The Effects of Fabric and Conductive Wire Properties on Electromagnetic Shielding Effectiveness and Surface Resistivity of Interlock Knitted Fabrics

E. Sancak,M. Akalin,İ. Usta,M. Yuksek,M.S. Özen 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

Our aim in this study was to investigate the effects of course density, yarn linear density and thickness and type of conductive wire on electromagnetic shielding effectiveness. Metal/cotton conductive composite yarns were produced by the core-spun technique on the ring spinning machine, involving stainless steel, copper and silver coated copper wires with 40 μm, 50 μm, 60 μm thicknesses and Ne10/1 and Ne20/1 count yarns. The interlock fabrics were knitted on a 7G flat knitting machine with the three different machine settings. The EMSE and the surface resistivity of knitted fabrics were measured by the co-axial transmission line method according to the ASTM-D4935-10 standard in the frequency range from 15 to 3000 MHz and by the ASTM D257-07 standard, respectively. It was observed that all fabrics shielded around 95 % of electromagnetic waves at low frequencies, 80 % at medium frequencies and 70 % at high frequencies. Increasing the course density and thickness of conductive wire in interlock knitted fabrics increased the EMSE correspondingly. The knitted fabrics that had been produced with high yarn count showed greater EMSE because there was less isolation. The effect of the metal wire type was highly significant between 15 and 600 MHz.

Observer-based friction compensation in heavy-duty parallel robot control

Kamil Vedat Sancak,Zeki Yagiz Bayraktaroglu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8

This paper presents an experimental study on friction compensation for the high-precision tracking control of parallel manipulators. A Luenberger-like observer (LLO) and an extended state observer (ESO) are designed and implemented in real-time control of a 6-DoF heavy-duty Stewart-Gough platform (SGP). The dynamic Lu-Gre model is used in the identification of friction. Performances of the proposed observer-based friction compensators are compared to those of a model-based compensator in computed torque control. Experimental results show that the observer-based compensators significantly improve the tracking performances in high speed motions. Among the investigated observers, the ESO results in minimum RMS error in position tracking. Improvement in position tracking at velocity reversals of the individual leg motions is also observed with the contribution of observer-based compensation. The observer error dynamics is exponentially stable, and the convergence rate can be arbitrarily increased by tuning the observer gain.

Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material

Erdemir, Ugur,Sancakli, Hande Sar,Sancakli, Erkan,Eren, Meltem Mert,Ozel, Sevda,Yucel, Taner,Yildiz, Esra The Korean Academy of Prosthodonitics 2014 The Journal of Advanced Prosthodontics Vol.6 No.6

PURPOSE. The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS. A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of $6mm{\times}4mm$ and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with $30{\mu}m$ silica oxide particles ($Cojet^{TM}$ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at ${\alpha}=.05$. RESULTS. Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION. Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

Nonlinear Computed Torque Control of 6-DoF Parallel Manipulators

Kamil Vedat Sancak,Zeki Yagiz Bayraktaroglu 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.7

This paper presents an experimental study on high-precision motion control of heavy-duty parallel manipulators. Conventional independent joint control and computed torque control schemes are modified by the introduction of nonlinear loop gains in order to improve tracking performances. Asymptotic stability of the controllers has been analyzed and proved based on the Lyapunov’s direct method. An extended state observer for feedback compensation against disturbances is designed and implemented in the control loops. The observer error dynamics is shown to be exponentially stable and the error convergence rate can be made arbitrarily high by tuning the gain of the observer. Performances of the proposed nonlinear controllers are experimentally investigated in the control of a 6-DoF Stewart-Gough Platform in roll-pitch motion. Comparisons between the proposed controllers and conventional controllers show that tracking precision of the platform is improved through the nonlinear design of the controller gains in both independent joint control and computed torque control schemes. Although the computed torque control method proves to achieve the best tracking precision in high speed motions of the platform legs, independent joint control with nonlinear gains displays challenging performance as an interesting alternative.

