Reusing ceramic wastes in concrete Pacheco-Torgal, F.; Jalali, S.
Construction & building materials,
05/2010, Letnik:
24, Številka:
5
Journal Article
Recenzirano
The ceramic industry is known to generate large amounts of calcined-clay wastes each year. So far a huge part is used in landfills. Reusing these wastes in concrete could be a win–win situation. For ...one hand by solving the ceramic industry waste problem and at the same time leading to a more sustainable concrete industry by reducing the use of non renewable resources like cement and aggregates and avoiding environmental problems related to land filled wastes. This paper examines the feasibility of using ceramic wastes in concrete. Results show that concrete with 20% cement replacement although it has a minor strength loss possess increase durability performance. Results also show that concrete mixtures with ceramic aggregates perform better than the control concrete mixtures concerning compressive strength, capillary water absorption, oxygen permeability and chloride diffusion thus leading to more durable concrete structures.
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•We report a new code for the calculation of the elastic constants of cubic systems.•This code is reliable because it uses single deformation instead of rhombohedral strain.•The ...elastic constants of various cubic crystals are calculated to show the effectiveness of the code.
In this paper we present details of our developed open source software, cubic-elastic, for the calculation of the elastic constants (ECs) of cubic crystals. The comparison of the calculated ECs for various types of cubic systems by this software with those from the other available softwares as well as experimentally measured results confirms that our code can predict reliable results. The success of our code originates from its use of single deformation. The other codes usually use rhombohedral strain (RS). RS leads to 3B0+4C44 expression. Hence, RS systematically adds error to the C44 through the bulk modulus calculations, and thereby may not be mathematically an appropriate approach. The total energy is accurately calculated by the WIEN2k within the highly accurate full-potential (linearized) augmented plane-waves plus local orbitals method. The ECs are calculated by the second-order derivatives of the fitted polynomials to the calculated total energies with respect to the elements of strain tensors at zero strains. We have presented the theoretical background and methodology of the cubic-elastic. We have validated the software by taking a variety of cubic samples into consideration and calculated their ECs. The zero bulk error calculations show that the results obtained from the cubic-elastic are in good agreement with the available experimental data and the previous theoretical results and predicts the sign of elastic constants correctly. The calculated Cauchy’s pressure (C″) and Poisson’s ratio (ν) of LaS predict that it is an ionic compound. This prediction is in agreement (disagreement) with the previous ionic (covalent) bonds prediction deduced from previous ν (C″).
Organic-Inorganic perovskites CsPbX3 (X = Cl, Br, I) are investigated for their potential ability and use as solar cells and energy storage materials, using density function theory, generalized ...gradient approximation and modified Becke-Johnson (TB-mBJ) exchange potential. Structural analysis shows that the lattice constant and unit cell volume varies when CsPbX3 (X = Cl, Br, I) change from cubic phase to tetragonal and orthorhombic structures. The electronic properties show that CsPbCl3, CsPbBr3 and CsPbI3 all are semiconductor in with bandgap between 0.79 eV and 2.54 eV. It is also observed that the bandgap changes when the structure changes. Optical properties show that these materials have a good absorption ability of photons due to their narrow bandgaps. The real ε1(ω) and imaginary ε2(ω) parts of their dielectric functions show that CsPbCl3, CsPbBr3 and CsPbI3 also possess a great ability of retaining the energy it absorbs. These properties make them very suitable for solar cells and energy storage applications. These materials also behave as superluminescent material at high photon energy.
•Structural properties of perovskites CsPbX3 (X = Cl, Br, I).•Bandgap analysis for electro-optical applications.•Optical constants are calculated for solar cell applications.
Asphyxia at birth is one of the major causes of morbidity and mortality in all neonates due to various organ dysfunctions, for example, kidneys. Recent advances in this area have suggested new ...urinary proteins for the assessment of renal damage, including beta-2 microglobulin (β2-MG). The aim of this study was to investigate the changes of urinary β2-MG in asphyxiated neonates and to evaluate the value of combined detection of multiple biomarkers in the early diagnosis of acute kidney injury (AKI) in asphyxiated neonates.
This case-control study was performed on 84 term neonates in two control and case groups who were hospitalized at the neonatal intensive care unit. Using the Sarnat scoring system, the asphyxiated neonates were neurologically divided. Renal function tests and urinary β2-MG (uβ2-MG) levels of participants who registered based on inclusion criteria were measured. The data analyzed using descriptive and inferential statistical tests. The diagnostic value of the biomarker was determined using receiver operating characteristic (ROC) curves.
