Mechanics Research Articles

Optimal Control of a Harmonic Oscillator with Parametric Excitation

This paper addresses the time-optimal control problem for a harmonic oscillator characterized by a time-dependent frequency. The primary objective is to determine the minimal time required to transition the system from an initial state, defined by a given position and velocity, to a specified final state, while ensuring that the frequency remains within prescribed bounds. The key challenge lies in identifying the optimal switching times between two available frequencies to meet all boundary conditions efficiently. By examining various boundary scenarios, constructing the reachable set of all admissible trajectories, and employing both analytical techniques and control theory, we develop a robust solution strategy. This work holds particular relevance for practical applications demanding rapid state transitions, such as mechanical vibration control and signal processing, where achieving time-optimal performance is critical. Furthermore, the methods presented are adaptable to a wide range of systems facing similar constraints, providing a versatile and effective framework for time-optimal control.

Development of an Automotive-Relevant Recycling Process for Paper Fiber-Reinforced Polypropylene Composites

The automotive industry is under growing pressure from regulatory agencies to improve the recyclability of its plastic components. Simultaneously, manufacturers are adopting natural fiber composites in vehicles to reduce their carbon footprint and decrease reliance on petroleum-based materials. This presents a challenge at vehicle end-of-life, however, as natural fiber-reinforced polymers are substantially more difficult to recycle than their unreinforced counterparts. This study investigated the development of a mechanical recycling process for paper fiber-reinforced polypropylene composites, focusing on the impact of injection molding parameters—specifically, injection temperature and rate—on the thermal, mechanical, and water uptake properties of the composites. The results showed that processing temperature had a greater influence on composite performance than injection rate, with some limited interaction effects between the two. Higher processing intensity damaged the paper fibers, increasing the number of nucleation sites and resulting in greater polypropylene crystallinity. These structural changes reduced tensile properties at higher intensities, while flexural properties improved. Objective function analysis was applied to identify optimal processing conditions, balancing these competing trends. Overall, the findings demonstrate that paper fiber-reinforced polypropylene composites can be recycled into automotive-relevant injection molding compounds using conventional plastic manufacturing techniques, though careful tuning of processing parameters is essential to achieve optimal performance.

自走式多功能开沟施肥机的设计与实验

In orchard management, trenching operations are labor-intensive and have low efficiency, and mechanization is of crucial importance for the development of the fruit industry in China. In view of the many deficiencies of the existing chain-type and disc-type trenching machinery, this paper designs a self-propelled multifunctional orchard trenching machine. Its core component, the double-disc trenching disc, is an innovative design. Compared with the traditional single-disc trenching disc, it effectively reduces the trenching power consumption while ensuring the trenching depth and width, and significantly improves the operation efficiency. The trenching machine is composed of a frame, a gearbox, a double-disc trenching disc, a trenching knife, a soil retaining plate, etc. Field tests show that the operation speed reaches 1.2 kilometers per hour, the trenching depth is 31.2 cm, the width is 30.5 cm, and the stability coefficient of the trenching depth is 97.2%. Its power consumption is in a relatively good parameter group. When the cutter roller speed is 400 r/min, the forward speed is 0.8 km/s, and the trenching depth is 0.3 m, the average power consumption value of the trenching component is measured to be approximately 7.63 kW, with an 11.18% reduction in power consumption compared with the current trenching machines. And it meets the requirements of orchard agronomy and industry standards. In terms of improving productivity, its high-efficiency operation performance can greatly shorten the trenching operation time in the orchard, enabling fruit growers to arrange production more reasonably and increase fruit output. In reducing labor costs, mechanization replaces manpower, reduces manpower input, reduces labor cost expenditures, and at the same time avoids the instability of manpower operations. For the sustainability of orchard operations, the precise and stable trenching operation helps to optimize the utilization of land resources, ensure the quality of orchard agronomy, maintain the long-term production capacity of the orchard, promote the sustainable development of the orchard, and inject new impetus into the mechanization process of the fruit industry.

