Explore the vast range of titles available.

Subauroral red (SAR) arcs are commonly observed ionospheric red line emissions. They are usually attributed to subauroral electron heating by inner magnetospheric heat flux (IMHF). However, the role of IMHF in changing the ionosphere‐thermosphere (IT) still remains elusive. We conduct controlled numerical experiments with the Thermosphere‐Ionosphere Electrodynamic General Circulation Model (TIEGCM). Coulomb collisional heat flux derived with the Comprehensive Inner Magnetosphere Ionosphere (CIMI) model and empirical subauroral polarization streams (SAPS) are implemented in TIEGCM. The heat flux causes electron temperature enhancement, electron density depletion, and consequently SAR arcs formed in the dusk‐to‐midnight subauroral ionosphere region. SAPS cause more substantial plasma and neutral heating and plasma density variations in a broader region. The maximum enhancement of subauroral red line emission rate is comparable to that caused by the heat flux. However, the visibility of SAR arcs also depends on the relative enhancement to the background brightness. Plain Language Summary The Earth's topside atmosphere is subject to energy inputs from the magnetosphere and solar wind. In addition to the Joule heating generated by high latitude plasma convection and energy flux carried by precipitating magnetospheric particles, magnetospheric energy can be also deposited in the ionosphere‐thermosphere via heat flux, that is, energy flows carried by low‐energy thermal electrons. When hot ions in the ring current collide with the cold plasma in the plasmasphere, heat conduction occurs and the resultant heat flux is transported along geomagnetic field lines to the footprint ionosphere. The additional heating raises the electron temperature in the subauroral ionosphere and modifies the ionosphere‐thermosphere states. This study uses first‐principles inner magnetosphere model and ionosphere‐thermosphere model to illustrate the thermodynamic coupling effects between the topside ionosphere and the magnetosphere, and compare the relative significance between the heat flux and plasma convection due to electrodynamic coupling. The numerical experiments show that the heat flux primarily increases electron temperature while subauroral plasma flow heats up both plasma and neutrals. Despite different physical mechanisms, the heat flux and subauroral plasma convection make comparable contributions to red line emission rates in the subauroral region. Key Points Inner magnetospheric heat flux increases subauroral ionospheric electron temperature and depletes the density to form subauroral red arcs Compared to subauroral polarization streams, the heat flux heating effects are only confined to electrons in the subauroral region The heat flux produces negligible impacts on ions and neutrals compared to subauroral polarization streams

In order to reduce greenhouse gas emissions and decrease dependency on depleting fossil fuel resources the shift to a renewable energy system is necessary. District heating and cooling systems are a viable solution to provide heat and cold in urban environments. Renewable heat and cold sources that may get incorporated in future urban energy systems will not provide the same high temperature output as current fossil fuel fired systems. Fifth generation district heating and cooling (5GDHC) systems are decentralized, bi-directional, close to ground temperature networks that use direct exchange of warm and cold return flows and thermal storage to balance thermal demand as much as possible. 5GDHC offers a way to incorporate low temperature renewable heat sources including shallow geothermal energy, as well as reduce total demand by recuperating generated heat from cooling and generated cold from heating. The large scale of 5GDHC allows for optimal design of technical parts like heat pumps and thermal storage vessels, while increasing overall system efficiency by incorporating a large variety of supply and demand profiles. We provide a definition for 5GDHC and show how this concept differs from conventional district heating systems. The Mijnwater system in Heerlen, the Netherlands is showing what a city-level 5GDHC system can look like.

The presented research covers the work carried out in the frame of the TCology project, conducted under funding of the Swiss Federal Office of Energy SFOE, evaluating the potential of thermochemical networks (TCNs) as an alternative to classical, hydronic district heating networks (DHN). The primary aim was to understand how TCNs can enhance the utilization of renewable energy in district heating systems through lossless energy distribution and long-term storage. The challenge was approached by numerical simulation of TCNs and 4th generation hydronic networks for performance comparison using Modelica as a modelling platform. Two case studies were defined for the performance comparison; i) space heating and domestic hot water application of 190 residential buildings / single family homes with a cumulated heat demand of 1.53 GWh per year and a peak power demand of 0.92 MW and ii) the application from i) extended with an industrial herb drying application with an annual heat demand of 0.1 GWh and a peak demand of 0.1 MW, featuring an open sorption process. The results identify biggest benefits for using TCN for low-temperature space heating applications with up to 5 times higher exergy efficiency and 2-3 times higher volumetric energy storage density compared to a classical DHN. Further, the possibility of providing the annual heat demand from a thermochemical storage with solar regeneration has been confirmed and quantified in terms of required storage volumes.

