The main goal of this study is to determine the aerodynamic performance and to characterize unsteady flows in a high-speed high-reaction pre-whirl axial flow fan. The pressure waves’ main diametrical modes where two blades interact with two vanes and their sequences are predicted. There are mainly two mechanisms of IGV-rotor interactions identified; the first is attributed to the potential effect whereas the second is due to the wake-blade interaction and the advection of wake mixing into the blades’ passages. Both effects are dependent on the circumferential positions of blades and the axial inter-distance between IGV and rotor. The time mode analyses of pressure fluctuations recorded from different monitor points are determined and the frequencies of prevailing modes and those related to the vortical flow structure through the components are also identified. The understanding of vanes and blade rows interactions at various axial inter-distances is an important step in determining the beneficial and detrimental effects on the design of high performance axial fan stage.

Tunnels had been undergone accidental and intentional blast in the past. An analysis of a rock tunnel when subjected to internal blast loading has been presented in this paper. A three-dimensional finite element model of a huge rock mass comprising the tunnel has been developed in Abaqus/CAE. Diameter of the tunnel has been kept constant to a two-lane transportation tunnel. However, liner thickness of the concrete, overburden pressure on the tunnel has been varied to observe the response in different possible conditions. To incorporate the elastoplastic response of rock mass, Mohr-Coulomb constitutive material model has been considered. For modelling of trinitrotoluene (TNT), Jones-Wilkins-Lee material model has been adopted. Concrete Damage Plasticity material model has been adopted for tunnel lining. For the blast loading, Coupled-Eulerian-Lagrangian (CEL) model has been considered. Results highlight the importance of tunnel lining thickness and overburden depth while designing the tunnel in rocks. Under any amount of explosive, deep tunnels have been found to be safer than shallow tunnel.

High duty engineering component life is usually demonstrated through extensive testing and statistical analysis applied to empirical curve-fit equations. Because of this, the extent of the testing required is huge and costly: it must consider the load cycle range and test to high numbers of cycles. Furthermore, this testing must be repeated for every material, method of manufacture, and subsequent post-processing. Additive Manufacturing (AM) for high duty components has brought to the fore the question of the effect of porosity and surface roughness on fatigue life. Because there is relatively little service life experience, it is possible that the testing approach could also fail to represent conservatively the true life of a critical component. The authors propose the development of a fatigue model based on well-established engineering physics principles, by creating computational specimens with modelled surface roughness and porosity, and subjected to cyclic loading using Finite Element Analysis. They show that the combination of roughness features and sub-surface pores leads to an equivalent plastic strain distribution pattern that suggests an emergent physical process. Such a phenomenological understanding of the fatigue failure process should lead to improved life prediction techniques, more cost effective test procedures, and the development of better AM methods.

In this manuscript, a two-port semi-circular patch antenna with Koch curve fractals is presented as a suitable candidate for portable UWB communication systems. The proposed fractal array is engraved on a 1.57 mm thick FR-4 substrate with an overall array size of 30.5 × 47 × 1.64 mm3. The upper substrate layer consists of two microstrip-line fed semi-circular patches combined with two Koch curve fractals (optimized up to 2nd order of iteration) separated by a distance of λ/2. To mitigate the effect of mutual coupling between the radiating elements, the lower substrate layer consists of a reduced ground plane with a funnel-shaped decoupling structure. To achieve a high degree of isolation (S21/S12 ≤ -16.8 dB) between the ports of the proposed array, two rectangular and L-shaped slots (mirror images of each other) are etched from the upper surface of the reduced ground. The design and simulation of the proposed antenna array is implemented in CST MWS’18. The optimized fractal array covers the simulated frequency band from 4.395-10.184 GHz with a fractional bandwidth of 79.4 % (at a center frequency of 5.789 GHz) and provides a peak radiation efficiency of 88.8% (at 6.2 GHz frequency). The antenna diversity performance is analyzed in terms of envelope correlation coefficient (ECC ≤ 0.0021), diversity gain (DG ≥ 9.989), mean effective gain (MEG ≥ -3.7 dB), channel capacity loss (CCL ≤ 0.4 bits/s/Hz) and total active reflection coefficient (TARC ≤ -10 dB). The experimentally measured S-parameter results show a good match with the simulated ones.

