Methodology for Photovoltaic Modules Characterization and Shading Effects Analysis

This work describes the methodology, basic procedures and instrumental employed by the Solar Energy Laboratory at Universidade Federal do Rio Grande do Sul for the determination of current-voltage characteristic curves of photovoltaic modules. According to this methodology, I-V characteristic curves were acquired for several modules under diverse conditions. The main electrical parameters were determined and the temperature and irradiance influence on photovoltaic modules performance was quantified. It was observed that most of the tested modules presented output power values considerably lower than those specified by the manufacturers. The described hardware allows the testing of modules with open-circuit voltage up to 50 V and short-circuit current up to 8 A.

A Well Stated Time Domain Integral Representation for Elastodynamic Analysis and Applications

This article discusses three possible ways to derive time domain boundary integral representations for elastodynamics. This discussion points out possible difficulties found when using those formulations to deal with practical applications. The discussion points out recommendations to select the convenient integral representation to deal with elastodynamic problems and opens the possibility of deriving simplified schemes. The proper way to take into account initial conditions applied to the body is an interesting topict shown. It illustrates the main differences between the discussed boundary integral representation expressions, their singularities and possible numerical problems. The correct way to use collocation points outside the analyzed domain is carefully described. Some applications are shown at the end of the paper, in order to demonstrate the capabilities of the technique when properly used.

Experimental Vibration Characteristics of a Beam with Nonlinear Support Using Receptance Coupling Analysis

This paper applies the Multi-Harmonic Nonlinear Receptance Coupling Approach (MUHANORCA) (Ferreira 1998) to evaluate the frequency response characteristics of a beam which is clamped at one end and supported at the other end by a nonlinear cubic stiffness joint. In order to apply the substructure coupling technique, the problem was characterised by coupling a clamped linear beam with a nonlinear cubic stiffness joint. The experimental results were obtained by a sinusoidal excitation with a special force control algorithm where the level of the fundamental force is kept constant and the level of the harmonics is kept zero for all the frequencies measured.

Analysis of Regular and Irregular Dynamics of a Non Ideal Gear Rattling Problem

This paper presents a study on the dynamics of the rattling problem in gearboxes under non-ideal excitation. The subject has being analyzed by a number of authors such as Karagiannis and Pfeiffer (1991), for the ideal excitation case. An interesting model of the same problem by Moon (1992) has been recently used by Souza and Caldas (1999) to detect chaotic behavior. We consider two spur gears with different diameters and gaps between the teeth. Suppose the motion of one gear to be given while the motion of the other is governed by its dynamics. In the ideal case, the driving wheel is supposed to undergo a sinusoidal motion with given constant amplitude and frequency. In this paper, we consider the motion to be a function of the system response and a limited energy source is adopted. Thus an extra degree of freedom is introduced in the problem. The equations of motion are obtained via a Lagrangian approach with some assumed characteristic torque curves. Next, extensive numerical integration is used to detect some interesting geometrical aspects of regular and irregular motions of the system response.

Analysis of open CNC architecture for machine tools

The evolution of digital circuit technology, leadind to higher speeds and more reliability allowed the development of machine controllers adapted to new production systems (e.g., Flexible Manufacturing Systems - FMS). Most of the controllers are developed in agreement with the CNC technology of the correspondent machine tool manufacturer. Any alterations or adaptation of their components are not easy to be implemented. The machine designers face up hardware and software restrictions such as lack of interaction among system's elements and impossibility of adding new function. This is due to hardware incompatibility and to software not allowing alterations in the source program. The introduction of open architecture philosophy propitiated the evolution of a new generation of numeric controllers. This brought the conventional CNC technology to the standard IBM - PC microcomputer. As a consequence, the characteristics of the CNC (positioning) and the microcomputer (easy of programming, system configuration, network communication etc) are combined. Some researchers have addressed a flexible structure of software and hardware allowing changes in the hardware basic configuration and all control software levels. In this work, the development of open architecture controllers in the OSACA, OMAC, HOAM-CNC and OSEC architectures is described.

Hot tool temperature analysis though infrared images

Textile manufacture occupies a prominent place in the national economy. Because of its importance researches have been made on the development of new materials, equipment and methods used in the production process. The cutting of textiles starts in the basic stage, to be followed by the process of the making of clothes and other articles. In the hot cutting of fabric, one of the variables of great importance in the control of the process is the contact temperature between the tool and the fabric. This work presents a technique for the measurement of the temperature based on the processing of infrared images. With this purpose, it was developed a system which is composed of an infrared camera, a framegrabber PC board and a software which analyses the punctual temperature in the cut area enabling the operator to achieve the necessary control of other variables involved in the process.

