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The aim of this paper is to review the developments in the use of superabsorbent polymer (SAP) in cementitious materials. This review covers the classification, properties, and methods for testing SAP, along with its impact on concrete properties, and other noteworthy developments in SAP usage. Various methods can be used to test the water absorption by SAP. Among them, the tea bag method is considered a simple and time-saving test, while centrifuge and suction filtration methods are regarded as accurate because they remove inter-particle liquid. The water absorption by SAP is affected by factors such as SAP composition, method of preparation, physical characteristics, and properties of the fluid. Higher fluid temperature (e.g., 60 °C) leads to greater absorption and release distance, while higher pH levels (pH 13) result in lesser absorption. The optimal dosage of SAP varies between studies, generally ranging from 0.1% to 1.5%. Higher SAP content (0.3–8%) reduces workability and decreases slump. Results related to strength vary; some studies have reported increased strength due to SAP's maintenance of higher internal relative humidity, while others have observed decreased strength due to increased porosity caused by SAP. The inclusion of SAP typically leads to a strength recovery of about 10% over time due to the continuous hydration process. Curing methods also influence strength, with sealed curing showing greater strength. Additionally, an increase in SAP dosage (0.1–0.6%) reduces shrinkage. Furthermore, the paper discusses the challenges encountered while using and testing SAP, as well as the explanations provided by researchers. [ABSTRACT FROM AUTHOR]

AbstractThe objective of this study is to investigate the potential of combined pond fly ash (PFA) and flue gas desulfurization gypsum (FGDG) as a partial replacement for cement by mixing them with fine river sand for green mortar development. We studied the physical, mechanical, and microstructural properties of mortars by using techniques such as scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDXS) and X-ray diffraction (XRD) for chemical component identification of the hydrated phase. These experimental results show that mortar containing pond fly ash, FGDG, and cement concentrations of 5 wt%, 5 wt%, and 90 wt% yields the maximum compressive strength (8.9 MPa) and flexural strength (3.4 MPa) after 28 days. This mortar has 12.6% higher compressive strength and 48% lower shrinkage in comparison with control specimens. A reduction in shrinkage is attributed to the denser structure of the mortar, as the calcium silicate hydrate (C–S–H) gel is found to exist in the SEM image and also identified through XRD studies. It is also concluded that excessive ettringite formation causes expansion in the volume of mortar, voids formation, and results in the reduction of strength. The application of this mortar can be in the internal plaster, bricks, and masonry. [ABSTRACT FROM AUTHOR]

We propose a new shrinkage and variable selection method in linear regression, which is based on triple shrinkage on the regression coefficients. The new estimation method contains the ridge, lasso and elastic net as special cases. The term based on the shrunken estimator in the new method can provide estimates with a smaller length depending on the size of a new tuning parameter compared to the elastic net, maintaining the variable selection feature in the case of multicollinearity. The new estimator has the property of the grouping effect similar to that of the elastic net. The well-known coordinate descent algorithm is used to compute the coefficient path of the new estimator, efficiently. We conduct real data analysis and simulation studies to compare the new estimator with several methods including the lasso and elastic net. [ABSTRACT FROM AUTHOR]

The characteristics of shotcrete can lead to significant shrinkage deformation, presenting potential threats to tunnel structure safety. To research this concern, in this study the effects of three accelerators on the volume stability of cement paste, cement mortar and concrete were investigated. The correlation equations of the shrinkage deformation of cement paste, cement mortar and concrete were established, and the drying shrinkage prediction model of cement mortar with accelerator was constructed by combining the ACI 209 model and the GL2000 model. Findings from this study show that the liquid alkali accelerator AR had the greatest autogenous shrinkage and drying shrinkage, with the highest mass loss under drying conditions. The study demonstrated that there exists a good linear relationship between the shrinkage deformation of cement paste, cement mortar and concrete with accelerator. Finally, the proposed prediction model for drying shrinkage of cement mortar exhibits strong predictive capabilities. [ABSTRACT FROM AUTHOR]

Cracks in concrete structures are generally initiated due to the shrinkage i.e. the volume change characteristics of the concrete structures. In this experimental study, effects of the mix parameters related to alkaline liquid (AL) and recycled fine aggregate (RFA) on the shrinkage behaviour of environment-friendly mortar mixes produced with fly ash (FA)-based geopolymer binder and RFA were investigated and reported. To find out the effects of AL, concentration of liquid sodium hydroxide (LSH) was varied from 6M to 16M, ratio of liquid sodium silicate (LSS) to LSH in AL was varied from 1.0 to 2.5 and AL/FA ratio was considered as 0.4 and 0.6. Different fly ash-based geopolymer mortar mix were produced depending on above-said combinations of mix parameters along with the RFA content (by weight) of 10%, 20%, 30%, 40% and 50% in lieu of natural fine aggregate. Prismatic specimens (25 mm × 25 mm × 285 mm) were cast and cured at ambient air temperature to determine the shrinkage behaviour. Higher RFA content in mix, higher LSS/LSH ratio in AL and higher AL/FA ratio resulted in higher shrinkage value. But, lesser shrinkage value was noticed for those specimens of mortar mix with the consideration of higher concentration of LSH in AL with varying RFA content. [ABSTRACT FROM AUTHOR]

In this study, the ceramic cores were printed with heavy calcium carbonate (HCC, CaMg(CO 3) 2) powder as raw material and Al powder as additive by binder jetting (BJ). The ceramic cores were impregnated with nano-ZrO 2 dispersion solution and then sintered at high temperature to prepare the ceramic cores with low sintering shrinkage. The effects of different Al powder contents (20 wt%∼40 wt%) on the properties and sintering shrinkage of the ceramic cores were studied. It was found that with the increase of Al powder content (20 wt%∼40 wt%), the bending strength of the ceramic core gradually decreased from 35.82 MPa to 11.89 MPa, and the porosity continuously increased from 8.94 % to 46.4 %. The sintering shrinkage rate of the ceramic core also gradually decreased, and even slightly expanded. This is because the oxidation of the Al powder to Al 2 O 3 produced a large volume expansion, and the Al 2 O 3 reacted with the CaO and MgO generated by the decomposition of HCC to produce calcium hexaluminate (CA 6), calcium dialuminate (CA 2), MgAl 2 O 4 (MA) and other substances, and these reaction processes also produced a certain volume expansion. When the amount of the Al powder was 40 %, the dimensional change rates of X, Y and Z axis of the ceramic core were 2.48 %, 2.35 % and −0.6 %, respectively. Compared with the ceramic core without Al powder, the sintering shrinkage rate decreased by 91.2 %, and the dimensional accuracy of the ceramic core was improved significantly. By observing the microstructure of the ceramic cores, it is found that various substances inside the ceramic core formed a network distribution structure, which achieved a good toughening effect and ensured that the ceramic core had a good bending strength under large porosity. [ABSTRACT FROM AUTHOR]

Cracks induced by internal stresses compromise the structural integrity of ceramic laminates. Such stresses can be classified into thermal stress derived from thermal expansion mismatch and shrinkage stress derived from shrinkage mismatch. Analytical models have been proposed for the former, whereas only numerical predictions have been explored for the latter. In this study, an equation is constructed to predict the shrinkage stress by modifying an elastic solution proposed in previous studies. We fabricated laminates with three‐layer sandwiched structures using only alumina specimens with high and low densities to control the shrinkage and avoid thermal mismatch. Surface cracks were initiated when the shrinkage stress exceeded the flexural strength of the surface layer. Although the original strength of the surface layer was 308.8 MPa, the laminates' flexural strength was lower than that because of shrinkage constraint. Our results demonstrate that the shrinkage stress was successfully estimated analytically using a few material properties measured in an ordinary environment. This study will ensure the structural integrity of ceramic laminates in laminate designs. [ABSTRACT FROM AUTHOR]

