bluuebunny/crossref_metadata_2025 huggingface dataset:
Brood‐stock management and early hatchery rearing of Arctic charr (Salvelinus alpinus (Linnaeus))
Authors: Olk Tom Robin , Jeuthe Henrik , Thorarensen Helgi , Wollebæk Jens , Lydersen Espen
Published: December 2019

Arctic charr (Salvelinus alpinus (Linnaeus)) is a stenothermic cold‐water fish, which has been cultured in Northern Europe and North America since the 1980s. The industry has remained relatively small with an annual production between 6000 and 10 000 tonnes, and is still challenged by an unreliable offspring production. This review focuses on offspring production in Arctic charr aquaculture including holding conditions for brood‐stock, fertilisation and egg rearing until hatch. Brood‐stock requires low temperatures during summer (<12°C) with the optimum still unknown. The temperature maximum for egg incubation lies between 6 and 8°C. The composition of an optimal brood‐stock diet is debated regarding fatty acids. A demand for a freshwater‐based diet rich in omega‐6 fatty acids is indicated, but results remain inconclusive. Extensive knowledge has been gained on the timing of spawning and its manipulation through photoperiod, temperature and hormone treatments; spawning can be induced by short‐day photoperiod; and temperature drops to 5°C. Eggs are fertilised dry in ovarian fluid. Egg quality is highly variable and positively related to egg size and energy density. Contrary, little information is available on sperm quality and its impact on egg survival. There may also be profound differences between Arctic charr of stationary or anadromous origin regarding requirements for holding conditions of brood‐stock and their diet. However, these differences have received little attention, and direct comparative studies are in demand.
Authigenic carbonate burial in the Late Devonian–Early Mississippian Bakken Formation (Williston Basin, USA)
Authors: Davis Barnes Ben , Husson Jon M. , Peters Shanan E.
Published: December 2019

Late Devonian (Famennian) marine successions globally are typified by organic‐rich black shales deposited in anoxic and euxinic waters and the cessation of shelf carbonate sedimentation. This global ‘carbonate crisis’, known as the Hangenberg Event, coincides with a major extinction of reef‐building metazoans and perturbations to the global carbon cycle, evidenced by positive carbon‐isotope excursions of up to 4‰. It has been suggested that authigenic carbonate, formed as cements in sedimentary pore spaces during early burial diagenesis, is a significant mass fraction of the total global carbon burial flux, particularly during periods of low oxygen concentration. Because some authigenic carbonate could have originated from remineralization of organic carbon in sediments, it is possible for this reservoir to be isotopically depleted and thereby drive changes in the carbon isotopic composition of seawater. This study presents bulk isotopic and elemental analyses from fine‐grained siliciclastics of the Late Devonian–Early Mississippian Bakken Formation (Williston Basin, USA) to assess the volume and isotopic composition of carbonates in these sediments. Carbonate in the Bakken black shales occurs primarily as microscopic disseminated dolomite rhombs and calcite cements that, together, comprise a significant mass‐fraction (ca 9%). The elemental composition of the shales is indicative of a dynamic anoxic to sulphidic palaeoenvironment, likely supported by a fluctuating chemocline. Despite forming in an environment favourable to remineralization of organic matter and the precipitation of isotopically depleted authigenic carbonates, the majority of carbon isotope measurements of disseminated carbonate fall between −3‰ and +3‰, with systematically more depleted carbonates in the deeper‐water portions of the basin. Thus, although there is evidence for a significant total mass‐fraction of carbonate with contribution from remineralized organic matter, Bakken authigenic carbonates suggest that Famennian black shales are unlikely to be sufficiently 13C‐depleted relative to water column dissolved inorganic carbon to serve as a major lever on seawater isotopic composition.
Cutaneous vessel features of sensitive skin and its underlying functions
Authors: Jiang Wen‐cai , Zhang Hui , Xu Yafei , Jiang Changqing , Xu Yingying , Liu Wei , Tan Yimei
Published: December 2019

Background

Following the sufficient studies of the effects of skin barrier impairment and heightened neural reaction on sensitive skin (SS), many scholars have paid great attention to the roles of superficial microvasculature in SS.

Methods

By questionnaire survey, lactic acid sting test, and capsaicin test, eligible subjects were classified as normal skin, only lactic acid sting test positive (LASTP), only capsaicin test positive (CATP), and both positive (both LASTP and CATP). D‐OCT was used to photograph images for evaluating the cutaneous vessels features each group.

Results

Totally 137 subjects completed the study. Compared with LASTN group, the vascular vessels were closer to epidermis in LASTP group. Mesh and branching vessels were more popular in SS than normal skin. High blood vessel density was more prevalent in SS, while low density frequently presented in normal skin. The vascular depth had a closely negative correlation with face flushing and SSS, and vascular shapes had a good positive correlation with face flushing and SSB.

