Electricity generation from disaccharides using microbial fuel cells

Bu çalışmada, lignoselülozik biyokütlelerin asit hidrolizatlarında yaygın olarak bulunan disakkaritlerden elektrik üretimi, tek odalı, hava-katot mikrobiyal yakıt hücreleri kullanılarak araştırılmıştır. Başlıca iki disakkariti (D-sellobiyoz, D-maltoz) kapsayan karbon kaynakları ile elektrik üretimi gözlenmiştir. Sodyum asetat ile zenginleştirilmiş karışık bakteri kültürü, test edilen bütün disakkaritlere kolayca adapte olmuştur. Yeni karbon kaynağına adaptasyon için gerekli süre de benzerlik gösterdi. Test edilen disakkaritler için elde edilen en yüksek güç yoğunluğu, 0.44-0.66 mA cm-2 direnç yoğunluğunda, sellobiyoz için 1262±5 mW m-2, maltoz içinse 1893±67 mW m-2 olarak bulunmuştur. Kolombik yeterlik sellobiyoz için yüzde 18, maltoz içinse yüzde 30 olarak bulunmuştur. Test edilen disakkaritler için, en yüksek volt eldesi ve substrat konsantrasyonu arasındaki ilişki 120 ohm dış dirençte doygunluk kinetiği sonuçları ile uyumluluk göstermiştir. Ön görülen en yüksek volt üretimi substratın çeşidine bağlı olarak, sellobiyoz için 0.34 V, yarı doygunluk kinetik sabiti, 626 mg L- (R2= 0.971), maltoz için ise 0.40 V ve yarı doygunluk kinetik sabiti 733 mg L-1 (R2= 0.998) olarak bulunmuştur. Test edilen disakkaritler için yüzde 81’nin üzerinde kimyasal oksijen talebinde azalma sağlanmıştır. Test edilen disakkaritlerin elektrik üretiminde karbon kaynağı olarak kullanılabileceği keşfedilmiştir. Çalışmamızın sonuçları, lignoselülozik maddelerden türevli disakkaritlerin ve lignoselüloz türevli maddelerin ön muamele ile mikrobiyal yakıt hücreleri için uygun birer karbon kaynağı olabileceklerini göstermiştir. Anahtar Kelimeler: Elektrik, disakkarit, mikrobiyal yakıt hücresi, performans.Researches on the finding renewable energy alternatives to fossil fuels have been great attention in recent years. The production of fuel and energy from lignocellulosic biomass such as agricultural residues and woody biomass has drawn significant attention because of the abundance, ready availability and renewable nature of these resources. The main components of lignocellulosic biomass are cellulose, hemicelluloses and lignin. Our previous study indeed demonstrated that all monosaccharides that can be directly generated from hydrolysis of lignocellulosic biomass were good sources for electricity generation in MFCs. However, lignocellulosic biomass cannot be directly utilized by microorganisms in MFCs for electricity generation.  In other words, lignocellulosic material has to be converted to sugars or other low-molecular-weight compounds.  The most commonly used method of converting lignocellulosic biomass to the sugars is through a dilute-acid pre-treatment and subsequent acid- or enzymatic hydrolysis processes. The dilute-acid pretreatment and the subsequent acid hydrolysis generate a number of byproducts, such as furan derivatives, phenolic compounds and carboxylic acids Our previous study shows that most of the phenolic compunds and furan derivatives do not have inhbitory effect on electricity generation. However, upto know, there is no information about the electricity generation in air-cathode single chamber mediator-less microbial fuel cells from tested disaccharides.  The acid hydrolysates from lignocellulosic materials such as pine wood or corn stover supposedly contain severall monosaccharides and disaccaharides previously described. Our preliminary results show that sulfuric acid hydrolysation (10%) of pine wood flour generate electricity in MFCs. However, it is poorly understood whether all the disaccharides can be utilized by bacteria in an MFC for electricity generation. Microbial fuel cell (MFC) technology uses microorganisms to catalyze the direct production of electricity from organic materials, and provides a new method for green energy generation from biomass. Various organic materials, such as glucose, xylose, acetate, butyrate, lactate, etc. as well as those from waste streams such as wastewaters can be used to generate direct electicity by MFCs. In this study, the direct production of electricity from disaccharides of lignocellulosic biomass was examined MFC performances by the disaccharides were evaluated as the following parameters: (1) Voltage generation, (2) power density generation, (3) Coulobic efficiency, (4) the removal of chemical oxygen demand and the effect of substrate concentration on electricity generation. Voltage was measured using a multimeter with a data acquisition system. Power density (mW m-2) was calculated according to P=IV/A, where I is the current, V voltage, and A the projected area of the anode. Electricity was produced from all disaccharides tested, including D-maltose and D-cellobiose. The mixed bacterial culture enriched using sodium acetate as a carbon source adapted well to all carbon sources tested. The adaptation time, which was defined as the time between adding a disaccharide solution to a MFC and reaching a maximum power output at 1000 W, was similar for each disaccharide. However, once the bacteria adapted to a new disaccharide, electricity was quickly recovered when the disaccharide solution was refilled. Maximum power density obtained from these disaccharides were 1262±5 mW m-2 for D-cellobiose, 1893±67 mW m-2 for D-maltose at current density of 0.44 and 0.66 mA cm-2, respectively. For two disaccharides tested, the maximum voltage output at 120  external resistance initially increased with the disaccharide concentration; however, further increases above a certain level did not improve the electricity generation Coulombic efficiency was 18% for D-cellobiose and 30% for D-maltose. For disaccharides tested, the relationship between the maximum voltage output and the substrate concentration appeared to follow saturation kinetics at 120  external resistance. The estimated maximum voltage output ranged between 0.34-0.40 V and half-saturation kinetic constants of 626 to 733 mg L-1for D-cellobiose and D-maltose, respectively. Chemical oxygen demand (COD) removal was over 81 % for disaccharides tested. Results from this study indicated that lignocellulosic biomass-derived disaccharides might be a suitable resource for electricity generation using MFC technology. Keywords: Electricity, microbial fuel cell, disaccharide, performance

