bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sifat Fisis dan Mekanis Papan Komposit Berbasis Sabut Kelapa dan Ampas Tebu dengan Variasi Urea Formaldehid
Authors: Haryanti Nida , Faryuni Irfana Diah , Asri Asifa , Hasanuddin Hasanuddin 
Published: December 2020

Penelitian papan komposit berbasis sabut kelapa dan ampas tebu telah berhasil dilakukan. Penelitian ini bertujuan untuk mengetahui dan menganalisis pengaruh komposisi urea formaldehid (UF) terhadap sifat fisis dan mekanis pada papan komposit. Komposisi papan komposit terdiri dari sabut kelapa sebagai core dan ampas tebu sebagai face dan back, dengan UF sebagai perekat. Papan komposit dibuat dengan struktur 3 lapis dengan perbandingan sabut kelapa dan ampas tebu 50:50. Perekat yang digunakan 3 variasi UF, yaitu 6%, 8%, dan 10% dari berat kering partikel masing-masing bahan. Hasil dan metode pengujian papan komposit mengacu pada standarisasi JIS A 5908-2003. Berdasarkan analisis yang telah dilakukan, nilai tertinggi diperoleh pada variasi UF 10% dengan nilai kerapatan sebesar 0,75 g/cm3, kuat pegang sekrup sebesar 59 kg, keteguhan rekat internal sebesar 1,3 kg/cm2, keteguhan lentur sebesar 1.711,26 kg/cm2, keteguhan patah sebesar 26,740 kg/cm2, kadar air sebesar 10,86%. Serta nilai pengembangan tebal sebesar 45,03%. Semakin tinggi kadar perekat maka semakin tinggi nilai kerapatan, keteguhan lentur, keteguhan patah, keteguhan rekat internal, kuat pegang sekrup dan menurunkan nilai kadar air serta pengembangan tebal. Nilai kadar air, kerapatan, dan kuat pegang sekrup memenuhi standar JIS A 5908-2003.
Monitoring Pergerakan Lindi Menggunakan Metode Geolistrik Time-Lapse Di Sekitar Pemukiman Tempat Pembuangan Akhir Batu Layang Pontianak
Authors: Dzulfahmi Dzulfahmi , Ivansyah Okto , Zulfian Zulfian 
Published: December 2020

Telah dilakukan penelitian untuk monitoring pergerakan lindi pada Tempat Pembuangan Akhir (TPA) Batu Layang. Sebaran lindi dimonitor menggunakan metode geolistrik resistivitas konfigurasi Wenner-Schlumberger dengan sampel sebanyak 2 lintasan. Pengambilan data kedua lintasan tersebut dilakukan secara time-lapse, yaitu menggunakan variasi waktu dalam pengambilan data. Variasi waktu tersebut dilakukan setiap satu pekan sekali selama tiga pekan. Berdasarkan analisis penampang resistivitas lindi mempunyai nilai resistivitas kurang dari 10 Ωm. Pergerakan lindi dari pekan pertama hingga pekan ketiga pada lintasan 1 teridentifikasi mulai dari kedalaman 0,75 – 27,5 meter dari permukaan, sedangkan pada lintasan 2 termonitoring dari kedalaman 9 – 27,5 meter dari permukaan. Pada lintasan 1 pergerakan lindi menyebar hingga 116 meter dari awal lintasan, sedangkan pada lintasan 2 menyebar dari 25 – 112 meter dari awal lintasan. Sehingga pergerakan lindi dari TPA Batu Layang menyebar sejauh 334 meter ke arah Barat dari TPA Batu Layang.
Analisis Kekuatan Tarik Serat Bundung (Scirpus grossus) Dengan Variasi Perlakuan Alkali
Authors: Khaidar Hafidh Rayana , Faryuni Irfana Diah , Asri Asifa 
Published: December 2020

