Performance Assessment of Plant-Produced Warm Recycled Mixtures for Open-Graded Wearing Courses

Author(s):  
Francesca Frigio ◽  
Arianna Stimilli ◽  
Amedeo Virgili ◽  
Francesco Canestrari

Sustainable solutions, such as the combination of reclaimed asphalt pavement (RAP) as a partial substitution of virgin materials and warm-mix asphalt (WMA) additives to decrease production temperatures, represent the new research frontier in the asphalt industry. Specific investigations must evaluate the consequences of recycled WMA performance, especially in the case of open-graded (OG) mixtures, given that lower production temperatures can affect the adhesion properties and durability of those materials. This paper describes an experimental effort that involved OG mixtures produced in plant at warm temperatures (130°C) with two WMA chemical additives characterized by different compositions. In addition, an equivalent mixture (used as a control for comparison purposes) was produced at standard temperatures. Each material was prepared with a polymer-modified binder and 15% RAP. The main objective of the study was to characterize volumetric and mechanical properties of the investigated mixtures with particular attention paid to compactability aptitude and durability. To this end, gyratory-compacted specimens were subjected to several laboratory tests after dry and wet conditioning (i.e., indirect tensile strength, Cantabro test, semicircular bending, and repeated indirect tensile loading). Moreover, plant production of the investigated mixtures made it possible to evaluate the feasibility of large-scale processes. The WMA mixtures showed significant water susceptibility, although they guaranteed good compactability and satisfied mechanical acceptance requirements and international recommendations for raveling resistance in dry conditions. The chemical composition of the WMA additives was found essential to reduce the water damage. Surfactants and adhesion enhancers included within one of the investigated WMA additives ensured better water resistance than the other additive classified as a viscous regulator.

Author(s):  
Ron Avi Astor ◽  
Rami Benbenisthty

Since 2005, the bullying, school violence, and school safety literatures have expanded dramatically in content, disciplines, and empirical studies. However, with this massive expansion of research, there is also a surprising lack of theoretical and empirical direction to guide efforts on how to advance our basic science and practical applications of this growing scientific area of interest. Parallel to this surge in interest, cultural norms, media coverage, and policies to address school safety and bullying have evolved at a remarkably quick pace over the past 13 years. For example, behaviors and populations that just a decade ago were not included in the school violence, bullying, and school safety discourse are now accepted areas of inquiry. These include, for instance, cyberbullying, sexting, social media shaming, teacher–student and student–teacher bullying, sexual harassment and assault, homicide, and suicide. Populations in schools not previously explored, such as lesbian, gay, bisexual, transgender, and queer students and educators and military- and veteran-connected students, become the foci of new research, policies, and programs. As a result, all US states and most industrialized countries now have a complex quilt of new school safety and bullying legislation and policies. Large-scale research and intervention funding programs are often linked to these policies. This book suggests an empirically driven unifying model that brings together these previously distinct literatures. This book presents an ecological model of school violence, bullying, and safety in evolving contexts that integrates all we have learned in the 13 years, and suggests ways to move forward.


2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Sara Benyakhlef ◽  
Ahmed Al Mers ◽  
Ossama Merroun ◽  
Abdelfattah Bouatem ◽  
Hamid Ajdad ◽  
...  

Reducing levelized electricity costs of concentrated solar power (CSP) plants can be of great potential in accelerating the market penetration of these sustainable technologies. Linear Fresnel reflectors (LFRs) are one of these CSP technologies that may potentially contribute to such cost reduction. However, due to very little previous research, LFRs are considered as a low efficiency technology. In this type of solar collectors, there is a variety of design approaches when it comes to optimizing such systems. The present paper aims to tackle a new research axis based on variability study of heliostat curvature as an approach for optimizing small and large-scale LFRs. Numerical investigations based on a ray tracing model have demonstrated that LFR constructors should adopt a uniform curvature for small-scale LFRs and a variable curvature per row for large-scale LFRs. Better optical performances were obtained for LFRs regarding these adopted curvature types. An optimization approach based on the use of uniform heliostat curvature for small-scale LFRs has led to a system cost reduction by means of reducing its receiver surface and height.


