2 edition of Low frequency dielectric investigations on hydrated pharmaceutical powders found in the catalog.
Low frequency dielectric investigations on hydrated pharmaceutical powders
David S. Pearson
Thesis (Ph.D) - De Montfort University, Leicester 1999.
|Statement||David S. Pearson.|
|Contributions||De Montfort University.|
The dielectric and electrical properties of insulating and semi-conducting dielectric materials as measured over wide ranges of frequency and temperature have been the subject of considerable interest in recent years. In terms of the measurements, a sample in the frequency range to Hz is regarded as a lumped-circuit element having a. Broadcasting remains a 24/7 operation, and will be critical to providing news and information to the human population in the coming weeks. Therefore, Dielectric will remain in business, with a manufacturing staff onsite. General business operations will continue from our home offices. We will continue to communicate with you if things change. Dielectric permittivity If a varying field V(t) is applied to a material, then the polarization and induced charge Q are related as where ϵ* is the complex dielectric constant. The frequency dependent complex dielectric permittivity is given by Where ϵ s and ϵ α are the low and high frequency dielectric constants respectively. Dielectric Properties of Polymers. Polymers have long been known as insulating materials and are often used to insulate cables and electrical devices. They are also called dielectrics. Traditionally, dielectric materials are made from inorganic materials such as porcelain, mica, and quartz.
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The materials used in this work are listed in Table ered to represent a broad spectrum of physical characteristics of powders used in pharmaceutical processing, they include actives, aspirin and paracetamol, and bulk excipients (additives used to improve the binding properties of the bulk drug during tabletting or as a carrier to aid absorption into the body).Cited by: Physical and dielectric properties of pharmaceutical powders Article in Powder Technology (1) August with Reads How we measure 'reads'.
This paper reports the use of low frequency dielectric measurements ( Hz–1 MHz) in the investigation of low hydrated ovalbumin. This paper reports the use of low frequency dielectric measurements ( Hz–1 MHz) in the investigation of low hydrated ovalbumin (Cited by: A dielectric resonator oscillator (DRO) is an electronic component that exhibits resonance of the polarization response for a narrow range of frequencies, generally in the microwave band.
It consists of a "puck" of ceramic that has a large dielectric constant and a low dissipation factor. Such resonators are often used to provide a frequency. Low-Frequency Dielectric Spectroscopy as a Tool for Studying the Compatibility between Pharmaceutical Gels and Mucous Tissue.
Journal of Pharmaceutical Sciences92 (9), DOI: /jpsCited by: •Datasheet: ECCOSTOCK® HiK Powder - Free Flowing Dielectric Powders.
Material Characteristics. ECCOSTOCK® HiK Powder is a is a series of granular, free flowing powders of adjusted dielectric properties Though these standard powders are extremely low loss, materials of moderate and high loss can be supplied on special order. Dielectric properties of powders and solvents The dielectric data for the dry powders and solvents at 20 C and 2, MHz are given in Table 1.
From the e0 and e00 measurements, the power reﬂected (P r) (Eq. 1), power transmitted (P t) (Eq. 2), tan delta (tan d) (Eq.
3) and penetration depth (d p) (Eq. 4) were calculated. These. Low frequency dielectric properties of human blood. Abdalla S(1). Author information: (1)Physics Department, Faculty of Science, King Abdulaziz University Jeddah, Jeddah, Saudi Arabia. [email protected] Nano- and microparticles in human blood affect drastically the charge transfer CT through the viable by: The principle used in the dielectric separation of mineral powders depends upon the fact that the grains will be attracted to needle-points when immersed in a liquid of lower e (dielectric constant) than the e of the mineral grain.
Conversely, the grains will be repelled from the needles when the liquid is of higher e. Numerous liquids were sug-File Size: KB. frequency and temperature dependences of these parame- ters for the Tl2S crystalline medium were described and analyzed as following: The complex dielectric constant of the material medium is generally formulated as two parts: ε = ε׳ + jε״, where ׳ is the real part of dielectric ε constant (RPDEC) and ε״ is the dielectric loss or theFile Size: KB.
Dielectric spectroscopy (which falls in a subcategory of impedance spectroscopy) measures the dielectric properties of a medium as a function of frequency.
