Superior mesenteric artery aneurysms (SMAAs) are rare and potentially life-threatening. Whether surgical or endovascular repair is performed, mesenteric ischemic complication is the greatest concern. A 56-year-old gentleman with SMAA underwent surgical resection with reconstruction of the superior mesenteric artery (SMA) and its branches using the great saphenous vein with several techniques, including island reconstruction of the branches, staged segmental cross-clamping, and an external shunt, to reduce the mesenteric ischemia time. The postoperative course was uneventful with no signs of mesenteric ischemia. A computed tomography scan showed that all grafts to the SMA and its branches were patent. SMAAs are often symptomatic with abdominal pain; however, due to the increased use of modern imaging techniques, such as computed tomography (CT) scan and magnetic resonance imaging, more asymptomatic SMAAs have been incidentally detected. Whether symptomatic or asymptomatic, SMAAs are potentially life-threatening with a risk of rupture and embolism. Rupture of SMAA causes critical intraperitoneal hemorrhage; according to a recent study, the rupture rate at presentation was 38%. Embolism can also lead to a lethal condition due to mesenteric infarction. Therapeutic strategies for SMAAs include surgical or endovascular interventions; however, the optimal treatment is unknown because of their rarity. The complication of mesenteric ischemia leading to mesenteric or pancreatic infarction is the most critical concern. Therefore, careful monitoring for mesenteric ischemia is required when performing either surgical or endovascular interventions for the superior mesenteric artery (SMA) and its branches. Herein, we present a case of successful surgical resection of SMAA with reconstruction of the SMA and its branches using the great saphenous vein (GSV) with several techniques such as island reconstruction with a double-barrel graft, staged segmental cross-clamping, and an external shunt, to reduce the mesenteric ischemia time.Superior mesenteric artery aneurysms (SMAAs) are rare entities, accounting for 6.7%–6.9% of all visceral artery aneurysms (VAAs).The patient was a 56-year-old male with a history of hypertension and dyslipidemia, in whom a CT scan performed 9 years earlier as part of a medical checkup had detected a 15-mm-diameter SMAA. He was referred to our institution, where it was found that the aneurysm had grown to 25 mm in diameter.The SMAA was located 20 mm distal to the origin of the SMA and was dissected with a patent false lumen. The aneurysm and dissection longitudinally extended 3 cm distal to the origin of the aneurysm. The true lumen of the aneurysm gave rise to the middle colic artery, three jejunal arteries (JAs), and right colic artery (RCA) from the proximal end. The ileocolic artery (ICA) originated from the SMA immediately distal to the end of the SMAA  with placement of a low-profile stent graft (SG) was considered to be too difficult owing to the short distal landing zone and the risk of embolism due to the intra-aneurysmal thrombus. The coverage of the branch arteries was also a concern with EVT. Therefore, we decided to perform surgical resection.The operative technique used was as follows:We performed preoperative ultrasound evaluation to mark the GSV and its branches at the left groin and then harvested the GSV, preserving one major branch near the saphenofemoral junction.The proximal and distal aneurysm necks were dissected and encircled through a median laparotomy. The three JAs, RCA, and ICA were also dissected.After systemic heparinization, the distal portion of the SMAA was clamped while maintaining antegrade blood flow to the JAs, and an end-to-end anastomosis was fashioned between the distal end of the SMA and the GSV. A vessel cannula was introduced into the branch of the GSV and connected to a 4-Fr arterial sheath inserted into the right femoral artery to initiate distal perfusion to the SMA and ICA via the distal anastomosis. The external shunt flow was 40 ml/min. The ischemia time for the SMA and ICA was 10 min  and GSV (4 mm); therefore, another GSV was anastomosed in a side-to-side fashion, and a double-barrel graft of the GSV was prepared, which was anastomosed to the proximal end of the SMA. The SMA and ICA were antegradely perfused from the right leg, and the external shunt was completed  and anastomosed to the left leg of the double-barrel graft in a side-to-end fashion. The ischemia time for the JAs was 32 min . The GSV is the most widely used graft material in bypass grafting surgery because surgeons can harvest a long graft and form a conduit as required for grafting with venovenostomy. We created a double-barrel graft by performing venovenostomy with a side-to-side anastomosis between two lengths of the GSV, which enabled us to address the caliber discrepancy and maintain perfusion to the SMA and ICA during reconstruction of the JAs. The limitation of this technique is that the durability of a double-barrel graft is unknown.Conventionally, SMAAs have been treated by a surgical approach. Surgical techniques include simple ligation, aneurysmorrhaphy, and resection of the aneurysm with or without revascularization. In the surgical treatment of SMAA, ischemic complications are a concern. Stone et al. reported that simple ligation could be performed safely without mesenteric ischemia.; this implies that some patients may require revascularization of the branches as well as the trunk of the SMA. Preoperative and intraoperative evaluation of mesenteric perfusion is important. There is also the question of which branches should be revascularized, particularly in a patient with a large SMAA involving several branches. The island technique was useful for reducing the mesenteric ischemia time when multiple branches were simultaneously reconstructed. Rigorous evaluation of anatomy by preoperative CT angiography was helpful for planning the graft design.There is controversy over whether or not the branches of the SMA should be revascularized, with few reports mentioning branch reconstruction. However, Jiang et al. reported on a patient who underwent bypass only to the trunk of the SMA and developed an infarction in the small intestine A combination of these techniques reduced the mesenteric ischemia time, resulting in an uneventful postoperative course.In addition to island reconstruction, we performed several techniques to reduce the mesenteric ischemia time. One was the staged segmental cross-clamp technique, which is used to maintain perfusion distal to the clamp site when repairing a thoracoabdominal aortic aneurysm. The other technique used was an external shunt from the femoral artery to the SMA and ICA via a branch of the GSV, which is used in coronary artery bypass grafting to maintain distal perfusion. The advantage of SG placement is its ability to exclude aneurysms while preserving blood flow in the affected vessels, thereby avoiding the risk of distal ischemic complications. However, the issue with SG placement is the coverage of major branches, which arise from aneurysms and landing zones; sacrifice of these branches can lead to mesenteric ischemia and significant morbidity if collateral circulation is insufficient. Stent thrombosis is the most critical complication after SG placement, which may cause mesenteric infarction. Some reports have described stent thrombosis that led to bowel necrosis after SG placement to the SMA. Our patient had a short distal landing zone and many branches involved in the aneurysm, which would be sacrificed by SG placement. For these anatomical reasons, we elected to perform open repair.Currently, EVT for SMAA is a valid therapeutic alternative with a high success rate and low procedural morbidity and mortality. EVT can be performed with placement of an SG and/or embolization with coils, glue, or plugs. Anatomical indications for SG placement include the presence of adequate proximal and distal landing zones without excessive tortuosity.We have reported a case of successful surgical resection of a SMAA with reconstruction of the SMA and its branches using the GSV. A combination of several techniques, including island reconstruction with a double-barrel graft, staged segmental cross-clamping, and an external shunt, reduced the mesenteric ischemia time and led to an uneventful postoperative course without any complications of mesenteric ischemia.


