Optimal Robot Arm Movement using Tabu Search Algorithm

Abstract: This study presents an optimum approach to calculate the optimal robot arm movement for processing a considerable commitment of tasks using Tabu Search (TS) algorithm. In the scheduling problem, the objective is to minimize the total processing time related to tasks distances from each other. In the first step, the TS method is reviewed and we employ the proposed method in order to assign efficiently the optimal robot arm movement. In our proposed algorithm, the crossover rate is large at first and gradually it is decreased based on convergence improvement in next generations. We define an objective function including the operation times. Then, by minimizing this function using discrete TS algorithm, the optimal robot arm movement trajectory is assigned efficiently and quickly. If the resulted best cost converges to global minima, the crossover rate will be decreased in next generation. This method is studied in terms of operation time, convergence speed and quality of the results. Superior features of this algorithm are fast tuning, rapid convergence, less computational burden and capability to avoid from local minima. High promising results demonstrate that our proposed method is very efficient and can obtain higher quality solutions with better computational capability

Quenching of acoustic bandgaps by flow noise

Copyright (2009) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics along with the following message: The following article appeared in Appl. Phys. Lett. 94, 134104 (2009) and may be found at http://dx.doi.org/10.1063/1.3111797. Authors own version of final article on e-print serversWe report an experimental study of acoustic effects produced by wind impinging on noise barriers based on two-dimensional sonic crystals with square symmetry. We found that the attenuation strength of sonic-crystal bandgaps decreases for increasing values of flow speed. A quenching of the acoustic bandgap appears at a certain speed value that depends of the barrier filling ratio. For increasing values of flow speed, the data indicate that the barrier becomes a sound source because of its interaction with the wind. We conclude that flow noise should be taken into account in designing acoustic barriers based on sonic crystals.This work was supported by the Spanish Agency of International Cooperation (AECI), the Spanish Ministry of Science and Innovation (MICIIN), and the Spanish Ministry of Public Works (MF). J.S.-D. acknowledges useful conversations with A. Broatch.Elnady, T.; Elsabbagh, A.; Akl, W.; Mohamady, O.; Garcia Chocano, VM.; Torrent Martí, D.; Cervera Moreno, FS.... (2009). Quenching of acoustic bandgaps by flow noise. Applied Physics Letters. 94(13). doi:10.1063/1.3111797S9413Sánchez-Pérez, J. V., Caballero, D., Mártinez-Sala, R., Rubio, C., Sánchez-Dehesa, J., Meseguer, F., … Gálvez, F. (1998). Sound Attenuation by a Two-Dimensional Array of Rigid Cylinders. Physical Review Letters, 80(24), 5325-5328. doi:10.1103/physrevlett.80.5325Rubio, C., Caballero, D., Sanchez-Perez, J. V., Martinez-Sala, R., Sanchez-Dehesa, J., Meseguer, F., & Cervera, F. (1999). The existence of full gaps and deaf bands in two-dimensional sonic crystals. Journal of Lightwave Technology, 17(11), 2202-2207. doi:10.1109/50.803012Caballero, D., Sánchez-Dehesa, J., Rubio, C., Mártinez-Sala, R., Sánchez-Pérez, J. V., Meseguer, F., & Llinares, J. (1999). Large two-dimensional sonic band gaps. Physical Review E, 60(6), R6316-R6319. doi:10.1103/physreve.60.r6316Caballero, D., Sánchez-Dehesa, J., Martínez-Sala, R., Rubio, C., Sánchez-Pérez, J. V., Sanchis, L., & Meseguer, F. (2001). Suzuki phase in two-dimensional sonic crystals. Physical Review B, 64(6). doi:10.1103/physrevb.64.064303Chen, Y.-Y., & Ye, Z. (2001). Acoustic Attenuation by Two-Dimensional Arrays of Rigid Cylinders. Physical Review Letters, 87(18). doi:10.1103/physrevlett.87.184301Sanchez-Perez, J. V., Rubio, C., Martinez-Sala, R., Sanchez-Grandia, R., & Gomez, V. (2002). Acoustic barriers based on periodic arrays of scatterers. Applied Physics Letters, 81(27), 5240-5242. doi:10.1063/1.1533112Goffaux, C., Maseri, F., Vasseur, J. O., Djafari-Rouhani, B., & Lambin, P. (2003). Measurements and calculations of the sound attenuation by a phononic band gap structure suitable for an insulating partition application. Applied Physics Letters, 83(2), 281-283. doi:10.1063/1.1592016Goffaux, C., & Vigneron, J. P. (2001). Theoretical study of a tunable phononic band gap system. Physical Review B, 64(7). doi:10.1103/physrevb.64.075118Zhong, L., Wu, F., Zhang, X., Zhong, H., & Zhong, S. (2005). Effects of orientation and symmetry of rods on the complete acoustic band gap in two-dimensional periodic solid/gas systems. Physics Letters A, 339(1-2), 164-170. doi:10.1016/j.physleta.2005.03.025Umnova, O., Attenborough, K., & Linton, C. M. (2006). Effects of porous covering on sound attenuation by periodic arrays of cylinders. The Journal of the Acoustical Society of America, 119(1), 278-284. doi:10.1121/1.2133715Martínez-Sala, R., Rubio, C., García-Raffi, L. M., Sánchez-Pérez, J. V., Sánchez-Pérez, E. A., & Llinares, J. (2006). Control of noise by trees arranged like sonic crystals. Journal of Sound and Vibration, 291(1-2), 100-106. doi:10.1016/j.jsv.2005.05.030Sanchis, L., Håkansson, A., Cervera, F., & Sánchez-Dehesa, J. (2003). Acoustic interferometers based on two-dimensional arrays of rigid cylinders in air. Physical Review B, 67(3). doi:10.1103/physrevb.67.03542

