16 resultados para SEMI-EMPIRICAL THEORY
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
In this dissertation, the theoretical principles governing the molecular modeling were applied for electronic characterization of oligopeptide α3 and its variants (5Q, 7Q)-α3, as well as in the quantum description of the interaction of the aminoglycoside hygromycin B and the 30S subunit of bacterial ribosome. In the first study, the linear and neutral dipeptides which make up the mentioned oligopeptides were modeled and then optimized for a structure of lower potential energy and appropriate dihedral angles. In this case, three subsequent geometric optimization processes, based on classical Newtonian theory, the semi-empirical and density functional theory (DFT), explore the energy landscape of each dipeptide during the search of ideal minimum energy structures. Finally, great conformers were described about its electrostatic potential, ionization energy (amino acids), and frontier molecular orbitals and hopping term. From the hopping terms described in this study, it was possible in subsequent studies to characterize the charge transport propertie of these peptides models. It envisioned a new biosensor technology capable of diagnosing amyloid diseases, related to an accumulation of misshapen proteins, based on the conductivity displayed by proteins of the patient. In a second step of this dissertation, a study carried out by quantum molecular modeling of the interaction energy of an antibiotic ribosomal aminoglicosídico on your receiver. It is known that the hygromycin B (hygB) is an aminoglycoside antibiotic that affects ribosomal translocation by direct interaction with the small subunit of the bacterial ribosome (30S), specifically with nucleotides in helix 44 of the 16S ribosomal RNA (16S rRNA). Due to strong electrostatic character of this connection, it was proposed an energetic investigation of the binding mechanism of this complex using different values of dielectric constants (ε = 0, 4, 10, 20 and 40), which have been widely used to study the electrostatic properties of biomolecules. For this, increasing radii centered on the hygB centroid were measured from the 30S-hygB crystal structure (1HNZ.pdb), and only the individual interaction energy of each enclosed nucleotide was determined for quantum calculations using molecular fractionation with conjugate caps (MFCC) strategy. It was noticed that the dielectric constants underestimated the energies of individual interactions, allowing the convergence state is achieved quickly. But only for ε = 40, the total binding energy of drug-receptor interaction is stabilized at r = 18A, which provided an appropriate binding pocket because it encompassed the main residues that interact more strongly with the hygB - C1403, C1404, G1405, A1493, G1494, U1495, U1498 and C1496. Thus, the dielectric constant ≈ 40 is ideal for the treatment of systems with many electrical charges. By comparing the individual binding energies of 16S rRNA nucleotides with the experimental tests that determine the minimum inhibitory concentration (MIC) of hygB, it is believed that those residues with high binding values generated bacterial resistance to the drug when mutated. With the same reasoning, since those with low interaction energy do not influence effectively the affinity of the hygB in its binding site, there is no loss of effectiveness if they were replaced.
Resumo:
The growing demand in the use of composite materials necessitates a better understanding of its behavior related to many conditions of loading and service, as well as under several ways of connections involved in mechanisms of structural projects. Within these project conditions are highlighted the presence of geometrical discontinuities in the area of cross and longitudinal sections of structural elements and environmental conditions of work like UV radiation, moisture, heat, leading to a decrease in final mechanical response of the material. In this sense, this thesis aims to develop studies detailed (experimental and semi-empirical models) the effects caused by the presence of geometric discontinuity, more specifically, a central hole in the longitudinal section (with reduced cross section) and the influence of accelerated environmental aging on the mechanical properties and fracture mechanism of FGRP composite laminates under the action of uniaxial tensile loads. Studies on morphological behavior and structural degradation of composite laminates are performed by macroscopic and microscopic analysis of affected surfaces, in addition to evaluation by the Measurement technique for mass variation (TMVM). The accelerated environmental aging conditions are simulated by aging chamber. To study the simultaneous influence of aging/geometric discontinuity in the mechanical properties of composite laminates, a semiempirical model is proposed and called IE/FCPM Model. For the stress concentration due to the central hole, an analisys by failures criteria were performed by Average-Stress Criterion (ASC) and Point-Stress Criterion (PSC). Two polymeric composite laminates, manufactured industrially were studied: the first is only reinforced by short mats of fiberglass-E (LM) and the second where the reinforced by glass fiber/E comes in the form of bidirectional fabric (LT). In the conception configurations of laminates the anisotropy is crucial to the final mechanical response of the same. Finally, a comparative study of all parameters was performed for a better understanding of the results. How conclusive study, the characteristics of the final fracture of the laminate under all conditions that they were subjected, were analyzed. These analyzes were made at the macroscopic level (scanner) microscope (optical and scanning electron). At the end of the analyzes, it was observed that the degradation process occurs similarly for each composite researched, however, the LM composite compared to composite LT (configurations LT 0/90º and LT ±45º) proved to be more susceptible to loss of mechanical properties in both regarding with the central hole as well to accelerated environmental aging
