Material Conditions Research Articles

Vierendeel action in progressive collapse of three-storey RC structures under corner column removal scenario

Previous studies have found that the Vierendeel action (VA) is one of the main mechanisms against progressive collapse of multi-storey reinforcement concrete (RC) frame structures in the event of corner column failure. However, the knowledge remains inadequate in terms of the behavior, mechanism, and quantitative contribution of the VA to the collapse resistance. To fill this gap, quasi-static tests were performed on a 1/3 scale single-storey RC substructure and a three-storey RC substructure with identical geometry, material, reinforcements and boundary conditions under corner column removal scenario. Test results found that, compared with the single-storey substructure experiencing no VA, the three-storey substructure developed additional plastic hinges at the beam ends near the corner column and at the lower end of the corner column as a result of the VA. The ultimate resistance of the three-storey substructure was 10.6% more than the triple ultimate resistance of the single-storey substructure. Then, numerical analysis was conducted to cognize the formation sequence of the plastic hinges and the effect of slabs. Furthermore, two coefficients were defined to reveal the mechanism of the VA in the three-storey substructure, i.e., the displacement-related coefficient ed and the coefficient associated with ultimate resistance eu. Finally, a simplified analytical model was proposed to predict the ultimate resistance of the three-storey structures with consideration of the VA.

Effects of Urban Growth and Urbanization on the Social Environment: Case Study Old and Modern Cities of Yemen

Aim: This research was designed to study the effects of urban growth and urbanization on the social environment (Study of the state of growth and social changes in the old and modern cities of Yemen an example). Background: Yemenis have a rich history of urban centers, which have played a crucial role in trade, crafts, industries, and science. These cities have become distinct areas of cultural development, economic polarization, and cultural radiation. They are considered crucibles for social culturalintegration, nurseries for political growth, and areas for the development of national consciousness. The history of Yemen's cities and urban centers demonstrates the close link between trade, delivery routes, political governance centers, and city growth and development. Some Yemeni historical cities have played a vital role before Islam as political capitals, educators, and seaports. Cities have emerged as a result of the desire to coexist and achieve stability, reflecting spiritual, material, social, and political conditions. The growth of cities and architecture is a reflection of these changes. Methodology: The physical changes in the Republic of Yemen and the identification of the city of Aden were studied by reviewing the studies that monitored these changes and their social, economic and population effects. The study relied on secondary data in the first place. Conclusion: Yemen's population growth rate in 2004 was low at 3.01%, but it remains high due to economic and social developments and changes demographic factors such as fertility, mortality, and migration the growth rate was decreased at 2.20%. The 2004 General Population and Housing Census revealed that the resident population is spread across various governorates, with Ta'izz, Hodeidah, and Ibb having the highest proportions. The General Census of Population and Establishments revealed changes in the relative weight of the provincial population between the 1994 and 2004 censuses, with some governorates experiencing an increase in population relative to the population, while others experienced a decrease. The annual growth rate of the resident population was 3.0%, and the proportion of the young age group increased from 46.2% in 1994 to 51.5% in 2004. The gender ratio in Yemen is 104, with some governorates having a higher proportion of species due to urbanization (male than more than female), employment opportunities, or male labor migration. The Central Statistical Agency predicts that population growth will remain high over the next 20 years, with a natural increase rate of 3.01%. The proportion of married people in the population is higher for both sexes, possibly due to increased living costs and lack of adequate housing.

Bi‐interlayer Strategy for Modulating NiCoP‐based Heterostructure toward High‐performance Aqueous Energy Storage Devices