We derive analytical expressions for the risk of an investor's expected utility under parameter uncertainty. In particular, our analysis focuses on characterizing the out-of-sample utility variance of three portfolios: the classic mean-variance portfolio, the minimum-variance portfolio, and a shrinkage portfolio that combines both. We then use our analytical expressions to study a robustness measure that balances out-of-sample utility mean and volatility. We show that neither the sample mean-variance portfolio nor the sample minimum-variance portfolio exhibits maximal robustness individually, and one needs to combine both to optimize portfolio robustness. Accordingly, we introduce a robust shrinkage portfolio that delivers an optimal tradeoff between out-of-sample utility mean and volatility and is more resilient to estimation errors. Our results highlight the importance of considering out-of-sample performance risk in designing and evaluating investment strategies and stochastic discount factor models. This paper was accepted by Kay Giesecke, finance. Funding: N. Lassance gratefully acknowledges financial support by the Fonds de la Recherche Scientifique [Grant J.0115.22]. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.00178. [ABSTRACT FROM AUTHOR]

AbstractThis study examines feasibility of incorporating waste hydrated cement paste (WHCP) and luminescent glass (LG) as sand replacements in conventional mortars. Luminescent glass aggregates (LG) were produced by initially mixing luminescent powder with adhesive resin and subsequently adding glass pellets with size smaller than 2 cm. WHCP was produced by mixing cement and water and then cured at room temperature prior to be ground into aggregate with size smaller than 2 mm. Luminescent composite mortars (WLM) were produced by replacing 50–70% of sand by WHCP and LG in which LG replaced 40% of the sand content while WHCP replaced the remaining 10–30%. The feasibility of WLM samples were assessed by their physical and luminescent properties. As results, WLM samples met requirements for constructive mortar such as flowability, drying skrinkage and porosity. At 28d, all WLM samples achieved a strength of around 45 MPa at 28 days, satisfying the strength requirements for constructive mortar. Regarding luminescence properties, all WLM samples exhibited luminescent intensity higher than the threshold of human eyes up to 8h. Luminescent decay curves followed the trend observed in luminescent powders. As such, WLM can be utilized in building projects, particularly for the auxiliary tasks related to road and bridge structures. [ABSTRACT FROM AUTHOR]

The present study focuses on the mechanical performance of steel and polyvinyl alcohol fibers embedded in the geopolymer matrix. A high-strength geopolymer concrete with fly ash, slag and silica fume as precursors and sodium hydroxide and sodium silicate solutions as activators has been tested for its strength in compression and flexure. The influence of fibers on flowability, long-term shrinkage and sulphuric acid attack on the geopolymer concrete has also been studied. The dosage of fibers was maintained at 1%, 2% and 3% by volume, and fibers of length 13 mm have been used in the study. Results indicate that slag with 3% steel fibers by volume had a predominant influence on the strength development of steel fiber-reinforced geopolymer concrete, yielding a compressive strength of 107 MPa after 28 days. Blast furnace slag resulted in increasing the shrinkage of concrete due to rapid gel formation owing to the presence of calcium ions, although the fibers helped reduce the shrinkage to some extent. The strength of steel fiber geopolymer concrete was superior to PVA fiber geopolymer concrete; however, after an acid attack, the strength of steel fiber geopolymer concrete was reduced more than PVA fiber geopolymer concrete due to the enhanced corrosion resistance of PVA fibers. [ABSTRACT FROM AUTHOR]

In the 2nd century AD, Galen argued that the failure to remove any single 'root' of a malignant tumor could result in a local relapse. After nearly 2 millennia, this problem appears to be even more challenging due to our increased understanding of the complexity of tumor formation and spread. Pathological analysis of tumor margins under a microscope remains the primary and only accepted method for confirming the complete tumor removal. However, this method is not an all-or-nothing test, and it can be compromised by various intrinsic and extrinsic limitations. Among the intrinsic limitations of pathological analysis we recall the pathologist handling, tissue shrinkage, the detection of minimal residual disease and the persistence of a precancerous field. Extrinsic limitations relate to surgical tools and their thermal damage, the different kinds of surgical resections and frozen sections collection. Surgeons, as well as oncologists and radiotherapists, should be well aware of and deeply understand these limitations to avoid misinterpretation of margin status, which can have serious consequences. Meanwhile, new technologies such as Narrow band imaging have shown promising results in assisting with the achievement of clear superficial resection margins. More recently, emerging techniques like Raman spectroscopy and near-infrared fluorescence have shown potential as real-time guides for surgical resection. The aim of this narrative review is to provide valuable insights into the complex process of margin analysis and underscore the importance of interdisciplinary collaboration between pathologists, surgeons, oncologists, and radiotherapists to optimize patient outcomes in oral cancer surgery. [ABSTRACT FROM AUTHOR]

\nHIGHLIGHTSThis study focuses on enhancing cementitious materials by incorporating silanized graphene oxide (SGO) and superabsorbent polymers (SAPs), aiming to improve their mechanical and durability properties. The primary goal is to evaluate the effects of SGO/SAP composites on the hydration, absorption, shrinkage, and overall performance of concrete. The composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) to understand their microstructure. Mechanical and durability tests revealed that adding SGO/SAP composites significantly increased the mechanical strength and water absorption capabilities of the concrete. The compressive strength, split tensile strength, and flexural strength of the SGO/SAP-modified concrete were measured at 57 MPa, 4.90 MPa, and 8.25 MPa, respectively. Shrinkage tests demonstrated the composite hydrogel’s excellent water-holding capacity at 0.3 wt.% SGO/SAP, facilitating internal curing in concrete structures. FE-SEM analysis indicated a reduction in microcracks due to the presence of SGO/SAP. The improvements are attributed to the synergistic effects of SGO and SAP, which enhance water retention, dispersion, and interfacial bonding within the cementitious matrix. The microstructural studies confirmed the exceptional stability of the SGO/SAP-modified mix, emphasizing its potential as an additive to improve concrete properties. This research underscores the significant potential of SGO and SAP in advancing the performance of cement-based materials, highlighting their applicability in infrastructure development and construction for creating more durable and high-performing concrete structures. The SGO/SAP significantly enhances the durability of cement-based materials.The SGO/SAPs exhibit superior water absorption and retention properties.Enhanced mechanical strength of SGO/SAP hydrogel-modified concrete.The durability characteristics of cement mortar improved by SGO/SAP hydrogelA decrease in the agglomeration of nanocomposite particlesThe SGO/SAP significantly enhances the durability of cement-based materials.The SGO/SAPs exhibit superior water absorption and retention properties.Enhanced mechanical strength of SGO/SAP hydrogel-modified concrete.The durability characteristics of cement mortar improved by SGO/SAP hydrogelA decrease in the agglomeration of nanocomposite particles [ABSTRACT FROM AUTHOR]

