Material Moisture Research Articles

Production-Process Simulation and Life-Cycle Assessment of Metakaolin as Supplementary Cementitious Material

An environmental assessment of metakaolin as a supplementary cementitious material (SCM) through an integrated production-process-simulation and Life-Cycle-Assessment (LCA) approach is presented in this work. Initially, process simulation models were developed to reproduce the basic stages of the metakaolin production process. The effect of various operational parameters and scenarios, such as calcination temperature, moisture of raw material and associated drying, exhaust gas recirculation and the use of alternative-fuel combustion to provide kiln heat requirements, was evaluated. The resulting process heat-demand and CO2-emission computations were used as inputs in the LCA along with upstream literature data using a cradle-to-gate approach. LCA results focused on the most relevant environmental impact category of cement production, the Global Warming Potential (GWP (100)). The major findings showed a strong influence of process temperature and kaolin humidity on the lifecycle GWP, since both parameters affected not only the core-process heat demand but also the upstream impact related to fossil-fuel extraction, processing, transportation and distribution. Recirculating the exhaust provided a GWP reduction potential of up to 19%. In all examined production scenarios, metakaolin depicted a lower Global Warming Potential compared to clinker due to the avoidance of emissions related to limestone calcination. As regards the impact contribution of fuels, coal was responsible for higher onsite emissions and natural gas indicated higher upstream emissions. The GWP (100) could be further reduced when alternative waste fuels such as plastic waste, MSW (municipal solid waste) and tires were used. The LCA results have been cross-checked with previous literature reports, and the corresponding deviations are accordingly explained. In any case, the LCA results of different studies are rarely directly comparable due to the numerous assumptions required, which cannot be identically replicated.

Measuring systems in technologies of automated humidity control

This paper examines intelligent humidity sensors (transducers) as a component of an automated process control system that converts a controlled physical quantity into a measured signal for further processing in an automatic device, as well as mathematical models of intelligent support for bulk material moisture meters. It is demonstrated that one method for increasing the efficiency of the functioning of quality meters for various bulk materials is the development of conceptual foundations and their practical implementation in the construction of express devices capable of measuring grain and grain materials. The interaction of intelligent support measuring tools in technologies for automated moisture control in technological processes and control is investigated. The microwave method is recommended for monitoring the moisture content of grain and grain materials, as well as their metrological characteristics.

Effect of excitation parameters on screening performance of elastic screen surface with variable vibration intensity

In order to solve the problem of plugging and accumulation of moist material in the screening process, an elastic screen surface with variable vibration intensity was proposed in this paper. The kinematic characteristics of the elastic screen surface with variable vibration intensity were investigated by using acceleration sensors. The effects of excitation parameters on the screening performance during variable vibration intensity elastic screening were investigated by screening experiments. The results show that the acceleration of each measuring point of elastic screen surface has a linear relationship with screen body amplitude and a quadratic polynomial relationship with excitation frequency. Under different excitation parameters, the yield of each size fraction in undersize product and screen surface length all conform to the exponential relationship, and the relationship between screening efficiency and screen surface length all is exponential function. When the screen body amplitude is 3.10 mm and the excitation frequency is 15.84 Hz, the elastic screen surface with variable vibration intensity achieves the best screening performance, with the screening efficiency and total misplaced material content being 91.11% and 4.11% respectively.

An integrated approach to the monitoring of rising damp in historic brick masonry

Monitoring rising damp in historic masonry buildings requires an integrated approach, including not only the quantification of moisture in materials over time, but also the investigation of the supply of water from the ground, the evaporative capacity of the surrounding air, and the presence of potentially hygroscopic salts. However, this approach is seldom applied, hence our knowledge of the phenomenon of rising damp in real historic masonry structures is often only partial. In this paper, the proposed approach was applied to the church of Santa Croce in Ravenna, Italy, an outstanding example of masonry building affected by rising damp and related materials’ deterioration. Santa Croce is a Byzantine church surrounded by an archaeological site and the whole area is presently located under the water table level, requiring a continuously operating pumping system to prevent the flooding of the entire zone. The testing and monitoring of moisture and salts in the church’s materials started in September 2020 and is presently running. The data collected so far are presented and discussed in this paper, providing a contribution to a better understanding of this phenomenon. Moreover, during the monitoring period, a pumping system failure caused the flooding of the area in the period August-November 2021, allowing to investigate the impact of this event on the moisture in the materials. The protocol of testing described in this paper may provide a promising and effective method to investigate rising damp and is a starting point in view of its mitigation.

