An integrated optimization modeling approach for planning emission trading and clean-energy development under uncertainty

The growing concern for global warming caused by the increased atmospheric concentration of carbon dioxide (CO₂) has a significant effect on environmental and energy policies and economic activities, due to the ever-increasing use of fossil fuels such as coal, oil and natural gas throughout the world. A variety of complexities and uncertainties exist in CO₂-emission-related processes and various impact factors, such as CO₂-emission inventory, mitigation measure, and cost parameter. Decision makers face problems of how many clean-energy resources (or carbon credits) are needed to be replaced (or bought) by measuring electric-power benefits and uncertain economic penalties from random excess CO₂ exceeding to given discharge permits. In this study, an integrated optimization modeling approach is developed for planning CO₂ abatement through emission trading scheme (ETS) and clean development mechanism (CDM), where uncertainties presented in terms of fuzzy sets, interval values, and random variables can be addressed. The developed model is also applied to a case study of planning CO₂-emission mitigation for an electric-power system (EPS) that involves three fossil-fueled power plants (i.e., gas, oil and coal-power plants). Different trading schemes and clean-energy development plans corresponding to different CO₂-emission management policies have been analyzed. The results demonstrate that CO₂-emission reduction program can be performed cost-effective through emission trading and clean-energy development projects. Violation analyses are also conducted to demonstrate that different violation levels for model’s objective and constraints have different effects on system benefit and satisfaction degree as well as emission trading and clean-energy development.     

Residential energy efficiency retrofits: How program design affects participation and outcomes

Better methods of characterizing and addressing heterogeneity in preferences and decision making are needed to stimulate reductions in household greenhouse gas emissions. Four residential energy efficiency programs were delivered consecutively in the Region of Waterloo, Canada, between 1999 and 2011, and each offered a unique combination of information, financial reward structure, and price. A natural quasi-experimental intervention design was employed to assess differences in outcomes across these program structures. Participation at the initial (evaluation by an energy advisor) and follow-up (verification of retrofit) stages, and the material characteristics (e.g., energy performance) were measured and compared between the groups of houses included in each program at each stage. The programs appealed to people with different types of material concerns; each phase of the program was associated with houses with a different mix of material characteristics and depths of recommended and achieved changes. While a performance-based reward attracted fewer houses at each stage than a larger list-based reward, older houses with poorer energy performance were included at each stage. The findings support experimentation with program designs to target sub-populations of housing stock; future program designs should experiment more carefully and with larger performance-based rewards and test parallels with potential carbon market structures.     

Extracting compressive stress-strain curve based on stick-slip shear banding process in bulk metallic glasses

Based on the stick-slip process, an effective method to extract the stress-strain curve directly from the crosshead displacement-load raw data in compression of bulk metallic glasses was proposed.The method was tested in two bulk metallic glass samples with different plasticities and shear band morphologies.The extracted stress-strain curves were found to well resemble the stress-strain curve measured by a laser ex-tensometer.In addition, the extracted curve could resolve fine structures of serrated flow much better than that measured by extensometer, thus facilitating the study of shear banding process.Results obtained by this method made the stick-slip dynamics of shear banding valid, and this method could be employed to obtain the real strain of small-sized metallic glass samples where extensometer cannot be applied.     

Designing and constructing networks under uncertainty in the construction stage: Definition and exact algorithmic approach

The present work proposes a novel Network Optimization problem whose core is to combine both network design and network construction scheduling under uncertainty into a single two-stage robust optimization model. The first-stage decisions correspond to those of a classical network design problem, while the second-stage decisions correspond to those of a network construction scheduling problem (NCS) under uncertainty. The resulting problem, which we will refer to as the Two-Stage Robust Network Design and Construction Problem (2SRNDC), aims at providing a modeling framework in which the design decision not only depends on the design costs (e.g., distances) but also on the corresponding construction plan (e.g., time to provide service to costumers). We provide motivations, mixed integer programming formulations, and an exact algorithm for the 2SRNDC. Experimental results on a large set of instances show the effectiveness of the model in providing robust solutions, and the capability of the proposed algorithm to provide good solutions in reasonable running times.     