Investigation of bamboo pulp fiber-reinforced unsaturated polyester composites

Mechanical pulp fibers (MPFs) and chemical pulp fibers (CPFs) from moso bamboo have been characterized in terms of their length and width distributions, and their reinforcing effects in unsaturated polyester (UPE) composites have also been investigated. CPF-UPE composites had much higher tensile strength, flexural strength, and flexural modulus than MPF-UPE composites. CPF-UPE composites also absorbed less water than MPF-UPE composites. Treatments of the fibers with a combination of 1,6-diisocyanatohexane (DIH) and 2-hydroxyethyl acrylate (HEA) significantly increased the tensile strength, flexural strength, flexural modulus, and water resistance of the resulting composites. Fourier transform infrared and X-ray photoelectron spectroscopy analyses indicated that DIH-HEA was bound onto bamboo fibers (BFs) via carbamate linkages. The scanning electron microscopy images of the tensile-fractured surfaces of the composites revealed that the DIH-HEA treatments for BFs greatly improved the interfacial adhesion between the fibers and UPE resins.Keywords: water resistance, unsaturated polyester, mechanical properties, surface treatments, bamboo fibers, interfacial adhesionKeywords: water resistance, unsaturated polyester, mechanical properties, surface treatments, bamboo fibers, interfacial adhesio

Chronology of the Basalt Units Surrounding Chang’e-4 Landing Area

The Chang’e-4 (CE-4) lunar probe, the first soft landing spacecraft on the far side of the Moon, successfully landed in the Von Kármán crater on 3 January 2019. Geological studies of the landing area have been conducted and more intensive studies will be carried out with the in situ measured data. The chronological study of the maria basalt surrounding the CE-4 landing area is significant to the related studies. Currently, the crater size-frequency distribution (CSFD) technique is the most popular method to derive absolute model ages (AMAs) of geological units where no returned sample is available, and it has been widely used in dating maria basalt on the lunar surface. In this research, we first make a mosaic with multi-orbital Chang’e-2 (CE-2) images as a base map. Coupled with the elevation data and FeO content, nine representative areas of basalt units surrounding the CE-4 landing area are outlined and their AMAs are derived. The dating results of the nine basalt units indicate that the basalts erupted from 3.42 to 2.28 Ga ago in this area, a period much longer than derived by previous studies. The derived chronology of the above basalt units establishes a foundation for geological analysis of the returned CE-4 data

