Exploring the relationship between technology acceptance model and usability test

In the past, most studies used the technology acceptance model (TAM) to survey the subjective perception of users in using information technology. The usability test was also used to assess the ease of use of user interfaces. This study introduces a conceptual framework to explore the relationship between user’s beliefs of TAM and usability testing attributes. Usability testing was conducted on an eCampus learning system with a mobile device. TAM data was collected from the participants for analyzing a possible relationship. The findings of this study reveal that TAM results contradict the usability test results in certain areas. The focus of our proposed research model is supported from the causality between perceived ease of use and usability; however, the correlation between perceived usefulness and usability remains unclear.     

Fermentative bioenergy production from distillers grains using mixed microflora

The feasibility of hydrogen production from distillers grains substrate, an industrial cellulosic waste, was investigated. A substrate concentration of 80 g/L gave the maximum production at 50 °C and pH of 6.0 using sewage sludge. Four controllable factors with three levels: seed sludge (two sewage sludges and cow dung), temperature (40, 50, and 60 °C), pH (6, 7 and 8) and seed pretreatment (none, heat, and acid) were selected in Taguchi experimental design to optimize fermentation conditions. The peak hydrogen and ethanol productions were found with heat-treated cow dung seed, substrate concentration 80 g/L, 50 °C and pH 6. The peak hydrogen production rate and hydrogen yield were 7.9 mmol H₂/L/d and 0.40 mmol H₂/g-COD respectively whereas the peak ethanol production was 3050 mg COD/L and rate 0.22 g EtOH/L/d. A total bioenergy yield of 41 J/g substrate was obtained which was 21% and 79% from hydrogen and ethanol respectively.     

Fermentative biohydrogen production from starch-containing textile wastewater

The present study deals with the biohydrogen production from starch-containing wastewater collected from the textile industry in Taiwan. The effects of inoculums collected from different sources (sewage sludge, soil and cow dung), substrate concentrations (5–25 g COD/L) and pH (4.0–8.0) on hydrogen production from wastewater were investigated.     

Biohydrogen production from soluble condensed molasses fermentation using anaerobic fermentation

Using anaerobic micro-organisms to convert organic waste to produce hydrogen gas gives the benefits of energy recovery and environmental protection. The objective of this study was to develop a biohydrogen production technology from food wastewater focusing on hydrogen production efficiency and micro-flora community at different hydraulic retention times. Soluble condensed molasses fermentation (CMS) was used as the substrate because it is sacchariferous and ideal for hydrogen production. CMS contains nutrient components that are necessary for bacterial growth: microbial protein, amino acids, organic acids, vitamins and coenzymes. The seed sludge was obtained from the waste activated sludge from a municipal sewage treatment plant in Central Taiwan. This seed sludge was rich in Clostridium sp.A CSTR (continuously stirred tank reactor) lab-scale hydrogen fermentor (working volume, 4.0 L) was operated at a hydraulic retention time (HRT) of 3–24 h with an influent CMS concentration of 40 g COD/L. The results showed that the peak hydrogen production rate of 390 mmol H₂/L-d occurred at an organic loading rate (OLR) of 320 g COD/L-d at a HRT of 3 h. The peak hydrogen yield was obtained at an OLR of 80 g COD/L-d at a HRT of 12 h. At HRT 8 h, all hydrogenase mRNA detected were from Clostridium acetobutylicum-like and Clostridium pasteurianum-like hydrogen-producing bacteria by RT-PCR analysis. RNA based hydrogenase gene and 16S rRNA gene analysis suggests that Clostridium exists in the fermentative hydrogen-producing system and might be the dominant hydrogen-producing bacteria at tested HRTs (except 3 h). The hydrogen production feedstock from CMS is lower than that of sucrose and starch because CMS is a waste and has zero cost, requiring no added nutrients. Therefore, producing hydrogen from food wastewater is a more commercially feasible bioprocess.     

Economic potential of bioremediation using immobilized microalgae-based microbial fuel cells

Clean Technologies and Environmental Policy - The cathodic microalgae-based MFC converts the nutrients within wastewater and produces oxygen as oxygen supply for cathodic reactions, leading to the...     

