Search results for: coke formation

Authors: O.M. Agbogidi, I.M. Onochie

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An investigation was carried out on trace metal concentration of soils contaminated with carbide in Abraka, Delta State, Nigeria in 2014 with a view to providing baseline formation on their status relative to the control plants and to the tolerable limits recommended by World standard bodies including WHO and FAO. The metals were analyzed using the Atomic Absorption Spectrophotometer which showed an elevated level when compared with the control plots. High level of metals including Fe, Pb, Zn, Cu, Cd, Ni, Cr and arsenic were recorded and these values were significantly different (P<0.05) from values obtained from the control plots. These results are indicative of the fact that carbide polluted soil had higher level of trace metals and because these metals are non-biodegradable elements in the ecosystem, a rise to their lethal levels in food chains is envisaged due to the interdependency of plants and animals stemming from soil-water organisms interrelationship.

Keywords: bio-concentration, carbide contaminated soils, heavy metals, trace metals

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Authors: Federico Cevoli

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Purinergic P2X7 receptors (P2X7R) are ligand-gated non-selective cation channels involved in several physiological and pathological processes. They are particularly promising pharmacological targets as they are present in an increasing number of different cells types. P2X7R activation is triggered following elevated concentrations of extracellular ATP, similarly to those observed in tissues injury, chronic inflammation and T-cell activation, as well as in the scrambling of phospholipids leading to membrane blebbing and apoptosis. Another hallmark of P2X7 is cell permeabilization, commonly known as “macropore” formation allowing the passage of nanometer-sized molecules up to 900Da. Recently, full-length P2X7 Cryo-EM structures revealed unique functional sites, including two cytoplasmic domains - the cytoplasmic "anchor" and "ballast". To date, the molecular units/complex by which P2X7R exerts its pathophysiological functions are unknown. Using custom-made cell-penetrating HIV-1 TAT peptides, we show for the first-time potential implications of P2X7 cytoplasmic anchor in the regulation of caspase3/7 activation as well as TNFα regulation.

Keywords: P2X7R, immunology, TAT-peptide, cell death

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Authors: Saurabh Sharma

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Introduction: The case study deals with the ground stabilisation of Nabi Karim Metro Station in Delhi, India, wherein an extremely complex geology was encountered while excavating the tunnelling shaft for launching Tunnel Boring Machine. The borelog investigation and the Seismic Refraction Technique (SRT) indicated towards the presence of an extremely hard rocky mass from a depth of 3-4 m itself, and accordingly, the Geotechnical Interpretation Report (GIR) concluded the presence of Grade-IV rock from 3m onwards and presence of Grade-III and better rock from 5-6m onwards. Accordingly, it was planned to retain the ground by providing secant piles all around the launching shaft and then excavating the shaft vertically after leaving a berm of 1.5m to prevent secant piles from getting exposed. To retain the side slopes, rock bolting with shotcreting and wire meshing were proposed, which is a normal practice in such strata. However, with the increase in depth of excavation, the rock quality kept on decreasing at an unexpected and surprising pace, with the Grade-III rock mass at 5-6 m converting to conglomerate formation at the depth of 15m. This worsening of geology from high grade rock to slushy conglomerate formation can never be predicted and came as a surprise to even the best geotechnical engineers. Since the excavation had already been cut down vertically to manage the shaft size, the execution was continued with enhanced cautions to stabilise the side slopes. But, when the shaft work was about to finish, a collapse was encountered on one side of the excavation shaft. This collapse was unexpected and surprising since all measures to stabilise the side slopes had been taken after face mapping, and the grid size, diameter, and depth of the rockbolts had already been readjusted to accommodate rock fractures. The above scenario was baffling even to the best geologists and geotechnical engineers, and it was decided that any further slope stabilisation scheme shall have to be designed in such a way to ensure safe completion of works. Accordingly, following revisions to excavation scheme were made: The excavation would be carried while maintaining a slope based on type of soil/rock. The rock bolt type was changed from SN rockbolts to Self Drilling type anchor. The grid size of the bolts changed on real time assessment. the excavation carried out by implementing a ‘Bench Release Approach’. Aggressive Real Time Instrumentation Scheme. Discussion: The above case Study again asserts vitality of correct interpretation of the geological strata and the need of real time revisions of the construction schemes based on the actual site data. The excavation is successfully being done with the above revised scheme, and further details of the Revised Slope Stabilisation Scheme, Instrumentation Schemes, Monitoring results, along with the actual site photographs, shall form the part of the final Paper.