On non-ideal and non-linear portal frame dynamics analysis using bogoliubov averaging method

We apply the Bogoliubov Averaging Method to the study of the vibrations of an elastic foundation, forced by a Non-ideal energy source. The considered model consists of a portal plane frame with quadratic nonlinearities, with internal resonance 1:2, supporting a direct current motor with limited power. The non-ideal excitation is in primary resonance in the order of one-half with the second mode frequency. The results of the averaging method, plotted in time evolution curve and phase diagrams are compared to those obtained by numerically integrating of the original differential equations. The presence of the saturation phenomenon is verified by analytical procedures.

Microwave-assisted solvent extraction and analysis of shikimic acid from plant tissues

A better method for determination of shikimate in plant tissues is needed to monitor exposure of plants to the herbicide glyphosate [N-(phosphonomethyl)glycine] and to screen the plant kingdom for high levels of this valuable phytochemical precursor to the pharmaceutical oseltamivir. A simple, rapid, and efficient method using microwave-assisted extraction (MWAE) with water as the extraction solvent was developed for the determination of shikimic acid in plant tissues. High performance liquid chromatography was used for the separation of shikimic acid, and chromatographic data were acquired using photodiode array detection. This MWAE technique was successful in recovering shikimic acid from a series of fortified plant tissues at more than 90% efficiency with an interference-free chromatogram. This allowed the use of lower amounts of reagents and organic solvents, reducing the use of toxic and/or hazardous chemicals, as compared to currently used methodologies. The method was used to determine the level of endogenous shikimic acid in several species of Brachiaria and sugarcane (Saccharum officinarum) and on B. decumbens and soybean (Glycine max) after treatment with glyphosate. The method was sensitive, rapid and reliable in all cases.

Computer programs for analysis of droplets sprayed on water sensitive papers

The use of water-sensitive papers is an important tool for assessing the quality of pesticide application on crops, but manual analysis is laborious and time-consuming. Thus, this study aimed to evaluate and compare the results obtained from four software programs for spray droplet analysis in different scanned images of water-sensitive papers. After spraying, papers with four droplet deposition patterns (varying droplet spectra and densities) were analyzed manually and by means of the following computer programs: CIR, e-Sprinkle, DepositScan and Conta-Gotas. The diameter of the volume and number medians and the number of droplets per target area were studied. There is a strong correlation between the values measured using the different programs and the manual analysis, but there is a great difference between the numerical values measured for the same paper. Thus, it is not advisable to compare results obtained from different programs.

