Product Size Distribution Research Articles

Enhancing energy release and controlled combustion of B-based MICs by the synergistic effect between polyvinyl pyrrolidone and nitrocellulose

To enhance energy release of boron-based metastable intermixed composites (MICs), a series of B-based MICs were constructed successfully by a facile one-step sol-freeze-drying (SFD) method, where copper oxide (CuO) was employed as oxidant. The structure, morphology, chemical state and specific surface area of B-based MICs were investigated by several characterization technologies, and their reactivity and combustion performance were further studied by various experimental tests. The results reveal that B and CuO nanoparticles were dispersed evenly on a nest network braided by the molecular interaction between polyvinyl pyrrolidone (PVP) and nitrocellulose (NC), and the constant volume combustion heat of B-based MICs even reaches 8956.6 ± 76.6 J·g−1 when PVP (1.25 wt%) and NC (5.0 wt%) were added into B/CuO. The heat value is about 1.7 times as big as pristine B/CuO (5345.5 ± 36.1 J·g−1) and approaches to that of raw B NPs (10335.5 ± 507.8 J·g−1). Moreover, the condensed phase residues of three composites were confirmed to be Cu and Cu2O, while the smallest particle size distribution of product proves that the combustion of B/CuO/NC(NC: 5.0 wt%, PVP: 1.25 wt%) is most complete. So the unique nest network can eliminate particle aggregation, shorten the transfer distance of mass and heat and improve the “solid − solid” thermite reaction. This work will provide a new strategy for promoting the application of boron

Determination of the Radon Progeny Activity Size Distribution in Laboratory Conditions

Knowledge of the active size distribution of radon daughters is one of the main parameters for determining the effective dose from inhalation of short-term radon decay products. However, this parameter is crucial for accurately determining an effective dose; there are currently very limited possibilities for determining it. This paper describes the laboratory validation of a method for determining the activity size distribution of radon decay products using the Dekati ELPI+ cascade impactor and the Graded Screen Array Diffusion Battery (GSA DB). Using nuclear track detectors placed on individual impaction plates of the cascade impactor, the equivalent equilibrium activity concentration of individual size classes can be determined in the range from 17 nm to 10 μm. A diffusion battery was used to detect smaller particles in the unattached fraction area. The presented method can further refine the knowledge of the activity size distribution of radon decay products in different types of workplace atmospheres. Workplaces with higher radon concentrations differ significantly in the size distribution of aerosol particles, radon activity concentration, and equilibrium equivalent activity concentration.

Influence of particle lithology, size and angularity on rates and products of bedload wear: An experimental study

AbstractPhysical wear during bedload transport influences downstream changes in the size distributions and shapes of riverbed sediment, which in turn affect myriad fluvial processes ranging from incision into bedrock to provision of aquatic habitat. Here we use laboratory tumbling experiments to address several remaining knowledge gaps, including the roles of lithologic susceptibility to fragmentation, particle size distributions and particle angularity in controlling wear rates and the size distribution of wear products. To focus on the dynamics of particle wear in headwater channels, we used initially angular sediment and ran the experiments until 10% of the initial bedload particle mass had been lost to fine‐grained wear products. We measured individual particle mass and diameter by hand and used photo analysis to quantify particle shape and angularity. We find strikingly different wear patterns between limestone and welded tuff. Although wear rates in the tuff were an order of magnitude slower than the limestone, tuff wear was primarily by fragmentation while limestone wear was dominantly by attrition. Fragmentation of the tuff resulted in a widening of the bedload size distribution, a lack of consistent particle rounding and a fine‐wear product dominated by sand. In contrast, limestone particles rounded substantially and produced silt‐sized wear products. Differences in wear product size and susceptibility to fragmentation may reflect contrasts in the size distribution of mineral crystals in each lithology. Wear rates in both rock types declined substantially with increasing cumulative mass loss, due to rounding in the limestone and reduced fragmentation in the tuff. These results suggest that applications of the conventional exponential model to predict mass loss with travel distance need to account for lithologic influence on susceptibility to fragmentation and the influence of rounding on particle wear rates.

