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The friction coefficient resulting from the road surface condition directly affects the vehicle braking condition and distance. In the American Association of State Highway and Transportation Officials (AASHTO), the braking distance for different speeds, upgrades, and downgrades is recommended. However, the effects of the variations in the friction coefficient, type, and weight of vehicles are not directly taken into account. Therefore, the present study firstly examines the effects of the variations in vehicle speed, friction coefficient, longitudinal grade (upgrade and downgrade) in AASHTO 2018, and the vehicle type on braking distance. Secondly, a nonlinear analytical approach is considered to estimate braking distance and determine a critical friction coefficient that causes decreases in the braking distance. The findings indicate that under dry road surface conditions (with a friction coefficient of 0.6), the weight of the vehicle predominantly influences braking distance, resulting in heavier vehicles having shorter braking distances than lighter vehicles across all selected grades, except at a − 6%. However, when the road surface friction coefficient decreases from 0.6 to 0.18, the impact of vehicle weight surpasses the effect of the longitudinal grade, leading to an increase in braking distance. Consequently, when designing a road, it's essential to consider not only the technical road parameters and vehicle dimensions but also the vehicle weight and the road surface conditions in areas prone to snowfall, among other factors. If we wish to account for snowy and icy conditions, in addition to AASHTO's classification of wet conditions, in order to refine predictions of braking distance, the results of this study can provide valuable insights for road designers. [ABSTRACT FROM AUTHOR]

This paper presents the development of an optimization and modeling method for the objective functions of output power, efficiency and weight of an outer rotor permanent magnet brushless DC (BLDC) motor based on radial basis function (RBF) approximation technique. The proposed RBF‐based Pareto optimization method requires less knowledge about electric/magnetic formulas and can replace conventional optimizations based on these equations with higher accuracy. To apply the proposed optimization method, the initial design should be developed using such equations. Therefore, RBFs are used to model and predict engine behavior. To optimize the objective functions, we used a genetic algorithm optimization technique with nonlinear electric and magnetic constraints to find the Pareto front set. The design obtained by the proposed radial basis function Pareto optimization (RBFPO) method was finally verified by Ansoft Maxwell. The results of optimal design using the RBFPO method have higher output power and efficiency. Also, in addition to the advantage of a favorable accuracy, RBF‐based models are significantly faster than models available in simulation tools. [ABSTRACT FROM AUTHOR]

In this study, dynamic response of functionally graded (FG) nanobeam under a moving load in a thermal environment has been investigated. By considering the size effect, nonlocal Euler–Bernoulli beam theory has been used to model a FG nanobeam. By applying Hamilton's principle, governing equations of motion and boundary conditions, have been derived. Analytical solution by using Laplace transform method has been achieved. Presented results have been verified by comparing with the results found in the literature, which this comparison shows good agreement between them. Influences of the nonlocal parameter, material distribution index, velocity of the moving load, and temperature changes on the response of the FG nanobeam have been investigated. The results show that increasing the nonlocal parameter and temperature changes leads to raising the dynamic deflection of the FG nanobeam. [ABSTRACT FROM AUTHOR]

This paper studied the free vibration behavior of coiled carbon nanotubes (CCNTs) using continuum mechanics methods and molecular dynamics (MD) simulations. Based on the continuum mechanics method, a new elasticity model called the nonlocal generalized Washizu beam (NGWB) was innovated by considering the effects of the curvature and cross-section thickness of nanotubes, as well as size-dependent effect. Then, the governing equations for the vibrational behavior of CCNTs were derived and solved using the numerical generalized differential quadrature method (GDQM). The free vibration behavior of CCNTs was also examined by performing the MD simulations to determine the calibrated values of the nonlocal parameter ( μ) that are applied in the NGWB elasticity model and to validate and evaluate the obtained results. Since the NGWB elasticity model considers the size-dependent effect on the vibrational behavior, obtained results from it well agrees with the MD simulation results in the present study. For CCNTs, there was a coupling between transverse, longitudinal, and torsional vibrations, which led to the beating phenomenon. The natural frequencies decreases by increasing the number of pitches ( n p) , aspect ratio (p / D) , and pitch angle (α ¯). The nonlocal parameter has a more significant effect on the frequencies of CCNTs with smaller geometrical parameters. In addition, the type of boundary conditions affects the calibrated values of the nonlocal parameter, frequency values, and arrangement of vibrating mode shapes of CCNTs. Results of the present study can be applied in the design and analysis of nano-electro-mechanical systems (NEMS), sensors, and nano-composite structures containing CCNTs. Also, the NGWB elasticity model might be useful in the statics and wave propagation studies of CCNTs, and other coiled and curved nano-structures. [ABSTRACT FROM AUTHOR]

