21241 research outputs found
Sort by
SOME PHYSICAL AND MECHANICAL PROPERTIES OF PARTICLE BOARDS PRODUCED WITH HAZELNUT HUSK AND
Full text linkIn this study, under laboratory conditions, hazelnut husk and astragalus plant were mixed separately into black pine wood chips, and multi-purpose boards were produced from the obtained chips with urea formaldehyde glue. After the hazelnut husk and astragalus plant were dried and ground, they were added to the chip and glue mixture in certain proportions. Hazelnut husk mixture ratios were applied as 100 %; 0 %, 75 %; 25 %, 50 %; 50 %, 25 %; 75 %, 0 %; 100 % to black pine wood chip in the particle board mixture. These ratios were made in the same way for the astragalus plant. From these mixtures, chipboard blanks of 16 mm thickness and densities between 0,68 g/cm3 and 0,72 g/cm3 were produced. Density, moisture content, thickness increase, water intake, bending strength, modulus of elasticity in bending and tensile strength perpendicular to the surface were tested in physical and mechanical experiments. According to the results obtained, as the participation rate of hazelnut shells and astragalus increased, the durability properties of the panels decreased. At the same time, it shows that the technological properties of the panels produced by adding up to 25 % astragalus plant and hazelnut shells to the mixture comply with the standards
Genetic diversity and marker-trait associations among Çakıldak hazelnut (Corylus avellana L.) clones in the North Eastern Anatolia of Türkiye based on morphological and molecular markers
Full text linkThe study was conducted to determine the yield, nut traits, genetic diversity, and marker-trait associations in promising and phenotypically different & Ccedil;ak & imath;ldak hazelnut clones selected from Fatsa (Ordu) region, Eastern Black Sea Region. In clones, nut weight, kernel weight, and kernel ratio ranged from 1.48 to 1.97 g, 0.82-1.12 g, and 49.6-58.2%, respectively. Nut yield per plant varied between 174.5 and 543.5 g with a yield efficiency ranging from 1.91 to 13.79 g cm-2. In the molecular analysis, 12 ISSR (Inter Simple Sequence Repeat) and 3 SRAP (Sequence-related Amplified Polymorphism) primers generated 95 bands, of which 85 were polymorphic. The polymorphism rate was in the range of 50-100%. The similarity index ranged from 0.59 to 0.96. & Ccedil;ak & imath;ldak clones were grouped into three clusters in STRUCTURE similar to the UPGMA (unweighted pair group method with arithmetic mean). In the association mapping by ISSR/SRAP markers, 65 loci were related to the traits. Some crucial yield and nut traits important for hazelnut breeding were associated with pleiotropic loci [(GAA)6-600 and (AG)7YC-400, respectively], which could help breeders to select superior individuals in terms of yield and nut traits. & Ccedil;-1, & Ccedil;-6, and & Ccedil;-9 clones were genetically different and superior in terms of yield and nut traits, can be used as decent genetic materials for developing new cultivars in hazelnut breeding programs. These results may also contribute to the conservation and maintenance of hazelnut genetic resources, and the future hazelnut breeding efforts.Scientific Research Projects Coordination Unit of Ordu University [BY-1806]This study was supported by the Scientific Research Projects Coordination Unit of Ordu University with project number BY-1806. The authors thank also Dr. Emrah Gueler for the statistical analysis and for his syntactic corrections of the manuscript
A novel methodological approach to SaaS churn prediction using whale optimization algorithm
Full text linkCustomer churn is a critical concern in the Software as a Service (SaaS) sector, potentially impacting long-term growth within the cloud computing industry. The scarcity of research on customer churn models in SaaS, particularly regarding diverse feature selection methods and predictive algorithms, highlights a significant gap. Addressing this would enhance academic discourse and provide essential insights for managerial decision-making. This study introduces a novel approach to SaaS churn prediction using the Whale Optimization Algorithm (WOA) for feature selection. Results show that WOA-reduced datasets improve processing