3.2.8 Dielectric studies
Dielectric study of solid polymer electrolytes is an important technique for understanding the various relaxation processes, which are associated with the ion motion. The frequency dependent dielectric constant at room temperature for the PEO with different wt% of KCl is shown in Figure 3.14(a). It is evident from the figure that the dielectric constants are significantly high in the low frequency region due to electrode polarization and space charge effects and it obeys the non-Debye type behaviour [53, 54].
At higher frequencies, the dielectric constants are almost independent of frequency. This is because, at higher frequencies periodic reversal of the field takes place so rapidly that the charge carriers will hardly be able to orient
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The dielectric constant found decreases monotonically in the lower frequency and it is independent at higher frequency. The high value of the dielectric constant at low frequencies can be attributed to the accumulation of charge carriers near the electrodes and at higher frequency the dipoles or polar molecules are unable to orient themselves in the direction of the applied field, hence the dielectric constant appears to decrease or is steady with increasing frequency [58]. The dielectric constants (εꞌ & εꞌꞌ) were found to increases with temperature at a fixed frequency for all electrolyte films due to the greater freedom of movement of the dipole molecular chains of polymer electrolytes at high temperatures. At lower temperatures, the dipoles are rigidly fixed or tightly bound in the dielectric material; therefore the field cannot change the condition of the dipoles. As the temperature increases, the dipoles become comparatively free and they respond to the applied electric field causes the change in the induced energy at the dipole site and consequently enhance the dipole motion
This chapter provides some insight into pulse wave analysis and its relation to arterial diseases. The shape of the arterial pulse wave is an augmentation of the forward traveling wave with the reflected wave. The amount of wave reflection is dependent on the arterial wall properties such as arterial stiffness and is expressed in terms of Augmentation Index. This approach has been studied extensively using various measuring techniques, all of which have respective advantages and disadvantages. The purpose of PWA can be seen in the section describing the medical conditions that affect the wave shape. The discussion is included to assist the reader in understanding the purpose of pulse wave analysis.
Cyclic voltammetry makes possible the elucidation of the kinetics of electrochemical reactions taking place at the electrode surface [31, 32]. In a typical voltammogram, there can be several peaks. From the sweep-rate dependence of the possible to investigate the role of adsorption, diffusion and coupled homogeneous chemical reaction mechanism. [33]
Schlesinger, Mordechay. "Electrochemistry Encyclopedia." Electroplating. Department of Physics, University of Windsor, Sept. 2002. Web. 17 Nov. 2013.
Throughout the past century, investigations of quantum and particle physics phenomena have proven to show the most significant concepts and ideas in the physical and sub-atomic world. However, the discoveries yet to be made are endless. One of the most fascinating concepts in the sub-atomic universe is the idea of spintronics. Spintronics is the quantum study of the independent angular momentum (not to be confused with the orbital angular momentum of the electron) of a particle, typically that of an electron (Introduction). An electron is a fundamental particle, with a negative charge, and is independently studied in the process of spintronic devices. The spin angular momentum of electrons is ±½ћ. Devices that use the properties
The word oscilloscope is a word that combines from Latin and Greek language. The first part “oscillare” derives from the Latin words meaning to swing backwards and forwards. The second part comes from Classical Greek “skopein” means to observe, aim at, examine, from which developed the Latin ending “scopium”, which has been used to form names for instruments that enable the eye or ear to make observation.
The major encounters that Tesla and Faraday faced included social, economic, intellectual barriers. Considering socially, Faraday was considered to be a “...high-priest of Nature, revealing the hidden forces...”(Shortland) People saw Faraday as the highest of his field, the one who was the closest to God in relation to understanding his creation. This also shows the social standard at this point in time, many going to church and understanding when someone references a religious point. Also, for social encounters, we have Tesla with his description f what the future will be like. This was not a reaction to the society that Tesla was around, but a prediction of what they were to become. Tesla, hoping to see that people would grow to become stronger
The first term that I noted during the movie was Conductive Polymers. Conductive polymers are almost always organic meaning a large class of chemical compounds whose molecules contain carbon. These polymers have extended delocalized bonds which are bonds found in a molecule that do not belong to a single atom or covalent bond. They are conjugated systems of double bonds and in a aromatic systems. The conjugated systems are atoms covalently bonded with alternating single and double bonds. When the electrons are removed or added into the valence bands the electrical conductivity increases. The conductive polymer has a low conductivity until the electron is removed from the valence band called (p-doping) or (n-doping) until it becomes more conductive. The movement of the charges is what is responsible for electrical conductivity. These polymers are plastic which are organic polymers and with mechanical properties such as flexibility and elasticity.
