Strict Limits Research Articles

Effects of steam sterilization on reduction of fungal colony forming units, cannabinoids and terpene levels in medical cannabis inflorescences

Medical cannabis (MC) production is a rapidly expanding industry. Over the past ten years, many additional phytocannabinoids have been discovered and used for different purposes. MC was reported beneficial for the treatment of a variety of clinical conditions such as analgesia, multiple sclerosis, spinal cord injuries, Tourette's syndrome, epilepsy, glaucoma, Parkinson disease and more. Yet, there is still a major lack of research and knowledge related to MC plant diseases, both at the pre- and postharvest stages. Many of the fungi that infect MC, such as Aspergillus and Penicillium spp., are capable of producing mycotoxins that are carcinogenic, or otherwise harmful when consumed, and especially by those patients who suffer from a weakened immune system, causing invasive contamination in humans. Therefore, there are strict limits regarding the permitted levels of fungal colony forming units (CFU) in commercial MC inflorescences. Furthermore, the strict regulation on pesticide appliance application in MC cultivation exacerbates the problem. In order to meet the permitted CFU limit levels, there is a need for pesticide-free postharvest treatments relying on natural non-chemical methods. Thus, a decontamination approach is required that will not damage or significantly alter the chemical composition of the plant product. In this research, a new method for sterilization of MC inflorescences for reduction of fungal contaminantstes was assessed, without affecting the composition of plant secondary metabolites. Inflorescences were exposed to short pulses of steam (10, 15 and 20 s exposure) and CFU levels and plant chemical compositions, pre- and post-treatment, were evaluated. Steam treatments were very effective in reducing fungal colonization to below detection limits. The effect of these treatments on terpene profiles was minor, resulting mainly in the detection of certain terpenes that were not present in the untreated control. Steaming decreased cannabinoid concentrations as the treatment prolonged, although insignificantly. These results indicate that the steam sterilization method at the tested exposure periods was very effective in reducing CFU levels while preserving the initial molecular biochemical composition of the treated inflorescences.

A Novel Integer Linear Programming Formulation for Job-Shop Scheduling Problems

Job-shop scheduling is an important but difficult problem arising in low-volume high-variety manufacturing. It is usually solved at the beginning of each shift with strict computational time requirements. To obtain near-optimal solutions with quantifiable quality within strict time limits, a direction is to formulate them in an Integer Linear Programming (ILP) form so as to take advantages of widely available ILP methods such as Branch-and-Cut (B&C). Nevertheless, computational requirements for ILP methods on existing ILP formulations are high. In this letter, a novel ILP formulation for minimizing total weighted tardiness is presented. The new formulation has much fewer decision variables and constraints, and is proven to be tighter as compared to our previous formulation. For fast resolution of large problems, our recent decomposition-and-coordination method “Surrogate Absolute-Value Lagrangian Relaxation” (SAVLR) is enhanced by using a 3-segment piecewise linear penalty function, which more accurately approximates a quadratic penalty function as compared to an absolute-value function. Testing results demonstrate that our new formulation drastically reduces the computational requirements of B&C as compared to our previous formulation. For large problems where B&C has difficulties, near-optimal solutions are efficiently obtained by using the enhanced SAVLR under the new formulation.

Does a Starting Positive End-Expiratory Pressure of 8 cm H2O Decrease the Probability of a Ventilator-Associated Event?

