Conditioning System Research Articles

Global early replication disrupts gene expression and chromatin conformation in a single cell cycle

BackgroundThe early embryonic divisions of many organisms, including fish, flies, and frogs, are characterized by a very rapid S-phase caused by high rates of replication initiation. In somatic cells, S-phase is much longer due to both a reduction in the total number of initiation events and the imposition of a temporal order of origin activation. The physiological importance of changes in the rate and timing of replication initiation in S-phase remains unclear.ResultsHere we assess the importance of the temporal control of replication initiation using a conditional system in budding yeast to drive the early replication of the majority of origins in a single cell cycle. We show that global early replication disrupts the expression of over a quarter of all genes. By deleting individual origins, we show that delaying replication is sufficient to restore normal gene expression, directly implicating origin firing control in this regulation. Global early replication disrupts nucleosome positioning and transcription factor binding during S-phase, suggesting that the rate of S-phase is important to regulate the chromatin landscape.ConclusionsTogether, these data provide new insight into the role of the temporal control of origin firing during S-phase for coordinating replication, gene expression, and chromatin establishment as occurs in the early embryo.

Multi-Objective Optimal Design of SPMSM for Electric Compressor Using Analytical Method and NSGA-II Algorithm

In contrast to internal combustion engine vehicles, electric vehicles (EVs) obtain the power required for the compressor of air conditioning system from an electric source. Therefore, an optimal design for electric motor, the main component of an electric compressor, is essential for improving EV mileage. A multi-objective optimal design is required because the characteristics of the motor are in a trade-off relationship with each other. When the finite element method (FEM) is used, multi-objective optimal designs for the motor take a significant amount of time because of the diversity analyses required for the optimal-model search. To solve this problem, in this study, a multi-objective optimal design method of an SPMSM for an EVs air conditioner system compressor was proposed and applied using the NSGA-II and an analytical method. The validity of the proposed method was confirmed by comparing the characteristics of the optimal design model with those of the initially designed model.

Performance Analysis of Universal Power Quality Conditioner Systems Based on Seven-level NPC Inverter Using PD-SPWM with Fuzzy Control Scheme

This paper presents novel Unified Power Quality Conditioner (UPQC) system based on seven-level Neutral Point Clamped (NPC) inverter using combined PD-SPWM and fuzzy control scheme. The proposed UPQC is adopted to mitigate source current harmonics and compensate all voltage disturbances simultaneously. It is designed by the combination of series and shunt Active Filters (AFs) connected by a common DC link capacitor. The DC voltage at common DC bus is maintained constant using proportional integral voltage controller. The Synchronous Reference Frame (SRF) method is used to get the shunt APF reference signals and the power reactive theory (P-Q theory) for the series APF. Conventional control schemes require complex calculations, the use of intelligent systems help to reduce the control system size and the operation complexity. The shunt and series Active Power Filter (APF) reference signals derived from the control algorithm are injected in Fuzzy intelligent controllers to generate switching signals. The functionality of proposed UPQC system and its control system is evaluated using Matlab-Simulink software and SimPowerSystem Toolbox under various operation conditions in cases of most common power quality problems such as voltage sag, voltage swell, current harmonic compensation of nonlinear loads and unbalanced load. The simulation results show UPQC performances to improve the power quality in steady and transient conditions operation at the point of common coupling on power distribution under unbalanced and distorted voltage conditions.

