Operational Demands Research Articles

Transcranial Doppler Remote Positioning System with Virtual Reality Integration for Vestibular Studies.

Transcranial doppler (TCD) ultrasound probes are an invaluable tool in cerebral blood flow (CBF) studies. Their operation demands maintaining consistent pose on the subject throughout the experimental protocol. However, the displacement of the TCD probe during vestibular studies is common and substantially prolongs the experiment or even terminates it. This is a significant challenge for integrating motion-based vestibular studies with CBF investigations. In response, a mechatronics system is designed to allow remote repositioning of the TCD probe during data collection experiments while the subject is wearing a head mounted virtual reality (VR) display and seated in a vestibular disorientation device. This paper presents the design, prototype, and operation of this mechatronics apparatus.Clinical Relevance- The mechatronics apparatus of this paper can enable motion-based vestibular studies that entail the use of CBF velocity measurement and head-mounted virtual reality display.

Impact of Working Capital Management on Profitability: A Studyof the Select Indian Pharmaceutical Companies

The smooth running of business operations demands an efficient management of working capital by properly managing the inventory, accounts receivables and accounts payables of the business. This helps companies not only fulfil their short-term financial commitments but also boost their earnings. Therefore, the present study aims at verifying the impact of working capital management on the profitability of the companies under pharmaceutical industry in India. For empirical analysis, the data of 618 pharmaceutical companies is taken over a period of seven years from 2014–2015 to 2020–2021 and multivariate panel data regression technique is applied on data for estimating the results. The findings of the study validate that the profitability of companies is significantly influenced by working capital management. These findings will provide an insight to corporate managers and owners of pharmaceutical companies in deciding appropriate working capital strategy.

Exploring the potential of nano technology: A assessment of nano-scale multi-layered-composite coatings for cutting tool performance

Nano-scale Multi-layered Composite Coatings (Nano scale MLCC) offer potential benefits for cutting tool performance. Such coatings can be designed to improve tool durability and cutting efficiency by providing additional wear protection and improved heat dissipation. The Nano coatings can also be tailored to reduce friction, which can enhance productivity and reduce tool wear. The unique Nano-scale topography of MLCC helps to reduce the contact area between the cutting tool and the workpiece, thus reducing friction and heat. The coatings also include specific additive components that enhance the properties of the coating, such as corrosion resistance, lubricant retention, and improved thermal stability.This critical review explores the potential of Nano-scale multi-layered-composite coatings for improving the performance of cutting tools. The literature in this field is reviewed and discussed with respect to the performance benefits and challenges associated with the implementation of these nanotechnology coatings. The latest progress in nanofabrication, nanomaterials, and other technologies are discussed in relation to their ability to provide new and improved cutting tool applications. The review summarizes the current state of the art on Nano-scale multi-layered-composite coatings and their influence on cutting tool performance, with particular focus on machining productivity, tool life, cutting forces and wear rates. Recommendations are provided on which Nano-scale coatings may best fit the demands of particular machining operations, and on future research directions in this field. The review also discusses the challenges and future advancements of Nano-scale coatings and other methods for improving cutting tool performance. In conclusion, this review provides a comprehensive insight into the future potential of MLCC for cutting tool performance enhancement.

Long-term replenishment strategy of SiC-doped Mn-Fe particles for high-temperature thermochemical energy storage

Thermal chemical energy storage (TCES) is a promising technology for large-scale energy storage, but long-term use of TCES materials can lead to attrition and reaction performance deterioration, compromising heat storage capacity and system continuity. To tackle this challenge, it is imperative to develop effective replenishment strategies and investigate the evolution of TCES materials. In this study, SiC-doped Mn-Fe particles exhibited superior performance, with only 1.87% mass loss ratio after 4.32×105 rotations attrition testing and a reaction conversion of 91.7% even after 800 reaction cycles. However, assessing material suitability for TCES systems necessitates analyzing both attrition resistance and reaction performance. A replenishment strategy was proposed, based on the attrition conversion factor and analysis of dissipated energy of particles in concentrated solar power (CSP) plants. Compared to undoped Mn-Fe particles, the annual replenishment ratio was reduced by one order of magnitude for SiC-doped particles, to only 1.26% (0.5 wt% SiC) and 0.994% (1 wt% SiC). The replenishment strategy and strengthened particles result in curtailed particle fines and particle flow interruption, and enhanced economics. Continuous replenishment strategy can undoubtedly cater to the requisite heat storage capacity demands for protracted system operation and extend system stability, promoting the advancement of TCES technology.

