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Introduction: Intra-abdominal cystic formations represent heterogeneous pathologies with varied localization and clinical manifestation. The first challenge of a giant intra-abdominal cystic lesion is identifying the organ of origin. The clinical presentation of intra-abdominal cystic lesions varies from acute manifestations to non-specific symptoms or accidental discovery. Case presentation: A 2-year-old girl presents to the emergency unit with a fever of 38.5 Celsius, loss of appetite, and apathy. The investigations showed a gigantic intra-abdominal mass whose organ belonging could not be specified. Postoperatively, a giant mesenteric lymphangioma was evident, which was completely excised. Discussion: Giant cystic formations modify the anatomical reports and become space-replacing formations, and the starting point is even more challenging to assess preoperatively. Nevertheless, the careful evaluation of the characteristics of the formation, the effect on the adjacent organs, the age of the patient, and the clinical picture can provide elements of differential diagnosis. The stated purpose of this work is to systematize intra-abdominal lesions according to the organ of origin and to make the preoperative diagnosis of an intra-abdominal cystic lesion in the pediatric patient easy to perform starting from the presented case. [ABSTRACT FROM AUTHOR]

Diamond–Blackfan anemia is a rare (6–7 million live births), inherited condition manifesting as severe anemia due to the impaired bone marrow production of red blood cells. We present the unusual case of a six month old infant with a de novo mutation of the RPS19 gene causing Diamond–Blackfan anemia who additionally suffers from severe sinus bradycardia. The infant was diagnosed with this condition at the age of four months; at the age of 6 months, she presents with severe anemia causing hypoxia which, in turn, caused severe dyspnea and polypnea, which had mixed causes (hypoxic and infectious) as the child was febrile. After correction of the overlapping diarrhea, metabolic acidosis, and severe anemia (hemoglobin < 3 g/dL), she developed severe persistent sinus bradycardia immediately after mild sedation (before central venous catheter insertion), not attributable to any of the more frequent causes, with a heart rate as low as 49 beats/min on 24 h Holter monitoring, less than the first percentile for age, but with a regular QT interval and no arrhythmia. The echocardiogram was unremarkable, showing a small interatrial communication (patent foramen ovale with left-to-right shunting), mild left ventricular hypertrophy, normal systolic and diastolic function, and mild tricuspid regurgitation. After red cell transfusion and appropriate antibiotic and supportive treatment, the child's general condition improved dramatically but the sinus bradycardia persisted. We consider this a case of well-tolerated sinus bradycardia and foresee a good cardiologic prognosis, while the hematologic prognosis remains determined by future corticoid response, treatment-related complications and risk of leukemia. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive overview of the most approached heuristic optimization techniques of water distribution networks (WDNs) focusing on their optimal design. A single- and multi-objective optimization problem is generally formulated, and the main optimization objectives, decision variables and constraints for the design, rehabilitation and operation of WDNs are synthesized and discussed. Additionally, the main heuristic methods are briefly described and classified. Finally, literature pertaining to the heuristic optimization models of WDNs is overviewed and in conclusion the advantages and disadvantages of the heuristic techniques used for designing WDNs are discussed along with some recommendations for future research directions. [ABSTRACT FROM AUTHOR]

This article presents a complex and exhaustive review of the integration of renewable energy sources (RES) (specifically solar, geothermal, and hydraulic energies and heat pumps (HPs)) and the improvement of water pumping in district heating systems (DHSs) focused on low-temperature systems, to increase energy efficiency and environmental protection. For this aim, the main components of a DHS and the primary RES with applications in DHSs were described briefly. Finally, several case studies regarding the DHS in Timisoara, Romania, were analysed. Thus, by integrating water source HP (WSHP) systems in cooperation with solar thermal and photovoltaic (PV) collectors and reducing the supply temperature from 110 °C to 30 °C in DHS, which supplies the water radiators to consumers in a district of this city in a 58/40 °C regime of temperatures and produces domestic hot water (DHW) required by consumers at 52 °C, a thermal energy saving of 75%, a reduction in heat losses on the transmission network of 90% and a diminution of CO2 emissions of 77% were obtained. Installed PV panels generate 1160 MWh/year of electricity that is utilised to balance the electricity consumption of HP systems. Additionally, mounting pumps as turbines (PATs) for the recovery of excess hydraulic energy in the entire heating network resulted in electricity production of 378 MW, and the variable frequency drive's (VFD) method for speed control for a heating station pump resulted in roughly 38% more energy savings than the throttle control valve technique. [ABSTRACT FROM AUTHOR]

Water distribution networks (WDNs) are systems of water distribution used in urban centers and industrial processes that require efficient design and operation, which may be achieved through effective application of optimization methods. This article provides a comprehensive, systematic overview of the most approached methods for numerical optimization and their application to WDN design and operation. The main optimization methods are briefly discussed. Additionally, a single- and multiobjective optimization problem is generally formulated, and the main objectives, decision variables, and constraints for the design, rehabilitation, and operation of WDNs are summarized and explained. Finally, literature pertaining to the deterministic and heuristic optimization models of WDNs is overviewed and categorized and the advantages and disadvantages of these methods in this domain are included, along with some directions for further researches. The author concluded that further research in heuristics should focus on hybrid methods and hyperheuristic techniques for optimizing WDNs, and in addition to the traditional WDN steady-state optimization, it is advisable to address more sustainably the transient design optimization of these networks. [ABSTRACT FROM AUTHOR]

