Insulation Measures Research Articles

Moisture absorption characteristics and thermal insulation performance of thermal insulation materials for cold region tunnels

Laying thermal insulation is one of the common thermal insulation measures to prevent frost damage of tunnels in cold regions and the performance of thermal insulation material directly determines the effectiveness of freeze-proofing and insulation of thermal insulation layer. As an important parameter for evaluating the performance of thermal insulation materials, thermal conductivity is generally affected by density, humidity, temperature and other factors, therefore this paper will mainly focus on when the air humidity in the tunnel is too high, the moisture absorption of insulation materials may occur in the humid environment for a long time, which will lead to the increase of moisture content of insulation materials. Hence tunnels in cold regions, generally exhibit lower temperature conditions, thus the water inside the insulation material is easy to freeze, which will greatly improve the thermal conductivity of the material and reduce its thermal insulation effect. Therefore, it is of great significance to study the thermal insulation performance of cold-regions tunnel thermal insulation materials after moisture absorption and complete freezing.

Effect of comprehensive thermal insulation measures on body tempreture and stress index in patients with low body mass index of thoracic surgery

Objective To investigate the changes of body temperature and the effect of nursing intervention in patients with low body mass index (BMI<18.5 kg/m2) during thoracic surgery. Methods Sixty patients with low BMI who underwent thoracic surgery in the Operating Department of the 4th Hospital of Hebei Medical University from June 2016 to December 2018 were randomly divided into observation group and control group, with 30 cases in each group. In addition, 30 patients with normal BMI (18.5-23.0 kg/m2) who underwent thoracic surgery in the same period were selected as the normal group. The observation group adopted comprehensive thermal insulation measures during the operation, and the control group and the normal group adopted routine insulation measures. The patient's body temperature of three groups was compared at each time point: entering operation room, disinfection, body cavity exploration , cutting specimens, closing the chest, suture skin and exiting operation time. the occurrence of adverse reactions during surgery, the blood coagulation index and lactic acid in the peripheral blood before and at the end of surgery, and the peripheral blood inflammatory factor levels were also compared. Results There were no significant differences in body temperature between the three groups (P>0.05) . During the operation, the body temperature of the three groups decreased, and the recovery from the chest was restored. There were significant differences in body temperature between the three groups (P 0.05) . The coagulation and stress indexes of the observation group and the control group were significantly different from those of the normal group (P 0.05) . The coagulation, lactic acid and stress indexes of the three groups were significantly different before and after surgery (P<0.05) . There was a statistically significant difference in interleukin-6 (IL-6) levels before and after surgery (F=134.241, P< 0.001) ; there was an interaction between the intervention and the time, and the difference was statistically significant (Finteraction=12.202, P<0.001) . There were significant differences between the three groups in the interleukin-10 (IL-10) level group (between group F=7.792, P < 0.001) ; the difference of IL-10 levels before and after surgery was statistically significant (Ftime=112.121, P< 0.001) ; There was an interaction between the intervention and the time, and the difference was not statistically significant (Finteraction=2.990, P=0.055) . Conclusions Compared with patients with normal BMI thoracic surgery, patients with low BMI have abnormal blood coagulation and stress indicators before surgery, and are more likely to have intraoperative blood pressure drop and adverse reactions. Comprehensive intraoperative warming measures can effectively prevent hypothermia in patients with low BMI. Key words: Body mass index; Thoracic surgery; Body temperature; Coagulation function; Stress index

ИССЛЕДОВАНИЯ СОВМЕСТНОЙ РАБОТЫ ГЕНЕТИЧЕСКОГО АЛГОРИТМА И АЛГОРИТМА КООРДИНАТНОГО ПОИСКА ДЛЯ ОПТИМИЗАЦИИ ТЕМПЕРАТУРЫ ОТАПЛИВАЕМЫХ ПОМЕЩЕНИЙ

