182 research outputs found
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
A MODIFIED SFS ALGORITHM BASED ON STEREO IMAGES FOR THE THREE-DIMENSION RECONSTRUCTION OF URBAN BUILDINGS
No full textThe blind areas of two adjacent aerial images are usually large in Urban Remote Sensing, in order to reconstruct three-dimensional (3D) information of the building in these blind areas, a new modified SFS algorithm based on stereo images is proposed. This SFS algorithm is utilized to reconstruct object surface gradient information (relative elevation) of buildings in the overlapping areas based on the grey information of the image. The absolute elevation information could be gained by the stereo images which had been already finished relative orientation and absolute orientation. The fitting transformational relationship is set up between the relative and absolute elevation information of the characteristic ground points in these overlapping areas with Least Square Method. The building 3D information in non-overlapping domain can be reconstructed by this transformational relation. From the experiment results, it is found that the stereo models reconstructed by the modified SFS algorithm based on stereo images are better and have lower distortions than those reconstructed by general SFS algorithm.Geosciences, MultidisciplinaryRemote SensingEICPCI-S(ISTP)
Standardissa SFS-EN 45545 asetetut palamiskäyttäytymisvaatimukset kiskokalustossa käytettäville materiaaleille ja komponenteille
No full textVuoden 2017 jälkeen käyttöönotettavissa Euroopan unionin rautatiejärjestelmässä liikennöivissä vetureissa ja henkilöliikenteen vaunuissa käytettävien materiaalien ja komponenttien tulee täyttää standardissa SFS-EN 45545-2 (Kiskoliikenne. Palotorjunta kiskoajoneuvoissa. Osa2: Materiaalien ja komponenttien palamiskäyttäytymisvaatimukset.) asetetut palamiskäyttäytymisvaatimukset. Työn tavoitteena oli laatia standardista ja siinä palamiskäyttäytymisen tutkimiseen määritetyistä testimenetelmistä kirjallinen selostus, jota voidaan käyttää helposti materiaalina tutustuessa materiaaleille ja komponenteille asetettuihin palamiskäyttäytymisvaatimuksiin ja palamiskäyttäytymisen arvioimiseen. Työn tavoitteena oli myös laatia kaksikerrosvaunussa käytetyistä komponenteista lista, josta selviää mitä testejä komponenteille tulee tehdä. Työ tehtiin Transtech Oy:lle.
Työssä tutustuttiin palamisteoriaan, palamistuotteiden muodostumiseen, tulipalon kehittymiseen, paloturvallisuuteen, evakuointiin sekä palotestaukseen yleisesti. Työssä tutustuttiin myös Transtech Oy:n valmistamaan kiskokalustoon, kiskoajoneuvo-onnettomuuksiin, Euroopan unionin rautatiejärjestelmää ja siinä liikennöiviä kiskoajoneuvoja koskeviin turvallisuusmääräyksiin sekä aiheeseen liittyviin standardeihin. Standardeista SFS-EN 45545-1 ja SFS-EN 45545-2 sekä vuoden 2017 loppuun asti sovellettavasta standardista DIN 5510-2 kirjoitettiin kuvaukset, joista selviää standardien pääkohdat. Standardissa SFS-EN 45545-2 määritetyistä testimenetelmistä kirjoitettiin myös kuvaukset, joista käy ilmi, mitä ominaisuutta kullakin testimenetelmällä testataan, millaisia tuotteita testimenetelmillä voi testata ja millaisia testikäytännöt ovat. Työssä tutustuttiin kaksikerrosvaunun rakenteeseen ja siinä käytetyistä komponenteista tehtiin listaus.