efficiency and outperform full-variable datasets in predictive performance. The study encompasses a range of prediction techniques with three distinct datasets evaluated derived from over 1,000 users of a multinational SaaS company: the WOA-reduced dataset, the full-variable dataset, and the chi-squared-derived dataset. These three datasets were examined with the most used in literature, k-nearest neighbor, Decision Trees, Na & iuml;ve Bayes, Random Forests, and Neural Network techniques, and the performance metrics such as Area Under Curve, Accuracy, Precision, Recall, and F1 Score were used as classification success. The results demonstrate that the WOA-reduced dataset outperformed the full-variable and chi-squared-derived datasets regarding performance metrics
A Two-Stage Optimal Electric Vehicles Charging Methodology Based on Aggregators Considering Grid Reliability and Operational Efficiency
Full text linkThis paper presents a two-stage optimal charging methodology for electric vehicles that considers grid impact, load management, and optimal charging based on pricing. The charging method is distributed based on aggregators (complying with orders such as FERC 2222). The approach considers peak loading time and optimally schedules charging so that cost savings can be integrated into customer pricing as incentives. The advantages of this proposed architecture include a) demand response and maintaining load balance, b) supporting grid stability, and c) allowing prioritized charging. It is observed that the approach has significant improvement in cost saving, valley filling, and fully providing the EV charging requirements for the customers
Cerebral blood flow differences in cognitive disengagement syndrome and attention deficit hyperactivity disorder: Doppler ultrasonography findings
Full text linkObjective: The present study aims to investigate potential differences in cerebral blood flow between children with Cognitive Disengagement Syndrome (CDS) and those with Attention Deficit Hyperactivity Disorder (ADHD) using Doppler ultrasound. Methods: In this single-center prospective study, we included 24 cases in the ADHD group with CDS symptoms, 29 cases in the ADHD group without CDS symptoms and, 26 children in the healthy controls. The children ranged in age from 6 to 15. Participants were evaluated by diagnostic interviews and standardized measures. Doppler ultrasound was performed to measure peak systolic velocity and blood flow volume (BFV) in the internal carotid (ICA) and vertebral arteries for each participant. Results: The right ICA and total ICA BFVs were significantly lower in the CDS group compared to the ADHD and control groups (p = 0.007 and p = 0.003, respectively). In addition, there was a weak negative correlation between right ICA BFV and CDS scores, suggesting a possible link between reduced cerebral blood flow and CDS symptom severity. Conclusion: This study provides a noteworthy starting point for research on the neurovascular basis of CDS. Our findings indicated significant differences in cerebral blood flow between CDS and ADHD, supporting the idea that CDS is a unique attentional disorder with distinct neurobiological characteristics from ADHD
Three Different Involvements in a Case of Ulcerative Colitis: Bilateral Femoral Head Avascular Necrosis, Spondylodiscitis and Spondyloarthropathy
Full text linkAvascular necrosis (AVN) is a serious condition that develops as a result of inadequate blood supply to bone tissue. This condition is usually associated with trauma, long-term steroid use, or systemic diseases. Spondylodiscitis is a serious infection affecting the spinal discs and vertebral bodies and is usually of bacterial origin. The association of spondylodiscitis and avascular necrosis is rare. In this case report, bilateral femoral head avascular necrosis and spondylodiscitis coexistence in a 53-year-old female patient diagnosed with ulcerative colitis is discussed. This case aims to emphasize the risk of developing AVN and spondylodiscitis in patients with chronic inflammatory disease who receive longterm corticosteroid treatment
The Mediating Role of Life Satisfaction in the Relationship between the Lifelong Learning Tendencies of Teachers and Their Attitudes toward Teaching
