Journal of Mathematical and Fundamental Sciences
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Tjatatan Mengenai Beberapa Hama Padi dari Indonesia
No full textRingkasan. Dari sedjumlah besar binatang jang berpotensi sebagai hama, hanja terdapat kurang dari sepuluh species jang betul-betul mempunjai arti ekonomi (hama). Penggerek batang (Tryporyza), walang sangit (Leptocirisa) dan tikus (Rattus) merupakan tiga hama utama dari padi. Ketiga hama ini dan hama padi lainnja jang kurang penting terdapat didaerah sawah diseluruh Indonesia. Penggerek batang seringkali mendjadi wabah (outbreaks) terutama didaerah utara dari pulau Djawa. Tikus mendjadi wabah baik didataran rendah maupun didataran tinggi, sedang "outbreaks" dari walang sangit terbatas didaerah utara Djawa Barat. Sebagai patokan dari "outbreaks" dipakai angka kerusakan 5000 IIA tanaman padi. Abstract. There are less than ten important rice crop pests out of a large number of general known pests. Rice stem borers (Tryporyza), rice bugs (Leptocorisa) and field rats (rattus) caused serious damages on rice crops. These three important pests and other less important ones were found at rice fields throughout Indonesia. The outbreaks of rice stem borers occurred at the northern part of Java almost yearly. The outbreaks of field rats were more widespread either at lowland or highland, whereas the outbreaks of the rice bugs were restricted to the northern part of West Java. The adapted value for outbreaks was 5000 HA damages on rice crop
Evaluation of the Spectrophotometric Determination of Zinc with Methylene Blue and Thiocyanate
No full textAbstract. The reaction of zinc with methylene blue and thiocyanate is developed to a highly sensitive spectrophotometric determination of zinc in which the unknown zinc is reacted with methylene blue and thicyanate, giving insoluble complex. This is filtered off and the decrease in the amount of zinc present, is measured. Suitable masking agents prevent interference of most common ions, even when present in large amounts, except with cobalt, copper, cadmium and mercury which do not interfere if present in small amounts only. In simplicity, sensitivity and freedom from interference this method compares favorably with dithizone and zincon methods.Ichtisar. Reaksi seng dengan biru metilena dan tiosianat diperkembangkan mendjadi suatu penentuan spektrofotometris jang sangat pekak untuk seng dalam mana seng itu direaksikan dengan biru metilena dan tiosianat dengan menghasilkan suatu kompleks jang tak larut. Kompleks ini disaring dan berkurangnja djumlah seng diukur. Dengan zat penkompleks jang sesuai dapat dihilangkan gangguan dari kebanjakan ion jang umum terdapat walaupun djumlahnja besar, ketjuali untuk Cobalt, tembaga dan raksa, ion2 mana hanja tidak akan mengganggu kalau djumlahnja ketjil. Ditilik dari segi kesederhanaan, kepekaan dan kebebasan dari gangguan tjara ini menguntungkan djika dibandingkan dengan tjara2 detbezon dan zincon
Generator Pulsa Arus
Get PDFIchtisar. Dalam penjelidikan mengenai karakteristik suatu arrester, selain mengetahui karakteristik tembus terhadap tegangan pulsa djuga perlu diselidiki sifat2 tahanan non linearnja (lazim dipergunakan Si C) terhadap pulsa arus menentukan tegangan tinggalnja (Rest spanning). Untuk kepentingan ini dipergunakan pulsa arus 5 x 10 μ sec ataupun 10 x 20 μ sec. Disini akan dibahas mengenai parameter2 rangkaian dan faktor2 jang penting diperhatikan dalam perentjanaan suatu generator pulsa arus. Abstract. In order to obtain the performance characteristic of an arrester, besides knowing the breakdown voltage of its gaps it is also necessary to know the behaviour of the non linear value element (usually Si C) with respect to current surges to get a picture of its rest voltage. For this purpose 5 x 10 μ sec or 10 x 20 μ sec current surges are used. The circuit parameters, and some important factors concerning the design of a current surges generator are discussed here
Topographic Lineaments in Nusa Barung, East Java
No full textPengukuran kelurusan-kelurusan (lineaments) topografi pada karst batu gamping di Nusa Barung menghasilkan tiga buah maksimum, jaitu jang terarah ke N 5°-10° E, N 35° -40° E, dan N 335° -340° E. Kelurusan-kelurusan topografi itu dipengaruhi oleh rekah-rekah/sesar-sesar. Penjebaran dari maksimum-maksimum mengesankan bahwa rekah-rekah disebabkan oleh tekanan jang terarah N 10° E- S 10° W. Rekah-rekah jang sama arahnja dengan tekanan adalah rekah-rekah tarikan (extension fractures); jang membuat sudut 25° dengan arah tekanan adalah "shear fractures". Tekanan itu tidak menghasilkan perlipatan tetapi memiringkan seluruh Nusa Barung ke selatan sebesar 2°.Hal itu sesuai dengan posisi pulau tersebut pada sajap selatan Geantiklin Djawa
