Speed & Torque Vector Control of Induction Motors with Fuzzy Logic Controller

Bahram-Kimiaghalam,Meisam-Rahmani,Hassan-Halleh 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

This paper presents a hybrid Fuzzy Logic Controller (FLC) with vector-control method for induction motors. The vector-control method has been improved by using FLC instead of a simple PD controller. In this hybrid controller high quality regulation is achieved through utilization of the FLC, while stability of the system during transient and around wide range of operating points are assured through application of the vector-control. The hybrid controller has been validated by applying it to a nonlinear model of the motor.

Phenology, Essential Oil Yield and Quality of Cumin (Cuminum cyminum L.) Affected by Sowing Dates and Plant Densities

Bahram Mirshekari 한국원예학회 2010 Horticulture, Environment, and Biotechnology Vol.51 No.5

Field experiments were conducted for evaluation of effects of sowing dates and plant densities on phenology and essential oil quality of cumin (Cuminum cyminum L.). The experiments were arranged as factorial based on randomized complete block design with sowing the dates of 26<SUP>th</SUP> March, 5<SUP>th</SUP>, 15<SUP>th</SUP> and 25<SUP>th</SUP> April, and densities as 25.0, 31.3, 41.7 and 62.5 plants.m<SUP>-2</SUP>. Results showed that the lowest growth period was on 25<SUP>th</SUP> April. Plants sown on 26<SUP>th</SUP> March had greater seed yield than those sown on later sowing dates. The earliest sowing date produced the largest seeds with a thousand seed weight of 3 g. The treatment of 26<SUP>th</SUP> March × 62.5 plants.m<SUP>-2</SUP> produced higher essential oil. Among tested independent variables, seed yield showed a significant effect on essential oil yield. Essential oil content improved 7.55 × 10<SUP>-3</SUP> mL.m<SUP>-2</SUP> per ㎏, increasing seed yield of cumin. Plant density did not show any considerable effect on the essential oil components of cumin. Delaying in sowing date caused a significant effect on cuminaldehyde concentration in essence; thus, a maximum value was obtained from 26<SUP>th</SUP> March and 5<SUP>th</SUP> April sowings. For successful seed production and higher essential oil quantity and quality, cumin must be sown until late March (26<SUP>th</SUP> March) with density of 62.5 plants.m<SUP>-2</SUP> in Tabriz region.

NONLINEAR DEPENDENCIES IN CURRENCY FUTURES

Bahram Adrangi,Arjun Chatrath People&Global Business Association 1999 Global Business and Finance Review Vol.4 No.2

Several studies have documented nonlinear dependencies in the exchange rates of major currencies. This paper provides similar evidence for the currency futures of the British Pound, Deutsche Mark, Swiss Franc, Canadian dollar, and Japanese Yen. It is established that the GARCH (1,1) model satisfactorily explains the nonlinear dependencies in the contracts investigated. Neither trading-volume/open-interest, nor the time to maturity or the basis are found to explain the GARCH effects in the data. However, the conditional volatility in the currency futures' is positively related to futures trading activity and the basis. Finally, we find no support for Samuelson's maturity hypothesis.

DYNAMIC RELATIONSHIP BETWEEN EQUITY PRICES AND MACROECONOMIC CONDITIONS: EVIDENCE FROM EMERGING MARKETS

Bahram Adrangi,Kambiz Raffiee,Todd M Shank People&Global Business Association 2001 Global Business and Finance Review Vol.6 No.2

In this paper we consider two emerging equity markets of Chile and Mexico. The purpose is to examine the responses of equity prices to macroeconomic shocks and policy changes. Employing cointegration test and impulse response analysis, the degree of weak form efficiency in these markets is also examined. Our findings indicate that although equity markets of Mexico and Chile are becoming increasingly more efficient in incorporating the past information, they do not reflect shocks to macroeconomic conditions rapidly. Empirical findings also show that the equity market of Chile has achieved higher degree of efficiency than the equity market of Mexico. These findings have implications for individual and institutional investors in the U.S. and domestic policy makers of these markets.

EUROPEAN EMERGING MARKETS AND THE WORLD MARKET VOLATILITY

Bahram Adrangi,Kambiz Raffiee,Todd Shank People&Global Business Association 1999 Global Business and Finance Review Vol.4 No.1

This paper examines the volatility persistence in three European emerging markets, Greece, Portugal, and Spain. Monthly value weighted index returns are computed and analyzed. A moving average TARCH model which accounts for asymmetry is estimated. Our findings show that the asymmetric influence of the positive and negative news in the previous month is statistically significant in all markets but Spain. In all markets the previous month's volatility has a significant effect on the volatility in the current month. All markets show high volatility persistence relative to the world market. Among the equity markets analyzed, Lisbon stock index shows the highest volatility persistence and the Spain index the lowest. Returns and systematic risk in markets of Greece and Spain are directly related to the world market. However, Granger tests of causality suggests that there is a bi-causal relationship between the world market returns and market returns in Spain. The findings may have significant implications for portfolio diversification strategies when investing in European emerging markets.

Nonlinear Dependencies And Chaos In The Exhange Rate Of The Dollar

Bahram Adrangi,Mary Allender,Arjun Chatrath,Kambiz Raffiee 사람과세계경영학회 2008 Global Business and Finance Review Vol.13 No.1

Employing the daily broad dollar index we conduct a battery of tests for the presence olfow-dimension chaos. The dollar index return series is subjected tu Correlation Dimension tests, EDS tests, and tests fi1r entropy. While wefind strong evidence ofnonlinear dependence in the data, the evidence is not consistent with chaos. Our test results indicate that a GARCH process explains the nonlinearities in the data. We also show that employing seasonally adjusted index series enhances the robustness ofresults via the existing tests for chaotic structure.

