43 research outputs found

    Gasification of biomass in supercritical water, challenges for the process design—lessons learned from the operation experience of the first dedicated pilot plant

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    Gasification of organic matter under the conditions of supercritical water (T > 374 °C, p > 221 bar) is an allothermal, continuous flow process suitable to convert materials with high moisture content (<20 wt.% dry matter) into a combustible gas. The gasification of organic matter with water as a solvent offers several benefits, particularly the omission of an energy-intensive drying process. The reactions are fast, and mean residence times inside the reactor are consequently low (less than 5 min). However, there are still various challenges to be met. The combination of high temperature and pressure and the low concentration of organic matter require a robust process design. Additionally, the low value of the feed and the product predestinate the process for decentralized applications, which is a challenge for the economics of an application. The present contribution summarizes the experience gained during more than 10 years of operation of the first dedicated pilot plant for supercritical water gasification of biomass. The emphasis lies on highlighting the challenges in process design. In addition to some fundamental results gained from comparable laboratory plants, selected experimental results of the pilot plant “VERENA” (acronym for the German expression “experimental facility for the energetic exploitation of agricultural matter”) are presented

    Linking internal marketing with customer outcomes

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    Purpose – The purpose of this study is to explore how the adoption of an internal marketing (IM) programme in a retail banking setting enhances some positive employee behaviours that promote customer perceived service quality. Design/methodology/approach – A multilevel research design is adopted which draws evidence from branch managers, employees and customers in order to investigate whether branch manager’s adoption of an IM philosophy affects front-line employee responsiveness to the firm’s IM strategies and their levels of motivation, empowerment and organizational identification (OI), respectively. Findings – Results indicate that manager’s IM adoption can enhance employee adoption of IM and raises their levels of motivation, empowerment and OI. The moderating role of manager-employee dissimilarity is also discussed. Finally, findings confirm that employee motivation, empowerment and OI affect customer perceptions of service quality. Originality/value – This study provides an important shift by formally including IM into multilevel marketing research and establishes another link in the IM-organizational performance relationship, uncovering some behavioural routes through which the positive effects of IM can add to the achievement of firm’s external marketing objectives

    Formic Acid Formation by ClostridiumClostridium ljungdahliiljungdahlii at Elevated Pressures of Carbon Dioxide and Hydrogen

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    Low productivities of bioprocesses using gaseous carbon and energy sources are usually caused by the low solubility of those gases (e.g., H2 and CO). It has been suggested that increasing the partial pressure of those gases will result in higher dissolved concentrations and should, therefore, be helpful to overcome this obstacle. Investigations of the late 1980s with mixtures of hydrogen and carbon monoxide showed inhibitory effects of carbon monoxide partial pressures above 0.8 bar. Avoiding any effects of carbon monoxide, we investigate growth and product formation of Clostridium ljungdahlii at absolute process pressures of 1, 4, and 7 bar in batch stirred tank reactor cultivations with carbon dioxide and hydrogen as sole gaseous carbon and energy source. With increasing process pressure, the product spectrum shifts from mainly acetic acid and ethanol to almost only formic acid at a total system pressure of 7 bar. On the other hand, no significant changes in overall product yield can be observed. By keeping the amount of substance flow rate constant instead of the volumetric gas feed rate when increasing the process pressure, we increased the overall product yield of 7.5 times of what has been previously reported in the literature. After 90 h of cultivation at a total pressure of 7 bar a total of 4 g L−1 of products is produced consisting of 82.7 % formic acid, 15.6 % acetic acid, and 1.7 % ethanol

    Gasification of Biomass in Supercritical Water, Challenges for the Process Design—Lessons Learned from the Operation Experience of the First Dedicated Pilot Plant

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    Gasification of organic matter under the conditions of supercritical water (T &gt; 374 °C, p &gt; 221 bar) is an allothermal, continuous flow process suitable to convert materials with high moisture content (&lt;20 wt.% dry matter) into a combustible gas. The gasification of organic matter with water as a solvent offers several benefits, particularly the omission of an energy-intensive drying process. The reactions are fast, and mean residence times inside the reactor are consequently low (less than 5 min). However, there are still various challenges to be met. The combination of high temperature and pressure and the low concentration of organic matter require a robust process design. Additionally, the low value of the feed and the product predestinate the process for decentralized applications, which is a challenge for the economics of an application. The present contribution summarizes the experience gained during more than 10 years of operation of the first dedicated pilot plant for supercritical water gasification of biomass. The emphasis lies on highlighting the challenges in process design. In addition to some fundamental results gained from comparable laboratory plants, selected experimental results of the pilot plant “VERENA” (acronym for the German expression “experimental facility for the energetic exploitation of agricultural matter”) are presented

    Automated sleep breath disorders detection utilizing patient sound analysis

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    Results of clinical studies suggest that there is a relationship between breathing-related sleep disorders and behavioral disorder and health effects. Apnea is considered one of the major sleep disorders with great accession in population and significant impact on patient's health. Symptoms include disruption of oxygenation, snoring, choking sensations, apneic episodes, poor concentration, memory loss, and daytime somnolence. Diagnosis of apnea and breath disorders involves monitoring patient's biosignals and breath during sleep in specialized clinics requiring expensive equipment and technical personnel. This paper discusses the design and technical details of an integrated low-cost system capable for preliminary detection of sleep breath disorders at patient's home utilizing patient sound signals. The paper describes the proposed architecture and the corresponding HW and SW modules, along with a preliminary evaluation. (C) 2012 Elsevier Ltd. All rights reserved
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