Keywords: unconfined compressive strength (ucs), rock mass rating (rmr), rock bolts, self drilling anchors, face mapping of rock, secant pile, shotcrete

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Authors: Muzammil Dar

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The confluence of trans-national interests and divergent approaches followed by multiple actors has surrounded the Indo-Pacific region with myriad of strategic complexes- Geo-Political, Geo-economic, and security. This paper has thus made a humble attempt to understand the Indo-Pacific strategic predicament from Asia-Pacific perspective. The portmanteau of Indo-Pacific strategic gamble has multiple actors from global powers to regional actors. On the indo-pacific waters, not only flow trade relations, but the tides of conflicts and controversies are striking these actors against each other. The alliance formation and infrastructure building has built-in threat perceptions from rivals vice-versa. The assertiveness of China as a reality and India’s ideological doctrine of peace and friendship, as well as American rebalancing against China, could be seen as clear and bright on the Indo-Pacific strategic portmanteau. ASEAN and Japan, too, have oscillating posturing in the strategic dilemma. The aim and objective of the paper are to sketch out the prospectus and prejudices of Indo-pacific strategic complex.

Keywords: Indo Pacific, Asia Pacific, security and growth for all in the region, SAGAR, ASEAN China

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Authors: Mohammadreza Nezamirad, Sepideh Amirahmadian, Nasim Sabetpour, Azadeh Yazdi, Amirmasoud Hamedi

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Cavitation inside the diesel injector nozzle is investigated numerically in this study. Reynolds Stress Navier Stokes set of equations (RANS) are utilized to investigate flow behavior inside the nozzle numerically. Moreover, K-ε turbulent model is found to be a better approach comparing to K-ω turbulent model. Winklhofer rectangular shape nozzle is also simulated in order to verify the current numerical scheme, and with, mass flow rate approach, the current solution is verified. Afterward, a six-hole real-size nozzle was simulated, and it was found that among different fuels used in this study with the same condition, diesel fuel provides the largest length of cavitation. Also, it was found that at the same boundary condition, RME fuel leads to the highest value of discharge coefficient and mass flow rate.

Keywords: cavitation, diesel fuel, CFD, real size nozzle, discharge coefficient

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Authors: Yi-De Liu

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The aim of this paper is to discuss how the construct of networking and social capital can be used to understand the effect events can have on the cultural sector. Based on case study, this research sought the views of those working in the cultural sector on Liverpool’s year as the European Capital of Culture (ECOC). Methodologically, this study involves literature review to prompt theoretical sensitivity, the collection of primary data via online survey (n= 42) and follow-up telephone interviews (n= 8) to explore the emerging findings in more detail. The findings point to a number of ways in which the ECOC constitutes a boost for networking and its effects on city’s cultural sector, including organisational learning, aspiration and leadership. The contributions of this study are two-fold: (1) Evaluating the long-term effects on network formation in the cultural sector following major event; (2) conceptualising the impact assessment of organisational social capital for future ECOC or similar events.

Keywords: network, social capital, cultural impact, european capital of culture

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Authors: Talal Al-Bazali

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Air drilling has recently received increasing acceptance by the oil and gas industry due to its unique advantages. The main advantages of air drilling include the higher rate of penetration, less formation damage, lower risk of loss of circulation. However, these advantages cannot be fully realized if thermal effects in air drilling are not well understood and minimized. Due to its high frictional coefficient, low heat conductivity, and high compressibility, air can impact the temperature distribution of bit and thus affect its bit performances. Based on energy and mass balances, a transient thermal model that predicts bit temperature is presented along with numerical solutions in this paper. In addition, several important parameters that influence bit temperature distribution are analyzed. Simulation results show that the bit temperature increases with increasing weight on bit and rotary speed but decreases as the standpipe pressure and flow rate increase. These results can be used to optimize drilling operations and flow parameters for an improved bit performance as shown in this paper.

