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Huemer, Florian, und Andreas Steininger. „Novel Approaches for Efficient Delay-Insensitive Communication“. Journal of Low Power Electronics and Applications 9, Nr. 2 (06.04.2019): 16. http://dx.doi.org/10.3390/jlpea9020016.
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The increasing complexity and modularity of contemporary systems, paired with increasing parameter variabilities, makes the availability of flexible and robust, yet efficient, module-level interconnections instrumental. Delay-insensitive codes are very attractive in this context. There is considerable literature on this topic that classifies delay-insensitive communication channels according to the protocols (return-to-zero versus non-return-to-zero) and with respect to the codes (constant-weight versus systematic), with each solution having its specific pros and cons. From a higher abstraction, however, these protocols and codes represent corner cases of a more comprehensive solution space, and an exploration of this space promises to yield interesting new approaches. This is exactly what we do in this paper. More specifically, we present a novel coding scheme that combines the benefits of constant-weight codes, namely simple completion detection, with those of systematic codes, namely zero-effort decoding. We elaborate an approach for composing efficient “Partially Systematic Constant Weight” codes for a given data word length. In addition, we explore cost-efficient and orphan-free implementations of completion detectors for both, as well as suitable encoders and decoders. With respect to the protocols, we investigate the use of multiple spacers in return-to-zero protocols. We show that having a choice between multiple spacers can be beneficial with respect to energy efficiency. Alternatively, the freedom to choose one of multiple spacers can be leveraged to transfer information, thus turning the original return-to-zero protocol into a (very basic version of a) non-return-to-zero protocol. Again, this intermediate solution can combine benefits from both extremes. For all proposed solutions we provide quantitative comparisons that cover the whole relevant design space. In particular, we derive coding efficiency, power efficiency, as well as area effort for pipelined and non-pipelined communication channels. This not only gives evidence for the benefits and limitations of the presented novel schemes—our hope is that this paper can serve as a reference for designers seeking an optimized delay-insensitive code/protocol/implementation for their specific application.
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Luthar, Suniya S., Nina L. Kumar und Renee Benoit. „Toward fostering resilience on a large scale: Connecting communities of caregivers“. Development and Psychopathology 31, Nr. 5 (13.11.2019): 1813–25. http://dx.doi.org/10.1017/s0954579419001251.
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AbstractIn interventions for at-risk children, Tom Dishion strongly exhorted programs that are short term, cost-effective, and delivered in families’ own communities, just as resilience researchers underscore the need for programs that provide ongoing support for children's primary caregivers, and are implementable on a large scale. Presented here are preliminary results on a short-term intervention for mothers, the Authentic Connections Virtual Groups. A previous randomized trial of the in-person version of this program, conducted with mothers at high risk for stress and burnout, showed significant benefits. There had been zero dropouts across the 3-month program, and participants showed significant improvements on psychological indices as well as cortisol, even 3 months after the program ended. In the present study, virtual groups were conducted with five sets of women, all white-collar professionals with highly stressful, exacting careers, and most also primary caregivers of their children. Again, there were zero dropouts. Mean satisfaction ratings were 9.6 of 10, and the Net Promoter Score (promoters vs. detractors) fell in the “world class” range. To illuminate mechanisms of change, participants’ responses to open-ended questions on the groups’ value are presented verbatim. Recurrently mentioned were the development of new, authentic connections and invaluable ongoing support. These results, with the low costs and ease of women's attendance, attest to the value of expanding offerings such as these, toward benefiting even more highly stressed mothers themselves as well as the children for whose care they are responsible.
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Song, Zhuoyuan, Cameron Mazzola, Eric Schwartz, Ruirong Chen, Julian Finlaw, Mike Krieg und Kamran Mohseni. „A Compact Autonomous Underwater Vehicle With Cephalopod-Inspired Propulsion“. Marine Technology Society Journal 50, Nr. 5 (01.09.2016): 88–101. http://dx.doi.org/10.4031/mtsj.50.5.9.