Target audience analysis in cyber domain

This thesis aims to find an effective way of conducting a target audience analysis (TAA) in cyber domain. There are two main focal points that are addressed; the nature of the cyber domain and the method of the TAA. Of the cyber domain the object is to find the opportunities, restrictions and caveats that result from its digital and temporal nature. This is the environment in which the TAA method is examined in this study. As the TAA is an important step of any psychological operation and critical to its success, the method used must cover all the main aspects affecting the choice of a proper target audience. The first part of the research was done by sending an open-ended questionnaire to operators in the field of information warfare both in Finland and abroad. As the results were inconclusive, the research was completed by assessing the applicability of United States Army Joint Publication FM 3-05.301 in the cyber domain via a theory-based content analysis. FM 3- 05.301 was chosen because it presents a complete method of the TAA process. The findings were tested against the results of the questionnaire and new scientific research in the field of psychology. The cyber domain was found to be “fast and vast”, volatile and uncontrollable. Although governed by laws to some extent, the cyber domain is unpredictable by nature and not controllable to reasonable amount. The anonymity and lack of verification often present in the digital channels mean that anyone can have an opinion, and any message sent may change or even be counterproductive to the original purpose. The TAA method of the FM 3-05.301 is applicable in the cyber domain, although some parts of the method are outdated and thus suggested to be updated if used in that environment. The target audience categories of step two of the process were replaced by new groups that exist in the digital environment. The accessibility assessment (step eight) was also redefined, as in the digital media the mere existence of a written text is typically not enough to convey the intended message to the target audience. The scientific studies made in computer sciences and both in psychology and sociology about the behavior of people in social media (and overall in cyber domain) call for a more extensive remake of the TAA process. This falls, however, out of the scope of this work. It is thus suggested that further research should be carried out in search of computer-assisted methods and a more thorough TAA process, utilizing the latest discoveries of human behavior. ---------------------------------------------------------------------------------------------------------------------------------- Tämän opinnäytetyön tavoitteena on löytää tehokas tapa kohdeyleisöanalyysin tekemiseksi kybertoimintaympäristössä. Työssä keskitytään kahteen ilmiöön: kybertoimintaympäristön luonteeseen ja kohdeyleisöanalyysin metodiin. Kybertoimintaympäristön osalta tavoitteena on löytää sen digitaalisesta ja ajallisesta luonteesta juontuvat mahdollisuudet, rajoitteet ja sudenkuopat. Tämä on se ympäristö jossa kohdeyleisöanalyysiä tarkastellaan tässä työssä. Koska kohdeyleisöanalyysi kuuluu olennaisena osana jokaiseen psykologiseen operaatioon ja on onnistumisen kannalta kriittinen tekijä, käytettävän metodin tulee pitää sisällään kaikki oikean kohdeyleisön valinnan kannalta merkittävät osa-alueet. Tutkimuksen ensimmäisessä vaiheessa lähetettiin avoin kysely informaatiosodankäynnin ammattilaisille Suomessa ja ulkomailla. Koska kyselyn tulokset eivät olleet riittäviä johtopäätösten tekemiseksi, tutkimusta jatkettiin tarkastelemalla Yhdysvaltojen armeijan kenttäohjesäännön FM 3-05.301 soveltuvuutta kybertoimintaympäristössä käytettäväksi teorialähtöisen sisällönanalyysin avulla. FM 3-05.301 valittiin koska se sisältää kokonaisvaltaisen kohdeyleisöanalyysiprosessin. Havaintoja verrattiin kyselytutkimuksen tuloksiin ja psykologian uusiin tutkimuksiin. Kybertoimintaympäristö on tulosten perusteella nopea ja valtava, jatkuvasti muuttuva ja kontrolloimaton. Vaikkakin lait hallitsevat kybertoimintaympäristöä jossakin määrin, on se silti luonteeltaan ennakoimaton eikä sitä voida luotettavasti hallita. Digitaalisilla kanavilla usein läsnäoleva nimettömyys ja tiedon tarkastamisen mahdottomuus tarkoittavat että kenellä tahansa voi olla mielipide asioista, ja mikä tahansa viesti voi muuttua, jopa alkuperäiseen tarkoitukseen nähden vastakkaiseksi. FM 3-05.301:n metodi toimii kybertoimintaympäristössä, vaikkakin jotkin osa-alueet ovat vanhentuneita ja siksi ne esitetään päivitettäväksi mikäli metodia käytetään kyseisessä ympäristössä. Kohdan kaksi kohdeyleisökategoriat korvattiin uusilla, digitaalisessa ympäristössä esiintyvillä ryhmillä. Lähestyttävyyden arviointi (kohta 8) muotoiltiin myös uudestaan, koska digitaalisessa mediassa pelkkä tekstin läsnäolo ei sellaisenaan tyypillisesti vielä riitä halutun viestin välittämiseen kohdeyleisölle. Tietotekniikan edistyminen ja psykologian sekä sosiologian aloilla tehty tieteellinen tutkimus ihmisten käyttäytymisestä sosiaalisessa mediassa (ja yleensä kybertoimintaympäristössä) mahdollistavat koko kohdeyleisöanalyysiprosessin uudelleenrakentamisen. Tässä työssä sitä kuitenkaan ei voida tehdä. Siksi esitetäänkin että lisätutkimusta tulisi tehdä sekä tietokoneavusteisten prosessien että vielä syvällisempien kohdeyleisöanalyysien osalta, käyttäen hyväksi viimeisimpiä ihmisen käyttäytymiseen liittyviä tutkimustuloksia.

