•Wavy vertical wall microchannel configuration reduce flow boiling instability•Increased waviness leads to smaller confined bubbles unlike straight microchannel•Substrate material and its thickness ...influence bubble size and flow pattern•Mostly mist vapor and dispersed bubbly flow patterns observed in wavy microchannel
Three-dimensional numerical study on two-phase flow boiling in rectangular microchannel with wavy vertical wall configuration is considered that can be utilized for heat dissipation in high flux electronics devices. Straight and wavy microchannels are considered for comparison and analysis. Under conjugate heat transfer situation, effect of flow boiling instability in straight and wavy microchannel is numerically studied using water as the working fluid. Behaviour of bubble growth rate and two-phase flow pattern in straight and wavy microchannel are investigated for a wide range of parameters such as waviness (γ ~ 0 - 0.267), substrate thickness to channel height ratio (δsf ~ 1 and 5), wall to fluid conductivity ratio (ksf ~ 22 - 646), and mass flux (G ~ 118 - 590 kg/m2s). It is found that smaller bubbles are formed in wavy microchannel while confined and elongated bubbles are formed in straight microchannel which often causes flow clogging and premature dryout. The work also presents a comparative analysis between single-phase and two-phase flow boiling cooling technique in straight and wavy microchannel under same geometrical parameters and applied heat flux.
Display omitted
Display omitted
•Conjugate heat transfer in liquid-vapor two-phase flow in microtube is studied.•Volume of fluid model along with phase change model is used in this problem.•Effect of mass flux, wall ...material conductivity and its thickness are explored.•Effect of conjugate heat transfer on growth and motion of bubble is explored.•Performance of microtube improved greatly using flow boiling cooling technique.
Flow boiling in microchannel is a promising way of high heat flux removal. In account of this, numerous experimental and numerical studies have been performed on flow boiling in conventional as well as in microchannels focusing on heat transfer, bubble dynamics and flow pattern while studies on conjugate heat transfer in flow boiling are yet to be explored. This work presents a systematic three-dimensional numerical study of conjugate effect of heat transfer in two-phase flow in a microtube subjected to constant wall heat flux. Volume of fluid (VOF) model along with phase change model are used to capture bubble shape and flow pattern. Water enters the microtube at a temperature of 300 K. The effect of (i) wall to fluid conductivity ratio (ksf), (ii) wall thickness to inner radius ratio (δsf), and (iii) inlet mass flux (G) in unsteady flow boiling condition are explored. Transformation of nucleating bubbles into elongated bubbles are characterised in terms of wall thickness (δsf) and its material conductivity (ksf). The results indicate that bubble length increases with increasing wall material conductivity but decreases with increasing wall thickness as well as mass flux. Growth and motion of vapor bubbles due to phase change are also explored. Comparison between single and two-phase flow under conjugate heat transfer scenario is also discussed.
This paper endeavors to explore the sustainable container shipping problem considering fuel bunker management and provide adequate recovery policies for countering disruption within maritime ...transportation. This paper addresses the environmental concerns related to fuel consumption and carbon emission within shipping operations and simultaneously presents strategies for countering disruption within the maritime transportation domain. Several studies addressed bunker fuel management strategies, but overlooked the need for integrating it with shipping operations. This paper aims to bridge this research gap by proposing a novel mathematical model and presenting a heuristic procedure combined with a variable neighborhood search algorithm for maximizing the shipping company's profitability, while addressing the vessel routing and scheduling decisions, container loading and unloading operations, selection of bunkering ports, and determining bunkered amount for heavy fuel oil and marine diesel oil. Recovery strategies such as port swapping and rescheduling of vessel route are considered to deal with disruptions related to weather adversities. An illustrative example is presented depicting the realistic scenario and providing results associated with ship routes, vessel speed, bunkering ports, bunkered amounts, fuel consumed by the vessel on each sailing leg, arrival and departure time of the ships, etc. Insights obtained from the analysis performed based on the fuel price, ship's bunkering capacity, adverse weather conditions on various routes, port closure, carbon tax, and fuel consumption provide useful information for shipping company managers. Managerial implications are presented with regard to the impact of fuel prices and carbon tax on shipping operation from the perspective of overall operational cost. Moreover, the results provide important policy insights for shipping company managers in terms of possessing alternate vessel route options for normal scenario and disrupted scenarios including weather adversities on sailing leg or port closure.
