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This paper provides experimental data on the temperature rise during granular flows in a small-scale rotating drum due to heat generation. All heat is believed to be generated by conversion of some mechanical energy, through mechanisms such as friction and collisions between particles and between particles and walls. Particles of different material types were used, while multiple rotation speeds were considered, and the drum was filled with different amounts of particles. The temperature of the granular materials inside the rotating drum was monitored using a thermal camera. The temperature increases at specific times of each experiment are presented in form of tables, along with the average and standard deviation of the repetitions of each setup configuration. The data can be used as a reference to set the operating conditions of rotating drums, in addition to calibrating numerical models and validating computer simulations. This project is funded through Marie SKŁODOWSKA-CURIE Innovative Training Network MATHEGRAM1, the People Programme (Marie SKŁODOWSKA-CURIE Actions) of the European Union's Horizon 2020 Programme H2020 under REA grant agreement No. 813202. Dr. Franci acknowledges the support from MCIN/AEI/10.13039/501100011033 and FEDER Una manera de hacer Europa for funding his work via project PID2021-122676NB-I00. Prof. Oñate acknowledges the Severo Ochoa Programme through the Grant CEX2018-000797-S funded by MCIN/AEI/10.13039/501100011033.

The building Life Cycle Assessment (LCA) applied to buildings requires collecting and organizing large quantities of data over all building life cycles. To overcome specific difficulties related to the system boundaries definition and life cycle inventory stages, the literature recognizes that systematic building decomposition methods (SBDM) can be used to classify building components, elements and materials, as well as to increase the reliability and transparency of LCA results, particularly for embodied carbon and other environmental impacts. In this paper developed in the context of the research project IEA EBC Annex 72, the authors aim to provide a basis for understanding how different SBDMs decompose a building and classify its parts. This study analyses the implications of using different SBDM along the steps of an LCA study. Such as to support transparent and comprehensible (de)composition of the life cycle inventory (LCI), definition of service lives for different building parts or clear and comparable communication of assessment results and environmental hotspots particularly when using digital tools to conduct LCA. The study analyses 12 national SBDMs used in participating countries of IEA EBC Annex 72. To showcase the implications of SBDMs in building LCA practice, an office building was used as a common case study for applying the different SBDM approaches. Differences were identified among the decomposition levels and the consequences of these differences on the LCI organization. Thus, some of the main contributions to this study are the investigation of different SBDM approaches for improving the design workflows, by discussing BIM model definitions and the recommendation to use hierarchically based methods to allow the building elements and materials decomposition.

© 2022 Elsevier B.V.Lignocellulosics are abundant carbon sources in nature, therefore they gain increasing attention in biotechnology for production of value-added chemicals. In this proof-of-concept study highlighting the techno-economic potential of L-3,4-dihydroxyphenylalanine (L-DOPA) production from lignocellulosic agro-waste hazelnut husk, first an exploratory model-based optimization was used to release the sugar content of the husk whilst maximizing sugar concentration. The sugar hydrolysate was then evaluated as a feedstock for production using an engineered Corynebacterium glutamicum strain. Optimal treatment conditions were found by Kriging model as 12.5% husk load with 3.8% acid for 50 min at 121 °C, which gave a hydrolysate of 27.67 g L−1 reducing sugar with a yield of 11.07 g sugar/100 g husk. When this hydrolysate was used as the sole carbon source during fermentative production, 20 ± 0.4 mg L−1 of L-DOPA was produced. When cells grown on husk hydrolysate were used for whole-cell biotransformation, a titer of 82 ± 1 mg L−1 of L-DOPA was obtained. From an economical point of view, the titer obtained during fermentative production would allow production of L-DOPA from hazelnut husk right around the breakeven point. However, further engineering of the strains and optimization of bioprocess conditions, would make it possible to bring the revenues to higher levels.

Grid-scale inter-seasonal energy storage and its ability to balance power demand and the supply of renewable energy may prove vital to decarbonise the broader energy system. Whilst there is a focus on techno-economic analysis and battery storage, there is a relative paucity of work on grid-scale energy storage on the system level with the required temporal resolution. Here, we evaluate the potential of power-to-gas-to-power as inter-seasonal energy storage technology. Our results suggest that inter-seasonal energy storage can reduce curtailment of renewable energy, and overcapacity of intermittent renewable power. Importantly, grid scale energy storage assumes a critical role especially when the technology options for dispatchable power are limited. It appears that neither high CAPEX nor low round-trip efficiency preclude the value of the technology per se, however the rate of charge and discharge of the technology emerges as key technical characteristic. This study emphasises the rising importance of balancing seasonality in energy systems characterised by a high penetration of renewable energy, and prompts questions regarding sector integration and resilient decision-making toward a zero-carbon economy.

