Study on High-Strength Ring Chain Dynamic Characteristics under Different Launch Parameters

The aim of this study is to investigate the mechanical characteristics of the high-strength ring chain under various launch parameters and the energy consumption caused by this. Particularly, the contact dynamics simulation was implemented in ABAQUS to study the launch characteristics impacted by different chain speeds different transportation loads, and the results were proved by experiments. The results show that stable stresses under different launch speeds are diverse, and the launch speed which makes the performance best is 5.6 m/min; stable stresses under different loads are diverse, and in the overload-launch process, the normal force of the chain increases multi-fold so that the chain will be great damaged; The energy consumption caused by the friction among high-strength ring chains under no-load operation occupies 23.8% of the resistance consumption. With the rise in loads, the total resistance consumption grow linearly. As a consequence, the research has great significance for the research of ring chain launch characteristics, the forecast of the chain's operating life and the efficiency improvement of electromotors.Исследованы механические характеристики высокопрочной кольцевой цепи транспортного оборудования при различных рабочих параметрах и связанное с этим энергопотребление. Динамическая контактная задача моделируется с помощью конечноэлементного пакета ABAQUS для различных транспортных нагрузок и скоростей движения цепи с последующей экспериментальной верификацией полученных результатов. Установлено, что оптимальное функционирование цепи соответствует скорости движения 5,65 м/мин, при которой деформация и напряжение являются стабильными. В режиме перегрузки нормальное напряжение возрастает многократно, что приводит к существенному повреждению цепи. Показано, что при холостом режиме работы цепи 23,8% потребляемой энергии расходуется на преодоление сил трения. При увеличении рабочей нагрузки наблюдается линейный рост потребляемой энергии. Полученные динамические механические характеристики цепи позволяют уточнить прогноз ее долговечности в условиях эксплуатации и усовершенствовать схему энергопитания электромоторов.Досліджено механічні характеристики високоміцного кільцевого ланцюга транспортного обладнання за різних робочих параметрів та зв язане з цим енергоспоживання. Динамічна контактна задача моделюється за допомогою скінченноелементного пакета ABAQUS для різних транспортних навантажень і швидкостей руху ланцюга з подальшою експериментальною верифікацією отриманих результатів. Установлено, що оптимальне функціонування ланцюга відповідає швидкості руху 5,65 м/хв., за якої деформація і напруга є стабільними. У режимі перевантаження нормальна напруга збільшується багаторазово, що призводить до суттєвого пошкодження ланцюга. Показано, що при холостому режимі роботи ланцюга 23,8% споживаної енергії витрачається на подолання сил тертя. Із підвищенням робочого навантаження відмічається лінійне зростання споживаної енергії. Отримані динамічні механічні характеристики ланцюга дозволяють уточнити прогноз його довговічності в умовах експлуатації та удосконалити схему енергоспоживання електромоторів

Telehealthcare for asthma

BACKGROUND: Healthcare systems internationally need to consider new models of care to cater for the increasing numbers of people with asthma. Telehealthcare interventions are increasingly being seen by policymakers as a potential means of delivering asthma care. We defined telehealthcare as being healthcare delivered from a distance, facilitated electronically and involving the exchange of information through the personalised interaction between a healthcare professional using their skills and judgement and the patient providing information. OBJECTIVES: To assess the effectiveness of telehealthcare interventions in people with asthma. SEARCH METHODS: We searched in the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED, and PsycINFO; this was supplemented by handsearching of respiratory journals. We also searched registers of ongoing and unpublished trials. SELECTION CRITERIA: We selected completed randomised controlled trials of telehealthcare initiatives aiming to improve asthma care. DATA COLLECTION AND ANALYSIS: Two review authors independently appraised studies for inclusion and extracted data and performed meta‐analyses. We analysed dichotomous variables to produce an odds ratio (OR) and continuous variables to produce a mean difference. MAIN RESULTS: We included 21 trials in this review. The 21 included studies investigated a range of technologies aiming to support the provision of care from a distance. These included: telephone (n = 9); video‐conferencing (n = 2); Internet (n = 2); other networked communications (n = 6); text Short Messaging Service (n = 1); or a combination of text and Internet (n = 1). Meta‐analysis showed that these interventions did not result in clinically important improvements in asthma quality of life (minimum clinically important difference = 0.5): mean difference in Juniper's Asthma Quality of Life Questionnaire (AQLQ) 0.08 (95% CI 0.01 to 0.16). Telehealthcare for asthma resulted in a non‐significant increase in the odds of emergency department visits over a 12‐month period: OR 1.16 (95% CI 0.52 to 2.58). There was, however, a significant reduction in hospitalisations over a 12‐month period: OR 0.21 (95% CI 0.07 to 0.61), the effect being most marked in people with more severe asthma managed predominantly in secondary care settings. AUTHORS' CONCLUSIONS: Telehealthcare interventions are unlikely to result in clinically relevant improvements in health outcomes in those with relatively mild asthma, but they may have a role in those with more severe disease who are at high risk of hospital admission. Further trials evaluating the effectiveness and cost‐effectiveness of a range of telehealthcare interventions are needed

