Critical Operational Issues Research Articles

Corporate governance and financial performance: the case of English NHS hospitals

PurposeHospitals’ corporate governance (CG) mechanisms oversee critical operational issues and evaluate the outcomes. This paper investigates the impact of CG (i.e. board size, board independence, board expertise, board meetings, board gender diversity, CEO gender, and academic directors) on the financial performance of English National Health Service (NHS) hospitals and separately by hospital type (i.e. trusts and foundation trusts).Design/methodology/approachThe sample includes 128 NHS hospitals. The data were collected through document analysis and archival work from annual hospital reports from 2014 to 2018.FindingsThe findings indicate that board expertise, board meetings, board diversity, CEO gender, and academic directors significantly and negatively affect NHS hospitals’ financial performance. For NHS trusts, the results reveal that board expertise, board diversity, and CEO gender have a significant negative effect, while for NHS foundation trusts, only CEO gender has a significant negative impact.Originality/valueOverall, this study contributes to the literature on the healthcare system. It holds significant practical implications for hospital governance and has important implications for theories.

Empirical and simulated investigation of the solid waste reverse supply chain: A complex adaptive system perspective

Solid waste is increasing rapidly worldwide. In this study, the solid waste (household waste, construction and demolition waste and industrial waste) management systems are treated as reverse supply chain to analyze the critical operational issues based on complex adaptive system theory. At the single-layer, the complexity of the various nodes at a layer arises from rational decision-making and behavioral heterogeneity. The solid waste generation layer is employed as an example to investigate the complexity of node behavioral decisions. Regression analysis results reveal that both endogenous (Attitude, Subjective norm, and Perceived behavioral control) and exogenous factors (Economic incentive, Government supervision, Technical support) positively influence sorting behavior. The effect of Economic incentive (β=0.327P<0.001) and Attitude (β=0.249P<0.001) on sorting behavior are the largest. In the multi-layer system, different layers communicate with each other through the material and financial flows and have cross-layer impacts. An agent-based model is developed to investigate the multi-layer feedforward influence mechanism of changes in key layers (e.g., sorting rate, disposal rate) and the material and financial flows adaptive adjustment direction of the solid waste reverse supply chain. High rate of participation and accuracy of source sorting can shorten material flow paths and reduce storage and transportation costs. The increase in disposal rate encourages the transition of solid waste from backfill to resource utilization. This study provides a practice reference for solid waste reverse supply chain and related enterprises managers.

Assessing operational issues in a modular sewage treatment plant and providing remedies via comprehensive modeling and simulation through GPS-X

In this study, an existing but faulty modular sewage treatment plant (STP) with a capacity of 100 m3/day has been modeled and assessed using GPS-X software, combined with sensitivity analysis to confirm an underlying but critical operational issue of an STP. Currently, the STP shows <5 % ammonia removal at an average influent ammonia concentration of 50 mg/L, along with the problem of partial BOD removal. The treatment units comprise an equalization tank, two moving bed biofilm reactors (MBBRs) in series, a tube settler and a sand filtration unit. Sensitivity analysis helped decipher the most influential kinetics/stoichiometric parameters, which assisted in achieving a precise model calibration. Post calibration, the modified model was re-simulated for each constituent treatment unit based on the mass balance of four major output parameters viz. NH4-N, biochemical oxygen demand, dissolved oxygen and alkalinity. Real experimental/measured values spanning over 8 months were analyzed during the calibration phases (including both static and dynamic calibration phases). The calibrated GPS-X model was simulated using various input factors to find a possible remedial solution and understand the critical limitation of the existing plant. As a remedial measure, a pre-anoxic tank with an operational volume of 15 m3 and a recirculation ratio of 3 was proposed for the existing STP. A proper experimental design and statistical tools further helped achieve the most optimum and techno-economically feasible solution for an MBBR-based biological treatment unit. This helped effectively manage wastewater pollution in a modular treatment system.

