Journal of Mathematical and Fundamental Sciences
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Beberapa Tjatatan Mengenai Roket
No full textIchtisar. Dalam karangan ini didjelaskan beberapa persamaan untuk roket ideal. Dalam roket ideal ini termasuk roket jang pengurangan bahan bakarnja tiap waktu adalah konstan dan roket jang gaja dorongnja konstan dalam segala keadaan tekanan udarannja statis dan ketinggian roket dari permukaan air laut. Abstract. In this paper some equations for idealized rockets are discussed. This type of rockets include those which rate of mass-change is constant and those which thrust is constant in any kind of condition of static pressure and altitude
Active Fractions of Black Rice Bran cv Cempo Ireng Inducing Apoptosis and S-phase Cell Cycle Arrest in T47D Breast Cancer Cells
Get PDFIndonesian black rice cv Cempo Ireng was evaluated for cancer prevention using a T47D cell line model. Methanolic extract of black rice bran (BRB) showed cytotoxicity with an IC50 of 522.13 µg/ml. This result was in contrast to water extract of BRB, which yielded an IC50 of more than 6000 µg/ml. From the methanolic extract of BRB, its 6 fractions were found from the preparative TLC performance, with Rf values ranging from 0 to 0.97. According to the MTT assay of all fractions, fraction 3 (F3) had the lowest IC50 (60.17 ± 1.72µg/ml), while fraction 2 (F2) had an IC50 of 64.3 ± 0.61µg/ml. However, F2 showed the highest induction of apoptosis, i.e. about 75.39 ± 0.43% compared to the T47D cells without treatment (control) (about 8.39 ± 0.16%) and with doxorubicin treatment (about 41.30 ± 0.08%). Furthermore, fraction 5 (F5) not only induced apoptosis but also increased the S-phase arrest percentage (60.36 ± 2.07%), which was significantly higher than for the other treatments. Therefore, each fraction of BRB showed different cytotoxic responses to T47D cells
Antimicrobial, Antioxidant and Cytotoxic Potential of Aerial Parts of Monotheca buxifolia
Get PDFIn this study, different aerial parts of Monotheca Buxifolia were screened for their antibacterial, antifungal, and anti-oxidant activity. Extract of the fruit was most active against P. mirabilis, MSSA and M. morganii strains. Moreover, the methanolic fruit extract demonstrated good antibacterial properties against VRSA, S. aureus and Acinetobacter. Despite having good antibacterial properties, Monotheca buxifolia showed low antifungal activity. The cytotoxic activity was the highest in the pet-ether fruit extract, causing 60% of lethality against Artemia salina larvae with LD50 at 3.307. The highest scavenging activity was shown by the methanolic leaf extract in a concentration-dependent pattern. The findings of this study suggest that Monotheca Buxifolia has good antibacterial, antioxidant potential but low antifungal properties
Gravity Inversion of Talwani Model using Very Fast Simulated Annealing
Get PDFGlobal approaches for estimating geophysical model parameters have been proposed by several authors, including their application for gravity interpretation, which is currently limited to simple and fixed geometrical problems. This paper proposes implementation of Very Fast Simulated Annealing (VFSA) in two-dimensional gravity interpretation problems, which are still rarely addressed. The modeling domain was divided into smaller sub-domains and gravity anomaly calculation was carried out based on the Talwani formulation. To improve the uniqueness of the solution of under-determined problems, specific constraints were added in addition to the assumed known symmetry axes. The inversion of VFSA was tested on synthetic data generated by simple models and on previously published real data to evaluate the applicability of the proposed approach to the interpretation of field data
Study of Nonlinear Periodic Optical System
Get PDFWe give a brief review of some results of our study on one-dimensional shallow nonlinear Bragg grating with nonlinear modulation and deep nonlinear Bragg grating
Effect of B-doping on the Crystal Structural and Optical Properties of Zinc Oxide Thin Films for Photonic Devices
Get PDFAbstract. Effect of B-doping B2H6 on the crystal structural and optical properties of zinc oxide (ZnO) thin films has been studied. The crystal orientation of these films were evaluated by X-ray diffraction. It was found that the (110) reflection peak was dominant for all the film and became less pronounced as B2H6 flow rate was increased. The grain size of thin film decreased as B2H6 flow rate was increased. The transmittance in the ultraviolet wavelengths region shifted to higher energy as the B2H6 flow rate was increased. I t was also found that refractive index of ZnO thin films increased as the B2H6 flow rate was further increased. These doping effects should be minimized in order to grow low resistivity ZnO film with excellent optical properties for application to photonic devices. Efek Doping Boron (B) terhadap Struktur Kristal dan Sifat Optik Lapisan Tipis ZnO untuk Divais OptoelektronikSari. Telah dilakukan studi tentang pengaruh doping B2H6 terhadap struktur Kristal dan sifat optic lapisan tipis ZnO. Orientasi kristal lapisan tipisnya dievaluasi dengan difraksi sinar-x. Diperoleh bahwa puncak refleksi (110) mendominasi seluruh film dan berkurang sejalan dengan penambahan laju aliran B2H6. Ukuran butir Kristal dari film juga berkurang sejalan dengan penambahan laju aliran B2H6. Transmitnasi pada daerah panjang gelombang ultra violer bergeser ke arah energy yang lebih tinggi sejalan dengan penambahan laju aliran B2H6. Ditemukan pula bahwa indeks bias lapisan tipis ZnO bertambah sejalan dengan penambahan laju aliran B2H6. Efek-efek doping tersebut harus diminimalkan agar dapat diperoleh lapisan ZnO beresistivitas rendah dengan sifat optik yang baik untuk aplikasi pada divais fotonik.