Shear bond strength of a new self-adhering flowable composite resin for lithium disilicate-reinforced CAD/CAM ceramic material

Sevda Ozel,Taner Yucel,Esra Yildiz,Meltem Mert Eren,Erkan Sancakli,Hande Sar Sancakli,Ugur Erdemir 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.6

PURPOSE The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of 6 mm × 4 mm and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with 30 µm silica oxide particles (Cojet™ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at α=.05. RESULTS Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.

Breast Cancer Awareness among Turkish Nursing Students

Celik, Sevim,Tasdemir, Nurten,Sancak, Hulya,Demirel, Merve,Akman, Ozlem,Kara, Merve Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Background: This study conducted to determine breast cancer awareness and influencing factors among nursing students in the West Black Sea Region in Turkey. Materials and Methods: This cross-sectional descriptive study was conducted between April-May, 2014. The sample was 270 female nursing students. Data were collected by Personal Information Form and Champion's Health Belief Model Scale (CHBMS). Results: The students' mean age was $21.6{\pm}2.09$ and 81.1% had knowledge about breast cancer from their academic education. It is found that 63.7% of the students performed Breast Self-Examination (BSE) and 11.1% had a family member diagnosed with breast cancer. The CHBMS mean score of the students was $117.7{\pm}14.5$. Conclusions: Breast cancer awareness of nursing students is on a good level and was affected by family history of breast cancer and health beliefs.

Can Fecal Calprotectin Level Be Used as a Markers of Inflammation in the Diagnosis and Follow-Up of Cow's Milk Protein Allergy?

Ömer Faruk Beşer,,Selim Sancak,Tülay Erkan,Tufan Kutlu,Haluk Çokuğraş,Fügen Ç. Çokuğraş 대한천식알레르기학회 2014 Allergy, Asthma & Immunology Research Vol.6 No.1

Purpose: Calprotectin is a cytosolic protein with immunomodulatory, antimicrobial, and antiproliferative actions. The concentration of calprotectin increases in infection, inflammation, and malignancy. We determined if calprotectin can be used as a marker for the diagnosis and follow-up of bowel inflammation in cow’s milk protein allergy (CMPA). Methods: In total, 32 patients newly diagnosed with CMPA were included (24 IgE-mediated, 8 non-IgE-mediated). In all subjects, a complete blood count, total IgE, cow’s milk-specific IgE, and fecal calprotectin (FC) were assessed before and after a cow’s milk protein (CMP) elimination diet was started. The results were compared with those of 39 healthy children. Results: The mean FC value before the CMP elimination diet was 516±311 μg/g in the 32 patients with CMPA and 296±94 μg/g in the control group (P=0.011). The mean FC value after the diet in these patients was 254±169 μg/g, which was significantly different from the mean value before the CMP elimination diet (P<0.001). When we compared FC levels before the CMP elimination diet in the IgE-mediated group with the control group, we found no significant statistical difference (P=0.142). The mean FC value before the CMP elimination diet was 886±278 μg/g in the non-IgE-mediated group and 296±94 μg/g in the control group; this difference was statistically significant (P<0.001). In the IgE-mediated and non-IgE-mediated groups, FC values after CMP elimination diet were 218±90 μg/g and 359±288 μg/g, respectively, and FC values before CMP elimination diet were 392±209 μg/g and 886±278 μg/g, respectively; these differences were statistically significant (P=0.001 and P=0.025, respectively). Conclusions: FC levels may be a useful marker for follow-up treatment and recurrence determination in CMPA.