Staff engagement through action learning enabling the practice of developing new services in a publicly funded university

Today, universities operate in an exceptionally challenging environment characterized by financial constraints and state‐imposed restrictions on critical strategic and operational issues. At the same time, they face rising student numbers and a more diverse student population. One way to address these challenges is through new service development (NSD). This paper examines how staff engagement through action learning can facilitate the development of new services in a complex organizational setting, such as a well‐established publicly funded university. En route, staff engagement in action learning enables the creation of capabilities for NSD. The empirical work involved four action learning projects carried out over a 15‐month period focused on the development of various service types. Applying action learning research, we describe and reflect on how different actors collaborated to develop new services and capabilities for NSD simultaneously. This study contributes a framework that identifies how action learning serves as an enabler for NSD and capability development, providing guidance for researchers and practitioners alike.

Multi-functional energy storage system for supporting solar PV plants and host power distribution system

Energy storage systems (ESS) will play a critical role in the ongoing development of the future electrical grid, especially as penetration of renewable energy generation increases. Since the costs of ESS are still high, it is imperative to research diverse control modes of ESS so as to use them in an effective manner, thereby offsetting their high costs. ESS technologies can diminish curtailment of renewable generators and provide much needed storage capabilities for supporting the grid, such as providing voltage regulation, relieving congestion, and improving power quality. This study develops six control modes for a battery ESS (BESS), namely, Current Limiting, Power Limiting, Load Leveling, Voltage Regulation, Power Factor Correction, and Simultaneous Real and Reactive Power Supply. The control modes are verified by simulation using a realistic utility 2.8-MW/5.6-MWh BESS and three solar PV plants connected to a power distribution grid. The study results demonstrate that the BESS functions properly in all the control modes. It can be used in all four quadrants of real and reactive power, i.e., it can provide any combination of real and reactive power amount within its rating for supporting the solar PV farms and the grid. The control modes enable effective operation of the BESS, which is a new tool to solve power system critical operational issues, thereby helping ensure the grid resilient, efficient, and reliable operation.

Mental Health among Italian Children and Adolescents during and after the SARS-CoV-2 Pandemic: A Professionals' Focus Group Study.

The SARS-CoV-2 pandemic had a negative impact on the mental health of children and adolescents. Eight focus groups and six individual hearings were conducted to gain insights from the perspectives of 97 Italian professionals from a variety of disciplines, including child and adolescent neuropsychiatrists, pediatricians, general practitioners, social workers, psychologists, teachers, school deans, non-governmental organizations, and a researcher. Urban and rural settings were represented. The present research has been promoted by the Italian Independent Authority for Children and Adolescents (Autorità Garante per l'Infanzia e l'Adolescenza, AGIA) in collaboration with the National Institute of Health (Istituto Superiore di Sanità, ISS) and the Ministry of Education and its scientific value has been supervised by a Scientific Committee. The results of the focus groups' discussions revealed increased vulnerability, with the onset of new mental health disorders in healthy individuals and those in a condition of disadvantage, migratory contexts, and with disabilities. The already critical pre-pandemic structural and operational issues of existing services have been exacerbated. In healthcare, the activation of telemedicine has been a great asset but at the same time has generated challenges and critical issues that are still unresolved. Professionals emphasized the need to pay special attention to planning integrated responses aimed at overcoming inequalities and fragmentation. The result of this initiative translates into a set of operational recommendations useful for guiding investments and policies directed toward the protection of the mental health of minors in the health, educational, and social spheres from the outset.

Video display terminal use and limitations according to italian legislative decree: occupational and forensic perspective.

In this paper, the authors conduct a review inherent in the use of video display units considering the laws currently in force in Italy, with emphasis on critical legislative and operational issues. Video Display Terminal (VDTs) are today an essential element in almost all work environments, from offices where they represent the fundamental work tool to production environments where they are indispensable for carrying out control functions (command stations, quantity management and flows, etc.) or for design work. The risk due to VDTs is one of the factors considered by the Italian Legislative Decree 81/08, so its assessment is part of the employer's obligations and at the same time requires health surveillance by the occupational physician. The new workstations have certainly not reduced visual postural demands, but they have changed them, opening the door to new disor-ders and imposing greater flexibility on the activity of the occupational physician, who often cannot limit himself to an annual inspection of the workplace. The aim of this work is to examine the current critical issues and future prospects of ergophthalmology.

