Studies show that each kind of fiber has its own advantages in improving the properties of asphalt binders. However, there are very limited research studies about mixed fiber-reinforced asphalt (MFRA). In this study, two kinds of fibers, basalt fiber (BF) and lignin fiber (LF), were selected to reinforce SBS (styrene–butadiene–styrene triblock copolymer)-modified asphalt, which is now widely used in pavement engineering. MFRA samples with different fiber mix ratios (FMRs) were prepared for the tests of softening point, ductility, and rheological properties, the micromorphology of which was studied by using scanning electron microscope (SEM). The oil  absorption rates of mixed fibers with different FMRs were also tested. The results show that the properties of MFRA were affected by the physical and chemical properties of fibers. Basalt fiber can better strengthen the physical properties of MFRA, while lignin fiber is good for improving the rheological properties, and the oil absorption rate of lignin fiber is higher than that of basalt fiber. Furthermore, the best FMR calculated by the efficacy coefficient method (ECM) was recommended as 1:2 (BF:LF). An interface layer between the fiber and asphalt was observed from the micro images, proving that the fibers bond well with the asphalt. Generally, mixing BF and LF together into SBS-modified asphalt could make full use of the advantages of different fibers and reinforce the comprehensive performance of MFRA better.  With the rapid development of the modern economy, more and more fibers are being used in scientific research and engineering practice. Using fibers as reinforcements can often have better economic and performance advantages in extending the service life of matrix materials ,2,3. In Here are some details of several studies on the fiber-reinforced asphalt and asphalt mixtures reinforced by BF or LF. Cheng et al.  studied Therefore, this paper considers adding BF and LF together into SBS (styrene–butadiene–styrene triblock copolymer) modified asphalt to study the performance and strengthening mechanism of mixed fiber-reinforced asphalt (MFRA). The MFRA samples were designed using several different fiber mix ratios (FMRs). Tests of softening point and ductility were chosen to study the high and low temperature physical properties of MFRA; a dynamic rheology test was chosen to study the rheological properties of MFRA; and the Scanning Electron Microscope (SEM) test was chosen to observe the micrograph of MFRA to explain the strengthening mechanism of MFRA. The conclusions of this study have certain meanings for the design of fiber-reinforced asphalt. As the influence of fiber on asphalt has a good correlation with the influence on asphalt mixture ,9, this In this paper, the SBS-modified asphalt was provided by Jiangsu Tiannuo Road Materials Technology Co., Ltd., Zhenjiang, China. The properties of it are listed in Basalt fiber (BF) is produced from natural basalt at high temperature , and theLignin fiber (LF) is made from natural wood. Various application requirements can be obtained via a series of chemical treatments to LF , during E [E is positively correlated with the length–diameter ratio and the viscosity of asphalt. Therefore, BF can better improve the viscosity of asphalt. The PH value of LF is larger than BF and they are all alkaline, which means that LF has a better chemical bonding with asphalt because asphalt is a weak acid material [The properties of basalt and lignin fibers given by the manufacturers are shown in E . The Einmaterial . It is cThe flowchart of the experiments in this study is shown in Fan et al.  conducteSoftening point was chosen to represent the high-temperature property of MFRA, and ductility  was chosen to represent the low-temperature property. The tests were conducted according to ASTM D36  and ASTMG*), phase angle (δ), and rutting factor (G*/sin δ) of MFRA were tested at 60 °C with different test frequencies.The dynamic shear rheometer used in this paper is produced by Malvern Instruments Co., Ltd., Malvern, UK, as is shown in The surface of the fiber and the fiber itself can absorb a certain amount of asphalt binder in the asphalt mixture. The oil absorption rate can affect the properties of asphalt mixtures . Within m1) is 9 grams, and put it in a beaker. (3) Put the beaker on the tray balance and press the reset button. (4) Pour 300 grams of hot SBS asphalt into the beaker and stir it evenly with a glass rod. (5) Measure the weight of the clean basket and mark it as m2. (6) Put the basket on the top of a collection container and pour the fiber–asphalt mixture all into the baskets and be careful not to make the test sample drip or drain in the testing process (the diameter of the collection container is bigger than that of the basket). (7) Put the basket along with the collection container into an oven (165 °C) for 12 h until the weight of the basket is constant. (8) Measure the weight of the basket  and mark it as m3. The asphalt (oil) absorption rate (OA) is calculated according to Equation (1).The steps of the test are as follows: (1) Place BF and LF separately into two cups, and put it in an oven (105 °C ± 5 °C) for 2 h. (2) Take BF and LF out according to the fiber mix ratio (FMR), making sure the total weight (Scanning electron microscope (SEM) used in this paper is produced by Philips company Amsterdam, the Netherlands. Micro images of different kinds of mixed fiber-reinforced asphalt (MFRA) are taken in a vacuum condition, and the fiber mix ratios (FMRs) adopted in this test are 3:0, 1.5:1.5, and 0:3 because when the FMR is 2:1 or 1:2, the micro morphology is almost the same as the micro morphology when the FMR is 1.5:1.5. The purpose of this test is to explain the strengthening mechanism of the fibers when they are combining with the asphalt. The steps of the sample preparation are as follows: (1) Prepare the MFRA sample in a mold. (2) Put it in a freezer and freeze it for 3 h. (3) Slice the sample with a clean blade. (4) Dry it in room temperature and make sure there is no water on the surface. (5) Plate gold in the vacuum coating machine . Then, tF), using Equations (2) and (3). A bigger average efficacy coefficient value (F) means a better comprehensive performance of MFRA. In Equations (2) and (3), The efficacy coefficient method (ECM) has been used by many researchers to evaluate their subjects ,30. In tIt can be seen from In the previous comparison of BF and LF properties, it shows that the heat resistance of BF is nearly 5 times higher than that of LF. With the increase of temperature, the property of LF in the asphalt is more unstable, which could lead to the decrease of the enhancement effect of fibers on the softening point. The softening point of asphalt with 3% LF (FMR is 0:3) increased only by 0.5% compared with that without fiber. The lower the FMR value, the worse the enhancement effect on the softening point will be. It can be concluded that BF can better improve the high-temperature performance of SBS asphalt.According to It can be seen that when the fibers are all LF (FMR is 0:3), the ductility of MFRA is even lower than that of SBS asphalt without fiber, and the ductility decreased by 37.5%. This phenomenon can be explained by three reasons. Firstly, the length of LF is only 13.3% of the length of BF, which could make the fibers harder to transmit the stress. Secondly, the fracture strength of LF is much smaller than BF. The total content of fibers is set as 3%, so when the content of LF is bigger, the content of BF will be smaller. This will make the fibers bear less stress in the MFRA because LF could not bear as much stress as BF does. Thirdly, LF is more likely to agglomerate in asphalt, which is consistent with the macro morphology of it, so adding LF into the asphalt might make the property of MFRA more unstable and eventually make the ductility decrease.G*) can be divided into two parts: elasticity and viscosity. A larger G* value represents the greater stiffness and the deformation resistance of asphalt. Phase angle (δ) can stand for the time lag between the stress and the strain in the test. A lower phase angle means better elasticity. The rutting factor (G*/sin δ) can be used to access the high-temperature stability of asphalt, and a higher rutting factor implies better rutting resistance. The test results of the rheological properties of the MFRA under different fiber mix ratios are shown in The complex modulus  ,30, the The result in A variety of composite interface theories have been put forward in studies about composite materials, and each theory has a certain experimental basis and can explain some experimental phenomena. However, due to the complexity of the mechanism of composite interface, the research studies on it are still very superficial. Therefore, in this section, scanning electron microscopy (SEM) was used to observe the micro morphology and interface structure of fiber-reinforced asphalt, and chemical bond theory, interface layer theory, friction theory, etc.  are adopThe micro images of basalt fibers are shown in The micro images of lignin fibers are shown in SEM was used to observe the micro morphologies of mixed fiber-reinforced asphalts (MFRA) with three different fiber mix ratios (FMRs): 3:0, 1.5:1.5 and 0:3. The micro images of these three kinds of MFRAs are shown in From The composition of fiber-reinforced asphalt is fiber and asphalt binder. When they mix with each other, they will bond together due to the action of molecular forces and chemical bonds. The mechanisms of these actions are very complex, but they will contribute to the strengthening of the asphalt . The faiG*) and the rutting factor (G*/sin δ) of MFRA more significantly than basalt fiber. FMR has more impact on the G* and G*/sin δ in higher frequency. The phase angle fluctuates with the increase of frequency, and the fluctuation range is limited.Basalt fiber improves the softening point and ductility of MFRA better than lignin fiber. A lower FMR value will cause a worse enhancement effect on the softening point and the ductility. Lignin fiber increases the complex modulus .The FMR is proposed as 1:2 according to the analysis by the efficacy coefficient method. The satisfactory comprehensive performance of MFRA is available when the FMR is 1:2.It was observed from the SEM images that basalt fiber and lignin fiber interweaved with each other and lignin fiber wound around the basalt fibers, which formed a more stable three-dimensional network structure to make the mixed fibers hold more asphalt and eventually improve the performance of MFRA.After conducting a series of studies on the performance and strengthening mechanism of mixed fiber-reinforced asphalt with different fiber mix ratios, the following conclusions can be drawn:


This study experimentally investigates the field-dependent Young’s moduli of soft composites, which are fabricated from two different magnetic-responsive materials; magnetorheological elastomer (MRE) and magnetorheological fluid (MRF). Four factors are selected as the main factors affecting Young’s modulus of soft composites: the amount of MRF, the channel pattern, shore hardness and carbonyl iron particle (CIP) concentration of the MRE layer. Five specimens are manufactured to meet the investigation of four factors. Prior to testing, the scanning electron microscopy (SEM) image is taken to check the uniform dispersion of the carbonyl iron particle (CIP) concentration of the MRE layer, and a magnetic circuit is constructed to generate the effective magnetic field to the specimen fixed at the universal tensile test machine. The force–displacement curve is directly measured from the machine and converted to the stress–strain relationship. Thereafter, the Young’s modulus is determined from this curve by performing linear regression analysis with respect to the considered factors. The tunability of the Young’s moduli of the specimens is calculated based on the experimental results in terms of two performance indicators: the relative percentage difference of Young’s modulus according to the magnetic field, and the normalized index independent of the zero-field modulus. In the case of the relative percentage difference, the specimens without MRF are the smallest, and the ones with the highest CIP concentration are the largest. As a result of comparing the normalized index of each factor, the change in shore hardness and channel pattern have little effect on the tunability of Young’s moduli, and the amount of MRF injected and CIP concentration of MRE have a large effect. The results of this study are expected to provide basic guidelines for fabricating soft composites whose field-dependent Young’s moduli can be tuned by several factors with different effects. It is well known that smart fluids, such as electrorheological fluids (ERFs) and magnetorheological fluids (MRFs), are highly effective for various applications, including automotive damper and vibration control of flexible structures. ERFs consist of fine nonconducting particles and carrier liquids, and their apparent viscosity heavily depends on the electric field that is applied to the fluid domain. Thus, an ERF is generally utilized as a core layer of sandwich structures  to increase the damping property or alternate the modal characteristics, such as the natural frequency, of the original structures ,2,3. HowRecently, as a method of increasing the tunability of the Young’s moduli of MRE, a soft composite that used a different method from that of adding an additive to the MRE matrix was suggested. The suggested method introduced in  sought tFour factors are selected as the main factors affecting the tunability of the Young’s moduli of soft composites: the amount of MRF, the channel pattern, shore hardness and carbonyl iron particle (CIP) concentration of MRE layer. To compare the effect of each factor, five types of specimens were prepared, and the overall specimen production process was similar to the previous paper , but oneThe MRE is one of the materials whose physical properties change according to the magnetic field. When the magnetic field was simulated, the shear modulus of the MRE generally changed in a short time ,27. In tThrough the finite element method (FEM) for magnetic field analysis, the effect of the magnetic field was confirmed to be concentrated at the edges and cusps of the pattern, and the average magnetic flux densities acting on the rhombus and rectangle shapes were similar. Additionally, because the magnetic flux was concentrated in the MRF, which exhibited relatively higher permeability than MRE, the MRE walls, separating the chambers, could be neglected in the MR effect. However, because the presented patterns with different cross-section coefficients could not be directly compared, the effects of the patterns were compared experimentally. To evaluate the effect of the shore hardness, which determined the properties of the rubber material, MRE was produced by setting the shore hardness to 30 and 70 and adjusting the ratio of the hardener and silicone rubber. Additionally, to compare the properties of MRE responding to the magnetic field, the proportion of CIP, combined with silicone rubber, was produced, at 40 and 80 wt.% (weight percent), respectively. Therefore, these comparative experiments with the patterns, sizes, shore hardnesses, and CIP content could be a good reference for future studies of soft structures combining the MRE and MRF.The scanning electron microscopy (SEM) images clearly reveal that CIP was evenly distributed in the mixing process a. An anaWhen attempting to achieve the uniform properties of the soft composites, several steps of bonding were emphasized. Firstly, through the pressing process, the MRE layers of different sizes, pattern shapes, CIP contents, and shore hardnesses were obtained a. ThereaTo measure the change in EYM of the soft composites according to the magnetic field, an experimental setup  was estaFive groups of specimens were selected to compare the effects of shore hardness, pattern shape, CIP concentration, and MRF amount on the change in EYM. The adopted specimen groups were 140 × 25 × 2, shore hardness of 30, CIP of 40 wt.%, and a rectangular pattern type, which was also the reference specimen group; 140 × 25 × 2, shore hardness of 70, CIP of 40 wt.%, and a rectangular pattern type that differed only in hardness from the reference specimen group; 140 × 25 × 2, shore hardness of 30, CIP of 40 wt.%, and a rhombus pattern type with only a different pattern shape; 140 × 25 × 2, shore hardness of 30, CIP of 80 wt.%, and a rectangular pattern type that differed only in CIP concentration; and finally, a group of specimens without MRF, under the same conditions as those of the reference specimen groups. Each specimen group was numbered as follows for easy identification:Group 1 (Reference): 140 × 25 × 2, shore hardness of 30, CIP of 40 wt.%, and a rectangular pattern;Group 2: 140 × 25 × 2, shore hardness of 70, CIP of 40 wt.%, and a rectangular pattern;Group 3: 140 × 25 × 2, shore hardness of 30, CIP of 40 wt.%, and a rhombus pattern;Group 4: 140 × 25 × 2, shore hardness of 30, CIP of 80 wt.%, and a rectangular pattern;Group 5: 140 × 25 × 2, shore hardness of 30, CIP of 40 wt.%, and a rectangular pattern without MRF.Tensile experiments were conducted for the selected specimen groups with the following conditions and procedures: the tensile speed was fixed at 500 mm/min based on American Society for Testing and Materials (ASTM) D412 , which ith group, calculated by Equation (1):th group, respectively. The second was the normalized index  and presence (field-induced EYM) of a magnetic field, was estimated for each specimen by performing a linear regression analysis. Two performance indicators were employed to analyze the results. The first was the general evaluation index, Through the calculation of In analyzed . FurtherTo summarize, all the groups exhibited an increase in EYM when a magnetic field was applied. By varying each factor, On the other hand, the values of articles . As the In addition, the main cause of the increase in normalized index due to the increase in the amount of injection of MRF is not only the interaction energy but also the mobility of particles. As the number of CIPs per volume increases due to the injection of MRF, the distance between particles becomes small, and the CIP included in MRF has a relatively higher degree of freedom than the CIP included in MRE. Thus, it can move and form a chain. The formation of this chain can be observed in SEM images at the interface of MRE and MRF refer to b. This iHowever, the limitations should be noted. In order to clearly distinguish the effect of each parameter from the influence of the deviation of the specimen, an approach to apply a massive magnetic field of 0.4 T was attempted. Since a large magnetic field of 0.4 T is difficult to implement in compact applications adjacent to the human body, the soft composite should achieve a stiffness change in a small magnetic field in practice. To achieve a large stiffness change in a small magnetic field, soft composites need to be optimized based on the normalized index discussed in this work and the behavior of the optimized soft composites should be explored in the small magnetic field.In this study, soft composites, consisting of MRE and MRF, were fabricated to investigate the field dependent tunable EYM. In particular, to identify the most significant factors that could affect the change in EYM, several soft composite samples were fabricated in consideration of several parameters: different magnetic field intensities, different MRF amounts, different shore stiffnesses of MREs, different CIP concentrations of MREs, and different patterns of the void channels of the lower skin layer, which was to be filled with MRF. The CIP distribution of the produced MRE and the interface of MRE and MRF were observed through SEM imaging. The universal tensile test machine and magnetic circuit for the uniform magnetic field were configured, and the force–displacement behaviors of the specimens with and without the magnetic field were determined. The overall experimental data were transformed into stress–strain relationship data to estimate EYM. By varying some factors, the relative percentage difference of EYM, according to the magnetic field, could increase up to 216.36%. As a result of normalizing the effects of each factor, based on the reference group, the MRF amount had the greatest effect on the change in EYM with the magnetic field, and the shore hardness of MRE was barely related to the change in EYM with the magnetic field. More specifically, the calculated normalized index of the MRF amount, the CIP concentration of MRE, the channel pattern, and the shore hardness of MRE were 4.96, 4.16, 1.16, and 1.03, respectively. Finally, future research should be devoted to figuring out the behavior of soft composites in the low magnetic field region in order to effectively realize the soft composite in various applications.