Comparative analysis of leaf cell-wall polysaccharides of Dialypetalanthus fuscescens and Bathysa meridionalis: evidence of biochemical similarities between Dialypetalanthaceae and Rubiaceae-Cinchonoideae

Dialypetalanthus fuscescens is an Amazonian endemic species with problematic taxonomic position. This neotropical rainforest tree belongs to the monospecific Dialypetalanthaceae. In the present work, we analysed the leaf cell-wall polysaccharide composition of Dialypetalanthus fuscescens and compared it to that of Bathysa meridionalis (Rubiaceae-Cinchonoideae). Glycosyl composition and glycosyl-linkage analysis indicated that both species have similar cell wall composition. Arabinogalactans were the major component of the pectic polysaccharides and xylans, although being reported in minor amounts in dicots, were found to be the predominant hemicellulosic polysaccharide in cell walls of both species. These findings are in agreement with previous data on cell wall composition reported for Rubiaceae and corroborate the current suggestion of the possible link between this family and Dialypetalanthaceae.

Ultrastructural analysis of in vitro direct and indirect organogenesis

This is a comparative study of the ultrastructural characteristics of the cells involved in the organogenesis in vitro of Bauhinia forficata Link (indirect system) and Glycine max (L.) Merrill (direct system). B. forficata calli after 30 days culture and G. max meristemoids after 10 days culture were prepared for ultrastructural analysis using conventional methods. Concentrically arranged rough endoplasmic reticulum (RER) and plastids containing starch grains were seen during G. max and B. forficata organogenesis. The amitotic process, the presence of plastids around the nucleus and nuclear envelope with conspicuous pores were found in B. forficata.

Structural analysis of the vegetation on a highland granitic rock outcrop in Southeast Brazil

Granitic rock outcrops of the Brazilian southeast are either coastal or inland. The latter can often have high altitudes, such as in the summits of "Serra do Mar" and "Serra da Mantiqueira", where they are known as "Campos de Altitude". The landscape on these high altitude plateaux is often a mosaic of shrubs and treelets within a bunchgrass matrix, with sparse pteridophytes and other herbs, interspersed with variable extensions of rock outcrops. Despite the pervasiveness of rock outcrops in the Brazilian landscape, studies on the structural analysis of the vegetation on such formations are scarce. This study aimed to analyze the structure of the vegetation on a highland granitic rock outcrop in "Parque Estadual da Serra do Brigadeiro", state of Minas Gerais, Southeast Brazil (42°20' - 42°40' S and 20°20' - 21°00' W, 1,722 m of elevation ). Quantitative parameters of absolute and relative frequency and dominance (cover) were estimated. The group analysis used the Jaccard similarity index. Trilepis lhotzkiana, Panicum sp. 1, and Vellozia variegata presented the highest relative frequencies, relative dominances and importance values. These three species, along with Dyckia bracteata, Rhynchospora emaciate, and Tibouchina cf. manicata, represented 98.3% of the relative dominance. The remaining 1.7% referred to 22 remaining species. The distinction among quadrats within formed groups by cluster analysis was due to the great number of low frequency species.

Morphometric analysis of the Brasiliorchis picta complex (Orchidaceae)

One of the largest genera of Orchidaceae in the Neotropics with about 450 species, Maxillaria presents several taxonomic uncertainties about its generic circumscription and the delimitation of species groups, mainly due to the large variability of some species. The present study aims at verifying the morphological variation and species delimitation in the Brasiliorchis picta complex, a recent new genus derived from Maxillaria, using morphometric multivariate analysis. A total of 340 specimens belonging to six species (B. chrysantha (Barb. Rodr.) R.B. Singer, S. Koehler & Carnevali, B. gracilis (Lodd.) R.B. Singer, S. Koehler & Carnevali, B. marginata (Lindl.) R.B. Singer, S. Koehler & Carnevali, B. picta (Hook.) R. Singer, S. Koehler & Carnevali, B. porphyrostele (Rchb. f.) R.B. Singer, S. Koehler & Carnevali and B. ubatubana (Hoehne) R.B. Singer, S. Koehler & Carnevali) were analyzed using multivariate methods (PCA, CVA, DA, and Cluster Analysis with UPGMA). B. gracilis shows the largest morphological discontinuity, mainly due to its smaller size. The other species tend to form distinct groups, but intermediate characteristics between pairs of species induce overlaps among the individuals of different species and thus confuse the distinction of each one. Hybridization and geographic distribution can be involved in the differentiation of the species and lineages in this complex. Because the species classified a priori in this work cannot be recognized by the quantitative characters measured here, such other tools as geometric morphometry and molecular data should be employed in future works to clarify species relationships in this complex.