bluuebunny/crossref_metadata_2025 huggingface dataset:
Hierarchical Long-Term and Short-Term Production Optimization
Authors: van Essen G. M. , Van den Hof P. M. J. , Jansen J. D.
Published: December 2009

Model-based dynamic optimization of oil production has a significant potential to improve economic life-cycle performance, as has been shown in various studies. However, within these studies short-term operational objectives are generally neglected. As a result, the optimized injection and production rates often result in a considerable decrease in short-term production performance. In reality however, it is often these short-term objectives that dictate the course of the operational strategy. Incorporating short-term goals into the life-cycle optimization problem is therefore an essential step in model-based life-cycle optimization. We propose a hierarchical optimization structure with multiple objectives. Within this framework, the life-cycle performance in terms of net present value (NPV) serves as primary objective and short-term operational performance is the secondary objective. Within this structure, optimality of the primary objective constrains the secondary optimization problem. This requires that optimality of the primary objective does not fix all degrees of freedom (DOF) of the decision variable space. Fortunately, the life-cycle optimization problem is generally ill-posed and contains many more decision variables than necessary. We present a method that identifies the redundant DOF in the life-cycle optimization problem, which can subsequently be used in the secondary optimization problem. In our study we used a 3-dimensional reservoir in a fluvial depositional environment with a production life of 7 years. The primary objective is undiscounted NPV, while the secondary objective is aimed at maximizing short-term production. The optimal life-cycle waterflooding strategy that includes short-term performance is compared to the optimal strategy that disregards short-term performance. The experiment shows a very large increase in short-term production, boosting first year production by a factor 2, without significantly compromising optimality of the primary objective, showing a slight drop in NPV of only −0.3%.
Platform Life Extension
Authors: Hudson Brian G
Published: December 2009

This paper will detail a structured and holistic methodology to support the extension of the life of an offshore platform beyond that indicated by original design philosophy. The approach identifies the key asset reliability, integrity and process safety issues that need to be addressed in operating an asset beyond its design life. This methodology captures the key issues that arise in operating assets at or beyond design life, including; corrosion, obsolescence of equipment, change in design duties, change in oil or gas properties or production profiles, availability of historic information etc.

This methodology and has been applied to extending the life of the offshore oil and gas platforms in the UK, Danish and Norwegian shelf of the North Sea. In Norway it is a requirement to gain consent from the regulatory body prior to extending the life of a platform or field beyond original design. In the UK, the regulatory body sees such an extension in life as a significant and material change to the "Safety Case". In other parts of the world the shareholders, legislators and other stakeholders require assurance on the reliability and integrity of the asset.

The output from this type of study will identify the key Asset Integrity and Vulnerability risks for the platform or field and include a fully costed programme of activities that operators need to carry out to extend and continue to maintain the asset life.

With the volatile oil price and aging profile of existing offshore platforms, the ability for operators and prospective investors to run assets beyond the original design life, whether for the short, medium or long term and still maintaining high standards of HSE and Integrity Management, is of paramount importance and forms a key part of any strategy to manage current and future business risk.
Offshore Pipeline and Riser Integrity—The Big Issues
Authors: Marsh Jonathan , Duncan Phil
Published: December 2009

This publication examines the dominant corrosion and integrity issues affecting the offshore rigid and flexible pipelines and risers that exist in the North Sea, as identified from the experience of the authors and their companies. The aim is not to examine all possible integrity issues, but to identify those that appear to be causing the most problems. For many aging rigid pipelines extension of life to beyond the design criteria is becoming increasingly common, and the increasingly dominant integrity issues are associated with internal and external corrosion. With respect to external corrosion issues, anode depletion is an increasingly common phenomenon below the water line. At and above the water line, coatings often passed the end of their service life in the late 90s and were not renewed due to low oil prices and reduced fabric maintenance spending. For internal corrosion, different corrosion mechanisms dominate in gas, multiphase, oil and water pipelines. Dominant issues for gas and multiphase production are preferential weld corrosion and localized CO2 corrosion mechanisms occurring under scales, deposits or due to increasing H2S levels. In oil transport pipelines, as oil volumes reduce, water drop and MIC are increasingly problematic due to low flow, and pigging operations become vital. In water injection pipelines, aging infrastructure leads to both inefficient de-aeration and an increase in MIC due to contamination over many years. All these issues lead to a need for effective corrosion and integrity management.