Keywords: air drilling, rate of penetration, temperature, rotary speed

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Authors: Evgeniya Popova, Vladimir Lesnikov, Nikolay Popov

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High yield complex coatings have been designed for thermally stressed cooled HP turbine blades from single crystal alloys ZHS32-VI-VI and ZHS36 with crystallographic orientation [001]. These coatings provide long-term protection of single crystal blades during operation. The three-layer coatings were prepared as follows: the diffusion barrier layer formation on the alloy surface, the subsequent deposition of the condensed bilayer coatings consisting of an inner layer based on Ni-Cr-Al-Y systems and an outer layer based on the alloyed β-phase. The structure, phase composition of complex coatings and reaction zone interaction with the single-crystal alloys ZHS32-VI and ZHS36-VI were investigated using scanning electron microscope (SEM). The effect of complex protective coatings on the properties of heat-resistant nickel alloys was studied.

Keywords: single crystal nickel alloys, complex heat-resistant coatings, structure, phase composition, properties

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Authors: H. Khaled, F. Chaabani, F. Boulvain

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This paper focuses on the studied of Aptian series that crops out at the Jebel Serdj in the north central Tunisia. The study series is about 590 meters thick and it is consisting of limestones, marly limestones associated with some levels of siltstones and marls. Two sections are studied in detail regarding lithology, microfacies, magnetic susceptibility and mineralogical composition to provide new insights into the paleoenvironmental evolution and paleoclimatological implications during this period. The following facies associations representing different ramp palaeoenvironments have been identified: mudstone–wackestone outer ramp facies; skeletal grainstone- packstone mid-ramp facies, packstone-grainstone inner-ramp facies which include a variety of organisms such as rudists and ooids and mudstone–wackestone coastal facies rich with miliolidea and orbitolines. The magnetic susceptibility (Xᵢₙ) of all samples was compared with the lithological and microfacies variation. We show that high values of magnetic susceptibility are correlated with the distal facies.

Keywords: Aptian, Serdj Formation, geochemical, mineralogy

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Authors: Samar Aoujia, Théo Guérineaub, Rayan Zaitera, Evelyne Fargina, Younès Messaddeqb, Thierry Cardinala

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Two barium gallo-germanate glass series were elaborated to investigate the effect of the yttrium introduction on the glass physicochemical properties and crystallization behavior. One to twenty mol% of YO3/2 were either added into the glass matrix or substituted for gallium oxide. The glass structure was studied by Raman spectroscopy, and the thermal, optical, thermo-mechanical and physical properties are examined. The introduction of yttrium ions in both glass series increases the glass transition temperature, crystallization temperature, softening temperature, coefficient of linear thermal expansion and density. Through differential scanning calorimetry and X-ray diffraction analyses, it was found that competition occurs between the gallo-germanate zeolite-type phase and the yttrium-containing phase. From 13 mol% of YO3/2, the yttrium introduction impedes the formation of surface crystallization in these glasses.

Keywords: photonic, heavy-metal oxide, glass, crystallization

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Authors: Parsa Sheikhzadeh

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Polar bodies are cells that form by oogenesis in meiosis which differentiate and develop from oocytes. Although in many animals, these cells often die following meiotic maturation of the oocyte. Oocyte activation is during mammalian fertilization, sperm is fused with the oocyte's membrane, triggering the resumption of meiosis from the metaphase II arrest, the extrusion of the second polar body, and the exocytosis of cortical granules. The origin recognition complex proteins 4 (ORC4) forms a cage around the set of chromosomes that will be extruded during polar body formation before it binds to the chromatin shortly before zygotic DNA replication. One unique feature of the female gamete is that the polar bodies can provide beneficial information about the genetic background of the oocyte without potentially destroying it. Testing at the polar body (PB) stage was the least accurate, mainly due to the high incidence of post-zygotic events. On the other hand, the results from PB1-MII oocyte pair validated that PB1 contains nearly the same methylome (average Pearson correlation is 0.92) with sibling MII oocyte. In this article, we comprehensively examine the role of polar bodies in female human gametes.

