bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Influence of Connection Defects on Joint Strength of Half‐Grouted Sleeve Splicing of Rebar
Authors: Guo Hong , Zhang Jiaxin , Wang Changwei
Published: June 2020

The different types of defects of half grouting sleeves will remarkably increase the risks of precast concrete structures. In order to better understand the defects of rebar connections between half grouting sleeves, six different test groups on insufficient grout height, insufficient compactness, rebar offset, insufficient rebar anchor length, overtime grouting, and control group had been researched. The uniaxial tension experiments were conducted for the 24 different specimens, and load‐slip curves were also analyzed. The results of the experiments showed that the outside of the rebar was snapped off as for the destruction mode, while the destruction mode changed as the increment of the degree of defect surpasses the critical value. The bearing capacity and deformability were dropped with the increase in the degree of defects, and a critical value of rebar anchoring length of sleeve was discovered. In the end, different finite‐element models were built based on different deficient situations, and load‐slip constitutive model was obtained, which would be helpful to evaluate the structural performance of precast concrete structures in construction.
Recycling and Reusing Polyethylene Waste as Antistatic and Electromagnetic Interference Shielding Materials
Authors: Rahaman Mostafizur , Al Ghufais Ibrahim Abdullah , Periyasami Govindasami , Aldalbahi Ali
Published: June 2020

The aim of this work is to manage the waste product based on polyethylene (PE) films by recycling and reusing it as antistatic material for electronic packaging and electromagnetic interference (EMI) shielding material for protecting electronic equipment from interference of EM radiation. To achieve this, a conductive carbon black has been mixed with the PE waste at different weight percent values by ultrasonication via a solution mixing process. Mixing time for sonication was determined by ultraviolet-visible (UV-VIS) spectra. A differential scanning calorimetry (DSC) study showed that the low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) are immiscible in their blend composition. The tensile properties of PE have reduced substantially after reprocessing. However, the addition of carbon black has improved its strength up to a certain loading. The electrical percolation threshold values, calculated using the classical power law and sigmoidal Boltzmann model, were obtained at 3.5 and 2.8 wt% loading of carbon black, respectively. The conductivity result revealed that 1-2 wt% carbon-loaded composites can be used as antistatic material. The composites, having carbon loading above 4 wt%, can be effective materials for EMI shielding application. The 10 wt% carbon-loaded composite exhibits EMI SE value 33 dB which means there is approximately 99.93% protection of EM radiation at the sample thickness of 1.0 mm. Moreover, FTIR analysis, thermal stability, AC conductivity, dielectric properties, permeability, and current-voltage characteristics are also discussed in detail. There is a substantial increment in thermal stability, and dielectric properties are observed with the addition carbon black loading within the polymer matrix.
Minimally Invasive Parafascicular Surgery (MIPS) for Spontaneous Intracerebral Hemorrhage Compared to Medical Management: A Case Series Comparison for a Single Institution
Authors: Phillips Victoria L. , Roy Anil K. , Ratcliff Jonathan , Pradilla Gustavo
Published: June 2020

Objective. We compared the safety and effectiveness of minimally invasive parafascicular surgery (MIPS) as a frontline treatment for spontaneous supratentorial ICH to medical management. Patients. The sample consisted of 17 patients who underwent MIPS from January 2014 to December 2016 and a comparison group of 23 patients who were medically managed from June 2012 to December 2013. All had an International Classification of Disease (ICD) diagnosis of 431 and were treated at Grady Memorial Hospital, an urban, public, safety-net hospital. Methods. The primary endpoint was risk of inpatient mortality. Secondary endpoints were rates of inpatient infection and favorable discharge status, defined as discharge to home or rehabilitation facility. Demographics and pre- and postclinical outcomes were compared using t-tests, the Mann–Whitney test, and chi-squared tests for continuous, ordinal and categorical measures, respectively. Cox proportional hazard models were used to estimate the time to inpatient death. Logistic regression analyses were used to determine treatment effects on secondary outcomes. We also conducted exploratory subgroup analyses which compared MIPS to two medical management subgroups: those who had surgery during their hospitalization and those that did not. Results. Two patients (12%) died in the MIPS group compared to three (12%) in the medical management group. MIPS did not increase the risk of inpatient mortality relative to medical management. Rates of inpatient infection did not differ significantly between the two groups; eight MIPS patients (47%) and 13 medically managed patients (50%) contracted infections. MIPS significantly increased the likelihood of favorable discharge status (odds ratio (OR) 1.77; 95% CI, 1.12–21.9) compared to medical management. No outcome measures were significantly different between MIPS and the medical management subgroup without surgery, while rates of favorable discharge were higher among the MIPS patients compared to the medical management group with surgery. Conclusions. These data suggest that MIPS, as a frontline treatment for spontaneous ICH, versus medical management for spontaneous ICH warrants further investigation.
Trajectory Planning and Tracking for Carrier Aircraft-Tractor System Based on Autonomous and Cooperative Movement
Authors: Yu Minghui , Gong Xue , Fan Guowei , Zhang Yu
Published: June 2020

