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Objectives: Workplace safety is essential to occupational health practices among healthcare providers, especially for nurses vulnerable to work-related hazards such as needle stick and sharp injuries. In Yemen, the underestimation and absence of reporting system and lack of health supplies in a collapsed health system exacerbated the needle stick and sharp injuries. This study aimed to identify the prevalence and associated factors of needle stick and sharp injuries among nurses in Taiz, Yemen. Methods: A cross-sectional study was conducted on a sample of 151 nurses working in three public hospitals in Taiz City. A semi-structured questionnaire was designed and delivered to the participants. Results: The prevalence of needle stick and sharp injuries among nurses was very high (95.36%), and around half were injured more than five times. Female nurses and those in an emergency department were more likely to be subjected to needle stick and sharp injuries ( p = 0.018 and 0.021, respectively). Needle stick was the most common cause of injury (62.77%), and the fingers were the most exposed injury site (79.17%). Non-reporting injuries were very high (73.61%), and only one-third (34.21%) of them proceeded in the process of management, and less than one-quarter (23.68%) had been vaccinated. Conclusion: The prevalence of needle stick and sharp injuries among nurses in Taiz was very high, and determined by gender and place of work. Post-injury reporting and precautions were poor, which may increase the prevalence of hospital-acquired infections among clients and healthcare providers.

Objective. This study aims to highlight the low birth weight (LBW) in Taiz City (Yemen), as LBW is one of the public health challenges experiencing a profound effect on newborns. Methods. This was a cross-sectional study since the interview and medical records were the sources of data to be analyzed by SPSS. Results. The findings of this study include; a high prevalence of LBW (39.11%), the maternal age was not associated with LBW ( P = .68), and education level, economic status, residence place, and health status were not associated with LBW ( P

In this research, a novel spinel architecture of pure CdAl2O4 and Zn (0.025–0.075 M) doped CdAl2O4 nanoparticles were synthesized. The PL and ESR outcomes shows that the Zn doping played an effective role to prevent the e−-h+ pairs recombination in CdAl2O4 during photocatalysis. Zn (0.075 M)-CdAl2O4 provided the maximum photodegradation efficiencies for BB and BG with a removal efficiency of 91 and 96% in just 90 min as compared to other samples and remain stable after the fifth cycle. Such outcomes pave the approach for sustainable photocatalytic technologies to diminish the global influence of organic and inorganic dyes.

Abstract With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel (CA) with highly enhanced thermal conductivity (TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires (SiC NWs)/boron nitride (BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m−1 K−1 at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy (EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 1011 Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of − 21.5 dB and a wide effective absorption bandwidth (

Background: The use of renewable energies is extended due to their valuable features such as abundant and clarity. The microgrids that include the renewable energies are widely used in various applications such as power supplying of remote areas, increasing the network reliability, reducing the greenhouse gas emission, reducing the consumption demand, eliminating the consumption peaks, and so on. But, energy management in the these systems in an challenging problem. Because, there are some natural perturbations such as variation output load, grid-side faults and changes of irradiation and temperature. Aim and Objective: The problem is to design a controller to regulate the output voltage/energy under aforementioned disturbances. Methods: The paper presents a new approach for energy management in Photovoltaic (PV)/Battery/Fuel Cells (FC) systems. The uncertainties are compensated by the new optimization rules based on Immersion and Invariance (I&I) theorem and proposed deep learning type-2 fuzzy logic compensator (T2FLC). The objective function of T2FLC is to minimize the tracking error in presence of perturbations. The adaptation rules are derived such that the I&I stabilization criterions are satisfied. Both rules and fuzzy sets (FSs) of T2FLCs are optimized by guaranteed stability rules to tackle the effect of perturbations and estimation errors. Results and Discussion: It is shown that a well voltage/energy regulation performance is achieved under variation of temperature, suddenly changes of load and variation of irradiation. A comparison with similar controllers demonstrates the superiority of the suggested approach. Conclusion: The suggested regulator do not depend on the mathematical models, and results in good accuracy under difficult conditions, then it can be used in various applications.

