Parametric Study of CO₂ Methanation for Synthetic Natural Gas Production

The production of methane by carbon dioxide hydrogenation through optimization of the operating parameters to enhance methane yield and carbon dioxide conversion in a two‐stage fixed bed reactor is investigated. The influence of temperature, gas hourly space velocity (GHSV), and H2:CO2 ratio on the production of methane is studied. In addition, different methanation catalysts in terms of metal promoters and support materials are investigated to maximize methane production. The results show that the maximum methane yield and maximum carbon dioxide conversion are obtained at a catalyst temperature of 360 °C with a H2:CO2 ratio of 4:1 and total GHSV of 6000 mL h−1 g−1catalyst and reactant GHSV of 3000 mL h−1 g−1catalyst. The optimum metal‐alumina catalyst investigated for CO2 conversion and methane yield is the 10 wt%‐Ni‐Al2O3 catalyst. However, reduction in the methane yield is observed with the addition of Fe and Co promoters because of catalyst sintering and nonuniform dispersion of metals on the support. Among the different catalyst support materials studied, i.e., Al2O3, SiO2 and MCM‐41, the highest catalytic activity is shown by the Al2O3 catalyst with 83 mol% CO2 conversion, producing 81 mol% CH4 with 98% CH4 selectivity

Enhanced hydrogen-rich gas production from waste biomass using pyrolysis with non-thermal plasma-catalysis

A pyrolysis-non-thermal plasma-catalytic system for the increased production of hydrogen-rich gas from waste biomass has been investigated. Plasma processing of the hydrocarbon pyrolysis gases produced a marked increase in total gas yield with plasma-catalysis producing a further modest increase. The product gases were mainly composed of H₂ , CO and CO₂ , which were all increased under plasma and plasma-catalyst conditions. For example, H₂ yield increased from 1.0 mmol g −¹biomass in the absence of plasma to 3.5 mmol g −¹biomass with plasma and to 4.0 mmol g −¹biomass with plasma-catalysis. In addition, in the absence of plasma, the hydrocarbon tar content in the product gas was 420 mg m −³ , but, for non-catalytic plasma conditions, this was reduced to 325 mg m −³ and for plasma-catalytic steam reforming, the tar hydrocarbons were markedly reduced to 150 mg m −³ . The effect of increasing input power for the plasma processing (no catalyst) showed a large increase in total gas, H₂ , CO and CO₂ yield and corresponding decrease in hydrocarbon gas concentration. Plasma-catalysis showed that higher power input had only a small effect on gas yield. Plasma-catalysis was shown to produce lower catalyst coke deposition compared to non-plasma catalytic processing

Methane Production from the Pyrolysis–Catalytic Hydrogenation of Waste Biomass: Influence of Process Conditions and Catalyst Type

The production of methane through the optimization of various operating parameters and the use of different catalysts has been investigated using a two-stage, pyrolysis–catalytic hydrogenation reactor. Pyrolysis of the biomass in the first stage produces a suite of gases, including CO2 and CO, which undergo catalytic hydrogenation in the presence of added H2 in the second stage. The influence of the biomass pyrolysis temperature, catalyst temperature, and H2 gas space velocity has been investigated for the optimization and enhancement of the methane yield. In addition, different metal catalysts (Co/Al2O3, Mo/Al2O3, Ni/Al2O3, Fe/Al2O3), the influence of different metal loadings, catalyst calcination temperature, and different support materials (Al2O3, SiO2, and MCM-41) were investigated. The yield of methane was linked to the properties of the catalysts including the preparation calcination temperature and support material which influenced the catalyst surface area and metal crystallite particle size by sintering. The highest methane yield of 7.4 mmol g–1biomass was obtained at a final pyrolysis temperature of 800 °C, catalyst temperature of 500 °C, and H2 gas hourly space velocity of 3600 mL h–1 g–1catayst. This optimization process resulted in 75.5 vol % of methane in the output gaseous mixture

Fast Predictive Simple Geodesic Regression

Deformable image registration and regression are important tasks in medical image analysis. However, they are computationally expensive, especially when analyzing large-scale datasets that contain thousands of images. Hence, cluster computing is typically used, making the approaches dependent on such computational infrastructure. Even larger computational resources are required as study sizes increase. This limits the use of deformable image registration and regression for clinical applications and as component algorithms for other image analysis approaches. We therefore propose using a fast predictive approach to perform image registrations. In particular, we employ these fast registration predictions to approximate a simplified geodesic regression model to capture longitudinal brain changes. The resulting method is orders of magnitude faster than the standard optimization-based regression model and hence facilitates large-scale analysis on a single graphics processing unit (GPU). We evaluate our results on 3D brain magnetic resonance images (MRI) from the ADNI datasets.Comment: 19 pages, 10 figures, 13 table

Vertically mounted InGaN-on-Sapphire light-emitting diodes

An InGaN/GaN light-emitting diode (LED) chip mounted in a vertical configuration (vmLED) is demonstrated, exhibiting significant enhancement to light extraction, compared with a LED mounted in a conventional planar geometry. By flipping the chip orthogonally, two large illumination surfaces of the device are exposed for direct light extraction. Comparisons, through ray-trace modeling and experiment data with conventional surface-mounted LEDs, indicate that the vmLEDs achieve superior light extraction efficiency. A sapphire-prism-mounted vmLED is further proposed to improve heat sinking, which is well suited for higher current operations. © 2006 IEEE.published_or_final_versio

Production and application of carbon nanotubes, as a co-product of hydrogen from the pyrolysis-catalytic reforming of waste plastic

