Miracle-dz/UniFAR-FTUs huggingface dataset:
Optimization for sustainable utilization of low temperature geothermal systems

Low temperature geothermal resources provide hot water that is commonly used for space heating and various applications. A geothermal resource is considered to be a renewable energy source that can be utilized by current and future generations if sustainability considerations are respected. The goal of this work is to determine if utilization of a geothermal reservoir can be optimized under sustainable operation. One way to carry out this kind of optimization is to connect reservoir and operational optimization models directly. The underlying reservoir model used here is a lumped parameter model (LPM). A LPM model can be used to simulate pressure (drawdown) changes in a low temperature reservoir with respect to harvesting levels. One scenario is to maximize the present value of profit where important parameters include production rate, water level (drawdown) and production capacity from which the profit can be calculated. Optimization over a time period subject to underlying developing constraints is often referred to as dynamic optimization. This problem is essentially a mixed integer non-linear dynamic optimization problem, often referred to as mixed integer dynamic optimization (MIDO). Three solution methods for the optimization problem are discussed, tested and compared. The parameters of the LPM are obtained by non-linear least square estimation where the LPM is essentially a simplified approach to characterize a spatially distributed reservoir. Data from four different geothermal fields are calibrated to the LPM, validated with split validation and the best calibrations chosen for the optimization application. Profit is first maximized assuming long-term production based on demand from historical data. Different performance indices for the geothermal utilization are then optimized and various scenarios are considered and compared under annually increased demand. %%%%Laghitajarðvarmasvaeði eru auðlindir sem gera það kleift að heitt vatn se nýtt til hushitunar fyrir heimili eða margskonar atvinnustarfsemi. Jarðvarmi er talin vera endurnýjanleg auðlind sem komandi kynsloðir munu geta nýtt ser að þvi tilskildu að sjalfbaer nýting se hofð að leiðarljosi. Markmiðið með þessu verkefni er að komast að þvi hvort haegt se að besta sjalfbaera nýtingu a slikri auðlind. Ein leið til að utfaera slika bestun er að tengja forðafraeðilikan beint við rekstrar-bestunar likan (e. operational optimization). Slikt likan er haegt að nota til að herma þrýstingsbreytingar (breytingar i niðurdraetti) i lagvarma jarðhitageymi (e. low temperature reservoir) með tilliti til framleiðslugetu. Taka ma fyrir tilfelli þar sem hagnaður er bestaður þar sem mikilvaegar breytur sem nota ma til að reikna hagnað eru meðal annars, framleiðslustig, vatnshaeð (niðurdrattur) og framleiðslugeta. Þegar bestað er yfir timabil með undirliggjandi breytilegri skorðu er oft talað um hreyfina bestun (e. dynamic optimization). Þetta vandamal er i eðli sinu blendin olinuleg hreyfin bestun (e. mixed integer non-linear dynamic…
Passivity-Based Control for Interleaved Double Dual Boost Converters in DC Microgrids Supplying Constant Power Loads

The interleaved double dual boost converter (IDDBC) is considered a promising and reliable approach to interface the low-voltage renewable energy sources (RESs), such as battery packs, fuel cells, and photovoltaic (PV) panels, to the dc bus of the dc microgrids. It could give a higher voltage step-up ratio and reduce voltage and current stresses on the power devices. However, the connection of various tightly regulated power converters, which are known as constant power loads (CPLs), would cause negative incremental impedance. Meanwhile, the unmodeled dynamics and load perturbation disturbances are unavoidable in the dc microgrid. These issues would deteriorate the system stability and even lead to system failure. To address these problems, this article proposes an adaptive passivity-based control (PBC) to handle the dc bus’s large-scale stability issues of the $N$ -phase IDDBC feeding CPL system. A reduced and practical $N$ -phase IDDBC model supplying CPL considering unmodeled dynamics and load perturbation disturbances is proposed to facilitate the controller design. Besides, a nonlinear disturbance observer (NDO) is incorporated with the proposed PBC to improve the robustness against parameter uncertainties and external disturbances. And the global stability of the closed-loop system is proved through the Lyapunov theorem. Finally, simulation and experimental results are demonstrated to verify the feasibility and effectiveness of the proposed controller.
Manure matters: prospects for regional banana-livestock integration for sustainable intensification in South-West Uganda

