Hydrothermal Synthesis of Zirconia Nanoparticles from Commercial Zirconia

AbstractRecently, it was observed that nanostructured zirconia (ZrO2) powder exhibits enhanced performance in many applications. In this study, a hydrothermal method was used for the synthesis of nano-crystalline ZrO2 powder from a fully monoclinic commercial zirconia. The products were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of SEM showed that after hydrothermal treatment under alkali condition, a different morphology from the commercial zirconia was obtained and XRD results showed that moreover to monoclinic phase (28%), cubic and tetragonal phases (72%) formed. According to TEM observations and XRD analysis, it was found that the nano-sized zirconia has an average particles size of 15-30nm

The effect of information systems on supply chain and performance of National Iranian South Oil Company (NISOC)

Accepting a kind of suitable strategies for supply chain achievement is one of the requirements of a manufacturing company.organizations to implement the different strategies of supply chain are required to use information systems.In this regard, this research respecting the different strategies of supply chain (lean and agile)and information systems strategies (efficiency and flexibility) attempt to examine the effect of these categories on supply chain performance and company.The methodology and the nature of this research is descriptive-survey. Sample population of this research is made up of nisoc’s managers and experts that are more than 2043 persons.By applying the cochrane’s formula,the sample population of this research determined as 231 persons that 222 questionaires completed and received. In this research, content validity and structure validity have been used and total questionnaire chronbach’s alfa is equal to 0/955 which indicates high level of reliability. because of measuring the effect of some dependent and indeppendent variables simultaneously, structure equations method (confirmation factor analysis) and pierson coefficient test have been used.Results indicate, in term of correational coefficient , that the effect of all variables over supply chain performance of company has been in a high level,but by applying the independent t correational test and pierson the main hypothesis and 3 sub hypotheses confirmed.Keywords: Information system strategy, lean supply chain, agile supply chain, supply chain performanc

On channel estimation and capacity for amplify and forward relay networks

Abstract-Relay networks have received considerable attention recently, especially when limited size and power resources impose constraints on the number of antennas within a wireless sensor network. In this paper, we design and analyze a training based linear mean square error (LMMSE) channel estimator for time division multiplex amplify-and-forward (AF) relay networks. For the purpose of performance comparison we consider three distinct cases; In the first scenario, each relay estimates its backward and forward channels, in the second scenario each relay knows its backward and forward channels perfectly and finally in the third scenario relays have no knowledge of channels. Finally, we find a lower bound for the capacity considering the effect of training and estimation error. I. INTRODUCTION Next generation wireless networks are demanding high data rate services to accommodate requests from various applications. In order to provide reliable communications, one needs to compensate for the effects of signal fading due to multipath propagation and strong shadowing. One way to address these issues is to transmit the signal through one or more relays In this paper, we extend current work by considering a training based LMMSE estimator for K relays in an AF configuration assuming a time division multiplex system such that the channel from relays to destination and vice versa are reciprocal. We derive a lower bound for the capacity of this relay network considering the effect of channel estimation error as part of noise at the destination. To contrast the results, we consider three cases; In the first scenario, each relay estimates its backward and forward channels, in the second scenario each relay knows its backward and forward channels perfectly, and finally in the third scenario relays do not know their backward and backward channels

Decays of metastable vacua in SQCD

The decay rates of metastable SQCD vacua in ISS-type models, both towards supersymmetric vacua as well as towards other nonsupersymmetric configurations arising in theories with elementary spectators, are estimated numerically in the semiclassical approximation by computing the corresponding multifield bounce configurations. The scaling of the bounce action with respect to the most relevant dimensionless couplings and ratios of scales is analyzed. In the case of the decays towards the susy vacua generated by nonperturbative effects, the results confirm previous analytical estimations of this scaling, obtained by assuming a triangular potential barrier. The decay rates towards susy vacua generated by R-symmetry breaking interactions turn out to be more than sufficiently suppressed for the phenomenologically relevant parameter range, and their behavior in this regime differs from analytic estimations valid for parametrically small scale ratios. It is also shown that in models with spectator fields, even though the decays towards vacua involving nonzero spectator VEVs don't have a strong parametric dependence on the scale ratios, the ISS vacuum can still be made long-lived in the presence of R-symmetry breaking interactions.Comment: 22 pages, 7 figure

Passive Dielectrophoretic Focusing of Particles and Cells in Ratchet Microchannels.

Focusing particles into a tight stream is critical for many microfluidic particle-handling devices such as flow cytometers and particle sorters. This work presents a fundamental study of the passive focusing of polystyrene particles in ratchet microchannels via direct current dielectrophoresis (DC DEP). We demonstrate using both experiments and simulation that particles achieve better focusing in a symmetric ratchet microchannel than in an asymmetric one, regardless of the particle movement direction in the latter. The particle focusing ratio, which is defined as the microchannel width over the particle stream width, is found to increase with an increase in particle size or electric field in the symmetric ratchet microchannel. Moreover, it exhibits an almost linear correlation with the number of ratchets, which can be explained by a theoretical formula that is obtained from a scaling analysis. In addition, we have demonstrated a DC dielectrophoretic focusing of yeast cells in the symmetric ratchet microchannel with minimal impact on the cell viability

Phenotypic and genetic diversity of motile aeromonads isolated from diseased fish and fish farms