Rottegrade class IV-V) was achieved after about four months in SHC and after two months when using the combined DC-SC system, if the right conditions of moisture were maintained. The chemical quality of the compost produced was compatible with Class A of Spanish legislation  and the C/N ratio ranged from 9 to 15 depending on the relation BWUC:GrW.The amount of biowaste generated by university canteens (BWUC) in the faculties of the University of A Coruña (UDC) varies between 6 and 100 kg/day. In addition, the gardening services of the campus generate even higher amounts of garden waste (GrW), including pruning, which, once crushed, serves as bulking material for composting the biowaste from the canteens. Decentralized composting has been chosen with the aim of producing high quality organic fertilizers for university urban gardens while reducing the environmental burdens of both waste management and agricultural practice. Small static home composters of 340 L (SHC) for smaller amounts of generation (up to 20 kg BWUC/day) were used, while, for faculties of higher generation (up to 40 kg BWUC/day on average), the first composting stage was carried out in a closed and dynamic composter (DC). The dynamic composter was designed and built specifically for this project and its features were improved and optimized throughout the study. The pilot project was carried out in two centers of the UDC, which are known as the Philology Faculty (PF) and the School of Architecture (SA). All the organic waste generated by the canteens of these two colleges from January 2011 to July 2011 (approximately 3000 kg) was treated. Composting in SHC included a thermophilic phase that extended one month beyond the loading period for which thermophilic temperatures were also recorded. The use of the DC as the first stage in combination with static composters (SC) for the maturation stage reduced the overall thermophilic phase to 6–8 weeks. The complete maturation ( The production of quality compost from waste and other organic materials treated locally, at the source, has become an important objective for the sustainable and efficient management of urban solid waste and the conservation of soils. Local composting promotes better environmental conditions in the area, the creation of local jobs related to circular economy, and citizen awareness about waste reduction and recycling ,3,4,5,6.During the last 10 years, the decentralized and local management of biowaste has been applied as a real and complete alternative to the models based on collection and transportation. It is very common in the Basque Country (Spain) where many municipalities developed these models as their only option for biowaste treatment with good social, environmental, and economic results ,6. OtherCurrently, local composting is spreading in university campuses, not only as an environmental measure for waste management but also with educational, dissemination, and awareness proposals ,15,16. CThe main campus of the University of A Coruña (UDC) is located Elviña-A Zapateira, within the limits of A Coruña city  and conserves areas that still maintain traditional agriculture practices. The UDC set out to contribute to value and preserve this rich heritage and, to this end, the UDC has run a project of urban vegetable gardens since 2013 intended for the cultivation by the members of the University, with both students and staff. The use of these vegetable gardens required high quality organic fertilizers, which must be locally produced in order to guarantee sustainability. The rate of compost addition to maintain soil organic carbon content under Galician conditions was estimated at between 4 and 7 t/ha (dry weight), while, up to 16 t/ha, would be required to reach the desirable 3.5% soil carbon . Needs wOn the other hand, different types of organic waste are generated at the UDC campus. These includes pruning, grass cuttings, and other vegetable wastes, as well as kitchen and food waste from various university canteens. All of these organic wastes can be the subject of a joint management and treatment process, in order to produce soil amendment and high quality organic fertilizers. This configures an ideal situation in which two of the goals of the UDC’s sustainability policy are realized: the dissemination and promotion of local-traditional and organic agricultural practices and the sustainable management of organic wastes.Most of the published research about small-scale composting related to treatment volumes like household composters have been done under operation conditions that are completely different from the normal ones. Composters have been filled at once, watering and turnings have not been done at the adequate frequency, the organic waste is brought from waste treatment facilities to assure it has enough quantities to initiate the experiments, thermophilic temperatures have not been achieved, etc. ,24,25,26The general objective of this study focused on developing a decentralized composting system for organic waste from university canteen residues placed near each facility. The development of a technology adapted to the needs of the UDC was sought, dependent on the quantities of organic waste generated and other local conditions, which are feasible from the different logistic, economic, and environmental points of view. The investigation has addressed the following particular objectives.To quantify and characterize the organic waste of university canteens generated in some centers of the UDC.To define an optimum ratio between biowaste generated by university canteens (BWUC) and crushed garden waste fraction (GrW) used as a bulking agent. The proportion experimented initially was 1:1 , and, later, other relationships were tried.To establish the operating routines in two different scenarios: (a) Low generation of BWUC and composting through static home composters (SHC), (b) Medium-high generation of BWUC and application of a dynamic composter (DC) as the first stage.To determine the stability of the compost, the time-scale of the process and the different stages to achieve it.To determine the quality of the compost.The University of A Coruña (UDC) involves a population of about 20,000 people, including students and staff. The university activities take place in 20 study centers as well as in another 24 buildings dedicated to research and administration. The UDC comprises eight different campus locations, accounting for a total area of 56 ha. The main campus of the UDC is Elviña-A Zapateira and includes 10 study centers and six research centers in a 41.5 ha area. At the moment of the study, 11 cafeteria-canteen services were located in this campus area.In the first phase, a survey was carried out in 2009 on those responsible for the university canteens in order to estimate the amounts of organic waste generated in them. The survey was answered by all the services of the Elviña campus (5) and the A Zapateira campus (4). Questions were related to the number of meals served each day of the week by sections to the existence of selective collections and to the volume of organic waste generated. The questionnaire used asked for the amount of generated waste, starting from a minimum of 50 L, and for the qualitative composition of the residues  for two of these university canteens, a daily inspection of the residues was carried out in terms of the quality of the separate collection and determination of the weight and volume of the quantities generated. The obtained data allowed us to prove the validity of the questionnaire used.In the Philology Faculty (PF), three SHC of 340 L (Container KOMP 340 model) were used. Every day, the BWUC and the bulking agent were added to one of the composters and this material is mixed manually in the same composter. This mixing only affects the newly added organic materials and that of the two last additions, which limits the action only to the top of the composter. The loading process of one of these composters extends for a period of between 1 and 2 months, and, during this period, one or more full turns to mix all the material was carried out. The composter is fed until it is full. When this happens, the operation of a second composter that will receive fresh waste begins, and the process was followed as in the first composter. After an initial composting period in the first composter, when the temperature dropped at least to the mesophilic range, the material was transferred to a third composter for the maturation stage. In this way, an additional and complete mixture of all the material from the first composter and the correction of the moisture were realized and the process continued until total stabilization. The first composter was empty to receive fresh waste once the second composter was full. If necessary, the moisture content was corrected throughout the process by manual watering.In the School of Architecture (SA), a DC was used as the first stage of the process . The dyn3 and 40–80 kg/day.A capacity of approximately 1.5 mAutomatic and programmable system of mixing and advance of the material by the action of an endless spiral (turn over) powered by an electric motor.Loading entrance and unloading exit.2, moisture content, etc.)Pre-installation of sampling points for measuring the process conditions .The DC was loaded daily or every two days with fresh waste along with the bulking agent material. Mixing and aeration mechanisms were regulated with electronic timers. A mixing frequency of every 1–2 h was applied in the DC, which provided an intense axial mixture and the longitudinal advance of the material following a piston-flow behavior. The estimated retention time of waste within the digester was about 10–20 days, as estimated from punctual measurements.The pre-digested material removed from the dynamic digester goes to a static composter (SC) of 1050 L (Container KOMP 1050 model), or to a plastic mesh bag of 800 L (big-bag) where thermophilic temperatures are still reached for several days, to continue with the maturation stage at decreasing temperatures. This unit was named as a static maturation composter (SMC), which refers to both the KOMP 1050 and the Big-Bag. If necessary, the moisture content in SMC units was corrected throughout the process by manual watering.In the SA, the process was monitored for approximately four months. In the first month, the operation of the dynamic composter was evaluated in its initial configuration (DC1). In configuration DC1, the reduced power of the mixing and advancing system limited the use of the digester volume to below 50% of its capacity. After this period, the power of the engine was increased and the new Configuration 2 (DC2) was used continually for three months in order to obtain steady state operational parameters.For a better and greater understanding of the processes in the dynamic composter, the operation of the dynamic composter in configuration DC1 was compared with the initial operation of a static composter, both working in parallel under similar conditions of loading rates and waste composition. To this end, the Container KOMP 1050 model, a common static composter of 1050 L (SC1050), was used. Throughout the first 29 days of the experiment, the same fresh material (fresh BWUC from the SA mixed with GrW at the ratio of BWUC:GrW 1:1 in volume) was provided to the DC1 and the SC1050. The amounts fed during this period were 285 kg to the dynamic digester, and 283 kg to the static composter in both cases with a density of 0.46 kg/L. In this way, the total volumes of the mixture added were 617 and 614 L to the DC1 and SC1050, respectively. The operation of the DC1 was carried out as described in In addition, samples from the DC2 working at the steady state were compared with samples from the SMC composter that received the material from the DC, after a long maturation phase carried out through vermicomposting.This comparison aimed to shed light on the process characteristics in the DC1 and to determine the distance to a more stable and mature compost. The physical properties of material in process in both the dynamic and the static composters were determined, including basic parameters such as the content in volatile solids (VS) and moisture content (MC). Other parameters were obtained by the suction table method described below . These wLastly, several derived parameters, that is, particle density (PD), total porosity, or void space (ϕ), air capacity (AC), and free air space (FAS), were obtained through the following equations ,28.PD =Rottegrade test (Dewar Self-Heating Test) and by respirometry [The temperature of the material in composting was routinely determined at three points of each mass to obtain the average value. Oxygen in the interstitial atmosphere was determined in two points both in the DC and in the static composters SMC and SC in the SA. Moisture was routinely qualitatively checked, and MC was occasionally tested in the laboratory. On the other hand, samples of both the compost and the raw materials (bulking agent and BWUC) were collected for the determination of different parameters. Analyses of the final product were also performed to determine their quality . The volume of leachate generated in the DC was also determined. Stability in the intermediate stages of the process and the final