THE EFFECT OF ANIONIC OIL ON THE SOFTENING PROCESS OF OLD STOCK UPHOLSTERY LEATHER USING PADDING METHOD

Location and mechanism of leather storage that is not ideal can cause changes in the character of the old stock leather. One of the effects that is often found when storing finished leather is reducing skin softness. The conventional method of increasing leather softness of old stock is through a mechanical staking process. Staking will only be effective in softening the leather if the leather has enough oil content, if it doesn't have enough oil content it will potentially cause cracks in the grain. In this study, control leather (K) was only given mechanical treatment. Meanwhile, for treatment leather (T), the mechanical process is carried out before and after adding mayonnaise oil using a rubbing method on the flesh to maximize the oil lubrication effect on old stock leather. The use of anionic oil, mayonnaise oil, which is applied to the flesh of the skin using the wiping method on T skin, produces a higher difference in the increase in softness, namely 0.5 mm, when compared to K leather which only undergoes a mechanical process (staking and toggling), namely 0.3 mm. This shows that the addition of mayonnaise oil and emulsifier to the flesh is able to re-lubricate the leather fibers thereby increasing skin laxity.

THE MATHEMATICAL MODELS OF ELECTROCHEMICAL GRINDING FOR THE PRECISION PRODUCTION

This article considers the development of a mathematical model of electrochemical grinding for processing precision components operating at varying loads. The combination of processes (for example, the mechanical and electrochemical material removal processes) significantly improves operation control capabilities by increasing the number of control inputs and selected input variables. The results of the research are presented as evaluated based on the capacity of products manufactured using this grinding method. The conducted qualitative and quantitative assessments demonstrate the adequacy of mathematical models. The difference between experimental and calculated values made up 5-10%. The electrochemical grinding helps improve the operability of components operating at varying loads compared to mechanical grinding.

Оценка качества и механических свойств получаемых слоев металла из низкоуглеродистой стали методом WAAM с использованием дополнительной механической и ультразвуковой обработки

Introduction. Additive manufacturing is a technology that enables three-dimensional (3D) components to be printed layer by layer according to digital models. Completely different from traditional manufacturing methods such as casting, forging, and machining, additive manufacturing is a near net shape manufacturing process that can greatly enhance design freedom and reduce manufacturing runtime. The material processing challenges in Wire and Arc Additive Manufacturing (WAAM) are related to achieving performance metrics related to geometric, physical, and material properties. Tight tolerances and stringent surface integrity requirements cannot be achieved by utilizing stand-alone AM technologies. Therefore, WAAM parts typically require some post-processing to meet requirements related to surface finish, dimensional tolerances and mechanical properties. It is therefore not surprising that the integration of AM with post-processing technologies into single and multi-setup machining solutions, commonly referred to as hybrid AM, has become a very attractive proposition for industry. The purpose of the work is to evaluate the quality and mechanical properties of the resulting metal layers of mild steel by WAAM method using additional mechanical and ultrasonic processing. Research Methods. To conduct the experiments, a set of welding equipment was used — a single-phase inverter device KEMPPI Kempomat 1701, designed for welding with wire in shielding gases. A mixture of argon and carbon dioxide (80 % argon and 20 % CO2) was used as a shielding gas. SV-08G2S (0.8 C-2 Mg-Si) wire was used as the surfacing material. A plate made of steel St3 with overall dimensions 150×100×5 mm was used as a base for surfacing. The surface of the plate before surfacing was thoroughly cleaned from the layer of oxides, oil, rust and other contaminants. For this purpose mechanical cleaning of the surface was used with BOSCH abrasive wheel with a diameter of 125 mm diameter and a grit size of 120. Before surfacing the surface of the product was degreased with white spirit. The gas flow rate was set at 8 dm3/min. To select the optimal wire feed rate and volt-ampere characteristic, surfacing was performed at each adjustment step of wire feed rate, and voltage. Mechanical statistical tensile tests, chemical composition analysis and metallographic studies were also performed. Results and Discussion. Gas porosity is a typical defect that occurs during the WAAM process and should be eliminated because it adversely affects the mechanical properties. Initially, gas porosity leads to a reduction in the mechanical strength of the part due to damage from microcrack formation. In addition, it often causes the surfaced layer to have worse fatigue properties due to the spatial distribution of different shape and size structures. In our experiments we found that a wire feed speed range of 5–6 m/min is optimal. Increasing the flow rate of shielding gas in the range of 8–14 l/min allows reducing porosity in the surfaced metal to almost zero. The mechanical properties of the surfaced beads show that the average value of yield strength after machining is higher than that of unprocessed specimens. The data obtained from these experiments are in good agreement with those reported in the literature. The presented results can be used in real WAAM technological processes.

