Advanced Exergy Analysis of an Integrated SOFC-Adsorption Refrigeration Power System

In this chapter, an exergy analysis applied to a solid oxide fuel cell (SOFC)/vapor adsorption refrigeration (VAR) system is presented. The influences of four significant parameters (current density, inlet fuel temperature, fuel utilization and steam-to-carbon ratio) on the exergy efficiency of both the SOFC stack and the SOFC-VAR system are investigated. In order to do so, a mathematical model is constructed in Engineering Equation Solver (EES) software to generate the simulations. The analysis shows that the calculated exergy efficiency is around 8% lower than the energy efficiency for both cases. Moreover, it is found that most of the causes of irreversibilities in the system are due to electronic and ionic conduction in the components. It is also shown that the exergy efficiency is substantially sensitive to fuel inlet temperature, which is evidenced by a bending-over behavior. Finally, in accordance with the calculated efficiency defects, the main exergy destructions are present in the heat exchangers, the SOFC, the afterburner and the generator

Operando Label-free Optical Imaging of Solution-Phase Ion Transport and Electrochemistry

Ion transport is a fundamental process in many physical, chemical, and biological phenomena, and especially in electrochemical energy conversion and storage. Despite its immense importance, demonstrations of label-free, spatially and temporally resolved ion imaging in the solution phase under operando conditions are not widespread. Here we spatiotemporally map ion concentration gradient evolution in solution and yield ion transport parameters by refining interferometric reflection microscopy, obviating the need for absorptive or fluorescent labels. As an example, we use an electrochemical cell with planar electrodes to drive concentration gradients in a ferricyanide-based aqueous redox electrolyte, and we observe the lateral spatiotemporal evolution of ions via concentration-dependent changes to the refractive index. Analysis of an evolving spatiotemporal ion distribution directly yields the diffusivity of the redox-active species. The simplicity of this approach makes it amenable to probing local ion transport behavior in a wide range of electrochemical, bioelectronic, and electrophysiological systems.Comment: includes supporting informatio

An overview of refrigeration and its impact on the development in the Democratic Republic of Congo

The development of refrigeration is a priority in all countries, given the multidimensional roles that it plays in the sustainable development of society. In developing countries, efforts are being made to catch up with the delayed experienced in the use of refrigeration. To achieve this goal, several countries are allowed to trace the history of refrigeration in their countries in order to understand the main causes of non-expansion, and then set up a new strategy of sustainable development for this technology. The Democratic Republic of Congo (DRC) is a developing country that has experienced a very interesting history of refrigeration, but is still less known by the Congolese themselves as well as by scientists. This paper has traced out the outline in the history of refrigeration in the DRC. Surveys were conducted in the industrial, health, residential, commercial, and tourism sectors during the colonial and post-colonial period. Results showed that the use of refrigeration in the DRC has been remarkably observed in the industrial sector, especially in breweries, with a cooling capacity ranging from 50.1 thousand to 2.88 million kWh, about 5 659 % between 1929 and 1957; from 3 million to 26.5 million kWh, about 783.3 % between 1958 and 1980, and then dropped to 6.5 million kWh in 2004 before resuming its growth up to 11 million kWh in 2009. The variations in the use of refrigeration during the above periods significantly influenced the economy, in the sense that the economic and social indicators of the country grew from 0.415 to 0.430 between 1975 and 1985, and then declined to 0.375 in 2000, due to political instability, before rising up to 0.410 in 2005

An overview of refrigeration and its impact on the development in the Democratic Republic of Congo

The development of refrigeration is a priority in all countries, given the multidimensional roles that it plays in the sustainable development of society. In developing countries, efforts are being made to catch up with the delayed experienced in the use of refrigeration. To achieve this goal, several countries are allowed to trace the history of refrigeration in their countries in order to understand the main causes of non-expansion, and then set up a new strategy of sustainable development for this technology. The Democratic Republic of Congo (DRC) is a developing country that has experienced a very interesting history of refrigeration, but is still less known by the Congolese themselves as well as by scientists. This paper has traced out the outline in the history of refrigeration in the DRC. Surveys were conducted in the industrial, health, residential, commercial, and tourism sectors during the colonial and post-colonial period. Results showed that the use of refrigeration in the DRC has been remarkably observed in the industrial sector, especially in breweries, with a cooling capacity ranging from 50.1 thousand to 2.88 million kWh, about 5 659 % between 1929 and 1957; from 3 million to 26.5 million kWh, about 783.3 % between 1958 and 1980, and then dropped to 6.5 million kWh in 2004 before resuming its growth up to 11 million kWh in 2009. The variations in the use of refrigeration during the above periods significantly influenced the economy, in the sense that the economic and social indicators of the country grew from 0.415 to 0.430 between 1975 and 1985, and then declined to 0.375 in 2000, due to political instability, before rising up to 0.410 in 2005

Experimental assessment and semi empirical estimation of frost accretion—A case study on a spine-finned inverted-V tube array evaporator

Present work focuses on frost accretion in a spine-finned inverted-V tube array evaporator. An experimental evaluation was performed using a standard issue, vertical top-mount, 18 cubic feet, 0.5 m3, refrigerator. Evaporator temperature distribution, inner airflow velocity, and relative humidity were measured to account for convective phenomena influencing frost distribution. Frost formation and accretion on the surface of the evaporator were visualized using thermal and microscopic imagery. The images were processed using a machine vision algorithm to measure frost thickness. Complementarily, frost density and vapor mass transfer were computed using available correlations. An estimation function was derived from the compiled data using a semi empirical approach, i.e., direct measurements and thermophysical substance properties. The resulting mathematical expression estimated the frost accretion rate within an error expectancy, RMSE, of 0.1479 and displayed a goodness-of-fit, R-Squared, of 0.9029. Based on these results, semi empirical estimation, is proposed as a viable approach to construct adequate limits for new predictions, vis-à-vis evaporator performance, ultimately reducing appliance energy consumption via implementing more effective control strategies regarding internal defrosting

