bluuebunny/crossref_metadata_2025 huggingface dataset:
Biogenic Synthesis of AgNPs with Saussurea lappa C.B. Clarke and Studies on Their Biochemical Properties
Authors: Riaz Muhammad , Altaf Muhammad , Faisal Amir , Shekheli Muhammad Azhar , Miana Ghulam Abbass , Khan Muhammad Qayyum , Shah Muhammad Ali , Ilyas Syed Zafar , Khan Ayaz Arif
Published: September 2018

Nanotechnology has become an irreplaceable need and green synthesis of nanoparticles offers several advantages over physical and chemical methods. Medicinal plants are the main reservoirs of drugs and drug candidates. We report the biogenic synthesis of silver nanoparticles (AgNPs)
using aqueous root extract of Saussurea lappa. Verification and characterization of these nanoparticles were done by UV-visible spectroscopy, XRD-analysis and Scanning Electron Microscopy and FT-IR. Extract-loaded-AgNPs showed the highest inhibition zone against Escherichia coli
(11.0 mm) and intermediate against Pseudomonas aeruginosa (9.0 mm). The methanolic root extract of S. lappa alone, also moderately inhibited Pseudomonas aeruginosa (9.0 mm) and showed lower activity (6.0 mm) against Escherichia coli. Its aqueous roots extract inhibited
(6.0 mm) the growth of tested organisms. Methanolic extract showed antioxidant potency (IC50 = 0.814 μg/mL). Experiments revealed the presence of phenols and flavonoids in the roots of Saussurea lappa. These findings provide promising interest to exploit Saussurea
lappa for the biogenic synthesis of AgNPs and their biological applications.
On the Constitution of Typhoons
Authors: Gherzi E.
Published: September 2018

The question of frontology and modern synoptic analysis of tropical cyclones has come to the fore rapidly in the last decade owing to the influence of the Norwegian School and the improvement in collecting synoptic information in the tropics; Fr. Gherzi has been a cogent critic of typhoon frontology ever since the Indian and Japanese meteorologists first put fronts on typhoon maps. He has already expressed some of his views on the question in Gerlands Beitr., bd. 29, p. 344, Q. Jn. R. Met. Soc., 1932, p. 303, Met. Zts., March 1937, and in “Typhoons in 1933”, Zikawei, 1934 ; and is an authority on the subject with years of study and forecasting experience in the Far Eastern region. While many meteorologists will agree with some of his criticisms, in regard to Fr. Deppermann's work we think he may have misread him as the latter in his texts specifically denies that the fronts always extend right into the center of the typhoon even though his maps seem to show them that way, and also he does not claim the fronts in themselves are dynamically necessary for a typhoon; Deppermann does, however, seem to believe that as far as the Philippine region is concerned the typhoons do not form totally within a single homogeneous air mass and that the greater convergence in the SW Monsoon sector is somehow an important dynamic factor. It is with these points that Gherzi is really in disagreement. One of Deppermann's maps is reproduced here in order that the reader may see what is referred to, and in a coming issue of the Bulletin some of Fr. Deppermann's views will be quoted by way of rebuttal.—R. G .S.
Ozonesonde Quality Assurance: The JOSIE–SHADOZ (2017) Experience
Authors: Thompson Anne M. , Smit Herman G. J. , Witte Jacquelyn C. , Stauffer Ryan M. , Johnson Bryan J. , Morris Gary , von der Gathen Peter , Van Malderen Roeland , Davies Jonathan , Piters Ankie , Allaart Marc , Posny Françoise , Kivi Rigel , Cullis Patrick , Hoang Anh Nguyen Thi , Corrales Ernesto , Machinini Tshidi , da Silva Francisco R. , Paiman George , Thiong’o Kennedy , Zainal Zamuna , Brothers George B. , Wolff Katherine R. , Nakano Tatsumi , Stübi Rene , Romanens Gonzague , Coetzee Gert J. R. , Diaz Jorge A. , Mitro Sukarni , Mohamad Maznorizan , Ogino Shin-Ya
Published: September 2018

The ozonesonde is a small balloon-borne instrument that is attached to a standard radiosonde to measure profiles of ozone from the surface to 35 km with ∼100-m vertical resolution. Ozonesonde data constitute a mainstay of satellite calibration and are used for climatologies and analysis of trends, especially in the lower stratosphere where satellites are most uncertain. The electrochemical concentration cell (ECC) ozonesonde has been deployed at ∼100 stations worldwide since the 1960s, with changes over time in manufacture and procedures, including details of the cell chemical solution and data processing. As a consequence, there are biases among different stations and discontinuities in profile time series from individual site records. For 22 years the Jülich (Germany) Ozonesonde Intercomparison Experiment (JOSIE) has periodically tested ozonesondes in a simulation chamber designated the World Calibration Centre for Ozonesondes (WCCOS) by WMO. During October–November 2017 a JOSIE campaign evaluated the sondes and procedures used in Southern Hemisphere Additional Ozonesondes (SHADOZ), a 14-station sonde network operating in the tropics and subtropics. A distinctive feature of the 2017 JOSIE was that the tests were conducted by operators from eight SHADOZ stations. Experimental protocols for the SHADOZ sonde configurations, which represent most of those in use today, are described, along with preliminary results. SHADOZ stations that follow WMO-recommended protocols record total ozone within 3% of the JOSIE reference instrument. These results and prior JOSIEs demonstrate that regular testing is essential to maintain best practices in ozonesonde operations and to ensure high-quality data for the satellite and ozone assessment communities.
A Comprehensive Observational Study of Graupel and Hail Terminal Velocity, Mass Flux, and Kinetic Energy
Authors: Heymsfield Andrew , Szakáll Miklós , Jost Alexander , Giammanco Ian , Wright Robert
Published: September 2018

