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Based on the advantages of laser shock forming, such as high-speed dynamic loading, good filling ability of die cavity, and improving material formability along with its other advantages of warm forming to improve forming discreteness and further develop formability, a warm laser shock micro-heading forming (WLSMHF) method was investigated, and an experimental system was established. Combining ALE method in ABAQUS with experiment, the feasibility was studied with T2 copper. The propagation of stress wave, deformation process, and material flow law was studied. The influence of laser energy, temperature, and grain size on the deformation of upsetting head was studied. The influence of forming temperature and grain size on forming discreteness was analyzed. Results show that the phenomenon of the anti-Taylor anvil impact test first appears in the whole rod. When the inside of the die is filled with material, the deformation of the material outside the die is similar to that of micro-upsetting. The upper end of the upsetting head is slightly larger than the lower end because of the propagation of stress wave, inertia effect, and the restraint of the die to the material. The flow speed of the metal material in the die is fast, the die is filled well, and the filling property of the die is good. The deformation of upsetting head increases with the laser energy and temperature, which improves the formability of the material. The deformation of the upsetting head increases with the grain size, and the effect of grain size on forming can be reduced by increasing the forming temperature simultaneously. The increase in the forming temperature and decrease in the grain size can improve the discreteness of the forming size and forming accuracy, respectively.

Dissimilar micro-friction stir welding (dissimilar μFSW) can be a preferred choice for joining dissimilar materials having thickness ≤ 1000 μm. The technique's potential applications are in miniaturized components, where the inherent benefits of the process, such as low temperature, low distortion, and clean joining, are advantageous compared to fusion welding. However, the challenges associated with dissimilar μFSW hinder its full potential applications in the relevant industries. The challenges are particularly a combination of two different characteristics of the process (i) the complexities of simultaneously fulfilling the dissimilar materials' demands due to the vast differences in the two materials' mechanical and thermal properties and (ii) the problems due to reduced sheet thickness. In this regard, the present work is a comprehensive and timely review of the research works done on dissimilar μFSW targeted at easily acquainting the research community about the know-how and the state of the art of the process. The review is broadly divided into three crucial parts: the process inputs/requisites, process mechanics, and process performance. The details about the μFSW tool, process parameters, and relative sheet positioning are discussed under the heading process inputs/requisites. Concerning the process mechanics, the intermetallic compound formation, defect generation, and material mixing are discussed. The joints' resulting performance is shown by detailing the essential properties such as formability, residual stresses, fatigue, hardness, and tensile strength. Additionally, several future research directions are presented at the end of this critical review to motivate further improvements in this joining technique and instigate its utility in relevant industries.

Nowadays industries are taking strength enhancement and weight reduction its main criteria’s for selecting any material. This paper analyses the process of slow speed, shape heading forging where the initially circular porous aluminum powder specimen fixed by one of its ends, is headed into a circular shaped head rivet by appropriate yield criterion, friction law and using an upper bound approach. For the relative average forging pressure of the specimen for different strain intensity, a mathematical model was formulated. The specimens were prepared and subjected to upset rivet head forging process for strain rates of 1.5, 50, 100 and 150 mm/min under lubricated end conditions. Parametric analysis showing deviation of the average forging pressure with percentage reduction in height during rivet head forging process was done graphically. Theoretically and experimentally obtained values of forging load versus percentage reduction in height of the specimen during the process were plotted and a satisfactory equivalence was perceived. Effects of strain rate on load forging during the process of forming the circular rivet head versus percentage height reduction were analyzed and critically addressed.

The centralized production of fuels, chemicals, and fertilizers by thermocatalytic processes sustained by fossil resources is a pillar of modern societies. Electrocatalytic transformations of the abundant small molecules, water, carbon dioxide, dinitrogen, and methane, are emerging routes. Their coupling with renewable sources such as sun power may give rise to a distributed model based on small-scale reactors, so-called artificial leaves. Realizing this vision calls for improved catalytic performance, efforts on reactor and process engineering, and supportive regulatory frameworks. This work puts emphasis in analyzing the core challenge of catalytic performance by defining a common set of figures of merit. This analysis is nuanced by peculiarities inherent to the proposed scheme. This perspective thus aspires to (1) provide a bird’s-eye view of the gap separating them from practical values, (2) identify sources of inefficiency, and (3) establish a qualitative comparison among their feasibility, resulting in H2O ≫ CO2 ≥ N2 > CH4.

The effect of electron plasma removal of scale, flaws, and various contaminants from the surface of rolled steel bars on the structure, properties and surface quality of the rolled articles for cold heading is studied.

The relevance of the study is explained by the fact that most of the base metal, noble metal and rare metal ores are extracted in difficult conditions, where the use of high-performance equipment is impossible. The alternative mining of that sort of ore bodies is chosen as a result of a compromise between extraction rating and quality of the produced ore. It is considered, that the longwall ore breaking in form of pit bank is the most effective one. Other options are considered as cost-intensive because of special drifting for ore breaking. The aim of the study is to prove, that the alternative options of ore production under the same conditions can compete with the main option upon performance and quality indicators, being much safer, excluding the presence of people in work in the mined-out area. The main method of the research is modeling of mining indexes in experimental blocks when conditions in a specific deposit are met. The obtained indicators are systematized and interpreted graphically. Results. The paper introduces the results of modeling the options of the heading system: the option of the bank ore breaking in the stopping zone is compared with the one of the ore breaking from the drilling room: sublevel drifts and risings. The authors have determined the quantitative indicators of alternative options. It is determined that the labour intensity of the drilling room sinking is compensated by the convenience of ore delivery and relative operating safety. It is proved that the options of the heading and room-and-pillar systems, using the drilling factor in the solid ore in special pits and ore breaking by the direct action of the explosion are economically sounder and safer. Conclusions. With little difference in the parameters of the compared options, the increasing labour intensity sinking of the special drilling rooms for ore breaking is compensated by cost saving in ore delivery when the ore bar is created using the direct action of the explosion.

