bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing emissions in London schools with photovoltaics
Authors: Godoy-Shimizu Daniel , Evans Stephen , Korolija Ivan , Humphrey Dominic , Hong Sung-Min , Simons Gareth , Schwartz Yair , Ruyssevelt Paul , Steadman Philip , Mumovic Dejan , Mavrogianni Anna
Published: November 2021

This paper examines the potential for PV to improve the performance of primary schools in London. Disaggregate data including energy use is compared with modelled PV generation, showing that electricity demand could theoretically be met in 59% of the schools investigated. The impact of several key factors is then considered, including architectural heritage, building age and form. The results show that the greatest PV potential exists in newer schools, as well as those that are shorter and with less dense forms.
Applying Life Cycle Sustainability Assessment to maximise the innovation potential of new technologies for critical components in wind turbines
Authors: Lam Wai Chung , Regel Sofie De , Peeters Karolien , Spirinckx Carolin
Published: November 2021

Future wind turbines require flexible and economically affordable product development processes to obtain reliable and validated new concepts for larger wind turbines. Pitch bearings and gearboxes are considered critical components, due to their high contribution to the operational costs of wind farms and their high failure rates. Within the Horizon 2020 project INNTERESTING (Innovative Future-Proof Testing Methods for Reliable Critical Components in Wind Turbines) new concepts and technologies concerning two critical components are being developed for future wind turbines. Life Cycle Sustainability Assessment (LCSA) is applied iteratively to gain insights in the more demanding requirements for future wind turbines, specifically on the reduction of capital and operational expenditures and improvement of the environmental and socio-economic performance aspects of wind turbines in order to reduce the economic, environmental and social impact of the newly developed technologies. This paper focusses on the results of the first LCSA iteration for the business-as-usual reference scenarios which will serve as a benchmark and reference for the newly to be developed solutions in the project.
Solar energy potential at the Great St Bernard Pass
Authors: Notzon David , Florio Pietro , Schüler Andreas
Published: November 2021

The historical site of the Great St Bernard Pass, situated in the Alps at an elevation of 2469 m, records very high electricity consumptions. This study aims at evaluating the photovoltaic potential at the pass. The analysis was performed on the envelope surfaces of the building complex, taking into account the topography as well as typical climate data issued from a weather station located on site. It is found that during the months from June to October, each year, 54 MWh of electricity could potentially be generated, which is more than what could be produced by the same system in the climate of Geneva.
Dynamic LCA of a single-family house, equipped with a micro-cogeneration unit, using a variable share of biomethane
Authors: Padey Pierryves , Fesefeldt Marten , Goulouti Kyriaki , Lasvaux Sébastien , Capezzali Massimiliano
Published: November 2021

The current study presents the CO2-eq emissions of the operational energy use of a single-family house, equipped with a micro-cogeneration unit. A back-up boiler and electricity from the grid cover the remaining energy demand, not covered by the micro-CHP. Two different technologies are evaluated, i.e. ICE and fuel cell systems, operating with a variable share of biomethane, while two different substrates were considered for the biomethane generation. A dynamic LCA was applied for the electricity mix, coming from the grid, using different time steps. The results show that producing biomethane from biowaste compared to conventional natural gas is beneficial, in terms of CO2-eq emissions, independently of the micro-CHP technology, while the total CO2-eq emissions of the fuel cell technology are higher than those of the ICE, independently of the substrate and the biomethane share.
Impact of shared battery energy storage system on total system costs and power peak reduction in commercial buildings
Authors: Skoglund Ida E. U. , Rostad Mette , Thorvaldsen Kasper E.
Published: November 2021

The power system is experiencing an increasing share of renewable and intermittent energy production and increasing electrification. However, these changes are creating high power peaks, are straining the grid and call for expensive investments in expansions and improvements. This paper examines how the operational strategy of shared battery energy storage systems (s-BESS) can address these issues for commercial buildings with relatively high power peaks. Due to the uncertainty in long-term costs when subject to a measured peak (MP) grid tariff, the scheduling of the battery is optimised with a receding horizon control algorithm. The optimisation model is used on a Norwegian real-life case study to find the best possible configuration with an already existing battery. Although current Norwegian regulations challenge the possibility for shared metering and billing for a s-BESS configuration, the results show that the total system cost was reduced by 19.2% compared to no battery. The community peak was reduced by 17.8% compared to no battery and 6.22-17.5% compared to individual storage, which indicates that s-BESS is of value for the DSO as well.
Implementation of machine learning techniques for the quasi real-time blind and electric lighting optimization in a controlled experimental facility
Authors: Basurto Chantal , Boghetti Roberto , Colombo Moreno , Papinutto Michael , Nembrini Julien , Kämpf Jérôme H
Published: November 2021

