Search results for: abstract differential equation

Authors: Mathew Saxon A, Aneeh Rajan, Sajeev P

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Many fluid flow applications employ different types of orifices to control the flow rate or to reduce the pressure. Discharge coefficients generally vary from 0.6 to 0.95 depending on the type of the orifice. The tabulated value of discharge coefficients of various types of orifices available can be used in most common applications. The upstream and downstream flow condition of an orifice is hardly considered while choosing the discharge coefficient of an orifice. But literature shows that the discharge coefficient can be affected by the presence of cross flow. Cross flow is defined as the condition wherein; a fluid is injected nearly perpendicular to a flowing fluid. Most researchers have worked on water being injected into a cross-flow of water. The present work deals with water to gas systems in which water is injected in a normal direction into a flowing stream of gas. The test article used in the current work is called thermal regulator, which is used in a liquid rocket engine to reduce the temperature of hot gas tapped from the gas generator by injecting water into the hot gas so that a cooler gas can be supplied to the turbine. In a thermal regulator, water is injected through an orifice in a normal direction into the hot gas stream. But the injection orifice had been calibrated under backpressure by maintaining a stagnant gas medium at the downstream. The motivation of the present study aroused due to the observation of a lower Cd of the orifice in flight compared to the calibrated Cd. A systematic experimental investigation is carried out in this paper to study the effect of cross-flow on the discharge coefficient of an orifice in water to a gas system. The study reveals that there is an appreciable reduction in the discharge coefficient with cross flow compared to that without cross flow. It is found that the discharge coefficient greatly depends on the ratio of momentum of water injected to the momentum of the gas cross flow. The effective discharge coefficient of different orifices was normalized using the discharge coefficient without cross-flow and it is observed that normalized curves of effective discharge coefficient of different orifices with momentum ratio collapsing into a single curve. Further, an equation is formulated using the test data to predict the effective discharge coefficient with cross flow using the calibrated Cd value without cross flow.

Keywords: cross flow, discharge coefficient, orifice, momentum ratio

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Authors: Mateusz Jeżowski, Jadwiga Fila, Paweł Poszytek

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This abstract summarizes the combined findings of several analyses carried out by the authors on the barriers to accessing international education mobility programs by people with fewer opportunities, especially those with a low level of cultural and social capital. Two flagship educational mobility initiatives of the European Union – the Erasmus+ Program and the European Solidarity Corps are aimed at equipping young people and participants of all ages with the qualifications and skills needed for their meaningful participation in a democratic society intercultural understanding and successful transition in the labour market. The heart of these programs is to come closer to people with fewer opportunities, including people with disabilities, migrants, as well as those facing socio-economic difficulties and displaying a low level of social and cultural capital. Still, people who participate in such initiatives usually demonstrate higher than average cultural and social capital, as understood by Pierre Bourdieu. First of all, the educational attainment of their parents is higher than the average. Secondly, they mostly live in large agglomerations, with good access to education and culture, which affects their foreign language skills as well as social and cultural competencies. Finally, participation in Erasmus+ Program or European Solidarity Corps is not their first educational mobility experience. It is therefore justified to state that their social and cultural capital, already high before taking part in Erasmus+ and European Solidarity Corps, becomes even higher once their international mobility activities have been over, at the expense of those people with fewer opportunities, who, in theory, could participate in those initiatives, nonetheless did not, for the following reasons: lack of sufficient information on such programs, financial obstacles or unappreciation of the value of international mobility. In their work, the authors will discuss what are, in the light of Bourdieu’s perception of social and cultural capital, the main obstacles for young people to participate in international mobility programs of the European Union and will offer comprehensive solutions rooted in their vast experience in management and implementation of Erasmus+ Program and European Solidarity Corps.

Keywords: cultural capital, educational mobility, Erasmus+, European solidarity corps, inclusion, social capital

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Authors: Pampita Chakraborty, Sukumar Mukherjee

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People with diabetes mellitus are more susceptible to developing infections, as high blood sugar levels can weaken the patient's immune system defences. People with diabetes are more adversely affected when they get an infection than someone without the disease, because you have weakened immune defences in diabetes. People who have minimally elevated blood sugar levels experience worse outcomes with infections. Diabetic patients in hospitals do not necessarily have a higher mortality rate due to infections, but they do face longer hospitalisation and recovery times. A study was done in a tertiary care unit in eastern India. Patients with type 2 diabetes mellitus infection were recruited in the study. A total of 520 cases of Type 2 Diabetes Mellitus were recorded out of which 200 infectious cases was included in the study. All subjects underwent detailed history & clinical examination. Microbiological samples were collected from respective site of the infection for microbial culture and antibiotic sensitivity test. Out of the 200 infectious cases urinary tract infection(UTI) was found in majority of the cases followed by diabetic foot ulcer (DFU), respiratory tract infection(RTI) and sepsis. It was observed that Escherichia coli was the most commonest pathogen isolated from UTI cases and Staphylococcus aureus was predominant in foot ulcers followed by other organisms. Klebsiella pneumonia was the major organism isolated from RTI and Enterobacter aerogenes was commonly observed in patients with sepsis. Isolated bacteria showed differential sensitivity pattern against commonly used antibiotics. The majority of the isolates were resistant to several antibiotics that are usually prescribed on an empirical basis. These observations are important, especially for patient management and the development of antibiotic treatment guidelines. It is recommended that diabetic patients receive pneumococcal and influenza vaccine annually to reduce morbidity and mortality. Appropriate usage of antibiotics based on local antibiogram pattern can certainly help the clinician in reducing the burden of infections.

Keywords: antimicrobial resistance, diabetic foot ulcer, respiratory tract infection, urinary tract infection

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Authors: Alex Fedoseyev

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This study explores Generalized Hydrodynamic Equations (GHE) for the simulation of turbulent flows. The GHE was derived from the Generalized Boltzmann Equation (GBE) by Alexeev (1994). GBE was obtained by first principles from the chain of Bogolubov kinetic equations and considered particles of finite dimensions, Alexeev (1994). The GHE has new terms, temporal and spatial fluctuations compared to the Navier-Stokes equations (NSE). These new terms have a timescale multiplier τ, and the GHE becomes the NSE when τ is zero. The nondimensional τ is a product of the Reynolds number and the squared length scale ratio, τ=Re*(l/L)², where l is the apparent Kolmogorov length scale, and L is a hydrodynamic length scale. The turbulence phenomenon is not well understood and is not described by NSE. An additional one or two equations are required for the turbulence model, which may have to be tuned for specific problems. We show that, in the case of the GHE, no additional turbulence model is needed, and the turbulent velocity profile is obtained from the GHE. The 2D turbulent channel and circular pipe flows were investigated using a numerical solution of the GHE for several cases. The solutions are compared with the experimental data in the circular pipes and 2D channels by Nicuradse (1932, Prandtl Lab), Hussain and Reynolds (1975), Wei and Willmarth (1989), Van Doorne (2007), theory by Wosnik, Castillo and George (2000), and the relevant experiments on Superpipe setup at Princeton, data by Zagarola (1996) and Zagarola and Smits (1998), the Reynolds number is from Re=7200 to Re=960000. The numerical solution data compared well with the experimental data, as well as with the approximate analytical solution for turbulent flow in channel Fedoseyev (2023). The obtained results confirm that the Alexeev generalized hydrodynamic theory (GHE) is in good agreement with the experiments for turbulent flows. The proposed approach is limited to 2D and 3D axisymmetric channel geometries. Further work will extend this approach by including channels with square and rectangular cross-sections.

