Kinds Of Plastics Research Articles

Ecologically Сlean Packaging — Edible Film Based on Apple Puree with the Addition of Sodium Alginate

Properties of such "active" shells as edible film materials have been studied. The basis of these coatings are natural polymers - polysaccharides, which can be represented by sodium alginate. Edible films based on natural polymers have a high sorption ability and, when ingested, adsorb and remove metal ions, radionuclides and other harmful substances from the human body. The organoleptic properties, structure, water-absorbing capacity, strength characteristics of double edible films based on apple puree, with inclusion of sodium alginate in one of the layers were studied. Five samples of a film with various kinds of plasticizers were made. It is established that all the films obtained possess good digestibility by the organism due to the content of completely natural components.

Ag/SiO2 surface-enhanced Raman scattering substrate for plasticizer detection

In this study, we demonstrated a simple method of fabricating a high-performance surface-enhanced Raman scattering (SERS) substrate. Monodispersive SiO2 colloidal spheres were self-assembled on a silicon wafer, and then a silver layer was coated on it to obtain a Ag/SiO2 SERS substrate. The Ag/SiO2 SERS substrates were used to detect three kinds of plasticizer with different concentrations, namely, including bis(2-ethylhexyl)phthalate (DEHP), benzyl butyl phthalate (BBP), and dibutyl phthalate (DBP). The enhancement of Raman scattering intensity caused by surface plasmon resonance can be observed using the Ag/SiO2 SERS substrates. The Ag/SiO2 SERS substrate with a 150-nm-thick silver layer can detect plasticizers, and it satisfies the detection limit of plasticizers at 100 ppm. The developed highly sensitive Ag/SiO2 SERS substrates show a potential for the design and fabrication of functional sensors to identify the harmful plasticizers that plastic products release in daily life.

Raman rapid detection of environmental hormone

Diethylhexyl phthalate(DEHP) is a kind of plasticizer，which is regarded as environmental hormone due to reproductive toxicity to human body and also has the risk of breast cancer, endometrial cancer and liver cancer after long-term intake. In this work, a rapid surface enhanced Raman scattering (SERS) technique to detect the DEHP residue level in food products is developed by optimizing the synthesis of a hexakisphosphate (IP6) stabilized Au@Ag@IP6 nanoparticles. For further improvement of detection sensitivity, such SERS substrate is treated by using 1-dodecanethiol (DT) to enable its capability of capturing more DEHP molecules into the vicinity of SERS hot spots. Au@Ag@IP6/DT-based Raman protocol could analyze DEHP down to 10−8 M. By using a portable Raman system, the simple and reliable SERS method is used to on-site determine trace DEHP in real sample of energy drinks, which meets the requirement of national standard.

Selective and sensitive onsite detection of phthalates in common solvents

Phthalates, which are proven to have adverse health effects, are globally restricted for use in all kinds of plastics through various regulations. Although there are laboratory based techniques for phthalate detection, there is a pressing need for a field based technique so samples can be pre-screened. Here, we report a molecularly imprinted polymer (MIP) functionalized extended gate field effect transistor (EGFET) as a field sensor to identify di-2-ethlyhexyl phthalate (DEHP), which is the one of the most commonly used phthalate. In DI water, DEHP is detected at the extremely low concentration of 25 μg/L while exhibiting excellent selectivity. We are able to tune the linear dynamic range of the sensor by synthesizing the MIP with a different monomer-to-template ratio and by choice of the functional monomer. Finally, the sensor is calibrated for DEHP in artificial saliva at sub 50 μg/L, showing applicability in phthalate migration tests, which are used in assessing the safety of plastic toys. Furthermore, our sensor platform can be further extended to identify other phthalates as fast pre-screening tool.

Focus on materials, semiconductors, vacuum, and cryogenics

Focus on materials, semiconductors, vacuum, and cryogenics

Coexistence of Multiple Types of Synaptic Plasticity in Individual Hippocampal CA1 Pyramidal Neurons.