Työn tuloksena saatiin kirjallinen selostus, jota työn tilaajayritys voi jatkossa hyödyntää perehdyttäessä työntekijöitä aiheeseen. Selostuksesta käy ilmi, millaisia palamiskäyttäytymisvaatimuksia materiaaleille ja komponenteille asetetaan ja millaisia palotestejä niille tulee tehdä. Selostusta voidaan käyttää pääosin vain kiskokaluston suunnittelun yhteydessä, koska käsitellyt vaatimukset koskevat vain kiskokalustoa. Tehdystä komponenttilistauksesta voidaan selvittää helposti, millaisia testejä komponenteille tulee tehdä. Lisäksi listaa voidaan käyttää tarkistuslistana, johon merkitään, onko vaadittavat testit tehty ja onko niitä läpäisty.Fire behaviour of materials and components used in locomotives and passenger railway vehicles which will be brought into use after the year 2017 and which will be used in the European Union rail system should meet the requirements set in the standard SFS-EN 45545-2 (Railway Applications. Fire Protection on Railway Vehicles. Part 2: Requirements for fire behaviour of materials and components). The aim of the thesis project was to write a representation of the standard and the test methods defined in the standard. The representation can be used to become acquainted with fire behaviour requirements set to the materials and components and assessment of fire behaviour of materials and components. The aim of the thesis project was also to compile the list of the components used in the double deck coach. From the list becomes clear which tests needs to be done to the components. The thesis project was made for Transtech Oy.
The author of the thesis became familiar with the theory of combustion, formation of combustion products, fire development, fire safety, evacuation and fire testing. The author also became familiar with railway vehicles manufactured by the client company, railway vehicle incidents, safety regulations concerning the European Union rail system and railway vehicles used in it and with standards concerning the subject. Descriptions were written from the standards SFS-EN 45545-1 and SFS-EN 45545-2 and also from the standard DIN 5510-2 that is applied at the end of year 2017. Descriptions deal with essentials of the standards. Descriptions from the test methods defined in the standard SFS-EN 45545-2 were also written. The author also became familiar with the structure of the double deck coach and the list of the components used in it was complied.
Outcome of the thesis project was the written representation and the component list. The written representation can be used to get employees become acquainted with the subject. Fire behaviour requirements of materials and components and required test methods are described in the representation. The representation can be mainly used when designing railway vehicles because discussed requirements concern only railway vehicles. From the component list it is easy to look up which tests need to be done for each component. It is possible to use the component list as a checklist and mark if the required tests have been carried out and whether they are passed
Sustainable business models for smallholder farmers:: Challenges for and lessons from the Barsha pump experience
No full textSmallholder farmers (SFs) are cornerstone actors in eradicating poverty and hunger. Companies have recently focused on SFs as potential customers and suppliers. Several hindrances yet prevent SFs to be commercially viable actors. In this respect, sustainable business models (SBMs) bring opportunities for companies to increase profit, improve SFs' livelihoods, and promote environmental sustainability. Recognizing these opportunities, the Dutch company aQysta provides the Barsha pump (BP) as a sustainable irrigation solution for SFs. The challenges for BP adoption that remain for SFs illustrate that there is still limited understanding of how SBMs can support companies in engaging with SFs. To expand this understanding, we conducted a multiple-case analysis of 10 organizations providing SF-tailored products and/or services. Based on this analysis, we have drawn lessons for aQysta (and similar companies) to improve the BP's value proposition and we elaborate on the implications of this study for other organizations engaging commercially with SFs.Water ResourcesDesign for Sustainabilit
Fire behaviour requirements of materials and components used in railway vehicles according to the standard SFS-EN 45545
No full textVuoden 2017 jälkeen käyttöönotettavissa Euroopan unionin rautatiejärjestelmässä liikennöivissä vetureissa ja henkilöliikenteen vaunuissa käytettävien materiaalien ja komponenttien tulee täyttää standardissa SFS-EN 45545-2 (Kiskoliikenne. Palotorjunta kiskoajoneuvoissa. Osa2: Materiaalien ja komponenttien palamiskäyttäytymisvaatimukset.) asetetut palamiskäyttäytymisvaatimukset. Työn tavoitteena oli laatia standardista ja siinä palamiskäyttäytymisen tutkimiseen määritetyistä testimenetelmistä kirjallinen selostus, jota voidaan käyttää helposti materiaalina tutustuessa materiaaleille ja komponenteille asetettuihin palamiskäyttäytymisvaatimuksiin ja palamiskäyttäytymisen arvioimiseen. Työn tavoitteena oli myös laatia kaksikerrosvaunussa käytetyistä komponenteista lista, josta selviää mitä testejä komponenteille tulee tehdä. Työ tehtiin Transtech Oy:lle.
