovery.

However for shale gas and shale oil reservoirs, the kerogen in organic rich shales is generally considered to be hydrophobic leading to a dual porosity system of mixed wettability including hydrophilic inorganic pores. In addition to free gas production in the matrix, there is a significant contribution to reservoir performance due to the presence of adsorbed gas production. This work focuses on a comprehensive simulation-based study to quantify these effects in order to enhance our ability to characterize shale reservoirs from production trends. To account for multicomponent fluids in shale oil reservoirs, we also employ a compositional equation-of-state model to investigate the influence of natural fractures and adsorption on production performance.
Efficient and Accurate Monitoring of Rod Pump Well Performance Using Real Time Data Processing and Visualization.
Authors: McCoy J. N. , Capps Kay , Podio A. L. , Rowlan O. L.
Published: March 2013

Understanding the performance and behavior of a sucker rod pumping system can be a difficult and time consuming task but is a requirement to optimize the performance of a large number of wells by efficiently identifying and correcting production problems. Streamlined and optimized acquisition of dynamometer, fluid level and pressure data has been achieved using fourth generation wireless instrumentation that is quickly installed at the surface and is controlled by a user friendly graphical application that requires minimum user intervention.

During a well monitoring session the data records are acquired seamlessly without interruption of the operator's workflow. Results are displayed in real time including quantitative visualizations of the downhole rod pump operation, plunger motion, valve action and fluid flow. Pump intake and discharge pressures are computed and displayed in synchronization with plunger movement, pump liquid fillage, traveling valve operation and standing valve operation. The pump animation is computed by the solution of the wave equation using the polished rod load and acceleration data stream and presented simultaneously with the corresponding fluid distribution and pressures in the wellbore obtained from the acoustic fluid level survey. The user can see, at a glance, the total performance of the well and lift system without having to devote much time to interpret a conventional dynagraph or fluid level record. Evaluation of the performance of the well and artificial lift system is performed at the well so that reports and recommendations for optimization can be issued immediately.

This paper presents the physics and the practical aspects of the application of these advanced analysis and well monitoring tools. Case studies are presented showing analysis on a variety of wells.
Modeling and Analysis of Salt Cavern Natural Gas Storage
Authors: Barajas Pablo , Civan Faruk
Published: March 2013

Abstract

A rigorous modeling approach is developed for effective management and inventory analysis of natural gas storage in underground salt caverns by considering the interactions of storage gas with surface facilities through wells and surrounding salt formation. Computational fluid dynamics and heat transfer modeling approaches are implemented to simulate the strongly-coupled fluid mechanics and heat transfer problems involving the cavern gas storage. Effective numerical methods and algorithms implemented in this work successfully generate the wellbore temperature and pressure distributions, gas cavern temperature, pressure, and velocity distributions, and temperature and pressure distributions of the gas leaking into the surrounding naturally-fractured salt formation. Practical applications are performed concerning typical gas injection, storage, and production scenarios and inventory analyses for regular and irregular shaped caverns. Reversible and irreversible losses of natural gas into surrounding salt formation through natural defects such as natural fractures and defects resulting from deformation, ballooning, and aging effects are taken into account. Maximum amounts of gas that can be stored up to the pressure safety limit of caverns are shown to vary with the cavern shapes. Thus, the cavern gas inventory analysis is not only dependent on temperature, pressure, and total volume of the cavern but also the cavern shape. Accurate prediction of the natural gas storage performance and inventories based on the present comprehensive simulation approach can be instrumental in effective management and balancing of the natural gas supply and demand.
Single Trip Drilling System with an Integral Deflector Allows Reliable Curve Building in Challenging Formation
Authors: Hildebrand J. , Swadi S. , Desai P. , Ervin D. , Gregurek P.
Published: March 2013

The formation in Hemphill County, Texas and surrounding areas presents a number of challenges when drilling build section from a vertical pilot hole to form a horizontal lateral in the productive zone. The formation is hard and abrasive and it is difficult to anticipate rock properties downhole from one well to the next. The erratic nature of the formation results in unpredictable performance by the drill bit and steerable drilling assembly particularly in the build section of the curve. In many cases, the target build rates are not achieved forcing unnecessary multiple trips resulting in cost overruns.

