Here, the eligibility of silicone rubber‐nanoceramic composites as flexible substrates for sub‐6 GHz 5G antennas is investigated. Two different composites are prepared using the solution mixing method, namely mono and hybrid composites. The reflection and transmission coefficient (S‐parameters) of composites are measured using a rectangular waveguide‐based transmission line technique in conjunction with a Vector Network Analyzer (VNA) at C‐band frequencies (4–8 GHz). The Nicolson–Ross–Weir (NRW) algorithm is adopted to extract the complex permittivity and loss tangent of the material under test. Due to the synergetic effect, the silicone rubber hybrid composite (0.12BiVO4+0.12LaNbO4) exhibits the advantage of a lowered loss tangent while retaining a good dielectric constant at 5.78 GHz. A rectangular microstrip patch antenna is designed and simulated with CST software using 0.12BVO/0.12LNO/0.76SR composite as a substrate. Moreover, based on the simulation, the antenna with the proposed substrate has acceptable performance at 5.78 GHz with the return loss, directivity, and gain of −25.05 dB, 5.46 dBi and 2.74 dBi, respectively. As a result, the composite material's ability to act as a suitable substrate for a 5 GHz Wi‐Fi antenna is confirmed.
Shallow foundations are usually built above the groundwater table. In such cases, this soil is considered dry in analysis and design, while it is actually an unsaturated soil. This unsaturated soil can lead to many geotechnical issues, such as swelling when wet and collapsing when dry. It can also change the soil's shear strength, which in turn affects the bearing capacity of the soil. The classical principles of saturated soil are often not suitable for explaining these phenomena. Limited studies dealt with a large scale model close to the field conditions for such soil and therefore, there is much more room for improvement. The study reveals that compacting the expansive soil on the wet side of optimum is capable of reducing swelling pressure and the expansion index for both the bentonite-sand mixture and kaolin soil. The bearing capacity of a footing resting on both swelling and non-swelling soils decreases noticeably with the increase in the soil degree of saturation due to the effect of matric suction which increases the soil stiffness. The results show that the measured bearing capacity is (1.1-3.3) higher than that estimated by Terzaghi equations.
The effect of low-temperature aging treatment on the phase transformation and microstructure on the Ti-rich NiTi shape memory alloys. The recycled Ti wires are used to produce an alloy with a composition (49.9% at. Ni, and 50.1% at. Ti). The VIM method is used to manufacture the NiTi SMA. The samples aged at different temperatures after the solution heat treatment at 850 °C for 15 min. The results show that all samples undergo a one-step transformation during the cooling and heating processes. Increasing the As and Af of samples aged at 350 °C, and 450 °C, while decreasing the As and Af temperatures of the sample aged at 550 °C, compared with a solution-treated sample. The microstructure of all SMAs samples contains the Ti2Ni phase and increases its amount with increasing aging temperatures.
It is known to researchers in the field of road construction and development. Three types of pavement are rigid, flexible, and composite paving. The composite pavement consists of a layer of flexible pavement on top of which a layer of rigid pavement is placed or vice versa. All of these types have advantages in addition to disadvantages that affect road performance on the one hand and user convenience on the other. About 50 years ago, work began establishing a type of pavement characterized by its semi-flexible performance, which combines rigid pavement's rigidity and flexible pavement's flexibility. It is called semi-flexible pavement and grouted macadam in some sources. It consists mainly of an open-graded asphalt mixture in which the percentage of air voids ranges from (25 to 35%), and in some sources, it is mentioned that it ranges between (20 to 28%) grouted with a high-performance cementitious material. Work began on this type of pavement in the sixties of the last century. However, there is no approved specification for its design, as its design methods differ according to the researcher's vision. This scientific paper aims to facilitate the way for new researchers in this field by knowing the basic stages of semi-flexible pavement design and presenting the existing design methods and what is required for laboratory tests to evaluate the performance of the completed pavement design. It was found that the performance of semi-flexible paving depends mainly on the bonding between its components, as it is considered a composite material. For this reason, the direction in the future may be to study the bonding between asphalt and cement, in particular, as they are two basic materials in their composition.
This study investigated the effect of reducing seepage under a hydraulic structure. This article aims to find positional equations for the control devices that reduce the seepage under the hydraulic structure. Using lengths and angles of sheet-piles under the hydraulic structure where the sheet-pile was placed up- and downstream, respectively, upon the hydraulic structure with anisotropy soil hypothetically affects both uplift pressure and seepage values. The experiments were conducted in two cases: in the first case, a couple of sheet-piles were oriented to the upstream passage; while in the second case, they were oriented to the downstream. Then, the second case was compared with three sheet-piles placed upstream, downstream, and intermediate to the passage. For each experiment (at the hydraulic toe position), the major affecting parameters such as the uplift pressure, gradient exit, and outlet flow rate were found. A correlation equation to correlate the exit gradient and discharge parameters was developed.
