scholarly journals Selection of Additives and Fibers for Improving the Mechanical and Safety Properties of Porous Concrete Pavements through Multi-Criteria Decision-Making Analysis

2020 ◽  
Vol 12 (6) ◽  
pp. 2392 ◽  
Author(s):  
Eduardo-Javier Elizondo-Martínez ◽  
Valerio-Carlos Andrés-Valeri ◽  
Jorge Rodríguez-Hernández ◽  
Cesare Sangiorgi
Keyword(s):  
Mechanical Strength ◽  
Structural Integrity ◽  
Concrete Pavements ◽  
Safety Properties ◽  
Light Traffic ◽  
Infiltration Capacity ◽  
Porous Concrete ◽  
Indirect Tensile ◽  
The Common ◽  
Selection Of

Despite the number of environmental advantages that porous concrete (PC) pavements can provide, they are mainly used in light-traffic roads, parking lots and sidewalks due to their low mechanical strength. This research focuses on the common additives employed in PC pavements, according to a literature review, with the aim of increasing their mechanical strength while maintaining an acceptable infiltration capacity. The results demonstrated that the combination of superplasticizers and air-entraining additives can provide indirect tensile strength values over 2.50 MPa, with an infiltration capacity over 0.40 cm/s. In addition, polypropylene fibers were seen to provide very good safety properties, preserving some structural integrity in the case of failure. All mixtures studied obtained outstanding skid resistance results under both dry and wet conditions.

scholarly journals Characterization of the Infiltration Capacity of Porous Concrete Pavements with Low Constant Head Permeability Tests

Water ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 480 ◽  
Author(s):  
Valerio Andres-Valeri ◽  
Luis Juli-Gandara ◽  
Daniel Jato-Espino ◽  
Jorge Rodriguez-Hernandez
Keyword(s):  
Concrete Pavements ◽  
Infiltration Capacity ◽  
Porous Concrete ◽  
Constant Head

scholarly journals Physical and Mechanical Characterization of Sustainable and Innovative Porous Concrete for Urban Pavements Containing Metakaolin

2020 ◽  
Vol 12 (10) ◽  
pp. 4243 ◽  
Author(s):  
Eduardo-Javier Elizondo-Martinez ◽  
Piergiorgio Tataranni ◽  
Jorge Rodriguez-Hernandez ◽  
Daniel Castro-Fresno
Keyword(s):  
Tensile Strength ◽  
Environmental Impacts ◽  
Indirect Tensile Strength ◽  
Partial Substitution ◽  
Concrete Pavements ◽  
Suitable Alternative ◽  
Porous Concrete ◽  
Concrete Mixtures ◽  
Alternative Materials ◽  
Indirect Tensile

Alternative materials to replace cement in pavements have recently been widely studied with the purpose of decreasing the environmental impacts that the construction industry generates. In this context, the implementation of sustainable urban drainage systems has grown, especially with porous pavements, with the intention to reduce water and environmental impacts. In the present investigation, the addition of alternative materials to minimize the use of cement in porous concrete pavements is evaluated. Starting from a partial substitution of Portland cement with metakaolin, experimental geopolymer concretes were produced with metakaolin and waste basalt powder according to several dosages. Two sets of mixtures were analyzed to evaluate the Porous Concrete Design (PCD) methodology for porous concrete mixtures with alternative materials. A deep analysis was proposed for the evaluation of the mechanical and volumetric properties of the mixtures. Results demonstrated that replacing 5% of cement with metakaolin can increase both permeability and indirect tensile strength. Geopolymer mixtures can achieve permeability significantly higher than the traditional porous concrete, but this decreases their indirect tensile strength. However, considering the promising results, an adjustment in the mix design of the geopolymer mixtures could increase their mechanical properties without negatively affecting the porosity, making these materials a suitable alternative to traditional porous cement concrete, and a solution to be used in urban pavements.

scholarly journals A quantitative assessment of the mechanical strength of the polar pteropod Limacina helicina antarctica shell

2013 ◽  
Vol 70 (7) ◽  
pp. 1499-1505 ◽  
Author(s):  
Clara M. H. Teniswood ◽  
Donna Roberts ◽  
William R. Howard ◽  
Jodie E. Bradby
Keyword(s):  
Southern Ocean ◽  
Mechanical Strength ◽  
Quantitative Data ◽  
Quantitative Assessment ◽  
Structural Integrity ◽  
Morphological Studies ◽  
Average Hardness ◽  
Limacina Helicina ◽  
The Common ◽  
Ocean Carbon

