Implementation of Fast technique for Unit Commitment Based on Unit Clustering

A new approach to the problem of large scale unit commitment is presented in this paper. The units are classified into various clusters based on their similar characteristics in order to reduce the computational time and also to satisfy the minimum up/down constraints easily. Unit commitment problem is an important optimizing task in daily operational planning of power systems which can be mathematically formulated as a large scale nonlinear mixed-integer minimization problem. A new methodology employing the concept of cluster algorithm called as additive and divisive hierarchical clustering has been employed along with particle swarm optimization in order to carry out the technique of unit commitment. Proposed methodology involves two individual algorithms. While the load is increasing, additive cluster algorithm has been employed while divisive cluster algorithm is used when the load is decreasing. The proposed technique is tested on a 10 unit system and the simulation results show the performance of the proposed technique. Keywords: Unit commitment, additive clustering, divisive clustering, Lambda iteration method

Comparison of Performance of SSSC and TCPS in Automatic Generation Control of Hydrothermal System Under Deregulated Scenario

This paper presents the modelling and simulation of Static Synchronous Series Compensator (SSSC) in a two area system for Automatic Generation Control (AGC) under deregulated environment. The modelling of Thyristor Controlled phase Shifter (TCPS) is also carried out and comparison is made between SSSC and TCPS. A two area hydrothermal system under deregulated environment has been considered for this purpose.  The devices are modeled and attempt has been made to incorporate these devices in the two area system thus improving the dynamic response of the system. The effect of these parameters on the system is demonstrated with the help of computer simulations. A systematic method has also been demonstrated for the modeling of this component in the system. Computer simulations reveal that due to the presence of SSSC along with TCPS, the dynamic performance of the system in terms of settling time, overshoot is greatly improved than that of without SSSC.DOI:http://dx.doi.org/10.11591/ijece.v1i1.2

Fuel-optimal trajectories of aeroassisted orbital transfer with plane change

The problem of minimization of fuel consumption during the atmospheric portion of an aeroassisted, orbital transfer with plane change is addressed. The complete mission has required three characteristic velocities, a deorbit impulse at high earth orbit (HEO), a boost impulse at the atmospheric exit, and a reorbit impulse at low earth orbit (LEO). A performance index has been formulated as the sum of these three impulses. Application of optimal control principles has led to a nonlinear, two-point, boundary value problem which was solved by using a multiple shooting algorithm. The strategy for the atmospheric portion of the minimum-fuel transfer is to start initially with the maximum positive lift in order to recover from the downward plunge, and then to fly with a gradually decreasing lift such that the vehicle skips out of the atmosphere with a flight path angle near zero degrees

4-[(5R*,10bR*)-2-Methyl-1,10b-dihydro­pyrazolo[1,5-c][1,3]benzoxazin-5-yl]benzoic acid

In the title compound, C18H16N2O3, a potential inhibitor of the cyclo­oxygenase-2 isoenzyme, the pyrazoline ring exists in a flattened envelope conformation with one C atom deviating by 0.463 Å from the mean plane of the remaining four atoms. The puckering of the central oxazine ring is more severe, with one N atom and one C atom displaced by 0.235 (6) and 0.370 (2) Å, respectively, on opposite sides of the mean plane defined by the other four atoms; the conformation is that of a half-chair. As a result, the mol­ecule as a whole is not planar. The carboxyl group is involved in an inter­molecular O—H⋯N hydrogen bond, which links the mol­ecules into centrosymmetric dimers

2-Methyl-1,10b-dihydro-5H-pyrazolo[1,5-c][1,3]benzoxazin-5-one

In the title compound, C11H10N2O2, a potential inhibitor of the cyclo­oxygenase-2 isoenzyme, the pyrazoline ring exists in a flat-envelope conformation while the puckering of the central oxazine ring is more severe. As a result, the mol­ecule as a whole is non-planar. The formal sp 3 pyrazoline N atom is sp 2 hybridized, with the lone-pair electrons delocalized through conjugation with the carbonyl group rather than the double bond of the pyrazoline ring

Techno-economic Study by Teaching Learning-based Optimization Algorithm for Optimal Placement of DG Units in Distribution Systems

A significant improvement in system performance can be achieved by placing Distributed Generator (DG) units of the optimal size in optimum network of radial distribution locations. In order to maximize the economic and technological benefits, it is necessary to reduce yearly economic losses. These losses include expenditures associated with installation and operation of the buses as well as power loss and voltage difference between buses. In view of these multi-objective frameworks, the current problem is assessed and the best compromise solution also referred as the Pareto-optimal solution is provided. In the framework of the multi-objective optimization problem, specific equality as well as inequality constraints is investigated. It is shown in this study that a Multi-Objective Teaching-Learning Based Optimization (MOTLBO) algorithm has been proposed to solve the multi-objective problem. For the purpose of evaluating its performance, the proposed method is being deployed on IEEE-33 and IEEE-69 System of radial bus distribution. A comparison with other recent multi-objective algorithms such as OCDE, KHA and LSFSA is also included in this study. It has been revealed that the algorithm proposed can offer superior outcomes concerning power loss, annual economic loss mitigation and voltage profile enhancement

