Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 37
items per page: 25 50 75
Sort by:

Abstract

Fatty acids are very important biological substances due to their metabolic, structural and signal- ing functions. Omega-3 has different beneficial, harmful and neutral effects on adipokines. Adi- pokines have autocrine, paracrine and endocrine effects on metabolism. In the study 54 German Fawn x Hair crossbred goats were synchronized using intravaginal sponges. During the first pe- riod (mating-75 days), all animals were fed a diet supplemented with protected fat and during the second period of pregnancy (76 days-kidding), one of the groups was fed a diet supplemented with fish oil and other was fed a diet supplemented with protected fat. Serum leptin, ghrelin, adi- ponektin and omentin levels were measured by ELISA system. Distributed fed (roughage and concentrate) were sampled and dry matter, crude protein, fat, and ash were determined by AOAC (1988) analysis methods. The Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) analysis were conducted using heat stable α-amylase and sodium sulphite. Fat source (fish oil or protected fat) affected feed consumption and the highest feed consumption was found in the group fed with protected oil first half of the pregnancy and with fish oil in the second half of the pregnancy and in the fish oil group during the pregnancy. It was determined that the use of fish oil during pregnancy did not affect ghrelin, leptin and omentin concentrations in serum. Adipokine levels of fish oil fed animals during any period of pregnancy were found to be high and it was also found that serum adiponectin levels in goats fed with diet containing fish oil in the first half of pregnancy and protected fat in the second half were statistically significantly high in adipokines.
Go to article

Abstract

The aim of this study was to investigate interactions between conventional antifungal drug and essential oils against isolates of Malassezia pachydermatis. Antifungal activity of Cinnamomum cassia, Melaleuca alternifolia, Mentha piperita, Origanum vulgare and Syzygium aromaticum essential oils were tested against 19 strains of M. pachydermatis isolated from healthy dogs and reference strain M. pachydermatis CBS 1879. The checkerboard assay was used to search for in- teractions. Synergism was observed for the combination of clotrimazole with Melaleuca alternifolia essential oil, Mentha piperita and Origanum vulgare. The combinations of Cinnamomum cassia and Syzygium aromaticum essential oils with clotrimazole showed indifferent effect. Additive antimicrobial activity was observed for the combination of clotrimazole with Syzygium aromaticum and Melaleuca alternifolia essential oils against reference strain. The obtained results showed synergistic interactions between essential oils and clotrimazole which could improve effectiveness of this antifungal drug.
Go to article

Abstract

The article presents a synthetic analysis of the crude oil market in Poland. As of today, this safety is provided mainly on the basis of native lignite and hard coal resources. However, the analysis of the hard coal market conducted by the authors indicates that the carried out mining restructuring (among others) led to an excessive reduction of mining volume and employment level in the hard coal mining sector. This led to a precedent situation when Poland became an importer of this energy carrier. In addition, the European Union’s requirements for greenhouse gas emissions must be taken into account. In connection with the above, it is necessary to search for new energy sources or technologies that enable hard coal to meet the requirements. It is possible to apply the so-called clean coal technologies that allow the greenhouse gas emissions generated during coal combustion to be reduced. As of today, they are not used on a mass scale, because the use of this type of technology involves additional financial expenses. However, taking into account that technologies have been growing faster and faster, are modernized in a shorter time, making a breakthrough discovery took hundreds of years, now it is often a few months, clean coal technologies can become the optimal solution in the near future. It is also necessary to diversify the sources of obtaining imported energy carriers. The article describes coal and crude oil in terms of their mutual substitution. The article is a continuation of research conducted by the authors. Previous publications presented considerations on analogous topics related to natural gas and renewable energy sources. The crude oil market in Poland was analyzed and forecasts for oil extraction and the demand in the world and Poland by 2023 were presented. The SARIMA model was also created. The model made it possible to obtain oil an prices forecast.
Go to article

Abstract

Concentration and dispersion distributions of mineral suspension and crude-oil particles in waters of the Kongsfiord (Spitsbergen) were examined in 1997. Most suspension occurs at glacier margins and decreases towards a fiord outlet.
Go to article

