This study examines the influence of micro-particles derived from Urtica dioica L. (nettle) fibres on the mechanical behaviour of structural epoxy adhesive joints. Short-fibre filler (diameter < 100 & micro;m, length < 500 & micro;m) characterised by noticeable porosity and morphological heterogeneity was added to the epoxy matrix in various concentrations (0.25-1.00 wt.%). Static tests revealed that the optimum strength, deformability, and cohesion of the joints were achieved at 0.50 wt.%, resulting in up to a 20% increase in strength compared to the reference epoxy. Higher filler contents led to poorer dispersion, increased heterogeneity, and reduced mechanical properties. Under cyclic loading (low-cycle fatigue), joints with higher filler content exhibited significantly shorter fatigue life, with premature failure often occurring early in testing-joints with pure epoxy or with 0.25 wt.% filler demonstrated better stability and fatigue resistance. Scanning electron microscopy analysis confirmed delamination at both the adhesive-adherent interface and within the adhesive layer under cyclic stress, for components subjected to cyclic loading, pure epoxy or epoxy modified with up to 0.25 wt.% natural nettle filler appears to be the most effective solution. The findings highlight the potential of bio-based fillers to enhance sustainable structural adhesive system.

This study evaluated vacuum drying (VD) and infrared drying (IRD) methods for persimmon, including individual and two-step sequential processes (VD followed by IRD and vice versa). The combined drying strategies were selected to harness the rapid surface heating of IRD and the low-temperature, low-oxygen benefits of VD, aiming to overcome limitations of single drying methods such as extended drying times and nutrient degradation. Drying experiments were conducted using laboratory-scale equipment at 50-70°C, for VD, with a vacuum pressure of 50 mbar (absolute pressure) and a pump speed of 2 L/s. Results showed a significant effect of drying combination strategies on drying rate, duration, effective moisture diffusivity, shrinkage, activation energy, color characteristics, microstructure, and phytochemical constituents of persimmon. The shortest drying times were recorded for IRD (240 min), followed by VD + IRD (343 min) and IRD + VD (376 min), whereas VD required the longest (520 min). Effective moisture diffusivity ranged from 1.42 × 10-9 m2/s for VD at 50°C (VD-50) to 7.83 × 10-9 m2/s for IRD at 70°C (IRD-70), with both individual IRD-70 and a combination of IRD + VD demonstrating improved moisture transfer performance. The IRD + VD combination resulted in the best microstructure preservation and showed lower shrinkage compared to other drying strategies. Moreover, this combination best preserved the persimmon color with the lowest total color change (ΔE = 5.591), whereas VD showed the highest (ΔE = 35.875). Activation energy was lowest in IRD + VD (13.98 kJ/mol), followed by VD + IRD (18.61 kJ/mol), with higher values in VD (34.08 kJ/mol) and IRD (22.75 kJ/mol). Phytochemical analysis showed IRD (total phenolic content [TPC] = 35.79 mgGAE/g, total flavonoid content [TFC] = 54.83 mgQE/g) and IRD + VD (TPC = 17.02 mgGAE/g, TFC = 58.52 mgQE/g) retaining the highest bioactive compounds. This study contributes to optimizing drying techniques for persimmon, enhancing energy efficiency, preserving nutritional quality, and supporting sustainable food processing, making it relevant for the food industry, food engineering, and food science fields.

This study investigates the influence of various constructional parameters and weave structure on the differential shrinkage (DS) %, tensile strength, absorbency, drape, softness, smoothness and resilience properties of woven terry towels with the goal of optimizing these characteristics for better durability, aesthetic and functionality. This research explores how different variations in constructional parameters and weaves can affect performance of terry woven towels. The results demonstrate that weft density variation significantly influences both differential shrinkage (DS) % and other performance properties. It was concluded that increasing thread density of the towel resulted in lower absorbency, overall moisture management capacity (OMMC), drape, softness, and smoothness. However, the tensile strength, shrinkage, and resilience score increase with increasing thread density of the towel. The differential shrinkage % of the towel can be lowered using proper weave structure and reducing the difference of thread density of body and fancy portions in the towel. The findings also highlight that multi-response optimization can be used for optimization of multiple outcomes. Its implications are far-reaching, impacting efficiency, quality, and competitiveness across various industries. The ability to balance multiple objectives makes it a valuable tool for decision - makers aiming to achieve comprehensive and effective solutions. This research provides practical insights for selecting appropriate thread density and weave combination to achieve both aesthetic and functional comfort, offering valuable guidance for manufacturers aiming to produce woven terry towel on the loom with precise dimensional control and performance. The overall approach is a scientific solution to a complex industrial problem dealing with multiple complex and interrelated parameters especially in the production of high quality terry towels.