This study uses novel approaches to estimate the fall characteristics of hail, covering a size range from about 0.5 to 7 cm, and the drag coefficients of lump and conical graupel. Three-dimensional (3D) volume scans of 60 hailstones of sizes from 2.5 to 6.7 cm were printed in three dimensions using acrylonitrile butadiene styrene (ABS) plastic, and their terminal velocities were measured in the Mainz, Germany, vertical wind tunnel. To simulate lump graupel, 40 of the hailstones were printed with maximum dimensions of about 0.2, 0.3, and 0.5 cm, and their terminal velocities were measured. Conical graupel, whose three dimensions (maximum dimension 0.1–1 cm) were estimated from an analytical representation and printed, and the terminal velocities of seven groups of particles were measured in the tunnel. From these experiments, with printed particle densities from 0.2 to 0.9 g cm−3, together with earlier observations, relationships between the drag coefficient and the Reynolds number and between the Reynolds number and the Best number were derived for a wide range of particle sizes and heights (pressures) in the atmosphere. This information, together with the combined total of more than 2800 hailstones for which the mass and the cross-sectional area were measured, has been used to develop size-dependent relationships for the terminal velocity, the mass flux, and the kinetic energy of realistic hailstones.
Investigation of Sand Ripple Dynamics with Combined Particle Image and Tracking Velocimetry
Authors: Frank-Gilchrist Donya P. , Penko Allison , Calantoni Joseph
Published: September 2018

Accurately assessing the response of sediments to oscillatory flows requires high-resolution fluid velocity and sediment transport measurements at the fluid–sediment interface. Fluid and sediment grain velocities were measured simultaneously with combined particle image and tracking velocimetry under oscillatory flows over movable sand ripples. Three high-speed cameras equipped with varying optical filters were used to distinguish between fluorescent fluid tracers and the grains, from which the fluid and grain velocities were determined, respectively. Individual grains were tracked during transport to determine velocities and trajectories. Sediment grains were first mobilized by a vortex impacting the bed during flow reversal and suspended into the water column just prior to vortex ejection from the ripple crest, similar to previous observations. During phases of maximum flow velocity, additional grains were mobilized by the shear stress and were subsequently suspended. The flow reversed and similar observations were made in the opposite direction. Consequently, four peaks in suspended sediment concentration were observed throughout the flow cycle, consistent with previous observations. However, some previous researchers attributed peaks in suspended sediment concentration occurring during phases of maximum flow velocity to sediment-laden vortices that were shed from adjacent ripples. The measured sediment grain velocities were of similar magnitude and phase to the near-bed fluid velocities when the grains were being advected with the flow. Measurements of suspended sediment concentration agreed well with semiempirical formulations having an average root-mean-square deviation of approximately 4 × 10−5m3m−3. Predictions of settling velocity also compared well with the laboratory estimates, agreeing to within 90%.
Can the Direct Effect of Aerosols Improve Subseasonal Predictability?
Authors: Benedetti Angela , Vitart Frédéric
Published: September 2018

The fact that aerosols are important players in Earth’s radiation balance is well accepted by the scientific community. Several studies have shown the importance of characterizing aerosols in order to constrain surface radiative fluxes and temperature in climate runs. In numerical weather prediction, however, there has not been definite proof that interactive aerosol schemes are needed to improve the forecast. Climatologies are instead used that allow for computational efficiency and reasonable accuracy. At the monthly to subseasonal range, it is still worth investigating whether aerosol variability could afford some predictability, considering that it is likely that persisting aerosol biases might manifest themselves more over time scales of weeks to months and create a nonnegligible forcing. This paper explores this hypothesis using the ECMWF’s Ensemble Prediction System for subseasonal prediction with interactive prognostic aerosols. Four experiments are conducted with the aim of comparing the monthly prediction by the default system, which uses aerosol climatologies, with the prediction using radiatively interactive aerosols. Only the direct aerosol effect is considered. Twelve years of reforecasts with 50 ensemble members are analyzed on the monthly scale. Results indicate that the interactive aerosols have the capability of improving the subseasonal prediction at the monthly scales for the spring/summer season. It is hypothesized that this is due to the aerosol variability connected to the different phases of the Madden–Julian oscillation, particularly that of dust and carbonaceous aerosols. The degree of improvement depends crucially on the aerosol initialization. More work is required to fully assess the potential of interactive aerosols to increase predictability at the subseasonal scales.
Effect of Nasal Valve Shape on Downstream Volume, Airflow, and Pressure Drop: Importance of the Nasal Valve Revisited
Authors: Naughton John P. , Lee Andrew Y. , Ramos Eric , Wootton David , Stupak Howard D.
Published: September 2018

Objectives:

The relative importance of the nasal valve relative to the remainder of the nasal airway remains unknown. The goal of this article was to objectively measure the shape of the nasal inlet and its effect on downstream airflow and nasal cavity volume using a physical model and a physiologic flow model.

