Efect of Irradiance Measurement Sensors on the Performance Ratio of Photovoltaic Power Plant Under Real Operating Conditions: An Experimental Assessment in Turkey

Kivanc Basaran 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.6

The performance analysis of photovoltaic (PV) plants plays an important role in making investment decisions, creating more efcient designs, and in the operation and maintenance decisions in new plants. In addition, performance analysis provides a way to identify real-time operational problems and allows comparisons among diferent PV plants. Performance of PV plants can be indexed with many parameters, but service providers are giving energy guarantees according to their performance ratio (PR). There are many factors that afect PR, such as irradiation, temperature, wind speed, humidity and soiling. But, the most important factors afecting PR are irradiation and temperature. Hence, both the irradiation and the temperature must be measured correctly. Solar irradiation is usually measured with a pyranometer or reference cell. However, there are diferences between the obtained data from these two sensors, which afects the PR signifcantly. In this study, the PR of an MW PV plant installed in Turkey was investigated. Two types of irradiation sensors (pyranometer and reference cells) and PVGIS program were used. The data were collected every 5 min during 1 year. The data passed through quality control and fltered process and some improper values were removed from the row data set. In addition, new data were written instead of the missing data. PR was calculated by using conventional and corrected method. As a result, the average annual PR is determined to be 81.05%, 79.04% and 78.96% and the corrected PR is determined to be 83.69%, 82.48% and 80.87% using the reference cell, pyranometer and PVGIS program, respectively

The effect of different adhesive system applications on push-out bond strengths of glass fiber posts

Kivanc, Bagdagul Helvacioglu,Arisu, Hacer Deniz,Uctasli, Mine Betul,Okay, Tufan Can The Korean Academy of Prosthodonitics 2013 The Journal of Advanced Prosthodontics Vol.5 No.3

PURPOSE. Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts. MATERIALS AND METHODS. The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (${\alpha}$=.05). RESULTS. Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group. CONCLUSION. Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.

Accuracy of virtual models in the assessment of maxillary defects

Kamburoglu, Kivanc,Kursun, Sebnem,Kilic, Cenk,Ozen, Tuncer Korean Academy of Oral and Maxillofacial Radiology 2015 Imaging Science in Dentistry Vol.45 No.1

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. Materials and Methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) $60{\times}60mm$ FOV, $0.125mm^3$ ($FOV_{60}$); 2) $80{\times}80mm$ FOV, $0.160mm^3$ ($FOV_{80}$); and 3) $100{\times}100mm$ FOV, $0.250mm^3$ ($FOV_{100}$). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

Effects of various cone-beam computed tomography settings on the detection of recurrent caries under restorations in extracted primary teeth

Kamburoglu, Kivanc,Sonmez, Gul,Berktas, Zeynep Serap,Kurt, Hakan,Ozen, Dogukan Korean Academy of Oral and Maxillofacial Radiology 2017 Imaging Science in Dentistry Vol.47 No.2

Purpose: The aim of this study was to assess the ex vivo diagnostic ability of 9 different cone-beam computed tomography (CBCT) settings in the detection of recurrent caries under amalgam restorations in primary teeth. Materials and Methods: Fifty-two primary teeth were used. Twenty-six teeth had dentine caries and 26 teeth did not have dentine caries. Black class II cavities were prepared and restored with amalgam. In the 26 carious teeth, recurrent caries were left under restorations. The other 26 intact teeth that did not have caries served as controls. Teeth were imaged using a $100{\times}90-mm$ field of view and a 0.2-mm voxel size with 9 different CBCT settings. Four observers assessed the images using a 5-point scale. Kappa values were calculated to assess observer agreement. CBCT settings were compared with the gold standard using a receiver operating characteristic analysis. The area under the curve (AUC) values for each setting were compared using the chi-square test, with a significance level of ${\alpha}=.05$. Results: Intraobserver kappa values ranged from 0.366 to 0.664 for observer 1, from 0.311 to 0.447 for observer 2, from 0.597 to 1.000 for observer 3, and from 0.869 to 1 for observer 4. Furthermore, interobserver kappa values among the observers ranged from 0.133 to 0.814 for the first reading and from 0.197 to 0.805 for the second reading. The highest AUC values were found for setting 5 (0.5916) and setting 3 (0.5886), and were not found to be statistically significant(P>.05). Conclusion: Variations in tube voltage and tube current did not affect the detection of recurrent caries under amalgam restorations in primary teeth.

