This paper presents the testing of the durability of concrete where a part of cement was replaced with ground panel cathode ray tube glass (CRT) finer than 63 µm. The percentage of cement replaced with glass is 5%, 10%, 15%, 20%, and 35%, by mass. The highest percent share of mineral admixtures in CEM II (Portland-composiste cement) cement was chosen as the top limit of replacement of cement with glass. In terms of the concrete durability, the following tests are performed: freeze-thaw resistance, freeze-thaw resistance with de-icing salts-scaling, resistance to wear according to the Böhme test, sulfate attack resistance, and resistance to penetration of water under pressure. A compressive strength test is performed, and shrinkage of concrete is monitored. In order to determine the microstructure of concrete, SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analyses were performed. The obtained research results indicate that the replacement of a part of cement with finely ground CRT glass up to 15% by mass has a positive effect on the compressive strength of concrete in terms of its increase without compromising the durability of concrete. The results obtained by experimental testing unequivocally show that concrete mixtures made with partial replacement (up to 15%) of cement with finely ground CRT glass have the same freeze-thaw resistance, resistance to freeze/thaw with de-icing salt, resistance to wear by abrasion, and resistance to sulfate attack as the reference concrete. In terms of environmental protection, the use of CRT glass as a component for making concrete is also very significant. It is well known that different waste materials are very successfully implemented in the contemporary construction industry. To date, extensive research on fly ash, blast furnace slag, and silica dust use, as well as on mineral admixtures when making concrete and concrete prefabricates, has been conducted. The potential to use waste glass, including cathode ray tube (CRT) glass, for making of new products or as an admixture to the existing ones is being intensively investigated. This kind of research intensified particularly in the period after CRT TV sets and computer monitors were replaced in the market by the advanced technology of thin film transistor (TFT) and liquid crystal display (LCD) screens. Cathode ray tube glass represents a considerable part of electronic waste (e-waste). E-waste globally increases at a far higher rate than other solid waste materials. According to the data of the United Nations University, in 2018 solely, a total of 49.8 million tons of e-waste was generated in the world, CRT comprising a considerable part of it . In thatOne possibility to use waste glass is to replace a part of the natural aggregate for concrete making ,7,8,9,102 emissions. Previous research determined that grinding the glass with a high content of amorphous silicon into a fine dust (particles finer than 100 µm) activates its pozzolanic reactivity, which is the basic precondition for its use as a supplementary cementitious material [The other option is the use of finely ground waste glass as a substitution for part of the cement, supplementary cementitious material (SCM), when making concrete. Such use of waste glass would have both economic and environmental benefits considering that cement-producing industries emit almost 7% of the total amount of global COmaterial ,20,21,22material  determinmaterial , it was material  determinmaterial  producedIn the research of the use of CRT glass as SCM, special attention is paid to the durability of such cement composites. Papers ,30,31,32Based on the review of a large number of papers, only some of which have been mentioned in the introduction, it can be concluded that only a small number of researches on the durability of concrete were performed with finely ground CRT glass. One of the goals set for this research is proving the potential use of CRT recycled glass as a partial replacement for cement in concretes, which are expected to have the same durability properties as the reference concrete. Moreover, the goal of this experimental research is to determine the ultimate percentage of replacement of cement with finely ground CRT glass, where the durability properties of concrete are at such a level to allow their practical use. In order to achieve the set goals, we conducted very extensive and comprehensive research that lasted several years. In this paper, we presented the research results referring only to the durability of concrete, and for that purpose solely, 350 concrete test specimens were made. The basic motivation for conducting this study is solving the problem of CRT glass disposal, which is a severe environmental problem that can, to a great extent, be solved by proving it can be used as a component of concrete. The importance of the study is reflected in the successfully proven potential for the use of CRT as a replacement for cement while even making certain economic gains. Namely, the practice up to date in Serbia is that the collected CRT glass is exported to other countries and the countries taking in the recycled CRT glass are paid for that.The experimental research presented in this paper is directed towards testing the durability of concrete where a part of cement is replaced by finely ground panel CRT glass. In terms of concrete durability, the following tests are conducted: freeze-thaw resistance, freeze-thaw resistance with de-icing salts-scaling, resistance to wear according to the Böhme test, sulfate attack resistance, and resistance to penetration of water under pressure. Additionally, the compressive strength is measured and the shrinkage of concrete is monitored. For the purpose of observing the concrete microstructure, SEM and EDS analyses are performed.3 and the Blaine specific area of 245 m2/kg, which is around 40% less than the cement. The particle size distribution of cement and ground CRT glass is presented in Portland cement CEM I 52.5R  is used for making the concrete mixtures, according to standard EN 197-1. Panel CRT glass is taken from the recycling center of Niš, Serbia. Large shards of CRT glass are ground using the laboratory ball mill so that the glass particles are finer than 0.063 mm. The physico-chemical composition of finely ground CRT glass and cement is presented in In the experiment three fractions of river aggregate are used . The particle size distribution of aggregate fractions is determined using the dry sieving method according to EN 933-1 and shown in slump 100–130 mm) of fresh concrete, tested according to the standard EN 12350-2. The shares of individual fractions of aggregate in the mixture are 43% (fraction 0/4 mm), 23% (fraction 4/8 mm), and 34% (fraction 8/16 mm). Reference concrete is made with 400 kg of cement and 1800 kg of three-fraction aggregate. The water/binder ratio (w/b) is constant and amounts to 0.438. Superplasticizer on the basis of polycarboxylate is used for making the concrete mixes, which reduces the amount of water. The percentage of cement replaced with CRT glass amounts to 5%, 10%, 15%, 20%, and 35%, compared to the mass of cement. The highest percent of the share of mineral admixtures in CEM II cement was chosen as the top limit of replacement of cement with glass. The markings of concrete mixtures are made corresponding to the percentage of cement replacement  is made with fine river aggregate and cement, with no addition of glass. In mortar WG1, 35% of cement is replaced by CRT glass having fineness 0.063/0.090 mm, while in mortar series WG2, 35% of cement is replaced by the ground CRT glass finer than 0.063 mm. The goal of the research is to check the alkali-silicate reactivity of CRT glass in a mortar and to investigate the effect of the fineness of glass on the intensity of ASR. Such a percentage of cement replaced with finely ground CRT glass is chosen because it is later found to be the highest percentage of cement replaced in concrete. The other reason is the assumption that the potential ASR will be more manifest if the replacement of cement is 35% in comparison to the lower percentages of replacement.Prior to the test, nine specimens of concrete in the shape of a cube having a side of 150 mm, 28 days old, are immersed in water having a temperature of +20 ± 3 °C until saturated. After that, they are exposed to 200 cycles of subsequent freezing and thawing. One cycle consists of freezing the specimens at the temperature of −20 ± 2 °C for 4 h and thawing in the water having temperature +20 ± 3 °C for 4 h. According to the standard SRPS U.M1.206 , concretThe compressive strength of the frozen specimens is tested after the completed 200th cycle, and the reduction in the compressive strength of concrete is calculated in comparison to the reference specimens cured in water to the equivalent age according to the formula:—the reduction in compressive strength of concrete after 200 cycles of freezing in %.Freeze-thaw resistance with de-icing salts-scaling is estimated by measuring the mass of the material scaled from the surface of the samples after 28 cycles of freezing and thawing. After 7, 14, and 28 cycles, visual inspection of samples is performed, scaled material is collected, its quantity measured, and replacement of the 3% solution of NaCl is performed.sc (t), caused by the shrinkage of concrete in the air, is calculated in relation to the first-initial measurement after 72 ± 0.5 h.Concrete shrinkage testing is performed according to the standard UNI 6555  on concr2SO4 until the moment of testing. The entire 5% solution of Na2SO4 in the curing vessels is replaced in a way to retain the pH value of the solution. The pH value of the Na2SO4 solution is je ~7.5, i.e., ~12.5 in the case of saturated lime water. Sulfate attack resistance of concrete series with added CRT glass is determined by comparing the compressive strength of reference samples of each series with the samples exposed to the sulfate attack after the exposure of concrete to the sulfate solution in the duration of 3, 6, and 12 months. Testing of the compressive strength was conducted according to the standard ASTM C1231-14 [Each concrete series comprises 18 samples of cylinder-shaped specimens having a diameter of 100 mm and a height of 100 mm. Half of all specimens are reference specimens that are cured in saturated lime water until the moment of testing. The other half of the specimens are, at the age of 28 days, immersed and maintained in a 5% solution of NaC1231-14 . Apart fSEM and EDS analyses are performed in order to acquire knowledge of the concrete microstructure. All concretes are observed and analyzed, but this paper displays only the samples representing the following concrete series: reference, WG15 and WG35. The age of the samples during the analysis of the microstructure is 90 days.3) and finely ground CRT glass (2.84 g/cm3) has not had a considerable impact on the change of density of fresh concrete. This can be explained by the fact that when replacing cement with 35% of glass, it constitutes only around 5% of the concrete volume and therefore cannot have a considerable impact on the variation of density. The content of entrained air in concrete mixtures ranges between 3.0% and 3.6%  in the standard SRPS U.M1.206 [U.M1.206 .Kim et al.  tested tThe highest value of penetration of water under pressure is measured in WG20 concrete, but it was only 20 mm . The serThe effect of the presence of ground CRT glass on the resistance to wear by abrasion is shown in A graphical presentation of the impact of the replacement of cement with finely ground CRT glass in concrete on the water absorption is presented in 2 (pH = 12.5) and of the samples cured in sodium-sulfate solution (pH = 7.5) at the ages of 3, 6 and 12 months. Not even after curing samples in a 5% solution of Na2SO4 for a year, has there been any variation of compressive strength higher than 10%, compared to the samples cured in calcium-hydroxide (reference samples). The highest reduction in compressive strength is determined by the reference concretes, which have no CRT glass added, and it is 10.01%. As can be seen in After the very impact of the presence of CRT glass on the compressive strength of concrete has been defined (3.2), one can observe the resistance to sulfate attack of the experimental concrete. SEM and EDS analyses were conducted on the specimens of all experimental concrete series, while in the following text, only analyses referring to pure ground CRT glass, WG15, and WG35 are presented. Microscopic observation of finely ground CRT glass a revealsOn the observed concrete samples, SEM and EDS analyses do not indicate the presence of an undesirable alkali-silicate reaction, more precisely the A-S-R gel, which is in agreement with the results of the experimental tests of this phenomenon.Replacement of a part of cement with finely ground CRT glass in the amount of 5% has a negligible impact on the compressive strength of concrete, while replacing cement with 10% and 15% of ground glass has a positive effect on the