2013 ◽  
Vol 680 ◽  
pp. 534-539
Author(s):  
Wei Feng Ma

With the rapid expansion of the campus scale and the increasing of the geographically dispersed campus, how to adopt new theory, new method and new technology to realize the equipment optimized assignment and the information management is a new research challenge. It is the key to safeguard the national fund to use reasonably, and to speed up the development of education healthily. Through analyzing the domestic and foreign related research works, the paper proposed that it can take use of the spatial data expression and analysis with Geographic Information System (GIS) to realize the large-scale and inter-campuses equipment optimized assignment and information management. It discussed the mathematics model and the system architecture. Moreover, the paper described the key implementation technology in great detail such as spatial data mapping with MapInfo professional 9 and the development of WebGIS functions with MapXtreme. The results show that the solution is feasible and effective.


2016 ◽  
Vol 27 (1) ◽  
pp. 15-21 ◽  
Author(s):  
M Kumaresan

Purpose – The purpose of this paper is to extract the eco-friendly natural dye obtained from the flower of Spathodea campanulata and apply on silk fabric using combination of mordants. The fastness properties of the flower of Spathodea campanulata dyed silk fabric have been studied using different combination (1:3, 1:1 and 3:1) of various mordants, such as myrobolan: nickel sulphate, myrobolan: aluminium sulphate, myrobolan: potassium dichromate, myrobolan: ferrous sulphate and myrobolan: stannous chloride. The wash, rub, light and perspiration fastness of the dyed samples have been evaluated. Design/methodology/approach – For dyeing there are three methods are used. They are Pre mordanting, Simultaneous mordanting and Post mordanting methods. Dyed silk materials are tested by using wash fastness, rub fastness, light and perspiration fastness methods. Findings – It is found that Spathodea campanulata dye can be successfully used for the dyeing of silk to obtain a wide range colours by using various combinations of mordants. With regards to colour fastness, test samples exhibit excellent fastness to washing, rubbing, except for pre-mordanting using myrobolan: potassium dichromate combination; and good to excellent fastness to perspiration in both acidic and alkaline media. Originality/value – Availability of literature related to this work is not available. The study of combination of mordants of this natural dye on silk is a new research work and the large scale preparation is definitely very useful to the society.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Lukose ◽  
M. Lisker ◽  
F. Akhtar ◽  
M. Fraschke ◽  
T. Grabolla ◽  
...  

AbstractOne of the limiting factors of graphene integration into electronic, photonic, or sensing devices is the unavailability of large-scale graphene directly grown on the isolators. Therefore, it is necessary to transfer graphene from the donor growth wafers onto the isolating target wafers. In the present research, graphene was transferred from the chemical vapor deposited 200 mm Germanium/Silicon (Ge/Si) wafers onto isolating (SiO2/Si and Si3N4/Si) wafers by electrochemical delamination procedure, employing poly(methylmethacrylate) as an intermediate support layer. In order to influence the adhesion properties of graphene, the wettability properties of the target substrates were investigated in this study. To increase the adhesion of the graphene on the isolating surfaces, they were pre-treated with oxygen plasma prior the transfer process of graphene. The wetting contact angle measurements revealed the increase of the hydrophilicity after surface interaction with oxygen plasma, leading to improved adhesion of the graphene on 200 mm target wafers and possible proof-of-concept development of graphene-based devices in standard Si technologies.


Author(s):  
Jessica Bell ◽  
Megan Prictor ◽  
Lauren Davenport ◽  
Lynda O’Brien ◽  
Melissa Wake

‘Digital Mega-Studies’ are entirely or extensively digitised, longitudinal, population-scale initiatives, collecting, storing, and making available individual-level research data of different types and from multiple sources, shaped by technological developments and unforeseeable risks over time. The Australian ‘Gen V’ project exemplifies this new research paradigm. In 2019, we undertook a multidisciplinary, multi-stakeholder process to map Digital Mega-Studies’ key characteristics, legal and governance challenges and likely solutions. We conducted large and small group processes within a one-day symposium and directed online synthesis and group prioritisation over subsequent weeks. We present our methods (including elicitation, affinity mapping and prioritisation processes) and findings, proposing six priority governance principles across three areas—data, participation, trust—to support future high-quality, large-scale digital research in health.