The chemical engineering journal 446, 137104 (2022). doi:10.1016/j.cej.2022.137104, Adsorptive separation of propylene and propane, an important step of polypropylene production, is more energy-efficient than distillation. However, the challenge lies in the design of an adsorbent which exhibits both high selectivity and uptake. Herein, we hypothesise that enhancing the propylene affinity of the adsorption sites while keeping a suitable pore size can address this challenge. To do so, we performed silver exchange of a commercial zeolite Y, thereby making the adsorbent design easily scalable. We characterised the adsorbent using analytical, spectroscopic and imaging tools, tested its equilibrium and dynamic sorption properties using volumetric and gravimetric techniques and compared its performance to those of state-of-the-art adsorbents as well as other silver-functionalised adsorbents. The silver-exchanged zeolite Y (Ag-Y) exhibited one of the best selectivity vs uptake performances reported so far. Ag-Y also displayed fast adsorption kinetics and reversible propylene sorption, making it a promising new benchmark for propylene/propane separation. Synchrotron-based pair distribution function analyses identified the silver cations’ location which confirmed that the silver sites are easily accessible to the adsorbates. This aspect can, in part, explain the propylene/propane separation performance observed. The overall design strategy proposed here to enhance sorption site affinity and maintain pore size could be extended to other adsorbents and support the deployment of adsorption technology for propylene/propane separation., Published by Elsevier, Amsterdam

Microplastics (MPs) have been detected globally in the marine environment. MP polymers of various kinds have different toxicity potentials when decomposed into monomers. Also, the toxicity of MPs is influenced by the particle size distribution of MPs. Based on these parameters, a semi-quantitative risk assessment model has been developed in this study to rank MP polymers of potential health concern emerging from marine exposure pathways. A screening strategy was used to categorize three probability factors and two impact factors and calculate the final risk scores. Four different scenarios were assessed to investigate the influence of risk factors on the model output. The screening strategy prioritised PUR, PVC, PAN, ABS, PMMA, SAN, TPU, UP, PET, PS, and HDPE as the top-ranking polymers of concern (descending order). The sensitivity analysis revealed parameters that influenced the final risk score were hazard score based on monomer classification (RF5 coefficient +0.60)> particle size distribution of MPs (RF4 +0.54)> annual global waste generation (RF1 +0.52)> status of degradation in the marine environment (RF3 +0.32)> mean density of polymers (RF2 +0.16). The outcome of this study can inform the scientific community and the policymakers for better management of MPs where regulation and guidelines need to be considered. ispartof: JOURNAL OF HAZARDOUS MATERIALS vol:429 ispartof: location:Netherlands status: published

Phosphorus (P) can be effectively recovered from sewage sludge ash (SSA) by applying wet chemical extraction techniques. However, considerable amounts of heavy metals can be co-extracted depending on the type of extraction liquid used. In this study, the influence of the incineration temperature on the ash mineralogy and related P and heavy metal extraction using sulfuric acid, hydrochloric acid, oxalic acid and sodium hydroxide was studied. Results showed that the P extraction efficiency with sodium hydroxide decreased with increasing incineration temperature, related to a decrease in Al/Fe-phosphates in the SSA. Furthermore, P extraction efficiency for the acidic extraction liquids reached a maximum for SSA obtained around 850 °C (> 86% P extracted). Heavy metal co-extraction generally decreased with increasing incineration temperature, which could be linked to the immobilization of the heavy metals in the SSA matrix. For all extraction liquids considered, the lowest heavy metal co-extraction was found in SSA samples obtained at 1000 °C (< 21% total heavy metals extracted). However, the incorporation of P into silicate melt agglomerates at that incineration temperature reduced the P extraction. As a result, an incineration temperature in the range 800 – 850 °C offered a good trade-off between high P extraction and low heavy metal co-extraction. ispartof: Journal of Environmental Chemical Engineering vol:9 issue:6 status: published

A significant uncertainty which remains for CO 2 sequestration, is the effect of natural geological heterogeneities and hysteresis on capillary trapping over different length scales. This paper uses laboratory data measured in cores from the Goldeneye formation of the Captain D Sandstone, North Sea in 1D numerical simulations to evaluate the potential capillary trapping from natural rock heterogeneities across a range of scales, from cm to 65m. The impact of different geological realisations, as well as uncertainty in petrophysical properties, on the amount of capillary heterogeneity trapping is estimated. In addition, the validity of upscaling trapping characteristics in terms of the Land trapping parameter is assessed. The numerical models show that the capillary heterogeneity trapped CO 2 saturation may vary between 0 and 14% of the total trapped saturation, depending upon the geological realisation and petrophysical uncertainty. When upscaling the Land model from core-scale experimental data, using the maximum experimental Land trapping parameter could increase the expected heterogeneity trapping by a factor of 3. Conversely, depending on the form of the imbibition capillary pressure curve used in the numerical model, including capillary pressure hysteresis may reduce the heterogeneity trapping by up to 70%.