ABSTRACT In South-West Uganda, manure is highly valued for sustaining yields of East African Highland Banana, but it is in short supply. As a result, banana growers import manure from rangelands up to 50 km away. We aimed to explore the potential of this regional banana-livestock integration to meet crop nutrient requirements for sustainable intensification of banana cropping systems. We used a mixed-methods approach supported by detailed data collection. Multiple spatial levels were integrated: field-level modelling to determine long-term nutrient requirements, a household-level survey to characterize farmer practices, and a regional-level spatial analysis to map banana production and manure source areas. For median to 90th percentile banana yields (37-52 t FW/ha/year), minimum K requirements were 118–228 kg/ha/year. To supply this with manure, 10.5–20.5 t DM manure/ha/year would be needed, requiring 47–91 tropical livestock units and 27–52 ha of rangeland, far more than what is potentially available currently. However, using only manure to satisfy potassium requirements increases the risk of N losses due to nutrient imbalances likely to result from large manure applications. For sustainable intensification, manure supplemented with K-based fertilizers is a better option than manure alone, as it is more cost-effective and reduces potential N losses.
Using a structured approach to authoring OER content: An evaluation of two cases

The Teacher Education in Sub Saharan Africa (TESSA) OER materials are a response to the teacher crisis in many developing countries, with millions of unqualified teachers entering the classroom ( See www.tessafrica.net ). The TESSA teacher professional development materials were developed by a collaboration of eighteen institutions and are currently being used by about 300 000 teachers across nine African countries. To ensure that the resources were appropriate and relevant, these OERs followed an agreed common template for construction with the intention to facilitate versioning for the different school contexts, in four languages. OpenLearn ( See www.open.ac.uk/openlearn ) is an OER site containing over 10 000 hours of learning materials from the UK Open University. With well over five million unique visitors, its purpose was to showcase the Universities materials, to attract new students and to investigate new possibilities in the creation of new course content. It too was created around a template as shown by the OpenLearn module ‘Creating Open Educational Resources’ (http://openlearn.open.ac.uk/course/view.php? id=3636 . The Open University took a leading role in the development of both TESSA and OpenLearn. Using these as case studies, this paper analyses the systemic organisational benefits and constraints of a structured template approach to OER content production. It seems that such an approach is successful – both the TESSA and OpenLearn OER sites have won prestigious awards. However, this structured methodology for OER content production is considered particularly in relation to: • The level of support needed by authors new to creating OERs • The cost-benefits of production; • The speed of creation and re-creation; • The way cultural norms impact on notions of ‘ownership’, ‘sharing’ and ‘adapting’ the work of others; It is suggested that making the construction template more explicit would encourage greater contribution to Open Educational Resources (OERs).
1H HR-MAS NMR Based Metabolic Profiling of Lung Cancer Cells with Induced and De-Induced Cisplatin Resistance to Reveal Metabolic Resistance Adaptations

Cisplatin (cisPt) is an important drug that is used against various cancers, including advanced lung cancer. However, drug resistance is still a major ongoing problem and its investigation is of paramount interest. Here, a high-resolution magic angle spinning (HR-MAS) NMR study is presented deciphering the metabolic profile of non-small cell lung cancer (NSCLC) cells and metabolic adaptations at different levels of induced cisPt-resistance, as well as in their de-induced counterparts (cells cultivated in absence of cisPt). In total, fifty-three metabolites were identified and quantified in the 1H-HR-MAS NMR cell spectra. Metabolic adaptations to cisPt-resistance were detected, which correlated with the degree of resistance. Importantly, de-induced cell lines demonstrated similar metabolic adaptations as the corresponding cisPt-resistant cell lines. Metabolites predominantly changed in cisPt resistant cells and their de-induced counterparts include glutathione and taurine. Characteristic metabolic patterns for cisPt resistance may become relevant as biomarkers in cancer medicine.
Design and demonstration of a biomimetic wing section using lightweight piezoceramic composite actuator (LIPCA)

