1,720,986 research outputs found
Study on influence of flow rates on voids in waxy crude oil subjected to dynamic and static cooling
No full textThe assumption of constant yield stress in the conventional restart pressure equation
neglects the effects of thermal shrinkage and gas voids formation, which in turn resulted
in an over-designed production piping systems. This paper presents a study on the effects
of flow rates on the formation of voids in gelled waxy crude oil. A flow loop rig simulating
offshore waxy crude oil transportation was used to produce a gel. A Magnetic Resonance
Imaging (MRI) was used to scan the gelled crude oil over the three planes. Waxy crude oil
underwent both dynamic and static cooling to observe the effects of volume flow rates on
the voids formed in wax-oil gel. Volume flow rate was found to have different influences
on the intra-gel voids in the pipeline. A volume flow rate of 5 L/min resulted in a maximum
total voids volume of 6.98% while 20 L/min produced a minimum total voids volume of
5.67% in the entire pipe. Slow flow rates resulted in a larger voids volume near the pipe
wall. In contrast, faster flow rates produced insignificantly higher voids volume around
pipe core. Generally, slower flow rates favoured the formation of higher total voids volume
following sufficient steady time of wax crystal formation, producing larger voids areas in
gelled waxy crude oil
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Yield and Quality of Malt Barley (Hordeum vulgare L.) in Response to Special Liquid Fertilizer (Trafos Synergy) Application in the Central Highlands of Ethiopia
Full text linkFertilizer application requirement to crops varies from location to location due to several factors. Thus, there is a need to evaluate response of yield and quality of malt barley to liquid fertilizer applications. Accordingly, an experiment was conducted to evaluate different dose of liquid fertilizer applications on yield and yield components of malt barley at Welmera (Holeta and Telecho) and Ejere (Cheri) districts during 2016 and 2017 main cropping season. The experiment was laid out in randomized complete block design with four replications. The treatments were different doses of Trafos synergy with the recommended NP, that is,0, 100% NP, 100% NP + Trafos synergy 4 L/ha, 100% NP + Trafos synergy 2 L/ha and 100% NP + Trafos synergy 6 L/ha). Applications of recommended NP and Trafos synergy liquid nutrient sources in combination had a significant (p<0.05) effect on grain and biomass yield of malt barley. The highest grain yield (3251.1kg/ha) was obtained from the application of 100% NP + Trafos synergy 6 L/ha) at Cheri. Based on economic analysis, application of 100% recommended NP with Trafos synergy 4 L/ha fertilizer at HARC and Cheri site indicates promising for barley production on yield and grain quality. Keywords: Grain quality, Trafos synergy, protein content DOI: 10.7176/JBAH/9-3-0
Response of Malt Barley to Special Liquid Fertilizer (Rutter AA) in the Central Highlands of Ethiopia
Full text linkThe experiment was conducted at Welmera (Holeta &Telecho) and Ejere (Cheri) districts during 2016 and 2017 main cropping season to evaluate response of yield and yield components of malt barley to special liquid fertilizer (Rutter AA) applications. The experiment was laid out in randomized complete block design with three replications. The treatments were different doses of Ruter AA with recommended NP, that is,0, 100% NP, 100% NP + Ruter AA 4 L/ha, 100% NP + Ruter AA 2 L/ha and 100% NP + Ruter AA 6 L/ha). The results of this study indicated that the productivity of malt barley was significantly affected by different dose of Ruter AA applied. Applications of 100% NP fertilizer with Ruter AA liquid nutrient sources combination had a significant (p<0.05) effect on grain yield and biomass yield of malt barley. In general application of liquid fertilizer (Rutter AA) indicates positive response on grain quality of malt barley. In conclusion, based on the findings of the experiment without application of liquid fertilizer but 100% recommended NP fertilizer are economically optimum for malt barley production with acceptable grain quality in the Holeta, Cheri and Telecho study sites. Keywords: Grain yield, Liquid fertilizer, Protein content DOI: 10.7176/JNSR/9-2-0
Phosphorus Response and Fertilizer Recommendations under Balanced Fertilizers for Tef (Eragrostis tef) Grown on Vertisol in the Central Highlands of Ethiopia