Carcinoma of the Tongue: A Case-control Study on Etiologic Factors and Dental Trauma

Bektas-Kayhan, Kivanc,Karagoz, Gizem,Kesimli, Mustafa Caner,Karadeniz, Ahmet Nafiz,Meral, Rasim,Altun, Musa,Unur, Meral Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Background: Carcinoma of the tongue is the most common intra-oral malignancy in Western countries. Incidence and mortality rates have increased in recent years, and survival has not improved. This study aimed to determine etiologic factors for tongue cancer with age-sex matched case-control data. Materials and Methods: 47 patients with carcinoma of the tongue referred to our oral medicine clinic between years 2005-2006 were analyzed and compared with control group data. The medical records, including family history of cancer, dental trauma, and history of abuse of alcohol and tobacco products was recorded for all subjects. Chi square comparison tests and linear regression analysis were performed using the SPSS program for statistics. Results: Patient and randomly selected control groups each consisted of 30 male and 17 female subjects with mean ages 53.2 (${\pm}12.6$) and 52.6 (${\pm}11.5$) years respectively. Smoking and alcohol abuse proportions were significantly higher in the patient group (p=0.0001, p<0.0001 respectively). Chronic mechanical trauma was observed in 44.7% of the patients and 17.0% of the control group (p=0.004). Similarly, family history of cancer of any type (for the first degree relatives) was found to be more common in the patient group (p=0.009). On regression analysis, alcohol abuse, family history of cancer, smoking, chronic mechanical traumas appeared as significant etiologic factors (p=0.0001). Conclusions: We believe that field cancerization may become evident in oral and oropharyngeal mucosa with multiple steps of molecular changes starting from the first sign of dysplasia with chronic exposure to etiological factors. Chronic trauma cases need particular attention to search for very early signs of cancer.

Is the MDR1 C3435T Polymorphism Responsible for Oral Mucositis in Children with Acute Lymphoblastic Leukemia?

Bektas-Kayhan, Kivanc,Kucukhuseyin, Ozlem,Karagoz, Gizem,Unur, Meral,Ozturk, Oguz,Unuvar, Aysegul,Devecioglu, Omer,Yilmaz-Aydogan, Hulya Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10

Background and Aim: Although the functional consequences of MDR-1 polymorphisms have been the subject of numerous studies, to the best to our knowledge, associations with clinical side effects of anticancer drugs have yet to be assessed. Our aim was to clarify any role of the C3435T polymorphism of the MDR1 gene in oral mucositis and its relation with elevated reactive oxygen species (ROS) levels, in children with acute lymphoblastic leukemia (ALL). Materials and Methods: The distribution of the MDR-1 C3435T polymorphism in 47 patients with ALL was determined by RFLP and compared with that of 68 healthy controls. Results: There were no association in distribution of genotypes of MDR-1 C3435T polymorphism and the risk of ALL. Oral mucositis were detected in 78.7% (n=37) of the patients and significantly related to the MDR-1 CT genotype (p=0.042), as confirmed by logistic regression analysis. Conclusion: Our preliminary data suggest that children carrying the CT genotype are more prone to develop oral mucositis, which might mean that the heterozygous genotype leads to accumulation of more reactive oxygen species. Since a limited number of patients was investigated, further studies are needed to confirm these findings.

Comparison of Short-Segment Pedicle Instrumentation with Supplemental Hook Fixation under Axial Compression in Relation to Graft Positioning and Posterior Ligamentous Integrity: A Biomechanical Study on the Calf Spine

Muratli Sedit Kivanc,Berk Haluk 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.1

Study Design: Biomechanical study.Purpose: This study investigates the benefits of supplemental hook fixation (SHF) on short-segment pedicle instrumentation (SSPI) in relation to anterior strut graft positioning. In addition, it seeks to determine whether the integrity of the posterior ligamentous complex (PLC) affects the stability of the spinal construct.Overview of Literature: Implant and/or bone failure with progressive kyphotic deformity after SSPI is common. To prevent this, several approaches are available, including SHF, anterior strut grafting, use of longer spinal constructs, and extension of the fusion to additional adjacent segments.Methods: A total of eight calf spines were instrumented with SSPI (n=4) and SHF (n=4) with strain gauges on the implants. Strain measurements were performed under axial compression in the following order: intact spine, corpectomy, ventral positioned strut grafting, posterior positioned strut grafting, ventral positioned grafting with resected PLC, and corpectomy with resected PLC.Results: The SHF group showed slightly lower strain values than SSPI in instrumented corpectomy-only specimens, but there were no statistically significant differences between them (p >0.05). The SHF group was significantly more stable than SSPI when strut grafting is employed, regardless of the location of the grafts (p =0.000). In the SSPI group, ventral positioning of the graft contributed significantly to the stability (p =0.000). There was no statistically significant difference between the ventral or posterior positioning of the graft in the SHF group (p =0.187). In addition, the integrity of the PLC did not affect stability in either group (p >0.005).Conclusions: Although not statistically significant, our investigation demonstrated that the most stable method was the SHF along with ventral positioned strut graft. However, if the SSPI is the treatment of choice, ventral positioned strut graft support will be useful in minimizing the risk of implant failure and progressive kyphotic deformity.

