Analytical and experimental investigation of rake contact and friction behavior in metal cutting

In this study, the friction behavior in metal cutting operations is analyzed using a thermomechanical cutting process model that represents the contact on the rake face by sticking and sliding regions. The relationship between the sliding and the overall, i.e. apparent, friction coefficients are analyzed quantitatively, and verified experimentally. The sliding friction coefficient is identified for different workpiece-tool couples using cutting and non-cutting tests. In addition, the effect of the total, sticking and sliding contact lengths on the cutting mechanics is investigated. The effects of cutting conditions on the friction coefficients and contact lengths are analyzed. It is shown that the total contact length on the rake face is 3-5 times the feed rate. It is observed that the length of the sliding contact strongly depends on the cutting speed. For high cutting speeds the contact is mainly sliding whereas the sticking zone can be up to 30% of the total contact at low speeds. From the model predictions and measurements it can be concluded that the sticking contact length is less than 15% for most practical operations. Furthermore, it is also demonstrated that the true representation of the friction behavior in metal cutting operations should involve both sticking and sliding regions on the rake face for accurate predictions. Although the main findings of this study have been observed before, the main contribution of the current work is the quantitative analysis using an analytical model. Therefore, the results presented in this study can help to understand and model the friction in metal cutting

An alternative anterior tension free preperitoneal patch technique by help of the endoscope for femoral hernia repair

AbstractBackgroundFemoral hernias are relatively uncommon and have a higher risk for strangulation and incarceration. We introduce an alternative anterior tension free inlay patch technique by help of the endoscope for femoral hernia repair.MethodCharacteristics of patients undergoing femoral hernia repair between March 2006–April 2011 and description of the surgical technique is presented.ResultsWe analyzed our experience with this technique in 26 consecutive patients with femoral hernias (1 bilateral, 15 right, 10 left femoral hernia) in 5 year period. Seven of these 26 femoral hernias were recurrent and 2 of them were concomitant with inguinal hernia. Mean operation time was 30.0 ± 12.1 min. Seroma was seen in 2 patients at postoperative 1st week. There were no; hematoma, wound infection and separation of wound edges and early recurrence at postoperative 1st week and 1st month. The mean follow up period was 41.8 ± 18.2 months. All of 22 patients who were contacted were satisfied with the operation. There was no recurrence, chronic pain and foreign body feeling in any patient at the end of the follow-up period.ConclusionThis feasible and safe alternative anterior inlay patch repair might be used in all femoral hernias with the exception of the ones requiring intestinal resection

Evaluation of problems of late premature infants during the first 15 days of their lives [Geç prematüre dogan bebeklerin postnatal ilk 15 günde karşilaştiklari sorunlarin degerlendirilmesi]

Because of the increase in ceserean section, assited fertilization and multiple births, late preterem births was suspected to be increased. We aimed to investigate the incidence of late preterm births in our hospital and evaluate their postnatal medical problems in this study. Late premature infants born alive between 340/7- 366/7 pregnancy weeks between January 1, 2013 and December 31, 2014 in Çukurova University Faculty of Medicine Hospital Gynecology and Obstetrics Clinic were included in this study. Problems faced by these infants in the first 15 days were evaluated retrospectively. A total of 3716 infants (97 twins and 22 triplets) were induced in the study. Late premature 641 infants (30 twins and 7 triplet births) constituted 17.2% of all infants born. Jaundice in 208 late premature infants (44.6%), feeding intolerance in 124 infants (26.6%), transient tachypnea of newborn in 60 infants (12.9%), hypoglycemia in 48 infants (10.3%), respiratory distress syndrome in 41 infants (8.8%), pneumonia in 36 infants (7.7%), early neonatal sepsis in 18 infants (3.9%), nosocomial sepsis in 6 infants (1.3%) and necrotizing enterocolitis in one baby (0.2%) were detected. 59 infants (12.7%) were hospitalized longer than postnatal 15 days. 44 (10.8%) of the infants who reapplied to the hospital again were rehospitalized. As a result, it is significantly important to evaluate late preterm infants in newborn period for diseases which may develop such as feeding intolerance, hypoglycemia, respiratory problem and infection risk

The comparison of local warming and lidocaine injection techniques for the prevention of rocuronium injection pain

Objective: Rocuronium-linked injection pain often occurs. In this study, we aimed to compare the local heating of the injection site and the iv lidocaine administration in the prevention of injection pain with rocuronium. Method: In the ASA I-II risk group, scheduled for operation in the context of general anesthesia with ethics committee approval and written approval, 60 patients aged 18-65 years were included in the study in 3 randomly assigned groups. Tourniquets were applied to the front arm in all three groups. In group 1 (n = 20) 2 ml of saline was administered iv; thirty seconds later the turnstile opened; 1 ml (10 mg) of rocuronium was applied for 2 seconds. In group 2 (n = 20) the patient's arm was warmed externally with the patient's heating blanket adjusted to 43 °C; turnstile opened at 30th; external heating was applied for a total of 1 minute; followed by 1 ml (10 mg) of rocuronium for 2 seconds. In Group 3 (n = 20), 1ml (10 mg) rocuronium was administered for 2 seconds following 2 ml of 2% lidocaine iv. Following rocuronium injection in the intubation dose, the pain was assessed by a 4-point traction response score. Results: The groups were similar in terms of demographics. The 4 point verbal rating scales were significantly different in Group 1, compared to Group 2 and Group 3 (2,0+0,8 and 0,5+0,5 and 0,3+0,4, mean+SD). There was no statistically significant difference between Groups 2 and 3. The 4 point withdrawal response scores and the number of patients who had withdrawal response were found to be significantly higher in Group 2, and no statistical difference between Groups 1 and 3. Conclusion: Local heating or lidocaine applications may be used to prevent injection pain during priming of rocuronium. We believe that both administration of lidocaine can be preferred to local heating in the prevention of rocuronium-induced mild withdrawal response at the intubation dose, and that both treatments prevent severe response

The efficacy of Botulinum Toxin A in poststroke spasticity

To assess the efficacy of the Botulinum Toxin A (BTX-A) on spasticity, motor evaluation, function and quality of life in patients with spasticity of upper and lower extremity following hemiplegia. Spasticity was assessed with Modified Ashworth Scale (MAS), motor function of upper and lower extremities and hand of hemiplegic side were evaluated with Brunnstrom neurophysiologic evaluation, mobilization was assessed with Rivermead Motor Assessment (RMA), upper extremity function was evaluated with Fugl Meyer (FM), functional assesment was evaluated with Functional Independence Measure (FIM), quality of life was assessed with Short Form 36 (SF-36) at baseline and at week 6. Sixteen patients (4 right hemiplegia, 12 left hemiplegia) with mean age of 47.56±17.2 years were included. BTX-A was injected into the forearm flexors in 7 cases, pronators in 6 cases, wrist flexors in 6 cases, finger flexors in 10 cases, and ankle flexors in 8 cases with a total dose of 300 U for each case. Significant improvements were detected for MAS of all muscles which were BTX-A injected compared to pretreatment. Significant improvements were detected for Brunnstrom evaluation of hand, RMA, FM and FIM compared to pretreatment. While significant improvement was found for only role limitations due to physical problems subgroup of SF-36, there was no statistical difference for other subgroups. Botulinum toxin A is safe regarding side effects, and improves the functional capacity of patient in the treatment of spasticity

Interstitial mycosis fungoides: a rare variant

WOS: 000443414101353