Clean Surface Research Articles

Efficacy of Disinfectants for Monkeypox Virus Inactivation on High Touch Surface Materials in Low-Resource Settings.

Disinfection efficacy tests were conducted on surface carriers inoculated with the monkeypox virus (MPXV) by applying six disinfectant solutions (and three controls) on six surfaces common in low-resource settings: four nonporous surfaces (stainless steel, glass, plastic, and latex) and two porous surfaces (ceramic and wood). Disinfectants were wiped on carriers in triplicate, with a 1 min contact time: 0.05 and 0.5% sodium hypochlorite, 70% ethanol, two quaternary ammonium compound (QAC)-based disinfectants, and 1.4% hydrogen peroxide. MPXV was then quantified, and log10 removal values were calculated. Sodium hypochlorite (0.05 and 0.5%) and ethanol (70%) removed MPXV to below detection level, ≥ 99.97% reduction for nonporous surfaces, and ≥99.40% for wood, QAC-based disinfectants were efficacious on nonporous surfaces (≥99.97% inactivation) but had diminished efficacy on wood, a porous surface, and 1.4% H2O2 had limited efficacy across all tested surfaces. Results varied by disinfectant type and surface type. Based on our results, we recommend using 0.05% sodium hypochlorite or 70% ethanol with 1 min contact time to inactive MPXV on clean nonporous and porous surfaces. As MPXV is evolving, future research with additional disinfectants, application methods, and environmental conditions and research to understand adsorption, disinfection efficacy, and transmission risk on porous surfaces are needed to develop practical disinfection recommendations.

Environmental justice of Texas recreational water quality – The disproportionate E. coli levels and trends

The presence of pathogens is one of the leading causes of stream water quality impairment in the US. Escherichia coli (E. coli) is a fecal pathogen indicator and also signals the presence of more pathogenic microbes. Although it is reported that Black, Indigenous, and communities of color suffer more from E. coli contamination, there is a lack of investigation of the potential inequality of E. coli contamination in recreational waterbodies, particularly regarding whether this inequality persists over the long term. Using E. coli monitoring data from 1,424 stations from 2001 to 2021 in Texas, we tested the research hypotheses of racial and economic inequalities in E. coli levels and trends with quantile regression and logistic regression approaches. We found that economic disparities had a more significant relationship with E. coli contamination in Texas recreational waterbodies than racial disparities after controlling for building age, land covers, imperviousness, and precipitation. The economic disparities in E. coli contamination were more prevalent after 2010 and in extreme E. coli levels. In addition, implementing watershed protection plans could mitigate the economic disparities associated with the rising trend of E. coli levels between 2001 and 2021. Findings from this research underscore clean surface water deprivation from underserved communities and call for inclusive watershed management strategies to address the water quality injustice.

Assessing effectiveness of cleaning and disinfection of equipment and environmental surfaces in cystic fibrosis clinics using an ATP assay.

Infection control guidelines for cystic fibrosis (CF) stress cleaning of environmental surfaces and patientcare equipment in CF clinics. This multicenter study measured cleanliness of frequently touched surfaces in CF clinics using an ATP bioluminescence assay to assess the effectiveness of cleaning/disinfection and the impact of feedback. Eight surfaces were tested across 19 clinics (10 pediatric, 9 adult) over 5 rounds of testing. Rounds 1 and 2 served as uncleaned baseline, and Round 3 occurring after routine cleaning. Rounds 4 and 5 were performed after feedback provided to staff and measured after cleaning. Pass rates defined as <250 relative light units were the primary outcome. Of the 750 tests performed, 72% of surfaces passed at baseline, and 79%, 83%, and 85% of surfaces passed in Rounds 3, 4, and 5, respectively. The overall pass-rate was significantly higher in adult compared to pediatric clinics (86% vs 71%; P < 0.001). In pediatric clinics, blood pressure equipment and computer keyboards in the pulmonary function lab consistently passed, but the exam room patient/visitor chairs consistently failed in all rounds. In adult clinics blood pressure equipment, keyboards in exam rooms and exam tables passed in all rounds and no surface consistently failed. We demonstrate the feasibility of an ATP bioluminescence assay to measure cleanliness of patient care equipment and surfaces in CF clinics. Pass rates improved after cleaning and feedback for certain surfaces. We found that surfaces are more challenging to keep clean in clinics taking care of younger patients.