Keywords: polar bodies, ORC4, oocyte, genetic, methylome, gamete, female

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Authors: Ken Ninez Nurpramesti Prinindya, Yuli Setiyorini

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Crown enclosure high temperature flares damaged and reduced dimensions crown. Generally crown on EHTF could have a life time up to twenty years. Therefore, this study aims to increase the value of thermal resistance with the effect post treatment on NiCr coated arc spray method. The variation of post treatment temperature, was at 650°C, 750°C, and 850°C. Morphology on the surface and the adhesion strength was analyzed by SEM-EDX, Surface Roughness and Pull - off test. XRD testing was conducted to determine the contained in NiCr coated. Thermal stability of NiCr coated was tested by DSC-TGA. The most optimal results was owned by NiCr coating with post treated at 850°C. It has good thermal stability until 1000°C because of Cr2O3 formation in coated specimen. The higher temperature of post treatment coating was showed better result on porosity and roughness surface value.

Keywords: Arc spray process, NiCr wire, post-treatment coating, high temperature-corrosion resistance

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Authors: Amir Doustgani

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Melt electrospinning is a safe and simple technique for the production of micro and nanofibers which can be an alternative to conventional solvent electrospinning. The effects of various melt-electrospinning parameters, including molecular weight, electric field strength, flow rate and temperature on the morphology and fiber diameter of polylactic acid were studied. It was shown that molecular weight was the predominant factor in determining the obtainable fiber diameter of the collected fibers. An orthogonal design was used to examine process parameters. Results showed that molecular weight is the most effective parameter on the average fiber diameter of melt electrospun PLA nanofibers and the flow rate has the less important impact. Mean fiber diameter increased by increasing MW and flow rate, but decreased by increasing electric field strength and temperature. MFD of optimized fibers was below 100 nm and the result of software was in good agreement with the experimental condition.

Keywords: fiber formation, processing, spinning, melt blowing

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Authors: Tan Yong Sheng Edgar, Yeong Wai Yee

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Age-related macular degeneration (AMD) is one of the leading cause of blindness. It can cause severe visual loss due to damaged retinal pigment epithelium (RPE). RPE is an important component of the retinal tissue. It functions as a transducing boundary for visual perception making it an essential factor for sight. The RPE also functions as a metabolically complex and functional cell layer that is responsible for the local homeostasis and maintenance of the extra photoreceptor environment. Thus one of the suggested method of treating such diseases would be regenerating these RPE cells. As such, we intend to grow these cells using a synthetic scaffold to provide a stable environment that reduces the batch effects found in natural scaffolds. Stiffness of the scaffold will also be investigated to determine the optimal Young’s modulus for cultivating these cells. The cells will be generated into a monolayer cell sheet and their functions such as formation of tight junctions and gene expression patterns will be assessed to evaluate the cell sheet quality compared to a native RPE tissue.

Keywords: RPE, scaffold, characterization, biomaterials, colloids and nanomedicine

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Authors: Durata Haciu, Ozgur Birer

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Zinc acetate solution is sonicated at high power in water and in ethanol in the absence and presence of various peroxides. In the absence of peroxides, the products are zinc oxide and layered hydroxy zinc acetate in water and in ethanol, respectively. Layered basic zinc acetate are prepared for the first time using sonochemical methods. The addition of peroxides alters the reaction mechanisms. In water, insoluble peroxides produce zinc oxides while the water soluble peroxide, i.e.hydrogen peroxide, completely destroyed the structure and casted a doubt on the accepted peroxide initiated mechanism of reactions. In ethanol,peroxide addition caused the reaction mechanism to change and some oxide formation is observed. The reaction mechanism is sensitive to water/ethanol amounts as well as the peroxide to zinc ion mole ratio.Thin zinc oxide wafers (ca. 30 nm) with band gaps of 3.24 eV were obtained.

Keywords: ultrasound, zinc oxide, hydroxy zinc acetate, fenton, peroxide initiation

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Authors: Theo Neethling

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The United States Africa Command (AFRICOM) was established in 2007 as a military and diplomatic entity and is intended to assist African states and military actors to address their security needs. At the same time, AFRICOM is clearly an extension of US strategic interests on the African continent. The challenge for the US Department of Defence is to project AFRICOM as a cooperative and willing partner. This implies a partner that offers needed services and resources, and supports African security and military priorities with no presumption of having a privileged role in defining the African future. However, one of AFRICOM’s main challenges relates to the point that it has not been able to secure a firm partnership with South Africa as a key player on the continent: South Africa has continuously taken a lukewarm, if not cold, approach towards AFRICOM since its formation. The main aim of this article is to examine and discuss South Africa’s political-military relations with AFRICOM and to assess the underlying reasons currently inhibiting AFRICOM from achieving a fully productive relationship with the South African government.

