Prediction of the turning and zig-zag maneuvering performance of a surface combatant with URANS

Duman, Suleyman,Bal, Sakir Techno-Press 2017 Ocean systems engineering Vol.7 No.4

The main objective of this study is to investigate the turning and zig-zag maneuvering performance of the well-known naval surface combatant DTMB (David Taylor Model Basin) 5415 hull with URANS (Unsteady Reynolds-averaged Navier-Stokes) method. Numerical simulations of static drift tests have been performed by a commercial RANS solver based on a finite volume method (FVM) in an unsteady manner. The fluid flow is considered as 3-D, incompressible and fully turbulent. Hydrodynamic analyses have been carried out for a fixed Froude number 0.28. During the analyses, the free surface effects have been taken into account using VOF (Volume of Fluid) method and the hull is considered as fixed. First, the code has been validated with the available experimental data in literature. After validation, static drift, static rudder and drift and rudder tests have been simulated. The forces and moments acting on the hull have been computed with URANS approach. Numerical results have been applied to determine the hydrodynamic maneuvering coefficients, such as, velocity terms and rudder terms. The acceleration, angular velocity and cross-coupled terms have been taken from the available experimental data. A computer program has been developed to apply a fast maneuvering simulation technique. Abkowitz's non-linear mathematical model has been used to calculate the forces and moment acting on the hull during the maneuvering motion. Euler method on the other hand has been applied to solve the simultaneous differential equations. Turning and zig-zag maneuvering simulations have been carried out and the maneuvering characteristics have been determined and the numerical simulation results have been compared with the available data in literature. In addition, viscous effects have been investigated using Eulerian approach for several static drift cases.

Retrospective Analysis of Neoadjuvant Chemotherapy for Breast Cancer in Turkish Patients

Duman, Berna Bozkurt,Afsar, Cigdem Usul,Gunaldi, Meral,Sahin, Berksoy,Kara, I. Oguz,Erkisi, Melek,Ercolak, Vehbi Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Background: Neoadjuvant systemic chemotherapy is the accepted approach for women with locally advanced breast cancer. Anthracycline- and taxane-based regimens have been extensively studied in clinical trials and consequently are widely used. In this study aimed to research the complete response (pCR) rates in different regimens for neoadjuvant setting and determine associated clinical and biological factors. Methods: This study included 63 patients diagnosed with breast carcinoma among 95 patients that had been treated with neoadjuvant chemotherapy between 2007 and 2010. TNM staging system was used for staging. The histologic response to neoadjuvant chemotherapy was characterized as a pCR when there was no evidence of residual invasive tumor in the breast or axillary lymph nodes. Biologic subclassification using estrogen receptor (ER), progesterone receptor (PR), HER2 were performed. Luminal A was defined as ER+, PR+, HER2-; Luminal B tumor was defined as ER+, PR-, HER2-; ER+, PR-, HER2+; ER-, PR+, HER2-; ER+, PR+, HER2+; HER2 like tumor ER-, PR+, HER2+; and triple negative tumor ER, PR, HER2 negative. Results: Patients median age was 54.14 (min-max: 30-75). Thirty-two patients (50.8%) were premenapousal and 31 (49.2%) were postmenapousal. Staging was performed postoperatively based on the pathology report and appropriated imaging modalities The TNM (tumor, lymph node, metastasis) system was used for clinical and pathological staging. Fifty-seven (90.5%) were invasive ductal carcinomas, 6 (9.5%) were other subtypes. Thirty nine (61.9%) were grade II and 24 (38.1%) were grade III. Seven (11.1%) patients were stage II and 56 (88.9) patients were stage III. The patients were classified for ER, PR receptor and HER2 positivity. Seventeen patients had complete response to chemotherapy. Forty patients (63.5%) were treated with dose dense regimen (cyclophosphamide 600 mg/m2 and doxorubicine 60 mg/m every two weeks than paclitaxel 175 mg/m2 every two weeks with filgrastim support) 40 patients (48%) were treated anthracycline and taxane containing regimens. Thirteen patients (76%) from 17 patients with pCR were treated with the dose dense regimen but without statistical significance (p=0.06). pCR was higher in HER2(-), ER(-), grade III, premenopausal patients. Conclusion: pCR rate was higher in the group that treated with dose dense regimen, which should thus be the selected regimen in neoadjuvant setting. Some other factors can predict pCR in Turkish patients, like grade, menopausal status, triple negativity, percentage of ER positivity, and HER2 expression.

