Specific Issues of Urban Sprawl in Bulgaria

The first conclusion is, no doubt, that processes of urban sprawl have emerged in Bulgaria during the last couple of decades and already have changed the suburban patterns in the outskirts of Sofia. This is a simple, but critically important conclusion, because so far Bulgarian planners have underestimated this threat and, even, have failed to identify it. The main reasons for this omission were due to lack of experience with similar problems and, mainly, to specific traditions relating to comparatively high, though typical European densities and compact urban forms. Yet, due to its unplanned nature and scattered forms, sprawl always generates un- sustainable urban processes. All facts and findings of previous studies and the present one confirm the second main conclusion that, undoubtedly, Sofia suburbanisation pattern is of Western type, so it is characterized by a number of associated problems and issues like overconsumption of land, inefficient use of infrastructure and other resources. At the same time, Bulgarian sprawl in many aspects is shaped by local traditions established in the course of centuries and (especially, the 20th century) by the specific historical development – both socio-economic and urban. Sofia’s new suburbs are more compact than typical Western suburbs and they are characterized by higher densities and higher levels of social mix and mix of uses. Eventually, the third main conclusion is that suburbanisation around Sofia and around other big cities in the country is speeding up and, thus, Bulgarian sprawl turns closer to the Western patterns. This means that policy measures are already needed to avoid associated problems, especially in view of the insufficient land resources of Bulgaria. Apparently, all these issues should be subject to thorough and in depth studies as next steps of research in this area in order to elaborate efficient instruments of relevant policies

Tribology in Ballroom Dance With Energy Consumption Analysis

Tribology phenomena are obviously present and have significant importance in most of human activities, processes and actions. Ballroom Dance as a common activitie with practically importance is not enough studied and analyzed from the tribological point of view. This paper presents an attempt in this direction dealing with study of tribology aspects by analyzing a couple of Standard and Latin ballroom dances with characteristic steps and choreography. This paper shows an approximate calculation of friction forces and torques caused by some common movements and their influence on interaction in foot floor interface. Besides the approximate calculation of friction loss, authors have measured and analyze the total energy consumption by making several experiments with corresponding equipment

Paleolinguistics brings more light on the earliest history of the traditional Eurasian pulse crops

Traditional pulse crops such as pea, lentil, field bean, bitter vetch, chickpea and common vetch originate from Middle East, Mediterranean and Central Asia^1^. They were a part of human diets in hunter-gatherers communities^2^ and are one of the most ancient cultivated crops^3,4^. Europe has always been rich in languages^5^, with individual families still preserving common vocabularies related to agriculture^6,7^. The evidence on the early pulse history witnessed by the attested roots in diverse Eurasian proto-languages remains insufficiently clarified and its potential for supporting archaeobotanical findings is still non-assessed. Here we show that the paleolinguistic research may contribute to archaeobotany in understanding the role traditional Eurasian pulse crops had in the everyday life of ancient Europeans. It was found that the Proto-Indo-European language^8,9^ had the largest number of roots directly related to pulses, such as *arnk(')- (a leguminous plant), *bhabh- (field bean), *erəgw[h]- (a kernel of leguminous plant; pea), *ghArs- (a leguminous plant), *kek-, *k'ik'- (pea) and *lent- (lentil)^10,11,12^, numerous words subsequently related to pulses^13,14^ and borrowings from one branch to another^15^, confirming their essential place in the nutrition of Proto-Indo-Europeans^16,17,18^. It was also determined that pea was the most important among Proto-Uralic people^19,20,21^, while pea and lentil were the most significant in the agriculture of Proto-Altaic people^22,23,24^. Pea and bean were most common among Caucasians^25,26^, Basques^27,28^ and their hypothetical common forefathers^29^ and bean and lentil among the Afro-Asiatic ancestors of modern Maltese^30^. Our results demonstrate that pulses were common among the ancestors of present European nations and that paleolinguistics and its lexicological and etymological analysis may be useful in better understanding the earliest days of traditional Eurasian crops. We believe our results could be a basis for advanced multidisciplinary approach to the pulse crop domestication, involving plant scientists, archaeobotanists and linguists, and for reconstructing even earlier periods of pulse history

On the torque transmission by a Cardan-Hooke joint

Proučavana je kinemtika i dinamika Kardan-Hukovog zgloba. Kinematička analiza se bazira na teoriji složenog kretanja krutog tela. Dinamička analiza Kardan-Hukovog zgloba je izvršena na bazi Lagranževih jednačina druge vrste. Kardan-Hukov zglob je analiziran u uslovima promenljive ugaone brzine pogonskog (ulaznog) vratila zgloba. Razmatrane su dve varijante zgloba: (1) ravan pogonske viljuške se poklapa sa ravni vratila; (2) ravan pogonske viljuške je normalna na ravan vratila. Izveden je izraz kojim se opisuje prenos obrtnog momenta Kardan-Hukovim zglobom. Izvedeni izraz sadrži članove koji potiču od inercije ulaznog i izlaznog vratila kao i od inercije krsta Kardan-Hukovog zgloba. Teorijska razmatranja su propraćena numeričkim primerom.Kinematics and dynamics of a Cardan-Hooke joint are investigated. Kinematic analysis is based on the kinematic chain rule for angular velocity vectors. Dynamics of the Cardan-Hooke joint is analyzed by means of the Lagrange equations of the second kind. The Cardan-Hooke joint is analysed under varying operating conditions, that is, it is assumed that the input shaft has variable angular velocity. Two cases are considered: (1) the driving yoke plane coincides with the plane of the shafts; (2) the driving yoke plane is normal to the plane of the shafts. An expression for torque transmission in a Cardan-Hooke joint in varying operating conditions was developed. The expression contains terms representing inertia of the shafts and the cross of the Cardan-Hooke joint. Theoretical considerations are accompanied by a numerical example