This research is focused on hybrid green composites using flax woven fabric in which the matrix phase was further reinforced with coconut shell waste-based cellulosic microparticles as fillers. Mesoscale mechanical models were successfully developed to simulate the tensile properties of such hybrid composites based on hybridization of fibers and biobased materials using epoxy resin. S-glass fabrics with plain, twill and biaxial constructions, were used as the outer layers, while plain-woven flax fabric was used as the middle layer. A high level of agreement was observed between the experimental and predicted values. The static tensile tests were followed by cyclic tensile tests, microscopic analysis of fracture surfaces and dynamic mechanical analysis. The influence of the hybrid fabric geometry and combination with biowaste-based micro cellulosic material was observed to significantly influence the tensile properties determined by both experimental and numerical analysis. Dynamic mechanical analysis also validated the quasistatic measurements. A higher storage modulus and loss modulus were registered for the hybrid composites impregnated with a 1 % bio filler-based matrix. The damping factor (tan delta) was lower for the hybrid composites than for the nonhybrid samples and the control samples from the pure matrix. This difference is attributed to the stronger interface between the fibers and the particle-based matrix, which restricts the molecular mobility and increases the stiffness of the composites. Fractographic images were obtained by scanning electron microscopy (SEM) to study the failure modes and mechanisms of the composite samples. The microparticles were uniformly dispersed in the epoxy resin and thus enabled microcracking rather than macrocracks. The failure mainly occurred due to fiber failure, matrix cracking and delamination. Such hybrid composites are useful for exterior and interior components in automotive applications.

The aim of this research was to evaluate the effect of untreated and 5% aqueous NaOH solution-treated filler of the plant Jatropha Curcas L. on the mechanical properties of adhesive bonds, especially in terms of their service life at different amplitudes of cyclic loading. As a result of the presence of phorbol ester, which is toxic, Jatropha oilseed cake cannot be used as livestock feed. The secondary aim was to find other possibilities for the utilization of natural waste materials. Another use is as a filler in polymer composites, that is, in composite adhesive layers. The cyclic loading of the adhesive bonds was carried out for 1000 cycles in two amplitudes, that is, 5–30% of the maximum force and 5–50% of the maximum force, which was obtained by the static tensile testing of the adhesive bonds with unmodified filler. The static tensile test showed an increase in the shear strength of the adhesive bonds with alkali-treated filler compared to the untreated filler by 3–41%. The cyclic test results did not show a statistically significant effect of the alkaline treatment of the filler surface on the service life of the adhesive bonds. Positive changes in the strain value between adhesive bonds with treated and untreated filler were demonstrated at cyclic stress amplitudes of 5–50%. SEM analysis showed the presence of interlayer defects in the layers of the tested materials, which are related to the oil-based filler used.

Vegetable oils represent an important element in protecting a sustainable environment. The pursuit of environmentally friendly solutions and the ever-increasing costs of synthetic oil production are increasing the interest in natural vegetable oils. This paper presents and discusses the possibilities of using the oils obtained from coconuts (Cocos nucifera L.) harvested in Indonesia (North Sumatra region), with three maturity levels (green, yellow, and brown), as lubricants. The specific mechanical energy for linear pressing of the green, yellow, and brown types was 22.3, 20.7, and 18.5 J·goil−1, respectively. The water content of the oils obtained from the green, yellow, and brown types was 1786, 2033, and 1902 mg H2O·g−1, respectively. The mathematical models for linear pressing were established. The sizes of the wear area for the green, yellow, and brown types were 25.7, 24.4, and 34.3 mm2, respectively. The UV–visible spectral curves of the oils, in the range of 180–320 nm, were determined. The results of the lubrication properties of the Reichert test showed that better lubrication properties were exhibited by the green and yellow types, which are comparable to the lubricating properties of engine oils. The results from the SEM images also showed a better structure of the worn surface and fewer traces of abrasive wear.