The experience of use of flexible pipes is increasing exponentially and by definition it is ageing. Over the coming years an increasing number of flexible pipes will reach the end of their design life, therefore prudent operators should focus on understanding the integrity status of their flexible pipes. Understanding and effectively managing the integrity of flexible pipes is necessary to prevent, predict, and detect the presence of any loss of integrity. This publication presents an update on the guidelines (based on an ongoing Oil and Gas UK JIP) for developing and implementing an integrity management strategy. This approach utilizes the correct mix of inspection and assessment tools, and operating procedures that will allow the operator to assess the opportunity for life extension of flexible pipes. For specific issues, damage or rupture of the outer sheath and subsequent annulus flooding is also examined, as this is the commonest integrity problem that is encountered in practice.
Intelligent Top-Down Reservoir Modeling of New Albany Shale
Authors: Dahaghi Kalantari A. , Mohaghegh S. D.
Published: December 2009

Although the New Albany Shale of the Illinois Basin has been estimated to contain approximately 86 TCF of natural gas in place, the full development of this potentially large resource has not yet occurred. The intent of this study is to reassess the potential of New Albany shale using a novel integrated workflow, which incorporates field production data and well logs using a series of traditional reservoir engineering analyses with artificial intelligence & data mining techniques. The model developed using this technology is a full filed model and its objective is to predict future reservoir/well performance in order to recommend field development strategies.

In this integrated workflow unlike traditional reservoir simulation and modeling, we do not start from building a geo-cellular model. Top-Down intelligent reservoir modeling(TDIRM) starts by analyzing the production data using traditional reservoir engineering techniques such as Decline Curve Analysis, Type Curve Matching, Single-well History Matching, Volumetric Reserve Estimation and Recovery Factor. These analyses are performed on individual wells in a multi-well New Albany Shale gas reservoir in Western Kentucky that has a reasonable production history. Data driven techniques are used to develop single-well predictive models from the production history and the well logs (and any other available geologic and petrophysical data).

Upon completion of the abovementioned analyses a large database is generated. This database includes a large number of spatio-temporal snap shots of reservoir behavior. Artificial intelligence and data mining techniques are used to fuse all these information into a cohesive reservoir model. The reservoir model is calibrated (history matched) using the production history of the most recent set of wells that have been drilled in the field. The calibrated reservoir model is utilized for predictive purposes to identify the most effective field development strategies including locations of infill wells, remaining reserves, and under-performer wells. Capabilities of this new technique, ease of use and much shorter development and analysis time are demonstrated as compared to the traditional simulation and modeling.
Oilfield Emulsion Control: A Major Issue During Heavy Crude Oil Production
Authors: Opawale Adekunle
Published: December 2009

The dehydration of oil to meet pipeline water specifications usually involves the resolution of the intractable water in oil emulsions present in the crude oil, and the use of some separation equipments. However, emulsion resolution may be very problematic and challenging when highly stabilized heavy crude oil types are produced. They often require more chemical injection and time to be resolved. One such study was conducted to observe the effect of specific gravity and viscosity reduction on emulsion stability, which in turn is defined by no less than three parameters – Rate of water drop, Oil dryness and interface quality.

Several hours of demulsification bottle testing with a typical 20 0 API heavy crude oil, a light straight run Gasoline as a diluent to reduce the crude's viscosity, and a typical front-end demulsifier chemical for emulsion resolution were carried out. The crude oil was blended with Gasoline at different ratios in six 100ml test bottles. The emulsion blends at its wellhead temperature of 45 0 C were resolved with 2ppm of demulsifier chemical which is a reduced treatment rate from 5ppm. The experiment revealed a number of interesting trends.

Addition of about 5ml of Gasoline in one of the test bottles led to 63% reduction in the oil's absolute viscosity, without the use of any additional heat except that attained at the wellhead of the operator's oilfield. This sample dropped about 96% of its emulsified water after 5 minutes of chemical injection, with a very sharp oil/water interface. The top oil had trace Basic sediment and water BS&W, and the separated water, an improved Total Petroleum Hydrocarbon TPH of about 50ppm. These Data demonstrated a good quality and sellable dry oil, easy to handle and can be pumped with little cost since its viscosity is appreciably reduced. Besides the effluent water is safe for disposal at the operator's terminal. On the basis of this bottle test, this research could result into the following benefits to the Operator: A 60% reduction in chemical usage and logistics costs A 45% – 50% reduction in production chemical costs Reduction in the unavoidable use of heaters in oilfield for emulsion resolution Production of a high quality and sellable crude oil for export and improved oil in water content of the produced water discharge.