The looming problem of resistance to antibiotics in microorganisms is a global health concern. The drug-resistant microorganisms originating from anthropogenic sources and commercial livestock ...farming have posed serious environmental and health challenges. Antibiotic-resistant genes constituting the environmental "resistome" get transferred to human and veterinary pathogens. Hence, deciphering the origin, mechanism and extreme of transfer of these genetic factors into pathogens is extremely important to develop not only the therapeutic interventions to curtail the infections, but also the strategies to avert the menace of microbial drug-resistance. Clinicians, researchers and policymakers should jointly come up to develop the strategies to prevent superfluous exposure of pathogens to antibiotics in non-clinical settings. This article highlights the present scenario of increasing antimicrobial-resistance in pathogenic bacteria and the clinical importance of unconventional or non-antibiotic therapies to thwart the infectious pathogenic microorganisms.
The exponential growth of pollutant discharges into the environment due to increasing industrial and agricultural activities is a rising threat for human health and a biggest concern for ...environmental health globally. Several synthetic chemicals, categorized as potential environmental endocrine-disrupting chemicals (EDCs), are evident to affect the health of not only livestock and wildlife but also humankind. In recent years, human exposure to environmental EDCs has received increased awareness due to their association with altered human health as documented by several epidemiological and experimental studies. EDCs are associated with deleterious effects on male and female reproductive health; causes diabetes, obesity, metabolic disorders, thyroid homeostasis and increase the risk of hormone-sensitive cancers. Sewage effluents are a major source of several EDCs, which eventually reach large water bodies and potentially contaminate the drinking water supply. Similarly, water storage material such as different types of plastics also leaches out EDCs in drinking Water. Domestic wastewater containing pharmaceutical ingredients, metals, pesticides and personal care product additives also influences endocrine activity. These EDCs act
various receptors through a variety of known and unknown mechanisms including epigenetic modification. They differ from classic toxins in several ways such as low-dose effect, non-monotonic dose and trans-generational effects. This review aims to highlight the hidden burden of EDCs on human health and discusses the non-classical toxic properties of EDCs in an attempt to understand the magnitude of the exposome on human health. Present data on the environmental EDCs advocate that there may be associations between human exposure to EDCs and several undesirable health outcomes that warrants further human bio-monitoring of EDCs.
Purpose
This paper aims to emphasize on studying various geometrical modification performed in wavy and raccoon microchannel by manipulating parameters, i.e. waviness (γ), expansion factor (α), wall ...to fluid thermal conductivity ratio (ksf), substrate thickness to channel height ratio (dsf) and Reynolds number (Re) for obtaining optimum parameter(s) that leads to higher heat dissipation rate.
Design/methodology/approach
A three-dimensional solid-fluid conjugate heat transfer numerical model is designed to capture flow characteristics and heat transfer in single-phase laminar flow microchannels. The governing equations are solved using finite volume method.
Findings
The results are presented in terms of average base temperature, average Nusselt number, pressure drop, dimensionless local heat flux, dimensionless wall and bulk fluid temperature, local Nusselt number and performance factor including axial conduction number. Heat dissipation rate with raccoon microchannel configuration is found to be higher compared to straight and wavy microchannel. With waviness of γ = 0.167, and 0.267 in wavy and raccoon microchannel, respectively, performance factor attains maximum value compared to other waviness for all values of Reynolds number. It is also found that the effect of axial wall conduction in wavy and raccoon microchannel is negligible. Additionally, thermal performance of wavy and raccoon microchannel is compared with straight microchannel.
Practical implications
In recent past years, much complex design of microchannel has been proposed for heat transfer enhancement, but the feasibility of available manufacturing techniques to fabricate complex geometries is still questionable. However, fabrication of wavy and raccoon microchannel is easy, and their heat dissipation capability is higher.
Originality/value
This makes the difference in wall and bulk fluid temperature smaller. Thus, present work highlighted the dominance of axial wall conduction on thermal and hydrodynamic performance of wavy and raccoon microchannel under conjugate heat transfer situation.
•Effective and practical framework for green reverse logistics network design.•A multi-period MILP model accounting locations, transportation, remanufacturing.•Accounted carbon emissions from ...facilities and transportation.•The effect of carbon tax on optimal decisions is presented.•Sensitivity of optimal decisions with respect to problem parameters is analysed.