compost samples was determined by the irometry .2O3 and AgCO3O4. After combustion, the resulting gases passed through a reduction reactor containing elemental copper at 650 °C. After removal of water, the evolved N2 and CO2 were separated by gas chromatography and detected by thermal conductivity. All samples were analyzed in duplicate. The quantitative analysis of metals was performed in triplicate in samples of 0.5 g  by adding 10 mL of distilled cc HNO3 and heating to 175 °C for 10 min, according to the US EPA 3051A method [MC was determined by drying to a constant weight (24–48 h) in an oven at 90 °C and volatile solids (VS) by ignition at 550 °C (4 h). The analysis of the nitrogen content (N), total carbon (C), and total organic carbon (TOC) were performed on an EA1108 elemental analyzer  equipped with an AS200 autosampler. For nitrogen and carbon analysis, samples were weighed in tin capsules. For organic carbon analysis, samples were weighed in silver capsules and carbonate was removed by addition of HCl before the analysis. Samples were oxidized by combustion at 1020 °C using an oxidation catalyst containing CrPhysical properties of the material in process were determined using a suction table with a sand bed , where pi is the concentration of metal i in sample compost and CAi is the concentration limit of metal i for Class A in the Spanish regulation (RD 865/2010 and RD 506/2013).In order to facilitate interpretation, relative heavy metal (HM) values are defined as the ratio of the metal concentration in the compost sample to the Class A regulation limit .Relativ2), the statistical F-value, and the probability (p). Statistical analyses were carried out in Microsoft Excel .Unless otherwise stated, mean and standard deviation values were used to assess the characteristics of compost samples. The suitability of the least-squares fit (linear regression) was evaluated by the square of the coefficient of determination  showed the following results :These results show a 32% higher generation in SA and a 23% higher generation in the case of PF, in relation to the estimate made two years earlier. Regarding the type of organic material that constitutes BWUC residues, food leftovers were predominant  while waste from food preparation, squeezed oranges, and coffee grounds were usually present but in variable amounts depending on the center (0–37%). In this way, the processed food always remains as the majority fraction, while other types of materials show a very variable presence. The presence of inappropriate materials such as plastic and metal, mainly bottle stoppers, plastic wrap, sauce, and condiment bags or kitchenware) was measured and was very rare or sporadic. Physical contaminant materials was always far below 1% of raw material.The chemical composition of the waste materials used for composting is presented in The experimental study in the Faculty of Philology lasted for eight months. During this period, three successive composting batches were carried out, in accordance with the process described in According to these results, a three-stage process was proposed as indicated in ®, several preliminary tests were performed to demonstrate the performance of all operating mechanisms, including mixing and ventilation functions. Ventilation was found to be necessary not only for oxygenation, but mainly to remove excess water vapor that otherwise condensed and generated leachate and excess moisture from composting material. In addition, it was considered necessary to shorten the width of the spiral blades to avoid the excessive mixing effect and excess effort required to move the endless spiral of the digester. The DC was then continuously operated for one month , a maximum retention time of 14 days was obtained and the system could not receive more than 10 kg/day of organic waste.The SC1050 was operated in parallel with the DC1 described in Correcting this initial design of the DC1 would require greater capacity and power to its mixer system. Modifications carried out affected the mixing mechanism and the torque of the engine. These changes allowed to reach about 400–500 kg inside the digester. These conditions were applied from the fortieth day of operation forward A,B, reacRottegrade class II-IV.Under the new configuration during this second period (days 42 to 107), a total of 1291 kg (2809 L) of BWUC and GrW were fed into the DC2 at a rate of 19.6 kg/day on average. The DC2 achieved a mass reduction for the material in the process of about 35.7%, which generated an outlet rate of 12.6 kg/day that was transferred to the SMC. In this condition, the DC2 reached temperatures in the range of 41–54 °C (47.4 ± 6.3 °C on average), which favored the composting process. The material taken out from the digester, in terms of stability, shows a variable Rottegrade class IV-V was obtained after 3–4 weeks in the SMC when the DC2 is used as the first stage.The material taken out from the two reached thermophilic temperatures of 52–59 °C in the SMC for 2–3 weeks (the batch in n = 15) in the period of low load (days 1–21) and 14.1 ± 3.2% (n = 42) in the period of high load. Static composters showed 19.4 ± 2.2% oxygen on average  and 20.0 ± 0.7% .In general, a good oxygenation of the material in composting was observed, both in the DC2 as especially in the SC and SMC . The low3·day (18.5 kg BWUC/m3·day on average). With these high loads, during the autumn, the discharge of the digester was made directly to a big bag in which the maturation continues for a period of 3–5 weeks, and becomes, after this period, stable compost. The use of the big-bag facilitates the draw out of compost and transportation to the area of use as well as traceability of the batches.Subsequently, all the BWUC of the SA was fed into the DC2, which allowed checking its operation with loads of up to 40 kg/day. The mean loading rate in the autumn 2011 (October to December) was 28 kg BWUC/day, showing similar operating characteristics and results. Thus, the treatment capacity of the DC2 was in the range of 13–27 kg BWUC/mEarthworms were applied to some SMC batches after the end of the thermophilic phase, which required a period of several months and periodic supervision to maintain high moisture with the need for watering during the summer months.The physical characteristics of different samples from the dynamic and static composting units are shown in Regarding the evaluation of physical properties of compost samples , the val29 sample in order to better verify the differences. The results are shown in p < 0.05) was 12 without the DC129 sample and 11 including it. The main differences were found for the parameters BDdry, BDwet, ϕ, and AC. Significant correlations of DBdry with FAS or with MC without DC129 sample as well as for ϕ with PD and with VS was lost when this sample was included. The opposite occurred for the correlation of ϕ with DBdry, DBwet, and AC.Thus, the correlation between variables was performed with all data and excludes the DC1Cases of nonlinear correlation were obtained for some parameters. In fact, BDwet and WHC increased and AC decreased in a linear manner with MC up to 65% and then continued to vary while MC asymptotically approached the limit value of 70%. Thus, other factors than MC determined the behavior of these parameters. The same behavior was observed for these variables against FAS for which the asymptote was the lower value of 28% FAS. This was due to the strict linear relation between FAS and MC in the operating conditions.dry and BDwet, and WHC, while showing low AC and FAS values. Among these parameters, only low FAS was explained by the high MC, while the others were on the asymptote for MC . Configuration DC2 improved these properties that approached those obtained for static composters (SC1050 and SMC). DC1 samples showed a greater compaction of the material, which was indicated by lower contraction capacity, and lower AC values, giving the material a mushy appearance that disappeared in configuration 2 (DC2). In fact, with the change in configuration, the AC increased from values below 35 to values above this threshold, which was indicated as convenient for composting [In the initial configuration DC1, the material had the largest bulk densities, BDmposting  and simiAll the samples analyzed had high or very high ϕ values . Compost2 < 0.11), and there is no difference between DC and SC samples, even though the values increase with composting time in both cases. It was in the 5% to 14% range, so it may be considered low but appropriate.Cv does not correlate with any of the other variables . The values of FAS obtained for the SC samples were above the optimal range (30–35%) proposed for composting [FAS correlated strictly with MC  was very rare or sporadic, which was always far below 1% of raw material. The obtained results also emphasize the satisfactory participation of the different agents involved, from the staff of the cafeteria services, to the gardening company. The total of the organic waste generated in these two centers, just over 5000 kg in 2011, together with approximately another 2000 kg of crushed plant remains, has been transformed into compost. The obtained compost was used as fertilizer in the university vegetable gardens cultivated by students and staff.Once the system had been implemented, the personnel in charge of the supervision of the equipment and composting areas dedicated 1 h a week to each composting area. This included students with environmental scholarship, combined later with job placement workers provided by a charitable non-governmental organization. The composting process in static composters has been evaluated as simpler for reduced amounts of organic waste generated by university canteens, up to 15–20 kg/day. In this range of operations, in the following years, new composting areas were installed in which static composters of different volumes were used, which varied from 340 to 1400 L. At the end of 2019, nine composting areas were in operation on the UDC campuses, which treated approximately 80% of the BWUC generated . For higAs suggested by Valentukevičienė et al. , these oThe operation of the static composters was very simple and reliable when the bulking agent was of a suitable and homogeneous particle size as used in these experiments. The system is feasible for the treatment of amounts up to 20 kg/day of organic food waste dedicating 1 h of labor per week. For higher amounts of waste, the use of the dynamic composter that favors the mechanical and automatic mixing of the waste and the bulking materials was considered desirable. This dynamic composter also accelerated the thermophilic fermentation stage.3·day.In this study, the limitations of the dynamic composter in its initial configuration were identified and several improvements have been proposed and applied to achieve thermophilic temperatures. In the initial configuration, low temperatures and high moisture content appeared to cause higher bulk densities and very low free air space. These features were compatible with an acceleration of the process caused by a rapid hydrolysis and reduction of the particle size in the dynamic composter. When the load capacity of the dynamic composter was increased, these parameters improved and approached those of the static composters but maintained the effect of the dynamic composter on the process acceleration. The treatment capacity of the dynamic composter stood at the range of 13–27 kg BWUC/mRottegrade class IV-V was obtained after 5-8 weeks when the dynamic digester is used as a first stage, and, after 3–4 months, when only static home composters are used. The final compost demonstrated a high-fertilizing power with nitrogen content of 2.5–3.6% and C/N ratio of 11–15 depending on the proportion of the bulking material to waste used. The concentrations of heavy metals were low, so the compost can be classified as a Class A, according to current regulations. Cadmium, which is present in food waste, was located near the limit value of class A so that a process with a low proportion of bulking material combined with a very advanced reduction of organic matter could lead to values exceeding the limits of class A.The study established the routines and minimum times of operation depending on the different systems used. Stable compost of