Resumo:
Experiments were performed to study the effect of surface properties of a vertical channel heated by a source of thermal radiation to induce air flow through convection. Two channels (solar chimney prototype) were built with glass plates, forming a structure of truncated pyramidal geometry. We considered two surface finishes: transparent and opaque. Each stack was mounted on a base of thermal energy absorber with a central opening for passage of air, and subjected to heating by a radiant source comprises a bank of incandescent bulbs and were performed field tests. Thermocouples were fixed on the bases and on the walls of chimneys and then connected to a data acquisition system in computer. The air flow within the chimney, the speed and temperature were measured using a hot wire anemometer. Five experiments were performed for each stack in which convective flows were recorded with values ranging from 17 m³ / h and 22 m³ / h and air flow velocities ranging from 0.38 m / s and 0.56 m / s for the laboratory tests and air velocities between 0.6 m/s and 1.1m/s and convective airflows between 650 m³/h and 1150 m³/h for the field tests. The test data were compared to those obtained by semi-empirical equations, which are valid for air flow induced into channels and simulated data from 1st Thermodynamics equation. It was found that the chimney with transparent walls induced more intense convective flows than the chimney with matte finish. Based on the results obtained can be proposed for the implementation of prototype to exhaust fumes, mists, gases, vapors, mists and dusts in industrial environments, to help promote ventilation and air renewal in built environments and for drying materials, fruits and seeds
Resumo:
The piles are one of the most important types of solution adopted for the foundation of buildings. They are responsible for transmitting to the soil in deepe r and resistant layers loads from structures. The interaction of the foundation element with the soil is a very important variable, making indispensable your domain in order to determine the strength of the assembly and establish design criteria for each c ase of application of the pile. In this research analyzes were performed f rom experiments load tests for precast concrete piles and inve stigations of soil of type SPT, a study was performed for obtaining the ultimate load capacity of the foundation through methods extrapolation of load - settlement curve , semi - empirical and theoretic . After that, were realized comparisons between the different methods used for two types of soil a granular behavior and other cohesive. For obtaining soil paramet ers to be used i n the methods were established empirical correlations with the standard penetration number (NSPT). The charge - settlement curves of the piles are also analyzed. In the face of established comparisons was indicated the most reliable semiempirical method Déco urt - Quaresma as the most reliable for estimating the tensile strength for granular and cohesive soils. Meanwhile, among the methods studied extrapolation is recommended method of Van der Veen as the most appropriate for predicting the tensile strength.
Resumo:
Trace gases are important to our environment even though their presence comes only by ‘traces’, but their concentrations must be monitored, so any necessary interventions can be done at the right time. There are some lower and upper boundaries which produce nice conditions for our lives and then monitoring trace gases comes as an essential task nowadays to be accomplished by many techniques. One of them is the differential optical absorption spectroscopy (DOAS), which consists mathematically on a regression - the classical method uses least-squares - to retrieve the trace gases concentrations. In order to achieve better results, many works have tried out different techniques instead of the classical approach. Some have tried to preprocess the signals to be analyzed by a denoising procedure - e.g. discrete wavelet transform (DWT). This work presents a semi-empirical study to find out the most suitable DWT family to be used in this denoising. The search seeks among many well-known families the one to better remove the noise, keeping the original signal’s main features, then by decreasing the noise, the residual left after the regression is done decreases too. The analysis take account the wavelet decomposition level, the threshold to be applied on the detail coefficients and how to apply them - hard or soft thresholding. The signals used come from an open and online data base which contains characteristic signals from some trace gases usually studied.