mechanical strength of concrete, as it increases it. The replacement of cement in the quantity of 20% has practically no impact on the variation of compressive strength in comparison to the reference concrete, while the replacement in the amount of 35% has a considerable effect on compressive strength by reducing it in comparison to the reference concrete (around −25%).The durability of concrete, in terms of the properties which were tested and whose results were presented in the paper, corresponds to the durability of the reference concrete up to the quantity of 15% of CRT glass replacing the cement. The concretes in which cement was replaced with glass in the amount of 20% reached the ultimate values in terms of resistance to freeze-thaw action and simultaneous action of freezing and defrosting salt. This makes their use problematic and questionable in the conditions where they undergo such influences, and their use cannot be recommended. Finally, concrete mixtures with the highest replacement of cement with CRT glass in the amount of 35% did not exhibit satisfactory durability.In general, based on the presented results of experimental research, it can be concluded that concrete composition with replacement of a part of cement with finely ground CRT glass up to the amount of 15% meets the requirements for practical use of concrete which is exposed to the aggressive impacts of the environment.A very important reason for using ground CRT glass as a cementitious material in practice is environment protection and solving the hazardous waste disposal matter. The amount of CRT glass that is still present and which is being collected by the recycling centers worldwide is remarkable and cannot be neglected. On the other hand, the production of cement concrete as the most used material in civil engineering is more than adequate to use up the entire available CRT glass as a replacement of a part of cement. Of course, it requires a certain investment, for instance, in the CRT glass mills, transport, storage, but its contribution to the protection of the environment is far more important.


We compare the results obtained via structural and morphological analysis to the Electrochemical Impedance Spectroscopy (EIS) measurements performed on the button cells, disentangling the role of different parameters. The Atomic Force Microscopy analysis makes it possible to observe a decrease in the roughness values from the peripheral to the central zones under the sputtering target, with peak-to-valley roughness values, respectively, decreasing from 380 nm to 300 nm, while Scanning Electron Microscopy and Energy Dispersive Spectroscopy show a dependence of the layer coverage from the position. The electrochemical performances of button cells with buffer layers of only 200 nm in thickness, and with negligible thickness gradients across them, show current density values of up to 478 mA/cm2 at 0.8 V and 650 °C, with an improvement of more than 67% with respect to button cells with standard (screen printed) buffer layers. These results point out the major influence exerted by parameters such as the thickness gradient and the coverage of the sputtered buffer layers in determining the final electrochemical performances.We investigate the influence of position, under large circular sputtering targets, on the final electrochemical performance of 35 mm diameter button solid oxide fuel cells with sputter-deposited Gadolinium doped Ceria barrier layers, positioned in order to almost cover the entirety of the area associated with a 120 × 80 mm The lowering of the working temperature of Solid Oxide Fuel Cells (SOFC) down to the intermediate temperature (IT) range is, at present, crucial for the widespread use of this energy technology. The use of Doped Ceria (DC) barrier layers between the cathode and the electrolyte can improve the SOFC’ efficiency even if the working temperature lowers to the IT range 500 °C–700 °C) ,2,3,4. T00 °C ,2,2. We adopted a simple approach in which the DC barrier layer was deposited on six half (anode plus electrolyte) button cells, which were distributed under the sputtering target in order to almost cover the entirety of the area associated with a standard industrial cell . The sputtering target dimension, the plasma active area, the target–substrate distance, the partial pressure of the operating gas  and the power applied to sustain the discharge are the parameters that typically influence the thickness and the density’s homogeneity during the sputtering process. In the case of the system used for this experiment, previous studies made it possible to select these parameter values in order to optimize the homogeneity and the density of the deposited DC layers on a 35 mm diameter circular SOFC [The investigated samples were fabricated through the use of the magnetron Radio Frequency (RF)-Sputtering device  based at the University of Salerno endowed with a 150 mm diameter target: Gdlar SOFC ,8. The t−1∙cm−2 of hydrogen and 40 Nl∙min−1∙cm−2 of air. AFM analysis made use of a Nanite  equipped with a Tap190Al-G monolithic silicon Tip ; measurements were performed in tapping mode with a 48 N/m constant force and 190 KHz resonance frequency. The AFM images had a 0.3 nm z resolution and a 1.5 nm xy resolution. Systematic XRD characterization was performed on as-grown and post-growth annealed sliver samples using a D2-Phaser Diffractometer . The diffractometer was endowed with a Cu-α radiation source characterized by a ribed in , after tribed in . The j-V2, preliminary investigations about the thickness profile and uniformity over the whole surface interested in the process are required. We, therefore, initially placed eight 8YSZ single crystal substrates , (111) oriented, 10 × 10 mm2 single-side polished) along the RF-Sputtering sample holder diameter, as shown schematically in When depositing onto a large area, as in the case of standard industrial cells depositing on an area of 80 × 120 mmThe blue solid line, shown in on plume , which won plume ). Here, 2 industrial cell. As it is clear from 2 cell  of around 400 nm and a root mean square average roughness (Rq) of 100 nm. In z and Rq of The surface morphology of the samples was investigated by means of AFM measurements. In To obtain complementary information on the composition and morphology of the sputter-deposited barrier layers, control silvers were inspected by Scanning Electron Microscopy (SEM) combined with Energy Dispersive Spectroscopy (EDS).As a first step, we analysed the anode-electrolyte substrate. Representative SEM images taken with the SE detector in plan view and in tilting condition are shown in In the Sampling different zones of the investigated slivers using SEM, we observed a tendency to present larger areas without a good DC coverage when going from sliver 200 to sliverIV and sliverIII. The SEM analysis was performed on the samples a few months after the sputter deposition. The differences in the observed coverage, therefore, could have been related to the sample position under the sputtering target and, in particular, to the presence of different strains acting on the DC layers, which was likely due to differences in thickness and grain dimension. From all of the structural and morphological analyses performed on the cells and the slivers, we concluded that the desired DC phase was obtained in all of the samples independently of the specific position under the sputtering target. On the other hand, this position played a role in the observed surface roughness and buffer layer covering. In As is clear from the figure, the relative performance of the cells differed considerably with current values taken at 0.8 and 0.9 V, varying by more than a factor of two. At all of the temperatures, among cells 1–6, cell 2 was the one with the best performances. At 750 °C, the j values of cells 3 and 6 were very close and were the lowest observed. By decreasing the working temperature, they continually showed the worst performances even though their respective j values were increasingly different, with cell 6 always performing better than cell 3. A similar behaviour was observed for cells 1 and 4, with j values of cell 1 always being higher than those obtained for cell 4. At all of the temperatures, the performances of cell 6 and cell 1 were better than those of cell 3 and cell 4, probably indicating a slight asymmetry, with respect to the centre, in the positioning of the cells and/or in the sputtered material flow. The performances of cell 4, cell 6 and cell 3 were always worse than those of the Reference cell. Cell 1 had j values that were slightly lower than those of the Reference cell at 700 °C and 750 °C, but showed higher values at 650 °C. Looking at the positions of the cells under the sputtering target, as shown in In We point out that, according to the data in The electrochemical characterization was completed by performing Electrochemical Impedance Spectroscopy (EIS) measurements at the same set of three different working temperatures, at 800 and 900 mV.In the following, as an example, the Nyquist plots for each sample at 900 mV, as shown in HF) and low frequency (RLF) resistances along with the polarization resistances (RP) . The results are reported in Using the data contained in the Nyquist plots, we calculated the high (RHF measured on the cells with DC-sputtered buffer layers were generally lower than those on the REF cells, due to the overall reduction in thickness. The values of RLF and RP instead followed the behaviour already observed in the j-V curves. Similar behaviours were also observed in the Nyquist plots at 800 mV. In As expected, the values of RLooking at the Bode plots of the impedance’s modulus, we obtained further confirmation of the behaviours already observed in the case of the j-V curves, with cell 2 always showing a lower value of the impedance modulus when compared with the reference sample, while the other cells were always characterized by higher values. On the other hand, for the impedance’s phase, we note the presence of a remarkable increase in the phase’s values at high frequencies, in the case of cell 1, 3, 4 and 6, while this was not observed in cell 2 and cell 200. This increase, more pronounced at lower temperatures, was generally associated with inductive effects, and again, its observed occurrence in cells with less uniform thickness and coverage could be traced back to more disordered paths followed by the charged species when passing through the cell, particularly in the DC buffer layer. Similar results were also observed in the Bode plots at 800 mV.The analysis of the j-V and EIS measurements, when compared with the results of the structural and morphological characterization, reveal that the specific position under the sputtering target, in the large deposition area investigated, influenced the final performance of the cells. In particular, our experimental results indicate that a major role was played by the uniformity and coverage of the DC thickness, while the surface roughness and absolute thickness values of DC seemed to have minor importance in relation to the determination of the electrochemical cell properties. The observed results are of relevance in terms of the further industrial scaling up of this technique. In particular, the minor role played by the absolute thickness value opens up the possibility of important decreases in the deposition process time.The room temperature RF-sputter deposition of the DC barrier layer in solid oxide fuel cells, over a large area, was investigated by positioning six half button cells under a 150 mm diameter sputtering target in order to almost cover the entirety of the area associated with a standard industrial cell. The cells with sputter-deposited DC layers were structurally and morphologically characterized using XRD, AFM, SEM and EDS measurements. The electrochemical properties of the cells were analysed using j-V and EIS measurements. From the structural and morphological analysis, we observed that, while the DC stoichiometric phase was equally present in all of the cells, their surface roughness, thickness and thickness gradient varied as a function of their position. The cross comparison of the structural and morphological investigation with the electrochemical results provided further evidence of the influence of the cells’ position under the sputtering target on their final performances. In particular, by also analysing the results obtained on a cell with a DC layer of only 200 nm thickness, we were able to disentangle the role played by the different parameters in the final performance of the cells. The gradient and coverage of the DC thickness seemed to be the major aspects that influenced the electrochemical properties, while the surface roughness and the thickness appeared to play only minor roles. These results represent important insights in view of the industrial scaling up of the investigated deposition technique and, in particular, for the design of a specific industrial sputtering system dedicated to the SOFC production.


