Search results for: Stephen. F. Benjamin

Authors: Jacob Wood, David Wilson, Stephen Hughes

Abstract:

The Ausmelt Top Submerged Lance (TSL) Process has been widely applied for the processing of both primary and secondary copper, nickel, lead, tin, and zinc-bearing feed materials. Continual development and evolution of the technology over more than 30 years has resulted in a more intense smelting process with higher energy efficiency, improved metal recoveries, lower operating costs, and reduced fossil fuel consumption. This paper covers a number of recent advances to the technology, highlighting their positive impacts on smelter operating costs, environmental performance, and contribution towards increased circularity in metals production.

Keywords: ausmelt TSL, smelting, circular economy, energy efficiency

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Authors: Lei Ren, Michael Hartnett, Stephen Nash

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The abundant measured surface current from HF radar system in coastal area is assimilated into model to improve the modeling forecasting ability. A simple sequential data assimilation scheme, Direct Insertion (DI), is applied to update model forecast states. The influence of Direct Insertion data assimilation over time is analyzed at one reference point. Vector maps of surface current from models are compared with HF radar measurements. Root-Mean-Squared-Error (RMSE) between modeling results and HF radar measurements is calculated during the last four days with no data assimilation.

Keywords: data assimilation, CODAR, HF radar, surface current, direct insertion

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Authors: Vanessa Romanovicz, Beatriz A. Berns, Stephen D. Carpenter, Deyse Carpenter

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This article deals with the carbon nanotubes (CNT) synthesized from a novel precursor, sugar cane and Anodic Aluminum Oxide (AAO). The objective was to produce CNTs to be used as catalyst supports for Proton Exchange Membranes. The influence of temperature, inert gas flow rate and concentration of the precursor is presented. The CNTs prepared were characterized using TEM, XRD, Raman Spectroscopy, and the surface area determined by BET. The results show that it is possible to form CNT from sugar cane by pyrolysis and the CNTs are the type multi-walled carbon nanotubes. The MWCNTs are short and closed at the two ends with very small surface area of SBET = 3.691m,/g.

Keywords: carbon nanotubes, sugar cane, fuel cell, catalyst support

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Authors: Okike Benjamin, Garba E J. D.

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Encryption is used to conceal information from prying eyes. Presently, information and data encryption are common due to the volume of data and information in transit across the globe on daily basis. Image encryption is yet to receive the attention of the researchers as deserved. In other words, video and multimedia documents are exposed to unauthorized accessors. The authors propose image encryption using matrix transpose. An algorithm that would allow image encryption is developed. In this proposed image encryption technique, the image to be encrypted is split into parts based on the image size. Each part is encrypted separately using matrix transpose. The actual encryption is on the picture elements (pixel) that make up the image. After encrypting each part of the image, the positions of the encrypted images are swapped before transmission of the image can take place. Swapping the positions of the images is carried out to make the encrypted image more robust for any cryptanalyst to decrypt.

Keywords: image encryption, matrices, pixel, matrix transpose

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Authors: David Pettitt, Benjamin Davies, Georg Holländer, David Brindley

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Cellular based therapies, whose origins can be traced from the intertwined concepts of tissue engineering and regenerative medicine, have the potential to transform the current medical landscape and offer an approach to managing what were once considered untreatable diseases. However, despite a large increase in basic science activity in the cell therapy arena alongside a growing portfolio of cell therapy trials, the number of industry products available for widespread clinical use correlates poorly with such a magnitude of activity, with the number of cell-based therapeutics in mainstream use remaining comparatively low. This research serves to quantitatively assess the barriers to the clinical adoption of cell-based therapeutics through identification of unique barriers, specific challenges and opportunities facing the development and adoption of such therapies.

