Optimization of injection molding parameter of ti-6al-4v powder mix with palm stearin and polyethylene for the highest green strength by using taguchi method

This paper present the Taguchi method of L27 (313) orthogonal array as a tool in optimization of Metal injection molding (MIM) parameters for the highest green strength. Injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed are Parameters to be optimized. Besides those, interaction of the injection pressure, injection temperature and powder loading were studied. The metal powder of Ti-6Al-4V is mixed with binder 60wt% of palm stearin and 40wt% of polyethylene successfully injected at optimum parameter condition: 350 bar of injection pressure, 140oc of injection temperature, 65vol% of powder loading, 50oc of mold temperature, 600 bar of holding pressure, and 10ccm/s of the injection rate. Analysis of variance (ANOVA) for the best signal to noise ratio (S/N) presents the contribution of the parameters to the quality characteristic (green strength). Results show that the mold temperature has highest significant percentage (27.59%) followed by powder loading (15.44%) and injection pressure (12.30%) Nevertheless, the analysis of variance does not show any contribution from interaction

Musculoskeletal MRI protocol

The authors propose a musculoskeletal (MSK) magnetic resonance imaging (MRI) protocol using selected sequences for common orthopaedic indications. Selected sequences allow optimal visualisation of the indicated pathology while screening for other common conditions. The authors emphasise the need for standard positioning of the patient and standard orientation of scan planes to facilitate comparison with follow-up scans

Spectral curve fitting of dielectric constants

Optical constants are important properties governing the response of a material to incident light. It follows that they are often extracted from spectra measured by absorbance, transmittance or reflectance. One convenient method to obtain optical constants is by curve fitting. Here, model curves should satisfy Kramer-Kronig relations, and preferably can be expressed in closed form or easily calculable. In this study we use dielectric constants of three different molecular ices in the infrared region to evaluate four different model curves that are generally used for fitting optical constants: (1) the classical damped harmonic oscillator, (2) Voigt line shape, (3) Fourier series, and (4) the Triangular basis. Among these, only the classical damped harmonic oscillator model strictly satisfies the Kramer-Kronig relation. If considering the trade-off between accuracy and speed, Fourier series fitting is the best option when spectral bands are broad while for narrow peaks the classical damped harmonic oscillator and the Triangular basis fitting model are the best choice

A review of workability of wrought magnesium alloys

Despite being the lightest structural metal, magnesium alloys exhibited poor workability at low temperatures due to their hexagonal closed-packed crystal structure, consequently required them to be processed at elevated temperature. Their highly affinity to oxygen lead them to an easy oxidation. Moreover, they are poor corrosion resistance, poor creep resistance as well as fatigue failure but these can be improved by various techniques of surface treatments and alloying additions. Commercial wrought magnesium alloy grades, its mechanical properties as well as its workability at elevated temperatures are presented. Recent literatures showed that the workability of these alloys is increased at temperatures ranging from 100 to 3500C, 200 to 400 to 300 to 5000C and for AZ, ZK and WE alloy systems, respectively. The purpose of this paper is to review and reveal the issues in processing of wrought magnesium alloy

Spectral curve fitting of dielectric constants

Optical constants are important properties governing the response of a material to incident light. It follows that they are often extracted from spectra measured by absorbance, transmittance or reflectance. One convenient method to obtain optical constants is by curve fitting. Here, model curves should satisfy Kramer-Kronig relations, and preferably can be expressed in closed form or easily calculable. In this study we use dielectric constants of three different molecular ices in the infrared region to evaluate four different model curves that are generally used for fitting optical constants: (1) the classical damped harmonic oscillator, (2) Voigt line shape, (3) Fourier series, and (4) the Triangular basis. Among these, only the classical damped harmonic oscillator model strictly satisfies the Kramer-Kronig relation. If considering the trade-off between accuracy and speed, Fourier series fitting is the best option when spectral bands are broad while for narrow peaks the classical damped harmonic oscillator and the Triangular basis fitting model are the best choice.</p

Injection molding parameter optimization of titanium alloy powder mix with palm stearin and polyethylene for multiple performance using grey relational analysis

This paper outlines the optimization the process of injection molding parameters for feedstock of titanium alloy powder and palm stearin binder using grey relational analysis method. A Grey Relational Grade (GRG) obtained from the Grey Relational Analysis (GRA) is used to solve the inj ection molding operations with the multiple performance characteristic. The L27 (313) of orthogonal array of Taguchi method were performed. Defects, strength and density are important characteristics in determine the quality of the green part. Using these characteristics, the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed are optimized in the study. From the analysis of variance (ANOVA), the injection temperature has the highest contribution to the quality of green part followed by injection pressure, powder loading, mold temperature, injection rate and holding pressure

Comparative study of three Marantodes pumilum varieties by microscopy, spectroscopy and chromatography

Marantodes pumilum (Blume) Kuntze (synonym: Labisia pumila (Blume) Fern.-Vill), Primulaceae, is well known for its traditional use as a post-partum medication among women in Malaysia. Three varieties of M. pumilum, var. alata Scheff., var. pumila and var. lanceolata (Scheff.) Mez. are commonly used. Nowadays, M. pumilum powder or extracts are commercially available as herbal supplements and beverages. Authentication of the variety is an important component of product quality control. Thus, the present work was aimed to compare the three varieties using microscopic, spectroscopic and chromatographic techniques. Microscopic anatomical examination and powder microscopy were performed on fresh and dried plant materials, respectively. Fingerprint profiles of the varieties were obtained using attenuated total reflectance-Fourier transform infrared spectrophotometer, high performance thin layer chromatography and high performance liquid chromatography. The microscopic examination showed presence of anisocytic stomata, scale and capitate glandular trichome in all varieties. The type of stomata and trichomes, outline structure of stem and leaf margin, petiole and midrib, organization of vascular system, areolar venation, pattern of anticlinal walls, the distribution of secretory canals and cell inclusion as well as the measurement of selected structures could be used to distinguish and identify each variety of M. pumilum. In addition, spectroscopic and chromatographic fingerprint analyses of the three varieties exhibited distinguishable profiles based on the intensity of certain peaks or bands. The findings from this study will provide systematic identification for these varieties. Keywords: Anatomy, ATR-FTIR, HPLC, HPTLC, Marantodes pumilum, Microscop