The aim of this work was to study the effect of molecular hydrogen on oxidative processes in cardiac surgery patients with acquired valve heart disease applied during surgery under cardiopulmonary bypass (CPB).The study involved 20 patients (16 men and 4 women) with acquired heart valve disease who were operated on under CPB. Two groups of patients were formed. In group 1 (n=11), anesthesia included inhalations of molecular hydrogen, which was supplied to the breathing circuit of the ventilator at a concentration of 1.5–2.0% immediately after tracheal intubation and throughout the operation. In group 2 (n=9), inhalation of molecular hydrogen was not performed. Blood sampling was taken at 4 stages: immediately after anesthesia induction, before CPB and after its termination, and also one day after the operation. The intensity of the processes of lipid peroxidation was evaluated by the level of diene (DC) and triene (TC) conjugates, Schiff bases (SB).In the patients of group 1, the arterial blood samples showed a decrease in the level of TC and SB, as compared to the first stage of the study, before the initiation of CPB and one day after the operation. An increase in the level of DC and TC was detected after the termination of CPB (p<0.05). In the venous blood samples, an increase in the level of DC was noted before the initiation of CPB, which was restored by the third stage of the study (p<0.05). At the same time, after the termination of CPB, a tendency towards a decrease in TC and SB was observed, which persisted one day after the operation.In the patients of group 2, an increase in the concentration of SB in the arterial blood samples was recorded during the study as compared to the first stage. The level of TC and SB in the venous blood samples increased one day after the operation.Intraoperative inhalation of molecular hydrogen leads to a decrease in the oxidative stress manifestation, it being most pronounced one day after the operation. This suggests that molecular hydrogen can be used in cardiac surgery as an effective and safe antioxidant. In the modern world, in the countries with high and average living standards, diseases of the cardiovascular system are the leading cause of a decrease in the quality of life and mortality. Among them, a special place is occupied by acquired heart valve diseases that develop as a result of acute and chronic diseases and lead to a violation of intracardiac hemodynamics  which, i–) without affecting less active signaling molecules [Numerous publications indicate that molecular hydrogen reduces oxidative stress both through direct reactions with strong oxidants  and indiolecules ; 3) beinolecules .The modern concepts suggest that the main predictor of the development of unfavorable adverse outcomes in the patients after cardiac surgery is the cytotoxic effect of reactive oxygen species (ROS) that is the oxidative stress due to the imbalance between the level of synthesized ROS and the ability of the redox system to level its growth. That is why the study of the role of oxidative stress in the pathogenesis of ischemic and reperfusion injuries in cardiac surgery and the search for methods for leveling these processes are highly relevant. The effect of molecular hydrogen on dynamics of oxidative processes during heart surgery has not been studied to date.The aim of this work was to study the dynamics of oxidative parameters of blood plasma against the background of inhalation of molecular hydrogen in the process of anesthesia during the surgical correction of acquired heart valve disorders under cardiopulmonary bypass (CPB).The study included 20 patients with acquired heart valve disease (16 men and 4 women) who were operated on under cardiopulmonary bypass in the Specialized Cardiosurgical Clinical Hospital named after Academician B.A. Korolev. The mean age of the patients was 57.6±7.8 years.2 hydrogen generator  and supplied to the respiratory circuit of the ventilator at a concentration of 1.5–2.0% immediately after tracheal intubation and throughout the operation. Group 2 consisted of 9 patients who did not receive hydrogen inhalation. The severity of the patients’ condition was determined according to the classification of the New York Heart Association (NYHA). The overwhelming majority of patients in both groups were assigned to functional class III: 9 out of 11 subjects in group 1 and 6 out of 9 subjects in group 2.The patients were divided into two groups. Group 1 consisted of 11 subjects, who were given anesthesia with inhalation of molecular hydrogen. The latter was obtained using a Bozon-H HThe mean CPB time was 74.3±25.8 min in the patients of group 1 and 76.1±27.3 min in the patients of group 2. The mean time of aortic cross-clamping was 67.2±18.2 and 60.2±13.2 min, respectively .The groups did not have significant differences in age and sex, severity of the condition, the nature of the surgical intervention, CPB duration, and aortic cross-clamp time. All the patients received standard premedication with diazepam (0.15 mg/kg) intramuscularly 30 min before surgery. Anesthesia was induced by a combination of diazepam (0.2–0.3 mg/kg) and propofol (2 mg/kg). Anesthesia was maintained at all stages of the operation using sevoflurane, an inhalational anesthetic. Fentanyl was used as an additional analgesic component. Myoplegia was maintained with Arduan at a dose of 0.1 mg/kg.The study was approved by the Ethics Committee of the Specialized Cardiosurgical Clinical Hospital named after Academician B.A. Korolev , in compliance with the World Medical Association Declaration of Helsinki “Ethical principles for medical research involving human subjects” and the requirements stated in the main regulatory documents of the Russian Federation on clinical trials. Written informed consent was obtained from all the patients.st — immediately after the induction of anesthesia; 2nd — before CPB initiation; 3rd — after the termination of CPB, 4th — one day after the operation. We studied the intensity of LPO processes by the contents of diene (DC) and triene (TC) conjugates, Schiff bases (SB) in blood plasma, which were determined by the method of I.A. Volchegorsky (1989). A heptane-isopropanol mixture (1:1) was added to the plasma, shaken, then 1 ml of an aqueous solution of hydrochloric acid (pH 2), and 2 ml of heptane were added. After settling and stratification into phases of the resulting mixture, the optical densities (E) were measured on an SF-2000 spectrophotometer , evaluating each phase at wavelengths of 220 nm (absorption of broken double bonds), 232 nm (absorption of DC), 278 nm (absorption of TC), 400 nm (absorption of SB).Blood sampling was taken at 4 stages of the operation: 1The obtained data were processed using the BIOSTAT  and Microsoft Excel  software packages using one-dimensional statistical models. The Shapiro–Wilk test was used to check the hypothesis about the type of distribution. The statistical patterns in the samples were studied with the parametric Student’s t-test since a normal distribution was shown. The parameters such as the arithmetic mean of the sample population and the standard deviation were calculated according to the Student’s t-test. The differences were considered significant at a significance level of p<0.05.st stage, most significantly at the 2nd stage, before CPB initiation.In the course of the study it was revealed that when molecular hydrogen was used in arterial blood samples before the initiation of the cardiopulmonary bypass procedure and one day after the operation, a decrease in the levels of TC and SB as compared to stage 1 was observed, although the levels of DC and TC increased after the termination of cardiopulmonary bypass , Table 2It should be noted that SB are formed by the covalent bond formation between LPO secondary products and the N-terminal residues of amino acids, proteins, and amino groups of phospholipids, and they also enter into polymerization and polycondensation reactions. Then the functional properties of the membranes are lost in this case, their destabilization occurs that results in cell destruction .nd stage of the study, it decreases by the 3rd stage, with subsequent decrease one day after the operation (rd stage), a tendency to decrease in DC and SB was observed. This tendency persisted one day after the operation. In group 2, the level of TC and SB, on the contrary, increased one day after the operation, significant changes occurring in SB on the first day after the operation.The analysis of the dynamics of the venous blood showed that, at the application of hydrogen, despite an increase in the DC level at the 2peration , Table 3The normal LPO intensity is known to meet the requirements of cellular metabolism, ensuring the vital activity of cells and their normal functioning. The excessive activation of these processes leads to membrane damage and is observed during the development of pathology . The ana–) with molecular hydrogen [When discussing the mechanisms of hydrogen action, it should be mentioned that there is a possibility of direct reduction of hydroxyl radicals (•OH) and peroxynitrite  or nitrosated (–S–NO2). Therefore, a decrease in –О– NO2 or –S–NO2 can regulate various gene expressions.ONOO studies , 16 haveMoreover, hydrogen reduces oxidative stress not only directly but also indirectly stimulating the growth of components of the antioxidant system, including heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase, and myeloperoxidase . The eryThus, the results of the arterial and venous blood tests demonstrate that the concentration of LPO products in the postoperative period in the first (main) study group decreases due to the direct antioxidant effect of molecular hydrogen and possible indirect effect through the modulation of the concentration of reactive oxygen species, which are natural signaling messengers, and they are essential for the regulation of cell activity.The results obtained suggest that intraoperative inhalations of molecular hydrogen can be used in cardiac surgery as an effective and safe antioxidant.


