Mode Of Operation Research Articles

Rapid evaporative ionization mass spectrometry: A survey through 15 years of applications.

Rapid evaporative ionization mass spectrometry (REIMS) is a relatively recent MS technique explored in many application fields, demonstrating high versatility in the detection of a wide range of chemicals, from small molecules (phenols, amino acids, di- and tripeptides, organic acids, and sugars) to larger biomolecules, that is, phospholipids and triacylglycerols. Different sampling devices were used depending on the analyzed matrix (liquid or solid), resulting in distinct performances in terms of automation, reproducibility, and sensitivity. The absence of laborious and time-consuming sample preparation procedures and chromatographic separations was highlighted as a major advantage compared to chromatographic methods. REIMS was successfully used to achieve a comprehensive sample profiling according to a metabolomics untargeted analysis. Moreover, when a multitude of samples were available, the combination with chemometrics allowed rapid sample differentiation and the identification of discriminant features. The present review aims to provide a survey of literature reports based on the use of such analytical technology, highlighting its mode of operation in different application areas, ranging from clinical research, mostly focused on cancer diagnosis for the accurate identification of tumor margins, to the agri-food sector aiming at the safeguard of food quality and security.

Green Energy Solution for Grid Integrated Solar PV System for Water Storage Towers

In India, water storage towers are present almost everywhere, especially across small towns to rural areas. The storage tanks either utilize diesel powered or utility grid fed induction motor (IM) water pumps. The large spaces available with water storage towers can be utilized to plant solar PV panel for large storage towers water pumping operation, hence, making a switch from diesel or grid run storage towers to solar operated storage towers. This paper presents a robust control of grid integrated solar PV-based water pump system with efficient and smooth transition between standalone and grid interfaced modes. A smart DC link voltage control is presented for distributed generation system (DGS), which provides full control on DC link voltage for both modes of operation at all dynamic load conditions. An enhanced phase-locked loop (EPLL) control is utilized for grid source converter (GSC) in grid control operation, making it flexible to different grid scenarios and power quality. It works for harmonics suppression, load balancing and grid side converter control. An enhanced phase-locked loop (EPLL) is implemented for synchronization control algorithm, which provides an accurate estimation of voltage angle even during frequency ramps and exhibiting superior performance particularly in terms of robustness against DC offsets. The primary requirement for smooth operation of grid-tied solar PV system is effective power management between different sources. The issues of power management and power quality, are discussed in this work, and solutions are presented. The implemented control algorithms are tested successfully for dynamic solar insolation, varying load conditions, unbalance in load, sudden grid outage condition. The system appropriateness is validated by experimental results.

Assessment of antimicrobial and anti-biofilm activities of lemongrass and bay leaf extracts on microorganisms from fermented cereal-based porridges in northern Benin

Lemongrass (Cymbopogon citratus) and bay leaf (Laurus nobilis) are condiments in food processing. This study aimed to assess the antimicrobial and anti-biofilm activities of lemongrass and bay leaf extract on the microorganisms isolated from cereal-based fermented porridges produced in northern Benin. The phytochemical components of lemongrass and bay leaf extracts were analyzed qualitatively using two solvents: water and alcohol. The antimicrobial activity of the extracts was tested using the solid media diffusion method, and the minimum concentration was determined using the microdilution method. The extracts were also evaluated for their ability to inhibit biofilm formation using qualitative assays. The two plants have different phytochemical profiles. Tannins, flavonoids, mucilage, and alkaloids were detected in both plants. Cyanogenic derivatives, O-heterosides, and genin-reduced O-heterosides were absent. L. nobilis contained anthocyanins, quinone derivatives, saponosides, reducing compounds, and free anthracenes, absent in C. citratus. The inhibition diameters ranged from 4.4 to 26.3, depending on the strains and extracts, and varied significantly. The MICs for Escherichia coli ranged from 4.5 mg/ml to 7 mg/ml, staphylococci from 3.75 mg/ml to 10 mg/ml, and lactic bacteria from 2.5 mg/ml to 4.44 mg/ml. The CMB varied between 8.125 mg/ml and 14 mg/ml for E. coli, 7.5 mg/ml to 20 mg/ml for staphylococci, and 6 mg/ml to 10 mg/ml for lactic bacteria. It is worth noting that staphylococci are the most biofilm-producing strains (80%), followed by E. coli (60%), and lactic bacteria produce less biofilm (30%). The findings of this research confirm the presence of a wide range of biological activities, including antibacterial and anti-biofilm, in the aqueous and ethanolic extracts of these two aromatic plants. Further research is required to identify and isolate the active components responsible for their medicinal properties and ascertain their operation mode.