Biological responses of a non-target aquatic plant (Nasturtium officinale) to the herbicide, tribenuron-methyl

Duman, Fatih,Urey, Erkan,Temizgul, Ridvan,Bozok, Fuat The Korean Society of Weed Science and The Turfgra 2010 Weed Biology and Management Vol.10 No.2

To assess its response to the herbicide, tribenuron-methyl, samples of Nasturtium officinale were exposed to 0, 0.01, 0.05, 0.1, and 0.5 $mg\;L^{-1}$ of tribenuron-methyl for 1, 2, 4 and 7 days. The influence of this herbicide on the relative growth rate, electrolyte leakage, lipid peroxidation, photosynthetic pigmentation, protein content, and performance of anti-oxidant enzymes, such as superoxide dismutase (SOD), catalase, and ascorbate peroxidase (APX), was examined. The results indicated that tribenuron-methyl, applied at 0.5 $mg\;L^{-1}$, affected plant growth negatively. It also was determined that chlorophyll a is the most responsive photosynthetic pigment to tribenuron-methyl exposure. Under stress conditions, the anti-oxidant enzymes were up-regulated compared to the control. The SOD activity was significantly stimulated, while the activity of APX was inhibited. A significant correlation was found between lipid peroxidation and SOD activity. The exposure period and herbicide concentration had significant effects on the biological responses against tribenuron-methyl stress. These results may be useful for clarifying the effect of herbicides on non-target aquatic plants.

Retrospective Analysis of 498 Primary Soft Tissue Sarcomas in a Single Turkish Centre

Duman, Berna Bozkurt,Gunaldi, Meral,Ercolak, Vehbi,Afsar, Cigdem Usul,Sahin, Berksoy,Erkisi, I. Melek Koksal,Kara, Oguz,Paydas, Semra,Gonlusen, Gulfiliz,Sertdemir, Yasar Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Background: Soft tissue sarcomas (STS) must be managed with a team involving pathologists, radiologists, surgeons, radiation therapists and medical oncologists. Treatment modalities and demographic charasteristics of Turkish STS were analysed in the current study. Material-Methods: Primary adult STS followed between 1999-2010 in Cukurova University Medical Faculty Department of Medical Oncology were analzied retrospectively Results: Of the total of 498 patients, 238 were male and 260 female. The most seen adult sarcomas were leomyosarcoma (23%). Localization of disease was upper extremity (8.8%), lower extremity (24.7%), head-neck 8.2%, thoracic 8%, retroperitoneal 5.6%, uterine 12.4%, abdominal 10%, pelvic region 3.6 and other regions 10%. Some 13.1% were early stage, 10.2% locally advanced, 8.2% metastatic and 12.2% recurrent disease. Patients were treated with neoadjuvant/adjuvant (12%) or palliative chemotherapy (7.2%) and 11.4% patients did not receive chemotherapy. Surgery was performed as radical or conservative. The most preferred regimen was MAID combination chemotherapy in the rate of 17.6%. The most common metastatic site was lung (18.1%). The overall survival was 45 months (95%CI 30-59), 36 months in men and 55 months in women, with no statistically significant difference (p=0.5). The survival rates were not different between the group of adjuvant and palliative chemotherapy (respectively 28 versus 18 months) (p=0.06), but radical surgery at 37 months was better than 22 months for conservative surgery (p=0.0001). No differences were evident for localization (p=0.152). Locally advanced group had higher overall survival rates (72 months) than other stages (p=0.0001). Conclusion: STS can be treated successfully with surgery, chemotherapy and radiotherapy. The survival rates of Turkish people were higher in locally advanced group; these results show the importance of multimodality treatment approach and radical surgery.

