bluuebunny/crossref_metadata_2025 huggingface dataset:
PENGEMBANGAN POCKET BOOK BERBANTUAN GEOGEBRA DENGAN PENDEKATAN PMRI (PENDIDIKAN MATEMATIKA REALISTIK INDONESIA) PADA MATERI SEGIEMPAT KELAS VII SMP/MTs.
Authors: Istianah Istianah
Published: October 2017

Dari hasil observasi di lapangan media pembelajaran matematika yang digunakan berupa buku paket dan penyajian materi dalam buku paket didominasi oleh penulis sehingga siswa bersikap pasif memahami apa yang dijelaskan penulis untuk itu pengembangan media pembelajaran berbentuk pocket book berbantuan GeoGebra dengan pendekatan PMRI sangat diperlukan. Penelitian pengembangan ini dilakukan dengan menggunakan model 3-D yang diadaptasi dari model 4-D yaitu melalui tahap pendefinisian (Define), perencanaan (Design), dan pengembangan (Develop). Desain penelitian yang digunakan adalah quasi eksperiment. Hasil penelitian menunjukkan bahwa telah berhasil dikembangkan pocket book berbantuan GeoGebra dengan pendekatan PMRI ditunjukkan dengan penilaian validator oleh ahli media diperoleh persentase 89,26%, ahli materi 85,77%, dan tanggapan siswa 90,5%. Berdasarkan analisis data tersebut dinyatakan media pembelajaran berkategori valid. Selanjutnya perhitungan analisis akhir, diperoleh hasil rata-rata nilai kelas eksperimen = 80,5294 dan rata-rata nilai kelas kontrol = 72. Untuk uji hipotesis menggunakan uji t pihak kanan dan diperoleh t = 3,2872, maka rata-rata kelas eksperimen lebih baik daripada rata-rata kelas kontrol. Uji ketuntasan belajar individu dilakukan uji z satu pihak kanan dan diperoleh z = 1,7806, maka ketuntasan belajar individu kelas eksperimen tercapai. Uji ketuntasan belajar klaksikal menggunakan uji proporsi (uji t satu pihak kanan) dan diperoleh t = 6,1842, maka kelas eksperimen telah mencapai ketuntasan belajar secara klasikal. Dengan terpenuhinya uji ketuntasan dan uji beda rata-rata dapat disimpulkan bahwa pocket book berbantuan GeoGebra dengan pendekatan PMRI pada materi segiempat efektif dalam proses pembelajaran matematika.
PENGEMBANGAN MODUL PEMBELAJARAN BERBANTU FLIPBOOK MAKER DENGAN MODEL PEMBELAJARAN NUMBERED HEADS TOGETHER (NHT) BERBASIS TEORI VYGOTSKY MATERI POKOK RELASI DAN FUNGSI
Authors: Pornamasari Evi Intan
Published: October 2017

Penelitian ini bertujuan mengembangkan modul pembelajaran berbantuan software flip book makersehingga menghasilkan media pembelajaran yang layak, serta diharapkan prestasi belajar peserta didikakan lebih meningkat. Penggunaan media dengan model pembelajaran numbered heads together berbasisteori vygotsky terbukti lebih baik dari pada pembelajaran yang menggunakan modul sebelumnya. Penelitianini menggunakan desain pengembangan model ADDIE, yaitu: analysis, design, development,implementation, evalutation. Subjek penelitian adalah peserta didik kelas VIII C dan VIII D SMP N 1Kangkung. Hasil dari validasi ahli baik sekali yaitu ahli media 83,37% dan ahli materi 91,78%. Angkettanggapan peserta didik memperoleh nilai 73,47% artinya baik. Sehingga media tersebut dapat dikatakanvalid. Dari hipotesis uji t pihak kanan diperoleh thitung > ttabel yaitu 3,0703> 1,67 dengan taraf signifikan5%, maka H0 ditolak. Sehingga dapat disimpulkan prestasi belajar siswa dengan menggunakan modulpembelajaran berbantuan flipbook maker dengan model NHT berbasis teori vygotsky lebih baik dari padaprestasi belajar siswa yang menggunakan modul sebelumnya pada materi relasi dan fungsi.
ANALISIS BUTIR SOAL MATEMATIKA PADA INSTRUMEN UJI COBA MATERI SEGITIGA
Authors: Supandi Supandi , Farikhah Lailatul
Published: October 2017

Penelitian ini bertujuan pada upaya untuk mengetahui kualitas butir soal matematika pada materi segitiga. Metode yang digunakan dalam penelitian ini adalah deskriptif kuantitatif. Pengumpulan data dilakukan dengan metode pengumpulan data lapangan . Pembuatan aplikasi berdasarkan analisis hasil dari metode statistik yaitu analisis respon butir.?é?á Hasil dari penelitian ini adalah informasi berupa validitas soal, reliabilitas soal, evaluasi daya pembeda, dan tingkat kesukaran soal. Hasil analisis menunjukkan bahwa kualitas butir soal dari tingkat validitas soal, yang valid sebesar 70% dan tidak valid sebesar 30%. Dari tingkat reliabilitas soal dengan taraf signifikansi 5% soal dinyatakan reliabel. Berdasarkan tingkat kesukaran soal?é?á 60% berada pada kategori mudah, 30% berada pada kategori sedang, dan 10% berada pada kategori sukar. Daya beda soal menunjukkan 50% soal dikategorikan baik dan50% dengan kategori cukup. Berdasarkan hasil analisis data, dapat disimpulkan?é?á bahwa kualitas soal memiliki validitas dan reliabilitas yang tinggi, sedangkan dari tingkat kesukaran tergolong mudah dan daya bedanya tergolong cukup.
EFEKTIFITAS MODEL PEMBELAJARAN TEAMS GAMES TOURNAMENT DENGAN PENDEKATAN SAINTIFIK TERHADAP KEMAMPUAN PEMECAHAN MASALAH MATEMATIKA SISWA KELAS VIII SMPN 4 TAMAN
Authors: Yustitia Via
Published: October 2017

