Effect of unstable crack growth on mode II interlaminar fracture toughness of a thermoplastic PEEK composite

An end notched flexure (ENF) test was used to study the effect of growth stability on mode II interlaminar fracture toughness (GIIC) of a carbon/PEEK composite. The instability of the ENF test was used to induce both stable and unstable crack growth with a static loading. Two techniques were used to evaluate mode II fracture toughness: the traditional compliance method and the infra-red thermography technique. The compliance technique has the advantage of being simple and it has already been confirmed for standard tests. Nevertheless its results may be inaccurate for unstable crack growth propagation. The infra-red thermography technique enables fracture toughness to be accurately measured for non-standard tests in which the crack growth may be unstable. Both methods are complementary and this study came to the conclusion that GIIC is sensitive to crack growth velocity. Fracture toughness showed a low value for crack growth start and unstable propagation, and a high value for stable crack growth. The transition between a ductile fracture mode (for low crack growth velocity) and a brittle fracture mode (for high crack growth velocity) explained the important variability in GIIC values

Fundamental Phenomena and Applications of Swift Heavy Ion Irradiations

Peer reviewe

The phenomenon of breaking news in television and its legal and ethical controls - A critical study

The study searches the nature of breaking news and its growing presence in newsrooms and on television screens. It has also tried to find out the relationship of breaking news with fake news. In addition, it investigates the legal and moral controls associated with the various forms of dealing with it. The study reached a number of results, the most important of which are: The breaking news on television is no longer an exception or an unexpected case, in the light of the ferocious competition and mounting live fever but has become a rule in the news work. The emergence of new values in television coverage of breaking news. The development of the phenomenon of non-compliance with media content standards and legal and ethical controls in news coverage due to news competition. The shift of news coverage on television, from breaking news to urgent (proactive) news. The increase of claims by the regulatory bodies and control authorities for the need to respect professional, legal and ethical controls in media practice, including news. In light of its results, the study recommends the following measures: Introduction of legal articles in the audio-visual media legislation related to breaking news coverage controls. Proclamation of a media honor code for media professionals working in the field of breaking news services. - The creation of prizes for credible dealing with breaking news on TV channels. Training of professionals to distinguish between breaking news and fake news. - Introducing breaking news in media education and educational curricula. Introducing breaking news as a subject or as a primary focus in news courses in media colleges and departments

Comparative study of direct and inverse problems of cracked beams

In recent decades, the analysis and evaluation of the cracked structures were hot spots in several engineering fields and has been the subject of great interest with important and comprehensive surveys covering various methodologies and applications, in order to obtain reliable and effective methods to maintain the safety and performance of structures on a proactive basis. The presence of a crack, not only causes a local variation in the structural parameters (e.g., the stiffness of a beam) at its location, but it also has a global effect which affects the overall dynamic behavior of the structure (such as the natural frequencies). For this reason, the dynamic characterization of the cracked structures can be used to detect damage from non-destructive testing. The objective of this paper is to compare the accuracy and ability of two methods to correctly predict the results for both direct problem to find natural frequencies and inverse problem to find crack’s locations and depths of a cracked simply supported beam. Several cases of crack depths and crack locations are investigated. The crack is supposed to remain open. The Euler–Bernoulli beam theory is employed to model the cracked beam and the crack is represented as a rotational spring with a sectional flexibility. In the first method, the transfer matrix method is used; the cracked beam is modeled as two uniform sub-segments connected by a rotational spring located at the cracked section. In the second method which is based on the Rayleigh’s method, the mode shape of the cracked beam is constructed by adding a cubic polynomial function to that of the undamaged beam. By applying the compatibility conditions at crack’s location and the corresponding boundary conditions, the general forms of characteristic equations for this cracked system are obtained. The two methods are then utilized to determine the locations and depths by using any two natural frequencies of a cracked simply supported beam obtained from measurements as inputs. The two approaches are compared with a number of numerical examples for simply supported beams including one crack. The theoretical results show that the accuracy of the Rayleigh’s method to predict natural frequencies decreases for higher modes when crack depth increases. It is also found that for the inverse problem, the transfer matrix method show a good agreement with those obtained from previous works done in this field

Application of Data Communication to the Detection and Correction of Power System Faults

Data communication is an important part in modern industrial processes and is necessary in automation, monitoring, and protection purposes. This paper aims at designing a real time communication between two computers for interchanging the state of a three phase circuit to emulate a transmission line protection system in power substation. The circuit designed in Proteus ISIS is based on "symmetrical component theory" and the algorithm for exchanging data between two computers is built using TCP/IP protocol in LABVIEW environment. The application consists of monitoring and controlling three phase lines by sending the data collected to one of the computers and sending the commands back to trip relays if any fault is detected. The purpose is to prevent the propagation of this fault and to connect other sources to maintain the flow of power to the load

The Effects of Product, Price, and Consumer Lifestyle on Wardah Cosmetic Buying Decisions of Universitas Muhammadiyah Palembang.

The formulation of the problems in this study was to find out whether 1. was there any effect of product, price, and consumer lifestyle on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 2. was there any effect of product on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 3. was there any effect of price on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 4. was there any effect of consumer lifestyle on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang. This type of research was associative research. The variables were product, price, lifestyle and purchasing decisions. The population in this study were students of Universitas Muhammadiyah Palembang who used Wardah cosmetic whose numbers were not known with certainty. The sample was 100 respondents, with purposive sampling technique. The analysis technique used multiple linear regression, F test, t test, and the coefficient of determination. The results of the analysis showed that 1. there was a significant effect of product, price, and consumer lifestyle on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 2. there was a significant effect of product on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 3. there was a significant effect of price on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang, 4. there was a significant effect of consumer lifestyle on Wardah cosmetic buying decision of Universitas Muhammadiyah Palembang