4 DiscussionWhile a significantly b

4 Discussion

While a significantly broader resin code identification system has the potential to revolutionize recycling in the U.S., due to current policies and institutional structures within ASTM through the D20.95.01 SPI Resin Code Section, such a system is unlikely to be accepted in the near future (Pecorini, 2014). Part of this is simply inertia, as the ASTM standards are determined by consensus of all the members of the task group, which is made up of volunteer stake holders. Consider the only recent change made to the U.S. code is to change the symbol from chasing arrows (denoting recycling) to a simple equilateral triangle, which was made to avoid ‘consumer confusion’ as recycling of all the recyclable plastics is not available in all municipalities. For those concerned about fostering sustainable behavior in consumers this would be appear to be step backward (McKenzie-Mohr, 2013). Similarly, pro-recycling laws can have unintended consequences. For example, California's Electronic Waste Recycling Act of 2003, which levies different fees on electronic devices or screens depending on the recyclability and size of the object (California State Board of Equalization, 2004), provides a disincentive to firms producing any polymer without a code to adopt one. The ASTM task group is discussing adding extra identification by adding extensions to the numbers, to help recyclers better identify what is in the plastic. However, the change is unlikely to take place as some members feel adding any additional information to the existing U.S. code is unnecessary because the main six resins account for 3/4 of plastic waste (SPI, 2014 and Spevacek, 2014) and such a small percentage of that is currently recycled. This thinking is predicated on a centralized recycling model, which currently dominates polymer recycling in the U.S. However, with the growth of distributed 3-D printing for manufacturing, in the future the plastic waste produced will no longer necessarily continue to be limited these six resins as the new developed filaments range widely in materials. The number of registered 3D-printers to 3D Hubs grew 2,100% from last year alone (Sher, 2014b). This growth coupled with the decrease in cost per consumer objects is dropping by as much as 35% in some categories shows the growth is occurring now (Sher, 2014b).

This distributed production of more complex materials is complimented by the development of recyclebots, including the proprietary commercial, open-source and DIY varieties. Because the recycling as well as manufacturing can now be located in the home, at a local business, or community center, the prosumer needs to know what they can use and what is not compatible with their machines. Currently due to the relatively low-reliability of the 3-D printers (some studies estimate 20% failure (Wittbrodt et al., 2013)), prints do not always work the first time, and thus there is a large source of reusable scrap plastic associated with most FFF 3-D printers. Being able to reuse these failed prints or use waste plastic to make additional filament is very cost effective for the prosumer (Baechler et al., 2013). There are organizations such as The Plastic Bank (The Plastic Bank, 2014), Ethical Filament Foundation (Ethical Filament Foundation, 2014), and the Perpetual Plastics Project (Project, 2014) that are dedicated to waste plastic recycling for 3-D recycled filament. Recycling has been proven to have lower environmental impact than incineration and landfilling, and while various methods have varying results increased use of recycled plastic is expected impact the environment positively (Rajendran et al., 2012, Björklund and Finnveden, 2005 and Chilton et al., 2010). In addition, distributed recycling has been shown to be able to reduce the environmental impact of plastic from conventional recycling (Kreiger and Pearce, 2013a). Thus, the easier it is to identify and recycle plastics using these distributed methods, the better it will be for the environment.

While this code system is a significant improvement over the current resin identification system, there is room for even greater improvement. Incorporating the symbol directly into the open-source slicer programs like Cura (Cura, 2013), Slic3r (Slic3r, 2014), and Skeinforge (Skeinforge, 2012), will increase the ease the symbol can be set into 3-D models. Instead of creating the model with the symbol in it, the symbol can be generated while slicing the model into g-code, all that is needed are variables to indicate the symbol, polymer, and any extra substances the filament contains. Building off of the work here as shown in Fig. 4, it would be possible to make the infill be the recycling symbol itself. A few widely used plastics could have a preset and the prosumer could create their own saved symbol for plastics they use often. These presets could be identified by a quick response (QR) code on the packages of new filament so the prosumer could avoid inputting them manually. Once the variables or preset symbols are selected all the user would need to do is select whether the symbol should be on the outside or inside, if outside then if it is to be raised or indented, how far it should be raised or indented, what size, and where on the model it should be placed. This can all be done with the current code manually in OpenSCAD, before the STL is created, which is acceptable for designers, but not everyday prosumers.

