Hydrogen production by mixed culture of several facultative bacteria and anaerobic bacteria

AbstractThe characteristic of hydrogen production by facultative anaerobic bacteria, obligate anaerobic bacteria and their mixed culture was studied by the batch culture method. The results showed that, due to the synergistic effect between facultative bacteria and anaerobic bacteria, the ability of hydrogen production in the mixed culture was much better than that in the pure culture. Especially, the culture Scheme No.7 mixed up with three strains (Bacterium. E: Bacterium. B: Bacterium. P = 1:1:1) not only had the best hydrogen production capacity (1.885 mol H2/mol glucose) and maximum average hydrogen production rate (212.2 mL/(L·h)), but also had stable hydrogen production under continuous culture conditions, which was 1.968 mol H2/mol glucose

Half Metallic Bilayer Graphene

Charge neutral bilayer graphene has a gapped ground state as transport experiments demonstrate. One of the plausible such ground states is layered antiferromagnetic spin density wave (LAF) state, where the spins in top and bottom layers have same magnitude with opposite directions. We propose that lightly charged bilayer graphene in an electric field perpendicular to the graphene plane may be a half metal as a consequence of the inversion and particle-hole symmetry broken in the LAF state. We show this explicitly by using a mean field theory on a 2-layer Hubbard model for the bilayer graphene.Comment: 4+ pages, 4 figure

A Method against Interrupted-Sampling Repeater Jamming Based on Energy Function Detection and Band-Pass Filtering

Interrupted-sampling repeater jamming (ISRJ) is a new kind of coherent jamming to the large time-bandwidth linear frequency modulation (LFM) signal. Many jamming modes, such as lifelike multiple false targets and dense false targets, can be made through setting up different parameters. According to the “storage-repeater-storage-repeater” characteristics of the ISRJ and the differences in the time-frequency-energy domain between the ISRJ signal and the target echo signal, one new method based on the energy function detection and band-pass filtering is proposed to suppress the ISRJ. The methods mainly consist of two parts: extracting the signal segments without ISRJ and constructing band-pass filtering function with low sidelobe. The simulation results show that the method is effective in the ISRJ with different parameters

Kinetic Modeling for Microwave-Enhanced Degradation of Methylene Blue Using Manganese Oxide

This study was originally performed to compare the MnO2-based degradation of aqueous methylene blue (MB) under microwave irradiation- (MW-) enhanced and conventional heating- (CH-) enhanced conditions. The degradation process and kinetics were investigated to elucidate the microwave effect on the reaction. The results showed that all three tested conditions, sole MnO2, MnO2/CH, and MnO2/MW, followed the third-order (second upon MB and first upon MnO2) kinetic model. However, a higher degradation rate of MB was available under the MW-enhanced process, which implies that the “athermal effect” of MW might be of more benefit for the generation of electrophilic oxygen ions (, , and ) to degrade MB. The results showed that the degradation percentage of MB could reach 100%, corresponding to 92% total organic carbon (TOC) removal under microwave irradiation at pH 7.20 for 10 min

Link-based quantitative methods to identify differentially coexpressed genes and gene Pairs

<p>Abstract</p> <p>Background</p> <p>Differential coexpression analysis (DCEA) is increasingly used for investigating the global transcriptional mechanisms underlying phenotypic changes. Current DCEA methods mostly adopt a gene connectivity-based strategy to estimate differential coexpression, which is characterized by comparing the numbers of gene neighbors in different coexpression networks. Although it simplifies the calculation, this strategy mixes up the identities of different coexpression neighbors of a gene, and fails to differentiate significant differential coexpression changes from those trivial ones. Especially, the correlation-reversal is easily missed although it probably indicates remarkable biological significance.</p> <p>Results</p> <p>We developed two link-based quantitative methods, DCp and DCe, to identify differentially coexpressed genes and gene pairs (links). Bearing the uniqueness of exploiting the quantitative coexpression change of each gene pair in the coexpression networks, both methods proved to be superior to currently popular methods in simulation studies. Re-mining of a publicly available type 2 diabetes (T2D) expression dataset from the perspective of differential coexpression analysis led to additional discoveries than those from differential expression analysis.</p> <p>Conclusions</p> <p>This work pointed out the critical weakness of current popular DCEA methods, and proposed two link-based DCEA algorithms that will make contribution to the development of DCEA and help extend it to a broader spectrum.</p

