Abstract: A rotary cutting saw includes a base disk; and a plurality of abrasive segments which are fixed to an outer circumferential surface of the base disk, and which have respective outer surfaces cooperating with each other to constitute an outer circumferential surface of the rotary cutting saw; wherein each of the abrasive segments has at least one recess opening in the outer surface thereof; wherein each of the at least one recess has a radially outer portion and a radially inner portion which is located inwardly of the radially outer portion as viewed in a radial direction of the base disk; and wherein the radially outer portion has a width that is constant in the radial direction, and the radially inner portion has a width that varies in the radial direction.

Abstract: A rotary cutting saw including (a) a base disk and (b) a plurality of abrasive segments fixed to an outer circumferential surface of the base disk and are spaced apart from each other in a circumferential direction of the base disk. The base disk has a plurality of slits which are formed in the outer circumferential surface of the base disk and are located between adjacent ones of the abrasive segments in the circumferential direction. Each slit extends inwardly in a radial direction of the base disk from the outer circumferential surface of the base disk. Each of the abrasive segments includes abrasive grains and wear-resistant grains each of which has a size substantially equal to a size of each of the abrasive grains. The wear-resistant grains are exposed on a side surface of each abrasive segment and are regularly arranged on the side surface.

Abstract: A rotary cutting saw including (a) a base disk and (b) a plurality of abrasive segments fixed to an outer circumferential surface of the base disk and are spaced apart from each other in a circumferential direction of the base disk. The base disk has a plurality of slits which are formed in the outer circumferential surface of the base disk and are located between adjacent ones of the abrasive segments in the circumferential direction. Each slit extends inwardly in a radial direction of the base disk from the outer circumferential surface of the base disk. Each of the abrasive segments includes abrasive grains and wear-resistant grains each of which has a size substantially equal to a size of each of the abrasive grains. The wear-resistant grains are exposed on a side surface of each abrasive segment and are regularly arranged on the side surface.

Abstract: A rotary cutting saw comprising: a base disk; and a plurality of abrasive segments which are bonded to an outer circumferential surface of the base disk so as to be spaced apart from each other in a circumferential direction of the base disk. The base disk has a plurality of slits which are formed in the outer circumferential surface of the base disk so as to be located between the abrasive segments in the circumferential direction. Each of the slits is defined by a pair of side surfaces opposed to each other in the circumferential direction, and a part-cylindrical surface defining a part of a cylinder whose axis is parallel to the axial direction. The part-cylindrical surface has a circumferential width which is larger than a circumferential distance between the radially inner end portions of the side surfaces. The part-cylindrical surface is smoothly connected to one of the side surfaces without a stepped portion therebetween.

Abstract: In a diamond cutting saw blade, a plurality of slits 1 are formed at regular intervals on the outer periphery of a disc-shaped iron substrate 2, and a plurality of segment chips 3 are fixed onto the outer periphery of the disc-shaped iron substrate 2. Two trapezoidal concave portions 4 which expand outwardly are formed on both sides of the outer periphery of each segment chip 3. Further, a trapezoidal concave portion 5 is formed at the intermediate position of the segment chip 3 on a joint surface of the iron plate 2 so as to expand toward the joint surface. At the corner where a bottom surface 4a and a tapered surface (side surface) 4b of the concave portion 4 formed on the outer periphery intersect, there is formed a curved surface 4c having a radius of 1.0 to 2.5 mm. Similarly, in a concave portion 5 formed in the inner periphery of the segment chip 3, there is formed a curved surface 5 c having a radius of 1.0 to 2.

Abstract: A process for producing butanol using a Clostridium microorganism and preferably Clostridium sp. AH-1 (FERM-P 6093, ATCC 39045) in a culture medium containing a cellulose material as the carbon source to produce said butanol and recovering the butanol from the culture medium. The invention also provides a novel composition of said Clostridium sp. AH-1 (FERM-P 6093, ATCC39045).