Conclusions

Our study indicates that there is a significant difference in vascular depth, shape, and density between SS and normal skin which is valuable to explore SS pathologic mechanism and to further investigate cutaneous microvasculature functions in SS.
Mid‐Miocene initiation of E‐W extension and recoupling of the Himalaya
Authors: Larson Kyle P. , Kellett Dawn A. , Cottle John M. , Camacho Alfredo , Brubacher Alex D.
Published: December 2019

The Tibetan plateau is host to numerous ~N‐S striking graben that have accommodated E‐W directed extension. The development of these structures has been interpreted to reflect a variety of different geological processes including plateau collapse, oroclinal bending or mid‐to‐lower crustal flow. New 40Ar/39Ar thermochronology and quartz c‐axis data from the Thakkhola graben of west‐central Nepal show that E‐W extension was ongoing at least locally by the early Miocene (ca. 17 Ma). Our new, and previously published chronologic information on the initiation of graben across the orogen shows that they typically developed immediately after cessation of the South Tibetan detachment system, a structural network that facilitated differential southward movement of the upper and middle crust. We interpret this fundamental switch in orogen kinematics to reflect recoupling of the middle and upper Himalayan crust such that the subsequent widespread flow of the mid‐to‐lower crust out of the system to the east forced brittle accommodation in the upper crust.
Of Polyps and Plenitude
Authors: Martin Nathan John
Published: December 2019

The second in a set of review articles treating Wye Allanbrook's posthumously published Secular Commedia (University of California Press, 2014). The reviews originated as a panel discussion organized by Edmund J. Goehring at the Mozart Society of America's 2018 meeting at the
University of Western Ontario.
Phase-Lags' Radial Variations Between Velocity, Shear Stress, and Pressure Gradient in Ultrahigh Frequency Pulsating Turbulent Flows
Authors: Jalil S. M.
Published: December 2019

Two-dimensional numerical simulations of wall-bounded turbulent pulsating flow driven by a sinusoidal velocity through a circular smooth tube are carried out. These computations for a Womersley number α ranged from 0.7 to 2069 and a dimensionless frequency ω+ ranged from 1.2×10−5 to 33.5. The aim of this study is to calculate the phase lag inside the unsteady turbulent boundary layer and across the tube. The phase lag of the velocity and shear stress with respect to the pressure gradient is deduced. Also, the instantaneous logarithmic layer and the turbulent parameters are analyzed. It is found that capturing the phase lag near the wall depends on resolving the Stokes layer thickness δst. At ultrahigh frequencies, the centerline velocity was delayed from the pressure gradient and wall shear stress by 45 deg and 90 deg, respectively. Consequently, the velocity and shear stress lagged behind the pressure gradient by 90 deg and 280 deg at the core of the tube, respectively, and by 45 deg at the wall. Thus, the trend of the radial phase lag increases toward the tubes center for ω+>0.06, which contrasts with that at low frequencies. When a reversed flow is caused by increasing the amplitude of the imposed oscillations, the phase lag is not affected noticeably by this increment. The radial phase lag is kept constant outside the oscillatory boundary layer at high frequencies because the radial gradient of the axial velocity has vanished.
Aeroelastic Response of Variable-Speed Stall-Controlled Wind Turbine Rotors
Authors: Jalal Sarah , Ponta Fernando , Umrigar Apurva
Published: December 2019

In this paper, we focus on the Variable-Speed (VS) stall control method, a relatively new idea, which offers a promising perspective for future applications. As with the classical Fixed-Speed (FS) stall method, the elimination of the pitch mechanism, lowers the capital cost and reduces maintenance expenses, while at the same time, allows for a more efficient and precise control of power production. We present an analysis focused on the aeroe-lastic dynamic response of wind turbine rotors operating on the Variable-Speed stall control method. We conducted a wide range of experiments to assess the effects of rapid variations on the rotor’s operational conditions, like sudden gusts. Various gust conditions were tested for different wind speeds, represented by pulses of different intensity, occurring suddenly in an otherwise constant wind regime. Results for the aeroelastic dynamics of the rotor’s response, and the frequency content of its vibrations, are reported and analyzed.
Thermodynamic and Performance Study of Solar Regenerative Organic Rankine Cycle System for Use in Residential Micro-Combined Heat and Power Generation
Authors: Yaïci Wahiba , Entchev Evgueniy
Published: December 2019

A continued increase in both energy demand and greenhouse gas emissions (GHGs) call for utilising energy sources effectively. In comparison with traditional energy set-ups, micro-combined heat and power (micro-CHP) generation is viewed as an effective alternative; the aforementioned system’s definite electrical and thermal generation may be attributed to an augmented energy efficiency, decreased capacity as well as GHGs percentage. In this regard, organic Rankine cycle (ORC) has gained increasing recognition as a system, which is capable for generating electrical power from solar-based, waste heat, or thermal energy sources of a lower quality, for instance, below 120 °C.

This study focuses on investigating a solar-based micro-CHP system’s performance for use in residential buildings through utilising a regenerative ORC. The analysis will focus on modelling and simulation as well as optimisation of operating condition of several working fluids (WFs) in ORC in order to use a heat source with low-temperature derived from solar thermal collectors for both heat and power generation.

