Thermal necrosis following bone drilling is a serious threat to orthopedic surgeries as it can cause irreversible damage to bone cells and failure of fracture treatment. Part of the bone temperature rise is due to chip formation while the other part is related to the heat sources of drill bit-hole wall friction as well as chip-hole wall friction. The present study has examined reduction of frictional heating by changing the drill bit design. Drilling tests were performed on 31 states of drill bits with different designs under conditions of rotational speed of 1000 rpm, feed rate of 50 mm/min, and hole depth of 8 mm on the bovine femur. The change in the diameter and length of the different sections of the drill bit had a significant influence on the bone temperature rise; in 21 cases it led to a reduction, while in 6 cases it resulted in an increase in the temperature compared to the result of the standard drill (Tm = 24 °C). Further, using statistical analysis through Minitab software, a statistical model of bone temperature rise was developed based on the drill geometry and optimal values for the drill bit geometry were extracted. The validation test performed on the optimal drill bit revealed an acceptable agreement of its result (Tm = 8.6 °C) with the value predicted by statistical analysis (Tm = 8.8 °C) as well as the possibility of preventing thermal necrosis by applying this new design for the drill bit, compared with other methods of drilling.

This study explored the effect of multiple recycling on the dimensional stability of wood-plastic composite. For this purpose, the injection moulding parameters effective on dimensional stability were first optimized based on the response surface method. Optical scanning, melt flow index (MFI), and differential scanning calorimetry (DSC) tests were used to analyse the shrinkage and deformation of recycled samples. The obtained results revealed that some recycled samples were subjected to thermal changes during the grinding and injection moulding process. The MFI and DSC results showed that the high-density polyethylene thermoplastic used in the wood-plastic composite was broken with long chains. Also, thermal changes occurred during the grinding and injection moulding process. The samples recycled three times had the highest dimensional instability (2.8% of shrinkage values). Finally, with the reduction of DSC, the semi-crystalline structure changed to amorphous, and the samples recycled four and five times had 2.7% and 2.5% shrinkage percentage, respectively.

Environmental side effects of machining lubricants are the main reasons for the progressive development of utilizing the minimum quantity lubrication (MQL) method instead of conventional methods. Owing to the high specific energy of cutting and generation of more heat in grinding, the MQL technique has a lower efficiency than conventional methods. However, by adding nanoparticles to the base oil, the lubrication efficiency in grinding can be enhanced. In this research, grinding of cold work tool steel AISI D2 was studied using a MQL technique by adding MoS2 and CuO nanoparticles to two types of vegetable-based oils: colza and soybean with different concentration percentages, and their effects were examined on the cutting forces (normal and tangential forces) and surface roughness. The results indicated that the values of normal force and tangential forces diminished by 19 and 35 % when using CuO nano powder in soybean base oil with a concentration of 4 % and MoS2 nano powder in soybean base oil with a concentration of 2 %, respectively. Furthermore, when using CuO nano powder in colza base oil and with a concentration of 2 %, the surface roughness had a significant reduction of 77 % in comparison with pure oil as a grinding fluid.

One of the main challenges in skull base tumor removal is to mitigate thermal damages that occur in response to grinding the skull bone. During this process, temperature rise occurs at the site of bone grinding, and may cause irreversible thermal damage to the bone, nerves, and arteries. This research aimed to study temperature variations during high-speed grinding of the bone via infrared thermography to determine the threshold of the high-speed cutting range (HSC-range) for achieving the minimum temperature rise and minimizing the resulting thermal damages. Experimental tests have been performed in 75 states using the parameters of cutting speed (25 states) and feed rate (3 states) on bovine femur samples. The temperature changes of bone have been measured through infrared thermography. The results indicated that temperature rise had a direct relationship with the tool feed rate. Furthermore, the cutting speed of 250 m min−1 at different feed rates was the HSC-range threshold, after which a descending trend of temperature rise emerged; each led to the minimum temperature rise and beyond HSC-range, the temperature rise found an ascending trend. In order to reduce the thermal damage in neurosurgical bone grinding, the following parameters are suggested as follows: cutting speed 350–425 m min−1 and for the feed rate 20 mm min−1 (ΔT = 4.8–8.5 °C ); cutting speed 500–550 m min−1 and for the feed rate 30 mm min−1 (ΔT = 7.2–9.3 °C), and cutting speed 650–675 m min−1 and for the feed rate 40 mm min−1 (ΔT = 10–12.5 °C).