Antibiotic resistance in uropathogens has increased substantially and severely affected treatment of urinary tract infections (UTIs). Lately, some new formulations, including meropenem/vaborbactam (MEV), ceftazidime/avibactam (CZA), and ceftolozane/tazobactam (C/T) have been introduced to treat infections caused by drug-resistant pathogens. This study was designed to screen Enterobacteriales isolates from UTI patients and to assess their antimicrobial resistance pattern, particularly against the mentioned (new) antibiotics. Phenotypic screening of extended-spectrum β-lactamase (ESBL) and carbapenem resistance was followed by inhibitor-based assays to detect K. pneumoniae carbapenemase (KPC), metallo-β-lactamase (MBL), and class D oxacillinases (OXA). Among 289 Enterobacteriales, E. coli (66.4%) was the most predominant pathogen, followed by K. pneumoniae (13.8%) and P. mirabilis (8.3%). The isolates showed higher resistance to penicillins and cephalosporins (70–87%) than to non-β-lactam antimicrobials (33.2–41.5%). NDM production was a common feature among carbapenem-resistant (CR) isolates, followed by KPC and OXA. ESBL producers were susceptible to the tested new antibiotics, but NDM-positive isolates appeared resistant to these combinations. KPC-producers showed resistance to only C/T. ESBLs and carbapenemase encoding genes were located on plasmids and most of the genes were successfully transferred to recipient cells. This study revealed that MEV and CZA had significant activity against ESBL and KPC producers.

In this paper, the entropy generation (EGen) and exergy of a solar collector (SC) with alumina/ethylene glycol-water (50:50) nanofluid (NFs) flow are calculated. The tubes and the absorber plate of the collector are made of copper and steel, and the results of both materials are compared. Tubes with hexagonal cross section are considered. Nanoparticles (NPs) with four different shapes of platelet, brick, blade, and cylinder are considered, and their effect is evaluated. Volume fraction (ϕ) changes in the range of 0–4%, and mass flow rate varies from 0.25 to 1 kg/s. These parameters as well as the material of collector tubes and the shape of NPs are the variables of this study and their effect on fluid frictional entropy generation (Sg,ff), thermal entropy generation (Sg,th), total entropy generation (Sg,tot), exergy output (Exout), and exergy loss (Exloss) is examined. Proposed relationships and an in-house code in MATLAB software are used for analysis. The results demonstrated that the use of copper tube leads to smaller amounts of Sg,ff, and Sg,tot than steel tube. Besides, the Exout for cooper tubes is higher than that for steel ones. An increment in the flow rate enhances Sg,tot. Increasing the fluid mass flow rate from 0.25 to 1 kg/s increases the values of Sg,tot 7.9 and 8.4 times for the steel and copper collectors, respectively. The addition of NPs reduces Sg,th but enhances Sg,ff at high values of ϕ. The addition of 4% of all shapes NPs intensifies the magnitudes of Exout and Exloss.

In this numerical work, the cooling performance of water–Al2O3 nanofluid (NF) in a novel microchannel heat sink with wavy walls (WMH-S) is investigated. The focus of this article is on the effect of NP diameter on the cooling efficiency of the heat sink. The heat sink has four inlets and four outlets, and it receives a constant heat flux from the bottom. CATIA and CAMSOL software were used to design the model and simulate the NF flow and heat transfer, respectively. The effects of the Reynolds number (Re) and volume percentage of nanoparticles (Fi) on the outcomes are investigated. One of the most significant results of this work was the reduction in the maximum and average temperatures of the H-S by increasing both the Re and Fi. In addition, the lowest Tmax and pumping power belong to the state of low NP diameter and higher Fi. The addition of nanoparticles reduces the heat sink maximum temperature by 3.8 and 2.5% at the Reynolds numbers of 300 and 1800, respectively. Furthermore, the highest figure of merit (FOM) was approximately 1.25, which occurred at Re=1800 and Fi = 5%. Eventually, it was revealed that the best performance of the WMH-S was observed in the case of Re=807.87, volume percentage of 0.0437%, and NP diameter of 20 nm.

