Mathematical analysis of the turbine coefficient of performance for tidal stream turbines

Unregulated water currents such as tides and ocean currents include energy that could be utilized for electricity production. These currents can be seen as dead bodies of water with potential energy, driven by gravity or alive moving with a kinetic energy (KE). Tidal stream turbines are a relatively new technology for extracting KE from tidal currents, which is currently in progress from development stage to industrial execution. One of the most important factors in tidal power analysis is the rotor efficiency coefficient or turbine coefficient of performance (λ). It depends on the rotor blade geometry and water velocity. This article presents a mathematical description of good interpolating functions which describe this coefficient analytically, for tidal stream turbines. Nonlinear curve-fitting solver in least-squares sense has been used in this study. Various interpolation functions have been proposed. The proposed mathematical descriptions can be very helpful for tidal power analysis and output power estimation

Context Mining of Sedentary Behavior for Promoting Self-Awareness Using Smartphone

Sedentary behaviour is increasing due to societal changes and is related to prolonged periods of sitting. There is sufficient evidence proving that sedentary behaviour has a negative impact on people’s health and wellness. This paper presents our research findings on how to mine the temporal contexts of sedentary behaviour by utilizing the on-board sensors of a smartphone. We use the accelerometer sensor of the smartphone to recognize user situations (i.e., still or active). If our model confirms that the user context is still, then there is a high probability of being sedentary. Then, we process the environmental sound to recognize the micro-context, such as working on a computer or watching television during leisure time. Our goal is to reduce sedentary behaviour by suggesting preventive interventions to take short breaks during prolonged sitting to be more active. We achieve this goal by providing the visualization to the user, who wants to monitor his/her sedentary behaviour to reduce unhealthy routines for self-management purposes. The main contribution of this paper is two-fold: (i) an initial implementation of the proposed framework supporting real-time context identification; (ii) testing and evaluation of the framework, which suggest that our application is capable of substantially reducing sedentary behaviour and assisting users to be active

Comparative analysis of optimal damped and undamped passive filters using MIDACO-solver

Copyright © 2022 The Authors. Harmonic pollution is one of the challenging problems facing power networks recently due to the widespread non-linear loads and inverter-based renewables. In this regard, this work presents the optimal design of damped and undamped passive filters using a solver called Mixed-Integer Distributed Ant Colony Optimisation (MIDACO). This solver is employed to obtain an optimal design strategy for single-tuned passive power filters by investigating three primary criteria – minimisation of active power losses of the Thevenin’s resistor, maximisation of the true power factor, and maximisation of the transmission efficiency. Several constrictions associated with the designed filters have been considered, in which the global maximum or minimum criterion was attained by retaining the quality factors of the designed filters within a particular range, damping harmonic resonance, achieving a permissible range of the power factor, limiting voltage harmonic distortion by complying with IEEE Std. 519–2014 restrictions. Besides, the performance limits of capacitors operating in distorted systems have been met while complying with IEEE Std. 18–2012. Further, the results obtained using the MIDACO solver in four different case studies are compared to those obtained using particle swarm optimisation and genetic algorithm. In addition, this work depicts the damping resistor of the inductance in the single-tuned filters. The benefits and drawbacks of damping over an undamped filter are discussed. Finally, the results validate the effectiveness of the MIDACO solver employed in this paper.The authors did not receive support from any organisation for the submitted work

Digital Forensic Acquisition and Analysis of Discord Applications

Digital forensic analyses are being applied to a variety of domains as the scope and potential of digital evidence available is vast. The importance of forensic analyses of web-based devices and tools is increasing, coinciding with the rise in online criminal activity. Discord - an application that allows text, image, video, and audio communication using VoIP - has become increasingly popular and is consequently subject to increased use by cybercriminals. While researching Discord servers and forensic artefacts, it is apparent that there is limited literature and experimentation in this domain. This paper presents our research into digital forensic analyses of Discord client-side artefacts and presents DiscFor, a novel tool designed for the extraction, analysis, and presentation of Discord data in a forensically sound manner. DiscFor creates a safe copy of said data, presenting the current cache state and converting data files into a readable format

How effective are the components of active management of the third stage of labor?

BACKGROUND: Active management of the third stage of labor is recommended for the prevention of post-partum hemorrhage and commonly entails prophylactic administration of a uterotonic agent, controlled cord traction, and uterine massage. While oxytocin is the first-choice uterotonic, it is not known whether its effectiveness varies by route of administration. There is also insufficient evidence regarding the value of controlled cord traction or uterine massage. This analysis assessed the independent and combined effectiveness of all three interventions, and the effect of route of oxytocin administration on post-partum blood loss. METHODS: Secondary data were analyzed from 39202 hospital-based births in four countries and two clinical regimens: one in which oxytocin was administered following delivery of the baby; the other in which it was not. We used logistic regression to examine associations between clinical and demographic variables and post-partum blood loss ≥ 700 mL. RESULTS: Among those with no oxytocin prophylaxis, provision of controlled cord traction reduced hemorrhage risk by nearly 50% as compared with expectant management (P < 0.001). Among those with oxytocin prophylaxis, provision of controlled cord traction reduced hemorrhage risk by 66% when oxytocin was intramuscular (P < 0.001), but conferred no benefit when oxytocin was intravenous. Route of administration was important when oxytocin was the only intervention provided: intravenous administration reduced hemorrhage risk by 76% as compared with intramuscular administration (P < 0.001); when combined with other interventions, route of administration had no effect. In both clinical regimens, uterine massage was associated with increased hemorrhage risk. CONCLUSIONS: Recommendations for active management of the third stage of labor should account for setting-related differences such as the availability of oxytocin and its route of administration. The optimal combination of interventions will vary accordingly