Full text linkThis study investigates whether life satisfaction serves as a mediator in the relationship between the lifelong learning tendencies of teachers and their professional attitudes toward teaching. The sample of the study comprised 361 teachers, and data were collected using instruments measuring tendencies toward lifelong learning, attitudes toward the profession of teaching, and overall life satisfaction. The data were analyzed using the IBM SPSS Version 27 and Process Macro 4.1 programs, employing independent-samples t-tests, Pearson’s correlation analyses, and mediation analysis models. There were significant positive relationships among lifelong learning, life satisfaction, and professional attitudes. Female teachers demonstrated a higher tendency toward lifelong learning than male teachers, consistent with previous research suggesting women are more inclined toward self-improvement. However, no significant gender-based differences were observed in life satisfaction, indicating that professional satisfaction may be shaped more by individual experiences than by gender. Furthermore, life satisfaction was identified as a mediator, suggesting that teachers with high lifelong learning tendencies and life satisfaction levels displayed more positive professional attitudes. These results underscored the importance of promoting lifelong learning and the well-being of teachers to enhance job satisfaction and commitment. Educational policymakers are encouraged to develop structured lifelong learning programs and wellness initiatives to support the professional growth of teachers. © 2025 Elsevier B.V., All rights reserved
Kelime tanıma etkinlikleriyle yapılan ilk okuma yazma öğretiminin farklı okuryazarlık becerilerine etkisi The effect of literacy teaching with word recognition activities on different literacy skills
Full text linkBu araştırmanın amacı, okuma yazma öğretimi sürecinde ilkokul birinci sınıf öğrencileriyle gerçekleştirilen kelime tanıma etkinliklerinin finansal, görsel ve eleştirel okuryazarlık becerilerine etkisini incelemektir. Araştırmanın çalışma grubu, Düzce ilinde öğrenim gören 80 ilkokul birinci sınıf öğrencisinden oluşmaktadır. Araştırmada ön test ve son test kontrol gruplu yarı deneysel araştırma deseni tercih edilmiştir. Araştırmada uygulamalar 10 hafta sürmüştür. Araştırmada veriler, resimli şekilde hazırlanan finansal, görsel ve eleştirel okuryazarlık kavram testleri ve finansal, görsel ve eleştirel okuryazarlık ölçekleri kullanılarak toplanmıştır. Araştırmada ön testte deney ve kontrol grupları arasında finansal, görsel ve eleştirel okuryazarlık boyutları yönünden anlamlı düzeyde farklılık olmadığı görülmüştür. Deney ve kontrol grupları son test resimli okuryazarlık kavram testi puanları yönünden karşılaştırıldığında finansal ve eleştirel okuryazarlık türünde anlamlı fark ortaya çıkmazken, görsel okuryazarlık türünde kontrol grubu lehine anlamlı fark ortaya çıkmıştır. Diğer araştırma bulgusunda, deney grubu öğrencilerinin resimli finansal, görsel ve eleştirel okuryazarlık kavram testleri ön test ve son test puanları arasında deney grubu lehine anlamlı farklılık olduğu ortaya çıkmıştır. Elde edilen diğer sonuçlar doğrultusunda, resimli finansal, görsel ve eleştirel okuryazarlık kavram testlerinde ortaya çıkan sonuçlarla finansal, görsel ve eleştirel okuryazarlık ölçeklerinden alınan sonuçların birbirini desteklediği görülmektedir. Ortaya çıkan sonuçlardan hareketle, araştırmacılara birinci sınıf öğrencilerine uygun okuryazarlık ölçekleri geliştirmeleri, öğretmenlere kelime tanıma etkinlikleriyle okuryazarlık becerilerini ilişkilendirmeleri ve ebeveynlere ise çocukların okuryazarlık becerilerini desteklemeleri önerilmektedir
Visceral and Dysfunctional Adiposity Indices as Predictors of Insulin Resistance and Metabolic Syndrome in Women with Polycystic Ovary Syndrome: A Cross-Sectional Study
