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M. Najmie, K. Khalid, A. Sidek and M. Jusoh

Density and Ultrasonic Characterization of Oil Palm Trunk Infected by Ganoderma Boninense Disease

Oil palm trunks infected by Ganoderma boninense disease have been studied using density and ultrasonic characterizations. The ultrasonic characterizations have been performed using a commercial ultrasonic instrument at the frequency of 54 kHz. The measurements have been done in 3 zones: inner zone, central zone and peripheral zone. It was found that the stem density of the oil palm infected by Ganoderma boninense disease was reduced by 50% in comparison to the original healthy trunk. From this effect the velocity of the ultrasonic wave propagated through the Longitudinal, Radial, and Tangential directions is lower for the trunk infected by Ganoderma boninense disease compared to a healthy trunk. For the 10 cm thickness of samples, the ultrasonic velocity for all transit directions was in range of 260 - 750 ms-1 for the infected sample, whereas for healthy samples was in the range of 460 - 900 ms-1. These results are very useful for the detection of the area which has been affected by the disease.

Open access

Tomáš Stejskal, Tatiana Kelemenová, Miroslav Dovica, Peter Demeč and Miroslav Štofa

Abstract

The input of this paper lies in displaying possibilities how to determine the condition of a coordinate measuring machine (CMM) based on a large number of repeated measurements. The number of repeated measurements exceeds common requirements for determining positioning accuracy. The total offset in the accuracy of spatial positioning consists of partial inaccuracies of individual axes. 6 basic errors may be defined at each axis. In a triaxial set, that translates into 18 errors, to which an offset from the perpendicularity between the axial pairs must be added. Therefore, the combined number of errors in a single position is 21. These errors are systemic and stem from the machine’s geometry. In addition, there are accidental errors to account for as well. Accidental errors can be attributed to vibrations, mass inertness, passive resistance, and in part to fluctuations in temperature. A peculiar set of systemic errors are time-varying errors. The nature of those errors may be reversible, for instance if they result from influence of temperature or elastic deformation. They can be also irreversible, for example as a result of wear and tear or line clogging, due to loosened connection or permanent deformation of a part post collision. A demonstration of thermal equalizing of the machine’s parts may also be observed in case of failure to adhere to a sufficient time interval from the moment the air-conditioning is turned on. Repeated measurements done on a selected axis with linear interferometer can provide complex information on the CMM condition and also on the machine’s interaction with the given technical environment.

Open access

Slobodan Tabakovic, Milan Zeljkovic and Zoran Milojevic

References [1] Pawlikowski, M., Skalski, K., Haraburda, M. (2003). Process of hip joint prosthesis design including bone remodeling phenomenon. Computers & Structures, 81 (8-11), 887-893. [2] Ramos, A., Completo, A., Relvas, C., Simoes, J.A. (2012). Design process of a novel cemented hip femoral stem concept. Materials & Design, 33, 313-321. [3] Garellick, G., Karrbolm, J., Rogmark, C., Herberts, P. (2011). Annual Report 2010. Swedish Hip Arthroplasty Register. [4] International Organisation for

Open access

Corina Rotar and Laszlo Barna Iantovics

, p. 2435-2437. [10] Weber L., Applications of genetic algorithms in molecular diversity, Current Opinion in Chemical Biology 2.3, 1998, p. 381-385. [11] Arnold F. H., Design by directed evolution, Accounts of chemical research 31.3, 1998, p. 125-131. [12] Cadwell R. C., and Gerald F. J., Randomization of genes by PCR mutagenesis, Genome research 2.1, 1992, p. 28-33. [13] Stemmer W. PC., Rapid evolution of a protein in vitro by DNA shuffling, Nature 370.6488, 1994, p. 389-391. [14] Gartner Z. J., Evolutionary approaches for the

Open access

Aurél Benárd

Abstract

Reykjavík’s largest church, Hallgrímskirkja has become a symbol and an important part of Icelandic national identity. This edifice result of conscious planning process with its location and form reinforce its national significance. Its impact derives from several elements. Buildings symbolizing the identity of communities are usually quite conservative in form. Hallgrímskirkja, however, has distinct individual features that stem from architect Guðjón Samúelsson’s aspiration to express the nation’s identity in a specific architectural form.

Open access

Rudolf Klein

Abstract

This paper investigates the links between some oriental cosmologies and modern architecture, stemming from major non-Western religions, such as Buddhism, Islam and Judaism as well as from Einstein’s theories. It analyses both the direct impact of these concepts, influencing modernism at a theoretical level, and their indirect impact through historic non-Western architecture, mainly Buddhist and Islamic. While modernist theoreticians and architects frequently emphasised functional and technical priorities of modernism, I argue that modernism was far less rational than it is commonly thought, and that it was substantially influenced by non-Western thought, particularly in its early period.