Keywords: comparison with experimental data. generalized hydrodynamic equations, numerical solution, turbulent boundary layer, turbulent flow in channel

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Authors: Eva Kirzner

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Based on outcome studies published over the past two decades, in 2018, the ACC/AHA published new guidelines for the management of hypercholesterolemia that incorporate the use of coronary artery calcium (CAC) scanning as a decision tool for ascertaining which patients may benefit from statin therapy. This use is based on the recognition that the absence of calcium on CAC scanning (i.e., a CAC score of zero) usually signifies the absence of significant atherosclerotic deposits in the coronary arteries. Specifically, in patients with a high risk for atherosclerotic cardiovascular disease (ASCVD), initiation of statin therapy is generally recommended to decrease ASCVD risk. However, among patients with intermediate ASCVD risk, the need for statin therapy is less certain. However, there is a need for new outcome studies that provide evidence that the management of hypercholesterolemia based on these new ACC/AHA recommendations is safe for patients. Based on a Pub-Med and Google Scholar literature search, four relevant population-based or patient-based cohort studies that studied the relationship between CAC scanning, risk assessment or mortality, and statin therapy that were published between 2017 and 2021 were identified (see references). In each of these studies, patients were assessed for their baseline risk for atherosclerotic cardiovascular disease (ASCVD) using the Pooled Cohorts Equation (PCE), an ACC/AHA calculator for determining patient risk based on assessment of patient age, gender, ethnicity, and coronary artery disease risk factors. The combined findings of these four studies provided concordant evidence that a zero CAC score defines patients who remain at low clinical risk despite the non-use of statin therapy. Thus, these new studies confirm the use of CAC scanning as a safe tool for reducing the potential overuse of statin therapy among patients with zero CAC scores. Incorporating these new data suggest the following best practice: (1) ascertain ASCVD risk according to the PCE in all patients; (2) following an initial attempt trial to lower ASCVD risk with optimal diet among patients with elevated ASCVD risk, initiate statin therapy for patients who have a high ASCVD risk score; (3) if the ASCVD score is intermediate, refer patients for CAC scanning; and (4) and if the CAC score is zero among the intermediate risk ASCVD patients, statin therapy can be safely withheld despite the presence of an elevated serum cholesterol level.

Keywords: cholesterol, cardiovascular disease, statin therapy, coronary calcium

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Authors: Ben Nadler

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Cell adhesion plays a vital role in many cell activities. The motivation to model cell adhesion is to study important biological processes, such as cell spreading, cell aggregation, tissue formation, and cell adhesion, which are very challenging to study by experimental methods alone. This study provides important insight into cell adhesion, which can lead to improve regenerative medicine and tissue formation techniques. In this presentation the biological cells adhesion is mediated by receptors–ligands binding and the diffusivity of the receptor on the cell membrane surface. The ability of receptors to diffuse on the cell membrane surface yields a very unique and complicated adhesion mechanism, which is exclusive to cells. The phospholipid bilayer, which is the main component in the cell membrane, shows fluid-like behavior associated with the molecules’ diffusivity. The biological cell is modeled as a fluid-like membrane with negligible bending stiffness enclosing the cytoplasm fluid. The in-plane mechanical behavior of the cell membrane is assumed to depend only on the area change, which is motivated by the fluidity of the phospholipid bilayer. In addition, the presence of receptors influences on the local mechanical properties of the cell membrane is accounted for by including stress-free area change, which depends on the receptor density. Based on the physical properties of the receptors and ligands the attraction between the receptors and ligands is modeled as a charged-nonpolar which is a noncovalent interaction. Such interaction is a short-range type, which decays fast with distance. The mobility of the receptor on the cell membrane is modeled using the diffusion equation and Fick’s law is used to model the receptor–receptor interactions. The resultant interaction force, which includes receptor–ligand and receptor–receptor interaction, is decomposed into tangential part, which governs the receptor diffusion, and normal part, which governs the cell deformation and adhesion. The formulation of the governing equations and numerical simulations will be presented. Analysis of the adhesion characteristic and properties are discussed. The roles of various thermomechanical properties of the cell, receptors and ligands on the cell adhesion are investigated.

Keywords: cell adhesion, cell membrane, receptor-ligand interaction, receptor diffusion

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Authors: Tajinder Pal Singh

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Teaching of mathematics to engineering students is an open ended problem in education. The main goal of mathematics learning for engineering students is the ability of applying a wide range of mathematical techniques and skills in their engineering classes and later in their professional work. Most of the undergraduate engineering students and faculties feels that no efforts and attempts are made to demonstrate the applicability of various topics of mathematics that are taught thus making mathematics unavoidable for some engineering faculty and their students. The lack of understanding of concepts in engineering mathematics may hinder the understanding of other concepts or even subjects. However, for most undergraduate engineering students, mathematics is one of the most difficult courses in their field of study. Most of the engineering students never understood mathematics or they never liked it because it was too abstract for them and they could never relate to it. A right balance of application and concept based teaching can only fulfill the objectives of teaching mathematics to engineering students. It will surely improve and enhance their problem solving and creative thinking skills. In this paper, some practical (informal) ways of making mathematics-teaching application based for the engineering students is discussed. An attempt is made to understand the present state of teaching mathematics in engineering colleges. The weaknesses and strengths of the current teaching approach are elaborated. Some of the causes of unpopularity of mathematics subject are analyzed and a few pragmatic suggestions have been made. Faculty in mathematics courses should spend more time discussing the applications as well as the conceptual underpinnings rather than focus solely on strategies and techniques to solve problems. They should also introduce more ‘word’ problems as these problems are commonly encountered in engineering courses. Overspecialization in engineering education should not occur at the expense of (or by diluting) mathematics and basic sciences. The role of engineering education is to provide the fundamental (basic) knowledge and to teach the students simple methodology of self-learning and self-development. All these issues would be better addressed if mathematics and engineering faculty join hands together to plan and design the learning experiences for the students who take their classes. When faculties stop competing against each other and start competing against the situation, they will perform better. Without creating any administrative hassles these suggestions can be used by any young inexperienced faculty of mathematics to inspire engineering students to learn engineering mathematics effectively.

