Search results for: breaking length

Authors: Karima Boukhadia

Abstract:

In the present study, the subsonic flow in an asymmetrical diffuser was simulated numerically using code CFX 11.0 and its generator of grid ICEM CFD. Two models of turbulence were tested: K- ε and K- ω SST. The results obtained showed that the K- ε model singularly over-estimates the speed value close to the wall and that the K- ω SST model is qualitatively in good agreement with the experimental results of Buice and Eaton 1997. They also showed that the separation and reattachment of the fluid on the tilted wall strongly depends on its angle of inclination and that the length of the zone of separation increases with the angle of inclination of the lower wall of the diffuser.

Keywords: asymmetric diffuser, separation, reattachment, tilt angle, separation zone

Procedia PDF Downloads 576

Authors: Donald G. Danmeier, Gian Marco Pizzo, Matthew Brennan

Abstract:

Although wetlands have been proposed as a green alternative to manage coastal flood hazards because of their capacity to adapt to sea level rise and provision of multiple ecological and social co-benefits, they are often overlooked due to challenges in quantifying the uncertainty and naturally, variability of these systems. This objective of this study was to quantify wave attenuation provided by a natural marsh surrounding a large oil refinery along the US Gulf Coast that has experienced steady erosion along the shoreward edge. The vegetation module of the SWAN was activated and coupled with a hydrodynamic model (DELFT3D) to capture two-way interactions between the changing water level and wavefield over the course of a storm event. Since the marsh response to relative sea level rise is difficult to predict, a range of future marsh morphologies is explored. Numerical results were examined to determine the amount of wave attenuation as a function of marsh extent and the relative contributions from white-capping, depth-limited wave breaking, bottom friction, and flexing of vegetation. In addition to the coupled DELFT3D-SWAN modeling of a storm event, an uncoupled SWAN-VEG model was applied to a simplified bathymetry to explore a larger experimental design space. The wave modeling revealed that the rate of wave attenuation reduces for higher surge but was still significant over a wide range of water levels and outboard wave heights. The results also provide insights to the minimum marsh extent required to fully realize the potential wave attenuation so the changing coastal hazards can be managed.

Keywords: green infrastructure, wave attenuation, wave modeling, wetland

Procedia PDF Downloads 132

Authors: Ja’afar Umar, Adamu Aliyu Aliero

Abstract:

Plant growth, biochemical parameters, zinc metal concentrations were determined for Capsicum frutescens L. in response to varied concentration of zinc metal. The plant exhibited a decline in the vegetative parameters measured. Free proline and glycine betaine content increases with increasing concentration of zinc metal and differ significantly (P<0.05). It can be concluded that the osmolyte (pro and GB) accumulations, and high length of stem and wide leaf expansion are possible indicator of tolerance to heavy metals (Zinc) in Capsicum frutescens.

Keywords: zinc metal, osmolyte, Capsicum frutescens, stress

Procedia PDF Downloads 485

Authors: Amy Guidera, Steven Busby, Christian Williams, David Phillippi

Abstract:

College students are a priority preventative healthcare population that can engage in high-risk behaviors which may concurrently increase the potential for unsafe sexual practices, including contracting sexually transmitted infections (STIs). Early education, screening, treatment, and partner notification are important interventions for breaking the chain of transmission and recurrence in relation to preventing poor health outcomes and mitigating college dropout rates. The aim of this quality improvement project was to determine if the reduction in STI screening costs for college students (aged 18-30 years old) would increase the amount of STI screenings conducted at a university health center over the course of an academic semester while evaluating our ability to achieve an improved quality of care at a reduced cost, along with improved STI reporting and documentation. This study was conducted through retrospective chart reviews of STI-related visits and utilized the RADAR matrix to provide a guiding, iterative mechanism to continuously reassess goals and outcomes defined in a memorandum of agreement (MOA) between a university health center and the state department of health (DOH) laboratory. The project failed to increase the amount of STI screenings, most likely due to the emergence of COVID-19, but resulted in improved quality of care for students, improved STI-related visit documentation and reporting, and significantly reduced costs for STI screening for collegiate students at a southeastern private university campus.

Keywords: college health, college students, preventive health, reproductive health, sexually transmitted infections, young adults

Procedia PDF Downloads 135

Authors: A. Bekbaev, M. Dzhamanbaev, R. Abitaeva, A. Karbozova, G. Nabyeva

Abstract:

In this paper, the regression dependence of dancing intensity from wind speed and length of span was established due to the statistic data obtained from multi-year observations on line wires dancing accumulated by power systems of Kazakhstan and the Russian Federation. The lower and upper limitations of the equations parameters were estimated, as well as the adequacy of the regression model. The constructed model will be used in research of dancing phenomena for the development of methods and means of protection against dancing and for zoning plan of the territories of line wire dancing.

Keywords: power lines, line wire dancing, dancing intensity, regression equation, dancing area intensity

Procedia PDF Downloads 312

Authors: Emine Şahin, Murat Soner Balcıoğlu

Abstract:

The aim of this study was to determine the growth hormone (bGH) gene polymorphism in the Holstein cattle growing around Antalya in Turkey. In order to determine the bGH-AluI polymorphism, polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) method was performed. A 891 bp fragment of bGH was amplified and two types of alleles C and D for bGH were observed. In this study, the frequencies of C and D alleles were 0.8438 and 0.1562, respectively. The genotype frequencies for CC, CD and DD were 0.787, 0.191 and 0.022, respectively. According to the results of the chi-square test, a significant deviation from the Hardy-Weinberg equilibrium was not determined for the bGH locus in the population.

