New diphasic insight into the restricted flowability and granular blocking of self-consolidating concrete: Effect of morphological characteristics of coarse aggregate on passing ability of SCC

2021 ◽  
Vol 308 ◽  
pp. 125001
Author(s):  
Masoud Hosseinpoor ◽  
Baba-Issa Ouro Koura ◽  
Ammar Yahia
Keyword(s):  
Coarse Aggregate ◽  
Morphological Characteristics ◽  
Self Consolidating Concrete ◽  
Passing Ability ◽  
Insight Into

scholarly journals Phytophthora Diversity in Pennsylvania Nurseries and Greenhouses Inferred from Clinical Samples Collected over Four Decades

2020 ◽  
Vol 8 (7) ◽  
pp. 1056
Author(s):  
Cody Molnar ◽  
Ekaterina Nikolaeva ◽  
Seonghwan Kim ◽  
Tracey Olson ◽  
Devin Bily ◽  
...  
Keyword(s):  
Plant Species ◽  
Morphological Characteristics ◽  
Phytophthora Species ◽  
Clinical Samples ◽  
Department Of Agriculture ◽  
Distinct Subgroup ◽  
Exotic Pathogens ◽  
Diverse Plant Species ◽  
Insight Into ◽  
Diverse Plant

The increasing movement of exotic pathogens calls for systematic surveillance so that newly introduced pathogens can be recognized and dealt with early. A resource crucial for recognizing such pathogens is knowledge about the spatial and temporal diversity of endemic pathogens. Here, we report an effort to build this resource for Pennsylvania (PA) by characterizing the identity and distribution of Phytophthora species isolated from diverse plant species in PA nurseries and greenhouses. We identified 1137 Phytophthora isolates cultured from clinical samples of >150 plant species submitted to the PA Department of Agriculture for diagnosis from 1975 to 2019 using sequences of one or more loci and morphological characteristics. The three most commonly received plants were Abies, Rhododendron, and Pseudotsuga. Thirty-six Phytophthora species identified represent all clades, except 3 and 10, and included a distinct subgroup of a known species and a prospective new species. Prominent pathogenic species such as P. cactorum, P. cinnamomi, P. nicotianae, P. drechsleri, P. pini, P. plurivora, and P. sp. kelmania have been found consistently since 1975. One isolate cultured from Juniperus horizontalis roots did not correspond to any known species, and several other isolates also show considerable genetic variation from any authentic species or isolate. Some species were isolated from never-before-documented plants, suggesting that their host range is larger than previously thought. This survey only provides a coarse picture of historical patterns of Phytophthora encounters in PA nurseries and greenhouses because the isolation of Phytophthora was not designed for a systematic survey. However, its extensive temporal and plant coverage offers a unique insight into the association of Phytophthora with diverse plants in nurseries and greenhouses.

scholarly journals Influence of coarse aggregate on shear resistance of self-consolidating concrete beams

2017 ◽  
Vol 10 (1) ◽  
pp. 30-40
Author(s):  
G. SAVARIS ◽  
R. C. A. PINTO
Keyword(s):  
Shear Strength ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Concrete Beams ◽  
Shear Resistance ◽  
Self Consolidating Concrete ◽  
Coarse Aggregates ◽  
Lower Shear ◽  
Nominal Size ◽  
High Flowability

Abstract Self-consolidating concrete is characterized by its high flowability, which can be achieved with the addition of superplasticizer and the reduction of the amount and size of coarse aggregates in the concrete mix. This high flowability allows the concrete to properly fill the formwork without any mechanical vibration. The reduction in volume and particle size of the coarse aggregates may result in lower shear strength of beams due to a reduced aggregate interlock. Therefore, an experimental investigation was conducted to evaluate the influence of the reduction in the volume fraction and the nominal size of coarse aggregate on concrete shear strength of self-consolidating beams. Six concrete mixes were produced, four self-consolidating and two conventionally vibrated. A total of 18 beams, with flexural reinforcement but without shear reinforcement were cast. These beams were tested under a four-point loading condition. Their failure modes, cracking patterns and shear resistances were evaluated. The obtained shear resistances were compared to the theoretical values given by the ACI-318 and EC-2 codes. The results demonstrated a lower shear resistance of self-consolidating concrete beams, caused mainly due to the reduced aggregate size.

