Search results for: insertion force

Authors: Francisco J. Ortega, Claudia Roman, Moisés García-Morales, Francisco J. Navarro

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Asphaltic bitumen has been largely used in both industrial and civil engineering, mostly in pavement construction and roofing membrane manufacture. However, bitumen as such is greatly susceptible to temperature variations, and dramatically changes its in-service behavior from a viscoelastic liquid, at medium-high temperatures, to a brittle solid at low temperatures. Bitumen modification prevents these problems and imparts improved performance. Isocyanates like polymeric MDI (mixture of 4,4′-diphenylmethane di-isocyanate, 2,4’ and 2,2’ isomers, and higher homologues) have shown to remarkably enhance bitumen properties at the highest in-service temperatures expected. This comes from the reaction between the –NCO pendant groups of the oligomer and the most polar groups of asphaltenes and resins in bitumen. In addition, oxygen diffusion and/or UV radiation may provoke bitumen hardening and ageing. With the purpose of minimizing these effects, nano-layered-silicates (nanoclays) are increasingly being added to bitumen formulations. Montmorillonites, a type of naturally occurring mineral, may produce a nanometer scale dispersion which improves bitumen thermal, mechanical and barrier properties. In order to increase their lipophilicity, these nanoclays are normally treated so that organic cations substitute the inorganic cations located in their intergallery spacing. In the present work, the combined effect of polymeric MDI and the commercial montmorillonite Cloisite® 20A was evaluated. A selected bitumen with penetration within the range 160/220 was modified with 10 wt.% Cloisite® 20A and 2 wt.% polymeric MDI, and the resulting ternary composites were characterized by linear rheology, X-ray diffraction (XRD) and Atomic Force Microscopy (AFM). The rheological tests evidenced a notable solid-like behavior at the highest temperatures studied when bitumen was just loaded with 10 wt.% Cloisite® 20A and high-shear blended for 20 minutes. However, if polymeric MDI was involved, the sequence of addition exerted a decisive control on the linear rheology of the final ternary composites. Hence, in bitumen/Cloisite® 20A/polymeric MDI formulations, the previous solid-like behavior disappeared. By contrast, an inversion in the order of addition (bitumen/polymeric MDI/ Cloisite® 20A) enhanced further the solid-like behavior imparted by the nanoclay. In order to gain a better understanding of the factors that govern the linear rheology of these ternary composites, a morphological and microstructural characterization based on XRD and AFM was conducted. XRD demonstrated the existence of clay stacks intercalated by bitumen molecules to some degree. However, the XRD technique cannot provide detailed information on the extent of nanoclay delamination, unless the entire fraction has effectively been fully delaminated (situation in which no peak is observed). Furthermore, XRD was unable to provide precise knowledge neither about the spatial distribution of the intercalated/exfoliated platelets nor about the presence of other structures at larger length scales. In contrast, AFM proved its power at providing conclusive information on the morphology of the composites at the nanometer scale and at revealing the structural modification that yielded the rheological properties observed. It was concluded that high-shear blending brought about a nanoclay-reinforced network. As for the bitumen/Cloisite® 20A/polymeric MDI formulations, the solid-like behavior was destroyed as a result of the agglomeration of the nanoclay platelets promoted by chemical reactions.

Keywords: Atomic Force Microscopy, bitumen, composite, isocyanate, montmorillonite.

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Authors: M. A. Deyab

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The effect of zwitterionic surfactant (ZS) on erosion-corrosion of API X52 steel in oil sands slurry was studied using Tafel polarization and anodic polarization measurements. The surface morphology of API X52 steel was examined with scanning electron microscopy (SEM) and atomic force microscopy (AFM). ZS inhibited the erosion-corrosion of API X52 steel in oil sands' slurry, and the inhibition efficiency increased with increasing ZS concentration but decreased with increasing temperature. Polarization curves indicate that ZS act as a mixed type of inhibitor. Inhibition efficiencies of ZS in the dynamic condition are not as effective as that obtained in the static condition.

Keywords: corrosion, surfactant, oil sands slurry, erosion-corrosion

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Authors: Elisa Maître

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The redeployment of tram networks in French cities has considerably modified public spaces and the way citizens use them. Above and beyond the image that trams have of contributing to the sustainable urban development, the question of safety for users in these spaces has not been studied much. This study is based on an analysis of use of public spaces laid out for trams, from the standpoint of legibility and safety concerns. The study also examines to what extent the complexity of the design process, with many interactions between numerous and varied players in this process has a role in the genesis of these problems. This work is mainly based on the analysis of links between the uses of these re-designed public spaces (through observations, interviews of users and accident studies) and the analysis of the design conditions and processes of the projects studied (mainly based on interviews with the actors of these projects). Practical analyses were based three points of view: that of the planner, that of the user (based on observations and interviews) and that of the road safety expert. The cities of Montpellier, Marseille and Nice are the three fields of study on which the demonstration of this thesis is based. On part, the results of this study allow showing that the insertion of tram poses some problems complication of public areas of French cities. These complications related to the restructuring of public spaces for the tram, create difficulties of use and safety concerns. On the other hand, interviews depth analyses, fully transcribed, have led us to develop particular dysfunction scenarios in the design process. These elements lead to question the way the legibility and safety of these new forms of public spaces are taken into account. Then, an in-depth analysis of the design processes of public spaces with trams systems would also be a way of better understanding the choices made, the compromises accepted, and the conflicts and constraints at work, weighing on the layout of these spaces. The results presented concerning the impact that spaces laid out for trams have on the difficulty of use, suggest different possibilities for improving the way in which safety for all users is taken into account in designing public spaces.