Machine Learning techniques have been recently investigated as an alternative to the use of physical simulations, aiming to improve the response time of daylight and electric lighting performance-predictions. In this study, daylight and electric lighting predictor models are derived from daylighting RADIANCE simulations, aiming to provide visual comfort to office room occupants, with a reduced use of electric lighting. The aim is to integrate an intelligent control scheme, that, implemented on a small embedded 32-bit computer (Raspberry Pi), interfaces a KNX system for a quasi-real-time optimization of the building parameters. The present research constitutes a step towards the broader goal of achieving a unified approach, in which the daylight and electric lighting predictor models would be integrated in a Model Predictive Control. A verification of the ML performance is carried-out by comparing the model predictions to data obtained in monitoring sessions in autumn, winter and spring 2020-2021, resulting in an average MAPE of 19.3%.
Non-Intrusive Luminance Mapping via High Dynamic Range Imaging and 3-D Reconstruction
Authors: Kim Michael , Tzempelikos Athanasios
Published: November 2021

Continuous luminance monitoring is challenging because high-dynamic-range cameras are expensive, they need programming, and are intrusive when placed near the occupants’ field-of-view. A new semi-automated and non-intrusive framework is presented for monitoring occupant-perceived luminance using a low-cost camera sensor and Structure-from- Motion (SfM)-Multiview Stereo (MVS) photogrammetry pipeline. Using a short video and a few photos from the occupant position, the 3D space geometry is automatically reconstructed. Retrieved 3D context enables the back-projection of the camera-captured luminance distribution into 3D spaces that are in turn re-projected to occupant-FOVs. The framework was tested and validated in a testbed office. The re-projected luminance field showed with good agreement with luminance measured at the occupant position. The new method can be used for non-intrusive luminance monitoring integrated with daylighting control applications.
Data-driven occupant-centric rules of automated shade adjustments: Luxembourg case study
Authors: Derbas Ghadeer , Voss Karsten
Published: November 2021

This study presents key findings of observed datasets in a nearly zero-energy office building for over 66 working days from June to mid-September in 2019, Luxembourg. Measurements of indoor and outdoor environmental parameters as well as user-shade override adjustments were extracted from the KNX-based building management system (BMS) in 47 office rooms located in three typical floor levels. Relative frequency and “rate of change” of blind use were analysed in terms of window orientation, occupancy level, and the time of the day. Logistic regression and data mining techniques were used to identify potentially useful and understandable occupant behaviour patterns and reveal the main triggers behind blind adjustments. The well-designed automation system together with the inner glare protection formed the base of very low user-shade interactions. A mean of 0.184 manual blind adjustments per day per office. Eight regression sub-models were developed and all were incapable of predicting user-shade lowering and raising events. Alternatively, two user profiles were mined based on 20 rules gained from clustering analysis: user (ß) was representing the passive user, and user (μ) the medium user. Overall, we conclude that the automated shading system in this building is satisfactory, user-friendly, and a robust control system.
A review of common human errors in design, installation, and operation of multiple-zone VAV AHU systems
Authors: Torabi Narges , Burak Gunay H. , O’Brien William
Published: November 2021

Faults in air-based heating, ventilation, and air conditioning (HVAC) systems lead to energy waste and discomfort. While the emphasis of fault detection and diagnostic (FDD) research has been on hard faults in actuators, sensors, and equipment, faults arising from human errors account for a significant portion of faults occurring in HVAC systems. In this paper, human errors occurring in air handling units (AHUs) and variable air volume (VAV) thermal zones during design, construction, and operation phases are identified through a review of the literature. Then, the faults are divided into six main categories. Based on case studies investigating these faults, the impact of each fault category on occupant comfort, energy consumption, and equipment life is discussed. The authors provide recommendations to minimize human errors in AHUs and VAV zones throughout the building life cycle.
Environmental preferences of occupants: A multi-domain approach in the Swiss open office case study
Authors: Barthelmes Verena M. , Karmann Caroline , Viviana González S. , Chatterjee Arnab , Wienold Jan , Andersen Marilyne , Licina Dusan , Khovalyg Dolaana
Published: November 2021

Defining indoor environmental conditions that meet the needs and preferences of occupants in open space offices can be challenging since the same space might be occupied by people with different individual needs and preferences regarding what constitutes a comfortable work environment. This study presents outcomes of a set of longitudinal point-in-time comfort surveys that were designed to capture instantaneous preference votes about momentary environmental conditions twice a day covering all four major domains of IEQ. The surveys were disseminated during two weeks across three seasons (fall, winter, summer) to 31 occupants in a Swiss open space office and supplemented with environmental data simultaneously measured in-situ at the occupant’s desk level. These surveys (up to 670 responses per environmental domain) offered insights into the discrepancies of expressed environmental preferences with respect to measured environmental conditions in open space offices.
Influence of some specific meteorological events on indoor radon dynamic in western Switzerland
Authors: Rey J , Goyette S , Palacios M , Barazza F , Gandolla M , Goyette Pernot J
Published: November 2021