Steviol glycosides are fully deglycosylated to steviol in the presence of bacterial populations that were isolated from different soil samples. Heating (20 min at 80 °C) or boiling (10 min at 100 °C) of soils had little effect on the steviol formation. It is suggested that bacteria that survived with highly resistant spores are responsible for the deglycosylation of steviol glycosides. A bio-organic preparation method for steviol was developed which had a total yield of 90%. Beside deglycosylation, other reactions also occur. The steviol formed can be degraded. Under anaerobic conditions, rebaudioside A was not hydrolyzed while stevioside was degraded to steviol via rubusoside. Moreover, after an extended incubation (4 weeks) and repetitive sub-cultivation, a bacterial community was selected that converted steviol glycosides to a new and unknown ketone, given the nickname Monicanone. It appeared to be the steviol nucleus without the A-ring that underwent a Walden inversion at its original C-10. A second and related unknown compound could be isolated from an impure preparation of Monicanone by chromatographic separation and purification; this compound was a reduced form of Monicanone and named Monicanol. Steviol glycosides that were incubated with a UASB effluent of an industrial wastewater treatment system – supplemented or not – with sludge of a lab scale nitrification or denitrification unit – were completely degraded via steviol and Monicanone.

Net zero energy buildings (NZEBs) are energy efficient buildings that incorporate renewable energy generation systems so as to produce sufficient renewable energy to at least offset the total amount of non-renewable energy used by the building on an annual basis. NZEB technologies have widespread commercial and residential application, but their feasibility and efficacy in the livestock sector in support of sustainable intensification have received little attention. This study quantifies the potential for such technologies to improve sustainability outcomes in the livestock sector based on an ISO 14044-compliant life cycle assessment of a pilot net zero energy laying hen facility in Alberta, Canada compared to a conventional facility. It was found that direct energy inputs account for 6.47% and 31.64% of the life cycle cumulative energy use of egg production in NZE and non-NZE hen housing, respectively. Average infrastructure-related contributions to the life cycle impacts of egg production are only 4.34% and 1.94% for the NZE and non-NZE barns, but NZE technologies reduce the net impacts of egg production by 0.89–64.82%. The environmental impact payback time for the NZE barn (30-year lifespan) ranges from 1.38 to 20.66 years, considering the largely fossil fuel-based electricity grid in Alberta, which indicates that non-trivial environmental benefits would accrue across impact categories considered. However, this could vary considerably elsewhere depending on the types and amounts of green energy utilized in regional grid mixes. The type and availability of renewable energy resources that are integrated into NZE barns will similarly be important in determining the potential of such technologies to support sustainable intensification in this sector.

The complex composition of waste electrical and electronic equipment (WEEE) plastics represents a challenge during post-consumption plastic recycling. A single WEEE category, e.g. large household appliances (LHA), can contain several different plastic types with overlapping material properties, making the sorting of individual plastics a challenge. Significant increases in plastic recovery rates can be expected by clustering product categories, as clustering can avoid mixing of non-compatible plastics with overlapping material properties. For this purpose, a life cycle assessment (LCA) is conducted to investigate the influence of different clustering strategies on the environmental performance of waste treatment and the production of recycled plastic from LHA waste stream. To assure comparability between waste treatment scenarios a system expansion approach is applied, and to allocate the burden of shared processes over the first and second use cycle of the material partitioning is applied. Results show that an increased separation of product clusters by plastic type can improve the plastic recovery rate from 5.8% to 47.1% and reduce the overall environmental impact, quantified with the ReCiPe (2016) method, by up to 23%. The environmental impacts of using recycled plastics from LHA waste can be reduced by 27 to 38% compared to single-use plastic. The holistic approach used in this study demonstrates (1) the potential benefits of implementing product clustering strategies for LHA plastic recycling, (2) the relevance of different allocation procedures when integrating recycling into an LCA, (3) the importance of using less virgin material and avoiding final waste treatment, and (4) the limitation of the recycling system to reduce the environmental burden associated with products. ispartof: Waste Management vol:126 pages:497-507 ispartof: location:United States status: published

Granular activated carbon (GAC) adsorption has found wide application as a treatment process for the removal of natural organic matter, small organic compounds (e.g. pesticides), inorganic compounds (e.g. heavy metals), taste and odour compounds in water over many years. During GAC operation, contaminants are adsorbed and the carbon becomes progressively saturated over time, requiring periodic regeneration of the media to restore its capacity. Chemical regeneration has been identified as an effective alternative to off-site thermal regeneration, which is the most commonly practiced carbon regeneration technique for carbon exhausted by organic contaminants. Off-site thermal regeneration poses significant disadvantages as it is a time-consuming process and represents a significant operational cost (e.g. reduced productivity) and environmental (energy/CO2) burden to water utilities. Chemical regeneration can be performed on-site, either in situ or off-line, by exposing the spent (exhausted) GAC to a selected chemical, or a combination of chemicals, to remove the adsorbed contaminants. Prior research on chemical regeneration has been limited in extent, but has considered both organic and inorganic solutions. Despite a significant number of studies, a suitable regenerant solution for desorbing a wide range of aqueous contaminants in drinking water treatment has not been identified to-date. In this paper, we provide a critical review of the performance of alternative regenerant solutions for the chemical regeneration of GAC loaded with different organic contaminants.

