Volume Shrinkage Research Articles

Two Types of Negative Thermal Expansion Observed in PbCr1–xTixO3

Two negative thermal expansions (NTEs) with different mechanisms were observed in solid solutions of perovskite-type oxides PbCrO3 and PbTiO3. PbCr1–xTixO3 was found to adopt a cubic structure the same as that of PbCrO3 for x ≤ 0.6 and a PbTiO3-type tetragonal structure for x ≥ 0.7. The NTE observed at x ≤ 0.6 was accompanied by a cubic-to-cubic phase transition originating from the rearrangement of Pb2+/Pb4+ in a complex local structure called a charge glass. The volume shrinkage of −2.5% observed in PbCrO3 is sufficiently large despite the absence of intermetallic charge transfer, which is the origin of pressure-induced cubic-to-cubic phase transition and 9.8% volume collapse. The NTE in the tetragonal phase was caused by the ferroelectric-to-paraelectric phase transition, the same as in PbTiO3. We succeeded in significantly lowering the working temperature of PbTiO3 as an NTE material by Cr substitution while retaining a large volume shrinkage of 0.6%.

Phase-Transformation Nanoparticles Synchronously Boosting Mechanical and Electromagnetic Performance of SiBCN Ceramics

Precursor-derived silicoboron carbonitride ceramic (PDC-SiBCN) has attracted significant attention as an advanced electromagnetic (EM) wave-absorbing material. However, the inherent porous and brittle characteristics limit its application as a structural load component in an EM interference environment. In this study, phase-transformation HfO2 nanoparticles were incorporated into PDC-SiBCN to reduce volume shrinkage, improve bonding interactions, and control structural defects, simultaneously boosting the plastic deformation and EM performance of brittle ceramics. The obtained HfO2/SiBCN ceramic showed enhanced flexural strength of up to 430.1% compared with that of the pure SiBCN ceramic. Furthermore, the HfO2/SiBCN ceramic also demonstrated excellent high-temperature EM absorption. The minimum reflection coefficient (RCmin) could reach -45.26 dB, and the effective absorption bandwidth (EAB) covered 2.80 GHz of the X band at 2.28 mm thickness at room temperature. Furthermore, the RCmin can still reach -44.83 dB, and the EAB can cover 2.4 GHz at 1.58 mm even at 1073 K. This work shows that phase-transformation nanoparticles could simultaneously improve the deformation ability and EM wave absorption properties of SiBCN ceramics. The results could guide the design and preparation of PDCs with strong carrying capacity and excellent EM absorption, even in harsh environments.

Three-dimensional nanoporous Ag fabricated by a reduction-induced approach for sensitive surface-enhanced Raman scattering

Nanoporous metals with high specific surface area, excellent conductivity, and unique surface structure have attracted attention in a variety of applications such as catalysis, energy storage, and sensing. However, there is a significant challenge for the fabrication of uniform nanoporous architectures in metals through a simple and cost-effective process. In this study, we report a facile approach to create monolithic nanoporous Ag (MNPA) from the direct reduction of insoluble Ag2O precursor in an aqueous solution, fundamentally avoiding the introduction of secondary components and complex preparation of precursors. The formation of porous structures is attributed not only to the volume shrinkage but also to the spontaneous reconstruction of reserved Ag atoms during the reduction process. Furthermore, for a typical application, the optimized MNPA with a small grain size (∼113 nm) is used as a surface-enhanced Raman scattering (SERS) substrate, which exhibits ultrahigh SERS sensitivity with an enhancement factor of ∼109.