Future work is needed to adapt some of the other functions of the Chinese resin identification code to the system provided here is the function of the various plastics (e.g., anti-bacterial, high impedance, bio-degradable, etc.). In order for this to be integrated into the symbol a code must be created to identify the function(s) of the plastic and unfortunately the Chinese system is not differentiated highly enough for this application now. Printing out all of the words, especially if the polymer has multiple functions, would make the words hard to read. If the symbol is smaller then the words would be indistinguishable, even with high-resolution printers. A simple letter, number, or abbreviation code would solve this issue, just like the polymer have their own specific abbreviations as shown in Appendix 1. This extra feature to the symbol would also help prosumers with a specific purpose for their products to find a specific plastic to re-use or see what can not be used.

The voluntary recycling protocols developed here have become more relevant to future recycling policy due in part to China's application of the Green Fence Policy established in February 2013. China imports about 70% of the worlds 12 milliont of plastic waste every year (Taylor, 2014). The Green Fence Policy restricts the amount of contaminant in waste bales to 1.5% or lower, which resulted in the rejection of over 800,000 t of recyclables or scrap (Earley, 2013). This change raised the cost of recycling for U.S. companies and while many companies supported this ecological policy shift, many simply shifted waste exports to other countries such as Turkey or Vietnam on economic grounds (Margolis, 2014). This policy change shocked the industry and showed that the main issue with North American recycling is the need for better quality control (ASTM International, 2014).

The recycling code system developed here is a voluntary system for which prosumers will implement for their own benefit. Thus, it avoids the challenges associated with exporting waste plastic internationally. Although, the estimated sales of personal 3D printers from 2007 to 2011 was 346% each year (Wohlers Associates, 2014), today the total prosumer plastic waste is still a tiny fraction of a percent of the U.S. whole. Until distributed production and recycling have become the norm, improvements are needed in the U.S. system. In order for the sum total of U.S. recyclable plastic waste to be recycled, particularly in the short term, the U.S. resin code must be expanded and adopted by the plastic industry as a whole. For this to happen legislation is needed to make it mandatory at the national level, as unlike the prosumer-based system investigated here (where recycling by being in line with the prosumer's economic interest), the centralized system externalizes costs to such an extent that the economic incentive is lost. Currently, the recycling code in the U.S. is changed and regulated by the ASTM, a non-profit private organization that focuses on developing international standards (ASTM International, 2014). In order to expedite this change the responsibilities of expanding the codes and regulations on recycling should be investigated by government at the national level, similar to the policy implementations in China (E.C. Director, 2014). By enabling the government to regulate recycling codes, the market can operate more efficiently as full costs will be accounted for in transactions, and economic incentives can be aligned with the benefits to the environment and the rest of society.

ผลลัพธ์ (ไทย) 1:

สนทนา 4While a significantly broader resin code identification system has the potential to revolutionize recycling in the U.S., due to current policies and institutional structures within ASTM through the D20.95.01 SPI Resin Code Section, such a system is unlikely to be accepted in the near future (Pecorini, 2014). Part of this is simply inertia, as the ASTM standards are determined by consensus of all the members of the task group, which is made up of volunteer stake holders. Consider the only recent change made to the U.S. code is to change the symbol from chasing arrows (denoting recycling) to a simple equilateral triangle, which was made to avoid ‘consumer confusion’ as recycling of all the recyclable plastics is not available in all municipalities. For those concerned about fostering sustainable behavior in consumers this would be appear to be step backward (McKenzie-Mohr, 2013). Similarly, pro-recycling laws can have unintended consequences. For example, California's Electronic Waste Recycling Act of 2003, which levies different fees on electronic devices or screens depending on the recyclability and size of the object (California State Board of Equalization, 2004), provides a disincentive to firms producing any polymer without a code to adopt one. The ASTM task group is discussing adding extra identification by adding extensions to the numbers, to help recyclers better identify what is in the plastic. However, the change is unlikely to take place as some members feel adding any additional information to the existing U.S. code is unnecessary because the main six resins account for 3/4 of plastic waste (SPI, 2014 and Spevacek, 2014) and such a small percentage of that is currently recycled. This thinking is predicated on a centralized recycling model, which currently dominates polymer recycling in the U.S. However, with the growth of distributed 3-D printing for manufacturing, in the future the plastic waste produced will no longer necessarily continue to be limited these six resins as the new developed filaments range widely in materials. The number of registered 3D-printers to 3D Hubs grew 2,100% from last year alone (Sher, 2014b). This growth coupled with the decrease in cost per consumer objects is dropping by as much as 35% in some categories shows the growth is occurring now (Sher, 2014b).This distributed production of more complex materials is complimented by the development of recyclebots, including the proprietary commercial, open-source and DIY varieties. Because the recycling as well as manufacturing can now be located in the home, at a local business, or community center, the prosumer needs to know what they can use and what is not compatible with their machines. Currently due to the relatively low-reliability of the 3-D printers (some studies estimate 20% failure (Wittbrodt et al., 2013)), prints do not always work the first time, and thus there is a large source of reusable scrap plastic associated with most FFF 3-D printers. Being able to reuse these failed prints or use waste plastic to make additional filament is very cost effective for the prosumer (Baechler et al., 2013). There are organizations such as The Plastic Bank (The Plastic Bank, 2014), Ethical Filament Foundation (Ethical Filament Foundation, 2014), and the Perpetual Plastics Project (Project, 2014) that are dedicated to waste plastic recycling for 3-D recycled filament. Recycling has been proven to have lower environmental impact than incineration and landfilling, and while various methods have varying results increased use of recycled plastic is expected impact the environment positively (Rajendran et al., 2012, Björklund and Finnveden, 2005 and Chilton et al., 2010). In addition, distributed recycling has been shown to be able to reduce the environmental impact of plastic from conventional recycling (Kreiger and Pearce, 2013a). Thus, the easier it is to identify and recycle plastics using these distributed methods, the better it will be for the environment.While this code system is a significant improvement over the current resin identification system, there is room for even greater improvement. Incorporating the symbol directly into the open-source slicer programs like Cura (Cura, 2013), Slic3r (Slic3r, 2014), and Skeinforge (Skeinforge, 2012), will increase the ease the symbol can be set into 3-D models. Instead of creating the model with the symbol in it, the symbol can be generated while slicing the model into g-code, all that is needed are variables to indicate the symbol, polymer, and any extra substances the filament contains. Building off of the work here as shown in Fig. 4, it would be possible to make the infill be the recycling symbol itself. A few widely used plastics could have a preset and the prosumer could create their own saved symbol for plastics they use often. These presets could be identified by a quick response (QR) code on the packages of new filament so the prosumer could avoid inputting them manually. Once the variables or preset symbols are selected all the user would need to do is select whether the symbol should be on the outside or inside, if outside then if it is to be raised or indented, how far it should be raised or indented, what size, and where on the model it should be placed. This can all be done with the current code manually in OpenSCAD, before the STL is created, which is acceptable for designers, but not everyday prosumers.Future work is needed to adapt some of the other functions of the Chinese resin identification code to the system provided here is the function of the various plastics (e.g., anti-bacterial, high impedance, bio-degradable, etc.). In order for this to be integrated into the symbol a code must be created to identify the function(s) of the plastic and unfortunately the Chinese system is not differentiated highly enough for this application now. Printing out all of the words, especially if the polymer has multiple functions, would make the words hard to read. If the symbol is smaller then the words would be indistinguishable, even with high-resolution printers. A simple letter, number, or abbreviation code would solve this issue, just like the polymer have their own specific abbreviations as shown in Appendix 1. This extra feature to the symbol would also help prosumers with a specific purpose for their products to find a specific plastic to re-use or see what can not be used.The voluntary recycling protocols developed here have become more relevant to future recycling policy due in part to China's application of the Green Fence Policy established in February 2013. China imports about 70% of the worlds 12 milliont of plastic waste every year (Taylor, 2014). The Green Fence Policy restricts the amount of contaminant in waste bales to 1.5% or lower, which resulted in the rejection of over 800,000 t of recyclables or scrap (Earley, 2013). This change raised the cost of recycling for U.S. companies and while many companies supported this ecological policy shift, many simply shifted waste exports to other countries such as Turkey or Vietnam on economic grounds (Margolis, 2014). This policy change shocked the industry and showed that the main issue with North American recycling is the need for better quality control (ASTM International, 2014).
The recycling code system developed here is a voluntary system for which prosumers will implement for their own benefit. Thus, it avoids the challenges associated with exporting waste plastic internationally. Although, the estimated sales of personal 3D printers from 2007 to 2011 was 346% each year (Wohlers Associates, 2014), today the total prosumer plastic waste is still a tiny fraction of a percent of the U.S. whole. Until distributed production and recycling have become the norm, improvements are needed in the U.S. system. In order for the sum total of U.S. recyclable plastic waste to be recycled, particularly in the short term, the U.S. resin code must be expanded and adopted by the plastic industry as a whole. For this to happen legislation is needed to make it mandatory at the national level, as unlike the prosumer-based system investigated here (where recycling by being in line with the prosumer's economic interest), the centralized system externalizes costs to such an extent that the economic incentive is lost. Currently, the recycling code in the U.S. is changed and regulated by the ASTM, a non-profit private organization that focuses on developing international standards (ASTM International, 2014). In order to expedite this change the responsibilities of expanding the codes and regulations on recycling should be investigated by government at the national level, similar to the policy implementations in China (E.C. Director, 2014). By enabling the government to regulate recycling codes, the market can operate more efficiently as full costs will be accounted for in transactions, and economic incentives can be aligned with the benefits to the environment and the rest of society.