Abstract

This work presents the methodology for analyzing the impact of ground vibrations induced during the drilling of gas/oil exploration wells on the surrounding constructions, as well as on humans and the natural environment. In the primary stage, this methodology is based on measurements of ground vibrations induced by a specific type of drilling system in the so-called reference site. In the next stage, ground vibrations are estimated in similar conditions to another design site, these conditions are assumed for a given drilling system, treated as a vibration source. In both sites, special seismic and geotechnical data are collected to construct numerical models for dynamic analyses. Finally, if it is required, a protection system is proposed with respect to the drilling technology and local conditions. The methodology presented has been tested on the terrain of an active natural gas mine used as the design site, and located in the southeastern part of Poland. The reference site was placed in the terrain of a working drilling system in similar conditions in the central part of Poland. Based on the results of numerical simulations, one may verify the different locations of the drilling rig in the design site with respect to the existing industrial structure. Due to the hazard from destructive ground vibrations, a certain vibroisolation system was proposed at the design site. Based on the results of numerical simulations one could rearrange the components of the drilling system in order to provide maximum security for the surrounding structures.
Go to article

Abstract

A ccording to the Polish Geological and Mining Law the granting of a concession for the exploration of a hydrocarbon deposit and the production of hydrocarbons from a deposit, or a concession for the production of hydrocarbons from a deposit in Poland is proceeded according to a tender procedure or open door procedure (upon a request of an entity). O n June 28, 2018 the Polish Minister of the Environment announced 5 tender areas. These areas (promising for discoveries of conventional and unconventional oil and gas deposits) were selected by the geologists of the Polish Geological Institute-NRI and Department of Geology and Geological Concessions of the Ministry of the Environment based on the geological data resources stored in the National Geological Archive. These are: Bestwina-Czechowice, Królówka, Pyrzyce, Złoczew i Żabowo. The main exploration target on the areas located in central and north-western Poland (Pyrzyce, Żabowo and Złoczew) is related to Permian Rotliegend sandstones and carbonates of the Zechstein/Main Dolomite. The Bestwina-Czechowice and Królówka areas (southern Poland) are prospective for conventional and hybrid-type accumulations of gas in the Miocene of the Carpathian Foredeep below the Carpathian Overthrust and in the Paleozoic-Mesozoic basement. The beginning of the 4th bidding round for hydrocarbon concessions is planned in Q4 2019. The entity can also choose the area and apply for a license submitting an application to the Ministry of the Environment. The area indicated by the entity cannot be the subject of a tender or any other concession, and the maximum acreage is 1,200 km2.
Go to article

Abstract

The aim of the paper is to identify which factors influence the production of crude oil in Africa and what it means for the investments in oil production on this continent in the future. In order to identify these factors it is necessary to create a function of production. A number of variables have been chosen, which are likely to have an influence on the level of exploitation, such as the price of oil, oil consumption in Africa, oil import by the US, etc. The estimation of the function was based on the statistical analysis of empirical data. For the years 1980–2015 the linear regression model was estimated using the method of ordinary least squares (OLS) and econometric software – GRETL. In order to find the best model the academic research on the global oil market has been taken into account and a variety of statistical and econometric tests have been made. According to the literature on the subject, the production of crude oil in Africa is mostly affected by two players – Europe and the US. The first includes the member states of the OPEC. There are also countries of West Africa which in the past exported most of their production to the US. The model shows that the situation has changed after the “shale revolution”, which reduced the level of imported oil and consequently the level of African production. Moreover, an interesting trend has been noticed, namely that when oil prices go up, the oil production in Africa decreases. The reason for this phenomenon is that high oil prices make American shale plays more profitable than West African petroleum basins. The model aggregating macroeconomic indicators and statistics is a very useful management tool and it reveals the problems of the efficiency of investments in oil production in Africa.
Go to article