Keywords: Growth Hormone Gene, Holstein , Polymorphism, RFLP

Procedia PDF Downloads 371

Authors: Fekadu Gadissa, Kassahun Tesfaye, Kifle Dagne, Mulatu Geleta

Abstract:

‘Ethiopian dinich’ also called ‘Ethiopian potato’ is one of the economically important ‘orphan’ edible tuber crops indigenous to Ethiopia. We evaluated the morphological and agronomic traits performances of 174 samples from Ethiopia at multiple locations using 12 qualitative and 16 quantitative traits, recorded at the correct growth stages. We observed several morphotypes and phenotypic variations for qualitative traits along with a wide range of mean performance values for all quantitative traits. Analysis of variance for each quantitative trait showed a highly significant (p<0.001) variation among the collections with eventually non-significant variation for environment-traits interaction for all but flower length. A comparatively high phenotypic and genotypic coefficient of variation was observed for plant height, days to flower initiation, days to 50% flowering and tuber number per hill. Moreover, the variability and coefficients of variation due to genotype-environment interaction was nearly zero for all the traits except flower length. High genotypic coefficients of variation coupled with a high estimate of broad sense heritability and high genetic advance as a percent of collection mean were obtained for tuber weight per hill, number of primary branches per plant, tuber number per hill and number of plants per hill. Association of tuber yield per hectare of land showed a large magnitude of positive phenotypic and genotypic correlation with those traits. Principal components analysis revealed 76% of the total variation for the first six principal axes with high factor loadings again from tuber number per hill, number of primary branches per plant and tuber weight. The collections were grouped into four clusters with the weak region (zone) of origin based pattern. In general, there is high genetic-based variability for ‘Ethiopian dinich’ improvement and conservation. DNA based markers are recommended for further genetic diversity estimation for use in breeding and conservation.

Keywords: agro-morphological traits, Ethiopian dinich, genetic diversity, variance components

Procedia PDF Downloads 190

Authors: Kachout Mnaouer, Bel Hadj Tahar Jamel, Choubani Fethi

Abstract:

In this paper, three electric equivalent models to evaluate crosstalk between three-conductor transmission lines are proposed. First, electric equivalent models for three-conductor transmission lines are presented. Secondly, rigorous equations to calculate the per-unit length inductive and capacitive parameters are developed. These models allow us to calculate crosstalk between conductors. Finally, to validate the presented models, we compare the theoretical results with simulation data. Obtained results show that proposed models can be used to predict crosstalk performance.

Keywords: near-end crosstalk, inductive parameter, L, Π, T models

Procedia PDF Downloads 451

Authors: C. Busuioc, S. I. Jinga, E. Pavel

Abstract:

The continuous need of more non-volatile memories with a higher storage capacity, smaller dimensions and weight, as well as lower costs, has led to the exploration of optical lithography on active media, as well as patterned magnetic composites. In this context, optical lithography is a technique that can provide a significant decrease of the information bit size to the nanometric scale. However, there are some restrictions that arise from the need of breaking the optical diffraction limit. Major achievements have been obtained by employing a vitoceramic material as active medium and a laser beam operated at low power for the direct writing procedure. Thus, optical discs with ultra-high density were fabricated by a conventional melt-quenching method starting from analytical purity reagents. They were subsequently used for 3D recording based on their photosensitive features. Naturally, the next step consists in the elucidation of the composition and structure of the active centers, in correlation with the use of silver and rare-earth compounds for the synthesis of the optical supports. This has been accomplished by modern characterization methods, namely transmission electron microscopy coupled with selected area electron diffraction, scanning transmission electron microscopy and electron energy loss spectroscopy. The influence of laser diode parameters, silver concentration and fluorescent compounds formation on the writing process and final material properties was investigated. The results indicate performances in terms of capacity with two order of magnitude higher than other reported information storage systems. Moreover, the fluorescent photosensitive vitroceramics may be integrated in other applications which appeal to nanofabrication as the driving force in electronics and photonics fields.

Keywords: data storage, fluorescent compounds, laser writing, vitroceramics

Procedia PDF Downloads 225

Authors: Ann Enright

Abstract:

More than ever, animal shelters need to identify ways to reduce the number of animals entering shelter facilities and the incidence of euthanasia. Managing animal overpopulation using euthanasia can have detrimental health and emotional consequences for the shelter staff involved. There are also community expectations with moral and financial implications to consider. To achieve the goals of reducing animal intake and the incidence of euthanasia, shelter best practice involves combining programs, procedures and partnerships to increase live release rates (LRR), reduce the incidence of disease, length of stay (LOS) and shelter intake whilst overall remaining financially viable. Analysing daily processes, tracking outcomes and implementing simple strategies enabled shelter staff to more effectively focus their efforts and achieve amazing results. The objective of this retrospective study was to assess the effect of implementing the capacity for care (C4C) management model. Data focusing on the average daily number of animals on site for a two year period (2016 – 2017) was exported from a shelter management system, Customer Logic (CL) Vet to Excel for manipulation and comparison. Following the implementation of C4C practices the average daily number of animals on site was reduced by >50%, (2016 average 103 compared to 2017 average 49), average LOS reduced by 50% from 8 weeks to 4 weeks and incidence of disease reduced from ≥ 70% to less than 2% of the cats on site at the completion of the study. The total number of stray cats entering the shelter due to council contracts reduced by 50% (486 to 248). Improved cat outcomes were attributed to strategies that increased adoptions and reduced euthanasia of poorly socialized cats, including foster programs. To continue to achieve improvements in LRR and LOS, strategies to decrease intake further would be beneficial, for example, targeted sterilisation programs. In conclusion, the study highlighted the benefits of using C4C as a management tool, delivering a significant reduction in animal intake and euthanasia with positive emotional, financial and community outcomes.