Functional Rhythmic Chemical Systems Governed by pH‐Driven Kinetic Feedback

AbstractHydrogen ion autocatalytic reactions, especially in combination with an appropriate negative feedback process, show a wide range of dynamical phenomena, like clock behavior, bistability, oscillations, waves, and stationary patterns. The temporal or spatial variation of pH caused by these reactions is often significant enough to control the actual state (geometry, conformation, reactivity) or drive the mechanical motion of coupled pH‐sensitive physico‐chemical systems. These autonomous operating systems provide nonlinear chemistry's most reliable applications, where the hydrogen ion autocatalytic reactions act as engines. This review briefly summarizes the nonlinear dynamics of these reactions and the different approaches developed to properly couple the pH‐sensitive units (e. g., pH‐sensitive equilibria, gels, molecular machines, colloids). We also emphasize the feedback of the coupled processes on the dynamics of the hydrogen ion autocatalytic reactions since the way of coupling is a critical operational issue.

Parametric investigation of sand erosion rates in gas pipeline bends under typical industry conditions using simplified method

ABSTRACT The production and transport of sand from oil and gas wells into production and transport facilities results in flow assurance and structural problems. A critical operational issue is the erosion of oil and gas facilities by the suspended sand particles, particularly around flow diversions. This study investigated the effects of four key parameters, namely particle size, sand load, fluid velocity, and fluid density, on the rate of sand erosion in gas pipeline bends using DNV GL-RPO501 and Star CCM+ software package, a Computational Fluid Dynamics (CFD) tool developed by CD – adapco. Sand concentration and particle sizes both cause a linear increase in erosion rate. The particle sizes affected the location of maximum erosion. The single and mixture component gas densities showed an inverse linear and non-uniform relationship with erosion rate. The CFD models underpredicted erosion rates by about 90% compared to the experimental data. An exponential relation exists between the erosion rate and gas/sand velocity especially velocities above 10 m/s. The CFD method largely predicted more realistic values of erosion rate than the DNV GL-RPO501 due to some oversimplified assumptions made in the latter. The CFD tool however compared favorably with the DNV GL-RPO501 at high velocities. Both CFD and DNV GL-RPO501 models are recommended for erosion studies at higher fluid velocities, while the CFD modeling is better at lower velocities by incorporating drag and inertial forces which are important forces at low gas velocities. The particle and fluid velocity affected the sand erosion rate more than the other factors considered. However, future studies should consider modeling erosion rates under transient conditions and investigate the effects of various turbulence models. Different sand mixtures with various particle sizes and other gases such as CO2 should be considered.

Modelling of the photo-Fenton process with flexible hydrogen peroxide dosage: Sensitivity analysis and experimental validation

The supply of hydrogen peroxide (H2O2) controlling the amount of highly oxidant hydroxyl radicals is the most critical operational issue for the photo-Fenton process. Accordingly, this study addresses the development of a model for photo-Fenton processes including a flexible H2O2 supply given as a function of time. The model is aimed at its future exploitation in treatment optimization and the determination of the optimal profile for H2O2 supply. The work has adopted a photo Fenton model previously reported that includes the inlet flow (fed-batch) and describes the system dynamics under a flexible dosage. Thus, model global sensitivity analysis (GSA) and parameter estimation were performed using Simulink® to examine the behavior of the model under flexible H2O2 dosage. GSA was carried out using partial rank correlation methods and the Latin hypercube sampling to assess to which extent variations of the model parameters affect each measured response (H2O2, total organic carbon, TOC, and dissolved oxygen, O2 –the experimentally available information). Hence, the model is discussed in regard of its hypothesis and chances for reducing its complexity. This resulted in the rejection of two reactions of the initial model. Next, a set of 12 kinetic, stoichiometric and operative parameters was estimated through the fitting of H2O2, TOC, and O2 profiles. Discussion on model fitting includes computational issues, the role of initial values for the estimation process, the goodness of fit criteria, and the sampling method. The model was fit to experimental data with assorted H2O2 supply profiles and validated, and Root Mean Square Error (RMSE) below 0.009 mM, 0.42 mM, and 0.127 mM were obtained for TOC, H2O2 and O2, respectively. Therefore, this work contributes a practical model aimed at providing model-based optimization for the H2O2 dosage profile of the photo-Fenton process.

