Performance Analysis of CDMA System Using Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum Techniques

In digital communication system, selection of the most appropriate access method is a challenging task. To meet this challenge we have to be familiar with the technologies and system architectures on the CDMA digital cellular system. The demand for high speed mobile wireless communications is rapidly growing. DS-CDMA plays the best competitive role for achieving the high data capacity and spectral efficiency requirements for communication systems. This paper represents the performance analysis of CDMA using direct sequence and frequency hopping technique in a Fadin

Development of a Microarray Biosensor for Real-Time and Continuous Measurement of Neurochemicals

Continuous simultaneous measurement of glutamate (GLU), an excitatory neurochemical, and γ-aminobutyric acid (GABA), an inhibitory neurochemical, constitutes one of the major challenges in neuroscientific research. Maintaining appropriate levels of GLU and GABA is important for normal brain functions. Abnormal levels of GLU and GABA are responsible for various brain dysfunctions, like epilepsy and traumatic brain injury. GLU and GABA being non-electroactive are challenging to detect in real-time. To date, GABA is detected mainly via microdialysis with a high performance liquid chromatography (HPLC) system that employs electrochemical (EC) and spectroscopic methodologies. However, these systems are bulky and unsuitable for real-time continuous monitoring. As opposed to microdialysis, biosensors are easy to miniaturize and are highly suitable for in-vivo studies. Unfortunately, this method requires a rather cumbersome process that relies on externally applied pre-reactors and reagents. Here, we report the design and implementation of a GABA microarray probe that operates on a newly conceived principle. It consists of two microbiosensors, one for GLU and one for GABA detection, modified with glutamate oxidase and GABASE enzymes, respectively. The detection of GABA by this probe is based upon the in-situ generation of α-ketoglutarate from the GLU oxidation that takes place at both microbiosensor sites. By simultaneously measuring and subtracting the H2O2 oxidation currents of GLU microbiosensor from GABA microbiosensor, GABA and GLU can be detected continuously in real-time in vitro and ex vivo. This mechanism happens without the addition of any externally applied reagents. We optimized our novel approach in commercially available ceramic-based probes. The GABA probe was successfully tested in an adult rat brain slice preparation. However, those electrodes are geometrically limited (we cannot have a sentinel site at the same spatial level as GLU and GABA sites). Keeping theseissues in mind, we have developed a microwire array sensor that is not only capable of simultaneous measurement of GLU and GABA, but is also able to track signal resulting from interferents (e.g. Ascorbic Acid, AA). The unique geometry enables these microwire probes to measure GLU, GABA and interferents in the same spatial level. A Simple fabrication procedure and easy integration with the existing amperometric systems allow us to use them in cell culture, brain tissue, and in vivo recordings as an inexpensive alternative to our planar electrodes. We demonstrated the effectiveness of the probes in rat brain tissue. We were able to get. Additionally, we determined the excitation/inhibition (E/I) ratios for different stimulations which have clinical relevance. Our results about this E/I balance can help refine electrical stimulation parameter for different clinical purposes (e.g. deep brain stimulation). Finally, we successfully tested our probe in awake-free behaving rats. In summary, our results suggest that microwire probes have the potential to become a powerful tool for measuring GLU and GABA in various ex-vivo and in-vivo disease models, such as epilepsy

An Empirical Investigation of the Impact of Foreign Remittances on Poverty in Developing Countries

Remittances sent to home countries by migrant workers became significant in amount. Such funds can have profound implications for economic development, human welfare and poverty reduction in a developing country context. This paper examines the impact of foreign remittances on poverty in selected developing countries. A set of time series data has been utilized to empirically check the relationship between remittances and poverty for a list of 44 developing countries worldwide. For the purpose of the study, the ‘Three Stage Least Squares’ (TSLS) regression technique has been applied. A separate analysis for a group of countries among the list which recorded a remittances to GDP ratio of 2% or more has been performed. The study finds that remittances have a significant negative impact on poverty in a developing country

Foreign Direct Investment (FDI) and Economic Reforms: The South Asian Perspective

Foreign Direct Investment (FDI) flow in the economies of South Asia has not been satisfactory. However, these countries got an upward shift in their inward FDI flow after they had started to liberalize their economies in the 1980s. This paper examines some aspects of FDI flow in four major South Asian economies namely Bangladesh, India, Pakistan and Sri Lanka. Various trends of FDI flow to these countries are analyzed using recent data. An empirical estimation of the impact of economic liberalization reforms on inward FDI flow of these countries is conducted using a data set ranging from 1991 to 2012 by the panel fixed effect model. The empirical findings of the paper suggest that trade liberalization, capital market liberation and fiscal reforms are positively correlated with FDI flow. This study suggests that economic liberalization reforms need to be continued in these countries in order to support more and more FDI flows. Keywords: FDI, economic liberalization reform, South Asia and panel fixed effect mode