Radon is a natural radioactive gas that may cumulate in indoor environments. The impacts of weather events on indoor radon concentration had been explored in different places around the world but only marginally in Switzerland. Using basic statistical analysis, this study investigates different meteorological parameters’ influence on indoor radon concentrations and shows that outdoor air temperature is the most influential beyond others. Finally, this paper highlights the importance of radon dynamic in buildings, a topic often overlooked by construction professionals and the broader public in Switzerland.
A survey-based approach used to analyse the indoor satisfaction and productivity level of user in smart working during lock-down due to the COVID-19 pandemic
Authors: Salamone Francesco , Belussi Lorenzo , Danza Ludovico , Meroni Italo
Published: November 2021

Italy was the first country in Europe to enter lock-down due to COVID-19 pandemic. Most employees have been forced to adopt a work at home solution to avoid any possibility of spreading the virus. The article presents the results of a survey carried out in March-June 2020, during the first lockdown in Italy, aimed at investigating how people perceive the Indoor Environmental Quality (IEQ) of their households during working from home. The questionnaire consists in a general section reporting information about participant, households and rooms where they perform the working activities; a specific section reporting feedbacks on each IEQ aspects (thermal, visual comfort, air and acoustic quality), overall comfort, productivity and other external variables that can affect users’ well-being during working hours. A total of 330 participants from all over the Italian territory signed the consent to participate in the survey over a period of about 3 months. The dataset was used to define the global level of satisfaction, perception, preference and interference with work at home, considering the main indoor environmental factors. The Machine Learning (ML) approach was applied to identify the most useful model to predict the overall comfort satisfaction.
Electricity demand flexibility potential of optimal building retrofit solutions
Authors: Thrampoulidis Emmanouil , Orehounig Kristina , Hug Gabriela
Published: November 2021

Swiss buildings, the majority of which will last beyond 2050, are responsible for a large share of energy demand and greenhouse gas emissions. Hence, building retrofit is considered as one of the most promising approaches to reduce those shares. However, reducing the energy load should not be an end in itself. The continuous integration of intermittent power sources in the electricity grid imposes new challenges to the supply-demand problem that might directly affect the retrofit process and vice-versa. Therefore, this paper aims to develop a model to analyze the demand flexibility potential of optimal retrofit solutions. Co-simulation and a rolling horizon approach are used to derive upper and lower electricity consumption profiles given some temperature comfort bands. Within those electricity bands, the feasible area provides insights on the extent by which the electricity consumption can be shifted within the comfort constraints. The method is applied to a building archetype. Results show that when the comfort constraints are relaxed the feasible area increases, e.g., up to five times for the case of enhancing the roof insulation, while building retrofit influences the electricity bands. Such a method could enhance the retrofit process and address both the emissions’ and the supply-demand balancing problem.
Effect of thermal mass of insulated and non-insulated walls on building thermal performance and potential energy saving
Authors: Haj Hussein M , Monna S , Juaidi A , Barlet A , Baba M , Bruneau D
Published: November 2021

The presented study aims to evaluate the effect of thermal mass in heavyweight construction in residential buildings in Palestine on indoor thermal environment using a building performance simulation tool. The most used residential building types, shapes and sizes were used as typical models for indoor environment performance simulation. The paper used a sensitivity analysis for four different scenarios according to the location of thermal insulation in the wall for two climatic zones, when no heating and cooling was used. The building material’s thermal properties, infiltration, activities, time schedule, electric lighting and glazing selection were based on onsite studies. The results show that the internal thermal mass of the studied buildings influences their thermal performance and future potential energy demand for heating and cooling. Buildings with insulation positioned on the outside, with high thermal mass and high thermal time constant showed the best thermal performance for different climatic zones, whereas buildings without thermal insulation or with insulation from the inside showed the worst thermal performance. The position of thermal insulation will affect potential energy demand for heating and cooling in the residential buildings.
Cost optimal energy retrofit strategies for public administrative buildings: A Cairo case study
Authors: Hamada A , Raslan R , Mumovic D
Published: November 2021