Abstract Teniswood, C. M. H., Roberts, D., Howard, W. R., and Bradby, J. E. 2013. A quantitative assessment of the mechanical strength of the polar pteropod Limacina helicina antarctica shell. – ICES Journal of Marine Science, 70: . This work directly measures the mechanical properties of pteropod shells collected from the Southern Ocean on the 2007 midsummer Subantarctic Zone Sensitivity to Environmental Change (SAZ-Sense) voyage. Shells from the common Southern Ocean pteropod Limacina helicina antarctica were subjected to mechanical analyses in combination with detailed morphological studies. Average hardness and modulus of 2.30 ± 0.07 GPa and 45.27 ± 0.91 GPa, respectively were calculated from several hundred nanoindentation measurements taken from multiple positions across twelve shells of the same species collected under identical conditions. Quantitative data such as these are critical to establish a reference point for future comparative studies and to both understand and evaluate the implications of further ocean acidification on the structural integrity of these common polar calcifiers, particularly in light of their role in the Southern Ocean carbon cycle and food web.

scholarly journals Experimental appraisal for characterizing laboratorial and field performance parameters of pervious concrete pavement

2021 ◽  
Vol 21 (2) ◽  
pp. 177-194
Author(s):  
Rafael Batezini ◽  
José Tadeu Balbo ◽  
Liv Haselbach ◽  
Filipe de Oliveira Curvo ◽  
Guilherme Nunes Kalleder ◽  
...  
Keyword(s):  
Field Performance ◽  
Infiltration Rate ◽  
Pervious Concrete ◽  
Concrete Pavements ◽  
Light Traffic ◽  
Conventional Concrete ◽  
Concrete Layer ◽  
Mechanistic Analysis ◽  
Significant Difference ◽  
Indirect Tensile

Abstract Loratorial tests with pervious concrete comprised porosity and hydraulic conductivity as well as mechanical parameters as compressive, indirect tensile and bending strengths besides assessing its static and dynamic elasticity moduli. Later, a pervious sidewalk area of 1.0 x 8.65 square meters was built in order to determine the variation of the infiltration rate along time; over such experimental sidewalk, impact deflection tests performed allowed to assess back calculated moduli of the pervious concrete layer, resulting 33% to 13% lower than conventional concretes. A mechanistic analysis allowed to estimate the required thickness of concrete for heavy- and light-traffic areas. Tests disclosed no significant difference among the different concrete mixes, with 25% porosity and 0,1 cm/s permeability. Initial sidewalk infiltration rate of 0.5 cm/s dropped 50% four months after construction. It was verified that pervious concrete thicknesses for trucks and buses use are far higher than conventional concrete pavements.

Identification of Possible High Integrity Containers for Low-Level Nuclear Waste Disposal

1981 ◽  
Vol 6 ◽  
Author(s):  
Jeffrey D. Williams
Keyword(s):  
South Carolina ◽  
Structural Integrity ◽  
Exchange Resin ◽  
Ion Exchange Resin ◽  
Economic Factors ◽  
Burial Site ◽  
Low Level ◽  
High Integrity ◽  
Low Level Radioactive Waste ◽  
Selection Of

ABSTRACTIncreased concern by the State of South Carolina over the condition and capacity of the low-level radioactive waste burial site at Barnwell has prompted them to promulgate new regulations on waste burial containers. As of September 30, 1981, ion exchange resin and filter media waste with an activity of 1 μCi/cc or greater and with isotopes with halflives greater than five years disposed at Barnwell shall be solidified or confined in a “high integrity container”. The materials and designs of these containers are required to provide waste isolation from the environment for a period of 300 years and provide the structural integrity specified in 49 CFR 173.398(b). HITTMAN has been active in the design and development of containers suitable for this purpose with this paper detailing the analyses involved. Material selections were limited to stainless steel, fiberglass, and polyethylenes. Structural concerns focused on overpressure requirements, drop-testing requirements, and lifting capabilities. With a lifetime dose of up to 108 rads, the possibilities of radiation damage were considered. Preliminary selection of polyethylene was based on satisfactory resolution of these issues and economic factors.