Diagnose in der Modularen Produktion

This paper presents concepts of operator- and system-centered diagnostics as well as approaches for the implementation of standardized diagnostics in modular process units - prepared by the ZVEI/NAMUR working group 4.1.1. Availability is a critical issue in the operation of process plants. Maintenance should not signify a substantial cost driver. By combining a MTP-like and NOA-like diagnostic channels, the balance between the encapsulation in operation (via MTP) and the necessary transparency for efficient diagnostics (via NOA) can be handled. In this paper, insights of both channels are presented to allow for open discussions about these concepts.

Decision-Making Process for Photovoltaic Solar Energy Sector Development using Fuzzy Cognitive Map Technique

Photovoltaic Solar Energy (PSE) sector has sparked great interest from governments over the last decade towards diminution of world’s dependency to fossil fuels, greenhouse gas emissions reduction and global warming mitigation. Photovoltaic solar energy also holds a significant role in the transition to sustainable energy systems. These systems and their optimal exploitation require an effective supply chain management system, such as design of the network, collection, storage, or transportation of this energy resource, without disregarding a country’s certain socio-economic and political conditions. In Brazil, the adoption of photovoltaic solar energy has been motivated not only by the energy matrix diversification but also from the shortages, problems, and barriers that the Brazilian energy sector has faced, lately. However, PSE development is affected by various factors with high uncertainty, such as political, social, economic, and environmental, that include critical operational sustainability issues. Thus, an elaborate modelling of energy management and a well-structured decision support process are needed to enhance the performance efficiency of Brazilian PSE supply chain management. This study focuses on the investigation of certain factors and their influence on the development of the Brazilian PSE with the help of Fuzzy Cognitive Maps. Fuzzy Cognitive Map is an established methodology for scenario analysis and management in diverse domains, inheriting the advancements of fuzzy logic and neural networks. In this context, a semi-quantitative model was designed with the help of various stakeholders from the specific energy domain and three plausible scenarios were conducted in order to support a decision-making process on PSE sector development and the country’s economic potential. The outcome of this analysis reveals that the development of the PSE sector in Brazil is mainly affected by economic and political factors.

A Review of Power System Flexibility With High Penetration of Renewables

The notion of secure operation of power systems, with its present semantic, dates back to the last decade. Since then, tremendous research effort has investigated secure operation of the power system. Nevertheless, operators are still faced with security issues, with even larger uncertainty, however, caused by the integration of renewable energy sources (RES). The system's ability to cope with the volatility of RES and load becomes a critical issue in power system operation. This paper surveys the literature on the concepts of power system flexibility, indices of flexibility, and implementation of the concept of flexibility in power system security. The paper proceeds to review the origin of the reserve problem, the meaning of reserve, its technical classification and related economical aspects. The paper highlights the effect of renewables on these aspects, and suggests new research directions.

Strategic Planning of Urban Network Evacuation with Balanced Signal Control and Crosselimination Strategies

AbstractThis paper addresses a critical operational issue of optimally converting some signalized intersections in an evacuation network into crosselimination control points to improve system perfo...

Dynamic Data-Driven Combustor Design for Mitigation of Thermoacoustic Instabilities

