bluuebunny/crossref_metadata_2025 huggingface dataset:
New Technology for Flow Assurance in an Extra Heavy Oil Field: Case Study in the Akacias Field
Authors: Ruiz Andres Javier , Plazas John Jairo , Ramirez Elkin Alberto
Published: September 2014

This paper has the objective of presenting new technology, ensuring flow in the extra heavy crude field. The idea of this paper is to outline a successful pilot study carried out in the Colombian Eastern Llanos region where the effect of chemical product (flow improver) is exposed during the production of fluids from the pilot study well and the reduction of naphtha injected into the wellhead (diluent used for the movement of the surface crude). As the main fundamental, the modification of the rheology properties of the crude through change in apparent viscosity due to the effect of loads and interfacial molecular tension within the fluid, enabling improved mobility of fluids from the reservoir to production facilities via surfactant resins that interact with the colloidal particles in the crude thus reducing its viscosity. The pilot is divided into two phases, the first phase consists of determining which of the two flow improvers produces the best performance, and the second phase consists of the application of the selected flow improver to reduce the dilution of naphtha, that is used during the processing of crude to reduce its viscosity.

Within the study, a financial evaluation is presented for each of the pilot phases, including a revision of the ESP pumps efficiency within different scenarios.

Finally one of the most telling conclusions is mentioned, as the flow improver enables the possible reduction of naphtha injection by dilution in values close to -30%, increasing well production to close to 40%.
CSS Performance in Sands of Samaria Tertiary Field, Mexico
Authors: Aguilar Maria G. , Robles Eliseo Mares , Cabra Garduza Carlos M. , Peralta Oscar Osorio
Published: September 2014

In this paper shown the results obtained in the Extra – Heavy Oil Samaria Tertary Field by Ciclic Steam Stimulation (CSS) along almost 6 years. We have identified the major variables affecting the process; the thickness of the sand has been identified as the principal parameter to affect the performance of CSS process. It has been found that the temperature decline in thermal production from 35 days to 200 days. For thin thickness loses energy about 40% and for net thickness upper 15 m loses energy about 10% from overburden and underburden formations.

Our primary interest was to optimize present operations and to find infill wells. Actually the recovery factor is 2.3; with the development plan has optimizate with the understanding of the CSS performance in the field, with recovery factor increment from 6.93 to 8.8 in the next three years.
Fluid Characterization and Flow Improvers Evaluation for Samaria Somero Field
Authors: Cruz-Andrade J. P. , Cabra C. G. , Mares E.. , Ramirez Jaramillo E. R. , Echavez-Ross G..
Published: September 2014

Samaria Somero field produces heavy and extra hevy oil. To mitigate the fluency problems present in this kind of fields is necessary to constantly evaluate chemical improvers such as Water-Base Flow Improvers (WbFI) and Oil base Flow Improvers (ObFI). The first type of improvers works by creating emulsions which generate partial solubility between the oil and water phases. The second ones focus on lowering the viscosity. The objective of both systems is to increase the fluency through the oil transportation process. These types of chemical systems are usually tested on the field, measuring its efficiency through the injection of different amounts of product to the wells, evaluating the oil production increments and wellhead pressure drops, during the injection of the enhancer. Because the parameters to evaluate the efficiency and compatibility can not be rigorously controlled on the field test, these assessments can be misleading, since the response of the well could be attributed to the chemical or how the well is operated. So it is not possible to evaluated and quantigy clearly the phenomenon that occurs when mixing a WbFI or ObFI with crude.

Given that field test have no strict control on the variables to assess the efficiency and compatibility of WbFI and ObFI, PEMEX in conjunction with the Mexican Petroleum Institute (IMP), developed an experimental methodology to evaluate these products with experimental tests.

The purpose of this paper is to show the results of laboratory analysis for the Samaria Somero fluid characterization process and present a new methodology to exam the Flow Improvers evaluation, which was used to evaluate 5 different companies' products in the market.
Charge Pump for Gassy Application Venezuela Faja Del Orinoco
Authors: Arredondo Manuel , Moreno Octavio , Delgado Javier , Soltys Tim , Svitich Jason , Dunn Lonnie , Bettenson John , Noble Evan , Gonzalez Juan Carlos
Published: September 2014

One of the major impacts on progressing cavity (PC) pumps is the amount of free gas that enters the pump intake. PC pumps can handle increased amounts of free gas but under certain conditions this can have detrimental consequences on pump life, decreasing pump performance and pump production capacity. The higher the gas rates through the pump the higher the internal temperature. This temperature increase accelerates elastomer degeneration and fluid penetration into the elastomer to the bonding agent. Having a high volume of gas entering the pump decreases the amount of fluid slippage which does not allow for an even pressure distribution throughout the entire length of the pump. This uneven pressure distribution increases the workload to the discharge of the pump causes a premature failure. In order to overcome these issues charge pumps technology was tested.

