Effects of elevated temperature on physical and mechanical properties of carbonate rocks in South-Southern Nigeria

Purpose. Limestone and marble are carbonate rocks with several structural and engineering applications. The physical and mechanical properties of the rocks are fundamental as they determine their suitability for various use. Temperature is one of the critical factors that could affect the properties of the rocks and consequently their engineering application. Therefore, a better understanding of how the temperature, especially when it is higher than ambient, will affect the properties of the rocks is essential. In this work, the effects of the elevated temperature on some physical and mechanical properties of the carbonate rocks have been studied. Methods. Cubic samples of the rocks were prepared and heated in a furnace to different temperatures up to 900°C at an interval of 100°C and then cooled to the room temperature for testing. Porosity, dry density and uniaxial compressive strength (UCS) of the samples were determined under the effect of the elevated temperature. The porosity and dry density were determined using the saturation and buoyancy method while the UCS was estimated from the point load index tests performed on the samples. Findings. The results of this work indicate that the elevated temperature has significant effects on the physical and mechanical properties of the rocks. The porosity of the rocks showed an increasing trend as the temperature was increased while the density steadily decreased especially at the temperature above 300°C. The UCS of the rocks also declines with increased temperature but with an intermittent increase in their strength at a specific heating temperature. Originality. Most of the available studies on Nigerian carbonate rocks are focused on the estimation of physical and mechanical properties of the rocks without considering changes in these properties when the rocks are subjected to high temperatures. This study therefore aims to fill the gap by investigating the effects of the elevated temperatures on the physical and mechanical properties of some of the Nigerian carbonate rocks. Practical implications. The results of this study further increase understanding of the effect of high temperature on carbonate rocks, and also help to identify the critical temperature at which the properties of carbonate rocks undergo significant and irreversible changes. This information is very important for restoration of valuable fire-damaged structures made of carbonate rocks.Мета. Вивчення впливу високих температур на фізико-механічні властивості карбонатних порід на основі експериментальних термічних досліджень їх зразків для проектування будівель і споруд, стійких до руйнувань від пожеж. Методика. Кубічні зразки порід нагрівалися в печі до 900°C з інтервалом у 100°C, а потім охолоджувалися до кімнатної температури. Пористість, об’ємна маса в сухому стані, міцність на одноосьовий стиск (МОС) зразків визначалися при різних високих температурах. Пористість та об’ємна маса в сухому стані вимірювалися шляхом визначення насичення й плавучості зразків, у той час як МОС оцінювалася при випробуванні зразків на зосереджене навантаження. Результати. Результати дослідження свідчать про те, що високі температури чинять суттєвий вплив на фізико-механічні властивості карбонатних порід. З підвищенням температури пористість порід має стійку тенденцію до збільшення, а об’ємна маса – до зменшення, особливо при температурах вище 300°C. МОС також в цілому знижується при підвищенні температури, однак при деяких температурах спостерігається тимчасове збільшення міцності. Наукова новизна. Вперше для карбонатних порід Нігерії встановлено характер впливу високих температур на їх фізико-механічні властивості, що раніше не досліджувалось. Дане дослідження проведено з метою заповнення прогалини у вивченні цього питання. Практична значимість. Розширено уявлення щодо впливу високих температур на карбонатні породи та визначено критичні значення температури, при яких їх властивості зазнають суттєвих і незворотніх змін. Ці дані є досить важливими для відновлення значущих споруд із карбонатних порід, які піддалися руйнуванню під час пожежі.Цель. Изучение влияния высоких температур на физико-механические свойства карбонатных пород на основе экспериментальных термических исследований их образцов для проектирования зданий и сооружений, устойчивых к разрушениям от пожаров. Методика. Кубические образцы пород нагревались в печи до 900°C с интервалом в 100°C, а затем охлаждались до комнатной температуры. Пористость, объемная масса в сухом состоянии, прочность на одноосное сжатие (ПОС) образцов определялись при различных высоких температурах. Пористость и объемная масса в сухом состоянии измерялись путем определения насыщения и плавучести образцов, в то время как ПОС оценивалась при испытании образцов на сосредоточенную нагрузку. Результаты. Результаты исследования свидетельствуют о том, что высокие температуры оказывают значительное влияние на физико-механические свойства карбонатных пород. С возрастанием температуры пористость пород имеет устойчивую тенденцию к увеличению, а объемная масса – к уменьшению, особенно при температурах выше 300°C. ПОС также в целом снижается при повышении температуры, однако при некоторых температурах наблюдается временное увеличение прочности. Научная новизна. Впервые для карбонатных пород Нигерии установлен характер влияния высоких температур на их физико-механические свойства, что ранее не исследовалось. Данное исследование проведено для заполнения пробела в изучении этого вопроса. Практическая значимость. Расширены представления о влиянии высоких температур на карбонатные породы и определены критические значения температуры, при которых их свойства претерпевают существенные и необратимые изменения. Эти данные очень важны для восстановления значимых сооружений из карбонатных пород, которые подверглись разрушению при пожаре.The author wish to express his appreciation to Mr. J.O. Ayeni, Mr. M.B. Jamiu, Mr. I.O. Olanrewaju and Mr. T.V. Oluwafemi for their contribution in acquiring the data used for this study

