Search results for: endometrial blood flow

Authors: Aihong Zhao, Priya Sastry, Mark L Field, Mohamad Bashir, Arvind Singh, David Richens

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Objectives: Intramural haematoma (IMH) is one of the pathologies, along with acute aortic dissection, that present as Acute Aortic Syndrome (AAS). Evidence suggests that unlike aortic dissection, some intramural haematomas may regress with medical management. However, intramural haematomas have been traditionally managed like acute aortic dissections. Given that some of these pathologies may regress with conservative management, it would be useful to be able to identify which of these may not need high risk emergency intervention. A computational aortic model was used in this study to try and identify intramural haematomas with risk of progression to aortic dissection. Methods: We created a computational model of the aorta with luminal blood flow. Reports in the literature have identified 11 mm as the radial clot thickness that is associated with heightened risk of progression of intramural haematoma. Accordingly, haematomas of varying sizes were implanted in the modeled aortic wall to test this hypothesis. The model was exposed to physiological blood flows and the stresses and strains in each layer of the aortic wall were recorded. Results: Size and shape of clot were seen to affect the magnitude of aortic stresses. The greatest stresses and strains were recorded in the intima of the model. When the haematoma exceeded 10 mm in all dimensions, the stress on the intima reached breaking point. Conclusion: Intramural clot size appears to be a contributory factor affecting aortic wall stress. Our computer simulation corroborates clinical evidence in the literature proposing that IMH diameter greater than 11 mm may be predictive of progression. This preliminary report suggests finite element modelling of the aortic wall may be a useful process by which to examine putative variables important in predicting progression or regression of intramural haematoma.

Keywords: intramural haematoma, acute aortic syndrome, finite element analysis,

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Authors: Siveshnee Devar

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Background: The rate of absenteeism and prevalence of NCDs in South Africa is extremely high. This is consistent with other educational institutions and workplaces around the globe. In most cases the absence of health and the presence of one or more non communicable diseases coupled with the lack of physical exercise is a major factor in absenteeism. Absenteeism at the workplace comes at a huge cost to the employer and the country as a whole. Aim: Findings from this study was to develop a suitable nutritional wellness program for the workplace. Methodology: A needs analysis in the form of 24-hour recall, food frequency, health and socio demographic questionnaires was undertaken to determine the need for a wellness program for the institution. Anthropometric indices such as BMI, waist circumference and blood pressure were also undertaken to determine the state of health of the staff. Results: This study has found that obesity, central obesity, hypertension as well as deficiencies in nutrients and minerals were prevalent in this group. Fruit and vegetable consumption was also below the WHO recommendation. This study showed a link between diet, physical activity and diseases of lifestyle. There were positive correlations between age and systolic blood pressure, waist circumference and systolic blood pressure, waist circumference and diastolic blood pressure and waist-to-height ratio and BMI. Conclusion: The results indicated the need for immediate intervention in the form of a wellness program. Nutrition education is important for both the workplace and out. Education and knowledge are important factors for lifestyle changes. The proposed intervention is aimed at improving presenteeism and decreasing the incidence of non- communicable diseases. Presenteeism and good health are important factors for quality education at all educational institutions.

Keywords: absenteeism, non-communicable diseases, nutrition, wellness

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Authors: Natalia V. Minaeva, Natalia A. Zorina, Marina N. Khorobrikh, Philipp S. Sherstnev, Tatiana V. Krivokorytova, Alexander S. Luchinin, Maksim S. Minaev, Igor V. Paramonov

