Complicações locais após a injeção de silicone líquido industrial: série de casos

OBJETIVO: analisar uma série de casos de pacientes submetidos à injeção de silicone líquido industrial de maneira clandestina e por pessoas não habilitadas. MÉTODOS: análise retrospectiva de prontuários de pacientes atendidos no período de setembro de 2003 a dezembro de 2010. Foram avaliados: sexo, idade, local e volume de silicone injetado, tempo decorrido entre a aplicação e as manifestações clínicas, complicações, tratamento e evolução. Definiu-se como precoce as manifestações ocorridas até 30 dias da injeção e manifestações tardias após este período. RESULTADOS: Foram atendidos 12 pacientes, oito eram do sexo masculino, sendo sete transexuais. O volume injetado variou de 5ml a 2000ml, sendo desconhecido em três casos. Os locais mais frequentemente utilizados para injeção foram a região de coxas e glúteos. Oito casos apresentaram manifestações precoces, com quadros de inflamação e/ou infecção. Foi necessária a realização de desbridamento cirúrgico em cinco casos. Três pacientes com histórico de injeção na região mamária foram submetidas à adenomastectomia. Houve um óbito por quadro de choque séptico refratário. CONCLUSÃO: O uso do silicone líquido industrial deve ser totalmente contraindicado como material de preenchimento e modificação do contorno corporal, podendo apresentar graves complicações e até mesmo óbito.

Electrocoagulation in the treatment of industrial waters and wastewaters

Chemical coagulation is commonly used in raw water and wastewater treatment plants for the destabilisation of pollutants so that they can be removed in the subsequent separation processes. The most commonly used coagulation chemicals are aluminium and iron metal salts. Electrocoagulation technology has also been proposed for the treatment of raw waters and wastewaters. With this technology, metal cations are produced on the electrodes via electrolysis and these cations form various hydroxides in the water depending on the water pH. In addition to this main reaction, several side reactions, such as hydrogen bubble formation and the reduction of metals on cathodes, also take place in the cell. In this research, the applications of electrocoagulation were investigated in raw water treatment and wastewater applications. The surface water used in this research contained high concentrations of natural organic matter (NOM). The effect of the main parameters – current density, initial pH, electric charge per volume, temperature and electrolysis cell construction – on NOM removal were investigated. In the wastewater treatment studies, the removal of malodorous sulphides and toxic compounds from the wastewaters and debarking effluents were studied. Also, the main parameters of the treatment, such as initial pH and current density, were investigated. Aluminium electrodes were selected for the raw water treatment, whereas wastewaters and debarking effluent were treated with iron electrodes. According to results of this study, aluminium is more suitable electrode material for electrocoagulation applications because it produces Al(III) species. Metal ions and hydroxides produced by iron electrodes are less effective in the destabilisation of pollutants because iron electrodes produce more soluble and less charged Fe(II) species. However, Fe(II) can be effective in some special applications, such as sulphide removal. The resulting metal concentration is the main parameter affecting destabilisation of pollutants. Current density, treatment time, temperature and electrolysis cell construction affect the dissolution of electrodes and hence also the removal of pollutants. However, it seems that these parameters have minimal significance in the destabilization of the pollutants besides this effect (in the studied range of parameters). Initial pH and final pH have an effect on the dissolution of electrodes, but they also define what aluminium or iron species are formed in the solution and have an effect on the ζ-potential of all charged species in the solution. According to the results of this study, destabilisation mechanisms of pollutants by electrocoagulation and chemical coagulation are similar. Optimum DOC removal and low residual aluminium can be obtained simultaneously with electrocoagulation, which may be a significant benefit of electrocoagulation in surface water treatment compared to chemical coagulation. Surface water treatment with electrocoagulation can produce high quality water, which could be used as potable water or fresh water for industrial applications. In wastewater treatment applications, electrocoagulation can be used to precipitate malodorous sulphides to prevent their release into air. Technology seems to be able to remove some toxic pollutants from wastewater and could be used as pretreatment prior to treatment at a biological wastewater treatment plant. However, a thorough economic and ecological comparison of chemical coagulation and electrocoagulation is recommended, because these methods seem to be similar in pollutant destabilisation mechanisms, metal consumption and removal efficiency in most applications.