Keywords: application based learning, conceptual learning, engineering mathematics, word problem

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Authors: Mojo Mengistu Gelasso

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The tropical forest is considered the most important forest ecosystem for mitigating climate change by sequestering a high amount of carbon. The potential carbon stock of the forest can be influenced by many factors. Therefore, studying these factors is crucial for understanding the determinants that affect the potential for woody carbon storage in the forest. This study was conducted to evaluate the potential for woody carbon stock and how it varies based on plant community types, as well as along altitudinal, slope, and aspect gradients in the Munessa dry Afromontane forest. Vegetation data was collected using systematic sampling. Five line transects were established at 100 m intervals along the altitudinal gradient between two consecutive transect lines. On each transect, 10 quadrats (20 x 20 m), separated by 200 m, were established. The woody carbon was estimated using an appropriate allometric equation formulated for tropical forests. The data was analyzed using one-way ANOVA in R software. The results showed that the total woody carbon stock of the Munessa forest was 210.43 ton/ha. The analysis of variance revealed that woody carbon density varied significantly based on environmental factors, while community types had no significant effect. The highest mean carbon stock was found at middle altitudes (2367-2533 m.a.s.l), lower slopes (0-13%), and west-facing aspects. The Podocarpus falcatus-Croton macrostachyus community type also contributed a higher woody carbon stock, as larger tree size classes and older trees dominated it. Overall, the potential for woody carbon sequestration in this study was strongly associated with environmental variables. Additionally, the uneven distribution of species with larger diameter at breast height (DBH) in the study area might be linked to anthropogenic factors, as the current forest growth indicates characteristics of a secondary forest. Therefore, our study suggests that the development and implementation of a sustainable forest management plan is necessary to increase the carbon sequestration potential of this forest and mitigate climate change.

Keywords: munessa forest, woody carbon stock, environmental factors, climate mitigation

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Authors: Mengistu Gelasso Mojo

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The tropical forest is considered the most important forest ecosystem for mitigating climate change by sequestering a high amount of carbon. The potential carbon stock of the forest can be influenced by many factors. Therefore, studying these factors is crucial for understanding the determinants that affect the potential for woody carbon storage in the forest. This study was conducted to evaluate the potential for woody carbon stock and how it varies based on plant community types, as well as along altitudinal, slope, and aspect gradients in the Munessa dry Afromontane forest. Vegetation data was collected using systematic sampling. Five line transects were established at 100 m intervals along the altitudinal gradient between two consecutive transect lines. On each transect, 10 quadrats (20 x 20 m), separated by 200 m, were established. The woody carbon was estimated using an appropriate allometric equation formulated for tropical forests. The data was analyzed using one-way ANOVA in R software. The results showed that the total woody carbon stock of the Munessa forest was 210.43 ton/ha. The analysis of variance revealed that woody carbon density varied significantly based on environmental factors, while community types had no significant effect. The highest mean carbon stock was found at middle altitudes (2367-2533 m.a.s.l), lower slopes (0-13%), and west-facing aspects. The Podocarpus falcatus-Croton macrostachyus community type also contributed a higher woody carbon stock, as larger tree size classes and older trees dominated it. Overall, the potential for woody carbon sequestration in this study was strongly associated with environmental variables. Additionally, the uneven distribution of species with larger diameter at breast height (DBH) in the study area might be linked to anthropogenic factors, as the current forest growth indicates characteristics of a secondary forest. Therefore, our study suggests that the development and implementation of a sustainable forest management plan is necessary to increase the carbon sequestration potential of this forest and mitigate climate change.

Keywords: munessa forest, woody carbon stock, environmental factors, climate mitigation

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Authors: Hussein M. Etmimi, Peter E. Mallon

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Electrospinning uses an electrical charge to draw very fine fibers (typically on the micro or nano scale) from a liquid or molten precursor. Over the years, this method has become a widely used and a successful technique to process polymer materials and their composites into nanofibers. The main focus of this work is to study the electrospinning of multi-phase amphiphilic copolymers and their nanocomposites, which contain graphene as the nanofiller material. In such amphiphilic materials, the constituents segments are incompatible and thus the solid state morphology will be determined by the composition of the various constituents as well as the method of preparation. In this study, amphiphilic block copolymers of poly(dimethyl siloxane) and poly(methyl methacrylate) (PDMS-b-PMMA) with well-defined structures were synthesized and the solution electrospinning of these materials and their properties were investigated. Atom transfer radical polymerization (ATRP) was used to obtain the controlled block copolymers with relatively high molar masses and narrow dispersity. First, PDMS macroinitiators with different chain length of 1000, 5000 and 10000 g/mol were synthesized by the reaction of monocarbinol terminated PDMS with α-bromoisobutyryl bromide initiator. The obtained macroinitiators were used for the polymerization of methyl methacrylate monomer to obtain the desired block copolymers using the ATRP process. Graphene oxide (GO) of different loading was then added to the copolymer solution and the resultant nanocomposites were successfully electrospun into nanofibers. The electrospinning was achieved using dimethylformamide/chloroform mixture (60:40 vl%) as electrospinning solution medium. Scanning electron microscopy (SEM) showed the successful formation of the electrospun fibers with dimensions in the nanometer range. X-ray diffraction indicated that the GO nanosheets were of an exfoliated structure, irrespective of the filler loading. Thermogravimetric analysis also showed that the thermal stability of the nanofibers was improved in the presence of GO, which was not a function of the filler loading. Differential scanning calorimetry also showed that the mechanical properties (measured as glass transition temperature) of the nanofibers was improved significantly in the presence of GO, which was a function of the filler loading.

Keywords: elctrospinning, graphene oxide, nanofibers, polymethyl methacrylate (PMMA)

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Authors: Rawia M. Khalil, Ghada Abd-Elbary, Mona Basha, Ghada E. A. Awad, Hadeer A. Elhashemy

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Background: Bacterial infections of the eye are the clinical conditions responsible for ocular morbidity and blindness. Conjunctivitis is an inflammation of the conjunctiva, due to Staphylococcus aureus. Lomefloxacin HCl (LXN) is a third generation flouroquinolone antibiotic with a broad spectrum against wide range of bacteria and very effective against Staph infections especially in conjunctiva (conjunctivitis). The present study aims to develop and evaluate novel ocular proniosomal gels of Lomefloxacin Hcl (LXN); in order to improve its ocular bioavailability for the management of bacterial conjunctivitis. Materials and methods: Proniosomes were prepared by coacervation phase separation method using different types of nonionic surfactants (Span 60,40,20,Tween 20,40,60,80,Brij 35,98,72) solely and as mixtures with Span® 60. The formed gels were characterized for entrapment efficiency, vesicle size and in vitro drug release. The optimum proniosomal gel; P-LXN 7 were characterized for pH measurement, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) as well as Stability study and microbiological evaluation .The results revealed that only Span 60 was able to form stable LXN proniosomal gel when used individually while the other nonionic surfactants formed gels only in combination with Span 60 at different ratios. The optimum proniosomal gel; P-LXN 7 (Span60:Tween60, 9:1) appeared as spherical shaped vesicles having high entrapment efficiency (>80 %), appropriate vesicle size (187 nm) as well as controlled drug release over 12h. DSC confirmed the amorphous nature and the uniformity of LXN inclusion within the vesicles. Physical stability study did not show any significant changes in appearance or entrapment efficiency or vesicle size after storage for 3 months at 4°C. Ocular irritancy test revealed that P-LXN 7 was safe, well tolerable and suitable for ocular delivery. In vivo antibacterial activity of P-LXN 7 evaluated using the susceptibility test and topical therapy of induced ocular conjunctivitis confirmed the enhanced antibacterial therapeutic efficacy of the LXN-proniosomal gel compared to the commercially available LXN eye drops; Orchacin®. Conclusions: Our results suggest that proniosomal gels could provide a promising carrier of LXN for efficient ocular treatment of bacterial conjunctivitis.

