scholarly journals Minimizing tool vibrations when turning metals, as a method of energy-efficient cutting

2021 ◽  
Vol 279 ◽  
pp. 01007
Author(s):  
Viktor Lapshin ◽  
Denis Moiseev ◽  
Veronika Khristoforova
Keyword(s):  
Field Experiments ◽  
Consistent Model ◽  
Vibration Dynamics ◽  
Experimental Complex ◽  
Cutting Zone ◽  
Tool Vibrations ◽  
Metal Processing ◽  
Longitudinal Turning ◽  
The Relationship ◽  
Cutting System

Taking into account the interrelated vibration dynamics of cutting and the temperature in the cutting zone allows you to determine the most successful state or cutting mode in terms of energy costs. Purpose of the work: by forming a consistent model, determine the most convenient mechanism for the mode of operation of the cutting system, in which the further wear of the cutting wedge will be stabilized, the cutting force will also be stabilized, as well as the temperature in the cutting zone and the vibration of the tool. The paper examines: The process of metal processing by cutting on a lathe for the case of longitudinal turning of the product. Research methods: The research consists of a series of field experiments on real equipment using a modern measuring stand STD. 201-1, as well as using an experimental complex developed by us. Results and discussion. The results of processing experimental data, in particular, the results of measuring cutting forces, temperature and tool vibrations, are presented. The mechanism of stabilization of the processing process due to the relationship between temperature and vibrations during cutting and the formation of a quasi-stationary cutting mode is experimentally proved. It is assumed that due to the practical application of the results obtained in the work, it will be possible to increase the energy efficiency of metal processing by reducing the energy cost of vibration of the cutting wedge.

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
A.M. Zetty Akhtar ◽  
M.M. Rahman ◽  
K. Kadirgama ◽  
M.A. Maleque
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Base Fluid ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Cutting Zone ◽  
Observation Method ◽  
The Stability ◽  
The Relationship ◽  
Zeta Potential Analysis

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

Simulation on Extrusion Comminution Model of Roller Press

2010 ◽  
Vol 156-157 ◽  
pp. 1702-1707
Author(s):  
Xiang Wen Cheng ◽  
Jinchao Liu ◽  
Qi Zhi Ding ◽  
Li Ming Song ◽  
Zhan Lin Wang
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Field Experiments ◽  
Size Ratio ◽  
Optimum Operating ◽  
Extrusion Force ◽  
Particle Size Ratio ◽  
Small Constant ◽  
Working Parameters ◽  
The Relationship

How to predict the relationship among particle size and among product size, to establish the relationship between the granularity and working parameters in the process of grinding and to determine the optimum operating parameters. With proposing BS squeeze crush model by L. Bass and the idea of roll surface division as the material uneven extrusion force are adopted. Based on field experiments the experimental data is analyzed, the select function and the breakage functions are fitted with MATLAB software, and obtaining their model. The comminution model is determined by the roller division. We obtain the model parameter through the experimental data. Through model analysis shows: the relationship between particle breakage and energy absorption, namely the smaller size of the same power, the lower broken; the breakage diminishes with the decrease of particle size ratio and it will be tending to a small constant when the smaller particle size ratio. The breakage functions rapidly decrease within ratio of between 0.2-0.7. This shows: the energy consumption will rapidly increase when the particle size of less than 0.2 in broken; the selection diminish with the decrease of particle size. Pressure (8-9MPa) should be the most appropriate value.

scholarly journals Water lubrication of graphene oxide-based materials

Friction ◽  
2021 ◽  
Author(s):  
Shaoqing Xue ◽  
Hanglin Li ◽  
Yumei Guo ◽  
Baohua Zhang ◽  
Jiusheng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Lubrication Theory ◽  
Lubricant Additives ◽  
Water Lubrication ◽  
Broad Application ◽  
Water Dispersibility ◽  
Metal Processing ◽  
The Relationship ◽  
Ph Concentration

AbstractWater is as an economic, eco-friendly, and efficient lubricant that has gained widespread attention for manufacturing. Using graphene oxide (GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties, water dispersibility, and broad application scenarios. In this review, we offer a brief introduction about the background of water lubrication and GO. Subsequently, the synthesis, structure, and lubrication theory of GO are analyzed. Particular attention is focused on the relationship between pH, concentration, and lubrication efficacy when discussing the tribology behaviors of pristine GO. By compounding or reacting GO with various modifiers, amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios. These various strategies of GO-composite generate interesting effects on the tribology behaviors. Several application cases of GO-based materials are described in water lubrication, including metal processing and bio-lubrication. The advantages and drawbacks of GO-composites are then discussed. The development of GO-based materials for water lubrication is described including some challenges.