Animals can play an important role in preparing tissues for human through the development of xenotransplantation protocols. The most common problem with liver transplantation like any other organ transplantation is organ supply shortage.To evaluate the in utero xenotransplantation of mouse bone marrow-derived stromal/stem cells (BMSCs) to the liver of rat fetus to produce mouse liver tissue.BMSCs were isolated and confirmed from enhanced green fluorescent protein (eGFP)-genetic labeled mice. Using a microinjection protocol, mice BMSCs were injected into the liver of rat fetuses in utero on day 14 of pregnancy. After birth, livers were collected and the presence of mice eGFP-positive cells in rat livers was evaluated through polymerase chain reaction.The eGFP mRNA was detected in the liver of injected infant rats. BMSCs of adult mice were capable to remain functional probably as hepatocyte-like cells in liver of infant rats after in utero xenotransplantation. BMSCs have the potential for intrauterine xenotransplantation for the treatment of liver dysfunction before birth. This method can also be used for xenoproduction of liver tissue for transplantation. Stromal/stem cells (SCs) are known as undifferentiated cells, with the ability to either divide into identical daughter cells  or to differentiate into specialized somatic cells  (1). These cells were identified and isolated from different type of tissues (2-7). The SCs in bone marrow stroma comprise a restricted area; however, it can be easily proliferated. These cells can be used for the treatment of non-hematopoietic diseases (8-10).Liver cirrhosis indicated via regenerative nodules' formation and hepatic architecture impairment is a late phase of progressive hepatic fibrosis (11). It is generally irreversible in its advanced stages. Liver transplantation has long been the unique curative treatment for acute or chronic liver diseases (12). It involves several essential issues like surgical difficulties, lack of donors, rejection, and high value of expenses.Owing to the many advances in prenatal diagnosis and microsurgery techniques, intervention at fetal period has become one of the most advanced techniques to treat or prevent many deadly diseases that begin or are diagnosed at the early stages of embryologic development (13). Prenatal treatment can prevent from many after-birth complications due to the fact that some genetic diseases may damage organs in utero irreparably (14). Therefore, stem cell transplantation in a living organism is considered as an important clinical measure in managing the patients with congenital, anemia, metabolic, and immune system abnormalities (15). Xenotransplantation means producing an organ from one species in other species using transplantation method. Studies have been performed on in utero injection of human or animal stem cells using sheep and pigs as the host and the cells have been injected into the cavity of peritoneum, heart or liver of the fetuses (16). The ease of separation and proliferation of mice bone marrow-derived stromal/stem cells (BMSCs) made it a good choice for our study to inject into fetus of rat before formation of fetal immune system.GFP gene in rat pup's liver.Considering the time of immune system formation in the fetus, Table I displays different mammals that can be used for in utero xenotransplantation. In the early stages of pregnancy, since the fetal immune system is not complete, it cannot recognize foreign tissues, and therefore the xenotransplanted cells are not rejected. In the present investigation, we decided to examine intrauterine injection of BMSCs in mice with enhanced green fluorescent protein (eGFP) into the rat fetal liver and also investigate the presence of For this experimental study, Three adult female  and penicillin-streptomycin antibiotics . Under the class II cell culture hood, both ends of the bones were cut using scissors, and the bone marrow canal was flushed using a needle connected to a syringe containing Dulbecco's Modified Eagle's medium . The cell suspension was collected in a Falcon tube and was then centrifuged at 1200 rpm for 5 min. After removing the supernatant, 1 mL cell culture medium was added to the sediment and cells were re-suspended by pipetting. Complete culture medium contained 90% DMEM , 10% bovine calf serum , 1% penicillin-streptomycin antibiotic (Sigma), 1% antifungal solution , and 1% non-essential amino acid . The cell mixture was transferred to a 25T flask containing 4 mL of complete culture medium and incubated in 5% CORefreshing the medium every three days about two wk, the bottom of culture flask was filled by cells. To avoid medium changing stress on the proliferation and cell growth, 1 mL of the previous medium was mixed with fresh medium during medium refreshment. Before 90% confluence of the cells, they were passaged. After, removing the culture medium and washing with PBS, the cells were trypsinized  and incubated for 3-4 min to detach from the bottom of culture flask. Culture medium was added to the plate twice as much of trypsin added in the previous step to stop the enzyme activity. The cell suspension was collected in a Falcon tube and centrifuged at 1200 rpm for 10 min at room temperature. After pouring out the supernatant, 3 ml of the culture medium was added to the cell sediment and cells were re-suspended. In the next step, every 1 ml of this solution was added into 75T culture flasks that were already filled by 14 ml culture medium and were incubated. This process continued until cells reached to the third passage.When SCs filled a T75 flask at the third passage, their culture medium was removed. Next, they were washed with 3 ml of PBS. After that, the cells were treated with 3 ml trypsin / EDTA for 3-4 min and after adding 6 ml of culture medium, centrifuged at 1200 rpm for 5 min. The resulting cell sediment was used for RT-PCR reaction. First, the entire contents of the RNA  were extracted using the extraction column kit  according to the manufacturer's instructions. To ensure the quality of the extracted RNA, 5 ml of that was monitored over agarose gel electrophoresis as well as its absorption at a wavelength of 260 nm was evaluated.The resulting RNA was kept in the freezer at -70°C until usage time. Next, the synthesis of complementary DNA (cDNA) was done using a kit . According to the concentration of RNA, a decent amount of RNA was utilized in micro tubes, containing all the components needed to carry out the desired reaction. Then with the help of DEPC water, the reaction volume was adjusted to 20 ml. Reaction was carried out in a schedule with respect to time and temperature. The resultant product was kept in the freezer (at -20°C) until used. In the next step, polymerase chain reaction (PCR) was performed using specific primers (Table II). Mentioned reaction was done using master mix manufactured by Amplicon Company, so the necessary amount of cDNA (directed by the kit manufacturer) was added to micro tubes and placed in temperature and time process as follows. After the completion of the reaction in Veriti 96 well Thermal cycler , the presence of specific PCR products in desired size was assessed in 1.5% agarose gel under gel documentation system  with the aid of DNA Safe Stain.The vaginal smears was used to detect the stage of estrous cycle of female rats using microscopic observation (30). The female rats at proestrus or estrous stages were transferred to cage of a mature male rat and left overnight for mating. Thereafter, their early pregnancy was confirmed using the vaginal smear method (31). In detail, the presence of vaginal plug in the female rats were examined in the next morning. They were separated from the males. Cellular characteristics of vaginal smears were evaluated once again on days four and five post-coitus using light microscopic. A presence of cellular characteristics of diestrus or metestrus on days four and five post-coitus were the signs of a positive indication for pregnancy.In order to make a simple, inexpensive, and relatively flawless DIY (Do-It-Yourself) needle for microinjection of cells in fetus, the following steps were performed.A simple needle-puller was made manually. To do that, we found a torch lighter with a very sharp and focused flame . We also used simple glass micro-hematocrit capillary tubes instead of sophisticated state-of-the-art capillary tubes . To pull the capillary on the flame, we found a steady table to place the torch lighter on and kept the hands in a comfortable position. The two ends of the tube were kept by thumbs and index fingers in a way that they could be easily rolled between them. Then, the middle of the capillary was kept at the apex of the flame while rotating the capillary. As soon as the middle part of the capillary was soft, the tube was gently taken away from the flame and pulled horizontally as steady, fast, and far as it could be, before it hardened. Subsequently, the fine and filamentous glass that was keeping the two needles attached was broken . Then, the two very sharp needles were beveled and forged. However, they can be used without any further modification; beveling and forging the needles can improve the results. Note that one needs to master the skill of pulling needles by hand through practice.The micromanipulator mechanism relies upon one important concept: a device that helps you move the tip of the needle, for instance, in a three-dimensional coordinate system with very high precision and preferably high accuracy. We could not afford a state-of-the-art and sophisticated micromanipulator. Thus, we made one for ourselves, putting to use a light microscope stage, two 20 cm-long metal rods, a metal protractor, and a retractable antenna . Using a microscope stage, we were able to have enough precision for our work. We fixed one end of a metal rod on the microscope stage . Next, we fixed the other end of this rod to one end of the other rod. Then, we attached the second rod and a protractor on its 90° line. Next, we attached the retractable antenna on the rotating guide of the protractor. The antenna works as the holder and the needle was installed on its tip. We made a simple and cheap