Surface-modified alumina nanoparticles-filled aramid fiber-reinforced epoxy nanocomposites: preparation and mechanical properties

Iranian Polymer Journal - Surface of Al2O3 nanoparticles was modified with a silane coupling agent, and aramid fiber-reinforced epoxy nanocomposites were produced using these particles. Three...     

Algorithmic and software techniques for embedded vision on programmable processors

In the last few years, programmable architectures centered around high-end DSP processors have emerged as the platform of choice for high-volume embedded vision applications, such as automotive safety and video surveillance. Their programmability inherently addresses the problems presented by the sheer diversity of vision algorithms. This paper provides an overview of high-impact algorithmic and software techniques for embedded vision applications implemented on programmable architectures and discusses several system-level issues. We provide a general discussion and practical examples for the following categories of algorithmic techniques: fast algorithms, reduced dimensionality and mathematical shortcuts. Additionally, we discuss the importance of software techniques such as the use of fixed-point arithmetic, reduced data transfers and cache-friendly programming. In our experience, each of these techniques is a key enabler for real-time embedded vision systems.     

EVE: A Flexible SIMD Coprocessor for Embedded Vision Applications

In this paper we introduce EVE (embedded vision/vector engine), with a FlexSIMD (flexible SIMD) architecture highly optimized for embedded vision. We show how EVE can be used to meet the growing requirements of embedded vision applications in a power- and area-efficient manner. EVE’s SIMD features allow it to accelerate low-level vision functions (such as image filtering, color-space conversion, pyramids, and gradients). With added flexibility of data accesses, EVE can also be used to accelerate many mid-level vision tasks (such as connected components, integral image, histogram, and Hough transform). Our experiments with a silicon implementation of EVE show that it performs many low- and mid-level vision functions with a 3–12x speed advantage over a C64x+DSP, while consuming less power and area. EVE also achieves code size savings of 4–6x over a C64x+DSP for regular loops. Thanks to its flexibility and programmability, we were able to implement two end-to-end vision applications on EVE and achieve more than a 5× application-level speedup over a C64x+. Having EVE as a coprocessor next to a DSP or a general purpose processor, algorithm developers have an option to accelerate the low- and mid-level vision functions on EVE. This gives them more room to innovate and use the DSP for new, more complex, high-level vision algorithms.     

Fluorescent pseudomonads occurring in Macrotermes subhyalinus mound structures decrease Cd toxicity and improve its accumulation in sorghum plants

Cd-tolerant bacterial strains of fluorescent pseudomonads, mostly belonging to Pseudomonas monteillii, were isolated from termite mound soil (Macrotermes subhyalinus, a litter-forager and fungus-growing termite), in a Sudanese shrubby savanna, Burkina Faso. Such large mounds appeared as sites of great bacterial diversity and could be considered as hot spots of metal-tolerant fluorescent pseudomonads. Microbial isolates were inoculated to Sorghum plants (S. bicolor) in glasshouse experiments with soil amended with CdCl(2) (560 mg Cd kg(-1) soil). Microbial functional diversity was assessed at the end of the experiment by measurement of in situ patterns of catabolic potentials. All the bacteria isolates significantly improved the shoot and total biomass of sorghum plants compared to the control. Results concerning root biomass were not significant with some strains. Arbuscular mycorrhiza (AM) was greatly reduced by CdCl(2) amendment, and fluorescent pseudomonad inoculation significantly increased AM colonisation in the contaminated soil. The bacterial inoculation significantly improved Cd uptake by sorghum plants. Measurement of catabolic potentials on 16 substrates showed that the microbial communities were different according to the soil amendment. Soils samples inoculated with pseudomonad strains presented a higher use of ketoglutaric and hydroxybutiric acids, as opposed to fumaric acid in soil samples not inoculated. It is suggested that fluorescent pseudomonads could act indirectly in such metabolic processes by involving a lower rate of degradation of citric acid, in line with the effect of small organic acid on phytoextraction of heavy metals from soil. This is a first contribution to bioremediation of metal-contaminated sites with soil-to-plant transfer, using termite built structures. Further data are required on the efficiency of the bacterial strains isolated and on the processes involved.     