Full text linkBackground and Objectives: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age. Women with PCOS often have metabolic disorders such as insulin resistance (IR), type 2 diabetes (T2DM), obesity, and metabolic syndrome (MetS). The assessment of visceral adiposity and dysfunctional adipose tissue is crucial for understanding the metabolic risks associated with PCOS. The visceral adiposity index (VAI) and the dysfunctional adiposity index (DAI) are two novel metabolic indices that more specifically assess adipose tissue dysfunction and visceral fat accumulation. This study aimed to evaluate the clinical utility of VAI and DAI as predictive markers for metabolic complications such as insulin resistance (IR) and metabolic syndrome (MetS) in women with PCOS. Materials and Methods: This cross-sectional study included 92 women diagnosed with PCOS based on the 2023 revised Rotterdam criteria, as well as 68 healthy controls. Anthropometric and biochemical parameters, including fasting glucose, insulin, lipid profile, and hormonal markers, were recorded. VAI and DAI were calculated using established formulas derived from previous validated studies. Results: The mean VAI in PCOS patients was 4.26 +/- 3.23, compared to 2.61 +/- 1.92 in controls (p = 0.003). The mean DAI in PCOS patients was 3.00 +/- 1.86, while in controls it was 1.86 +/- 1.22 (p = 0.003). Both VAI (Area Under the Curve [AUC] = 0.639) and DAI (AUC = 0.635) did not demonstrate statistically significant diagnostic performance for PCOS itself, but they were strongly associated with metabolic disturbances within the PCOS group. VAI and DAI values were significantly elevated in PCOS patients with IR (p < 0.001) and MetS (p < 0.001). For MetS in PCOS patients, VAI demonstrated the highest predictive ability, with an AUC of 0.87 and a cutoff of 4.73 (sensitivity 62%, specificity 92%), while DAI had an AUC of 0.86 with a cutoff of 2.44 (sensitivity 74%, specificity 80%). Regarding IR in PCOS patients, VAI had an AUC of 0.75 with a cutoff of 2.56 (sensitivity 82%, specificity 56%), while DAI had an AUC of 0.74 with a cutoff of 1.59, showing a sensitivity of 82% and a specificity of 55%. Conclusions: Although VAI and DAI are not suitable for diagnosing PCOS, they provide valuable insights into the metabolic risks associated with the condition. VAI and DAI can serve as promising biomarkers for identifying IR and MetS risk in women with PCOS. Their integration into clinical practice may facilitate the early detection of cardiometabolic complications, offering a more specific metabolic risk assessment compared to traditional anthropometric measures
Investigation of the Effects of Cutting Tool Coatings and Machining Conditions on Cutting Force, Specific Energy Consumption, Surface Roughness, Cutting Temperature, and Tool Wear in the Milling of Ti6Al4V Alloy
Full text linkThe present study aims to investigate the effects of cutting parameters (cutting speed, Vc: 60-90-120 m/min; feed rate, f: 0.055-0.085-0.115 mm/rev), cutting tool coatings (CVD: TiN/TiCN/Al2O3 and PVD: TiAlN), and machining conditions (dry, air, and MQL) on cutting force (Fc), specific energy consumption (SEC), surface roughness (Ra), cutting temperature (T), and tool wear (Vb) during the milling of Ti6Al4V alloy. As a result, it was observed that all machining tests conducted with the Al2O3-coated cutting tool showed improvements of 4.7%, 10.75%, 3.8%, and 6.3% in Fc, SEC, Ra, and T, respectively, compared to the tests performed with the TiAlN-coated cutting tool. Under dry machining conditions, the average Fc, SEC, Ra, and T values were 302.82 N, 4.88 j/mm3, 0.653 mu m, and 241.06 degrees C, respectively. Compared to dry machining conditions, the air and MQL machining conditions demonstrated improvements in the average Fc by 5.15% and 6.3%, SEC by 10.27% and 17.79%, Ra by 6.23% and 11.17%, and T by 8.9% and 19.68%, respectively. The lowest Fc and Ra values for the Al2O3-coated cutting tool were measured at 228.33 N and 0.402 mu m, respectively, under the MQL machining condition, at a cutting speed of 120 m/min and a feed rate of 0.055 mm/rev. The lowest SEC value (2.694 J/mm3) was also obtained using the Al2O3-coated tool under MQL conditions at a cutting speed of 120 m/min and a feed rate of 0.115 mm/rev. Similarly, the lowest cutting temperature (129 degrees C) was achieved with the Al2O3-coated tool under MQL conditions at a cutting speed of 60 m/min and a feed rate of 0.055 mm/rev. The wear performance of the Al2O3-coated cutting tool was observed to be superior to that of the TiAlN-coated tool