A New Approach to Analysis of Inverter Currents
No full textIn this paper, a new approach to analysis of the average and rms currents in inverter switching devices and the rms value of the ripple component of inverter input current is presented. The proposed approach is based on the probability with which the inverter switching devices receive ON signals which can be obtained from the average value of the phase-to-dc midpoint voltages. As the knowledge of the exact switching pattern is not required, this approach is especially useful for inverters in which the exact switching patterns can not be predetermined. To show the general applicability of the proposed approach, the expressions for the average and rms currents in switching devices and the rms value of the ripple component of input current of three-phase hysteresis current-controlled and PWM inverters are derived. Experimental results are included to show the validity of the proposed method. Suatu Pendekatan Baru untuk Analisis Arus-arus InverterDalam makalah ini dipresentasikan, suatu pendekatan baru umtuk analisis arus rata-rata dan rms pada komponen-komponen switching inverter dan nilai rms riak arus masukan inverter. Pendekatan yang diusulkan berbasis pada peluang komponen-komponen switching inverter menerima sinyal ON yang didapatkan dari nilai rata-rata tegangan fasa keluaran. Karena pengetahuan detil tentang pola switching inverter tidak diperlukan, metoda yang diusulkan sangat cocok untuk analisis arus-arus pada inverter dengan pola switching yang tidak bisa ditentukan. Untuk menunjukkan luasnya daerah penerapan, persamaan-persamaan arus rata-rata dan rms komponen switching dan nilai rms riak arus masukan dari inverter yang menggunakan pengendali arus jenis hysteresis dan yang menggunakan pengendali PWM diturunkan. Hasil pengukuran disertakan untuk menunjukkan validitas metoda yang diusulkan
Optimisation of Image Interpretability and Geometric Accuracy of Airborne Videography
Get PDFAirborne video images which have several advantages over satellite images and aerial photographs were captured over some selected areas. After they were refined to increase their interpretability, the images were assessed in accordance with the existing map accuracy specifications. Four algorithms of image refinement were tested. These include projective, row duplication, row interpolation and statistical correlation function. Numerous test points were selected on the image and their coordinates were compared to their ground positions. The results suggest that a solid-state video camera can provide images that are sufficiently accurate for medium-scale topographic mapping.Ketelitian Geometrik dan Optimalisasi Tingkat Ketajaman Citra VideoCitra video, yang mempunyai beberapa keuntungan dibandingkan dengan citra satelit dan foto udara, diperoleh dari hasil penerbangan di atas suatu daerah. Setelah citra tersebut direstorasi untuk meningkatkan tingkat ketajamannya, dilakukan proses fotogrametri untuk mengevaluasi tingkat ketelitian geometriknya. Restorasi citra dilakukan secara digital dengan empat macam teknik, yaitu projektif, interpolasi baris, duplikasi baris, dan kolerasi statistic. Evaluasi keteletian geometrik dilakukan dengan membandingkan koordinat sejumlah titik yang diamati pada citra video dengan posisi seharusnya di lapangan. Hasil pengujian mengindikasikan bahwa kamera video dapat digunakan pada pemotretan udara bagi keperluan pemetaan topografi skala menengah
Pengaruh Lima Jenis Jamur Penicillium terhadap Daya Kecambah Gabah
No full textSari. Kadar air merupakan salah satu factor yang dapat menyokong pertumbuhan dan perkembangan jamur pada biji-bijian yang disimpan selain temperature dan kelembababn relatif dari tempat penyimpanan. Akibat pertumbuhan dan perkembangan jamur pada biji-bijian dapat menyebabkan penurunan daya kecambah biji. Penelitian ini melaporkan hasil pengamatan jamur Penicillium chrysogenum, P. islandicum, P. citrinum, P. decumbens dan P. notatum yang berasal/tumbuh pada beras dan gabah tersimpan. Dari hasil analisa statistika selama 3 bulan didapatkan bahwa tidak ada pengaruh pertumbuhan jamur secara nyata terhadap daya kecambah gabah pada kadar air dibawah 14.0%. Abstract. Next to the temperature and relative humidity of the storage house, the moisture content of the grains will influence growth and development of contaminating molds on the stored grains. Growth and development of these molds may result in decrease of seed germination. This paper reports the observed influence of Penicillium chrysogenum, P. islandicum, P. citrinum, P. decumbens and P. notatum growing on stored rice and paddy. Statistical analysis made during 3 months observations showed that at a moisture content of below 14.0%, no obvious influence of mold growth towards seed germination occurred