Effects of Definitive Chemoradiotherapy on Respiratory Function Tests and Quality of Life Scores During Treatment of Lung Cancer

Duman, Evrim,Yildirim, Mustafa,Kaya, Vildan,Ozturk, Duriye,Inal, Aysun,Akarsu, Zeynep,Gunduz, Seyda,Yildiz, Mustafa Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: Chemoradiotherapy is an important treatment modality for lung cancers. The aim of this study was to investigate alterations in, as well as the interrelationship between, lung function and quality of life of patients receiving chemoradiotherapy due to locally advanced non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) limited to the thorax. Materials and Methods: The study included patients receiving definitive chemoradiotherapy for lung carcinoma. The respiratory function of the patients was assessed by measuring forced expiratory volume in 1 s per unit (FEV1) and forced expiratory volume in 1s per unit of vital capacity (FEV1/VC) before, in the middle of and after treatment. During the study, EORTC QLQ C30 and LC13 questionnaires developed by the Committee of the European Organization for Research and Treatment of Cancer (EORTC) were employed to evaluate the quality of life on the same day as respiratory function tests (RFT). Findings: The study included 23 patients in total: 19 (82.6%) diagnosed with NSCLC and 4 (17.4%) with SCLC. The average percentage FEV1 was $55.6{\pm}21.8%$ in the pre-treatment period, $56.2{\pm}19.2%$ in the middle of treatment and $60.4{\pm}22%$ at the end of treatment. The improvement in functional scores, symptom scores and general health scores during treatment was not statistically significant (P= 0.568, P= 0.734, P= 0.680, P=0.757 respectively). Conclusions: Although this study showed an improvement in respiratory function and quality of life of patients during treatment with thoracic chemoradiotherapy, no statistically significant results were obtained. While evaluating the effectiveness of treatments for lung carcinoma, the effects of treatment on respiratory function and quality of life should be considered.

Assessment of liquefaction potential of the Erzincan, Eastern Turkey

Duman, Esra Subasi,Ikizler, Sabriye Banu,Angin, Zekai,Demir, Gokhan Techno-Press 2014 Geomechanics & engineering Vol.7 No.6

This study includes determination of liquefaction potential in Erzincan city center. Erzincan Province is situated within first-degree earthquake zone on earthquake map of Turkey. In this context, the earthquake scenarios were produced using the empirical expressions. Liquefaction potential for different earthquake magnitudes (6.0, 6.5, 7.0) were determined. Liquefaction potential was investigated using Standard Penetration Test (SPT). Liquefaction potential analyses are determined in two steps: geotechnical investigations and calculations. In the first steps, boreholes were drilled to obtain disturbed and undisturbed soil samples and SPT values were obtained. Laboratory tests were made to identify geotechnical properties of soil samples. In the second step, liquefaction potential analyses were examined using two methods, namely Seed and Idriss (1971), Iwasaki et al. (1981). The liquefaction potential broadly classified into three categories, namely non-liquefiable, marginally liquefiable and liquefiable regions. Additionally, the liquefaction potential index classified into four categories, namely non-liquefiable, low, high and very high liquefiable regions. In order to liquefaction analysis complete within a short time, MATLAB program were prepared. Following the analyses, liquefaction potential index is investigated by Iwasaki et al. (1982) methods. At the final stage of this study, liquefaction potential maps and liquefaction potential index maps of the all study area by using IDW (inverse distance weighted) interpolation method in Geostatistical Analyst Module of ArcGIS 10.0 Software were prepared for different earthquake magnitudes and different depths. The results of soil liquefaction potential were evaluated in ArcGIS to map the distributions of drillings with liquefaction potential. The maps showed that there is a spatial variability in the results obtained which made it difficult to clearly separate between regional areas of high or low potential to liquefy. However, this study indicates that the presence of ground water and sandy-silty soils increases the liquefaction potential with the seismic features of the region.