Resumo:
Trace gases are important to our environment even though their presence comes only by ‘traces’, but their concentrations must be monitored, so any necessary interventions can be done at the right time. There are some lower and upper boundaries which produce nice conditions for our lives and then monitoring trace gases comes as an essential task nowadays to be accomplished by many techniques. One of them is the differential optical absorption spectroscopy (DOAS), which consists mathematically on a regression - the classical method uses least-squares - to retrieve the trace gases concentrations. In order to achieve better results, many works have tried out different techniques instead of the classical approach. Some have tried to preprocess the signals to be analyzed by a denoising procedure - e.g. discrete wavelet transform (DWT). This work presents a semi-empirical study to find out the most suitable DWT family to be used in this denoising. The search seeks among many well-known families the one to better remove the noise, keeping the original signal’s main features, then by decreasing the noise, the residual left after the regression is done decreases too. The analysis take account the wavelet decomposition level, the threshold to be applied on the detail coefficients and how to apply them - hard or soft thresholding. The signals used come from an open and online data base which contains characteristic signals from some trace gases usually studied.
Resumo:
This work has as its main purpose to investigate the contribution of supply chain management in order to obtain competitive advantage by companies from the textile industry and from Ceará footwear industry, focusing its analysis mainly in the interorganizational relations (dyadic). For this, the theoretical referential contemplates different explanatory streams of the competitive advantage, detaching the relational perception of the resources theory, as well as, the main presuppositions of the supply chain management which culminates with the development of an analysis sample that runs the empirical study; the one which considers an expanded purpose of the supply chain which includes the government and the abetment institutions as institutional environment representatives. Besides supply chain management consideration as a competitive advantage source, the work also tried to identify other possible competitive advantage sources for the companies of the investigated sectors. It represents a study of multiple interpretive cases, having four cases as a total; meaning two cases in each one of the sectors, which used as a primary data collecting instrument a semi-structured interview schedule. Different methods were used for the data analysis, the content analysis and the constant comparison methods, the analytical procedure originated from the grounded theory research strategy, which were applied the Atlas/ti software recourse. Considering the theoretical referential and the used analysis sample, four basic categories of the work were defined, including its respective proprieties and dimensions: (1) characteristics concerning to the relationship with the supplier; (2) the company relations with the government; (3) the company relations with the abetment institutions and; (4) obtaining sources of competitive advantage. In general, the applied research in the footwear sector revealed that in the relationships of the researched companies related to its suppliers, there is a predominance of the partnership system and the main presuppositions of the supply chain management are applied which contributes for the acquisition of the relational competitive advantage; while in the textile sector, only some of these presuppositions are applied, with little contribution for the relational competitive advantage. The main resource which was accessed by the companies in both sectors through its relationships with the government and the abetment institutions are the tax incentives which, for the footwear companies, contribute for the acquisition of the temporary competitive advantage in relation to the contestants who do not own productive installations in the Northeast region, it also conducts to a competitive parity situation in relation to the contestants who own productive installations in the Northeast region and to the external market contestants; while for the companies of the textile sector, the tax incentives run the companies to a competitive parity situation in relation to its contestants. Furthermore, the investigated companies from the two sectors possess acquisition sources of the competitive advantage which collimate with different explanatory streams (industrial analysis, resources theory, Austrian school and the dynamic capabilities theory), although there is a predominance of the product innovation as a competitive advantage source in both sectors, due to the bond of these with the fashion tendencies
Resumo:
The present inquiry has as main objective to understand the process of formation of the international strategies of the exporting companies of fruits of the RN through the theory of the resource dependence. Aiming at to clarify as the companies they can carry through the process of internationalization through this theory had been study the behavior and economic theories of the process of internationalization of companies. Amongst the economic theories they are distinguished the eclectic paradigm of Dunning (1958), Vernon (1669) through the theory of the cycle of the product and Bucley and Casson (1979) with the theory of the international operations. In the mannering boarding they had been investigated the school of Upsala through Johanson and Valnhe (1977) with the concept of the increasing of the markets and in the distance psychic starts and the interaction of the purchaser-salesman of Hallen and Wiedersheim-Paul (1979). In this perspective it observes