Aboveground dry matter and grain yield of summer maize under different varieties and densities in North China Plain

To increase summer maize grain yield in North China Plain, we conducted field experiments with three densities (3, 6, and 9 plants m-2) on two plant types (a flat type, LD981, and a compact type, LD818) during 2010 and 2011 summer maize growing seasons to study leaf area index (LAI), above ground dry matter accumulation, grain filling rate, and grain yield. The results indicated that with the density increased, the LAI in the both varieties enhanced; however, plant density at the rate of 9 plants m-2 significantly (LSD, P < 0.05) increased LAI in LD818. Increasing densities enhanced the above ground dry matter of LD818, but not of LD981. With the density increased, the grain filling rate in the both varieties declined, but during the later growing season, the grain filling rate in LD818 was higher than that in LD919. Irrespective of plant density at the rate of from 3 to 6 or 6 to 9 plants m-2, the grain No. per ear, 1,000-kernel weight, and ears No. per m2 in LD981 were all lower than those in LD818; this was the main reason why with the increased density, the population yield in LD981 was lower than that in LD818. These results indicate that in North China Plain, increasing plant density could enhance the grain yield of compact type summer maize

A reanalysis of the relationship between the size of boulders and craters in lunar surface

To distinguish secondary craters from primary craters is very important in lunar studies that involve such tasks as dating the lunar surface and investigating the meteoritic flux. However, this is usually difficult since distant secondary craters generally have an appearance similar to primary ones. Bart and Melosh (2007a, 2007b) proposed a method to distinguish the two types of craters based on the relationship between the crater diameter (D) and the size of the largest boulder (B) around the crater: B =KD2/3, where K is the fitting coefficient. They concluded that secondary craters have a 60% larger fitting coefficient (K) than primary craters. However, because of the poor quality of the available data and an insufficient number of crater samples, their results need further substantiation, as they have suggested. This research aims to examine their results with recently obtained very high resolution data and many more sampled craters. Our results indicate that the criterion proposed by Bart and Melosh (2007a, 2007b) is actually not applicable, i.e., the fitted coefficient (K), in cases of primary and secondary craters, cannot be confidently distinguished

A Generative Adversarial Network for Pixel-Scale Lunar DEM Generation from High-Resolution Monocular Imagery and Low-Resolution DEM

Digital elevation models (DEMs) provide fundamental data for scientific and engineering applications in lunar exploration missions. Lunar DEMs have been mainly generated by laser altimetry and stereophotogrammetry. Complementarity to stereo photogrammetry, reflection-based surface reconstruction methods, such as shape from shading (SFS), have been studied and applied in lunar DEM reconstruction from a single image. However, this method often suffers from solution ambiguity and instability. In this paper, we propose a generative adversarial network (GAN)-based method that is able to generate high-resolution pixel-scale DEMs from a single image aided by a low-resolution DEM. We have evaluated the accuracy of the reconstructed high-resolution DEMs from 25 LROC NAC images of four regions using LROC NAC DEMs (2 m/pixel) as ground truth. The experimental results demonstrate good accuracy and adaptability to changes in illumination conditions. The root mean square error (RMSE) can reach about 2 m in areas where the degree of elevation variation is less than 100 m, and the RMSE value ranges from around 3 m to 10 m without considering the degree of the elevation variation in large-area reconstruction. As high-resolution monocular images and low-resolution DEMs are available for the entire lunar surface, the proposed GAN-based method has great potential in high-resolution lunar DEM reconstruction for lunar mapping applications

A Generative Adversarial Network for Pixel-Scale Lunar DEM Generation from High-Resolution Monocular Imagery and Low-Resolution DEM