The article is focused on studying optimization algorithms that are relevant both for solving applied problems and for studying the artificial intelligence in general. Optimization methods are used to solve environmental problems including the issues of energy saving. It is important to solve problems of optimizing the thermo-hydraulic modes of buildings (as a part of the “Smart City” project), in particular, problems of eliminating temperature imbalance in terms of saving thermal energy and improving the microclimate in apartments. There is shown a mathematical formulation of the problem of optimizing the temperature modes of the indoor areas using adjustable devices. A hybrid algorithm applied to solve the problem has been described. The considered algorithm combines two optimization methods: a coordinate search method and a genetic algorithm. Thus, the stochastic component (element of the genetic algorithm) and the gradient component (element of the coordinate search method) are used in the hybrid algorithm. A description of the above algorithms is given including the mathematical apparatus used and the design formulas. The results of the numerical experiment for the suggested algorithm are presented. These results are compared with the results of applying the genetic algorithm and the method of coordinates search separately. There has been confirmed the hypothesis that in order to increase the efficiency of solving the considered class of problems, it is necessary to combine the genetic algorithm and gradient methods. At the same time, it has been inferred that in cases of low thermal power of radiators, optimization of the hydraulic resistance of valves is not sufficient, thermal insulation measures and replacement of radiators are also required. The practical value of the work lies in the possibility of solving the problem of saving thermal energy in the housing and communal services system.

Introduction in the Russian federation of international standards in the field of measurement and evaluation of sound insulation

The features of the introduction in the Russian Federation of international standards for measurement and evaluation of sound insulation are considered. Over the past eight years, a system for measuring and evaluating the sound insulation of buildings and their elements has been created on the basis of international standards. In 2012, a series of international standards ISO 10140 for methods of laboratory measurements of airborne and impact sound insulation was introduced as the national standards of Russia GOST R ISO. In 2016, the standards ISO 717 were introduced as modified national standards GOST R 56769-2015 and GOST R 56770-2015, setting the rules for single-number rating of airborne and impact sound insulation. In 2018, the international standard ISO 12999-1 was introduced as a modified national standard GOST R 57900-2017 for determining and applying the uncertainties in measuring sound insulation. In 2019, a draft national standard was prepared for field measurement of sound insulation of facades and their elements, which is a modified edition of the ISO 16283-3. Single-numeric parameters of airborne and impact insulation determined using these standards are subject to comparison with the normative values regulated by the national regulatory document—the set of rules SP 51.13330.

Massive or lightweight? Sound insulation of Austrian multistory apartment buildings since 2000

During the past centuries, Austria was a country of massive multistory apartment houses. Since the last decade of the last century, technical and legal developments led to experimental multistory buildings with lightweight construction as timber frame or cross laminated timber construction. During the following years, the proportion of lightweight constructions increased slightly. In Styria, a federal land in the south of Austria, it is usual to perform sample performance measurements also of the quality of subsidized apartment buildings upon competition. This paper shows some results of such quality measurements of airborne and impact sound insulation during the past two decades and discusses the performance of different constructions. Moreover, some results of “mikrozensus” surveys about noise pollution of the federal institution “Statistik Austria” are presented. The question arises, if the used descriptors as, e.g., the weighted sound reduction index Rw are still sufficient meaningful in every case or if there should be some additional information to avoid specific problematic construction solutions. Another way would be to provide rules for robust in detail. Some special cases and construction influences are shown exemplarily. For future development, it would be of interest to provide more information about sensitivity of construction measures in order to enhance the future sound insulation performance not only as a number but in reality.During the past centuries, Austria was a country of massive multistory apartment houses. Since the last decade of the last century, technical and legal developments led to experimental multistory buildings with lightweight construction as timber frame or cross laminated timber construction. During the following years, the proportion of lightweight constructions increased slightly. In Styria, a federal land in the south of Austria, it is usual to perform sample performance measurements also of the quality of subsidized apartment buildings upon competition. This paper shows some results of such quality measurements of airborne and impact sound insulation during the past two decades and discusses the performance of different constructions. Moreover, some results of “mikrozensus” surveys about noise pollution of the federal institution “Statistik Austria” are presented. The question arises, if the used descriptors as, e.g., the weighted sound reduction index Rw are still sufficient meaningful in every case or...