A numerical approach for preventing the dispersion of infectious disease in a meeting room

Airborne transmission of respiratory aerosols carrying infectious viruses has generated many concerns about cross-contamination risks, particularly in indoor environments. ANSYS Fluent software has been used to investigate the dispersion of the viral particles generated during a coughing event and their transport dynamics inside a safe social-distance meeting room. Computational fluid dynamics based on coupled Eulerian–Lagrangian techniques are used to explore the characteristics of the airflow field in the domain. The main objective of this study is to investigate the effects of the window opening frequency, exhaust layouts, and the location of the air conditioner systems on the dispersion of the particles. The results show that reducing the output capacity by raising the concentration of suspended particles and increasing their traveled distance caused a growth in the individuals' exposure to contaminants. Moreover, decreasing the distance between the ventilation systems installed location and the ceiling can drop the fraction of the suspended particles by over 35%, and the number of individuals who are subjected to becoming infected by viral particles drops from 6 to 2. As well, the results demonstrated when the direction of input airflow and generated particles were the same, the fraction of suspended particles of 4.125%, whereas if the inputs were shifted to the opposite direction of particle injection, the fraction of particles in fluid increased by 5.000%.

Unified Power Quality Conditioner Performance based on Multi-level Inverter Topologies using Intelligent Controllers

This paper presents unified power quality conditioner (UPQC) system based on three-level neutral point clamped (NPC) using Fuzzy and ANN controllers. The proposed UPQC is able to mitigate source current harmonics and compensate all voltage disturbances. It is designed by the integration of series and shunt active filters (AFs) sharing a common DC bus capacitor. The DC voltage is maintained constant using proportional integral voltage controller. The synchronous reference frame (SRF) theory is used to get the reference signals for the shunt APF and the power reactive theory (P-Q theory) for the series APF.Conventional control schemes require complex calculations, the use of intelligent systems help to reduce the control system size and the operation complexity. The shunt and series active power filter (APF) reference signals derived from the control algorithm are injected in Fuzzy and Ann intelligent controllers to generate switching signals. The performances of the proposed UPQC system are evaluated using Matlab-Simulink software and SimPowerSystem Toolbox under various operation conditions. The simulation results show the performance of the proposed UPQC based on intelligent controllers to improve the power quality in steady and transient conditions operation.

Energy-efficient air conditioning system using a three-fluid heat exchanger for simultaneous temperature and humidity control

Room air conditioners are unable to simultaneously control the temperature and humidity of the air supply. Although temperature-regulating dehumidifiers can simultaneously control the temperature and humidity, they have complex refrigerant pipelines, and the heat exchanger exhibits air resistance when the reheat demand is low. This study proposes an air conditioning system for simultaneous temperature and humidity control, using a three-fluid heat exchanger. The supply air temperature is adjusted by changing the air volume ratio and cooling water flow rate through the three-fluid heat exchanger, which is used as the condenser. Free cooling can be realized by supplying low-temperature cooling water to treat the return air. Numerical models were built to simulate the performance of the devices in the system, and were validated by experimental results. The temperature-regulating performance and energy consumption under different conditions were numerically calculated using a case-studied air-conditioned room in Beijing. The results are summarized as follows: 1. The proposed strategy can regulate the supply air temperature over a wide range of temperatures. 2. Compared with those of the temperature-regulating dehumidifier system, the compressor and fan energy consumption of the proposed system are reduced by 19.1% and 15.5%, respectively, with a total energy-saving rate of 15.8% in the cooling season. 3. Compared with those of the room air conditioner system, the compressor energy consumption of the proposed system is reduced by 11.5%, and the energy-saving rate of the entire system is 6.3%. The initial investment of the proposed system does not increase significantly compared with conventional systems, and the refrigerant pipeline and valves can be simplified, resulting in acceptable economic performance for the proposed system.

Mitigation of the biosafety risks of SARS-CoV-2 at BSL-3 laboratories

Aim: The aim of this study is to reduce the biosafety risks of laboratory exhaust air due to SARS-CoV-2 at a biosafety level-3 laboratory used for vaccine development against COVID-19 pandemic. Materials and Methods: In this study, the infrastructure and the organisation of the containment laboratory, which aimed to be used to struggle with pandemic, was used for risk assessment. Assessment of the laboratory exhaust air procedure as a component of the heating-ventilation-air conditioning system, which is significant for high-level biosafety laboratories, was conducted through a risk assessment matrix.