Modal analysis of multi-cracked beams with circular cross section

This paper proposes a numerical model that combines the finite element and component mode synthesis methods for the modal analysis of beams with circular cross section and containing multiple non-propagating open cracks. The model virtually divides a beam into a number of parts from the crack sections and couples them by flexibility matrices considering the interaction forces that are derived from the fracture mechanics theory. The main feature of the presented approach is that the natural frequencies and mode shapes of a beam with an arbitrary number of cracks and any kind of two end conditions can be conveniently determined with a reasonable computational time. Three numerical examples are given to investigate the effects of location and depth of cracks on the natural frequencies and mode shapes of the beams. Moreover, it is shown through these examples that the evaluation of modal data obtained by the proposed model gives valuable information about the location and size of defects in the beams.     

Adhesion of different bacterial strains to low-temperature plasma treated biomedical PVC catheter surfaces

OBJECTIVE: The precise nature of the differences between intrafamilial and extrafamilial child sexual abuse is not clear. The purpose of the present study is to provide clarification of these differences. METHOD: Archival data containing 1,037 cases of child sexual abuse were obtained from police files in two western Canadian cities with populations of about 180,000. Two trained research assistants coded and transcribed the data. RESULTS: Results showed: (1) earlier onset, longer duration, higher level of intrusion, and greater physical and emotional injury for intrafamilial victims; (2) less use of physical/verbal force, or enticements, and greater use of instructions "not to tell" by intrafamilial offenders; (3) more convictions and longer jail sentences for intrafamilial offenders; and (4) no intra-extrafamilial differences in victim sex preference. CONCLUSIONS: Boys are younger than girls at the time of first abuse in samples of criminal justice and hospital referrals, although only for older aged victims, for example, 8 to 17 years. Although statistically significant, there is little difference in level of intrusion perpetrated by intrafamilial and extrafamilial offenders, both are highly intrusive. Both intrafamilial and extrafamilial offenders use physical/verbal force, with older victims: extrafamilial offenders more often choose older victims, and therefore more often use force. Intrafamilial victims suffer greater physical and emotional injury, resulting from greater intrusion not duration of abuse. It's not clear that victim sex preferences of intra- and extrafamilial offenders exist.     

The Role of pH in the Mechanism of .OH Radical Induced Oxidation of Nicotine

The ^.OH radical induced oxidation of nicotine was studied using pulse radiolysis techniques from pH 1 to 13.6. Theoretical calculations were used to help interpret the experimental results. The bond dissociation enthalpies of all of the C H bonds of nicotine were determined using DFT calculations, coupled with the isodesmic reaction. From time-dependent density functional response theory, estimates were obtained of the location of the dominant transient absorption bands (λ_max), their intensities (electronic oscillator strength, f), and the electronic composition of these transitions. OH radicals as well as other potent oxidants reacted with free nicotine through separated, concerted electron proton transfer, leading mostly to the formation of an alpha-aminoalkyl radical located on the C_2′ carbon of the aliphatic ring ( A_2′ ). Protonated nicotine underwent hydrogen atom abstraction at the C_2′ and N_1′ positions, resulting in the formation of the conjugate acid of A_2′ ( A_2′H⁺ ) and the alkylamine radical cation ( N⁺ ), respectively. Doubly protonated nicotine underwent the same reaction pathways, leading to two corresponding conjugate acid species, protonated at the aromatic nitrogen position: PyrH⁺A_2′H⁺ and PyrH⁺N⁺ _. All these radicals interconverted between each other through hydrolytic reactions. The radical A_2′ and its conjugate acid PyrH⁺A_2′ absorbed 10 times stronger than the N⁺ species, based on calculations of f. From the growth of the transient absorption of A_2′ (λ_max=330 nm, ε=8080 M ⁻¹ cm⁻¹), second-order rate constants were determined: k_(OH+Nic)=6.7×10⁹ M ⁻¹ s ⁻¹, k_(OH+NicH)=1.0×10⁹ M ⁻¹ s⁻¹. The alpha-aminoalkyl radicals decayed by disproportionation to form iminium cations 1 – 5 , which contributed to an increase in the specific conductivity of the basic solutions of nicotine following electron pulse irradiation.     

Application of inverse analysis to determine the strain distribution with optoelectronic method insensitive to temperature changes

This paper presents the application of inverse analysis to determine the stress distribution in a way that is insensitive to changes in temperature. For this purpose, a sensor with a fiber Bragg grating (FBG) was used. The paper discusses the direct solution of the task and presents the development and validation of a mathematical model of the Bragg grating sensor. Computer simulations were performed to apply numerical algorithms that completed the calculations according to the mathematical structure of the model and considered the values of all other elements of the FBG sensor. An experimental study was also conducted using a constructed measuring post.