Vehicle traffic flow channelizing can significantly contribute to fewer collisions and smooth traffic flow in isolated signalized intersection design. Therefore, this study investigates the effect of changes in the number of right-turn lanes with splitter islands and left-turn storage bays for different volume approaches on intersection performance. This study aims to provide an accurate analysis to estimate the effect of such changes on signalized intersections, which can improve intersection performance. Furthermore, the delay parameter derived from HCM2016 and simulation was evaluated for different scenarios. For this purpose, simulation was performed using Synchro software. In this study, a symmetrical, 90-degree, undersaturated (volume per capacity lower than 1, V/C < 1), and four-leg intersection were considered according to AASHTO Green Book 2018 suggestions. HCM2016 results indicated the delay parameter was less sensitive to the undersaturated condition than the right-turn volume variation for both single and dual-lane bays. However, the simulation results indicated that the delay parameter was not constant, depending on the number of right-turn lanes and volumes. On the other hand, there was a significant difference in delay parameters between the single and dual left-turn lanes for both simulation and HCM cases estimated 77.4% and 59.7%, respectively. Overall, this study can provide a vision for traffic engineers to modify the geometry of the four-leg signalized intersections, if the right-turn or left-turn demand volume of an undersaturated signalized intersection is larger than the through approach. [ABSTRACT FROM AUTHOR]

In this study, a framework for statistical design of a brushless DC (BLDC) motor is proposed in order to maximise yield while keeping efficiency as high as possible and the non‐linear constraints, that is, limitations of flux density, current density and physical dimensions, satisfied. The proposed yield maximisation method has two major steps: polyhedral approximation of the constraint region and yield maximisation. By implementing the proposed method, the optimum design parameters, that is, embrace, thickness and length of magnet, are obtained with maximum immunity to variations in magnet dimensions. Also, highly accurate artificial neural network‐based models are used to estimate the objective function and constraints. It is also shown that by adjusting performance constraints (efficiency and flux density), different design goals can be achieved which help to choose the appropriate design according to the designer's goals. [ABSTRACT FROM AUTHOR]

Here, the authors present a new constrained multi‐objective optimization method for maximizing output power and efficiency of switched reluctance motor (SRM). The constraints play a significant role in this process. Artificial neural network‐based models are created to represent the SRM behaviour which is a difficult task. For this reason, a single neural network for each objective is built and the number of training data has been increased to reach a good accuracy. The authors propose a neural network‐based adjoint Lp metric technique to combine several objective functions and constraints with different weight factors to a single function which should be minimized. To apply the constraints, an adjoint term is added to the original Lp function including only objective functions. The flux densities of the magnetic materials are selected as the optimization constraints. When approaching as close as possible to the saturation level, the SRM has a better performance. Adding an adjoint term to the original Lp leads to better optimization results which were proved by comparing with a conventional optimization. Also, all obtained results were finally validated by the Ansoft Maxwell software. [ABSTRACT FROM AUTHOR]

This study presents a new method for parametric modelling and optimisation of a permanent‐magnet brushless DC (BLDC) motor. We proposed an artificial neural network (ANN)‐based LP metric technique to combine and optimise different objective functions of a BLDC motor using ANN‐based models and compared with conventional optimisation methods with analytical models. To proceed with this optimisation problem, the LP function should be minimised. For applying constraints to this problem, a simple method called penalty factor is proposed, in which a penalty term was added to the LP function when the constraints are violated. We considered three goals in this optimisation: efficiency maximisation, speed maximisation and material cost minimisation. Since the load is constant torque in our case, more speed means more powerful motor, and to achieve the minimum material cost goal the volume of the magnet is set as an objective function. To find the optimum geometric parameters, we used gradient‐based method subject to non‐linear magnetic constraints. All the obtained results were validated by Ansoft Maxwell. Optimising using the proposed method including ANN‐based models does not require knowledge about complicated electric/magnetic equations. Also, ANN‐based BLDC motor model is more accurate than analytical models and faster than existing models in simulation tools. [ABSTRACT FROM AUTHOR]