The Egyptian government is currently constructing a new governmental quarter in the New Administrative Capital City, located east of Cairo. A planned relocation for all ministerial authorities to the New Capital City will leave a vacant governmental estate in Cairo. The study of the energy retrofit options provides a unique opportunity to reduce energy use and maximize the benefit from the anticipated investment in the re-use to be implemented within this stock. However, energy retrofit was found to be under-researched in the Egyptian context. This paper presents a pilot study that aims to identify cost optimal retrofit strategies for one of the soon to be vacated buildings, the Central Agency for Public Mobilization and Statistics (CAPMAS). Using DesignBuilder, an energy modelling study was implemented to estimate the existing performance of the building, assess the projected performance after a change of use (to an office building), and evaluate the cost optimality and the savings associated with the application of retrofit measures. The study found that the feasibility of implementing retrofit can be significantly offset by the discount rates in Egypt. As such, maintaining economic stability and considering non-economic incentives can be key drivers to increasing the energy retrofit uptake in Egypt.
Should biogenic carbon be analysed separately in the calculation of the GWP indicator?
Authors: Hoxha Endrit , Passer Alexander
Published: November 2021

The life cycle assessment method is widely accepted for calculating the environmental impacts of buildings. However, the approaches used to translate greenhouse gas emissions to a global warming potential score are largely criticised. By following a static approach (known as 0/0) and a time-dependent approach (known as dynamic) in this paper, we assessed the environmental impacts of two buildings with structures made of reinforced concrete and wood, respectively. The relative difference between the results calculated with the 0/0 approach and the time-dependent approach were larger for the building with the wooden structure. A more detailed analysis identified biogenic carbon as the source that was most responsible for this difference in results. For this reason, biogenic carbon should be treated separately and must be calculated with the time-dependent approach. Meanwhile, the impacts from fossil energy sources should be calculated with the 0/0 approach.
Adapting residential envelope assemblies for full circularity
Authors: Mayer Matan
Published: November 2021

Residential external wall assemblies are among the key contributors to embodied carbon emissions in the building industry. Their design, however, is still largely oriented towards linear consumption trajectories of extraction-use-waste. Within this context, this paper investigates how established material recovery potential assessment metrics could be used to inform design decisions aimed at improving circularity in buildings. A redesign of a typical timber frame assembly is presented and its material recovery performance is compared to standard systems. Results show a 35%-47% improvement in material recovery potential.
Deriving global carbon budgets for the Swiss built environment
Authors: Priore Y D , Jusselme T , Habert G
Published: November 2021

In order to limit global warming, remaining carbon budgets have been defined by the IPCC in 2018. In this context translating global goals to local realities implicates a set of different challenges. Standardized methodologies of allocation can support a target-cascading process. On the other hand, local strategies and norms are not currently designed to directly respond to limited carbon budgets in a 2050 horizon. The life cycle assessment of buildings implicates an intricate cross-industry and cross-border carbon accounting. For these reasons, effective and aligned carbon targets are needed to support and guide all actors in the construction sector. This research aims at addressing these challenges by developing a new methodology of allocation of a global carbon budget at different scales using the Swiss built environment as a case study. This approach allows the assessment of current best practices in regards to limited carbon budgets. Results show misalignment of global goals with current practices at all levels and present the magnitude of effort that would be required to have a chance to limit global warming to 1.5°C.
Design for Disassembly (DfD) in construction industry: a literature mapping and analysis of the existing designs
Authors: Ostapska Katarzyna , Gradeci Klodian , Ruther Petra
Published: November 2021

A systematic search of scientific literature on the topic of Design for Disassembly (DfD) in the architecture, engineering, and construction (AEC) industry was performed with a special focus on study cases. The results were augmented by electronic magazine search due to the non-representative amount of data found in the scientific database. Results show the domination of wood and steel solutions among architects and engineers designing for disassembly. Frame structural system is preferable. DfD structures are mainly located in Europe but observed in the whole world and growing exponentially since 90'. The database with 117 built DfD study cases is made available online and will be further developed.
Optimization of photoluminescent materials for lighting energy saving in the built environment
Authors: Chiatti C , Fabiani C , Pisello A L
Published: November 2021

In the last decades, fossil fuels have become the primary resource for electricity generation, contributing to the aggravation of problems like global warming and ozone depletion. For this reason, innovative solutions are being continuously developed in order to improve energy efficiency in the construction sector. Beyond heating and cooling, urban lighting plays a significant role on the final energy consumption of a city, including both indoors and outdoors. In this work, photoluminescent materials are investigated as possible light sources to be implemented in urban lighting systems, focusing on the free-cost and renewable luminous gain they provide after being exposed to a proper radiation. In particular, commercially available photoluminescent powders are evaluated by means of spectroradiometric techniques and using a specifically designed experimental setup. Measurements are repeated for different intensities and wavebands of irradiation to identify the most promising “pigment-lamp” combination in terms of (i) luminous intensity and (ii) photoluminescence duration. Results show that the shorter the distance between the emission spectra of the exciting source and the photoluminescent powder, the better the performance of the latter. Therefore, the choice of both afterglow and exciting source cannot be independent from the final system’s application and the required end-use lighting level.
Subjective assessment of visual comfort in a daylit workplace with an electrochromic glazed façade
Authors: Jain S , Karmann C , Wienold J
Published: November 2021