Keywords: AFRICOM, South African foreign policy, US interests, defence capabilities in Africa, US-Africa relations

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Authors: Hadjer Didouh, Mohammed Hadj Meliani, Izzaddine Sameut Bouhaik

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This study employs a multidisciplinary approach to investigate the intricate processes governing biofilm-surface interactions. Results indicate that surface properties significantly influence initial microbial attachment, with materials characterized by increased roughness and hydrophobicity promoting enhanced biofilm adhesion. Moreover, the chemical composition of materials plays a crucial role in impacting the development of biofilms. Environmental factors, such as temperature fluctuations and nutrient availability, were identified as key determinants affecting biofilm formation dynamics. Advanced imaging techniques revealed complex three-dimensional biofilm structures, emphasizing microbial communication and cooperation within these networks. These findings offer practical implications for industries operating in crude oil environments, guiding the selection and design of materials to mitigate biofilm-related challenges and enhance operational efficiency in such settings.

Keywords: biofilm adhesion, surface properties, crude oil environments, microbial interactions, multidisciplinary investigation

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Authors: Josephine Shamash, Stuart Smith

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We examine reasons for introducing definitions in teaching mathematics in a number of different cases. We try to determine if, where, and when to provide a definition, and which definition to choose. We characterize different types of definitions and the different purposes we may have for formulating them, and detail examples of each type. Giving a definition at a certain stage can sometimes be detrimental to the development of the concept image. In such a case, it is advisable to delay the precise definition to a later stage. We describe two models, the 'successive approximation model', and the 'model of the extending definition' that fit such situations. Detailed examples that fit the different models are given based on material taken from a number of textbooks, and analysis of the way the concept is introduced, and where and how its definition is given. Our conclusions, based on this analysis, is that some of the definitions given may cause discontinuities in the learning sequence and constitute obstacles and unnecessary cognitive conflicts in the formation of the concept definition. However, in other cases, the discontinuity in passing from definition to definition actually serves a didactic purpose, is unavoidable for the mathematical evolution of the concept image, and is essential for students to deepen their understanding.

Keywords: concept image, mathematical definitions, mathematics education, mathematics teaching

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Authors: R. Benakcha, M. Omari

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Powders of La1-xMgxAlO3 (0 ≤ x ≤ 5) oxides, with large surface areas were synthesized by sol-gel process, utilizing citric acid. Heating of a mixed solution of CA, EtOH, and nitrates of lanthanum, aluminium and magnesium at 70°C gave transparent gel without any precipitation. The formation of pure perovskite La1-xMgxAlO3, occurred when the precursor was heat-treated at 800°C for 6 h. No X-ray diffraction evidence for the presence of crystalline impurities was obtained. The La1-xMgxAlO3 powders prepared by the sol-gel method have a considerably large surface area in the range of 12.9–20 m^2.g^-1 when compared with 0.3 m^2.g^-1 for the conventional solid-state reaction of LaAlO3. The structural characteristics were examined by means of conventional techniques namely X-ray diffraction, infrared spectroscopy, thermogravimetry and differential thermal (TG-DTA) and specific surface SBET. Pore diameters and crystallite sizes are in the 8.8-11.28 nm and 25.4-30.5 nm ranges, respectively. The sol-gel method is a simple technique that has several advantages. In addition to that of not requiring high temperatures, it has the potential to synthesize many kinds of mixed oxides and obtain other materials homogeneous and large purities. It also allows formatting a variety of materials: very fine powders, fibers and films.

Keywords: aluminate, lanthan, perovskite, sol-gel

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Authors: Onan Kilicaslan, Anil Kabaklarli, Levent Subasi, Erdem Bektas, Rifat Yilmaz

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The Aluminum-Copper casting alloys are well known for their high mechanical strength, especially when compared to more commonly used Aluminum-Silicon alloys. A201 is one of the best in terms of strength vs. weight ratio among other aluminum alloys, which makes it suitable for premium quality casting applications in aerospace and automotive industries. It is reported that A201 has low castability, but it is easy to machine. However, there is a need to specifically determine the process window for feasible machining. This research investigates the machinability of A201 alloy after T7 heat treatment in terms of chip/burr formation, surface roughness, hardness, and microstructure. The samples are cast with low-pressure sand casting method and milling experiments are performed with uncoated carbide tools using different cutting speeds and feeds. Statistical analysis is used to correlate the machining parameters to surface integrity. It is found that there is a strong dependence of the cutting conditions on machinability and a process window is determined.