Evaluation the effect of adding CNT and CuO to the base fluid on the health and surface roughness of Inconel 718 MQL grinding

Abstract One of the main challenges in skull base tumor removal is the thermal damages that occur in response to grinding the skull bone. During this process, temperature rise occurs at the site of bone grinding, and may cause irreversible thermal damage to the bone, nerves, and arteries. The aim of the present research is to study temperature changes during high-speed grinding of bone via infrared thermography to determine the threshold of high-speed cutting range (HSC-range) in order to achieve the minimum temperature rise and minimize the resulting thermal damages. Experimental tests have been performed in 75 states using the parameters of cutting speed (25 states) and feed rate (3 states) on bovine femur samples. The temperature changes of bone have been measured through infrared thermography. The results indicated that temperature rise had a direct relationship with the tool feed rate. Further, the cutting speed of 250 m.min− 1 at different feed rates was the HSC-range threshold, after which a descending trend of temperature rise emerged; each led to the minimum temperature rise and beyond HSC-range, the temperature rise found an ascending trend. Thus, in order to reduce the thermal damage in neurosurgical bone grinding, the following parameters are suggested as follows: cutting speed 350–425 m.min− 1 for the feed rate 20 mm.min− 1 (ΔT = 4.8–8.5°C ); cutting speed 500–550 m.min− 1 for the feed rate 30 mm.min− 1 (ΔT = 7.2–9.3°C), and cutting speed 650–675 m.min− 1 for the feed rate 40 mm.min− 1 (ΔT = 10-12.5°C).

Heat generation during bone cutting by sagittal saw may lead to temperature rise and possible incidence of thermal necrosis. The aim of the present research is to examine the effect of saw blade oscillation rate, blade feed rate, and irrigation by physiological saline solution on the bone temperature rise during sawing in order to determine the desired conditions for reducing the extent of thermal damage. For this purpose, empirical tests of bovine femur cutting were performed in 15 states, including five levels for the blade oscillation rate (10,000–18,000 cpm with 2000 cpm intervals) and three levels for the feed rate (10–30 mm.min −1 with 10 mm.min −1 intervals) for dry conditions; and five states, including five levels for the blade oscillation rate (10,000–18,000 cpm with 2000 cpm intervals) and one level in feed rate of 20 mm.min −1 for the irrigation conditions. The results indicated that the bone temperature rise had a direct relationship with the blade oscillation rate and an inverse relationship with its feed rate. In the state of no cooling, the minimum temperature rise (Δ T = 65.45°C) occurred at the blade speed of 10,000 cpm and feed rate of 30 mm.min −1 , while in the state of sawing with irrigation, the temperature rise almost did not exceed the allowable range (Δ T ≤ 10°C). The results suggested that to lower the possibility of incidence of osteonecrosis in the bone resection by sagittal saw, cooling with physiological saline solution or application of the minimum blade oscillation rate and maximum feed rate is recommended.

In complex fractures of bone, to immobilize the fracture location, internal and external immobilization tools and equipment are used. For connecting immobilizing equipment, drilling into bone should be done. During this operation, the forces required for plastic deformation of bone and chip formation, as well as friction factor cause elevation of temperature at the drilling site. If the temperature rise exceeds 47 °C, it results in thermal necrosis in the bone. Thermal necrosis causes failure in immobilization and in turn improper fracture treatment in the desired direction and angle. In the current study, attempts have been made to detect changes in the temperature of bone and drill bit during drilling process using infrared thermography. Drilling tests have been performed on bone samples of bovine femur and the thermal changes of the bone and drilling bit have been measured. Based on the results of the statistical analysis, it was found that the temperature rise of the drill bit was directly related to the feed rate, while the bone temperature rise was inversely associated with the rotational speed and feed rate. Also, the experimental results indicated that at the feed rate of 50 mm min−1, the only allowable speed for drilling has been 1500 r min−1 and at feed rates of 100 and 150 mm min−1, application of speeds of 2000–3000 r min−1 can be useful to prevent thermal necrosis. Infrared thermography is capable of determining bone and drill bit temperature changes during the drilling, so it can be used to study temperature in order to prevent of thermal necrosis.

