基于SolidWorks的全自动塑杯灌装封口机有限元分析

首先使用SolidWorks对全自动塑杯灌装封口机的各个模块进行三维实体建模,然后以该封口机左侧机体模块为研究对象,使用SolidWorks的COSMOSWorks有限元分析插件对其进行有限元分析,得出应力、应变、位移、安全系数图解,针对图解的结果,提出相应的改进措施,目的在于最大限度地缩短全自动塑杯灌装封口机的设计周期,降低测试成本,提高产品质量,加大利润空间,并为进一步进行优化设计提供了有效的途径。

全自动塑杯灌装封口机模块化参数化设计技术研究

以全自动塑杯灌装封口机为研究对象,基于CAD/CAE技术,研究了该封口机的模块化及参数化设计技术,目的在于提高该封口机设计的标准化,通用化程度,从而缩短其设计周期,降低其测试成本,而且还有利于实现多品种生产,能以相对较低的成本,快速满足市场多变的需要。

包装机模块化参数化设计方法研究

本论文以全自动塑杯灌装封口机这种包装机为研究对象，基于CAD／CAE技术，研究了该封口机的模块化及参数化设计技术，目的在于提高该封口机的标准化，通用化程度，缩短其设计周期，而且还有利于实现多品种生产，能以相对较低的成本，快速满足市场多变的需要。

固体办公胶水生产技术

固体办公胶水携带方便，使用起来干净、省事，深受消费者喜爱。其生产技术如下。

A Soil Temperature Control System for Sapling Study in Alpine Region

A soil temperature control system was designed for sapling study in alpine region and tested in summer, 2009. The system consisted of a power switch, voltage regulator, microcomputer timer, safety relays, temperature control device, temperature sensors, heating cables, fireproofing plastic pipes (PVC), 108 heavy-duty plastic containers and seedlings. The heating cables were held in six 2-layer PVC frames with 25 cm wide, 320 cm long and 25 cm high and three 1-layer frames with 25 cm wide and 320 cm long for 15°C soil temperature treatment, half of the 2-layer frames were used for 20°C and 25°C soil temperature treatments, respectively. Each of the frames was installed at each of ditches with 30 cm wide, 330 cm long and 30 cm deep in size. 12 seedling containers with 20 cm top diameter, 18cm bottom diameter and 25 cm high were homogenously placed at each of the ditches, and spaces between the containers were filled with natural soil. The system was economic, and could increase soil temperatures obviously and uniformly, the maximal and minimal standard errors of soil temperatures were ±0.28 and ±0.05°C at 10cm depth in the containers within each of all the ditches. In the system, aboveground environment was natural, diurnal and monthly soil temperatures varied with changing air temperature, the research results may be better to know the eco-physiological and growth responses of alpine saplings/seedlings to soil warming than that in greenhouse, laboratory, infrared heat lamp and open top chamber.

Simulation of bulk metal forming processes using one-step finite element approach based on deformation theory of plasticity

The bulk metal forming processes were simulated by using a one-step finite element(FE)approach based on deformation theory of plasticity,which enables rapid prediction of final workpiece configurations and stress/strain distributions.This approach was implemented to minimize the approximated plastic potential energy derived from the total plastic work and the equivalent external work in static equilibrium,for incompressibly rigid-plastic materials,by FE calculation based on the extremum work principle.The one-step forward simulations of compression and rolling processes were presented as examples,and the results were compared with those obtained by classical incremental FE simulation to verify the feasibility and validity of the proposed method.

Double linear strain distribution assumption of RC beam strengthened with external-bonded or near-surface mounted fiber reinforced plastic

Rehabilitation of existing structures with fiber reinforced plastic(FRP)has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high specific stiffness.The strain coordination results of 34 reinforced concrete beams(four groups)strengthened with different methods were presented including external-bonded or near-surface mounted glass or carbon FRP or helical rib bar in order to study the strain coordination of the strengthening materials and steel rebar of RC beam.Because there is relative slipping between concrete and strengthening materials(SM),the strain of SM and steel rebar of RC beam satisfies the double linear strain distribution assumption,that is,the strain of longitudinal fiber parallel to the neutral axis of plated beam within the scope of effective height(h0)of the cross section is in direct proportion to the distance from the fiber to the neutral axis.The strain of SM and steel rebar satisfies the equation εGCH=βεsteel,where the value of β is equal to 1.1-1.3 according to the test results.

Experimental study on slender reinforced concrete columns wrapped with CFRP

By axial compression tests on 6 reinforced concrete slender columns wrapped with carbon fiber-reinforced plastic (CFRP),with slenderness ratio(SR) from 4.5 to 17.5,the results show that when SR increases the retrofitting effect declines. In the case of same SR,the stability coefficient (SC) for the reinforced concrete(RC) columns with CFRP is much less than that without CFRP. There is 20% increase of stable bearing capacity to the former as compared with the latter when the SR in less than 17.5. The study summarized the simplified formula for SC,which provides a reference for engineering designers.

