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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 11 to 20 of 21 (0.008 seconds)| 11 |
Estudo dos efeitos da adiÃÃo de ZnO e Nb2O5 nas propriedades dielÃtricas da matriz cerÃmicas BaBi4Ti4O15 (BBT) e suas aplicaÃÃes em antenas / Study of the Effects of Addition of ZnO and Nb2O5 in the dielectric properties of the Matrix Ceramics Babi4ti4o15 (BBT) and its Applications in AntennasPaulo Maria de Oliveira e Silva 11 October 2013 (has links)
nÃo hà / Com o rÃpido crescimento das indÃstrias de telecomunicaÃÃes criou-se uma forte necessidade por materiais cerÃmicos para aplicaÃÃes em micro-ondas. Devendo estes materiais apresentar alta permissividade dielÃtrica (εr), elevado fator de qualidade (Q), boa estabilidade tÃrmica (τf Â10 ppm/ÂC) e baixo custo. Com a invenÃÃo de telefones celulares portÃteis, o campo da comunicaÃÃo sem fio passou por um crescimento inovador nas Ãltimas dÃcadas. O sucesso da terceira geraÃÃo (3G) dos serviÃos de comunicaÃÃo de telefonia celular, motiva o desenvolvimento de banda larga de quarta geraÃÃo (4G) de telefones celulares e outros produtos e serviÃos sem fio, como por exemplo, o Bluetooth. Este trabalho consiste no desenvolvimento e caracterizaÃÃo da cerÃmica de titanato de bÃrio-bismuto (BaBi4Ti4O15) com adiÃÃo de Ãxido de niÃbio (Nb2O5) ou Ãxido de zinco (ZnO), visando a diminuiÃÃo da temperatura de sinterizaÃÃo e possivelmente melhorar a densificaÃÃo, e posteriormente, verificar as modificaÃÃes ocorridas nas propriedades do material, como por exemplo, o coeficiente de temperatura da frequÃncia ressonante (τf). As sÃries cerÃmicas foram produzidas usando a reaÃÃo no estado sÃlido, com o uso de moagem mecÃnica de alta energia e tratamento tÃrmico. A caracterizaÃÃo estrutural foi realizada com base na Microscopia EletrÃnica de Varredura (MEV) e Picnometria. As densidades relativas das amostras adicionadas com (ZnO) a de maior concentraÃÃo teve valor de 77% enquanto que o BBT puro o valor foi de 56%. As densidades relativas das amostras adicionadas com (Nb2O5) a de maior concentraÃÃo teve valor de 61% em relaÃÃo ao BBT puro. Foram realizados experimentos para avaliaÃÃo do comportamento elÃtrico e dielÃtrico das amostras, na faixa de Micro-ondas e RadiofrequÃncia (temperatura ambiente e com variaÃÃo de temperatura). Por fim, o material foi testado como uma DRA, e posteriormente os resultados obtidos foram simulados atravÃs do programa HFSS. As caracterÃsticas da DRA da cerÃmica pura sÃo 1,12dBi de ganho e 32,51% de eficiÃncia. A DRA que foi adicionada com 2% de (ZnO) apresentou ganho de 1,16dBi com 33,96% de eficiÃncia, enquanto a que foi adicionada com 5% de (Nb2O5) apresentou 1,41dBi de ganho com 42,21% de eficiÃncia. / With the rapid growth of the telecommunications industry created a strong need for ceramic materials for applications in microwave. These materials should exhibit high dielectric permittivity (εr), high quality factor (Q), good thermal stability (τf Â10 ppm/ÂC) and low cost. With the invention of mobile phones, the field of wireless communication has undergone a revolutionary growth in recent decades. The success of the third generation (3G) services in mobile communication, motivates the development of broadband fourth generation (4G) of mobile phones and other wireless products and services, such as Bluetooth. Nowadays it is well known the use of tablets, which are increasingly gaining market and encouraging the development of new technologies to improve the flow of information. This work involves the development and characterization of the barium bismuth titanate ceramic, (BaBi4Ti4O15) with addition of niobium oxide (Nb2O5) or zinc oxide (ZnO) in order to decrease the sintering temperature and possibly improve the densification and subsequently check the modifications on material properties, such as the temperature coefficient of resonant