Bone drilling process is one of the essential steps in orthopedic surgeries. If temperature of this process is more than 47 ° C, thermal necrosis occurs. In the event of the thermal necrosis, bone consolidation is not well done. For this reason, a lot of research has been done to reduce the thermal necrosis. In this study, by using an analytical model, bone temperature elevation during drilling was investigated at different feed rates and rotational speeds. To validate the analytical results, the bone temperature elevations were evaluated by comparison with bone drilling process using bovine femurs. With comparison the results, it was found that there are differences between analytical and experimental results that are related to incorrect estimation of the fraction of total heat generated that flows into the bone. Therefore, the correct values of this fraction were obtained after comparing analytical and experimental results. Finally, it was concluded that the fraction is dependent on the feed rate and rotational speed, and also a new equation was presented for it. Experimental results show that within the range of the investigated variables, increase in feed rate causes decrease in bone temperature and with the increase in rotational speed, the bone temperature changes are swinging.

Medical insoles play a significant role in pressure reduction, proper stress-strain distribution, and correcting some deformities in the foot. The aim of the present research is to design and fabricate new medical insoles with universal fluid layer. After fabricating two types of insoles including flat silicone insole with shore 17 and flat silicone insole with universal fluid layer (medical silicone with shore 17 and silicone gel with shore 0), PEDAR test using one person in two standing and walking positions in three conditions comprised without the use of medical insole, using of flat medical silicone insole, and flat silicone insole with universal fluid layer was performed. These insoles were also modeled and solved in Abacus software according to the results obtained from mechanical properties testing of silicone and PEDAR test. The results of the finite element analysis showed that absorption of stress and strain in the static state by the silicone insoles with universal fluid layer was 63% and 63%, and in the dynamic state was 84% and 89% more than those obtained by the flat silicone insoles, respectively. The experimental results of the PEDAR system also showed that in the standing state, the silicone insoles with universal fluid layer and the flat silicone insoles had 58% and 30% pressure reduction, respectively, in comparison with without insole condition. Also, in the gait state, the silicone insoles with fluid layer and the flat silicone insole showed 37% and 9% pressure reduction, respectively, in comparison with without insole condition. Eventually, it was found out that the silicone insoles with fluid layer reduce plantar pressure well in comparison to the flat silicone insoles.

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: A. Mossayebi, E. Shakouri, B. Manafi, Numerical and Experimental Investigation of Performance of Styrene Butadiene Rubber, Polyurethane, and Polyvinyl chloride in Outsoles Fabrication, Iranian Journal of Manufacturing Engineering, Vol. 7, No. 6, pp. 5664, 2020 (in Persian) یسررب یبرجت و يددع درکلمع داوم نریاتسا کیتسلا یلپ ،نیداتوب یلپ و ناتروا لینیو دیارلک رد تخاس هریز شفک ي

Article Type Original Research Authors Hoseinpour H.1 MSc, Saraeian P.*2 PhD, Shakouri E.1 PhD

Heat generation during bone drilling operations is a serious challenge for the internal fixation surgery of bone fracture. Indeed, the heat generated at the drilling site causes complications including local temperature rise, thermal necrosis, irreversible damages to the bone tissue, and possible failure of orthopedic surgery. High-speed machining is an advanced method which has achieved remarkable results in some cases of reducing the temperature rise of the tool or workpiece. The present research examines high-speed drilling (HSD) of the bone using theoretical (based on Orthogonal Cutting theory and High-Speed Cutting model) and experimental (based on infrared thermography) approaches. The thrust force and temperature changes of the bone and drill bit have been measured at different rotational speeds. The drilling tests have been performed under a constant feed rate of 100 mm min−1, hole depth of 8 mm, and 18 rotational speeds of 1000–18,000 r min−1 (with 1000 r min−1 intervals) on a bovine femur. The results indicated that application of high rotational speeds in most cases caused increased temperature rise of the bone; only the rotational speed of 7000 r min−1 (which is associated with dramatic force reduction) and speed of 11,000 r min−1 (which is associated with alteration of the chip formation mechanism and its nature) resulted in the minimum extent of temperature rise in the bone. It was also observed that the High-Speed Cutting model was able to correctly estimate the threshold of high-speed machining range for the bone (5000 r min−1) and was also valid for the bone drilling operation.

