Loading…
Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior
The main purpose of this work is to prepare an efficient series of preformed particle gels (PPGs) and to study their behaviors to control unwanted water in oil fields. To this end, 12 copolymer samples composed of acrylamide and acrylic acid [poly(AAm- co -AA)] with different AAm/AA mole ratios and...
Saved in:
| Published in: | Journal of petroleum exploration and production technology 2018-12, Vol.8 (4), p.1331-1340 |
|---|---|
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| cited_by | cdi_FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203 |
|---|---|
| cites | cdi_FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203 |
| container_end_page | 1340 |
| container_issue | 4 |
| container_start_page | 1331 |
| container_title | Journal of petroleum exploration and production technology |
| container_volume | 8 |
| creator | Heidari, Samira Esmaeilzadeh, Feridun Mowla, Dariush Ghasemi, Sohila |
| description | The main purpose of this work is to prepare an efficient series of preformed particle gels (PPGs) and to study their behaviors to control unwanted water in oil fields. To this end, 12 copolymer samples composed of acrylamide and acrylic acid [poly(AAm-
co
-AA)] with different AAm/AA mole ratios and various mole percentages of
N
,
N
′-methylenebisacrylamide (MBA) were synthesized by a free radical copolymerization method. The gelation time of each sample was measured. The samples were dried in three consecutive steps: drying at atmospheric condition, drying in the oven, and drying in the vacuum oven, respectively. The chemical structure and morphology of the prepared PPGs were studied by a Fourier transform infrared spectroscopy and a scanning electron microscopy, respectively. Additionally, the swelling percentage of PPG samples was examined in different types of salt water (MgCl
2
·6H
2
O, CaCl
2
·2H
2
O, BaCl
2
·2H
2
O, NaCl, KCl, and LiCl) with 200,000 ppm concentration and pH in the range of 3–8. Our results showed that the synthesized PPGs had swelling percentage (
S
%) in the range of 2–1300% for different types of salt solution. Moreover, the results confirmed that the swelling amount of PPG samples has a parabolic behavior against mole ratio of AAm/AA and decreases with increasing mole percentage of MBA. |
| doi_str_mv | 10.1007/s13202-017-0428-x |
| format | article |
| fullrecord | <record><control><sourceid>proquest_doaj_</sourceid><recordid>TN_cdi_doaj_primary_oai_doaj_org_article_71d984e3f1e145589dac61f153b3b223</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><doaj_id>oai_doaj_org_article_71d984e3f1e145589dac61f153b3b223</doaj_id><sourcerecordid>1993444473</sourcerecordid><originalsourceid>FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203</originalsourceid><addsrcrecordid>eNp1kctOwzAQRSMEEhX0A9hFYh3wK4m9RBWPSpVYAGvLscetqyQudgrt3-M2qGKDN-MZn3tt62bZDUZ3GKH6PmJKECkQrgvECC92Z9mEYIEKVFbV-Wlf8stsGqNrEsRQLQidZN3bvh9WEF3Mvc1Vn4O1Tjvoh1z7jW_3HYTjiQ77VnXOQILM2DqdqjPHgYEBQud6NTjfHwRuiHn8hrZ1_TJvYKW-nA_X2YVVbYTpb73KPp4e32cvxeL1eT57WBSakXIojGW4EZyXvFFMW84aw2uGea0r0ByELROggFecK6hUQ2wlapb-J6g1mCB6lc1HX-PVWm6C61TYS6-cPA58WEoVBqdbkDU2gjOgFgM-WhilK2xxSRvaEEKT1-3otQn-cwtxkGu_DX16vsRCUJZWfaDwSOngYwxgT7diJA8hyTEkmUKSh5DkLmnIqImJ7ZcQ_jj_K_oBr5CVdg</addsrcrecordid><sourcetype>Open Website</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1993444473</pqid></control><display><type>article</type><title>Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior</title><source>Publicly Available Content Database</source><source>ABI/INFORM Global</source><source>Springer Nature - SpringerLink Journals - Fully Open Access</source><source>Free Full-Text Journals in Chemistry</source><creator>Heidari, Samira ; Esmaeilzadeh, Feridun ; Mowla, Dariush ; Ghasemi, Sohila</creator><creatorcontrib>Heidari, Samira ; Esmaeilzadeh, Feridun ; Mowla, Dariush ; Ghasemi, Sohila</creatorcontrib><description>The main purpose of this work is to prepare an efficient series of preformed particle gels (PPGs) and to study their behaviors to control unwanted water in oil fields. To this end, 12 copolymer samples composed of acrylamide and acrylic acid [poly(AAm-