• A new biological layer detection strategy based on nonlinear vibration is proposed. • Vibration of Piezoelectrically driven biosensor is studied via couple stress theory. • Biological layer absorption effect on the sensor size-dependent frequency is studied. • By studying the half-stable region, the jump phenomenon in amplitude is investigated. In this paper, the nonlinear forced vibration of a piezoelectrically driven micro/nano cantilever-based biosensor is investigated via couple stress theory. The origin of nonlinear equations is the curvature, which causes cubic nonlinearities in the differential equation. Due to the dimensions of the structure and its size-dependent behavior, the governing equation is derived based on couple stress theory. In order to obtain the frequency-response equation, the differential equation is solved with the assumption of small displacement, damping coefficient, and excitation amplitude by the multiple scales method. Then, the amplitude of the response and the nonlinear resonance frequency based on the classical and couple stress theory are presented and the effect of the absorption of the biological layer on the frequency variation of the two theories is compared with each other. Also, to achieve high sensitivity resulting from optimal dimensions, the variation of beam frequency for various dimensions has been studied. Finally, by studying the bifurcation points and half-stable region, the jump phenomenon in amplitude caused by biologic layer absorption as a strategy for biological detection has been investigated and the results validated qualitatively with previous studies. [ABSTRACT FROM AUTHOR]

In this paper, thermoelectric-mechanical buckling behavior of the piezoelectric nanobeams is investigated based on the nonlocal theory and Euler-Bernoulli beam theory. The electric potential is assumed linear through the thickness of the nanobeam and the governing equations are derived by Hamilton's principle. The governing equations are solved analytically for different boundary conditions. The effects of the nonlocal parameter, temperature change, and external electric voltage on the critical buckling load of the piezoelectric nanobeams are discussed in detail. This study should be useful for the design of piezoelectric nanodevices. [ABSTRACT FROM AUTHOR]

• The residual tensile strength after impact of glass/polyester laminates is investigated. • Damage areas are detected by using visually inspection. • Residual tensile strength of samples impacted by hemispherical tip is estimated using two fracture mechanics models. • The residual tensile strength for the damaged laminates is predicted using new model. • The proposed model predicts the residual strength with much higher accuracy and much less error than the existing models. In this study, the residual strength of the post impacted glass/polyester laminates is investigated by the conduction of tension after impact (TAI) loading. The specimens are placed on a rigid plane and subjected to low velocity impact using a drop weight impact tower. Damage areas are detected by using visually inspection and measuring the size of the permanent impression on the surface of specimens. The relationships between the impact energy and degradation of mechanical properties have been stablished for the composites. The residual tensile strength for the impact-damaged laminates is predicted using new model. The correlation between the experimental and new model results is found to be good. Two models proposed by Caprino and Koo have been using to compare the results. [ABSTRACT FROM AUTHOR]

Glass-fiber-reinforced aluminum layers (GLARE) are one of the excellent impact resistant materials, benefited from both the metal and glass fibers properties. Owing to their high impact damping properties, the shape memory alloys have been also considered as useful materials for arming the conventional impact-exposed materials. In the present paper, the shape memory wires were integrated with GLARE laminate and its response to the Charpy low-velocity impact was experimentally studied. The current study is aimed to determine the effects of three parameters (pre-strain percentage of shape memory alloy (SMA), glass fibers angle and the location of SMA wires within the novel fiber metal laminate) for the first time. Hybrid GLARE specimens of this study were planned by Taguchi design of experiments (DOE) method and contained Nitinol shape memory alloy wires. The results showed that the pre-strain and the angle of glass fibers are the most effective parameters on the impact energy absorption at accepted levels of confidence. Regarding the innovations in the construction of this type of impact-resistant hybrid composites, this study could be used in design of aerospace bodies. [ABSTRACT FROM AUTHOR]

