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The purpose of this multilevel shaft turning performance is to analyze the specimen used, namely medium carbon steel alloy and get good workpiece results, knowing the ductility of the workpiece by adjusting the tool blade, speed, time, depth of cut, and surface roughness. The research method used is the impact test method to see the results of the influence of strong currents in steel joints. The results of this study are cutting speed is very influential on the results of the surface roughness of the test material, can be seen from the data analysis and research results. The surface of the test material with the highest level of smoothness is obtained from the use of the lowest cutting speed (100 m/min) with a roughness level of (4.1). The highest roughness level (7.1) with the cutting speed used (200 m/min). The higher the cutting speed used, the greater the price of the surface roughness value obtained or produced. However, the wear of the tool blade used is likely to also affect the level of surface roughness. Geram income depends on the cutting speed, the greater the feeding motion used, the greater the thickness of the resulting geram. The smaller the cutting speed used, the smaller the resulting furrow. [ABSTRACT FROM AUTHOR]

A field experiment was carried out to evaluate the effect of leveling and tillage equipment on the soil bulk density and the growth and production of maize. Three landscaping types of equipment, namely laser, pelvic, and grader equipment, and three tillage equipment, namely moldboard plow, chisel plow, and no-till farming system. Soil bulk density, practical productivity, plant height, weight of 100 seeds, number of seeds per ear, and the yield of maize were measured. The results can be summarized as follows: The interaction between the pelvic leveling equipment and the no-till farming system was superior in obtaining the lowest soil bulk density, while the interaction between the laser leveling equipment and chisel plow was superior in obtaining the highest plant height, the highest weight of 100 seeds stood 36.70 g, the highest number Seeds per ear stood 371.30 seeds per ear and the highest yield of the plant stood 6.36 tons ha-1 compared to the other interventions. [ABSTRACT FROM AUTHOR]

This paper is concerned with the possibility of applying modern non-contact methods for assessing the wear as a result of tribological interaction between working bodies and the soil. An original method for wear testing using the test space discretization based on the 3D scanning technology was employed. A localized volumetric wear coefficient was proposed, allowing for wear analysis and improving the accuracy of the Holm-Archard model. The coefficient of local volumetric wear shows the influence of the nominal shape and the slip trajectory of the abrasive particle along the elementary surface on the intensity of wear. At local volumetric wear coefficient > 0.3, this factor determines the intensity of surface wear. Volumetric wear characteristics are the basis for prediction of wear consequences for different materials and techniques of reinforcement of working surfaces, subject to intensive wear in abrasive soil mass. The reliability of the study is confirmed by the comparison with the mass method for wear assessment and the results of the application of the proposed method for different conditions of abrasive wear of operating parts. [ABSTRACT FROM AUTHOR]

The article examines the development of woodworking industries in Kharkiv region, the situation of artisans, their income and everyday life. The impact of the new economic policy on production volumes is determined. Cooperage, carpentry, carpentry, and art products were studied. The transformation and development of handicrafts is identified and studied. The tax system that influenced woodworking handicraft production is considered. We made our own expedition to the workshop of a famous master who used the experience of his ancestors in the manufacture of products. The technology of production of wooden products characteristic of Kharkiv region is studied, and the industry concentration is determined. The connection of cooperage with other branches of agriculture is indicated. The authors studied the work of carpenters and described traditional housing of the hata-sena type and the gradual transformation in the Ukrainian village into a hata-sena-hata dwelling. We paid attention to the manufacture of tools (pitchforks, rakes), household items (troughs, mortars, ladles, buckets, etc.). The life of a rural family was directly connected with woodworking crafts, wood products were in demand, so the masters of this business increased significantly during the NEP period. The authors described the range of chiseled products, consisting of bowls, glasses, salt shakers, rolling pins. Birch, maple, hornbeam, and ash were used to make crafts. In the Slobozhansky Museum of local lore, at the exhibition "hall of ethnography", the authors studied wooden products and production technology of the period of the new economic policy in Kharkiv region. [ABSTRACT FROM AUTHOR]

Drilling two different materials in a layer, or stack-up, is being practiced widely in the aerospace industry to minimize critical dimension mismatch and error in the subsequent assembly process, but the compatibility of the drill to compensate the widely differing properties of composite is still a major challenge to the industry. In this paper, the effect of customized twist drill geometry and drilling parameters are being investigated based on the thrust force signature generated during the drilling of CFRP/Al7075-T6. Based on ANOVA, it is found that the maximum thrust force for both CFRP and Al7075-T6 are highly dependent on the feed rate. Through the analysis of maximum thrust force, supported by hole diameter error, hole surface roughness, and chip formation, it is found that the optimum tool parameters selection includes a helix angle of 30◦, primary clearance angle of 6 ◦, point angle of 130◦, chisel edge angle of 30◦, speed of 2600 rev/min and feed rate of 0.05 mm/rev. The optimum parameters obtained in this study are benchmarked against existing industry practice of the capability to produce higher hole quality and efficiency, which is set at 2600 rev/min for speed and 0.1 mm/rev for feed rate. [ABSTRACT FROM AUTHOR]

