35 research outputs found

    Surface inorganic scale formation in oil and gas industry: As adhesion and deposition processes

    Get PDF
    Scale formation on surfaces can normally be divided into two distinct processes: a “deposition process” which refers to the process of heterogeneous nucleation and growth at the asperities of the surface and an “adhesion process” which refers to the sticking of pre-existing crystals, which have nucleated in the bulk solution, and which build up as a layer on the surface. It has been presented in this paper that the surface scale formation rate is more dominantly controlled by the “deposition process” rather than the “adhesion process”. However, the level of agitation could have inverse effects on one process to another. Only a small amount of research has been done to understand the differences of the kinetics of each of these processes. The presented work represents an experimental study of scaling tests to assess the effect of hydrodynamic conditions, using Rotating Cylinder Electrode (RCE), in a complex scaling environment, particularly supersaturated with barium/strontium sulphate and calcium carbonate, on the stainless steel substrate coated with a wide range of different industrial coatings. In addition, the effect of the surface energy and surface roughness on both processes has been studied. The paper provides data that will assist in the understanding of the controlling parameters in scale formation in different conditions, and also describes what characteristics of the surface can make it a good anti-scale surface for inorganic scale; however, the results have showed that merely one parameter cannot assure a surface as a good antifouling surface

    Demographic risk factors of suicide in savojbolagh city of Tehran province: 2007-2009

    No full text
    Suicide is an important public health difficulty and the third leading cause of death among young population. This study examines some of the demographic risk factors of suicidal behaviors in Savojbolagh city. In a retrospective, descriptive, and cross-sectional study, suicidal behaviors from March 2007 to March 2009 in Savojbolagh city were investigated. A unified questionnaire was designed in mental health research centre for data gathering. A total of 892 suicidal behavior reports were collected from the health facilities. Suicide attempts were more frequent in females, young people, the married, high school graduates, and housewives. The most common motive for suicide attempt was interpersonal quarrels and secondly, economical problems. Completed (fatal) suicide was higher in males, older people, and unemployed subjects. Demographic risk factors in any region or country are dependent upon the local factors such as socioeconomic status and cultural beliefs which need to be considered in suicide prevention planning. © Kamla-Raj 2013

    Assessing surface engineering solutions for oilfield scale; correlating laboratory tests to field trials

    No full text
    Mineral scale deposition on surfaces of oil production equipment has been recognised as a major flow assurance problem. Most of the mineral scale deposition work published has solely focused on laboratory experiments and very little data are available that demonstrate such results are relevant and can be scaled-up to field environments. The current study focuses on mineral scale formation on surfaces and compares laboratory results with field data. A field test has been running for half a year on commercially-coated pipe spools along with uncoated ones. The different pipe sections were positioned along a water line injection system in an oilfield. In the laboratory, a standard bulk jar test was used and the ability of a range of chemically and morphologically modified coatings to prevent/reduce mineral scale surface fouling were assessed under different flow conditions (ranging from laminar to turbulent flow). The current study shows that if properly selected, surface engineering offers great promise as an approach to prevent mineral scale deposition in the piping system of oilfields

    Scale deposition in the oil and gas industry: From a systematic experimental scale study to real-Time field data

    No full text
    Flow reduction due to scale deposition within the downhole utilities, valve applications, and tubular is recognised as one the major flow assurance problems affecting production in the oil and gas sector. Most of the literatures investigating similar mineral fouling mechanism mainly focused on either a laboratory framework under well controlled conditions or from field conditions with no systematic investigations. The current work bridges between a systematic experimental scale study and field data. The experimental work encompasses an investigation into the effect of the hydrodynamic conditions on the rate of the scale deposits on modified surfaces in a complex scaling environment, where the brine compositions are derived from the field conditions; and the field data includes the rate of scale deposition on the modified surfaces inside the tubing from the formation water. The comparison of these two sets of results facilitates a better understanding of the controlling parameters in scaling formation in both laboratory conditions and field conditions

    Variation in chemical components and biological activity of Pterocarya fraxinifolia Lam. stems at different developmental stages