The case study discussed in this paper is that of a heavy crude oil emulsion collected from a major operator's flowstation in the eastern Niger delta area of Nigeria.
Petrophysical Evaluation and Sequence Stratigraphic Model of ‘Indigo Field’ in Greater Ughelli Depobelt, Niger Delta, Nigeria
Authors: Okeke Chinwendu O. , Mode Ayonma W. , Obi Ifeanyichukwu S. , Odokoh Anthony O.
Published: December 2009

Detailed Petrophysical studies and Sequence stratigraphic analyses of three wells in the ‘Indigo Field of Niger Delta was carried out using wireline logs and high resolution biostratigraphy. Three sequence boundaries (SB 27.3Ma, 29.3Ma and 32.4Ma) and maximum flooding surfaces (MFS 26.2Ma, 28.1Ma and 31.3Ma) were identified. Three systems tracts were delineated in wells A and B, while only two were delineated in well C. Nine reservoir units (A1-A9) analyzed in well A show porosity, permeability and Vshale of 13-18%, 89.35-2775.8md and 0.026-0.05v/v decimal, respectively. Reservoirs A1, A4, A7, A8, and A9 contain oil, A2 and A3 contain gas, and A5 and A6 contain water. Porosity and Vshale values for three reservoir units in well B (B1-B3) are 16-25% and 0.03-0.045v/v decimal, respectively. Reservoirs B1 and B2 contain water, and B3 contains gas. Six reservoir units (C1-C6) delineated in well C have average porosity, permeability and Vshale values of 19-24%, 1063.92-3674.4md and 0.05-0.1v/v decimal, respectively. Reservoir C1 contains oil and water; C2, C3 and C6 contain only water, and C4 and C5 contain oil only. Water saturation, moveable hydrocarbon index (MHI) and net sand count were 14-79%, 0.42-0.46, and 6-40m respectively, in well A; 24-65%, 0.55-0.56 and 7-26m in well B; and 21-67%, 0.44-0.54 and 11-22m in well C. Well A, being with thicker and more porous sands with lower Vshale is more productive than wells B and C.
Successful implementation of 9 5/8-in. casing drilling in Nigeria: Case history of AKAMBA-2
Authors: Kenga Yannick , Atebe Jude , Feasey Guy
Published: December 2009

Drilling-with-casing (DwC) is a field-proven technology that has seen its application showcased as an innovative solution to mitigate wellbore stability issues and reduce well-construction costs. This technology has been around for several years, but was first deployed by Total Exploration & Production Nigeria (TEPNG) in November, 2006 on the well AKAMBA-2.

AKAMBA-2 is a vertical exploration well drilled on the north-east sector of Total's Oil Mining Lease (OML) 102 offshore field (55 m water depth) in Nigeria. It was drilled as a stand-alone well using drilling-with-casing technology comprising 9 5/8-in.casing with PDC casing bit drilling shoe to drill the 12 1/4-in. section. By eliminating bit trips and other unplanned events related to conventional drillpipe drilling, this application resulted in significant time and cost saving and the attainment of a world record depth of 1,036 m for this size of casing drilling.

This paper will describe this first application of the drilling-with-casing technology in the Niger Delta, its challenges and the cost saving benefits achieved with its application.
Testing hourly reference evapotranspiration approaches using lysimeter measurements in a semiarid climate
Authors: Trajkovic Slavisa
Published: December 2009

Numerous approaches have been developed for estimating hourly reference evapotranspiration ET0, most of which require numerous meteorological data. In many areas, the necessary data are lacking and new techniques are required. The objectives of this study are: (1) to develop artificial neural networks for estimating hourly reference evapotranspiration from limited weather data; (2) to evaluate the reliability of obtained artificial neural networks (ANNs) and Food and Agricultural Organization—56 Penman Monteith (FAO-56 PM) equation compared to the lysimeter measurements; (3) to test the performance of the FAO-56 PM equation for hourly daytime periods using rc=70 s m−1 (PM70) and using a lower rc=50 s m−1 (PM50); and (4) to evaluate the reliability of obtained ANNs compared to the FAO-56 PM equation using an hourly dataset from a variety of locations. The accuracy of two reduced-set artificial neural networks (ANNTR and ANNTHR) and two FAO-56 Penman-Monteith equations with different canopy resistance values (PM50 and PM70) was assessed using hourly lysimeter data from Davis, California. The ANNTR required only two parameters (temperature and radiation) as inputs. Temperature, humidity and (Rn−G) term were used as inputs in the ANNTHR. The ANNTR and PM50 were best at estimating hourly grass ET0. The ANNTR approach was additionally tested using hourly FAO-56 PM ET0 data from California Irrigation Management Information System (CIMIS) dataset. The overall results recommended Radial Basis Function (RBF) network for estimating hourly ET0 from limited weather data. Also, the results support the introduction of new value for canopy resistance (rc=50 s m−1) in the hourly FAO-56 PM equation.
Solar radiation and ice melting in Lake Vendyurskoe, Russian Karelia
Authors: Leppäranta M. , Terzhevik A. , Shirasawa K.
Published: December 2009