Työssä tutustuttiin palamisteoriaan, palamistuotteiden muodostumiseen, tulipalon kehittymiseen, paloturvallisuuteen, evakuointiin sekä palotestaukseen yleisesti. Työssä tutustuttiin myös Transtech Oy:n valmistamaan kiskokalustoon, kiskoajoneuvo-onnettomuuksiin, Euroopan unionin rautatiejärjestelmää ja siinä liikennöiviä kiskoajoneuvoja koskeviin turvallisuusmääräyksiin sekä aiheeseen liittyviin standardeihin. Standardeista SFS-EN 45545-1 ja SFS-EN 45545-2 sekä vuoden 2017 loppuun asti sovellettavasta standardista DIN 5510-2 kirjoitettiin kuvaukset, joista selviää standardien pääkohdat. Standardissa SFS-EN 45545-2 määritetyistä testimenetelmistä kirjoitettiin myös kuvaukset, joista käy ilmi, mitä ominaisuutta kullakin testimenetelmällä testataan, millaisia tuotteita testimenetelmillä voi testata ja millaisia testikäytännöt ovat. Työssä tutustuttiin kaksikerrosvaunun rakenteeseen ja siinä käytetyistä komponenteista tehtiin listaus.
Työn tuloksena saatiin kirjallinen selostus, jota työn tilaajayritys voi jatkossa hyödyntää perehdyttäessä työntekijöitä aiheeseen. Selostuksesta käy ilmi, millaisia palamiskäyttäytymisvaatimuksia materiaaleille ja komponenteille asetetaan ja millaisia palotestejä niille tulee tehdä. Selostusta voidaan käyttää pääosin vain kiskokaluston suunnittelun yhteydessä, koska käsitellyt vaatimukset koskevat vain kiskokalustoa. Tehdystä komponenttilistauksesta voidaan selvittää helposti, millaisia testejä komponenteille tulee tehdä. Lisäksi listaa voidaan käyttää tarkistuslistana, johon merkitään, onko vaadittavat testit tehty ja onko niitä läpäisty.Fire behaviour of materials and components used in locomotives and passenger railway vehicles which will be brought into use after the year 2017 and which will be used in the European Union rail system should meet the requirements set in the standard SFS-EN 45545-2 (Railway Applications. Fire Protection on Railway Vehicles. Part 2: Requirements for fire behaviour of materials and components). The aim of the thesis project was to write a representation of the standard and the test methods defined in the standard. The representation can be used to become acquainted with fire behaviour requirements set to the materials and components and assessment of fire behaviour of materials and components. The aim of the thesis project was also to compile the list of the components used in the double deck coach. From the list becomes clear which tests needs to be done to the components. The thesis project was made for Transtech Oy.
The author of the thesis became familiar with the theory of combustion, formation of combustion products, fire development, fire safety, evacuation and fire testing. The author also became familiar with railway vehicles manufactured by the client company, railway vehicle incidents, safety regulations concerning the European Union rail system and railway vehicles used in it and with standards concerning the subject. Descriptions were written from the standards SFS-EN 45545-1 and SFS-EN 45545-2 and also from the standard DIN 5510-2 that is applied at the end of year 2017. Descriptions deal with essentials of the standards. Descriptions from the test methods defined in the standard SFS-EN 45545-2 were also written. The author also became familiar with the structure of the double deck coach and the list of the components used in it was complied.