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Background. Over the last few decades, the Center for International Blood and Marrow Transplant Research (CIBMTR) and the World Marrow Donor Association (WMDA) have been actively working to ensure the safety of the hematopoietic stem cell (HSC) donation process. Registration of adverse events that may occur during the donation period and establishing a relationship between donation and side effects are included in the WMDA international standards. The level of blood serum N-terminal pro-brain natriuretic peptide (NT-proBNP) is an early marker of myocardial stress. Due to the high analytical sensitivity and specificity, laboratory assessment of NT-proBNP makes it possible to objectively diagnose myocardial dysfunction. It is well known that the main stimulus for proBNP synthesis and secretion from atrial and ventricular cardiac myocytes is myocyte stretch and increasement of myocardial extensibility and pressure in the heart chambers. Аim. The aim of the study was to assess the dynamic changes in the levels of blood serum N-terminal pro-brain natriuretic peptide of unrelated donors at various stages of hematopoietic stem cell mobilization. Materials. We have examined 133 unrelated donors, including 92 men and 41 women, that have been included into the study. The NT-proBNP levels were measured before the start of mobilization, then on the day of apheresis, and after the donation of allogeneic HSC. The relationship between NT-proBNP levels and body mass index (BMI), ferritin, hemoglobin, and white blood cells (WBC) levels was assessed on the day of apheresis. The median age of donors was 34 years. Mobilization of HSCs was managed with filgrastim administration at a dose of 10 μg/kg daily for 4-5 days. The first leukocytapheresis was performed on day 4 from the start of filgrastim administration. Quantitative values of the blood serum NT-proBNP level are presented as a median (Me), first and third quartiles (Q1-Q3). Comparative analysis was carried out using the t-test and correlation analysis as well by Spearman method. Results. The baseline blood serum NT-proBNP levels in all 133 donors were within the reference values (<125 pg/ml) and equaled 21,6 (10,0; 43,3) pg/ml. At the same time, the level of NT-proBNP in women was significantly higher than that of men. On the day of the HSC apheresis, a significant increase of blood serum NT-proBNP levels was detected and equald 131,2 (72,6; 165,3) pg/ml (p<0,001), with higher rates in female donors. A statistically significant weak inverse correleation was established between the level of NT-proBNP and the BMI of donors (-0.18, p = 0,03), as well as the level of hemoglobin (-0.33, p <0,001), and ferritin levels (-0.19, p = 0,03). No relationship has been established between the magnitude of WBC levels achieved as a result of the mobilization of HSC on the day of leukocytapheresis. A day after the apheresis, the blood serum NT-proBNP levels still exceeded the reference values, but there was a decreasing tendency. Conclusion. An increase of the blood serum NT-proBNP level in unrelated donors during the mobilization of HSC was established. Future studies should clarify the reason for this phenomenon, as well as its effects on donors' long-term health.

Keywords: unrelated donors, mobilization, hematopoietic stem cells, N-terminal pro-brain natriuretic peptide

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Authors: Farhan Aljuaidi

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The rapid expansion of Alkarj city, Saudi Arabia, towards the outlet of Wadi AlAin is critical for the planners and decision makers. Nowadays, two major projects such as Salman bin Abdulaziz University compound and new industrial area are developed in this flood prone area where no channels are clear and identified. The main contribution of this study is to divert the flow away from these vital projects by reconstructing new channels. To do so, Lidar data were used to generate contour lines for the actual elevation of the highways and local roads. These data were analyzed and compared to the contour lines derived from the topographical maps 1:50.000. The magnitude of the expected flow was estimated using Snyder's Model based on the morphometric data acquired by DEM of the catchment area. The results indicate that maximum discharge peak reaches 2694,3 m3/sec, the mean is 303,7 m3/sec and the minimum is 74,3 m3/sec. The runoff was estimated at 252,2. 610 m3/s, the mean is 41,5. 610 m3/s and the minimum is 12,4. 610 m3/s.

Keywords: Desert flood, Saudi Arabia, Snyder's Model, flow estimation

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Authors: Gwi Hyun Lee, Mun Soo Na

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Solar energy has many advantages of infinite and clean source, and also it can be used for reduction of greenhouse gases and environment pollution. Concentrated solar system is a very useful to achieve reasonably high thermal efficiency. Different types of solar concentrating systems have been developed such as parabolic trough and parabolic dish. Conical solar concentrator is one of the most reliable and promising renewable energy systems for higher temperature applications. The objectives of this study were to investigate the influence of flow rate affecting the thermal efficiency of a conical solar collector, which has a double tube absorber placed at focal axis for collecting solar radiation. A conical solar concentrator consists of a conical reflector, which reflects direct solar radiation into an absorber. A double tube absorber was placed at the center of focal axis for collecting the solar radiation reflected from a conical reflector. A dual tracking system consists of a linear actuator and slew drive with driving cycle of 6 seconds. Water was used as circulating fluid, which flows from inlet to outlet of an absorber for collecting solar radiation. Three identical conical solar concentrator systems were installed side by side at the same place for the accurate performance analysis under the same environmental conditions. Performance evaluations were carried out with different volumetric flow rate of 2, 4 and 6 L/min to find the influence of flow rate affecting on thermal efficiency. The results indicated that average thermal efficiency was 73.24%, 81.96%, and 79.78% for each flow rate of 2 L/min, 4 L/min, and 6 L/min. It shows that the flow rate of circulating water has a significant effect on the thermal efficiency of the conical solar concentrator. It is concluded that an optimum flow rate of conical solar concentrator is 6 L/min.

Keywords: conical solar concentrator, performance evaluation, solar energy, solar energy system

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Authors: A. B. Disu, M. S. Dada

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This study was conducted to investigate two dimensional heat transfer of a free convective-radiative MHD (Magneto-hydrodynamics) flow with temperature dependent viscosity and heat source of a viscous incompressible fluid in a porous medium between two vertical wavy walls. The fluid viscosity is assumed to vary as an exponential function of temperature. The flow is assumed to consist of a mean part and a perturbed part. The perturbed quantities were expressed in terms of complex exponential series of plane wave equation. The resultant differential equations were solved by Differential Transform Method (DTM). The numerical computations were presented graphically to show the salient features of the fluid flow and heat transfer characteristics. The skin friction and Nusselt number were also analyzed for various governing parameters.