Abstract

In this study, rubber seed/shea butter oil was used to formulate core oil. The formulated core oil was characterised. D-optimal mixture design was used for multi response optimisation of the functional properties of rubber seed-shea butter coil oil. Desirable values for some responses might be obtained from a factor combination while for others responses not so desirable values. Through multiple response optimisations, a factor setting that gives the desirable values for all responses was obtained. The selected optimum mixture setting for the formulated core oil is 65.937% Rubber seed and 34.063% Shea butter oil at desirability of 0.924. Under the optimum condition the functional properties of the core oil was found to be 39.57KN/M2, 626.85KN/M2, 36.63KN/M2, 593.906KN/M2, 412.605 and 167.309s for Green Compressive Strength, Dry Compressive Strength, Green Tensile Strength, Dry Tensile Strength, Permeability and Collapsibility respectively. The optimum conditions were validated with less than 0.2% error. The functional properties of the formulated core oil was compared to the functional properties of linseed core oil. It was found that rubber seed-shea butter core oil can be used for producing cores suitable for Aluminium casting.
Go to article

Abstract

Polychlorinated biphenyls (PCBs) are one group of persistent organic pollutants (POPs) that are of international concern because of global distribution, persistence, and toxicity. Removal of these compounds from the environment remains a very difficult challenge because the compounds are highly hydrophobic and have very low solubility in water. A 900 W domestic microwave oven, pyrex vessel reactor, pyrex tube connector and condensing system were used in this experiment. Radiation was discontinuous and ray powers were 540, 720 and 900 W. The PCBS were analyzed by GC-ECD. The application of microwave radiation and H2O2/TiO2 agents for the degradation of polychlorinated biphenyl contaminated oil was explored in this study. PCB – contaminated oil was treated in a pyrex reactor by microwave irradiation at 2450 MHz with the addition of H2O2/TiO2. A novel grain TiO2 (GT01) was used. The determination of PCB residues in oil by gas chromatography (GC) revealed that rates of PCB decomposition were highly dependent on microwave power, exposure time, ratio to solvent with transformer oil in 3:1, the optimal amount of GT01 (0.2 g) and 0.116 mol of H2O2 were used in the study. It was suggested that microwave irradiation with the assistance of H2O2/TiO2 might be a potential technology for the degradation of PCB – contaminated oil. The experiments show that MW irradiation, H2O2 oxidant and TiO2 catalyst lead to a degradation efficiency of PCBs only in the presence of ethanol. The results showed that the addition of ethanol significantly enhanced degradation efficiency of PCBs.
Go to article

Abstract

A verification study of ultrasound transmission numerical simulation results with experiment results is presented in this paper. The work considers a model of a transformer tank which is filled with electro insulating oil. In the experiment, performed under laboratory conditions, an ultrasound wave is generated by a piezoelectric transducer that is fixed in the centre of the tank and measured by another transducer mounted inside the tank at three distances: 10, 20 and 30 cm from the sound source. The transducer is able to measure and generate acoustic waves in the ultrasound frequency band up to 1 MHz. The simulation considers numerical calculation of acoustic pressure distribution inside the tank in which acoustic source emits waves with frequency equal to 100 kHz. Verification analysis has confirmed consistency of the numerically calculated values with the measurement results.
Go to article

Abstract

The aim of the work was to estimate the influence of plants mycorrhizas on the number of hydrocarbons degrading bacteria, saprophytic bacteria and molds fungi during the remediation of the soil samples contaminated with used engine oil. The investigation were carried out in laboratory conditions. Nine modifications of the soil substrate were prepared and divided into three groups: the first one - without used engine oil; the second one - with 10% (w/w) of used engine oil; the third one - with 25% (w/w) of used oil. In each group one sample was sown with ribwort, one was inoculated with living spores of mycorrhizal fungi and sown with ribwort, and the third one was left without plants and mycorrhizal fungi. The sample of the uncontaminated soil was the control. The investigation showed a significant effect of used engine oil, the presence of ribwort and mycorrhizal fungi on the number of soil microorganisms. The increase of the number of hydrocarbons degrading bacteria, in respect to the control sample was observed in the used engine oil contaminated samples. The seeding of soil samples with plants and additional inoculation with spores of mycorrhizal fungi stimulated the increase of the number of microorganisms in the all studied groups.
Go to article