Keywords: public spaces, road layout, users, design process of urban projects

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Authors: Ahmed Hamza Yache

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The main purpose of this study is to estimate the distribution of shear forces in building structures with asymmetries in the plan submitted to seismic forces can cause, in this case, simultaneous deformations of translation and torsion. To this end, the distribution of shear forces is obtained by seismic forces calculated from the equivalent static method of the Algerian earthquake code RPA 99 (2003 version) and spectral modal analysis for an irregular building plan without kinks. Comparison of the results obtained by these two methods used to highlight the difference in terms of distributions of shear forces in such structures.

Keywords: structure, irregular, code, seismic, method, force, period

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Authors: Ouassila Bekkal Brikci Benhabib, Zahia Boucherit Otmani, Kebir Boucherit, A. Seghir

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The establishment of intravenous catheters in hospitalized patient is an act common in many clinical situations. These therapeutic tools, from their insertion in the body, represent gateways including fungal germs prone. The latter can generate the growth of biofilms, which can be the cause of fungal infection. Faced with this problem, we conducted a study at the University Hospital of Tlemcen in the neurosurgery unit and aims to isolate and identify Candida yeasts from intravenous catheters. Then test their ability to form biofilms. Materials and methods: 256 patient hospitalized in surgery of the hospital in west Algeria were submitted to this study. All samples were taken from peripheral venous catheters implanted for 72 hours or more days. A total of 31 isolates of Candida species were isolated. MIC and SMIC are determined at 80% inhibition by the test XTT tetrazolium measured at 490 nm. The final concentrations of antifungal agent being between 0.03 and 16 mg / ml for amphotericin B and from 0.015 to 8 mg / mL caspofungin. Results: 31 Candida species isolates from catheters including 14 Candida albicans and 17 Candida non albicans . 21 strains of all the isolates were able to form biofilms. In their form of Planktonic cells, all isolates are 100% susceptible to antifungal agents tested. However, in their state of biofilms, more isolates have become tolerant to the tested antifungals. Conclusion: Candida yeasts isolated from intravascular catheters are considered an important virulence factor in the pathogenesis of infections. Their involvement in catheter-related infections can be disastrous for their potential to generate biofilms. They survive high concentrations of antifungal where treatment failure. Pending the development of a therapeutic approach antibiofilm related to catheters, their mastery is going through: -The risk of infection prevention based on the training and awareness of medical staff, -Strict hygiene and maximum asepsis, and -The choice of material limiting microbial colonization.

Keywords: candida, biofilm, hospital, infection, amphotericin B, caspofungin

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Authors: Xiaobo Rui, Zhoumo Zeng, Yibo Li

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A novel tri-cantilever energy harvester with magnetic oscillator was presented, which could convert the ambient vibration into electrical energy to power the low-power devices such as wireless sensor networks. The most common way to harvest vibration energy is based on the use of linear resonant devices such as cantilever beam, since this structure creates the highest strain for a given force. The highest efficiency will be achieved when the resonance frequency of the harvester matches the vibration frequency. The limitation of the structure is the narrow effective bandwidth. To overcome this limitation, this article introduces a broadband tri-cantilever harvester with nonlinear stiffness. This energy harvester typically consists of three thin cantilever beams vertically arranged with Neodymium Magnets ( NdFeB)magnetics at its free end and a fixed base at the other end. The three cantilevers have different resonant frequencies by designed in different thicknesses. It is obviously that a similar advantage of multiple resonant frequencies as piezoelectric cantilevers array structure is built. To achieve broadband energy harvesting, magnetic interaction is used to introduce the nonlinear system stiffness to tune the resonant frequency to match the excitation. Since the three cantilever tips are all free and the magnetic force is distance dependent, the resonant frequencies will be complexly changed with the vertical vibration of the free end. Both model and experiment are built. The electromechanically coupled lumped-parameter model is presented. An electromechanical formulation and analytical expressions for the coupled nonlinear vibration response and voltage response are given. The entire structure is fabricated and mechanically attached to a electromagnetic shaker as a vibrating body via the fixed base, in order to couple the vibrations to the cantilever. The cantilevers are bonded with piezoelectric macro-fiber composite (MFC) materials (Model: M8514P2). The size of the cantilevers is 120*20mm2 and the thicknesses are separately 1mm, 0.8mm, 0.6mm. The prototype generator has a measured performance of 160.98 mW effective electrical power and 7.93 DC output voltage via the excitation level of 10m/s2. The 130% increase in the operating bandwidth is achieved. This device is promising to support low-power devices, peer-to-peer wireless nodes, and small-scale wireless sensor networks in ambient vibration environment.

