1,058 research outputs found
Parameter estimation of partial differential equations using artificial neural network
The work presented in this paper aims at developing a novel meshless parameter estimation framework for a system of partial differential equations (PDEs) using artificial neural network (ANN) approximations. The PDE models to be treated consist of linear and nonlinear PDEs, with Dirichlet and Neumann boundary conditions, considering both regular and irregular boundaries. This paper focuses on testing the applicability of neural networks for estimating the process model parameters while simultaneously computing the model predictions of the state variables in the system of PDEs representing the process. The capability of the proposed methodology is demonstrated with five numerical problems, showing that the ANN-based approach is very efficient by providing accurate solutions in reasonable computing times
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Legal skills: Ensuring āappy students
Law has been a little slow off the mark in the UK when it comes to the world of mobile applications (apps). In an environment where students spend more time using mobile applications than they do browsing the internet, the authors were keen to take their Learnmore website to the next stage by developing an app for law students. The Learnmore website (part of the Lawbore suite of resources from City University) has received much attention for its quirky visuals, multimedia learning tools and winning marriage of librarian and student generated content. With an ultimate aim of easing the transition between A-levels and degree and making the ābuilding blocksā of legal skills more interesting. Emily and Sanmeet secured substantial funding from JISC after a call for universities to create mobile apps from existing content, teaming up with a colleague in City University's Human Computer Interaction and Design department. The app was to be designed to help students learn essential legal skills in an innovative way, employing more interaction than was possible via the web. The emphasis on video content meant an early decision to fix on iPad rather than iPhone as the tool for mobile learning. The JISC funding paid for the services of a developer to help bring their ideas to life. This paper looks at the transformation from standard wiki to mobile application; focusing on the process of developing the concept for the app and the major milestones, as well as providing an insight into the expected challenges along the way. These included: working in a multidisciplinary team, communication of ideas, recognising the differences required in design for an app as opposed to a website and managing conflicting visions. The team motto was that creating an app cannot be simply a re-skinning process; but a re-working of content to to ensure a truly effective learning resource
Smoothening Transition of a Two-Dimensional Pressurized Polymer Ring
We revisit the problem of a two-dimensional polymer ring subject to an
inflating pressure differential. The ring is modeled as a freely jointed closed
chain of N monomers. Using a Flory argument, mean-field calculation and Monte
Carlo simulations, we show that at a critical pressure, , the
ring undergoes a second-order phase transition from a crumpled, random-walk
state, where its mean area scales as , to a smooth state with
. The transition belongs to the mean-field universality class. At
the critical point a new state of polymer statistics is found, in which
. For we use a transfer-matrix calculation to derive
exact expressions for the properties of the smooth state.Comment: 9 pages, 8 figure
Efektivitas Model Project Based Learning terhadap Hasil Belajar Siswa Kelas V SD Negeri Oebafok
Masalah dalam penelitian ini adalah untuk mengetahui apakah ada efektivitas yang signifikan terhadap hasil belajar siswa dengan menggunkan model project based learning tentang materi sistem peredaran darah pada manusia kelas V SD Negeri Oebafok Kabupaten Rote Ndao. Jenis penelitian adalah penelitian kuantitatif yaitu pre-experimental design secara khusus penelitian ini menggunakan rancangan penelitian one-group prettest-posttest design. Sampel yang digunakan peneliti sebanyak 20 siswa yang terdapat pada kelas V. Data yang dianalisis dalam penilitian ini adalah hasil belajar IPA yang di kumpulkan melalui tes pretest dan posttest, hasil penilitian yang dilakukan peniliti menunjukkan bahwa adanya perbandingan dari rata-rata posttest sebesar 78,20 > dari rata-rata nilai prestest yaitu 57,20. Selanjutnya hasil pengujian dianalisis menggunakan teknik analisis statistic paired samples test dibuktikan bahwa hasil perhitungan uji-t memiliki nilai t test sebesar 13,178 lebih besar (Ė) dari nilai t tabel 12, 621 pada taraf signifikansi 95% dan d.f 19 = 1.729. Jadi berdasarkan kritetia keputusan penerimaan/penolakan maka Ho ditolak dan HĪ± diterima. Peniliti menyimpulkan bahwa terdapat efektivitas yang signifikan terhadap hasil belajar siswa pada materi IPA tentang sistem peredaran darah pada manusia sebelum meggunakan dan sesudah menggunakan model project based learning
Optimal Model-Based Control of Non-Viral siRNA Delivery
Further quantitative understanding of the biological effects and mechanisms involved in cellular and intracellular delivery of nucleic acid materials is critical to produce clinical applications in the area of gene therapy. Several modeling approaches have been used in this field; however, a comprehensive approach that integrates all the key pharmacological issues into a holistic framework that is applicable for in vivo conditions is still lacking. This contribution presents a pharmacokinetic/pharmacodynamic model-based control study of non-viral siRNA delivery describing the dynamics of the delivery process and takes into account the main multi-objective optimization issues such as efficacy and toxicity, as well as the effect of uncertainty in cell doubling time. The methodology developed in this work is used to predict the optimal dosage injection rate and optimal intracellular exposure of siRNAs in order to improve pharmacological effects before cell division occurs. The present analysis successfully provides quantitative predictions of non-viral siRNA activity paving the path for further experimental work to probe more efficient delivery systems. This article is protected by copyright. All rights reserved
Optimisation of a liquid-liquid extraction based sustainable water desalination process
In this paper, a waste heat liquid-liquid extraction method is considered for the seawater
desalination. The mathematical model is a result of mass and energy balances, phase