Integrating Air Assets for Augmenting Surveillance Capabilities of the Sri Lanka Coast Guard

Law enforcement at sea is of prime importance for an Island nation. At present Sri Lanka Coast Guard (SLCG) satisfies its aerial demands through Sri Lanka Air Force (SLAF) under various limitations causing a gap between the demand and supply of aerial surveillance requirements. Hence this exploratory qualitative study has followed a deductive approach, interpretivism philosophy, and grounded theory strategy to realize the objectives of determining the present status of the SLCG surveillance mechanism, determining how the air assets could be effectively integrated into the SLCG surveillance mechanism, and to study the impact of integrating air assets into the SLCG surveillance mechanism. A Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis resulted in strengths as already enacted act, experienced crew, and intention of authorities to integrate air assets into SLCG. Weaknesses were found to be a lack of naval assets, manpower, and the absence of air assets. Opportunities are the possible training opportunities, collaboration with the Sri Lanka Navy and SLAF, obtaining air assets through mutual cooperation, and leeway of integrating into a common maritime policy. Changing dynamics of non-traditional security threats, and geo-political implications due to inadequate presence and inadequate budget were identified as threats in SWOT analysis. Based on the outcome of the SWOT analysis, researchers came up with five recommendations such as formulating a framework for integrating air assets into SLCG, formulating a doctrine and Standard Operating Procedure for maritime-air operations of SLCG, developing a dialogue with SLAF for mutual cooperation and secondment of air and ground crew required for SLCG air operations, pursue diplomatic means for obtaining air assets and related training and finally conducting joint and multinational training and operations with local and international stakeholders. Therefore, strengthening SLCG capabilities and capacities by integrating air assets through a feasible framework in meeting its future operational demand is essential.

Assessing the physiological basis for resilience in military personnel.

Military personnel experience training and operational demands that are different from civilian populations, including frequent deployment, exposure to austere environments, and dislocation from family. These unique occupational demands may result in negative impacts on health, performance, and career success. As such, resilience, defined as a system's capacity to resist, recover, recover better, or adapt, to perturbation from a challenge or stressor, is a critical factor in assuring the health and safety of military personnel. In recent years, the Department of Defense (DoD) has funded research programs assessing the physiological basis of resilience. This review will overview research programs, review salient findings from recent studies, and highlight potential future areas of research. Physiological factors influencing or predicting resilience in US military populations, including physical performance, anthropometrics and body composition, nutrition and dietary supplements, and other biomarkers will be highlighted. Finally, this manuscript will detail potential future studies, including interventions, aimed at optimising physiological resilience in military personnel.

Environmental Impacts Assessment in Suspension PVC Production Process Using Computer-Aided Process Engineering

The new demands for sustainable operation in the chemical industry due to increasing environmental regulations and agreements have generated the need to adapt existing processes to more intelligent production. The plastics sector is in a complex position due to its contribution to economic development and the climate crisis. Therefore, environmental assessment has become an important tool due to the benefits it provides by quantifying the environmental performance of processes, allowing it to balance operational and environmental needs. Polyvinyl chloride (PVC) is one of the most globally used polymers thanks to its resistance, flexibility, and cost-effectiveness. The polymer is synthetized by suspension polymerization, which is characterized by high productivity and controllability. However, it presents problems associated with intensive energy consumption and the emission of toxic substances and greenhouse gases. Therefore, an environmental assessment of the suspension PVC production process was performed using the waste reduction algorithm (WAR). The potential environmental impact (PEI) was quantified using the generation rate and the output velocity for four cases and three different fuels. It was found that the process transforms raw materials with high impacts, such as VCM, into substances with lower PEI, such as PVC. However, the process has a high generation of PEI due to the effects of energy consumption (−2860, −2410, 3020, and 3410 for cases 1–4, respectively). The evaluation of the toxicological impacts shows that the ATP category is the only one that presents a positive generation value (75 PEI/day); the product contributes to the formation and emission of impacts. The atmospheric categories showed that the energy consumption of the process is the most critical aspect with a contribution of 91% of the total impacts emitted. The AP and GWP categories presented the highest values. It was determined that the most suitable fuel is natural gas; it has lower impacts than liquid and solid fuels (coal). Additionally, it can be concluded that the PVC production process by suspension is environmentally acceptable compared to the polyethylene or polypropylene processes, with output impacts 228 and 2561 times lower, respectively.