A DFT and Microkinetic Study of Propylene Selective Oxidation on Cu2O(111) Surface with O2: Chlorinum Effect

AbstractSpin‐polarized density functional theory (DFT) +U calculation was performed to study propylene selective oxidation on Cu2O(111) and Cl−Cu2O(111) surfaces. The mechanism included two pathways: the allylic hydrogen stripping (AHS) pathway and the epoxidation pathway, and acrolein, propylene oxide (PO), propanal and acetone can be formed. The calculated results found that the C3H6*+OO*→OOMMP2*→PO* route can be regarded as the preferred formation route of PO on these two surfaces. On clean surface, acrolein can be regarded as the main product, then other products selectivity follows: acetone&gt;PO&gt;propanal. On Cl−Cu2O(111) surface, acrolein was also the main product, and the apparent activation energy of acrolein (1.97 eV) was approximated to the apparent activation energy of PO (2.04 eV), other products selectivity follows: PO&gt;propanal&gt;acetone, which means that the selectivity of PO can be improved by the effect of Cl. Microkinetic simulation confirm that PO selectivity can be elevated qualitatively, and found that OOMMP2*→PO2*+O* is the rate determining step on pure surface and C3H6*+OO*→OOMMP2* is the rate controlling step on the doped−Cl surface. From this work, it can be found the O−O bond in O2 can be activated effectively by the presence of Cl, enhancing the selectivity of PO.

Glass catfish inspired subaquatic abrasion-resistant anti-fouling window fabricated by femtosecond laser electrodeposition

Abstract Transparent materials utilized as underwater optical windows are highly vulnerable to various forms of pollution or abrasion due to their intrinsic hydrophilic properties. This susceptibility is particularly pronounced in underwater environments where pollutants can impede the operation of these optical devices, significantly degrading or even compromising their optical properties. The glass catfish, known for its remarkable transparency in water, maintains surface cleanliness and clarity despite exposure to contaminants, impurities abrasion, and hydraulic pressure. Inspired by the glass catfish's natural attributes, this study introduces a new solution named subaquatic abrasion-resistant and anti-fouling window (SAAW). Utilizing femtosecond laser ablation and electrodeposition, the SAAW is engineered by embedding fine metal bones structures into a transparent substrate and anti-fouling sliding layer, akin to the sturdy bones among catfish’s body. This approach significantly bolsters the window's abrasion resistance and anti-fouling performance while maintaining high light transmittance. The sliding layer on the SAAW’s surface remarkably reduce the friction of various liquid, which is the reason that SAAW owns great anti-fouling property. The SAAW demonstrates outstanding optical clarity even after enduring hundreds of sandpaper abrasion, attributed to the fine metal bone structures bearing all external forces and protect the sliding layer of SAAW. Furthermore, it exhibits exceptional resistance to biological adhesion and underwater pressure. In a green algae environment, the window remains clean with minimal change in transmittance over one month. Moreover, it retains its wettability and anti-fouling properties when subjected to a depth of 30 meters of underwater pressure for 30 days. Hence, the SAAW prepared by femtosecond laser ablation and electrodeposition presents a promising strategy for developing stable optical windows in liquid environments.

Control of Grain Boundary Formation in Atomically Resolved Nanocrystalline Carbon Monolayers: Dependence on Electron Energy

Abstract In this study, we explore the dynamics of grain boundaries in nanocrystalline carbon monolayers, focusing on their variation with electron beam energy and electron dose rate in a spherical and chromatic aberration-corrected transmission electron microscope. We demonstrate that a clean surface, a high-dose rate, and a 60 keV electron beam are essential for precise local control over the dynamics of grain boundaries. The structure of these linear defects has been evaluated using neural network-generated polygon mapping.