This paper considers two main innovations of modernism resulting from oriental concepts of void: (1) the flat and undecorated façade, the avoidance of traditional ‘façade-discourse’, (2) the promotion of space as the main objective of architecture. The impact of Buddhist, Islamic, Judaic and the Einstenian cosmologies on modernism are considered

Open access

Andrzej Majkowski, Marcin Kołodziej and Remigiusz J. Rak

Abstract

A traditional frequency analysis is not appropriate for observation of properties of non-stationary signals. This stems from the fact that the time resolution is not defined in the Fourier spectrum. Thus, there is a need for methods implementing joint time-frequency analysis (t/f) algorithms. Practical aspects of some representative methods of time-frequency analysis, including Short Time Fourier Transform, Gabor Transform, Wigner-Ville Transform and Cone-Shaped Transform are described in this paper. Unfortunately, there is no correlation between the width of the time-frequency window and its frequency content in the t/f analysis. This property is not valid in the case of a wavelet transform. A wavelet is a wave-like oscillation, which forms its own “wavelet window”. Compression of the wavelet narrows the window, and vice versa. Individual wavelet functions are well localized in time and simultaneously in scale (the equivalent of frequency). The wavelet analysis owes its effectiveness to the pyramid algorithm described by Mallat, which enables fast decomposition of a signal into wavelet components.

Open access

Ryszard Uklejewski, Mariusz Winiecki and Piotr Rogala

Abstract

The proper interaction of bone tissue - the natural porous biomaterial - with a porous coated intra-osseous implant is conditioned, among others, by the implant porous coating poroaccessibility for bone tissue adaptive ingrowth. The poroaccessibility is the ability of implant porous coating outer layer to accommodate the ingrowing bone tissue filling in its pore space and effective new formed bone mineralizing in the pores to form a biomechanically functional bone-implant fixation. The functional features of the microtopography of intra-osseous implant porous surfaces together with the porosity of pore space of the outer layer of the porous coating are called by bioengineers the porostructural-osteoconductive properties of the porous coated implant. The properties are crucial for successful adaptive bone tissue ingrowth and further long-term (secondary) biomechanical stability of the boneimplant interface. The poroaccessibility of intra-osseous implants porous coating outer layers is characterized by - the introduced in our previous papers - set of stereometric parameters of poroaccessibility: the effective volumetric porosity fVef, the index of the porous coating space capacity VPM, the representative surface porosity fSrep, the representative pore size pSrep, the representative angle of the poroaccessibility Wrep and the bone-implant interface adhesive surface enlargement index y. Presented in this paper, an original method of evaluation of the porostructural-osteoconductive properties of intra-osseous implant porous coatings outer layer by means of the parameters of poroaccessibility was preliminary verified during experimental tests performed on the representative examples of porous coated femoral stems and acetabular cups of various hip endoprostheses. The computer-aided stereometric evaluation of the microstructure of implant porous coatings outer layer can be now realized by the authoring application software PoroAccess_1.0 elaborated in our research team in Java programming language

Open access

Andrzej Ryniewicz, Anna Maria Ryniewicz, Tomasz Madej, Jerzy Sładek and Adam Gąska

). Identification, modeling and biotribology of human joints. Cracow, AGH University of Science and Technology Press. [13] Ryniewicz, A.M., Madej, T. (2010). Preclinical tests of endoprostheses of hip joint using finite elements methods. Engineering of Biomaterials, 94(9), 14−23. [14] Sendtner, E., Tibor, S., Winkler, R., Worner, M., Grifka, J., Renkawitz, T. (2010). Stem torsion in total hip replacement. Acta Orthop., 81(5), 579−582. [15] Sendtner, E., Muller, M., Winkler, R., Worner, M., Grifka, J., Renkawitz, T. (2010). Femur

Open access

Amar Rouane and Paul Bru

-318. [6] Haines, D.E., Verow, A. (1990). Observations on electrode-tissue interface temperature and effect on electrical impedance during radiofrequency ablation of ventricular myocardium. Circulation, 82, 1034-1038. [7] Cooper, J.M., et al. (2004). Ablation with an internally irrigated radiofrequency catheter: learning how to avoid stem pops. Heart Rhythm , 1(3), 323-333. [8] Saxon, L.A., Natterson, P., Delurgio, D.D., Shannon, K. (1995). Impedance characteristics of retrograde versus transeptal approaches to radiofrequency ablation