The Impact of Strategy on Sharing Economy Companies: Lessons for Mobike

The sharing economy is growing rapidly these years, and has changed the lifestyle of citizens that the unoccupied resources can be shared to others who are need them to create new values through the online platforms (Fang, Ye, Law 2016). People is now emphasizing on the right of use instead of the ownership, and used to the sharing taxi, short rental even the bicycles which appeared from 2016 in China (Zhou, W. 2017). The sharing bicycle is used to solve the ‘last one mile’ after the subway and the short-distance daily trip in the first and second-tier cities (Ge 2017 and Xue 2016), moreover, the most successful sharing bicycle firms now are Mobike and OFO. However, there are several problems of this industry, for example, unprofitability operation, heavy competition, no differentiation of the products, etc.. This paper has made a research with the customers of Mobike, by using interview as the methodology, in order to obtain the opinions, feelings and advices from the consumers. Besides, using the PEST analysis and two of Porter’s five forces to analyse the external and internal competitive condition and the reasons of why the industry of Mobike is unprofitability status. In addition, analysing the products, profitability strategy, brand strategy and so on of the top two famous and successful previous sharing economy firms which are Uber and Airbnb. What’s more, this paper also included the analysis of OFO the main competitor of Mobike to explore the problems of the sharing bike industry and why OFO are more popular than Mobike in some area

Direct solution of Navier-Stokes equations by using an upwind local RBF-DQ method

The differential quadrature (DQ) method is able to obtain quite accurate numerical solutions of differential equations with few grid points and less computational effort. However, the traditional DQ method is convenient only for regular regions and lacks upwind mechanism to characterize the convection of the fluid flow. In this paper, an upwind local radial basis function-based DQ (RBF-DQ) method is applied to solve the Navier-Stokes equations, instead of using an iterative algorithm for the primitive variables. The non-linear collocated equations are solved using the Levenberg-Marquardt method. The irregular regions of 2D channel flow with different obstructions situations are considered. Finally, the approach is validated by comparing the results with those obtained using the well-validated Fluent commercial package

Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation

A three-dimensional computational fluid dynamics (CFD) model of a labyrinth seal was established in order to investigate the influence mechanism of combined effects between bearings and labyrinth seals on the dynamic characteristics of the rotor-bearing-seal system. The dynamic coefficients of the labyrinth seal for various rotating speeds were calculated. Results show that the absolute values of cross-coupled coefficients increase with the increasing rotating speed, while the absolute values of direct coefficients decrease slightly. The positive preswirl at the inlet tends to intensify the increase of cross-coupled coefficients and the decrease of direct coefficients. The negative preswirl shows the opposite effect. A finite element model was further setup. Results show that the labyrinth seal has a large influence on the synchronous response of rotor in the resonant region due to its damping effect. For other speeds, it has a minor effect. The labyrinth seal may promote the instability of the rotor-bearing-seal system. The subsynchronous vibration increases significantly when the seal force is taken into account. The system stability can be generally enhanced by introducing the negative preswirl at the inlet. Results also show that the detrimental influence of the labyrinth seal can be compensated by using suitable bearings. A proper bearing configuration can be designed to reduce the risks of rotordynamic instabilities due to seals. An experimental test was finally performed, and it shows good agreements with the numerical simulation

Influence of tilting rotor on characteristics of fluid-induced vibration for labyrinth seals

Labyrinth seal is a key component for the safe and reliable operation of a turbine unit. This paper sets up a three-dimensional numerical model of a labyrinth seal with a tilting rotor based on a compressor eye seal which was studied by Computational Fluid Dynamics method and a test labyrinth seal. The influence of the tilting rotor on the static and dynamic characteristics of labyrinth seals was investigated. Numerical results demonstrated a good agreement with the published article. Both the radial and tangential fluid-induced forces show an obvious increase when the rotor is in tilting conditions. From an efficiency viewpoint, a bigger tilt angle of the rotor is desirable. And eccentricity existence is not beneficial to the seal performance. The results based on the test seal show the whirl frequency ratio increases with the increasing eccentricity ratio. In case of tilting conditions (δ= 0.05 mm, θ= 0.8 deg), the whirl frequency ratio decreases with the increasing rotational speed. The higher rotational speed will be beneficial to the stability improvement when the rotor is in tilting conditions. The whirl frequency ratio also shows a decrease with the increasing inlet pressure. The higher inlet pressure tends to improve the stability when the rotor is in tilting conditions. All the stiffness coefficients and damping coefficients increase as the tilt angle increases. The whirl frequency ratio also shows an increase with the increasing tilt angle. The tilting rotor tends to reduce the stability when the rotor is in eccentric conditions

Identification of Topping Responsive Proteins in Tobacco Roots

Tobacco plant has many responses to topping, such as the increase in ability of nicotine synthesis and secondary growth of roots. Some topping responsive miRNAs and genes had been identified in our previous work, but it is not enough to elaborate mechanism of tobacco response to topping. Here, topping responsive proteins were screened from tobacco roots with two-dimensional electrophoresis. Of these proteins, calretulin (CRT) and Auxin-responsive protein IAA9 were related to the secondary growth of roots, LRR disease resistance, heat shock protein 70 and farnesyl pyrophosphate synthase 1（FPPS）were involved in wounding stress response, and F-box protein played an important role in promoting the ability of nicotine synthesis after topping. In addition, there were five tobacco bHLH proteins (NtbHLH, NtMYC1a, NtMYC1b, NtMYC2a and NtMYC2b) related to nicotine synthesis. It was suggested that NtMYC2 might be the main positive transcription factor and NtbHLH protein is a negative regulator in the JA-mediating activation of nicotine synthesis after topping. Tobacco topping activates some comprehensive biology processes involving IAA and JA signaling pathway, and the identification of these proteins will be helpful to understand the process of topping response

Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation

A three-dimensional computational fluid dynamics (CFD) model of a labyrinth seal was established in order to investigate the influence mechanism of combined effects between bearings and labyrinth seals on the dynamic characteristics of the rotor-bearing-seal system. The dynamic coefficients of the labyrinth seal for various rotating speeds were calculated. Results show that the absolute values of cross-coupled coefficients increase with the increasing rotating speed, while the absolute values of direct coefficients decrease slightly. The positive preswirl at the inlet tends to intensify the increase of cross-coupled coefficients and the decrease of direct coefficients. The negative preswirl shows the opposite effect. A finite element model was further setup. Results show that the labyrinth seal has a large influence on the synchronous response of rotor in the resonant region due to its damping effect. For other speeds, it has a minor effect. The labyrinth seal may promote the instability of the rotor-bearing-seal system. The subsynchronous vibration increases significantly when the seal force is taken into account. The system stability can be generally enhanced by introducing the negative preswirl at the inlet. Results also show that the detrimental influence of the labyrinth seal can be compensated by using suitable bearings. A proper bearing configuration can be designed to reduce the risks of rotordynamic instabilities due to seals. An experimental test was finally performed, and it shows good agreements with the numerical simulation

Improving the rotordynamic stability of short labyrinth seals using positive preswirl

Introducing a negative preswirl at the upstream of annular gas seals has been considered as an effective way to improve the system stability. This paper demonstrates a stability enhancement approach for a short labyrinth seal using positive preswirls. The static and dynamic characteristics of the labyrinth seal with various blade numbers (5, 10, 15), inlet preswirl ratios (–0.3, –0.15, 0, 0.15, 0.3) were studied. Results show that the inlet preswirl ratio has a dramatic effect on the circumferential location of the high-pressure spot for each seal cavity, particularly for the first cavity. The inlet preswirl ratio has opposite effects on the system stability due to the difference of high-pressure spot locations between the first cavity and the others. An increasing positive inlet preswirl could improve the system stability for the labyrinth seal with fewer blades (e.g. 5 blades). Its characteristics is mainly dominated by the first seal cavity. For the labyrinth seal with 10 blades, the system characteristics shows slight dependency on the inlet preswirl ratio. For the labyrinth seal with more blades (e.g. 15 blades), the negative inlet preswirl still increases the system stability, which agrees with the conventional conclusion. The paper provides a deeper understanding on the stability improvement of the labyrinth seal

STUDY ON ANTI-EHRLICH ASCITES TUMOUR EFFECT OF PINELLIA TERNATA POLYSACCHARIDE IN VIVO

The objectives of the study were to investigate the anti-tumour activity of Pinellia ternata polysaccharide in vivo, and to preliminarily explore the possible mechanism of its antitumour action. Mouse model of Ehrlich ascites tumour (solid tumour) was used to detect the serum SOD, MDA and GSH-Px levels in mouse and to measure the tumour inhibition rate and survival prolongation rate. The results showed that Pinellia ternata polysaccharide had some tumour inhibitory effect. Tumour weight of Pinellia ternata polysaccharide high-dose group was highly significantly different (

Plant Phenotypic Traits Eventually Shape Its Microbiota: A Common Garden Test

Plant genotype drives the development of plant phenotypes and the assembly of plant microbiota. The potential influence of the plant phenotypic characters on its microbiota is not well characterized and the co-occurrence interrelations for specific microbial taxa and plant phenotypic characters are poorly understood. We established a common garden experiment, which quantifies prokaryotic and fungal communities in the phyllosphere and rhizosphere of six spruce (Picea spp.) tree species, through Illumina amplicon sequencing. We tested for relationships between bacterial/archaeal and fungal communities and for the phenotypic characters of their plant hosts. Host phenotypic characters including leaf length, leaf water content, leaf water storage capacity, leaf dry mass per area, leaf nitrogen content, leaf phosphorous content, leaf potassium content, leaf δ13C values, stomatal conductance, net photosynthetic rate, intercellular carbon dioxide concentration, and transpiration rate were significantly correlated with the diversity and composition of the bacterial/archaeal and fungal communities. These correlations between plant microbiota and suites of host plant phenotypic characters suggest that plant genotype shape its microbiota by driving the development of plant phenotypes. This will advance our understanding of plant-microbe associations and the drivers of variation in plant and ecosystem function

The Impact of Strategy on Sharing Economy Companies: Lessons for Mobike

The sharing economy is growing rapidly these years, and has changed the lifestyle of citizens that the unoccupied resources can be shared to others who are need them to create new values through the online platforms (Fang, Ye, Law 2016). People is now emphasizing on the right of use instead of the ownership, and used to the sharing taxi, short rental even the bicycles which appeared from 2016 in China (Zhou, W. 2017). The sharing bicycle is used to solve the ‘last one mile’ after the subway and the short-distance daily trip in the first and second-tier cities (Ge 2017 and Xue 2016), moreover, the most successful sharing bicycle firms now are Mobike and OFO. However, there are several problems of this industry, for example, unprofitability operation, heavy competition, no differentiation of the products, etc.. This paper has made a research with the customers of Mobike, by using interview as the methodology, in order to obtain the opinions, feelings and advices from the consumers. Besides, using the PEST analysis and two of Porter’s five forces to analyse the external and internal competitive condition and the reasons of why the industry of Mobike is unprofitability status. In addition, analysing the products, profitability strategy, brand strategy and so on of the top two famous and successful previous sharing economy firms which are Uber and Airbnb. What’s more, this paper also included the analysis of OFO the main competitor of Mobike to explore the problems of the sharing bike industry and why OFO are more popular than Mobike in some area