scholarly journals Graph of atomic orbitals and the molecular structure-descriptors based on it

2005 ◽  
Vol 70 (4) ◽  
pp. 669-674 ◽  
Author(s):  
Andrey Toropov ◽  
Ivan Gutman ◽  
Boris Furtula

The graph of atomic orbitals (GAO) is a novel type of molecular graph recently proposed by one of the authors. Various molecular structure-descriptors computed for GAO are compared with their analogs computed for ordinary molecular graphs. The quality of these structure-descriptors was tested for correlation with the normal boiling points of alkanes and cycloalkanes. In all the studied cases, the results based on GAO are similar to, and usually slightly better than, those obtained by means of ordinary molecular graps.

2013 ◽  
Vol 78 (6) ◽  
pp. 805-810 ◽  
Author(s):  
Ivan Gutman ◽  
Jelena Tosovic

The correlation ability of 20 vertex-degree-based topological indices, occurring in the chemical literature, is tested for the case of standard heats of formation and normal boiling points of octane isomers. It is found that the correlation ability of many of these indices is either rather weak or nil. The augmented Zagreb index and the atom-bond connectivity index yield the best results.


2015 ◽  
Vol 80 (8) ◽  
pp. 1009-1017 ◽  
Author(s):  
Ivan Gutman ◽  
Boris Furtula ◽  
Xueliang Li

The Wiener index W can be viewed as a molecular structure descriptor composed of increments representing interactions between pairs of atoms. A generalization of the W are the Steiner-Wiener indices kW, k=3,4,.... In the quantity Wk, interactions between k-tuples of atoms play role, based on the concept of Steiner distance. It is shown that the term W+?Wk provides an approximation for the boiling points of alkanes better than W itself. The best such approximation is obtained for k=7.


Mathematics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 271 ◽  
Author(s):  
Wei Gao ◽  
Muhammad Aamir ◽  
Zahid Iqbal ◽  
Muhammad Ishaq ◽  
Adnan Aslam

A graph is said to be a regular graph if all its vertices have the same degree, otherwise, it is irregular. Irregularity indices are usually used for quantitative characterization of the topological structure of non-regular graphs. In numerous applications and problems in material engineering and chemistry, it is useful to be aware that how irregular a molecular structure is? Furthermore, evaluations of the irregularity of underline molecular graphs could be valuable for QSAR/QSPR studies, and for the expressive determines of chemical and physical properties, such as enthalpy of vaporization, toxicity, resistance, Entropy, melting and boiling points. In this paper, we think over the following four irregularity measures: the irregularity index by Albertson, σ irregularity index, the total irregularity index and the variance of vertex degrees. By way of graph structural estimation and derivations, we determine these irregularity measures of the molecular graphs of different classes of dendrimers.


2007 ◽  
Vol 62 (9) ◽  
pp. 495-498 ◽  
Author(s):  
Ivan Gutman ◽  
Boris Furtula ◽  
Violeta Marković ◽  
Biljana Glišić

If λ1 >λ2 ≥λ3 ≥ · · · ≥λn are the eigenvalues of the molecular graph, then the Estrada index, a recently conceived molecular structure-descriptor is EE = nΣ i=1eλi . The same alkanes, whose molecular graphs have extremal Wiener indices and λ1, are shown to be also extremal with regard to the Estrada index.


2012 ◽  
Vol 67 (6-7) ◽  
pp. 403-406 ◽  
Author(s):  
Ivan Gutman

Lower and upper bounds for the Laplacian energy-like (LEL) molecular structure descriptor are obtained, better than those previously known. These bonds are in terms of number of vertices and edges of the underlying molecular graph and of graph complexity (number of spanning trees)


Liquidity ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 151-159
Author(s):  
Pitri Yandri

The purpose of this study is (1) to analyze public perception on urban services before and after the expansion of the region, (2) analyze the level of people's satisfaction with urban services, and (3) analyze the determinants of the variables that determine what level of people's satisfaction urban services. This study concluded that first, after the expansion, the quality of urban services in South Tangerang City is better than before. Secondly, however, public satisfaction with the services only reached 48.53% (poor scale). Third, by using a Cartesian Diagram, the second priority that must be addressed are: (1) clarity of service personnel, (2) the discipline of service personnel, (3) responsibility for care workers; (4) the speed of service, (5) the ability of officers services, (6) obtain justice services, and (7) the courtesy and hospitality workers.


2019 ◽  
Vol 9 (01) ◽  
pp. 47-54
Author(s):  
Rabbai San Arif ◽  
Yuli Fitrisia ◽  
Agus Urip Ari Wibowo

Voice over Internet Protocol (VoIP) is a telecommunications technology that is able to pass the communication service in Internet Protocol networks so as to allow communicating between users in an IP network. However VoIP technology still has weakness in the Quality of Service (QoS). VOPI weaknesses is affected by the selection of the physical servers used. In this research, VoIP is configured on Linux operating system with Asterisk as VoIP application server and integrated on a Raspberry Pi by using wired and wireless network as the transmission medium. Because of depletion of IPv4 capacity that can be used on the network, it needs to be applied to VoIP system using the IPv6 network protocol with supports devices. The test results by using a wired transmission medium that has obtained are the average delay is 117.851 ms, jitter is 5.796 ms, packet loss is 0.38%, throughput is 962.861 kbps, 8.33% of CPU usage and 59.33% of memory usage. The analysis shows that the wired transmission media is better than the wireless transmission media and wireless-wired.