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

Synergetic Concept of Software Control of Machining Processes on Metal-Cutting Machines

2021 ◽  
pp. 24-36
Author(s):  
V.L. Zakovorotny ◽  
V.E. Gvindzhiliya
Keyword(s):  
Tool Wear ◽  
Metal Cutting ◽  
Wear Testing ◽  
External Control ◽  
Machining Processes ◽  
Cutting Zone ◽  
Output Characteristics ◽  
The Cost ◽  
And Control ◽  
Cutting System

High precision metal-cutting machines ensure that the programmed machine actuator trajectories correspond to the real ones. For lathes these are the trajectories of the longitudinal and transverse calipers of the system, as well as the spindle. The purpose of processing is to produce parts of a given quality while minimizing the manufacturing costs. The condition of the dynamic cutting system, determined by the trajectories of forces and deformations, affects the quality indicators of parts and the cutting efficiency, which depends on the intensity of tool wear. The properties of the system change depending on the phase trajectory of the power of irreversible transformations of the energy supplied to the cutting zone by the work performed. Their changes related with the evolution of the parameters of the dynamic link formed by cutting are manifested in the development of tool wear and changes in the quality of the part. Thus, the power of irreversible energy transformations is one of the internal factors causing changes in the output characteristics of processing and the state of the process. In this regard, when processing on machine tools, there is a problem of synergistic coordination of external control (for example, the CNC program) with internal one, the source of which is the irreversible transformation of the energy supplied to the cutting zone. The article considers the problem of synergetic coordination of external and internal controls during cutting process, the solution of which will allow increasing the efficiency of processing on CNC machines. A mathematical model of a controlled dynamic cutting system and control algorithms are proposed to improve the efficiency of processing parts of a given quality while minimizing the intensity of tool wear. Testing of the developed algorithms has shown that their use reduces the cost of manufacturing parts by 1.2.

scholarly journals Nitrogen management in wheat based on the normalized difference vegetation index (NDVI)

2018 ◽  
Vol 48 (9) ◽  
Author(s):  
André Luis Vian ◽  
Christian Bredemeier ◽  
Marcos Alexandre Turra ◽  
Cecília Paz da Silva Giordano ◽  
Elizandro Fochesatto ◽  
...  
Keyword(s):  
Technical Efficiency ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Field Experiments ◽  
Shoot Biomass ◽  
Sensor Field ◽  
N Dose ◽  
Plant Emergence ◽  
The Moment ◽  
The Relationship

ABSTRACT: Biomass production and nitrogen (N) accumulated in wheat shoots may be used for quantifying optimal topdressing nitrogen doses. The objective of this study was to develop and validate models for estimating the amount of biomass and nitrogen accumulated in shoots and the N topdressing dose of maximum technical efficiency in wheat using the normalized difference vegetation index (NDVI) measured by an active optical canopy sensor. Field experiments were carried out in two years and treatments consisted of N doses applied at plant emergence and as topdressing. NDVI, shoot biomass and N accumulated in shoots at the growth stage of six fully expanded leaves and grain yield were evaluated, being determined the topdressing N dose of maximum technical efficiency (DMTE). The NDVI was positively correlated to shoot biomass and N content in shoots and models for the relationship between these variables were developed and validated. The DMTE was negatively correlated with the NDVI value evaluated at the moment of N topdressing application. Thus, NDVI evaluation by an active optical canopy sensor can be used for nitrogen fertilization in variable rate, allowing the adjustment of applied N doses in different areas within a field.

No-till alfalfa stand termination strategies: Alfalfa control and wheat and barley production

1999 ◽  
Vol 79 (1) ◽  
pp. 71-83 ◽  
Author(s):  
W. J. Bullied ◽  
M. H. Entz ◽  
S. R. Smith Jr.
Keyword(s):  
Field Experiments ◽  
Treatment Method ◽  
Triticum Aestivum L ◽  
Hordeum Vulgare L ◽  
Unique Problem ◽  
Crown Area ◽  
No Till ◽  
Cereal Grain ◽  
Medicago Sativa L ◽  
The Relationship