Efficient Fog-Harvesting Origami Fan.

Fog harvesting represents a promising strategy to address the global freshwater shortage. To enhance the water collection efficiency, diverse geometric structures that can effectively drive water droplet movement are essential. Inspired by the Livistona chinensis leaf, which naturally facilitates directional droplet motion through its unique gradually varying V-groove structure, we have developed a novel origami fan structure for fog harvesting through theoretical analysis. A key feature is that we can modulate the speed of droplet transport by adjusting the opening angle of the V-shaped grooves positioned at the outer circumference. Interestingly, the water collection efficiency exhibits a linear correlation with the opening angle. The highest efficiency of the origami fan can reach 5.75 times that of the control group calculated by the projected area and 3.76 times that of the control group calculated by the real area, showcasing its significant potential for enhancing water collection from fog. The simulations demonstrate that the hollow structure enhances the condensation rate of droplets, the geometric gradient of the gradual-variation V-groove drives the condensed droplets to move rapidly on the surface, and the Janus membrane permits the aggregated droplets to transit to the fan's rear side. The synergistic action of these three components ensures a clean surface for the subsequent water-collecting cycle, contributing to the high fog-harvesting efficiency. Given its simple fabrication and superior water transfer efficiency, the origami fan holds substantial promise for widespread application in the field of droplet manipulation.

Interaction of H2S with perfect and O-covered Pd(100) surface: A first-principles study

Using density functional theory (DFT) calculations, we investigated the dissociative mechanism of H2S adsorption and its dissociation on both clean and oxygen covered Pd (100) surface. For adsorption mechanism, the site preference was considered for H2S and HS monomers on both surfaces. The results suggest that H2S is energetically adsorbed on high symmetry sites, particularly the hollow site, on clean surface and top site on O-covered Pd (100) surface. Chemisorption of HS is stronger than H2S at the favorable hollow site on clean surface and O-covered surface. The energy barriers for S–H bond-breaking during the first H2S dehydrogenation are 0.35, 0.07, 0.32, and 0.16 eV, while for second dehydrogenation are 0.32 and 0.30 eV, respectively. On the oxygen-covered surface, the H2S adsorption site transitions from bridge to the top site and their energy barrier for first-order decomposition is 0.05 eV, significantly lesser than that observed on a clean surface. To examine more, the electronic densities of states as well as d-band center model were used to characterize the interaction of adsorbed H2S with the surfaces. Overall, our findings show that H2S decomposition on these surfaces is exothermic and relatively easy, but the presence of surface oxygen hinders the breaking process of H–S bond due to kinetic and thermodynamic factors.

Factors Affecting the Adhesion of Flour Particles to Stainless-steel Surfaces and Vacuum Dry-cleaning

Recent outbreaks and recalls linked to flour-based products have highlighted the need for improved cleaning methods in low-moisture environments. The factors affecting adhesion forces of flour particles, and the vacuum cleaning methodologies to overcome these forces, need to be better understood. The objectives of this study were to: (1) Measure electrostatic charge build-up in flour under different environmental conditions (20, 40, 60% relative humidity at room temperature), (2) quantify how powder size (US standard No. 60–80 or 80–100 mesh), electrostatic charge (charged and uncharged), and relative humidity impact the force required to remove the powder from an electropolished 304 stainless steel coupon (8 × 8 × 0.2 cm), and (3) determine the most effective vacuum nozzle angle (0, 45, 90° relative to the surface) for cleaning. Chargeability (nC) of flour samples was assessed using Faraday cup electrometry, while the surface adhesion force of the flour particles was measured using a custom-built impact tester. The surface cleanliness after vacuum treatments was assessed using ATP (adenosine triphosphate) swabs and a luminometer. Charged flour samples at 20% relative humidity (RH) exhibited a significantly higher charge compared to those at 40 and 60% RH. Within the 60–80 mesh range, charged flour showed higher adhesion rates than uncharged samples at both 20 and 40% RH. However, in the 80–100 mesh range, charged flour did not show a significant difference in adhesion when compared to uncharged samples at any RH level. Additionally, at 60% RH, surface residues measured by ATP were significantly lower for a vacuum angle of 90° than for 0° across both 60–80 mesh and 80–100 mesh size ranges of wheat flour. The vacuum cleaning treatment proved capable of overcoming the increase in adhesion from triboelectric forces; however, trace flour residues were still detected on stainless steel surfaces postvacuuming, indicating that vacuuming alone may be insufficient.