Investigating the effect of an inclined magnetic fieldon heat and mass transmission in turbulent squeeze flowof UCM fluid between parallel plates

This paper investigates the effects of an inclined magnetic field on heat and mass transfer in turbulent squeeze flow of a viscoelastic fluid with an upper-convected Maxwell model. Squeezing flow is an important phenomenon in various industrial and mechanical processes related to flows between parallel surfaces. Mathematical modelling for the law of conservation of mass, momentum, heat and concentration of nanoparticles is executed. The study employs a system of partial differential equations to describe the flow issue. Governing nonlinear partial equations are reduced into nonlinear ordinary differential equations. The modelled equations are then solved numerically by utilizing the efficient Adams-Moulton method of the fourth order based on the shooting technique using the Fortran programming language. Numerical results are compared with another numerical approach and an excellent agreement is observed. The effects of various factors on the non-dimensional velocity, temperature, and concentration patterns are presented using graphs, while tables are used to assess the numerical values of the skin friction, Nusselt and Sherwood numbers. It is found that the temperature profile decreases as the compression parameter increases but increases with an increase in the Eckert number. The results of this study could be useful in designing heat and mass transfer equipment for applications in viscoelastic fluid flows under an inclined magnetic field.

Apparent specific surface area as an indicator of the degree of cellulose microfibrillation

AbstractTracking mechanical microfibrillation in nanocellulose production is time-consuming due to a lack of quick characterization methods. This study investigates optical monitoring of the mechanical microfibrillation process by determining the dimensions of microfibrillated cellulose (MFC) particles on micron scale. Bleached hardwood pulp was microfibrillated using three sets of grinding discs in a six-stage pilot process, analyzing MFC characteristics as a function of specific energy consumption via image analysis. A laboratory-scale ultrafine grinder was also used for comparison. The degree of microfibrillation was assessed over a broad energy range using the equivalent diameter derived from the MFC length and width through image processing. The microfibrillation process adhered to Rittinger’s law, i.e., changes in the apparent specific surface area (SSA) were linearly proportional to the applied grinding energy. SSA, being inversely proportional to equivalent diameter, predicted MFC quality in terms of nanofilm strength properties. The optical fiber image analyzer proved suitable for online monitoring and control of microfibrillation processes. Despite resolution limits in detecting sub-micron particles, their proportion interrelates to the size of optically visible particles, covering industrial needs for mechanical microfibrillation.

THE ESSENCE OF THE PROCESS OF VIBRATIONAL FINISHING AND CLEANING, ITS TECHNOLOGICAL CAPABILITIES AND WAYS TO INCREASE EFFICIENCY

