Cyber victim and bullying scale: A study of validity and reliability

The purpose of this study is to develop a reliable and valid scale, which determines cyber victimization and bullying behaviors of high school students. Research group consisted of 404 students (250 male, 154 male) in Sakarya, in 2009–2010 academic years. In the study sample, mean age is 16.68. Content validity and face validity of the scale was provided via field specialists’ judgment. Confirmatory and exploratory factor analyses were performed for investigation of the factor structure of the scale. As a result of principal component analysis of cyber victim subscale three factors emerged which accounted for the 46.38% of the total variance. Also for cyber bullying subscale, same three factors emerged accounting for the 49.18% of the total variance. Scales with 22 items under 3 factors were tested with confirmatory factor analysis for each victim and bullying variables. Three factors were named as cyber verbal bullying, hiding identity and cyber forgery. Three factors model of scales were found theoretically and statistically fitted after confirmatory factor analysis. For criterion related validity the correlation between cyber victim and bullying scale and Aggression Scale was calculated as .27 and .36, respectively. The internal consistency coefficients calculated for reliability. Cyber victim and bullying scales’ internal consistency coefficients were .89 and split-half coefficients were .79. for both scales. Test-retest reliability for cyber victim .85, for cyber bullying respectively .90 was found. These results demonstrate that the Cyber Victim and Bullying Scale’ is a valid and reliable instrument.     

Effect of Using Thorium Molten Salts on the Neutronic Performance of PACER

Utilization of nuclear explosives can produce a significant amount of energy which can be converted into electricity via a nuclear fusion power plant. An important fusion reactor concept using peaceful nuclear explosives is called as PACER which has an underground containment vessel to handle the nuclear explosives safely. In this reactor, Flibe has been considered as a working coolant for both tritium breeding and heat transferring. However, the rich neutron source supplied from the peaceful nuclear explosives can be used also for fissile fuel production. In this study, the effect of using thorium molten salts on the neutronic performance of the PACER was investigated. The computations were performed for various coolants bearing thorium and/or uranium-233 with respect to the molten salt zone thickness in the blanket. Results pointed out that an increase in the fissile content of the salt increased the neutronic performance of the reactor remarkably. In addition, higher energy production was obtained with thorium molten salts compared to the pure mode of the reactor. Moreover, a large quantity of ²³³U was produced in the blanket in all cases.     

Novel methodologies and a comparative study for manufacturing systems performance evaluations

The purpose of this work is to establish complex fuzzy methodologies in the evaluation of a manufacturing system’s performance. Many empirical studies have been presented about the evaluation of manufacturing system’s performance. However, the performance evaluation is quite subjective, since it relies on the individual judgment of the managers who have different, various and multi-factor assessment methods of a system’s performance. In this study, two fuzzy modeling designs were developed and in the construction of the models, a hierarchy process was used. In the first method, the performance factors and the Analytic Hierarchy Process (AHP) were fuzzified and the use of fuzzy numbers and a fuzzy AHP for this problem was recommended. Also, the relative importance of these factors with respect to each other and their contribution to the overall performance was quantified with fuzzy linguistic terms. In the other method, we proposed Approximate Reasoning (AR) based on experts’ knowledge which is represented with the collection of the rules. These fuzzy rule bases are “if-then” linguistic rules that are formed with linguistic variables such as poor, below average, average, above average and superior. Additionally, the problem was structured with the normal AHP and System-With-Feedback (SWF), Finally, these methods were compared. The results showed that fuzzy AHP leads to the best result. It is expected that the recommended models would have an advantage in the competitive manufacturing including cost, flexibility, quality, speed and dependability.     

The Effect of B Addition on the Microstructural and Mechanical Properties of FeNiCoCrCu High Entropy Alloys

High-entropy alloys (HEAs) are a new class of alloys having equiatomic ratios of alloying elements in their composition. Boron is an important element that can increase the strength of steels and wear resistance of hard facing coatings with its high hardness compounds. The effect of boron (B) in FeNiCoCrCu-based HEAs has not been studied in detail to date. In the current study, the microstructural and mechanical properties of FeNiCoCrCuB_x HEAs with varying boron contents (x = 1, 2, 3, 4, 5 at. pct) were investigated using specimens prepared by two-stage processing (sintering and vacuum arc melting). Microstructural and structural studies were carried out using optical microscopy, scanning electron microscopy, electron probe microanalysis, X-ray diffraction, and differential scanning calorimetry. Vickers microhardness and three-point bending tests were also performed to observe the variations in mechanical properties. Results showed that the microstructures of HEAs are generally dendritic and contain two different FCC phases, i.e., Fe-Ni-Co-Cr-rich dendritic and Cu-rich interdendritic phases. The hardness values increased with increasing B content with a maximum hardness of 337 HV. According to three-point bending test results, the highest strength of about 1900 MPa and good ductility were obtained with HEA-3 (3 at. pct B).

