137,681 research outputs found
Asymptotic inference for nearly unstable AR(p) processes
No full textIn this paper nearly unstable AR( p) processes (in other words, models with characteristic roots near the unit circle) are studied. Our main aim is to describe the asymptotic behavior of the least-squares estimators of the coefficients. A convergence result is presented for the general complex-valued case, The limit distribution is given by the help of some continuous time AR processes. We apply the results for real-valued nearly unstable AR(p) models. In this case the limit distribution can be identified with the maximum likelihood estimator of the coefficients of the corresponding continuous time AR processes
Tribological characterization of smooth diamond films grown in Ar-C-60 and Ar-CH4 plasmas
No full textIn this paper, we describe the fundamental tribological mechanisms of smooth, nanocrystalline diamond films grown in Ar-C-60 and Ar-CH4 plasmas. These films can provide very low friction coefficients (approximate to 0.04 to 0.15) to sliding SiC and Si3N4 surfaces in air or dry N-2. To understand the mechanisms of friction and wear behavior in relation to the chemical and physical states of the diamond films, we used a variety of analytical techniques (electron diffraction, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, atomic resolution transmission electron microscopy, near-edge X-ray absorption fine structure, and atomic force microscopy) both before and after sliding tests. The results of these studies verified that the films were made of sp(3)-bonded diamond nanocrystals (100-300 Angstrom) and that their surfaces were exceptionally smooth (i.e., 20-40 nm, root mean square). Additionally, pin-on-disk experiments verified that these films provided very low friction coefficients (0.04, in dry N-2) and wear rates, essentially comparable to those of natural diamond. Undoubtedly, such diamond films with smooth surface finish can have significant impact in a wide range of tribological applications
The Crystal Structure of Selenourea at 20°C and ar -100°C
No full textTitle: The Crystal Structure of Selenourea at 20°C and ar -100°C, Author: John S. Rutherford, Location: ThodeThe trigonal form of selenourea has been
examined by X-ray crystallographic methods both at room temperature
and at a lower temperature ( -100°C) . The lattice parameters of
earlier workers have been refined and the space group assignment,
which requires nine crystallographically distinct SeC(NH2)2
molecules, confirmed. The crystal structure was solved using a
novel Patterson technique and differences Fourier syntheses, and
was refined by least squares using three - dimensional data obtained
0 at -100°C. Both the molecular dimensions and the crystal structure
found are compared to other members of the urea series, and the
similarity of the crystal structure to the urea- and thioureahydrocarbon
complexes discussed. Evidence is presented of N-H...Se
hydrogen bonds, supporting their recent discovery in chemically
related compounds.ThesisDoctor of Philosophy (PhD
Rayleigh number dependence of the Archimedes number dependent large-scale flow structure formation in mixed convection
No full textWe report on experimental investigations of large-scale flow structure formation in mixed convection. We characterize the flow field by measuring the velocity fields within a rectangular model room using 2D2C PIV. The control parameters are the Reynolds number Re, the Rayleigh number Ra and the Prandtl number Pr. All parameters are linked through the Archimedes number Ar. In 6.4x10-2 ≤ Ar ≤ 1.39x101, 4.2x103 ≤ Re ≤ 6.35x104 and Ra = 3.1x107, Ra = 1.8x108 and Pr = 0.713 we found flow 3 different flow structures. While keeping Ra and Pr constant and varying Ar through Re variations, we found an Ar dependence of the largescale flow structure formation within 6.4x10-2 ≤ Ar ≤ 1.39x101. Furthermore, we found a Ra dependence of the structure formation, which shifts the transition points between the structures to higher Archimedes numbers and reduces the mean velocities within the investigated domain
Ittijahat Abi Dhu'ayb Al-Hudhali fi Qasidatihi Ar-Ritsa’
