Test Cubes Research Articles

Effect of Time Constraint in Exploring Spatial Differences With Balanced Allocation of Performance Factors in a Redrawn Mental Rotation Test

To achieve a comprehensive and unbiased measurement, a mental rotation test (MRT) (cube form) was redrawn and administered with influential performance factors, namely, time constraint, item type, angular disparity, and rotation/flipping. Item type, angular disparity, and rotation/flipping were systematically balanced into the items of the redrawn Pentomino-MRT, and two time-constraint conditions were randomly assigned to 813 Grade 4 to 6 primary students when administering the test. Children of these ages are of investigative interest because they are at crucial stages of spatial ability development and are at an age where associated gender differences emerge. The study demonstrates that spatial gender differences can be detected in Grade 4, are more marked in Grade 5, and become stable in Grade 6. The importance of time constraint is acknowledged in how and at what grade gender differences emerge under the conditions of the performance factors investigated. In particular, the performance of girls reminds us to focus on their spatial ability development if later STEM-related field participation is of concern.

Shear Strength of Reinforced Fibrous-self Compacted Concrete Box Girder using Recycled Concrete Aggregate

Protection of environmental and conservation of natural resources is a fundamental issue in today’s world. In this research, the shear behavior of reinforced concrete box girders with recycled aggregate (RA), steel fiber, and internal diaphragms were investigated. Eleven reinforced concrete box girders with typical longitudinal and transverse reinforcement were tested under two point loading until failure. The RA was prepared by crushing the collected waste of concrete from the laboratory test cylinders and cubes. The experimental variables considered include; RA percent of 50%, 75%, and 100%(replacing from NA), steel fiber with volumetric ratios (Vf) of 0.5%, 1.0%, and 2%, diaphragm numbers (two and three).The test results revealed that the shear strength of the box girders affected by the RA content, the ultimate load was decreased by (32, 25, and 19) % for the (100, 75, and 50) %RA concrete, respectively in compared with the control specimen. In contrast the steel fiber was more effective in strengthening of the RA concrete specimen, for the (Vf) of 0.5%, 1.0%, and 2.0% with non-fibrous 100% RA concrete, the strengthening were (25, 40, and 77) % respectively. Moreover, when 1.0% steel fibers added to the 100%, 75%, and 50%RA concrete respectively, the strengthening were (40 ,45 ,and48 )% compared each with its reference specimen. On the other hand, when two and three diaphragms used, the strengthening for the non-fibrous 100% RA concrete was (6% and 9%) respectively. cracking load, ultimate load, load- deflection, and concrete surface strain has been taken into consideration in this research.

Hygrothermal investigation of lightweight steel-framed wall assemblies in hot-humid climates: Measurement and simulation validation

In recent years, lightweight steel-framed (LSF) constructions are considered sustainable and widely used worldwide. However, the LSF wall assemblies have the risk of durability failure in hot-humid climates. This study conducted fundamental research on the hygrothermal performance of LSF wall assemblies by characterizing the hygrothermal responses, modelling and validating the simulation models under hot-humid climatic conditions. Through measuring the relative humidity and temperature of various positions inside, four typical and full-scale LSF wall assemblies were tested thoroughly and comparatively on two room-like test cubes in Guangzhou, a hot-humid city in China. It was found that the ventilated rainscreen provided better hygrothermal responses of the wall assemblies than the face-sealed cladding; the closed-cell external insulation could significantly improve the hygrothermal responses of the wall assemblies with stucco cladding; generally, wall assemblies with ventilated rainscreen and external insulation exhibited the best hygrothermal response in a hot-humid climate, followed by wall assemblies with ventilated rainscreen, wall assemblies with face-sealed cladding and external insulation and wall assemblies with face-sealed cladding. Furthermore, the measured data were used to model and validate the simulation models of the four typical wall assemblies in software. It was shown that hygrothermal simulation is sufficient for evaluating the long-term hygrothermal performance of LSF wall assemblies in hot-humid climates, and relatively conservative settings are necessary for evaluating cases with great uncertainties. Overall, this study could lay a foundation for better assessing and improving the hygrothermal performance, durability and sustainability of LSF buildings in hot-humid climate regions worldwide.