AbstractNickel‐cobalt (NiCo) phosphides (NCPs) possess high electrochemical activity, which makes them promising candidates for electrode materials in aqueous energy storage devices, such as supercapacitors and zinc batteries. However, the actual specific capacitance and rate capability of NCPs require further improvement, which can be achieved through reasonable heterostructural design and loading conditions of active materials on substrates. Herein, novel hierarchical Bi‐NCP heterogeneous structures with built‐in electric fields consisting of bismuth (Bi) interlayers (electrodeposited on carbon cloth (CC)) were designed and fabricated to ensure the formation of uniform high‐load layered active materials for efficient charge and ion transport. The resulting CC/Bi‐NCP electrodes showed a uniform, continuous, and high mass loading (>3.5 mg) with a superior capacitance reaching 1200 F⋅g−1 at 1 A⋅g−1 and 4129 mF⋅cm−2 at 1 mA⋅cm−2 combined with high‐rate capability and durable cyclic stability. Moreover, assembled hybrid supercapacitors, supercapatteries, and alkaline zinc batteries constructed using these electrodes delivered high energy densities of 64.4, 81.8, and 319.1 Wh·kg−1, respectively. Overall, the constructed NCPs with excellent aqueous energy storage performance are potential for the development of novel transition metal‐based heterostructure electrodes for advanced energy devices.This article is protected by copyright. All rights reserved

Who Feels Safe? Uncertain Futures and Enduring Aspirations in Italy

ABSTRACT In an attempt of going beyond a simple opposition between those conceived as agents and those seen as subjects of disciplinary power, this article engages with a reflection on differential states of precariousness and (un)safety, which involve both ‘forced migrants’ and ‘citizens’. Drawing on ethnographic research in Milan (Italy), I outline some recent institutional changes in the Italian asylum system, which led to the political abandonment of refugees in situations of increasing marginalisation, but also to the layoff of several frontline asylum workers, who were often young people hit by the consequences of economic recession. Through the words and biographical trajectories of three young women (two asylum workers and one refugee), I trace the emergence of contested temporal and work experiences, marked by widespread feelings of uncertainty and devaluation. I approach empirically the idea of (un)safety as a material and bodily condition and as an emotional state, directly linked to the perceived possibility of being able to orient oneself towards the future. By zooming in on differential experiences of (un)safety and precariousness – but also on enduring aspirations – I aim at documenting the material and affective entanglements of acts of government, as well as their inherent potential for empowerment and transformation.

Between forests and coasts: Fishworkers on the move in India

AbstractThe Covid‐19 lockdown in India in March 2020 revealed the presence of Adivasi communities in the marine fishing industry of Goa, a coastal state in India. While the migration for work of Adivasi communities from the central regions of the country is well recorded, their movement across geographies of the forest and the coast is relatively unknown. Working with initial data collected during the lockdown, interviews conducted after the pandemic and using secondary materials, the paper sought to understand the social and material conditions in the forest and the coastal regions that shape this movement. Centring the waged relation of Adivasi workers opened the door to thinking about the marine fishing sector in India as a capitalist industry, while paying attention to social reproduction highlighted how the coastal and forest regions are spatially linked through their movement and labour. This highlights that the coasts and forests are going through distinct processes of capitalist intensification and expansion. Making connections between ecological appropriation, historical processes of resource extraction and marginalization, the paper finds that the extraction of fish resources in Goa is made productive through the hierarchization and differentiation of Adivasi workers. It reveals how the social relations of identity and caste mediate access to and define conditions of work at sea.

SPT approach for assessing mechanical properties of materials

The Round Robin Test of the Small Punch Test (SPT) method represents a critical step in establishing its reliability and applicability for assessing the mechanical properties of materials used in power plants. The mechanical properties of materials, such as strength and deformation characteristics, are of paramount importance in ensuring the structural integrity and safety of power generation facilities. The SPT method, a widely adopted in-situ testing technique, holds promise as a cost-effective means of evaluating these properties. However, its precision and consistency in different geological and operational contexts remain subjects of investigation. This study presents the results and findings from a comprehensive Round Robin Test aimed at rigorously assessing the SPT method's performance and suitability for characterizing materials within power plants. Multiple testing campaigns were conducted across diverse sites and material conditions, encompassing varying geological formations, moisture content, and temperature ranges. The objective was to evaluate the SPT method's repeatability, reproducibility, and accuracy in different operational environments

Ozone-activated lignocellulose films blended with chitosan for edible film production