The ORthopaedic Trauma Hospital Outcomes - Patient Operative Delays (ORTHOPOD) study

AimsThis is a multicentre, prospective assessment of a proportion of the overall orthopaedic trauma caseload of the UK. It investigates theatre capacity, cancellations, and time to surgery in a group of hospitals that is representative of the wider population. It identifies barriers to effective practice and will inform system improvements.MethodsData capture was by collaborative approach. Patients undergoing procedures from 22 August 2022 and operated on before 31 October 2022 were included. Arm one captured weekly caseload and theatre capacity. Arm two concerned patient and injury demographics, and time to surgery for specific injury groups.ResultsData was available from 90 hospitals across 86 data access groups (70 in England, two in Wales, ten in Scotland, and four in Northern Ireland). After exclusions, 709 weeks' of data on theatre capacity and 23,138 operations were analyzed. The average number of cases per operating session was 1.73. Only 5.8% of all theatre sessions were dedicated day surgery sessions, despite 29% of general trauma patients being eligible for such pathways. In addition, 12.3% of patients experienced at least one cancellation. Delays to surgery were longest in Northern Ireland and shortest in England and Scotland. There was marked variance across all fracture types. Open fractures and fragility hip fractures, influenced by guidelines and performance renumeration, had short waits, and varied least. In all, nine hospitals had 40 or more patients waiting for surgery every week, while seven had less than five.ConclusionThere is great variability in operative demand and list provision seen in this study of 90 UK hospitals. There is marked variation in nearly all injuries apart from those associated with performance monitoring. There is no evidence of local network level coordination of care for orthopaedic trauma patients. Day case operating and pathways of care are underused and are an important area for service improvement.Cite this article: Bone Jt Open 2023;4(6):463–471.

Low-temperature solar thermal-power systems for residential electricity supply under various seasonal and climate conditions

In this work, the performance of low-temperature (<100 °C) solar thermal-power systems to satisfy residential electric loads was analyzed. The solar-driven system was designed to provide a fraction of the total electricity demand in a complementary operation with the electric grid. The analysis was conducted for an coperation during seven days each season, considering real solar and climate variables and residential loads at different climate zones in the United States. The efficiency of the system strongly depends on the solar radiation profile and the ambient temperature. Maximum efficiencies of around 9.5% were obtained in the cold and marine climate zones due to the high solar energy input and low heat dissipation temperatures. In these two zones, the system could supply more than 98% of the electricity demand all seasons. At mixed-humid and hot-humid regions, the system supplied around 50% of the electric load in three of the four seasons, but it only supplies about 27% of the electricity needs in the mixed-humid zone during summer and hot-humid zone during winter. The effect of the solar collector field area and the tank volume was also analyzed. In general, larger solar fields positively impact the efficiency. However, the impact of the tank volume varies depending on the solar radiation profile and the load requirements. Average efficiencies for the seven-day operation can be larger than 6% with a proper selection of the solar collector area and tank volume for an Organic Rankine Cycle with a capacity of about 2.6 kW. Finally, an economic analysis of the system was conducted, and the results were compared with a solar PV + battery system of similar capacity. It is expected that the cost for the analyzed solar-thermal system decreases in the coming years with the increased interest on low temperature applications.