Influence of Selected Curing Techniques on Compressive Strength of Concrete From Palm Kernel Shell Ash and Ordinary Portland Cement

This paper discusses the findings of an experimental study on the effect of various curing procedures on the compressive strength of concrete produced by partially substituting portland cement with Palm Kernel Shell Ash (PKSA). Palm kernel shell ash was utilized in a 1:2:4 mix ratio as a partial substitute for ordinary Portland cement (OPC) at percentage levels of 0%, 10%, and 15%. River sand with particles passing a 4.75 mm BS sieve was used, as well as crushed aggregate with a maximum size of 20 mm, and palm kernel shell ash with particles passing a 212 μm sieve. The compressive strength of the test cubes (150 mm x 150 mm x 150 mm) was determined after 7, 28, and 56 days of curing. The results demonstrated that test cubes containing Palm kernel shell ash developed strength over a longer curing period than ordinary Portland cement concrete samples and that the strength changes depending on the amount of PKSA in the cube samples. The findings showed that at 28 days, test cubes with 5%, 10%, and 15% PKSA content in all curing procedures utilized obtained a greater compressive strength. Curing by immersion produced the highest compressive strength in all replacement level while the concrete cured by sprinkling and spraying gives a lower strength in all replacement leve

Functional Constraints in the Selection of Two-Cycle Gate-Exhaustive Faults for Test Generation

Two-cycle gate-exhaustive faults provide a comprehensive model for delay defects that are localized to gates (cells or subcircuits). However, the number of two-cycle gate-exhaustive faults can be excessive. Cell-aware faults are obtained by performing layout analysis of cells to select faults that are important to detect. This article suggests a complementary view of faults that are important to detect. Under this view, a two-cycle gate-exhaustive fault is important to detect if it can affect the circuit during functional operation. Such faults can be identified by generating functional broadside tests. To obtain unconstrained two-cycle tests, which are more compact and detect more faults than functional broadside tests, the article uses a test generation procedure that extracts test cubes from functional broadside tests, merges the test cubes into tests, and derives both broadside and skewed-load tests from the resulting test data. The procedure is iterative to allow a gradual increase in the number of tests and the number of detected two-cycle gate-exhaustive faults. Experimental results for benchmark circuits demonstrate the tradeoff explored by the procedure.

Synchronized Multi-Rate Test Pattern Generation Using Hybrid Twisted Ring Counter and LFSR for BIST Application

This work presents a new approach for built-in test pattern generation (BIST) based on the variable rate clock-driven linear feedback shift register (LFSR) and twisted-ring counters (TRCs). The proposed technique operates on different operating clocks for generating deterministic test pattern sequence for the circuit under test (CUT). The test vectors generated by LFSR are transformed and reproduced with TRC results. The TRC design constitutes of only flip-flops, which be used as a potential alternative to improved seed storage and complex multi polynomial configurations in LFSR.Moreover, the control logic is simplified with synchronized multi-rate clock generation and can be easily extended for any test cubes among multiple CUTs. The randomness characteristics of LFSR are retained with improved memory efficiency and considerable complexity reduction. Experimental results validate the proposed test pattern generator (TPG) over existing well-known LFSRs models, and its randomness is proved with ISCAS benchmark circuits.

Mechanical properties on light weight aggregate concrete using high density polyethylene granules

This present research and explores the properties of concrete's structural and durability High-density polyethylene granules (HDPE) are partly replaced by the coarse aggregate. Five separate concrete mixtures of grade M30 have been built to partially replace the coarse aggregate from 1% to 5%. The properties of strength and durability such as compressive strength, split tensile test, flexural test and durability test such as rapid chloride permeability test, acid test, alkaline test, sulphate test assault. In the acids, the samples will equate with control concrete after 190 days for durability test cubes. The experiment is conducted to evaluate how much the acid attacks on the concrete. The loads are determined by an average of 3 for the compressive strength, split tensile, flexural test.