Fused filament fabrication (FFF) is one of the simple and cost-efficient methods of additive manufacturing (AM) of complex objects which has widespread applications in various industries. Developing 3D printing materials is one of the main challenges that scientists are dealing with in this method. Currently, the materials used for 3D printing are amorphous polymers and semi-crystalline polymers that behave similarly to amorphous polymers in the melting process. This is because of the less shrinkage of amorphous thermoplastic materials compared to semi-crystalline polymers which facilitate printing. Since semi-crystalline polymers exhibit better mechanical characteristics compared to amorphous polymers, these materials must be used in the FFF process as well. However, it must be noted that printing these materials is difficult as they show high shrinkage. Particularly, this can be seen by the weak adhesion of the first layer to the bed and the layers' adhesion to each other as a result of high shrinkage. Therefore, this paper aims to assess the feasibility of printing objects from semi-crystalline polymers made of polyoxymethylene (POM). The parameters under study include raster angle, nozzle temperature, filling pattern, filling percentage, and fan mode. The experiments showed that due to high shrinkage, it is not possible to print semi-crystalline parts the same as the parts made of amorphous polymers. However, these parts can be printed by changing the printing direction. Moreover, it is observed that under a specified direction, without the fan, low nozzle temperature, low filling percentage, and 0/90 filling pattern, the semi-crystalline parts are printed more easily. Finally, the mechanical properties of the standard printed samples were evaluated, and the maximum tensile strength, flexural strength, and compressive strength are 11.5, 28, and 8 MPa, respectively. [ABSTRACT FROM AUTHOR]

The mass transfer (diffusion) properties of a colloidal capillary-porous material (pears cut into plates 5 mm thick for convective drying) as a function of the moisture content of the material at different temperatures of the drying agent (air) were studied experimentally. Since the pear sample shrinks significantly during drying, the change in sample thickness during the process was taken into account when calculating the mass conductivity coefficient. At the same time, the linear shrinkage of the specified material was studied. The dependences of the mass conductivity coefficient on the moisture content of the material k = f(u) were obtained from drying curves based on the zonal method at a constant temperature of the drying agent tdr. They represent dependences concave to the abscissa axis that increase with moisture content, which is typical of dried materials. The minimum values of the mass conductivity coefficient on the graphs k = f(u) vary from 0.3∙10–10 m2/s at 30°C to 2.2∙10–10 m2/s at 60°C. With a change in the moisture content of the material, the mass conductivity coefficient changes multiply. The shrinkage data for engineering calculations was described by equation. The possibility of describing the temperature dependence of the mass conductivity coefficient (moisture diffusion) by Arrhenius equation is shown. The values of the Arrhenius equation parameters are obtained. [ABSTRACT FROM AUTHOR]

Introduction1 Drying shrimp is one of the storage methods that, while increasing the shelf life, leads to the production of a versatile product with various uses, from consumption as snacks to use as one of the main components of foods. Drying is preferred over other preservation methods because it offers numerous advantages, including extended shelf life, enhanced microbial stability, convenient consumption, reduced transportation costs, increased value, and product diversity. To accurately model these processes and thus obtain information on factors such as shelf life and energy consumption, it is necessary to determine the product's initial and final temperatures, its geometry and dimensions, and its thermo-physical characteristics. Simulation of different drying processes requires accurate estimation of the effective moisture diffusion coefficient, which is highly dependent on temperature and humidity. Its dependence can be shown by an equation with an Arrhenius structure as an empirical function of humidity and temperature, or by considering the activation energy. It is necessary to have sufficient knowledge about heat and mass transfer characteristics, such as diffusion or penetration coefficient and the heat transfer coefficient to estimate the final temperature and drying time. This study investigated the drying process of peeled farmed shrimp (Litopenaeus vannamei) using a convective hot air dryer. Various parameters such as shrinkage and the effective moisture diffusion coefficient were examined. Materials and Methods A drying device was built to conduct experimental studies on drying shrimp samples. The experiments were conducted on sliced shrimp meat samples at temperatures of 40, 50, and 60 degrees Celsius, with a constant air velocity of 1.5 m/s. The experimental drying models were based on diffusion theory. In these models, it is assumed that the resistance to moisture diffusion occurs from the outer layer of the food. In most cases, Fick's second law was used to describe the phenomenon of moisture penetration. The study used the standard method of immersion in toluene to measure volume changes in the samples. During the drying process, the volume of the samples was measured at 45-minute intervals, and their volume changes were calculated. To measure the moisture content of the samples, each test started by recording the initial weight of the samples using a digital scale with an accuracy of ±0.001 g. During the drying process, the samples were weighed each time their volume was measured. Shrinkage during the drying process is commonly modeled by finding a relationship between shrinkage and moisture, using linear and non-linear models. In most cases, effective permeability is defined as a function of humidity and temperature. For this purpose, curve-fitting methods were employed to analyze the data collected from experimental tests. The appropriate function was extracted by incorporating the Arrhenius equation, which is applicable to most food items. Results and Discussion Based on the results of statistical indices, the linear model was the best model for depicting the relationship between shrinkage changes versus moisture ratio changes among the various experimental models evaluated for shrinkage and drying kinetics. Similarly, the Weibull distribution demonstrated superior performance in expressing variations in moisture ratio over time. A moisture dependent experimental model was used to express the variations in the apparent density of shrimp, resulting in a computed range of 1017-1117 kg m-3. Furthermore, an Arrhenius equation was derived to express the effect of moisture content and temperature on the effective diffusion coefficient of shrimp. According to the results, the effective diffusion coefficient of shrimp exhibited variations ranging from 0.08 ×10-9 m² s-1 to 7.39×10-9 m² s-1. When deriving the effective diffusion coefficient, the impact of the number of terms in Fick's second law on the variation of the moisture ratio was studied. The findings revealed that increasing the number of terms beyond 100 did not significantly affect the model's outputs. Conclusion The linear model had the highest coefficient of determination (R2) among the evaluated shrinkage models, as well as the lowest root mean square error and sum of square error (SSE). This makes it the most optimal model for interpreting shrinkage at the tested temperature levels. The Weibull distribution experimental model proved to be the most suitable for expressing changes in the moisture ratio of shrimp meat slices over time within the evaluated temperature range. The Arrhenius model accurately predicts changes in the effective diffusion coefficient of shrimp slices with respect to temperature and moisture content within the tested temperature range. [ABSTRACT FROM AUTHOR]

The estimation of unknown quantities from multiple independent yet non-homogeneous samples has garnered increasing attention in various fields over the past decade. This interest is evidenced by the wide range of applications discussed in recent literature. In this study, we propose a preliminary test estimator for the common mean (μ) with unknown and unequal variances. When there exists prior information regarding the population mean with consideration that μ might be equal to the reference value for the population mean, a hypothesis test can be conducted: H 0 : μ = μ 0 versus H 1 : μ ≠ μ 0 . The initial sample is used to test H 0 , and if H 0 is not rejected, we become more confident in using our prior information (after the test) to estimate μ. However, if H 0 is rejected, the prior information is discarded. Our simulations indicate that the proposed preliminary test estimator significantly decreases the mean squared error (MSE) values compared to unbiased estimators such as the Garybill-Deal (GD) estimator, particularly when μ closely aligns with the hypothesized mean ( μ 0 ). Furthermore, our analysis indicates that the proposed test estimator outperforms the existing method, particularly in cases with minimal sample sizes. We advocate for its adoption to improve the accuracy of common mean estimation. Our findings suggest that through careful application to real meta-analyses, the proposed test estimator shows promising potential. [ABSTRACT FROM AUTHOR]