Understanding learning and memory mechanisms is an important goal in neuroscience. To gain insights into the underlying cellular mechanisms for memory formation, synaptic plasticity processes are studied with various techniques in different brain regions. A valid model to scrutinize different ways to enhance or decrease synaptic transmission is recording of long-term potentiation (LTP) or long-term depression (LTD). At the single cell level, spike timing-dependent plasticity (STDP) protocols have emerged as a powerful tool to investigate synaptic plasticity with stimulation paradigms that also likely occur during memory formation in vivo. Such kind of plasticity can be induced by different STDP paradigms with multiple repeat numbers and stimulation patterns. They subsequently recruit or activate different molecular pathways and neuromodulators for induction and expression of STDP. Dopamine (DA) and brain-derived neurotrophic factor (BDNF) have been recently shown to be important modulators for hippocampal STDP at Schaffer collateral (SC)-CA1 synapses and are activated exclusively by distinguishable STDP paradigms. Distinct types of parallel synaptic plasticity in a given neuron depend on specific subcellular molecular prerequisites. Since the basal and apical dendrites of CA1 pyramidal neurons are known to be heterogeneous, and distance-dependent dendritic gradients for specific receptors and ion channels are described, the dendrites might provide domain specific locations for multiple types of synaptic plasticity in the same neuron. In addition to the distinct signaling and expression mechanisms of various types of LTP and LTD, activation of these different types of plasticity might depend on background brain activity states. In this article, we will discuss some ideas why multiple forms of synaptic plasticity can simultaneously and independently coexist and can contribute so effectively to increasing the efficacy of memory storage and processing capacity of the brain. We hypothesize that resolving the subcellular location of t-LTP and t-LTD mechanisms that are regulated by distinct neuromodulator systems will be essential to reach a more cohesive understanding of synaptic plasticity in memory formation.

T013 What do we learn from the interaction between physical activities and effects of transcranial brain stimulation?

Several forms of transcranial brain stimulation have been developed to produce after-effects on the cortical excitability outlasting the stimulation itself for a period of time in the conscious human’s brain. Several lines of evidence suggest that transcranial brain stimulation change the excitability of the neuronal circuits through plasticity-like mechanisms. Such plasticity that is induced by transcranial brain stimulation in the motor cortex can be modulated by voluntary contraction that has no plasticity effect on its own. Not only the timing, but also the pattern of contraction is known to be crucial in determining the amount and direction of plasticity happening around the movement. Moreover, brief tonic voluntary contraction could modify plasticity induced in the motor cortex controlling the antagonist muscle, indicating not only the activity in the targeting area, but also that in a remote area connecting to this area, could modulate the effect of transcranial brain stimulation. Similar interactions have been also found in the visual cortex. The interaction between physical activities and the effects of transcranial brain stimulation may be explained by metaplasticity and reversal of plasticity, i.e. depotentiation and de-depression, and suggests that the physiological activity and synapses work synergistically in learning. The physiological activity during practice may fine tune the amount and direction of plasticity to improve learning. However, when a specific kind of plasticity is aimed to induce, the physiological activity should be well controlled to maintain a predictable result. In summary, the modulation effect of physical activities on the after-effect of transcranial brain stimulation has opened a door to further understand physiological mechanism of learning. On the other hand, by learning from such influence on the after-effect, the state of neuronal activity should be carefully controlled for a stable and predictable effect of transcranial brain stimulation.

Investigation on Variation of Bow Defect in Roll Forming Process

Roll forming is a kind of plastic forming process in which a steel strip is bent by several sets of rolls gradually into the desired shape. The products are cold roll forming steels with various sections. Roll forming is one of the most widely used processes in the world for forming metal. Roll forming is a complex deformation process, which involves large displacement, finite strain and the problems of contact and friction between strip and rolls. This process exhibits obvious geometry, physical and boundary nonliterary. The complex processes contain many aspects such as geometry, kinematics and dynamics, etc. The forming process involves not only transverse bending, but also other additional deformations. In this paper, a group of simulations have been established with ABAQUS software to studying about the spring back and bow defect in the roll forming process. At last, experiments have been accomplished to verify the simulation results. The simulations based on the ABAQUS software calculate the spring back angles and bow displacements. The bow displacement of the roll forming process is considered relate to many factors include inner distance between stands, gaps of the rolls, channel width, the material of the sheet, sheet thickness and so on.To verify the bow displacement in roll forming process, 9 groups of simulations were set up use Taguchi method to figure out the influence on bow displacement of every factor. The longitudinal strain also has been learned in the present study.

