Mechanical Processing Methods Research Articles

Mechanical Processing with Solid-State of Supercapacitor Materials: A Review of High Energy Milling and High Velocity Particle Methods

Supercapacitors have emerged as a crucial energy storage technology, bridging the gap between traditional capacitors and batteries. The performance of supercapacitors is heavily dependent on the properties of the electrode materials used. Mechanical processing methods, particularly High Energy Milling (HEM) and High-Velocity Particle (HVP) methods have shown great promise in enhancing the physical and electrochemical properties of supercapacitor materials. This review explores the fundamental principles, mechanisms, and recent advancements in HEM and HVP techniques for the synthesis and modification of supercapacitor materials. High energy milling, including ballmill and attritor milling, facilitates particle size reduction, increased surface area, and the creation of nanostructures, leading to improved capacitance and energy density. High velocity particle methods, such as cold spraying and thermal spraying, enable the deposition of uniform and dense coatings, enhancing conductivity and stability. The review also discusses the impact of process parameters on material properties, the challenges faced in scaling up these techniques, and the potential future directions for research. By providing a comprehensive overview of these mechanical processing methods, this paper aims to highlight their significance and potential in advancing supercapacitor technology.

The use of precious metals in restorative dentistry

This review delves into the historical and contemporary use of precious metals in restorative dentistry, tracing the evolution from ancient practices to modern technological advancements. It underscores the critical role of metallic materials, such as gold, silver, copper, and alloys like cobalt-chromium and titanium, in dental restorations due to their superior mechanical properties, including high elastic modulus, tensile strength, and hardness. These materials are favored for their biocompatibility, corrosion resistance, and adaptability to various manufacturing processes, including casting, mechanical processing, and advanced methods like CAD/CAM, laser sintering, and welding. Despite the advent of alternative materials catering to aesthetic preferences, metals maintain their relevance in dentistry for structural components in prosthetics, demonstrating significant advancements in dental material technology. The review highlights the importance of understanding the properties and behaviors of these materials within the oral cavity to ensure the quality and durability of dental restorations. Through a comprehensive literature search and analysis of metallurgy, manufacturing, and classification, this paper presents a thorough exploration of the indispensable role of precious metals in enhancing dental health and restorative practices.

Full-Fat Soybean Meals as an Alternative Poultry Feed Ingredient-Feed Processing Methods and Utilization-Review and Perspective.

On a global scale, the poultry industry expands its wings in terms of meat and egg production to the masses. However, this industry itself requires a sustainable and permanent supply of different inputs, one of which is poultry feed and nutrition. Soybean is a versatile protein that is offered to poultry in different inclusion rates in commercial diets after being processed using various thermal and mechanical processing methods. Conventional commercial soybean meal is usually prepared by the extraction of oil from whole soybeans using solvents, producing a meal that has approximately 1% crude fat. Without oil extraction, full-fat soybean (FFSBM) is produced, and it is an excellent source of dietary energy and protein for poultry with a nutritional profile of 38-40% protein and 18-20% crude fat, on average. FFSBM has less crude protein (CP) than solvent-extracted soybean meal (SE SBM) but higher metabolizable energy due to higher fat content. Alternatively, extruded expeller processing produces defatted soybean meal containing approximately 6-7% crude fat. Studies have demonstrated that FFSBM can be used in poultry diets to improve poultry nutrition, performance, and quality of the poultry meat and eggs produced. This review aims to evaluate the nutrition and use of meals prepared from conventional and high-oleic soybeans using various feed processing methods.

