We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the...We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the first author's previous works on this topic.展开更多
This paper describes the researching aim and content of Ergonomics.Some prob-lems existing in modern harvesting system,such as machinery availability,cabin design,occupational accident,noise and vibration are discusse...This paper describes the researching aim and content of Ergonomics.Some prob-lems existing in modern harvesting system,such as machinery availability,cabin design,occupational accident,noise and vibration are discussed from the viewpoint of Ergonomics.Furthermore,some improving ways and suggestions are presented.展开更多
An empirical time study was cohducted to evaluate the performance of the current felling and tree processing methods used in Northern Iran＇s Hyrcanian forest. Motor-manual felling is done mostly in winter, while tree...An empirical time study was cohducted to evaluate the performance of the current felling and tree processing methods used in Northern Iran＇s Hyrcanian forest. Motor-manual felling is done mostly in winter, while tree processing starts when the felling season ends. We identified the elements of felling and processing work phases, and 142 cycles and 110 cycles were respectively recorded for felling and processing. On the basis of data analysis （time study）, we developed statistical models of effective time consumption in the respective work phase and for its total productivity. The production rate of felling with and without delay time was 9.7 and 11.65 trees per hour （0.17 USD.m^-3 and 0.21 USD-m^-3）, and the average production cost with and without delay was 1.21 USD and 1.45 USD per tree, respectively. The average productivity of processing was 35 m^3 per effective hour and the average unit cost of processing was 0.92 USD.m^-3.展开更多
Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region....Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region. The selective cutting was performed on a 42-ha tract with an average slope of 30%. The results indicate that felling time for per tree is most affected by diameter at breast height, the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method. The production rate in single and group selection cutting were 21.2 m^3·h^-1 and 28.4 m^3·h^-1 for one person, respectively. Considering the gross and net production rate in single and group selection cutting, the unit cost was 1.11 USD.m^-3 and 0.88 USD.m^-3, respectively. The results indicate that group selection cutting can be more profitable than single-tree selection method.展开更多
Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following phases.In this research, in order to examine the reducti...Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following phases.In this research, in order to examine the reduction of costs with respect to present and planned operations, the starting time of the harvesting or cutting phase and work flow were recorded. The starting time of each phase of the entire operation was recorded as well. Before harvesting the marked tree, the appropriate felling direction was determined and the azimuth of the correct direction was taken.The results indicate that there was not a meaningful relationship between the differences in direction of a leaning tree compared with the felling direction. However, there was a significant relationship between the difference of the defined and felling direction and the difference in tree leaning and defined direction. The same trend was observed between tree leaning and felling directions and tree leaning and defined directions. On the other hand,there was no significant relationship between tree leaning and felling directions and the defined and tree felling directions. In addition, this research shows that with an increase in tree volume, the time for tree cutting rose.Furthermore, when the difference of tree leaning and felling direction decreased, the time to cut the tree declined.The regression equation is Y = 168.9–0.14（the difference between tree leaning and felling direction） ＋ 0.7（volume）.展开更多
The cause of stop marks of fabrics in weaving is introduced, and the floating displacement of the cloth fell during loom stoppage is a primary cause of stop marks. The stop marks caused by fabric system are analyzed. ...The cause of stop marks of fabrics in weaving is introduced, and the floating displacement of the cloth fell during loom stoppage is a primary cause of stop marks. The stop marks caused by fabric system are analyzed. A new method to eliminate stop marks by using the electronic let-off system is presented. This new method needn't any special detecting equipment, it can control the fell position by the powerful control program,so the cost is decreased greatly. The method is so flexible that can be applied to weaving all kinds of fabrics.展开更多
