Adaptive Synchronization of Robotic Sensor Networks

The main focus of recent time synchronization research is developing power-efficient synchronization methods that meet pre-defined accuracy requirements. However, an aspect that has been often overlooked is the high dynamics of the network topology due to the mobility of the nodes. Employing existing flooding-based and peer-to-peer synchronization methods, are networked robots still be able to adapt themselves and self-adjust their logical clocks under mobile network dynamics? In this paper, we present the application and the evaluation of the existing synchronization methods on robotic sensor networks. We show through simulations that Adaptive Value Tracking synchronization is robust and efficient under mobility. Hence, deducing the time synchronization problem in robotic sensor networks into a dynamic value searching problem is preferable to existing synchronization methods in the literature.Comment: First International Workshop on Robotic Sensor Networks part of Cyber-Physical Systems Week, Berlin, Germany, 14 April 201

Effect of annealing ambient conditions on crack formation mechanisms of bulk Bi-2212 ceramic systems

This study paves way to examine the influence of different annealing conditions (temperature range of 830-850°C and duration intervals 24-48 h) on the fundamental mechanical performance and characteristic quantities of polycrystalline Bi2.1Sr2.0Ca1.1Cu2.0Oy (Bi-2212) superconducting ceramics by means of Vickers microindentation hardness tests at the various indentation test loads (0.245 N≤F≤2.940 N) and some available theoretical approaches. The annealing ambient plays an important role on the operable slip systems and crystal quality. The bulk Bi-2212 superconducting compound prepared at 840 °C and 24 h is found to be the least sensitive to the applied test load due to less structural problems, voids, cracks and stress raisers in the crystal system. Conversely, the excess annealing ambient complicates remarkably the control of crack growth size and velocity. Thus, relatively lower load can lead to the formation of crack and acceleration of crack rate up to the critical size and terminal velocity. The samples exhibit the typical indentation size effect (ISE) behavior as a result of predominant character of elastic recovery mechanism. As for the theoretical examination in the saturation limit regions, the indentation-induced cracking (IIC) model wins the comparison as it provides the most accurate results to the experimental findings

A novel research on the subject of the load-independent microhardness performances of Sr/Ti partial displacement in Bi-2212 ceramics

This work is interested in the critical changes in the load-independent microhardness performance parameters with the partial substitution of Sr2+ inclusions for the Ti4+ impurities in the Bi-2212 inorganic solids with the help of the theoretical approximations as regards Meyer's law (ML), proportional sample resistance (PSR), modified proportional sample resistance (MPSR), elastic/plastic deformation (EPD), Hays-Kendall (HK) and indentation-induced cracking (IIC) models found on the experimental microhardness tests applied to a variety of test loads between 0.245 and 2.940 N for the first time. Moreover, Ti-substituted Bi-2212 bulk ceramics (Bi2.1Sr2.0-xTixCa1.1Cu2.0Oy) are prepared within mole-to-mole ratios of x = 0.000, 0.010, 0.030, 0.050, 0.070, 0.100 by the standard solid-state reaction method in the atmospheric pressure conditions. It is provided that Ti partial substitution in the superconducting system descends unsmilingly the mechanical durability, stability, strength, toughness, critical stress, stiffness and flexural strengths of Bi-2212 superconducting solids studied owing to the increment of crystal structural problems. Moreover, it is obtained that the degradation in the crystal structural leads to diminish the typical ISE characteristic of Bi-2212 superconducting ceramic compounds. At the same time, the results show that all the models (especially IIC approach) can serve as the suitable descriptors for the determination of the variation in the load-independent mechanical performances of the Bi-2212 superconducting materials

Bi-2223 Süperiletken Seramiklerde Peletizasyon Basıncının Yapısal, Elektriksel ve Mekanik Özellikler Üzerine Etkisi

