Search results for: supersonic cross flow

Authors: Anu S. Krishna

Abstract:

The paper tries to analyse the UN involvement/intervention in the case of intra-state armed conflict of El Salvador and Nepal comparatively. The peace mission in El Salvador is considered to be the most successful missions of UN ever since it started involving in the peace-building activities. Meanwhile, in the armed conflict of South Asian country, Nepal, the result seemed to be disappointing in comparison with its counterpart. The study on this paper takes three variables as the success or failure of international mediation, i.e., a) signing of the peace agreement, b) disarmament/demobilization and c) constitutional mechanism. A significant amount of scholarship looks at the case of ONUSAL (United Nations Mission in El Salvador). Meanwhile, the armed conflict of Nepal and the role of UNMIN (United Nations Mediation in Nepal) are under researched so far. The paper thus tries to throw light on these cross-regional contexts that share certain similarities and dissimilarities in the nature of conflict. In addition, the international third-party involvement and their way of approaching both the cases differ, which again affected the mediation outcome. The paper tries to argue that, since the approach of the UN led international mediation in theses peace missions were contextual and varied from case to case, thus, finally affected the mediation outcome too.

Keywords: Nepal, UNMIN, El Salvador, ONUSAL, international mediation, armed conflict

Procedia PDF Downloads 389

Authors: Ibrahim Bashayreh Al-Bashtawy Mohammed, Al-Azzam Manar Ahmad Rawashda, Abdul-Monim Batiha Mohammad Sulaiman

Abstract:

Background: Workplace violence against emergency department staff (EDS) is considered one of the most common and widespread phenomena of violence. Purpose: The purpose of this research is to determine the incidence rates of workplace violence and the predicting factors of violent behaviors among emergency departments’ staff in Jordanian hospitals. Methods: A cross-sectional study was used to investigate workplace violence towards a convenience sample of 355 emergency staff departments from 8 governmental and 4 private Jordanian hospitals. Data were collected by a self-administered questionnaire that was developed for the purpose of this study. Results: 72% of workers in emergency departments within Jordanian hospitals are exposed to violent acts, and that patients and their relatives are the main source of workplace violence. The contributing factors as reported by the participants were related to overcrowding, lack of resources, staff shortages, and the absence of effective antiviolence policies. Conclusions/implications for Practice: Policies and legislation regarding violence should be instituted and developed, and emergency department staff should be given training on how to deal with violent incidents, as well as on violence-management policies.

Keywords: Jordan, emergency staff department, workplace violence, community health

Procedia PDF Downloads 325

Authors: Mindaugas Zavalis

Abstract:

Analysis of experimental tests data of bending one-way reinforced concrete slabs from various articles of science revealed that voided slabs with a grid of hollow plastic inserts inside have smaller mechani-cal and physical parameters compared to continuous cross-section slabs (solid slabs). The negative influence of a reinforced concrete slab is impacted by hollow plastic inserts, which make a grid of voids in the middle of the cross-sectional area of the reinforced concrete slab. A formed grid of voids reduces the slab’s stiffness, which influences the slab’s parameters of serviceability, like deflection and cracking. Prima-ry investigation of data established during experiments illustrates that cracks occur faster in the tensile surface of the voided slab under bend-ing compared to bending solid slab. It means that the crack bending moment force for the voided slab is smaller than the solid slab and the reduction can variate in the range of 14 – 40 %. Reduce of resistance to cracking can be controlled by changing a lot of factors: the shape of the plastic hallow insert, plastic insert height, steps between plastic in-serts, usage of prestressed reinforcement, the diameter of reinforcement bar, slab effective depth, the bottom cover thickness of concrete, effec-tive cross-section of the concrete area about reinforcement and etc. Mentioned parameters are used to evaluate crack width and step of cracking, but existing analytical calculation methods for cracking eval-uation of voided slab with plastic inserts are not so exact and the re-sults of cracking evaluation in this paper are higher than the results of analyzed experiments. Therefore, it was made analytically calculations according to experimental bending tests of voided reinforced concrete slabs with hollow plastic inserts to find and propose corrections for the evaluation of cracking for reinforced concrete voided slabs with hollow plastic inserts.

Keywords: voided slab, cracking, hallow plastic insert, bending, one-way reinforced concrete, serviceability

Procedia PDF Downloads 64

Authors: Ayman M. El-Zahaby, Ahmed S. El-Gendy

Abstract:

Aeration for wastewater is essential for the proper operation of aerobic treatment units where the wastewater normally has zero dissolved oxygen. This is due to the need of oxygen by the aerobic microorganisms to grow and survive. Typical aeration units for wastewater treatment require electric energy for their operation such as mechanical aerators or diffused aerators. The passive units are units that operate without the need of electric energy such as cascade aerators, spray aerators and tray aerators. In contrary to the cascade aerators and spray aerators, tray aerators require much smaller area foot print for their installation as the treatment stages are arranged vertically. To the extent of the authors knowledge, the design of tray aerators for the aeration purpose has not been presented in the literature. The current research concerns with an analytical study for the design of tray aerators for the purpose of increasing the dissolved oxygen in wastewater treatment systems, including an investigation on different design parameters and their impact on the aeration efficiency. The studied aerator shall act as an intermediate stage between an anaerobic primary treatment unit and an aerobic treatment unit for small scale treatment systems. Different free falling flow regimes were investigated, and the thresholds for transition between regimes were obtained from the literature. The study focused on the jetting flow regime between trays. Starting from the two film theory, an equation that relates the dissolved oxygen concentration effluent from the system was derived as a function of the flow rate, number of trays, tray area, spacing between trays, number and diameter of holes and the water temperature. A MATLab ® model was developed for the derived equation. The expected aeration efficiency under different tray configurations and operating conditions were illustrated through running the model with varying the design parameters. The impact of each parameter was illustrated. The overall system efficiency was found to increase by decreasing the hole diameter. On the other side, increasing the number of trays, tray area, flow rate per hole or tray spacing had positive effect on the system efficiency.