Pada penelitian ini telah dilakukan analisis kekuatan tarik serat bundung (Scirpus grossus) yang direndam dalam larutan natrium hidroksida (NaOH). Perendaman serat bundung dalam larutan NaOH divariasikan berdasarkan pengaruh konsentrasi dan pengaruh waktu perendaman. Variasi konsentrasi larutan NaOH yang digunakan adalah 2,5% dan 5%. Sedangkan variasi waktu perendaman adalah 10 menit sampai 150 menit dengan interval waktu 10 menit dan 30 menit. Serat bundung yang telah direndam dengan variasi konsentrasi dan variasi waktu tertentu dijemur di bawah sinar matahari hingga kering. Serat bundung kering dibuat dengan ukuran seragam yaitu (1x0,05x25) cm. Pengujian kekuatan tarik digunakan Universal Testing Machine. Hasil penelitian diperoleh nilai rata-rata kekuatan tarik maksimal serat bundung adalah 120 megapascal pada perendaman NaOH 5% selama 30 menit. Nilai kekuatan tarik ini meningkat hingga 70% dari perlakuan tanpa perendaman NaOH. Hasil pengujian menunjukkan bahwa proses perendaman dalam larutan NaOH dengan konsentrasi dan waktu yang tepat, mampu meningkatkan nilai kekuatan tarik serat bundung. Kata Kunci : Serat bundung, uji mekanik, NaOH, kekuatan tarik
Penentuan Kedalaman Lapisan Gambut Menggunakan Ultra Ground Penetrating Radar untuk Estimasi Cadangan Karbon di Kecamatan Pedamaran
Authors: Kusumaningsih Alvianita Rika Putri , Nugroho Djoko , Ivansyah Okto , Azwar Azrul 
Published: December 2020

Telah dilakukan penelitian tentang estimasi cadangan karbon yang ada di Kecamatan Pedamaran, Ogan Komering Ilir berdasarkan data kedalaman gambut yang diperoleh dari alat ultra ground penetrating radar (GPR). Penelitian ini menggunakan 12 lintasan dengan panjang lintasan berkisar antara 260 m sampai dengan 500 m. Radargram yang diperoleh dari GPR diolah dengan menggunakan perangkat lunak ReflexW untuk mendapatkan nilai kedalaman gambut di lokasi penelitian. Berdasarkan hasil pengolahan data, diperkirakan kedalaman gambut berkisar antara 1,20 m hingga 8,45 m. Dari data kedalaman ini dapat diperkirakan total volume gambut yang ada di lokasi penelitian yaitu . Volume gambut dengan kematangan fibrik sebesar sedangkan volume gambut pada tingkat kematangan hemik sebesar . Hasil penelitian menunjukan bahwa cadangan karbon yang ada dilokasi peelitian diperkirakan sebesar 203,3 juta ton. Kata Kunci: Cadangan Karbon, Kedalaman Gambut, Pedamaran, Ultra GPR.
Transmisi dan Refleksi Gelombang Air yang Merambat Melalui Balok Tenggelam
Authors: Alrizki Azi , Muliadi Muliadi , Azwar Azrul 
Published: December 2020

Telah dilakukan studi tentang transmisi dan refleksi gelombang air yang merambat melalui pemecah gelombang balok tenggelam dengan menganalisis kebergantungan profil spektrumnya terhadap perubahan dimensi balok. Koefisien transmisi dan refleksi diperoleh dengan menyelesaikan hubungan kontinuitas pada batas antar dua kedalaman berbeda. Hasil studi menunjukkan bahwa dalam daerah frekuensi tinggi, gelombang akan diteruskan secara hampir sempurna (hampir tidak ada gelombang yang direfleksikan). Dalam daerah frekuensi rendah, nilai absolut kuadrat dari amplitudo gelombang transmisi dan refleksi berosilasi secara kuasi-periodik yang mengindikasikan bahwa model sederhana dari pemecah gelombang ini hanya berguna secara efektif dalam daerah frekuensi rendah. Kinerja (performance) dari pemecah gelombang balok tenggelam sangat bergantung secara sensitif pada dimensi lebar dan tinggi balok. Sebagai contoh, balok dengan interval lebar 4,0-10,0 m dan tinggi 4,0 m dapat mengurangi 30% dari intensitas gelombang datang dalam rentang frekuensi 0,04-0,24 hertz. Hasil studi ini juga menunjukkan bahwa pemecah gelombang balok tenggelam hanya efektif untuk penggunaan di perairan dangkal.Kata kunci: Gelombang Air, Pemecah Gelombang, Balok Tenggelam, Transmisi, Refleksi.
Identifikasi Struktur Bawah Permukaan di Daerah Pariwisata Ai Sipatn Lotup Kabupaten Sanggau Menggunakan Metode Geolistrik Resistivitas
Authors: Septiansyah Muhammad Riyan , Muliadi Muliadi , Zulfian Zulfian 
Published: December 2020