Tujuan penelitian ini adalah untuk mengetahui: (1) kemampuan pemecahan masalah pada materi aljabar siswa yang mendapat pembelajaran TGT dengan pendekatan saintifik; (2) kemampuan pemecahan masalah siswa yang mendapat pembelajaran TGT dengan pendekatan saintifik dengan yang mendapat pembelajaran klasikal dengan pendekatan saintifik.Populasi penelitian ini adalah siswa kelas VIII SMP Negeri 4 Taman. Pengambilan sampel dengan teknik simple random sampling diperoleh dua kelas, yaitu kelas VIII A sebagai kelas eksperimen dan kelas VIII B sebagai kelas kontrol. Pengumpulan data dilakukan dengan metode dokumentasi, tes, observasi, dan angket. Analisis data menggunakan uji t dan uji proporsi. Hasil penelitian menunjukkan bahwa bahwa rata-rata kemampuan pemecahan masalah siswa yang mendapat pembelajaran TGT dengan pendekatan saintifik lebih baik daripada yang mendapat pembelajaran klasikal dengan pendekatan saintifik. Berdasarkan uraian tersebut dapat disimpulkan bahwa model pembelajaranTGT dengan pendekatan saintifik lebihefektif dalam meningkatkan kemampuan pemecahan masalah siswa kelas VIII SMP Negeri 4 Taman pada materi aljabar.
PROFIL REPRESENTASI MATEMATIS SISWA KELAS XII SEKOLAH MENENGAH ATAS DALAM PEMECAHAN MASALAH BERDASARKAN PERSPEKTIF KEMAMPUAN MATEMATIKA
Authors: Zuhri Muhammad Saifuddin , Rubowo Maya Rini
Published: October 2017

Tujuan khusus dari penelitian ini adalah untuk mendeskripsikan profil representasi matematis siswa kelas XII Sekolah Menengah Atas dalam pemecahan masalah berdasarkan perspektif kemampuan matematika. Jenis penelitian ini adalah kualitatif deskriptif. Subjek dalam penelitian ini adalah siswa kelas XII Sekolah Menengah Atas dalam pemecahan masalah berdasarkan perspektif kemampuan matematika.. Pemilihan subjek pada penelitian ini menggunakan teknik purposive sampling dengan pertimbangan: siswa kelas XII Sekolah Menengah Atas sudah cukup memperoleh banyak materi pokok matematika, kemampuan siswa dalam mengemukakan pendapat baik secara lisan dan tertulis, dan siswa dengan kemampuan matematika tinggi. Pengumpulan data dilakukan dengan teknik tes tertulis dan wawancara. Analisis data dilakukan berdasarkan data hasil tes tertulis dan data hasil wawancara. Kemudian dilakukan triangulasi metode untuk menghasilkan data dari subjek penelitian yang valid. Hasil yang diperoleh adalah siswa dengan kemampuan matematika tinggi kelas XII Sekolah Menengah Atas dalam pemecahan masalah adalah: membuat persamaan matematik dari representasi yang diberikan, penyelesaian masalah dengan melibatkan ekspresi matematik, menyajikan kembali data atau informasi dari suatu representasi ke representasi grafik, diagram atau tabel, menggunakan representasi visual untuk menyelesaikan masalah Membuat situasi masalah berdasarkan representasi yang diberikan, menjawab permasalahan dengan menggunakan kata-kata atau teks tertulis.
PENGEMBANGAN STRATEGI PERMAINAN TRADISIONAL SUNDA MANDA PADA PEMBELAJARAN MATEMATIKA DI SMP
Authors: Rahmawati Noviana Dini , Buchori Achmad , Bhihikmah Bhihikmah
Published: October 2017

Penelitian R & D dengan model Plomp ini bertujuan untuk mengembangkan stargei pembelajaran sunda manda bagi siswa SMP. Hasil penelitian menunjukkan bahwa rata-rata persentase validasi strategi permainan sunda manda sebesar 92,15% yang berarti kategori strategi permainan sunda manda sangat layak. Sedangkan kepraktisan ditunjukkan dengan persentase yang diperoleh 97,3% yang artinya sangat baik dan sangat layaksehingga dapat disimpulkan bahwa strategi permainan sunda manda praktis dapat digunakan.melalui nilai rata-rata pretes yaitu 51,5625 dan postes yaitu 79,1935, serta respon siswa yang diperoleh skor 78,45% sehingga dapat disimpulkan bahwa strategi permainan sunda manda efektif untuk digunakan.
ANALISIS KESALAHAN SISWA DALAM MENYELESAIKAN SOAL PENJUMLAHAN DAN PENGURANGAN PECAHAN DI KELAS VII SMPN MODEL TERPADU MADANI
Authors: Ramlah Ramlah , Bennu Sudarman , Paloloang Baharuddin
Published: October 2017

Tujuan penelitian ini adalah untuk mendeskripsikan jenis-jenis kesalahan yang dilakukan oleh siswa di kelas VII SMPN Model Terpadu Madani dalam menyelesaikan soal penjumlahan dan pengurangan pecahan. Jenis penelitian ini adalah penelitian kualitatif. Subjek penelitian ini adalah 3 siswa yang diambil dari 25 siswa kelas VII Lamalonda. Hasil penelitian menunjukkan bahwa kesalahan-kesalahan siswa yaitu kesalahan konseptual dan kesalahan prosedural. Kesalahan konseptual yang dilakukan oleh siswa meliputi (1) kesalahan  konsep yaitu kesalahan  mengubah bentuk bilangan bulat menjadi pecahan dan kesalahan menjabarkan pecahan negatif; (2) kesalahan fakta yaitu kesalahan tidak menuliskan tanda negatif pada hasil pengurangan yang seharusnya bernilai nagatif dan kesalahan penulisan operasi hitung dan (3) kesalahan prinsip yaitu kesalahan menentukan pecahan senilai dan kesalahan menjumlah atau mengurangkan bilangan bulat dengan pecahan. Sedangkan kesalahan prosedural yang dilakukan oleh siswa meliputi (1) kesalahan operasi hitung; (2) kesalahan menyederhanakan pecahan; (3) kesalahan prosedur tidak lengkap dan (4) kesalahan mengerjakan sembarang.
KONSEP REVISI TAKSONOMI BLOOM DAN IMPLEMENTASINYA PADA PELAJARAN MATEMATIKA SMP
Authors: Effendi Ramlan
Published: October 2017