This study showed that uβ2-MG was not a statistically significant difference in both asphyxiated neonates with AKI and non-AKI (p = .085). Whereas, uβ2-MG levels were statistically significant in neurological grading of asphyxiated infants to two groups (p = .013). A new predictor, uβ2-MG and blood urea nitrogen (BUN); named BB1, was substituted as the diagnostic value in neonates with asphyxia with an area under the receiver operating characteristic curve (AUC) (95% CI) of 0.88 (0.76-1.0). This AUC was significantly greater than the value for uβ2-MG associated with AKI (p = .003).
Our findings showed that mutual detection of uβ2-MG levels with BUN should be an early indicator for the diagnosis of renal injury with greater specificity and improved prognostic accuracy after neonatal asphyxia.
Ferroelectricity in metals has advanced since the initial discovery of nonmagnetic ferroelectric-like metal LiOsOFormula: see text, anchored in the Anderson and Blount prediction. However, evaluating ...the spontaneous electric polarization (SEP) of this metal has been hindered by experimental and theoretical obstacles. The experimental challenge arises from difficulties in switching polarization using an external electric field, while the theoretical limitation lies in existing methods applicable only to nonmetals. Zabalo and Stengel (Phys Rev Lett 126:127601, 2021, https://doi.org/10.1103/PhysRevLett.126.127601 ) addressed the experimental obstacle by proposing flexoelectricity as an alternative for practical polarization switching in LiOsOFormula: see text, which requires a critical bending radius similar to BaTiOFormula: see text. In this study, we focus on resolving the theoretical obstacle by modifying the Berry phase and Wannier functions approaches within density functional theory plus modern theory of polarization. By employing these modifications, we calculate the SEP of LiOsOFormula: see text, comparable to the polarization of BaTiOFormula: see text. We validate our predictions using various ways. This study confirms the coexistence of ferroelectricity and metallicity in this new class of ferroelectric-like metals. Moreover, by addressing the theoretical limitation and providing new insights into polarization properties, our study complements the experimental flexoelectricity proposal and opens avenues for further exploration and manipulation of polarization characteristics. The developed approaches, incorporating modified Berry phase and Wannier function techniques, offer promising opportunities for studying and designing novel materials, including bio- and nano-ferroelectric-like metals. This study contributes to the advancement of ferroelectricity in metals and provides a foundation for future research in this exciting field.
Parkinson’s disease (PD) is the second most common age-related neurodegenerative disorder. PD is characterized by progressive loss of dopamine-producing neurons in the substantia nigra (SN) region of ...brain tissue followed by the α-synuclein-based Lewy bodies’ formation. These conditions are manifested by various motor and non-motor symptoms such as resting tremor, limb rigidity, bradykinesia and posture instability, cognitive impairment, sleep disorders, and emotional and memory dysfunctions. Long non-coding RNAs (lncRNAs) are closely related to protein-coding genes and are involved in various biological processes. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) lncRNA is involved in different pathways, including alternative splicing, transcriptional regulation, and post-transcriptional regulation, and also interacts with RNAs as a miRNA sponge. MALAT1 is highly expressed in brain tissues and several lines of evidence suggested it is probably involved in synapse generation and other neurophysiological pathways. This narrative review discussed all aspects of MALAT1-associated mechanisms involved in the PD pathogenesis, i.e., perturbed α-synuclein homeostasis, apoptosis and autophagy, and neuro-inflammation. Lastly, the possible applications of MALAT1 as a diagnostic biomarker and its importance to developing therapeutic strategies were highlighted. The literature search was conducted using neurodegeneration, neurodegenerative disorders, Parkinson’s disease, lncRNA, and MALAT1 as search items in Google Scholar, Web of Knowledge, PubMed, and Scopus up to December 2021.
Post-traumatic stress disorder (PTSD) stands out as a major mental illness; however, little is known about effective policies for mitigating the problem. The importance and complexity of PTSD raise ...critical questions: What are the trends in the population of PTSD patients among military personnel and veterans in the postwar era? What policies can help mitigate PTSD? To address these questions, we developed a system dynamics simulation model of the population of military personnel and veterans affected by PTSD. The model includes both military personnel and veterans in a "system of systems." This is a novel aspect of our model, since many policies implemented at the military level will potentially influence (and may have side effects on) veterans and the Department of Veterans Affairs. The model is first validated by replicating the historical data on PTSD prevalence among military personnel and veterans from 2000 to 2014 (datasets from the Department of Defense, the Institute of Medicine, the Department of Veterans Affairs, and other sources). The model is then used for health policy analysis. Our results show that, in an optimistic scenario based on the status quo of deployment to intense/combat zones, estimated PTSD prevalence among veterans will be at least 10% during the next decade. The model postulates that during wars, resiliency-related policies are the most effective for decreasing PTSD. In a postwar period, current health policy interventions (e.g., screening and treatment) have marginal effects on mitigating the problem of PTSD, that is, the current screening and treatment policies must be revolutionized to have any noticeable effect. Furthermore, the simulation results show that it takes a long time, on the order of 40 years, to mitigate the psychiatric consequences of a war. Policy and financial implications of the findings are discussed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The prevalence of opioid use and misuse has provoked a staggering number of deaths over the past two and a half decades. Much attention has focused on individual risks according to various ...characteristics and experiences. However, broader social and contextual domains are also essential contributors to the opioid crisis such as interpersonal relationships and the conditions of the community and society that people live in. Despite efforts to tackle the issue, the rates of opioid misuse and non-fatal and fatal overdose remain high. Many call for a broad public health approach, but articulation of what such a strategy could entail has not been fully realised. In order to improve the awareness surrounding opioid misuse, we developed a social-ecological framework that helps conceptualise the multivariable risk factors of opioid misuse and facilitates reviewing them in individual, interpersonal, communal and societal levels. Our framework illustrates the multi-layer complexity of the opioid crisis that more completely captures the crisis as a multidimensional issue requiring a broader and integrated approach to prevention and treatment.