Effect of recycled course aggregate from concrete debris on the strength of concrete

The paper investigates the fresh and hardened mechanical properties of a concrete mix produced with partial or full substitution of natural aggregates with recycled aggregates from demolition works and crushed tested cubes concrete from laboratory. Recycled aggregate concrete (RAC) is the concrete that has been made from waste materials recycled as coarse and/or fine aggregate. One of the waste materials is the concrete that is taken from demolished buildings in Iraq due to military operations on 2014 and the other is crushed tested concrete cubes from laboratory. Choosing crushed concrete wastes from demolition works and crushed test cubes concrete from laboratory as source of recycling would result in reusing portion of the waste products of the concrete production industry. This study presents an experimental study on the performance of concrete that contains recycled coarse aggregate. The replacement percentages of natural coarse aggregate with the recycled coarse aggregate are (0, 33.3, 66.7 and 100) %. Moreover, silica fume was used as an admixture for all recycled aggregate concretes. Compressive and indirect tensile strength were studied for all of the reference and recycled aggregate concretes at (28) days age, by testing concrete cubes and cylinders specimens respectively. The results showed that the compressive strength and splitting tensile strength decreased for recycled waste concretes taken from demolished buildings and increased for recycled crushed tested cubes concretes from laboratory as compared to the reference concrete. When the silica fume was added, the compressive strength and tensile strength increased for all recycled aggregate concretes compared to those without the silica fume.

Study of Industrial Grade Thermal Insulation at Elevated Temperatures.

Thermal insulation is used for preventing heat losses or heat gains in various applications. In industries that process combustible products, inorganic-materials-based thermal insulation may, if proven sufficiently heat resistant, also provide heat protection in fire incidents. The present study investigated the performance and breakdown temperature of industrial thermal insulation exposed to temperatures up to 1200 °C, i.e., temperatures associated with severe hydrocarbon fires. The thermal insulation properties were investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and by heating 50 mm cubes in a muffle furnace to temperatures in the range of 600 to 1200 °C with a 30 min holding time. The room temperature thermal conductivity was also recorded after each heat treatment. Upon heating, the mineral-based oil dust binder was released at temperatures in the range of 300 to 500 °C, while the Bakelite binder was released at temperatures in the range of 850 to 960 °C. The 50 mm test cubes experienced increasing levels of sintering in the temperature range of 700 to 1100 °C. At temperatures above 1100 °C, the thermal insulation started degrading significantly. Due to being heat-treated to 1200 °C, the test specimen morphology was similar to a slightly porous rock and the original density of 140 kg/m3 increased to 1700 kg/m3. Similarly, the room temperature thermal conductivity increased from 0.041 to 0.22 W/m∙K. The DSC analysis confirmed an endothermic peak at about 1200 °C, indicating melting, which explained the increase in density and thermal conductivity. Recently, 350 kW/m2 has been set as a test target heat flux, i.e., corresponding to an adiabatic temperature of 1200 °C. If a thin layer of thermally robust insulation is placed at the heat-exposed side, the studied thermal insulation may provide significant passive fire protection, even when exposed to heat fluxes up to 350 kW/m2. It is suggested that this is further analysed in future studies.

Hands-On Exploration of Cubes' Floating and Sinking Benefits Children's Subsequent Buoyancy Predictions.

Children accrue experiences with buoyancy on a daily basis, yet research paints a mixed picture of children’s buoyancy knowledge. Whereas children’s predictions and explanations of the floating and the sinking of common objects are often based on a single feature (e.g., mass or facts), children’s predictions of novel cubes reveal solution strategies based on mass and volume integrations. Correspondingly, category learning theory suggests that categories (e.g., floaters vs. sinkers) are easier to identify when items mainly vary from one another in the relevant defining features. For example, a set of cubes only varies in mass and volume and hence density, thereby being able to highlight the deterministic role of density when placed in water. Here we asked how item variation during hands-on exploration affects children’s subsequent predictions and explanations of buoyancy. Kindergarteners and first-, second-, and third-grade children individually explored either a set of 10 systematically varied cubes (i.e., systematic condition; n = 95) or a set of 10 common objects (i.e., non-systematic condition; n = 96) in a water basin. Next, the children predicted the buoyancy of five new cubes and five new common objects one at a time. Subsequently, the children explained their predictions one subset at a time. The children in the systematic condition were more accurate in their predictions of the test cubes than the children in the non-systematic condition. Latent class regression analyses identified three cube prediction solution strategies. The children in the systematic condition were more likely to use a strategy in which buoyancy decisions were made based on an accurate integration of mass and volume, while the children in the non-systematic condition were more likely to use a strategy in which mass was given more predictive load than volume. A third strategy was characterized by guessing. Latent class analyses of the children’s explanations revealed different explanation strategies, each appealing to several features, but as hypothesized, no clear condition differences were found. The findings indicate that even 5 min of exploration with systematically varied cubes can already help children use an advanced buoyancy prediction strategy. This provides evidence in favor of using category learning theory to inform early science education design.