Tujuan kajian ini adalah agar dapat menyusun soal-soal matematika sesuai konsep revisi taksonomi bloom. Taksonomi Bloom merupakan suatu tingkatan dalam mengidentifikasikan keterampilan siswa dari jenjang yang dasar sampai  yang tertinggi. Tingkatan dalam revisi taksonomi bloom yang dilakukan oleh Kratwohl dan Anderson meliputi mengingat (C1), memahami (C2), mengaplikasikan (C3), menganalisis (4), mengevaluasi (5) dan mencipta (6). Tingkatan 44,5, dan 6 sering diklasifikasikan sebagai tingkat keterampilan berpikir tingkat tinggi (high order thinking skills). Guru perlu mengembangkan soal-soal sesusai revisi taksonomi bloom khususnya  level C4, C5 dan C6 agar siswa terbiasa menyelesaikan soal yang mengembangkan keterampilan berpikir tingkat tinggi tersebut.
EFEKTIVITAS PEMBELAJARAN KOOPERATIF TIPE GROUP INVESTIGATION TERHADAP KEMAMPUAN BERPIKIR KRITIS MAHASISWA PADA MATA KULIAH ANALISIS RIIL
Authors: Utami Rizky Esti
Published: October 2017

Penelitian ini merupakan penelitian eksperimen yang bertujuan untuk mengetahui  efektivitas model pembelajaran kooperatif tipe group investigation terhadap peningkatan kemampuan berpikir kritis mahasiswa pada mata kuliah analisis riil. Populasi dalam penelitian ini adalah seluruh mahasiswa program studi pendidikan matematika semester 6 IKIP PGRI Semarang. Pengambilan sampel dilakukan dengan Cluster Random Sampling yaitu pengambilan unit mahasiswa sebanyak dua kelas dari beberapa kelas yang ada. Dalam hal ini pengambilan 2 kelas dari  9 kelas yang ada. Dari 2 kelas tersebut diundi secara acak untuk mendapatkan kelas eksperimen dan kelas kontrol. Teknik pengumpulan datanya dilakukan melalui metode dokumentasi, observasi, dan tes.  Teknik analisis datanya menggunakan analisis statistik data kuantitatif. Hasil penelitian menunjukkan bahwa kemampuan berpikir kritis mahasiswa yang menerapkan model pembelajaran kooperatif tipe group investigation  lebih baik dari kemampuan berpikir kritis mahasiswa yang menerapkan pembelajaran konvensional.
PENGARUH LATIHAN SENAM YOGA TERHADAP KADAR GLUKOSA DARAH DAN KOLESTEROL PADA PENDERITA DIABETES MELLITUS TIPE 2
Authors: Irmawati Intan
Published: October 2017

Penelitian ini bertujuan untuk mengetahui: (1) pengaruh latihan senam yoga terhadap kadarglukosa darah dan kolesterol darah, (2) perbedaan pengaruh latihan senam yoga terhadap kadarglukosa darah dan kolesterol darah antara penderita diabetes mellitus tipe 2 dengan kadar glukosadarah awal di bawah dan di atas 250 mg/dl. Metode penelitian adalah eksperimen. Populasipenelitian adalah anggota klub senam Prolanis di Kecamatan talang kelapa, banyu asin. Sampelpenelitian 25 penderita diabetes mellitus tipe 2 yang diambil dengan teknik Purposive Sampling.Seluruh data penelitian diperoleh melalui tes kadar glukosa darah dan kolesterol denganGlukometer. Teknik analisis data yang digunakan adalah paired t-tes dan independen t-tes padataraf signifikan α = 0,05. Hasil penelitian menunjukkan bahwa: (1) senam yoga dapat menurunkankimiawi darah secara signifikan, terbukti dari nilai p = 0.000 < 0.05, (2a) ada perbedaan pengaruhpenurunan kadar glukosa darah yang signifikan antara penderita diabetes mellitus tipe 2 dengankadar glukosa darah <250 mg/dl dan > 250 mg/dl, terbukti dari nilai p = 0.000 < 0.05, (2b) tidak adaperbedaan pengaruh penurunan kolesterol yang signifikan antara penderita diabetes mellitus tipe 2dengan kadar glukosa darah < 250 mg/dl dan >250 mg/dl, terbukti dari nilai p = 0.605 > 0.05. Latihansenam yoga memberikan pengaruh yang baik terhadap penurunan kimiawi darah.
Pengembangan Pembelajaran Berbasis Saintifik pada Materi Dinamika Rotasi dan Kesetimbangan Benda Tegar untuk Meningkatkan Kemampuan Berpikir Kritis dan Komunikasi Verbal Siswa SMA
Authors: Setyawan Dhimas Nur , Sarwanto Sarwanto , Aminah Nonoh Siti
Published: October 2017