The research is focused on the evaluation of mechanical properties of adhesive bonds with a composite layer of adhesive to increase their service life (safety) under cyclic loading of different intensities. Cyclic loading represents a frequent cause of adhesive bond failure and, thus, a reduction in their service life. Waste from the production of coconut oil, that is, coconut shells in the form of particles, was used as a filler. Coconut shells are in most cases incinerated or otherwise uselessly incinerated, but they can also be used as a natural filler. Cyclic loading (quasi-static tests) was performed for 1000 cycles in two intensities, that is, 5–30% (157–940 N) of maximum force and 5–50% (157–1567 N) of maximum force. The results of the experiment showed a positive effect of the added filler, especially at an intensity of 5–50%, when the service life of adhesive bonds with a composite adhesive layer (AB10, AB20, AB30) increased compared to adhesive bonds without added AB0 filler, which did not withstand the given intensity. A more pronounced viscoelastic behavior of adhesive bonds was demonstrated at an intensity of 5–50% between the 1st and 1000th cycle. SEM analysis showed reduced wetting of the filler and matrix and delamination due to cyclic loading.

This study is focused on the mechanical properties and service life (safety) evaluation of hybrid adhesive bonds with shaped overlapping geometry (wavy-lap) and 100% natural cotton fabric used as reinforcement under cyclic loading using various intensities. Cyclic loading were implemented between 5–50% (267–2674 N) and 5–70% (267–3743 N) from the maximum strength (5347 N) measured by static tensile test. The adhesive bonds were loaded by 1000 cycles. The test results demonstrated a positive influence of the used reinforcement on the mechanical properties, especially during the cyclic loading. The adhesive bonds Tera-Flat withstood the cyclic load intensity from 5–70% (267–3743 N). The shaped overlapping geometry (wavy-lap bond) did not have any positive influence on the mechanical performance, and only the composite adhesive bonds Erik-WH1 and Tera-WH1 withstood the complete 1000 cycles with cyclic loading values between 5–50% (267–2674 N). The SEM analysis results demonstrated a positive influence on the fabric surface by treatment with 10% NaOH aqueous solution. The unwanted compounds (lignin) were removed. Furthermore, a good wettability has been demonstrated by the bonded matrix material. The SEM analysis also demonstrated micro-cracks formation, with subsequent delamination of the matrix/reinforcement interface caused by cyclic loading. The experimental research was conducted for the analysis of hybrid adhesive bonds using curved/wavy overlapping during both static and cyclic loading.

Optimizing the operating factors in edible oil extraction requires a statistical technique such as a response surface methodology for evaluating their effects on the responses. The examined input factors in this study were the diameter of pressing vessel, VD (60, 80, and 100 mm), temperature, TPR (40, 60, and 80 °C), and heating time, HTM (30, 60 and 90 min). The combination of these factors generated 17 experimental runs where the mass of oil, oil yield, oil extraction efficiency, and deformation energy were calculated. Based on the response surface regression analysis, the combination of the optimized factors was VD: 100 (+1) mm; TPR: 80 °C (+1) and HTM: 60 (0) min); VD: 60 (–1) mm; TPR: 80 °C (+1) and HTM: 75 (+0.5) min and VD: 100 (+1) mm; TPR: 80 °C (+1) and HTM: 90 (+1). The absorbance and transmittance values significantly (p < 0.05) correlated with the wavelength and temperature, but they did not correlate significantly (p > 0.05) with heating time. The peroxide value did not correlate significantly with temperature, however, it correlated significantly with heating time. Neither the acid value nor the free fatty acid value correlated with both temperature and heating time. The findings of the present study are part of our continuing research on oilseeds’ processing optimization parameters.

In the present study, a Box–Behnken design of response surface methodology (RSM) was employed to optimize the processing factors (force: 100, 150, and 200 kN; speed: 3, 5, and 7 mm/min; and temperature: 40, 60, and 80 °C) for extracting pumpkin seeds oil under uniaxial compression. The design generated 15 experiments including twelve combinations of factors and three replicates at the center point. The responses: oil yield (%), oil expression efficiency (%), and energy (J) were calculated, and the regression models determined were statistically analyzed and validated. The optimum factors combination: 200 kN, 4 mm/min and 80 °C predicted the oil yield of 20.48%, oil expression efficiency of 60.90%, and energy of 848.04 J. The relaxation time of 12 min at the optimum factors increased the oil efficiency to 64.53%. The lower oil point force was determined to be 57.32 kN for estimating the maximum oil output. The tangent curve and generalized Maxwell models adequately (R2 = 0.996) described the compression and relaxation processes of pumpkin seeds oil extraction. Peroxide value increased with temperatures. The study provides detailed information useful for processing different bulk oilseeds under uniaxial loading for optimizing the mechanical oil pressing in large-scale oil production.