2018 ◽  
Vol 43 (1) ◽  
pp. 245-265 ◽  
Author(s):  
Jon Barnett ◽  
W. Neil Adger

Research on environmental change has often focused on changes in population as a significant driver of unsustainability and environmental degradation. Demographic pessimism and limited engagement with demographic realities underpin many arguments concerning limits to growth, environmental refugees, and environment-related conflicts. Re-engagement between demographic and environmental sciences has led to greater understanding of the interactions between the size, composition, and distribution of populations and exposure to environmental risks and contributions to environmental burdens. We review the results of this renewed and far more nuanced research frontier, focusing in particular on the way demographic trends affect exposure, sensitivity, and adaptation to environmental change. New research has explained how migration systems interact with environmental challenges in individual decisions and in globally aggregate flows. Here we integrate analysis on demographic and environmental risks that often share a root cause in limited social freedoms and opportunities. We argue for a capabilities approach to promoting sustainable solutions for a more mobile world.


2011 ◽  
Vol 17 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Amir Kavussi ◽  
Leila Hashemian

One of the main advantages of warm mix asphalt (WMA) used as an alternative to conventional hot mix asphalt (HMA), is to reduce mixing and compaction temperatures. This laboratory study was conducted with the aim of determining physical properties of WMA mixes produced using foam bitumen technology (WMA–Foam), while applying different mixing and compaction temperatures. The effect of laboratory compaction method on mix properties was also investigated. WMA–Foam mixes were produced, adding a soft bitumen to coarse aggregate particles at the first stage, then a hard bitumen, transformed into foam bitumen using a laboratory foam making device, was directly added to aggregates at the next stage. Compaction was performed separately applying both Marshall and gyratory compactors (GC) at different temperatures. Marshall Stability and void contents of the samples were determined as two major parameters for characterizing WMA–Foam mixes. Moisture susceptibility and rutting potential of WMA–Foam samples were evaluated using indirect tensile strength (ITS) and wheel tracking tests. In addition, separate samples were prepared, in which hydrated lime powder was added as an anti-stripping agent to improve adhesion properties of the mixes. Comparing the results of WMA–Foam mixes with control HMA of the same content, resulted in mixes with similar properties of the control HMA, with appreciably lower production and compaction temperatures of the former. It was also resulted that mixes compacted with gyratory compactor were less sensitive to temperature variations than those compacted with Marshall Hammer. Santrauka Pagrindinis šiltai maišyto asfalto mišinių privalumas, lyginant su įprastiniais karštai maišyto asfalto mišiniais, yra galimybė sumažinti asfalto mišinio maišymo ir tankinimo temperatūras. Šio laboratorinio tyrimo tikslas – nustatyti šiltai maišyto asfalto mišinių, gaminamų pagal putoto bitumo technologiją (WMA-Foam), fizines savybes taikant skirtingas maišymo ir tankinimo temperatūras. Taip pat buvo tirtas skirtingų laboratorinių tankinimo metodų poreikis asfalto mišinio savybėms. WMA-Foam technologijos mišiniai gaminti pirmame etape į stambiąsias mineralines medžiagas dedant minkštąjį bitumą, o kitame etape – kietajį bitumą specialiu laboratoriniu putojimo įrenginiu pavertus putotu bitumu dedant į pirmame etape paruoštas mineralines medžiagas. Tankinta atskirai Maršalo plūktuvu ir giratoriaus presu skirtingose mišinio temperatūrose. Maršalo bandinių pastovumas ir oro tuštumų skaičius buvo nustatyti kaip du pagrindiniai WMA-Foamtechnologijos mišinius charakterizuojantys parametrai. WMA-Foam technologijos bandinių jautrumas vandeniui ir atsparumas provėžų susidarymui buvo vertinti pagal netiesioginio tempimo jėgos ir rato riedėjimo vėžės nustatymo bandymus. Keletas bandinių papildomai buvo pagaminti su gesintosiomis kalkėmis, t. y. asfalto mišinio sukibimą gerinančiu priedu. Lyginant WMA-Foam technologijos ir karštai maišyto asfalto mišinių bandymų rezultatus nustatyta, kad identiškos sudėties WMA-Foam technologijos mišinių savybės yra panašios į karštai maišyto asfalto mišinių savybes, tačiau jos pasiekiamos pastebimai žemesnėse maišymo ir tankinimo temperatūrose. Taip pat nustatyta, kad asfalto mišinio bandiniai, pagaminti giratoriaus presu, buvo ne tokie jautrūs gamybos temperatūros kitimui, lyginant su bandiniais, pagamintais Maršalo plūktuvu.


Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
Claudia Simões-Gurgel ◽  
Tatiana Carvalho de Castro ◽  
Cátia Henriques Callado ◽  
Lívia da Silva Cordeiro ◽  
Norma Albarello

Abstract In vitro culture techniques are recognized as efficient strategies for large-scale plant production, as well as providing alternatives for plant conservation. In this study the micropropagation of Tarenaya rosea was established using petiole and foliar blade segments cultivated on MS medium with 6-benzyladenine (BA) and/or 6-furfurylaminopurine (KIN). The regeneration rate from explants was evaluated after 30-days in culture, as well as the proliferation rate from explant-derived shoots, reached after four subcultures performed at 30-days in culture. In vitro propagation occurred by both direct (DO) and indirect (IO) organogenesis. The highest regeneration rates by DO (50% to 100%) were reached on media containing only BA, while morphogenic calluses (IO) were mainly formed with BA+KIN. Explants on media with BA showed the presence of small black nodules on their surface, and histological analysis revealed the presence of trichomes with anthocyanin content. Elongation and rooting were reached on growth regulator-free MS. Acclimatization rates around 80% were achieved and the in vitro-regenerated plants were successfully maintained under field conditions. Results show significant morphogenetic potential of T. rosea from leaf explants, mainly when cultivated in the presence of 4.4 µM BA, providing a new alternative source of plant material for biotechnological and in vitro conservation studies.


Tapestry, the most costly and coveted art form in Renaissance and Baroque Europe, has long fascinated scholars. In the 19th and early 20th centuries, researchers delved into archival sources and studied extant tapestries to produce sweeping introductions to the medium. The study of tapestry, however, fell outside mainstream art history, with tapestry too often seen as a less important “decorative art” rather than a “fine art.” , Also, tapestry did not fit easily into an art history that prioritized one master, as the making of a set of large-scale tapestries required a team of collaborators, including the designer, cartoon painters, and weavers, as well as a producer/entrepreneur and, often, a patron. Scholarship on European tapestries in the Early Modern period, nevertheless, flourished. By the late 20th century art historians turned attention to the “decorative arts” and tapestry specialists produced exciting new research illuminating aspects of design, production, and patronage, as well as tapestry’s crucial role in the larger narrative of art and cultural history. In 2002, the Metropolitan Museum of Art’s landmark exhibition and catalogue, Tapestry in the Renaissance: Art and Magnificence, spotlighted the art form, introduced it to a broad audience, and brought new understanding of tapestry as art. A sequel, the Met’s 2007 exhibition and catalogue, Tapestry in the Baroque: Threads of Splendor, followed. Other major museums presented ambitious exhibitions, accompanied by catalogues with substantial new research. In addition, from the late 20th century, institutions have produced complete catalogues of their extraordinary European tapestry holdings, among them: the Metropolitan Museum of Art in New York; the Patrimonio Nacional in Spain; the Rijksmuseum in Amsterdam; the Art Institute of Chicago; and the Burrell Collection in Glasgow. At the same time, articles and books exploring specific designs, designers, producers, and patrons appeared, with some monographs published in the dedicated series, Studies in Western Tapestry, edited by leading scholars Guy Delmarcel and Koenraad Brosens, and produced by Brepols. Tapestry research has often focused on the works of well-known designers and their exceptionally innovative work, such as the artists Raphael (b. 1483–d. 1520) or Peter Paul Rubens (b. 1577–d. 1640). High-quality production at major centers, including Brussels or at the Gobelins Manufactory in France, has also captured scholars’ attention, as have important patrons, among them Henry VIII of England (b. 1491–d. 1547) or Louis XIV of France (b. 1638–d. 1715). Newer directions for research include the contributions of women as weavers and entrepreneurs, the practice of reweaving designs, and the international reach and appeal of Renaissance and Baroque tapestry beyond Europe.


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