Demonstration of a novel jaw crusher design at a lab scale

ABSTRACT A novel jaw crusher was designed, constructed and tested at a lab scale. Differences from a conventional jaw crusher include a swing plate that is supported at the outlet, rather than the inlet, wear plates with a corrugation pattern that are designed to break the ore in bending rather than compression, and a trapezoidal wear plate shape to allow for swelling of broken ore. The crusher was tested using an ore sample that was mainly composed of feldspar. The performance of the crusher was evaluated by measuring changes in the size distribution of the ore and the corresponding electrical energy consumed, as a function of ore feed rate. The results indicated that the crusher product size distribution was narrower than that of the feed and independent of ore feed rate, with relatively little generation of fines, demonstrating that the crusher performed as designed in terms of ore breakage mechanism. Though calculated breakage efficiencies suggest that the crusher may be more energy efficient than a conventional jaw crusher, the use of an undersized crusher motor and possible deficiencies in the design of the transmission mechanism, prevent any concrete conclusions from being drawn.

Multi-Product Exporters: Verifying Stylized Facts

Abstract In this paper, we propose a statistical model to characterize the null hypothesis of the random product size distribution for multi-product exporters. It serves as a benchmark to test the empirical facts and model predictions. We ask which stylized facts that characterize multi-product exporters and motivate such theories as core competencies, productivity being a driver of both scope and scale, and economies of scope among others, are spurious, and which are informative. The benchmark model also provides alternative moments to test the validity of these theories.

Predictive modeling of crushing power in cone crushers with the discrete element method

In the mineral processing industry, crushers are relevant machines used for the comminution of ore. One method that has been used to model mining equipment is the discrete element method (DEM), which has proven to be an excellent tool for predicting the behavior of mineral processing machines. This paper presents a DEM model of a laboratory cone crusher with two versions: full and simplified. The simplified version — developed for simulation using fewer computer resources — is compared with the full model to analyze its usefulness. Complete and rigorous parameter calibration was performed, and the results obtained in both models were validated with experimental testing of crushing power, mass flow rate, and product size distribution; errors of less than 15% were obtained in all tests. In addition, a detailed analysis of the loads on the crusher mantle was performed using a polar coordinate representation of the crusher mantle.

Regulation of tea polyphenols in gluten-glucose Maillard reaction: Evaluation and analysis

Maillard reaction plays an important role in the flavour and color of some food. However, the excessive occurrence of Maillard reaction may affect the quality and safety of food. In this study, a simulated Maillard system composed of gluten and glucose was established to evaluate and analyze the regulatory role of tea polyphenols (TP) in it. The addition of tea polyphenols alleviated excessive browning of the Maillard reaction and significantly inhibited the accumulation of fructosamine and late glycosylation end products in the system. Based on the analysis of laser particle sizer and atomic force microscope, the large particle size distribution and aggregation structure of the Maillard reaction products in the tea polyphenol group disappeared. Further experiments showed that with the addition of tea polyphenols, the free radicals content in the system decreased, while the amount of reaction substrates increased. It was also shown that tea polyphenols effectively inhibited the isomerism of glucose to fructose and affected the content of free sulfhydryl and free amino groups in the system. The results indicated that tea polyphenols can regulate the Maillard reaction between gluten and glucose, which gives it the potential for application in the field of bakery and thermally processed foods.

The influence of branched polyethyleneimine concentration on the spectroscopic and morphology of BPEI/AuNPs for photocatalytic reduction of 4-nitrophenol

In this work, gold nanoparticles (AuNPs) were synthesized and stabilized by branched polyethyleneimine (BPEI) due to their amine groups as a low-cost alternative method. The concentration of BPEI as a critical factor can be used to optimize stable AuNPs with varying sizes. To evaluate BPEI concentrations on surface plasmonic resonance (SPR), size distribution, chemical coordination, and photocatalytic activity of BPEI-AuNPs products, UV–visible, transmission electron microscope, and Fourier transform infrared spectroscopy were used. The SPR bands appeared at 524, 520, and 517 nm as the BPEI concentration increased (10–30 µL), and the band remained stable as BPEI increased. TEM images show a wide range of sizes (polydisperse) for BPEI/AuNPs were formed. According to TEM images, gold nanoparticle sizes were calculated at (18, 12, and 5 nm) for BPEI concentrations 10, 20, and 30 µL. Fourier transform infrared spectroscopy (FTIR) revealed that amine groups from BPEI play an important role in stabilizing AuNPs. For accessing the photocatalytic activity of BPEI-AuNPs, the reduction of 4-nitrophenol (4-NP) by borohydride is a widely used model reaction. As the AuNPs sizes decreased from 18 to 5 nm, the reduction rate was accelerated and the reaction time of 4-NP to 4-AP conversion decreased from 270 to 150 s.