Hasil daya serap UN 2015 pada materi dinamika rotasi dan kesetimbangan benda tegar di Kota Magelang 65,08 masih rendah dibandingkan dengan daya serap tingkat Provinsi Jawa Tengah 67,13 maupun tingkat nasional 65,24, sehingga perlu dilakukan pembelajaran berbasis saitifik. Penelitian ini yang bertujuan untuk: (1) mendeskripsikan karakteristik pembelajaran berbasis saintifik; (2) mendeskripsikan kelayakan pembelajaran berbasis saintifik; (3) menganalisis efektivitas penggunaan pembelajaran berbasis saintifik dalam meningkatkan kemampuan berpikir kritis dan komunikasi verbal siswa. Pengembangan modul fisika berbasis saintifik dilakukan dengan penelitian Research and Development (R&D) menggunakan model Borg and Gall yang disederhanakan Tim Puslitjaknov [1] terdiri dari 5 tahap utama yaitu analisis pembelajaran, mengembangkan draft awal, validasi pembelajaran dan revisi, uji coba skala kecil dan revisi, uji coba skala besar dan revisi, dan diseminasi. Produk pembelajaran dikemas dalam bentuk modul. Modul fisika berbasis saintifik dinilai oleh: ahli materi, ahli media, dan ahli bahasa; dua praktisi guru fisika SMA; dan dua teman sejawat serta respon siswa. Analisis data yang digunakan adalah analisis deskriptif, kualitatif, dan N-Gain. Hasil penelitian dan pengembangan disimpulkan bahwa: 1) pembelajaran berbasis saintifik yang dikembangkan pada materi dinamika rotasi dan kesetimbangan benda tegar, menggunakan langkah menyajikan paparan masalah, menanya, berhipotesis, mengukur, menganalisis, menyimpulkan, mengomunikasikan. Selain itu, terdapat tugas bercerita mencari fenomena sesuai materi, soal latihan, dan soal evaluasi; 2) pembelajaran berbasis saintifik yang dikembangkan telah layak digunakan dengan kategori kelayakan sangat baik/sangat layak ditinjau dari kelayakan materi, media, dan bahasa; 3) pembelajaran berbasis saintifik pada materi dinamika rotasi dan kesetimbangan benda tegar efektif dalam meningkatkan kemampuan berpikir kritis dan komunikasi verbal siswa salah satu SMA di Kota Magelang. Peningkatan kemampuan berpikir kritis dengan N-gain score rata-rata 0,50 berkategori sedang pada kelas eksperimen dan 0,46 berkategori sedang pada kelas kontrol. Kemampuan komunikasi verbal pada kelas eksperimen mengalami peningkatan pada setiap pertemuan dengan N-Gain score rata-rata 0,37 pada kategori sedang.
Pengaruh Metode SDEP (Simulasi, Demonstrasi, Eksperimen, Presentasi) dan Kemampuan Awal Siswa Terhadap Hasil Belajar Fisika
Authors: Raharjo Semiono
Published: October 2017

Penelitian ini bertujuan untuk mengetahui pengaruh metode SDEP dan kemampuan awal siswa terhadap hasil belajar Fisika aspek kognitif pada topik Pengukuran, mengetahui perbedaan peningkatan hasil belajar Fisika aspek kognitif pada topik Pengukuran antara kelas yang diberikan metode SDEP dengan metode ceramah. Populasi penelitian meliputi kelas X SMAN 1 Piyungan dengan jumlah 160 siswa. Sampel penelitian meliputi kelas XA sebagai kelas eksperimen dan kelas XC sebagai kelas kontrol masing-masing berjumlah 23 siswa. Teknik pengumpulan data menggunakan tes dengan instrumen soal pretest dan posttest. Teknik analisis data menggunakan uji anacova dan N-Gain. Hasil analisis dengan uji anacova diperoleh nilai p = 0,004 untuk metode SDEP dan p = 0,000 untuk kemampuan awal dan semua variabel secara simultan. Analisis N-Gain diperoleh g = 0,7 (kriteria tinggi) untuk kelas eksperimen dan g = 0,5 (kriteria sedang) untuk kelas kontrol. Karena nilai p < 0,005 maka dapat disimpulkan bahwa terdapat pengaruh metode SDEP dan kemampuan awal siswa terhadap hasil belajar Fisika aspek kognitif pada topik Pengukuran, metode SDEP dapat meningkatkan hasil belajar Fisika aspek kognitif pada topik Pengukuran, terdapat perbedaan peningkatan hasil belajar Fisika aspek kognitif pada topik Pengukuran antara kelas yang diberikan metode SDEP dengan metode ceramah.
Untersuchungskonzept zur praxisnahen Abschätzung des Korrosionsverhaltens von Schließringbolzenverbindungen
Authors: Nowak Karina , Fuchs Normen , Lebelt Peter
Published: October 2017

Kurzfassung

Im Rahmen eines Forschungsprojektes der Fraunhofer-Einrichtung für Großstrukturen in der Produktionstechnik (Fraunhofer IGP) und des Institutes für Korrosionsschutz Dresden GmbH (IKS Dresden) erfolgten Untersuchungen zur Entwicklung eines Untersuchungskonzeptes mit dem Ziel einer praxisnahen Abschätzung des Korrosionsverhaltens von Schließringbolzenverbindungen (SRB-Verbindungen). Die Untersuchungen basieren auf einer statistischen Versuchsplanung in Kombination mit Korrosionsprüfverfahren im Labor und in der Freibewitterung. Im ersten Schritt wird die Schließringbolzenverbindung genauer betrachtet und Einflussfaktoren auf das Korrosionsverhalten der Verbindungen aufgezeigt. Auf Basis dieser Faktoren wird ein Versuchsplan vorgestellt, der zum einen die Anzahl und Konfiguration der Probekörper vorgibt und zum anderen zur Auswertung der Einflussfaktoren auf das Korrosionsverhalten der Probekörper dient. Aufbauend auf dem Versuchsplan wird ein Prüfablauf für die Laboruntersuchung und die Freibewitterung an drei Standorten unterschiedlicher medialer Belastung für Schließringbolzenverbindungen erläutert. Die Darstellung von Versuchsergebnissen und die kritische Auseinandersetzung erfolgt exemplarisch für die Laboruntersuchung.
Taguchi optimization of surface roughness and flank wear during the turning of DIN 1.2344 tool steel
Authors: Kara Fuat
Published: October 2017

In this study, a turning operation was applied to DIN 1.2344 hot work tool steel under dry machining conditions. The optimum machining conditions were determined by investigating the surface roughness (Ra) and the flank wear (Vb) depending on the machining parameters. Experiments were performed according to the Taguchi L9 orthogonal array and signal/noise (S/N) ratios were used in the evaluation of the test results. Optimum Ra and Vb values were determined by Taguchi optimization. The effects of the machining parameters on Ra and Vb were found with the help of analysis of variance (ANOVA). According to the ANOVA results, the most important parameter affecting Ra and Vb was feed rate. Two different multiple regression analyses (linear and quadratic) were conducted for the experimental results. A higher correlation coefficient (R2) was obtained with the quadratic regression model, which showed a value of 0.99 for both Ra and Vb. Finally, confirmation tests were performed and showed that the optimization has been successfully implemented. By the Taguchi analysis the optimum results for both surface roughness and flank wear were found to be a cutting speed of 120 m × min−1, a feed rate of 0.15 mm × rev−1 and a depth of cut of 0.5 mm. The results of the calculations and the confirmation tests for Ra were 0.84 μm and 0.80 μm, and for Vb, 0.0892 mm and 0.0824 mm, respectively.
Microstructure, wear and friction behavior of AISI 1045 steel surfaces coated with mechanically alloyed Fe16Mo2C0.25Mn/Al2O3-3TiO2 powders
Authors: Özel Cihan , Akgün Gökçen , Gürgenc Turan
Published: October 2017