Objective: To investigate the frequency of hemophagocytic syndrome in a series of patients with otherwise unexplained cytopenia. Material and Method: In this cross-sectional, single-centre study, bone marrow specimens (n=288) were obtained from the patients with unexplained cytopenia. The diagnosis of hemophagocytic syndrome was made according to universally accepted criteria. Characteristics of the patients, as well as the clinical and laboratory findings were reported. Results: Fifteen cases (5.2%) fulfilled the hemophagocytic syndrome criteria, including 8 males (53.3%) and 7 females (46.7%) with a mean age of 39.7±20.7 (range: 14-72) years at the time of diagnosis. The main clinical and laboratory findings were cytopenia (100%), fever (73.3%), hyperferritinemia (66.7%), elevated erythrocyte sedimentation rate (60%), hypertriglyceridemia (60%), organomegaly (53.3%), elevated liver enzymes (53.3%), lymphadenopathy (26.7%), neurological symptoms (20%), and skin rash (13.3%). Two patients (13.3%) died before a diagnosis was made. Conclusion: Our findings indicate that the hemophagocytic syndrome is not a rare pathologic condition in patients with otherwise unexplained cytopenia. Without treatment, the mortality rate may be high. [ABSTRACT FROM AUTHOR]

Examines the use of magnetic resonance imaging and venography in the evaluation of patients with May-Thurner syndrome in Hartford, Connecticut. Evaluation of suprainguinal deep venous thrombosis and pelvic mass; Anatomic characteristics of May-Thurner syndrome; Treatment of patients.

The aim of this research is to investigate the thickness influence on the efficiency of multiwalled carbon nanotubes (MWCNTs) in glass/epoxy composite laminates under the high‐velocity impact. Combining 0.25 wt% of MWCNTs in the 4‐layer and 8‐layer specimens and 0.1 wt% of MWCNTs in the 16‐layer specimen led to the maximum rise in the energy absorption and specific perforation energy compared with the unreinforced laminates. The significant growth in energy absorption in the 4‐layer, 8‐layer, and 16‐layer specimens was 5.8, 8.3, and 14.4 J, respectively. The number of agglomerations (dislocations) in the matrix was consequently increased as a function of thickness, which led to the better performance of MWCNTs with lower weight percentages in the composite laminates containing more layers. The scanning electron microscope was used to observe the dispersion and agglomeration of MWCNTs in the resin epoxy, and there was also an improvement in the fiber–resin bonding. [ABSTRACT FROM AUTHOR]

Two-way two-lane roads have a significant impact on road transportation infrastructure. Platoon formation on two-lane roads is one of the factors that affect the quality of traffic flow on two-lane roads. More specifically, the creation of a platoon increases the density of vehicles and the number of overtaking maneuvers and decreases the traffic performance of two-lane roads. The present study made an effort to investigate the effect of the platoon characteristics on the traffic flow of vehicles on two-lane roads. Moreover, it strived to develop the nonlinear regression model with a new approach to capacity calculation. Finally, a method for estimating the level of service (LOS) based on the number of followers per capacity (NFPC) and LOS classification using the KNN method was presented. Considering these aims, first, the relevant variables (which were related to platoon) including time headway (Ht), average travel speed (ATS), platoon size (PS), average platoon speed (APS), percentage of heavy vehicles (HV), percent time spent following (PTSF), number of overtaking (NO), density (ρ), and traffic flow were investigated on the examined roads. The results showed that the speed and the Ht were the most effective and the least effective platoon characteristics, respectively. Moreover, it was accompanied by the increase in PTSF which resulted in the increase in overtaking maneuver. Finally, the results regarding the developed model showed that the NFPC measure was able to predict the traffic flow of two-lane roads in a more satisfactory way compared to the two criteria, namely, PTSF and ATS in the Highway Capacity Manual (2016) since it increased ATS by 65% and decreased the capacity of two-lane roads by 21%. [ABSTRACT FROM AUTHOR]