Improved Artificial Aggregates for Use in Green Roof Design

The development of surfaces in cities, as a result of progressive urbanization, not only reduces the natural retention capacity of the environment but also causes changes in the water balance. In urbanized areas, the amount and intensity of rainwater discharged to receivers increase, and the time of water outflow from the catchment area shortens. Low retention does not provide effective responses to the local water deficit and does not limit the effects of excess water during flood periods. Furthermore, aging drainage systems do not always have the required hydraulic efficiency in absorbing runoff after intense and heavy rainfall or snowmelt. The aim of the work was to determine the possibility of obtaining flat aggregates with a grain size of 2–16 mm from clay-silt fractions from sedimentation tanks using selected mechanical processing methods (crushing and screening in a crusher-screener system with recycling). An important issue was the examination of the physical and mechanical properties of the produced aggregates after firing, where the work required a detailed material analysis using various research techniques, such as XRD, XRF, SEM and digital microscopy. The obtained results will allow for further research on developing the concept of technology for the production of lightweight aggregates used, for example, on building roofs. Particular attention was paid to the flat shape of the aggregate, which affects a number of its properties. To obtain a flat-shaped aggregate, the authors used a patented sieving method. The obtained materials had high cavernosity of 69% on average, water absorption of 40.7% and low bulk density of 0.82 g/cm3.

Strengthening complex concentrated alloy without ductility loss by 3D printed high-density coherent nanoparticles

Metallic 3D printing enables fast fabrication of net-shaped components for broad engineering applications, yet it restrains the use of most mechanical processing methods for strengthening alloys, e.g. forging, rolling, etc. Here, we proposed a new strategy for enhancing the strength of 3D printed complex concentrated alloys without losing ductility. This strategy relies on the rapid cooling of 3D printing to achieve a supersaturation state that is beyond conventional casting. Then, spinodal decomposition via aging is exploited to introduce high-density coherent nanoparticles for strengthening. The proposed strategy is demonstrated in a 3D printed Cu-based complex concentrated alloy. The rapid solidification during printing strongly inhibits elemental diffusion, leading to a high supersaturation state. High-density nanoparticles with coherent interface and size of ∼7 nm are introduced into the 3D printed samples through spinodal decomposition via simple aging treatment. The strength of the 3D printed alloy is increased by 30 % after aging with no ductility loss, leading to a strength-ductility combination superior to other Cu alloys. This strategy is readily applicable to other spinodal alloys fabricated by 3D printing for circumventing the strength-ductility trade-off dilemma.

Investigation of processing characteristics of PCD in ultrasonic-assisted graphene powder mixed EDM

Polycrystalline diamond is widely used in many fields including ultra-precise machining, optical material and semiconductor electronic devices due to its excellent physical properties. However, traditional mechanical processing methods of polycrystalline diamond leads to severe tool wear, low efficiency and high costs. Although electrical discharge machining can overcome some limitations, it usually exhibits a low material removal rate and poor surface quality. This study aims to explore the effect of graphene powder and ultrasonic vibration on polycrystalline diamond by electrical discharge machining. It was found that the synergistic effect of graphene powder and ultrasonic vibration can achieve a good surface quality. The results show that ultrasonic-assisted powder mixed electrical discharge machining can obtain the smallest surface roughness (1.98 μm) at low parameter and the biggest material removal rate (0.773 mg/min) at high parameter compared with ultrasonic assisted electrical discharge machining and powder mixed electrical discharge machining. In addition, after ultrasonic-assisted powder mixed electrical discharge machining, the minimum value (0.807) of ID/IG is obtained. For polycrystalline diamond, this study also proposes a removal mechanism that diamond converts into graphite and is peeled under tensile stress.

Effect of laser incidence angle on the femtosecond laser ablation characteristics of silicon carbide ceramics

Due to their excellent physical and chemical properties, silicon carbide ceramics have become representative high-performance materials in aerospace, energy power, biomedical, and other fields. However, as a typical hard and brittle material, silicon carbide ceramics possess incredibly high hardness and brittleness, which pose challenges to traditional mechanical processing methods. Laser processing, as a non-contact method, offers a wide processing range and high processing efficiency and has broad application prospects in the field of hard and brittle material processing. In this paper, laser ablations of silicon carbide ceramics with various combinations of process parameters were carried out by using a five-axis infrared femtosecond laser processing system. The changes in the ablation morphology with different incidence angles and laser power were discussed. The results demonstrate that the ablation threshold of silicon carbide ceramics initially increases, then decreases, and finally increases with the increase of laser incident angle. This trend may be attributed to the effect of the incidence angle on the laser absorption rate of silicon carbide ceramics. The ablation morphology of silicon carbide ceramics can be divided into three zones based on color and oxygen distribution: the ablation removal zone, ablation edge zone, and ablation affected zone. At the same laser incidence angle, the ablation range and depth gradually increase with the increase in laser power, but the growth rate gradually decreases. Furthermore, at the same laser power, as the incident angle increases, the laser energy density gradually decreases, and the long axis of the actual ablation area gradually lengthens while the short axis gradually shortens. This work could provides technical and theoretical support for laser surface processing at multiple incidence angles, which is conducive to multi-axis processing of complex curved parts.