Effect of materials on the noise of a water hydraulic pump used in submersible

Open-circle sea water hydraulics, utilizing surrounding water as a working medium, has become more and more popular in submersible. Axial piston pump with port valves is used frequently in the open-circle water hydraulic system. Port valve is one of the important parts in this type pump. However, there are few literatures about the effect of the port valves’ materials on the noise characteristic of the water pump. In this study, the effect of materials on the noise of the pump was researched through experimental and theory simulation methods. The influences of three kinds of plastics (Polyetheretherketone (PEEK), Polytetrafluoroethylene (PTFE), Aliphatic polyamides (NYLON)) and one kind of anti-corrosion stainless steel (316L) are compared. The noise of the pump with the different materials port valve seat ranges from high to low as the order: 316L>NYLON>PEEK>PTFE. The differences would contribute to the collision between valve spool and seat, which is identified by the simulating results. The experimental results showed that the difference of noise between PEEK and PTFE is small. In addition, the lifespan and volumetric efficiency are also taken into considering. The PEEK is selected to use in the seawater pump for a large submersible.

Task-specific reorganization of the auditory cortex in deaf humans

The principles that guide large-scale cortical reorganization remain unclear. In the blind, several visual regions preserve their task specificity; ventral visual areas, for example, become engaged in auditory and tactile object-recognition tasks. It remains open whether task-specific reorganization is unique to the visual cortex or, alternatively, whether this kind of plasticity is a general principle applying to other cortical areas. Auditory areas can become recruited for visual and tactile input in the deaf. Although nonhuman data suggest that this reorganization might be task specific, human evidence has been lacking. Here we enrolled 15 deaf and 15 hearing adults into an functional MRI experiment during which they discriminated between temporally complex sequences of stimuli (rhythms). Both deaf and hearing subjects performed the task visually, in the central visual field. In addition, hearing subjects performed the same task in the auditory modality. We found that the visual task robustly activated the auditory cortex in deaf subjects, peaking in the posterior-lateral part of high-level auditory areas. This activation pattern was strikingly similar to the pattern found in hearing subjects performing the auditory version of the task. Although performing the visual task in deaf subjects induced an increase in functional connectivity between the auditory cortex and the dorsal visual cortex, no such effect was found in hearing subjects. We conclude that in deaf humans the high-level auditory cortex switches its input modality from sound to vision but preserves its task-specific activation pattern independent of input modality. Task-specific reorganization thus might be a general principle that guides cortical plasticity in the brain.

A complete equation of state for polyethylene based on Helmholtz free energy

Polyethylene (PE) is an important kind of plastic, which plays a significant role as the shell material of the fuel capsule, light weight structural element subjected to intense mechanical impact and explosion load. And it is well accepted that semi-empirical three-term equation of state (EOS) is one of the most widely used EOSs in practical work. Therefore, studies of semi-empirical three-term EOS of PE are significant for accurately predicting and analyzing the physical processes and experimental results under high pressure compression. A semi-empirical three-term complete EOS of PE based on the model of Helmholtz free energy is established in this work. According to the EOS model, the Helmholtz free energy is composed of cold energy, thermal contribution of atoms and thermal excitation of electrons. The cold energy is calculated by using the Mie potential. The optical frequency branch of atomic vibration and the thermal contribution of electrons are neglected in the calculation at temperatures below 104 K. The parameters of Helmholtz free energy are calculated by using the shock Hugoniot data and thermal parameters at ambient state. And then, the application pressure range and reliability of the semi-empirical three-term EOS of PE are evaluated. Shock Hugoniot, shock wave temperature and Grneisen coefficient of PE are deduced from the EOS. The results show that shock Hugoniot and shock wave temperature are consistent well with the experimental data and the first-principle calculation in a pressure range of 150 GPa. Because the specific volume of PE does not change obviously in the melting and chain dissociation process, the assumption of linear Hugoniot relation of PE is valid for calculating the cold energy parameters. The calculation results deviate from the experimental results at about 150 GPa while the compression lasts up to the chemical bond dissociation pressure of PE. In addition, the value of buck modulus and its derivative with respect to pressure at zero pressure and temperature depend strongly on Hugoniot parameters. Therefore, the parameter of Helmholtz free energy in this work is only valid for compression. In conclusion, the Helmholtz free energy model and parameters can well reproduce the experimental data and reasonably describe the thermodynamic state of PE at its dissociation pressure. Moreover, it should be pointed out that a more refined model of phase transition and thermal contribution of atoms and electrons should be considered when extrapolated to higher pressure.