Thermal performance of pin fin heat sinks with phase change material for electronic devices thermal management

In the present paper, an experimental and numerical study is conducted to analyze various factors affecting the thermal performance of a heat sink with phase change material (HS-PCM). In order to maintain the chip below the limit temperature of 80 °C, ZDJN-35 with a phase change temperature of 37 ∼ 45 °C is selected as the energy storage material. Under different PCM filling volume fractions, heat fluxes, and operation modes, the study evaluates the thermal performance of the HS using chip temperature and the effective time extension coefficient. The volume fractions of PCM are 0 vol%, 30 vol%, 60 vol%, and 90 vol%. Under heat fluxes of 4000 ∼ 14000 W/m2, the results indicate that under continuous operation, the HS without PCM reaches the limit temperature within 18 min at heat flux of 8000 W/m2. In contrast, the time to reach the limit temperature for HS with 30 vol% PCM, 60 vol% PCM, and 90 vol% PCM extends by 12 min, 19 min, and 26 min, respectively. Compared to the HS without PCM, the peak temperatures reduce by 4.8 %, 10.5 %, and 12.8 % for the HS with 30 vol% PCM, 60 vol% PCM, and 90 vol% PCM under intermittent operation. Moreover, under intermittent operation, temperature fluctuations decrease by 27.3 %, 36.0 %, and 37.3 %, respectively. Finally, the numerical results show that the optimization of pin fin diameter is opposite for passive and active cooling modes, and a heat dissipation unit height of 25.5 mm is recommended.

Thermodynamic analysis of an evacuated tube solar collector system for industrial building application: A case study

In this study, a modified solar-Organic Rankine Cycle (ORC) assisted hydrogen production system for two different scenarios was experimentally investigated. In the study, evacuated tube solar collector (ETSC), ORC system, proton exchanger membrane electrolyzer (PEMe) unit is discussed with a holistic perspective. The presented work includes energy and exergy analysis of solar-ORC assisted hydrogen production. According to scenario 1 (S-1), only the case of hydrogen production from the installed system is considered. According to Scenario 2 (S-2), the both electrical energy and hydrogen production from the installed system is examined. As a result of the study, the energy efficiency in S-1 and S-2 operating modes was calculated as 9.553% and 16.02%, respectively. Additionally, the highest exergy efficiency for both scenarios was calculated as 6.129% in the S-2 scenario. Furthermore, hydrogen production amount of the S-1 and S-2 scenarios was calculated as 743.1 kg/annual and 371.5 kg/annual, respectively.

Can a dish be my PhD? A response to Bucher and Lee

As culinary arts continue to evolve within the realms of higher education, an important question emerges: can a dish embody and communicate new, meaningful knowledge to the gastronomic community? The transition of culinary professionals into higher education, as discussed by Bucher & Lee (2023), outlines an academic and institutional landscape marked by intellectual challenges and epistemological tensions. Bucher and Lee's (2023) article reveals the friction that many culinary professionals face as they enter higher education, particularly the necessity to deviate from their innate, intuitive modes of understanding and operating. This commentary supports their perspective, advocating for a realm within higher education whereby the methodologies and methods deployed by chefs naturally within their everyday practice are not merely objects of academic scrutiny, but serve as sources of knowledge generation and dissemination within their own right.

