Volume 1, Number 1, 2021
Properties of Particleboard Made from Recycled Polystyrene and Cocos Nucifera Stem Particles
Abstract
The study investigates the use of Recycled Polystyrene (RP) in the production of particleboard. Boards of 6mm thickness with dimension of 350 mm x 350 mm were produced from mixture of Cocos nucifera stem particles and RP. The boards were made at varying mixing ratio of 1:1, 2:1, and 3:1
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The study investigates the use of Recycled Polystyrene (RP) in the production of particleboard. Boards of 6mm thickness with dimension of 350 mm x 350 mm were produced from mixture of Cocos nucifera stem particles and RP. The boards were made at varying mixing ratio of 1:1, 2:1, and 3:1 and board densities of 1000 kg/m3 1100 kg/m3 and 1200 kg/m3. Thickness swelling (TS), Water Absorption (WA), Modulus of Rupture, and Modulus of Elasticity of the boards were evaluated in accordance to ASTM D-1037 standard. Data obtained were subjected to analysis of variance (ANOVA) at 5% probability level. TS and WA decreases as the mixing ratio increases from 1:1 to 3:1 and board density increases from 1000 kg/m3 to 1200 kg/m3. Also, MOR and MOE of boards increase as the board density was increased from 1000 kg/m3 to 1200 kg/m3. However, MOR and MOE of boards initially increase as mixing ratio increases from 1:1 to 2:1 and later decreases with further increase in mixing ratio. The strongest and most dimensionally stable board was produced at board 1200 kg/m3 and mixing ratio 2:1. This study proves that RP is a good substitute for formaldehyde based resin commonly used in particle boards industries.Full article
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Article
Acoustic Properties of Musanga Cecrepoides Wood Samples Obtained from Different Stem Positions in Niger Delta Region of Nigeria
Abstract
Musanga cecrepoides is an interesting wood species due to its diverse utility ranging from medicine, shade, ornaments etc. Research has been conducted on other properties of this wood species with little information about its acoustic properties. Thus, the evaluation of its acoustic properties is pertinent so as to increase the
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Musanga cecrepoides is an interesting wood species due to its diverse utility ranging from medicine, shade, ornaments etc. Research has been conducted on other properties of this wood species with little information about its acoustic properties. Thus, the evaluation of its acoustic properties is pertinent so as to increase the information bank of its properties. This study assessed the acoustic properties of Musanga cecrepoides wood obtained from selected states and locations in the Niger Delta region of Nigerian viz a vis, Rivers, Bayelsa and Delta States. Test samples were collected from different stem positions axially (top, middle, base) and radially (inner and outer) and analyzed using the statistical software package IBM SPSS Statistics, Version 23 (IBM Corporation, New York, USA). Analysis of variance (ANOVA) was performed at 5% level of significance to determine whether the assessed acoustic properties were significantly different among different stem positions. Results showed that sound frequency (f) at top wood (3061.71 Hz) and outer wood (3096.06 Hz) had significantly higher resonance frequency compared with the bottom wood (2768.01 Hz) and inner wood (2349.54 Hz) respectively. The mean sound velocity (v) at both the axial (2069.59 m/s) and radial (1905.96 m/s) stem positions fell short of the estimated mean v of other wood species when compared. However, such result is suitable for other acoustic purposes with moderate sound velocity. The sound radiation coefficient (R) values were highest at the bottom (4.18) axially and outer (4.13) radially when compared to other stem orientations of the wood. Whereas axially at the top (1561815.86 Kg/(m2s)) and radially at the outer position (1558292.53 Kg/(m2s) Sound Impedance (z) was highest when compared with other stem positions of the Musanga cecrepoides wood.Full article
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Article
Evaluation of the Effect of Azospirillum Brasilense and Mycorrhizal Fungi of the Soil in Yacón Grown in a Greenhouse
Abstract
In order to evaluate the effect of Azospirillum brasilense and mycorrhizal fungi in the soil on the nutrition of the yacon crop (Smallanthus sonchifolius [(Poeppig & Endlicher) H. Robinson]), determinations of agronomic parameters and the health status of the plants were carried out, under greenhouse conditions. The tests were carried
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In order to evaluate the effect of Azospirillum brasilense and mycorrhizal fungi in the soil on the nutrition of the yacon crop (Smallanthus sonchifolius [(Poeppig & Endlicher) H. Robinson]), determinations of agronomic parameters and the health status of the plants were carried out, under greenhouse conditions. The tests were carried out at the time of the implantation of the culture: the propagules were inoculated with A. brasilense and with native mycorrhizal fungi, generating four treatments, including the control and the co-inoculation of the consortium of the microorganisms under study (T0: control or control without inoculation; T1: inoculation with native A. brasilense; T2: inoculation with native mycorrhizal fungi and T3: joint inoculation with A. brasilense and native mycorrhizal fungi. The results indicate that co-inoculation with A. brasilense and native mycorrhizal fungi increased plant growth in height, leaf area, biomass, dry matter and yields significantly in greenhouse production. It was determined that the application of the selected microorganisms has a plant growth promoting effect, increasing growth and productivity, greenhouse grown yacón.Full article