Long-term measurements of particle number size distributions and the relationships with air mass history and source apportionment in the summer of Beijing

A series of long-term and temporary measurements were conducted to study the improvement of air quality in Beijing during the Olympic Games period (8–24 August 2008). To evaluate actions taken to improve the air quality, comparisons of particle number and volume size distributions of August 2008 and 2004–2007 were performed. The total particle number and volume concentrations were 14 000 cm−3 and 37 μm−3 cm−3 in August of 2008, respectively. These were reductions of 41% and 35% compared with mean values of August 2004–2007. A cluster analysis on air mass history and source apportionment were performed, exploring reasons for the reduction of particle concentrations. Back trajectories were classified into five major clusters. Air masses from the south direction are always associated with pollution events during the summertime in Beijing. In August 2008, the frequency of air mass arriving from the south was 1.3 times higher compared to the average of the previous years, which however did not result in elevated particle volume concentrations in Beijing. Therefore, the reduced particle number and volume concentrations during the 2008 Beijing Olympic Games cannot be only explained by meteorological conditions. Four factors were found influencing particle concentrations using a positive matrix factorization (PMF) model. They were identified as local and remote traffic emissions, combustion sources as well as secondary transformation. The reductions of the four sources were calculated to 47%, 44%, 43% and 30%, respectively. The significant reductions of particle number and volume concentrations may attribute to actions taken, focusing on primary emissions, especially related to the traffic and combustion sources

Persistence Probabilities of the German DAX and Shanghai Index

We present a relatively detailed analysis of the persistence probability distributions in financial dynamics. Compared with the auto-correlation function, the persistence probability distributions describe dynamic correlations non-local in time. Universal and non-universal behaviors of the German DAX and Shanghai Index are analyzed, and numerical simulations of some microscopic models are also performed. Around the fixed point $z_0=0$, the interacting herding model produces the scaling behavior of the real markets

Determination of folic acid and its related substances of the ferrous fumarate and folic acid dispersible tablet by HPLC

The aim of the present study was to establish a method for the determination of folic acid and related substances content in dispersible tablets. Method: A Shim-pack VP-ODS C18 reversed phase column (4.6 mm × 250 mm) was used. The mobile phase consisted of methanol-phosphate buffer (20:80) with a pH of 6.3.The flow rate was 1.0 mL/min, and the detection wavelength was 277nm and the column temperature was 30 °C. Results: The calibration curve was linear in the range of 5~150 μg/mL (r = 0.9998) for folic acid. The minimal detection limit was 99.08 %, n = 9 and the related substances were well separated. This method resulted to be convenient, accurate, selective and reliable, and can be applied for the quality control of folic acid.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Impacts of the East Asian monsoon on lower tropospheric ozone over coastal South China

The impact of the East Asian monsoon (EAM) on climatology and interannual variability of tropospheric ozone (O3) over the coastal South China was investigated by analyzing 11 years of ozonesonde data over Hong Kong with the aid of Lagrangian dispersion modeling of carbon monoxide and calculation of an EAM index. It was found that the seasonal cycle of O3 in the lower troposphere is highly related to the EAM over the study region. Ozone enhancements in the free troposphere are associated with the monsoon-induced transport of pollutants of continental anthropogenic and biomass burning origins. Lower tropospheric O3 levels showed high interannual variability, with an annual averaged amplitude up to 61% of averaged concentrations in the boundary layer (0–1 km altitudes) and 49% below 3 km altitude. In spring and autumn, the interannual variability in boundary layer O3 levels was predominately influenced by the EAM intensity, with high O3 mixing ratios associated with northeasterly circulation anomalies

A Naturally Narrow Positive Parity Theta^+

We present a consistent color-flavor-spin-orbital wave function for a positive parity Theta^+ that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive parity Theta^+ lighter than its negative parity counterpart. We consider decays of the Theta^+ and compute the overlap of this state with the kinematically allowed final states. Our results are numerically small. We note that dynamical correlations between quarks are not necessary to obtain narrow pentaquark widths.Comment: 10 pages, 1 figure, Revtex4, two-column format, version to be published in Phys. Rev. D, includes numerical estimates of decay width

Shot noise in resonant tunneling through a zero-dimensional state with a complex energy spectrum

We investigate the noise properties of a GaAs/AlGaAs resonant tunneling structure at bias voltages where the current characteristic is determined by single electron tunneling. We discuss the suppression of the shot noise in the framework of a coupled two-state system. For large bias voltages we observed super-Poissonian shot noise up to values of the Fano factor $\alpha \approx 10$.Comment: 4 pages, 4 figures, accepted for Phys. Rev.