The effect of flow field design on the degradation mechanisms and long term stability of HT-PEM fuel cell

Philosophiae Doctor - PhDFuel cells are long term solution for global energy needs. In current fuel cell technologies, Proton Exchange Membrane (PEM) fuel cells are known for quick start-up and ease of operation compared to other types of fuel cells. Operating PEM fuel cells at high temperature show promising applications for stationary combined heat and power application (CHP). The high operating temperature up to 160°C allows waste heat to be recovered for co-generation or tri-generation purposes. The commercially available PEM fuel cells operating at 160⁰C can tolerate up to 3% CO without significant loss of performance, making HT-PEM fuel cell viable choice when reformate is used. In reality these advantages convert to very little balance-of-plant compared to Nafion® based fuel cells operating at 60°C. However, there are some problems that prevent high temperature fuel cells from large scale commercialization. The cathode is said to have sluggish reaction kinetics and high cell potentials and operating temperature during fuel cell start-up may cause severe degradation. The formation of liquid water during the shut-down can cause the phosphoric acid to leach from the cell during operation. Efforts are being made to reduce the cost and increase the durability of fuel cell components (such as catalyst and membrane) at high temperatures. Apart from degradation issues, the problems are related to cost and performance. The performance of the PEM fuel cells depends on a lot of factors such as fuel cell design and assembly, operating conditions and the flow field design used on the cathode and anode plates. The flow field geometry is one important factor influencing the performance of fuel cells. The flow fields have significant effect on pressure and flow distribution inside the fuel cell. A homogeneous distribution of the reactant gases over the active catalyst surface leads to improved electrochemical reactions and thus enhances the performance of the fuel cell. So, the design of flow fields is one of the important issues for performance improvement of PEM fuel cell in terms of power density and efficiency. There are different types of flow fields available for PEM fuel cells such as serpentine, pin, interdigitated and straight flow fields but the most obvious choice is multiple serpentine. The same can be used for high temperature PEM fuel cell (HT-PEMFC) application with ease because of absence of liquid water during the high temperature operation and no need for complex water management

METHOD TO IMPROVE LINK BRING-UP TIME FOR HIGH-SPEED ETHERNET BACKPLANE AND COPPER CABLES

Modern Massively Scalable Datacenters (MSDCs) delivering high availability software such as Software-as-a-Service (SaaS), Infrastructure-as-a-Service, etc. have stringent metrics to which to adhere. Link availability is one such crucial factor. Techniques presented herein may facilitate decreasing link bring-up time by maintaining a cache for link training (LT) transmit (TX) Finite Impulse Response (FIR) settings. Thus, these techniques may provide for faster link bring-up, faster convergence, and faster fabric module bring-up in an End of Rack (EoR) chassis. Using techniques presented herein, faster link bring-up may become the norm rather than the exception

Jejunal intussusception in an adult due to small intestine lipomatosis: a case report and review of literature

Intussusception is rare in adults. Benign neoplasm are common causes for intussusception in adults, lipoma is the commonest. Lipomas are usually solitary but 5% are multiple. Lipomatosis of small bowel is rare condition and presenting, as intestinal obstruction is even rarer. A 55 year old male patient presented with pain abdomen, distention and constipation. CECT revealed intussusception due to multiple lipomas of jejunum causing jejunojejunal intussusception. On exploratory laparotomy bowel was gangrenous and hence a resection and anastomosis was done. On 12 months fallow up patient was normal. First described by Helmstrom in 1906. Fat deposition in intestine are classified as isolated lipoma, multiple lipomas, nodular lipomatosis and diffuse fatty infiltration of wall without projecting into lumen. Usually present as malena or intussusception, volvulus. Radiologically identified by “pseudo kidney sign” and “target sign”. Reduction should not be attempted in the signs of ischemia or malignancy. Lipomatosis should kept in mind as one of the cause for intussusception in adults and CECT is the best modality to ascertain the nature of lesion in most of the cases

Impact of the Skill Shortage on the Construction Supply Chain Performance in Australia

The purpose of this paper is to investigate how the skill shortage impacts the performance of the construction supply chain in Australia. The study has adopted a quantitative research method. The quantitative data were collected by conducting a survey of employees who work in construction companies in Australia. A regression analysis was used to analyze the data from 113 respondents. The findings of the study reveal that the construction sector in Australia has high labour costs, but workers are still thinking they are not getting paid enough and cannot invest more in themselves to improve their skills. There is a lack of academic and vocational training programs offered to them. Insufficient recruitment and incentive policies are also main barriers to attract talents to the construction industry in Australia. The situation became more serious during the COVID-19 period due to the lockdowns, lack of skilled migrants, and Government working visa policies. The study implies that firms should have a deeper understanding of the reasons for the skill shortage. Firms also need to devise strategies for hiring the right talent. Further, it was found that quality talent can come from the local or foreign markets. More effective selection criteria should be designed so that the best-fit approach can be implemented. Doi: 10.28991/CEJ-2023-09-02-08 Full Text: PD

