Effects of impurities on particle sizing by acoustic attenuation spectroscopy

It is important to have correct information regarding particle size in order to interpret, control, and optimize many industrial processes. Prior to the recent advent of acoustic attenuation spectroscopy, it was difficult to study particle size distribution online and under real process conditions in processes involving concentrated dispersions (suspensions or emulsions). The technique still needs improvement because it is less known how and under which conditions to employ the technique when dispersions involve impurities that could be soluble, insoluble, in the form of additives, and so on. This lack of understanding has almost halted the advancement in applications of the technique to various processes that essentially involve dispersions with impurities. This study investigates aqueous suspensions of CaCO3 at different concentrations (i.e., 5%, 10% and 20% mass/mass) with added impurities of MgCO3 (insoluble impurity), NaNO3 (soluble impurity) and sodium polyacrylate (soluble additive) at varying proportions (5%, 10%, 20% and 30% of the weight of CaCO3). The study characterizes and compares dispersion with and without impurity in order to demonstrate the possible ways in which addition of an impurity change the original acoustic attenuation spectrum of a dispersion. The study brings the conditions in which acoustic attenuation spectroscopy is capable of explaining that addition of an impurity will not change original particle size of the disperse medium

Impact of Devaluation on Trade Balance in Pakistan

The purpose of this paper is to find the impact of devaluation on trade balance in Pakistan in both long and short run using bound testing approach to Cointegration and Error Correction Mechanism (ECM). The result shows that devaluation is effective in improving trade balance and there is a cointegrated relationship between the real effective exchange rate and trade balance in the long run.

A novel seed based random interleaving for OFDM system and its phy layer security implications

In this work, a novel near optimal seed based random interlcaver is designed. An optimal interleaver scatters a given burst of errors uniformly over a fixed block of data -a property that is measured by so called 'spread'

Fabrication and characterization of curcumin loaded ZnO nanoparticles and their in vitro antibacterial activity

Nanotechnology is broadly defined as the study and development of the chemical physical and natural properties of materials, devices, and structures that differ from those found on a larger scale, and Nano patents are derived from the Japanese language. Zinc oxide nanoparticles are used in a wide-ranging applications, visible light, catalytic actions, ultrasonic, deodorizing, diabetes treatment, cosmetics, lasers, paints, ultraviolet light absorbing constituents, rubber industry, catalytic agent for light flattening, and specifically in the medical and pharmaceutical sciences7. Curcumin is a useful plant-based material derived from "turmeric" that has the potential to be used in the green synthesis of ZnONPs. This is due to the influence of "polyphenol," which may also result in the formation of ZnONPs during the reduction process. Characterization reported Spherical particles with varying size from few nanometers to about 900 nm. The antibacterial activity by disk diffusion method against E. coli (Gram negative), Pseudomonas aerugionsa, Bordetella bronchiseptics & Micrococcus luteus revealed mark able zone of inhibition that declared potent antibacterial activity of Curcumin ZnO NP against gram positive bacteria more than negative ones where Ciprofloxacin was used as standard

Effects of concentration of dispersions on particle sizing during production of fine particles in wet grinding process

Stirred media milling is a prospective technology for producing colloidal dispersions by means of wet grinding process. In the past, many researchers have studied the effects of different operating parameters such as size, shape, nature and quantity of grinding medium, the speed of agitator in grinding chamber, the feed rate of dispersions, etc. in stirred media mills. However, it is still less known how particle sizing which generates valuable information of particle size of the product to interpret, control and optimize the grinding process, is influenced by the concentration of the dispersion during stirred media milling where particles change their size from micron to colloidal range rapidly. One of the reasons of this lack had been our incapability in the past to study the particle size distribution of dispersions without dilution. The recent advent of acoustic attenuation spectroscopy is known to be capable of studying dispersions without dilution, under real process conditions and on line. The study employs acoustic attenuation spectroscopy to investigate the effects of concentration of dispersions of CaCO3 on its particle sizing during size reduction process in a stirred media mill (LabStar manufactured by NETZSCH). The dispersions of CaCO3 at 5%, 10%, 20% and 30% (m/m) were studied about six hours under a selected set of operating conditions. Contrary to the existing knowledge obtained through other techniques of particle sizing that are based on the principle of dilution, acoustic attenuation spectroscopy shows that, under certain grinding time at given operating conditions, increase in concentration of dispersion results in better grinding results yielding smaller particles. The causes behind the differences in results of acoustic attenuation spectroscopy and dynamic light scattering have been thoroughly investigated. We find certain limitations of acoustic attenuation spectroscopy in particle sizing. A typical phenomenon which causes misleading trends in particle sizing is multiple scattering in acoustic measurements. Multiple scattering, particularly, influences acoustic results when particles approach to fine size range during size reduction process

Role of RNA Interference (RNAi) in the Moss Physcomitrella patens

RNA interference (RNAi) is a mechanism that regulates genes by either transcriptional (TGS) or posttranscriptional gene silencing (PTGS), required for genome maintenance and proper development of an organism. Small non-coding RNAs are the key players in RNAi and have been intensively studied in eukaryotes. In plants, several classes of small RNAs with specific sizes and dedicated functions have evolved. The major classes of small RNAs include microRNAs (miRNAs) and small interfering RNAs (siRNAs), which differ in their biogenesis. miRNAs are synthesized from a short hairpin structure while siRNAs are derived from long double-stranded RNAs (dsRNA). Both miRNA and siRNAs control the expression of cognate target RNAs by binding to reverse complementary sequences mediating cleavage or translational inhibition of the target RNA. They also act on the DNA and cause epigenetic changes such as DNA methylation and histone modifications. In the last years, the analysis of plant RNAi pathways was extended to the bryophyte Physcomitrella patens, a non-flowering, non-vascular ancient land plant that diverged from the lineage of seed plants approximately 450 million years ago. Based on a number of characteristic features and its phylogenetic key position in land plant evolution P. patens emerged as a plant model species to address basic as well as applied topics in plant biology. Here we summarize the current knowledge on the role of RNAi in P. patens that shows functional overlap with RNAi pathways from seed plants, and also unique features specific to this species

Impact of Brand Awareness and Loyalty on Brand Equity

The objective of our research is to know the factors that impact on brand equity. The study considered the brand awareness and loyalty of brand, to search out that how these influence the brand equity. The study was based on the primary which gathered from 200 respondents by means of a questionnaire. The application of random sampling technique are used and statistical tool like SPSS software was used for checking the reliability of questionnaire and for revealing the result of this research the correlation analysis are used. The research result indicates that the brand awareness and loyalty influence the brand equity. Main focus of every business is the customer attraction, the findings and recommendation of this research will help the managers to develop insight of research factors about the brand equity. Keywords: brand awareness, brand loyalty, brand equit

A Bayesian Approach For Image-Based Underwater Target Tracking And Navigation [TC1800. A832 2007 f rb].

Operasi pemeriksaan dan pemantauan di dasar laut merupakan aktiviti penting untuk industri di luar persisiran pantai terutamanya bagi tujuan pembangunan dan pemasangan infrastruktur. Sejak kebelakangan ini, pemasangan struktur di dasar laut seperti saluran paip gas atau petroleum dan kabel telekomunikasi telah meningkat. Pemeriksaan rutin adalah sangat mustahak untuk mencegah kerosakan. Undersea inspections and surveys are important requirements for offshore industry and mining organisation for various infra-structures installations. During the last decade, the use of underwater structure installations, such as oil or gas pipeline and telecommunication cables has increased many folds