Dietmar Adam, Fritz Kopf · 2026
In this paper compaction technologies are considered in form of rollers equipped with different kinds of exciters. Compaction of soil, fill material, etc. normally takes place by vibratory rollers, whereby the vibration of the drum is caused by a rotating mass excenter. In the last years dynamic rollers with different types of excitation where developed. The paper is focused on the oscillatory roller, the VARIO roller, and the automatically controlled VARIO CONTROL roller. Furthermore, the paper contains roller-integrated compaction control methods in order to check continuously the compaction success during compaction with different dynamic roller types. Finally, the application of new compaction technologies and case histories, where roller-integrated continuous compaction controls (CCC) were used, are reported.
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Ronald W. Miller · 2005
This chapter is different from the original; new works, findings, and best practices from various investigators since 1997 have been added. The interested reader will have to wait for a comprehensive book (in preparation now) to link numerous journal articles, chapters, and investigative works for technology completeness.
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Ronald L. Miller · Drugs and the pharmaceutical sciences · 2005
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Ronald W. Miller · 2016
INTRODUCTION Since the publication of theHandbook of Pharmaceutical Granulation Technology, Second Edition, late 2005, the world’s economy has slowed and capital expansion in worldwide pharmaceutical industry, particularly in oral solid dosage forms, has suffered (1). A number of pharmaceutical drug companies, large and small, have had and are still reducing staffs, selling manufacturing sites or merging. During the last three years, new drug development has slowed as well, as is evident for fewer new drug approvals by the U.S. Food and Drug Administration. In spite of the apparent pharmaceutical industry economic and the innovative drug downturn trends temporarily, I do believe, the important need for dry granulation technology keeps growing in the pharmaceutical industry, as well as in other industries.
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National Cancer Institute · Definitions · 2020
T he act of forming granules by mechanically applying pressure by rollers to form a compact that is subsequently milled and screened resulting in dry granules.
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Ervina Hadžović · edoc (University of Basel) · 2008
1. Summary \nDirect compaction requires a very good flowability and compressibility of the materials. Those parameters become even more critical if the formulation contains large amount of active substance. To overcome these problems, several alternatives have been used. Roller compaction is a very attractive technology in the pharmaceutical industry. It is a fast and efficient way of producing granules, especially suitable for moisture sensitive materials. The intention of this work was to understand the effect of roller compaction on the tablet properties. In the literature it is often shown that after roller compaction a material tend to loose mechanical strength. This phenomenon is affected by deformation behavior of the materials exposed to roller compaction. Plastic deformable materials are particularly sensitive because of the limiting binding potential which may be consumed in the first compression step by increasing particle size and decreasing specific surface area. However, materials which undergo fragmentation under pressure showed less or even no loss of tabletability after roller compaction. The loosing of mechanical strength is called loss of reworkability or loss of tabletability. To diminish or even eliminate loss of reworkability the crucial moment is the development of a correct and robust formulation. If excipients with adequate properties, regarding an active material, are chosen it is possible to hold mechanical strength of the tablets. Another problem that could take place during roller compaction is disruption of crystal lattice and changing of polymorphic form of the material. Polymorphic transformation may occur as a result of applied pressure during roller compaction or even due to double compaction after tableting. Due to the fact that Theophylline exists as two polymorphic forms of anhydrate and as monohydrate, it was used as a model drug. Two grade of Theophylline anhydrate: Theophylline anhydrate powder (THAP) and Theophylline anhydrate fine powder (THAFP) were employed in order to check if there is difference in compactibility and tablet properties produced from the same material with different particle size distribution. There is the risk that during the compaction cycle hydrate looses water and transforms to anhydrate, therefore Theophylline monohydrate (THMO) was compacted. Microcrystalline cellulose (MCC) was chosen as a material