Multi-mode adaptive-pitch propeller and its application prospects for ships with variable running conditions

Object and purpose of research. This paper describes multi-mode adaptive-pitch propeller and its hydrodynamics. Based on the calculation data, the study demonstrates that this kind of propeller might be quite promising in terms of propulsion performance for the ships with variable running conditions, like patrol vessels that switch between patrol and chase running mode. More-over, multi-mode adaptive pitch propellers may work as two-positional CPPs commonly regarded as general-use propellers. These results might be useful in design of ships for various applications. Materials and methods. Experimental data on hydrodynamic parameters of multi-mode adaptive pitch propeller and design calculation results for a virtual triple-shaft patrol vessel. Main results. The results of this study could be useful in propeller selection for given ship design. Conclusion. It is shown that, as compared to FPPs, multi-mode adaptive pitch propellers are more efficient in terms of propulsion performance.

TRIBOLOGICAL CHARACTERISTICS OF ‘STEEL – CERAMICS-IRRADIATED-BY-HELIUM-IONS’ PAIR

Facility for the tribological characteristics studying of a metal – ceramics pair and parameters of ceramic samples irradiation on the helium ions linear accelerator with energies 0.12 and 4 MeV are resulted. Profiles of damageability and occurrence of target atoms along of helium ions range are calculated for the irradiated TiO2 and Al2O3. Sputtering ratios and dependence of the sputtered atoms quantity on samples thickness are received. Calculations on density change of the irradiated samples are made. Experimental results of a sliding friction factor measurement depending on cycle’s quantity, temperature and irradiation doses are presented. On the basis of microscopic researches and calculation data conclusions are drawn about irradiation influence on interacting pair’s tribological characteristics.

KALKULACIJA PROIZVODNJE KRUŠKE SORTE VILJAMOVKA NA PORODIČNOM GAZDINSTVU

The paper presents calculation of production of Viljamovka pear on family farm in area of the village Kriva Reka near the municipality of Gornji Milanovac. The orchard is in the phase of full fertility and was raised in 2009, on area of 1ha. For the purposes of making the calculation data from 2018 was used, and represent average year during period of full fertility of the orchard. Used the gross margin calculation, the costs incurred were analyzed achieved economic results and the cost price of a pear in the production year.

Calculation of Stress-Strain State and Contact Stresses in the Process of Chip Formation

The reported paper presents a field pattern of sliding lines in a plastic zone of flow chip formation in the process of cutting metals considered for front and rear angles on the cutting blade other than zero. Equations of sliding lines for these conditions are proposed. Using calculation data, plasticity zone border lines are plotted for positive and negative front angles. The paper suggests methods and calculation data on average stress and plane stress state components in nodal points of the plastic zone of chip formation. The study provides data for plotting distribution diagrams of normal and tangential stresses of contact stresses on work surfaces of a cutting blade.

Perbandingan Perhitungan Luas Tanah antara Metode Trilaterasi Segitiga dengan Metode Koordinat

Kesadaran pemilik lahan untuk melindungi status kepemilikannya terhadap ketidakcocokan keadaan bidang tanah lapangan dengan data yang ada di dokumen sertifikat mengakibatkan meningkatnya kebutuhan pengukuran ulang lahan. Penggunaan alat dengan akurasi rendah dan metode yang kurang tepat menyebabkan data luas lahan yang dihasilkan menjadi kurang akurat. Hal ini menyebabkan kebingungan pada pemilik lahan maupun pemilik lahan disekitarnya. Sehingga perlunya data pembanding antara dua alat ukur berbeda dengan metode berbeda untuk memperkaya data perhitungan luas tersebut. Tujuan penelitian ini adalah menghitung luas lahan Gedung Pejuang Veteran Banjarmasin dengan Metode Trilaterasi (pendekatan luasan segitiga dengan ketiga sisi diketahui) menggunakan Pesawat Penyipat Datar (PPD) dan dengan Metode Koordinat menggunakan GPS. Hasil perhitungan tersebut akan dibandingkan dengan data resmi luas lahan yang diperoleh dari BPN. Pengukuran dengan PPD diperoleh luasan sebesar 10.025,476 M2 dan dengan GPS sebesar 10.100,720 M2 dimana luas resmi lahan adalah 11.183 M2. Sehingga diperoleh persentase terhadap luas resmi berturut-turut sebesar 89,65 % dengan pengukuran menggunakan PPD dan sebesar 90,32 % dengan pengukuran menggunakan GPS. Berdasarkan hasil diatas, penggunaan kedua alat tersebut kurang disarankan untuk pengukuran luas lahan secara teliti serta perlunya memastikan batas tanah akurat di lapangan sebelum pengukuran. Abstract The awareness of land owners to protect their ownership status against the mismatch condition between land percil and the data in the documents resulted the increasing need for land re-measurement. Using tools with low accuracy and improper methods causes the result of land area data less accurated. This causes confusion among land owner and its nearby. The data comparisons are needed between two different measuring instruments with different methods to enrich the area calculation data its self. This research aims to calculate the land area of ​​the Pejuang Veteran Banjarmasin Building with the Trilateration Method using an Automatic Level and the Coordinate Method using GPS. The results of these calculations will be compared with official land area data obtained from National Land Agency. Measurement with Automatic Level obtained an area of 10.025,476 M2 and with GPS is 10.100,720 M2 where the official land area is 11.183 M2. The percentage amount between the official area versus Automatic Level and GPS consecutively are 89,65 % and 90,32 %. Based on that results, the use of these tools is less recommended to detailed land measurement and its important to ensure accurate percil boundaries in the field before measurement.

