Evaluating the cutting rate (CR) of stones is important in the cost estimation and the planning of the stone processing plants. This research used regression models to estimate the stones’ CR based on their physico-mechanical characteristics. Stone processing factories in Mahallat City (Markazi province, Iran) were visited, and the CR of diamond circular saws was recorded on six different travertine stones. Next, the stone block samples were collected from the quarries for laboratory tests. Stones’ porosity (n), uniaxial compressive strength (UCS), and Schmidt hammer hardness (SH) were determined in the laboratory as their physico-mechanical characteristics. Correlation relationships of CR with physico-mechanical characteristics were evaluated using simple and multiple regression analyses, and estimator models were developed. Results showed that multiple regression models are more reliable than simple regression for estimating the stones’ CR. The validity of the developed multiple regression models was verified with the published data of one researcher. The findings indicated that these models are accurate enough for estimating the CR of stones. Consequently, the multiple regression models provide practical advantages for estimating the CR and save time and cost during the planning and design of the stone processing factories.

In end milling operation, cutting forces induce vibration on tool, work piece and clamping devices which affects surface integrity and quality of the product. In this process, to select the optimum end mill and machine tool, the prediction of exact cutting forces is of prime importance. In the present work, modeling and simulation of cutting forces in end milling operation are performed. Instantaneous chip geometry is predicted using a 3D simulation software, the effect of cutting depth and feed rate are calculated and cutting conditions are predicted before any machining operation.

Cutting forces that affects the cutting tool during machining are one of the important parameters must be known to select the economical cutting conditions and mount the workpiece on machine tools, securely. In this paper, the effects of the feed rate in machining of aluminum alloy 5083, used in lightweight structural application in automotive, shipbuilding and aerospace industries, on the cutting tool stresses have been investigated. Cutting forces were measured by a series of experimental measurements while stress distributions on the cutting tool were analyzed using a commercial finite element method (FEM) (ABAQUS). The results showed that the feed rate is the most relevant cutting parameter affecting cutting tool stresses.

Low cutting forces can signi cantly reduce the risk of damage to sensitive tissues adjacent to the bone. Because of its better control of the incision, lower cutting force and reduced postoperative complications, the application of ultrasonic tools in bone-cutting is of concern to surgeons. In this study, through the application of a full factorial design of experiments, the e ects of changes in cutting tool geometry, ultrasonic power, bone-cutting direction, and tool speed on the cutting forces of cortical bone are assessed simultaneously. The variance and regression of the experimental data are analyzed, and the impact of factors and interactions of the elements on the cutting forces are discussed. The adjusted coe cient of determination (R 2 adj) of the main cutting force and cutting resistance force of the statistical model were 91. 49% and 91. 15%, respectively. Both the blade geometry and ultrasonic power, together with their interactions, are the most in uential factors in the cutting forces, contributing 82. 2% and 86. 6%, respectively. The formation of teeth in the cutting edge improves the cutting process and reduces the cutting force by about 40%. To obtain high e ciency and low cutting force, it is recommended to use an ultrasonic-powered toothed edge blade with a pitch of 1 mm, a low vertical velocity, and a high longitudinal speed.

Background: The current study is to evaluate cardiovascular effects of anesthetic medications and volatile anesthetics on cardiac stress using cardiac stress index (CSI) and rate pressure product (RPP) and to determine which of them in useful in evaluating cardiac stress after comparing results obtained from each method.Materials and methods: 40 patients, 60-80 years old, who were all performed trans abdominal prostatectomy were studied. Patients were divided into two groups, half of patients were placed in group A and the other half in group B. The study was carried out as a blinded study. CSI was measured and evaluated in group A and RPP changes were studied in group B.Results: The mean CSI were 60.25±5.57, 63.05±5.54, 55.75±4.78 and 67.65±4.88 before anesthesia induction, after induction, before surgical incision and in recovery respectively. There was no meaningful difference.RPP mean in four above mentioned stages was 10.15±0.44, 9.9±0.69, 6.8±0.36 and 9.2±0.61 respectively. There was a meaningful difference between RPP in stages before anesthesia induction and before surgical incision (P<0.0001).Conclusion: Considering the obtained results from this study, it can be seen that even in noncardiac surgery, the stress level is high in patients in the stage before surgery. This figure was not clear in RPP index case and was not in accordance with CSI, which means CSI has been able to illustrate existing stress level better and efficiently.