The synthetic rubber industry is of great importance and it is present in the daily life of world society. BR (butadiene rubber or polybutadiene) is one of the most used polymers in this field, mainly in tire production. Therefore, the control of operational conditions and final properties of the polymer formed are important points to be studied as they are a challenge for the industry. Thus, the present work focus in simulate the batch polymerization of polybutadiene using the Aspen Plus software, where 1,3-butadiene, titanium tetrachloride, triethylaluminium and hexane were used as monomer, catalyst, co-catalyst and solvent, respectively. Four cases were simulated changing the number of catalyst sites in order to predict and compare the final properties of polybutadiene resins including the average molecular weights, the molecular weight distribution and the evolution of operation conditions that are used at plant to monitor the course of the reaction like the reaction temperature and pressure.

Recently, nanostructure perovskite oxides such as LaMO3 (M=Co, Ni, Fe, …) received attention in academic researches due to its catalytic properties. In this research, the LaCoO3 perovskite nanoparticles have been synthesized by single-step route via the sol-gel auto-combustion method. The precursors used in this method were lanthanum nitrate and cobalt nitrate, as metals sources dissolved in distilled water and also using PVP as a surfactant, Urea and glycine as an oxidizer. The sol formed at stirring stage at 60 °C continued by gelation through the water evaporation at 90 °C and then auto-combustion occurred. Product of combustion step was washed and centrifuged three times and later calcined at 600 °C for 2 h. As synthesized nanoparticles are characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and particle size analyzer (PSA). The characterization results proved the synthesis of nanoparticles below 100 nm with perovskite structure in narrow size distribution by using this method. The purity and size of nanoparticles vary depending on the fuel and fuel to oxidizer ratio.

Acquired drug resistance syndrom (ADR) is one of the most important features associated with tumor treatment and it is therefore a~topic of intensive studies. We present two simple mathematical models reflecting different mechanisms of ADR with some Darwinian effects included. These effects allow resistant cells to become sensitive again. Basing on this mathematical approach we conclude that for constant continuous treatment, if no Darwinian effects are present then once resistant cells appear, sensitive cells are eliminated after a long time, independently of the mechanism of acquiring the resistance. However, with Darwinian effects the situation is a little better as the sensitive cells are not completely eliminated but they are still outcompeted by the resistant ones. Moreover, if the therapy is stopped resistant cells become dominated by sensitive cells and the situation changes completely in comparison to the case without Darwinian effects. We discuss these mechanisms on the example of gliomas.

A new flow for Canadian young hydrologists: Key scientific challenges addressed by research cultural shiftsCaroline Aubry-Wake1, Lauren D. Somers2,3, Hayley Alcock4, Aspen M. Anderson5, Amin Azarkhish6, Samuel Bansah7, Nicole M. Bell8, Kelly Biagi9, Mariana Castaneda-Gonzalez10, Olivier Champagne9, Anna Chesnokova10, Devin Coone6, Tasha-Leigh J. Gauthier11, Uttam Ghimire6, Nathan Glas6, Dylan M. Hrach11, Oi Yin Lai14, Pierrick Lamontagne-Halle3, Nicolas R. Leroux1, Laura Lyon3, Sohom Mandal12, Bouchra R. Nasri13, Nataša Popović11, Tracy. E. Rankin14, Kabir Rasouli15, Alexis Robinson16, Palash Sanyal17, Nadine J. Shatilla9, 18, Brandon Van Huizen11, Sophie Wilkinson9, Jessica Williamson11, Majid Zaremehrjardy191 Centre for Hydrology, University of Saskatchewan, Saskatoon, SK, Canada2 Civil and Environmental Engineering, Massachusetts Institute of Technology, MA, USA3 Department of Earth and Planetary Sciences, McGill University, Montreal QC4 Department of Natural Resource Science, McGill University, Montreal, QC, Canada5 Department of Earth Sciences, Simon Fraser University, Burnaby, BC, Canada6 School of Engineering, University of Guelph, Ontario, ON, Canada7 Department of Geological Sciences, University of Manitoba, Winnipeg, Canada8 Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, Halifax, NS, Canada9 School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada.10 Department of Construction Engineering, École de technologie supérieure, Montreal, QC, Canada11 Department of Geography & Environmental Management, University of Waterloo, Waterloo, ON, Canada12 Department of Geography and Environmental Studies, Ryerson University, Toronto, ON, Canada13 Department of Mathematics and Statistics, McGill University, Montréal, Qc, Canada14 Geography Department, McGill University, Montreal, QC, Canada15 Meteorological Service of Canada, Environment and Climate Change Canada, Dorval, QC, Canada16 Department of Geography and Planning, University of Toronto, Toronto, ON17 Global Institute for Water Security, University of Saskatchewan.18 Lorax Environmental Services Ltd, Vancouver, BC, Canada.19 Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada

Boroxol (B3O3) rings and relevant hexagonal B3S3 structural blocks are ubiquitous in boron oxide/sulfide glasses, crystals, and high temperature liquids. However, the isolation of an ultimate heterocyclic B3O3 or B3S3 cluster in the free-standing form, with as few as six atoms, has been unsuccessful so far. We report on computational design of the simplest case of such a system: highly symmetric D3h B3S3+ (1A1) cluster. It is the well-defined global minimum on the potential energy surface, following global searches and electronic structure calculations at the B3LYP and single-point CCSD(T) levels. Chemical bonding analysis reveals an ideal system with skeleton Lewis B3S3 single bonds and unique double 6π/2σ aromaticity, which underlies its stability. The cluster turns out to be an inorganic analog of the 3,5-dehydrophenyl cation, a typical double π/σ aromatic system. It offers an example for chemical analogy between boron-based heterocyclic clusters and aromatic hydrocarbons. Double π/σ aromaticity is also a new concept in heterocyclic boron clusters. Prior systems such as borazine, boroxine, and boronyl boroxine only deal with π aromaticity as in benzene.

A new transport model is proposed for paraffin wax deposition onto a cold finger from flowing wax-containing oils. The model solves transient energy and mass balances simultaneously for a reversible first-order kinetic rate for precipitation of pseudo-single-component wax, and the effects of yield stress using a critical solid wax concentration to withstand flow-induced stress at the deposit-fluid interface, Cpi. The model can predict the time evolution of the deposit thickness, and the spatial and temporal evolution of temperature and wax concentration and was validated using experiments involving a cylindrical cold finger. We found that for oils with Cpi close to zero, the deposit thickness growth is dominated by heat transfer. However, mass transfer cannot be neglected as diffusion of wax into the deposit continues to take place even after the deposit has stopped growing. For oils with non-zero Cpi, the deposit growth is slow and accompanied by occasional sloughing.

Cerasus serrulata (Rosaceae) is an important flowering cherry resource. It is almost the most widely distributed species in the genus, mainly included in the subtropical and temperate China, which enables the geographic evolutionary pattern to be a representative. Besides, the morphological traits are greatly varied especially in ornamental characters. All of these makes Cerrasus serrulata a valuable research object. Thus, phylogeographic analysis was conducted to apprehend the spatial pattern and evolutionary history, which can also add insights into the phylogeography of the genus Cerasus and plants in subtropical and temperate China, as well as to deeper understand the genetic diversity and structure of the germplasm to make better and more effective utilization. A total of 327 individuals of 18 populations were collected. Three cpDNA fragments (matK, trnD-E, trnS-G) and the nuclear internal transcribed spacer (ITS) were utilized. The result showed a high genetic diversity both in species level and population level of Cerrasus serrulata. The high genetic differentiation among populations and the existence of phylogeographic structure in whole were detected. In addition, no bottleneck was identified. The the distribution pattern and center were formed before the LGM. Two geographical lineages were inferred. One was confined to Qingling Mountain and Taihang Mt. The other was from the Wuling Mt to Lu-Huang Mt, and then went northeast to the coast of Asia. Besides, taxonomic treatments of the Cerasus serrulata complex were reconsidered.