Keywords: animal welfare, capacity for care, cat, euthanasia, length of stay, managed intake, shelter

Procedia PDF Downloads 139

Authors: B. Daheche, M. T. Hannachi, H. Djebaili

Abstract:

In this approach, we tried to describe the flare test tubes welded by high frequency induction HF, and its experimental application. The test is carried out ENTTPP (National company of pipe mill and processing of flat products). Usually, the final products (tube) undergo a series of destructive testing (CD) in order to see the efficiency of welding. This test performed on sections of pipe with a length defined in the notice is made under a determined effort (pressure), which depends on its share of other parameters namely mechanical (fracture resistance) and geometry (thickness tube, outside diameter), the variation of this effort is well researched and recorded.

Keywords: flare, destructive testing, pressure, drafts tube, tube finished

Procedia PDF Downloads 317

Authors: Khosro Barkhordari, Fateme Sadr, Mina Pashang

Abstract:

Back ground: Blood transfusion is one of the major issues in cardiac surgery patients. Transfusing patients based on fixed cut-off points of hemoglobin is the current protocol in most institutions. The hemoglobin level of 7- 10 has been suggested for blood transfusion in cardiac surgery patients. We aimed to evaluate if blood transfusion based on change in percentage of hematocrit has different outcomes. Methods: In this retrospective cohort study, we investigated the early postoperative outcome of cardiac surgery patients who received blood transfusions at Tehran Heart Center Hospital, IRAN. We reviewed and analyzed the basic characteristics and clinical data of 700 patients who met our exclusion and inclusion criteria. The two groups of blood transfused patients were compared, those who have 30-50 percent decrease in basal hematocrit versus those with 10 -29 percent decrease. Results: This is ongoing study, and the results would be completed in two weeks after analysis of the date. Conclusion: Early analysis has shown no difference in early post-operative outcomes between the two groups, but final analysis will be completed in two weeks. 1-Department of Anesthesiology and Critical Care, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IRAN 2- Department of Research, Tehran Heart Center, Tehran, IRAN Quantitative variables were compared using the Student t-test or the Mann‐Whitney U test, as appropriate, while categorical variables were compared using the χ2 or the Fisher exact test, as required. Our intention was to compare the early postoperative outcomes between the two groups, which include 30 days mortality, Length of ICU stay, Length of hospital stay, Intubation time, Infection rate, acute kidney injury, and respiratory complications. The main goal was to find if transfusing blood based on changes in hematocrit from a basal level was better than to fixed cut-off point regarding early post-operative outcomes. This has not been studied enough and may need randomized control trials.

Keywords: post-operative, cardiac surgery, outcomes, blood transfusion

Procedia PDF Downloads 86

Authors: Marielle Leijten, Catherine Meulemans, Sven De Maeyer, Luuk Van Waes

Abstract:

For the diagnosis of Alzheimer's disease (AD), a large variety of neuropsychological tests are available. In some of these tests, linguistic processing - both oral and written - is an important factor. Language disturbances might serve as a strong indicator for an underlying neurodegenerative disorder like AD. However, the current diagnostic instruments for language assessment mainly focus on product measures, such as text length or number of errors, ignoring the importance of the process that leads to written or spoken language production. In this study, it is our aim to describe and test differences between cognitive and impaired elderly on the basis of a selection of writing process variables (inter- and intrapersonal characteristics). These process variables are mainly related to pause times, because the number, length, and location of pauses have proven to be an important indicator of the cognitive complexity of a process. Method: Participants that were enrolled in our research were chosen on the basis of a number of basic criteria necessary to collect reliable writing process data. Furthermore, we opted to match the thirteen cognitively impaired patients (8 MCI and 5 AD) with thirteen cognitively healthy elderly. At the start of the experiment, participants were each given a number of tests, such as the Mini-Mental State Examination test (MMSE), the Geriatric Depression Scale (GDS), the forward and backward digit span and the Edinburgh Handedness Inventory (EHI). Also, a questionnaire was used to collect socio-demographic information (age, gender, eduction) of the subjects as well as more details on their level of computer literacy. The tests and questionnaire were followed by two typing tasks and two picture description tasks. For the typing tasks participants had to copy (type) characters, words and sentences from a screen, whereas the picture description tasks each consisted of an image they had to describe in a few sentences. Both the typing and the picture description tasks were logged with Inputlog, a keystroke logging tool that allows us to log and time stamp keystroke activity to reconstruct and describe text production processes. The main rationale behind keystroke logging is that writing fluency and flow reveal traces of the underlying cognitive processes. This explains the analytical focus on pause (length, number, distribution, location, etc.) and revision (number, type, operation, embeddedness, location, etc.) characteristics. As in speech, pause times are seen as indexical of cognitive effort. Results. Preliminary analysis already showed some promising results concerning pause times before, within and after words. For all variables, mixed effects models were used that included participants as a random effect and MMSE scores, GDS scores and word categories (such as determiners and nouns) as a fixed effect. For pause times before and after words cognitively impaired patients paused longer than healthy elderly. These variables did not show an interaction effect between the group participants (cognitively impaired or healthy elderly) belonged to and word categories. However, pause times within words did show an interaction effect, which indicates pause times within certain word categories differ significantly between patients and healthy elderly.

