Several studies have reported the adverse effects of recalcitrant compounds and emerging contaminants present in industrial effluents, which are not degradable by ordinary biological treatment. Many ...of these compounds are likely to accumulate in living organisms through the lipid layer. At concentrations above the limits of biological tolerance, these compounds can be harmful to the ecosystem and may even reach humans through food chain biomagnification. In this regard, advanced oxidation processes (AOPs) represent an effective alternative for the removal of the pollutants. This study focused on the AOP involving the use of ultraviolet radiation in homogeneous and heterogeneous systems. Based on the literature review, comparisons between natural and artificial light were established, approaching photoreactors constructive and operational characteristics. We concluded that the high availability of solar power in Brazil would make the implementation of the AOP using natural solar radiation for the decontamination of effluents feasible, thereby contributing to clean production and biodiversity conservation. This will serve as an important tool for the enforcement of environmental responsibility among public and private institutions.
In this note, we present a new continuous control mechanism that compensates for uncertainty in a class of high-order, multiple-input-multiple-output nonlinear systems. The control strategy is based ...on limited assumptions on the structure of the system nonlinearities. A new Lyapunov-based stability argument is employed to prove semiglobal asymptotic tracking.
Chagas disease is caused by the protozoan Trypanosoma cruzi, affecting around 8 million people worldwide. After host cell invasion, the infective trypomastigote form remains 2-4 hours inside acidic ...phagolysosomes to differentiate into replicative amastigote form. In vitro acidic-pH-induced axenic amastigogenesis was used here to study this step of the parasite life cycle. After three hours of trypomastigote incubation in amastigogenesis promoting acidic medium (pH 5.0) or control physiological pH (7.4) medium samples were subjected to three rounds of centrifugation followed by ultrafiltration of the supernatants. The resulting exoproteome samples were trypsin digested and analysed by nano flow liquid chromatography coupled to tandem mass spectrometry. Computational protein identification searches yielded 271 and 483 protein groups in the exoproteome at pH 7.4 and pH 5.0, respectively, with 180 common proteins between both conditions. The total amount and diversity of proteins released by parasites almost doubled upon acidic incubation compared to control. Overall, 76.5% of proteins were predicted to be secreted by classical or non-classical pathways and 35.1% of these proteins have predicted transmembrane domains. Classical secretory pathway analysis showed an increased number of mucins and mucin-associated surface proteins after acidic incubation. However, the number of released trans-sialidases and surface GP63 peptidases was higher at pH 7.4. Trans-sialidases and mucins are anchored to the membrane and exhibit an enzyme-substrate relationship. In general, mucins are glycoproteins with immunomodulatory functions in Chagas disease, present mainly in the epimastigote and trypomastigote surfaces and could be enzymatically cleaved and released in the phagolysosome during amastigogenesis. Moreover, evidence for flagella discard during amastigogenesis are addressed. This study provides the first comparative analysis of the exoproteome during amastigogenesis, and the presented data evidence the dynamism of its profile in response to acidic pH-induced differentiation.
A sufficiently smooth projection operator Cai, Z.; de Queiroz, M.S.; Dawson, D.M.
IEEE transactions on automatic control,
2006-Jan., 2006, 2006-01-00, 20060101, Letnik:
51, Številka:
1
Journal Article
Recenzirano
In this note, we introduce a new parameter projection operator for adaptation laws. The projection operator replaces the common Lipschitz continuity property with the stronger property of arbitrarily ...many times continuous differentiability. The proposed projection is useful for backstepping-based, robust adaptive controllers which require multiple differentiations of the adaptation law.
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•Heat recovery and power generation in SCWO flame and flameless regime.•Thermal and transport properties of mixtures at supercritical water state.•Hydrothermal flame oxidation ...kinetics.•Hydrothermal flame behavior and characteristics.•Modeling of SCWO.