Comparative analysis of the frequency and the severity of diagnosed lesions between pedestrians struck by motor vehicles and other blunt trauma mechanisms victims

ABSTRACTObjective:to compare the frequency and the severity of diagnosed injuries between pedestrians struck by motor vehicles and victims of other blunt trauma mechanisms.Methods:retrospective analysis of data from the Trauma Registry, including adult blunt trauma patients admitted from 2008 to 2010. We reviewed the mechanism of trauma, vital signs on admission and the injuries identified. Severity stratification was carried using RTS, AIS-90, ISS e TRISS. Patients were assigned into group A (pedestrians struck by motor vehicle) or B (victims of other mechanisms of blunt trauma). Variables were compared between groups. We considered p<0.05 as significant.Results:a total of 5785 cases were included, and 1217 (21,0%) of which were in group A. Pedestrians struck by vehicles presented (p<0.05) higher mean age, mean heart rate upon admission, mean ISS and mean AIS in head, thorax, abdomen and extremities, as well as lower mean Glasgow coma scale, arterial blood pressure upon admission, RTS and TRISS. They also had a higher frequency of epidural hematomas, subdural hematomas, subarachnoid hemorrhage, brain swelling, cerebral contusions, costal fractures, pneumothorax, flail chest, pulmonary contusions, as well as pelvic, superior limbs and inferior limbs fractures.Conclusion:pedestrian struck by vehicles sustained intracranial, thoracic, abdominal and extremity injuries more frequently than victims of other blunt trauma mechanism as a group. They also presented worse physiologic and anatomic severity of the trauma.

Interaction with industrial customers from a project selling company's perspective

This thesis studied the issue of interaction in industrial buyer-seller relationships. The aim of the thesis was to study the interaction from the seller’s perspective, especially from a project selling company’s perspective. The purpose of the thesis was to offer suggestions for the case company on how to improve interaction. The theoretical part of the study introduced the interaction framework of buyer-seller interaction, and the concept of interaction mechanisms. The focus was on studying the seller’s ways and means to utilize the interaction mechanisms. A case study research was conducted in the empirical part of the study, in which interaction in the case company was observed at a general level and through three different projects. The case company of the study was a project selling company. The case study data was gathered through individual interviews. Content Analysis was used as a research method for analyzing the case study data. Based on the case study findings, the results were drawn. The results indicated what should be done, in order to develop interaction in the case company. Finally, suggestions were provided for the case company on how to improve interaction, and a suggested interaction model was established for the case company. Although the thesis studied the topic from the viewpoint of only one specific company, it also offers outlook for other seller companies to improve their interaction.

Applications of Industrial Statistics

This dissertation examines knowledge and industrial knowledge creation processes. It looks at the way knowledge is created in industrial processes based on data, which is transformed into information and finally into knowledge. In the context of this dissertation the main tool for industrial knowledge creation are different statistical methods. This dissertation strives to define industrial statistics. This is done using an expert opinion survey, which was sent to a number of industrial statisticians. The survey was conducted to create a definition for this field of applied statistics and to demonstrate the wide applicability of statistical methods to industrial problems. In this part of the dissertation, traditional methods of industrial statistics are introduced. As industrial statistics are the main tool for knowledge creation, the basics of statistical decision making and statistical modeling are also included. The widely known Data Information Knowledge Wisdom (DIKW) hierarchy serves as a theoretical background for this dissertation. The way that data is transformed into information, information into knowledge and knowledge finally into wisdom is used as a theoretical frame of reference. Some scholars have, however, criticized the DIKW model. Based on these different perceptions of the knowledge creation process, a new knowledge creation process, based on statistical methods is proposed. In the context of this dissertation, the data is a source of knowledge in industrial processes. Because of this, the mathematical categorization of data into continuous and discrete types is explained. Different methods for gathering data from processes are clarified as well. There are two methods for data gathering in this dissertation: survey methods and measurements. The enclosed publications provide an example of the wide applicability of statistical methods in industry. In these publications data is gathered using surveys and measurements. Enclosed publications have been chosen so that in each publication, different statistical methods are employed in analyzing of data. There are some similarities between the analysis methods used in the publications, but mainly different methods are used. Based on this dissertation the use of statistical methods for industrial knowledge creation is strongly recommended. With statistical methods it is possible to handle large datasets and different types of statistical analysis results can easily be transformed into knowledge.