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AbstractIn this paper, a bioinspired, compact, cost-effective autonomous underwater vehicle system is presented. Designed to operate in a heterogeneous, multivehicle collaboration hierarchy, the presented vehicle design features 3D printing technology to enable fast fabrication with a complex internal structure. Similar to a previous vehicle prototype, this system generates propulsive forces by expelling unsteady, pulsed jets, inspired by the locomotion of cephalopods and jellyfish. The novel thrusters enable the vehicle to be fully actuated in horizontal plane motions, without sacrificing the low-forward-drag, slender vehicle profile. By successively ingesting water and expelling finite water jets, periodic actuation forces are generated at all possible vehicle velocities, eliminating the need for control surfaces used in many conventional underwater vehicle designs. A semiactive buoyancy control system, inspired by the nautilus, adjusts the vehicle depth by passively allowing water flowing into and actively expelling water out of an internal bladder. A compact embedded system is developed to achieve the control and sensing capabilities necessary for multiagent interactions with the minimum required processing power and at a low energy cost. The new vehicle design also showcases an underwater optical communication system for short-range, high-speed data transmission, supplementing the conventional acoustic communication system. Experimental results show that, with the thruster motors powered at a 60% duty-cycle, the new vehicle is able to achieve a 1/4 zero-radius turn in 3.5 s and one-body-width sway translation in 2.5 s.
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Tulp, Eduard, und Laurent Siklóssy. „Searching time-table networks“. Artificial Intelligence for Engineering Design, Analysis and Manufacturing 5, Nr. 3 (August 1991): 189–98. http://dx.doi.org/10.1017/s0890060400002675.
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In this paper we present an application of AI search techniques to a class of problems that arise in transportation systems analysis. Rather than adapting the time-space network formulation typically used in Operations Research, we propose a discrete dynamic network to represent a scheduled service network. In a discrete dynamic network, there are finite, discrete, predetermined possibilities for moving from one vertex to another. Visiting a vertex has a cost (possibly zero), which may depend both on how the vertex was reached and how it will be left.We describe the DYNET search algorithm for finding optimal paths in discrete dynamic networks. DYNET has been implemented in a working system (TRAINS) which searches the entire Dutch railway services network. An optimal path in a discrete dynamic network makes us arrive at our destination as early as possible (given our planned earliest departure time), and given this earliest arrival time (eat), will allow us to leave as late as possible, thereby guaranteeing a shortest path relative to the eat. DYNET first conducts a forward search to find the earliest possible arrival time, then a backward search which uses results of the forward search, to find the latest departure to arrive at that eat. Various AI techniques (symmetries, abstraction spaces, distance estimates, etc.) improve the performance of DYNET.
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Ragab, R., B. Austin und D. Moidinis. „The HYDROMED model and its application to semi-arid Mediterranean catchments with hill reservoirs 3: Reservoir storage capacity and probability of failure model“. Hydrology and Earth System Sciences 5, Nr. 4 (31.12.2001): 563–68. http://dx.doi.org/10.5194/hess-5-563-2001.
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Abstract. This paper addresses the issue of "what reservoir storage capacity is required to maintain a yield with a given probability of failure?". It is an important issue in terms of construction and cost. HYDROMED offers a solution based on the modified Gould probability matrix method. This method has the advantage of sampling all years data without reference to the sequence and is therefore particularly suitable for catchments with patchy data. In the HYDROMED model, the probability of failure is calculated on a monthly basis. The model has been applied to the El-Gouazine catchment in Tunisia using a long rainfall record from Kairouan together with the estimated Hortonian runoff, class A pan evaporation data and estimated abstraction data. Generally, the probability of failure differed from winter to summer. Generally, the probability of failure approaches zero when the reservoir capacity is 500,000 m3. The 25% probability of failure (75% success) is achieved with a reservoir capacity of 58,000 m3 in June and 95,000 m3 in January. The probability of failure for a 240,000 m3 capacity reservoir (closer to storage capacity of El-Gouazine 233,000 m3), is approximately 5% in November, December and January, 3% in March, and 1.1% in May and June. Consequently there is no high risk of El-Gouazine being unable to meet its requirements at a capacity of 233,000 m3. Subsequently the benefit, in terms of probability of failure, by increasing the reservoir volume of El-Gouazine to greater than the 250,000 m3 is not high. This is important for the design engineers and the funding organizations. However, the analysis is based on the existing water abstraction policy, absence of siltation rate data and on the assumption that the present climate will prevail during the lifetime of the reservoir. Should these conditions change, a new analysis should be carried out. Keywords: HYDROMED, reservoir, storage capacity, probability of failure, Mediterranean
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Blanckenhorn, Wolf, und Claudia Mühlhäuser. „The quantitative genetics of sexual selection in the dung fly Sepsis cynipsea“. Behaviour 141, Nr. 3 (2004): 327–41. http://dx.doi.org/10.1163/156853904322981888.