Multi‐functional control strategy for power quality improvement of three‐phase grid using solar PV fed unified power quality conditioner

This article presents a generalised integrator with a band-pass filter frequency locked loop (GI-BPF-FLL) control algorithm for the solar photovoltaic (SPV)-integrated unified power quality conditioner (SPVUPQC) system. This control algorithm extracts fundamental components (FC) of the distorted and deformed input signals, and it has the competence of eliminating DC-offset. The key objective is to decrease the number of sensors used in the control algorithm of the SPVUPQC system while enabling the power quality enhancement features in the distribution grid. The effectiveness of the presented GI-BPF-FLL control algorithm and its performance comparison with the conventional control algorithm are discussed in both the time domain as well as frequency domain analysis. The SPVUPQC system consisting of a distribution static compensator (DSTATCOM) and a dynamic voltage restorer (DVR), to compensate simultaneously both the voltage distortions, sag/swell etc. as well as current harmonics, reactive power and load currents unbalances etc. The model of the SPVUPQC system is developed in the MATLAB/Simulink environment, and its results are presented to demonstrate its capabilities. The system's validation is also done on the hardware prototype, and it performs effectively for the voltage and current power quality enhancement simultaneously. The load side voltages magnitudes, grid side voltages and the grid currents total harmonic distortions are found within the boundaries specified in the IEEE standard 1159 and the IEEE standard 519.

Cooling performance analysis of nanofluid assisted novel photovoltaic thermoelectric air conditioner for energy efficient buildings

• Novel radiator coupled nanofluid based thermoelectric air conditioning (NTEAC) system was developed. • Performance of the PV powered NTEAC system is analysed in a real time building of 25.6 m 3 size. • NTEAC system reduced the temperature of the test room below 22 °C with 6 A current. • Significant savings in power consumption and carbon emissions has been fortified. Carbon emissions and excessive power usage are addressed by applying thermoelectric cooling, which benefits from its ability to be portable, economical, and reliable. However, a conventional thermoelectric air conditioner's coefficient of performance (COP) is much less due to the sustained heat generated on the thermoelectric module's hot side. This work presents a novel idea of utilizing a nanofluid cooled radiator as an external cooling jacket around the thermoelectric module's hot side to enhance the heat transfer rate of thermoelectric air conditioners. In this research, the performance of a newly designed thermoelectric air conditioner (TEAC) powered by photovoltaic systems (PV) installed in a residential building is analyzed using nanofluid as a coolant. Furthermore, by supplying different input currents (2-6A), the cooling characteristics and performance of the newly designed nanofluid assisted thermoelectric air conditioner (NTEAC) system were experimentally studied in a test room of 25.6 m 3 volume in Malaysia's tropical climate. The system's best performance was at 6A, with a maximum temperature drop of 4.9 °C, a cooling capacity of 571 W, and a coefficient of performance of 1.27. In addition, the NTEAC system showed an energy saving of 67% and CO 2 emission mitigation of 76% when compared with a conventional split air conditioner. Thus, an alternative to the traditional air conditioning system was developed from this research, which is Freon free. This system is expected to consume less energy and emit less CO 2 for the tropical climatic conditions.

A novel active building envelope with reversed heat flow control through coupled solar photovoltaic-thermoelectric-battery systems

Heat transmit between ambient and indoor space passively through building envelope. This heat flow intensity can be reduced by using insulations and eliminated by conventional air conditioner, which causes huge amount of energy. In this study, a new concept is proposed for a new active building envelope system that can realize heat gain/loss control and in some senses the conventional air conditioner system could be saved, because it is shown that the building envelope itself could be an air conditioner. It should be specially noted that, we can set parameter Qw in this system to determine how much extra thermal energy you want from the new building envelope. It is based on the combination of photovoltaic (PV), thermoelectric modules (TEM), energy storage and control algorithms. Five types of systems, namely PV + TE (S1), Grid + TE (S2), PV + Grid + TE (S3), PV + Battery + TE (S4) and PV + Grid + Battery + TE (S5) are studied. It is found that in all the five systems, there is a typical optimum setting of thermal load for each one of them with minimum annual power consumption.