Real-time and high-sensitive colorimetric sensor based on photonic crystal for amniotic fluid identification

In this study, we proposed a pH-responsive photonic crystal hydrogel sensor (PCHs) to conveniently and accurately recognize the amniotic fluid from urine of parturient women, which was constituted by three-dimensional polymethyl acrylamide (PMMA) array and optimized hydrogel. PMMA array was self-assembled by 180 nm monodispersed nanoparticles with vertical sedimentation method. The functional hydrogel containing N-acryloyl phenylalanine (APA), acrylamide (AM) and N, N'-methylene bis(acrylamide) (BIS) as co-monomer and crosslinking agent respectively, was photo-polymerized by the precursor under 365 nm UV light. This hydrogel significantly shrank or swelled corresponding to the acidity and alkalinity of the aqueous solution, which resulted in both the reflection peak position (λmax) of the prepared sensor and its structural color changing with the pH value. The λmax of PCHs redshifted from 514 nm to 606 nm in 60 s while the pH value of testing solution increased from 4.5 to 8.0, which exactly covered the pH value of amniotic fluid and urine. Correspondingly, its structure color gradually changed from pale-green to red ensuring their naked-eye determination. Furthermore, an extremely high sensitivity as 26.3 nm/pH of Δλmax was obtained which was linearly related to pH value. The prepared sensor possessed steady accuracy and extraordinary sensitivity compared with the pH test strip which was generally used in amniorrhexis diagnosis nowadays besides the advantages of the low cost, simple operation, rapid response and visual detection mode. The reliability of this PCHs was further confirmed by the real sample detection which relative standard deviation was below 5.0 %, suggesting its potential clinical applications.

Process design and simulation of methyl isobutyl ketone (MIBK) dehydration by batch distillation: A study on unit configuration and operational policies

Heteroazeotropic batch distillation of methyl isobutyl ketone-water binary mixture is investigated, seeking a reliable operation for dehydration of methyl isobutyl ketone (MIBK). The dynamic batch distillation module (BatchSep) of the commercial package Aspen Plus V.12.1® is applied for simulations. An initially fed unit at atmospheric pressure is simulated from the heating-up step until it reaches the desired MIBK purity of 99.8 wt%. Three configurations, namely conventional batch distillation unit (Mode I), batch distillation unit with decanter (Mode II), and a simple distillation unit (Mode III), are compared in a wide range of operating conditions. The effects of condenser temperature and the number of theoretical stages are also examined. According to the results, applying a decanter (Mode II) with a return fraction of over 0.75 for the MIBK-rich phase and below 0.4 for the aqueous phase provides higher MIBK recovery than the maximum achievable value in a conventional unit (Mode I), with almost no increase in process time. A perfect decanter offers an almost complete MIBK recovery, which is about 5% over the maximum value by conventional units (Mode I). Moreover, cutting the reflux (Mode III) offers the fastest way to the desired product but provides the lowest MIBK recovery value. The aqueous phase return fraction does not significantly impact MIBK recovery, but if it exceeds 0.5, it remarkably affects the process time/energy cost. When maximum MIBK recovery rate/minimum energy cost is desired, applying a decanter (Mode II) with a return fraction above 0.5 for the MIBK-rich phase and below 0.55 for the aqueous phase yields a higher production rate and a lower energy cost per unit quantity of product compared to the best achievable values for a conventional unit (Mode I). A perfect decanter improvesproductionrateandenergyefficiencyby8 %overthe best case in a conventionalunit (ModeI). Also, operation without reflux (Mode III) is preferred over a conventional operation (Mode I) with a total return fraction over 0.7 due to its superior energy efficiency and production rate.