Crop rotations involving perennial alfalfa (Medicago sativa L.) present the unique problem of terminating the alfalfa stand. Intensive tillage currently used to terminate alfalfa increases the risk of soil erosion and reduces many of the rotational benefits from alfalfa. Inadequate alfalfa termination results in severe competition to the following crop by surviving alfalfa plants. Field experiments were conducted in Manitoba between 1991 and 1993 with the following objectives: 1) to investigate no-till vs. tillage management systems for successful alfalfa termination, 2) to compare fall vs. spring alfalfa termination, 3) to compare the performance of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) seeded into alfalfa residue, and 4) to determine the relationship between alfalfa escapes and grain yield. Fall termination produced higher grain yields than spring termination, however this advantage was only achieved with the better termination treatments capable of lowering alfalfa regrowth below a critical level. The best herbicide treatment tested here was glyphosate at 1.78 kg a.i. ha−1. Successful treatments would have to reduce residual alfalfa basal crown area (a measure of alfalfa regrowth potential) after cereal grain harvest to below 2%. Alfalfa escapes reduced yield of following wheat and barley crops similarly (P > 0.05). When alfalfa termination treatment method allowed some regrowth, in-crop herbicide treatments significantly reduced alfalfa basal crown area. Results of this study indicate that it is feasible to terminate alfalfa with herbicides in the absence of tillage, however an overall cropping strategy, including adequate consideration of weeds present in alfalfa fields at time of termination, must be considered. Key words: Herbicides, competition, recropping, no-till, alfalfa regrowth, soil conservation, sustainable cropping

Analysis of Chatter Vibration Through Step-Function Response

1972 ◽  
Vol 94 (4) ◽  
pp. 985-990
Author(s):  
H. Takeyama ◽  
O. Sakata
Keyword(s):  
Machine Tool ◽  
Step Function ◽  
Response Analysis ◽  
Chatter Vibration ◽  
First Approximation ◽  
Machine Tool Structure ◽  
On Line ◽  
Cutting Zone ◽  
Simple Evaluation ◽  
Cutting System

This paper deals with a challenge to apply the method of indicial response analysis for obtaining the frequency characteristics of total cutting system, tool system, and cutting zone. The feasibility of this method has been verified by simulation tests. Furthermore, linearity in cutting zone has been demonstrated to a first approximation by utilizing the proposed method. As examples of its application, on-line prediction or prevention of chatter vibration and simple evaluation of machine tool structure have been proposed.

Factors influencing herbicide efficacy when removing lucerne prior to cropping

2006 ◽  
Vol 46 (10) ◽  
pp. 1301 ◽  
Author(s):  
S. L. Davies ◽  
A. M. Storrie ◽  
A. S. Cook ◽  
R. A. Latta ◽  
A. D. Swan ◽  
...  
Keyword(s):  
Field Experiments ◽  
New South ◽  
Residual Activity ◽  
Management Guidelines ◽  
Herbicide Treatment ◽  
South Wales ◽  
Root Reserves ◽  
Herbicide Mixtures ◽  
The Impact ◽  
The Relationship

Farmers often experience inconsistent responses when using herbicides to terminate an established lucerne pasture prior to cropping. In an attempt to redress this problem, a series of field experiments were conducted between 1999 and 2002 at various locations in southern and northern New South Wales, the Australian Capital Territory, and south Western Australia that aimed to identify management guidelines that improved the efficacy of herbicide mixtures commonly used to remove lucerne. Collectively, these studies indicated that herbicides were generally less effective when applied either early (less than 2 weeks) or late (6 weeks or more) in the regrowth cycle of lucerne after defoliation. Herbicide efficacy tended to be greatest if applied to regrowth 3–5 weeks after defoliation, which corresponds to a time when the lucerne crown and root reserves are likely to be in the process of being replenished by photoassimilates transported from the shoot. The impact of timing of herbicide application in relation to season was compared at a number of locations. Across all the sites and years, spring herbicide applications were generally the most effective, removing on average 87% of the lucerne (range 53–100%) compared with 72% in summer (24–100%) and 60% in autumn (7–92%). Spring applications were also more consistent in their effect, removing >80% of the lucerne plants in 9 out of 12 experiments, whereas similar rates of removal occurred on 4 occasions in 9 summer applications and only twice in 8 autumn applications. Some of the seasonal variation could be explained by differences in the amount of rainfall prior to herbicide applications. It was assumed that the relationship between rainfall and herbicide efficacy reflected the stimulation of lucerne shoot and root growth by the additional soil moisture before herbicide treatment. Herbicide mixtures that contained ingredients such as picloram that retain residual activity in the soil tended to be more effective and were less influenced by lucerne growth and season than those herbicides with little or no residual activity. However, such chemicals could potentially restrict which crops can subsequently be grown after a lucerne pasture has been removed. It was concluded that >80% of lucerne plants were likely to be removed using herbicides provided that the herbicide treatment was applied to actively growing lucerne 3–5 weeks after defoliation, and when greater than 70–95 mm rain had fallen in the 6–8 weeks prior to application.

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