On Hourly Forecasting Heating Energy Consumption of HVAC with Recurrent Neural Networks

Optimizing the heating, ventilation, and air conditioning (HVAC) system to minimize district heating usage in large groups of managed buildings is of the utmost important, and it requires a machine learning (ML) model to predict the energy consumption. An industrial use case to reach large building groups is restricted to using normal operational data in the modeling, and this is one reason for the low utilization of ML in HVAC optimization. We present a methodology to select the best-fitting ML model on the basis of both Bayesian optimization of black-box models for defining hyperparameters and a fivefold cross-validation for the assessment of each model’s predictive performance. The methodology was tested in one case study using normal operational data, and the model was applied to analyze the energy savings in two different practical scenarios. The software for the modeling is published on GitHub. The results were promising in terms of predicting the energy consumption, and one of the scenarios also showed energy saving potential. According to our research, the GitHub software for the modeling is a good candidate for predicting the energy consumption in large building groups, but further research is needed to explore its scalability for several buildings.

Investigation of Working Fluid Performance through a Centrifugal Compression System

Commonly, researchers have investigated many factors that impact the performance of air conditioning and refrigeration systems, such as varied cooling configurations, operating conditions and optimization of specific system components. Although there is an abundance of research detailing the importance of working fluid selection, very few studies focus on how the working fluid selection influences the performance of the individual components of the system, such as the compressor. In this paper, the performances of a selection of working fluids are compared through a centrifugal compressor using CFD. The working fluids considered are R1234ze, R1234yf, R152a, R444a, R445a, R290 and R600a and were selected due to suitability as replacements to R134a. Each fluid, including R134a, was compared based on the performance of a centrifugal compressor with fixed inlet conditions across two operational speeds. The results indicate that R1234ze and R1234yf demonstrated the best performance as replacements to R134a, achieving the highest overall pressure ratios. Additionally, R1234ze also displayed similar power required through the compressor to R134a indicating greater suitability as a drop-in replacement. The working fluids R444a and R445a both displayed performance similar to that of R134a across both operational speeds, indicating reasonable suitability as a replacement to R134a. Alternatively, R152a, R290 and R600a displayed reduced performance compared to R134a and subsequently, are not suitable replacements based on the compression system considered in this study. As well as considering the observed differences in the performance from the selected working fluids, the implications of the results for industrial applications are also considered, along with avenues for further work.

GEODETIC SUPPLY FOR THE CONSTRUCTION OF ENGINEERING STRUCTURES

The construction of engineering structures when transferring the project to the area is impossible without geodetic work. The composition and sequence of engineering and geodetic works depend on the features of the design and construction of facilities and the type of structure. The purpose of the article is to consider geodetic works in the construction of engineering structures. The issues of performing engineering and geodetic works during the construction of structural elements of the bridge are considered. During the construction process, it is necessary to ensure full compliance with the design documentation and high accuracy of work performance. These requirements can be achieved by using high-precision geodetic works with constant monitoring of the installation work. At all stages of the bridge construction, geodetic works accompany the transfer to the terrain of the bridge axis, the resistance axis, perform a detailed breakdown during the construction of resistances and the installation of purlins. Also, the construction of individual parts of the building is constantly monitored, the dimensions and shape of the mounting elements are checked. When building large structures, it is necessary to have information about the points of the geodetic base of the bridge crossing, an extract from the catalog of coordinates and elevations of the geodetic base. The breakdown is carried out by tying to the points of the geodetic reference network, which has coordinates in the absolute or conditional system. Modern construction requires the use of new technologies and methods for performing geodetic work related to the introduction of electronic devices and programs for automated information processing into geodetic practice. Currently, a large number of geodetic instruments and new technologies in geodesy have been created, which differ from traditional ones. To carry out survey work, geodetic instruments, such as electronic total station and levels, were used. The electronic total station measures distances, angles and processes data directly in the process of field work, has an internal memory where it can store all the data obtained as a result of measurements. The digital level has a device for automatic registration of measurements along the rail and a processor for subsequent processing of all leveling results. During measurements, the device measures the distance to the rail and the elevation between points. This eliminates two main types of errors: observation errors when taking a reading and error in distance measurements. During the construction of supports, a temporary rapper is installed on each of them, which is tied to permanent rappers by leveling moves. The removal of marks on the supports is carried out by methods of geometric or trigonometric leveling. The coordinates of the rappers were received and entered into the local plan. Marks for serifs of the device with a retroreflective effect were pasted on the bridge supports. The data of coordinates and heights were entered into the total station memory. Geodetic work carried out during the construction of the span structure ensures the accuracy of its assembly in accordance with the project. After the installation is completed, the assembly results and deviations from the project are monitored. The construction of structural elements of engineering structures must comply with building codes and geometric parameters of the facility design.

