Further developments in the conflation of CFD and building simulation

To provide practitioners with the means to tackle problems related to poor indoor environments, building simulation and computational fluid dynamics can usefully be integrated within a single computational framework. This paper describes the outcomes from a research project sponsored by the European Commission, which furthered the CFD modelling aspects of the ESP-r system. The paper summarises the form of the CFD model and describes the method used to integrate the thermal and flow domains

Effect of Anode Dielectric Coating on Hall Thruster Operation

An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode

OPTIMAL CONTROL OF THE ALKYLATION PROCESS REACTORS

Recent studies show that one of the most important issues of static optimization of structurally complex non-stationary technological processes is the development of appropriate methods for problem decomposition. The issue of optimization of non-stationary alkylation processes and ways to solve the problems arising in this regard has been investigated in this paper. It is known that there are several ways to increase the economic efficiency of control systems for petrochemical technological processes. It includes checking of instruments and regulators, identify improvements in the control and monitor of performance, etc. One of the main ways to increase the efficiency of control systems for technological processes which depend on current conditions is to develop models and algorithms that allow control these processes in more optimal modes compared to current ones. In this regard, the presented article is relevant as it is dedicated to the development of optimal control algorithms for multistage petrochemical technological processes consisting of series-connected non-stationary technological devices

A review of advanced air distribution methods - theory, practice, limitations and solutions

Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review

Nucleic acid and protein extraction from electropermeabilized E. coli cells on a microfluidic chip

Due to the extensive use of nucleic acid and protein analysis of bacterial samples, there is a need for simple and rapid extraction protocols for both plasmid DNA and RNA molecules as well as reporter proteins like the green fluorescent protein (GFP). In this report, an electropermeability technique has been developed which is based on exposing E. coli cells to low voltages to allow extraction of nucleic acids and proteins. The flow-through electropermeability chip used consists of a microfluidic channel with integrated gold electrodes that promote cell envelope channel formation at low applied voltages. This will allow small biomolecules with diameters less than 30 A to rapidly diffuse from the permeabilized cells to the surrounding solution. By controlling the applied voltage, partial and transient to complete cell opening can be obtained. By using DC voltages below 0.5 V, cell lysis can be avoided and the transiently formed pores can be closed again and the cells survive. This method has been used to extract RNA and GFP molecules under conditions of electropermeability. Plasmid DNA could be recovered when the applied voltage was increased to 2 V, thus causing complete cell lysis

A systematic review of operating room ventilation

Ventilation systems are the primary way of eliminating airborne pathogenic particles in an operating room (OR). However, such systems can be complex due to factors such as different surgical instruments, diverse room sizes, various staff counts, types of clothing used, different surgical types and duration, medications, and patient conditions. OR ventilation should provide a thermally comfortable environment for the surgical staff team members while preventing the patient from suffering from any extreme hypothermia. Many technical, logistical, and ethical implications need to be considered in the early stage of designing a ventilation system for an OR. Years of research and a significant number of publications have highlighted the controversy and disagreement among infection specialists, design engineers, and ventilation experts in this context. This review article aims to provide a good understanding of OR ventilation systems in the context of air quality and infection control from existing research and provide multidimensional insights for appropriate design and operation of the OR. To this end, we have conducted a systematic review of the literature, covering 253 articles in this context. Systematic review and meta-analyses were used to map the evidence and identify research gaps in the existing clinical, practical, and engineering knowledge. The present study is categorized into six research focuses: ventilation system, thermal comfort, staff work practice and obstacles, door operation and passage, air cleaning technology, emission rate, and clothing systems. In the conclusion, we summarize the key limitations of the existing studies and insights for future research direction

Широкозахватный опрыскиватель с гибким отводом и летательными аппаратами для обработки посевов риса