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Summary: This article provides an extensive survey on the modelling and optimisation of district heating systems (DHSs) focused on the heat distribution network. For this purpose, the major components of a DHS have been described and discussed, and their modelling has been briefly reviewed, including numerical simulation models for heat sources, end‐users, and especially the distribution network. The main deterministic and heuristic optimisation techniques are briefly described. Additionally, a single‐objective and multiobjective optimisation problem is generally formulated, and the main optimisation criteria for the design and operation of the distribution network are synthesised and analysed. The state of the art in DHS optimisation has been also reviewed and categorised. Finally, some recommendations for future developments were included. [ABSTRACT FROM AUTHOR]

Summary Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used later for heating and cooling applications and for power generation. TES has recently attracted increasing interest to thermal applications such as space and water heating, waste heat utilisation, cooling, and air conditioning. Phase change materials (PCMs) used for the storage of thermal energy as latent heat are special types of advanced materials that substantially contribute to the efficient use and conservation of waste heat and solar energy. This paper provides a comprehensive review on the development of latent heat storage (LHS) systems focused on heat transfer and enhancement techniques employed in PCMs to effectively charge and discharge latent heat energy, and the formulation of the phase change problem. The main categories of PCMs are classified and briefly described, and heat transfer enhancement technologies, namely dispersion of low‐density materials, use of porous materials, metal matrices and encapsulation, incorporation of extended surfaces and fins, utilisation of heat pipes, cascaded storage, and direct heat transfer techniques, are also discussed in detail. Additionally, a two‐dimensional heat transfer simulation model of an LHS system is developed using the control volume technique to solve the phase change problem. Furthermore, a three‐dimensional numerical simulation model of an LHS is built to investigate the quasi‐steady state and transient heat transfer in PCMs. Finally, several future research directions are provided. Development of latent heat storage (LHS) systems focused on heat transfer and enhancement techniques used in phase change materials (PCMs) is reviewedThe main categories of PCMs are classified, and its characteristic properties are briefly describedHeat transfer enhancement technologies are also discussed in detailA numerical simulation model of two‐dimensional heat transfer and another with three dimensions for the LHS are includedSeveral future research directions are provided [ABSTRACT FROM AUTHOR]

Summary: The negative environmental impacts of burning fossil fuels have forced the energy research community seriously to consider renewable sources, such as naturally available solar energy. This paper provides an overview of solar thermoelectric (TE) cooling systems. Thus, this review presents the details referring to TE cooling parameters and formulations of the performance indicators and focuses on the development of TE cooling systems in recent decade with particular attention on advances in materials and modeling and design approaches. Additionally, the TE cooling applications have been also reviewed in aspects of electronic cooling, domestic refrigeration, air conditioning, and power generation. Finally, the possibility of solar TE cooling technologies application in “nearly zero” energy buildings is briefly discussed, and some future research directions are included. This research shows that TE cooling systems have advantages over conventional cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no working fluid, being powered by direct current, and easily switching between cooling and heating modes. [ABSTRACT FROM AUTHOR]

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation. TES systems are used particularly in buildings and in industrial processes. This paper is focused on TES technologies that provide a way of valorizing solar heat and reducing the energy demand of buildings. The principles of several energy storage methods and calculation of storage capacities are described. Sensible heat storage technologies, including water tank, underground, and packed-bed storage methods, are briefly reviewed. Additionally, latent-heat storage systems associated with phase-change materials for use in solar heating/cooling of buildings, solar water heating, heat-pump systems, and concentrating solar power plants as well as thermo-chemical storage are discussed. Finally, cool thermal energy storage is also briefly reviewed and outstanding information on the performance and costs of TES systems are included. [ABSTRACT FROM AUTHOR]

The dual reciprocity method (DRM) is a highly efficient numerical method of transforming domain integrals arising from the non-homogeneous term of the Poisson equation into equivalent boundary integrals. In this paper, the velocity and temperature fields of laminar forced heat convection in a concentric annular tube, with constant heat flux boundary conditions, have been studied using numerical simulations. The DRM has been used to solve the governing equation, which is expressed in the form of a Poisson equation. A test problem is employed to verify the DRM solutions with different boundary element discretizations and numbers of internal points. The results of the numerical simulations are discussed and compared with exact analytical solutions. Good agreement between the numerical results and exact solutions is evident, as the maximum relative errors are less than 5% to 6%, and the R2-values are greater than 0.999 in all cases. These results confirm the effectiveness and accuracy of the proposed numerical model, which is based on the DRM. [ABSTRACT FROM AUTHOR]

