Search results for: electrical characteristics of capacitive touchscreen
Commenced in January 2007
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Edition: International
Paper Count: 9159

Search results for: electrical characteristics of capacitive touchscreen

4659 Circular Raft Footings Strengthened by Stone Columns under Dynamic Harmonic Loads

Authors: R. Ziaie Moayed, A. Mahigir

Abstract:

Stone column technique has been successfully employed to improve the load-settlement characteristics of foundations. A series of finite element numerical analyses of harmonic dynamic loading have been conducted on strengthened raft footing to study the effects of single and group stone columns on settlement of circular footings. The settlement of circular raft footing that improved by single and group of stone columns are studied under harmonic dynamic loading. This loading is caused by heavy machinery foundations. A detailed numerical investigation on behavior of single column and group of stone columns is carried out by varying parameters like weight of machinery, loading frequency and period. The result implies that presence of single and group of stone columns enhanced dynamic behavior of the footing so that the maximum and residual settlement of footing significantly decreased. 

Keywords: finite element analysis, harmonic loading, settlement, stone column

Procedia PDF Downloads 369
4658 Essential Elements and Trace Metals on a Continuously Cultivated and Fertilised Field

Authors: Pholosho M. Kgopa, Phatu W. Mashela

Abstract:

Due to high incidents of marginal land in Limpopo Province, South Africa, and increasing demand for arable land, small-holder farmers tend to continuously cultivate the same fields and at the same time, applying fertilisers to improve yields for meeting local food security. These practices might have an impact on the distribution of trace and essential elements. Therefore, the objective of this investigation was to assess the distribution of essential elements and trace metals in a continuously cultivated and fertilised field, at the University of Limpopo Experimental Farm. Three fields, 3 ha each were identified as continuously cultivated (CC), moderately cultivated (MC) and virgin fields (VF). Each field was divided into 12 equal grids of 50 m × 50 m for sampling. A soil profile was opened in each grid, where soil samples were collected from 0-20; 20-40 and 40-60; 60-80 and 80-100 cm depths for analysis. Samples were analysed for soil texture, pH, electrical conductivity, organic matter content, selected essential elements (Ca, P and Mg), Na and trace elements (Cu, Fe, Ni, and Zn). Results suggested that most of the variables were vertically different, with high concentrations of the test elements except for magnesium. Soil pH in depth 0-20 cm was high (6.44) in CC when compared to that in VF (5.29), but lower than that of MC (7.84). There were no distinctive vertical trends of the variables, except for Mg, Na, and K which displayed a declining trend at 40-60 cm depth when compared to the 0-20 cm depth. Concentrations of Fe, Cu, Zn, and Ni were generally low which might be due to their indirect relationship with soil pH. Continuous cultivation and fertilisation altered soil chemical properties; which could explain the unproductivity of such fields.

Keywords: over-cultivation, soil chemical properties, vertical distribution, spatial distribution

Procedia PDF Downloads 185
4657 The Motion of Ultrasonically Propelled Nanomotors Operating in Biomimetic Environments

Authors: Suzanne Ahmed

Abstract:

Nanomotors, also commonly referred to as nanorobotics or nanomachines, have garnered considerable research attention due to their numerous potential applications in biomedicine, including drug delivery and microsurgery. Nanomotors typically consist of inorganic or polymeric particles that are powered to undergo motion. These artificial, man-made nanoscale motors operate in the low Reynolds number regime and typically have no moving parts. Several methods have been developed to actuate the motion of nanomotors including magnetic fields, electrical fields, electromagnetic waves, and chemical fuel. Since their introduction in 2012, ultrasonically powered nanomotors have been explored in biocompatible fluids and even within living cells. Due to the common use of ultrasound within the biomedical community for both imaging and therapeutics, the introduction of ultrasonically propelled nanomotors holds significant potential for biomedical applications. In this work, metallic nanomotors are electrochemically plated within porous anodic alumina templates to have a diameter of 300 nm and a length that is 2-4 µm. Nanomotors are placed within an acoustic chamber capable of producing bulk acoustic waves in the ultrasonic range. The motion of nanomotors within biomimetic confines is explored. The control over nanomotor motion is exerted by virtue of the properties of the acoustic signal within these biomimetic confines to control speed, modes of motion and directionality of motion. To expand the range of control over nanorod motion within biomimetic confines, external forces from biocompatible magnetic fields, are exerted onto the acoustically propelled nanomotors.

Keywords: nanomotors, nanomachines, nanorobots, ultrasound

Procedia PDF Downloads 71
4656 Research on Models and Selection of Entry Strategies for Catering Industry Based on the Evolutionary Game Theory

Authors: Jianxin Zhu, Na Liu

Abstract:

Entry strategies play a vital role in the development of new enterprises in the catering industry. Different entry strategies will have different effects on the development of new enterprise. Based on the research of scholars at home and abroad, and combining the characteristics of the catering industry, the entry strategies are divided into low-price entry strategies and high-quality entry strategies. Facing the entry of new enterprise, the strategies of incumbent enterprises are divided into response strategies and non-response strategies. This paper uses evolutionary game theory to study the strategic interaction mechanism between incumbent companies and new enterprises. When different initial values and parameter values are set, which strategy will the two-game subjects choose, respectively? Using matlab2016 for numerical simulation, the results show that the choice of strategies for new enterprise and incumbent enterprise is influenced by more than one factor, and the system has different evolution trends under different circumstances. When the parameters were set, the choice of two subjects' strategies mainly depends on the net profit between the strategies.

