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Number of results: 2870
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Abstract

Point of present exploration was to figure out the anticorrosion activity of Acacia Cyanophylla (Saligna leaves) extract on the corrosion of mild steel in dilute sulfuric acid medium, using weight loss measurements and electrochemical impedance spectroscopy. The result of the study revealed that the extract act as a potent inhibitor on mild steel in acid medium. The increase in inhibitor concentration and immersion time showed a positive effect on inhibition efficiency. EIS exhibited one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. The increase of phase shift (n) in presence of (ACLE) lower surface roughness. This change reveals the adsorption of the inhibitor compound on the steel surface. According to the results of weight loss measurements, the adsorption of the extract on the steel surface can be described by the Langmuir isotherm. The inhibition mechanism of (ACLE) molecules involves physical interaction between the inhibitor and metal surface. Additionally, Protective film formation against acid attack was confirmed by FT-IR and AFM techniques.
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Abstract

Metallic bearing alloys have different types, most of which are tin (Babbitt) or bronze based. Bronze bearings are used at heavy duty conditions. The goal of this research is an investigation on the effect of cooling rate and pouring temperature (two important factors in casting production) on the Brinell hardness and pin-on-disc wear resistance (two important properties in bearing applications) of bronze SAE660. The melt had prepared by induction furnace. Then, it had poured in sand mold in four different casting conditions, including pouring temperatures of 950 oC and 1200 oC, and cooling with water and air. Finally, the microstructure, hardness and wear resistance of the SAE660 had investigated. The results indicated that if the maximum hardness, along with the minimum weight loss due to wear (or maximum wear resistance) is required; the contents of intermetallic compounds, lead phase and the solid solution phase should be more. In this way, the samples which are cooled in air and poured at 950 oC have the high hardness and the lowest weight loss.
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Abstract

An intentional change in material properties is an important condition for castings production. It is one way how to meet the casting requirements of how to adapt the material properties to the operating conditions. Centrifugally cast rolls are multi-layer rollers, castings. The working layer of the barrel is called the "shell" and the body of the roll and the necks rolls are called "core". The article deals with the influence of the properties of the core iron. Earlier laboratory experiments were primary analysed for metallographic analysis and mechanical properties. These data were compared back to the experiments. The results of these laboratory working were later applied in the operating conditions of the roll foundry Vítkovitcké slévárny, spol. s r.o. The spun cast roll produced with the applied metallurgical processing change was supplied to the hot strip mill. There were monitored the positive effect of the change of the metallurgical process of the production of the core iron on the useful properties of the centrifugally cast roll. The experiment was done in order to increase the mechanical properties of ductile pearlite ductile iron. The copper in these core iron material increases the hardness and strength primarily.
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Abstract

The paper contains the results of the initial surface treatment influence on the properties of the medical Ti-6Al-7Nb alloy with a modified zirconium oxide layer deposited on its surface by sol-gel method. In the paper, the analysis of results of potentiodynamic studies is presented as well as its resistance to pitting corrosion and electrochemical impedance spectroscopy (EIS), macroscopic observation of the surface of samples and analysis of geometrical structure with the use Atomic Force Microscope (AFM) were performed. The studies were performed on two groups of samples depending on the graduation of the sand used in sandblasted process – 50 μm and 250 μm. Based on the obtained results it can be concluded that the type of the initial surface treatment preceding the surface modification of the Ti-6Al-7Nb has a significant effect on its properties.
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Abstract

Rock glaciers are lobate or tongue-shaped landforms which consist of rock debris and have either an ice core or an ice-cemented matrix. Characteristics such as the landscape setting, morphology, material and current geomorphological state are universally used to classify rock glaciers. In Antarctica, rock glaciers have only been surveyed on the Antarctic Peninsula, Ellsworth Mountains and in Victoria Land. This paper presents the first data on the identification and description of rock glaciers in the Jutulsessen nunataks, Dronning Maud Land, East Antarctica. The rock glaciers in the Jutulsessen exhibit a variety of morphologies and states. Our data suggests that the rock glaciers in Brugdedalen and Jutuldalen are active, while the features at Vassdalen and Grjotlia are considered inactive, and a feature at Grjotøyra is considered relict. The described rock glaciers do not fit into existing classification systems and appear to be different to alpine, Arctic and Andean rock glaciers. They further present examples that fit both the ‘glaciogenic’ and ‘permafrost’ development theories.
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Abstract