This work focuses on the influence of ozone pretreatment on the fractionation and solubilization of sugarcane bagasse and soda bagasse pulp fibers in sodium hydroxide/urea solution, as well as the application of regenerated cellulose for producing edible films. The methodology involved pretreating lignocelluloses with ozone for 20 to 120 min before dissolving in sodium hydroxide/urea solution. The influence of the pretreatment conditions on cellulose dissolution yield was investigated. Regenerated cellulose films were then formed, with and without the addition of 2 % chitosan. Mechanical, physical, structural, thermal, and antimicrobial attributes were determined as a function of ozonation conditions of raw materials and chitosan content. The findings exhibited positive effects of short ozonation on enhancing mechanical strength, cohesion, and hydrophobicity. The prolonged ozonation of 120 min demonstrated optimal improvements in continuity, swelling, and antibacterial resistance of obtained films. Incorporating chitosan enhanced tensile performance, stiffness, and vapor barriers but increased moisture absorption. Tailoring the activation of biomass through ozone pretreatment and chitosan addition resulted in renewable films with adjustable properties to meet diverse packaging requirements, particularly for fruit protective coatings, ensuring the preservation of post-harvest quality.

Advancing in Cesium Retention: Application of Magnesium Phosphate Cement Composites.

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water's natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that have varied degrees of toxicity. Radiation from Cs isotopes, which are common components of radioactive waste and are known for their long half-lives (30 years), which are longer than the natural decay processes, is a major source of contamination. Adsorption is a commonly used technique for reducing this kind of contamination, and zeolite chabazite has been chosen as the best adsorbent for cesium in this particular situation. The purpose of this research is to investigate a composite material based on magnesium phosphate cement (MPC). Magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4), and properly selected retarders are used to create the MPC. The optimal conditions for this composite material are investigated through the utilization of X-ray diffraction, scanning electron microscopy, BET surface area analysis, and atomic absorption spectroscopy. The principal aim is to enable innovations in the elimination of radioactive waste-contaminated water using effective cesium removal. The most promising results were obtained by using KH2PO4 as an acid, and MgO as a base, and aiming for an M/P ratio of two or four. Furthermore, we chose zeolite chabazite as a crucial component. The best adsorption abilities for Cs were found at Qads = 106.997 mg/g for S2 and Qads = 122.108 mg/g for S1. As a result, zeolite is an eco-friendly material that is a potential usage option, with many benefits, such as low prices, stability, and ease of regeneration and use.

Mining Charity

Scalding water, plummeting cage elevators, cave-ins, fiery explosions, toxic air. These were among the many hazards of silver ore mining on Nevada’s Comstock Lode in the late 1800s. This article explores the nature of silver mining society in the 1860s and 1870s, focusing on the dangerous conditions in which miners worked in the mineshafts that ran beneath the communities of Virginia City and Gold Hill, Nevada. The material culture and conditions of mining, the article argues, were central to determining the community’s needs and the charitable efforts mounted to address them. Philanthropic work and fundraising for a diverse set of causes—from attending to individuals’ needs to building a hospital to running an orphanage—shaped residents’ social and cultural lives, as well as the built environment in which they lived.

Surface engineering of aerospace aluminium alloys: Understanding alloying effects on chemical pre-treatment and sol-gel coating adhesion

The sol–gel process is a chemical surface preparation method based on hydrolysis and polycondensation reactions for enhanced adhesion for metallic substrates in adhesive bonding and coating applications. This paper describes an investigation into the effect of the microstructural complexity of two commonly used aerospace aluminium alloys (AAs) 2024-T3 and 7075-T6, on the response to different surface pre-treatments before deposition of the sol-gel coating and subsequent adhesive bonding.Different surface pre-treatments, including two abrasive treatments and three chemical surface pre-treatments were used, and their effect on surface chemistry, wettability and roughness was assessed. Surfaces were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, profilometry and static contact angles. A hybrid silane sol-gel film was deposited on the differently pre-treated aluminium alloys, an epoxy adhesive was applied and the adhesion properties were evaluated using pull-off testing. The role of the altered physicochemical properties of the pre-treated surfaces was related to the adhesion strength of the sol–gel reinforced epoxy/aluminium interfaces.The microstructural complexity of the aerospace alloys caused non-uniform responses to the pre-treatments, proving the importance of compatibility between material and treatment conditions. Statistical analysis revealed that, despite that overall higher adhesion values were obtained on rougher surfaces, only a strong correlation exists between the surface hydroxyl fraction and adhesion strength. The relation of roughness and water contact angle to interfacial adhesion was found to be non-significant.The findings of this study underscore the critical role of surface pre-treatments and their impact on adhesion strength in aerospace aluminium alloys, providing valuable insights for the effective utilization of sol-gel coatings in adhesive bonding and coating processes.