Performing the Egyptian revolution : origins of collective restraint action in the Midan

This research was supported by a Carnegie Trust for the Universities of Scotland grant.In January/February 2011, the world watched with admiration the Egyptian revolution that toppled President Housni Mubarak. The demonstration in Midan al-Tahrir (Liberation Square in central Cairo), which was the nucleus of the revolution, highlighted a largely spontaneous, civil and peaceful political performance. However, this performance was temporary, contradicting subsequent bloody conflicts in post-revolutionary Egypt. This article examines the socio-political origins of the Midan performance. It argues that the demonstrators exercised collective restraint, which was temporary but necessary, in order to topple Mubarak. Building on Norbert Elias’ civilising process theory and social movements literature, it is argued that the origins of this performance are found in a collective knowledge of regime strategy and narrative, Egyptian socio-political values and existing repertoires of contention. Drawing on primary sources and semi-structured interviews, the article contends that the demonstrators exercised collective restraint to reframe regime narrative and draw public support for the revolution.PostprintPeer reviewe

Burden of rotavirus gastroenteritis in the Middle Eastern and North African pediatric population

<p>Abstract</p> <p>Background</p> <p>Rotavirus gastroenteritis (RVGE) is the most common cause of severe childhood diarrhea worldwide. Objectives were to estimate the burden of RVGE among children less than five years old in the Middle East (Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, Syria, UAE, Yemen), North Africa (Algeria, Egypt, Libya, Morocco, Tunisia) and Turkey.</p> <p>Methods</p> <p>A comprehensive literature search was conducted in major databases on the epidemiology and burden of rotavirus among children less than five years old between 1999 and 2009. Data from each country was extracted and compared.</p> <p>Results</p> <p>The search identified 43 studies. RVGE was identified in 16-61% of all cases of acute gastroenteritis, with a peak in the winter. RVGE-related hospitalization rates ranged from 14% to 45%, compared to 14%-28% for non-RVGE. Annually, RVGE caused up to 112 fatalities per 100,000 in certain countries in the region. Hospitalization costs ranged from $1.8 to$4.6 million annually, depending on the country. The most recent literature available showed that G1P[8] was the most prevalent genotype combination in 8 countries (range 23%-56%). G2P[4] was most prevalent in 4 countries (26%-48%). G9P[8] and G4P[8] were also frequently detected.</p> <p>Conclusions</p> <p>RVGE is a common disease associated with significant morbidity, mortality, and economic burden. Given the variety and diverse rotavirus types in the region, use of a vaccine with broad and consistent serotype coverage would be important to help decrease the burden of RVGE in the Middle East and North Africa.</p

Improving Weak Subgrade Soil Using Different Additives

Weak subgrade is the main problem facing most highway projects. Therefore, this study focuses on trying to improve the properties and increase the strength of weak, clayey, swelling soil for use as a subgrade for pavement structural sections. This trial was developed using a mix of granular and chemical stabilization for the soil. Granular stabilization was applied firstly by mixing natural sand at different percentages of 20%, 35%, and 50% of the total weight of clayey, swelling soil samples to find the minimum percentage that could be added to improve it to sandy, clayey soil, which is acceptable as a subgrade according to the Egyptian highway specification code. Secondly, chemical stabilization was applied to enhanced sandy, clayey soil to increase its strength properties. This was performed by adding chemical additives (lime, cement kiln dust (CKD), fiberglass, Addicrete 11, and gypsum) at different ratios of 2%, 4%, and 6% of the total weight of the samples of enhanced sandy, clayey soil. An experimental program was conducted consisting of characteristics and consistency tests, the California bearing ratio (CBR) test, a proctor test, and a consolidated-drained (C-D) tri-axial shear test. The results showed that 50% sand was the minimum percentage that could be mixed with swelling, clayey soil for granular stabilization to be enhanced and become sandy, clayey soil, which is accepted as a subgrade layer according to the Egyptian highway specification code. In addition, using a mix of granular and chemical stabilization increased the compressive strength of this enhanced subgrade by adding 6% lime or cement kiln dust (CKD) of the total sample weight. They enhanced the strength of the soil and reduced its plasticity. Adding 6% fiberglass and polymers could slightly enhance the desired properties; however, it is not recommended to use them due to their slight effect and economic cost. In addition, it is not recommended to use gypsum at more than 4% due to its negative effect on CBR