Making Waves: The Progress of Management Strategies for Cleaning and Rinsing of PFAS-Impacted Fire Suppression Systems

Aircraft rescue firefighting (ARFF) vehicles often contain residual levels of per- and polyfluoroalkyl substances (PFAS) due to the global use of legacy and current use of aqueous film-forming foam (AFFF) for class B firefighting. However, numerous countries are transitioning to fluorine-free foam (F3) alternatives. There is, thus, an urgent need to develop efficient methods to rinse and clean interior ARFF surfaces thereby avoiding expensive replacement costs and preventing further discharge of PFAS to the environment. However, the unique self-assembly behavior of amphiphilic PFAS is a complicating factor that can result in measurable levels of PFAS within replacement F3s following cleanout efforts (i.e., the rebound effect). This Making Waves article aims to elucidate the emerging challenges associated with cleanout of impacted ARFF vehicles and introduce the current efforts for PFAS management of rinsate derived from cleanout of impacted fire suppression infrastructure.

Effect of step bottom and waterway on flexural gravity wave scattering

Flexural gravity wave scattering by two semi-infinite non-identical ice sheets, which are separated by a clean water surface, is investigated in the presence of a step bottom topography. The problem is investigated in the cases of (i) intermediate water depth and (ii) shallow water. The effect of two edge conditions, (i) simply supported edge and (ii) free edge, on wave scattering is also analyzed. Employing linear velocity potential theory, the problem is studied in the frequency domain. The physical phenomenon is modeled as a boundary value problem having the Laplace equation as the governing equation, and it is solved using the eigenfunction expansion method. Considering the bottom topography and upper boundary, the fluid domain is divided into three regions, and in each region, velocity potential is expressed in terms of infinite Fourier series. Velocity and pressure are matched at the intermediate surface of two regions, and a system of algebraic equations with unknown coefficients is obtained. The complete solution of the present problem is recognized by solving the system of equations numerically. The energy relation is derived using Green's theorem. The reflection and transmission coefficients are computed and compared with the energy relation to check the accuracy of the present method. For different parameters (depth ratio, clean waterway, and different ice properties), reflection coefficient and transmission coefficient are computed and presented as a function of angular frequency. The value of the reflection coefficient ranges from zero to unity, whereas at certain frequencies, the transmission coefficient attends value more than unity.

Design and Test of Potato Seedling Killing and Residual Film Recycling Integrated Machine