The surface of AISI 1045 steel was coated using the flame spray technique. Iron-based superalloy (Fe16Mo2C0.25Mn) powders were used as matrix material and a mixture of mechanically alloyed 10 wt.-% Fe16Mo2C0.25Mn and 90 wt.-% Al2O3–3TiO2 powders was used as reinforcing material. The mechanical alloying process was performed by milling with an attritor for 60 hours. The coating material comprised of a mixture of the matrix (Fe16Mo2C0.25Mn) powder and mechanically alloyed reinforcing powders at varying rates of 5, 10 and 15 %, respectively. The microstructure, microhardness, adhesive wear behaviors and the coefficients of friction of the coated specimens were examined. It was observed that defects increased and cracks formed on the interface, depending on the increase in the reinforcing ratio. It was determined that the coefficient of friction and wear loss increased by the increasing load in all specimens. The minimum wear loss was observed for the specimen with 10 % reinforcement and the maximum wear loss was observed for the specimen with 15 % reinforcement. The highest average coefficient of friction by the applied load was obtained for the coating with 10 % reinforcement and the lowest average coefficient of friction was obtained for the specimen with 5 % reinforcement.
Association of Increased Tpeak-to-end/QT ratio with Malignant Ventricular Arrhythmias in Acute Anterior ST-Segment Elevation Myocardial Infarction
Authors: Reza Abeeda Tasnim , Rashid Md Mamunur , Hossain Md Mohsin , Hussain Khondoker Shaheed , Rahman Md Tanvir , Ahsan Mohammad Morshedul , Matin Mohammad Abdul , Afroz Delara , Cader Aaysha , Md Jafor Abul Hasnat
Published: October 2017

Background: Increased Tpeak-to-end/QT ratio on 12 lead surface electrocardiogram (ECG) has been shown to be the predictor of arrhythmogenesis in various cardiac disorders. There is limited data regarding association of these two parameters with malignant ventricular arrhythmias (MVA) in acute ST-segment elevation myocardial infarction (STEMI) patients. Objectives: This study was conducted to evaluate association of increased Tpeak-to-end/QT ratio with MVAs in acute anterior STEMI. Methods: 178 patients with acute anterior STEMI admitted within 12 hours of onset of chest pain into the Coronary Care Unit, Department of Cardiology, National Institute of Cardiovascular Diseases, Dhaka, were enrolled from November 2015 to October 2016. Tpeak-to-end/QT ratio was calculated from surface ECG at the time of admission. The patients were divided into two groups, group I and II according to normal (?0.25) and increased Tpeak-to-end/QT ratio (>0.25). Each group was monitored for development of MVAs for the first 48 hours of myocardial infarction. Results: MVAs were significantly higher in group II than group I (19.5% vs 3.1%, p<0.001). Multivariate regression analysis showed significant association (p=0.002) of increased Tpeak-to-end/QT ratio with MVAs (Odds Ratio, 3.845).Receiver operating characteristic (ROC) curve analysis showed that Tpeak-to-end/QT ratio <0.25 had a negative predictive value of 96.88% for the prediction of MVAs. Conclusion: The study demonstrated that there was significant association of increased Tpeak-to-end/QT ratio with malignant ventricular arrhythmias in acute anterior STEMI patients. Thus analysis of 12 lead surface ECG on admission may help predict malignant ventricular arrhythmias in the first 48 hours of acute anterior myocardial infarction and close monitoring with prompt management may be ensured in high risk patients.Bangladesh Heart Journal 2017; 32(1) : 10-17
Association of Visceral Adiposity Index Score with the Severity of Coronary Artery Disease in Patients with Ischemic Heart Disease
Authors: Singha Chayan Kumar , Biswas Eshita , Choudhury Amal Kumar , Khalequzzaman Md , Khanam Rawshan Arra , Mahmood Sanzida , Paul Nandita
Published: October 2017

Background: Ischemic Heart Disease (IHD) is the leading cause of death throughout the world and obesity especially visceral adiposity (central obesity has significant influence for its development & progression. Visceral adiposity index (VAI) is a novel sex specific index which had significant correlation with visceral adiposity.Objectives: To evaluate the impact of cut-off points of VAI defining visceral adipose dysfunction (VAD) on the angiographic severity of coronary artery disease in patients of IHD.Methods: A total of 100 patients with IHD were divided into Case (of which 50 patients of IHD with VAD positive) and Control group (of which 50 patients of IHD with VAD negative). Then clinical, biochemical, echocardiographic and coronary artery angiographic indexes (determined by Gensini score) were acquired in relation to VAI.Results: VAD positive group had more significant form of coronary artery disease in term of Gensini score than VAD negative group.The mean level of Visceral Adiposity Index (VAI) was observed 3.1±0.9 and 2.1±0.6 in significant CAD (Gensini score ?36) and insignificant CAD (Gensini score<36) respectively. The difference of mean VAI between the significant and insignificant CAD groups were statistically significant (p=<0.001). First group (VAD positive) also had more CAD risk factors like hypertension, diabetes mellitus and dyslipidemia which were significantly higher than second group (VAD negative) (p=0.02, 0.002, 0.01). Univariate and multivariate analysis revealed that out of the 8 variables hypertension, dyslipidemia, diabetes mellitus, waist circumference and visceral adiposity index were found to be the independently significant predictors of severe CAD patients with ORs being 1.61 vs. 1.52, 1.97 vs. 1.36, 2.19 vs. 1.97, 1.94 vs. 1.61 and 3.89 vs. 3.49 respectively. Thus the VAI was found to be more strong predictor of the severity of CAD.Conclusion: VAI is a simple indicator of visceral adipose mass & was markedly associated with the severity of coronary artery disease in IHD patients.Bangladesh Heart Journal 2017; 32(1) : 36-39
Age Distribution of Aortic Sclerosis among Bangladeshi Population
Authors: Saleh Mohammed Abaye Deen , Hasan Pratyay , Nahar Khyrun , Chowdhury Abdul Wadud , Ahmed Mohsin , Kabir Syed Rezwan , Amin Md Gaffar , Islam Kazi Nazrul
Published: October 2017