Keywords: A201-T7, machinability, milling, surface integrity

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Authors: Christabel Ihedike, John Mooney, Monica Price

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Summary: This study aims to critically evaluate effect of photochemical smog on respiratory health in Nigeria. Cohort of chronic obstructive pulmonary disease (COPD) patients was recruited from two large hospitals in Abuja Nigeria. Respiratory health questionnaires, daily diaries, dyspnoea scale and lung function measurement were used to obtain health data and investigate the relationship with air quality data (principally ozone, NOx and particulate pollution). Concentrations of air pollutants were higher than WHO and Nigerian air quality standard. The result suggests a correlation between measured air quality and exacerbation of respiratory illness. Introduction: Photochemical smog is a significant health challenge in most cities and its effect on respiratory health is well acknowledged. This type of pollution is most harmful to the elderly, children and those with underlying respiratory disease. This study aims to investigate impact of increasing temperature and photo-chemically generated secondary air pollutants on respiratory health in Abuja Nigeria. Method and Result: Health data was collected using spirometry to measure lung function on routine attendance at the clinic, daily diaries kept by patients and information obtained using respiratory questionnaire. Questionnaire responses (obtained using an adapted and internally validated version of St George’s Hospital Respiratory Questionnaire), shows that ‘time of wheeze’ showed an association with participants activities: 30% had worse wheeze in the morning: 10% cannot shop, 15% take long-time to get washed, 25% walk slower, 15% if hurry have to stop and 5% cannot take-bath. There was also a decrease in Forced expiratory volume in the first second and Forced Vital Capacity, and daily change in the afternoon–morning may be associated with the concentration level of pollutants. Also, dyspnoea symptoms recorded that 60% of patients were on grade 3, 25% grade 2 and 15% grade 1. Daily frequency of the number of patients in the cohort that cough /brought sputum is 78%. Air pollution in the city is higher than Nigerian and WHO standards with NOx and PM10 concentrations of 693.59ug/m-3 and 748ugm-3 being measured respectively. The result shows that air pollution may increase occurrence and exacerbation of respiratory disease. Conclusion: High temperature and local climatic conditions in urban Nigeria encourages formation of Ozone, the major constituent of photochemical smog, resulting also in the formation of secondary air pollutants associated with health challenges. In this study we confirm the likely potency of the pattern of secondary air pollution in exacerbating COPD symptoms in vulnerable patient group in urban Nigeria. There is need for better regulation and measures to reduce ozone, particularly when local climatic conditions favour development of photochemical smog in such settings. Climate change and likely increasing temperatures add impetus and urgency for better air quality standards and measures (traffic-restrictions and emissions standards) in developing world settings such as Nigeria.

Keywords: Abuja-Nigeria, effect, photochemical smog, respiratory health

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Authors: Md Fazle Alam, Amaj Ahmed Laskar, Hina Younus

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Melamine toxicity which causes renal failure and death of humans and animals have recently attracted worldwide attention. Developing an easy, fast and sensitive method for the routine melamine detection is the need of the hour. Herein, we have developed a rapid, sensitive, one step and selective colorimetric method for the detection of melamine in milk samples based upon in-situ formation of silver nanoparticles (AgNPs) via tannic acid at room temperature. These AgNPs thus formed were characterized by UV-VIS spectrophotometer, transmission electron microscope (TEM), zetasizer and dynamic light scattering (DLS). Under optimal conditions, melamine could be selectively detected within the concentration range of 0.05-1.4 µM with a limit of detection (LOD) of 10.1 nM, which is lower than the strictest melamine safety requirement of 1 ppm. This assay does not utilize organic cosolvents, enzymatic reactions, light sensitive dye molecules and sophisticated instrumentation, thereby overcoming some of the limitations of conventional methods.

