Retractable type fall arresters are part of the equipment used for protecting people against falls from a height. They are an intermediate part between full body harness worn by a man and the structural anchor at the worksite. The most important task of retractable type fall arresters is to arrest people's falls and to reduce their harmful consequences. Information received from users as well a...

we call a module  essentially retractable if homr for all essential submodules n of m. for a right fbn ring r, it is shown that: (i)  a non-zero module  is retractable (in the sense that homr for all non-zero ) if and only if certain factor modules of m are essentially retractable nonsingular modules over r modulo their annihilators. (ii)  a non-zero module  is essentially retractable if and on...

abstract this paper by reviewing the main examples of small to medium-scale retractable roof structures covering building courtyards is to present an innovative rigid retractable roof system employing spatial frames for a courtyard of an existing building in tabriz islamic art university. the courtyard is currently used for temporary exhibitions and gatherings whenever permitted by environmenta...

Con el fin de estudiar fenómeno la retracción acentual en inglés como segunda lengua (L2), presente investigación se lleva a cabo un análisis acústico duración, intensidad y frecuencia fundamental. Las mediciones incluyen casos con presencia ausencia choque palabras acento retractable no-retractable. Se computan datos obtenidos manera experimental aprendientes contexto instrucción formal y, est...

A retrospective study was conducted of 91 boys who had had a non-retractable but non-fibrosed prepuce treated by retraction under general anaesthesia. Of the 79 boys who had had symptoms, 67 (85%) obtained relief. Twelve of the 91 patients were later circumcised because of continuing problems. Retraction of the foreskin alone is a simple and effective alternative to circumcision in managing mos...

Vigorous plant growth without sunlight is routinely achieved in commercial hydroponic lettuce and tomato production using electric lamps. This same technology can be used to maintain live turf grass in closed athletic stadiums. It can also be used to supplement natural sunlight in retractable roof stadiums. The challenge is to determine the optimal combination of genetic characteristics and env...

An automaton A is called a retractable automaton if, for every subau-tomaton B of A, there is at least one homomorphism of A onto B which leaves the elements of B fixed (such homomorphism is called a retract ho-momorphism of A onto B). We say that a retractable automaton A=(A,X,δ) is Boolean-type if there exists a family {λ B | B is a subautomaton of A} of retract homomorphisms λ B of A such th...