Mode Of Operation Research Articles

A modified Kushner-Moore approach to characterising small-scale blender performance impact on tablet compaction

Continuous Direct Compaction (CDC) has emerged as a promising route towards producing solid dosage forms while reducing material, development time and energy consumption. Understanding the response of powder processing unit operations, especially blenders, is crucial. There is a substantial body of work around how lubrication via batch blender operation affects tablet critical quality attributes such as hardness and tensile strength. But, aside from being batch operations, the design of these blenders is such that they operate with low-shear, low-intensity mixing at Froude number values significantly below 0.4 (Froude number Fr being the dimensionless ratio of inertial to gravitational forces). The present work explores the performance of a mini-blender which has a fundamentally different mode of operation (static vessel with rotating blades around a mixing shaft as opposed to rotating vessel with no mixing shaft). This difference allows a substantially wider operating range in terms of speed and shear (and Fr values). The present work evaluates how its performance compares to other blenders studied in the literature. Tablet compaction data from blends produced at various intensities and regimes of mixing in the mini-blender follow a common trajectory. Model equations from literature are suitably modified by inclusion of the Froude number Fr, but only for situations where the Froude number was sufficiently high (1 < Fr). The results suggest that although a similar lubrication extent plateau is eventually reached it is the intensity of mixing (i.e. captured using the Froude number as a surrogate) which is important for the lubrication dynamics in the mini-blender, next to the number of revolutions. The degree of fill or headspace, on the other hand, is only crucial to the performance of common batch blenders. Testing using alternative formulations shows the same common trend across mixing intensities, suggesting the validity of the approach to capture lubrication dynamics for this system.

Productivity and energy consumption as performance criteria to overcome bias caused by membrane resistance

Membrane scientists and engineers routinely compare the performance of membranes for different applications. Such comparisons are required to optimize surface chemistries and to evaluate and select the best membrane to scale-up industrial applications. In most cases, the potential of the feed to foul membrane surfaces is also critical. When different membranes under consideration have different resistances Rm, such comparisons must be done with care. Here we elucidate the impact of Rm on fouling kinetics for a range of fouling mechanisms and experimental protocols. We show that traditional plots of flux versus time for constant pressure operation, or pressure versus volume in constant flux operation, obscures two important performance criteria: accumulated volume over a defined time period (i.e., productivity) and energy consumption; practical implications include the risk that higher performance may be attributed to membranes that actually have lower productivity and/or that consume more energy, and that lower performing membranes may be inadvertently chosen from screening studies as offering superior performance. To facilitate membrane comparison with different Rm, we have developed a graphical approach using normalized coordinates. This approach yields linear plots having slopes that are a function of fouling parameters only, and are independent of membrane resistance Rm. Therefore, such normalization coordinates, presented for each fouling mechanism and each operation mode, can be employed to isolate fouling potential. In addition, we developed a new graphical approach employing contour plots of iso-volume or iso-energy lines to visualize the potential trade-offs between antifouling performance, membrane permeability, and either productivity in the case of constant pressure operation, or specific energy in the case of constant flux operation. This study provides a framework for judging the performance of different membranes under fouling conditions, considering fouling, energy consumption and productivity as metrics, independent of membrane resistance. This framework will help guide process design and the design and preparation of antifouling membranes.

Shadow Banking in the United States: Emerging Factors, Operation Modes and the Current Situation of Supervision - Based on the Comparison with Chinese Shadow Banking System and Market

In 2009, Ben Bernanke, chairman of the Federal Reserve, described shadow banking as a financial intermediary that converts savings into investments in addition to regulated deposit-taking institutions. To put it simply, the essence of shadow banking is a financial innovation that breaks through traditional financial institutions in order to maximize profits in the financial market environment. In this paper, we compare the U.S. and Chinese shadow banking system and their market system. From that, we analyze their similarities and differences from the aspects of emerging factors, classification and scale, and operation mode. Based on the above analysis, we then discuss the current situation of supervision of shadow banking in the United States and find that the U.S. shadow banking is negligent in institutional constraints and has practical difficulties in legal supervision. Finally, we put forward some suggestions on the future development and financial structure optimization of shadow banking.