Field experiments were conducted during two melting periods, April 2006 and April 2007, in Lake Vendyurskoe. The observation programme included weather, ice and snow thickness and structure, water temperature and solar radiation transfer through the ice. Albedo showed a systematic decrease from 0.5–0.8 for wintertime dry ice and snow to 0.1 for wet bare ice in spring, with spatial standard deviation of about 10%. The e-folding depth of light level was 60–80 cm for congelation ice and 15 cm for snow-ice. Light transmissivity of the ice cover increased from melting but decreased from ice deterioration; it varied between 0.25–0.35 in 2006, while in 2007 there was a systematic trend from 0.1 to 0.5 in six days. The heat budget was governed by net solar radiation with daily peaks up to 400–500 W m−2 on clear days. The average daily melt was 1.2 cm at the surface, 0.5 cm at the bottom and 1–2 cm (thickness equivalent) in the interior.
Comparative analysis of the composition of bacterial communities from two constructed wetlands for municipal and swine wastewater treatment
Authors: Arroyo Paula , Ansola Gemma , Blanco Ivan , Molleda Patricia , Calabuig Estanislao de Luis , Sáenz de Miera Luis E.
Published: December 2009

This work provides information about bacterial community structure in natural wastewater treatment systems treating different types of wastewater. The diversity and composition of bacterial communities associated with the rhizosphere of Typha latifolia and Salix atrocinerea were studied and compared among two different natural wastewater treatment systems, using the direct sequencing of the 16S ribosomal RNA codifying genes. Phylogenetic affiliations of the bacteria detected allowed us to define the main groups present in these particular ecosystems. Moreover, bacterial community structure was studied through two diversity indices. Ten identified and five non-identified phyla were found in the samples; the phylum Proteobacteria was the predominant group in the four ecosystems. The results showed a bacterial community dominated by beta-proteobacteria and a lower diversity value in the swine wastewater treatment system. The municipal wastewater treatment system presented a high diverse community in both macrophytes (Typha latifolia and Salix atrocinerea), with gamma-proteobacteria and alpha-proteobacteria, respectively, as the most abundant groups.
Estimation of Ascaris infection risks in children under 15 from the consumption of wastewater-irrigated carrots
Authors: Mara Duncan , Sleigh Andrew
Published: December 2009

Ascaris lumbricoides, the large human roundworm, infects ∼1,200 million people, with children under the age of 15 being particularly at risk. Monte Carlo quantitative microbial risk analyses were undertaken to estimate median Ascaris infection risks in children under 15 from eating raw carrots irrigated with wastewater. For a tolerable additional disease burden of 10−5 DALY (disability-adjusted life year) loss per person per year (pppy), the tolerable Ascaris infection risk is ∼10−3 pppy, which can be achieved in hyperendemic areas by a 4-log unit Ascaris reduction. This reduction can be easily achieved by wastewater treatment in a 1-day anaerobic pond and 5-day facultative pond (2 log units) and peeling prior to consumption (2 log units).
Estimation of norovirus infection risks to consumers of wastewater-irrigated food crops eaten raw
Authors: Mara Duncan , Sleigh Andrew
Published: December 2009

A quantitative microbial risk analysis—Monte Carlo method was used to estimate norovirus infection risks to consumers of wastewater-irrigated lettuce. Using the same assumptions as used in the 2006 WHO guidelines for the safe use of wastewater in agriculture, a norovirus reduction of 6 log units was required to achieve a norovirus infection risk of ∼10−3 per person per year (pppy), but for a lower consumption of lettuce (40–48 g per week vs. 350 g per week) the required reduction was 5 log units. If the tolerable additional disease burden is increased from a DALY (disability-adjusted life year) loss of 10−6 pppy (the value used in the WHO guidelines) to 10−5 pppy, the required pathogen reduction is one order of magnitude lower. Reductions of 4–6 log units can be achieved by very simple partial treatment (principally settling to achieve a 1-log unit reduction) supplemented by very reliable post-treatment health-protection control measures such as pathogen die-off (1−2 log units), produce washing in cold water (1 log unit) and produce disinfection (3 log units).
Social-epidemiological study for evaluation of water supply and sanitation systems of low-income urban community in Dhaka, Bangladesh
Authors: Mollah Kabirul A. , Aramaki Toshiya
Published: December 2009