The solution of how to plan out the cooperative moving trajectory autonomously and control the motion of carrier-based aircraft timely and accurately is the key to helping improve the overall deck operation efficiency. The main problem discussed in this article is coordinated trajectory planning strategy for multicarrier aircraft and cooperative control between tractor and carrier aircraft. First, the kinematic model and three-degree-of-freedom dynamics model of the towbarless traction system are established. Then, a coevolution mechanism for aircraft systems is proposed to ensure coordinated trajectory planning among multiple aircraft and a trajectory adapted to the tractor-aircraft system is generated based on the hybrid RRT∗ algorithm. Next, a double-layer closed-loop controller is designed for the trajectory tracking of the tractor-aircraft system on the deck under the constraints of incomplete constraints and various physical conditions. It includes an outer model predictive controller which effectively controls the cooperative motion between the carrier aircraft and tractor and an inner torque control strategy based on adaptive fuzzy PID control which strictly ensures the stability of the system. Simulation results demonstrate that the controller is more rapid, more accurate, and more robust in tracking line trajectory with initial deviation, sine curve with large curvature, and complex trajectories on decks compared with backstepping control and LQR algorithm.
Long Noncoding RNASBF2‐AS1 Promotes Gastric Cancer Progression via Regulating miR‐545/EMS1 Axis
Authors: He Mingyuan , Feng Li , Qi Lingzhi , Rao Min , Zhu Yonggang
Published: June 2020

Objective. Long noncoding RNA (LncRNA) SBF2‐AS1 was reportedly to function as an oncogene in several types of cancers, such as hepatocellular carcinoma, nonsmall cell lung cancer, glioma, and colorectal cancer. However, the biological roles and regulatory mechanisms of SBF2‐AS1 in gastric cancer (GC) are unknown. Methods. The expression of SBF2‐AS1 and miR‐545 were examined in GC tissues and cell lines via real‐time quantitative PCR. The relationship of SBF2‐AS1 with miR‐545 was verified via dual‐luciferase reporter gene assay and RNA immunoprecipitation. The influences of SBF2‐AS1 on cell proliferation, migration, and invasion were determined using cell counting Kit‐8 (CCK‐8), wound healing, and transwell invasion assays, respectively. Results. LncRNA SBF2‐AS1 expression was upregulated in GC tissues, especially in advanced clinical stage cases. Moreover, increased SBF2‐AS1 indicated a poor survival rate. Functionally, the downregulation of SBF2‐AS1 by siRNA in GC cells suppressed the proliferation, migration, and invasion. In terms of mechanism, SBF2‐AS1 can directly bind to miR‐545 and regulate its expression. Moreover, SBF2‐AS1 knockdown significantly decreased the expression of EMS1, which was the direct target of miR‐545. Importantly, inhibition of miR‐545 or overexpression of EMS1 partially reversed SBF2‐AS1‐depletion‐caused suppression on proliferation, migration, and invasion. Conclusion. These findings elucidated a crucial role of SBF2‐AS1 as a miR‐545 sponge in GC cells, suggesting that SBF2‐AS1 might be a potential target for GC.
Let‐7c‐5p Is Involved in Chronic Kidney Disease by Targeting TGF‐β Signaling
Authors: Wang Zhenguo , Zhou Cuixing , Sun Yangyang , Chen Yimeng , Xue Dong
Published: June 2020

