The Effect of Hf Addition on the Boronizing and Siliciding Behavior of CoCrFeNi High Entropy Alloys

The effect of a boronizing and siliciding process on CoCrFeNiHf0.1–0.42 high entropy alloys was examined in this study. When increasing the amount of added Hf in CoCrFeNiHfx, the structure of the alloys gradually transformed from single-phase FCC to firstly Ni7Hf2 + FCC, and finally to C15 Laves and FCC phases. The boronizing/siliciding process resulted in the formation of a silicon-rich layer and a boride layer (BL). Increasing the amount of Hf in the alloys resulted in a decrease in the combined layer thickness, which was measured for CoCrFeNi, CoCrFeNiHf0.1, CoCrFeNiHf0.2, and CoCrFeNiHf0.42 to be 70 \ub5m, 63 \ub5m, 20 \ub5m, and 15 \ub5m, respectively. In contrast, the thickness of the transition zone/diffusion zone increased with more Hf in the alloys. While silicon atoms were gathered close to the BL, they were not transferred into the CoCrFeNi substrate. In contrast to the observation for CoCrFeNi, Si atoms penetrated through the Ni-rich phase (Ni7Hf2) in the CoCrFeNiHfx alloys. Furthermore, the Cr-B rich area (Cr5B3) in the coating limited the transport of Si into the CoCrFeNiHfx substrates. XRD analysis showed that the BL contained Ni2Si, FeB, Fe2B, Co2B, and Cr5B3 phases

