Investigation of Rheological Behavior of Low Pressure Injection Molded Stainless Steel Feedstocks

The purpose of this research is to investigate the influence of different powder loadings of 316L stainless steel (SS) powders on rheological behavior of feedstocks required for low pressure powder injection molding (L-PIM) process. The main idea consists in development of various formulations by varying 316L SS powder contents in feedstocks and evaluating the temperature sensitivity of feedstock via flow behavior index and activation energy. For this purpose, the irregular shape, spherical shape, and combination of both shapes and sizes (bimodal approach) of 316L SS powders are compounded with wax based composite binder. Moreover, the influence of elemental nanosized boron (nB) addition (up to 1.5 wt.%) on rheological properties of irregular shape 316L SS powders is also evaluated using capillary rheometer method. It is observed that rheological parameters for solid powder loading of powder gas atomized (PGA) and bimodal powder P25/75 316L SS underwent sudden change from PGA-69 vol.% to PGA-72 vol.% and P25/75-67 vol.% to P25/75 316L SS 70 vol.%, respectively. Thus it is concluded that PGA-69 vol.% and P25/75-67 vol.% are optimal powder solid loadings corresponding to the lowest values of activation energies

Performance Analysis of Enhanced 3D Printed Polymer Molds for Metal Injection Molding Process

Conventionally, molds for metal injection molding (MIM) process are fabricated using metallic materials using conventional machining processes. Machined metal molds are resilient and therefore could be suitable for mass production of MIM parts. However, with the process of mass production leading to permanent hard tooling, the design is subjected to rigorous testing and iteration before finalization. During design analysis and the iteration process, the demand for MIM parts (part demand) is at low-volume. Therefore, machined metal molds could be costly and time consuming for low volume and customized end-use products. 3D printed molds could be a suitable choice for MIM production for such applications. The present study compares the performance of Fused Deposition Modelling (FDM) 3D printing (3DP) process made polymer molds with an aluminum mold for potential use in MIM process. It was observed that 3DP molds could successfully be used for a limited number of MIM cycles

The Malaysian Acute Vascular Events Risk (MAVERIK) study protocol: studying genetic and other determinants of first-ever myocardial infarction in Malaysia (Preprint)

INTRODUCTION: Although the burden of premature myocardial infarction (MI) is high in Malaysia, direct evidence on the determinants of MI in this multi-ethnic population remains sparse. The Malaysian Acute Vascular Events Risk (MAVERIK) study is a retrospective case-control study established to enable investigation of genomic, lipid-related and other determinants of acute MI in Malaysia. To our knowledge, it represents the largest case-control study of MI and related traits in Malaysia. In this paper, we report the study’s design and initial results. METHODS: By June 2019, MAVERIK had enrolled about 2500 patients with first-ever MI and 2500 controls without cardiovascular disease (CVD), frequency-matched by age, sex and ethnicity, from 17 hospitals in Malaysia. For each participant, serum and whole blood have been collected and stored. Clinical, demographic and behavioural information has been obtained using a 200-item questionnaire. RESULTS: Tobacco consumption, history of diabetes, hypertension, markers of visceral adiposity, indicators of lower socioeconomic status, and family history of coronary disease were more prevalent in cases than controls. Crude and adjusted (age, sex) logistic regression models for traditional risk factors indicated that current smoking, previous smoking, history of high blood pressure, history of diabetes mellitus, family history of CHD and obesity (BMI>30) were associated with MI in age- and sex-adjusted models. CONCLUSION: The MAVERIK study can serve as a useful platform to investigate genetic and other risk factors for MI in an under-studied South-East Asian population. It should help to hasten discovery of disease-causing pathways and to inform regionally appropriate strategies that optimise public health action

Investigating Genetic and Other Determinants of First-Onset Myocardial Infarction in Malaysia:Protocol for the Malaysian Acute Vascular Events Risk Study

BACKGROUND: Although the burden of premature myocardial infarction (MI) is high in Malaysia, direct evidence on the determinants of MI in this multi-ethnic population remains sparse. OBJECTIVE: The Malaysian Acute Vascular Events Risk (MAVERIK) study is a retrospective case-control study established to investigate the genomic, lipid-related, and other determinants of acute MI in Malaysia. In this paper, we report the study protocol and early results. METHODS: By June 2019, we had enrolled approximately 2500 patients with their first MI and 2500 controls without cardiovascular disease, who were frequency-matched by age, sex, and ethnicity, from 17 hospitals in Malaysia. For each participant, serum and whole blood have been collected and stored. Clinical, demographic, and behavioral information has been obtained using a 200-item questionnaire. RESULTS: Tobacco consumption, a history of diabetes, hypertension, markers of visceral adiposity, indicators of lower socioeconomic status, and a family history of coronary disease were more prevalent in cases than in controls. Adjusted (age and sex) logistic regression models for traditional risk factors indicated that current smoking (odds ratio [OR] 4.11, 95% CI 3.56-4.75; P30 kg/m(2); OR 1.19, 95% CI 1.05-1.34; P=.009) were associated with MI in age- and sex-adjusted models. CONCLUSIONS: The MAVERIK study can serve as a useful platform to investigate genetic and other risk factors for MI in an understudied Southeast Asian population. It should help to hasten the discovery of disease-causing pathways and inform regionally appropriate strategies that optimize public health action. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/3188