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Effect of spark plasma sintering pressure on mechanical properties of WC-7.5wt% Nano Co
Rumman, Md.R.,Xie, Z.,Hong, S.J.,Ghomashchi, R. BUTTERWORTH - HEINEMANN 2015 MATERIALS AND DESIGN Vol.68 No.-
In this study, Spark Plasma Sintering (SPS), a relatively fast consolidation method assisted with simultaneous application of heat and pressure, was used to produce bulk carbides from mixed WC-7.5wt% Nano Co powders. Different pressures ranging from 30 to 80MPa were applied during sintering to explore its effect on the mechanical properties of resulting carbides. The maximum hardness was found for the samples pressed at 80MPa, which is ~1925HV (18.88GPa), higher than that of the commercially available cemented carbide tools. The marked changes in porosity, hardness, and crack propagation observed in the samples show that the sintering pressure have considerable impact on the mechanical properties of cemented carbides. In particular, the nature of crack initiation and propagation, which is indicative of the fracture toughness of materials, was studied and clarified.
In-plane structural analysis of blind-bolted composite frames with semi-rigid joints
Rumman Waqas,Brian Uy,Jia Wang,Huu-Tai Thai 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.4
This paper presents a useful in-plane structural analysis of low-rise blind-bolted composite frames with semi-rigid joints. Analytical models were used to predict the moment-rotation relationship of the composite beam-to-column flush endplate joints that produced accurate and reliable results. The comparisons of the analytical model with test results in terms of the moment-rotation response verified the robustness and reliability of the model. Abaqus software was adopted to conduct frame analysis considering the material and geometrical non-linearities. The flexural behaviour of the composite frames was studied by applying the lateral loads incorporating wind and earthquake actions according to the Australian standards. A wide variety of frames with a varied number of bays and storeys was analysed to determine the bending moment envelopes under different load combinations. The design models were finalized that met the strength and serviceability limit state criteria. The results from the frame analysis suggest that among lateral loads, wind loads are more critical in Australia as compared to the earthquake loads. However, gravity loads alone govern the design as maximum sagging and hogging moments in the frames are produced as a result of the load combination with dead and live loads alone. This study provides a preliminary analysis and general understanding of the behaviour of low rise, semi-continuous frames subjected to lateral load characteristics of wind and earthquake conditions in Australia that can be applied in engineering practice.
Mechanical Properties and Microstructural Behaviour of Microwave Sintered WC–Co
Raihan Rumman,Lee C. Chuan,Jamie S. Quinton,Reza Ghomashchi 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.6
Cemented carbides have been of great interest within industrially manufacturable hard materials for their mechanical properties. Microwave sintering is known for its application on a range of hard materials. Although it has been widely used, its effecton grain growth of materials still requires clear understanding. Three different types of particle size, ranging from 1–3 μmto 100 nm were used for microwave sintering where temperature was used in this study within the range of 1000–1400 °C,while pressure during initial compaction of powder particles was kept constant. The maximum hardness was observedin the order of nearly 1800 Hv for submicron samples, sintered at 1250 °C. Fracture toughness on the samples reached amaximum of 16 MPa √m for micron samples sintered at 1400 °C. Grain growth in all samples was not more than 1–3 μm,even without the presence of any commercial grain growth inhibitors as part of the composition. Line scanning betweengrains demonstrates the presence of homogenous Co, confirming good mechanical behaviour. The microstructural featuresassociated to the sintering process have also been focused as part of the study, highlighting some challenges in the research.
Anne-Marie Sassenberg,Jane Summers,Rumman Hassan 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7
Sport is a lucrative and universal form of popular culture, transcending international and social boundaries (Andrews & Jackson, 2001) providing sports men and women with increasingly lucrative financial opportunities through involvement in sponsorship and endorsement deals (Colapinto & Benecchi, 2014). Whilst sport celebrities have long been used in marketing communication and sponsorship campaigns to increase levels of consumer interest and attention (Gupta 2009; McCracken 1989; Van der Veen & Song, 2001), what is not well researched, is the role that electronic word-of-mouth communications plays in the transmission of potentially negative effects on consumer attitudes towards the sport celebrity brand image when a transgression occurs. Not only does electronic word-of-mouth communication make the transmission of a transgression immediate and widely disseminated, it also provides numerous opportunities for celebrities themselves to share information about themselves and their lives sometimes resulting in a “too much”, “too soon” and “too often” nexus. With the removal of a social privacy filter common with many of the younger generation, this TMI (too much information) state or increased self-disclosure (Kaplan & Haenlein, 2010) makes managing the brand image of sport celebrities by their managers and their sponsors an increasingly difficult problem.