The study was completed in the Orinoco Belt, Petropiar field. This is an unconsolidated sandstone formation with high fluid flow rate wells, 430 bbls/d at an average of 11° API. Reservoirs change through their productive life varied the operational conditions in the Orinoco Faja wells. Historically intake pressures were higher than 500 psi, GORs average 25 scf/stb resulting in free gas levels lower than 50%. Recently, data shows intake pressure lower than 250 psi, GORS higher than 1000 scf/stb resulting on free gas levels over 90%.

This is the first charge pump installed in Petropiar field. The strategy for this project was to start identifying well candidates where charge pumps can improve the PC pumps performance through gas separation and reduction of gas volume fraction (GVF) at pump intake. It also considered a well facility's conditions in order to get more variables and the most accurate information for this trial evaluation. The overwhelming results after installing the charge pump allowed the expansion of this technology to different wells with similar conditions regardless of well fluid production rate, sand, or water cuts. This is all part of a combined effort for finding reliable and cost effective solutions for challenging applications.
Selection Criteria for Power Generation Systems to Minimise Environmental Impact
Authors: Welch Michael
Published: September 2014

In many countries, Heavy and Extra Heavy oil reserves are located in sensitive environments, remote from existing infrastructure. Heavy oil production is energy intensive, requiring the combustion of fossil fuels to produce the heat and power required. Burning fossil fuels creates a wide variety of emissions to atmosphere, such as the Carbon Dioxide (CO2) released by burning carboniferous fuels to combustion pollutants such as oxides of nitrogen (NOx). In addition, Heavy Oil reservoirs tend to be gas deficient, and often a low cost way of disposing of the small quantities of unwanted associated gas is to flare it, creating a new source of emissions.

The first part of this paper looks at how to minimise emissions from energy production by making best use of locally available fuels, such as associated gas, and employing energy efficient techniques such as Cogeneration. It then discusses how the three most common power generation technologies – gas turbines, reciprocating engines and steam turbines – can be applied to Heavy Oil operations to minimise the impact of fossil fuel combustion.

However, building and operating a power plant or energy facility of any kind, also has other impacts on the environment. There are transportation issues in getting the equipment to site in the first place, the human impact on the environment due to both construction and operation of facilities, the issue of disposal of produced wastes, and the need for continuous re-supply of the power plant with the consumable items and spare parts to keep it operational. This paper therefore also compares the consumable and maintenance needs of the three main power generation technologies to investigate the long term impact of operations on the environment.
Key Issues in Heavy Oil Waterflooding Projects
Authors: Vidal R.. , Alvarado R..
Published: September 2014

Waterflooding is an improved oil recovery (IOR) method commonly used worldwide. Some of the world's largest waterfloods are found on Lake Maracaibo, in western Venezuela. One such project is the Bachaquero-02 (Bach-02) which was initiated in 1967 as a peripheral water injection in an unconsolidated sandstone reservoir with average permeability of 350 mD and average oil gravity of 15° API. This waterflood project has been the subject of various studies that include conventional assessments, integrated full field and simulation studies. This paper presents a diagnosis of the impact that waterflooding has on Bach-02 heavy oil recovery, in view of a new approach that reveals mechanisms of heavy oil displacement by water. The findings of this field study are in accordance with empirical, experimental and simulation investigations recently reported in technical literature. Voidage Replacement Ratio (VRR) and Water Oil Ratio (WOR) analysis in this reservoir show particular behaviors associated with fluid flow characteristics in the reservoir; namely, periods of VRR less than 1.0 which activate mechanisms that stabilize WOR at values close to 1.0 and result in increased oil recovery. These mechanisms are explained by recent investigations as the flow of water-in-oil emulsions, and in situ formation of foams that benefit from chemical changes brought about by periods of underinjection.
Smart Water Injection for Heavy Oil Recovery from Naturally Fractured Reservoirs
Authors: Gachuz-Muro Heron , Sohrabi Mehran
Published: September 2014

Enhanced Oil Recovery (EOR) from carbonate reservoirs can be a great challenge. Carbonate reservoirs are mostly oil-wet and naturally fractured. For this type of reservoirs, primary production is derived mainly from the high permeability fracture system which means that most of the oil will remain unrecovered in the low permeability matrix blocks after depletion. Further difficulties arise under high pressure and high temperature conditions.

Oil recovery from carbonated rocks may be improved by designing the composition and salinity of flood water. The process is sometimes referred to as smart water injection. The improvement of oil recovery by smart water injection is mainly attributed to wettability modification in the presence of certain ions at high temperature. The resultant favourable wettability modification is especially important for naturally fractured reservoirs where the spontaneous imbibition mechanism plays a crucial role in oil recovery.

The objective of the work presented here was to experimentally investigate the performance of smart water injection for heavy oil recovery from carbonate rocks under high reservoir temperature. A series of coreflood experiments were performed using a group of carbonate cores in which smart water injection was tested under both secondary and tertiary injection conditions. The experiments were conducted at 92 °C using an extra-heavy oil. Seawater from Gulf of Mexico (GOM) was used in the seawater injection experiments and the smart water used in the tests was obtained by 10 times dilution of the seawater. Although concentration of SO42− is lower in the smart water, the occurrence of SO42− as anhydrite in carbonates may be sufficient to stimulate a similar reaction between the carbonated rock and the injected water with lower salinities at high temperatures. Seawater injection resulted in oil recovery ranging between 30% and 40% whereas smart water injection resulted in 60% oil recovery from the same system.