A parametric study has been carried out in detail for analysing the effects of different WFs at varying temperatures and flowrates from hot and cold sources on system performance. Significant changes were revealed in the study’s outcomes regarding performance including efficiency as well as power obtained from the expander and generator, taking into account the different temperatures of hot and cold sources for each WF. Work extraction carried out by the expander and electrical power had a range suitable for residential building applications; this range was 0.5–5 kWe with up to 60% electrical isentropic efficiency and up to 8% cycle efficiency for 50–120 °C temperature from a hot source. The operation of WFs will occur in the hot source temperature range, allowing the usage of either solar flat plate or evacuated tube collectors.
Building Stock Inertia and Impacts on Energy Consumption and CO2 Emissions in Qatar
Authors: Kamal Athar , Al-Ghamdi Sami G. , Koc Muammer
Published: December 2019

Greenhouse gas emission reduction and the consequent decrease in the environmental impacts of fossil fuel can be achieved by cutting back on energy consumption in the building sector that consumes around 30% of total final energy around the globe. The building sector is a complex component of the modern economy and life and includes diverse types of structures, uses, and energy patterns. Such variability is a result of the way that buildings are designed, built, and used in addition to the variations of their materials, equipment, and users. From the start of the construction phase until their demolition, buildings involve energy consumption. A single building’s energy consumption pattern can be called its energy inertia, that is the way it consumes energy throughout its lifetime. Energy consumption also varies according to the age of the buildings. As a building gets older, its structure and equipment start losing their efficiency and often lead to increasing energy consumption over time. At any given time, the building sector is composed of structures of various ages. Some are under construction, others are recently built, some have lived to be mature and some quite old enough to be demolished. This complexity in the building sector creates a momentum against implementation of policies that reduce energy consumption. In this study, a system dynamic model is developed to perceive the temporal evolution of energy consumption and efficiency measures for the villa-type building stock in Qatar. This model tests energy efficiency policy measures such as renovation rates of 15 and 30 years, for buildings that are considered old, and also examines implementation of technology and building codes for new buildings. Results reveal savings of between 157 GWh and 1,275 GWh of electricity and reduction in CO2 emissions ranging from 77,000 tonnes to 602,000 tonnes.
A Non-Linear Auto-Regressive With Exogenous Inputs (NARX) Artificial Neural Network (ANN) Model for Building Thermal Load Prediction
Authors: Yu Byeongho , Kim Dongsu , Cho Heejin , Mago Pedro
Published: December 2019

Thermal load prediction is a key part of energy system management and control in buildings, and its accuracy plays a critical role to improve and maintain building energy performance and efficiency. To address this issue, various types of prediction model have been considered and studied, such as physics-based, statistical, and machine learning models. Physical models can be accurate but require extended lead time for model development. Statistical models are relatively simple to develop and require less computation time than other models, but they may not provide accurate results for complex energy systems with an intricate nonlinear dynamic behavior. This study proposes an Artificial Neural Network (ANN) model, one of the prevalent machine learning methods to predict building thermal load, combining with the concept of Non-linear Auto-Regression with Exogenous inputs (NARX). NARX-ANN prediction model is distinguished from typical ANN models due to the fact that the NARX concept can address nonlinear system behaviors effectively based on recurrent architectures and time indexing features. To examine the suitability and validity of NARX-ANN model for building thermal load prediction, a case study is carried out using field data of an academic campus building at Mississippi State University. Results show that the proposed NARX-ANN model can provide an accurate prediction performance and effectively address nonlinear system behaviors in the prediction.
Water Pollution Caused by Leather Industry: A Review
Authors: Hutton Magdeline , Shafahi Maryam
Published: December 2019

The volume of industrial wastewater is expected to double by 2025 resulting in an increase of contaminated freshwater resources. Comparing profits with the high contribution to environment strain per capita can serve to analyze the potential international market and pollutant reduction methods. This paper quantifies the process, water consumption, and pollution of the leather industry to assess its size and influence. The leather industry presents a unique case; one where its product is inherently strong, has multiple applications, and serves as a way of recycling for the meat industry. The wastewater of the leather industry includes Chromium and Nitrogen which are some of the most important concerns regarding the environmental pollution to water sources. The consumption for tanneries varies based on processing methods. Legislative pressure is applied to increase the management of wastewater and solid waste. Research regarding the leather industry is not as well developed as its dated tanning process, however it should be examined as an industry that provides ample opportunities for environmental, economic, and technological advancements.
Sustainable Biodiesel Production From Blends of Waste Cooking Oil and Microalgae Oil
Authors: Sugai Daniela Y. , Vargas José V. C. , Balmant Wellington , Dario Priscila P. , Martinez Leonardo C. , Taher Dhyogo M.
Published: December 2019