    No full text
    Background and objectives: Pterocarya fraxinifolia Lam. is a deciduous, fast-growing tree from walnut family. The stem barks and fruits of the plant have been used as diaphoretic in traditional medicine. Variation in the quantity and quality of the essential oil and extract of stems of the plant at different developmental stages was evaluated in addition to assessing the antimicrobial, cytotoxic and radical scavenging activities in the present study. Methods: Different developmental stages of the plant’s stem (i.e. vegetative, flowering, immature fruit and mature fruit) were subjected to hydro-distillation for obtaining the essential oil. The methanol extract of the samples was obtained by Soxhlet apparatus. Chemical composition of the oils was analyzed by gas chromatography/mass spectroscopy (GC/MS). Antimicrobial activity of the oils and extracts were determined against three Gram-positive and five Gram-negative bacteria and two fungi by disc diffusion method. Antioxidant activity of the samples was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene assays. Total phenolics content of extracts was determined using Folin-Ciocalteau reagent and cytotoxic effect was determined by brine shrimp lethality bioassay. Results: Hexadecanoic acid was one of the major components in all essential oil samples. All samples showed good antimicrobial activity against tested strains. Antioxidant activity of the extracts was comparable to the synthetic standard (butylated hydroxytoluene). The highest total phenolic content and cytotoxic effect were detected for the mature fruit stage of the plant extract and essential oil, respectively. Conclusion: Showing considerable antioxidant and cytotoxic effects, suggested the plant as a good candidate for further investigations

    Evaluation of anti-inflammatory effect of Salvadora persica in IBD-induced rat

    No full text
    Background and objectives: Inflammatory bowel diseases (IBD) are among the most prevalent diseases in developed countries. In general, IL-6 and TNF-α are considered as the main causes of tissue damage in the intestine. Salvadora persica is a domestic and abundant plant growing in some central and southern areas of Iran. The main objective of the current study was to evaluate the potential anti-inflammatory effect of the hydro-alcoholic extract of Salvadora persica in a rat model of IBD. Methods: Acute colitis was induced by intra-rectal administration of 100 mg/kg TNBS dissolved in a total volume of 0.25 mL of 50% ethanol. Twenty-four h after colitis induction, saline, S. persica extracts (25, 50 and 100 mg/kg) and sulfasalazine (100 mg/kg) were orally administered to the corresponding groups of animals. The dose administration was repeated daily for seven consecutive days. Aftewards, body weight changes, macroscopic and microscopic lesions were assessed by dissecting 8 cm of the distal colons of the animals. TNF-α and IL-6 mRNA expression were also evaluated by real-time PCR. Results: The obtained results showed that sulfasalazine and S. persica extracts were significantly able to reduce the body weight loss, macroscopic and microscopic lesions compared to the untreated control. Additionally, they were able to decrease the expression of TNF-α mRNA in the colon tissue. Conclusion: The findings of this study indicated that Salvadora persica extract had an acceptable anti-inflammatory effect on the induced colitis in rat, and one of its notable mechanisms could be through TNF-α pathway

    Anticancer Activity of Ipomoea purpurea Leaves Extracts in Monolayer and Three-Dimensional Cell Culture

    No full text
    Cancer is a leading cause of death and a vital health care challenge in the world. Hence, this work was conducted to determine the in vitro anticancer property and also the molecular mechanism of aqueous and organic extracts of Ipomoea purpurea leaves in three human cancer cell lines, including A-549 (human lung cancer), HepG-2 (human liver cancer), MDA-MB-231 (human breast cancer), and MCF-10A (breast normal cell line). In vitro cytotoxic potential of organic extracts, such as hexane, chloroform, ethyl-acetate, methanol, and aqueous extract was examined using a standard (3-(4,5-dimethylthiazole)-2,5-diphenyltetrazolium bromide) MTT method in both monolayer two-dimensional (2D) and spheroids multicellular three-dimensional (3D) cultures. The MTT assay data showed that methanol and chloroform extracts of I. purpurea leaves had the antiproliferative effect on lung and breast cancer cells with IC50 of 53.62 ± 0.07 and 124.5 ± 0.01 µg/mL, respectively. The results of further examinations, such as dual acridine orange/ethidium bromide, Annexin V-FITC/PI, and caspase-3 colorimetric assay, confirmed that methanol and chloroform extracts of I. purpurea as the most potent cytotoxic extracts might contain a variety of phytochemicals, promoting apoptosis in lung and breast cancer cells. The present research findings suggested that methanolic extract of I. purpurea leaves induced S-phase cell cycle arrest and intrinsic pathway of apoptosis in A-549 lung cancer cells. The study further showed that I. purpurea could be a helpful candidate for cancer treatment

