Implications of Metamaterial on Ultra-Wide Band Microstrip Antenna Performance

This study is addressing the slotted ring resonator effect on the performance of the ultra-wide band (UWB) microstrip antenna. Two types of metamaterial with double slotted ring resonators (SRR), circular (C-SRR) and square (S-SRR), are studied and implemented on back of the antenna. The design examines the effect of the number of the SRR and its position with respect to the antenna’s ground plane and the rotation of the inner and outer C-SRR rings on different antenna characteristics. The dimensions of the antenna are 45 mm × 31 mm × 1.27 mm. The implementation of the SRR increased the antenna bandwidth to cover the range from 2.2 GHz to 9.8 GHz with rejected bands and frequencies. Antenna simulated characteristics like return loss, maximum gain and radiation pattern are obtained utilizing HFSS. The return loss measurement and the VSWR of the antenna with all SRR configuration studied are in good agreement with simulated results.

Pattern of dermatological involvement in early postmenopausal period: a cross sectional study

<p class="abstract"><strong>Background:</strong> The high burden of menopausal symptoms notwithstanding, there is a paucity of published work evaluating its impact specifically on the skin and mucosa. With high incidence of underreported cases in developing countries, active screening of all women is essential for accurate assessment of prevalence of cutaneous features, as highlighted by this study. The objective of this study is to assess clinical patterns of dermatosis in menopausal women.</p><p class="abstract"><strong>Methods:</strong> A cross‑sectional study conducted in the dermatology department conducted on postmenopausal patients below 65 years having dermatoses after taking their written consent. Data analysis using SPSS 20.0.<strong></strong></p><p class="abstract"><strong>Results:</strong> Of 350 postmenopausal women, 165 had genital involvement, atrophic vaginitis (41.21%) being the most common manifesting typically as vaginal dryness. Of 82 women having oral complaints, 42.7% women had complaints of pain or difficulty swallowing in the absence of mucosal lesions. Of the total sample size, 34% women had had female pattern hair loss, maximum women with grade I-2 (45.4%) and I-3 (36.13%). Two key findings which we did not find previous records of included incidence of keratoderma climactericum (2.29%) and hirsutism in early menopause which we found to be 8%. It is important to note that only 28% of women were aware that their complaints were related to menopause or chose to seek active treatment for existing complaints.</p><p class="abstract"><strong>Conclusions:</strong> This study highlights the various clinical patterns of postmenopausal dermatoses to raise awareness in dermatologists and gynecologists for prompt diagnosis, treatment and patient education.</p><p class="abstract"> </p>

Preoperative Elevated International Normalized Ratio Cannot Increase Transfusion or Complication in Primary Total Hip Arthroplasty: A Retrospective Study of 552 Cases

Background: Verify if the elevated preoperative International Normalized Ratio (INR) can increase transfusion and complication rate in primary total hip arthroplasty.Methods: We retrospectively reviewed the database of adults who underwent primary total hip arthroplasty between 2014 to 2018 by the same surgeon. 552 cases were assigned into 3 groups by preoperative INR class: INR≤0.9, 0.9＜INR＜1.0, and INR≥1.0 eventually. We regarded the transfusion rate as the primary outcome. We also included perioperative blood loss, maximum Hb-drop, postoperative anemia needs medicine, length of stay (LOS), re-operation, the complication rate in 90 days and mortality as the secondary outcomes. Univariable analyses were utilized to compare baselines and outcomes between groups. Binary Logistic Regression was used to adjust differences of baselines among groups.Results: All the cases had an INR＜1.5. Among all the cases, 93(16.8%) had INR≤0.9, 268 (48.6%) had 0.9＜INR＜1.0, and 191 (34.6%) had INR≥1.0, respectively. In the univariable analyses, with the INR elevated, The transfusion rates increased from 1.08% for INR≤0.9, 1.12% for 0.9＜INR＜1.0 to 5.76% for INR≥1.0 (p＜0.05). The overall complication rate increased from 10.8% for INR≤0.9, 16.4% for 0.9＜INR＜1.0 to 22.5% for INR≥1.0 (p＜0.05). When controlling for the demographics and comorbidities characteristics, there was no statistically significant difference when evaluating the odds of transfusion nor overall complication rate between the groups (p＞0.05).Conclusions: The transfusion and complication rate cannot increase along with the INR elevated in primary THA. With the improvement of arthroplasty protocol and use of tranexamic acid, the INR＜1.5 was still a conventional safe threshold.

The Effect of Compressible Flow on Heat Transfer Performance of Heat Exchanger by Computational Fluid Dynamics (CFD) Simulation

As a part of vehicle thermal management, water-cooled intercoolers play an important role in engine efficiency. The incompressible simulation model was usually applied to estimate the performance of water-cooled intercoolers. In this paper, the computational fluid dynamics (CFD) compressible model is taken to analyze more accurate prediction models. The rate of section change, heat exchange, and the surface friction coefficient are used as the comparison basis of the compressible flow model and incompressible model on the pressurized air side of the water-cooled intercooler. By comparing the simulation results of the air side, it was found that the compressible simulation is closer to the experimental value than the incompressible simulation. Compared with the experiment, the compressible model heat transfer maximum value of deviation is 6.5%, and the pressure loss maximum deviation is 7.5%. This provides guidance to optimize the design of heat exchangers, in order to save on costs and shorten development times.