Waste cooking oil and microalgae oil could become alternative raw materials for biodiesel production in the global quest for energetic sustainability. However, the technical and economic viability of the biodiesel production process from these alternative sources has not been fully investigated yet, within the knowledge of the authors. Therefore, the main objective of this study is to carry out an exergetic and economical analysis of the biodiesel production process from blends of waste cooking oil and microalgae oil. Initially, the mass, energy and exergy balances of the process of the biodiesel production was conducted. Then, an optimization procedure was executed with the selected objective functions. The results showed that it is possible to optimize the process as a function of the ratio of destroyed exergy system by the amount of ester produced, generating a profit of $ 29.50 per second, for an ratio of oil/ethanol of 3.7/1. In conclusion, the proposed model can also be used in the future for performing the exergoeconomic optimization of biodiesel production processes from blends of waste cooking oil and microalgae oil, aiming at achieving process sustainability.
Clean Energy From Municipal Solid Waste (MSW)
Authors: Galante Renan M. , Vargas Jose V. C. , Balmant Wellington , Ordonez Juan C. , Mariano Andre B.
Published: December 2019

The global energy demand has increased at a very large rate, and in parallel, the Municipal Solid Waste (MSW) has also increased, both posing enormous technological challenges to world sustainable growth. Therefore, in order to contribute with concrete alternatives to face such quest for sustainability, this work presents an analysis of an integrated power plant fired by municipal solid waste that uses a biological filter for the combustion emissions fixation. The facility located in the Sustainable Energy Research & Development Center (NPDEAS) at Federal University of Parana is taken as a case study to analyze the process of technical and economic viability. For that, an exergoeconomic optimization model of the waste-to-energy power plant that generates electricity and produces microalgae biomass is utilized. An incineration furnace, which has a 50 kg/h capacity, heats the flue gas above 900°C and provides energy for a 15 kW water-vapor Rankine cycle. A set of heat exchangers preheats the intake air for combustion and provides warm utility water to other processes in the plant, which assures that the CO2 rich flue gas can be airlifted to the microalgae cultivation photobioreactors (PBR) at a low temperature, using a 9 m high mass transfer emissions fixation column. Five 12 m3 tubular photobioreactors are capable of supplying up to 30,000 kg/year of microalgae biomass with southern Brazil solar conditions of 1732 kWh/m2 per year. The results show that considering the incineration services, the integrated power plant could have a payback period as short as 1.35 years. In conclusion, the system provides a viable way to obtain clean energy by thermally treating MSW, together with microalgae biomass production that could be transformed in a large variety of valuable bioproducts (e.g., nutraceuticals, pharmaceuticals, animal feed, and food supplements).
Hydrodynamic Response of the Deep Turbine Installation-Floating Concept
Authors: Serret Jordi , Stratford Tim , Thies Philipp R. , Venugopal Vengatesan , Tezdogan Tahsin
Published: December 2019

Floating offshore wind turbine (FOWT) installations are progressing from the R&D stage to commercial installation projects. The prospective sites are situated in increasingly deeper water and further away from the shore. This paper presents the Deep Turbine Installation-Floating (DTI-F) concept, an innovative hybrid spar buoy-based FOWT capable of being able to raise and lower the tower and nacelle, which simplifies construction, installation, maintenance and decommissioning. The study is focused on the hydrodynamics of the moored floating system, and it is based on experimental and numerical modelling work. A 1:45 Froude scaled model of the DTI-F wind concept was tested using three different mooring configurations: i) three mooring lines, ii) four mooring lines, and iii) three mooring lines with a delta connection. Free decay and stiffness decay tests were carried out together with regular and irregular wave tests. The numerical study comprises diffraction (ANSYS AQWA) and time-domain modelling (OrcaFlex).

The experimental hydrostatic and hydrodynamic results are compared with the numerical simulations based on the as-built scale model. Considering the natural frequencies results obtained for the three mooring configurations, the three lines configuration without delta connection was selected as the most suitable design. The obtained results for the three mooring lines configuration show good agreement between the experiment and numerical simulations. The presented analysis of the design concept indicates a high degree of technical feasibility.
Induced Draft Fan Early Anomaly Identification Based on SIS Data Using Normal Behavior Model in Thermal Power Plant
Authors: Hu Di , Guo Sheng , Chen Gang , Zhang Cheng , Lv Dongzhen , Li Bing , Chen Qianming
Published: December 2019

In this work, a new idea was proposed that establishes normal behavior model (NBM) with multiple inputs and multiple outputs for each specific equipment based on Principle components analysis — Nonlinear autoregressive exogenous model (PCA-NARX) a kind of ANN. The operating parameters interested in condition monitoring are selected from SIS as an aggregation for a certain equipment, and the corresponding NBM is constructed based on the co-relation among parameters and the autocorrelation in each parameter. Each operating parameter can determine a reasonable range in real time by NBM, so it can detect abnormal operation parameters more quickly than the traditional fixed threshold method. Combining the historical operational data of the No. 1 induced draft fan of No. 3 generating unit in Shajiao C Power Plant in China, and the aggregation for induced draft fan covers 12 operating parameters interested in condition monitoring. This work used MATLAB to verify and analyze the proposed method. It is found that the NBM for induced draft fan early anomaly identification established in this work can achieve rapid response to the fault and give an alarm in the early stage of the fault. Moreover, the method can be easily applied to other mechanical equipment in thermal power plant and has good engineering application value.
Heat Transfer Enhancement of Phase Change Materials for Thermal Energy Storage Systems
Authors: Lim Celine S. L. , Weaver Ryan , Sobhansarbandi Sarvenaz
Published: December 2019

