This paper presents the "Resultado Operativo (RO)" method as a field-tested cost management methodology designed to complement Earned Value Management (EVM) in construction projects. While EVM provides cumulative trend indicators based on a fixed Performance Measurement Baseline (PMB), RO delivers a bottom-up, dynamic, and iterative assessment of project profitability by comparing planned, actual, and forecasted revenue, direct and indirect costs, and the resulting operating margin on a time, phase, and resource basis. The integration of RO with EVM establishes a dual control layer: strategic forecasting through EVM and tactical cost-profit visibility through RO, with execution-based RO insights informing the interpretation and calibration of EVM forecasts. This combined approach enhances forecast accuracy, strengthens budget discipline, and promotes cost transparency, aligning operational decisions with broader project objectives. A case study of a high-rise residential building in Lima, Peru, demonstrates how this integration supports responsive decision making, particularly in subcontractor-intensive and margin-sensitive environments, representative of many emerging and mixed-market construction contexts, contributing to the ongoing advancement of project control practices.
Dredged material (DM) refers to sediment that is excavated from the bottom of the harbor to maintain navigable waterways for shipping and port operations. Over time, sediment accumulates and must be removed to keep channels deep enough for vessels. DM currently has limited applications as a substitute for soils, owing to its variable geotechnical, physical, and chemical characteristics. Environmental and structural challenges are presented by using DM as a construction medium; its low shear strength properties and low hydraulic conductivity make it undesirable as a load-bearing material. A study was conducted to investigate the geotechnical and plant growth properties of raw and stabilized DM from Maryland as possible media for vegetated earthen berms (i.e., infiltration berms). Saturated hydraulic conductivity, unsaturated hydraulic conductivity, and unconfined compression tests were conducted to measure the geotechnical properties and use the data to model a berm in a finite element program. DM amended with straw experienced increases in both hydraulic conductivity and undrained shear strength while providing adequate allowable water content to promote vegetation, without creating any slope stability problems.
The potential to source thermal energy from buried infrastructure such as tunnels and metro stations may offer significant potential to reduce the carbon dioxide emissions of heating and cooling, and reduce the costs associated with dedicated drilling for traditional ground-sourced systems. However, this remains a niche approach with few commercial schemes globally, partly due to high initial costs, long payback periods, technical uncertainties and the need to minimise construction risk and delays. To help address these challenges, the energy resource potential, technical and economic barriers and ways of overcoming them were examined for tunnels beneath Manchester and Crewe that were proposed as part of the HS2 Phase 2b railway construction. A worthwhile thermal resource was established, along with enthusiasm for use of the energy by the infrastructure developer and third parties in the vicinity. The economic case is set out, which establishes financial viability but with significant uncertainty based on future market conditions. This demonstrates the need for a supportive future policy environment to encourage the uptake of all available heat sources.
Post-combustion capture (PCC) of CO2 is widely recognized as the most mature technology to mitigate CO2 emissions from existing fossil fuel-based power plants and industrial sources, and successful deployment will predominantly rely on the ability of the PCC plant to consistently achieve high capture fractions. To this end, the performance modeling study presented herein is the first attempt to identify engineering options for long-term, cost-effective windows for zero fossil CO2 stack emission PCC operation, when 100% of the added fuel CO2 (100% of the fossil CO2) is captured, in key industrial applications including combined cycle gas turbine (CCGT) power plants, steel, cement, energy from waste (EfW), and oil refining (fluidized catalytic crackers). Furthermore, low-cost designs for effective solvent recovery through thermal reclaiming with effective energy recovery are analyzed for the first time for nonproprietary, open-art aqueous MEA solvent at 35% w/w (unloaded). At 100% capture of the added fuel CO2, low lean loadings (between 0.1 and 0.12 molCO2/molMEA) enhance mass transfer in the absorber, while a raised desorber pressure of 2.4 bar limits excessive energy consumption. In fact, for an absorber packing height of 20 m (2 x 10 m beds), the optimum specific reboiler duty (SRD) to capture 100% of the added fuel CO2 (zero fossil CO2 stack operation) was found to lie between 3.62 and 3.96 GJ/tCO2, while for a 3 x 8 m bed absorber, i.e., 24 m, the SRD drops to 3.46-3.75 GJ/tCO2, both cases well within the range of reported energy penalty for 90-95% capture, which has significantly higher residual CO2 emissions. Furthermore, we analyzed two strategies of continuously operating a thermal reclaimer, i.e., single-stage and two-stage reclaiming systems (the first operates at stripper pressure while the second one at atmospheric) with effective energy integration and consideration of both volatile and nonvolatile components. Two-stage reclaiming can substantially reduce water addition compared to single-stage reclaiming from 100 to 400% of the reclaimer solvent flow to 0-50%. Yet, there exists a trade-off, namely, the greater the MEA recovery, the greater the uptake of volatile thermal degradation products. For example, in the case of single-stage reclaiming operation, for similar to 90% MEA recovery, approximately 35% of the HEEDA is recycled to the PCC, and when MEA recovery increases to similar to 95%, the associated HEEDA return reaches similar to 52%. Effective integration of thermal reclaiming with the desorber results in a small additional electricity output penalty, i.e., ranging from 0.3 to 1.13% relative to the output with capture but with no reclaiming. However, it should be noted that a solvent management technique is essential to an amine-based PCC as accumulation of degradation products will affect capture efficiency and associated energy costs and eventually will be a showstopper. Overall, the study suggests that industrial applications fitted with PCC can achieve deep decarbonization in a cost-efficient manner with effective solvent degradation remedial strategies and contrary to the consensus that high capture fractions are associated with excessive energy penalties. Hence, the results can provide meaningful information for engineering deployment and policy decision making.
Unwarned population distributions accounting for routine human activities are needed to address many global human security challenges, including disasters, conflict, and infrastructure demand. LandScan High Definition (LSHD) supports this need through gridded ambient population estimates that measure average human presence between daytime and nighttime at a high spatial resolution of 3 arcseconds (approximately 90 m). Although LSHD has traditionally been produced on a country-specific basis, advances in global foundational data and computational resources now enable scaling its methodology to the world. Combining aspects of top-down and bottom-up gridded population methods, LSHD allocates subnational population totals from authoritative statistics to built-up areas based on occupancy estimates for multiple facility types (e.g., residential, commercial) and then reaggregates these estimates to a global population grid. We scale this approach by organizing the LSHD data stack into a 1° resolution tileset of vector analytic features, enabling an efficient and repeatable workflow for all countries worldwide. Examining the Philippines as an output of the global LSHD baseline dataset, we contrast unwarned and residential (WorldPop) population distributions by (1) exploring a practical application of flood risk assessment and (2) evaluating their congruence with outcomes of collective human activities (subnational CO2 emissions). Finally, we discuss plans to address current LSHD limitations through data/modeling and uncertainty quantification improvements and provide outlook for workflow automation and extending the model to social, demographic and economic population characteristics.
