Crude Oil Resources Research Articles

Theoretical Study of CO Adsorption and Activation on Orthorhombic Fe7C3(001) Surfaces for Fischer–Tropsch Synthesis Using Density Functional Theory Calculations

Fischer–Tropsch synthesis (FTS), which converts CO and H2 into useful hydrocarbon products, has attracted considerable attention as an efficient method to replace crude oil resources. Fe-based catalysts are mainly used in industrial FTS, and Fe7C3 is a common carbide phase in the FTS reaction. However, the intrinsic catalytic properties of Fe7C3 are theoretically unknown. Therefore, as a first attempt to understand the FTS reaction on Fe7C3, direct CO* dissociation on orthorhombic Fe7C3(001) (o-Fe7C3(001)) surfaces was studied using density functional theory (DFT) calculations. The surface energies of 14 terminations of o-Fe7C3(001) were first compared, and the results showed that (001)0.20 was the most thermodynamically stable termination. Furthermore, to understand the effect of the surface C atom coverage on CO* activation, C–O bond dissociation was performed on the o-Fe7C3(001)0.85, (001)0.13, (001)0.20, (001)0.09, and (001)0.99 surfaces, where the surface C atom coverages were 0.00, 0.17, 0.33, 0.33, and 0.60, respectively. The results showed that the CO* activation linearly decreased as the surface C atom coverage increased. Therefore, it can be concluded that the thermodynamic and kinetic selectivity toward direct CO* dissociation increased when the o-Fe7C3(001) surface had more C* vacancies.

Long-term aging performance study of asphalt with different composition

Thin film oven tests (TFOT), pressure aging tests (PAV) for 5 h, 10 h, 15 h, 20 h were carried out on asphalts from 6 crude oil resources. Conventional and dynamic shear rheological tests (DSR) were carried out on samples at different aging degrees, respectively to evaluate the aging performance of asphalt with different composition. The main conclusions are as follows: asphalt composition had obvious influence on the long-term aging performance, in which the asphaltene content of asphalt is negatively correlated with the long-term aging performance of asphalt. According to experimental results of aging process influence on storage modulus G', A3, A5 and A6 asphalts had worse anti-aging performance than A1, A2 and A4. Meanwhile based on test results of aging process influence on loss modulus G", A1, A2 and A4 asphalts had worse anti-aging performance than A3, A5 and A6 asphalt.

OWNERSHIP AND CONTROL OF NATURAL RESOURCES IN NIGERIA: RUMOR VS. REALITY

The paper examined and interrogated the concept of ownership and control as it affects crude oil and solid minerals right vis-à-vis its impact on the current intergovernmental relations between the federal government and the natural resources bearing states in Nigeria. The paper adopted doctrinal research method. The paper examined two extant legislations namely; the Petroleum Act and the Minerals and Mining Act and found that both Acts have extensive provisions that have adequately provided for and vest ownership and control over crude oil and solid mineral resources in the federal government of Nigeria. The work found that institutional agencies such as the Nigerian Security and Civil Defense Corps and other related bodies actually carry out enforcement of the provisions of the Act against crude oil theft and establishment of illegal refineries in the Niger Delta Region. However, the paper also found that the enforcement mechanism of the Minerals and Mining Act by its institutional framework is rather weak. The work, therefore, recommends, among other things, that the federal government of Nigeria should reduce dependent on crude oil exploration and its attendant proceeds to solid minerals exploration because the country does not only have abundant solid minerals, but it is also because solid minerals have a great and wider international patronage than crude oil.

Performance and emissions evaluation of diesel engine fueled with exhaust gas energy preheated CAOME biodiesel

Abstract We are running out of crude oil resources, biodiesel is a promising alternative. However, the usage of biodiesel and its blends are associated with problems in atomization of fuel. The main reason is the high viscosity of oils extracted from green matter. The viscosity of oils is inversely proportional to temperature i.e. as temperature increases the viscosity decreases. Present study discusses the effects of preheated biodiesel and its blends on the performance and emissions of diesel engines. The supply of preheated biodiesel increases thermal efficiency (7.3%) and decreases CO, HC emissions but result in increase in NOx emissions.

