Thermochemical hydrogen production using Rh/CeO2/γ-Al2O3 catalyst by steam reforming of ethanol and water splitting in a packed bed reactor

This study is focused on investigating the dual performance of Rh/CeO₂/γ-Al₂O₃ catalyst for steam reforming of ethanol (SRE) and thermochemical water splitting (TCWS) using a packed bed reactor. The catalyst is designed to be thermally stable containing an active phase of Rh and the redox component of CeO₂ for oxygen exchange, supported on γ-Al₂O₃. The catalyst has been characterised by SEM, XRD, BET, TPR, TPD, XPS and TGA before testing in the reactor. The optimal temperature for SRE reaction over this catalyst is between 700 °C and 800 °C to produce high concentrations of hydrogen (~60%), and low CO and CH₄. The selectivity towards CO and CH₄ is higher at low temperatures and drops with rise in reaction temperature. Further, Rh/CeO₂/γ-Al₂O₃ is found to be active for TCWS at relatively low temperatures (≤1200 °C). At temperatures as low as 800 °C, this catalyst is especially found suitable for multiple redox cycles, producing a total of 48.9 mmol/g_cat in four redox cycles. The catalyst can be employed for large number of redox cycles when the reactor is operated at lower temperatures. Finally, the reaction pathways have been proposed for both SRE and TCWS on Rh/CeO₂/γ-Al₂O₃ catalyst.     

A review of the experimental techniques for the measurement of heat and temperatures generated in some manufacturing processes and tribology

Several techniques have been developed over time for the measurement of heat and the temperatures generated in various manufacturing processes and tribological applications. They include: (1) thermocouples — the embedded thermocouple and the dynamic thermocouple (or the chip–tool thermocouple in the case of cutting), (2) infra-red photography; (3) infrared optical pyrometers, (4) thermal paints, (5) materials of known melting temperatures, either in the powder form, or, as a thin film, and (6) change in microstructure with temperature in the case of high-speed steel tools, to name some. Each technique has its own advantages and disadvantages. The appropriate technique for a given thermal problem depends on the situation under consideration, such as the ease of accessibility, spot size, dynamics of the situation, accuracy needed, cost of instrumentation, advancements in technology. In this paper, these techniques are briefly reviewed with pros and cons on their application for a given situation.     

An explainable deep learning model for prediction of early-stage chronic kidney disease

Chronic kidney disease (CKD) is a major public health concern with rising prevalence and huge costs associated with dialysis and transplantation. Early prediction of CKD can reduce the patient's risk of CKD progression to end-stage kidney failure. Artificial intelligence offers more intelligent and expert healthcare services in disease diagnosis. In this work, a deep learning model is built using deep neural networks (DNN) with an adaptive moment estimation optimization function to predict early-stage CKD. The health care applications require interpretability over the predictions of the black-box model to build conviction towards the model's prediction. Hence, the predictions of the DNN-CKD model are explained by the local interpretable model-agnostic explainer (LIME). The diagnostic patient data is trained on five layered DNN with three hidden layers. Over the unseen data, the DNN-CKD model yields an accuracy of 98.75% and a roc_auc score of 98.86% in detecting CKD risk. The explanation revealed by the LIME algorithm echoes the influence of each feature on the prediction made by the DNN-CKD model over the given CKD data. With its interpretability and accuracy, the proposed system may effectively help medical experts in the early diagnosis of CKD.     