Precise patterning of carbon films on polyethylene terephthalate polymer substrates using femtosecond lasers

A carbon film on a polyethylene terephthalate (PET) substrate is a novel type of flexible laminated material with unique mechanical and electrical properties, making it suitable for the fabrication of various flexible electronic components. However, due to its micron-level thickness, conventional mechanical processing methods are incapable of precisely removing the carbon film without damaging the substrate. Femtosecond laser processing is an advanced technique for achieving precise etching of thin-film materials due to its non-contact, high-precision, and minimal thermal effects. Therefore, we use femtosecond lasers to achieve precision etching of carbon resistive films on PET substrates to minimize substrate damage. In this study, a series of orthogonal and single-factor experiments were conducted to optimize the laser processing parameters. Various measurement and characterization methods, including X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, ultraviolet–visible spectroscopy, and confocal microscopy, were employed to analyze the removal of the carbon layer, changes in light transmittance, surface quality, and chemical composition of the processed substrate. Furthermore, the mechanisms of carbon film removal and PET substrate damage are explained.

Deposition, Dietary Exposure and Human Health Risks of Heavy Metals in Mechanically Milled Maize Flours in Mbarara City, Uganda.

Consumption of maize and maize-based products contributes a significant percentage to the total food energy intake in Uganda. However, the production of maize-derived foodstuffs is performed traditionally or by small- and medium-scale processors using different processing techniques. This can lead to differences in the quality of these products from processors, raising food safety concerns. In this study, the effects of mechanical processing (milling) methods on deposition of heavy metals into milled maize flour and the associated consumption health risks were assessed. Atomic absorption spectrophotometry was used to quantitatively establish the concentration of iron (Fe), manganese (Mn), zinc (Zn), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), cobalt (Co) and nickel (Ni) in 100 samples of maize milled using a wooden mortar (n = 2), a metallic mortar (n = 2), diesel engine-powered mills (n = 48) and electric motor-powered mills (n = 48). Results showed that the mean concentrations of heavy metals in mg/kg were Fe (11.60-34.45), Cu (0.50-8.10), Ni (0.50-1.60), Mn (0.70-25.40), Zn (4.40-15.90), Pb (0.53-10.20), Cd (0.51-0.85), Cr (0.50-1.53) and Co (0.50-1.51). The highest concentrations were found in flour milled using a traditional metallic mortar while the lowest levels were in those samples milled using a wooden mortar. The Fe, Pb and Cd contents of flours produced using the metallic mortar and some commercial mills was found to be higher than the permissible limits set by WHO/FAO. Human health risk assessment showed that there are potential carcinogenic health risks from adults' intake of heavy metals in maize flour milled using a metallic mortar. Therefore, processing of maize flour needs to be monitored by the relevant statutory bodies in Uganda to minimize the possibility of heavy metal contamination of food products and animal feeds.