Optimization of injection molding process parameters for the lining of IV hydrogen storage cylinder

The hydrogen storage cylinder lining was taken as the research object. The injection model of the cylinder liner was developed employing 3D software, a two-cavity injection molding system was built, and Moldflow was utilized for analysis to determine the best combination of injection molding process parameters. The effects of injection process parameters (melt temperature, mold temperature, holding pressure, holding time and cooling time) on the evaluation index were analyzed by orthogonal experiment L16(45). The prediction data of IV hydrogen storage cylinder lining under different parameters were obtained by the range analysis method. The multi-objective optimization problem of injection molding process was transformed into a single-objective optimization problem by using the grey correlation analysis method. The optimal parameters such as melt temperature 270 °C, mold temperature 80 °C, packing pressure 55 MPa, packing time 20 s and cooling time 13 s were obtained. Taguchi method was adopted to obtain SNR (signal-to-noise ratio), while range and variance methods were used for analysis. The results showed that warpage was 0.4892 mm, the volume shrinkage was 12.31%, the residual stress in the first direction was 98.13 MPa, and the residual stress in the second direction was 108.1 MPa. The comprehensive index was simultaneously most impacted by the melt temperature.

Graphene Aerogel‐Supported Phase‐Change Material for Pyroelectric Energy Harvesting: Structural Modification and Form Stability Analysis

3D porous graphene aerogel (GA) has a capability to infiltrate plenty of phase‐change materials (PCM) into the internal pore. Since carbon‐based materials can offer excellent solar light absorption and conversion of thermal energy, they are widely used as container‐like supporting materials. In general, the GA shows a volume shrinkage problem due to the capillary force during the infiltration process, thus causing a loss in pore volume, that is, PCM weight loss. The PCM amount is proportional to both the absorbed and released thermal energies. Herein, cysteamine is introduced to bind GA. The PCM composite can reduce the volume shrinkage and have an excellent form stability even under the external force. Two kinds of PCMs are connected to a pyroelectric electrode to generate electrical energy. In addition, finite‐element method estimates the temperature profile and electrical peaks to confirm experimental results.

Development of a Novel Tape-Casting Multi-Slurry 3D Printing Technology to Fabricate the Ceramic/Metal Part.

Printing ceramic/metal parts increases the number of applications in additive manufacturing technology, but printing different materials on the same object with different mechanical properties will increase the difficulty of printing. Multi-material additive manufacturing technology is a solution. This study develops a novel tape-casting 3D printing technology that uses bottom-up photopolymerization to fabricate the green body for low-temperature co-fired ceramics (LTCC) that consist of ceramic and copper. The composition of ceramic and copper slurries is optimized to allow printing without delamination and sintering without cracks. Unlike traditional tape-casting processing, the proposed method deposits two slurries on demand on a transparent film, scrapes it flat, then photopolymerization is induced using a liquid crystal displayer to project the layer pattern beneath the film. The experimental results show that both slurries have good bonding strength, with a weight ratio of powder to resin of 70:30, and print a U-shaped copper volume as a circuit within the LTCC green body. A three-stage sintering parameter is derived using thermogravimetric analysis to ensure good mechanical properties for the sintered part. The SEM images show that the ceramic/copper interface of the LTCC sintered part is well-bonded. The average hardness and flexural strength of the sintered ceramic are 537.1 HV and 126.61 MPa, respectively. Volume shrinkage for the LTCC slurry is 67.97%, which is comparable to the value for a copper slurry of 68.85%. The electrical resistance of the printed copper circuit is 0.175 Ω, which is slightly greater than the theoretical value, hence it has good electrical conductivity. The proposed tape-casting 3D printer is used to print an LTCC benchmark. The sintered benchmark part is validated for the application in the LTCC application.

Synthesis of Nanocrystalline Yttrium Oxide and Evolution of Morphology and Microstructure during Thermal Decomposition of Y2(C2O4)3·10H2O

A study of the morphology and evolution of the microstructure during thermal decomposition of Y2(C2O4)3·10H2O was conducted, and the stages and factors having the greatest impact on particle size and specific surface area were identified. The effect of the yttrium oxalate hexahydrate phases on the course of decomposition was also investigated. The evolution of the morphology and microstructure of decomposition products was explained from the analysis of volume shrinkage at various stages of the reaction. The formation of oxycarbonate is accompanied by the largest shrinkage during the reaction. At this stage, there is a significant increase in the specific surface area to 60–90 m2/g. Conversely, the morphology and microstructure of the particles during the transformation of oxycarbonate into yttrium oxide change insignificantly. Yttrium oxide powders obtained from the monoclinic and triclinic hexahydrate phases have the same specific surface area, but different morphology and bulk density due to pseudomorph formation. The carbon formed during thermolysis was shown to affect the specific surface area of the decomposition product. Two methods for producing yttrium oxide with high specific surface area have been proposed, and nanocrystalline yttrium oxide with a specific surface area of 65 m2/g was obtained.

