Percent Volume Fraction Research Articles

Flexure and shear behaviour of self-compacting reinforced concrete beams with polyethylene terephthalate fibres and strips

One of the major environmental concerns is the disposal of the solid waste. The limited landfill sites intensify the issue and increase the need for alternative use of solid waste. Plastic drinking bottles made of Polyethylene Terephthalate (PET) are one of the major portions of solid waste. Beverage containers are made by PET and are intended for single use only. This study is focused on the use of PET as Fibres cut from waste drinking bottles in concrete. Long strips and Short PET fibres cut it from waste beverage bottles were used in self-compacting reinforced concrete (SCRC) beams as reinforcement. Together with the steel reinforcement in beams, the PET strips or fibres were used with, and without shear reinforcement. In SCRC beams detailed for the flexural and shear failure, the 1 percent volume fraction of short strips or fibres were used. Material properties such as compressive strength, elastic modulus were performed along with the beams tested under four-point bending. The results were analysed and compared with strips or fibres reinforced beams with a control beam. Based on the results, it was found that PET bottles as strips or fibres could be used as shear and flexural reinforcement in concrete as enhance in ductility, load capacity and shift of mode of failure were observed with strips and fibres.

Numerical study on the effects of geometrical parameters and Reynolds number on the heat transfer behavior of carboxy-methyl cellulose/CuO non-Newtonian nanofluid inside a rectangular microchannel

Present work studies the effects of microchannel height and Reynolds number on the temperature distribution behavior, pressure drop, and Nusselt number of a non-Newtonian nanofluid. The nanofluid is an aqueous solution of carboxy-methyl cellulose with a 1 percent volume fraction of copper oxide (CuO) nanoparticle, which is flowed at four Reynolds numbers of 250, 500, 750 and 1000, respectively, inside a rectangular microchannel with different heights size. Three dimensions in the order of H = 1 mm, H = 1.5 mm, and H = 2 mm are used for the microchannel height. Generally, it is concluded that increment of channel height and Reynolds number reduce temperature, whereas they increase heat transfer rate and Nusselt number due to their role in reducing thermal and hydrodynamics boundary layers thickness and flow concentration within the microchannel. Moreover, this phenomenon increases collision between hot and cold fluids due to decreasing their interval layer thickness. Also, increasing Reynolds number amplifies the pressure drop along the microchannel as well as increasing microchannel height. Therefore, it is concluded that the maximum temperature value of 430 K and maximum pressure drop of 7000 Pa have belonged to the case of studies with minimum and maximum microchannel height, respectively. On the other side, the maximum value of temperature is related to the minimum Reynolds number of 250, whereas maximum pressure drop is related to the maximum Reynolds number of 1000.

Improving the structure of two-phase flow meter using feature extraction and GMDH neural network

Determination of the volumetric percentages and type of flow regime in two-phase fluids is a significant parameter in various industries such as oil, gas and petrochemical industries. In current paper, to distinguish this important parameters, the structure consist of one 137Cs source and just one sodium iodide (NaI) detector has been simulated. Three commonly flow regimes including: annular, stratified and homogeneous are simulated in void fraction of 5%–90%. The simulation structure was carried out by the Monte Carlo N Particle X-version (MCNP-X) code to provide the required dataset for extracting the features and using them in the Artificial Neural Network (ANN). The received signal from the detector has many fluctuation, due to the uncertainty of measurements in the MCNPX code. Considering the uncertainty parameter as high-frequency noise and using the Savitzky-Golay filter to eliminate this noise, it has been tried to improve the uncertainty parameter. After denoising the primary signal seven features in time domain were extracted. All the extracted characteristics were considered as the input of the Group Method of Data Handling (GMDH) neural networks. In this research two independent GMDH neural networks were implemented to identify the flow regime and estimate the volumetric percentages. The results indicate that the proposed model has the ability to distinguish the type of flow regimes with 100% precision and determine the volume fraction percentage with the root mean square error of less than 1.11. Reducing the number of detectors, reducing costs, system simplification and increasing the accuracy of two-phase flow meters are the important advantages of this research.