In this work, gallium nitride (GaN) thin film was deposited on porous silicon (PSi) substrate via a pulsed laser deposition route with a 355 nm laser wavelength, 900 mJ of laser energy, and various substrate temperatures raging from 200 to 400 °C. The structural and optical properties of GaN films as a function of substrate temperature are investigate. XRD studies reveal that the GaN films deposited on porous silicon are nanocrystalline with a hexagonal wurtzite structure along (002) plane. The photoluminescence emission peaks of the GaN/PSi prepared at 300 °C substrate temperature are located at 368 nm and 728 nm corresponding to energy gap of 3.36 eV and 1.7 eV, respectively. The GaN/PSi heterojunction photodetector prepared at 300 °C exhibits the maximum performance, with a responsivity of 29.03 AW ⁻¹ , detectivity of 8.6 × 10 ¹² Jones, and an external quantum efficiency of 97.2% at 370 nm. Similarly, at 575 nm, the responsivity is 19.86 AW ⁻¹ , detectivity is 8.9 × 10 ¹² Jones, and the external quantum efficiency is 50.89%. Furthermore, the photodetector prepared at a temperature of 300 °C demonstrates a switching characteristic where the rise time and fall time are measured to be 363 and 711 μs, respectively.
Three samples of Fe−S were prepared with different hydrothermal periods (6, 12, and 18 h). X‐ray diffraction (XRD) test showed that the first produced sample contained 42.3 wt % of magnetite, 35 wt % of greigite, and 22.7 wt % of pyrite phases. The same phases were formed during the second period but with different wt % ratios. The greigite increased to 67.8 wt % by the third period, while the magnetite and pyrite phases vanished and were associated with a low ratio of the presence of pyrrhotite and FeO 2 . Scanning electron microscope (SEM) images confirmed the formation of the nanoparticles. The increase in the hydrothermal time produced a reduction in the saturation magnetization (39.8 to 9.1) emu/g and the remanence magnetization (8 to 2.4) emu/g, and increasing in the coercivity. To assess the viability of Michigan Cancer Foundation‐7 (MCF‐7) and hemolytic disease of the fetus and newborn (HdFn) cells, a colorimetric assay for assessing cell metabolic activity (MTT) was applied to the third sample. The outcome verified iron sulfide‘s cytocompatibility against HdFn cells even at high concentrations and good anticancer activity against MCF‐7 cell lines. The result of the DPPH test confirmed that the third sample had antioxidant activity equivalent to that of ascorbic acid.
Cancer is a multifaceted and complex disorder characterized by uncontrolled rates of cell proliferation and its ability to spread and attack other organs. Emerging data indicated several pathways and molecular targets are engaged in cancer progression. Among them, the Wnt signaling pathway was shown to have a crucial role in cancer onset and progression. Dishevelled (DVL) acts in a branch point of canonical and non-canonical Wnt pathway. DVL not only acts in the cytoplasm to inactivate the destruction complex of β-catenin but is also transported into the nucleus to affect the transcription of target genes. Available data revealed that the expression levels of DVL increased in cell and clinical specimens of various cancers, proposing that it may have an oncogenic role. DVL promoted cell invasion, migration, cell cycle, survival, proliferation, 3D-spheroid formation, stemness, and epithelial mesenchymal transition (EMT) and it suppressed cell apoptosis. The higher levels of DVL is associated with the clinicopathological characteristic of cancer-affected patients, including lymph node metastasis, tumor grade, histological type, and age. In addition, the higher levels of DVL could be a promising diagnostic and prognostic biomarker in cancer as well as it could be a mediator in cancer chemoresistance to Methotrexate, paclitaxel, and 5-fluorouracil. This study aimed to investigate the underlying molecular mechanism of DVL in cancer pathogenesis as well as to explore its importance in cancer diagnosis and prognosis as well as its role as a mediator in cancer chemotherapy.
Designing a reliable routing protocol for Vehicular Ad hoc Network (VANET) poses considerable challenges due to certain unique challenges inherently present in Vehicular Ad hoc Network (VANET) topology. Some of them are needed for vehicles acting as nodes having to abide by traffic rules, uncertain inter-vehicular speed variations that may affect link stability etc. Designing a routing protocol capable of dealing with multiple limiting conditions such as long congestion periods, link failures and handoffs is a challenging task, where most of the existing multipath routing protocol shows poor performance. In this paper, the proposed Multipath Route Restoration Protocol (MRRP)is aimed at providing a robust communication channel in case of link failure between nodes. This is realized by focusing on better route maintenance for the protocol. In a wireless network, a routing protocol determines the particular ways in which routers connect. In a wireless network, as the number of hops in a wireless communication path increases, various signal factors such as interference and path loss degrade the network performance. however, sending data over a longer distance will reduce throughput. Furthermore, link stability is substantially impacted by the unpredictable movement of vehicles. Multipath routing is regarded as a potential solution to improve packet delivery and end-to-end delay in VANETs.
