Concrete Categories Research Articles

A Systematic Investigation into the Generation of Words Using Semantic Priming Experiments

Semantic priming facilitates word generation by improving the ability to produce semantically related words. However, age-related neurobiological changes may diminish this capacity. This study investigates the effect of aging on word generation across different semantic categories in 150 healthy individuals, aged 31 to 80, divided into five age groups. Participants were tasked with generating words in the categories of synonym, antonym, abstract, and concrete, using the DMDX software. The number of words generated and the accuracy of responses were recorded. The findings revealed statistically significant differences (p < 0.05) in the number of words generated across most age groups, with the exception of adjacent age groups (31–40 vs. 41–50, 41–50 vs. 51–60, and 61–70 vs. 71–80), where no significant differences were observed. These results suggest that neurobiological changes between adjacent age groups are subtle. The reduced performance observed in older adults may be attributed to a diminished ability to strategically access and retrieve lexical forms from semantic memory. However, semantic priming appears to mitigate these age-related declines, preventing significant differences between adjacent age groups.

Mechanical properties of high-volume fly ash concrete with varying fly ash content

Fly ash is widely used as a replacement for cement to produce more environmentally friendly concrete with reliable performance in construction applications. Therefore, this research aimed to analyze the mechanical properties of high-volume fly ash concrete (HVFAC) using class F fly ash with different percentages. Performance tests that were carried out included workability, unit weight, and compressive strength. Laboratory experiments were conducted by making 5 variations of mix design, namely variation 1 (FA0), which consisted of normal concrete with a control test material of 100% Portland cement. The other 4 variations were HVFAC (FA70, FA80, FA90, and FA100), which were made with fly ash content comprising 70%, 80%, 90%, and 100% of the total binders/cementitious. Fresh concrete was tested for workability, while hardened concrete was tested for unit weight and compressive strength at ages 3, 7, and 28 days on test specimens subjected to water immersion curing. The results showed that all workability of HVFAC test specimens met the self-consolidated concrete (SCC) category. The dry unit weight of all specimens met the requirements for normal-weight concrete. The results of the compressive strength test at 28 days showed that the addition of fly ash percentage caused a decrease in the compressive strength value of the entire HVFAC, but still exceeded the minimum requirements for high-quality concrete. HVFAC with variations FA70, FA80, and FA90 met the requirements of ASTM C618-12a based on the evaluation of Strength Activity Index (SAI) values at 7 and 28 days of age, while FA100 did not meet the requirements.

Mechanical properties and radiological implications of replacing sand with waste ceramic aggregate in ordinary concrete

The mining of aggregates for the production of concrete creates ecological problems. In this study, the effect of partially replacing sand as fine aggregate (FA) with waste ceramic tiles (WCT) on the density, compressive strength (CS), specific radioactivity of naturally occurring radioactive materials (238U, 232Th, and 40K), and the radiation shielding competence of concrete was investigated. Ordinary concrete samples consisting of cement, fine aggregate (river sand), coarse aggregate (granite), and water were prepared in 50 mm × 50 mm x 50 mm cubical steel moulds. The samples were coded as C-WCT0, C-WCT5, C-WCT10, C-WCT15, C-WCT20, and C-WCT25, representing concrete samples in which the FA component was replaced by 0, 5, 10, 15, 20, and 25% pulverized WCT, respectively. The CS and density of the samples were determined after 7-, 14-, and 28-day curing periods. The gamma spectrometric method was used to determine the specific activity of 238U, 232Th, and 40K using a hyper pure germanium detector. The photon and neutron shielding parameters of the concrete blocks were calculated with the aid of the EPICS2017 cross-section library and relevant standard formulae. The mean CS for each concrete category increase with curing age. The density of the concrete varied from 2213 kg/m3 to 2488 kg/m3 as the FA replacement level rose to 15%. Using WCT as a partial replacement for FA altered the chemical composition and decreased the specific activities of 238U, 232Th, and 40K, in the concrete samples. C-WCT15 had the best gamma photon and fast neutron absorption features among the concrete samples. The use of WCT as aggregate in concrete production is a sustainable and environmental-friendly way of producing concrete for general civil engineering and shielding applications in medical and other radiation facilities. This study also affirms that using alternative materials with lower specific activity to replace sand is radiologically desirable in reducing the indoor radiation dose of occupants of concrete-based structures. The replacement of 15% sand by WCT produced stronger, radiologically safer, and more effective radiation absorbing concrete.

