An improved tri-reforming based methanol production process for enhanced CO2 valorization

The consistent rise of CO₂ concentration in the atmosphere is known to be significantly detrimental to the environment. Thus, mitigating CO₂ has become an urgent necessity. Current methods involving CO₂ mitigation can be broadly divided into two major categories which involve (i) CO₂ capture and sequestration (CCS) and (ii) CO₂ capture and valorization. Since, production of fuels/chemicals is an added feature along with mitigation in CO₂ valorization based methods, they could be economically favorable. An energy intensive CO₂ capture step is a common drawback of most CO₂ valorization methods that aim to mitigate CO₂ from major CO₂ emission sources (such as industrial flue gases). In this paper we employ and analyze a relatively new process called tri-reforming [1,2] which was developed to directly convert power plant based flue gases to synthesis gas, while avoiding the capture step. This paper is presented as an improvement over a tri-reforming coupled methanol production process as developed by Zhang et al. [3]. The process in Zhang et al. [3] involves utilizing tri-reforming process using flue gas and methane to produce synthesis gas which is then converted to methanol in the next step. The main contributions of this paper to the tri-reforming coupled methanol production process are: (i) proposition of a high pressure tri-reforming step to limit capital costs of the process (ii) establishment of steam input coupled with water separation step as a process improvement whose impact is shown to further amplify at higher tri-reformer pressures. The paper evaluates the process in terms of the profit generating and CO₂ valorization potential of the process as reflected by two parameters, gross margin (GM) and NPCV (net percentage of CO₂ valorized) respectively. In the proposed approach, higher pressures were utilized in the tri-reforming process to ensure economic feasibility of the process by limiting the reactor volume. The process improvements for the flowsheet containing the steam input combined with water separation (SWS) step over the one without these steps (termed as WSWS) are demonstrated in terms of an increase in GM/NPCV values at various pressures. The results indicate substantial improvements in GM and NPCV values (especially at higher tri-reformer pressures) ranging from 24.30 to 84.96% and 28.80–78.44% respectively in SWS cases over WSWS cases at various pressures. The simulations have been carried out in Aspen Plus V8.4 and are optimized using sensitivity analysis.     

Impacts of user-selfishness on cooperative content caching in social wireless networks

Cooperative caching can be an effective mechanism for reducing electronic content provisioning cost in Social Wireless Networks (SWNETs). These networks are formed by a collection of mobile data enabled devices physically gathering in settings such as university campus, malls, airport and other public places. In this paper, we first propose an optimal collaborative object caching policy in order to minimize the object provisioning cost in SWNETs with homogenous user requests and a peer-rebate model for promoting collaboration. Then using an analytical model we study the impacts of user selfishness on the provisioning cost and the earned rebate when certain nodes in an SWNET selfishly deviate from the optimal policy. User selfishness is motivated in order to either increase individually earned rebate or to reduce content provisioning cost. The analytical model is validated by experimental results from simulated SWNETs using the network simulator ns2.     

Secure image encryption scheme using high efficiency word-oriented feedback shift register over finite field

Multimedia Tools and Applications - Image encryption is an evolving technique in the arena of data communication. In the last decade, many encryption schemes have been suggested. Unfortunately,...     

Cyclic ammonium salts of dithiocarbamic acid: stable alternative reagents for the synthesis of S-alkyl carbodithioates from organyl thiocyanates in water

Carbodithioate esters are important functional organosulfur compounds widely used in diverse fields such as pharmaceuticals, agrochemicals and material sciences. Common preparative methods include reaction of alkyl halides, carbon disulfide and bases under both metal-free and metal-catalyzed conditions. However, organyl thiocyanates have not been previously explored, possibly because of their conversion to organyl disulfides under basic conditions. Here, we report an efficient and practical method for the preparation of libraries of carbodithioate esters from organyl thiocyanates by reacting with cyclic amine-based dithiocarbamic acid salts in water. The protocol is found to be applicable in general to various thiocyanates such as benzyl/aroyl methyl/cinnamyl and so on. Other notable features include no by-products such as disulfides, metal- and alkali-free, aqueous conditions, and finally easy and near-quantitative formation of cyclic amine-based dithiocarbamic acid salt as a stable alternative reagent.     

Systematic approach for modeling methanol mass transport on the anode side of direct methanol fuel cells

A systematic method for modeling direct methanol fuel cells, with a focus on the anode side of the system, is advanced for the purpose of quantifying the methanol crossover phenomenon and predicting the concentration of methanol in the anode catalyst layer of a direct methanol fuel cell. The model accounts for fundamental mass transfer phenomena at steady state, including convective transport in the anode flow channel, as well as diffusion and electro-osmotic drag transport across the polymer electrolyte membrane. Experimental measurements of methanol crossover current density are used to identify five modeling parameters according to a systematic parameter estimation methodology. A validation study shows that the model matches the experimental data well, and the usefulness of the model is illustrated through the analysis of effects such as the choice fuel flow rate in the anode flow channel and the presence of carbon-dioxide bubbles.     

Comparing Ocular Parameters for Cognitive Load Measurement in Eye-Gaze-Controlled Interfaces for Automotive and Desktop Computing Environments

Eye-gaze tracking is traditionally used to analyze ocular parameters for investigating visual psychology, marketing study, behavior analysis, and so on. Currently, eye-gaze trackers are also being used to control electronic interfaces in assistive technology, automobile control, and even consumer electronic products like smartphones and tablets. However, there are not many attempts to combine these two streams of research on active and passive uses of eye-gaze trackers. This article compares a few ocular parameters to estimate users’ cognitive load in eye-gaze-controlled interfaces. It was found that average velocity of a particular type of microsaccadic eye movement called Saccadic Intrusion is most indicative of users’ cognitive load compared to pupil dilation and eye-blink-based parameters. Results from the study can be used to develop new metrics of cognitive load measurement, as well as to design intelligent gaze-controlled interfaces that respond to users’ cognitive load.     

Eco-efficiency analysis for remote area power supply selection in Western Australia

Clean Technologies and Environmental Policy - Remote area power supply (RAPS) systems in Western Australia account for more than 56% of total off-grid electricity supply in Australia and utilise...