Background: Mechanical ventilation is commonly seen in critical ill patients. The vulnerability of these patients is high, and a wide range of associated conditions can stem from this intervention. To objectively identify nosocomial respiratory conditions and provide conformed surveillance definitions of these events, the Centers for Disease Control and Prevention (CDC) established the ventilator-associated event (VAE) criteria. They denote 3 categories of increasing progression in mechanically ventilated patients from a ventilator-associated condition (VAC) to an infection-related ventilator-associated complication (IVAC) and finally to a possible ventilator-associated pneumonia (PVAP). Manipulation of ventilator settings, such as starting on higher values to not trigger VAC criteria, has been criticized by some experts as not only ‘gaming the system,’ but potentially harming patients. In October 2018, our institution began a baseline of 8 cm H2O as the starting positive end-expiratory pressure (PEEP) protocol for mechanical ventilation but exempting neurosurgical patients. We sought to determine whether an 8 PEEP protocol is an effective strategy for reducing VAEs in our institution. Methods: We retrospectively examined patient data at our institution from January 2014 through February 2020. VAEs were separated by VAC only and IVAC positive (+), which are a combination of IVACs and PVAPs. Using the days between VAEs, a daily event probability can be calculated based on the geometric distribution. Furthermore, as VAEs occur, the likelihood of the event can be assessed as expected or unexpected using a strict probability limit of 0.99865 to reduce type 1 errors. Results: In total, 307 patients were identified in our hospital’s VAE surveillance. Of those, 180 met CDC-defined VAC-only criteria, and 127 patients met IVAC+ definitions. After implementation of an 8-PEEP protocol, the daily event probability for VACs decreased from 0.083 to 0.047. The last event occurred 162 days after the previous VAC, which was unexpected, because the probability of occurrence extended beyond the probability limit. With regard to IVAC+ events, the daily event probability decreased from 0.057 to 0.039 without significant reduction in the IVAC+ rate. Conclusions: Although a change in the VAC-only rate occurred, signified by a longer time between events, it took more than a year to achieve in our institution. Additionally, we did not see a reduction in the IVAC+ rate. These findings suggest that an 8-PEEP protocol may be able to reduce VAEs due to noninfectious etiologies, such as congestive heart failure and atelectasis.Funding: NoDisclosure: None

Multiobjective optimization and parameters study of hybrid offshore wind and pumped hydrostorage power system: Modeling and case study

Offshore wind energy has been widely exploited as a promising renewable energy source in China in recent years. This renewable source's high curtailment rate due to strict wind energy penetration limits, however, remains a challenge of concern. Also, the difference between peak and valley loads of electric power systems continues to increase with economic and societal development. To address these issues, this study proposes a hybrid system composed of a high-capacity offshore wind farm coupled with a pumped hydrostorage (PHS) power system to absorb rejected wind power. The hydraulic energy stored by PHS system is expected to provide guaranteed energy during peak load demands on the main power grid. This study presents a multiobjective technoeconomic assessment model based on the principle of dynamic economy for optimizing the size of the PHS system. The conclusions can be summarized as follows: (1) the seasonal characteristics affect the utilization of wind energy; (2) PHS operating strategies have an influence on the PHS configuration, energy utilization, and economic benefit; (3) reducing the wind curtailment is the key to improve the system performance and economic feasibility; (4) the drop in water level has a negative effect on economic benefit and (5) provides clear guidance to set external financial parameters for a hybrid power station. The results show that a size-optimizing study is important in determining the system's economic feasibility and predicted performance.

A Prognostic Classifier Based on Early Platelet Drop in Lower-Risk MDS. a Study from the European Leukemianet Lower-Risk MDS (EUMDS) Registry