Keywords: Alzheimer's disease, keystroke logging, matching, writing process

Procedia PDF Downloads 366

Authors: Emilia Klepczarek

Abstract:

The Basel Committee on Banking Supervision and the OECD found problems with the mechanisms of corporate governance as one of the major causes of destabilization of the financial system and the subprime crisis in the years 2007-2010. In response to these allegations, there were formulated a number of recommendations aimed at improving the quality of supervisory standards in financial institutions. They relate mainly to risk management, remuneration policy, the competence of managers and board members and transparency issues. Nevertheless, a review of the empirical research conducted by the author does not allow for an unambiguous confirmation of the positive impact of the postulated standards on the stability of banking entities. There is, therefore, a presumption of the existence of hidden variables determining the effectiveness of the governance mechanisms. According to the author, this involves concepts arising from behavioral economics and economic anthropology, which allow for an explanation of the effectiveness of corporate governance institutions on the basis of the socio-cultural profile of its members. The proposed corporate governance culture theory indicates that the attributes of the members of the organization and organizational culture can determine the different effectiveness level of the governance processes in similar formal corporate governance structures. The aim of the presentation is, firstly, to draw attention to the vast discrepancies existing within the results of research on the effectiveness of the standards of corporate governance in the banking sector. Secondly, the author proposes an explanation of these differences on the basis of governance theory breaking with common paradigms. The corporate governance culture theory is focused on the identity of the individual and the scope of autonomy offered within his or her institution. The coexistence of these two conditions - the adequate behavioral profile and enough freedom to decide - is a prerequisite for the efficient functioning of the institutions of corporate governance, which can contribute to rehabilitating and strengthening the stability of the financial sector.

Keywords: autonomy, corporate governance, efficiency, governance culture

Procedia PDF Downloads 243

Authors: Mandeep Kaur, Jitendra K. Bera

Abstract:

The search for atom-economical and green synthetic methods for the synthesis of functionalized molecules has attracted much attention. Metal ligand cooperation (MLC) plays a pivotal role in organometallic catalysis to activate C−H, H−H, O−H, N−H and B−H bonds through reversible bond breaking and bond making process. Towards this goal, a bifunctional N─heterocyclic carbene (NHC) based pyridyl-functionalized amide ligand precursor, and corresponding dearomatized iridium complex was synthesized. The NMR and UV/Vis acid titration study have been done to prove the proton response nature of the iridium complex. Further, the dearomatized iridium complex explored as a catalyst on the platform of MLC via dearomatzation/aromatization mode of action towards atom economical α and β─alkylation of ketones and secondary alcohols by using primary alcohols through hydrogen borrowing methodology. The key features of the catalysis are high turnover frequency (TOF) values, low catalyst loading, low base loading and no waste product. The greener syntheses of quinoline, lactone derivatives and selective alkylation of drug molecules like pregnenolone and testosterone were also achieved successfully. Another structurally similar iridium complex was also synthesized with modified ligand precursor where a pendant amide unit was absent. The inactivity of this analogue iridium complex towards catalysis authenticated the participation of proton responsive imido sidearm of the ligand to accelerate the catalytic reaction. The mechanistic investigation through control experiments, NMR and deuterated labeling study, authenticate the borrowing hydrogen strategy.

Keywords: C-C bond formation, hydrogen borrowing, metal ligand cooperation (MLC), n-heterocyclic carbene

Procedia PDF Downloads 181

Authors: Qianqian He, Naian Liu, Xiaodong Xie, Linhe Zhang, Yang Zhang, Weidong Yan

Abstract:

In the wild, the vegetation layer with exceptionally complex fuel composition and heterogeneous spatial distribution strongly affects the rate of fire spread (ROS) and fire intensity. Clarifying the influence of fuel bed structure on fire spread behavior is of great significance to wildland fire management and prediction. The packing ratio is one of the key physical parameters describing the property of the fuel bed. There is a threshold value of the packing ratio for ROS, but little is known about the controlling mechanism. In this study, to address this deficiency, a series of fire spread experiments were performed across a discrete fuel bed composed of some regularly arranged laser-cut cardboards, with constant wind speed and different packing ratios (0.0125-0.0375). The experiment aims to explore the relative importance of the internal and surface heat transfer with packing ratio. The dependence of the measured ROS on the packing ratio was almost consistent with the previous researches. The data of the radiative and total heat fluxes show that the internal heat transfer and surface heat transfer are both enhanced with increasing packing ratio (referred to as ‘Stage 1’). The trend agrees well with the variation of the flame length. The results extracted from the video show that the flame length markedly increases with increasing packing ratio in Stage 1. Combustion intensity is suggested to be increased, which, in turn, enhances the heat radiation. The heat flux data shows that the surface heat transfer appears to be more important than the internal heat transfer (fuel preheating inside the fuel bed) in Stage 1. On the contrary, the internal heat transfer dominates the fuel preheating mechanism when the packing ratio further increases (referred to as ‘Stage 2’) because the surface heat flux keeps almost stable with the packing ratio in Stage 2. As for the heat convection, the flow velocity was measured using Pitot tubes both inside and on the upper surface of the fuel bed during the fire spread. Based on the gas velocity distribution ahead of the flame front, it is found that the airflow inside the fuel bed is restricted in Stage 2, which can reduce the internal heat convection in theory. However, the analysis indicates not the influence of inside flow on convection and combustion, but the decreased internal radiation of per unit fuel is responsible for the decrease of ROS.