Aortic sclerosis (ASc) is defined as thickening or calcification of the aortic valve without significant obstruction of blood flow. Aortic sclerosis is diagnosed when in echocardiography, thickening and calcification of one or more cusps of a tricuspid aortic valve is manifested, whereas in aortic stenosis, cusp separation is restricted and the velocity through the aortic valve is > 2.5 m/s. Its prevalence increases with age. Aortic valve stenosis is associated with systemic endothelial dysfunction, and it carries a 50% increase in risk of cardiac death or myocardial infarction. As aortic sclerosis has proved to be more and more relevant in recent days, it has been important to identify epidemiological data and demographic information of aortic sclerosis in Bangladeshi population. This study tried to determine age distribution of aortic sclerosis in Bangladehsi population. Median age of aortic sclerosis patients was 65 years (mean 67 ± 12 years), most of the patients (17.2%) were in 56-60 years of age group. The same statement holds correct for females, where highest number of patients (7.7% of total patients) were in the same age group. For the males, the highest number of patients (11% of total patients) were in 61-65 years of age group. The minimum age was 45 years for both males and females. Although the minimum age is same for both sex, females are affected a bit earlier than males, and statistically significant difference was found between mean ages of two sexes. Most of the aortic sclerotic patients are below the usually used age cut off of 65 years. There is significant difference between mean age of presentation of aortic sclerosis between males and females. Further study should be undertaken to understand these effects more clearly.Bangladesh Heart Journal 2017; 32(1) : 50-54
Sub-ungual Glomus Tumor: Study of 20 Cases
Authors: Uddin Md Maiyeen , Biswas Swapan Kumar , Rahman Md Habibur , Karmakar Narayan Chandra , Rahman Md Masudur , Alam Syed Asif Ul , Mondal Anadi Ranjan
Published: October 2017

Glomus tumors are benign hamartoma of glomus body. It accounts 1-5% of all soft tissue tumors of hand. They can cause recurrent episodes of intense lancinating pain and disability. Patients often undergo undiagnosed or misdiagnosed for many years because the tumors are small. Twenty patients were operated during the period of 2010 to 2015. Most of the cases were selected on the basis of clinical diagnosis. The help of magnetic resonance imaging was taken in suspicious cases. The only treatment of glomus tumor is total surgical excision. In this study surgical excision were performed by direct trans-ungual approach. All patients showed dramatic relief of pain after surgical excision. Early diagnosis and surgical excision decreases patient's sufferings from severe pain and disability. Eagerness in early diagnosis and surgical excision can reduce long period of sufferings.Faridpur Med. Coll. J. Jul 2017;12(2): 64-67
Update Management of Chikungunya
Authors: Mohammad Arif Khan
Published: October 2017

Chikungunya is a viral infection first detected after an outbreak in Tanzania in 1952. Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that belongs to the Togaviridae family. Incidence increases in rainy season. Exact pathogenesis is not clearly understood. Fever and arthralgia/arthritis is the striking feature of Chikungunya fever1. Few patient may develop neurological and other complication. Joint pain may persist for several years. Investigations for confirmation are Real-time PCR, Virus specific IgM antibodies and IgG antibodies. Treatments are supportive. Most patients recover completely. Death is very rare. Reducing natural & artificial water filled container habitats is the principal step of prevention.Faridpur Med. Coll. J. Jul 2017;12(2): 82-85
A Case of Invasive Mole
Authors: Ahmed Shahana , Shaha Dipti Rani
Published: October 2017

Invasive mole is a condition where a molar pregnancy, such as a partial hydatidiform mole or complete hydatidiform mole, invades the wall of the uterus, potentially spreading and metastasizing to other parts of the body. Here is a case who presented with history of evacuation for molar pregnancy. She presented with irregular P/V bleeding on and off and after admission silent perforation with massive haemoperitoneum was detected for which emergency laparotomy was done. She recovered and was followed up till her b-hCG levels were within normal limits. As patient presented to us with haemoperitoneum and on laparotomy, there was invasion into whole of the uterus, it could not be saved and hysterectomy was done.Faridpur Med. Coll. J. Jul 2017;12(2): 86-87
An Analytical Study of Determinants of Non-Performing Loans: Evidence from Non-Bank Financial Institutions (NBFIs) of Bangladesh
Authors: Rifat Apel Mahmood
Published: October 2017

The main focus of this study is to analyze the determinants of non-performing loan (NPL) in Non-Bank Financial Institution (NBFI) sector in Bangladesh. Both macroeconomic and firm-specific variables are tested to determine the impact on classified loan ratio. A panel data-set consisting of seven NBFI with a time-span of 12 years (2003-2014) is analyzed for this purpose. Among macroeconomic variables, GDP growth rate, inflation rate and broad money in GDP are used. To capture management ability, firm-specific variables like, loan growth, loan to asset ratio, return on asset and relative size of firm were included in the study. Results show that firm-specific factors were more significant for non-performing loan of the NBFIs. Among macroeconomic variables, money supply was found to have significant impactJournal of Business and Technology (Dhaka) Vol.11(1-2) 2016; 55-67
Debit Card Adoption Attributes and Customer Satisfaction: A Study on Dutch-Bangla Band Ltd.
Authors: Mynuddin Md
Published: October 2017