Insights into shock velocity variation in double-diaphragm shock tubes

A comprehensive understanding of shock formation and propagation in shock tubes is crucial for their diverse applications. The shock velocity in single-diaphragm shock tubes, characterized by initial acceleration and subsequent attenuation due to viscous effects, has been extensively investigated. However, limited studies exist on the double-diaphragm mode of operation. In this study, shock tube experiments were conducted using helium at pressures of 10–60 bar as driver gas and argon at pressures of 100–600 Torr as driven gas. The shock velocity profiles in the double-diaphragm mode show a sequence of acceleration and deceleration stages of the shock front, strongly influenced by the driver-to-driven pressure ratios (P41) and the pressure in the intermediate section (Pmid). Particularly, at high values of P41, peak shock velocities can exceed those measured near the end wall by about 12%. Large axial temperature gradients arise in the driven gas due to the accelerating and decelerating shock. Selecting appropriate diaphragms to maintain the intermediate section's pressure close to the value of the driver pressure can reduce peak shock velocities and post-shock temperatures. An in-house one-dimensional (1D) weighted essentially non-oscillatory scheme-based code was utilized to analyze wave interactions in the shock formation region, revealing that the post-shock gas behind the secondary diaphragm and inhibition of the primary diaphragm's opening and subsequent reopening can lead to unique shock profiles in double-diaphragm shock tubes. These insights deepen our understanding of wave propagation in shock tubes and suggest ways to mitigate undesirable effects in double-diaphragm shock tubes.

Optimizing mixing efficiency of anaerobic digesters with high total solids concentrations using validated CFD simulations

In this article, viscosity dependent mixing in anaerobic digestion (AD) towers is analysed using finite volume based computational fluid dynamics (CFD) simulations validated with ultrasound particle image velocimetry (uPIV). The study focuses on improving mixing characteristics for enhanced biogas production resulting from increased organic loading. Mixing of fluids with viscosity ranges found in real-life AD is investigated using the multiple reference frame (MRF) method. The aim is to increase the energetic efficiency of AD by reducing the energy demand required for sufficient mixing such that microorganisms and organic substrates are homogeneously distributed. The distinguishing feature of this work is the implementation of less power-consuming helical ribbon stirring devices (HRSD) for enhanced mixing in different reactor designs. It is demonstrated that HRSD become progressively effective for increasing total solids concentrations (% TS) ranging from 2.5 % TS to 12.1 % TS, particularly in cylindrical reactors. In comparison with conventional propeller-based mixers, innovative HRSD operation reduces dead volume (DV) by up to 22 %. Additionally, HRSD cause less shear forces and require less power due to lower rotational speed. The most energy-efficient mode of operation reduces the power demand by 9.29 % at 12 rpm, while still providing decreased DV of 13.38 % for the most viscous fluid investigated. The outcome is a more efficient and cost-effective mixing approach, which holds strong potential for mixing applications involving highly viscous fluids.

Economic and low-carbon planning for interconnected integrated energy systems considering emerging technologies and future development trends

The integrated energy system facilitates the synergistic and efficient utilization of diverse energy. Establishing interconnected regional energy internets by linking multiple integrated energy systems enables the realization of cross-sector, cross-temporal, and cross-subject energy coupling, consequently enhancing economic benefits, driving profound decarbonization, and bolstering energy resilience. This study develops a multi-agent planning model grounded in an electricity-heat-hydrogen sharing framework, collaboratively optimizing capacity configurations and energy scheduling strategies across various integrated energy systems containing emerging technologies. Furthermore, this study integrates the trading volume and prices of various energy sources to distinguish the energy sharing contribution of each participant, then combines with the Nash bargaining game, forming a fair cooperative benefit allocation incentive mechanism. The proposed model is adeptly solved using the alternating directions method of multipliers, ensuring the protection of participants’ private information. To reflect seasonal characteristics of energy supply and demand, this study uses the daily data of three integrated energy systems across four seasons to simulate. The research results reveal an annual cost saving of 233.73 thousand RMB and a reduction of 290.85 tCO2. Additionally, the impact of variations in electricity operation modes, uncertainties, and emerging technical advances are evaluated to further validate the sustainability of the multi-energy trading mechanism.

Comparison study of three universal methods for the recovery and purification of valuable heavy metals from electroplating sludge