Keywords: cell therapy, clinical adoption, commercialization, translation

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Authors: Mohammad Samarah, Benjamin Stark, Jennifer Kindle, Langley Payton

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Innovation is a key driver for companies, society, and economic growth. However, assessing and measuring innovation for individuals as well as organizations remains difficult. Our i5-Score presented in this study will help to overcome this difficulty and facilitate measuring the innovation potential. The score is based on a framework we call the 5Gs of innovation which defines specific innovation attributes. Those are 1) the drive for long-term goals 2) the audacity to generate new ideas, 3) the openness to share ideas with others, 4) the ability to grow, and 5) the ability to maintain high levels of optimism. To validate the i5-Score, we conducted a study at Florida Polytechnic University. The results show that the i5-Score is a good measure reflecting the innovative mindset of an individual or a group. Thus, the score can be utilized for evaluating, refining and enhancing innovation capabilities.

Keywords: Change Management, Innovation Attributes, Organizational Development, STEM and Venture Creation

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Authors: Osholana Tobi Stephen, Rotimi Emmanuel Sadiku, Bilainu Oboirien.o

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Fluidized bed combustion (FBC) is a clean coal technology used in the combustion of low-grade coals for power generation. The production of large solid wastes such as bottom ashes from this process is a problem. The bottom ash contains some toxic elements which can leach out soils and contaminate surface and ground water; for this reason, they can neither be disposed in landfills nor lagoons anymore. The production of geopolymers from bottom ash for structural and concrete applications is an option for their disposal. In this study, the waste bottom ash obtained from the combustion of three low grade South African coals in a bubbling fluidized bed reactor was used to produce geopolymers. The geopolymers were cured in a household microwave. The results showed that the microwave curing enhanced the reactivity and strength of the geopolymers.

Keywords: bottom ash, coal, fluidized bed combustion (FBC) geopolymer, compressive strength

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Authors: Chris Landorf, Stephen Ward

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This paper addresses a virtual environment approach to work integrated learning for students in construction-related disciplines. The virtual approach provides a safe and pedagogically rigorous environment where students can apply theoretical knowledge in a simulated real-world context. The paper describes the development of a 4-dimensional digital construction environment and associated learning activities funded by the Australian Office for Learning and Teaching. The environment was trialled with over 1,300 students and evaluated through questionnaires, observational studies and coursework analysis. Results demonstrate a positive impact on students’ technical learning and collaboration skills, but there is need for further research in relation to critical thinking skills and work-readiness.

Keywords: architectural education, construction industry, digital learning environments, immersive learning

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Authors: Oluropo Stephen Ilesanmi, Oluwole Ayodele Alejo

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Architectural education, beyond training the students to become architects, impacts in them the appreciation of the responsibilities relating to public health, safety, and welfare. Architecture is no longer a personal philosophical or aesthetic pursuit by individuals, rather, it has to consider everyday needs of the people and use technology to give a liveable environment. In the present age, architectural education must have to grapple with the recent integration of technology, in particular, facilities offered by information and communication technology. Electronic technologies have moved architecture from the drawing board to cyberspace. The world is now a global village in which new information and methods are easily and quickly available to people at different poles of the globe. It is the position of this paper that in order to remain relevant in the ever-competing forces within the building industry, architectural education must show the impetus to continue to draw from technological advancements associated with the use of computers.

Keywords: architecture, education, communication, information, technology

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Authors: Benjamin Anderson-Sackaney, Amr Abdel-Dayem

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This paper presents a comprehensive survey of recent source camera identification (SCI) systems. Then, the performance of various sensor pattern noise (SPN) estimators was experimentally assessed, under common photo response non-uniformity (PRNU) frameworks. The experiments used 1350 natural and 900 flat-field images, captured by 18 individual cameras. 12 different experiments, grouped into three sets, were conducted. The results were analyzed using the receiver operator characteristic (ROC) curves. The experimental results demonstrated that combining the basic SPN estimator with a wavelet-based filtering scheme provides promising results. However, the phase SPN estimator fits better with both patch-based (BM3D) and anisotropic diffusion (AD) filtering schemes.

