Effect of tow-drop gaps on the damage resistance and tolerance of Variable-Stiffness Panels

This paper presents an experimental study of the effects of tow-drop gaps in Variable Stiffness Panels under drop-weight impact events. Two different configurations, with and without ply-staggering, have been manufactured by Automated Fibre Placement and compared with their baseline counterpart without defects. For the study of damage resistance, three levels of low velocity impact energy are generated with a drop-weight tower. The damage area is analysed by means of ultrasonic inspection. Results of the analysed defect configurations indicate that the influence of gap defects is only relevant under small impact energy values. However, in the case of damage tolerance, the residual compressive strength after impact does not present significant differences to that of conventional straight fibre laminates. This indicates that the strength reduction is driven mainly by the damage caused by the impact event rather than by the influence of manufacturing-induced defects

Variable-stiffness composite panels: Defect tolerance under in-plane tensile loading

Automated Fiber Placement is being extensively used in the production of major composite components for the aircraft industry. This technology enables the production of tow-steered panels, which have been proven to greatly improve the structural efficiency of composites by means of in-plane stiffness variation and load redistribution. However, traditional straight-fiber architectures are still preferred. One of the reasons behind this is related to the uncertainties, as a result of process-induced defects, in the mechanical performance of the laminates. This experimental work investigates the effect of the fiber angle discontinuities between different tow courses in a ply on the un-notched and open-hole tensile strength of the laminate. The influence of several manufacturing parameters are studied in detail. The results reveal that 'ply staggering' and '0% gap coverage' is an effective combination in reducing the influence of defects in these laminates

The Andean Biotic Index (ABI): revised tolerance to pollution values for macroinvertebrate families and index performance evaluation.

Score-based biotic indices are widely used to evaluate the water quality of streams and rivers. Few adaptations of these indices have been done for South America because there is a lack of knowledge on mac-roinvertebrate taxonomy, distribution and tolerance to pollution in the region. Several areas in the Andes are densely populated and there is need for methods to assess the impact of increasing human pressures on aquatic ecosystems. Considering the unique ecological and geographical features of the Andes, macroinvertebrate indices used in other regions must be adapted with caution. Here we present a review of the literature on mac-roinvertebrate distribution and tolerance to pollution in Andean areas above 2 000masl. Using these data, we propose an Andean Biotic Index (ABI), which is based on the BMWP index. In general, ABI includes fewer macroinvertebrate families than in other regions of the world where the BMWP index has been applied because altitude restricts the distribution of several families. Our review shows that in the high Andes, the tolerance of several macroinvertebrate families to pollution differs from those reported in other areas. We tested the ABI index in two basins in Ecuador and Peru, and compared it to other BMWP adaptations using the reference condi-tion approach. The ABI index is extremely useful for detecting the general impairment of rivers but class quality boundaries should be defined independently for each basin because reference conditions may be different. The ABI is widely used in Ecuador and Peru, with high correlations with land-use pressures in several studies. The ABI index is an integral part of the new multimetric index designed for high Andean streams (IMEERA). Rev. Biol. Trop. 62 (Suppl. 2): 249-273. Epub 2014 April 01.

Nanoparticle-coated organic-inorganic microparticles: experimental design and gastrointestinal tolerance evaluation

The influences of the spray-drying parameters and the type of nanoparticles (nanocapsules or nanospheres) on the characteristics of nanoparticle-coated diclofenac-loaded microparticles were investigated by using a factorial design 3². Gastrointestinal tolerance following oral administration in rats was evaluated. Formulations were selected considering the best yields, the best encapsulation efficiencies and the lowest water contents, presenting surfaces completely coated by nanostructures and a decrease in the surface areas in relation to the uncoated core. In vitro drug release demonstrated the influence of the nanoparticle-coating on the dissolution profiles of diclofenac. Nanocapsule-coated microparticles presented a protective effect on the gastrointestinal mucosa.