▪Context: Prognosis of lower-risk (IPSS low/int-1) MDS is heterogeneous. Current prognostic systems rely on steady-state values for cytopenias. Capturing the dynamics of these parameters could yield additional prognostic information. We analyzed the prognostic relevance of relative drop (%) in neutrophil (ANC) and platelet (PLT) counts during the first six months follow-up of lower-risk MDS patients included in the EUMDS registry.Methods: TheEUMDS registry includes prospectively patients (pts) within the first 100 days of diagnosis of lower-risk (IPSS low/intermediate-1) MDS. We performed a landmark analysis of overall survival (OS) in pts with a visit at 6±1 months from inclusion to assess the prognostic relevance of a relative drop in ANC and PLT over the first 6 months follow-up. Relative ANC and PLT drops were defined as: (ANC at landmark - ANC at inclusion) / ANC at inclusion, respectively (resp) for PLT.Results: As of Sept 2016,1,800 patients with ≥5 months follow-up were included in the registry. 807 patients with a second visit at 6±1 months from inclusion were analyzed. Reasons for exclusion from this cohort were: no visit within the strict limits of 6±1 month (n=904), no PLT count at baseline (n=40) or 6-month visit (n=20), and no follow-up beyond 6-month visit (n=19). Median age was 73 yr, IPSS-R was very-low, low, intermediate or higher in 26%, 43% 24% and 7% of pts, resp. Median time to landmark was 183 days. Median follow-up from landmark was 37.8 months. Median relative drop in ANC and PLT was 5.2% and 4.6%, resp. At landmark, 41 patients (5%) received treatments affecting ANC or PLT (hypomethylating agents, lenalidomide or hydroxycarbamide). Excluding them did not affect results. Relative ANC and PLT drop were dichotomized at the 25% threshold. Sensitivity analyses with different cutoffs did not affect our final conclusions. Multivariate logistic regressions identified RBC- transfusion dependency (TD) at inclusion (OR=1.7, p=0.02) as the main predictor of 6-month relative PLT drop > 25%, while higher baseline ANC as a continuous value was associated with 6-month ANC drop >25% (10-4). The latter suggests that the dynamic range of ANC does not allow uniform assessment of ANC drop in all MDS patients.In univariate analysis, a relative drop in PLT >25% (HR=2.3, p<10-4) was associated with shorter OS after the 6-month landmark (median 29.2 months vs 57.1 in pts with PLT drop ≤25%, p<10-4), and increased cumulative incidence of progression (CIP: standardized HR: 2.5, p<10-4), while relative ANC drop >25% only predicted higher CIP (standardized HR: 1.5, p=0.03), without significant impact on OS (p=0.12). The adverse prognosis of relative PLT drop was observed regardless of baseline IPSS-R or absolute PLT count at inclusion or landmark.We subsequently divided our cohort in a training (n=403) and a validation (n=404) set to derive a prognostic model applicable at the 6-month landmark. Variables included age, gender and IPSS-R at inclusion, RBC-TD, steady-state PLT and ANC values at landmark, and relative PLT and ANC drop (with the 25% cutoff). Cox models with variable selection by penalized regression identified older age (p<10-4), RBC-TD at landmark (p<10-4) and relative PLT drop >25% (p=0.005) as independent prognostic factors. We built a simple age-independent 6-month EUMDS classifier based on RBC-TD at landmark and relative PLT drop >25%, where patients with none (53%), either (31%) or both criteria (16%) had median OS from landmark of 71, 42 and 19 months, resp, p<10-4). The classifier performed equally well in the validation set (p<10-4). A sensitivity analysis relaxing the timing of landmark drop was carried on an ‘extended cohort’ of 1610 (89%) registry pts with a second visit within ten months of inclusion. This analysis confirmed the adverse prognostic value of a relative PLT drop >25% within 10 months of diagnosis of lower-risk MDS and the broad applicability of the EUMDS classifier, regardless of baseline IPSS-R risk (Figure).Conclusion: Early drop in platelets during the first 6 months of follow-up holds prognostic significance in lower-risk MDS. A 6-month classifier based on RBC-TD at 6 month and a relative platelet drop greater than 25% can inform prognosis of lower-risk MDS independently from IPSS-R. [Display omitted] DisclosuresItzykson:Novartis: Research Funding; Janssen: Research Funding. Sanz:Gamida Cell: Research Funding. Germing:Janssen: Honoraria; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Almeida:Novartis: Consultancy; Celgene: Consultancy; Bristol Meyer Squibb: Honoraria; Alexion: Honoraria; Servier: Consultancy. Fenaux:Astex: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Astex: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding.