Preliminary Analysis of the Use of Solid Biofuels in a Ship’s Power System

Abstract This paper presents the results of applying ennobled solid biomass via mechanical compaction or torrefaction as fuel for ships, in terms of fire safety, environmental protection, the increase in liquid fuel prices and the dwindling resources of crude oil. The object of investigation is a ship of the ro-pax ferry type, with low cruising range, which is intended for service on the Baltic Sea. The ship’s power system is discussed and the results of calculations of the thermal cycle for a steam turbine power plant are presented. We present a simplified comparative analysis of a fuel bunker for a ship with a power plant including biomass fired boilers, and for a ship with a conventional solution of a motor power plant supplied by ultra-low sulphur fuel originating from crude oil. The advantages of applying a fluidised bed biomass fired boiler are highlighted, and selected results from tests of this boiler are presented. In addition, we assess potential fire hazards on the ship resulting from the storage and transport of pellets, and from pellets after torrefaction.

Experimental Investigation and Modelling of Asphaltene Precipitation during Gas Injection

Due to the limited crude oil resources, the role of enhanced oil recovery (EOR) techniques in the production of the oil that has not been extracted during the primary and secondary oil production techniques is crucial. Gas injection is known as an important EOR technology, but one of the main concerns during gas injection is asphaltene precipitation and deposition within reservoir formation. In this study, the effect of temperature (ranges 376-416 K) and concentration of injected gas (N2 (10, 20 and 40, mole percent) and first separator gas (20, 40 and 60, mole percent)) on the onset pressures and amount of asphaltene precipitation in one of the Iranian oil reservoirs were investigated. Two series of experiments were accomplished on live oil by gravimetric method; first: injection of different concentrationsof nitrogen and first separator gas at reservoir temperature and under different pressures (3000-8000 psia) and second: natural depletion at different temperatures. Besides, the experimental data of asphaltene precipitation due to N2, first separator gas, and also CO2 injection were compared together. Finally, the experimental data were modeled with a solid model. The results indicate that the amount of asphaltene precipitation due to N2 injection (0.1-0.2 wt %) is lower than the first separator gas and CO2 injection at the same concentration. Experiments show that in the range of experimental temperatures the asphaltene precipitation changes up to 0.06 wt %. For pressures below the bubble pressure (~ 4700 psi), precipitation changes directly with temperature, and indirect relation is observed for pressures above the bubble point pressure.

Oil Production by Polish Companies in Poland and Abroad

The article discusses a very important problem of oil production. Oil, recognized as a major source of economic development, is themain energy source of the modern world. Unfortunately, Poland has limited oil reserves. However, the production, which meets onlyabout 4% of the demand, is carried out. Oil deposits in Poland are found in the Carpathians, in the Carpathian Foredeep, in the Polish Lowlands, and in the Polish Exclusive Economic Zone of the Baltic Sea. Initially, deposits in the Carpathians were of the greatesteconomic importance, but these are already depleted to a great extent. Currently, oil deposits in the Polish Lowlands are of the greatesteconomic importance. The largest deposit is BMB (Barnówko-Mostno-Buszewo) near Gorzów Wielkopolski. In total, in Poland oilresources amount to 23 598.46 thousand tons, of which 61.37% accounts for industrial resources (14 482.15 thousand tons). The article presents crude oil resources in Poland by regions, i.e. Polish Lowlands, the Carpathians, the Carpathian Foredeep, and the PolishExclusive Economic Zone The resources were divided into anticipated economic, industrial, undeveloped resources and abandoneddeposits. In addition, the three Polish companies involved in the extraction of oil, namely PGNiG S.A., the LOTOS Group S.A. andORLEN Upstream sp. z o.o., were presented. The locations where exploitation is carried out and the volume of oil production in thelast few years were discussed.