Finding and hiring an electrician to do or fix the electrical wiring in your home is not as simple as flipping through the phone book. Many times, homeowners rush into hiring an electrician without doing any background check. They want to get started as soon as possible, and in the process they end up wasting money on an electrician who do shoddy work or charge way too much. If you want an electrician who is good and dependable, not to mention charge a competitive price, you will need to spend some time doing your research. So how exactly do you pick the right electrician? Below are some things you can keep in mind when you are looking for a good electrician.
In 1998 a Maryland neurologist, Dr. Christopher Newman, was diagnosed with brain cancer and he could no longer work as a result of his disease. He claimed that the Motorola cell phone he had in 1992 to keep in touch with his patients gave him cancer. Then in 2000, he filed an $800 million lawsuit against several wireless providers including Motorola Inc., Verizon Communications Corp., Bell Atlantic Mobile Systems, and others. Within a month, the U.S. District Judge Catherine Blake dismissed the case due to lack of evidence. This case happened during a time where people were confused about how electromagnetic radiation affects the human body. Fast-forward to today and there is still confusion. A lot of people today feel like they are at risk from developing cancer from electronic devices like cell phones, microwaves, and laptops. That is simply not true.
The charge transfer complex was studied from the reaction of iodine with mesitylene in pentane. From the relationship between concentration of iodine over its absorbance and concentration of mesitylene, the equilibrium constant was determined to be 0.4183, and the molar absorptivity to be 1.3780*104 M-1cm-1. Besides, the energy of photon needed to get excited was 369.52 kJ/mol, and the binding energy (W) of the excited state of charge transfer complex was 145.82 kJ/mol which was much larger than expected of only 9 kJ/mol for iodine and
The higher the energy level in an energy source, the lower the wavelength of the energy produced, and the higher the frequency. Differences in wave energy characteristics are used to classify electromagnetic energy.
Since the farad is a large unit of capacitance, most capacitors have units of picofarads (pF) or nanofarads (nF). To this day only one type of capacitor has the ability to store enough energy to warrant measurements using a farad as the standard unit, and this is the super capacitor.
An oscilloscope is an electronic test instrument that is used to observe an electronic signal, typically voltage, as a function of time. In other words, it is a voltage versus time plotter. Oscilloscopes come in two basic types, analogue or digital, and support various features and functions useful for measuring and testing electronic circuits. An oscilloscope is a key piece of test equipment for any electronics designer.
The Earth’s magnetic field is a major component to exploring the earth. The north and the south poles have always been a guide for travelers. Using compasses, the direction of the north pole and the south pole has always been provided by the magnetic force of the magnetic field. What many people do not know though is the earth’s magnetic field provides way more than that. The magnetic field, also known as the magnetosphere, protects us from all kinds of harmful substances. Some of these substances include solar wind and harmful radiation from the sun. The magnetosphere also protects the atmosphere, which protects us.
The phenomenon called electromagnetic induction was first noticed and investigated by Michael Faraday, in 1831. Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor and is a very important concept. Faraday discovered that, whenever the magnetic field about an electromagnet was made to grow and collapse by closing and opening the electric circuit of which it was a part, an electric current could be detected in a separate conductor nearby. Faraday also investigated the possibility that a current could be produced by a magnetic field being placed near a coiled wire. Just placing the magnet near the wire could not produce a current. Faraday discovered that a current could be produced in this situation only if the magnet had some velocity. The magnet could be moved in either a positive or negative direction but had to be in motion to produce any current in the wire. The current in the coil is called an induced current, because the current is brought about (or “induced”) by a changing magnetic field (Cutnell and Johnson 705). The induced current is sustained by an emf. Since a source of emf is always needed to produce a current, the coil itself behaves as if it were a source of emf. The emf is known as an induced emf. Thus, a changing magnetic field induces an emf in the coil, and the emf leads to an induced current (705). He also found that moving a conductor near a stationary permanent magnet caused a current to flow in the wire as long as it was moving as in the magnet and coiled wire set-up.