To remedy the issue, a single trip drilling system was developed to provide a reliable kick-off setting leading to the designated landing point for the lateral. From the bottom up, the drilling system consists of a hydraulically set anchor, an integral deflector, a TCI rock bit mechanically attached to the top of the deflector, a positive displacement motor and measurement tools. The integral deflector provides a dependable kick-off point and a firm beginning in initiating the build section without having to rely on a cement plug or conventional tools requiring multiple trips. The procedure includes positioning the drilling system in the pilot hole at kick-off point, orienting the deflector face with MWD in a desired direction, installing the deflector by hydraulically setting the anchor, disengaging the BHA from the deflector and commencing drilling operations. All of these steps take place in a single downhole trip. Once the rock bit and the motor assembly pass the deflector, the sliding and rotating phase efficiently achieves the target build rate.

The authors will describe the system components and the running procedure. They will also discuss system performance in the Hemphill County application along with realized benefits to the operator, lessons learned and planned improvements.
Impacts of Reservoir Boundaries and Fractures Dimensions on Pressure Behaviors and Flow Regimes of Hydraulically Fractured Formations
Authors: Al Rbeawi Salam Jabbar Hussain , Tiab Djebbar
Published: March 2013

Abstract

Hydraulic fracturing process is an important stimulation technique that has been widely used in conventional and unconventional oil and gas reservoirs. The technique involves creation of fracture or fracture system in porous medium to overcome wellbore damage, to improve oil and gas productivity in low permeability reservoirs or to increase production in secondary recovery operations.

This paper introduces a new technique for interpreting pressures behavior of a horizontal well with multiple hydraulic fractures. The well extends in multi-boundary reservoirs having different configurations. The hydraulic fractures in this model can be longitudinal or transverse, vertical or inclined, symmetrical or asymmetrical. The fractures are propagated in isotropic or anisotropic formations and considered having different dimensions and different spacing. The study has shown that pressure responses and flow regimes are significantly influenced by both reservoir's boundaries and fractures' dimensions. Different flow regimes have been observed for different conditions.

New flow regimes have been introduced in this study. The first one is the early radial flow regime which represents the radial flow around each fracture in the vertical plane resulted due to the partial vertical penetration of hydraulic fractures. The second one is the second linear flow regime which represents the linear flow toward each fractures in the vertical plane normal to the wellbore resulted due to the long spacing between fractures. Third one is the third linear flow regime which represents the linear flow in the vertical plane parallel to the wellbore after the pressure pulse reaches the upper and lower impermeable boundaries.
Cement Evaluation Challenges in Horizontal Wells - Guidelines for Providing Meaningful Data
Authors: Batcheller Gary W.
Published: March 2013

In North America the primary drilling and completion activities are for horizontal wells. Inclined wellbores make it more difficult to get high quality cement log data and, hence, additional information is necessary for proper execution and evaluation. These guidelines intend to describe which information is required and other critical aspects that need to be considered for obtaining good quality data. Examples of both good and poor quality logs are shown.

The additional information that is needed for proper log execution and evaluation are drilling records such as a gamma ray log for depth control, casing/centralizer record, borehole size, deviation / dog leg severity data and geological data for formation tops and / or ground water identification. Cement slurry densities, maximum expected compressive strength plus pressure/rates used during cementing are also required. Log quality is reviewed with the following aspects in mind:

Common interpretation mistakes Tool selection Tool calibration Procedures during logging Log presentation formats Lightweight cement logging considerations

Using pertinent examples and evolving industry procedures, this paper provides necessary information for obtaining quality logs and performing a more effective cement evaluation for highly deviated or horizontal wells. Procedures and guidelines developed primarily for straight hole drilling have, unfortunately and too often, become the acceptable “norm”. Potential interpretation pitfalls have been included. These guidelines provided for will be useful for operators, service companies, and regulators alike to improve overall data and resulting interpretation quality.