co
-AA)] with different AAm/AA mole ratios and various mole percentages of
N
,
N
′-methylenebisacrylamide (MBA) were synthesized by a free radical copolymerization method. The gelation time of each sample was measured. The samples were dried in three consecutive steps: drying at atmospheric condition, drying in the oven, and drying in the vacuum oven, respectively. The chemical structure and morphology of the prepared PPGs were studied by a Fourier transform infrared spectroscopy and a scanning electron microscopy, respectively. Additionally, the swelling percentage of PPG samples was examined in different types of salt water (MgCl
2
·6H
2
O, CaCl
2
·2H
2
O, BaCl
2
·2H
2
O, NaCl, KCl, and LiCl) with 200,000 ppm concentration and pH in the range of 3–8. Our results showed that the synthesized PPGs had swelling percentage (
S
%) in the range of 2–1300% for different types of salt solution. Moreover, the results confirmed that the swelling amount of PPG samples has a parabolic behavior against mole ratio of AAm/AA and decreases with increasing mole percentage of MBA.</description><identifier>ISSN: 2190-0558</identifier><identifier>EISSN: 2190-0566</identifier><identifier>DOI: 10.1007/s13202-017-0428-x</identifier><language>eng</language><publisher>Cham: Springer International Publishing</publisher><subject>Acrylamide ; Acrylic acid ; Analytical methods ; Barium chloride ; Calcium chloride ; Chemical synthesis ; Copolymerization ; Drying ; Drying ovens ; Earth and Environmental Science ; Earth Sciences ; Electron microscopy ; Energy Systems ; Fourier transforms ; Free radical copolymerization ; Gelation ; Gelation time ; Gels ; Geology ; Industrial and Production Engineering ; Industrial Chemistry/Chemical Engineering ; Infrared spectroscopy ; Lithium chloride ; Methylene bisacrylamide ; Monitoring/Environmental Analysis ; Offshore Engineering ; Oil and gas fields ; Oil fields ; Original Paper - Production Engineering ; Polymerization ; Preformed particle gels ; Ratios ; Saline water ; Sodium chloride ; Swelling ; Swelling ratio</subject><ispartof>Journal of petroleum exploration and production technology, 2018-12, Vol.8 (4), p.1331-1340</ispartof><rights>The Author(s) 2018</rights><rights>Journal of Petroleum Exploration and Production Technology is a copyright of Springer, (2018). All Rights Reserved. © 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.</rights><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203</citedby><cites>FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://www.proquest.com/docview/1993444473/fulltextPDF?pq-origsite=primo$$EPDF$$P50$$Gproquest$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://www.proquest.com/docview/1993444473?pq-origsite=primo$$EHTML$$P50$$Gproquest$$Hfree_for_read</linktohtml><link.rule.ids>314,777,781,11669,25734,27905,27906,36041,36993,44344,44571,74644,74875</link.rule.ids></links><search><creatorcontrib>Heidari, Samira</creatorcontrib><creatorcontrib>Esmaeilzadeh, Feridun</creatorcontrib><creatorcontrib>Mowla, Dariush</creatorcontrib><creatorcontrib>Ghasemi, Sohila</creatorcontrib><title>Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior</title><title>Journal of petroleum exploration and production technology</title><addtitle>J Petrol Explor Prod Technol</addtitle><description>The main purpose of this work is to prepare an efficient series of preformed particle gels (PPGs) and to study their behaviors to control unwanted water in oil fields. To this end, 12 copolymer samples composed of acrylamide and acrylic acid [poly(AAm-
co
-AA)] with different AAm/AA mole ratios and various mole percentages of
N
,
N
′-methylenebisacrylamide (MBA) were synthesized by a free radical copolymerization method. The gelation time of each sample was measured. The samples were dried in three consecutive steps: drying at atmospheric condition, drying in the oven, and drying in the vacuum oven, respectively. The chemical structure and morphology of the prepared PPGs were studied by a Fourier transform infrared spectroscopy and a scanning electron microscopy, respectively. Additionally, the swelling percentage of PPG samples was examined in different types of salt water (MgCl