Sintering of ceramics for clay in situ resource utilization on Mars

The sintering of wet processed Mars global simulant green bodies is explored. Green bodies shaped using slip casting, throwing on a potter’s wheel and additive manufacturing, including material extrusion (robocasting) and layerwise slurry deposition (LSD) are sintered in terrestrial and simulated Mars atmosphere. A sintering schedule is developed using hot stage microscopy, water absorption, sintering shrinkage and sintering mass loss. Sintered parts are characterized in respect to their density, porosity, phase composition, microstructure and mechanical properties. Densification behavior for different green bodies was generally similar, enabling the fabrication of larger green bodies (tiles, cups, bowls) and parts with fines details (test cubes and cuneiform tables) with low water absorption. Sintered LSD discs had a bending strength between terracotta and typical porcelains with 57.5/53.3 ​MPa in terrestrial/simulated Mars atmosphere. Clay ISRU for sintered ceramics can be considered an eminently favorable construction technology for soft and hard ISRU on Mars.

Hybrid encoding for test data compression

Main disputes of digital integrated circuits testing are increasing test data volume and test power. The proposed encoding schemes are a combination of nine coded and selective pattern compression, Alternate Variable Run length code to reduce test data volume. The test cubes are divided into multiples of 8, 16, 32, and 64 blocks to upsurge the relationship among the successive test patterns which offers enriched test data reduction. The test data blocks are encoded with two methods in order to reduce test data volume. In the first method, the test sets are encoded using nine coded with selective pattern coding to expand the test data density. In the second method, the test sets are encoded using nine coded with Alternate variable run length laterally with selective pattern coding to improve the test data compression. Investigational results show that the proposed first and second approaches offer a maximum of 76% and 83% of compression ratio respectively for ISCAS’89 benchmark circuits.

Design of concrete canoe reinforced with composite reinforcement

To participate in international competitions on concrete canoe among students at the Department of concrete and masonry structures KNUBA has been designed and manufactured concrete canoe reinforced composite reinforcement. The design of the canoe was modeled and calculated in the PC «LIRA-SAPR».The problem of this article is to determine the optimal thickness of the walls of the canoe, the composition of basalt fiber and the scheme of reinforcement of the canoe to ensure its strength and crack resistance, as well as sufficient buoyancy. To achieve the minimum weight of the canoe it is customary to use non-metal reinforcement.The dimensions of the wooden canoe were accepted for the concrete canoe project. In terms of canoeing has a lenticular shape. The total canoe length is 4,3 m and maximum width is 900 mm. The minimum height of the board is 400 mm. According to the accepted manufacturing technology, the walls and canoe bottom have a three-layer construction, consisting of an inner and outer layer of basalt fiber concrete 3… 5 mm thick and an inner layer of expanded polystyrene foam 10 mm thick. To strengthen the most intense zones in the outer layer of basalt fiber reinforced carbon mesh. In the transverse direction, transverse ribs (frames) made of expanded polystyrene 20 mm thick and 20… 30 mm high are arranged. Along the upper sides of the sides, along the keel rib and along the frames, basalt reinforcement with a diameter of 6 mm (2 rods) was installed.To calculate the canoe, its calculation model was developed in the LIRA-CAD PC. The canoe model is made in the form of a shell made of flat triangular finite elements. Linear elements were also added to model the basalt reinforcement. Linear and flat elements are rigidly connected at the nodes.According to the manufacturer, the modulus of elasticity of the rod reinforcement is 70∙103 MPa, and the temporary tear resistance - 1100 MPa, density -1,9 g/m3. The basalt fiber was adopted with a thickness of 20 mkm and a length of 50 mm.Two-component waterproofing solution SILTEK V-33/E-33 was used as the concrete matrix. The amount of basalt fiber was 3%. To determine the characteristics of basalt fiber concrete test cubes with an edge of 75 mm and samples-"eight" were made. As a result of the test, the tensile strength of basalt fiber was compressed at 8.4 MPa and the axial tensile strength was 1.8 MPa.The obtained design characteristics were used to introduce finite element stiffnesses.Canoe loading was applied on its own weight, the weight of two 80 kg paddles and hydrostatic water pressure.As a result of the calculation, mosaics of stresses were obtained. They showed the most intense zones, which were reinforced with carbon mesh.After experimental and numerical studies, we came to the conclusion that non-metallic composite reinforcement can be used in the construction of light structural elements. Such structures are absolutely not susceptible to corrosion. In the future, it is necessary to investigate structural elements that are used in the aquatic environment, such as pontoons, platforms for waterfront homes and more.