To evaluate the anatomical variations of the attachment of the inferior glenohumeral ligament (IGHL) to the anterior glenoid rim.This was a retrospective review of 93 magnetic resonance arthrography examinations of the shoulder. Two radiologists, who were blinded to the patient data and were working independently, read the examinations. Interobserver and intraobserver agreement were evaluated. The pattern of IGHL glenoid attachment and its position on the anterior glenoid rim were recorded.In 50 examinations (53.8%), the glenoid attachment was classified as type I (originating from the labrum), whereas it was classified as type II (originating from the glenoid neck) in 43 (46.2%). The IGHL emerged at the 4 o’clock position in 58 cases (62.4%), at the 3 o’clock position in 14 (15.0%), and at the 5 o’clock position in 21 (22.6%). The rates of interobserver and intraobserver agreement were excellent.Although type I IGHL glenoid attachment is more common, we found a high prevalence of the type II variation. The IGHL emerged between the 3 o’clock and 5 o’clock positions, most commonly at the 4 o’clock position. Lesions associated with anterior traumatic shoulder dislocation include bone fractures, such as Hill-Sachs and Bankart lesions, and soft tissue injuries, such as cartilaginous Bankart lesion and its variants. Other shoulder lesions, such as those involving the inferior glenohumeral ligament (IGHL), have also been described in the literature.Traumatic shoulder instability is a common condition, with an estimated prevalence of approximately 2% in the general population. Variations of IGHL lesions described in the literature include avulsion of a bone fragment off the humeral attachment, known as bony HAGL, avulsion of the humeral and glenoid attachments, known as a floating IGHL, and injury associated with posterior dislocation, known as reverse HAGL,6. Other possibilities are isolated avulsion of the IGHL off the glenoid rim without lesion of the anterior glenoid labrum, which can be related to detachment but does not involve a tear of the capsular-ligamentous or periosteal complexes,7, known as anterior labroligamentous inferior periosteal sleeve avulsion (ALIPSA), or complete capsular-ligamentous avulsion with periosteal tear,3, known as glenoid avulsion of the glenohumeral ligament (GAGL), although there is some controversy over these definitions.Humeral avulsion of the glenohumeral ligament (HAGL) reportedly occurs in up to 9.3% of cases of traumatic shoulder dislocation,9, variations of the IGHL attachment to the anterior glenoid rim are less common research topics. Most studies in the radiology literature provide only a generic description of the glenoid attachment of the anterior and posterior bands of the IGHL, stating they emerge from the labrum at the middle and lower thirds of the glenoid,10-15 or simply from the glenoid rim,17, and rarely do we find a more detailed description stating that they originate from the glenoid rim, labrum, and periosteum. However, anatomical studies indicate greater variability in the pattern of IGHL glenoid attachment, which can originate from the chondrolabral complex or directly from the glenoid rim,19, what Eberly refers to as type I and type II glenoid attachment, respectively. During arthroscopy, it is common to find that the IGHL and the chondrolabral junction cannot be clearly separated at the anteroinferior glenoid rim, a variant known as the labral-ligamentous complex.While the imaging features of some anatomical variations of the labral aspect or in different capsular, tendinous, and perilabral shoulder attachment patterns, such as the biceps-labral complex, are well-known and have been intensively studied,7,21,22, although MR arthrography is considered the gold standard for the preoperative assessment. To our knowledge, there have been no imaging studies aimed at assessing the different patterns of IGHL attachment to the glenoid rim, which could help in the interpretation of this complex anatomy and the associated lesions.Several imaging methods can contribute to the diagnosis of lesions associated with traumatic dislocation, including conventional X-ray, conventional magnetic resonance imaging (MRI), magnetic resonance (MR) arthrography, and even ultrasound,24. Diagnosing such a lesion with MR arthrography is considered challenging, and some authors argue that the most appropriate arthroscopic approach for diagnosing and assessing the extent of the lesion is the anterior portal. A better understanding of the anatomy of the IGHL, combined with the recognition of the different patterns of glenoid attachment, improves the diagnostic capacity of MR arthrography. In addition, details about the lesions obtained during the preoperative assessment with MR arthrography can facilitate the choice of the appropriate surgical techniques and lead to better treatment outcomes.Although an isolated lesion of the IGHL glenoid attachment is rare, it is important to recognize it because, when found in arthroscopies of patients with traumatic shoulder instability, it requires fixation, even if the fibrocartilaginous labrum is intactIn light of this, the objectives of this retrospective study were to assess MR arthrography examinations of the shoulder in order to characterize the anatomy of the IGHL attachment to the glenoid rim. We also evaluated the interobserver and intraobserver agreement for the findings.This was a retrospective study carried out in the radiology and diagnostic imaging department of the university hospital of our institution. The study was approved by the research ethics committee of the institution (Reference no. 36029414.7.0000.5440). Because of the retrospective nature of the study, the requirement for written informed consent was waived.We selected 137 consecutive MR arthrography examinations of the shoulder performed at the university hospital or at a private diagnostic imaging clinic between 2011 and 2013. We applied the following exclusion criteria for MR arthrography examinations of the shoulder: failure to follow the standard protocol ; unsatisfactory image quality because of motion or magnetic susceptibility artifacts; poor distension of the joint capsule by the contrast medium; postoperative acquisition; and extensive lesion of the anterior labrum.On the basis of the study criteria, 44 examinations were excluded. Therefore, the final sample comprised 93 MR arthrography examinations of the shoulder. Of the 93 corresponding patients, 70 (75.3%) were male, with a mean age of 28 ± 9.3 years , and 23 (24.7%) were female, with a mean age of 32 ± 13.2 years . There were 70 patients with a history of traumatic instability, the remaining 23 patients having nothing in their clinical history, medical record, or pre-examination interview that could lead to a suspicion of instability.The MR arthrography examinations involved the acquisition of at least one volumetric sequence in the axial plane , which w- A 1.5-T Philips Achieva , with a SENSE-Shoulder-4 or SENSE-Flex-M coil and acquisition of at least one of the following sequences: three-dimensional (3D) T1-weighted; 3D T1-weighted; 3D T1-weighted VISTA; or proton density- weighted VISTA ISO- A 1.5-T Signa HDxt , with a SHLDRPA4 coil and acquisition of a 3D FIESTA sequence- A 3.0-T Discovery MR750 , with an HD Shoulder coil and acquisition of a 3D FIESTA sequenceThe images were archived and anonymized, after which they were interpreted by two radiologists, a fellow in musculoskeletal radiology (reader 1) and a senior musculoskeletal radiologist at our institution with four years of experience (reader 2). The two readers, who were working independently, were blinded to the clinical history, signs/symptoms, surgical findings, examination reports, and clinical evolution of the patients. For the assessment of intraobserver agreement, one of the observers (reader 1) re-evaluated the findings six months after the first reading.We conducted a retrospective analysis of the cases in order to characterize the following: the glenoid attachment pattern of the anterior band of the IGHL (AB-IGHL), distinguishing between type I, in which the AB-IGHL has a predominantly chondrolabral origin , and typ, version 9.0 . We used the chi-square test to determine whether the types of attachment were associated with the presence or absence of glenohumeral dislocation/instability and labral injury. We used the kappa statistic with a 95% confidence interval (95% CI) for the evaluation of interobserver and intraobserver agreement rates, whereas we used the weighted kappa statistic for the evaluation of the AB-IGHL attachment level. The interpretation of the