Too many times relevant information is not provided and proper procedures are not followed resulting in a misleading or inaccurate interpretation of cement integrity. Therefore, incorrect decisions are being made. By adopting the guidelines presented in this paper better log quality data will result. This will then lead to better business decisions such as changing cementing/drilling procedures or determining if remedial repairs are needed. Better cement isolation could result in more effective stimulations and increased production or prevent fresh water contamination concerns or prevent some surface casing vent flow issues all of which could be very costly.
The Effect of Management Involvement on Vehicle Safety Improvement
Authors: Catten Corey , Johnson Casey
Published: March 2013

The importance of management involvement in any safety initiative is well understood in the industry. Through our work in vehicle monitors, we discovered three necessary factors for safe driving behavior: real-time audible feedback of unsafe behavior in the vehicle, 2) an environment where the driver can change small unsafe choices for the safer without penalty, and 3) involvement by management or another interested third party to review the driving history and take action if necessary. Over the past several years, we observed varying degrees of management involvement leading to varying degrees of success in the safety improvement in the fleets we monitor. This paper quantifies the effect of the management involvement in terms of measured unsafe driving events.

The paper applies to HSE professionals and management working on land transportation safety programs based on the industry best practice for land transportation safety.

The paper shows that management attitudes alone dramatically affect the outcome of vehicle safety programs. Since vehicle-related accidents are the highest category of fatalities in oilfield work, the significance of this fact is lives… saved or lost.
Physiological Responses of Linseed Seedlings to Iso Osmotic Polyethylene Glycol, Salt, and Alkali Stresses
Authors: Guo Rui , Zhou Ji , Ren GuangXu , Hao Weiping
Published: March 2013

The aim of this study was to evaluate the physiological responses of linseed (Linum usitatissimum L.) seedling growth after establishment to osmotic, salt, and alkali stresses and to elucidate the adaptive mechanisms involved. Stresses were generated by exposure for 10 d to different iso‐osmotic (–0.2, –0.5, –0.8 MPa) solutions of PEG 6000 (osmotic stress), 1:1, NaCl/Na2SO4 (salt stress), and 1:1, NaHCO3/Na2SO4 (alkali stress). The RGR decreased as osmotic potential decreased; decreases due to alkali stress were much greater than those due to osmotic stress or salt stress. This was demonstrated by greater reductions in water content and root system activity. Photosynthetic activity and pigment indices were nearly unchanged with increasing osmotic and salt stresses, but were severely inhibited under alkali stress. This implies that alkali stress may be mediated through Na+ uptake accumulation to toxic levels, leading to a decrease in photosynthetic pigments and damage to the photosynthetic apparatus. Massive Na+ influx may be the main cause of damage from alkali stress. The alkali stress causes precipitation of phosphate and metal ions, which causes a sharp decrease in ionic activity and in the free concentrations of various other ions. We found that proline synthesis decreased osmotic potential, remedied the shortage of inorganic anions, and maintained stability of the intracellular pH. Betaine contributions to osmotic adjustment were small because its ratio to total organic matter was very low. The accumulation of organic acids may be a central component of the adaptive mechanism by which ionic balance is maintained under alkali stress.
Marked Expansion of Exocrine and Endocrine Pancreas With Incretin Therapy in Humans With Increased Exocrine Pancreas Dysplasia and the Potential for Glucagon-Producing Neuroendocrine Tumors
Authors: Butler Alexandra E. , Campbell-Thompson Martha , Gurlo Tatyana , Dawson David W. , Atkinson Mark , Butler Peter C.
Published: March 2013

Controversy exists regarding the potential regenerative influences of incretin therapy on pancreatic β-cells versus possible adverse pancreatic proliferative effects. Examination of pancreata from age-matched organ donors with type 2 diabetes mellitus (DM) treated by incretin therapy (n = 8) or other therapy (n = 12) and nondiabetic control subjects (n = 14) reveals an ∼40% increased pancreatic mass in DM treated with incretin therapy, with both increased exocrine cell proliferation (P < 0.0001) and dysplasia (increased pancreatic intraepithelial neoplasia, P < 0.01). Pancreata in DM treated with incretin therapy were notable for α-cell hyperplasia and glucagon-expressing microadenomas (3 of 8) and a neuroendocrine tumor. β-Cell mass was reduced by ∼60% in those with DM, yet a sixfold increase was observed in incretin-treated subjects, although DM persisted. Endocrine cells costaining for insulin and glucagon were increased in DM compared with non-DM control subjects (P < 0.05) and markedly further increased by incretin therapy (P < 0.05). In conclusion, incretin therapy in humans resulted in a marked expansion of the exocrine and endocrine pancreatic compartments, the former being accompanied by increased proliferation and dysplasia and the latter by α-cell hyperplasia with the potential for evolution into neuroendocrine tumors.
Belief in a Day of Judgment and Death Anxiety: A Brief Note
Authors: Beshai James A. , Lester David
Published: March 2013