The large amount of heavy metals from waste electroplating sludge has great recovery and treatment value, which is of great significance for environmental protection, resource recycling and sustainable development. In actual process, metals were relatively easy to be extracted from sludge, but the separation process was more complex. In this study, three universal methods for extracting low-grade and complex heavy metals from electroplating sludge (actual solid waste sample from Zhejiang Province, China) in terms of Selective ammonia treatment process (SAP), efficient acid treatment process (EAP) and roasting-acid treatment process (RAP) were investigated. In comparison, EAP was more advanced in extracting heavy metals from actual samples than SAP and RAP. It was noticed, by optimizing the separation and purification process, when the acid concentration was 5 % and the liquid–solid ratio was 10:1 with the assistance of effective extractants of Lix984N and P507, the purity and recovery rates for both copper and zinc products could reach to over 90 %, meanwhile, more than 80 % recovery rates of nickel products could be obtained. And compared with some existing related studies, the research process has the advantages of simpler operation mode and better separation effect, which offers the valuable insights into efficient separation and recovery of heavy metal resources from electroplating sludge. The methodology employed in this work can be easily applied to other solid/hazardous waste extraction processes.

A Distributed Learning-Based Economic Dispatch Approach of Microgrids Considering Operational Mode Switch

A Distributed Learning-Based Economic Dispatch Approach of Microgrids Considering Operational Mode Switch

Моделирование динамики связанных гиротронов методом крупных частиц

The problem of mutual synchronization of two coupled gyrotrons in the 170 GHz waveband was simulated using the particle-in-cells method. To reduce the calculation time, an approach based on replacing the asymmetric operating mode with an equivalent axisymmetric mode was used. As a result, the dimension of the problem is reduced, and instead of three-dimensional modeling, 2.5-dimensional modeling can be used. The limiting case is considered when the lowest axisymmetric mode of the circular waveguide TE01 is chosen as the equivalent mode. The results obtained are demonstrated to be in good agreement with the traditional approach based on modeling of averaged equations.

Application of Wide‐Beam Transmission for Advanced Operations of SuperDARN Borealis Radars in Monostatic and Multistatic Modes

AbstractThe Super Dual Auroral Radar Network (SuperDARN) consists of more than 30 monostatic high‐frequency (HF, 8–20 MHz) radars to study dynamic processes in the ionosphere. SuperDARN provides maps of global‐scale ionospheric plasma drift circulation from the mid‐latitudes to the poles. The conventional SuperDARN radars consecutively scan through 16 beam directions with a lower limit of 1 minute to sample the entire field of view. In this work, we use the advanced capabilities of the recently developed Borealis digital SuperDARN radar system. Combining a wide transmission beam with multiple narrow reception beams allows us to sample all conventional beam directions simultaneously and to speed up scanning of the entire field‐of‐view by up to 16 times without noticeable deterioration of the data quality. The wide‐beam emission also enabled the implementation of multistatic operations, where ionospheric scatter signals from one radar are received by other radars with overlapping viewing areas. These novel operations required the development of a new model to determine the geographic location of the source of the multistatic radar echoes. Our preliminary studies showed that, in comparison with the conventional monostatic operations, the multistatic operations provide a significant increase in geographic coverage, in some cases nearly doubling it. The multistatic data also provide additional velocity vector components, increasing the likelihood of reconstructing full plasma drift velocity vectors. The developed operational modes can be readily implemented at other fully digital SuperDARN radars.

2D thermo-fluidynamic rotary model of an elastocaloric cooling device: The energy performances

Elastocaloric cooling has been considered a promising solid-state technology for cooling and heat pumping among the alternatives to vapor compression, at room temperature range. The technology is based on elastocaloric effect that is a thermophysical phenomenon occurring in materials like Shape Memory Alloys (SMA). The effect is detectable as a temperature change in the material if adiabatically subjected to a forcing field of mechanical nature. The latter provokes to the materials a stress that can derive from tension, compression, bending, torsion solicitations. As a result, the SMA experiments a structural phase change from austenite to martensite (coupled with heat addition) and temperature rise. Dually when the stress is removed, the SMA releases heat with a temperature decrease. In this paper the SUSSTAIN-EL rotary elastocaloric heat pump has been deeply investigated to test the energy performances while it works on open loop and closed loop, through a 2D numerical model based on the finite element method, for cooling and heating operation modes. The device employs a binary NiTi SMA as elastocaloric refrigerant and air as heat transfer medium. A wide set of working conditions has been considered like variable inlet mass flow rate, rotation frequency and thermal loads. The acquired results demonstrate that, both in open and closed loop, the prototype’s energy performances are promising and highly favourable for the intended macroscale collocation of the device.

