This paper presents a study of cement replacement by sugar cane bagasse ash (SCBA) in industrial scale aiming to reduce the CO2 emissions into the atmosphere. SCBA is a by-product of the ...sugar/ethanol agro-industry abundantly available in some regions of the world and has cementitious properties indicating that it can be used together with cement. Recent comprehensive research developed at the Federal University of Rio de Janeiro/Brazil has demonstrated that SCBA maintains, or even improves, the mechanical and durability properties of cement-based materials such as mortars and concretes. Brazil is the world’s largest sugar cane producer and being a developing country can claim carbon credits. A simulation was carried out to estimate the potential of CO2 emission reductions and the viability to issue certified emission reduction (CER) credits. The simulation was developed within the framework of the methodology established by the United Nations Framework Convention on Climate Change (UNFCCC) for the Clean Development Mechanism (CDM). The State of São Paulo (Brazil) was chosen for this case study because it concentrates about 60% of the national sugar cane and ash production together with an important concentration of cement factories. Since one of the key variables to estimate the CO2 emissions is the average distance between sugar cane/ethanol factories and the cement plants, a genetic algorithm was developed to solve this optimization problem. The results indicated that SCBA blended cement reduces CO2 emissions, which qualifies this product for CDM projects.
These recommendations have been prepared by the corresponding working group within RILEM TC 287-CCS “Early-age and long-term crack width analysis in RC structures”, following work by the previously ...ceased RILEM TC 254-CMS “Thermal cracking of massive concrete structures”. This recommendations document is developed in complementarity to the state-of-the-art report of RILEM TC 254-CMS and aims to provide expert advice and suggestions to engineers and scientists interested in modelling the thermo-chemo-mechanical behaviour of massive concrete structures since concrete casting. Recommendations regarding geometrical characteristics and complexities, concrete properties and appropriate material models, boundary conditions and loads, and numerical model peculiarities with relevance to the simulation of the thermo-chemo-mechanical behaviour of massive concrete structures are given herein. The recommendations have been reviewed and approved by all members of the TC 287-CCS.
Background
Clinical opioid overdose risk prediction models can be useful tools to reduce the risk of overdose in patients prescribed long-term opioid therapy (LTOT). However, evolving overdose risk ...environments and clinical practices in addition to potential harmful model misapplications require careful assessment prior to widespread implementation into clinical care. Models may need to be tailored to meet local clinical operational needs and intended applications in practice.
Objective
To update and validate an existing opioid overdose risk model, the Kaiser Permanente Colorado Opioid Overdose (KPCOOR) Model, in patients prescribed LTOT for implementation in clinical care.
Design, Setting, and Participants
The retrospective cohort study consisted of 33, 625 patients prescribed LTOT between January 2015 and June 2019 at Kaiser Permanente Colorado, with follow-up through June 2021.
Main Measures
The outcome consisted of fatal opioid overdoses identified from vital records and non-fatal opioid overdoses from emergency department and inpatient settings. Predictors included demographics, medication dispensings, substance use disorder history, mental health history, and medical diagnoses. Cox proportional hazards regressions were used to model 2-year overdose risk.
Key Results
During follow-up, 65 incident opioid overdoses were observed (111.4 overdoses per 100,000 person-years) in the study cohort, of which 11 were fatal. The optimal risk model needed to risk-stratify patients and to be easily interpreted by clinicians. The original 5-variable model re-validated on the new study cohort had a bootstrap-corrected
C
-statistic of 0.73 (95% CI, 0.64–0.85) compared to a
C
-statistic of 0.80 (95% CI, 0.70–0.88) in the updated model and 0.77 (95% CI, 0.66–0.87) in the final adapted 7-variable model, which was also well-calibrated.
Conclusions
Updating and adapting predictors for opioid overdose in the KPCOOR Model with input from clinical partners resulted in a parsimonious and clinically relevant model that was poised for integration in clinical care.