Unprecedented Electromagnetic Shielding Effectiveness of Lightweight Nonwoven Ag/PA66 Fabrics

M. S. Ozen,E. Sancak,N. Soin,T. H. Shah,A. Zarei,E. Siores 한국섬유공학회 2018 Fibers and polymers Vol.19 No.2

Novel, high-performance silver coated polyamide, Ag/PA66, nonwoven fabrics with a density of only 0.04 g/cm3 have been developed using staple fibres of 19 (3.3 dtex) and 27 (6.7 dtex) μm diameter. The obtained nonwoven fabrics with an Ag loading of 12-18 wt% exhibited excellent weight-normalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm3) in the 0.015-3 GHz range, which is among the highest reported till date. Moreover, the applied microwave was verified to be absorbed rather than being reflected back making the fabrics highly suitable for shielding applications. It was also observed that nonwoven fabrics made from finer 3.3 dtex Ag/PA66 fibres have higher reflection and lower absorption values than their thicker (6.7 dtex) counterparts. Additionally, we have also explored the use of these nonwoven Ag/PA66 fabrics for personal thermal management via Joule heating with samples showing rapid heating response (up to 0.2 oC/sec) and long-term stability measured over 10,000 seconds. The needle-punched Ag/PA66 nonwoven fabrics, in spite of their low density of the order of 0.04 g/cm2, exhibited high EMSE values of nearly 69-80 dB, leading to excellent weightnormalised specific electromagnetic shielding effectiveness of over 1200 dB/(g/cm3) in the 0.015-3 GHz range. The production of Ag/PA66 needle punched nonwoven fabrics thus offers a facile route to develop multifunctional fabrics for EMI shielding as well as personal thermal management applications.

Prevalence of Daytime Urinary Incontinence and Related Risk Factors in Primary School Children in Turkey

Deniz Bolat,Ismail Cenk Acar,Ali Ersin Zumrutbas,Saadettin Eskicorapci,Eyup Burak Sancak,Mehmet Zencir,Tahir Turan,Zafer Sinik 대한비뇨의학회 2014 Investigative and Clinical Urology Vol.55 No.3

Purpose: Urinary incontinence is one of the major urinary symptoms in children andadolescents and can lead to major distress for the affected children and their parents. In accordance with the definitions of the Standardization Committee of theInternational Children’s Continence Society, daytime urinary incontinence (DUI) isuncontrollable leakage of urine during the day. The aim of this cross-sectional studywas to investigate the prevalence and associated risk factors of DUI in Turkish primaryschool children. Materials and Methods: The questionnaire, which covered sociodemographic variablesand the voiding habits of the children, was completed by the parents of 2,353 childrenwho were attending primary school in Denizli, a developing city of Turkey. The children’svoiding habits were evaluated by use of the Dysfunctional Voiding andIncontinence Symptoms Score, which is a validated questionnaire. Children with a historyof neurological or urological diseases were excluded. Results: The participation rate was 91.9% (2,164 people). The overall prevalence of DUIwas 8.0%. The incidence of DUI tended to decrease with increasing age and was notsignificantly different between genders (boys, 8.8%; girls, 7.3%; p=0.062). Age, maternaleducation level, family history of daytime wetting, settlement (urban/rural), historyof constipation, urinary tract infection, and urgency were independent risk factors ofDUI. Conclusions: Our findings showed that DUI is a common health problem in primaryschool children. In an effort to increase awareness of children’s voiding problems andthe risk factors for urinary dysfunction in the population, educational programs andlarger school-based screening should be carried out, especially in regions with low socioeconomic status.

터키산 통거미 신종의 형태학적 연구: Paranemastoma karolianus sp.

일카이 코락 외칼,압둘라 바이람,나지페 이지트,자페르 산칵,Ocal, Ilkay Corak,Bayram, Abdullah,Yigit, Nazife,Sancak, Zafer Korean Society of Applied Entomology 2017 한국응용곤충학회지 Vol.56 No.3

본 연구에서는 북부 터키에서 Paranemastoma속의 통거미 1신종을 기재하였다. 본 종Paranemastoma karolianus의 다리, 등면 표피 및 생식기의 미세구조를 제시하였다. 본 신종과 유사종과의 구별점에 대하여 고찰하였다. In this study, a new opilionid species of Paranemastoma Redikorzevi, 1936 is described from northern Turkey. Fine structures of extremities, dorsal integument and genitalia of Paranemastoma karolianus sp. n. are presented. Differences between the new species and related species are discussed.