Keywords: tri-cantilever, ambient vibration, energy harvesting, magnetic oscillator

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Authors: L. S. Supian, Mohd Syuhaimi Ab-Rahman, Norhana Arsad

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Experimental study has been done to study the performance on polymer optical fiber splitter characterization when different bending radii are applied on splitters with different fiber cores. The splitters with different cores pair are attached successively to splitter platform of ellipse-shape geometrical blocks of several bending radii. A force is exerted upon the blocks thus the splitter in order to encourage the splitting of energy between the two fibers. The aim of this study is to investigate which fiber core pair gives the optimum performance that goes with each bending radius in order to develop an effective splitter.

Keywords: splitter, macro-bending, cores, geometrical blocks

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Authors: Brahim Fersadou, Henda Kahalerras

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This work deals with the problem of MHD mixed convection in a completely porous and differentially heated vertical channel. The model of Darcy-Brinkman-Forchheimer with the Boussinesq approximation is adopted and the governing equations are solved by the finite volume method. The effects of magnetic field and buoyancy force intensities are given by the Hartmann and Richardson numbers respectively, as well as the Joule heating represented by Eckert number on the velocity and temperature fields, are examined. The main results show an augmentation of heat transfer rate with the decrease of Darcy number and the increase of Ri and Ha when Joule heating is neglected.

Keywords: heat sources, magnetic field, mixed convection, porous channel

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Authors: Umesh Kumar Soni, Suresh Kumar Soni, S. R. Awasthi

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Worldwide biggest difficulties are climate change, future availability of fossil fuels, and economical feasibility of renewable energy. They force us to use to a greater extent renewable energy and develop suitable hybrid renewable systems. Building heating/cooling consumes significant amount of energy. It can be conserved by use of proper heating/cooling techniques. This paper reviews and critically analyzes various active, passive and hybrid heating/cooling techniques used in green buildings.

Keywords: natural ventilation, energy conservation, hybrid ventilation techniques, climate change

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Authors: Florian Kiebert, Hagen Schmidt

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Standing surface acoustic waves (sSAWs) have already been used to manipulate particles in a microfluidic channel made of polydimethylsiloxan (PDMS). Usually two identical facing interdigital transducers (IDTs) are exploited to form an sSAW. Further, it has been reported that an sSAW can be generated by a single IDT using a superstrate resonating cavity or a PDMS post. Nevertheless, both setups utilising a traveling surface acoustic wave (tSAW) to create an sSAW for particle manipulation are costly. We present a simplified setup with a tSAW and a PDMS channel to form an sSAW. The incident tSAW is reflected at the rear PDMS channel wall and superimposed with the reflected tSAW. This superpositioned waves generates an sSAW but only at regions where the distance to the rear channel wall is smaller as the attenuation length of the tSAW minus the channel width. Therefore in a channel of 500µm width a tSAW with a wavelength λ = 120 µm causes a sSAW over the whole channel, whereas a tSAW with λ = 60 µm only forms an sSAW next to the rear wall of the channel, taken into account the attenuation length of a tSAW in water. Hence, it is possible to concentrate and trap particles in a defined region of the channel by adjusting the relation between the channel width and tSAW wavelength. Moreover, it is possible to generate a particle gradient over the channel width by picking the right ratio between channel wall and wavelength. The particles are moved towards the rear wall by the acoustic streaming force (ASF) and the acoustic radiation force (ARF) caused by the tSAW generated bulk acoustic wave (BAW). At regions in the channel were the sSAW is dominating the ARF focuses the particles in the pressure nodes formed by the sSAW caused BAW. On the one side the ARF generated by the sSAW traps the particle at the center of the tSAW beam, i. e. of the IDT aperture. On the other side, the ASF leads to two vortices, one on the left and on the right side of the focus region, deflecting the particles out of it. Through variation of the applied power it is possible to vary the number of particles trapped in the focus points, because near to the rear wall the amplitude of the reflected tSAW is higher and, therefore, the ARF of the sSAW is stronger. So in the vicinity of the rear wall the concentration of particles is higher but decreases with increasing distance to the wall, forming a gradient of particles. The particle gradient depends on the applied power as well as on the flow rate. Thus by variation of these two parameters it is possible to change the particle gradient. Furthermore, we show that the particle gradient can be modified by changing the relation between the channel width and tSAW wavelength. Concluding a single IDT generates an sSAW in a PDMS microchannel enables particle gradient generation in a well-defined microfluidic flow system utilising the ARF and ASF of a tSAW and an sSAW.

Keywords: ARF, ASF, particle manipulation, sSAW, tSAW

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Authors: Matthew Lee Turnbough

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In 2007 Spain began to experience the effects of a deep economic crisis, which would generate a situation characterised by instability and uncertainty. This has been an obstacle, especially acute for the youth of this country seeking to enter the workforce. As a result of the impact of COVID-19, the youth in Spain are now suffering the effects of a new crisis that has deepened an already fragile labour environment. In this paper, we analyse the discourses that have emerged from a precarious labour market, specifically from two companies dedicated to operating job portals and job listings in Spain, Job Today, and CornerJob. These two start-up businesses have developed mobile applications geared towards young adults in search of employment in the service sector, two of the companies with the highest user rates in Spain. Utilizing a discourse analysis approach, we explore the impact of individualization and how the process of psychologization may contribute to an increasing reliance on individual solutions to social problems. As such, we seek to highlight the expectations and demands that are placed upon young workers and the type of subjectivity that this dynamic could foster, all this within an unstable framework seemingly marked by chance, a context which is key for the emergence of individualization. Furthermore, we consider the extent to which young adults incorporate these discourses and the strategies they employ basing our analysis on the VULSOCU (New Forms of Socio-Existential Vulnerability, Supports, and Care in Spain) research project, specifically the results of nineteen in-depth interviews and three discussion groups with young adults in this country. Consequently, we seek to elucidate the argumentative threads rooted in the process of individualization and underline the implications of this dynamic for the young worker and his/her labour insertion while also identifying manifestations of the goddess of fortune as a representation of chance in this context. Finally, we approach this panorama of social change in Spain from the perspective of the individuals or young adults who find themselves immersed in this transition from one crisis to another.