The role of price as a product attribute in the organic food context: An exploration based on actual purchase data

High prices are often quoted as an obstacle to consumer purchase of organic food products. This article investigates the market performance of organic food products at different price levels and whether high price is necessarily a disadvantage for organic food products, especially with regard to generating repeat purchase. Based on analyses of panel purchase data from 2011 in Denmark, the study explores the effects of production method (organic vs. conventional) and price on consumers’ repeat purchase and cross-purchase across four product categories: red meat, chicken, milk and hard cheese. Results show that a high price is a disadvantage for generating repeat purchase of organic food products. Although organic products enjoy higher repeat purchase than conventional products overall, a high price generates less repeat purchase of organic products than a low or a medium price in all product categories; whereas in the case of conventional food products the situation is the reverse. At the same time, the cross-purchase analysis reveals that consumers who buy organic products from the high price tier are less likely to switch to other price tiers than consumers who buy low or medium price organic products (i.e. there is a spillover of high price organic food purchases to other product categories). Implications for pricing strategies for organic food products are discussed.     

Relationship between pungency and food components – A comparison of chemical and sensory evaluations

The influence of food ingredients (water, starch, fat, and sugar), individually and in combination, on the sensory perception of the pungency of capsaicin was studied in model food systems using the time-intensity method. Furthermore, the transferability of the results obtained using model food matrices to complex matrices, such as convenience salsas, was investigated. Significant differences between the samples (p < 0.05) were examined by analysis of variance (ANOVA) followed by the Tukey-HSD post hoc test. A highly complex matrix and a high starch content reduced the perception of pungency in both the model food matrices and the convenience salsa products. Therefore, the time-related maximum intensity of pungency (I_max) was affected by other factors in addition to the capsaicin concentration.The total capsaicinoid content in the salsas was quantified by high-performance liquid chromatography–mass spectrometry (HPLC–MS) and correlated to the results of the sensory evaluation. The best correlation (R² = 0.8029) was observed for the total capsaicinoid content and the maximum intensity of pungency (I_max) in comparison to the duration of the total pungency perception T_Dur (R² = 0.5176) and the area under the curve (R² = 0.6898). The calculated regression models serve as an example of how empirical calculations can be generated and used in a specific context.     

Controlled transglutaminase treatment in Edam cheese-making

Transglutaminase (TG) has been widely used in the dairy industry to increase product yield. However, it has not been used in the production of ripened cheeses because of the difficulty of controlling TG activity. It was observed that cross-linking of TG in ultrafiltration retentate could be controlled using a protein standardisation step. TG increased the cheese yield 4%, due to an increase in the moisture content of the cheeses. Traditionally, increased cheese moisture reduces hardness of cheese, but this was not observed in the cheese from TG-treated milk. Furthermore, the organoleptic properties of the TG-cheeses did not differ significantly from those of the control cheeses. No differences were observed in the protein profile of the whey fraction as a result of the TG treatment. The protein standardisation process thus makes it possible to use TG in the production of Edam cheese.     

The triangle assessment method: A new procedure for eliciting expert judgement

The Analytic Hierarchy Process (AHP) is one of the most widely used Multi-Criteria Decision-Making methods worldwide. As such, it is subject to criticisms that highlight some potential weaknesses. In this study, we present a new Multi-Criteria Decision-Making method denominated the “Triangular Assessment Method” (referred to by its Spanish abbreviation, MTC^©). The MTC^© aims to make use of the potential of AHP while avoiding some of its drawbacks. The main characteristics and advantages of the MTC^© can be summarised as follows: (i) evaluation of criteria, and of the alternative options for each criterion, in trios instead of pairs; (ii) elimination of discrete scales and values involved in judgements; (iii) a substantial reduction in the number of evaluations (trios) relative to the corresponding number of pairs which would have to be considered when applying the AHP method; (iv) consistent decision-making; (v) introduction of closed cyclical series for comparing criteria and alternatives; and (vi) the introduction of opinion vectors and opinion surfaces. This new method is recommended for supporting decision-making with large numbers of subjective criteria and/or alternatives and also for group decisions where the consensus must be evaluated. The MTC^© provides a different promising perspective in decision-making and could lead to new research lines in the field of information systems.     

Frother function–structure relationship: Dependence of CCC95 on HLB and the H-ratio

Although the number and diversity of commercial frothers has steadily increased to meet flotation industry demands, frother selection is still mainly empirical. As part of a general structure–property study, the paper presents a correlation between the critical coalescence concentration (CCC95) and H-ratio for surfactants used as flotation frothers. The CCC95 were determined in 0.8 m³ mechanical flotation cell. The H-ratio was a substitution of hydrophile-lipophile balance (HLB) and determined through high resolution proton nuclear magnetic resonance (¹H NMR) spectrometry. A large data set, consisting of 45 surfactants from four frother families, was used to develop the correlation. It is shown that the H-ratio can substitute for HLB. The potential of NMR both to identify the frother family and to derive the H-ratio in predicting CCC95 for commercial frothers is discussed.