Keywords: differential transform method, MHD free convection, porous medium, two dimensional radiation, two wavy walls

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Authors: Mohamed Abdelwahed

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We propose an optimization algorithm for the geometric control of fluid flow. The used approach is based on the topological sensitivity analysis method. It consists in studying the variation of a cost function with respect to the insertion of a small obstacle in the domain. Some theoretical and numerical results are presented in 2D and 3D.

Keywords: sensitivity analysis, topological gradient, shape optimization, stokes equations

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Authors: Mohammed A. Arishy, Sultan M. Alharbi, Mohammed A. Hakami, Farid M. Abualsail, Mohammad A. Attafi, Riyadh M. Tobaiqi, Hussain M. Alsalem, Ibraheem M. Attafi

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Lidocaine is the most common local anesthetics used for para cervical block to reduce pain associated with surgical abortion. A 25-year-old pregnant woman who. She died before reaching hospital, and she was undergoing criminal abortion during the first trimester. In post-mortem investigations and autopsy shows no clear finding; therefore, toxic substances must be suspected and searched for routinely toxicology analysis. In this case report, the postmortem concentration of lidocaine was detected blood, brain, liver, kidney, and stomach. For lidocaine identification and quantification, sample was extracted using solid phase extraction and analyzed by GC-MS (Shimadzu, Japan). Initial screening and confirmatory analysis results showed that only lidocaine was detected in all collected samples, and no other toxic substances or alcohol were detected. The concentrations of lidocaine in samples were 19, 17, 14, 7, and 3 ug/m in the brain, blood, kidney, liver, and stomach, respectively. Lidocaine blood concentration (17 ug/ml) was toxic level and may result in death. Among the tissues, brain showed the highest level of lidocaine, followed by the kidney, liver, and stomach.

Keywords: forensic toxicology, GC-MS, lidocaine, postmortem

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Authors: R. Osada, S. Ogata, T. Segawa

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Dielectric barrier discharge plasma actuators (DBD-PAs) have been developed for active flow control devices. However, it is necessary to reduce ozone produced by DBD toward practical applications using DBD-PAs. In this study, variations of ozone concentration, flow velocity, power consumption were investigated by changing exposed electrodes of DBD-PAs. Two exposed electrode prototypes were prepared: span-type with exposed electrode width of 0.1 mm, and normal-type with width of 5 mm. It was found that span-type shows lower power consumption and higher flow velocity than that of normal-type at V_p-p = 4.0-6.0 kV. Ozone concentration of span-type higher than normal-type at V_p-p = 4.0-8.0 kV. In addition, it was confirmed that catalyst located in downstream from the exposed electrode can reduce ozone concentration between 18 and 42% without affecting the induced flow.

Keywords: dielectric barrier discharge plasma actuators, ozone diffusion, PIV measurement, power consumption

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Authors: Foad Vashahi, Shahnaz Rezaei, Jeekeun Lee

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Large Eddy Simulation (LES) was performed on a dual counter rotating axial swirler in a confined rectangular configuration. Grids were constructed based on a primary Reynolds Averaged Navier-Stokes (RANS) simulation and then were refined based on the Kolmogorov length scale. Water as cold flow condition was applied and results were compared via Particle Image Velocimetry (PIV) experimental results. The focus was to investigate the flow behavior within the region before the flare and very close to the exit of the swirler. This region contributes to a highly unsteady flow behavior and requires great attention to enhancing the flame stability in gas turbine combustor and swirl burners. The PVC formation within the central core flow is strongly related to the peaks of pressure or axial velocity spectrum and up to two distinct peaks at the swirler mouth could be observed. Here, spectra analysis in iso-thermal condition inside the swirler where the inner swirler dominates the flow, showed a higher potential of instabilities with three to four distinct peaks where moving forward to the exit of swirler the number of peaks is decreased. In addition to this, the central axis corresponds to no peaks of instabilities while further away in the radial direction, several peaks exist.

Keywords: axial counter rotating swirler, large eddy simulation (LES), precessing vortex core (PVC), power spectral density (PSD)

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Authors: Razi Khalafi

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Myocardial Infarction (MI) or acute Myocardial Infarction (AMI), commonly known as a heart attack, occurs when blood flow stops to part of the heart causing damage to the heart muscle. An ECG can often show evidence of a previous heart attack or one that's in progress. The patterns on the ECG may indicate which part of your heart has been damaged, as well as the extent of the damage. In chaos theory, the correlation dimension is a measure of the dimensionality of the space occupied by a set of random points, often referred to as a type of fractal dimension. In this research by considering ECG signal as a random walk we work on forecasting the oncoming heart attack by analysing the ECG signals using the correlation dimension. In order to test the model a set of ECG signals for patients before and after heart attack was used and the strength of model for forecasting the behaviour of these signals were checked. Results show this methodology can forecast the ECG and accordingly heart attack with high accuracy.