needle beveller in our laboratory as well. First to make sure that glass dust does not clog our needle, we attached it to flexible tubing and a syringe full of deionized water . Then an extra-fine abrasive disc was glued on a small 9 volt DC fan (a computer fan) and the fan was plugged to a power supply . Then, the needle's tip was put upon the abrasive with a 30° slope . As the needle was gently forced toward the abrasive, we pushed the water through the needle to drive the glass dust away.Moreover, we built a simple micro-forge. A short and fine nichrome  heating filament was plugged into a 12-volt power supply . Placing the filament under a stereomicroscope, we were able to sharpen the needles even further. We gently and steadily attached the very tip of our needles on the heated filament. After the tip of the beveled needle stuck to the filament, the power supply was turned off, and before the glass got hard again, it was pulled and sharpened . The prepared microinjection needles were transferred to a box and sterilized in an autoclave machine.In order to inject BMSCs into pregnant rat fetal liver, the required amount of BMSCs from bone marrow labeled with eGFP was produced in the third passage. Then, 4 ml of medium culture was added to cells sediment and cells were suspended; 1 ml of this cells mixture was pulled into an insulin syringe, and thus, required cells were prepared for injection into the rat fetal liver. Before injection, a pulled needle was attached into a plastic tube of a 23-gauge butterfly needle after removing the needle part. Then the tube was attached to the filled syringe and cell suspension was gently pushed into the microinjection glass needle.This study was conducted on three pregnant rats at day 14 of gestational age that was determined through their vaginal plug (length of pregnancy in rats is approximately 21 days). These animals were provided from the Comparative and Experimental Medicine Center of Shiraz University of Medical Sciences, Shiraz, Iran. Pregnant rats were anesthetized with ketamine and xylazine. Animals were placed in the supine position and lower abdomen was shaved and then disinfected. Following this procedure, an incision was carried out in the lower abdomen vertically; after opening the fascia, subcutaneous layer, and muscles of that area, the uterus was removed from the abdomen and the position of embryos were checked. By applying pressure to the syringe, the cell suspension was gently forced into the pipette. A glass needle was entered into the amniotic fluid and then into the fetus in the area of the liver that was observed with microscope through the wall of uterus where each of the embryos were located. The injection of stem cells was carried out with 5 eGFP gene in the resulting sample was evaluated through the PCR .Two wk after the delivery, the newborn's liver as treated samples, mother's liver as negative control (and to ensure that there is no cellular migration), and mice liver as a positive control were removed. The sampling was done on livers and DNA was extracted using the tissue DNA extraction kit. Polymerase chain reaction . Next, using specific primers (Table II), the presence of The present experimental study was approved by the Shiraz University of Medical Sciences Ethics Committee (project number: 92-01-01-7021).An important feature of mice used in this study was that they were transgenic so that due to the eGFP expressing gene insertion in their genetic material, most of the cells derived from these animals have been labeled and thus can easily be tracked, genetically. Inverted light microscope was used to image the isolated SCs . The same field was also imaged by epi-fluorescent microscope with filter G  that confirmed the expression of eGFP and filters B and R of the same field with now fluorescent signal to confirm the eGFP signal is not an autofluorescence signal . In the early days of the primary culture, the population of BMSCs with spindle or fibroblast-like fetures had the highest number among others. Although rounded or flat cells were visible, too. Over time, the whole of culture medium was full of cells after about two wk. When the culture medium was filled with BMSCs, the cells were passaged; therefore, as a result of the treatment with trypsin/EDTA, the cells were separated from bottom of the culture plate and transferred to three T75 flasks. The rate of cell proliferation and growth were increased from passage one to next passages. Cultivation surface was filled out in about three to four days. The cells are often seen in the form of spindle or fibroblast-like fitures . This process was continued until the third passage.In order to ensure the identity of the cells in the third passage, the presence of specific marker for SCs and the absence of specific markers of hematopoietic stem cells were evaluated. In this regard, the presence of CD90 mRNA (Thy-1 cell surface antigen) and the absence of specific mRNAs of CD34 (hematopoietic progenitor cell antigen) and CD45 (protein tyrosine phosphatase) were assessed .eGFP gene , the same process was performed on the liver of neonatal rats, and the presence of mice eGFP mRNA in the liver of in utero xenotransplanted rats were confirmed . The same procedure was performed on the mother rat liver that confirmed the absence of the eGFP gene .By ensuring the proper functioning of primers of the In the present study, the possibility of the presence and viability of mouse SCs in rats' infants after in utero transplant to fetal liver was measured. BMSCs obtained from mouse were prepared at the third passage. BMSCs are attractive alternative of successful stem cells-based treatments due to its availability, easy extraction method, and its rapid proliferation (32). In addition to the ability to differentiate into hepatic category (33), the SCs produce different cytokines and signaling molecules which can cause various effects in hepatic injury position such as immune response regulation, anti-inflammatory effects, anti-apoptotic and cell proliferation stimulation (34).Intrauterine stem cell transplantation is considered as a medical procedure to treat a number of disorders and diseases and enjoys numerous advantages compared to postnatal treatment. For example, there is the ability to prevent progressive and irreversible damage to the fetus during the development (35). The foundation of stem cell transplantation to embryo is based on two assumptions: immature fetal immune system cells are not at a level of maturity in which it can distinguish between foreign and their own cells and therefore are not able to stimulate the appropriate immune response against the foreign cells. This eliminates the need of matching between donor and recipient MHC molecules. The high proliferative potential of the fetus environment in early pregnancy and normal migration of stem cells to different parts of body is the other benefit of this approach. Also, proliferating fetus is relatively empty of the presence of hematopoietic environment that, in turn, allows the establishment and transplantation of donor cells in large amounts, without having to discharge the host storage of hematopoietic (36).However, further studies need to be done to understand the recruitment molecular mechanisms and deployment of SCs, growth, and proliferation in normal conditions of body or the ability to differentiate them into different cell lines in special environmental and developmental conditions. Also, it is necessary to identify the growth factors and effective chemokines involved in compliance and eventual transplantation of these cells in target tissues before applying at clinical level. Many factors, such as toxins, viral infections, immune system defects, and genetic disorders can lead to liver dysfunction and chronic or acute liver disease. In this situation, liver dysfunction can lead to conditions in which even the patient life is at risk. However, one unique characteristic of the liver is its ability to regenerate itself after injury. In response to simple liver damages like removing some part of liver tissue or after acute damages, restoration are carried out by proliferation of internal hepatocytes and without the need for auxiliary restorative processes. In chronic injuries in which the proliferation capacity of mature hepatocytes is inhibited, small, oval-shaped cells that express stem cell marker and biliary class cells marker, appear in the area surrounding liver tissue (37). It seems that these oval cells and precursor-like cells contribute to liver reconstruction by differentiating into hepatocytes (38).In case of persistent injury, chronic disease and intensified liver fibrosis, the only effective treatment would be liver transplant method. However, the major limitation of this method is that usually there are not enough livers for transplantation. Also, side effects such as the lack of immunological compatibility and transplant rejection, irreversible complications associated with long-term use of medications that suppress the immune system, and the high cost of transplant surgery makes this method undesirable for many patients (39). However, on the other hand, the shortage of suitable organ for transplant will also lead to the death of many patients in transplant waiting list. It is therefore essential that new liver reconstruction methods be developed and the need for transplantation of some or all of liver tissue be met.Despite the widespread use of BMSCs in clinical and pre-clinical trials of chronic liver disease, several subjects including the ability of differentiation and proliferation, the possibility of producing fibrous tissue, the best injection method, the best time stage of treatment, the most appropriate cell number, and frequency of injection should be considered. Therefore, the eGFP-genetically labeled BMSCs of adult mice were capable to remain functional probably as hepatocyte-like cells in the liver of infant rats after an in utero xenotransplantation. The therapeutic value of BMSCs lies in regulating the immune system and releasing the nutritious factors such as growth factors and cytokines.The authors declare that there is no conflict of interests.