Features of change in strength and modulus of elasticity of various layers of vibrocentrifuged fiber-reinforced concrete columns of annular section

Upon carrying out the studies, the authors identified the features of strength and elastic modulus variation of different layers of vibration centrifuged fiber-concrete tubular columns. They provide rationalization for the variational nature of test structures, i.e. combinations of layers, the properties and characteristics of which are different. To reveal the trends of changes in the physical and mechanical properties of a structure by layers, the authors performed a through ultrasonic scanning using a Pulsar 2.2 device. The authors verified the applicability of the described technique for the variational vibration centrifuged structures. Three test cubes used for compression strength determination were produced from each the inner, middle, and outer layers. Confirming theoretical data on centrifugal molding, the authors revealed that the outer layer of the structure, which experienced the maximum centrifugal force, had the greatest strength, and the inner layer had the minimal strength. Substantiation of the fact that the variational vibration centrifuged structure is three-layered was confirmed experimentally.

A variable-length compatible compression scheme based on tristate signals

The test data volume for the manufacturing test of chips is increasing rapidly. This is due to the fact that the complexity of these chips is increasing rapidly and the transistor count is increasing exponentially. Aimed at solving the problems of large test data volume and long test time in chips test, this paper presents a deterministic test-based compression method that uses tristate signals encoding and compatible test cube merging. Firstly, the partial input reduction is carried out for the original test set. The proportion of “don’t care” bits in the original test set is increased by merging compatible or inversely compatible inputs in the test cubes, so the compatibility among the test cubes is improved. Then, the test set is compressed and encoded by using tristate signal. Each test cube is divided into several data segments, which are encoded by tristate signals and multiple compatibility rules. This scheme can improve the compression ratio of the test set. The experimental results show that the proposed scheme achieves a good compression ratio, without excessive test power and area overhead. The average test compression ratio can reach 82.15%.

Strength and Durability Research on Concrete with Partial Replacement of Cement by Rice Husk Ash and Spent Bleaching Earth

Concrete is the foremost building material in the region of the sphere and used in operational works, including infrastructure, low and high-rise buildings. Substitution of waste materials will conserve dwindling resources, and will avoid the environmental and ecological damages caused by quarrying and exploitation of the raw materials for making cement. So we are interested in replacement of cement with waste materials coming from oil industry and rice mill industry. So we are taking spent bleach earth (SBE) from oil industry & rice husk ash (RHA) from rice milling industry. W/c ratio as 0.38 and SP 430 IS used for obtaining required slump. The required slump is arrived at 0.7% of admixture. Following replacing the Cement with SBE 5%, 7.5%, 10% and RHA with 2%, 4%, 6%, 8%, 10% aimed at optimum results. Now SBE5% & RHA 8% got optimum values. Subsequently beams, cylinders, cubes are casted. Compressive strength, Split tensile strength, Flexural strength originate for 7 days & 28 days. Later 28 days curing cubes are placed in Hydrochloric acid (HCL) for durability test. For durability test cubes are submerged in 5% of HCL for additional 28days & find the Compression strength.