Anti-methanogenic effects of monensin in dairy and beef cattle: A meta-analysis

Monensin is a widely used feed additive with the potential to minimize methane (CH₄) emissions from cattle. Several studies have investigated the effects of monensin on CH₄, but findings have been inconsistent. The objective of the present study was to conduct meta-analyses to quantitatively summarize the effect of monensin on CH₄ production (g/d) and the percentage of dietary gross energy lost as CH₄ (Y_m) in dairy cows and beef steers. Data from 22 controlled studies were used. Heterogeneity of the monensin effects were estimated using random effect models. Due to significant heterogeneity (>68%) in both dairy and beef studies, the random effect models were then extended to mixed effect models by including fixed effects of DMI, dietary nutrient contents, monensin dose, and length of monensin treatment period. Monensin reduced Y_m from 5.97 to 5.43% and diets with greater neutral detergent fiber contents (g/kg of dry matter) tended to enhance the monensin effect on CH₄ in beef steers. When adjusted for the neutral detergent fiber effect, monensin supplementation [average 32 mg/kg of dry matter intake (DMI)] reduced CH₄ emissions from beef steers by 19 ± 4 g/d. Dietary ether extract content and DMI had a positive and a negative effect on monensin in dairy cows, respectively. When adjusted for these 2 effects in the final mixed-effect model, monensin feeding (average 21 mg/kg of DMI) was associated with a 6 ± 3 g/d reduction in CH₄ emissions in dairy cows. When analyzed across dairy and beef cattle studies, DMI or monensin dose (mg/kg of DMI) tended to decrease or increase the effect of monensin in reducing methane emissions, respectively. Methane mitigation effects of monensin in dairy cows (–12 ± 6 g/d) and beef steers (–14 ± 6 g/d) became similar when adjusted for the monensin dose differences between dairy cow and beef steer studies. When adjusted for DMI differences, monensin reduced Y_m in dairy cows (–0.23 ± 0.14) and beef steers (–0.33 ± 0.16). Monensin treatment period length did not significantly modify the monensin effects in dairy cow or beef steer studies. Overall, monensin had stronger antimethanogenic effects in beef steers than dairy cows, but the effects in dairy cows could potentially be improved by dietary composition modifications and increasing the monensin dose.     

Large amplitude free vibration analysis of Timoshenko beams using a relatively simple finite element formulation

Free vibration analysis of uniform isotropic Timoshenko beams with geometric nonlinearity is investigated through a relatively simple finite element formulation, applicable to homogenous cubic nonlinear temporal equation (homogenous Duffing equation). Geometric nonlinearity is considered using von-Karman strain displacement relations. The finite element formulation begins with the assumption of the simple harmonic motion and is subsequently corrected using the harmonic balance method. Empirical formulas for the non-linear to linear radian frequency ratios, for the boundary conditions considered, are presented using the least square fit from the solutions of the same obtained for various central amplitude ratios. Numerical results using the empirical formulas compare very well with the results available from the literature for the classical boundary conditions such as the hinged–hinged, clamped–clamped and clamped–hinged beams. Numerical results for the beams with non-classical boundary conditions such as the hinged-guided and clamped-guided, hitherto not studied, are also presented.     

A new apparatus for finishing large size/large batch silicon nitride (Si3N4) balls for hybrid bearing applications by magnetic float polishing (MFP)

A new apparatus was designed and built for the finishing of large size/large batch silicon nitride (Si₃N₄) balls by magnetic float polishing (MFP) technology for hybrid bearing applications. The polishing chamber is so designed that during polishing it can self-align with the upper part of the polishing chamber connected to the spindle. In situ machining of the upper part of the chamber is performed on the machine tool in which the apparatus is located, in order to achieve high accuracy and geometric alignment of the system. The finishing methodology consists of mechanical polishing followed by chemo-mechanical polishing. Boron carbide (B₄C), silicon carbide (SiC), and cerium oxide (CeO₂) are the three abrasives used in this investigation. Three stages are involved in polishing, namely, 1. a roughing stage to remove maximum material without imparting any damage to the surface, 2. an intermediate stage of semi-finishing to control the size and improve sphericity, and 3. a final finishing stage to obtain best surface finish and sphericity while maintaining the final diameter. Taguchi method was applied for the roughing stage to optimize the polishing conditions for the best material removal rate. Level average response analysis has indicated that a load of 1.5 N/ball, an abrasive concentration of 20%, and a speed of 400 rpm would give a high material removal rate using B₄C (500 grit) abrasive. A groove is formed on the bevel of the upper part of the chamber which plays different roles, some beneficial and other not so beneficial, in each stage. In the roughing stage, it is preferable, though not essential, to machine the groove after each run to maintain high material removal rates. It is, however, necessary to remove the groove formed at the end of the roughing stage. In the intermediate or semifinishing stage, sphericity can be significantly improved by not machining the groove. Thus groove, in this case, facilitates in the improvement of sphericity. Before the beginning of the final finishing stage, machining the groove is necessary for rapid improvement in the surface finish. A batch of 46, 3/4 in. Si₃N₄ balls was finished to a final diameter of 0.7500 in. with an average sphericity of 0.25 μm (best value of 0.15 μm) and an average surface finish, Ra of 8 nm (best value of 6.7 nm) with an actual polishing time of <30 h. This technology is easy to implement in industry and does not entile high capital investment.     