This study aims at quantification of health losses, considering social and environmental factors. Morbidity and mortality cases of diarrhoea for children under five years old were used to estimate the disability adjusted life years (DALYs) lost for the target households in low-income communities in Dhaka, Bangladesh. Water supply facilities and sanitation systems, along with hygiene practices and their health outcomes, were studied at community level. Demographic, socio-economic and socio-cultural aspects were also studied to support the research findings and give a better understanding of the local conditions. The four selected communities, Ward 60 (W60), Ward 61 (W61), Ward 62 (W62) and Ward 65 (W65), all had different existing urban services such as water supply, sanitation, garbage management and drainage facilities. All of these services existed in W62, but W60 did not have any of the services; W61 had sanitation and drainage coverage, whereas W65 had only a water supply facility. The results conclusively showed that, compared with the null (absence of services) scenario (W60), the other three scenarios (W61, W62 and W65) showed a substantial decrease of diarrhoea (1.219, 1.284 and 2.052 DALYs/household/year, respectively) reported for children under five years old. Besides urban services, other socio-economic characteristics might also influence the prevalence of diseases.
Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries
Authors: Preston Kelsey , Lantagne Daniele , Kotlarz Nadine , Jellison Kristen
Published: December 2009

Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l−1 sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments—alum and Moringa oleifera flocculation—to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0–91.4%; moringa flocculation 14.2–96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01–0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters≥30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.
Microbial and metal water quality in rain catchments compared with traditional drinking water sources in the East Sepik Province, Papua New Guinea
Authors: Horak Helena M. , Chynoweth Joshua S. , Myers Ward P. , Davis Jennifer , Fendorf Scott , Boehm Alexandria B.
Published: December 2009

In Papua New Guinea, a significant portion of morbidity and mortality is attributed to water-borne diseases. To reduce incidence of disease, communities and non-governmental organizations have installed rain catchments to provide drinking water of improved quality. However, little work has been done to determine whether these rain catchments provide drinking water of better quality than traditional drinking water sources, and if morbidity is decreased in villages with rain catchments. The specific aim of this study was to evaluate the quality of water produced by rain catchments in comparison with traditional drinking water sources in rural villages in the East Sepik Province. Fifty-four water sources in 22 villages were evaluated for enterococci and Escherichia coli densities as well as 14 health-relevant metals. In addition, we examined how the prevalence of diarrhoeal illness in villages relates to the type of primary drinking water source. The majority of tested metals were below World Health Organization safety limits. Catchment water sources had lower enterococci and E. coli than other water sources. Individuals in villages using Sepik River water as their primary water source had significantly higher incidence of diarrhoea than those primarily using other water sources (streams, dug wells and catchments).
A new nozzle for dissolved air flotation
Authors: Zhang Y. , Leppinen D. M. , Dalziel S. B.
Published: December 2009

This paper examines an experimental study of optimal nozzle design for a dissolved air flotation system. The term optimal is in reference to field studies of bubble-floc agglomeration in an actual DAF tank. The primary mechanism of floc removal has been identified as bubble clustering. By understanding the significance of bubble clustering it was possible to design a nozzle that could be successfully operated at reduced saturation pressures while still achieving improved levels of turbidity in the post-DAF water.
Temperature dependence of chemical and microbiological chloramine decay in bulk waters of distribution system
Authors: Sathasivan Arumugam , Chiang Jacob , Nolan Paul
Published: December 2009

Chloramine decays in distribution system due to wall and bulk water reactions. In bulk water, the decay could either be due to chemical or microbiological reactions. Without such distinction it is not possible to model chloramine decay in an actual distribution system since microbiological decay depends on different factors compared with chemical decay. The dependence of chloramine decay on chemical reactions is mostly understood. Although it is widely accepted that microbiological reactions could accelerate chloramine decay, quantification had not been possible until the microbiological decay factor method was proposed. In this paper, the effect of temperature on microbial and chemical decay coefficients is presented. This was done by following the procedure of the microbiological decay factor method but by varying the temperature of incubation between 18 and 30°C. The procedure was repeated for several samples. The results indicated that it is possible to express temperature dependence of both microbiological and chemical coefficients using the Arrhenius equation within the tested temperature range. Estimated E/R values were found to be 3,551±705 K−1 and 6,924±1,700 K−1 for chemical and microbiological decay rates respectively. Traditionally, it is believed that every 10°C rise would double the decay rate coefficients. However, the E/R value estimated in this study shows that a 16–17°C temperature rise is needed to double the chemical chloramine decay rate. A possible application to predict residuals in summer using winter water quality results is demonstrated. Results indicated that microbial decay factor method could help pre-warning water utilities of possible residual loss in summer. Traditional indicators could not offer such distinction.
Photocatalytic removal of taste and odour compounds for drinking water treatment
Authors: Tran H. , Evans G. M. , Yan Y. , Nguyen A. V.
Published: December 2009

