The main function of a fluid-conveying pipe is to transport the fluid. However, sometimes, it must be attached by some concentrated lumped masses such as the bushings, fire plugs, pumps or valves, etc. In addition, for safety, it may be supported by the translational springs or rotational springs. Since the natural frequencies and mode shapes of a structure can be changed to reduce the serious vibrations by adjusting the stiffnesses and masses of the attached spring-mass (S-M) systems, thus, the concentrated elements (CEs) attached to a beam or a pipe may also include the S-M systems. Because the CEs significantly affect the dynamic characteristics of the attached beams, the literature concerned is plenty. However, the information regarding a fluid-conveying pipe carrying various CEs is rare. The key point of this paper is to study the influence of various CEs on the dynamic stability and free vibration characteristics of the fluid-conveying Timoshenko pipes with the analytical-and-numerical combined method (ANCM). To the last end, the natural frequencies and mode shapes of the “bare” pipe (without attachments) are determined first, and then the matrix equation of motion for the “loaded” pipes (carrying various CEs) is derived by using the mode superposition method (MSM). Use of the computer programs available for the solution of the complex roots, one can obtain the critical flow velocity, and damped natural frequencies and mode shapes of the “loaded” pipes from the last matrix equation of motion. Finally, the same numerical examples are repeated by using the finite element method (FEM), and it is found that the results of the above-mentioned two approaches are in good agreements. This confirms the reliability of the presented theory and the developed computer programs for this paper..
In this study we were interested in assessing the impact of different NPK regimes and their effects on wheat Triticum durum. The preliminary results show that the presence of the fertilizer causes a decrease in the percentage and speed of germination and inhibition of the growth of wheat. In our work, we have demonstrated an inhibition of the respiratory activity of roots in the presence of different regimes of NPK. And inhibition of respiration and photosynthesis of plants of wheat seeds in the presence of NPK.
This research is focused on the ugly side of politicians and political parties in Nigeria. Four political parties were used to infer information on what the voting populace considers when casting their vote. The contingency table, the Chi squared, the likelihood ratio Chi squared and the Cramer’s V were used. The analysis revealed the rejection of the null hypothesis indicating the acceptance of the alternate hypothesis. This result indicated that the voting age in Nigeria will willingly cast their vote to aspirants and political parties whose ideology is based on development and internal democracy. This implies outright rejection of political parties whose ideology is based on regional and religious sentiment. The Cramer’s V suggested that there is strong association between the profiles and the political parties. In other words, the profiles of the political party are direct manifestation of the aspirant’s ideology.
Knowledge discovery process from databases has gained importance recently. Finding and using the valuable and meaningful data which is hidden in large databases can have strategic importance for the organizations to gain competitive advantage. Knowledge discovery process that is based on data mining consists of two methods named symbolic and numerical. Association rules based on lattice reflect the relationships among the attributes in a database. The symbolic methods based on formal concept analysis classification are frequent itemset search and association rule extraction. \nConcept lattices are the knowledge representation of Formal Concept Analysis which has been originally developed as a subfield of Applied Mathematics.\nIn this study, the mathematical background and definition of formal concept analysis which is a powerful tool in knowledge representation and discovery are explained. Also, Association Rule Mining based-on Formal Concept Analysis is explained. Then, an experimental study is given in personnel selection function of human resources management by using formal concept analysis method to model the qualifications of candidates during the recruitment process by taking into consideration the essential qualifications needed for the job position. The qualifications of the candidates are modeled with concept lattices. After that association rules and implications are obtained in order to facilitate the decision making process to select the appropriate candidate for the vacant position.
Objectives: Melasma is an acquired hyperpigmentation on the face, which generally happens in women between the ages of 30 to 35. If treatment is not performed in a timely manner, many cosmetic problems can arise. The aim of this study was to compare the effects of kojic acid and hydroquinone 2% creams for the treatment of melasma. Methods: 100 women with epidermic melasma who were referred to the dermatology department of the 22 Bahman Hospital in Mashhad were used in this clinical trial. Each patient had at least two melasma lesions of similar severity and size on both sides of the face. For each patient, kojic acid cream on one side of the face and hydroquinone 2% cream on the other side of the face were prescribed. The researchers assessed the rate of improvement over a three month period. Results: For both applications, a positive response of 7% for kojic acid treatment and 10% for hydroquinone treatment were seen one month after beginning the treatment. After two months, a positive response of 24% for kojic acid and 22% for hydroquinone was observed. The differences were not statistically significant between two groups after 2 months, but statistical significance was seen after 3 months, with positive responses of 58% for kojic acid and 30% for hydroquinone. Conclusion: Kojic acid was more suitable than hydroquinone for the treatment of melasma. Therefore, kojic acid should be considered in the protocol of treatment for this pigmentation disorder.
The novel Schiff bases: N,N\'-bis(3,4-dimethoxybenzylidene)ethane-1,2-diamine (1), N,N\'-bis[4-(diethylamino)benzylidene]ethane-1,2-diamine (2), N,N\'-bis[(5-methylfuran-2-yl)methylene]ethane-1,2-diamine (3) and N,N\'-bis(2-methoxybenzylidene)ethane-1,2-diamine (4), having nucleus of ethylenediamine, were synthesized by the condensation of carbonyl compound and ethylenediamine in absolute ethanol along with conc. H2SO4. The synthesized Schiff bases were characterized by 1H-NMR, IR, FAB-MS and elemental analyses. These Schiff bases (1-4) were checked for antioxidant, lipoxygenase, urease and chymotrypsin inhibition activities and Schiff base (4) was found to be significant (IC50 26.9) in urease inhibition assay.
We examined the influence of burnout on life satisfaction level of employees. Data were obtained from 350 employees in different industry sectors. In order to determine the impact of burnout on life satisfaction level, regression analysis was carried. According to the results, emotional exhaustion and personal accomplishment were found as the factors that explain life satisfaction. Recommendations are presented to researchers and suggestions for future research are discussed.
Cyber terrorism is a crime that is viewed as threat that is extremely dangerous. From the legal aspect, the new methods of deploying cyber terrorism attacks and the threats posed by cyber terrorism still remain unclear. Countries must recognize such threats from ancillary cyber activities, in order to provide proper respond against them. The two identical notions of cyber terrorism and ancillary cyber activities should not be confused. Cyber terrorism and terrorist use of the Internet are different issues that are often confused as being the same. Differentiating between these two notions is not easy although in combatting this menace it is important to have a precise definition of the two activities. This paper addresses the issue of distinction between cyber terrorism activities and cyber ancillary activities
The maturity of the financial markets and the stronger interdependencies between their segments are registered also in the field of supervising market players, the actual trend is to switch from a proactive approach – based on norms and regulations, to a reactive one – where the emphasis is placed on self-regulating and internal risk management. \nThe development of the private health insurance, by issuing the new legal provisions in this field, has reopened the subject of the risks for this type of products.\nTaking into account the above mentioned, the work is aiming an inventory of the main risk categories from the private health insurance field, as well as the global and individual management models for the identified risks.
Plasma cell leukemia (PCL) is a rare and aggressive cancer involving plasma cells. There are two forms of PCL (with or without multiple myeloma). Although patients with primary and secondary PCL share several clinical features, important differences exist. We report on a case diagnosed with primary PCL. We analyzed the clinicopathologic and laboratory features of the disease.