Long-time Service Research Articles

Dynamic Characteristics and Restraint Mechanism of Elastically Restrained Connecting Joints on the Flexible Robotic Manipulator

Connecting joints are significant components in mechanical systems as well as the Cartesian flexible robotic manipulator (FRM) which consists of a flexible arm and a moving base through connecting joints. Uncertain factors, such as unqualified assembly, accidental collision, and longtime service, will reduce the restraint stiffness of the connecting joints and enhance the dynamic nonlinearity of the system subsequently. In this case, the traditional perfectly fixed restrained model cannot reflect the real property of the connecting joints. This paper focuses on the elasticity property of the connecting joints with uncertain restraint stiffness, which is defined as the elastically restrained connecting joints (ERCJ), and investigates the dynamic characteristics and restraint mechanism of the ERCJ. An elastic restrained model is proposed to describe the elasticity property of the connecting joints and determine the elastic restrained region of the ERCJ, and the frequency relationship equation in the elastic restrained region is simultaneously determined and verified. Based on the proposed elastic restrained model and Hamilton’s variational principle, the dynamic model and vibration displacement equation of the FRM with elastically restrained connecting joints (FRMERCJ) are established. The virtual prototype experiment of the FRMERCJ is conducted to verify the dynamic model and reveal the restraint mechanism of the ERCJ. The proposed elastic restrained model in this paper can accurately describe the elasticity property of the connecting joints, and the ERCJ is sensitive to motion velocities especially under higher velocities for higher‐order vibrations in the initial stage. The results are meaningful for the dynamic analysis and vibration control of robotic manipulators.

Self-Healing, antibacterial and sensing nanoparticle coating and its excellent optical applications

Self-healing, antibacterial and metal-ion sensing coatings with nanoparticles were developed using layer-by-layer (LbL) self-assembly technique via host-guest interaction. The coatings consist of MoS2 nanosheets, beta-cyclodextrin (β-CD)-modified poly (ethylenimine) (PEI) and adamantane (AD)-modified poly (acrylic acid) (PAA). Damages to conventional coatings results in cracking and affects the coatings’ ability to maintain antibacterial and sensing qualities. The prepared MoS2/β-CD-PEI/AD-PAA self-healing coatings are not only able to greatly suppress bacterial adhesion and have excellent antibacterial property, particularly under UV light irradiation, but also have a longtime service time. Moreover, the self-healing coatings first applied the fluorescence quenching for detecting heavy metals (Co2+). Fluorescence spectra demonstrated that a linear relationship existed between the fluorescence intensity and the Co2+ concentration with 0∼0.1 ug/mL and the detection limit of Co2+ is 0.018mg/mL. Therefore, the nanoparticle multilayer polyelectrolyte hybrid coatings have a potential application in food industries.

A flexible film type EMAT for inspection of small diameter pipe

Pipe structures are widely applied in industries, and different kinds of defects may occur in the structures during their long-time service. For non-destructive testing of defects in pipes of small diameter, it has to be conducted from the inner side of the pipe when there is no space for detection from the outside or the geometry of the outside tube surface is too complicated. In this work, a flexible film type Electromagnetic acoustic transducer (EMAT) probe with a dual coil configuration is developed. The new probe is flexible and can be inserted into the pipe for inspection. First, the feasibility of the new probe was studied through numerical simulation. Then the feasibility of the proposed flexible EMAT for detection of wall thinning in small diameter pipe was verified experimentally. It was found that the new EMAT method is suitable for the detection of wall thinning defects for small pipes.

Microstructure and mechanical properties of Ti2AlNb cup-shaped part prepared by hot gas forming: determining forming temperature, strain rate, and heat treatment

