1,721,187 research outputs found
Comparative study of nanoparticles and alcoholic fuel additives with optimized synthesis of palm-sesame biodiesel using tribological and internal combustion engine testing / Muhammad Mujtaba Abbas
No full textThe demand for renewable energy is steadily increasing due to the rise in population, economic development, and environmental issue globally. Renewable energy sources are now considered better replacements for fossil fuels. Meanwhile, up to 20% of liquid fuels such as methyl esters are currently being blended with petroleum fuels. Recently, the commercialization of biodiesel is a significant challenge due to its poor cold flow properties and oxidative stability. Poor cold flow properties and oxidative stability can be improved by selecting suitable vegetable oils for producing different blends. Among all available vegetable oils, sesame seed oil (SSO) has unique cold flow properties and oxidation stability. This research aimed to improve the cold flow, lubricity, and diesel engine characteristics of biodiesel produced from the palm-sesame oil blends. Response Surface Methodology (RSM) and Extreme Learning Machine (ELM) techniques were used to develop the production process, and the input variables (time, catalyst amount, methanol to oil ratio, and duty cycle) were optimized. The optimum yield of P50S50 (50% palm + 50% sesame) biodiesel obtained was 96.61 % under operating parameters such as time (38.96 min), duty cycle (59.52 %), methanol to oil ratio (60 V/V %), and catalyst amount (0.70 wt.%). The cold flow characteristics of P50S50 biodiesel were significantly improved, such as cloud point (7.89 ℃), pour point (3.80 ℃), and cold filter plugging point (− 1.77 ℃) with better oxidation stability of 6.89 h. During the test run, the friction coefficient was measured directly using the high-frequency reciprocating rig (HFRR). The results exhibited that B10 (Malaysian commercial diesel) demonstrated a poor coefficient of friction and wear scar diameter compared with other tested fuels. The addition of ethanol as a fuel additive in the B30 fuel sample reduced fuel lubricity and increased the wear and friction coefficient compared with other fuel additives. B30 fuel with titanium oxide (TiO2) nanoparticles exhibited improved results with the minimum wear scar diameter and lowest friction coefficient among all other fuel samples. Dilution of engine oil with unburned fuels changes its lubricity and tribological properties. Lubricating oil diluted with B10 showed a high coefficient of friction (COF) with severe abrasive and adhesive wear compared with mineral lubricant, among other fuels. Lubricant+B30+TiO2 showed the minimum increase in COF value among all other modified fuels compared to SAE-40 mineral lubricant. Engine performance and emissions characteristics were studied using a compression ignition (CI) diesel engine with variable engine rpm at full load conditions. The results were compared with B30 and B10 fuels. The main findings indicated that the B30+TiO2 ternary blend showed an overall decrease in brake-specific fuel consumption compared with other tested fuels. B30+DMC produced higher brake thermal efficiency, among other fuels. B30+DMC ternary blend showed a reduction in carbon monoxide (CO) and hydrocarbons (HC) emissions compared to B30. B30+CNT ternary blend showed a slight decrease in nitrogen oxide (NOx) emissions compared to B30. The research suggests that Palm-Sesame biodiesel with fuel additives is a suitable replacement for diesel fuel in compression ignition engines without engine modification
Identification of hazardous nature of well drilling operation with associated potential hazards at oil and gas extraction industries: an explanatory approach
No full textThis study illustrates about the most hazardous and risky activities associated with well drilling operation at on and offshore
oil and gas drilling sites by adopting exploratory research design (quantitative leading to qualitative). In this study researcher has
targeted three oil and gas industries each from Malaysia, Saudi Arabia and Pakistan for the identification of associated hazards
and nature of hazardous activities faced by drilling crew during well drilling operation. Eighty (80) drilling crew members have
been randomly selected for answering the survey questionnaire. Likewise, nine (09) drilling health and safety officials have been
conveniently selected based on their safety expertise in oil and gas drilling field for semi structured in-depth interview. For analyzing
quantitative findings descriptive statistical methods has been used. While for qualitative section thematic analysis approach has
been utilized. Based on the findings, respondents from Malaysian oil and gas industries reported starting drilling activity as highly
hazardous at onshore well drilling, while handling drilling pipe has been considered more hazardous activity at offshore domain.
Similarly, in the context of Saudi Arabia, respondents highlighted that the handling drilling pipes are cause of major injuries at onshore
well drilling site. Whereas drilling fluid preparation and coring process is considered harmful at offshore sites. In contrast, participant
from Pakistan indicated coring process as a highly hazardous activity at on and offshore well drilling operation. According to overall
results based on the participant response, oil and gas well drilling operation at onshore domain is considered more hazardous
at Pakistani oil and gas industry as compare to other targeted industries with mean range 3.42. While for offshore well drilling,
Malaysian industry is recorded highly hazardous as compare to others leading with mean value 3.39 and related with chemical and
safety hazards in well drilling activities
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
Comprehensive database of test transportation problems (balanced and unbalanced)
No full textThe database of test transportation problems presented with this article is a useful aid in assessing the accuracy of existing and new methods for finding initial basic feasible (IBF) or optimal solution of transportation problems. The optimal solutions of these using MODI method, and IBF solutions using some conventional methods are planned to be presented in a forthcoming research paper for easiness of the researchers working in this domain
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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