A Method for reducing throughput-time in industrial electronics

Lyhyet toimitusajat tuovat yrityksille kilpailuetua nopeasti muuttuvassa teollisuusympäristössä. Tämän diplomityön ensisijaisena tavoitteena on löytää kirjallisuuden avulla yrityksen käyttöön soveltuva menetelmä, joka soveltuu systemaattiseen läpimenoaikojen lyhentämiseen. Tärkeää on myös varmistaa valitun menetelmän soveltuvuus kohdeyrityksen ympäristöön. Työn toisena tavoitteena on ymmärtää, että minkälaisella panostuksella yhden päivän läpimenoaika voidaan saavuttaa. Kirjallisuustutkimuksen avulla on valittu tarkoitukseen sopiva toimintamalli. Menetelmä on testattu yhdellä tuotantolinjalla ja saadut tulokset sekä palaute osoittavat, että se näyttäisi soveltuvan kohdeyrityksen käyttöön. Tuotantolinjalle on tehty toimintasuunnitelma yhden päivän toimitusajan saavuttamiseksi vuoden 2013 aikana. Haasteen laajuutta koko kohdeyrityksessä on tutkittu erillisessä ideointisessiossa. Session tulosten perusteella on tehty prioriteettilista, joka antaa käsityksen toimitusajan merkittävän lyhentämisen vaatimuksista. Yleisesti ottaen kysynnän vaihtelun hallinta on suurin haaste, mutta useita ratkaisuvaihtoehtoja tämän hallitsemiseksi on tunnistettu.

Design of RFID-system for industrial after-sale service

RFID-tekniikka on radiotaajuudella toimivaa etätunnistusta, jossa hyödynnetään RFID-tunnisteiksi kutsuttuja tageja, sekä RFID-lukijoita. RFID-tekniikan käyttökohteet ovat erittäin laajat. Tässä kandidaatintyössä tutkitaan RFID-tekniikan hyödyntämismahdollisuuksia teollisuuden huoltopalvelusuhteessa. Työ keskittyy huollettavien laitteiden etätunnistamiseen mobiileja RFID-lukijoita hyödyntäen. Laitteiden tiedot noudetaan olemassa olevasta tietokannasta web-käyttöliittymän kautta. Koska laitteet koostuvat pääosin metallista, joudutaan tunnistetyyppien valintaa pohtimaan tarkasti. Metallipinnat sekä nesteet vaikuttavat erittäin negatiivisesti useiden tunnisteiden lukuetäisyyteen. Työssä keskitytään vaadittavan järjestelmän suunnittelemiseen aikaisempia tutkimuksia hyödyntäen, mutta itse järjestelmän toteutus ei kuulu tähän kandidaatintyöhön. Lopussa järjestelmän alustava suunnitelma esitellään.

Sivistyksestä sivilisaatioon. Kulttuurikäsitys J. V. Snellmanin historiallisessa ajattelussa