Methods:

A patient who had isolated nasal valve surgery and had pre- and postoperative computed tomography scans available for analysis was studied. Nasal inlet shape measurements, computational fluid dynamics, and nasal volume analysis were performed using the computed tomography data. In addition, a physical model was used to determine the effect of nasal obstruction on downstream soft tissue.

Results:

The postoperative shape of the nasal inlet was improved in terms of length and degree of tortuosity. Whereas the operated-on region at the nasal inlet showed an only 25% increase in cross-sectional area postoperatively, downstream nonoperated sites in the nasal cavity revealed increases in area ranging from 33% to 51%. Computational fluid dynamics analysis showed that airway resistance decreased by 42%, and pressure drop was reduced by 43%. Intraluminal mucosal expansion was found with nasal obstruction in the physical model.

Conclusion:

By decreasing the degree of bending and length at the nasal valve, inspiratory downstream nonoperated sites of the nasal cavity showed improvement in volume and airflow, suggesting that the nasal valve could play an oversized role in modulating the aerodynamics of the airway. This was confirmed with the physical model of nasal obstruction on downstream mucosa.
The Relationship between Conversion Factors and Health: Evidence from the Ready-Made Garment Workers in Bangladesh
Authors: Nasrin Shamima , Rasiah Rajah , Baskaran Angathevar , Khan Hafiz TA
Published: September 2018

This study examined the association between health condition and conversion factors (i.e. environmental, individual and social) among workers in the ready-made garment (RMG) industry in Bangladesh. It used data gathered from a cross-sectional survey of 775 RMG workers in the Dhaka and Narayanganj districts. Using multiple logistic regression, the study found that: (1) achieving good health among RMG workers is hindered by various factors including high job-related demands, high noise levels, workplace crowding, heavy workloads, and low level of educational attainment; (2) job-related rewards and marital status have contributed to achieving good health; (3) health condition of workers is worse for women than for men; and (4) poor health condition is more prevalent among the oldest age group than in the lowest age category. The main contributions of this research: (1) this study develops a comprehensive framework to determine the factors affecting the health condition of manufacturing workers in general, and RMG workers in particular; and (2) it also examines the effects of both psychosocial and physical working conditions on the health of RMG workers.
“It’s Just the Way I Learn!”: Inclusion from the Perspective of a Student with Visual Impairment
Authors: Gilbert Danni
Published: September 2018

This article describes the inclusive experience of a student with visual impairment in secondary band settings. Information obtained from students with visual impairments who have experienced active participation in school music ensembles may provide much-needed insight into instructional strategies that could improve inclusion. Many music educators believe they lack adequate resources and training in including students with visual impairments. Therefore, a deeper understanding of the experience of participating in secondary performing ensembles from the viewpoints of students can help guide the efforts of those involved in their music education.
How Positive Festival Results Impact a Music Program
Authors: Pope David A. , Mick James P.
Published: September 2018

Adjudicated festival ratings can affect developing musicians, ensemble directors, and music programs long after festival performances end. With prior research demonstrating that adjudicators provide an abundance of positive ratings at festivals, this article discusses how ratings—both appropriate and inappropriate—may influence students’ musical development and the growth of music programs, as well as ensemble directors’ professional development. Based on their personal teaching philosophies and the discussion points in this article, directors are encouraged to determine whether their current adjudicated festivals stimulate or obstruct the development of their students, their music programs, and themselves.
Stop Pushing Me Away: Relative Level of Facebook Addiction Is Associated With Implicit Approach Motivation for Facebook Stimuli
Authors: Juergensen James , Leckfor Christina
Published: September 2018

The use of Facebook and other social media sites has increased to the point that some consider it to be a behavioral addiction. Previously, research has used the Approach–Avoidance Task to measure implicit approach and withdrawal tendencies in response to a variety of stimuli, including alcohol, desserts, cigarettes, spiders, and cannabis. When responding to these types of stimuli, individuals typically evidence an approach bias toward appetitive images and a withdrawal bias in response to undesirable and/or fearful stimuli. The present study was designed to test the validity of an adapted version of the Approach–Avoidance Task by investigating how self-reported Facebook addiction tendencies, measured via the Bergen Facebook Addiction Scale, predicted automatic approach tendencies toward Facebook-related stimuli using the Facebook-Approach–Avoidance Task. Participants with higher self-reported tendencies of Facebook addiction tended to approach Facebook-related stimuli faster. The present study is the first to indicate a relationship between self-reported Facebook addiction tendencies and implicit approach motivation using a behavioral measure. This finding provides initial support for the use of the Facebook-Approach–Avoidance Task as a measure of Facebook addiction, and further validation could lead to the development of additional assessment and training paradigms in the future.
Socialist Workhorse to Capitalist Powerhouse: Developing a Modern Chinese Commercial Fleet in the Pre-Reform Era
Authors: McMillan Gregor
Published: September 2018