Upaya Meningkatkan Kerjasama Siswa Dalam Pembelajaran Matematika Melalui Model Pembelajaran Tutor Sebaya (PTK Pada Siswa Kelas VIII A Semester Genap SMP Negeri 1 Karangnongko Tahun Ajaran 2012/2013)

Penelitian ini bertujuan untuk meningkatkan kerjasama siswa dalam pembelajaran matematika melalui model pembelajaran tutor sebaya. Jenis penelitian ini adalah penelitian tindakan kelas (PTK). Subjek penerima tindakan adalah siswa kelas VIII A SMP Negeri 1 Karangnongko yang berjumlah 34 siswa dan subjek pelaksana tindakan adalah peneliti dan guru matematika kelas VIII A. Teknik pengumpulan data dilakukan melalui observasi, wawancara, metode tes, catatan lapangan, dan dokumentasi. Teknik analisis data dilakukan secara deskriptif kualitatif dengan metode alur yang terdiri dari pengumpulan data, reduksi data, penyajian data, dan penarikan kesimpulan. Hasil penelitian menunjukkan bahwa adanya peningkatan kerjasama siswa dalam pembelajaran matematika melalui model pembelajaran tutor sebaya. Hal ini dapat dilihat dari indikator yang meliputi 1) keterlibatan dalam kerja kelompok sebelum tindakan 35,29% dan setelah tindakan 70,59%, 2) tanggungjawab dalam kerja kelompok sebelum tindakan 29,41% dan setelah tindakan 64,70%, dan 3) kepercayaan dalam kerja kelompok sebelum tindakan 17,65% dan setelah tindakan 58,82%. Kesimpulan penelitian ini adalah bahwa model pembelajaran tutor sebaya dapat meningkatkan kerjasama siswa dalam pembelajaran matematika

Peningkatan Kemampuan Komunikasi Siswa dalam Pembelajaran Matematika melalui Pendekatan Induktif(PTK Pada SiswakKelas VII Smp Negeri 1 Grogol Semester Ganjil Tahun 2016/2017)

This study aims to increase students' mathematical communication skills through an inductive approach. This type of research is a classroom action research. The subject of this research is the Mathematics teacher of SMP Negeri 1 Grogol as the actor and the students of class VII D as the subject of the recipient of action with the number of 32 students. The implementation of class action is done during two cycles four times meetings. Data collection techniques carried out with observation, documentation, test methods and field notes. To ensure the validity of data used triangulation of sources and techniques. Data analysis techniques used are data reduction, data presentation and data verification . The result of the research shows the improvement of students' communication ability in the mathematics learning using the inductive approach seen from the percentage: (1) Students are able to solve mathematical problems from 15.62% to 78.12%; (2) Students are able to ask questions from 18.72% to 65.62%; (3) Students able to propose ideas / ideas from 28.12% increased to 71.87%; (4) Students able to present the discussion result from 9.37% to 62.50%. It can be concluded that the application of an inductive approach in mathematics learning can improve students' communication skills Keywords: Reasoning, Inductive Approach, Mathematics Learnin