Bu çalışmada Bi-2223 tozlar farklı peletizasyon basınç değerleri ile külçe formuna getirilmiş ardından külçeler 840ºC’de 36 saat tavlanmıştır. Basıncın Bi-2223 külçelerin yapısal, mekanik ve elektriksel özellikleri üzerine etkileri incelenmiştir. Yapısal analizlerin değerlendirilmesi için X-ışını Kırınımı (XRD) spektroskopisi ölçümleri kullanılmıştır. Mekanik analizler için oda sıcaklığında Vickers Mikrosertlik ölçümleri yapılmıştır. Elektriksel analizlerde ise dört kontak I-V ölçümleri kullanılmıştır. Elde edilen sonuçlara göre, Bi-2223 kristal faz yoğunluğunun, sertlik değerinin ve elektrik taşıma kapasitesinin basınca ciddi bir şekilde bağlı olduğu görülmüştür. Bu bağlamda, basıncın artması ile sertlik değerlerinin kristal yapıdaki faz geçişlerine ve yüzey artık basınç gerilim bölgelerinin artışına bağlı olarak yükseldiği tespit edilmiştir. Ayrıca, hesaplanan elastisite modülü ve akma dayanımı gibi genel mekanik performans değerlerinin basınca bağlı olarak arttığı gözlemlenmiştir. Bu bulgu kristal yapıda hali hazırda var olan kovalent ve özellikle iyonik bağ kuvvetlerinin artmasının sonucu olabilir. Bununla birlikte, numunelerin plato limit bölgelerinde yükten bağımsız mikrosertlik değerleri Meyer yasası, Orantılı Numune Direnç (OND) ve Indentation Induced Cracking (IIC) yöntemleri ile analiz edilmiştir. Analiz sonucunda IIC modelin gerçek mikrosertlik değerlerini incelemede daha başarılı olduğu bulunmuştur. Kritik akımın uygulanan basıncın artması ile düştüğü gözlemlenmiştir. Örneklerin yoğunlukları Arşimet yasası kullanılarak ölçülmüştür. Teknolojik kullanım alanına bağlı olarak külçe Bi-2223 örneklerin üretiminde uygulanması gereken optimum basınç değeri detaylarıyla tartışılmıştır

Degradation in fundamental characteristic features of Bi-2212 superconducting ceramic material with Sr/Ti partial substitution

The present work investigates the vital differentiations in some basic characteristic properties including the crystallinity quality, flux pinning mechanism, superconducting, dc electrical features, grain boundary coupling problems and strength of connection between the superconducting grains in the poly-crystallized Bi2.1Sr2.0-xTixCa1.1Cu2.0Oy cuprate ceramic materials with the partial aliovalent substitution of Sr2+ impurities for the Ti4+ foreign additives in the crystal system. All the materials are prepared by the standard solid-state reaction method, and the characterization of samples produced is thoroughly performed by the typical experimental measurements such as dc electrical resistivity over the temperature, critical current density and powder X-ray diffraction investigations. It is obvious that all characteristic properties tend to diminish constantly with the augmentation of the aliovalent Sr/Ti partial replacement level, and in case of x=0.10 they reach the global minimum values. To illustrate, the low Bi-2212 superconducting phase diverges from the stabilization because of new induced permanent crystal structure (crystallinity) problems such as the voids, porosity, defects, texturing, cracks, grain boundary coupling problems, grain alignment distributions, stress raisers, omnipresent flaws and crack initiation sites in the crystal system. Besides, the presence of Ti impurities leads to the formation of new impurity phases related to very low superconducting and characteristic TiO2 phase, being favored by either the decrement of c lattice cell parameter or increment of a-axis length. The similar findings are observed in the temperature dependent electrical resistivity measurements. Namely, the electrical resistivities at the normal state are found to increase dramatically from about 74.75-180.47 mcm whereas the offset and onset critical temperature values are recorded to diminish from 82.11K (for the pure sample) to 50.52K (for the sample prepared with x=0.10 substitution level) and 84.03-75.14K, respectively, with the enhancement in the substitution level. Likewise, the Sr/Ti partial replacement affects negatively not only the thermal fluxon motions of correlated two-dimensional pancake vortices but also the ability and strength of vortex lattice period, elasticity, effective and active energy barriers for the flux pinning centers in the Bi-2212 superconducting crystal lattice. In this respect, the Sr/Ti partial substitution mechanism is ploughed to improve the fundamental characteristic features

The association of self-discrepancy with depression and anxiety: Moderator roles of emotion regulation and resilience

Self-discrepancy theory posits that people experience emotional vulnerabilities to specific emotions when they have discrepancies between their actual, ideal and ought selves. The purpose of the current study was to test the effect of self-discrepancies (discrepancies between actual self and ideal, ought, and undesired selves) on depression and anxiety in a Turkish population, and to examine the moderator roles of emotion regulation and resilience in the relationship between self-discrepancies and negative emotions. Data were obtained from 729 participants. Results showed that ideal self-discrepancy is related to depression, but not anxiety. However, contrary to self-discrepancy theory (SDT), it was found that ought self-discrepancy is related to depression, but not anxiety. Additionally, undesired self-discrepancy is related to both depression and anxiety. According to moderation analyses resilience - but not emotion regulation - moderates both the relationships between ideal self-discrepancy and depression and undesired self-discrepancy and depression. Finally, both resilience and emotion regulation moderate the relationship between ought self-discrepancy and anxiety. This study presents an examination of SDT in a Turkish population, which is a relatively understudied non-Western culture. Furthermore, it presents the influence of emotion regulation and resilience on self-discrepancies, which enhances the understanding of SDT

Mechanical properties and repair bond strength of polymer-based CAD/CAM restorative materials