Solar water heaters (SWHs) are a well-established renewable energy technology that have been widely adopted around the world. The downfall of this technology is rooted in the inconsistency of solar intensity from day to night. In the recent studies, the application of energy storage materials such as phase change materials (PCMs) has attracted many attentions; however, PCM by itself may not be effective due to the poor heat transfer rate, low thermal diffusivity and thermal conductivity. This paper aims to explore the thermal performance of energy storage-transfer materials to be applied in conjunction with PCMs. The selected types of PCMs are paraffin waxes with melting point temperatures of 28–72°C. In the first analysis, silicone oil is selected as the heat transfer medium with high thermal stability. The melting point and specific heat capacity were measured by a modulated differential scanning calorimeter (MDSC). The obtained results show that silicone oil will lead to melting point depression of maximum 3°C in the PCMs. In the second analysis, the heat transfer enhancement by addition of nanoparticles has been investigated. The selected nanoparticles for this analysis are Aluminum Oxide (Al2O3) and Cupric Oxide (CuO). The obtained results from this study show thermal performance improvement of the PCMs which can be applied to different thermal energy storage systems, such as in the case of solar thermal collectors for the application in SWH technology.
Failure Analysis of SA-213 T91 HRSG Superheater Tube Weld
Authors: Jackson Peter S. , Fabricius Andreas , Wholey Alexandria
Published: December 2019

The root cause of a series of similar failures in SA-213 T91 Superheater tubes of an Heat Recovery Steam Generator (HRSG) is investigated using a combination of engineering analysis and review of process data. The HRSG at the Combined Cycle Gas Turbine (CCGT) Power Plant power plant in question had suffered from frequent tube-to-header fatigue failures over the past 10 years. Metallurgical analyses had never identified any sign of creep damage in, or near, any of the failure locations. Recently, the Gas Turbine (GT) exhaust gas flow pattern upstream of the SH tubes changed slightly. Subsequently there were a large number of HPSH tube to header failures (> 10) on one side of the gas duct. Metallurgical analysis showed that the tube-to-header welds failed by creep-fatigue damage; analyses of tubes from the left-hand side of the boiler did not show any signs of similar damage being present. Further investigation confirmed that the root cause was identified as higher temperatures resulting from small changes in the GT outlet flow pattern.
A Novel Combustion Air Preheating System in a Large-Scale Coal-Fired Power Unit
Authors: Chen Heng , Qi Zhen , Dai Lihao , Chen Qiao , Xu Gang , Pan Peiyuan
Published: December 2019

A novel hybrid system for combustion air heating, including flue gas cooling, air heating and heat regeneration has been proposed. In the reformative scheme, the air gains energy from four tubular heat exchangers and the flue gas releases heat in four tubular heat exchangers as well, instead of the rotary regenerative air preheater (APH) that is used in the conventional scheme. Consequently, the temperature differences between the fluids during heat transmission can be diminished, and the mixing of the hot-cold primary air and the severe leakages are avoided, which remarkably reduces the exergy destruction and enhances the thermal performance of the power unit. The new design was evaluated based on a 670 MW coal-fired supercritical power unit. The results show that the additional net power output of the power unit can reach 8.57 MW with a net efficiency promotion of 0.57 percentage points due to the novel configuration. And the energy saving mechanism of the proposed concept was revealed on grounds of the first and second laws of thermodynamics.
Design and Integration of a Renewable Energy Based Polygeneration System With Desalination for an Industrial Plant
Authors: Luciano De La Cruz Lucero Cynthia , Celis Cesar
Published: December 2019

Polygeneration improves energy efficiency and reduces both energy consumption and pollutant emissions compared to conventional generation technologies. A polygeneration system is a variation of a cogeneration system, in which more than two outputs, i.e., heat, power, cooling, water, energy or fuels, are accounted for. In particular, polygeneration systems integrating solar energy and water desalination represent promising technologies for energy production and water supply. They are therefore interesting options for coastal regions with a high solar potential, such as those located in southern Peru and northern Chile. Notice that most of the Peruvian and Chilean mining industry operations intensive in electricity and water consumption are located in these particular regions. Accordingly, this work focus on the design and integration of a polygeneration system producing industrial heating, cooling, electrical power and water for an industrial plant. In particular, the design procedure followed in this work involves integer linear programming modeling (MILP). The technical and economic feasibility of integrating renewable energy technologies, thermal energy storage, power and thermal exchange, absorption chillers, cogeneration heat engines and desalination technologies is particularly assessed. The polygeneration system integration carried out seeks to minimize the system total annual cost subject to CO2 emissions restrictions. Particular economic aspects accounted for include investment, maintenance and operating costs.
Investigating the Effects of Flue Gas Injection and Hot Water Distribution and Their Interaction on Natural Draft Wet Cooling Tower Performance
Authors: Eldredge Tom V. , Stapleton John M.
Published: December 2019

