Landau Levels as a Limiting Case of a Model with the Morse-Like Magnetic Field

We consider the quantum mechanics of an electron trapped on an infinite band along the $x$-axis in the presence of the Morse-like perpendicular magnetic field $\vec{B}=-B_{0}e^{-\frac{2\pi}{a_{0}}x}\hat{k}$ with $B_{0}>0$ as a constant strength and $a_{0}$ as the width of the band. It is shown that the square integrable pure states realize representations of $su(1,1)$ algebra via the quantum number corresponding to the linear momentum in the $y$-direction. The energy of the states increases by decreasing the width $a_{0}$ while it is not changed by $B_{0}$. It is quadratic in terms of two quantum numbers, and the linear spectrum of the Landau levels is obtained as a limiting case of $a_{0}\rightarrow\infty$. All of the lowest states of the $su(1,1)$ representations minimize uncertainty relation and the minimizing of their second and third states is transformed to that of the Landau levels in the limit $a_{0}\rightarrow\infty$. The compact forms of the Barut-Girardello coherent states corresponding to $l$-representation of $su(1,1)$ algebra and their positive definite measures on the complex plane are also calculated

Analisis Sifat Fisik dan Mekanik Kayu Kelapa Sawit Hasil Kompregnasi Melamine Formaldehyde

During the past time the utilization of palm oil tree only limited to producing fruit to produce oil with all their derivatives, as well as the utilization of husk and midrib. Stem, as the biggest mass palm oil tree has not been used commercially due to its lack of quality. One effort in improving quality of palm oil wood is compregnation. Compregnation interpreted as an effort of putting the chemicals into wood structure using prresure. Chemicals that can penetrate into wood structure in this case is melamine formaldehyde resin. The result of research showed that compregnation palm oil wood by melamine formaldehyde increased the specific of gravity of wood from 0,32 before compregnation to 0,48, 0,58 and 0,65 for 50%, 75% and 100% concentrate. Moisture content decreased from 12,05% before compregnation to 10,67 at 100% concentrate. MOR increased from 64,58 kg/cm2 before compregnation to 131,54 kg/cm2, 188,94 kg/cm2 and 361,14 kg/cm2 each for 50%, 75% and 100% concentrate

Analisis Strategi Positioning Merek Berdasarkan Preferensi, Persepsi, dan Kepuasan Konsumen Produk Pertamina Lubricants

Potensi industri pelumas sebagai industri strategis kian bertumbuh dari tahun ketahun. Hal ini disebabkan oleh meningkatnya penggunaan pelumas pada pasar otomotif dan juga perindustrian. Pertumbuhan potensi ini menarik bagi para produsen lokal maupun Internasional. Penelitian ini bertujuan untuk menganalisis sejauh mana atribut pelumas dapat mempengaruhi evaluasi konsumen terhadap positioning merek dan kompetisi terhadap merek lain, menganalisis faktor-faktor yang mempengaruhi kepuasan konsumen terhadap produk Pertamina Lubricants dan juga merumuskan alternatif strategi positioning berdasarkan persepsi dan kepuasan pelanggan. Penelitian ini menggunakan desain riset konklusif dan merupakan riset deskriptif. Teknik sampling yang digunakan adalah convenience sampling. Penelitian ini menggunakan perceptual map dikembangkan dengan menggunakan analisis diskriminan berganda, untuk menggambarkan posisi relatif setiap merek dan menggambarkan atribut merek. Hasil dari penelitian ini menunjukkan bahwa secara keseluruhan produk Pertamina Lubricants dicirikan dengan 3 atribut yaitu kemudahan diperoleh, harga dan kepopuleran merek. Selanjutnya dengan menggunakan analisis regresi berganda diketahui keenam atribut memiliki pengaruh positif signifikan terhadap manfaat yang dirasakan konsumen, atribut yang memiliki pengaruh paling besar adalah harga dan kepopuleran merek. Hasil dari analisis regresi sederhana didapati manfaat yang dirasakan berpengaruh positif signifikan terhadap kepuasan

Eksperimentasi Model Pembelajaran Kooperatif Tipe Numbered Heads Together (Nht) Dan Think Pair Share (Tps) Dengan Pendekatan Saintifik Pada Pokok Bahasan Himpunan Ditinjau Dari Kecerdasan Emosional Kelas VII SMP Negeri Di Kabupaten Sukoharjo

The objective of this research was to know the effect of the learning models on the learning achievement in Mathematics viewed from the emotional quotient of the students. The learning models compared were the cooperative learning model of the NHT type with scientific approach, the Cooperative Learning Model of the TPS type with scientific approach, and the classical model with scientific approach. This research used the quasi experimental research. It's population was all of the students in Grade VII of State Junior Secondary Schools in Sukoharjo. The samples of the research were taken by using the stratified cluster random sampling technique and consisted of 262 students. They were grouped into three classes, namely: 92 students in Experimental Class 1, 85 students in Experimental Class 2, and 85 students in Control Class. The instruments to gather the data were test of achievement in Mathematics on the learning topic of Set, and emotional quotient questionnaire. The proposed hypotheses of the research were analyzed by using the two way analysis of variance with unbalanced cells. The results of the research were as follows. 1) The cooperative learning model of the NHT type with scientific approach results in a better learning achievement in Mathematics than the cooperative learning model of the TPS type with scientific approach, and the classical model with scientific approach, the cooperative learning model of the TPS type with scientific approach results in a better learning achievement in Mathematics than the classical model with scientific approach. 2) Emotional quotient gives students a different effect on mathematics achievement of students in the topic of Set. The students with the high emotional quotient have a better learning achievement in Mathematics than those with the moderate emotional quotient and those with the low emotional quotient, the students with the moderate emotional quotient have a better learning achievement in Mathematics than those with the low emotional quotient. (3) There was not an interaction the aforementioned learning models and the categories of the emotional quotient on the learning achievement in Mathematics of the students

KARAKTERISTIK PERTUMBUHAN Tetraselmis sp. DAN Nannochloropsis sp.

