External Control Interface, Dynamic Modeling and Parameter Estimation of a Research Treadmill

Treadmills providing linear continuous movement are used for robotic testing of prostheses in order to study their operating characteristics. However, traditional exercise treadmills are not able to simulate various conditions such as avoiding an obstacle, climbing, descending, reversing direction, or stopping instantly. The focus of this thesis is to examine control algorithms (position, speed and force) for the drive mechanism of a research treadmill to fulll the gap in the situations described above. The system consists of a power supply, a computer with Matlab, and the treadmill that includes a DC motor, a pulley and belt. Also, an external encoder is installed on the motor to measure the position of the belt. The bond graph method is used to model the system to nd the symbolic transfer function. Simultaneously, system identication techniques are used to estimate a numeric transfer function. Some parameters of the model are experimentally measured, and the rest are extracted by matching two transfer functions. Control algorithms such as proportional-integralderivative and sliding mode are implemented in the system for simulation and realtime operation. The results demonstrate that this system is suitable for producing motion paths that traditional treadmills cannot, and it can handle dicult-to-model situations such as the synchronized movement of the treadmill with a prosthesistesting robo

External Control Interface, Dynamic Modeling and Parameter Estimation of a Research Treadmill

Treadmills providing linear continuous movement are used for robotic testing of prostheses in order to study their operating characteristics. However, traditional exercise treadmills are not able to simulate various conditions such as avoiding an obstacle, climbing, descending, reversing direction, or stopping instantly. The focus of this thesis is to examine control algorithms (position, speed and force) for the drive mechanism of a research treadmill to fulll the gap in the situations described above. The system consists of a power supply, a computer with Matlab, and the treadmill that includes a DC motor, a pulley and belt. Also, an external encoder is installed on the motor to measure the position of the belt. The bond graph method is used to model the system to nd the symbolic transfer function. Simultaneously, system identication techniques are used to estimate a numeric transfer function. Some parameters of the model are experimentally measured, and the rest are extracted by matching two transfer functions. Control algorithms such as proportional-integralderivative and sliding mode are implemented in the system for simulation and realtime operation. The results demonstrate that this system is suitable for producing motion paths that traditional treadmills cannot, and it can handle dicult-to-model situations such as the synchronized movement of the treadmill with a prosthesistesting robo

Linear accelerator-based stereotactic radiosurgery in recurrent glioblastoma: A single center experience

Background/Aim. Management of patients with recurrent glioblastoma (GB) comprises a therapeutic challenge in neurooncology owing to the aggressive nature of the disease with poor local control despite a combined modality treatment. The majority of cases recur within the highdose radiotherapy field limiting the use of conventional techniques for re-irradiation due to potential toxicity. Stereotactic radiosurgery (SRS) offers a viable noninvasive therapeutic option in palliative treatment of recurrent GB as a sophisticated modality with improved setup accuracy allowing the administration of high-dose, precise radiotherapy. The aim of the study was to, we report our experience with single-dose linear accelerator (LINAC) based SRS in the management of patients with recurrent GB. Methods. Between 1998 and 2010 a total of 19 patients with recurrent GB were treated using single-dose LINAC-based SRS. The median age was 47 (23-65) years at primary diagnosis. Karnofsky Performance Score was ≥ 70 for all the patients. The median planning target volume (PTV) was 13 (7-19) cc. The median marginal dose was 16 (10-19) Gy prescribed to the 80%-95% isodose line encompassing the planning target volume. The median follow-up time was 13 (2-59) months. Results. The median survival was 21 months and 9.3 months from the initial GB diagnosis and from SRS, respectively. The median progression-free survival from SRS was 5.7 months. All the patients tolerated radiosurgical treatment well without any Common Toxicity Criteria (CTC) grade > 2 acute side effects. Conclusion. Single-dose LINAC-based SRS is a safe and well- tolerated palliative therapeutic option in the management of patients with recurrent GB

Thermal and mechanical properties of LDPE by the effects of organic peroxides

WOS: 000403007800012In this study, the effect of different organic peroxides on different types of low-density polyethylene (LDPE) was investigated. LDPE products like F2-21T, F5-21T, and I22-19T were mixed in different proportions with dialkyl peroxide, dibenzoyl peroxide, and dilauroyl peroxide. Melt flow rates, mechanical properties (tensile strength at yield, tensile strength at break, elongation at break, and stress-strain effect), thermal analysis (differential scanning calorimetric and thermogravimetric analysis), and scanning electron microscopy images of the prepared mixtures were examined. Cross-linking occurred in the structure of LDPE types having different molecular weight distribution by the addition of even small amounts of peroxide (e.g. 0-0.12wt%). Copyright (c) 2017 John Wiley & Sons, Ltd