We present the results of a detailed non-LTE analysis of the ultraviolet and optical spectrum of the O6.5 Iaf+ star HD 153919 – the mass donor in the high-mass X-ray binary 4U1700-37. We find that ...the star has a luminosity log$(L_{\ast}/L_{\odot})=5.82 \pm 0.07$, $T_{\rm eff}=35\,000 \pm 1000$ K, radius $R_{\ast}=21.9^{+1.3}_{-0.5}~R_{\odot}$, mass-loss rate $\dot{M}=9.5\times 10^{-6}~M_{\odot}$ yr-1, and a significant overabundance of nitrogen (and possibly carbon) relative to solar values. Given the eclipsing nature of the system these results allow us to determine the most likely masses of both components of the binary via Monte Carlo simulations. These suggest a mass for HD 153919 of $M_{\ast} = 58 \pm 11~M_{\odot}$ – implying the initial mass of the companion was rather high ($\ga$60 $M_{\odot}$). The most likely mass for the compact companion is found to be $M_x =2.44\pm 0.27~M_{\odot}$, with only 3.5 per cent of the trials resulting in a mass less than 2.0 $M_{\odot}$ and none less than 1.65 $M_{\odot}$. Such a value is significantly in excess of the upper observational limit to the masses of neutron stars of 1.45 $M_{\odot}$ found by Thorsett & Chakrabarthy (CITE), although a mass of 1.86 $M_{\odot}$ has recently been reported for the Vela X-1 pulsar (Barziv et al. CITE). Our observational data is inconsistent with the canonical neutron star mass and the lowest black hole mass observed ($\ga$4.4 $M_{\odot}$; Nova Vel). Significantly changing observational parameters can force the compact object mass into either of these regimes but, given the strong proportionality between $M_{\ast}$ and Mx, the O-star mass changes by factors of greater than 2, well beyond the limits determined from its evolutionary state and surface gravity. The low mass of the compact object implies that it is difficult to form high mass black holes through both the Case A & B mass transfer channels and, if the compact object is a neutron star, would significantly constrain the high density nuclear equation of state.
The performance of cement mortars using manufactured fine aggregates produced by cone crushing or impact crushing has been compared to that of mortars prepared from a natural sand control-sample. ...Samples from both crusher products have been additionally subjected to classification for partial removal of fines, being also used in preparing mortars. Particle shape analyses indicated that material produced by impact crushing presented intermediate sphericity and aspect ratio, between those found in natural fine aggregate and cone-crushed material, and that the aspect ratio of the cone-crushed material increased for finer particle sizes. The unclassified impact crusher product presented the highest packing density, and mortars produced from it had comparatively low porosity and low absorptivity and the highest unconfined compressive strength. The classified product from cone crushing presented low packing density and mortars were characterized by the highest porosities, absorptivities and lowest unconfined compressive strength, probably mostly due to its poor particle shapes. Modeling of the stress–strain response with scalar damage mechanics showed that manufactured aggregate produced from classification of the cone crusher yielded a mortar with highly inelastic deformation response, whereas mortars produced from unclassified product of impact crushing showed more elastic deformation response. Results were also analyzed in light of de Larrard's Compressible Packing Model.
The theoretical motivation for exotic stable massive particles (SMPs) and the results of SMP searches at non-collider facilities are reviewed. SMPs are defined such that they would be sufficiently ...long-lived so as to still exist in the cosmos either as Big Bang relics or secondary collision products, and sufficiently massive such that they are typically beyond the reach of any conceivable accelerator-based experiment. The discovery of SMPs would address a number of important questions in modern physics, such as the origin and composition of dark matter and the unification of the fundamental forces. This review outlines the scenarios predicting SMPs and the techniques used at non-collider experiments to look for SMPs in cosmic rays and bound in matter. The limits so far obtained on the fluxes and matter densities of SMPs which possess various detection-relevant properties such as electric and magnetic charge are given.
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