Keywords: catering industry, entry strategy, evolutionary game, strategic interaction mechanism

Procedia PDF Downloads 123
4655 The Effect of Bearing Surface Finish on the Engine's Lubrication System Performance

Authors: Kudakwashe Diana Nyamugure

Abstract:

Engine design has evolved to suit new industry standards of smaller compact designs that operate at high temperatures and even higher stress loads. Research has proven that the interaction of the bearing surface and the lubrication film is affected by the bearing's surface texture, geometry, and dimensional tolerances. The challenge now for the automotive manufacturing industry is to understand which processes can be applied on bearing surfaces to reduce the 65% energy loss in engines, 15% of which is caused by friction. This paper will discuss a post grinding process known as microfinishing which optimises the characteristics of a manufactured surface such as roughness, profile, and waviness. Microfinishing is becoming an increasing trend within the automotive industry and has so far been applied on high performance and mass production crank or cam bearing surfaces in bid of friction reduction and extended engine service life. In the near future, microfinishing will be applied to more engine components because of the stringent environmental regulations demands on fuel consumption, reliability, power, and service life of engine components.

Keywords: bearings, tribology, friction reduction, energy efficiency

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4654 The Role of Smartphones on Iranian Couples' Relationship: An Analysis

Authors: Niloofar Hooman

Abstract:

The present study aims at investigating the positive and negative effects of using Smartphones on couples committed relationships. Despite the fact that many couples may benefit from the positive aspects of Smartphones, it is not clear how their feeling of trust, intimacy and connection in their relationships get affected by Smartphones. This is important as it highlights the ambivalent influences of Smartphones on couple’s relationships. On the one hand, Smartphones can enhance their social and emotional interactions and on the other hand, they can cause mistrust and isolation between them. Trust, intimacy and honesty are of important factors through which a stable relationship can be constructed. Nevertheless, some characteristics of Smartphones such as being fluid and personalized can harm the relationship and consequently destroy it. Thus, it is necessary to investigate how Iranian couples in committed relationships use Smartphone to manage their relationship and how couples feel Smartphone have enhanced or detracted a sense of trust, intimacy and connection with their partner? In the first phase of the study, in-depth-interview will be conducted with 30 couples and data will be analyzed using NVIVO software. In the next phase of the study, 1500 participants aged 20 and above will be selected based on cluster sampling. Data will be analyzed both qualitatively and quantitatively.

Keywords: couple, family, internet, intimacy, Smartphone, trust

Procedia PDF Downloads 388
4653 The Sexual Knowledge, Attitudes and Behaviors of College Students from Only-Child Families: A National Survey in China

Authors: Jiashu Shen

Abstract:

This study aims at exploring the characteristics of sexual knowledge, attitudes, and behaviors of Chinese college students from the 'one-child' families compared with those with siblings. This study utilized the data from the 'National College Student Survey on Sexual and Reproductive Health 2019'. Multiple logistic regression analyses were used to assess the association between the 'only-child' and their sexual knowledge, sexual attitudes, sexual behaviors, and risky sexual behaviors (RSB) stratified by sex and home regions, respectively. Compared with students with siblings, the 'only-child' students scored higher in sex-related knowledge (only-child students: 4.49 ± 2.28, students with siblings: 3.60 ± 2.27). Stronger associations between only-child and more liberal sexual attitudes were found in urban areas, including the approval of premarital sexual intercourse (OR: 1.51, 95% CI: 1.50-1.65) and multiple sexual partners (OR: 1.85, 95% CI: 1.72-1.99). For risky sexual behaviors, being only-child is more likely to use condoms in first sexual intercourse, especially among male students (OR: 0.68, 95% CI: 0.58-0.80). Only-child students are more likely to have more sexual knowledge, more liberal sexual attitude, and less risky sexual behavior. Further health policy and sex education should focus more on students with siblings.

Keywords: attitudes and behaviors, only-child students, sexual knowledge, students with siblings

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4652 Investigation of the Relationship between Personality Components and Tendency to Addiction to Domestic Violence

Authors: Mohamad Reza Khodabakhsh

Abstract:

Violence against women is a historical phenomenon; although its form and type are common in various societies and cultures, this type of violence occurs in terms of physical, psychological, financial, and sexual dimensions. This is the cause of many social deviations and endangers the center of the family as the most important institution. This research seeks to investigate the relationship between personality characteristics and the tendency to addiction to domestic violence. One hundred fifty women and one hundred fifty men were selected by the available sampling method. One hundred fifty men were admitted to drug addiction camps, and women included domestic violence cases. A questionnaire on addiction tendency, Five Personality Traits (NEO), and attitudes toward violence against women was used. Data were analyzed in descriptive and inferential statistics. The data were analyzed at the level of descriptive mean, mean, and standard deviation and analyzed using SPSS 20 software using correlation and analysis of variance at the level of inferential level. And the data were analyzed at the p≤0.05 significance level. The results showed that there is a significant relationship between personality traits and a tendency to addiction and domestic violence.