Kesulitan Mahasiswa Pembelajar Pemula Bahasa Perancis dalam Memahami Gramatika

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 354
Author(s):  
Ferli Hasanah
Keyword(s):  
French Literature ◽  
French Language ◽  
First Year ◽  
The Common ◽  
French Grammar ◽  
Bahasa Indonesia ◽  
Selection Of

ABSTRAKGramatika pada setiap bahasa memiliki kekhasannya masing-masing.Mahasiswa Program Studi Sastra Perancis tahun pertama sebagai pembelajar pemulasering mengalami kesulitan dalam memahami gramatika bahasa. Kesulitan mereka tidakterlepas dari perbedaan-perbedaan mendasar pada struktur bahasa Indonesia sebagaibahasa ibu mereka dan bahasa Perancis yang tengah dipelajari. Penelitian ini dilaksanakandengan tujuan untuk mengetahui hambatan yang dimiliki mahasiswa pembelajar pemuladi Program Studi Sastra Perancis Universitas Padjadjaran dalam memahami gramatikabahasa Perancis. Metode yang digunakan dalam penelitian ini adalah metode simak dancatat. Hasil analisis ini menunjukkan bahwa kesalahan-kesalahan yang umum dilakukanpembelajar pemula ada pada penggunaan accent, konjugasi verba, partikel défini maupunindéfini, accord penanda feminin atau jamak, serta pemilihan preposisi.Kata kunci: gramatika, bahasa Perancis, konjugasiABST RACTThe grammar in every language has its own particularities. French literaturestudents in the first year as a beginner learners often have problem in understandingFrench grammar which is frequently considered difficult. Their struggle is inseparablefrom the fundamental differences between Indonesian structure as their mother tongueand the French language which being studied. This research aims to know the obstaclesof the students of beginner learners in the French Literature of Padjadjaran university inunderstanding the basic French grammar. The method used in this research is referringand taking notes method. The results of the analysis shows that the common mistakes oflearners are in the use of accents, verb conjugations, particles défini or indéfini, markeraccord feminine or plural, and the selection of prepositions.Keywords: grammar, French, conjugation

Philosophcal review of h. white̕s tropological theory in the context of the new philosophy of history

2020 ◽  
Vol 3 (152) ◽  
pp. 92-99
Author(s):  
S. M. Geiko ◽  
◽  
O. D. Lauta
Keyword(s):  
Modern Science ◽  
Historical Knowledge ◽  
Text Organization ◽  
The Social ◽  
History Of ◽  
Actual Material ◽  
The Common ◽  
Historical Nature ◽  
Selection Of

The article provides a philosophical analysis of the tropological theory of the history of H. White. The researcher claims that history is a specific kind of literature, and the historical works is the connection of a certain set of research and narrative operations. The first type of operation answers the question of why the event happened this way and not the other. The second operation is the social description, the narrative of events, the intellectual act of organizing the actual material. According to H. White, this is where the set of ideas and preferences of the researcher begin to work, mainly of a literary and historical nature. Explanations are the main mechanism that becomes the common thread of the narrative. The are implemented through using plot (romantic, satire, comic and tragic) and trope systems – the main stylistic forms of text organization (metaphor, metonymy, synecdoche, irony). The latter decisively influenced for result of the work historians. Historiographical style follows the tropological model, the selection of which is determined by the historian’s individual language practice. When the choice is made, the imagination is ready to create a narrative. Therefore, the historical understanding, according to H. White, can only be tropological. H. White proposes a new methodology for historical research. During the discourse, adequate speech is created to analyze historical phenomena, which the philosopher defines as prefigurative tropological movement. This is how history is revealed through the art of anthropology. Thus, H. White’s tropical history theory offers modern science f meaningful and metatheoretically significant. The structure of concepts on which the classification of historiographical styles can be based and the predictive function of philosophy regarding historical knowledge can be refined.

Peculiarities of the juvenile period of the native Chechen genotypes of willow leaf pear (Pyrus salicifolia Pall.)

