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Highlights: [•] Chance constrained optimization model developed to evaluate biodiesel blends. [•] Physical property derivation of technical constraints derived from fatty acid types. [•] Uncertainty and variation in feedstocks managed through optimization formulation. [•] Feedstock diversification reduces costs while maintaining fuel specifications. [ABSTRACT FROM AUTHOR]

Abstract: Membranes possessing both fouling resistance and permeate size cut-offs in the nanometer range would open membrane processes to numerous molecular separations in the biochemical, pharmaceutical and food industries. This study describes the preparation of novel thin film composite (TFC) nanofiltration (NF) membranes with the above properties, where the selective layer is a dense coating of the amphiphilic comb copolymer polyacrylonitrile-graft-poly(ethylene oxide) (PAN-g-PEO). PAN-g-PEO is synthesized by free-radical polymerization using a macromonomer method, and solution coated onto a PAN ultrafiltration (UF) membrane support. Upon coagulation of the coating, microphase separation occurs between the hydrophobic PAN backbone and hydrophilic PEO side chains, as determined by differential scanning calorimetry (DSC). Transmission electron microscopy (TEM) reveals the formation of an interconnected network of PEO domains that act as water-permeable nanochannels and provide the size-based separation capability of the membrane. In filtration studies, the pure water permeability of PAN-g-PEO TFC NF membranes was found to be 85±25L/m2 hMPa, over 4 times that of a commercial NF membrane control. The permeate size cut-off was determined by the filtration of a series of rigid dye molecules to be less than 1nm, and the fractionation of a mixture of two anionic dyes, Congo Red and Ethyl Orange, was demonstrated. Further, the membrane showed complete resistance to fouling, defined as flux loss that cannot be recovered by a water rinse, by 1g/L bovine serum albumin (BSA) in a 24-hour dead-end filtration experiment, demonstrating the promise of these membranes for biomolecule separations. [Copyright &y& Elsevier]

Abstract Decision-makers in government and industry must develop policy and strategy for highly complex systems, trading off competing objectives such as environmental and economic impact. These trade-offs can be difficult to analyze, which may lead to misinformed choices. There is lack of decision support tools that both include multiple objectives and facilitate communication to decision-makers in a comprehensive and simple way. To address this gap, a mathematical model that facilitates the decision process by allowing an agent to decide based on an explicit overall economic and environmental performance but simultaneously visualize graphically the trade-offs among the different objectives was developed. This model was used to assess the trade-offs of using waste-based feedstocks in blends with conventional feedstocks for biodiesel production, and explore opportunities to improve biodiesel cost effectiveness whilst managing environmental impacts, particularly in the feedstock selection process. The compositional uncertainty of the feedstocks is considered in the model ensuring that the final quality of the biodiesel is not compromised by the high uncertainty associated with the composition of waste materials. Reductions on production costs (3%) and on environmental impacts (from 2% to 32%) were obtained using this model to select the blend composition. The model was shown to be useful to inform decision-making by allowing comprehensive, simplified visualization of the trade-offs among cost and environmental impacts. The model can be used to support biodiesel production planning with lower environmental impacts. Highlights • Blends for biodiesel production using waste-based feedstocks are optimized. • Trade-offs between cost and environmental impacts are analyzed. • Compositional uncertainty of the feedstocks is addressed. • Blends optimization allows a reduction in cost and environmental impacts. • The model allows a simplified visualization of the trade-offs among the objectives. [ABSTRACT FROM AUTHOR]

Biodiesel is globally produced by transesterification of vegetable oils. Each vegetable oil possesses a typical fatty acid (FA) profile that will influence the final properties of the biodiesel. Models have been developed to express the relationship between the FA composition and the fuel properties. However, as the FA sources are variable and because the chemical composition of a FA source are not always fully characterized, this variability translates into uncertainty for the production planner. This paper explores the underlying variability associated with the FA composition and assesses the results of these models incorporating FA compositional uncertainty. Models for viscosity, density, cetane number, iodine value, cold filter plugging point and oxidative stability were considered. The potential range of properties given by the models was compared with values reported in the literature. The main goal is to assess the influence of compositional uncertainty and the potential existence of systematic deviations in the results provided by these models. This assessment can be used to improve production plans with tools that account for compositional uncertainty and variability, allowing the biodiesel producer planner to determine blends that minimize the risk of noncompliance with the technical requirements. [ABSTRACT FROM AUTHOR]