Hybrid cements combine clinker with large amount of supplementary cementitious materials while utilizing hydration and alkali activation processes. This paper summarizes shrinkage and creep properties of industrially produced H-cement, containing only 20% of Portland clinker. In comparison with a reference cement CEM II/B-S 32.5 R, autogenous shrinkage is smaller after 7 days, and drying shrinkage is similar at similar times. A different capillary system of H-cement leads to faster water mass loss during drying. Basic and total creep of concrete remains in the standard deviation of B4 and EC2 creep models. The results demonstrate that shrinkage and creep properties of concrete made from H-cement have similar behavior as conventional structural concrete or high-volume fly ash concrete. [ABSTRACT FROM AUTHOR]

Machine learning (ML) methods present a valuable opportunity for modeling the non-linear behavior of the injection molding process. They have the potential to predict how various process and material parameters affect the quality of the resulting parts. However, the dynamic nature of the injection molding process and the challenges associated with collecting process data remain significant obstacles for the application of ML methods. To address this, within this study, hybrid approaches are compared that combine process data with additional process knowledge, such as constitutive equations and high-fidelity numerical simulations. The hybrid modeling approaches include feature learning, fine-tuning, delta-modeling, preprocessing, and using physical constraints, as well as combinations of the individual approaches. To train and validate the hybrid models, both the experimental and simulated shrinkage data of an injection-molded part are utilized. While all hybrid approaches outperform the purely data-based model, the fine-tuning approach yields the best result in the simulation setting. The combination of calibrating a physical model (feature learning) and incorporating it implicitly into the training process (physical constraints) outperforms the other approaches in the experimental setting. [ABSTRACT FROM AUTHOR]

This research examines the influence of high-volume fly ash (HVFA) on reinforced concrete (RC) beam deflections over 180 days of continuous loading. The study comprises eight fly ash-based concrete mixes with varying fly ash ratios (0–60%). Experimental assessments were conducted on two load levels, corresponding to 25% and 50% of the initial cracking load. Thirty-two full-scale RC beams, each measuring 100 × 150 × 1800 mm, were fabricated for both load levels. Long-term deflections were monitored for all concrete mixes through sustained four-point bending tests at ages ranging from 1 to 180 days. A comparative analysis of the overall mid-span deflection between conventional and fly ash concrete RC beams was carried out against established design codes. It was determined that high-volume fly ash RC beams exhibited less creep and shrinkage deflection compared with conventional RC beams. Moreover, artificial neural network (ANN) modelling was also carried out to propose a significant model helpful in predicting the total deflection of RC beams containing any fly ash content and at any age of concrete. The present study offers valuable insights for engineers and designers, facilitating the evaluation of age-dependent deflection patterns in RC beams constructed with reinforced high-volume fly ash concrete. [ABSTRACT FROM AUTHOR]

The present study examined the impact of ethanol pretreatment and drying time on various aspects, including drying characteristics, modeling using thin-layer and artificial neural network (ANN) approaches, color changes during the drying process, shrinkage ratio, total phenolic content (TPC), and antioxidant activity (AA) analysis, as well as ATR-FTIR analysis and principal component analysis (PCA) of the potato slices. Ethanol concentration and pretreatment time had an incredible effect on drying rate and drying time. Higher ethanol concentration and longer pretreatments time provided shorter drying time and a more rapid drying rate. On the other hand, ANN modeling of the potato slices showed better prediction than thin-layer modeling. According to the total color difference (ΔE) values of the samples, ethanol pretreatments had a negative contribution to color properties. Furthermore, the shrinkage ratio of potato samples was affected by drying and ethanol pretreatment time. Diameter shrinkage increased with the increment in ethanol concentration and pretreatment time. TPC and AA of the potato slices showed to decreasing tendency during the drying process. The highest loss of TPC and AA was observed from the samples coded 60 °C + 100 ET 15 and 60 °C + 100 ET 30. Additionally, ATR-FTIR and PCA analysis well exhibited the effect of the ethanol pretreatment and drying process on the composition of the potato slices. [ABSTRACT FROM AUTHOR]

We study the effect of population change on subjective wellbeing (SWB) using over 100,000 observations from behavioral risk factor surveillance system representative of 392 US counties. SWB correlates higher with population change (0.4) than with county-level crime (-0.25) and income (0.2). The relative ecological strong effect size holds in regressions controlling for person-level and county-level predictors of SWB-population change is one of the strongest ecological predictors of SWB. While ecological variables have a smaller effect on individual SWB than person-level variables, their total combined population effect is large. This is only the second study on the effect of population change of a city/county on its residents' happiness. Such a gap in the literature is remarkable—we call for more research in this area and present directions for future research. As in any nonexperimental study, results are not causal. And results may not generalize beyond the US population studied. [ABSTRACT FROM AUTHOR]

The effects of the addition of nanoparticles (NPs) of alumina (NA) and silica (NS) on the rheological properties of aqueous-based ceramic inks for material extrusion-based additive manufacturing (ME-AM) and sinterability of printed ceramic components were investigated. The inks were first designed using bimodal particle sizes of NPs with micro-alumina, and their solids fraction in printable inks was found to be dependent on the functionalization properties of NPs. NAs create a lubricating effect in the ink system and improve solids-loading in the ink. Meanwhile, NSs form silanol bonds in aqueous-based inks that increase viscosity and reduce solids-loading for a printable ME-AM ink. The inks containing NPs with higher solids-loading and optimized rheology were printed using ME-AM, and the printed components were sintered at 1400–1550 ºC. Adding NPs in the ink significantly improved the sinterability of printed shapes by enhancing sintering kinetics and filling-effects, with NS having a more significant effect than NA. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents the results of the experimental evaluation of four nonproprietary ultra-high-performance concrete (UHPC) mixture proportions currently being used for industrial applications by various precast concrete producers across the United States and Canada. The main objective of this research was to acquire data about the effects that creep and shrinkage phenomena produced with UHPC materials. Shrinkage was assessed by the ASTM C157 testing method modified by ASTM C1865 and ASTM C1698. Creep was evaluated by the ASTM C512 testing method modified by ASTM C1856. Results for creep and shrinkage strains and creep coefficient are presented and discussed. Comparisons with conventional concrete are also made. This detailed characterization of creep and shrinkage properties of the nonproprietary UHPC mixture proportions advances the understanding of UHPC materials and phenomena and offers useful information for further research on applications of UHPC for prestressed concrete structural components. [ABSTRACT FROM AUTHOR]

The formation of defects, due to drying, in robocasted ceramic objects is an important issue arising from non-uniform shrinkage of the material during this step in the process. Common methods for shrinkage measurement are not well suited to the small size of robocasted cords or the complexity of robocasted objects. Innovative methods for shrinkage measurement were developed using non-destructive optical vision techniques with computer-controlled data acquisition, allowing measurement on millimetric cords and on specific zones of a product. The study of a single porcelain cord revealed an anisometric shrinkage related to the orientation of grains during extrusion. A differential shrinkage at the macroscopic scale was also measured on a robocasted object, indicating a moisture content gradient in the material. The methods presented in this paper are of particular relevance to real-time control of the drying process for robocasted objects. [ABSTRACT FROM AUTHOR]

Meta‐analyses are commonly performed based on random‐effects models, while in certain cases one might also argue in favor of a common‐effect model. One such case may be given by the example of two "study twins" that are performed according to a common (or at least very similar) protocol. Here we investigate the particular case of meta‐analysis of a pair of studies, for example, summarizing the results of two confirmatory clinical trials in phase III of a clinical development program. Thereby, we focus on the question of to what extent homogeneity or heterogeneity may be discernible and include an empirical investigation of published ("twin") pairs of studies. A pair of estimates from two studies only provide very little evidence of homogeneity or heterogeneity of effects, and ad hoc decision criteria may often be misleading. [ABSTRACT FROM AUTHOR]