Relevant evidence of rice quality responses to increased temperatures under field condition has been obtained in our previous study. Understanding the intrinsic mechanism of increased temperatures and fertilizer treatment in regulating rice quality formation will be contributed to the development of mitigation measures suitable for actual field operations and to cope with climate warming. This study investigated the potential role of nitrogen fertilizer in regulating the rice quality under field warming through identifying starch-related property indicators. Results showed application of nitrogen fertilizer at heading stage effectively delayed the significantly increased accumulation of total starch, amylose and amylopectin, and reduced the starch particle size, chain length distribution, and crystal structure induced by high temperature, which further compensated the deterioration of rice quality caused by elevated temperature.

The most common method to eliminate post-mining voids created after hard coal mining consists in natural filling them with rock rubble from the strata forming the roof the mining heading. Such rubble is characterized by free spaces that allow uncontrolled flow of air. The said flow is unfavorable due to disturbances in the distribution of airflow in the ventilation network, and it poses the risk of endogenous fire. One way to reduce such adverse phenomena is to fill the rubble with fine-fraction hydraulic mixtures, most frequently fly ash-water mixtures. The first part of the paper presents the method for determining the theoretical porosity of caving rubble. In the second part, the possibility of various degree of sealing of the numerically modelled caving rubble with a fine-fraction hydromixture was investigated in terms of assessing its impact on the ventilation parameters of a longwall working ventilated with the “Y” method. The presented numerical model was used to calculate the airflow distribution at various filling degrees of the rubble. The obtained knowledge involving the changes in the airflow distribution parameters, depending on the sealing degree of the rubble allows to define the possibility to slow down or to stop the development process of endogenous fire. In addition, it also allows to forecast the ventilation conditions of workings in the longwall area, limiting the development of other ventilation-related hazards, such as methane or climate hazards.

Products with a high level of physical and mechanical properties can be obtained either through the use of new materials, or through the development of new technological processes for their production. In this regard, increasingly higher requirements are imposed on metals and alloys as the main structural materials in terms of strength and plastic properties, formability, corrosion resistance and service life, as well as special and new functional characteristics. At the same time, there is a growing need to reduce labor costs, to save solutions to increasingly acute environmental problems. A widely spread and most productive way to obtain finished metal articles with high structural and mechanical properties are methods of cold heading out of rolled metal, which must have a certain quality - the required plasticity, uniform structure and process parameters along the full length, as well as soundness. In conditions of fierce competition in order to improve the quality of the upset metal articles, the enterprises are forced to find reserves at all the points of the process chain for transformation of the original rolled metal. The greatest effect is achieved by the excluding of energy-consuming and labor-intensive annealing in protective gas furnaces and control of surface defects by etching or mechanical operations. This paper is presenting an economical and environment-friendly technology for structural and mechanical maintenance of high quality of rolled stock for upsetting of metal articles. It is shown that drawing with rational degrees at each of the three stages of reduction after annealing with heating by high-frequency currents ensures the absence of mill scale and ellipticity. The minor oxide layer present was removed in the pickling baths within a few seconds. The rolled steel prepared by this technology has a highly dispersed equally spaced structure without a decarburized layer with increased plasticity, which enables to reduce the number of transitions in the process of upsetting of metal articles and to increase the tools service life. At the same time, there are no harmful emissions from annealing furnaces for rolled products and pickling solutions are less often refreshed.

Mine disasters, as associated problems in the development of coal resources, always threaten the life safety of miners and the production safety of enterprises. In coal roadway excavation, the coal in front of the excavation face is in a state of concentrated stress and the deformation is serious. The instability of the coal seam under stress is an important cause of the occurrence of coal and gas outburst. Thus, knowing the mechanical characteristics of surrounding rock in front of the working face is of great significance for deep understanding and effective prevention and control of coal-rock dynamic disasters. By analyzing the characteristics of stress evolution and deformation and failure in front of the heading face, the analytical solution of plastic region distribution in front of the heading face is obtained. According to the established mechanical model, MATLAB numerical calculation software is used to analyze different examples. The influence of different mechanical parameters on the stress state of the working face is studied. The influence parameters of the morphological characteristics of the plastic region are determined, and the change law and characteristics of the plastic region in front of the working face are studied. At the same time, through the characteristics of stress field, the working face dynamic risk assessment of coal and rock dynamic disaster can be realized, which can provide a powerful guarantee for the prevention and control of gas dynamic disasters in deep mine.

This system was designed to automate the chain lubrication system for two wheeled automobiles particularly chain based vehicles. A chain is a movement of traveling day by day heading with an approach to attract the teeth of a sprocket and transmit force and development. To prevent the chain to cut off or rust, need to feed an oil to the chain much of the time. Oil of chains is certainly not a direct task daily there is a need to intensely watch the condition of the chain from time to time for oiling up it when the chain gets dried. To anticipate the chain to cut off or rust there constantly a need to grease ups the chain frequently. Nowadays Grease of chains is definitely not a straightforward assignment, there is a need to acutely watch the state of the chain every so often grease up it when the chain gets dried. An embedded based automatic chain lubrication system is a commonsense strategy to confine wear and the over the top issues it causes. In fact, authentic oil can twofold or even triple the life of two wheeler chains. This system passes on a full extent of chain oil structures, in sprinkle arrangements, to widen chain life, cut individual times, save time and addition benefits.

The methods for the determination of stress state in rock mass using the energy of explosion are substantiated. The industrial tests are performed with a view to sizing zones of squeezing and radial fracturing in mines of Priargunsky Mining and Chemical Works. It is found that the fracturing zone radius decreases and the squeezing zone diameter increases with the grater depth of mining operations. The theoretical formulas for calculating stresses depending on sizes of squeezing and fracturing zones, physical and mechanical properties of rocks and detonation characteristics of explosives are obtained. The validity of the formulas is proved in comparison with the method of stress measurement in parallel drill holes at the Antei deposit of Priargunsky MCW. The method of stress determination by blasting is suitable for operational application during heading in mines.