SARS-CoV-2 can spread by close contact through large droplet spray and indirect contact via contaminated objects. There is mounting evidence that it can also be transmitted by inhalation of infected saliva aerosol particles. These particles are generated when breathing, talking, laughing, coughing or sneezing. It can be assumed that aerosol particle concentrations should be kept low in order to minimize the potential risk of airborne virus transmission. This paper presents measurements of aerosol particle concentrations in a gym, where saliva aerosol production is pronounced. 35 test persons performed physical exercise and aerosol particle concentrations, CO2 concentrations, air temperature and relative humidity were obtained in the room of 886 m³. A separate test was used to discriminate between human endogenous and exogenous aerosol particles. Aerosol particle removal by mechanical ventilation and mobile air cleaning units was measured. The gym test showed that ventilation with air-change rate ACH = 2.2 h-1, i.e. 4.5 times the minimum of the Dutch Building Code, was insufficient to stop the significant aerosol concentration rise over 30 min. Air cleaning alone with ACH = 1.39 h-1 had a similar effect as ventilation alone. Simplified mathematical models were engaged to provide further insight into ventilation, air cleaning and deposition. It was shown that combining the above-mentioned ventilation and air cleaning can reduce aerosol particle concentrations with 80 to 90% , depending on aerosol size. This combination of existing ventilation supplemented with air cleaning is energy efficient and can also be applied for other indoor environments. ispartof: BUILDING AND ENVIRONMENT vol:193 ispartof: location:England status: published

Ketonization of (biomass) carboxylic acids is increasingly showing its potential as upgrading strategy to renewable fuels and chemicals. Due to the growing amount of recent studies, an updated and critical overview of the catalytic advancements are warranted. Metal oxide and zeolite catalysts are discussed, alongside their proposed mechanisms and elementary steps. Substrate-surface interactions, structure-function correlations and kinetic studies have contributed to a better understanding of the requirements for ketonization catalysis, though the mechanism and rate-determining step(s) are still under debate. As a result, targeted modifications to improve catalytic performance are being established. Furthermore, substrate properties such as chain length, branching, unsaturation and additional functionalities have been identified as crucial for their reactivity. However, additional research is necessary to better integrate ketonization into future biorefineries. This includes development of kinetic models for oleochemicals conversion, catalyst design and regeneration. Finally, techno-economic and sustainability assessments are lacking to incentivize industrial implementation.

As our understanding of the interactions present in socio-ecological systems advance, emulation modeling can help reduce the complexity and required computational resources of the models used to represent these systems. While emulation is commonly used in model meta-analyses and parameterization, it has been less explored in the context of environmental management. In this research, I analyze the reflections of a group of watershed modelers on environmental model emulation. I find that decreased simulation run-times are an important motivation because emulators enable stakeholders to interact directly with the model. However, participants also reported that criteria for an emulator in an environmental management context should also assess its capability to act as a platform for learning and to manage stakeholder perceptions of the modeling process. Further, at the science-action interface, stakeholder perceptions play a significant role in the approach to model emulation through determining acceptable levels complexity in model processes and inputs. Accepted version

The green synthesis of engineered nanomaterials (NMs) has deserved an enormous academic interest and huge financial investments during the last decades. However, this prominent position has not been followed by the rapid commercialization of NMs for real applications thus rendering their practical usefulness very doubtful and the appropriateness of novel investments in the field highly questionable. The present manuscript presents the first scientometric study on the green synthesis of NMs aiming to survey the scientific progress in this particular field and identify its main gaps while providing applicable suggestions to facilitate the knowledge transfer from laboratories to real full scale production and applications. The research on green synthesis of nanomaterials published in Web of Science during the period 1991–2019 is here carefully analyzed. Overall, 9 scientometric indicators are employed to interpret the results retrieved from the 8761 documents collected. It is found that 107 countries and nearly 22,400 authors have contributed to this subject, hence highlighting the relevance of this topic. The keywords spectrum is dominated by the term “nanoparticle” which full adoption takes place at the beginning of the 21st century. Some few years later, a batch of words like “silver nanoparticle”, “gold nanoparticle” and “nanocomposite” reaches a significant impact reflecting the emergence of commercial applications for these nanomaterials. It is only in 2009 that the keyword “green synthesis” gains strength, followed then by “biosynthesis” in 2010, making it evident a trend towards environmentally friendly reagents. The number of publications on green synthesis of nanomaterials displays up to now a sigmoidal like growth pattern, which points actually to a decrease on new arrivals, thus suggesting a possible forthcoming decline in this field. However, the analysis carried out in the present work allows identifying various gaps related to sustainability, which, if appropriately addressed, may contribute to a resurgence of the research on nanomaterials synthesis while fostering more frugal approaches on material synthesis tendencies.