The study evaluated the productivity and energy balance of the harvesting and the extraction of wood in plantation of exotic tree species, i.e., Pinus patula （Schiede ex Schlectendahl et Chamisso） and Cupressus lusi...The study evaluated the productivity and energy balance of the harvesting and the extraction of wood in plantation of exotic tree species, i.e., Pinus patula （Schiede ex Schlectendahl et Chamisso） and Cupressus lusitanica （Mill.）. The harvesting and extraction operations concerned clear-cut felling on two different types of terrain （gentle and steep terrain） and two levels of prun- ing. The results show that cutting is not affected by the terrain gradient whereas the pruning condition shows a significant effect on the delimbing operation. The productivity of cutting is evaluated at 28.1 m3.d-1 for unpruned trees and at 30.2 m3.d t for pruned trees. For the extraction phase, rolling was significantly affected by terrain conditions. On steep terrain, the gross productivity can be evaluated at 22.5 m3.d 1 for an extraction distance of 40 m, while for the same distance on gentle terrain the productivity decreases to 14.1 m3.d~. As a result, the steep terrain condition showed higher energy efficiency, suggesting that it is the more efficient system of extraction. The productivity model and the energy balance resulting from the study provide a better understanding of the variables af- fecting motor-manual cutting and rolling extraction in exotic plantations in Uganda.展开更多
In the afternoon of October 29th,2014,Ordifen Cup 2014 China Lingerie Design Contest unveiled during China Fashion Week.Jointly held by China Fashion Association and Ordifen International Group,the contest presented u...In the afternoon of October 29th,2014,Ordifen Cup 2014 China Lingerie Design Contest unveiled during China Fashion Week.Jointly held by China Fashion Association and Ordifen International Group,the contest presented us a grand feast with the essence of Ordifen’s ten years dedication.Tiny but delicate,the lingerie condenses the charisma of both culture and fashion in the small piece of cloth.Time goes so fast all in the blink of an eye.展开更多
Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we mo...Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we modelled how changes in the minimum felling diameter affect stem density, basal area and the related carbon biomass at the end of the felling cycle （30 years） in a semi-deciduous natural forest in Cameroon. With new MFDs estimates, at 7% logging damage rate, we found that the stem density of initially harvestable trees reduces from 12.3 （50.4 MgC·ha^-1） to 6.7 （32.5 MgC·ha^-1） trees per ha and the number of initial residual trees increases from 80 （18.9MgC·ha^-1） to 85.7 （36.8 MgC·ha^-1） trees per ha. This corresponds to an avoided damage estimated at 17.9 MgC·ha^-1. We also found that increasing mortality and damage intensity also increases the damage on carbon biomass estimated to be 8.9 MgC·ha^-1 at 10% or to be 17.4 MgC.hal at 15% logging damage. Overall, our study shows that proper determination of MFD of logged species taking into consideration their capacity of reconstitution and the Reduced Impact Logging can avoid the loss of up to 35 MgC·ha^-1.展开更多
(1) Rare earth price index Rare earth price index increased at first but fell during the end of December 2016. It grew from 115.3 to the highest of 118.5 and then fell to 116.8 at the month end. (2) Yttrium-medium and...(1) Rare earth price index Rare earth price index increased at first but fell during the end of December 2016. It grew from 115.3 to the highest of 118.5 and then fell to 116.8 at the month end. (2) Yttrium-medium and europium-rich mineral Listed price of yttrium-medium and europium-rich minerals averaged 195,000 yuan/ton in November, maintaining flat since the beginning of 2016. However, the real deal price was far lower than the listed one.展开更多
China’s rare earth export volume fell in January Analysis of customs statistics showed that China’s rare earth export volume continued to fall in January2019.Compared with January 2018, export volume fell by 1.7 per...China’s rare earth export volume fell in January Analysis of customs statistics showed that China’s rare earth export volume continued to fall in January2019.Compared with January 2018, export volume fell by 1.7 percent to 3752.9 tons, while average export prices rose by 6.0percent to$9.8/kg.展开更多