agreement analysis results was based on the following criteria,26: no agreement (κ < 0); poor agreement (κ of 0-0.19); fair agreement (κ of 0.20-0.39); moderate agreement (κ of 0.40-0.59); substantial agreement (κ of 0.60-0.79); and almost perfect agreement (κ of 0.80-1.00).The statistical analysis was performed with the Statistical Analysis SystemThe AB-IGHL emerged from the chondrolabral rim (type I pattern) in 50 cases (53.8%) and directly from the glenoid rim (type II pattern) in 43 cases (46.2%). The evaluation of the attachment pattern achieved near-perfect interobserver agreement  and intraobserver agreement .p = 0.20).After the cases in which the physician request or the patient interview indicated suspicion or complaint of dislocation, instability, or labral injury had been excluded, the sample comprised 23 patients without a clinical history of instability. Of those 23 patients, 15 (65%) had a type I attachment pattern and 8 (35%) had a type II attachment pattern. We found no significant association between the type of attachment pattern and the presence or absence of glenohumeral dislocation/instability and labral injury (The AB-IGHL attached to the glenoid rim at the 4 o’clock position in 58 cases (62.4%), at the 3 o’clock position in 14 (15%), and at the 5 o’clock position in 21 (22.6%). In the assessment of the ligament attachment position, there was substantial interobserver agreement  and intraobserver agreement .-31. The anatomy of the glenohumeral ligaments is complex and variable, various patterns having been described in the literature, which makes it difficult to gain a proper understanding of it. Although the IGHL is probably the most widely studied of those ligaments, there is as yet no consensus about its level of origin, size, and most common attachment pattern.Several recent studies conducted in Brazil have highlighted the importance of using imaging methods for evaluating the musculoskeletal system,19,33, descriptions of those aspects on MRI or MR arthrography examinations are less common. In our study, the use of MR arthrography enabled us to analyze a sample larger than those of previous anatomical studies. We were able to identify the IGHL in all 93 of the examinations analyzed, which confirms that MR arthrography is an excellent method for assessing this ligament and that it can be used in routine practice. In addition, the characterization of the anatomy of the AB-IGHL glenoid attachment by a radiologist with experience in the method proved to be reproducible and reliable. Although reports in the literature state that diagnosing isolated lesions of the IGHL glenoid attachment (known as ALIPSA/GAGL lesions) with MR arthrography is a challenge and that arthroscopy is the method of choice in those cases, we believe that a better understanding of the IGHL variations and their depiction on MR arthrography can contribute to changing that idea.The results of the present study confirm those of previous studies showing anatomical variations in the attachment of the AB-IGHL. More than 46% of the cases in our sample had an IGHL attached to the glenoid rim, medial to the fibrocartilage of the glenoid labrum. For the identification of that anatomical variation, the interobserver and intraobserver agreement were almost perfect. Although there are anatomical studies in the literature focusing on the assessment of the different glenoid attachment patterns,19. In the present study, a predominance of the type I pattern was observed, although the prevalence of the type II pattern, in which the AB-IGHL attaches mainly to the glenoid rim and neck, was also found to be high. A possible reason for that is a selection bias-many patients selected for inclusion in the present study had undergone MR arthrography because of complaints of traumatic shoulder instability, resulting in a specific population that differs from that of asymptomatic people. In an attempt to obtain an unbiased sample, cases in which there was suspicion or a complaint of glenohumeral instability and cases of shoulder dislocation were excluded, after which a new analysis was carried out. In that second analysis, the distribution of the two types was more similar to that reported in previous anatomical studies: type I and type II attachment patterns were observed in 65.2% and 34.8% of the cases, respectively. However, there was no association between the type of glenoid attachment and the presence or absence of glenohumeral instability/dislocation and labral injury.Anatomical studies of the variations of the AB-IGHL attachment to the glenoid rim show a predominance of the type I pattern, in which most fibers originate from the chondrolabral rim and some extend to the glenoid rim, with incidence rates of 80-88%, over the type II pattern, in which they originate directly from the bone margin,3,6,7. Because their findings on imaging examinations are similar, ALIPSA/GAGL lesions can mimic a type II attachment pattern. However, ALIPSA/GAGL lesions are considered quite uncommon, accounting for less than 3% of the labral-ligamentous lesions in patients with a history of shoulder instability. Although it is difficult to distinguish between these two conditions on MR arthrography, the presence of a fibrocartilaginous labrum well adhered to the glenoid rim clearly distinguishes a Bankart or Perthes lesion from an ALIPSA/GAGL lesion or a type II attachment of the IGHL to the glenoid rim. The results of this study, in which we found an IGHL glenoid attachment position between 3 o’clock and 5 o’clock, are in agreement with those of anatomical studies of frozen cadavers, which found attachment positions starting at 3 o’clock, with decreasing thickness toward the lower part of the glenoid, as well as between 2 o’clock and 5 o’clock, the extent of the attachment being greatest at the 4 o’clock position.Because we did not make any arthroscopic correlation, we cannot rule out completely the possibility that some of the patients in our sample had an ALIPSA/GAGL lesion, in which there is avulsion of the IGHL attachment from the glenoid without damage to the anteroinferior labrum, identifying these anatomical variations around the anterior glenoid rim on MR arthrography is important for the correct interpretation of the imaging findings.Our study has some limitations. First, because it was a retrospective study, the clinical data used were based on the summarized information available on physician requests, electronic medical records, and pre-examination interviews. In addition, there was no standardization of the volume injected into the joint or of the examination protocol. However, a prospective study involving an invasive procedure could raise ethical questions. In addition, although the observers were blinded to the clinical history of patients, findings such as Hill-Sachs and Bankart lesions often made it obvious which cases had a history of traumatic instability. Another limitation is the fact that there is no method of reference or gold standard to confirm the findings of the MR arthrography examinations, which indicates the need for further studies in that area. Furthermore, there could have been a selection bias, given that most of the patients in our sample had a clinical history of shoulder instability, which could affect the usual anatomical aspect of the IGHL-labrum complex. To minimize that limitation, we performed a second analysis, in which cases with a history or signs of instability were excluded. However, as previously mentioned, that analysis was based only on the data available on the physician request and not on a detailed clinical evaluation of the patients. Despite the abovementioned limitations, there are reasons to believe that the results of our study are useful, because they are in agreement with the attachment patterns and levels found in previous anatomical studies, as well as being consistent and having almost perfect interobserver and intraobserver agreement. As in the assessment of other joints, such as the knee menisciThe treatment of traumatic shoulder instability is often surgical and depends on an accurate preoperative diagnosis and careful planning for each type and degree of injury. Therefore, we can conclude that MR arthrography provides an effective assessment of the anatomy as well as of the different patterns and positions of the AB-IGHL glenoid attachment and that radiologist knowledge about them can contribute to a better understanding of the anatomical variations and of less common lesions of the IGHL-labrum complex associated with anterior shoulder instability, which help achieve correct diagnoses and more appropriate treatment planning.