Fresh investigation carried out in the southern part of Bonaigarh subdivision of Sundargarh district, Odisha, brought to light some very significant dimensions of lithic celt production sites located in the village Sulabhdih and its surrounding region. Not only valley floors and foothills, but slope and top of hills were also utilized for mass production of semi-finished celts, particularly chisels and adzes. Our study suggests that mass production of these craft specialized semi-finished items were probably intended for not only local use at settlement areas where these were further modified into finished products, but these were presumably transported to different regions of highland Odisha and also beyond through trade and/or exchange network. Although no datable material could be recovered during our limited section scrapping, keeping in view available dates from within Odisha, Jharkhand and Karnataka, these sites are tentatively dated to the beginning of second millennium BCE. The present paper intends to bring out some new aspects of celt production in the southern part of Bonaigarh subdivision, hitherto unknown in Odisha and other parts of the sub-continent. [ABSTRACT FROM AUTHOR]

This paper takes Qingdao Jiaozhou Bay subsea tunnel project as the research object to study the relationship among rock mechanical parameters and chiseling specific energy and abrasion performance. SPSS22 was used to analyze the correlation between the parameters. The results show that except for the low correlation with Poisson ratio, all the other parameters in the single factor correlation analysis have high R. By taking the chiseling specific energy and abrasion performance as dependent variables, taking each mechanical parameter as an independent variable, multifactor regression analysis and stepwise multifactor fitting were carried out; it was concluded that the abrasion performance was highly correlated with uniaxial compressive strength and integrity coefficient, and the chiseling specific energy is highly correlated with uniaxial compressive strength and softening coefficient. In the process of verifying the fitting models, it is found that, under the influence of quartz vein and microfissure in the specimens, the chiseling specific energy formula has a higher fitting value, while the fitting formula of abrasion performance has a higher reference value for the specimens in the study area. [ABSTRACT FROM AUTHOR]

The northern Canadian Cordillera (NCC) of northwestern Canada is segmented by several margin-parallel, right-lateral, strike-slip faults that accumulated several hundred kilometers of displacement between the Late Cretaceous and the Eocene. The depth extent of these faults, notably the Tintina fault (TF), has important implications for the tectonic assemblage and evolution of NCC lithospheric mantle, but geophysical models and geochemical data remain inconclusive. Using a recent three-dimensional P-wave seismic velocity model, we resolved a series of sharp (-10 km) P-wave velocity contrasts (-4%) at uppermost mantle depths beneath the surface trace of the TF. Seismic anisotropy data that represent upper-mantle fabrics revealed similar changes in the orientation and magnitude of anisotropy in the vicinity of the TF. These data suggest that the TF is a lithospheric-scale shear zone. After restoration of 430 km of right-lateral displacement along the TF, fast P-wave anomalies align with the outline of the North American craton margin. We propose the fast anomaly structure currently located in eastern Alaska represents a fragment of the Mackenzie craton that was chiseled and displaced to the northwest by the TF between the Late Cretaceous and the Eocene. A second cratonic fragment currently located in the southern NCC may be associated with the Cassiar terrane at upper-mantle depth. These observations provide the first evidence that large lithospheric-scale shear zones cut through refractory mantle and produce major lateral displacement of cratonic mantle material within cordilleras worldwide. [ABSTRACT FROM AUTHOR]

Background: Laparoscopic pyloromyotomy has become a gold standard for the treatment of congenital hypertrophic pyloric stenosis (HPS). There have been recent reports on the use of transumbilical single-site laparoscopic surgery for congenital HPS; however, using transumbilical single-site laparoscopic surgery in pediatric cases is still controversial due to the difficulty with manipulation. In this study, some preliminary experience with the application of a novel transumbilical single-site laparoscopic approach in congenital HPS is described. Methods: A retrospective study was conducted involving 25 patients with congenital HPS treated in our hospital from August 2016 to August 2019. A pyloric electrocoagulation chisel combined with a left-handed main operation was completed in all of the patients and the operative times, postoperative length of stay, and operative complications were recorded. Results: The laparoscopic operation was completed in 25 patients with an average operative time of 21.9 ± 5.5 minutes, average postoperative length of stay of 2.5 ± 0.9 days, and no perforations of the pyloric mucosa, recurrent obstruction, surgical incision infections, and incision hernias. All of the patients had at least 3 months of follow-up, good growth and development, and the parents were satisfied with the postoperative scars. Conclusion: A pyloric electrocoagulation chisel combined with a left-handed main operation in the treatment of congenital HPS by a single-site umbilical laparoscopic pyloromyotomy is safe and effective, and can achieve a satisfactory cosmetic effect. [ABSTRACT FROM AUTHOR]