Additionally, analyses of brine composition before and after coreflood experiments confirmed that the effluent concentrations of SO42−, Mg2+ and Ca2+ changed compared to its original values in the injected water. The results indicated that, for some cases, the source of these ions was dissolution from the rock surface. The reactivity of the rock increased when lower salinity water was used.
Drilling of Shallow Horizontal Wells at Very Extended Stepouts in the Venezuelan Faja
Authors: Chamat Elias , Peñaranda Juan , Trejo Ely , Meneses Maria
Published: September 2014

The Orinoco Oil Belt or “La Faja”, located in Venezuela, is the biggest reservoir in the world holding heavy and extra-heavy oil stored in highly permeable non-consolidated sands. To maximize reservoir exposure to production from these low pressure reservoirs, long horizontal sections in the reservoir are needed. Because of this, longer horizontal sections are being drilled and will continue to be drilled in the Faja.

The Faja reservoirs dip towards the north where drilling of horizontal wells has been concentrated in the last three decades, in wells drilled to true-vertical-depths (TVD) from 2,500 ft to 4,000 ft. As drilling in the last five years in Faja has moved towards the south, wells have been completed at TVDs from 1,500 ft to 4,000 ft. The recent development of the Junin Division of Faja, in the last two years, has required placing the wells at southern reservoirs at TVDs from 1,200 ft to 1,500 ft. Drilling these shallow horizontal wells demands adequate planning and execution to manage risks coming from high dogleg severities drilled with downhole motors, such as cyclic stresses of bottom hole components, high torque and drag, poor hole cleaning, inadequate weight-on-bit transfer, pipe swaps and stuck pipe events. Despite of the operational limitations seen when drilling shallow ERD wells with motors, a good number of wells recently drilled in southern Faja have reached important regional records of horizontal footage drilled. The current shallow horizontal record was drilled at 1,231 ft TVD; this well also coincides to be a record for Venezuela in terms of horizontal section drilled. The TVD over horizontal step-out ratio, or Extended Reach Drilling ratio (ERD), for this well was 1 to 4.4, which also constitutes a regional record.

After different operators drilled in Junin 28 shallow ERD wells with downhole motors, PDVSA, PetroMiranda and the service company tried out a point-the-bit RSS in three new shallow ERD wells. This paper presents the optimization experience using RSS to drill for the first time shallow ERD wells in Junin Division. An operational and technical comparison of RSS versus motors in Junin operations, as well as progress in the learning curve is also presented.

The experienced gained drilling horizontal sections of 28 shallow ERD with motors and three more wells drilled in the 8½-in. horizontal drain with RSS has become in an important performance step change to start planning drilling new southern blocks of Junin Division, where reservoirs could be as shallow as 1,000 ft.
Geomechanics Coupled Fluid Flow in Heavy Oil Reservoirs Considering Cold Production
Authors: Alvarez L. L. , Alzate G. A. , Naranjo A..
Published: September 2014

Historically, the geomechanical behavior of a hydrocarbon reservoir has been modeled based on the classical theory of poro-elasticity, which considers absolute reversibility of deformation, which is liable to a porous medium when the mechanical state of the rock is altered. The sands associated with heavy oil formations are generally characterized by low levels of cohesion and density, which is viewed in an increased sensitivity of the rock to permanent deformation and hysteresis; hence it is not suitable to model these formations as if their rheological behavior is elastic. This set the need to construct a model, which describes the permanent plastic deformation that rocks from this kind of reservoir have.

The modeling of the stress-strain behavior of plastic porous media aims to evaluate the permanent deformation that the rock suffers and to study the impact of this phenomenon on the behavior of the reservoir permeability porosity and mechanical stability of the layers overlying (compaction, subsidence). Several theoretical research and experimental surveys have defined that most heavy oil reservoirs can be studied as elasto-plastic materials.

The purpose of this paper is to show the couple model of constitutive equations (stress-strain model) and fluid flow equations that describe the dynamic behavior of a heavy oil reservoir during an isothermal process, which deforms elasto-plastically, and thereby, to predict several geomechanical phenomena or consequence as productivity drop due to changes in the permeability, pore collapse, cap rock integrity, subsidence, among others, that allow an approach to the behavior of these kind of reservoirs in order to improve production processes and simulation.
Reservoir Characterization of Junín Area, Orinoco Oil Belt Region, Venezuela
Authors: Cocco Martín J. , Ernández Jesus E.
Published: September 2014

As conventional hydrocarbon supplies tighten, world energy consumption rises and new technology emerges, unconventional sources of hydrocarbons are increasingly contributing more to the world energy basket. As a consequence, the upstream petroleum industry has more sharply focused its efforts in studying unconventional reservoirs during the last decade, especially those with extra-heavy oil. Most of the reservoirs with extra-heavy oil accumulations are too geographically widespread to be commercially attractive. One exception is the Orinoco oil belt region, located in eastern Venezuela, which contains enormous deposits of extra-heavy oil.