Clinical and Surgical Evaluation of Perineal Hernia in Dogs: 41 Cases

Besalti, Omer/0000-0002-7819-9094;WOS: 000278958100007The purpose of the study was to report the clinical and surgical records of perineal hernia and associated rectal pathology with epidural morphine analgesia in 41 dogs. Fourty one dogs suffered from perineal hernia were included into the study with the age varied from 4.5 to 16 years. Eleven dogs had bilateral while the other 30 had unilateral (17 right, 13 left) perineal hernia. The clinical signs were perianal swelling (n=41), severe tenesmus (n=19), dyschesia (n=9), proctitis (n=7), fecal incontinence (n=4), stranguria (n=2) and hematuria (n=1). Associated rectal pathologies were diverticulation (n=15), dilatation (n=4), deviation (n=3) and sacculation (n=1). The rectal diverticulum was corrected by extraluminal plication (n=12) or rectal resection (n=3). Internal obturator muscle flap transposition was used to repair the hernia in all cases. Postoperative pain was subjectively evaluated and scores were "no pain" in 10 cases, mild in 28 cases, moderate in 3 cases. Mean follow-up time was 27.3 months (range 4 months to 5 years) and the recurrence was observed only in three cases postoperatively. In conclusion, combined perineal herniorraphy with internal obturator muscle transposition and rectal wall repairment can be carried out at the same time and epidural morphine administration provide adequate analgesia for these operations

Electroadhesion with application to touchscreens

There is growing interest in touchscreens displaying tactile feedback due to their tremendous potential in consumer electronics. In these systems, the friction between the user's fingerpad and the surface of the touchscreen is modulated to display tactile effects. One of the promising techniques used in this regard is electrostatic actuation. If, for example, an alternating voltage is applied to the conductive layer of a surface capacitive touchscreen, an attractive electrostatic force is generated between the finger and the surface, which results in an increase in frictional forces acting on the finger moving on the surface. By altering the amplitude, frequency, and waveform of this signal, a rich set of tactile effects can be generated on the touchscreen. Despite the ease of implementation and its powerful effect on our tactile sensation, the contact mechanics leading to an increase in friction due to electroadhesion has not been fully understood yet. In this paper, we present experimental results for how the friction between a finger and a touchscreen depends on the electrostatic attraction and the applied normal pressure. The dependency of the finger–touchscreen interaction on the applied voltage and on several other parameters is also investigated using a mean field theory based on multiscale contact mechanics. We present detailed theoretical analysis of how the area of real contact and the friction force depend on contact parameters, and show that it is possible to further augment the friction force, and hence the tactile feedback displayed to the user by carefully choosing those parameters

Contact mechanics between the human finger and a touchscreen under electroadhesion

The understanding and control of human skin contact against technological substrates is the key aspect behind the design of several electromechanical devices. Among these, surface haptic displays that modulate the friction between the human finger and touch surface are emerging as user interfaces. One such modulation can be achieved by applying an alternating voltage to the conducting layer of a capacitive touchscreen to control electroadhesion between its surface and the finger pad. However, the nature of the contact interactions between the fingertip and the touchscreen under electroadhesion and the effects of confined material properties, such as layering and inelastic deformation of the stratum corneum, on the friction force are not completely understood yet. Here, we use a mean field theory based on multiscale contact mechanics to investigate the effect of electroadhesion on sliding friction and the dependency of the finger–touchscreen interaction on the applied voltage and other physical parameters. We present experimental results on how the friction between a finger and a touchscreen depends on the electrostatic attraction between them. The proposed model is successfully validated against full-scale (but computationally demanding) contact mechanics simulations and the experimental data. Our study shows that electroadhesion causes an increase in the real contact area at the microscopic level, leading to an increase in the electrovibrating tangential frictional force. We find that it should be possible to further augment the friction force, and thus the human tactile sensing, by using a thinner insulating film on the touchscreen than used in current devices

Fingerpad contact evolution under electrovibration.

Displaying tactile feedback through a touchscreen via electrovibration has many potential applications in mobile devices, consumer electronics, home appliances and automotive industry though our knowledge and understanding of the underlying contact mechanics are very limited. An experimental study was conducted to investigate the contact evolution between the human finger and a touch screen under electrovibration using a robotic set-up and an imaging system. The results show that the effect of electrovibration is only present during full slip but not before slip. Hence, the coefficient of friction increases under electrovibration as expected during full slip, but the apparent contact area is significantly smaller during full slip when compared to that of no electrovibration condition. It is suggested that the main cause of the increase in friction during full slip is due to an increase in the real contact area and the reduction in apparent area is due to stiffening of the finger skin in the tangential direction

Testis Involvement in Neuroblastoma: Report of 3 Cases in the Turkish Pediatric Oncology Group-Neuroblastoma Study and Review of the Literature

Background: Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. Primary and secondary testicular involvement is extremely uncommon in neuroblastoma. Procedure: All children with neuroblastoma treated with the Turkish Pediatric Oncology Group (TPOG)-Neuroblastoma (NB) Study and who had testis involvement either at diagnosis or at relapse were retrospectively evaluated. A review of all cases with neuroblastoma and testis involvement in the literature was done. Results: There were 3 children with NB documented to have involvement of the testis, 2 at diagnosis, 1 at recurrence, within the 559 cases (0.5%) treated with the Turkish Pediatric Oncology Group (TPOG)-Neuroblastoma Protocol. All had advanced stage. Two were infants. A total of 57 cases of testicular or paratesticular neuroblastoma have been reported in children, and most cases represent metastases as in the 3 cases in our series. Conclusions: Neuroblastoma should be considered in the differential diagnosis of testicular mass and work-up for neuroblastoma should be done before orchiectomy. Scrotal ultrasonography should be used as the first diagnostic tool and abdominal ultrasonography shall be done additionally. Testis examination should be performed at diagnosis and regularly during follow-up for boys diagnosed with neuroblastoma. Testes may be sanctuary sites when neuroblastoma is metastatic, as is the case in leukemia