With the increase in pitch, the maximum temperature of SDTSV increases very slowly when β = 0An accurate equivalent thermal model is proposed to calculate the equivalent thermal conductivity (ETC) of shield differential through-silicon via (SDTSV). The mathematical expressions of ETC in both horizontal and vertical directions are deduced by considering the anisotropy of SDTSV. The accuracy of the proposed model is verified by the finite element method (FEM), and the average errors of temperature along the X-axis, Y-axis, diagonal line, and vertical directions are 1.37%, 3.42%, 1.76%, and 0.40%, respectively. Compared with COMSOL, the proposed model greatly improves the computational efficiency. Moreover, the effects of different parameters on the thermal distribution of SDTSV are also investigated. The thermal conductivity is decreased with the increase in thickness of SiO Through-silicon via (TSV) is a key structure of 3D integrated circuits (IC) ,2,3,4,5.2, and the radius of TSV, have been considered, and the accuracy of the proposed model has been verified by FEM. Hu et al. [In the last decade, the thermal models of TSV, coaxial TSV, and TSV arrays have been systematically investigated and established ,16. Meanu et al.  proposedu et al.  developeu et al.  proposedu et al.  proposedu et al.  also invu et al.  proposedu et al.  establisu et al.  establisu et al.  proposedu et al.  proposedu et al.  proposedIn recent years, SDTSV and derivative structures have been investigated by several researchers ,31,32. LIn this paper, an accurate and fast ETC model is established for SDTSV. The mathematical equations for the ETC of SDTSV are deduced in The particular structure of SDTSV is shown in 2), and silicon (Si) can be assumed as the parallel relationship, and the thermal resistance When the heat flow Q in any direction is applied to SDTSV, it is divided into vertical and horizontal components, and the ETC model in the vertical direction is deduced first. In this model, the heat flow along the copper (Cu), silicon dioxide , 5, the thermal conductivity of SDTSV in the horizontal direction can be divided into two cases, as shown in The horizontal section of SDTSV is shown in The materials in q1 and q7 are Si, and the thermal resistances in q1 and q7 can be calculated by Equation (5). Meanwhile, the thermal resistance in q2 and q6 can be obtained by Equation (6), and the thermal resistance in q3 and q5 can be obtained by Equation (7). The thermal conductivity in q4 can be obtained by Equation (8). Accordingly, the ETC of SDTSV can be calculated by Equation (4) when In the Similarly, the ETC in case 2 Equations (11)–(17) show that The accuracy of the ETC model established in the previous section is verified by FEM, and the effects of the parameters on the thermal distribution are investigated. In addition, the error of the proposed model is analyzed.2 is set to 0.2 μm, the rotation angles 2) is imposed on the left [The accuracy of the proposed ETC model is verified by COMSOL. In this study, the numerical solutions of Equations (1)–(17) are solved by MATLAB, and the results are compared with those obtained by COMSOL. The parameters of FEM are shown in the left ,34. The the left ,35,36,37The comparison between the proposed model and COMSOL is shown in 2 has a poorer heat-transfer performance than Cu and Si, which results in the detour of the isotherm. However, the SDTSV is treated as a lump model in the proposed model, which ignores the inside features, so the isotherm is smooth.The 3D temperature distributions of SDTSV obtained by the proposed model and COMSOL are shown in 2) on the thermal conductivity of SDTSV are investigated. In particular, the thickness of SiO2 is set from 0.1 μm to 0.6 μm, with a step size of 0.1 μm, and the pitch between the TSVs in SDTSV changes from 25 μm to 90 μm, with a step size of 5 μm. The ETCs of SDTSV in horizontal and vertical directions obtained by COMSOL are calculated byThe accuracy of the proposed model is verified above. Based on the proposed model, the effects of different parameters  is imposed on the left. The opposite side of the heat surface is set to 20 °C, and the other surfaces have no heat exchange with the outside. The simulation results of the temperature distribution by FEM are shown in The thermal distributions of SDTSV array in x and y directions are further investigated in this section. A Based on the comparisons, the accuracy of the proposed model is verified by COMSOL. The maximum temperature error is lower than 1.5165 K, which is relatively small. In addition, compared with FEM, the calculation time of the proposed model is reduced from approximately 300 s to 1.9 s. However, the error of equivalent model is inevitable, which is its limitation. Compared with the finite element method (FEM), the equivalent model greatly improves the computational efficiency at the expense of certain accuracy. In the published studies, the maximum error of thermal conductivity in  is approAccording to the results obtained by COMSOL, the ETC in a vertical direction is larger than in a horizontal direction. This is because the Cu runs through the SDTSV along the vertical direction, and it is treated as the main channel of thermal dissipation. When β is equal to 0In this paper, an accurate equivalent thermal model is proposed to describe the thermal distribution of SDTSV, and the main conclusions can be summarized as follows:(1)An accurate equivalent thermal model is established for SDTSV, which can describe the thermal distribution of SDTSV along an arbitrary angle. The mathematical expressions of ETC in horizontal and vertical directions are deduced;(2)The accuracy of the proposed model is verified by COMSOL, and the average errors of temperature at (3)2 increases.The effects of different parameters on the thermal distribution of SDTSV are investigated based on the proposed model. As the pitch increases, the maximum temperature of SDTSV increases very slowly when β = 0


Investigation on the long-term thermal response of precast high-strength concrete (PHC) energy pile is relatively rare. This paper combines field experiments and numerical simulations to investigate the long-term thermal properties of a PHC energy pile in a layered foundation. The major findings obtained from the experimental and numerical studies are as follows: First, the thermophysical ground properties gradually produce an influence on the long-term temperature variation. For the soil layers with relatively higher thermal conductivity, the ground temperature near to the energy pile presents a slowly increasing trend, and the ground temperature response at a longer distance from the center of the PHC pile appears to be delayed. Second, the short- and long-term thermal performance of the PHC energy pile can be enhanced by increasing the thermal conductivity of backfill soil. When the thermal conductivities of backfill soil in the PHC pile increase from 1 to 4 W/(m K), the heat exchange amounts of energy pile can be enhanced by approximately 30%, 79%, 105%, and 122% at 1 day and 20%, 47%, 59%, and 66% at 90 days compared with the backfill water used in the site. However, the influence of specific heat capacity of the backfill soil in the PHC pile on the short-term or long-term thermal response can be ignored. Furthermore, the variation of the initial ground temperature is also an important factor to affect the short-and-long-term heat transfer capacity and ground temperature variation. Finally, the thermal conductivity of the ground has a significant effect on the long-term thermal response compared with the short-term condition, and the heat exchange rates rise by about 5% and 9% at 1 day and 21% and 37% at 90 days as the thermal conductivities of the ground increase by 0.5 and 1 W/(m K), respectively. With the development of energy geotechnical engineering, numerous studies are being performed worldwide to apply the ground source heat pump (GSHP) technology in the construction of diaphragm walls, foundations, tunnels, and other ground-embedded structures ,3,4,5,6.The advantages with respect to the thermal response, thermal properties, and the thermo-mechanical performance of energy piles have been discussed in previous studies ,18,19,20To date, the previous investigations of energy piles concentrated on the cast-in-place pile, CFG pile, and steel pile ,22,26,31In the current study, in situ experiments of energy piles were performed at Southeast University to evaluate the variation of the long-term thermal behavior of the PHC energy pile. Furthermore, a 3D numerical model was developed to simulate the thermal response of PHC energy pile in layered foundation. Finally, based on the method of numerical simulation, the influences of different parameters on the long-term thermal response of PHC pile in layered foundation were analyzed and discussed. The relevant results can provide guidance for the design and construction of PHC energy piles in layered foundation, especially when the long-term thermal behavior needs to be considered.The testing site of the PHC energy pile is located at Jiulonghu Campus, Southeast University, Nanjing, China. The geographic coordinates of the experimental site are 31°53′ N latitude and 118°49′ E longitude. The description of the experimental location of the field thermal response tests (TRTs) is displayed in The experimental site is located on the Qinhuai River floodplain geomorphic unit with plane terrain. The groundwater table is approximately 1.0 m in depth. The soil mass stratification characteristics were obtained by performing the piezocone penetration (CPTU) test and borehole sampling analysis. The first soil layer is plain fill, and the second layer is a recent sedimentary soil, which is divided into five sublayers. Undisturbed soil samples were taken from each soil layer, and their physical and mechanical properties were assessed in the laboratory. The plastic limit, liquid limit, plasticity index, void ratio, water content, and unit weight of each soil layer are presented in The DZDR-S device based on transient plane heat source method was adopted in the current study to measure the thermophysical properties of each stratified soil . The detThe energy pile in the test site was a pretensioned spun concrete pile, and the field manufacture and installation processes of the PHC energy pile are shown in The U-type ground heat exchanger used in the field tests was a high density polyethylene (HDPE) pipe, and the buried depth of the vertical ground heat exchanger reached 24 m. The external diameter, inner diameter, and wall thickness of the vertical ground heat exchanger were 25, 20.4, and 2.3 mm, respectively. Water was chosen as the circulating fluid in the heat exchange pipe. The 260-mm-length stainless steel supports were set every 3 m along the depth of the pile to keep the same distance between the two pipes.The TRT system was employed in field experiments. The layout of sensors in the ground temperature boreholes is shown in 3/h during the first 481 h, and the flow rate of circulating water was set as 0.85 m3/h with the operation time from 482 to 1266.66 h. The inlet water temperature, outlet water temperature, ambient air temperature, and flow rate of circulating water of the field test are presented in The field test started from 22 November 2018 to 14 January 2019. The flow rate of circulating water in the system was set as 0.7 mA sensitivity analysis was performed to assess the uncertainty of the experimental data. The uncertainties of measured and calculated parameters were evaluated.iX is iδX, the relative uncertainty When F of the test is a function of a set of independent measured parameters, and the relative uncertainty F can be obtained by the root-sum-square method [The result e method :(2)δRF=δThe relative uncertainties of the inlet and outlet temperature, flow rate, and ground temperature are 0.20%, 0.30%, and 0.48%. The relative uncertainty of