Both international and national oil companies have formed Empresas Mixtas (joint ventures) with Petróleos de Venezuela (PDVSA) to explore and produce lease blocks in the Orinoco region during the last few years. The experience of these joint ventures shows that the extra-heavy oil can be economically extracted with cold production at higher production rates than those observed in other regions with hydrocarbons of similar characteristics (Dusseault, M. B.) The total developed acreage in production by JVs today represents only fraction of the potentially commercial area of the Orinoco Oil Belt, leaving a significant remaining undeveloped region.

The Orinoco oil belt is divided into four areas: Ayacucho, Boyacá, Carabobo and Junín. The authors conducted a detailed evaluation of PDVSA's Junín area reservoir data and revised technical interpretations and reached some key conclusions in the study. This paper summarizes reservoir characterization rationale and procedures and significant study findings, including those addressing assessed volumes of original oil in place and recovery factors.
Maximizing Asset Value by Waterflooding Based on a Hypothetico-Deductive Method for Formulation, Evaluation, and Selection of Exploitation Scenarios. Case Study Lower Lagunillas-03 Reservoir
Authors: Tillero Edwin , Mogollon Jose Luis , Gutierrez Isabel , Peretti Francis , Lujan Luis , Fernandez Enedis , Niño Pedro , Perdomo Carlos , Portillo Jackmary
Published: September 2014

The Lower Lagunillas-03 reservoir, in Maracaibo Lake, Venezuela, has been producing for more than 80 years from La Rosa (25 API gravity) and Lower Lagunillas (19 API gravity) formations. The average pressure is less than a 1/3 of its oil bubble point pressure; whereas more than 70% of the OOIP remains in place.

Several waterflooding projects (Modules) with different injection patterns have been implemented since last 40 years, which have shown different results in term of production behavior and oil recovery. Therefore, an optimal waterflooding scheme has not been identified yet for the fifth waterflooding module (Lower Lagunillas Formation) and also for future waterflooding modules to be implemented for revitalizing the potential of this mature reservoir.

It is essential in this case to ascertain the objective of an optimal waterflooding scheme in order to unlock the promissory oil recovery potential considering current reservoir conditions and financial resources. This was accomplished based on an innovative hypotetico-deductive method, which considers cycles of formulation-testing-analysis-emerging of hypotheses (scenarios), and starts with the formulation of a simple or relevant hypothesis (expectation) about a feasible exploitation plan. It is tested using a numerical or analytical model campaigned with economical optimization workflow and its results inquires to evaluate the hypothesis in the light of initial expectations as discarded or chosen, or whether some emerging hypotheses might be conducted and others might not. In turn, they are cycled until analysis of prediction determines probity of hypotheses or the refined research of hypotheses is stopped.

Contrary to initial expectations, many hypotheses about waterflooding patterns for the fifth module were tested, such as new horizontal injector-producer wells (direct line drive), inverted seven-spot, and inverted five-spot from existing wells. Nevertheless a substantially increased Net Present Value (2 times greater compared to Base Case) was reached by testing inverted five-spot patterns using infill drilling and extending the area to be flooded so that it emerges as a novel strategy for unlock the potential of this mature reservoir.
Mesophase Fluids Treatment: An Alternative to Clean up Heavy Crude Oil Wells in Mexico
Authors: Torres Jorge , Espinoza Juan Carlos , Pietrangeli Gianna , Morales Diana
Published: September 2014

Many different types of crude oils are extracted from Mexican reservoirs, and most of the crude oils from the northern region are heavy crude oil with API gravity between 15 and 20. Many fields in this area are mature and have been intervened as long as 50 years ago. As a consequence, the identification of the damage and selection of the right treatment is challenging for those wells. Furthermore, the type of completion used does not allow the use of production assemblies for intervention.

Traditional treatment techniques consist of reverse circulation using coiled tubing. In the first treatments, the majority used hot oil in cycles and BTEX solvents. Several of the interventions were not successful, and the logistics process was complicated. In some cases, the treatment led to asphaltenes deposition and emulsion blockages in the near-wellbore region.

