•Systematic review of 33 studies of cement and concrete decarbonization strategies.•A consensus exists on technological measures for decarbonization, but not policies.•Future studies should link ...barriers to specific policy actions to overcome them.•Policy actions should have clear distinctions between goals and mechanisms.
The production and use of cement, the binding agent in concrete, emits seven percent of global greenhouse gas emissions annually. Achieving climate change mitigation targets, such as those proposed in the Paris Agreement, requires emission reductions from this sector. The body of research on technical solutions to cement and concrete decarbonization is wide, but technical measures must be coupled with effective policy to achieve decarbonization. This study undertakes a review of previous research on cement and concrete decarbonization and analyzes the most common proposed measures along their level of action, involved stakeholders, barriers to implementation, and coordinated policy actions.
The review yielded 37 studies from peer-reviewed articles and technical reports. Analysis showed consensus on the primary technical measures to decarbonize. For cement production, measures include (I) improved energy efficiency, (II) fuel switching, (III) carbon capture utilization and storage, and (IV) reduction of the clinker-to-cement ratio. For concrete production and its end-uses common proposed measures include (V) alternative binders, (VI) material and construction efficiency and (VII) CO2 uptake by concrete.
While the literature shows an emerging consensus around technical solutions for decarbonization, there was less clarity about preferred policy solutions and key barriers. The reviewed studies consistently focused on technical solutions and roadmaps to achieve decarbonization, but often omitted discussion of barriers to implementation or specific policy actions to overcome them. Further research is needed to consider the feasibility and costs of implementation; identify potential points of entry for policy actions at different jurisdictional scales; and identify enforcement needs.
The abundant post-earthquake data from the Canterbury, New Zealand (NZ) area is poised for use with machine learning (ML) to further advance our ability to better predict and understand the effects ...of liquefaction. Liquefaction manifestation is one of the identifiable effects of liquefaction, a nonlinear phenomenon that is still not well understood. ML algorithms are often termed as “black-box” models that have little to no explainability for the resultant predictions, making them difficult for use in practice. With the SHapley Additive exPlanations (SHAP) algorithm wrapper, mathematically backed explanations can be fit to the model to track input feature influences on the final prediction. In this paper, Random Forest (RF) is chosen as the ML model to be utilized as it is a powerful non-parametric classification model, then SHAP is applied to calculate explanations for the predictions at a global and local feature scale. The RF model hyperparameters are optimized with a two-step grid search and a five-fold cross-validation to avoid overfitting. The overall model accuracy is 71% over six ordinal categories predicting the Canterbury Earthquake Sequence measurements from 2010, 2011, and 2016. Insights from the SHAP application onto the RF model include the influences of PGA, GWT depths, and SBTs for each ordinal class prediction. This preliminary exploration using SHAP can pave the way for both reinforcing the performance of current ML models by comparing to previous knowledge and using it as a discovery tool for identifying which research areas are pertinent to unlocking more understanding of liquefaction mechanics.
Electric vehicle (EV) adoption is a key action toward reducing global greenhouse gas emissions from the transport sector, enabling a shift from a fossil fuel intensive on-road sector to a material ...intensive one, especially for critical minerals used in lithium-ion batteries: lithium, cobalt, and nickel. Recent literature has manly focused on forecasting future EV demand and subsequent global battery and critical mineral requirements without modeling which countries will produce the EVs. The Model for International Electric Vehicle Trade (MONET) is a policy-scenario model that combines up-to-date EV demand forecasts, light-duty vehicle global trade flows under different scenarios, and battery characterization to estimate future EV production and battery requirements per country. Results indicate that future EV global trade will be characterized by trade within regional blocks, with contrasting results: North America will be a big producer that will still require imports to meet their demand, Europe will be a big trade region within itself, Japan and South Korea will be big exporters of EVs, and China’s production could go almost entirely to satisfy their domestic supply. Different scenarios show variability according to changes in global trade flows, which are affected by economic and geopolitical events. A major insight reflected in MONET is that an increase in demand for EVs in one country does not translate to a proportional increase in production in the same country. MONET helps to inform which countries will be major producers of EVs by vehicle size, and the amount of battery capacity they will need to secure. Future expansion of MONET includes critical materials estimations based on future battery chemistry development.