Concerns about food quality and environmental protection have led to the search for effective and safe insect control measures. This study was carried out to evaluate the efficacy of some insecticides (malathion, alpha-cypermethrin, lambda-cyhalothrin) and clove oil, alone and in combinations, to protect wheat grain against Rhyzopertha dominica. Adult mortality, progeny emergence and weight loss of treated grain were examined. The results revealed that the tested insecticides and clove oil alone showed high efficiency to R. dominica with respect to mortality, progeny of the adults and weight loss of wheat grain. The mixing of lambda-cyhalothrin and clove oil with the most effective insecticide (alphacypermethrin) enhanced its efficacy to R. dominica. It was more efficient against R. dominica than when used alone with respect to mortality and progeny of the adults. However, mixing alpha-cypermethrin with malathion reduced the efficacy of alpha-cypermethrin against R. dominica with respect to mortality and progeny of the adults. Combinations of alpha-cypermethrin and clove oil reduced wheat grain loss more than using them alone. Mixing lambda-cyhalothrin and clove oil with low concentrations of alpha-cypermethrin improved its efficacy against R. dominica and therefore may reduce environmental pollution, lower risks to human health, and delay insect resistance development.
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Abstract

The aim of the present work was to evaluate the selectivity of nicosulfuron, alone and in combinations, applied in post-emergence (V4) of glyphosate and sulfonylurea tolerant (RR/STS) soybean. The experiments were conducted in 2015/16 and 2016/17, in Piracicaba – state of São Paulo (SP). In 2016/17, the experiment was also conducted in Palotina – state of Paraná (PR). The experiment was a randomized block design, with four repetitions and 16 treatments, with combinations of nicosulfuron, glyphosate, chlorimuron, sulfometuron and cloransulam, applied alone or in tank mixture. Crop injury and variables related to agronomic performance were evaluated. Data were subjected to analysis of variance and treatment means were compared by the Tukey test. The results obtained are significant in the positioning of herbicides in RR/STS soybean, since in the five experiments, all the treatments were selective, except for glyphosate + sulfometuron which reduced the yield of a cultivar (CD 2630 RR/STS) in the 2015/16 season.
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Abstract

In August 2016, tomato plants grown during a hot, wet summer with heavy soil flooding, displaying symptoms of wilting, dead plant, root rot with crown and stem rot, at Beni Suef and Fayoum governorates were examined. A number of 16 fungal isolates were isolated from tomato plants displaying the above symptoms. These isolates were classified as belonging to six species, namely: Alternaria solani, Chaetomium globosum, Fusarium solani, Fusarium oxysporum, Pythium spp. and Rhizoctonia solani. Isolates of Pythium spp. were prevalent and were found to be more pathogenic than the other fungal isolates. This species causes damping-off, root rot, sudden death, stem rot and fruit rot. The pathogen was identified as Pythium aphanidermatum based on morphological, cultural, and molecular characteristics. Biogenic silver nanoparticles (AgNPs) were produced using the F. oxysporum strain and characterized by transmission electron microscopy (TEM). The size of these spherical particles ranged from 10 to 30 nm. In vitro, biogenic AgNPs showed antifungal activity against P. aphanidermatum. In greenhouse and field experiments, AgNPs treatment significantly reduced the incidence of dead tomato plants due to root rot caused by P. aphanidermatum compared to the control. All of the investigated treatments were effective and the treatment of root dipping plus soil drenching was the most effective. To the best of our knowledge, this study describes P. aphanidermatum on tomato in Egypt for the first time. Also, biogenic AgNPs could be used for controlling root rot disease caused by this pathogen.
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Abstract