The preparation of continuous layers of highly hydrophobic pure silica ITQ-29 zeolite, potentially applicable as hydrophobic membranes for separation of molecules based on their polarity, has been investigated. Continuous layers of intergrown ITQ-29 zeolite crystals were successfully grown on porous alumina supports by optimization of the synthesis conditions, such as the appropriate selection of the seeds, the procedure for the gel preparation, and the calcination conditions. This resulted in the formation of all silica ITQ-29 zeolite layers without the presence of germanium required in previously reported ITQ-29 membranes, with the subsequent improvement in quality and stability, as verified by the absence of cracks after calcination. We have proved that the incorporation of aluminum from the support into the zeolite layer does not occur, neither during the secondary growth nor through migration of aluminum species during calcination. The production of platform molecules from renewable sources has been pointed out as an alternative to the use of petroleum due to the growing interest on low-carbon technologies. Butanol arises as a very versatile molecule, not only as excellent biofuel, but also as a reactant for the preparation of important industrial chemicals . When n-4 and AlO4, are linked by sharing oxygen atoms and assembled into secondary building units such as cubes, hexagonal prisms, octahedra, etc., generating a vast variety of microporous structures accessible through different types and sizes of windows to pores and cavities of molecular dimensions. At present, there are more than 260 different zeolitic structures, as it is reported in the database of the International Zeolite Association that collects all related information and ascribes a three-letter code to each structure [Zeolites are crystalline microporous aluminosilicates in which the silicon and aluminum tetrahedra, SiOtructure . A pure tructure ,13.Zeolites can also be synthesized in different appearances, crystal sizes, and shapes, being also possible to grow them into a continuous intergrown membrane . There aPure silica zeolite membranes have attracted interest for decades because of their hydrophobicity and high thermal and chemical stabilities, and they have proved potential applicability to carry on organic/water separations, being Silicalite-1 zeolite the most studied ,17,18,192 adsorption, making this zeolite a suitable adsorbent for natural gas upgrading, due to its high regenerability and adsorption capacity of CO2 over CH4 [The polarity of zeolites can be finely tuned by controlling the Si/Al ratio in the framework. For instance, the small pore zeolite with the code LTA (Linde Type A) can be obtained in the whole range of Si/Al ratios, thus covering the widest range of polarity, from the very hydrophilic Si/Al ratio of 1 in zeolite A , to the over CH4 ,26. Alsoover CH4 , but in over CH4 . More reover CH4 . The hydover CH4 , vapor aover CH4  and moleover CH4 .A first approach to the preparation of ITQ-29 membranes was done on porous tubular supports, but using germanium in the synthesis gel, resulting in Ge-ITQ-29 zeolite , because2 and N2. In this case, LTA zeolites with Si/Al ratio of 5 [2 was considerably improved by increasing the zeolite loading into the polymer membrane. Nevertheless, in the case of mixed matrix membranes the compatibility between the polymer membrane and the selective filler is of crucial importance and the zeolite is unevenly distributed along the membrane.The preparation of pure silica ITQ-29 thin films on silicon wafers was also reported via the fluoride-assisted synthesis in vapor phase to produce low dielectric constant materials with potential interest in the semiconductors industry . Finallytio of 5 ,34 and ttio of 5  were useTherefore, we decided to go one step forward in the preparation of pure-silica ITQ-29 membranes on porous ceramic supports with the objective of preparing continuous pure silica zeolite ITQ-29 layers free of cracks. A key aspect to take into account during the membrane growth is to ensure an appropriate contact between the seeded support and the synthesis gel. It becomes critical when using a solid synthesis gel such as the one used for the standard preparation of ITQ-29 zeolite which is done in fluoride medium from a highly concentrated gel. So, the gel preparation procedure was modified in order to increase the gel viscosity. Besides, we decided to use other type of support and planar alumina discs were selected with the aim of decreasing as much as possible the strains between the zeolite layer and the support during calcination.In this context, we propose the use of an ITQ-29 zeolite membrane grown on porous alumina supports as an appropriate candidate for the separation of bioalcohols from fermentation because of its very high hydrophobicity.First, the synthesis of the seeds to be used in the preparation of the zeolite layers on the alumina supports was optimized with the aim of controlling the crystal size. Thus, the influence of the synthesis duration and the synthesis procedure  on the size and crystallinity of the ITQ-29 zeolite was studied herein. The purity of the ITQ-29 samples was confirmed by X-ray diffraction (XRD), all of them are pure LTA zeolites with high crystallinity, as can be seen in 2 for ITQ-29 and Silicalite-1, respectively. This fact is a clear indication of the very hydrophobic character of ITQ-29 zeolite, even surpassing that of Silicalite-1, reported as a hydrophobic material. As a comparison, the heat of immersion in water of a hydrophilic material, such as the ordered mesoporous MCM-41, gives a value of 135 mJ/m2. The very high hydrophobicity is attributed not only to the lack of charges due to the pure silica composition, but also to the absence of internal silanol defects on the ITQ-29 zeolite [The hydrophobicity of ITQ-29  and the images are shown in The alumina porous supports were successfully seeded with an evenly distributed layer of 0.6 µm crystals of ITQ-29 zeolite by using the dip-coating procedure with an aqueous solution of polyethyleneimine. In 2O/SiO2 = 3) [2O/SiO2 ratio between 5 and 13. Also, the preparation procedure of the synthesis gel for the secondary growth was modified in order to decrease its viscosity and enhance the contact with the seeded alumina support. The detailed preparation method is described in Materials and Methods section, consisting basically on the evaporation of water beyond the desired composition, homogenization of the gel into a fine powder, and final adjustment of the water content to reach the required molar composition. This methodology allowed us to successfully obtain a viscous rather than solid synthesis gel.The conditions for the standard synthesis of ITQ-29 zeolite involve the use of a highly concentrated gel with low amount of water (HiO2 = 3) , and theiO2 = 3) . This lo2O/SiO2 ratios is shown in 2O/SiO2 molar ratio of 5 so, it was selected as the proper ratio. In the case of higher water content, the ITQ-29 crystals did not form an intergrown layer on the alumina surface, and these crystals can be observed attached to the support, whereas for the preparation with H2O/SiO2 = 5 a good coverage of the alumina surface with a continuous layer of intergrown ITQ-29 cubic crystals is observed  must be removed from the zeolite to open its porosity, and calcination in air was performed at different temperatures to study its impact on the membrane quality. The calcination process is a key point in the preparation of high silica zeolite membranes since the high temperature required usually produces cracks in the zeolite layer making the membrane useless for further applications. This was one of the main problems of the previously reported ITQ-29 membrane that suffered of crack formation when calcined in standard conditions and it required the use of ozone and low temperature for partially removing the organic and open the porosity without damaging the zeolite layer .The materials were calcined at 773, 823, and 873 K, and the corresponding XRD analyses are summarized in The surface of the calcined materials was analyzed by SEM to confirm or discard the formation of cracks. The images are shown in The aluminum content on the zeolite has an impact on its polarity, and it is crucial to obtain pure silica membranes to avoid olefins oligomerization during the olefin/paraffin separation, and take advantage of its high hydrophobicity during water/bioalcohols separation. For that reason, energy dispersive X-ray spectroscopy (EDX) analyses were performed on the calcined pure silica ITQ-29 membrane to study if aluminum incorporation into the zeolitic framework took place in some extent, and also to analyze the zeolite intrusion into the porous support. The selected material was prepared after 7 days of secondary growth, and calcined for 6 h at 773 K. Atomic percentages of silicon and aluminum were analyzed along the membrane, and the results are shown in In summary, these results confirm that pure silica ITQ-29 zeolitic layers were successfully grown on porous alumina supports by optimization of different parameters, such as the crystal size of the seeds, the preparation procedure, and the calcination conditions. The selection of planar alumina supports instead of tubular ones together with the modification of the synthesis procedure, resulted in the successful growth of a pure silica ITQ-29 zeolite layer on the support. In this manner, significant advances with respect to the previously reported ITQ-29 membrane are achieved. First, the presence of germanium is avoided with the consequent improvement in the stability and, in addition, the reduction of strains between the planar support and the zeolite layer together with its silica composition allows the calcination of the membrane avoiding the formation of cracks. The materials obtained consist of continuous layers of all silica LTA zeolite in which it is expected the same hydrophobic character as in the powder form and similar adsorptive properties, as long as the zeolite layer is continuous and defect-free. These materials are expected to be particularly useful for different separation processes involving olefins or bioalcohols, among others, that will be the subject of future studies.2 in the synthesis gel arises from these seed crystals. So, pure silica ITQ-29 was synthesized from a gel with the following composition:ITQ-29 zeolite seeds were synthesized from a low water content synthesis gel, according to the general procedure described in the literature . The orgThe solid synthesis gel was introduced into Teflon-lined stainless steel autoclaves. For crystallization, the autoclaves were heated at 398 K for 3.5 and 4.5 days under static conditions or continuous rotation of the autoclaves at 45 r.p.m. Then, the autoclaves were cooled down, and the solids were filtered, washed with distilled water and acetone, and dried at 373 K.50 = 1.8 µm, 3 mm thickness, and 25 mm in diameter, from Fraunhofer .Uncalcined zeolite ITQ-29 with a crystal size of 0.6 µm prepared as described above was used for seeding asymmetric α-alumina disks, with pore diameter d2-OH linkage [The alumina supports were seeded by dip-coating them into an ITQ-29 zeolite dispersion in aqueous solution of polyethyleneimine  . The zeo linkage . The supThe seeded supports were then placed facing downwards in a Teflon-lined stainless steel autoclave with synthesis gels of the following molar composition:The materials were finally calcined in static air at temperatures between 773 and 873 K for 6 h in order to remove the occluded organic structure-directing agent and expose the microporosity, with heating and cooling ramps of 1 K/min.1 = 1.5406 Å) at 45 kV and 40 mA in the 2θ range from 4 to 40°. The instrument is equipped with an X′Celerator detector and automatic divergence and reception slits (constant irradiated area of 3 mm). The affinity of the materials to water was studied by immersion calorimetry using a C80 Calvet calorimeter from Setaram . The samples were degassed in a glass ampoule with a brittle bottom and were submersed in water at 303 K inside the measuring cells. Once the thermal equilibrium was reached, the ampoule was pushed down and the brittle end was broken, thus allowing the entrance of water in the ampoule wetting the sample. The heat flow was recorded as a function of time, and the heat of immersion can be calculated as the area underneath the peak, in J/g. Scanning electron microscopy (SEM) was used to study the crystal morphology and size of the ITQ-29 powder on the one hand, and the membrane topology and thickness on the other. The membranes were broken by fracture and mounted vertically on a SEM sample holder for the side view inspection. The elemental composition of the membranes was analyzed by energy dispersive X-ray spectroscopy (EDX), allowing to investigate the silicon intrusion within the alumina support and the aluminum incorporation onto the zeolite framework. The SEM and EDX analysis was done in a Jeol JSM 5410 microscope  of the Electron Microscopy Service of the Universitat Politècnica de València.The crystallinity and phase purity of the zeolites and membranes was studied by X-ray diffraction (XRD) in a Cubix’Pro diffractometer from Panalytical , using CuKα radiation (λPure silica ITQ-29 zeolite layers were successfully synthesized on porous alumina disks by selecting the appropriate combination of crystal size of the seeds, the seeding technique, the methodology for the preparation of the gel, the duration of the secondary growth, and the calcination conditions. The water content of the synthesis gel was adjusted after the silica precipitation, hence resulting in a viscous gel rather than a solid material, thus favoring a better contact with the seeded support. In this way, continuous layers of 8 µm thickness were prepared after 7 days of secondary growth, and were activated by calcination at 773 K in air, resulting in crack-free microporous membranes. The incorporation of aluminum from the support into the zeolite layer did not occur, neither during the secondary growth nor through migration of aluminum species during calcination. The materials obtained were defect-free and crystalline, being appropriate candidates for bioalcohols separation in aqueous solutions.


