Air Content Research Articles

Water sorptivity prediction model for concrete with all coarse recycled concrete aggregates

This paper examines the water sorptivity of recycled aggregate concrete (RAC) and shows how sorptivity can be predicted using electrical resistivity as the main predictor. The measurements in 48 RAC specimens show that RAC has higher water sorptivity and lower electrical resistivity than regular concrete. RAC sorptivity and rate of saturation prediction models were developed using multiple linear regression analysis. The prediction models include electrical resistivity, percent volume of coarse recycled concrete aggregates, and air content of residual mortar as explanatory variables. A graphical calculating device based on the sorptivity regression models was also created.

Study on the Compressive Stress–Strain Curve and Performance of Low-Slump Polypropylene Fiber Concrete after High Temperature

This study aims to investigate the effect of high temperature on the mechanical properties of low-slump polypropylene fiber (PPF) concrete, and tests the tensile and compressive properties of 204 groups of low-slump PPF concrete with eight different dosages and four different lengths at normal temperature and after high temperature. The results of the compressive test showed that PPF can significantly improve the mechanical properties of concrete after high temperature when the fiber content is small, and the compressive strength of low collapse polypropylene fiber concrete after high temperature showed a tendency to rise and then fall at the same temperature with an increase of the fiber admixture. When the fiber content was 0.5 kg/m3, the compressive strengths of 3 mm, 9 mm, 15 mm and 19 mm reached their maxima, which were 9.65%, 11.33%, 7.90% and 2.87% higher than that of ordinary concrete, respectively. With an increase in fiber length, the effect of PPF on the compressive strength of concrete is not obvious. PPF at high admixture further increases the pore and air content in concrete, which decreases the compactness of the concrete, thus leading to a decrease in the compressive strength of the concrete. When the temperature was 800 °C and the fiber admixture was 5.0 kg/m3, the compressive strength of PPF concrete with different lengths reduced by 17.83%, 17.27%, 22.59% and 23.92%, respectively, compared to normal concrete. In addition, according to the results, the optimal combinations of strength at room temperature and after high temperature were 3 mm fiber length and 1.0 kg/m3 dosing and 9 mm fiber length and 0.5 kg/m3 dosing, respectively, which increased the compressive and tensile strengths by 17.15% and 25.72% at room temperature and by at least 6% and 20% after high temperature, compared to the concrete without fiber dosing. Moreover, the stress–strain constitutive equations of PPF concrete at normal temperature and after high temperature were established, which can be used for finite element simulation and related mechanical analysis of PPF after high temperature.

Status Mutu Kualitas Udara Ambien Pada Beberapa Kota Besar di Papua Menggunakan ArcGIS

The increase in population in recent years has affected the utilization of facilities and infrastructure, including the use of vehicles. For the past 10 years, the population in Papua has increased by around 4.13% per year, resulting in the need for daily mobility to increase. The high mobility demand in Papua could affect the increase in pollution, thus affecting the air quality. Exposure to pollutants in ambient air and environmental noise in the long term will have an impact on human health. Therefore, in this study, we analyze the current conditions of air pollution parameters in several major cities in Papua, such as Jayapura, Merauke, Sentani, and Timika. The method used is a survey. Environmental parameters measured were air content of SO2, NO3, PM 10, PM 2.5, HC, O3, CO, dust, Pb, noise, and The Air Pollutant Standard Index (ISPU) value. Observational data obtained were analyzed and displayed using the ArcGIS program. The parameters for determining the location of sampling points are densely packed highway areas, industrial areas, residential areas, and offices. The results of the study indicated that the ambient air quality in all study sites is below the required quality standard. While the results of environmental noise that exceed the highest quality standards located in specifics area on each study site are as follows, Merauke at PLTD Merauke I PT. PLN Persero with 81.24 dB(A), Sentani at Sentani City Square Roads with 70.2 dB (A), Mimika at Perumahan Pemda SP-2 with 65.30 dB(A), and Sentani at Kantor Bupati Jayapura with 64, 54 dB (A). However, the ISPU value for pollutant substances is still in the range of 0-50, which means that the air quality category is very good to carry any outdoor activities, and does not have any negative impact on humans, animals, or plants.Key words: air quality; noice; ISPU; Papua.