Keywords: bacterial conjunctivitis, lomefloxacin HCl, ocular drug delivery, proniosomes

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Authors: Md. Akiz Uddin

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This research attempted to identify the determining factors that extensively persuaded customers of the First Security Islamic Bank Limited (FSIBL) to open accounts and their perception and satisfaction level towards it. Initially, a theoretical model was established based on existing literature reviews. After that, a self-administered structured questionnaire was developed, and data were collected from 180 customers of the FSIBL of Bangladesh using purposive sampling technique. The collected data were later analyzed through a statistical software. Structural Equation Modelling (SEM) was used to verify the model of the study and test the hypotheses. The study particularly examined the determinants of opening accounts, customers’ perception and their satisfaction level towards the bank on several factors like the bank’s compliance with Shariah law, use of modern technology, assurance, reliability, empathy, profitability, and responsiveness. To examine the impact of religious belief on being FSIBL clients, the study also investigates non-Muslim clients’ perception about FSIBL. The study focused on FSIBL customers only from five branches of Dhaka city. The study found that the religious beliefs is the most significant factors for Muslim customers for considering FSIBL to open an account, and they are satisfied with the services, too. However, for non-Muslim customers, other benefits like E-banking, various user-friendly services are the most significant factors for choosing FSIBL. Their satisfaction level is also statistically significant. Furthermore, even if the non- Muslim customers didn’t consider religious beliefs as determinant factors for choosing FSIBL, the respondents informed that they have trust that people who believe in shariah law are more reliable to keep money with them. These findings open up the avenue for future researchers to conduct more study in this area through employing a larger sample size and more branches and extending the current model by incorporating new variables. The study will be an important addition to the potentials of Islamic banking system, literature of service quality and customer satisfaction level, particularly in the success of Islamic banking system in Bangladesh.

Keywords: islamic banking, customers’ satisfaction, customers’ perception, shariah law

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Authors: Mohammad Mahdi Namdari, Hosein Torki

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Security as an abstract concept, has involved human being from the beginning of creation to the present, and certainly to the future. Accordingly, battles, conflicts, challenges, legal proceedings, crimes and all issues related to human kind are associated with this concept. Today by interviewing people about their life, the security of societies and Social crimes are interviewed too. Along with the security as an infrastructure and vital concept, the economy and related issues e.g. welfare, per capita income, total government revenue, export, import and etc. is considered another infrastructure and vital concept. These two vital concepts (Security and Economic) have linked together complexly and significantly. The present study employs analytical-descriptive research method using documents and Statistics of official sources. Discovery and explanation of this mutual connection are comprising a profound and extensive research; so management, development and reform in system and relationships of the scope of this two concepts are complex and difficult. Tourism and its position in today's economy is one of the main pillars of the economy of the 21st century that maybe associate with the security and social crimes more than other pillars. Like all human activities, economy of societies and partially tourism dependent on security especially in the public and social security. On the other hand, the true economic development (generally) and the growth of the tourism industry (dedicated) are a security generating and supporting for it, because a dynamic economic infrastructure prevents the formation of centers of crime and illegal activities by providing a context for socio-economic development for all segments of society in a fair and humane. This relationship is a formula of the complexity between the two concept of economy and security. Police as a revealed or people-oriented organization in the field of security directly has linked with the economy of a community and is very effective In the face of the tourism industry. The relationship between security and national crime index, and economic indicators especially ones related to tourism is confirming above discussion that is notable. According to understanding processes about security and economic as two key and vital concepts are necessary and significant for sovereignty of governments.

Keywords: economic, police, tourism, social security

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Authors: Hammad Majeed, Hanna Knuutila, Magne Hillestad, Hallvard F. Svendsen

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Formation of aerosols can cause serious complications in industrial exhaust gas CO2 capture processes. SO3 present in the flue gas can cause aerosol formation in an absorption based capture process. Small mist droplets and fog formed can normally not be removed in conventional demisting equipment because their submicron size allows the particles or droplets to follow the gas flow. As a consequence of this aerosol based emissions in the order of grams per Nm3 have been identified from PCCC plants. In absorption processes aerosols are generated by spontaneous condensation or desublimation processes in supersaturated gas phases. Undesired aerosol development may lead to amine emissions many times larger than what would be encountered in a mist free gas phase in PCCC development. It is thus of crucial importance to understand the formation and build-up of these aerosols in order to mitigate the problem. Rigorous modelling of aerosol dynamics leads to a system of partial differential equations. In order to understand mechanics of a particle entering an absorber an implementation of the model is created in Matlab. The model predicts the droplet size, the droplet internal variable profiles and the mass transfer fluxes as function of position in the absorber. The Matlab model is based on a subclass method of weighted residuals for boundary value problems named, orthogonal collocation method. The model comprises a set of mass transfer equations for transferring components and the essential diffusion reaction equations to describe the droplet internal profiles for all relevant constituents. Also included is heat transfer across the interface and inside the droplet. This paper presents results describing the basic simulation tool for the characterization of aerosols formed in CO2 absorption columns and gives examples as to how various entering droplets grow or shrink through an absorber and how their composition changes with respect to time. Below are given some preliminary simulation results for an aerosol droplet composition and temperature profiles.

Keywords: absorption columns, aerosol formation, amine emissions, internal droplet profiles, monoethanolamine (MEA), post combustion CO2 capture, simulation

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Authors: Francesca Alemanno

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As a complex socio-spatial phenomenon, migration is a practice that also contains a strong imaginative component with respect to the place that, through displacement, one person wants to reach. Every migrant has undertaken his journey having in his mind an image of the displacement he was about to make, of its implications and finally, of the place or city in which he was or would have liked to land. Often, however, the imaginary that has come to build before departure does not fully correspond to the reality of landing; this discrepancy, which can be more or less wide, plays an important role in the relationship that is established with the territory and in the evolution, therefore, of the city itself. In this sense, therefore, the clash that occurs between the imagined and the real is one of the factors that can contribute to making the entry of a migrant into new territory as critical as it can be. Starting from this perspective, the experiences of people who derive from a migratory context and who, over time, manage to create a bond with the land of reception, are taken into account as stories of resistance as they are necessarily charged with a force that is capable of driving difficult and articulated processes of change. The phenomenon of migrant entrepreneurship that is taken into consideration by this abstract plays a very important role because it highlights the story of many people who have managed to build such a close bond with the new territory of arrival that they can imagine and then realize the construction of their own personal business. The margin of contrast between the imagined city and the one that will be inhabited will be observed through the narratives of those who, through the realization of his business project has acted directly on the reality in which he landed. The margin of contrast that exists between the imagined city and the one actually inhabited, together with the implications that this may have on real life, has been observed and analyzed through a period of fieldwork, practicing ethnography, through the narratives of people who find themselves living in a new city as a result of a migration path, and has been contextualized with the support of semi-structured interviews and field notes. At the theoretical level, the research is inserted into a constructionist framework, particularly suited to detect and analyze processes of change, construction of the imaginary and its own modification, being able to capture the consequent repercussions of this process on the conceptual, emotional and practical level.