Photocatalytic degradation of geosmin and 2-methylisoborneol (MIB), which are two taste and odour compounds commonly found in drinking water supply sources, was investigated using an immobilised TiO2 photoreactor. It was found that the degradation of geosmin and MIB followed similar pseudo-first-order kinetics with reaction rate constants being approximately 0.025 min−1 for typical geosmin and MIB concentrations of 250 and 500 ng/L. The normalised formal quantum efficiency was calculated to be in the range of 162–182 L/mol. Influence of additives (i.e. sodium bicarbonate and alcohols) on the degradation process was also investigated. It was found that there was a small reduction in the degradation rate constants of geosmin and MIB with increasing sodium bicarbonate concentration. At 50 mg/L sodium bicarbonate the degradation rate constants decreased by approximately 5%. Similarly, for methanol and ethanol concentrations up to 35 and 50 mg/L, respectively, these constants were found to also decrease. While addition of sodium bicarbonate and alcohols was seen to have relatively small negative effects on the photocatalytic degradation performance, the magnitude of their influence was consistent with the hypothesis that the degradation mechanism of geosmin and MIB was predominately that of attack involving HO∙ radicals.
Survival of Clostridium spores in river water and in sand from a slow sand filter
Authors: Hijnen W. A. M. , Blokker-Koopmans C. H. W. , Heijnen L. , Medema G. J.
Published: December 2009

Spores of sulphite-reducing clostridia (SSRC; incl. C. perfringens) have been introduced in water quality monitoring for microbial safety of drinking water because of their higher resistance to water disinfection processes than E. coli. Interpretation of this parameter, however, is hampered by lack of quantitative data on the spore decay rates. We determined decay rates of environmental Clostridium spores in river water and in filter sand in a twelve year microcosm study at different temperatures. Decay was not significant at 3°C and limited at 15°C. First order decay rates in water and sand were in the same order of magnitude and ranged from of 0.001 up to 0.0023 d−1. Molecular typing of isolates of surviving SSRC showed diversity in the species at different temperatures. From the results in combination with literature data it was concluded that there is heterogeneity in the longevity of environmental SSRC. There is a need for more information on the survival of C. perfringens spores which is essential for interpretation of this parameter in water microbiological quality control.
First-Year College Students' Attitudes about End-of-Life Decision-Making
Authors: Weiss Gregory L. , Lupkin Lea N.
Published: December 2009

This study analyzes attitudes about treatment of the terminally ill among a group of first-year undergraduate students—a cohort that was in high school when intense publicity and extensive political and judicial involvement in the Terri Schiavo case occurred. Data for the study were collected by structured personal interviews with 201 randomly selected, first-year students in the first half of fall semester, 2005. Students clearly make distinctions in the propriety of active euthanasia, passive euthanasia, and physician-assisted death. Presented with a situation of a terminally ill patient in considerable pain, 65.1% of the students supported or strongly supported withdrawal of life-sustaining technology (passive euthanasia), 34.3% supported the physician providing the means of death to the patient (physician-assisted death), and 28.3% supported the physician actually administering a lethal injection (active euthanasia). A review of the literature of correlates of euthanasia attitudes in a variety of samples produced five potential types of influences: 1) general philosophical and religious beliefs; 2) fears about one's own death and dying process; 3) amount of information about and exposure to the issue of euthanasia; 4) characteristics of the community in which one lives; and 5) certain personal background characteristics. These categorical types produced 19 specific variables that were potentially related to euthanasia attitudes. The strongest predictor of attitudes varied among the three types of euthanasia, but political party affiliation had the most overall influence. Students self-identifying as Democrats were more likely than those self-identifying as Republicans to support euthanasia.
Conflicts of Interest in the Roles of the University Professor
Authors: Sugarman Stephen D.
Published: December 2009

American universities are increasingly proactive in dealing with conflict of interest problems of their faculty. Changing social norms, publicized scandals, and more have made both university administrators and faculty extra alert to the dangers of faculty infidelity to their roles as teachers and scholars. Personal interests — both financial and non-financial — appear increasingly to pressure faculty to behave inappropriately. Most faculty members resist those pressures. Yet, enough conduct that either is, or appears to be, improper has occurred to prompt the adoption by universities of an ever-more complex regulatory regime. This regime no longer relies primarily upon threats of after-the-fact punishment for gross deviations from professorial norms. Instead, universities have also enacted a wide array of in-advance restrictions. These include required disclosures by faculty members of certain private interests, prohibitions of specific faculty behavior, and specified instances in which faculty members must temporarily withdraw from their professorial roles in light of their private interests. This article draws especially upon the author’s experience at the University of California to illustrate the new system of regulation.
Motyw „Kuszenia na pustyni“ w SŁowianskiej literaturze Hagiograficznej
Authors: Dziadul Pawel
Published: December 2009