The main provisions of the classification of the vibration processing process depending on the characteristics and composition of the processing medium are given. It is established that vibration processing is a mechanochemical removal of metal particles and its oxides, and plastic deformation of the microroughness of the surface of the part. It was found that vibration processing is related to mechanical dynamic processes, when using chemically active solutions it is related to mechanochemical processes, according to technological purpose to dimensionless processes, according to the type of tool – to processing with free abrasives. It was determined that vibration processing is characterized by the dynamic mechanochemical effect of abrasive medium granules on the treated surface and the acoustic effect of shock waves. It has been established that the features of mechanical and physicochemical phenomena of vibration processing differ in the physical properties of the granules of the medium, the characteristics of the material of the processed parts, the dynamic nature of the process, the composition and properties of the chemically active solution. A classification of defects in the formation of parts, controlled parameters and vibration processing operations is given. The technological capabilities of the processing are presented, these are micro-cutting and surface plastic deformation, the effect of variable accelerations and continuous application of micro-impacts to the surface being processed, which ensures the dynamic nature of the process and creates conditions for strengthening and stabilizing processing. The design of the vibration machines allows the use of various compositions of solid, liquid and mixed compositions of working media. To increase the efficiency of the process, a variable scheme for combining technical solutions of new varieties of the vibration processing process is proposed. It has been established that by combining various combinations of technological and design parameters it is possible to expand the scope of application of the vibration finishing and cleaning process based on the creation and implementation of its varieties.

Quality prediction and process optimization in abrasive waterjet cutting of ultra‐thick carbon fiber reinforced polymer

AbstractSurface roughness and delamination extent are key indicators for assessing the surface quality of machined carbon fiber reinforced polymer (CFRP) laminates. This study conducted an in‐depth investigation on the uncontrollable surface quality of abrasive water jet (AWJ) machining of ultra‐thick CFRP. Considering the sensitivity of the laminate structure to the jet impact angle, an optimized response surface methodology was used to analyze the effects of process parameters on surface roughness. Additionally, the differences in surface roughness on both sides of the kerf under non‐orthogonal cutting were examined. Based on these analyses, a surface roughness prediction model was developed. Furthermore, the study comprehensively analyzed the effects of material mechanical properties and process parameters on delamination damage. Using dimensional analysis, a predictive model for the maximum delamination length, considering jet energy dissipation, was established. The novelty of this research is to reveal the difference in surface quality on both sides of the kerf under non‐orthogonal cutting, and to establish prediction models for surface roughness and delamination damage based on the energy dissipation characteristics of ultra‐thick CFRP AWJ machining. This research provides essential modeling foundations for enhancing the controllability of AWJ machining quality for ultra‐thick CFRP complex components.Highlights Surface roughness and delamination damage impact AWJ use for ultra‐thick CFRP. Non‐orthogonal cutting causes surface quality differences on kerf sides. A model for kerf surface roughness at any jet impact angle was established. The delamination mechanism in internal path cutting was analyzed. The delamination length model for ultra‐thick CFRP laminates was established.

Influence of the mechanical activation process on the corrosion of Ti2⁠AlN MAX phase obtained by hot pressing

The Ti2AlN MAX phase is known for its unique blend of metallic and ceramic properties, including high electrical and thermal conductivity and excellent oxidation and corrosion resistance. This study focuses on the influence of the mechanical activation process on the electrochemical properties of Ti2AlN in a saline environment. High-purity powders of AlN and Ti were mechanically activated or mixed and sintered to synthesize the Ti2AlN MAX phase. The electrochemical behavior was assessed through potentiodynamic curves and electrochemical impedance spectroscopy, while surface characteristics were analyzed using SEM-EDS and XPS post-exposure to a 3.5% NaCl solution. Results reveal that Ti2AlN forms protective Al2O3 and TiO2 layers, enhancing its corrosion resistance. Mechanically activated samples (MAP) displayed different corrosion behavior than non-activated samples (NMAP), with MAP showing reduced corrosion resistance. This discrepancy is attributed to differences in oxide formation and microstructural changes due to mechanical activation. This research not only elucidates the corrosion mechanisms of MAX phases in chloride-rich environments but also analyzes the effect of mechanical processing on their properties, contributing to developing Ti2AlN applications where high durability and resistance are critical.