MACHINE LEARNING ASSISTED QUICK EYESCAN (MLAQE) FOR SIGNAL INTEGRITY CHECK

Presented herein is a quick scan method for signal integrity checks through sampling of four points under certain thermal condition. The techniques presented herein use a machine learning trained model to ensure signal integrity check fidelity

Germline-focused analysis of tumour-detected variants in 49,264 cancer patients: ESMO Precision Medicine Working Group recommendations

Germline; Tumour-only sequencingLínia germinal; Seqüenciació només de tumorsLínea germinal; Secuenciación solo de tumorsBackground The European Society for Medical Oncology Precision Medicine Working Group (ESMO PMWG) was reconvened to update its 2018/19 recommendations on follow-up of putative germline variants detected on tumour-only sequencing, which were based on an analysis of 17 152 cancers. Methods We analysed an expanded dataset including 49 264 paired tumour-normal samples. We applied filters to tumour-detected variants based on variant allele frequency, predicted pathogenicity and population variant frequency. For 58 cancer-susceptibility genes, we then examined the proportion of filtered tumour-detected variants of true germline origin [germline conversion rate (GCR)]. We conducted subanalyses based on the age of cancer diagnosis, specific tumour types and ‘on-tumour’ status (established tumour-gene association). Results Analysis of 45 472 nonhypermutated solid malignancy tumour samples yielded 21 351 filtered tumour-detected variants of which 3515 were of true germline origin. 3.1% of true germline pathogenic variants were absent from the filtered tumour-detected variants. For genes such as BRCA1, BRCA2 and PALB2, the GCR in filtered tumour-detected variants was >80%; conversely for TP53, APC and STK11 this GCR was <2%. Conclusion Strategic germline-focused analysis can prioritise a subset of tumour-detected variants for which germline follow-up will produce the highest yield of most actionable true germline variants. We present updated recommendations around germline follow-up of tumour-only sequencing including (i) revision to 5% for the minimum per-gene GCR, (ii) inclusion of actionable intermediate penetrance genes ATM and CHEK2, (iii) definition of a set of seven ‘most actionable’ cancer-susceptibility genes (BRCA1, BRCA2, PALB2, MLH1, MSH2, MSH6 and RET) in which germline follow-up is recommended regardless of tumour type.This work was supported by the European Society for Medical Oncology (no grant number)

Germline-Focused Analysis of Tumour-Only Sequencing: Recommendations from the ESMO Precision Medicine Working Group.

It is increasingly common in oncology practice to perform tumour sequencing using large cancer panels. For pathogenic sequence variants in cancer susceptibility genes identified on tumour-only sequencing, it is often unclear whether they are of somatic or constitutional (germline) origin. There is wide-spread disparity regarding both the extent to which systematic 'germline-focused analysis' is performed upon tumour sequencing data and for which variants follow-up analysis of a germline sample is performed. Here we present analyses of paired sequencing data from 17,152 cancer samples, in which 1494 pathogenic sequence variants were identified across 65 cancer susceptibility genes. From these analyses, the European Society of Medical Oncology Precision Medicine Working Group Germline Subgroup have generated (i) recommendations regarding germline-focused analyses of tumour-only sequencing data, (ii) indications for germline follow-up testing and (iii) guidance on patient information-giving and consent

Insights on the mixtures of imidazolium based ionic liquids with molecular solvents

The properties of ionic liquid (1-ethyl-3-methylimidazolium BF4 and 1-butyl-3-methylimidazolium BF4) + solvents (water, ethylene glycol or dimethylformamide) mixtures are studied in the full composition range as a function of mixture composition and temperature. These mixed fluids are characterized by selected physical properties and microscopic studies using density functional theory and molecular dynamics simulations. The reported results showed large non-ideal mixtures, which are caused by strong anion (BF4) – molecular solvent hydrogen bonding. Likewise, the interaction of ions, evolves from anion-cation pairs solvated by molecular solvents, for mixtures rich in molecular solvent, to large ionic aggregates for ionic liquid rich mixtures separated by a transitional composition regime. The large non-linearity of the evolution of microscopic properties with mixture composition is the origin of macroscopic thermodynamic deviations from ideality.Junta de Castilla y León (Spain, project BU324U14

Bakhtin’s chronotope, connotations, & discursive psychology: Towards a richer interpretation of experience

YesIn this paper, we draw on the Bakhtinian concept of chronotope to make the theoretical argument that the turn to embodiment can be supplemented through a consideration of connotation in discursive psychology. We use Billig’s conception of linguistic repression as a test-case as to how connotation can supplement discursive analysis, but using our own interview material to do so. From establishing the case that connotation, understood through the lens of chronotope, is potentially of vital interest to discursive psychology, we move to drawing out three implications for this for doing qualitative research differently. First of all, we suggest that researchers need to feel the chronotope of the interview to manage its connotations in vivo. Secondly, we draw attention to the role of the absent other in everyday speech and how this absent other can be analysed differently to a typical discourse analysis - as layering connotations into speech. Finally, we draw attention to the hermeneutic attitude of earnest irony when doing research as a further means of generating as well as managing connotations