Keywords: sensor pattern noise, source camera identification, photo response non-uniformity, anisotropic diffusion, peak to correlation energy ratio

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Authors: Benjamin Legros, Jan Fransoo, Oualid Jouini

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This study aims to evaluate street-turn strategies for empty container repositioning in the hinterland. Containers arrive over time at the (importer) consignee, while the demand for containers arises from the (exporter) shipper. A match can be operated between an empty container from the consignee and the load from the shipper. Therefore, we model the system as a double-ended queue with non-zero matching time and a limited number of resources in order to optimize the reposition- ing decisions. We determine the performance measures when the consignee operates using a fixed withholding threshold policy. We show that the matching time mainly plays a role in the matching proportion, while under a certain duration, it only marginally impacts the consignee’s inventory policy and cost per container. Also, the withholding level is mainly determined by the shipper’s production rate.

Keywords: container, double-ended queue, inventory, Markov decision process, non-zero matching time, street-turn

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Authors: Yuting Wu, Faraz Choudhury, Daniel Benjamin, James Whalin, Joshua Blatz, Leon Shohet, Michael Sussman, Mark Richards

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Plasma-Induced Modification of Biomolecules (PLIMB) has been developed as a technology, which, together with mass spectrometry, measures three-dimensional structural characteristics of proteins. This technique uses hydroxyl radicals generated by atmospheric-pressure plasma discharge to react with the solvent-accessible side chains of protein in an aqueous solution. In this work, we investigate the three-dimensional structure of hemoglobin and myoglobin using PLIMB. Additional modifications to these proteins, such as oxidation, fragmentations, and conformational changes caused by PLIMB are also explored. These results show that PLIMB, coupled with mass spectrometry, is an effective way to determine solvent access to hemoproteins. Furthermore, we show that many factors, including pH and the electrical parameters used to generate the plasma, have a significant influence on solvent accessibility.

Keywords: plasma, hemoglobin, myoglobin, solvent access

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Authors: Stephen Gerome

Abstract:

This study examines the translation and use of metaphors in the realm of public safety discourse and intends to shed light on a continuing problem in cross-cultural communication. Metaphors can cause problems not only within languages but also in interlingual communication. The use and misuse of metaphors may hinder the ability to adequately communicate prevention efforts and, in some cases, facilitate and allow financial crime to go undetected. The use of lexicalized metaphors in communications by political entities, journalists, and legal agents in communications regarding law, policy making, compliance monitoring and enforcement as well as in adjudication can have negative consequences if misconstrued. This study provides examples of metaphor usage in published documents in a corpus linguistic study that compares the use of lexicalized metaphors in this discourse to shed light on possible unexpected consequences as well as counterproductive ones.

Keywords: translation, legal, corpus linguistics, financial

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Authors: Adavbiele Airewe Stephen

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Sustainable energy use is exploiting energy resources within acceptable levels of global resource depletion without destroying the ecological balance of an area. In the context of sustainability, the rush to quell the energy crisis of the fossil fuels of the 1970's by embarking on nuclear energy technology has now been seen as a disaster. In the circumstance, action (policy) suggested in this study to avoid future occurrence is exergy maximization/entropy generation minimization and the use is renewable energy technologies that are hybrid based. Thirty-two (32) selected hybrid renewable energy technologies were assessed with respect to their energetic efficiencies and entropy generation. The results indicated that determining which of the hybrid technologies is the most efficient process and sustainable is a matter of defining efficiency and knowing which of them possesses the minimum entropy generation.

Keywords: entropy, exergy, hybrid renewable energy technologies, sustainability

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Authors: Stephen E. Cross, Donald P. McConnell

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In the past decade, market pressures and decreasing U.S. federal budgets for science and technology have led to a fundamental change in expectations for corporate investments in innovation. The trend to significant, sustained corporate research collaboration with major academic centres has called for rethinking the balance between academic and corporate roles in these relationships. The Georgia Institute of Technology has developed a system-focused strategy for transformational research focused on grand challenges in areas of importance both to faculty and to industry collaborators. A model of an innovation ecosystem is used to guide both research and university-industry collaboration. The paper describes the strategy, the model, and the results to date including the benefits both to university research and industry collaboration. Key lessons learned are presented based on this experience.