Laser-assisted machining (LAM) is a type of hybrid material removal process, which is used for locally and instantaneously decreasing the hardness of materials, such as ceramics and hard composites, by irradiating the material with a focused laser during mechanical cutting. LAM, which has been studied primarily for the macro-machining of the hard materials, was applied to the micro-turning process of high hardness steel for a micro-lens mold in this research. The laser-assisted micro-turning (LAμT) process was analyzed using finite element modeling to predict the thermal effects and temperature distributions induced by irradiation of a focused laser and to determine critical cutting parameters, such as spot size, heading distance, and feeds. The effects of the LAμT were verified by an in-situ comparison with conventional micro-turning method, and the cutting conditions were optimized to maximize the cutting performances in terms of cutting force, surface finish, and chip exhaust. Consequently, a lower cutting force and better surface finish was demonstrated compared to the conventional method for the optimized LAμT condition. Therefore, this study showed that the LAμT can be successfully applied to the micro-machining of hard molds.

To investigate the effects of the air volume ratio parameters (axial-to-radial flow ratio of the wall-attached air cylinder “δ” and the forced-to-exhaust ratio of the ventilation system “β”) on the air curtain dust suppression in a rock tunnel’s fully-mechanized working face, the eastern belt fully-mechanized working face in Huipodi mining company (Shanxi Mineral Group Co., Ltd., China) was numerically simulated by CFD software in this study. First, a mathematical model for describing the airflow-dust migration in a fully-mechanized working face was established using the Euler-Lagrange method. A full-scale geometrical model of the tunnel was also developed. The effectiveness of the established models and the related parameter settings were then verified by making comparisons between the field measured values and the numerical simulation results. Finally, the airflow migration and dust dispersion rules under different ventilation conditions (δ = 5:5–1:9 and β = 0.5–1.5) were simulated. According to the simulation results, a decrease in δ and β contributed to the formation of an effective axial dust-suppression air curtain in the fully-mechanized excavating region. For eastern belt fully-mechanized working face and those under similar production conditions, an effective axial dust-suppression air curtain can be formed when δ = 1:9–2:8 and β = 0.5–0.75. When δ = 1:9 and β = 0.5–0.75, the high-concentration dust were blocked in the space in front of the driver of heading machine (i.e., within 7 m from the head-on section), which achieved a better dust suppression effect.

Ds-type inclusions during production are an important factor affecting the performance and quality of manufactured 10B21 steel. To minimize Ds-type inclusions in steel and improve the production qualification rate of steelmaking plants, a refining slag system optimization scheme was proposed based on the analysis of current inclusion evolution during the steelmaking process, and industrial tests were conducted to verify improvements resulting from application of the proposed scheme. The results showed that the composition of Ds inclusions in 10B21 steel are mainly CaO–Al2O3–MgO–CaS–TiN, which exists in the form of calcium–magnesium aluminate coated with titanium nitride and calcium sulfide. The main reason for the formation of Ds inclusions is the poor fluidity of the refining slag and its low capability to absorb inclusions. The poor coverage of the refining slag on the molten steel during refining can easily cause secondary oxidation of the molten steel. Thus, the formation and growth of Ds-type inclusions are aggravated after the calcium feeding line and soft blowing operation. Here, we propose to minimize Ds inclusions using our optimized refined slag system. The mass percentage of the optimized slag system is CaO: 55–60%, Al2O3: 20–35%, SiO2: 3–7%, MgO: 4–8%, (MnO + FeO) &lt, 1%, and the basicity is controlled within the range of 7–11. We observed that our optimized refining slag system has a significantly improved ability to remove inclusions, particularly Ds inclusions, which improves the qualification rate of 10B21 steel.

Stress state of rock mass during fully mechanized longwalling in dislocation zone is analyzed. In focus is the variant of crossing the dislocation zone with disassembling the fully mechanized longwall system and its re-assembling in a new room. Stress redistribution in coal and host rocks when heading approaches dislocation and in post-dislocation mining from the new assembling room is determined.

This paper discusses the development of a novel external-spraying injection dedusting device, which has the potential to reduce substantially the amount of dust produced by a heading machine during the cutting process in a fully-mechanized coal face. Firstly, the migration rules of the inner wind flow field are analyzed using numerical simulations, and then the atomization function of the spraying nozzle is optimized. Consequently, the nozzle exhibited the highest airborne dust reduction rate at a spraying pressure of 4 MPa. The proposed device’s functionality was also tested by experiments, with the results indicating that as the spraying pressure increased from 2 MPa to 8 MPa, the gas–liquid ratio increased at first and then decreased, reaching a maximum of 1.269 at a spraying pressure of 4 MPa, which was subsequently once again selected as the optimal spraying pressure. Finally, field experiments were conducted on the developed dedusting device, with the results showing that, compared with the original spraying dust reduction method, when the developed external-spraying injection dedusting device was opened, using the dust reduction method (d), the average dust reduction rates of the total coal and respirable dust are enhanced by 17.0% and 18.3% respectively; moreover, using the dust reduction method (c), the average dust reduction rates of total coal and respirable dust are enhanced by 11.6% and 12.0% respectively. Therefore, it can be calculated that by using the injection dedusting method, the average reduction rates are enhanced by 5.4% and 6.3% respectively. In particular, the use of one of the proposed dust removal methods at the measuring point where the machine’s driver is located, led to the average concentrations of total dust and respirable dust decreasing from 305.1 mg/m 3 and 129.5 mg/m 3 to 88.2 mg/m 3 and 38.3 mg/m 3 respectively.

The key working process carried out by roadheaders is rock mining. For this reason, the mathematical modelling of the mining process is underlying the prediction of a dynamic load on the main components of a roadheader, the prediction of power demand for rock cutting with given properties or the prediction of energy consumption of this process. The theoretical and experimental investigations conducted point out – especially in relation to the technical parameters of roadheaders used these days in underground mining and their operating conditions – that the mathematical models of the process employed to date have many limitations, and in many cases the results obtained using such models deviate largely from the reality. This is due to the fact that certain factors strongly influencing cutting process progress have not been considered at the modelling stage, or have been approached in an oversimplified fashion. The article presents a new model of a rock cutting process using conical picks of cutting heads of boom-type roadheaders. An important novelty with respect to the models applied to date is, firstly, that the actual shape of cuts has been modelled with such shape resulting from the geometry of the currently used conical picks, and, secondly, variations in the depth of cuts in the cutting path of individual picks have been considered with such variations resulting from the picks’ kinematics during the advancement of transverse cutting heads parallel to the floor surface. The work presents examples of simulation results for mining with a roadheader’s transverse head equipped with 80 conical picks and compares them with the outcomes obtained using the existing model.