Redox flow batteries (RFBs) are a promising electrochemical storage solution for power sector decarbonization, particularly emerging long-duration needs. While the battery architecture can host many different redox chemistries, the vanadium RFB (VRFB) represents the current state-of-the-art due to its favorable combination of performance and longevity. However, the relatively high and volatile price of vanadium has hindered VRFB financing and deployment opportunities. Here we evaluate the vanadium supply chain to understand how it enables or constrains VRFB advancement and assess opportunities for accelerated growth. We find that – while vanadium may not be scarce – its abundance is confounded by highly concentrated production coupled with the disperse nature of sources suitable for potential supply increase. These factors challenge rapid growth, limiting deployment rate and magnitude. We estimate gigawatt-hour deployment scales are feasible over the next decade, which would represent marked expansion of the RFB industry and drive down system costs substantially, though this would require growth rates to vanadium production above historical averages. Accordingly, we review opportunities to accelerate supply chain growth and economic strategies to stabilize the market. Finally, we posit terawatt-hour deployment scales will be challenged by vanadium market conditions and resource availability, motivating the continued efforts developing next-generation RFB chemistries. • Vanadium flow batteries show technical promise for decarbonizing the power sector. • High and volatile vanadium prices limit deployment of vanadium flow batteries. • Vanadium is globally abundant but in low grades, hindering economic extraction. • Vanadium's supply is highly concentrated as co-/by-product production. • Opportunities for growth of vanadium supply lie in principal and secondary streams. [ABSTRACT FROM AUTHOR]

Abstract: What is the burden upon your feet? With sales of running and jogging shoes in the world averaging a nontrivial 25 billion shoes per year, or 34 million per day, the impact of the footwear industry represents a significant portion of the apparel sector''s environmental burden. A single shoe can contain 65 discrete parts that require 360 processing steps for assembly. While brand name companies dictate product design and material specifications, the actual manufacturing of footwear is typically contracted to manufacturers based in emerging economies. Using life cycle assessment methodology in accordance with the ISO 14040/14044 standards, this effort quantifies the life cycle greenhouse gas emissions, often referred to as a carbon footprint, of a pair of running shoes. Furthermore, mitigation strategies are proposed focusing on high leverage aspects of the life cycle. Using this approach, it is estimated that the carbon footprint of a typical pair of running shoes made of synthetic materials is 14 ± 2.7 kg CO2-equivalent. The vast majority of this impact is incurred during the materials processing and manufacturing stages, which make up around 29% and 68% of the total impact, respectively. Other similar studies in the apparel industry have reported carbon footprints of running shoes ranging between 18 and 41 kg CO2-equivalent/pair (PUMA, 2008; Timberland, 2009). For consumer products not requiring electricity during use, the intensity of emissions in the manufacturing phase is atypical; most commonly, materials make up the biggest percentage of impact. This distinction highlights the importance of identifying mitigation strategies within the manufacturing process, and the need to evaluate the emissions reduction efficacy of each potential strategy. By suggesting a few of the causes of manufacturing dominance in the global warming potential assessment of this product, this study hypothesizes the characteristics of a product that could lead to high manufacturing impact. Some of these characteristics include the source of energy in manufacturing and the form of manufacturing, in other words the complexity of processes used and the area over which these process are performed (particularly when a product involves numerous parts and light materials). Thereby, the work provides an example when relying solely on the bill of materials information for product greenhouse gas emissions assessment may underestimate life cycle burden and ignore potentially high impact mitigation strategies. [Copyright &y& Elsevier]

A methodology for calibrating pH meters in highly alkaline solutions such as those relevant to cementitious systems is presented. This methodology uses an extended form of the Debye-Hückel equation to generate a calibration curve of pH vs. the measured electrochemical potential (mV) based on a series of aqueous alkali hydroxide solutions of known concentrations. This methodology is compared with the 'built-in' process of calibration based upon pH 4, 7, and 10 standard solutions. The built-in calibration process underestimates the real pH values by up to 0.3 log units, which is attributed to the alkali error. A spreadsheet for determining the calibration curve and its application to pH meter readings is provided as Supporting Information. The implications of improperly calibrated pH meters on interpreting solution chemistry in cementitious systems are discussed. [ABSTRACT FROM AUTHOR]