Potato virus Y (PVY) is one of the most destructive viruses infecting potato in Egypt and worldwide. Recent research has shown that a necrotic PVY-NTN strain is infecting potato in Upper Egypt. Chemical control is not effective to control this viral pathogen. An alternative to control PVY infecting potato is using a mild PVY strain to elicit systemic cross protection in potato plants against infection with a severe necrotic strain of PVY. Results of this study showed that a PVY necrotic strain produced a significant lesser number of local lesions on diagnostic plants (Robinia pseudoacacia L.) when these plants were treated first with a mild PVY strain. Data obtained from greenhouse and field experiments indicated that treatment of potato plants (variety Burna) with a mild PVY strain significantly protected potato from infection with a severe necrotic PVY strain, and resulted in a significant increase in tuber yield compared with infected plants without prior treatment with a mild PVY strain. The highest increase in potato tuber yield was obtained when potato plants were inoculated with a mild PVY strain 3 days before challenging with the severe necrotic PVY strain. This study proved that using a mild strain of PVY can significantly protect potato plants from infection with a severe strain of this virus under both greenhouse and field conditions and can present a potential method to reduce losses due to infection of this virus in Assiut governorate and Upper Egypt.
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Abstract

Control failure of pests and selectivity of insecticides to beneficial arthropods are key data for the implementation of Integrated Pest Management (IPM) programs. Therefore, the aim of this study was to assess the control failure likelihood of Plutella xylostella and the physiological selectivity active ingredients to parasitoid Oomyzus sokolowskii (Hymenoptera: Eulophidae) and to predators Polybia scutellaris (Hymenoptera: Vespidae) and Lasiochilus sp. (Hemiptera: Anthocoridae). In bioassays, P. xylostella larvae and O. sokolowskii, P. scutellaris and Lasiochilus sp. adults were used. Concentration-mortality curves of six insecticides for P. xylostella were established. These curves were used to estimate the mortality of P. xylostella at the recommended concentration, in order to check a control failure of insecticides to this pest. Furthermore, the lethal concentration for 90% of populations (LC90) and the half of LC90 were used in bioassays with the natural enemies to determine the selectivity of these insects to insecticides. All tested insecticides showed control failure to P. xylostella, indicated by high LC90 and low estimated mortalities (less than 80%). The cartap insecticide was selective in half of LC90 to Lasiochilus sp. and moderately selective in LC90 and the half of LC90, to Lasiochilus sp. and P. scutellaris, respectively. Deltamethrin was moderately selective in the half of LC90 to predator Lasiochilus sp. Cartap, carbaryl, and deltamethrin reduced the mortality of Lasiochilus sp. in the half LC90. The results also showed that the insecticides methamidophos, carbaryl, parathion methyl and permethrin were not selective to any of the tested natural enemies. The role of insecticides in IPM systems of Brassica crops is discussed based on their control failures to P. xylostella and selectivity to their natural enemies.
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Abstract

Potato white mold caused by Sclerotinia sclerotiorum is an important plant disease occurring in many potato-producing areas throughout the world. In this study, a specific diagnostic method was used to detect and quantify S. sclerotiorum ascospores, and its forecasting ability was assessed in potato fields during flowering periods of 2011 to 2014 in Bahar County, Hamedan Province. Using GenEMBL database, a primer pair, HZSCREV and HZSCFOR, was designed and optimized for the pathogen. After testing the sensitivity of primers, DNA was extracted from samples of outdoor Burkard traps from potato fields. A linear association was observed between pathogen DNA and the number of ascospores using the quantitative PCR (qPCR) technique in the presence of SYBR dye. The qPCR could successfully detect DNA amounts representing two S. sclerotiorum ascospores and was not sensitive to a variety of tested fungi such as Botrytis cinerea, Alternaria brassicae, Fusarium solani. In contrast to the amount of rainfall, a direct relationship was found between ascospore numbers and the incidence of potato white mold from 2011 to 2014.
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Abstract