Keywords: heart attack, ECG, random walk, correlation dimension, forecasting

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Authors: Mohamed Sarrab, Hadj Bourdoucen

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Mobile applications are verified to check the correctness or evaluated to check the performance with respect to specific security properties such as availability, integrity, and confidentiality. Where they are made available to the end users of the mobile application is achievable only to a limited degree using software engineering static verification techniques. The more sensitive the information, such as credit card data, personal medical information or personal emails being processed by mobile application, the more important it is to ensure the confidentiality of this information. Monitoring non-trusted mobile application during execution in an environment where sensitive information is present is difficult and unnerving. The paper addresses the issue of monitoring and controlling the flow of confidential information during non-trusted mobile application execution. The approach concentrates on providing a dynamic and usable information security solution by interacting with the mobile users during the run-time of mobile application in response to information flow events.

Keywords: mobile application, run-time verification, usable security, direct information flow

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Authors: Etsuo Morishita

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In this paper, we show shallow water in a tin box as an analogous simulation tool for high-speed aerodynamics education and research. It is customary that we use a water tank to create shallow water flow. While a flow in a water tank is not necessarily uniform and is sometimes wavy, we can visualize a clear supercritical flow even when we move a body manually in stationary water in a simple shallow tin box. We can visualize a blunt shock wave around a moving circular cylinder together with a shock pattern around a diamond airfoil. Another interesting analogous experiment is a hydrodynamic shock tube with water and tea. We observe the contact surface clearly due to color difference of the two liquids those are invisible in the real gas dynamics experiment. We first revisit the similarities between high-speed aerodynamics and shallow water hydraulics. Several educational and research experiments are then introduced for engineering students. Shallow water experiments in a tin box simulate properly the high-speed flows.

Keywords: aerodynamics compressible flow, gas dynamics, hydraulics, shock wave

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Authors: Zhiyuan Tang, Ju Zhang, Wenyuan Wu

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In this research, a car-following model with consideration of the status of the brake light is proposed. The numerical results show that the stability of the traffic flow is improved. The ability of the brake light to reduce car accident is also showed.

Keywords: brake light, car-following model, traffic flow, regional planning, transportation

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Authors: Bahram Talebjedi, Amirmohammad Sattari, Ahmed Zoher Sihorwala, Mina Hoorfar

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Among different droplet manipulations, controlled droplet-splitting is of great significance due to its ability to increase throughput and operational capability. Furthermore, unequal droplet-splitting can provide greater flexibility and a wider range of dilution factors. In this study, we developed two-dimensional, time-dependent complex fluid dynamics simulations to model droplet formation in a flow focusing device, followed by splitting in a Y-shaped junction with sub-channels of unequal widths. From the results obtained from the numerical study, we correlated the diameters of the droplets in the sub-channels to the Weber number, thereby demarcating the droplet splitting and non-splitting regimes.

Keywords: microfluidics, unequal droplet splitting, two phase flow, flow focusing device

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Authors: Safia Akram

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The influence of nanofluid with different waveforms in the presence of inclined asymmetric channel on peristaltic transport of a pseudoplastic fluid is examined. The governing equations for two-dimensional and two directional flows of a pseudoplastic fluid along with nanofluid are modeled and then simplified under the assumptions of long wavelength and low Reynolds number approximation. The exact solutions for temperature and nanoparticle volume fraction are calculated. Series solution of the stream function and pressure gradient are carried out using perturbation technique. The flow quantities have been examined for various physical parameters of interest. It was found, that the magnitude value of the velocity profile decreases with an increase in volume flow rate (Q) and relaxation times (ζ) and increases in sinusoidal, multisinusoidal, trapezoidal and triangular waves. It was also observed that the size of the trapping bolus decreases with the drop of the width of the channel ‘d’ and increases with a rise of relaxation times ζ.

Keywords: nanofluid particles, peristaltic flow, pseudoplastic fluid, different waveforms, inclined asymmetric channel

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Authors: M. Guen

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A three-dimensional numerical study is used to analyze the behavior of the flow inside a vortex tube. The vortex tube or Ranque-Hilsch vortex tube is a simple device which is capable of dividing compressed air from the inlet nozzle tangentially into two flow with different temperatures warm and cold. This phenomenon is known from literature by temperature separation. The K ω-SST and K-ε turbulence models are used to predict the turbulent flow behaviour inside the tube. The vortex tube is an Exair 708 slpm (25 scfm) commercial tube. The cold and hot exits areas are 30.2 and 95 mm2 respectively. The vortex nozzle consists of 6 straight slots; the height and the width of each slot are 0.97 mm and 1.41 mm. The total area normal to the flow associated with six nozzles is therefore 8.15 mm 2. The present study focuses on a comparison between two turbulence models K ω-SST, K-ε by using a new configuration of vortex tube (Conical Vortex Tube). The performance curves of the temperature separation versus cold outlet mass fraction were calculated and compared with experimental and numerical study of other researchers.