No full textThis article aims to know Ittijahat of Abu Dhu’ayb Al-Hudhali in his poem of Ritsa’. Ittijahat in this study is a description of the poet's tendency to divide Ar-Ritsa', namely Nadb and Ta'ziyah. Ar-Ritsa 'is one of the various forms of Arabic poetry. To analyze the discussion problem, the author uses descriptive analysis method, because this method is very appropriate to find out the picture and state of a thing by describing it in as much detail as possible based on the facts found in the data in question. The results obtained are: In the beginning of the poem, he tends to mourn (Nadb) their five children. He describes in it that he does not stop crying and has trouble sleeping until he becomes weak emaciated due to the intensity of the grief, pain and worries that dominated in his pysche. As for the middle of the poem to the end, the poet turns to the consolation (Ta’ziyah) of his children’s death, as he reflects on the reality of life and death, the poet declares that death is inevitable for every human being that he must accept it and let it go, which the poet portrayed in the exciting narrative style. The story is divided into three stories: the zebra, the bull of the beast, and the two knights.</jats:p
Giresun ilinde ar c l n genel yap s ve ar c l k faaliyetleri
No full textBu tez çal mas nda, Giresun ilinde ar c l k faaliyeti sürdürenlerin çal ma prensipleri ve temel sorunlar ele al nmaktad r. Ar c l kta uygulanan yöntemler ve ar c l k uygulamalar nda kar la lan sorunlar hakk nda bilgi vermekte ve bu durumlar Giresun ili baz nda de erlendirmektedir. Giresun ilinin klimatik ve topo rafik özellikleri dikkate al narak bu faktörlerin ar c l k üzerindeki etkisi de incelenmi tir. Giresun ilinde ar yeti tiricilerinin sosyo-ekonomik ve sosyo-kültürel özellikleri, ar yeti tiricili i, besleme, üretim, hasat durumlar , ar yeti tiricilerine sunulan destek, örgütlenme ve denetim hizmetleri, ar hastal klar , ar lar k latma, koloni kay plar , ürünlerin pazarlama ve ticaretinde kar la lan durumlar hakk nda bilgiler elde edilmek için bu çal ma gerçekle tirilmi tir. Ar c l k faaliyetlerini etkileyen faktörleri tespit etmek için Giresun il merkezi ve merkeze ba l 15 ilçesinde Giresun Ar c lar Birli ine kay tl olan, 150 ar i letmecisine yüz yüze anket uygulanm ve istatistiksel verilere ula lm t r. Ar c l k birliklerine ve i letmelerine ba l olarak çal an ve ar c l k faaliyeti ile u ra an insanlarla do rudan saha içinde uygulanan yüz yüze anket formalar n n sonuçlar , ara t rman n veri kaynaklar n olu turmaktad r
AR-13-24
No full textCollection ID: AR-13-24 | Taxon: Centaurea solstitialis L. | Common name: Yellow starthistle | Collection locality: Santa Rosa, Argentina (latitude -37.39, longitude -64.08) | Plant tissues employed for EST library development: Leaves | Library type: Normalized, double-stranded | Sequence type: 45
Program “I’dad Lughowi” dalam Upaya Membekali Kemampuan Bahasa Arab Mahasiswa STIBA Ar-Raayah, Sukabumi
No full textNowdays, Arabic already has its own charm. Apart from the Al-Quran and Hadith as sources of Islamic Shari'a which are imported from the original source in Arabic, the emergence of scientific disciplines linked to Shari'a adds to the public's attraction and interest in studying Shari'a directly from its Arabic sources. Arabic language learning is starting to emerge with various strategies and methods applied. Some are successful and others need review. In this article, the author wants to examine Arabic language learning in the STIBA Ar-Raayah i'dad lughowi program which is considered successful because it has produced many regional, national and even international achievements. This article aims to examine the background of students in the STIBA Ar-Raayah i'dad lughowi program, the teaching and learning activities of the i'dad lughowi program at STIBA Ar-Raayah and the examination system implemented in the i'dad lughowi program. This article is a case study at STIBA Ar-Raayah using a descriptive qualitative approach. The results found in this research are (1) the background of students in the STIBA Ar-Raayah i'dad lughowi program who come from various regions and schools, (2) learning using the Arabiyyah book Baina Yadaik by maximizing the direct method and activities outside the classroom, (4) a unique exam system with Al-Qur'an exams, subject exams, syahri exams, nihai exams, as well as a rosib system for students who do not reach the minimum completion criteria. The results and conclusions of this research can be used as a reference for Arabic language educational institutions to make them more effective in the future
- …