2020 ◽  
Vol 62 ◽  
pp. 32-38
Author(s):  
E. A. Dolmatov ◽  
R. B. Borzayev ◽  
A. N. Shaipov
Keyword(s):  
Chestnut Soil ◽  
Crop Breeding ◽  
Juvenile Period ◽  
Period 2 ◽  
Russian Research Institute ◽  
The Common ◽  
One Year ◽  
First Time ◽  
Selection Of ◽  
Creative Cooperation

The results of the study of the duration of the juvenile period of indigenous Chechen willow leaf pear genotypes (Pyrus salicifolia Pall.) are given in connection with the acceleration of the breeding process and the use of selected forms in pear breeding for high precocity. The studies were carried out in 2016-2019 at OOO “Orchards of Chechnya” in accordance with the Agreement on creative cooperation with the Russian Research Institute of Fruit Crop Breeding. The work was carried out in accordance with generally accepted programs and methods. The objects of the study were one-year and two-year-old pear seedlings obtained from sowing seeds of selected dwarf and low-growing local Chechen forms of willow pear (P. salicifolia Pall.), laying fruit buds on annual growths and seedlings of Caucasian pear (P. caucasica Fed.), 20 500 pcs. of each specie. The aim of the research was to study the potential of precocity of willow pear seedlings and to reveal of selected forms with the greatest degree of this trait. Stratified seeds were sown in the sowing department of the OOO “Orchards of Chechnya” production nursery in April, 2017. The seedlings were grown according to the common technology in dryland conditions on the plot with chestnut soil. The first fl owering of plants was noted in the spring, 2019. As a result of the research, for the first time on a large number of the experimental material it was found that in the off spring of the indigenous Chechen willow leaf pear genotypes, the selection of a little more than 2% of seedlings with a very short juvenile period (2 years) was possible. They are of great interest in accelerating the breeding process and in the selection of new pear varieties with high precocity. 20 willow leaf pear genotypes were selected for the further use in breeding for high precocity and as sources of the trait of short juvenile period.

scholarly journals Mechanical strength and hydraulic properties of modified porous concrete mixtures

2021 ◽  
Vol 1895 (1) ◽  
pp. 012027
Author(s):  
Hussein J. Almansori ◽  
Adnan Al-Sibahy ◽  
Basim Al-Humeidawi
Keyword(s):  
Mechanical Strength ◽  
Hydraulic Properties ◽  
Porous Concrete ◽  
Concrete Mixtures

scholarly journals Viscoelastometric Testing to Assess Hemostasis of COVID-19: A Systematic Review

2021 ◽  
Vol 10 (8) ◽  
pp. 1740
Author(s):  
Marion Bareille ◽  
Michaël Hardy ◽  
Jonathan Douxfils ◽  
Stéphanie Roullet ◽  
Dominique Lasne ◽  
...  
Keyword(s):  
Systematic Review ◽  
Mechanical Strength ◽  
Small Sample ◽  
The Common ◽  
Small Sample Sizes ◽  
Definition Of ◽  
Reported Data ◽  
Prophylactic Anticoagulation ◽  
The Impact ◽  
Heparin Neutralization

Infection by SARS-CoV-2 is associated with a high risk of thrombosis. The laboratory documentation of hypercoagulability and impaired fibrinolysis remains a challenge. Our aim was to assess the potential usefulness of viscoelastometric testing (VET) to predict thrombotic events in COVID-19 patients according to the literature. We also (i) analyzed the impact of anticoagulation and the methods used to neutralize heparin, (ii) analyzed whether maximal clot mechanical strength brings more information than Clauss fibrinogen, and (iii) critically scrutinized the diagnosis of hypofibrinolysis. We performed a systematic search in PubMed and Scopus databases until December 31st, 2020. VET methods and parameters, and patients’ features and outcomes were extracted. VET was performed for 1063 patients (893 intensive care unit (ICU) and 170 non-ICU, 44 studies). There was extensive heterogeneity concerning study design, VET device used (ROTEM, TEG, Quantra and ClotPro) and reagents (with non-systematic use of heparin neutralization), timing of assay, and definition of hypercoagulable state. Notably, only 4 out of 25 studies using ROTEM reported data with heparinase (HEPTEM). The common findings were increased clot mechanical strength mainly due to excessive fibrinogen component and impaired to absent fibrinolysis, more conspicuous in the presence of an added plasminogen activator. Only 4 studies out of the 16 that addressed the point found an association of VETs with thrombotic events. So-called functional fibrinogen assessed by VETs showed a variable correlation with Clauss fibrinogen. Abnormal VET pattern, often evidenced despite standard prophylactic anticoagulation, tended to normalize after increased dosing. VET studies reported heterogeneity, and small sample sizes do not support an association between the poorly defined prothrombotic phenotype of COVID-19 and thrombotic events.

Sign in / Sign up

Export Citation Format

Share Document