Here, we present a computational framework, combining machine learning models with inverse optimization, which can accelerate and optimize concrete mix design with respect to climate impact and/or cost. Our approach leverages a novel amortized Gaussian process (GP) model trained on a large industry dataset to predict concrete strength based on mix proportions. The resulting GP model has an R 2 value, RMSE, and MAPE of ∼0.88, ∼909 psi (6.3 MPa), and ∼10.8 %, respectively. We integrated the GP model with an inverse optimization scheme to predict optimal mix designs that minimize cost and/or climate impact. The results show that this integrated framework can generate reasonable concrete mixes that offer up to ∼30 % and ∼60 % reductions in cost and climate impact, respectively, compared with industry mixes with similar 28-day strength. This study highlights the potential environmental and economic benefits of data-driven approaches to designing and optimizing concrete mixes. [ABSTRACT FROM AUTHOR]

Recycling is generally recognized as a key component of strategies to achieve improved resource efficiency and reduce the environmental burden associated with resource use. However, to maximize the net benefits offered by recycling, one must understand the system-wide effects of substituting primary materials with recycled materials and how those effects vary under alternative strategies. Consequential life cycle assessment (cLCA) approaches to evaluate the impact of increasing use of recycled materials require identification of grades and sources of scrap materials used at the margin. Various grades of recycled materials differ in their substitution possibilities and supply limits. However, most studies of cLCA for material recycling overlook these aspects and typically assume a fixed set of marginal activities. This study develops a model to describe the resource consumption behaviors of material producers and the resulting cascade of material flows for the case of the United States (US) pulp and paper industry. We observe that grades and sources of scrap materials used at the margin dynamically change so as the resulting environmental impact when demand for recycled containerboard products increases. The results show that the greenhouse gas (GHG) emission savings effect of using recycled materials can be considerably larger when marginal recovered fiber comes from additional recovery from landfill rather than being diverted from the export market. Also, the results show that the behavior of international trade partners for recovered paper may offset GHG emission savings from the domestic replacement of virgin pulpwood with recovered paper. Most importantly, such behaviors are dependent on grades used at the margin. The developed model and results can help inform the US pulp and paper industry, policymakers, and other stakeholders about the system-wide effects of increasing use of recovered paper. • We develop a model to describe resource consumption behaviors of the US pulp and paper producers and resulting fiber flows. • This study suggests the importance of identifying the grade and source of scrap used at the margin in the recycling industry. • CLCA based on static marginal technologies may not correctly quantify the system-wide effect of material recycling. [ABSTRACT FROM AUTHOR]

Biomass ash results from the combustion of agricultural residues, which, in many developing countries, are a primary source of power generation for small and medium size industries. This study focuses on the performance of a binder synthesized from an Indian biomass ash, Indo-Gangetic clay, hydrated lime, and aqueous 1M NaOH solution. To measure the extent of leaching and its impact on physicochemical properties, the biomass ash binder in powder form (<45 μm size) was exposed to two different leaching media: deionized water and 0.1M HNO 3 at two different solution-to-sample ratios (by wt.) of 10 and 100. Sodium leaching was found to be prominent in the biomass ash binder irrespective of leaching medium and solution-to-sample ratio. However, calcium leaching was significantly higher in 0.1M HNO 3 than in deionized water. Calcium silicate hydrate present in the biomass ash binder was found to be less chemically stable in 0.1M HNO 3 , exhibiting complete calcium leaching at a solution-to-sample ratio of 100. Furthermore, significant leaching of calcium in 0.1M HNO 3 solution resulted in phase modification of calcium silicate hydrate, the main reaction product of the biomass ash binder. [ABSTRACT FROM AUTHOR]