New solutions for an old problem : Current developments in oral contrast agents

Several radiological societies in Europe have so far spoken out in favor of MRI of the small intestine over CT, since MRI is said to provide more detailed image information. Due to the limited availability of MRI machines, long waiting times arise for many patients who clinically require small bowel imaging. These circumstances guided our search for an improved CT technique that would provide scans that mimic the image impression of T1 sequence in MRI, i.e. with IV contrast-enhanced intestinal wall versus low/no signal lumen. The oral use of fat or oil is poorly tolerated by patients, as is the placement of anaso-duodenal tube for air insufflation. We have now succeeded in creating afoamy drink with 44% air content, which is kept stable by protein together with buffers, and can be easily administered orally. CT with the Lumentin® beverage as bowel filling agent has been tested on healthy adult volunteers; oncology patients; and Crohn's disease patients who, for comparison, also underwent MRI of the small bowel with conventional oral contrast. The results so far with Lumentin® show avery good distribution throughout the entire small intestine with good lumen distension, images with strongly enhanced contrast of the intestinal mucosa, and lesions that are detected at the same or increased frequency as compared with MRI. Side effects were few and mild, and overall fewer than with commonly used oral agents. Lumentin's foamy consistency was unfamiliar to afew patients, but it wasn't difficult to drink. The new and innovative luminal HU-negative contrast agent Lumentin® improves the diagnostic CT image quality. In addition, Lumentin® experimental MRI tests have provided promising results, which are currently leading to further clinical MRI studies.

Characterization of rock glaciers environments combining structurally-coupled and petrophysically-coupled joint inversions of electrical resistivity and seismic refraction datasets

The degradation of mountain permafrost is well documented at many Alpine sites. Geophysical techniques have been intensively used to monitor these sites, since permafrost degradation is not only a proxy of climate change and global warming but also a possible source of slope instabilities and triggering of mass movements. While the use of non-invasive geophysical techniques is promising, the interpretation of different geophysical results can introduce ambiguities in defining the investigated subsoil and often does not lead to a quantitative estimation of the internal permafrost constituents (rock matrix, ice, liquid water and air contents). To overcome these limitations, we applied an optimized joint inversion approaches of electrical resistivity and refraction seismic tomography datasets collected at two Swiss rock glaciers (Schafberg - Canton Grisons, and Ritigraben - Canton Valais). Firstly, to improve the structural interpretation of the frozen near subsurface, we performed a structurally coupled cooperative joint inversion, optimizing the coupling parameters. Subsequently, we used the petrophysical joint inversion to quantify the composition of these mountain permafrost substrates, optimizing the numerical and petrophysical parameters. The obtained results agree with field observations and the borehole data collected at these two sites, opening new perspectives for the future quantitative monitoring of permafrost constituents. Plain language summaryIncreasing mean annual temperatures over the last decades has led to glacier melt and permafrost thawing. The degradation of glaciers is easier to quantify as they are visible on the surface, as opposed to permafrost which is found in the subsoil and must therefore be studied with direct drilling techniques or with non-invasive geophysical methods. Drilling investigations are expensive and complicated to perform in high mountain environments and only provide 1D information. Geophysical surveys can be used to quickly and economically characterize larger areas. Since permafrost thawing is a risk factor in high mountain environments (inducing e.g. instability of infrastructure, or triggering rock falls and landslides), it is important to have reliable geophysical techniques to study these environments. In this work, we propose an optimization of two different data analysis processes, applied to geoelectrical and seismic measurements, to better define the structure and composition of two ice-rich mountain permafrost sites in the Swiss Alps.

Fundamental study on the growth process of interfacial microbubbles in an air-supersaturated solution

Interfacial microbubbles widely exist and play important roles in nature and industries, while their growth process remained unknown in many aspects. In this study, the interfacial microbubbles are created in an air-supersaturated solution utilizing a sudden drop of ambient pressure, and the effects of different influential parameters on the growth process of interfacial microbubbles were studied by a self-made observation system. The investigations confirmed that the growth process of interfacial microbubbles under all conditions had experienced three stages, including the floating stage, transition stage and expansion stage. The experimental results also show that the magnitude of depressurization amplitude, surface wettability, surface roughness, dissolved air content, and solution surface tension have significant effects on the nucleation and growth of interfacial microbubbles. In addition, the modified diffusion theoretical model of dissolved air was successfully used to predict the changes in contact angle and bubble radius for interfacial bubbles during the growth process.

