Development of a low temperature co-fired ceramic fuel processor for the micro-scale solid oxide fuel cell system

The miniaturized solid oxide fuel cells (µ-SOFCs) has become an intensively studied device for portable power generation technology due to its wide choice of hydrocarbon fuels, its high energy density and its great operation efficiency. It is being considered as a battery replacement [1]. The µ-SOFC system, which aims to provide electrical energy (≤ 10 W) at an operating temperature of ca. 550°C, consists of a fuel cell unit for the electrochemical conversion [2-3]; a fuel processing unit for the thermal start-up, fuel reforming and total oxidation of exhausts [4-5]; a system packaging that insulates the fuel cell unit from the operating temperature to the ambient as well as provides fluidic and electronic connections [6-8]; and an electronics module for regulating the power output. As a core module of the entire µ-SOFC system, various fuel processing units have been proposed and developed. Most of those modules have been based on microelectromechanical systems (MEMS), which however shows several critical limitations with regard to electrical and fluidic connections and system integration [9-10]. Here we propose a ceramic based meso-scale gas processer combined with thick film and low-temperature co-fired ceramic technology (LTCC). With an overall size of 12 × 30 × 10 mm3, the ceramic processor, made of Heraeus HeroLock 2000 LTCC materials, mainly functions as a meso-scale hotplate that has a cantilever shape to effectively decouple the heat at the hot zone produced by the start-up heater and/or exothermic fuel processing reactions from the cold zone, in which the temperature is near ambient and thus compatible with normal electrical and fluidic connections (Figure 1). Embedded cavities were integrated into the processor during the fabrication process by using a progressive lamination technique. A thick-film crack-free catalyst paste, containing rhodium-doped ceria-zirconia nanoparticles, was dispensed into the reaction chambers as packed catalytic beds for the processing reactions. An integrated thick-film platinum (Heraeus CL11-6109) heater provides the start-up energy for the exothermic reforming reaction of butane or methane as well as total oxidation reactions. Such a meso-scale monolithic ceramic reactor can carry out the gas processing in a thermally self-sustaining manner, rendering itself to be a functional packaging of the entire µ-SOFC system in the future. In this work, the fabrication process of the gas processor will be discussed in detail, and the results of the fuel processing reactions such as reforming, total oxidation and thermal start-up will be presented as well. References: [1] Bieberle-Hütter, A., Beckel, D., et al. Journal of Power Sources, 177(1), 123–130, (2008) [2] Rey-Mermet, S. and Muralt, P. Solid State Ionics, 179(27–32), 1497-1500, (2008) [3] Evans, A., Bieberle-Hütter, A., et al. Monatshefte für Chemie - Chemical Monthly, 140(9), 975–983, (2009) [4] Shao, Z., Haile, S. M., et al. Nature, 435(7043), 795–798, (2005) [5] Santis-Alvarez, A. J., Nabavi, M., et al. Energy & Environmental Science, 4(8), 3041, (2011) [6] Jiang, B., Maeder, T., Muralt, P. Proceedings, Power MEMS 2010, Leuven (BE), 2010 [7] Jiang, B., Muralt, P., et al. Sensors and Actuators B: Chemical, 175, 218–224, (2012) [8] Maeder, T., Jiang, B., et al. Proceedings, 7th International Conference on Ceramic Interconnect and Ceramic Microsystems Technologies (CICMT), San Diego (USA), 2011 [9] Hotz, N., Osterwalder, N., et al. Chemical Engineering Science, 63(21), 5193–5201, (2008) [10] Vaccaro, S., Malangone, L., Ciambelli, P. Industrial & Engineering Chemistry Research, 49(21), 10924–10933, (2010

Micro-solid oxide fuel cells running on reformed hydrocarbon fuels

Micro‐solid oxide fuel cell (micro‐SOFC) systems are predicted to have a high energy density and specific energy and are potential power sources for portable electronic devices. A micro‐SOFC system is under development in the frame of the ONEBAT project [1‐3]. In this presentation, we report on the fabrication and characterization of a sub‐system assembly consisting of a startup heater and a micro‐reformer bonded to a Si chip with electrochemically‐active micro‐SOFC membranes. A functional carrier including fluidic channels for gas feed and integrated heaters was bonded to a microreformer with an overall size of 12.7 mm x 12.7 mm x 1.9 mm [4‐7]. As a catalyst, a foam‐like material made of ceria‐zirconia nanoparticles doped with rhodium was used to fill the 58.5 mm3 reformer cavity. This micro‐reformer allows for high methane and butane conversion of > 90 % with a hydrogen selectivity of > 80 % at 550 °C in the reformer [7, 8]. A silicon chip with 30 free‐standing micro‐SOFC membranes (390 μm x 390 μm) with a thickness of less than 500 nm was bonded to the carrier‐reformer assembly described above. The micro‐SOFC membrane consisted of an yttria‐ stabilized zirconia thin film electrolyte. Both Pt‐based and ceramic‐based electrode materials were tested regarding the thermal stability and carbon poisoning at temperatures below 600 °C. The functional‐carrier mirco‐reformer micro‐SOFC assembly was electrochemically tested with hydrocarbon fuel between 300 °C and 600 °C. The fuel cell performance and the microstructural evolution of the anode are discussed as well

Micro-solid oxide fuel cells as power supply for small portable electronic equipment

Micro-solid oxide fuel cell (SOFC) systems are anticipated for powering small, portable electronic devices, such as laptop, personal digital assistant (PDA), medical and industrial accessories. It is predicted that micro-SOFC systems have a 2-4 higher energy density than Li-ion batteries [1]. However, literature mainly focuses on the fabrication and characterization of thin films and membranes for micro-SOFC systems [2-12]; the entire system approach is not yet studied in detail. We will therefore discuss in this paper the entire approach from the fabrication of thin films and membranes up to the complete system, including fuel processing, thermal management and integration

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Delayed colorectal cancer care during covid-19 pandemic (decor-19). Global perspective from an international survey

Background The widespread nature of coronavirus disease 2019 (COVID-19) has been unprecedented. We sought to analyze its global impact with a survey on colorectal cancer (CRC) care during the pandemic. Methods The impact of COVID-19 on preoperative assessment, elective surgery, and postoperative management of CRC patients was explored by a 35-item survey, which was distributed worldwide to members of surgical societies with an interest in CRC care. Respondents were divided into two comparator groups: 1) ‘delay’ group: CRC care affected by the pandemic; 2) ‘no delay’ group: unaltered CRC practice. Results A total of 1,051 respondents from 84 countries completed the survey. No substantial differences in demographics were found between the ‘delay’ (745, 70.9%) and ‘no delay’ (306, 29.1%) groups. Suspension of multidisciplinary team meetings, staff members quarantined or relocated to COVID-19 units, units fully dedicated to COVID-19 care, personal protective equipment not readily available were factors significantly associated to delays in endoscopy, radiology, surgery, histopathology and prolonged chemoradiation therapy-to-surgery intervals. In the ‘delay’ group, 48.9% of respondents reported a change in the initial surgical plan and 26.3% reported a shift from elective to urgent operations. Recovery of CRC care was associated with the status of the outbreak. Practicing in COVID-free units, no change in operative slots and staff members not relocated to COVID-19 units were statistically associated with unaltered CRC care in the ‘no delay’ group, while the geographical distribution was not. Conclusions Global changes in diagnostic and therapeutic CRC practices were evident. Changes were associated with differences in health-care delivery systems, hospital’s preparedness, resources availability, and local COVID-19 prevalence rather than geographical factors. Strategic planning is required to optimize CRC care