Background: The search for an effective therapy for local radiation injuries (LRI) is urgent; one option is mesenchymal stem cells (MSC) derived from the placenta and their conditioned medium for the regenerative processes of the skin. Methods: We used 80 animals, randomly assigned to four groups: control (C) animals that did not receive therapy; control with the introduction of culture medium concentrate (CM); introduction of MSCs (PL); introduction of CMPL. LRI modeling was performed on an X-ray machine at a dose of 110 Gy. Histological and immunohistochemical tests were performed. Results: On the 112th day, the area of the open wound surface in the CMPL group was 6.7 times less than in the control group. Complete healing of the open wound surface of the skin in the CM group was observed in 40%, in CMPL 60%, in the PL group 20%, and in the C group there were no animals with a prolonged wound defect. A decrease in inflammatory processes was observed in the CMPL group. Conclusions: the use of a concentrate of conditioned MSCs (CMPL group) in severe LRI in laboratory animals accelerates the transition of the wound process to the stage of regeneration and epithelization. Today, ionizing radiation sources are widely used in various fields of human activity, and their scope is constantly expanding, which increases the risk of radiation damage ,2. StudiRadiation to human skin in doses exceeding 8 Gy may lead to the development of local radiation injuries (LRI) . In radiTaking into account the pathogenetic mechanisms of radiation-induced lesions, the use of cellular technologies using mesenchymal stem cells (MSCs) and their waste products (paracrine factors) may become a promising method of treating skin LRI . MSCs arThe main effect of MSCs may be due to their secretory activity, associated with the production of a wide range of cytokines and growth and angiogenic factors . ParacriOne of the most important advantages of MSCs is their low immunogenicity, which allows the use of allogeneic MSCs without the risk of rejection reactions. Sources of MSCs are various human tissues  ,3,4,6,7.Placental tissue is of great interest due to the simplicity of sampling, the absence of ethical problems, and the ability to quickly obtain and accumulate the necessary amount of cellular material. MSCs derived from the placenta are known to have a higher regenerative potential compared to cells from other sources, but there are no data on the use of these cells in LRI .Thus, the presented data indicate that MSCs derived from the placenta and the paracrine factors produced by them can be used to produce drugs intended for the treatment of LRI, which undoubtedly deserves further study.The aim of this study was to study the effect of human MSCs derived from the placenta and their conditioned medium concentrate on skin regenerative processes in laboratory animals with LRI.There were 80 laboratory animals used in the study . The animals were obtained from the specialized laboratory animal nursery Pushchino, had the appropriate veterinary certificate, and were quarantined for 14 days. The study was approved by the section of the Academic Council  and at the meeting of the local bioethical committee (Protocol No. 8b dated 10/11/2012) of the State Research Center—Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency.Laboratory animals were randomized and divided into four groups  depending on the type of therapy performed:Group 1—control (C)-irradiated rats without subsequent therapy;Group 2—control (CM)-irradiated rats that received intradermal administration of culture medium (MesenCult) concentrate around the affected area three times, on days 1, 14, and 21;Group 3—irradiated rats that received intradermal administration of human MSCs derived from the placenta (PL) three times, on days 1, 14, and 21;Group 4—irradiated rats that received intradermal administration of concentrate of conditioned medium (CMPL) MSCs derived from the placenta three times on days 1, 14, and 21.Each laboratory animal was observed 17 times: 1, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105, and 112 days after LRI modeling. During the examination, the condition of the laboratory animal was monitored with an assessment of its behavior, movement, cardiovascular and/or respiratory functions, changes in appetite and weight, body temperature, etc. On set days, the skin surface was examined and the course of the wound process was evaluated , the total area of the changed skin, the area of the open wound surface, the presence of discharge, blisters, scab, exfoliated epidermis, the color of the exposed dermis, fibrin plaque).Animals were removed from the experiment 28, 42, 56, 70, 91, and 112 days from the beginning of the experiment.Modeling of relatively “soft” X-ray radiation of LRI was carried out on an LNK-268 RAP100-10) X-ray unit  with a radiation exposure mode at a dose of 110 Gy with a 0.1 mm aluminum filter, voltage 30 kV, beam current 6.1 mA, dose rate 21.1 Gy/min for 312 s  according to the proposed earlier method [0-10 X-raThe experiment used nonpersonalized human MSCs derived from the placenta samples that are under long-term cryopreservation in a Cryobank. MSCs were cultured in a medium without xenogenic components  with the addition of 100 U/mL of penicillin, 100 U/mL of streptomycin, and 2 mm of glutamine from the 3rd to the 5th passage. The resulting MSCs were administered to laboratory animals at a calculated dose of 2 million cells per 1 kg.The MSCs derived from the placenta immunophenotype was determined by flow cytometry. The expression of surface markers was evaluated using fluorochrome-labeled antibodies against CD34, CD45, CD90, CD105, CD73, and HLA-DR  on a FACSCanto II flow cytometer  in accordance with the manufacturer’s instructions.Cell viability was evaluated using a 7-ADD dye that penetrates the cell’s cytoplasmic membrane and binds to its DNA. The number of CD45-negative/7-ADD-positive cells was determined on a FACS Canto II flow cytometer (Becton Dickinson) in accordance with the manufacturer’s instructions.The conditioned medium of MSCs derived from the placenta (CMPL) was taken into sterile tubes at 3–5 passages when the cells reached 80–90% confluence. A laboratory tangential flow filtration system, LabScale, developed for concentration, diafiltration, and microfiltration, was used to obtain CMPL. The CMPL was placed in a tangential flow filtration system and concentrated 8.08 times with an inlet pressure of 40–52 psi and an outlet pressure of 8–12 psi. The resulting volume was passed through a nylon syringe filter with a pore size of 0.22 μm . The protein concentration was 648 μg/mL, IL-6: 853 pg/mL, IL-8: 8730 pg/mL, IL-10: 17.7 pg/mL, TGF-β: 1.0 pg/mL. The volume concentrate of conditioned medium for rats of the CMPL group for each injection was 0.4 mL. The introduction was carried out intradermally up to 12 points around the irradiation zone, retreating 2–3 mm from the edge.A skin flap was excised from the affected area  and fixed in a 10% solution of neutral formalin. Further processing of excised samples was performed using standard histological methods. Preparations stained with hematoxylin and eosin were used for general assessment of the condition of the studied tissues.Immunohistochemical examination of tissue samples on days 28 and 112 of the experiment was performed using an automated method, a Ventana BenchMark Ultra immunostainer with dewaxing and unmasking in an apparatus using antibodies to VEGF , CD31 , CD68 , PGP9.5 , Ki67 , FVIII , collagens of types I and III (Novocastra), tissue inhibitor of metalloproteinases TIMP2 (Novocastra), and metalloproteinases of types 2 and 9 (Novocastra). Marker expression was evaluated semiquantitatively, assigning scores from 0 to 3, where 0 means no expression and 3 means fully expressed.Statistical analysis of the results was performed using Microsoft Office Excel 2007 , Statistica 6  and ImageTool software  was detected in all cell cultures; markers of hematopoietic and lymphocytic origin were absent . The immunophenotype met the requirements of the International organization of cell therapy for human MSCs [p ≤ 0.05)  a. Howeve ≤ 0.05) .From the 14th day of the experiment, the open wound surface of the skin was recorded in all groups of animals. The dynamics of reducing the area of the open wound surface was the same for all groups up to day 42 of the study. After that, we observed wave dynamics of increase and decrease of the open wound skin surface in all groups except CM .On day 112, the area of the open wound surface in the CMPL group was 6.7 times smaller than in the control group. Complete healing of the open wound surface of the skin in the CM groups was observed in 40% and the CMPL in 60%, in the PL group in 20%, and in the C group there were no animals with a prolonged wound defect c.In all groups, an open wound defect covered with a purulent‒necrotic crust was formed on the 28th day after irradiation. Weak, mainly perivascular lymphocytic‒plasmocytic infiltration with an admixture of single neutrophilic granulocytes and moderate vascular proliferation of the microcirculatory bed was detected in the underlying dermis in the area of the defect bottom. Moderate thickening of the adjacent epidermis was noted along the edges of the wound defect, and few intraepidermal lymphocytes were recorded. At the same time, only in the CMPL group was the “creeping” of regenerating epithelium from one of the wound edges in the form of a strip 3–4 epithelial cells thick noted .In group C, on day 56, the bottom of the skin defect reached the large subcutaneous muscle, and, in some cases, the subcutaneous fat. Pronounced edema and lymphocytic‒plasmocytic infiltration of muscle tissue were determined. In the connective tissue of the dermis in the area of the edges of the wound defect, lymph‒histiocytic infiltration with an admixture of neutrophils, granulation, and proliferation of microvessels were detected. The epidermis adjacent to the wound defect was thickened to 10–12 layers of cells, and focal hyperkeratosis, acanthosis, and degenerative changes in keratinocytes were noted. Areas of epithelial regeneration with a thickness of 4–8 epithelial cells