    Malaria Status in Economic Cooperation Countries; Achievement and Gaps Toward United Nations Millennium Development Goals

    No full text
    Background: Evaluating the malaria status of the Economic Cooperation Organization (ECO) member countries relation to goal 6 of 3rd Millennium Development Goals (MDGs) which includes have halted by 2015 and begun to reverse the incidence of malaria.Methods: By 2009, we reviewed the MDGs reports, extracted the data from surveillance system, published, and unpublished data. The main stakeholders, from both governmental and international organizations in the country have been visited and interviewed by the research team as part of the data validation process.Results: The malaria incidence is very heterogeneous among ECO countries, which differ less than 200 cases in total country in Kazakhstan, Kyrgyzstan, Turkey, Turkmenistan, Uzbekistan, and Azerbaijan to 82,564 cases (2,428/100,000) in Afghanistan and 59,284 cases (881/100,000) in Pakistan and about 18/100,000 in Iran in 2008. Malaria has been a major public health problem in Pakistan and Afghanistan and will continue to pose serious threat to millions of people due to poor environmental and socioeconomic conditions conducive to the spread of disease. The main malaria endemic areas of Iran are in southeastern part of the country; consist of less developed provinces that are bordered in the east by Afghanistan and Pakistan. There are little valid information about proportion of population in malaria-risk areas using effective malaria prevention and treatment measures indicators.Conclusion: All ECO countries could achieve MDGs malaria indicators by 2015 except Pakistan and Afghanistan, unless preparing urgent intervention programs to fulfill the goals

    Antimicrobial effect of cinnamon (Cinnamomum verum J. Presl) bark essential oil in cream-filled cakes and pastries

    No full text
    Background and objectives: Food poisoning has been always a major concern in health system of every community and cream-filled products are one of the most widespread food poisoning causes in humans. In present study, we examined the preservative effect of the cinnamon oil in cream-filled cakes. Methods: Antimicrobial activity of Cinnamomum verum J. Presl (Cinnamon) bark essential oil was examined against five food-borne pathogens (Staphylococcus aureus, Escherichia coli, Candida albicans, Bacillus cereus and Salmonella typhimurium) to investigate its potential for use as a natural preservative in cream-filled baked goods. Chemical constituents of the oil were determined by gas chromatography/mass spectrometry. For evaluation of preservative sufficiency of the oil, pathogens were added to cream-filled cakes manually and 1 μL/mL of the essential oil was added to all samples except the blank.  Results: Chemical constituents of the oil were determined by gas chromatography/mass spectrometry and twenty five components were identified where cinnamaldehyde (79.73%), linalool (4.08%), cinnamaldehyde para-methoxy (2.66%), eugenol (2.37%) and trans-caryophyllene (2.05%) were the major constituents. Cinnamon essential oil showed strong antimicrobial activity against selected pathogens in vitro and the minimum inhibitory concentration values against all tested microorganisms were determined as 0.5 μL/disc except for S. aureus for which, the oil was not effective in tested concentrations. After baking, no observable microorganism was observed in all susceptible microorganisms count in 72h stored samples.  Conclusion: It was concluded that by analysing the sensory quality of the preserved food, cinnamon oil may be considered as a natural preservative in food industry, especially for cream-filled cakes and pastries
    corecore