Plastic film mulching technology can effectively enhance crop yield and quality, and the use of mulch has been increasing in recent years; however, the problem of mulch residue is worsening due to the large amount of recycling work and slow natural degradation. In this study, a potato seedling killing and residual film recycling machine is designed to provide good working conditions for potato harvesters before harvesting in response to the problems of difficult separation of film tangles, the low net rate of recycling due to the mixing of residual film with soil, and the high soil content in residual film recycling operations in northwest China. The machine is based on the potato monoculture and double row planting mode in Gansu area. This paper puts forward the overall design scheme and carries out the theoretical analysis and parameter determination of the key components, such as the seedling killing device, the film surface cleaning device, the film unloading device, and so on. Using EDEM software to carry out the virtual simulation test and Design-Expert13 to analyze the test results, we determined the optimal working scheme for the machine, with a forward speed of 0.8 m/s, a film gap of 125 mm, and a spiral stirrer speed of 600 r/min. Based on a field test for verification, the test results show that the machine’s residual film recovery rate was 83.3%, the impurity rate was 3.8%, and the rate of injury to the potatoes was 1.4%. The machine meets the requirements of national and industry standards, and it can simultaneously realize straw crushing, film surface cleaning, residual film recycling, and hydraulic film unloading operations, with better operating results and while reaching the expected results. It can also provide a reference for the design and testing of a seeding and residual film recycling machine.

Electrochemical activation of Pt electrode for efficient and stable anion exchange membrane ammonia electrolyzer

Replacing the oxygen evolution reaction in water electrolysis with ammonia oxidation reaction enables low voltage hydrogen production. Pt is a promising catalyst for the ammonia oxidation reaction due to its superior dehydrogenation and low affinity for *N, but Nads poisoning deactivates the Pt surface. This study proposes a method to improve ammonia oxidation performance and stability through electrochemical activation, introducing cathodic corrosion and recovery conditions. The half-cell results showed a peak current density of 74.2 mA cm−2 and retention ratio of 17 %. Adjusting the lower and upper cell voltage in a membrane electrode assembly based single cell optimized surface cleaning and inhibits further poisoning by O/OHads above 0.75 Vcell. Furthermore, incorporation of recovery conditions can enhance the stability of poisoned electrode compared to that in chronoamperometry test. The results of pulsed ammonia electrolysis tests incorporating recovery conditions suggested a novel approach to practical hydrogen production by stabilizing catalysts with a 83 % Faradaic efficiency at 0.1 A cm−2

Capillary rise on rounded polygon corners of pillar and array structures

Capillary rise, where liquid climbs narrow spaces against gravity, plays an important role in both natural and technological processes. This study investigates capillary wetting in rounded polygon corners, a less-studied area in microfluid mechanics with significant implications for industries such as nanotextured surface cleaning, micro-soldering, food technology, and water harvesting. Through experimental analysis, we examine the relationship between capillary rise height and the geometric parameters of curvature radius and angle in rounded polygonal pillar and array structures. Our findings reveal a direct correlation where the capillary rise height increases as the radius of the corner increases, emphasizing the critical role of corner geometry in enhancing capillary action. This research not only deepens understanding of capillary behavior in complex geometries but also provides valuable insights for optimizing capillary-based applications across. By considering the influence of geometric complexity on capillarity, our study paves the way for innovative approaches in the design and development of efficient systems for fluid manipulation and control.

Synthesis of Amphiphilic Polyacrylates as Peelable Coatings for Optical Surface Cleaning

Optical instruments require extremely high precision, and even minor surface contamination can severely impact their performance. Peelable coatings offer an effective and non-damaging method for removing contaminants from optical surfaces. In this study, an amphiphilic polyacrylate copolymer (PMLEA) was synthesized via solution radical copolymerization using the lipophilic monomer lauryl acrylate (LA) and hydrophilic monomers ER-10, methyl methacrylate (MMA), and butyl acrylate (BA). The structure and molecular weight of the copolymer were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The hydrophilic–lipophilic balance, surface tension, and wettability of the copolymer were analyzed through water titration, the platinum plate method, and liquid contact angle tests. The cleaning performance of the copolymer coating on quartz glass surface contaminants was evaluated using optical microscopy and Ultraviolet-Visible Near-Infrared (UV-Vis-NIR) spectroscopy. The study examined the effect of varying the ratio of LA to ER-10 on the hydrophilicity, lipophilicity, cleaning efficiency, and mechanical properties of the copolymer coating. The results showed that when the mass ratio of LA to ER-10 was 1:2, the synthesized copolymer exhibited optimal performance in removing dust, grease, and fingerprints from quartz glass surfaces. The coating had a tensile strength of 2.57 MPa, an elongation at break of 183%, and a peeling force of 2.07 N m−1.

