Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission ...Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission Machinery Directive as a national law, which demands protection against noise emission in the design phase of new machines. In order to accomplish this, it is necessary to examine and locate the causes of emissions on existing machines. In this paper, the sound source is located through sound intensity measurements, using planing machines as an example, which are particularly noise-intensive woodworking machines. In addition, different influencing parameters on noise emission are analyzed, such as manual and automatic feed, rotational speed and the influence of the type of wood of the workpiece.展开更多
Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk alloy.The effects of m...Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk alloy.The effects of mechanical alloying parameters(i.e.,milling time,milling speed,ball-to-powder mass ratio and Zn content)and their interactions were investigated involving 4 numerical factors with 2 replicates,thus 16 runs of two-level fractional factorial design.Results of analysis of variance(ANOVA),regression analysis and R2 test indicated good accuracy of the model.The statistical model determined that the elastic modulus of biodegradable Mg-Zn alloy was between 40.18 and 47.88 GPa,which was improved and resembled that of natural bone(30-57 GPa).Corrosion resistance(mass loss of pure Mg,33.74 mg)was enhanced with addition of 3%-10%Zn(between 9.32 and 15.38 mg).The most significant independent variable was Zn content,and only the interaction of milling time and ball-to-powder mass ratio was significant as P-value was less than 0.05.Interestingly,mechanical properties(represented by elastic modulus)and corrosion resistance(represented by mass loss)of biodegradable Mg-Zn alloy can be statistically predicted according to the developed models.展开更多
文摘Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission Machinery Directive as a national law, which demands protection against noise emission in the design phase of new machines. In order to accomplish this, it is necessary to examine and locate the causes of emissions on existing machines. In this paper, the sound source is located through sound intensity measurements, using planing machines as an example, which are particularly noise-intensive woodworking machines. In addition, different influencing parameters on noise emission are analyzed, such as manual and automatic feed, rotational speed and the influence of the type of wood of the workpiece.
基金supported by the Universiti Sains Malaysia RU-PRGS (No. 8046026)Universiti Sains Malaysia FRGS by Ministry of High Education, Malaysia (No. 6071304)
文摘Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk alloy.The effects of mechanical alloying parameters(i.e.,milling time,milling speed,ball-to-powder mass ratio and Zn content)and their interactions were investigated involving 4 numerical factors with 2 replicates,thus 16 runs of two-level fractional factorial design.Results of analysis of variance(ANOVA),regression analysis and R2 test indicated good accuracy of the model.The statistical model determined that the elastic modulus of biodegradable Mg-Zn alloy was between 40.18 and 47.88 GPa,which was improved and resembled that of natural bone(30-57 GPa).Corrosion resistance(mass loss of pure Mg,33.74 mg)was enhanced with addition of 3%-10%Zn(between 9.32 and 15.38 mg).The most significant independent variable was Zn content,and only the interaction of milling time and ball-to-powder mass ratio was significant as P-value was less than 0.05.Interestingly,mechanical properties(represented by elastic modulus)and corrosion resistance(represented by mass loss)of biodegradable Mg-Zn alloy can be statistically predicted according to the developed models.