Outcome of the thesis project was the written representation and the component list. The written representation can be used to get employees become acquainted with the subject. Fire behaviour requirements of materials and components and required test methods are described in the representation. The representation can be mainly used when designing railway vehicles because discussed requirements concern only railway vehicles. From the component list it is easy to look up which tests need to be done for each component. It is possible to use the component list as a checklist and mark if the required tests have been carried out and whether they are passed
Fatalism and well-being across hispanic cultures: the Social Fatalism Scales (SFS)
No full textThe author may only post his/her version provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be provided by inserting the DOI number of the article in the following sentence: “The final publication is available at Springer via http://dx.doi.org/[insert DOI]”Fatalism has been a core construct in the study of psychological and social processes related to well-being and life quality in social sciences. The objective of the present
research is to develop a new instrument, the Social Fatalism Scales (SFS), which allows us to study the influence of individualist and collectivist fatalism on well-being across Hispanic cultures. The parallel and exploratory factor analyses suggest a multidimensional structure composed by four factors (Study 1). Confirmatory factor analysis showed that this four-factor structure is adjusted perfectly to the data (Study 2). All the SFS presented an adequate reliability in the two examined samples. As expected, fatalism in an individualist culture (Spanish sample) negatively correlated with subjective well-being and social well-being indicators. However, in a collectivist sample (Colombian), fatalism was negatively related to social and psychological well-being but positively to subjective well-being. In collectivist cultures, social fatalism is manifested as a useful strategy to adapt to certain aspects of life.This research was supported by Ministry of Economy and Competitiveness—Government of Spain (PSI2012-37808) and Spanish Agency for International Development Cooperation (C03070610)
Experimental Scheduling Functions for Global LPV Human Controller Modeling
No full textIn this paper, the Linear Parameter Varying (LPV) model identification framework is applied to estimating time-varying human controller (HC) dynamics in a single-loop tracking task. Given the inherently unknown time changes in HC behavior, a global LPV approach with experimentally determined Scheduling Functions (SFs) is needed for this application. In this paper, a methodology based on the Predictor-Based Subspace Identification (PBSID) algorithm is tested. Using Monte Carlo simulation data matching a recent experimental study, two experimental SFs derived from measured HC control inputs are tested for their LPV model identification performance. The results are compared with LPV models obtained using the true (analytical) SFs used for generating the simulation data. An experimental SF obtained from the double derivative of HCs’ control inputs using zero-phase low-pass filtering was found to yield time-varying HC model estimates of equivalent accuracy as obtained with the analytical SFs; a promising result for future application of this methodology to measured HC behavior.Control & SimulationControl & Operation
Monitoring the characteristics and removal of natural organic matter fractions in selected south african water treatment plants
No full textThis study used spectroscopic methods to investigate the fate and dynamics of natural organic matter (NOM) as it traverses the treatment train at three water treatment plants (WTPs) in South Africa. The character, quantity, and removability of NOM at specific treatment stages was investigated by measuring changes in dissolved organic carbon (DOC) concentration, specific ultra-violet absorbance, UV absorbance, various spectroscopic indices, and maximum fluorescence intensity levels. A novel method of identifying and quantifying fluorescent fractions by combining synchronous fluorescence spectroscopy (SFS) and Gaussian peak fitting is presented. The dynamics of NOM removal were modeled using 2D-SFS correlation spectroscopy. Humic and fulvic substances dominated coastal plants and were the most amenable for removal by coagulation as shown by Hermanus WTP (plant H), which had a 42% DOC removal at the coagulation stage. Tyrosine-like, tryptophan-like and microbial humic-like substances were degraded or transformed concurrently at plant Flag Bushiole (FB) whereas, at plant H, fulvic-like matter was transformed first followed by tyrosine-like then humic-like matter. Through 2D-SFS, this study revealed that NOM transformation was varied as a consequence of NOM character, the type and dosage of treatment chemicals used, and WTPs operational parameters.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin
Irrigation technology at the service of smallholder farmers: A sociotechnical approach to exploring sustainable business strategies