Surface sterilization and moist storage conditions for recalcitrant seeds of three Asian tree species

Ex situ storage of recalcitrant seeds is challenging, due to seed-desiccation sensitivity. Various moist storage techniques have been used to store seeds, but moist conditions also promote fungal infection. This study determined suitable sterilizing agents for surface cleaning and suitable moist storage conditions for three tree species: Heynea trijuga Roxb. ex Sims, Neocinnamomum caudatum (Nees) Merr., and Phoebe lanceolata (Nees) Nees. We used a factorial design with three factors: sterilizing agents, storage temperature and storage media. There were four surface-sterilization treatments: no sterilization (control), 70% ethanol, 3% NaOCl, and 25% metalaxyl. Seeds were stored with two storage media (moist sand and moist filter paper) and at two storage temperatures (room temperature and 4 °C). Percentage fungal infection and seed germination were recorded. For H. trijuga and P. lanceolata, 3% NaOCl (five-minute soaking) was the best sterilizing agent, whilst N. caudatum had no optimal sterilizing agent. We recommend storing seeds with moist storage media at 4 °C. The best storage media for H. trijuga was moist filter paper, while for P. lanceolata either moist sand or filter paper was suitable. However, N. caudatum seeds should be sown immediately after collection. Our findings emphasize the importance of testing individual species to determine optimal techniques for surface sterilization and storage.

A dual-mechanism pretreatment idea for improving the derived Raman spectrum for (micro)plastic analysis

ABSTRACT Raman spectroscopy is an effective tool for microplastic analysis, but its performance can be limited by weak signals and surface interference. This study aims to enhance derived Raman spectra through chemical surface treatments. Fresh and biofouled plastic debris samples, including polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), were treated overnight with various chemical solutions: 30% H2O2, 5% NaOCl, 5% HCl, and a sequential treatment of 5% HCl followed by 5% NaOCl (HCl:NaOCl). Stereo microscope examinations revealed that single-solution treatments removed some stains but left others behind, while complete stain removal was achieved with the HCl:NaOCl treatment. The control samples exhibited a high fluorescence issue, but oxidation pretreatment effectively reduced this, with 5% NaOCl outperforming 30% H2O2. Despite eliminating fluorescence, residual stains still obscured peak signals. In contrast, the sequential HCl:NaOCl treatment removed almost visible stain, resulting in very clean surfaces, minimal background signals, and significantly higher S/N ratios for peak signals. This study demonstrates that dual-mechanism pretreatments – combining acid dissolution and oxidation – are far more effective than single treatments, benefiting applications that require clean plastic samples for subsequent operations.

Universal droplet propulsion by dynamic surface-charge wetting

Controllable droplet propulsion on solid surfaces plays a crucial role in various technologies. Many actuating methods have been developed; however, there are still some limitations in terms of the introduction of additives, the versatilities of solid surfaces, and the speed of transportation. Herein, we have demonstrated a universal droplet propulsion method based on dynamic surface-charge wetting by depositing oscillating and opposite surface charges on dielectric films with unmodified surfaces. Dynamic surface-charge wetting propels droplets by continuously inducing smaller front contact angles than rear contact angles. This innovative imbalance is built by alternately storing and spreading opposite charges on dielectric films, which results in remarkable electrostatic forces under large gradients and electric fields. The method exhibits excellent droplet manipulation performance characteristics, including high speed (~130 mm/s), high adaptability of droplet volume (1 μL–1 mL), strong handling ability on non-slippery surfaces with large contact angle hysteresis (CAH) (maximum angle of 35°), significant programmability and reconfigurability, and low mass loss. The great application potential of this method has been effectively demonstrated in programmable microreactions, defogging without gravity assistance, and surface cleaning of photovoltaic panels using condensed droplets.

