Study on Preventive Maintenance Strategies of Filling Equipment Based on Reliability-Cantered Maintenance

In order to ensure normal operation of enterprise production activities and enhance the competitiveness of enterprise, equipment management and maintenance strategy formulation has always been one of important contents of daily management of enterprise. According to the actual requirement of a Chinese beer production enterprise, preventive maintenance strategy of filling equipment is put forward based on reliability-centred maintenance (RCM). Firstly, on the basis of analyzing RCM theory and equipment maintenance, the general process of failure analysis of beer production equipment is presented. Secondly, the general production process of bottled beer is analyzed, and the composition of major filling equipment is also introduced in the beer production line. With the help of key indicators of equipment reliability, such as mean time between failure (MTBF), mean time to repair restoration (MTTR) and availability Ai, the fault analysis of filling production line is carried out, and the relevant results are calculated. Then, process failure mode and effect analysis (PFMEA) of filling machine is implemented, and fault tree analysis (FTA) of potential failure modes with high risk priority numbers is also completed. Finally, preventive and maintenance strategies of filling equipment are established on the basis of RCM. Through the research in this paper, maintenance costs and unplanned breakdown hours can be significantly reduced

cmdABCDEF, a cluster of genes encoding membrane proteins for differentiation and antibiotic production in Streptomyces coelicolor A3(2)

<p>Abstract</p> <p>Background</p> <p><it>Streptomyces coelicolor </it>is the most studied <it>Streptomyces </it>species and an excellent model for studying differentiation and antibiotic production. To date, many genes have been identified to be required for its differentiation (e.g. <it>bld </it>genes for aerial growth and <it>whi </it>genes for sporulation) and antibiotics production (including <it>actII-orf4</it>, <it>redD</it>, <it>cdaR </it>as pathway-specific regulatory genes and <it>afsR</it>, <it>absA1/A2 </it>as pleiotropic regulatory genes).</p> <p>Results</p> <p>A gene cluster containing six genes (<it>SCO4126-4131</it>) was proved to be co-transcribed in <it>S. coelicolor</it>. Deletions of <it>cmdABCDEF </it>(<it>SCO4126-4131</it>) displayed defective sporulation including formation of aberrant branches, and abnormalities in chromosome segregation and spore septation. Disruption mutants of apparently orthologous genes of <it>S. lividans </it>and <it>S. avermitilis </it>also showed defective sporulation, implying that the role of these genes is similar among <it>Streptomyces</it>. Transcription of <it>cmdB</it>, and therefore presumably of the whole operon, was regulated developmentally. Five of the encoded proteins (CmdA, C, D, E, F) were predicted membrane proteins. The other, CmdB, a predicted ATP/GTP-binding protein with an ABC-transporter-ATPase domain shown here to be essential for its function, was also located on the cell membrane. These results indicate that CmdABCDEF proteins mainly affect <it>Streptomyces </it>differentiation at an early stage of aerial hyphae formation, and suggest that these proteins may form a complex on cell membrane for proper segregation of chromosomes. In addition, deletions of <it>cmdABCDEF </it>also revealed over-production of blue-pigmented actinorhodin (Act) via activation of transcription of the pathway-specific regulatory gene <it>actII-orf4 </it>of actinorhodin biosynthesis.</p> <p>Conclusion</p> <p>In this study, six co-transcribed genes <it>cmdABCDEF </it>were identified by their effects on differentiation and antibiotic production in <it>Streptomyces coelicolor </it>A3(2). These six membrane-located proteins are possibly assembled into a complex to function.</p

Tuning the electronic properties of monolayer and bilayer PtSe\u3csub\u3e2\u3c/sub\u3e \u3ci\u3evia\u3c/i\u3e strain engineering