Keywords: conical vortex tube, temperature separation, cold mass fraction, turbulence

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Authors: Farzana Esmailkassam, Usakorn Kunanuvat, Zahraa Mohammed Ali

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Objective: The key barrier in Clozapine treatment of treatment-resistant schizophrenia (TRS) includes frequent bloods draws to monitor neutropenia, the main drug side effect. WBC and ANC monitoring must occur throughout treatment. Accurate WBC and ANC counts are necessary for clinical decisions to halt, modify or continue clozapine treatment. The CSAN Pronto point-of-care (POC) analyzer generates white blood cells (WBC) and absolute neutrophils (ANC) through image analysis of capillary blood. POC monitoring offers significant advantages over central laboratory testing. This study evaluated the performance of the CSAN Pronto against the Beckman DxH900 Hematology laboratory analyzer. Methods: Forty venous samples (EDTA whole blood) with varying concentrations of WBC and ANC as established on the DxH900 analyzer were tested in duplicates on three CSAN Pronto analyzers. Additionally, both venous and capillary samples were concomitantly collected from 20 volunteers and assessed on the CSAN Pronto and the DxH900 analyzer. The analytical performance including precision using liquid quality controls (QCs) as well as patient samples near the medical decision points, and linearity using a mix of high and low patient samples to create five concentrations was also evaluated. Results: In the precision study for QCs and whole blood, WBC and ANC showed CV inside the limits established according to manufacturer and laboratory acceptability standards. WBC and ANC were found to be linear across the measurement range with a correlation of 0.99. WBC and ANC from all analyzers correlated well in venous samples on the DxH900 across the tested sample ranges with a correlation of > 0.95. Mean bias in ANC obtained on the CSAN pronto versus the DxH900 was 0.07× 109 cells/L (95% L.O.A -0.25 to 0.49) for concentrations <4.0 × 109 cells/L, which includes decision-making cut-offs for continuing clozapine treatment. Mean bias in WBC obtained on the CSAN pronto versus the DxH900 was 0.34× 109 cells/L (95% L.O.A -0.13 to 0.72) for concentrations <5.0 × 109 cells/L. The mean bias was higher (-11% for ANC, 5% for WBC) at higher concentrations. The correlations between capillary and venous samples showed more variability with mean bias of 0.20 × 109 cells/L for the ANC. Conclusions: The CSAN pronto showed acceptable performance in WBC and ANC measurements from venous and capillary samples and was approved for clinical use. This testing will facilitate treatment decisions and improve clozapine uptake and compliance.

Keywords: absolute neutrophil counts, clozapine, point of care, white blood cells

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Authors: Adil Rasheed, Mandar Tabib

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The paper describes the ability of a high-resolution Computational Fluid Dynamics model to predict terrain-induced turbulence and wind shear close to the ground. Various sensitivity studies to choose the optimal simulation setup for modeling the flow characteristics in a complex terrain are presented. The capabilities of the model are demonstrated by applying it to the Sandnessjøen Airport, Stokka in Norway, an airport that is located in a mountainous area. The model is able to forecast turbulence in real time and trigger an alert when atmospheric conditions might result in high wind shear and turbulence.

Keywords: aviation safety, terrain-induced turbulence, atmospheric flow, alert system

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Authors: Norhaslina Mat Zian, Hasril Hasini, Nur Irmawati Om

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This study focuses on the flow and combustion behavior inside gas turbine combustor used in thermal power plant. The combustion process takes place using synthetic gas and the baseline solution was made on gas turbine combustor firing natural gas (100% Methane) as the main source of fuel. Attention is given to the effect of the H2/CO ratio on the variation of the flame profile, temperature distribution, and emissions. The H2/CO ratio varies in the range of 10-80 % and the CH4 values are fixed 10% for each case. While keeping constant the mass flow rate and operating pressure, the preliminary result shows that the flow inside the can-combustor is highly swirling which indicates good mixing of fuel and air prior to the entrance of the mixture to the main combustion zone.