Dutch-Bangla Bank Ltd (DBBL) is one of the most innovative and technologically advanced banks. It stands as a leader in the country's banking sector. Recently it was found that a large number of customers were using debit card for various purposes like convenient, speedy money transaction, easy maintenance etc. To assess which factors were related to debit card adoption, a questionnaire was developed. The survey was conducted among 239 customers from three different branches of Sylhet city. The study showed the significantly influencing debit card adoption factors, which were transaction transparency, shopping through Point-of-Sell (POS) utility bill payment, easiest way to maintain relationship with bank community and so on.Journal of Business and Technology (Dhaka) Vol.11(1-2) 2016; 129-140
Learning to live and work together in an ecovillage community of practice
Authors: Mychajluk Lisa
Published: October 2017

Ecovillages are citizen-organised residential communities that strive for a more sustainable way of life based on a culture of cooperation and sharing, as deemed necessary to support a shift to a post carbon world (Dawson, 2006; Lockyer & Veteto, 2013; Korten, 2006). While much can potentially be learned from the study of these experimental sustainable communities, perhaps their greatest contribution is to help us understand how to transition from individualism and competition in order to live ‘smaller, slower and closer (Litfin, 2014)’. Drawing on a social theory of practice (Wenger, 1998) and concept of communities of practice (Lave & Wenger, 1991; Wenger, 1998), this paper considers how one ecovillage is learning the social competencies necessary to live and work well "in community", and in doing so, it coconstructs and sustains a cooperative culture.
The social economy as produced space: the ‘here and now’ of education in constructing alternatives
Authors: Brown Scott
Published: October 2017

This article approaches adult learning within the social economy through a critical and spatial lens. First, I approach the critical pedagogy of Freire, outlining the dialectical relationship between subjectivity and objectivity enacted in the development of critical consciousness. Carrying this dialogical argumentative forward, I go on to show how the critical geography of Lefebvre ‘unpacks’ this dialectic onto space and place, grounding pedagogical apprehension in a critical geography which is more directly set up to confront and engage with capitalism as a spatial force. Drawing from some of the social enterprise literature, I then utilise Lefebvre’s ‘spatial triad’ to demonstrate how the perceived, conceived and lived facets of space can shed light on integrative areas of adult learning that together constitute a platform for a potential ‘trial by space’ for alternatives.
Evaluation of Adhesion and Hysteresis Friction of Rubber–Pavement System
Authors: Al-Assi Mohammad , Kassem Emad
Published: October 2017

Tire-pavement friction is a key component in road safety. Adhesion and hysteresis are the two main mechanisms that affect the friction between rubber tires and pavements. This study experimentally examined the relationship between rubber–pavement adhesion and friction. The adhesive bond energy between rubber and pavement surfaces was calculated by measuring the surface energy components of rubber and aggregates. The friction was measured in the laboratory using a dynamic friction tester. The results revealed that there is a fair correlation between the adhesive bond energy and measured coefficient of friction. A rubber–pavement system with higher adhesion provided higher friction at low speed. In addition, the results demonstrated that there is a strong correlation between rubber–pavement friction and rubber properties. Softer rubber provided higher friction and vice versa. The results of this study provide an experimental verification of the relationship between adhesion and pavement surface friction. The adhesive bond energy and rubber rheological properties could be incorporated in computational models to study tire-pavement friction in different conditions (e.g., speed and temperature).
Profitability Analysis of Soybean Oil Processes
Authors: Cheng Ming-Hsun , Rosentrater Kurt
Published: October 2017

Soybean oil production is the basic process for soybean applications. Cash flow analysis is used to estimate the profitability of a manufacturing venture. Besides capital investments, operating costs, and revenues, the interest rate is the factor to estimate the net present value (NPV), break-even points, and payback time; which are benchmarks for profitability evaluation. The positive NPV and reasonable payback time represent a profitable process, and provide an acceptable projection for real operating. Additionally, the capacity of the process is another critical factor. The extruding-expelling process and hexane extraction are the two typical approaches used in industry. When the capacities of annual oil production are larger than 12 and 173 million kg respectively, these two processes are profitable. The solvent free approach, known as enzyme assisted aqueous extraction process (EAEP), is profitable when the capacity is larger than 17 million kg of annual oil production.
Multivariate Dependence beyond Shannon Information
Authors: James Ryan , Crutchfield James
Published: October 2017

Accurately determining dependency structure is critical to understanding a complex system’s organization. We recently showed that the transfer entropy fails in a key aspect of this—measuring information flow—due to its conflation of dyadic and polyadic relationships. We extend this observation to demonstrate that Shannon information measures (entropy and mutual information, in their conditional and multivariate forms) can fail to accurately ascertain multivariate dependencies due to their conflation of qualitatively different relations among variables. This has broad implications, particularly when employing information to express the organization and mechanisms embedded in complex systems, including the burgeoning efforts to combine complex network theory with information theory. Here, we do not suggest that any aspect of information theory is wrong. Rather, the vast majority of its informational measures are simply inadequate for determining the meaningful relationships among variables within joint probability distributions. We close by demonstrating that such distributions exist across an arbitrary set of variables.
Research Foundations for Evidence-Informed Early Childhood Intervention Performance Checklists
Authors: Dunst Carl J.
Published: October 2017

The research evidence for early childhood intervention practices performance checklists is described. Performance checklists include lists of the tasks or steps required to complete a practice competently. The checklists were developed using a conceptualization-operationalization-measurement framework where findings from research syntheses and empirical studies informed the selection or development of checklist indicators. This paper includes a meta-review of empirical evidence demonstrating practice-outcome relationships consistent with the purposes and goals of each of the performance checklists. Findings from more than 200 narrative reviews, meta-analyses, integrative reviews, and other types of research syntheses were the sources of evidence and foundations for 26 early childhood intervention performance checklists. The research evidence, taken together, indicates that the checklist indicators have a substantial evidence base for each of the performance checklist practices. Strengths and limitations of the meta-review are described.
Grey Relational Analysis for Insulation Condition Assessment of Power Transformers Based Upon Conventional Dielectric Response Measurement
Authors: Liu Jiefeng , Zheng Hanbo , Zhang Yiyi , Wei Hua , Liao Ruijin
Published: October 2017