The paper presents the interaction system within soil working mechanical process, consisting of two elements, namely the soil and the tool metal, between which there is a relative movement at the level of the interface between the two elements. Research has shown that there are at least two main forces acting on the active parts: friction and impact, the action of these forces causing wear. In order to test the soil working knives under laboratory conditions, a test stand was used to test different types of soil working knives by modifying their functional parameters, respectively the working depth, knife angle relative to the soil, lateral angle relative to the forward direction, working speed and, if necessary, granulation and moisture of the test medium respectively. [ABSTRACT FROM AUTHOR]

On the soil chiseling, depending on the soil humidity, the volume occupied by the subsurface ridges reaches 60%. With a small amount of autumn rainfall in the South of Kazakhstan, which is 20% of the annual rate, the subsurface ridges are not completely destroyed by the beginning of spring field work. The presence of subsurface ridges with a soil density of 1.4 -1.6 g/cm³, worsens the quality of secondary tillage and inhibits the development of the root system of plants. A new working body for chisel rippers has been developed, which performs continuous loosening of the soil without leaving subsurface ridges. Its parameters are justified. Its laboratory tests were carried out in the layout with 3 and 5 bits, according to which the working body is operable. The study of soil profiles showed that the working body with 3 and 5 bits does not form subsurface ridges. The area of full volume loosening of the soil is approximately the same, is 100%. The traction resistance of the serial working body of the subsurface plow compared to the experimental working body with 3 bits at the same width of the cut was higher by 35-40%, respectively. An experimental working body with the following parameters was selected for the production of an experimental sample of the chisel deep ripper CR-2,4: the number of bits - 3; the angle of soil crumbling with a ploughshare - 12°; the height of the formation lifting - 55 mm; the length of bit - 165 mm. An experimental sample of the chisel ripper CR-2,4 was produced and its research tests were conducted, which showed that the tool was functional, the quality of tillage was satisfactory: the depth of tillage was stable, the volume of soil loosening was 100%, there were no subsurface ridges, and large clumps of soil were not carried out on its surface. [ABSTRACT FROM AUTHOR]

No-tillage system production in Argentina requires high traffic intensities, for example, 50 to 65 Mg km-1 ha-1. Due to these traffic intensities, continuously and successively applied, the soils are compacted. One of the frequently utilized techniques for management of topsoil and subsoil compaction is chiseling. The objectives of this work were: a) to evaluate the effect of vertical tillage on the physical properties of a Typic Argiudol soil from northeastern Rolling Pampa Region at Argentina and b) to quantify the power required by a chisel plow working in one and two depth levels on a soil under no-tillage. Three treatments were applied: T1) control plot (unloosened soil), T2) loosened with one chisel plow pass at a 0.25m deep range, and T3) loosened with two chisel passes, the first at 0.15m and the second at 0.25m. The following variables were measured: cone Index (CI), soil water content, (SWC), tractor slip (TS) and power and draft force (PD). The main results and conclusions showed: a) The CI values on the two deep tillage treatments were statistically different (P < 0.01) from that of the control plot, up to 300 mm and b) the chisel plow working in two depth ranges (T3) could significantly increase the specific resistance and drawbar power. This means that vertical tillage carried out in two chisel passes (T3) was, from an energy point of view, less efficient than one single pass (T2). [ABSTRACT FROM AUTHOR]

Aramid fiber–reinforced plastic (AFRP) composites have been widely used in automotive, aerospace, and defense industries. The common AFRP drilling process tends to cause damage to the composite structures which subsequently affects their fatigue lives and in-service performance. Understanding the mechanism of cutting force generation is crucial in controlling the cutting process for achieving desired hole quality and machining accuracy. This study proposes a novel mechanistic model considering both the cutting action and the extrusion action of the chisel edge. For the first time, the extrusion force generated by the chisel edge has been considered as a rigid wedge penetrating into an elastic half space based on the Hertz contact theory. The total thrust force in AFRP drilling is divided into three components: (i) thrust force generated by the cutting lips, (ii) thrust force generated by the chisel edge cutting action, and (iii) extrusion force generated by the chisel edge extrusion action. The proposed model was then validated by experiments and data was compared with the case where extrusion was not considered. The results show that our novel mechanistic model can provide a more accurate thrust force prediction. The average error of our model was 2.54% against the experimental data, whereas the error seen in conventional model without accounting extrusion was 8.22%. This suggests that the chisel edge extrusion plays a significant part in the drilling of AFRP and hence confirms the necessity of considering extrusion in establishing the associated mechanistic model. [ABSTRACT FROM AUTHOR]