to combine with THAP, THAFP and THMO because it is \n \nwidely used pharmaceutical excipient and its mechanical properties are well \nunderstood. \nDue to the importance of active material and excipientes properties on the process \nparameters of roller compaction the materials were characterized in detail. \nDifferential scanning calorimetry (DSC) and X-Ray analysis confirmed that roller \ncompaction, milling and tableting did not influence polymorphic / pseudoplymorphic \nforms of THAP, THAFP and THMO. It is well known that various materials have a \ndifferent behavior under compression pressure. In order to see effect of roller \ncompaction on compressibility and compactibility of the materials after roller \ncompaction various mathematical equation were applied. The most used equations \nfor checking the compressibility of a material are Heckel and modified Heckel \nequation. Compactibility of the materials with and without roller compaction was \ndetermined by measuring the tensile strength of the tablets produced from the \ngranules and the original materials. Leuenberger equation, which connects \ncompressibility and compactibility parameters and this equation, was also applied in \nthis study. \nAccording to the equations which are responsible for compressibility measuring, \nTHAP, THAFP, THMO and MCC belong to the same group and showed plastic \nbehavior when they were exposed to pressure. However, when tensile strength of \ntablets produced by direct compaction and roller compaction was measured, \ndifferences in behavior were occurred. Tensile strength of MCC tablets after roller \ncompaction was extremely decreased, while THAP, THAFP and THMO tablets \nshowed slightly decreased tensile strength. The phenomenon of loosing tableting \nproperties during roller compaction is characteristic for plastic materials and since the \ntablets produced from THAP, THAFP and THMO showed almost the same tensile \nstrength after roller compaction led to the conclusion that these materials showed \nsignificantly less plastic behavior than MCC. Tablets composed of the mixture of 10% \nTheophylline and 90% MCC showed the best compressibility and compactibility \nproperties. \nIn order to check the influence of roller compaction on disintegration and dissolution \nrate, tablets with the same properties were produced from the original materials and \ngranules produced by roller compaction at pressure of 20 and 30 bars. Tablets of \nTHAP, THAFP and THMO produced by direct compaction and roller compaction \nshowed very slow disintegration because these materials do not show any \n \ndisintegrant properties and tablets were more dissolvable. Adding MCC to the tablets \nformulation extremely improved disintegration, especially if tablets were produced by \nroller compaction. During the dissolution process anhydrate underwent \ntransformation to monohydrate. However, during the dissolution process THAP and \nTHAFP were transformed to monohydrate and showed slightly higher dissolution rate \nthan THMO. This could be explained by different particles shape and surface area of \nTHMO and hydrate which was obtained from initially anhydrate surface. Due to the \nfaster disintegration rate of the tablets produced by roller compaction, dissolution rate \nof these tablets was higher as well. As it was demonstrated that roller compaction \nimproves disintegration time and dissolution rate of the tablets it could be proposed \nas a method of choice for immediate release tablets.
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Ronald W. Miller, Abhay Gupta, Kenneth R. Morris · 2005
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Peggi L. Clouston · 1919
This article reviews the technique of roller compacted concrete pavement construction (RCCP), which is relatively new in New Zealand, but is already proving to be a good alternative to conventional methods. Technical Report No 07 of the New Zealand Cement and Concrete Association summarises the state-of-the-art of this method. Like conventional concrete pavements, RCCP provides a heavy-duty pavement structure; properly made, RCCP behaves very much like conventional concrete, but it has different surface finishes and several other differences. As RCCP uses less cement, its construction cost is typically 10% to 40% less. Pavement design and detailing concepts, developed and refined over many decades for concrete roads, can be applied to RCCP roads with some confidence. The thickness design concepts, and the design and construction of the subgrade and any base layers, used for RCCP pavements, are like those developed for undowelled, unreinforced concrete pavements. Very high production rates are desirable to allow continuous operation of the paving process, to minimise problems that otherwise occur. The final surface of an RCCP layer is generally a medium-textured exposed aggregate finish, without the smooth layer of fines and cement found on screeded plastic concrete; this makes it excellent for industrial applications.
