A VARIABLE SAMPLING FREQUENCY CUMULATIVE SUM CONTROL CHART SCHEME

This study uses Monte Carlo simulation to examine the performance of a variable frequency sampling cumulative sum control chart scheme for controlling the mean of a normal process. The study compares the performance of the method with that of a standard fixed interval sampling cumulative sum control chart scheme. The results indicate that the variable frequency sampling cumulative sum control chart scheme is superior to the standard cumulative sum control chart scheme in detecting a small to moderate shift in the process mean

Short-time procedure for fatigue assessment of beech wood and adhesively bonded beech wood joints

Timber as a structural material has experienced a revival for aspects related to sustainability, positive effect on interior building and increased architectural possibilities. To overcome a series of limitations related to partly obsolete traditional techniques, timber engineering sets high expectations on adhesive bonding as a joining method. Research on adhesively bonded timber joints has proven their superiority over mechanical fasteners in terms of strength and stiffness. Research on methods to design adhesively bonded timber joints under static loads is currently ongoing and significant progress has already been achieved. The topic of fatigue behaviour, however, has only been addressed very rarely, largely because “classical” methods for fatigue assessment based on Woehler curves, is extremely time-consuming. This paper aims to fill this gap by describing and validating an advanced time- and cost-efficient approach to quantify the behaviour of bonded timber joints under fatigue. Therefore the fatigue behaviour of beech wood as base material and adhesively bonded beech wood joints as structural elements were investigated by means of a short-time procedure. In this approach, cyclic tests with a stepwise increase of the stress amplitude were performed while the plastic strain amplitude was measured. The plastic strain amplitude gives reliable signals for an estimation of the fatigue strength. This is validated by traditional cyclic tests with constant stress amplitudes. It could be shown that the testing approach provides reliable results and has a high potential in time and cost savings for wood and adhesively bonded wood joints

БАКТЕРИЦИДНА АКТИВНІСТЬ НОВИХ ТИПІВ ЧЕТВЕРТИННИХ АМОНІЙНИХ СОЛЕЙ НА ОСНОВІ НОВОКАЇНУ

On the basis of knows biologically active amine – Novocain mono- and bis-Quaternary ammonium derivatives have been synthesized. Antibacterial and antifungal activity of the drugs as to the test cultures of museum and freshly extracted from patients shtams of various genera and species of microorganisms, have been studied. The degree of activity and spectrum of antimicrobial action of eight of the synthesized compounds in vitro have been defined. The minimum bacteriostatic concentration of drugs as to the test cultures of Staphylococcus were in the range of 0.24-125.0 mkg/mg.На основании известного биологически активного амина – новокаина синтезировано ряд моно- и бис-четвертичных аммониевых производных. Исследовано бактерицидную и противогрибковую активность препаратов относительно тест-культур музейных и свежевыделенных от больных разных родов и видов микроорганизмов. Определено степень активности и спектр антимикробного действия, восьми синтезированных соединений in vitro. Минимальные бактериостатические концентрации препаратов относительно тест-культур стафилокока находились в пределах 0,24-125,0 мкг/мл.На основі відомого біологічно активного аміну – новокаїну синтезовано ряд моно- та біс-четвертинних амонійних похідних. Досліджено бактерицидну та протигрибкову активність препаратів відносно тест-культур музейних і свіжовиділених від хворих штамів різних родів і видів мікроорганізмів. Встановлено міру активності та спектр антимікробної дії восьми синтезованих сполук in vitro. Мінімальні бактеріостатичні концентрації препараті відносно тест-культур стафілокока знаходиться у межах 0,24-125,0 мкг/мл