Summary Samples from the kidney of 100 diseased fish with signs of haemorrhagic septicemia and 50 samples from outlet water of fish farms were taken aseptically and cultured. In the laboratory, 75 colonies of gram-negative bacteria were biochemically diagnosed as motile aeromonads in our Bacteriology Laboratory Unit using API 20E rapid identification system. The genotype identification using specific primers for 16S rDNA by PCR and direct sequencing of 28 Iranian motile aeromonads isolates were as follow: in diseased fish, Aeromonas hydrophila (3 isolates, 15%), A. veronii bv. sobria (8 isolates, 40%), A. bestiarum/piscicola (5 isolates, 25%), A. media (3 isolates, 15%), A. jandaei (1 isolate, 5%), A. aquariorum (0 isolate, 0%) and in water, Aeromonas hydrophila (0 isolate, 0%), A. veronii bv. sobria (6 isolates, 75%), A. bestiarum/piscicola (0 isolate, 0%), A. media (1 isolate, 12.5%), A. jandaei (0 isolate, 0%) and A. aquariorum (1 isolate, 12.5%). Results of this study suggest that the incidence of motile aeromonads septicemia due to A. veronii bv. sobria is the most prevalent motile aeromonads. Nucleotide polymorphisms on the sequencing results of the 16S rDNA were detected as noticeable inter and intra-specific variation within the population of different aeromonads isolates. In total, 10-20 variant nucleotide positions in this region were observed among Aeromonas spp

(Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry in the Effective Field Theory of Inflation

We apply the Effective Field Theory of Inflation to study the case where the continuous shift symmetry of the Goldstone boson \pi is softly broken to a discrete subgroup. This case includes and generalizes recently proposed String Theory inspired models of Inflation based on Axion Monodromy. The models we study have the property that the 2-point function oscillates as a function of the wavenumber, leading to oscillations in the CMB power spectrum. The non-linear realization of time diffeomorphisms induces some self-interactions for the Goldstone boson that lead to a peculiar non-Gaussianity whose shape oscillates as a function of the wavenumber. We find that in the regime of validity of the effective theory, the oscillatory signal contained in the n-point correlation functions, with n>2, is smaller than the one contained in the 2-point function, implying that the signature of oscillations, if ever detected, will be easier to find first in the 2-point function, and only then in the higher order correlation functions. Still the signal contained in higher-order correlation functions, that we study here in generality, could be detected at a subleading level, providing a very compelling consistency check for an approximate discrete shift symmetry being realized during inflation.Comment: v2 minor revisions; 39 pages, 5 figure

Assessing unmodified 70-mer oligonucleotide probe performance on glass-slide microarrays

BACKGROUND: Long oligonucleotide microarrays are potentially more cost- and management-efficient than cDNA microarrays, but there is little information on the relative performance of these two probe types. The feasibility of using unmodified oligonucleotides to accurately measure changes in gene expression is also unclear. RESULTS: Unmodified sense and antisense 70-mer oligonucleotides representing 75 known rat genes and 10 Arabidopsis control genes were synthesized, printed and UV cross-linked onto glass slides. Printed alongside were PCR-amplified cDNA clones corresponding to the same genes, enabling us to compare the two probe types simultaneously. Our study was designed to evaluate the mRNA profiles of heart and brain, along with Arabidopsis cRNA spiked into the labeling reaction at different relative copy number. Hybridization signal intensity did not correlate with probe type but depended on the extent of UV irradiation. To determine the effect of oligonucleotide concentration on hybridization signal, 70-mers were serially diluted. No significant change in gene-expression ratio or loss in hybridization signal was detected, even at the lowest concentration tested (6.25 μm). In many instances, signal intensity actually increased with decreasing concentration. The correlation coefficient between oligonucleotide and cDNA probes for identifying differentially expressed genes was 0.80, with an average coefficient of variation of 13.4%. Approximately 8% of the genes showed discordant results with the two probe types, and in each case the cDNA results were more accurate, as determined by real-time PCR. CONCLUSIONS: Microarrays of UV cross-linked unmodified oligonucleotides provided sensitive and specific measurements for most of the genes studied

Investigating the prevalence of sleep disorder and the impact of sweet almond on the quality of sleep in students of Tehran, Iran

Background: Insomnia is an important problem in medical sciences students and has implications for their educational progress. The current study aimed to estimate the prevalence of sleep disorders and investigating the impact of sweet almond on quality of sleep in students of the Tehran University of Medical Sciences (TUMS), Tehran, Iran who live in dormitories. Methods: This is a before-after study conducted in 2017. At first, using the ISI questionnaire prevalence of sleep disorders was determined. Sweet almond was the study intervention. Each day, 10 almonds were given to 446 students for 14 d. At the end of the second week, again ISI questionnaire was filled. SPSS was used to analyze data. The McNemar, Wilcoxson Signed Ranks, and Repeated Measures tests were used. Results: Out of 442 participants, 217 (49.1) were female. Before intervention, 343 (77.6) had insomnia and 99 (22.4) had normal sleep. After intervention, 306 (69.2) had insomnia and 136 (30.8) had normal sleep. Having sweet almond for two weeks is associated with reducing insomnia (P<0.05). Investigating the almond impact in different categories also showed that it has a reducing impact on severe, mild, weak and normal sleep categories (P<0.05). Conclusion: Sweet almond has impacts on quality of sleep of those students of the TUMS that are living in dormitories. Intervention programs to improve quality of sleep are necessary and with regard to the high prevalence of insomnia, students must be protected, guided and consulted. © 2019, Iranian Journal of Public Health. All rights reserved