Insurance-Growth Nexus: Aggregation and Disaggregation
ZULFIQAR, Umera,MOHY-UL-DIN, Sajid,ABU-RUMMAN, Ayman,AL-SHRAAH, Ata E.M.,AHMED, Israr Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.12
The aim of this article is to investigate the relationship between insurance and economic growth at aggregate and disaggregate level for the period 1982-2018. Very few studies have been carried out in this field, with contradictory results and using an aggregate data while, according to different authors, an aggregate data might provide spurious results. The author used Ordinary Least Squares Regressions (OLS) and Granger Causality tests to explore the strength and direction of the relationship between insurance and economic growth at an aggregate level. To check the relationship at disaggregate level life insurance, marine insurance, and property insurance are regressed on trade openness and investment, respectively. Non-life insurance at an aggregate level plays a positive and significant role in promoting economic growth, but life insurance has an insignificant impact on the Pakistan economy. On the other hand, non-life insurances at a disaggregated level such as marine insurance negatively affect a vital part of economic growth, i.e., trade. At the same time, property insurance has a significant and positive role in boosting investment. Life, marine, and property insurance Granger cause economic growth, trade, and investment in a single direction. Nevertheless, is a bi-directional relationship between economic growth and non-life insurance.
Fang, Zhenghuan,Jung, Kyung Hee,Yan, Hong Hua,Kim, Soo-Jung,Rumman, Marufa,Park, Jung Hee,Han, Boreum,Lee, Ji Eun,Kang, Yeo wool,Lim, Joo Han,Hong, Soon Sun S. Karger AG 2018 CELLULAR PHYSIOLOGY AND BIOCHEMISTRY Vol.47 No.5
<P><B><I>Background/Aims:</I></B> Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignant tumors with poor prognosis. Conventional chemotherapies including gemcitabine have failed owing to weak response and side effects. Hence novel treatment regimens are urgently needed to improve the therapeutic efficacy. In this study, we aimed to assess the anticancer activity of melatonin and sorafenib as a novel therapy against PDAC. <B><I>Methods:</I></B> We used various apoptosis assay and PDAC xenograft model to assess anticancer effect <I>in vitro</I> and <I>in vivo</I>. We applied phospho-receptor tyrosine kinase (RTK) array and phospho-tyrosine kinase array to explore the mechanism of the combined therapy. Western blotting, proximity ligation assay, and immunoprecipitation assay were also performed for validation. <B><I>Results:</I></B> Melatonin synergized with sorafenib to suppress the growth of PDAC both <I>in vitro</I> and <I>in vivo</I>. The effect was due to increased apoptosis rate of PDAC cells that was accompanied by mitochondria dysfunction. The enhanced anticancer efficacy by the co-treatment could be explained by blockade of PDGFR-β/STAT3 signaling pathway and melatonin receptor (MT)-mediated STAT3. <B><I>Conclusions:</I></B> Melatonin reinforces the anticancer activity of sorafenib by downregulation of PDGFR-β/STAT3 signaling pathway and melatonin receptor (MT)-mediated STAT3. The combination of the two agents might be a potential therapeutic strategy for treating PDAC.</P>
FANG, ZHENGHUAN,JUNG, KYUNG HEE,YAN, HONG HUA,KIM, SOO JUNG,SON, MI KWON,RUMMAN, MARUFA,LEE, HYUNSEUNG,KIM, KI WOON,YOO, HYE-DONG,HONG, SOON-SUN Spandidos Publications 2015 International journal of oncology Vol.47 No.1
<P>Chronic myeloid leukemia (CML) is characterized by a constitutively active Bcr-Abl tyrosine kinase. Although Imatinib has been proven to be an effective drug against CML, its resistance has been observed with disease relapse due to T315I predominant point mutation. Liriodendron tulipifera L., one of the fastest growing hardwood tree species, exerts antioxidant activity and anti-inflammatory effects. However, its anticancer effect has been minimally reported. In this study, we extracted CD-200 from Liriodendron tulipifera L. and investigated its effect on cell survival or apoptosis in CML cells with Bcr-Abl/T315I (BaF3/T315I) as well as wild-type Bcr-Abl (BaF3/WT). CD-200 inhibited cell proliferation in the BaF3/WT cells, and also in the BaF3/T315I cells with Imatinib resistance. Moreover, it strongly inhibited Bcr-Abl signaling pathways in a dose-dependent manner. Also, it significantly increased the sub-G1 phase and the expression of cleaved PARP and caspase-3, as well as the TUNEL-positive apoptotic cells. In addition, we observed that CD-200 induced apoptosis with a loss of mitochondrial membrane potential by decreasing the expression of Mcl-1 and survivin. Furthermore, CD-200 showed a significant inhibition in tumor growth, compared to Imatinib in BaF3/T315I mouse xenograft models. Taken together, our study demonstrates that CD-200 exhibits apoptosis induction and anti-proliferative effect by blocking the Bcr-Abl signaling pathways in the Bcr-Abl/T315I with resistance to Imatinib. We suggest that CD-200 may be a natural product to target Bcr-Abl and overcome Imatinib resistance in CML patients.</P>