Bulanık karar ortamında karınca kolonisi optimizasyonu yöntemiyle araç rotalama

Many companies use fleets of vehicles within their activity in a range of sectors. More often than not, meeting customers' requirements, taking into account their geographical spread and delivery time windows, as well as managing the company's operating and financial constraints, turns into a nightmare. The vehicle routing problem with time windows (VRPTW) is a well-known and complex combinatorial optimization problem concerned with finding efficient routes, beginning and ending at a central depot, for a fleet of identical vehicles to serve a number of customers with capacity and time window constraints where each customer is visited exactly once by a vehicle. The capacity constraint signifies that the total load on a route cannot exceed the capacity of the assigned vehicle. The time window constraint signifies that each vehicle must start the service each customer in the period specified by the customer. The objective is to find the feasible solution (hierarchically or not) with minimal number of vehicles or with the minimal total distance. VRPTW has been a subject of intensive research focused mainly on the heuristic and the metaheuristic approaches. The VRPTW is still one of the most difficult problems in combinatorial optimization and this problem contributes directly to a real opportunity to reduce costs in the important area of logistics. Transportation management, and more specifically the vehicle routing, has a considerable economical impact on all logistic systems. However, the classical definitions of the vehicle routing problem often lack handling of uncertain parameters and flexible constraints such as the traveling times between customers and the latest delivery times for the custoners. In addition, a best/optimal solution generated by a heuristic/exact method, for the classical VRPTW do not mean any knowledge to the user about its realization when applicated. Whereas, the solutions generated with the classical models usually became infeasible when implemented and the planners are often involved to make corrections by hand. The natural approach to modeling the uncertainty is a stochastic one. Unfortunately, the stochastic models are often hard to solve. Moreover, it may be hard or expensive to assume any speci?c probability distributions for the unknown parameters. For these reasons stochastic models are behind the needs of users. Up to past decades, operational research methods seem to be inadequate for the large sized combinatorial optimization problems due to their large computational effort and long solution time. But, recent developments in data processing and communication technologies and recently proposed metaheuristic methods that can generate solutions to large sized combinatorial problems made these classical disadvantages less important for the researchers. Subsequently, validity of used models became a more important issue for the researchers. In this study, the fuzzy set and the possibility theories are utilized in order to propose a fuzzy robust programming model for the VRPTW that can be used in the uncertain decision environments. The fuzzy programming model proposed in this study exploit fuzzy sets and fuzzy intervals in order to model flexibilities on latest delivery times and uncertainties for traveling times between customers. A necessity measure is used to generate knowledge about the satisfaction of delivery time constraints when a route is realized by the vehicle. In addition, a possibility measure is used to evaluate the customer satisfaction levels. Using the necessity and the possibility measures, solutions that have the maximum risk level to be unfeasible and the minimum customer satisfaction, which are specified by the user, can be generated. Validities of the models are increased while decreasing the computational effort with fuzzy programming models. In order to generate solutions for the proposed model an ant colony optimization based algorithm is developed. The algorithm is capable of solving both the classical and the fuzzy programming models for the VRPTW. Results of the experimental studies with the benchmark problems indicate that the proposed fuzzy programming model and the ant colony optimization algorithm can be usable for solving practical problems in means of solution time and quality. The proposed approach can be integrated with a decision support system in order to generate alternative solutions achieving the planners' and the customers' preferences along with acquiring more information about the realization of the solutions. Keywords: Fuzzy sets, possibility theory, vehicle routing problem, ant colony optimization. Bu çalışmada, bulanık kümeler ve olabilirlik teorilerinden faydalanılarak zaman aralıklı araç rotalama problemi (ZAARP) için bulanık karar ortamında kullanılabilecek bir gürbüz bulanık programlama modeli önerilmiştir. Geçmiş çalışmalar incelendiğinde ZAARP'nin genellikle parametrelerindeki belirsizliklerin ve kısıtlarındaki esnekliklerin göz ardı edilerek modellendiği görülmüştür. Bu tip modellere üretilen çözümler uygulama aşamasında çoğunlukla geçerliliklerini yitirmekte ve kullanıcılar tarafından elle düzeltilmeyi gerektirmektedirler. Stokastik modellerin kullanıldığı çalışmalarda ise önerilen modellerin çok fazla hesaplama yükü gerektirdiği ve parametrelerinin belirlenmesi için problemle ilgili geçmiş verilere ihtiyaç duyulduğu görülmektedir. Bu nedenlerle stokastik modeller de gerçek hayatta karşılaşılan problemlerin çözümünde rahatlıkla kullanılamamaktadır. Bu çalışmada belirsizliklerin ve esnekliklerin modellenmesi için bulanık aralıklar ve bulanık kümeler kullanılmıştır. Gereklilik ve olabilirlik ölçütleri ile planlayıcının belirlediği eşik güvenilirlik ve müşteri tatmini düzeylerine sahip çözümler oluşturulmuştur. Bulanık programlama modeli ile yüksek veri işleme maliyeti düşürülürken modellerin geçerlilikleri de arttırılmıştır. Önerilen modellere çözüm oluşturmak amacıyla karınca kolonisi optimizasyonu tabanlı bir algoritma geliştirilmiştir. Bulanık değerler kesin değerlerin genelleştirilmiş hali olarak ele alındığından geliştirilen algoritma kesin veri ve/veya bulanık veri durumlarında çözüm oluşturabilmektedir. Örnek problemler üzerinde gerçekleştirilen deneylerde planlayıcıların tercih ve önceliklerine göre alternatif çözümlerin üretilebileceği ve oluşturulan çözümler hakkında planlayıcılara ve müşterilere daha fazla bilgi sağlanabileceği gösterilmiştir. Anahtar Kelimeler: Bulanık kümeler, olabilirlik teorisi, araç rotalama problemi, karınca kolonisi optimizasyonu

Juniperus L. for Restoration of Degraded Forest Lands in Turkey

Degraded forests are among of the most important environmental and commercial problems around the world. Turkey has 22.74 million hectares of forest area, out of which 9.656 million ha (42%) are unproductive. To transform these unproductive forests into productive ones, forest restoration including rehabilitation is one of the best actions. In this sense, juniper species play an important role for degraded lands because they are drought-tolerant and withstand aridity and poor soils better than most timber species grown in Turkey. Therefore, this review presents the ecological considerations for the restoration of degraded forest lands in Turkey under the conditions of climate change. Within this framework, it focuses on the production of planting stock of juniper species, the significance of site-species matching, and post-planting site maintenance for successful rehabilitation

ADEA Claimant Can Retain Severance Payments and Sue Former Employer

Former employees can maintain claims under the Age Discrimination in Employment Act (ADEA) without first repaying the consideration received for an invalid release of claims. The Supreme Court\u27s pronouncement, Oubre v. Entergy Operations, Inc., 1988 U.S. Lexis 646 (Jan. 26, 1998), may change the way many employers negotiate and execute severance packages and settlements with terminated employees