Keywords: chance, crisis, discourses, individualization, work, youth

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Authors: Sabine Ambros, Ulrich Kulozik

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Berries such as blue- and raspberries belong to the most valuable fruits. To preserve the characteristic flavor and the high contents of vitamins and anthocyanins, the very sensitive berries are usually dried by lyophilization. As this method is very time- and energy-consuming, the dried fruit is extremely expensive. However, healthy snack foods are growing in popularity. Especially dried fruit free of any additives or additional sugar are more and more asked for. To make these products affordable, the fruits have to be dried by a method that is more energy-efficient than freeze drying but reveals the same high product quality. The additional insertion of microwaves to a freeze drying process was examined in this work to overcome the inconveniences of freeze drying. As microwaves penetrate the product volumetrically, sublimation takes place simultaneously all over the product and leads to a many times shorter process duration. A range of microwave and pressure settings was applied to find the optimum drying condition. The influence of the process parameters microwave power and chamber pressure on drying kinetics, product temperature and product quality was investigated to find the best condition for an energy-efficient process with high product quality. The product quality was evaluated by rehydration capacitiy, crispiness, shrinkage, color, vitamin C content and antioxidative capacity. The conclusion could be drawn that microwave freeze dried berries were almost equal to freeze dried fruit in all measured quality parameters or even could overcome it. Additionally, sensory evaluations could confirm the analytical studies. Drying time could be reduced by more than 75% at much lower energy consumption rates. Thus, an energy-efficient and cost saving method compared to the conventional freeze drying technique for the gentle production of tasty fruit or vegetable snacks has been found. This technique will make dried high-quality snacks available for many of consumers.

Keywords: blueberries, freeze drying, microwave freeze drying, process parameters, product quality

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Authors: Mohammad Zakir, Saamia Shams

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Background: Provision of quality family planning services remarkably contribute towards increased uptake of modern contraceptive methods and have important implications on reducing fertility rates. The quality of care in family planning has beneficial impact on reproductive health of women, yet little empirical evidence is present to show the relationship between the impact of adequate training of Community Mid Wives (CMW) and quality family planning services. Aim: This study aimed to enhance the knowledge and counseling skills of CMWs in improving the access to quality client-centered family planning services in Pakistan. Methodology: A quasi-experimental longitudinal study using Initial Quality Assurance Scores-Training-Post Training Quality Assurance Scores design with a non- equivalent control group was adopted to compare a set of experimental CMWs that received four days training package including Family Planning Methods, Counselling, Communication skills and Practical training on IUCD insertion with a set of comparison CMWs that did not receive any intervention. A sample size of 100 CMW from Suraj Social Franchise (SSF) private providers was recruited from both urban and rural Pakistan. Results: Significant improvement in the family planning knowledge and counseling skills (p< 0.001) of the CMWs was evident in the experimental group as compared to comparison group with p > 0.05. Non- significant association between pre-test level family planning knowledge and counseling skills was observed in both the groups (p>0.05). Conclusion: The findings demonstrate that adequate training is an important determinant of quality of family planning services received by clients. Provider level training increases the likelihood of contraceptives uptake and decreases the likelihood of both unintended and unwanted pregnancies. Enhancing quality of family planning services may significantly help reduce the fertility and improve the reproductive health indicators of women in Pakistan.

Keywords: community mid wives, family planning services, quality of care, training

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Authors: Ali Mausmi, Ahmed Abbou, Rachid El Akhrif

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This research paper aims to reduce the chattering phenomenon due to control by sliding mode control applied on a wind energy conversion system based on the doubly fed induction generator (DFIG). Our goal is to offset the effect of parametric uncertainties and come as close as possible to the dynamic response solicited by the control law in the ideal case and therefore force the active and reactive power generated by the DFIG to accurately follow the reference values which are provided to it. The simulation results using Matlab / Simulink demonstrate the efficiency and performance of the proposed technique while maintaining the simplicity of control by first order sliding mode.