The reliability of a scale to measure belief in a day of judgment was assessed using a sample of 162 undergraduate students. The scale had good reliability, and 12 of the 20 items constituted a homogenous subset of items. Scores on the scale were moderately associated with scores on a traditional religiosity scale, but were not associated with fears of death and dying.
Validating the Functions of Identity Scale: Addressing Methodological and Conceptual Matters
Authors: Serafini Toni E. , Maitland Scott B.
Published: March 2013

Various studies have examined the validity of the Functions of Identity Scale; the current study addressed gaps in previous works. Its three main goals were to revise the Control subscale and establish its construct validity, to assess the structural validity of a five-factor model, and to establish the external validity of the subscales. Confirmatory factor analysis (CFA) was employed with a sample of 422 female and 107 male undergraduate students from two universities in Ontario, Canada. The analysis supported the construct validity of the revised five-factor measurement model and the new Personal Control factor. The external validity of each of the subscales was tested, and scale items were revised to increase clarity and readability (to a Grade 5.5 reading level). Rigorous validity testing, strong psychometric properties, low reading level, and a novel focus on the outer workings of identity formation make this scale an attractive addition to current identity measures.
Taking Purpose into Account in Experimental Psychology: Testing for Controlled Variables
Authors: Marken Richard S.
Published: March 2013

Experimental research in psychology is based on a causal model—the General Linear Model (GLM)—that assumes behavior has causes but not purposes. Powers (1978) used a control theory analysis to show that the results of psychological experiments based on such a model can be misleading if the organisms being studied are purposeful (control) systems. In the same paper, Powers presented evidence that organisms are such systems. Nevertheless, psychologists continue to use methods that ignore purpose because the behavior in most experiments appears to be non-purposeful (a caused result of variations in the independent variable). The experiments described in this paper show how purposeful behavior can appear to be caused by the independent variable when an organism's purposes are ignored. The results show how taking purpose into account using the control theory-based “Test for the Controlled Variable” can provide a productive new methodological direction for experimental research in psychology.
Testing Joiner's Theory of Suicide in Jail Inmates: An Exploratory Study
Authors: Simlot Rupendra , McFarland Kevin , Lester David
Published: March 2013

Thomas Joiner has proposed an interpersonal theory of suicide in which thwarted belongingness, perceived burdensomeness, and an acquired capability to commit self-harm predict suicidal behavior. In an exploratory study, a questionnaire was administered to 38 jail inmates to test the applicability of this theory to these inmates. Only thwarted belongingness was associated with past suicidal behavior and the inmates' own prediction of the likelihood of future suicidal behavior.
Emotional Dispositions and Substance Use: Mediating Effect of Alexithymia
Authors: Bonnet Agnès , Bréjard Vincent , Pedinielli Jean-Louis
Published: March 2013

Substance consumption behaviors can range from use to abuse, the latter including addictive behaviors. Relationships between emotionality, alexithymia and substance-consumption behaviors among young adults were investigated through an explanatory model wherein alexithymia fulfills a mediating function by acting as an emotion-adjustment process. 256 students (62.1% women) with a mean age of 20.7 yr. ( SD = 1.6), enrolled at two universities in southern France took part in the study. They filled out a substance-use questionnaire, the Émotionnalité positive et négative à 31 (EPN–31) emotionality scale, and the 20-item Toronto Alexithymia scale (TAS–20). Mediation analyses validated the hypothesis that emotional dimensions of alexithymia act as mediators between emotionality (negative emotionality and emotional arousal) and substance use. As a mediating factor, alexithymia may be regarded as a type of operational process that regulates emotions. These results could have important implications for clinical and therapeutic applications focusing on emotion-regulation strategies and substance use.
A Comparison Study of Depression and Quality of Life in Turkish Mothers of Children with down Syndrome, Cerebral Palsy, and Autism Spectrum Disorder
Authors: Tekinarslan Ilknur Cifci
Published: March 2013