Keywords: personality, addiction, domestic violence, family

Procedia PDF Downloads 100
4651 Influence of Nanozeolite Particles on Improvement of Clayey Soil

Authors: A. Goodarzian, A. Ghasemipanah, R. Ziaie Moayed, H. Niroumand

Abstract:

The problem of soil stabilization has been one of the important issues in geotechnical engineering. Nowadays, nanomaterials have revolutionized many industries. In this research, improvement of the Kerman fine-grained soil by nanozeolite and nanobentonite additives separately has been investigated using Atterberg Limits and unconfined compression test. In unconfined compression test, the samples were prepared with 3, 5 and 7% nano additives, with 1, 7 and 28 days curing time with strain control method. Finally, the effect of different percentages of nanozeolite and nanobentonite on the geotechnical behavior and characteristics of Kerman fine-grained soil was investigated. The results showed that with increasing the amount of nanozeolite and also nanobentonite to fine-grained soil, the soil exhibits more compression strength. So that by adding 7% nanozeolite and nanobentonite with 1 day curing, the unconfined compression strength is 1.18 and 2.1 times higher than the unstabilized soil. In addition, the failure strain decreases in samples containing nanozeolite, whereas it increases in the presence of nanobentonite. Increasing the percentage of nanozeolite and nanobentonite also increased the elasticity modulus of soil.

Keywords: nanoparticles, soil improvement, clayey soil, unconfined compression stress

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4650 NaCl Erosion-Corrosion of Mild Steel under Submerged Impingement Jet

Authors: M. Sadique, S. Ainane, Y. F. Yap, P. Rostron, E. Al Hajri

Abstract:

The presence of sand in production lines in the oil and gas industries causes material degradation due to erosion-corrosion. The material degradation caused by erosion-corrosion in pipelines can result in a high cost of monitoring and maintenance and in major accidents. The process of erosion-corrosion consists of erosion, corrosion, and their interactions. Investigating and understanding how the erosion-corrosion process affects the degradation process in certain materials will allow for a reduction in economic loss and help prevent accidents. In this study, material loss due to erosion-corrosion of mild steel under impingement of sand-laden water at 90˚ impingement angle is investigated using a submerged impingement jet (SIJ) test. In particular, effects of jet velocity and sand loading on TWL due to erosion-corrosion, weight loss due to pure erosion and erosion-corrosion interactions, at a temperature of 29-33 °C in sea water environment (3.5% NaCl), are analyzed. The results show that the velocity and sand loading have a great influence on the removal of materials, and erosion is more dominant under all conditions studied. Changes in the surface characteristics of the specimen after impingement test are also discussed.

Keywords: erosion-corrosion, flow velocity, jet impingement, sand loading

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4649 Development of Polymeric Fluorescence Sensor for the Determination of Bisphenol-A

Authors: Neşe Taşci, Soner Çubuk, Ece Kök Yetimoğlu, M. Vezir Kahraman

Abstract:

Bisphenol-A (BPA), 2,2-bis(4-hydroxyphenly)propane, is one of the highest usage volume chemicals in the world. Studies showed that BPA maybe has negative effects on the central nervous system, immune and endocrine systems. Several of analytical methods for the analysis of BPA have been reported including electrochemical processes, chemical oxidation, ozonization, spectrophotometric, chromatographic techniques. Compared with other conventional analytical techniques, optic sensors are reliable, providing quick results, low cost, easy to use, stands out as a much more advantageous method because of the high precision and sensitivity. In this work, a new photocured polymeric fluorescence sensor was prepared and characterized for Bisphenol-A (BPA) analysis. Characterization of the membrane was carried out by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscope (SEM) techniques. The response characteristics of the sensor including dynamic range, pH effect and response time were systematically investigated. Acknowledgment: This work was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under Grant 115Y469.

Keywords: bisphenol-a, fluorescence, photopolymerization, polymeric sensor

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4648 A Study on the Factors Affecting Student Behavior Intention to Attend Robotics Courses at the Primary and Secondary School Levels

Authors: Jingwen Shan

Abstract:

In order to explore the key factors affecting the robot program learning intention of school students, this study takes the technology acceptance model as the theoretical basis and invites 167 students from Jiading District of Shanghai as the research subjects. In the robot course, the model of school students on their learning behavior is constructed. By verifying the causal path relationship between variables, it is concluded that teachers can enhance students’ perceptual usefulness to robotics courses by enhancing subjective norms, entertainment perception, and reducing technical anxiety, such as focusing on the gradual progress of programming and analyzing learner characteristics. Students can improve perceived ease of use by enhancing self-efficacy. At the same time, robot hardware designers can optimize in terms of entertainment and interactivity, which will directly or indirectly increase the learning intention of the robot course. By changing these factors, the learning behavior of primary and secondary school students can be more sustainable.