Electrochromic (EC) glazing is increasingly employed in building façades to achieve better visual comfort for the occupants. EC glazing can modulate the light entering through the façade by varying the solar transmittance of the glass and therefore can work as a shading strategy to minimize solar heat gains or glare. However, it also alters the spectrum and distribution of light entering through the façade, which influences certain visual attributes associated with a space. This user assessment study evaluates some of these attributes including the colour perception of the elements inside and outside the room, the uniformity of daylight distribution, the clarity of the view through the glazing and the perception of glare when the sun is in the field of view. Results indicate a visual transmittance (τv) of 0.6% is sufficient to control glare when the sun is in the peripheral field of view (FOV) while τv,n-n of 0.14% is required to control glare when the sun is close to the central FOV. Most of the participants did not perceive the colours of outdoor environment as natural when seen through EC glazed window. The majority of participants also desired to change the glazing configuration by adding an additional shading device.
Reconstruction of some cosmological models from the deceleration parameter
Authors: Beesham Aroonkumar
Published: November 2021

Since the discovery of the late-time acceleration of the universe, researchers are still trying to fnd an explanation for it. This is regarded as the most important unsolved problem in cosmology today. The most favoured explanation is dark energy, an unknown or exotic form of matter with negative pressure. One may argue that particle physics may provide the answer in time. Currently, the LambdaCDM model is regarded as the best model. Although this model is reasonably successful and widely accepted, there is growing interest in looking at alternatives. Some of the reasons for this are the fne-tuning, coincidence, infationary paradigm and cosmological constant problems, and whether general relativity is valid on large scales. One focus in trying to understand dark energy is to assume some form of the scale, Hubble or deceleration parameter (or some other reasonable assumption), and then to see how well the model fts in with current observations. This approach is broadly called reconstruction. In this talk, we focus on the deceleration parameter. We provide a brief review of the various forms of the deceleration parameter that have been employed in the past in cosmology, and then focus on some particular forms of interest which have drawn some attention. We note that it is most worthwhile to study alternative dark energy and dark gravity models in order to fully understand the entire space of possibilities.
Estimating the Chirp Mass of Eccentric Inspiraling Binary Systems from Time-Frequency Representations of their Gravitational Radiation
Authors: Pinto Innocenzo M
Published: November 2021

Using the simplest yet meaningful Peters-Mathews model describing the orbital damping of a compact binary system under the emission of gravitatonal radiation, we show that the chirp-mass of an eccentric inspiraling binary, and its (Keplerian) orbital eccentricity at some reference time, can be estimated from the time-frequency skeleton of its gravitational wave signal. The estimation algorithm is nicely simple, and is robust against the non-ideal (non Gaussian, non stationary) features of detector noise.
Optimization of the Euro-Asian network of gravitational detectors for detecting the radiation of collapsing objects
Authors: Rudenko V , Andrusenko S , Krichevskiy D , Manucharyan G
Published: November 2021

A Euro-Asian network of four gravitational-wave (GW) interferometers is considered, taking into account the plan to create such a detector in Novosibirsk. The efficiency of the network is assessed by typical numerical criteria, which also depend on the characteristics of the received signal. In this work, we calculate the optimal orientation of the Novosibirsk detector for the problem of detecting GW radiation accompanying the collapse of the progenitor star with an initial angular momentum. The specificity of the scenario is the presence of the so-called. bar stage deformation, for which the shape of the emitted GW signal is known.
Pulsar: physical generalization of the galactic time-space
Authors: Avramenko A E
Published: November 2021

The article considers a complex of geometric representations of space-time, based on general dynamic theories of celestial mechanics in close connection with pulsar astrometry as the physical basis of coordinate-time transformations within the solar system and galactic space as a whole. The pulsar time scale is considered as a certain material system with continuous and stable motion, representing a certain measurable parameter – the rotation period P, which changes as a function of the independent time variable – its derivative. The physical pulsar scale is a sequence of measured daily increments of the initial radiation period within any duration. According to observations at the BSA radio telescope (Pushchino) of the pulsar B0950+08, the time scale was determined with an initial period of P0=0.2530653211840410 s on the date MJD0 = 58971 (02.05.2020; 21h.58m.07s). A measured daily increment ΔP = 1.4441·10E-11 s corresponds to the measured value of the derivative P = 1.6759949886E-16, which is determined by the observational timing data. Measured ΔP are defined in the 25th decimal place. Up to 14-15 digits, Δ P there is a pulsar time scale with femtosecond resolution. From 15-16 to 25 digits Δ P is presumably sequential fixation of discrete states of microparticles during quantum-mechanical interactions of matter and electromagnetic radiation of a pulsar. According to our hypothesis, the diversity of the material world and physical processes occurring in celestial and quantum mechanics are finite and it can be generalized. This implies the inseparable unity of physical laws in four-dimensional space of celestial and quantum mechanics, detectable on pulsar time scales under the same conditions.
On the Schwarzschild solution in TEGR
Authors: Emtsova E D , Krššák M , Petrov A N , Toporensky A V
Published: November 2021