Keywords: cfd, combustion, flame, syngas

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Authors: M. Abdur Rashid Sarkar, Riffat Mahmud

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Boiling heat transfer plays a crucial role in cooling nuclear reactor for safe electricity generation. A two phase flow is susceptible to thermal-hydrodynamic instabilities, which may cause flow oscillations of constant amplitude or diverging amplitude. These oscillations may induce boiling crisis, disturb control systems, or cause mechanical damage. Based on their mechanisms, various types of instabilities can be classified for a nuclear reactor. From a practical engineering point of view one of the major design difficulties in dealing with multiphase flow is that the mass, momentum, and energy transfer rates and processes may be quite sensitive to the geometric configuration of the heat transfer surface. Moreover, the flow within each phase or component will clearly depend on that geometric configuration. The complexity of this two-way coupling presents a major challenge in the study of multiphase flows and there is much that remains to be done. Yet, the parametric effects on flow instability such as the effect of aspect ratio, pressure drop, channel length, its orientation inlet subcooling and surface roughness etc. have been analyzed. Another frequently occurring instability, known as the Kelvin–Helmholtz instability has been briefly reviewed. Various analytical techniques for predicting parametric effect on the instability are analyzed in terms of their applicability and accuracy.

Keywords: two phase flows, boiling crisis, thermal-hydrodynamic instabilities, water cooled nuclear reactors, kelvin–helmholtz instability

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Authors: Imen Latrous

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Family firm is the most common form of business organization in the world. Many family businesses rely heavily on their own capital to finance their expansion. This dependence on internal funds for their investment may be deliberate to maintain the family dominant position or involuntary as family firms have limited access to external funds. Our understanding of family firm’s choice to fund their own growth using existing capital is somewhat limited. The aim of this paper is to study whether the presence of a controlling family in the company either mitigates or exacerbates external financing constraints. The impact of family ownership on investment–cash flow sensitivity is ultimately an empirical question. We use a sample of 406 Canadian firms listed in Toronto Stock exchange (TSX) over the period 2005–2014 in order to explore this relationship. We distinguish between three elements in the definition of family firms, specifically ownership, control and management, to explore the issue whether family firms are more efficient organisational form. Our research contributes to the extant literature on family ownership in several ways. First, as our understanding of family firm’s investment cash flow sensitivity is somewhat limited in recession times, we explore the effect of family firms on the relation between investment and cash flow during the recent 2007-2009 financial crisis. We also analyse this relationship difference between family firms and non family firms before and during financial crisis. Finally, our paper addresses the endogeneity problem of family ownership and investment-cash flow sensitivity.

Keywords: family firms, investment–cash flow sensitivity, financial crisis, corporate governance

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Authors: Rei-Tang Tsai, Chih-Yang Wu, Chia-Yuan Chang, Ming-Ying Kuo

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This study aims to investigate the mixing behaviors of deionized (DI) water and carboxymethyl cellulose (CMC) solutions in C-shaped serpentine micromixers over a wide range of flow conditions. The flow of CMC solutions exhibits shear-thinning behaviors. Numerical simulations are performed to investigate the effects of the mean flow speed, fluid properties and geometry parameters on flow and mixing in the micromixers with serpentine channel of the same overall channel length. From the results, we can find the following trends. When fluid mixing is dominated by convection, the curvature-induced vortices enhance fluid mixing effectively. The mixing efficiency of a micromixer consisting of semicircular C-shaped repeating units with a smaller center-line radius is better than that of a micromixer consisting of major-segment repeating units with a larger center-line radius. The viscosity of DI water is less than the overall average apparent viscosity of CMC solutions, and so the effect of curvature-induced vortices on fluid mixing in DI water is larger than that in CMC solutions for the cases with the same mean flow speed.

Keywords: curved channel, microfluidics, mixing, non-newtonian fluids, vortex

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Authors: Li Ji, Kaiwei Chu, Shibo Kuang, Aibing Yu

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Hydrocyclones are widely used to classify particles by size in industries such as mineral processing and chemical processing. The particles to be handled usually have a broad range of size distributions and sometimes density distributions, which has to be properly considered, causing challenges in the modelling of hydrocyclone. The combined approach of Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) offers convenience to model particle size/density distribution. However, its direct application to hydrocyclones is computationally prohibitive because there are billions of particles involved. In this work, a CFD-DEM model with the concept of the coarse-grained (CG) model is developed to model the solid-fluid flow in a hydrocyclone. The DEM is used to model the motion of discrete particles by applying Newton’s laws of motion. Here, a particle assembly containing a certain number of particles with same properties is treated as one CG particle. The CFD is used to model the liquid flow by numerically solving the local-averaged Navier-Stokes equations facilitated with the Volume of Fluid (VOF) model to capture air-core. The results are analyzed in terms of fluid and solid flow structures, and particle-fluid, particle-particle and particle-wall interaction forces. Furthermore, the calculated separation performance is compared with the measurements. The results obtained from the present study indicate that this approach can offer an alternative way to examine the flow and performance of hydrocyclones

Keywords: computational fluid dynamics, discrete element method, hydrocyclone, multiphase flow

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Authors: Sasitharan Ambicapathy, J. Vignesh, P. Sivaraj, Godfrey Derek Sams, K. Sabarinath, V. R. Sanal Kumar