New Generation Nebulizers.

Standard nebulizers are intended for general purpose use and typically are continuously operated jet or ultrasonic nebulizers. Evolutionary developments such as breath-enhanced and breath-triggered devices have improved delivery efficiency and ease of use, yet are still suitable for delivery of nebulized medications approved in this category. However, recent developments of vibrating membrane or mesh nebulizers have given rise to a significant increase in delivery efficiency requiring reformulation of former drug products or development of new formulations to match the enhanced delivery characteristics of these new devices. In addition, the electronic nature of the new devices enables tailoring to specific applications and patient groups, such as guiding or facilitating optimal breathing and improving adherence to the therapeutic regimen. Addressing these patient needs leads to new nebulization technologies being embedded in devices with fundamentally distinct functionality, modes of operation and patient interfaces. Therefore, new generation nebulizers can no longer be regarded as one category with fairly similar performance characteristics but must be clinically tested and approved as drug/device combinations together with the specific drug formulation, similar to the approval of pressurized metered-dose inhalers and dry powder inhalers. From a regulatory viewpoint, it is required that drug and device are associated with each other as combinations by clear, mutually conforming labels or, even more desirably, by distinct container-closure systems (closed system nebulizer).

Optimal operation of flexible interconnected distribution grids based on improved virtual synchronous control techniques

With distributed energy sources connected to the distribution grid on a large scale for distributed photovoltaic power randomness, this paper proposes a flexible interconnection system optimization operation strategy. First, the virtual synchronous control technology is improved to improve the DC bus voltage stability; second, it analyzes the system operation mode to judge the output logic of PV and storage units, takes DC bus power balance as the underlying logic, and puts forward the power coordination optimization strategy and fault power supply restoration strategy with full consideration of factors such as the load balance degree of the distribution station area, the economic operation of the main transformer, and the amount of power lost in the faulty station area. It also establishes a multi-objective optimization model to obtain the power commands of each port and achieves the power flexibility mutualization of the flexible interconnected system through the accurate regulation of the soft normally open point (SNOP). Finally, a simulation model of the flexible interconnection system is built using MATLAB/Simulink to verify the effectiveness of the proposed optimization strategy.

Load Factor Characteristics of 200 kw Class Excavators in Real-Work Operation Mode

Load Factor Characteristics of 200 kw Class Excavators in Real-Work Operation Mode

Assessment of ergonomic risks in car radio manufacturing using the Suzanne Rodgers and NIOSH criteria: a practical application

Companies from Industrial Pole of Manaus look for automation to reduce ergonomic risks, even if the degree of autonomy will depend on organizational technical projects, that is, we visualize two different strands to develop ergonomic actions with the objective of improving working conditions related to health and productivity. Many interests about ergonomics are due to legislation, to adapt the work conditions, it is necessary to measure the ergonomic risks through established criteria. The present study aims to verify the contribution of ergonomic risk assessment instruments in practice, even though the process is quite robust, using the NIOSH and Suzanne Rodgers Criteria we visualize several potential to mitigate the risks inside this manufacturing process. The research was conducted through a literature review, and case study, raising the operative mode of all the workstations, mainly considering the comments of the employees involved, since all the methods present had potential for application, but a standardization of the evaluation for data collection become the main factors in determining the risk factors related to musculoskeletal disorders. According to the knowledge acquired and accumulated during the data collection, observed the ergonomic thermometer of the manufacture, where the moderate risk was evident, even if it is a process with automation, but this study will guide to a more effective work in search of the reduction of the ergonomic risk within the organization by the multifunctional team, in the search for the ergonomically correct process.

