Synthesis and Characterization of SAPO-34/6FDA-Durene Mixed Matrix Membrane for CO2 Capture

Membrane separation has become a promising technology in CO2 removal from natural gas sweetening recently. In the present research, a series of SAPO-34/6FDA-durene mixed matrix membranes (MMMs) were developed to remove the CO2 from CH4. The MMMs were fabricated by incorporating different compositions of SAPO-34 fillers into 6FDA-durene polymer matrix. SAPO-34 fillers modified with (3-Aminopropyl)-triethoxysilane (APTES) were synthesized and incorporated into 6FDA-durene polymer matrix in order to study their effects on the membrane defects, as well as their effects on the performances of the resulting MMMs towards the gas separation. The resulting SAPO-34 and silane-modified SAPO-34 were characterized by using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), whereas all the fabricated MMMs were characterized by using Energy Dispersive X-ray (EDX) and SEM. The performances of the membranes in CO2/CH4 separation were tested by using CO2 membrane cell filter test rig (CO2MCEF). The morphology of the silane-modified MMMs showed the improvement on the compatibility between the polymeric and inorganic phases. EDX results showed that the inorganic SAPO-34 particles were evenly distributed in the polymer matrix and no phase separation was found. However, all MMMs showed lower separation performance compared to pure 6FDA-durene membrane mainly due to large inorganic particles size, moisture contact, poor interfacial adhesion and polymer matrix rigidification

Synthesis and Characterization of SAPO-34/6FDA-Durene Mixed Matrix Membrane for CO2 Capture

Membrane separation has become a promising technology in CO2 removal from natural gas sweetening recently. In the present research, a series of SAPO-34/6FDA-durene mixed matrix membranes (MMMs) were developed to remove the CO2 from CH4. The MMMs were fabricated by incorporating different compositions of SAPO-34 fillers into 6FDA-durene polymer matrix. SAPO-34 fillers modified with (3-Aminopropyl)-triethoxysilane (APTES) were synthesized and incorporated into 6FDA-durene polymer matrix in order to study their effects on the membrane defects, as well as their effects on the performances of the resulting MMMs towards the gas separation. The resulting SAPO-34 and silane-modified SAPO-34 were characterized by using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), whereas all the fabricated MMMs were characterized by using Energy Dispersive X-ray (EDX) and SEM. The performances of the membranes in CO2/CH4 separation were tested by using CO2 membrane cell filter test rig (CO2MCEF). The morphology of the silane-modified MMMs showed the improvement on the compatibility between the polymeric and inorganic phases. EDX results showed that the inorganic SAPO-34 particles were evenly distributed in the polymer matrix and no phase separation was found. However, all MMMs showed lower separation performance compared to pure 6FDA-durene membrane mainly due to large inorganic particles size, moisture contact, poor interfacial adhesion and polymer matrix rigidification

Rotor design optimization using a free wake analysis

The aim of this effort was to develop a comprehensive performance optimization capability for tiltrotor and helicopter blades. The analysis incorporates the validated EHPIC (Evaluation of Hover Performance using Influence Coefficients) model of helicopter rotor aerodynamics within a general linear/quadratic programming algorithm that allows optimization using a variety of objective functions involving the performance. The resulting computer code, EHPIC/HERO (HElicopter Rotor Optimization), improves upon several features of the previous EHPIC performance model and allows optimization utilizing a wide spectrum of design variables, including twist, chord, anhedral, and sweep. The new analysis supports optimization of a variety of objective functions, including weighted measures of rotor thrust, power, and propulsive efficiency. The fundamental strength of the approach is that an efficient search for improved versions of the baseline design can be carried out while retaining the demonstrated accuracy inherent in the EHPIC free wake/vortex lattice performance analysis. Sample problems are described that demonstrate the success of this approach for several representative rotor configurations in hover and axial flight. Features that were introduced to convert earlier demonstration versions of this analysis into a generally applicable tool for researchers and designers is also discussed

The Roles of IS Project Critical Success Factors: A Relevatory Case

Research in Critical Success Factors (CSFs) of Enterprise Systems (ES) projects has identified numerous practitioner governance mechanisms for ensuring project success. However, such research has not developed a theory of why certain critical success factors encourage project success. Our research develops such theory on a case study where even though the levels of several critical success factors were weak, the project nevertheless succeeded. Specifically, the logistics ES project succeeded even though there was (1) only marginal top management support, (2) low key user commitment, and (3) change management, training and other critical aspects of user management and communication were not well done. Using a modified dialectical lens, we highlight that project team legitimacy appears to be the underlying CSF, and many heretofore identified CSFs are really manifestations of project team legitimacy

Computation of rotor aerodynamic loads in forward flight using a full-span free wake analysis