As China approaches dominance in commercial shipping, the task of understanding its rise from irrelevance as a seafaring nation in 1949 to its current position has increasing importance. This article remedies the absence of scholarship on this subject by describing the foundation and development of China’s commercial fleet through political turmoil before 1971. Working with data from Chinese annals 志, chronicles 史, and international primary sources, the article explores the development of China’s merchant fleet. Fleet development followed two contrasting modes: the domestic fleet, founded on a backward junk fleet and a limited fleet of liners inherited in 1949 and shaped by internal pressures, and an international fleet, which developed modern capacity and became integrated with the global market. The article traces the growth of China’s fleet through a period of political turmoil from 1966 to 1971 when, paradoxically, fleet-building demonstrated impressive stability. This suggests high-level political patronage despite violent and contrary changes in political circumstances.
Power, labour power and productive force in Foucault’s reading of Capital
Authors: Feldman Alex J.
Published: September 2018

This article uses Foucault’s lecture courses to illuminate his reading of Marx’s Capital in Discipline and Punish. Foucault finds in Marx’s account of cooperation a precedent for his own approach to power. In turn, Foucault helps us rethink the concepts of productive force and labour power in Marx. Foucault is shown to be particularly interested in one of Marx’s major themes in Capital, parts III–IV: the subsumption of labour under capital. In Discipline and Punish and The Punitive Society, Foucault offers a genealogy of the forms of labour power ( Arbeitskraft) and productive force ( Produktivkraft). One of his central problems is to understand how labour power is converted in productive force and how, prior to that, productive subjects who can properly bear and dispose of their labour power are formed. Foucault’s reading of Capital resonates with those currents of Marx interpretation today that seek to repoliticize the concept of productive force and to offer a materialist account of subject formation.
Change over Time in the Thermal Conductivity of Ten-Year-Old PUR Rigid Foam Boards with Diffusion-Open Facings
Authors: Albrecht W.
Published: September 2018

To estimate the long-term change in thermal conductivity of PUR rigid foam, various accelerated ageing processes (e.g. 70 °C ageing procedure) are used. Results of ageing processes are safety increments to cover a lifetime in practice of between 25 and 50 years.

To compare estimated increments with the change over time in thermal conductivity of real boards, a research project was started. The research project was sponsored by the German Polyurethane Producers’ Association (IVPU) and funds of the German Minister of Economics over the AIF (Association of Industrial Research Institutes).

The tables and diagrams show the thermal conductivity of PUR boards in full thickness and the cell gas composition over a period of ten years.

The shape of the curves and the measured values are compared with the typical diffusion coefficients and thermal conductivity of cell gases.

The development of the curves shows that the fixed increments in the European PUR standard EN 13165, 2001–10 for pentane blown PUR foams are correctly calculated. These fixed increments provide assurance for the users of PUR rigid foam boards over very long periods (e.g. 25 years) and give confidence to the builders and the building supervisory authorities.
Extrusion of Microcellular Foams Using Pre-Saturated Pellets and Solid-State Nucleation
Authors: Kumar Vipin , Nadella Krishna , Branch Greg , Flinn Brian
Published: September 2018

A novel process for continuous production of microcellular foams has been developed and applied to make flat microcellular strips from PVC. The first novel aspect of the process consists of the way in which the blowing agent, or gas, is delivered to the extruder. We pre-saturate the solid PVC pellets with carbon dioxide. The gas- saturated pellets are then put in the extruder hopper. The second novel aspect of the process is in applying nucleation in the solid state to continuous extrusion. As the pellets are crushed and heated in the extruder, a large number of bubbles nucleate as the temperature reaches the Tg of the CO2 plasticized PVC. The melt thus is full of nucleated bubbles that are not able to grow in size due to the pressure that develops in the barrel. When the melt exits at the die, where the pressure is atmospheric, the bubbles have a chance to grow larger and create foam. The process employs effective cooling strategies at the die exit, including lower melt temperatures, to keep the bubbles in the microcellular range.
Characterization of EVA Residues from the Shoe Industry and Post-Consumer Urban-Waste Polyethylenes
Authors: Zattera A.J. , Bianchi O. , Oliveira R.V.B. , Canto L.B. , Ferreira C.A. , Zeni M.
Published: September 2018

This paper presents a characterization of a crosslinked EVA residue (EVA-c) from expanded sheets used in the shoe industry and post-consumer urban-waste polyethylenes regarding their molecular (FTIR), mechanical (tensile and impact tests), morphological (SEM), thermal (DSC, TGA) and dynamic-mechanical (DMTA) properties. For comparison, the properties of the EVA-c and recycled polyethylenes are compared to respective virgin polymers. The recycled polyethylenes generally presented similar properties to the virgin ones. On the other hand, some EVA-c properties differed from virgin ones since it has a high degree of crosslinking and it therefore has a higher tensile modulus and lower elongation at break, notched Izod impact strength and hardness. Additionally, crosslinking was also found to modify the thermal properties (TGA and DSC) of EVA-c.
Microcellular Foams Prepared by Exposing (CO2 + H2O) Laden Polymers to Microwaves
Authors: Zhang Zhiyi , Lu Shiying , Nawaby A. Victoria , Handa Y. Paul
Published: September 2018

Polymers conditioned with compressed CO2 and H2O underwent rapid foaming when exposed to microwaves using a conventional oven. The rapidly oscillating water molecule dipoles generated enough heat to allow nucleation and growth of closed cells. Microcellular foams with cells less than 10 μm were produced from polymers such as poly(methyl methacrylate) and polycarbonate. The technique provides a fast foaming process whereby the cell morphology can be easily controlled by adjusting the microwaves intensity and flux, and exposure time.
Do Nanoparticles Really Assist in Nucleation of Fine Cells in Polyolefin Foams?
Authors: Ramesh N.S. , Lee S.T.
Published: September 2018