Connecting digital twins to control collections systems and water resource recovery facilities: From siloed to integrated urban (waste)water management

ABSTRACT The use of digital twins is a rapidly emerging field for improved real-time control (RTC) and decision support for the operation of collection systems and water resource recovery facilities (WRRFs). Digital twins for collection systems can help minimize the impacts of flow variation due to extreme weather events, attenuate flows to the WRRF, and reduce sewer overflows and the associated effects. Similarly, digital twins for WRRFs can help improve process, energy, and cost efficiency, fully utilise plant volumes, reduce carbon footprint, and support operator training. The current study provides an overview of two digital twin applications for collection systems (Future City Flow) and WRRFs (TwinPlant) and presents a first example of digital twin integration for proactive collection system-WRRF operation under wet-weather conditions. Current applications of the integrated digital twin are described, including (i) proactive implementation of wet-weather operation mode in WRRF based on inflow forecast and (ii) evaluation of the impacts of RTC in collection systems on WRRF performance. Other potential application examples are described together with the challenges related to the use of this solution. Overall, this new approach has a wide potential to support the cooperation within water utilities towards the adoption of integrated wastewater management.

Educating through commons-based pedagogical practices

This paper explores the transformative potential of primary education pedagogy to instill the logic and ethics of the commons, emphasizing a paradigm shift away from competitive or individualistic learning frameworks towards those fostering care, reciprocity, and mutual support. Through a year-long action research project in a sixth-grade classroom, this study examines the transfer of Educational commons elements into formal schooling. It argues that such integration requires pedagogical practices that cultivate distinct cognitive and operational modes, enabling students to engage in self-organization of the school classroom and collective knowledge management. The research details the development and operationalization of what is termed as “commons-based pedagogical practices”. These practices are designed to encourage a learning environment that is inclusive and collaborative, characterized by peer learning, co-creation of knowledge, assemblies. peer dialogue and peer accountability. The study juxtaposes theoretical frameworks with practical applications, providing insights into how these pedagogical approaches can be effectively implemented to transform educational settings. The emphasis is placed on creating a classroom dynamic that supports the collective exploration and negotiation of diverse educational concepts, thereby fostering an atmosphere conducive to communal learning and ethical engagement.

Measurement of the neutron total cross section of 9Be at the Back-n white neutron source of CSNS

Abstract The neutron total cross section data of 9Be play an important role in nuclear structure model research of light nuclei and nuclear power installations. A measurement of the neutron total cross section of 9Be in the 0.3 eV-120 MeV energy region has been carried out by using time-of-flight method and transmission method with the Neutron Total Cross Sectional Spectrometer (NTOX) based on the multi-cell fast fission chamber at the China Spallation Neutron Source (CSNS)- Back-n white neutron source (Back-n). The fission count-neutron energy distributions of 235U and 238U without sample and with Be samples in three thicknesses were measured in the double-bunch operation mode during beam power of 100 kW. The Bayesian method is used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV. The neutron total cross section of 9Be results is well consistent with ENDF/B-VIII.0 evaluation library data in 0.3 eV-20 MeV energy region. In the energy range of 0.3 eV to 10 keV, the deviation between our results and the evaluation results of ENDF/B-VIII.0 is within 2.5%, which is within 15% from 0.01-20 MeV. In the resonance energy region, the measured resonance energies in our experiment are 0.63 MeV, 0.82 MeV and 2.8 MeV respectively. The results show that the total cross section uncertainties of three thicknesses Be samples are within 2.2% in the energy region below 1 MeV. The total cross section uncertainty of 30 mm Be from 235U is the smallest and less than 5% in the energy region 0.3 eV-120 MeV. The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.

Life of field emission forecast development and reduction option screening for a multi-train LNG hub

The Karratha Gas Plant (KGP) is a complex integrated facility which produces liquified natural gas (LNG), domestic gas (Domgas), condensate, propane and butane products. The multi-train facility has been operating for 40 years with several phases of expansion resulting in a range of gas turbine technology and energy efficiency levels across the facility. The challenge for the next phase of KGP operation is to manage declining North West Shelf (NWS) feed gas levels, and the addition of Other Resource Owners feed gas while reducing emissions and maintaining energy efficiency. A flexible emissions forecasting tool has been developed which allows unit and whole of facility emissions reduction and energy efficiency options to be assessed. The tool builds on current quarterly timestep production forecasts and models ambient temperature, unit turndown and turn-off strategies, and potential implementation of lower emissions technology. The ability to generate and compare life of field emissions profiles for extrapolated operating modes and proposed modifications allows unit strategies and phasing of emissions reduction modifications to be investigated and screened before further economic assessment and creation of marginal abatement cost curves (MACC).