Rancang Bangun Oven Pengering Lidi Sawit Dengan Sistem Double Blower

The process of drying palm sticks carried out by umkm in Kampar Regency, precisely in the Terentang mine, still needs to be solved in the drying process, which only has sunlight and changes in hot weather in the quality drying palm sticks. Therefore, an oven is designed to improve the quality of drying palm sticks using a double blower system and a branched pipe. This oven is manufactured for an open iron drying room measuring 3x3 cm with volume dimensions of 100 cm3, then for the heating room using a hollow iron measuring 3x3 cm with dimensions of length 50 cm, width 50 cm, and height 50 cm. Heat flow pipe using a pipe of 2 inches along the 800 mm and connected using a branched pipe 50 mm long with a pipe size of 1 inch as much as 4 sections that lead to each rack in the oven chamber. Based on the calculation of the design capacity of this palm stick drying oven, the total capacity of this oven is 28.8 kg on each shelf. However, from experiments that have been carried out with the drying process of palm sticks at full capacity, it is measuring the water content of each shelf is uneven. The bars on each frame and the rods in the middle pile do not experience differences in air content because the hot air obtained is less when compared to the top bundle of posts and the bars at the bottom.

Effect of Maximum Aggregate Size and Powder Content on the Properties of Self-compacting Recycled Aggregate Concrete

The utilization of recycled aggregates and various industrial by-products is considered a sustainable strategy in the concrete industry. In this study, the effect of the maximum size of recycled coarse aggregate and the cementitious binder content on fresh and hardened properties of self-compacting concrete was investigated. Self-compacting concretes with maximum aggregate sizes of 9.5 mm, 12.5 mm, and 19 mm were prepared at water-to-binder ratios of 0.39, 0.42, and 0.45, respectively. For all mixtures, 100% recycled aggregate was used as coarse aggregate and 60% of cement was replaced by industrial by-products, i.e., fly ash and ground granulated blast furnace slag. The tests included slump flow, air content, hardened density, compressive strength, elastic modulus, and splitting tensile strength. The results showed that the increase in maximum aggregate size and binder content tended to improve both fresh and hardened properties of self-compacting concrete.

Dielectric Properties of Healthy Ex Vivo Ovine Lung Tissue at Microwave Frequencies

Knowledge of dielectric properties of lung tissue is fundamental for the improvement of lung disease diagnostics and therapeutic solutions (e.g. microwave imaging and microwave thermal ablation treatment). Although lung disease rates are increasing, lung tissue remains one of the least characterized tissues due to its heterogeneity, variability in air content, and handling difficulties. In this work, dielectric properties of ex-vivo ovine lung tissue samples were measured in the frequency range 500 MHz – 8 GHz, together with measurements of sample density (air content). Different Cole-Cole models were applied to the measured dielectric properties values. The best fitting model was chosen, and results were compared with available literature. Furthermore, the dielectric property measurements were correlated with the air content of the samples. Updated Cole-Cole models for lung tissue of different density is provided in the 500 MHz – 8 GHz range. The existence of air content threshold in lung is shown. Below this limit, the properties begin to change drastically with the change in density.

Chalcedonite aggregate in lime mortars: Assessment of strength, microstructure, and durability

The constructions of historic buildings are on ground and sub-ground level often affected by various salts leeching in the constructions from surrounding environment due to non-existent or non-functional ground-water insulation. The salts dissolved in water are transported through capillary system of masonry and cause severe problems at air-construction interface where the water evaporates into the environment and salts accumulate in the outer-most layer destroying it in the process by the crystallization. To improve the durability of repair mortars and their ability to accumulate salts lightweight porous aggregate is used. This study focuses on the use of chalcedonite aggregate in such materials. Mortars based on aerial and natural hydraulic lime are prepared and the siliceous aggregate is replaced by chalcedonite sand. Fresh state properties of mortars likely to affect microstructure and/or durability e.g. air content in fresh mortar are determined. Flexural and compressive strength are studied at the ages of 28, 56, 90, 180, and 365 days, additionally at 90 days microstructural characteristics, durability to freeze–thaw cycles and salt crystallization resistance are studied. The use of highly porous aggregate leads to significant increase in amount of mixing water needed to achieve the same workability, while air content in fresh mortar and water retention value are only mildly affected. The substitution of aggregate leads to improvement in flexural strength however, compressive strength is decreased. The incorporation of lightweight porous aggregate causes significant increase in total open porosity of the mortars, their water absorption as well as increase in capillary water transport. Even though the significant increase in hygric properties, the durability to freeze–thaw cycling also increases. The improvement in salt crystallization resistance is observed mainly in the case of sulfate attack with only minor improvements in the solutions of nitrates and chlorides. The mortars with chalcedonite aggregate show results favourable for their utility as repair mortars, mainly in damp buildings, where the fast capillary water transport is highly beneficial.

