Vibration transmission through rolling element bearings in geared rotor system, part 1

A mathematical model is proposed to examine the vibration transmission through rolling element bearings in geared rotor systems. Current bearing models, based on either ideal boundary conditions for the shaft or purely translational stiffness element description, cannot explain how the vibratory motion may be transmitted from the rotating shaft to the casing. This study clarifies this issue qualitatively and quantitatively by developing a comprehensive bearing stiffness matrix of dimension 6 model for the precision rolling element bearings from basic principles. The proposed bearing formulation is extended to analyze the overall geared rotor system dynamics including casing and mounts. The bearing stiffness matrix is included in discrete system models using lumped parameter and/or dynamic finite element techniques. Eigensolution and forced harmonic response due to rotating mass unbalance or kinematic transmission error excitation for a number of examples are computed

A review of gear housing dynamics and acoustics literature

A review of the available literature on gear housing vibration and noise reduction is presented. Analytical and experimental methodologies used for bearing dynamics, housing vibration and noise, mounts and suspensions, and the overall geared and housing system are discussed. Typical design guidelines as outlined by various investigators are given

Protein expression patterns in HEK-blue-cells treated with Clinacanthus nutans extracts

Background: Clinacanthus nutans (CN) is a small shrub native to tropical Asia known for their anti-oxidant, anti-inflammation, anti-cancer, and anti-viral activities. Objectives: This study aimed to investigate the effect of CN extract on human embryonic kidney cell line (HEK-Blue™-4) in a proteomic perspective. Materials and Methods: Comparative proteomic profiling through two-dimensional sodium dodecyl sulfate gel electrophoresis was performed on HEK-Blue™-4 treated with CN leaf polar extract. Results: We successfully identified seven upregulated proteins, of which five promoted the growth of the HEK-Blue™-4 cells. Interestingly, a potent antioxidant enzyme which neutralizes reactive oxygen or nitrogen species, peroxiredoxin-1 was also upregulated in HEK-Blue™-4 cell lines after treatment with CN leaf polar extract. Conclusion: CN leaf polar extract promotes the growth of HEK-Blue™-4 cells and induced the expression of peroxiredoxin-1, which protects the cells from reactive oxygen species during the inflammation process

Treatment Outcomes of Clevudine versus Lamivudine at Week 48 in Naïve Patients with HBeAg Positive Chronic Hepatitis B

The authors assessed the efficacy and antiviral resistance of 48-week clevudine therapy versus lamivudine in treatment of naïve patients with HBeAg positive chronic hepatitis B. In this retrospective study, a total of 116 HBeAg positive patients, who received 30 mg of clevudine once daily (n=53) or 100 mg of lamivudine once daily (n=63) for 48 weeks, were included. At week 48, clevudine therapy produced a significantly greater mean reductions in serum HBV DNA levels from baseline than lamivudine therapy (-5.2 vs. -4.2 log10IU/mL; P=0.005). Furthermore, a significantly higher proportion of patients on clevudine achieved negative serum HBV DNA by PCR (<13 IU/mL) at week 48 (60.4% vs. 38.1%; P=0.025). The incidence of virologic breakthrough in the clevudine group was significantly lower than in the lamivudine group (9.4% vs. 25.4%; P=0.031). However, rates of alanine aminotransferase normalization and HBeAg loss or seroconversion were similar in the two groups (83.0% vs. 81.0%, 11.3% vs. 11.1%; P=0.813, 1.000, respectively). In conclusion, clevudine is more potent for viral suppression and lower for antiviral resistance at week 48 than lamivudine in treatment of naïve patients with HBeAg positive chronic hepatitis B

Abusive supervision and cyberloafing: A moderated moderation model of moral disengagement and negative reciprocity beliefs

Cyberloafing is a major productivity killer in the workplace. Drawing on social cognitive theory and social exchange theory, we developed and tested a model that examined the underlying mechanisms through which abusive supervision influences cyberloafing. The results showed that abusive supervision is positively related to cyberloafing. This relationship is also moderated by negative reciprocity beliefs. In addition, support was found for the three-way interaction effect of abusive supervision, moral disengagement, and negative reciprocity beliefs on cyberloafing, such that the positive relationship between abusive supervision and cyberloafing is strongest at high levels of moral disengagement and negative reciprocity beliefs

Oxygen carrier derived from ferric sludge for chemical looping combustion of MSW syngas: waste derived material performance and carbon footprint assessment

The utilization of water treatment sludge (i.e., ferric sludge) was explored as the oxygen carrier (OC) for chemical looping combustion (CLC) of municipal solid waste (MSW) syngas. The performance of ferric sludge (FS) in CLC and simultaneous HCl removal was evaluated in a bench-scale fluidized bed, and was compared with iron ore (IO) as a benchmarked OC. The results show that FS (92 %) performed better than IO (82 %) in terms of syngas combustion efficiency and FS was able to remove HCl (77 % removal efficiency) while IO was unable to remove any HCl. Comparison of reaction temperature reveals that FS performed better at lower CLC temperature between 800 °C and 850 °C. Agglomeration was observed when FS was used in extended CLC cycles. Thus, investigation of using inert α-Al2O3 support together with FS for extended CLC cycles was investigated. Agglomeration and sintering were drastically reduced and good combustion efficiency of 88 % for H2 and 74 % for CO was attained. Carbon footprint assessment illustrated that FS was superior as a greener material based on global warming potential of 20 and 100 years. Conversion of FS as an OC were characterized with 104.23 and 108.0 kgCO2/t lower than IO for GWP-20 and GWP-100, exhibiting the competitiveness in the usage of waste-derived material in CLC. Hence, FS can be considered as a novel, cost-effective, and greener OC for CLC. The co-utilization of waste-derived material and waste-derived syngas through CLC would be an integrated solution for improved circularity and sustainability.National Research Foundation (NRF)Public Utilities Board (PUB)This research is supported by the National Research Foundation, Singapore, and PUB, Singapore’s National Water Agency under its RIE2025 Urban Solutions and Sustainability (USS) (Water) Centre of Excellence (CoE) Programme, awarded to Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore (NTU)