Abstract

The aim of the study was to determine the impact of various methods of oil mixing with wastewater on properties of synthetic municipal wastewater containing edible oil (SMW+0.02% m/v rapeseed oil). The study was carried out in 3L glass, cylindrical reactors to which SMW+0.02% were introduced. Various methods of its mixing with water were applied: mechanical mixing (SMW+0.02%+mixing) and sonication (SMW+0.02%+ultrasounds). The wastewater was sonicated at 35 kHz for 30 min. The constant temperature conditions were maintained during the experiment for each mixing method (15°C, 20°C and 30°C). The analysis of parameters (pH, COD, BOD5 and long chain free fatty acids concentration) of raw wastewater and after 2, 4, 6, 24, 48 and 72 hours of inoculation was performed to determine the effect of mixing method. The most signifi cant changes in wastewater chemical parameters after the introduction of the oil were observed in the case of COD. For SMW+0.02%+ mixing a slow increase in COD within 24 hours of the process was observed. In the case of SMW+0.02%+ultrasounds the increase and the decrease of COD value were observed in reference to the initial value. The changes in acids concentrations observed in reactors with SMW+0.02%+ultrasounds were referred to the ones observed in reactors with SMW+0.02%+mixing but changes were more intense in the fi rst reactor. The use of ultrasounds in pre-treatment of wastewater resulted in the intense appearance of palmitic acid for 6 hours. Regardless of the emulsion formation method (mixing or ultrasounds), the concentration of oleic acid and linoleic acid was reduced. The biggest changes in free fatty acids concentration were observed for palmitic, oleic and linoleic acids after 24 hours.
Go to article

Abstract

The article compares the management of energy resources in Poland and Ukraine over the period 2000–2017. The analysis took changes in the volume of coal, oil and natural gas resources into consideration. The indicators of supplies of these fuels for Poland and Ukraine have additionally been compared with selected EU countries. In order to assess energy security of Poland and Ukraine, the changes in the primary energy consumption have been analyzed in general in first order, then the possibilities of meeting the demand for natural gas, coal and oil have been determined based on the domestic extraction of individual energy resources. Such a comparison indicates the dominant role of coal in Poland while the extraction of oil and natural gas meets the domestic demand to a greater extent in Ukraine. Over the period 2000-2017, trends in primary energy consumption were different; a 17% increase was noted in Poland, while a nearly 40% decline was noted in Ukraine. The main factors responsible for radical changes in fuel and energy management in Ukraine have been identified: military operations in the east of the country and the annexation of Crimea, demographic changes. These events had a negative impact especially on the volume of hard coal mining in Ukraine; the significant increase in imports from 5.36 to 19.14 million tons in 2011-2017 was necessary for balancing. The balance of foreign exchange for electricity was also compared. Over the past years, this comparison has been favorable for Ukraine, where the dominance of electricity exports over imports is noticeable, which generated revenues of over USD 200 million in 2017.
Go to article

Abstract

The events that took place on April 10,2010 on the Gulf of Mexico began an international debate on minimizing and materializing the risk of dangerous occurrences and accidents during the exploitation of offshore energy resources. In the aftermath of this event to ensure safe operation in European maritime areas, the European Union decided to introduce regulations throughout the entire EU. On June 12, 2013, Directive 2013/30/EU of the European Parliament and of the Council on safety of offshore oil and gas operations and amending Directive 2004/35/EC was issued. The main aim of the Directive is to reduce the occurrence of major accidents relating to offshore oil and gas operations and limits their consequences. The article is a review of provision of Directive 2013/30/UE with particular regard to requirements at the national level. What is more, the paper indicates solutions which must be introduced by July 19, 2018 in offshore companies. The incorporated solutions must include the protection of the marine environment against pollutions (especially oil spills), establish minimum conditions for safe offshore exploration and the production of oil and gas and improve the response mechanism in the eventof an accident. The paper also presents accidents which take place in oil and gas fields which are a background of necessary improvements of safety during offshore operations.
Go to article

Abstract

This article aims to discuss the notion of environmental damage under the CLC 1992 and FUND 1992 as stated in the new Guidelines for Presenting Claims for Environmental Damage prepared by the International Oil Pollution Compensation Funds. That approach is contrasted with the solution adopted in the United States of America under the OPA. Particular attention is given to the problems of compensation for lost services of the environment, as well as providing alternative environment as a restoration measure. The judgments of French and Spanish courts in the Erika and Prestige cases are discussed, raising questions as to suitability of the CLC 1992/FUND 1992 system.
Go to article