Feasibility of foam concrete using recycled brick and roof tile fine aggregates

Brick (BR) and roof tile (RT) fine aggregate fractions derived from construction and demolition wastes have a low recycling rate in new construction and building materials. This article assesses their suitability for replacing the limestone aggregate in foam concrete, which helps valorise such fractions and conserve natural limestone resources. Two concrete categories containing or not silica fume (SF) were investigated, while the BR and RT aggregate replacement rates were 10%, 20% and 40%. Tested properties include flow, density, water absorption, porosity, thermal conductivity, mechanical strengths, microscopy, drying shrinkage, resistance to freeze/thaw cycles and elevated temperature. Results showed that the concrete mechanical properties improved when the limestone aggregate was replaced by 10% BR or RT but gradually curtailed at higher addition rates. Such results concorded with the density, water absorption and porosity measurements. Foamed concrete containing BR is more resistant (compared to RT) to drying shrinkage, freeze/thaw cycle, and heat exposure, which was ascribed to the relatively lower BR porosity that improves the concrete mechanical properties and durability.

Characteristics of concrete incorporating construction and demolition waste aggregate and post-consumer tires rubber and steel fibers

This study aims at investigating the performance of Portland cement concrete incorporating construction and demolition waste aggregate in conjunction with rubber and steel fibers from post-consumer tires. Eight concrete mixes were prepared and tested. In these, natural coarse aggregate (NCA) was replaced by 100 % recycled concrete aggregate (RCA) and/or 20 % and 40 % rubber coarse aggregate (RuCA). The contribution of post-consumer tire steel fibers (PCTSF) to the behavior of the various recycled concrete mixes was also examined. The axial compressive stress–strain, flexural stress–deflection, and splitting tensile strength behaviors together with the dry density, porosity and rapid chloride penetration for all concrete mixes were investigated and compared. The results indicated that increasing the replacement levels of RuCA resulted in a decrease in concrete strength, although the decrease was less pronounced in the concrete mixes with RCA than in mixes incorporating NCA. Specifically, the reductions in compressive, tensile and flexural strengths were respectively as much as 6.6 %, 12.9 % and 14 % less in the mixes containing RCA. Also, the addition of PCTSF substantially mitigated the reductions in strength and, more significantly, the deflection at peak stress was increased by up to 664 %. Furthermore, incorporation of these fibers maintained up to 47 % of the flexural peak strength of the concrete mix at 4 mm deflection in the post-peak region. Additionally, the porosity of the concrete mixes ranged from 6 % to 12 %, placing them in the high-durability concrete category. The dry density exhibited an inverse relationship with the rubber aggregate content, resulting in a reduction of up to 10.2 % compared to the control mix. Hence, utilizing a substantial volume of post-consumer tire materials in recycled-aggregate concrete mixes is envisaged as an ideal choice in construction applications where lower concrete rigidity is desired, for example in seismic or vibrated zones. The approach also aligns with the increasing emphasis on sustainable construction materials.

Experimental and numerical research on shear performance of GFRP bar reinforced seawater sea-sand concrete deep beams without stirrups