Keywords: TAM, learning behavior intentions, robot courses, primary and secondary school students

Procedia PDF Downloads 148
4647 Computational Fluid Dynamics Simulation of Floating Body Motion Interacting with Focused Waves

Authors: Seul-Ki Park, Jong-Chun Park, Gyu-Mok Jeon, Dae-Kyung Ock, Seung-Gyu Jeong

Abstract:

Rogue waves cause frequent accidents of ships and offshore structures, which can result in severe damage to the structures. The Rogue waves, which are also known as big waves, freak waves, extreme waves, monster waves, focused waves, giant waves and abnormal waves, are unexpected and suddenly appearing, and can have a breaking force to destroy the structure even though modern structures are designed to tolerate a breaking wave. In the present study, a series of focused waves are numerically reproduced by concentrating nonlinear multi-directional waves into a target point using a commercial CFD software, Star-CCM+. A flow analysis for investigating the physical characteristics of the focused waves is performed using the Star-CCM+, while it has several difficulties to examine the inner properties of the waves in existing potential theory and experiments. Additionally, the 6-DOF (Degree of Freedom) motion of a floating body interacting with the focused waves are simulated, and the dynamic response of the body are discussed.

Keywords: multidirectional waves, focused waves, rogue waves, wave-structure interaction, numerical wave tank, computational fluid dynamics

Procedia PDF Downloads 249
4646 Retrofitting of Bridge Piers against the Scour Damages: Case Study of the Marand-Soofian Route Bridge

Authors: Shatirah Akib, Hossein Basser, Hojat Karami, Afshin Jahangirzadeh

Abstract:

Bridge piers which are constructed in the track of high water rivers cause some variations in the flow patterns. This variation mostly is a result of the changes in river sections. Decreasing the river section, bridge piers significantly impress the flow patterns. Once the flow approaches the piers, the stream lines change their order, causing the appearance of different flow patterns around the bridge piers. New flow patterns are created following the geometry and the other technical characteristics of the piers. One of the most significant consequences of this event is the scour generated around the bridge piers which threatens the safety of the structure. In order to determine the properties of scour holes, to find maximum depth of the scour is an important factor. In this manuscript a numerical simulation of the scour around Marand-Soofian route bridge piers has been carried out via SSIIM 2.0 Software and the amount of maximum scour has been achieved subsequently. Eventually the methods for retrofitting of bridge piers against scours and also the methods for decreasing the amount of scour have been offered.

Keywords: scour, bridge pier, numerical simulation, SSIIM 2.0

Procedia PDF Downloads 464
4645 Comparison of Conventional Control and Robust Control on Double-Pipe Heat Exchanger

Authors: Hanan Rizk

Abstract:

A heat exchanger is a device used to mix liquids having different temperatures. In this case, the temperature control becomes a critical objective. This research work presents the temperature control of the double-pipe heat exchanger (multi-input multi-output (MIMO) system), which is modeled as first-order coupled hyperbolic partial differential equations (PDEs), using conventional and advanced control techniques and develops appropriate robust control strategy to meet stability requirements and performance objectives. We designed a PID controller and H-infinity controller for a heat exchanger (HE) system. Frequency characteristics of sensitivity functions and open-loop and closed-loop time responses are simulated using MATLAB software, and the stability of the system is analyzed using Kalman's test. The simulation results have demonstrated that the H-infinity controller is more efficient than PID in terms of robustness and performance.

Keywords: heat exchanger, multi-input multi-output system, MATLAB simulation, partial differential equations, PID controller, robust control

Procedia PDF Downloads 217
4644 Predicting COVID-19 Severity Using a Simple Parameters in Resource-Limited Settings

Authors: Sireethorn Nimitvilai, Ussanee Poolvivatchaikarn, Nuchanart Tomeun

Abstract:

Objective: To determine the simple laboratory parameters to predict disease severity among COVID-19 patients in resource-limited settings. Material and methods: A retrospective cohort study was conducted at Nakhonpathom Hospital, a 722-bed tertiary care hospital, with an average of 50,000 admissions per year, during April 15 and May 15, 2021. Eligible patients were adults aged ≥ 15 years who were hospitalized with COVID-19. Baseline characteristics, comorbid conditions ad laboratory findings at admission were collected. Predictive factors for severe COVID-19 infection were analyzed. Result: There were 207 patients (79 male and 128 female) and the mean age was 46.7 (16.8) years. Of these, 39 cases (18.8%) were severe and 168 (81.2%) cases were non-severe. Factors associated with severe COVID-19 were neutrophil to lymphocyte ratio ≥ 4 (OR 8.1, 95%CI 2.3-20.3, P < 0.001) and C-reactive protein to albumin ratio ≥ 10 (OR 3.49, 95%CI 1.3-9.1, p 0.01). Conclusions: Complete blood counts, C-reactive protein and albumin are simple, inexpensive, widely available tests and can be used to predict severe COVID-19 in resource-limited settings.