Keywords: control of speed, correction of the equivalent command, induction generator, sliding mode

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Authors: Yun-Chin Chung, Nileema Divate, Gen-Hung Chen, Pei-Ru Huang, Rupesh Divate

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Many environmental factors, such as glucose concentration, ethanol, temperature, osmotic pressure and pH, decrease the production rate of ethanol using yeast as a starter. Fermentation starters with high tolerance to various stresses are always demanded for brewing industry. Trehalose, a storage carbohydrate in cell wall of yeast, plays an important role in tolerance of environmental stress by preserving integrity of plasma membrane and stabilizing proteins. Furan aldehydes are toxic to yeast and the growth rate of yeast is significantly reduced if furan aldehydes were present in the fermentation medium. In yeast, aldehyde reductase is involved in the detoxification of reactive aldehydes and consequently the growth of yeast is improved. The aims of this study were to construct a genetic recombinant Saccharomyces cerevisiae or Pichia pastoris with furfural and HMF degrading and high ethanol tolerance capacities. Yeast strains were engineered by genetic recombination for overexpression of trehalose-6-phosphate synthase gene (tps1) and aldehyde reductase gene (ari1). TPS1 gene was cloned from S. cerevisiae by reverse transcription-polymerase chain reaction (RT-PCR) and then ligated with pGAPZαC vector. The constructed vector, pGAPZC-tps1, was transformed to recombinant yeasts strain with overexpression of ari1. The transformants with pGAPZC-tps1-ari1 were generated called STA (S. cerevisiae) and PTA (P. pastoris) with overexpression of tps1, ari1. PCR with tps1-specific primers and western blot with his-tag confirmed the gene insertion and protein expression of tps1 in the transformants, respectively. The neutral trehalase gene (nth1) of STA was successfully deleted and the novel strain STAΔN will be used for further study, including the measurement of trehalose concentration and ethanol, furfural tolerance assay.

Keywords: genetic recombinant, yeast, ethanol tolerance, trehalase, aldehyde reductase

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Authors: Jeisson A. Estrella, Laura C. Herrera, Cristian A. Arenas

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The Colombian electricity sector has been transforming through the insertion of new energy sources to generate electricity, one of them being solar energy, which is being promoted by companies interested in photovoltaic technology. The study of this technology is important for electricity generation in general and for the planning of the sector from the perspective of energy complementarity. Precisely in this last approach is where the project is located; we are interested in answering the concerns about the reliability of the electrical system when climatic phenomena such as El Niño occur or in defining whether it is viable to replace or expand thermoelectric plants. Reliability of the electrical system when climatic phenomena such as El Niño occur, or to define whether it is viable to replace or expand thermoelectric plants with renewable electricity generation systems. In this regard, some difficulties related to the basic information on renewable energy sources from measured data must first be solved, as these come from automatic weather stations. Basic information on renewable energy sources from measured data, since these come from automatic weather stations administered by the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM) and, in the range of study (2005-2019), have significant amounts of missing data. For this reason, the overall objective of the project is to complete the global solar irradiance datasets to obtain time series to develop energy complementarity analyses in a subsequent project. Global solar irradiance data sets to obtain time series that will allow the elaboration of energy complementarity analyses in the following project. The filling of the databases will be done through numerical and statistical methods, which are basic techniques for undergraduate students in technical areas who are starting out as researchers technical areas who are starting out as researchers.

Keywords: time series, global solar irradiance, imputed data, energy complementarity

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Authors: Regina Connolly, Murray Scott, William DeLone

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Social media are revolutionary technologies that are transforming the way we communicate, the way we collaborate and the way we influence. Companies are making major investments in platforms such as Facebook and Twitter because they realize that social media are an influential force on customer perceptions and behavior. However, to date there is little guidance on what constitutes an effective deployment of social media and there is no empirical evidence that social medial investments are yielding positive returns. This research develops and validates the components of an effective corporate social media platform in order to examine the impact of effective social media on customer intentions and behavior.

Keywords: service quality, social value, social media, IS success, Web 2.0, customer behaviour

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Authors: Kwasi Sarfo, Bernard Okoampah Otu

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The 1992 constitution of the Republic of Ghana recognises the authority and roles of traditional leaders and considers them as being entrusted with fiduciary responsibility over land in their respective territories. The new land act, Act 1036 of 2020, in buttressing the fiduciary role of traditional leaders in land matters, inserted the traditional leaders’ accountability clause. Many traditional leaders have expressed their misgivings about the insertion of this clause. Therefore, there appears to be a misunderstanding of the concept of fiduciary in land management in Ghana. The objective of this study is to examine the concept of fiduciary in respect of allodial rights holders in land management and administration and how this concept is perceived and applied by traditional leaders. The study seeks to provide insights into the discrepancy between fiduciary theory and its practical implementation in Ghana. The study is based on a qualitative empirical research approach and adopts in-depth interviews as a primary method of data collection. The study also adopts the theory of New Institutionalism of social anthropology in analysing and interpreting the findings. The data for this study was collected over a period of one year, from July 2022 to July 2023, as part of one of the author's PhD dissertation. The collected data were carefully analysed using the principles of thematic analysis, identifying key themes and patterns. This study does not seek to pursue the discussions from a legal standpoint but from a social anthropological perspective and argues that the concept of fiduciary in theory is far different from what pertains in practice and that traditional leaders’ assumptions and application of this concept contribute to the alienation of customary and communal land at the expense of their subjects. This study deepens our understanding of the continuous expropriation of communal landholders in many rural communities in Africa in the era of global land grabbing, which worsens their poverty levels. It also explains further the theory of new institutionalism of social anthropology by highlighting how the theory manifests in practice in the case of Ghana.