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Subgrade Geosynthetic Reinforcement, David White, Pavana Vennapusa et al. · 2012
is to be the nation’s premier institution for developing fundamental knowledge of earth mechanics, and creating innovative technologies, sensors, and systems to enable rapid, high quality, environmentally friendly, and economical construction of roadways, aviation runways, railroad embankments, dams, structural foundations, fortifications constructed from earth materials, and related geotechnical applications. Disclaimer Notice The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. The opinions, findings and conclusions expressed in this publication are those of the authors and not necessarily those of the sponsors. The sponsors assume no liability for the contents or use of the information contained in this document. This report does not constitute a standard, specification, or regulation. The sponsors do not endorse products or manufacturers. Trademarks or manufacturers ’ names appear in this report only because they are considered essential to the objective of the document. Non-Discrimination Statement Iowa State University does not discriminate on the basis of race, color, age, religion, national
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Zaichenko, Stefan Volodymyrovych, Shevchuk, Stepan Prokopovych, Harnets, Volodymyr Mykolaiovych · The Scientific Issues of Ternopil Volodymyr Hnatiuk National Pedagogical University Series pedagogy · 2019
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Shuo-Huan Hsu · 2008
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Chuan‐Yu Wu, W.-L. Hung, A.M. Miguélez-Morán et al. · International Journal of Pharmaceutics · 2010
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Mono KURITA, Yasuhira Aoyagi, Toru Okumura · 1988
This paper describes a fundamental study on the compaction characteristics of Roller Compacted Concrete (RCC) in the fresh state during vibration through a laboratory test and a field experiment. Through the laboratory test carried out to examine the effects of the vibration factors, the required minimum acceleration to consolidate RCC densely was determined. The relationship between the densities of RCC and the vibration factors (frequency, amplitude) is shown, and the time-dependent variation properties of the surface settlement of RCC are explained. Through the field experiment carried out to investigate the vibration properties, the dynamic wave propagation of vibration in the inner part of fresh RCC was found. The settlement properties in the inner part of fresh RCC during vibrating roller compaction are explained.
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Sarsvatkumar Patel, Aditya Mohan Kaushal, Arvind K. Bansal · European Journal of Pharmaceutics and Biopharmaceutics · 2008
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Osama Mahmah, M.J. Adams, Chalak Omar et al. · International Journal of Pharmaceutics · 2019
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Andrey Zinchuk, Matthew P. Mullarney, Bruno C. Hancock · International Journal of Pharmaceutics · 2003
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Tai-Sung Yoo, Ernest T. Selig · Journal of the Geotechnical Engineering Division · 1980
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Johannes Pistrol, Mario Hager, Fritz Kopf et al. · Acta Geotechnica · 2024
Abstract The compaction success of vibratory roller compaction can be assessed by systems for continuous compaction control (CCC) or intelligent compaction (IC) which calculate soil stiffness-proportional quantities based on measurements of the motion behavior of the vibrating drum. However, state-of-the-art intelligent compaction meter values (ICMV) do not only depend on the stiffness of the soil but are also strongly influenced by machine and process parameters. In this paper, the methodology for determining an advanced ICMV is presented, in which the mechanical properties of the soil, the process parameters and geometric relationships in the contact area between the drum and the soil are directly included in the calculation. The methodology is explained on the example of measurement data from a compaction test conducted on sandy gravel with a heavy single-drum roller. The results of the novel ICMV are compared with those of the most widely used IC systems.
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CHEE SZE NAM · National University of Singapore · 2010
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Mark J. Thompson · 2007
The feasibility of using variable feedback control intelligent compaction to evaluate the properties of subgrade and granular pavement layers was investigated at US 14 in Minnesota. The study was comprised of proof testing strips using an Ammann vibratory smooth drum roller. The soil of the test strips was then evaluated with the various portable testing devices commonly used for quality control and acceptance. The research findings documented in this paper focused on: (1) relationships between intelligent compaction rollermeasured soil stiffness and various in-situ measurement values, (2) performance of variable feedback control of amplitude and frequency, and (3) comparison of roller-measured stiffness with rut depth from test rolling. The study findings show that roller-measured stiffness can be empirically related to in-situ compaction measurements, but that the strength of correlation depends heavily on the range of values over which the measurements are taken. The intelligent compaction system also identified areas of unstable subgrade material similar to test rolling.
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