Inorganic Nanoparticles and the Immune System: Detection, Selective Activation and Tolerance

The immune system is the responsible for body integrity and prevention of external invasion. On one side, nanoparticles are no triggers that the immune system is prepared to detect, on the other side it is known that foreign bodies, not only bacteria, viruses and parasites, but also inorganic matter, can cause various pathologies such as silicosis, asbestosis or inflammatory reactions. Therefore, nanoparticles entering the body, after interaction with proteins, will be either recognized as self-agents or detected by the immune system, encompassing immunostimulation or immunosuppression responses. The nature of these interactions seems to be dictated not specially by the composition of the material but by modifications of NP coating (composition, surface charge and structure). Herein, we explore the use of gold nanoparticles as substrates to carry multifunctional ligands to manipulate the immune system in a controlled manner, from undetection to immunostimulation. Murine bone marrow macrophages can be activated with artificial nanometric objects consisting of a gold nanoparticle functionalized with peptides. In the presence of some conjugates, macrophage proliferation was stopped and pro-inflammatory cytokines were induced. The biochemical type of response depended on the type of conjugated peptide and was correlated with the degree of ordering in the peptide coating. These findings help to illustrate the basic requirements involved in medical NP conjugate design to either activate the immune system or hide from it, in order to reach their targets before being removed by phagocytes. Additionally, it opens up the possibility to modulate the immune response in order to suppress unwanted responses resulting from autoimmunity, or allergy or to stimulate protective responses against pathogens.

On Fault Tolerance Methods for Networks-on-Chip

Technology scaling has proceeded into dimensions in which the reliability of manufactured devices is becoming endangered. The reliability decrease is a consequence of physical limitations, relative increase of variations, and decreasing noise margins, among others. A promising solution for bringing the reliability of circuits back to a desired level is the use of design methods which introduce tolerance against possible faults in an integrated circuit. This thesis studies and presents fault tolerance methods for network-onchip (NoC) which is a design paradigm targeted for very large systems-onchip. In a NoC resources, such as processors and memories, are connected to a communication network; comparable to the Internet. Fault tolerance in such a system can be achieved at many abstraction levels. The thesis studies the origin of faults in modern technologies and explains the classification to transient, intermittent and permanent faults. A survey of fault tolerance methods is presented to demonstrate the diversity of available methods. Networks-on-chip are approached by exploring their main design choices: the selection of a topology, routing protocol, and flow control method. Fault tolerance methods for NoCs are studied at different layers of the OSI reference model. The data link layer provides a reliable communication link over a physical channel. Error control coding is an efficient fault tolerance method especially against transient faults at this abstraction level. Error control coding methods suitable for on-chip communication are studied and their implementations presented. Error control coding loses its effectiveness in the presence of intermittent and permanent faults. Therefore, other solutions against them are presented. The introduction of spare wires and split transmissions are shown to provide good tolerance against intermittent and permanent errors and their combination to error control coding is illustrated. At the network layer positioned above the data link layer, fault tolerance can be achieved with the design of fault tolerant network topologies and routing algorithms. Both of these approaches are presented in the thesis together with realizations in the both categories. The thesis concludes that an optimal fault tolerance solution contains carefully co-designed elements from different abstraction levels

Pisolithus sp. tolerance to glyphosate and isoxaflutole in vitro

The ectomycorrhizal fungi have different tolerance to herbicides and may promote the survival and growth of the eucalypts tree. This study aimed to evaluate the tolerance of Pisolithus sp. isolates to glyphosate and isoxaflutole. The isolates evaluated were D3, D16, D17, Pt24 and UFVJM04. Glyphosate concentrations were: 0, 32, 63, 127 and 254 mg L-1 in liquid medium; 0, 32, 63, 127, 254, 507 and 1014 mg L-1 in solid medium. For isoxaflutole, the concentrations were 0, 295, 589, 1178 and 2355 mg L-1 for both media. Assays were independent for each herbicide and culture medium. The tolerance of isolates depended on the herbicide and its concentration in each type of culture medium. Pt24 was the most tolerant to glyphosate and the UFVJM04 to isoxaflutole. Glyphosate was more toxic to isolates of Pisolithus than isoxaflutole.