Trip energy consumption estimation for electric buses

This study aims to develop a trip energy consumption (TEC) estimation model for the electric bus (EB) fleet planning, operation, and life-cycle assessment. Leveraging the vast variations of temperature in Jilin Province, China, real-world data of 31 ​EBs operating in 14 months were collected with temperatures fluctuating from −27.0 ​to 35.0 ​°C. TEC of an EB was divided into two parts, which are the energy required by the traction and battery thermal management system, and the energy required by the air conditioner (AC) system operation, respectively. The former was regressed by a logarithmic linear model with ambient temperature, curb weight, travel distance, and trip travel time as contributing factors. The optimum working temperature and regression parameters were obtained by combining Fibonacci and Weighted Least Square. The latter was estimated by the operation time of the AC system in cooling mode or heating mode. Model evaluation and sensitivity analysis were conducted. The results show that: (i) the mean absolute percentage error (MAPE) of the proposed model is 12.108%; (ii) the estimation accuracy of the model has a probability of 99.7814% meeting the requirements of EB fleet scheduling; (iii) the MAPE has a 1.746% reduction if considering passengers’ boarding and alighting.

Development of a Solar-Powered Car Ventilation System with Wireless Monitoring

The heat effect induced by hot weather causes car cabins to absorb heat from the surrounding area, making the temperature inside the compartment higher than the temperature outside. The excessive heat that gets trapped in closed cabins makes drivers and passengers uncomfortable when they enter their cars. This situation can be resolved by increasing air conditioning power while the engine is running, and this condition would increase the heat load of the air conditioner system. To this end, the present study describes the development of a solar- powered car ventilation system that relies on the Internet of things (IoT). The proposed solar- powered car ventilation system consists of a temperature sensor (DHT22) that detects the temperature inside the car cabin. Further, NodeMCU ESP32 has been used as a microcontroller to control the system. Temperature, fans, windows, and rainfall conditions were monitored via wireless connections using the Blynk application. The results show that the proposed ventilation system can reduce car cabin temperature and that its temperature readings can be monitored through the user’s mobile device. Furthermore, because the system operates on solar energy, it is environmentally friendly.

Neuropeptide Neuromedin B does not alter body weight and glucose homeostasis nor does it act as an insulin-releasing peptide

Neuromedin B (NMB) is a member of the neuromedin family of neuropeptides with a high level of region-specific expression in the brain. Several GWAS studies on non-obese and obese patients suggested that polymorphisms in NMB predispose to obesity by affecting appetite control and feeding preference. Furthermore, several studies proposed that NMB can act as an insulin releasing peptide. Since the functional study has never been done, the in vivo role of NMB as modulator of weight gain or glucose metabolism remains unclear. Here, we generated Nmb conditional mice and nervous system deficient NmB mice. We then performed olfactory and food preference analysis, as well as metabolic analysis under standard and high fat diet. Additionally, in direct islet studies we evaluated the role of NMB on basal and glucose-stimulated insulin secretion in mouse and humans.