main the occured changes in the organization in function of this process, following the rules observed by the gradual ingression in the international market, having as base ways of entrances in the external market used by these companies, in view of the frist phase that the company presents of businesses. Ahead of you analyze of these theories the study searches to analyze the convergence of the concepts proclaimed for the theory of the dependence of resources (PFEFFER; SALANCIK, 1978). and strategies of internationalization of the companies. The research is characterized as qualitative case study which adopts and exploratory and analytical type, retrospective matrix. The adopted strategy is of case study and the unit of analysis consisting of the Finobrasa, pertaining company to the Vicunha Group. The main method of collection of data was halfstructuralized interview allied the documentary research that together had presented an empirical perspective of the internationalization process. The analysis and quarrel of the results understand the description and the interpretation of the one of the information through the technique of analyzes of content. Initially the historical of the exportation of fruits of the Rio Grande do Norte with the focus in the region Açu/Mossoró is presented and after that the information of the Finobrasa are presented as base of the study. The main events are identified that had constituted the phases of the strategical model of the company. It was observed that the dimensions most excellent amongst those proclaimed by the School of Uppsala had been the learning, staffs and the step-starts is sufficiently gifts in the reality of the company, as well as the aspects of strategical alliances since the consolidated relationship of the Vicunha Group create a more solid trajectory in the international market allied the conditions created windows of marked . One understands, therefore, that the investigated process still has base the theoretical theories of the internationalization strategies corroborating for the theoretical convergence of the rules proclaimed for the theory of the dependence of resources.
Resumo:
This work aims to study the associations as mediating the process of social change and its importance for local development. The hypothesis is that associations, but bring dynamism to the smaller cities and improve the living conditions of their members, relegated to the background social sustainability, understood this as a permanent exercise of mobilization and participation in community life. The assumptions of the study are that the practice group has influenced the processes of local development in Brazilian rural municipalities through the mediation of government programs and projects aimed at combating rural poverty require social organization for their achievement. The concept of local development in this work was rescued from studies of political economy and sociology. But the concepts of collective action and partnerships advêem studies of political participation and social development of the theory of alternative or solidarity. The party consisted of an empirical case study conducted with four associations of farmers in the municipality of Portalegre-RN. Why choose qualitative study was used the technique of semi-structured interviews with the chairmen I members of associations and other actors considered essential to understanding the study (religious leaders, local political power and chairman of the union of rural workers), a total of 20 interviews, in addition to the observations of field and documentary research in records of the.ir own organizations. The survey results show that the performance of groups of farmers are key components and determinants for the production I marketing of agricultural products and for boosting the economy, as well as security for minimum levels of citizenship. Yet we are still in a space purpose of social change, which comes to confirm the initial hypothesis of this work
Resumo:
The present study aimed to analyze the vision of tutors from a university hospital about supervised internship in nursing. It is a descriptive nature research with qualitative approach, developed at the University Hospital Onofre Lopes (HUOL), located in Natal/RN. The population was composed of eleven assisting nurses engaged the precentorship of undergraduate course students in nursing, from the Federal University of Rio Grande do Norte (UFRN). For the empirical research, conducted in the period from September to November 2013, the semi-structured interview involving questions directed to the stage was used, as advocate the national curriculum guidelines, as regards this curricular component. With the consent of the institution where the study has been developed and approved by the Research Ethics Committee of UFRN, as n° 17800613.9.0000.5537, besides CAAE signing an informed consent by participants. The analysis of the information was held from the analysis of content, thematic mode. Thereby four categories were defined a priori, namely: the supervised internship in the vision of nurses; To be preceptor; The internship concerned: contributions and difficulties; Do the institutional actors communicate? The results indicate that in the view of the supervised internship preceptors is a sine qua non for the training of nurses, considering that it prepares for professional life. Besides being a moment conducive to the exercise of management and a greater rapprochement between theory and practice, stimulates the preceptor to upgrade to better exercise the function and also provides an exchange of knowledge between students and tutors, thus contributing to optimize the service. Nevertheless, the respondents indicate the existence of a distancing and little communication with the academic institution. In summary, it is realized that the nurses understand the importance of its function of tutors and supervised stage for vocational training. It is necessary, however, to reflect on the paths to be pinched in the confrontation of difficulties in this process, especially as regards the teaching/service relationship, which, while remaining at a distance, strengthens the existing dichotomy between theory and practice