Polyol and polyurethane foam from cellulose hydrolysate

AbstractBACKGROUNDAt present the majority of polyurethanes, including polyurethane foams (PUF), are obtained from petrochemical substrates. However, green chemistry policy worldwide and restricted crude oil resources are driving the use of biological substrates to make polyurethanes. Widely available cellulose seems to meet the expectation of a polyol substrate for use in synthesizing polyurethane foams provided that it is converted first into liquid resin with free hydroxyl groups.RESULTSCellulose hydrolysate was functionalized with glycidol and ethylene carbonate to obtain polyol. The product was characterized by infrared and proton nuclear magnetic resonance spectroscopy and matrix‐assisted laser desorption ionization–time‐of‐flight spectrometry. The polyol then was used to obtain rigid polyurethane foam. The foam was characterized by physicochemical methods to determine apparent density, water uptake and polymerization shrinkage.CONCLUSIONSNew polyol was obtained from cellulose hydrolysate by reaction with glycidol and ethylene carbonate in the presence of potassium carbonate as catalyst without solvent. This polyol contains hydroxyalkylated cellulose units incorporated into its structure and is suitable for synthesis of polyurethane foams. The properties of the foam were close to those of typical rigid polyuerethane foams used in industry. The foam showed good thermal resistance. Thermal exposure of obtained foam results in increase of compression strength. © 2020 Society of Chemical Industry (SCI)

Catalytic Aquathermolysis for Altering the Rheology of Asphaltic Crude Oil Using Ionic Liquid Modified Magnetic MWCNT

The use of asphaltic crude oil resources as an alternative to offset light oil supplies over the next years has attracted oil field attention. However, its high viscosity greatly impedes the production of asphaltic crude oil from wells and constitutes an obstacle, especially during transportation and refining operations. Thus, catalytic aquathermolysis has been introduced as an attractive and green technique for upgrading the asphaltic crude oil at elevated temperatures by reducing the asphaltic crude oil viscosity. In this study, magnetic multiwalled carbon nanotubes (MWCNTs) were prepared and modified with 1-ethyl-3-(3-formyl-4-hydroxybenzyl)-1H-imidazol-3-ium acetate (EFHIA). The results revealed the rheology results revealed that the viscosity of crude oil was reduced by 75.9% when compared to thermally treated blank at the same degree after 2 h of operation using Fe3O4/MWCNT@EFHIA as a catalyst. The asphaltene, resin, and sulfur measurements revealed that the percentages of these compounds were reduced to 37%, 43%, and 47%, respectively, upon using 0.2% Fe3O4/MWCNT@EFHIA as a catalyst at 200 °C for 2 h.

Rheological and Chemical Characteristics of Asphalt Binder Modified with Groundnut Shell Bio-oil

Abstract Increase in the asphalt binder prices, dwindling crude oil resources, and an enhanced obligation for environmentally sustainable asphalt binder necessitates the exploration of alternate avenues. One such promising approach is the adoption of bio-oil (BO) from biomasses for the production of asphalt binder. This study adopts BO derived from groundnut shell biomass (by fast pyrolysis) for modification of AC30. BO was incorporated in AC30 at varying dosages of 5, 10, and 15 % by weight. The tests performed included carbon, hydrogen, nitrogen, sulfur, and oxygen; Fourier transform infrared (FTIR) spectroscopy; absolute viscosity; softening point; dynamic viscosity; frequency sweep at multiple temperatures; performance grade (PG); multiple stress creep and recovery; and linear amplitude sweep. Both carbon, hydrogen, nitrogen, sulfur, and oxygen and FTIR analysis indicated that BO had caused alterations at the molecular level of AC30. An increase in absolute viscosity and softening point was observed up to a BO dosage of 10 %. Dynamic viscosity was observed to increase until 5 % BO dosage. BO dosages of 10 % and 15 % were observed to increase the high-temperature PG. However, the intermediate temperature grade increased for all BO dosages. Only 15 % BO dosage caused a compromise in the low-temperature PG. Nonrecoverable creep compliance was observed to decrease until the BO dosage of 10 %, indicating an enhancement in rutting resistance. Also, fatigue life was observed to enhance until 10 % BO dosage. Overall, the study indicated that groundnut shell BO can substantially improve the resistance to primary distresses of rutting, fatigue, and thermal cracking. Conclusively, a BO dosage of 10 % was observed to be the most favorable.