Optimizing biohydrogen production from mushroom cultivation waste using anaerobic mixed cultures

The mushroom bag is a polypropylene bag stuffed with wood flour and bacterial nutrients. After being used for growing mushroom for one to two weeks this bag becomes mushroom cultivation waste (MCW). About 150 million bags (80,000 tons) of MCW are produced annually in Taiwan and are usually burned or discarded. The cellulosic materials and nutrients in MCW could be used as the feedstock and nutrients for anaerobic biohydrogen fermentation. This study aims to select the inoculum from various waste sludges (sewage sludge I, sewage sludge II, cow dung and pig slurry) with or without adding any extra nutrients. A batch test was operated at a MCW concentration of 20 g COD/L, temperature 55 °C and an initial cultivation pH of 8. The results show that extra nutrient addition inhibited hydrogen production rate (HPR) and hydrogen production yield (HY) when using cow dung and pig slurry seeds. However, nutrient addition enhanced the HPR and HY in case of using sewage sludge inoculum and without inoculum. This related to the inhibition caused by high nutrient concentration (such as nitrogen) in cow dung and pig slurry. Peak HY of 0.73 mmol H₂/g TVS was obtained with no inoculum and nutrient addition. However, peak HPR and specific hydrogen production rate (SHPR) of 10.11 mmol H₂/L/d and 2.02 mmol H₂/g VSS/d, respectively, were obtained by using cow dung inoculum without any extra nutrient addition.     

Thermophilic dark fermentation of untreated rice straw using mixed cultures for hydrogen production

Biohydrogen production from untreated rice straw using different heat-treated sludge, initial cultivation pH, substrate concentration and particle size was evaluated at 55 °C. The peak hydrogen production yield of 24.8 mL/g TS was obtained with rice straw concentration 90 g TS/L, particle size <0.297 mm and heat-treated sludge S1 at pH 6.5 and 55 °C in batch test. Hydrogen production using sludge S1 resulted from acetate-type fermentation and was pH dependent. The maximum hydrogen production (P), production rate (R_m) and lag (λ) were 733 mL, 18 mL/h and 45 h respectively. Repeated-batch operation showed decreasing trend in hydrogen production probably due to overloading of substrate and its non-utilization. PCR-DGGE showed both hydrolytic and fermentative bacteria (Clostridium pasteurianum, Clostridium stercorarium and Thermoanaerobacterium saccharolyticum) in the repeated-batch reactor, which perhaps in association led to the microbial hydrolysis and fermentation of raw rice straw avoiding the pretreatment step.     

Fermentative hydrogen production from wastewaters: A review and prognosis

Biohydrogen is a promising candidate which can replace a part of our fossil fuels need in day-to-day life due its perceived environmental benefits and availability through dark fermentation of organic substrates. Moreover, advances in biohydrogen production technologies based on organic wastewater conversion could solve the issues related to food security, climate change, energy security and clean development in the future. An evaluation of studies reported on biohydrogen production from different wastewaters will be of immense importance in economizing production technologies. Here we have reviewed biohydrogen production yields and rates from different wastewaters using sludges and microbial consortiums and evaluated the feasibility of biohydrogen production from unexplored wastewaters and development of integrated bioenergy process. Biohydrogen production has been observed in the range of substrate concentration 0.25–160 g COD/L, pH 4–8, temperature 23–60 °C, HRT 0.5–72 h with various types of reactor configuration. The most efficient hydrogen production has been obtained at an organic loading rate (OLR) 320 g COD/L/d, substrate concentration 40 g COD/L, HRT 3 h, pH 5.5–6.0, temperature 35 °C in a continuously-stirred tank reactor system using mixed cultures and fed with condensed molasses fermentation soluble wastewater. The net energy efficiency analysis showed vinasse wastewater has the highest positive net energy gain followed by glycerin wastewater and domestic sewage as 140.39, 68.65, 51.84 kJ/g COD feedstock with the hydrogen yield (HY) of 10 mmol/g COD respectively.