Optimal vector phase-matching conditions in biaxial crystalline materials determined by the extreme surfaces method: the case of orthorhombic crystals

The optimal geometries of vector phase matching are determined for the cases of second harmonic generation, sum frequency generation, and difference frequency generation in a number of orthorhombic nonlinear optical crystals: KTP, KTA, KB5, KNbO3, LBO, CBO, and LRB4. The extreme surface method was used to define the wave vector directions of highest possible generation efficiency. As shown, in a significant number of cases vector phase matching ensures higher efficiencies than the scalar one.

Matrix curing and stress field development around fiber during the solvent evaporation-induced repolymerization of recycling composites

When recycling fiber-reinforced composites using depolymerized polymer solutions, oligomers reconnect through covalent bond exchange reactions (BERs), which ultimately forms a crosslinked network with mechanical properties comparable to those of virgin materials. This process offers exciting opportunities for the primary recycling of engineering composites, but it is intricately influenced by a few material and process parameters, such as heating temperature, duration, and fiber volume fractions. These parameters collectively determine the matrix's curing degree and the evolution of stress fields around the fiber, which are significant factors determining the quality and mechanical performance of recycled composites. This study introduces a diffusion-reaction-mechanics finite-element computational model to examine the solvent-induced repolymerization process in recycling composites. The model predicts the matrix curing degree, residual stress development around the fiber, and the composite's mechanical properties, aligning with experimental results. Parametric computational studies are then conducted to assess the influences of temperature, fiber content, solvent diffusivity, and the reactivity of BERs. The objective is to identify material and processing conditions that ensure efficient composite recycling while minimizing the development of residual stress. Overall, this study enhances our understanding of the mechanisms behind composite recycling using organic solvents and provides valuable insights for industrial stakeholders looking to optimize processing conditions and advance the commercialization and widespread adoption of this innovative recycling technique.

EFFECT OF HEAT TREATMENT ON ABRASION WEARRESISTANCE OF STEEL WITH MICRO-ADDITIVES OF BORONAND VANADIUM

This paper presents the results of own research regarding the role of microstructure and mechanical propertiesin the abrasive wear of metallic materials, demonstrated on the example of low-alloyed steel with micro--additives of boron and vanadium. The first section discusses the current knowledge relating to the influenceof microstructure and hardness on tribological conditions of materials. Further sections present the results ofmicrostructure observations performed with light microscopy as well as with scanning electron microscopyand transmission electron microscopy. This research has focused on the material both in the as-deliveredcondition (directly after casting) and after heat treatment, which involved quenching and tempering at threetemperatures: 200, 400, and 600C. The tribological tests were performed with the use of the T-07 tribometer,in the presence of loose #90 electro corundum abrasive particles. The test results have been discussed and anattempt has been made to correlate them with the microstructure and selected mechanical properties. In orderto identify wear mechanisms, the surfaces were visually inspected after the abrasion process. The inspectionresults indicate that the main wear mechanisms were microcutting and microploughing.

Mapping a French Department in the northeastern Amazonia: The 1947 Oyapock mission in a context of Decolonization

This article delves into the interplay between the political, social, and cultural context and the material conditions of governing a cartographic mission within a French territory in the northeastern Amazon. It brings to the fore the collaborative endeavors involving a spectrum of stakeholders, ranging from local knowledge to various institutions, financial and technical resources, and human and logistical support. This research aims to offer an understanding of the cartographic mission during the period of departmentalization, with a specific focus on the situated and context-specific nature of knowledge production. By scrutinizing the fieldwork and the distinct labor regimes of local members of the mission in AEF and French Guiana, along with investigating the intra-imperial circulation of epistemic practices, it examines the colonial integration of cartographers through their trajectories. In a broader context, the article underscores the pivotal role played by geographical knowledge, enriching the landscape of research on the history of cartography during the transformation of the French colonial empire. Employing an approach encompassing material and social dimensions, this study shows the intricacies inherent in colonial cartography and illuminates its implications in the post-World War II era. In doing so, it unlocks fresh avenues for comprehending the geographical and colonial dynamics that characterize this period.