Any renovation of apartment buildings by replacing or keeping their heating devices usually means that high temperatures of the heat carrier are maintained, which restricts boosting the efficiency of a central heating supply system. This also limits the scope for a switch to more efficient systems such as low-temperature district heating systems. To assess the impact of reducing the heat carrier temperature on indoor heating with a constant radiator area, the article investigates several alternatives alongside a base case scenario. In one scenario, the modernization of a building is examined, either by retaining the current heating devices or by substituting them with devices of equal size. Another scenario explores the modernization of a building by exchanging the heating devices and adjusting the building’s heating system to accommodate ultra-low temperatures. The possibility to reduce the temperature of the heat carrier in the heating system without any renovation of the building has been addressed as well. This led to seven alternatives. The analysis of the hourly data of the heating system model for two typical months in a heating season has revealed that when the building retains its existing area of heating devices post-renovation, the temperature can be brought down to 60/40/20 °C. It was also discovered that lowering the heat transfer temperature to ultra-low parameters (45/25/20 °C) cannot be achieved by refurbishing the buildings without increasing the number of radiators, as the heating devices will fail to deliver adequate heat for space heating. Article in English. Daugiabučių namų šildymo sistemų integravimo į žemos temperatūros centralizuoto šilumos tiekimo tinklus vertinimas Santrauka Daugiabučių namų renovacija, keičiant ar paliekant jų šildymo prietaisus, paprastai reiškia, kad reikia išlaikyti aukštą šilumnešio temperatūrą, o tai riboja centralizuoto šilumos tiekimo (CŠT) sistemos efektyvumo didinimą. Be to, tai apriboja galimybę pereiti prie efektyvesnių sistemų, pavyzdžiui, žematemperatūrių CŠT sistemų. Siekiant įvertinti sumažintos šilumnešio temperatūros poveikį patalpoms šildyti, kai radiatorių plotas išlieka pastovus, straipsnyje išnagrinėtos kelios alternatyvos ir bazinis scenarijus. Pagal vieną scenarijų nagrinėjamas pastato modernizavimas, paliekant esamus šildymo prietaisus arba pakeičiant juos tokio pat dydžio prietaisais. Pagal kitą scenarijų nagrinėjamas pastato modernizavimas pakeičiant šildymo prietaisus ir pritaikant pastato šildymo sistemą itin žemai temperatūrai. Taip pat nagrinėta galimybė sumažinti šilumnešio temperatūrą šildymo sistemoje neatnaujinant pastato. Tai leido parengti septynias alternatyvas. Išanalizavus šildymo sistemos modelio valandinius dviejų tipinių šildymo sezono mėnesių duomenis paaiškėjo, kad, po renovacijos pastate išlaikant esamą šildymo prietaisų plotą, temperatūrą galima sumažinti iki 60/40/20 °C. Taip pat nustatyta, kad renovuojant pastatus neįmanoma sumažinti šilumos perdavimo temperatūros iki itin žemų parametrų (45/25/20 °C) nekeičiant esamo radiatorių skaičiaus, nes šildymo prietaisai nesugebės tiekti pakankamai šilumos patalpoms šildyti. Reikšminiai žodžiai: centralizuotas šilumos tiekimas (CŠT), pastatų modernizavimas, šildymo sistema, žema temperatūra.

\"The only series of step-by-step guides to succeeding in the skilled trades and achieving the American dream. At Your Best as an HVAC/R Tech is your playbook for learning if a career as an electrician is right for you, progressing from pre-apprentice to journeyman to master technician, and launching your own small business. Learn: What does a career as an HVAC/R tech look like? Why should you consider becoming an HVAC/R tech? How do you become a successful craftsman as an HVAC/R tech? How much can you make as an HVAC/R tech? What are your career options once you become an HVAC/R tech? How long does it take to be successful at each stage in a HVAC/R tech's career? How and where do you find work as an HVAC/R tech? What does it take to strike out on your own? What does it take to launch and build a successful small business? At Your Best is the only step-by-step handbook to finding if a career in the trades is right for you, educating yourself and earning the proper certifications, establishing yourself as an excellent apprentice and journeyman in the industry, and moving on to start your own small business in the trades. At each step of the way, your At Your Best playbook and its companion, www.AtYourBest.com, provide the information, recommendations, outside resources, and concrete actions needed for taking the next successful step in You, Inc. Whether you are beginning your first career, changing careers, or ready to move up and start your own business as a carpenter, plumber, HVAC/R tech, or other tradesman, this is the book that will tell you how. There currently over 6.5 million unfilled jobs in the skilled trades in the US. Despite being well-paying and secure, these jobs remain open because enough qualified candidates with the skills, attitude, and experience required do not exist. Moreover, plenty of opportunity exists for established tradespeople to start their own business, but they have no guidance. The At Your Best Playbooks series and www.AtYourBest.com change that.\" -- ONIX annotation.

The aim of this study was to investigate whether biomarkers of exposure (BoE) and potential harm (BoPH) are modified when smokers switch from smoking cigarettes to exclusive use of a tobacco heating product (THP) in an ambulatory setting. Participants in this randomised, controlled study were healthy volunteer smokers assigned either to continue smoking or switch to a THP, and a control group of smokers who abstained from cigarette smoking. Various BoE and BoPH related to oxidative stress, cardiovascular and respiratory diseases, and cancer were assessed at baseline and up to 180 days. In continuing smokers, BoE and BoPH remained stable between baseline and day 180, while THP users’ levels of most BoE reduced significantly, becoming similar to those in controls abstaining from cigarette smoking. Also at 180 days, significant changes in numerous BoPH, including total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, 8-epi-prostaglandin F2α type III, fractional concentration of exhaled nitric oxide and white blood cell count, were directionally consistent with lessened health impact. Our findings support the notion that the deleterious health impacts of cigarette smoking may be reduced in smokers who completely switch to using THPs.