Flexural, Tensile and Compressibility Behavior of Self Compacting Concrete by using Glass Fibers

Fiber Reinforced Self Compacting Concrete” (FRSCC) is composed of cement, different sizes of coarse and fine aggregates, which integrate with fiber. In this current investigation, M40 grade Self Compacting Concrete reinforced with glass fibers has been developed using the Nan Su method. Fresh state and hardened state properties of Glass Fiber Reinforced Self Compaction Concrete are studied for glass fibers of different aspect ratio (875, 1285 & 1714) and percentage of volume fraction (0, 0.25, 0.5, 0.75 & 1). From the investigation carried out it is found that incorporation of glass fibers of aspect ratio 1285 and percentage of volume fraction 0.5 to SCC attains better compressive and flexural strength compared to other mixtures and also incorporation of glass fibers of aspect ratio 1285 and percentage of volume fraction 0.75 to SCC attains better split tensile strength compared to other mixtures.

The Effect of Alkaline Solution of Varying Molarity and Hookedend Steel Fibres on Split Tensile Strength(SPTS)(fct) of Fibre Reinforced Geopolymer Concrete(FRGPC)

This article mainly aims the study the effect of alkaline solution of varying molarity [1]” and the percentage of volume fraction of steel fibres[2]” of 0%, 0.5%, 0.7%, 0.9% and 1.1% (R0, R5, R7, R9 and R11),different ratios of GGBS to Flyash on Split Tensile Strength of GPC is studied. The combination of Sodium Hydraxide (NaoH) of different molarity (8M,10M and 12M) and Sodium Silicate (Na2Sio3) used are alkaline activators. The Modified Binder Index(Bmi) [3]” is introduced to express the effect of Binder Index(Bi) [4]” and hooked end Steel Fibre Effect on Split Tensile Strength (fct) of SFRGPC. In the experimental program total 180 cylinders of its size 100mm dia and 200mm length for each variation were cast and tested after 7days and 28days of ambient curing for average strength. The effect of Molarity, GGBS to Flyash ratio and Steel Fibres on the SPTS (fct) of SFRGPC is presented in this paper.

Effects of Nanoparticle Enhanced Lubricant Films in Thermal Design of Plain Journal Bearings at High Reynolds Numbers

Performance investigation of oil journal bearings is of particular importance given the growing use of them as a support for rotary components in a wide range of industrial machines. Frictional forces and shear stresses, which are proportionate to the velocity of lubricating layers at different points in the bearing space, provide the basis for changing temperature conditions. Various factors such as rotational velocity increase, slip width reduction, and small heat transfer coefficient of lubricant cause intensification of lubricant temperature changes. In the present study, with using computational fluid dynamic (CFD) thermohydrodynamic (THD) numerical simulations, the effect of nanoparticles on the performance features of plain journal bearings is evaluated. Particularly, 3D simulation of a journal bearing is implemented using CFD which considerably improves the accuracy of results, coupled with conjugate heat transfer model for metal parts of bearings. Reynolds equation model is used to calculate the oil-film pressure developed in hydrodynamic journal bearings by applying the nano-based lubricants. The configuration of thrust bearing consists of six pads in this study. In order to reduce the modeling complexity and computational cost and because of the symmetrical geometry of the pads, simulation of a single pad is considered instead of the entire domain. In this study, TiO2 nanoparticle with different volume fraction percentages are used. The parameters that are changed to evaluate the performance of the bearing include volume fraction percentage of the nanoparticle, type of lubricant, and rotational speed. Based on the results, for all different lubricant types, the dissipation power, average shear stress, and temperature rise are increased with augmenting the rotational speed. By increasing the rotational speed from 500 to 1500 rpm, the average shear stress increases by more than 100%, 120%, and 130% for DTE 26, DTE 25, and DTE 24 lubricant types, respectively. Moreover, by increasing the rotational speed from 500 to 1500 rpm, the dissipation power, and temperature rise are increased around 600% and 800%, respectively. Furthermore, increasing nanoparticles volume fraction from 0% to 10%, increases all parameters by approximately 10% for all lubricant types and in all rotational speeds.