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا يارب : Please cite this article using: Y. Mirzaloo, P. Saraeian, E. Shakouri, M. Najafi, Experimental investigation on the effect of thickness, heating time and extrude direction on thermal shrinkage and thickness variations ABS sheet in vacuum forming process, Iranian Journal of Manufacturing Engineering, Vol. 7, No. 8, pp. 19, 2020 (in Persian) یسررب یبرجت ریثأت تماخض رب دورتسکا تهج و یهد ترارح نامز ، و یترارح ضابقنا تماخض تارییغت قرو ABS رد دنیارف گنیمرف مویکو

The performance of airbag and its deployment are based on a fast exothermic-chemical reaction. The hot gas resulting from the chemical reaction which results in airbag deployment can cause thermal damage and skin burning for the car passenger. The thermal burns due to airbags are of two types: burns due to direct contact with the airbag surface and burns resulting from exposure to the hot gas leaving the deflation vents of the airbag. In this research, for experimental study of the burns resulting from exposure of the skin to airbag, using infrared thermography, the extent of temperature rise of the airbag surface was detected and measured from the zero moment of its inflation. Next, using Henriques equation, the extent of thermal damage caused by airbag deployment and its resulting burn degree was calculated. The results indicated that during the inflation of airbag, the maximum temperature of its surface can be 92 °C ± 2 °C. Furthermore, if the vehicle's safety system functions within the predicted time intervals, the risk of thermal damage is virtually zero. However, if even a slight delay occurs in detachment of the passenger's head and face off the airbag, second- and third-degree burns could develop.

For skull base tumor removal neurosurgery, skull bone grinding is required. During this process, temperature rise occurs, which may result in an irrecoverable thermal damage. In the present research, temperature variations during bone grinding have been studied. Experimental tests have been conducted in 27 states in terms of the parameters of rotational speed (three states), feed rate (three states), and cutting depth (three states) on bovine femur bone samples. Attempts have been made to determine optimal processing conditions for minimizing thermal damage during the surgery through infrared thermography and measuring thermal variations of the bone. The results indicated that the temperature rise of the bone has a direct relationship with the parameters of rotational speed, feed rate, and cutting depth. In other words, with elevation of each of these parameters, temperature rise was also intensified. Out of the cutting parameters, rotational speed had the maximum impact on temperature rise, followed by cutting depth and feed rate. Therefore, to reduce the extent of thermal damage incurred to the neural tissue, the minimum values for the cutting parameters are proposed as follows: rotational speed = 45000 r min(-1), feed rate = 20-30 mm min(-1) with depth of cut = 0.25 mm, and feed rate = 20 mm min(-1) with cutting depth = 0.50 mm.

Medical insoles and orthopedic shoes are responsible for reducing the force exerted by the ground to the plantar region of the feet. This combination is designed to develop a suitable distribution of stress and strain in the plantar region. In the present study, attempts have been made to design a prototype of medical footwear which can provide a proper stress and strain distribution in the plantar region while reducing pressure in comparison with current orthopedic footwear. For this purpose, the hyper-elastic behavior materials, including styrene-butadiene rubber, silicon, Plastazote foam, polyfoam, ethylene-vinyl acetate foam, polyurethane foam, and polyurethane, have been investigated, with different degree of hardness as well as one layer of composite with Kevlar fiber, whose effect is reducing the pressure exerted to the feet. A combination of materials was used to construct an insole sample, and uniaxial pressure tests were performed for testing its mechanical properties. Then, these properties were used in finite element analysis, whereby the best type of insole for the footwear was chosen and fabricated. The results of finite element analysis were validated using Pedar system and after performing the experimental tests both statically and dynamically. Experimental and numerical investigations suggested that the sole material of orthopedic shoe should be selected as styrene-butadiene rubber. The internal layers of styrene-butadiene rubber frame from top to bottom should be comprised of Plastazote-polyurethane with Kevlar fiber-silicon shore A6, which can be a suitable orthopedic boot in terms of proper stress and strain distribution. Generally, it could reduce the pressure exerted to the sole by 79% compared with barefoot.