CONVERGENCE TECHNOLOGY FOR VEHICLE PART SURFACE FINISHING

The subject of this research is convergence technology for the surface finishing of vehicle parts. A literature review has been conducted to carry out a comparative analysis of existing methods for the surface finishing of parts used in the manufacturing of aircraft, hydraulic and pneumatic devices, and other vehicles. Prospects are shown for further research on methods with the aim of creating a complex technology (i.e., convergence) that combines information technologies; nanotechnologies; and thermochemical, electrochemical, and mechanical processing methods. A method is proposed for selecting and combining surface finishing methods according to a five-point expert assessment, which allows the batch processing of vehicle parts. Based on this method, the concept of convergence technology for the surface finishing of vehicle parts is proposed, which includes the impulse thermal energy method, honing, superfinishing, and electrochemical processing. An expanded process is presented for manufacturing parts with high-precision, low-roughness surfaces and a specified microrelief by using electrochemical superfinishing and electrochemical honing. A scheme of the concentration (focusing) of the current flow during electrochemical superfinishing due to the movement of the electrode relative to the part surface is proposed, which enables the effect of surface polishing and the removal of oxidation products. Convergence technology for the surface finishing of vehicle parts will provide parts’ geometric dimensions with micro- and nano-precision and allow the precision machining of small-diameter holes and complex profiles, increased machining accuracy (up to 0.001 microns), the possibility of batch processing, and the possibility of process automation.

Improving the technology of surface preparation of titanium alloys before the processing process

Modern production classifies conventional methods of mechanical processing of titanium parts as unproductive and economically unprofitable. New methods of machining are provided by changing the very nature of the mechanical action on the cut layer of the workpiece. This includes the use of chemical, electrical and thermal types of exposure. Combined manufacturing methods are also used, consisting in a combination of mechanical and physical effects. The main direction of new processing methods is associated with a decrease in the vibration activity of the technological system, leading to an increase in the quality and accuracy of the surface being machined, as well as to an increase in tool life. This is especially important in the machining of hard-to-machine metals based on titanium, since the manufacturing process is associated with the occurrence of unstable self-oscillations when crossing a previously prepared zone of local plastic deformation. In this regard, this work is devoted to the choice of the interaction of deforming tools with the machined surface of a workpiece made of titanium alloys and the combination of regime parameters in the direction of supply and application of forces to the depth of plastic deformation.

Аналіз конструктивних особливостей різних типів коробок перемикання передач автомобілів

One of the important components of the car design is the gearbox, which is part of the transmission. It is the gearbox that is responsible for changing the direction of the car and its speed. This affects traction and dynamic properties in general. The purpose of this article is to analyze the design features of various types of car gearboxes. The work analyzes the design features of various types of car gearboxes. The purpose of the gearbox, the effect on the traction-speed properties, which are a set of properties that determine the possible speed ranges and the maximum intensity of acceleration when the car is moving in the traction mode in various operating conditions, are given, as well as the main requirements that it should provide. The peculiarities of the construction of mechanical gearboxes, their structure, the principle of operation and the possibility of placement in a car are considered. The structure and main elements of the hydromechanical transmission (HMT) design are presented. It consists of three main parts: a torque converter, a manual gearbox and a control system. The design features of the gearbox with V-belt and toroid variators are considered. The principle of operation of variators, which ensures a stepless change of the gear ratio within the established limits, is presented. The design of the gearbox with a double clutch is considered, which ensures uninterrupted transmission of the power flow to the drive wheels. The gearbox is controlled by an electronic control unit, which receives information from sensors located in the box and is connected by a high-speed bus to the engine's electronic control unit. The main advantages and disadvantages of each type of considered gearboxes are highlighted. The mechanical gearbox has proven itself as a unit that is simple in design and reliable in operation. The prospects for the development of the gearbox are the development of new electronic control systems, the use of modern materials with high performance indicators and the use of high-performance methods of mechanical processing.

RELATIONSHIP BETWEEN TEMPERATURE AND SPEED OF TURNING PROCESS OF AISI1045 STEEL BY ST3000 ALLOY

Today, mechanical processing is the main method of processing steel and cast iron. Since mechanical processing methods are more accurate than others. Turning is the most basic process in machining, in the turning are used many types of cutting tools are made of different materials. The most important cutting tool property is its durability. The durability of the cutting tool defines the lifetime of this cutting tool and it determines its suitability for select technological operations. Nonetheless, studies show that durability depends on cutting speed and mode. Nowadays, the durability of the cutting tool is determined by a formula in analytical and empirical ways, and also modeling methods are widely used. In this study, we use AdvantEdge to determine the relationship between the temperature at the cutting zone and cutting speed. The analysis results show that the temperature at the cutting zone (245à239.49à226.2770С) decreases as the cutting speed increases. As researchers, we believe that a large amount of the heat generated with increasing cutting speed was removed from the workpiece by the chip.