frequency (τf). The series ceramics were produced using the solid state reaction with the use of high energy mechanical milling and heat treatment. The structural characterization was performed based on Scanning Electron Microscopy (SEM) and Measurement by Pycnometer. The relative densities of the samples with added (ZnO) had the highest concentration value of 77% pure BBT while the value was 56%. The relative densities of the samples spiked with (Nb2O5) had the highest concentration value of 61% compared to pure BBT. Experiments were conducted to evaluate the electrical and dielectric behavior of the samples in the range of Microwave and Radio Frequency (temperature and temperature variation). Finally, the material was tested as a DRA, and then the results were simulated using the HFSS program. The characteristics of the pure ceramic DRA are 1,12dBi gain and 32,51% efficiency. The DRA added with 2% (ZnO ) showed 1.16dBi gain with 33,96% efficiency , while the one that was added with 5% (Nb2O5) showed gain of 1.41dBi with 42,21% efficiency.
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Evidências de validade concorrente entre o BBT-Br e a BFP: um estudo com universitários / Evidence of concurrent validity between the BBT-Br and the BFP: a study with undergraduate students.Shimada, Milena 18 January 2016 (has links)
A intervenção em Orientação Profissional e de Carreira objetiva promover a autonomia e autoconhecimento dos indivíduos, auxiliando na construção de seus projetos de vida. Dentre as técnicas que podem ser utilizadas pelos psicólogos nos processos de intervenção, destaca-se o Teste de Fotos de Profissões - BBT-Br, um teste projetivo que avalia interesses vocacionais. A fim de reunir evidência empírica das hipóteses interpretativas do BBT, este estudo explorou as correlações entre interesses vocacionais e traços de personalidade, avaliados por meio da Bateria Fatorial de Personalidade - BFP. Ainda, objetivou-se ampliar os dados do BBT-Br para estudantes do Ensino Superior, uma vez que a maioria dos estudos com este instrumento centra-se em adolescentes do Ensino Médio. Participaram da pesquisa 906 universitários, de ambos os sexos, com idade média de 23.38 anos (D.P. = 5.18), procedentes de instituições públicas e privadas. Para fins de comparação, foram também consultados protocolos dos estudos normativos do BBT-Br (n = 595 universitários), bem como de uma amostra de 497 adolescentes do 3o ano do Ensino Médio. Os instrumentos foram aplicados coletivamente em sala de aula, a saber: (a) questionário socioprofissional; (b) BBT-Br, em formato de aplicativo para tablets desenvolvido nesse estudo, para uso específico em pesquisa; e (c) BFP. Os dados obtidos por meio do BBT-Br foram exportados para banco de dados, enquanto os referentes ao questionário e à BFP foram digitados em programa computacional. Os resultados dos instrumentos de avaliação psicológica foram sistematizados de acordo com seus referenciais técnicos. Os resultados do BBT-Br foram analisados de forma descritiva e comparados, por meio de testes t de Student, com os referenciais normativos disponíveis e com resultados de uma amostra de estudantes do Ensino Médio. A precisão do BBT-Br foi estimada por sua consistência interna (Alfa de Cronbach). A análise da relação entre as variáveis do BBT-Br e da BFP foi realizada por meio de correlação de Pearson. Já a comparação dos resultados do BBT-Br em função das diferentes áreas do conhecimento foi realizada por meio de análises de variância (ANOVA One Way). Os resultados evidenciaram correlações significativas entre as variáveis do BBT-Br e da BFP, de .25 a .41, especificamente entre: o radical Z, a faceta Interesses por novas ideias e o fator Abertura; o radical V e a faceta Competência do fator Realização; o radical G e a faceta Interesses por novas ideias; o radical O e facetas Comunicação, Dinamismo e o fator