Keywords: ecosystem, industry collaboration, innovation, research strategy

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Authors: Stephen A. Akinlabi, Esther T. Akinlabi

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The drip irrigation system is one of the important areas that affect the livelihood of farmers directly. The use of drip irrigation system has been the most efficient system compared to the other types of irrigations systems because the drip irrigation helps to save water and increase the productivity of crops. But like any other system, it can be considered inefficient when the filters and the emitters get clogged while in operation. The efficiency of the entire system is reduced when the emitters are clogged and blocked. This consequently impact and affect the farm operations which may result in scarcity of farm products and increase the demand. This design work focuses on how to overcome some of the challenges affecting drip irrigation system through the design of an efficient filtration and flushing system.

Keywords: drip irrigation system, filters, soil texture, mechanical engineering design, analysis

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Authors: David Ming Liu, Benjamin Hirsch, Bashir Aden

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Syndromic surveillance is to detect or predict disease outbreaks through the analysis of medical sources of data. Using social media data like tweets to do syndromic surveillance becomes more and more popular with the aid of open platform to collect data and the advantage of microblogging text and mobile geographic location features. In this paper, a Syndromic Surveillance Framework is presented with machine learning kernel using tweets data analytics. Influenza and the three cities Abu Dhabi, Al Ain and Dubai of United Arabic Emirates are used as the test disease and trial areas. Hospital cases data provided by the Health Authority of Abu Dhabi (HAAD) are used for the correlation purpose. In our model, Latent Dirichlet allocation (LDA) engine is adapted to do supervised learning classification and N-Fold cross validation confusion matrix are given as the simulation results with overall system recall 85.595% performance achieved.

Keywords: Syndromic surveillance, Tweets, Machine Learning, data mining, Latent Dirichlet allocation (LDA), Influenza

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Authors: Ganiyu I. Lawal, Olatunde I. Sekunowo, Stephen I. Durowaye

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Composites depending on the nature of their constituents and mode of production are regarded as one of the advanced materials that drive today’s technology. This paper attempts a short review of the subject matter with a general aim of pushing to the next level the frontier of knowledge as it impacts the technology of nano-particles manufacturing. The objectives entail an effort to; aggregate recent research efforts in this field, analyse research findings and observations, streamline research efforts and support industry in taking decision on areas of fund deployment. It is envisaged that this work will serve as a quick hand-on compendium material for researchers in this field and a guide to relevant government departments wishing to fund a research whose outcomes have the potential of improving the nation’s GDP.

Keywords: advanced materials, composites, mechanical properties, nano-particles

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Authors: Shakhawan K. Mawlood, Catriona Pickard, Benjamin Pickard

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In summer 2015 the remains of 800 children are among 1,967 bodies were exhumed by archaeologists at St Peter's Burial Ground in Blackburn, Lancashire. One hundred samples from these 19th century ancient bones were selected for DNA analysis. These comprised samples biased for those which prior osteological evidence indicated a potential for microbial infection by Mycobacterium tuberculosis (causing tuberculosis, TB) or Treponema pallidum (causing Syphilis) species, as well a random selection of other bones for which visual inspection suggested good preservation (and, therefore, likely DNA retrieval).They were subject to polymerase chain reaction (PCR) assays aimed at detecting traces of DNA from infecting mycobacteria, with the purpose both of confirming the palaeopathological diagnosis of tuberculosis and determining in individual cases whether disease and death was due to M. tuberculosis or other reasons. Our secondary goal was to determine sex determination and age prediction. The results demonstrated that extraction of vast majority ancient bones DNA samples succeeded.