Keywords: COVID-19, predictor of severity, resource-limiting settings, simple laboratory parameters

Procedia PDF Downloads 177
4643 An Agent-Based Modelling Simulation Approach to Calculate Processing Delay of GEO Satellite Payload

Authors: V. Vicente E. Mujica, Gustavo Gonzalez

Abstract:

The global coverage of broadband multimedia and internet-based services in terrestrial-satellite networks demand particular interests for satellite providers in order to enhance services with low latencies and high signal quality to diverse users. In particular, the delay of on-board processing is an inherent source of latency in a satellite communication that sometimes is discarded for the end-to-end delay of the satellite link. The frame work for this paper includes modelling of an on-orbit satellite payload using an agent model that can reproduce the properties of processing delays. In essence, a comparison of different spatial interpolation methods is carried out to evaluate physical data obtained by an GEO satellite in order to define a discretization function for determining that delay. Furthermore, the performance of the proposed agent and the development of a delay discretization function are together validated by simulating an hybrid satellite and terrestrial network. Simulation results show high accuracy according to the characteristics of initial data points of processing delay for Ku bands.

Keywords: terrestrial-satellite networks, latency, on-orbit satellite payload, simulation

Procedia PDF Downloads 266
4642 Understanding New Zealand’s 19th Century Timber Churches: Techniques in Extracting and Applying Underlying Procedural Rules

Authors: Samuel McLennan, Tane Moleta, Andre Brown, Marc Aurel Schnabel

Abstract:

The development of Ecclesiastical buildings within New Zealand has produced some unique design characteristics that take influence from both international styles and local building methods. What this research looks at is how procedural modelling can be used to define such common characteristics and understand how they are shared and developed within different examples of a similar architectural style. This will be achieved through the creation of procedural digital reconstructions of the various timber Gothic Churches built during the 19th century in the city of Wellington, New Zealand. ‘Procedural modelling’ is a digital modelling technique that has been growing in popularity, particularly within the game and film industry, as well as other fields such as industrial design and architecture. Such a design method entails the creation of a parametric ‘ruleset’ that can be easily adjusted to produce many variations of geometry, rather than a single geometry as is typically found in traditional CAD software. Key precedents within this area of digital heritage includes work by Haegler, Müller, and Gool, Nicholas Webb and Andre Brown, and most notably Mark Burry. What these precedents all share is how the forms of the reconstructed architecture have been generated using computational rules and an understanding of the architects’ geometric reasoning. This is also true within this research as Gothic architecture makes use of only a select range of forms (such as the pointed arch) that can be accurately replicated using the same standard geometric techniques originally used by the architect. The methodology of this research involves firstly establishing a sample group of similar buildings, documenting the existing samples, researching any lost samples to find evidence such as architectural plans, photos, and written descriptions, and then culminating all the findings into a single 3D procedural asset within the software ‘Houdini’. The end result will be an adjustable digital model that contains all the architectural components of the sample group, such as the various naves, buttresses, and windows. These components can then be selected and arranged to create visualisations of the sample group. Because timber gothic churches in New Zealand share many details between designs, the created collection of architectural components can also be used to approximate similar designs not included in the sample group, such as designs found beyond the Wellington Region. This creates an initial library of architectural components that can be further expanded on to encapsulate as wide of a sample size as desired. Such a methodology greatly improves upon the efficiency and adjustability of digital modelling compared to current practices found in digital heritage reconstruction. It also gives greater accuracy to speculative design, as a lack of evidence for lost structures can be approximated using components from still existing or better-documented examples. This research will also bring attention to the cultural significance these types of buildings have within the local area, addressing the public’s general unawareness of architectural history that is identified in the Wellington based research ‘Moving Images in Digital Heritage’ by Serdar Aydin et al.

Keywords: digital forensics, digital heritage, gothic architecture, Houdini, procedural modelling

Procedia PDF Downloads 127
4641 Study of Mechanical Behavior of Unidirectional Composite Laminates According

Authors: Deliou Adel, Saadalah Younes, Belkaid Khmissi, Dehbi Meriem

Abstract:

Composite materials, in the most common sense of the term, are a set of synthetic materials designed and used mainly for structural applications; the mechanical function is dominant. The mechanical behaviors of the composite, as well as the degradation mechanisms leading to its rupture, depend on the nature of the constituents and on the architecture of the fiber preform. The profile is required because it guides the engineer in designing structures with precise properties in relation to the needs. This work is about studying the mechanical behavior of unidirectional composite laminates according to different failure criteria. Varying strength parameter values make it possible to compare the ultimate mechanical characteristics obtained by the criteria of Tsai-Hill, Fisher and maximum stress. The laminate is subjected to uniaxial tensile membrane forces. Estimates of their ultimate strengths and the plotting of the failure envelope constitute the principal axis of this study. Using the theory of maximum stress, we can determine the various modes of damage of the composite. The different components of the deformation are presented for different orientations of fibers.

