Pub Date : 2022-12-01DOI: 10.36120/2587-3644.v14i2.106-116
Iurie Baltag
In this paper, various exact solutions of the stationary Navier-Stokes equations, which describe the planar flow of an incompressible liquid (or gas), are determined, i.e., solutions containing the components of the velocity of flow - the functions u, v and the created pressure P. We mention that in the paper a series of exact solutions is obtained, in which the viscosity coefficient lambda participates explicitly.
{"title":"On determination on some exact solutions of the stationary Navier-Stokes equations","authors":"Iurie Baltag","doi":"10.36120/2587-3644.v14i2.106-116","DOIUrl":"https://doi.org/10.36120/2587-3644.v14i2.106-116","url":null,"abstract":"In this paper, various exact solutions of the stationary Navier-Stokes equations, which describe the planar flow of an incompressible liquid (or gas), are determined, i.e., solutions containing the components of the velocity of flow - the functions u, v and the created pressure P. We mention that in the paper a series of exact solutions is obtained, in which the viscosity coefficient lambda participates explicitly.","PeriodicalId":398181,"journal":{"name":"Acta et commentationes Ştiinţe Exacte şi ale Naturii","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114604869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.36120/2587-3644.v14i2.117-131
Liubomir Chiriac, Aurel Danilov, V. Bogdanova
This paper studies encryption and decryption algorithm, using isotopes of Latin groupoid. Cryptographic algorithms are computationally intensive processes which consume large amount of CPU time and space during the process of encryption and decryption. The goal of this paper is to study the encryption and decryption algorithm with the help of the concept of Latin groupoid and notion of isotopes. The proposed algorithm is safe in the implementation process and can be verified without much difficulty. An example of encryption and decryption based on the atin groupoid and the concept of isotopy is examined.
{"title":"Encryption and decryption algorithm based on the Latin groupoid isotopes","authors":"Liubomir Chiriac, Aurel Danilov, V. Bogdanova","doi":"10.36120/2587-3644.v14i2.117-131","DOIUrl":"https://doi.org/10.36120/2587-3644.v14i2.117-131","url":null,"abstract":"This paper studies encryption and decryption algorithm, using isotopes of Latin groupoid. Cryptographic algorithms are computationally intensive processes which consume large amount of CPU time and space during the process of encryption and decryption. The goal of this paper is to study the encryption and decryption algorithm with the help of the concept of Latin groupoid and notion of isotopes. The proposed algorithm is safe in the implementation process and can be verified without much difficulty. An example of encryption and decryption based on the atin groupoid and the concept of isotopy is examined.","PeriodicalId":398181,"journal":{"name":"Acta et commentationes Ştiinţe Exacte şi ale Naturii","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114843891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.36120/2587-3644.v14i2.88-100
D. Cozma
In this paper for a cubic differential system with a singular pointO(0,0) of acenter or a focus type, having two homogeneous invariant straight lines and exponentialfactors, we determine conditions under which the singular point is a center.
{"title":"Center conditions for a cubic system with two homogeneous in variant straight lines and exponential factors","authors":"D. Cozma","doi":"10.36120/2587-3644.v14i2.88-100","DOIUrl":"https://doi.org/10.36120/2587-3644.v14i2.88-100","url":null,"abstract":"In this paper for a cubic differential system with a singular pointO(0,0) of acenter or a focus type, having two homogeneous invariant straight lines and exponentialfactors, we determine conditions under which the singular point is a center.","PeriodicalId":398181,"journal":{"name":"Acta et commentationes Ştiinţe Exacte şi ale Naturii","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126442109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.36120/2587-3644.v14i2.101-105
S. Corlat, Veaceslav Guzun, Victor Vorona
The problem we are trying to solve sounds as follows: You are given N bits.Find the value of each bit. We will show a technique which enables finding the values of N bits using O(N/logN) subsequence-sum queries. The algorithm consists of two phases: Constructing the queries for each layer and using the queries for a particular layer to getthe value of every bit. We described the following technique in this blog [1], which wasinspired by this article [2]. It should be noted that this number of queries is indeed theoptimal one for finding all N bits of a binary array, since each subsequence-sum queriesoffers us at most log(2)N bits of information.
{"title":"Finding N bits using O(N/logN) sums","authors":"S. Corlat, Veaceslav Guzun, Victor Vorona","doi":"10.36120/2587-3644.v14i2.101-105","DOIUrl":"https://doi.org/10.36120/2587-3644.v14i2.101-105","url":null,"abstract":"The problem we are trying to solve sounds as follows: You are given N bits.Find the value of each bit. We will show a technique which enables finding the values of N bits using O(N/logN) subsequence-sum queries. The algorithm consists of two phases: Constructing the queries for each layer and using the queries for a particular layer to getthe value of every bit. We described the following technique in this blog [1], which wasinspired by this article [2]. It should be noted that this number of queries is indeed theoptimal one for finding all N bits of a binary array, since each subsequence-sum queriesoffers us at most log(2)N bits of information.","PeriodicalId":398181,"journal":{"name":"Acta et commentationes Ştiinţe Exacte şi ale Naturii","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129469930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.36120/2587-3644.v14i2.132-134
Nicolai Aluchi
The monograph "Study of useful properties of some coordination compounds containing oximic ligands", ISBN 978-3-9402237-24-8, presents a study in the field of synthesis, determination of the composition and structure of new coordination compounds based on ligands with various functional groups, as well as the determination of the fields of practical utility of the new substances. The work includes four chapters on 266 pages.
{"title":"Book Review: Study Of Useful Properties Of Some Coordination Compounds Containing Oximic Ligands, by E. Coropceanu, A. Ciloci, A. Ștefîrță, I. Bulhac, ISBN 978-3-9402237-24-8, 266 p.","authors":"Nicolai Aluchi","doi":"10.36120/2587-3644.v14i2.132-134","DOIUrl":"https://doi.org/10.36120/2587-3644.v14i2.132-134","url":null,"abstract":"The monograph \"Study of useful properties of some coordination compounds containing oximic ligands\", ISBN 978-3-9402237-24-8, presents a study in the field of synthesis, determination of the composition and structure of new coordination compounds based on ligands with various functional groups, as well as the determination of the fields of practical utility of the new substances. The work includes four chapters on 266 pages.","PeriodicalId":398181,"journal":{"name":"Acta et commentationes Ştiinţe Exacte şi ale Naturii","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124716874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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