In this article, alumina/water nanofluid (NF) flow in a heatsink (H-S) with wavy microchannels (W-MCs) is simulated. The H-S is made of aluminum containing four similar parts. Each part has an inlet and outlet. Constant heat flux is applied on the bottom of the H-S. The study is based on two-phase (T-P) mixture and single-phase (S-P) models to determine the difference between these two types of simulations. FLUENT software and the control volume method were used for simulations. The volume control method is employed to solve equations. The effective variables include the volume fraction 0 < φ < 5% of alumina and Reynolds number (Re) 300 < Re < 1800. The maximum H-S bottom temperature, the required amount of pumping power (PP), the temperature uniformity, and the heat resistance of the H-S are the outputs studied to simulate the S-P and T-P models. The results show that the use of the T-P model has less error in comparison with the experimental data than the S-P model. An increment in the Re and φ reduces the maximum temperature (M-T) of the H-S. The S-P model, especially at a higher value of φ, leads to a lower M-T value than the T-P model. The S-P model shows a 0.5% greater decrease than the T-P model at the Reynolds number of 300 by enhancing the volume percentage of nanoparticles (NPs) from 1 to 5%. Temperature uniformity is improved with Re and φ. The reduction of H-S thermal resistance with Re and φ is the result of this study. Adding NPs to water, especially at higher amounts of φ, enhances the required PP. The T-P model predicts higher PP than the S-P one, especially at a high value of φ. The T-P model shows 4% more PP than the S-P model at Re = 30 and a volume fraction of 4%.

Owing to ecological concerns and the rapid increase in fossil fuel consumption, sustainable and efficient generation technologies are being developed. The present work aimed at manufacturing DSSC that is based on natural elements for converting the sun energy into electrical energy. ZnO nano materials are used in solar cells as binary compound semiconductor according to their stability, better conductivity, excellent mobility, the best affinity of electrons, and lower cost compared to other semiconductors. Recently, nanocellulose has shown potential as an advanced nanomaterial used in electrochemical conversion devices since it is considered the best abundant Earth biopolymer and is inexpensive and versatile. The constructed DSSC composed of plant nanocellulose (PNC) extracted from banana peel and nano-chlorophyll dye extracted from aloe vera were evaluated as the electrolyte and sensitiser, respectively. With increasing PNC content from 0 to 32 wt.%, both PV parameters and lifetime increase, and voltage decay decreases. The nano particles size modification for three materials carried by ultrasonic waves. Increasing the ultrasonic wave exposure time reduced the size of the Chl particles. The addition of PNC from banana peel to DSSC electrolyte is shown effective. The effect of varying the PNC/nano-chlorophyll content (0–32 wt.%) on the photovoltaic parameters of the DSSC was investigated. The addition of PNC significantly increased the fill factor and sunlight conversion efficiency. The DSSCs showed acceptable performance under relatively low irradiation conditions and different light intensities, indicating that they are suitable for outdoor applications.

