Masalah Pembelajaran Pembuktian Matematika Bagi Mahasiswa di Indonesia

Mathematical proof is important for mathematical student at college, but many mathematical student at Indonesian college can't learn mathematical proof well. They feel that mathematical proof is so difficult. The research is focused on looking for the answer of the question “ why Indonesian mathematical college student can't learn mathematical proof well?” and “what is the solution?”. The effort to answer the question have be reported on Indra Siregar's article in 2015 with the title “Mathematical proof learning for beginner”, but the researcher found some new information based on the data in that article. The reseacher found that Indonesian mathematical college student can't learn mathematical proof well not only caused by bad logical mathematic ability and the lack of sources books for beginner, but the lack of experience on handling nonroutine mathematical problem. We have two kinds of solution to solve the problems, that is shortterm solution and long-term solution

STUDI KOMPARASI HASIL BELAJAR SISWA YANG MENGGUNAKAN MODEL PEMBELAJARAN PROBLEM BASED LEARNING DENGAN DISCOVERY LEARNING PADA MATA PELAJARAN AKUNTANSI DI SMK NEGERI 2 NGANJUK

Penelitian ini bertujuan untuk mengetahui perbandingan hasil belajar siswa yang menggunakan model pembelajaran Problem Based Learning dengan Discovery Learning pada mata pelajaran akuntansi. Metode yang digunakan dalam penelitian ini adalah jenis true experiment design menggunakan desain Pretest Postest Control Group Design dimana terdapat kelas eksperimen dengan model pembelajaran Discovery Learning dan kelas kontrol dengan model pembelajaran Problem Based Learning  yang selanjutnya diberikan posttest untuk mengetahui hasil belajar siswa setelah diberikan perlakuan yang berbeda. Tempat penelitian ini adalah di SMK Negeri 2 Nganjuk sedangkan subjek yang diteliti adalah siswa kelas X prodi Akuntansi. Kelas yang digunakan dalam penelitian ini adalah kelas X AK 1 sebagai kelas eksperimen dan X AK 4 sebagi kelas kontrol, dengan jumlah siswa kedua kelas tersebut sebesar 34 siswa. Dari hasil penelitian yang diperoleh menunjukkan bahwa hasil belajar siswa dengan model pembelajaran Discovery Learning lebih tinggi dari hasil belajar siswa dengan model pembelajaran Problem Based Learning dengan nilai rata-rata kelas eksperimen 91,17 dan nilai rata-rata kelas kontrol 85,29. Hasil uji hipotesis dengan menggunakan uji independent sample t-test menunjukan hasil sebesar 0,026 atau kurang dari 0,05. Hasil tersebut menunjukan taraf signifikan kurang dari 0,05 sehingga Ho ditolak dan Ha diterima ini berarti terdapat perbedaan hasil belajar antara kelas yang menggunakan model pembelajaran Discovery Learning dengan Problem Based Learning. Kata Kunci: Problem Based Learning, Discovery Learning, Hasil Belaja

PENGARUH DAU, DAK, PAD DAN PERTUMBUHAN EKONOMI TERHADAP BELANJA MODAL

Tujuan dari penelitian ini untuk mengetahui pengaruh Dana Alokasi Umum, Dana Alokasi Khusus, Pendapatan Asli Daerah dan Pertumbuhan Ekonomi pada belanja modal provinsi jawa barat, periode waktu penelitian yang digunakan selama  6 tahun mulai dari tahun 2015 sampai 2020. Populasi penelitian ini meliputi seluruh kabupaten/kota provinsi jawa barat periode 2015-2020, Teknik pengambilan sampel menggunakan purposive sampling berdasarkan kriteria yang telah ditetapkan diperoleh 10 kabupaten/kota. jenis data yang digunakan adalah data sekunder yang diperoleh dari situs DJPK dan BPS. metode analisis yang digunakan dalam penelitian ini menggunakan metode analisis regresi data panel. Hasil penelitian menunjukan bahwa variabel dana alokasi umum berpengaruh terhadap belanja modal, sementara dana alokasi khusus, pendapatan asli daerah dan pertumbuhan ekonomi secara bersamaan tidak berpengaruh terhadap belanja modal.

Hypertensive Crises in the Adolescent: Evaluation of Suspected Renovascular Hypertension

Hypertensive crises can be divided into two categories as hypertensive emergency and hypertensive urgency. Most authorities have defined hypertensive emergency as a situation that requires immediate reduction in blood pressure (BP) with parenteral agents because of acute or progressive target organ damage, whereas hypertensive urgency is a situation with markedly elevated BP but without severe symptoms or progressive target organ damage, wherein the BP should be reduced within hours, often with oral agents. Adolescent with hypertension should be suspected of having renovascular hypertension in spite of other causes. This case is presenting a 16-year-old boy with hypertensive crises due to suspected renovascular hypertension. His blood pressure was 240/120 at admission with hypertensive retinopathy grade III and there was increase in creatinine after administering ACE-inhibitor but his renal arteriography revealed normal, other physical examination and laboratory findings was normal. Regarding these findings, the conclusion was this patient got essential hypertension. As many hypertensive crises occur in any ages, clinicians should aware the possibility of renovascular hypertension in young patients with hypertensive crises. An early detection and urgent treatment are needed to prevent the implication of progressive target organ damage.Key words: hypertensive crises, adolescent