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AbstractIn the common dung or black scavenger fly Sepsis cynipsea (Diptera: Sepsidae) several morphological and behavioural male and female traits interact during mating. Previous studies show that males attempt to mount females without courtship, females use vigorous shaking behaviour in response to male mounting, the duration of shaking is an indicator of both direct and indirect female choice and sexual conflict, and larger males enjoy a mating advantage. We conducted a quantitative genetic paternal half sib study to investigate the genetic underpinnings of these traits, notably body size (the preferred trait) and the associated female preference, and to assess the relative importance of various models generally proposed to account for the evolution of sexually selected traits. Several morphological traits and female shaking duration were heritable, thus meeting a key requirement of all sexual selection models. In contrast, two traits indicative of male persistence in mating were not. Male longevity was also heritable and negatively correlated with his mating effort, suggesting a mating cost. However, the crucial genetic correlation between male body size and female shaking duration, predicted to be negative by both 'good genes' and Fisherian models and positive by the sexual conflict (or chase-away) model, was zero. This could be because of low power, or because of constraints imposed by the genetic correlation structure. Based on our rsults we conclude that discriminating sexual selection models by sole means of quantitative genetics is difficult, if not impossible.
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Martinková, Zdenka, Alois Honěk, Stano Pekár und Leona Leišova-Svobodová. „Geographic differentiation of adaptive phenological traits of barnyardgrass (Echinochloa crus-galli) populations“. Weed Science 69, Nr. 3 (15.02.2021): 353–61. http://dx.doi.org/10.1017/wsc.2021.11.
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AbstractIn central Europe, barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.], has commonly been found in humid lowland areas. As a result of the introduction of new crops and farming practices, in the northwest Carpathians, E. crus-galli has spread from lowland (<200 m altitude) to highland (>400 m altitude) areas. We collected seed samples from local populations lying at a distance of approximately 5 km from each other and lined up along transects following the flows of two rivers. The rivers first flow through the valleys separated by mountain ridges and eventually flow into a common lowland. After ripening, the seeds of all populations were germinated at 25 C under long-day conditions. Only the seeds of some lowland populations germinated up to 75%. The frequency of germinated seeds decreased as the altitude where the population was collected increased, and above 200 m above sea level, germination was mostly zero. We then studied the phenological and morphological differentiation of plants from the original (lowland) and recently occupied (highland) areas. Seeds of the lowest and the highest localities lying on the transect of each river were sown in a common garden experiment. In plants from the highland localities, heading and seed dispersal were earlier, while tiller height and tiller mass were lower than in plants from the lowland localities. Seed mass produced per tiller in the lowland and highland plants was similar, and as a result, highland plants allocated a larger proportion of body mass to seed production than did lowland plants. Echinochloa crus-galli populations from highland localities thus produce their progeny earlier and at a lower energy cost than populations from lowland localities. The plasticity of phenological characters likely facilitated adaptation during E. crus-galli spread from lowlands to highlands. Similar adaptations in plant phenology may contribute to the spread of E. crus-galli in other geographic areas.
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Danyk, Yu, O. Zborovska und N. Rodina. „Models and mechanisms of formation of posttraumatic stress disorders in hybrid war (conflicts) and their features“. Fundamental and applied researches in practice of leading scientific schools 31, Nr. 1 (28.02.2019): 44–53. http://dx.doi.org/10.33531/farplss.2019.1.09.