Effect of different voxel sizes on the accuracy of CBCT measurements of trabecular bone microstructure: A comparative micro-CT study

Tayman, Mahmure Ayse,Kamburoglu, Kivanc,Ocak, Mert,Ozen, Dogukan Korean Academy of Oral and Maxillofacial Radiology 2022 Imaging Science in Dentistry Vol.52 No.2

Purpose: The aim of this study was to assess the accuracy of cone-beam computed tomographic (CBCT) images obtained using different voxel sizes in measuring trabecular bone microstructure in comparison to micro-CT. Materials and Methods: Twelve human skull bones containing posterior-mandibular alveolar bone regions were analyzed. CBCT images were obtained at voxel sizes of 0.075mm(high: HI) and 0.2mm(standard: Std), while microCT imaging used voxel sizes of 0.06 mm (HI) and 0.12 mm (Std). Analyses were performed using CTAn software with the standardized automatic global threshold method. Intraclass correlation coefficients were used to evaluate the consistency and agreement of paired measurements for bone volume (BV), percent bone volume (BV/TV), bone surface (BS), trabecular thickness (TbTh), trabecular separation (TbSp), trabecular number (TbN), trabecular pattern factor(TbPf), and structure model index (SMI). Results: When compared to micro-CT, CBCT images had higher BV, BV/TV, and TbTh values, while micro-CT images had lower BS, TbSp, TbN, TbPf, and SMI values (P<0.05). The BV, BV/BT, TbTh, and TbSp variables were higher with Std voxels, whereas the BS, TbPf, and SMI variables were higher with HI voxels for both imaging methods. For each imaging modality and voxel size evaluated, BV, BS, and TbTh were significantly different(P<0.05). TbN, TbPf, and SMI showed statistically significant differences between imaging methods(P<0.05). The consistency and absolute agreement between micro-CT and CBCT were excellent for all variables. Conclusion: This study demonstrated the potential of high-resolution CBCT imaging for quantitative bone morphometry assessment.

Comparison of micro-computerized tomography and cone-beam computerized tomography in the detection of accessory canals in primary molars

Acar, Buket,Kamburoglu, Kivanc,Tatar, Ilkan,Arikan, Volkan,Celik, Hakan Hamdi,Yuksel, Selcen,Ozen, Tuncer Korean Academy of Oral and Maxillofacial Radiology 2015 Imaging Science in Dentistry Vol.45 No.4

Purpose: This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Materials and Methods: Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. Results: The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images. Conclusion: Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

Assessment of endodontically treated teeth by using different radiographic methods: an ex vivo comparison between CBCT and other radiographic techniques

Demiralp, Kemal Ozgur,Kamburoglu, Kivanc,Gungor, Kahraman,Yuksel, Selcen,Demiralp, Gokcen,Ucok, Ozlem Korean Academy of Oral and Maxillofacial Radiology 2012 Imaging Science in Dentistry Vol.42 No.3

Purpose: To compare different radiographic methods for assessing endodontically treated teeth. Materials and Methods: Root canal treatments were applied in 120 extracted mandibular teeth, which were divided into four groups: (1) ideal root canal treatment (60 teeth), (2) insufficient lateral condensation (20 teeth), (3) root canals filled short of the apex (20 teeth), (4) overfilled root canal treatment (20 teeth). The teeth were imaged using intraoral film, panoramic film, digital intraoral systems (CCD and PSP), CCD obtained with portable X-ray source, digital panoramic, and CBCT images obtained at 0.3 $mm^3$ and 0.2 $mm^3$ voxel size. Images were evaluated separately by three observers, twice. Kappa coefficients were calculated. The percentage of correct readings obtained from each modality was calculated and compared using a t-test (p<0.05). Results: The intra-observer kappa for each observer ranged between 0.327 and 0.849. The inter-observer kappa for each observer for both readings ranged between 0.312 and 0.749. For the ideal root canal treatment group, CBCT with 0.2 $mm^3$ voxel images revealed the best results. For insufficient lateral condensation, the best readings were found with periapical film followed by CCD and PSP. The assessment of teeth with root canals filled short of the apex showed the highest percentage of correct readings by CBCT and CCD. For the overfilled canal treatment group, PSP images and conventional periapical film radiographs had the best scores. Conclusion: CBCT was found to be successful in the assessment of teeth with ideal root canal treatment and teeth with canals filled short of the apex.