The static and dynamic behavior of a curved single-walled carbon nanotube which is under twist-bending couple based on nonlocal theory is analyzed. The nonlocal theory is used to model the mechanical behavior of structure in small scale. The obtained differential equations are solved using a simply supported boundary condition and Navier analytical method. Moreover the twisted vibration and bending of curved nanotube is analyzed and also the armchair model is assumed in this study. The following parameters were studied in this paper: the effect of nonlocal parameter, the curved nanotube's opening angel, the Young's modulus and the mode number is studied. The results were verified with the previous literature which showed an excellent agreement. The results of this paper can be used as a benchmark for future investigations. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the frequency of different histopathological findings obtained from dilatation and curettage (D&C) specimens in patients with abnormal uterine bleeding (AUB). Methods: In a retrospective review of 591 specimens, the included subjects were all women with AUB who underwent D&C between 2002 and 2006 in Be'sat Hospital, Tehran, Iran. The pathological diagnoses were analyzed in four groups from normal to malignant endometrium. The pathological groups were evaluated for patients' characteristics including demographic data and medical history. Results: The majority of patients (61.6 %) were in the 41-50 year age group. Totally, 81.4 % of patients had normal pathology. The disordered proliferative endometrium/polyps, hyperplasia, and malignant pathology were found in 15.4, 2.5, and 0.7 % of specimens, respectively. The abnormal pathologies were seen more among patients with postmenopausal status, nulli-/primigravid women, and those with hypertension, diabetes, hypothyroidism, and polycystic ovary syndrome. Conclusions: The proliferative endometrium and secretory endometrium were the most common histopathological observations in AUB patients in our region, and except normal endometrium, disordered proliferative endometrium was the most common cause of AUB. [ABSTRACT FROM AUTHOR]

Lymphomatous involvement of the appendix is rare and most of them are found accidentally from appendectomies to treat appendicitis. Here we report three cases of primary lymphoma of appendix of 10 year-old boy, 23-year-old man and 24-year-old woman that presented with abdominal pain to our hospital and the tumors were discovered during routine appendectomy for suspected "appendicitis". Our cases underwent chemotherapy regimen and they were asymptomatic respectively at 14, 17, and 18 months following-up. In the literature review of the tumors of the appendix, most of the begin tumors of appendix are treated with surgery alone. Lymphoma requires CHOP-like chemotherapy and carcinoid tumor treated according to the size of the tumor <2 with appendectomy alone and >2 with right hemicolectomy. The preferred treatment for adenocarcinoma of appendix is right hemicolectomy and the role of chemotherapy is unclear but when lymph node involvement is present, chemotherapy seems to be accepted. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma (RCC) represents, on average, over 90% of all malignancies of the kidney that occur in adults in both sexes. Chemokine receptors expression has been found in many kinds of cancer and at tumor metastasis site. We determined CXCR2 and CXCR3 expression in RCC by immunohistochemistry method and analyzed the prognostic value of these markers. Our finding demonstrated that CXCR3 were highly overexpressed in renal cancer tissues compared with those adjacent normal kidney tissues ( P < 0.001). The results showed that high expression of CXCR3 was markedly correlated with metastasis ( P = 0.021) and tumor stage ( P = 0.031). CXCR2 were overexpressed in renal cancer tissues compared with those adjacent normal kidney tissues ( P < 0.001). Our result showed that CXCR2 expression was correlated with high grade ( P = 0.024), advanced stage ( P = 0.029) and metastasis ( P = 0.018). The log-rank test revealed that high CXCR2 and CXCR3 expressions are related to poorer overall survival ( P < 0.001; P < 0.001). In conclusion, this study indicates the correlation of CXCR3 and CXCR3 with progression of RCC. In addition, high CXCR3 andCXCR2 expressions were correlated with shorter overall survival. © 2016 IUBMB Life, 68(8):629-633, 2016 [ABSTRACT FROM AUTHOR]

Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. Reverse anionic flotation by using sodium silicate (SS) as an iron oxide depressant is one of the techniques for iron ore processing. This investigation is going to present a synthesized reagent "sodium co-silicate (SCS)" for hematite depression through a reverse anionic flotation. The main hypothesis is the selective depression of hematite and, simultaneously, modification of the pulp pH by SCS. Various flotation experiments, including micro-flotation, and batch flotation of laboratory and industrial scales, were conducted in order to compare the depression selectivity of SS versus SCS. Outcomes of flotation tests at the different flotation scales demonstrated that hematite depression by SCS is around 3.3% higher than by SS. Based on flotation experiment outcomes, it was concluded that SCS can modify the pH of the process at ~9.5, and the plant reagents (including NaOH, Na2CO3, and SS gel) can be replaced by just SCS, which can also lead to a higher efficiency in the plant. [ABSTRACT FROM AUTHOR]