Extraction of alkali metals using emulsion liquid membrane by nano-baskets of calix[4]crown

Bahram Mokhtari,Kobra Pourabdollah 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study is the application of nano-baskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of diacid calix[4]-1,2-crowns were synthesized, and their inclusion-extraction parameters were optimized including the calixcrown scaffold (13, 4 wt%) as the carrier/demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8and 0.3, mixing speed (300 rpm), and initial solute concentration (100mg/L). The selectivity of membrane over more than ten interfering cations was examined and the results revealed that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.

Effect of Crown Ring Size and Upper Moiety on the Extraction of s-Block Metals by Ionizable Calixcrown Nano-baskets

Bahram Mokhtari,Kobra Pourabdollah 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.11

Eight ionizable nano-baskets of cone 25,26-di(carboxymethoxy)calix[4]arene-crown-3,4,5,6 were synthesized and were verified by ^1H and ^13C NMR spectroscopy, IR spectroscopy and elemental analysis. The competitive solvent extractions of alkali and alkaline earth metal cations were studied using such nano-baskets. The novelty of this study is including three binding units of calixarene's bowl, crown ether's ring and electron-donor ionizable moieties in a unique scaffold to assess the binding tendency towards the cations. The objective of this work is to study the extraction efficiency, selectivity and pH½ of such complexes. The result of solvent extraction experiments indicated that these compounds were effective extractants of alkali and alkaline earth metal cations. Their selectivities were greatly influenced by the acidity of solution and the conformations of the calixcrown. One conformer was selective to Na+ in pH ≥ 4, while the other was highly selective to Ba(2+) in pH 6 and upper.

Proposing an Elliptic Equation for the Symmetrical Sag Vertical CurvesBased on Sight Distance in Highway

Bahram Shirini,Ali Abdi Kordani 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.12

The sight distance at night is one of the most important driving safety factors. Sag vertical curves are one of the important elements of roads, which require a sufficient sight distance at night. The headlight sight distance is used for determining the length of the sag vertical curves. Presently, the parabolic curve is mainly used in symmetrical sag vertical curves. The present study aimed to propose the elliptic curve as a new alternative for the parabolic curve. An elliptic equation is developed for use in vertical curve and sight distance of the sag elliptic vertical curve in nighttime is calculated based on the characteristics of the road geometry. Results indicate that contrary to the parabolic curve, the sight distance of the elliptic curve varies depending on the vehicle location and increases as the vehicle moves forward on the curve; therefore, driver sees the end of curve in elliptic curves much earlier than parabolic curves. The results also indicate that the sight distance of the parabolic curve is more than that of the elliptic curve in the shortest length after the curve beginning (up to 8% of the curve length) while the sight distance of the elliptic curve is more than that of the parabolic curve at the rest of the curve (at least 92% of the curve length). Based on the obtained results, for S > L, the stopping sight distances of the elliptic and parabolic vertical curves are equal.

Study of QTLs linked to awn length and their relationships with chloroplasts under control and saline environments in bread wheat

Bahram Masoudi,Mohsen Mardi,Eslam Majidi Hervan,Mohammad Reza Bihamta,Mohammad Reza Naghavi,Babak Nakhoda,Behnam Bakhshi,Mehrzad Ahmadi,Mohammad Taghi Tabatabaei,Mohamad Hossein Dehghani Firouzabadi 한국유전학회 2019 Genes & Genomics Vol.41 No.2

Introduction Some studies in wheat showed that awns may have a useful effect on yield, especially under drought stress. Up to this time few researches has identified the awn length QTLs with different effect in salinity stress. Objective The primary objective of this study was to examine the additive (a) and the epistatic (aa) QTLs involve in wheat awns length in control and saline environments. Methods A F7 RIL population consisting of 319 sister lines, derived from a cross between wheat cultivars Roshan and Falat (seri82), and the two parents were grown in two environments (control and Saline) based on an alpha lattice design with two replications in each environment. At flowering, awn length was measured for each line. For QTL analysis, the linkage map of the ‘‘Roshan × Falat’’ population was used, which included 748 markers including 719 DArT, 29 simple sequenced repeats (SSRs). Additive and pleiotropic QTLs were identified. In order to reveal the relationship between the identified QTL for awns length and the role of the gene or genes that it expresses, the awns length locus location and characteristics of its related CDS, gene, UTRs, ORF, exons and Introns were studied using ensemble plant (http://plant s.ensem bl.org/Triti cum_aesti vum). Furthermore, the promoter analysis has been done using NSITE-PL. Results We identified 6 additive QTLs for awn length by QTL Cartographer program using single-environment phenotypical values. Also, we detected three additive and two epistatic QTLs for awn length by the QTLNetwork program using multienvironment phenotypical values. Our results showed that none of the additive and epistatic QTLs had interactions with environment. One of the additive QTLs located on chromosome 4A was co-located with QTLs for number of sterile spikelet per spike in both environment and number of seed per spike in control environment. Coclusion Studies of the locus linked to the awns length QTL revealed the role of awn and its chloroplasts in grain filing during abiotic stress could be enhanced by over expression of some genes like GTP-Binding proteins which are enriched in chloroplasts encoded by genes included wPt-5730 locus.