Penelitian ini telah berhasil mengidentifikasi struktur bawah permukaan di daerah pariwisata Ai Sipatn Lotup Desa Sape Kecamatan Jangkang Kabupaten Sanggau dengan menggunakan metode geolistrik resistivitas konfigurasi Wenner-Schlumberger. Pengambilan data dilakukan pada empat lintasan dengan panjang lintasan 1, lintasan 2, dan lintasan 4 adalah 117 m sedangkan lintasan 3 sepanjang 141 m, dengan spasi elektroda terkecil sebesar 3 m. Hasil penampang resistivitas 2D dari empat lintasan menunjukkan nilai resistivitas pada lintasan 1 adalah 15,1 Ωm – 15379 Ωm, lintasan 2 adalah 15,25 Ωm – 4293 Ωm, lintasan 3 adalah 2,35 Ωm – 1748 Ωm, dan lintasan 4 adalah 1,15 Ωm – 5277 Ωm. Struktur bawah permukaan di daerah penelitian berdasarkan nilai resistivitas penampang 2D diidentifikasi tanah aluvial, pasir lempungan, batupasir, batu kuarsit, dan batu sabak.
Simulasi Gerak Osilasi Model Pegas Bergandeng Menggunakan Metode Runge-Kutta
Authors: Rahmatullah Sigid , Arman Yudha , Apriansyah Apriansyah 
Published: December 2020

Persamaan gerak sistem pegas bergandeng Fay dan Graham (2003) telah diselesaikan secara numerik untuk kemudian dibandingkan dengan hasil perhitungan analitik. Nilai kesebandingan didasarkan pada Symmetric Mean Absolute Percentage Error (SMAPE). Metode numerik utama yang digunakan untuk menyelesaikan persamaan gerak model pegas bergandeng adalah Runge-Kutta Orde Empat dan Runge-Kutta 45 Fehlberg sedangkan metode Leapfrog dan Euler digunakan sebagai metode tambahan uji. Ukuran langkah h yang digunakan adalah 0,05 s. Berdasarkan hasil perhitungan dan nilai SMAPE yang diperoleh, Runge-Kutta 45 Fehlberg menjadi metode numerik dengan tingkat ketelitian yang paling baik diantara berbagai metode numerik yang digunakan pada konfigurasi sistem pegas hasil modifikasi model Fay dan Graham (2003) dengan variasi massa m, arah simpangan x, dan besar konstanta pegas k.Kata Kunci : Pegas, Runge Kutta 45 Fehlberg
Hybrid Gait Planning of A Hexapod Robot
Authors: Wang Ruyi 
Published: December 2020

The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently, which depends on the servos of the robot’s legs, and also the body structure of the robot.This paper compares the tripod gait and the crab-inspired gait for a specific hexapod to move forward and move backward; turn left and turn right and integrates the two gaits to apply them under different conditions. The hexapod has three servos on each legs, thus the freedom level of each leg is three-degree. From the comparative experiment, this two gait patterns are suitable for different turning demands.
Introducing Issue Three
Authors: Elinoff Eli , Gibson Lorena , Trundle Catherine 
Published: December 2020

This issue has taken shape within the context of a global pandemic, and despite these challenges it has provided a welcome space to continue our common intellectual work. Our authors hail from around the globe and have each experienced different aspects of this volatility in different ways at different times. The issue features a special collection entitled Trial by Fire. These essays probe and question the underlying assumptions embedded within the initiatory rites of immersive fieldwork, and the personal consequences and costs that fieldworkers sometimes bear. This issue also contains two articles on the complex ethics of collaboration, an interview with the authors of a graphic ethnography, as well as an extract of this work. Taken together, the contributions to this third issue of Commoning Ethnography continue to address the journal’s core provocations. They explore the way in which ethnography exceeds the boundaries of the Academy and connects scholarly knowledge to other intellectual and artistic modes of knowing and doing. And they probe the complex ethics and politics of ethnographic knowledge production in innovated ways.
Balanço de radiação, energia e fechamento do balanço em uma floresta prístina na Amazônia oriental.
Authors: Ataide Wander Luiz Silva , Oliveira Francisco Assis , Pinto Carlos Alberto Dias 
Published: December 2020