China ramps up its efforts to safeguard juveniles from the Internet gaming addiction Just before this year’s national college entrance exam,or the gaokao,on June 7-8,a letter from a despairing mother of student made ...China ramps up its efforts to safeguard juveniles from the Internet gaming addiction Just before this year’s national college entrance exam,or the gaokao,on June 7-8,a letter from a despairing mother of student made a big splash on Weibo,a Chinese Twitter-like microblogging platform.The mother described how her son,who used to be an outstanding learner,failed the exam展开更多
The Furniture Society is a member-based nonprofit organization founded in 1996.Its mission is to advance the art of furniture making by inspiring creativity,promoting excellence and fostering an understanding of this ...The Furniture Society is a member-based nonprofit organization founded in 1996.Its mission is to advance the art of furniture making by inspiring creativity,promoting excellence and fostering an understanding of this art and its place in society.By sponsoring a variety of programs that contribute to the education and enrichment of members and the public,the Furniture Society champions excel-lence,refinement,responsibility,and craftsmanship in furniture.It seems that when it comes to woodworking and working with our hands,we are inherently more connected to nature than many other occupations.I attend the Furniture Society’s annual conference every year in June.In almost every furniture maker presentation that I’ve listened to,the artist has mentioned nature as a source of inspiration.And in most encounters with fellow makers,I find that the lot genuinely tries to do good by our planet and its limited resources.Of course,the level of awareness varies among each maker,but consciousness of how we’re using resources seems to exist on at least some level.What is green furniture?There are many elements to consider when identify-ing green furniture,and I’ve listed only some of the ingredients below that respon-sible furniture makers are taking into account as they design and build.There are other elements to consider,and within the list below,one can continue to dissect each depending on the degree of responsibility a person chooses to pursue.Materials-How are materials sourced and used,and is there waste?Are they renewable,recyclable,reused or repurposed?Are they safe?Do they off-gas?Manufacturing Practices-Is the object designed well,and is it easy/efficient to manufacture?Are alternative sources of energy used during its manufacture?Use-Keep it out of the landfill!Is the object durable,useable,and/or multi-functional?What happens at the object’s end of life?Is it easily recycled or repurposed?Fair Labor-Are the folks involved in the manufacture of the object treated and paid fairly?Maybe this doesn’t apply to a one-person woodshop,but what about the laborers who made or processed the materials the furniture maker is using?Transportation-Is the object going to a local client?How are materials trans-ported to the woodshop or place of manufacture?How does the final product reach the client?Is the maker able to walk or ride a bike to work?Rather than try to place my own judgments about what’s green enough,I opted to highlight the green practices that Furniture Society members are endeav-oring.There’s always room for improvement just like there’s always more to learn.It’s my hope that this peek into what different makers,educators,and businesses are doing will inspire even better things to come.展开更多
基金Supported by the National Natural Science Foundation of China(10371051)
文摘We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the first author's previous works on this topic.
文摘This paper describes the researching aim and content of Ergonomics.Some prob-lems existing in modern harvesting system,such as machinery availability,cabin design,occupational accident,noise and vibration are discussed from the viewpoint of Ergonomics.Furthermore,some improving ways and suggestions are presented.
基金financially supported by Iranian Ministry of Science, Research and Technologies and University of Joensuu
文摘An empirical time study was cohducted to evaluate the performance of the current felling and tree processing methods used in Northern Iran＇s Hyrcanian forest. Motor-manual felling is done mostly in winter, while tree processing starts when the felling season ends. We identified the elements of felling and processing work phases, and 142 cycles and 110 cycles were respectively recorded for felling and processing. On the basis of data analysis （time study）, we developed statistical models of effective time consumption in the respective work phase and for its total productivity. The production rate of felling with and without delay time was 9.7 and 11.65 trees per hour （0.17 USD.m^-3 and 0.21 USD-m^-3）, and the average production cost with and without delay was 1.21 USD and 1.45 USD per tree, respectively. The average productivity of processing was 35 m^3 per effective hour and the average unit cost of processing was 0.92 USD.m^-3.