Keywords: unidirectional kevlar/epoxy composite, failure criterion, membrane stress, deformations, failure envelope

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4640 Simulation of Turboexpander Potential in a City Gate Station under Variations of Feed Characteristic

Authors: Tarannom Parhizkar, Halle Bakhteeyar

Abstract:

This paper presents a feasibility assessment of an expansion system applied to the natural gas transportation process in Iran. Power can be generated from the pressure energy of natural gas along its supply chain at various pressure reduction points by using turboexpanders. This technology is being applied in different countries around the world. The system consists of a turboexpander reducing the natural gas pressure and providing mechanical energy to drive electric generator. Moreover, gas pre-heating, required to prevent hydrate formation, is performed upstream of expansion stage using burner. The city gate station (CGS) has a nominal flow rate in range of 45000 to 270000 cubic meters per hour and a pressure reduction from maximum 62 bar at the upstream to 6 bar. Due to variable feed pressure and temperature in this station sensitivity analysis of generated electricity and required heat is performed. Results show that plant gain is more sensible to pressure variation than temperature changes. Furthermore, using turboexpander to reduce the pressure result in an electrical generation of 2757 to 17574 kW with the value of approximately 4 million US$ per year. Moreover, the required heat range to prevent a hydrate formation is almost 2189 to 14157 kW. To provide this heat, a burner is used with a maximum annual cost of 268,640 $ burner fuel. Therefore, the actual annual benefit of proposed plant modification is approximately over 6,5 million US$.

Keywords: feasibility study, simulation, turboexpander, feed characteristic

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4639 Proportion and Factors Associated with Presumptive Tuberculosis among Suspected Pediatric Tuberculosis Patients

Authors: Naima Nur, Safa Islam, Saeema Islam, Md. Faridul Alam

Abstract:

Background: The worldwide increase in pediatric presumptive tuberculosis (TB) is the most life-threatening challenge in effectively controlling TB. The objective of this study was to determine the proportion of presumptive TB and the factors associated with it. Methods: A cross-sectional study was conducted between March and November 2013 at ICDDR-Bangladesh. Two hundred twelve pulmonary and extra-pulmonary specimens were collected from 84 suspected pediatric patients diagnosed with TB based on their clinical symptoms/radiological findings. Presumptive TB and confirmed TB were considered presumptive TB and non-presumptive TB and were isolated by smear-microscopy, culture, and GeneXpert. Logistic regression was used to analyze associations between outcome and predictor variables. Results: The proportion of presumptive TB was 85.7%, and 14.3% of non-presumptive TB. In presumptive TB, vaccine scars, family TB history, and school-going children were 16.6%, 33.3%, and 56.9%, respectively. In contrast, vaccine scars and family TB history were 8.3%, and school-going children were 58.3% in non-presumptive TB. Significant factors did not appear in the logistic regression analysis. Conclusion: Despite the high proportion of presumptive TB, there was no statistically significant between presumptive TB and non-presumptive TB.

Keywords: presumptive tuberculosis, confirmed tuberculosis, patient's characteristics, diagnosis

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4638 Ab Initio Calculations of Structure and Elastic Properties of BexZn1−xO Alloys

Authors: S. Lakel, F. Elhamra, M. Ibrir, K. Almi

Abstract:

There is a growing interest in Zn1-xBexO (ZBO)/ZnO hetero structures and quantum wells since the band gap energy of Zn1-xBexO solid solutions can be turned over a very large range (3.37–10.6 eV) as a function of the Be composition. ZBO/ZnO has been utilized in ultraviolet light emission diodes and lasers, and may find applications as active elements of various other electronic and optoelectronic devices. Band gap engineering by Be substitution enables the facile preparation of barrier layers and quantum wells in device structures. In addition, ZnO and its ternary alloys, as piezoelectric semiconductors, have been used for high-frequency surface acoustic wave devices in wireless communication systems due to their high acoustic velocities and large electromechanical coupling. However, many important parameters such as elastic constants, bulk modulus, Young’s modulus and band-gap bowing. First-principles calculations of the structural, electrical and elastic properties of Zn1-xBexO as a function of the Be concentration x have been performed within density functional theory using norm-conserving pseudopotentials and local density approximation (LDA) for the exchange and correlation energy. The alloys’ lattice constants may deviate from the Vegard law. As Be concentration increases, the elastic constants, the bulk modulus and Young’s modulus of the alloys increase, the band gap increases with increasing Be concentration and Zn1-xBexO alloys have direct band. Our calculated results are in good agreement with experimental data and other theoretical calculations.