In aerospace industry, Ti2AlNb-alloy has attracted considerable attentions as a potential material to long-time service at 650–750 °C. In order to study the deformation of the Ti2AlNb component, the cup-shaped specimens were bulged by hot gas forming tests at 985, 950, 930 °C with strain rate of 0.001 s−1 and 970 °C with strain rate of 0.1, 0.01, and 0.001 s−1, respectively. The effects of forming temperature, strain rate, and heat treatment on strain distribution, microstructure, and mechanical property of the Ti2AlNb parts were investigated by thickness measurement, BSE image, EBSD and TEM, and hot tensile tests. With a low forming temperature (930 and 950 °C) or a high strain rate (0.1 and 0.01s-1), the strength of the deformed part is relatively low because of the damage and dislocation. Meanwhile, the mechanical properties of the deformed parts were affected by the heat treatment schemes because of the different O-phase organization. The uniform microstructure with fine lath O-phase grains, equiaxed α2, and matrix B2 phase were obtained by hot gas forming at 970 °C with strain rate of 0.001 s−1 and 2-h heat treatment at 820 °C, presenting enhanced ductility and strengthening behavior, i.e., elongation is 3.2% and yield strength is 787.3 MPa.

Effects of long-time service at high temperature on the material strength and J-R curve of Grade 91 steel

The effects of long-time service at high temperature on the material strength, ductility, and J-Resistance behavior of Mod.9Cr-1Mo (ASME Grade 91) steel were investigated based on tensile and J-R tests with virgin and service-exposed Gr.91 steel specimens. The service-exposed Gr.91 steel specimens were sampled from a tee junction in a reheat steam piping system of an ultra-supercritical (USC) plant in Korea with an accumulated operation time of 73,716h. Comparisons of the test data were made not only between the test results of the virgin materials and service-exposed materials but also between the test results and the material properties in the elevated temperature design (ETD) codes. These test data of yield strength (YS) and tensile strength (TS) for the virgin and service-exposed Gr.91 steel were compared with those of the ETD code, which showed that the current ETD code overestimates the YS and TS properties for long-time service in a non-conservative manner for Gr.91 steel. J-R test data currently not available in ETD codes were produced over a range of temperatures for virgin and service-exposed Gr.91 steel. The effects of long-time service in J-R curve were investigated.

Lake Surface Full of Clouds, and: Quiet, and: Two Robins in Summer

Lake Surface Full of Clouds, and: Quiet, and: Two Robins in Summer Joseph Duemer Note from the Editors: It is with sadness that we report the passing away of Joseph Duemer, at the age of 66, on June 27, 2017. Joe served as Poetry Editor of The Wallace Stevens Journal for twenty years, from 1990 to 2010. He was Professor Emeritus of Humanities at Clarkson University, where he had taught courses in creative writing, literature, popular music, and Buddhism. He published numerous books of poetry, including The Light of Common Day, Customs, Static, and Magical Thinking, and coedited Dog Music: Poetry about Dogs. His poems and criticism appeared in more than seventy-five literary journals. His latest volume of poetry, which he was preparing for publication under the title River with Birds, contains several poems that testify to Stevens’s inspiration on him. We have decided to start our usual selection of poems by reproducing three of these works in celebration of Joe’s poetic career and his longtime service to the Journal. We express our sincere condolences to Joe’s wife, Carole Mathey, and thank her for granting permission to publish the following poems. Lake Surface Full of Clouds In this July evening in the mountains the lake lies within its stone perimeter & light presses against its surface. Wind shapes it & clouds print their exact images on the water, moving. The scent of jack pine fills the air, & the cry of a phoebe, two long notes repeated: thing & song [End Page 278] in their wild fullness full. The world is plainspoken; full of evening light, it is there before me. I lack the perfect mind of an animal, such that I can see myself seeing this. I know myself. I have the stupid human trick of language & a bright penny in my pocket. The tyrant kingbird swerves kit-kit-kit out over the lake’s edge & glances down so that one imagines the lake bottom as conceived from flight. The geography of the lakebed flickers with bronze coins consisting of light & the teal transparency of old glass, the blue iridescence of a trout’s fin in the sunlit shallows swept by shadows. But there is no book of the world—not the night sky’s constellations nor another’s body that we touch with our open hands—neither book nor mirror. We must content ourselves in ourselves in our desolation with the print of a mink’s forepaws on brown sand— left there when [End Page 279] he bent to lick a few streaks of light from the tensed lake. Note: Previously published in American Literary Review; “Lake Surface Full of Clouds” was the winner of the journal’s annual award for best poem in 2012. Quiet “One grows used to the weather.” —Stevens, “The American Sublime” I have always lived here without knowing anything much about anything much, except this slanting light & mild weather, mostly sunny & lulling me to sleep I now see that the light on the bright island is not as I had thought, not without precedent. It has alwaysbeen an exile’slight, trembling. Quiet. Quiet. My phonemes obey the island’s laws of limited motion— short & clear & as careful as needles scoring birdsong on precise devices. Or they will buzz slightly & blur [End Page 280] into the damaged music of language. I have listened but for too long without attention. It has alwaysbeen an exile’slight, trembling. Quiet. Quiet. Light shifts, singing only empty space. A flicker of ultraviolet shivers in the night sky. It is as dry as these dry stalks & shadows of dry stalks askew in soil long given over to waiting—some fleck of water glinting on the faucet’s lip. That will be enough, or almost enough. Light shifts . . . It has alwaysbeen an exile’s light, tense & trembling. Quiet. Quiet. . . . a sharp breeze shifts direction, adjusting leaves & stirring unbroken branches. Waking, the weather veers predictably enough toward beauty (which must be acknowledged) & loneliness (now devoid of the sublime) but I drift in & out of [End Page 281] shadows cast by stately cumulus. Here I am. It has alwaysbeen an exile’slight, trembling. Quiet. Quiet...