文摘Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests, the selective cutting performed as single and group selection cutting in the region. The selective cutting was performed on a 42-ha tract with an average slope of 30%. The results indicate that felling time for per tree is most affected by diameter at breast height, the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method. The production rate in single and group selection cutting were 21.2 m^3·h^-1 and 28.4 m^3·h^-1 for one person, respectively. Considering the gross and net production rate in single and group selection cutting, the unit cost was 1.11 USD.m^-3 and 0.88 USD.m^-3, respectively. The results indicate that group selection cutting can be more profitable than single-tree selection method.
文摘Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following phases.In this research, in order to examine the reduction of costs with respect to present and planned operations, the starting time of the harvesting or cutting phase and work flow were recorded. The starting time of each phase of the entire operation was recorded as well. Before harvesting the marked tree, the appropriate felling direction was determined and the azimuth of the correct direction was taken.The results indicate that there was not a meaningful relationship between the differences in direction of a leaning tree compared with the felling direction. However, there was a significant relationship between the difference of the defined and felling direction and the difference in tree leaning and defined direction. The same trend was observed between tree leaning and felling directions and tree leaning and defined directions. On the other hand,there was no significant relationship between tree leaning and felling directions and the defined and tree felling directions. In addition, this research shows that with an increase in tree volume, the time for tree cutting rose.Furthermore, when the difference of tree leaning and felling direction decreased, the time to cut the tree declined.The regression equation is Y = 168.9–0.14（the difference between tree leaning and felling direction） ＋ 0.7（volume）.
文摘The cause of stop marks of fabrics in weaving is introduced, and the floating displacement of the cloth fell during loom stoppage is a primary cause of stop marks. The stop marks caused by fabric system are analyzed. A new method to eliminate stop marks by using the electronic let-off system is presented. This new method needn't any special detecting equipment, it can control the fell position by the powerful control program,so the cost is decreased greatly. The method is so flexible that can be applied to weaving all kinds of fabrics.
文摘The study evaluated the productivity and energy balance of the harvesting and the extraction of wood in plantation of exotic tree species, i.e., Pinus patula （Schiede ex Schlectendahl et Chamisso） and Cupressus lusitanica （Mill.）. The harvesting and extraction operations concerned clear-cut felling on two different types of terrain （gentle and steep terrain） and two levels of prun- ing. The results show that cutting is not affected by the terrain gradient whereas the pruning condition shows a significant effect on the delimbing operation. The productivity of cutting is evaluated at 28.1 m3.d-1 for unpruned trees and at 30.2 m3.d t for pruned trees. For the extraction phase, rolling was significantly affected by terrain conditions. On steep terrain, the gross productivity can be evaluated at 22.5 m3.d 1 for an extraction distance of 40 m, while for the same distance on gentle terrain the productivity decreases to 14.1 m3.d~. As a result, the steep terrain condition showed higher energy efficiency, suggesting that it is the more efficient system of extraction. The productivity model and the energy balance resulting from the study provide a better understanding of the variables af- fecting motor-manual cutting and rolling extraction in exotic plantations in Uganda.
文摘In the afternoon of October 29th,2014,Ordifen Cup 2014 China Lingerie Design Contest unveiled during China Fashion Week.Jointly held by China Fashion Association and Ordifen International Group,the contest presented us a grand feast with the essence of Ordifen’s ten years dedication.Tiny but delicate,the lingerie condenses the charisma of both culture and fashion in the small piece of cloth.Time goes so fast all in the blink of an eye.
