Superluminal light group velocity in tapered optical microfibers

Superluminal light group velocity was formerly reported in anomalous dispersion, nonlinear amplification of light pulse, high-gain lasers' cavities, and waveguides. Motivated by a recent observation of light acceleration in optical microfiber [1], the possibility of attaining the light group velocity exceeds its value in vacuum is investigated. The investigation of superluminal velocity is in tapered optical microfiber that has a radius decreases with propagation axis by a factor 10-3. Our results show the possibility of attaining superluminal group velocity in this microfiber at length of about 1080µm. At this length the instantaneous acceleration of light is found to be 13×1019 m/s2 which its corresponding Unruh temperature is 0.527K

Early detection of Aspergillus carbonarius and A. niger on table grapes: a tool for quality improvement

Aspergillus carbonarius and A. niger aggregate are the main fungal contaminants of table grapes. Besides their ability to cause black rot, they can produce ochratoxin A (OTA), a mycotoxin that has attracted increasing attention worldwide. The objective of this work was to set up a simple and rapid molecular method for the early detection of both fungi in table grapes before fungal development becomes evident. Polymerase chain reaction (PCR)-based assays were developed by designing species-specific primers based on the polyketide synthases (PKSS) sequences of A. carbonarius and A. niger that have recently been demonstrated to be involved in OTA biosynthesis. Three table grape varieties (Red globe, Crimson seedless, and Italia) were inoculated with A. carbonarius and A. niger aggregate strains producing OTA. The extracted DNA from control (non-inoculated) and inoculated grapes was amplified by PCR using ACPKS2F-ACPKS2R for A. carbonarius and ANPKS5-ANPKS6 for A. niger aggregate. Both primers allowed a clear detection, even in symptomless samples. PCR-based methods are considered to be a good alternative to traditional diagnostic means for the early detection of fungi in complex matrix for their high specificity and sensitivity. The results obtained could be useful for the definition of a 'quality label' for tested grapes to improve the safety measures taken to guarantee the production of fresh table grapes

Maximum intensity determination of beam waist in BBO optical nonlinear crystal using single harmonic generation

Nonlinear optics is a branch of optics that explains the nonlinear response of atoms and molecules to a field of light radiation. There is a difficulty in cutting crystals in shapes commensurate with their optical properties, and thus it was significant to determine the descriptive shape of crystal properties based on its optic properties to be ideal in use. The problem of determining the length of the crystal to give the best output power is still under study and research and is one of the most important topics. In our research, a computational method based on mathematical relationships was used to estimate the length of the BBO crystal of I-type, which gives the best output power, by manipulating the location of the optical light scattering to be in the middle of the crystal. It was found that the best length of a crystal with a width of 3mm and a height of 3mm is 7mm. the comparison of these results with the previous literatures gave a great match, which confirms the correctness of the computations and the reliability of used method

Comparison Mechanical Properties of Two Types of Light Weight Aggregate Concrete

This paper presents the behavior of concrete properties by replacing the conventional coarse aggregate used in the concrete mixture by two types of lightweight aggregate; Expanded Perlite Aggregate (EPA) and Volcanic Pumice (VP). To fulfill this aim; three laboratory tests were applied; density, compressive strength, and abrasion resistance, that conducted to extrapolate the range of the changes in the properties of concrete with existence those types of aggregate in the mixture. Also, the volumetric proportion adopted as a strategy for replacing the coarse aggregate by EPA or VP in the concrete mixture. Then, the volumetric proportion ranged from 10% to 50% with the variation step was 10%. Therefore, ten concrete mixtures are prepared and divided into two groups; each group contains five concrete mixes to represent the volumetric replacement (10-50)% of conventional coarse aggregate by EPA or VP. On the other hand, one extra mixture designed by using conventional aggregate (coarse and fine aggregate) without any inclusion of EPA or VP to be considered as a reference mixture. The obtained laboratory results of this study proved that the density, compressive strength, and abrasion resistance readings of concrete decreased at any volumetric proportion replacement of coarse aggregate by EPA or VP. The decrease in density and compressive strength of concrete readings amounted the peak level at 50% replacing of coarse aggregate by EPA, which were 38.19% and 77.37%, respectively than the reference mixture. Additionally, the compressive strength is an important factor affecting the abrasion resistance of concrete mixture, and loss of abrasion decreased as compressive strength increased

FORAGE QUALITY OF MAIZE AND LEGUMES AS MONOCULTURES AND MIXTURES AT DIFFERENT SEED RATIOS

ABSTRACT Livestock is an important sector of agriculture, but good quality forage is one of the major limiting factors for the growth of this industry. Studies were conducted to compare the forage quality of maize and legumes sown in pure stand and in mixture in randomized complete blocks during 2005 and 2006 at the University of Agriculture Faisalabad, Pakistan. Maize (Zea mays L.) and three legumes [cluster bean (Cyamopsis tetragonoloba), cowpea (Vigna unguiculata (L.) Walp.), and sesbania (Sesbania sesban)] were sown at 100% the recommended seeding rate and in maize:legume mixtures at seed ratios (SR) of 75:25, 50:50 and 25:75. Crude protein (CP) and ether extractable fat (EEF) percentage of maize increased with the increase in seeding rate of legumes in all maize-legume mixtures over sole maize. Crude fibre (CF) percentage of forage maize was the maximum in sole maize. All monoculture legumes produced highest CP and EEF percentage than their mixtures with maize. Mixtures of maize-sesbania gave higher CP and EEF than maize-cowpea or maize-cluster bean at similar seed ratios, while cowpea sown alone or in mixture with maize had higher total ash than other legumes at same seed ratios. Farmers may grow maize+sesbania to get good quality forage