Numerical evaluation and analysis of the adhesion phenomena in thermal barrier coating systems through bio-mimicking plasma process

Thermal Barrier Coatings or TBCs when abbreviated are an imperative part of the thermal protection system of expensive equipment and machinery in the automobile and aeronautics industry. They provide protection to expensive alloy materials upto a temperature of 2700° C without expensive metallurgical additions. Unfortunately, the problem of coating adhesion has plagued the TBC field for years, leading to catastrophic failures in critical TBC systems. Efforts to chemically improve bond strength has not been entirely successful, so the only other efficient way to do this would be some kind of mechanical interlocking that occurs at micro/nano scales. This research work deals with the improvement of adhesion in TBC systems by numerical simulation and bench-marking of micro-geometric surface features that has been synthesized or reproduced in laboratory environment through electrochemical operations. For this, several geometries that benefit mechanical interlocking, and consequently improvements in mechanical \u27adhesion\u27 in TBCs has been compared. To simulate the mechanical and thermal loading on the micro geometries and to observe their effect, the commercial finite element software COMSOL was used. An analogy was drawn between the biological, Van der Waals dry adhesion mechanism in Gecko feet and that in the top surface of the thermally grown oxide (TGO) layer in TBC whereas the \u27mushroom head geometry\u27 in the Gecko feet provides improved adhesion (as much as 10 folds) compared to other geometries (spatular head, spherical head, or plain triangular crevices). An affordable synthesis process, termed “Electrolytic Plasma Processing (EPP) for recreating this specific geometry, is also proposed and its utility briefly entertained. The work ends with recommendations and suggestions for future works on this topic

Foreign Direct Investment (FDI) and Economic Reforms: The South Asian Perspective

The purpose of this paper is to discuss some of the trends and patterns of foreign direct investment (FDI) inflow in four South Asian countries namely Bangladesh, India, Pakistan and Sri Lanka. The impact of major economic liberalization reforms on inward FDI will also be analyzed at the end. In this paper, panel data estimation is conducted in the empirical analysis of impact of economic reforms on FDI in South Asia (SA). The paper is organized as it follows: In the first part, basic trends and patterns of FDI inflow for four major economies in SA will be discussed. In the second section, economic liberalization reforms and their impact on inward FDI of the above South Asian nations will be examined using panel data estimation. The final section concludes the paper.

Evaluation of Undrained Shear Strength and Soil Classification from Cone Penetration Test

The in-situ cone and piezocone penetration tests (CPT, PCPT) has been widely used by the geotechnical engineering community for subsurface soil characterization and classification, and for the evaluation of many engineering soil properties, such as undrained shear strength (su), unit weight (γ), constrained modulus (M), coefficient of consolidation (cv), and stress history (OCR). The objective of this research study was to estimate the undrained shear strength of clayey soil using CPT/PCPT data in addition to some soil boring log data. At the same time, soil classification charts/methods based on CPT/PCPT were investigated and modified. For this purpose, 70 cone penetration test data collected from 14 different parishes in Louisiana were analyzed. In each site, both laboratory and CPT tests were performed at the same location in order to evaluate the soil parameters (e.g., corrected cone tip resistance, qt; sleeve friction, fs; total overburden pressure, σvo; plasticity index, Ip; Liquid limit, LL; and moisture content, MC). Both linear and non-linear statistical regression models were developed and verified using the measured soil parameters to estimate su of clayey soil for individual soil layers. The su model that contains qt, fs, and σv0 parameters is found to be the best model that satisfies all the statistical parameters, and that the estimated values of su are close to the measured values. In addition, three basic soil zones (e.g., sandy, silty and clayey) have been modified in some CPT/PCPT based soil classification charts. The CPT/PCPT soil classification charts investigated in this study include Douglas and Olsen (1981) chart, modified Schmertmann chart by Tumay (1985), Robertson (1990, 2009 and 2010) charts, Saye et al. (2017) chart, and Zhang and Tumay (1999) probability method. Among these charts, the Robertson (2010) chart showed better prediction to categorize soils for Louisiana. In addition, the Zhang and Tumay (1999) probability method is found to be suitable to categorize the sandy and clayey soil type behavior, but was not so clear for the silty soil behavior

An Empirical Investigation of the Impact of Foreign Remittances on Poverty in Developing Countries

Remittances sent to home countries by migrant workers became significant in amount. Such funds can have profound implications for economic development, human welfare and poverty reduction in a developing country context. This paper examines the impact of foreign remittances on poverty in selected developing countries. A set of time series data has been utilized to empirically check the relationship between remittances and poverty for a list of 44 developing countries worldwide. For the purpose of the study, the ‘Three Stage Least Squares’ (TSLS) regression technique has been applied. A separate analysis for a group of countries among the list which recorded a remittances to GDP ratio of 2% or more has been performed. The study finds that remittances have a significant negative impact on poverty in a developing country