Peanut-Like Crystals in Polycarbonate/Plasticizer Blends

Bisphenol-A polycarbonate (BAPC) crystal with unusual morphology is obtained in the solution-cast films of BAPC/plasticizer blends. It seems like Siamese twin spherulites, and owns a peanut-like morphology with more than one nucleating sites. Furthermore, concentric black dotted rings, which should be the aggregation regions of plasticizers, are also observed within the peanut-like crystals. The peanut-like morphology has no selectivity to the kinds of plasticizer and the casting temperature. The development of these peanut-like crystals is mainly ascribed to the local orientations of BAPC chains, which are induced by the concentration fluctuation during solvent evaporation and further fixed by the quick drying process. The concentric black dotted rings within the peanut-like crystals shall be attributed to the driving effect of BAPC crystalline lamellae and phase separation between plasticizers and BAPC. This work opens a new window for the regular arrangement of small molecules.

PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE NUMBERED HEADS TOGETHER UNTUK MENINGKATKAN AKTIVITAS BELAJAR MATERI POLIMER SISWA KELAS XII IPA SMAN 2 PONTIANAK

This research has been conducted to figure out the improvement of the students learning activities in polymer lesson at twelft grade of science program in SMAN 2 Pontianak by the application of cooperative learning model type numbered heads together. The form of this research is Classroom Action Research. The research was conducted in three cycles. The students learn about the meaning and the reaction how the polymer is formed, the classification of polymer, kinds of plastic, the use and the impact of polymer as well. The instrument used is observation of the students’ activities and questioners. Based on the data analysis, it can be concluded that there is improvement on the students learning activities. The percentage of the students activities is 29,03% in the first cycle, 43,75% in the second cycle and 84,38% in the third cycle. It is recommended for the teachers to choose cooperative learning model type numbered heads together to become one of the learning model alternative in polymer lesson to improve the students’ learning activities. Keywords : Cooperative learning, numbered heads together.

Catalytic and thermal depolymerization of low value post-consumer high density polyethylene plastic

The feasibility of catalytic and non-catalytic pyrolytic conversion of low value post-consumer high density polyethylene (HPDE) plastic into crude oil and subsequent distillation was explored. Translation of optimized conditions for catalytic and non-catalytic pyrolysis from TGA to a bench-scale system was validated using another kind of plastic (HDPE). The properties of the plastic crude (PC) oil and residue were studied for boiling point distribution; molecular weight distribution; elemental composition; and thermal degradation. The plastic crude oils had properties similar to conventional crude oil. The resulting PC oils were distilled into motor gasoline, diesel #1, diesel #2, and vacuum gas oil fractions. An increase in gasoline and diesel-range fractions was observed with Y-zeolite and MgCO3 catalysts, respectively. Diesel and vacuum gas oil fractions were the major products in the absence of catalyst. The distillate fraction was characterized for fuel properties, elemental composition, boiling point, and molecular weight distribution. The fuel properties of the diesel-range distillate (diesel fraction) were comparable to those of ultra-low sulfur diesel (ULSD) fuel. Market demand, growth, and value of end products will dictate which process, non-catalytic or catalytic (Y-Zeolite/MgCO3), is best suited for providing the product portfolio for a particular scenario.

Fear Memory.

Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.