The purpose of the present study was to investigate the expressions of hsa‐let‐7c‐5p and TGF‐β signaling‐related molecules and their correlations with clinical characteristics in chronic kidney disease (CKD). Twenty‐three biopsy specimens of CKD patients and 20 negative control tissues were selected. Quantitative real‐time PCR (qPCR) was used for the detection of hsa‐let‐7c‐5p, transforming growth factor β (TGF‐β) and TGF‐β receptor type 1 (TGF‐βR1) expression levels. Target gene of hsa‐let‐7c‐5p was verified by dual‐luciferase reporter assay. A significant decrease of hsa‐let‐7c‐5p expression in CKD tissue was found, compared with that of normal renal tissues (p < 0.01). Expression levels of TGF‐β in CKD were increased, compared with that of normal kidney tissue (p < 0.001). The difference in the expression of TGF‐β R1 between CKD tissues and normal renal tissues was not significant (p > 0.05). A negative correlation was found between the expression of TGF‐β and renal tissue hsa‐let‐7c‐5p levels. Furthermore, hsa‐let‐7c‐5p was identified to regulate TGF‐ β1 by directly binding with the 167‐173 site in the 3 ′ untranslated region. Decreased hsa‐let‐7c‐5p levels in CKD patients was found to be associated with disease severity, which shows a negative correlation with proteinuria and creatinine levels, and a positive correlation with estimated glomerular filtration rate (eGFR), while relative TGF‐β1 expression had a positive correlation with creatinine level. In summary, changes in hsa‐let‐7c‐5p expression and its target gene TGF‐β are associated with the disease status of CKD. Let‐7c‐5p may contribute to the pathogenesis of renal fibrosis through TGF‐β signaling, a potential diagnostic and therapeutic target of the disease.
Quality and Brands of Amoxicillin Formulations in Nairobi, Kenya
Authors: Koech Lilian C. , Irungu Beatrice N. , Ng’ang’a Margaret M. , Ondicho Joyce M. , Keter Lucia K.
Published: June 2020

Antibiotics are among the most counterfeited anti‐infectious medicines in developing countries. Amoxicillin is one of the commonly prescribed, affordable, and easily accessible antibiotic in Kenya. It is a broad‐spectrum antibiotic hence commonly used in chemotherapy. This study sought to determine the quality and identify the various brands of amoxicillin and its combination amoxicillin/clavulanic acid marketed in Nairobi County. Nairobi is the capital city of Kenya, gateway for imports and exports, and the headquarters to most of the pharmaceutical distributors. Ten wards in Nairobi County representing different socioeconomic settings were purposively sampled for the study. A detailed questionnaire was used to collect background data on brands of amoxicillin and amoxicillin/clavulanic acid in the market. A total of 106 different brands were found in the market: 85 were imports while 21 were locally manufactured. Fifty‐three samples were analyzed with reference to the United States Pharmacopoeia. Amoxicillin and clavulanic acid contents for oral suspensions were determined immediately after reconstitution and 7 days thereafter to determine their stability during the prescription period. On day seven, 23.1% (3 out of 13) of amoxicillin and 66.7% (8 out of 12) amoxicillin/clavulanic acid oral suspensions presented levels below recommended limits. Uniformity of weight for amoxicillin capsules noted 13.6% (3 out of 22) failure rate, while amoxicillin/clavulanic acid tablets complied. Potency determination for all amoxicillin capsules analyzed were within required limits, but amoxicillin/clavulanic acid tablets showed 33.3% (2 out of 6) noncompliance. For amoxicillin capsule and amoxicillin/clavulanic acid tablet dissolution tests, there was 10.5% (2 out of 19) and 50% (2 out of 4) noncompliance, respectively. Overall, 37.7% of the drugs analyzed failed to comply with the Pharmacopoeia. These results highlight the presence of poor‐quality amoxicillin formulations in Nairobi County, affirming the need for regular postmarket surveillance to inform on the situation of antibiotic quality in the Kenyan market.
Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Acinetobacter baumannii Clinical Isolates in South Africa
Authors: Anane Yaw Adjei , Apalata Teke , Vasaikar Sandeep , Okuthe Grace Emily , Songca Sandile
Published: June 2020