Crystallites Dimensions and Electrical Conductivity of Solid Carbon Pellets (SCPs) from Date Palm Leaves (Phoenix dactylifera L.)

Solid carbon pellets (SCPs) were prepared from self-adhesive properties of date palm leaves (Phoenix dactylifera L.), primary pre-carbonized at low temperature, milled to fine grain, powdered, and pelletized as a grain pellet by applying of (5-21) metric tons of compression load, to carbonization at 1000 ºC. The SCPs produced were analyzed in terms of the volume shrinkage, carbon yield, crystallites dimensions and electrical conductivity of the solid carbon pellets as a function of compression load. The values of the electrical conductivity were further analyzed in terms of percolation theory to estimate the critical density of the SCPs produced. The results show that the volume shrinkage and carbon yield after carbonization were in a range of 54.0-64.8% and 26.98-32.4%, respectively, indicating that the body is physically shrinking to maintain its structural integrity. X-ray diffraction intensity shows that the structures of the SCPs are non-graphitic, and their crystallite dimensions are improved by increasing the compressive load. The d002, Lc and La data were found to obey the linear relation of d002 versus 1/ Lc and 1/ La, as Lc and La approach infinity. The electrical conductivity was varied with the compression load and 19 metric tons is a higher value than the others. The critical density of the SCP obtained from the percolation theory was 0.025 g/cm3.

Surrounding rock stability of horizontal cavern reconstructed for gas storage

Rock salt is recognized in the world to be an ideal medium for storing oil and natural gas. There are a lot of dissolved caverns formed by salt extraction in China which are mainly divided into horizontal caverns and pear-shaped caverns, among which the number of old horizontal caverns is the largest. However, the existing old horizontal caverns cannot be directly used to store oil and natural gas and need to be reconstructed. The method of drilling new wells outside the caverns to reconstruct the horizontal old caverns was introduced first; Then the possible influence factors of surrounding rock stability in horizontal caverns reconstruction were discussed by using mechanics theories; Finally, the influence of drilling new wells outside the caverns on the stability of surrounding rock of horizontal old caverns and the salt roof was obtained by numerical simulation, including the volume shrinkage rate of the reconstructed horizontal caverns, the plastic zone and displacement distribution of surrounding rock and salt layer roof. The results of theoretical analysis and numerical simulation show that the volume of the new drilling caverns, the distance between the new drilling cavern and the old cavern, the internal pressure during gas storage, and the operation time of storage are the main factors affecting the stability of the surrounding rock of the horizontal cavern and its salt layer roof, which indirectly determines whether the horizontal old cavern can be successfully reconstructed into gas storage.

Discovery of robust superconductivity against volume shrinkage

The superconducting transition temperature (<i>T</i><sub>c</sub>) of superconductor is related intimately to multiple degree of freedom of charge, spin, orbital and lattice. Many studies have indicated that pressure is an effective way to tune <i>T</i><sub>c</sub> though changing crystal structure and electronic structure. Here, we report a new progress made in the high-pressure studies – discovery of a new type of superconductors whose <i>T</i><sub>c</sub> is robust against large volume shrinkage under extremely high pressure, named RSAVS (robust superconductivity against volume shrinkage) superconductor. Such RSAVS behavior was observed initially in the high entropy alloys of (TaNb)<sub>0.67</sub>(HfZrTi)<sub>0.33</sub> and (ScZrNbTa)<sub>0.6</sub>(RhPd)<sub>0.4</sub>, then in the widely-used NbTi alloy, Nb and Ta elements. Analysis shows that this type of superconductor possesses a body-centered cubic crystal structure and is composed of transition metal elements. The observed results not only present new research topics but also raise the question of what determines <i>T</i><sub>c</sub> of conventional or unconventional superconductors.