Supercritical water oxidation (SCWO) has the potential to be considered a clean energy generation process, as the process effluent is a high temperature, high pressure stream with a high enthalpy content that can be converted to heat and shaft work. In this work the state of the art of SCWO has been reviewed, focusing on energy production. For the description of thermodynamic and transport properties, there are some methods recommended for pure substances, but the applicability of those methods for mixtures at supercritical state is yet not clear. Most of the work found in literature use cubic equations of state and linear mixing rules. The design of reactors has evolved in order to reduce the drawbacks of corrosion and salt deposition, in general, through the dilution of reaction products. In order to make the process profitable energetically different strategies must be used to keep the products at the highest temperature without compromising the safety, and the hydrothermal flames if correctly stabilized are a good choice. Reactors and reaction systems able to process feeds consisting of suspension with high inorganic contents without diluting the effluent reducing its temperature must be developed. On the other hand, the systems of energy recovery must be improved, especially the expanders, in order to recover the pressure work as well as the thermal energy. Modeling tools can help in both aspects. But for developing good models a good comprehension of thermal and transport properties of mixtures at supercritical state, as well as oxidation kinetics under that condition are essential data that must be further investigated in order to find energetically efficient processes.
Abstract
Stable isotopes are useful for estimating livestock diet selection. The objective was to compare δ
13
C and δ
15
N to estimate diet proportion of C
3
–C
4
forages when steers (
Bos
spp.) ...were fed quantities of rhizoma peanut (
Arachis
glabrata
; RP; C
3
) and bahiagrass (
Paspalum
notatum
; C
4
).Treatments were proportions of RP with bahiagrass hay: 100% bahiagrass (0%RP); 25% RP + 75% bahiagrass (25%RP); 50% RP + 50% bahiagrass (50%RP); 75% RP + 25% bahiagrass (75%RP); and 100% RP (100% RP). Feces, plasma, red blood cell (RBC), and hair were collected at 8-days intervals, for 32 days. Two-pool mixing model was utilized to back-calculate the proportion of RP based on the sample and forage δ
13
C or δ
15
N. Feces showed changes using δ
13
C by 8 days, and adj. R
2
between predicted and observed RP proportion was 0.81 by 8 days. Plasma, hair, and RBC required beyond 32-days to reach equilibrium, therefore were not useful predictors of diet composition during the study. Diets were best represented using fecal δ
13
C at both 8-days and 32-days. By 32-days, fecal δ
15
N showed promise (R
2
= 0.71) for predicting diet composition in C
3
–C
4
diets. Further studies are warranted to further corroborate fecal δ
15
N as a predictor of diet composition in cattle.
This paper presents a study on the mechanical characterization of novel short curauá/glass fibre reinforced interlaminar hybrid composite adhesive joints. The study aims to optimize the performance ...of these joints by analysing their mechanical properties as a function of the number of external synthetic layers and the architectural symmetry. Short curauá fibres and glass fibre bidirectional fabrics were used with a bi-component epoxy matrix in order to fabricate the hybrid composite adherends. The glass fibre bidirectional fabrics were placed on the outer layers, while the short curauá fibres were used as the core of the hybrid composites. The mechanical properties of the composites used as adherends, including tensile strength, flexural strength, and impact resistance, were determined through mechanical testing. Single lap joints bonded with a structural ductile bi-component epoxy automotive adhesive were fabricated and tested for each case. The results show that the failure mode of the bonded joints is strongly influenced by the composition and configuration of the adherends' composite layers. It was found that the effect of the number of synthetic layers is highly significant for bonded joint failure load, while no significant variation was observed as a function of architecture symmetry. This study provides valuable insights into the mechanical properties of adhesively bonded joints in hybrid curauá/glass fibre reinforced composites, which can be useful in the design and optimization of these materials for various engineering applications.