A triaxial creep model for coal containing gas and its stability analysis

Triaxial creep tests on CCG specimens were systematically performed using aself-made creep seepage experimental apparatus for determining the creep law of CCG.An improved triaxial creep model of CCG was established on the basis of a Nishiharamodel and another visco-elasto-plastic model,parameters of which were fitted on test data.Furthermore,the creep model is validated according to the result of triaxial creep experiments,and the outcome shows that the proposed triaxial creep model can properly characterizethe properties of various creep deformation phases of CCG,especially the acceleratingcreep phase.At the same time,the instability conditions of CCG were presentedbased on the discussion of the improved model's stability in terms of stability theories ofdifferential equation solution.

Consumer willingness to pay for plastic bags levy and willingness to accept eco-friendly alternatives in Botswana

Plastic bags, though commonly used for packaging of goods, are highly durable and non- biodegradable. Plastic bag litter serves as a negative environmental externality detrimental to animal health and natural beauty of the environment. In an effort to curtail the excessive use of plastic bags in Botswana, the government introduced a plastic levy targeted at consumers at retail points. This study uses primary data collected from 367 respondents randomly selected from six geospatially and purposively selected shopping malls to determine the consumers＇ willingness to pay （WTP） for continued plastic bag usage and their willingness to accept （WTA） to shift to eco-friendly alternatives. The results of the study revealed that open dumping and burning of plastic litter are more common in Maun than in Gaborone, It also showed that there is a significant relationship between the level of education and W＇FP. Further, there is a significant variation in income and education in respect to environmental awareness. The government should improve its efforts of sensitizing the public about the improper disposal of plastic bags.

Viscoelasto-plastic rheological experiment under circular increment step load and unload and nonlinear creep model of soft rocks

The viscoelastic-plastic creep experiments on soft ore-rock in Jinchuan Mine III were performed under circular increment step load and unload. The experimental data were analyzed according to instantaneous elastic strain, visco-elastic strain, instantaneous plastic strain and visco-plastic strain. The result shows that instantaneous deformation modulus tends to increase with the increase of creep stress; soft rocks enhance the ability to resist instantaneous elastic deformation and instantaneous plastic deformation during the multi-level of load and unload in the cyclic process. In respect of specimen JC1099, the ratio of visco-elastic strain to visco-plastic strain varies from 3.15 to 6.58, and the ratio has decreasing tendency with stress increase as a whole; creep deformation tends to be a steady state at low stress level; soft rocks creep usually embodies accelerated creep properties at high stress level. With the damaging variable and the hardening function introduced, a nonlinear creep model of soft rocks is established, in which the decay creep is described by the nonlinear hardening function H of viscidity coefficient. The model can describe the accelerated creep of soft rocks since the nonlinear damaging evolvement variable D of deformation parameter of rocks is introduced. Three stages of soft rocks creep can be described with the uniform creep equation in the nonlinear creep model. With this nonlinear creep model applied to the creep experiments of the ore-rock of Jinchuan Mine III, the nonlinear creep model＇s curves are in good agreement with experimental data.

Frame property of unequal storey height with specially shaped columns under cyclic loading

A 1/3-scale reinfored concrete(RC) frame of unequal storey height with specially shaped columns was tested under low frequency cyclic loading.The damage characteristic,bearing capacity,deformation capacity and ductility were analyzed.The restoring force model of the frame was obtained based on the study of the hysteresis curve measured in experiment,and the stiffness degeneration characteristics of every storey of the frame were analyzed.Finally the accumulated damage was analyzed with the damage assessment model.It is shown that the seismic behavior of this frame of unequal storey height with specially shaped columns is generally good,but the bottom of first floor column is a weak part,which should be paid more attention in design,and the restoring force model derived from this experiment can be seen as a valuable guide for design and non-linear finite element analysis for this kind of structure.

奶业振兴的道路

我国奶业的发展可谓一日千里,回顾2000年国际奶业大会,奶业专家已经指出我国奶业正面临着新的发展机遇。首先,乳及乳制品市场空前繁荣。特别是近年来“牛奶科学论坛”、“国际牛奶日”、“乳及乳制品营养周”等引导消费活动的开展。再者,政府正掀起一个全民喝奶的“运动”:在今年5月的“中国学生奶推广活动”,为中小学生提供质优、价廉、安全的牛奶,促使学生养成天天喝奶的习惯,以提高我国学生身体素质和健康水平。此外,在今年11月举行的“第二届亚太地区学生奶会议”将重点讨论及交流推广学生奶的经验,从而促进学生奶事业的发展。由此可见,乳品发展,前途无限。 要振兴奶业,必须以科学研究。

Effect of an escape vent in accordion-shaped traps on the catch and size of Asian paddle crabs Charybdis japonica in an artificial reef area

