In this paper, an alternative approach in operational Modal analysis is presented, utilizing image processing technique and transmissibility functions. Imaging sensors do not impose additional mass on the structure due to their non-contact nature, while transmissibility functions, independent of excitation type, can directly extract mode shapes. The innovation of this research lies in combining these two techniques to record dynamic responses and identify Modal properties. To capture the temporal response history from video signals, the block-matching method with sub-pixel accuracy was employed. Validation was conducted by recording the response of the tip of a cantilevered steel beam subjected to impact excitation, using a high-speed camera and a laser vibrometer, simultaneously. The RMSE plots in the time domain and the PSD in the frequency domain indicate high accuracy of this method. Using this approach, the displacement time histories of various points on the structure were extracted from the video signals, and the Modal properties, including natural frequencies, damping ratios, and mode shapes, were identified using the transmissibility matrix method. The results obtained from the proposed method were compared with the stochastic subspace identification (SSI) method and analytical solutions. The findings reveal the accuracy of the Modal identification approach introduced in this article. The highest relative error in estimating the natural frequencies of the first and second modes, compared to the values from the laser method, are 0.19% and 0.13%, respectively, and in comparison to the analytical values, they are 0.34% and 1.5%, respectively.

Modal analysis is a process of describing a structure in terms of its natural characteristics which are the frequency, damping and mode shapes-its dynamic properties [1]. The change of Modal characteristics directly provides an indication of structural condition based on changes in frequencies and mode shapes of vibration. This paper presents results of an experimental Modal analysis of beams made with different materials such as Steel, Brass, Copper and Aluminum. The beams were excited using an impact hammer excitation technique over the frequency range of interest, 0–2000 Hz. Frequency response functions (FRFs) were obtained using OROS vibration analyzer. The FRFs were processed using NV Solutions Modal analysis package to identify natural frequencies, Damping and the corresponding mode shapes of the beams.

Improving participation in voluntary activities in Iran is important because increasing productivity among young people, given the country's young population, contributes to community sustainability. Therefore, a better understanding of volunteer motivation in Iranian youth is needed. The Volunteer Functions Inventory (VFI) for assessing volunteer motivations has good psychometric properties and is adapted to several languages, but no validated Iranian translation yet exists. The purpose of this study was to investigate the psychometric characteristics of voluntary functions inventory in members of Iranian Red Crescent Society. Sample size was 595 members of Youth Organization of Iranian Red Crescent Society from 31 provinces and 175 cities of Iran that were selected by multi-stage cluster sampling method and responded to voluntary functions inventory. Data were collected using a demographic sample and voluntary functions inventory (VFI). Confirmatory factor analysis using principal components method was used for data analysis. The results of the present study showed that the voluntary functions inventory had validity and reliability. Also, the factor structure showed that 29 items and 6 factors well assess people's attitudes to volunteering, and the structure of this inventory was well-fitted and confirmed all goodness of fit models. The present study provides the use of the Iranian translation of the Voluntary Functions Inventory (6 scales and 29 items) to assess volunteer motivation among young Iranian volunteers.

There is a famous idea in Modal epistemology according to which conceivability of a proposition is a good guide for its possibility. Yablo (1993) persents a model for justification of Modal beliefs, based on which Conceivability of a proposition is evidence for its possibility. Van Inwagen (1998) believes that if we accept Yablo’s model, we have to accept Modal skepticism. To argue for this, Van Inwagen examines the Modal status of the proposition that transparent iron exists on Yablo’s model. Van Inwagen claims that this proposition is undecidable on Yablo’s model. So we cannot have a justified belief that it is possible that transparent iron exists. If van Inwagen’s claim about the Modal status of the proposition that transparent iron exists is correct, Yablo’s model, one might think, faces a serious problem. For if we generalize van Inwagen’s analysis of the proposition that transparent iron exists, we have to count intuitively possible propositions, propositions the Modal status of which can be intuitively known as possible, as undecidable. But it is quite plausible that our beliefs about the possibility of some intuitively possible propositions are justified, so these propositions are not undecidable. I will, however, argue that van Inwagen’s analysis of Modal status of the proposition that transparent iron exists cannot be generalized to all (or most) intuitively possible propositions. And therefore it is possible to accept at the same time both Yablo’s justification model and van Inwagen’s analysis about the Modal status of propositions like transparent iron exist.

In this study, the effects of delamination size and location on vibration characteristics of laminated composite beams are investigated via analytical, finite element and experimental methods. In the analytical method, the delaminated beam is divided into four interconnected beams and the interaction of two subbeams at the location of delamination is simulated by both constrained and free mode models. The effect of bending-extension coupling is taken into account in the analytical formulation. In finite element method, Modal analysis is performed on the delaminated composite beams with different delamination sizes and locations and various boundary conditions using commercial finite element software, ABAQUS. Both free and constrained mode models are simulated in the finite element model using suitable interactions, nonlinearities and friction conditions. Analytical and finite element results of both constrained and free mode models are compared for a symmetric cross-ply delaminated composite beam with various sizes and locations of delamination. Also, in order to investigate the effects of axial location of relatively small delamination on the first three natural frequencies, Modal tests are done on glass/epoxy composites for various boundary conditions. Results show that analytical, finite element and experimental frequencies have good agreement with each other.