Roots and rhizomes can play an important role in nutrient cycling, however, few studies have investigated how their decomposition pattern is affected by defoliation and time of the year. This 2-year ...study evaluated root-rhizome composition and decomposition of a warm-season rhizomatous perennial legume rhizoma peanut (RP; Arachis glabrata Benth.) under continuous stocking or when defoliated by clipping every 56 days. A 168-days incubation trial was performed to determine disappearance of biomass and N and changes in acid detergent fiber (ADF), acid detergent insoluble N (ADIN), and C:N ratio. Additionally, three 56-days incubations were performed each year to evaluate the disappearance coefficient (B
) and relative decay rate (k). There were no treatment differences in any response for the 168-days incubation. After 168 days, 21 and 60% of initial biomass and initial N remained, respectively. Relative decay rate for OM and N were 0.0088 and 0.0035 g g
day
, respectively. Carbon-to-N ratio decreased from 29 at day 0 to 17 at day 168. Concentration of ADIN increased from 6.9 to 19.3 g kg
, plateauing at day 79. The B
and k for remaining OM and N were greater in late than early season and could be explained by greater N concentration and lesser C:N ratio. Rapid decomposition, difference in C:N ratio from day 0 to 168, and the increase in ADIN concentration during incubation indicate large amounts of root-rhizome-soluble C at initiation of incubation. These data indicate that RP root-rhizome turnover is more responsive to season than defoliation frequency.
This study evaluated the role of dung beetle species alone or associated under different species on nitrous oxide (N
O) emission, ammonia volatilization, and the performance of pearl millet ...Pennisetum glaucum (L.). There were seven treatments, including two controls (soil and soil + dung without beetles), single species of Onthophagus taurus Shreber, 1759 (1), Digitonthophagus gazella Fabricius, 1787 (2), or Phanaeus vindex MacLeay, 1819 (3); and their assemblages (1 + 2 and 1 + 2 + 3). Nitrous oxide emission was estimated for 24 days, when pearl millet was planted in sequence to assess growth, nitrogen yield (NY), and dung beetle activity. Dung beetle species presented greater N
O flow of dung on the 6th day (80 g N
O-N ha
day
) compared to soil and dung (2.6 g N
O-N ha
day
). Ammonia emissions varied with the presence of dung beetles (P < 0.05), and D. gazella had less NH
N on days 1, 6, and 12 with averages of 2061, 1526, and 1048 g ha
day
, respectively. The soil N content increased with dung + beetle application. Dung application affected pearl millet herbage accumulation (HA) regardless of dung beetle presence, and averages ranged from 5 to 8 g DM bucket
. A PCA analysis was applied to analyze variation and correlation to each variable, but it indicated a low principal component explanation (less than 80%), not enough to explain the variation in findings. Despite the greater dung removal, the largest species, P. vindex and their species combination, need to be more studied to get a better understanding about their contribution on greenhouse gases. The presence of dung beetles prior to planting improved pearl millet production by enhancing N cycling, although assemblages with the three beetle species enhanced N losses to the environment via denitrification.
The application of adhesively bonded joints in automotive industry has increased significantly in recent years mainly because of the potential for lighter weight vehicles, fuel savings and reduced ...emissions. The use of composites in making automotive body components to achieve a reduced vehicle mass has also continuously increased. Natural fibre composites have recently attracted a great deal of attention by the automotive industry due to their many attractive benefits (e.g. high strength-to-weight ratio, sustainable characteristics and low cost). However, the literature on natural fibre-reinforced polymer composite adhesive joints is scarce and needs further investigation. The main objective of this study was to evaluate and compare the mechanical performance of adhesively bonded joints made of synthetic- and natural fibre-reinforced polymer composites. Similar and dissimilar single lap joints bonded with a modern tough structural adhesive used in the automotive industry, as well as the epoxy resin AR260 (the same resin used in composite fabrication) were tested. It was found that the average failure loads varied significantly with adhesive material strength and adherend stiffness. Furthermore, it was also observed that failure mode has a significant effect in failure load. The jute-based natural fibre composites joints, both hybrid and purely natural, were superior in strength compared to the sisal-based natural composites joints.
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