Nowadays, the construction industry requires an ample quantity of non-renewable materials resulting in the excavation of natural beds and thus creating an imbalance in our environment. Besides this, plenty of waste material such as plastic waste in the forms of powder, fiber, etc. is produced daily. Sustainable disposal of this waste has appeared as a tough task across the world. The current work was undertaken to reduce the issue of plastic waste mainly polyethylene terephthalate, disposal by its effective utilization in cement mortar mixes without affecting their physical, chemical, mechanical, durability, and microstructural properties. For this, a total of ten cement mortar mixes with 1:3 and 1:6 mix proportions were prepared by using polyethylene terephthalate plastic waste [1mm (68%), 2mm (22%), 3mm (6%), and 4mm (4%)] in place of fine aggregate upto 20% replacement at an interval of 5%. These mortar mixes were evaluated for their workability, water absorption, compressive strength, flexural strength, acid attack, and shrinkage properties. Effects on internal structure were monitored by microstructural analysis such as Xray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy techniques. With 5% polyethylene terephthalate instead of river sand, the mixes displayed improved strength with the highest recorded 8.03 MPa and 2.36 MPa for 1:3 and 1:6 mixes respectively, and also obtained workability with increased density and homogeneity of structure. Benefits from polyethylene terephthalate were confirmed through microstructural analysis techniques except that there was a reduction in drying shrinkage. The results recommend that polyethylene terephthalate can be a reliable material in advanced construction applications offering enhanced structural parameters to save natural resources. [ABSTRACT FROM AUTHOR]

This study first examines changes in the amount of residential area on a regional scale, which is said to shrink following population decline, using Japan as an example, where population decline is already underway in most of the country. Second, it examines how the regional governments have set future targets for residential areas and whether these targets are consistent with the current trend. Third, it examines how prefectures, Japan's regional governments, are responding to this situation through regional land use planning. The methodologies of the paper are a combination of collecting and sorting out the related data, reviewing and extracting information from planning documents, and conducting interviews with persons in charge. In conclusion, residential areas have continued to increase on a regional scale, even as the population has declined. Shrinkage does not follow population decline on a regional scale. It was also found that the amount of residential area changed more closely with the change in households than with the population. National and regional land use plans generally set targets for more shrinkage than the actual trend. The underestimation of the amount of residential area was due to the rapid decline in the number of persons per household. Cases of the three prefectures showed that specific control is left to the individual acts, while the measures are indicated in the wording by the prefectural land use plans. [ABSTRACT FROM AUTHOR]

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Three-dimensional polymeric network of hydrogels avoids its dissolution into the aqueous region. Hydrogels must have strong structural integrity to be used for drug/nutraceutical delivery. A three factor-three-level Box-Behnken design was used to understand the effects of starch concentration, NaCl, and pH on the textural and structural integrity of Lysine modified kutki millet starch hydrogels. Various kinetic models were fitted to the time-course measurement of shrinkage behavior of both conventionally (CDHG) and freeze-dried (FDHG) hydrogel. Increasing the swelling temperature (5–50 °C) showed values of higher molecular weight of polymer chains between neighboring crosslinks ( M c) ¯ (g/mol) for FDHG (9539.59–56,769.72) than CDHG (1096.28–11,420.48). Similarly, mesh size (ξ) was more for FDHG (38.63–109.53 Ȧ) than CDHG (10.97–42.74 Ȧ). However, other network parameters such as polymer volume fraction ( ∅ p ) was lower for FDHG (0.229-0.146) than CDHG (0.3882–0.222). These values suggest low swelling power of CDHG compared to FDHG. Thermodynamically, FDHG took less energy to swell than CDHG. The study showed that FDHG has better properties than CDHG and could be employed in nutraceutical delivery. [ABSTRACT FROM AUTHOR]

Rubberized cement-based materials are widely utilized because of their good ductility, impact resistance, and fatigue resistance. This research investigated the effect of the rubber aggregates content, particle size of rubber aggregates, and water–cement ratio on the early-age mechanical properties and deformation behaviors of mortar through laboratory tests, and strength reduction coefficient fitting models were established according to the testing results. The results show that the compressive strength growth rate of cement mortar is about 15% slower than that of flexural strength. The existence of rubber aggregates lowers the strength increase rate of mortar. The reduction coefficient of strength decreases with increasing rubber aggregates content and increases with the age of mortar. Increasing rubber aggregates content and decreasing particle size of rubber aggregate can lower the autogenous shrinkage in the initial stage, but the autogenous shrinkage of the later stage increases as the rubber aggregates content increases, with a turning point between 30 h and 50 h. After 3 days, the dry shrinkage of mortar accounts for about 70–80% of the total shrinkage, and it increases with higher rubber aggregate content, smaller particle size of rubber aggregates, and higher water–cement ratios. [ABSTRACT FROM AUTHOR]

The semirigid pavement base is known for its high strength and good stability. However, it faces challenges owing to the generation of shrinkage stress during the development of its strength subsequent service. This stress arises from internal changes in relative humidity and temperature. When this shrinkage stress exceeds the bonding force of the cementitious material, the base may develop dry shrinkage cracks and temperature shrinkage cracks. Addressing this issue, cementitious material based on red mud emerges as a novel solution for roadbed construction, potentially replacing traditional cement entirely. Despite its promise, the crack resistance evolution of this material is still unclear. This study focuses on the dry shrinkage and temperature shrinkage properties of the stabilized gravel layer made from red mud-based cementitious material. It investigates how various factors, including the content of red mud-based cementitious material and duration of maintenance, affect these shrinkage properties. Additionally, it establishes a correlation between dry shrinkage, temperature shrinkage, and their maximum strain values through grey correlation degree analysis. Experimental results reveal a positive correlation between the cumulative dry shrinkage strain of stabilized crushed stone based on red mud cementitious material and the curing age, with the growth rate diminishing over time. The cumulative dry shrinkage strain first decreases and then increases as the content of red mud cementitious material rises, hitting its lowest point at 7% content. The cumulative dry shrinkage coefficient of stabilized crushed stone of red mud–based cementation material reaches the peak value at the age of 1 d and before gradually decreasing and stabilizing. Notably, at an 8% dosage, this coefficient is significantly higher than in other groups. Regarding temperature shrinkage, the coefficient first increases and then decreases with rising temperature. The average temperature shrinkage coefficient follows a similar pattern based on the content of red mud-based cementitious material, with the 7-day coefficient substantially exceeding the 28-day figure. Microcracks fill the stable gravel matrix at 7 days of age, whereas at 28 days, the matrix becomes denser owing to the increase in hydration products. Scanning electron microscope morphology analysis further elucidates the mechanisms of dry and temperature shrinkage. Employing grey relational analysis, the study identifies the dry shrinkage resistance index and temperature shrinkage coefficient as optimal indicators for assessing the cracking resistance of stabilized crushed stone using red mud-based cementitious material. Optimal cracking resistance is achieved when the content of red-mud cementitious material is 7%.