scholarly journals Insight into Composition of Bioactive Phenolic Compounds in Leaves and Flowers of Green and Purple Basil

Plants ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 22 ◽  
Author(s):  
Bhakti Prinsi ◽  
Silvia Morgutti ◽  
Noemi Negrini ◽  
Franco Faoro ◽  
Luca Espen
Keyword(s):  
Phenolic Acids ◽  
Rosmarinic Acid ◽  
Antioxidant Properties ◽  
Morphological Characteristics ◽  
Ocimum Basilicum ◽  
Ornamental Plant ◽  
Low Degree ◽  
New Knowledge ◽  
Acylated Anthocyanins ◽  
Insight Into

Basil (Ocimum basilicum L.) is a culinary, medicinal, and ornamental plant appreciated for its antioxidant properties, mainly attributed to high content of rosmarinic acid. This species also includes purple varieties, characterized by the accumulation of anthocyanins in leaves and flowers. In this work, we compared the main morphological characteristics, the antioxidant capacity and the chemical composition in leaves, flowers, and corollas of green (‘Italiano Classico’) and purple (‘Red Rubin’ and ‘Dark Opal’) basil varieties. The LC-ESI-MS/MS analysis of individual compounds allowed quantifying 17 (poly)phenolic acids and 18 flavonoids, differently accumulated in leaves and flowers of the three varieties. The study revealed that in addition to rosmarinic acid, basil contains several members of the salvianolic acid family, only scarcely descripted in this species, as well as, especially in flowers, simple phenolic acids, such as 4-hydroxybenzoic acid and salvianic acid A. Moreover, the study revealed that purple leaves mainly contain highly acylated anthocyanins, while purple flowers accumulate anthocyanins with low degree of decoration. Overall, this study provides new biochemical information about the presence of not yet characterized bioactive compounds in basil that could contribute to boosting the use of this crop and to gaining new knowledge about the roles of these compounds in plant physiology.

Correlations between Fresh Properties of Self-Consolidating Concrete Including Palm Oil Fuel Ash

2011 ◽  
Vol 250-253 ◽  
pp. 409-416 ◽  
Author(s):  
Md. Safiuddin ◽  
Md. Abdus Salam ◽  
Mohd Zamin Jumaat
Keyword(s):  
Palm Oil ◽  
Flow Time ◽  
Fresh Properties ◽  
Palm Oil Fuel Ash ◽  
Self Consolidating Concrete ◽  
Slump Flow ◽  
Filling Ability ◽  
Fuel Ash ◽  
Oil Fuel ◽  
Passing Ability

Palm oil fuel ash (POFA) has been used successfully as a supplementary cementing material in various types of concrete. In the present study, self-consolidating concrete (SCC) was produced by using POFA as a partial replacement of ordinary portland cement (OPC). In total, sixteen SCC mixes were prepared by varying water to binder (W/B) ratio, POFA content, and high-range water reducer (HRWR). POFA was used by replacing 0–30% of OPC by weight at the W/B ratios ranging from 0.25 to 0.40. The filling ability, passing ability and segregation resistance of various SCC mixes were investigated. The filling ability was determined with respect to slump flow, 50-cm slump flow time, inverted slump cone flow spread and time, and V-funnel flow time. The passing ability was examined with respect to J-ring flow. In addition, the segregation resistance was assessed with regard to sieve segregation index and column segregation factor. Based on the data obtained, the correlations for the fresh properties of SCC were sought. The experimental findings showed strong correlations between most of the fresh properties of SCC.

scholarly journals Debris-carrying camouflage among diverse lineages of Cretaceous insects

2016 ◽  
Vol 2 (6) ◽  
pp. e1501918 ◽  
Author(s):  
Bo Wang ◽  
Fangyuan Xia ◽  
Michael S. Engel ◽  
Vincent Perrichot ◽  
Gongle Shi ◽  
...  
Keyword(s):  
Fossil Record ◽  
Morphological Characteristics ◽  
Early Evolution ◽  
Behavioral Repertoire ◽  
Wood Fibers ◽  
Morphological Adaptations ◽  
Evolutionary Success ◽  
High Degree ◽  
Insect Assemblage ◽  
Insight Into

Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.