To solve the problem of dust pollution in the heading face, a new type of external pneumatic vortex fog curtain dust removal device suitable for a fully mechanized excavation face is designed in this paper. Firstly, dust migration laws at different times are simulated and analyzed by COMSOL software, and the functional relationship of dust concentration distribution above 50 mg/m3 at different heights and different wind speed is derived. Aiming at the dust migration laws of the heading face, a new dust removal device was proposed, and the atomization performance of the new type of external pneumatic vortex fog curtain dust removal device under different jet wind speed, different atomization pressure, and different nozzle working angle is explored through atomization performance experiment. It is found that when jet wind speed is 30 m/s, atomization pressure is 4 MPa, and nozzle working angle is 75°, the atomization performance of the new type of external pneumatic vortex fog curtain dust removal device is the best. Through the simulation of COMSOL software, the influence of air volume on the new type of external pneumatic vortex fog curtain dust removal device is analyzed. It is found that the new type of external pneumatic vortex fog curtain dust removal device is relatively stable when the air volume at the pressure outlet is less than 400 m3/min. The dust-reduction efficiency of the new type of external pneumatic vortex fog curtain dust removal device was investigated through the dust-reduction experiment, and it is found that the new type of external pneumatic vortex fog curtain dust removal device had better dust removal performance under the condition that the ventilation conditions did not interfere with the integrity of the vortex fog curtain.

Grain yield of wheat and its components are very sensitive to heat stress at the critical growth stages of anthesis and grain filling. We observed negative impacts of heat stress on biomass partitioning and grain growth in environment-controlled phytotron experiments over 4 years, and we quantified relationships between the stress and grain number and potential grain weight at anthesis and during grain filling using process-based heat stress routines. These relationships included reduced grain set under stress at anthesis and decreased potential grain weight under stress during early grain filling. Biomass partitioning to stems and spikes was modified under heat stress based on a source–sink relationship. The integration of our process-based stress routines into the original WheatGrow model significantly enhanced the predictions of the biomass dynamics of the stems and spikes, the grain yield, and the yield components under heat stress. Compared to the original model, the improved version decreased the simulation errors for grain yield, grain number, and grain weight by 73%, 48%, and 49%, respectively, in an evaluation using independent data under heat stress in the phytotron conditions. When tested with data obtained under field conditions, the improved model showed a good ability to reproduce the decreasing dynamics of grain yield and its components with increasing post-anthesis temperatures. Sensitivity analysis showed that the improved model was able to reproduce the responses to various observed heat-stress treatments. These improvements to the crop model will be of significant importance for assessing the effects on crop production of projected increases in heat-stress events under future climate scenarios.

PVDF piezoelectric film has high natural frequency, piezoelectric constant, fatigue resistance and impact resistance, which is especially suitable for measuring dynamic impact load. The sensor is used to monitor the cold heading process of the steel ball, which improves the production automation level, the processing quality and service life of the steel ball. In this paper, the kinematics model is established based on the actual steel ball cold heading machine. The steel ball cold heading model is established by DEFORM, and its simulation analysis is carried out. According to the simulation, the change law of cold heading force under the influence of different parameters is obtained. It proves that the data measured by the three-dimensional force sensor can judge the defects of cold heading and lay a solid foundation for the application of the three-dimensional force sensor to the production of steel ball cold heading.

This study involves an elastoplastic analysis of the effects of the advance of a double-track railway tunnel on the soil and the tunnel support. The strength and deformation properties have been determined using in-situ testing with equipment designed and patented by the Soil Engineering Research Group at the University of Oviedo (GIITUO). The behaviour of the excavation face and the ideal trace are studied using a 2D model of the longitudinal cross section of the tunnel. In this work one study of the behaviour of the soil and the support during the different phases of excavation is given. From it, it is possible to say that in the initial phases of the excavation and with temporary support there are not significant deformations. Once the final support is applied, the maximum compressive stresses (7MPa) are concentrated in the crown zone and the maximum tensile stresses are in the base of the support of the top heading and the sidewalls (0.15-0.5 MPa).

Covalent adaptable networks (CANs) have recently received extensive interests due to their reprocessability and repairability. Rethinking the libraries of the published CANs, most of them are fabricated by one/two-component reactions and few cases utilize multi-component reactions to construct CANs while multi-component reactions are conductive to tailoring the properties of polymers due to their structural designability and flexible choice of raw materials. A novel kind of dynamic covalent bond named aminoesterenamide is presented through three-component reaction between acetoacetyl, amine and isocyanate. Aminoesterenamide exhibits thermal reversibility through dissociating into vinylogous urethane and isocyanate. When it is used to prepare CANs, the synthesized polymer networks can be reprocessed many times via the exchange reaction between aminoesterenamides. Moreover, the forming of aminoesterenamide involving three starting components imparts CANs with great freedom to tailor their properties. Therefore, the authors believe this method that utilizes three-component reaction to fabricate CANs would bring new stories and perspectives to the exploration of new types of CANs.

The paper studies how the design parameters of the development machines affect the generation intensity of the explosive coal dust. At present, there are about 20 different types of development machines operating in underground coal mines. The operation of these machines produces coal dust in explosive concentrations. When working on improving the design parameters of the development machines, their dust-generating properties must be accounted for. The organic part of coal dust of 30-50 µm size is considered explosive. The article proposes an index of dust-generating intensity for the development machines. The value of this index equals the total length of grooves which are produced by hard-alloy inserts of the machine’s cutter picks within 1 minute. The article presents the dependency relations for calculating the amount of dust produced from 1 m of groove, including its explosive properties. We have also provided a dependency relation between the total length of grooves and the number of cutter picks, the average diameter of the cutter head and revolutions per minute. The underground field research has confirmed the presence of groove tracks at the face and the interrelation of their size and the type of cutter picks used. The article provides estimates of the intensity of dust generation for the currently utilized types of development machines.