Article
Ultrasonography in Sheep Follicular Dynamics
Abstract
The first visualizations of the structures of the sheep's reproductive system, whether of the uterus or ovaries, were performed through exploratory laparotomies, laparoscopies or through materials obtained in slaughterhouse, being possible to evaluate only what was happening at that moment in the estrous cycle. With the emergence of ultrasound from
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The first visualizations of the structures of the sheep's reproductive system, whether of the uterus or ovaries, were performed through exploratory laparotomies, laparoscopies or through materials obtained in slaughterhouse, being possible to evaluate only what was happening at that moment in the estrous cycle. With the emergence of ultrasound from the 90s, it became possible to dynamically monitor what happened at each moment of the estrous cycle at different times of the year, without having to slaughter the females. Because it is a non-invasive technique and the stress caused by its use is very low, it is increasingly necessary to use ultrasound in sheep, either for pregnancy diagnosis or for multiplying herds using biotechnologies, which the ultrasound examination becomes indispensable to obtain the best results. This review aims to describe the main advances in the study of the estrous cycle of sheep with the help of ultrasonography and its influence on the productive efficiency of the herd.Full article
Review Article
Soybean Agronomic Performance Does Not Change with Gypsum Application in a Cambisol Submitted to Water Re-striction in Southern Brazil
Abstract
Water stress is a limiting factors for soybean crop development, and it may increase due to subsurface soil acidity. The use of agricultural gypsum is a way to improve the soil chemical conditions at depth and mitigate the undesirable effects caused by water restriction during drought periods. This study aimed
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Water stress is a limiting factors for soybean crop development, and it may increase due to subsurface soil acidity. The use of agricultural gypsum is a way to improve the soil chemical conditions at depth and mitigate the undesirable effects caused by water restriction during drought periods. This study aimed to evaluate whether gypsum application increases soybean yield in water restriction conditions. The experiment was implemented in 2018 in a Humic Cambisol, Southern Brazil. The treatments consisted of two gypsum management procedures (with 1.4 Mg ha-1 and without application) associated with two water conditions (with and without water restriction). The water conditions were promoted by partially covering the soil with plastic tarpaulin sheets. Soybean was grown in the crop years 2018/19 and 2019/20 to assess root attributes and yield and were analyzed soil chemical characteristics. Water restriction reduced soybean yield by 11.4 and 36.8% in the 2018/19 and 2019/20 harvests, respectively, whereas there was no response to gypsum application. The plants’ root system was not affected by the water conditions or gypsum management. It was concluded that water restriction reduces soybean yield, and agricultural gypsum does not mitigate such loss under the evaluated conditions, even though it positively changes some soil chemical parameters.Full article
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Article
Occurrence of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) in Rhipicephalus microplus (Canestrini 1888) (Acari: Ixodidae)
Abstract
The tick Rhipicephalus microplus (Canestrini 1888) (Acari: Ixodidae) is responsible for considerable economic losses in Brazil. The Chrysopidae family comprises a large number of species, one of the most important being the species Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae). The aim of this study is to describe the incidence of C.
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The tick Rhipicephalus microplus (Canestrini 1888) (Acari: Ixodidae) is responsible for considerable economic losses in Brazil. The Chrysopidae family comprises a large number of species, one of the most important being the species Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae). The aim of this study is to describe the incidence of C. externa in R. microplus in Goiás, Brazil. Engorged females of R. microplus collected from naturally infested cattle were taken to the laboratory. For obtaining nymphs and other insects. From November 2013 to October 2014, 151 engorged females belonging to the species R. microplus were collected, from which one specimen of the species C. externa emerged. The percentage of predation was 0.6%.Full article
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Case Report
ISSN: 2769-8874
DOI prefix: 10.31586/ojar
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