Keywords: ancient bone, DNA, tuberculosis, age prediction

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Authors: Mykhailo Moskalets, Pablo Burset, Benjamin Roussel, Christian Flindt

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The single-particle injection from the Andreev level and how such injection is simulated using a voltage pulse are discussed. Recently, high-speed quantum-coherent electron sources injecting one- to few-particle excitations into the Fermi sea have been experimentally realized. The main obstacle to using these excitations as flying qubits for quantum-information processing purposes is decoherence due to the long-range Coulomb interaction. An obvious way to get around this difficulty is to employ electrically neutral excitations. Here it is discussed how such excitations can be generated on-demand using the same injection principles as in existing electron sources. Namely, with the help of a voltage pulse of a certain shape applied to the Fermi sea or using a driven quantum dot with superconducting correlations. The advantage of the latter approach is the possibility of varying the electron-hole content in the excitation and the possibility of creating a charge-neutral but spin-dipole excitation.

Keywords: Andreev level, on-demand, single-electron, spin-dipole

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Authors: Stephen Kirkup

Abstract:

This paper discusses the implementation of the boundary element method (BEM) on an Excel spreadsheet and how it can be used in teaching vector calculus and simulation. There are two separate spreadheets, within which Laplace equation is solved by the BEM in two dimensions (LIBEM2) and axisymmetric three dimensions (LBEMA). The main algorithms are implemented in the associated programming language within Excel, Visual Basic for Applications (VBA). The BEM only requires a boundary mesh and hence it is a relatively accessible method. The BEM in the open spreadsheet environment is demonstrated as being useful as an aid to teaching and learning. The application of the BEM implemented on a spreadsheet for educational purposes in introductory vector calculus and simulation is explored. The development of assignment work is discussed, and sample results from student work are given. The spreadsheets were found to be useful tools in developing the students’ understanding of vector calculus and in simulating heat conduction.

Keywords: boundary element method, Laplace’s equation, vector calculus, simulation, education

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Authors: Akinyemi Benjamin

Abstract:

This study investigates the prevailing HRDC Nigerian commercial banks as perceived by employees in general. The perceptional differences on the state of HRDC by gender category are also examined. Using Abraham and Rao’s HRDC 38-item questionnaire, data from 310 respondents, with 303 valid responses, were entered into excel sheet and analysed to determine frequencies, mean scores, standard deviation and percentages for four variables: HRDC, general climate, HRD mechanism, and OCTAPAC culture. Results of analysis indicate that generally, employees perceive the overall HRDC and its three dimensions of general climate, HRD mechanism and OCTAPAC culture to be at an average or moderate level. The perceptions of both male and female subjects also indicate an average HRDC level although participants report slightly higher scores than their male subjects but these scores are still at an average level on all the dimensions of HRDC measured. The implications of this result for organizations in general and the banking industry in particular are discussed.

Keywords: HRDC, HRD mechanism, general climate, OCTAPAC culture, gender

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Authors: Mncedisi Trinity Dewa, Andre Francois Van Der Merwe, Stephen Matope

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Tool, Die and Mould-making (TDM) firms have been known to play a pivotal role in the growth and development of the manufacturing sectors in most economies. Their output contributes significantly to the quality, cost and delivery speed of final manufactured parts. Unfortunately, the South African Tool, Die and Mould-making manufacturers have not been competing on the local or global market in a significant way. This reality has hampered the productivity and growth of the sector thus attracting intervention. The paper explores the shortcomings South African toolmakers have to overcome to restore their competitive position globally. Results from a global benchmarking survey on the tooling sector are used to establish a roadmap of what South African toolmakers can do to become a productive, World Class force on the global market.