Foam technology utilizes the good coverage of foam to form a closed space around dust sources. The foam then wets the dust particles, causing them to adhere before they spread into the air, resulting in better dust control than with water sprays. In the process of foam dust control at a heading face, the foam spray trajectory is highly influenced by the wind, making it difficult to focus foam on the dust sources, which wastes the foam and reduces dust control efficiency. To resolve this problem, the idea of transporting foam to the cutting head through the roadheader’s inner pipeline is proposed. To adapt to the high resistance of foam delivery in the roadheader’s inner pipeline, according to the water and air supply of the heading face, a table water-jet suction device and porous spiral coupling foaming device were designed, and the working conditions were tested using a self-designed experiment system in the laboratory. The results showed that the foaming agent could be automatically added into the device at a working water flow rate of 1–1.6 m3/h at a ratio of 1%. The optimum air flow was 45–50 m3/h, in which range the foam expansion ratio reached the maximum and the outlet pressure demand was satisfied. Field application showed that the new foam method had a better dust control efficiencies than traditional foam methods.

In pursuit of developing environmentally friendly techniques for machining, a lot of hard work has been done by researchers all over the world, and many fruitful results have been obtained. When focussing on cooling techniques, minimum quantity lubrication (MQL) is one such development that has proven to be highly useful in leading to a greener manufacturing process. The need of the hour is not just to compare its (MQL) benefits to dry and flood cooling. Rather, certain improvements need to be introduced in the MQL process to make it more effective and improve its performance. In this study, a similar effort has been made by introducing a Ranque-Hilsch vortex tube into the MQL process. Turning of commercially pure titanium (Grade 2) was commenced using uncoated tungsten carbide inserts. Variations in speed, feed and depth of cut were made. The experiments were designed using response surface methodology, and analysis of variance (ANOVA) was performed to identify the effect of the input parameters on the responses, i.e., surface roughness, cutting force, power and flank wear. Optimizations of the results proved that the Ranque-Hilsch vortex tube made significant improvements in the results and was suggested as a better method. These predictions were experimentally validated, thus making the MQL process more effective with a negligible cost addition and heading to a greener future in manufacturing industry.

Fatigue failure is defined as the progressive degradation of the strength of a structural component during the manufacturing of machine tools. As the increasing demands for high product quality result in a continuing need to achieve improvements in fatigue reliability on machining tools, many researches have been focused on it in recent decades with a result of many valuable contributions. However, current researches always focus on the fatigue analysis of rigid components, and the dimension change, necessary design, and optimization are lacked, while the component of a product is always a rigid-flexible coupling multi-body system, which could affect the accuracy and reliability of fatigue analysis, and parameterization help designers see each dimension change. This paper proposed a process of component fatigue analysis based on rigid-flexible coupling virtual prototyping. In this paper, a crankshaft in the cold heading machine is taken as an example to show the rigid-flexible coupling fatigue analysis process in detail. After the parameterization of the crankshaft is proposed, the static analysis and optimization of the crankshaft is carried out. The dynamics analysis for rigid-flexible coupling of the cold heading components is also proposed. The fatigue analysis for the crankshaft is discussed in detail. The crankshaft in the cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation. The physical prototyping is also carried out to demonstrate the fatigue reliability. The crankshaft of cold heading machine is given as an example, which demonstrates that the methodology is obviously helpful to fatigue analysis and simulation.

Crop yield simulations are highly correlated to reproductive phase duration simulations, which are often affected by heat stress. In this study, we evaluated four widely used temperature response routines of wheat phenology (Bilinear, Sin, Beta, and Trapezoidal routines) to simulate heat stress effects on post-heading durations with datasets from four years of environment-controlled phytotron experiments and multi-year field experiments across the main wheat production region in China. Significant reductions in post-heading duration were observed with increasing heat stress in phytotron experiments. A comparison of these temperature routines imbedded in the WheatGrow model showed that three of the routines could not predict post-heading durations under heat stress, while the Trapezoidal routine tended to overestimate high temperature impacts. Therefore, the three routines that could not simulate heat stress effects were extended by a senescence acceleration function. This function significantly improved the post-heading duration simulations under heat stress, regardless of the original temperature routine. However, the temperature threshold of initiating the senescence acceleration function varied depending on the original temperature response routine, between 27.3 and 30.1 °C. A new genotypic coefficient representing a cultivar-specific sensitivity to heat stress was introduced and ranged from 1.4 to 5.7 times of none heat-affected senescence per day. When evaluating the three temperature response routines linked with the added senescence acceleration function with independent phenology data (130 measurements), resulted in an average RMSE of 2.2 days for post-heading duration. The improved post-heading duration simulation is important for simulating current year-to-year yield variability due to frequent heat events, and it is even more critical for climate change impact assessments.

Aiming at the problems of low dust removal efficiency, poor removal of respiratory dust, and serious waste of water resource, caused by underground wet dust removal device in heading face in the coal mine, and the promotion of coal mine mechanization, informatization, automation, and intelligent construction, we make the development of an intelligent dry dust collector working underground. We adopt new production process to develop the flame-retardant anti-static dust removal filter material without rolling points, which can increase the effective dust removal filter area by more than 20%, greatly reduce the size of the dust collector, and have a total dust removal efficiency of more than 99.5%. We apply automatic intelligent control technology to realize linkage with heading machine, automatic start and stop, intelligent cleaning, fault detection and alarm, and unmanned operation, and to support multiple terminal equipment access, so as to provide complete set of dry dust removal technical support for unmanned dig working face.

Chemistry of coffee, under the heading of biodiversity, covers both general and new aspects of interest: the challenge of an expanding cultivation of coffee; the rise and threat of species; coffee components developing in the fruit, at postharvest treatment, via the roasting process, in the preparation of the beverage; and, finally, the beverage’s effects on humans.

There has been a major development in the material research and applications in industrial and commercial components or products. With the increase in demand of customers for various customized products that need to be durable, functionally reliable and low cost at the same time. These requirements motivate designers and manufacturers to tackle for the challenging task of optimizing the control factors that determines the quality of the final product. Material is one of the control factors that has been extensively analysed since the industrial revolution began using various material tests as described in Chap. 2. In this chapter, the properties, compositions and characteristics of different materials have been described in detail under the heading of all engineering materials used presently in industries and structural works. The production procedure of these materials, processes for heat treatments for altering properties of the material and applications of these materials are described in detail in this chapter.