Governments and social benefit organizations are expected to consider evidence in decision-making. In development and sustainability, evidence spans disciplines and methodological traditions and is often inconclusive. Graphical models are widely promoted to organize interdisciplinary evidence and improve decision-making by considering mediating variables. However, the reproducibility, objectivity and benefits for decision-making of graphical models have not been studied. We evaluate these considerations in the setting of energy services in the developing world, a contemporary development and sustainability imperative. We develop a database of relevant causal relations (313 concepts, 1337 relationships) asserted in the literature (561 peer-reviewed articles). We demonstrate that high-level relationships of interest to practitioners feature less consistent evidence than the causal relationships that underpin them, supporting increased use of problem decomposition through graphical modeling approaches. However, adding such detail increases complexity exponentially, introducing a hazard of overparameterization if evidence is not available to match the level of mechanistic detail. Published (Publication status)

In light of the consequences of global warming and population growth, access to safe drinking water becomes an ever greater challenge, in particular in low to middle income countries in arid regions. Moreover, mining which may cause acid mine drainage and heavy metal contamination puts further pressure on management of limited water resources. Hence, the development of cost effective water treatment methods is critical. Here, using batch reactor experiments we investigate the kinetics and mechanisms behind divalent Mn and trivalent Cr removal from sulfate fluids using natural fluorapatite at 35 °C. The results show that the fluorapatite dissolution rate depends on fluid pH, and that dissolution is the dominant mechanism in fluids with pH below 4. Apatite can thus serve as remediation to neutralize acidic fluids. Fluid pH of 4-6 triggers a dissolution-precipitation mechanism, in some cases following upon a dissolution-only period, with the formation of a metal phosphate. In these experiments, Cr removal is two to ten times faster than Mn removal given similar solution pH. The results demonstrate that natural apatite represents a promising, cost effective material for use in passive remediation of mining-induced contamination of soils and groundwater in arid regions. ispartof: JOURNAL OF HAZARDOUS MATERIALS vol:389 ispartof: location:Netherlands status: published

The surface-averaged forced Convective Heat Transfer Coefficient (CHTCavg) at a windward building facade is influenced by the complex interaction between a wide range of parameters. Existing CHTC expressions, however, consider the impact of these parameters either incompletely or not at all. Earlier studies have shown that this shortcoming can lead to significant errors in Building Energy Simulations. In this paper, therefore, the combined impacts of wind speed (U10), building height (H) and width (W), and wind direction (θ) on the CHTCavg for the windward facade of buildings are systematically investigated. High-resolution CFD simulations of wind flow and forced convective heat transfer, validated with wind-tunnel measurements, are performed for 64 building geometries (10 m ≤ H and W ≤ 80 m), 8 wind directions (0° ≤ θ ≤ 78.75°) and 4 reference wind speeds (1 m/s ≤ U10 ≤ 4 m/s). The 3D steady RANS equations with the realizable k-ε turbulence model and the low-Re number Wolfshtein model are used. The results show that for a given building geometry and U10, the CHTCavg decreases as θ increases from 0° to 78.75°. The maximum reduction of about 42% occurs for the building with H = 8W = 80 m. In addition, for a given θ and U10, by increasing H, the CHTCavg increases, while increasing W has the opposite impact on the CHTCavg. Finally, a new generalized CHTC expression is presented as a function of U10, H, W and θ and its accuracy is confirmed by detailed in-sample and out-of-sample evaluations.

Many complexities arise when applying conventional water treatment processes to small and remote systems. A significant challenge is the difficulty and impracticality of supplying chemicals needed for oxidation processes. A burgeoning, yet currently under-utilised, type of treatment are electrochemical technologies, which are receiving considerable research attention and innovation at present. In particular, through the advancement of high oxygen overpotential electrodes, the ability to synthesise highly oxidative chemical species under circumneutral pH conditions has become possible. In this study, the generation of highly oxidative iron-based species, specifically ferrate (Fe6+), has been explored utilising a boron-doped diamond (BDD) electrode and low concentrations of Fe2+ typically found in raw water, thereby eliminating the chemical supply chain required for conventional oxidation processes. Electrochemical ferrate generation experiments were performed in a batch-recycle configuration and were found to be mass transfer limited, whereby the rate-limiting step was the diffusion of Fe2+ to the electrode surface. This was evidenced by very little variation in ferrate generation at the three current densities tested, specifically 3.1 ± 0.2, 2.6 ± 0.2 and 3.3 ± 0.2 μM were generated at 10, 40 and 80 mA/cm2, respectively. Measured Fe6+ concentrations correlated well with those predicted by a mathematical process model, which assumed a completely mass transport limited process. While cyclic voltammetry confirmed ferrate generation by direct oxidation at the BDD surface, the contribution of hydroxyl radicals was indicated by the presence and absence of methanol, an OH scavenger, with ferrate generation decreased by greater than 50 % with methanol, compared to non-scavenged experiments. The results provide one of the first quantitative studies regarding the oxidation mechanisms of ferrate generation by electro-oxidation, and the first example of ferrate generation at circumneutral pH from Fe2+ at levels representative of raw water.