Mesophase fluids based on microemulsion technology are a viable alternative remediation system for wellbore cleanup when low-producer wells experienced intervention. The fluids are carefully designed, have ultra-low interfacial tension, high oil solubilization, and good compatibility with formation fluids. They can be used to mobilize trapped fluids and solids in damaged wells, remove water blocks and in-situ emulsions, to name a few of their benefits. After many applications in Mexico and other countries, experience shows this fluids technology leads to more productive oil and gas wells because they can be remediated or protected from damage. Mesophase fluids are differentiated from conventional technologies by composition, their mechanism, and application. These novel fluids have low or no aromatics content or other solvents and easily diffuse through the formations. The application of the technology involves a carefully designed treatment train based on pills. The pills circulate from the annulus to the string assembly or reverse circulate to displace the fluids rapidly. The treatment is pumped close to the pay zone, with a radial fluid invasion of 1 to 2 feet into the formation, and then is allowed to soak overnight. More than 20 applications confirm the success of this technology in remediating heavy crude oil wells. In some cases the production increased by a 100%.
Understanding the Movable Oil and Free-Water Distribution in Heavy-Oil Sands, Llanos Basin, Colombia
Authors: Bustos Ulises , Salazar Giovanni , Aldana Ivan , Moreno Wilson , Zamora Henry
Published: September 2014

Colombia's Oil production is around 1.1 million barrels per day (bpd), where 57% is from Heavy Oil fields. Current oil recovery is in the 15% to 17% range; with targets to increase it up to 50% through different methods. A typical reservoir exhibits hydrocarbon viscosity variations in hundred of centipoises, with formation water salinity typically below 5000 ppm and heterogeneities driving a complex fluids distribution. Since the low amount of salt in these environments prevents low frequency conductive devices for contrasting water versus hydrocarbons, where additionally, resistivity profiles are ambiguous to assess fluids mobility in the reservoirs.

In this context, the incorporation of additional physics of measurements opens a new perspective in the reservoir evaluation in Llanos basin, by reducing uncertainties and helping in the initial reservoir characterization. The new generation of wireline measurements supporting the present job is represented by multifrequency dielectric propagation, radial magnetic resonance and dynamic testers, in addition to the conventional triple combo logs.

Since good-oil bearing rocks (high porosities and permeabilities, very clean sands, high oil saturations) do not guarantee oil production (very high water cut is likewise common), the identification of movable oil and free water volumes in low salinities is mandatory. Understanding its distribution across sands is also a critical factor in heavy oil environments.

As a resistivity and salinity-independent reservoir evaluation approach, the combination of dielectric dispersion and radial magnetic resonance, provides a valuable sensitivity for the evaluation of displaced oil, free and irreducible water, viscosity and rock quality variations. Dielectric Dispersion is the variation of relative permittivity and conductivity versus frequency, enabling pore fluids determination. With a dielectric analysis at two depths of investigation, integrated with NMR-based diffusion mesurements, a direct identification of movable oil under filtrate invasion conditions and free water presence is achieved.

The correlations encountered between the dielectric dispersion is encouraging; whereas a better understanding on the movable oil occurrence and estimation of the fluid to be moved during production is achieved. Discussions with case studies in Llanos Basin are presented in this paper.
An isoflavan and saponins from Astragalus depressus L.
Authors: Maamria Leyla , Haba Hamada , Lavaud Catherine , Harakat Dominique , Benkhaled Mohammed
Published: September 2014

In this study, nine known secondary metabolites were isolated from ethyl
acetate and n-butanol extracts of Astragalus depressus L. (Fabaceae family),
including one isoflavan, namely pendulone (1) and eight saponins, namely
cyclogaleginoside A (2), astrasieversianin II (3), astrasieversianin IV (4),
astrasieversianin VII (5), astrasieversianin VI (6), astrasieversianin XIV
(7), dehydrosoyasaponin I (8) and soyasaponin I (9). The structures of
compounds 1-9 were elucidated by using spectroscopic methods, including 1D
and 2D NMR, ESI mass spectrometry and comparison with literature data.
Correlates of Implicit Cognitive Line Length Representation in Two-Dimensional Space
Authors: Doty Richard L. , Koti Ajay , Landy Jeffrey , Shin Christina , O'Hara Thomas A. , Silas Jonathan
Published: September 2014

Twenty-eight sex- and age-matched participants, half dextrals and half sinstrals, were instructed to move a pen-sized planometer three inches (7.6 cm) while blindfolded. Under separate trials, movements were made at four angles, towards and away from the body, and at two distances from the body (30 cm, 53 cm). Half were made with the right hand and half with the left hand. Line estimates increased in length across blocks of trials in a linear fashion and progressively overestimated the three-inch imagined criterion. Lines made moving towards the body were longer than those made moving away from the body, implying an egocentric frame of reference in making the estimates. Line estimates made at an oblique angle differed significantly from estimates made at other angles. No influences of sex, handedness, or the hand used in making the estimates were observed. The findings suggest that motoric estimates of line lengths made without visual cues—a unique measure of an implicit cognitive concept—are significantly altered by temporal and spatial factors, but not by sex or hemispheric laterality.
Diversity oriented, efficient and sustainable synthetic protocol for the synthesis of structurally diverse drug-like complex heterocycles, incorporating privileged heterocyclic systems
Authors: Khandelwal Sarita , Rajawat Anshu , Tailor Yogesh Kumar , Jain Hemant Kumar , Kumar Mahendra
Published: September 2014