Aluminum and its alloys represent a common raw material for components released through a cold machining routine (i.e., forging, cold heading, and rolling processes). They offer easy manufacturing and high plastic strength, together with light weight, long life span, and easy recycling and are heavily used in the transport industry (P. M. G. P. Moreira, et al. (1 Moreira, P. M. G. P., de Jesus, A. M. P., Ribeiro, A. S., and de Castro, P. M. S. T. (2008), “Fatigue Crack Growth in Friction Stir Welds of 6082-T6 and 6061-T6 Aluminium Alloys: A Comparison,” Theoretical and Applied Fracture Mechanics, 50, pp 81–91.[Crossref], [Web of Science ®], [Google Scholar]), Theoretical and Applied Fracture Mechanics, 50, pp 81–91, 2008; H. Yoshimura and K. Tanaka (2 Yoshimura, H., and Tanaka, K. (2000), “Precision Forging of Aluminum and Steel,” Journal of Materials Processing Technology, 98, pp 196–204.[Crossref], [Web of Science ®], [Google Scholar]), Journal of Materials Processing Technology, 98, pp 196–204, 2000). However, during processing, the sample–tool interfaces can generate sticking mechanisms that result in an increase in friction values and high wear rates, leading to irreversible damage to the workpiece surface. The surface morphology provides characteristics that allow detection of the damage amplitude. The hard contact between asperities causes nucleation and the formation of adhesive wear. The normal load and lubrication conditions may further affect the quantity of wear elements (A. Hase and H. Mishina (3 Hase, A., and Mishina, H. (2009), “Wear Elements Generated in the Elementary Process of Wear,” Tribology International, 42, pp 1684–1690.[Crossref], [Web of Science ®], [Google Scholar]), Tribology International, 42, pp 1684–1690, 2009). Optical nondestructive observations permit the detection of the quantity of wear elements as per material transfer from one side (specimen surface) to the other side (contactor surface). This article presents the mechanisms of the adhesive layer and material transfer that are directly proportional to the new roughness stature. A robust finite element method analysis was embedded to establish a relationship between time, plastic deformation, friction coefficients, and surface defects.

Cold heading (CH) is a fast and simple metal forming process to fabricate small-sized products for industry applications. Deformed microstructure under dynamic heading greatly influences properties of the products. The main objective of this work is to investigate the effect of the deformed microstructure on mechanical properties in the headed part. Consequently, the cold heading under magnetic pulse force was performed with 2A10 aluminum alloy bars. Microstructure and mechanical properties of the headed part were achieved to explore the relationship between microstructure distribution and mechanical properties. Microstructure observation showed that adiabatic shear bands (ASBs) were a remarkable characteristic of headed part, and caused the inhomogeneous distribution of deformation. The brittle Al2Cu phase particles precipitated in the ASBs. The hardness of ASB was significantly higher than that of other zones that attributed to the dual effects of work hardening and precipitation strengthening. Moreover, inhomogeneous microstructure distribution contributed varied mechanical properties in headed part, where the quasi-static compression yield strength (476 MPa) in its edge position was higher than that (395 MPa) in its central zone. And the specific microstructure from different regions of headed part contributed to varied tensile strain, fracture location and fracture mode.

Carbon emission has become a recent global concern for green manufacturing. Production is one of the main sources of carbon emission. As the design of a product determines over 70 % of its life cycle costs, with extensive impacts on the environment, it is important to decrease the product carbon footprint in the product design stage. As the activity data is directly related to the mass of the product, the lightweight of product is a valid approach to low-carbon footprint. However, the existing lightweight design method primarily takes structure or material into consideration without the consideration of environmental factors. The product lightweight design under the low-carbon footprint constraint is proposed in this paper, which serves low-carbon footprint as an important benchmarking for product performance. This paper then presents a general lightweight design for product low-carbon footprint through structural optimization. The design of a cold heading machine is used to demonstrate the proposed methodology.

To realize a stable addition of foaming agent used for foam technology, a new adding method using the jet cavitation was introduced, and its performance was investigated experimentally under different operating conditions. Experimental results show that the bubble region in the jet device has a constant vapor pressure, which creates a good condition for liquid absorption, while it shrinks with increasing outlet pressure. The liquid absorption amount keeps unchanged when the outlet pressure is lower than a critical value. The critical outlet pressure increases by 40% with decreasing cavitation absorption amount, which is especially suitable for mini-flow quantitative addition of foaming agent used for foam dust suppression. Its effectiveness on suppressing mine dust was evaluated in a heading face of underground coal mines. Field application indicates that the reliable and simple foaming system adopting the new adding method makes a marked dust suppression effect. The working environment of heading face is significantly improved, ensuring the safe tunneling and personal security.

International audience; Tools sustainability and reliability is a key axis for economic competitiveness of companies in the field of cold heading of steels. This durability is currently limited by the damage occurring at the contact surfaces.The main objective of this study is to propose an energy based approach to understand the mechanisms of deterioration of the WC-Co carbide tools.Firstly a finite element simulation of an industrial cold heading process is run in order to identify the contact condition at the tool workpiece interface. Main results are the stress, strain and temperature distributions in the near surface of the tools. A particular attention is paid to the location of critical areas that may limit the tool life.Jointly, characterizations of the morphology of the worn surfaces are performed. SEM observations added to EDS and roughness measurements are done from midlife to end of life of industrial tools. Friction tests are performed with the Upsetting-Sliding Test involving contactors extracted from real worn tools to identify friction coefficients in order to provide the evolution of the friction coefficient according to the wear state of the tools. Finally, the correlation between the numerical analysis and the experimental measurement is discussed to attest to the relevance of the energy fracture based model to explain the deterioration of the tribological conditions

