82 research outputs found

    The invention of photography

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    Photography was invented in the first half of the XIX century. The word "photography" comes from the Greek words " Fotos " ( light) and "The Count " ( write ) and means “light painting ." When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3484

    A methodology for rapid vehicle scaling and configuration space exploration

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    Drastic changes in aircraft operational requirements and the emergence of new enabling technologies often occur symbiotically with advances in technology inducing new requirements and vice versa. These changes sometimes lead to the design of vehicle concepts for which no prior art exists. They lead to revolutionary concepts. In such cases the basic form of the vehicle geometry can no longer be determined through an ex ante survey of prior art as depicted by aircraft concepts in the historical domain. Ideally, baseline geometries for revolutionary concepts would be the result of exhaustive configuration space exploration and optimization. Numerous component layouts and their implications for the minimum external dimensions of the resultant vehicle would be evaluated. The dimensions of the minimum enclosing envelope for the best component layout(s) (as per the design need) would then be used as a basis for the selection of a baseline geometry. Unfortunately layout design spaces are inherently large and the key contributing analysis i.e. collision detection, can be very expensive as well. Even when an appropriate baseline geometry has been identified, another hurdle i.e. vehicle scaling has to be overcome. Through the design of a notional Cessna C-172R powered by a liquid hydrogen Proton Exchange Membrane (PEM) fuel cell, it has been demonstrated that the various forms of vehicle scaling i.e. photographic and historical-data-based scaling can result in highly sub-optimal results even for very small O(10-3) scale factors. There is therefore a need for higher fidelity vehicle scaling laws especially since emergent technologies tend to be volumetrically and/or gravimetrically constrained when compared to incumbents. The Configuration-space Exploration and Scaling Methodology (CESM) is postulated herein as a solution to the above-mentioned challenges. This bottom-up methodology entails the representation of component or sub-system geometries as matrices of points in 3D space. These typically large matrices are reduced using minimal convex sets or convex hulls. This reduction leads to significant gains in collision detection speed at minimal approximation expense. (The Gilbert-Johnson-Keerthi algorithm is used for collision detection purposes in this methodology.) Once the components are laid out, their collective convex hull (from here on out referred to as the super-hull) is used to approximate the inner mold line of the minimum enclosing envelope of the vehicle concept. A sectional slicing algorithm is used to extract the sectional dimensions of this envelope. An offset is added to these dimensions in order to come up with the sectional fuselage dimensions. Once the lift and control surfaces are added, vehicle level objective functions can be evaluated and compared to other designs. For each design, changes in the super-hull dimensions in response to perturbations in requirements can be tracked and regressed to create custom geometric scaling laws. The regressions are based on dimensionally consistent parameter groups in order to come up with dimensionally consistent and thus physically meaningful laws. CESM enables the designer to maintain design freedom by portably carrying multiple designs deeper into the design process. Also since CESM is a bottom-up approach, all proposed baseline concepts are implicitly volumetrically feasible. Furthermore the scaling laws developed from custom data for each concept are subject to less design noise than say, regression based approaches. Through these laws, key physics-based characteristics of vehicle subsystems such as energy density can be mapped onto key system level metrics such as fuselage volume or take-off gross weight. These laws can then substitute some historical-data based analyses thereby improving the fidelity of the analyses and reducing design time.Ph.D.Committee Chair: Dr. Dimitri Mavris; Committee Member: Dean Ward; Committee Member: Dr. Daniel Schrage; Committee Member: Dr. Danielle Soban; Committee Member: Dr. Sriram Rallabhandi; Committee Member: Mathias Emenet

    Evaluation of Arsenic and Selenium Quantitation in Marcellus Shales and Flowback Saline Waters using Thiol Cotton Fibre-Graphite Furnace Atomic Absorption Spectroscopy and Diffusive Gradient in Thin Film Techniques