This paper utilizes numerical modeling to address the effects of two parameters on natural draft cooling tower performance, namely the radial hot water distribution and flue gas injection. Predictions show that cold water temperature leaving the tower can be slightly decreased by increasing the weighting of the radial hot water distribution towards the tower periphery. The injection of scrubbed flue gas into the tower chimney can have either a positive or a negative effect on tower cooling performance, depending on the temperature of the flue gas relative to the temperature of moist air in the chimney. The temperature of the scrubbed flue gas is the primary variable affecting cooling tower performance, associated with flue gas injection. This paper investigates using the radial distribution of hot water to optimize the tower cooling performance when injecting scrubbed flue gas into the chimney, both for conditions when the flue gas is warmer and cooler than the temperature of moist air in the chimney. Predictions with no flue gas injection show that optimizing hot water distribution produced 0.4 °C reduction in cooled water temperature. With relatively cold (32.2 °C) and relatively hot (65.6 °C) flue gas injection, optimizing hot water distribution produced slightly more than 0.2 °C reduction in cooled water temperature.
The Impact of the Converter on the Reliability of a Wind Turbine Generator
Authors: Singh Gopal , Lentijo Santiago , Sundaram Kalpathy
Published: December 2019

Temperature rise is one of the limiting factors in generator design. Bearings and windings failure are the two most prominent cause of generator failure in the wind turbine application. The generator is mostly converter-fed in the wind turbine application, and operation with converter brings specific challenges. Insulation of generator system should be designed in such a way to withstand these challenges. Two immediate problems with converter-fed wind generators are winding temperature rise due to harmonic losses and voltage peaks. Voltage peaks generated by converter can create a winding hotspot and eventually destroy the insulation system of generator winding, which leads to reducing the lifetime of the insulation system. Turbine availability study from a commercial point of view is presented. For selecting the winding insulation system, it is essential to know the environment generator is going to operate. Specific voltage peaks from different converter systems can damage windings insulation. Damage insulation brings the downtime of the turbine, which affects the LCOE and AEP of the wind turbine. The electrical voltage between motor terminals and ground can be generated due to the different converter output circuit, longer feeder cables (when converter being placed on the basement and not in the nacelle) on the and unfavorable grounding conditions. Paper discusses voltage peaks due to operation with converter and make a recommendation for the winding insulation system, for a particular case. A better selection procedure for a generator winding insulation system is recommended.
Sedentary Behavior and Chronic Disease: Mechanisms and Future Directions
Authors: Dempsey Paddy C. , Matthews Chuck E. , Dashti S. Ghazaleh , Doherty Aiden R. , Bergouignan Audrey , van Roekel Eline H. , Dunstan David W. , Wareham Nicholas J. , Yates Thomas E. , Wijndaele Katrien , Lynch Brigid M.
Published: December 2019

Background: Recent updates to physical activity guidelines highlight the importance of reducing sedentary time. However, at present, only general recommendations are possible (ie, “Sit less, move more”). There remains a need to investigate the strength, temporality, specificity, and dose–response nature of sedentary behavior associations with chronic disease, along with potential underlying mechanisms. Methods: Stemming from a recent research workshop organized by the Sedentary Behavior Council themed “Sedentary behaviour mechanisms—biological and behavioural pathways linking sitting to adverse health outcomes,” this paper (1) discusses existing challenges and scientific discussions within this advancing area of science, (2) highlights and discusses emerging areas of interest, and (3) points to potential future directions. Results: A brief knowledge update is provided, reflecting upon current and evolving thinking/discussions, and the rapid accumulation of new evidence linking sedentary behavior to chronic disease. Research “action points” are made at the end of each section—spanning from measurement systems and analytic methods, genetic epidemiology, causal mediation, and experimental studies to biological and behavioral determinants and mechanisms. Conclusion: A better understanding of whether and how sedentary behavior is causally related to chronic disease will allow for more meaningful conclusions in the future and assist in refining clinical and public health policies/recommendations.
The Hybrid Histidine Kinase HrmK Is an Early-Acting Factor in the Hormogonium Gene Regulatory Network
Authors: Zuniga Esthefani G. , Figueroa Natalie M. , Gonzalez Alfonso , Pantoja Adriana P. , Risser Douglas D.
Published: December 2019

Filamentous cyanobacteria are morphologically complex, with several representative species amenable to routine genetic manipulation, making them excellent model organisms for the study of development. Furthermore, two of the developmental alternatives, nitrogen-fixing heterocysts and motile hormogonia, are essential to establish nitrogen-fixing symbioses with plant partners. These symbioses are integral to global nitrogen cycles and could be artificially recreated with crop plants to serve as biofertilizers, but to achieve this goal, detailed understanding and manipulation of the hormogonium and heterocyst gene regulatory networks may be necessary. Here, using the model organism
Nostoc punctiforme
, we identify a previously uncharacterized hybrid histidine kinase that is confined to heterocyst-forming cyanobacteria as the earliest known participant in hormogonium development.
Endoplasmic Reticulum (ER) Reorganization and Intracellular Retention of CD58 Are Functionally Independent Properties of the Human Cytomegalovirus ER-Resident Glycoprotein UL148
Authors: Nguyen Christopher C. , Domma Anthony J. , Zhang Hongbo , Kamil Jeremy P.
Published: December 2019