the calculated parameter (heat exchange rate) is 2.28%.The ground temperature distribution characteristic in the boreholes with the distance of 0.5 m from the center point of the energy pile at the beginning of the field experiments is shown in 2/s, which are approximately 1.5 and 1.2 times than that of 6.1 m depth soil layer. The soil layers at the depths of 13.7 and 17 m have a favorable heat dissipation capability, and the heat in soils close to the energy pile tends to diffuse into the soils farther away. Accordingly, the growth rate of ground temperature close to the pile in the soil layer with higher thermal conductivity and thermal diffusivity is relatively low.The variations of ground temperature increments at different running times and depths in BH1 are shown in Some temperature sensors in the boreholes were damaged due to their long-term service and because of installation problems, which resulted in missing some of the field experimental data. The ground temperature variations in the BH1, BH2, and BH3 at the depths of 13.7 and 17 m can be obtained from the test site, which is shown in As the field experimental conditions are relatively limited, some factors affecting the long-term thermal performance of PHC energy pile and ground temperature variation cannot be changed directly. Therefore, the numerical simulation was applied in the current study to make up for the limitation of the field experiment. A parametric analysis based on numerical simulations was conducted to provide a reference for further investigation of the thermal behavior of PHC energy pile and reasonably design the PHC energy pile.In the current study, some assumptions were described to simplify the conjugate heat transfer mechanisms of heating operation of PHC energy pile in the layered foundation. First, the heat transfer of the numerical model caused by the groundwater flow is not considered according to the soil properties and actual geological conditions at the test site . Second,3), According to the aforementioned assumptions, the heat conduction mechanism of PHC energy pile and soil in the model can be described by the following equation:3), p,fC is the specific heat capacity at a constant pressure of the fluid (J/(kg K)), 3).In consideration of the liquid flow condition, the continuity, momentum, and energy conservation equations of water inside the energy pile can be represented by Equations (4)–(6).The continuity, momentum, and energy conservation equations of incompressible fluid inside the pipe are expressed in Equations (7)–(9).The heat exchange through the pipe wall (2 K)), The effective heat transfer coefficient .The upper boundary (convective heat transfer boundary) condition of the model can be expressed from Equation (14).2 K)), and The lateral boundary and bottom boundary  conditions of the model can be expressed from Equation (15).Moreover, the initial hydraulic conditions of the water inside the energy pile can be described as follows:The hydraulic boundary conditions of the water inside the energy pile can be presented as follows:The inlet fluid temperature, outlet fluid temperature, and flow rate of field TRTs were applied in the numerical model. The hydraulic boundary inside the PHC pile had no slip. The geometric dimensioning and mesh configuration of the soil and the PHC energy pile are presented in The field experimental data can be used to verify the accuracy and reliability of the established numerical model. The ground temperatures in BH1 under the numerical simulation of 180 h are compared with the field test results to validate the numerical model.The comparison between field test data and numerical simulation results is presented in 3/h. The various influencing factors of the thermal response experiments considered in the numerical analysis are listed in q) of the PHC energy pile can be defined as:m is the mass flow rate of the circulating fluid (kg/s), inT is the inlet temperature of the fluid (K), outT is the outlet temperature of the fluid (K), and l is the length of the energy pile (m).Based on the aforementioned numerical model, further studies and analyses concerning the long-term thermal response of PHC energy pile under different conditions are presented below. The thermophysical properties of backfill soil in PHC pile, initial ground temperature, and ground properties are very important factors for the design and operation of PHC energy piles. In the parametric research, the inlet fluid temperature and flow rate are set as the constant values of 40 °C and 0.5 mIn the parametric study, the numerical simulation of the backfill soil in PHC pile and pile follows the heat conduction of solid, and the heat transfer mechanism is similar to the heat conduction mechanism of the PHC pile and ground.The influence of thermal conductivity of backfill soil in PHC pile on the heat exchange rate of energy pile is shown in As seen in The influence of the initial ground temperature on the temperature variation is shown in Based on the field experimental data, as shown in The thermophysical properties of the ground have an effect on the ground temperature variation at the relatively long-term operation. The relatively higher thermal conductivity of the soil layers can generate a slower growth trend of the ground temperature near to the PHC energy pile. The influence of the soil to the energy pile temperature weakens as the radial distance from the pile increases.Based on the theoretical analysis of heat transfer, the 3D numerical simulations of PHC energy pile in the layered foundation were performed. The numerical data agreed very well with the measured in situ data.The parametric analysis shows that the thermal conductivity of the backfill soil in PHC pile, initial ground temperature, and thermal conductivity of the ground both have an influence on the long-term thermal performance and ground temperature variation, while the impact of the specific heat capacity of the backfill soil is negligible.The short- and long-term heat transfer performance of the PHC energy pile can be enhanced by increasing the thermal conductivity of the backfill soil in the PHC pile. The heat exchange rates reach 29.87, 41.15, 47.16, and 51.05 W/m at 1 day and 18.30, 22.34, 24.20, and 25.31 W/m at 90 days as the thermal conductivities of the backfill soil are 1, 2, 3, and 4 W/(m K), which have been improved by about 30%, 79%, 105%, and 122% at 1 day and 20%, 47%, 59%, and 66% at 90 days compared with the PHC pile backfill with water.The initial ground temperature variation also has an impact on the short- and long-term thermal response. The heat exchange rates of the energy pile, respectively, increase by about 13% and 11% at 1 day and 90 days as the initial ground temperature reduces 3 °C, and they decrease by 13% and 11% at 1 day and 90 days as the initial ground temperature rises 3 °C.The thermal conductivity of the ground produces a significant effect on the long-term heat exchange amount of energy pile, while it has a relatively small impact on the short-term performance. When the thermal conductivities of each soil layer rise by 0.5 and 1 W/(m K), the heat exchange rates have improved by about 5% and 9% at 1 day, and they have improved by 21% and 37% at 90 days.The research concerning the long-term thermal response of a PHC energy pile in a layered foundation is performed by employing field experiments and numerical simulations. The main conclusions are summarized as follows:In future studies on the thermal performance of PHC energy pile, the influences of groundwater seepage and operation mode need to be explored. Moreover, the various backfill materials inside the PHC pile  may generate an impact on its thermal behavior and ground temperature variation, which can also be considered in future studies.


The effects of lithium niobate (LiNbO3), an interdigital transducer (IDT), and SiO2 thin films on the evolution of the phase velocity, electromechanical coupling coefficient (k2), and temperature coefficient of frequency were studied by employing a finite element method simulation. Furthermore, a longitudinal coupling resonator filter was designed. To investigate the SAW characteristics of the filter, a transient analysis was conducted to calculate the electrical potential and particle displacement under the resonance condition and to analyze the frequency response. The study concluded that this new multilayer structure can be applied to design and manufacture a variety of high-frequency and wideband SAW filters with a temperature compensation function, for operation above the GHz range.Surface acoustic wave (SAW) devices are widely used in many fields such as mobile communication, phased array radar, and wireless passive sensor systems. With the upgrade of mobile networks, the requirements for the performance of SAW devices have also increased, and high-frequency wideband SAW devices have become an important research topic in communication systems and other application fields. In this paper, a theoretical study for the realization of a layered SAW filter based on a new SiO However, the new multilayer structure can solve this problem as the complementary advantages between materials can be utilized by selecting a multilayer medium comprising different materials. For example, the surface source or interface source structure created by the deposition of a piezoelectric film on some high-speed materials can improve the velocity of the SAW and the electromechanical coupling coefficient simultaneously. The multilayer structure has the advantages of not only high sound speed, large electromechanical coupling coefficient, and better frequency and temperature stability but also process simplicity and economic cost savings, which reduces the requirements of photolithography technology in the production of high-frequency devices.Surface acoustic wave (SAW) devices are widely used in mobile communication, industrial control, and environmental and biological sensors because of their good consistency, small size, strong anti-interference ability, and low cost. With the progression of high-frequency and broadband communication, the development of high-frequency devices such as SAW devices and film bulk acoustic resonators used in the GHz range has become an emerging research hotspot . For therequired : (1) redBecause of the unique advantages of multilayer structures, many scholars have conducted extensive and in-depth research on multilayer structures in recent years. S. Maouhoub  investigE = 1200 GPa), a high longitudinal wave sound velocity (18 km/s), and a low material density (ρ = 3.51 g/cm3), it can be combined with a piezoelectric film to prepare high-frequency SAW devices with unique advantages. Further, because of its excellent thermal conductivity, the diamond SAW device has the ability to communicate with super-high power, even at high frequencies, and its performance can exceed that of traditional SAW devices. However, because of the lack of piezoelectric properties, it is necessary to add piezoelectric thin-film layers. LiNbO3 crystals are multifunctional materials with favorable piezoelectric, nonlinear optical and electro-optic properties and can complement the advantages of diamond substrates to produce SAW devices with a layered structure. Although LiNbO3 exhibits the highest piezoelectricity among piezoelectric materials, it has poor temperature stability. Meanwhile, SiO2 has excellent temperature stability; the authors have designed a new SAW substrate with a large coupling factor and excellent temperature stability by combining LiNbO3 and SiO2 films. Moreover, there are multiple modes of SAWs in multilayered structures. High-order SAWs or bulk acoustic waves with faster propagation speeds can also be used in the design, and the best mode of surface waves can be selected for different design requirements.Because the diamond has an extremely high elastic modulus  element structures were obtained by changing the thickness of each film layer, and the propagation characteristics of Rayleigh and Sezawa waves were accurately analyzed. The propagation state of the acoustic signal in the 2D complete structure was obtained via time-domain analysis. The results show that the structure can have good application prospects in the design of high-frequency and wideband SAW devices (such as filters and duplexers) with temperature compensation functions in the future.In this study, to solve the problems of low working frequency, narrow bandwidth, and poor temperature stability of traditional single-crystal structure SAW devices, a new longitudinally coupled SAW resonator filter (LCRF) with SiOT), strain (S), electric field (E), and electric displacement (D) in a stress-charge of a piezoelectric crystal. This coupling is governed by the piezoelectric constructive equations [2). The basic wave equation in the piezoelectric substrate can be derived mathematically from Newton’s equation and Maxwell’s equation, which couple the electric potential and displacement components together [Piezoelectric effect is a phenomenon of mutual conversion between mechanical energy and electrical energy, which involves the interaction between electrical quantity and mechanical quantity. In this paper, COMSOL Multiphysics 5.6 is used to simulate and analyze the structure. In COMSOL, the coupling between structure domain and electrical domain can be expressed as the relationship between material stress and dielectric constant under constant stress, or the coupling between material strain and dielectric constant under constant strain . Finite quations  given bytogether :(3)cijkl2 thin film can be used as temperature compensation layer to achieve high temperature stability of SAW filter. 