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In study was conducted analysis and systematic studies of war syndromes, the end of the 20th and early 21st centuries ("Vietnamese syndrome", "Persian Gulf syndrome", "Afghan syndrome," etc.). For the first time are presented the systemic symptoms of the hybrid war syndrome (hybrid conflict) on the basis of the analysis, the application of the method of historical analogies, comparison, systematization and interpretation of facts, abstraction and concretization.
For the first time, the presence of the following stages of its development in the process of formation of PTSD has been proven: the "pre-PTSD", the latent phase "soft PTSD" (which already takes place, but obviously does not manifest itself and can be detected only by instrumental (hardware) methods) and "formed PTSD" (as a rule, one that is completely formed, clearly manifested, stable, multisymptomatic, and deployed, which, in the absence of its timely detection and treatment, is more likely to be transformed into a post-traumatic personality disorder).
The issues of informational and cognitive trauma of personnel and population were considered on the basis of the analysis of the striking factors of information and cognitive weapons and the peculiarities of their salvage in the Hybrid War.
We identified and described in our model of formation of PTSD in the context of the hybrid war "zero" - "entry into military service" stage and the three main stages of the emergence and formation of the PTSD.
The first stage is "preparatory": Phases: 1) General training; 2) training in the units in the conditions most close to combat (primary "Vaccinations" from PTSD); 3) Combat coordination of units (secondary "Vaccinations" from PTSD). The second stage of "stay in the crisis zone": 1) phase - sending to the area of military action; 2) participation in military action; 3) retirement. The third stage "Return from the combat zone". Particular emphasis should be put on other models of PTSD formation in specialists who do not take direct participation in battles, but are in a state of high nervous-psychological stress.
Stress is due the influence of responsibility for the effectiveness of use in the area of military action or in the enemy territory of high-cost, high-tech means on which the effectiveness of action depends in general, and the lives of combatants (for example, LAC crews and, in particular, UAV operators (2nd model) and military pilots flying aircraft (airplanes / helicopters) (3rd moth model). The first and second stages of the formation of PTSD in them are similar to the above-mentioned one model of the formation of PTSD. Differences with the 1st model and between the second and third models develop in the third stage.
It has also been established that PTSD may occur immediately after a traumatic event, or can lead to a negative long-term symptom and show symptoms that are sufficient for the diagnosis of PTSD (or the conditions / illness associated with it), even over the years.
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O'Hara, Jamie, Ceri Hirst, Stephan Rauchensteiner und Tom Burke. „Bay 81-8973 in the Real World: Clinical Effectiveness and Safety in Patients with Hemophilia Α across the US and Europe“. Blood 132, Supplement 1 (29.11.2018): 5044. http://dx.doi.org/10.1182/blood-2018-99-116814.
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Abstract Background: BAY 81-8973 (Kovaltry®, Bayer) is an unmodified full-length recombinant FVIII launched in 2016 in Europe and the US for the prophylaxis and treatment of bleeds in patients with hemophilia A. BAY 81-8973 has been extensively studied in clinical trials, which have demonstrated consistent efficacy and safety in both children and adults in the LEOPOLD trials, and since launch, 6750 patient-years of experience have been accumulated. Pharmacokinetic analyses have demonstrated an increased half-life for BAY 81-8973 compared with standard factor VIII products (rFVIII-FS and rFVIII [rAHF-PFM]). Real world evidence demonstrating the effectiveness and safety of BAY 81-8973 across age groups is being collected, though aggregated international data have yet to be published. The primary objective of this analysis was to describe the effectiveness of BAY 81-8973 in the real world setting in children and adults from Europe and the US, as captured in the Cost of Haemophilia: a Socioeconomic Survey (CHESS) study. Methods: The CHESS 2018 program investigated the economic and psychological burden of moderate and severe hemophilia (FVIII < 5%) in Europe and the USA. The pediatric cohort (CHESS Pediatric) included 1050 males aged 1-17 years, with moderate or severe hemophilia, while CHESS US included 568 adults with severe hemophilia aged > 18 years. Clinical and patient reported data were obtained via medical chart abstraction and cross-sectional surveys sent to both physicians and