The recently synthesized monolayer PtSe2 belongs to the class of two-dimensional transition metal dichalcogenide (TMDC) materials (Nano Lett., 2015, 15, 4013). Based on first-principles calculations, we show that the band gaps of monolayer and bilayer PtSe2 can be tuned over a wide range via strain engineering. Both isotropic and uniaxial strains are investigated. For bilayer PtSe2, the vertical out-of-plane strain is also considered. In most cases, the strain can reduce the band gap except for the bilayer PtSe2 under the isotropic strain (Ɛ≤ 4%) for which the band gap can be slightly enlarged. Importantly, the monolayer can be transformed from the indirectgap to the direct-gap semiconductor at the compressive strain of Ɛy = -8%. Moreover, the bilayer can undergo the semiconductorto- metal (S–M) transition at a critical vertical strain due to the chemical interaction (p orbital coupling) between the Se atoms of the two opposite layers. Overall, the ability to modulate the band gap of monolayer and bilayer PtSe2 over an appreciable range of strains opens up new opportunities for their applications in nanoelectronic devices

Estimating global cropland production from 1961 to 2010

Global cropland net primary production (NPP) has tripled over the last 50 years, contributing 17–45 % to the increase in global atmospheric CO2 seasonal amplitude. Although many regional-scale comparisons have been made between statistical data and modeling results, long-term national comparisons across global croplands are scarce due to the lack of detailed spatiotemporal management data. Here, we conducted a simulation study of global cropland NPP from 1961 to 2010 using a process-based model called Vegetation–Global Atmosphere–Soil (VEGAS) and compared the results with Food and Agriculture Organization of the United Nations (FAO) statistical data on both continental and country scales. According to the FAO data, the global cropland NPP was 1.3, 1.8, 2.2, 2.6, 3.0, and 3.6 PgC yr−1 in the 1960s, 1970s, 1980s, 1990s, 2000s, and 2010s, respectively. The VEGAS model captured these major trends on global and continental scales. The NPP increased most notably in the US Midwest, western Europe, and the North China Plain and increased modestly in Africa and Oceania. However, significant biases remained in some regions such as Africa and Oceania, especially in temporal evolution. This finding is not surprising as VEGAS is the first global carbon cycle model with full parameterization representing the Green Revolution. To improve model performance for different major regions, we modified the default values of management intensity associated with the agricultural Green Revolution differences across various regions to better match the FAO statistical data at the continental level and for selected countries. Across all the selected countries, the updated results reduced the RMSE from 19.0 to 10.5 TgC yr−1 (∼  45 % decrease). The results suggest that these regional differences in model parameterization are due to differences in socioeconomic development. To better explain the past changes and predict the future trends, it is important to calibrate key parameters on regional scales and develop data sets for land management history

Coordinating a multi-retailer decentralized distribution system with random demand based on buyback and compensation contracts

Purpose: The purpose of this paper is to set up the coordinating mechanism for a decentralized distribution system consisting of a manufacturer and multiple independent retailers by means of contracts. It is in the two-stage supply chain system that all retailers sell an identical product made by the manufacturer and determine their order quantities which directly affect the expected profit of the supply chain with random demand. Design/methodology/approach: First comparison of the optimal order quantities in the centralized and decentralized system shows that the supply chain needs coordination. Then the coordination model is given based on buyback cost and compensation benefit. Finally the coordination mechanism is set up in which the manufacturer as the leader uses a buyback policy to incentive these retailers and the retailers pay profit returns to compensate the manufacturer. Findings: The results of a numerical example show that the perfect supply chain coordination and the flexible allocation of the profit can be achieved in the multi-retailer supply chain by the buyback and compensation contracts. Research limitations: The results based on assumptions might not completely hold in practice and the paper only focuses on studying a single product in two-stage supply chain Practical implications: The coordination mechanism is applicable to a realistic supply chain under a private information setting and the research results is the foundation of further developing the coordination mechanism for a realistic multi-stage supply chain system with more products. Originality/value: This paper focused on studying the coordination mechanism for a decentralized multi-retailer supply chain by the joint application of the buyback and compensation contracts. Furthermore the perfect supply chain coordination and the flexible allocation of the profit are achieved.Peer Reviewe