The Banda Geosyncline during Permian Time: A Paleogeographic Synthesis
No full textIn the eastern part of Indonesia a semicular zone known as the Banda Geosyncline coincides with the Outer Banda Arch. This geosynclines persisted from pre-Permian time until the Upper Tertiary. Its maximum extension was attained during Mesozoic time as shown by Mesozoic rocks of the many islands of the arch.The Banda Geosyncline was in existence during Permian time in an area which now occupies the southeastern corner of Indonesia as recorded by Permian rocks found on the islands of Savu, Roti, Timor, Leti, Luang and Babar. Reports of questionable Permian deposits on the islands of Ambon and in the eastern arm of island of Sulawesi (Celebes) may indicate that Permian geosynclines extended even further.Probably the Banda Geosyncline was already in existence in Carboniferous time. Carboniferous fossils are reported from southeastern Indonesia from the island of Leti and in the Tokala Mountains of the eastern arm of Sulawesi. The Carboniferous basin may form the initial stage of the Banda Geosyncline.The Permian Banda Geosyncline bordered a land mass which included the eastern part of Sulawesi, the Sula Spur, southern part of Irian (New Guinea), the Sahul shelf, and extended further to the south into Australia and Tasmania. The trend of geosynclines follows the present geanticlinal ridge of the islands of the Outer Banda Arch. The present Banda Sea apparently was an open sea during the Permian period.The distribution of Permian rocks and overthrust units in Timor suggests that the Permian geosynclines in the southeastern corner of Indonesia was formed by two almost parallel basins, i.e. the Sonnebait-Mutis basin in the north and the Kekneno basin in the south. These two basins trended approximately northeast-southwest parallel with the trend of geosynclines in this part of Indonesia. The basins were separated by a narrow ridge responsible for the different facies of the sediments deposited in the two basins.The neritic volcanic rocks of the Sonnebait and the Mutis overthrust units indicate that the Sonnebait-Mutis depositional basin was deeper than Keknone basinof flysch facies. The rocks of the Kekneno basin were products of erosion and denudation of that part of the Permian land mass to the south. An abundance of fossils in the Sonnebait overthrust unit indicates favourable life conditions. Probably this basin had a good circulation with the open sea to the north, in the vicinity of present Banda Sea,At times volcano ejected tuffs and extruded lavas over the floor of Sonnebait-Mutis basin. The location of the vents has not been determined. The stratigraphical position and the character of the Mutis overthrust unit in Timor may give an indication that the volcanoes were located in the north of the Kekneno basin.Geographically the volcanic centra belonged to the afore mentioned Permian land mass. This continent had a bay which faced to the west into the present Banda sea.
Anatomites brochiiformis Welter var. rotundata
Get PDFDARI FOSIL-FOSIL CHEPALOPODA JANG TELAH DIKUMPULKAN di Basleo. Timor, oleh salah satu espedisi geologi dari Fakultas Ilmu Pasti dan Ilmu Alam, Universitas Indonesia di Bandung, beberapa telah diselidiki, antara lain species Anatomites brochiiformis. Untuk spesies ini, dua varian dapat ditentukan : ialah Anatomites brochiiformis var.rotundata jang mempunjai mulut dengan tinggi lebih ketjil daripada lebar, dan Anatomites brochiiformis var. elongata jang mempunjai mulut dengan tinggi lebih besar daripada lebar.
Coriolis Concept : Useful or Not?
Get PDFGAJA CORIOLIS DI SINI DIURAIKAN SECARA KWALITATIP. Perhitungannja didasarkan pada sistem salib sumbu-sumbu jang tetap dan lagi atas sistem salib sumbu yang bergerak (gaja coriolis). Diterangkan bahwa tjara dengan memakai sumbu jang tetap ini, adalah lebih mudah daripada tjara dengan perhitungan coriolis jang matematis komplex. Effek coriolis adalah menarik sekali, karena ini dapat memberi kesan yang salah, umpamanja untuk seorang pengamat satelit dari bumi. Djalan yang ditempuh satelit sesungguhnja terletak dalam bidang datar, tetapi si pengamat tadi melihatnja sebagai djalan lengkung.