Nanoparticles as flow improver of petroleum crudes: Study on temperature-dependent steady-state and dynamic rheological behavior of crude oils

With the present energy scenario, the oil companies are persuading to exploit crude oil resources with high viscosity and an extreme chemical composition which makes production and transportation complex. The rheology of crude oil is related to the chemical components present in them where the molecular structure of polar polycyclic aromatic hydrocarbon (PAH) plays an important role. The emergence of nanotechnology in this aspect may provide a better solution for production optimization from the subsurface reservoir as well as flow assurance in surface transportation. The present study investigates the rheological behavior of two crude oils that are chemically different at the molecular level which is demonstrated by spectroscopic methods viz. UV–visible, Fluorescence and FTIR spectroscopy. Steady-state and dynamic rheological experiments carried out with nanoparticle-free and nanoparticles added crude oil clearly exhibits that at different temperature ranges, the nanoparticles help in improving the flow properties by modifying the viscoelastic-network. The silica nanoparticles produced a higher reduction in viscosity compared to alumina nanoparticles and showed different effects on the behavior of both the samples. Thus, nanoparticles could be an important agent for flow assurance, where the proper molecular-level characterization of crude oils would help in selecting the nanoparticles for better performance.

A Need for Investment in Nigerian Crude Oil Refining and Infrastructures: A Panacea to Refined Petroleum Shortages and Economic Growth

Despite the abundance of occurring natural crude oil resources, Nigeria continually suffers shortages of refined petroleum products, which undermines economic development of the country. The purpose of this multicase study was to explore the strategic role of how investment in petroleum refineries and infrastructures can improve supply and hence mitigate shortages or scarcity of refined petroleum products in the petroleum supply chain and enhance economic development in Nigeria. The research participants comprise of ten senior leaders from two private-sector Nigerian downstream petroleum supply companies located in the Niger Delta region, who had effectively implemented strategies for petroleum supply. The conceptual framework for the study was the resource based view theory. Data were collected through semistructured face-to-face interviews and review of operational and policy documents from the supply or marketing petroleum companies. Data were transcribed, analyzed, and validated through member checking and triangulation. The discoveries indicate the need to establish more refineries, privatize the existing moribund refineries, and build more infrastructures in Nigeria. Findings may be used by petroleum leaders and investors to optimize available crude oil natural resources, and to create investment strategies in the petroleum supply chain, leading to product availability, sustainability, poverty reduction, and economic development in Nigeria.

Hierarchical porous spinel MFe2O4 (M=Fe, Zn, Ni and Co) nanoparticles: Facile synthesis approach and their superb stability and catalytic performance in Fischer-Tropsch synthesis