were determined in the area of the defect edges , which indicated an increase in neoangiogenesis by the end of the experiment. Such changes were not detected in groups C and CM (p ≤ 0.05)  a.p ≤ 0.05), while in the CM group it was determined by the decrease in the number of these cells , and in the CMPL group their number did not change , and remained unchanged in the CMPL group  2 and 9, which led to the destruction of extracellular matrix proteins and stimulated cell migration and reproduction, decreased in all groups at the end of the experiment, with the exception of the CMPL group b,d, whilSkin LRIs pose a serious medical, social, and economic problem. It is known that early effects of skin damage from ionizing radiation (dry and wet dermatitis) are associated with damage to the epidermis, and late effects  are the result of damage to the dermis . Thus, tThis study is aimed at preventing complications of late radiation injuries, improving the nature of the treatment course, and speeding up the healing time of skin LRIs. The introduction of MSCs, culture, and conditioned media was performed three times: in the absence of changes in the skin (day 1), after the formation of radiation dermatitis (day 14), and after the appearance of the wound surface (day 21) to activate reparative processes and angiogenesis in damaged skin, reduce the healing time of ulcerative defects, and prevent relapses.In the course of the present study, the use of a conditioned medium concentrate and culture medium showed greater effectiveness in terms of reducing the time and area of the open wound surface. The greatest number of cases of complete healing of the affected skin of animals by the end of the observation period (112 days) was detected in the CMPL group, and healing was also noted in the CM group. In the same groups, no clinical signs of LRI recurrence were detected, but not in the C and PL groups .In our previous study , the effAccording to the histological study, there was a decrease in inflammatory processes, the presence of hair follicle rudiments, and proliferation of microcirculatory vessels in the CMPL group, in contrast to other groups in which these changes were not so noticeable.Given the nature of the radiation damage in all groups, the regenerative potential of cells in the affected area is significantly reduced, which was confirmed by data from immunohistochemical research. An increase in the expression of metalloproteinases (MMP 2 and 9), TIMP 2, collagen I and III, as well as the number of CD68 macrophages, was observed in the CMPL group on day 112, which probably indicates an increase in the rate of scarring and healing of the wound surface, which is confirmed by planimetric studies a,b.Thus, the use of MSCs derived from the placenta conditioned medium concentrate (CMPL group) in severe LRI in laboratory animals accelerates the transition of the wound process to the stage of regeneration and epithelization. Interestingly, in one of the control groups, when using a culture medium concentrate (CM group), a significant decrease in the area of the wound surface was observed compared to other groups during the entire observation period. However, the analysis of histological and immunohistochemical studies does not allow us to unequivocally assert the effectiveness of this type of therapy.


The spacing factor, in turn, was below 0.200 mm (L = 0.185 mm). The example of the A6 motorway renewal project served to demonstrate that reclaimed concrete aggregate, obtained by crushing the entire pavement, can be used for production of the new pavement courses.This article presents the results of fatigue testing and assessment of the mechanical and physical properties of the concrete pavement of the A6 motorway, which was put in service in 1938. After 82 years of operation under heavy traffic loading conditions, the pavement was fully recycled by crushing of the existing concrete and reuse of the reclaimed material in the new courses of pavement placed as part of the motorway renewal project. The main objective of this research was to determine the properties of the tested concrete, including compressive strength, water absorption and freeze-thaw resistance after 150 cycles of alternate freezing and thawing. The resistance of the concrete to the action of de-icing products was also checked. The article also presents the results of petrographic analysis of the aggregates. Additionally, concrete sampled from the pavement was evaluated for freeze-thaw resistance in relation to the determined porosity characteristics. The tested concrete, which was subjected to over 80 years of traffic loading on the A6 motorway, was found to meet the highest requirements as currently applied for the extra heavy-duty pavements. With a compressive strength value in excess of 50 MPa, the tested concrete can be rated at least CC40, according to EN 13877-2:2013-08. The samples were found to satisfy the freeze-thaw resistance requirements of an F150 rating. The air void analysis showed that the analyzed concrete contained 1.6% of micropores, i.e., air voids smaller than 300 μm (A Recycling offers several ways to utilize the qualities of old concrete. As one of the available options, recycled concrete materials can be used for production of new concrete ,2,3. So In comparison to other modern concrete recycling methods , this mainly avoids the additional costs associated with separating the aggregate from the adjacent hardened cement slurry (paste). In addition, there is no problem in the management of small fractions of concrete debris that are a by-product of these technologies and contain a significant amount of hardened cement slurry (paste).2 emission and, besides, reduces the cost of the road construction works. In the authors’ opinion, the material obtained from the analyzed over 80-year-old pavement features very good strength properties, which are accompanied by an adequate freeze-thaw resistance and homogeneity.The objective of this research is to evaluate the properties of the over 80-year-old concrete pavement and to confirm the possibility of reusing the recycled material as a quality aggregate for new built or renewal projects. The in-place recycling of the concrete pavement to obtain a quality aggregate brings major environmental benefits, including reduced extraction of natural aggregates and reduction of COThe analyzed section of the concrete pavement between the interchanges Szczecin Dąbie and Rzęśnica was built in 1938 as part of the Reichsautobahn (RAB) No. 4 motorway expansion scheme of the pre-war Germany, which was planned to connect, in the final layout, Berlin in the west with Gdańsk in the east, reaching up to Kaliningrad (Königsberg). Currently, it is part of the A6 motorway on the European route E28, linking the north-western part of the Polish road network with the German road network. In addition, it serves also as the southern by-pass of Szczecin. On this section, the A6 route coincides with the route of the S3 expressway (trunk road) heading to Świnoujście, Poland. It is worth mentioning that the operated section of the A6 motorway is at present the only concrete paved road section among the national highways in the Western Pomerania region of Poland.During the over 80 years of operation no renewals were carried out on the analyzed section. Up to the early 1990s hardly any repairs were done either. Later on, the scope of maintenance was limited to making good the distressed concrete slabs, including transverse and longitudinal cracks. The condition of the motorway before the renewal project is shown in the picture below .The cause of cracks and other distress was the specific composition and the high volume of traffic of as much as 31,384 vehicles/day, as counted at the traffic count station No. 60713 during the survey in 2015. A point must be made that the volume of traffic has been increasing over many years. For example, in the period 2000–2015 it increased on the analyzed section by 140% . In 2015The assessment of the concrete pavement was related to the A6 renewal project with the planned full recycling of the pavement structure on the section under analysis.As part of this research, cores were cut from the existing concrete pavement in order to assess the main fatigue life parameters . In addi—Obtain a simplified petrographic description according to EN 932-3:1999/A1:2004 ,—Determine the compressive strength of concrete according to EN 12390-3:2019 , —Determine the density of concrete according to EN 12390-7:2011 ,—Determine the water absorption of concrete according to the Polish Standard No. PN-B-06250:1988 ,—Determine the F150 freeze-thaw resistance of concrete according to the Polish Standard No. PN-B-06250 [—Determine the porosity characteristics in hardened concrete according to EN 480-11:2008 ,—Determine the freeze-thaw resistance with de-icing salts according to EN 1340:2004/AC:2007 .As part of condition assessment of the concrete pavement the test specimens were prepared for tests carried out to:—Determination of resistance to fragmentation by the Los Angeles test method according to EN 1097-2:2010 ,—Determination of water absorption of analysed aggregates according to EN 1097-6:2013-11 ,—Determination of aggregate resistance to cycling action of freezing and thawing according to EN 1367-1:2007 [—Determination of California bearing ratio (CBR) according to 13286-47:2012 .Then, in order to assess the suitability of aggregate obtained from the concrete recycling, its physical and mechanical properties were determined by carrying out basic laboratory tests, which covered the following scope:In practice, the properties listed above decide on the acceptance or rejection of material for use in individual layers of the pavement structure and the reinforced (improved) soil.The article also presents the results of laboratory tests carried out by the GDDKiA’s road testing laboratory of Olsztyn  on the concrete cores cut from the pavement of the S22 expressway during the renewal of the section between the city of Elbląg, Poland and the state border of Poland. The method and the time of construction of this pavement were the same as of the pavement of the analyzed section of the A6 motorway. The