This paper is concerned with the finite element analysis and Modal testing of an industrial radial flow impeller. The goal is to determine and verify the vibration characteristics of the impeller using both experimental and analytical techniques.The finite element model of the impeller with tapered blades was built using a 3D solid element. The convergence properties of the FE model was then verified by mesh refinement and mass distribution methods. Next, a pre-test plan was performed before conducting a Modal test in order to select the proper suspension points, driving point(s) and response points on the  impeller.Impact testing using hammer excitation and laser Doppler vibrometer (LDV) response measuring techniques were used to measure the vibration properties of the impeller. Using a scanning laser Doppler vibrometer enabled the backplate modes to be described in terms of their nodal diameter components. The nodal diameters versus natural frequencies graph was then compared with the same results obtained from FE and hammer testing and showed good agreement. Finally, a parametric study was conducted on disc thickness, blade thickness, blade trailing, leading edge profiles and blade mistuning. It was found that the effect of varying disc thickness on the lower modes of the impeller was not significant. However, significant natural frequency shifts were observed for the higher modes. It was also concluded that varying the blade leading edge position had a marked effect on the natural frequencies while the lower modes were somehow insensitive to the variation of trailing edge position.

The relationship between term-subject and subject in the attrebutive theorem is (‘عقدالوضع’-Aghd Al-Vaz). According to Al-Razi pruport, the Modal of that relationship in Al-farabi’s viewpoint is contingency but Al-Tousi says Al-Farabi’s viewpoint is possibility Modal. So at last, two of them don’t accept Al-Farabi’s holistic view. On the other hand both of them say that Avicenna, however, accepts actuality Modal for ‘Aghd Al-Vaz’ in every theorem and this is the true Modal. So Al-Farabi doesn’t talk about the Modal of Aghd Al-Vad completely but it is understood that he looks at the relationship as a kind of theorem which accepts Modals. Therefore, Avicenna doesn’t accept actuality Modal for all theorems. So in this article, first of all we are going to check that possibility Modal and contingency Modal as a Modal of Aghd Al-Vaz is accepted by both Al-Farabi and Avicenna; in the second step we are going to show that the critic of Al-Razi and Al-Tousi in Al-Farbi is not seemed true.

Background and Aim: Job enrichment is a method that has been used to increase employee satisfaction and work motivation. The Hackman and Oldham job characteristics model (1976) has served as the foundation for many job enrichment efforts. In particular, a considerable amount of research has been devoted to the study of the job characteristics-job satisfaction relations. Te purpose of this study was to statistically determine the relation between job characteristics and job satisfaction among employees of hospitals affiliated to Tehran University of Medical Sciences (TUMS) in 2007. Materials and Methods: This study was a cross-sectional one, including 6 TUMS-affiliated hospitals-Emam, Shariati, Baharlo, Ziaeian, Madaen and Azadi. The sample size was 400, consisting of 200 administrative employees (50%), 151 nurses (38%) and 49 physicians (12%). The random sampling and stratified proportional sampling methods were used to select the hospitals and interviewees, respectively. Two questionnaires were developed and used to identify job characteristics and job satisfaction: 1) job diagnostics surveys (JDS) and 2) Hertzberg's job satisfaction questionnaire. The reliability of the questionnaires was ascertained by test-retest using the Pearson correlation coefficient (r = 0.88). Linear-by-linear association and ordinal logistics regression analysis were used for analyzing the data gathered.Results:The relations between the Motivational Potential Score (MPS) and job characteristics (except for feedback) with job satisfaction were statistically significant (p<0.05). Task identity was the most effective determinant of job satisfaction. Conclusion: It appears that all the job characteristics (except feedback) are important determinants of job satisfaction of the hospital employees. Although the work environment is in need of restructuring, it is important to note, from a positive perspective, that the job characteristics discussed in this study are readily amenable to change job satisfaction at the organizational level.

In this article, first we define a Kripke semantics for normal Modal Logic with a binary operator and we introduce a system K^2 which is sound and complete for this semantics. Then, we will introduce two translations and show that binary normal Modal logic K^2, and unary normal Modal logic K, i.e. Modal logic with one binary operator, are very closely related by these two translations. We call a translation a faithful interpretation if provability is preserved in both directions. So, with this terminology we will show that these two translations are faithful interpretation of K into K^2 and vice versa. A logic extending K will be a set of formulas containing K closed under its rules and uniform substitution. A logic extending K^2 is similarly defined. Finally, we will prove that the classes of logics extending K and K^2 are closely related as well and there is a 1-1-correspondence between the logics extending K and extending K^2.

In the present paper, we are to put forth a paradigm for the systematic study of Modality in Persian. With this end in view, we consider Modality as a linguistic phenomenon that can be expressed at the level of sentence, at the level of constituents smaller than sentence and/or at the level of discourse. In such a system where sentential Modality, sub-sentential Modality and discourse Modality are the main categories, each and every Modal element can be studied with respect to its phonological, morphological, syntactic, semantic and pragmatic properties. Previous studies, meanwhile, have morpho-syntactically limited Persian Modal system to Modal verbs, Modal adverbs and past tense, and among different aspects of Modality, have mainly focused on semantic properties of Modal elements. In the present pages, employing the proposed paradigm and introducing the three semantic dimensions of Modal force, Modal base and ordering source, and with regard to the literature on Persian Modal system, we introduce Modal nouns and Modal adjectives to this system and briefly explain the semantic and morphological properties of Persian Modal adjectives as well as some of the restrictions imposed on the nominal complements of these adjectives.