Effects of Calcium Sulfate Whiskers on the Mechanical Properties and Light Transmittance of PE Greenhouse Films

Calcium sulfate whisker (CSW) is a kind of fiber crystal material with high orientation structure. The major goal of this research is to study the changes of mechanical properties and light transmittance of PE greenhouse film with different proportions of CSW. The experimental results show that the mechanical properties and light transmittance of PE/CSW films are enhanced compared with the pure PE. For PE/2%CSW, it shows a 18.6% increase in tear strength, a 3.1% increase in luminous transmittance and 17.7% increase in haze. The PE/5%CSW demonstrates a 12.8% higher in tensile strength, a 20.5% higher in tear strength, a 23.9% lower in luminous transmittance and a 53.0% higher in haze. This article gives a new formula to strengthen the mechanical properties of PE greenhouse films and finds the direction for the research and development of astigmatic covering film.

A spacecraft attitude manoeuvre planning algorithm based on improved policy gradient reinforcement learning

To solve the problem of spacecraft attitude manoeuvre planning under dynamic multiple mandatory pointing constraints and prohibited pointing constraints, a systematic attitude manoeuvre planning approach is proposed that is based on improved policy gradient reinforcement learning. This paper presents a succinct model of dynamic multiple constraints that is similar to a real situation faced by an in-orbit spacecraft. By introducing return baseline and adaptive policy exploration methods, the proposed method overcomes issues such as large variances and slow convergence rates. Concurrently, the required computation time of the proposed method is markedly reduced. Using the proposed method, the near optimal path of the attitude manoeuvre can be determined, making the method suitable for the control of micro spacecraft. Simulation results demonstrate that the planning results fully satisfy all constraints, including six prohibited pointing constraints and two mandatory pointing constraints. The spacecraft also maintains high orientation accuracy to the Earth and Sun during all attitude manoeuvres.

Revealing Electrical and Mechanical Performances of Highly Oriented Electrospun Conductive Nanofibers of Biopolymers with Tunable Diameter

The present study outlines a reliable approach to determining the electrical conductivity and elasticity of highly oriented electrospun conductive nanofibers of biopolymers. The highly oriented conductive fibers are fabricated by blending a high molar mass polyethylene oxide (PEO), polycaprolactone (PCL), and polylactic acid (PLA) with polyaniline (PANi) filler. The filler-matrix interaction and molar mass (M) of host polymer are among governing factors for variable fiber diameter. The conductivity as a function of filler fraction (φ) is shown and described using a McLachlan equation to reveal the electrical percolation thresholds (φc) of the nanofibers. The molar mass of biopolymer, storage time, and annealing temperature are significant factors for φc. The Young’s modulus (E) of conductive fibers is dependent on filler fraction, molar mass, and post-annealing process. The combination of high orientation, tunable diameter, tunable conductivity, tunable elasticity, and biodegradability makes the presented nanofibers superior to the fibers described in previous literature and highly desirable for various biomedical and technical applications.

NANOSATELLITE MOTION SIMULATION FOR TESTING THE SUN SENSOR

Nanosatellite (NS) began to perform complex missions that require high orientation. In this research, we developed a mathematical model of solar sensors to determine the orientation of a NS. Various moments of obtaining the angle of the sun's rays when they hit the solar sensors were presented. The test results of the solar sensors used to simulate various orbit scenarios are described in detail, and graphs of the solar sensor readings are plotted based on the results obtained. The article deals with modeling the motion of a NS in orbit. The NS is equipped with 6 solar panels. The VTS software was used to simulate the motion of the NS. Also, in the study of determining the orientation, two different problems were considered, that is, when the satellite is in the shadow part of the earth and when it is in the solar part of the earth. For these tasks, a mathematical model for determining the orientation was built. This method is very relevant for the study of small spacecraft.

Double Crystallization and Phase Separation in Polyethylene—Syndiotactic Polypropylene Di-Block Copolymers

