The performances of thermal-concentrated solar thermoelectric generators (TEGs) at three different geometric types are investigated numerically to aid in designing practical devices. The ...temperature-dependent properties of the commercial thermoelectric material are taken into account, and an equivalent model based on the three-dimensional finite element scheme is developed to simplify and accelerate simulations. The constriction thermal resistance and thermal spreading resistance are considered in the equivalent model. Increasing substrate area increases the thermal concentration ratio; this improves the performance of the solar TEG. In the three geometric types, the smallest element with the substrate area of 90 x 90 mm super(2) provides the maximum system efficiency of 4.15%. For a TEG at a given element length, decreasing the cross-sectional area of the thermoelectric element is a feasible route to improve the performance. Under the situation of forced convection, varying convection heat transfer coefficient has an ignorable effect on the performance. For equal convective heat transfer coefficients, water cooling is better than air cooling for the net output power of the TEG because of its increased specific heat. Therefore, water cooling is recommended for the cooling of the solar TEG.
► Gasification phenomena of raw bamboo, torrefied bamboo, and coal are studied. ► The carbon conversions of the three fuels are higher than 90%. ► The coal gas efficiency is sensitive to the type of ...fuel. ► The gasification performance of torrefied bamboo is enhanced and closer to that of coal. ► With optimum operation, syngas formation from torrefied biomass is amplified by 88%.
Gasification of torrefied biomass is a promising technique for producing synthesis gas (syngas) of higher quality than has previously been available. In this study, in order to evaluate the potential of the technique, gasification processes for three different materials, which include raw bamboo, torrefied bamboo (at 280°C for 1h), and high-volatile bituminous coal in an entrained-flow gasifier using O2 as the gasification agent, are studied numerically and compared to each other. The obtained results suggest that in all cases, the carbon conversions of the three fuels are higher than 90%. However, the cold gasification efficiency for raw bamboo is low, mainly due to the relatively lower calorific value of the material. In the case of the torrefied bamboo fuel, the gasification performance is enhanced significantly and is quite similar to the coal gasification under the same conditions. It appears that the optimum oxygen-to-fuel mass flow ratios for the gasification of raw bamboo, torrefied bamboo, and coal are 0.9, 0.7, and 0.7, and their equivalence ratios are 0.692, 0.434, and 0.357, respectively. Under optimum conditions with respect to the equivalence ratio, the cold gas efficiency of torrefied bamboo is improved by 88%, as compared to raw bamboo.
Commercially available thermoelectric modules are useful devices to recover low-temperature waste heat for power generation. To understand the characteristics of power generation from thermoelectric ...modules (TEMs), the performances of TEMs at various flow patterns, heating temperatures, flow rates of water and numbers of modules in series are studied experimentally. The results show that the effects of flow pattern of heat sink and water flow rate on the performance are not significant, but the heat source or heating temperature plays an important role. Therefore, a lower water flow rate is suggested to save power, whereas a higher hot-side temperature which leads to a larger temperature difference is recommended to give better performances of TEMs. Increasing number of modules in series provide higher output power. However, the performance of the modules in series cannot be simply predicted using linear superposition due to the Peltier effect and the non-uniformity of every module. The feature of a thermoelectric generator (TEG) is also examined and compared with the TEMs. It is found that TEM is a better choice for power generation from recovering waste heat if the temperature of a system is below 150 °C.
► A numerical method is developed to predict coal gasification phenomena. ► Particular emphasis is placed on the influence of injection pattern upon syngas production. ► The parameter of steam/coal ...ratio is also taken into account. ► The appropriate injection for the performance of coal gasification is suggested. ► The obtained results have provided a useful insight into the operation of coal gasification.
Gasification plays an important role in the development of clean coal technology. To seek appropriate operations for synthesis gas (syngas) formation, the present study develops a numerical method to predict coal gasification phenomena in an entrained-flow gasifier. Particular emphasis is placed on the influence of injection pattern upon syngas production. The parameter of steam/coal ratio is also taken into account to evaluate its impact on hydrogen generation. The simulations suggest that the developed numerical method is able to provide an accurate prediction on syngas formation. With oxygen injected from the center inlet and coal from the middle ring inlet of the reactor, the operating pattern gives the best performance of coal gasification where the carbon conversion (CC) and coal gas efficiency (CGE) are 89% and 72%, respectively. Increasing steam into the reactor reduces CC and less CO is generated. Nevertheless, more H2 is produced stemming from water gas shift reaction. This results in slight variation in CGE with altering steam/coal ratio. The obtained results have provided a useful insight into the operation of fuel and oxidant injection for coal gasification.