IMPLEMENTASI METODE SAVING MATRIX PADA SISTEM INFORMASI DISTRIBUSI BARANG

Distribution of goods becomes a separate priority within a company, especially with regard to distribution routes. This condition will become complex if there are many branches in the process of distributing goods. For this reason, in this research, calculations were carried out in the process of travelling in distributing goods. To perform these calculations, a method is used, namely the saving matrix method. To carry out this implementation, a goods distribution information system is created with calculations in the distribution of goods using a saving matrix. The results of the research are in the form of information systems developed with a waterfall model with features ranging from processing goods data, customer data, demand data, shipping data, route data and saving matrix calculation data. From the resulting information system, it can also be seen clearly the distance travelled in the distribution of goods so that it can easily determine travel facilities for deliverymen. Distribusi barang menjadi prioritas tersendiri di dalam sebuah perusahaan terutama berkaitan dengan rute distribusi. Konidisi tersebut akan menjadi komplek jika terdapat banyak cabang dalam proses distribusi barang. Untuk itu di dalam peneltian ini dilakukan dilakukan perhitungan dalam proses perjalanan dalam melakukan distribusi barang. Untuk melakukan perhitungan tersebut digunakan sebuah metode yaitu método saving matrix. Untuk melakukan implementasi tersebut maka dibuat sebuah sistema informasi distribusi barang dengan dilengkapi perhitungan dalam distribusi barang dengan saving matrix. Hasil dari penelitian berupa sistema informasi yang dikembangkan dengan waterfall model dengan fitur mulai dari pengolahan data barang, data pelanggan, data permintaan, data pengiriman, data rute dan data peritungan saving matrix. Dari sistema informasi yang dihasilkan juga dapat diketahui dengan jelas jarak tempuh dalam distribusi barang sehingga dapat dengan mudah dalam menentukan fasilitas perjalanan bagi pengantar barang.

ANALISIS PENGARUH VIBRASI TERHADAP PERFORMA BOILER FEEDWATER PUMP (BFP) 3B PLTU ASAM ASAM

Pada Desember 2016 hingga Januari 2017, terjadi penurunan kinerja PLTU Asam Asam Unit 3 yang signifikan dalam penyediaan tenaga listrik. Hal ini dikarenakan adanya permasalahan pada Boiler Feedwater Pump (BFP) 3B. Kemudian masalah harus diselesaikan oleh Turbin dan Kru Pemeliharaan Tambahan dengan beberapa perbaikan. Perbaikan BFP 3B berada pada masalah jarak jalan internal dan masalah poros tekuk. Setelah diperbaiki, data perhitungan menunjukkan bahwa efisiensi total pompa meningkat sebesar 10%, dan zona getaran berpindah dari zona D (berbahaya) ke zona A (aman untuk pengoperasian berkelanjutan). In December 2016 until January 2017, there was a significant decreasing performance of Unit 3 PLTU Asam Asam in supplying electric power. This was because of some problems in Boiler Feedwater Pump (BFP) 3B. Then the problems have to be solved by the Turbine and Auxiliary Maintenance Crew by some repairs. The repair of BFP 3B are in the internal running clearance problem and bending shaft problem. After the repair of them, calculation data show that the pump total efficiency increasing by 10 %, and the vibration zone move from D zone (dangerous) to A zone (safe for continuous operation).