Keywords: aeration, analytical, passive, wastewater

Procedia PDF Downloads 205

Authors: Mohamad Muqtada Ali Khan, Nor Ashikin Shaari, Donny Adriansyah bin Nazaruddin, Hafzan Eva Bt Mansoor

Abstract:

Floods play a key role in landform evolution of an area. This process is likely to alter the topography of the earth’s surface. The present study area, Kota Bharu is very prone to floods extends from upstream of Kelantan River near Kemubu to the downstream area near Kuala Besar. These flood events which occur every year in the study area exhibit a strong bearing on river morphological set-up. In the present study, three satellite imageries of different time periods have been used to manifest the post-flood landform changes. The pre-processing of the images such as subset, geometric corrections and atmospheric corrections were carried-out using ENVI 4.5 followed by the analysis processes. Twenty sets of cross sections were plotted using software Erdas 9.2, ERDAS and ArcGis 10 for the all three images. The results show a significant change in the length of the cross section which suggest that the geomorphological processes play a key role in carving and shaping the river banks during the floods.

Keywords: flood induced, geomorphic imprints, Kelantan river, Malaysia

Procedia PDF Downloads 542

Authors: Abdul-Razak Inusah

Abstract:

The study is a cross-sectional investigation of issues in Dagbanli Phonology, a Mabia language spoken in the Northern Region of Ghana. The issues investigated and assessed for the purpose of Dagbanli phonology are the status of the velar fricatives [x, ɣ] and the flap [ɾ] across Dagbanli dialects. The ethnographic approach is employed to solicit the primary data from bucolic Dagbanli speech communities. The descriptive method is engaged for the analysis of the primary data available. The investigation reveals that the dialects have the velar fricatives [x, ɣ] confined to specific segmental contexts with a particular inventory stricture. The flap[ɾ] is noticed to occur mostly in intervocalic but entirely missing in Dagbanli indigenous words in word-initial. The velar fricatives [x, ɣ] and the flap[ɾ] are observed to be non-contrastive and only suffice as dialectal allophones in the language. The paper shows evidence of coalesce of non-coronal labial /m/ and coronal fricative /s/ to produce dorsal fricative [x] in intervocalic and coalesce of stem final stop /ɡ/ and suffix onset fricative /s/ to yield the dorsal fricative [x], a finding which shows the status of the segment [x] in Dagbanli phonology. The paper concludes that the segments [x], [ɣ] and [ɾ] are positional variants of /ɡ+s/ or /m+s/, /ɡ/ and /d/.

Keywords: Dagbani, phonology, dialect, segment, fricatives, coalesce

Procedia PDF Downloads 46

Authors: Mohammad Ali Badri, Pouya Molana, Amin Rezvanpour

Abstract:

In this paper, planning catamaran and mono-hull vessels resistance and trim in calm waters were considered. Hydrodynamic analysis of fast mono-hull planning vessel was also investigated. In order to hull form geometry optimization, numerical methods of different parameters were used for this type of vessels. Hull material was selected in carbon fiber composite. Exact architectural aspects were specified and stability calculations were performed as well. Hydrodynamic calculations to extract the resistance force using semi-analytical methods and numerical modeling were carried out. Free surface numerical analysis of vessel in designed draft using finite volume method and double phase were evaluated and verified by experimental tests.

Keywords: fast vessel, hydrostatic and hydrodynamic optimization, free surface flow, computational fluid dynamics

Procedia PDF Downloads 512

Authors: Hayyan I Al Taweil

Abstract:

Background: The most common of bacterium in kitchen sponges and cutting surfaces which can play a task within the cross-contamination of foods, fomites and hands by foodborne pathogens. Aims and Objectives: This study investigated the incidence of bacterium in kitchen Sponge, and cutting surfaces. Material and methods: a complete of twenty four kitchen Sponges were collected from home kitchens and therefore the numbers of mesotrophic microorganism, coliform microorganism, E. coli, Salmonella, genus {pseudomonas|bacteria genus} and staphylococci in every kitchen Sponges were determined. Microbiological tests of all sponges for total mesophilic aerobic microorganism, S. aureus, Pseudomonas, Salmonella spp., and E. coli were performed on days 3, 7, and 14 by sampling. The sponges involved in daily use in kitchens countenosely with the dishwasher detergent a minimum of doubly daily Results: Results from the overall mesophilic aerobic microorganism, indicate a major increase within the variety of log CFU/ml. the amount of E. coli was reduced, Salmonella spp. was stabled, S. aureus was enhanced from the sponges throughout fourteen days. Genus Pseudomonas was enhanced and was the dominant micro flora within the sponges throughout fourteen days.

Keywords: Kitchen Sponges, Microbiological Contamination, Disinfection; cutting surface; , Cross-Contamination

Procedia PDF Downloads 138

Authors: Alaa A. Almarzuki, Nora A. Farraj, Aisha M. Alshiky, Omar A. Batarfi

Abstract:

The number of internet users is dramatically increased every year. Most of these users are exposed to the dangers of attackers in one way or another. The reason for this lies in the presence of many weaknesses that are not known for native users. In addition, the lack of user awareness is considered as the main reason for falling into the attackers’ snares. Cross Site Request Forgery (CSRF) has placed in the list of the most dangerous threats to security in OWASP Top Ten for 2013. CSRF is an attack that forces the user’s browser to send or perform unwanted request or action without user awareness by exploiting a valid session between the browser and the server. When CSRF attack successes, it leads to many bad consequences. An attacker may reach private and personal information and modify it. This paper aims to detect and prevent a specific type of CSRF, called reflected CSRF. In a reflected CSRF, a malicious code could be injected by the attackers. This paper explores how CSRF Detection Extension prevents the reflected CSRF by checking browser specific information. Our evaluation shows that the proposed solution succeeds in preventing this type of attack.