Anisotropy of non-Darcian flow in rock fractures subjected to cyclic shearing

Non-Darcian flow in rock fractures exhibits significant anisotropic characteristics, which can be affected by mechanical processes, such as cyclic shearing. Understanding the evolution of anisotropic non-Darcian flow is crucial for characterizing groundwater flow and mass/heat transport in fractured rock masses. In this study, we conducted experiments on non-Darcian flow in single rough fractures under cyclic shearing conditions, aiming to analyze the anisotropic evolution of inertial permeability and viscous permeability. We established quantitative characterization models for the two types of permeability. First, we conducted cyclic shearing experiments on four sets of 24 rough rock fractures, investigating their shear characteristics. Then, we performed 480 non-Darcian flow experiments to analyze the anisotropic evolution of viscous permeability and inertial permeability of these rock fractures. The results showed that viscous permeability exhibited significant differences only in the orthogonal direction, while inertial permeability exhibited differences in both orthogonal and opposite directions. With increase in the shear cycles, the differences in the orthogonal direction gradually increased, while those in opposite direction gradually decreased. Finally, we established characterization equations for the two permeabilities based on the proposed directional geometric parameters and validated the performance of these equations with experimental data. These findings are useful for the quantitative characterization of the evolution of non-Darcian flow in fractures under dynamic loading conditions.

Ore-forming processes of giant carbonate-hosted Zn Pb deposit and Ge enrichment mechanism in Zhugongtang, Guizhou Province, China: Constraints from trace element and isotopic compositions of sulfides

Ore-forming processes of giant carbonate-hosted Zn Pb deposit and Ge enrichment mechanism in Zhugongtang, Guizhou Province, China: Constraints from trace element and isotopic compositions of sulfides

Effect of theoretical volume fraction (TVF) of reinforcements on Al5083/SiC and Al5083/ZrB2 surface composites produced by friction stir processing

This study focuses on the effects of theoretical volume fraction (TVF) on the microstructure and mechanical properties of silicon carbide (SiC) and zirconium diboride (ZrB2) ceramic reinforced Al5083 surface composites (SC). Al5083-H111 was used as the base material (BM), SiC and ZrB2 were used as reinforcement materials, and TVFs were determined as 5, 10, 15, and 20% for SCs produced by the friction stirring process (FSP). Macrostructure, microstructure, X-ray diffraction (XRD) analysis and mechanical properties such as microhardness, tensile strength (UTS), and wear behaviour were characterised. When the TVF and AVF values of SiC and ZrB2 particles were compared, it was found that the AVFs were lower than the TVFs. Significant decreases in the changes in the SZ areas of SiC and ZrB2 particle SCs were detected depending on the reinforcement size. In the time-dependent axial load graphs of SiC and ZrB2 reinforced samples, load values ranging from 7800 to 8200 N were obtained and it was determined that these values were sufficient for friction heat, hydrostatic pressure, and plasticization in FSP. As a result of mechanical characterisation processes, the microhardness values and wear rates of ZrB2 reinforced SCs in the stir zone (SZ) were higher than SiC reinforced SCs. When the reinforcement particles were compared, it was observed that ZrB2 reinforced SCs exhibited higher microhardness and wear resistance than SiC reinforced SCs. As a result of all tests and investigations, it was determined that the ideal TVFs were 15% for SiC reinforced SCs and 5% for ZrB2 reinforced SCs. The microhardness value of ZrB2 reinforced SC with 20% TVF was 119.6 HV, while the UTS and volume loss values of ZrB2 reinforced SC with 5% TVF were found to be the highest values with 305.86 MPa and 1.83 mm3, respectively. Compared to BM, these values showed significant improvements in mechanical test results, especially in wear behavior. The results obtained showed an improvement of 55% in microhardness, 3.3% in UTS values, and 309% in wear behavior.