compressive strength, freeze-thaw resistance and water absorption tests were carried out, plus determinations of tensile splitting strength according to EN 12390-6:2019 [Visual examinations of the cores cut from the A6 motorway showed that the concrete pavement of ca. 21 cm total thickness was placed in two lifts applied with the wet-on-wet method . The uppIn the core shown in the picture below  one can All the cores cut from the A6 pavement were conditioned in accordance with the standard procedure and polished when used for measurement of the mechanical properties.The main component of the upper layer mix was a crushed igneous rock, namely basalt  basalto.In the lower layer , the mai3 for the upper layer and 2404 kg/m3 for the lower layer. All the test results are compiled in The density of concrete was determined on the total number of six cores cut from the pavement, three from each of the two layers. The test procedure of EN 12390-7:2011  was usedThe compressive strength of concrete was determined on the total number of six cores, three from each of the two layers. The test procedure of EN 12390-3:2019  was usedThe strength of the upper layer concrete was higher than the strength of the lower layer concrete by ca. 28%). The strength test procedure according to EN 13791:2008 [%. The stReuse of Recycled Materials, it needs to be pointed out that in terms of the compressive strength the concrete obtained from recycling of the A6 motorway pavement satisfies the requirements specified for concrete that after crushing could be used for unbound sub-base and treated subgrade layers and also for road base layer construction, i.e., it can be rated in classes CC20 and CC30 respectively.Considering the recommendations  regardinAbsorption, defined as an increase of weight of concrete due to uptake of water, was determined according to the Polish Standard No. PN-B-06250:1988  on a totIt is worthwhile to note that the obtained absorption values are much lower than the limit of less than 5% as specified for concrete exposed to direct environmental actions according to PN-B-06250:1988 .g—for the upper layer and d—for the lower layer), which following the tests were subjected to 150 freeze-thaw cycles while the remaining samples were kept immersed in water. After 150 cycles the samples were subjected to visual examination. The samples showed neither surface distress nor cracking. Next, the samples were weighed and subjected to the compressive strength test. The test results are compiled below in EN 206:2014-04  does notFrom these results it transpires that after 150 freeze-thaw cycles at the test temperatures of −20 °C for freezing and +20 °C for thawing the tested concrete featured very good fatigue resistance, which allows us to conclude that the exposure to heavy traffic and de-icing salts used as winter maintenance agents (the motorway runs through an area with frequent daily freeze-thaw events) had not caused deterioration of the pavement. The average loss of weight in the tested samples was 0.15%. The decrease of compressive strength was less than 20%, viz. 16.2% for the upper layer concrete and 6.1% for the lower layer concrete. These values satisfy the freeze-thaw resistance requirement.Resistance to the action of de-icing products was determined with the method used for the rating of precast concrete units, such as curbs and pavers. The freeze-thaw resistance in the presence of de-icing salts was tested according to the procedure of EN 1340:2004/AC:2007  concrete2. The mean mass loss after 28 and 56 freeze-thaw cycles was below 1.0 kg/m2. The obtained values of freeze-thaw resistance in the presence of de-icing salts satisfy the requirements of FT2 freeze-thaw category, as defined in EN 13877-2:2013-08 [In each case the mass loss from a single sample was below 1.5 kg/m:2013-08 .The same kind of testing was simultaneously carried out at the GDDKiA’s road testing laboratory of Olsztyn for the concrete pavement of the Elbląg-Kaliningrad road constructed in 1938 using the cores obtained during renewal of the section between the city of Elbląg, Poland and the state border of Poland. The tests were carried out on nine 100 mm cores and three 150 mm cores. The test results are compiled in The compressive strength, absorption and freeze-thaw resistance data obtained for the concrete of the S22 pavement are very close to the values obtained for the A6 pavement. In addition, the tests carried out at the GDDKiA’s road testing laboratory of Olsztyn revealed a very tight structure of the tested concrete, as confirmed by low water penetration. The tensile splitting strength values satisfy the requirements of the assumed tensile splitting strength class SC 5.0 according to EN 13877-2:2013-08 .—A%,Total air content —α mm−1,Specific surface of the air void system —L mm,Spacing factor —300A%,Micro air void content (amount of air voids below 0.3 mm in size) —R%. Paste-air ratio The air void size distribution was determined according to EN 480-11:2008 . The anaA computer image analysis method was used to evaluate the microstructure of concretes and the parameters of pore structure were calculated; these parameters included relative volume fraction, relative specific surface area, and pore arrangement ratios . The samThe results of metallurgic examination of the four samples are presented in An image of sample 1.1 taken from the lower layer of pavement during examination is shown in The air void size distributions determined during examination of samples are presented in A ranged from 5.4% to 6.1%, the specific surface α ranged from 23.1 to 26.0 mm−1 and the paste/air ratio R ranged from 4.2 to 4.8. Most important for the freeze-thaw resistance evaluation are, however, the values of the spacing factor L and the micro-air content 300A, which were in the ranges of 0.17 to 0.20 mm and 1.51–1.86% respectively.The air void distribution parameters determined according to EN 480-11:2008  in the lThe concrete slabs of the A6 motorway pavement, which were planned to be recycled to provide reclaimed aggregate, featured very good physical and mechanical properties, as confirmed by the test results presented in 3.2 and 3.3 above. In the authors’ opinion, the above-described reclaimed material can, following appropriate processing, be used to substitute some of the new aggregate in concrete mixes for paving applications, even for the lower layers of pavement. Unfortunately, the Polish guidelines and specification do not provide for the use of aggregate reclaimed from concrete pavements for production of new PCC pavement mixes. Therefore, it was decided to use all the reclaimed material for construction of the road base layer, the foundation of the new pavement. The concrete pavement crushing process produced a 0/31.5 mm continuously graded material which, in relation to the on-going A6 renewal project, was subjected to the essential quality control tests at the GDDKiA’s road testing laboratory of Szczecin, Poland. The tested parameters included grain size distribution according to EN 933-1:2012  and CBR The grading curve of the 0/31.5 mm mixture containing reclaimed aggregate obtained from recycled pavement slabs of the A6 motorway fell within the grading envelope. The amount of particles smaller than 0.063 mm was 3% (m/m), which is less than the maximum allowed. The tested 0/31.5 mm mixture, compacted in a laboratory at optimum moisture content, featured a very high value of CBR (ca. 160%) . The req4 category, confirm the suitability of this material for the construction of the road base and sub-base layers and for subgrade treatment as well. A very good crushing value (LA35) of the reclaimed material is also worthwhile noting.The crushing value, absorption and freeze-thaw resistance of the reclaimed concrete aggregate were also determined . AccordiThe tests indicated very good physical and mechanical properties of the concrete under analysis. The strength properties satisfy at least the requirements for class C40/50 according to EN 206:2014-04  or CC40 The freeze-thaw resistance values after 150 cycles of alternate freezing and thawing testify to a very high quality and durability of the concrete in question. Furthermore, the experimentally determined freeze-thaw resistance in the presence of rock salt (NaCl) testify to its resistance also to the combined frost and de-icing salt exposure. The top layer concrete can be classified in the FT2 freeze-thaw resistance category. The air void analyses of the samples of the over 80-year-old concrete of the A6 motorway pavement showed that the concrete satisfies the contemporary requirements specified for PCC pavements, which confirms the long-lasting, perpetual character of pavements of this kind. The reclaimed aggregate obtained from crushing the entire pavement of the A6 motorway satisfies the requirements of  code of (1)The test of compressive strength was 65.8 MPa for the upper layer and 51.2 MPa for the lower layer. With the compressive strength value in excess of 50 MPa, the tested concrete can be rated as at least CC40.(2)The freeze-thaw resistance values after 150 cycles of alternate freezing and thawing testify to a very high quality and durability of the concrete in question.(3)300), the spacing factor, in turn, was below 0.200 mm (L = 0.185 mm). The air void analyses of the samples of the over 80-year-old concrete of the A6 motorway pavement showed that the concrete satisfies the contemporary requirements specified for PCC pavements, which confirms the long-lasting, perpetual character of pavements of this kind.The air void analysis showed that the analyzed concrete contained 1.6% of micropores, i.e., air voids smaller than 300 μm (A(4)The example of the A6 motorway renewal project served to demonstrate that reclaimed concrete aggregate, obtained by crushing the entire pavement, can be used for production of the new pavement courses.The following conclusions can be drawn on the basis of the authors’ testing and analyses of the test data:Furthermore, the results of the tests carried out at the GDDKiA’s laboratory of Szczecin as part of the on-going quality control in relation to the A6 renewal project confirm satisfaction of the grading and CBR value requirements.