The electrochemical energy storage that based on earth-abundant materials is essential because of the future demands. Because of carbon-based architecture supercapacitors, rapid charging/discharging, and long life cycle, they considered attractive compared to chemical to batteries. Therefore, copper oxide (CuO) as positive electrode and reduced grapheme oxide (rGO) as negative electrode materials were used for a high-performance supercapacitor in a low cost, simple, and ecofriendly method. During the present work, synthesized reduced graphene oxide/copper oxide (rGO/CuO) nanocomposite using a simple chemical method is carried and investigated. The crystallinity index (Ic) of CuO, 1.0 M rGO/CuO and rGO was 90.61%, 88.42%, and 86.25%, respectively, at 500 °C and one h, while it was 76.30%, 73.51%, and 67.77respectively, at 500 °C and 30 h. As the test temperature increases, Ic% of both rGO and 1.0 M rGO/CuO increases, and that of CuO decreases. As the test period increases, Ic% for rGO, CuO, and 1.0 M rGO/CuO decreases. As the molarity concentration increased, the crystallinity index of rGO/CuO composites increased. The specimens characteristics are carried and investigated using; EDX, SEM, GC/MS, and XRD analysis. The appearance of the peaks at 2θ = 22.20° and 43.58° were related to GO, and peaks at 22°, 20°, 43.58°, 50.70°, and 74.37° indicated the synthesis of the nanocomposite.

In this study, we synthesized a reduced form of graphene oxide/copper oxide (rGO/CuO) nanocompounds produced at rGO wt. of 0.125%, 0.25%, 0.5% and 1%. The crystallinity indexes for rGO and rGO/CuO increased, and that for CuO decreased as the test temperatures increases, while the crystallinity indexes of rGO, CuO and rGO/CuO decreases with test periods increment. Measurement by dynamic light scattering reported average crystallite sizes of 0.7, 8.8, 25.4, 38.5 nm for 0.125 wt.% rGO/CuO, 0.25 wt.% rGO/CuO, 0.50 wt.% rGO/CuO and 1.0 wt.% rGO/CuO respectively. The electrochemical properties of the nanocomposites were checked. The rGO/CuO XRD peaks were 18.114320 Å, 225.1856 Å, 321.41740 Å, and 365.98290 Å, with 11.051640%, 0.461075%, 0.280083%, and 0.174259% for 2ϴ of 22.2031°, 43.5865°, 50.7050°, and 74.3729°, respectively. FTIR spectroscopy identified the existence of vibrational frequencies with pseudo-capacitance at 458 cm−1 which confirmed the presence of rGO-CuO nanoparticles. The voltammetry of rGO-CuO indicated the increment of electrochemical activity, large capacitance, and conduction in the reduced rGO/CuO composite. For rGO wt. of 0.125%, 0.25%, 0.5%, and 1.0%, the rGO/CuO composite specific capacitance was 561 F/g, 582 F/g, 597 F/g, and 611 F/g, respectively, which indicated good electrochemical performance.

In recent years, consumers have increasingly demanded nutritious, healthy, and fresh-like food products with high organoleptic quality. Watermelon is rich in water, which is 92% mandatory for body functioning, and contains several vitamins, amino acids, antioxidants, carotenoids, and lycopenes with various health benefits. The present study examines the combined effect of ultrasound (US) and microwave (MW) on the physico-chemical and phytochemicals of watermelon juice during storage (up to 120 days). Sonication was employed for different time intervals, particularly from 2 to 8 min at 20 kHz frequency and 525 W power, while microwave was applied at two different time intervals (1 min 50 s and 2 min) at 1000 W power and a frequency of 2450 MHz. The product was stored at 4 °C up to 120 days for further examination. Our results revealed that treatment T5 (10 min ultrasound & 1 min 50 s microwave) manifested the maximum cloud value (3.00), acidity (0.15%), vitamin C content (202.67 mg/100 mL), phenolics (852.57 mgGAE/100 mL), flavonoids (1970.9 µg CE/100 mL), and total antioxidant activity (8650.3 µg equivalent of ascorbic acid/mL of juice). Sonication in combination with microwave proved to be an efficient technique for increasing the antioxidant potential of watermelon juice. Thus, US and MW treatments may be incorporated for enhancing the phytochemical release and shelf life of watermelon juice.