Atomic-scale surface of fused silica induced by chemical mechanical polishing with controlled size spherical ceria abrasives

Fused silica is widely used in precision optical devices for its excellent optical properties. However, it has hard and brittle nature, becoming a difficult-to-process material. This makes microscopic cracks left on the processed surface of silica induced by traditional mechanical processing methods. In this regard, it is a challenge to achieve an atomic-scale surface on silica. To overcome this challenge, nanometer CeO2 abrasives with uniform shape and size were prepared via a hydrothermal method. A novel chemical mechanical polishing (CMP) slurry is developed using the prepared CeO2 abrasives, Na2CO3 and deionized water, which is low-cost, non-toxic, and environmentally friendly. The surface roughness, Sa of fused silica after CMP is 0.093 nm with a scanning area of 20 × 20 μm2. To the best of our knowledge, it is the lowest surface roughness on silica after CMP. The CMP mechanism was investigated by X-ray photoelectron spectroscopy and infrared Fourier transformation. Under alkaline conditions, the abrasives interacted with the silica forming a CeOSi reaction product, through a chemical tooth action, which is significant to produce an atomic-scale surface on silica. These findings provide a new pathway to fabricate atomic-scale surface for a hard-brittle solid.

Benchmarking the Production of Cellulose Nanofibres: Biomass Feedstock, Mechanical Processing, and Nanopaper Performance

Lignocellulosic biomass plays a vital role in the global shift away from the utilisation of non-renewable petrochemical resources. An emerging class of biomass-derived material is nanocellulose, which are typically generated from the deconstruction of cellulose bundles within the cell wall of terrestrial and aquatic plants, either in the form of cellulose nanocrystals (CNCs) or cellulose nanofibres (CNFs). However, the utilisation of biomass has an inherent challenge associated with product variability, both in terms of the starting feedstock properties, the wide range of processing routes available to generate nanocellulose, and the fabrication of nanocellulose into a diverse range of different product formats. As a result, it is difficult to accurately characterise and benchmark the wide variety of nanocellulose materials described within the literature. To address this challenge, this study presents a threefold benchmarking assessment of CNF-based material, including: (1) CNFs generated from different biomass sources (sorghum, banana, sugarcane, spinifex, and softwood); (2) CNFs generated through different mechanical processing methods (Silverson mixing, twin-screw extrusion, bead milling, and high pressure homogenisation); and (3) Energy-standardised nanopaper mechanical performance presented within applicable literature studies. The biomass benchmarking study highlighted sorghum and banana stem as comparatively sustainable biomass feedstock, while the mechanical process benchmarking study highlighted twin-screw extrusion as a promising fibrillation method with relatively low energy consumption. Lastly, the nanopaper benchmarking study aided in the visualisation of the nanopaper research landscape. Overall, sample benchmarking in this manner provides greater insight into the mechanisms driving nanocellulose material performance and processing sustainability.

Synthesis, characterization and cutting performances of gradient gradual changing (GGC-) MCD/SMCD/NCD/UNCD diamond coatings with tailored interfacial integrity on CFRP drilling tools