The environmental pollution problem and the dwindling in the crude oil resources have been driving considerable researches into alternative routes for the production of clean and low cost liquid fuels. Fischer-Tropsch synthesis (FTS) is a key-technology and a clean alternative for the production of valuable organic chemicals and high standard liquid fuels through the reaction of syngas (CO/H2). In this study, one-pot hydrothermal reaction was adopted for the synthesis of robust MFe2O4 (M = Fe, Zn, Ni and Co) nanoparticles (NPs) with hierarchical porous-structured. The as-synthesized NPs and without the reported necessary pre-calcination step were appointed as robust catalysts in FTS at various reaction temperature (240–290 °C). The obtained catalytic results have demonstrated that CoFe2O4 NPs catalyst with its inversed spinel structure exhibited the optimum catalytic activity compared with the type of normal spinel structure of ZnFe2O4 catalyst. More precisely, CoFe2O4 NPs catalyst showed the best CO conversion ratio of 96% at 290 °C and the highest light-olefin (C2–C4) selectivity value of 63%. However, Fe3O4 NPs catalyst displayed the highest selectivity toward long chain hydrocarbon product (C5+) of 50 wt%, and the lowest CH4 selectivity value of 12% at 260 °C. Notably, the obtained results from X-ray diffraction and N2-physisorption characterization for the spent ferrite catalysts demonstrated that the co-existence of the active sites of Hägg iron carbide (χ-Fe5C2) and metallic Co phases and along with the high surface area and pore diameter plays the key role for the obtained high catalytic activity in CoFe2O4 NPs. Moreover, the produced catalysts in this study exhibited good stability performance within maintained high catalytic activity for a period of at least 700 h of industrial-relevant FTS conditions.

Impact of Agricultural Education on Students’ Career Choice: A Survey

Agriculture has become the bedrock of some growing economy in the world but the discovery of crude oil and other resources in a developing country like Nigeria has led to the extreme decline in the practice. Many youths now have either low or no interested in agriculture and the majority of the people that are actively practicing are the older generation.
 This study revisits the impact of education on students interest in agriculture as a professional career. The study was carried out in an agriculture-based uni-versity with a state of the art equipment. Our findings show that 64% of agricul-ture students who participated in this survey are willing to pursue agriculture-related careers. Likewise, there is a significant relationship between the student’s gender and farm ownership, with 84% of male students likelier to own farms. Also, our results have shown that students in higher levels have more interests in agriculture compared to students at lower levels and this invariably increases the possibilities of their pursuing agriculture-related careers or businesses.

Population Pressure on Land Resources in Nigeria: The Past and Projected Outcome

Aims: This paper assesses the population pressure on land resources in Nigeria: The past and projected outcome.
 Study Design: 1967 to 2068 time series data were used. The data sets were resorted to due to lack of complete national data.
 Place and Duration of Study: Past (1967-2017) and projected (2018-2068) five decades in Nigeria.
 Methodology: The time series data were obtained from the United Nations Population Division, Department of Economic and Social Affairs, National Population Commission, International Energy Statistics and Food and Agriculture Organization (FAO) on population levels, renewable and non renewable resources in Nigeria. Others such as transformity were adapted from Odum (1996) and Odum (2000) for specific objectives. Data collected were analyzed using modified ecological footprint/carrying capacity approach, descriptive statistics and Z-statistics.
 Results: Results showed that the mean annual pressure on land resources in the past five decades (1967-2017) was 9.323 hectares per capita, while the projected pressure in the next five decades (2018-2068) was 213.178 hectares per capita. Results also showed that about 73.08 percent of the pressure per capita in the past five decades emanated from arable land consumption (6.813ha), while 75.91percent of the pressure is expected to emanate from fossil land in the next projected five decades due to crude oil and mineral resource exploration and exploitation. The carrying capacity of land resources in the past five decades was 6.4091 hectares per capita, while that of the projected five decades was 1.667 hectares per capita, an indication of ecological overshoot in both periods.
 Conclusion: Population pressures on land resources per capita in the past and projected five decades are higher than the carrying capacity of these resources in the country. Citizens lived and are expected to live unsustainably by depleting and degrading available land resources. Arable land consumption is the major contributor to the total pressure on land resources in the past five decades, while the consumption of fossil land due to exploration and exploitation of crude oil and mineral resources is expected to contribute majorly to the total pressure on land resources in the next five decades. Limiting affluence (per capita consumption of resources) and improving technology will not only ensure sustainable use of arable and fossil lands but place consumption within the limits of these resources for a sustainable future.

What Strategies And Policies Can Save Nigeria in the Energy Transition?