• Incomplete recovery of materials in mobile phones results in a significant economic loss. • We quantify the appreciable economic potential of non-PCB derived metals. • Preprocessors should focus on precious metals in fine shredding and develop strategies for plastics recycling. Incomplete recovery of materials in mobile phones results in a significant economic loss. Many studies have focused on improving the situation by characterizing metals within printed circuit boards (PCBs) to identify where losses occur. Our work focuses on the evolving composition of mobile phones and particularly the flow of materials located within components outside of PCBs. In this study we quantify the appreciable economic potential of non-PCB derived metals and provide suggestions for optimization of different preprocessing steps to recover these materials. These opportunities can be categorized as recovering both high value and high volume materials. We therefore recommend that preprocessors pay special attention to precious metals in fine shredding and develop strategies for plastics recycling based on our demand and supply forecasts of postconsumer plastics in phones. We have performed this work based on a case study of Portugal. [ABSTRACT FROM AUTHOR]

Life cycle assessments (LCAs) provide valuable guidance regarding environmental implications of design and manufacturing choice; however, they remain resource intensive and time consuming. Streamlining approaches have been developed to address these issues. One of these streamlining approaches, structured under-specification and probabilistic triage, develops a high level assessment of the product or service in question, and only obtains more data on those parameters that contribute most both to the uncertainty and the total impact. In this paper, we build upon the structured under-specification and probabilistic triage methodology and include metrics to determine when sufficient data has been collected. This method enables significant reduction in effort to conduct an LCA while still preserving the ability to make resolvable conclusions around environmental choice related to reducing the impact of manufacturing these devices. We demonstrate the efficiency and effectiveness of this methodology on a case study of tablets for which we determine the burden of the product with 30% of the total effort required in a traditional LCA approach, thereby more readily focusing efforts for impact mitigation. We find that the life cycle environmental impact of the product is driven by the materials and manufacturing phase, more specifically the manufacturing of electronic components such as integrated circuits and printed wiring boards. [ABSTRACT FROM AUTHOR]

Optimization of manufacturing processes and practices requires multiple tradeoffs among often competing priorities. This is especially the case for green manufacturing, where meeting sustainability goals often requires the use of more expensive materials and technologies with uncertain effects on product performance. Not only are decisions regarding such trade-offs difficult to make, these decisions often need to be made with incomplete and uncertain information. These scenarios often result in requests for more information, some of which may be irrelevant for the decision at hand. Value of information (VoI), a decision analytic method for quantifying the expected benefit of acquiring additional information, can be used to improve a wide range of manufacturing decisions. By identifying the contribution of specific model parameter uncertainty to total product or decision uncertainty, VoI can prioritize additional data collection and research strategies to optimally reduce uncertainty and support decisions, i.e., identifying the greatest “bang for the buck.” VoI has been used in many fields including medicine, ecology, and economics, but is rarely used in manufacturing and has never been applied within life cycle assessment (LCA), e.g., to address uncertainty in product development decisions. This paper discusses the use of VoI with LCA in manufacturing and details a case study in which we calculate VoI related to the lifecycle environmental impact of electronic tablet production. We found that LCA-VoI can be successfully used to triage the data gathering process in electronic tablets, to more accurately describe lifecycle environmental impact. We anticipate future applications of LCA-VoI to lead to more cost-effective and sustainable production. [ABSTRACT FROM AUTHOR]

While the incineration of biomass residues is gaining traction as a globally available source of renewable energy, the resulting ash is often landfilled, resulting in the disposal of what could otherwise be used in value-added products. This research focuses on the beneficial use of predominantly rice husk and sugarcane bagasse-based mixed biomass ashes, obtained from two paper mills in northern India. A cementitious binder was formulated from biomass ash, clay, and hydrated lime (70:20:10 by mass, respectively) using 2M NaOH solution at a liquid-to-solid mass ratio of 0.40. Compressive strength of the biomass ash binder increased linearly with compaction pressure, indicating the role of packing density. Between the two mixed biomass ashes used in this study, the one with higher amorphous content resulted in a binder with higher strength and denser reaction product. Multi-faceted characterization of the biomass ash binder indicated the presence of aluminum-substituted calcium silicate hydrate, mainly derived from the pozzolanic reaction. [ABSTRACT FROM AUTHOR]