Design and Control of Reactive Distillation Process for the Production of Methyl Valerate

Methyl valerate (VAME), also known as methyl pentanoate, is a methyl ester of pentanoic acid (valeric acid). VAME is usually used as a fragrance in the production of beauty care, soap, and laundry detergents. High purity VAME can also be used as a kind of plasticizer. This study presents design details of the process for the manufacture of VAME. A reactive distillation column (RDC) is used in the production process to overcome equilibrium limitation of the esterification reaction. There is no bottom outlet of this RDC. Both products, VAME and water, are withdrawn from the distillate of RDC and then can be separated by two strippers and a decanter. A thermally coupled design is then developed to reduce the remixing effect in the rectifying section of the RDC. The simulation results show that 30% energy saving can be achieved by using the proposed thermally coupled configuration, but only 17% of total annual costs can be saved due to the use of a compressor. Control strategies of both conventional and therm...

MENINGKATKAN HASIL BELAJAR MATERI POLIMER MELALUI PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE NUMBERED HEADS TOGETHER PADA SISWA KELAS XII IPA SMAN 2 PONTIANAK

This research has been conducted to recognize the improvement of the students study achievement in polymer lesson at 12th grade of science program in SMAN 2 Pontianak by the application of cooperative learning model type numbered heads together. The form of this research is Classroom Action Research. The research was conducted in three cycles. The students learn about the meaning and the reaction how the polymer is formed, the classification of polymer, kinds of plastic, the use and the impact of polymer as well. The instruments used are the students’ test achievement and questioners. Result of this research on the first cycle the percentage of the study completeness is 70,97%, the second cycle is 75% and the third cycle is 84,38%. It can be concluded that there is improvement on the students study result. It is recommended for the teachers to choose cooperative learning model type numbered heads together become one of the learning model alternative in polymer lesson to improve of the students’ study result. Keywords: Numbered heads together, polymer.

폐플라스틱의 열분해 시 열중량 분석 및 동역학 연구

Waste plastic differs in its speed of combustion owing to its variety in composition as well as kinds of plastic. This study is aimed at examining the thermal weight analysis and determination of its kinetics in order to derive the design element in pyrolysis of RPF (Refused Plastic Fuel) as the plastic solid fuel. Based on the result of TGA (Thermogravimetric analysis), kinetic characteristics were analyzed by using Kissinger method which are the most common method for obtaining activation energy, and experimental conditions of TGA were set as follows: in a nitrogen atmosphere, gas flow rate of 20 ml/min, heating rate of , and maximum hottest temperature of . The method used for determining the property of waste plastic when thermally decomposed was thought feasible as the basic data in deciding the performance, design, and optimal operating condition of the reactor in the actual reactor.

The composition and ageing of high‐viscosity and elasticity asphalts

Different kinds of plasticizers and crosslinkers were used to prepare high‐viscosity modified (HVM) asphalt and high‐elastic modified (HEM) asphalt and the major physical properties were studied and compared. The kinds of plasticizers were optimized and the difference in composition between HVM and HEM asphalts was clarified. The plasticizers with different thickness and flexibility were available for HVM or HEM asphalts respectively. The kinds of crosslinkers were also compared and optimized and it was found that the most effective crosslinker was sulfur. The effect of anti‐ageing reagent on HEM asphalt was confirmed and it was found that one of the most effective way to retain the properties of HVM and HEM asphalt before ageing was to increase the SBS content further. POLYM. COMPOS., 38:2509–2517, 2017. © 2015 Society of Plastics Engineers

Flexible nanoscale thread of MnSn(OH)6 crystallite with liquid-like behavior and its application in nanocomposites.

We reported a solvent-free nanofluid based on MnSn(OH)6 crystallite with thread-like morphology through sulfuric-acid-terminated organosilanes as corona and polyether amine as canopy. The resultant is characterized by various analytical techniques and shows excellent solubility, good dispersity, improved processability and fluidity at room temperature in the absence of any solvents, which offer great potential in applications such as plasticizers with effects of toughening and reinforcement in nanocomposites. In addition, as a kind of plasticizer, it can also improve the Tg of its nanocomposites. These advantages of the flexible nanoscale thread of MnSn(OH)6 crystallite make it can be easily applied on the fabrication of high performance of nanocomposites.