Comparison Study of Axial Behavior of RPC-CFRP Short Columns

In this paper, the axial behaviors of reactive powder     concrete (RPC) short  columns confined with carbon fiber reinforced polymer (CFRP) were   investigated. All the specimens have square cross section of 100 mm × 100   mm and length of 400 mm with aspect ratio 4. The experimental work consists   of three groups. The first group consists of six specimens of RPC with 2% micro steel fiber, without ordinary reinforcing steel and confining by zero, one and two layer of CFRP respectively. The second group consists of six    specimens of RPC with 2% micro steel fiber and minimum ordinary reinforcing  steel and confining by zero, one and two layers of CFRP respectively. The third  group consists of four specimens of RPC without micro steel fiber and ordinary  reinforcing steel and confining by one and two layers of CFRP respectively.  Experimental data for strength, longitudinal and lateral displacement and  failure mode were obtained for each test. The toughness (area under the curve) for each test was obtained by using numerical integration. The RPC columns confined with CFRP showed stiffer behavior compared with RPC columns without CFRP. The ultimate load of the RPC columns with 2% micro steel  fiber + two layers of CFRP + minimum ordinary reinforcement were more than that of the RPC columns with 2% micro steel fiber + minimum ordinary   reinforcement and without CFRP by about 1.333. 

A Model for Predicting Entrepreneurship Intentions based on Social Cognitive Theory and Entrepreneurship Characteristics

This research studies whether entrepreneurial characteristics comprising passion, creativity, and self-efficacy are significantly associated with entrepreneurial intentions. Therefore, the final year students from various disciplines from a public university who were potential entrepreneurs and have attended the advance level courses on entrepreneurship were chosen for the data collection. Most of these students have participated in the on-campus business related activities and received some experience through these activities. It was found that there are strong positive correlation between entrepreneurial characteristic factors with entrepreneurial intention. Overall, the R2 of the entrepreneurship’s characteristics comprising entrepreneurial passion, self-efficacy, and creativity to predict entrepreneurship intention to become an entrepreneur shows very strong explanation power. It implies that this studys proposed model can serve as an assessment tool for selecting students with the higher entrepreneurial intention to engage them in entrepreneurship and activities at the university

Synthesis and Identification of New N,N-Disubstituted Thiourea, and Thiazolidinone Scaffolds Based on Quinolone Moiety as Urease Inhibitor

Synthesis of thiazolidinone based on quinolone moiety was established starting from 4-hydroxyquinol-2-ones. The strategy started with the reaction of ethyl bromoacetate with 4-hydroxyquinoline to give the corresponding ethyl oxoquinolinyl acetates, which reacted with hydrazine hydrate to afford the hydrazide derivatives. Subsequently, hydrazides reacted with isothiocyanate derivatives to give the corresponding N,N-disubstituted thioureas. Finally, on subjecting the N,N-disubstituted thioureas with dialkyl acetylenedicarboxylates, cyclization occurred, and thiazolidinone derivatives were obtained in good yields. The two series based on quinolone moiety, one containing N,N-disubstituted thioureas and the other containing thiazolidinone functionalities, were screened for their in vitro urease inhibition properties using thiourea and acetohydroxamic acid as standard inhibitors. The inhibition values of the synthesized thioureas and thiazolidinones exhibited moderate to good inhibitory effects. The structure−activity relationship revealed that N-methyl quinolonyl moiety exhibited a superior effect, since it was proved to be the most potent inhibitor in the present series achieving (IC50 = 1.83 ± 0.79 µM). The previous compound exhibited relatively much greater activity, being approximately 12-fold more potent than thiourea and acetohydroxamic acid as references. Molecular docking analysis showed a good protein−ligand interaction profile against the urease target (PDBID: 4UBP), emphasizing the electronic and geometric effect of N,N-disubstituted thiourea. View Full-Tex

Synthesis of some benzimidazole derivatives endowed with 1,2,3-triazole as potential inhibitors of hepatitis C virus

New derivatives of 2-thiobenzimidazole incorporating triazole moiety were synthesized, characterized and tested in vitro for antiviral activity against hepatitis C virus (HCV) and hepatitis B virus (HBV). Their cytotoxicity was determined by the reduction in number of viable cells. All of the synthesized compounds are inactive against HBV and some showed activity against HCV. In particular, two compounds showed significant activity, 2-{4-[(1-benzoylbenzimidazol-2-ylthio)methyl]-1H-1,2,3-triazol-1-yl}-N-(p-nitrophenyl)-acetamide (13) and 2-(4-{[1-(p-chlorobenzoyl)-benzimidazol-2-ylthio)methyl]-1H-1,2,3-triazol-1-yl}-N-(p-nitrophenyl)-acetamide (17). The results give an insight into the importance of the substituent at position 2 of benzimidazole for the inhibition of HCV