Abstract

In this paper distortion of surface topography measurement results by improper selection of the reference plane is taken into consideration. The following types of surfaces from cylindrical elements were analyzed: cylinder liners after plateau honing, cylinder liners with additionally burnished oil pockets and turned piston skirts. Surface topographies of these elements after a low wear process were also studied. In order to obtain areal surface topography parameters, the form was eliminated using cylinders and polynomials of the following degrees: 2, 3, 4, 6, 8, 10 and 12. Parameters of surfaces after form removal were compared. After analysis of results the reference elements for each kind of surface were recommended. A special procedure was proposed in order to select the degree of a polynomial. This method is based on surface topography changes with increase of polynomial degree. The effect of improper form elimination on measuring uncertainty was studied.
Go to article

Abstract

The results of pyrolysis of pine chips and refuse derived fuel fractions are presented. The experiments were carried out in a pilot pyrolysis reactor. The feedstock was analyzed by an elemental analyzer and the X-ray fluorescence spectrometer to determine the elemental composition. To find out optimum conditions for pyrolysis and mass loss as a function of temperature the thermogravimetric analysis was applied. Gases from the thermogravimetric analysis were directed to the infrared spectrometer using gas-flow cuvette to online analysis of gas composition. Chemical composition of the produced gas was measured using gas chromatography with a thermal conductivity detector and a flame ionization detector. The product analysis also took into account the mass balance of individual products.
Go to article

Abstract

In this paper, the properties of AE signals originating from phenomena occurring during magnetization of ferromagnetic materials which are used to construct power transformer cores are presented. The AE signals in a selected power oil transformer were recorded and analyzed. The analysis included, i.e., time, frequency, and time-frequency analyses, calculations of amplitude distributions of the signals and defined AE descriptors, determination of the descriptor map on the side walls of transformers, as well as a detailed analysis of selected part of the signals. The maps of descriptors were analyzed in the frequency bands of 20–70 kHz, 70–100 kHz, and 100–200 kHz. The analysis of the properties of the signals was performed in time and frequency domains. Based on the analysis, there were identified the AE signals originating from the phenomena occurring during the core magnetization of a power oil transformer. To identify those phenomena, the maps of the ADC descriptor calculated in the band of 20–70 kHz when selecting the measurement points in which there were no AE sources from partial discharges were used. An analysis of magnetoacoustic emission signals in the bands of 70–100 kHz and 100–200 kHz was also performed. The analysis of the signal properties in such an extended frequency range allowed determining the properties of the magnetoacoustic signals coming from core sheets of power oil transformers.
Go to article

Abstract

In order for the working status of the aluminum alloyed hydraulic valve body to be controlled in actual conditions, a new friction and wear design device was designed for the cast iron and aluminum alloyed valve bodies comparison under the same conditions. The results displayed that: (1) The oil leakage of the aluminum alloyed hydraulic valve body was higher than the corresponding oil leakage of the iron body during the initial running stage. Besides during a later running stage, the oil leakage of the aluminum alloyed body was lower than corresponding oil leakage of the iron body; (2) The actual oil leakage of different materials consisted of two parts: the foundation leakage that was the leakage of the valve without wear and wear leakage that was caused by the worn valve body; (3) The aluminum alloyed valve could rely on the dust filling furrow and melting mechanism that led the body surface to retain dynamic balance, resulting in the valve leakage preservation at a low level. The aluminum alloy modified valve body can meet the requirements of hydraulic leakage under pressure, possibly constituting this alloy suitable for hydraulic valve body manufacturing.
Go to article