On Self-Positioning and Self-Fixation of Parts Made of Alloys with Shape Memory Effect under Component Assembling

Introduction Violation of mutual positioning and fixation of parts worsens the operation of the equipment. Traditional approaches to solving the problem under consideration have been sufficiently studied: interchangeability of parts and the use of special equipment. Both methods involve a significant number of additional elements and assembly operations. Fixation is often provided by means of force fitting and welding. Disadvantages of these methods include assembly, residual and other stresses, engineering constraints, etc. To solve these problems, alloys with thermoelastic phase transformations are used, which provide shape memory effects (SME) to manifest themselves. This article describes, for the first time, self-positioning and self-fixation using the example of parts specially made from an alloy with SME. Materials and Methods. The pin element under pressing mandrels the blind hole of the cup and enters the seat. The alloy with SME was Ti-55.7wt%Ni. The temperature of the onset of its austenitic transformation was As = 95°C ± 5°C. The elemental composition was determined by a Shimadzu EDX-8000 X-ray fluorescence spectrometer, the phase composition — by a Shimadzu XRD-7000 diffractometer. The temperature was specified through differential scanning calorimetry. The range was 20–300°C, the heating rate was 5 deg/min. A Guide T120 thermal imager and a RangeVision DIY 3D scanner with structured illumination were used. After pressing the pin into the cup at different angles, the alignment and deviations between the axes of the cup and the pin were examined. Then, the cup was heated to 110–120°C, cooled, and control measurements were taken.Results. Values of the deflection angle after pressing were 0.2–11°. With a rigid structure and an installation angle of 0°, the pin deflected in the mounting hole by 0.2–0.5°. The axes shifted and did not intersect. The pin was not always completely pressed in. This indicated uneven deformation of the metal and different stress values around the hole. Such a unit would soon fail. The pin took the required position after heating the cup to 110–120°C (this temperature was higher than at the end of the reverse martensitic transformation). The angular deviation of the axes was noted to be 0.03–0.1°. The maximum misalignment (0.04 mm) corresponded to high positioning accuracy. Heating during the reverse martensitic transformation created internal stresses that returned the initial geometry of the cup. They also formed the forces that positioned and fixed the pin in the hole. That is, it is the parts that provide positioning and fixation (this is selfpositioning and self-fixation).Discussion and Conclusion. For self-positioning and self-fixation of parts due to the shape memory effect, it is necessary to avoid sharp transition lines between the surfaces of parts during design, select rounded corners or fillets, and get a clean surface without burrs. Self-fixation and self-positioning reduce defects and inaccuracies during assembly. The use of certain alloys increases the profitability of equipment production.

Effect of Phase Structure on the Viscoelasticity and Mechanical Properties of Isotactic Polypropylene Multicomponents Polymerized with Non-Conjugated α,ω-Diene.

Increasing of rubber content in isotactic polypropylene/ethylene-propylene rubber (iPP/EPR) alloys can extend the applications of this kind of polyolefin. The EPR content and phase structure of isotactic polypropylene multicomponents have great effect on the viscoelasticity and mechanical properties. iPP/EPR in-reactor alloys with a high EPR content were obtained through the in situ crosslinking of EPR chains with α,ω-diene. The morphological observation results indicate that the crosslinked iPP/EPR in-reactor alloys have a good spherical shape with clean and rough external surfaces. The high EPR content is finely dispersed in the crosslinked iPP/EPR alloys in areas ranging in size from tens of nanometers to several micrometers, which implies that a sufficient crosslinking degree of EPR chains can effectively prevent their aggregation and restrict macro-phase separation. The rheological results show a clear plateau in the terminal region, which reveals an entangled polymer chain network in the crosslinked iPP/EPR alloys. The well-dispersed EPR and the bi-continuous phase structure have a great effect on the mechanical properties of the isotactic polypropylene multicomponent which were assessed.