Detection and Analysis of Aircraft Composite Material Structures Using UAV

Pre-flight inspection and maintenance are essential prerequisites for aviation safety. This study focused on developing a real-time monitoring system designed to assess the condition of composite material structures on the exterior of aircraft. Implementing such a system can reduce operational costs, enhance flight safety, and increase aircraft availability. This study aims to detect defects in aircraft fuselages manufactured from composite materials by applying image visual recognition technology. This study integrated a drone and an infrared camera for real-time image transmission to ground stations. MATLAB image analysis software (MATLAB 2020b) was used to analyze infrared (IR) images and detect structural defects in the aircraft’s appearance. This methodology was based on the inspection of damaged engine cowlings. The developed approach compares composite material conditions with known defects before and after repair, considering mechanical performance, defect size, and strength. Simultaneously, tests were conducted on various composite material panels with unknown defects, yielding favorable results. This study underscores an integrated system offering rapid detection, real-time feedback, and analysis, effectively reducing time, and potential hazards associated with high-altitude operations. Furthermore, it addresses blind spots in aircraft inspections, contributing to effective flight safety maintenance.

The Impact of Science and Technology on Careers Industrialization and Modernization in Vietnam

These days, science and technology are the primary drivers of development and the direct producers of the world economy. Every nation must have specific scientific and technical development strategies and programs for each particular period that are appropriate for its circumstances and material conditions, depending on its level of development. Nonetheless, the most noteworthy conclusion to be drawn from the strategies and policies is that every country in the world, from the most developed to the least developed, stated: "The development of science and technology is an important new direction, decisive in the development of the national economy..." As a result, research on the effects of science and technology is crucial for all nations, but Vietnam in particular.

Silicate brick production using anhydrite raw material

Purpose: The aim of this work is to substantiate recycling of anhydrite raw materials for the production of silicate products and the development of methods for preparing source materials, compositions and process modes.Methodology/approach: Selection and research of basic materials, methods of their preparation for the production of silicate products; justification of process methods and assessment of quality parameters of materials with the required properties.Research findings: The possibility of utilizing acid fluoride during the synthesis of calcareous-siliceous binder used to produce silicate bricks during autoclave processing. The obtained sand-lime brick samples possess the following physical and mechanical properties: 1750 to 1900 kg/m3 average density, 10 to 12.5 MPa compressive strength, 16 or 17 % water absorption. The samples meet the requirements for sand-lime bricks, namely strength, density, water absorption and correspond to grades 100 and 125.Practical implications: The process modes of autoclaving are detected and the main operational characteristics of sand-lime brick are determined. Methods proposed for preparing raw materials and process conditions of silicate wall materials allow solving environmental problems and saving natural limestone raw materials.Novelty: Sand-lime brick production is based on anhydrite raw materials; suggested dependencies make it possible to control the composition and properties of silicate materials.

MINDS: Mid-infrared atomic and molecular hydrogen lines in the inner disk around a low-mass star