Conserved currents, superpotentials and charges for the Schwarzschild black hole in the Teleparallel Equivalent of General Relativity (TEGR) are constructed. We work in the covariant formalism and use the Noether machinery to construct conserved quantities that are covariant/invariant with respect to both coordinate and local Lorentz transformations. The constructed quantities depend on the vector field ξ and we consider two different possibilities, when ξ is chosen as either a timelike Killing vector or a four-velocity of an observer. We analyze and discuss the physical meaning of each choice in different frames: static and freely falling Lemaitre frame. Moreover, a new generalized free-falling frame with an arbitrary initial velocity at infinity is introduced. We derive the inertial spin connection for various tetrads in different frames and find that the “switching-off” gravity method leads to ambiguities.
Including precision clocks into space-based net as gravitational antennas
Authors: Izmaïlov G N , Ozolin V V
Published: November 2021

Here we propose to use a precision clock in a space-based ultra-precise clock network to register sources of low-frequency gravitational waves of cosmic origin in the range of 10-3 ÷ 0.1 Hz. We also show that the method of comparing clocks at inland and intercontinental distances (very long baseline interferometry), originally developed for radio astronomy and geodesy, can be used as a prototype method for recording gravitational waves. Estimates of the measurement accuracy are given. An analyse of precise clocks possibilities for experimental estimates for rotation parameter of Gödel universe and GW recordings is offered, which in particular opens up the prospect of registering circularly polarized gravitational waves. Some new problems of small time intervals registration from general relativity, thermodynamics and quantum mechanics points of view are discussed.
Constrains on an uniform model for Dark Matter and Dark Energy
Authors: Izmaïlov G N
Published: November 2021

In this paper, outlined some of the most important concepts about Dark Matter and methods of their registration, in particular by using SQUIDs, a toy uniform model for Dark Matter and Dark Energy is analyzed. In the frame of the model Dark Matter particles is interpreted as excitations of Dark Energy field. Some constrains are considered. The devices based on SQUID, in particular the SQUID-paramagnetic absorber and the SQUID-magnetostrictor systems, both suitable for investigations of above problems, are considered. Estimates, are carried out within this model, indicate the possibility of experimental detection of the “ether wind” pressure, created by the non-corpuscular incoming flow, corresponding to the galactic orbital motion of the Earth.
Gravitational Radius in view of Existence and Uniqueness Theorem
Authors: Meierovich Boris E
Published: November 2021

Talking about a black hole, one has in mind the process of unlimited self-compression of gravitating matter with a mass greater than critical. With a mass greater than the critical one, the elasticity of neutron matter cannot withstand gravitational compression. However, compression cannot be unlimited, because with increasing pressure, neutrons turn into some other “more elementary” particles. These can be bosons of the Standard Model of elementary particles. The wave function of the condensate of neutral bosons at zero temperature is a scalar field. If instead of the constraint det gik < 0 we use a weaker condition of regularity (all invariants of the metric tensor gik
are finite), then there is a regular static spherically symmetric solution to Klein-Gordon and Einstein equations, claiming to describe the state to which the gravitational collapse leads. With no restriction on total mass. In this solution, the metric component grr
changes its sign twice: g
rr (r) = 0 at r=rg
and r=rh > rg
. Between these two gravitational radii the signature of the metric tensor gik
is (+, +, -, -). Gravitational radius rg
inside the gravitating body ensures regularity in the center. Within the framework of the phenomenological model “λψ4
”, relying on the existence and uniqueness theorem, the main properties of a collapsed black hole are determined. At r = rg
a regular solution to Klein-Gordon and Einstein equations exists, but it is not a unique one. Gravitational radius rg
is the branch point at which, among all possible continuous solutions, we have to choose a proper one, corresponding to the problem under consideration. We are interested in solutions that correspond to a finite mass of a black hole. It turns out that the density value of bosons is constant at r < rg. It depends only on the elasticity of a condensate, and does not depend on the total mass. The energy-momentum tensor at r ⩽ rg corresponds to the ultra relativistic equation of state p = ɛ/3. In addition to the discrete spectrum of static solutions with a mass less than the critical one (where grr
< 0 does not change sign), there is a continuous spectrum of equilibrium states with grr(r) changing sign twice, and with no restriction on mass. Among the states of continuous spectrum, the maximum possible density of bosons depends on the mass of the condensate and on the rest mass of bosons. The rest energy of massive Standard Model bosons is about 100 GeV. In this case, for the black hole in the center of our Milky Way galaxy, the maximum possible density of particles should not exceed 3 × 1081 cm-3.
R+RG gravity with maximal Noether symmetry
Authors: Pokrovsky Yu E
Published: November 2021