Digital elevation models (DEMs) provide fundamental data for scientific and engineering applications in lunar exploration missions. Lunar DEMs have been mainly generated by laser altimetry and stereophotogrammetry. Complementarity to stereo photogrammetry, reflection-based surface reconstruction methods, such as shape from shading (SFS), have been studied and applied in lunar DEM reconstruction from a single image. However, this method often suffers from solution ambiguity and instability. In this paper, we propose a generative adversarial network (GAN)-based method that is able to generate high-resolution pixel-scale DEMs from a single image aided by a low-resolution DEM. We have evaluated the accuracy of the reconstructed high-resolution DEMs from 25 LROC NAC images of four regions using LROC NAC DEMs (2 m/pixel) as ground truth. The experimental results demonstrate good accuracy and adaptability to changes in illumination conditions. The root mean square error (RMSE) can reach about 2 m in areas where the degree of elevation variation is less than 100 m, and the RMSE value ranges from around 3 m to 10 m without considering the degree of the elevation variation in large-area reconstruction. As high-resolution monocular images and low-resolution DEMs are available for the entire lunar surface, the proposed GAN-based method has great potential in high-resolution lunar DEM reconstruction for lunar mapping applications

New Lunar Crater Production Function Based on High-Resolution Images

The lunar crater production function describes the general pattern of the size–frequency distribution of craters on the lunar surface, and it is the foundation of the surface dating method via crater counting. In addition, the lunar crater production function has been extended to other celestial bodies and used to analyze the meteorite flux of the inner solar system. The basic process of establishing the lunar crater production function is to map in an ideal way the primary craters in different geological units, and then to normalize all of the corresponding size–frequency distributions using a mathematical model. Currently, the most widely used lunar crater production functions have been established based on the images acquired in the last century. However, now they can be refined with newly obtained high-resolution images. In this research, we mapped all of the primary craters in 13 regions on the lunar surface with the images acquired using the narrow angle camera and wide angle camera onboard the Lunar Reconnaissance Orbiter, and then we fitted the lunar crater production function with a polynomial. The resultant new lunar crater production function is largely comparable with the previous results, and the difference is mainly at the large diameter end. We analyzed the uncertainty of model fitting as well as the difference in the crater measurements and demonstrated the reliability of the new production function. It is expected to refine the lunar surface dating models, which can provide more accurate information on the impact rate in related studies

Characterization Assessment of Cotton Fabric Dyed by Dioscorea cirrhosa Dry Extract

Dioscorea cirrhosa is a natural plant with advantageous properties in both health care and dyeing. In this work, cotton fabric was dyed with Dioscorea cirrhosa dry extract by the traditional, repeated, dip-spray dyeing process and single-side sunlight fixation method. The color characteristics, surface morphology and structure, chemical composition, and mechanical properties of the dyed cotton fabric were characterized. The flame-retardant and waterproof functions of the dyed cotton fabric were also evaluated. The results showed that the dyed cotton fabric presented the limiting oxygen index (LOI) with one side displaying a reddish-brown coating and the other side being red. The limiting oxygen index of the cotton fabric increased from 18% to 28% after dyeing treatment

Synthesis, mechanical and electrical properties of carbon microcoils and nanocoils\ud

The results on the synthesis, mechanical and electrical properties of carbon microcoils and nanocoils (CMCs, CNCs) synthesized using catalytic CVD and Ni-P and Co-P catalyst alloys, respectively, are reported. SEM analysis reveals that the CMCs and CNCs have unique helical morphologies, and diameters of 5.0-9.0 μm and 450-550 nm, respectively. Moreover, CMCs with flat cross-section can be stretched to 3 times their original coil lengths. Current-voltage characteristics of a single microcoil have also been obtained. It is found that the CMCs have the electrical conductivity between 100 and 160 S/cm, whereas the electrical resistance increases by about 20% during the coil extension. Besides, the microcoils can produce light in vacuum when the test voltage reaches 10 V. The emission intensity increases as the voltage increases. The mechanical and electrical properties of CMCs and CNC make them potentially useful in many applications in micromagnetic sensors, mechanical microsprings and optoelectronics