A diversity oriented, efficient and sustainable synthetic protocol has been presented for the synthesis of structurally diverse drug-like small heterocycles with structural complexity. The present synthetic strategy involves a three-component domino reaction of 2-aminobenzothiazoles, thiophene-2-carbaldehyde and carbonyl compounds in the presence of a catalytic amount of sulfamic acid as a recyclable ecofriendly acid catalyst.
Upgrading the Network of High Mountain Shelter as A Method of Restoring of Demographically Endangered Settlements in the Slovenian Alps
Authors: Čerpes Ilka , Pandol Nina , Fikfak Alenka
Published: September 2014

The paper focuses on the interdependence between the development of demographically endangered settlements and the frequency of mountain accidents in the Triglav National Park in the Slovenian Alps. Using statistical data analyses of the Mountain Rescue Association of Slovenia, field surveys and spatial information of the Surveying and Mapping Authority of the Republic of Slovenia, conclusions were reached, which redefined the existing settlement pattern of alpine shelters and mountain pastures, to encourage safe mountaineering and the development of tourism. The upgraded network of Alpine posts is designed as an upgrade of the existing system of providing safety for the visitors to the high mountain regions of the Triglav National Park. At the same time, it offers a new format of tourist services as an opportunity to develop local economies in demographically endangered environments. The dual function (rescue services and tourism) reduces investment and maintenance costs and increases the efficiency in the exploitation of the network of paths and Alpine posts, hence it is feasible also in demographically endangered areas. It is one of the operational tools for stopping further decline in population.
Sociological Research of Rural Areas in the Czech Republic and Cooperating Among Experts
Authors: Sálus Jiří , Maříková Pavlína , Kment Petr
Published: September 2014

This paper is aimed at relations among experts concerned with rural sociology in the Czech Republic. The research was focused on their troubles with cooperation and access to essential information for empirical and theoretical survey of the society in Czech rural space. The research is based on qualitative approach. Semistructured interviews with experts from scientific and academic sphere and documents study were used as the data collection. The goal of this research is to encourage the rural scientific community and to answer questions related to troubles in cooperation.
Should Renaturalised and Recultivated Landscapes Appear in Landscape Typology?
Authors: Luc Małgorzata , Szmańda Jacek
Published: September 2014

Landscapes constantly change under the influence of natural and anthropogenic factors. They can be destructive as well as leading to regeneration of landscapes which have been imbalanced. When this process occurs in a natural or human-controlled manner with the use of natural elements of the environment, it is called renaturalisation, and the resulting landscape - renaturalised landscape. Where landscape restitution occurs under the purposeful, sustainable and rational human influence, we talk of the recultivation process and the resulting landscape is termed recultivated. Examples of both of these terms added to landscape classification have been described based on several quarries existing within the City of Krakow.
The New Features of Landslide Relief Discovered Using Lidar – Case Study from Babia Góra Massif, Western Carpathian Mountains
Authors: Łajczak Adam , Czajka Barbara , Kaczka Ryszard J.
Published: September 2014

Basing on LiDAR data, the re-interpretation of the limit and distribution of the selected landslide forms in 9 test areas were carried out. The forms are located at the slopes of the monoclinal ridge of Babia Góra Mt. (1,725 m a.s.l.) in the flysch Western Carpathians. The earlier knowledge on these landforms is shown in the unpublished map at the scale of 1:5,000 which was prepared basing on geomorphological mapping. Basing on the newest information source, subtle geomorphic signatures of landslides were found, the dynamics of these forms and directions of their further development were determined. Local differentiation of deep-seated landslides was indicated according to the relation between the sandstone layer dip and slope inclination, slope length, and altitude of the location of headwaters. An attention was paid to polycyclic relief of the highest located landslide forms, which contain the elements of glacial and nival morphology, and some are modelled by debris flows.
Late Spring Freezes in Poland in Relation to Atmospheric Circulation
Authors: Ustrnul Zbigniew , Wypych Agnieszka , Winkler Julie A. , Czekierda Danuta
Published: September 2014

Late spring freeze events, a significant agroclimatic hazard, are investigated for Poland. Daily minimum air temperatures from 184 stations for the period 1951-2010 were used to analyze the frequency and conditional probability of late spring freezes. In addition, three classification schemes were employed to investigate the atmospheric circulation responsible for late spring freezes events. The findings suggest that knowledge of the airflow influencing late spring freezes can help to understand the complex historical trends and projected future changes in freeze risk for perennial crops
Long-Term, Seasonal and Short-Term Fluctuations in the Water Level of the Southern Baltic Sea
Authors: Wolski Tomasz , Wiśniewski Bernard
Published: September 2014

Aim of this work are analyses of oscillations sea levels in the Southern Baltic on a scale of short-term changes, seasonal and long-term (age). The study was based on observational data in different periods time for tide gauges station of the Polish coast. On the example of some storm situations presents the part of the baric wave and the wind in the formation of extreme sea levels. The primary cause of the annual variability of sea levels was the characteristics of the annual and semi-annual oscillations (the annual and semi-annual solar tide). In the work also determined the rate of long-term sea-level rise for the Polish coast.
Adaptive Leader-Following Consensus of Multi-Agent Systems with Unknown Nonlinear Dynamics
Authors: Wang Junwei , Chen Kairui , Ma Qinghua
Published: September 2014