2018 ◽  
Vol 5 (2) ◽  
pp. 102
Author(s):  
Enike Dwi Kusumawati ◽  
Selvinus Lawu Woli ◽  
Aju Tjatur Nugroho Krisnaningsih ◽  
Waluyo Edi Susanto ◽  
Syam Rahadi

ABSTRAKPenelitian ini dilakukan untuk mengetahui motilitas dan viabilitas spermatozoa ayam kampung pada suhu 5oC menggunakan pengencer dan lama simpan yang berbeda. Metode yang digunakan dalam penelitian ini adalah penelitian laboratorium menggunakan Rancangan Acak Lengkap (RAL) Faktorial dengan pengencer ringer lactat solution, air kelapa dan tanpa pengencer serta lama simpan 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, masing-masing diulang 10 kali. Variabel yang diamati yaitu motilitas dan viabilitas spermatozoa. Analisa data yang digunakan adalah analisis varian. Hasil analisis data menunjukkan bahwa motilitas dan viabilitas spermatozoa menggunakan pengencer ringer lactat solution lebih tinggi (P<0,01) serta dapat bertahan sampai lama simpan 24 jam dibandingkan air kelapa dan tanpa pengencer. Adapun nilai motilitas ringer lactat solution, air kelapa dan tanpa pengencer pada lama simpan 24 jam masing-masing sebesar 43,5±17,17%; 8±4,83%; 6,5±2,4%, sedangkan nilai viabilitasnya sebesar 83,2±7,25%; 64,6±3,20%; dan 63,1±2,33%. Kesimpulan dari hasil penelitian ini adalah ringer lactat solution lebih baik dibandingkan air kelapa dan tanpa pengencer dalam mempertahankan kualitas semen ayam kampung pada suhu simpan 5oC sampai lama simpan 24 jam.Kata Kunci : air kelapa, ayam kampung, motilitas, spermatozoa, viabilitas  ABSTRACTThis study was conducted to determine the motility and viability of spermatozoa of Native chickens at 5oC using different diluents and time storage. The method used in this study was laboratory research using Factorial Completely Randomized Design with ringer lactate solution, coconut water and without diluent at 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 hours of time storage each repeated 10 times. The variables observed were motility and viability of sperm. Data analysis used is variance analysis. The results of data analysis showed that the motility and viability of spermatozoa using ringer lactate solution diluents was higher (P <0.05) than coconut water and without diluents. The motility values of ringer lactat solution, coconut water and without diluents were 43,5±17,17%; 8±4,83%; 6,5±2,4% respectively, while the viability values were 83,2±7,25%; 64,6±3,20% and 63,1±2,33%. The conclusion of this study is that ringer lactat solution is better than coconut water an without diluents in maintaining the quality of Native chicken semen at a storage temperature of 5oC until 24 hours.Keywords: coconut water, motility, native chicken, sperm, viability


2017 ◽  
Vol 2 (3) ◽  
pp. 288
Author(s):  
Dimas Satriadi

<p><em>The quality of public service is an important and it must have bye the each public service institution. Includes the library as a public service institution giving service for the all visitors. This research aims to know the comparisation of Kepri Province Libraries quality service  and Tanjungpinang City Libraries quality service. The method used in this research is quantitative methods with questionnaire to 40 responden as samples. This questionnaire as an data collecting instruments. These results indicate the quality of two libraries is good. But, if they compared the service quality of  Province Kepri  Libraries is better than  Tanjungpinang City Libraries. This look from average scored  results is 152,61 points  for Kepri Province Libraries, and 150,66 points for Tanjungpinang City Libraries, in the good categories</em></p><p>Kualitas pelayanan publik merupakan hal yang penting dan harus dimiliki oleh masing-masing lembaga pelayanan publik. Termasuk perpustakaan sebagai lembaga pelayanan publik yang memberikan pelayanan kepada semua pengunjung. Penelitian ini bertujuan untuk mengetahui perbandingan kualitas layanan Perpustakaan Provinsi Kepri dan kualitas pelayanan Perpustakaan Kota Tanjungpinang. Metode yang digunakan dalam penelitian ini adalah metode kuantitatif dengan 40 responden sebagai sampel. Kuesioner ini sebagai alat pengumpul data. Hasil penelitian ini menunjukkan kualitas kedua perpustakaan suda bagus. Tapi jika dibandingkan kualitas pelayanan Perpustakaan Provinsi Kepri lebih baik dari pada Perpustakaan Kota Tanjungpinang. Hasil dari hasil rata-rata ini adalah 152,61 poin untuk Perpustakaan Kepri Province, dan 150,66 poin untuk Perpustakaan Kota Tanjungpinang, dalam kategori baik.</p><p><em><br /></em></p>


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 687
Author(s):  
Salman Sakib ◽  
Dawit Ghebreyesus ◽  
Hatim O. Sharif

Tropical Storm Imelda struck the southeast coastal regions of Texas from 17–19 September, 2019, and delivered precipitation above 500 mm over about 6000 km2. The performance of the three IMERG (Early-, Late-, and Final-run) GPM satellite-based precipitation products was evaluated against Stage-IV radar precipitation estimates. Basic and probabilistic statistical metrics, such as CC, RSME, RBIAS, POD, FAR, CSI, and PSS were employed to assess the performance of the IMERG products. The products captured the event adequately, with a fairly high POD value of 0.9. The best product (Early-run) showed an average correlation coefficient of 0.60. The algorithm used to produce the Final-run improved the quality of the data by removing systematic errors that occurred in the near-real-time products. Less than 5 mm RMSE error was experienced in over three-quarters (ranging from 73% to 76%) of the area by all three IMERG products in estimating the Tropical Storm Imelda. The Early-run product showed a much better RBIAS relatively to the Final-run product. The overall performance was poor, as areas with an acceptable range of RBIAS (i.e., between −10% and 10%) in all the three IMERG products were only 16% to 17% of the total area. Overall, the Early-run product was found to be better than Late- and Final-run.


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