Recently, engine design and control systems have been developed using data-driven modeling techniques to specify the in-cylinder complicated combustion process. The cooling fan performance is highly influenced by several factors that are determined based on what is called (DOE) «design of experiments». These factors include blade tip clearance, pitch angle, and distance from a radiator. This work presents a method to improve the cooling fan performance of an engine by designing a Six Sigma technique using Control, Improve, Analyze, Measure, and Define (CIAMD). First, let's assess the existing cooling fan performance and define its problem. Then, let's specify the parameters that affect fan performance to be optimized. Next, let's conduct a sensitivity analysis and evaluate the manufacturing control of the developed cool Fan. The primary fan does not distribute air enough by the radiator to keep the machine cool throughout hard circumstances. First, the work demonstrates how to develop an experiment to examine the influence of three performance elements: blade pitch angle, blade-tip clearance, and fan distance from the radiator. In order to improve the performance of the cooling fan, the Box-Behnken design is adopted for testing quadratic (non-linear) effects. It then indicates how to predict optimal quantities for every element, to produce a technique that makes airflows above the objective of 1486.6 m 3 /h when utilizing experimental measurements. Finally, it reveals how to operate simulations to confirm that this method creates airflow based on the specifications with more additional fans manufactured performance of 99.999 %. The results of S and X-bar control charts indicate that the manufacturing process is statistically under control
This systematic review and meta-analysis aimed to evaluate the relationship between body mass index (BMI) and mortality of burn patients. A comprehensive, systematic search was conducted in different international electronic databases, such as Scopus, PubMed, Web of Science and Persian electronic databases such as Iranmedex, and Scientific Information Database (SID) using keywords extracted from Medical Subject Headings such as "Body mass index", "Burns" and "Mortality" from the earliest to the April 1, 2023. The quality of the studies included in this systematic review was evaluated using the appraisal tool for cross-sectional studies (AXIS tool). Finally, six articles were included in this systematic review and meta-analysis. A total of 16 154 burn patients participated in six studies. Their mean age was 46.32 (SD = 1.99). Of the participants, 71.7% were males. The mean length of hospitalization was 18.80 (SD = 8.08) days, and the average TBSA in burn patients was 38.32 (SD = 2.79) %. Also, the average BMI in burn patients was 27.10 (SD = 1.75). Results found mortality in patients with abnormal BMI (overweight to morbidity BMI) was 0.19 more than normal BMI (ES: 1.19, 95%CI: 0.76-1.87, Z = 0.75, I2 : 71.8%, p = 0.45). Results of linear dose-response showed each 5 kg/m2 increase in BMI was associated with a 5% increase in mortality that was marginally significant (ES: 1.05, 95%CI: 1.00-1.11, Z = 1.99, I2 : 22.2%, p = 0.047). There was a non-linear relationship between levels of BMI and mortality (Prob > χ2 = 0.02). There was an increase in mortality from percentile 10 to 50, although it was not significant (Correlational coefficient: 0.01, p = 0.85). Also, there was an increase in mortality rate from percentile 50 to 90 that was statistically significant (correlational coefficient: 0.06, p = 0.047). Finally, the results of the study indicated BMI can increase the chance of mortality by 0.19, although it was not significant. As a result, more studies are needed to better judge the relationship between BMI and mortality in burn victims.
In recent years, the alarming spread of antibiotic resistance has posed a grave global threat to public health, resulting in millions of fatalities worldwide. Multidrug-resistant (MDR) microorganisms have emerged due to the broad spread of resistance and the sharing of resistance genes between various varieties of bacteria. A promising strategy for treating difficult-to-treat bacterial infections is the development of nanomaterial-based therapeutics that could circumvent existing pathways linked to acquire drug resistance. The objectives of this study were to prepare chitosan/pectin-encapsulated Echinacea pallida (E. pallida) extract and evaluate its efficacy against MDR isolates. E. pallida extract was encapsulated into chitosan (CS)/pectin (PN) nanoparticles (NPs) using the gelation technique in the present study. The synthesized NPs were analyzed using scanning electron microscopy (SEM), dynamic light scattering (DLS), transmission electron microscopes (TEM), and Fourier transform infrared (FT-IR) spectroscopy. Antibacterial and antibiofilm activity of the nanoparticles against S. aureus has been assessed and explored. In addition, the toxicity of synthetic NPs against HEK 93 cells was evaluated. The interactions between functional groups were confirmed by FT-IR spectroscopy. The CS/PN NPs were spherical with uniform surfaces, and their dimension ranged from 80 to 110 nm. The PDI of the E. pallida extract was 0.521, and its entrapment efficiency (EE%) was 84.35%. The synthesized CS/PN NPs exhibited antibacterial and antibiofilm activity against bacteria relevant to public health. In addition, the results demonstrated that the extract-containing NPs had no toxic impact on HEK-93 cells. The findings presented here should aid the development of novel plant extracts with enhanced stability and antibacterial activity, thereby reducing the need for antibiotics.