Detuning piezoelectric receivers by resistive load adjustment for electrodynamic wireless power transfer

Abstract This article investigates electrical detuning techniques for low-frequency electrodynamic wireless power transfer (EWPT) systems. This study focuses on protecting the receiver from potential damage when quick increases in magnetic fields occur due to transmitter-receiver distance variation or in-rush transmitter coil currents. In the case of such event, to avoid damaging the mechanical receiver, the solution investigated in this article is to adjust the electrical load connected to the receiver. This adjustment enables precise tuning and detuning of the receiver’s resonant frequency and damping characteristics, thereby allowing to reduce its mechanical displacement amplitude and protecting it from damage. Based on well-known models of EWPT systems, we develop an analysis of two key operational modes of the proposed tuning/detuning approach: Maximum Transmitted Power (MTP) mode, where the receiver circuitry’s input impedance is optimized for peak power transfer, and Minimum Displacement (MD) mode, which involves electrically detuning the receiver’s resonant frequency to limit its mechanical displacement. We establish transition conditions between MD and MTP modes based on the receiver voltage amplitude, enabling automated monitoring and adjustment of the receiver’s detuning. Experimental validation has been conducted with an EWPT experimental setup and a custom piezoelectric receiver. The results, in good agreement with the proposed analytical model predictions, confirm the effectiveness of the proposed detuning algorithm, which successfully reduces the receiver displacement by 60% in response to sudden magnetic field increases.

Theoretico-experimental analysis of bistability in the oscillatory response of a TaOx ReRAM to pulse train stimuli

Fading memory is the capability of a physical system to approach a unique asymptotic behaviour, irrespective of the initial conditions, when stimulated by an input from a certain class. Standard stimuli from the AC periodic class typically induce fading memory effects in non-volatile memristors, as uncovered for the first time back in 2016. Very recently, a deep investigation of resistance switching phenomena in a TaOx resistive random access memory cell revealed the capability of the nano-device to exhibit one of two possible oscillatory behaviours, depending upon the initial condition, when subject to a particular periodic excitation. This interesting finding was, however, left unexplained. Bistability is the simplest form of local fading memory. In a system, endowed with local fading memory under a given stimulus, the initial condition does not affect the long-term behaviour of the state as long as it is drawn from the basin of attraction of either of the distinct coexisting state-space attractors (two limit cycles for the periodically forced memristor acting as a bistable oscillator). Here, the history of the system, encoded in the initial condition, is, thus, erasable only locally through ad hoc stimulation. Motivated by the discovery of local history erase effects in our resistive random access memory cell, this study applies a powerful system-theoretic tool, enabling the analysis of the response of first-order systems to square pulse train-based periodic stimuli, known as the time-average state dynamic route, to an accurate physics-based mathematical model, earlier fitted to the nano-device, to determine a strategy for specifying the parameters of an excitation signal, consisting of the sequence of two square pulses of opposite polarity per period so as to induce various forms of monostability or multistability in the non-volatile memristor. In particular, as an absolute novelty in the literature, experimental measurements validate the theoretical prediction on the capability of the device to operate as one of two distinct oscillators, depending upon the initial condition, under a specific pulse train excitation signal. The coexistence of multiple oscillatory operating modes in the periodically forced resistive random access memory cell, an example par excellence of their unique non-linear dynamics, may inspire the development and circuit implementation of novel sensing and mem-computing paradigms.