Experimental investigation on the preparation of macroscopic 0–1 mm powdered coal by a vertical spindle mill

The vertical spindle mill (VSM) is the key equipment to realize the preparation of 0–1 mm fuel used in powdered-coal-fired circulating fluidized bed combustion technology (PC-CFB). In this paper, a pilot-scale VSM test system was set up to explore the feasibility and operating performance of coarse-grained pulverized coal preparation. The effects of loading force, table revolution rate, and ventilation rate on the product size distribution, as well as the energy consumption of the grinding process were emphatically discussed. The results show that the product size of VSM increases with the decrease of loading force and the increase of ventilation rate, but too small a loading force will affect the normal output of VSM. Additionally, the product size of VSM decreases firstly and then increases with the increase of table revolution rate. Further, the energy consumption of the powdered coal preparation process was quantitatively described, and a semi-empirical model of comminution energy based on the powdered coal particle size distribution was proposed and verified by the measured values with an average accuracy of ±30 %. This model can estimate the power consumption of the mill, which can be used as an input parameter of the heat balance calculation model for the PC-CFB pulverizing system.

Auto-combustion synthesis and characterization of La2CrMnO6/g-C3N4 nanocomposites in the presence trimesic acid as organic fuel with enhanced photocatalytic activity towards removal of toxic contaminates

Constructing semiconductor materials based on layered graphitic carbon nitride (g-C3N4) and metal oxides can help in extending the lifetime of charge carriers and aid in resolving the low number of active sites on their surface for light-driven processes. Herein, we initially designed La2CrMnO6 nanostructures through trimesic acid-assisted auto-combustion route and subsequently, La2CrMnO6/g-C3N4 nanocomposites were prepared by ultrasonic-assisted co-precipitation method with improved UV-catalytic performance. The shape, size distribution and various properties of nano-sized products were measured via diverse description systems of microscopic and spectroscopic. The photocatalytic performances of the La2CrMnO6 nanoparticles and La2CrMnO6/g-C3N4 nanocomposites were compared by degradation of artificial dyes under the UV-light region. Besides, the impacts of dye type, diverse weight percentages of g-C3N4:La2CrMnO6 in composite, scavenger kind and dye solution concentration were studied on modifying ability of nano-catalyst utility. The outcomes manifested La2CrMnO6/g-C3N4 (80:20) nanocomposites have the greatest efficiency, where the highest MO decomposition of 80.98 % was achieved at 10 ppm within 90 min of irradiation. Moreover, the feasible mechanism of MO elimination by UV catalytic purpose was considered.

Tracking Prenucleation Molecular Clustering of Salicylamide in Organic Solvents.

Crystal nucleation shapes the structure and product size distribution of solid-state pharmaceuticals and is seeded by early-stage molecular self-assemblies formed in host solution. Here, molecular clustering of salicylamide in ethyl acetate, methanol, and acetonitrile was investigated using photon correlation spectroscopy. Cluster size steadily increased over 3 days and with concentration across the range from undersaturated to supersaturated solutions. Solute concentration normalized by solubility provided more sensitive characterization of molecular-level conditions than concentration alone. In saturated solution, cluster size is independent of solvent, while at equal supersaturation, solvent-dependent cluster size increases as methanol < acetonitrile < ethyl acetate, commensurate with increasing nucleation propensity. In ethyl acetate, with largest prenucleation clusters, the driving force required for nucleation is lowest, compared to methanol with smallest clusters and highest driving force. To understand solvent-solute effects, we performed IR spectroscopy supported by molecular simulations. We observe solute-solvent interaction weakening in the same order: methanol < acetonitrile < ethyl acetate, quantifying the weaker solvent-solute interactions that permit the formation of larger prenucleation clusters. Our results support the hypothesis that nucleation is easier in weaker solvents because weak solute-solvent interactions favor growth of large clusters, as opposed to relying solely on ease of desolvation.