Semi-Dense Asphalt (SDA) mixtures are nowadays recommended for the surface layer of low noise roads in urban areas due to their optimal functional characteristics. Moreover, the use of polymer-modified bitumen (PmB) in its design results in high mechanical performance. However, this type of highly modified bitumen implies significant economic and environmental disadvantages. The polymer modification increases the production cost, involves higher mixing temperatures, and makes the recycling process of the asphalt mixtures challenging. As a potential alternative to PmB in SDA mixtures, this experimental work analyses the dry process for the incorporation of crumb rubber (CR) from waste tires. Particularly, the main objective was to study the aging effect and the recyclability of asphalt mixtures prepared in the laboratory with two different types of CR. The volumetric properties and mechanical performance of the mixtures artificially aged and rejuvenated were evaluated. The results obtained show that mixtures with CR have adequate performance, being less susceptible to aging than a conventional polymer-modified mixture. Furthermore, the rheological response of asphalt binder samples recovered from the mixtures at different aging states was analyzed. It was observed that the effect of the rejuvenator depended on the CR type, but this fact did not negatively influence the performance of the recycled mixtures. The road network plays a very important role in the transport of people and goods as roads are the most widely used mode of transport. Recent statistics on freight and passenger transport show that more than 70% of goods and 80% of passengers travel by road. More than 90% of the European road network is surfaced with asphalt, providing road users a consistent, safe, and durable surface for their journeys, whether local or across the entire continent .In recent years, new designs of asphalt mixtures have allowed the road surface quality to be improved. As an example, Semi-Dense Asphalt (SDA) mixtures combine high mechanical performance with other functional characteristics, such as the reduction of the noise from the tire/pavement interaction, making SDA especially interesting for urban areas . Due to The use of rubber from waste tires as elastic additive in asphalt mixtures has become a realistic alternative to asphalt mixtures with PmB for high performance roads. In addition, this implies significant environmental benefits. Along with the direct reduction of end of life tires, the feasibility of the rubberized asphalt for production processes with low energy consumption, as well as the decrease of emissions (CO and methane) for conventional hot asphalt production processes, have been reported lately ,7,8. FurIn order to obtain a suitable rubber for asphalt mixture production, waste tires must be followed a recovery process called “granulate recovery”. In this process, the waste tires are first cut into small pieces and the fabrics, as well as metallic components, are removed. Then, the size of the rubber is further reduced, resulting in Crumb Rubber (CR). Ambient grinding, cryogenic grinding, wet-grinding, and hydro jet size reduction are some of the technologies most commonly used. The final size and shape of the resultant CR particles will vary depending on the process employed ,10.The technique that incorporates the CR into the asphalt mixtures as part of the aggregates is commonly known as the dry process . During In the last few decades, the methodology that guarantees a better performance of CR modified mixtures has been developed . Along wAs a direct consequence of the technology progress, the use of the dry process to produce CR-modified asphalt mixtures has now reached the potential to be used with confidence in practice. However, unknown details, such as the long-term performance or the recyclability of this kind of asphalt mixtures, must be carefully analyzed. First studies on CR-modified binders reported that they exhibit improved aging resistance in comparison with their corresponding base binder ,27,28,29The aim of this work was to further the knowledge of the asphalt mixtures modified with CR using the dry process. In particular, the main objective of this study was to assess their aging susceptibility and recyclability. To achieve this goal, a set of SDA mixtures were prepared at laboratory scale by the dry process incorporating two different types of CR. The mechanical performance of these mixtures was evaluated at three aging states, comparing the results with a reference mixture with PmB. This work intends to demonstrate that the addition of CR does not compromise the reuse of the mixture and is comparable to a conventional reclaimed asphalt pavement (RAP) at the end of its service life. To do this, laboratory-prepared RAP was obtained by artificially aging the asphalt mixtures. Then, the aged mixtures, as well as 100% RAP mixtures with rejuvenator, were evaluated, analyzing the differences between the reference PmB mixture and the experimental ones with CR.In this section, details of the materials and the experimental methods used in the different stages of the study are further described. A scheme with the methodology followed in this study for the analysis of the effect of aging and potential recyclability of asphalt mixtures with CR prepared by the dry process is summarized in Three SDA mixtures with a nominal maximum particle size of 4 mm have been produced: two experimental mixtures modified with two different types of CR using the dry method and a reference mixture. All the mixtures were designed using the same conventional aggregates, resulting in the particle size distribution plotted in Likewise, specific details of the asphalt mixtures studied are summarized in The only difference between the two experimental mixtures is the type of CR used. The first type of CR (henceforth CR-A) was produced by ambient grinding method and, later, enhanced with a surface treatment using polymers. The second type of CR (henceforth CR-B) was also produced using the ambient grinding, but, in this case, no surface treatment was applied. Both CR types had a maximum particle size of 800 μm. Environmental Scanning Electron Microscope (ESEM) micrographs of each type of particles are shown in During the mixing process, the dry method was used to prepare the experimental mixtures. The CR  was directly incorporated into the mixture as additive with no adjustment of the gradation curve or aggregate replacement. First, the preheated aggregates (185 °C) were mixed with the CR (room temperature) for 1.5 min. Then, the preheated binder (160 °C) was added and mixed with the aggregates and CR for another 2 min. The loose mixture was then placed in the oven at 165 °C for 120 min (conditioning time) . AfterwaTo simulate the aging effect, an accelerated aging process was carried out in the laboratory. For the CR modified mixtures, the conditioning time was considered enough to simulate short-term aging . Likewise, the reference mixture was subjected to the same process  in order to isolate the influence of the CR of the experimental mixtures during the analysis of the results. Furthermore, to simulate long-term aging (associated with road service life) the Strategic Highway Research Program (SHRP) Long-Term Oven Aging (LTOA) method was applied. This method consists of keeping the compacted specimens in the oven at 85 °C for five days. According to different studies, the application of this method simulates a service life of 7 years for a dry-freeze climate and 15 years for a wet-no-freeze climate .TM RP1000  was used as rejuvenating agent in the preparation of a new set of asphalt mixtures. The rejuvenator content was fixed at 5.0% by weight of aged binder. This content was selected in accordance with the experience in previous research works [Once tested, and in order to evaluate their recyclability potential, the aged mixtures were considered as artificial RAP. Therefore, 100% RAP mixtures were prepared by using exclusively the artificially aged mixtures. Additionally, commercial Sylvaroadch works . It is iDetermination of the volumetric properties of asphalt mixtures: Bulk and maximum densities of several samples were experimentally obtained according to the standards EN 12697-6 (Saturated Surface Dry procedure) and EN 12697-5, respectively. As required, three specimens prepared by impact compactor (50 blows per face) were measured for the original and recycled mixtures. Afterwards, the air void content was calculated for each specimen as the ratio between the bulk and maximum densities as specified in the standard EN 12697-8.Marshall test (EN 12697-34): From each mixture and aging state, three different specimens were prepared by impact compactor (50 blows per face). Before testing, the specimens were conditioned in water at 60 °C for 45 min. Thereafter, a load at a constant speed of 50 mm/min was applied to each specimen until failure, recording the deformation obtained throughout the test. This data allowed calculating the corresponding test parameters: stability, flow, and quotient.Water sensitivity (EN 12697-12): The Indirect Tensile Strength Ratio (ITSR) is a parameter commonly used to quantify the moisture susceptibility of asphalt mixture. It is defined as the ratio of the Indirect Tensile Strength (ITS) of a water conditioned specimen (wet) and an unconditioned one (dry). In this study, for each asphalt mixture and aging state, a total of six specimens were prepared by impact compactor (35 blows per face) according the specification. The wet samples were conditioned at 40 °C for 72 h. Once conditioned, they were brought to the test temperature (22 °C) in a climate chamber and tested according to EN 12697-23 in order to obtain the corresponding values of ITS.In order to assess the performance of the different asphalt mixtures, a developed experimental protocol  was seleIn addition, asphalt binder samples were recovered from the experimental mixtures at the different aging states in order to analyze the combined effect of CR and rejuvenator on their rheological properties. The asphalt binder was extracted with solvent and recovered by rotatory evaporator (EN 12697-3). Then, the recovered samples were evaluated by means of rheological tests. In particular, complex modulus and phase angle for different test temperatures and frequencies (master curve) were determined . This teThe volumetric properties of the original and recycled mixtures after the aging processes and addition of the rejuvenator are summarized in As it can be seen from the results, the type of CR influences the volumetric properties of the asphalt mixture. Comparing to the reference mixture, the CR-modified mixtures show lower air void content, especially the mixture with CR-A. This is