Dynamic identification of brick masonry semi-circular arches due to temperature and moisture

This paper presents the effects of changes in temperature and moisture content on the dynamic properties of semi-circular arches made of clay brick and gypsum mortar constructed and tested in the laboratory. First, the mechanical properties of the materials used were determined by experimental tests. Operational Modal Analysis was then performed for each condition to measure natural frequencies, mode shapes, and modal damping ratios. An empirical equation for estimating the natural frequencies of the studied arch at different material moisture contents was proposed using the obtained results from experimental tests. Finally, the Finite Element Model Updating Method (FEMU) was applied to calibrate some of the material mechanical properties in modelled arches. In contrast to the effect of moisture, temperature changes showed a difficulty to interpret effect on the dynamic properties of the arch. On the other hand, Poisson's ratio did not affect the dynamic behaviour of the specimen.

Investigation of NIR spectroscopy and electrical resistance-based approaches for moisture determination of logging residues and sweet sorghum

Techniques based on electrical resistance and near-infrared (NIR) spectroscopy were used to determine the moisture content (MC) of logging residues and sweet sorghum. The MC of biomass is a factor to be controlled that can affect the quality of final products. To accurately measure the moisture in fragmented materials, it is essential to increase the bulk density of the materials by compression. The low bulk density increased the error from the oven-drying MC and the variation between repeated measurements. The calculated correction factor made it possible to use a commercial wood moisture meter for biomass materials. Ordinary least squares regression models built with the electrical resistance data achieved coefficients of determination (R2) of 0.933 and 0.833 with root mean square errors (RMSE) of 0.505 and 0.891, respectively, for the MC predictions of logging residue and sweet sorghum. Partial least squares regression models combined with NIR spectroscopy achieved R2 of 0.942 and 0.958 with RMSE of 1.318 and 3.681 for logging residue and sweet sorghum, respectively. In contrast to the electrical resistance-based models, the NIR-based models could predict the MC regardless of the bulk density of the materials. Data transformation by the second derivative and removal of outliers contributed to the improvement of the prediction of the NIR-based models.

Study on the Mechanical Performance of Soft Sandy Soil Solidified by Epoxy Composites

In this work, we propose the stabilization of soft sea sand by an epoxy composite solidifier, which can be extremely beneficial in the fields of national defense, rescue engineering, and traffic emergency support under complex conditions. The effects of material ratio, curing time, curing temperature, and moisture content on the mechanical performance (compressive strength, bending strength, and splitting tensile strength) of solidified sea sand are investigated by indoor tests. The results indicate that the epoxy composite solidifier can rapidly enhance the mechanical performance of sea sand, thereby improving the beach trafficability and facilitating traffic emergency support. The strength of solidified sandy soil increases with the increase in curing time and temperature or with the decrease in moisture content. Furthermore, the epoxy composite solidifier exhibits good solidification capability under low temperatures and saturated moisture content. Keywords: epoxy resin; solidifier; sea sand; mechanical test

Moisture Determination for Fine-Sized Copper Ore by Computer Vision and Thermovision Methods.

The moisture of bulk material has a significant impact on the energetic efficiency of dry grinding, resultant particle size distribution and particle shape, and conditions of powder transport. This research aims to develop computer vision and thermovision techniques for the on-site estimation of moisture content in copper ore, for use, e.g., in dry grinding installations. The influence of particle size on the results of moisture estimation is also studied. The tested granular material was copper ore of particle size 0-2 mm and relative moisture content of 0.5-11%. Both vision and thermovision images were taken at standard and macro scales. The results suggest that median-intensity vision images monotonically reflect copper ore moisture in the range of about 0.5-5%. Suitable models were identified and cross-validated here. In contrary, thermograms should not be analyzed simply for their mean temperature but treated with computer vision processing algorithms.