The electrical connectors mostly have silver contacts joined by riveting. In order to reduce costs, the core of the contact rivet can be replaced with cheaper material, e.g. copper. There is a wide range of commercially available bimetallic (silver-copper) rivets on the market for the production of contacts. Following that, new conditions in the riveting process are created because the bi-metal object is riveted. In the analyzed example, it is a small size object, which can be placed on the border of microforming. Based on the FEM modeling of the load process of bimetallic rivets with different material distributions, the desired distribution was chosen and the choice was justified. Possible material distributions were parameterized with two parameters referring to desirable distribution characteristics. The parameter: Coefficient of Mutual Interactions of Plastic Deformations and the method of its determination have been proposed. The parameter is determined based of two-parameter stress-strain curves and is a function of these parameters and the range of equivalent strains occurring in the analyzed process. The proposed method was used for the upsetting process of the bimetallic head of the electrical contact. A nomogram was established to predict the distribution of materials in the head of the rivet and the appropriate selection of a pair of materials to achieve the desired distribution.The electrical connectors mostly have silver contacts joined by riveting. In order to reduce costs, the core of the contact rivet can be replaced with cheaper material, e.g. copper. There is a wide range of commercially available bimetallic (silver-copper) rivets on the market for the production of contacts. Following that, new conditions in the riveting process are created because the bi-metal object is riveted. In the analyzed example, it is a small size object, which can be placed on the border of microforming. Based on the FEM modeling of the load process of bimetallic rivets with different material distributions, the desired distribution was chosen and the choice was justified. Possible material distributions were parameterized with two parameters referring to desirable distribution characteristics. The parameter: Coefficient of Mutual Interactions of Plastic Deformations and the method of its determination have been proposed. The parameter is determined based of two-parameter stress-strain curves an...

This paper deals with the potential role of new hybrid energy systems application along with the heating share concept. It analyses the possibility to develop new plant refurbishment strategy so as to promote the deployment of small scale smart energy systems. Up to now, many new technologies have been implemented can be used for achieving the NZEB objectives. The paper clears up how is possible to share the heat for a small group of dwellings arranged in a single lot. Through the use of a new plant layout for high temperature heat production, it was possible to investigate and compare the results with the typical separated generation systems. Therefore, the new plant design allows the four dwellings to share a cold heat sink able to feed 4 trans-critical CO2 heat pumps. In this way, the four dwellings have been interconnected each other by that hydraulic loop while the electricity is generated by PV arrays and CHP. Outcomes of this comparative analysis has been reported and discussed.

The effect of controlled rolling and cooling on microstructure and mechanical properties of micro-alloyed cold heading steel 6AB-Ti and 35KB-Ti with diameter 6.5 mm was studied. The results showed that the controlled rolling and cooling process had a great effect on the microstructure and properties of 6AB-Ti than 35KB-Ti. For 6AB-Ti steel, the tensile strength value decreased from 460 to 360 MPa and the microstructure evolved from quasi-polygonal ferrite and pearlite to polygonal ferrite and pearlite when the finish rolling decreased from 920 to 850 °C (and the laying head temperature decreased from 900 to 800 °C). For 35KB-Ti steel, the tensile strength decreased from 630 to 610 MPa and the microstructure with ferrite net disappeared for controlled rolling and cooling process. The above phenomena are explained by the CCT curve of steel and the influence of boron and titanium on the phase transformation of steel.

To produce high-quality fasteners for motor group components of automobiles it is necessary to follow the increased requirements to calibrated rolled stock in terms of surface defects. Therefore, the goal of this paper is to study the reasons, types and depth of the surface defects on the calibrated rolled stock from steel 38KHGNM Ø 12.0 mm on the basis of the metallographic analysis. Before cold upsetting, the hot-rolled products are subjected to metal flow and removal of unacceptable surface defects by means of expensive turning operation during which the screw cuts and cracks might appear. It has been defined, that the hot-rolled stock from steel, grade 38KHGNM, diameter 12.0 мм has nonuniform mechanical properties, grooves, laps and partial decarburization on the surface. The heat treatment of the rolled stock with a decarburized layer on the surface contributes to its further decarburization. Poor alignment of calibrated stock during its turning at the turning machine does not enable to completely remove the decarburized layer with minimum skinning of rolled stock. It has been shown that the use of rolled stock from steel 38KHGNM with surface defects and unreasonably high decarburized layer on the surface increases its rejection by 8% and raises the consumption of rolled stock for manufacturing of important fasteners for the motor group of automobiles.

This study targeted the effects of heat treatment on the mechanical properties of high-strength steel bolts. High-strength steel bolt samples were manufactured by sequential cutting, cold forming, heading and heat treatment. All sample bolts were M12, and the material was 30MnB4. During the heat treatment, quenching and tempering were applied to high-strength steel. Stress-strain curves were obtained for the steel bolt samples after different heat treatments. The mechanical properties of the steel bolts, such as yield strength, tensile strength, hardness and elongation, were determined for the various heat treatments. It was concluded that heat treatment is an important process that changes the microstructure of the steel bolts and their mechanical properties. By heat treatment at different temperatures it is possible to obtain high-strength steel bolts with different properties.

In order to make normal rock avalanche but not have significant impact on other parts of surrounding rock and produce evident deformation in the process of blasting heading, the basic mechanical property of rocks in Xishimen Iron Mine was taken as example to analyze. The process of coupling charge blasting in the surrounding holes of smooth blasting was simulated by applying the finite element numerical simulation software ANSYS/ LS-DYNA. The result shows that the surrounding rock has smallest stress and spall normally when borehole spacing of surrounding holes is 0.6m, thus boosting the efficiency of smooth blasting.

Metastable beta titanium alloy Ti-5Mo-5V-8Cr-3Al, with high-strength, favorite ductility and outstanding capacity of cold forming and welding, has been found the applications in sheet metal component, pressure vessel, corrugated shell and cold heading rivet at the temperature lower than 350°C. In the present paper, the effect of cold machining deformation rate and heat treatment process on the properties and microstructures of Ti-5Mo-5V-8Cr-3Al strip were investigated. The results revealed that excellent comprehensive mechanical properties could be achieved with the alloy by reasonable cold machining process and with solution treatment at 800°C followed by gas quenching. Upon a solution and aging treatment at 480°C, the alloy performed favorite plasticity and high ultimate tensile strength of 1250MPa.