Drilling holes is a common mechanical processing method in the high-precision machining of carbon fiber reinforced plastic (CFRP) material. Diamond coatings can be deposited on the drilling tools to enhance the tool life and improve the machining quality. However, traditional multilayer diamond coatings, such as MCD/NCD etc., easily suffer from interfacial separation in actual applications due to the sharp interfaces of diamond layers. Novel gradient gradual changing (GGC-) structure without clear interfaces is applied to tailor the architecture of diamond coatings, which can lead to superior interfacial integrity and the reduction of sp2 phase content at the transition between distinct diamond layers. Various diamond films, containing monolayer diamond films (MCD, SMCD, NCD, UNCD) and gradient gradual changing multilayer diamond films (GGC-MCD/SMCD/NCD, GGC-MCD/SMCD/NCD/UNCD), were fabricated on WC-Co samples. The deposition of tailored gradient gradual changing coating interfacial architecture can be accomplished by controlling the linear variation of carbon concentration and gas pressure simultaneously. The complementary characteristics of high coating-substrate adhesive strength, superior frictional and wear resistance, good interfacial integrity and favorable crack propagation resistance are concentrated on GGC-MCD/SMCD/NCD and GGC-MCD/SMCD/NCD/UNCD coatings compared to monolayer MCD, SMCD, NCD and UNCD coatings. Moreover, because of the existence of UNCD layer, GGC-MCD/SMCD/NCD/UNCD coating performs lower surface roughness, frictional coefficient and higher surface smoothness than GGC-MCD/SMCD/NCD coating. Besides, the cutting performances in high-speed drilling experiments of CFRP laminates using different types of diamond coated drilling tools were compared systematically, showing that the dominant wear modes are abrasive wear and adhesive wear, and the GGC-MCD/SMCD/NCD/UNCD coated drilling tool exhibits the longest tool lifetime and best machining quality because of the overall interfacial integrity and high surface smoothness.

Macroscopic Architecture Design of Lithium Metal Electrodes: Impacts of Millimeter-Size Hollows on Economization, Cyclability, and Utilization

Abstract A macroscopic architecture design of lithium metal electrodes for solving the problem of extremely excessive lithium metal is proposed in this paper. By employing a simple mechanical processing method, macroscopic hollows within lithium foils are introduced, and consequently, the amount of lithium metal has economized significantly. The cyclability of lithium foils with millimeter-size hollows is evaluated jointly via modeling and experiments. The results suggest that the well-designed macroscopic hollow causes controllable sacrifices of battery cycling performances and considerably boosts the utilization of lithium metal. The relationship of economization, cyclability, and utilization of lithium metal is also discussed. The universality of the results is also verified in different battery systems. Meanwhile, the initial hollows are found to heal morphologically after a series of electrochemical cycles, and the existence of lithium metal in the healing product is also confirmed, indicating that hollows provide room for the in-plane lithium dendrite growth. Based on these findings, this work provides a new perspective on the architectural design of lithium metal electrodes.

Effect of Nb on microstructure and mechanical properties between base metal and high heat input coarse-grain HAZ in a Ti-deoxidized low carbon high strength steel

In this paper, a Ti-deoxidized low carbon high strength steel plate with different Nb content was obtained by thermal mechanical control processing (TMCP) methods. The coarse-grain heat-affected zone (CGHAZ) under high heat input of 300 kJ/cm conditions was simulated. The effects of Nb on microstructure and mechanical properties in base metal (BM) and CGHAZ were analyzed. The results showed that high content of Nb addition is not conducive to the improvement of toughness, especially in high heat input CGHAZ. A certain amount of Nb inhibites the formation of ferrite, while promotes the bainite transformation with coarse carbides during high heat input welding process. Although high-angle grain boundary has a certain hindrance to the crack propagation, the coarse carbides caused by the enhanced hardenability in Nb-bearing steels stimulates the crack initiation sensitively. Besides, the uneven prior austenite grains may also take responsibility to the deterioration of toughness in Nb-bearing CGHAZ. In general, the content of Nb should be carefully added when impact toughness of CGHAZ is considered during high heat input welding in Ti-deoxidized low carbon high strength steel.