Biomimetic wing sections actuated by piezoceramics actuator LIPCA have been designed and their actuation displacements estimated by using the thermal analogy and MSC/NASTRAN based on the linear elasticity. The wing sections are fabricated as the design and tested for evaluation. Measured actuation displacements were larger than the estimated values mainly due to the material non-linearity of the PZT wafer. The biomimetic wing sections can be used for control surfaces of small scale UAVs.
Modeling and tuning security from a quality of service perspective

Security has traditionally been thought of as a system or network attribute that was the result of the joint endeavors of the designer, maintainer and user, among others. Even though security can never reach a level of 100%, the aim has been to provide as much security as possible, given the boundary conditions in question. With the advent of, e.g., many low-power computing and communication devices it has become desirable to trade security against other system parameters, such as performance and power consumption. Thus, in many situations, tunable or selectable security, rather than maximal security, is desirable. The overall focus of this thesis is therefore how security with tunable level could be achieved and traded against other parameters. To this end, basic security primitives, such as the intrusion process, flaws, and impairments, are studied. This contributes to a deeper understanding of fundamental problems and paves the way for security modeling. This part of the work provides a great deal of experimental data that are also used for modeling purposes. Attempts to model and systemize security are made based on the knowledge thus achieved. The relation between security and dependability is touched upon, and the physical separation to achieve certain desirable security properties is pointed out. However, most of the modeling research is devoted to suggesting methods for achieving different security levels, i.e., tuning security, in particular for networked applications. Here, the widespread Quality of Service (QoS) concept turns out to be a proper means to embed this novel concept, and a taxonomy for tunable data protection services is suggested. Two data protection services are developed in order to test and verify the concept of tunable security. The evaluations are limited to networked applications and confidentiality through selective encryption schemes. The tests show good agreement between experimental and theoretical results. It is clear that the future applications will require security that can be set to a desired level in order to optimize total system performance. This thesis shows that this is possible and gives some ideas as to how selectable security can be generally attainable.
STRATEGIC AND OPERATIONAL FOCUS OF HEALTH PREVENTION IN PRIVATE AND PUBLIC SECTOR ORGANISATIONS

In this paper, with a view to the high levels of absence due to sickness and presenteeism, it is explored how management and team leadership can be integrated on a more sustained basis in health prevention. Private sector enterprises on one hand, and organisations in the public sector, on the other, pursue and prioritise in this aspect different approaches, which are traceable to their different traditions. Specifically in Germany in the public sector, the principle of due care has had a long tradition that grows out of social responsibility, which contrasts with the perspective of commercial enterprises that emphasises the economic aspect. The study undertakes to determine the particular strengths of each of the sectors and to demonstrate their different approaches. The examination refers in its methodology to qualitative social research. In the systemically structured survey design, Seventy six experts were approached with questions concerning different aspects such as corporate culture, business processes, organisational integration, qualification, risk assessments, and concrete actions in health prevention. Complementary to the expert survey, documents such as corporate guidelines and policies, management tools, results from risk assessments and employee surveys or quality offensives were referred to. This analysis supplied insights on how the declared health prevention policies in an organisation can be effectively implemented at the strategic and operational level in corporate culture and leadership culture with a long-term continuity, and which organisational prerequisites in the corporate hierarchy and corporate decision making and business processes may reinforce and sustain successful implementation of health prevention. Of particular importance in the process is operative management. For the sake of effective team involvement in own and team-specific health prevention, an eight-stage team feedback was devised, which includes elements of self-reflection and perception by others in an iteratively structured process.
Generator Life and Power Electronics