This study examines the potential of applying computational intelligence modelling to describe the drying kinetics of persimmon fruit slices during vacuum drying (VD) and hot-air-drying (HAD) under different drying temperatures of 50 °C, 60 °C and 70 °C and samples thicknesses of 5 mm and 8 mm. Kinetic models were developed using selected thin layer models and computational intelligence methods including multi-layer feed-forward artificial neural network (ANN), support vector machine (SVM) and k-nearest neighbors (kNN). The statistical indicators of the coefficient of determination (R2) and root mean square error (RMSE) were used to evaluate the suitability of the models. The effective moisture diffusivity and activation energy varied between 1.417 × 10−9 m2/s and 1.925 × 10−8 m2/s and 34.1560 kJ/mol to 64.2895 kJ/mol, respectively. The thin-layer models illustrated that page and logarithmic model can adequately describe the drying kinetics of persimmon sliced samples with R2 values (>0.9900) and lowest RMSE (<0.0200). The ANN, SVM and kNN models showed R2 and RMSE values of 0.9994, 1.0000, 0.9327, 0.0124, 0.0004 and 0.1271, respectively. The validation results indicated good agreement between the predicted values obtained from the computational intelligence methods and the experimental moisture ratio data. Based on the study results, computational intelligence methods can reliably be used to describe the drying kinetics of persimmon fruit.

The present study examined the effects of heating and freezing pretreatments on the mechanical, chemical, and spectral characteristics of sunflower seeds and oil under a linear compression process involving a universal compression-testing machine and a pressing vessel of diameter 60 mm with a plunger. The heating temperatures ranged from 40 to 80 °C and freezing temperatures from −2 to −36 °C at constant heating time of 30 min. The pretreated samples of initial height of 80 mm (22.6 × 10−5 m3) were compressed under a preset load of 100 kN and a speed of 5 mm/min. The results showed that oil expression efficiency significantly increased (p < 0.05) with increased heating temperatures but decreased with freezing temperatures. The lowest energy per volume oil of 22.55 ± 0.919 kJ/L was recorded at 80 °C compared to 26.40 ± 0.307 kJ/L noticed at −2 °C and control (25 °C) of 33.93 ± 3.866 kJ/L. The linear regression equations expressing oil expression efficiency, energy per volume oil, peroxide value, and free fatty acid, dependent on heating and freezing temperatures, were described with coefficients of determination between 0.373 and 0.908. Increased heating temperatures increased the UV absorption rate of the oil samples at a wavelength of 350 nm. The study is part of the continuing research on linear compression modeling of all processing factors, whereby the results are intended to be applied to the non-linear process dealing with a mechanical screw press to improve the oil extraction process.

Viscoelastic behavior is an important parameter for the use of natural fibers in technical applications. Mathematical models to describe the relaxation and creep behavior of Ensete fibers were investigated. The aim of the experiment was to describe the short-term creep and relaxation behavior under tension loading. The fibers of Ensete ventricosum, originally from Ethiopian region Hawasa, were used in this experiment. Moisture content Mc = 8.54 ± 0.42% (d. b.) of the samples were determined. The viscoelastic tests were performed at six load levels (15, 30, 45, 60, 75, and 90% of yarn breaking load). Measured values of the relaxation and creep behavior were fitted to the mathematical models. The results show that generalized Maxwell model and Kelvin-Voight model with two branches can be used to describe relaxation and creep behavior of Ensete fibers.