Offshore oil and gas exploration are gradually heading toward the deep sea and even the ultra-deep sea. According, the working temperature and pressure intensity of subsea oil and gas pipelines have increased by a considerable degree. This situation is accompanied by the global buckling problem in deep sea pipelines, which has become increasingly common. Meanwhile, ordinary single-layer pipelines cannot last for a long time under harsh deep-sea working conditions. Thus, multilayer pipelines, such as the pipe-in-pipe (PIP) structure and bundled pipelines, have gradually become top choices. However, the global buckling mechanisms of these multilayer pipelines are more complicated than those of single-layer pipelines. The sleeper–snake lay pipeline, which is an active control method for global buckling, was used in this study. The change and development laws of global buckling in a PIP structure at different wavelengths and amplitudes were determined through an experimental study. A dynamic solution method that considers artificial damping was adopted to establish finite element global buckling models of a PIP structure with initial imperfections. The effects of various factors, such as pipeline laying shape, sleeper–pipe function, and seabed–pipe function, on global buckling were analyzed. By the result of finite element method analysis, the initial imperfection, and sleeper–pipeline friction were determined to be the key factors that influenced critical pipeline buckling force. Accordingly, a reference for the design of PIP structures is presented.

More complicated parts having gear teeth, cylindrical grooves, or long branches are manufactured in cold forging. Nowadays, more precise dimensions are required for these parts. Reduction in forming load is a key factor to obtain more precise parts in cold forging, because high load causes the elastically large deformation of tools and machines. Furthermore, this reduction in forming load contributes to longer tool life. In this paper, the loads of split-forging including split-backward extrusion and split-heading to produce the branched parts are estimated under different conditions such as punch sizes, punch geometries, and lubricants.

Recently, manufacturing process simulation using finite element (FE) model become important. Therefore, validation of the finite element model is crucial. This study will present validation of 2D finite element simulation of cold heading at room temperature. Validation of the simulation model is carried out by comparing the resulted bulge profile of the cold upsetting specimen to the profile of the specimen, which is obtained from an optical 3D surface measurement technique namely Infinite Focus Alicona system. Based on the result, both profiles show a very good agreement.

Cold forming generally allows the fast generation of parts with very low tolerances. In addition, mechanical properties are improved, if work hardening materials are used. Transferring the cold forming process to micro range leads to a decrease in the maximum achievable upset ratio so that the forming process becomes inefficient. Therefore, a laser-based free form heading process has been developed to generate preforms which can be calibrated in a secondary cold forming step. The achievable upset ratios reach values of several hundreds instead of 2.1 which is common for single step mechanical upsetting. In this article, heat losses arising in the material accumulation process using laser-based free form heading are analyzed and discussed. For this purpose, the process is modeled within the framework of continuum mechanics and simulated by a finite element method. By using a numerical approach, a systematic study on heat losses is performed in order to identify the influence of radiation, heat transfer due to convection and thermal conduction during laser irradiation time. The simulation results, which are validated with experimental data, show that the radiation is the most important mechanism reducing the efficiency of the accumulation process.

A laser-based micro upsetting process is presented which takes advantage of scaling effects in order to optimize the conventional multistage upsetting process. Due to the fact that the surface tension exceeds the gravitation force with increasing miniaturization, in the microrange, an accumulation of molten material forms a nearly perfect sphere. This material accumulation can be finally formed in a secondary process step. In former investigations, it has been shown that the laser-based free form heading process improves the upset ratio up to 250 instead of 2.3 commonly achieved by conventional multistage upsetting processes. In this article, the second stage of the upsetting process is examined by investigating the deformation behavior of laser free formed austenitic chromium-nickel steel (1.4301) with a rod diameter of 0.5 mm and head diameters ranging from 1.1 mm to 2.1 mm, using a pneumatic forming machine. The experiments show that the maximum achievable true strain is much higher compared to a conve...

This paper presents a novel on-line monitoring technology to obtain forming quality in steel ball's forming process based on load signal analysis method, in order to reveal the bottom die's load characteristic in initial cold heading forging process of steel balls. A mechanical model of the cold header producing process is established and analyzed by using finite element method. The maximum cold heading force is calculated. The results prove that the monitoring on the cold heading process with upsetting force is reasonable and feasible. The forming defects are inflected on the three feature points of the bottom die signals, which are the initial point, infection point, and peak point. A novel PVDF piezoelectric force sensor which is simple on construction and convenient on installation is designed. The sensitivity of the PVDF force sensor is calculated. The characteristics of PVDF force sensor are analyzed by FEM. The PVDF piezoelectric force sensor is fabricated to acquire the actual load signals in the cold heading process, and calibrated by a special device. The measuring system of on-line monitoring is built. The characteristics of the actual signals recognized by learning and identification algorithm are in consistence with simulation results. Identification of actual signals shows that the timing difference values of all feature points for qualified products are not exceed ±6 ms, and amplitude difference values are less than ±3%. The calibration and application experiments show that PVDF force sensor has good static and dynamic performances, and is competent at dynamic measuring on upsetting force. It greatly improves automatic level and machining precision. Equipment capacity factor with damages identification method depends on grade of steel has been improved to 90%.

Optimizing consumptions in the field of civil construction led to define energy labels for residential buildings. To calculate the building energy demand the EPgl was determined, i.e. the annual consumption per m2 of primary energy. This paper examines the technical solutions useful to optimize the energy demands for heating during space-heating season and domestic hot water production (thanks to energy analysis softwares as MC11300 and TRNSYS) and, at the same time, to take into account the financial issues those interventions implied. The total inside heated surface of the building case study is 1204.00 m2, hence the inside heated volume is about 3250.80 m3. Besides the more traditional interventions concerning the building envelope and its systems, the paper examined the performance of a system obtained through the combination of a cogenerator (CHP) and a heat pump (HP), thus, substituting the conventional boilers of the buildings. CHP+HP solution increases the most the energy label of the building (from a D class with EPgl = 59.62 kW h m−2 year−1, to an A class, with EPgl = 25.64 kW h m−2 year−1), determining an annual energy cost saving of 3,114 € year−1, allowing to amortize installation costs (54,560 €) in a reasonable payback period, i.e. 15.4 years. This innovative solution in the residential sector can be realized through retrofit interventions on existing buildings, hence it leads the current dwelling towards nZEB with a remarkable benefits for the environment.