Electroconductive and photoelectric properties of Pt/(100) β-Ga2O3 Schottky barrier diode based on Czochralski grown crystal

Pt/(100) β-Ga2O3 Schottky barrier diodes were fabricated using a plate cleaved from the crystal grown by Czochralski method. Their electroconductive and photoelectric characteristics were studied. The following values were obtained: the Schottky barrier height (1.69/1.62/1.74 eV), ideality coefficient (1.09/1.14), saturation current density (9.91 × 10–15 A/cm2), diode series resistance (7.98 kΩ), and net donor concentration [(1.8–2.4) × 1018 cm–3]. The diodes demonstrate a high rectification ratio of 1010 at an applied voltage of ± 1 V and a relatively low experimental value of the leakage current density ∼10–11 A/cm2. These structures are solar-blind and also capable of operating in self-powered mode. The diodes are highly sensitive to short-wave ultraviolet radiation with a wavelength λ ≤ 265 nm. The maximum values of responsivity (20.4 A/W), external quantum efficiency (1.2 × 104%), and detectivity (9.6 × 1015 Hz0.5 × cm × W–1) of diodes were registered under exposure to irradiation at λ = 210 nm and at applied voltage of −1 V. The responsivity and external quantum efficiency values in the self-powered operation mode were 12.3 A/W and 7.2 × 103%, respectively. The diodes showed low rise and decay times in self-powered operation mode for photodiode based on Ga2O3: 14 and 30 ms, respectively.

Preliminary characterization of anelastic effects in the flexure mechanism for a new Kibble balance at NIST

A new Kibble balance is being built at the National Institute of Standards and Technology (NIST). For the first time in one of the highly accurate versions of this type of balance, a single passive flexure mechanism is used for both modes of operation: the weighing mode and the velocity mode. The mechanism is at the core of the new balance design as it represents a paradigm shift for NIST away from using knife edge-based balance mechanisms, which exhibit hysteresis in the measurement procedure of the weighing mode. Mechanical hysteresis may be a limiting factor in the performance of highly accurate Kibble balances approaching single digit nanonewton repeatability on a nominal 100g mass, as targeted in this work. Flexure-based mechanisms are known to have very good static hysteresis when used as a null detector. However, for larger and especially longer lasting deformations, flexures are known to exhibit anelastic drift. We seek to characterize, and ideally compensate for, this anelastic behavior after deflections during the velocity mode to enable a 10−8 accurate Kibble balance-measurement on a nominal 100g mass artifact with a single flexure-based balance mechanism. A measurement of the anelastic after-effect after static excitation hints that the apparatus produced a result for anelastic relaxation comparable to previously published work. Furthermore, a series of oscillatory displacements similar to those occurring in a velocity mode of a Kibble balance measurement are imposed upon the flexure mechanism and show a significant anelastic relaxation torque resulting in multiple micronewton of force relaxation. The amplitude of this force relaxation could be reduced by counterbending the flexures before performing a force measurement.

Beyond the formal economy. Social cooperatives for labour integration under the pressure of market competitiveness

Purpose Using the theoretical framework of the substantive economy, this study aims to point out the main aspects of the substantive mode of operation that help the integration of disadvantaged people while at the same time shedding light on the barriers that hinder economically efficient functioning in a market economy. Design/methodology/approach Research focuses on Hungarian rural work integration social cooperatives, which are engaged in producing activity by the employment of disadvantaged people. In the research, mixed methods were applied: results of a questionnaire survey covering 102 cooperatives, as well as 20 semi-structured interviews and experiences from the field. A total of 17 indicators were used to explore the substantive operational features, promoting mechanisms and problems in the following areas: organisational goals and outcomes; integrating roles and functions; productive functions; and the embeddedness of cooperatives. Findings As for results, substantive operational mechanisms and tools that support the integration of disadvantaged people have been identified such as mentoring, social incentives, the ability to create local value or the expansion of local community services. At the same time, several barriers have been detected that make it difficult to operate economically, such as cooperatives being a stepping stone for workers, excessive product heterogeneity or the lack of vertically structured bridging relationships. Originality/value The value of the study is to counterpoint the mechanisms promoting social purposes of work-integration social cooperatives and the obstacles to their long-term sustainability within the framework of the substantive economy, to better understand their functioning and the less quantifiable factors of their performance.