Empathy at Play:Embodying Posthuman Subjectivities in Gaming

In this article, we address the need for a posthuman account of the relationship between the avatar and player. We draw on a particular line of posthumanist theory associated closely with the work of Karen Barad, Rosi Braidotti and N. Katherine Hayles that suggests a constantly permeable, fluid and extended subjectivity, displacing the boundaries between human and other. In doing so, we propose a posthuman concept of empathy in gameplay, and we apply this concept to data from the first author’s 18-month ethnographic field notes of gameplay in the MMORPG World of Warcraft. Exploring these data through our analysis of posthuman empathy, we demonstrate the entanglement of avatar–player, machine–human relationship. We show how empathy allows us to understand this relationship as constantly negotiated and in process, producing visceral reactions in the intra-connected avatar–player subject as well as moments of co-produced in-game action that require ‘affective matching’ between subjective and embodied experiences. We argue that this account of the avatar–player relationship extends research in game culture, providing a horizontal, non-hierarchical discussion of its most necessary interaction

Co-designing Cards on Social Issues for Creating Educational Games

This paper presents a participatory methodology to design cards on social issues with the purpose to democratise knowledge among co-designers on the learning content of educational games. Situated on the topic of everyday sexism, the methodology has been developed through an iterative process involving two collaborative workshops, two iterations of card design and a feedback survey. Extracting findings from the workshops and the feedback gathered on the co- designed cards, this paper presents insights that could be used to inform similar studies using cards to inspire and foster reflection on social issues

New insights into perinatal testicular torsion

Perinatal testicular torsion is a relatively rare event that remains unrecognized in many patients or is suspected and treated accordingly only after an avoidable loss of time. The authors report their own experience with several patients, some of them quite atypical but instructive. Missed bilateral torsion is an issue, as are partial torsion, possible antenatal signs, and late presentation. These data are discussed together with the existing literature and may help shed new light on the natural course of testicular torsion and its treatment. The most important conclusion is that a much higher index of suspicion based on clinical findings is needed for timely detection of perinatal torsion. It is the authors’ opinion that immediate surgery is mandatory not only in suspected bilateral torsions but also in cases of possible unilateral torsions. There is no place for a more fatalistic “wait-and-see” approach. Whenever possible, even necrotic testes should not be removed during surgery because some endocrine function may be retained

Framing or Gaming? Constructing a Study to Explore the Impact of Option Presentation on Consumers

The manner in which choice is framed influences individuals’ decision-making. This research examines the impact of different decision constructs on decision-making by focusing on the more problematic decision constructs: the un-selected and pre-selected optout. The study employs eye-tracking with cued retrospective think-aloud (RTA) to combine quantitative and qualitative data. Eye-tracking will determine how long a user focuses on a decision construct before taking action. Cued RTA where the user will be shown a playback of their interaction will be used to explore their attitudes towards a decision construct and identify problematic designs. This pilot begins the second of a three phase study, which ultimately aims to develop a research model containing the theoretical constructs along with hypothesized causal associations between the constructs to reveal the impact of measures such as decision construct type, default value type and question framing have on the perceived value of the website and loyalty intentions

Reduced Exercise Tolerance and Pulmonary Capillary Recruitment with Remote Secondhand Smoke Exposure

RATIONALE: Flight attendants who worked on commercial aircraft before the smoking ban in flights (pre-ban FAs) were exposed to high levels of secondhand smoke (SHS). We previously showed never-smoking pre-ban FAs to have reduced diffusing capacity (Dco) at rest. METHODS: To determine whether pre-ban FAs increase their Dco and pulmonary blood flow (Qc) during exercise, we administered a symptom-limited supine-posture progressively increasing cycle exercise test to determine the maximum work (watts) and oxygen uptake (VO2) achieved by FAs. After 30 min rest, we then measured Dco and Qc at 20, 40, 60, and 80 percent of maximum observed work. RESULTS: The FAs with abnormal resting Dco achieved a lower level of maximum predicted work and VO2 compared to those with normal resting Dco (mean±SEM; 88.7±2.9 vs. 102.5±3.1%predicted VO2; p = 0.001). Exercise limitation was associated with the FAs' FEV(1) (r = 0.33; p = 0.003). The Dco increased less with exercise in those with abnormal resting Dco (mean±SEM: 1.36±0.16 vs. 1.90±0.16 ml/min/mmHg per 20% increase in predicted watts; p = 0.020), and amongst all FAs, the increase with exercise seemed to be incrementally lower in those with lower resting Dco. Exercise-induced increase in Qc was not different in the two groups. However, the FAs with abnormal resting Dco had less augmentation of their Dco with increase in Qc during exercise (mean±SEM: 0.93±0.06 vs. 1.47±0.09 ml/min/mmHg per L/min; p<0.0001). The Dco during exercise was inversely associated with years of exposure to SHS in those FAs with ≥10 years of pre-ban experience (r = -0.32; p = 0.032). CONCLUSIONS: This cohort of never-smoking FAs with SHS exposure showed exercise limitation based on their resting Dco. Those with lower resting Dco had reduced pulmonary capillary recruitment. Exposure to SHS in the aircraft cabin seemed to be a predictor for lower Dco during exercise