Information on the mechanical properties and repairability of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks is scarce. Five CAD/CAM blocks with similar indications were evaluated, including four resin nanoceramics, one polymer-infiltrated ceramic network (PICN), and one feldspathic ceramic. CAD/CAM blocks were sectioned into 4 mm x 1.2 mm x 13 mm bars for flexural strength (FS), and 4 mm thick blocks were prepared for elastic modulus (EM), nanohardness (NH), and microshear bond strength (mu SBS) testing. FS of the CAD/CAM blocks was determined using a three-point bending test, whereas EM and NH values were measured using a nanoindenter. The reparability of the tested block materials was determined by the mu SBS test. One-way ANOVA was conducted for FS, EM, NH, and mu SBS followed by Tukey's pairwise comparison (alpha < 0.05). FS ranged from 115 to 207 MPa, EM from 8.21 to 44 GPa, NH from 0.76 to 7.24, and mu SBS from 24.9 to 30.6 MPa. The findings of the present study revealed that resin nanoceramic blocks exhibited higher FS values than PICN and feldspathic ceramic, and they have acceptable mechanical properties for the fabrication of single-unit restorations according to the ISO 6872:2008. Furthermore, all CAD/CAM blocks tested can be successfully repaired regarding their recommended repair protocol

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials

PURPOSE. The aim of this study was to evaluate the microshear bond strength (mu SBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS. Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, mu SBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS. The findings revealed that silane application yielded higher mu SBS values (P<.05). All surface treatments were showed a significant increase in mu SBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION. Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases

Utility of diffusion-weighted MRI to detect changes in liver diffusion in benign and malignant distal bile duct obstruction: The influence of choice of b-values

WOS: 000388250400013PubMed ID: 27592163Purpose: The study sought to evaluate the potential of diffusion-weighted magnetic resonance imaging to detect changes in liver diffusion in benign and malignant distal bile duct obstruction and to investigate the effect of the choice of b-values on apparent diffusion coefficient (ADC). Methods: Diffusion-weighted imaging was acquired with b-values of 200, 600, 800, and 1000 s/mm(2). ADC values were obtained in 4 segments of the liver. The mean ADC values of 16 patients with malignant distal bile duct obstruction, 14 patients with benign distal bile duct obstruction, and a control group of 16 healthy patients were compared. Results: Mean ADC values for 4 liver segments were lower in the malignant obstruction group than in the benign obstruction and control groups using b = 200 s/mm(2) (P .05). There were no correlations between the ADC values of liver segments and liver function tests. Conclusion: Measurement of ADC shows good potential for detecting changes in liver diffusion in patients with distal bile duct obstruction. Calculated ADC values were affected by the choice of b-values

Duygu düzenleme becerilerinin psikolojik sağlık üzerindeki etkisinin Amerika ve Türkiye örnekleminde incelenmesi

Işık Savaşır Klinik Psikoloji Sempozyumu (9. : 2019 : Gazimağusa, KKTC)Duygu düzenleme becerilerinin ruhsal sağlık üzerindeki etkileri birçok çalışma ile desteklenmiştir. Duygu düzenleme stratejilerinin kültürden de etkilendiği düşünülmektedir. Bu çalışmanın amacı kişisel ve kişilerarası duygu düzenleme becerilerinin psikolojik iyi olma haline ve psikolojik belirtilere etkilerini Amerika ve Türkiye örnekleminde incelemektir. Çalışmaya Amerika’dan 125 (99’u kadın, 26’sı erkek), Türkiye’den 120 (68’i kadın, 52’si erkek) kişi katılmıştır. Genel Bilgi Formu, Duygu Kabul Ölçeği, Duygu Düzenleme Ölçeği, Bilişsel Davranışsal Kaçınma Ölçeği, Kişilerarası Duygu Düzenleme Ölçeği, Yaşam Doyum Ölçeği, Öznel Mutluluk Ölçeği ve Depresyon, Kaygı, Stres Ölçeği uygulanmıştır. Türkiye örnekleminde bilişsel yeniden değerlendirme, baskılama, bilişsel davranışsal kaçınma, perspektif alma, yatıştırılma ve sosyal model alma psikolojik iyi olma ile;duyguları kabul edememe, baskılama, bilişsel davranışsal kaçınma ve olumlu duyguyu arttırma psikolojik belirtiler ile ilişkili bulunmuştur. Amerika örnekleminde ise bilişsel yeniden değerlendirme ve bilişsel davranışsal kaçınma psikolojik iyi olma ile; duyguları kabul edememe, duyguyu yeniden düzenleme, bilişsel davranışsal kaçınma ve kişilerarası duygu düzenleme stratejilerinden yatıştırma psikolojik belirtiler ile ilişkili bulunmuştur. Bulgular duygulardan kaçınma, duyguları baskılama ve kabul etmemenin psikolojiye olumsuz etkilerini, bilişsel yeniden değerlendirmenin ise olumlu etkilerini göstermiştir.No sponso