MAIN TECHNOLOGICAL FACTORS DETERMINING THE EFFICIENCY AND QUALITY OF THE VIBRATION PROCESS

The factors that determine the efficiency and quality of vibration treatment are indicated. Characteristic cases of interaction of abrasive granules with the processed surface are noted. The influence of the hardness of the processed part material and the shape of its surface, as well as the influence of chemically active solutions on the efficiency and quality of vibration processing, is substantiated. The characteristics of abrasive granules and their volume ratio with the processed parts are given. It is indicated that the underestimation of the possibilities of vibration processing technologies is explained by their insufficient studies. It has been established that vibration processing, depending on the characteristics and composition of the processing medium, is a mechanical or mechanochemical removal of the smallest particles of metal or its oxides and plastic deformation of microroughness due to mutual collisions of the medium granules with the processed surface, caused by vibrations of the reservoir in which the processing medium and, the processed parts are placed. It is noted that, according to the classification, vibration treatment refers to mechanical processing methods and, in particular, to the group of mechanical-chemical processing methods or to combined methods when chemically active solutions are introduced into the working medium, It is also noted that vibration treatment refers to dynamic, and for technological purposes – to dimensionless processing methods, according to the type of tool used - to the group of processing methods with a free abrasive. It has been established that the efficiency of vibration processing depends on the oscillation modes of the vibrating machine, the mass of the processed parts and abrasive granules, the hardness of the parts material and the shape of their treated surfaces, the characteristics of the abrasive medium, the volume ratio of the parts and abrasive granules, as well as on the composition of the chemically active solution. The characteristic cases of interaction of abrasive granules with the processed surface are given. The situations of the highest processing productivity for performing the operations of vibration grinding, vibration polishing, washing and descaling have been established. It is noted how the hardness of the processed part and the shape of their surface affects the performance and quality of vibration processing operations. The characteristics of the working medium, which affects the efficiency and quality of vibration treatment, are given, including the influence of grain size and hardness of the material of abrasive granules. The volume ratios of abrasive and processed parts are considered. The types of actions on the vibration treatment processes are given.

Evaluating the effect of finely ground, dry-rolled, and crumbled corn grain on performance, feeding behavior, and starch digestion in Holstein dairy heifers

Corn processing methods including finely ground (FGC), dry rolled (DRC), and crumbled corn (CRC) were evaluated to determine their effects on average daily gain (ADG), structural growth, starch digestibility, feeding behavior, and blood metabolites of young dairy heifers. In this study, 36 Holstein heifers [91 ± 4 d of age, 105 ± 6.5 kg of body weight (BW); mean ± standard deviation] housed in 9 pens (4 heifers per pen) were fed diets (dry matter basis) containing 20% forage (wheat straw) and 80% corn-based concentrate for 60 d. Pens were randomly assigned to 1 of 3 dietary treatments based on the type of corn grain used for the diets: (1) ground corn (FGC; fine: 1.11 ± 0.52 mm); (2) dry-rolled corn (DRC; 2.30 ± 0.68 mm); and (3) crumbled corn (CRC; 2.54 ± 0.70 mm). Heifers had ad libitum access to diets and water throughout the experiment and the feed intake was measured daily. Animals were weighed at the beginning (91 d of age) and end (151 d of age) of the study. The ADG (kg of BW/d) was calculated at the end of experiment at an individual level. Feeding behavior was recorded based on direct observation by monitoring each heifer every 5 min during a 22-h period at 150 d of age. The CRC and DRC tended to increase feed intake compared with FGC, whereas heifers fed CRC tended to have a greater withers height compared with other treatments. Feed efficiency was not affected; however, ADG and final BW increased in heifers fed the CRC diet compared with other diets. Feeding CRC increased total-tract starch digestibility compared with FGC and DRC diets (97.8 vs. 93.1 and 89.5%, respectively). Compared with FGC diet, feeding DRC and CRC tended to increase rumination time. The molar proportion of propionate was greater, and the molar proportion of acetate and acetate-to-propionate ratio were lower in heifers fed CRC than in those fed DRC. The blood glucose and insulin-like growth factor concentrations increased in heifers fed CRC compared with feeding DRC; however, blood urea concentrations decreased by CRC feeding. In conclusion, thermal processing (CRC diet) improved total-tract starch digestibility, ADG, feed intake, and skeletal growth, but had no effect on feed efficiency during the experimental period. Our results indicated that the thermal processing of corn grain improved growth performance of weaned heifers; however, the performance of heifers over a 60-d period did not differ between mechanical processing methods (grinding and dry rolling).