Search

The second‐law analysis evaluates the irreversibilities of a process. Systematic study of the relationship between thermodynamic efficiency and process modifications enhances process synthesis. The Allam cycle is an oxy‐fuel combustion cycle with nearly complete carbon capture that offers greater efficiency than current electricity generating systems. This study applies lost work analysis to the original Allam cycle and three modifications to obtain the distribution of irreversibilities and the effects of different configurations among potential process improvements for more sustainable power generation. The major inefficiencies are from the combustors and heat exchangers. We also examine the economic profitability of the alternatives. The largest equipment costs are for the turbines, compressors, and recuperators. We find that improving efficiency leads to less economic return; a configuration with partial compression has the highest efficiency, while the original Allam cycle has the highest profitability. We discuss how to resolve this apparent conflict between sustainability and profitability. [ABSTRACT FROM AUTHOR]

Aim: To investigate the possible covariation of grey matter volume (GMV) and white matter fractional anisotropy in infants with spastic cerebral palsy (CP) and periventricular white matter injury. Method: Thirty‐nine infants with spastic CP and 25 typically developing controls underwent structural magnetic resonance imaging and diffusion tensor imaging. Multimodal canonical correlation analysis with joint independent component analysis were used to capture differences in GMV and fractional anisotropy between groups. Correlation analysis was performed between imaging findings and clinical features. Results: Infants with spastic CP showed one joint group‐discriminating component (i.e. GMV‐fractional anisotropy) associated with regions in the cortico‐basal ganglia‐thalamo‐cortical loop and in the corpus callosum compared to typically developing controls and one modality‐specific group‐discriminating component (i.e. GMV). Significant negative correlations were found between loadings in certain regions and the motor function score in spastic CP. Interpretation: In infants with spastic CP, covarying GMV‐fractional anisotropy and altered GMV in specific regions were implicated in motor dysfunction, which confirmed that simultaneous GMV and fractional anisotropy changes underly motor deficits, but might also extend to sensory, cognitive, or visual dysfunction. These findings also suggest that multimodal fusion analysis allows for a more comprehensive understanding of the relevance between grey and white matter structures and its crucial role in the neuropathological mechanisms of spastic CP. [ABSTRACT FROM AUTHOR]

Objective: Lifelong premature ejaculation (PE) is regarded as one of the most common male sexual dysfunction. We aimed to detect whether insula-related brain functional networks are altered in lifelong PE patients and whether such alterations are "normalised" after selective serotonin reuptake inhibitors (SSRI) administration. Methods: Twenty-three drug-naive lifelong PE patients and 30 healthy controls (HC) were recruited in current study. All subjects underwent resting-state functional magnetic resonance imaging (fMRI) scan at first. One hour after dapoxetine administration, all patients underwent fMRI scanning again. The degree centrality (DC), amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) analysis, and ROI-based functional connectivity (FC) analysis were applied to calculate the abnormalities in insula-related functions among three groups. Results: Compared to HC group, PE patients at baseline showed significantly altered DC, ALFF, and ReHo value of the bilateral insula, which subsequently showed a "normalised" trend after dapoxetine administration. Additionally, compared to HC group, PE patients at baseline showed significantly decreased FC between insula and precentral gyrus, inferior frontal gyrus, middle/inferior temporal gyrus, and caudate, while patients after dapoxetine administration showed increased insula-related FC in anterior cingulate cortex and decreased FC in thalamus and middle/inferior temporal gyrus. The main effects of dapoxetine were located in precentral gyrus, inferior frontal gyrus, caudate, and limbic system. Conclusions: Our findings report altered brain mechanism of insula in lifelong PE patients and also indicate that dapoxetine can "normalise" the abnormal function of the insula to certain extent in lifelong PE patients. [ABSTRACT FROM AUTHOR]

In this paper, graphene oxide (GO) was prepared by modified Hammer's method using graphite, which was then modified with silane coupling agent (MGO). With two-roll mill mixing method, GO was used as filler and composites like nitrile-butadiene rubber (NBR)/GO(MGO) composites and nitrile-butadiene rubber (NBR)/ 2,2'-methylenebis(6-tert-butyl-4-methyl-phenol) (AO-2246)/ GO(MGO) composites were prepared. Fourier Transform Infrared Spectrometer (FT-IR), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) were used to observe and study the molecular structure and morphology of GO, MGO and the composites. Dynamic Mechanical Analyzer (DMA) was used to study the damping properties of the composites. The composites reinforced by GO and MGO exhibited better damping and mechanical property. The damping property of NBR/GO composites weakens but the damping property of NBR/AO-2246/GO composites enhances with increase graphene oxide (GO). The damping property of the composites is enhanced by the addition of MGO. The main reason of the excellent properties of the graphene derivatives is its structural characteristics and the associated hydrogen bonds in the structure. [ABSTRACT FROM AUTHOR]

Graphene has been considered an ideal nanoscale reinforced phase for preparing high-performance composites, but the poor compatibility and weak interfacial interaction with the matrix have limited its application. Here a highly effective and environmentally friendly method for the functionalization of graphene is proposed through an interaction between as-exfoliated graphene and (3-aminopropyl) triethoxysilane (KH550), in which 1-butylsulfonate-3-methylimidazolium bisulfate (BSO3HMIm)(HSO4) ionic-liquids-modified graphene was prepared via an electrochemical exfoliation of graphite in (BSO3HMIm)(HSO4) solution, then (BSO3HMIm)(HSO4)-modified graphene as a precursor was reacted with amine groups of KH550 for obtaining (BSO3HMIm)(HSO4)/KH550-functionalized graphene. The final products as filler into carboxylated acrylonitrile‒butadiene rubber (XNBR) improve the dynamic mechanical properties. The improvement in the dynamic mechanical properties of the nanocomposite mainly depends on high interfacial interaction and graphene's performance characteristics, as well as a good dispersion between functionalized graphene and the XNBR matrix. [ABSTRACT FROM AUTHOR]

Organic hybrid damping materials have achieved sustainable development in recent years for superior damping properties due to the hydrogen bonding of hindered phenol. However, the aggregation and crystallization of hindered phenol in the matrix can lead to a sharp decline in material properties. Thus, a series of hindered phenol hybrid carboxylated nitrile rubber (XNBR) composites with different types and contents of hindered phenol were prepared by melt blending to study the effects of different hindered phenol on the properties of organic hybrid damping materials. A dynamic mechanical analyzer (DMA) and scanning electron microscope (SEM) were used to study the dynamic mechanical properties and cross-section morphology of composites. X-ray diffraction (XRD) was used to study the crystallization of hindered phenol. The results show that the properties of organic hybrid damping materials were affected by the structure of hindered phenol, and that hindered phenol molecules with a linear structure had better performances. The greater the number of hydrogen bonds between hindered phenol and the XNBR matrix, the more difficult it was for the hindered phenol to crystallize. [ABSTRACT FROM AUTHOR]