文摘Forest degradation and biomass damage resulting from logging is currently difficult to evaluate with satellite images, but contributes substantially to carbon emissions in the tropics. To address this situation, we modelled how changes in the minimum felling diameter affect stem density, basal area and the related carbon biomass at the end of the felling cycle （30 years） in a semi-deciduous natural forest in Cameroon. With new MFDs estimates, at 7% logging damage rate, we found that the stem density of initially harvestable trees reduces from 12.3 （50.4 MgC·ha^-1） to 6.7 （32.5 MgC·ha^-1） trees per ha and the number of initial residual trees increases from 80 （18.9MgC·ha^-1） to 85.7 （36.8 MgC·ha^-1） trees per ha. This corresponds to an avoided damage estimated at 17.9 MgC·ha^-1. We also found that increasing mortality and damage intensity also increases the damage on carbon biomass estimated to be 8.9 MgC·ha^-1 at 10% or to be 17.4 MgC.hal at 15% logging damage. Overall, our study shows that proper determination of MFD of logged species taking into consideration their capacity of reconstitution and the Reduced Impact Logging can avoid the loss of up to 35 MgC·ha^-1.
文摘(1) Rare earth price index Rare earth price index increased at first but fell during the end of December 2016. It grew from 115.3 to the highest of 118.5 and then fell to 116.8 at the month end. (2) Yttrium-medium and europium-rich mineral Listed price of yttrium-medium and europium-rich minerals averaged 195,000 yuan/ton in November, maintaining flat since the beginning of 2016. However, the real deal price was far lower than the listed one.
文摘China’s rare earth export volume fell in January Analysis of customs statistics showed that China’s rare earth export volume continued to fall in January2019.Compared with January 2018, export volume fell by 1.7 percent to 3752.9 tons, while average export prices rose by 6.0percent to$9.8/kg.
文摘China ramps up its efforts to safeguard juveniles from the Internet gaming addiction Just before this year’s national college entrance exam,or the gaokao,on June 7-8,a letter from a despairing mother of student made a big splash on Weibo,a Chinese Twitter-like microblogging platform.The mother described how her son,who used to be an outstanding learner,failed the exam
文摘The Furniture Society is a member-based nonprofit organization founded in 1996.Its mission is to advance the art of furniture making by inspiring creativity,promoting excellence and fostering an understanding of this art and its place in society.By sponsoring a variety of programs that contribute to the education and enrichment of members and the public,the Furniture Society champions excel-lence,refinement,responsibility,and craftsmanship in furniture.It seems that when it comes to woodworking and working with our hands,we are inherently more connected to nature than many other occupations.I attend the Furniture Society’s annual conference every year in June.In almost every furniture maker presentation that I’ve listened to,the artist has mentioned nature as a source of inspiration.And in most encounters with fellow makers,I find that the lot genuinely tries to do good by our planet and its limited resources.Of course,the level of awareness varies among each maker,but consciousness of how we’re using resources seems to exist on at least some level.What is green furniture?There are many elements to consider when identify-ing green furniture,and I’ve listed only some of the ingredients below that respon-sible furniture makers are taking into account as they design and build.There are other elements to consider,and within the list below,one can continue to dissect each depending on the degree of responsibility a person chooses to pursue.Materials-How are materials sourced and used,and is there waste?Are they renewable,recyclable,reused or repurposed?Are they safe?Do they off-gas?Manufacturing Practices-Is the object designed well,and is it easy/efficient to manufacture?Are alternative sources of energy used during its manufacture?Use-Keep it out of the landfill!Is the object durable,useable,and/or multi-functional?What happens at the object’s end of life?Is it easily recycled or repurposed?Fair Labor-Are the folks involved in the manufacture of the object treated and paid fairly?Maybe this doesn’t apply to a one-person woodshop,but what about the laborers who made or processed the materials the furniture maker is using?Transportation-Is the object going to a local client?How are materials trans-ported to the woodshop or place of manufacture?How does the final product reach the client?Is the maker able to walk or ride a bike to work?Rather than try to place my own judgments about what’s green enough,I opted to highlight the green practices that Furniture Society members are endeav-oring.There’s always room for improvement just like there’s always more to learn.It’s my hope that this peek into what different makers,educators,and businesses are doing will inspire even better things to come.
