We propose a simple mathematical model by applying Michaelis-Menton equations of enzyme kinetics to study the mutualistic interaction between the leaf cutter ant and its fungus garden at the early stage of colony expansion. We derive sufficient conditions on the extinction and coexistence of these two species. In addition, we give a region of initial condition that leads to the extinction of tw...

In the field of free-form machining, CAM software offers various modes of tool-path generation, depending on the geometry of the surface to be machined. Manufactured surface quality results from the choice of machining strategy and machining parameters. The objective of this paper is to provide a 3D surface roughness parameter that formalizes the relative influence of both machining parameters ...

Hu Shi*, Guofang Gong**, Huaiyin Liu***, Lintao Wang**** *Corresponding author, Zhejiang University Hangzhou, Zhejiang, 310027, China, E-mail: [email protected] **Zhejiang University Hangzhou, Zhejiang, 310027, China, E-mail: [email protected] ***Zhejiang University Hangzhou, Zhejiang, 310027, China, E-mail: [email protected] ****Zhejiang University Hangzhou, Zhejiang, 310027, China, E-mail: ...

This paper presents the suitable depth of cut, spindle speed and feed rate that will be chosen during machining. If thus parameters are not considered, this can provoke abnormal tool behavior such as chatter. Chatter will limit the tool life which only can be use for just a few times. To predict the chatter occurs, the parameters will be use are spindle speed, depth of cut and feed rate. CNC ma...

NC machining is being used to create increasingly complex shapes. These complex shapes are used in a variety of defense, aerospace, and automotive applications to (1) provide performance improvements, and (2) create high performance tooling (e.g., molds for injection molding). The importance of the machining process is increasing due to latest advances in high speed machining that allows machin...

This research was conducted to evaluate abrasion resistance of high-volume fly ash concrete. A reference plain portland cement concrete was proportioned to obtain 28day strength of 41 MPa. Concrete mixtures were also proportioned to have two levels of cement replacements (50 and 70%) with an ASTM Class C fly ash. Abrasion tests were carried out using the rotating cutter method as per ASTM C-944...

Helical milling operations are used to generate or enlarge boreholes by means of a milling tool. The bore diameter can be adjusted through the diameter of the helical path. The kinematics of helical milling on a three axis machine tool is analysed firstly. The relationships between processing parameters, cutting tool geometry characters with machined hole feature are formulated. The feed motion...

How animals sense, process, and use magnetic information remains elusive. In insects, magnetic particles are candidates for a magnetic sensor. Recent studies suggest that the ant Pachycondyla marginata incorporates ironcontaining particles from soil. We used leaf-cutter ants Atta colombica to test whether soil contact is necessary for developing a functional magnetic compass. A. colombica is th...

Abstract For a drill bit, the cutter is most important part to break rock. In oilwell drilling, polycrystalline diamond compact (PDC) bit widely used shear rock formation. this paper, finite element model with including axe-shaped PDC and formation developed study breaking behaviours. Results show that effect of on better than planar cutter. The front rake angle face angel play significant role...