(poljski) Jednym z najistotniejszych, wykazujacych duza zywotnosc i sil? oddzialywania, motywow pismiennictwa hagiograficznego byl motyw 'kuszenia na pustyni', ktory bezposrednio nawiazywal do archetypowego, ewangelicznego obrazu kuszenia Chrystusa. Oryginalne obrazy walki duchowej pozostawili pierwsi Ojcowie Pustyni. Najbardziej rozbudowany schemat walki anachorety z szatanem i demonami nakreslil Atanazjusz Aleksandryjski w Zywocie Antoniego Wielkiego. Walka duchowa ascety stawala sie niezbednym elementem argumentacji hagiograficznej, ktorej glownym zadaniem bylo udowodnienie swietosci glownego bohatera zywota. Schemat duchowych zmagan ascetow poprzez hagiografie wczesnochrzescijanska i bizantynska trafil do slowianskich ?ywotow. Artykul prezentuje adaptacje motywu 'kuszenia' na wybranych przykladach: Zywota Petara z Koriszy, najstarszego Zywota Iwana Rylskiego Zywota Teodozjusza Pieczerskiego, opowiesci Pateryku Kijowsko-Pieczerskiego czy hagiograficznych fragmentow Powiesci minionych lat. Sama postac szatana w literaturze hagiograficznej pelnila istotna funkcje artystyczna i teologiczna, wystepujac jakoswoisty 'antybohater' kontrastujacy z postacia swietego. Asceta w drodze zmagan z wlasnym cia?em i z upersonifikowanymi myslami mial przede wszystkim stac sie idealem zycia monastycznego, miedzy innymi poprzez nasladowanie Chrystusa i wczesnochrze?cija?skich mistrzow zycia duchowego.
THz radiation sensors
Authors: Sizov F.
Published: December 2009

In the paper, issues associated with the development and exploitation of terahertz (THz) radiation detectors are discussed. The paper is written for those readers who desire an analysis of the latest developments in different type of THz radiation sensors (detectors), which play an increasing role in different areas of human activity (e.g., security, biological, drugs and explosions detection, imaging, astronomy applications, etc.). The basic physical phenomena and the recent progress in both direct and heterodyne detectors are discussed. More details concern Schottky barrier diodes, pair braking detectors, hot electron mixers, and field-effect transistor detectors. Also the operational conditions of THz detectors and their upper performance limits are discussed.
Can 1st-Year College Students Accurately Report Their Learning and Development?
Authors: Bowman Nicholas A.
Published: December 2009

Many higher education studies use self-reported gains as indicators of college student learning and development. However, the evidence regarding the validity of these indicators is quite mixed. It is proposed that the temporal nature of the assessment—whether students are asked to report their current attributes or how their attributes have changed over time—best accounts for students’ (in)ability to make accurate judgments. Using a longitudinal sample of over 3,000 first-year college students, this study compares self-reported gains and longitudinal gains that are measured either objectively or subjectively. Across several cognitive and noncognitive outcomes, the correlations between self-reported and longitudinal gains are small or virtually zero, and regression analyses using these two forms of assessment yield divergent results.
Stuttered and fluent speakers' heart rate and skin conductance in response to fluent and stuttered speech
Authors: Zhang Jianliang , Kalinowski Joseph , Saltuklaroglu Tim , Hudock Daniel
Published: December 2009

Background: Previous studies have found simultaneous increases in skin conductance response and decreases in heart rate when normally fluent speakers watched and listened to stuttered speech compared with fluent speech, suggesting that stuttering induces arousal and emotional unpleasantness in listeners. However, physiological responses of persons who stutter observing stuttering and fluent speech has not been measured. Research suggests that the mechanism responsible for listeners' reactions is the mirror neuron system. The mirror neuron system activates when perceiving and producing goal‐directed actions and forms the link between action perception and action production.

Aims: To compare physiological responses elicited via fluent and stuttered speech in fluent and persons who stutter groups.

Methods & Procedures: Participants included 15 adult persons who stutter (mean age = 29.7 years) and 21 normally fluent controls (mean age = 23.7 years). Participants watched and listened to six speech samples read by three persons who stutter speakers and three fluent speakers, while their skin conductance response and heart rate were recorded simultaneously. Participants' responses to each speech sample were defined as changes in mean heart rate and mean skin conductance response between 15 s before and 15 s during stimuli presentation.

Outcomes & Results: Both groups showed similar patterns of response: skin conductance response was significantly increased and heart rate was significantly decreased in response to stuttered versus fluent speech. Similar to previous findings, the highest skin conductance response measures were induced by the first presentation of stuttered speech, with the response attenuating on subsequent presentations, while the heart rate was stable over time.