This paper investigates the parameters that influence the selective adsorption of phenol, toxic molecule, from a semi-model biofuel mixture containing alkanes and different proportions of aromatic compounds. The adsorption capacity, selectivity and regeneration ability of different adsorbents, i.e. zeolites, silica-based solids, alumina and activated carbon, were related to their textural properties and the nature, strength or location of their acidic sites. This work demonstrates that phenol differently adsorbs in the micropores and mesopores. In the micropores of faujasites, phenol is condensed into the supercages. Otherwise, in the mesopores of the zeolite, phenol interacts with the silanol groups. On purely siliceous adsorbents, a ratio of one phenol adsorbed on one silanol group could be established. As for selectivity, the strong acidic sites of the faujasites are necessary to favor phenol adsorption compared to toluene. By contrast, the amount of strong Brønsted and Lewis acid sites limits regeneration. Hence, a compromise has to be found and the best performances were obtained using a slightly dealuminated zeolitic adsorbent presenting both micro and mesopores. ispartof: Journal of Hazardous Materials vol:384 ispartof: location:Netherlands status: published

Private sustainability standards are spreading rapidly in global value chains, especially in the coffee sector, and commonly aim at promoting environmental, economic and social sustainability. The social sustainability component is often overlooked in studies on the impact of private standards. In this paper, we investigate a particular social outcome and analyse how adoption of private sustainability standards affects the welfare of children in coffee-producing farm-households in Ethiopia and Uganda. We specifically analyse school enrolment and schooling efficiency of primary and secondary school-aged children. We find that participation in Fairtrade certification schemes increases the likelihood of children to be enrolled in secondary school and improves their schooling efficiency, although it is not associated with higher incomes nor with a reduced child labour time in the farm-household. We find that participation in Rainforest Alliance certification schemes has no effect on schooling outcomes of boys and slightly reduces the schooling of girls, while it does correlate with higher incomes and a reduced workload of children. Results suggest that effects on schooling emerge through social capital and awareness-raising about the importance of schooling among Fairtrade certified households, rather than from the mere prohibition of child labour and the enforcement of a child-labour-free production process.

It is recognised worldwide that air pollution is the cause of premature deaths daily, thus necessitating the development of more reliable and accurate numerical tools. The present study implements a three dimensional Variational (3DVar) data assimilation (DA) approach to reduce the discrepancy between predicted pollution concentrations based on Computational Fluid Dynamics (CFD) with the ones measured in a wind tunnel experiment. The methodology is implemented on a wind tunnel test case which represents a localised neighbourhood environment. The improved accuracy of the CFD simulation using DA is discussed in terms of absolute error, mean squared error and scatter plots for the pollution concentration. It is shown that the difference between CFD results and wind tunnel data, computed by the mean squared error, can be reduced by up to three order of magnitudes when using DA. This reduction in error is preserved in the CFD results and its benefit can be seen through several time steps after re-running the CFD simulation. Subsequently an optimal sensors positioning is proposed. There is a trade-off between the accuracy and the number of sensors. It was found that the accuracy was improved when placing/considering the sensors which were near the pollution source or in regions where pollution concentrations were high. This demonstrated that only 14% of the wind tunnel data was needed, reducing the mean squared error by one order of magnitude.

Energy systems are currently designed focusing only on minimizing their cost or, at most, including limits on greenhouse gas emissions. Unfortunately, electricity technologies performing well in global warming potential might not necessarily behave equally well across other sustainability criteria. Hence, policies focused solely on mitigating greenhouse gas emissions could potentially resolve one problem (i.e., climate change) by creating another, thereby leading to burden-shifting. Here, the occurrence and severity of burden-shifting in energy systems design are both investigated through the application of a novel approach integrating multi-objective optimization, life cycle assessment and multivariate regression based on elasticities. Environmental impacts are classified into three categories: no burden-shifting, total burden-shifting and partial burden-shifting, providing for the latter two a measure of their severity. Due to inherent trade-offs in the life cycle performance of technologies, discussed in detail in this work, the Paris Agreement 2 °C targets would lead to burden-shifting in the United States (total or partial) in up to eight environmental impacts. On the other hand, stringent carbon emissions reductions in line with the 1.5 °C targets can lead to burden-shifting in three environmental impacts. Indeed, in both cases undesirable increases in some damage categories of up to 1.64% for every percentage increase in cost can take place as a result of more stringent limits on greenhouse gas emissions compared to the least cost solution. Overall, this work aims to foster fruitful discussions on how to generate energy within the Earth's ecological capacity by expanding the analysis beyond climate change.

In this article, the exp ( - Φ ( ξ ) ) -expansion method is modified for (3+1)-dimensional space–time coordinate system and successfully implemented to construct the new exact traveling wave solutions of the (3+1)-dimensional coupled Klein–Gordon–Zakharov equation. The solutions of this equation are expressed in terms of hyperbolic, trigonometric, exponential and rational functions. The results illustrate its effectiveness for solving nonlinear coupled partial differential equations arises in mathematical physics and engineering. The annihilation phenomena of the wave propagation in the x – y plane are also investigated. Furthermore, the three-dimensional surface plots due to the obtained solutions are also given to make the dynamics of the equation visible.

After fabric relaxation, there is a reduction in wale and course density due to a reduction in loop length and this actually will affect the fabric properties. Then, it is useful to find a relation between loop length and courses and wales per unit length as well as the yarn thickness because wales and courses per unit length can be easily measured at any state while it is difficult to measure the loop length in the knitted fabrics. Therefore, it is required to find an equation, through which the value of loop length can be easily calculated from the measured values of courses and wales per unit length at any state after the knitting process. In this work estimated equations to calculate the knitted loop length for open to normal structure and for normal to compact structure are developed. By comparing the value of the loop length predicted from this work with the other mentioned models, it was found that the calculated values are very near to the L value of the case study; so the developed equations are acceptable. The tightness factor and the porosity of single jersey fabrics were also calculated theoretically.