Using glass fibre-reinforced polymer (GFRP) bars to reinforce seawater sea-sand concrete (SWSSC) is a feasible way to replace traditional concrete structures. Thus, this paper aims to understand the shear response of GFRP bar-reinforced SWSSC (GFRP-SWSSC) deep beams. Experimental and numerical programs were carried out on four-point shear tests of GFRP-SWSSC deep beams without stirrups. Seventy specimens were tested to investigate the effects of key parameters on shear responses, including concrete categories, seashell content, section heights, and GFRP bar diameter. The test results indicated that the cracking strength of GFRP-SWSSC deep beams was slightly higher than ordinary concrete deep beams. The increased section height of GFRP-SWSSC deep beams and the decreased shell content remarkably enhanced the stiffness and shear ultimate strength. The corresponding finite element model (FEM) of GFRP-SWSSC specimens was established and validated by comparison with test results. Further, three guidelines predictions for the shear strength of GFRP-SWSSC beams were too conservative. The new design formulae derived from modified tension-compression theory were put forward to evaluate the shear strength of GFRP-SWSSC deep beams, and the comparisons demonstrated that the proposed design formulae achieved sufficient accurate predictions for practical engineering. Based on research on shear performance, the hybrid GFRP-SWSSC structure is a feasible solution to resource shortages, which provides a promising application prospect in marine engineering.

UTILIZATION OF HIGH-VOLUME FLY ASH AS A SUPPLEMENTARY CEMENTITIOUS MATERIAL IN ENVIRONMENTALLY FRIENDLY CONCRETE

Innovations in material technology are expected to reduce the use of commercial cement and replace it with other environmentally friendly materials with the same performance as normal concrete. Aim: This study aim to analyze the mechanical property of High-Volume Fly Ash Concrete (HVFAC) using F class fly ash with different mix percentages. Methodology and Results: The experiment was conducted in laboratory scale. Four variations of test specimens consisted of: 1 variation (F0), which is conventional concrete with 100% Portland cement as control specimen, and three variations of HVFC (F70, F80, and F90), which were made with fly ash content (%) 70, 80, and 90 of total cementitious. Fresh concrete testing to determine workability, while hard concrete testing is done by density and compressive strength tests at the age of 3, 7, and 28 days on specimens that have been treated with the water submerged curing method. Conclusion, significance, and impact of study: All HVFAC specimens fulfill the Self Compacting Concrete (SCC) category. The compressive strength test results at 28 days showed that the addition of fly ash percentage caused a decrease in compressive strength values in all HVFAC variants, but still exceeded the minimum requirements of high and medium quality concrete. All HVFAC variations meet the requirements of ASTM C618-23 based on the evaluation of Strength Activity Index (SAI) values at 7 and 28 days of age. The utilization of 90% fly ash as a cement substitute resulted in an environmentally friendly concrete product based on the concept of cleaner production.

Mapping the Jews in the Byzantine Hymnography: The Triodion

The Byzantine hymnography was considered a “stumbling stone” of the Jewish–Orthodox Christian dialogue because of the harsh anti-Jewish elements kept in the modern liturgical texts without any revision. This article analyses the often-mentioned texts of the Triodion—the liturgical period before Pascha—using a quantitative approach. The starting point of this research states that we must keep in mind the broader view on the state of the hymnography without labelling the entire Byzantine hymnography as anti-Jewish by looking at some concrete stanzas from Holy Week services. The results demonstrate that we can speak only about very few hymnographical texts containing anti-Jewish elements compared to the entire Triodion. This approach helps us in the Jewish–Christian debates to focus on what exactly are we speaking about, and what precisely those texts are saying. After a short analysis of the content of selected hymns, I propose three concrete categories of hymns that could be more easily approached by either excluding them or transforming them through translation into modern languages.

Effect of Accelerators on High Early Strength Concrete (HESC) Using High Volume Fly Ash

Applying large quantities of fly ash for the production of High Early Strength Concrete (HESC) is a challenge for researchers in the utilization of quality, inexpensive, and environmentally friendly materials. A high volume of fly ash in concrete, however, reduces the initial compressive strength of the concrete. For this reason, it is necessary to use admixture additives in the concrete mixture to get the expected performance. This research seeks to identify the optimal HESC mix design using fly ash 50% of the total cementitious by adding a superplasticizer and accelerator to obtain a high initial compressive strength. Three variations of HESC, namely HESC-12, HESC-14, and HESC-16, were made using a superplasticizer and accelerator with different doses. Each variation uses 12 liters of superplasticizer and different accelerator volumes: 12 liters, 14 liters, and 16 liters. Specimen testing was carried out on fresh and hard concrete. Fresh concrete was subjected to a slump test, whereas hard concrete was subjected to compressive tests at 18 hours, 24 hours, 3 days, and 28 days of age. The average slump flow values for HESC-12, HESC-14, and HESC-16 (cm) were 78, 79.5, and 80, respectively, demonstrating that all HESC samples are classified as self-compacting concrete (SCC). According to the results of density tests conducted on all specimens ranging from 2461 to 2538 kg/m3, all specimens are included in the category of normal-weight concrete. Within the range of 29.8 to 35.3 MPa for the initial compressive strength of HESC at 24 hours of age, it can be concluded that all HESC specimens fulfill the criteria for high early-strength concrete. The addition of the right type and dosage of chemical admixture is a solution to overcome the weakness of applying fly ash in high-early-strength concrete.