Determination of the volume fraction in (water-gasoil-air) multiphase flows using a simple and low-cost technique: Artificial neural networks

The precise prediction of the volume fraction in three-phase flows plays an important role in the petroleum and process industries. In this study, attenuation gamma rays (single pencil beam) and multilayer perceptron neural networks were used to precisely predict the volume fraction percentage in water-gasoil-air three-phase flows. The detection system uses just one 137Cs source (single energy of 662 keV) and one NaI(Tl) detector in order to calculate the transmitted beams. The experimental setup was simulated using the MCNPX code to provide the required data for the neural network. The volume fraction percentage was measured with a root mean square error of 2.48 and a mean relative error percentage of less than 7.08%. The proposed setup is the best and simplest design for reducing radiation hazards and cost.

Processing and investigation of mechanical characteristics on the polydimethylsiloxane/carbon black composites

The mechanical adaptability of elastomers has enormous potential in fields such as energy harvesting, micro electro mechanical system (MEMS), sensor, and actuator. A significant issue is to improve the mechanical features of the elastomeric base material by incorporating an appropriate filler. The elastomer Polydimethylsiloxane (PDMS) is reinforced with carbon black (CB) particles that affect mechanical characteristics (Tensile strength, compressive strength, tear strength, etc) and that have a critical impact on the efficiency of the device. The current research examines the mechanical characteristics of plain PDMS with a concentration of CB filler between 5% and 25%. A solution casting method is used to prepare the composite substrate and investigate the impacts of CB loading performance on tensile, compression, tear, and hardness testing. The outcome shows an improvement in mechanical characteristics due to CB material for Young’s module as 1.64–3.84 MPa, ultimate tensile strength as 1.86–4.8 MPa, 3.67–4.81 MPa compressive module with the same compressive strength up to 40 percent strain. The tear strength of the PDMS/CB composites is improved by ∼111 percent at 25 percent volume fraction of the CB. The composite hardness of PDMS/CB increases by about 30 percent of the plain PDMS material. Continuing with this, Additional mechanical characteristics of PDMS/CB composites on shear and bulk modules are reported.

A simple and inexpensive design for volume fraction prediction in three-phase flow meter: Single source-single detector

The problem of how to correctly predict the volume fraction in three-phase flows in sensitive operational conditions is an important parameter in the oil and petroleum industry. This research presents a new methodology for volume fraction percentage prediction in water-gasoil-air multiphase systems based on transmitted gamma ray method and multilayer perceptron (MLP). The detection system uses an appropriate single source-single detector set-up, consists of a dual-energy gamma-ray source and one NaI(Tl) detector. The experimental setup provides the required data for training and testing the network. Using this proposed method, the volume fraction was predicted in water-gasoil-air three-phase flows with mean relative error percentage (MRE%) less than 4.64% and root mean square error (RMSE) of 1.49. MER% quantities for each phase of water, gasoil and air were calculated 3.72, 4.54 and 5.65, respectively. Also, the RMSE quantities were measured 0.79, 1.46 and 1.98 for water, gasoil and air, respectively. The results revealed that a good agreement is between the predicted volume fraction percentage and actual data due to the comparison of the performance of the proposed method (MLP) and the relationship derived from empirical data. The old systems used were adequately complicated whereas the new design is certainly very simple. Also, radiation safety and shielding conditions ans electronic requirements are optimized. So the cost is minimized as low as possible.

Reliability and sustainability of wire arc additive manufactured plates using ER 347 wire-mechanical and metallurgical perspectives

The steel wall measuring 120 mm in length and 210 mm in height was manufactured by wire and arc additive manufacturing (WAAM) using ER347 wire and gas metal arc welding (GMAW). The mechanical integrity and microstructure of the WAAM treated plate were examined. It was found that the steel plate was well formed, no clear boundaries between the layers were observed, and different thermal history leads to a variety of microstructures. The hardness of the WAAM-processed plate gradually varied from top to bottom and was between 203.5 HV and 248.2 HV. Microstructure of WAAM 347 consists of columnar dendrites and equiaxed dendrite in the multilayer deposition. The percent volume fraction of delta ferrite in the as-deposited WAAM plate was 4.2 and the predicted ferrite number from WRC-1992 diagram is 4.1. The mechanical properties of the welded parts were anisotropic; the sample at 45° orientation has a higher tensile strength compared to 0° and 90° orientation samples. The fractured tensile specimens in the as-deposited state were characterized by dimple-like structures revealing the ductile fracture. SEM line mapping confirms the presence of intermetallic compounds (NbC) in the WAAM 347 plate.