Energetic and exergetic analysis of a biomass-fueled CCHP system integrated with proton exchange membrane fuel cell

As a high-efficiency and eco-friendly way of energy conversion, fuel cell has received much attention in recent years. A novel residential combined cooling, heating and power (CCHP) system, consisting of a biomass gasifier, a proton exchange membrane fuel cell (PEMFC) stack, an absorption chiller and auxiliary equipment, is proposed. Based on the established thermodynamic models, the effects of operating parameters, biomass materials type and moisture content on the system performance are closely investigated. Overall system performance is then compared under four different operating modes. From the viewpoints of energy utilization and CO2 emissions, the CCHP mode has the best performance with corresponding energy efficiency of 57.41% and CO2 emission index of 0.516 ton/MWh. Exergy analysis results suggest that the optimization and transformation on the gasifier and PEMFC stack should be encouraged. Energy and exergy assessments in this research provide pragmatic guidance to the performance improvement of the integrated CCHP systems with PEMFC. This research also achieves a reasonable combination of efficient cogeneration, green hydrogen production and full recovery of low grade waste heat.

A thermal conductivity model for insulation materials considering the effect of moisture in cold regions

Insulation is an important material for energy conservation and frost heave reduction in cold regions. The thermal conductivity of the insulation materials is usually considered as a constant. However, their thermal performance degenerates due to the absorption of water. To describe the variations of thermal conductivities with water content, a thermal conductivity model for three-phase insulation material was proposed by considering the insulation material's porous and moisture absorption characteristics. A tortuosity correction was introduced to reflect the heat conduction path. Then, the measured results and the existed models were used to evaluate availability of the proposed model. Finally, the quantitative influence of the porosity, water content, and thermal conductivity of solid phase on the thermal conductivity of wet insulation materials was analyzed. The results show that there is close agreement between the predicted results of the new model and the measured ones, with the maximum relative error <15%. The model with tortuosity correction can effectively calculate the thermal conductivities of the insulation materials in a full range of porosity (from 0 to 1). The thermal conductivity decreases with the increase of porosity, but increases with the increase of water content. The solid phase's thermal conductivity has little influence on the thermal conductivity of the insulation materials. The study can provide an effective method to predict the thermal performance variation of the insulation material due to the effect of moisture content in cold regions.

Reducing the thickness of the insulation layer of building walls based on the study of their temperature and moisture regime

The thickness of the building insulation is calculated with the table values of the moisture of building materials, which is included in the regulatory documents with a margin. The study proposes the method for determining the thickness of the insulation layer using the values of operational moisture. To determine the operational moisture of materials, the equation based on the moisture potential is applied, the solution of which is sought using a discrete-continuum approach. The proposed equation makes it possible to determine the distribution of the moisture potential function in the wall enclosing structure. Thereafter, using the moisture potential scale, the distribution of mass moisture over the thickness of the enclosure for the period of maximum moisture accumulation is determined. The equation for determining the thickness of the insulation layer, in which the calculated value of the operational moisture is explicitly substituted, is derived. An algorithm for calculating the thickness of the insulation layer, taking into account the unsteady-state heat and moisture regime of the building envelope, is given. The application of the proposed method on a wall enclosing structure with insulation from expanded polystyrene boards is illustrated. It was found that the thickness of the insulation can be reduced by 26 mm from 120 mm to 94 mm while maintaining the reduced heat transfer resistance of the building wall. It is noted that the proposed method can be applied in the design of new wall enclosing structures.

Local effects of printed logos and reflective striping fixed to firefighter clothing material packages under low radiation exposure.

Notifications that related 1st degree burns to reflective striping and impermeable clothing elements did reach the investigators, while the mechanisms behind this phenomenon are still unclear. Material tests for thermal and evaporative resistance, and for heat transmission under dry and wet conditions at low radiation levels were done to evaluate the performance of protective clothing with and without printed logos or reflective striping. The results under the specified conditions showed reduction of heat loss capacity under impermeable elements from dry to wet conditions. Reflective surfaces, even when more impermeable, showed still lower heat transmission through the textile package than materials without striping under tested moisture and radiation combinations. It can be expected that the reported 1st degree burns were related to clothing design and tightness/fit rather than to reflective striping. However, due to the fine balance between clothing thermal and evaporative resistance, outer material emissivity, moisture quantity and location in clothing and applied radiation level, a different setup could lead to different results.