ผลลัพธ์ (ไทย) 3:

4 สนทนา

ในขณะที่ความกว้างรหัสเรซิ่นตัวระบบมีศักยภาพที่จะปฏิวัติการรีไซเคิลในสหรัฐอเมริกา เนื่องจากนโยบายปัจจุบันและโครงสร้างสถาบันภายใน ASTM ผ่าน d20.95.01 SPI เรซินรหัส ส่วน ระบบดังกล่าวไม่น่าจะยอมรับในอนาคตอันใกล้ ( pecorini 2014 ) นี้เป็นเพียงส่วนหนึ่งของความเฉื่อยเป็นมาตรฐาน ASTM มาตรฐานจะถูกกำหนดโดยมติของสมาชิกทั้งหมดของกลุ่มงาน ซึ่งถูกสร้างขึ้นจากผู้ถือหุ้นอาสาสมัคร พิจารณาเฉพาะล่าสุดเปลี่ยนให้สหรัฐอเมริการหัสคือการเปลี่ยนสัญลักษณ์จากไล่ตามลูกศร ( denoting รีไซเคิล ) สามเหลี่ยมของปาสกาลอย่างง่ายซึ่งทำขึ้นเพื่อหลีกเลี่ยงความสับสน ' ' ผู้บริโภครีไซเคิลพลาสติกรีไซเคิลทั้งหมดไม่สามารถใช้ได้ในทุกเทศบาล สำหรับผู้ที่กังวลเกี่ยวกับการสร้างที่ยั่งยืนพฤติกรรมผู้บริโภคนี้จะปรากฏเป็นขั้นตอนย้อนกลับ ( McKenzie Mohr , 2013 ) ในทำนองเดียวกัน , Pro รีไซเคิลกฎหมายจะมีผลที่ไม่ตั้งใจ ตัวอย่างเช่นรัฐแคลิฟอร์เนียเป็นขยะอิเล็กทรอนิกส์รีไซเคิล Act of 2003 ,ซึ่งภาษี ค่าธรรมเนียมต่าง ๆ บนอุปกรณ์อิเล็กทรอนิกส์ หรือ หน้าจอใหม่ และขึ้นอยู่กับขนาดของวัตถุ ( แคลิฟอร์เนียรัฐคณะกรรมการอีค , 2004 ) , บริษัท ผลิตใด ๆให้ disincentive พอลิเมอร์ที่ไม่มีรหัสรับหนึ่ง กลุ่มงานมาตรฐาน ASTM คือการเพิ่มตัวเสริมโดยการเพิ่มส่วนขยายไปยังหมายเลขเพื่อช่วยในการรีไซเคิลที่ดีระบุว่าอยู่ในพลาสติก อย่างไรก็ตาม การเปลี่ยนแปลงเป็นเรื่องที่ไม่น่าเกิดขึ้นขณะที่สมาชิกบางคนรู้สึกเพิ่มข้อมูลใด ๆเพิ่มเติมเพื่อที่มีอยู่ของสหรัฐอเมริการหัสไม่จำเป็นเนื่องจากบัญชี 6 เม็ดหลัก 3 / 4 ของขยะพลาสติก ( SPI ) และ spevacek 2014 2014 ) และร้อยละขนาดเล็กของที่ขณะนี้รีไซเคิล