Hydraulic fracturing propagation mechanism during shale gas reservoir stimulation through horizontal well

Način razlamanja stijenske mase u naslagama naftnih škriljaca jedan je od glavnih čimbenika koji djeluju na učinkovitost hidrauličkog frakturiranja (frakiranja). U ovom su radu provedena fizikalna ispitivanja i numeričko modeliranje u svrhu sustavnog ispitivanja učinka in-situ (podzemnog) naprezanja i kuta bušenja na stvaranje tlaka zbog hidrauličkog frakturiranja, širenje razlamanja i način razlamanja u horizontalnoj bušotini naftnog nalazišta Shengli u Luojia pokrajini, u izvođenju Sinopec Corp. Ukupno je razmatrano šest različitih in-situ kombinacija naprezanja i osam različitih kutova bušenja slojevite stijenske mase tijekom hidrauličkog frakturiranja. Sažetak nastanka i širenja pukotine te završni oblici pukotina nastalih hidrauličkim frakturiranjem u slojevitim stijenskim masama otkrivaju da kod stratificiranih stijena s istim kutom bušenja, što je veći in-situ omjer naprezanja (t.j. niže maksimalno horizontalno osnovno naprezanje pri konstantnim vertikalnim naprezanjem), potreban je niži hidraulički tlak za poticanje i širenje hidrauličkog frakturiranja. Štoviše, ustanovljeno je da je kod stratificirane stijenske mase pri istom omjeru naprezanja, tlak hidrauličkog frakturiranja, u slučaju kad je kut bušenja 30°, veći nego u svim drugim slučajevima. Nadalje, zapaženo je da učinak stratifikacije na hidrauličko frakturiranje postaje slabiji s porastom in-situ omjera naprezanja. Konačno je zaključeno da rezultati ove analize mogu biti važan teorijski pokazatelj u poboljšanju oblikovanja hidrauličkog frakturiranja kako bi se osiguralo učinkovito stimuliranje naslaga naftnih škriljaca.The fracture pattern of rock mass in shale gas reservoirs is one of the main factors affecting the efficiency of hydraulic fracturing. In this paper, physical experiments and numerical modelling were conducted to systematically investigate the effect of the in-situ stress and perforation angle on the hydraulic fracture initiation pressure and location, fracture propagation, and fracture pattern in a horizontal well drilled by Sinopec Corp. in Luojia area of Shengli Oilfield. A total of six different in-situ stress combinations and eight different perforation angles were considered for the stratified rock mass during the hydraulic fracturing. A summary of the fracture initiations and propagation, and the final fracture patterns induced by the hydraulic fracturing in the stratified rock masses reveals that, for the stratified rock masses with the same perforation angle, the larger the in-situ stress ratio (i.e. lower maximum horizontal principal stress when the vertical stress remains constant) is, the lower hydraulic pressure is required for hydraulic fracturing initiation and propagation. Moreover, it is found that, for the stratified rock mass under the same stress ratio, the hydraulic fracturing pressure in the case with a perforation angle of 30° is higher than that in all other cases. Furthermore, it is noted that the effect of the stratification on the hydraulic fracturing becomes weaker with the in-situ stress ratio increasing. It is finally concluded that the results from this study can provide important theoretical guidance for improving the hydraulic fracturing design in order to ensure the effective shale gas reservoir stimulations

Dichlorido(2,9-dimeth­oxy-1,10-phenanthroline-κ2 N,N′)zinc(II)

In the crystal structure of the title compound, [ZnCl2(C14H12N2O2)], the ZnII center is four-coordinated by two N atoms from one 2,9-dimeth­oxy-1,10-phenanthroline ligand and two Cl atoms. The coordination geometry is distorted tetra­hedral, as the Zn—N bond distances are shorter than the Zn—Cl distances, and the Cl—Zn—N and Cl—Zn—Cl bond angles are much larger than the N—Zn—N angle. For the ligand, the O and C atoms of the meth­oxy groups are almost in the plane defined by the phenanthroline ring. The two O atoms deviate from the phenanthroline mean plane by 0.076 (2) and 0.084 (2) Å, and the two methyl C atoms deviate from the phenanthroline mean plane by 0.035 (3) and 0.361 (3) Å. There are medium π–π stacking interactions between two parallel phenanthroline rings with a centroid–centroid distance of 3.7860 (2) Å and a dihedral angle between the plane defined by the two parallel phenanthroline rings of 1.13 (5)°