Evaluation of Chronic Subdural Hematoma Volume Calculated via Cavalieri’s Principle

Background: Chronic subdural hematoma (CSDH) is a frequently encountered entity in neurosurgery. The objective of this study was to describe the use of unbiased Cavalieri principle to assess CSDH volume to total brain volume fraction (Percentage) and compare it with the clinical features of the patients. Methods: A total of 33 patients were included in the study. Computed tomography (CT) was acquired from the hospital-imaging database. The ratio of hematoma volume, brain volume, and hematoma volume to brain volume were measured via CT by two clinicians. Measurements were compared with clinical findings. Results: The sample consisted of 22 males and 11 females and mean age 67,27±12,63 years. The measured hematoma volume was 89,78 ± 54,13 cm3, the brain volume was 1329,91 ± 2098,35 cm3 and the percentage volume was 8,14 ± 4,92 cm3. The brain volume values of the cases with impaired consciousness were found to be statistically significant (p <0.05). Conclusion: It should be kept in mind that the bleeding volume of patients with vomiting may be higher.

Precise volume fraction measurement for three-phase flow meter using 137Cs gamma source and one detector

Abstract The ability to precisely predict the volume fraction percentage of the different phases flowing in a pipe plays an important role in the oil, petroleum and other industries. In this research, the volume fraction percentage was measured precisely in water-gasoil-air three-phase flows by using a single pencil beam gamma ray attenuation technique and multilayer perceptron (MLP) neural network. The volume fraction percentage determination in three-phase flows requires least two gamma radioactive sources with different energies while in this study, we used just a 137Cs source (with the single energy of 662 keV) and a NaI detector. Also, in this work, the MLP neural network in MATLAB software was implemented to predict the volume fraction percentage. The experimental setup provides the required data for training and testing the network. Using this proposed method, the volume fraction was predicted in water-gasoil-air three-phase flows with mean relative error percentage less than 6.95 %. Also, the root mean square error was calculated 2.60. The set-up used is simpler than other proposed methods and cost, radiation safety and shielding requirements are minimized.

Pengaruh Kecepatan Pengadukan dan Penambahan Persentase Magnesium terhadap Kekerasan dan Laju Aus Komposit Matrik Logam dengan Metode Stir Casting

The cahracteristic of MMCs with stir casting method are influenced by speed of the stirrer, temperature process, percentage of magnesium and volume fraction. This research is stressed on the effect speed of stirrer and percentage of magnesium to characteristic of MMCs (Al/Al2O3) as a product of stir casting process. Materials used in this research are powder (Al2O3), Aluminium ingot and Al-31,3% Mg ingot as wetting agent, and Argon as gas of inert. The parameters used in MMCs manufacturing are stir casting with speed of stirrer 520 and 1510 rpm, at temperature 550°C and percentage of magnesium of 2, 5, 8, 10, 15% wt (material balance process). From this research result is obtained that high of speed stirrer and held up of magnesium will improve characteristic from metal matrix composite. At this research is obtained by speed of stirrer 1510 rpm and 15% Mg have composite optimum characteristic of hardness 98 HBN and wear resistance 3,59 × 10-6/mm3/mm of 1510 rpm and 10% Mg.

Effect of steel fibers on the performance of concrete made with recycled concrete aggregates and dune sand

Abstract This paper aims to develop and evaluate the performance of steel fiber-reinforced concrete made with recycled concrete aggregates (RCA) and desert dune sand. Different fresh and hardened properties of RCA concrete mixtures with and without steel fibers were evaluated and compared with those of a mixture made with natural coarse aggregates (NA). Test parameters included the RCA replacement percentage and steel fibers (SF) volume fraction (vf). Test results showed that the substitution of 30% of NA with RCA in plain concrete mixes did not reduce the design cylinder compressive strength (f′c), whereas the use of higher percentages of RCA replacement compromised the fresh and hardened properties of the concrete. The addition of SF significantly reduced the adverse effects caused by the inclusions of RCA in the mixes. RCA-based concrete mixtures having 70 and 100% RCA replacements could be produced with f′c values comparable to that of a NA-based concrete, when minimum vf values of 1, and 2% were added, respectively. The RCA replacement increased the water absorption and sorptivity but decreased the ultrasonic pulse velocity, bulk resistivity, and abrasion resistance. The addition of SF improved the hardened properties of RCA-based concrete mixes to an extent of exceeding some of those of the NA-based counterpart, as in the case of abrasion resistance. Analytical regression models were introduced to correlate different concrete properties to the 28-day cylinder compressive strength.