The article examined the loading and unloading behaviour of bulk sesame seeds in relation to different forces between 1.5 and 4.5 kN and speeds between 1 and 10 mm.min(-1). The testing device (Labortech, MPTest 5.050, Germany) ofa maximum load of 5 kN was used for the compression test. The bulk sesame seeds sample was measured at an initial height of 40 mm using the vessel diameter of 60 mm with a plunger. Based on the compression test; the loading time of 737.150 +/- 15.127, 500 +/- 10.267 and 60.500 +/- 9.334 s was observed at speeds of 1, 5 and 10 mm.min(-1) and maximum force of 4.5 kN. Maximum deformation of 12.320 +/- 0.269 mm with a corresponding strain of 0.308 +/- 0.007 (-) and deformation energy of 25.495 +/- 0.191 J was observed at the lowest speed and maximum force. The applied forces at the various speeds did not initiate rupture of the bulk sesame seeds sample, hence there was no oil recovery. Using the multivariate analysis technique, the calculated parameters were statistically significant (p<0.05).

The present study is a follow-up of the previously published study on the mathematical description of loading curves and deformation energy of bulk oil palm kernels under compression loading, aimed at determining theoretically the amounts of force, pressure and energy along the screw lamella positions of the screw press FL 200 by applying the tangent curve mathematical model and the screwline geometry parameters (screw shaft diameter, screw inner and outer diameters, screw pitch diameter and the screw thickness). The fitting curve value of the tangent mathematical model was further examined at 2 and 3 by identifying the force, deformation, stress and compression coefficients at varying vessel diameters and initial pressing heights of the bulk oil palm kernels. Based on the results of the stepwise regression analysis, the amounts of the theoretical deformation energy in linear pressing as well as the theoretical force , pressure and energy of the screw press FL 200 were statistically significant (P-value < 0.05) or (F-value > significance F) in relation to the predictors ( , , and ). The coefficient of determination (R) values between 61 and 86% were observed for the determined regression models indicating that the responses , , and can accurately be predicted by the corresponding predictors. The normal probability plots of the responses approximately showed a normal distribution.

This study is focused on the utilization of image analysis for description of dimensions, and colours changes of fruits during drying process. Selected tropical fruits such are banana (Musa acuminata), mango (Magnifera indica) and pineapple (Ananas comosus) originally from North Sumatera in Indonesia were used in this experiment. Sliced pieces of the fruits were dried in experimental oven under temperature 90 °C for period of time 180 min and image of fruits samples were recorded by digital camera with HD resolution continuously throughout drying process. With aid of image analysis using Image J software and regarding to drying characteristics the colours and dimensions of the samples were analysed.

An intensive abrasive wear of agricultural machines and their parts occurs at the soil processing. An undesirable change of a tool surface occurs owing to the wear. Namely ploughshares of a plough are intensively abrasive worn. This undesirable change leads to a function loss. The paper deals with an evaluation of the ploughshare service life. The aim of the research was to evaluate the wear of the ploughshare with a layer of a carbide hardfacing OK Tubrodur 15.82 deposited on a bottom side of the ploughshare. The research was performed within a laboratory testing (a hardness HV30 and a wear) and field tests. Laboratory experiment results proved that the overlay material showed a significant increase of the wear resistance and the hardness. These conclusions of the laboratory testing were certified at the field tests. The research results certified this procedure as an efficient solution at the decreasing of the ploughshare wear at the ploughing.

The most important processes in food processing include drying. Generally it is the removal of water from the material for further processing or storage. This study was focused on the analysis of drying process of green coffee beans (Coffee arabica). The green beans, originally from Indonesia, were used in this experiment. Moisture content of beans Mc = 28.1 ± 1.7 % (w.b.) were determined. The beans were dried at different air temperatures Td = 40, 60, 80, 100 and 120 ± 1 °C. Drying tests were carried out on drying scales (Radwag, MA 50.R, Poland). The test was repeated three times for each temperature. Measured data were analysed by computer software Mathcad 14. Experimental drying curves at different temperatures were determined. The measured values of the drying curves of green coffee beans were fitted and a mathematical model was created. Model coefficients were determined and the proposed model was statistically analysed.

Three dimension virtual models of Avocado (Persea americana), Salak (Salacca zalacca), Dragon fruit (Hylocereus undatus), Mango (Mangifera indica), Coconut (Cocos nucifera) using 3D scanner Intel RealSense were determined. Calculated models based on arithmetic and geometric diameter were also determined. From statistically analysis implies that virtual models on significance level 0.05 are significantly different with calculated values based on arithmetic or geometric diameter.