Keywords: discrete fuel bed, fire spread, packing ratio, wildfire

Procedia PDF Downloads 142

Authors: Numfon Rakkhumkaew, Takeru Kawasaki, Makoto Fujie, Takashi Yamada

Abstract:

Chlorella viruses or chloroviruses contain a gene that encodes a function for chitin synthesis, which is expressed early in viral infection to produce chitin polysaccharide, a polymer of β-1, 4-linked GlcNAc, on the outside of Chlorella cell wall. Interestingly, chlorovirus system is an eco-friendly system which converses CO2 and solar energy from the environment into useful materials. However, infected Chlorella cells are lysed at the final stage of viral infection, and this phenomenon is caused the breaking down of polysaccharide. To postpone the lysing period and prolong the synthesis of chitin polysaccharide on cells, the slow growing virus incorporated with aphidicolin treatment, an inhibitor of DNA synthesis, was investigated. In this study, a total of 25 virus isolates from water samples in Japan region were analyzed for CHS (the gene for CH synthase) gene by PCR (polymerase chain reaction). The accumulation and appearance of chitin polysaccharide on infected cells were detected by biotinylated chitin-binding proteins WGA (wheat germ agglutinin)-biotin for chitin in conjunction with avidin-Cy 2 or Cy 3 and investigated by fluorescence microscopy, observed as green or yellow fluorescence over the cell surface. Among all chlorovirus isolates, cells infected with CNF1 revealed the accumulation of chitin over the cell surface within 30 min p.i. and continued to accumulate on cells until 4 h p.i. before cell lyses which was 1.6 times longer accumulation period than cells infected with CVK2 (prototype virus). Furthermore, addition of aphidicolin could extend the chitin accumulation on cells infected with CNF1 until 8 h p.i. before cell lyses. Whereas, CVK2-infected cells treated with aphidicolin could prolong the chitin synthesis only for 6 h p.i. before cell lyses. Therefore, chitin synthesis by Chlorella-virus system could be prolonged by using slow-growing viral isolates and with aphidicolin.

Keywords: chitin, chlorovirus, Chlorella virus, aphidicolin

Procedia PDF Downloads 213

Authors: Taiwo Olusoji Lawrence, Peace Mawo Aaron

Abstract:

Seismic analysis of bedforms has proven to be one of the best ways to study deepwater sedimentary features. Canyons are known to be sediment transportation conduit. Sediment wave are large-scale depositional bedforms in various parts of the world's oceans formed predominantly by suspended load transport. These undulating objects usually have tens of meters to a few kilometers in wavelength and a height of several meters. Cyclic steps have long long-wave upstream-migrating bedforms confined by internal hydraulic jumps. They usually occur in regions with high gradients and slope breaks. Cyclic steps and migrating sediment waves are the most common bedform on the seafloor. Cyclic steps and related sediment wave bedforms are significant to the morpho-dynamic evolution of deep-water depositional systems architectural elements, especially those located along tectonically active margins with high gradients and slope breaks that can promote internal hydraulic jumps in turbidity currents. This report examined sedimentary activities and sediment transportation in submarine canyons and provided distinctive insight into factors that created a complex seabed canyon system in the Ceara Fortaleza basin Brazilian Equatorial Margin (BEM). The growing importance of cyclic steps made it imperative to understand the parameters leading to their formation, migration, and architecture as well as their controls on sediment transport in canyon thalweg. We extracted the parameters of the observed bedforms and evaluated the aspect ratio and asymmetricity. We developed a relationship between the hydraulic jump magnitude, depth of the hydraulic fall and the length of the cyclic step therein. It was understood that an increase in the height of the cyclic step increases the magnitude of the hydraulic jump and thereby increases the rate of deposition on the preceding stoss side. An increase in the length of the cyclic steps reduces the magnitude of the hydraulic jump and reduces the rate of deposition at the stoss side. Therefore, flat stoss side was noticed at most preceding cyclic step and sediment wave.