This study aimed to compare the quality of life and depression levels in Turkish mothers of children with Down syndrome, cerebral palsy, and Autism Spectrum Disorder (ASD). An additional purpose is to identify whether the depression and quality of life levels of the mothers differ significantly based on demographic variables. Two hundred fifty-two mothers participated in the study. The World Health Organization's Quality of Life-BREF (WHOQOL-BREF–TR) assessment instrument was used to determine the mothers' quality of life and the Beck Depression Inventory (BDI) to characterize their depression. Mothers of children with cerebral palsy had significantly lower quality of life scores on the environment and national environment domains of the WHOQOL-BREF–TR than those of children with Down syndrome. No significant difference was observed in the depression of mothers. With increasing education and income, quality of life of the mothers increased whereas depression decreased. Moreover, depression increased and quality of life decreased in older mothers. Furthermore, the findings indicated significant negative correlations between mothers' depression and quality of life scores on all domains of the WHOQOL-BREF–TR.
Heavy-metal extraction capability of chalcogenoic aminophosphines derived from 1-amino-4-methylpiperazine
Authors: Sarıöz Özlem , Sürme Yavuz , Muradoğlu Vefa
Published: March 2013

Aminophosphine of the type (Ph2PNHR) derived from 1-amino-4-methylpiperazine and its chalcogen derivatives (Ph2P(X)NHR X = S, Se) were used as ligands in solvent extraction of metal picrates such as Cu2+, Ni2+, and Pb2+ from the aqueous to the organic phase. Influence of parameters such as pH of the aqueous phase, ligand concentration in the organic phase, and concentration of the extractant extracted from the aqueous to the organic phase was investigated to determine the ligands’ ability to extract metal ions. Metal picrate extraction was investigated at 25°C using UV-VIS spectrophotometry in dichloromethane in the absence and in the presence of Ph2PNHR and chalcogenides. The extraction results revealed that the extraction percentage of Cu2+, Ni2+, and Pb2+ metals was much higher at lower pH values, indicating an acidity dependent complexation equilibrium.
Influence of Corrosive Environment on Changes of the ZnAl40Cu3 Upper Alloy Layer
Authors: Michalik Rafał
Published: March 2013

Zn-Al alloys are used mainly because of their tribological properties as a material alternative to bronze, cast iron and aluminum alloys in bearings, and as a structural material. Improved properties of Zn-Al alloys can be obtained by the addition of copper , silicon and using of heat treatment. Tribological properties of alloys of the Zn-Al-Cu alloys, their structure has been well described in the literature. Far less are, however, studies on the effect of corrosive environments on the structure of the surface layer of the alloy. The purpose of this examination was to determine the effect of corrosive environment on the surface layer of the ZnAl22Cu3 alloy. Subject of examination was the unmodified alloy containing 40% Al mass. and 3%. Cu (Zn - remain). The tested alloy was subject of the following operations: soaking at the temperature of 185°C during 10 hours with cooling in water, soaking at the temperature of 380°C during 10 hours with cooling in water and soaking at the temperature of 380°C w during10 hours with subsequent soaking at the temperature of 170°C with cooling in water. Subject of tests structural examination were samples after potentiostatic tests carried out at potential E = 300 mV Ekor in 24 hours in an acid rain, pH = 3.5. In order to determine the microstructure of the examined coatings metallographic examinations were performed using optical and scanning microscope cooperating with EDS X-ray spectrometer. Quantitative analysis of the selected characteristic microareas determined from X-ray spectral analysis EDX.
Determination of Thermal Diffusivity and Influence of Defect Structure in Alloys Based on the Fe-Al System
Authors: Bernstock-Kopaczyńska E. , Jabłońska Magdalena
Published: March 2013

Alloys of the Fe-Al system are interesting due to occurrence of long-range order and many thermal vacancies at high temperature, which lead to not only significant hardening, but also cause changes of physical properties. High temperature diffusion is conditioned by structural defects in solids, such as vacancies, foreign atoms and dislocations influencing thermal characteristics of a solid solution, among others the thermal diffusivity coefficient. Measurement of thermal diffusivity was performed at room temperature using the laser flash method. For characterization of the defect structure, positron annihilation lifetime spectroscopy was used. The data were presented for alloys with 28 and 38 at.% aluminium without chromium and containing 5 at. % Cr addition. The results showed that thermal diffusivity decreased with aluminium content and deviation from stoichiometry. In the studies, different structural defects in the alloys were observed.
AC Magnetic Heating of Superparamagnetic Fe and Co Nanoparticles
Authors: Lukawska A. , Jagoo Z. , Kozlowski Gregory , Turgut Z. , Kosai H. , Sheets A. , Bixel T. , Wheatley A. , Abdulkin P. , Knappett B. , Houlding T. , Degirmenci V.
Published: March 2013