Keywords: CSRF, CSRF detection extension, attackers, attacks

Procedia PDF Downloads 411

Authors: Beruk Berhanu Desalegn, Tona Diddana, Alemneh Daba

Abstract:

Objective: The aim of this study was to assess the magnitude and determinants of overnutrition among school going adolescents from Dale District of Ethiopia. Methods: An institution-based cross-sectional study was done between November and December 2020. A total of 333 school going adolescents aged 10-19 years were participated. Socio-demographic, lifestyle, physical activity level, an estimated individual dietary energy intake; and height and weight data were collected. Body Mass Index for age (BAZ) was computed. Results: The magnitude of over-nutrition was 7.2% (10.8% in urban vs. 3.6% in rural). Lack of adequate playing area (AOR=2.53, 95% CI:1.02, 6.26), being an urban resident (AOR=3.05, 95% CI:1.12, 8.29), having more energy intake than expenditure (AOR=9.47, 95% CI:1.58, 56.80), ever consumed fast foods a month before the survey (AOR=2.60, 95% CI:1.93, 6.83), having moderate physical activity (PA) (AOR =9.28, 95% CI: 6.70, 71.63), low PA (AOR=7.95, 95% CI:1.12, 56.72), and having snack between meals (AOR=3.32, 95% CI:1.15, 9.58) were positively associated with over-nutrition. Conclusion: The magnitude of over-nutrition among school going adolescents was lower compared to previous reports in Ethiopia. Sedentary lifestyles, excess calorie intake, not having adequate playing areas in the schools, and having snacks between meals were statistically predicted determinants for over-nutrition in the study area.

Keywords: adolescent, over-nutrition, school, Ethiopia

Procedia PDF Downloads 64

Authors: Yasin Kutuk, Bengi Yanik Ilhan

Abstract:

Previous studies investigate the wage differentiations among regions in Turkey between couples who work in the same industry and those who work in different industries by using the models that is appropriate for cross sectional data. However, since there is no available panel data for this investigation in Turkey, pseudo panels using repeated cross-section data sets of the Household Labor Force Surveys 2004-2014 are employed in order to open a new way to examine wage differentiation patterns. For this purpose, household heads are separated into groups with respect to their household composition. These groups’ membership is assumed to be fixed over time such as age groups, education, gender, and NUTS1 (12 regions) Level. The average behavior of them can be tracked overtime same as in the panel data. Estimates using the pseudo panel data would be consistent with the estimates using genuine panel data on individuals if samples are representative of the population which has fixed composition, characteristics. With controlling the socioeconomic factors, wage differentiation of household income is affected by social, cultural and economic changes after global economic crisis emerged in US. It is also revealed whether wage differentiation is changing among the birth cohorts.

Keywords: wage income, same industry, pseudo panel, panel data econometrics

Procedia PDF Downloads 394

Authors: Maryam Kamali Nezhad

Abstract:

The Robert-Bourassa development (LG-2), the first to be built on the Grande Rivière, comprises two sets of eight turbines- generator units each, the East and West powerhouses. Each powerhouse has two tailrace tunnels with an average length of about 1178 m. The LG-2A powerhouse houses 6 turbine-generator units. The water is discharged through two tailrace tunnels with a length of about 1330 m. The objective of this work, at RB (LG-2), is; 1) to establish a new maximum transient level in the surge chamber, 2) to define the new maximum equipment flow rate for the future turbine-generator units, 3) to ensure safe access to various intervention locations in the surge chamber. The transient levels under normal operating conditions at the RB plant were determined in 2001 by the Hydraulics Unit of HQE using the "Chamber" software. It is a one-dimensional mass oscillation calculation software; it is used to determine the variation of the water level in the equilibrium chamber located downstream of a power plant during the load shedding of the power plant units; it can also be used in the case of an equilibrium stack upstream of a power plant. The RB (LG-2) plant study is based on the theoretical nominal geometry of the chamber and the tailrace tunnels and the flow-level relationship at the outlet of the galleries established during design. The software is used in such a way that the results have an acceptable margin of safety, especially with respect to the maximum transient level (e.g., resumption of flow at an inopportune time), to take into account the turbulent and three-dimensional aspects of the actual flow in the chamber. Note that the transient levels depend on the water levels in the river and in the steady-state equilibrium chambers. These data are established in the HQP CRP database and updated from time to time. The maximum transient levels in the RB-East and RB-West powerhouses surge chamber were revised based on the latest update (set 4) of in-river rating curves and steady-state surge chamber water levels. The results of the revision were also used to update the technical advice on the operating conditions for the aforementioned surge chamber access while considering revisions to the calculated water levels.

Keywords: generating station, surge chamber, maximum transient level, hydroelectric power station, turbine-generator, reservoir

Procedia PDF Downloads 80

Authors: Anuar Ishak

Abstract:

The characteristics of stagnation point flow of a nanofluid towards a stretching/shrinking sheet are investigated. The governing partial differential equations are transformed into a set of ordinary differential equations, which are then solved numerically using MATLAB routine boundary value problem solver bvp4c. The numerical results show that dual (upper and lower branch) solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. It is found that the skin friction decreases when the sheet is stretched, but increases when the suction effect is increased. It is also found that increasing the thermophoresis parameter reduces the heat transfer rate at the surface, while increasing the Brownian motion parameter increases the mass transfer rate at the surface.