behaviour and salt distribution in the two phases. Because of the high non-linearity of
the phase behaviour and the salt distribution these are being approximated by the use of
piecewise linear approximations methods and the solutions are presented. The results
indicate that the quality of solution is not affected by the use of the approximation
Cracking Characteristic of Asphalt Rubber Mixtures
The Arizona Department of Transportation (ADOT) has used Asphalt Rubber (AR) modified binders since the early 1970ās. The primary purpose for using AR is to reduce reflective cracking in Hot Mix Asphalt (HMA) rehabilitation overlays. The AR mixtures have also performed well in cold climate conditions. This research study had the primary objective of conducting a laboratory experimental program to obtain typical cracking properties for asphalt rubber mixtures used in Arizona and comparing the performance of these AR mixtures to other conventional asphalt mixtures. Gap and open graded mixtures were subjected to fatigue and indirect tensile cracking tests. All test specimens in this study were prepared using hot mix AR mixtures that were collected during construction. Fatigue testing of AR specimens was conducted at different test temperatures using the beam fatigue apparatus proposed by the Strategic Highway Research Program (SHRP). The indirect tensile strength and creep tests were carried out at three temperatures according to the procedures described in the draft indirect tensile test protocol developed for the new 2002 Design Guide. The results from the fatigue tests indicated that the AR mixtures would have longer fatigue life compared with the ADOT conventional dense graded mixtures. For the indirect tensile strength tests, the analysis for strains measured at failure showed that the AR mixtures have higher values than the conventional mixes. AR mixtures exhibiting higher strains at failure would have higher resistance to thermal cracking. The fracture energy results indicated that the AR mixtures are not as greatly affected by the decrease in temperature as compared to the conventional mixes. This relative insensitivity for changes in temperature makes the AR mixtures better resisting to thermal cracking in the field
Corneal decellularization: a method of recycling unsuitable donor tissue for clinical translation?
Background: There is a clinical need for biomimetic corneas that are as effective, preferably superior, to cadaveric donor tissue. Decellularized tissues are advantageous compared to synthetic or semi-synthetic engineered tissues in that the native matrix ultrastructure and intrinsic biological cues including growth factors, cytokines and glycosaminoglycans may be retained. However, there is currently no reliable, standardized human corneal decellularization protocol.
Methods: Corneal eye-bank tissue unsuitable for transplantation was utilized to systematically compare commonly used decellularization protocols. Hypertonic sodium chloride; an ionic reagent, sodium dodecyl sulphate; a non-ionic detergent, tert-octylphenol polyoxyethylene (Triton-X); enzymatic disaggregation using Dispase; mechanical agitation; and the use of nucleases were investigated. Decellularization efficacy, specifically for human corneal tissue, was extensively evaluated. Removal of detectable cellular material was evidenced by histological, immunofluorescence and biochemical assays. Preservation of macroscopic tissue transparency and light transmittance was evaluated. Retention of corneal architecture, collagen and glycosaminoglycans was assessed via histological, immunofluorescence and quantitative analysis. Biocompatibility of the resulting scaffolds was assessed using cell proliferation assays.
Results: None of the decellularization protocols investigated successfully removed 100% of cellular components. The techniques with the least residual cellular material were most structurally compromised. Biochemical analysis of glycosaminoglycans demonstrated the stripping effects of the decellularization procedures.
Conclusion: The ability to utilize, reprocess and regenerate tissues deemed āunsuitableā for transplantation allows us to salvage valuable tissue. Reprocessing the tissue has the potential to have a considerable impact on addressing the problems associated with cadaveric donor shortage. Patients would directly benefit by accessing greater numbers of corneal grafts and health authorities would fulfill their responsibility for the delivery of effective corneal reconstruction to alleviate corneal blindness. However, in order to progress, we may need to take a step back to establish a ādecellularizationā criterion; which should balance effective removal of immune reactive material with maintenance of tissue functionality
The use of innovative scaffolds in the development of corneal stroma-derived stem cell therapies for future corneal regeneration strategies [Abstract]
The use of innovative scaffolds in the development of corneal stroma-derived stem cell therapies for future corneal regeneration strategies [Abstract
Hands-On Projects and Exercises to Strengthen Understanding of Basic Computer Engineering Concepts
The Introduction to Computer Engineering course at the University of Missouri-Rolla provides a thorough understanding of basic digital logic analysis and design. The course covers: digital numbering systems, Boolean algebra, function minimization using Karnaugh maps (K-maps), memory elements, and sequential logic design. Students\u27 grades are determined by their performance on homework assignments, quizzes, and in-class examinations. A laboratory course (optional for all but EE and CpE majors) supplements the lecture by providing experiments that include analysis and design using Mentor Graphics and FPGAs. While the laboratory is a very useful supplement to the lecture, almost half the students taking the lecture are not required to take the laboratory and there is not sufficient time in the laboratory schedule to introduce significant design elements. In Fall 2004, hands-on group projects, for all students, were introduced to the lecture course. The goal was for students to develop a more practical understanding and appreciation of hardware design and to improve motivation. Two projects were introduced that involve design of simple digital systems (based on practical applications), design optimization, and physical realization of the system using logic gates and/or memory elements. Two surveys, conducted during the semester, show the benefit of hands-on projects in gaining experience on basic digital hardware design
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