AC magnetic heating of superparamagnetic Co and Fe nanoparticles for application in hyperthermia was measured to find a size of nanoparticles that would result in an optimal heating for given amplitude and frequency of ac externally applied magnetic field. To measure it, a custom-made power supply connected to a 20-turn insulated copper coil in the shape of a spiral solenoid cooled with water was used. A fiber-optic temperature sensor has been used to measure the temperature with an accuracy of 0.0001 K. The magnetic field with magnitude of 20.6 μT and a frequency of oscillation equal to 348 kHz was generated inside the coil to heat magnetic nanoparticles. The maximum specific power loss or the highest heating rate for Co magnetic nanoparticles was achieved for nanoparticles of 8.2 nm in diameter. The maximum heating rate for coated Fe was found for nanoparticles with diameter of 18.61 nm.
Bounding of Effective Thermal Conductivity of Two-Phase Materials
Authors: Singh Ramvir , Kumar Sajjan , Beniwal Radhey Shyam
Published: March 2013

In this paper, we propose a new approach to obtain the upper and lower bounds for the effective thermal conductivity of real two-phase systems. The developed expressions are based upon the series and parallel combination of resistors. To incorporate the effect of random distribution of inclusions in the continuous matrix as well as the wide difference in the thermal conductivity of the constituents, a non-linear second-order correction term is introduced. This correction term is used to replace the volume fraction of inclusions in parallel and perpenducular thermal conductivity equations. The obtained upper and lower bounds are then compared with the Hashin and Shtrikman bounds [ and it is found that the modified bounds are narrower as compared to other previously developed bounds for effective thermal conductivity. The modified upper and lower bounds are then used in Chaudhary and Bhandaris model to predict the effective thermal conductivity of real two-phase materials. The predictions of the effective thermal conductivity using the modified relations match well with the experimental results.
Molecular Dynamics Simulation of Thermal Conductivity of Aluminum
Authors: Davoodi Jamal , Khoshkhatti Samaneh
Published: March 2013

In this research, the thermal conductivity of aluminum (Al) in macro scale was investigated by the molecular dynamics simulation technique. We used FORTRAN programming in the simulations and used a fixed number of atoms, N, confined to a fixed pressure, P, and maintained at a constant preset temperature, T, i.e. the NPT ensemble. The Sutton-Chen many-body potential was used to calculate energy and force. The temperature and pressure of the system were controlled by Nosé-Hoover thermostat and Berendsen barostat respectively. We could solve the equations of motion using the Velocity Verlet algorithm. We calculated the thermal conductivity of Al in the macro scale using the Green-Kubo method. Moreover, we have studied the effect of increasing temperature on the value of the thermal conductivity of Al. The obtained results showed that the computed thermal conductivities are in good agreement with experimental data.
Heat Transfer inside Elliptic Cylindrical Reactor: Effect of Bed Porosity
Authors: Silva Filho A.A. , Silva de Almeida J.P. , de Lima Antônio Gilson Barbosa
Published: March 2013

The study of heat transfer phenomenon in porous media by fluids percolated in the axial direction has been of interest to many researchers in various branches of science and technology. Applications are directed to different process such as filtration, distillation, absorption and adsorption in columns, drying and catalytic reactions in fixed beds. The literature has presented several solutions of the heat diffusion / convection equation in fixed bed reactors, but these studies are limited to a cylindrical geometry. In this sense, this work aim to present a pseudo-homogeneous three-dimensional model to describe the steady-state heat transfer within a fixed bed reactor with elliptic cylindrical geometry by considering variable porosity. The energy equation written in elliptical cylindrical coordinates and applied to the porous medium (particulate system) is discretized numerically using the finite volume method. Results of the temperature distribution within the bed are presented analyzed. It was verified that with increased porosity heat transfer inside the reactor tends to be more intense and thus, lower temperature gradients are found in all cross section of the reactor.
Statistical Diagnostic Thresholds of Rolling Bearings with Correlation of the Bearings Signal and its Environment Based on Cauchy Product
Authors: Lindstedt Paweł
Published: March 2013