Keywords: entrepreneurship, imagination, migration, resistance

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Authors: Elizabeth Loza-Valerdi, Victor Pardiñas-Rios, Arnulfo Pluma-Pluma, Andres Breton-Toral, Julio Cercado-Jaramillo

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The purification processes for mixtures of isomeric monosaccharides using industrial chromatographic methods poses a serious technical challenge. Mixtures of 2 or 3 monosaccharides are difficult to separate by strictly physical or chemical techniques. Differential fermentation by microbial cultures is an increasingly interesting way of selective enrichment in a particular kind of monosaccharides when a mixture of them is present in the solution, and only one has economical value. Osmotolerant yeast cultures provide an interesting source of biocatalysts for the selective catabolism of monosaccharides in media containing high concentrations of total soluble sugars. A collection of 398 yeast strains has been obtained using endemic and unique sources of fruit juices, industrial syrups, honey, and other high sugar content substrates, either natural or man made, products and by-products from Mexico. The osmotolerance of the strains was assessed by plate assay both in glucose (20-40-60%w/w). Strains were classified according to their osmotolerance in low, medium or highly tolerant to high glucose concentrations. The purified cultures were tested by their ability to growth in a solid plate media or liquid media of Yeas Nitrogen Base (YNB), added with specific monosaccharides as sole carbon source (glucose, galactose, lactose and fructose). Selected strains were subsequently tested in fermentation experiments with mixtures of two monosaccharides (galactose/glucose and glucose/fructose). Their ability to grow and selectively catabolize one monosaccharide was evaluated. Growth, fermentation activity and products of metabolism were determined by plate counts, CO2 production, turbidity and chromatographic analysis by HPLC. Selective catabolism of one monosaccharide in liquid media containing two monosaccharides was confirmed for 8 strains. Ion Exchange chromatographic processes were used in production of high fructose or galactose syrup. Laboratory scale processes for the production of fructose or galactose enriched syrups is now feasible, with important applications in food (like high fructose syrup as edulcorant) and fermentation technology (for GOS production).

Keywords: osmotolerant yeasts, selective metabolism, fructose syrup, GOS

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Authors: Yananda Siraphatthada

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The objectives of this research were to study the level of influencing factors, leadership, supply chain management, innovation, competitive advantages, business success, and affecting factors to the business success of the mobile phone system service providers in Bangkok Metropolitan. This research was done by the quantitative approach and the qualitative approach. The quantitative approach was used for questionnaires to collect data from the 331 mobile service shop managers franchised by AIS, Dtac and TrueMove. The mobile phone system service providers/shop managers were randomly stratified and proportionally allocated into subgroups exclusive to the number of the providers in each network. In terms of qualitative method, there were in-depth interviews of 6 mobile service providers/managers of Telewiz and Dtac and TrueMove shop to find the agreement or disagreement with the content analysis method. Descriptive Statistics, including Frequency, Percentage, Means and Standard Deviation were employed; also, the Structural Equation Model (SEM) was used as a tool for data analysis. The content analysis method was applied to identify key patterns emerging from the interview responses. The two data sets were brought together for comparing and contrasting to make the findings, providing triangulation to enrich result interpretation. It revealed that the level of the influencing factors – leadership, innovation management, supply chain management, and business competitiveness had an impact at a great level, but that the level of factors, innovation and the business, financial success and nonbusiness financial success of the mobile phone system service providers in Bangkok Metropolitan, is at the highest level. Moreover, the business influencing factors, competitive advantages in the business of mobile system service providers which were leadership, supply chain management, innovation management, business advantages, and business success, had statistical significance at .01 which corresponded to the data from the interviews.

Keywords: mobile service providers, facilitating factors, Bangkok Metropolitan, business success

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Authors: H. Hammoudi, S. Bendenia, I. Batonneau-Gener, A. Khelifa

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Applying growing zeolites is due to their intrinsic physicochemical properties: a porous structure, regular, generating a large free volume, a high specific surface area, acidic properties of interest to the origin of their activity, selectivity energy and dimensional, leading to a screening phenomenon, hence the name of molecular sieves is generally attributed to them. Most of the special properties of zeolites have been valued as direct applications such as ion exchange, adsorption, separation and catalysis. Due to their crystalline structure stable, their large pore volume and their high content of cation X zeolites are widely used in the process of adsorption and separation. The acidic properties of zeolites X and interesting selectivity conferred on them their porous structure is also have potential catalysts. The study presented in this manuscript is devoted to the chemical modification of an X zeolite by cation exchange. Ion exchange of zeolite NaX by Zn 2 + cations and / or Cu 2 + is gradually conducted by following the evolution of some of its characteristics: crystallinity by XRD, micropore volume by nitrogen adsorption. Once characterized, the different samples will be used for the adsorption of propane and propylene. Particular attention is paid thereafter, on the modeling of adsorption isotherms. In this vein, various equations of adsorption isotherms and localized mobile, some taking into account the adsorbate-adsorbate interactions, are used to describe the experimental isotherms. We also used the Toth equation, a mathematical model with three parameters whose adjustment requires nonlinear regression. The last part is dedicated to the study of acid properties of Cu (x) X, Zn (x) X and CuZn (x) X, with the adsorption-desorption of pyridine followed by IR. The effect of substitution at different rates of Na + by Cu2 + cations and / or Zn 2 +, on the crystallinity and on the textural properties was treated. Some results on the morphology of the crystallites and the thermal effects during a temperature rise, obtained by scanning electron microscopy and DTA-TGA thermal analyzer, respectively, are also reported. The acidity of our different samples was also studied. Thus, the nature and strength of each type of acidity are estimated. The evaluation of these various features will provide a comparison between Cu (x) X, Zn (x) X and CuZn (x) X. One study on adsorption of C3H8 and C3H6 in NaX, Cu (x) X , Zn (x) x and CuZn (x) x has been undertaken.

Keywords: adsorption, acidity, ion exchange, zeolite

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Authors: Diana Peninger

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Over 10% of couples in the U.S. have infertility problems, with roughly 40% traceable to the male partner. Yet, little attention has been given to improving men’s contribution to the conception process. One solution that is showing promise in increasing conception rates for IVF and other assisted reproductive technology treatments is a first-of-its-kind semen collection that has been engineered to mitigate sperm damage caused by traditional collection methods. Patients are able to collect semen at home and deliver to clinics within 48 hours for use in fertility analysis and treatment, with less stress and improved specimen viability. This abstract will share these findings along with expert insight and tips to help attendees understand the key role sperm collection plays in addressing and treating reproductive issues, while helping to improve patient outcomes and success. Our research was to determine if male reproductive outcomes can be increased by improving sperm specimen health with a focus on technology. We utilized a redesigned semen collection cup (patented as the Device for Improved Semen Collection/DISC—U.S. Patent 6864046 – known commercially as a ProteX) that met a series of physiological parameters. Previous research demonstrated significant improvement in semen perimeters (motility forward, progression, viability, and longevity) and overall sperm biochemistry when the DISC is used for collection. Animal studies have also shown dramatic increases in pregnancy rates. Our current study compares samples collected in the DISC, next-generation DISC (DISCng), and a standard specimen cup (SSC), dry, with the 1 mL measured amount of media and media in excess ( 5mL). Both human and animal testing will be included. With sperm counts declining at alarming rates due to environmental, lifestyle, and other health factors, accurate evaluations of sperm health are critical to understanding reproductive health, origins, and treatments of infertility. An increase in the health of the sperm as measured by extensive semen parameter analysis and improved semen parameters stable for 48 hours, expanding the processing time from 1 hour to 48 hours were also demonstrated.