Combustion characteristics of H2/N2 and H2/CO syngas nonpremixed flames

Turbulent nonpremixed H₂/N₂ and H₂/CO syngas flames were simulated using 3D large eddy simulations coupled with a laminar flamelet combustion model. Four different syngas fuel mixtures varying from H₂-rich to CO-rich including N₂ have been modelled. The computations solved the Large Eddy Simulation governing equations on a structured non-uniform Cartesian grid using the finite volume method, where the Smagorinsky eddy viscosity model with the localised dynamic procedure is used to model the sub-grid scale turbulence. Non-premixed combustion has been incorporated using the steady laminar flamelet model. Both instantaneous and time-averaged quantities are analysed and data were also compared to experimental data for one of the four H₂-rich flames. Results show significant differences in both unsteady and steady flame temperature and major combustion products depending on the ratio of H₂/N₂ and H₂/CO in syngas fuel mixture.     

Flow-Establishment Length in Rectangular Channels and Ducts

Laboratory experiments related to open channel hydraulics are generally intended to be carried out in the fully developed flow region of a rectangular flume. The developing region, in channels as well as in ducts, is a complex three-dimensional flow region influenced by secondary circulation and free surface effects, and is therefore not amenable to analytical solution. Laboratory data and a numerical model have been used to study the variation of the length of flow establishment in rectangular channels.     

Entrepreneurial universities and the dynamics of academic knowledge production: A case study of basic vs. applied research in Belgium

This paper explores issues related to the impact of Science-Industry relationships on the knowledge production of academic research groups, in particular on the alleged shift to the more applied research end under the influence of business partners' needs. Our findings from a case study of the Belgian Katholieke Universiteit Leuven ((K.U. Leuven) show a significant steady growth over time of publications produced by academic research groups involved in University-Industry linkages, closely related to factors both internal and external to the university that have stimulated academic entrepreneurial behaviour. On an aggregated level for 1985-2000, basic research publications appear to be more present than applied ones, both in total numbers and in growth rates. Our findings show that applied and basic research publications generally rose together in the same year. No clear and generalised evidence of a shift towards the applied research end determined by the involvement in U-I linkages was found, the weak indications of such a shift within groups coming only for groups that have already high applied versus basic orientation. These results suggest that the academic research groups examined have developed a record of applied publications without affecting their basic research publications and, rather than differentiating between applied and basic research publications, it is the combination of basic and applied publications that consolidate the group's R&D potential. Accordingly, critical assessments of the University side of the emerging 'Triple Helix' need to take into account the dynamic nature of the research dimension.     

Enhanced T cell engraftment after retroviral delivery of an antiviral gene in HIV-infected individuals

Intracellular expression of gene products that inhibit viral replication have the potential to complement current antiviral approaches to the treatment of AIDS. We previously have shown that a mutant inhibitory form of an essential viral protein, Rev M10, prolongs the survival of T cells transduced with a nonviral vector in HIV-infected individuals. Because these gene-modified cells were not observed in patients beyond 8 weeks, efforts were made to improve the duration of engraftment. In this study, we used retroviral vector delivery of Rev M10 to CD4(+) cells and analyzed relevant immune responses in a pilot study of three HIV-seropositive patients. DNA and RNA PCR analyses revealed that cells transduced with Rev M10 retroviral vectors survived and expressed the recombinant gene for significantly longer time periods than those transduced with a negative control vector in all three patients. Immune responses were not detected either to Rev M10 or to Moloney murine leukemia virus gp70 envelope protein. Rev M10-transduced cells were detected for an average of 6 months after retroviral gene transfer compared with approximately 3 weeks for the previously reported nonviral vector delivery. These findings suggest that retroviral delivery of an antiviral gene may potentially contribute to immune reconstitution in AIDS and could provide a more effective vector to prolong survival of CD4(+) cells in HIV infection.