Inside and Outside Flank Alternate Meshing Silent Chain and Experimental Evaluation of Dynamic Performance

Abstract: A new silent chain with inside and outside flank alternating meshing mechanism and sprockets were designed, and the main technical parameters and structure type of the plate and sprocket profile were described. In order to verify the good meshing transmission performance of the new silent chain, we did the performance comparison test for inside and outside flank alternate meshing silent chain and the ANSI standard silent chain with regard to transverse displacement vibration and wear extension. The results show that the new silent chain transmits smoothly, with standard silent chain compared to significantly reduce vibration quantity of transverse displacement, and it has good wear resistance properties, which is much superior to the standard silent chain. The results also verify low impact characteristics of the new silent chain and the rationality of design method. Because of its special meshing mechanism and structure type of alternate load, the new silent chain reduces meshing impact, vibration and polygon effect when chain and sprocket meshes, and fundamentally improves silent chain transmission performance, then extends the life of the chain

Synthesis and Biological Activity of Organothiophosphoryl Polyoxotungstates

Organothiophosphoryl polyoxotungstates R∋XW∞∞O∋∃/- , R∋ P∋W∞,O∞/-, R∋PW∃O∋ Δ-(X = P, Si, Ge, B or Ga; R = PhP(S), C6H11P(S)) have been prepared from lacunary polyoxoanions and PhP(S). The products were characterized by elemental analysis, IR, and NMR spectroscopy. According to spectroscopic observations, the hybrid anions consist of a lacunary anion framework on which are grafted two equivalent or groups through P-O-W bridges. Some of the title compounds showed the antigerm activity

A note on the total chromatic number of Halin graphs with maximum degree 4

AbstractIn this paper, we prove that χT(G) = 5 for any Halin graph G with Δ(G) = 4, where Δ(G) and χT(G) denote the maximal degree and the total chromatic number of G, respectively

COMPARATIVE HISTOLOGICAL ANALYSIS OF INTESTINES OF LOACH, GRASS CARP AND CATFISH PROVIDE INSIGHTS INTO ADAPTIVE CHARACTERISTICS IN AIR-BREATHING FISH

Općenito je prihvaćeno da su pomoćni dišni organi riba u više navrata samostalno evoluirali pri prilagođavanju slatkovodnim staništima i vodenoj hipoksiji. Vjeruje se da je organ za udisanje zraka kod riba strukturno modificiran kako bi nadopunio respiraciju. U ovom istraživanju prezentirani su intuitivni dokazi detaljne strukturne modifikacije crijeva i organa za udisanje zraka kod muljnog vijuna (Misgurnus anguillicaudatus), uspoređujući ih amurom (Ctenopharyngodon idellus) i žutim somom (Pelteobagrus fulvidraco). izravno dobiveni histološkom i morfometrijskom metodom. Kod muljnog vijuna očitovala se naglo smanjena visina nabora sluznice i debljina mišićnog sloja od prednjeg do stražnjeg dijela crijeva. U usporedbi sa amurom i žutim somom, vijun je imao i najmanji omjer visine nabora sluznice/debljine mišićnog sloja i polumjera crijeva u stražnjem dijelu crijevu. To sugerira da je moguće stražnji dio crijeva lokacija na kojoj vijun udiše zrak. Nadalje, gustoća kapilara (0,46 ± 0,05 μm-2) u zadnjem crijevu vijuna bila je značajno viša od amura i žutog soma. Također, difuzijska udaljenost zračno-krvne barijere (1,34 ± 0,04 μm) u stražnjem crijevu vijuna bila je značajno manja od one u druge dvije vrste riba. Ukratko, karakteristike poput visoke prokrvljenosti, kratke udaljenosti difuzije zračno-krvne barijere, prorijeđenosti i spljoštenosti, učinile su stražnji dio crijeva savršenom lokacijom za udisanje zraka istraživane vrste vijuna.Accessory respiratory is generally accepted to have evolved independently on numerous occasions in adaption to aquatic hypoxia in freshwater habitats. In general, the air-breathing organ in fish is believed to be structurally modified to supplement respiration. In this study, intuitive evidence for elaborate structural modifications of the intestine, an air-breathing organ in mud loach (Misgurnus anguillicaudatus), compared with two other obligate aquatic breathers, grass carp (Ctenopharyngodon idellus) and yellow catfish (Pelteobagrus fulvidraco), were directly provided by histological and morphometric methods. As a result, a sharply decreasing height of mucosal folds and thickness of muscularis were manifested in loach intestine from its anterior to posterior region. Compared with grass carp and yellow catfish, loach had the smallest ratios of mucosal fold height/muscularis thickness to intestinal lumen radius in the posterior intestine. These suggested that the posterior intestine is the air-breathing location for the loach. Furthermore, length density of capillary (0.46±0.05 μm-2) in the posterior intestine of the loach was significantly higher than those of grass carp and yellow catfish. Meanwhile, diffusion distance of air-blood barrier (1.34±0.04 μm) in the posterior intestine of the loach was significantly smaller than those of the other two fish species. In summary, the characteristics of highly vascularized, short diffusion distance of air-blood barrier, thinned and flattened made the posterior intestine a perfect air-breathing location for the loach