Keywords: milk adulteration, melamine, silver nanoparticles, tannic acid

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Authors: Nhat-To Huynh, Chen-Fu Chien

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Textile batch dyeing scheduling problem is complicated which includes batch formation, batch assignment on machines, batch sequencing with sequence-dependent setup time. Most manufacturers schedule their orders manually that are time consuming and inefficient. More power methods are needed to improve the solution. Motivated by the real needs, this study aims to propose approaches in which genetic algorithm is developed with multi-subpopulation and hybridised with estimation of distribution algorithm to solve the constructed problem for minimising the makespan. A heuristic algorithm is designed and embedded into the proposed algorithms to improve the ability to get out of the local optima. In addition, an empirical study is conducted in a textile company in Taiwan to validate the proposed approaches. The results have showed that proposed approaches are more efficient than simulated annealing algorithm.

Keywords: estimation of distribution algorithm, genetic algorithm, multi-subpopulation, scheduling, textile dyeing

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Authors: Aneesa Shafi

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Reproduction is a complex term in a setting where it is continuously being shaped by epistemological shifts in knowledge. It denotes not just fertility, birth and childcare related practices but also the ideas that shape those practices. These ideas and practices figure into understandings of social and cultural renewal. Patriarchy continues to be a dominating force in the formation of these ideas and practices. Contemporary times are characterized by the resurgence of the whims of patriarchal politics in delineating the margins of women’s health care. This has further emboldened the struggle for reproductive rights on the global stage. The paper examines the subordination of the right to bodily autonomy of women within the ambit of their reproductive rights. Reproductive rights are recognized human rights and women’s rights. Why these rights of women face stiff opposition is established, as is the structure that creates hurdles to their enjoyment. The negotiation of this structure in the everyday life through women’s agency is also established. The reproductive sphere includes not just the process of reproduction but also social reproduction- domestic work, spheres of production and reproduction, population and birth (control) issues.

Keywords: patriarchy, women, reproduction, gender

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Authors: Ersin Bozkurt

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The aim of the study is to develop materials for understanding image formations through virtual objects in geometric optics. The images in physics course books are formed by using real objects. This results in mistakes in the features of images because of generalizations which leads to conceptual misunderstandings in learning. In this study it was intended to identify pre-service physics teachers misunderstandings arising from false generalizations. Focused group interview was used as a qualitative method. The findings of the study show that students have several misconceptions such as "the image in a plain mirror is always virtual". However a real image can be formed in a plain mirror. To explain a virtual object's image formation in a more understandable way an overhead projector and episcope and their design was illustrated. The illustrations are original and several computer simulations will be suggested.

Keywords: computer simulations, geometric optics, physics education, students' misconceptions in physics

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Authors: Huiwu Yu, Xiangyou Li, Xiaoyan Zeng

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Porous spheres have been widely used in many fields due to their attractive features. In this work, an approach for fabricating porous spheres of nanoparticles was presented, in which the nanoparticles were welded together to form micro spheres by simply irradiating the nanoparticles in liquid medium by a picosecond laser. As an example, anatase titanium dioxide was chosen as a typical material on account of its metastability. The structure and morphologies of the products were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman, and high-resolution transmission electron microscopy (HRTEM), respectively. The results showed that, anatase titanium dioxide micro spheres (2-10 μm) with macroporous (10-100 nm) were prepared from nano-anatase titanium dioxide nanoparticles (10-100 nm). The formation process of polycrystalline anatase titanium dioxide microspheres was investigated with different liquid mediums and the input laser fluences. Thus, this facile laser irradiation approach might provide a way for the fabrication of porous microspheres without phase-transition.

Keywords: titanium dioxide, porous microspheres, picosecond laser, nano-welding

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Authors: Galina Mamardashvili, Nugzar Mamardashvili, Win Dehaen