Keywords: fiduciary, customary land tenure, allodial rights, land alienation, communal land, Ghana

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Authors: Shabnam Dadparvar, Laijin Shen, Farzad Ravanbod

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Regarding the issues that are currently happening in the world, more than any other time the differences between West and Islam is under discussion. The cultural relations between Islam and the West took a drastically new turn when Europe arose as the dominant and unchallenged force of the modern era. The author, by using descriptive- analytical method, tries to analyse one of the most controversial questions facing analysts of relations between the Islamic world and the West: What are the roots of the conflict? This paper addresses the history of the intellectual tradition of the West and the attitude of Muslim world regarding the rise of western modernity. Also, the differences between two groups on philosophical foundations such as religion, power, science and humanism will be explained. The author believes that the real difference between the West and Islam is epistemological.

Keywords: civilization, culture, Islam, West

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Authors: Roberto Lorenzo

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Much has been said about the dynamics of the Latin American experience in the United States, however, there seems to be very little data regarding the perception of career identity. Although we do have some Latinos within the professional ranks, there is not nearly enough to claim that we have practiced enough cultural competence to create equity in the professional sphere in the United States. In this thesis, data will be provided regarding labor force statistics highlighting the industries that Latin Americans frequent. Also provided will be the citing of data that suggests further necessity of cultural competence within the professional realm regarding Latin Americans. In addition, methods that were spoken about over the course of our social work education will be discussed in order to connect to possible solutions to this issue.

Keywords: hiring, Latinos, professional equity, cultural competence

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Authors: Omar Omar, Yuan Jun, Hong Jinghua, Jin Chuanhong

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In this work molybdenum dioxide (MoO2) and sulphur powders are used to grow MoS2 mono layers at elevated temperatures T≥800 °C. Centimetre scale continues thin films with grain size up to 410 µm have been grown using chemical vapour deposition. To our best knowledge, these domains are the largest that have been grown so far. Advantage of our approach is not only because of the high quality films with large domain size one can produce, but also the procedure is potentially less hazardous than other methods tried. The thin films have been characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy.

Keywords: molybdenum disulphide (MoS2), monolayers, chemical vapour deposition (CVD), growth and characterization

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Authors: Sunghyun Kim, Hong-Gun Park

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In the performance-based design (PBD), by using the nonlinear dynamic analysis (NDA), the actual performance of the structure is evaluated. Unlike frame structures, in the wall structures, base shear force which is resulted from the NDA, is greatly amplified than that from the elastic analysis. This shear amplifying effect causes repeated designs which make designer difficult to apply the PBD. Therefore, in this paper, factors which affect shear amplification were studied. For the 20-story wall model, the NDA was performed. From the analysis results, the base shear amplification factor was proposed.

Keywords: performance based design, shear amplification factor, nonlinear dynamic analysis, RC shear wall

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Authors: S. Ritddech, P. Aroonjarattham, K. Aroonjarattham

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The pullout strength had an effect on the stability of plate screw fixation when inserted in the cervical spine. Nine different titanium alloy bone screws were used to test the pullout strength through finite element analysis. The result showed that the Moss Miami I can bear the highest pullout force at 1,075 N, which causes the maximum von Mises stress at 858.87 MPa, a value over the yield strength of titanium. The bone screw should have large outer diameter, core diameter and proximal root radius to increase the pullout strength.

Keywords: pullout strength, screw parameter, cervical spine, finite element analysis

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Authors: Shri Dubey, Jamal Ghorieshi

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Instability of the lumbar spine is caused by various factors that include degenerative disc, herniated disc, traumatic injuries, and other disorders. Pedicle screws are widely used as a main fixation device to construct rigid linkages of vertebrae to provide a fully functional and stable spine. Various technologies and methods have been used to restore the stabilization. However, loosening of pedicle screws is the main cause of concerns for neurosurgeons. This could happen due to poor bone quality with osteoporosis as well as types of pedicle screw used. Compatibilities and stabilities of pedicle screws with bone depend on design (thread design, length, and diameter) and material. Grip length and pullout strength affect the motion and stability of the spine when it goes through different phases such as extension, flexion, and rotation. Pullout strength of augmented pedicle screws is increased in both primary and salvage procedures by 119% (p = 0.001) and 162% (p = 0.01), respectively. Self-centering pedicle screws at different trajectories (0°, 10°, 20°, and 30°) show the same pullout strength as insertion in a straight-ahead trajectory. The outer cylindrical and inner conical shape of pedicle screws show the highest pullout strength in Grades 5 and 15 foams (synthetic bone). An outer cylindrical and inner conical shape with a V-shape thread exhibit the highest pullout strength in all foam grades. The maximum observed pullout strength is at axial pullout configuration at 0°. For Grade 15 (240 kg/m³) foam, there is a decline in pull out strength. The largest decrease in pullout strength is reported for Grade 10 (160 kg/m³) foam. The maximum pullout strength of 2176 N (0.32-g/cm³ Sawbones) on all densities. Type 1 Pedicle screw shows the best fixation due to smaller conical core diameter and smaller thread pitch (Screw 2 with 2 mm; Screws 1 and 3 with 3 mm).