Evaluation and feedback of hand hygiene (HH) compliance are important elements of the WHO multimodal strategy for hospital infection control. Overt observation is recommended, but it may be ...confounded by Hawthorne effect. Covert observation offers the opportunity to decrease observer bias. In this study we conducted a one year hospital-wide HH promotion program that included medical students (MS) as covert observers.
HH compliance for the five WHO indications was determined by trained and validated observers. The overt observers consisted of eleven infection control nurses (ICNs) and two unit HH ambassadors (UAs) in each of 83 wards. The covert observers consisted of nine MS during their rotating clinical clerkships. Feedback was provided to department heads and staff each quarter.
Of the 23,333 HH observations 76.0% were by MS, 5.3% by ICNs and 18.7% by UAs. The annual compliance rates were MS 44.1%, ICNs 74.4% and UAs 94.1%; P<0.001. The MS found significantly lower annual compliance rates for 4/5 HH indications compared to ICNs and UAs; P<0.05. The ICNs reported significantly improvement from the first to the fourth quarter; P<0.001. This was associated with feedback from the MS of very poor compliance by nurses during the first quarter.
Based on these findings we recommend a two-pronged approach to HH programs. The role of ICNs and UAs is to educate, serve as role models, establish, sustain good HH practices and provide direct feedback. The role of the covert observers is to measure compliance and provide independent feedback.
•Taguchi method is employed to optimize co-gasification.•Torrefied biomass (eucalyptus) and coal are co-gasified in an entrained flow gasifier.•Cold gas efficiency is adopted as the index of the ...performance of co-gasification.•O/F ratio is the most important factor in determining co-gasification.•Optimized cold gas efficiency and carbon conversion are 80.99% and 94.51%, respectively.
This study employs the Taguchi method to approach the optimum co-gasification operation of torrefied biomass (eucalyptus) and coal in an entrained flow gasifier. The cold gas efficiency is adopted as the performance index of co-gasification. The influences of six parameters, namely, the biomass blending ratio, oxygen-to-fuel mass ratio (O/F ratio), biomass torrefaction temperature, gasification pressure, steam-to-fuel mass ratio (S/F ratio), and inlet temperature of the carrier gas, on the performance of co-gasification are considered. The analysis of the signal-to-noise ratio suggests that the O/F ratio is the most important factor in determining the performance and the appropriate O/F ratio is 0.7. The performance is also significantly affected by biomass along with torrefaction, where a torrefaction temperature of 300°C is sufficient to upgrade eucalyptus. According to the recommended operating conditions, the values of cold gas efficiency and carbon conversion at the optimum co-gasification are 80.99% and 94.51%, respectively.
Background Environmental cleaning is essential in reducing microbial colonization and health care–associated infections in hospitals. However, there is no consensus for the standard method to assess ...hospital cleanliness, and comparisons of newer methodology, such as adenosine triphosphate bioluminescence assay, with the traditional methods are limited. Methods A prospective study was conducted at a medical center between January 2013 and August 2013. In each selected room, 10-12 high-touch surfaces were sampled before and after terminal cleaning. The adequacy of cleaning was evaluated by visual inspection, aerobic colony counts (ACCs), and adenosine triphosphate (ATP) bioluminescence assay. Results Eighty-five environmental surfaces from 8 rooms were evaluated by all 3 methods. The overall inadequacy defined by visual inspection, ACC, and ATP level was 11.8%, 20.0%, and 50.6% before cleaning and 4.7%, 5.9%, 21.2% after cleaning, respectively. A correlation between the ACC and ATP was found ( r = 0.285, P < .001) using log10 values. Using ACCs <2.5 colony forming units/cm2 as the cutoff for cleanliness, the ATP assay had better sensitivity than visual inspection (63.6% vs 27.3%). The receiver operating characteristics of the ATP assay indicated that the optimal ATP cutoff value was estimated to be 5.57 relative light units/cm2. Conclusion ATP bioluminescence assay is a sensitive and rapid tool in evaluating the quality of terminal cleaning. We emphasize the value of using a quantitative method to monitor environmental cleaning at hospitals.