Study on characteristics and mathematical models of stress relaxation for metal O-rings

The metal O-ring is effectively applied to extreme conditions and long-term uses for several decades, where conventional seals cannot meet the requirements. During the long-time service, the stress relaxation of the metal O-ring has been confirmed to be a potential damage to the sealing performance. By analyzing the sealing mechanism and the problem of the stress relaxation of the metal O-ring, a model has been developed to study its stress relaxation. The model includes the contact model, the stress–strain model, and the dynamic equation of stress relaxation. Based on the classical elastic-plastic model for two contact rough surfaces, the contact model of sealing zone is developed, by which the mechanical and geometric parameters of the sealing zone can be obtained for the initial state after the assembling. In the stress–strain model, the determination of stress and strain in the metal O-ring is performed by means of a simplified closed-form solution. The dynamic equation of stress relaxation using the stress-creep rate equation is developed, and is solved by combination of the contact model and the stress–strain model. The equation can be adopted for stress relaxation analysis of the metal O-ring at any time. After a validation of the model by comparison with experiments, a parametric study is presented. Simulation results corresponding with the mathematical models explain how the stress relaxation characteristic of the metal O-ring is influenced by a number of parameters.

Whole Inorganic Hermetic Packaging Technology Using Localized Induction Heating for Deep Ultraviolet Light-Emitting Diodes

A uniform, reproducible, and whole inorganic hermetic packaging technology using localized induction heating and its application to deep ultraviolet light-emitting diode (DUV-LED) packaging with glass cap have been proposed and demonstrated. By localized induction heating and inorganic packaging materials, the DUV-LED was rapidly packaged, which eliminates thermal damages during packaging process and avoids UV aging during its long-time service. At certain conditions, such as a treating period from 2 to 16 s and an output power from 1 to 6 kW, the bonding between ceramics and glass using Sn/Cu solder was achieved. The experimental measurement results indicate that localized induction heating packaging improves the electrical and optical characteristics of DUV-LED compared to global heating packaging.

Peer-review acknowledgements

Peer-review acknowledgements

The Court of the Grand Prince of Muscovy and the Court of France in the 14th–16th Centuries: Comparing the Incomparable? (Государев двор России и королевский двор Франции в XIV–XVI вв.

This study compares the organization, function, and personnel of the royal courts in Muscovy and France in the fourteenth through sixteenth centuries, a period vital to the consolidation of monarchical power in both states. The article traces the rise and parallel development of the ruler’s court in Muscovy and France, and makes the case for significant similarities between the two. In both, membership in the court elite was rooted in similar social and political structures (in Muscovy, membership in the elite was rooted in birth and longtime service to the ruler, while in France it was rooted in birth and proximity to the king), and both courts were positioned in similar ways at the center of politics and religious culture. The similarities between Muscovy and France become especially apparent during the reigns of Ivan IV and Henry III, when both monarchs instituted reforms aimed at strengthening central monarchical power and institutions, and when the rulers were confronting significant centrifugal pressures among the nobility and regional elites. The article argues that the court of the Grand Prince of Muscovy in the second half of fifteenth and first half of the sixteenth centuries was in function, structure, and ritual form very close to that of many other Renaissance courts of Europe, particularly to that of France.