patients. Data were collected between December 2017 and April 2018, and captured 12 months of clinical retrospective data. The current study is a descriptive analysis of patients treated with BAY 81-8973 from the CHESS pediatric and adult cohorts. Results: At the data cut off (May 2018), 49 patients were being treated with BAY 81-8973. The majority of pediatric patients were aged 6-11 years (51.7%, n=15), while 17.2% (n=5) were aged 0-5 years and 31% (n=9) were aged 12-17 years. In the adult US cohort, most (60%, n=12) were aged 18-35 years, 35% (n=7) were aged 36-59 years, and 5% (n=1) were aged > 60 years. The vast majority of patients across cohorts had severe disease (93.1% of children and 100% of adults); however, 89.7% (26/29) of children and 80% (16/20) of adults had no target joints. In this population, 75.9% (22/29) of children and 55.0% (11/20) of adults were receiving regular prophylaxis with BAY 81-8973. Children and adults on prophylaxis both had a mean (± SD) of 2 (± 1) infusions/week, with median (Q1; Q3) weekly doses of 84 (67; 110) and 62 (29; 144) IU/kg, respectively. Overall, 20.7% (6/29) of children and 35% (7/20) of adults treated with BAY 81-8973 had zero bleeds and mean annualized bleed rate (ABR) was 2.66 (± 2.06) in children and 1.45 (± 1) in adults; 68.9% (20/29) of children and 95.0% (19/20) of adults had experienced ≤ 3 bleeds in the previous year. There were no reports of inhibitor development in either the pediatric or adult cohorts while on BAY 81-8973. Conclusions: These observations suggest that BAY 81-8973 is an effective and well-tolerated treatment for adults and children with moderate and severe hemophilia A, with ABR < 3 in children and < 2 in adults and with many patients free from bleeds despite only 67% of patients studied receiving regular prophylaxis. These data confirm the observations from the LEOPOLD trials, suggest BAY 81-8973 provides good protection from bleeding across a range of patient types in routine clinical practice and illustrate how the established pharmacokinetic profile of BAY 81-8973 translates to clinical benefits for patients with hemophilia A. Study supported by Bayer Disclosures Hirst: Bayer: Employment. Rauchensteiner:Bayer: Employment.
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BREITNER, JOACHIM, RICHARD A. EISENBERG, SIMON PEYTON JONES und STEPHANIE WEIRICH. „Safe zero-cost coercions for Haskell“. Journal of Functional Programming 26 (2016). http://dx.doi.org/10.1017/s0956796816000150.
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AbstractGenerative type abstractions – present in Haskell, OCaml, and other languages – are useful concepts to help prevent programmer errors. They serve to create new types that are distinct at compile time but share a run-time representation with some base type. We present a new mechanism that allows for zero-cost conversions between generative type abstractions and their representations, even when such types are deeply nested. We prove type safety in the presence of these conversions and have implemented our work in GHC.
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Vilela, Juliana, und Richard Hill. „Hierarchical planning in a supervisory control context with compositional abstraction“. Discrete Event Dynamic Systems, 14.09.2021. http://dx.doi.org/10.1007/s10626-021-00349-x.
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AbstractHierarchy is a tool that has been applied to improve the scalability of solving planning problems modeled using Supervisory Control Theory. In the work of Hill and Lafortune (2016), the notion of cost equivalence was employed to generate an abstraction of the supervisor that, with additional conditions, guarantees that an optimal plan generated on the abstraction is also optimal when applied to the full supervisor. Their work is able to improve their abstraction by artificially giving transitions zero cost based on the sequentially-dependent ordering of events. Here, we relax the requirement on a specific ordering of the dependent events, while maintaining the optimal relationship between upper and lower levels of the hierarchy. This present paper also extends the authors’ work (Vilela and Hill 2020) where we developed a new notion of equivalence based on cost equivalence and weak bisimulation that we term priced-observation equivalence. This equivalence allows the supervisor abstraction to be generated compositionally. This helps to avoid the explosion of the state space that arises from having to first synthesize the full supervisor before the abstraction can be applied. Here, we also show that models with artificial zero-cost transitions can be created compositionally employing the new relaxed sequential dependence definition. An example cooperative robot control application is used to demonstrate the improvements achieved by the compositional approach to abstraction proposed by this paper.