Compound Sums and their Applications in Finance
Get PDFCompound sums arise frequently in insurance (total claim size in a portfolio) and in accountancy (total error amount in audit populations). As the normal approximation for compound sums usually performs very badly, one may look for better methods for approximating the distribution of a compound sum, e.g. the bootstrap or empirical Edgeworth / saddlepoint approimations. We sketch some recent developments and indicate their relevance in finance. Second, we propos and investigate a simple estimator of the probability of ruin in the Poisson risk model, for the special case where the claim sizes are assumed to be exponentially distributed
Analisis Penggunaan Autotrafo Penggeser Fasa sebagai minimisator Harmonisa Arus di Sistem Distribusi Tenaga Listrik
Get PDFSari. Meningkatnya aplikasi beban nonlinier di sistem distribusi tenaga listrik telah menyebabkan arus sistem menjadi sangat terdistorsi dengan kandungan harmonisa arus yang sangat tinggi (THD). Persentase THD arus sistem yang tinggi dapat menyebabkan beberapa persoalan harmonisa yang serius. Tulisan ini mengusulkan metode baru untuk meminimisasi harmonisa arus di sistem distribusi tenaga listrik, yaitu dengan menggunakan autrafo penggeser fasa sebagai minimisator.Dalam kasus ini, autotrafo bertindak sebagai penggeser sudut fasa tegangan suplai beban. Akibat penggeseran sudut fasa ini, beberapa komponen arus harmonisa yang signifikan pada sisi sumber tegangan sistem dapat dieleminir, sehingga harmonisa arus yang terdapat di sistem menjadi sangat minim. Secara detail, mekanisme minimisasi harmonisa arus sistem dengan menffunakan autotrafo dijelaskan, dan diberikan beberapa konfigurasi autotrafo penggeser fasa yang dapat digunakan sebagai minimisator harmonisa arus sistem. Hasil eksperimen laboratorium diberikan untuk menunjukkan validitas metode yang diusulkan. Analysis of Phase Shifting Autotransformer as Current Harmonic Minimisator on Power Distribution SystemAbstract. The increasing use of nonlinear loads has made the currents in power distribution system highly distorted with high level harmonic currents content (TIID) and created serious harmonics problems. This paper proposed a new method to minimize current harmonics in power distribution system by using phase shifting autotransformer. The loads of system are devided into two parts which are supplied by autotransformer with 30° phase shifting. The effects of the phase shifting which causes harmonic currents are cencelled, and the resulting currents harmonic in power distribution system are minimized. Detailed mechanism of current harmonic minimization is presented. Several configurations of phase shifting autotransformer are discussed and compared. The influence of load operating conditions are discussed. Experimental results are shown to verify this proposed method
Artonol B and Sikloartobilosanton dari Artocarpus teysmanii MIQ
No full textDua senyawa masing-masing turunan santon lakton, yaitu artonol B (1) dan turunan furanodihidrobenzosanton, yakni Sikloartobilosanton (2), telah ditemukan pada tumbuhan Artocarpus teysmanii Miq. (Moraceae), suatu tumbuhan langka yang endemik untuk Indonesia dan dikenal dengan nama Tipulu. Struktur molekul kedua senyawa tersebut telah ditetapkan berdasarkan data fisika dan spektroskopi (MS, 1H dan 13C NMR). Artonol B (1) dan sikloartobilosanton (2) memperlihatkan toksisitas yang tinggi terhadap udang Artemia salina, dan senyawa 2 juga memperlihatkan aktivitas antimitotik yang rendah terhadap target cdc2 kinase dan cdc25 fosfatase. Artonol B and Cycloartobiloxanthone from Artocarpus teysmanii MIQTwo compounds, a xanthone lactone derivative, namely artonol B (1) and a furanodihydrobenzoxanthone derivative, namely cycloartobiloxanthone (2) had been isolated from Artocarpus teysmanii Miq. (Moraceae), locally known as Tipulu. The structures of both compounds were elucidated based on physical and spectroscopic data (MS, 1H and 13C NMR). Both artonol B (1) and cycloartobiloxanthone (2) showed strong toxicity against Artemia salina in the shrimp bioassay, and compound 2 also showed weak antimitotic activity against cdc2 kinase and cdc25 phosphatase as the targets. Bagian ke-8 dari seri Ilmu Kimia Tumbuhan Moraceae Indonesia, untuk bagian ke-6 lihat pustaka [10]