Conventional dielectric response measurement techniques, for instance, recovery voltage measurement (RVM), frequency domain spectroscopy (FDS) and polarization–depolarization current (PDC) are effective nondestructive insulation monitoring techniques for oil-impregnated power transformers. Previous studies have focused mainly on some single type of dielectric measurement method. However, the condition of oil paper insulation in transformer is affected by many factors, so it is difficult to predict the insulation status by means of a single method. In this paper, the insulation condition assessment is performed by grey relational analysis (GRA) technique after carefully investigating different dielectric response measurement data. The insulation condition sensitive parameters of samples with unknown insulation status are extracted from different dielectric response measurement data and then these are used to contrast with the standard insulation state vector models established in controlled laboratory conditions by using GRA technique for predicting insulation condition. The performance of the proposed approach is tested using both the laboratory samples and a power transformer to demonstrate that it can provide reliable and effective insulation diagnosis.
Optimal Cold-Start Control of a Gasoline Engine
Authors: Hedinger Raffael , Elbert Philipp , Onder Christopher
Published: October 2017

This article analyzes the influence of the ignition retardation on the fuel consumption, the cumulative tailpipe hydrocarbon emissions, and the temperature inside the three-way catalytic converter in a gasoline direct injection engine operated under idling conditions. A dedicated cylinder-individual, model-based, multivariable controller was used in experiments in order to isolate the effect of the ignition retardation on the hydrocarbon emissions as much as possible. An optimal control problem for a gasoline engine at a cold-start is formulated, which is used to interpret the experimental data obtained. The corresponding goal is to minimize the fuel consumption during an initial idling phase of a fixed duration while guaranteeing that the three-way catalytic converter reaches a sufficiently high final temperature and at the same time making sure that the cumulative hydrocarbon emissions stay below a given limit. The experimental data indicates that the engine should be operated with maximum ignition retardation in order to reach any temperature inside the three-way catalytic converter as quickly as possible concurrently with minimum tailpipe emissions and with the minimum possible fuel consumption.
Searching for Jet Emission in LMXBs: A Polarimetric View
Authors: Baglio Maria , D’Avanzo Paolo , Campana Sergio , Russell Dave
Published: October 2017

We present results taken from a study aiming at detecting the emission from relativistic particles jets in neutron star-low mass X-ray binaries using optical polarimetric observations. First, we focus on a polarimetric study performed on the persistent LMXB 4U 0614+091. Once corrected for interstellar effects, we measured an intrinsic linear polarization in the r-band of ~3% at a 3σ confidence level. This is in-line with the observation of an infrared excess in the spectral energy distribution (SED) of the source, reported in a previous work, which the authors linked to the optically thin synchrotron emission of a jet. We then present a study performed on the transitional millisecond pulsar PSR J1023+0038 during quiescence. We measured a linear polarization of 1.09 ± 0.27% and 0.90 ± 0.17% in the V and R bands, respectively. The phase-resolved polarimetric curve of the source in the R-band reveals a hint of a sinusoidal modulation at the source orbital period. The NIR -optical SED of the system did not suggest the presence of a jet. We conclude that the optical linear polarization observed for PSR J1023+0038 is possibly due to Thomson scattering with electrons in the disc, as also suggested by the hint of the modulation of the R-band linear polarization at the system orbital period.
Near Retirement Age (≥55 Years) Self-Reported Physical Symptoms and Use of Computers/Mobile Phones at Work and at Leisure
Authors: Korpinen Leena , Pääkkönen Rauno , Gobba Fabriziomaria
Published: October 2017

The aim of this research is to study the symptoms and use of computers/mobile phones of individuals nearing retirement age (≥55 years). A questionnaire was sent to 15,000 Finns (aged 18–65). People who were ≥55 years of age were compared to the rest of the population. Six thousand one hundred and twenty-one persons responded to the questionnaire; 1226 of them were ≥55 years of age. Twenty-four percent of the ≥55-year-old respondents used desktop computers daily for leisure; 47.8% of them frequently experienced symptoms in the neck, and 38.5% in the shoulders. Workers aged ≥55 years had many more physical symptoms than younger people, except with respect to symptoms of the neck. Female daily occupational users of desktop computers had more physical symptoms in the neck. It is essential to take into account that, for people aged ≥55 years, the use of technology can be a sign of wellness. However, physical symptoms in the neck can be associated with the use of computers.
Sphingosine Kinase 1 and Sphingosine-1-Phosphate Signaling in Colorectal Cancer
Authors: Bao Yonghua , Guo Yongchen , Zhang Chenglan , Fan Fenghua , Yang Wancai
Published: October 2017

Sphingosine kinase 1 (Sphk1) is a highly conserved lipid kinase that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P). Growing studies have demonstrated that Sphk1 is overexpressed in various types of solid cancers and can be induced by growth factors, cytokines, and carcinogens, leading to the increase of S1P production. Subsequently, the increased Sphk1/S1P facilitates cancer cell proliferation, mobility, angiogenesis, invasion, and metastasis. Therefore, Sphk1/S1P signaling plays oncogenic roles. This review summarizes the features of Sphk1/S1P signaling and their functions in colorectal cancer cell growth, tumorigenesis, and metastasis, as well as the possible underlying mechanisms.
Least-Squares Solution of Linear Differential Equations
Authors: Mortari Daniele
Published: October 2017

This study shows how to obtain least-squares solutions to initial value problems (IVPs), boundary value problems (BVPs), and multi-value problems (MVPs) for nonhomogeneous linear differential equations (DEs) with nonconstant coefficients of any order. However, without loss of generality, the approach has been applied to second-order DEs. The proposed method has two steps. The first step consists of writing a constrained expression, that has the DE constraints embedded. These kind of expressions are given in terms of a new unknown function, g ( t ) , and they satisfy the constraints, no matter what g ( t ) is. The second step consists of expressing g ( t ) as a linear combination of m independent known basis functions. Specifically, orthogonal polynomials are adopted for the basis functions. This choice requires rewriting the DE and the constraints in terms of a new independent variable, x ∈ [ − 1 , + 1 ] . The procedure leads to a set of linear equations in terms of the unknown coefficients of the basis functions that are then computed by least-squares. Numerical examples are provided to quantify the solutions’ accuracy for IVPs, BVPs and MVPs. In all the examples provided, the least-squares solution is obtained with machine error accuracy.