Measurement of low frequency impact insulation

The authors have proposed a dual-rating method for measuring impact insulation in which the high and low-frequency components of impact noise are evaluated independently [LoVerde and Dong, J. Acoust. Soc. Am. 141, 428–440 (2017)]. The measurement of low frequency impact sound in rooms is critical to determining human response and acceptability of floor ceilings. In this paper we discuss issues related to low frequency measurements in residential applications. The paper will include analysis of the suitability of the standard tapping machine as a source for low frequency impact noise for typical assemblies within North America. The authors will review the uncertainty of low frequency measurements in typical receiving rooms. The paper will discuss the measurement methodology as a requirement for adoption of a measurement standard.

Effects of comprehensive temperature preserving nursing on the levels of lactic acid in lung transplantation patients

Objective To explore the effects of comprehensive temperature preserving nursing on the body temperature and the levels of lactic acid in lung transplantation patients. Methods Totally 46 patients underwent lung transplantation were randomly divided into experimental group and control group, with 23 patients in each group. Comprehensive insulation nursing measures were implemented in the experimental group, and conventional insulation measures were used in the control group. The rectal temperature and arterial blood lactic acid values of the two groups were recorded and compared before anesthesia (T0), after chest opening but before pulmonary artery occlusion (T1), after pulmonary artery occlusion (T2), during new lung transplantation (T3), after pulmonary artery opening (T4) and after surgery (T5). Results There was no statistically significant difference in rectal temperature and blood lactic acid between the two groups before anesthesia (t=1.53, 0.61, P>0.05). The rectal temperature of the experimental group were (36.55±0.14), (36.42±0.160), (36.33±0.13), (36.15±0.11), (36.45±0.10) ℃, which was higher than that of the control group (35.69±0.17, 35.52±0.19, 34.61±0.17, 34.47±0.13, 34.79±0.18) (F=3.24, P 0.05). The lactate levels of experimental group at T2 and T3 was higher than that before anesthesia (F=1.33, 1.16, P 0.05).In the control group, the rectal temperature during each operation period was lower than that before anesthesia (F=1.17-2.51, P<0.01), and the lactic acid level was higher than that before anesthesia (F=0.51-2.25, P<0.01). Conclusion Comprehensive heat preservation nursing measures can maintain the relative stability of body temperature during lung transplantation, which is conducive to tissue perfusion and oxygenation. Key words: Comprehensive temperature preserving; Lung transplantation; Levels of lactic acid

Energy savings and risk of mold growth in apartments renovated with internal insulation

This article presents a project for renovation of a large residential area, where the focus is on moisture-safe internal insulation measures and the energy saving potential. Parts of two three-story houses were renovated with different combinations of capillary active insulation measures, including mechanical ventilation with heat recovery in one house. For two years, energy use for heating was measured, as well as temperature and relative humidity in the internal insulation, indoors, and outside. The insulation was dismantled in two apartments after 2 years, to test for mold growth at the original wall surface. Furthermore, the indoor climate and energy use for heating was measured in nine reference apartments. The inspection and mold measurements after the removal of the insulation material did not show signs of mold growth. Apparently, the used insulation material can be used in these specific cases without risk of mold growth. However, the relative humidity behind the insulation was measured at up to 90% in the first winter and decreased to 70% relative humidity in the next winter. There was good agreement between measured and calculated energy savings for heating; up to 24% savings was documented for the house with more far-reaching measures.