It is based on the interaction of an external field with the electric dipole moment of the sample, often expressed by permittivity. It is also an experimental method of characterizing electrochemical systems.
Abstract. The passive electrical or “dielectric” properties of biological cells have been studied since the last century . Important advances in our knowledge that have accrued from the application of dielectric spectroscopy to biological systems include the recognition of the molecular thickness of biological membranes  and of the existence of voltage-gated ion channels as embodied Cited by: High-Frequency Dielectric Measurements Part 24 in a Series of Tutorials on Instrumentation and Measurement James Baker-Jarvis, Michael D.
Janezic, and Donald C. DeGroot K nowledge of the response of materials to electromagnetic (EM) fields in the radio frequency (RF) through terahertz (THz) frequency range is critical to numerous research.
frequency shift of the peak at 3 kHz, in water spectrum. Peaks at Hz and 11 kHz can be attributed to I E water alone. The spectra of the dielectric constant ε for distilled water and I E water are shown in Figure 3c. In the frequency range of less than Hz, the dielectric constants of I EFile Size: 1MB.
Currently, on‐going research is trying to enhance the dielectric constant of ceramic powder‐polymer, metal powder‐polymer, and nanotube‐polymer composites in the low frequency region. In this article, we present the dielectric properties of polypropylene (PP)‐graphite (Gr) composites in low and radio frequency by: Abstract.
The dielectric properties of pharmaceutical powder–(paracetamol, aspirin, lactose, maize starch, adipic acid) solvent (water) mixtures were measured at 2, MHz at a range of moisture contents (0– kg kg −1, dry basis) and temperatures (20–70 °C).The dielectric constant (ε′), loss factor (ε″) and penetration depth (d p) were found to be dependent on frequency Cited by: A dielectric material is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic field s.
If the flow of current between opposite electric charge poles is kept to a minimum while the electrostatic lines of flux are not impeded or interrupted, an electrostatic field can store energy. This property is useful in capacitor s, especially at radio frequencies.
Handbook of Low and High Dielectric Constant Materials and Their Applicatinos brings together into two volumes all low and high dielectric constant materials currently studied in academic and industrial research. It covers all aspects of inorganic and organic materials, from their synthetic chemistry, processing techniques, physic, structure-property relationship, and solid-state physics, to Price: $ ( oC to oC) and frequency range ( Hz to1 MHz).
The grain and grain boundary response as well as the relaxation processes at different frequencies and temperatures were also discussed. A low frequency dispersion in dielectric permittivity (LFDD), a typical characteristic of high-temperature.
C-ULF Powder (K20 Ultra-Low-Fire COG Dielectric) Features 1. MgTiO 3 based ultra-low-fire COG dielectric 2.
Dielectric Constant of 3. Excellent insulation resistance 4. High Q at high frequency 5. No Cd, Pb, Bi containing compounds Typical Physical Properties 1. Particle Size (D50) um Size: 1MB. Advances in Ultra Low Dielectric Constant Ordered Porous Materials by Richard Farrell, Tandra Goshal, Uros Cvelbar, Nikolay Petkov, and Michael A.
Morris parasitic capacitance (described above), which ensure that extra current is required so the parasitic capacitors. dielectric constant, tan2 c is the ratio K"/K' or the loss tangent.
Given a microwave field of fixed intensity and frequency, the dependence of a food's on its dielec properties K' andCited by: Description: High-frequency applications, such as antennae systems, require low energy absorption.
Trusted by manufacturers around the world, our low dielectric materials:•Ensure purity and manufacturability-POREX Virtek™ PTFE is pure PTFE and does not require a backing or support scrim like. Material Form: Film / Sheet, Polymer (Plastic / Elastomer). Dielectric’s dehydrator products have been in service in the broadcast, microwave and telephone industries for over 40 years.
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The behavior of water dynamics conﬁned in hydrated calcium silicate hydrate (C-S-H) gel has been investigated using broadband dielectric spectroscopy (BDS; 10−2– Hz) in the low-temperature range (– K).