2/IDT/LiNbO3/diamond/Si structure considered in the modeling, and the structure of the LCRF in this design is shown in SiOFEM simulation is an essential step in the design and fabrication of SAW devices. The device simulation can not only improve design accuracy, but it can also reduce unnecessary material losses. In this article, the software used for FEM analysis is COMSOL Multiphysics 5.6, which can easily perform piezoelectric coupling analysis and is used to analyze the response of 2D or 3D structural devices to changes in voltage and mechanical load. Thus, this software is suitable for the analysis and simulation of SAW devices. The simulation results can be used as the reference for the design and optimization of future SAW devices . Becausep is the distance between two adjacent metal electrodes; a is the width of the metal electrode; and 2 layers, respectively. To eliminate the influence of the metallization rate and obtain the maximum reflectivity of the reflector, the metallization rate (MR = a/p) was designed to be 0.5. After the metallization rate was determined, because the propagation characteristics of the layered SAW structure are independent of the wavelength, the SAW wavelength was designed to be λ = 6 μm. Because most of the energy of the SAW is confined to the surface, and the thicknesses 3 surface. Silicon is assumed to be a semi-infinite substrate. The film thickness ratios GN, INN, and OUTN indicate the number of reflective gratings, input fork index, and output fork index, respectively. The specific geometric parameters involved are shown in In sy media ; therefoThe materials used in the finite element simulation included aluminum, lithium niobate, diamond, silicon dioxide, and silicon. The main characteristic parameters of materials ,18,19,20In order to make the simulation results more accurate and reduce the amount of simulation calculations, the modal analysis of the layered LCRF is generally performed using a pair of interdigitated electrodes with periodic boundary conditions. The detailed electrical and mechanical boundary conditions of the numerical model are listed in 2/IDT/LiNbO3/diamond/Si layered unit structure was carried out with COMSOL Multiphysics software, and the COMSOL Multiphysics model used in this work was built in 2D Structural Mechanics Module, with emphasis on the analysis of its resonance mode and frequency response. Through the modal analysis, symmetrical modes and antisymmetric modes can be obtained, and the occurrence of their resonant frequency The finite element analysis of the SiOlectrode . Plots olectrode . The resp can be obtained as follows [According to the working principle of the SAW filter, the SAW excited by the IDT can be regarded as the superposition of multiple pairs of IDT excitation signals. When the finger distance p is an integer multiple of the SAW half-wavelength λ/2, the IDT can superimpose the largest excitation signal. Therefore, the relationship between the intrinsic frequency of the SAW and  follows :(5)f0=vpThe electromechanical coupling coefficient  formula :(7)k2=π2TCF is obtained by substituting the phase velocity calculated at temperature T and T0 = 25 °C for The 3 piezoelectric film, multiple modes such as Rayleigh, Sezawa, and high-order Sezawa modes coexist in the same layered structure. First, we built the LiNbO3/diamond/Si model to precisely determine the acoustic wave propagation properties on this layered structure. The Rayleigh and Sezawa anti-symmetric resonant modes of the X-displacement component of the 2D unit structure when the piezoelectric film thickness ratio , the magnitude of the particle displacement decreased. The Rayleigh vibration mode had a larger amplitude than the Sezawa mode, and the amplitude declined with a depth quicker than that observed in the Sezawa mode because the Rayleigh wave energy is mainly concentrated on the surface, whereas the Sezawa wave energy is distributed in the base. In addition, as the thickness of the piezoelectric layer increased, the SAWs were increasingly confined near the surface.Because the acoustic velocity of the diamond substrate is higher than that of the LiNbO3/diamond/Si structure and then investigated the influence of thickness variation of the piezoelectric layer and thermal compensating layer on the key performance parameters of the LCRF in the SiO2/IDT/LiNbO3/diamond/Si structure.The performance of a SAW device with a multilayer film structure is not only affected by the electrode structure of the transducer and the characteristics of the piezoelectric material, but also related to the thickness of the piezoelectric film and the thickness of the interdigital electrode. In the layered structure, the SAW is a dispersive wave, and the acoustic parameters are dispersive, as determined by the thickness ratio of the piezoelectric and other films to the wavelength of the acoustic wave. Therefore, setting appropriate geometric parameters can significantly improve the performance of SAW devices. To obtain the best performance structure, a detailed simulation analysis was performed on the thickness of the interdigital electrode, piezoelectric layer, and temperature compensation layer. First, we studied the effects of the metal electrode and piezoelectric film on the propagation characteristics of SAWs in the IDT/LiNbOThe mass loading effect of the metal electrode will be introduced when the surface of piezoelectric medium is covered with metal film . To studAs shown in 3 layer thickness, the phase velocities of the Rayleigh mode and Sezawa mode drop with increasing electrode thickness, while For a unit model with fixed 1.5 μm LiNbOAs shown in When the electrode thickness is zero or very small, the resonant and anti-resonant frequencies are basically the same, but with an increase in the electrode thickness, the Rayleigh wave acoustic field begins to move to the surface of the piezoelectric layer; the resonant and anti-resonant frequencies become significantly different and, according to Formula (7), correlate with the corresponding 2/IDT/LiNbO3/diamond/Si structure, we first used the IDT/LiNbO3/diamond/Si structure. In the next stage of the study, a thin film of SiO2 was coated over the surface of the LiNbO3 film, and the resonance frequencies of both modes with different thicknesses of the LiNbO3 film were recorded. The other structural parameters are listed in The characteristics of SAWs in piezoelectric multilayer media are not only affected by the characteristics of the piezoelectric layer material but also depend on the thickness of the piezoelectric layer. Initially, to validate our simulation method for the SiO3/diamond/Si structure are presented in 3 film thickness, whereas that of the Sezawa mode decreases more dramatically. As displayed in The simulation results for the propagation characteristics of the IDT/LiNbO3 and SiO2 layers are very thin, and these values decrease to reach those of the piezoelectric film. In the Sezawa mode, a high 3 thickness dependence of 2. In contrast, the Sezawa mode –(4) differ, where 2/IDT/LiNbO3/diamond/Si versus the normalized thickness of the SiO2 layer with different thicknesses of the LiNbO3 layer. For 2 layer thickness. In the case of 3 single crystal reaches −75 ppm/°C, and it is apparent that the existence of the SiO2 film caused an improvement in the TCF. Usually, as shown in 2 overcoat is preferred.The change in material parameters leads to a change in the SAW velocity, and the TCF is obtained using Equation (8). Therefore, the multilayer structure with added high-speed substrate can greatly increase not only the propagation velocity of SAWs but also the electromechanical coupling coefficient. A faster propagation velocity and larger To simulate the real operation conditions of the SAW filter, the structure was analyzed in the time domain. Moreover, to reduce computational time, we modeled the SAW filter as a 2D system. In this model, t = 3 ns, the SAWs reach the output electrode.The transient simulation was run for 50 ns with the timestep of 0.1 ns. 21 characteristics in the frequency domain analysis of the filter designed with the SiO2/IDT/LiNbO3/diamond/Si structure. It can be seen that the transmission characteristics of the device are the best at the center frequency 2/IDT/LiNbO3/diamond/Si compared with other SAW material systems are listed in SAW parameters of SiO2/LiNbO3/diamond/Si is found to have a zero-temperature coefficient, and thus this material can be regarded as an ideal system for high-frequency wide-bandwidth applications. It is worth noting that in most of the literature, the width of the interdigital electrode reaches the submicron level; we set λ as 6 μm, and hence, the difficulty of manufacturing is reduced. If we continue to reduce its width, the operating frequency (f0) will double. For example, when λ = 1 μm, f0 exceeds 10 GHz in the Sezawa mode.In contrast, SiO2/IDT/LiNbO3/diamond/Si composite substrate structure designed to realize high-performance SAW devices was investigated. The effects of the thicknesses of IDT, LiNbO3, and SiO2 thin films on the structural performance were numerically evaluated using a 2D finite element model. In addition, the phase velocities, coupling coefficients, and temperature coefficients of the Rayleigh and Sezawa waves were calculated.In this study, a new SiO3 single crystals, the phase velocity and electromechanical coupling coefficient of the layered structure increased by 144% and 17.7%, respectively. Furthermore, the layered structure has high temperature stability. From the results, we can conclude that the structure is promising for the realization of high-performance SAW filters at frequencies above the GHz range as long as the width of the interdigital electrode can be set reasonably. In the same way, the results provided in this study are of great importance for the future design of high-performance SAW devices on SiO2/IDT/LiNbO3/diamond/Si layered structures.As a result, the layered structure was found to have a high phase velocity of up to 10 km/s and a high electromechanical coupling coefficient of 6.47% with a small temperature coefficient as low as 0 ppm/°C. Compared with those of traditional LiNbO