Pemantauan pertumbuhan mikroalga (Tetraselmis sp. dan Nannochloropsis sp.) merupakan salah satu faktor penting dalam budidaya ikan dan udang. Tujuan penelitian ini adalah untuk mengetahui karakteristik pertumbuhan Tetraselmis sp. dan Nannochloropsis sp. dengan mengukur kerapatan optik menggunakan metode spektrofotometri. Penyerapan 600 nm digunakan untuk kedua spesies. Hasil penelitian menunjukkan bahwa pertumbuhan maksimum dicapai pada hari ke 6 untuk kedua mikroalga dengan nilai OD masing-masing 1,734 ± 0,013 dan 1,329 ± 0,002 untuk Tetraselmis sp. dan Nannochloropsis sp.. Tetraselmis sp. memiliki tingkat pertumbuhan maksimum 0,74/hari dan waktu penggandaan 22,43 jam sedangkan Nannochloropsis sp. memiliki tingkat pertumbuhan maksimum 0,86/hari dan waktu penggandaan 19,25 jam. Penelitian ini menunjukkan bahwa absorbansi 600 nm cocok untuk mengetahui pertumbuhan mikroalga hijau dan metode spektrofotometri yang dapat digunakan secara efisien untuk memantau pertumbuhan mikroalga

Komunitas Fitoplankton Pada Sistem Budidaya Intensif Udang Vaname, Litopenaeus Vannamei Di Probolinggo, Jawa Timur [Phytoplankton Community at Intensive Cultivation System of White Shrimp, Litopenaeus Vannamei in Pr

Fitoplankton merupakan sumber pakan alami pada budidaya udang di tambak. Produktivitas fitoplankton dapat meningkat seiring dengan bertambahnya kandungan nutrien di tambak. Sisa metabolisme dan pakan merupakan sumber nutrien bagi pertumbuhan fitoplankton di tambak. Penelitian ini bertujuan untuk mengevaluasi produktivitas dan mengidentifikasi jenis fitoplankton pada sistem budidaya intensif udang vaname, Litopenaeus vannamei. Penelitian ini dilakukan pada tiga petak tambak budidaya intensif udang vaname di Probolinggo, Jawa Timur. Pengambilan sampel air tambak dilakukan pada hari ke-17 dan hari ke-87 masa budidaya masing-masing dua kali setiap petak. Empat parameter lingkungan yaitu total ammonia nitrogen (TAN), nitrat, orthophosphate, total padatan tersupensi (TSS), dan klorofil diukur pada setiap sampel air tambak. Selain itu, kami juga mengidentifikasi dan menghitung fitoplankton pada setiap sampel. Hasil penelitian ini menunjukkan bahwa produktivitas pada ke tiga tambak berkisar antara 22.893,83 kg/ha sampai 23.600,61 kg/ha dengan ukuran panen 12,74 g/ekor sampai 14,35 g/ekor. Selama masa budidaya, konsentrasi TAN, TSS, dan klorofil meningkat seiring dengan semakin lamanya masa budidaya. Sementara itu, rerata kandungan nitrat dan orthophosphate cenderung menurun seiring bertambahnya masa budidaya. Jenis fitoplankton yang teridentifikasi yaitu dalam genus Oocystis, Chlorella, Nannochloropsis, Chaetoceros, Stephanodiscus, Nitzschia, Coscinodiscus, Cyclotella, dan Ulothrix. Fitoplankton dari kelompok Chlorophyta merupakan jenis yang dominan pada tambak 1 dan 2, sedangkan tambak 3 didominasi oleh kelompok Diatom. Penelitian ini mengindikasikan bahwa keberadaan fitoplankton di tambak mendukung ketersediaan pakan alami dan lingkungan yang baik bagi budidaya udang

AUTOMATIC FISHPOND IRRIGATION DOOR CONTROL SYSTEM BASED ON ATMEGA16 MICROCONTROLLER AND SMS GATEWAY

The process of controlling irrigation doors in fishponds is still mostly done manually, this results in the performance of farmers being less effective and efficient. Current technological developments, especially in the field of IoT, can be used to design a simulation that is able to control irrigation gates automatically. Based on the results of the tests that have been carried out, it can be concluded that the ATmega16-based automatic irrigation gate simulation tool can work well according to the designed working principle. If the condition of fishpond water is less than the ideal height of the fishpond and the condition of river water is more than the height of the fishpond, the motor will move to "open" the irrigation door to fill fishpond water. If the fishpond water condition is more than the ideal height and the river water condition is less than the fishpond height, the motor will move to "open" the irrigation door to discharge fishpond water and if the river water condition is the same as the fishpond water condition, the motor will move "close” the irrigation door so that the ideal height of the fishpond can be achieved. There are certain conditions to control the door manually using the SMS Gateway. Information about the maximum or minimum fishpond water level will be displayed on the LCD to determine the maximum or minimum fishpond height using Keypad