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Køien, Geir M. „Zero-Trust Principles for Legacy Components“. Wireless Personal Communications, 03.09.2021. http://dx.doi.org/10.1007/s11277-021-09055-1.
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AbstractIn this paper we briefly outline as set of rules for integration of legacy devices into a modern industrial control system. These rules are fairly simple, and are mostly derived from “Zero Trust” principles. These rules aim to be pragmatic, and cost-effectiveness trumps completeness.
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Wang, Hong, Zhuoyu Ji, Liwei Shang, Yingping Chen, Congyan Lu, Dongmei Li, Yingquan Peng und Ming Liu. „Low-cost 13.56MHz Rectifier Based on Organic Diode“. MRS Proceedings 1402 (2012). http://dx.doi.org/10.1557/opl.2012.145.
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ABSTRACTIn this paper, low-cost rectifier based on an organic diode for use in organic radio frequency identification (RFID) tags is proposed. Pentacene is the electroactive layer, with 7,7,8,8-tetracyanoquinodimethane (TCNQ) modified low-cost copper (Cu) and aluminum (Al) as the Ohmic and Schottky contacts, respectively. Hole injection barrier between Cu and pentacene can be decreased by forming the self-assembled layers of Cu-TCNQ. The diode shows a high rectification ratio of approximately 2×106 at 5V and the organic diode based rectifier circuit generated a dc output voltage of approximately 2V at 13.56MHz, using an input ac signal with zero-to-peak voltage amplitude of 5 V. The results indicate that chemical modification of the low-cost electrodes could be an efficient way toward low-cost high performance organic electronics devices.
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Accardi, Luigi, und Massimo Regoli. „On a class of strongly asymmetric PKA algorithms“. Journal of Mathematical Cryptology 9, Nr. 3 (01.01.2015). http://dx.doi.org/10.1515/jmc-2015-0019.
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AbstractIn the papers [New features for public key exchange algorithms, in: 18-th International ICWG Meeting (Krakow 2011)], [Strongly asymmetric PKD cryptographic algorithms: An implementation using the matrix model, in: Proceedings ISEC Conference (Shizuoka 2011)] a new scheme to produce public key agreement (PKA) algorithms was proposed and some examples based on polynomials (toy models) were discussed. In the present paper we introduce a non-commutative realization of the above mentioned scheme and prove that non-commutativity can be an essential ingredient of security in the sense that, in the class of algorithms constructed, under some commutativity assumptions on the matrices involved, we can find a breaking strategy, but dropping these assumptions we can not, even if we assume, as we do in all the attacks discussed in the present paper, that discrete logarithms have zero cost.
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Dawodu, Folasegun A., Benjamin M. Akpan und Kovo G. Akpomie. „Sequestered capture and desorption of hexavalent chromium from solution and textile wastewater onto low cost Heinsia crinita seed coat biomass“. Applied Water Science 10, Nr. 1 (19.12.2019). http://dx.doi.org/10.1007/s13201-019-1114-6.
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AbstractDue to the high cost associated with the treatment of effluents containing heavy metals in the environment, the continuous untreated release of effluent containing chromium from textile industries has resulted in several adverse effects to plants, ecological systems and humans. This research therefore focused on the use of a low cost, biodegradable Heinsia crinita seed coat (HCSC) material for the biosorption of chromium(VI) from aqueous and textile contaminated effluent. The biosorbent was characterized for specific surface area, surface morphology, pH point of zero charge and surface functional groups. Operational variables influences such as biosorbent dose, pH, temperature, initial Cr(VI) ion concentration and contact time on biosorption process was tested. The optimum biosorption parameter was obtained at pH 2.0, adsorbent dosage 0.25 g and contact time of 30 min. From sorption analysis, the pseudo-second-order model best described the attenuation kinetics. Concerning biosorption equilibrium, the results suggested that the adsorption isotherm obeyed the Freundlich model. Langmuir maximum monolayer biosorption capacity of 231.7 mg/g was higher than most biosorbents for Cr(VI) ion. The thermodynamic data showed a physical, spontaneous and endothermic biosorption process. HCSC showed high percentage desorption > 90% using 0.1 M HNO3 and was efficient after three cycles of regeneration studies. The results showed HCSC biomass as a suitable candidate for abstraction of Cr(VI) ion from contaminated solution and textile effluent.