expected as the mixture design (gradation curve and/or binder content) was not adjusted to account for the addition of the CR and the consequent swelling process . The addConcerning the different CR modified mixtures, it was found that the mixture with CR-A shows lower air void content than the mixture with CR-B. Here, the effect of the type of CR can be better observed. As both CR types were produced using the ambient grinding method, they presented a similar shape and size of particles . NeverthMarshall Quotient (MQ), the ratio of stability to flow, is recognized as an indicator of the resistance of the material to shear stress and is also related to the mixture’s resistance to permanent deformation. High MQ values are associated to high stiffness and better resistance to creep deformation of the asphalt mixture .Comparing to the original mixtures, the experimental CR modified mixtures obtained lower flow values than the ones from reference mixture, finally resulting in higher MQ values. Therefore, these results at high test temperature (60 °C) seem to indicate that CR-modified mixtures are stiffer than the conventional polymer modified asphalt mixture. After aging, the reference mixture reduces its flow and increases its stability, resulting in a higher MQ value. As expected, the mixture is stiffer due to the effect of aging. However, both stability and flow for the CR-modified mixtures increase due to aging, resulting in similar MQ values or even lower in the case of the mixture modified with CR-B. These values reveal a lower aging susceptibility of CR-modified mixtures in comparison with a conventional SDA mixture. This behavior has been previously related to the effect of certain antioxidant compounds used in the tire fabrication process . HoweverComparing the original, aged, and recycled mixtures, it is difficult to draw any conclusions because there are significant differences in air void content. Volumetric properties have a significant influence on the performance of asphalt mixtures. This influence is clearly shown in the MQ values. All the mixtures after recycling process show an MQ value similar to the one obtained for their corresponding aged mixture. In this sense, less air void content leads to stiffer asphalt mixtures ,39, and The water sensitivity test results for the original, aged (LTOA), and recycled mixtures are shown in Analyzing first the overall performance obtained in the original state of the mixtures, the CR-modified mixtures resulted in ITSR values slightly lower to those of the control mixture. In this sense, further work would be required to optimize the CR-modified mixtures in order to meet the requirement established by the Swiss standard (ITSR > 70%). These results could be improved by modifying the mixture recipe or using specific additives to improve the adhesion between binder and aggregates. In terms of ITS, Mix B resulted in higher ITS values than reference and Mix A, indicating higher mixture cohesion .The aging effect can be analyzed by looking at the evolution of the ITS values. After long-term aging, the ITS values increased for all the mixtures. However, this was more significant for the reference mixture, as well as for the Mix A, whereas the Mix B kept its performance and showed only a small change in the strength of the material. These results follow the same trend as the Marshall test results for Mix B, as this mixture showed lower susceptibility to aging than the reference mixture. However, Mix A seems to present a higher susceptibility to aging in this test than in the Marshall test. The effect of aging on ITSR values was similar for all mixtures, increasing this value by around 7% after long-term aging.As far as recycled mixtures are concerned, all of them showed an adequate performance in this test. The mixtures modified with CR resulted in a slightly higher ITSR value than the reference mixture. In any case, all the mixtures resulted in a good ITSR value and met the requirement established in the standard. As indicated before, these results are only indicative, and it is not possible to directly compare the results obtained in the different aging states  due to the differences in the air void content of the mixtures.The complex shear modulus (G*) master curves of the extracted binders from the original, aged, and recycled mixtures are shown in Regarding the original mixtures, at low frequencies (higher temperatures), the polymer modified binder (PmB 45/80–65) used in the reference mixtures is stiffer than the binder samples obtained from the mixtures modified with CR using the dry method. This fact, partially related to the base binder used, could potentially cause some issues for the CR modified mixtures at high temperature. At high frequencies (low temperatures), all binders show similar values of complex shear modulus. Comparison between experimental mixtures shows how the use of untreated CR-B resulted in a higher complex shear modulus of the extracted binder than the use of CR-A, which was originally polymer coated.As previously discussed, the results obtained from the Marshall tests indicated that the experimental mixtures were stiffer than the reference mixture. The ITS results for the original state indicated that the strength of the experimental mixtures was lower than the reference with CR-B being closer to the reference. The master curves of the recovered binders corroborate the trend seen in the ITS. In any case, it is essential to consider the influence of the CR particles as elastic aggregate on the performance of the mixtures  and the In order to better analyze the difference found in the binders after the long-term aging processes and the effect of the rejuvenating agent on the recyclability for each mixture, the results for the recovered binder samples in the three different conditions are now compared together in These results indicate that for, all the mixtures, the complex modulus values were increased after long-term aging, especially at low reduced frequencies. The binder recovered from Mix A was found more influenced by the aging process, showing the higher rise in the complex modulus values. Contrary to the Marshall test, where experimental mixtures varied slightly in their results after long-term aging, these results indicate a significant influence of aging on the properties of the recovered binder. This difference highlights that the rheological performances reflect the visco-elastic behavior of binders only. Thus, they are only an indication of possible performance base properties of mixture which not always corroborate the binder results. However, from this study, it can be concluded that antiaging capability and mixture performance of CR modified asphalt binders are enhanced.Moreover, a reduction in complex modulus for the PmB and the one extracted from Mix B was observed. This confirmed the positive softening effect caused by the use of rejuvenator that resulted in values near those obtained for the original mixtures. Nevertheless, this was not observed for the Mix A. Recently, it was discussed that a potential absorption of the rejuvenating agent by the CR particles could have a side effect on the response . In thisIn general, the two CR experimental mixtures showed adequate behavior in comparison to the reference mixture with PmB. Nevertheless, further work is required to optimize their design in order to meet the requirements specified in the Swiss standard (ITSR > 70%).Regardless the type of CR, the experimental asphalt mixtures were found to be less susceptible to aging than the reference mixture (PmB).It was observed that the effect of the CR particles as elastic aggregate was more significant at high temperatures.The differences found in the volumetric properties (air void content reduction) and in the rheological response of the binder from recycled mixtures (rejuvenator capability) suggest that the polymer coating changes the resulting performance of the CR negatively.Further recommendations include the validation of the experimental results through specific tests (resistance to fatigue and stiffness modulus at different temperatures). Likewise, it will be imperative to take into consideration other parameters at industrial scale .In this study, the influence of aging and the recyclability potential of asphalt mixtures modified with CR by the dry process were evaluated. Two SDA mixtures modified with two different types of CR were prepared in the laboratory and compared with a conventional mixture with polymer modified bitumen used as reference. After the analysis of the results obtained from the mechanical and rheological tests, the following conclusions can be drawn:


This paper presents a novel approach to a complex process of electrical capacitance tomography (ECT) measurement data analysis. ECT is frequently employed for non-invasive monitoring of industrial process phenomena. Proposed methodology is based on the premeditated integration of the spatial and temporal relations inherent in the measurement records into the workflow of the analysis procedure. We propose a concept of interactive timeline that enables arranging data visualization according to the user’s current focus along the process of analysis. We evaluated the proposed method using a prototype system in a task-based user study conducted with a group of domain experts. The evaluation is based on gravitational silo flow measurement datasets. Proposed prototype system enables diverse data manipulation in a more natural way allowing the user to switch back and forth between space and time domains along the data analysis trail. Experiments with the prototype system showed that the accuracy and completion times have significantly improved in comparison to the performance measured in the baseline condition. Additionally, the participants reported decreased physical load with improved efficiency measured with NASA task load index. Finally, a short discussion coupled with directions for the future of interactive spatio-temporal ECT measurement data analysis conclude the paper. Industrial process tomography systems belong to a special class of non-invasive and non-intrusive sensing systems. The most prominent feature of tomography system is the capability to measure and visualize the interior of industrial reactors and installations, the ones constructed with the use of opaque materials ,2,3. TheBesides the ultimate goal of using process tomography technology as an element of the control system, its secondary goal is to investigate the processes as ECT is well adapted for it. It is a perfect tool for understanding the phenomena and changes taking place within the ongoing flows ,2,20. CoHence, there is a critical need to provide efficient paradigms for the development of the appropriate software tools for