From Bildung to Civilisation. Conception of Culture in J. V. Snellman’s Historical Thinking The research explores Johan Vilhelm Snellman’s (1806–1881) conception of culture in the context of his historical thinking. Snellman was a Finnish, Swedish-speaking journalist, teacher and thinker, who held a central position in the Finnish national discourse during the nineteenth century. He has been considered as one of the leading theorists of a Finnish nation, writing widely about the themes such as the advancement of the national education, Finnish language and culture. Snellman is already a widely studied person in Finnish intellectual history, often characterised as a follower of G. W. F. Hegel’s philosophical system. My own research introduces a new kind of approach on Snellman’s texts, emphasising the conceptual level of his thought. With this approach, my aim is to broaden the Finnish research tradition on conceptual history. I consider my study as a cultural history of concepts, belonging also to the field of intellectual history. My focus is on one hand on the close reading of Snellman’s texts and on the other hand on contextualising his texts to the European intellectual tradition of the time. A key concept of Snellman’s theoretical thinking is his concept of bildning, which can be considered as a Swedish counterpart of the German concept of Bildung. The Swedish word incorporated all the main elements of the German concept. It could mean education or the so-called high culture, but most fundamentally it was about the self-formation of the individual. This is also the context in which Snellman’s concept of bildning has often been interpreted. In the study, I use the concept of bildning as a starting point of my research but I broaden my focus on the cognate concepts such as culture (kultur), spirit (anda) and civilisation. The purpose of my study is thus to illustrate how Snellman used and modified these concepts and from these observations to draw a conclusion about the nature of his conception of culture. Snellman was an early Finnish philosopher of history but also interested in the practice of the writing of history. He did not write any historical presentations himself but followed the publications in the field of history and introduced European historical writing to the Finnish, Swedish-speaking reading audience in his newspapers. The primary source material consists of different types of Snellman’s texts, including philosophical writings, lecture material, newspaper articles and private letters. I’m reading Snellman’s texts in the context of other texts produced both by his Finnish predecessors and contemporaries and by Swedish, German and French writers. Snellman’s principal philosophical works, Versuch einer spekulativen Entwicklung der Idee der Persönlichkeit (1841) and Läran om staten (1842), were both written abroad. Both of the works were contributions to contemporary debates on the international level, especially in Germany and Sweden. During the 1840s and 1850s Snellman had two newspapers of his own, Saima and Litteraturblad, which were directed towards the Swedish-speaking educated class. Both of the newspapers were very popular and their circulations were among the largest of their day in Finland. The topics of his articles and reviews covered literature, poetry, philosophy and education as well as issues concerning the economic, industrial and technical development in Finland. In his newspapers Snellman not only brought forth his own ideas but also spread the knowledge of European events and ideas to his readers. He followed very carefully the cultural and political situation in Western Europe. He also followed European magazines and newspapers and was well acquainted with German, French and also English literature – and of course Swedish literature to with which he had the closest ties. In his newspapers Snellman wrote countless number of literary reviews and critics, introducing his readers to European literature. The study consists of three main chapters in which I explore my research question in three different, yet overlapping contexts. In the first of these chapters, I analyse Snellman’n theoretical thinking and his concepts of bildning, kultur, anda and civilisation in the context of earlier cultural discourse in Finland as well as the tradition of German idealistic philosophy and neo-humanism. With the Finnish cultural discourse I refer to the early cultural discussion in Finland, which emerged after the year 1809, when Finland became an autonomous entity of its own as a Grand Duchy of Russia. Scholars of the Academy of Turku opened a discussion on the themes such as the state of national consciousness, the need for national education and the development of the Finnish language as a national language of Finland. Many of these academics were also Snellman’s teachers in the early years of his academic career and Snellman clearly formulated his own ideas in the footsteps of these Finnish predecessors. In his theoretical thinking Snellman was a collectivist; according to him an individual should always be understood in connection with the society, its values and manners, as well as to the traditions of a culture where an individual belongs to. In his philosophy of the human spirit Snellman was in many ways a Hegelian but his notion of education or ‘bildning’ includes also elements that connect him with the wider tradition of German intellectual history, namely the neo-humanist tradition and, at least to some extent, to the terminology of J. G. Herder or J. G. Fichte, for example. In this chapter, I also explore Snellman’s theory of history. In his historical thinking Snellman was an idealist, believing in the historical development of the human spirit (Geist in German language). One can characterise his theory of history by stating that it