Energy use in water supply systems represents a significant portion of the global energy consumption. The electricity consumption due to the water pumping represents the highest proportion of the energy costs in these systems. This paper presents several comparative studies of energy efficiency in water distribution systems considering distinct configurations of the networks and also considers implementation of the variable-speed pumps. The main objective of this study is the energy optimisation of urban systems using optimal network configurations that reduce energy consumption and improve energy efficiency. The paper describes in detail four strategies for improving energy efficiency of water pumping: control systems to vary pump speed drive according to water demand, pumped storage tanks, intermediary pumping stations integrated in the network, and elevated storage tanks floating on the system. The improving energy efficiency of water pumping is briefly reviewed providing a representative real case study. In addition, a different approach for the hydraulic analysis of the networks and the determination of the optimal location of a pumped storage tank is provided. Finally, this study compares the results of the application of four water supply strategies to a real case in Romania. The results indicate high potential operating costs savings. [ABSTRACT FROM AUTHOR]

This paper approaches the optimisation of looped water distribution networks supplied from one or more sources, according to demand variation. The pipe networks have concentrated outflows or uniform outflow along the length of each pipe. An optimisation model coupled with a computational iterative procedure of optimal discharges through pipes is developed on the basis of linear programming for the design of new or partially extended water distribution networks. The optimum solution obtained by this model consists of one or two pipe segments of different discrete sizes between each pair of nodes. The improved linear optimisation model guarantees a high reliability. Also, it is possible to take into account the network pipes with variable discharge on route. Additionally, the paper compares the linear optimisation model to some others, such as the classic model of economical velocities, the Moshnin model and a nonlinear model. This shows a good performance of the proposed model. [ABSTRACT FROM PUBLISHER]

A ground-coupled heat pump (GCHP) system used to provide the space heating for an office room is a renewable, high performance technology. This paper discusses vapour compression-based HP systems, briefly describing the thermodynamic cycle calculations, as well as the coefficient of performance (COP) and CO2 emissions of a HP with an electro-compressor and compares different heating systems in terms of energy consumption, thermal comfort and environmental impact. It is focused on an experimental study performed to test the energy efficiency of the radiator or radiant floor heating system for an office room connected to a GCHP. The main performance parameters (COP and CO2 emissions) are obtained for one month of operation of the GCHP system, and a comparative analysis of these parameters is presented. Additionally, two numerical simulation models of useful thermal energy and the system COP in heating mode are developed using the Transient Systems Simulation (TRNSYS) software. Finally, the simulations obtained from TRNSYS software are analysed and compared to the experimental data, showing good agreement and thus validating the simulation models. [ABSTRACT FROM AUTHOR]

The ingestion of foreign bodies is a worldwide pediatric pathology. We assessed the clinical, endoscopic, and therapeutic aspects of this condition in a pediatric gastroenterology unit. We reviewed 61 patients (median age of 3.25 ± 4.7 years). The most frequently ingested objects were coins (26.23%), unidentified metal objects (13.11%), bones (8.19%), batteries, and buttons (6.55%). The clinical features we encountered included abdominal pain (55.73%), vomiting (34.42%), and asymptomatic children (29.5%). Routine X-ray examination enabled finding the foreign body in 42 of the cases. An esophagogastroduodenoscopy was performed within 24–72 hours. 25 cases resulted in a negative endoscopy (40.98%), 19 objects (31.14%) were removed using a polypectomy snare, and extraction failure occurred in 17 patients (27.86%). 28 foreign bodies were passed without incidents; in 14 cases, the swallowed objects were never found. In one case, a battery was stuck in the esophageal folds and led to tracheal-esophageal fistula and bronchopneumonia and later to esophageal stenosis. We report a large proportion of foreign bodies that could not be identified or removed due to lack of early endoscopy and poor technical settings. Batteries and sharp objects lead to severe complications and preschool-age children are at high risk for such events. [ABSTRACT FROM AUTHOR]

In district heating stations, the heat carrier is circulated between the energy source and consumers by a pumping system. Fluid handling systems, such as pumping systems, are responsible for a significant portion of the total electrical energy use. Significant opportunities exist to reduce pumping energy through smart design, retrofitting, and operating practices. Most existing systems requiring flow control make use of bypass lines, throttling valves or pump speed adjustments. The most efficient of these options is pump speed control. One of the issues in using variable-speed pumping systems, however, is the total efficiency of the electric motor/pump arrangement under a given operating condition. This paper provides a comprehensive discussion about pump control in heating stations and analyzes the energy efficiency of flow control methods. Specific attention is also given to the selection of motor types, sizing and pump duty cycle. A comparative energy analysis is performed on the hot water discharge adjustment using throttling control valves and variable-speed drives in a district heating station constructed in Romania. To correlate the pumped flow rate with the heat demand and to ensure the necessary pressure using minimum energy, an automatic system has been designed. The performances of these control methods are evaluated in two practical applications. The results show that approximately 20%-50% of total pumping energy could be saved by using the optimal control method with variable-speed pumps. Additionally, some modernization solutions to reduce the environmental impact of heating stations are described. [ABSTRACT FROM AUTHOR]