Mapping the Interactions between a RUN Domain from DENND5/Rab6IP1 and Sorting Nexin 1

Eukaryotic cells have developed a diverse repertoire of Rab GTPases to regulate vesicle trafficking pathways. Together with their effector proteins, Rabs mediate various aspects of vesicle formation, tethering, docking and fusion, but details of the biological roles elicited by effectors are largely unknown. Human Rab6 is involved in the trafficking of vesicles at the level of Golgi via interactions with numerous effector proteins. We have previously determined the crystal structure of Rab6 in complex with DENND5, alternatively called Rab6IP1, which comprises two RUN domains (RUN1 and RUN2) separated by a PLAT domain. The structure of Rab6/RUN1-PLAT (Rab6/R1P) revealed the molecular basis for Golgi recruitment of DENND5 via the RUN1 domain, but the functional role of the RUN2 domain has not been well characterized. Here we show that a soluble DENND5 construct encompassing the RUN2 domain binds to the N-terminal region of sorting nexin 1 by surface plasmon resonance analyses

Protection and consolidation of stone heritage by self-inoculation with indigenous carbonatogenic bacterial communities

Enhanced salt weathering resulting from global warming and increasing environmental pollution is endangering the survival of stone monuments and artworks. To mitigate the effects of these deleterious processes, numerous conservation treatments have been applied that, however, show limited efficacy. Here we present a novel, environmentally friendly, bacterial self-inoculation approach for the conservation of stone, based on the isolation of an indigenous community of carbonatogenic bacteria from salt damaged stone, followed by their culture and re-application back onto the same stone. This method results in an effective consolidation and protection due to the formation of an abundant and exceptionally strong hybrid cement consisting of nanostructured bacterial CaCO3 and bacterially derived organics, and the passivating effect of bacterial exopolymeric substances (EPS) covering the substrate. The fact that the isolated and identified bacterial community is common to many stone artworks may enable worldwide application of this novel conservation methodology.This work was supported by the Spanish Government (Grants MAT2012-37584, CGL2012-35992 and CGL2015-70642-R), the Junta de Andalucía through Proyecto de excelencia RNM-3493 and Project P11-RNM-7550, the Research Groups BIO 103 and RNM-179, and the University of Granada (Unidad Científica de Excelencia UCE-PP2016-05). Additional funds were provided by the Molecular Foundry (Lawrence Berkeley National Laboratory, LBNL, University of California, Berkeley, CA) for a research stay of M.S. (project #1451; User Agreement No. NPUSR009206)

The prevalence of waterpipe tobacco smoking among the general and specific populations: a systematic review

Abstract Background The objective of this study was to systematically review the medical literature for the prevalence of waterpipe tobacco use among the general and specific populations. Methods We electronically searched MEDLINE, EMBASE, and the ISI the Web of Science. We selected studies using a two-stage duplicate and independent screening process. We included cohort studies and cross sectional studies assessing the prevalence of use of waterpipe in either the general population or a specific population of interest. Two reviewers used a standardized and pilot tested form to collect data from each eligible study using a duplicate and independent screening process. We stratified the data analysis by country and by age group. The study was not restricted to a specific context. Results Of a total of 38 studies, only 4 were national surveys; the rest assessed specific populations. The highest prevalence of current waterpipe smoking was among school students across countries: the United States, especially among Arab Americans (12%-15%) the Arabic Gulf region (9%-16%), Estonia (21%), and Lebanon (25%). Similarly, the prevalence of current waterpipe smoking among university students was high in the Arabic Gulf region (6%), the United Kingdom (8%), the United States (10%), Syria (15%), Lebanon (28%), and Pakistan (33%). The prevalence of current waterpipe smoking among adults was the following: Pakistan (6%), Arabic Gulf region (4%-12%), Australia (11% in Arab speaking adults), Syria (9%-12%), and Lebanon (15%). Group waterpipe smoking was high in Lebanon (5%), and Egypt (11%-15%). In Lebanon, 5%-6% pregnant women reported smoking waterpipe during pregnancy. The studies were all cross-sectional and varied by how they reported waterpipe smoking. Conclusion While very few national surveys have been conducted, the prevalence of waterpipe smoking appears to be alarmingly high among school students and university students in Middle Eastern countries and among groups of Middle Eastern descent in Western countries