Abstract

This study is aimed at measuring the effect of pig, cow, horse and poultry manures on the degradation of selected Polycyclic Aromatics Hydrocarbons present in oil sludge. Four kilograms of soil amended with 1.2 kg of oil sludge was mixed with wood chips in a ratio of 1:2 (w:v) soil mixture: wood chips. The mixture was divided into fi ve parts and four parts were separately mixed with pig, cow, horse or poultry manures in a ratio of 2:1 (w:w) and the fi fth portion was used as the control with no manure added. All experiments were incubated for 10 months at room temperature. Compost piles were turned weekly for aeration and moisture level was maintained by adding deionised water enough to prevent the compost from getting dry. Moisture level, pH, temperature, CO2 evolution and oxygen consumption were measured monthly and the ash content of the compost at the end of experimentation. Highest temperature reached was 27.5°C in all compost heaps, pH ranged from 5.5 to 7.8 and CO2 evolution was highest in poultry manure at 18.78 μg/dwt/day. Microbial growth and activities were enhanced as indicated by increase in temperature, moisture level, pH value and respiration rate in all the compost piles. Bacteria capable of utilizing PAHs were isolated, purifi ed and characterized by molecular techniques using polymerase chain reaction with specifi c universal primers and the amplicons were sequenced. Bacteria identifi ed were Bacillus, Arthrobacter and Staphylococcus species. Percentage reduction in PAHs was measured using automated soxhlet extractor with Dichloromethane and gas chromatography/mass spectrometry. Results from PAH concentration measurements showed reduction of between 77% and 99%. Co- -composting of contaminated soil with animal manures enhanced the reduction in PAHs.
Go to article

Abstract

New York Bay is one of the most important transition regions of ships trading to east America. The region plays an important role in the commerce of the New York metropolitan area. The area is surrounded with the coasts that have various levels of environmental sensitivity. The area accommodates high diversity of native ecosystems and species that are rather vulnerable in case of oil spill. Thus getting well informed about the likelihood, or fate, of oil spills around this region is of great importance so that proactive measures can be taken. The purpose of this study is to investigate the oil spill and predict the future accidents likely to be encountered around the Bay of New York. Two trajectory models have been conducted for the study. ADIOS (Automated Data Inquiry for Oil Spills), has been conducted for natural degradation calculations, and, GNOME (General NOAA Operational Modeling Environment), has been conducted for surface spread simulation. The results gained through these efforts are hoped to be useful for many organizations dealing with oil spill response operations and contribute to an effective and efficient coordination among the relevant institutions.
Go to article

Abstract

Compounds present in oil sludge such as polycyclic aromatic hydrocarbons (PAHs) are known to be cytotoxic, mutagenic and potentially carcinogenic. Microorganisms including bacteria and fungi have been reported to degrade oil sludge components to innocuous compounds such as carbon dioxide, water and salts. In the present study, we isolated different bacteria with PAH-degrading capabilities from compost prepared from oil sludge and animal manures. These bacteria were isolated on a mineral base medium and mineral salt agar plates. A total of 31 morphologically distinct isolates were carefully selected from 5 different compost treatments for identification using polymerase chain reaction (PCR) of the 16S rRNA gene with specific primers (universal forward 16S-P1 PCR and reverse 16S-P2 PCR). The amplicons were sequenced and sequences were compared with the known nucleotides from the GenBank. The phylogenetic analyses of the isolates showed that they belong to 3 different clades; Firmicutes, Proteobacteria and Actinobacteria. These bacteria identified were closely related to the genera Bacillus, Arthrobacter, Staphylococcus, Brevibacterium, Variovorax, Paenibacillus, Ralstonia and Geobacillus. The results showed that Bacillus species were predominant in all composts. Based on the results of the degradation of the PAHs in the composts and results of previous studies on bacterial degradation of hydrocarbons in oil, the characteristics of these bacterial isolates suggests that they may be responsible for the breakdown of PAHs of different molecular weights in the composts. Thus, they may be potentially useful for bioremediation of oil sludge during compost bioremediation.
Go to article

Abstract

The aim of the study is to discuss the relationship of the crude oil price, speculative activity and fundamental factors. An empirical study was conducted with a VEC model. Two cointegrating vectors were identified. The first vector represents the speculative activity. We argue that the number of short non-commercial positions increases with the crude oil stock and price, decreases with the higher number of long non-commercial positions. A positive trend of crude oil prices may be a signal for traders outside the industry to invest in the oil market, especially as access to information could be limited for them. The second vector represents the crude oil price under the fundamental approach. The results support the hypothesis that the crude oil price is dependent on futures trading. The higher is a number of commercial long positions, the greater is the pressure on crude oil price to increase.
Go to article

This page uses 'cookies'. Learn more