Keywords: dual solutions, heat transfer, forced convection, nanofluid, stability analysis

Procedia PDF Downloads 412

Authors: Casta Guillaume, Robert Jagers, Deborah Rivas-Drake

Abstract:

Civically engaged youth are critical to maintaining and/or improving the functioning of local, national and global communities and their institutions. The present study investigated how school climate and academic beliefs (academic self-efficacy and school belonging) may inform emergent civic behaviors (emergent citizenship) among self-identified middle school youth of color (African American, Multiracial or Mixed, Latino, Asian American or Pacific Islander, Native American, and other). Study aims: 1) Understand whether and how school climate is associated with civic engagement behaviors, directly and indirectly, by fostering a positive sense of connection to the school and/or engendering feelings of self-efficacy in the academic domain. Accordingly, we examined 2) The association of youths’ sense of school connection and academic self-efficacy with their personally responsible and participatory civic behaviors in school and community contexts—both concurrently and longitudinally. Data from two subsamples of a larger study of social/emotional development among middle school students were used for longitudinal and cross sectional analysis. The cross-sectional sample included 324 6th-8th grade students, of which 43% identified as African American, 20% identified as Multiracial or Mixed, 18% identified as Latino, 12% identified as Asian American or Pacific Islander, 6% identified as Other, and 1% identified as Native American. The age of the sample ranged from 11 – 15 (M = 12.33, SD = .97). For the longitudinal test of our mediation model, we drew on data from the 6th and 7th grade cohorts only (n =232); the ethnic and racial diversity of this longitudinal subsample was virtually identical to that of the cross-sectional sample. For both the cross-sectional and longitudinal analyses, full information maximum likelihood was used to deal with missing data. Fit indices were inspected to determine if they met the recommended thresholds of RMSEA below .05 and CFI and TLI values of at least .90. To determine if particular mediation pathways were significant, the bias-corrected bootstrap confidence intervals for each indirect pathway were inspected. Fit indices for the latent variable mediation model using the cross-sectional data suggest that the hypothesized model fit the observed data well (CFI = .93; TLI =. 92; RMSEA = .05, 90% CI = [.04, .06]). In the model, students’ perceptions of school climate were significantly and positively associated with greater feelings of school connectedness, which were in turn significantly and positively associated with civic engagement. In addition, school climate was significantly and positively associated with greater academic self-efficacy, but academic self-efficacy was not significantly associated with civic engagement. Tests of mediation indicated there was one significant indirect pathway between school climate and civic engagement behavior. There was an indirect association between school climate and civic engagement via its association with sense of school connectedness, indirect association estimate = .17 [95% CI: .08, .32]. The aforementioned indirect association via school connectedness accounted for 50% (.17/.34) of the total effect. Partial support was found for the prediction that students’ perceptions of a positive school climate are linked to civic engagement in part through their role in students’ sense of connection to school.

Keywords: civic engagement, early adolescence, school climate, school belonging, developmental niche

Procedia PDF Downloads 366

Authors: Junyu Chen, Peng Xu

Abstract:

In the context of global efforts to enhance building energy efficiency, accurate thermal load forecasting is crucial for both device sizing and predictive control. Variable Refrigerant Flow (VRF) systems are widely used in buildings around the world, yet VRF zonal load prediction has received limited attention. Due to differences between VRF zones in building-level prediction methods, zone-level load forecasting could significantly enhance accuracy. Given that modern VRF systems generate high-quality data, this paper introduces transfer learning to leverage this data and further improve prediction performance. This framework also addresses the challenge of predicting load for building zones with no historical data, offering greater accuracy and usability compared to pure white-box models. The study first establishes an initial variable set of VRF zonal building loads and generates a foundational white-box database using EnergyPlus. Key variables for VRF zonal loads are identified using methods including SRRC, PRCC, and Random Forest. XGBoost and LSTM are employed to generate pre-trained black-box models based on the white-box database. Finally, real-world data is incorporated into the pre-trained model using transfer learning to enhance its performance in operational buildings. In this paper, zone-level load prediction was integrated with transfer learning, and a framework was proposed to improve the accuracy and applicability of VRF zonal load prediction.

Keywords: zonal load prediction, variable refrigerant flow (VRF) system, transfer learning, energyplus

Procedia PDF Downloads 18

Authors: M. V. Manoj Kumar, Likewin Thomas, Annappa

Abstract:

Process mining provides methods and techniques for analyzing event logs recorded in modern information systems that support real-world operations. While analyzing an event-log, state-of-the-art techniques available in process mining believe that the operational process as a static entity (stationary). This is not often the case due to the possibility of occurrence of a phenomenon called concept drift. During the period of execution, the process can experience concept drift and can evolve with respect to any of its associated perspectives exhibiting various patterns-of-change with a different pace. Work presented in this paper discusses the main aspects to consider while addressing concept drift phenomenon and proposes a method for detecting and localizing the sudden concept drifts in control-flow perspective of the process by using features extracted by processing the traces in the process log. Our experimental results are promising in the direction of efficiently detecting and localizing concept drift in the context of process mining research discipline.

Keywords: abrupt drift, concept drift, sudden drift, control-flow perspective, detection and localization, process mining

Procedia PDF Downloads 343

Authors: Alexander Blokhin, Ekaterina Kruglova, Boris Semisalov

Abstract:

Mathematical model based on the mesoscopic theory of polymer dynamics is developed for numerical simulation of the flows of polymeric liquid between two coaxial cylinders. This model is a system of nonlinear partial differential equations written in the cylindrical coordinate system and coupled with the heat conduction equation including a specific dissipation term. The stationary flows similar to classical Poiseuille ones are considered, and the resolving equations for the velocity of flow and for the temperature are obtained. For solving them, a fast pseudospectral method is designed based on Chebyshev approximations, that enables one to simulate the flows through the channels with extremely small relative values of the radius of inner cylinder. The numerical analysis of the dependance of flow on this radius and on the values of dissipation constant is done.