2
·6H
2
O, CaCl
2
·2H
2
O, BaCl
2
·2H
2
O, NaCl, KCl, and LiCl) with 200,000 ppm concentration and pH in the range of 3–8. Our results showed that the synthesized PPGs had swelling percentage (
S
%) in the range of 2–1300% for different types of salt solution. Moreover, the results confirmed that the swelling amount of PPG samples has a parabolic behavior against mole ratio of AAm/AA and decreases with increasing mole percentage of MBA.</description><subject>Acrylamide</subject><subject>Acrylic acid</subject><subject>Analytical methods</subject><subject>Barium chloride</subject><subject>Calcium chloride</subject><subject>Chemical synthesis</subject><subject>Copolymerization</subject><subject>Drying</subject><subject>Drying ovens</subject><subject>Earth and Environmental Science</subject><subject>Earth Sciences</subject><subject>Electron microscopy</subject><subject>Energy Systems</subject><subject>Fourier transforms</subject><subject>Free radical copolymerization</subject><subject>Gelation</subject><subject>Gelation time</subject><subject>Gels</subject><subject>Geology</subject><subject>Industrial and Production Engineering</subject><subject>Industrial Chemistry/Chemical Engineering</subject><subject>Infrared spectroscopy</subject><subject>Lithium chloride</subject><subject>Methylene bisacrylamide</subject><subject>Monitoring/Environmental Analysis</subject><subject>Offshore Engineering</subject><subject>Oil and gas fields</subject><subject>Oil fields</subject><subject>Original Paper - Production Engineering</subject><subject>Polymerization</subject><subject>Preformed particle gels</subject><subject>Ratios</subject><subject>Saline water</subject><subject>Sodium chloride</subject><subject>Swelling</subject><subject>Swelling ratio</subject><issn>2190-0558</issn><issn>2190-0566</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2018</creationdate><recordtype>article</recordtype><sourceid>M0C</sourceid><sourceid>PIMPY</sourceid><sourceid>DOA</sourceid><recordid>eNp1kctOwzAQRSMEEhX0A9hFYh3wK4m9RBWPSpVYAGvLscetqyQudgrt3-M2qGKDN-MZn3tt62bZDUZ3GKH6PmJKECkQrgvECC92Z9mEYIEKVFbV-Wlf8stsGqNrEsRQLQidZN3bvh9WEF3Mvc1Vn4O1Tjvoh1z7jW_3HYTjiQ77VnXOQILM2DqdqjPHgYEBQud6NTjfHwRuiHn8hrZ1_TJvYKW-nA_X2YVVbYTpb73KPp4e32cvxeL1eT57WBSakXIojGW4EZyXvFFMW84aw2uGea0r0ByELROggFecK6hUQ2wlapb-J6g1mCB6lc1HX-PVWm6C61TYS6-cPA58WEoVBqdbkDU2gjOgFgM-WhilK2xxSRvaEEKT1-3otQn-cwtxkGu_DX16vsRCUJZWfaDwSOngYwxgT7diJA8hyTEkmUKSh5DkLmnIqImJ7ZcQ_jj_K_oBr5CVdg</recordid><startdate>20181201</startdate><enddate>20181201</enddate><creator>Heidari, Samira</creator><creator>Esmaeilzadeh, Feridun</creator><creator>Mowla, Dariush</creator><creator>Ghasemi, Sohila</creator><general>Springer International Publishing</general><general>Springer Nature B.V</general><general>SpringerOpen</general><scope>C6C</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>3V.</scope><scope>7TN</scope><scope>7WY</scope><scope>7WZ</scope><scope>7XB</scope><scope>87Z</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FK</scope><scope>8FL</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AEUYN</scope><scope>AFKRA</scope><scope>AZQEC</scope><scope>BENPR</scope><scope>BEZIV</scope><scope>BGLVJ</scope><scope>BHPHI</scope><scope>BKSAR</scope><scope>CCPQU</scope><scope>DWQXO</scope><scope>F1W</scope><scope>FR3</scope><scope>FRNLG</scope><scope>F~G</scope><scope>H96</scope><scope>HCIFZ</scope><scope>K60</scope><scope>K6~</scope><scope>KR7</scope><scope>L.-</scope><scope>L.G</scope><scope>L6V</scope><scope>M0C</scope><scope>M7S</scope><scope>PCBAR</scope><scope>PIMPY</scope><scope>PQBIZ</scope><scope>PQBZA</scope><scope>PQEST</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PTHSS</scope><scope>Q9U</scope><scope>DOA</scope></search><sort><creationdate>20181201</creationdate><title>Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior</title><author>Heidari, Samira ; Esmaeilzadeh, Feridun ; Mowla, Dariush ; Ghasemi, Sohila</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2018</creationdate><topic>Acrylamide</topic><topic>Acrylic acid</topic><topic>Analytical methods</topic><topic>Barium chloride</topic><topic>Calcium