Advanced Filler Network Characterization in Rubber

The present work is aimed at introducing new characterization techniques in filled rubber compounds. Rubber fillers such as carbon black are often used to enhance the physical properties of rubber compounds. With a sufficient amount of carbon black, a percolated filler network is formed, spanning the volume of the rubber compound. This phenomenon not only significantly improves the mechanical material behaviour, but also introduces a more complex mechanical response. Further enhancement is possible with the addition of reinforcing resins such as Novolaks, phenol–formaldehyde resins with a formaldehyde-to-phenol molar ratio of less than one. Based on the systematic studies performed, the two reinforcing materials are observed to exhibit synergistic behaviour resulting from their physical and chemical interaction. The reinforcing resin modifies the activity of the filler surface creating a more compact filler network. This leads to a lower filler network percolation threshold as well as increasing the reinforcing behaviour. This conclusion was derived from various thermo-mechanical measurements such as temperature stress scanning relaxation (TSSR) and dynamic mechanical analysis (DMA). The findings were also validated with advanced microscopical techniques such as atomic force microscopy (AFM) and transmission electron microscopy (TEM). A direct consequence of the filler network is a strain dependent behaviour such as the dynamic and quasi-static strain dependent softening effects known as Payne and Mullins effects, respectively. Within the conventional dynamic mechanical analysis (DMA) of rubber compounds, the mechanical response signal is often assumed to be rheologically linear (sinusoidal function) since in Fourier space, the first harmonic is more pronounced than the subsequent higher harmonics. However, valuable information contained in the higher harmonics can be utilised in order to further characterise the compound properties. One such approach is the large amplitude oscillatory shear (LAOS) technique which analyses the harmonics as a function of large strain deformation. While several studies have contributed to the understanding of this strain dependent nonlinearity, less emphasis was placed on the nonlinearity of the frequency domain. Utilising a resonance-based high frequency DMA, nonlinearities in the frequency domain were established by the observation of the superharmonic resonance, for the first time in rubber technology. Two distinct nonlinearities were observed, polymer induced nonlinearity and filler induced nonlinearity. The new method based on the superharmonic resonance has been successfully applied to characterise the filler network through the evaluation of the microdispersion of carbon black and its interaction with reinforcing resins.Die vorliegende Arbeit hat das Ziel, innovative Methoden zur Charakterisierung von gefüllten Kautschukmischungen einzuführen. Füllstoffe, wie Ruß, werden in Kautschuk eingesetzt, um seine physikalischen Eigenschaften zu verstärken. Mit einer ausreichenden Menge an Ruß wird ein perkolierendes Netzwerk erzeugt, das das Volumen der Kautschukmischung durchdringt. Diese Erscheinung verstärkt nicht nur das mechanische Materialverhalten, sondern führt zu einer komplexeren mechanischen Reaktion. Eine weitere Verstärkung ist durch den Einsatz netzwerkbildender Harze möglich, z.B. von Novolaken, Phenolharzen mit einem Formaldehyd-Phenol-Verhältnis kleiner eins. Auf der Basis von systematischen Studien wird ein synergistisches Verhalten der beiden verstärkenden Materialien infolge ihrer physikalischen und chemischen Wechselwirkung beobachtet. Das Verstärkungsharz verändert die Aktivität der Füllstoffoberfläche und erzeugt damit ein kompakteres Füllstoffnetzwerk. Dies führt zu einer reduzierten Perkolationsschwelle sowie zu einer zusätzlich höheren Verstärkung. Diese Schlussfolgerung wurde aus Messungen mit verschiedenen thermomechanischen Verfahren abgeleitet, wie der anisothermen Spannungsrelaxation (TSSR) und der dynamisch-mechanischen Analyse (DMA). Die Ergebnisse wurden auch mit anspruchsvollen mikroskopischen Techniken validiert, wie der Rasterkraftmikroskopie (AFM) und Transmissionselektronenmikroskopie (TEM). Eine direkte Folge des Füllstoffnetzwerks ist die Entstehung eines dehnungsabhängigen Verhaltens, das als dynamischer oder quasi-statischer Erweichungseffekt beobachtet und jeweils als Payne- oder Mullins-Effekt bezeichnet wird. Bei der dynamisch-mechanischen Analyse (DMA) von Kautschukmischungen wird häufig eine Linearität der Antwort in Bezug auf das angelegte Verformungssignal angenommen, da die Stärke der ersten Harmonischen viel höher ist als die der nachfolgenden Harmonischen. Es gibt jedoch wertvolle Informationen in den höheren Harmonischen, die verwendet werden könnten, um die Materialeigenschaften weiter zu charakterisieren. Ein solcher Ansatz ist die LAOS-Technik (engl. Large Amplitude Oscillatory Shear), mit der die Harmonischen als Funktion der Dehnung analysiert werden. Während einige Studien bereits zum Verständnis dieses dehnungsabhängigen Phänomens beigetragen haben, wurde weniger Wert auf die Nichtlinearität im Frequenzbereich gelegt. Unter Verwendung einer resonanzbasierten Hochfrequenz-DMA wurden erstmals in der Kautschuktechnologie Nichtlinearitäten im Frequenzraum durch Beobachtung von superharmonischen Resonanzen festgestellt. Zwei unterschiedliche Typen von Nichtlinearitäten wurden beobachtet, die polymerinduzierte und die füllstoffinduzierte Nichtlinearität. Die neue Methode auf der Basis der superharmonischen Resonanz wurde zur Charakterisierung des Füllstoffnetzwerkes durch Bewertung der Mikrodispersion von Ruß und dessen Wechselwirkung mit verstärkenden Harzen erfolgreich eingesetzt