The maximum fault strength and rate of interseismic fault strengthening ("healing") are of great interest to earthquake hazard assessment studies, as they directly relate to event magnitude and recurrence time. Previous laboratory studies have revealed two distinct frictional healing behaviors, referred to as Dieterich‐type and non‐Dieterich‐type healing. These are characterized by, respectively, log‐linear and power‐law increase in the strength change with time. To date, there is no physical explanation for the frictional behavior of fault gouges that unifies these seemingly inconsistent observations. Using a microphysical friction model previously developed for granular fault gouges, we investigate fault strengthening analytically and numerically under boundary conditions corresponding to laboratory slide‐hold‐slide tests. We find that both types of healing can be explained by considering the difference in grain contact creep rheology at short and long time scales. Under hydrothermal conditions favorable for pressure solution creep, healing exhibits a power‐law evolution with hold time, with an exponent of ~1/3, and an "apparent" cutoff time (α) of hundreds of seconds. Under room‐humidity conditions, where grain contact deformation exhibits only a weak strain‐rate dependence, the predicted healing also exhibits a power‐law dependence on hold time, but it can be approximated by a log‐linear relation with α of a few seconds. We derive analytical expressions for frictional healing parameters (i.e., healing rate, cutoff time, and maximum healing), of which the predictions are consistent with numerical implementation of the model. Finally, we apply the microphysical model to small fault patches on a natural carbonate fault and interpret the restrengthening during seismic cycles. Key Points: We unify two classes of frictional healing behavior with a microphysical modelWe derive analytical expressions for frictional healing parameters (healing rate, cutoff time, and maximum fault strengthening)We adopt the physically based model to simulate natural seismic cycle behavior [ABSTRACT FROM AUTHOR]

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The chisel-edge axial rake angle has an important effect on the processing performance of helical point micro-drills. In this research, the mathematical modeling for the spiral groove, helical flank, and cross-shaped chisel edge are conducted, and then three types of helical point micro-drills, each having a thinned chisel edge with an unequal axial rake angle, are designed and fabricated. Then, the finite element simulations and processing experiments of micro-drilling are performed separately, and the thrust force, torque, chip morphology, tool wear, and micro-hole machining quality are measured and evaluated. With the rise of the axial rake angle of the chisel edge, the curling degree of the chips and the thrust force were found to decrease owing to the increase of the rake angle along the inner cutting edge. The angle between the tool axis and chip axis was found to gradually decrease due to the reduction of the rake angle gradient along the cutting edge. Additionally, the thickness and width of the uncut chip of the inner cutting edge were found to increase, bringing about the rise in the torque. The wear degree of the micro-drills with a 0° axial rake angle (Type II) was the smallest due to their medium thrust force and torque, and a better micro-hole entrance morphology and minimum roundness were obtained. When drilling to the 30th hole, compared with the micro-drills with a − 10° axial rake angle (Type I) and 10° axial rake angle (Type III), the chisel edge maximum wear width of Type II (δ = 0°) was respectively reduced by 82.43% and 19.69%, and the micro-hole roundness respectively decreased by 26.7% and 11.33%. The thrust force of Type I (δ = − 10°) was the largest, so it caused greater tool wear and poorer micro-hole quality. The larger torque and lower rigidity of the inner cutting edge of Type III (δ = 10°) led to poorer drilling performance. Thus, helical point micro-drills having the 0° chisel edge axial rake angle are suitable for drilling 304 austenitic stainless steel. [ABSTRACT FROM AUTHOR]

Chip geometry can play a crucial role in understanding the rock cutting efficiency in mechanical excavation. In this study, the shape and size distribution of chips produced in laboratory scale rock cutting tests and their relationship with cutting geometry and rock cuttability were analyzed. For this purpose, a series of small-scale linear rock cutting tests (SSLRCT) were carried out with a simple chisel tool in unrelieved mode at cutting depth of 1, 2, 3, and 4 mm to determine the cuttability of four rock types (sandstone, marl, salt, and coal) and two synthetic (dental plaster and concrete) specimens. The size distribution of all cuttings collected from the grooves in different samples was determined by sieve analysis. The results were used to create a comprehensive particle size analysis, including a Rosin–Rammler plot (d′), coarseness index (CI), median (d50) and Krumbein mean particle size (dMPS). Also, the chips remained on the 4-mesh sieve and greater were chosen for chip shape analysis. The results obtained from chip analysis indicated that 85.6% of selected chips were fragmented in very platy and very bladed shape. Also, the analysis results showed that an inverse exponential correlation exists between specific energy and particle size indicators including CI, dMPS, d50, and d′ as anticipated based on rock fragmentation and grinding theories. Furthermore, a strong inverse correlation was found between specific energy and representative chip volume. The findings highlight the relationship of rock cutting efficiency with chip shape and size. [ABSTRACT FROM AUTHOR]

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In dentistry, chisel and mallet or dental bur has been used for various procedures since decades. Magnetic mallet (MM) is a dynamic, exclusive and patented device which makes use of electromagnetic impact, which allows a high - intensity and brief impact force to obtain plastic deformation of the bone. This avoids the applied forces influencing the whole of the craniofacial complex and has lot of advantages when compared to conventional chisel and mallet or bur used for bone cutting. Use of magnetic mallet prevents benign paroxysmal vertigo syndrome and reduces patient discomfort as well. It allows operator to use the handpiece of magnetic mallet with only one hand and the impulses are applied with a control pedal. It also allows better visibility of the operating field and control of the osteotome entry direction. Magnetic mallet can be also used for removal of crowns, bridges and implant components. This article emphasizes the advantages of magnetic mallet over conventionally used chisel and mallet in dentistry for various procedures. [ABSTRACT FROM AUTHOR]

Copyright of Revista del Museo de Antropología is the property of Museo de Antropologia - IDACOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article analyses ground stone discoveries from the late neolithic site of Pericei located in north-west of Romania, in Șimleu Depression. Combined characteristics of chisels and adzes in working process are discussed along with their context, especially those connected to stone working: the layer, dwellings and pebble agglomerations. We conclude that Pericei was a production center for stone chisels, appeared to supply the demand that until then was satisfied by Suplac/Porț site that continued to produce ground stone tools for a longer period.

