Researches show that one of the most effective factors on bridges destruction is bridge piers scour. One of the methods used to reduce scour around bridge piers is installing collar. The collars protect the river bed against vortex flow in the vicinity of the piers. The role of collar as a control structure of bridge pier scour was investigated along with the effect of its shape. Experiments showed that the dimensions of the collar have a significant effect on its performance. The results showed that its performance improves with increasing the dimensions of the collar. By comparing the two types of collars, it was found that collars with (3×6) D elliptical dimensions have better performance in reducing scour than collar with (3×4) D dimensions. Larger collars performed better because they prevented the movement of sediments due to vortex activity at collar downstream. On the other hand, with the reduction of roughness in collar surfaces from 40% to 15%, the amount of scour reduction increases from 39% to 58% compared to the base without collar.

The bridge pier scour is one of the major causes of bridge destruction worldwide. In spite of extensive research in this field, the study of this topic has always been of interest to researchers and it is necessary to study different methods to counter it. The collar is a simple and inexpensive structure for protection against bridge pier scour. In this study, the effect of collar size and height on bridge pier scour and determination of the best collar performance conditions in steady and unsteady flow conditions were investigated. The experiments used three different collar sizes and three different mounting heights relative to the substrate surface. After calculating the percentage of scour reduction in all test cases and comparing them, Investigation of time evolution diagram of scour hole and comparison of maximum depth of scour created in different states, It was found that increasing the size of the collar and decreasing the height of the collar installation relative to the substrate surface resulted in a further decrease in the depth of the bridge pier scour and this changes was more evident in the unsteady flow state. Also by comparing the two variables of size and height of collar installation, it was found that the height of collar with dimensionless ratio H/D=0. 5 in steady and unsteady flow had the best performance and the greatest effect in reduction scour around bridge pier.

Every year river flooding causes serious damage to the bridges at the time needed most. One of the most effective factors causing bridge failure is scouring around the piers in a river bend. One of the methods to decrease scouring around the bridge piers is fitting them with a coller on the piers. The collars protect the river bed against vortex flow in the vicinity of the pier base. An experiment was conducted to study lab flumes made of Plaxiglass with a 180 degree bend and 2.8 m central radius and a 0.6 m width. In this study, a 6cm diameter pier was placed with a circular collar with four different collar sizes in one position in bend with constant discharge and depth under clear-water conditions. The collar was placed at four different elevations. The soil material had a diameter of d50=2mm and geometric standard deviation of sg=1.3. The results of the model study indicated that the maximum depth scouring was highly dependent on the experimental duration. It was observed that as the size of a collar plate increases, the scour decreases. So, minimum depth of scour is dependent on the 3D coller and -0.1D elevation. Circular collar results in maximum reduction in scour depth (93%) compared with no circular collar.

More than six decades past since the important and everlasting work of Edwin H. Sutherland, The famous professor of penal sociology in the U.S.A, entitled "white-collar crime", has been published. Sutherland explained this topic in terms of its importance for the civil society of the U.S.A, and opened a new way which was later pursued by the celebrated criminologists. From the criminologists point of view, white- collar criminals who have no ethical conscience, enjoy high ability to commit a crime on one hand, and their conformitibility is in a high level on the other hand. This point expresses the probable harms of these good- looking criminals and their dangerous state. White- collar criminals belong to high social classes, they enjoy power and effectual influence. They commit crimes such as fraud, embezzlement, bribery, forgery, abuse of credit cards, efc. In Sutherlands definition, "white-collar crime" is a crime committed by a person of high status in the course of occupation. They are called white - collar criminals, because of their plausible face, public reputation, intelligence and being under social acceptability. The effects of their criminal acts are in a manner, which their results predominantly remain for a long time. However , its necessary to study the white- collar crimes whit respect to their destructive effects on communities through a comprehensive approach, especially from criminologicaly aspects.

In addition to the strength and stability of the bridges, designers and engineers pay much attention to bridge appearance and scenery, which led to build bridges with inclined piers to the flow. Therefore, studying the hydraulic conditions and scour countermeasure of inclined bridge piers is necessary. In this study, the effect of collar on scour reduction at the base of vertical and angled cylindrical piers was investigated. The collar installed at the surface of the sediment bed for vertical and inclined piers. The result of experiments showed that the highest scour depth belongs to the inclined bridge pier toward the upstream direction, which is 15% more than the vertical pier. However, the maximum scour depth in front of the angled pier toward downstream was measured to be about 30% lower than the vertical pier. For the pier inclined toward the upstream direction, the collar reduced the scour in front of the pier about 63%. The collar for the pier inclined toward the downstream direction decreased the scour by about 67%. The result shows that the installation of collars can have a high effect on reducing the scour depth for inclined piers.

The most criminological researches have focused on conventional violent crimes in recent years. However, we have a little information about victimization of white-collar crime and a few researches have conducted in this area.Critical criminologists are interested in victimology of white-collar crime.They called victim of white-collar crimes as invisible victims. The nature of white-collar victimization is financial although it may lead to serious physical harms. Patterns of victimization in conventional crimes are different to patterns of white-collar crime victimization although these patterns are similar to each other to some extent. Patterns and types of victimization in white-collar crimes are varied by gender, age, and socio-economic class.Beyond the direct economic costs, white-collar crimes have many significant indirect costs which are harmful as well as direct ones.

Negative personality characteristics have deep relationships with crime and wrongdoing. Personality of each person is formed based on their personality characteristics and if these negative personality characteristics grow, they will lead towards wrongdoings. This study intends to investigate white-collar criminals’ personality characteristics, not only to identify them precisely but also to prevent and correct them. Therefore; this study deals with white-collar criminals’ personality characteristics. This descriptive-analytical study uses survey techniques and its data collection tool is based on library and digital data methods. The target society includes all white-collar criminals. With regards to this study, the question which was answered is that what characteristics do these white-collar criminals have? The findings include: certain personality characteristics are effective in perpetrating and setting the stage for crimes. Some others which were expressed as white-collar criminals’ personality characteristics in the past studies, are not their unique ones and other category of characteristics are in conflict with white-collar criminals’ personality characteristics and can not be considered as their personality characteristics, like having duties that do not corresponds to criminality. As a result, personality characteristics have relative relationships with perpetrating crimes.

The explanation and categorization of white –collar crimes have been analyzed in an interdisciplinary manner by criminologists, lawyers, sociologists, management, etc. According to body metaphor, white-collar crimes are called phosphorus crimes. These crimes are often done by high and middle class people who are working in administrative and organizational departments. Considering damages resulting from middle-class crimes, such crimes have been reported forty times more than those of street crimes, few attempts have been made for their discovery and investigation. The purpose of the current paper was to investigate criminological approaches and typology of white –collar crimes. While using a documentation method, the present paper analyzed and explained the typology of white-collar crimes through positivism, constructionism and meta-theoretical approaches. Meanwhile, it investigated the relationship between these sorts of crimes and other social crimes.

Scouring around bridge piers causes serious damages to these structures all around the world every year. In order to control this phenomenon, riprap is placed around the piers to increase streambed resistance (direct method). However, in indirect method, some partitions such as collar slot and submerged vanes are used to reduce scouring caused by horseshoe vortex and downstream flow. In this research, effect of two types of square and circular collar on a single cylindrical model has been investigated. The results showed that using the two kinds of collar, especially below bed level decreased the scour depth. Square collar was more effective than circular one in decreasing the scour depth. The square and circular collars showed 70% and 50% decrease in the rate of scour depth, respectively, as compared to pier without any collar.