Quantitative resistance in barley to four Fusarium head blight (FHB) species was investigated in vitro. Nine components involved in three assays (detached leaf, modified Petridish and seedling tests) were compared on two widely grown Syrian barley cultivars: Arabi Aswad (AS) and Arabi Abiad (AB). On AB, inoculation with FHB species resulted in a significantly shorter latent period and larger lesion length of detached leaf inoculation, more standardized area under disease progress curve (AUDPCstandard) of modified Petridish inoculation and a higher percentage of infected seedlings of pin-point inoculation than on AS. The latent period of AB was 14.89% less than AS, lesion length of AS was 6.01% less than AB, AUDPCstandard of AS was 17.07% less than AB and the percentage of infected seedlings of AS was 4.87% less than AB. Inoculation with FHB species resulted in no significant differences in the other five components measured: incubation period of detached leaf inoculation, germination rate reduction and coleoptile length reduction of modified Petridish inoculation, percentage of infected seedlings of foliar-spraying inoculation and lesion length of clip-dipping inoculation. AS was more resistant to in vitro FHB infection than AB. The latent period and AUDPCstandard recorded the highest values compared with the lowest values for lesion length and percentage of infected seedlings. It seems that measurement of the latent period and AUDPCstandard may be useful in identifying barley cultivars which are highly susceptible or resistant to FHB at early stages.
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Abstract

The response of the Mi-1 gene to different densities of Meloidogyne incognita race 2 was investigated under controlled conditions. Susceptible and resistant tomato seedlings were inoculated with 25, 50, 100, 200, 400, 1000, 2000, 5000 and 10000 second-stage juveniles of M. incognita. Plants were uprooted 8 weeks after inoculation and the numbers of egg masses and galls on the roots, and second-stage juveniles in 100 g soil per pot were counted. In susceptible plants, there was a correlation between the number of egg masses on roots until 2000 J2 inoculum densities. In resistant plants, when inoculum densities increased, the number of egg masses and galls also increased. The reproduction factor ratio was >1 in the susceptible plant and <1 in the resistant plant. The data showed that the 5000 J2 inoculum was a critical limit, and 10000 J2s were above threshold for resistant plants. The data indicate that densities of M. incognita can seriously affect the performance of the Mi-1 gene.
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Abstract

Biological control of plant diseases is strongly emerging as an effective alternative to the use of chemical pesticides and fungicides. Stress tolerance is an important attribute in the selection of bacteria for the development of microbial inoculants. Fourteen salt-tolerant bacteria showing different morphological features isolated from the rhizosphere of maize were evaluated for different plant growth-promoting activities. All isolates showed auxin production ranging from 5 to 24 μg ⋅ ml–1 after 48 h incubation in tryptophan supplemented media. Phosphate solubilization ranged from 15 to 419 μg ⋅ ml–1. 1-aminocycloproprane- 1-carboxylate (ACC) deaminase activity was shown by 6 isolates, ammonia production by 9 isolates, siderophore production by 8 isolates while HCN production by 4 isolates. Four bacterial isolates with all plant growth-promoting properties also showed strong antagonistic activities against Fusarium oxysporum, F. verticillioides, Curvularia lunata and Alternaria alternata and abiotic stress tolerance against salinity, temperature, pH and calcium salts. Two selected bacterial isolates significantly enhanced the growth of pea and maize test plants under greenhouse conditions. The bacterial isolate M1B2, which showed the highest growth promotion of test plants, was identified as Bacillus sp. based on phenotypic and 16S rDNA gene sequencing. The results indicated that Bacillus sp. M1B2 is a potential candidate for the development of microbial inoculants in stressful environments.
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Abstract

Severe leaf spot disease was observed on Aloe vera plants in the winters of 2011 and 2012 during a survey of various nurseries of Gwalior, India. Irregular, sunken, dark creamish brown spots having reddish brown margin were noticed on both surfaces of the leaves. The causal organism was consistently isolated from symptomatic leaves on potato dextrose agar media (PDA). A total 59 isolates of fungi were recovered from diseased A. vera leaves, and 37 isolates were identified as belonging to the genus Fusarium. On the basis of morphological characteristics and internal transcribed spacer (ITS) region of rDNA amplified using the primers ITS4/ITS5 the pathogen was identified as Fusarium proliferatum (Matsushima) Nirenberg and pathogenicity of the isolate was confirmed by using Koch’s postulates. To the best of our knowledge, this is the first report of leaf spot disease caused by Fusarium proliferatum on A. vera plants in India.
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