Rupture Mechanics of Blood Clot Fibrin Fibers: A Coarse-Grained Model Study

Thrombosis, when occurring undesirably, disrupts normal blood flow and poses significant medical challenges. As the skeleton of blood clots, fibrin fibers play a vital role in the formation and fragmentation of blood clots. Thus, studying the deformation and fracture characteristics of fibrin fiber networks is the key factor to solve a series of health problems caused by thrombosis. This study employs a coarse-grained model of fibrin fibers to investigate the rupture dynamics of fibrin fiber networks. We propose a new method for generating biomimetic fibrin fiber networks to simulate their spatial geometry in blood clots. We examine the mechanical characteristics and rupture behaviors of fibrin fiber networks under various conditions, including fiber junction density, fiber tortuosity, fiber strength, and the strain limit of single fiber rupture in both tension and simple shear cases. Our findings indicate that the stress-strain relationship of the fibrin fiber network follows a similar pattern to that of individual fibers, characterized by a shortened entropy stretching phase and an extended transition phase. Fiber junction density, fiber strength, and single fiber rupture limit predominantly influence the stress of the network, while fiber tortuosity governs the strain behavior. The availability of more fibers in shear cases to bear the load results in delayed rupture compared to tension cases. With consideration of different factors of fibrin fibers in networks, this work provides a more realistic description of the mechanical deformation process in fibrin fiber networks, offering new insights into their rupture and failure mechanisms. These findings could inspire novel approaches and methodologies for understanding the fracture of fibrin networks during a surgical thrombectomy.

The influence of external action on the dynamics of elastic, thermal and concentration waves propagation

This paper presents the nonlinear coupled mathematical model allowing investigating the interrelation between the mechanical, thermal and diffusion processes in solid body. The model takes into account the finiteness of relaxation times of mass and heat fluxes. This is of interest for dynamical processes with characteristic times comparable to relaxation times, when the changes in the temperature and impurity concentration are described by hyperbolic thermal conductivity and diffusion equations. Additionally, the model takes into account the temperature and concentration dependencies of the diffusion coefficients; it gives rise to additional nonlinearity. The model is thermodynamically consistent and follows from the nonlinear equations of the thermoelastic diffusion theory. The implicit difference scheme of second approximation order in time and spatial steps, linearization relatively to known time moment and double-sweep method are used for the numerical implementation of the equation system. Examples of interrelating wave propagating under external actions are considered. The results show that distortions in the strain/stress and temperature distributions appear due to the interaction between the phenomena of different physical nature. The specific rates of different physical processes are different. Although diffusion is the slowest of them all, the influence of the diffusion wave is reflected in stress and strain waves far beyond the diffusion wave front. It is shown that regardless of the external action character and impulse form, the influence of the considered processes on each other does not change, but the wave picture becomes much more complicated with increasing number of actions.

Substantive innovation or strategic catering: Capital market pressure and corporate green innovation structure

Green innovation requires a market environment willing to take on more risk and accept failure. Capital markets are essential in green innovation because they can spread out the risks associated with innovation. Compared to existing research, this paper focuses on the impact and processes of the short-selling mechanism on corporate green technology innovation structure. Specifically, this study utilizes a difference-in-difference model to examine the effects and underlying mechanisms based on the listed firms from 2011 to 2022. The results suggest that the pressure from the capital market might encourage the development of green technological innovation in corporations. Still, it also hinders the establishment of a structure for corporate green innovation and fosters the expansion of strategic patent behavior. The influence is achieved through enhancing managerial performance, monitoring external pressures, and transmitting stock price information. Heterogeneous analysis confirms that independent directors ratio and CEO duality play a critical role. The findings demonstrate how capital market pressure can affect corporate green innovation structure, support the critical role of capital market and contribute to further engagement in corporate green technology innovation.

3D printing of biomimetic hierarchical surface textures using L-PBF for improving tribological performance of Ti6Al4V alloy