The world is fast changing and so is the energy mix. A clarion call by scientists worldwide calls for immediate action to prevent the impact of climate change or face the consequences in the coming few years. Scientists and environmental activists are lobbying against the use of fossil-based fuel and mounting pressure on financial institutions and government to stop the financing of fossil fuel projects all over the world. The strategy is to dry-up investment from fossil fuel energy, then more investment will flow towards the greener alternatives in the next two decades to support the development of new technologies and other earth-friendly energy sources. Also, by clamouring for change, the cleaner technologies and alternative (greener) energy will create a substantial fall in the demand of fossil fuel, particularly crude oil. However, this move poses existential threat to third-world countries like Nigeria which is largely dependent on sales royalties and tax revenues from crude oil and natural gas reserves respectively. The future trends warn of a looming dooms day approaching when the remaining oil may not be able to attract foreign money for its development. Nigeria must therefore hasten in the effort to recover its reserves timeously and make the most of what it has before the green era. Since joining Organization of Petroleum Exporting Countries (OPEC) in 1971, Nigeria has established is membership status by steadily growing its reserves to now over 41 billion barrels of crude oil that is yet untapped mainly attributed to the Niger Delta basin. This means that Nigeria’s crude oil export is controlled by OPEC but this restriction does not apply to the export of Nigerian petroleum products. Hence, with investment into refineries and downstream value chain, Nigeria can afford to increase its production to maximize its resources and grow enormous wealth. Most of the other Nigerian petroleum basins in Nigeria are still under-explored and as such not accounted for in the nation’s wealth of resources. It is believed the nation can also benefit from significant amount of oil discoveries that are either invisible to conventional technologies or bypassed by natural recovery mechanisms. These presents an opportunity to uplift the nation’s reserves without risky investment in deep water exploration. Nigeria should aim to ramp up its production rapidly in the next couple of years to harness its available resources while there is still time to do so. To take advantage of Nigeria’s vast oil resources, the government must explore strategic policies that will enhance its exploration and development interests through the expansion of value chain and promote alternative energy. It must also exploit the remaining reserves quickly. Therefore, Nigeria must take advantage of its crude oil resources by exploring various fiscal incentives and take key regulatory steps to ensure that production is maximized to drain the technically recoverable reserves as quickly as possible. The wind fall from this can then be ploughed into the economy to develop value chain and also promote transition to greener energy alternative. To achieve this, a radical policy change is necessary such as incentivizing oil production and encouraging oil companies to change their direction. This paper presents some thought-provoking ideas of how this can be achieved in the near term.

Smart Solutions for Oil and Gas industry Challenges

Crude oil is the most attractive source of energy. It is formed at high temperatures and pressures deep down in the earth. Extraction of this energy resource involves expensive drilling and extraction processes. The composition and physical characteristics of the oil depend on the source of the organic material, temperature, and heat. The greater the viscosity of the oil the more difficult it is to extract. Heavy oil, is the name given to oil with API gravity between 10 and 20, and high viscosity <10,000 cP. It is technologically challenging and expensive to extract. Many solutions have been explored owing to the high financial returns in this business. In this study, we propose new smart solutions, utilizing unique properties of nanoparticles of different shapes and sizes to reduce the viscosity of heavy oil to make it easier to extract. Nanoparticles are 1- 100nm in size, have a high surface-to-volume ratio, high heat capacity, excellent heat conductivity, low thermal expansion, and high melting temperatures. A combination of some of these properties was utilized to explore solutions for drilling and heavy oil viscosity problems. In drilling, problems like pipe sticking lost fluid circulation, formation damage, erosion of the borehole, thermal instability of drilling fluids, and their insufficient gel properties, lie in controlling and optimizing the rheology of the drilling fluid. Therefore, to advance the performance of water-based drilling fluids in such harsh reservoir conditions, a simple treatment based on nanotechnology was utilized by synthesizing in-house nano-additives. 1-3 wt% of nano-additives increases fluid density by~5% and dynamic viscosity by-20% and reduces fluid loss by 50%. In addition to this, it forms a thin smooth Mud Cake with the surroundings of the formation. At ambient temperatures, crude oil and bitumen are resistant to flow through reservoir rock because of their high viscosities. Consequently, the energy expended to produce and upgrade a barrel of oil can be as high as 40% of the total energy available from the crude oil resource. Thermally enhanced oil recovery techniques such as steam-assisted recovery and also in situ combustions are employed to upgrade and save the physicochemical properties of the oil. All these recovery techniques are expensive, complicated, and need periodic maintenance; therefore, direct and cheap solutions are the main targets for high in situ upgrading. Our study provides an alternative method that can help in the production and upgrading of such heavy oil by cracking it. For the heavy oil cracking process, iron oxide Nano-Rods (IONRs) were synthesized by an environmentally friendly method. These rods were embedded and well mixed with 1 L of heavy oil (12 API) and subjected to direct microwave radiation. The radiation causes a reduction in the dynamic viscosity of crude oil due to the presence of dipole water molecules. This reduction increased up to 50% when a controlled amount of IONRs additives were added at the same temperature.