Effect of high-speed steel screw drill geometry on cutting performance when machining austenitic stainless steel

Drilling into the solid material is one of the basic technological operations, which creates a cylindrical hole in an appropriate time with required quality. Drilling operation demands a favourable removal of chips from the cutting area because a creation of an undesirable shape of chips can impart a lower quality of the drilled hole corresponding with the generation of excess heat due to the intense contact of the chip with drill. The solution for a proper machining is a suitable modification of the drill geometry i.e., point and clearance angles as presented in current study. The tested drills are made of M35 high-speed steel characterized by a very thin core at the point of the drill. An interesting feature of the drills is the use of cutting speed higher than 30 m min−1, with the feed of 0.2 mm per revolution. The surface roughness (Ra and Rz lower than 1 µm and 6 µm respectively), cylindricity (0.045 mm), roundness (0.025 mm), perpendicularity of the hole axis (0.025 mm), diameters and position of the individual holes were achieved for a drill with point angle 138.32°and clearance angle 6.92 respectively. The increase of the drill point angle by 6° resulted in the decrease in the feed force of more than 150 N. In addition, an increase of the clearance angle by 1° resulted with a decrease in the feed force of 70 N. The results of the experiment showed that with the correct geometry of the tool the effective machining without using internal cooling can be realised.

“See us as humans. Speak to us with respect. Listen to us.” A qualitative study on UK ambulance staff requirements of leadership while working during the COVID-19 pandemic

BackgroundThe COVID-19 Ambulance Response Assessment (CARA) study aimed to enable the experiences of UK frontline ambulance staff working during the first wave of the pandemic to be heard. Specifically, CARA...

Enhanced Energy-Saving Mechanisms in TSCH Networks for the IIoT: The PRIL Approach

Lifetime of motes in wireless sensor networks can be enlarged by decreasing the energy spent for communication. Approaches like time slotted channel hopping pursue this goal by performing frame exchanges according to a predefined schedule, which helps reducing the duty cycle. Unfortunately, whenever the receiving radio interface is active but nobody in the network is transmitting, idle listening occurs. If the traffic pattern is known in advance, as in the relevant case of periodic sensing, proactive reduction of idle listening (PRIL) noticeably lowers energy waste by disabling receivers when no frames are expected for them. Optimal PRIL operation demands that, at any time, the transmitter and receiver sides of a link have a coherent view of its state (either enabled or disabled). However, this is not ensured in the presence of acknowledgment frame losses. This paper presents and analyzes some strategies to cope with such events. An extensive experimental campaign has been carried out through discrete event simulation to determine what consequences above errors may have from both a functional and performance viewpoint. Results show that, although no strategy is optimal in all circumstances, different solutions can be profitably adopted depending on the specific operating conditions.

Investment Efficiency Assessment Model for Pumped Storage Power Plants Considering Grid Operation Demand under Fuzzy Environment: A Case Study in China

As China develops new power systems such as wind power, photovoltaic, pumped storage, and other clean energy installations, its clean energy ratio is steadily increasing. However, the high percentage of clean energy brought by the new power system does not make everything right. Clean energy sources such as wind, photovoltaics, pumped storage, and other sources are inevitably unstable, and they create large amounts of waste if they are not directly used. Additionally, at the peak of electricity consumption, if the power is not generated in time, it will negatively impact society. Therefore, the significance of building pumped storage power plants will be greatly enhanced. The scope of the text is evaluates the investment efficiency of pumped storage power plants. We selected data from North China region, Northeast China region, East China region, Central China region, Northwest China region, and Southern China region to comprehensively evaluate the return on investment of pumped storage power plants in six different regions. In order to solve this problem, this paper will use various models and algorithms, such as cloud model and AHP method to establish a set of evaluation indicators around three basic points to evaluate the benefits of pumped storage, and then use the fuzzy comprehensive evaluation method to evaluate the level of each indicator. Finally, the benefits of establishing pumped storage power plants are comprehensively evaluated. Following the comprehensive evaluation, we have identified the efficiency scores of investing in pumped storage power plants in different regions of China, thus not only proving that pumped storage power plants have a broad market space in China, but also further proving where we should focus on building pumped storage power plants. Based on these criteria, a series of recommendations are made.