No full textRecently, there has been a growing need for sustainable agriculture to increase food security, alleviate poverty, and contribute to climate change mitigation. Smallholder farmers (SFs) play a key role in this endeavor as they are a considerable segment of the global farming population. Despite their relevance, SFs face several challenges that hinder their productivity and compromise their livelihoods. Among the most salient challenges are limited access to (financial) resources and technology, insufficient knowledge and training, limited market access, and climate change vulnerability. Social and gender inequalities, land tenure insecurity, underdevelopment of supply chains, and lack of supportive policies further exacerbate these challenges.Innovations of different kinds can support SFs in transforming agricultural systems towards the accomplishment of several sustainable development goals. These innovations can take the form of new technologies, new farming practices, social and collective empowerment, and systemic changes at policy and regulatory levels. In this context, and responding to the pressing issue of SFs’ development, the Dutch company aQysta developed a hydro powered water lifting device, known as the Barsha pump (BP). aQysta offers this technology as an innovative and sustainable solution to the irrigation challenges facing SFs. The BP operates solely on renewable energy, meaning that no input of fossil fuels is required to use it. aQysta argues that these features make the BP both an environmentally sound and affordable irrigation solution, with the potential of improving the livelihoods of SFs. In consonance with those claims, the BP represents a promising technological advancement that aligns well with the sustainable development of SF systems. Technology provider companies typically resort to business models as strategic blueprints to create, deliver, and capture value. This has been largely the case of aQysta and its deployment of the BP across several SF communities. However, when it comes to technological innovations for SFs, traditional business models typically fall short in these purposes due to the several challenges of the SF target customers. By incorporating social inclusion and environmental stewardship strategies (besides legitimate profit generation), sustainable business models (SBMs) can support more robustly companies aiming to serve SFs like aQysta.In this respect, by focusing on aQysta’s technology proposition, this thesis investigates a) how innovative agricultural technologies cater for the needs of SFs, b) how SFs decide to adopt such innovative agricultural technologies, and how SFs’ contexts play a key role in that decision, and, c) how SBMs can support technology providers in delivering their value propositions to their target SFs. Through an interdisciplinary approach—with aspects of engineering, entrepreneurship, and sustainable development—this study aims to shed light on the intricate relationship between technologies, SBMs, and SF’s social impact, through the following main research question:What sustainable business model strategies stimulate the adoption of hydro powered pumps for smallholder irrigation?To answer this research question, I resorted to a mixed method approach applied to five studies, which correspond to the different chapters of this thesis. These five studies compose this dissertation by analyzing the main research question from different angles: technologies, method to study SF phenomena, farmer’s decision making, SFs’ technology adoption, and SBM strategies to cater for SFs’ needs.I started by reviewing the range of available hydro powered pumping technologies over time (Chapter 2). To this end, I conducted a semi systematic literature review of more than 800 scientific and grey documents. These documents addressed the fragmented storylines of several technologies, from their conceptualization and design to their eventual (mass) production and commercialization worldwide. I classified and plotted a total of 30 pumping technologies in space and time. Some noticeable clusters emerged in regions like Europe, South–Southeast Asia, and Eastern Africa, around 1960 – 1990. Some of the studied technologies had a global impact until contemporary times, others have been key in specific countries, and other ones had almost imperceptible lives. I found that hydro powered pumping technologies currently face a regained momentum, hence a potentially promising future. However, manufacturers and users need to be aware of the importance that proper management systems pose for these technologies beyond their mere performance.Then, I analyzed the potential of Q methodology (henceforth Q) as a sound participatory research method to understand SF’s phenomena (Chapter 3). To reach the goal of this study, I selected and reviewed 50 Q studies applied to different forms of rural livelihoods in the Global South. In this chapter first I discuss several on field Q limitations associated with the physical, logistical, social, and cultural constraints of such settings. Later, I drew on good practices and strategies to cope with these limitations. Beyond the limitations and strategies, I advocate building Q capacities and the gender balanced empowerment of local researchers in the Global South. This may contribute to a better understanding of the nuances and challenges of SF’s livelihoods in their respective contexts.Through a co authored study, I later researched farmers’ decision making strategies through the lens of Q (Chapter 4). We used Q to delve into Malawian farmers’ decision to adopt certain water transport technologies for irrigation. The method was administered face to face to several SFs, large commercial farmers, representatives of farmer cooperatives, and experts in farming systems in Malawi. We found that SFs, typically considered a homogeneous group, did not decide in the same ways. Some SFs, in fact, may have progressive and commercial mindsets that can be hampered by lack of access to required resources. Furthermore, our results showed that decision making has a clear gender dimension. We found Q to be a robust methodology, capable of capturing several nuances of farmers’ decision making.Later, I focused on the specific SFs’ decision (or not) to adopt the BP in its intended contexts of use (Chapter 5). By means of Q, I explored cross cultural discourses around the adoption of BP. I administered Q to 43 (non )farmer respondents linked to Nepali and Indonesian SF systems. I identified three relevant discourses, one of them bipolar in nature. The first one identified BP’s potential early adopters. The second discourse embodied the stereotypically highly dependent SF. The last one characterized contrasting views around the BP as an enabler of potential service oriented business models to achieve well being. These results reflect the need for a shift of mindset toward new ways of understanding technological change in SF settings. Based on my findings, I proposed possible technology adoption pathways that may lead to the exploration of innovative business models to serve the diversity of SFs more effectively.Lastly, I conducted a study on SBM strategies to cater better to the specific needs of SFs (Chapter 6). I used a multiple case analysis to expand the knowledge on this incipient research area. For this analysis, I considered the cases of 10 organizations providing SF tailored products and/or services. I conducted the cross case analysis stage across five thematic areas relevant to SF’s challenges: information and knowledge, capital and financial services, training and capacity building, rural logistics and supply chains, and market connection. Based on the results of the analyses, I drew lessons for aQysta (and similar companies) to improve BP’s value proposition. I also elaborated on the implications of the study for other organizations engaging commercially with SFs.Building on the findings of these five individual studies, I was able to identify SBM strategies to stimulate the adoption of hydro powered pumps for SF irrigation. I present these strategies in the concluding section of this thesis (Chapter 7) by following the five SBM thematic areas (identified in Chapter 6) across the four SFs discourses on the BP adoption (studied in Chapter 5). Proposed strategies cover SFs’ issues related to: information content and delivery channels; provision of capital and financial services; approaches to deliver training and build SF capacities; approaches to build robust and sustainable last mile networks to reach SFs; and market connection to increase SFs’ commercial viability to foster technology adoption. Finally, I close my doctoral dissertation discussing the implications of my findings and proposed strategies for different actors involved in SF’s technology adoption: researchers, technology developers, practitioners, and policymakers.Water Resource
Administrative and legal principles for improving the activities of the institution of internal security of the SFS
No full textУ науковому виданні авторським колективом досліджено правовий статус Головного управління внутрішньої безпеки як самостійного структурного підрозділу Державної фіскальної служби України та оперативного підрозділу податкової міліції. З урахуванням досвіду США, країн ЄС, Республіки Казахстан у сфері організації внутрішньої безпеки в органах доходів і зборів запропоновано Програму дій з реформування інституції внутрішньої безпеки ДФС України. Висвітлено застосування ризик-менеджменту в діяльності інституції внутрішньої безпеки органів ДФС, корупційні ризики як складову інституційних ризиків, зокрема у сфері дискреційних повноважень. Запропоновано рекомендації щодо запровадження автоматизованих аналітичних платформ, на основі яких збирається, аналізується інформація щодо виявлення корупційних ризиків та здійснюється управління ними.
In the scientific publication, the author's team investigated the legal status of the Main Department of Internal Security as an independent structural unit of the State Fiscal Service of Ukraine and an operational unit of the tax police. Taking into account the experience of the USA, EU, Kazakhstan in the field of internal security in the bodies of revenues and fees, was proposed a Program of Action to reform the internal security institution of the SFS of Ukraine. The application of risk management in the activities of the internal security institution of the SFS is highlighted. Corruption risks as a component of institutional risks, in particular in the area of discretionary powers. Recommendations for the introduction of automated analytical platforms are proposed, on the basis of which information on the detection of corruption risks is collected, analyzed and managed
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