This paper presents the free vibration analysis of stiffened isotropic plate by means of finite element method. Stiffeners are used in plates to increase the strength and stiffness. The effect of position of stiffeners on isotropic plate has been studied which involve the possible combination of clamped and free edge condition. The model has been discretized using a 20-node solid element (SOLID186) from the ANSYS element library. The natural frequencies are calculated using Block-Lanczos algorithm. The comparisons of stiffened plate with the available results are found to be in good uniformity. The effect of different boundary conditions, stiffeners location, thickness ratio, stiffener thickness to plate thickness and aspect ratio on the vibration analysis of stiffened plates has been studied.

New silica-supported yttrium trinitrate was prepared, characterized, and used as a reusable catalyst for the three-component synthesis of quinazolinones/thiones via the Biginelli condensation under solvent-free conditions. Non-toxic reagent, short reaction times, simple work-up procedure, and high yield of the products are some of the important advantages of present method.

The positive effect of globalization has continued to impact FDI inflow to developing countries during the last decade except for the rising influence of political risk in host locations. Mixed outcomes have trailed the findings related to the studies on FDI and political risk relationship and in particular on African countries like Nigeria. This paper investigated the effect of political risk on FDI inflow to Nigeria using secondary data from 2000 to 2014 using simple linear regression. The study combined from select variables, the institutional factors with location determinants peculiar to Nigeria’s risk environment. It is found that political risk holds a positive and significant association with FDI to Nigeria but not close enough to inhibit the inflow of foreign investment to the country. However, the findings provide a strong basis for policy shift in relation to security, country promotion and rebranding as well strengthening of institutions.

Evaluating the capability of electrospinning method as an efficient versatile approach for fabrication of fibers, a central composite design (CCD) model was used to design an experimental program for investigation of effective in production of poly (vinyl alcohol) (PVA) fibers fabricated from aqueous solutions of PVA. The studied variables were polymer solution concentration, applied voltage, distance between nozzle and collector plate and flow rate of solution injection. The influence of these parameters on diameter and morphology of obtained PVA fibers was studied by SEM analysis. Among all factors, concentration would strongly affect the fiber diameter.

Head injuries are among the dangerous injuries which are common in all sport types. In the present study, the dynamic response of a punch to the head of a Wushu fighter was simulated by modeling the human head in ABAQUS software. Moreover, the maximum displacement and the stress distribution in the helmet and head parts were analyzed by finite elements method. The obtained results showed a significant interval in the response of different tissues to the delivered blow. The maximum shear stress, normal stress and displacement in the helmet were 5.616 MPa, 5.755 MPa and 1.236 mm, respectively, while these magnitudes were respectively 3.199 MPa, 6.268 MPa and 0.0001867 mm in skull, 4.596 MPa, 3.691 MPa and 0.1180 mm in the head skin and 0.01098 MPa, 0.8779 MPa and 0.04993 mm in brain. The present model with its unique features can be a valuable and powerful instrument to gain a better insight into the injury mechanism for better diagnosing of injuries and to design protective helmets with higher efficiency and safety for various sport forms as well.

The growing field of behavioral economics (BE) has revolutionized the way we look at economic behavior at micro and macro levels. Importance of foreign direct investment (FDI) appeals for analysis of decisions made regarding it to be assessed from expanding view of BE. This research provides overview of previous studies and focuses on the case of Bosnia and Herzegovina (B&H) as representative of emerging markets to investigate motivations for investing into this country by temporarily present foreign companies. Empirical analysis was based on the questionnaire that was disseminated among foreign investors to B&H. Questionnaire contained motivations for investing in B&H, where examined motivation factors were divided in two groups; namely irrational and rational ones. Choice of methodology was narrowed due to moderate sample size, but consisting of quality the sample members. In order to analyze data, descriptive statistics, correlation analysis and regression analysis were used. By regressing two groups of predictors on annual amount of foreign investments to B&H, it was shown that the highest motivation for investing was business instinct.

Optimal method were developed for the green synthesis of quinoxaline derivatives based on the highly efficient and simple condensation reaction of various aromatic 1,2-diketones and 1,2-diamines in nearly quantitative yields in water. In this method we did not use any catalyst. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route for synthesis of quinoxalines.

This paper presents a comprehensive scientometric study for the impact of social networks on advertisement. The study uses the Scopus database as a search engine to accomplish the survey. To better understand the evolution and identity of this category, the study covers 1216 most cited data over the period 1983-2019. Qualitative and quantitative data analysis techniques are applied to determine author distribution, country, individual and institutional-level productivity rankings. In terms of keywords, the study indicates that social media was jointly studied with gender and be-havior and researchers from the United States maintained the highest rate of contribution. The survey also indicates that there were strong collaboration between the researchers from China and United States. Moreover, there were also remarkable collaborations between the researchers in United States from one side and other countries.

An analytical and numerical solution is developed for a transient heat conduction equation in which a plane slab is heated by a bimodal distribution beam over the upper surface. In laser heat treatment of steel few methods are used to produce a wider and nearly uniform average irradiance profile. This may be achieved by a bimodal (TEM11) shaped laser beam. In this paper, Green function method is employed to derive an analytical solution for thermal field distribution induced by laser forming process. Then 3-D finite element modeling of a slab in the ANSYS code is used to model the thermal field of laser forming with bimodal beam distribution. The results show that bimodal beam is useful for obtaining a uniform heat intensity distribution.

A tautomeric equilibrium exists for quinoline-2-thiol and quinoline-2(1H)-thione. Quantum mechanical calculations predict the thione is the major tautomer and this is confirmed by the absorption spectra. The utility of quinolone-2-thiol/quinoline-2(1H)-thione as a chromophore for developing fluorescent sensors is explored. No fluorescence is observed when excited at absorption maxima, however a fluorescence increase is observed when exposed to HNO, a molecule of import as a cardiovascular therapeutic. Alkylated quinoline-2-thiol derivatives are found to be fluorescent and show a reduction in fluorescence when exposed to metals and changes in pH.