Keywords: Ceara Fortaleza, submarine canyons, cyclic steps, sediment wave

Procedia PDF Downloads 114

Authors: Bahar Hazal Yalçınkaya, Bayram Yılmaz, Mustafa Özilgen

Abstract:

Brain information transmission in the neuronal network occurs in the form of electrical signals. Neural work transmits information between the neurons or neurons and target cells by moving charged particles in a voltage field; a fraction of the energy utilized in this process is dissipated via entropy generation. Exergy loss and entropy generation models demonstrate the inefficiencies of the communication along the dendritic trees. In this study, neurons of 4 different animals were analyzed with one dimensional cable model with N=6 identical dendritic trees and M=3 order of symmetrical branching. Each branch symmetrically bifurcates in accordance with the 3/2 power law in an infinitely long cylinder with the usual core conductor assumptions, where membrane potential is conserved in the core conductor at all branching points. In the model, exergy loss and entropy generation rates are calculated for each branch of equivalent cylinders of electrotonic length (L) ranging from 0.1 to 1.5 for four different dendritic branches, input branch (BI), and sister branch (BS) and two cousin branches (BC-1 & BC-2). Thermodynamic analysis with the data coming from two different cat motoneuron studies show that in both experiments nearly the same amount of exergy is lost while generating nearly the same amount of entropy. Guinea pig vagal motoneuron loses twofold more exergy compared to the cat models and the squid exergy loss and entropy generation were nearly tenfold compared to the guinea pig vagal motoneuron model. Thermodynamic analysis show that the dissipated energy in the dendritic tress is directly proportional with the electrotonic length, exergy loss and entropy generation. Entropy generation and exergy loss show variability not only between the vertebrate and invertebrates but also within the same class. Concurrently, single action potential Na⁺ ion load, metabolic energy utilization and its thermodynamic aspect contributed for squid giant axon and mammalian motoneuron model. Energy demand is supplied to the neurons in the form of Adenosine triphosphate (ATP). Exergy destruction and entropy generation upon ATP hydrolysis are calculated. ATP utilization, exergy destruction and entropy generation showed differences in each model depending on the variations in the ion transport along the channels.

Keywords: ATP utilization, entropy generation, exergy loss, neuronal information transmittance

Procedia PDF Downloads 393

Authors: S. Begum, T. Biswas, M. A. Islam

Abstract:

The present research investigates the distribution and contamination of heavy metals in core sediments collected from three locations of the Sundarbans mangrove forest. In this research, quality of the analysis is evaluated by analyzing certified reference materials IAEA-SL-1 (lake sediment), IAEA-Soil-7, and NIST-1633b (coal fly ash). Total concentrations of 28 heavy metals (Na, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, Ga, As, Sb, Cs, La, Ce, Sm, Eu, Tb, Dy, Ho, Yb, Hf, Ta, Th, and U) have determined in core sediments of the Sundarbans mangrove by neutron activation analysis (NAA) technique. When compared with upper continental crustal (UCC) values, it is observed that mean concentrations of K, Ti, Zn, Cs, La, Ce, Sm, Hf, and Th show elevated values in the research area is high. In this research, the assessments of metal contamination levels using different environmental contamination indices (EF, Igeo, CF) indicate that Ti, Sb, Cs, REEs, and Th have minor enrichment of the sediments of the Sundarbans. The modified degree of contamination (mCd) of studied samples of the Sundarbans ecosystem show low contamination. The pollution load index (PLI) values for the cores suggested that sampling points are moderately polluted. The possible sources of the deterioration of the sediment quality can be attributed to the different chemical carrying cargo accidents, port activities, ship breaking, agricultural and aquaculture run-off of the area. Pearson correlation matrix (PCM) established relationships among elements. The PCM indicates that most of the metal's distributions have been controlled by the same factors such as Fe-oxy-hydroxides and clay minerals, and also they have a similar origin. The poor correlations of Ca with most of the elements in the sediment cores indicate that calcium carbonate has a less significant role in this mangrove sediment. Finally, the data from this research will be used as a benchmark for future research and help to quantify levels of metal pollutions, as well as to manage future ecological risks of the vulnerable mangrove ecosystem, the Sundarbans.

Keywords: contamination, core sediment, trace element, sundarbans, vulnerable

Procedia PDF Downloads 122

Authors: Anurag Sharma, Rahul Malhotra, Love Kumar, Harjit Pal Singh

Abstract:

This paper demonstrates OCDM-ROF based hybrid architecture where data/voice communication is enabled via a permutation of Optical Code Division Multiplexing (OCDM) and Radio-over-Fiber (RoF) techniques under various diverse conditions. OCDM-RoF hybrid network of 16 users with DPSK modulation format has been designed and performance of proposed network is analyzed for 100, 150, and 200 km fiber span length under the influence of linear and nonlinear effect. It has been reported that Polarization Mode Dispersion (PMD) has the least effect while other nonlinearity affects the performance of proposed network.

Keywords: OCDM, RoF, DPSK, PMD, eye diagram, BER, Q factor

Procedia PDF Downloads 638

Authors: Seyed Abolhassan Naeini, Hamed Yekehdehghan

Abstract:

Shallow foundations cannot be used when the bedding soil is soft. A suitable method for constructing foundations on soft soil is to employ pile groups to transfer the load to the bottom layers. The present research used results from tests carried out in northern Iran (Langarud) and the FLAC3D software to model a pile group for investigating the effects of various parameters on pile cap settlement under static and seismic conditions. According to the results, changes in the strength parameters of the soil, groundwater level, and the length of and distance between the piles affect settlement differently.