Life cycle assessment (LCA) has been recognised as an important environmental systems analysis tool due to its potential for providing systematic results about the environmental impacts of ...alternative production and consumption systems that can lead to decisions towards greater sustainability in both private and public-policy contexts. However, LCA has been under increased scrutiny due to the wide range of published results on similar systems, such as biofuels, which can be contrasting. This variability is, in part, due to the proliferation of guidelines that have emerged over the last 20 years, which may undermine the perceived robustness of LCA as a decision-support tool. Following some interesting discussions on this topic in different fora, we took the pulse of the LCA community
via
a survey. We received 124 responses from respondents who varied in their background and experience in LCA (most were academics and/or had more than 10 years' experience), as well as in their opinions on whether they saw the inconsistency of published results problematic, or not, for decision making. Results suggest that respondents are of the opinion that (i) there is no single right way of performing LCA; (ii) the ISO 14040-44 standards were failing in their guiding of LCA practice, and that (iii) further efforts in harmonizing LCA practice would be beneficial, despite mixed opinions shown by respondents, which indicates the divisive nature of this topic in the LCA community. For example, there was no clear agreement on whether the significant flexibility with which practitioners perform LCA undermines its validity as a robust tool for decision making, though practitioners concerned with greenwashing were unified in the need for improved guidelines and harmonisation. Further harmonisation would help to ensure consistency in the application of the tool by practitioners which, in turn, would ensure results would be less variable, arguably more meaningful, and less prone to greenwashing. It is likely that methodological issues will remain unresolved in the near future, as some practitioners value the flexibility with which the ISO standards can be applied, even if that leads to inconsistent results. We recommended tighter standardization.
LCA has been recognised as an important environmental systems analysis tool. However, the variability in its practice enables greenwashing, and counterproductive decisions that fall short of guiding sustainable production and consumption systems.
Life cycle assessment (LCA) has been recognised as an important environmental systems analysis tool due to its potential for providing systematic results about the environmental impacts of ...alternative production and consumption systems that can lead to decisions towards greater sustainability in both private and public-policy contexts. However, LCA has been under increased scrutiny due to the wide range of published results on similar systems, such as biofuels, which can be contrasting. This variability is, in part, due to the proliferation of guidelines that have emerged over the last 20 years, which may undermine the perceived robustness of LCA as a decision-support tool. Following some interesting discussions on this topic in different fora, we took the pulse of the LCA community via a survey. We received 124 responses from respondents who varied in their background and experience in LCA (most were academics and/or had more than 10 years' experience), as well as in their opinions on whether they saw the inconsistency of published results problematic, or not, for decision making. Results suggest that respondents are of the opinion that (i) there is no single right way of performing LCA; (ii) the ISO 14040-44 standards were failing in their guiding of LCA practice, and that (iii) further efforts in harmonizing LCA practice would be beneficial, despite mixed opinions shown by respondents, which indicates the divisive nature of this topic in the LCA community. For example, there was no clear agreement on whether the significant flexibility with which practitioners perform LCA undermines its validity as a robust tool for decision making, though practitioners concerned with greenwashing were unified in the need for improved guidelines and harmonisation. Further harmonisation would help to ensure consistency in the application of the tool by practitioners which, in turn, would ensure results would be less variable, arguably more meaningful, and less prone to greenwashing. It is likely that methodological issues will remain unresolved in the near future, as some practitioners value the flexibility with which the ISO standards can be applied, even if that leads to inconsistent results. We recommended tighter standardization.