Keywords: dynamics of polymeric liquid, heat dissipation, singularly perturbed problem, pseudospectral method, Chebyshev polynomials, stabilization technique

Procedia PDF Downloads 288

Authors: Muluegziabher Semagne Mekonnen

Abstract:

This study was intended to show the irrigation water requirements and evaluation of canal hydraulics steady state conditions to improve on scheme performance of the Meki-Ziway irrigation project. The methodology used was the CROPWAT 8.0 model to estimate the irrigation water requirements of five major crops irrigated in the study area. The results showed that for the whole existing and potential irrigation development area of 2000 ha and 2599 ha, crop water requirements were 3,339,200 and 4,339,090.4 m³, respectively. Hydraulic simulation models are fundamental tools for understanding the hydraulic flow characteristics of irrigation systems. Hydraulic simulation models are fundamental tools for understanding the hydraulic flow characteristics of irrigation systems. In this study Hydraulic Analysis of Irrigation Canals Using HEC-RAS Model was conducted in Meki-Ziway Irrigation Scheme. The HEC-RAS model was tested in terms of error estimation and used to determine canal capacity potential.

Keywords: HEC-RAS, irrigation, hydraulic. canal reach, capacity

Procedia PDF Downloads 55

Authors: Jiajia Peng, Yijun Dong, Jianjun Ren, Yu Zhao

Abstract:

Objectives: Understanding the association between sleep traits and tinnitus could help prevent and provide appropriate interventions against tinnitus. Therefore, this study aimed to assess the relationship between different sleep patterns and tinnitus. Design: A cross-sectional analysis using baseline data (2006–2010, n=168,064) by logistic regressions was conducted to evaluate the association between sleep traits (including the overall health sleep score and five sleep behaviors), and the occurrence (yes/no), frequency (constant/transient), and severity (upsetting/not upsetting) of tinnitus. Further, a prospective analysis of participants without tinnitus at baseline (n=9,581) was performed, who had been followed up for seven years (2012–2019) to assess the association between new-onset tinnitus and sleep characteristics. Moreover, a subgroup analysis was also carried out to estimate the differences in sex by dividing the participants into male and female groups. A sensitivity analysis was also conducted by excluding ear-related diseases to avoid their confounding effects on tinnitus (n=102,159). Results: In the cross-sectional analysis, participants with “current tinnitus” (OR: 1.13, 95% CI: 1.04–1.22, p=0.004) had a higher risk of having a poor overall healthy sleep score and unhealthy sleep behaviors such as short sleep durations (OR: 1.09, 95% CI: 1.04–1.14, p<0.001), late chronotypes (OR: 1.09, 95% CI: 1.05–1.13, p<0.001), and sleeplessness (OR: 1.16, 95% CI: 1.11–1.22, p<0.001) than those participants who “did not have current tinnitus.” However, this trend was not obvious between “constant tinnitus” and “transient tinnitus.” When considering the severity of tinnitus, the risk of “upsetting tinnitus” was obviously higher if participants had lower overall healthy sleep scores (OR: 1.31, 95% CI: 1.13–1.53, p<0.001). Additionally, short sleep duration (OR: 1.22, 95% CI: 1.12–1.33, p<0.001), late chronotypes (OR: 1.13, 95% CI: 1.04–1.22, p=0.003), and sleeplessness (OR: 1.43, 95% CI: 1.29–1.59, p<0.001) showed positive correlations with “upsetting tinnitus.” In the prospective analysis, sleeplessness presented a consistently significant association with “upsetting tinnitus” (RR: 2.28, P=0.001). Consistent results were observed in the sex subgroup analysis, where a much more pronounced trend was identified in females compared with males. The results of the sensitivity analysis were consistent with those of the cross-sectional and prospective analyses. Conclusions: Different types of sleep disturbance may be associated with the occurrence and severity of tinnitus; therefore, precise interventions for different types of sleep disturbance, particularly sleeplessness, may help in the prevention and treatment of tinnitus.

Keywords: tinnitus, sleep, sleep behaviors, sleep disturbance

Procedia PDF Downloads 138

Authors: Lam Pham, Peter Hubber, Russell Tytler

Abstract:

Students’ conceptual understandings of chemistry concepts/phenomena involve capability to coordinate across the three levels of Johnston’s triangle model. This triplet model is based on reasoning about chemical phenomena across macro, sub-micro and symbolic levels. In chemistry education, there is a need for further examining inquiry-based approaches that enhance students’ conceptual learning and problem solving skills. This research adopted a directed inquiry pedagogy based on students constructing and coordinating representations, to investigate senior school students’ capabilities to flexibly move across Johnston’ levels when learning dilution and molar concentration concepts. The participants comprise 50 grade 11 and 20 grade 10 students and 4 chemistry teachers who were selected from 4 secondary schools located in metropolitan Melbourne, Victoria. This research into classroom practices used ethnographic methodology, involved teachers working collaboratively with the research team to develop representational activities and lesson sequences in the instruction of a unit on solution chemistry. The representational activities included challenges (Representational Challenges-RCs) that used ‘representational tools’ to assist students to move across Johnson’s three levels for dilution phenomena. In this report, the ‘representational tool’ called ‘cross and portion’ model was developed and used in teaching and learning the molar concentration concept. Students’ conceptual understanding and problem solving skills when learning with this model are analysed through group case studies of year 10 and 11 chemistry students. In learning dilution concepts, students in both group case studies actively conducted a practical experiment, used their own language and visualisation skills to represent dilution phenomena at macroscopic level (RC1). At the sub-microscopic level, students generated and negotiated representations of the chemical interactions between solute and solvent underpinning the dilution process. At the symbolic level, students demonstrated their understandings about dilution concepts by drawing chemical structures and performing mathematical calculations. When learning molar concentration with a ‘cross and portion’ model (RC2), students coordinated across visual and symbolic representational forms and Johnson’s levels to construct representations. The analysis showed that in RC1, Year 10 students needed more ‘scaffolding’ in inducing to representations to explicit the form and function of sub-microscopic representations. In RC2, Year 11 students showed clarity in using visual representations (drawings) to link to mathematics to solve representational challenges about molar concentration. In contrast, year 10 students struggled to get match up the two systems, symbolic system of mole per litre (‘cross and portion’) and visual representation (drawing). These conceptual problems do not lie in the students’ mathematical calculation capability but rather in students’ capability to align visual representations with the symbolic mathematical formulations. This research also found that students in both group case studies were able to coordinate representations when probed about the use of ‘cross and portion’ model (in RC2) to demonstrate molar concentration of diluted solutions (in RC1). Students mostly succeeded in constructing ‘cross and portion’ models to represent the reduction of molar concentration of the concentration gradients. In conclusion, this research demonstrated how the strategic introduction and coordination of chemical representations across modes and across the macro, sub-micro and symbolic levels, supported student reasoning and problem solving in chemistry.