SIZE DISTRIBUTION OF JAW CRUSHER CRUSHING PRODUCTS FOR ROUNDED MATERIAL

Abstract — Crushing is one of stage material size reduction in mineral processing. Jaw Crusher is one of the equipment that used to reduction size material and it’s generally used in primary crushing. Feed of crushing is come from mined material (Run of Mine-ROM) that have various shapes like very rounded, rounded, angular etc. Rounded material is one of them. The aim of this research is to calculate the size distribution and the pattern of size distribution product of crushing for rounded material. The equipment of crushing in this research was used Jaw Crusher in Mineral Processing Laboratory, Institut Teknologi Nasional Yogyakarta which 30 samples material. The same pattern of size distribution was obtained from the +4#, -4#+10#, -10#+20#, -20#+40#, -40#+60#, -60#+100#, -100#+200# dan -200# product size distribution. The biggest amount of size distribution was obtained in 4#. Limiting Reduction Ratio (LRR) were distributed in range 4-6. Losses percentage (% losses) of material crushing were less than 10%. Keywords: Crushing, limiting reduction ratio, losses, mineral processing, primary

Comparative Study of the Rosin-Rammler and Gates-Gaudin-Schuhmann Particle Size Distribution Models for Microwave-Assisted Crushing Analysis

Microwaves selectively heat dielectric minerals within the ore particles during a relatively brief exposure period, inducing thermal stresses that generate cracks, thereby diminishing the structural integrity of the ore particles. The immediate effect of employing this technique is an alteration in the particle size distribution (PSD) of the comminution product. In this research, two types of diamond-bearing kimberlite ore underwent microwave irradiation before the crushing process. The microwave experimentation was carried out utilizing a multi-variable power system with a maximum capacity of 15 kW, within a single-mode cavity structure. The exposure time was adjustable to vary the input microwave energy, which ranged from 6 kJ to 270 kJ. Three distinct narrow feed size classes were examined: -31.5 +16 mm, -16 +6.7 mm, and -31.5 +6.7 mm. Each sample weighed five hundred grams. Both the microwave-treated samples and the untreated samples (as-received) were subjected to crushing using a single-roll crusher. The PSD of the crushed product was determined through a standard sieving test and subsequently analyzed using empirical PSD models. These models are advantageous for enhancing the accuracy of PSD analysis by linearizing datasets that often exhibit skewness towards the distribution's tail end. Two widely recognized empirical PSD models, the Rosin-Rammler (RR) and Gates-Gaudin-Schuhmann (GGS) models, were employed to assess how microwave pre-treatment influences the PSD of the crushed product. Various comparative parameters derived from these models, such as the P50, distribution uniformity (DP), and critical fine sizes, were evaluated for both untreated crushed samples and the samples treated with microwaves. The findings indicated that crushed products treated with microwaves generally displayed improved alignment with both PSD models in comparison to the untreated samples. Notably, the GGS model exhibited marginally higher overall r-squared values compared to the RR model. Moreover, the microwave-treated samples showcased a slightly coarser and more uniform PSD when contrasted with the untreated counterparts. Among the various microwave energy inputs tested, the lowest input at the highest power level yielded the most substantial increments in P50 and DP. Simultaneously, it led to the most significant reduction in fractions corresponding to critical fine sizes.

Scale-Up Investigation of a Pilot and Industrial Scale Semi-Autogenous Mill Using a Particle Scale Model

A particle scale model based on a full two-way coupling of the Discrete Element Method (DEM) and Smoothed Particle Hydrodynamics (SPHs) methods is applied to SAG mills. Motion and collisions of resolved coarser particles within an SAG mill are performed by the DEM component. Fine particles in the feed combine with the water to form a slurry, which is represented by the SPH component of the model. Slurry rheology is controlled by solid loading and fine particle size distribution for each volume of slurry. Transport, dispersion, and grinding of the slurry phase particle size distribution are predicted by solving additional coupled advection–diffusion equations in the SPH component of the model. Grinding of the finer particles in the slurry due to collisions and shear of the coarser particles (rocks and grinding media) is achieved via the inclusion of population balance terms in these equations for each SPH particle. This allows prediction of the transport of both coarser and finer material within the grinding and pulp chambers of an SAG mill, including the discharge performance of the mill. This particle-scale model is used to investigate the relative performance (throughput, product size distribution, resident particle size distribution, net power draw, wear) for an SAG mill at a pilot scale and a 36 ft industrial scale. The 36′ SAG mill considered is a geometrically scaled-up version of the 1.8 m Hardinge pilot scale mill but with a longer belly length, reflecting current SAG mill design preferences. The belly lifters are scaled to a lesser degree with a larger number of lifters used (but still many fewer liners than would typically be used in a large SAG mill based on conventional liner selection rules). The model shows that despite reasonable qualitative similarities, many aspects of the charge structure, slurry transport, coarse particle and slurry discharge through the grates, and the collision energy spectra vary in important ways. This demonstrates that a near purely geometric scale-up of an SAG mill is not sufficient to produce a comparable performance at the two physical mill scales.