Many Chilean cities suffer from high air pollution from industrial, mobile, and residential wood-burning sources. Several studies have linked PM
air pollution exposure to higher mortality risk from ...cardiovascular, pulmonary, and lung cancer causes. In recent years, Chile has developed an extensive air pollution monitoring network to enforce air quality standards for PM
, allowing the study of the medium-term association between PM
and mortality.
A negative binomial regression model was used to study the association between 3-year average PM
concentrations and age-adjusted mortality rates for 105 of the 345 municipalities in Chile. Models were fitted for all (ICD10 A to Q codes), cardiopulmonary (I and J), cardiovascular (I), pulmonary (J), cancer (C), and lung cancer (C33-C34) causes; controlling for meteorological, socioeconomic, and demographic characteristics.
A significant association of PM
exposure with cardiopulmonary (relative risk for 10 µg/m
PM
: 1.06; 95% confidence interval = 1.00, 1.13) and pulmonary (1.11; 1.02, 1.20) age-adjusted mortality rates was found. Cardiovascular (1.06; 0.99, 1.13) and all causes (1.02; 0.98, 1.07) were positive, but not significant. No significant association was found between cancer and lung cancer. The positive associations remained even when controlling for multiple confounding factors, model specifications, and when considering different methods for exposure characterization. These estimates are in line with results from cohort studies from the United States and European studies.
Three-year average PM
exposure is positively associated with the age-adjusted mortality rate for cardiopulmonary and cardiovascular causes in Chile. This provides evidence of the medium-term exposure effect of fine particles on long-term mortality rates.
We aimed to investigate biomarkers and predictive factors for visual and anatomical outcome in patients with naïve diabetic macular edema (DME) who underwent small gauge pars plana vitrectomy (PPV) ...with internal limiting membrane (ILM) peeling as a first line treatment.
Multicenter, retrospective, interventional study.
120 eyes from 120 patients with naïve DME treated with PPV and ILM peeling with a follow up of 24 months.
Change in baseline best corrected visual acuity (BCVA) and central subfoveal thickness (CST) 1, 6, 12 and 24 months after surgery. Predictive value of baseline BCVA, CST, optical coherence tomography (OCT) features (presence of subretinal fluid (SRF) and photoreceptor damage), and time between DME diagnosis and surgery. Additional treatment for DME needed. Intra- and post-operative complications (cataract rate formation, increased intraocular pressure).
The correlation between baseline characteristics and BCVA response (mean change from baseline; categorized improvement ≥5 or ≥10; Early Treatment Diabetic Retinopathy Study (ETDRS) letters) 12 and 24 months after surgery.
Mean BCVA was 0.66 ± 0.14 logMAR, 0.52 ± 0.21 logMAR, and 0.53 ± 0.21 logMAR (p<0.001) at baseline, 12 and 24 months, respectively. Shorter time from DME diagnosis until PPV (OR: 0.98, 95% CI: 0.97-0.99, p<0.001) was a predictor for good functional treatment response (area under the curve 0.828). For every day PPV is postponed, the patient's chances to gain ≥5 letters at 24 months decrease by 1.8%. Presence of SRF was identified as an anatomical predictor of a better visual outcome, (OR: 6.29, 95% CI: 1.16-34.08, p = 0.033). Safety profile was acceptable.
Our results reveal a significant functional and anatomical improvement of DME 24 months after primary PPV, without the need for additional treatment. Early surgical intervention and presence of SRF predict good visual outcome. These biomarkers should be considered when treatment is chosen.