Combined Human, Antenna Orientation in Elevation Direction and Ground Effect on RSSI in Wireless Sensor Networks

In this paper, we experimentally investigate the combined effect of human, antenna orientation in elevation direction and the ground effect on the Received Signal Strength Indicator (RSSI) parameter in the Wireless Sensor Network (WSN). In experiment, we use MICAz motes and consider different scenarios where antenna of the transmitter node is tilted in elevation direction. The motes were placed on the ground to take into account the ground effect on the RSSI. The effect of one, two and four persons on the RSSI is recorded. For one and two persons, different walking paces e.g. slow, medium and fast pace, are analysed. However, in case of four persons, random movement is carried out between the pair of motes. The experimental results show that some antenna orientation angles have drastic effect on the RSSI, even without any human activity. The fluctuation count and range of RSSI in different scenarios with same walking pace are completely different. Therefore, an efficient human activity algorithm is need that effectively takes into count the antenna elevation and other parameters to accurately detect the human activity in the WSN deployment region.Comment: 10th IEEE International Conference on Frontiers of Information Technology (FIT 12), 201

Application of Multilayer Thin Film Technology in Desalination Membrane

Membrane‐based desalination is the fastest growing technology in the area of desalination. Reverse osmosis (RO) and nanofiltration (NF) have been established in the last couple of decades; meanwhile, forward osmosis (FO) has begun to find its own place in the field of desalination. Typical commercial polyamide (PA) thin film composite (TFC) membrane has been mostly used in those membrane processes, but it has no drawback. Recently, a versatile, robust technique in preparing ultra‐thin films, so‐called layer‐by‐layer assembly (LbL), was adopted in fabrication of desalination membrane. This chapter highlights the most important literatures in the application of LbL assembly for preparing RO, NF and FO membranes, the obstacles and future works, which are essential for those who wish to work in the field

THE ASSOCIATION OF CREATIVITY WITH DIVERGENT AND CONVERGENT THINKING

The inspirational aspect of creativity remains shrouded in mystery. Methodological problems have hindered research into creativity, and such a situation makes the interpretation and comparison of studies problematic. The link between creativity and psychopathology is overstated by the print, electronic, and celluloid media. This paper attempts to explain the creative process from a psychological and psychiatric perspective leaving room for different unexplained aspects of generativity for open discussion. A selective survey of the literature was performed to identify scholarly views of creativity and psychopathology. Data sources included PubMed, Google Scholar, and Scopus. The concept of inspiration was examined from psychological, psychopathological, and biological standpoints. A better understanding of creativity has clinical implications. Psychopathology can facilitate creativity, but it is not the maker of creativity that involves a harmonious blending of divergent and convergent thinking. The present trend in psychiatry of medicalizing all unusual behavior is not at all productive in fostering creativity among children. The cognitively gifted children differ widely from children with autistic spectrum disorders; the creative thinking of gifted children is polythetic, whereas such potentials of autistic individuals are generally monothetic. The study of creativity helps develop an expanded model of the mind. However, research into creativity has produced contradictory results. The assumed link between creativity and mental disorder could be clarified only when we elucidate the creative process. Further research is needed in regard to the psycho-biological nature of creativity, including genetic links, implications for neuropharmacology, and the treatment of pathology or psychological disorders