This paper deals with the leader-following consensus of multi-agent systems with matched nonlinear dynamics. Compared with previous works, the major difficulty here is caused by the simultaneous existence of nonidentical agent dynamics and unknown system parameters, which are more practical in real-world applications. To tackle this difficulty, a distributed adaptive control law for each follower is proposed based on algebraic graph theory and algebraic Riccati equation. By a Lyapunov function method, we show that the designed control law guarantees that each follower asymptotically converges to the leader under connected communication graphs. A simulation example demonstrates the effectiveness of the proposed scheme.
Performance Characterization and Auto-Ignition Performance of a Rapid Compression Machine
Authors: Liu Hao , Zhang Hongguang , Shi Zhicheng , Lu Haitao , Zhao Guangyao , Yao Baofeng
Published: September 2014

A rapid compression machine (RCM) test bench is developed in this study. The performance characterization and auto-ignition performance tests are conducted at an initial temperature of 293 K, a compression ratio of 9.5 to 16.5, a compressed temperature of 650 K to 850 K, a driving gas pressure range of 0.25 MPa to 0.7 MPa, an initial pressure of 0.04 MPa to 0.09 MPa, and a nitrogen dilution ratio of 35% to 65%. A new type of hydraulic piston is used to address the problem in which the hydraulic buffer adversely affects the rapid compression process. Auto-ignition performance tests of the RCM are then performed using a DME–O2–N2 mixture. The two-stage ignition delay and negative temperature coefficient (NTC) behavior of the mixture are observed. The effects of driving gas pressure, compression ratio, initial pressure, and nitrogen dilution ratio on the two-stage ignition delay are investigated. Results show that both the first-stage and overall ignition delays tend to increase with increasing driving gas pressure. The driving gas pressure within a certain range does not significantly influence the compressed pressure. With increasing compression ratio, the first-stage ignition delay is shortened, whereas the second-stage ignition delay is extended. With increasing initial pressure, both the first-stage and second-stage ignition delays are shortened. The second-stage ignition delay is shortened to a greater extent than that of the first-stage. With increasing nitrogen dilution ratio, the first-stage ignition delay is shortened, whereas the second-stage is extended. Thus, overall ignition delay presents different trends under various compression ratios and compressed pressure conditions.
A Scenario-Based Method for Assessing the Impact of Suggested Woodland Key Habitats on Forest Harvesting Costs
Authors: Søvde Nils , Sætersdal Magne , Løkketangen Arne
Published: September 2014

Variable retention harvesting is acknowledged as a cost-effective conservation measure, but previous studies have focused on the environmental value and planning cost. In this study, a model is presented for optimizing harvesting cost using a high resolution map generated from airborne laser scanning data. The harvesting cost optimization model is used to calculate the objective value of different scenarios. By comparing the objective values, better estimates of the opportunity cost of woodland key habitats are found. The model can be used by a forest manager when evaluating what silvicultural treatments to implement or as an input for improving the nature reserve selection problem for woodland key habitats or retention patches. The model was tested on four real-world cases, and the results indicate that terrain transportation costs vary more than reported in the literature and that it may be worthwhile to divide the opportunity cost into its direct and indirect components.
Ending Open Defecation in Rural Tanzania: Which Factors Facilitate Latrine Adoption?
Authors: Sara Stephen , Graham Jay
Published: September 2014

Diarrheal diseases account for 7% of deaths in children under five years of age in Tanzania. Improving sanitation is an essential step towards reducing these deaths. This secondary analysis examined rural Tanzanian households’ sanitation behaviors and attitudes in order to identify barriers and drivers to latrine adoption. The analysis was conducted using results from a cross-sectional study of 1000 households in five rural districts of Tanzania. Motivating factors, perceptions, and constraints surrounding open defecation and latrine adoption were assessed using behavioral change theory. Results showed a significant association between use of improved sanitation and satisfaction with current sanitation facility (OR: 5.91; CI: 2.95–11.85; p = 0.008). Livestock-keeping was strongly associated with practicing open defecation (OR: 0.22; CI 0.063–0.75; p < 0.001). Of the 93 total households that practiced open defecation, 79 (85%) were dissatisfied with the practice, 62 (67%) had plans to build a latrine and 17 (18%) had started saving for a latrine. Among households that planned to build a latrine, health was the primary reason stated (60%). The inability to pay for upgrading sanitation infrastructure was commonly reported among the households. Future efforts should consider methods to reduce costs and ease payments for households to upgrade sanitation infrastructure. Messages to increase demand for latrine adoption in rural Tanzania should integrate themes of privacy, safety, prestige and health. Findings indicate a need for lower cost sanitation options and financing strategies to increase household ability to adopt sanitation facilities.
Mitochondrial Toxicity in Human Pregnancy: An Update on Clinical and Experimental Approaches in the Last 10 Years
Authors: Morén Constanza , Hernández Sandra , Guitart-Mampel Mariona , Garrabou Glòria
Published: September 2014