visualizing, browsing and manipulating measurement records’ datasets that enhance the current capacity of the widely used, domain-standard data analysis software packages such as MATLAB ,26,27. NMoreover, experts currently have little support in the form of dedicated high-quality tomography measurement data analysis and visualization solutions. In particular, the inherent relations between the time stamps (conveyed in sequences of measurement data frames) for the ongoing process and the analyzed spatial features (visible in reconstructed 2D and 3D images) are extremely important are extremely important in the aspect of interpretation. And yet, so far these are the most difficult features to be translated into convenient software analysis and manipulation tools . ApplyinThe main contribution of this work is a novel method of working with process tomography measurement data aiming at disclosing specific important information relevant to the context of the industrial process state. The proposed method is based on incorporation of the specifics of the measurement data consisting of close, spatio-temporal relations, inherent in the monitored process and preserved by the measurement tool. We show a method of contextual data analysis that arranges data visuals around the current user focus by constantly adjusting the adjacent data following along user analysis’ workflow. This novel method is based on the concept of the interactive timeline layer, which organizes the data composition in compliance with the specific purpose of the ongoing analysis. We incorporated the spatio-temporal relations into the core of the proposed method to increase effectiveness of analysis. The proposed interactive mechanism for contextual switching between time and space domains has been carefully examined in controlled laboratory settings. The approach was verified in a task-based user study and the evaluation was conducted using ECT data for the gravitational flow of bulk solids in silos . EvaluatThe rest of the paper is arranged as follows. Process tomography provides numerous measurement and exploration tools, facilitating the online monitoring and diagnostics of industrial processes in a non-invasive manner. In addition to that, the captured data enable further, extensive analysis of the process, which reveals the causes of possible disturbances and provides functional parameters. These outcomes may eventually lead to better design of process facilities as well as improved control systems. . The maiThe main goal of this work is to explore spatio-temporal relations inherent in the tomography measurement data. Consequently, we chose an ordinary, industry-widespread, representative process of bulk solid flow as an exemplary case of ECT-monitored industrial flow. In particular, we examine the procedure of analysis and interpretation of gravitational bulk solid silo flow as an instance of the entire class of easily generalizable industrial measurement problems.The full set of data, received in the form of a temporal sequence of raw measurement data as well as spatial 2D or 3D images, provides a basis for process analysis. Process tomography measurement datasets can contain a substantial volume of files, which first must be saved on a disc and later analyzed in an effective way . Figure When it comes to storing and processing 3D reconstructed imagery, the numbers again rise substantially. Each 3D image for a measurement frame captured with a 32-electrode sensor is at least 5 MB in size (or more depending on the density of the 3D reconstruction mesh that controls the output resolution). This gives an additional output of approximately 5 GB for every 1000 measurement frames. For nonlinear, iterative image reconstruction algorithms (where the sensitivity matrix is updated for each iteration of the reconstruction), up to more than 100 intermediate stages may be stored for each frame. When 1 GB of 3D data is recorded for each measurement frame, (for both the sensitivity matrix and the resulting intermediate image), this gives around 1 TB for every 1000 frames. Specific properties of the ECT process tomography data make it necessary for it to be analyzed in a broader context than just the context of the isolated measurement records. Understanding the process based on one experimental dataset requires analysis of the other datasets as well.Finding the key changes in measured values, over both space and time, and correlating them with a change in the state of the monitored process is the main challenge for researchers involved in the development of flow control systems . The curElectrical capacitance tomography data investigations can be split into a three-level workflow, as illustrated in Block 2  as a mechanism for constant positioning of the rendered data around a common center of the analysis procedure regardless of the current focus of the user.ITL contextually synchronizes the focal point of the analysis with the time stamp position on the actual recorded data process timeline. The context of synchronization is meant to couple the time position together with its nearest neighborhood, i.e., an additional, extra set of adjacent preceding and subsequent data. It is intended to be included within the pre-rendered chunk of data easily available to the user continuously throughout the entire workflow. Contextual neighborhood is composed of measurement data related to both space and time features representing sequence from a fixed length adjacent interval. The key asset of the proposed methodology is the systematic approach to data analysis procedure organized around the spatio-temporal data presentation regardless of the examined phenomena. The consistent arrangement of the data around the current focus chunk is a main advantage in comparison to the more chaotic data analysis loops employed by the experts for different analysis purposes as it can be observed in To experimentally verify the proposed methodology, the solution illustrated in In addition to that, INFORVIS is designed to simplify and provide more user-intuitive manner of data handling and analysis. It supports various forms of data visualization in different arrangements, while facilitating proper navigation through both raw and processed data in compliance with baseline standards ,15. FiguThe prototype data analysis system was built to facilitate following the inherent measurement data relations during analysis. It was examined thoroughly using ECT measurement data captured for the gravitational silo flow of granular material, since this class of processes is characterized by dynamic phenomena occurring in the spatio-temporal domains. Initial design requirements were drawn from observation and semi-structured interviews with domain experts conducted after a shadowing study with baseline methods typically used in tomography measurement data analysis. Providing intuitive and comfortable mechanisms for browsing, managing and exploring the information in terms of continuous connections in time and space turned out to be a priority. To avoid introducing unknown interfaces, yet retain a tangible UI mode, a multi-touch surface was chosen. Multi-touch surface operation was implemented to avoid additional initial cognitive effort on top of the need for the user to learn the novel, proposed features for data manipulation. Therefore, intuitive gestures such as those used with smartphones and tablets, i.e., tapping, zooming, scrolling, pinching and panning were used. Such design and implementation minimized the need for additional navigation slidebars and icons, while preserving task-solving functionality. The proposed design was tested successfully with small tablets, flipped and fixed medium size tabletop displays (20 inch), and full screen multi-touch 40 inch tabletop devices working under different principles of operation . Synchronization between the devices and platforms is possible, enabling on-site investigation and collaborative exploration by remote expert users.The ultimate goal of ECT data analysis is to properly acquire measurements and interpret the process evolving inside the examined installation (the flow loop). Typically, the first choice of the operator during the analysis of flow parameters are the concentration profiles in the form of average plot diagrams or raw measurement records acquired from a single pair of electrodes. Later, the raw measurement data is transformed into images of material distribution inside the sensor space. These images allow further analysis thanks to generation of corresponding graphs and tomograms, which are employed to analyze various aspects of the investigated process . A variety of visualization parameters can be helpful to domain experts. Some experts rely on average concentration visuals mainly for entire cross-sectional reconstructions, others generate profiles for single pixels located in characteristic regions of cross-sections and couple them with slice-based topograms. Both solutions are based on the temporal relations between these spatial elements of cross-sectional parameters. The bottom stripe displaying consecutive 2D reconstructed images for subsequent measurement frames works as a contextual timeline control. It can easily be activated by a single tap on a chosen image. The contextual neighborhood is assigned a minimal fixed length in terms of total interval centered on the focal point of process timeline. It is possible to adjust the length of the neighborhood interval depending on the context of the analysis. Therefore, this is not only the implementation of the ITL concept but also an additional opportunity for further research on matching the appropriate neighborhood in a specific, proper context. The rest of the interface adjusts the current view to follow the timeline-indicated current frame, regardless of whether a magnified 2D image, topogram or plot is displayed at that particular moment in the main window above. The important feature is that setting the current focus is possible not only on the timeline bar but anywhere regardless of which of the visuals is analyzed. Transitioning between various visuals is possible by using the right-hand side panel, in order to ease tracing data features by switching smoothly between the visuals without losing the current time point on the way.To evaluate the proposed methodology, a user study was conducted in controlled laboratory settings. First, participants followed data analysis scenarios to complete a set of given, specific tasks. During this stage, their actions were being recorded to investigate the workflow and performance. Results such as the task completion times were calculated based on the recorded actions. Additionally, some of the comments given by the experts during the study were extracted for further analysis. Secondly, immediately