Preparation of high-temperature gels for enhanced oil recovery using methyl etherized melamine-formaldehyde resin

Polymer gels are the most commonly used materials in the petroleum industry for reservoir conformance control and resolving excessive water production problems. In this study, high-temperature gels were prepared with HPAM or AM/AMPS as the gel-forming agent, methyl etherified melamineformaldehyde resin (MEMFR) as the crosslinker, and nano-silica as the stabilizer, and their properties were evaluated. The results showed that HPAM-MEMFR gels were unstable at 110°C in a brine of 20665 mg/L. AM/AMPS-MEMFR gels are stable at 110°C, with gelation time ranging from 15 h to 92 h and storage modulus ranging from 3.6 Pa to 50 Pa. AM/AMPS-MEMFR gel has less than 10% dehydration after aging at 110°C for 90 days, almost no shrinkage in volume, and a significant increase in strength, making it suitable as a gel material for enhanced oil recovery.

Classification of Principal Wood Species in China Based on the Physiomechanical Properties

Many tree species are planted in China with variable properties and usage. Toward exploring the structure-properties relationships of wood and classifying the species more reasonably, the physiomechanical properties of the domestic wood species in China were analyzed statistically. According to the correlation analysis, the mechanical properties were closely related to the wood density. Except impact toughness and cleavage strength, the correlation coefficients between mechanical properties and densities were more than 0.8. However, shrinkage properties showed fewer correlations with densities, and the coefficient was no more than 0.7. Primary component analysis was proved to be feasible to explore the information of the physiomechanical properties. Two principal components (PC1 and PC2) could account for most of the information. PC1 and PC2 were designated as density-dominated and shrinkage-associated factors, respectively. The domestic wood species in China could be classified into 4 clusters based on their physiomechanical properties. According to the cluster results, reasonable grading was proposed for air-dried density, volume shrinkage, modulus of rupture, compression strength parallel to grain and hardness in cross section. The statistical results brought insights into analyzing the physiomechanical properties of domestic Chinese wood species, which was helpful for developing strategies of tree breeding and technologies of wood processing.

Experimental and numerical study on the shrinkage-deformation of carrot slices during hot air drying

In order to further understand the mechanism of material volume change in the drying process, numerical simulations (considering or neglecting shrinkage) of heat and mass transfer during convective drying of carrot slices under constant and controlled temperature and relative humidity were carried out. Simulated results were validated with experimental data. The results of the simulation show that the Quadratic model fitted well to the moisture ratio and the material temperature data trend with average relative errors of 5.9% and 8.1%, respectively. Additionally, the results of the simulation considering shrinkage show that the moisture and temperature distributions during drying are closer to the experimental data than the results of the simulation disregarding shrinkage. The material moisture content was significantly related to the shrinkage of dried tissue. Temperature and relative humidity significantly affected the volume shrinkage of carrot slices. The volume shrinkage increased with the rising of the constant temperature and the decline of relative humidity. This model can be used to provide more information on the dynamics of heat and mass transfer during drying and can also be adapted to other products and dryers devices. Keywords: carrot drying, numerical simulation, heat, and mass transfer, shrinkage DOI: 10.25165/j.ijabe.20231601.6736 Citation: Jiang D L, Li C C, Lin Z F, Wu Y T, Pei H J, Zielinska M, et al. Experimental and numerical study on the shrinkage-deformation of carrot slices during hot air drying. Int J Agric & Biol Eng, 2023; 16(1): 260–272.