Factors affecting the production of lactulose by Lactobacillus acidophilus NRRL 4495 β-galactosidase and its biological activity

Aim: Production of lactulose and other oligosaccharides by Lactobacillus acidophilus NRRL 4495 â-galactosidase andtheir biological activity. Methodology and Results: The transgalactosylation activity of Lactobacillus acidophilus NRRL 4495 B-galactosidase was investigated under different conditions for synthesis of lactulose and oligosaccharides. The synthesis was optimized with respect to pH; time; enzyme concentration and substrates ratio (lactose: fructose). Maximum production forlactulose was found to be 25 g/L at pH 6.6 with 40: 20% (w/v) lactose to fructose, respectively and enzyme concentration 4 IU/mL after 7 h. With respect to the other oligosaccharides the maximum yield (19 .68 g/L) was obtained under the same conditions but with enzyme concentration 2 IU/mL and after 10 h. As a new pharmaceutical application the produced lactulose and oligosaccharide and their sulfated derivative were found to have fibrinolytic activity, but theyfailed to act as anticoagulant. Conclusion significance and impact of study: the research leads to increase the production of lactulose and other oligosaccharides with a significant yield and discovered a new pharmaceutical application for all the products

Antitumor activity of 5-fluorouracil polymeric nanogel synthesized by gamma radiation on a rat model of colon carcinoma: a proposed mechanism

Abstract The use of 5-fluorouracil (5-FU) is associated with multifaceted challenges and poor pharmacokinetics. Accordingly, our study was designed to prepare 5-FU nanogel as a new form of the colon cancer chemotherapeutic drug 5-FU using polyacrylic acid and gelatin hybrid nanogel as efficient drug carriers. Alongside the in vivo chemotherapeutic evaluation, the anti-proliferative and anti-apoptotic efficacy were carried out for 5-FU nanogel against 1,2-dimethylhydrazine (DMH, 20 mg/kg) and γ-radiation (4 Gy)-prompted colon dysplasia in rats compared to 5-FU. The morphology and size of 5-FU nanogel were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) in addition to cytotoxicity assay. The expression of phosphoinositide-3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR); Toll-like receptor2 (TLR2)/nuclear factor kappa B), adenosine monophosphate (AMP)-activated protein kinase (AMPK) and its downstream autophagy-related genes in addition to apoptotic markers were measured in colon tissues. Results: 5-FU nanogel reduced the levels of the TLR2/ NF-κβ as well as the expression of PI3K/AKT/mTOR. Moreover, it promoted autophagy through the activation of the AMPK and its downstream targets which consequently augmented the intrinsic and extrinsic apoptotic pathways. Conclusion: Collectively, these data might strengthen the therapeutic potential of 5-FU nanogel which can be used as an antitumor product for colon cancer

Synthesis and characterization of poly(carboxymethyl)-cellulose for enhanced La(III) sorption

International audienceThe grafting of amino and carboxylic acid groups on cellulose increased La(III) sorption efficiency of cellulose: maximum sorption capacity increased from 38 mg La g(-1) for cellulose to 101 and 170 mg La g(-1) for amino derivative (PAC) and amino-carboxylic derivative (PCMC). Langmuir equation successfully fits sorption isotherms while uptake kinetics are effectively modeled using the pseudo-first order rate equation (though resistance to intraparticle diffusion plays a significant role in the control of metal recovery). Uptake equilibrium occurred within 150-180 min. The thermodynamic study shows that the reaction is spontaneous, endothermic and entropic. Nitric acid solutions (0.5 M concentration) can be efficiently used for metal recovery and sorbent can be recycled for at least 5 cycles with limited decrease in sorption performance for the three sorbents. The materials were characterized by elemental analysis, acid-base titration, FTIR spectrometry, x-ray diffraction analysis, X-ray photoelectron spectroscopy, SEM-EDX analysis and also by TGA