after the completing the assigned experimental scenario, each participant was asked to complete the NASA Task Load Index survey.Q1.Would and how implementing the interactive timeline paradigm could improve the analytical procedures?Q2.Does the implementation of up-to-date information display and control technologies influence the performance of the users?We aim at developing a methodology that enables analyzing and understanding the changes occurring in the measurement data in a more efficient manner. Our secondary goal is to enable effective browsing of the data, finding faster, process-relevant information in the data, and simultaneously minimize user’s effort. Hence, our research questions are as follows:Hypothesis 1 (H1).Deployment of the interactive timeline focus paradigm improves performance defined in terms of task completion time and accuracy.Hypothesis 2 (H2).The ability to easily switch between forms of data presentation along the continuously synchronized spatio-temporal focus leads to the reduction of cognitive and workload indices.Hypothesis 3 (H3).Allowing users to employ multi-touch big screens and flipped displays coupled with a well-known set of control gestures gives users better comfort and improves their self-confidence when performing measurement data analysis.Therefore, as we decided to implement prototype system, we formulated the following hypotheses:To verify our research hypotheses we conducted a comparative, within-subjects user study using the baseline system and the proposed prototype system. We developed a study protocol and task-based study scenario specifically aimed at evaluating the H1 and H2 empirically through the set of quantitative and qualitative methods. Furthermore, we hope to draw conclusions on H3 based on mixed methods  employed throughout the experiments.The experimental evaluation was conducted within controlled laboratory settings of the Institute of Applied Computer Science, Lodz University of Technology (TUL). Two, computationally comparable, data analysis set-up arrangements were prepared to provide participants with the baseline and prototype systems access. Each system core was a modern PC station equipped with 32GB RAM memory, Intel i-7 7800 6-core CPU operating @ 3.5GHz and NVIDIA GeForce GTX1080Ti 11GB graphics operated under MS Windows 10 Pro x64 operating system, and was carefully installed and tested for seamless operation before employment.The main difference between the systems was the data analysis software available on these two environments. Baseline system was equipped with GNU Octave and proprietary Matlab numerical calculation software packages as well as standard PC built-in applications and internet connected Google Apps . Especially Octave and Matlab provided specialized data manipulation capacity. Both were configured based on the pre-study brief survey with domain experts, who listed software and optional toolboxes that would help ECT measurement data analysis. One of the interesting examples of a very specific applications required by the experts and installed on the baseline system was the EIDORS package that is a research, open software extension to the Matlab package dedicated to EIT  calculations and visualizations . In MatlTo evaluate the proposed approach to ECT data analysis, a task-based study was proposed. The scenario was based on the analysis of ECT data which was interpreted in the context of the gravitational flow of bulk materials. This particular process was chosen due to the prevalence of bulk material flows in industrial environments .Gravitational flow in silos is a typical process common in a variety of applications. It is an inherent constituent of both complex bulk solids systems and single containers used for the storage and protection of material. There is a wide variety of geometries, shapes and sizes available, depending on particular applications and material properties. The vast majority of solid materials in the industry is processed in the form of a granulate, most frequently transported with the use of pneumatic and gravitational flows. In the case of silo flow, the geometry of the tank, the properties of the granular material and the distance above the outlet determine various flow patterns, mainly regarding the mass and funnel . The behPrevious research was conducted at different facilities, with a range of silo sizes  ,36. TheoSand was chosen to imitate the granular material. A detailed description of the laboratory set-up can be found in . The iniDifferent flow parameters can be observed, analyzed and interpreted at different intervals. The phenomena that can be detected from the observations of the measurement data result from both the silo flow features as well as the ECT measurement modality properties. Interesting artifacts can be noticed within the intervals as well as on the boundaries (such as the border between stage II and stage III) . UnderstEvaluation of the proposed novel approach was based on an experiment in which experts were asked to solve a set of tasks, requiring them to conduct analysis and interpretation of ECT data related to gravitational silo flow. When trying to understand ECT data connected to the physical behavior of a process, it is usually necessary to often switch back and forth between temporal  and spatial  data visuals. The prepared scenarios included analysis of changes in measurement data important due to different flow process aspects. The experts analyzed silo flow behavior, determining symmetrical and non-symmetrical material distribution during silo discharge and the level of granular material vibrations and pulsations for different silo heights. The vibrations were analyzed in terms of their amplitude and frequency, and classified into three subsets  with relevant time intervals assigned. This procedure enabled the experts to determine the relations between the level of granulate and the vibration/pulsation parameters. During the study, the participants solved 10 tasks related to the nature of the funnel and mass flow. The ECT data were examined in both their spatial and temporal aspects. For the evaluation itself, 10 datasets of two types were prepared: 5 sets of measurement data for loose flow and 5 for dense flow. These two types of data refer to two types of flow conditions, since there were different artifacts included in the data for each of them. Generally, loose condition data may be more difficult to analyze, since some of the expected phenomena can be less evident, i.e., hard to spot in the data. Dense condition data can be characterized by easy to spot phenomena, such as a clearly visible boundary between the funnel and a stagnant zone, for example. The participants were asked to analyze different condition datasets in a randomized order, using two systems (the baseline and INFORVIS) to decrease the impact of bias.During the proposed data analysis tasks, different types of granular gravitational flow in the silo were investigated. ECT data were acquired during the gravitational flow of sand located in the silo model with 2 m height and 0.2 diameter. Possibility of initial packing of sand and wall roughness modification allows for generating four different flow conditions: (1) loose packing + smooth wall, (2) loose packing + rough wall, (3) dense packing + smooth wall and (4) dense packing + rough wall. The ECT sensor has been located at different heights above the outlet. Such arrangement of experiments allowed us to conduct the diagnostic of process behavior and described the relationship between flow and process condition.The tasks were carefully designed to explore the spatial and temporal features inherently incorporated in the process measurement data. The experts were given brief instructions and presented with the sheets that included a short introductory text and 10 tasks, each composed of a description or question. Some questions were in single or multiple-choice form, while others had space for open answers or optional graphical elements in the form of an image grid to be sketched on by the participants. The scenario was designed in a manner to enforce detailed flow analysis going deeper into the process diagnostics gradually along the experiment. Additionally, there were several steps that allowed users for reflection about the way they execute tasks. Generally, the scenario is a complete set of complementary, correlated instructions and shall not be neither executed incomplete nor executed in a random order. This note is important to emphasize that we designed the entire experimental comparison between the baseline and proposed approach holistically. Although it is easier to explain their purposes in groups. Hence, tasks can be classified into three main clusters. The first set of tasks was designed to execute general, qualitative, decisive (judgement) instructions . These were important to introduce participants into the working context of the study and allowed to assess users’ understanding of the analyzed process. These tasks allowed also for reflection on the differences between the baseline and proposed methods in terms of workflow and workload. The second group can be described as related mainly to performance. These required users to track down, indicate and describe specific phenomena . These tasks were designed to explore users performance based on their workflow. In addition to that, users could reflect on their usage of visuals and adjust their performance based on the technical requirements. The third type of tasks was related to assess, estimate, calculate and measure particular recorded flow effects . This group of instructions was aimed at measuring accuracy with respect to particular conditions and partially in relation to workflow performance.In the first task (T1), participant analyzed data to indicate the flow type at a specific height (funnel/mass or mixed flow type). T2 was related to the investigation of pulsations localization. Additionally, the users were required to estimate basic parameters using empty cross-sectional mesh for sketching and note taking. They were encouraged to include numerical values, required phenomena and discovered effects. Next two tasks  explored the issue of symmetry analysis of granular material distribution (concentration) in the silo cross-section and its impact on occurring vibrations/pulsations. Both tasks required users to illustrate their conclusions with sketches and optionally numerical values. Following 2 tasks  were related to tracking the particular flow period in search of specific effects and describing them both in a qualitative and quantitative way. T7 was solely devoted to denoting the workflow sequence that helped participant to resolve the previous tasks. T8 was again focused on quantitatively estimating and mapping the