Keywords: cross and portion, dilution, Johnston's triangle, molar concentration, representations

Procedia PDF Downloads 135

Authors: Hanan Mikhael Dawood, Afaneen Anwer Abood Al-Khazraji

Abstract:

The paper presents an investigation of field oriented control strategy of Permanent Magnet Synchronous Motor (PMSM) based on hardware in the loop simulation (HIL) over a wide speed range. A sensorless rotor position estimation using sliding mode observer for permanent magnet synchronous motor is illustrated considering the effects of magnetic saturation between the d and q axes. The cross saturation between d and q axes has been calculated by finite-element analysis. Therefore, the inductance measurement regards the saturation and cross saturation which are used to obtain the suitable id-characteristics in base and flux weakening regions. Real time matrix multiplication in Field Programmable Gate Array (FPGA) using floating point number system is used utilizing Quartus-II environment to develop FPGA designs and then download these designs files into development kit. dSPACE DS1103 is utilized for Pulse Width Modulation (PWM) switching and the controller. The hardware in the loop results conducted to that from the Matlab simulation. Various dynamic conditions have been investigated.

Keywords: magnetic saturation, rotor position estimation, sliding mode observer, hardware in the loop (HIL)

Procedia PDF Downloads 521

Authors: Tingyu Zhang

Abstract:

The cross-basin ecological compensation mechanism is key to stimulating active participation in ecological protection across the entire basin. This study constructs an evolutionary game model of cross-basin ecological compensation in the Yangtze River Economic Belt (YREB), introducing a central government constraint and incentive mechanism (CGCIM) to explore the conditions for achieving strategies of protection and compensation that meet societal expectations. Furthermore, using a water quality-water quantity model combined with factual data from the YREB in 2020, the amount of ecological compensation is calculated. The results indicate that the stability of the evolutionary game model of the upstream and downstream governments in the YREB is closely related to the CGCIM. When the sum of the central government's reward amount to the upstream government and the penalty amount to both sides simultaneously is greater than 39.948 billion yuan, and the sum of the reward amount to the downstream government and the penalty amount to only the lower reaches is greater than 1.567 billion yuan, or when the sum of the reward amount to the downstream government and the penalty amount to both sides simultaneously is greater than 1.567 billion yuan, and the sum of the reward amount to the upstream government and the penalty amount to only the upstream government is greater than 399.48 billion yuan, the protection and compensation become the only evolutionarily stable strategy for the evolutionary game system composed of the upstream and downstream governments in the YREB. At this point, the total ecological compensation that the downstream government of the YREB should pay to the upstream government is 1.567 billion yuan, with Hunan paying 0.03 billion yuan, Hubei 2.53 billion yuan, Jiangxi 0.18 billion yuan, Anhui 1.68 billion yuan, Zhejiang 0.75 billion yuan, Jiangsu 6.57 billion yuan, and Shanghai 3.93 billion yuan. The research results can provide a reference for promoting the improvement and perfection of the cross-basin ecological compensation system in the YREB.

Keywords: ecological compensation, evolutionary game model, central government constraint and incentive mechanism, Yangtze river economic belt

Procedia PDF Downloads 60

Authors: Hande Barkan-Ozturk, Angelika Menner, Alexander Bismarck

Abstract:

Microfluidic mixing technology grew rapidly in the past few years due to its many advantages over the macro-scale mixing, especially the ability to use small amounts of internal volume and also very high surface-to-volume ratio. The Reynold number identify whether the mixing is operated by the laminar or turbulence flow. Therefore, mixing with very fast kinetic can be achieved by diminishing the channel dimensions to decrease Reynold number and the laminar flow can be accomplished. Moreover, by using obstacles in the micromixer, the mixing length and the contact area between the species have been increased. Therefore, the channel geometry and its surface property have great importance to reach satisfactory mixing results. Since poly(-merised) High Internal Phase Emulsions (polyHIPEs) have more than 74% porosity and their pores are connected each other with pore throats, which cause high permeability, they are ideal candidate to build a micromixer. The HIPE precursor is commonly produced by using an overhead stirrer to obtain relatively large amount of emulsion in batch process. However, we will demonstrate that a desired amount of emulsion can be prepared continuously with micromixer build from polyHIPE, and such HIPE can subsequently be employed as ink in 3D printing process. In order to produce the micromixer a poly-Pickering(St-co-DVB)HIPE with 80% porosity was prepared with modified silica particles as stabilizer and surfactant Hypermer 2296 to obtain open porous structure and after coating of the surface, the three 1/16' ' PTFE tubes to transfer continuous (CP) and internal phases (IP) and the other is to collect the emulsion were placed. Afterwards, the two phases were injected in the ratio 1:3 CP:IP with syringe dispensers, respectively, and highly viscoelastic H(M)IPE, which can be used as an ink in 3D printing process, was gathered continuously. After the polymerisation of the resultant emulsion, polyH(M)IPE has interconnected porous structure identical to the monolithic polyH(M)IPE indicating that the emulsion can be prepared constantly with poly-Pickering-HIPE as micromixer and it can be used to prepare desired pattern with a 3D printer. Moreover, the morphological properties of the emulsion can be adjustable by changing flow ratio, flow speed and structure of the micromixer.