A critical issue in design and operation of combustors in gas turbine engines is mitigation of thermoacoustic instabilities, because such instabilities may cause severe damage to the mechanical structure of the combustor. Hence, it is important to quantitatively assimilate the knowledge of the system conditions that would potentially lead to these instabilities. This technical brief proposes a dynamic data-driven technique for design of combustion systems by taking stability of pressure oscillations into consideration. Given appropriate experimental data at selected operating conditions, the proposed design methodology determines a mapping from a set of operating conditions to a set of quantified stability conditions for pressure oscillations. This mapping is then used as an extrapolation tool for predicting the system stability for other conditions for which experiments have not been conducted. Salient properties of the proposed design methodology are: (1) It is dynamic in the sense that no fixed model structure needs to be assumed, and a suboptimal model (under specified user-selected constraints) is identified for each operating condition. An information-theoretic measure is then used for performance comparison among different models of varying structures and/or parameters and (2) It quantifies a (statistical) confidence level in the estimate of system stability for an unobserved operating condition by using a Bayesian nonparametric technique. The proposed design methodology has been validated with experimental data of pressure time-series, acquired from a laboratory-scale lean-premixed swirl-stabilized combustor.

Fractal Analysis of pH Time-Series of an Anaerobic Digester for Cheese Whey Treatment

AbstractCheese whey is a byproduct of the cheese industry and contains high concentrations of organic matter. Anaerobic digestion (AD) technology is an attractive solution to whey disposal since it allows the reduction of organic matter and simultaneously generates energy via biogas. The biological degradation of cheese whey is characterized by an unstable operation. A critical operational issue in the AD treatment of cheese whey is the tendency of rapid acidification of the waste requiring robust monitoring and control systems for reliable and efficient operation. Recent studies show that techniques based on fractal analysis of time series can be used for the indirect monitoring of critical variables of AD process (i. e., COD, VFA and methane production) for agro-industrial wastewaters. In this work, the application of the fractal analysis of pH time series obtained from an up-flow digester for cheese whey treatment is presented. The results suggest that fractal analysis can be applied to the indirect monitoring of a representative and high strength dairy wastewater. Furthermore, although the complex phenomena underlying in pH in the AD of cheese whey, the fractal analysis can unveil correlations of fractal parameters with key process variables.

Challenges Caused by the Unmanned Aerial Vehicle in the Air Traffic Management

The increasing number of unmanned aerial vehicle poses new challenges in the aviation industry especially the air traffic control, which is responsible for the safe flight operations in the controlled airspaces. In order to protect the conventional aircraft a new operation environment has to be created, which guarantee the safe flying and the possibility of the fulfilment of the flight. In the article drone related safety and operational problems are highlighted. All issue connected to the coexistence of manned and unmanned aircrafts are critical, thus their management have significant importance.Spread and wide use of unmanned aerial vehicle traffic management systems (UTM) can manage the critical operational issues, but is has to be defined that what is the problem, what is the scope, what is the operational environment. Services and functions related to the operation of the UTM system are defined, which are necessary for the safe flying fulfilled by the unmanned vehicles.

Stability of Propane-air and oxyfuel diffusion flames in a swirl-stabilized combustor; an experimental study

Emission of greenhouse gases like CO2 is associated with global warming and ultimately climate change. Oxy-fuel combustion as a carbon capture technique is among the most widely recommended means of tackling CO2 emission. The use of oxygen/carbon dioxide (O2/CO2) mixture as oxidizer in place of air will result in distinct combustion characteristics. Flame blowout is one of such characteristics and is one of the critical operational issues in real combustion systems. In this study, blowout characteristics of air and oxyfuel combustion of propane in a non-premixed, swirl-stabilized combustor were studied. The effect of the equivalence ratio on flame blow off for three oxidizer mixtures (air, oxyfuel I, and oxyfuel II) was first studied. Furthermore, the effect of CO2 addition and swirl number on oxyfuel flame blowout was also studied. Results show that the propane–air flame transits from: attached flame - lifted flame - no flame regimes with the lifted flame regime occurring at a critical velocity ratio (ratio of fuel velocity to oxidizer velocity). The oxyfuel I and oxyfuel II flames, however, transit directly from attached flame to no flame regime at all firing rates below 4.5MW/m3 bar. This is due to the fact that oxyfuel I and oxyfuel II could not reach the critical velocity ratio for oxy-flames (Critical velocity ratio observed = 3) before flame blowout. We observed that the critical velocity ratio for propane oxyfuel combustion is six times more than that of propane–air combustion (about 0.5). At 5 MW firing rate, the amount of CO2 required in the oxidizer at the attached flame - lifted flame transition point decreases from 76% to 74% as the equivalence ratio decreases from 1 to 0.9. The velocity ratios at this operating condition are 3.1 and 3.2, respectively and are more than critical velocity ratio for propane oxyfuel combustion. This indicated that attached flame - lifted flame transition is strongly dependent on the critical velocity ratio irrespective of the equivalence ratio. Further studies showed that oxyfuel flames are more stable at stoichiometry conditions and swirl number of unity.