Keywords: reprodutive, sperm, male, infertility

Procedia PDF Downloads 119

Authors: Mostafa Sefidgar, Sohrab Zendehboudi, Hossein Bazmara, Madjid Soltani

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Based on findings from clinical applications, most drug treatments fail to eliminate malignant tumors completely even though drug delivery through systemic administration may inhibit their growth. Therefore, better understanding of tumor formation is crucial in developing more effective therapeutics. For this purpose, nowadays, solid tumor modeling and simulation results are used to predict how therapeutic drugs are transported to tumor cells by blood flow through capillaries and tissues. A solid tumor is investigated as a porous media for fluid flow simulation. Most of the studies use Darcy model for porous media. In Darcy model, the fluid friction is neglected and a few simplified assumptions are implemented. In this study, the effect of these assumptions is studied by considering Brinkman model. A multi scale mathematical method which calculates fluid flow to a solid tumor is used in this study to investigate how neglecting fluid friction affects the solid tumor simulation. In this work, the mathematical model in our previous studies is developed by considering two model of momentum equation for porous media: Darcy and Brinkman. The mathematical method involves processes such as fluid flow through solid tumor as porous media, extravasation of blood flow from vessels, blood flow through vessels and solute diffusion, convective transport in extracellular matrix. The sprouting angiogenesis model is used for generating capillary network and then fluid flow governing equations are implemented to calculate blood flow through the tumor-induced capillary network. Finally, the two models of porous media are used for modeling fluid flow in normal and tumor tissues in three different shapes of tumors. Simulations of interstitial fluid transport in a solid tumor demonstrate that the simplifications used in Darcy model affect the interstitial velocity and Brinkman model predicts a lower value for interstitial velocity than the values that Darcy model does.

Keywords: solid tumor, porous media, Darcy model, Brinkman model, drug delivery

Procedia PDF Downloads 287

Authors: K. Karuppasamy

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In this paper analysis of an infinite beam resting on multilayer tensionless extensible geosynthetic reinforced granular fill - poor soil system overlying soft soil strata under moving the load with constant velocity is presented. The beam is subjected to a concentrated load moving with constant velocity. The upper reinforced granular bed is modeled by a rough membrane embedded in Pasternak shear layer overlying a series of compressible nonlinear Winkler springs representing the underlying the very poor soil. The multilayer tensionless extensible geosynthetic layer has been assumed to deform such that at the interface the geosynthetic and the soil have some deformation. Nonlinear behavior of granular fill and the very poor soil has been considered in the analysis by means of hyperbolic constitutive relationships. Governing differential equations of the soil foundation system have been obtained and solved with the help of appropriate boundary conditions. The solution has been obtained by employing finite difference method by means of Gauss-Siedel iterative scheme. Detailed parametric study has been conducted to study the influence of various parameters on the response of soil – foundation system under consideration by means of deflection and bending moment in the beam and tension mobilized in the geosynthetic layer. These parameters include the magnitude of applied load, the velocity of the load, damping, the ultimate resistance of the poor soil and granular fill layer. The range of values of parameters has been considered as per Indian Railways conditions. This study clearly observed that the comparisons of multilayer tensionless extensible geosynthetic reinforcement with poor foundation soil and magnitude of applied load, relative compressibility of granular fill and ultimate resistance of poor soil has significant influence on the response of soil – foundation system. However, for the considered range of velocity, the response has been found to be insensitive towards velocity. The ultimate resistance of granular fill layer has also been found to have no significant influence on the response of the system.

Keywords: infinite beams, multilayer tensionless extensible geosynthetic, granular layer, moving load and nonlinear behavior of poor soil

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Authors: Lai Peng, Cristina Pintucci, Dries Seuntjens, José Carvajal-Arroyo, Siegfried Vlaeminck

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Economic incentives drive the implementation of short-cut nitrogen removal processes such as nitritation/denitritation (Nit/DNit) to manage nitrogen in waste streams devoid of biodegradable organic carbon. However, as any biological nitrogen removal process, the potent greenhouse gas nitrous oxide (N2O) could be emitted from Nit/DNit. Challenges remain in understanding the fundamental mechanisms and development of engineered mitigation strategies for N2O production. To provide answers, this work focuses on manure as a model, the biggest wasted nitrogen mass flow through our economies. A sequencing batch reactor (SBR; 4.5 L) was used treating the centrate (centrifuge supernatant; 2.0 ± 0.11 g N/L of ammonium) from an anaerobic digester processing mainly pig manure, supplemented with a co-substrate. Glycerin was used as external carbon source, a by-product of vegetable oil. Out-selection of nitrite oxidizing bacteria (NOB) was targeted using a combination of low dissolved oxygen (DO) levels (down to 0.5 mg O2/L), high temperature (35ºC) and relatively high free ammonia (FA) (initially 10 mg NH3-N/L). After reaching steady state, the process was able to remove 100% of ammonium with minimum nitrite and nitrate in the effluent, at a reasonably high nitrogen loading rate (0.4 g N/L/d). Substantial N2O emissions (over 15% of the nitrogen loading) were observed at the baseline operational condition, which were even increased under nitrite accumulation and a low organic carbon to nitrogen ratio. Yet, higher DO (~2.2 mg O2/L) lowered aerobic N2O emissions and weakened the dependency of N2O on nitrite concentration, suggesting a shift of N2O production pathway at elevated DO levels. Limiting the greenhouse gas emissions (environmental protection) from such a system could be substantially minimized by increasing the external carbon dosage (a cost factor), but also through the implementation of an intermittent aeration and feeding strategy. Promising steps forward have been presented in this abstract, yet at the conference the insights of ongoing experiments will also be shared.