Intelligent Association in Agent-based Ubiquitous Computing Environments

H. Duman,H. Hagras,V. Callaghan,G. Clarke,M. Colley 제어로봇시스템학회 2002 제어로봇시스템학회 국제학술대회 논문집 Vol.2002 No.10

Temperature dependent capacitance and DLTS studies of Ni/n-type 6H-SiC Schottky diode

Songül Duman,Emre Gür,Seydi Dogan,Sebahattin Tüzemen 한국물리학회 2009 Current Applied Physics Vol.9 No.6

Ni/n-type 6H-SiC Schottky barrier diode (SBD) has been characterized by the capacitance–voltage (C–V) technique as a function of temperature (120–500 K). The barrier height (BH) was determined as 1.36 eV at the temperature of 300 K and frequency of 50 kHz from C–V measurements, respectively. The BH for the Ni/n-type 6H-SiC does not exhibit temperature dependence between 260 and 500 K, while it changes slightly with decreasing temperature between 120 and 240 K. Deep level transient spectroscopy (DLTS) has been used to investigate deep levels in Ni/n-type 6H-SiC SBD. The four electron trap centers to be present at temperatures 120, 200, 350 and 415 K have been realized. The origin of these defects has been decided to be intrinsic nature and it has been found the correlation between C–V and DLTS measurements quite interesting. Ni/n-type 6H-SiC Schottky barrier diode (SBD) has been characterized by the capacitance–voltage (C–V) technique as a function of temperature (120–500 K). The barrier height (BH) was determined as 1.36 eV at the temperature of 300 K and frequency of 50 kHz from C–V measurements, respectively. The BH for the Ni/n-type 6H-SiC does not exhibit temperature dependence between 260 and 500 K, while it changes slightly with decreasing temperature between 120 and 240 K. Deep level transient spectroscopy (DLTS) has been used to investigate deep levels in Ni/n-type 6H-SiC SBD. The four electron trap centers to be present at temperatures 120, 200, 350 and 415 K have been realized. The origin of these defects has been decided to be intrinsic nature and it has been found the correlation between C–V and DLTS measurements quite interesting.

Pell and Pell-Lucas numbers which are concatenations of two repdigits

Merve Güney Duman,Fatih Erduvan 호남수학회 2023 호남수학학술지 Vol.45 No.4

In this study, we search for Pell and Pell-Lucas numbers, which are concatenations of two repdigits and find these numbers to be only 12, 29, 70 and 14, 34, 82, respectively. We use Baker’s Theory and Baker-Davenport basis reduction method while finding the solutions.

Biometrical Variation of Posidonia oceanica with Different Bottom Types Along the Entire Turkish Mediterranean Coast

Mutlu Erhan,Duman Güler Sıla,Karaca Doğukan,Özvarol Yaşar,Şahin Ahmet 한국해양과학기술원 2023 Ocean science journal Vol.58 No.1

The biometrical dynamics of Posidonia oceanica were studied with regard to variation and its depthwise extension with four major bottom types along the entire Turkish Mediterranean coasts in winter and summer during 2019. The bottom type which mainly consisted of rock, matte (hard bottom), sand, and mud (soft bottom) was a key determinant for biometrical (density and morphometric) changes which were more prominent in summer. The upper and lower limits of vertical depthwise extension of the meadows were restricted by the zonal distribution of the hard bottom. The limits were not restricted on the soft bottom. However, some large areas of the soft bottoms were devoid of the meadows depending on the existence of mobile substrate affected by the high dynamic of water movement. The density variables were higher on hard bottoms than on the soft bottoms; the inter-nodal distance was longer on matte than on rock, sand, and mud, in contrast to leaf biomass. Mud had the lowest number of leaves per shoot and shoot density, whereas rock had the highest number. The shortest rhizome was measured on the rock, while the longest rhizome was measured on matte, which also had the longest leaves. The soft bottoms had wider leaves than the hard bottoms had. Besides the seasonal and depthwise differences in the biometrics, the biometrics were separately assembled between rock and mud. Contrary to the morphometric variables, the density biometrics decreased linearly from the hard bottom to the soft bottom.