The main purpose of this paper is to predict the rock cuttability by considering the peak cutting forces and analyze the shear behavior of chisel picks by numerical simulations on the basis of theoretical and numerical studies. Numerical modeling studies were carried out as two main parts using PFC3D. In the first part, triaxial compression test was modeled on soft and hard rocks at various confining stresses. In part two, a chisel pick was numerically simulated and advanced on artificially generated soft and hard rocks depending on different cutting parameters. Then, the variation of peak cutting forces with the rake angle and cutting depth was monitored by modeling unrelieved rock cutting tests. The simulation results were compared with the results of theoretical cutting mechanisms. In conclusion, it is found that reasonable relationships exist between two predictive methods. In addition, the effects of rake angles on the shear strength were analyzed using Nishimatsu's cutting model. The variation of shear angle during rock cutting was also examined. As a result of numerical studies, it is found that the theoretical formula proposed by Nishimatsu for the estimation of peak cutting forces and shear strength is mainly suitable in negative rake angles of chisel picks and in hard rocks. Furthermore, the shear planes of the microcracks in PFC3D were monitored and the shear angle was found to be ranging between 20° and 35°. These results were also verified by modeling of triaxial tests at different confining pressures. [ABSTRACT FROM AUTHOR]

When a cutter traverses a region local to the singularity in 5-axis machining, the stability of machine tool motion may be violated and inevitably lead to a reduction in machining quality and accuracy. In this paper, the underlying cause of the singular machine behaviors is first investigated by differentiating tool path motions, on the basis of the tool path motion expressions in part and machine coordinate systems. A further investigation indicates abrupt kinematic changes to be inevitable when the rotary axes approach a singularity. To eliminate such possible singular risks in 5-axis machining, a local tool path modification method is proposed by adjusting the two rotary axes out of a singular configuration. The critical kinematics smoothing and the consequent gouging concerns resulting from reorientation are comprehensively incorporated in the process of singularity avoidance, by means of a novel tool orientation optimization model. Specifically, the algorithm starts with the determination of an appropriate adjustment range in a simple yet effective manner, and then the primary rotary axis is adjusted in a constrained region away from zero, so as to avoid singularity. After that, the second rotary axis is accordingly adjusted, with no gouging requirements being violated. In this way, singularity problems in 5-axis machining are solved, and both the machine axes kinematics and surface gouging errors are under control. Machining simulation and laboratory experiments were conducted to validate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

A new design of the bottom unload non-bucket rotor (BUNBR) for an open-pit excavator with additional end chisels is described. It makes it possible not only to increase the output due to additional end chisels on the shell, but also to reduce the slope stress due to soil cutting from top to bottom on the working face and creation of a wider berm in comparison with the existing constructions of rotary working bodies. The method of calculation of soil cutting with the end chisel in the form of a two-sided skewed wedge is presented. Based on the spatial scheme of the cutting force components acting in the soil cutting, the expressions in coordinate axes for soil resistance to cutting with the end chisel were determined. These results were used to derive expressions for the tangential and end (lateral) cutting force exerted by a two-sided skewed wedge mounted at the BUNBR end side and to determine the total soil cutting force simultaneously exerted by the corner and end chisels. [ABSTRACT FROM AUTHOR]

Chisel edge thinning can effectively improve the drilling performance of austenitic stainless steel. Four kinds of helical point micro-drills, each with a thinned chisel edge of a distinct length, are fabricated based on the mathematics models of the micro-drill by using a six-axis computer numerical control tool grinder. Micro-drilling experiments on 304 stainless steel are conducted. Drilling performance is evaluated according to the measured and observed micro-hole machining quality, chip morphology, thrust force, and tool wear of the micro-drill tip. With a decrease in the chisel edge length, the micro-holes drilled using thinned micro-drills have small entrance burrs, roundness errors, and regular shapes, which are attributed to an increase in self-centering capability. Owing to increased equivalent chip thickness and different directions of chip flow, micro-drills with thinned chisel edge can generate more small-size chips and improve chip breaking. In addition, the inner cutting edge with a positive rake angle replaces the chisel edge with a negative rake angle to cut the workpiece, significantly reducing the chip curl, thrust force, and tool wear of micro-drills. However, helical point micro-drills with critical chisel edge lengths by thinning exhibit less thrust force and tool wear than do helical point micro-drills with no chisel edge because of the increase in the uncut chip width of the micro-drill. Thus, with the selected parameter range, the optimal helical point micro-drill is the micro-drill with a specific chisel edge length by thinning to improve drilling performance. [ABSTRACT FROM AUTHOR]