A Floresta Nacional de Caxiuanã, localizada no Estado do Pará, ocupa uma área de 324.060 ha, próxima da baía de Caxiuanã, entre os rios Xingu e Amazonas e compreende aproximadamente 70% do município de Portel e 30% do município de Melgaço. O fluxo de energia foi obtido pelo sistema “Eddy Covariance” localizado a 54 metros de altura. Nota-se uma redução de 10,93% comparando os anos de 2015 (2108,1 mm) e 2016 (2367,8 mm), tendo em vista que a redução da precipitação em determinados sítios é uma consequência das mudanças no balanço de energia e água. O albedo médio do dossel na Flona Caxiuanã foi de 8,5% para ambos os anos avaliados. O fechamento do balanço de energia durante o ano de 2015 e 2016 foi da ordem de 74,83% e 69%, valor este abaixo do que é considerado satisfatório (entre 80 e 90%) como encontrado na literatura. A inclusão do termo (S) na equação melhora substancialmente o fechamento do balanço, principalmente para áreas de florestas primárias devido a quantidade de biomassa. Visando a melhora do fechamento, o fluxo de calor latente foi descartado e então estimado como o resíduo da equação Rn – H – G – S, obtendo um fechamento da ordem de 92,05 e 97,26% para 2015 e 2016.Palavras chave: Eddy covariância, balanço de energia, Caxiuanã, fluxo. Balance of radiation, energy and balance closure in a pristine forest in the eastern Amazon A B S T R A C TThe Caxiuanã National Forest, located in the State of Pará, occupies an area of 324,060 ha, close to Caxiuanã Bay, between the Xingu and Amazonas rivers and comprises approximately 70% of the municipality of Portel and 30% of the municipality of Melgaço. The energy flow was obtained by the “Eddy Covariance” system located 54 meters high. A reduction of 10.93% can be seen comparing the years 2015 (2108.1 mm) and 2016 (2367.8 mm), considering that the reduction of precipitation in certain sites is a consequence of changes in the energy balance and water. The average canopy albedo in Flona Caxiuanã was 8.5% for both years evaluated. The closing of the energy balance during the years 2015 and 2016 was of the order of 74.83% and 69%, a value below what is considered satisfactory (between 80 and 90%) as found in the literature. The inclusion of the term (S) in the equation substantially improves the balance sheet closing, mainly for primary forest areas due to the amount of biomass. In order to improve the closure, the latent heat flow was discarded and then estimated as the residue of the Rn - H - G - S equation, obtaining a closure of the order of 92.05 and 97.26% for 2015 and 2016.Key words: Eddy covariance, energy balance, Caxiuanã, flow.
Análise de não Homogeneidades de Séries de Vazão de Captações de Nascentes na Bacia Hidrográfica do Rio Gramame, PB, Brasil
Authors: Martins Adriana Moura , Filgueira Hamilcar José Almeida , Azevedo Filho Azamor Cirne de , Silva Tarciso Cabral da , Silva Júnior Marcelo Henriques da 
Published: December 2020

A bacia hidrográfica do rio Gramame, no litoral sul paraibano, apresenta diversas nascentes perenes de água com vazões significativas que atendem a comunidades locais para diversos usos. Este trabalho teve como objetivo analisar quatro séries de vazões de captações de nascentes na região sudoeste da bacia e de dados pluviométricos, quanto à sua homogeneidade, entre os anos de 2010 e 2013. A questão motivadora da análise foi a suposta diminuição das vazões de captação das nascentes por consequência da construção de estradas e desmatamentos em áreas do entorno dessas nascentes. Para a análise da homogeneidade das séries, foram empregados testes estatísticos para determinação dos possíveis pontos de ruptura e de verificação da estacionariedade. Foi constatado que houve ruptura em todas as séries de vazões analisadas. Analysis of non-homogeneities of time series of flow in sources in the Gramame River basin, Paraíba State, Brazil A B S T R A C TThe Gramame river basin on the south coast of Paraiba State, has several perennial springs with significant flows that serve local communities for various uses. However, the construction of roads, in areas around the springs, and recent deforestation indicated to have caused the decrease in flows captured from sources in the basin. This work aimed at analyzing four data series of flows captured from sources in the southwestern basin and the rainfall data series searching to verify their homogeneity, between the years 2010 and 2013. To analyze the homogeneity of the series, statistical tests were used to find significant change points and to verify the stationarity. It was found that rupture occurred in all series of flow analyzed.Keywords: flow from springs, hydrometeorological time series, groundwater.
Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete
Authors: Bachtiar Erniati , Mustaan Mustaan , Jumawan Faris , Artayani Meldawati , Tahang Tahang , Rahman Muhammad Junaedy , Setiawan Arman , Ihsan Muhammad 
Published: December 2020

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF
Rehabilitation of the Roof Timber Trusses of a Multiuse Pavilion
Authors: Negrão João H. 
Published: December 2020