The deleterious effect of full bridge rectifiers on the output of an AC generator deserves attention from the Naval community. The harmonics observed at the stator of the generator not only introduce hysteresis and eddy current losses, but voltage spikes that impact the life of the generator. The two primary factors compromising life are localized heating due to harmonics and voltage spikes that cause insulation failure through partial discharge. Induced eddy currents are proportional to frequency squared.
Stiction compensation in control valves

A procedure that compensates for static friction (suction) in control valves is presented. The compensation is obtained by adding a pulse sequence to the control signal. The characteristics of the pulse sequence are determined from the control action. Industrial field tests show that the procedure reduces the control error during stick-slip motion significantly compared to standard control without stiction compensation.
Hyperbolic S-transform-based method for classification of external faults, incipient faults, inrush currents and internal faults in power transformers

In this study, a hyperbolic S-transform-based method is proposed to discriminate most important transient fault currents of transformers. First, the proposed method discriminates external faults from other disturbances. Then, the S-transform is applied to differential currents. An index is suggested by using absolute deviations of the S-matrix of differential currents to discriminate internal incipient faults in addition to inrush currents and internal faults. The relay issues an alarm signal in the case of the incipient fault but restrains during the magnetising inrush current. If an internal fault is recognised, the relay will issue a trip signal. To study the robustness of the suggested method, a program is developed in the MATLAB environment. The inputs of this program are differential current signals, derived from a system modelled by EMTP software. In order to simulate the internal incipient fault along with internal turn to turn and turn to earth faults, the transformer is modelled as 8×8 RL matrices, derived by using subroutine BCTRAN in EMTP. Also, differential currents are contaminated by noise and it is shown that the suggested method is not affected by noise and it can discriminate incipient faults, inrush currents, internal faults and external faults.
Economic Factors Influencing Sexual Violence against Children (SVAC) in Primary Schools of Urban District, Zanzibar, Tanzania

This study was conducted to find out the economic factors influencing sexual violence against children (SVAC) in primary schools of Urban District, Zanzibar. The study used cross sectional research design based on single research approach that is qualitative approach. The study used both primary and secondary source of data collection. Primary data were collected using interviews with semi-structure checklist guide to elicit information from the sample population while secondary data were obtained through documentary reviews from books, journals, magazines, from published and un-published paper, internet sources, University of Iringa (UoI) and Zanzibar National Libraries and from other institutions and organizations dealt with sexual violence against children nationally and internationally. Purposive sampling technique was used in selecting 20 respondents and 22 key informants for this study. The collected data were analyzed using content analysis technique where by data were organized and summarized into different themes based on conceptual description of ideas. Finally, the results were presented in the form of word text narration. The study found that poverty and shortage of basic needs to the children were the economic factors influencing to the children in primary schools. Children who came from poor family failed to meet their necessity needs in right time; hence perpetrators of sexual violence used the same opportunity to perpetrate their sexual incidents to children. The study recommended that the government, Non-Governmental Organizations (NGOs), Faith Based Organizations (FBO) and community members should establish various training programs to the medias including radios and television related to good child care practicing, child rights and child protections, and monitored their child behaviour, giving them time to express their problems and needs and sharing their ideas with promotion of gender equality at all level.
Simple Technique for High-Resolution Time-Delay and Group-Velocity Measurements at Radio Frequencies

A simple technique for measuring the time delay a (modulated) radio-frequency signal experiences when passing through a medium or device is described. A carrier signal at the desired frequency is (sine) wave amplitude modulated (e. g., at 2 MHz). The modulated signal is passed through the medium or device, amplitude-detected, and compared in phase with the modulating signal from which the time delay is deduced. Time delays of a fraction of a nanosecond are easily measured.
Risk-handling styles in a context of flooding and uncertainty in Jakarta, Indonesia