Screening of hearing ability and hearing threshold among traffic police

Introduction: Traffic police are continually exposed to loud noise. The pure tone audiometric screening for hearing test has not been done in Biratnagar Nepal. So, we conducted a study to screen hearing ability and also to find out hearing thresholds among traffic police with normal hearing ability. Materials and methods: The study was conducted among 36 traffic police personnel. The 25dB sound was administered with audiometer (name) in different frequencies (1 kHz, 2 kHz, 3 kHz, 4 kHz and 8 kHz) for screening hearing loss in left and right ears. The threshold for hearing among normal hearing traffic personnel was compared with controls in all the frequencies. Result: Among 36 traffic police, 17(47.2%) had hearing loss. Maximum (n=8) hearing loss was seen in 4 kHz (4 - unilateral and 4 – bilateral) followed by 3 kHz (n=4, 3 unilateral and 1 bilateral) and mixed 3kHz and 4 kHz frequencies. The percentage of hearing loss in 2 kHz, 3 kHz and 4 kHz frequencies was more in left ear compared to right. The threshold for hearing loss was higher in traffic police compared to controls .In the left ear, it was only in 4kHz {(25.91+6.64 Vs 20.45±4.15,( p=.034)} whereas in right ear, the threshold was higher in 3 kHz {20.45±5.22 Vs 15.91±4.90, (p=0.04)}, 4 kHz {25.45±12.54 Vs 16.82±5.60, (p=0.05)} and 8000 kHz {18.64±17.62 Vs 6.36±3.23, (p=0.04) . Conclusion: The hearing loss was present in 47.2% of traffic policemen predominantly in 4 kHz. The threshold for hearing was also higher among traffic police compared to controls.

Model-Based Optimization of an LLC-Resonant DC-DC Converter

The study presented in the paper is to guarantee the performance of the LLC DC-DC converter using model-based optimization. The primary scope of the study is to maintain the output parameters regardless of the variation of the values of the circuit elements. In engineering practice, it is known that any schematic element cannot be reproduced with an absolute accuracy of features. In addition, its main parameters change during operation due to changes in operating temperature, aging, operating modes and so on. Optimization procedures are a tool for finding the most appropriate values for circuit elements, with selected constraints, target functions and operating modes. In electronic converters, these are most often: minimal loss, maximum efficiency, the critical-aperiodic transition process, realization of certain dynamics, appropriate modes of operation and so on. The results obtained show that using the proposed approach produces more robustness to disturbances and tolerances, with improved dynamics and faster transient processes. On the other hand, the value of the circuit elements is smaller, and reliable operation of the protection and automatic regulation systems is achieved.

Water/PEG Mixtures: Phase Behavior, Dynamics and Soft Confinement

Polyethylene glycol is water soluble and forms an eutectic system with water. The eutectic temperature is −19 °C for M=1500 g mol−1 and increases with molecular weight. The dielectric relaxation spectrum of the mixtures exhibits a strong loss maximum in ϵ″ (ω) similar to pure water. Relaxation time increases with the addition of PEG. Activation energies exhibit a maximum of 0.35 eV at molar fraction χp≈0.2. This compares well with results on ethanol water mixtures. Adding PEG molecules to nanoscopic water droplets of inverse microemulsions has only small impact on the bending modulus κ of a non-ionic microemulsion. In AOT based microemulsions an increase or decrease of κ is found in dependence on the size of the droplets. This is in accordance with the variation of the dynamic percolation transition in the same systems.

Micronised bran-enriched fresh egg tagliatelle: Significance of gums addition on pasta technological features

The aim of the work was to produce fibre-enriched fresh pasta based on micronised wheat bran and durum wheat semolina with appropriate techno-functional properties. Wheat semolina was replaced with fine particle size (50% below 75 µm) wheat bran – up to 11.54% (w/w). A Box–Behnken design with randomised response surface methodology was used to determine a suitable combination of carboxymethylcellulose, xanthan gum and locust bean gum to improve pasta attributes: minimum cooking loss, maximum values for water gain and swelling index, as well as better colour and texture characteristics before and after cooking. The proximate chemical composition of wheat semolina and bran was determined and the microstructure of uncooked pasta was observed as well. From the response surface methodology analysis, it is recommended to use: (i) xanthan gum over 0.6% w/w as it led to bran-enriched pasta with a better developed structure and superior cooking behaviour, (ii) a combination of xanthan gum (0.8% w/w) and carboxymethylcellulose (over 0.6% w/w) to enhance uncooked pasta yellowness.

Irrigation Measurement System for Dry Areas Based on WSN

Agriculture requires a certain amount of water and the land has a maximum liquid holding capacity that should not be exceeded. Water pressure provides the kinematic energy used on irrigation systems to spray the water on the field. The amount of water that the irrigation system can provide per hour should be carefully monitored to save water in dry areas. The paper presents a system with wireless nodes for water flow measurement in several pipes simultaneously. The system employs YF S201C flow sensors, connected to wireless nodes. Each node sends reports every second to a master node connected to a computer. The received data is presented in a web-based platform to see the current water flow on each of the three pipes. Results show sensor nodes exhibit a 4% average error, and 9% packet loss maximum. Both values are adequate for crop irrigation applications.