This study aimed at analyzing the performance of a corrosion resistant coating made from tri-iron tetraoxide (Fe3O4) nanoparticles (NPs) and (Butyl-2-methylprop-2-enoate)-grafted alignate/Fe3O4 nanocomposite. Two methods were used to characterize the combination; Thermo Gravimetric Analysis (TGA) and the Differential Scanning Calorimetry (DSC). It was observed that the rate of corrosion of the carbon steel was greatly influenced by the molarities of HCl used, temperature and time of immersion. Corrosion rate was found to increase with increase in molarity of the hydrochloric acid and temperature but was inversely proportional to the time of immersion. Carbon steel was coated with the corrosion resistant combination using the hot-dip coating method. To characterize the coating, Scanning Electron Microscope (SEM), Energy dispersive X-Ray (EDX), Fourier transform infrared (FT-IR) and X-Ray Diffraction (XRD) methods were used. Electrochemical studies (Tafel polarization and cyclic voltametry) showed that the optimum conditions for prevention of corrosion of the carbon steel were 150 °C and immersed time of 2 hrs. The efficiency of coating varied between the 2 combinations, with PBMA-gft-Alg/Fe3O4 nanocomposite being more effective than Fe3O4NPs coating.

The capabilities of nanofluids in boosting the heat transfer features of thermal, electrical and power electronic devices have widely been explored. The increasing need of different industries for heat exchangers with high efficiency and small dimensions has been considered by various researchers and is one of the focus topics of the present study. In the present study, forced convective heat transfer of an ethylene glycol/magnesium oxide-multiwalled carbon nanotube (EG/MgO-MWCNT) hybrid nanofluid (HNF) as single-phase flow in a heat exchanger (HE) with elliptical corrugated tubes is investigated. Three-dimensional multiphase governing equations are solved numerically using the control volume approach and a validated numerical model in good agreement with the literature. The range of Reynolds numbers (Re) 50 < Re < 1000 corresponds to laminar flow. Optimization is carried out by evaluation of various parameters to reach an optimal case with the maximum Nusselt number (Nu) and minimum pressure drop. The use of hybrid nanofluid results in a greater output temperature, a higher Nusselt number, and a bigger pressure drop, according to the findings. A similar pattern is obtained by increasing the volume fraction of nanoparticles. The results indicate that the power of the pump is increased when EG/MgO-MWCNT HNFs are employed. Furthermore, the thermal entropy generation reduces, and the frictional entropy generation increases with the volume fraction of nanoparticles and Re number. The results show that frictional and thermal entropy generations intersect by increasing the Re number, indicating that frictional entropy generation can overcome other effective parameters. This study concludes that the EG/MgO-MWCNT HNF with a volume fraction (VF) of 0.4% is proposed as the best-case scenario among all those considered.

The Markov jump systems (MJSs) are a special case of parametric switching system. However, we know that time delay inevitably exists in many practical systems, and is known as the main source of efficiency reduction, and even instability. In this paper, the stochastic stable control design is discussed for time delay MJSs. In this regard, first, the problem of modeling of MJSs and their stability analysis using Lyapunov-Krasovsky functions is studied. Then, a state-feedback controller (SFC) is designed and its stability is proved on the basis of the Lyapunov theorem and linear matrix inequalities (LMIs), in the presence of polytopic uncertainties and time delays. Finally, by various simulations, the accuracy and efficiency of the proposed methods for robust stabilization of MJSs are demonstrated.

One of the factors that significantly affects the efficiency of oil and gas industry equipment is the scales formed in the pipelines. In this innovative, non-invasive system, the inclusion of a dual-energy gamma source and two sodium iodide detectors was investigated with the help of artificial intelligence to determine the flow pattern and volume percentage in a two-phase flow by considering the thickness of the scale in the tested pipeline. In the proposed structure, a dual-energy gamma source consisting of barium-133 and cesium-137 isotopes emit photons, one detector recorded transmitted photons and a second detector recorded the scattered photons. After simulating the mentioned structure using Monte Carlo N-Particle (MCNP) code, time characteristics named 4th order moment, kurtosis and skewness were extracted from the recorded data of both the transmission detector (TD) and scattering detector (SD). These characteristics were considered as inputs of the multilayer perceptron (MLP) neural network. Two neural networks that were able to determine volume percentages with high accuracy, as well as classify all flow regimes correctly, were trained.