Оптимизация процесса работы пресс-гранулятора соевой половы

To determine the optimal design parameters and modes of operation of the screw-type pelleting press, the authors studied the granulation of soybean chaff fractions pre-crushed to 5 mm with the addition of soybean grains as a binder. The pelleting process was stable at a temperature of the pelleting press barrel of 70…80°С and the temperature of pellets at the exit of 65 to 70°С. Humidity control was carried out in accordance with GOST 13496.3-92, the crumbling of pellets - in accordance with GOST 23513-79, GOST 22834-87. Fifteen experiments were carried out in three repetitions according to the matrix of the orthogonal central composition plan of the second order. The factors of the experiment included the matrix thickness, the moisture content of the raw material and the mass fraction of soybean grains in the raw material. The crumbling of the obtained pellets served as the optimization criterion. Based on the experiment results, an adequate regression equation was obtained. It was established that the smallest percentage of pellet crumbling is observed in the moisture content ranges of raw materials of 50 to 60% and the mass fraction of soybean grinding in raw materials of 15 to 16.5%. With a fi xed value of raw material moisture content, the optimal thickness of the pressing matrix corresponds to the range of 27.5 to 39.0 mm, while the mass fraction of soybean grain in the raw material is 15 to 25%. With a fi xed mass fraction of soybean grain, the optimal values of the pressing matrix thickness range between 30 and 40 mm, the values of the initial moisture content are 40 to 60%. To obtain pellets consisting of pre-crushed and moistened soybean chaff and soybean grains with the crumbling rate of less than 12%, the thickness of the matrix with holes with a diameter of 10 mm should be 30 to 40 mm, the mass fraction of soy in the raw material should correspond to 15 to 16.5%, and the moisture content of raw materials should equal 51 to 60%.

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.

Investigation of selected independent variables on extrusion of rice semolina with and without propeller

The influence of screws with and without propeller, as well as the independent variables of material moisture content, working screw speed, feeding screw speed and die temperature on the changes of some physical and mechanical properties during singles-screw extrusion of rice semolina was studied. The response surface methodology was used with an orthogonal central composite design. Optimum modes of operation which lead to the maximization of the mass flow rate and the sectional expansion index and the minimization of the specific mechanical energy were established. The obtained results show that the use of a propeller in single-screw extrusion leads to an increase in extruder mass flow rate, a decrease in the specific mechanical energy and an increase in the sectional expansion index.

Studying the Thermophysical Characteristics of the Muscle Mass of the Black Soldier Fly Larvaes (Hermetia Illucens) as a Drying Object

Introduction. The main component of the compound feedstuff is fish meal, which has unstable quality and high price. Fish and meat-and-bone meals are replaced with protein concentrates and higher quality larvae proteins. The source of feed protein is the biomass of the black soldier flies (Hermetia illucens), which have a rich amino acid composition and also process food waste. The aim of the work is to study the thermal-physical characteristics of the muscle mass of the black soldier fly larvaes (Hermetia illucens). Материалы и методы. The study focused on the muscle mass of black soldier fly larvaes (Hermetia illucens). The subject of the study is thermal-physical regularities during the drying process. The studies were conducted on the basis of Don State Technical University. The article describes determination of thermal-physical characteristics such as specific heat, thermal conductivity, moisture of the raw material, and oiliness. Results. Heat conductivity coefficient of water 0.555 W/(m∙K) for food and feed products from 0.25 to 0.40 W/(m∙K) black Soldier Fly larvae have a heat conductivity equal to 0.144 W/(m∙K), which is lower than conventional feedstuff components. The humidity of the examined raw material is 45% or higher while the heat conductivity remains linear and practically does not increase. Discussion and Conclusion. The results obtained during the work can be used for parameter determination and design of various types of dryers, and for mathematical description of the dynamics and kinetics of drying.

Correlation between relative humidity and the strength and deformation characteristics of unstabilised earth masonry

The mechanical properties of unstabilised earthen building materials are distinctively influenced by changes in material moisture content. However, this moisture-dependency often remains unconsidered in the calculation of the load-bearing capacity of earth constructions. This paper aims to derive a convenient way to sufficiently consider the impact of different material moisture contents on the mechanical properties of unstabilised earth masonry. Therefore, the influence of relative humidity and temperature on the strength and deformation characteristics of unstabilised earth blocks, earth mortar and earth masonry is evaluated by conducting compression tests under various climate conditions. The results show that the compressive strength and the modulus of elasticity are linearly correlated with the relative humidity, whereas changes in temperature at constant relative humidity have no significant influence. To account the distinct moisture-dependency, a general applicable modification factor for unstabilised earthen materials is provided, which enables the adjustment of the compressive strength and the modulus of elasticity in dependency of arbitrary hygroscopic material moisture contents.

Sustainable Coating Paperboard Packaging Material Based on Chitosan, Palmitic Acid, and Activated Carbon: Water Vapor and Fat Barrier Performance.