Nanotechnology is an enabling technology that is extremely large to cover in one technical paper. It touches various technology disciplines and covers several applications. The purpose of this paper is to investigate the effect of nanoclay on nucleation of polypropylene foams. Particularly, the goal is to understand the ability of nanocomposites in producing finer cells compared to talc in polypropylene.
Synthesis and Characterization of Porous Polyaniline Conductive Polymers
Authors: Price Aaron D. , Naguib Hani E.
Published: September 2018

Polyaniline conductive polymers exhibit great potential for linear actuator applications. Many recent studies report methods to develop polyaniline-based materials with increased mechanical properties, electrical conductivity, and faster response time during actuation. In this study, porous blends of poly(methylmethacrylate) and polyaniline are processed using a two phase batch foaming setup. The effect of materials, processing, and system parameters on the physical properties of the resulting cellular structure are investigated. Hence, the effect of density and cell morphology on the electrical conductivity is elucidated.
Compliance with compression therapy in primary chronic venous disease: Results from a tropical country
Authors: Ayala Álvaro , Guerra Jose D , Ulloa Jorge H , Kabnick Lowell
Published: September 2018

Objectives

To describe compliance rates of compression therapy in a cohort of patients with chronic venous disease and also to describe frequent causes of non-compliance.

Methods

A total of 889 patients with primary chronic venous disease were prescribed compression therapy after being evaluated by vascular surgeons. Subjects had a first visit during which time compression therapy was prescribed in addition to a follow-up visit. Strength of compression, type, prescription duration, and reasons of non-compliance were queried at follow-up.

Results

Only 31.8% of the patients reported wearing compression therapy as prescribed, 31.4% reported wearing compression most days, 28.3% reported wearing compression intermittently, and 8.5% of the patients reported not wearing compression at all. The main reasons of non-compliance were: uncomfortable (49.4%), too difficult to put on (34.5%), skin problems (itching) (21.5%), and unattractive (19.8%).

Conclusions

Compliance with compression therapy in chronic venous disease is still a subject of concern as most patients are not using compression therapy as prescribed.
Oil Bleeding Behaviour of Self-Lubricating Liquid Silicone Rubbers
Authors: Pohmer K.
Published: September 2018

The term liquid silicone rubber (LSR) covers a whole range of two-pack, heat-curing products, which may be processed using liquid injection moulding (LIM), a technique similar to thermoplastic injection moulding. Although this product group only accounts for about one thousandth of the world rubber market (corresponding to approximately 18 000 t/a) and is therefore a speciality rubber (ref. 1), due to their excellent properties, such as thermal stability, low-temperature flexibility, constantly good mechanical properties over a wide temperature range and good physiological compatibility to name but a few, products made of LSR are used in a wide variety of applications in many different fields. The most important fields of application include household appliances and the food industry, electronics and electrical engineering, sports and leisure activities and the automotive and aerospace industries (ref. 2).

As a result of their low-temperature flexibility and heat stability, silicone rubbers are used for numerous applications in the automotive sector. Examples include spark-plug socket jackets, radiator seals, exhaust mountings, O-rings, seals and membranes. Nowadays, it is standard practice to use weather packs made of special silicone rubbers to which has been added a silicone oil incompatible with rubber and which exudes slowly after the product has cured for sealing cable connectors for wiring harnesses.
A New Role for the Automotive Supplier Industry
Authors: Dudenhöeffer F.
Published: September 2018

This article summarises the most important results of the study ‘Trends in the Automobile Supplier Industry’, performed under the leadership of Prof. Dudenhöffer with the corporation of Dipl.-Betriebswirtin Carina Densing with support from the VDA (Association of German Employers)
Nanocomposites. 2. a New Flame Protection System for Polymers
Authors: Beyer G.
Published: September 2018

Nanocomposites contain only a very small amount of modified layered silicates as fillers. The flame retardant mechanism in nanocomposites is based on the extremely effective char formation during decomposition as a result of combustion. This char provides a thermal protection for the polymer, prevents further decomposition, and also delays the release of flammable gases during combustion. The cone calorimeter is the most suitable instrument for measuring these effects. Nanocomposites have significant advantages over traditional flame retardant systems such as aluminium hydroxide or magnesium hydroxide.
Injection Moulding of Silicone Rubber
Authors: Hunold D.
Published: September 2018

Describes injection moulding technology for liquid silicone rubber (LSR) and solid silicone rubber. Krauss-Maffei's extensive and modular C-series of injection moulding machines may be customised to meet the special requirements of silicone processing. Kraus-Maffei's moulding machines for processing HTV solid silicone rubber with the AZ screw conveyor have been long-established on the market and now configurations for LSR processing are also available.
Flocking of Rubber Profiles for the Automotive Industry
Authors: Wefringhaus R.
Published: September 2018

Over the past few decades, electrostatic flocking of rubber profiles has developed into an important technique which is now extensively used in the automobile industry. Flocked profiles are used on car doors, sunroofs and windows. They have two functions in cars: seals with the bodywork and the facilitation of opening and closing functions with a low degree of force.