Peningkatan Keaktifan Siswa Dalam Pembelajaran Matematika Melalui Model Pembelajaran Accelerated Learning Tipe Somatis, Auditori, Visual, Dan Intelektual Pokok Bahasan Lingkaran(PTK pembelajaran matematika kelas VIII D MTs Negeri Surakarta 1 Semester 2 Tahun Pelajaran 2017/2018)

The objective of the research is to describe the increase of students’ activeness in Mathematics through Accelerated Learning Model with Somatic, Auditory, Visual, and Intellectual types in the academic year of 2017/2018. The design of this research is classroom action research. The data is collected by using observation, field note, and documentation method. To analyze the data, the reseacher uses three methods such as data reduction, data presentation, and data verification. The researcher uses triangulation method for the data validity. The findings show that the students’ activeness is rising, as follows: (1) In the first condition, the willingness of students who answer some questions is about 10,52%, then it raises to be 71,05%. (2) In the first condition, the willingness of students who ask some questions is about 7,89% and it increases to be 76,32%. (3) In the first condition, the willingness of students who finish some questions in front of the class is 0% and surprisingly, it becomes 65,79% after using the learning model. Based on the description, it can be concluded that applying Accelerated Learning model with Somatic, Auditory, Visual, and Intellectual types can improve the students’ activeness

Peningkatan Komunikasi Dan Hasil Belajar Matematika Dengan Strategi Card Sort (PTK Pembelajaran Matematika Siswa Kelas VIII B Semester Ganjil SMP N 3 Satu Atap Grobogan 2013/2014)

Tujuan penelitian ini adalah untuk meningkatkan komunikasi dan hasil belajar matematika siswa kelas VIII B SMP Negeri 3 Satu Atap Grobogan pada materi relasi dan fungsi melalui strategi Card Sort. Jenis penelitian ini PTK kolaboratif. Subyek penelitian yang dikenai tindakan adalah siswa kelas VIII B SMP Negeri 3 Satu Atap Grobogan, yang berjumlah 24 siswa. Metode pengumpulan data melalui metode observasi, tes, catatan lapangan dan dokumentasi. Teknik analisis data secara deskriptif kualitatif dengan metode alur. Keabsahan data dilakukan dengan observasi secara terus menerus dan triangulasi data. Hasil penelitian ini: (1) Terdapat peningkatan komunikasi dilihat dari meningkatnya indikator komunikasi meliputi: a) Menjawab pertanyaan sebelum tindakan 12,5% dan di akhiri dengan tindakan sebesar 52,2%, b) Mengkomunikasikan gagasan dengan simbol atau tabel sebelum tindakan 16,7% dan di akhiri dengan tindakan sebesar 65,2%, (c) Kerja sama dalam kelompok sebelum tindakan 25% dan di akhiri dengan tindakan sebesar 78,3%. (2) Hasil belajar siswa yang mencapai KKM sebelum dilakukan tindakan sebesar 29,2% dan di akhiri dengan tindakan sebesar 91,3%. Kesimpulan penelitian ini adalah penerapan strategi Card Sort dalam pembelajaran dapat meningkatkan komunikasi dan hasil belajar

Komparasi Hasil Belajar Matematika Dengan Strategi Teams Games Tournament (TGT) Dan Snowball Throwing (ST) Ditinjau Dari Gaya Belajar Siswa Kelas VIII SMP Negeri 2 Sawit Tahun Ajaran 2017/2018