Extroversão. Os achados são condizentes com as premissas teóricas do BBT-Br, bem como a literatura científica sobre interesses profissionais e personalidade. Os resultados do BBT-Br apontaram distinções nos índices de produtividade e estruturas de inclinação em função do sexo, escolaridade e área do conhecimento. A precisão variou entre .59 e .85, indicando índices razoáveis de fidedignidade para as duas formas do BBT-Br. As evidências deste estudo, de modo geral, corroboram os pressupostos teóricos dos radicais de inclinação do BBT-Br, por meio da relação com os fatores de personalidade. Ainda, apontam que este instrumento projetivo pareceu avaliar adequadamente os interesses profissionais da amostra de universitários, reforçando indícios de sua utilidade em intervenções de carreira. / Vocational guidance interventions aim to promote individuals\' autonomy and selfknowledge, helping them to construct their life projects. Among the techniques available for psychologists to use in these intervention processes, we highlight the Berufsbilder Test - BBT-Br, a projective test that assess vocational interests. In order to gather empirical evidence of the BBT\'s interpretative hypotheses, this study\'s objective was to explore correlations between vocational interests and personality traits assessed through Bateria Fatorial de Personalidade - BFP. Another objective was to use BBT-Br with college students, since most studies using this instrument focus on adolescents in high school. A total of 906 college students, both sexes, aged 23.38 years old on average (SD = 5.18) from both public and private colleges, were assessed. Protocols of BBT-Br normative studies were also consulted to make comparisons (n = 595 college students), as well as a sample of 497 adolescents attending the 3rd year of high school. The instruments were collectively applied in a classroom, namely: (a) socio-professional questionnaire; (b) BBT-Br, in an app format for tablets specifically to be used in research was developed for this study; and (c) BFP. Data obtained trough BBT-Br were exported to a database while those concerning the BFP questionnaire were entered in a computer program. The results from the psychological assessment instruments were systematized according to their technical frameworks. The BBT-Br results were descriptively analyzed and compared using Student t test with the normative references available and with results from a sample of high school students. Accuracy of BBT-Br was estimated using its internal consistency (Cronbach\'s alpha). Analysis of relationship between the variables of BBTBr and BFP was performed using Pearsons correlations, while the comparison of BBT-Br results regarding the different fields of knowledge was conducted using variance analysis (ANOVA One Way). The results show significant correlations between the variables of both BBT-Br and BFP, from .25 to .41, specifically between: Z radical, Interest for new ideas facet and Openness; V and Competence facet of Conscientiousness factor; G and Interest for new ideas facet; O and Communication and Dynamism facets, and Extraversion factor. These findings are in agreement with the theoretical assumptions of BBT-Br, as well as with the scientific literature addressing vocational interests and personality. The results from BBT-Br indicated distinctions in the indexes of productivity and interest structures based on sex, education, and field of knowledge. Accuracy ranged from .59 and .85, indicating reasonable indexes of reliability for both formats of BBT-Br. In general, evidence from this study corroborates the theoretical assumptions of interest radicals of BBT-Br through relationship with personality factors. The results also indicate this projective instrument properly assessed the vocational interests of the sample of college students, reinforcing its usefulness in career interventions.