Preliminary demonstration on JET of an ITER neutron environment-compatible quadrupole mass-spectrometer✰

Strict limits recently imposed on neutron exposure to electronics for critical diagnostic systems on ITER, the fusion reactor demonstration facility under construction in the south of France, has led to the development of a quadrupole mass spectrometer with an exceptionally long cable. An 80 m cable exceeds the last state-of-the art limit of 15 m, imposed by the normally required proximity of the RF supply to the analyzer, and will allow locating the electronics in a neutron safe environment. This breakthrough, a joint development of ORNL with Hiden Analytical Ltd., was enabled by the use of an intermediate, RF-matching unit, free of silicon-based electronics, and using only vacuum tubes and an air-core transformer, rendering it resilient both to ionizing radiation and to fringing magnetic fields. After successful testing of the prototype unit, both at ORNL and Hiden's laboratories, the unit was installed on the JET tokamak, as part of a multi-sensor, divertor effluent gas analysis system, similar to one also under design for ITER. As such, the prototype will be tested both before and during the next nuclear (D-T) operation of JET, planned for mid-2021. In this paper, the prototype development, laboratory testing and first results from non-nuclear plasma pulse testing on JET are presented. The latter include not only successful detection of fusion fuel cycle and impurity species, but also improved resolution and stability over the state-of-the-art, 15m-cable units on the same analysis station.

Application of plant-derived bioactive compounds as seed treatments to manage the rice pathogen Fusarium fujikuroi

Plant essential oils (EO) possess antifungal properties due to the presence of terpenoids and phenolics capable of damaging microbial cell membranes. The compounds present in EO could represent a valid alternative to synthetic fungicides in rice crop protection, especially in Europe, where the available plant protection products are increasingly scarce, particularly for managing seed-borne fungal pathogens like Fusarium fujikuroi Nirenberg, the causal agent of bakanae disease. Bakanae is a major concern in Europe for seed producers, which often fail to comply with the strict regulatory limits on the presence of the pathogen in the field, resulting in the rejection of the seed crop from marketing and economic losses. The present work was aimed at studying 1) the in vitro effect of EO derived compounds against F. fujikuroi and 2) their efficacy in disease management under field conditions applied as seed treatments. Results confirmed the in vitro antifungal activity of tested compounds: specifically, thymol (0.025% vol/vol), terpinen-4-ol (0.1%), and eugenol (0.05%) showed strong antifungal activity against all the tested F. fujikuroi strains. Two-years, two-locations open field trials showed that seeds treated with thymol (20%) and eugenol (5%) significantly reduced bakanae incidence compared to untreated control, without any phytotoxicity effect on rice seed. The efficacy of these two compounds in managing the disease without affecting germination rates was comparable to the commercially available prochloraz and triticonazole formulation, considered as the positive control. Our results suggest that thymol and eugenol could be used as alternative fungicides in innovative formulations for seed dressing, with the advantage of being compliant with the European IPM framework and organic farming legislation.

Comparative economic analysis of technological priorities for low-carbon transformation of electric power industry in Russia and the EU

This paper explores the differences in technological priorities for decarbonization of the Russian and the European power sectors up to 2040 and investigates the main drivers of such differences. We used updated cost and performance data to conduct a comparative analysis of technologies based on levelized cost of electricity. Calculation of carbon avoided costs allowed us to found the pool of cost-efficient low-carbon technologies for the Russian power industry as well as the level of carbon prices needed to support their development. Also, we have explained the reasons which cause differences in decarbonization priorities in Russia and Europe. We have also investigated the impact of system requirements (and associated costs) in terms of capacity availability and its operating modes on the competitiveness of renewable energy sources and conventional power plants. Consideration of these requirements and costs improves the quality of power system planning and policy-making processes under the strict limits on greenhouse gas emissions. Based on performed analysis we suggest economically reasonable decarbonization strategy of the Russian power industry as well as the necessary level of carbon prices/taxes for various low- and non-carbon technologies to support their development.