The marine arthropods of Turkey

This recent checklist of marine arthropods found on the coasts of Turkey represents a total of 1531 species belonging to 7 classes: Malacostraca (766 species), Maxillopoda (437 species), Ostracoda (263 species), Pycnogonida (27 species), Arachnida (26 species), Branchiopoda (7 species), and Insecta (5 species). Seventy-fve species were classifed as alien species in the region. Tis paper also includes the frst record of the amphipod Melita valesi from the Levantine coast of Turkey (Kaş, Gulf of Antalya).This recent checklist of marine arthropods found on the coasts of Turkey represents a total of 1531 species belonging to 7 classes: Malacostraca (766 species), Maxillopoda (437 species), Ostracoda (263 species), Pycnogonida (27 species), Arachnida (26 species), Branchiopoda (7 species), and Insecta (5 species). Seventy-fve species were classifed as alien species in the region. Tis paper also includes the frst record of the amphipod Melita valesi from the Levantine coast of Turkey (Kaş, Gulf of Antalya)

Efficacy of subsequent treatments in patients with hormone-positive advanced breast cancer who had disease progression under CDK 4/6 inhibitor therapy

Background: There is no standard treatment recommended at category 1 level in international guidelines for subsequent therapy after cyclin-dependent kinase 4/6 inhibitor (CDK4/6) based therapy. We aimed to evaluate which subsequent treatment oncologists prefer in patients with disease progression under CDKi. In addition, we aimed to show the effectiveness of systemic treatments after CDKi and whether there is a survival difference between hormonal treatments (monotherapy vs. mTOR-based). Methods: A total of 609 patients from 53 centers were included in the study. Progression-free-survivals (PFS) of subsequent treatments (chemotherapy (CT, n:434) or endocrine therapy (ET, n:175)) after CDKi were calculated. Patients were evaluated in three groups as those who received CDKi in first-line (group A, n:202), second-line (group B, n: 153) and ≥ 3rd-line (group C, n: 254). PFS was compared according to the use of ET and CT. In addition, ET was compared as monotherapy versus everolimus-based combination therapy. Results: The median duration of CDKi in the ET arms of Group A, B, and C was 17.0, 11.0, and 8.5 months in respectively; it was 9.0, 7.0, and 5.0 months in the CT arm. Median PFS after CDKi was 9.5 (5.0–14.0) months in the ET arm of group A, and 5.3 (3.9–6.8) months in the CT arm (p = 0.073). It was 6.7 (5.8–7.7) months in the ET arm of group B, and 5.7 (4.6–6.7) months in the CT arm (p = 0.311). It was 5.3 (2.5–8.0) months in the ET arm of group C and 4.0 (3.5–4.6) months in the CT arm (p = 0.434). Patients who received ET after CDKi were compared as those who received everolimus-based combination therapy versus those who received monotherapy ET: the median PFS in group A, B, and C was 11.0 vs. 5.9 (p = 0.047), 6.7 vs. 5.0 (p = 0.164), 6.7 vs. 3.9 (p = 0.763) months. Conclusion: Physicians preferred CT rather than ET in patients with early progression under CDKi. It has been shown that subsequent ET after CDKi can be as effective as CT. It was also observed that better PFS could be achieved with the subsequent everolimus-based treatments after first-line CDKi compared to monotherapy ET.Breast Cancer Consortiu

Trends in distance education research: A content analysis of journals 2009-2013

This study intends to explore the current trends in the field of distance education research during the period of 2009-2013. The trends were identified by an extensive review of seven peer reviewed scholarly journals: The American Journal of Distance Education (AJDE), Distance Education (DE), The European Journal of Open, Distance and e-Learning (EURODL), The Journal of Distance Education (JDE), The Journal of Online Learning and Technology (JOLT), Open Learning: The Journal of Open, Distance and e-Learning (OL) and The International Review of Research in Open and Distributed Learning (IRRODL). A total of 861 research articles was reviewed. Mainly content analysis was employed to be able to analyze the current research. Also, a social network analysis (SNA) was used to interpret the interrelationship between keywords indicated in these articles. Themes were developed and the content of the articles in the selected journals were coded according to categories derived from earlier studies. The results were interpreted using descriptive analysis (frequencies) and social network analysis. The reporting of the results were organized into the following categories: research areas, theoretical and conceptual frameworks, variables, methods, models, strategies, data collection and analysis methods, and the participants. The study also identified the most commonly used keywords, and the most frequently cited authors and studies in distance education. The findings obtained in this study may be useful in the exploration of potential research areas and identification of neglected areas in the field of distance education

Enver Paşa ve sürgün sultan:Enver Paşa'nın ölümünden sonra Naciye Sultan için 28 yıllık bir sürgün hayatı başladı:Öldüğüne üç ay inanamadım

Taha Toros Arşivi, Dosya No: 62-Enver Paşa Aile ve Çevres