analyzed phenomena in cross-sectional space. Furthermore, in the T8, participants were given an opportunity to make comments in a form of notes. Subsequently, T9 revised the estimated qualitative character of the examined flow coupled with quick quantitative estimation of predominant character over time. Task sequence concluded with T10 where participants were to indicate practical elements of the employed workflow that were most helpful on the way to solve T9.To give the reader a deeper insight into the employed experimental scenario we present two representative tasks, namely T4 and T8, that require participants to both search for, estimate or calculate and finally indicate the resulting answers and map onto the space in form sketch. The other task, T8 is shown on the right in The study consisted of n = 17 participants, each of whom were experts at the analysis of ECT measurement data. Results of 3 participants  were excluded due to discontinuation of the scenario execution, participant drop-out and technical problems resulting in false timing results. Participants gave written consent and were relaxed before taking the experiments. Each of the participants was presented with the functionalities of both the baseline as well as the INFORVIS systems and given hands-on practice on an exemplary dataset. Subsequently, participants were shortly instructed about the experimental scenario and received a 5-page answer sheet. The experimental conditions were assigned almost symmetrically in a random way (9 out of 17 started with baseline and 8 out 17 started with INFORVIS). Even though the answer sheets were the same, i.e., independent of the condition, each participant was given only 1 answer sheet required for current condition just before starting the tasks. Entire study sessions were video and audio recorded for further analysis. Participants, answer sheets and recordings were coded and anonymized. Video and audio material was deleted after analysis.As we sook to verify the hypotheses stated in Upon finishing the tasks, the participants completed a survey concerning their overall user experience, their satisfaction with the system interface and the degree of challenge. In order to measure the effort required for task completion, a task load index was employed. The NASA Task Load Index (TLX) is a subjective workload self-assessment tool for estimating human workload parameters that has been developed in the 1980s by NASA for human factor-based evaluation of machine interfaces. There are six main categories of TLX self-evaluation: mental, physical and temporal demands, performance, effort and frustration. Further details on this method can be found in .To analyze the rest of quantitative feedback we collected all the remarks noted by the participants in the answer sheets and encoded auditory records from the videos. After completing the scenario analysis, the users were also debriefed in a semi-structured interview.The first quantitative results gathered for the experimental study were the time of completion (TCT). The TCT was measured for each of the tasks performed by the participants. The total aggregated TCT for completing all the tasks by each participant was also calculated by encoding the experimental videos. There is another TCT analysis presented on the bar diagram on the right-hand side of The next and presumably the most important parameter we examined was the accuracy. On the left in It is worth noting that the accuracy for the first three tasks was not perfect, especially in the case of the baseline set-up. In particular, correct answers were below 85% for Task #1 (multiple-choice question regarding the choice of flow type), while with the aid of INFORVIS there was 100% accuracy for this task. Observations of participants and careful analysis of the recorded videos revealed that they were more self-convinced about the correctness of the quick choices using baseline methods, so they did not double-check all the possible forms of data visualizations in order to come to a decision. Some of them later realized their error  and corrected their answer, yet not all of them did so. This is one of the elements of data workflow where easy access to spatio-temporal dependent relations between the visuals can significantly help achieve much better interpretation. Participants were likely to use the topograms in addition to basic plots and the 2D cross-sectional images during analysis using the INFORVIS system, whereas when using baseline methods, the topograms were mostly omitted.Another key aspect of the evaluation was the self-estimation of workload when completing the task with the aid of baseline methods vs. the proposed approach implemented in the INFORVIS prototype system. The results of NASA TLX show the overall slight superiority of the proposed INFORVIS system over the baseline set-up, as shown in Interestingly, the participants considerably underestimated their performance when using both systems. The average TLX scores for individual categories were also rather low compared to similar scores for any common web application or everyday interfaces. Interviews with participants revealed that the main reason for this was the perceived high difficulty of the entire analysis experimental scenario and low self-confidence caused by non-standard character of the required assignment. In fact, real, measured performance scores in terms of both the accuracy and completion times were far more than good  to correct answers to previous tasks.The participants were furthermore asked to assess the efficiency and the convenience of operating each type of visual. Graphs were rated as definitely the easiest to use and efficient form of visual depiction. Analysis using reconstructed images were satisfactory, while managing them was rated as inconvenient. On the other hand, the tomograms were described as convenient to use, although not sufficiently useful in terms of data exploration. Interestingly, the topograms were used far more often when working with INFORVIS and proved to speed up the TCT. They also enabled correct conclusions to be drawn from the data faster than traditionally, when topograms were mostly omitted.Other exciting observations were made by shadowing the participants as they completed the tasks, as well as from video analysis and post-study interviews with the experts. Interestingly, four of the experts reported finding interesting  features in the data that were not expected of them. Participants made comments indicating their research-related nature that was not possible to explain on the fly during the ongoing experiment. The answer sheets prepared for the study had no appropriate forms to note these unexpected findings. All the findings concerned unexpected patterns of pulsations and were related to the task of vibration analysis. All the cases had been found using INFORVIS prototype, when switching back and forth between the temporal concentration graphs generated by the participants for different locations in 2D cross-sectional space and the corresponding plots or reconstructed images. The sample is statistically insufficient to draw any definite conclusions, yet there were no similar findings reported for the baseline method. Moreover, two experts concluded it would have been almost impossible to reveal the same phenomena in the data using the standard baseline set-up. The usage of the multi-touch screens and the flipped-enabled display was also analyzed. Although we noticed a variety of approaches and different levels of expertise in productive use of multi-touch features of computer and application control there were no common conclusion that could be drawn to our best knowledge from this particular study. Moreover, flipped positioning of the screen was neither anticipated nor expected by the participants, hence no conclusions on that topic can be drawn from this research, either.The study revealed that there is a need for more accessible and intuitive tools, which could significantly enhance the workflow of tomographic data analysis. Expert comments provided insights that it is not only accuracy that is required, but also a greater emphasis on enabling intuitive data exploration. As specialist teams are becoming more and more interdisciplinary, engaging non-technological experts, developing interfaces for data analysis becomes more important. Therefore, careful design with respect to the inherent spatio-temporal properties of the data corresponding to flow phenomena occurring in industrial installations could facilitate more efficient analysis and proper interpretation of data.Research question Q1  and related hypotheses H1 (employing ITL mechanism for improving performance) and H2 (ease of time-space data manipulation for reduction of operator workload) have been successfully verified and positively confirmed. Results of scenario-based experiments related to task completion times  this area deserves deeper exploration in terms of novel multimodal interaction techniques pervasively penetrating our daily life .This work shows a novel approach towards interactive spatio-temporal, process tomography measurement data analysis. The proposed interactive timeline concept is demonstrated using a prototype system for electrical capacitance tomography data and has been evaluated with a task-based user study. Experiments were conducted on gravitational bulk solids flow ECT datasets of diverse levels of interpretation difficulty. Quantitative results showed that the proposed approach assisted experts by automatically providing required visuals  that lead to improved accuracy, reduced task completion times and decreased workload. Moreover, a user study suggested that the convenience of switching between the space and time domains in different arrangements enabled more detailed and accurate interpretation. The proposed approach outperforms the traditional method of data exploration and interpretation, no matter the level of industrial process measurement data difficulty, as demonstrated for two conditions for gravitational flow in silos (loose and dense packing density). The principles of operation for the novel measurement data analysis tool can be transferred to other types of measurement modalities, both for process tomography and other classes, especially for incomplete or insufficient data or whenever any data uncertainty is present. There is great potential for employing the proposed solution to other industrial measurement data captured from different processes. The most interesting application would be to employ this type of analysis as a first step on the way to automating data processing tasks that are currently impossible to automate. Preparing classes of annotated data for crowd sourcing and machine learning systems could be an interesting example.