Cyclic AMP increases COX-2 expression via mitogen-activated kinase in human myometrial cells

Cyclic AMP (cAMP) is the archetypal smooth muscle relaxant, mediating the effects of many hormones and drugs. However, recently PGI2, acting via cAMP/PKA, was found to increase contraction-associated protein expression in myometrial cells and to promote oxytocin-driven myometrial contractility. Cyclo-oxygenase-2 (COX-2) is the rate-limiting enzyme in prostaglandin synthesis, which is critical to the onset and progression of human labour. We have investigated the impact of cAMP on myometrial COX-2 expression, synthesis and activity. Three cAMP agonists (8-bromo-cAMP, forskolin and rolipram) increased COX-2 mRNA expression and further studies confirmed that this was associated with COX-2 protein synthesis and activity (increased PGE2 and PGI2 in culture supernatant) in primary cultures of human myometrial cells. These effects were neither reproduced by specific agonists nor inhibited by specific inhibitors of known cAMP-effectors (PKA, EPAC and AMPK). We then used shRNA to knockdown the same effectors and another recently described cAMP-effector PDZ-GEF1-2, without changing the response to cAMP. We found that MAPK activation mediated the cAMP effects on COX-2 expression and that PGE2 acts through EP-2 to activate MAPK and increase COX-2. These data provide further evidence in support of a dual role for cAMP in the regulation of myometrial function

Hsp90 and PKM2 Drive the Expression of Aromatase in Li-Fraumeni Syndrome Breast Adipose Stromal Cells

Li-Fraumeni syndrome (LFS) patients harbor germ line mutations in the TP53 gene and are at increased risk of hormone receptor-positive breast cancers. Recently, elevated levels of aromatase, the rate-limiting enzyme for estrogen biosynthesis, were found in the breast tissue of LFS patients. Although p53 down-regulates aromatase expression, the underlying mechanisms are incompletely understood. In the present study, we found that LFS stromal cells expressed higher levels of Hsp90 ATPase activity and aromatase compared with wild-type stromal cells. Inhibition of Hsp90 ATPase suppressed aromatase expression. Silencing Aha1 (activator of Hsp90 ATPase 1), a co-chaperone of Hsp90 required for its ATPase activity, led to both inhibition of Hsp90 ATPase activity and reduced aromatase expression. In comparison with wild-type stromal cells, increased levels of the Hsp90 client proteins, HIF-1α, and PKM2 were found in LFS stromal cells. A complex comprised of HIF-1α and PKM2 was recruited to the aromatase promoter II in LFS stromal cells. Silencing either HIF-1α or PKM2 suppressed aromatase expression in LFS stromal cells. CP-31398, a p53 rescue compound, suppressed levels of Aha1, Hsp90 ATPase activity, levels of PKM2 and HIF-1α, and aromatase expression in LFS stromal cells. Consistent with these in vitro findings, levels of Hsp90 ATPase activity, Aha1, HIF-1α, PKM2, and aromatase were increased in the mammary glands of p53 null versus wild-type mice. PKM2 and HIF-1α were shown to co-localize in the nucleus of stromal cells of LFS breast tissue. Taken together, our results show that the Aha1-Hsp90-PKM2/HIF-1α axis mediates the induction of aromatase in LFS

Seaweed resources of the Tuticorin-Tiruchendur coast, Tamil Nadu, India

The southern coast of Tamil Nadu (Mandapam to Kanyakumari) supports luxuriant growth of economic seaweeds. The entire indigenous phycocoUoid industry of the country gets the raw material from this region and during the last two decades, due to indiscriminate harvesting, there has been over-exploitation of the resource. The present paper deals with survey conducted in the first sector from Tuticorin to Tiruchendur during December 1986—March 1987. In this study 58 species of marine algae were recorded of which 7 belong to Chlorophyta, 12 to Phaeophyta and 39 to Rhodophyta besides 3 species of seagrasses namely Cymodocea seiriilata, Halophila ovalis and //. ovata within 650 sq. km area surveyed. The total standing crop of the seaweeds was estimated at 9,100 tonnes (wt.). The estimates for the dominant species are Dictyota maxima 530 t, Sargassum tenerrium 640 t, D. bartayresiana 8601, Selieria rebusta 2,0901 and Hypnea valemiae 2,4301. The seaweed potential for commercial exploitation has been briefly discussed