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Berger, Mathias, David Radu, Ghislain Detienne, Thierry Deschuyteneer, Aurore Richel und Damien Ernst. „Remote Renewable Hubs for Carbon-Neutral Synthetic Fuel Production“. Frontiers in Energy Research 9 (10.06.2021). http://dx.doi.org/10.3389/fenrg.2021.671279.
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This paper studies the economics of carbon-neutral synthetic fuel production from renewable electricity in remote areas where high-quality renewable resources are abundant. To this end, a graph-based optimisation modelling framework directly applicable to the strategic planning of remote renewable energy supply chains is proposed. More precisely, a hypergraph abstraction of planning problems is introduced, wherein nodes can be viewed as optimisation subproblems with their own parameters, variables, constraints and local objective. Nodes typically represent a subsystem such as a technology, a plant or a process. Hyperedges, on the other hand, express the connectivity between subsystems. The framework is leveraged to study the economics of carbon-neutral synthetic methane production from solar and wind energy in North Africa and its delivery to Northwestern European markets. The full supply chain is modelled in an integrated fashion, which makes it possible to accurately capture the interaction between various technologies on an hourly time scale. Results suggest that the cost of synthetic methane production and delivery would be slightly under 150 €/MWh (higher heating value) by 2030 for a system supplying 10 TWh annually and relying on a combination of solar photovoltaic and wind power plants, assuming a uniform weighted average cost of capital of 7%. A comprehensive sensitivity analysis is also carried out in order to assess the impact of various techno-economic parameters and assumptions on synthetic methane cost, including the availability of wind power plants, the investment costs of electrolysis, methanation and direct air capture plants, their operational flexibility, the energy consumption of direct air capture plants, and financing costs. The most expensive configuration (around 200 €/MWh) relies on solar photovoltaic power plants alone, while the cheapest configuration (around 88 €/MWh) makes use of a combination of solar PV and wind power plants and is obtained when financing costs are set to zero.
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Islam, Mohammad Tariqul, Md Moniruzzaman, Touhidul Alam, Md Samsuzzaman, Qutaiba A. Razouqi und Ali F. Almutairi. „Realization of frequency hopping characteristics of an epsilon negative metamaterial with high effective medium ratio for multiband microwave applications“. Scientific Reports 11, Nr. 1 (19.08.2021). http://dx.doi.org/10.1038/s41598-021-96228-4.
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AbstractIn this paper, a meander-lines-based epsilon negative (ENG) metamaterial (MTM) with a high effective medium ratio (EMR) and near-zero refractive index (NZI) is designed and investigated for multiband microwave applications. The metamaterial unit cell is a modification of the conventional square split-ring resonator in which the meander line concept is utilized. The meander line helps to increase the electrical length of the rings and provides strong multiple resonances within a small dimension. The unit cell of proposed MTM is initiated on a low-cost FR4 substrate of 1.5 mm thick and electrical dimension of 0.06λ × 0.06λ, where wavelength, λ is calculated at the lowest resonance frequency (2.48 GHz). The MTM provides four major resonances of transmission coefficient (S21) at 2.48, 4.28, 9.36, and 13.7 GHz covering S, C, X, and Ku bands. It shows negative permittivity, near-zero permeability, and near-zero refractive index in the vicinity of these resonances. The equivalent circuit is designed and modeled in Advanced Design System (ADS) software. The simulated S21 of the MTM unit cell is compared with the measured one and both show close similarity. The array performance of the MTM is also evaluated by using 2 × 2, 4 × 4, and 8 × 8 arrays that show close resemblance with the unit cell. The MTM offers a high effective medium ratio (EMR) of 15.1, indicating the design's compactness. The frequency hopping characteristics of the proposed MTM is investigated by open and short-circuited the three outer rings split gaps by using three switches. Eight different combinations of the switching states provide eight different sets of multiband resonances within 2–18 GHz; those give the flexibility of using the proposed MTM operating in various frequency bands. For its small dimension, NZI, high EMR, and frequency hopping characteristics through switching, this metamaterial can be utilized for multiband microwave applications, especially to enhance the gain of multiband antennas.
