Load Transfer Assembly

A load transfer apparatus accommodates movement between adjacent concrete slabs. The load transfer apparatus includes a spine in a form of an elongated hinge having a longitudinal axis A. A first dowel and a second dowel project radially from the spine and are located at two spaced points along said longitudinal axis A

Effects of Hinged Dowel System on the Performance of Concrete Pavement Joints

Concrete joint failure is a major distress mode in rigid pavements. Improving the joint performance in concrete pavements could yield substantial savings in terms of reduced maintenance and rehabilitation costs. The newly developed Hinged Dowel System (HDS) is a means for transferring loads across the concrete pavement joints. The HDS was patented as a new invention by the United States Patent and Trademark Office, and it is envisioned that it could significantly reduce the potential for joint failure in concrete pavements. The HDS assembly comprises a number of dowel bars and a collective hinge provided at the mid-length of the dowel bars. A finite element analysis showed that the application of HDS reduces the shear stress in concrete pavement joints by approximately 15% when compared to the conventional dowel bars. This amount of reduction in shear stress could translate into a significant reduction in shear-induced failures in concrete pavements. The HDS includes mechanisms which would allow a horizontal slip condition for the dowel bars imbedded in concrete. Moreover, these mechanisms eliminate the punching stress at the dowel tip, which is often induced by thermal expansion of the concrete slabs. The hinge in the HDS gives the concrete slab joints a degree of flexibility to reduce the stresses caused by daily curling and warping of slabs, and seasonal expansion and contraction. In addition to installation in new concrete pavements, the HDS could be utilized in retrofit of old concrete pavements. Finally, the HDS eliminates most construction-related issues associated with the installation of dowel bars, such as dowel bar misalignment and full-depth joint cut

Experimental studies on the progressive collapse of building structures: A review and discussion on dynamic column removal techniques

Dynamic progressive collapse tests are becoming more and more popular in recent years since this approach captures the real structural behavior more robustly, and progressive collapse response more accurately. The results of dynamic tests are of great importance for defining computational models and improving current codes and guidelines. Even for static tests and simulations, the dynamic effects should be indirectly considered, namely by including the dynamic amplification factors. The adopted dynamic column removal approach is the most important and challenging aspect of the dynamic progressive collapse tests. While several methods for dynamic column removal have already been suggested and implemented, a comprehensive discussion of the techniques is missing. In this regard, a comprehensive review of the available literature is first presented. Current experimental techniques for dynamic column removal are categorized into three main groups, i.e., quick-release device, dummy column, and explosion technique, and the underlying concepts and applied methodologies are compared and contrasted. Finally, future needs are highlighted and possible improvements for the current methodologies are also discussed

Assessment of radiofrequency ablation technique in development of aortic valve stenosis in rabbits

Purpose: To develop a minimally invasive and reproducible model of aortic stenosis in rabbits using radiofrequency ablation technique (RFA). Material and methods: Eleven rabbits were studied. A radiofrequency ablation catheter was introduced via the femoral artery and advanced to the aortic valve area under fluoroscopic control. In three rabbits radiofrequency energies, at 5 W, 10 W and 15 W respectively, were applied thrice for 90 sec. In eight rabbits, energy of 15 W was applied for the same time periods. The velocity of the blood through the aortic valve was determined by color Doppler ultrasound immediately before and after ablation and after six weeks. After six weeks the rabbits were sacrificed and the aortic valve was examined macroscopically. Results: Peak systolic velocity (PSV) was similar at the time of ablation and after six weeks in eight of the nine surviving rabbits, and had increased from 1.1 to 1.75 m/s in one rabbit. Two rabbits developed aortic insufficiencies visualized by color Doppler. No macroscopic changes were seen at the aortic valve area 6 weeks after ablation. Conclusion: In the current study we did not succeed in inducing aortic valve damage/fibrosis using different RFA energies. Inadequate RFA power or inappropriate positioning of the RFA catheter could be limitations of our study

Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism

The synchronously rotating G stars in the detached, short-period (0.7 d), partially eclipsing binary, ER Vul, are the most chromospherically active solar-type stars known. We have monitored activity in the Ca II H & K reversals for almost an entire orbit. Rucinski's Broadening Function Formalism allows the photospheric contribution to be objectively subtracted from the highly blended spectra. The power of the BF technique is also demonstrated by the good agreement of radial velocities with those measured by others from less crowded spectral regions. In addition to strong Ca II emission from the primary and secondary, there appears to be a high-velocity stream flowing onto the secondary where it stimulates a large active region on the surface 30 - 40 degrees in advance of the sub-binary longitude. A model light curve with a spot centered on the same longitude also gives the best fit to the observed light curve. A flare with approximately 13% more power than at other phases was detected in one spectrum. We suggest ER Vul may offer a magnified view of the more subtle chromospheric effects synchronized to planetary revolution seen in certain `51 Peg'-type systems.Comment: Accepted to AJ; 17 pages and 16 figure