The flute shape to produce two new drill configurations are presented. The first configuration is to provide a straight diametral lip which could be extended to eliminate the chisel edge. The second configuration, which encompasses the feature of the first one at the inner portion of the lip and the curved shape at the outer portion of the drill lip, is provided to enhance the overall life of the drill. [ABSTRACT FROM AUTHOR]

A model of chip formation and an indentation model are constructed for the chisel edge region of a twist drill. From these models, predictions are made as to the shape of the wear zone about the chisel edge and equations derived for calculating the torque and thrust developed by the chisel edge given the geometry of the drill point, the cutting conditions and a shear stress factor for the work material.
Using the chisel edge thrust equation, it is shown that as the drill feed tends to zero, the drill thrust approaches a finite value the magnitude of which is in reasonable agreement with that observed experimentally. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a twist drill was used to drill carbon fiber reinforced polymer composite (CFRP) materials to study the influence of the chisel edge drilling behavior on delamination at different parameters. The test results show that a high spindle speed is beneficial to the chisel edge to remove the material when the chisel edge is about to drill the bottom of the plate, and the chisel edge drilling behavior has important effect on delamination. In order to reduce the impact of chisel edge on delamination, three kinds of step drills (different ratio of primary drill bit diameter to secondary drill bit diameter (k)) were designed to drill CFRP at different cutting parameters. The method of combining theory with practice is used to analyze delamination of step drill, and to optimize the step drill structure. Experimental results demonstrates that the hole entry quality of the step drills are better than that of the twist drill. k has great impacts on hole exit delamination. The step drill, k is about 0.5, can achieve the best hole exit quality under the large processing parameters, therefore it's suitable for drilling of CFRP. [ABSTRACT FROM AUTHOR]

Cross-shaped chisel edge thinning is an effective method to improve the drilling performance of non-coaxial helical flank micro-drill. In order to study the effect of the cross-shaped chisel edge on drilling performance, the mathematical model of cross-shaped chisel edge is proposed. The rake angle, lip inclination angle, uncut chip thickness, and uncut chip width are calculated by MATLAB software. Finite element models of four kinds of micro-drills with a different thinned chisel edge are established using DEFORM-3D software, and micro-drilling simulations on 304 austenitic stainless steel are carried out. The simulation results show that with a decrease in chisel edge length, the drilling force, tool temperature, tool wear, and curl degree of the chip are clearly reduced. However, for micro-drill without chisel edge, the torque and tool temperature are larger than other micro-drills, and string chips are generated during the drilling process. Furthermore, the non-coaxial helical flank micro-drill with an optimal cross-shaped chisel edge is manufactured by a six-axis CNC grinding machine, and the measurement results indicate that the geometrical parameters meet the designed values. At last, the micro-drill with an optimal cross-shaped chisel edge has a satisfactory drilling performance by the micro-drilling experiment. [ABSTRACT FROM AUTHOR]

To investigate the influence of foliation and structure within fault zones, synthetic fault gouges of quartz containing various thin layers of biotite were sheared in a triaxial testing system at hydrothermal conditions to acquire the faulting behaviour, along with quartz-biotite mixtures tested for comparison. First, in Series-1 experiments, gouges were sheared at a temperature of 100 °C, with effective confining pressure of 200 MPa, pore pressure of 30 MPa and loading rate of 1.22 μm/s. The results revealed that strength of quartz-biotite mixture weakened linearly with increasing biotite proportion, whereas the gouges with a biotite interlayer weakened much more significantly even for biotite content as little as ~5 wt%. Series-2 experiments were performed on simulated gouge with 15 wt% biotite interlayer at temperatures of 25–600 °C, effective normal stress of 200–230 MPa and pore pressure of 30 MPa, with stepped shear rates of 0.0488 to 1.22 μm/s. At effective normal stress of 200 MPa, the simulated foliate gouge showed a transition from velocity strengthening to velocity weakening around 200 °C, which persisted up to 600 °C. Stick-slips above 400 °C were associated with minor a – b averagely of ~−0.0006 and submicron d c values. At effective normal stress of 230 MPa and temperature of 600 °C, stick-slip motions evolved with slip distance to viscous-like behaviour at a displacement of ~3 mm. Microstructural observation on deformed samples revealed that shear deformation mainly occurred within the biotite interlayer in most cases, with surrounding quartz gouge only slightly deformed but increasingly compacted as temperature increased. Viscous-like behaviour corresponded to migration of dominant shear deformation to the quartz gouge, as indicated by the development of Riedel shears therein. Our results may help constrain fault strength and depth range of seismogenesis within fault zones associated with biotite in form of foliations and/or interconnected networks. [ABSTRACT FROM AUTHOR]