Conclusions & Implications: Results confirmed past research that showed arousal and emotional unpleasantness when observing stuttering. Clinically, these results acknowledge the arousal and emotional discomfort in fluent speakers and persons who stutter. The physiological responses to stuttering and the underlying emotional aspects should be discussed in the therapeutic milieu with notions about coping strategies.
IDENTIFICATION OF ELASTIC PROPERTIES OF STIFFENED COMPOSITE SHELL
Authors: Kovalovs Andrejs , Ručevskis Sandris
Published: December 2009

In the present study a numerical-experimental method for the identification of the elastic properties of stiffened composite panel from experimental vibration analysis is carried out. The elastic properties of a panel are found by an identification procedure based on the method of experiment design, the response surface approach, and the finite element method. The results obtained were verified by comparing the experimentally measured eigenfrequencies with the numerical ones obtained by FEM at the point of optima. Santrauka Aprašomas skaitinis-eksperimentinis briaunotos kompozitines paneles tamprumo savybiu nustatymo metodas. Šioms savybems nustatyti taikytas identifikavimo metodas, kuriame sujungti skaitinio eksperimento planavimas, skaičiavimas baigtiniu elementu metodu bei gautu duomenu aproksimavimas. Identifikavimo rezultatus patvirtina pačios paneles dažniu eksperimentiniu duomenu palyginimas su skaitiniais baigtiniu elementu metodu aptiktu tamprumo savybiu rezultatais.
SECURITY ANALYSIS OF UAV RADIO COMMUNICATION SYSTEM
Authors: Rudinskas Darius , Goraj Zdobyslaw , Stankūnas Jonas
Published: December 2009

This paper presents analyzed questions of the safety of the information transferred by the radio connection link of the Polish UAV project “Aircraft for monitoring” SAMONIT. This safety is especially important for the design and use of unmanned aerial vehicles (UAV). This paper also presents the structure of the SAMONIT communication system, security threats to the radio connection system, and possible measures to ensure secure information.

Santrauka

Straipsnyje nagrinejami Lenkijos bepiločiu orlaiviu projekto SAMONIT (monitoringo lektuvas) radijo ryšiu perduodamos informacijos saugumo klausimai. Ypač svarbi yra radijo ryšiu perduodamos informacijos apsauga kuriant bepiločius orlaivius (BO) ir kitas nuotolinio valdymo transporto priemones. Straipsnyje pateikiama SAMONIT ryšiu sistemos struktūra, galimos gresmes informacijos perdavimui, saugumui bei integralumui; taip pat radijo ryšio sistemos apsaugos būdai bei priemones.
FLUTTER CALCULATION BASED ON GVT-RESULTS AND THEORETICAL MASS MODEL
Authors: Chajec Wojciech
Published: December 2009

Ground vibration tests (GVT) are a typical source of data for flutter prediction. In this paper, a simple, lowcost method to calculate flutter is presented. In this method, measured frequencies, mode shapes of an airplane are used and, additionally, the theoretical mass model of it. If the theoretical mass model is used, it is possible to calculate generalized masses of modes and cross mass couplings between them. The mass couplings of normal modes should be zero. Orthogonalization is correction of the mode shapes to lead the couplings to zero. The possible orthogonalization methods are presented in chapter 2. Based on eigenmodes of airplane configuration during GVT, it is possible to determine the eigenmodes of the same free airplane after a relatively small mass change, i.e. for another mass distribution that was not investigated by GVT. In the procedure presented in chapter 3, it is assumed that geometric and stiffness properties do not change. The methodology was used in the own flutter calculation software that is useful for flutter prediction of light airplanes and sailplanes.

Santrauka

Dažnuminiai bandymai žemėje yra tipinis informacijos šaltinis flaterio skaičiavimui. Šiame straipsnyje pateikiamas paprastas ir pigus flaterio skaičiavimo metodas. Šiame metode naudojamos lėktuvo išmatuotų dažnuminių modų formos ir teorinis lėktuvo masių modelis. Naudojant teorinį masių modelį galima apskaičiuoti apibendrintas modų mases ir masių ryšius tarp jų. Normalinių modų masių ryšys turi būti lygus nuliui. Ortogonalizavimu koreguojamos modų formos, siekiant ryšius sumažinti iki nulio. Galimi ortogonalizavimo metodai pateikti antrame skyriuje. Remiantis lėktuvo laisvųjų svyravimo modomis, gautomis dažnuminių bandymų žemėje metu, galima nustatyti kitokio masių pasiskirstymo įtaką laisvųjų svyravimų modoms. Procedūroje, pateiktoje trečiame skyriuje, manoma, kad geometrinės ir standumo savybės nesikeičia. Ši metodologija buvo panaudota savoje programinėje įrangoje flateriui skaičiuoti, kurią galima naudoti lengvų lėktuvų ir sklandytuvų flaterio skaičiavimui.
Pentacam Scheimpflug Quantitative Imaging of the Crystalline Lens and Intraocular Lens
Authors: Rosales Patricia , Marcos Susana
Published: December 2009

Purpose:

To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH).

Methods:

Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland).

Results:

Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness.

Conclusions:

The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index. [
J Refract Surg.
2009;25:421–428.]