Initial growth of Bauhinia variegata trees under different colored shade nets and light conditions

Bauhinia variegata and B. variegata var. candida, commonly known as orchid trees, are small sized trees widely used for urban forestry and landscaping. Adult plants grow under full sun; in Brazil, however, seedlings are generally cultivated in commercial nurseries under natural half-shading. The objective of this study was to evaluate the influence of different colored shade nets and light conditions on the initial growth of B. variegata and B. variegata var. candida. The influence of six light conditions (red net with 50% shading; blue net with 50% shading; black net with 70% shading; black net with 50% shading; black net with 30% shading; and full sun) on the initial growth of B. variegata and B. variegata var. candida were evaluated along 160 days, and growth relationships were calculated. Seedlings showed more efficiency on the use of photoassimilated compounds when grown under full sun. Such condition is the most appropriate for seedling production of B. variegata and B. variegata var. candida, contradicting what has been performed in practice.

Water consumption when exposed to sun and shade for native goats in the semiarid of the State of Paraiba, Brazil

This work aimed to evaluate the preference and water consumption of native goats in the semiarid of Brazil. The water was freely supplied, in individual buckets, one exposed to the sun and the other in the shade. The experiment was realized using 18 animals of Moxotó, Graúna and Azul breeds, with average weight of 16,6 ± 2,4 kg, kept in confinement in individual stalls equipped with feeders and drinkers, during the period from January to February of 2009. The water temperature was measured by sensors (thermocouples type T - copper/constantan), which were coupled to a system of data acquisition. It was observed that the average water temperature exposed to the sun was 29.02 ºC, and 23.85 ºC in the shade. For all breeds there was a preference for the water exposed to the sun, corresponding to an average consumption of 64.71% of the total. Among the breeds, the greatest preference for water exposed to the sun was the Azul (71.18%), followed by the Moxotó (65.95%) and the Graúna (57.00%). The animals consumed more water during the day, and the average water consumption was 1.15 grams day-1, corresponding to 6.9 % of body weight of the animals.

Growth, biomass allocation and photosynthesis of Rolandra fruticosa (asteraceae) in response to shade

The effects of shade on growth, biomass allocation patterns and photosynthetic response was examined for Rolandra fruticosa (L.) Kuntze, a common perennial weed shrub in cultivated pastures and agricultural areas of Brazilian Amazonia, for plants grown in full sunlight and those shaded to 30 % of full sunlight over a 34-d period. Specific leaf area and leaf area ratio were higher for shade plants during all the experimental period. Shade plants allocated significantly less biomass to root tissue than sun plants and relative growth rate was higher in sun plants. Sun leaves had significantly higher dark respiration and light saturated rates of photosynthesis than shade leaves. The apparent quantum efficiency was higher for shade leaves, while light compensation point was higher for sun leaves. These results are discussed in relation to their ecological and weed management implications.

Tolerance of eucalypt (Eucalyptus spp.) seedlings to imazapyr in nutritive solution

Imazapyr has presented excellent results in controlling coppices in stand reforms of eucalypt forests, despite differences in the efficacy levels. To find out whether these different responses are caused by the genetic variability of the cultivated materials, two experiments were carried out under greenhouse conditions with different imazapyr doses in a hydroponic system in plastic vases containing 2,500 mL solution. The clones IEF-1 (Eucalyptus grandis x Eucalyptus sp. hybrid), GE 463 (E. urophylla x E. grandis), and MN 445 (E. grandis x Eucalyptus sp. hybrid) were used in the first assay, and IEF-1, IEF2 (E. grandis x E. urophylla) x Eucalyptus sp. hybrid) and the clones 129 and 7182 (E. grandis x Eucalyptus sp. hybrids) in the second assay. Thirty days after transplanting the seedlings to a nutritive solution, imazapyr was applied to the solution at doses of 0.00, 0.05, 0.10, 0.20, 0.40, 0.80, 1.60 and 3.20 muL L-1. Clone GE 463 proved to be more tolerant to imazapyr than clones IEF-1 and MN 445 in the first assay; however, in the second, clone 7182 was the most tolerant. Thus, doses should also be differentiated when controlling coppices, according to the cultivated clone.