A Noether symmetric, 3rd order polynomial in the Riemann curvature tensor
R
αβμν
extension of the General Relativity (GR) without cosmological constant (R+RG gravity) is suggested and discussed as a possible fundamental theory of gravity in 4-dimensional space-time with the geometric part of the Lagrangian to be

L

R
+
R
G

=

−
g

2
k

R

(

1
+

G

G
P

)

. Here

k
=

8
π

G
N

c
4

is the Einstein constant,

g
=
det

(

g

μ
ν

)

,

g

μ
ν

- the metric tensor, GN
- the Newton constant, c - the speed of light,

R
=

R

μ
ν

μ
ν

- the Ricci scalar,

G
=

R
2

−
4

R

μ
ν

R

μ
ν

+

R

α
β
μ
ν

R

α
β
μ
ν

- the Gauss-Bonnet topological invariant, and GP
- a new constant of the gravitational self-interaction to model the cosmological bounce, inflation, accelerated expansion of the Universe, etc. The best fit to the Baryon Acoustic Oscillations data for the Hubble parameter H (z) at the redshifts z<2.36 leads to

G
P

1
/
4

=

(

0.557
±
0.014

)

T
p

c

−
1

with the mean square weighted deviation from the data about 3 times smaller than for the standard cosmological (ΛCDM) model. Due to the self-gravitating term ∼RG the respective Einstein equation in the R+RG gravity contains the additional (tachyonic in the past and now) scalar (spin = 0) graviton and the perfect geometric fluid tensor with pressure-and matter-like terms equal to the respective terms in the ΛCDM model at |z| 1. Some predictions of this R+RG gravity for the Universe are also done.
Multiworld motives by closed time-like curves
Authors: Shepelin A V , Rostom A M , Tomilin V A , Il’ichov L V
Published: November 2021

We propose a new model, entitled S-CTC, for description of quantum systems in the presence of CTC – closed time-like curves. The model is based on the viewpoint on any quantum state as an observer’s state of knowledge of the system preparation procedure. We compare and contrast our S-CTC model with D-CTC and P-CTC models and show that S-CTC shares special quantum features with both D-CTC and P-CTC. As far as the interaction of the quantum system with itself coming from the future concerns, S-CTC is formally equivalent to P-CTC. On the other hand, when calculating outcome probabilities for a measurement within the time interval between the entrance and exit of CTC, S-CTC becomes equivalent to D-CTC. Both these models require the concept of alternative realities (worlds) where different measurement outcomes are recorded and alternative connections of these realities by CTC.
The principle of materiality of space and the theory of fundamental fields
Authors: Zhuravlev V M
Published: November 2021

The work formulates the principle of materiality of space and on its basis a brief critical analysis of the general ideology of the Special and General Theories of Relativity is carried out. The connection of the new principle with the previously developed Topological Theory of Fundamental Fields (TTFF) is considered. A method of constructive implementation of the principle of materiality in the framework of the physical theory of fundamental fields is considered. General equations of the dynamics of markers of material points of physical space are derived and their physical meaning is established.
Didactic Engineering as a research method in physics teaching
Authors: Prada-Núñez R , Gamboa-Suárez A A , Avendaño-Castro W R
Published: November 2021

Several mathematical concepts have application in physics; this paper reports the results of a pedagogical investigation based on the methodology known as didactic engineering, which has been proposed with the aim of improving the skills exhibited by a group of eleventh grade students from a private institution in the interpretation of kinematic graphs. The concept of the slope of the straight line and how this mathematical concept can represent velocity or acceleration according to the variables considered in the kinematics graph provided was enhanced in the pedagogical intervention. This methodology offers a process of internal validation, after comparing the results obtained in a knowledge test at two different points in time (pre-test and post-test). The results allowed us to identify improvements in all students in terms of basic kinematics graph interpretation skills, and a group of students stood out by advancing in more complex reasoning and interpretation processes. These results contribute to the improvement of the pedagogical practices of Physics teachers at secondary and middle school levels, making them more competent when they enter higher education.
Physics in architecture projects, a perfect match on Alamillo’s bridge by Santiago Calatrava
Authors: Acuña-Prada M C , Coronel-Ruiz L K , Prada-Nuñez R
Published: November 2021