In myriad examples, viral gene products cause striking effects on cells, such as activation of stress responses. It can be challenging to decipher how such effects contribute to the biological roles of the proteins. The HCMV glycoprotein UL148 retains CD58 within the ER, thereby preventing it from reaching the cell surface, where it functions to stimulate cell-mediated antiviral responses. Intriguingly, UL148 also triggers the formation of large, ER-derived membranous structures and activates the UPR, a set of signaling pathways involved in adaptation to ER stress. We demonstrate that the potential of UL148 to reorganize the ER and to retain CD58 are separable by mutagenesis and, possibly, by evolution, since chimpanzee cytomegalovirus UL148 retains CD58 but does not remodel the ER. Our findings imply that ER reorganization contributes to other roles of UL148, such as modulation of alternative viral glycoprotein complexes that govern the virus’ ability to infect different cell types.
Mucus Is a Key Factor in Neisseria meningitidis Commensalism
Authors: Callaghan Melanie M. , Dillard Joseph P.
Published: December 2019

The work presented by Audry et al. (M. Audry, C. Robbe-Masselot, J.-P. Barnier, B. Gachet, et al., mSphere 4:e00494-19, 2019,
https://doi.org/10.1128/mSphere.00494-19
) gives new insight into the interactions of
Neisseria meningitidis
and the human nasopharynx.
Progressive myeloneuropathy with symptomatic anaemia
Authors: Rohm Charlene L , Acree Sara , Lovett Louis
Published: December 2019

Hypocupremia is a rare and under-recognised cause of bone marrow dysplasia and myeloneuropathy. A 47-year-old Caucasian woman had progressive ascending peripheral neuropathy and gait ataxia over 3 months and fatigue, dyspnoea and unintentional weight loss over 8 months. She had profound macrocytic anaemia and neutropenia. Initial workup included normal serum vitamin B12. Bone marrow biopsy was suggestive of copper deficiency. Serum copper levels were later confirmed to be undetectable. The patient received oral copper repletion which resulted in complete normalisation of haematological abnormalities 16 weeks later. However, neurological deficits persisted. This case describes a delayed diagnosis of hypocupremia as initially suggested through invasive testing. Associating myeloneuropathy with cytopenia is imperative for accurate and prompt diagnosis of hypocupremia, which can be confirmed by serum analysis alone. Developing an accurate differential diagnosis can help prevent unnecessary procedures. Furthermore, initiating prompt copper repletion prevents further neurological impairment. Neurological deficits are often irreversible.
Primary cardiac lymphoma
Authors: Chia Alicia Xue Fen , Zhao Zitong , Lim See Lim
Published: December 2019

Primary cardiac lymphoma (PCL) is a rare neoplasm involving the heart, pericardium or both. Patients with PCL have a median survival of approximately 7 months based on literature. We report a unique case of a 63-year-old woman presenting with worsening exertional dyspnoea and symptoms of superior vena cava obstruction. Investigations revealed a large right atrial (RA) tumour with obstructive features. In the past, PCL was frequently diagnosed at postmortem but with modern imaging and biopsy techniques, this allows early diagnosis and treatment of this rapidly fatal disease. Our patient had a trans-jugular venous biopsy of the RA mass under trans-oesophageal echocardiography guidance. This confirmed the diagnosis of PCL. She subsequently completed seven cycles of chemotherapy and is currently in remission 20 months after diagnosis.
Management of a parturient with uncorrected tetralogy of Fallot in shock: an anesthetic challenge
Authors: Bellapukonda Snigdha , Roncall Bhim Raju , Mund Manisha
Published: December 2019

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. The survival of patients with uncorrected TOF till the fourth decade of life is rare (around 3%). Pregnancy in a patient with uncorrected TOF requires a multidisciplinary approach. A confluence of pregnancy, uncorrected TOF and shock is infrequent. The state of hypovolaemia and a decrease in systemic vascular resistance due to anaesthetic agents increase the right to left shunt. The decrease in pulmonary blood flow provokes a ‘hypercyanotic spell’. We report the successful management of 30-year-old pregnant (G3P2A2L0) with uncorrected TOF, presenting to the emergency department with incomplete abortion in shock.
Delay in the diagnosis of measles complicated by pneumonitis and appendicitis in a returning traveller
Authors: Laundy Nicholas C , Greig Julia M , Raza Mohammad , Mitchell Tamara
Published: December 2019