Alongside the emergence of COVID-19 in the United States, several reports highlighted increasing rates of opioid overdose from preliminary data. Yet, little is known about how state-level opioid ...overdose death trends and decedent characteristics have evolved using official death records.
We requested vital statistics data from 2018-2020 from all 50 states and the District of Columbia, receiving data from 14 states. Accounting for COVID-19, we excluded states without data past March 2020, leaving 11 states for analysis. We defined state-specific analysis periods from March 13 until the latest reliable date in each state's data, then conducted retrospective year-over-year analyses comparing opioid-related overdose death rates, the presence of specific opioids and other psychoactive substances, and decedents' sex, race, and age from 2020 to 2019 and 2019 to 2018 within each state's analysis period. We assessed whether significant changes in 2020 vs. 2019 in opioid overdose deaths were new or continuing trends using joinpoint regression.
We found significant increases in opioid-related overdose death rates in Alaska (55.3%), Colorado (80.2%), Indiana (40.1%), Nevada (50.0%), North Carolina (30.5%), Rhode Island (29.6%), and Virginia (66.4%) - all continuing previous trends. Increases in synthetic opioid-involved overdose deaths were new in Alaska (136.5%), Indiana (27.6%), and Virginia (16.5%), whilst continuing in Colorado (44.4%), Connecticut (3.6%), Nevada (75.0%), and North Carolina (14.6%). We found new increases in male decedents in Indiana (12.0%), and continuing increases in Colorado (15.2%). We also found continuing increases in Black non-Hispanic decedents in Massachusetts (43.9%) and Virginia (33.7%).
This research analyzes vital statistics data from 11 states, highlighting new trends in opioid overdose deaths and decedent characteristics across 10 of these states. These findings can inform state-specific public health interventions and highlight the need for timely and comprehensive fatal opioid overdose data, especially amidst concurrent crises such as COVID-19.
Key messages:
Our results highlight shifts in opioid overdose trends during the COVID-19 pandemic that cannot otherwise be extracted from aggregated or provisional opioid overdose death data such as those published by the Centres for Disease Control and Prevention.
Fentanyl and other synthetic opioids continue to drive increases in fatal overdoses, making it difficult to separate these trends from any possible COVID-19-related factors.
Black non-Hispanic people are making up an increasing proportion of opioid overdose deaths in some states.
State-specific limitations and variations in data-reporting for vital statistics make it challenging to acquire and analyse up-to-date data on opioid-related overdose deaths. More timely and comprehensive data are needed to generate broader insights on the nature of the intersecting opioid and COVID-19 crises
This work investigates the buckling behavior of circular sandwich plates with tapered cores and functionally graded carbon nanotube (FG-CNT) reinforced composite face sheets under uniform radial ...compression based on the first order shear deformation plate theory. The sandwich plate is assumed to be constituted of a pure polymer core and two FG-CNT reinforced composite layers with constant thickness whose material properties are assumed to be graded through the thickness direction. Different distributions of multi walled CNTs (MWCNTs) in the thickness direction of face sheets are introduced. Effective properties of materials are estimated through the modified form of rule of mixture. In order to determine the distribution of the prebuckling load along the radius, the membrane equation is solved using the shooting method. Subsequently, employing the pseudospectral method, the stability equations are numerically solved to evaluate the critical buckling load. Parametric studies are conducted for various types of CNTs distributions and geometrical parameters under different boundary conditions. The results show that the buckling behavior is significantly influenced by the CNTs distributions, the thickness variation profile, the aspect ratio and the face sheet-to-core thickness ratio. Some conclusions are drawn on the parametric studies with respect to the buckling characteristics.
•The buckling of reinforced circular sandwich plates with tapered cores is studied.•Different distributions of CNTs in the face sheets are introduced.•Buckling behavior is influenced by the CNTs distributions and tapering profile.
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