Keywords: polymethylmethacrylate, PMMA, classical pedicle screws, CPS, expandable poly-ether-ether-ketone shell, EPEEKS, includes translaminar facet screw, TLFS, poly-ether-ether-ketone, PEEK, transfacetopedicular screw, TFPS

Procedia PDF Downloads 153

Authors: K. C. R.Perera, V. P. C Dassanayake, B. M. Hapuwatte, B. G. Smapath

Abstract:

This paper presents a methodology to harvest the kinetic energy of the raindrops using piezoelectric devices. In the study 1m×1m PVDF (Polyvinylidene fluoride) piezoelectric membrane, which is fixed by the four edges, is considered for the numerical simulation on deformation of the membrane due to the impact of the raindrops. Then according to the drop size of the rain, the simulation is performed classifying the rainfall types into three categories as light stratiform rain, moderate stratiform rain and heavy thundershower. The impact force of the raindrop is dependent on the terminal velocity of the raindrop, which is a function of raindrop diameter. The results were then analyzed to calculate the harvestable energy from the deformation of the piezoelectric membrane.

Keywords: raindrop, piezoelectricity, deformation, terminal velocity

Procedia PDF Downloads 321

Authors: Suleyman Ogul Ertugrul, Mustafa Turgut, Serkan Inandı, Mustafa Gorkem Coban, Mustafa Kıgılı, Ali Mert, Oguzhan Kesmez, Murat Ozancı, Caglar Uyulan

Abstract:

In high-performance automotive engineering, the realistic simulation of suspension systems is crucial for enhancing vehicle dynamics and handling. This study focuses on the double wishbone suspension system, prevalent in racing vehicles due to its superior control and stability characteristics. Utilizing MATLAB and Adams Car simulation software, we conduct a comprehensive analysis of displacement behaviors and damper sizing under various dynamic conditions. The initial phase involves using MATLAB to simulate the entire suspension system, allowing for the preliminary determination of damper size based on the system's response under simulated conditions. Following this, manual calculations of wheel loads are performed to assess the forces acting on the front and rear suspensions during scenarios such as braking, cornering, maximum vertical loads, and acceleration. Further dynamic force analysis is carried out using MATLAB Simulink, focusing on the interactions between suspension components during key movements such as bumps and rebounds. This simulation helps in formulating precise force equations and in calculating the stiffness of the suspension springs. To enhance the accuracy of our findings, we focus on a detailed kinematic and dynamic analysis. This includes the creation of kinematic loops, derivation of relevant equations, and computation of Jacobian matrices to accurately determine damper travel and compression metrics. The calculated spring stiffness is crucial in selecting appropriate springs to ensure optimal suspension performance. To validate and refine our results, we replicate the analyses using the Adams Car software, renowned for its detailed handling of vehicular dynamics. The goal is to achieve a robust, reliable suspension setup that maximizes performance under the extreme conditions encountered in racing scenarios. This study exemplifies the integration of theoretical mechanics with advanced simulation tools to achieve a high-performance suspension setup that can significantly improve race car performance, providing a methodology that can be adapted for different types of racing vehicles.

Keywords: FSAE, suspension system, Adams Car, kinematic

Procedia PDF Downloads 49

Authors: Shizrah Jamal, Robia Ghafoor, Farhan Raza

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Porcelain fused to metal crown is the most versatile variety of crown that is commonly placed worldwide. Various complications have been reported in the PFM crowns with use over the period of time. These include chipping of the porcelain, recurrent caries, loss of retention, open contacts, and tooth fracture. The objective of the present study was to determine the frequency of these complications in crowns cemented over a period of five years in a tertiary care hospital and also to report the survival of these crowns. A retrospective study was conducted in Dental clinics, Aga Khan University Hospital in which 150 PFM crowns cemented over a period of five years were evaluated. Patient demographics, oral hygiene habits, para-functional habits, crown insertion and follow-up dates were recorded in a specially designed proforma. All PFM crowns fulfilling the inclusion criteria were assessed both clinically and radiographically for the presence of any complication. SPSS version 22.0 was used for statistical analysis. Frequency distribution and proportion of complications were determined. Chi-square test was used to determine the association of complications of PFM crowns with multiple variables including tooth wear, opposing dentition and betel nut chewing. Kaplan- meier survival analysis was used to determine the survival of PFM crowns over the period of five years. Level of significance was kept at 0.05. A total of 107 patients, with a mean age of 43.51 + 12.4 years, having 150 PFM crowns were evaluated. The most common complication observed was open proximal contacts (8.7%) followed by porcelain chipping (6%), decementation (5.3%), and abutment fracture (1.3%). Chi square test showed that there was no statistically significant association of PFM crown complication with tooth wear, betel nut and opposing dentition (p-value <0.05). The overall success and survival rates of PFM crowns turned out to be 78.7 and 84.7% respectively. Within the limitations of the study, it can be concluded that PFM crowns are an effective treatment modality with high success and survival rates. Since it was a single centered study; the results should be generalized with caution.