A Method of Defect Diagnosis for Integrated Grounding System in High-Speed Railway

An integrated grounding system (IGS) plays a significant role in reliable operations of a high-speed railway (HSR). The defect problems of grounding conductors have been frequently occurring due to the long-time service of an IGS and the large current from a traction system. Therefore, defect diagnosis should be conducted. Considering the topology of an IGS and the distribution feature of the surface potential, a method is proposed here to diagnose and locate the defect of the IGS. The grounding conductors can be classified into two main categories, i.e., the grounding grid in a traction substation and the integrated grounding line along a track. The surface potentials, which resulted from the IGS, can be investigated through the electromagnetic calculation of the grounding conductors. Thus, the relationship between the surface potentials and the levels of conductor corrosion can be quantified. As a result, the breakpoint location and the levels of the conductor corrosion of the grounding conductors can be determined by the surface potentials calculated. Finally, the IGS model is simulated in the current distribution, electromagnetic fields, grounding, and soil structure (CDEGS) analysis software, and the results verify the accuracy of the proposed model.

Framework for Enhancing Mobile Availability of RESTful Services

Providing users of mobile devices uninterrupted access to web services in unstable network conditions continues to be a problem. Numerous methods for service caching have been proposed; however, most studies fail to consider two crucial factors: (1) Context of network connectivity: Smartphones are used in a variety of wireless network conditions, such as high-speed networks, unstable networks, and areas without an available network connection; and (2) Service failure handling: Current service caching mechanisms are able to deal with temporary unavailability, but they cannot handle long-time service failures or malfunctions. This paper proposes a connectivity-aware, risk-driven (CARD) approach to the delivery of RESTful services. The CARD approach is encapsulated in the form of a client-side library for use by mobile applications (apps) to invoke backend RESTful services in a highly-available manner. The CARD approach has two main features: 1) the ability to perform actions specific to the network conditions, such as the application of prefetch services and caching services when connected to high speed wireless networks to ensure that cached services are used for unstable wireless networks, and allowing users to request cached service responses from other users when no wireless network can be accessed. 2) The proposed risk-driven analysis method enables the provision of a reasonable service recovery plan when the original service malfunctions. Experiments demonstrate that the proposed CARD approach expands the availability of service and shortens service response times under a variety of network conditions.

Influences on the thermomechanical fatigue crack growth of the nickel alloy 617*

Abstract The following contribution deals with the experimental investigation and theoretical evaluation of fatigue crack growth under isothermal and non-isothermal conditions at the nickel alloy 617. The microstructure and mechanical properties of alloy 617 are influenced significantly by the thermal heat treatment and the following thermal exposure in service. Hence, a solution annealed and a long-time service exposed material condition is studied. The crack growth measurement is carried out by using an alternate current potential drop system, which is integrated into a thermomechanical fatigue (TMF) test facility. The measured fatigue crack growth rates results in a function of material condition, temperature and load waveform. Furthermore, the results of the non-isothermal tests depend on the phase between thermal and mechanical load (in-phase, out-of-phase). A fracture mechanic based, time dependent model is upgraded by an approach to consider environmental effects, where almost all model parameters represent directly measureable values. A consistent description of all results and a good correlation with the experimental data can be achieved.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure.

Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

Degradation Behavior and Mechanism of HMA Aggregate

Abstract The degradation behavior and mechanism of aggregate used for hot mix asphalt (HMA) mixtures has been investigated in this study. Laboratory tests, including the crushing test, Marshall compactor test, and Superpave gyratory compactor test, were used to evaluate the degradation behavior of single-size aggregate and/or graded aggregates. In order to verify the laboratory test results, the degradation of field HMA materials extracted from asphalt pavements after long-time service was also evaluated. The stress-transfer model for an aggregate skeleton was analyzed in order to provide a fundamental understanding of the stress distribution and degradation mechanism of the aggregate system. The results indicate that the degradation of the aggregate gradation is not random and has a fixed internal trend. The 4.75 mm aggregate proved to be the demarcation point between coarse and fine aggregate. During the degradation process, coarse aggregate tends to break into graded aggregate to form a well-balanced skeleton to bear an external load, and the 4.75 mm aggregate plays a key role in the graded aggregate. The crushing test and Superpave gyratory compactor test proved to be easily done and promising for capturing the degradation of aggregate and the gradation of HMA. The variation in the retained percentage of 4.75 mm aggregate and the breakdown ratio of the original aggregate and/or gradation can quantitatively depict the degradation of HMA aggregate.

Degradation behavior of aggregate skeleton in stone matrix asphalt mixture

The degradation behavior of aggregate skeleton in stone matrix asphalt mixture was investigated based on theoretical analysis, laboratory test and field materials evaluation. A stress-transfer model was established to provide the fundamental understanding of the stress distribution and degradation mechanism of stone matrix asphalt (SMA) aggregate skeleton. Based on the theoretical analysis, crushing test and superpave gyratory compactor (SGC) test were used to evaluate the degradation behavior of aggregate skeleton of SMA. To verify the laboratory test results, gradation analysis was also conducted for the field materials extracted from SMA pavements after long-time service. The results indicate that the degradation of SMA aggregate skeleton is not random but has fixed internal trend and mechanism. Special rule is found for the graded fine aggregates generated from coarse aggregate breakdown and the variation of 4.75 mm aggregate is found to play a key role in the graded aggregates to form well-balanced skeleton to bear external loading. The variation of 4.75 mm aggregate together with the breakdown ratio of aggregate gradation can be used to characterize the degradation behavior of aggregate skeleton. The crushing test and SGC test are proved to be promising in estimating the degradation behavior of SMA skeleton.

Redesign and Renewal

I feel honored to have been selected to serve as the next Editor-in-Chief of Health Education & Behavior (HE&B). I follow in the footsteps of a storied group of previous chief editors—including Lowell Levin, Lawrence Green, Noreen Clark, and Marc Zimmerman—whose commitment, dedication, and editorial acumen have served HE&B well over its 37 volumes of publication. I want to thank Marc Zimmerman for his 12 years of outstanding leadership as the journal’s most recent chief editor. Marc strengthened HE&B’s impact factor and catapulted it into the top quarter of the ranking of journals in public, environmental, and occupational health. I also want to thank associate editors Jesus Ramirez-Valles, who will be moving as a newly elected Trustee of the Society for Public Health Education (SOPHE) to service on the Publications Committee, and Lisa Lieberman, who will continue as a member of the Editorial Board of HE&B. Finally, but not least, I wish to acknowledge and thank Teresa Vogel for her long-time and superb service as HE&B’s editorial assistant, as well as SAGE Publications and the editorial production and marketing team in Los Angeles, whose continuing talented support of the journal’s growth and development has enabled HE&B to become the preeminent journal of behavioral and social science in public health that it is today. Changes in editorial leadership at any academic journal, however, invariably present the opportunity to rethink purpose and direction. Toward that end, I have undertaken a process with our Editorial Board to review with key stakeholder groups, including members of SOPHE and the authors and reviewers with whom the journal has worked, how we can strengthen the journal’s relevance and impact in light of SOPHE’s current mission and strategic plan and in recognition of the daunting public health challenges we face, not only in United States and North America but globally as well. I have worked with SAGE Publications during the past 6 months to make several important changes to the journal that will be evident in this issue. First, we have revisited the style and format of HE&B. This issue reveals a face-lift that freshens the design and layout, which, we hope, improves readability while preserving the classically elegant design that has characterized HE&B since the late 1990s when the journal went from publishing quarterly to six issues a year. The new cover has been designed by Janet Kiesel, senior graphic designer, in the SAGE Art Department. Subtle changes retain the branding of HE&B while creating a modern look. The title is now displayed in the font Perpetua and the two-color abstract design creates greater depth of field and motion. Although the SOPHE logo has always appeared within the four-square graphic, the addition of a new HE&B acronym in the opposite corner creates a balanced and complete logo for the journal. Behind the attractive new cover you will find what Denise Royle, production editor supervisor of the HE&B production team at SAGE, has implemented to achieve a subtle, but fresh, new look for the contents of HE&B. This includes a redesign of the layout for each article’s masthead and abstract, the introduction of a two-column format in which the Times New Roman text is set, and an increase in trim size to 81⁄2 by 11, all in an effort to both streamline and make more contemporary HE&B’s appearance. We have also improved the author notes element and each article now includes a statement of conflict of interests and author disclosure that appears at the end. Second, we have made some changes to the scope of content and in our capacity to communicate with our readership. With the development and success of HE&B’s sister journal, Health Promotion Practice (HPP), we have decided to discontinue Practice Notes, a section of HE&B that provided an important outlet for brief reports of innovative practice at a time when such reports were not available to the field. In an effort to reach out and draw in an entire new generation of young scholars who now routinely use social networking sites and blogs to communicate and collaborate, HE&B is now on Facebook and Twitter. And in the coming months, we will be considering additional new features that can improve the impact of the journal. I believe the changes we have made, as well as those that we are contemplating, will improve readability and relevance and will provide more opportunity for dialogue from the field about the science and scholarship that we choose to publish. Finally, thanks to the expert guidance and support provided by Katja Werlich Fried, publishing editor, and Charles Rink, editorial assistant for journals at SAGE, we have been able to move seamlessly to the SAGE Track editorial peer-review system, HE&B’s new online submission portal at Manuscript Central, which is powered by ScholarOne. In addition, in an