Crystallization and phase separation in the melt in semicrystalline block copolymers (BCPs) compete in defining the final solid state structure and morphology. In crystalline–crystalline di-block copolymers the sequence of crystallization of the two blocks plays a definitive role. In this work we show that the use of epitaxial crystallization on selected crystalline substrates allows achieving of a control over the crystallization of the blocks by inducing crystal orientations of the different crystalline phases and a final control over the global morphology. A sample of polyethylene-block-syndiotactic polypropylene (PE-b-sPP) block copolymers has been synthesized with a stereoselective living organometallic catalyst and epitaxially crystallized onto crystals of two different crystalline substrates, p-terphenyl (3Ph) and benzoic acid (BA). The epitaxial crystallization on both substrates produces formation of highly ordered morphologies with crystalline lamellae of sPP and PE highly oriented along one direction. However, the epitaxial crystallization onto 3Ph should generate a single orientation of sPP crystalline lamellae highly aligned along one direction and a double orientation of PE lamellae, whereas BA crystals should induce high orientation of only PE crystalline lamellae. Thanks to the use of the two selective substrates, the final morphology reveals the sequence of crystallization events during cooling from the melt and what is the dominant event that drives the final morphology. The observed single orientation of both crystalline PE and sPP phases on both substrates, indeed, indicates that sPP crystallizes first onto 3Ph defining the overall morphology and PE crystallizes after sPP in the confined interlamellar sPP regions. Instead, PE crystallizes first onto BA defining the overall morphology and sPP crystallizes after PE in the confined interlamellar PE regions. This allows for discriminating between the different crystalline phases and defining the final morphology, which depends on which polymer block crystallizes first on the substrate. This work also shows that the use of epitaxial crystallization and the choice of suitable substrate offer a means to produce oriented nanostructures and morphologies of block copolymers depending on the composition and the substrates.

Green Marketing: An Analysis of Consumer’s Perception and Willingness to Pay

There has been a gush in the usage of the term ‘Green’, since people worldwide is becoming more concerned about their environment. Green marketing is an emerging strategy which encompasses the marketing of the products that are assumed to be environmentally safe. Rising environmental concern has persuaded consumers and manufacturers towards green marketing. This paper attempts to study the environmental orientation of the young Indian consumer and their perception about green marketing. Primary data collected from 100 consumers with the help of an online questionnaire was used for the study. The results revealed that consumers were having a high orientation towards the environment and the majority preferred green products over conventional products. More than half of the respondent consumers were willing to pay an additional 2-5 per cent of their actual price in case of green products. Consumers need to be made more aware about the issues that the product attempts to address. Green marketing should not be thought of as another approach for making profit. Rather it should be trailed with vigour, because of its ecological and social dimension.

Structure and Properties of Poly(ethylene terephthalate) Fiber Webs Prepared via Laser-Electrospinning and Subsequent Annealing Processes

Melt-electrospinning is an eco-friendly method for producing ultra-fine fibers without using any solvent. We prepared webs of poly(ethylene terephthalate) (PET) through melt-electrospinning using CO2 laser irradiation for heating. The PET webs comprised ultra-fine fibers of uniform diameter (average fiber diameter = 1.66 μm, coefficient of variation = 19%). The co-existence of fibers with high and low molecular orientation was confirmed through birefringence measurements. Although the level of high orientation corresponded to that of commercial highly oriented yarn, crystalline diffraction was not observed in the wide-angle X-ray diffraction (WAXD) analysis of the webs. The crystallinity of the webs was estimated using differential scanning calorimetry (DSC). The fibers with higher birefringence did not exhibit any cold crystallization peak. After annealing the web at 116 °C for 5 min, a further increase in the birefringence of the fibers with higher orientation was observed. The WAXD results revealed that the annealed webs showed crystalline diffraction peaks with the orientation of the c-axis along the fiber axis. In summary, the formation of fibers with a unique non-crystalline structure with extremely high orientation was confirmed.

Clustering Koreans’ Environmental Awareness and Attitudes into Seven Groups: Environmentalists, Dissatisfieds, Inactivators, Bystanders, Honeybees, Optimists, and Moderates

We attempted to characterize different groups of environmental awareness and attitudes and to interpret the public’s diverse interests in the environment. Responses of a five-year public survey in South Korea were clustered by k-means algorithms into the following seven groups: environmentalists, dissatisfieds, inactivators, bystanders, honeybees, optimists, and moderates. The environmentalists, who were dissatisfied with the status of the environment, had a strong orientation toward pro-environmental attitudes and practices. The inactivators revealed a discrepancy between high orientation in pro-environmental perception and attitude and weak participation in pro-environmental practices. The optimists and dissatisfieds stood distinct against each other, while the former were satisfied with the status of the environment and the environmental protection efforts of government and enterprises, the latter were not. The honeybees, who were older than others, had little knowledge of the environment but engaged in more environmental protection practices; the younger bystanders were less interested in environmental issues and practices. The moderates gave average answers to the overall questions. Cluster analysis could help in understanding the complex landscape of the public’s environmental awareness and attitudes beyond a straightforward scale from anti- to pro-environment and support the establishment of environmental policy customized to the different groups.