Shear resistance of self-consolidating concrete beams — experimental investigations

2005 ◽  
Vol 32 (6) ◽  
pp. 1103-1113 ◽  
Author(s):  
M Lachemi ◽  
K M.A Hossain ◽  
V Lambros
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Maximum Size ◽  
Shear Resistance ◽  
Resistance Mechanisms ◽  
Experimental Investigations ◽  
Self Consolidating Concrete ◽  
Aggregate Interlock

Self-consolidating concrete (SCC) is a new generation of high performance concrete known for its excellent deformability and high resistance to segregation and bleeding. Lack of information regarding in situ properties and structural performance of SCC is one of the main barriers to its acceptance in the construction industry. There is some concern among researchers and designers that SCC may not be strong enough in shear because of some uncertainties in mechanisms resisting shear — notably the aggregate interlock mechanism. Because of the presence of comparatively smaller amount of coarse aggregates in SCC, the fracture planes are relatively smooth as compared with normal concrete (NC) that may reduce the shear resistance of concrete by reducing the aggregate interlock between the fracture surfaces. The paper compares the shear resistance of SCC and NC based on the results of an experimental investigation on 18 flexurally reinforced beams without shear reinforcements. The test parameters include concrete type, maximum size of coarse aggregate, coarse aggregate content, and beam shear span-to-depth ratio. Shear strength, shear ductility, crack patterns, and failure modes of all experimental beams are compared to analyze the shear resistance mechanisms of SCC and NC beams in both pre- and post-cracking stages. The recommendations of this paper can be of special interest to designers considering the use of SCC in structural applications.Key words: self-consolidating concrete, shear resistance, shear resistance factor, aggregate interlock, dowel action.

Experimental Study on the Workability of Self-Compacting Granite and Unwashed Gravel Concrete

2017 ◽  
Vol 31 ◽  
pp. 69-76
Author(s):  
Gideon O. Bamigboye ◽  
David O. Olukanni ◽  
Adeola A. Adedeji ◽  
Kayode J. Jolayemi
Keyword(s):  
Experimental Study ◽  
Coarse Aggregate ◽  
Mix Design ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Consistency Test ◽  
Coarse Aggregates ◽  
Slump Flow ◽  
Filling Ability ◽  
Passing Ability

This study deals mainly with the mix proportions using granite and unwashed gravel as coarse aggregate for self-compacting concrete (SCC) and its workability, by considering the water absorption of unwashed gravel aggregate. Mix proportions for SCC were designed with constant cement and fine aggregate while coarse aggregates content of granite-unwashed gravel combination were varied in the proportion 100%, 90%/10%, 80%/20%, 70%/30%, 60%/40%, 50% /50%, represented by SCC1, SCC2, SCC3, SCC4, SCC5 and SCC6. 100% granite (SCC1) serves as the control. The workability of the samples was quantitatively evaluated by slump flow, T500, L-box, V- funnel and sieve segregation tests. Based on the experimental results, a detailed analysis was conducted. It was found that granite and unwashed gravel with SCC1, SCC2 and SCC3 according to EFNARC (2002) standard have good deformability, fluidity and filling ability, which all passed consistency test. SCC1, SCC2 and SCC3 have good passing ability while all mixes were in the limit prescribed by EFNARC (2002). It can be concluded that the mix design for varying granite-unwashed gravel combination for SCC presented in this study satisfy various requirements for workability hence, this can be adopted for practical concrete structures.

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