This paper describes the rehabilitation procedure of the roof timber structure of a multiuse pavilion in Viseu, Portugal. The roof structure consists of a series of parallel double timber trusses, partially concealed above a polyhedral wooden plank-made ceiling. Recently, the support of one of the trusses failed and another one has been assessed as in a pre-failure condition. Some load-redistribution and the prompt shore of the structure prevented the generalized collapse. The subsequent inspection and assessment led to the conclusion that the primary cause of the collapse was the failure perpendicular to the grain of the solid timber elements inserted between the double rafters and tie-beams. The replacement of the existing with a steel structure, and the repair and reinforcement of the existing wooden trusses, were considered as intervention possibilities. The latter revealed much cheaper, less time-consuming and in line with the international recommendations on rehabilitation works, and was therefore adopted. An innovative solution, consisting of the replacement of the central timber elements in all the supports, resulted in minimum visual impact and improved the load bearing capability beyond its original value. Doi: 10.28991/cej-2020-03091628 Full Text: PDF
Strengthening and Repair of a Precast Reinforced Concrete Residential Building
Authors: Shannag M. Jamal , Higazey Mahmoud 
Published: December 2020

The deterioration or ageing of the existing infrastructures coupled with increased safety requirements necessitate immediate strengthening. Developing long lasting and cost effective repair techniques and materials continue to capture the attention of concrete professionals worldwide. The main purpose of this investigation was to extend the life span of a multi-storey precast reinforced concrete structure built in Riyadh 40 years ago. The condition assessments relied on analytical tools, visual, field and laboratory experiments for core samples collected from the building. The analytical checks of the building revealed considerable deflections of some slabs because of design error. The field and chemical analysis tests performed, confirmed the occurrence of durability defects as a result of poor workmanship during the construction stage. Several state-of-the-art repair techniques and materials were used for enhancing the service life of the structure at a minimum cost. The Repair strategy implemented included, removal of the deteriorated concrete, pouring a bonding agent on the surface of the damage, followed by injecting high strength cementitious grouts, supporting the deflected slabs using I-section steel beams, using cathodic protection to prevent corrosion, strengthening the columns and beams using carbon fiber reinforced polymer (CFRP) sheets, and steel jackets. Doi: 10.28991/cej-2020-03091630 Full Text: PDF
Breve crónica y aplicación de dos criterios de apoyo para la identificación de una clinoptilolita
Authors: Díaz-Guzmán Damián , Legorreta-García Felipe , Pérez-González Nelly Karina , Flores-Zamora María Isabel , Vargas-Ramírez Marissa , Reyes-Cruz Victor Esteban 
Published: December 2020

Los marcos estructurales de la Clinoptilolita y Heulandita son parcialmente idénticos al analizarse con la técnica de difracción de rayos X. Esto ha causado mucha confusión desde la mitad del siglo pasado, por lo que, se han hecho grandes esfuerzos para distinguir entre ambos marcos estructurales. Tan grande ha llegado a ser esta confusión que el subcomité en zeolitas de la Asociación Mineralógica Internacional llegó al punto de declarar una regla especial para la nomenclatura de estas zeolitas. En este trabajo de investigación se introduce una breve crónica sobre estos esfuerzos, así como, la explicación de los principios básicos que aplicamos al buscar reconocer entre ambas. Se realizó la caracterización de una muestra de zeolita natural por medio de las técnicas de difracción de rayos X (DRX), microscopia electrónica de barrido y análisis elemental (MEB – EDS), y fluorescencia de rayos X (FRX) para determinar el tipo de serie de Heulandita usando los criterios de estabilidad térmica, del parámetro y la relación . Este trabajo pretende servir como una pequeña guía que aclare las dudas que comúnmente confunden y, por lo tanto, desmotivan a los iniciados en el estudio de este tipo de zeolitas.
Para além dos números e repetições: aprendizagem dos participantes do Curso de Extensão
Authors: Leite Vania Finholdt Angelo 
Published: December 2020

O artigo analisa as narrativas dos participantes do Curso de Extensão (CE), buscando identificar o que eles apontam do seu processo de aprendizagem. É uma pesquisa de natureza qualitativa, que se insere nos estudos de pesquisa-formação, utilizando a metodologia narrativa na produção de dados. O corpus de análise desse artigo é composto por textos narrativos de dezesseis alunos do CE de uma Universidade Pública do Rio de Janeiro. Temos como referência os estudos de Freire (1978, 1980, 2002,2006), de Ball et al (2012) e de Passegi e Souza (2017). A pesquisa evidenciou que as narrativas dos participantes do CE apontaram: apropriaram de uma proposta de ensino numa perspectiva problematizadora; a relação horizontal entre professor-aluno; o professor media e organiza o ensino; o aluno é considerado um ser pensante, que constrói sua autonomia desde que o professor organize sua aula favorecendo a tomada de decisão, construção de regras e estratégias pessoais.