Study the Changes of Some Water Relations and Net Photosynthesis of Three Iranian Melon Population (Cucumis melo) under Water Deficit Stress

Introduction Drought stress is one of the most common environmental stresses that limits agricultural production through disruption of physiological processes and reduces plant performance. Since in most parts of the world, including in Iran, melon plants and generally pumpkins are cultivated in hot and dry areas, and in these areas the main challenge is due to the limitation of suitable water for agriculture, the possibility of various types of stress, including  water deficit stress (partial or severe) in the cultivation of these plants is relatively high. From this point of view, it seems necessary to study and know the tolerant cultivars and masses and ways to improve water management. Among the physiological characteristics, leaf water status, membrane stability, photosynthesis changes and related factors are of special importance in relation to tolerance of stressful conditions and especially dehydration. A review of scientific sources shows that due to the relative importance of melons among fruit vegetables, no comprehensive research has been done on the effect of water stress on the yield and stress level evaluation indicators in Garmak and Dudaim groups. This research has tried to investigate and evaluate this issue in some products of this group of vegetables that have been less studied.   Materials and Methods This experiment was carried out in the form of a split plot design in the form of randomized complete blocks and in four replications in the Mahan greenhouse complex located 25 km from Kerman province. Experimental treatments include; There were three plants (Shahdad and Isfahan cantaloupe (Garmak) and Birjand dudaim (Cucumis melo group dudaim)) and three levels of irrigation in order to apply stress (starting irrigation at matric potentials of -45 (control), -55 and -65 kPa). The parameters of net photosynthesis rate, stomatal conductance, leaf transpiration rate, leaf chlorophyll index, water potential, osmosis and turgor potential of leaves, water use efficiency and leaf relative humidity were measured and evaluated.   Results and Discussion Based on the results of the first and third tables, the three population were different in the changes in the net rate of photosynthesis under different levels of dehydration stress, but the change process in them was largely similar. The highest rate of net photosynthesis and leaf stomatal conductance was obtained in Isfahan cantaloupe population plants under control irrigation (-45 kPa), which, of course, did not have a significant difference with plants under -55 kPa dehydration stress, and the lowest rate of these traits in Birjand dudaim under irrigation at matric potential -65 kPa was measured. A more severe level of dehydration stress (starting irrigation at matric potential of -65 kPa) reduced the net photosynthetic rate in all three plants compared to control irrigation (-45 kPa). It seems that under the conditions of this experiment, the reduction of the relative humidity of the leaves occurs following the reduction of the water potential in the leaves and leads to the closing of the stomata in order to increase the resistance of the mesophyll cells against the dehydration stress and parallel to these changes, the reduction it happens in the amount of stomatal conductance and as a result the rate of net photosynthesis. The rate of leaf transpiration in matric potentials of -55 and -65 kPa has decreased significantly compared to control irrigation. The decrease in transpiration rate in plants under stress is probably due to stomatal closure and reduction of stomatal conductance. Plants under stress prevent excessive water loss through transpiration by regulating stomata. Based on the results of the second and fourth tables, by measuring the water potential, osmosis and turgor potential of the leaves of the three population used, it was shown that the water potential of the leaf decreased with the increase in the water stress levels. The slope of this decrease is such that the potential values are equal to the osmotic potential values of the leaf and the turgor potential, which is the result of the difference between the osmotic and water potentials of the leaf, also decreases, but it is the turgor pressure that has increased and in a more positive way. even at the end of the stress period and at the most extreme level of stress, it reaches zero. This same turgor pressure maintains the normal state of the membrane in cells under dehydration stress. In fact, the extreme level of water stress in this experiment significantly reduced the osmotic potential of the leaf. The highest amount of osmotic potential (8.5 Bar) for these plants was obtained in the usual or control irrigation treatment and the lowest (22 Bar) in the more severe level of dehydration stress treatment (watering as soon as the matric potential reaches -65 kPa) was obtained. At matric potentials of -45 and -55, there was no significant difference between the three population in terms of leaf relative humidity percentage, but in Garmak and Dudaim populations, the relative humidity of leaves was significantly reduced by applying stress at the matric potential of -65 kPa. This is despite the fact that in the Isfahan cantaloupe, the decrease in the relative humidity of the leaf was not significant. The existence of this difference in the reduction of the relative humidity of the leaves in the conditions of stress between the three plants may be due to the genetic differences in the ability of the stomata of the plants to lose water. In fact, more drought tolerant population (Isfahan Garmak) compared to Shahdad Garmak and Birjand dudaim have better maintained relative humidity until the end of the stress.    Conclusion Plants with the ability to regulate osmosis can be considered as drought tolerant plants. This adjustment in the plants of this experiment occurred in the condition that in all three population, the osmotic potential decreased by -19 to -22 Bar. This event is to some extent guaranteeing the performance of pure photosynthesis, although at a low rate in these plants, in the condition that the water potential of the cell has become negative at the level of severe water deficit stress, at the end of growth

Experimental study of fire containment using water mist curtains in a reduced-scale deck of a ro-ro ship