Production of High-Porosity Biochar from Rice Husk by the Microwave Pyrolysis Process

This study focused on the highly efficient pyrolysis of rice husk (RH) for producing high-porosity biochar at above 450 °C under various microwave output powers (300–1000 W) and residence times (5–15 min). The findings showed that the maximal calorific value (i.e., 19.89 MJ/kg) can be obtained at the mildest microwave conditions of 300 W when holding for 5 min, giving a moderate enhancement factor (117.4%, or the ratio of 19.89 MJ/kg to 16.94 MJ/kg). However, the physical properties (i.e., surface area, pore volume, and pore size distribution) of the RH-based biochar products significantly increased as the microwave output power increased from 300 to 1000 W, but they declined at longer residence times of 5 min to 15 min when applying a microwave output power of 1000 W. In this work, it was concluded that the optimal microwave pyrolysis conditions for producing high-porosity biochar should be operated at 1000 W, holding for 5 min. The maximal pore properties (i.e., BET surface area of 172.04 m2/g and total pore volume of 0.1229 cm3/g) can be achieved in the resulting biochar products with both the microporous and the mesoporous features. On the other hand, the chemical characteristics of the RH-based biochar products were analyzed by using Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDS), displaying some functional complexes containing carbon–oxygen (C–O), carbon–hydrogen (C–H), and silicon–oxygen (Si–O) bonds on the surface of the RH-based biochar.

Crushing characteristics and performance evaluation of iron ore in a cone crusher: A numerical study

In this study, the DEM (Discrete element method) bonded particle model is constructed to simulate the crushing process of iron ore based on the Apollonian sphere packing (ASP) method in a cone crusher. The effects of operation parameters (eccentric speed (ω), closed side setting (lcss) and eccentric angle (α)) on the macroscopic characteristics (throughput, specific energy, crushing rate, product size distribution) and microscopic characteristics (mechanical behaviors between sub-particles and between meta-particles) are systematically investigated, and their quantitative correlations are established. Meanwhile, the corresponding mechanisms have been identified by analyzing the circulation time. The results show that with alterations in operation parameters, the variation trend between production size distribution and crushing rate is consistent, while opposite trend between throughput and crushing rate is formed. The crushing rate is higher and the mantle wear is more severe when the normal/tangential forces exerted on particles are larger. The effects of the eccentric speed on the residence time of particles in the crushing chamber can be indicated by its influence on the number of circulations, while the effects of the closed side setting and eccentric angle can be reflected by changing the volume of the crushing chamber. The increase of particle residence time is beneficial for improving the crushing rate, while it simultaneously reduces the throughput.

Research on Hydrocyclone Separation of Palygorskite Clay

The separation methods of palygorskite can be divided into dry separation and wet separation. For wet separation, which is more efficient, the centrifuge is the commonly used method but is characterized as having a high cost. It remains a challenge to separate ultra-fine palygorskite with an economical method. This work tried to separate palygorskite using a hydrocyclone with two separation stages. Orthogonal experiments are designed to investigate the influence of feed concentration, feeding pressure, and underflow port diameter on separation performance. The element content, mineral composition, and particle size distribution of the separation products are analyzed, respectively, by XRD, XRF, and laser particle sizers. The apparent viscosity of palygorskite pulp is characterized by a rotational rheometer. The purity of the feed and palygorskite concentrate is measured using an internal standard method. The results show that the purity of palygorskite increased from 45.1% to 64.2%, with a recovery of 95.9%.