is a mixture of a Hegelian triumph of the spirit and Herderian emphasis on humanity (Humanität) and the relative nature of ‘Bildung’. For Snellman, the process of ‘bildning’ or ‘Bildung’ is being realised in historical development through the actions of human beings. Snellman believed in the historical development of the human civilization. Still Snellman himself considered that he had abandoned Hegel’s idea about the process of world history. Snellman – rightly or wrongly – criticised Hegel of emphasising the universal end of history (the realisation of the freedom of spirit) at the expense of the historical plurality and the freedom of each historical era. Snellman accused Hegel of neglecting the value and independency of different historical cultures and periods by imposing the abstract norm, the fulfilment of the freedom of spirit, as the ultimate goal of history. The historicist in Snellman believed in the individuality of each historical period; each historical era or culture had values, traditions and modes of thought of its own. This historicist in Snellman could not accept the talk about one measure or the end of history. On the other hand Snellman was also a universalist. He believed that mankind had a common task and that task was the development of ‘Bildung’, freedom or humanity. The second main chapter consists of two parts. In the first part, I explore the Finnish nationalistic discourse from the cultural point of view by analysing the notions such as a nation, national spirit or national language and showing how Snellman formulated his own ideas in a dialogic situation, participating in the Finnish discourse but also reacting to international discussions on the themes of the nation and nationality. For Snellman nationality was to a great extent the collective knowledge and customs or practices of the nation. Snellman stated that nationality is to be considered as a form of ‘bildning’. This could be seen not simply as affection for the fatherland but also for the mental identity of the nation, its ways of thinking, its practices, national language, customs and laws, the history of the nation. The simplest definition of nationality that Snellman gives is that nationality is the social life of the people. In the second part of the chapter I exam Snellman’s historical thinking and his understanding about historical development, interaction between different nations and cultures in the course of history, as well as the question of historical change; how do cultures or civilisations develop and who are the creators of culture? Snellman did not believe in one dominating culture but understood the course of history as a dialogue between different cultures. On the other hand, his views are very Eurocentric – here he follows the ideas of Hegel or for example the French historian François Guizot – for Snellman Europe represented the virtue of pluralism; in Europe one could see the diversity of cultures which, on the other hand, were fundamentally based on a common Christian tradition. In the third main chapter, my focus is on the writing of history, more precisely on Snellman’s ideas on the nature of history as a science and on the proper way of writing historical presentations. Snellman wrote critics on the works of history and introduced his readers to the writing of history especially in France, Sweden and German-speaking area – in some extend also in Britain. Snellman’s collectivistic view becomes evident also in his reviews on historical writing. For Snellman history was not about the actions of the states and their heads, nor about the records of ruling families and battles fought. He repeatedly stressed that history is a discipline that seeks to provide a total view of a phenomenon. A historian should not only collect information on historical events, since this information touches only the surface of a certain epoch or civilisation; he has to understand an epoch as totality. This required an understanding about the major contours in history, connections between civilisations and an awareness of significant turning points in historical development. In addition, it required a holistic understanding about a certain culture or historical era, including also the so-called inner life of a specific nation, a common people and their ways of life. Snellman wrote explicitly about ‘cultural history’ in his texts, referring to this kind of broad understanding of a society. In historical writing Snellman found this kind of broader view from the works of the French historians such as François Guizot and Jules Michelet. In all of these chapters, I elaborate the conceptual dimension of Snellman’s historical thinking. In my study I argue that Snellman not only adopted the German concepts of Bildung or Kultur in his own thinking but also developed the Swedish concepts in a way that include personal and innovative aspects. Snellman’s concept of bildning is not only a translation from ‘Bildung’ but he uses the Swedish concept in a versatile way that includes both the moral aspect of human development and social dimension of a human life. Along with ‘bildning’ Snellman used also the terms ‘kultur’ and ‘civilisation’ when referring to the totality of a certain nation or historical era, including both the so-called high culture (arts, science, religion) and the modes of thought as well as ways of life of the people as a whole. Unlike many of his Finnish contemporaries, Snellman did not use civilisation as a negative concept, lacking the moral essence of German term ‘Bildung’ or ‘Kultur’. Instead, for Snellman civilisation was a neutral term and here he comes close to the French tradition of using the term. In the study I argue that Snellman’s conception of culture in fact includes a synthesis of the German tradition of ‘Bildung’ and the French tradition of ‘civilisation’.