Understanding the physical conditions of circumstellar material around young stars is crucial to star and planet formation studies. In particular, very low-mass stars ($M_ < 0.2$ M$_ are interesting sources to characterize as they are known to host a diverse population of rocky planets. Molecular and atomic hydrogen lines can probe the properties of the circumstellar gas. This work aims to measure the mass accretion rate, the accretion luminosity, and more generally the physical conditions of the warm emitting gas in the inner disk of the very low-mass star 2MASS-J16053215-1933159. We investigate the source mid-infrared spectrum for atomic and molecular hydrogen line emission. We present the full James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) spectrum of the protoplanetary disk around the very low-mass star 2MASS-J16053215-1933159 from the MINDS GTO program, previously shown to be abundant in hydrocarbon molecules. We analyzed the atomic and molecular hydrogen lines in this source by fitting one or multiple Gaussian profiles. We then built a rotational diagram for the H$_2$ lines to constrain the rotational temperature and column density of the gas. Finally, we compared the observed atomic line fluxes to predictions from two standard emission models. We identify five molecular hydrogen pure rotational lines and 16 atomic hydrogen recombination lines in the 5 to 20 mu m spectral range. The spectrum indicates optically thin emission for both species. We use the molecular hydrogen lines to constrain the mass and temperature of the warm emitting gas. We derive a total gas mass of only $2.3 $ M$_ Jup $ and a temperature of 635 K for the warm H$_2$ gas component located in the very inner disk ($r < 0.033$ au), which only accounts for a small fraction of the upper limit for the disk mass from continuum observations (0.2 M$_ Jup $). The HI (7-6) recombination line is used to measure the mass accretion rate ($4.0 $ M$_ $) and luminosity ($3.1 $ L$_ onto the central source. This line falls close to the HI (11-8) line, however at the spectral resolution of JWST MIRI we managed to measure both separately. Previous studies based on Spitzer have measured the combined flux of both lines to measure accretion rates. HI recombination lines can also be used to derive the physical properties of the gas using atomic recombination models. The model predictions of the atomic line relative intensities constrain the atomic hydrogen density to about $ cm$^ $ and temperatures up to 5\,000 K. The JWST-MIRI MRS observations for the very low-mass star 2MASS-J16053215-1933159 reveal a large number of emission lines, many originating from atomic and molecular hydrogen because we are able to look into the disk warm molecular layer. Their analysis constrains the physical properties of the emitting gas and showcases the potential of JWST to deepen our understanding of the physical and chemical structure of protoplanetary disks.

A sequential bioconversion-purification process to produce high purity xylo-oligosaccharides (XOS) from Nothophagus pumilio sawdust wastes

Xylo-oligosaccharide (XOS) production from lignocellulosic biomass (LCB) is an ongoing technology in which the best raw material, catalyst, and reaction conditions remain unclear. This study proposed a three-step sequential operation to produce prebiotic Xylo-oligosaccharide (XOS) from lignocellulosic biomass (LCB) Nothophagus pumillio sawdust. First, a commercial (Enzeco Xylanase S) and recombinant (GtXyl10A) xylanase were evaluated in XOS production from pre-extracted xylan. Then, the effect of auxiliary enzyme addition (α-glucuronidase) was evaluated in xylan hydrolysis, and finally, XOS were purified by three steps of membrane filtrations: an ultrafiltration (UF) followed by two nanofiltrations (NF). From the above, XOS production yield reach 333 [mgxos∙gxylan−1] of highly purified XOS (95 %) when the process was carried out without auxiliary enzyme addition and 473 [mgxos∙gxylan−1] of 96 % purified XOS when auxiliary enzyme was added, resulting in an improvement of the XOS production yield in 42 %.This shows the feasibility to produce high purity prebiotics from sawdust wastes of the forestry industry.

Determinants of Female Employee Well-being: Interplay of Personal Agency, Societal Norms, and Organizational Contexts

Drawing from a qualitative methodology, this study intricately examines the determinants of well-being within the framework of work and non-work domains. Through four detailed case studies, we unravel how individuals' experiences within their professional roles, embedded in various organizational settings, influence their well-being. Central to our analysis is the understanding that individual perceptions of well-being, while navigating work and non-work domains, are intimately intertwined with larger social structures, historical trajectories, and material conditions. The insights derived from these cases illuminate the intricate relationship between personal agency, societal norms, organizational influences, and well-being. Key findings highlight the significance of role flexibility, life stage influences, and specific life circumstances (e.g., single parenthood, spiritual engagement) as determinants of well-being. By providing a comprehensive understanding of the multifaceted determinants of well-being, this research offers valuable insights for organizational practices, policy-making, and individual well-being strategies.