MicroRNAs (miRNAs) are critical regulators responding to acute environmental stresses in both plants and animals. By modulating gene expression, miRNAs either restore or reconstitute a new expression ...program to enhance cell tolerance to stresses. Cold shock is one of the stresses that can induce acute physiological responses and transcriptional changes in aquatic creatures. Previous genomic studies have revealed many cold-affected genes in fish larvae and adults, however, the role of miRNAs in acute cold response is still ambiguous. To elucidate the regulatory roles of miRNAs in the cold-inducible responses, we performed small RNA-seq and RNA-seq analyses and found potential cold regulatory miRNAs and genes. We further investigated their interactions and involvements in cold tolerance.
Small RNA-seq and RNA-seq identified 29 up-/26 down-regulated miRNAs and 908 up-/468 down-regulated genes, respectively, in responding to cold shock for 4 h at 18 °C. miRNA and transcriptomic analyses showed these miRNAs and mRNAs are involved in similar biological processes and pathways. Gene ontology enrichment analyses revealed the cold-induced genes were enriched in pathways, including melanogenesis, GnRH pathway, circadian rhythm, etc. We were particularly interested in the changes in circadian clock genes that affect daily metabolism. The enrichment of circadian clock genes was also observed in previous fish cold acclimation studies, but have not been characterized. To characterize the functional roles of circadian clock genes in cold tolerance, we individually overexpressed selected clock genes in zebrafish larvae and found one of the core clock genes per2 resulted in better recovery from cold shock. In addition, we validated the interaction of per2 with its associate miRNA, dre-mir-29b, which is also cold-inducible. It suggests the transcription of per2 can be modulated by miRNA upon cold shock.
Collectively, our observations suggest that miRNAs are fine turners for regulating genomic plasticity against cold shock. We further showed that the fine tuning of core clock gene per2 via its associated miRNA, dre-mir-29b, can enhance the cold tolerance of zebrafish larvae.
Objectives
To explore the trends in Fournier's gangrene (FG) incidence and mortality rate in Taiwan and to investigate the contributing factors to such changes.
Methods
Between 2002 and 2016, ...hospitalized FG patients who underwent subsequent surgical intervention were included in this retrospective study. Incidence, outcomes, age‐adjusted Charlson Comorbidity Index (ACCI), hospitalization cost, surgical timing, and the number of multidisciplinary specialists involved in the first‐line management of FG in each year were collected. Simple linear regression and Pearson correlation coefficient (r) were used for the subsequent analysis.
Results
The national cohort enrolled 2183 FG patients from 2002 to 2016 in Taiwan. The age‐standardized incidence rate of FG was between 0.4 and 0.8 per 100 000 population, and overall mortality was 7.8% in these 15 years. We illustrated the downward trendline of FG mortality with a 0.62 coefficient of determination. The mortality of FG patients who underwent surgery within 24 h and after 24 h were found to be 8.3 ± 3.9% and 14.6 ± 25.2%, respectively (p = 0.02). The numbers of urologists, anesthesiologists, emergency doctors, and physicians per 100 000 population had a strong negative linear correlation with FG mortality (r = 0.8, p < 0.001). ACCI score had a moderate linear relationship with FG mortality (r = 0.57, p = 0.027). The hospitalization cost showed a weak linear correlation with FG mortality (r = −0.03, p = 0.92).
Conclusions
We demonstrated the downward trend of the FG mortality rate in Taiwan from 2002 to 2016. Besides underlying comorbidities and surgical timing, sufficient multidisciplinary specialists are essential for the survival benefit of FG patients in Taiwan experience.
The fatality rate of scrub typhus infection with septic shock is quite high if timely and correct diagnosis and treatment are not obtained. There are few studies in the literature on the subject of ...holding TRM conferences to discuss the condition and reach a consensus on treatment. A TRM conference has the significance of early intervention by the medical team and consensus on therapy from the medical doctors and family members. We report the case of scrub typhus infection with septic shock. On the day the patient was hospitalized, the medical team held a TRM conference and invited family members to attend. We found that the eschar on the patient may be related to scrub typhus, which was later confirmed by a positive Weil-Felix test and PCR analysis. Under the consensus treatment, the patient's condition improved considerably within the next day. The most significant difference between the TRM conference and the clinical specialist's consultation is that it can quickly narrow the cognitive gap between doctors and family members and reach a consensus on the patient's therapy strategy, truly avoid medical disputes, and effectively share the stress of attending physician. In this case report, we highlight the significance of the TRM conference.
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