Keywords: competitive performance objectives, toolmakers, world-class manufacturing, lead times

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Authors: Lincy Stephen, N. Yogesh, G. Vasantharajan, V. Subramanian

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This paper presents the design and simulation of a five band metamaterial absorber at microwave frequencies. The absorber unit cell consists of squares and strips arranged as the top layer and a metallic ground plane as the bottom layer on a dielectric substrate. Simulation results show five near perfect absorption bands at 3.15 GHz, 7.15 GHz, 11.12 GHz, 13.87 GHz, and 16.85 GHz with absorption magnitudes 99.68%, 99.05%, 96.98%, 98.36% and 99.44% respectively. Further, the proposed absorber exhibits polarization insensitivity and wide angle receptivity. The surface current analysis is presented to explain the mechanism of absorption in the structure. With these preferable features, the proposed absorber can be excellent choice for potential applications such as electromagnetic interference (EMI) shielding, radar cross section reduction.

Keywords: electromagnetic absorber, metamaterial, multi- band, polarization insensitive, wide angle receptive

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Authors: Benjamin Panreck, Manfred Hild

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Strain sensors based on a change in resistance are well established for the measurement of forces, stresses, or material fatigue. Within the scope of this paper, fully additive manufactured strain sensors were produced using an ink of silver nanoparticles. Their behavior was evaluated by periodic tensile tests. Printed strain sensors exhibit two advantages: Their measuring grid is adaptable to the use case and they do not need a carrier-foil, as the measuring structure can be printed directly onto a thin sprayed varnish layer on the aluminum specimen. In order to compare quality characteristics, the sensors have been manufactured using two different technologies, namely aerosoljet-printing and micropipette-dispensing. Both processes produce structures which exhibit continuous features (in contrast to what can be achieved with droplets during inkjet printing). Briefly summarized the results show that aerosoljet-printing is the preferable technology for specimen with non-planar surfaces whereas both technologies are suitable for flat specimen.

Keywords: aerosoljet-printing, micropipette-dispensing, printed electronics, printed sensors, strain gauge

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Authors: Wandera Stephen Ojumbo

Abstract:

People living with hearing impairment in Uganda are one of the most excluded minority groups in the country. The Uganda National Association of the Deaf estimates that deaf people make up 3.4% of Uganda’s 43 million people. Deaf Children and youth often appear withdrawn because they face social stigma. In 2009, photojournalist Stephen Wandera Ojumbo conducted an exhibition in Kampala titled “Silent Voices with colourful Hearts” showcasing the life of deaf children at Uganda School for the Deaf, Ntinda, in order to create awareness of their plight, raising funds for the construction of a vocational centre for the deaf that didn’t continue their education due to: lack of funds, non-inclusive educational institutions, and for those who cannot read and write. These children, whose lives were exhibited in 2009, are currently youths. In Uganda, there are just five primary schools for the deaf (three of these are located in Kampala, the capital city), and barely five secondary schools for the deaf. At the moment, some deaf children only receive special needs training equivalent to primary seven levels and the majority don’t make it to secondary school education level due to the fact that English is a second language to them. There is a communication gap between speaking parents and deaf children, which leads to the breakage of family bonds. The deaf youth run away from their homes to form a community where they can communicate freely. Likewise, employment opportunities for the deaf are equally very limited. It’s for this reason that a follow-up photo exhibition was conducted to expose more about what the youthful deaf people and their guardians go through in Uganda to get jobs, live and fit in the community, how they communicate and get understood, bonding with families instead of running away to bond with fellow deaf persons. The photo exhibition under the theme “Loud Silence” was significant in showcasing the ability of deaf youths in Uganda and eliciting solutions to make a more inclusive society for the deaf. It is hoped that partners in development will join in for intervention. The methodology used included individual interviews with the deaf youth and their parents and caretakers; photography at household and community levels; document review at organizations working with the deaf; observations; and key informant interviews with relevant personnel working with the deaf. Some of the major findings include: i) Effective sign language communication is key in deaf education, family bonding, and developing a sense of belonging; ii) Love and intimacy can keep the deaf bound together; iii) Education is important; everybody should struggle even if alone; iv) Games and sports are a unifying factor and most loved among the deaf; and v) better communication skills build confidence in deaf youth. In conclusion, concerted efforts are still needed to make Uganda schools more inclusive for deaf persons. This will enable a secure future for deaf youths.