Resumo:
In northeastern semiarid, seasonality on precipitation temporal distribution, high intensity storm events and inadequate management of native vegetation can promote soil erosion. Vegetation removal causes soil surface exposure, reduces soil water storage capacity and can be the source degradation processes. In this context, this approach aims to analyze water and soil erosion processes on a 250 m2 undisturbed experimental plot with native vegetation, slope 2.5% by using 2006 and 2007 monitoring data. The site was instrumented to monitor rainfall, overland flow runoff and erosion by using a 5 m³ tank downstream the plot. Soil erosion monitoring was made by transported sediment and organic matter collection after each event. Field infiltration experiments were made at 16 points randomly distributed within the plot area by using a constant head infiltrometer during drought and rainy seasons, respectively. Infiltration data revealed high spatial and temporal variability. It was observed that during the beginning of the rainy period, 77% of the events showed runoff coefficient less than 0.05. As the rainy season began, soil water increase produced annual species germination. High intensity storms resulted in runoff coefficients varying between 0.33 and 0.42. Once the annual species was established, it was observed that approximately 39% of the events produced no runoff, which reflects an increase on soil water retention capacity caused by the vegetation. A gradual runoff reduction during the rainy season emphasizes the effect of vegetative density increase. Soil erosion observed data allowed to fit an empirical relationship involving soil loss and precipitation height, which was used to analyze the plot installation impact on soil erosion. Observed soil loss in 2006 and 2007 was 230 Kg/ha and 54 Kg/ha, respectively
Resumo:
In distance learning degree in Chemistry in full of the Secretária de Educação a distância da Universidade Federal do Rio Grande do Norte (SEDIS / UFRN). The teacher-tutor to establish the experimental subjects closer relationships with students, mediating the pedagogical actions that develop in the distance learning course, with a view to achieving the principles of autonomy and learning, contributing to the creation of learning environments collaborative, guided by affection.The article presents the results of an empirical research on affectivity in practice this tutorial experimental classes in higher distance education in the full degree course in Chemistry Polo Currais Novos/ RN, held between 2009 and 2010. The study is based on qualitative methodology, whose data were collected through questionnaires and semi-structured interviews with 48 (forty eight) students involved in distance learning courses and selected in order to compose a group of subjects who showed variability, as guidelines that guide the sampling procedures in qualitative research. The results, based on category theory and empirical analysis of data from the interviews were supplemented by information obtained from participant observation which also served to guide the data collection of the corpus of this work. With the results we understand that there is clarity about what characterizes a loving relationship between those involved in the process of teaching and learning in experimental classes in high school chemistry Distance Education. Furthermore, it was also clear that the communication process in dialogic teaching and learning in higher distance education in chemistry at the trial need to mark out in balanced affective attitudes, the experimental error that value and respect the many possible construction of knowledge by movements social interaction of individual and collective
Resumo:
In distance learning degree in Chemistry in full of the Secretária de Educação a distância da Universidade Federal do Rio Grande do Norte (SEDIS / UFRN). The teacher-tutor to establish the experimental subjects closer relationships with students, mediating the pedagogical actions that develop in the distance learning course, with a view to achieving the principles of autonomy and learning, contributing to the creation of learning environments collaborative, guided by affection.The article presents the results of an empirical research on affectivity in practice this tutorial experimental classes in higher distance education in the full degree course in Chemistry Polo Currais Novos/ RN, held between 2009 and 2010. The study is based on qualitative methodology, whose data were collected through questionnaires and semi-structured interviews with 48 (forty eight) students involved in distance learning courses and selected in order to compose a group of subjects who showed variability, as guidelines that guide the sampling procedures in qualitative research. The results, based on category theory and empirical analysis of data from the interviews were supplemented by information obtained from participant observation which also served to guide the data collection of the corpus of this work. With the results we understand that there is clarity about what characterizes a loving relationship between those involved in the process of teaching and learning in experimental classes in high school chemistry Distance Education. Furthermore, it was also clear that the communication process in dialogic teaching and learning in higher distance education in chemistry at the trial need to mark out in balanced affective attitudes, the experimental error that value and respect the many possible construction of knowledge by movements social interaction of individual and collective