Mechanical properties and flexural behaviour of green light weight concrete beams exposure to salty soils

This paper presents an experimental investigation on the mechanical properties, durability and flexural behaviour of green concrete beam when subjected to harsh environments by using recycled building materials. Concrete resistance to external aggressive environmental condition is one of the most significant characteristics to maintain the concrete durability. The fundamental goal of this study is to understanding the performance of green lightweight concrete beam of (10×10×40 cm) under two different severe saline conditions; Ground Water Condition (GWC) and Severe Saline Clay Soil Condition (SSC) that contain chlorides and sulfates at concentrations like to those existing in groundwater and soil of the southern and middle parts of Iraq. In this research, in addition to normal concrete; three basic categories of green lightweight concrete are used: structural, non-structural and moderate strength using recycled of clay bricks and themestone blocks as coarse Light Weight Concrete (LWA) by a replacement ratio of (0, 50 and 100) % volume of natural coarse aggregate. All green Light Weight Aggregate Concrete (LWAC) beams and related specimens for mechanical properties were subjected to GWC, SSC and Laboratory Air Condition (LAC) for till (3, 6 and 9 months) after twenty-eight days of curing by tap water. Compressive strength, splitting tensile strength and density were also studied. The results obtained offered that the GWC and SSC have impacted the performance of all concrete beam types negatively with exposure age. The decadence was more for non-structural green LWAC beam. It is found that the resistance of beams contains bricks aggregate to GWC and SSC was a better than the other types of the green LWAC, the percentage decreases in failure load were 15.47% and 13.31% at 9 months of exposure to GWC and SSC measured relative to concrete beam exposed to LAC, respectively. Under the effect of aggressive conditions till 3 months, the results clarified that the improvement rate in the mechanical properties of the green LWAC were increased with age in comparison with ordinary concrete. The percentage reduction in compressive, splitting tensile strength and density at 9 months were ranged between (8.70-17.05) %, (14.71-36.50) % and (0.11-3.98) %, respectively measured relative to the same specimens in LAC.

Effect of Incorporating Coal Bottom Ash on The Properties of Concrete

Industrial waste without proper control may lead to contamination and cause environmental pollution. Transforming waste such as coal bottom ash (CBA) wastes into a sustainable construction material is so much help in reducing the waste in the surroundings and is also environmentally friendly. In this research, cement was replaced with CBA in the concrete to analyse the effect on concrete performance. Consequently, this project focuses on physical and mechanical properties of concrete before and after using CBA. In the design stage for concrete mixing, the ratio for raw materials selected was 1:1.35:3.2 for cement, sand, and aggregates, respectively (grade 25). Two different major categories of concrete were made and compared. The first category is ordinary concrete with control concrete mix (CM), while the second category is concrete which uses 5%, 10%, 15%, 20%, 25%, and 30% of CBA partial replacement in the volume of cement in the concrete mix. The samples we used in this research were cubes 100 mm x 100 mm x 100 mm prepared for the water absorption, density, and compression test. The workability of concrete containing CBA with fixed water quantity was lower corresponding to that of the control mix. The hardened concrete density was reduced, and the water absorption increased with an increased amount of ground CBA. The results for the compressive test of control samples are 22.940 N/mm at 28 days of curing, and the highest percentage was 10% CBA which is 28.28 MPa. Since the strength of the concrete with CBA is increasing so, modified concretes can be considered to use in construction.