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    Trace levels of arsenic and selenium can be toxic to living organisms yet their quantitation in high ionic strength or high salinity aqueous media is difficult due to the matrix interferences which can either suppress or enhance the analyte signal. The objective of this proposed study has been to apply and/or modify inexpensive, simple, and interference-free analytical methods for the sub-ppb to ppb quantification of both inorganic and bioavailable arsenic and selenium fractions in highly saline/salty waters such as flowback wastewater produced from natural gas well drilling sites in the Marcellus shale and/or simulated or artificial high-salinity prepared from deionized water and spikes of different ions, selenium and arsenic concentrations.;A modified thiol cotton fiber (TCF) method employing lower flow rates and centrifugation has been developed and used to remove the analyte from complex aqueous media and minimize the matrix interferences. This method has been tested using a USGS (SGR-1b) certified reference shale. It has been used to analyze Marcellus shale samples following microwave digestion as well as spiked samples of high salinity water (HSW) and flowback wastewater (WRF6) obtained from an actual gas well drilling operation. Quantitation of arsenic and selenium was carried out by graphite furnace atomic spectroscopy (GFAAS). Extraction of arsenic and selenium from Marcellus shale exposed to HSW and WRF6 for varying lengths of time is also reported.;In addition, the role of hydrofluoric acid in microwave-assisted digestion and in the elimination of spectral interferences from the aluminum matrix at 189 nm for arsenic quantitation by GFAAS with deuterium lamp back-ground correction has been investigated. When sufficient amounts of hydrofluoric acid are added to the sample for microwave-assisted digestion, the excess or residual hydrofluoric acid serves an additional role of matrix modification to inhibit the formation of aluminum oxide that has been reported to cause the spectral interference. The presence of sufficient fluoride in the sample enables formation of aluminum fluoride which volatilizes at 1291° C, and this significantly reduces the spectral interference. The use of 0.5 mL of concentrated hydrofluoric acid and 4 mL of concentrated trace metal grade nitric acid and 0.25 g of sample enabled accurate and precise determination of arsenic in saline matrices containing aluminum up to 0.053 M Al 3+ with LOD and LOQ varying with amount of hydrofluoric acid used.;Furthermore, since mobility and toxicity of arsenic and selenium in natural waters are related to the aqueous species distribution, a Diffusive Gradients in Thin Film technique (DGT) employing a polyacrylamide diffusive gel or 3-mecarptopropyl-functionalized silica and high-capacity nanocrystalline titanium (IV) oxide adsorbent (Metsorb) has been modified and used to isolate the bioavailable analytes species and thereby minimize the matrix effects observed in quantitation by graphite furnace atomic absorption spectroscopy (GFAAS). The DGT-GFAAS procedure has been used to determine the bioavailable arsenic and selenium isolated from flowback water from an actual gas well drilling operation (WRF6), as well as spiked samples of WRF6 and flowback wastewater (FS1). In addition, Marcellus shale samples were exposed to WRF6 for varying lengths of time and DGT-GFAAS was used to determine the bioavailable arsenic and selenium in these solutions. Speciation analysis was also carried out. The elution efficiencies using 1 M sodium hydroxide for arsenic and selenium were between 80--93% and the detection limit for arsenic and selenium for 3 day deployments based on the standard deviation of the blank were 0.064 and 0.10 microg/L, respectively

    SOCIAL FRANCHISING IN CONTEXT OF MARKETING LONG-TERM AND REVERSIBLE CONTRACEPTIVES (LARCS) IN UGANDA: ANALYSIS OF PACE SOCIAL FRANCHISE MODEL

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    Background: Uganda is TFR is among the world’s highest at six children per woman, and contributes to the rising rate of poverty and maternal and infant mortality across the country. A social franchise model was adopted in Uganda to market and scale up contraceptive prevalence through the private sector. In 2008 PACE launched the Women’s Health Project, a core component of their reproductive health strategy to increase access to and demand for affordable, quality long‐term Family Planning (FP) services, through the setup of a network of private healthcare providers, branded as “ProFam” social franchise health facilities. The program expanded and included services aimed to offer and improve reproductive health services, limiting births through increased use of IUDs and implants as well change negative perceptions to FP. Until 2014, this network consisted of 189 private facilities spread out in 56 districts, following a business model of social franchising. Methods: The multifaceted effect of the social franchise intervention under PACE was then measured through a longitudinal cross sectional survey on perceptions towards Long-Term and Reversible Contraceptives (LARCs) use among the target population through a cross-sectional studies over two periods. The studies covered 53 districts hosting 194 privately owned health facilities branded Profam. Multi-stage cluster sampling approaches was used to draw a representative sample of women of reproductive age group. However, for Kampala (capital city), given its population size, the catchment area was restricted to a parish/Ward. Findings: There is an evident rise in current use of FP methods among WRA. Availability of LARCs particularly IUCDs significantly increased over the two time periods. Use of FP services among WRA is a socially sanctioned behavior/practice. There was reported increase in social support for FP services. There were high levels of correct knowledge about FP services and methods, particularly LARCs and outcome expectations from FP increased Conclusion: There is an opportunity for increasing uptake of LARCs especially IUDS and Implants through the private sector via a social franchising model. Further, positive changes have been registered in the campaign to mutate negative perceptions against LARCs suggesting positive effect of increasing service accessibility within the community of the target group in easily accessible outlets within the network