PENGARUH KUALITAS BATU BARA TERHADAP EFISIENSI BOILER UNIT UTILITAS BATU BARA PT PETROKIMIA GRESIK MENGGUNAKAN METODE INDIRECT/ HEAT LOSS MENGACU PADA ASME

PT Petrokimia Gresik in producing organic and non-organic fertilizers uses several energy sources, one of which is the Coal Utility Unit (UBB) located at PT Petrokimia Gresik's factory III. In the UBB unit, there is a Steam Power Plant (PLTU) with a power generation capacity of up to 32 MW (Net 25 MW). One of the main pieces of equipment in a PLTU is a boiler which is used to convert water into pressurized steam by means of heating from burning fuel in the combustion chamber. The fuel used in the UBB unit is coal. To meet the needs for electricity and steam at PT Petrokimia Gresik, boiler performance is paid close attention to both in terms of fuel and operating parameters so that it remains efficient, using the ASME PTC 4 reference. This study analyzes the quality of coal in the form of HHV values on boiler efficiency in units UBB PT Petrokimia Gresik using the heat loss/indirect method, the purpose of this study is to determine the effect of coal quality in the form of HHV values on boiler efficiency. The coal used has HHV values of 4,995 kcal/kg, 4,993 kcal/kg, and 4,986 kcal/kg. From the boiler efficiency calculations referring to ASME PTC 4 with operational data, boiler specifications, and coal content data, the results show that the calorific value of coal affects boiler efficiency. The highest boiler efficiency results were 87.03% at HHV 4,995 kcal/kg and the smallest efficiency was 85.62% at HHV 4,993 kcal/kg, with the biggest heat loss factor affecting coal efficiency due to dry flue gas, moisture from burning H2, and moisture from the fuel.  Keywords: PLTU, boiler, coal, efficiency, heat loss

PENGARUH PERBEDAAN SUDUT PADA KATUP BUANG DAN KETINGGIAN PIPA OUTPUT TERHADAP KINERJA POMPA HIDRAM

Air merupakan salah satu faktor sumber yang sangat penting dan dibutuhkan dalam kehidupan sehari-hari terutama manusia, hewan dan tumbuhan. Untuk memindahkan air dari sumber menuju tempat yang diinginkan dibutuhkan sebuah alat yaitu pompa air. Dalam pengoperasiannya pompa air membutuhkan energi listrik atau bahan bakar minyak. Kebutuhan bahan bakar minyak yang semakin meningkat mengakibatkan bahan bakar minyak semakin langka dan mahal, sehingga diperlukan solusi dari permasalahan ini. Salah satu solusinya adalah pompa hidram. Teknik analisa data dalam penelitian ini menggunakan analisis data statistika deskriptif kuantitatif yaitu menggambarkan hasil penelitian secara grafis dalam tabel dan grafik. Penelitian ini dilakukan untuk mengetahui pengaruh perbedaan sudut pada katup buang dan ketinggian pipa output terhadap kinerja pompa hidram. Pompa hidram yang digunakan dalam penelitian ini berdiameter 2 inch, dengan Panjang inlet 4 m dan diameter pipa discharge 0,5 inch, menggunakan volume tabung udara 0,0056 m3, variasi sudut katup adalah 450, 550, 650, dan 750. Hasil penelitian ini diperoleh bahwa pada perancangan pompa hidram didapatkan hasil yang paling optimal adalah pada sudut 450 dengan ketinggian discharge 5 m, volume tabung udara 0,0056 m3. Dengan kapasitas discharge 1,6 10-4, efisiensi pompa hidram 22,33% sedangkan efisiensi terendah yaitu pada sudut katup 750 dengan nilai efisiensi 16,30% dan kapasitas discharge 1,6 x 10-4. Kata Kunci: Pompa Hidram, Sudut Katup, Tinggi Output, Efisiensi

PENGARUH LAJU ALIRAN UDARA TERHADAP KUALITAS NYALA API DAN EFISIENSI KOMPOR GASIFIKASI BIOMASSA TIPE UPDRAFT DENGAN BAHAN BAKAR TEMPURUNG KELAPA