This article provides a brief explanation of the theoretical and practical aspects (with examples).
Studies of Friction Mechanism in Silica and Carbon Black Filled SBR: (3) Friction of Carbon Black and Silica Filled SBR Blends
Authors: Amino N. , Uchiyama Y. , Iwai T. , Maeda M.
Published: September 2018

Tire tread compounds usually consist of polymer blends. In this paper the friction for immiscible SBR blends which consist of two different SBRs having different glass transition temperatures of −51 °C and −6 °C are investigated. The effects of the blend ratio of these two SBRs and the added fillers such as carbon black and silica on the friction are also investigated. The friction forces are measured when rubber specimens are rubbed against dry or wet metal gauze. The friction force-sliding speed curves for the SBR blends are related to their storage modulus E′, loss tangent tan δ, contact area A and shear strength s.

The adhesion component of the friction for each SPR blend shows a peak at the sliding speed range examined. As the blend ratio of the SBR having higher Tg of −6 °C is raised, the peak value is lowered and the peak shifts to lower sliding speed. The adhesion component of the friction for silica-filled SBR blends is higher than that of carbon black-filled SBR blends. These trends are also shown when rubber specimens are rubbed against the wet metal gauze. On the other hand, the hysteresis component of friction is raised when the blend ratio of the SBRs having higher Tg is increased.
Challenges for EPDM
Authors: Graf HJ , Yu ST , Di Agnillo L
Published: September 2018

EPDM polymers have been used in automotive weather seals for more than 30 years and there have been numerous investigations into their mixing and extrusion. However, the stability of EPDM polymers under the heat and shear forces that occur during the production of composites is generally ignored and inadequately understood. This paper describes an investigation into a variety of commercial grades of EPDM polymers exposed to heat ageing and shear. The behaviour of the polymers on their own and in composites was investigated. Weight loss and colour change were observed at 150°C in a hot air oven. Shear stability was investigated in a mixing chamber with an internal volume of 800 cm3. The mixer was equipped with tangential (Banbury) rotors. The chamber temperature was set at 66°C. The change in the molecular weight of the polymer, the molecular weight distribution and the degree of branching after exposure to shear stress for different periods of time were characterised using GPC and RPA. It was established that a polymer product with metallocene catalysts has the best thermal stability. However, a polymer with approximately the same molecular weight produced with conventional Ziegler-Natta catalysts had the best overall molecular and structural stability when exposed to heat ageing and shear. As far as the oil-extended polymers with high molecular weights were concerned, one of the polymers investigated was found to have much better molecular weight retention than the oil-extended polymer even though they are both produced with similar catalysts and production methods. It is not at present possible to reach a final conclusion regarding the interaction between the stability of a polymer when aged in hot air or in the mixer and the catalysts used in its production assuming that most polymers contain a similar stabiliser in a similar concentration.
Kinetics of the Acid-Catalysed Hydrolysis of Vinyl Acetate in the Presence of Anionic Surfactants
Authors: Karamyan D. R. , Sergeeva S. N. , Beileryan N. M. , Voskanyan P. S. , Eritsyan V. K. , Gevorkyan L. A.
Published: September 2018

Vinyl acetate (VAc) is one of the most frequently investigated and widely used monomers. Multitonnage production of different (co)polymers in the form of lacquers, dispersions, and “beads” of various grades of polyvinyl alcohol and polyvinyl acetals has been based on VAc [1]. The use of new initiating systems and other components of the reaction system can make it possible to improve or even change considerably the service properties of polymers based on vinyl acetate and, thus, to expand the area of their application. The present investigation involved the production of high molecular weight polyvinyl acetate by emulsion polymerisation of vinyl acetate in the presence of initiating systems based on chelate complexes of manganese. The application of the given systems is effective at pH ≤ 4 and therefore presupposes the use of acidic agents. Under the given conditions, vinyl acetate, as an ester, will undergo hydrolysis with the formation of acetaldehyde and acetic acid, which have a negative effect both on the polymerisation process and on the quality of the polymer obtained [2–4]. Therefore, it is of interest to investigate the process of hydrolysis of vinyl acetate in an aqueous medium with real working concentrations of the principal components of the polymerisation system with the aim of determining the possibility of reducing the effect of hydrolysis products. An investigation was made of the influence on hydrolysis of sulphuric and acetic acids in the presence of ionogenic emulsifiers.
Radiation-induced Crosslinking of Plastics for Reduction of Wear in Textile Machine Applications
Authors: Heinrich G , Dorschner H , Falk E
Published: September 2018

Plastic materials are now increasingly used in tribological systems, as their specific properties may be utilised to increase the lifetime and reliability of all system elements. This paper addresses the reduction of wear as the result of the radiation-induced crosslinking of plastics. As a typical example of sliding wear, studies were performed to determine the wear on radiation-crosslinked ultrahigh molecular weight polyethylene used in textile machines and the limitations of this modified material determined. The specific objective was the development of appropriate thermoplastics for use as counterparts to steel components in the traversing unit in a winding machine with the aim of increasing its lifetime. High wear resistance on the surface, low moisture absorption under changing ambient conditions plus high impact strength were found to be the fundamental properties for the fulfilment of the specific demands for this application. To summarise, it is established that radiation-induced crosslinking leads to a significant increase in surface strength, thermal resistance and, consequently, wear resistance in the application in question.
Improving Cut/Chip/Chunk Resistance in Truck Tyres by the Use of Para-Amid Chopped Fibres
Authors: Datta R.N.
Published: September 2018