Thermodynamic and economic analysis of an off–grid photovoltaic hydrogen production system hybrid with organic Rankine cycle

Water electrolysis technology is a potential approach for green hydrogen production and photovoltaic power consumption. However, due to the volatility and uncertainty of the solar energy, supplying photovoltaic power directly to the water electrolysis auxiliary system is instable. An innovative off–grid photovoltaic proton exchange membrane electrolytic cells hydrogen production system is proposed to address that issue. The system integrates an organic Rankine cycle system with evacuated tube collector modules to supply power for the auxiliary system. The electrical power generated by the photovoltaic module is directly supplied to the proton exchange membrane electrolytic cells. The matching of the organic Rankine cycle system output power and auxiliary system power demand has been conducted by comparing the temperature control methods and parameters. The thermodynamic and economic performances of the photovoltaic hydrogen production system have been investigated with the meteorological data of Nanjing. The results demonstrate the organic Rankine cycle system can completely satisfy the power demand of the auxiliary system operation. The annual hydrogen production of the system can reach 26.07 tons (316203.0 Nm3) and the hydrogen average electricity consumption is 4.75 kWh/Nm3. The system has a maximum energy and exergy efficiency of 8.8 % and 9.1 %, respectively. This system is suitable for retrofitting photovoltaic plants, the payback period of the retrofit project is 12 years, which shows higher profitability than that of grid-supplied hydrogen production.

Integrated optimization of urban rail transit line planning, timetabling and rolling stock scheduling.

Urban rail transit train operation plan is a comprehensive production plan encompassing line planning, timetabling, and rolling stock scheduling. In order to solve the problem of infeasibility of the line plan and timetable because the number of rolling stocks could be only precisely considered in the rolling stock scheduling. An integrated optimization solution is proposed which considers the line plan, timetable, and rolling stock schedule. Candidate service routes are generated according to the layout of the turn-back stations. Considering the constraints of operation and passenger flow demand, an integer nonlinear programming model is established to minimize the cost of operation and passenger waiting time. The model complexity is analyzed and based on its decomposability a deterministic search algorithm is designed. Taking Chongqing Metro Line 3 in China as an example to verify the effectiveness of the proposed model and algorithm. Compared with the train operation plan based on manual experience and compiled by stages, the integrated optimization model can better improve the quality of train operation plan.

Ten questions concerning data-driven modelling and forecasting of operational energy demand at building and urban scale

Buildings account for over a third of end energy demand in many countries worldwide. Modelling this demand accurately marks the first step in producing forecasts that can help optimize energy efficiency as well as ensure stable grid operation, a growing concern with the electrification of heating and transportation demand and proliferation of renewable energy sources. These changes, for instance through large scale deployment of rooftop solar PV systems also mean that urban electricity demand is in a constant state of flux. To address these issues, a very large number of research papers have appeared in recent literature which propose or test different building and urban energy demand or load forecasting techniques, often with conflicting results. Meanwhile, in the same period, the broader field of forecasting has also witnessed tremendous development due to greater data availability, growth in computing power, and algorithmic innovations. As a result, there is little clarity in the energy demand forecasting field on best practices, especially in relation to the creation, evaluation, and utilization of these forecast models. This ten questions paper addresses this shortcoming and provides answers to the most important questions that researchers and practitioners alike need to ask themselves before creating their own demand forecaster, be it at the building or urban level. In addition to summarizing current best practices, the paper also provides an overview of some of the most important challenges related to energy demand forecasting and a principled framework to address them. Additionally, two companion notebooks provide an in-depth tutorial form introduction to load forecasting at both building and urban scale.

Nonlinear Response and Crosstalk of Electrically Driven Silicon Spin Qubits

Frequency multiplexing of operations is an attractive strategy to control multiple qubits simultaneously in a spin-based quantum processor with relatively few control lines. However, high-fidelity operation demands good spectral addressability and noncontextual spin dynamics. The authors explore an unexpected crosstalk mechanism, in which the Rabi frequency of one spin changes markedly depending on the simultaneous operation of another. They also connect this behavior to another surprising feature: the nonlinear scaling of Rabi frequency with resonant driving amplitude. These results provide insight into the challenges that such state-of-the-art control methods will face.