Robust Coordinated Control Algorithm for Multiple Marine Vessels with External Disturbances

The problem of coordinated control for multiple marine vessels in the presence of external disturbances is considered in this paper. A robust coordinated control algorithm is proposed for multiple marine vessels. The proposed robust coordinated control algorithm is divided into two parts. The first part develops an extended state observer to estimate the disturbances of marine vessels. The second part presents a robust coordinated control algorithm based on the output of the extended state observer. Furthermore, the robust coordinated control algorithm is designed using the dynamic surface control method. In light of the leader-follower strategy, the trajectory for each vessel is defined according to the desired trajectory of the assigned leader and the relative distance with respect to the leader. The effectiveness of the proposed coordination algorithm is demonstrated by the simulation results

Carbapenem-Resistant Klebsiella pneumoniae Infection in Three New York City Hospitals Trended Downwards From 2006 to 2014

Background. Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a rising public health threat since its first outbreaks in New York City (NYC) in the early 2000s. We investigated annual trends of CRKP infection in hospital-acquired infections (HAIs) and community-onset infections (COIs) treated in 3 NYC hospitals from 2006 to 2014. Methods. We extracted K pneumoniae infection data including carbapenem susceptibility and anatomical sites, compared clinical characteristics between CRKP and carbapenem-susceptible K pneumoniae infections, and determined CRKP infection proportions in total K pneumoniae infections in HAI and COI to identify statistically significant trends from 2006 to 2014 using the Cochran-Armitage trend test. Results. Carbapenem-resistant K pneumoniae contributed 17.3% (601 of 3477) of hospital-acquired K pneumoniae infection compared with 7.7% (149 of 1926) in COI from 2006 to 2014. Carbapenem-resistant K pneumoniae proportions in HAI and COI were positively correlated over time (r = 0.83, P < .01), and there were downward annual trends of CRKP proportions from 2006 to 2014 in both HAI and COI (25.8% to 10.5% in HAI, P < .001; 13.6% to 3.1% in COI, P < .001). By anatomical site, significant downward annual trends were present only in urinary tract infection (P < .001 for both HAI and COI) from 2006 to 2014. Conclusions. Annual trends of CRKP proportions from 2006 to 2014 were downward in both HAI and COI, and HAI and COI were positively correlated. Efforts to reduce and prevent CRKP infections in both hospital and community settings were successful and warrant continuation

Tetra­kis(μ3-2-{[1,1-bis­(hydroxy­meth­yl)-2-oxidoeth­yl]imino­meth­yl}-6-methoxy­phenol­ato)tetra­nickel(II) tetra­hydrate

The title complex, [Ni4(C12H15NO4)4]·4H2O, has crystal­lographic fourfold inversion symmetry, with each NiII ion coordinated in a slightly distorted square-pyramidal coordination environment and forming an Ni4O4 cubane-like core. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds connect complex and water mol­ecules to form a three-dimensional network. The O atom of one of the unique hydroxy­methyl groups is disordered over two sites, with the ratio of occupancies being approximately 0.79:0.21

Organic geochemistry evidence for wildfire and elevated pO2 at the Frasnian–Famennian boundary

The Devonian experienced radiations of plants and animals, as well as a major mass extinction event during the Frasnian–Famennian (Fsingle bondF) interval. Proposed triggers have been linked to volcanism, extraterrestrial impact, sea-level fluctuations, and climate cooling, etc. However, the nature of the wildfires and its role in the biotic evolution have been rarely investigated for the Fsingle bondF interval. Here, we report organic geochemistry proxies (e.g., polycyclic aromatic hydrocarbons, PAHs) in three sections from New York (USA) to further investigate the wildfire activity and its potential link with the environmental and biotic perturbations around the Fsingle bondF interval. The studied intervals are dominated by three-ring PAHs which display an increasing abundance stratigraphically towards the Fsingle bondF boundary (FFB). An increase of 6-ring over 3-ring PAHs across the FFB is also observed for the studied sections, indicating elevated burning temperature. Additionally, slightly increased plant wax abundance and average chain length values and relatively constant Pr/Ph ratios are observed. Collectively, these results propose an increased burning frequency over the Fsingle bondF interval caused by elevated pO2 level, rather than a change in aridity. Terrestrial input only slightly increased across the FFB, and there is limited evidence for ocean anoxia. This correlates with the hypothesis that pCO2 drawdown and climate cooling could have been a driving mechanism of the Fsingle bondF biocrisis