Hormigón infraligero: Listo para la práctica (English version)

Hormigón infraligero: después de diez años de investigación en la Technische Universität Berlin (TU Berlin) y tras la construcción de una vivienda piloto hace diez años como prueba de la eficacia de este innovador material, el hormigón infraligero está listo para la práctica. Los riesgos implicados que toda innovación lleva consigo son ahora previsibles. Para aquellos que quieran usar este hormigón estructural de alto rendimiento o investigarlo más a fondo, encontrarán en este artículo un resumen de lo más importante acerca de este material, el cual permite estructuras de hormigón visto que prácticamente no necesitan ninguna medida adicional de aislamiento térmico. Los resultados alcanzados hasta ahora por los autores y la investigación en curso son presentados en detalle. El diseño estructural apropiado con este material y su potencial de forma serán también discutidos, así como los requisitos necesarios para su aprobación, ya que su uso no está cubierto por los Eurocódigos. Finalmente, se presentan algunos edificios de hormigón infraligero construidos hasta ahora y otros que están siendo actualmente planificados.

A Transcriptomic Analysis Reveals Diverse Regulatory Networks That Respond to Cold Stress in Strawberry (Fragaria×ananassa)

Strawberry is often subjected to cold stress in temperate regions when insulation measures are not strictly applied in protected cultivation. Cold stress adversely influences plant growth and development by triggering a massive change to the transcriptome. To provide the potential strategies in improving strawberry cold tolerance and give a glimpse into the understanding of the complex cold signaling pathways in plants, this study identified attractive candidate genes and revealed diverse regulatory networks that responded to cold stress in strawberry (Fragaria×ananassa) by a transcriptomic analysis. Totally, there were 2397 differentially expressed genes (DEGs) under cold stress treatment (T1) vs. normal treatment (CK). Of these, 1180 DEGs were upregulated, while 1217 DEGs were downregulated. Functional enrichment analysis showed that DEGs were significantly (adjusted P value < 0.05) overrepresented in six pathways including plant hormone signal transduction, flavonoid biosynthesis, mitogen-activated protein kinase (MAPK) signaling, starch and sucrose metabolism, circadian rhythm, and alpha-linolenic acid metabolism. The cold signaling initiated expression of downstream cold-responsive (COR) genes with cis-acting element ABRE or CRT/DRE in the ABA-independent or ABA-dependent pathway to impel plant defense against the stress. Strikingly, GIGANTEA (gene id 101308922), two-component response regulator-like PRR95 (gene id 101295449), and ethylene-responsive transcription factor ERF105-like (gene id 101295082) were dramatically induced under low-temperature treatment, indicating that they played an important role in response to cold stress in strawberry.

Moisture-Resistant Sealing Materials for Downhole HPHT Electrical Feedthrough Package

Abstract A bismuth oxide–based multicomponent glass system, xH3BO3-yBi2O3-(1-x-y-δ)MO-δ· rare earth oxides (REOs) with MO = TiO2, BaO, ZnO, Fe2O3, etc., and lanthanum series–based REOs, for making downhole high-pressure and high-temperature electrical feedthrough package has been developed using high-temperature melt-quenching and sintering technologies. By properly controlling phase structures in material-manufacturing processes, the obtained sealing materials have shown moisture-resistant properties in their monoclinic and tetragonal mixed phase structures but strongly hydrophobic properties in their covalent bond tetragonal phase. Sealed electrical feedthrough packages have been evaluated under boiling water immersion and 200°C/30,000 PSI water-fluid–simulated downhole harsh environments. The post electrical insulation measurement has demonstrated to be greater than 1.0 × 1014 Ω electrical resistance. This article will show that such a high–bonding strength and high–insulation strength sealing material could be used to seal electrical feed-throughs and connectors for 300°C/30,000 PSI downhole and subsea wireline, logging while drilling, and measurement while drilling tools' signal, data, and electrical power transmissions.