Recycled Concrete Aggregates: A Promising and Sustainable Option for the Construction Industry

The recycling of locally collected concrete waste is being promoted toward reducing the carbon footprint. In the preparation of concrete, recycled concrete aggregates (RCA) are encouraged instead of natural aggregates (NA), as they can help reduce the consumption of virgin materials, the extraction and transportation of which can be costly and environmentally damaging. In this context, we conducted an experimental study on various concrete mixes to evaluate the effect of using RCA instead of NA on the physical and mechanical properties of fresh and hardened concrete. The main novelty of our study lies in meeting one of the principles of circular economy, i.e., reducing the carbon footprint, by recycling concrete waste collected locally. We prepared and investigated test specimens containing 0%, 20%, 40%, and 60% of fine and coarse recycled concrete aggregates. Results for fresh concrete were determined for temperature, consistency, air content, and density, while on the other side, in hardened concrete, results were determined for compressive strength, tensile splitting strength, and density. All results were determined experimentally and then compared. Our results showed that, with the use of RCA in the concrete mix, construction companies can significantly reduce their carbon footprints and help conserve natural resources. RCA can help create a more sustainable and affordable construction industry and is better suited to meet future challenges. Our study can serve as a basis for advancing the application of RCA in the preparation of concrete for sustainable construction. Doi: 10.28991/HEF-2023-04-02-03 Full Text: PDF

鋼繊維補強コンクリートにおける引張靭性の評価に関する実験的研究

The quantitative evaluation of tensile ductility of steel fiber reinforced concrete (design strength 30-60 MPa) containing 0.5-1.0% steel fiber with hooks at the ends was investigated. The maximum value of tensile stress after cracking in the tensile softening curve could be roughly evaluated by the linear formula of compressive strength. The influence of aggregate type, coarse aggregate content and air content on the formula was relatively small. Similarly, the average value of tensile stress up to 1 mm crack width in the tensile softening curve could be roughly evaluated by the linear formula of compressive strength.

Svojstva svježeg i očvrsnulog betona s dodatkom crvenog mulja i silicijske prašine

In recent years, various studies have been conducted on the utilisation of bauxite residue from alumina production (known as red mud) in the construction industry. It is particularly noteworthy as a partial replacement for cement in concrete because of its favourable chemical composition. In this study, red mud and silica fume were investigated as partial replacements for cement in concrete. Five mixtures were tested. Herein, cement was replaced with red mud at 0, 5, 10, 15 and 20 % by cement mass. Furthermore, cement was replaced by silica fume at 10 % by cement mass in all the mixtures. The workability, bulk density, and air content were tested to evaluate the properties of the fresh concrete. The bulk density, water absorption, compressive strength, splitting tensile strength, water penetration, and freeze–thaw resistance were tested to evaluate the properties of the hardened concrete. The results indicated that for a low red mud content, reasonable fresh and hardened concrete properties were achieved.

Comparative Study of the Lightening of Concrete Through the Use of Recycled Tire Rubber and Expanded Clay Aggregate

Abstract The waste of tire rubber is characterized by the generation of huge amounts, which is annually discarded. This waste causes problems for human health and the environment. Thus, the valorization of recycled tire rubber in concrete production is considered as an alternative and sustainable solution. This experimental work is a comparative study, which aims to investigate the possibility of using recycled tire rubber as a fine aggregate in the production of lightweight concrete. To achieve this objective, two types of lightweight concrete containing (35, 70 and 100%) of expanded clay and (5, 10 and 15%) of recycled tire rubber as a fine aggregate were produced. Their fresh properties were investigated using slump, density and air content tests, while the hardened properties were investigated by compressive strength, flexural strength, ultrasonic pulse velocity, and water absorption tests. The results obtained showed that the utilization of both expanded clay aggregate and recycled tire rubber leads to a reduction in density and mechanical strength but increases the porosity of lightweight concrete. However, the lightweight concrete containing the expanded clay aggregate had a higher efficiency factor than those containing recycled tire rubber.