Online Monitoring of Continuous Aqueous Two-Phase Flotation (ATPF) for the Development of an Autonomous Control Strategy

Aqueous two-phase flotation (ATPF) is a separation technique for isolating biological products such as enzymes from crude complex biosuspensions. The continuous operation mode of ATPF allows high throughput while maintaining a high separation efficiency. In this work, a laboratory plant for continuous ATPF with integrated online measurement technology is presented and ATPF experiments with the model enzyme phospholipase A2 are performed. Three electrical conductivity probes allow real time and spatially resolved characterization of phase mixing in the flotation tank caused by rising bubbles. UV/Vis spectroscopy is used to measure the enzyme concentration online at the top phase outlet. The equilibrium concentrations in the top and bottom phase are linearly dependent on the feed concentration, revealing a constant partition coefficient. The experimental results of this work provide the basis for the development of an autonomous feedback controller for the continuous ATPF process.

Enhancing the efficacy of humidifier-dehumidifier desalination in humid regions through the use of an absorption refrigeration cycle (an economic and experimental investigation)

This experimental study investigates the performance of a novel humidifier-dehumidifier (HDH) desalination system integrated with a vapor absorption refrigerator (VAR) and photovoltaic (PV) panels for humid regions. The effects of air mass flow rate (m˙a) and inlet air temperature on key performance indicators were evaluated. Increasing m˙afrom 0.0039 kg/s to 0.0071 kg/s led to a 73% increase in freshwater output, a 35% increase in Coefficient of Performance (COP), a 100% increase in Gain of Output Ratio (GOR), and a 75% increase in Recovery Ratio (RR), but a 20% decrease in dehumidifier efficiency. The maximum freshwater production rate of 870 g/h and a GOR of 1.4 were obtained at m˙a= 0.0071 kg/s and inlet air temperature of 50°C, representing a 117% increase compared to the lowest temperature and flow rate tested. The cost of freshwater for solar and electric operation modes was 0.075 and 0.094 USD/kg, respectively. The system's novelty lies in the integration of HDH desalination with a VAR and PV system, enabling continuous freshwater production even under cloudy or nighttime conditions. The findings demonstrate the potential of the proposed system for sustainable freshwater production in humid areas.

Annual energy performance simulation of ground source heat pump in a solar greenhouse

The use of ground source heat pumps (GSHP) in solar greenhouses had the potential to improve energy efficiency and reduce carbon emissions. However, because of the imbalance in cooling and heating applications, there would be an imbalance of heat in the subsoil. A numerical model of GSHP in a tomato growing solar greenhouse was created based on EnergyPlus. Annual energy performance simulations were performed with borehole free cooling, ground source heat pump cooling and heating operation modes. Thermal balance of the subsoil was achieved by adjusting the operating strategies of the three modes. Simulation results showed that the average COP of heating and COP of cooling of GSHP were 4.66 and 5.35 respectively.

Fast Attack Detection for Cyber-Physical Systems Using Dynamic Data Encryption.

To defend the cyber-physical system (CPSs) from cyber-attacks, this work proposes an unified intrusion detection mechanism which is capable to fast hunt various types of attacks. Focusing on securing the data transmission, a novel dynamic data encryption scheme is developed and historical system data is used to dynamically update a secret key involved in the encryption. The core idea of the dynamic data encryption scheme is to establish a dynamic relationship between original data, secret key, ciphertext and its decrypted value, and in particular, this dynamic relationship will be destroyed once an attack occurs, which can be used to detect attacks. Then, based on dynamic data encryption, a unified fast attack detection method is proposed to detect different attacks, including replay, false data injection (FDI), zero-dynamics, and setpoint attacks. Extensive comparison studies are conducted by using the power system and flight control system. It is verified that the proposed method can immediately trigger the alarm as soon as attacks are launched while the conventional χ2 detection could only capture the attacks after the estimation residual goes over the predetermined threshold. Furthermore, the proposed method does not degrade the system performance. Last but not the least, the proposed dynamic encryption scheme turns to normal operation mode as the attacks stop.