Hydrogen production from waste plastics is an important alternative for managing waste plastics. This work addresses a promising technology for co-producing high value carbon nanotubes (CNTs) in addition to the production of hydrogen; thus significantly increasing the economic feasibility of the process. Catalyst design is a critical factor to control the production of hydrogen and CNTs. NiMnAl catalysts, prepared by a co-precipitation method, with different metal molar ratios were developed and investigated using a two-stage fixed-bed reactor. It was found that the NiMnAl catalyst with the higher Mn content produced a higher yield of carbon (57.7 wt.%). Analysis of the carbon on the NiMnAl catalysts showed it to consist of ∼90 wt.% of carbon nanotubes. The CNTs were recovered from the catalyst and added at 2 wt.% to LDPE plastic to form a composite material. The tensile and flexural strength and the tensile and flexural modulus of the CNT composite material were significantly improved by the addition of the recovered CNTs. Thus it is suggested that cost-effective CNTs could be produced from waste plastics as by-product of the production of hydrogen, enhancing the potential applications of CNTs in the composite industry

A Method for Providing High-volume Interprofessional Simulation Encounters in Physical and Occupational Therapy Education Programs

With an increasing emphasis on interprofessional education within the allied health professions, simulation has potential for being a useful teaching modality for providing collaborative learning experiences for occupational and physical therapist students. However, there are many challenges associated with conducting simulations with large numbers of students. We describe the design, planning, cost, and support staff time required for conducting an interprofessional simulation of the intensive care setting, including a methodology for maximizing resources and student opportunities for participation for 64 physical and occupational therapy students over a 4-hour time period. Qualitative analyses of student experiences are also presented

Demonstration project on epilepsy in Brazil - Outcome assessment

Purpose: To assess the outcome of patients with epilepsy treated at primary care health units under the framework of the demonstration project on epilepsy in Brazil, part of the WHO/ILAE/IBE Global Campaign Against Epilepsy. Method. We assessed the outcome of patients treated at four primary health units. The staff of the health units underwent information training in epilepsy. The outcome assessment was based on: 1) reduction of seizure frequency, 2) subjective perception from the patient's and the physician's point of view, 3) reduction of absenteeism, 4) social integration (school and work), and 5) sense of independence. Results: A total of 181 patients (93 women - 51%) with a mean age of 38 (range from 2 to 86) years were studied. The mean follow-up was 26 months (range from 1 to 38 months, 11 patients had follow-up of less than 12 months). Seizure frequency was assessed based on a score system, ranging from 0 (no seizure in the previous 24 months) to 7 (> 10 seizure/day). The baseline median seizure-frequency score was 3 (one to three seizures per month). At the end of the study the median seizure-frequency score was 1 (one to three seizures per year). The patients' and relatives' opinions were that in the majority (59%) the health status had improved a lot, some (19%) had improved a little, 20% experienced no change and in 2% the health status was worse. With regard to absenteeism, social integration and sense of independence, there were some modest improvements only. Discussion: The development of a model of epilepsy treatment at primary health level based on the existing health system, with strategic measures centred on the health care providers and the community, has proved to be effective providing important reductions in seizure frequency, as well as in general well being. This model can be applied nationwide, as the key elements already exist provided that strategic measures are put forward in accordance with local health providers and managers

Pyrolysis-plasma/catalytic reforming of post-consumer waste plastics for hydrogen production

Different types of single waste plastics and a range of real-world mixed waste plastics from several different industrial and commercial sources have been processed in a pyrolysis-plasma/catalytic experimental reactor system for the production of hydrogen. The hydrocarbons produced from the pyrolysis stage were catalytically (Ni/MCM-41) steam reformed in a low temperature, non-thermal plasma/catalytic reactor. The polyolefin plastics, high density polyethylene, low density polyethylene and polypropylene produced the highest yield of hydrogen at 18.0, 17.3 and 16.3 mmol g−1plastics respectively. The aromatic structured polystyrene produced a lower hydrogen yield of 11.9 mmol g−1plastics and polyethylene terephthalate with an aromatic and oxygenated structure produced only 10.2 mmol g−1plastics and a high yield of carbon oxide gases. The real-world mixed plastic waste produced yields of hydrogen in the range of 13.4–16.9 mmol g−1plastics. The lowest hydrogen yield of 13.4 mmol g−1plastics was produced from the mineral water bottle packaging waste due to the high content of polyethylene terephthalate in the plastic waste mixture

Pyrolysis-catalytic steam reforming of waste plastics for enhanced hydrogen/syngas yield using sacrificial tire pyrolysis char catalyst

Pyrolysis-catalytic steam reforming of waste plastics to produce hydrogen-rich syngas has been investigated using tire char as a sacrificial catalyst in a two-stage pyrolysis-catalytic steam reforming reactor system. The simultaneous steam reforming of the pyrolysis volatiles and ‘sacrificial’ steam gasification of tire char increased the overall yield of syngas and hydrogen in the gas products. Manipulating the catalyst temperature, steam input, char catalyst:plastic ratio influenced hydrogen yield. The presence of metals such as Zn, Fe, Ca and Mg in tire char, play a catalytic role in steam reforming reactions. The syngas production achieved when the catalyst temperature was 1000 °C and steam weight hourly space velocity was 8 g h−1 g−1 catalyst was 135 mmol H2 g-1plastic and 92 mmol CO g-1plastic. However, increasing the amount of char catalyst (4:1 char catalyst:plastic ratio) enabled hydrogen yields of 211 mmol g-1plastic and total syngas yields of 360 mmol g-1plastic to be achieved