A Single-Step Method for Harvesting Influenza Viral Particles from MDCK Cell Culture Supernatant with High Yield and Effective Impurity Removal

A Single-Step Method for Harvesting Influenza Viral Particles from MDCK Cell Culture Supernatant with High Yield and Effective Impurity Removal

Transient Performance Analysis of Centrifugal Left Ventricular Assist Devices Coupled With Windkessel Model: Large Eddy Simulations Study on Continuous and Pulsatile Flow Operation.

Computational fluid dynamics (CFD) simulations are widely used to develop and analyze blood-contacting medical devices such as left ventricular assist devices (LVADs). This work presents an analysis of the transient behavior of two centrifugal LVADs with different designs: HeartWare VAD and HeartMate3. A scale-resolving methodology is followed through Large Eddy Simulations, which allows for the visualization of turbulent structures. The three-dimensional (3D) LVAD models are coupled to a zero-dimensional (0D) 2-element Windkessel model, which accounts for the vascular resistance and compliance of the arterial system downstream of the device. Furthermore, both continuous- and pulsatile-flow operation modes are analyzed. For the pulsatile conditions, the artificial pulse of HeartMate3 is imposed, leading to a larger variation of performance variables in HeartWare VAD than in HeartMate3. Moreover, CFD results of pulsatile-flow simulations are compared to those obtained by accessing the quasi-steady maps of the pumps. The quasi-steady approach is a predictive tool used to provide a preliminary approximation of the pulsatile evolution of flow rate, pressure head, and power, by only imposing a speed pulse and vascular parameters. This preliminary quasi-steady solution can be useful for deciding the characteristics of the pulsatile speed law before running a transient CFD simulation, as the former entails a significant reduction in computational cost in comparison to the latter.

Cost-Effective Automatic Portable Air Purifier

Indoor air pollution has become a severe concern on human health due to improper ventilation, pets and fine dust particles. The demand for efficient air purifiers has surged, yet many existing solutions are generally pricey and lack portability. The suggested air purifier uses modern filtration technologies, including activated carbon filters, to remove a wide range of airborne contaminants, such as dust, allergies, pet hair, and volatile organic compounds (VOCs). By adopting a tiny and lightweight design, the purifier offers outstanding portability, enabling customers to experience clean and fresh air wherever they go. The proposed air purifier possesses a distinctive design that integrates a high electric field generator and UV light source. The high electric field technique effectively accumulates and neutralizes airborne particles, including dust, pollen, mold spores, and germs. Simultaneously, the UV light component kills dangerous microbes, such as viruses and bacteria, by breaking their DNA structure, offering cleaner and healthier air. To achieve best performance and energy economy the air purifier adopts an automated operation mode. The device operates only upon the detection of motion a human being.

Modeling the cortical response elicited by wrist manipulation via a nonlinear delay differential embedding.

Regarding motor processes, modeling healthy people's brains is essential to understand the brain activity in people with motor impairments. However, little research has been undertaken when external forces disturb limbs, having limited information on physiological pathways. Therefore, in this paper, a nonlinear delay differential embedding model is used to estimate the brain response elicited by externally controlled wrist movement in healthy individuals. The aim is to improve the understanding of the relationship between a controlled wrist movement and the generated cortical activity of healthy people, helping to disclose the underlying mechanisms and physiological relationships involved in the motor event. To evaluate the model, a public database from the Delft University of Technology is used, which contains electroencephalographic recordings of ten healthy subjects while wrist movement was externally provoked by a robotic system. In this work, the cortical response related to movement is identified via Independent Component Analysis and estimated based on a nonlinear delay differential embedding model. After a cross-validation analysis, the model performance reaches 90.21% ± 4.46% Variance Accounted For, and Correlation 95.14% ± 2.31%. The proposed methodology allows to select the model degree, to estimate a general predominant operation mode of the cortical response elicited by wrist movement. The obtained results revealed two facts that had not previously been reported: the movement's acceleration affects the cortical response, and a common delayed activity is shared among subjects. Going forward, identifying biomarkers related to motor tasks could aid in the evaluation of rehabilitation treatments for patients with upper limbs motor impairments.