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Evidências de validade concorrente entre o BBT-Br e a BFP: um estudo com universitários / Evidence of concurrent validity between the BBT-Br and the BFP: a study with undergraduate students.Milena Shimada 18 January 2016 (has links)
A intervenção em Orientação Profissional e de Carreira objetiva promover a autonomia e autoconhecimento dos indivíduos, auxiliando na construção de seus projetos de vida. Dentre as técnicas que podem ser utilizadas pelos psicólogos nos processos de intervenção, destaca-se o Teste de Fotos de Profissões - BBT-Br, um teste projetivo que avalia interesses vocacionais. A fim de reunir evidência empírica das hipóteses interpretativas do BBT, este estudo explorou as correlações entre interesses vocacionais e traços de personalidade, avaliados por meio da Bateria Fatorial de Personalidade - BFP. Ainda, objetivou-se ampliar os dados do BBT-Br para estudantes do Ensino Superior, uma vez que a maioria dos estudos com este instrumento centra-se em adolescentes do Ensino Médio. Participaram da pesquisa 906 universitários, de ambos os sexos, com idade média de 23.38 anos (D.P. = 5.18), procedentes de instituições públicas e privadas. Para fins de comparação, foram também consultados protocolos dos estudos normativos do BBT-Br (n = 595 universitários), bem como de uma amostra de 497 adolescentes do 3o ano do Ensino Médio. Os instrumentos foram aplicados coletivamente em sala de aula, a saber: (a) questionário socioprofissional; (b) BBT-Br, em formato de aplicativo para tablets desenvolvido nesse estudo, para uso específico em pesquisa; e (c) BFP. Os dados obtidos por meio do BBT-Br foram exportados para banco de dados, enquanto os referentes ao questionário e à BFP foram digitados em programa computacional. Os resultados dos instrumentos de avaliação psicológica foram sistematizados de acordo com seus referenciais técnicos. Os resultados do BBT-Br foram analisados de forma descritiva e comparados, por meio de testes t de Student, com os referenciais normativos disponíveis e com resultados de uma amostra de estudantes do Ensino Médio. A precisão do BBT-Br foi estimada por sua consistência interna (Alfa de Cronbach). A análise da relação entre as variáveis do BBT-Br e da BFP foi realizada por meio de correlação de Pearson. Já a comparação dos resultados do BBT-Br em função das diferentes áreas do conhecimento foi realizada por meio de análises de variância (ANOVA One Way). Os resultados evidenciaram correlações significativas entre as variáveis do BBT-Br e da BFP, de .25 a .41, especificamente entre: o radical Z, a faceta Interesses por novas ideias e o fator Abertura; o radical V e a faceta Competência do fator Realização; o radical G e a faceta Interesses por novas ideias; o radical O e facetas Comunicação, Dinamismo e o fator Extroversão. Os achados são condizentes com as premissas teóricas do BBT-Br, bem como a literatura científica sobre interesses profissionais e personalidade. Os resultados do BBT-Br apontaram distinções nos índices de produtividade e estruturas de inclinação em função do sexo, escolaridade e área do conhecimento. A precisão variou entre .59 e .85, indicando índices razoáveis de fidedignidade para as duas formas do BBT-Br. As evidências deste estudo, de modo geral, corroboram os pressupostos teóricos dos radicais de inclinação do BBT-Br, por meio da relação com os fatores de personalidade. Ainda, apontam que este instrumento projetivo pareceu avaliar adequadamente os interesses profissionais da amostra de universitários, reforçando indícios de sua utilidade em intervenções de carreira. / Vocational guidance interventions aim to promote individuals\' autonomy and selfknowledge, helping them to construct their life projects. Among the techniques available for psychologists to use in these intervention processes, we highlight the Berufsbilder Test - BBT-Br, a projective test that assess vocational interests. In order to gather empirical evidence of the BBT\'s interpretative hypotheses, this study\'s objective was to explore correlations between vocational interests and personality traits assessed through Bateria Fatorial de Personalidade - BFP. Another objective was to use BBT-Br with college students, since most studies using this instrument focus on adolescents in high school. A total of 906 college students, both sexes, aged 23.38 years old on average (SD = 5.18) from both public and private colleges, were assessed. Protocols of BBT-Br normative studies were also consulted to make comparisons (n = 595 