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The external flow simulation of a flying car at take off phase is a daunting task owing to the fact that the prediction of the transient unsteady flow features during its deployment phase is very complex. In this paper 3D numerical simulations of external flow of Ferrari F430 proposed flying car with different NACA 9618 rectangular wings have been carried. Additionally, the aerodynamics characteristics have been generated for optimizing its geometry for achieving the minimum take off velocity with better overall performance in both road and air. The three-dimensional standard k-omega turbulence model has been used for capturing the intrinsic flow physics during the take off phase. In the numerical study, a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier-Stokes equations is employed. Through the detailed parametric analytical studies we have conjectured that Ferrari F430 flying car facilitated with high wings having three different deployment histories during the take off phase is the best choice for accomplishing its better performance for the commercial applications.

Keywords: aerodynamics of flying car, air taxi, negative lift, roadable airplane

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Authors: Urvi Panwar, Kanchan Mishra, Kanjaksha Ghosh, ShankerLal Kothari

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Background: Day-by-day the increasing prevalence of neurodegenerative diseases have become a global issue to manage them by medical sciences. The adult neural stem cells are rare and require an invasive and painful procedure to obtain it from central nervous system. Mesenchymal stem cell (MSCs) therapies have shown remarkable application in treatment of various cell injuries and cell loss. MSCs can be derived from various sources like adult tissues, human bone marrow, umbilical cord blood and cord tissue. MSCs have similar proliferation and differentiation capability, but the human umbilical cord-derived mesenchymal stem cells (hUCMSCs) are proved to be more beneficial with respect to cell procurement, differentiation to other cells, preservation, and transplantation. Material and method: Human umbilical cord is easily obtainable and non-controversial comparative to bone marrow and other adult tissues. The umbilical cord can be collected after delivery of baby, and its tissue can be cultured using explant culture method. Cell culture medium such as DMEMF12+10% FBS and DMEMF12+Neural growth factors (bFGF, human noggin, B27) with antibiotics (Streptomycin/Gentamycin) were used to culture and differentiate mesenchymal stem cells into neural cells, respectively. The characterisations of MSCs were done with Flow Cytometer for surface markers CD90, CD73 and CD105 and colony forming unit assay. The differentiated various neural cells will be characterised by fluorescence markers for neurons, astrocytes, and oligodendrocytes; quantitative PCR for genes Nestin and NeuroD1 and Western blotting technique for gap43 protein. Result and discussion: The high quality and number of MSCs were isolated from human umbilical cord via explant culture method. The obtained MSCs were differentiated into neural cells like neurons, astrocytes and oligodendrocytes. The differentiated neural cells can be used to treat neural injuries and neural cell loss by delivering cells by non-invasive administration via cerebrospinal fluid (CSF) or blood. Moreover, the MSCs can also be directly delivered to different injured sites where they differentiate into neural cells. Therefore, human umbilical cord is demonstrated to be an inexpensive and easily available source for MSCs. Moreover, the hUCMSCs can be a potential source for neural cell therapies and neural cell regeneration for neural cell injuries and neural cell loss. This new way of research will be helpful to treat and manage neural cell damages and neurodegenerative diseases like Alzheimer and Parkinson. Still the study has a long way to go but it is a promising approach for many neural disorders for which at present no satisfactory management is available.

Keywords: bone marrow, cell therapy, explant culture method, flow cytometer, human umbilical cord, mesenchymal stem cells, neurodegenerative diseases, neuroprotective, regeneration

Procedia PDF Downloads 201

Authors: Kaila A. Vento

Abstract:

Within the field of sports science, financial situations have been reported as a key barrier in purchasing high-quality foods. A lack of proper nutrition leads to insecurities of health, impairs training, and diminishes optimal performances. Consequently, insufficient nutrient intake, disordered eating patterns, and eating disorders may arise, leading to poor health and well-being. Athletic scholarships, nutrition resources, and meal programs are available, yet are disproportionally allocated, favoring male sports, Caucasian athletes, and higher sport levels. Direct athlete finances towards nutrition at various sport levels and the role race influences aid received has yet to be examined. Additionally, a diverse female athlete population is missing in the sports science literature, specifically in nutrition. To address this gap, the current project assesses how financial and nutrition support and nutrition knowledge impacts physical health, dietary intake, and overall quality of life of a diverse sample of female athletes at the National Collegiate Athletic Association (NCAA), National Junior Collegiate Athletic Association (NJCAA), and cub sport levels. The project will identify differences in financial support in relation to race, as well. Approximately (N = 120) female athletes will participate in a single 30-minute lab visit. At this visit, body composition (i.e., height, weight, body mass index, and fat percent), blood health indicators (fasted blood glucose and lipids), and resting blood pressure are measured. In addition, three validated questionnaires pertaining to nutrition knowledge (Sports Nutrition Knowledge Questionnaire; SNKQ), dietary intake (Rapid Eating Assessment for Participants; REAP), and quality of life (World Health Organization Quality of Life Brief; WHOQL-B) are gathered. Body composition and blood health indicators will be compared with the results of self-reported sports nutrition knowledge, dietary intake, and quality of life questionnaires. It is hypothesized that 1) financial and nutrition support and nutrition knowledge will differ between the sport levels and 2) financial and nutrition support and nutrition knowledge will have a positive association with quality of dietary intake and blood health indicators, 3) financial and nutrition support will differ significantly among racial background across the various competition levels, and 4) dietary intake will influence blood health indicators and quality of life. The findings from this study could have positive implications on athletic associations' policies on equity of financial and nutrition support to improve the health and safety of all female athletes across several sport levels.