A 40-year-old British man presented to the emergency department for the second time in 10 days following a 2-week holiday in Thailand with malaise, bilateral conjunctivitis and a morbilliform rash. He had previously seen his general practitioner and ophthalmology and was diagnosed with conjunctivitis. We confirmed measles following RNA detection on a mouth swab. Four days after admission he developed abdominal pain and a CT abdomen demonstrated acute appendicitis with large appendicoliths. A perforated appendix was identified intraoperatively. Measles RNA was detected in the resected appendix. Preoperatively he developed hypoxia with right upper lobe changes seen on a CT pulmonary angiogram. Bronchoalveolar lavage performed in theatre isolated measles RNA at high level, consistent with measles pneumonitis. He required ventilatory support in the intensive care unit and was also treated with intravenous antibiotics. He made a complete recovery.
Sudden arrhythmia followed by bradycardia during sagittal split ramus osteotomy: trigeminocardiac reflex
Authors: Kim Hyunjee
Published: December 2019

Trigeminocardiac reflex (TCR) is a brainstem reflex triggered by the stimulation of any branch of the fifth cranial nerve along its course, presenting as a reduction in heart rate and blood pressure. Oculocardiac reflex is a well-known subtype of TCR. In the case reported here, remarkable arrhythmia followed by bradycardia occurred suddenly in a healthy patient undergoing orthognathic surgery. The heart rhythm recovered when the surgical manipulation ceased, but bradycardia was reproduced when the surgery resumed. This case of TCR is unique in that remarkable arrhythmia first appeared and led to bradycardia; accordingly, intravenous lidocaine and an anticholinergic agent were administered simultaneously instead of anticholinergic agents alone, and were protective. Although TCR rarely occurs during orthognathic surgery, clinicians should be aware of its possibility and able to judge and manage it promptly.
Job morale of physicians in low-income and middle-income countries: a systematic literature review of qualitative studies
Authors: Sabitova Alina , Sajun Sana Zehra , Nicholson Sandra , Mosler Franziska , Priebe Stefan
Published: December 2019

Objectives

To systematically review the available literature on physicians’ and dentists’ experiences influencing job motivation, job satisfaction, burnout, well-being and symptoms of depression as indicators of job morale in low-income and middle-income countries.

Design

The review was reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for studies evaluating outcomes of interest using qualitative methods. The framework method was used to analyse and integrate review findings.

Data sources

A primary search of electronic databases was performed by using a combination of search terms related to the following areas of interest: ‘morale’, ‘physicians and dentists’ and ‘low-income and middle-income countries’. A secondary search of the grey literature was conducted in addition to checking the reference list of included studies and review papers.

Results

Ten papers representing 10 different studies and involving 581 participants across seven low-income and middle-income countries met the inclusion criteria for the review. However, none of the studies focused on dentists’ experiences was included. An analytical framework including four main categories was developed: work environment (physical and social), rewards (financial, non-financial and social respect), work content (workload, nature of work, job security/stability and safety), managerial context (staffing levels, protocols and guidelines consistency and political interference). The job morale of physicians working in low-income and middle-income countries was mainly influenced by negative experiences. Increasing salaries, offering opportunities for career and professional development, improving the physical and social working environment, implementing clear professional guidelines and protocols and tackling healthcare staff shortage may influence physicians’ job morale positively.

Conclusions

There were a limited number of studies and a great degree of heterogeneity of evidence. Further research is recommended to assist in scrutinising context-specific issues and ways of addressing them to maximise their utility.

PROSPERO registration number

CRD42017082579.
Associations between metal constituents of ambient particulate matter and mortality in England: an ecological study
Authors: Lavigne Aurore , Freni Sterrantino Anna , Liverani Silvia , Blangiardo Marta , de Hoogh Kees , Molitor John , Hansell Anna
Published: December 2019

Objectives

To investigate long-term associations between metal components of particulate matter (PM) and mortality and lung cancer incidence.

Design

Small area (ecological) study.

Setting

Population living in all wards (~9000 individuals per ward) in the London and Oxford area of England, comprising 13.6 million individuals.

Exposure and outcome measures

We used land use regression models originally used in the Transport related Air Pollution and Health Impacts—Integrated Methodologies for Assessing Particulate Matter study to estimate exposure to copper, iron and zinc in ambient air PM. We examined associations of metal exposure with Office for National Statistics mortality data from cardiovascular disease (CVD) and respiratory causes and with lung cancer incidence during 2008–2011.

Results

There were 108 478 CVD deaths, 48 483 respiratory deaths and 24 849 incident cases of lung cancer in the study period and area. Using Poisson regression models adjusted for area-level deprivation, tobacco sales and ethnicity, we found associations between cardiovascular mortality and PM2.5copper with interdecile range (IDR 2.6–5.7 ng/m3) and IDR relative risk (RR) 1.005 (95%CI 1.001 to 1.009) and between respiratory mortality and PM10zinc (IDR 1135–153 ng/m3) and IDR RR 1.136 (95%CI 1.010 to 1.277). We did not find relevant associations for lung cancer incidence. Metal elements were highly correlated.

Conclusion

Our analysis showed small but not fully consistent adverse associations between mortality and particulate metal exposures likely derived from non-tailpipe road traffic emissions (brake and tyre wear), which have previously been associated with increases in inflammatory markers in the blood.