Keywords: deaf, education, excluded, photo exhibition

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Authors: Benjamin Leiby, Darryl Ahner

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This study demonstrates an alternative stochastic imputation approach for large datasets when preferred commercial packages struggle to iterate due to numerical problems. A large country conflict dataset motivates the search to impute missing values well over a common threshold of 20% missingness. The methodology capitalizes on correlation while using model residuals to provide the uncertainty in estimating unknown values. Examination of the methodology provides insight toward choosing linear or nonlinear modeling terms. Static tolerances common in most packages are replaced with tailorable tolerances that exploit residuals to fit each data element. The methodology evaluation includes observing computation time, model fit, and the comparison of known values to replaced values created through imputation. Overall, the country conflict dataset illustrates promise with modeling first-order interactions while presenting a need for further refinement that mimics predictive mean matching.

Keywords: correlation, country conflict, imputation, stochastic regression

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Authors: Lamia L. G. Al-Mahamad, Benjamin R. Horrocks, Andrew Houlton

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Hydrogels based on metal coordination polymers of nucleosides and a range of metal ions (Au, Ag, Cu) have been prepared and characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy, and powder X-ray diffraction. AFM images of the xerogels revealed the formation of extremely long polymer molecules (> 10 micrometers, the maximum scan range). This result is also consistent with TEM images which show a fibrous morphology. Oxidative doping of the Au-nucleoside fibres produces an electrically conductive nanowire. No sharp Bragg peaks were found at the at the X-ray diffraction pattern for metal ions hydrogels indicating that the samples were amorphous, but instead the data showed broad peaks in the range 20 < Q < 40 and correspond to distances d=2μ/Q. The data was analysed using a simplified Rietveld method by fitting a regression model to obtain the distance between atoms.

Keywords: hydrogel, metal ions, nanowire, nucleoside

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Authors: Khamael M. Abualnaja, Lidija Šiller, Benjamin R. Horrocks

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Metal-enhanced luminescence of silicon nano crystals (SiNCs) was determined using two different particle sizes of silver nano particles (AgNPs). SiNCs have been characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photo electron spectroscopy (XPS). It is found that the SiNCs are crystalline with an average diameter of 65 nm and FCC lattice. AgNPs were synthesized using photochemical reduction of AgNO3 with sodium dodecyl sulphate (SDS). The enhanced luminescence of SiNCs by AgNPs was evaluated by confocal Raman microspectroscopy. Enhancement up to ×9 and ×3 times were observed for SiNCs that mixed with AgNPs which have an average particle size of 100 nm and 30 nm, respectively. Silver NPs-enhanced luminescence of SiNCs occurs as a result of the coupling between the excitation laser light and the plasmon bands of AgNPs; thus this intense field at AgNPs surface couples strongly to SiNCs.

Keywords: silver nanoparticles, surface enhanced raman spectroscopy (SERS), silicon nanocrystals, luminescence

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Authors: Mohammadjavad Yaghoubi, Arul Arulrajah, Mahdi M. Disfani, Suksun Horpibulsuk, Myint W. Bo, Stephen P. Darmawan

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Utilising waste materials, such as fly ash (FA) and slag (S) stockpiled in landfills, has drawn the attention of researchers and engineers in the recent years. There is a great potential for usage of these wastes in ground improvement projects, especially where deep deposits of soft compressible soils exist. This paper investigates the changes in the strength development of a high water content soft soil stabilised with alkaline activated FA and S, termed as geopolymer binder, to use in deep soil mixing technology. The strength improvement and the changes in the microstructure of the mixtures have been studied. The results show that using FA and S-based geopolymers can increases the strength significantly. Furthermore, utilising FA and S in ground improvement projects, where large amounts of binders are required, can be a solution to the disposal of these wastes.

Keywords: alkaline activation, fly ash, geopolymer, slag, strength development

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