A Comprehensive Method for the Optimization of Cement Slurry and to Avoid Air Channeling in High Temperature and High-Pressure Conditions

Air channeling in the annulus between the casing and the cement sheath and/or between the cement sheath and formation is the main factor affecting the safe operation of natural gas wells at high temperatures and pressures. Prevention of this problem requires, in general, excellent anti-channeling performances of the cement sheath. Three methods to predict such anti-channeling performances are proposed here, which use the weightless pressure of cement slurry, the permeability of cement stone and the volume expansion rate of cement sheath as input parameters. Guided by this approach, the anti-channeling performances of the cement slurry are evaluated by means of indoor experiments, and the cement slurry is optimized accordingly. The results show that the dangerous transition time of the cement slurry with optimized dosage of admixture is only 76 min, the permeability of cement stone is 0.005 md, the volume shrinkage at final setting is only 0.72%, and the anti-channeling performances are therefore maximized. The effective utilization of the optimized cement slurry in some representative wells (LD10–1-A1 and LD10–1-A2 in LD10–1 gas field) is also discussed.

Understanding ZIF particle chemical etching dynamics and morphology manipulation: in situ liquid phase electron microscopy and 3D electron tomography application.

In situ liquid phase transmission electron microscopy (TEM) and three-dimensional electron tomography are powerful tools for investigating the growth mechanism of MOFs and understanding the factors that influence their particle morphology. However, their combined application to the study of MOF etching dynamics is limited due to the challenges of the technique such as sample preparation, limited field of view, low electron density, and data analysis complexity. In this research, we present a study employing in situ liquid phase TEM to investigate the etching mechanism of colloidal zeolitic imidazolate framework (ZIF) nanoparticles. The etching process involves two distinct stages, resulting in the development of porous structures as well as partially and fully hollow morphologies. The etching process is induced by exposure to an acid solution, and both in situ and ex situ experiments demonstrate that the outer layer etches faster leading to overall volume shrinking (stage I) while the inner layer etches faster giving a hollow morphology (stage II), although both the outer layer and inner layer have been etched in the whole process. 3D electron tomography was used to quantify the properties of the hollow structures which show that the ZIF-67 crystal etching rate is larger than that of the ZIF-8 crystal at the same pH value. This study provides valuable insights into MOF particle morphology control and can lead to the development of novel MOF-based materials with tailored properties for various applications.

Revealing the effect of Nb or V doping on anode performance in Na2Ti3O7 for sodium-ion batteries: a first-principles study.

Sodium titanate Na2Ti3O7 (NTO) has superior electrochemical properties as an anode material in sodium-ion batteries (SIBs), and Nb or V doping is suggested to enhance the electrode performance. In this work, we carry out systematic first-principles calculations of the structural, electronic and electrochemical properties of NTO and Na2Ti2.75M0.25O7 (M = Nb, V), using supercells to reveal the effect of Nb or V NTO-doping on its anode performance. It is found that Nb doping gives rise to the expansion of cell volume but V doping induces the shrinkage of cell volume due to the larger and smaller ionic radius of the Nb and V ions, respectively, compared to that of the Ti ion. We perform structural optimization of the intermediate phases of Na2+xM3O7 with increasing Na content x from 0 to 2, revealing that the overall relative volume expansion rate is slightly increased by Nb and V doping but remains lower than 3%. Our calculations demonstrate that the electrode potential of NTO is slightly raised and the specific capacity is reduced, but the electronic and ionic conductivities are improved by Nb or V doping. With the revealed understanding and mechanisms, our work will contribute to the search for advanced electrode materials for SIBs.

Percutaneous high-dose-rate interstitial brachytherapy for non-resectable, chemo resistant malignant lesion of lung and liver.