    Integrating local knowledge with tree diversity analyses to optimize on-farm tree species composition for ecosystem service delivery in coffee agroforestry systems of Uganda

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    Coffee agroforestry systems deliver ecosystem services (ES) critical for rural livelihoods like food but also disservices that constrain livelihoods like fostering coffee-pests. Since such ES are tree-based, maximizing ES and limiting constraints requires knowledge on optimizing on-farm tree composition especially trees adapted to local conditions. The study was in three sites along a rainfall gradient in Central Uganda where we: assessed tree diversity in coffee agroforestry; ranked tree suitability for providing ES according to farmers' knowledge; and then proposed an approach for optimizing on-farm tree composition for delivery of ES. We collected data on tree diversity and, farmers' knowledge of tree species and the ES they provide. Farmers ranked ES in order of importance to their livelihoods ('Needs rank') and ranked trees according to suitability for providing ES. Using Bradley Terry modeling, we grouped trees into 'ES groups' according to suitability for providing different ES and ranked 'ES groups' according to tree diversity ('Diversity rank'). Tree-suitability for providing ES and importance of ES to farmers varied with rainfall regime but tree diversity did not match farmers' needs for ES. We propose the FaD–FaN (matching farm tree diversity to farmers' needs) approach for optimizing tree species composition with respect to tree-suitability for farmers' priority ES. Farmers locally prioritize ES needed and identify trees that best serve such ES. The approach then focuses on modifying on-farm tree diversity to match/suit farmers' priority ES. The FaD–FaN approach caters for varying socio-ecological conditions; it's adaptable for other coffee and cocoa-growing areas worldwide

    Chaotic Rivest-Shamir-Adlerman Algorithm with Data Encryption Standard Scheduling

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    Cryptography, which involves the use of a cipher, describes a process of encrypting information so that its meaning is hidden and thus, secured from those who do not know how to decrypt the information. Cryptography algorithms come with the various types including the symmetric key algorithms and asymmetric key algorithms. In this paper, the authors applied the most commonly used algorithm, which is the RSA algorithm together with the Chaos system and the basic security device employed in the worldwide organizations which is the Data Encryption Standard (DES) with the objective to make a hybrid data encryption. The advantage of a chaos system which is its unpredictability through the use of multiple keys and the secrecy of the RSA which is based on integer factorization’s difficulty is combined for a more secure and reliable cryptography. The key generation was made more secure by applying the DES schedule to change the keys for encryption. The main strength of the proposed system is the chaotic variable key generator that chages the value of encrypted message whenever a different number of key is used. Using the provided examples the strength of security of the proposed system was tested and demonstrated

    Chaotic Rivest-Shamir-Adlerman Algorithm with Data Encryption Standard Scheduling

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    Cryptography, which involves the use of a cipher, describes a process of encrypting information so that its meaning is hidden and thus, secured from those who do not know how to decrypt the information. Cryptography algorithms come with the various types including the symmetric key algorithms and asymmetric key algorithms. In this paper, the authors applied the most commonly used algorithm, which is the RSA algorithm together with the Chaos system and the basic security device employed in the worldwide organizations which is the Data Encryption Standard (DES) with the objective to make a hybrid data encryption. The advantage of a chaos system which is its unpredictability through the use of multiple keys and the secrecy of the RSA which is based on integer factorization's difficulty is combined for a more secure and reliable cryptography. The key generation was made more secure by applying the DES schedule to change the keys for encryption. The main strength of the proposed system is the chaotic variable key generator that chages the value of encrypted message whenever a different number of key is used. Using the provided examples the strength of security of the proposed system was tested and demonstrated
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