Exciting metallurgical breakthroughs of the last decades alongside the development and wide-ranging availability of new and more capable experimental and theoretical tools for metals research demonstrate that we are witnessing the dawn of a new age in metals design. Historically, the discovery of new metallic materials has enabled the vast majority of the key engineering advances in human history. Current engineering challenges create an urgent need for new metallic materials to further our technological advances in multiple industries that are key to our existence. Yet, present data on metals processing clearly demonstrate the significant environmental impact of the metallurgical industry on our planet's future. There are numerous reports in which this impact and corresponding processing solutions are discussed. On the other hand, design of new metallic materials with improved property combinations can help address key environmental challenges in various ways. To this end, the goal of this review is to discuss the most urgent sustainability challenges that can be addressed with alloy design, to help orchestrate the increasing interest in metallurgical research to focus on these most critical challenges. [ABSTRACT FROM AUTHOR]

The link between manufacturing variability and the resulting environmental impact is an understudied topic. We connect manufacturing variability and greenhouse gas emissions impact through the reality of overdesign. Specifically, this study takes the case of manufacturing Carbon Fiber Reinforced Polymers, which has high manufacturing variability relative to conventional manufacturing processes and is of interest due to its light-weighting potential. Through the use of a process-based cost model, including uncertainty , the cost and energy required to fabricate a representative composite part is modeled. The model then connects to a fuel-consumption model of a Boeing 787 which allows the estimation of lifetime fuel savings. Manufacturing variability is taken as an input to the model, which allows the model to estimate the effect of variability on both the cost and energy requirements. We find that manufacturing variability has a significant impact on both part cost and energy requirements, being the fourth most impactful variable in our model for both these performance measures. Under our assumptions, reducing the coefficient of variation of the mechanical properties from 14% to 9% reduces production costs and energy by 12.3 and 11.8%, respectively. In addition, due to the weight savings, we estimate that over the lifetime of a Boeing 787 this drop in variability saves 8.3 kton of fuel, which has a present value of 3.6 million USD and would prevent 21.9 kton carbon dioxide from entering the atmosphere. [ABSTRACT FROM AUTHOR]

This study explores the effect of aqueous chemical environment on the dissolution rate of the minerals γ-C 2 S and fayalite, identified as primary phases of ladle furnace steel slag and copper slag. γ-C 2 S and fayalite were exposed to solutions of NaOH and Ca(OH) 2 , chosen to mimic the pore solutions of alkali-activated and Portland-cement based binders. While both from the olivine mineral group, γ-C 2 S and fayalite displayed opposing dissolution trends with respect to pH. The rates of γ-C 2 S dissolution were observed to decrease with higher pH, while fayalite dissolution rates increased with pH, and both relationships were described via empirical functions of the form R = k ∙ a H + n . The contrasting dependence of dissolution rate on pH for both minerals was attributed to the formation of chemically distinct surface layers on both minerals during dissolution. These results have significance for blending of slags with high olivine contents in binders with a range of aqueous chemical environments. [ABSTRACT FROM AUTHOR]

The environmental life cycle impact of electronics continues to be of interest within the life cycle arena. Previous work has shown the majority of burden can be attributed to the use phase as well as the manufacturing impact of components. This study leverages primary data from an industrial facility to provide an assessment of the cradle-to-gate global warming potential for printed wiring board (PWBs) components used in electronics equipment. There has not been as much evolution in the technology for PWBs as compared to other components such as integrated circuits. A newer technology, high-density interconnect (HDI) PWBs, is evaluated in addition to conventional boards based on various representative designs for consumer products. The results show that the board impact for handheld devices, notebooks and desktops range from to around 0.6 to 10 kgCO 2 e/board. The cradle-to-gate global warming potential is dominated by the manufacturing energy to fabricate the board as well as the board laminate materials (80% of the total impact). The study demonstrates that environmental impact varies by design parameters other than layer count and board area. The research also assesses the water use and chemical hazard associated with PWB manufacture. • We analyze global warming, water, and chemical use for printed wiring boards. • Variation of impact with design of high density interconnect boards. • Impact driven by energy to fabricate boards and board laminate materials. [ABSTRACT FROM AUTHOR]