An axiomatic approach to differentiation of polynomial circuits

Reverse derivative categories (RDCs) have recently been shown to be a suitable semantic framework for studying machine learning algorithms. Whereas emphasis has been put on training methodologies, less attention has been devoted to particular model classes: the concrete categories whose morphisms represent machine learning models. In this paper we study presentations by generators and equations of classes of RDCs. In particular, we propose polynomial circuits as a suitable machine learning model class. We give an axiomatisation for these circuits and prove a functional completeness result. Finally, we discuss the use of polynomial circuits over specific semirings to perform machine learning with discrete values.

The influence of low alkaline activator on the compressive strength and workability of geopolymer concrete

This paper presents the results of research on geopolymer concrete using a reasonably low alkaline activator. The key objective concerning this research is to investigate whether a low alkaline activator is still qualified to produce a concrete compressive strength that fulfills the structural requirements. The experimental program is carried out by making geopolymer concrete specimens, where the variables reviewed represented the amount of alkaline activator (4% and 5%), the ratio of alkaline activator to fly ash (AAS/FA) was 0.35, 0.4, 0.5, 0.6. The treatment temperatures of the specimens were room temperature (33°C) and 60°C. The experimental results of the compressive strength test have shown that the compressive strength of low alkaline geopolymer activator concrete still meets the requirements as a structural material (i.e. Indonesian Concrete Code). The weight of the resulting specimen is included in the category of normal weight concrete. The workability of geopolymer concrete with low alkaline activator tends to be better if the ratio AAS/FA also increases, but the compressive strength of concrete tends to decrease.

The existence of UFO implies projectively universal morphisms

Let C \mathcal C be a concrete category. We prove that if C \mathcal {C} admits a universally free object F \mathsf F , then there is a projectively universal morphism u : F → F u\colon \mathsf F\to \mathsf F , i.e., a morphism u u such that for any B ∈ C B\in \mathcal {C} and τ ∈ Mor ⁡ ( B ) \tau \in \operatorname {Mor}(B) there exists an epimorphism π ∈ Mor ⁡ ( F , B ) \pi \in \operatorname {Mor}(\mathsf F, B) such that π τ = u π \pi \tau = u \pi . This builds upon and extends various ideas by Darji and Matheron [Proc. Amer. Math. Soc. 145 (2017), pp. 251–265] who proved such a result for the category of separable Banach spaces with contractive operators as well as certain classes of dynamical systems on compact metric spaces. Specialising from our abstract setting, we conclude that the result applies to various categories of Banach spaces/lattices/algebras, C*-algebras, etc.

Thermal and Acoustic Features of Lightweight Concrete Based on Marble Wastes and Expanded Perlite Aggregate

A large amount of industrial solid waste is generated from industrial activities worldwide. One such waste is marble waste, a waste generated from quarries which is generated in larger amount which needs attention. It is proved that this waste has a significant impact both on the people health and on the environment. Hence, research works are directed towards addressing usage of waste marble power, the aim of this experimental investigation is to study the usability of sand obtained by crushing marble waste (MWS) on the mixing of lightweight concrete based on expanded perlite aggregate (EPA). First, the mechanical, chemical, and physical properties of marble waste sand and expanded perlite aggregate were determined after which different mixtures of concrete are prepared by varying the percentage of EPA (0, 20, 40, 60, 80, and 100%), in order to find the optimum mixture focussing on obtaining best hydraulic properties. Also, in this work, the thermal and acoustic properties (thermal conductivity, thermal diffusivity, specific heat capacity and sound reduction index at different frequencies) of the tested concrete samples were investigated. Results shows that it is possible to obtain thermal and acoustic insulation lightweight concrete by using sand obtained by crushing marble wastes. Also, addition of more than 20% of EPA aggregate in concrete, develops a thermal insulating lightweight concrete which possess capacity to store heat and produce better thermal performance. Concrete blend with a percentage of more than of 20% of EPA aggregate can be placed in the category of acoustic insulation lightweight concrete. In summary, cement based on MWs and EPA provides better workability and energy saving qualities, which are economical and environmentally beneficial and may result in decreased construction budget and improve a long-term raw materials sustainability.