The Alamillo’s bridge by Santiago Calatrava was studied, who develops projects and structures with morphological, sculptural, and conceptual aspects associated with physics and contemporary architecture, through experimentation with forms of nature, the movement of the human body and, materials such as steel and reinforced concrete. The methodological framework corresponded to a documentary study that determined the importance of the bridge from its historical context as part of the infrastructure of the 1992 Universal Exposition in Seville, as well as the analysis of the physical concepts used in its design and construction; and, a quantitative-descriptive study applied to the seventh semester students of the Architecture program of the Universidad Francisco de Paula Santander, Colombia, which determined their level of recognition of the physical concepts of this project. As a finding, it is highlighted that this bridge applied physical concepts such as: aerodynamics, torsion, compression, tension, traction, and gravitation, in compliance with its formal-aesthetic design criteria, and those students recognize the physical concepts, design and technical characteristics-formal, typical of the project. Likewise, it was determined that this urban landmark represents a comprehensive solution that solves the structure and form through solutions associated with the field of engineering, architecture, and physics.
Underlying variables in the understanding of movement in engineering students
Authors: Suárez O J , Gamboa-Suárez A A , Hernández-Suárez C A
Published: November 2021

This article describes the understanding of motion by active students taking Newtonian physics for engineering, supported by active learning, during the pandemic due to COVID-19; in addition, an unsupervised predictive model of learning achievement was constructed from variables identified using the principal component analysis technique on the responses. the instrument used is the modified test of understanding graphs-kinematics comprehension. students from two universities in Bogotá, Colombia participated. The results show a lower level of accuracy in students in remote face-to-face mode, compared to the reference group of physical presence; by way of reflection, the forced educational experiment implies resizing the teaching activity in the teaching and learning of movement.
Comparison of analytical methods and numerical methods in modeling the physical phenomenon of heat conduction with free radiation
Authors: Nolasco Serna C , Afanador Garcia N , Guerrero Gómez G
Published: November 2021

The development of mathematical setting for modeling heat conduction phenomena in the presence of radioactive effects is well known. The importance in the study of heat conduction in relation to radioactive effects is relevant in several engineering applications such as combustion, materials science, fluid mechanics and other areas. This research is based on the mathematical model of the heat equation to study the physical phenomenon of heat transfer along a metal bar with slightly insulated sides with the effect of free radiation. To calculate the temperature function that allows modeling the heat transfer process along the bar, the Fourier series solution is constructed step by step, in addition an alternative method of calculating the temperature by using the explicit numerical method is given. The calculation of the temperature along the bar is compared by analytical and numerical method by computing the percentage error and different temperature profiles are plotted to verify the fit of the two approaches. The methods developed throughout the research can be extended to other types of physical phenomena that are useful in related research and in education in engineering subjects such as fluid mechanics and heat transfer.
Modeling of heat transport phenomena using the equations of mathematical physics
Authors: Nolasco Serna C , Afanador Garcia N , Guerrero Gómez G
Published: November 2021

The study of physical phenomena that include conservative principles is part of the research field of the equations of mathematical physics. To deepen in methods to solve the equations of mathematical physics is a contribution in understanding the modeling of applications in different areas. This research studies the physical phenomenon of heat transport with convection from the viewpoint of modeling with differential equations. The advantage of working with equations is to apply the techniques of mathematical analysis and numerical methods to obtain the temperature function. In the research, the solution of the heat transport model is computed according to the analytical method of separable variables in order to represent the temperature function as a trigonometric series. With the help of a simple numerical method, it is possible to derive a scheme of calculation of the temperature function. By performing a case study, the methods are compared, and their fit is verified by simulation.
Analysis of linear and non-linear effects in the frequency domain for a three-channel optical transmission system
Authors: Galvis-Velandia J E , Puerto-López K , Ramírez-Mateus J
Published: November 2021

This paper presents the analysis of a wavelength division multiplexer communication system in the frequency domain, with the objective of visualizing the incidence of the linear phenomena of attenuation and chromatic dispersion, together with the phenomenon of phase self-modulation, the Kerr electro-optical effect and fourth wave mixing. The analyzed system consists of a laser transmitter with a Mach-Zender modulator and a standard G.625b single-mode fiber link transmitting three optical signals of 10 mW, 25 mW and 50 mW at a fundamental wavelength of 1550 nm at a rate of 10 Gbps. This system is analyzed through a graphical user interface programmed by the authors in the Python environment, which calculates the parameters corresponding to each phenomenon and graphically represents the transmission results at distances of 50 km and 100 km. The analysis methodology consists of varying the spectral separation of the transmitted channels, initially considering a spectral separation of 2 nm and subsequently a spectral separation of 0.2 nm, observing as a result that the harmonics generated by the fourth wave mixing phenomenon considerably alter the spectral density of the transmitted signals, since the energy of the harmonics is equal to the power of the transmitted signals. On the other hand, with the spectral spacing of 0.2 nm, it is obtained that, although the harmonics alter the spectral density waveform, the bandwidth is not compromised by these additional signals.