Keywords: FLACD 3D software, pile group, settlement, soil

Procedia PDF Downloads 128

Authors: Yodai Ashikubo, Toshiaki Suzuki, Satoshi Kouya, Mitsuya Motohashi

Abstract:

Functional microstructures such as wires, fins, needles, and rolls are currently being applied to variety of high-performance devices. Under these conditions, a roll structure (silicon micro-nanoroll) was formed on the surface of the silicon substrate via fine bubbles during anodization using an extremely diluted hydrofluoric acid (HF + H₂O). The as-formed roll had a microscale length and width of approximately 1 µm. The number of rolls was 3-10 times and the thickness of the film forming the rolls was about 10 nm. Thus, it is promising for applications as a distinct device material. These rolls functioned as capsules and/or pipelines. To date, number of rolls and roll length have been controlled by anodization conditions. In general, controlling the position and roll winding state is required for device applications. However, it has not been discussed. Grooves formed on silicon surface before anodization might be useful control the bubbles. In this study, we investigated the effect of the grooves on the position and shape of the roll. The surfaces of the silicon wafers were anodized. The starting material was p-type (100) single-crystalline silicon wafers. The resistivity of the wafer is 5-20 ∙ cm. Grooves were formed on the surface of the substrate before anodization using sandpaper and diamond pen. The average width and depth of the grooves were approximately 1 µm and 0.1 µm, respectively. The HF concentration {HF/ (HF + C₂H5OH + H₂O)} was 0.001 % by volume. The C2H5OH concentration {C₂H5OH/ (HF + C₂H5OH + H₂O)} was 70 %. A vertical single-tank cell and Pt cathode were used for anodization. The silicon roll was observed by field-emission scanning electron microscopy (FE-SEM; JSM-7100, JEOL). The atomic bonding state of the rolls was evaluated using X-ray photoelectron spectroscopy (XPS; ESCA-3400, Shimadzu). For straight groove, the rolls were formed along the groove. This indicates that the orientation of the rolls can be controlled by the grooves. For lattice-like groove, the rolls formed inside the lattice and along the long sides. In other words, the aspect ratio of the lattice is very important for the roll formation. In addition, many rolls were formed and winding states were not uniform when the lattice size is too large. On the other hand, no rolls were formed for small lattice. These results indicate that there is the optimal size of lattice for roll formation. In the future, we are planning on formation of rolls using groove formed by lithography technique instead of sandpaper and the pen. Furthermore, the rolls included nanoparticles will be formed for nanodevices.

Keywords: silicon roll, anodization, fine bubble, microstructure

Procedia PDF Downloads 18

Authors: Porag Jyoti Ligira, Gargi Khanna

Abstract:

The paper presents a simulation study of the electrical characteristic of Bulk Planar Junctionless Transistor (BPJLT) using spacer. The BPJLT is a transistor without any PN junctions in the vertical direction. It is a gate controlled variable resistor. The characteristics of BPJLT are analyzed by varying the oxide material under the gate. It can be shown from the simulation that an ideal subthreshold slope of ~60 mV/decade can be achieved by using highk dielectric. The effects of variation of spacer length and material on the electrical characteristic of BPJLT are also investigated in the paper. The ION / IOFF ratio improvement is of the order of 107 and the OFF current reduction of 10-4 is obtained by using gate dielectric of HfO2 instead of SiO2.

Keywords: spacer, BPJLT, high-k, double gate

Procedia PDF Downloads 429

Authors: I. Ioannou, I. M. Gitman

Abstract:

This study focused on the contribution of micro-mechanical parameters on the macro-mechanical response of short fiber composites, namely polypropylene matrix reinforced by glass fibers. In the framework of this paper, an attention has been given to the glass fibers length, as micromechanical parameter influences the overall macroscopic material’s behavior. Three dimensional numerical models were developed and analyzed through the concept of a Representative Volume Element (RVE). Results of the RVE-based approach were compared with analytical Halpin-Tsai’s model.

Keywords: effective properties, homogenization, representative volume element, short fiber reinforced composites

Procedia PDF Downloads 268

Authors: Fangyuan Shao, Wei Liu, Deli Gao

Abstract:

With the increasing speed of oil and gas exploration, development and production at home and abroad, the demand for drilling speed up technology is becoming more and more critical to reduce the development cost. Highly efficient and personalized PDC bit is important equipment in the bottom hole assembly (BHA). Therefore, improving the rock-breaking efficiency of PDC bits will help reduce drilling time and drilling cost. Advances in PDC bit technology have resulted in a leapfrogging improvement in the rate of penetration (ROP) of PDC bits over roller cone bits in soft to medium-hard formations. Recently, with the development of PDC technology, the diameter of the PDC tooth can be further expanded. The maximum diameter of the PDC cutter used in this paper is 22 mm. According to the theoretical calculation, under the same depth of cut (DOC), the 22mm-PDC cutter increases the exposure of the cutter, and the increase of PDC cutter diameter helps to increase the cutting area of the PDC cutter. In order to evaluate the cutting performance of the 22 mm-PDC cutter and the existing commonly used cutters, the 16 mm, 19 mm and 22 mm PDC cutter was selected put on a vertical turret lathe (VTL) in the laboratory for cutting tests under different DOCs. The DOCs were 0.5mm, 1.0 mm, 1.5 mm and 2.0 mm, 2.5 mm and 3 mm, respectively. The rock sample used in the experiment was limestone. Results of laboratory tests have shown the new 22 mm-PDC cutter technology greatly improved cutting efficiency. On the one hand, as the DOC increases, the mechanical specific energy (MSE) of all cutters decreases, which means that the cutting efficiency increases. On the other hand, under the same DOC condition, the larger the cutter diameter is, the larger the working area of the cutter is, which leads to higher the cutting efficiency. In view of the high performance of the 22 mm-PDC cutters, which was applied to carry out full-scale bit field experiments. The result shows that the bit with 22mm-PDC cutters achieves a breakthrough improvement of ROP than that with conventional 16mm and 19mm cutters in offset well drilling.