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Islam, M. Tarikul, Md Samsuzzaman, Salehin Kibria, Norbahiah Misran und Mohammad Tariqul Islam. „Metasurface Loaded High Gain Antenna based Microwave Imaging using Iteratively Corrected Delay Multiply and Sum Algorithm“. Scientific Reports 9, Nr. 1 (21.11.2019). http://dx.doi.org/10.1038/s41598-019-53857-0.
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AbstractIn this paper, the design consideration is investigated for a cylindrical system with low-cost and low-loss dielectric materials for the detection of breast tumor using iteratively corrected delay multiply and sum (IC- DMAS) algorithm. Anomaly in breast tissue is one of the most crucial health issues for women all over the world today. Emergency medical imaging diagnosis can be harmlessly managed by microwave-based analysis technology. Microwave Imaging (MI) has been proved to be a reliable health monitoring approach that can play a fundamental role in diagnosing anomaly in breast tissue. An array of 16 high gain microstrip antennas loaded by Index Near-Zero (INZ) metasurfaces (MS), having the impedance bandwidth of 8.5 GHz (2.70–11.20 GHz) are used as transceivers for the system. The MS is used to increase the electrical length of the signal that results in the gain enhancements. The antennas are mounted in a cylindrical arrangement on a mechanical rotating table along with a phantom mounting podium. A non-reflective positive control switching matrix is used for transmitting and receiving microwave signals. A set of lab-made realistic heterogeneous breast phantoms containing skin, fat, glandular, and tumor tissue dielectric properties in individual layers are used to verify the performance of the proposed technique. The control of the mechanical unit, data collection, and post-processing is conducted via MATLAB. The system can detect multiple tumor objects. The imaging results and numerical Signal to Mean Ratio (SMR) values of the experiment validate the system efficiency and performance that can be a viable solution for tumor detections.
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Beshah, Dawit Alemu, Girum Ayalneh Tiruye und Yedilfana Setarge Mekonnen. „Characterization and recycling of textile sludge for energy-efficient brick production in Ethiopia“. Environmental Science and Pollution Research, 02.01.2021. http://dx.doi.org/10.1007/s11356-020-11878-7.
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AbstractIn recent years, an enormous amount of sludge is generated every day from zero liquid discharge treatment plant due to rapid expansion of industrial parks in Ethiopia. About 30,000 tons of partially dried sludge discharged to the environmental without proper waste management from all industrial parks. Thus, posing serious environmental problems. One of the most plausible means to recycle the excess sludge resource is converting it into energy-efficient brick by combining with clay. Bricks were prepared by incorporating textile sludge at different proportions (10–40%) and temperature (600, 900 and 1200 °C). Clay and sludge samples were collected from the Addis Ababa brick factory PLC and Hawassa Industrial Park. Results revealed that 10 and 20% sludge bricks satisfied criteria of class “A” bricks as per Ethiopia standards, with the compressive strength of 30.43 and 29.10 Mpa, respectively, at 1200 °C. About 26 and 50% of energy were saved during firing of 10 and 20% sludge-containing bricks, respectively, compared with pristine clay bricks. Moreover, too low concentrations of selected heavy metals found in the brick leachate, showing the sludge, were effectively stabilized in the burnt clay bricks. Thus, based on the results, we suggest the rapid utilization of huge amount of partially dried sludge resources for low-cost and efficient large-scale brick production. This will mutually benefit both the industrial parks and brick production industries. In addition, this will create thousands of jobs to the local people. Above all, the solid waste will be managed properly at textile industrial parks.