Resumo:
Brazil lives a time of experimentation and maturity as it pertains to managing the use of water, which comes institutionalising increasingly social participation. In Rio Grande do Norte, since 1997, the government has been developing actions accordingly, through the State Department of Water Resources, which has implemented a programme of adutoras within the State and created Water Users Associations, in the installation of dessalinizadores for places where the Adutora was not necessary or not yet arrived, so that should be managed by communities through associations of users. Since 2003, Civil Society Organisations - CSOs come through ASA - Articulation in the Semi-arid Brazilian, implementing the P1MC - Program of Training and Mobilization for Social Living with the Semi-Arid (One Million Rural Cisternas), in its third year of implementation in Rio Grande do Norte, in the spirit of working together with the semi arid. In the municipality of Serrinha / RN which incorporates the Semi-arid region, we find in the rural community of Pendêcias dos Emídios the experience of the State and Civil Society, which referred to a discussion about the environmental sustainability of these initiatives. The general objective of this work is to examine the strategies for participatory management in the use and access to water in the community of Pendêcias dos Emídios of the municipality of Serrinha / RN, to understand how those experiences can contribute to environmental sustainability. The methodology used envolvel bibliographic research in categories involving each article, the analysis of the terms of reference of each strategy as part of the documentary research, the application forms covering 40 families benefited, and interviews based on comprehensive analysis of the speech. This study is divided into 02 articles, where the first is a discussion held on collective action and environmental sustainability, and the second is held a discussion about the sustainability of the initiatives underway to access water. The results of the discussion held on 02 articles that had their empirical built from the experience of the Commonwealth of Pendências dos Emídios revealed how far will the ability of the State to promote collective action and the limitations of the perception of sustainability that permeates these initiatives in the search for democratic access to water in semi-arid
Resumo:
This work has as its main purpose to investigate the contribution of supply chain management in order to obtain competitive advantage by companies from the textile industry and from Ceará footwear industry, focusing its analysis mainly in the interorganizational relations (dyadic). For this, the theoretical referential contemplates different explanatory streams of the competitive advantage, detaching the relational perception of the resources theory, as well as, the main presuppositions of the supply chain management which culminates with the development of an analysis sample that runs the empirical study; the one which considers an expanded purpose of the supply chain which includes the government and the abetment institutions as institutional environment representatives. Besides supply chain management consideration as a competitive advantage source, the work also tried to identify other possible competitive advantage sources for the companies of the investigated sectors. It represents a study of multiple interpretive cases, having four cases as a total; meaning two cases in each one of the sectors, which used as a primary data collecting instrument a semi-structured interview schedule. Different methods were used for the data analysis, the content analysis and the constant comparison methods, the analytical procedure originated from the grounded theory research strategy, which were applied the Atlas/ti software recourse. Considering the theoretical referential and the used analysis sample, four basic categories of the work were defined, including its respective proprieties and dimensions: (1) characteristics concerning to the relationship with the supplier; (2) the company relations with the government; (3) the company relations with the abetment institutions and; (4) obtaining sources of competitive advantage. In general, the applied research in the footwear sector revealed that in the relationships of the researched companies related to its suppliers, there is a predominance of the partnership system and the main presuppositions of the supply chain management are applied which contributes for the acquisition of the relational competitive advantage; while in the textile sector, only some of these presuppositions are applied, with little contribution for the relational competitive advantage. The main resource which was accessed by the companies in both sectors through its relationships with the government and the abetment institutions are the tax incentives which, for the footwear companies, contribute for the acquisition of the temporary competitive advantage in relation to the contestants who do not own productive installations in the Northeast region, it also conducts to a competitive parity situation in relation to the contestants who own productive installations in the Northeast region and to the external market contestants; while for the companies of the textile sector, the tax incentives run the companies to a competitive parity situation in relation to its contestants. Furthermore, the investigated companies from the two sectors possess acquisition sources of the competitive advantage which collimate with different explanatory streams (industrial analysis, resources theory, Austrian school and the dynamic capabilities theory), although there is a predominance of the product innovation as a competitive advantage source in both sectors, due to the bond of these with the fashion tendencies