It is very important to know how to allocate tolerances economically for parts in a CAD

Abstract-Tool wear condition monitoring has the potential to play a critical role in ensuring the dimensional accuracy of the workpiece and prevention of damage to cutting equipment. It could also help in automating cutting processes. In this paper, the feed cutting force estimated with the aid of an inexpensive current sensor installed on the ac servomotor of a computerized numerical control turning center is used to monitor tool wear condition. To achieve this, the feed drive system is modeled, using neuro-fuzzy techniques, to provide the framework for estimating the feed cutting force based on the feed motor current measured. Functional dependence of the feed cutting force on tool wear and cutting parameters are then expressed in the form of a difference equation relating variation in the feed cutting force to tool wear rate. The computerized system automatically compares successive feed cutting force estimates and determines the onset of accelerated tool wear in order to issue a request for tool replacement. Experimental results show that the tool wear condition monitoring is effective and industrially applicable.

1IntroductionPolymer bonded explosives (PBXs) [1][2][3][4] have usually been considered as ap articulate composite material containing the energetic materials hexahydro-1,3,5-trinitro-1,3,5-s-triazine (RDX) embedded in av iscoelastic polymer binder. PBXs are widely used in av ariety of conventional engineering and aerospace fields. As ah ighly-filled composite material, PBX exhibits complex physical and mechanical properties that are dependent on an umber of variables, such as temperature, strain rate, grains weight, and size distribution of grains, etc. [5,6].The Los Alamos National Laboratory (LANL) performed al ot of research on dynamic mechanical properties of PBXs. These results suggested that dynamic mechanical properties of PBX are strongly influenced by strain rate and temperature [7][8][9][10].A lso, the compressive strength is enhanced when increasing strain rate or decreasing temperature. PBX9501i sw idely researched at present,a nd the result illustrated that PBX9501 duringh igh-rate loading continue straining after the maximum flows tress have been achieved. Figure 1s hows the published compressive stress-strain data on PBX9501 currently known to the authors. When the peak strengths of PBX9501 are achieved, the flow strength beginst od ecline sharply because of damage accumulation. Graye tal. [11] revealed that at high-rate PBX 9501 fails via predominantly transgranular cleavage through the HMX crystals. Strains to failure remain almost constant throughout,a talevel of approximately 1-3 %. In fact, these damagep rocesses give rise to the enhanced sensitivity of PBX9501 followinga ni mpact.In the presented work, the micromechanical modelh as profited greatly from the theoretical analysis of Weng and co-workers [12-17] and considerable referencet ot heir work is madet hroughout this article. Their work is based on Eshelby's celebrateds olution of the stressa nd strain fields arising from the presence of an ellipsoidal inhomogeneity in an elastic matrix and Mori and Ta naka'se ffective medium theory,w hich was used to extendE shelby's analysis to larger valueso ff iller concentration [18,19].C lements and Mas have put forth am ethod that is ah ybrid of two Abstract:T he dynamic mechanical properties of PBX1314 and its binder are systematicallyi nvestigated. Based on split-Hopkinson pressure bar technique, the experimental results of PBX1314 and its binder are obtainedu nder high strain rate. Ac onstitutive theory is developed for modeling the mechanical response of dynamically loaded PBX1314 binder.T oa ccomplish this aim, the PBX1314 binderi sa ssayed by relaxation tests at different temperatures, in order to apply the time-temperature superposition principle (TTSP) and raise the masterc urves, based on WLF equation.The rate dependence of mechanical response of the polymer binder is accounted for by ag eneralized Maxwell viscoelasticity model. The basis for this work is Mori and Ta naka's effectivem ediumt heory.T he grains in this analysis are assumed to be spherical and uniformly distributed in the b...

Raw multiwall carbon nanotubes (MWNTs) were first treated with strongly oxidated acid to form MWNTs-COOH and driven to a high dispersion quality in the dispersing medium via ultrasonic method. Then the MWNTs/poly (p-phenylene benzobisoxazole)(MWNTs-COOH/PBO) nanocomposites were prepared by an in situ polymerization technique. In this process, the morphological structure of MWNTs and MWNTs-COOH were investigated by XPS, FTIR, and TEM. The experimental results showed that the carboxyl group was introduced into the surface of nanotubes and the length of nanotubes was shortened. The images of SEM and AFM illustrated that the MWNTs-COOH was homogeneously dispersed in PBO matrix, and the DTA analysis indicated that the molecular weight of MWNTs-COOH/PBO was almost equal to that of PBO. Furthermore, the thermogravimetry results proved that the thermal property of MWNTs-COOH/PBO was more stable than that of PBO. Also, the knot strength and the tensile strength of MWNTs-COOH/PBO were 30% higher than that of PBO. In addition, the reaction route of the MWNTs-COOH and PBO oligomer was given according to the ATR-FTIR spectra of PBO polymer and MWNTs-COOH/PBO.

The room-temperature aging method was first introduced to ZnO-based perovskite solar cells to improve the stability of ZnO/CH3NH3PbI3 bilayer. The prepared devices with a maximum efficiency of 9.4% exhibited promising stability under ambient conditions.

In automated manufacturing systems such as flexible manufacturing systems (FMSs)

Ag-molecularly imprinted polymer (MIP) hybrid composites (Ag@MIPs) were prepared for the ultra-sensitive detection of organic pollutants in water based on surface enhanced Raman scattering (SERS).

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