Synthesis of ferrofluids using a chemically induced transition method and their characterization

Using an altering chemically induced transition route, magnetic nanoparticles as well as nanoparticles modified with oleic acid have been prepared. The modified nanoparticles have been used to synthesize a high-quality kerosene-based ferrofluid, in which the mass fraction percentage of particles consisting of a γ-Fe2O3 core and an oleic acid coating, ϕm, amounted to 55%. Ferrofluids having lower concentrations of particles were obtained by diluting the mother ferrofluid. Magnetization measurements showed the as-synthesized ferrofluids to have excellent dispersity of the particles and field-induced inter-particle interactions. Optical transparency measurements confirmed that the ferrofluids showed a sensitive field-induced effect of chain-like aggregation, with redispersion of the particles after removing the magnetic field. According to results concerning both particle structure and ferrofluid density, the volume fraction percentage of particles, including both the γ-Fe2O3 core and the oleic acid coating, ϕ′v, as well as that of the γ-Fe2O3 alone, ϕv, can be deduced.

Effect of Strain Induced Martensite Reversal on the Degree of Sensitization of Metastable Austenitic Stainless Steel

Effect of reversion of strain induced martensite on degree of sensitization (DOS) of Cr-Mn Austenitic stainless steel (ASS) have been examined. The martensite reversion is known to be effective in refining the grain size of metastable ASS. However, martensitic reversal takes place only after severe cold rolling reductions. In this study, the effect of degree of cold rolling and subsequent thermal ageing on the microstructure, mechanical, and sensitization properties of a metastable Cr-Mn ASS was investigated. Samples were cold worked (25% and 45%) and then thermal aged at different temperature of 700°C and 900°C for 2 hrs. Microstructures were subjected to optical microscopy. Microstructural study shows that with increasing thermal ageing temperature, strain induced martensite undergoes reversal to austenite and is associated with grain refinement. XRD analysis has revealed that at 25% cold work, volume fraction of martensite was 24%, and as cold work was increased to 45%, the volume fraction of martensite was 42%. Whereas after thermal ageing at 700°C, part of strain induced martensite undergo reversal to austenite and only 18% martensite is left in the matrix. On thermal ageing at 900°C, only 2% strain induced martensite was left in the matrix. Hardness also follows the same trend as observed for volume fraction of martensite during cold work and subsequent thermal ageing. As the cold work percentage increases, hardness and volume fraction increases but as thermal ageing temperature increases, both hardness and volume fraction of martensite decrease rapidly. Degree of sensitization (DOS) decreases with increasing thermal ageing temperature.

Characterization of Active Carbon from Coconut Shell using X-Ray Diffraction (X-RD) and SEM-EDX Techniques

Activated carbon is produced from the coconut shell through physical and chemical activation. The pyrolysis method was employed in this research for physical activation at an optimum temperature of 600oC and 1,000oC, for chemical activation immersed using 10% Na2CO3 activating agent. This research has produced two samples, namely the physical activation of 1,000oC and the physics-chemical activation of Na2CO3. The X-Ray Diffraction (X-RD) spectrum of activated carbon in the samples 1,000oC and Na2CO3 contained silicate minerals, iron ore and quartz, respectively, and it showed the formation of carbon and graphite structures in the hkl (002) and (100) planes. Through Scherrer’s method, the average size of the Na2CO3 crystals sample is 15.03 nm and the sample crystal sample of 1,000oC is 54.53 nm; the size of the Nano-scale crystals was formed when the temperature increases ≥ 600° C. The X-RD resulted the percentage of elemental content carbon phase volume fraction (Fv) and impurity (I) in the 1,000oC sample of 75.61%, 24.39% and the Na2CO3 sample of 77.87%, 22.13% . These results indicate that the carbon content in chemical activation is much better than the physics activation. SEM results with magnification of 5,000x, it is very clear the porosity formed of the 10 μm picture size are 0.8 μm in Na2CO3 sample and 1.00 μm in 1,000oC sample.