chloride</topic><topic>Chemical synthesis</topic><topic>Copolymerization</topic><topic>Drying</topic><topic>Drying ovens</topic><topic>Earth and Environmental Science</topic><topic>Earth Sciences</topic><topic>Electron microscopy</topic><topic>Energy Systems</topic><topic>Fourier transforms</topic><topic>Free radical copolymerization</topic><topic>Gelation</topic><topic>Gelation time</topic><topic>Gels</topic><topic>Geology</topic><topic>Industrial and Production Engineering</topic><topic>Industrial Chemistry/Chemical Engineering</topic><topic>Infrared spectroscopy</topic><topic>Lithium chloride</topic><topic>Methylene bisacrylamide</topic><topic>Monitoring/Environmental Analysis</topic><topic>Offshore Engineering</topic><topic>Oil and gas fields</topic><topic>Oil fields</topic><topic>Original Paper - Production Engineering</topic><topic>Polymerization</topic><topic>Preformed particle gels</topic><topic>Ratios</topic><topic>Saline water</topic><topic>Sodium chloride</topic><topic>Swelling</topic><topic>Swelling ratio</topic><toplevel>online_resources</toplevel><creatorcontrib>Heidari, Samira</creatorcontrib><creatorcontrib>Esmaeilzadeh, Feridun</creatorcontrib><creatorcontrib>Mowla, Dariush</creatorcontrib><creatorcontrib>Ghasemi, Sohila</creatorcontrib><collection>SpringerOpen</collection><collection>CrossRef</collection><collection>ProQuest Central (Corporate)</collection><collection>Oceanic Abstracts</collection><collection>ABI/INFORM Collection</collection><collection>ABI/INFORM Global (PDF only)</collection><collection>ProQuest Central (purchase pre-March 2016)</collection><collection>ABI/INFORM Global (Alumni Edition)</collection><collection>Technology Research Database</collection><collection>ProQuest SciTech Collection</collection><collection>ProQuest Technology Collection</collection><collection>ProQuest Central (Alumni) (purchase pre-March 2016)</collection><collection>ABI/INFORM Collection (Alumni Edition)</collection><collection>Materials Science & Engineering Collection</collection><collection>ProQuest Central (Alumni)</collection><collection>ProQuest One Sustainability</collection><collection>ProQuest Central</collection><collection>ProQuest Central Essentials</collection><collection>ProQuest Central</collection><collection>Business Premium Collection</collection><collection>Technology Collection</collection><collection>Natural Science Collection</collection><collection>Earth, Atmospheric & Aquatic Science Collection</collection><collection>ProQuest One Community College</collection><collection>ProQuest Central Korea</collection><collection>ASFA: Aquatic Sciences and Fisheries Abstracts</collection><collection>Engineering Research Database</collection><collection>Business Premium Collection (Alumni)</collection><collection>ABI/INFORM Global (Corporate)</collection><collection>Aquatic Science & Fisheries Abstracts (ASFA) 2: Ocean Technology, Policy & Non-Living Resources</collection><collection>SciTech Premium Collection</collection><collection>ProQuest Business Collection (Alumni Edition)</collection><collection>ProQuest Business Collection</collection><collection>Civil Engineering Abstracts</collection><collection>ABI/INFORM Professional Advanced</collection><collection>Aquatic Science & Fisheries Abstracts (ASFA) Professional</collection><collection>ProQuest Engineering Collection</collection><collection>ABI/INFORM Global</collection><collection>Engineering Database</collection><collection>Earth, Atmospheric & Aquatic Science Database</collection><collection>Publicly Available Content Database</collection><collection>One Business</collection><collection>ProQuest One Business (Alumni)</collection><collection>ProQuest One Academic Eastern Edition (DO NOT USE)</collection><collection>ProQuest One Academic</collection><collection>ProQuest One Academic UKI Edition</collection><collection>Engineering Collection</collection><collection>ProQuest Central Basic</collection><collection>DOAJ Directory of Open Access Journals</collection><jtitle>Journal of petroleum exploration and production