     

The impact of stochastic resource availability on cognitive network performance: modeling and analysis

Cognitive radio networks emerge as a promising solution for overcoming shortage and inefficient use of bandwidth resources by allowing secondary users (SUs) to access the primary users' (PUs) channel so long as they do not interfere with them. The dynamical spectrum availability makes SU's packet average delay one of the most important performance measures of a cognitive network. It is important to understand the nature of delay, as well as its dependence on PU behaviors. In this paper, we analytically model and analyze the dynamics of the spectrum availability and their impact on the SU's packet delay. The cognitive network is modeled as a discrete‐time queueing system. PU channel occupancy is modeled as a two‐state Markov chain. Our contribution in this paper is defining and characterizing the properties of the random process that describes the availability of the opportunistic resources. In addition, we apply the mean residual service time concept to achieve an analytical solution for the queueing delay. Moreover, inspired by the slotted Aloha system, we model the packet service mechanism and determine the manner in which it depends on the resource availability. The delay becomes unbounded if the spectrum availability dynamics are not carefully considered in network design. Copyright © 2015 John Wiley & Sons, Ltd.     

Role of public space design on the perception of historical environment: A pilot study in Amasya

The experience, perception, awareness, and appreciation of the environment created by public spaces are important elements of urban design. In this context, a strong link exists between perception, public spaces, and historical cities. Amasya is one of the multilayered historical cities in Anatolia. Amasya’s holistic urban texture, close relationship with the river, and public spaces are associated with both the Iris River and the historical texture. This pilot study examines the Yalıboyu Promenade, a contemporary open public space designed along the river and across the historical texture in Amasya in Turkey to reveal how it affects people’s perception of the historical environment. The study uses the mixed method approach, which includes qualitative and quantitative data. Following the theoretical discussion, the study investigates the context of the promenade. The survey results revealed how the first-time visitors had perceived the historical texture of the promenade based on Rapoport’s method of using environmental signs. The results were interpreted by jointly evaluating qualitative and survey data. Furthermore, although some aspects need improvement, the promenade solidifies the perception of the historical environment. Overall, when the public space is integrated with the historical environment and public life, it offers multidimensional contributions that cannot be ignored. Therefore, examining the promenade from perceptual aspects and offering a design approach to promote integration with the historical environment may help to establish a precedent case for future initiatives.     

Cause of Damage and Failures in Silo Structures

Silos are special structures subjected to many different unconventional loading conditions, which result in unusual failure modes. Failure of a silo can be devastating as it can result in loss of the container, contamination of the material it contains, loss of material, cleanup, replacement costs, environmental damage, and possible injury or loss of life. Silo damage and failures that occurred in different regions of the world are presented in the paper using illustrative photos. Also provided are a review and discussion of the common or spectacular silo failures due to explosion and bursting, asymmetrical loads created during filling or discharging, large and nonuniform soil pressure, corrosion of metal silos, deterioration of concrete silos due to silage acids, internal structural collapse, and thermal ratcheting. Silo damage and failures from several earthquakes are also presented.     

EFFECT OF ELECTRONIC IRRADIATION IN THE PRODUCTION OF NbSe2 NANOTUBES

In this work, we report the production of NbSe₂ (niobium diselenide) nanotubes formed by irradiating NbSe₂ with high doses of electron irradiation. The apparatus used for the irradiation was a 2 MeV Van de Graaff accelerator at the following conditions: voltage 1.3 MeV, current 5 μA, dose rate 25 kGy/min, and total dosage 1000 kGy. These conditions were maintained fixed while irradiation dosage was changed between 100, 250 and 500 Mrad. We observed enormous and very well defined nanotubes with a length of several nm and width of a few nm, which are hollow and capped at one end. As the level of irradiation is increased to 500 Mrad, onion-like structures were observed.     

WSe2 Nanotubes: Their Formation by Electron Irradiation

The discovery of multi-walled carbon nanotubes¹ and single-walled carbon nanotubes² has prompted numerous studies of the structure, properties^3,4, and potential applications^5,6of these materials. For example, nanotubes are expected to have a high strength-to-weight ratio⁶, which is advantageous in advanced composites to be used in high performance materials such as aircraft frames. The small dimensions of the tubes show promise for use as a gas absorption medium⁷, a field emitter for use in flat-panel displays⁸, and nanoscale electronic devices⁹.