Carbon Dioxide Conversion to Methanol: Opportunities and Fundamental Challenges

Greenhouse gases mitigation is one of most important challenges facing societies nowadays. Therefore, the way to reduce greenhouse gas emissions should be using carbon free sources that do not generate extra CO2 to the atmosphere. However, there is a great potential in energy carriers and other materials from CO2, with many challenges to overcome. It has been suggested that the reduction of CO2 and conversion to renewable fuels and valuable chemicals may be considered as a promising solution to reduce the greenhouse gas emissions. This chapter discusses the recent developments and remaining challenges of CO2 utilization for the efficient production of methanol. This includes novel technologies, approaches, and current barriers for the conversion of CO2 to methanol through heterogeneous catalysis, homogenous catalysis, electrochemical, photochemical, and photoelectrochemical conversion, which will contribute to the economic growth and mitigate the hazardous emissions for cleaner environment. A review of various state-of-the-art technologies for CO2 conversion to methanol was carried out aiming to establish the advances in this area and present an overview of the recent research trend for future development of new ideas for CO2 reduction into methanol in a large scale

Personality and Employees’ Information Security Behavior Among Generational Cohorts

The Big Five Factors Model (FFM) of personality traits theory was tested for its ability to explain employee information security behavior (EISB), when age, measured by generational cohort (GCOHORT), moderated the relationship between the independent variables (IVs) extraversion, agreeableness, conscientiousness, emotional stability, intellect (EACESI) and the dependent variable (DV), employees’ information security behavior (EISB) which is measured by file protection behavior (FPB). Three age groups defined GCOHORT: 52–70 years old (1946–1964, Baby Boomers), 36–51 yrs. old (1965–1980, Generation X), and 18– 35 yrs. Old (1981–1998, Millennial). Results of hierarchical multiple regressions analyses revealed statistically significant relationships between overall personality traits, four individual factors of personality traits, and the DV (p < .05). However, contrary to expectations, GCOHORT did not moderate the relationship between any of the main IVs and the DV (p > .05). Recommendations for future research are offered

Single laser light source multi-channel PSK optical communication

Two light waves which have same wavelength and same plane of polarization can interact with each other and produce interference pattern only if the path difference between two waves is less than coherent length. It also means that if path difference is more than coherent length then waves will not create interference pattern or decoding of signal will not be possible. Using this property, it was demonstrated that more than one channel can be transmitted as long as the difference in their path lengths is more than the coherence length of the light source used. © 2006 Asian Network for Scientific Informatio

Endemic dengue fever: a seldom recognized hazard for Pakistani children.

Background: Dengue fever (DF) has gained prominence as an epidemic disease in Pakistan in the recent years. However, little data exists to show its likely endemic nature. Methodology: We retrospectively analyzed blood for dengue IgM on samples obtained during a community-based surveillance for febrile illnesses in two slum areas of Karachi, Pakistan, between June 1999 and December 2001. In this period, no epidemic of DF occurred in the city. Participants were children older than 16 years who had fever \u3eor=38 degrees C for more than 72 hours and in whom other common infections were excluded, based on clinical examination and laboratory tests (blood culture, urinalysis, complete blood count, Typhidot test and peripheral blood film for malaria). Results: One hundred and fourteen blood samples were analyzed for dengue IgM ELISA, out of which 54 (47.4%) tested positive. The incidence of DF in this community was possibly as high as 185 (95% CI: 145 - 242) per hundred thousand population/year. Older children (10 - 15 years) appeared 5.5 times more likely to be affected than their younger (0 - 5 years) counterparts. Conclusions: DF is probably endemic in children in slums of Karachi, and likely to have high incidence rate. Older children are more susceptible to the disease. Further prospectively designed research is needed to confirm these findings. Until that time, DF may be included in the differential diagnosis of fever without focus in children in Karachi slums even in non-epidemic periods

Economic Analysis of Liquid drop-out Minimization in Natural Gas Pipelines

The main goal of this research work is to provide an economic evaluation about the controlling of natural gas liquid dropout. The devloped idea is to minimize the natural gas losses in pipeline integrity management companies for the sake of controlling Un-accounted for gas (UAFG). The main idea is to possibly recover those valuable liquids to convert them in a liquid fuel. The econoimc analysis of the overall problem has been discussed.  The overall associated cost with the adsorber unit is calculated. Finally the Net present value, Pay back period, Accounting rate of return and Internal rate of return has been calculated.    Key words: Economic Analysis, Hydrocarbon Natural Gas Liquids (HNGL’s), Natural Gas Pipeline