Keywords: 3D-Printing, emulsification, macroporous polymer, micromixer, polyHIPE

Procedia PDF Downloads 159

Authors: Mário Ernesto Sitoe, Orlando Zacarias

Abstract:

University education is influenced by several factors that range from the adoption of strategies to strengthen the whole process to the academic performance improvement of the students themselves. This work uses data mining techniques to develop a predictive model to identify students with a tendency to evasion and retention. To this end, a database of real students’ data from the Department of University Admission (DAU) and the Department of Mathematics and Informatics (DMI) was used. The data comprised 388 undergraduate students admitted in the years 2009 to 2014. The Weka tool was used for model building, using three different techniques, namely: K-nearest neighbor, random forest, and logistic regression. To allow for training on multiple train-test splits, a cross-validation approach was employed with a varying number of folds. To reduce bias variance and improve the performance of the models, ensemble methods of Bagging and Stacking were used. After comparing the results obtained by the three classifiers, Logistic Regression using Bagging with seven folds obtained the best performance, showing results above 90% in all evaluated metrics: accuracy, rate of true positives, and precision. Retention is the most common tendency.

Keywords: evasion and retention, cross-validation, bagging, stacking

Procedia PDF Downloads 78

Authors: Jatuporn Juyjingam, Pitak Siriwong

Abstract:

This paper presents a study of factors effecting the success and failure of social enterprise in Thailand identifying communication as one of the criteria for measuring the social impact of social enterprise. The study focused on the communication driver of the SCALERS model. The research examines how communication is viewed in Thailand social enterprise. The research aims to determine how selected social enterprise uses communication in their operations. More specifically, the study aims to 1) describe the profile of social enterprise in Thailand, 2) identify the different roles of communication in the operation of social enterprise in Thailand, 3) determine Thailand social enterprise concept of communication. The study made use of the case study and cross case study research designs. For the profiling of the social enterprises, the case study was used. The researchers made use of the cross-case research design in identifying trends across the ten social enterprises and in determining the social entrepreneurs’ concept of communication. Key informant interviews were conducted with the heads or representatives of selected social enterprises, a three-part interview schedule was used to facilitate data gathering. The three parts included are 1) Profile of social enterprise in Thailand 2) How social enterprises apply communication in their operations 3) What is the key success in using communication among social enterprise in Thailand. This study is an exploratory research.

Keywords: communication, social entrepreneurship, social enterprise, sustainability development

Procedia PDF Downloads 495

Authors: Mahmoud Nassar

Abstract:

This paper was designed for interviews with companies that had implemented Management Accounting Innovations (MAIs) within Jordanian Industrial Sector in full. Each company in this paper was examined as an entity to obtain an understanding of the process of MAIs adoption and implementation as well as the respondents’ opinions and perspectives of each individual company as to what are considered to be the important factors in the company. By firstly using within-case analysis has the potential to aid in-depth views of the issues and their impact on each particular company. Then, cross-case analysis was used to analyse the similarities and differences of the six companies. The study concludes that, the six companies interviewed gradually moved to using MAIs over the last ten years. The length of time required to implement the MAIs varied across the companies. Interviewees revealed several factors from both the demand and supply side that influence implementation of MAIs within the Jordanian industrial companies. Respondents mentioned and emphasised the important effect of the following factors: top management support, education about ABC concept and benefits, training programmes, shortcoming of existing cost system, competition, size of company, professional accounting bodies, management accounting journals, management accounting research and PhD degrees, and cooperation between universities and companies.

Keywords: industrial sector, innovations, Jordan, management accounting

Procedia PDF Downloads 366

Authors: Núria Arimany Serrat, Xavier Ferràs Hernández, Petra A. Nylund, Eric Viardot

Abstract:

Innovation is an increasingly important antecedent to firm competitiveness and growth. Successful innovation, however, requires a significant financial commitment and the means of financing accessible to the firm may affect its ability to innovate. The access to equity financing such as venture capital has been connected to innovativeness for young firms. For established enterprises, debt financing of innovation may be a more realistic option. Continuous innovation and growth would otherwise require a constant increase of equity. We, therefore, investigate the relation between debt financing and innovation for large firms and hypothesize that those firms that carry more debt will be more innovative. The need for debt financing of innovation may be reduced for very profitable firms, which can finance innovation with cash flow. We thus hypothesize a moderating effect of profitability on the relationship between debt financing and innovation. We carry out an empirical investigation using a longitudinal data set including 167 large European firms over five years, resulting in 835 firm years. We apply generalized least squares (GLS) regression with fixed firm effects to control for firm heterogeneity. The findings support our hypotheses and we conclude that access to debt finding is an important antecedent of innovation, with profitability as a moderating factor. The results do however differ across national innovation systems and we find a strong relationship for British, Dutch, French, and Italian firms but not for German and Spanish entities. We discuss differences in the national systems of innovation and financing which contextualize the variations in the findings and thus make a nuanced contribution to the research in innovation financing. The cross-country differences calls for differentiated advice to managers, institutions, and researchers depending on the national context.