Coconut shell is one of the biomasses that has the potential to produce energy. One alternative technology for household scale, especially in rural areas with the above conditions is a biomass gasification stove by utilising coconut shells as stove fuel. Gasification is a thermochemical conversion with heat that can convert dry biomass into gaseous fuel by regulating the air pressure in the gasifier. The amount of air entering the gasifier will affect the mass flow rate of syn-gas and the quality of syn-gas. This research was conducted with a quantitative descriptive experimental method which aims to determine the effect of the updraft type gasifier inflow rate on flame temperature, flame height and width, flame duration, flame colour, effective flame length, stove thermal efficiency, and power produced by the biomass gasification stove. In this study using variations in air flow rates of 6 m / s, 8 m / s, and 10 m / s. The results of the study obtained the highest average flame temperature obtained from 10 m / s air flow which is 925 ° C. The more flammable gas content in syngas will increase the flame temperature. The longest flame duration was 22 minutes at 6 m/s air flow. The highest flame height and width were 60 cm with a flame width of 16 cm at 10 m/s air flow. The colour of the flame produced in all variations was orange. The best effective flame duration of the 10 m/s air flow rate is 8.71 minutes. The largest thermal efficiency results were obtained at an air flow of 10 m/s, namely 3.31%. And the highest power value at 10 m/s air flow is 105.8 kW.  Keywords: coconut shell, biomass gasification stoves, air flow rate, flame quality, thermal efficiency

PENGARUH DIAMETER LUBANG NOZZLE SPRAY WATER PADA REACTOR TRAPPING GASIFIKASI BIOMASSA TEMPURUNG KELAPA TERHADAP KUALITAS NYALA API DAN KUANTITAS FLAMMABLE SYNGAS

Biomassa adalah bahan organik yang dihasilkan melalui proses fotosintesis, baik berupa produk maupun buatan. Biomassa tempurung kelapa dapat dimanfaatkan lebih optimal, yaitu sebagai sumber energi alternatif dengan cara gasifikasi. Gasifikasi adalah suatu proses konversi bahan bakar padat (biomassa)menjadi syngas. Proses gasifikasi terdiri dari beberapa peralatan utama, yaitu gasifier, blower, cyclone, dan reactor trapping. Reactor trapping berfungsi sebagai penyaring akhir syngas dengan menggunakan air melalui nozzle spray water, agar syngas yang dihasilkan lebih bersih. Penelitian ini bertujuan untuk mengetahui pengaruh diameter lubang nozzle spray water terhadap kualitas nyala api dan kuantitas flammable syngas dengan cara membakar syngas yang keluar dari burner. Jenis penelitian ini adalah penelitian eksperimen. Vairabel bebas pada penelitian ini yaitu diameter lubang nozzle spray water pada reactor trapping sebesar 0,4 mm, 0,3 mm, dan 0,2 mm, sedangkan variabel terikatnya adalah tinggi nyala api, temperatur nyala api, visualisasi warna nyala api, dan kuantitas flammable syngas (H2, CO, dan CH4). Instrumen penelitian yang digunakan yaitu timbangan, anemometer, box acrylyc, thermocouple, thermocontrol, kamera, dan kromatografi gas. Hasil penelitian menunjukkan bahwa tinggi nyala api pada diameter lubang nozzle spray water 0,4 mm, 0,3 mm, dan 0,2 mm masing-masing sebesar 23 cm; 23 cm; dan 24 cm; rata-rata temperatur nyala api masing-masing sebesar 471°C; 504°C; dan 534°C; visualisasi warna nyala api secara keseluruhan berwarna jingga; dan hasil kuantitas flammable syngas (H2, CO, dan CH4) masing-masing dengan total sebesar 22,16%; 22,87%; dan 23,62

PENGARUH JUMLAH LILITAN PIPA KONDENSOR TERHADAP KUANTITAS MINYAK PIROLISIS SAMPAH PLASTIK

The large use of plastic in everyday life will certainly have an impact on the environment. One of the methods of processing this plastic waste is by pyrolysis method. In the pyrolysis process there is a condensation process. The condensation process is a process where when saturated steam comes into contact with a surface with a low temperature, there will be a process of heat release from a system that causes the vapor to turn into liquid. The component in charge of this condensation process is referred to as a condenser. The geometric shape of the condenser will affect the heat transfer process that occurs in the condenser. The purpose of this study is to determine the effect of the number of windings in the condenser pipe on the effectiveness of the condenser, distillation efficiency, technical efficiency as well as the quantity of oil produced during the pyrolysis process. This study uses an experimental method where this research will later vary the number of windings of condenser pipes with the number of windings of 5, the number of windings of 7 and the number of windings of 10 to determine the value of condenser effectiveness, distillation efficiency, technical efficiency and quantity of oil produced from each variation and which variation is more optimal The highest oil yield is found in variiation 3 with a total of 10 windings, which is 148 grams, while in variations 1 and 2, each of them only gets 75 grams and 110 grams of oil. The effectiveness of the condenser also increases along with the increase in the number of windings in the condenser pipe, namely for variation 1 by 16%, variation 2 by 62% and variation 3 by 76%. In addition, Distillation efficiency and technical efficiency also increase as the number of windings in the condenser pipe increases. The most results were obtained in variation 3 with the number of windings of 10 with a distillation efficiency of 90% and a technical efficiency of 12%.  Keywords : Plastic, Condenser, number of pipe windings, pyrolysis oi