Keywords: athlete, equity, finances, health, resources

Procedia PDF Downloads 101

Authors: Ahmed Salisu Atiku

Abstract:

This task involves the determination of the flow arrangement for optimum performance and the calculation of total heat transfer of two identical double pipe heat exchangers in series. The inner pipe contains the cold water stream at 27°C, whilst the outer pipe contains the two hot stream of water at 50°C and 90 °C which can be mixed in any way desired. The analysis was carried out using counter flow arrangement due to its good heat transfer ability. The best way of heating this cold stream was found out to be passing the 90°C hot stream through the two heat exchangers. The outlet temperature of the cold stream was found to be 39.6°C and overall heat transfer of 131.3 kW. Though starting with 50°C hot stream in the first heat exchanger followed by 90°C hot stream in the second heat exchanger gives an outlet temperature almost the same as 90°C hot stream alone, but the heat transfer is low. The reason for the low heat transfer was that only the heat transfer in the second heat exchanger is considered. Whilst the reason behind high outlet temperature was that the cold stream was already preheated by the first stream.

Keywords: cold stream, flow arrangement, heat exchanger, hot stream

Procedia PDF Downloads 321

Authors: Santhita Tungkajiwangkoon, Yoshikazu Hoshi

Abstract:

Three Japaneses Drosera species are the good model to study genome organization with highly specialized morphological group for insect trapping, and has revealed anti-inflammatory, and antibacterial effects, so there must be a reason for botanists are so appealing in these plants. Cytology and Flow cytometry were used to investigate the genetic stability and ploidy estimation in three related species. The cytological and Flow cytometry analysis were done in Drosera rotundifolia L., Drosera spatulata Labill and Drosera tokaiensis. The cytological studies by fluorescence staining (DAPI) showed that D. tokaiensis was an alloploid (2n=6x=60, hexaploid) which is a natural hybrid polyploids of D. rotundifolia and D. spatulata. D. rotundifolia was a diploid with the middle size of metaphase chromosomes (2n=2x=20) as a paternal origin and D. spatulata was a tetraploid with small size of metaphase chromosome (2n=4x=40) as a maternal origin. We confirmed by Flow cytometry analysis to determine the ploidy level and DNA content of the plants. The 2C-DNA values of D. rotundiflolia were 2.8 pg, D. spatulata was 1.6 pg and D. tokaiensis was 3.9 pg. However, 2C- DNA values of D. tokaiensis should be related from their parents but in the present study the 2C-DNA values of D. tokaiensis was no relation from the theoretical of hybrids representing additive parental. Possibility of D. tokaiensis is a natural hybrid, which is also hybridization in natural evolution can cause the genome reduction in plant.

Keywords: drosera, hybrid, cytology, flow cytometry

Procedia PDF Downloads 378

Authors: Gyo Woo Lee, Man Young Kim

Abstract:

Emission regulations for diesel engines are being strengthened and it is impossible to meet the standards without exhaust after-treatment systems. Lack of the space in many diesel vehicles, however, make it difficult to design and install stand-alone catalytic converters such as DOC, DPF, and SCR in the vehicle exhaust systems. Accordingly, those have been installed inside the muffler to save the space, and referred to the catalytic muffler. However, that has complex internal structure with perforated plate and pipe for noise and monolithic catalyst for emission reduction. For this reason, flow uniformity and pressure drop, which affect efficiency of catalyst and engine performance, respectively, should be examined when the catalytic muffler is designed. In this work, therefore, the flow uniformity and pressure drop to improve the performance of the catalytic converter and the engine have been numerically investigated by changing various design parameters such as inlet shape, porosity, and outlet shape of the muffler using the three-dimensional turbulent flow of the incompressible, non-reacting, and steady state inside the catalytic muffler. Finally, it can be found that the shape, in which the muffler has perforated pipe inside the inlet part, has higher uniformity index and lower pressure drop than others considered in this work.

Keywords: catalytic muffler, perforated inlet cone, catalysts, perforated pipe, flow uniformity, pressure drop

Procedia PDF Downloads 322