On-demand contactless programming of nonlinear elastic moduli in hard magnetic soft beam based broadband active lattice materials

Engineered honeycomb lattice materials with high specific strength and stiffness along with the advantage of programmable direction-dependent mechanical tailorability are being increasingly adopted for various advanced multifunctional applications. To use these artificial microstructures with unprecedented mechanical properties in the design of different application-specific structures, it is essential to investigate the effective elastic moduli and their dependence on the microstructural geometry and the physics of deformation at the elementary level. While it is possible to have a wide range of effective mechanical properties based on their designed microstructural geometry, most of the recent advancements in this field lead to passive mechanical properties, meaning it is not possible to actively modulate the lattice-level properties after they are manufactured. Thus the on-demand control of mechanical properties is lacking, which is crucial for a range of multi-functional applications in advanced structural systems. To address this issue, we propose a new class of lattice materials wherein the beam-level multi-physical deformation behavior can be exploited as a function of external stimuli like magnetic field by considering hard magnetic soft beams. More interestingly, effective property modulation at the lattice level would be contactless without the necessity of having a complex network of electrical circuits embedded within the microstructure. We have developed a semi-analytical model for the nonlinear effective elastic properties of such programmable lattice materials under large deformation, wherein the mechanical properties can be modulated in an expanded design space of microstructural geometry and magnetic field. The numerical results show that the effective properties can be actively modulated as a function of the magnetic field covering a wide range (including programmable state transition with on-demand positive and negative values), leading to the behavior of soft polymer to stiff metals in a single lattice microstructure according to operational demands.

A large scale artificial dataset to evaluate the impact of on-board monitoring set-ups on the Heat Transfer Coefficient assessment

At the current state, the majority of residential buildings are underperforming in terms of energy. To assess the current state of the building sector and bridge the gap between the designed and operative energy demand, quantifying the as-built envelope behaviour is essential. For this purpose the Heat Transfer Coefficient is used as a stationary performance indicator, however, prevailing assessment methods are impractical as they are performed on individual buildings. To extend the assessment range to urban scale statistics-based modelling techniques can be applied to limited and on-board collected data. In this step, where the accuracy of statistical methods and different input scenarios are investigated, simulated data is more suitable since there is no influence of measurement inaccuracy and the expected outcome is known. As part of this research, a comprehensive dataset to assess the HTC estimation methodology is created. The artificial dataset is generated using urban building energy models representative of the Belgian residential building stock. The generated artificial datasets resemble ideal measurement campaigns where inputs can be systematically selected which supports the aim of determining the impact of available monitoring setups. In this work, black-box AutoRegressive with eXogenous input statistical models were applied and the results show that, considering the assumed modelling limitations, with ideal monitoring setups 85% of the estimates fall within 10% of the target.

Optimal Rebalancing Strategy for Shared e-Scooter Using Genetic Algorithm

Shared e-scooters are provided as a free-floating service that can be freely rented and returned within the service area. Although this has a positive effect in terms of convenience for users of shared e-scooters, it is creating new urban problems, such as undermining the aesthetics of the city and obstructing the passage of pedestrians. Therefore, this study developed an optimal rebalancing algorithm to mitigate these problems and proposed an efficient operation plan. Complete relocation was performed to match the demand and supply for an efficient operation by reducing the unnecessary oversupply of shared e-scooters. The optimal rebalancing algorithm that reflects the attributes of e-scooters was developed through genetic algorithms and subsequently applied to actually used cases. The results indicate that when 20% of the potential demand was considered, an optimal solution could be derived with two relocation vehicles; however, when the potential demand was not considered, three relocation vehicles were required. Therefore, it is anticipated that the results of this study can serve as basic data for solving various urban problems caused by the recent rapid increase in the use of shared e-scooters.