college students), as well as a sample of 497 adolescents attending the 3rd year of high school. The instruments were collectively applied in a classroom, namely: (a) socio-professional questionnaire; (b) BBT-Br, in an app format for tablets specifically to be used in research was developed for this study; and (c) BFP. Data obtained trough BBT-Br were exported to a database while those concerning the BFP questionnaire were entered in a computer program. The results from the psychological assessment instruments were systematized according to their technical frameworks. The BBT-Br results were descriptively analyzed and compared using Student t test with the normative references available and with results from a sample of high school students. Accuracy of BBT-Br was estimated using its internal consistency (Cronbach\'s alpha). Analysis of relationship between the variables of BBTBr and BFP was performed using Pearsons correlations, while the comparison of BBT-Br results regarding the different fields of knowledge was conducted using variance analysis (ANOVA One Way). The results show significant correlations between the variables of both BBT-Br and BFP, from .25 to .41, specifically between: Z radical, Interest for new ideas facet and Openness; V and Competence facet of Conscientiousness factor; G and Interest for new ideas facet; O and Communication and Dynamism facets, and Extraversion factor. These findings are in agreement with the theoretical assumptions of BBT-Br, as well as with the scientific literature addressing vocational interests and personality. The results from BBT-Br indicated distinctions in the indexes of productivity and interest structures based on sex, education, and field of knowledge. Accuracy ranged from .59 and .85, indicating reasonable indexes of reliability for both formats of BBT-Br. In general, evidence from this study corroborates the theoretical assumptions of interest radicals of BBT-Br through relationship with personality factors. The results also indicate this projective instrument properly assessed the vocational interests of the sample of college students, reinforcing its usefulness in career interventions.
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Impact of Binaural Beat Technology on Vigilance Task Performance, Psychological Stress and Mental WorkloadShoda, Elizabeth Ann 08 November 2013 (has links)
No description available.
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Organic solar cells : novel materials, charge transport and plasmonic studiesEbenhoch, Bernd January 2015 (has links)
Organic solar cells have great potential for cost-effective and large area electricity production, but their applicability is limited by the relatively low efficiency. In this dissertation I report investigations of novel materials and the underlying principles of organic solar cells, carried out at the University of St Andrews between 2011 and 2015. Key results of this investigation: • The charge carrier mobility of organic semiconductors in the active layer of polymer solar cells has a rather small influence on the power conversion efficiency. Cooling solar cells of the polymer:fullerene blend PTB7:PC₇₁BM from room temperature to 77 K decreased the hole mobility by a factor of thousand but the device efficiency only halved. • Subphthalocyanine molecules, which are commonly used as electron donor materials in vacuum-deposited active layers of organic solar cells, can, by a slight structural modification, also be used as efficient electron acceptor materials in solution-deposited active layers. Additionally these acceptors offer, compared to standard fullerene acceptors,advantages of a stronger light absorption at the peak of the solar spectrum. • A low band-gap polymer donor material requires a careful selection of the acceptor material in order to achieve efficient charge separation and a maximum open circuit voltage. • Metal structures in nanometer-size can efficiently enhance the electric field and light absorption in organic semiconductors by plasmonic resonance. The fluorescence of a P3HT polymer film above silver nanowires, separated by PEDOT:PSS, increased by factor of two. This could be clearly assigned to an enhanced absorption as the radiative transition of P3HT was identical beside the nanowires. • The use of a processing additive in the casting solution for the active layer of organic solar cells of PTB7:PC₇₁BM strongly influences the morphology, which leads not only to an optimum of charge separation but also to optimal charge collection.