Keywords: polycrystalline diamond compact, 22 mm-PDC cutters, cutting efficiency, mechanical specific energy

Procedia PDF Downloads 204

Authors: V. Gareyan, Zh. Gevorkian

Abstract:

We study oblique incident light absorption in opaque media with rough surfaces. An analytical approach with modified boundary conditions taking into account the surface roughness in metallic or dielectric films has been discussed. Our approach reveals interference-linked terms that modify the absorption dependence on different characteristics. We have discussed the limits of our approach that hold valid from the visible to the microwave region. Polarization and angular dependences of roughness-induced absorption are revealed. The existence of an incident angle or a wavelength for which the absorptance of a rough surface becomes equal to that of a flat surface is predicted. Based on this phenomenon, a method of determining roughness correlation length is suggested.

Keywords: light, absorption, surface, roughness

Procedia PDF Downloads 54

Authors: Fahad Alsharari, Mohd Salmi Md. Noorani

Abstract:

A Motzkin shift is a mathematical model for constraints on genetic sequences. In terms of the theory of symbolic dynamics, the Motzkin shift is nonsofic, and therefore, we cannot use the Perron-Frobenius theory to calculate its topological entropy. The Motzkin shift M(M,N) which comes from language theory, is defined to be the shift system over an alphabet A that consists of N negative symbols, N positive symbols and M neutral symbols. For an x in the full shift AZ, x is in M(M,N) if and only if every finite block appearing in x has a non-zero reduced form. Therefore, the constraint for x cannot be bounded in length. K. Inoue has shown that the entropy of the Motzkin shift M(M,N) is log(M + N + 1). In this paper, we find a new method of calculating the topological entropy of the Motzkin shift M(M,N) without any measure theoretical discussion.

Keywords: entropy, Motzkin shift, mathematical model, theory

Procedia PDF Downloads 476

Authors: Rima Zakzouk, Yasushi Shimada, Yuan Zhou, Yasunori Sumi, Junji Tagami

Abstract:

Background and Purpose: Swept source optical coherence tomography (OCT) is an interferometric imaging technique that has been recently used in cariology. In spite of progress made in adhesive dentistry, the composite restoration has been failing due to secondary caries which occur due to environmental factors in oral cavities. Therefore, a precise assessment to effective marginal sealing of restoration is highly required. The aim of this study was evaluating gap formation at composite/cavity walls interface with or without phosphoric acid etching using SS-OCT. Materials and Methods: Round tapered cavities (2×2 mm) were prepared in three locations, mid-coronal, cervical, and root of bovine incisors teeth in two groups (SE and PA Groups). While self-etching adhesive (Clearfil SE Bond) was applied for the both groups, Group PA had been already pretreated with phosphoric acid etching (K-Etchant gel). Subsequently, both groups were restored by Estelite Flow Quick Flowable Composite Resin. Following 5000 thermal cycles, three cross-sectionals were obtained from each cavity using OCT at 1310-nm wavelength at 0°, 60°, 120° degrees. Scanning was repeated after two months to monitor the gap progress. Then the average percentage of gap length was calculated using image analysis software, and the difference of mean between both groups was statistically analyzed by t-test. Subsequently, the results were confirmed by sectioning and observing representative specimens under Confocal Laser Scanning Microscope (CLSM). Results: The results showed that pretreatment with phosphoric acid etching, Group PA, led to significantly bigger gaps in mid-coronal and cervical compared to SE group, while in the root cavity no significant difference was observed between both groups. On the other hand, the gaps formed in root’s cavities were significantly bigger than those in mid-coronal and cervical within the same group. This study investigated the effect of phosphoric acid on gap length progress on the composite restorations. In conclusions, phosphoric acid etching treatment did not reduce the gap formation even in different regions of the tooth. Significance: The cervical region of tooth was more exposing to gap formation than mid-coronal region, especially when we added pre-etching treatment.

Keywords: image analysis, optical coherence tomography, phosphoric acid etching, self-etch adhesives

Procedia PDF Downloads 221

Authors: Amin Saeidi

Abstract:

Using a representation-theoretic approach and considering G to be a finite primitive permutation group of degree n, our aim is to determine linear codes of length n that admit G as a permutation automorphism group. We can show that in some cases, every binary linear code admitting G as a permutation automorphism group is a submodule of a permutation module defined by a primitive action of G. As an illustration of the method, we consider the sporadic simple group M₁₁ and the unitary group U(3,3). We also construct some point- and block-primitive 1-designs from the supports of some codewords of the codes in the discussion.

Keywords: linear code, permutation representation, support design, simple group

Procedia PDF Downloads 77