Concept of fractional order calculus is as old as the regular calculus. With the advent of high speed and cost effective computing power, now it is possible to model the real world control and signal processing problems using fractional order calculus. For the past two decades, applications of fractional order calculus, in system modeling, control and signal processing, have grown rapidly. This paper presents a systematic procedure for hardware implementation of the basic operators of fractional calculus i.e. fractional integrator and derivative, using Grunwald–Letnikov definition, on field programmable gate array (FPGA) in LabVIEW environment. The simulation and hardware implementation results for fractional order integrator and derivative of sinusoid and square waveform signals for some selected fractional orders have been presented. A close agreement between the simulated and the experimental results demonstrated the suitability of FPGA device in fractional order control and signal processing applications. LabVIEW being one of the finest tools for measurement and control, and signal processing applications the fractional order operator implementation is expected to further enhance the capability of the tool to cater to the needs of advanced experimental research employing fractional order operators.

Removal of the cationic dyes rhodamine B (RhB) and methylene blue (MB) by waste seeds Aleurites moluccana (WAM) was studied in a batch system. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), point of zero charge measurement, and the Boehm titration method. The effects of contact time and pH were investigated for the removal of cationic dyes. An increase in pH from 3 to 9 was accompanied by an approximately three-fold increase in the amount of dye adsorbed. The adsorptions equilibrium values were obtained and analyzed using the Langmuir, Freundlich, Sips, and Redlich–Peterson equations, the Sips isotherm being the one that showed the best correlation with the experimental values. The maximum adsorption capacities of the dyes were 178 mg/g for the MB and 117 mg/g for the RhB. The kinetic sorption was evaluated by the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, where it was observed that sorption follows the pseudo-second-order kinetic model. The study of thermodynamics showed that the adsorption is a spontaneous and endothermic process. The results indicate that waste seeds of A. moluccana could be used as a low cost material for the removal of cationic dyes from wastewater.

This work is focussed on the numerical modeling of mixed convection heat transfer effects in a lid-driven cavity filled with a copper–water nanofluid. A heated wall mounted block with constant heat flux is attached along the vertical wall. The left vertical wall is maintained at higher temperature compared to the right vertical wall and the other (top and bottom) walls are insulated. A finite volume based numerical approach with QUICK scheme is used for the solution of nonlinear governing equations. A computational visualization technique is used to represent the two dimensional results of streamlines, isotherms, average Nusselt number and bulk-average temperature for a wide range of physical parameters, namely Reynolds number, Rayleigh number and solid volume fraction. The effective fluid flow and heat transfer variation are analyzed by placing the heated mounted block first along the left vertical wall (Case-I) and then along the right vertical wall (Case-II) to test the maximum heat transfer effects. The changes in main characteristics of the flow due to variation of Reynolds number and Rayleigh number are elaborated. The effect of various flow parameters on the thermal conductivity behavior for both cases is discussed based on average Nusselt number and bulk-average temperature and found that Case-I shows higher heat transfer rate compared to Case-II, for higher Re , Ra and ϕ .

The ever growing human population and the corresponding economic development of mankind have caused a relentless surge in the energy demand of the world. The fast diminishing fossil fuel reserves and the overdependence of petroleum based fuels have already prompted the world to look for alternate sources of energy to offset the fuel crisis in the future. Waste Cooking Oil Methyl Ester (WCOME) has proven itself as a viable alternate fuel that can be used in Compression Ignition (CI) engines due to its low cost, non-toxicity, biodegradability and renewable nature. It also contributes a minimum amount of net greenhouse gases, such as CO 2 , SO 2 and NO emissions to the atmosphere. The main objective of this paper is to focus on the study of the performance, combustion and emission parameters of CI engines using WCOME and to explore the possibility of utilizing WCOME blends with diesel extensively in place of diesel. The production methods used for transesterification play a vital role in the physiochemical properties of the methyl esters produced. Various production intensification technologies such as hydrodynamic cavitation and ultrasonic cavitation were employed to improve the yield of the methyl esters during transesterification. This review includes the study of WCOME from different origins in various types of diesel engines. Most of the studies comply with the decrease in carbon monoxide (CO) emissions and the increase in brake thermal efficiency while using WCOME in CI engines. Many researchers reported slight increase in the emissions of oxides of nitrogen. ANN modeling has been widely used to predict the process variables of the diesel engine while using WCOME. The versatility of ANN modeling was proven by the minimum error percentages of the actual and predicted values of the performance and emission characteristics.

Economic Load Dispatch (ELD) is the process of allocating the required load between the available generation units such that the cost of operation is minimized. The ELD problem is formulated as a nonlinear constrained optimization problem with both equality and inequality constraints. The dual-objective Combined Economic Emission Dispatch (CEED) problem is considering the environmental impacts that accumulated from emission of gaseous pollutants of fossil-fuelled power plants. In this paper, an implementation of Flower Pollination Algorithm (FPA) to solve ELD and CEED problems in power systems is discussed. Results obtained by the proposed FPA are compared with other optimization algorithms for various power systems. The results introduced in this paper show that the proposed FPA outlasts other techniques even for large scale power system considering valve point effect in terms of total cost and computational time.