Experimental study on frost resistance of hybrid fiber fly ash concrete

Based on the orthogonal test, the optimized ratio of hybrid fiber fly ash concrete prepared with different volume admixtures of polypropylene fiber and polyacrylonitrile fiber, and different lengths, was obtained, and its frost resistance was evaluated in terms of mass change, dynamic elastic modulus, compressive strength, and splitting tensile strength before and after water and salt freezing. Then, the damage mechanism was discussed by combining the pore structure and SEM analysis. The results show that the tensile strength and relative dynamic elastic modulus of specimens after the water freezing cycle are better than those after the salt freezing cycle with the same number of freeze-thaw cycles, and the mass loss rate is less than that of the salt freezing cycle; the compressive strength and the splitting tensile strength of hybrid fiber fly ash concrete increased by 8.5% and 9.5%, and 46.8% and 12.1%, respectively, after 60 times of water freezing and salt freezing cycles compared with the benchmark fly ash concrete. As the number of freeze-thaw cycles increased, the pore air content and the frequency of large pores increased and the frequency of small pores decreased; in terms of the pore distribution of concrete, the distribution of pore structure was more reasonable for water freeze cycle relative to salt freeze cycle and for hybrid fiber fly ash concrete relative to the base fly ash concrete. Thus, it can be found that hybrid fibers incorporated into concrete can reduce the damage to the concrete interior by the freeze-thaw cycle and significantly improve the frost resistance of concrete.

ИССЛЕДОВАНИЕ МЕТОДА БЛИЖНЕПОЛЬНОЙ СВЧ ТОМОГРАФИИ ПАРАМЕТРОВ ЛЕГКИХ

The results of theoretical and experimental studies of near-field microwave tomography of inhomogeneities in the parameters of relative blood content and air filling of the lungs are presented. Methods and algorithms for solving inverse problems of 3D tomography of the mentioned parameters of the lungs are proposed based on the data of pulse and multifrequency multisensory measurements of the scattered signal, as well as on the basis of the multi-position application of the previously developed 1D tomography (profiling) method. An experimental study of this method was carried out: based on the data of sequential bistatic measurements of the parameters of a scattered ultra-wideband pulse signal in a two-dimensional (square) region of the chest, a three-dimensional tomographic distribution of air content in the lungs in the inhalation phase was obtained.

PENGARUH PEMBERIAN BIOCHAR DAN PUPUK KANDANG AYAM TERHADAP KADAR AIR DAN BEBERAPA SIFAT KIMIA TANAH PESISIR SERTA PERTUMBUHAN TANAMAN SAWI

Southeast Sulawesi has a coastline length of 1,740 km, but the community has not made optimal use of the coastal land, especially for agricultural activities. The purpose of this study is to determine the effect of applying biochar and chicken manure on water content and some chemical properties of coastal soils, to determine the effect of biochar and chicken manure interaction on the growth of mustard plants on coastal soils and find out better doses of biochar and chicken manure on the growth of mustard plants. This study used a Randomized Block Design (RBD) with a factorial pattern consists of two factors, namely biochar B0 = 0 g polybag-1, B1 = 75 g polybag-1 equivalent to 30 t ha-1, B2 = 150 g polybag-1 equivalent to 60 t ha-1 and chicken manure which is P0 = 0 g polybag-1, P1 = 75 g polybag-1 equivalent to 30 t ha-1, P2 = 150 g of polybag-1 is equivalent to 60 t ha-1. Observed variables of moisture content, some chemical properties of the soil as well as plant height and number of leaves. The results showed that the application of biochar and chicken manure was able to increase the air content, pH, Organic-C and total-N. In the B1P1 treatment, the interaction effect on the height and number of mustard leaves and the dose of fertilizer that gave a better effect than other treatments, namely biochar 75 g polybag-1 or equivalent to 30 t ha-1 + chicken manure 75 g polybag-1 or equivalent to 30 t ha-1

NSCLC patients with a changing T grade after operation may represent a special subset of tumor staging.