Systematic variation of membrane casting parameters to control the structure of thermo-responsive isoporous membranes

Fouling is a critical issue in membrane process operation as it greatly compromises the efficiency of the treatment processes. A promising approach to overcome this problem is the production of easy-to-clean membranes by incorporating stimuli-responsive pores. In this study, we fabricated thermo-responsive polystyrene-b-poly(N-isopropyl acrylamide) (PS-b-PNIPAM) block copolymer membranes using the self-assembly and non-solvent induced phase separation (SNIPS) method and systematically varied several membrane casting parameters, i.e. evaporation time, polymer concentration, solvent type and water content, to obtain nano- and isoporous membranes. Membranes with a disordered surface were obtained for PS selective solvents, whereas isoporous membranes were obtained when the block copolymers were dissolved in PNIPAM selective solvent mixtures. Using 1,4-dioxane/ tetrahydrofuran mixtures resulted in isoporous membranes for a large parameter space, indicating the robustness of structure formation in the PS-b-PNIPAM system. Permeability tests at various temperatures demonstrated fully reversible thermo-responsive behavior of the membranes.

Using an integrated model of care between an acute hospital and primary care in a transitional care unit to support patient flow and discharge home

Introduction: Hospitals have increasing numbers of emergency department attendances each year. We need to treat these patients more quickly and avoid emergency over-crowding thus allowing patients to flow freely through the acute hospital. Hospitals require timely and efficient discharge processes to achieve adequate patient flow. In a previous quality improvement project to reduce readmissions, we had highlighted the importance of supporting patients with complex discharge needs at the time of discharge. Achieving safe, timely and person-centred discharge from hospital to home is an important indicator of quality and a measure of effective integrated care. At a time when building new acute beds is not feasible innovative new ideas are required to attain this goal. Practice change: We planned and commissioned a new off-site 18-bedded transitional care unit (TCU). The nursing and therapy team of the TCU are part of our acute hospital nursing service. The medical model is a unique hybrid with a local general practice providing day-to-day medical input supported by the consultant geriatricians from the acute hospital. Active daily discharge planning and creating links with community is a primary goal of the TCU. There is a weekly multidisciplinary meeting including the GPs and geriatricians with the unit team. Aim: Our TCU was developed to support the smooth flow of patients with complex discharge needs from the acute hospital back to home in a safe and timely manner. The goal of the TCU is to reduce the patients’ stay in acute care and provide effective discharge planning. Targeted population: The TCU is designed to care for patients who no longer require active acute hospital facilities but are not yet ready to discharge directly home. Patients requiring multidisciplinary assessment, a short reablement programme or social care set-up before discharge are suitable. All patients come directly from our acute hospital. Highlights: The TCU opened in September 2016 after nine-months of planning and refurbishment. The TCU is now admitting about 50 patients per month with an average length of stay of 9.1 days. The identification of appropriate patients for the TCU is sustained by a daily “discharge support meeting” and senior staff assessment in the acute hospital. The TCU has developed increasingly close links with other community discharge support services Discussion & Conclusions: Our TCU has been successfully opened and is achieving its goals. Successful discharge involves far more than a move from hospital to home. Appropriate discharge planning emphasises patient support and communication. Success and sustainability of the TCU is possible with a dynamic nursing and therapy team. Acute hospital identification and assessment of appropriate patients is vital for the TCU. The hybrid model of medical care has been a positive innovation that could be replicated elsewhere. Lessons learned: Social & non-clinical problems are often involved in complex discharges Discharge planning is not started early enough in acute hospitals Communication and information transfer between acute wards and TCU is critical Complex operational issues emerge is organising and running an off-site unit