In the course of archaeological research at site 2 in Osłonki (Kuyavia, central Poland), a dense deposit of 20 cattle bones was discovered, most of which are semi-finished products for production of bone chisels. The collection was dated ab. 3350-3097 calBC. The traceological analysis of technological traces on the artefacts and experimental studies indicate that they were processed using several metal tools with working edges of varying shape, employed as chisels for bone splitting. Although SEM-EDX analyses did not show the presence of a substantial amount of copper on the surfaces of the artefacts, the collection can be considered most likely evidence for widespread use of this metal among Late Neolithic communities in Poland or at least the people who inhabited the area of Kuyavia. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the effect of textural properties of stones on cutting performance of a standard chisel tool. Therewithal, the relationships between textural properties and cutting performance parameters and physical and mechanical properties were statistically analyzed. For this purpose, physical and mechanical property tests and mineralogical and petrographic analyses were carried out on eighteen natural stone samples, which can be grouped into three fundamentally different geological origins, i.e., metamorphic, igneous, and sedimentary. Then, texture coefficient analyses were performed on the samples. To determine the cuttability of the stones; the samples were cut with a portable linear cutting machine using a standard chisel tool at different depths of cut in unrelieved (non-interactive) cutting mode. The average and maximum forces (normal and cutting) and specific energy were measured, and the obtained values were correlated with texture coefficient, packing weighting, and grain size. With reference to the relation between depth of cut and cutting performance of the chisel tool for three types of natural stone groups, specific energy decreases with increasing depth of cut, and cutting forces increase in proportion to the depth of cut. The same is observed for the relationship between packing weighting and both of specific energy and cutter forces. On the other hand, specific energy and the forces decrease while grain size increases. Based on the findings of the present study, texture coefficient has strong correlation with specific energy. Generally, the lower depth of cut values in cutting tests shows higher and more reliable correlations with texture coefficient than the increased depth of cut. The results of cutting tests show also that, at a lower depth of cut (less than 1.5 mm), even stronger correlations can be observed between texture coefficient and cutting performance. Experimental studies indicate that cutting performance of chisel tools can be predicted based on texture coefficients of the natural stones. [ABSTRACT FROM AUTHOR]

Scientists have dedicated many decades and resources to studying the effects of tillage on soil properties and crop yields. However, the literature lacks empirical data on corn/soybean yields and their stability to variable-weather years under long-term management at multiple locations in mid-Western USA. Thus, the objective of the current study was to evaluate yields and their stability from 2009 through 2013 at eight long-term sites with no-till (NT) and chisel-plow (CP) managed continuous corn (CC) and corn ( Zea mays )-soybean ( Glycine max ) rotations (C-s and c-S for corn and soybean phase). The tillage-treatment durations among the eight sites ranged from eight to 51 years in the Midwestern U.S. Corn Belt. The data indicates that tillage had no significant effect on long-term crop yields, with a few exceptions. During one site-year (southern Minnesota in 2012) in the CC system, NT yielded significantly 15.2% more than CP (9.1 vs. 7.9 Mg ha −1 ). However, CC yields averaged across sites were significantly 10.5 and 13.6% more in CP than NT in 2009 and 2010, respectively (12.6 vs. 11.4 Mg ha −1 in 2009; 12.5 vs. 11.0 Mg ha −1 in 2010). In the corn-soybean rotations, CP yielded significantly 18.7% more than NT (12.7 vs. 10.7 Mg ha −1 ) when averaged across years at one site in Iowa for the C-s phase. Yield stability indexes to environmental conditions indicated no differences in NT than CP yield stabilities among variable-weather years. However, NT had significantly lower range of relative yields across the variable-weather years as compared to CP for the CC system and C-s phase. These direct and synthesized data provide evidence of little to no differences between CP and NT managed corn/soybean research plots exist in the Midwestern US. Although CP may produce greater yields when averaged across the region’s research plots during some years, this effect was not evident at the individual research plot scale. [ABSTRACT FROM AUTHOR]

After the harvest of winter wheat, the tensile force, cross section of loosened soil and specific resistance of soil were measured on a loamy soil plot. During the comparative measurements, 3 blades were used with chisel width of 20 mm, 40 mm and 75 mm. In case of all blades, the measurements were carried out at the depth of 100, 200 and 300 mm. In the course of measurements, the standards of blades were attached in a measuring frame on six-component hinge with connected tensometric sensor. The selected blades were developed for a new type of tiller destined for primary cultivation of soil. Moreover, in case of a blade equipped by chisel there were used side wings of a width of 110, 150 and 200 mm for tillage into a depth of 100 mm. It was found that the width of blade chisels did not have a statistically significant effect on the values of specific resistance of soil during the soil tillage. At all widths of blade chisels, a trend of an increase in specific resistance of soil was recorded at growing recess into the soil. [ABSTRACT FROM AUTHOR]

