Ultra-low threshold lasing through phase front engineering via a metallic circular aperture

Semiconductor lasers with extremely low threshold power require a combination of small volume active region with high-quality-factor cavities. For ridge lasers with highly reflective coatings, an ultra-low threshold demands significantly suppressing the diffraction loss at the facets of the laser. Here, we demonstrate that introducing a subwavelength aperture in the metallic highly reflective coating of a laser can correct the phase front, thereby counter-intuitively enhancing both its modal reflectivity and transmissivity at the same time. Theoretical and experimental results manifest a decreasing in the mirror loss by over 40% and an increasing in the transmissivity by 104. Implementing this method on a small-cavity quantum cascade laser, room-temperature continuous-wave lasing operation at 4.5 μm wavelength with an electrical consumption power of only 143 mW is achieved. Our work suggests possibilities for future portable applications and can be implemented in a broad range of optoelectronic systems.

Electricity Usage Monitoring Based On Internet of Things

Electricity monitoring systems have long been used in industrial scenarios such as process scheduling and distribution. This monitoring system needs to be developed for domestic use such as in homes and shops. In recent times, the electricity demand has increased in households with the use of different appliances. The advent of technologies such as the Internet of Things (IoT) has made real-time data acquisition and analysis possible. This project is designed to control and monitor household electricity consumption via smartphones using the ESP8266 Wi-Fi module as a communication protocol and the Blynk application as a private server. The used wifi module provides notification through the Blynk application. The system uses an Arduino Mega2560 microcontroller to control all devices in this project. For monitoring the energy usage, a current sensor type Split Core Current Transformer (SCT013) was used. From the experimental results, it is confirmed that the system is capable of monitoring the whole house’s electrical usage easily. With this system in place, end-users are provided with proper awareness and able to plan their home’s electrical consumption pattern effectively.

Application of Artificial Neural Networks for Virtual Energy Assessment

A Virtual energy assessment (VEA) refers to the assessment of the energy flow in a building without physical data collection. It has been occasionally conducted before the COVID-19 pandemic to residential and commercial buildings. However, there is no established framework method for conducting this type of energy assessment. The COVID-19 pandemic has catalysed the implementation of remote energy assessments and remote facility management. In this paper, a novel framework for VEA is developed and tested on case study buildings at the University of Melbourne. The proposed method is a hybrid of top-down and bottom-up approaches: gathering the general information of the building and the historical data, in addition to investigating and modelling the electrical consumption with artificial neural network (ANN) with a projection of the future consumption. Through sensitivity analysis, the outdoor temperature was found to be the most sensitive (influential) parameter to electrical consumption. The lockdown of the buildings provided invaluable opportunities to assess electrical baseload with zero occupancies and usage of the building. Furthermore, comparison of the baseload with the consumption projection through ANN modelling accurately quantifies the energy consumption attributed to occupation and operational use, referred to as ‘operational energy’ in this paper. Differentiation and quantification of the baseload and operational energy may aid in energy conservation measures that specifically target to minimise these two distinct energy consumptions.

Power consumption management method objects of the regional electrotechnical complex based on the accounting of an additional resource