Improved Water Injection Index Curve on Estimation of Oil in Place for Fractured Vuggy Carbonate Reservoirs

Fractured vuggy carbonate reservoirs play an important role in the world crude oil resources. The significant reservoir heterogeneity represented by complex distribution of multi-scale fractures and vugs brings challenges to reservoir oil in place (OIP) estimation, which is a fundamental parameter in oil field development. OIP estimation based on production dynamic analysis is regularly carried out in oilfield practice, the result of which is normally adopted as a comparison to volumetric calculation from geological study for mutual verification. This paper introduces a widely used water injection index curve method on OIP estimation of fractured vuggy carbonate reservoir in Tarim oilfield, which is a straight forward plot of bottom-hole pressure versus cumulative water injection. An improved model taking into consideration the compressibility of second gas gap is presented and applied on real well from Tahe carbonate reservoir. The application of the new model demonstrated that conventional method tends to over-estimate the OIP, while the improved model gives a relatively reliable estimation. The improved water injection index curve in this paper is easy to be conducted based on well production and injection dynamic and shows advantages on convenient pressure conversion from well-head to well-bottom and avoiding dealing with the high uncertainty of aquifers in carbonate reservoir.

Rheological-microstructural evaluations of the short and long-term aged asphalt binders through relaxation spectra determination

Asphalt binders from three main crude oil resources are evaluated through the mechanical and chemical tests. The generalized sigmoidal function and William-Landel-Ferry shifting equation are suitable for the unaged and aged binders in constructing master curves. The relaxation spectra of the aged binders show the increased widths. The molecular weight distributions and mean molecular sizes of binders are derived only from the dynamic mechanical analysis data through the relaxation spectra determination. In addition, the zero shear viscosities (ZSVs) and activation energy of the binders are accurately calculated from the relaxation spectra. Linear regression relations between ZSVs and molecular weights exhibit satisfactory fittings for all binders. Moreover, the mean molecular sizes of unaged and aged binders are found to be stable. The results indicate that large scale molecules get larger, while the small scale molecules as saturates get smaller to balance the mean size distribution under the short- and long-term ageing.

Assortment analysis of shutter valves for spark ignition engines timing systems

Continually tightened emission restrictions together with limited crude oil resources are factors driving more efficient fuel management strategies implementation. Such operations results in increase of internal combustion engine efficiency due to change in geometry and materials of existing systems as well as introducing new solutions. Over the years many approaches were taken. One of them was timing valve geometry optimization, which in case of conventional poppet valves is burden with number of restrictions. At this place some nonconventional designs might be introduced and one of them is so called shutter valve. Construction of shutter valve finds its roots in photographic industry where it is commonly used for exposition of photosensitive material for exactly determined period, enforcing very fast operation of mechanism similar like in case of valve train, which makes it suitable to adapt in engine timing system.