This paper presents a cutter partition-based tool orientation optimization algorithm that can identify and eliminate both local and rear gouging in five-axis machining. This algorithm is developed to generate smooth gouge-free tool paths for arbitrary free-form surfaces machined by general Automatically Programmed Tools (APT) cutters. The algorithm involves an iterative process of cutter projection to compute the gouge-free cutter positions. During each iteration, the cutter partition method is used to classify the cutting portion of the cutter, which in turn determines the gouging condition. Based on the classification, the algorithm applies an optimal gouge-avoidance strategy to minimize the size of tool orientation and position changes. The proposed algorithm can handle the combination of local and rear gouging (either separately or simultaneously), guarantee front edge cutting (avoiding damage to the cutter and surface), ensure a safety clearance between the rear edge of the cutter and the machined surface, and achieve minimal interruption to tool orientation and position from gouge avoidance. Simulation and cutting experiments confirm the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Chisel plow is an important implement for primary tillage when the soil is dry and firm. In this research, fatigue life of a prototype of chisel plow arm under soil induced random excitation is analyzed. For this purpose, first, the field test is carried out on the chisel plow arm under soil-induced random excitations and operational modal analysis of the chisel plow arm is performed using stochastic subspace identification approach. In addition, a finite element model is constructed and successfully validated by stochastic subspace identification results. Then, the validated finite element model and power spectral density results of the measured random responses are used to achieve a process of the Mises stress in the arm needed for fatigue analysis. Finally, the fatigue life estimation of chisel plow arm is carried out in frequency domain using Wirsching-Light and Dirlik methods for different values of geometrical variables. The results of operational modal analysis demonstrate the possibility of identifying modal model of chisel plow arm in its operating condition on a basis of output-only data and the results of fatigue life estimation show that Wirsching-Light method provides a marginally safer prediction for chisel plow. [ABSTRACT FROM AUTHOR]

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Required draft force of chisel plow implement during tillage operations was comprehensively apprised. Field experiments were carried out at three levels of plowing depth (PD) (10, 20 and 30 (cm)) and three levels of forward speed (FS) (2, 4 and 6 (km/h)) in a clay loam soil. An intelligent model based on soft computing technique, adaptive neuro-fuzzy inference system (ANFIS), was used to integrally predict draft force. The FS and PD were chosen as input variables and the draft force was considered as output parameter in the first order Takagi-Sugeno-Kang type of ANFIS model. A comparison was also performed between results of the best developed ANFIS model and those of the well-known mathematical model suggested by American Society of Agricultural and Biological Engineers (ASABE). To select the best model with the highest predictive ability, some statistical performance criteria (SPC) (coefficient of determination (R 2 ), root mean square error (RMSE), mean relative deviation modulus (MRDM), mean of absolute values of prediction residual errors (MAVPRE) and prediction error mean (PEM)) were used. The results demonstrated that the best ANFIS model with acceptable SPC values of R 2 = 0.994, RMSE = 0.722 (kN), MRDM = 3.172%, MAVPRE = 0.561 (kN) and PEM = −0.071% was more accurate than the ASABE model. The ANFIS modeling results also showed that the simultaneous or individual increment of FS and PD resulted in nonlinear increment of draft force. Additionally, the interaction of FS and PD on draft force was congruent. Application of physical perception obtained from developed ANFIS model results led to exposition of a new scientific window towards deep root understanding of draft force behavior. Thus, it is practically proposed to employ the ANFIS model for proper selection of tractor type for pulling chisel plow implement in the most efficient manner. [ABSTRACT FROM AUTHOR]

A tool's axial rotation influences the geometric properties of a tool mark. The larger the axial rotation angle, the larger the compression of structural details like striations. This complicates comparing tool marks at different axial rotations. Using chisels, tool marks were made from 0° to 75° axial rotation and compared using an automated approach Baiker et al. [10]. In addition, a 3D topographic surface of a chisel was obtained to generate virtual tool marks and to test whether the axial rotation angle of a mark could be predicted. After examination of the tool mark and chisel data-sets it was observed that marks lose information with increasing rotation due to the change in relative distance between geometrical details on the tool and the disappearance of smaller details. The similarity and repeatability were high for comparisons between marks with no difference in axial rotation, but decreasing with increased rotation angle from 0° to 75°. With an increasing difference in the rotation angles, the tool marks had to be corrected to account for the different compression factors between them. For compression up to 7.5%, this was obtained automatically by the tool mark alignment method. For larger compression, manually re-sizing the marks to the uncompressed widths at 0° rotation before the alignment was found suitable for successfully comparing even large differences in axial rotation. The similarity and repeatability were decreasing however, with increasing degree of re-sizing. The quality was assessed by determining the similarity at different detail levels within a tool mark. With an axial rotation up to 75°, tool marks were found to reliably represent structural details down to 100μm. The similarity of structural details below 100μm was dependent on the angle, with the highest similarity at small rotation angles and the lowest similarity at large rotation angles. Filtering to remove the details below 100μm lead to consistently higher similarity between tool marks at all angles and allowed for a comparison of marks up to 75° axial rotation. Finally, generated virtual tool mark profiles with an axial rotation were compared to experimental tool marks. The similarity between virtual and experimental tool marks remained high up to 60° rotation after which it decreased due to the loss in quality in both marks. Predicting the rotation angle is possible under certain conditions up to 45° rotation with an accuracy of 2.667±0.577° rotation. [ABSTRACT FROM AUTHOR]