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1.
Materials (Basel) ; 15(19)2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36234310

RESUMO

The safety and economy of an infrastructure project depends on the material and design equations used to simulate the performance of a particular member. A variety of materials can be used in conjunction to achieve a composite action, such as a hollow steel section filled with concrete, which can be successfully utilized in the form of an axially loaded member. This study aims to model the ultimate compressive strength (Pu) of concrete-filled hollow steel sections (CFSS) by formulating a mathematical expression using gene expression programming (GEP). A total of 149 datapoints were obtained from the literature, considering ten input parameters, including the outer diameter of steel tube (D), wall thickness of steel tube, compressive strength of concrete (fc'), elastic modulus of concrete (Ec), yield strength of steel (fv), elastic modulus of steel (Es), length of the column (L), confinement factor (ζ), ratio of D to thickness of column, and the ratio of length to D of column. The performance of the developed models was assessed using coefficient of regression R2, root mean squared error RMSE, mean absolute error MAE and comparison of regression slopes. It was found that the optimal GEP Model T3, having number of chromosomes Nc = 100, head size Hs = 8 and number of genes Ng = 3, outperformed all the other models. For this particular model, R2overall equaled 0.99, RMSE values were 133.4 and 162.2, and MAE = 92.4 and 108.7, for training (TR) and testing (TS) phases, respectively. Similarly, the comparison of regression slopes analysis revealed that the Model T3 exhibited the highest R2 of 0.99 with m = 1, in both the TR and TS stages, respectively. Finally, parametric analysis showed that the Pu of composite steel columns increased linearly with the value of D, t and fy.

2.
Ecotoxicol Environ Saf ; 226: 112853, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34619475

RESUMO

Climate change and the consequent alteration in agricultural circumstances enhance the susceptibility of fresh water use particularly in water-scarce regions. Marginal quality water reuse is a common alternative practice but possible perils of metal accretion in plant parts are mostly ignored. The present research aimed to probe the impact of treated wastewater (TWW) and untreated wastewater (UTWW) on metal accumulation in flower petals and their influence on essential oil contents of fragrant Rosa species (R. Gruss-an-teplitz, R. bourboniana, R. centifolia, R. damascena) in a peri-urban area of Faisalabad, Pakistan during January, 2017 to December, 2018. The mineral and chemical contents in canal water (CW) and TWW were less than recommended levels of national environmental quality standards (NEQS) for wastewater of Pakistan. The experimentally UTWW possessed higher electrical conductivity (EC), biological and chemical oxygen demand (BOD and COD), and some metals (Pb, Co, Cr) that were above the permissible levels. The experimental data revealed that except Cr other metals contents in the flower petals were less than the WHO recommended limits (for medicinal plants) under experimental irrigation regimes. Rosa centifolia and R. damascena possessed higher metal i.e. Zn, Cu, Pb, Cr, Co contents while Fe and Ni contents were higher in R. Gruss-an-Teplitz and R. bourboniana respectively. There were twelve constituents which were detected in essential oil by gas chromatography. Major constituents were phenyl ethyl alcohol, citronellol, geranyl acetate, γ- undelactone, methyl eugenol, and limonene whose share was 48.17%, 41.11%, 8.46%, 4.82%, 4.44%, and 4.15% respectively whereas concentrations of other 06 constituents were less than 3.7%. Phenyl ethyl alcohol, lion shared constituent of essential oil was found highest (48.17%) in R. Gruss-an-Teplitz whereas minimum level was recorded in R. damascena (28.84%) under CW. In contrast, citronellol (chief component of fragrance) was highest in R. damascena (41.11%) in UTWW while the lowest level was found in R. Gruss-an-Teplitz (17.41%) in CW. This study confirmed the variations in metal concentrations of Rosa species due to different absorbability of each metal in flower petals. It also indicates that wastewater did not affect the composition but there were quantitative differences in aroma constituents and chemical composition of essential oil.


Assuntos
Metais Pesados , Óleos Voláteis , Rosa , Monitoramento Ambiental , Flores/química , Metais Pesados/análise , Águas Residuárias/análise , Água
3.
Saudi J Biol Sci ; 28(1): 1-9, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33424277

RESUMO

Root-knot nematodes Meloidogyne incognita (Kofoid and White) Chitwood and Rhizoctonia bataticola (Taub.) Butler, fungus, are very dangerous root damaging pathogens. Present study was planned to establish a chemical control of these root deteriorating pathogens under lab conditions as well as in field. Maximum death rate of nematode juveniles and minimum numbers of nematode eggs hatched were recorded in plates treated with Cadusafos (Rugby® 100G) @12 g/100 ml and Cartap® (4% G) @9g/100 ml. Chemical treatment of Rhizoctonia bataticola with Trifloxystrobin + Tebuconazole (Nativo®) @0.2 g/100 ml and Mancozeb + Matalaxyl (Axiom) @0.25 g/100 ml significantly controlled the mycelial growth in plates. The best treatments tested in laboratory were applied in field as protective and curative treatments. Results proved that chemical control of root-knot nematode and root rot fungi by tested chemicals at recommended time and dose is a significant management technique under field conditions.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32603923

RESUMO

Organophosphate, carbamate and pyrethroid pesticides are the most common insecticides used worldwide. They may cause chronic poisoning in farmers and acute poisoning in homicidal or suicidal cases. The determination of trace levels of these pesticides in human blood and urine is very challenging. This study focuses on a simultaneous quantitation method that was developed and validated for multi-class nine pesticides belonging to organophosphate, carbamate and pyrethroid classes in human blood and urine. Target pesticides were extracted from blood and urine using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction method. Capillary column DB-35 ms (15 m × 0.25 mm, 0.25 µm) was used for chromatography with a 0.079 ml/min flow rate of carrier gas at constant pressure mode. Quantitation of sulfotep, phorate, carbofuran, chlorpyriphos, profenophos, triazophos, pyriproxyfen, lambda-cyhalothrin and permethrin was performed by mass spectrometer equipped with electron impact ionization source using selected ion monitoring (SIM) mode. The lower and upper limits of quantitation for all nine pesticides were 0.01 mg/L and 2.0 mg/dL respectively. The proposed method was proved to be simple, fast, sensitive, and robust. It has been applied to the analysis of 9 pesticides samples.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos de Praguicidas/sangue , Resíduos de Praguicidas/urina , Conteúdo Gastrointestinal/química , Humanos , Limite de Detecção , Modelos Lineares , Extração Líquido-Líquido/métodos , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Praguicidas/análise , Praguicidas/intoxicação , Reprodutibilidade dos Testes
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