The tyre industry is continually striving to improve the cut/chip/chunk resistance of tyre treads while simultaneously maintaining a high level of product quality and product performance. Several approaches have been explored in which the fillers are varied, the cure package is optimised or polymers and their blend ratios are changed, but although each approach provides improvements with regard to cut/chip/chunk resistance, this is at the expense of hysteresis, heat buildup and fatigue properties. With its complete portfolio of aramid fibres, p-aramid (Twaron and Technora) and m-aramid (Teijin Conex), the company Teijin Twaron is the world leader in the field of chopped fibre rubber reinforcement. These chopped fibres provide rubber compounders with a potent tool for expanding the performance of rubber products beyond their current horizons
Change in the Parameters of Inhibited Oxidation of Polyethylene in the Phase Transition Region
Authors: Shlyapnikov Yu.A. , Kolesnikova N.N.
Published: September 2018

An investigation was made of the change in the parameters of oxidation of polyethylene (PE) in the presence of a phenolic antioxidant in the temperature range 80–210°C. In the region of the melting point of polyethylene, about 108°C, inflections occur on the curves of the dependence of a number of oxidation parameters. A considerable difference was found in the properties of an entirely molten polymeric substance and an amorphous substance of the same composition but kept below melting point.
Aromatic Polysulphones
Authors: Khasbulatova Z.S.
Published: September 2018

A review is given of the work of domestic and foreign scientists in the period from 1989 to 2005 on methods of synthesis of polymers of this class.
Oligomeric Siloxane-containing Polyphenols and their Reactions with Phenyl Glycidyl Ether
Authors: Simakina E.A. , Kopylov V.M. , Kovyozin V.A. , Sokol'skaya I.B. , Kireev V.V. , Kurtova S.A. , Raigorodskii I.M.
Published: September 2018

29Si, 1H, and 13C NMR spectroscopic analyses were conducted to investigate the interaction of oligomeric siloxane-containing polyolefins and phenyl glycidyl ether. The kinematic viscosity was determined using an Ubellohde viscometer.
Influence of the Thermodynamic State of Bisphenol a and Aliphatic Epoxy Oligomers on the Temperature Dependences of Newtonian Viscosity
Authors: Kolesnikova E.F. , Babaevskii P.G. , Zhavoronok E.S. , Chalykh A.E.
Published: September 2018

A generalised analysis is made of experimental and published data on the temperature dependences of the Newtonian viscosity of bisphenol A and aliphatic oligomers of different molecular weight in a wide temperature range, with account taken of the departure of the experimental temperature from the hypothetical (calculated) crystallisation temperature Tcr. It is shown that the deviation of the temperature dependence of the Newtonian viscosity of epoxy oligomers from the theoretically expected dependence in accordance with activation theory and free volume theory is greater the lower the temperature range of the experiment by comparison with Tcr, and accordingly the greater the probability of formation of solid-like molecular associates or clusters. The use of Tcr as a parameter of the corresponding state (the temperature of reduction) makes it possible to plot a “universal” generalised curve of viscosity for epoxy oligomers with account taken of the dependence of their Newtonian viscosity on molecular weight.
Dependence of the Properties of Polypropylene/Ethylene–propylene Rubber Blends on the Composition of the Composite and the Characteristics of the Polymers
Authors: Novokshonov V.V. , Musin I.N. , Kimel'blat V.I.
Published: September 2018

Empirical models reflecting the dependence of the elastic strength properties of PP/EPR blends on the characteristics of the initial polymers are obtained. The characteristics of the initial polymers that ensure synergism of the elastic strength properties are determined.
Effect of Highly Dispersed Molybdenum Disulphide on the Structure and Properties of Certain Crystallising Polyolefins
Authors: Gordienko V.P. , Podlesnyi R.V. , Kasperskii A.V.
Published: September 2018

The structure and mechanical properties of high-density polyethylene filled with molybdenum disulphide (MoS2) were studied.
Influence of the Composition of Composites with Binary Filling on the Physicomechanical Properties of Polymer Films
Authors: Gorskii V.A. , Uspenskaya M.V. , Sirotinkin N.V.
Published: September 2018

The effect of fillers – aluminosilicate glass spheres and fullerene C60 – on the deformation and strength characteristics of polymer films based on crosslinked sodium polyacrylate is examined. The effect of fullerene on the absorption properties of the polymeric material is shown.
Effect of an External Electric Field on the Molecular Characteristics of ABS Plastic
Authors: Lukashevich M.F. , Orobei I.O.
Published: September 2018

The aim was to investigate the effect of a variable electric field on the concentration of residual monomers of acrylonitrile and styrene in sheets manufactured from Magnum 3404 ABS plastic (Dow).
Synthesis and Properties of Poly(Arylene Ether Sulphone-stat-arylene Sulphide Sulphone) Copolymers
Authors: Gorbatkina Yu.A. , Ivanova-Mumzhieva V.G. , Lovkov S.S. , Urman Ya.G. , Chebotarev V.P.
Published: September 2018