Effects of Al content and particle size on the combustion characteristic of hydrogen peroxide gel and micron-aluminum mixtures

As a novel green and high-performance propellants, H2O2/H2O/Al propellants have the potential to solve the pollution problem faced by composite solid propellants while maintaining high performance. However, the drawback that it cannot be ignited at a low oxidizer-to-fuel weight ratio (O/F) and a low pressure hinders its further development. Fortunately, this ignition defect was addressed by the mixture of hydrogen peroxide gel and micron-Al in our recent work. In this paper, the effects of Al content and particle size on the combustion characteristic of burning surface propagation and combustion products of the mixture were investigated. Combustion experiments were conducted in a windowed pressure vessel, using mixtures with three mixing ratios (fuel-lean, stoichiometric, and fuel-rich) and Al particle diameters between 1 and 12 μm. The burning surface propagation was captured by a high-speed camera. The particle size distribution, component, and morphology of combustion products were characterized by laser particle size analyzer, X-ray powder diffraction, and scanning electron microscopy, respectively. And it is the first time that the combustion properties of H2O2/H2O/Al propellants (including H2O/Al propellants) are studied from the prospective of particle size distribution of combustion products. Results showed that with the decrease of Al content and the increase of particle diameter, the combustion intensity of the mixture decreased, resulting in the agglomeration of melted Al droplets on the burning surface. When the Al content was decreased to O/F = 1.7, Al particles in the mixture were no longer further oxidized in the process of combustion. When the Al particle diameter was increased to 7–10 μm, burning rates of the mixture at O/F = 1.7–1.1 tended to be stable. The combustion of mixtures containing 3–7 μm was kinetically controlled. From the prospective of variable burning rate and efficient combustion, the appropriate Al content in the mixture was O/F = 1.7–1.1, and the Al particle diameter should be kept within 1–7 μm.

A promising method for the liberation and separation of solar cells from damaged crystalline silicon photovoltaic modules

Reasonable and efficient recycling of waste crystalline silicon (c-Si) photovoltaic (PV) modules benefits environmental protection and resource conservation. The liberation and separation of solar cells in modules is the key to achieving effective recycling. The recovery of intact waste modules has been studied by some scholars, but few have specifically examined damaged modules. This study focused on modules that have been broken during transportation, installation, use, or disassembly. Two liberation methods, mechanical crushing and pyrolysis were compared from the perspectives of particle size distribution and morphological characteristics of products. In addition, for separating glass particles and solar cells of coarse fraction, an environmentally-friendly technology of gas-solid fluidized bed was introduced based on their shape and density difference. The effects of airflow velocity and fluidizing time on separation efficiency were investigated for different size fractions. Results showed that pyrolysis was a more suitable liberationliberation method for damaged modules. Higher liberation efficiency could be obtained by pyrolysis, and over-crushing of glass particles and solar cells could be avoided. The optimum pyrolysis conditions were found to be at 500 °C with a holding time of 30 min. The recovery and concentration of solar cells in the >4 mm size fraction were 91.09% and 84.4%, respectively, under the following conditions: 85 m3/h airflow velocity; 90s fluidizing time. For the 2–4 mm size fraction, the recovery and concentration were 82.29% and 80.52% under airflow velocity of 75 m3/h, fluidizing time of 90s. This research presents an alternative process for recovering damaged c-Si PV modules.

Mitigating drying shrinkage and enhancing mechanical strength of fly ash-based geopolymer paste with functionalized MWCNTs grafted with silane coupling agent

In this study, the functionalized MWCNTs grafted with silane coupling agent are obtained by means of successive chemical modification methods. The structure and dispersity of the functionalized MWCNTs are characterized using the FT-IR, XPS and HR-TEM, respectively. Then the reaction kinetics, mineralogical phases, morphology and elemental components of modified geopolymer incorporated with the functionalized MWCNTs are evaluated by means of the XRD, TAM, FT-IR and SEM-EDS analysis. In addition, the influences of functionalized MWCNTs on the mechanical strength and drying shrinkage behaviors are investigated. The MIP and 29Si NMR are employed to investigate the pore size distribution and microstructural rearrangement of gel products. The results show that the functionalized MWCNTs can be dispersed uniformly in aqueous solution without any dispersant. Importantly, the modified geopolymer incorporated with 0.2% functionalized MWCNTs-KH550 exhibits a lower drying shrinkage(0.098%) and higher mechanical strength compared with that of all geopolymer pastes. The hydrophobic modification of functionalized MWCNTs reduces significantly the mass loss of the geopolymer. The MIP results indicate that a critical pore size(ds)computed from both the pore size distributions and water loss is related with drying shrinkage, and the drying shrinkage of geopolymer pastes decreases with the increment of the ds value. A strong interaction between adjacent C(N)-A-S-H particles occurs in microstructure rearrangement period by means of the silicate polymerization and micropore closure. Moreover, the new dual interaction mechanism decreasing drying shrinkage and increasing mechanical strength of geopolymer pastes are proposed.