Low Cost Hypercompression of Test Data

This article presents a next-generation test data compression scheme. It builds on the isometric compression paradigm, but makes it more flexible and elevates encoding efficiency to values unachievable through state-of-the-art sequential compression schemes. Furthermore, its programmable selection of full-toggle scan chains ensures high test coverage and virtually eliminates compression aborts. The presented approach follows from a fundamental observation that among test cube care bits, only a very few have a status of necessary assignments (their locations cannot be changed), whereas the remaining ones have alternative sites. These test cubes are used to form circular test templates which synergistically control a decompressor and guide back ATPG to find assignments yielding highly compressible test patterns. A redesigned low-silicon-area decompressor is also capable of reducing switching rates in scan chains with a new test power control scheme. The experimental results obtained for large industrial designs and other benchmark circuits confirm the superiority of the proposed scheme over existing techniques and are reported herein.

Utilization of M-Sand & Basalt Fiber in Concrete: An Experimental Study on Strength and Durability Properties

The main aim of this project is to found a suitable alternative for the natural river sand, which is reaching maximum level of scarcity. M-sand is used along with the addition of natural basalt fibres in to the concrete. Mix design arrived for M25 using IS 10265 codal provisions. Initial properties test for fine aggregate (M-sand), coarse aggregate and cement were obtained in the laboratory. Basalt fibres are added in terms of volume fraction of 0%, 0.25%, 0.50% and 0.75% in to the concrete. Experimental investigations on fresh concrete were studied by conducting slump test, compaction factor test and Vee bee test. Also conducted experimental studies on strength and durability characteristics of basalt fibre reinforced concrete. For investigating strength test cubes and cylinders were casted for arriving compressive strength and split tensile strength. For durability studies, porosity tests (Water absorption test) were conducted. In the test, it is observed that, 0.75% volume fraction of basalt fibre reinforced concrete found optimum in terms of achieving strength and durability aspects. In our experimental studies, it found that M-sand can be effective alternative for the natural river sand.

LFSR‐based generation of boundary‐functional broadside tests

This study considers the compression of a type of close-to-functional broadside tests called boundary-functional broadside tests when the on-chip decompression logic consists of a linear-feedback shift register (LFSR). Boundary-functional broadside tests maintain functional operation conditions on a set of lines (called a boundary) in a circuit. This limits the deviations from functional operation conditions by ensuring that they do not propagate across the boundary. Functional vectors for the boundary are obtained from functional broadside tests. Seeds for the LFSR are generated directly from functional boundary vectors without generating tests or test cubes. Considering the tests that the LFSR produces, the seed generation procedure attempts to obtain the lowest possible Hamming distance between their boundary vectors and functional boundary vectors. It considers multiple LFSRs with increasing lengths to achieve test data compression. The procedure is structured to explore the trade-off between the level of test data compression and the Hamming distances or the proximity to functional operation conditions.

Study on the Concrete in Chloride Environment Based on Electrochemical Impedance Spectroscopy

In this paper, the effect of water-cement ratio and chloride ions on the concrete meso-structure was studied. Three kinds of concrete cubes with different water-cement ratios were immersed in fresh water and salt water, respectively. Then, the Electrochemical Impedance Spectroscopy (EIS) analysis of various test cubes were carried out by using electrochemical workstation. The results show that the salt water can improve electric double layer capacitance in the test cubes with the same water-cement ratio, but it can reduce some other parameters such as resistance of pore solution, resistance to transfer the hydrated electron, coefficient of diffusion impedance of concreter, which shows that the chloride ions diffused into the concrete in salt water and increase the ionic concentration in pore solution and C-S-H gel. However, the phase angle index is constant whether in fresh water or salt water, which shows chloride ions cannot affect the concrete meso-structure even though they can improve the ion concentration of pore structure. For the concrete test cubes which has different water-cement ratio in salt water, with the reduction of water-cement ratio, the electric double-layer capacitance of concrete remains unchanged, which indicates when the water-cement ratio becomes smaller, the porosity becomes lower, and the internal structure of concrete becomes denser.