Interor and \(\mathfrak h\) operators of the category of locales

We construct the concrete categories \(\mathbf{I\text{-}Loc}\) and \(\mathbf{\mathfrak h\text{-}Loc}\) over the category \(\mathbf{Loc}\) of locales and we deduce that they are topological categories, where \(\mathbf I\) and \(\mathfrak h\) denote respectively the classes of interior and \(h\) operators of the category \(\mathbf{Loc}\) of locales.

Varieties of ordered algebras as categories

A variety is a category of ordered (finitary) algebras presented by inequations between terms. We characterize categories enriched over the category of posets which are equivalent to a variety. This is quite analogous to Lawvere’s classical characterization of varieties of ordinary algebras. We also study the relationship of varieties to discrete Lawvere theories, and varieties as concrete categories over $$\mathbf{ Pos }$$ .

Prekernels of topologically axiomatized subcategories of concrete categories

In the present work we introduce the notion of proper Moore-concrete subcategory of a given concrete category C over a base category X and show that it agrees with that of reflective modification of C. This allows us to associate with any object C of C an object in B that we call the B-closure of C, and with any morphism in C a unique morphism between the corresponding B-closures that we call the B-closure extension.Next, we provide some general properties of proper Moore-concrete subcategories which will be useful to deeply investigate prekernels, precokernels and pretorsion theories in proper Moore-concrete subcategories with respect to some given class of trivial objects. More in detail, we analyze some different conditions to be put on short sequences of morphisms or on short pre-exact sequences in C in order to get informations on the corresponding B-closure extensions and on the B-closure of the various terms of the associated short sequences of B-closure extensions in B. Furthermore, we induce pretorsion theories on proper Moore-concrete subcategories starting from pretorsion theories on the ambient category C and, more in general, we study the interrelations between pretorsion theories on C and proper Moore-concrete subcategories.Finally, we provide a characterization of trivial morphisms and of prekernels of a functor-structured category when we choose Z to be the class of all projective objects. Next, restricting our attention to set-functor structured categories, we obtain a stable pointed category B/R (and a corresponding subcategory (B/R)⁎ as a quotient of B with respect to a suitable congruence relation R on the hom-sets and use the associated quotient functor to induce a correspondence between prekernels in the subcategory B⁎ without the objects with empty ground set and kernels in (B/R)⁎, and between precokernels in B⁎ and weak cokernels in (B/R)⁎.

Multi-dimensional sensorimotor grounding of concrete and abstract categories.

Semantic categories, and the concepts belonging to them, have commonly been defined by their relative concreteness, that is, their reliance on perception. However, sensorimotor grounding must be regarded as going beyond the basic five senses and incorporate a multi-dimensional variety of perceptual and action experience. We present a series of exploratory analyses examining the sensorimotor grounding of participant-produced member concepts for 117 categories, spanning concrete (e.g. animal and furniture) and highly abstract (e.g. unit of time and science) categories. We found that both concrete and abstract categories are strongly grounded in multi-dimensional sensorimotor experience. Both domains were dominated by vision and, to a lesser extent, head movements, but concrete categories were more grounded in touch and hand-arm action, while abstract categories were more grounded in hearing and interoception. Importantly, this pattern of grounding was not uniform, and subdomains of concrete (e.g. ingestibles, animates, natural categories and artefacts) and abstract (e.g. internal, social and non-social) categories were grounded in different profiles of sensorimotor experience. Overall, these findings suggest that the distinction between abstract and concrete categories is not as clearcut as ontological assumptions might suggest, and that the strength and diversity of sensorimotor grounding in abstract categories must not be underestimated. This article is part of the theme issue 'Concepts in interaction: social engagement and inner experiences'.

A note on a category composition

The special properties of an abstract category morphism (for instance, being an identity, an isomorphism, an epimorphism., a monomorphism . . . ) fully depend on the category composition. Consequently, an isomorphic category to a concrete category may be not concrete, i.e., the concreteness is not a category invariant. Further, every small category is isomorphic to a small category whose objects are sets and whose morphisms are functions between those sets.