Acoustic performance of noise barrier based on sonic crystals with resonant elements

Recent years have seen a growing interest in the potential for the use of sonic crystals as noise barriers. The frequencies of highest attenuation can be found by assuming that an integer number of half wavelengths fits the distance between the scatterers. However, this leads to a reduction in its usefulness as a viable noise barrier technology, due to the necessary increase in overall crystal size to increase frequency range of noise reduction. Additional attenuation bands may be achieved if the array is composed of resonant elements instead of solid cylinders. The paper presents resonant sonic crystal barrier that could be applied to stationary but movable noise sources eg. power generator. The results of simulation results were confronted with the results of previous work in this field. This work presents also sound insulation measurements conducted over sonic crystal noise barrier according to the European standard EN 1793-6. In most of the reference literature, sound insulation and reflection properties of sonic crystals are measured or a diffuse sound field or in a direct sound field including the top and side edge diffraction effects together with the transmitted (or reflected) components. The aim of this work is to perform free-field measurements over a real-sized sample in order to verify the points of strength and weakness of the application of standardised measurements to sonic crystals.

Experimental study of heat retention performance of thermal diode Integrated Collector Storage Solar Water Heater (ICSSWH) configurations

Integrated Collector Storage Solar Water Heaters (ICSSWHs) can support growing hot water demands of off-grid populations and reduce harm to human health and the environment. Despite their simple design and fewer associated components, stored thermal energy dissipates easily in foul weather. While thermal diodes are beneficial heat retention enhancement features in ICSSWHs, other simple additional strategies can enhance heat retention without significantly complicating the fabrication process. This article examines techniques of differing levels of complexity for the improvement of heat retention of a basic thermal diode ICSSWH. A basic thermal diode ICSSWH is adapted into a scalable Asymmetric Formed Reflector with Integrated Collector and Storage (AFRICaS) system and tested for heat retention performance along with other thermal insulation measures. The AFRICaS system improves heat retention efficiency and reduces heat loss coefficient to at least 35% and 1.46 W/K respectively. These results contrast with a heat retention efficiency and heat loss coefficient of 20% and 2.25 W/K respectively for a basic thermal diode ICSSWH. The AFRICaS prototype is potential launchpad for sustainable solar energy cogeneration.

Auditive Milieugestaltung in Einrichtungen für Menschen mit Demenz

This study examined the degree to which atmosphere, sounds or volume levels impact nursing home residents with dementia and employees. Research questions were how an auditory milieu is designed, how it can be positively redesigned and how this affects the employees and residents’ well-being. A pre/post mixed-methods design using the following methods was carried out: descriptions of atmosphere, measurements of volume level and reverberation time, record of sounds, questionnaire for employees and observation of the residents with dementia (Dementia Care Mapping). Between two research phases, further training for employees, technical changes and sound insulation took place. In the first research phase high volume levels and high reverberation times were measured and many technical sounds recorded. The auditory environment could be redesigned most effectively through the combination of further training, technical changes and sound insulation measures, as found in a second data collection.

Study on interference and protection of pipeline due to high-voltage direct current electrode

Abstract To study the rules of interference and protective measures on buried pipelines of high-voltage direct current (HVDC), the influence of different factors, including current into soil, soil resistance, damaged rate of coatings, and electrode-to-pipe distance, on pipe-to-soil potential deviation were simulated. Based on the simulated results, the fitted equations and interference judgment pattern were also obtained. The protective measures of insulation and cathodic protection can be performed for buried pipelines to prevent the interference, but the cathodic protection in the isolated area may become the stray current source of the other pipe section. This study can provide suggestions for the evaluation of interference and protective measures of pipelines of HVDC.

Design of a multi-layer insulation(MLI) measurement system with a G-M cryocooler

Multi-layer insulation (MLI) is widely used in cryogenic systems such as Aerospace propulsion systems and various cryostats. The effective thermal conductivity of MLI used in lab is measured by typical systems using bath cryostat, which is only able to maintain boundary temperatures at critical point of cryogen. A liquid cryogen-free apparatus based on a two stage G-M cryocooler has been developed to measure the effective thermal conductivity of multi-layer insulation(MLI) materials at temperatures ranging from 20-300 K. Unlike traditional measurement systems utilizing evaporation rate of liquid cryogen, a calorimeter supported by a calibrated rod is installed in this system to determine the heat flow through the testing blanket. This design eliminates the error caused by variation of environment pressure to the measured evaporation rate, and meanwhile, simplifies the system structure.