Rationale and objectives: Changes in, and predictors of, quality of life (QoL) among unstable angina patients are informative for both clinical and public health practice. However, there is little research on this topic, especially in healthcare settings with limited resources. This study aims to detect changes in QoL and its associated factors among patients with unstable angina after percutaneous coronary intervention. Methods: A quasi-experimental design was conducted with two repeated rounds of measurements, one month and three months after intervention, using the generic SF-36 questionnaire, in 120 patients from Vietnam National Heart Institute. A linear mixed-effects model was used to assess changes in patient QoL over time while adjusting for other covariates. Results: Only 2 out of 8 QoL subscales (social functioning and emotional well-being) declined after one month, but these tended to rise again after three months, while scores of all other QoL subscales increased. Adjusting for covariates, QoL increased slightly after one month of intervention (β=0.65, 95%CI=-0.86-2.16) but improved by almost 6 QoL points after 3 months (β=5.99, 95%CI=4.48-7.50). Four confounders significantly associated with a decline in QoL were older age, being retired, living in rural areas, and having abnormal troponin level. Conclusion: QoL of the patients with unstable angina improves significantly three months after intervention, rather than after one month. To increase QoL, it is important to address risk factors and to improve the quality of healthcare delivery.

Reduction in the torsional vibration of heavy rotors like turbo-generator rotor is important for the safe and efficient functioning of the power plant. In this paper theoretical study is performed to control the torsional vibration in the turbo-generator rotor using piezoelectric material as sensor and actuator. Polyvinylidene fluoride (PVDF) layer is used as sensor and actuator. Proportional and velocity feedback is used as control law. The variation in the electromagnetic torque of synchronous generator during various electrical faults is evaluated using dq0 model. Finite element method is used to model the rotor elements. The coupled equations are solved in MATLAB using Newmark-beta integration method. The coupling elements of turbine and generator are most susceptible to the shear failure so torsional vibration of coupled rotor on coupling elements are compare for controlled and uncontrolled scenario. Simulation results show that for actively controlled rotor significant reduction in the amplitude of torsional vibrations is observed.

The paper presents a novel technique to detect the solvents in water like sugar, salt, and its combination using a wideband CPW fed microstrip antenna with periodic EBG ground structure. The antenna is designed and fabricated to operates at the bandwidth of 3 GHz with a stable gain of 9 dBi maintaining VSWR<2. The uniquely designed antenna works as a sensor in its near field to sense the solvents in water in terms of resonant frequency and reflection method in wider bandwidth. The technique also detects the changes in the temperature of the soft drinks as a function of reflection characteristics. This technique will be useful for finding the percentage of solvents in soft drinks before consumption. The sensing technique is without physical contact with the solution and chemical process. Therefore it is a healthy way to find the ingredients in solutions like soft drinks. The technique will be useful to the food regulation boards to limit the contents of beverages and cold drinks.

Background NOD-like receptor pyrin 7 (NLRP7) has been identified as the major gene responsible for the recurrent hydatidiform mole (RHM). The immunological role of NLRP7 mutation in HM patients has not been conclusively demonstrated. Hence, we aim to demonstrate this role in our study. Methods We followed 12 new patients with NLRP7 nonsynonymous variations (NSVs) from date to date. Peripheral blood mononuclear cells (PBMCs) were collected from patients with and without NLRP7 mutation, separately. Supernatant IL-1β secretion, intracellular pro-IL-1β and mature-IL-1β expressions were measured after 24h lipopolysaccharide (LPS) stimulation. Plasmids with corresponding NSVs were generated to evaluate the ability of processing pro-IL-1β into mature-IL-1β in vitro. Results Homozygous or compound heterozygous NLRP7 mutation secreted less IL-1β in root of abnormal intracellular pro-IL-1β or mature-IL-1β according to different domain defective. Plasmids with NSVs could also affect processing or/and trafficking together with caspase-1 and apoptosis-associated speck-like protein (ASC). Conclusion Inflammasome related NLRP7 mutation is a potential mechanism of RHM.