Keywords: DFT calculation, norm-conserving pseudopotentials, ZnBeO alloys, ZnO

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4637 Rubber Wood as a Potential Biomass Feedstock for Biochar via Slow Pyrolysis

Authors: Adilah Shariff, Radin Hakim, Nurhayati Abdullah

Abstract:

Utilisation of biomass feedstock for biochar has received increasing attention because of their potential for carbon sequestration and soil amendment. The aim of this study is to investigate the characteristics of rubber wood as a biomass feedstock for biochar via slow pyrolysis process. This was achieved by using proximate, ultimate, and thermogravimetric analysis (TGA) as well as heating value, pH and lignocellulosic determination. Rubber wood contains 4.13 mf wt.% moisture, 86.30 mf wt.% volatile matter, 0.60 mf wt.% ash content, and 13.10 mf wt.% fixed carbon. The ultimate analysis shows that rubber wood consists of 44.33 mf wt.% carbon, 6.26 mf wt.% hydrogen, 19.31 mf wt.% nitrogen, 0.31 mf wt.% sulphur, and 29.79 mf wt.% oxygen. The higher heating value of rubber wood is 22.5 MJ/kg, and its lower heating value is 21.2 MJ/kg. At 27 °C, the pH value of rubber wood is 6.83 which is acidic. The lignocellulosic analysis revealed that rubber wood composition consists of 2.63 mf wt.% lignin, 20.13 mf wt.% cellulose, and 65.04 mf wt.% hemicellulose. The volatile matter to fixed carbon ratio is 6.58. This led to a biochar yield of 25.14 wt.% at 500 °C. Rubber wood is an environmental friendly feedstock due to its low sulphur content. Rubber wood therefore is a suitable and a potential feedstock for biochar production via slow pyrolysis.

Keywords: biochar, biomass, rubber wood, slow pyrolysis

Procedia PDF Downloads 314
4636 Study of Aqueous Solutions: A Dielectric Spectroscopy Approach

Authors: Kumbharkhane Ashok

Abstract:

The time domain dielectric relaxation spectroscopy (TDRS) probes the interaction of a macroscopic sample with a time-dependent electrical field. The resulting complex permittivity spectrum, characterizes amplitude (voltage) and time scale of the charge-density fluctuations within the sample. These fluctuations may arise from the reorientation of the permanent dipole moments of individual molecules or from the rotation of dipolar moieties in flexible molecules, like polymers. The time scale of these fluctuations depends on the sample and its relative relaxation mechanism. Relaxation times range from some picoseconds in low viscosity liquids to hours in glasses, Therefore the DRS technique covers an extensive dynamical process, its corresponding frequency range from 10-4 Hz to 1012 Hz. This inherent ability to monitor the cooperative motion of molecular ensemble distinguishes dielectric relaxation from methods like NMR or Raman spectroscopy which yield information on the motions of individual molecules. An experimental set up for Time Domain Reflectometry (TDR) technique from 10 MHz to 30 GHz has been developed for the aqueous solutions. This technique has been very simple and covers a wide band of frequencies in the single measurement. Dielectric Relaxation Spectroscopy is especially sensitive to intermolecular interactions. The complex permittivity spectra of aqueous solutions have been fitted using Cole-Davidson (CD) model to determine static dielectric constants and relaxation times for entire concentrations. The heterogeneous molecular interactions in aqueous solutions have been discussed through Kirkwood correlation factor and excess properties.

Keywords: liquid, aqueous solutions, time domain reflectometry

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4635 A Neural Network Modelling Approach for Predicting Permeability from Well Logs Data

Authors: Chico Horacio Jose Sambo

Abstract:

Recently neural network has gained popularity when come to solve complex nonlinear problems. Permeability is one of fundamental reservoir characteristics system that are anisotropic distributed and non-linear manner. For this reason, permeability prediction from well log data is well suited by using neural networks and other computer-based techniques. The main goal of this paper is to predict reservoir permeability from well logs data by using neural network approach. A multi-layered perceptron trained by back propagation algorithm was used to build the predictive model. The performance of the model on net results was measured by correlation coefficient. The correlation coefficient from testing, training, validation and all data sets was evaluated. The results show that neural network was capable of reproducing permeability with accuracy in all cases, so that the calculated correlation coefficients for training, testing and validation permeability were 0.96273, 0.89991 and 0.87858, respectively. The generalization of the results to other field can be made after examining new data, and a regional study might be possible to study reservoir properties with cheap and very fast constructed models.

Keywords: neural network, permeability, multilayer perceptron, well log

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4634 Structured Tariff Calculation to Promote Geothermal for Energy Security

Authors: Siti Mariani, Arwin DW Sumari, Retno Gumilang Dewi

Abstract:

This paper analyzes the necessity of a structured tariff calculation for geothermal electricity in Indonesia. Indonesia is blessed with abundant natural resources and a choices of energy resources to generate electricity among other are coal, gas, biomass, hydro to geothermal, creating a fierce competition in electricity tariffs. While geothermal is inline with energy security principle and green growth initiative, it requires a huge capital funding. Geothermal electricity development consists of phases of project with each having its own financial characteristics. The Indonesian government has set a support in the form of ceiling price of geothermal electricity tariff by 11 U.S cents / kWh. However, the government did not set a levelized cost of geothermal, as an indication of lower limit capacity class, to which support is given. The government should establish a levelized cost of geothermal energy to reflect its financial capability in supporting geothermal development. Aside of that, the government is also need to establish a structured tariff calculation to reflect a fair and transparent business cooperation.