During diagnostic thresholds research, sequence of numbers emerging from proper measurements, are analysed. These are sequences characterizing environment (e.g. amount of hours worked sequence x and sequence of numbers emerging from diagnostic signal measurement sequence y). Hence, two sequences exist: {x0, x1,, xm} and {y0, y1,, ym}. Relation between these sequences might be determined by Cauchy product. The Cauchy product can significantly expand opportunities of applications of signal processing and analysis. Auto and cross Cauchy products of signals as well as quotients and subtraction result of the diagnostic and environment signals, for the standard condition and the condition resulting from the current diagnosis can be determined. These allow to make diagnostics more precise, particularly in case of small number of measurements, and low accuracy of the diagnostics thresholds determined from them.
The Analysis of Finishing Tooling Influence on Contact Fatigue Researched by Profilometer
Authors: Labuda Wojciech , Charchalis Adam
Published: March 2013

The article presents the research results referring to the analysis of the influence of finish treatment ( lathing, grinding, burnishing) on the contact fatigue of steel applied to marine pump shafts. The research was performed on a roller 40 mm in diameter made of 304L stainless steel. Within the research, the optimalization of burnishing technological parameters was conducted on account of the minimalization of Ra surface roughness coefficient as well as the maximalization of SU degree of surface layer relative hardness [. The multi criteria optimalization conducted by min-max method [ with regard to minimum surface roughness as well as maximum degree of surface layer hardness demonstrated that burnishing process should be carried out at the following technological parameters: burnishing force 1.1 kN, burnishing speed 35 m/min, feed 0.13 mm/rev. In addition, the influence of the burnisher passes number on the surface layer quality was determined [.The paper will present the research results of contact fatigue examination of samples after finish machining.
Validity Check of the Assessment of a Jet Turbine Engine Regulation in Flight Using a Computer Simulation
Authors: Golak Karol
Published: March 2013

In this paper, a method of evaluation of the turbojet engine regulation condition in flight, based on information from its ground tests was presented. The tested engine was presented by the single comprehensive model which links input (in form of the modified signal mp4) and engine output (in form of the modified signal np2). Changes of the model parameters following during its operation can be defined using changes of the proposed simulation model parameters describing the engine operation both in flight and during ground tests.
Stochastic Model of Durability of Rolling Bearings Considering Assembly Innaccuracies
Authors: Tomaszewski Jerzy
Published: March 2013

This paper presents a method of determining the reliability function of rolling bearings operating under conditions of assembly error. Both the random nature of the assembly errors and the hour-by-hour durability of the bearing in question were considered. The perturbation method of second moments was used to solve the problem. This method allows for determining the moments of first and second order of the probability distribution of the safety coefficient, which is understood as the ratio of the actual durability in hours to the predetermined bearing durability in hours. As an example, the method of determining the distribution of the durability coefficient of a rolling bearing was presented for a situation of angular misalignment of coupled shafts.
Structure and Properties of Diamond-Like Carbon Coatings Deposited on Non-Ferrous Alloys Substrate
Authors: Tański Tomasz , Labisz Krzysztof , Lukaszkowicz Krzysztof
Published: March 2013

With the appliance of the development of modern technologies in the areas of surface engineering and related applications, the definition of the term hard coatings can be extended by the Plasma Assisted Chemical Vapor Deposition (PACVD) method. This is a cost-effective plasma deposition process, which can be used to improve surface layer properties, e.g. hardness and wear resistance of aluminium, but also magnesium alloy parts by creating a resistant thick coating on the component surface. In this paper there have been presented results of the structure and mechanical properties investigations of crystalline diamond-like carbon gradient/monolithic coatings (Ti/DLC/DLC) deposited onto magnesium alloy (Mg-Al) and aluminium alloy (Al-Si-Cu) substrate by Plasma Assisted Chemical Vapor Deposition (PACVD). A thin metallic layer (Ti) was deposited prior to deposition of gradient coatings to improve adhesion. Microstructure investigation was performed using scanning electron microscopy and transmission electron microscopy. Tests of the coatings adhesion to the substrate material were made using the scratch test. As an implication for the practice a new layer sequence can be possible to develop, based on PACVD technique. Wear test were performed using the ball-on-disk method.