In this research aims to (1) Describe the influence of Teams Games Tournament and Snowball Throwing Learning strategy toward student learning outcomes in mathematics, (2) Describe the influence of learning style toward student learning outcomes in mathematics, (3) Describe the interaction between learning strategy and learning style toward student learning outcomes in mathematics. The type of the research is quantitative research with quasi experimental. The population of the research was all students of VIII Grade at SMP Negeri 2 sawit. The research sample consisted of two classes. The technique of collecting data with methods of test, questionnaire, and documentation. The technique of analyzed data using the unbalanced two-way analysis of variance. The finding of the research with α = 5% (1) There is influence of Teams Games Tournament and Snowball Throwing strategy toward student learning outcomes in mathematics, (2) There is no effect of learning styles toward student learning outcomes in mathematics, (3) There is no effect interaction between learning strategy and learning Styles toward student learning outcomes in mathematics

Hubungan Model Pembelajaran Team Assisted Individualization Dengan Prestasi Belajar Ditinjau Dari Taksonomi Bloom

The purpose of this study is to analysis and examine of influence of Team Assisted Individualization (TAI) and Expository learning model toward matematic learning achievement. This study type is quantitative experiment study. Population in this study are 200 students of 7th grade in the academic year of 2014/2015, sample of this study consist of two different classes, there are VII E as control class and VII F as experiment class. Sampling technique used is cluster random sampling. Method of data collection used is result test of mathematic learning and documentation method. Data analysis method used in this study is chi square test. From the study result, concluded that there is influence of Team Assisted Individualization and expository learning model toward learning achievement, with chi square of Team Assisted Individualization (TAI) result is 95.4767 and chi square of Expository result is 74.7925

Peningkatan Kreativitas Siswa Pada Pembelajaran Matematika Melalui Pendekatan Open-Ended(PTK di kelas VII Semester Ganjil SMP Negeri 1 Sambi Tahun Ajaran 2015/2016)

This research aims to improve student’s creativity in mathematics learning through the Open-Ended approach. This research is a classroom action research. The subject recipient of this research are students of class VII B SMP Negeri 1 Sambi while implementing measures subject is math teacher. The implementation of actions research carried out for two cycles of four meetings. The techniques of collecting data was through observation, documentation, test methods, and field notes. To ensure the validity of data used triangulation sources and techniques. Techniques of analysis data using data reduction, data presesntation, and verification of data. The results of the research shows that there are increasing of student creativity on mathematics learning through Open-Ended approach seen from the percentage of: 1) students often ask good questions and weighs from 18.75% increase to 75.00%; 2) the student is able to express an opinion spontaneously and are not shy from 25% increase to 78.13%; 3) the student is able to apply for thinking, problem-solving ideas different from others from 15.63% increased to 71.88%. It can be concluded that the application of the Open-Ended approach to the study of mathematics can improve students’ creativity

Pengembangan Bahan Ajar Matematika Berbasis Pendidikan Nilai Islam Pada Pokok Bahasan Himpunan Di Mts Negeri Mlinjon Klaten

This research is a development research that aims to: (1) develop Mathematics Teaching Materials Based on Islamic Values Education for MTs, (2) examine the quality of Mathematics Teaching Materials Based on Islamic Values Education that developed, and (3) examine the response of students to the teaching materials and the mathematics learning based on islamic values education. Validation is done by two lecturers and one math teacher to examine the quality of teaching materials and to obtain suggestions for the improvement. Response of students obtained by use of the questionnaire. The results of the research and development are: (1) Mathematics Teaching Materials Based on Islamic Values Education for subject of Set. The development procedure includes the preliminary phase, development phase and testing phase. (2) based on the assessment of the three validators, quality of Mathematics Teaching Materials Based on Islamic Values Education classified categories Very Good with the ideals percentage 85,33%, (3) the response of students to the teaching materials and the mathematics learning based on islamic values education classified categories High with an average of ideals percentage 79,61%