To explore the feasibility and efficacy of interstitial brachytherapy application for nonresectable and chemo-resistant malignant liver and lung lesions. Percutaneous high-dose-rate interstitial brachytherapy (HDR ISBT) was applied in nine lesions of seven middle-aged patients with advanced carcinoma (five patients with liver lesion and two patients with lung lesion). All patients were surgically ineligible. All patients had already received systemic chemotherapy. Under computed tomography (CT) guidance (for lung lesion) or ultrasonography (USG) guidance (for liver lesion), a single stainless steel brachytherapy needle was inserted percutaneously in patients with lesion size ≤4 centimeter (cm) and multiple needles were inserted in patients of lesion size >4cm. A single dose of 15 Gy to 20 Gy with HDR ISBT was prescribed at the periphery of the lesion. The needles were removed just after treatment. Patients were kept under observation for 24 h after treatment. The median size of the lesion was 6.5 cm. In all the cases of liver lesion, more than 75% shrinkage of tumor volume in follow-up at 6 mo was observed. It was more than 50% for lung lesion. None of the patients had developed significant complications as on the median follow up period of 15 mo (ranges 3-27 mo). Percutaneous CT-guided high-dose-rate interstitial brachytherapy is a minimally invasive, safe, and feasible treatment option with minimal complication for inoperable, chemo resistant, advanced cancers with encouraging treatment outcomes.

Atomic-scale insight into the lattice volume plunge of LixCoO2 upon deep delithiation

The O ↔ O interlayer distance across Li layer and Co layer are responsible for the volume increase and decrease in LixCoO2, while the delithiation paths have an impact on the volume shrinkage points, corresponding to different capacity utilization.

Development of Energy-Efficient “Cold” Curing Method for Polypropylene Glycol Fumarate Using an Optimized Initiating System

The possibility of using the polymeric matrix obtained as a result of “cold” polymerization of polypropylene glycol fumarate (p-PGF) with methacrylic acid (MAA) as a polymeric base for obtaining new adhesives of domestic production was demonstrated. The starting reagent (p-PGF) was synthesized by condensation polymerization of fumaric acid with propylene glycol in the presence of a catalyst, which reduced the temperature and shortened the process time. A number of solutions of p-PGF in MAA of different mass compositions were obtained and their rheological properties were determined. Curing of the studied solutions was carried out by radical polymerization at room temperature in the presence of the “cold curing” initiating system. The optimum composition and amount of components of the “cold” curing initiating system consisting of an initiator (benzoyl peroxide) and a promoter (dimethylaniline) were established. Technological parameters of curing (temperature, lifetime and curing time, the value of volume shrinkage) were determined. The obtained compounds were identified by infrared spectroscopy. The surface morphology of the cured samples was studied by scanning electron microscopy. It was found that varying the composition of the initial polymermonomer mixture allows controlling the physicochemical properties.

Exploring the Mechanical Properties, Shrinkage and Compensation Mechanism of Cement Stabilized Macadam-Steel Slag from Multiple Perspectives

Steel slag is characterized by high strength, good wear resistance and micro-expansion. This study aims at exploring the potential of steel slag in cement stabilized aggregates, mainly including mechanical properties, shrinkage and compensation mechanisms. For this purpose, the compressive strength and compressive resilient modulus of cement stabilized aggregates with different steel slag contents (CSMS) were initially investigated. Subsequently, the effects of steel slag and cement on dry shrinkage, temperature shrinkage, and total shrinkage were analyzed through a series of shrinkage test designs. Additionally, in combination with X-ray diffraction (XRD) and Scanning electron microscope (SEM), the characteristic peaks and microscopic images of cement, steel slag and cement-steel slag at different hydration ages were analyzed to identify the chemical substances causing the expansion volume of steel slag and reveal the compensation mechanism of CSMS. The results show that the introduction of 20% steel slag improved the mechanical properties of CSMS by 16.7%, reduced dry shrinkage by 21%, increased temperature shrinkage by 5.8% and reduced its total shrinkage by 19.2%. Compared with the hydration reaction of cement alone, the composite hydration reaction of steel slag with cement does not produce new hydrates. Furthermore, it is noteworthy that the volume expansion of the f-CaO hydration reaction in steel slag can compensate for the volume shrinkage of cement-stabilized macadam. This research can provide a solid theoretical basis for the application and promotion of steel slag in cement-stabilized macadam and reduce the possibility of shrinkage cracking.