Keywords: mitigation, nitrous oxide, nitritation/denitritation, pig manure

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Authors: Kevin Klein-Cardeña

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For Julia Kristeva, contra Lacan, the instinctive body refuses to go away within discourse. Neither is the pre-Oedipal stage of maternal fusion vanquished by the emergence of language and with it, the law of the father. On the contrary, Kristeva argues, the pre-symbolic ambivalently haunts the society of speech, simultaneously animating and threatening the very foundations of signification. Kristeva invents the term “the semiotic” to refer to this continual breaking-through of the material unconscious onto the scene of meaning. This presentation examines Kristeva’s semiotic as a theoretical gesture that itself is a disruption of discourse, re-presenting the ‘return of the repressed’ body in theory—-the breaking-through of the unconscious onto the science of meaning. Faced with linguistic theories concerned with abstract sign-systems as well as Lacanian doctrine privileging the linguistic sign unequivocally over the bodily drive, Kristeva’s theoretical corpus issues the message of a psychic remainder that disrupts with a view toward replenishing theoretical accounts of language and sense. Reviewing Semiotic challenge across these two levels (the sense and science of language), the presentation suggests that Kristeva’s offerings constitute a coherent gestalt, providing an account of the feminist nature of her dual intervention. In contrast to other feminist critiques, Kristeva’s gesture hinges on its restoration of the maternal contribution to subjectivity. Against the backdrop of ‘phallogocentric’ and ‘necrophilic’ theories that strip language of a subject and strip the subject of a body, Kristeva recasts linguistic study through a metaphor of life and birthing. Yet the semiotic fragments the subject it produces, dialoguing with an unconscious curtailed by but also exceeding the symbolic order of signification. Linguistics, too, becomes fragmented in the same measure as it is more meaningfully renewed by its confrontation with the semiotic body. It is Kristeva’s own body that issues this challenge, on both sides of the boundary between the theory and the theorized. The Semiotic becomes comprehensible as a project unified by its concern to disrupt and rehabilitate language, the subject, and the scholarly discourses that treat them.

Keywords: Julia kristeva, the Semiotic, french feminism, psychoanalysic theory, linguistics

Procedia PDF Downloads 59

Authors: F. Elhaouzi, H. Lahlali, M. Zaghrioui, I. El Aboudi A. BelfKira, A. Mdarhri

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The effect of physico chemical properties of solvents on the transport process and mechanical properties in elastomeric nano composite materials is reported. The investigated samples are formed by a semi-crystalline ethylene-co-butyl acrylate polymer filled with hard spherical carbon black (CB) nano particles. The swelling behavior was studied by immersion the dried samples in selected solvents at room temperature during 2 days. For this purpose, two chemical compounds methyl derivatives of aromatic hydrocarbons of benzene, i.e. toluene and xylene, are used to search for the mass and molar volume dependence on the absorption kinetics. Mass gain relative to the mass of dry material at specific times was recorded to probe the absorption kinetics. The transport of solvent molecules in these filled elastomeric composites is following a Fickian diffusion mechanism. Additionally, the swelling ratio and diffusivity coefficient deduced from the Fickian law are found to decrease with the CB concentration. These results indicate that the CB nano particles increase the effective path length for diffusion and consequently limit the absorption of the solvent by occupation free volumes in the material. According to physico chemical properties of the two used solvents, it is found that the diffusion is more important for the toluene molecules solvent due to their low values of the molecular weight and volume molar compared to those for the xylene. Differential Scanning Calorimetry (DSC) and X-ray photo electron (XPS) were also used to probe the eventual change in the chemical composition for the swollen samples. Mechanically speaking, the stress-strain curves of uniaxial tensile tests pre- and post- swelling highlight a remarkably decrease of the strength and elongation at break of the swollen samples. This behavior can be attributed to the decrease of the load transfer density between the matrix and the CB in the presence of the solvent. We believe that the results reported in this experimental investigation can be useful for some demanding applications e.g. tires, sealing rubber.

Keywords: nanocomposite, absorption kinetics, mechanical behavior, diffusion, modelling, XPS, DSC

Procedia PDF Downloads 343

Authors: Jude Harrison

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Child protection is a complex and sensitive practice. The core responsibility is the care and protection of children and young people who have been subject to or who are at risk from abuse and neglect. The work involves investigating allegations of harm, preparing for and making representations to the legal system, and case planning and management across a continuum of complicated care interventions. Professionals’ learning for child protection practice is evident in a range of literature investigating multiple learning processes such as university preparation, student placements, professional supervision, training, and other post-qualifying professional development experiences at work. There is, however, very limited research into how caseworkers learn in and through their daily practice. Little is known, therefore, about how learning at work unfolds for caseworkers, the dimensions in which it can be understood or the ways in which it can be best facilitated and supported. Compounding this, much of the current child protection learning literature reflects an orthodox conception of learning as mentalistic and individualised, in which knowledge is typically understood as abstract theory or as technical skill or competency. This presentation outlines key findings from a PhD research study that explored learning at work for statutory child protection caseworkers from an alternative interpretation of learning using a practice theory approach. Practice theory offers an interpretation of learning as performative and grounded in situated experience. The findings of the study show that casework practice is both a mode and site of learning. The study was ethnographic in design based and followed 17 child protection caseworkers via in-depth interviews, observations and participant reflective journaling. Inductive and abductive analysis was used to organise and interpret the data and expand analysis, leading to themes. Key findings show learning to be a sociomaterial property of doing; the social ontological character of learning; and teleoaffectivity as a feature of learning. The findings contribute to theoretical and practical understandings of learning and practice in child protection, child welfare and the professional learning literature more broadly. The findings have potential to contribute to policy directions at state, territory and national levels to enhance child protection practice and systems.

Keywords: adiult learning, workplace learning, child welfare, sociomaterial, practice theory

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Authors: Jožef Ritonja

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The biochemical industry is one of the most important modern industries. Biochemical reactors are crucial devices of the biochemical industry. The essential bioprocess carried out in bioreactors is the fermentation process. A thorough insight into the fermentation process and the knowledge how to control it are essential for effective use of bioreactors to produce high quality and quantitatively enough products. The development of the control system starts with the determination of a mathematical model that describes the steady state and dynamic properties of the controlled plant satisfactorily, and is suitable for the development of the control system. The paper analyses the fermentation process in bioreactors thoroughly, using existing mathematical models. Most existing mathematical models do not allow the design of a control system for controlling the fermentation process in batch bioreactors. Due to this, a mathematical model was developed and presented that allows the development of a control system for batch bioreactors. Based on the developed mathematical model, a control system was designed to ensure optimal response of the biochemical quantities in the fermentation process. Due to the time-varying and non-linear nature of the controlled plant, the conventional control system with a proportional-integral-differential controller with constant parameters does not provide the desired transient response. The improved adaptive control system was proposed to improve the dynamics of the fermentation. The use of the adaptive control is suggested because the parameters’ variations of the fermentation process are very slow. The developed control system was tested to produce dairy products in the laboratory bioreactor. A carbon dioxide concentration was chosen as the controlled variable. The carbon dioxide concentration correlates well with the other, for the quality of the fermentation process in significant quantities. The level of the carbon dioxide concentration gives important information about the fermentation process. The obtained results showed that the designed control system provides minimum error between reference and actual values of carbon dioxide concentration during a transient response and in a steady state. The recommended control system makes reference signal tracking much more efficient than the currently used conventional control systems which are based on linear control theory. The proposed control system represents a very effective solution for the improvement of the milk fermentation process.