Energy and material losses due to friction and wear during the use of materials bring about very serious costs in every sector. In order to minimize friction and wear losses of materials, different surface engineering applications are used, especially surface coatings, thermal, mechanical and thermochemical processes. On the other hand, it has been shown in recent years that the tribological properties of materials can be controlled by creating different types of biomimetic hierarchical patterns on the surface of materials. Therefore, this study investigates both the individual and the synergetic effects of both biomimetic surface textures and thermal oxidation process on the tribological performance of Ti6Al4 V alloy. For this purpose, hierarchical models were produced using the laser powder bed fusion (L-PBF) technique, which is one of the additive manufacturing methods. Snake skin, shark skin and tree frog models were used as biomimetic hierarchical models. Additionally, flat and random snake skin models were used to examine the effect of texture orientation. Moreover, thermal oxidation was carried out at 700 ⁰C for 2 h and 4 h and the wear tests were carried out using a reciprocation-type tribo-tester under dry and simulated body fluid (SBF) conditions. As the oxidation time increased, the hardness and surface roughness of the material increased. A significant improvement in the wear rate of biomimetic models was observed compared to the non-textured sample. Lower tribological performance was observed in the tree frog model (hexagonal geometry) compared to other biomimetic models due to the presence of sharp corners. In particular, the snakeskin model provided the best wear rate because it trapped wear residue and provided additional hydrodynamic pressure. The highest tribological performances for all samples were observed in the samples oxidized at 700 ⁰C for 4h.

Chemo-mechanical benchmark for phase-field approaches

Abstract Phase-field approaches have gained increasing popularity as a consequence of their ability to model complex coupled multi-physical problems. The efficient modeling of migrating diffuse phase boundaries is a fundamental characteristic. A notable advantage of phase-field methods is their ability to account for diverse physical driving forces for interfacial motion due to diffusive, mechanical, electro-chemical, and other processes. As a result of this versatility, phase-field methods are frequently employed in the fields of materials science, mechanics, and physics, and are continually undergoing development. To test the accuracy of these developments, it is indispensable to establish standardized benchmark tests, to ensure the thermodynamic consistency of studies carried out. This work presents a series of such tests based on chemo-elastic equilibrium states for Fe-C binary alloys, benchmarking the performance of a phase-field model with chemo-elastic coupling based on the grand potential density. Use of parameters for the Fe-C system from a Calphad database allows for the determination of the Gibbs free energy, thereby enabling the quantification of chemical driving forces. For a circular inclusion, the capillary driving force is derived on a geometrically motivated basis using the lever rule and expressed as a function of the chemical potential. These simulations contribute to the development of standardized benchmark tests that validate chemical, capillary, and mechanical driving forces separately and in combination. The present study compares phase-field simulation results with results from the analytic solution of chemo-elastic boundary value problems and the generalized Gibbs–Thomson equation.

Influence of physical forms of non-forage diet on growth performance, feeding behavior, rumen and blood indices, and nutrient digestibility in fattening goats

The aim of this study was to evaluate the effects of physical forms (PF) of a non-forage fiber-based fattening diet on the growth performance, feeding behavior, nutrient digestibility, blood, and rumen indices in male Beetal goats. Thirty male goats with an average body weight (BW) of 32 ± 1 kg were assigned to one of three dietary treatments in a randomized complete block design. The treatments were as follows: (1) Pelleted (P) diet, where all ingredients were ground to 2 mm and then pelleted; (2) Texturized (TX) diet, where all ingredients, except whole corn grain, were ground to 2 mm, pelleted, and then mixed with whole corn grains; and (3) Unprocessed conventional mix (UCM), where all ingredients were mixed without any mechanical processing. The experimental duration was 12-week, two weeks for dietary adaptation, nine weeks for growth data collection, and one week for evaluation of nutrients digestibility. Daily dry matter intake (DMI) and DMI as a percentage of BW were higher (P < 0.05) in the P diet compared to the TX diet. The male goats fed with the UCM exhibited higher (P < 0.05) average daily gain and gain-to-feed ratio than TX and P diet. The ruminal pH tended to be higher (P < 0.05) in the goats fed the UCM compared to those fed the TX and P diets. The odds of having a fecal consistency score of 3 or more were 16.4 times (2.18–123.97) greater in the P diet and 9.1 times (1.15–72.16) in the TX diet than in the UCM. The intake of DM, NDF, feeding and total rumination time, were higher (P < 0.05) in goats fed UCM than those fed P and TX diets. The digestibility of NDF and EE were higher (P < 0.05) in the UCM and TX than in the P diet. These findings suggest that incorporating an unprocessed diet composed of whole corn grain and soyhulls can lead to enhanced growth performance, improved feeding behavior, and better nutrient utilization.