Purpose – The purpose of this paper is to introduce an analytical framework to define and interpret heterogenous risk behaviour within communities facing natural hazard. By employing a combination of qualitative and quantitative methods, the paper presents a categorization of “risk-styles” that are commonly used by Jakartan riverbank settlers facing recurrent risk. Unlike the more common concept of “flood-coping strategies”, the notion of risk-styles extends the analysis of responses directly related to floods and involves a broader set of risk and poverty practices. The proposed analytical framework is likely to be useful for future research on the topic of understanding heterogenous risk behaviour, particularly for systemic comparisons of human responses to natural hazard in other parts of the world. Design/methodology/approach – The data underlying this paper were obtained during a year of extensive anthropological fieldwork in 2010 and 2011, in one of the most flood-prone riverbank settlements in Jaka.
Utilization of Industrial Rosa damascena Mill. By-products and Cocoa Pod Husks as Natural Preservatives in Muffins

Cocoa Pod Husks (CPH) and by-product from supercritical CO2 extracted Rosa damascena Mill. (RDCO2) were used as biopreservatives in muffins. Both by-products were rich source of polyphenols: 28.3 ± 0.6 mg/g Dry Weight (DW) and 17.9 ± 0.7 mg/g DW RDCO2 and CPH, respectively, and exhibited potent antioxidant capacity: 449.1 ± 8.5 µmol Trolox Equivalents (TE)/g DW (by ORAC method) and 58.9 ± 2.1 µmol Gallic Acid Equivalents (GAE)/g DW (by HORAC method) for the RDCO2, and 373.8 ± 9.0 µmol TE/g DW (by ORAC) and 36.8 ± 3.8 µmol GAE/g DW (by HORAC) for the CPH. RDCO2 extracts successfully inhibited development of several important pathogenic and saprophytic microorganisms causing microbial spoilage of food systems. The control muffins were good for consumption up to the 17th day, while the products supplemented with RDCO2 and CPH: until 20th day of storage at 22 ± 0.5 °C. The amount of dietary fibers in muffins supplemented with both by-products increased 3 times (8.57 ± 0.12 %) compared to control (2.91 ± 0.12 %) and the polyphenolic compounds increased 2.5 times (from 50.0 ± 0.3 for the control to 185.9 ± 0.6 mg/g DW). For the first time by-product of supercritical CO2 extraction of Rosa damascena Mill. was characterized and used as natural and cheap biopreservative.
Piezoelectric buckled beams for random vibration energy harvesting

Among the main vibration-to-electricity conversion systems, resonant harvesters suffer from a series of strong limits like their narrow frequency response and poor output power at small scale. Most of all, realistic vibration sources are variable in time and abundant at relatively low frequencies. Nonlinear vibration harvesters, on the other hand, are more attractive, thanks to their large bandwidth response and flexibility to convert kinetic energy of the natural frequency of the sources. In particular, bistable oscillators have been proven to show higher global performances when excited by random vibrations. In this paper, such an approach is investigated for piezoelectric beams by exerting an increasing axial compression. An advantage of this technique is the absence of magnetic forces to create bistable dynamics. A thin piezoelectric axially loaded beam is theoretically modelled and experimentally investigated under wideband random vibrations. In the buckled configuration, the device exhibits superior power generation over a large interval of resistive load, with gains up to more than a factor of ten compared to the unbuckled state. The numerical model and experimental results are in good qualitative agreement.
Evaluation of the Use of Optical Fiber Thermometers for Thermal Control of the Quench Module Insert

Issues regarding the use of optical fiber thermometers to control heater settings in a microgravity vacuum furnace are addressed. It is desirable to use these probes in environments such as the International Space Station, because they can be operated without re-calibration for extended periods. However, the analysis presented in this paper shows that temperature readings obtained using optical fiber thermometers are corrupted due to emissions from the fiber when extended portions of the probe are exposed to elevated temperatures.