Keywords: biochemical reactor, fermentation process, modelling, adaptive control

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Authors: Shrawan Baghel, Helen Cathcart, Biall J. O'Reilly

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Amorphous drug formulations have great potential to enhance solubility and thus bioavailability of BCS class II drugs. However, the higher free energy and molecular mobility of the amorphous form lowers the activation energy barrier for crystallization and thermodynamically drives it towards the crystalline state which makes them unstable. Accurate determination of the crystallization tendency/kinetics is the key to the successful design and development of such systems. In this study, dipyridamole (DPM) and cinnarizine (CNZ) has been selected as model compounds. Thermodynamic fragility (m_T) is measured from the heat capacity change at the glass transition temperature (Tg) whereas dynamic fragility (m_D) is evaluated using methods based on extrapolation of configurational entropy to zero 〖(m〗_(D_CE )), and heating rate dependence of Tg 〖(m〗_(D_Tg)). The mean relaxation time of amorphous drugs was calculated from Vogel-Tammann-Fulcher (VTF) equation. Furthermore, the correlation between fragility and glass forming ability (GFA) of model drugs has been established and the relevance of these parameters to crystallization of amorphous drugs is also assessed. Moreover, the crystallization kinetics of model drugs under isothermal conditions has been studied using Johnson-Mehl-Avrami (JMA) approach to determine the Avrami constant ‘n’ which provides an insight into the mechanism of crystallization. To further probe into the crystallization mechanism, the non-isothermal crystallization kinetics of model systems was also analysed by statistically fitting the crystallization data to 15 different kinetic models and the relevance of model-free kinetic approach has been established. In addition, the crystallization mechanism for DPM and CNZ at each extent of transformation has been predicted. The calculated fragility, glass forming ability (GFA) and crystallization kinetics is found to be in good correlation with the stability prediction of amorphous solid dispersions. Thus, this research work involves a multidisciplinary approach to establish fragility, GFA and crystallization kinetics as stability predictors for amorphous drug formulations.

Keywords: amorphous, fragility, glass forming ability, molecular mobility, mean relaxation time, crystallization kinetics, stability

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Authors: Amir Mukhtar, Habib Nasir

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To achieve an enhanced range of large calibre artillery a base bleed unit equipped with ammonium perchlorate and hydroxyl-terminated polybutadiene (AP/HTPB) based composite propellant grain is installed at the bottom of a projectile which produces jet of hot gasses and reduces base drag during flight of the projectile. Upon leaving the muzzle at very high muzzle velocity, due to sudden pressure drop, the propellant grain gets quenched. Therefore, base-bleed unit is equipped with an igniter to ensure ignition as well as reignition of the propellant grain. Pyrotechnic compositions based on Zr/NH₄ClO₄ and Zr/KClO₄ mixtures have been studied for the effect of fuel/oxidizer ratio and oxidizer type on ballistic properties. Calorific values of mixtures were investigated by bomb calorimeter, the average burning rate was measured by fuse wire technique at ambient conditions, and high-pressure closed vessel was used to record pressure-time profile, maximum pressure achieved (Pmax), time to achieve Pmax and differential pressure (dP/dt). It was observed that the 30, 40, 50 and 60 wt.% of Zr has a very significant effect on ballistic properties of mixtures. Compositions with NH₄ClO₄ produced higher values of Pmax, dP/dt and Calorific value as compared to Zr/KClO₄ based mixtures. Composition containing KClO₄ comparatively produced higher burning rate and maximum burning rate was recorded at 8.30 mm/s with 60 wt.% Zr in Zr/KClO₄ pyrotechnic mixture. Zr/KClO₄ with 50 wt. % of Zr was tests fired in igniter assembly by electric initiation method. Igniter assembly was test fired several times and average burning time of 3.5 sec with igniter mass burning rate of 6.85 g/sec was recorded. Igniter was finally fired on static and dynamic level with base bleed unit which gave successful ignition to the base bleed grain and extended range was achieved with 155 mm artillery projectile.

Keywords: base bleed, closed vessel, igniter, zirconium

Procedia PDF Downloads 146

Authors: Ranadhir Roy

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Inverse problems arise in medical (molecular) imaging. These problems are characterized by large in three dimensions, and by the diffusion equation which models the physical phenomena within the media. The inverse problems are posed as a nonlinear optimization where the unknown parameters are found by minimizing the difference between the predicted data and the measured data. To obtain a unique and stable solution to an ill-posed inverse problem, a priori information must be used. Mathematical conditions to obtain stable solutions are established in Tikhonov’s regularization method, where the a priori information is introduced via a stabilizing functional, which may be designed to incorporate some relevant information of an inverse problem. Effective determination of the Tikhonov regularization parameter requires knowledge of the true solution, or in the case of optical imaging, the true image. Yet, in, clinically-based imaging, true image is not known. To alleviate these difficulties we have applied the penalty/modified barrier function (PMBF) method instead of Tikhonov regularization technique to make the inverse problems well-posed. Unlike the Tikhonov regularization method, the constrained optimization technique, which is based on simple bounds of the optical parameter properties of the tissue, can easily be implemented in the PMBF method. Imposing the constraints on the optical properties of the tissue explicitly restricts solution sets and can restore uniqueness. Like the Tikhonov regularization method, the PMBF method limits the size of the condition number of the Hessian matrix of the given objective function. The accuracy and the rapid convergence of the PMBF method require a good initial guess of the Lagrange multipliers. To obtain the initial guess of the multipliers, we use a least square unconstrained minimization problem. Three-dimensional images of fluorescence absorption coefficients and lifetimes were reconstructed from contact and noncontact experimentally measured data.

Keywords: constrained minimization, ill-conditioned inverse problems, Tikhonov regularization method, penalty modified barrier function method

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Authors: Morenikeji Aliu Balaji

Abstract:

Gender inequality is seen as persistent discrimination of one group of people based gender, and it manifests itself differently according to race, culture, politics, country and economic situation. Multiple explanations have been offered for gender differences in literacy skill development. Three prominent explanations that precipitated the gender differences are; biological, where the assumption is that differential brain structures and hemispheric activation patterns cause the sexes to be hardwired differently for reading, with girls developing the cognitive skills associated with reading before boys. Secondly, schooling favour girls and ‘girly’ behaviour, and that boys are, as a result, lagging behind on several behavioural, social and academic measures and thirdly, cultural influences, where literacy is defined as a feminine characteristic – propagated by an overrepresentation of female teachers – and that modern culture steers boys towards activities such as sport and computers. Therefore the study investigated the influence of gender inequality on pre – primary school children literacy skills development in Ojo Local Government Area, Lagos State. Descriptive survey research design was adopted for the study. 100 pre-primary school teachers were involved in the study. A self-designed instrument was used for data collection titled ‘Influence of Gender Inequality on Literacy Skill Development in Children Questionnaire (IGILSDCQ)’. The instrument was validated and tested for reliability. The reliability index for IGILSDCQ (α = 0.79). Five research questions were answered using descriptive (frequency count, simple percentage, mean and standard deviation). The findings showed that that gender inequality to some extent influence children phonemic awareness (WA=1.76), the extent to which gender inequality influence children awareness of print is high (WA=2.8), gender inequality to some extent influence children vocabulary development (WA = 2.4), the extent to which gender inequality influence children speaking skill development is high (WA = 2.5) and lastly, the extent to which gender inequality influence children comprehension ability is high (WA = 2.5). It was recommended among others that effort by the school administrators is necessary in the provision of reading materials and literacy skill development packages that are both male-oriented and female-oriented.

Keywords: pre-primart, literacy, awareness, phonemic, gender

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