Different water contents in C-S-H gel were explored (from 6 to 15 wt%) where water remains amorphous for all the studied. The measurement of complex dielectric properties of materials at radio frequency has gained increasing importance especially in the research fields, such as material science, microwave circuit design, absorber development, biological research, etc.
Dielectric measurement is important because it can provide the electrical or magneticFile Size: KB. In addition, such subjects as the manner of making extensive engineering investigations and of reducing data, the measurement of high voltages, the effects of impulse and high-frequency voltages, methods of draw- ing dielectric fields, outline of modern theory, various dielectric phenomena, etc., are considered/5(6).
Subject: dielectric strength of water All, I had a question during my lecture regarding the absence of a value for the dielectric strength of water in Table of Serway (p ). The best guess I had at the time is that it is probably difficult to remove all the impurities from the water, so that any experimentally obtained values vary greatly.
Abstract: We study the low-frequency polarization response of a surface-charged oblate spheroidal particle immersed in an electrolyte solution. Because the charged spheroid attracts counter-ions which form the electric double layer around the particle, using usual boundary conditions at the interface between the particle and electrolyte can be quite complicated and by: 3.
the dielectric dispersion is broad as if it is a constant-phase-angle, or low-frequency-dispersion type of relaxation in these samples [10, 13, 32], which is clear in the Argand plot. The dielectric response of the samples indicate a sum of polarization and the constant-phase-angle processes, cf.
the frequency dependence, dielectric properties of a material are characterized by relaxation time constants. A single-time-constant response is described by the Debye equation: where ε∞is the dielectric constant at frequencies much higher than 1/(2πτ), εs is the static, or very low frequency, dielectric constant, and τis the relaxation Cited by: frequency.
The increase in losses at low frequency could be associated with the polarization of the trapped charge carriers.
With increase in frequency, polarization decreases and becomes vanishing small at high frequencies. The expression for dielectric loss is given by the equation [18, 19], tan Ü L ñ 6 ì 6:) Ü á E 5 ; E) à ñ [ 5 ì.
High Dielectric Constant, Low Loss Additive Manufacturing Materials for RF/Microwave Applications Caprice Gray, Alexandra Roach, Sarah Rappaport, Andrew Dineen, Reed Irion IMAPS New England May 3.
The frequency spectrum most commonly used for dielectric heating is in the range of 3 MHz to 30 GHz, corresponding to a wavelength of m to 1 cm. The heating effect of high frequencies is based on the interaction of the electric and magnetic field, generated by the high frequency, with the insulating material.
The applied field resultsFile Size: KB. Inulin is readily dissolved in water in low concentrations (Cited by: 1.
Investigations of Novel High Dielectric Materials and New Mechanisms. Meng Guo. A dissertation submitted in partial fulfillment. of the requirements for the degree of.
Doctor of Philosophy (Chemistry) in The University of Michigan. Doctoral Committee: Professor Theodore G. Goodson III, Chair. Professor Peter F. Green.
Dk and Radio Frequency (Rf) - In general, as frequency increases, Dk will decrease. As described in the effect of temperature on As described in the effect of temperature on Dk, a room temperature cured epoxy with a Dk value of at 60Hz will result in a value of at 1KHz and at Size: KB.
The dielectric constants of powders and flaked materials are significantly smaller than [the established values for the same materials a solid. For example, although the dielectric constant of PVC is topowdered The constant for PVC is approximately to make it possible to find both C1 (and then dielectric constant of the material; see below) and R1 (and the loss tangent of C1) if we know R2 and C2.
Setup Description As an AC source, A HP function generator was used. With the amplitude of the output voltage (U1) of ~ V, it is capable to change frequency up to 50 MHz. The. over the frequency range 20 Hz-1 MHz and at the temperatu 30 and 45°C.
The real part of complex dielectric function increases significantly with the decrease of frequency below kHz, confirms the contribution of electrode polarization effect in the dielectric properties of .isothermally by scanning the frequency and have been replotted here.
A relatively high frequency has been chosen for the pre-sentation,inordertoeliminateconductivity effects present at lower frequencies. An Figure 1. Real part of dielectric function e0 against frequency f at 25 8C for the SBR/silica nanocomposites indicated on the plot.Chapter-VII Dielectric Study of Powders of Some Medicinal Seeds and Spices 7.
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