There is consensus that postoperative adjuvant therapy is not recommended in patients with stage 1a non-small cell lung cancer (NSCLC). Meanwhile, it is still controversial whether postoperative adjuvant chemotherapy is recommended for NSCLC patients with T2aN0M0 (stage 1b). In some patients with stage 1b NSCLC without pleural invasion, tumor diameter was measured between 3 and 4cm by preoperative imaging and less than 3cm by postoperative pathology specimens. TNM staging in such patients is both radiologic stage 1b and pathologic stage 1a. Thoracic surgeons are often confused about whether such patients with NSCLC will require subsequent treatment and how the survival prognosis for this group of patients will be. All data of radiographic TNM stage 1b patients who underwent radical R0 resection at the department of thoracic surgery, the First Affiliated Hospital of Soochow University between January 2013 and July 2017 were retrieved, and 208 patients were finally included in the study. Clinical data, including imaging data, pathology data, were obtained by reviewing the patients' electronic medical records. Disease-free survival (DFS) and overall survival (OS) were obtained by telephone interview. Statistical analysis was performed using SPSS (SPSS 26.0 for windows, SPSS). A total of 208 patients were included in this study, 61 patients with T-stage migration (observation group) and 147 patients without T-stage migration (control group). There were significant statistical differences between the two groups in terms of preoperative FEV1/FVC and tumor diameter (specimens, CT and 3-dimensional measurements). Logistic regression results showed that lower FEV1/FVC and smaller CT measurements would make the patient's T stage more likely to migrate. Bland-Altman plots showed that tumor length measured by imaging was significantly higher than that measured by pathological specimens. Taking DFS as the outcome, the survival curve of the observation group was significantly better than that of the control group. Similarly, there was a significant difference in OS between the two groups. For NSCLC patients whose preoperative imaging evaluation was stage 1b (tumor diameter more than 3cm, no main bronchus, pleura, no atelectasis), the presence of lung tissue with smaller tumor diameter and/or higher air content may indicate that the postoperative pathological staging may be changed to stage 1a (tumor diameter less than 3cm). These patients had better survival prognosis than those who did not undergo TNM stage change and were diagnosed with stage 1b non-small cell lung cancer before and after surgery.

Use of fly ash and quarry waste for the production of the controlled low strength material

This study investigates the potential of utilizing quarry waste and fly ash in the production of controlled low-strength materials (CLSM). Fly ash and quarry waste were mixed in various proportions and the properties of the mix were studied in both fresh and dry states. Cement in low proportions was used as a binder. Flowability, bleeding, density, settlement, air content, pH, and electrical resistivity of the mix was studied in their fresh state. The flowability of the mix was enhanced by the addition of quarry waste. However, incorporating higher amounts of quarry waste caused the mix to exhibit more bleeding, leading to greater settlement. Increasing the concentration of cement was found to mitigate bleeding in the mix. The corrosivity of the mixture was found to be in the permissible limits for use as an excavatable material in utility fills. Unconfined compressive strength, water absorption, density, SEM, and XRF analysis were performed on hardened samples. Unconfined compressive strength tests were performed on the various mix proportions of the samples at 1, 7, 14, and 28 days. The CLSM samples were found to have a low strength of 0.08 to 0.35 MPa at 28 days and hence suitable for use as an excavatable material. SEM analysis revealed that the C-S-H gel was the chief component that contributed to the strength gain of the mixture with time.

Fabrication of Multiphase Liquid Metal Composites Containing Gas and Solid Fillers: From Pastes to Foams

Gallium-based liquid metals (LMs) are suitable for many potential applications due to their unique combination of metallic and liquid properties. However, due to their high surface tension and low viscosity, LMs are challenging to apply to substrates in useful shapes, such as dots, wires, and films. These issues are mitigated by mixing the LMs in air with other materials, such as mixing with solid particles to form LM solid pastes or mixing with gases to form LM foams. Underlying these deceivingly simple mixing processes are complex and highly intertwined microscale mechanisms. Air microbubbles are inevitably incorporated while making LM pastes, making them partly foams. On the other hand, for foaming of the LM to occur, a critical volume content of solid particles must be internalized first. Consequently, both LM pastes and foams are multiphase composites containing solid and fluid microcomponents. Here, we systematically study the impact of the mixing procedure, solid particle size, and volume fraction (SiO2) on the air content of the multiphase LM composites. We demonstrate that decreasing the particle size and increasing their volume fraction substantially decrease the composite density (i.e., increases air entrapment). The foaming process can also be enhanced with the use of high-speed mechanical mixing, although leading to the formation of a more disordered internal structure. In contrast, manual mixing with larger microparticles can promote the formation of more paste-like composites with minimal air content. We explain the microscopic mechanisms underlying these trends by correlating macroscopic measurements with cross-sectional electron microscopy of the internal structure.