Reverse logistics network design (RLND) is getting momentum as more organizations realize the benefits of recycling or remanufacturing of their end-of-life products. Similarly, there is an impetus for organizations to become more environmentally conscious or green. This environmental context has driven many organizations to invest in green technologies, with a recent emphasis on reducing greenhouse gas emissions. This environmental investment situation and decision can be addressed through the integration of facility location, operational planning, and vehicle type selection, while simultaneously accounting for carbon emissions from vehicles, inspection centers, and remanufacturing centers in a reverse logistics (RL) context. In the current study, we present a mixed-integer linear programming (MILP) model to solve a multi-tier multi-period green RL network, including vehicle type selection. This research integrates facility locations, vehicle type selection with emissions producing from transportation and operations at various processing centers. Prior research does not account for carbon emissions for this design problem type. Valuable managerial insights are obtained when incorporating carbon emissions cost.
As electric vehicle adoption accelerates and demand increases, the inability to produce batteries in sufficient quantities has emerged as a critical bottleneck in the electric vehicle supply chain. ...Given the impending climate change crisis, resolving this bottleneck is imperative to accelerate the transition to a zero-emission electric mobility future. One potential solution is the use of robotics for fast and cost-effective assembly of batteries at scale. This study proposes a three-stage digital twin design and analysis method to develop robotic workcells for fast and cost-effective assembly of electric vehicle battery modules. Using digital twin design and simulation, robotic assembly line configurations have been developed for battery module production at different scales. Digital twin analytics was used to evaluate and optimise the proposed robotic battery assembly system for speed and cost. Industrial automation experts were consulted to further improve robotic work cell layouts to minimise investment in robots. Because digital twins of robotic workcells have been used, the configurations of the battery assembly line, as designed and validated, are ready for immediate implementation. For practitioners, this study offers heuristic methods to determine the appropriate assembly line configuration, the required number of robots and humans, for a desired production volume. For researchers, this study outlines promising areas for future investigation.
•Sources and important examples of phenolic bioactives are discussed in the review.•Crucial role of the response surface methodology in extraction of phenolic bioactives is explained in the ...review.•Green methods for extraction of phenolics are well presented along with optimized values for achieving highest yields.•Mechanism of extraction of green methods are discussed in the review.
Phenolic compounds from plant sources have significant health-promoting properties and are known to be an integral part of folk and herbal medicines. Consumption of phenolics is known to alleviate the risk of various lifestyle diseases including cancer, cardiovascular, diabetes, and Alzheimer’s. In this context, numerous plant crops have been explored and characterized based on phenolic compounds for their use as supplements, nutraceutical, and pharmaceuticals. The present review highlights some important source of bioactive phenolic compounds and novel technologies for their efficient extraction. These techniques include the use of microwave, ultrasound, and supercritical methods. Besides, the review will also highlight the use of response surface methodology (RSM) as a statistical tool for optimizing the recoveries of the phenolic bioactives from plant-based matrices.
•Two new fuzzy hybrid approaches for the strategic supplier selection problem are developed.•The first approach combines the fuzzy consensus-based possibility measure and TOPSIS method.•The second ...approach combines the fuzzy consensus-based neat OWA and goal programming model.•The CCSD model is used to compute the criteria weights.•Comparison between individual solutions and collective solution using the Levenshtein distance.
The current complexity of supply chains (SC) activities requires the need for coordination between supply chains partners to maximize the efficiency. Considered by practitioners as one of the main SC coordination problems, this paper considers the strategic supplier selection problem. Fuzzy set is used in order to address the imprecision of supply chain partners in formulating the preferences values of various selection criteria. The problem is formulated as a multi-stakeholder multi-criteria (MSMC) decision making problem and solved using two novel approaches. The first hybrid approach combines the fuzzy consensus-based possibility measure and fuzzy TOPSIS method. The second hybrid approach combines the fuzzy consensus-based neat OWA and goal programming model where, the inclusion and participation of stakeholders in the decision-making process is explicit. For each approach, the correlation coefficient and standard deviation (CCSD) based objective weight determination model is used to compute the criteria weights. To demonstrate the applicability of the proposed approaches, a simple example of strategic supplier selection problem is presented and the numerical results analyzed. Moreover, for each approach, the deviations between individual solutions and collective solution are evaluated using the Levenshtein distance. Finally, the advantages and disadvantages of each approach are listed.
PDF