Experiments have been conducted to evaluate the containment of smoke and heat using water mist curtains in a model setup of a ro-ro ship's cargo deck with a scale of 1:13, providing practical insights into the application of such fire protection systems in the cargo deck as well as valuable data for future numerical simulations. In this regard, the requirements of the international convention of Safety of Life at Sea (SOLAS) are studied for the side openings of so-called ‘open decks’ in comparison with ‘closed decks’, especially to examine the feasibility of using water mist curtains for creating isolated subdivisions in the ro-ro space as a fire management strategy. The water mist curtains are created with one or two rows of water mist nozzles at pressures ranging from 3 to 8 bar, while the source of smoke and heat is a liquid pool fire, and inert cargo items are used in some experiments. Correspondingly, the interaction between the water mist curtain(s) and the fire is evaluated in terms of its heat release rate, and the containment effect is quantified via measurements of smoke flow through the deck and through the windows, concentrations of gaseous species, as well as gas temperatures at various key locations. The study shows that water mist curtains have a strong effect on fire dynamics and smoke propagation, but containment is dependent on the configuration of side openings and the location of fire, among other important factors

How increasingly powerful PRE modeling tools allow to unlock the full potential of FRP and RDRP in aqueous emulsion

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Reporting a rare form of myopathy, myopathy with extrapyramidal signs, in an Iranian family using next generation sequencing: A case report

Background: Myopathy with extrapyramidal signs (MPXPS) is an autosomal recessive mitochondrial disorder which is caused by mutation in mitochondrial calcium uptake 1 (MICU1) gene located on chromosome 10q22.1. Next Generation Sequencing (NGS) technology is the most effective method for identification of pathogenic variants with the ability to overcome some limitations which Sanger sequencing may encountered. There are few reports on this rare disease around the world and here in this study we first revealed genetic identification of two affected individuals in an Iranian family with a novel mutation. Case presentation: The proband was a 5-year-old girl from consanguenous parents. She was first clinically suspicious of affected with limb-girdle muscular dystrophy (LGMD). Muscle biopsy studies and autozygosity mapping, using four short tandem repeat (STR) markers linked to 6 genes of the most prevalent forms of LGMD, ruled out calpainopathy, dysferlinopathy, and sarcoglycanopathis. DNA sample of the proband was sent for NGS. Whole exome sequencing (WES) revealed a novel mutation c.1295delA in exon 13 of MICU1 gene. This homozygous deletion creates a frameshift and a premature stop codon downstream of canonical EF4 calcium binding motif of MICU1. According to the American College of Medical Genetics and Genomics (ACMG) guidline for sequence interpretation, this variant was a pathogenic one. Sanger sequencing in all family members confirmed the results of the WES. Conclusions: This study was the first report of MPXPS in Iranian population which also revealed a novel mutation in the MICU1 gene. © 2020 The Author(s)

Characterization of active and infiltrative tumorous subregions from normal tissue in brain gliomas using multiparametric MRI

Background: Targeted localized biopsies and treatments for diffuse gliomas rely on accurate identification of tissue subregions, for which current MRI techniques lack specificity. Purpose: To explore the complementary and competitive roles of a variety of conventional and quantitative MRI methods for distinguishing subregions of brain gliomas. Study Type: Prospective. Population: Fifty‐one tissue specimens were collected using image‐guided localized biopsy surgery from 10 patients with newly diagnosed gliomas. Field Strength/Sequence: Conventional and quantitative MR images consisting of pre‐ and postcontrast T1w, T2w, T2‐FLAIR, T2‐relaxometry, DWI, DTI, IVIM, and DSC‐MRI were acquired preoperatively at 3T. Assessment: Biopsy specimens were histopathologically attributed to glioma tissue subregion categories of active tumor (AT), infiltrative edema (IE), and normal tissue (NT) subregions. For each tissue sample, a feature vector comprising 15 MRI‐based parameters was derived from preoperative images and assessed by a machine learning algorithm to determine the best multiparametric feature combination for characterizing the tissue subregions. Statistical Tests: For discrimination of AT, IE, and NT subregions, a one‐way analysis of variance (ANOVA) test and for pairwise tissue subregion differentiation, Tukey honest significant difference, and Games‐Howell tests were applied (P < 0.05). Cross‐validated feature selection and classification methods were implemented for identification of accurate multiparametric MRI parameter combination. Results: After exclusion of 17 tissue specimens, 34 samples (AT = 6, IE = 20, and NT = 8) were considered for analysis. Highest accuracies and statistically significant differences for discrimination of IE from NT and AT from NT were observed for diffusion‐based parameters (AUCs >90%), and the perfusion‐derived parameter as the most accurate feature in distinguishing IE from AT. A combination of “CBV, MD, T2_ISO, FLAIR” parameters showed high diagnostic performance for identification of the three subregions (AUC ∼90%). Data Conclusion: Integration of a few quantitative along with conventional MRI parameters may provide a potential multiparametric imaging biomarker for predicting the histopathologically proven glioma tissue subregions