This research explores multi-objective optimization in injection molding with a focus on identifying the optimal configuration for the moldability index in aviation propeller manufacturing. The study employs the Taguchi method and fuzzy analytic hierarchy process (FAHP) combined with the Technique for the Order Performance by Similarity to the Ideal Solution (TOPSIS) to systematically evaluate diverse objectives. The investigation specifically addresses two prevalent defects—shrinkage rate and sink mark—that impact the final quality of injection-molded components. Polypropylene is chosen as the injection material, and critical process parameters encompass melt temperature, mold temperature, filling time, cooling time, and pressure holding time. The Taguchi L25 orthogonal array is selected, considering the number of levels and parameters, and Finite Element Analysis (FEA) is applied to enhance precision in results. To validate both simulation outcomes and the proposed optimization methodology, Artificial Neural Network (ANN) analysis is conducted for the chosen component. The Fuzzy-TOPSIS method, in conjunction with ANN, is employed to ascertain the optimal levels of the selected parameters. The margin of error between the chosen optimization methods is found to be less than one percent, underscoring their suitability for injection molding optimization. The efficacy of the selected optimization method has been corroborated in prior research. Ultimately, employing the fuzzy-TOPSIS optimization method yields a minimum shrinkage value of 16.34% and a sink mark value of 0.0516 mm. Similarly, utilizing the ANN optimization method results in minimum values of 16.42% for shrinkage and 0.0519 mm for the sink mark. Doi: 10.28991/ESJ-2024-08-05-025 Full Text: PDF

IntroductionDrying shrimp is one of the storage methods that, while increasing the shelf life, leads to the production of a versatile product with various uses, from consumption as snacks to use as one of the main components of foods. Drying is preferred over other preservation methods because it offers numerous advantages, including extended shelf life, enhanced microbial stability, convenient consumption, reduced transportation costs, increased value, and product diversity.To accurately model these processes and thus obtain information on factors such as shelf life and energy consumption, it is necessary to determine the product’s initial and final temperatures, its geometry and dimensions, and its thermo-physical characteristics. Simulation of different drying processes requires accurate estimation of the effective moisture diffusion coefficient, which is highly dependent on temperature and humidity. Its dependence can be shown by an equation with an Arrhenius structure as an empirical function of humidity and temperature, or by considering the activation energy.It is necessary to have sufficient knowledge about heat and mass transfer characteristics, such as diffusion or penetration coefficient and the heat transfer coefficient to estimate the final temperature and drying time. This study investigated the drying process of peeled farmed shrimp (Litopenaeus vannamei) using a convective hot air dryer. Various parameters such as shrinkage and the effective moisture diffusion coefficient were examined.Materials and MethodsA drying device was built to conduct experimental studies on drying shrimp samples. The experiments were conducted on sliced shrimp meat samples at temperatures of 40, 50, and 60 degrees Celsius, with a constant air velocity of 1.5 m/s. The experimental drying models were based on diffusion theory. In these models, it is assumed that the resistance to moisture diffusion occurs from the outer layer of the food. In most cases, Fick's second law was used to describe the phenomenon of moisture penetration.The study used the standard method of immersion in toluene to measure volume changes in the samples. During the drying process, the volume of the samples was measured at 45-minute intervals, and their volume changes were calculated. To measure the moisture content of the samples, each test started by recording the initial weight of the samples using a digital scale with an accuracy of ±0.001 g. During the drying process, the samples were weighed each time their volume was measured.Shrinkage during the drying process is commonly modeled by finding a relationship between shrinkage and moisture, using linear and non-linear models. In most cases, effective permeability is defined as a function of humidity and temperature. For this purpose, curve-fitting methods were employed to analyze the data collected from experimental tests. The appropriate function was extracted by incorporating the Arrhenius equation, which is applicable to most food items.Results and DiscussionBased on the results of statistical indices, the linear model was the best model for depicting the relationship between shrinkage changes versus moisture ratio changes among the various experimental models evaluated for shrinkage and drying kinetics. Similarly, the Weibull distribution demonstrated superior performance in expressing variations in moisture ratio over time. A moisture dependent experimental model was used to express the variations in the apparent density of shrimp, resulting in a computed range of 1017-1117 kg m-3. Furthermore, an Arrhenius equation was derived to express the effect of moisture content and temperature on the effective diffusion coefficient of shrimp. According to the results, the effective diffusion coefficient of shrimp exhibited variations ranging from 0.08 ×10-9 m2 s-1 to 7.39×10-9 m2 s-1. When deriving the effective diffusion coefficient, the impact of the number of terms in Fick's second law on the variation of the moisture ratio was studied. The findings revealed that increasing the number of terms beyond 100 did not significantly affect the model’s outputs.ConclusionThe linear model had the highest coefficient of determination (R2) among the evaluated shrinkage models, as well as the lowest root mean square error and sum of square error (SSE). This makes it the most optimal model for interpreting shrinkage at the tested temperature levels. The Weibull distribution experimental model proved to be the most suitable for expressing changes in the moisture ratio of shrimp meat slices over time within the evaluated temperature range. The Arrhenius model accurately predicts changes in the effective diffusion coefficient of shrimp slices with respect to temperature and moisture content within the tested temperature range.

This paper presents four parameters in 3D Printing Concrete (3DPC) in the fresh state. Flowability, extrudability, open time, and buildability. In addition, this paper also introduces a new method to obtain the green strength of fresh concrete. The high-strength concrete mixture was used as a base mix design. The water to binder ratio and admixture were tuned to obtain the 3DPC that satisfied those four parameters. The 3DPC mix design used cement, silica fume, and reactive powder as a binder with a ratio of 3:1:1. The ratio of sand and binder was 0.9. The water to binder ratio (w/b) was 0.14 with the addition of a superplasticizer and accelerator. To increase the buildability, polyvinyl alcohol (PVA) fiber was added by 0.2% of concrete volume. It had a 30 mm slump, 110 mm flow, 1.1 SRF, 85 minutes of open time, and 7 KPa green strength in 75 minutes. This mix design was able to be printed into 40 layers of 100×400 mm cylinder.

The presence of reliable techniques for predicting the stress state in composite materials is one of the most important requirements in the design of composite components and structures. An analytical model has been developed to evaluate the shear stresses at the substrate-coating interface in tensile testing of a flat specimen. The developed model has been verified by numerical simulation. The strength and mechanisms of the fracture of furan epoxy composite coatings with polyvinyl chloride and zinc oxide fillers with various concentrations were studied. The adhesion strength of furan epoxy composite coatings with metal substrate was determined by the pull-off test of cylindrical specimens and the tensile test of flat-coated specimens. The correlation between the measured values of fracture stresses for two types of tests of composite coatings was determined. It is concluded that for qualitative comparison of fracture stress in composite coatings it is possible to neglect stress concentration in the specimens. The analyzed methods of stress evaluation have the same trends in the change of the measured values for different composite coatings. However, considering the stress concentration in the specimens provides more accurate results in determining the strength characteristics. [ABSTRACT FROM AUTHOR]

This study examines the effects of varying ultraviolet (UV) exposure times on the properties of UDMA/TEG-DMA composite resins, focusing on degree of conversion, surface morphology, water absorption, shrinkage, hardness, and flexural strength. Composite resin samples were exposed to UV light for 30, 60, 90, and 120 min. The degree of conversion was assessed using Fourier Transform Infrared Spectroscopy (FTIR). Surface morphology was analyzed via Scanning Electron Microscopy (SEM). Water absorption and shrinkage were measured following standard procedures, while mechanical properties, including hardness and flexural strength, were evaluated using a Vickers hardness tester and a 3-point bending test, respectively. The results indicate that a UV exposure time of 90 min optimizes the composite resin properties, achieving the highest degree of conversion at 77 %, optimal surface morphology, minimal water absorption and shrinkage, and superior mechanical properties, including maximum flexural strength and hardness. In contrast, both shorter and longer UV exposure times detrimentally affected these properties, with prolonged exposure causing thermal degradation and reduced performance. This research underscores the importance of precise UV curing time control to enhance the performance and durability of UDMA/TEG-DMA composite resins, providing valuable insights and practical guidelines for their application in dental and industrial fields. [ABSTRACT FROM AUTHOR]