Keywords: chipping, complication, crown, survival rate

Procedia PDF Downloads 207

Authors: Monique M. Keller, Roline Barnes, Corlia Brandt

Abstract:

Introduction Scientific evidence on the hand forces and the types of grasps measurement during daily tasks are lacking, leaving a gap in the field of hand rehabilitation and robotics. Measuring the grasp forces and types produced by the individual fingers during daily functional tasks is valuable to inform and grade rehabilitation practices for second to fifth metacarpal fractures with robust scientific evidence. Feix et al, 2016 identified the most extensive and complete grasp study that resulted in the GRASP taxonomy. Covid-19 virus changed data collection across the globe and safety precautions in research are essential to ensure the health of participants and researchers. Methodology A cross-sectional study investigated six healthy adults aged 20 to 59 years, pilot participants’ hand forces during 105 tasks. The tasks were categorized into five sections namely, personal care, transport and moving around, home environment and inside, gardening and outside, and office. The predominant grasp of each task was identified guided by the GRASP Taxonomy. Grasp forces were measured with 13mm force-sensing resistors glued onto a glove attached to each of the dominant and non-dominant hand’s individual fingers. Testing equipment included Flexiforce 13millimetres FSR .5" circle, calibrated prior to testing, 10k 1/4w resistors, Arduino pro mini 5.0v – compatible, Esp-01-kit, Arduino uno r3 – compatible board, USB ab cable - 1m, Ftdi ft232 mini USB to serial, Sil 40 inline connectors, ribbon cable combo male header pins, female to female, male to female, two gloves, glue to attach the FSR to glove, Arduino software programme downloaded on a laptop. Grip strength measurements with Jamar dynamometer prior to testing and after every 25 daily tasks were taken to will avoid fatigue and ensure reliability in testing. Covid-19 precautions included wearing face masks at all times, screening questionnaires, temperatures taken, wearing surgical gloves before putting on the testing gloves 1.5 metres long wires attaching the FSR to the Arduino to maintain social distance. Findings Predominant grasps observed during 105 tasks included, adducted thumb (17), lateral tripod (10), prismatic three fingers (12), small diameter (9), prismatic two fingers (9), medium wrap (7), fixed hook (5), sphere four fingers (4), palmar (4), parallel extension (4), index finger extension (3), distal (3), power sphere (2), tripod (2), quadpod (2), prismatic four fingers (2), lateral (2), large-diameter (2), ventral (2), precision sphere (1), palmar pinch (1), light tool (1), inferior pincher (1), and writing tripod (1). Range of forces applied per category, personal care (1-25N), transport and moving around (1-9 N), home environment and inside (1-41N), gardening and outside (1-26.5N), and office (1-20N). Conclusion Scientifically measurements of finger forces with careful consideration to types of grasps used in daily tasks should guide rehabilitation practices and robotic design to ensure a return to the full participation of the individual into the community.

Keywords: activities of daily living (ADL), Covid-19, force-sensing resistors, grasps, hand forces

Procedia PDF Downloads 189

Authors: Afshan Channa, Sameeha Aleem, Harim Mohsin

Abstract:

First rank symptoms (FRS) are considered to be pathognomic for Schizophrenia. However, FRS is not a distinctive feature of Schizophrenia. It has also been noticed in affective disorder, albeit not inclusive in diagnostic criteria. The presence of FRS in Mania leads to misdiagnosis of psychotic illness, further complicating the management and delay of appropriate treatment. FRS in Mania is associated with poor clinical and functional outcome. Its existence in the first episode of bipolar disorder may be a predictor of poor short-term outcome and decompensating course of illness. FRS in Mania is studied in west. However, the cultural divergence and detriments make it pertinent to study the frequency of FRS in affective disorder independently in Pakistan. Objective: The frequency of first rank symptoms in manic patients, who were under treatment at psychiatric services of tertiary care hospital. Method: The cross sectional study was done at psychiatric services of Aga Khan University Hospital, Karachi, Pakistan. One hundred and twenty manic patients were recruited from November 2014 to May 2015. The patients who were unable to comprehend Urdu or had comorbid psychiatric or organic disorder were excluded. FRS was assessed by administration of validated Urdu version of Present State Examination (PSE) tool. Result: The mean age of the patients was 37.62 + 12.51. The mean number of previous manic episode was 2.17 + 2.23. 11.2% males and 30.6% females had FRS. This association of first rank symptoms with gender in patients of mania was found to be significant with a p-value of 0.008. All-inclusive, 19.2% exhibited FRS in their course of illness. 43.5% had thought broadcasting, made feeling, impulses, action and somatic passivity. 39.1% had thought insertion, 30.4% had auditory perceptual distortion, and 17.4% had thought withdrawal. However, none displayed delusional perception. Conclusion: The study confirms the presence of FRS in mania in both male and female, irrespective of the duration of current manic illness or previous number of manic episodes. A substantial difference was established between both the genders. Being married had no protective effect on the presence of FRS.

Keywords: first rank symptoms, Mania, psychosis, present state examination

Procedia PDF Downloads 377

Authors: Erhan Turgut, Salih Ergün, Abdülkadir Öz

Abstract:

Terror is a modern war strategy which uses violence as a means of communication in order to achieve political objectives. In today’s security environment narrowing the propaganda field of terrorist organization is the primary goal for the security forces. In this sense, providing and maintaining public support is the most necessary ability for security units. Rather than enemy and threat-oriented approach, homeland security oriented approach is essential to ensure public support. In this study, terror assumed as a homeland security issue and assigning the law enforcement forces with military status is analyzed.

Keywords: terrorism, counter-terrorism, military status law-enforcement, terrorist groups

Procedia PDF Downloads 459