Keywords: load fator, levelized cost of geothermal, geothermal power plant, structured tariff calculation

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4633 Effect of Bulk Density and Fiber Blend Content of Nonwoven Textiles on Flammability Properties

Authors: Klara Masnicova, Jiri Chaloupek

Abstract:

Flammability plays an important role in applications such as thermal and acoustic insulation and other technical nonwoven textiles. The study was conducted in an attempt to investigate the flammability behavior of nonwoven textiles in relation to their structural and material characteristics, with emphasis given to the blending ratios of flammable and non-flammable fibers or fibers with reduced flammability. Nonwoven structures made of blends of viscose/oxidized polyacrylonitrile (VS/oxidized PAN fibers and polyethylene terephthalate/oxidized polyacrylonitrile (PET/oxidized PAN) fibers in several bulk densities are evaluated. The VS/oxidized PAN blend is model material. The flammability was studied using a cone calorimeter. Reaction to fire was observed using the small flame test method. Interestingly, the results show some of the blending ratios do not react to the heat in linear response to bulk density. This outcome can have a huge impact on future product development in fire safety and for the general understanding of flammability behavior of nonwovens made of staple fibers.

Keywords: bulk density, cone calorimetry, flammability, nonwoven textiles

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4632 Unsteady Characteristics Investigation on the Precessing Vortex Breakdown and Energy Separation in a Vortex Tube

Authors: Xiangji Guo, Bo Zhang

Abstract:

In this paper, the phenomenon of vortex breakdown in a vortex tube was analyzed within the scope of unsteady character in swirl flows. A 3-D Unsteady Reynolds-averaged Navier–Stokes (URANS) closed by the Reynolds Stress Model (RSM) was adopted to simulate the large-scale vortex structure in vortex tube, and the numerical model was verified by the steady results. The swirl number was calculated for the vortex tube and the flow field was classed as strong swirl flow. According to the results, a time-dependent spiral flow field gyrates around a central recirculation zone which is precessing around the axis of the tube, and manifests the flow structure is the spiral type (S-type) vortex breakdown. The vortex breakdown is crucial for the formation of the central recirculation zone (CRZ), a further discussion was about the affection on CRZ with the different external conditions of vortex tube, the study on the unsteady characters was expected to hope to design of vortex tube and analyze the energy separation effect.

Keywords: vortex tube, vortex breakdown, central recirculation zone, unsteady, energy separation

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4631 Optimality Theoretic Account of Indian Loanwords in Hadhrami Arabic

Authors: Mohammed Saleh Lahmdi, Hassan Obeid Alfadly

Abstract:

This study explores an optimality-theoretic account of Indian loanwords in Hadhrami Arabic (henceforth HA), a variety of Arabic spoken in Hadhramout Province in the coastal areas and Hadhramout Valley. The purpose of this paper is to find out how the phonological forms of Indian loanwords can be accounted for from an OT standpoint. To achieve this purpose, two main instruments were implemented: participant observation and interview. The sample of this study was selected carefully with certain characteristics by judgment sampling consisting of eleven informants. An ethnographic qualitative approach was employed to find out the phonological articulations that the researcher encountered during the implementation. Many phonological processes are used and several markedness and faithfulness constraints have been interacted in conflict in order to choose the optimal form of Hadhrami realisations. The findings of the study confirm that the Hadhrami syllable structure prevails over the donor language, i.e., the Indian (mainly Urdu) language. Specifically, markedness constraints dominate faithfulness ones when most of the Indian loanwords are incorporated into HA.

Keywords: linguistic borrowing, optimality theory, Hadhrami Arabic, loanword, phonological processes

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4630 Utilization of Mango (Mangifera Indica) Seeds as an Organic Liquid Fertilizer in Bok-Choy (Brassica Rapa)

Authors: Bryan Emmanuel B. Marcelo, Frances Laura C. Galvez, Cyra Aleera T. Asanza, Ava Venice P. Garin

Abstract:

The present study experimented with the utilization of mango (Mangifera indica) seeds as a fertilizer in the hydroponic farming of Bok Choy. The seeds were dried, mixed with EM Bokashi, and fermented for 14 days. The solution was then diluted into several ratios or concentrations: 25%: 1 part mango seed solution, 3 parts water; 50%: 2 parts mango seed solution, 2 parts water; 75%: 3 parts mango seed solution, 1 part water. 5 cups of soil with Bok Choy seeds were each planted in different containers for different concentrations of fertilizer. The fermentation of the nutrient solution lasted exactly 14 days and was directly brought to the lab for nutrient analysis and testing. In the data presented by the researchers in a span of 14 days, the study assessed varied mango seed fertilizer concentrations on Bok Choy growth. Despite an acidic pH (4.19) and moderate electrical conductivity, the 75% concentration yielded the highest growth (2.1cm) over 14 days, followed by 50%, 0, and 25%. Leaf count was consistently highest at 75%, and the leaf color remained #8CAA50 across concentrations. This emphasizes the importance of precise fertilizer application, with the 75% concentration showing optimal growth, the highest leaf count, and prevention of leaf withering until Day 14. Overall, these findings contribute to understanding bok choy’s adaptability and responses to different nutrient conditions.

Keywords: dilution ratios, organic liquid fertilizer, hydroponic farming, growth asssessment

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