2. Legislation of SAKIGAKE Designation System and Conditional Early Approval System of New Drug

2. Legislation of SAKIGAKE Designation System and Conditional Early Approval System of New Drug

The cost-effectiveness of standalone HEPA filtration units for the prevention of airborne SARS CoV-2 transmission

ObjectiveAirborne infection from aerosolized SARS-CoV-2 poses an economic challenge for businesses without existing heating, ventilation, and air conditioning (HVAC) systems. The Environmental Protection Agency notes that standalone units may be used in areas without existing HVAC systems, but the cost and effectiveness of standalone units has not been evaluated.Study designCost-effectiveness analysis with Monte Carlo simulation and aerosol transmission modeling.MethodsWe built a probabilistic decision-analytic model in a Monte Carlo simulation that examines aerosol transmission of SARS-CoV-2 in an indoor space. As a base case study, we built a model that simulated a poorly ventilated indoor 1000 square foot restaurant and the range of Covid-19 prevalence of actively infectious cases (best-case: 0.1%, base-case: 2%, and worst-case: 3%) and vaccination rates (best-case: 90%, base-case: 70%, and worst-case: 0%) in New York City. We evaluated the cost-effectiveness of improving ventilation rate to 12 air changes per hour (ACH), the equivalent of hospital-grade filtration systems used in emergency departments. We also provide a customizable online tool that allows the user to change model parameters.ResultsAll 3 scenarios resulted in a net cost-savings and infections averted. For the base-case scenario, improving ventilation to 12 ACH was associated with 54 [95% Credible Interval (CrI): 29–86] aerosol infections averted over 1 year, producing an estimated cost savings of $152,701 (95% CrI: $80,663, $249,501) and 1.35 (95% CrI: 0.72, 2.24) quality-adjusted life years (QALYs) gained.ConclusionsIt is cost-effective to improve indoor ventilation in small businesses in older buildings that lack HVAC systems during the pandemic.

Secure Wireless Networks Based on Fuzzy Logic for Smart HVAC Systems in Small-Scale Industries

The traditional heating, ventilation, and air conditioning (HVAC) system depends on wired mechanical thermostats and regulators deployed at various points in the industrial environment for temperature monitoring. Due to ineffective dynamic changes according to the environment, the traditional HVAC system consumes more electrical energy. Next-generation wireless network (NGWN) systems play a vital role in improving the overall efficiency of the system by continuous monitoring and analysis. A small-scale industry using HVAC systems needs an active smart energy saver technique for maintaining an economical budget. This work uses MATLAB software to simulate and analyze the utilization of fuzzy-based NGWN to reduce the energy consumption requirements of small-scale manufacturing. In the model, a fuzzy rule is designed and applied to a small-scale enterprise divided into five sectors, one of which is temperature sensitive, with the goal of lowering the energy bill. The model employs fuzzy rules to enhance the NGWN, which minimizes the energy usage cost by 30% as compared with the traditional existing HVAC systems.

Development and Control of a Photovoltaic Fed Flywheel Energy Storage System for Power Conditioning

The concept of newer energy storage and power conditioning using suitable controllers in a solar photovoltaic fed Flywheel Energy Storage System (FESS) is presented in this work. The power from a solar photovoltaic arrangement is harvested using a Sinusoidal Pulse Width Modulated (SPWM) DC-DC converter to provide a controlled, efficient, and regulated output to drive the FESS. The FESS is designed with the BLDC motor as prime mover that drives a flywheel of cylindrical mass of suitable material and radius. The alternator connected in the same shaft of the prime mover and flywheel, powers an electrical load of 1kW. The dynamic stability of the system is taken care by the flywheel, while reliability is ensured using a well-designed controller unit. The solar PV arrangement with its controller was simulated using MATLAB, the flywheel stress was found using ANSYS. The entire FESS was simulated and based on the simulation results. A working model was fabricated, installed, and tested for the required operation. Test results were compared. Graphical representations are given to substantiate the working of the flywheel energy storage system.