Cyclic production of biocompatible few-layer graphene ink with in-line shear-mixing for inkjet-printed electrodes and Li-ion energy storage

The scalable production of two-dimensional (2D) materials is needed to accelerate their adoption to industry. In this work, we present a low-cost in-line and enclosed process of exfoliation based on high-shear mixing to create aqueous dispersions of few-layer graphene, on a large scale with a Yw ~ 100% yield by weight and throughput of ϕ ~ 8.3 g h−1. The in-line process minimises basal plane defects compared to traditional beaker-based shear mixing which we attribute to a reduced Reynolds number, Re ~ 105. We demonstrate highly conductive graphene material with conductivities as high as σ ∼ 1.5 × 104 S m−1 leading to sheet-resistances as low as Rs ∼ 2.6 Ω □−1 (t ∼ 25 μm). The process is ideal for formulating non-toxic, biocompatible and highly concentrated (c ∼ 100 mg ml−1) inks. We utilise the graphene inks for inkjet printable conductive interconnects and lithium-ion battery anode composites that demonstrate a low-rate lithium storage capability of 370 mAh g−1, close to the theoretical capacity of graphite. Finally, we demonstrate the biocompatibility of the graphene inks with human colon cells and human umbilical vein endothelial cells at high c ∼ 1 mg ml−1 facilitating a route for the use of the graphene inks in applications that require biocompatibility at high c such as electronic textiles.publishedVersio

Precipitation from persistent extremes is increasing in most regions and globally

Extreme precipitation often persists for multiple days with variable duration but has usually been examined at fixed duration. Here we show that considering extreme persistent precipitation by complete event with variable duration, rather than a fixed temporal period, is a necessary metric to account for the complexity of changing precipitation. Observed global mean annual-maximum precipitation is significantly stronger (49.5%) for persistent extremes than daily extremes. However, both globally observed and modeled rates of relative increases are lower for persistent extremes compared to daily extremes, especially for Southern Hemisphere and large regions in the 0-45°N latitude band. Climate models also show significant differences in the magnitude and partly even the sign of local mean changes between daily and persistent extremes in global warming projections. Changes in extreme precipitation therefore are more complex than previously reported, and extreme precipitation events with varying duration should be taken into account for future climate change assessments

The Effect of Risk and Uncertainty Factors on Managerial Decision Making

This study evaluated the effect of risk and uncertainty factors on financial decision making. The long-term goals and ways for achievement are constantly attached with uncertainty since we don’t know the circumstances, either positive or negative, which happen later. Uncertainty is a key logical factor that influences the dynamic. The reason for this investigation is to check how risk and factors of uncertainty impact the financial aspects of a firm. The risk factors incorporate, financial risk, market fluctuations hazards, fluctuation of unfamiliar and loan costs. Uncertainty factors incorporate political, monetary and environmental uncertainty. The results reveal that management knowledge and expertise related to these factors are utmost important for effective decision making and sustainable growth

A Survey on Electrical Energy Storage Potential in South-East Europe to Support Transmission Network Flexibility

Electrical Energy Storage (EES) facilities have attracted a huge interest recently in increasing the operational flexibility of modern power systems. This interest is fueled by the integration of a high amount of intermittent renewable energy resources (RES) in the networks. This study has been performed to analyze and identify the potential of EES in providing the operational flexibility of power networks in 8 South-East European countries. For that purpose, a survey questionnaire was developed on EES, which was distributed in late 2017 and responses were collected in January 2018. The questionnaires collected information on existing EES capacities, the required amount of EES for flexible operation and the future potential of these resources. Additional key information was collected about these resources, such as the characteristics, location and network services obtained from these resources, as well as the influential market participants to provide these services in the network. This study will facilitate the cross-border management of RES by increasing the operational flexibility of the transmission network in South-East Europe

Knowledge, Practices, and Risk Perception Associated with Foodborne Illnesses among Females Living in Dubai, United Arab Emirates

Foodborne illnesses are a widespread and growing public health concern worldwide. The aim of this study was to investigate the knowledge, practices, and risk perception pertaining to food safety among females living in Dubai, United Arab Emirates (UAE). A questionnaire-based cross-sectional study was undertaken consisting of 827 female participants between January to April 2020. The study showed that the overall food safety risk perception was below satisfactory (53.3%). The highest score was seen in the “recognition of foodborne illnesses” aspect (76.7%). The participants were aware of “personal hygiene and cleaning” (61.7%), “cross-contamination prevention” (62.5%), “food purchasing” (60.0%), and “storage of frozen foods” (55.6%). The participants had a low level of knowledge pertaining to “food cooking” (26.0%) and “risk of microbiological infection” (13.3%). There was a statistically significant (p ≤ 0.05) association between knowledge and practices of respondents with employment status, age, and educational levels. In conclusion, the female respondents might act as vehicles for the spread of foodborne illnesses. To reduce this risk, providing food safety awareness programs to this portion of the population is paramount

The performance of γ-Fe2O3 and xGnP nanofluid in hard turning of AISI 420 stainless steel

Evaluation of the performance of two nanofluids (?-Fe2O3 and xGnP) was investigated in hard turning of AISI 420 stainless steel (48 ±2 HRC) using coated carbide tools (KC5010) under minimum quantity lubrication. The investigation considered the tool life, cutting force and surface roughness responses at medium cutting speed and feed rate (135 m/min, 0.20 mm/rev) and constant depth of cut (0.2 mm). The concertation of nanofluids are 0.4% (1.6 g), 0.8% (3.2 g), and 1.2% (6.4 g) by weight of ?-Fe2O3 and xGnP. The results revealed the overall better performance of ?-Fe2O3 compared to xGnP. The better performance of ?-Fe2O3 was achieved at 0.8% concentration as it leads to the lowest surface roughness (0.18 µm), and cutting force (FX= 195 N) and highest tool life (8.31 min). However, the 0.4% of xGnP lead to the worst performance as it had the cutting force (FX= 285 N) and lowest tool life (3.27 min) while, highest surface roughness (0.26 µm) for both 0.4 ?-Fe2O3 and 0.8 xGnP. It is expected that this study finishings will improve the cutting condition which leads to the achievement of good geometry, enhancement of environmental friendliness, improvement of surface integrity, saving of time and reduction of cost in the manufacturing industries of hardened materials

Comparison between synthetic inertia and fast frequency containment control based on single phase EVs in a microgrid

The increasing share of distributed and inertia-less resources entails an upsurge in balancing and system stabilisation services. In particular, the displacement of conventional generation reduces the available rotational inertia in the power system, leading to high interest in synthetic inertia solutions. The objective of this paper is twofold: first, it aims to implement and validate fast frequency control and synthetic (virtual) inertia control, employing single phase electric vehicles as flexibility resources. Second, it proposes a trade-off analysis between the two controllers. The interdependency between frequency containment and synthetic inertia control on the transient frequency variation is shown analytically. The capabilities and limits of series produced EVs in providing such services are investigated, first on a simulation based approach and subsequently by using real hardware. The results show that fast frequency control can improve the transient frequency behaviour. However, both on the simulation and on the experimental level, the implementation of synthetic inertia control is more challenging. In fact, due its derivative nature and the system dynamics, its performance is limited. Furthermore, the crucial importance of the EVs’ response time for both controllers is highlighte