technology</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Heidari, Samira</au><au>Esmaeilzadeh, Feridun</au><au>Mowla, Dariush</au><au>Ghasemi, Sohila</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior</atitle><jtitle>Journal of petroleum exploration and production technology</jtitle><stitle>J Petrol Explor Prod Technol</stitle><date>2018-12-01</date><risdate>2018</risdate><volume>8</volume><issue>4</issue><spage>1331</spage><epage>1340</epage><pages>1331-1340</pages><issn>2190-0558</issn><eissn>2190-0566</eissn><abstract>The main purpose of this work is to prepare an efficient series of preformed particle gels (PPGs) and to study their behaviors to control unwanted water in oil fields. To this end, 12 copolymer samples composed of acrylamide and acrylic acid [poly(AAm-
co
-AA)] with different AAm/AA mole ratios and various mole percentages of
N
,
N
′-methylenebisacrylamide (MBA) were synthesized by a free radical copolymerization method. The gelation time of each sample was measured. The samples were dried in three consecutive steps: drying at atmospheric condition, drying in the oven, and drying in the vacuum oven, respectively. The chemical structure and morphology of the prepared PPGs were studied by a Fourier transform infrared spectroscopy and a scanning electron microscopy, respectively. Additionally, the swelling percentage of PPG samples was examined in different types of salt water (MgCl
2
·6H
2
O, CaCl
2
·2H
2
O, BaCl
2
·2H
2
O, NaCl, KCl, and LiCl) with 200,000 ppm concentration and pH in the range of 3–8. Our results showed that the synthesized PPGs had swelling percentage (
S
%) in the range of 2–1300% for different types of salt solution. Moreover, the results confirmed that the swelling amount of PPG samples has a parabolic behavior against mole ratio of AAm/AA and decreases with increasing mole percentage of MBA.</abstract><cop>Cham</cop><pub>Springer International Publishing</pub><doi>10.1007/s13202-017-0428-x</doi><tpages>10</tpages><oa>free_for_read</oa></addata></record> |
| fulltext | fulltext |
| identifier | ISSN: 2190-0558 |
| ispartof | Journal of petroleum exploration and production technology, 2018-12, Vol.8 (4), p.1331-1340 |
| issn | 2190-0558 2190-0566 |
| language | eng |
| recordid | cdi_doaj_primary_oai_doaj_org_article_71d984e3f1e145589dac61f153b3b223 |
| source | Publicly Available Content Database; ABI/INFORM Global; Springer Nature - SpringerLink Journals - Fully Open Access; Free Full-Text Journals in Chemistry |
| subjects | Acrylamide Acrylic acid Analytical methods Barium chloride Calcium chloride Chemical synthesis Copolymerization Drying Drying ovens Earth and Environmental Science Earth Sciences Electron microscopy Energy Systems Fourier transforms Free radical copolymerization Gelation Gelation time Gels Geology Industrial and Production Engineering Industrial Chemistry/Chemical Engineering Infrared spectroscopy Lithium chloride Methylene bisacrylamide Monitoring/Environmental Analysis Offshore Engineering Oil and gas fields Oil fields Original Paper - Production Engineering Polymerization Preformed particle gels Ratios Saline water Sodium chloride Swelling Swelling ratio |
| title | Synthesis of an efficient copolymer of acrylamide and acrylic acid and determination of its swelling behavior |
| url | http://sfxeu10.hosted.exlibrisgroup.com/loughborough?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-18T21%3A43%3A46IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_doaj_&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Synthesis%20of%20an%20efficient%20copolymer%20of%20acrylamide%20and%20acrylic%20acid%20and%20determination%20of%20its%20swelling%20behavior&rft.jtitle=Journal%20of%20petroleum%20exploration%20and%20production%20technology&rft.au=Heidari,%20Samira&rft.date=2018-12-01&rft.volume=8&rft.issue=4&rft.spage=1331&rft.epage=1340&rft.pages=1331-1340&rft.issn=2190-0558&rft.eissn=2190-0566&rft_id=info:doi/10.1007/s13202-017-0428-x&rft_dat=%3Cproquest_doaj_%3E1993444473%3C/proquest_doaj_%3E%3Cgrp_id%3Ecdi_FETCH-LOGICAL-c425t-df41b98858ba4cf84bd874187c6ec8e9f5f41ae8688ae6ab2f697455893fd1203%3C/grp_id%3E%3Coa%3E%3C/oa%3E%3Curl%3E%3C/url%3E&rft_id=info:oai/&rft_pqid=1993444473&rft_id=info:pmid/&rfr_iscdi=true |