This study uses statistical learning methods to identify robust coverage alternatives for the Pasture, Rangeland, Forage (PRF) insurance program. Shrinkage and ensemble learning techniques are adapted to the context of the PRF coverage selection process. The out‐of‐sample performance of the proposed methods is evaluated on 116 representative grids throughout Texas during 2018–2022. Ensemble learning methods generated more stable coverage choices compared with the other selection strategies considered. Depending on the target return, a reduction in the prediction error between 5% and 14% was observed. Furthermore, the proposed coverages can provide a broader protection than current coverage choices made by farmers. [ABSTRACT FROM AUTHOR]

The drying and storage process in jelly candy present a significant challenges due to their impact on stability. This study investigates the drying kinetics and moisture sorption isotherms of jelly candy. The aim of the study focuses on comparing the effectiveness of conventional models (Courie-GAB-Peleg) and artificial neural networks (ANN) in analyzing the sorption behaviour of jelly candy, specifically when corn stract was added. In addition, the drying characteristics, shrinkage, and storage recommendations of jelly candies were also identified. The static gravimetric method uses a saturated solution of sulfuric acid with 13 (thirteen) different concentrations to condition the water activity (aw) in the range of 0.06–0.89 (25–35 °C). In addition, the oven drying processed at a temperature of 40–60 °C with an air speed of 3.6 m/s. The study results show that the final equilibrium moisture content (EMC) of drying has a range of 19.74%w.b-22.02%w.b, and the highest drying rate is 0.11%w.b/min-0.27%w.b/min. At the end of dryng, shrinkage of jelly candy is 22-33% compared to initial conditions. Based on the model accuracy test, it shows that the Peleg model was identified as the best model. The correlation between drying kinetic and moisture sorption was explained with storage recommendations and its recommendation for good jelly candy storage is 24.19%w.b. These storage recommendations were used to determine the appropriate stop of the drying process to minimize drying time. [ABSTRACT FROM AUTHOR]

This work focuses on dimension-reduction techniques for modelling conditional extreme values. Specifically, we investigate the idea that extreme values of a response variable can be explained by nonlinear functions derived from linear projections of an input random vector. In this context, the estimation of projection directions is examined, as approached by the extreme partial least squares (EPLS) method—an adaptation of the original partial least squares (PLS) method tailored to the extreme-value framework. Further, a novel interpretation of EPLS directions as maximum likelihood estimators is introduced, utilizing the von Mises–Fisher distribution applied to hyperballs. The dimension reduction process is enhanced through the Bayesian paradigm, enabling the incorporation of prior information into the projection direction estimation. The maximum a posteriori estimator is derived in two specific cases, elucidating it as a regularization or shrinkage of the EPLS estimator. We also establish its asymptotic behavior as the sample size approaches infinity. A simulation data study is conducted in order to assess the practical utility of our proposed method. This clearly demonstrates its effectiveness even in moderate data problems within high-dimensional settings. Furthermore, we provide an illustrative example of the method’s applicability using French farm income data, highlighting its efficacy in real-world scenarios. [ABSTRACT FROM AUTHOR]

The formation of defects, due to drying, in robocasted ceramic objects is an important issue arising from non-uniform shrinkage of the material during this step in the process. Common methods for shrinkage measurement are not well suited to the small size of robocasted cords or the complexity of robocasted objects. Innovative methods for shrinkage measurement were developed using non-destructive optical vision techniques with computer-controlled data acquisition, allowing measurement on millimetric cords and on specific zones of a product. The study of a single porcelain cord revealed an anisometric shrinkage related to the orientation of grains during extrusion. A differential shrinkage at the macroscopic scale was also measured on a robocasted object, indicating a moisture content gradient in the material. The methods presented in this paper are of particular relevance to real-time control of the drying process for robocasted objects.

Recycling used face masks into useful products is an alternative way to reduce the accumulation of medical waste during the COVID-19 period. The main objective of this study was to determine the effect of injection molding parameters of barrel temperature, molding temperature, and cooling time on tensile strength and plastic shrinkage during the recycling process of used disposable face masks. The study utilized a Design of Experiment (DoE) using the Taguchi Orthogonal L9 method. In this current study, the barrel temperatures were set at 170oC, 190oC, and 220oC. with the molding temperatures used are 45°C, 60°C, and 75°C, while the values of cooling time were 26s, 43s, and 52s. The tensile test was carried out according to the ASTM D638 type V standard for measuring the strength of materials. The findings demonstrate that the most important factor in achieving the highest tensile strength is the molding temperature, which contributes 34.54% and is best combined with a barrel temperature of 170°C, a molding temperature of 60°C, and a cooling period of 52s. By contributing 54.40% to the parameter combination of barrel temperature of 170°C, molding temperature of 45°C, and cooling time of 52s, the molding temperature becomes the most crucial factor to produce the least amount of shrinkage

Making molds in the injection molding manufacturing process is one of the basic steps that functions to prevent product defects during the production process. The product defects that most often occur in this manufacturing process include shrinkage and warpage defects. This research will discuss the mold design for the APC SF 11x4.7 propeller product with a twist variation of 45o and minimum shrinkage and warpage values. Glass Fiber Reinforced Polypropylene (GFRPP) will be used as the propeller product material. The entire design process to testing will be carried out using software assistance. The Taguchi method with an L9 orthogonal array matrix (34) was used in this research. where L9 explains that the experiment will be carried out nine times, and 34 means there are three levels and four main factors. The four main factors consist of packing pressure, packing time, melting temperature and injection pressure. The Taguchi method is used with the aim of making it easier to find the variation value that produces the lowest shrinkage and warping defects in the product. The simulation results show that the variation with the smallest shrinkage value produces a value of 7.9% and the variation with the smallest warpage value produces a value of 1.051 mm

Cellulose films, predominantly consisting of micro-nanocelluloses, are a new type of product with interesting properties for functional packaging applications. However, the potentially scalable production methodology has not yet been elucidated. Poor dewatering and high web shrinkage are issues that need solutions beyond what is available in conventional paper production. This research investigates a cyclic pressing method that shows potential in cellulose film consolidation. Cyclic pressing allows the MNFC films to be dewatered to about 90% solids while yielding a smooth, flat product. The results show no inherent physical limits for mechanical dewatering these high swelling webs, even at very high solids. Cyclic pressing allows controlled restraint during consolidation, which could be adjusted in an industrial setup to produce even films with desirable product characteristics.

