Rate-Independent Damage in Thermo-Viscoelastic Materials with Inertia

We present a model for rate-independent, unidirectional, partial damage in visco-elastic materials with inertia and thermal effects. The damage process is modeled by means of an internal variable, governed by a rate-independent flow rule. The heat equation and the momentum balance for the displacements are coupled in a highly nonlinear way. Our assumptions on the corresponding energy functional also comprise the case of the Ambrosio\u2013 Tortorelli phase-field model (without passage to the brittle limit). We discuss a suitable weak formulation and prove an existence theorem obtained with the aid of a (partially) decoupled time-discrete scheme and variational convergence methods. We also carry out the asymptotic analysis for vanishing viscosity and inertia and obtain a fully rate-independent limit model for displacements and damage, which is independent of temperature

Factors influencing Safety on Construction Projects (fSCPs): types and categories

Due to the fact of activity, environment and work dynamics, the construction industry is characterised by high accident rates. Different initiatives have emerged to reduce these figures, which focus on using new methodologies and technologies for safety management. Therefore, it is essential to know the key factors and their influence on safety in construction projects (fSCPs) to focus efforts on these elements. Through a systematic literature review, based on PRISMA methodology, this article identifies, describes and categorises 100 factors that affect construction safety. It thus contributes by providing a comprehensive general framework, unifying previous studies focused on specific geographic areas or case studies with factors not considered or insufficiently disaggregated, along with an absence of classifications focused on understanding where and how factors affect the different dimensions of construction projects. The 100 factors identified are described and categorised according to the dimensions and aspects of the project in which these have an impact, along with identifying whether they are shaping or immediate factors or originating influences for the generation of accidents. These factors, their description and classification are a key contribution to improving the systematic creation of safety and generating training and awareness materials to fully develop a safety culture in organisations.This research was funded by Proyecto VRIEA-PUCV (grant number 039.429/2021). This work was supported by the CONICYT to F.M., who was the beneficiary of a pre-doctoral grant (CONICYT—PCHA/International Doctorate/2019-72200306) and by the Ministry of Science, Innovation and Universities of Spain (MICIU) through the BIMIoTICa project (RTC-2017-6454-7). The authors also acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa Programme for Centres of Excellence in R&D (CEX2018-000797-S)”. Institution: Vicerrectoría de Investigación y Estudios avanzados - Pontificia Universidad Católica de Valparaíso (VRIEA-PUCV) Code Project: 039.429/2021.Peer ReviewedPostprint (published version

Dampak Polusi Udara terhadap Kesehatan dan Kesiapan Pertahanan Negara di Provinsi DKI Jakarta

Air pollution in DKI Jakarta Province has reached alarming levels, threatening the health and quality of life of millions of residents and damaging the integrity of national defense preparedness. As the capital and center of Indonesian government, Jakarta plays an important role in the country's defense and security structure. This research was conducted to understand and evaluate the complex impacts of air pollution, which relate not only to public health but also to defense readiness. Through empirical data analysis, interviews with stakeholders, and the application of geospatial intelligence from satellite imagery, this research found various variables that correlate between air pollution, public health, and defense readiness. One of the main findings is that high levels of air pollution have a significant impact on public health conditions, which in turn can disrupt the country's defense readiness. Therefore, these results demonstrate the need for comprehensive and coordinated mitigation actions between various parties, including the provincial government, central government, and the military. These policies and actions should focus on protecting public health, preserving critical military infrastructure, and preparing the country to face additional challenges that may arise, such as climate change. In an increasingly interconnected and complex global context, this research highlights the urgency for a more holistic approach to addressing the problem of air pollution and its multifaceted impact

Understanding asteroid collisional history through experimental and numerical studies

Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect

Search For Companions Of Nearby Isolated Galaxies

The radial velocities are measured for 45 galaxies located in the neighborhoods of 29 likely isolated galaxies in a new catalog. We find that about 85% of these galaxies actually are well isolated objects. 4% of nearby galaxies with V_LG<3500 km/s are this kind of cosmic "orphan".Comment: 7 pages, 2 figure

Missing OH source in a suburban environment near Beijing: observed and modelled OH an HO2 concentrations in summer 2006

Measurements of ambient OH and HO₂ radicals were performed by laser induced fluorescence (LIF) during CAREBeijing2006 (Campaigns of Air Quality Research in Beijing and Surrounding Region 2006) at the suburban site Yufa in the south of Beijing in summer 2006. On most days, local air chemistry was influenced by aged air pollution that was advected by a slow, almost stagnant wind from southern regions. Observed daily maxima of OH and HO₂^* were in the range of (4–17) × 10⁶ cm^&minus;3 and (2–24) × 10⁸ cm^&minus;3, respectively. During daytime, OH reactivities were generally high (10–30 s^&minus;1) and mainly contributed by VOCs and their oxidation products. The comparison of modelled and measured HO_x concentrations reveals a systematic underprediction of OH as a function of NO. A large discrepancy of a factor 2.6 is found at the lowest NO concentration encountered (0.1 ppb), whereas the discrepancy becomes insignificant above 1 ppb NO. This study extends similar observations from the Pearl-River Delta (PRD) in South China to a more urban environment. The OH discrepancy at Yufa can be resolved, if NO-independent additional OH recycling is assumed in the model. The postulated Leuven Isoprene Mechanism (LIM) has the potential to explain the gap between modelled and measured OH at Beijing taking into account conservative error estimates, but still lacks experimental confirmation. This and the hereby unresolved discrepancy at PRD suggest that other VOCs besides isoprene might be involved in the required, additional OH recycling. Fast primary production of RO_x radicals up to 7 ppb h^&minus;1 was determined at Beijing which was dominated by the photolysis of O₃, HONO, HCHO, and dicarbonyls. For a special case, 20 August, when the plume of Beijing city was encountered, a missing primary HO_x source (≈ 3 ppb h^&minus;1) was determined under high NO_x conditions similar to other urban areas like Mexico city. CAREBeijing2006 emphasizes the important role of OVOCs as a radical source and sink, and the need for further investigation of the chemical degradation of VOCs in order to better understand radical chemistry in VOC-rich air

The Widening Health Care Gap Between High- and Low-Wage Workers

Compares the changes in insurance status, out-of-pocket costs, access to care, use of prescription drugs, and health-related outcomes of low-wage workers and high-wage workers between 1996 and 2003. Discusses the implications of the growing disparities