Hall effects on an unsteady magnetohydrodynamic (MHD) free convective flow of a viscous incompressible electrically conducting optically thick radiating fluid past a vertical porous plate in the presence of a uniform transverse magnetic field are examined. The governing equations are solved numerically using the fourth-order Runge–Kutta–Fehlberg method with the shooting technique. Effects of the pertinent parameters on the flow field, temperature distribution, shear stresses and rate of heat transfer at the plate are presented in graphs and tables followed by a quantitative discussion. The results reveal that the flow field and the temperature distribution are greatly influenced by thermal radiation parameter. Hall currents moderate the flow field significantly. Suction (or injection) has a profound effect on the boundary layer thickness in which the suction reduces the thermal boundary layer thickness whereas injection thickens it.

Wire electrical discharge machining (EDM) possesses many advantages over the conventional manufacturing process. Hence, this process was used for machining of all conductive materials; especially, nowadays this is the most common process for machining of aerospace aluminum alloys. This process produces complex shapes in aluminum alloys with extremely tight tolerances in a single setup. But, for good surface integrity and longer service life, the residual stresses generated on the components should be as low as possible and it depends on the setting of process parameters and the material to be machined. In wire EDM, much of the work was concentrated on Titanium alloys, Inconel alloys and various types of steels and partly on aluminum alloys. The present investigation was a parametric analysis of wire EDM parameters on residual stresses in the machining of aluminum alloy using Taguchi method. The results obtained had shown a wide range of residual stresses from 8.2 to 405.6 MPa. It also influenced the formation of various intermetallics such as AlCu and AlCu3. Microscopic examination revealed absence of surface cracks on aluminum surface at all the machining conditions. Here, an attempt was made to compare the results of aluminum alloy with the available machined data for other metals.

Project scheduling is an important part of construction project planning. Resource leveling is the process used within project scheduling to reduce fluctuations in resource usage over the period of project implementation. These fluctuations frequently create the untenable requirement of regularly hiring and firing temporary staff resources to meet short-term project needs. Construction project decision makers currently rely on experience-based methods to manage fluctuations. However, these methods lack consistency and may result in unnecessary wastage of resources or costly schedule overruns. This research introduces a novel optimization model called the Fuzzy Clustering Chaotic-based Differential Evolution for solving multiple resources leveling in the multiple projects scheduling problem (FCDE-MRLMP). The novel Fuzzy Clustering Chaotic-based Differential Evolution (FCDE) algorithm integrates fuzzy c-means clustering and chaotic techniques into the original Differential Evolution (DE) algorithm to handle complex optimization problems. The chaotic technique prevents the optimization algorithm from converging prematurely. The fuzzy c-means clustering technique acts as several multi-parent crossover operators in order to utilize population information efficiently and enhance convergence efficiency. Experiments run indicate that the proposed model obtains optimal results more reliably and efficiently than the benchmark algorithms considered. The proposed optimization model is a promising alternative approach to assist project managers to handle resource-leveling project scheduling problems effectively.

In this paper, a solar liquid desiccant air conditioning (SLDAC) system has been studied. The effect of changing evacuated tube collector area on the performance of the SLDAC system was fulfillment. This inquest was done over all a year in Borg Al-Arab city located in the Northern region of Egypt. Meteorological data, such as hourly average solar radiations and temperatures, were needed to achieve this research. The hourly cooling loads were determined by using Hourly Analysis Program (HAP) 4.7. These loads are wall, illumination, people, and equipment loads. Then, the hourly differences of different parameters such as amount of water absorbed in conditioner, amount of water desorbed in regenerator, hot water temperature and coefficient of the performance were calculated. In addition, the maximum solar thermal energy was determined to meet the regeneration demand according to the hourly average solar radiation data. For 220 m 2 evacuated tube collector area, the maximum required heat energy is obtained as 38,286 kW h on December, while using solar energy, will save energy by 30.28% annual value.

A systematic investigation of the influence of particle coverage on the dynamics of rising bubbles was carried out using high-speed photography and image analysis techniques to study bubble behavior in terms of changes in velocity and aspect ratio. The buoyancy force and drag force exerted on the bubbles and the effect of particles were calculated to further understand their behavior. Results show that particles attached on the bubbles strongly dampen the oscillations observed in bubble aspect ratio and decrease its velocity and acceleration. The particles also render the bubbles more spherical and slow their velocity. It was found that the overall velocity of a bubble is directly correlated to its aspect ratio and inversely correlated to its particle coverage, while the acceleration and the aspect ratio and its change are inversely correlated. Interestingly, the trend observed in the oscillation and the oscillation period of particle-laden bubbles is similar for different levels of particle coating. A drag modification factor eta(p), which quantifies the drag influence of particles on bubble velocity, was identified from force analysis. A modified drag coefficient for uncoated and particle-laden bubbles was introduced, which allows, for the first time, to predict the behavior of rising bubbles in gas-liquid-particle systems.