Optimal hyper-scalable load balancing with a strict queue limit

Load balancing plays a critical role in efficiently dispatching jobs in parallel-server systems such as cloud networks and data centers. A fundamental challenge in the design of load balancing algorithms is to achieve an optimal trade-off between delay performance and implementation overhead (e.g. communication or memory usage). This trade-off has primarily been studied so far from the angle of the amount of overhead required to achieve asymptotically optimal performance, particularly vanishing delay in large-scale systems. In contrast, in the present paper, we focus on an arbitrarily sparse communication budget, possibly well below the minimum requirement for vanishing delay, referred to as the hyper-scalable operating region. Furthermore, jobs may only be admitted when a specific limit on the queue position of the job can be guaranteed.The centerpiece of our analysis is a universal upper bound for the achievable throughput of any dispatcher-driven algorithm for a given communication budget and queue limit. We also propose a specific hyper-scalable scheme which can operate at any given message rate and enforce any given queue limit, while allowing the server states to be captured via a closed product-form network, in which servers act as customers traversing various nodes. The product-form distribution is leveraged to prove that the bound is tight and that the proposed hyper-scalable scheme is throughput-optimal in a many-server regime given the communication and queue limit constraints. Extensive simulation experiments are conducted to illustrate the results.

Urban Infrastructure Resilience Assessment During Mega Sport Events Using a Multi-Criteria Approach

Critical infrastructures share the same space and mutual dependencies, and consequently contribute to city's overall resilience. However, each has different assessment methods and metrics, which prevents the integration of the performance results for different infrastructures into a single holistic evaluation index that can reflect the city's overall resilience and expected performance. To address this challenge, we propose the development of a multi-criteria-based integration approach that can allow the combination of different evaluation results from different assessment methods through partial factors. The proposed equation incorporates several factors, which can be divided into four groups: (1) method-efficiency factors, (2) infrastructure importance factors, (3) infrastructures' interdependency factors, and (4) strict limits that ensure that the infrastructures are suitable for hosting mega sports events. Using this approach, we hope to open the way for future research into suitable factors and facilitate resilience-based design in sustainable development and municipal planning.

Rotary regenerative shock absorbers for automotive suspensions

The increasingly strict limits on pollutant emissions are pushing the car industry towards the electrification of the powertrain and chassis. This scenario has driven the automotive field to the use of energy harvesters. Among these, regenerative shock absorbers are mechatronic devices that enable the energy recovery from road irregularities, thus yielding benefits in terms of fuel saving and ride quality. The state of the art proposes different technologies for regenerative dampers. In this context, rotary dampers represent an unexplored field from the scientific point of view. These devices feature a linkage and a gearbox to convert the suspension linear motion into rotation of an electric machine. This work proposes a novel system-level design methodology for rotary regenerative shock absorbers and explores their performance from an experimental perspective. The design is focused in yielding a compact solution able to fulfill a given damping specification. Hence, the integrated definition of electric machine, gearbox and linkage is addressed by the proposed method. To support the methodology, a case study is presented. A fully functional prototype is produced and successfully validated in terms of damping capability, total conversion efficiency and acoustic behavior. The obtained results demonstrate the validity of the proposed methodology and the advantageous features of rotary dampers with respect to other regenerative suspension solutions.

SN 2019yvq Does Not Conform to SN Ia Explosion Models

Abstract We present new photometric and spectroscopic observations of SN 2019yvq, a Type Ia supernova (SN Ia) exhibiting several peculiar properties including an excess of UV/optical flux within days of explosion, a high Si ii velocity, and a low peak luminosity. Photometry near the time of first light places new constraints on the rapid rise of the UV/optical flux excess. A near-infrared spectrum at +173 days after maximum light places strict limits on the presence of H or He emission, effectively excluding the presence of a nearby nondegenerate star at the time of explosion. New optical spectra, acquired at +128 and +150 days after maximum light, confirm the presence of [Ca ii] λ7300 and persistent Ca ii NIR triplet emission as SN 2019yvq transitions into the nebular phase. The lack of [O i] λ 6300 emission disfavors the violent merger of two C/O white dwarfs (WDs) but the merger of a C/O WD with a He WD cannot be excluded. We compare our findings with several models in the literature postulated to explain the early flux excess including double-detonation explosions, 56Ni mixing into the outer ejecta during ignition, and interaction with H- and He-deficient circumstellar material. Each model may be able to explain both the early flux excess and the nebular [Ca ii] emission, but none of the models can reconcile the high photospheric velocities with the low peak luminosity without introducing new discrepancies.