By the polycondensation of 4,4′-dichlorodiphenylsulphone and 4,4′-dioxydiphenyl-2,2-propane with sodium sulphide, copolymers of the poly(arylene ether sulphone-stat-arylene sulphide sulphone) series were synthesised. It was shown that synthesis can be carried out by a procedure similar to the production of polysulphones by simple replacement of part of the bisphenol component with sodium sulphide with a reactant charge in the range 1–90 mol%. It was established that the copolymers obtained, besides high physicomechanical properties, possess reduced flammability and high adhesion properties.
Comparative Assessment of the Molecular Weight of Oligooxypropylenetriol Glycidyl Ethers by Proton Magnetic Resonance and Gel Permeation Chromatography
Authors: Zhavoronok E.S. , Panov A.V. , Chalykh A.E. , Kolesnikova E.F.
Published: September 2018

PMR spectroscopy and gel permeation chromatography were used to investigate multifunctional epoxy oligomers of different molecular weight.
Study of the Process of Impregnation of Basalt Fibre Filler by Phenol–formaldehyde Binder
Authors: Simonov-Emel'yanov I.D. , Shembel N.L. , Trofimov A.N. , Surikov P.V. , Kuklin A.S.
Published: September 2018

The optimum parameters of impregnation of reinforcing basalt fibre filler by phenol–formaldehyde resins of grades BZh-3, LBS-20, and SFZh-302, and also by binders modified with epoxy resin ED-20, have been determined.
Study of Radiation Chemical Crosslinking of an Ethylene–vinyl Acetate Copolymer Filled with Aluminium Trihydrate
Authors: Sukhinina A.V. , Osipchik V.S.
Published: September 2018

The task of the present work is to investigate the effect of the radiation dose on the effectiveness of crosslinking and the structure of an ethylene–vinyl acetate copolymer filled with aluminium trihydrate. The effectiveness of radiation chemical crosslinking of a highly filled ethylene-vinyl acetate copolymer by comparison with an unfilled copolymer was established, which is confirmed by the results of investigating the kinetics of swelling and thermal deformation, and by gel fraction analysis.
Immobilisation of an Antituberculosis drug on a Polyurethane Carrier and the Study of its Properties
Authors: Galatenko N.A. , Zbanatskaya N.L. , Gritsenko V.P. , Zakashun T.E.
Published: September 2018

The structure, strength properties, and dynamics of release of the drug on polymer carriers were investigated.
Study of the Effect of Shock-wave Treatment on the Structure and Properties of Phenylone
Authors: Adamenko N.A. , Nguen N.Kh. , Fetisov A.V.
Published: September 2018

The results are given of an investigation of the effect of explosive pressing on the structure and properties of Phenylone S3. The optimum pressure of explosive pressing and the optimum temperature of subsequent sintering of preforms of 3–10 mm thickness were determined. The thermomechanical properties and the structural changes of Phenylone were investigated after shock-wave and heat treatments. The physicomechanical properties of Phenylone S3 after explosive pressing are compared with those of Phenylone S2 produced by hot pressing.
Effect of Electrothermopolarisation on the Strength Properties of Polyolefins Modified with Additions of Low-molecular-weight Dyes
Authors: Ramazanov M.A. , Guseinova A.S.
Published: September 2018

A study was made of the effect of electrothermopolarisation on the mechanical and electric strengths of polypropylene and polyethylene modified with additions of low-molecular-weight dyes. It was shown that, with increase in the strength of the polarisation electric field Ep, the mechanical and electric strengths of the polyolefins modified with additions of low-molecular-weight dyes increase, but with further increase in Ep they decrease.
The Development of Energy-dissipating Materials Based on Segmented Polyurethanes with a Microgranular Filler
Authors: Volkova E.R. , Tereshatov V.V. , Makarova M.A. , Lamzina I.S.
Published: September 2018

Polyurethane composite materials with a microgranular filler that can be processed by moulding technology comprise a promising class of materials that can effectively absorb the energy of shock and detonation waves.
The Modification of Radiation-crosslinked Composites Based on High-density Polyethylene and Ternary Ethylene–propylene Rubber with AP-U Alkylresorcinol Resin
Authors: Chagaev S.V. , Musin I.N. , Kimel'blat V.I.
Published: September 2018

An investigation was made of the modifying effect of alkylresorcinol resin on filled radiation-crosslinked composites based on high-density polyethylene. The limits of action of the modifier and also the optimum radiation doses ensuring the most satisfactory combination of properties were determined.
Features of the Polymerisation Kinetics of Methyl Methacrylate in the Presence of Initiators of Different Structure
Authors: D'yachkov I.A. , Efimov A.L. , D'yachkov A.I.
Published: September 2018

The thermographic method was used to study the polymerisation kinetics of methyl methacrylate (MMA) at 60°C in the presence of initiators: dicyclohexylperoxy dicarbonate (CPC), azoisobutyric acid dinitrile (AIAD), benzoyl peroxide (BP), and lauryl peroxide (LP). In the region of initial conversions, the mechanism of chain growth limitation is bimolecular, and the order of the reaction with respect to the initiator is 0.5. In the region of the maximum polymerisation rate, the order of the reaction with respect to the initiator is greater than 0.5 and varies according to the initiator concentration. The mechanism of chain growth limitation at extensive conversions is monomolecular. Additional initiation occurs through degradation of the polymer, governed by the formation of stresses during polymerisation. The observed differences in the polymerisation kinetics in the MMA–CPC system are connected with the redistribution of initiator in regions with inhomogeneous concentrations of monomer and polymer.