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The processes of complexation of the Zn-tetraarylporphyrins with eight 4-(4-(3,6-bis(t-butyl)carbazol-9-yl-phenyl)-1,2,3-triazole (ZnP1) and eight 4-(4-(3,6-di-tert-butyl-9-H-carbazol-9-yl)phenoxy)methyl)-2,4,6-trimethylphenyl (ZnP2)with the 1,10-diaza-4,7,13,18tetraoxabicyclo[8.5.5]eicosane (L1),1,10-diaza-4,7,13,16,21,24-hexaoxabicyclo[8.8.8]hexacosane (L2)and 1,10-diaza-5,6,14,15-dibenzo-4,7,13,16,21,24 hexaoxabicyclo[8.8.8] hexacosane (L3) were investigated by the method of spectrophotometric titration and ¹H NMR-spectroscopy. We determined the structures of the host-guest complexes, and their stability constants in toluene were calculated. It was found out that the ZnP1 interacts with the guest molecules L1, L2 with the formation of stable "nest" type complexes and does not form similar complexes with the L3 (presumably due to the fact that the L3 does not match the size of the porphyrin ZnP(1) cavity). On the other hand, the porphyrin ZnP2 binds all of the ligands L1-L3, however complexes thus formed are less stable than complexes ZnP1-L1, ZnP1-L2. In the report, we will also discuss the influence of the alkali cations additives on the stability of the complexes between the porphyrin ZnP1, ZnP2 hosts and guest molecules of the ligands L1-L3.

Keywords: porphyrin, cryptand, cation, complex guest-host

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Authors: K. Mehmood, Muhammad Asif Rafiq, A. Nasir Khan, M. Mudassar Rauf

Abstract:

Air plasma spraying system was utilized to deposit Ni3Al coatings on AISI 321 steel samples. After thermal spraying, the nickel aluminide intermetallic coatings were isothermal heat treated at various temperatures. In this regard, temperatures from 500 °C to 800 °C with 100 °C increments were selected. The coatings were soaked for 10, 30, 60 and 100 hours at the mentioned temperatures. These coatings were then tested by a pin on disk method. It was observed that the coatings exposed at comparatively higher temperature experienced lower wear rate. The decrease in wear rate is due to the formation of NiO phase. Further, the as sprayed and heat treated coatings were characterized by other tools such as Microhardness testing, optical and scanning electron microscopy (SEM) and X-Ray diffraction analysis. After isothermal heat treatment, NiO was observed the main phase by X-Ray diffraction technique. Moreover, the surface hardness was also determined higher than cross sectional hardness.

Keywords: air plasma spraying, Ni -20Al, tribometer, intermetallic coating, nickel aluminide

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Authors: Azadeh Malekan, Shahin Rouhani

Abstract:

Superlubricity is a phenomenon where two surfaces in contact show negligible friction;this may be because the asperities of the two surfaces do not interlock. Two rough surfaces, when pressed against each other, can get into a formation where the summits of asperities of one surface lock into the valleys of the other surface. The amount of interlock depends on the geometry of the two surfaces. We suggest the friction force may then be proportional to the amount of interlock; this explains Superlubricity as the situation where there is little interlock. Then the friction force will be directly proportional to the normal force as it is related to the work necessary to lift the upper surface in order to clear the interlock. To investigate this model, we simulate the contact of two surfaces. In order to validate our model, we first investigate Amontons‘ law. Assuming that asperities retain deformations in the time scale while the top asperity moves across the lattice spacing Amonton’s law is observed. Structural superlubricity is examined by the hypothesis that surfaces are very rigid and there is no deformation in asperities. This may happen at small normal forces. When two identical surfaces come into contact, rotating the top surface we observe a peak in friction force near the angle of orientation where the two surfaces can interlock.

Keywords: friction, amonton`s law, superlubricity, contact model

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Authors: Gurleen Kaur

Abstract:

Being tall-short, fat-thin, black-white, etc. is an inevitable part of how people perceive you. This association of people with your external appearance carves out an identity for you. This paper will look at the reasons why people relate a person to a particular categorization on the basis of his/her physical appearance. The paper delves into reasons for this categorization into groups: Subconscious grouping, personal gain, ease of relating to the group, and social acceptance. Development of certain unique physical features also leads to a person relating himself to a collective identity. Thus, this paper will support the fact that physical appearance plays a crucial role in categorization of people into groups and hence forming a group identity for them. This paper is divided into three parts. The first part will discuss what physical appearance is and how is it linked to our daily lives. The second part will talk about why it works i.e. why this factor of external appearance is important in formation of identity. The last part will talk about the factors which lead to categorization of identity because of physical appearance.

Keywords: group identity, physical appearance, subconscious grouping, collective identity

Procedia PDF Downloads 419