Mitochondrial toxicity can be one of the most dreadful consequences of exposure to a wide range of external agents including pathogens, therapeutic agents, abuse drugs, toxic gases and other harmful chemical substances. However, little is known about the effects of mitochondrial toxicity on pregnant women exposed to these agents that may exert transplacental activity and condition fetal remodeling. It has been hypothesized that mitochondrial toxicity may be involved in some adverse obstetric outcomes. In the present study, we investigated the association between exposure to mitochondrial toxic agents and pathologic conditions ranging from fertility defects, detrimental fetal development and impaired newborn health due to intra-uterine exposure. We have reviewed data from studies in human subjects to propose mechanisms of mitochondrial toxicity that could be associated with the symptoms present in both exposed pregnant and fetal patients. Since some therapeutic interventions or accidental exposure cannot be avoided, further research is needed to gain insight into the molecular pathways leading to mitochondrial toxicity during pregnancy. The ultimate objective of these studies should be to reduce the mitochondrial toxicity of these agents and establish biomarkers for gestational monitoring of harmful effects.
Electricity Generation and Wastewater Treatment of Oil Refinery in Microbial Fuel Cells Using Pseudomonas putida
Authors: Majumder Dip , Maity Jyoti , Tseng Min-Jen , Nimje Vanita , Chen Hau-Ren , Chen Chien-Cheng , Chang Young-Fo , Yang Tsui-Chu , Chen Chen-Yen
Published: September 2014

Microbial fuel cells (MFCs) represent a novel platform for treating wastewater and at the same time generating electricity. Using Pseudomonas putida (BCRC 1059), a wild-type bacterium, we demonstrated that the refinery wastewater could be treated and also generate electric current in an air-cathode chamber over four-batch cycles for 63 cumulative days. Our study indicated that the oil refinery wastewater containing 2213 mg/L (ppm) chemical oxygen demand (COD) could be used as a substrate for electricity generation in the reactor of the MFC. A maximum voltage of 355 mV was obtained with the highest power density of 0.005 mW/cm2 in the third cycle with a maximum current density of 0.015 mA/cm2 in regard to the external resistor of 1000 Ω. A maximum coulombic efficiency of 6 × 10−2% was obtained in the fourth cycle. The removal efficiency of the COD reached 30% as a function of time. Electron transfer mechanism was studied using cyclic voltammetry, which indicated the presence of a soluble electron shuttle in the reactor. Our study demonstrated that oil refinery wastewater could be used as a substrate for electricity generation.
Melatonin Regulates Aging and Neurodegeneration through Energy Metabolism, Epigenetics, Autophagy and Circadian Rhythm Pathways
Authors: Jenwitheesuk Anorut , Nopparat Chutikorn , Mukda Sujira , Wongchitrat Prapimpun , Govitrapong Piyarat
Published: September 2014

Brain aging is linked to certain types of neurodegenerative diseases and identifying new therapeutic targets has become critical. Melatonin, a pineal hormone, associates with molecules and signaling pathways that sense and influence energy metabolism, autophagy, and circadian rhythms, including insulin-like growth factor 1 (IGF-1), Forkhead box O (FoxOs), sirtuins and mammalian target of rapamycin (mTOR) signaling pathways. This review summarizes the current understanding of how melatonin, together with molecular, cellular and systemic energy metabolisms, regulates epigenetic processes in the neurons. This information will lead to a greater understanding of molecular epigenetic aging of the brain and anti-aging mechanisms to increase lifespan under healthy conditions.
Risk Measures and Portfolio Optimization
Authors: Gambrah Priscilla , Pirvu Traian
Published: September 2014

In this paper we investigate portfolio optimization under Value at Risk, Average Value at Risk and Limited Expected Loss constraints in a continuous time framework, where stocks follow a geometric Brownian motion. Analytic expressions for Value at Risk, Average Value at Risk and Limited Expected Loss are derived. We solve the problem of minimizing risk measures applied to portfolios. Moreover, the portfolio’s expected return is maximized subject to the aforementioned risk measures. We illustrate the effect of these risk measures on portfolio optimization by using numerical experiments.
Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness
Authors: Corcione Carola , Freuli Fabrizio , Frigione Mariaenrica
Published: September 2014

The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was also deeply investigated. A highly exothermal reaction, based on a self-activated frontal polymerization reaction, was supposed and verified trough a suitable temperature signal acquisition system, specifically realized for this measurement. This is one of the first studies carried out on the curing behavior of these peculiar cold-cured epoxy resins as a function of curing time and thickness.
Dynamics of a Parametrically Excited System with Two Forcing Terms
Authors: Sofroniou Anastasia , Bishop Steven
Published: September 2014

Motivated by the dynamics of a trimaran, an investigation of the dynamic behaviour of a double forcing parametrically excited system is carried out. Initially, we provide an outline of the stability regions, both numerically and analytically, for the undamped linear, extended version of the Mathieu equation. This paper then examines the anticipated form of response of our proposed nonlinear damped double forcing system, where periodic and quasiperiodic routes to chaos are graphically demonstrated and compared with the case of the single vertically-driven pendulum.