Synthetic polymer coatings impact the biodegradable behavior of cellulosic packaging material. The environmental consequences of food packaging disposal have increased consumer concern. The present study aimed to use natural polymer coatings incorporating palmitic acid and activated carbon applied to paperboard surfaces as a sustainable alternative to improve cellulosic packaging material's moisture and fat barrier properties, minimizing the environmental impact. The coating formulation was defined using a Factorial Experimental Design with independent variables: chitosan, palmitic acid, activated carbon concentrations, and the number of coating layers. The highest concentration of chitosan (2.0% w/w) filled the pores of the cellulosic paperboard network, supporting the compounds incorporated into the filmogenic matrix and improving the fat resistance. The water vapor permeability of the coated paperboard material (range: 101 ± 43 to 221 ± 13 g·d-1·m-2) was influenced by the hydrophobicity effect of palmitic acid, the non-polar characteristic of activated carbon, and the number of applied layers. The coating formulation selected was a chitosan concentration of 2.0% (w/w), a palmitic acid concentration of 1.8% (w/w), an activated carbon concentration of 1.2% (w/w), and an application of three layers. The coating provides the potential for a paperboard surface application, improving the cellulosic packaging material's fat and moisture barrier properties and maintaining biodegradability and recyclability.

Effect of Mat Moisture Content, Adhesive Amount and Press Time on the Performance of Particleboards Bonded with Fructose-Based Adhesives

The study evaluates the performance of laboratory, single-layered particleboards made out of fructose-hydroxymethylfurfural-bishexamethylenetriamine (SusB) adhesive as a sustainable alternative. Several production parameters such as mat moisture content (MMC), adhesive amount and press time were varied and their effect on the bonding efficiency investigated. The internal bond strength (IB) and thickness swelling after 24 h of water immersion (TS) were taken as evaluation criteria for the bonding efficiency. pMDI-bonded particleboards were produced as fossil-based, formaldehyde-free reference. Particleboard testing was complemented by tensile shear strength measurements and thermal analysis. It was found that the MMC has the highest impact on the internal bond strength of SusB-bonded particleboards. In the presence of water, the reaction enthalpy of the main curing reaction (occurring at 117.7 °C) drops from 371.9 J/mol to 270.5 J/mol, leading to side reactions. By reducing the MMC from 8.7%, the IB increases to 0.61 N/mm2, thus surpassing P2 requirements of the European standard EN312. At a press factor of 10 s/mm, SusB-bonded particleboards have a similar IB strength as pMDI-bonded ones, with 0.59 ± 0.12 N/mm2 compared to 0.59 ± 0.09 N/mm2. Further research on the improvement of the dimensional stabilization of SusB-bonded PBs is needed, as the TS ranges from 30-40%.

Performance analysis of cabinet type solar dryer for ginger drying with & without thermal energy storage material

Solar energy is one of the most pay-back sources of energy. Drying provides extended shelf life to agricultural crops in general and thus proper design of dryers will assist in drying them to an acceptable level and quality. This work has been carried out with the design & Development of the solar dryer novel design of the double air pass type collector. In this work fresh Ginger is used for complete drying to prepare the Ginger powder. Nowadays ginger powder is very useful in various medicines. In this research work, 2000gm fresh ginger has been selected for drying in a cabinet solar dryer. Thermal energy storage material with good latent heat was selected to improve the dryer performance. The initial moisture content in the fresh ginger is 80 % and after drying for 2 days without thermal energy storage material moisture available finally is 9 % & weight is 288 gm. A similar experiment was carried out for ginger Drying with thermal energy storage material in a solar dryer final moisture measured is 8 % & the weight measured is 251 gm. By doing the proper literature survey Atlas wax SF 42 material is selected as energy storage material. It’s a phase change kind of energy storage material. Having a melting point of 45 °C and Latent heat of 164 Kj. The efficiency of a solar Dryer without thermal energy storage materials is calculated 45 % and with thermal energy storage materials calculated 48 %. So the 3 % improvement is there in the efficiency of solar dryer by energy storage material with 2000gm quantity of Ginger. If the quantity is more with more capacity then efficiency can be increased beyond 3 %. The outcome shows that by using the thermal energy storage material efficiency of the dryer is improved as it has a higher moisture removal rate. The designed and developed solar dryer is cost-effective and the Payback period of the solar dryer is 14 months.