This study presents an experimental measurements and three-dimensional simulation of time-varying scour, along with the variables affecting the resulted scour hole dimensions and evolution at center and side weirs. Slit weir location, crest level, flow rate and sediment size were tested within 34 steady and unsteady flow conditions under various flow rates 125, 95, 62, 50 and 34 L/s to study the scour behavior. All tests were carried out with non-uniform sediments of median sizes 0.24 mm and 0.55 mm. Steel slit weirs of 0.25 m width, 0.004 m thickness, and 0.07, 0.12 and 0.17 m crest level with respect to the mobile bed surface, which was constructed in a laboratory flume made up of brick and concrete within dimensions of (8 m, 1.25 m, and 1 m) long, wide and deep respectively. The present research demonstrates that maximum values of scour volume and scour depth obtained when the weir locate at center of the flume with flat crest for both steady and unsteady flow. Besides, the results indicated a low discrepancy between the experimental measures and the sediment scour model FLOW 3D software, both are showed a good agreement in presenting the scour development accurately as well as the model had excellent ability in predicting the velocity magnitudes at the slit location and the values of shear stress which was hard to measure directly.
This study investigates the reaction pathways and kinetics to comprehend the catalytic cracking of dodecane, a heavy naphtha model compound, over the nanocrystalline ZSM-5 catalyst in the presence and absence of steam with the aim of increasing olefin production. The nanocrystalline zeolite was characterized using XRD and BET, and the surface acidity was measured by NH3-TPD and Py-FTIR. The steam treated ZSM-5 contributed to an increase in pore volume with extra-framework alumina, resulting in highly catalytic active sites and hence higher olefin selectivity. The high conversion of dodecane (>90%) was achieved during catalytic cracking in the presence and absence of steam. In the presence of steam, the short pores of nano ZSM-5 led to an increase in the naphtha-to-olefin conversion with lesser dry gas and coke formation. The activation energies of primary cracking in the presence and absence of steam were slightly different. Lower activation energies through secondary cracking routes and higher reaction rate constants were obtained via assisted-steam catalytic cracking, promoted the selectivity towards light olefin products. Meanwhile the hydrogenation and alkylation reactions toward LPG and C5+ were favored in the absence of steam. Moreover, the ZSM-5 nano zeolite pores promoted more β-scission reactions, resulting in higher selectivity towards ethylene and dry gas.
Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease. One of the biggest concerns within gene-based therapy is the delivery of the therapeutic microRNAs to the intended place, which is obligated to surpass the biological barriers without undergoing degradation in the bloodstream or renal excretion. Hence, the delivery of modified and unmodified miRNA molecules using excellent vehicles is required. In this light, mesenchymal stem cells (MSCs) have attracted increasing attention. The MSCs can be genetically modified to express or overexpress a particular microRNA aimed with promote neurogenesis and neuropro-tection. The current review has focused on the therapeutic capabilities of microRNAs-overexpressing MSCs to ameliorate functional deficits in neurological conditions. K E Y W O R D S gene therapy, mesenchymal stem cell (MSC), miRNA, neurogenesis, neurological diseases
A modified photonic crystal fiber (PCF) was utilized as a biosensor, incorporating gold nanoparticles as an active plasmonic material. The finite element method (FEM) was employed to compute numerical interpretations of sensing performance using various liquids: liver blood, colon blood, human plasma, water, and pentanol. In the proposed biosensor configuration, the test sample (analyte) was placed within the core, surrounded by cladding air holes, and external to the hollow core fiber structure. Sensitivity calculations were conducted both before and after the addition of the gold overlayer. The maximum amplitude sensitivity was determined to be 769.57 RIU⁻¹ for human plasma, accompanied by the optimal electric field of 400V/m. Similarly, in the same liquid, when the deposited photonic crystal fiber (PCF) was coated with a gold layer, the maximum amplitude sensitivity reached 975.53 RIU⁻¹ at an optimal electric field of 477 V/m. Considering the proposed sensor as a refractive index sensor, it exclusively utilized an analyte sample within the core and air holes of the PCF. Here, the maximum amplitude sensitivity attained was 869.84 RIU⁻¹, aligning with the best electric field value of 434 V/m."
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