Drilling and cutting stones as types of the engineering operations have encountered a lot of extensive and determining applications in different technical and engineering aspects of the mining. Estimating the drillability and cutability of stones by using drilling equipment and diamond wire saw have important roles in estimating the expenses and also designing mines. In this article some samples of carbonate ornamental stones from different mines in Iran have been studied in order to estimate and predict the drilling and also cutability rate. In order to evaluate the effect of the textural specifications on the rate of drilling and cutability, first a picture was provided from the thin microscopic surface of every stone sample and then the area, perimeter, diameter the longest diagonal and the shortest diagonal of the grains in the sections were determined and the other textural specifications were also determined through using mathematical relations and equations. After that the relationship between the abovementioned parameters with the drilling and cutting rate were determined by using univariate fitting. And finally to achieve more correlation coefficient multivariate fitting was applied for the data. Among the textural specifications affecting the drilling rate textural coefficient, the diameter of the grain, dequi, the ratio of the grain condition and the index of grain size homogeneity had a significant relationship with the drillability rate and also among those affecting the cutting rate, textural coefficient, the diameter of the grain, dequi, density, shape factor, index of interlocking, and the index of grain size homogeneity had significant relationships with the cutting rate and at the end the final equation to predicate the drillability and cutability was produced for these parameters.

The conventional material removal processes have always run into difficulties in machining hard materials, and nickel-based superalloys are no exception. The inherent properties of these materials usually lead to high tool wear rates and low surface integrity. These concerns justify the need for combining conventional material removal processes with advanced technologies. Laser Assisted Machining is one such process by which, through localized softening of work material prior to the cutting operation, a more efficient material removal process can be realized compared with what can be done by conventional machining. This work studies the effect of machining parameters such as constant Rotational speed at 400 RPM, feed rates of 0.035, 0.07, 0.105 mm/rev, and cutting depths of 0.3, 0.6, and 0.9 mm on variation of cutting force, chip temperature, surface roughness, and microhardness in variation of the workpiece surface. The process is a Laser Assisted Turning (LAT) process compared to conventional Turning (CT) by analyzing the parameters for a Waspaloy. A fiber laser with constant power output of 500 W was used to irradiate the tool material. The angle of contact of the beam with the tip of the tool was fixed at 60°. The workpiece's hardness was 385 ± 10 Vickers initially and had a diameter of 25 mm. It has been revealed that the application of LAT decreases the cutting force up to 16% compared to CT. The workpiece surfaces produced by LAT had higher chip temperatures than CT and were of 42% better quality in terms of surface roughness. In the LAT process, the difference in microhardness values at different points on the workpiece surface was within a much smaller range than in the CT process. The results showed that as the scanning speed of the laser increased on the surface of the workpiece, the thickness of the laser heat-affected zone below the surface of the workpiece decreased.

Since the cutting tools used in machining process of super alloys are subjected to high cutting forces, accordingly tools life is reduced, therefore improvement in alloys machining and reducing cutting forces to achieve longer tools life is an essential necessity. In this research, the effect of changes in feed rate on cutting forces in machining process of nickel based super alloys is investigated. Cutting tools used in this experiment was a tungsten carbide material, model 890, geometry square shaped and specification of SNMG 120412. Also the tools has been coated using physical vapor deposition by chemical composition of TiN/TiCN/AlTiSiN in both micro and nano layer conditions. According to the results, as the feed rate is increased cutting forces mostly increases in both micro and nano layer coating conditions.. Generally in this research, application of micro layer coating results in less cutting forces compared to nano layer coating, so it can be said that micro layer coating has a better performance.

AISI 4340 steel is a low alloy steel with high tensile strength that has numerous applications in industry. Machinability of this alloy steel is difficult due to its low heat conduction and high heat concentration in cutting zone. Therefore, use of cutting fluids in machining of this steel is inevitable. On the other hand, environmental problems of using mineral lubricants lead industries to use of biodegradable oils such as Vegetable-based cutting fluids. The aim of this study is to investigate the drilling of AISI4340 alloy steel in presence of semi-dry lubricant using soybean vegetable-based oil. For this purpose, drilling parameters including feed rate and cutting speed at three levels and workpiece hardness at two levels were chosen. Totally 18 experiments were carried out using coated carbide drill. Results revealed that vegetable-based oil can be used effectively in drilling using a semi-dry lubrication method. In addition, feed rate was the most effective parameter on cutting force and surface roughness and by increasing it, the cutting force increased, and the surface quality deteriorated. Also, workpiece hardness showed significant effect on surface roughness.