Tolerance of sugarcane cultivars to chemical eradication

Knowledge of the minimum rate of glyphosate required to eradicate sugarcane ratoons can reduce the amount of herbicide used. To confirm this hypothesis, this study aimed to investigate the tolerance of different sugarcane cultivars to chemical eradication, at different glyphosate rates. The experiment was conducted in a randomized block design in a split-plot scheme, with four replications. The sugarcane cultivars (IACSP94-2094, IACSP94-2101, IACSP93-3046, IACSP94‑4004, IAC86-2480, and RB72454) were allocated in plots and the glyphosate rates (0, 1,440, 2,160, 2,880, 3,600, and 4,320 g ha-1), in the sub plots. The traits evaluated were signs of poisoning symptoms; total chlorophyll content, plant height, percentage of dead tillers, and dry weight of the plants. At 45 days after application (DAA), the glyphosate rate of 1,440 g a.e. ha-1 eradicated the cultivars IACSP94-2094 and IACSP94-2101, as well as RB72454 with application of 2,160 g a.e. ha‑1. Application of glyphosate 2,880 g a.e. ha-1 eradicated both IACSP93-3046 and IAC86-2480 and glyphosate 3,600 g a.e. ha-1 eradicated IACSP94-4004. The most tolerant cultivar was IACSP94‑4004, eradicated at the rate of 3,600 g. a.e. ha-1. This confirms the hypothesis that knowing the cultivar's tolerance leads, in practice, to a smaller amount of herbicide applied to the environment, which also reduces production costs.

Effect of plant density and seed position on mother plant on physiological characteristic of cocklebur (Xanthium strumarium) seeds

Experiments were conducted in 2010 to determine the influence of plant density and seed position on the mother plant on seed physiological characteristics of cocklebur (Xanthium strumarium). Cocklebur burs were collected in fall of 2010 from Research Farm of University of Agricultural Sciences and Natural Resources of Gorgan, Iran. The experiment was established as factorial arrangement using a completely randomized design with three replications. The factors included different densities of cocklebur (0, 2, 4, 6 and 8 plant m-2) and the top and bottom parts of the canopy. Non dormant seeds were used for determining cardinal temperatures and tolerance to salinity and drought stresses. Base, optimum and ceiling germination temperatures were estimated between 7.09 to 12.33, 32 to 35 and 44 to 45 respectively in different treatments. Salinity stress up to 300 Mm and osmotic potential 8 bar inhibited the germination completely. Comparison of base temperatures and sigmoid equation coefficients showed that seeds produced in the top had higher germination than those that produced at the bottom of the mother plant. It seems plant densities through seed position on the mother plant affect seed quality. Likewise changes of light quality and quantity in shade environment increased seed dormancy in matured seeds. Shade environment affect seed germination on mother plant that increased dormancy of seeds maturing under shade be an adaptive response that reduces the probability of germination of offspring under unfavorable (shade, competitive) conditions.

Sugarcane tolerance to ratoon eradication with glyphosate determined by physiological responses

This study aimed to evaluate the tolerance of sugarcane cultivars to ratoon eradication under different glyphosate rates by means of physiological responses. Therefore, a trial was carried out in randomized complete blocks with 4 x 4 factorial design (cultivars x rates) totaling 16 treatments with four replicates. The cultivars IAC91-5155, IACSP93-3046, and IAC86-2480 and IAC87-3396 and the glyphosate rates 0 g ha-1; 1,920 g ha-1; 2,400 g ha-1; 2,880 g ha-1 were tested. The variables analyzed were percentage of tiller mortality, quantum efficiency of PSII (Fv/Fm) and SPAD index. The results showed that there are differences among sugarcane cultivars for tiller eradication and for physiological responses with glyphosate different rates. The rate of 2,880 g ha-1 was the most efficient in eliminating sugarcane tillers. The cultivars IAC86-2480, IAC87-3396 and IACSP93-3046 were the most sensitive and the IAC91-5155 tolerated, for a longer period of time, the damage to the photosynthetic apparatus of the ratoons caused by glyphosate desiccation. Due to different responses, different managements should be considered for eliminating ratoons of different cultivars.