This paper proposes a barrier function adaptive non-singular terminal sliding mode controller for a six-degrees-of-freedom (6DoF) quad-rotor in the existence of matched disturbances. For this reason, a linear sliding surface according to the tracking error dynamics is proposed for the convergence of tracking errors to origin. Afterward, a novel non-singular terminal sliding surface is suggested to guarantee the finite-time reachability of the linear sliding surface to origin. Moreover, for the rejection of the matched disturbances that enter into the quad-rotor system, an adaptive control law based on barrier function is recommended to approximate the matched disturbances at any moment. The barrier function-based control technique has two valuable properties. First, this function forces the error dynamics to converge on a region near the origin in a finite time. Secondly, it can remove the increase in the adaptive gain because of the matched disturbances. Lastly, simulation results are given to demonstrate the validation of this technique.

Agricultural residues management is considered to be a vital strategy in order to accomplish resource conservation and to maintain the quality of the environment. In recent years, biofibers have attracted increasing interest due to their wide applications in food packaging and in the biomedical sciences. These eco-friendly polymers reduce rapidly and replace the usage of the petroleum-based synthetic polymers due to their safety, low production costs, and biodegradability. This paper reports an efficient method for the production of the cellulose acetate biofiber from flax fibers and cotton linters. The used process satisfied a yield of 81% and 54% for flax fibers and cotton linters respectively (based on the weight of the cellulosic residue used). The structure of the produced bioplastic was confirmed by X-ray diffraction, FT-IR and gel permeation chromatography. Moreover, this new biopolymer is biodegradable and is not affected by acid or salt treatment but is alkali labile. A comparison test showed that the produced cellulose acetate was affected by acids to a lesser extent than polypropylene and polystyrene. Therefore, this new cellulose acetate bioplastics can be applied in both the food industry and medicine. Keywords: Cotton linters, Flax fibers, Cellulose acetate, Preparation, Characterization

In this study, an adaptive nonsingular finite time control technique based on a barrier function terminal sliding mode controller is proposed for the robust stability of nth-order nonlinear dynamic systems with external disturbances. The barrier function adaptive terminal sliding mode control makes the convergence of tracking errors to a region near zero in the finite time. Moreover, the suggested method does not need the information of upper bounds of perturbations which are commonly applied to the sliding mode control procedure. The Lyapunov stability analysis proves that the errors converge to the determined region. Last of all, simulations and experimental results on a complex new chaotic system with a high Kaplan–Yorke dimension are provided to confirm the efficacy of the planned method. The results demonstrate that the suggested controller has a stronger tracking than the adaptive controller and the results are satisfactory with the application of the controller based on chaotic synchronization on the chaotic system.

In this paper, a common and widely used micro-heat sink (H/S) was redesigned and simulated using computational fluid dynamics methods. This H/S has a large number of microchannels in which the walls are wavy (wavy microchannel heat sink: WMCHS). To improve cooling, two (Al2O3 and CuO) water-based nanofluids (NFs) were used as cooling fluids, and their performance was compared. For this purpose, studies were carried out at three Reynolds numbers (Re) of 500, 1000, and 1500 when the volume percent (φ) of the nanoparticles (NPs) was increased to 2%. The mixture two-phase (T-P) model was utilized to simulate the NFs. Results showed that using the designed WMCHS compared to the common H/S reduces the average and maximum temperatures (T-Max) up to 2 °C. Moreover, using the Al2O3 NF is more suitable in terms of WMCHS temperature uniformity as well as its thermal resistance compared to the CuO NF. Increasing the φ is desirable in terms of temperature, but it enhances the pumping power (PP). Besides, the Figure of Merit (FOM) was investigated, and it was found that the value is greater at a higher volume percentage.