Accordion-shaped traps are widely used in China to catch the Asian paddle crab C harybdis japonica but traps of conventional design often catch juvenile crabs. A new type of accordion-shaped trap with an escape vent(L×W=4.3 cm×3.0 cm) was designed and a comparative study between the newly designed and conventional traps was performed in the artifi cial reef area of Zhuwang, Laizhou Bay, China from June to August 2012. The mean catch per unit effort(CPUE) of undersized crabs was signifi cantly lower in the vented traps than in the conventional traps(paired t-test, n =30, P <0.001), while the CPUE of marketable crabs was signifi cantly higher in the vented traps(paired t-test, n =30, P <0.001). The mean size of crabs(carapace length) caught in the vented traps was signifi cantly larger than in conventional traps(paired t-test, n =29, P <0.001). The ratio of undersized crabs was 35.05%±2.57% in conventional traps and 12.53%±0.69% in vented traps(signifi cantly lower, paired t-test, n =29, P <0.001). Therefore, a 4.3 cm×3.0 cm escape vent was considered appropriate for C. japonica fi shing in the artifi cial reef area. This fi nding will assist the development of more sustainable and effi cient crab fi shing methods using accordion-shaped traps.

Co-processing Vacuum Residue with Waste Plastics in a Delayed Coking Process:Kinetics and Modeling

Thermal upgrading of vacuum residue mixed with waste plastics was studied in a laboratory scale delayed coking unit.The model of feed thermal decomposition was set up and the first order reaction kinetics was used to predict products distribution during the coking process.The distillate yield was higher(70%) for the vacuum residue/polystyrene(VR/PS) feed system and the vacuum residue/low density polyethylene(VR/LDPE) feed system.The resulted distillate yield was separated into fractions according to their boiling points,with gasoline and diesel being our fractions of concern.The activation energy was higher for gasoline production(around 60 kcal/mol) varying with the type of feed system,while it was 33 kcal/mol for diesel fraction.The regression coefficient R was 0.990.

Life Cycle Assessment of Biodegradable Polylactic Acid(PLA)Plastic Packaging Products—Taking Tianjin,China as a Case Study

In this paper, the life cycle assessment(LCA) method is used to evaluate and quantify the energy consumption and environmental impacts of biodegradable polylactic acid(PLA) plastic packaging from the five stages of raw material acquisition, raw material transportation, product production, products use and final disposal. Seven impact categories were selected for the impact analysis: abiotic depletion potential fossil fuels(ADP), global warming potential(GWP), acidification potential(AP), eutrophication potential(EP), photochemical ozone formation potential(POCP), human toxicity potential(HTP), and terrestrial ecotoxicity potential(TETP). The results of the LCA are discussed and the results show that production of products is the highest stage of the environmental impact. Meanwhile, in the entire life cycle, the top three environmental impact categories are GWP, ADP and HTP,which account for 32.63%, 24.83% and 14.01%, respectively. The LCA results show that the environmental impact can be reduced in several ways: reducing the consumption of electricity, increasing the input of new energy, increasing the conversion rate of materials in the production process, using organic and water-soluble fertilizers instead of conventional fertilizers, using environment-friendly fuels and establishing a sound recycling system.

Roles of chromatin assembly factor 1 in the epigenetic control of chromatin plasticity

Genetic information embedded in DNA sequence and the epigenetic information marked by modifications on DNA and his- tones are essential for the life of eukaryotes. Cells have evolved mechanisms of DNA duplication and chromatin restoration to ensure the inheritance of genetic and epigenetic information during cell division and development. In this review, we focus on the maintenance of epigenetic landscape during chromatin dynamics which requires the orchestration of histories and their chaperones. We discuss how epigenetic marks are re-established in the assembly of new chromatin after DNA replication and repair, highlighting the roles of CAF-1 in the process of changing chromatin state. The functions of CAF-1 provide a link be- tween chromatin assembly and epigenetic restoration.

Experimental study of the flow and heat transfer of a gas–water mixture through a packed channel

Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue gas.The experiments measured the effects of inlet air temperature, inlet air velocity and circulating water flow rate on the flow and heat transfer. The results show that higher inlet air temperatures and lower inlet air velocities lower the flow resistance and increase the heat transfer coefficient. The stainless steel packing had better surface wettability and larger thermal conductivity than the plastic packing, which enhanced the heat transfer between the water and the saturated moist air. When both the flow resistance reduction and the heat transfer enhancement were considered, the experimental results gave an optimal packing-specific surface area. A packed heat exchanger tower was designed for waste heat recovery from the flue gas of gas-fired boilers based on the experimental results which had better flow and heat transfer characteristics with lower pump and fan power consumption, more stable system operation and less thermal fluctuations compared with a non-packed heat transfer system with atomized water.

A constitutive model for granular materials considering grain breakage

A particle breakage has a significant impact on the mechanical behavior of granular materials. In this paper, we present an elasto-plastic model with two yield surfaces to which the influence of particle breakage has been introduced. The main feature of this model is to incorporate the change in the critical state line (CSL) consequent to the grain breakage induced by isotropic and deviatoric stresses during loading. For this purpose we propose a breakage function which connects the evolution of the CSL to the energy consumed. Results from earlier studies on drained and undrained compression and extension triaxial tests were used to calibrate and validate the model. Comparison between earlier results and our simulations indicates that the model can reproduce with good accuracy the mechanical behavior of crushable granular materials and predict the evolution of the grain size distribution during loading.