Diversification benefits for a Finnish non-industrial private forest investor: Real Estate Investment Trusts in the USA

This thesis examined both domestic and international forest investment options for a Finnish non-industrial private forest investor. The focus was on forest-based investment instruments. The influence of movements of currency exchange rates on foreign returns were also taken into account. Annual data from 1995 to 2011 was used. The main portfolio optimization model in this study was the Mean-Variance model but the results were also validated by using the Value at Risk and Expected Shortfall models. In addition, the exchange rate risk hedging was established by using one-week-maturity forward contracts. The results suggested that 75 % of the total wealth should be invested in Finnish private forests and the rest, 25 %, to a US REIT, in this case Rayonier. With hedging, the total return on the portfolio was 7.21 % (NIPF 5.3%) with the volatility of 6.63 % (NIPF 7.9%). Taxation supported US investments in this case. As a conclusion, a Finnish private forest investor may, as evidenced, benefit in diversifying a portfolio using REITs in the US.

Customer Segmentation in Industrial Markets - CASE: Labelstock Company

The aim of this thesis is to study segmentation in industrial markets and develop a segmenting method proposal and criteria case study for a labelstock manufacturing company. An industrial company is facing many different customers with varying needs. Market segmentation is a process for dividing a market into smaller groups in which customers have the same or similar needs. Segmentation gives tools to the marketer to better match the product or service more closely to the needs of the target market. In this thesis a segmentation tool proposal and segmenting criteria is case studied for labelstock company’s Europe, Middle East and Africa business area customers and market. In the developed matrix tool different customers are planned to be evaluated based on customer characteristic variables. The criteria for the evaluating matrix are based on the customer’s buying organizations characteristics and buying behaviour. There are altogether 13 variables in the evaluating matrix. As an example of variables there are loyalty, size of the customer, estimated growth of the customer purchases and customer’s decision-making and buying behaviour. These characteristic variables will help to identify market segments to target and the customers belonging to those segments.

Profiling the Value of Industrial Maintenance Services

Industrial maintenance can be executed internally, acquired from the original equipment manufacturer or outsourced to a service provider, and this concludes in many different kind of business relationships. To maximize the total value in a maintenance business relationship it is important to know what the partner values. The value of maintenance services can be considered to consist of value elements and the perceived total value for the customer and the service provider is the sum of these value elements. The specific objectives of this thesis are to identify the most important value elements for the maintenance service customer and provider and also to recognize where the value elements differ. The study was executed as a statistical analysis using the survey method. The data has been collected by an online survey sent to 345 maintenance service professionals in Finland. In the survey, four different types of value elements were considered: the customer’s high critical and low critical items and the service provider’s core and support service. The most valued elements by the respondents were reliability, safety at work, environmental safety, and operator knowledge. The least valued elements were asset management factors and access to markets. Statistically significant differences in value elements between service types were also found. As a managerial implication a value gap profile is presented. This Master’s Thesis is part of the MaiSeMa (Industrial Maintenance Services in a Renewing Business Network: Identify, Model and Manage Value) research project where network decision models are created to identify, model and manage the value of maintenance services.

Curving simulation and stability of a creep-controlled wheelset for high speed rail-vehicles

Higher travel speeds of rail vehicles will be possible by developing sophisticated top performance bogies having creep-controlled wheelsets. In this case the torque transmission between the right and the left wheel is realized by an actively controlled creep coupling. To investigate hunting stability and curving capability the linear equations of motion are written in state space notation. Simulation results are obtained with realistic system parameters from industry and various controller gains. The advantage of the „creep-controlled wheelset" is discussed by comparison the simulation results with the dynamic behaviour of the special cases „solid-axle wheelset" and „loose wheelset" (independent rotation of the wheels). The stability is also investigated with a root-locus analysis.

Speed Control of an Autonomous Mobile Robot: Comparison between a PID Control and a Control Using Fuzzy Logic

An Autonomous Mobile Robot battery driven, with two traction wheels and a steering wheel is being developed. This Robot central control is regulated by an IPC, which controls every function of security, steering, positioning localization and driving. Each traction wheel is operated by a DC motor with independent control system. This system is made up of a chopper, an encoder and a microcomputer. The IPC transmits the velocity values and acceleration ramp references to the PIC microcontrollers. As each traction wheel control is independent, it's possible to obtain different speed values for each wheel. This process facilities the direction and drive changes. Two different strategies for speed velocity control were implemented; one works with PID, and the other with fuzzy logic. There were no changes in circuits and feedback control, except for the PIC microcontroller software. Comparing the two different speed control strategies the results were equivalent. However, in relation to the development and implementation of these strategies, the difficulties were bigger to implement the PID control.

Variable structure position control of an industrial robotic manipulator

The use of a robust position controller for a robotic manipulator moving in free space is presented. The aim is to implement in practice a controller that is robust to uncertainties in the model of the system, as well as being inexpensive from a computational point of view. Variable structure theory provides the technique for the design of such controller. The design steps are presented, first from a theoretical perspective and then applied to the control of a two degree-of-freedom manipulator. Simulation results that backed the implementation are presented, followed by the experiments conducted and the results that were obtained. The conclusion is that variable structure control is readily applicable to industrial robots for the robust control of positions.

Experimental study applied to an industrial robot by using variable structure controllers and friction compensation

Control of an industrial robot is mainly a problem of dynamics. It includes non-linearities, uncertainties and external perturbations that should be considered in the design of control laws. In this work, two control strategies based on variable structure controllers (VSC) and a PD control algorithm are compared in relation to the tracking errors considering friction. The controller's performances are evaluated by adding an static friction model. Simulations and experimental results show it is possible to diminish tracking errors by using a model based friction compensation scheme. A SCARA robot is used to illustrate the conclusions of this paper.