Background. Antiretroviral therapy (ART)-mediated immune reconstitution fails to restore the capacity of the immune system to spontaneously control human immunodeficiency virus (HIV) replication. ...Methods. A total of 23 HIV type 1 (HIV-1)-infected, virologically suppressed subjects receiving ART (CD4⁺ T-cell count, >450 cells/μL) were randomly assigned to have 180 μg/week (for arm A) or 90 μg/week (for arm B) of pegylated (Peg) interferon alfa-2a added to their current ART regimen. After 5 weeks, ART was interrupted, and Peg-interferon alfa-2a was continued for up to 12 weeks (the primary end point), with an option to continue to 24 weeks. End points included virologie failure (viral load, ≥400 copies/mL) and adverse events. Residual viral load and HIV-1 DNA integration were also assessed. Results. At week 12 of Peg-interferon alfa-2a monotherapy, viral suppression was observed in 9 of 20 subjects (45%), a significantly greater proportion than expected (arm A, P =. 0088; arm B, P =. 0010; combined arms, P< .0001). Over 24 weeks, both arms had lower proportions of subjects who had viral load, compared with the proportion of subjects in a historical control group (arm A, P =. 0046; arm B, P =.0011). Subjects who had a sustained viral load of <400 copies/mL had decreased levels of integrated HIV DNA (P =.0313) but increased residual viral loads (P =.0078), compared with subjects who experienced end-point failure. Conclusions. Peg-interferon alfa-2a immunotherapy resulted in control of HIV replication and decreased HIV-1 integration, supporting a role for immunomediated approaches in HIV suppression and/or eradication.
The aim of this paper is to assess several pathways of a harmonised European policy framework for supporting renewable electricity (RES-E) in a 2030 horizon according to different criteria. The ...pathways combine two main dimensions: degrees of harmonisation and instruments and design elements. A quantitative model-based analysis with the Green-X model is provided. The results of the simulations show that there are small differences between the evaluated cases regarding effectiveness. All the policy pathways score similarly with respect to RES-E deployment, i.e., with different degrees of harmonisation and whether using a feed-in tariff, a feed-in premium, a quota system with banding or a quota without banding scheme. In contrast, the policy costs clearly differ across the pathways, but the differences can mostly be attributed to the instruments rather than to the degrees of harmonisation. This is also the case with other criteria (static and dynamic efficiency and the socioeconomic and environmental benefits in terms of CO2 emissions and fossil fuels avoided). Both the degree of harmonisation and the choice of instrument influence the distribution of support costs across countries. Finally, our findings suggest that keeping strengthened national support leads to similar results to other policy pathways.
•Pathways of a harmonised European policy framework for renewable electricity in 2030.•Two main dimensions: degrees of harmonisation and instruments.•A quantitative model-based analysis based on the Green-X model.•Small differences between the pathways regarding the effectiveness criterion.•Important differences between pathways regarding other assessment criteria.
Herein, we report on the stabilizing effect of water and the chiral self-assembly mode of a cholesterol-based low-molecular-weight supramolecular organogelator. Dynamic rheology experiments performed ...on gels prepared in methanol and methanol–water mixtures showed an enhanced strength and rigidity in the presence of water, in line with the thermal stability previously observed. Morphological characterization experiments (scanning electron microscopy and X-ray powder diffraction) were performed on aerogels obtained after solvent extraction with supercritical CO
2
. Concentration- and temperature-dependent proton nuclear magnetic resonance and electronic circular dichroism experiments confirmed that the molecules of gelator self-assemble with a dominant right-handed helicity through intermolecular hydrogen bond interactions between the carbamate groups, and that the addition of water does not affect either the mode of assembly or the chirality of the supramolecular structure. Computational simulation experiments allowed us to propose a mode of self-assembly compatible with the experimental results, which involves a unidimensional head-to-tail stacking of molecules. A methanolic gel was successfully used as a molecular template for the in situ hydrolytic sol-gel polymerization of tetraethyl orthosilicate giving rise to silica nanotubes with an internal diameter of 7 nm.
Highlights
Water effect on a low-molecular-weight gel based on cholesterol and a benzyloxycarbamate group.
Water increases the thermostability, strength, and rigidity of a supramolecular organogel.
Intermolecular H-bonding interactions are involved in the 1D chiral self-assembly.
The organogel was used as a template for in situ sol-gel polymerization of TEOS into silica nanotubes.
The presence of water does not affect the mode of self-assembly.
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