The set of hybrid numbers is a noncommutative number system unified and generalized the complex, dual and double(hyperbolic) numbers with the relation IH = − HI = ε + I. Two hybrid numbers P and Q are said to be similar if there exist a hybrid number X satisfying the equality X−1QX = P. And it is denoted by p ∼ q. In this paper, we study the concept of similarity for hybrid numbers by solving the linear equations PX = XQ and QX − XP = C for P, Q, C ∈ 𝕂. KEYWORDS : Hybrid numbers, quaternions, coquaternions, dual and double numbers. MSC CLASSIFICATION : 15A66, 11R52, 15A18, 15A06, 16S50.

Programmed to retain active responsivity to environmental stimuli, diverse types of synthetic gels have been attracting interests regarding various applications, such as versatile elastic biodevices. In a different approach, when the gels are made of tissue-derived biopolymers, they can act as an artificial extracellular matrix (ECM) for use as soft implants in regenerative medicine. To explore the physical properties of hydrogels in terms of statistical thermodynamics, the mean-field Flory-Huggins-Rehner theory has long been used with various analytical and numerical modifications. Here we suggest a novel mathematical model on the volume phase transition of a biological hybrid gel that is sensitive to ambient temperature. To mimic acellular soft tissues, the ECM-like hydrogel is modeled as a network of biopolymer chains, such as type I collagen and gelatin, which are covalently crosslinked and swollen in aqueous solvents. Within the network, thermoresponsive synthetic polymer chains are doped by chemical conjugation. Based on the Flory-Huggins-Rehner framework, our model phenomenologically illustrates a well-characterized volume phase behavior of engineered tissue mimics as a function of temperature by formulating the ternary mixing free energy of the polymer-solvent system and by generalizing the elastic free energy term. With this formalism, the decoupling of the Flory-Huggins interaction parameter between the thermoresponsive polymer and ECM biopolymer enables deriving a simple analytical equation for the volume phase transition as a function of the structural and compositional parameters. We show that the doping ratio of the thermoresponsive polymers affects the phase transition temperature of the ECM-like gels.

As digitilisation is being applied in redefining products and business models world-wide, evidence abound in the construction industry as a sector that is slow to its adoption. While digitilisation tools have been applied in modifying processes/procedures in the global North; a larger percentage of the sector in the global South is yet to be disrupted. For indigenous firms to join the rapid transformation wheel, this study reviews the interrelationship between digitilisation and building information modeling. The study objectives are to examine the prevalence of cultural and strategic capability, evaluate the relationship between cultural orientation and strategic capability as well as predict a model of building information adoption from culture and strategy. The study population was drawn from the list of construction firms registered with the Lagos State Tender board, list of registered construction firms from the Institute and specific listed firms on the internet. Factor Analysis, Correlation and Regression were the adopted statistical tools. The results revealed production; task and goal attainment; information/communication technology; workforce; innovation, learning and knowledge management as well as conflict and dispute resolution as the prevalent cultural orientations. The availability of resources to communicate, interact and collaborate digitally and leadership capability to organise and coordinate digitally are the top two strategic capabilities. Consequently, 3 out of every 5 firms have moderate awareness on BIM implementation. It was concluded that the level of agreement on the adoption of the culture and the strategy did not reflect on the level of BIM adoption model. Since the results revealed that the existing orientation and strategy contribute about a tenth of BIM adoption model; the firms’ leadership need cultural re-orientation from the client angle and from business environment. On strategy, the firms need support from institutions/government on policies that will cushion the effect of the provision of resources for transformation.