Evaluation of Liquefied Natural Gas as a Ship Fuel for Liner Shipping Using Evolutionary Game Theory

Strict limits on air emissions released by burning fuel of ships have recently been imposed in Emission Control Areas. Retrofitting ships to use Liquefied Natural Gas (LNG) as a ship fuel is one of the methods for liner companies to comply with global regulations. Since the LNG retrofitting investment is expensive, it is likely that liner companies need a more scientific methodology to evaluate the LNG for propulsion of ships. Liner companies are particularly interested in their profits determined by the pricing decision. Based on the evolutionary game theory, this paper develops a mathematical model for the pricing problem with the consideration of market competition, LNG investment, and price elasticity. We also consider several realistic factors, such as the demand sensitivity for LNG effort, to make the proposed methodology meet the realistic demands when more and more liner companies need a revolutionary transformation because of the stricter regulations. Numerical experiments, including a simulated-data case, are performed to validate the proposed methodology. Some managerial insights are concluded according to the computational experiments and sensitivity analysis.

BoP incidence on a 240 kW PEMFC system in a ship-like environment, employing a dedicated fuel cell stack model

New policies and strict emission limits in the transports sector result in a gradual switch towards alternative fuels and hydrogen is getting attention: fuel cell systems are considered ideal energy converters of the next future. As the interest is rising in Proton Exchange Membrane Fuel Cells (PEMFC), there is a need for experimental research and dedicated laboratories on systems designed with Balance of Plant. In this context, the HI-SEA Laboratory (240-kW PEMFC by Nuvera FC, a joint between the University of Genoa-Fincantieri) was born. In this paper, the tuning of the laboratory to simulate a ship-likely environment is addressed, looking at the main problematics and resolutions, related to the cathodic line and the cooling control. Some guidelines are defined to install a PEMFC system onboard a ship exploiting the existing infrastructure. Thanks to the experimental campaign, a stack voltage model previously validated is employed to evaluate the performance of the system.

Heavy Metals in Urban Street Dust: Health Risk Assessment (Lublin City, E Poland)

Various pollutants, including heavy metals, present in street dust can pose a threat to the health of city dwellers. So far, studies on levels of this threat have been carried out mainly in large cities, characterised by considerable road traffic and industrial activity. This paper assesses the levels of hazard index and cancer risk for Cd, Cr, Cu, Ni, Pb and Zn contained in street dust collected in 2013 and 2018 at 62 points located in different parts of a small/medium-sized city (Lublin, E Poland). Heavy metals contents were analysed by means of XRF spectrometry (in the fraction &lt;63 µm). Despite the fact that the concentrations of some elements (Zn, Cd and Cu) in street dust are 6–7 times higher than the geochemical background, this does not pose a risk of non-carcinogenic effects. The average hazard index (HI) for the individual elements reaches very low levels (&lt;0.01). Cancer risk (CR) for adults is below the less strict limit of 10−4, and in the case of Pb, it is even lower than values of the order of 10−6, whereas for children, CR levels exceed the standards and are of the order of 10−4, except for Pb. For all metals except Cr, the health risk was higher in 2013 than in 2018.

Life-Cycle Assessment of a Rural Terraced House: A Struggle with Sustainability of Building Renovations

Contemporary research stresses the need to reduce mankind’s environmental impacts and achieve sustainability. One of the keys to this is the construction sector. New buildings have to comply with strict limits regarding resource consumption (energy, water use, etc.). However, they make up only a fraction of the existing building stock. Renovations of existing buildings are therefore essential for the reduction of the environmental impacts in the construction sector. This paper illustrates the situation using a case study of a rural terraced house in a village near Brno, Czech Republic. It compares the life-cycle assessment (LCA) of the original house and its proposed renovation as well as demolition followed by new construction. The LCA covers both the initial embodied environmental impacts (EEIs) and the 60-year operation of the house with several variants of energy sources. The results show that the proposed renovation would reduce overall environmental impacts (OEIs) of the house by up to 90% and the demolition and new construction by up to 93% depending on the selected energy sources. As such, the results confirm the importance of renovations and the installation of environmentally-friendly energy sources for achieving sustainability in the construction sector. They also show the desirability of the replacement of inefficient old buildings by new construction in specific cases.

