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การศึกษาการย่อยสลายทางชีวภาพของยางธรรมชาติดัดแปรเพื่อเป็นแนวทางในการจัดการของเสียจากยางธรรมชาติ
Get PDFStudy on Biodegradation of Modified Natural Rubber to Serve as Guidelines for Natural Rubber Waste Management
Phetdaphat Boonsuk
รับบทความ: 23 ตุลาคม 2566; แก้ไขบทความ: 8 เมษายน 2567; ยอมรับตีพิมพ์: 8 เมษายน 2567; ตีพิมพ์ออนไลน์: 10 พฤษภาคม 2567
บทคัดย่อ
ยางธรรมชาติและผลิตภัณฑ์จากยางธรรมชาติมีการผลิตและการใช้เพิ่มขึ้นในทุกวัน ก่อให้ เกิดปัญหาในการจัดการของเสียจากยางธรรมชาติ เนื่องจากการย่อยสลายทางชีวภาพเกิดขึ้นได้ยาก งานวิจัยนี้จึงมุ่งเน้นดัดแปรยางธรรมชาติโดยนำยางธรรมชาติ (NR) กราฟต์แป้งมันสำปะหลังดัดแปร (CST) ที่มีสัดส่วน CST 50 phr (NR–g–CST 50 phr) เพื่อศึกษาการย่อยสลายทางชีวภาพและเปรียบ-เทียบกับแป้งมันสำปะหลังดัดแปรร้อยละ 10 โดยน้ำหนัก (CST) ยางธรรมชาติผสมกับแป้งมันสำปะ-หลังดัดแปรที่มีสัดส่วน CST 50 phr (พอลิเมอร์ผสม NR/CST 50 phr) ยางธรรมชาติกราฟต์กับแป้งมันสำปะหลังดัดแปรที่มีสัดส่วน CST 50 phr และผสมกลีเซอรอลร้อยละ 3 โดยน้ำหนัก (พอลิเมอร์ผสม NS–GE) ยางพรีวัลคาไนซ์ผสมกับแป้งมันสำปะหลังดัดแปรที่มีสัดส่วน CST 50 phr (พอลิเมอร์ผสม PR/CST 50 phr) ยางธรรมชาติร้อยละ 30 DRC (NR 30% DRC) ยางพรีวัลคาไนซ์ร้อยละ 30 DRC (PR 30% DRC) และถุงมือยาง โดยนำแผ่นฟิล์มตัวอย่างฝังกลบในดินธรรมชาติ พบว่า แผ่น ฟิล์ม CST ย่อยสลายทางชีวภาพได้ประมาณร้อยละ 97 โดยน้ำหนัก ใน 8 สัปดาห์ แผ่นฟิล์ม NR–g–CST 50 phr ย่อยสลายทางชีวภาพได้หมดใน 12 สัปดาห์ แผ่นฟิล์ม NS–GE NR/CST 50 phr PR/ CST 50 phr PR 30% DRC NR 30% DRC และถุงมือยาง ย่อยสลายทางชีวภาพได้ประมาณร้อยละ 54 53 52 38 32 และ 24 โดยน้ำหนักใน 24 สัปดาห์ ตามลำดับ การศึกษาลักษณะทางกายภาพและโครงสร้างเคมีก่อนและหลังการฝังดิน พบว่า มีการเปลี่ยนแปลงที่เกี่ยวข้องกับการย่อยสลายทางชีวภาพ ดังนั้นการดัดแปรยางธรรมชาติโดยนำยางธรรมชาติกราฟต์แป้งมันสำปะหลังดัดแปรที่มีสัดส่วน CST 50 phr สามารถนำไปประยุกต์ใช้เป็นแนวทางในการปรับปรุงและพัฒนายางธรรมชาติและผลิตภัณฑ์จากยางธรรมชาติให้สามารถย่อยสลายทางชีวภาพได้ และเป็นแนวทางในการจัดการของเสียจากยางธรรมชาติและผลิตภัณฑ์ยางธรรมชาติในสิ่งแวดล้อมต่อไป
คำสำคัญ: การย่อยสลายทางชีวภาพ ยางธรรมชาติ แป้งมันสำปะหลัง การดัดแปรโครงสร้าง ยางธรรมชาติย่อยสลายได้ทางชีวภาพ
Abstract
Natural rubber and its products have been produced and used increasingly every day. This has caused waste management problem because biodegradation is difficult to occur. Therefore, this research focused on the modification of natural rubber with grafted natural rubber with modified cassava starch at the ratio of 50 phr (NR–g–CST 50 phr) for study on biodegradation by compare with modified cassava starch 10% by weight (CST), natural rubber blended with modified cassava starch at the ratio of 50 phr (NR/CST 50 phr), natural rubber grafted with modified cassava starch at the ratio of 50 phr and glycerol 3% by weight (NS–GE), pre–vulcanized rubber blended with modified cassava starch at the ratio of 50 phr (PR/CST 50 phr), natural rubber 30% DRC (NR 30% DRC), pre–vulcanized rubber 30% DRC (PR 30% DRC) and rubber gloves which buried in natural soil. It was found that the CST film was biodegraded about 97 wt% within 8 weeks. The NR–g–CST 50 phr film was completely biodegraded within 12 weeks. The NS–GE, NR/CST 50 phr, PR/CST 50 phr, PR 30% DRC, NR 30% DRC and rubber gloves films were biodegraded about 54 wt%, 53 wt% 52 wt%, 38 wt%, 32 wt% and 24 wt% within 24 weeks, respectively. From the study of physical appearance and chemical structures before and after burial, it was found that there were changes related to biodegradation. Therefore, NR modification by grafting modified CST at the ratio of 50 phr can be applied as guideline for the development of biodegradable NR and its products and for the waste management of NR and its products in the environment in the future.
Keywords: Biodegradation, Natural rubber, Cassava starch, Structure modification, Biodegradable natural rubbe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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