Spray-coated superhydrophobic coatings with regenerability

With the aim of creating superhydrophobic coatings with longtime service life, to avoid the permanent destroying under practical conditions, a simple technique for fabrication of superhydrophobic coatings with regenerability was developed using a facile and convenient method of spraying. The as-prepared poly(furfuryl alcohol)/calcium hydroxide (PFA/Ca(OH)2) composite coatings were used to fabricate superhydrophobic coatings after modification with potassium stearate solution. When the superhydrophobic coating surfaces were destroyed, the damaged surfaces could be restored completely after being modified again, and the superhydrophobicity of the surfaces was regenerated at the same time. Additionally, the regenerative superhydrophobic coatings could perhaps show the most promise for a wide array of applications as they can be applied to various surfaces without limitations of size and shape, they do not typically require expensive materials and complicated application methods, and they can be easily restored after being destroyed.

Inspirations from the Geographical Review: Jean Gottmann's “Why the Skyscraper?”

Editors' note: Larry lost his battle against pancreatic cancer in September 2009. When we invited him, some months before his death, to prepare this essay he eagerly agreed, despite his worsening health. We acknowledge with gratitude his longtime service as a member of the Geographical Review Editorial Board, as a Councilor of the American Geographical Society, and as a professor of geography at San Diego State University. In many ways he was himself an inspiration.

Poly(trialkylsilyl methacrylate)s: A family of hydrolysable polymers with tuneable erosion profiles

Polymers containing hydrolytically labile trialkylsilyl ester side groups were synthesised via a conventional and a controlled radical polymerization. The trialkylsilyl methacrylate monomer unit was chosen for its capacity to hydrolyse into basic, acid or sea water varying the hydrophilic character of the resulting polymer backbone with time. The hydrolysis or saponification reaction of the ester bond of the trialkylsilyl methacrylate was monitored through a 1H NMR study showing the formation of siloxane side-products. Several copolymers and polymer blends were prepared as matrixes for controlled erodible systems. Their capacity to hydrolyse was demonstrated through SEM investigations with selective dissolution of free films containing hydrolysable copolymers and PMMA blends. Well-defined random and diblock copolymers with methyl methacrylate were investigated to show the effect of the microstructure on the erosion properties of the corresponding coatings. Poly(methyl methacrylate-b-tert-butyldimethylsilyl methacrylate) diblock copolymers synthesised through the RAFT process showed a better control of the erosion with a constant erosion rate over a long-time service in sea water at pH = 8.2. In addition, experiments showed that the erosion rate could be modulated by varying the molar proportion of hydrolysable side groups onto the copolymer backbone and the weight amount of copolymers mixed with PMMA in toluene solution.