Why Does Cronobacter sakazakii Survive for a Long Time in Dry Environments? Contribution of the Glass Transition of Dried Bacterial Cells

The mechanical glass transition temperature ( T g ) of dried Cronobacter sakazakii cells varied depending on differences in drying methods and water activity (a w ) levels. Because the T g of the dried bacterial cells varied depending on the drying method and a w , the T g will play an important role as an operational factor in the optimization of dry food processing for controlling microbial contamination in the future.

Advances in operating capacity and life time of centrifugal cast pipes for high-temperature pyrolysis of NRC “Kurchatov Institute” – CRISM “Prometey”

On the basis of expert examinations of spent pipes metal operated as coil-pipes at pyrolysis furnaces, heat-resistant alloys and technologies for manufacturing standard products from them have been developed. The service characteristics of the developed alloy 45Kh32N43SB and its welded joints at temperatures of 1100 and 1150°C have been investigated. It is shown that the alloy has structural stability and the ability to resist high-temperature creep at operating temperatures up to 1150°C. A method has been developed for assessing the resource of pipe elements, taking into account the peculiarities of its operation, as well as crack-like defects in the pipe material. The reasons for the significant deformation and damage of the crossover piping, leading to the premature failure of the coils, have been found. The most significant operational factor of damage to the heat exchangers at pyrolysis plants has been identified.

Experimental investigation of structural and operational factor effects on speed performance of wave cleaving catamarans

В статье приводятся результаты экспериментального исследования влияния конструктивных факторов на ходовые качества перспективного волнорассекающего пассажирского катамарана. Цель работы – поиск принципиальных технических решений по облику катамарана, обеспечивающих повышенные ходовые качества на тихой воде, в условиях волнения и экономическую эффективность. Оценено влияние скорости хода на ходовую посадку, гидродинамическое сопротивление, буксировочную и потребную мощность волнорассекающего катамарана. Выявлена эффективность применения транцевого интерцептора на волнорассекающем катамаране. Обсуждается рациональный выбор перемещения (выдвига) транцевого интерцептора при заданных значениях водоизмещения и эксплуатационной скорости. Выявлена целесообразность перехода от двулапых кронштейнов гребных валов к однолапым. Определено изменение потребной мощности при переходе от двулапого кронштейна к однолапому. Дана количественная оценка влияния выступающих частей (рулей и кронштейнов) на буксировочное сопротивление модели. Оценено взаимное влияние выдвига интерцептора и угла статического дифферента на характеристики ходкости при движении катамарана со скоростью экономического хода и эксплуатационной скоростью. Выявлена зависимость дополнительного буксировочного сопротивления модели на волнении от формы соединительного моста катамарана. Результаты исследований использованы при проектировании современного экологичного пассажирского катамарана проекта «Ecocruiser». The paper presents results of experimental study of structural factor effects on speed performance of a promising wave-cleaving passenger catamaran. The work purpose consists in searching for basic engineering solutions on the catamaran appearance that provide increased speed performance in still water and in seas, as well as economical efficiency. Effects of travel speed on operating trim, flow resistance, towrope power and power requirements of a wave-cleaving catamaran are evaluated. Effectiveness of using a transom intercepter in a wave-cleaving catamaran was identified. Rational selection of transom intercepter movement (advance) at specified displacement and operational speed values are discussed. Expedience of transition from two-leg propeller struts to single-leg ones is shown. Change of the power requirements at transition from two-leg propeller struts to single-leg ones is evaluated. Effects of projecting parts (rudders and propeller struts) on the model towrope resistance are evaluated quantitatively. Mutual effects of intercepter advance and static trim angle on the propulsion qualities under catamaran operation at economical and service speeds are evaluated. Dependence of the model additional towrope resistance in seas on the catamaran cross-deck structure shape are derived. The investigation results were used for design of a state-of-art ecological passenger catamaran “Ecocruiser”.

Optimization of reverse osmosis operational conditions to maximize ammonia removal from the effluent of an anaerobic membrane bioreactor

RO enables the recovery of clean water and ammonium in anaerobic membrane bioreactor effluent. pH governs the ammonia speciation and membrane surface charge and is the key operational factor that affects the total ammonia rejection efficiency of RO.

Classification of operational factors leading to premature failures of agricultural machinery parts

The article presents the material on the analysis of factors affecting the decrease in the functionality of agricultural machines and leading to the occurrence of failures. A classification of operational factors is presented, taking into account the influence of factors on each other. The factors considered were classified into different interaction groups and presented as a hierarchical fl owchart. The proposed classification of the considered operational factors is necessary to establish the relationship of the operational factor with the most significant group of factors and, accordingly, with the main elements determining the life of units and units of agricultural machinery.

The work of rails under conditions of various average static axial loads of rolling stock

The analysis of failure of unhardened and heat-strengthened R65 rails under operating conditions in the tangent sections of the track is presented taking into account the influence of the most important operational factor - the average static axial loads of the rolling stock. Non-reinforced R65 rails in the jointed track on the 12.5 m long wooden sub-rail base were considered based on the results of their single replacement in the entire range of their failures. The work of rails under operating conditions is estimated at average static axial loads of rolling stock as 7.5, 9.5, 16.5 and 19.5 tf (73.55, 93.16, 161.82 and 191.21 kN) at all stages of the tonnage at each load. The influence of the average static axial loads of the rolling stock on rail failure in specific operating conditions has been revealed. The features of the change in the intensity of rail failure are considered at all stages of their operation, both for the specified and for the average network level of the static load. The obtained statistical data on the effect of axial loads of rolling stock on the operation of rails can be used in the practice of track maintenance. In conditions of increasing axial loads up to 25, 27 tf, it is necessary to use rails of the appropriate quality; also it is expedient to create new rails for such operating conditions. It is necessary to perform an evaluation of the real operational qualities of the rails in order to use the rolling stock with the increased axial loads (25, 27 tf) in the transportation process in the most efficient way. In the long term, the results of such studies will be aimed at improving the operation of the systems for running track and railway car complexes.

Underwater observations of seal–fishery interactions and the effectiveness of an exclusion device in reducing bycatch in a midwater trawl fishery

Interactions between seals and midwater trawl operations in the Australian Small Pelagic Fishery are common and can be lethal. The nature of interactions and effectiveness of a seal exclusion device (SED) in mitigating lethal interactions was assessed using underwater video. Recent fishing activity and the phase of the trawl operation significantly influenced interaction rates; interactions increased with the amount of recent trawl activity and were highest while the trawl was being set. Most seals accessed the trawl via the net entrance and exited via an escape opening located at the base of the SED. The size of the escape opening was the only operational factor that influenced mortality rates — simply enlarging the escape hole reduced lethal interactions by 79%. However, since all deceased seals dropped out of the net before they were brought on board, they would have gone unobserved without video monitoring. Limiting the concentration of fishing activity in space and time and refinement of the SED design, in particular to address dropouts, is recommended if mortality rates are to be reduced.