Keywords: innovation, R&D, national innovation systems, financing

Procedia PDF Downloads 528

Authors: Anubhav Kumar Dwivedi, Arshad Khan, S. N. Tripathi, Manish Joshi, Gaurav Mishra, Dinesh Nath, Naveen Tiwari, B. K. Sapra

Abstract:

In a nuclear reactor accident scenario, a large number of fission products may release to the piping system of the primary heat transport. The released fission products, mostly in the form of the aerosol, get deposited on the inner surface of the piping system mainly due to gravitational settling and thermophoretic deposition. The removal processes in the complex piping system are controlled to a large extent by the thermal-hydraulic conditions like temperature, pressure, and flow rates. These parameters generally vary with time and therefore must be carefully monitored to predict the aerosol behavior in the piping system. The removal process of aerosol depends on the size of particles that determines how many particles get deposit or travel across the bends and reach to the other end of the piping system. The released aerosol gets deposited onto the inner surface of the piping system by various mechanisms like gravitational settling, Brownian diffusion, thermophoretic deposition, and by other deposition mechanisms. To quantify the correct estimate of deposition, the identification and understanding of the aforementioned deposition mechanisms are of great importance. These mechanisms are significantly affected by different flow and thermodynamic conditions. Thermophoresis also plays a significant role in particle deposition. In the present study, a series of experiments were performed in the piping system of the National Aerosol Test Facility (NATF), BARC using metal aerosols (zinc) in dry environments to study the spatial distribution of particles mass and number concentration, and their depletion due to various removal mechanisms in the piping system. The experiments were performed at two different carrier gas flow rates. The commercial CFD software FLUENT is used to determine the distribution of temperature, velocity, pressure, and turbulence quantities in the piping system. In addition to the in-built models for turbulence, heat transfer and flow in the commercial CFD code (FLUENT), a new sub-model PBM (population balance model) is used to describe the coagulation process and to compute the number concentration along with the size distribution at different sections of the piping. In the sub-model coagulation kernels are incorporated through user-defined function (UDF). The experimental results are compared with the CFD modeled results. It is found that most of the Zn particles (more than 35 %) deposit near the inlet of the plenum chamber and a low deposition is obtained in piping sections. The MMAD decreases along the length of the test assembly, which shows that large particles get deposited or removed in the course of flow, and only fine particles travel to the end of the piping system. The effect of a bend is also observed, and it is found that the relative loss in mass concentration at bends is more in case of a high flow rate. The simulation results show that the thermophoresis and depositional effects are more dominating for the small and larger sizes as compared to the intermediate particles size. Both SEM and XRD analysis of the collected samples show the samples are highly agglomerated non-spherical and composed mainly of ZnO. The coupled model framed in this work could be used as an important tool for predicting size distribution and concentration of some other aerosol released during a reactor accident scenario.

Keywords: aerosol, CFD, deposition, coagulation

Procedia PDF Downloads 138

Authors: Antonio Pratelli, Lorenzo Brocchini, Reginald Roy Souleyrette

Abstract:

A rotary is a traffic circle intersection where vehicles entering from branches give priority to circulating flow. Vehicles entering the intersection from converging roads move around the central island and weave out of the circle into their desired exiting branch. This creates merging and diverging conflicts among any entry and its successive exit, i.e., a section. Therefore, rotary capacity models are usually based on the weaving of the different movements in any section of the circle, and the maximum rate of flow value is then related to each weaving section of the rotary. Nevertheless, the single-section capacity value does not lead to the typical performance characteristics of the intersection, such as the entry average delay which is directly linked to its level of service. From another point of view, modern roundabout capacity models are based on the limitation of the flow entering from the single entrance due to the amount of flow circulating in front of the entrance itself. Modern roundabouts capacity models generally lead also to a performance evaluation. This paper aims to incorporate a modern roundabout capacity model into an old rotary capacity method to obtain from the latter the single input capacity and ultimately achieve the related performance indicators. Put simply; the main objective is to calculate the average delay of each single roundabout entrance to apply the most common Highway Capacity Manual, or HCM, criteria. The paper is organized as follows: firstly, the rotary and roundabout capacity models are sketched, and it has made a brief introduction to the model combination technique with some practical instances. The successive section is deserved to summarize the TRRL old rotary capacity model and the most recent HCM-7th modern roundabout capacity model. Then, the two models are combined through an iteration-based algorithm, especially set-up and linked to the concept of roundabout total capacity, i.e., the value reached due to a traffic flow pattern leading to the simultaneous congestion of all roundabout entrances. The solution is the average delay for each entrance of the rotary, by which is estimated its respective level of service. In view of further experimental applications, at this research stage, a collection of existing rotary intersections operating with the priority-to-circle rule has already started, both in the US and in Italy. The rotaries have been selected by direct inspection of aerial photos through a map viewer, namely Google Earth. Each instance has been recorded by location, general urban or rural, and its main geometrical patterns. Finally, conclusion remarks are drawn, and a discussion on some further research developments has opened.

Keywords: mixed methods, old rotary and modern roundabout capacity models, total capacity algorithm, level of service estimation

Procedia PDF Downloads 78

Authors: A. Bahmanpour, I. Eames, C. Klettner, A. Dimakopoulos

Abstract:

We develop a new set of diagnostic tools to analyze inundation into a model district using three-dimensional CFD simulations, with a view to generating a database against which to test simpler models. A three-dimensional model of Oregon city with different-sized groups of building next to the coastline is used to run calculations of the movement of a long period wave on the shore. The initial and boundary conditions of the off-shore water are set using a nonlinear inverse method based on Eulerian spatial information matching experimental Eulerian time series measurements of water height. The water movement is followed in time, and this enables the pressure distribution on every surface of each building to be followed in a temporal manner. The three-dimensional numerical data set is validated against published experimental work. In the first instance, we use the dataset as a basis to understand the success of reduced models - including 2D shallow water model and reduced 1D models - to predict water heights, flow velocity and forces. This is because models based on the shallow water equations are known to underestimate drag forces after the initial surge of water. The second component is to identify critical flow features, such as hydraulic jumps and choked states, which are flow regions where dissipation occurs and drag forces are large. Finally, we describe how future tsunami inundation models should be modified to account for the complex effects of buildings through drag and blocking.Financial support from UCL and HR Wallingford is greatly appreciated. The authors would like to thank Professor Daniel Cox and Dr. Hyoungsu Park for providing the data on the Seaside Oregon experiment.

Keywords: computational fluid dynamics, extreme events, loading, tsunami

Procedia PDF Downloads 113