The dependence of the properties of elastic sensitive elements made of beryllium bronze on the modes of their heat treatment is studied. It is shown that the duration of aging significantly affects the value of nonlinearity of elastic characteristic, hysteresis, shrinkage of elements and mechanical properties of membrane material (hardness, elastic limit). The relations between submicroscopic structure and properties of elastic elements are established. The greatest nonlinearity of the elastic characteristic, hysteresis and shrinkage belong to elements subjected to short-term aging at 310–350 °С. With increasing duration of aging, the corresponding values of the above parameters decrease. For aging temperatures 310–320 °С, the nonlinearity of elasticity characteristics reaches the minimum values after 4–5 h of aging, and for 340 °С — after 3 h. At 350 °С minimum values of nonlinearity are reached after aging duration of 45–60 min. From the obtained data it follows that from the point of view of obtaining the minimum hysteresis and nonlinearity characteristics of aneroid sensing elements made of bronze of БрБНТ-1,9Мг (BrBNT-1.9Mg) grade, heat treatment of membranes should be carried out according to the regimes of 1 h at 350 °С or 3 h at 340 °С.

In mass production, injection molding plays a vital role in manufacturing various parts with complex settings. As perfluoroalkoxy alkane (PFA) injection‐molded products are widely used in immersion system, dimensional quality needs more attention. However, there is limited research on the dimension defects of PFA injection‐molded products. This study focused on the influence of mold design and process parameters on PFA part shrinkage, using mold flow simulation and orthogonal testing separately. Several gate locations and sizes were simulated to minimize shrinkage in mold design. Displacements varied with gate locations, and shrinkage decreased with larger gate sizes. The Taguchi method analyzed process parameters' impact on shrinkage. The results indicated that the injection rate had the most significant effect on the shrinkage of tube length, while melt temperature, holding pressure, and screw speed affected the shrinkage of tubes' outside diameter. Different flow directions exhibited variance in shrinkage. Using max–min normalization, the two shrinkage values reached 0.00972, whereas the smallest value obtained in the orthogonal experiment was 0.1545 in run 3. Thus, optimizing mold design and process parameters were two effective methods to reduce shrinkage. This study reduced shrinkage and improved the quality of PFA injection molding parts for semiconductor systems. [ABSTRACT FROM AUTHOR]

Bamboo is increasingly used as an alternative material for producing renewable and environmentally friendly products. Bamboo should be dried before use to increase its stability and improve its resistance against biodeterioration agents. The most common drying method for bamboo is through air-drying. Alternatively, artificial drying, such as solar drying, can produce optimum drying results regarding the drying rate and quality of bamboo throughput. This study investigated the potential utilisation of solar drying methods for processing local bamboo. The drying characteristics and physical and mechanical properties of solar-dried Gigantochloa levis bamboo culms' bottom, middle, and top sections were determined. The drying time of G. levis culm has been reduced to about 40 days compared to the conventional air drying of 70 days using the solar-assisted kiln dryer. Solar-dried culms have a lower final moisture content of 20% than air-dried ones. The average circumference and diameter shrinkage values of solar-dried G. levis culms from green to approximately 12% moisture content were 3.22% and 4.29%, respectively, and the wall thickness shrinkage was 8.12%. The mean values of modulus of rupture and modulus of elasticity of solar-dried G. levis culm were 63.75 and 12567.99 N mm-2, respectively, while its mean values of compression and shear parallel to fibre were 45.87 and 10.01 N mm-2, respectively. The quality of solar-dried G. levis culms produced in this study showed the viability of using a solarassisted kiln-dryer as a potential alternative processing method for drying local bamboo species in Malaysia. [ABSTRACT FROM AUTHOR]

The current study introduces porous ceramic materials fabricated from cenospheres through spark plasma sintering. The investigation delves into the impact of sintering temperature, mould diameter (20 and 30 mm), and cenosphere size on the resulting material properties. Notably, sample shrinkage initiates at 900 °C and demonstrates an upward trend with temperature escalation, while a larger mould diameter contributes to sample shrinkage. Elevated sintering temperature leads to increased apparent density across various sample series, such as CS 63–150 µm in a 20 mm mould (0.97 to 2.3 g/cm³ at 1050–1300 °C), CS 150–250 µm in a 20 mm mould (0.93 to 1.96 g/cm³ at 1050–1200 °C), and others in different mould sizes. Total porosity decreases from 61.5 % to 3.9 % with a rising sintering temperature (1050 to 1250 °C), while open porosity starts decreasing at lower temperatures. Closed porosity peaks in samples sintered at 1150 °C. Furthermore, an increase in sintering temperature from 1050 to 1300 °C boosts the compressive strength of CS 63–150 samples in a 20 mm mould from 11 MPa to 312 MPa. These findings align with the Rice model, illustrating an exponential relationship between compressive strength, material porosity, and fully dense material compressive strength. [ABSTRACT FROM AUTHOR]

The existing creep and shrinkage models used for predicting long‐term behavior of prestressed concrete (PSC) beams are originally developed for cylinders under axial compression. This experimental study investigates the creep behavior in axial and flexural compression and attempts to verify the suitability of the standard models for application in PSC beams. The study is carried out by monitoring the strains and the prestress losses in four PSC beams having the same cross‐section, subject to prestress loading alone, and the strains in two axially loaded cylinders, under ambient environmental conditions for a duration of 365 days. The effects of drying, stress gradient across the depth, bonding of prestressing steel, and high reinforcement have been considered. The experimental results have been compared with the predictions by six standard models (AASHTO, ACI 209R‐92, GL 2000, B3, MC2010, and Eurocode model). For the PSC beams, the predictions from standard models are based on a numerical three‐dimensional finite element model that accounts for the stress variation with time due to prestress loss and the effect of reinforcement. The results show that creep behavior in flexural compression is different from that in axial compression and most of the standard models over‐estimate the strains in PSC beams considered in the present study. The study also provides an overview of the relative accuracies of the standard models and has practical relevance in the design of PSC bridges and estimation of prestress loss. [ABSTRACT FROM AUTHOR]

Karal soils mainly composed of swelling clays are considered as one of the main causes of degradation in civil engineering structures in Cameroon. Thus, a better knowledge on Karal-type soil behavior is required to adapt soil treatment for road construction and foundation dimensioning. The physicochemical, mineralogical and geotechnical characterization of ten soils collected in North and Far North Cameroon allowed to classify Karal among plastic soils. As expected, the optimum water contents and maximum dry densities of dynamically compacted Karal reflected the particle size distribution and the mineralogical soil composition with various amounts of swelling clay (montmorillonite) and quartz associated to sand and silt fractions. Then the swelling/shrinkage properties of compacted specimens evaluated by free swelling test and volume shrinkage test were correlated to soil characteristics to propose a suitable classification for Karal-type soils. Not only swelling but also shrinkage properties were assessed and combined to define a new parameter called the total amplitude of swelling and shrinkage deformation, allowing the exclusion of the soil initial water content when evaluating soil deformation. After comparison of usual indirect methods to classify swelling soils, a predictive method of clay-rich soils deformation under moisture variation for Karal was proposed and discussed. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of quarry waste sand (QWS) on the physical and mechanical properties of recycled aggregates concrete (RAC). Two sets of concretes were made one with natural sand (NS) and another with QWS sand. Five mixes with replacement ratios of 20%, 40%, 60%, 80% and 100% of ordinary coarse aggregates (OCA) by recycled concrete aggregates (RCA) were produced for each set. Tests were performed to determine slump, compressive strength, flexural strength, water absorption by immersion and shrinkage. The results showed that the mixes produced with QWS sand exhibited slightly better fresh and hardened properties. The combination of QWS sand and RCA aggregates reduces the degradation often recorded and makes RAC concrete to have the same level of performance as concrete with ordinary aggregates. Some relationships were deduced to express each performance of QWS sand-based concrete with that of NS sand-based concrete. This makes the use of this sand very practical and its modifications easily quantifiable. [ABSTRACT FROM AUTHOR]