В настоящей статье рассматривается метод управления электропотреблением объектов регионального электротехнического комплекса на основе учёта добавочного ресурса. Актуальность его разработки обусловлена существующими тенденциями развития цифровой экономики во всех отраслях региональной экономики, в том числе - в припортовых комплексах региона. Важной составляющей современной цифровой экономики выступает цифровая энергетика, позволяющая регулировать управление бизнес-процессами в энергетической сфере. Обеспечение электроэнергией регионального припортового комплекса осуществляется с помощью двух подсистем регионального электроэнергетического комплекса: регионального транспортно-сетевого комплекса и регионального электротехнического комплекса. Важной задачей развития цифровой энергетики является разработка и внедрение цифровых сервисов. На сегодняшний день в региональных транспортно-сетевом и электротехническом комплексах внедрено значительное число цифровых сервисов. Однако они носят преимущественно «учётный» характер, в результате чего не способны в полной мере реализовать управление энергетическими процессами, существенно сократить затраты и повысить уровень энергоэффективности. Предлагаемый метод включает в себя модель и методики, позволяющие установить границы начала и завершения бифуркационных процессов, реализовать прогнозирование электропотребления объектов РТСК и РЭК на основе учёта добавочного ресурса и осуществить режимное нормирование электропотребления объектов, не нарушая технологического процесса. Применение данного метода может быть осуществлено в рамках динамического моделирования процесса электропотребления, исследования бифуркационных процессов, а также в качестве теоретической основы для создания сервисного программного обеспечения цифровых платформ управления электропотреблением для РТСК, РЭК и региональных припортовых комплексов. This article discusses the method of managing the electrical consumption of a regional electrical complex based on the accounting of an additional resource. The relevance of its development is due to the existing trends in the development of the digital economy in all sectors of the region, including in regional port complexes. An important component of the digital economy is digital energy, which allows regulating the management of business processes in the energy sector. The provision of electricity to the regional port complex is carried out with the help of two subsystems of the regional electric power complex: the regional transport and network complex and the regional electrical complex. An important task of the development of digital energy is the development and implementation of digital services. To date, a fairly large number of digital services have been introduced in RTSC and REC. However, they are more "accounting" in nature and are unable to fully implement the management of energy processes in order to increase energy efficiency and reduce costs. The proposed method includes a model and methods that allow determining the boundaries of the beginning and completion of bifurcation processes, implementing forecasting of electrical consumption of RTSC and REC facilities based on accounting for additional resources and implementing regime rationing of electrical consumption of facilities without disrupting the technological process. The application of this method can be carried out within the framework of dynamic modeling of the electrical consumption process, the study of bifurcation processes, as well as a theoretical basis for creating service software for digital electrical consumption management platforms for the regional transport and network complex, regional electrical grid complex and regional port complexes.

Evolution of Thermophilic Microbial Communities from a Deep-Sea Hydrothermal Chimney under Electrolithoautotrophic Conditions with Nitrate

Recent studies have shown the presence of an abiotic electrical current across the walls of deep-sea hydrothermal chimneys, allowing the growth of electroautotrophic microbial communities. To understand the role of the different phylogenetic groups and metabolisms involved, this study focused on electrotrophic enrichment with nitrate as electron acceptor. The biofilm density, community composition, production of organic compounds, and electrical consumption were monitored by FISH confocal microscopy, qPCR, metabarcoding, NMR, and potentiostat measurements. A statistical analysis by PCA showed the correlation between the different parameters (qPCR, organic compounds, and electron acceptors) in three distinct temporal phases. In our conditions, the Archaeoglobales have been shown to play a key role in the development of the community as the first colonizers on the cathode and the first producers of organic compounds, which are then used as an organic source by heterotrophs. Finally, through subcultures of the community, we showed the development of a greater biodiversity over time. This observed phenomenon could explain the biodiversity development in hydrothermal contexts, where energy sources are transient and unstable.

ENERGY SAVINGS IN AUXILIARY VENTILATION SYSTEMS OF UNDERGROUND MINES

Energy is a basic need for industries around the world. In recent years, electrical power costs have risen considerably and this rise is likely to continue in the future. Meanwhile, the increasing cost of ventilating mines safely and efficiently is of vital importance. Ventilation on demand has the potential to optimize electrical consumption while maintaining the safety of mines. This paper investigates the energy efficiency enhancement through ventilation on demand in underground mines by installing variable speed drives on the auxiliary mine ventilation fans to provide variable airflow control. Variable speed drives are cost effective and manageable and require low maintenance. It has been estimated that a total electrical energy saving of 324,300 kW, or 53%, can be achieved in 1 year by using variable speed drives. Therefore, it is possible to reduce CO2 emissions by 155.6 tons per year with a simple payback period of 5 months 220 days.

Enhancement of refrigeration system performance by refrigerant capillary injection in evaporator

In this paper, the enhancement of refrigeration system performance by refrigerant capillary injection in evaporator was experimentally investigated. An experimental bench was developed in order to compare the performance of a refrigeration system operating in conventional throttling and capillary injection modes. The temperature distribution in the evaporator and the compressor electrical consumption were determined, showing that in the capillary injection mode, the refrigeration system was more stable, its time to reach the steady state was reduced by 62.5 % and its COP was enhanced by 9 %.