The article presents the brief analysis of existing technical determinations for spraying, the surface injection of liquid solutions, in the course of which about 75 percent of pesticides used in agricultural production are injected in order to preserve the crop from pests, diseases and weeds. (Purpose of the study) To develop the wide-coverage sprinkler with extended operational and technological capabilities for the rice sowings. (Materials and methods) It has been established that the main criterion for the up-to-date creation of the technical equipment used for spraying is the reduction of norms of the working fluid consumption and the level of environmental pollution by pesticides and also that the domesticmachines for this use coming to the market have low technical performance indicators and insufficient reliability. (Results and discussions) The design of a new wide-coverage spraying machine with a flexible tap and vehicles for the spraying of rice and with extended operational and technological capabilities, containing two propulsion units (one with a current generator, the other with a solution tank and a pressure pipeline) has been suggested. They are equipped with the frames with tensioners and are kinematically connected to each other by a flexible carcase on which the vehicles and suspended nodes of the mud channel with spraying machines are placed. The spraying of the rice fields by vehicles confirms theexpediency of their application in the rice industry for the ensuring of significant reduction in the crop losses from plant diseases. The production of new chemicals with low consumption rates and enhanced biological activity served as the basis for the development of the proposed design of wide-coverage sprinkler to meet modern requirements for sprayers of this type and intended for the use in medium and large rice farms. (Conclusions) The use of the presented wide-coverage sprinkler will allow farmers to apply intensive technology of rice cultivation on rice farms, and it will significantly increase the effectiveness of protective measures and reduce the consumption rates of chemicals, as well as reduce haul costs and spraying of working liquid solutions. The adoption of new technologies and technical means of plant protection that meetmodern requirements are worthy of continued work on their improvement and, in particular, the creation of new technicalmeans of weed controlПриведен краткий анализ существующих технических решений для поверхностного внесения жидких растворов – опрыскивания, в процессе которого вносится до 75 процентов применяемых в сельскохозяйственном производстве ядохимикатов с целью сохранения урожая от вредителей, болезней и сорной растительности. (Цель исследований) Разработать широкозахватный опрыскиватель для посевов риса с расширенными эксплуатацион-но-технологическими возможностями. (Материалы и методы) Отметили, что основным критерием, отвечающим современным требованиям по созданию технических средств для опрыскивания, служит снижение норм расхода рабочей жидкости и уровня загрязнения окружающей среды ядохимикатами. Показали, что поступающие на рынок отечественные машины данного назначения имеют низкие технико-эксплуатационные показатели и недостаточную надежность. (Результат и обсуждение) Предложили конструкцию нового широкозахватного опрыскивателя для риса с расширенными эксплуатационно-технологическими возможностями, с гибким отводом и летательными аппаратами. В конструкцию включены два движителя (один с генератором тока, другой – с емкостью дляраствора и напорным трубопроводом). Они оснащены рамами с натяжителями и кинематически связаны между собой гибким остовом, на котором размещены летательные аппараты и подвесные узлы растворопровода с распылителями. Подтвердили целесообразность обработки рисовых полей летательными аппаратами для обеспечениясущественного сокращения потерь урожая от заболеваний растений. Предложили конструкцию широкозахватного опрыскивателя, отвечающего современным требованиям к опрыскивателям данного вида и предназначенного для применения в средних и крупных рисоводческих хозяйствах при использовании новых химических веществ с небольшими нормами расхода и усиленной биологической активностью. (Выводы) Провели теоретические расчеты, позволяющие обосновать конструктивно-технологические параметры разрабатываемого широкозахватного опрыскивателя, учитывающие основные факторы, оказывающие влияние на качество процесса опрыскивания. Показали, что использование представленного широкозахватного опрыскивателя позволит в рисоводческих хозяйствах применить интенсивную технологию возделывания риса, что существенно повысит эффективность защитных мероприятий и сократит нормы расхода химикатов, а также снизит затраты на транспортировку и внесение жидких рабочих растворо

Membrane Permeabilization by Oligomeric α-Synuclein: In Search of the Mechanism

Background: \ud The question of how the aggregation of the neuronal protein α-synuclein contributes to neuronal toxicity in Parkinson's disease has been the subject of intensive research over the past decade. Recently, attention has shifted from the amyloid fibrils to soluble oligomeric intermediates in the α-synuclein aggregation process. These oligomers are hypothesized to be cytotoxic and to permeabilize cellular membranes, possibly by forming pore-like complexes in the bilayer. Although the subject of α-synuclein oligomer-membrane interactions has attracted much attention, there is only limited evidence that supports the pore formation by α-synuclein oligomers. In addition the existing data are contradictory.\ud \ud Methodology/Principal Findings:\ud Here we have studied the mechanism of lipid bilayer disruption by a well-characterized α-synuclein oligomer species in detail using a number of in vitro bilayer systems and assays. Dye efflux from vesicles induced by oligomeric α-synuclein was found to be a fast all-or-none process. Individual vesicles swiftly lose their contents but overall vesicle morphology remains unaltered. A newly developed assay based on a dextran-coupled dye showed that non-equilibrium processes dominate the disruption of the vesicles. The membrane is highly permeable to solute influx directly after oligomer addition, after which membrane integrity is partly restored. The permeabilization of the membrane is possibly related to the intrinsic instability of the bilayer. Vesicles composed of negatively charged lipids, which are generally used for measuring α-synuclein-lipid interactions, were unstable to protein adsorption in general.\ud \ud Conclusions/Significance:\ud The dye efflux from negatively charged vesicles upon addition of α-synuclein has been hypothesized to occur through the formation of oligomeric membrane pores. However, our results show that the dye efflux characteristics are consistent with bilayer defects caused by membrane instability. These data shed new insights into potential mechanisms of toxicity of oligomeric α-synuclein species

Evaluating the thermal comfort performance of heating systems using a thermal manikin with human thermoregulatory control

© International Society of the Built Environment. © The Author(s) 2014. The evaluation of the local thermal comfort and application of thermal manikins can further assist the design and selection of heating systems. This study aimed at evaluating the thermal comfort performance of different heating systems using a newly developed thermal manikin with an enhanced thermal control. The heating systems for a workstation, included a conventional radiator (convector) mounted under the window, heated floor in the occupied zone and an infrared heater mounted to the ceiling. The experiments were conducted in a test room with a façade attached to a climate chamber to simulate outdoor winter conditions. In these experiments, the supplied power for the different systems was kept constant to independently quantify the differences in their thermal comfort performance at same energy consumption. The thermal manikin was deployed in the occupied zone to evaluate the local and overall thermal comfort under each system using the equivalent temperature (Teq) approach. The thermoregulatory control used in the manikin operation is based on a model of human thermoregulation that interacts accurately with the surrounding environment through real-time measurements. The results showed that at the same energy consumption of the different systems, the variations in local thermal comfort levels were up to 1 on the comfort scale