Excessive noise as a test for many-body localization

Recent experimental reports suggested the existence of a finite-temperature insulator in the vicinity of the superconductor-insulator transition. The rapid decay of conductivity over a narrow temperature range was theoretically linked to both a finite-temperature transition to a many-body-localized state, and to a charge-Berezinskii Kosterlitz Thouless transition. Here we report of low-frequency noise measurements of such insulators to test for many body localization. We observed a huge enhancement of the low-temperatures noise when exceeding a threshold voltage for nonlinear conductivity and discuss our results in light of the theoretical models.

Probabilistic assessment of the impact of material properties on the risk of frost damage in masonry constructions

Historically valuable buildings often contain a huge energy saving potential due to their current lacking thermal performance of the building envelope. Next to this, unfortunately insulation measures, which normally occur at the inside, induce a decrease in the temperature and drying potential of the structure which results in a risk for frost damage. To validate this risk Heat, Air and Moisture simulations are a valuable tool. Heritage facades often consist of masonries, which are known to have a complex hygrothermal behaviour. Therefore nowadays a homogenization of the masonry, for example to a homogenous brick wall, is often assumed to save computational time. Nevertheless these homogenizations, which include neglecting mortars, can have a drastic impact on the hygrothermal behaviour of masonries. Hence this study compares the impact of basic material parameters for the brick, pointing mortar and bed mortar of a masonry separately under a constant indoor and outdoor climate based on probabilistic simulations. The evaluation is done for three frost related criteria. Generally, the main impact parameters for the one and a half brick construction are found to be quite similar for interior insulated and not insulated cases but diverse between the chosen criteria.

Optimized reference spectrum for rating the impact sound insulation of concrete floors.

It has been long recognized that the single-number quantities presented in the standard ISO 717-2 [(2013) International Organization for Standardization] do not correlate especially well with the subjective judgment of living impact sound sources directed to the floors. The aim of this study was to find single-number quantities which are well associated with the subjective annoyance caused by different impact sounds. Experimental data of laboratory measurements of impact sound insulation of floors and a psychoacoustic experiment was used [Kylliäinen et al. (2017). Acta Acust. Acust. 103, 236-251]. The five studied impact sound types were walking with hard shoes, socks, and soft shoes, super ball bouncing, and chair moving. A fundamental requirement was that the single-number quantities can be expressed as the sum of L'n,w or L'n T, w and a spectrum adaptation term. Reference spectra were derived by the means of a mathematical optimization method. Reference spectra for each sound type were defined separately. An optimized reference spectrum based on all five sound types explained the annoyance of these sound types reasonably well (r2 = 0.93) and better than any of the standardized single number quantities (e.g., r2 = 0.86 for L'n,w + CI,50-2500).

Numerical simulation and analysis of the temperature effect on the fission of concrete

In order to further improve the crack resistance of concrete engineering, a numerical simulation method is constructed to study the effect of temperature on the fission of concrete. Based on the finite element method, the mathematical model is constructed, and the numerical calculation and image display are used to simulate and analyze the engineering problems. The temperature sensor is used to observe the whole variation law of typical temperature field, and the temperature of concrete entering and pouring is obtained. Thus, the temperature control real-time automatic acquisition system is set up. According to the temperature field and temperature stress distribution rules, the ideal temperature control curve model of concrete is proposed. Finally, the numerical calculation and experiment of the model are carried out. The results show that the maximum surface stress level decreases in varying degrees after different surface insulation measures are taken, and if the thermal insulation material?s ? ? 10 kJ/m2h?, the maximum surface stress of concrete can be reduced to 0.06~0.14 MPa. In this paper, it is shown that the negative effect of the large diurnal temperature difference on concrete surface insulation can be controlled.