Hydrochemistry of the Tuxertal, NW Tauern Window, Austria: water use and drinking water supply in an alpine environment

ABSTRACT In the Tuxertal (Tux Valley, Austria), like in other Alpine regions, drinking water supply is predominantly organised privately or in cooperatives from nearby springs. Currently used springs may become unsuitable in future due to increasingly strict legal limits and changes in the water balance caused by climate change. In this study, the Tuxbach catchment area (135 km2) is examined by a reference-date measurement. Within 11 days, 153 springs and creeks were sampled to evaluate their appropriateness. All results of critical parameters for the drinking water supply are summarized and displayed in a hydrochemical map. Locally the groundwater composition differs due to various changes of petrographic units. Analysis results are statistically evaluated and characteristic values derived from six rock types. It becomes evident that apart from ammonium and arsenic, legal limits are mostly met. Low discharge rates present the major challenge for drinking water supply in future.

Design criteria of solid‐state circuit breaker for low‐voltage microgrids

Solid-state circuit breakers (SSCB) show great promise to become the key element in the protection of low-voltage direct current microgrids. SSCBs operate in the microsecond range and employ semi-conductor devices that have strict safe operation area limits. Therefore, the design of the SSCB needs to consider the effects of fault detection delays and semi-conductor safe operation area limitations. This paper derives SSCB design criteria that consider the effect of different detection methods with different detection delays under varying system constraints. The design space is investigated in a sensitivity analysis, which provides insights into the operation boundaries of SSCB and explains how a combination of fault detection methods can reduce the SSCB size. The insights from the theoretical and sensitivity analysis are used to propose an SSCB design flowchart. SSCB prototype is developed and tested in different scenarios under nominal grid voltage and current. The derived design constraints can be used for efficient SSCB design and also to evaluate the effects of different protection schemes on the required SSCB size.

Labour and the Patriot Game

AbstractThe Labour Party has recently been advised to showcase its patriotism and let the electorate know it is proud to be British. This is never bad advice for a mainstream political party with designs on power and certainly Labour in the past has enjoyed electoral success when its redistributionist policies have sprung, at least in part, from an obvious love of country. There's a certain urgency, too, in the suggestion, since the Corbyn leadership convinced many former Labour voters that the party was careless about a British identity and perhaps even hostile to British interests. Nevertheless, it would be foolish for Keir Starmer's Labour Party to enter into a destructive competition with the Tories to see who looks better with the national flag. For reasons which the article explores, there are strict limits beyond which a social democratic party would not care to go in such a contest. But this ought not matter. Voters do not want to see Labour leaders telling them how patriotic they are. They are content to be shown. This article surveys the history and looks at some possibilities inherent in Labour and the patriot game.

Testing the Bioeconomic Options of Transitioning to Solid Recovered Fuel: A Case Study of a Thermal Power Plant in Slovakia

This paper deals with the state and perspectives of bioenergy development in the context of exploiting the potential of available natural resources. We analyse the economic benefits of transitioning to alternative biofuel within the research task in cooperation with the Vojany black coal power plant. Within the applied methodology, a non-parametric data envelopment analysis method was used to confirm the most economically efficient types of fuels used in the combustion process. The assumption of fuel efficiency was confirmed by testing fuel combustion combinations directly in the power plant. The transition to 100% combustion of solid recovered fuel creates the potential for sustainable production of the analysed power plant and compliance with the current emission values of basic pollutants and new stricter limits, which will be binding in the EU from August 2021. The proposed solutions were analysed by Monte Carlo simulation. An estimate of the economic results achieved by the power plant was simulated, assuming a complete transition to solid recovered fuel. The results of the study support the feasibility of creating a circular waste management market, with the Vojany black coal power plant as the largest user of solid recovered fuel in Slovakia and abroad.