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Design Of Smart Toothbrush : For cause-and-effect studiesIssa, Yosur, Gauffin, Johan January 2021 (has links)
Genom åren har det funnits en marknad för att förhindra samt öka chanserna att bli gravid. Individer har vänt sig till appar för hjälp, där syftet har varit att öka individenskunskap om när fertilitetfönstret sker under cyklens gång. Fertilitetfönstret kan upptäckas genom olika metoder. Under studiens gång las fokus på att bygga uppförståelse för basal kroppstemperatur. Därefter vidareutvecklades en smart tandborste integrerat med en temperature sensor, med syftet att kunna identifiera korrelation mellan basal kroppstemperatur och ägglossning. Syftet var att undersöka om en smart tandborste integrerat med en temperatur sensor, kunde identifiera potential ägglossning. Identifiering kunde skapas genom finna den potentiella sambandet mellan basal kroppstemperatur och ägglossning. Produktenskapades genom användning av maskininlärningsteknik. Det uppsatta syftet svaradepå forskningsfrågorna; kan maskininlärningstekniker stödja förutsägelse av ägglossning från basal kroppstemperatur (förkortning Eng: BBT) med en smart tandborste och hur ska en temperatursensor integreras i en elektrisk tandborste? Fördjupningsarbetet delades in i tre delar, undersökning av basal kroppstemperatur, data analys och produktdesign. En litteraturstudie utfördes av alla delar där undersökning om vilka likheter kroppstemperatur har mot basal kroppstemperatur, hur data analys kan användas till att upptäcka ägglossning med basal kroppstemperatur, och hur en produkt kan bäst designas för målen i arbetet. Före påbörjandet av examensarbete, samlades 11 individers basal kroppstemperatur in. Den valda metoden för att vidare analysera den givna data kallas för k-means clustering. Underdataanalysen ändrades antalet grupperingar för att finna grupper där potentiell ägglossning kunde ha uppstått. Validering av dessa potentiella grupper gjordes med data hämtat från hemsidan my monthly cycle. För produktutveckling användes flera olika tekniker, för att vägleda samt analysera produkten från olika perspektiv. Genom noggrann mätning av kroppstemperatur kunde den basala kroppstemperaturen uppskattas, med en okänd noggrannhet. Kluster av den för-insamlade dataformades och visade att vissa grupper kunde tolkas ha potential till ägglossning. Dessa potentiella grupper kunde valideras till att ha majoriteten av ägglossningsdata tilldelat till dem när färre grupperingar gjordes. En optimal prototyp skapades med hänsyn på hållbarhet, och bekvämlighet, både för bruk och minskning av sysslor. Sammanfattningsvis visade användning av klusteranalys ha en potentiell möjlighetför att kunna detektera ägglossning hos kroppstemperatur data som samlas in med en smart tandborste. För framtida forskning bör en tandborstdesign först skapas för att samla in basal kroppstemperatur data, där följaktligen blir att använda den insamlade datan till data analysen
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3D Pen BBT Side Mold M02D RC02 in GoBar DeckHemphill, Bill 07 June 2022 (has links)
https://dc.etsu.edu/oer-guitars-images-complete/1000/thumbnail.jpg
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3D Render BBT Side Mold M02D RC02 in GoBar DeckHemphill, Bill 07 June 2022 (has links)
https://dc.etsu.edu/oer-guitars-images-complete/1001/thumbnail.jpg
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BBT Side Mold AssyHemphill, Bill 07 June 2022 (has links)
This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass data, and layer names (formatted for AXYZ's ToolPath CAM software).
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BBT Acoustic Alternative Top Bracing CADD Data Set-NoRev-2022Jun28Hemphill, Bill 22 July 2022 (has links)
This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are (a) a one-piece base for the standard kit's (Martin-style) bracing, (b) 277 Ladder-style bracing, and (c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.
The CADD data set for each of the three (3) top bracing designs includes (a) a nominal 24" x 18" x 3mm (0.118") Baltic birch plywood laser layout of (1) the one-piece base with slots, (2) pre-radiused and pre-scalloped vertical braces with tabs to ensure proper orientation and alignment, and (3) various gages and jigs and (b) a nominal 15" x 20" marking template.
The 'provided as is" CADD data is formatted for use on a Universal Laser Systems (ULS) laser cutter digital (CNC) device. Each CADD drawing is also provided in two (2) formats: Autodesk AutoCAD 2007 .DWG and .DXF R12. Users should modify and adapt the CADD data as required to fit their equipment. This CADD data set is released and distributed under a Creative Commons license; users are also encouraged to make changes o the data and share (with attribution) their designs with the worldwide acoustic guitar building community.
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