Experimental Investigations on Basalt Fibre-Reinforced Concrete

Fibres are used in concrete to improve its structural integrity. Nowadays, among all basalt fibres, an inert mineral fibre is gaining more importance due to its exceptional properties, which include resistance to corrosion and low thermal conductivity. It also improves tensile strength, flexural strength and toughness of concrete. It can be used to extend the life of important concrete structures such as nuclear power plants, highways, bridges and runways. Basalt fibre in concrete is still an exploratory area due to limited studies. Therefore, a systematic study on basalt fibre-reinforced concrete was carried out with percentage volume fraction of fibre 0.50 (13.0 kg/m3), 0.75 (19.5 kg/m3) and 1.00 (26.0 kg/m3). The increase in compressive, splitting tensile and flexural strength is in the order of 26.79, 42.71 and 44.06%, respectively, for 0.50% dosage of basalt fibre as compared to control concrete. In addition, basalt fibre is found to be amorphous and hydrophilic in nature.

Enhanced photocatalytic activity and enormous dielectricity of α-Fe2O3/reduced graphene oxide nanocomposites

Nanocomposites of single-phase iron oxide (α-Fe2O3) and reduced graphene oxide (rGO) with different volume fractions have been prepared by chemical route. Structural, morphological and spectroscopic characterizations have been performed by XRD, FESEM, TEM, XPS and Raman studies. Photocatalytic activity of these composites has been investigated by the degradation of methylene blue dye under visible light irradiation. The activity is found to depend on the percentage of volume fraction (vf) of rGO in the composite. At \( v_{\text{f}} = 10.3, \) the photocatalytic activity becomes maximum and the degree of degradation of MB is found to be ~ eight times to that of pure α-Fe2O3. The enhanced photocatalytic activity may be attributed to the prolonged lifetime of electron–hole pair produced in α-Fe2O3. The stability and reusability of photocatalyst during photocatalytic reaction, which is a crucial factor for the practical applications, is also verified. At this particular volume fraction of rGO, i.e., vf = 10.3, the nanocomposite exhibits huge dielectric constant ~ 2950 times to that of pure α-Fe2O3 along with moderate dielectric loss enabling it a potential candidate for charge storage device.

Quantitative MRI of Perivascular Spaces at 3T for Early Diagnosis of Mild Cognitive Impairment.

The limitations inherent in the current methods of diagnosing mild cognitive impairment have constrained the use of early therapeutic interventions to delay the progression of mild cognitive impairment to dementia. This study evaluated whether quantifying enlarged perivascular spaces observed on MR imaging can help differentiate those with mild cognitive impairment from cognitively healthy controls and, thus, have an application in the diagnosis of mild cognitive impairment. We automated the identification of enlarged perivascular spaces in brain MR Images using a custom quantitative program designed with Matlab. We then quantified the densities of enlarged perivascular spaces for patients with mild cognitive impairment (n = 14) and age-matched cognitively healthy controls (n = 15) and compared them to determine whether the density of enlarged perivascular spaces can serve as an imaging surrogate for mild cognitive impairment diagnosis. Quantified as a percentage of volume fraction (v/v%), densities of enlarged perivascular spaces were calculated to be 2.82 ± 0.40 v/v% for controls and 4.17 ± 0.57 v/v% for the mild cognitive impairment group in the subcortical brain (P < .001), and 2.74 ± 0.57 v/v% for the controls and 3.90 ± 0.62 v/v% for the mild cognitive impairment cohort in the basal ganglia (P < .001). Maximum intensity projections exhibited a visually conspicuous difference in the distributions of enlarged perivascular spaces for a patient with mild cognitive impairment and a control patient. By means of receiver operating characteristic curve analysis, we determined the sensitivity and specificity of using enlarged perivascular spaces as a differentiating biomarker between mild cognitive impairment and controls to be 92.86% and 93.33%, respectively. The density of enlarged perivascular spaces was found to be significantly higher in those with mild cognitive impairment compared with age-matched healthy control subjects. The density of enlarged perivascular spaces, therefore, may be a useful imaging biomarker for the diagnosis of mild cognitive impairment.