Full text linkPhosphorous response and fertilizer recommendation under balanced fertilizer study was conducted for tef grown on Vertisols in Dendi district, West Shewa, in central highlands of Ethiopia. The experiment was arranged in a complete block design with six levels of phosphorous fertilizer (0, 10, 20, 30 and 40 kg ha-1) with three replications. Based on a yield difference between the control and the P treatments, 80% of sites responded to P fertilizer. The application of phosphorous fertilizer at different rates increased grain yield of tef, up to 13.6% as compared to the control (zero p treatment). Extractable soil P concentrations (Olsen method, 0- 20 cm depth) three weeks after planting significantly responded to P fertilizer rate. Correlations of relative yield soil phosphorous values showed that the soil phosphorous levels greater than 15.6 mg kg-1 (critical phosphorous concentration) was found to be sufficient for tef production. The average phosphorous requirement factor (Pf) calculated from soil phosphorous values of all treatments for the study area was 12.6. In the absence of a soil test, a recommendation of 30 kg P ha-1 to prevent a potential loss of tef. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices. Keywords: Critical P concentration, Phosphorus, Relative yield, Tef, Vertisol DOI: 10.7176/JNSR/11-20-01 Publication date:October 31st 202
Combination of Organic and Inorganic Fertilizer Improves Wheat Yields and Soil Properties on Nitisols of Central highlands of Ethiopia
Full text linkA field experiment was conducted for three consecutive cropping seasons (2015-2017) on farmers’ fields in Welmera district of Oromiya Regional State with the objective of quantifying the effect of organic and inorganic fertilizers on growth and yield of wheat and soil chemical properties. The treatments included eleven selected combinations of organic and inorganic nutrient sources including farm yard manure, Compost, Nitrogen and Phosphorus application. The experimental design was randomized complete block with three replications. Results showed that wheat yield, yield components and soil chemical properties were significantly affected by the application of organic and inorganic fertilizer sources. The highest wheat(Triticum aestivum L.) grain yield (4278.1 kg/ha) and biomass yield (1385.5kg/ha) were obtained from the applications of half doses of compost which is based on recommended N equivalent and half doses of the recommended nitrogen and phosphorus fertilizers (30kg/ha N and 34.5kg/ha P that half dose contains) followed by 4269.4 kg/ha and 13711.7 kg/ha for grain yield and biomass yield, respectively, due to the application of the full recommended N and P rates (60kg N/ha and 69kg P/ha)from inorganic fertilizers. Application of organic fertilizer improved organic carbon from 1.08% to 1.86%, total N from 0.14% to 0.28%, available phosphorous from 6.35ppm to 18.14pmm and pH from 4.04 to 5.08. The highest marginal rate of return was obtained from application of 75% compost (based on equivalent N rate) plus 25% N and P, which is economically the most profitable on Nitisols of the central Ethiopian highlands. Keywords: Compost, Farm yard manure, Nitisols, Nitrogen, Phosphorus DOI: 10.7176/JBAH/9-4-0
Evaluation of Potassium Fertilizer on Yield and Yield Components of Potato under Irrigation on Nitisols in Central Highlands of Ethiopia
Full text linkNutrient deficiency is a major constraint for potato (Solanum tuberosum L.) production in Ethiopia. Potato response to potassium fertilizer declined with widespread deficiencies of nutrients other than N and P, farmers are discouraged to apply such fertilizer recommendations. This study was, therefore, conducted for two years (2018-2019) on nitisols under irrigation to evaluate the response of potato to potassium (K) fertilizer rates. The treatments were five (Negative control, recommended NPS, recommended NPS, recommended NPS + 3liter K /ha, recommended NPS + 5 liter K/ha, recommended NPS + 7liter K/ha). The experiment was arranged in a randomized complete block design replicated four times on farmers’ fields. Results revealed that potato yield responded differently to the applied potassium fertilizer rates. Applications of 100% NP fertilizer with 5liter/ha potassium fertilizer had a significant (p<0.05) effect on marketable tuber and total tuber yield of potato. In general application of liquid potassium fertilizer (100% NP fertilizer with 5liter/ha K) indicates positive response on dray matter and specific gravity. In conclusion, based on the findings of the experiment with application of 5L/ha liquid potassium fertilizer with 100% recommended NP fertilizer are economically optimum for potato production. Keywords: Liquid fertilizer, Nitisols, Potassium, Potato DOI: 10.7176/JNSR/10-12-02 Publication date:June 30th 202
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