The development of an advanced computational analysis of unsteady aerodynamic loads on isolated helicopter rotors in forward flight is described. The primary technical focus of the development was the implementation of a freely distorting filamentary wake model composed of curved vortex elements laid out along contours of constant vortex sheet strength in the wake. This model captures the wake generated by the full span of each rotor blade and makes possible a unified treatment of the shed and trailed vorticity in the wake. This wake model was coupled to a modal analysis of the rotor blade dynamics and a vortex lattice treatment of the aerodynamic loads to produce a comprehensive model for rotor performance and air loads in forward flight dubbed RotorCRAFT (Computation of Rotor Aerodynamics in Forward Flight). The technical background on the major components of this analysis are discussed and the correlation of predictions of performance, trim, and unsteady air loads with experimental data from several representative rotor configurations is examined. The primary conclusions of this study are that the RotorCRAFT analysis correlates well with measured loads on a variety of configurations and that application of the full span free wake model is required to capture several important features of the vibratory loading on rotor blades in forward flight

Mechanism of inhibitory effect of atorvastatin on resistin expression induced by tumor necrosis factor-α in macrophages

Atorvastatin has been shown to reduce resistin expression in macrophages after pro-inflammatory stimulation. However, the mechanism of reducing resistin expression by atorvastatin is not known. Therefore, we sought to investigate the molecular mechanisms of atorvastatin for reducing resistin expression after proinflammatory cytokine, tumor necrosis factor-α (TNF-α) stimulation in cultured macrophages. Cultured macrophages were obtained from human peripheral blood mononuclear cells. TNF-α stimulation increased resistin protein and mRNA expression and atorvastatin inhibited the induction of resistin by TNF-α. Addition of mevalonate induced resistin protein expression similar to TNF-α stimulation. However, atorvastatin did not have effect on resistin protein expression induced by mevalonate. SP600125 and JNK small interfering RNA (siRNA) completely attenuated the resistin protein expression induced by TNF-α and mevalonate. TNF-α induced phosphorylation of Rac, while atorvastatin and Rac-1 inhibitor inhibited the phosphorylation of Rac induced by TNF-α. The gel shift and promoter activity assay showed that TNF-α increased AP-1-binding activity and resistin promoter activity, while SP600125 and atorvastatin inhibited the AP-1-binding activity and resistin promoter activity induced by TNF-α. Recombinant resistin and TNF-α significantly reduced glucose uptake in cultured macrophages, while atorvastatin reversed the reduced glucose uptake by TNF-α. In conclusion, JNK and Rac pathway mediates the inhibitory effect of atorvastatin on resistin expression induced by TNF-α

Threat-Balancing in Vendor Transition

While many outsourcing contracts are expiring, and vendor transition is becoming an increasing concern, little research helps organizations manage vendor transition. This paper explores vendor transition across two case sites. In one case, the outgoing vendor cooperated with the client which resulted in the client distancing itself from interactions between vendors. In the second case, the outgoing vendor was openly hostile, with the result that the client allied with the incoming vendor to manage vendor transition. These findings mirror expectations from balance of threat theory, a political science theory about interactions between nations. Balance of threat theory predicts that outgoing vendor hostility and the capability of the client to mitigate hostility determine whether a client takes a hard or soft balancing strategy during vendor transition

Cure efficiency of dodecyl succinic anhydride as a cross-linking agent for elastomer blends based on epoxidized natural rubber

Blends of a highly epoxidized natural rubber (ENR50) with unmodified natural rubber (NR) and ethylene propylene elastomers (EPDM) were produced to evaluate the mixing and curing characteristics. Dodecyl succinic anhydride was used to cross-link the ENR50 component and the reactivity was assessed by monitoring the evolution of the torque in an oscillatory co-axial cylinder rheometer, as well as by DSC thermal analysis. A physical model was used to obtain a single parameter for the reactivity of the system, which corresponds to the rate constant for first order curing reactions. Although the blends were thermodynamically immiscible, displaying no significant change in Tg, the components were well dispersed at microscopic level. Better mechanical properties were obtained for blends with EPD

Klotho-beta overexpression as a novel target for suppressing proliferation and fibroblast growth factor receptor-4 signaling in hepatocellular carcinoma

<p>Abstract</p> <p>Background</p> <p>We had previously demonstrated overexpression of fibroblast growth factor receptor-4 (FGFR4) in hepatocellular carcinoma (HCC). However, additional molecular mechanisms resulting in amplified FGFR4 signaling in HCC remain under-studied. Here, we studied the mechanistic role of its co-receptor klotho-beta (KLB) in driving elevated FGFR4 activity in HCC progression.</p> <p>Results</p> <p>Quantitative real-time PCR analysis identified frequent elevation of KLB gene expression in HCC tumors relative to matched non-tumor tissue, with a more than two-fold increase correlating with development of multiple tumors in patients. KLB-silencing in Huh7 cells decreased cell proliferation and suppressed FGFR4 downstream signaling. While transient repression of KLB-FGFR4 signaling decreased protein expression of alpha-fetoprotein (AFP), a HCC diagnostic marker, prolonged inhibition enriched for resistant HCC cells exhibiting increased liver stemness.</p> <p>Conclusions</p> <p>Elevated KLB expression in HCC tissues provides further credence to the oncogenic role of increased FGFR4 signaling in HCC progression and represents a novel biomarker to identify additional patients amenable to anti-FGFR4 therapy. The restricted tissue expression profile of KLB, together with the anti-proliferative effect observed with KLB-silencing, also qualifies it as a specific and potent therapeutic target for HCC patients. The enrichment of a liver stem cell-like population in response to extended KLB-FGFR4 repression necessitates further investigation to target the development of drug resistance.</p