Introduction. Carbapenem-resistant Acinetobacter baumannii has been responsible for an increasing number of hospital-acquired infections globally. The study investigated the prevalence of carbapenemase-encoding genes in clinical multidrug-resistant A. baumannii strains. Materials and Methods. A total of 100 nonduplicate multidrug-resistant A. baumannii strains were cultured from clinical samples obtained from healthcare facilities in the O. R. Tambo district. The strains were confirmed by detecting the intrinsic blaOXA-51-like gene. Antimicrobial susceptibility testing was performed by VITEK® 2 and autoSCAN-4 systems. The MIC of imipenem and meropenem was rechecked by E-test. Colistin MIC was confirmed by the broth microdilution method. Real-time PCR was performed to investigate the presence of carbapenemase-encoding genes. Results. Most strains showed high resistance rates (>80%) to the antibiotics tested. Resistance to amikacin, tetracycline, and tigecycline were 50%, 64%, and 48%, respectively. All strains were fully susceptible to colistin. The blaOXA-51-like was detected in all strains whilst blaOXA-23-like, blaOXA-58-like, blaOXA-24-like, blaIMP-1, blaVIM, and blaNDM-1 were found in 70%, 8%, 5%, 4%, 3%, and 2% of strains, respectively. None of the tested strains harboured the genes blaSIM and blaAmpC. The coexistence of blaOXA-23-like, and blaIMP-1 or blaOXA-58-like was detected in 1% and 2% strains, respectively. A distinct feature of our findings was the coharbouring of the genes blaOXA-23-like, blaOXA-58-like, and blaIMP-1 in 2% strains, and this is the first report in the Eastern Cape Province, South Africa. The intI1 was carried in 80% of tested strains whilst ISAba1/blaOXA-51-like and ISAba1/blaOXA-23-like were detected in 15% and 40% of the strains, respectively. The detection of blaOXA-23-like, ISAba1/blaOXA-51-like, ISAba1/blaOXA-23-like, and blaOXA-23-like, blaOXA-58-like, and blaIMP-1 carbapenemases in strains had a significant effect on both imipenem and meropenem MICs. Conclusions. Results showed a high level of oxacillinases producing A. baumannii circulating in our study setting, highlighting the need for local molecular surveillance to inform appropriate management and prevention strategies.
The Use of Granular Cyclopentanone as Alternative to Artificial Source of Carbon Dioxide in Improved Passive Outdoor Host Seeking Device (POHD)
Authors: Kessy Stella T. , Nyundo Bruno A. , Mnyone Ladslaus L. , Lyimo Issa N.
Published: June 2020

Reliable sources of CO2 that are relatively cheap, obtainable, and easy to sustain are immediately required for scaling up of odor-baited mosquito surveillance and control devices. Several odor-baited devices are in the pipeline; however, their scale-up against residual malaria transmission, particularly in resource poor areas, is limited by the unavailability of reliable sources of CO2 and reliance on electrical power sources among other factors. We evaluated the use of granular cyclopentanone as an alternative to artificial or yeast fermentation-produced CO2 in passive outdoor host seeking device (POHD). Experiments were conducted against semifield reared An. arabiensis within the semifield system (SFS) at Ifakara Health Institute. Mosquitoes were tested against odor-baited POHDs augmented with yeast fermentation-produced CO2, granular cyclopentanone, attractive blends (Mbita or Ifakara), or their combinations. An insecticide, bendiocarb, was a killing agent used as a proxy for marking the mosquitoes visit the POHDs. Relative attractiveness of different treatment combinations was compared based on the proportion of dead mosquitoes that visited the POHD. The POHD augmented with granules of cyclopentanone alone was attractive to An. arabiensis as much as, or more than, POHDs augmented with yeast fermentation-produced CO2. The POHD baited with CO2 attracted more mosquitoes than those POHDs baited with synthetic blends alone; when these blends are combined with CO2, they attracted more mosquitoes than individual blends. More importantly, such POHDs baited with cyclopentanone attracted far greater proportion of mosquitoes than the POHD baited with either Mbita or Ifakara blend alone. The granular cyclopentanone strongly enhanced/potentiated the attractiveness of POHD baited with Mbita blends against mosquitoes compared to that of POHD baited with Ifakara blend. Moreover, the granular cyclopentanone retained its residual activity against An. arabiensis for up to 2 months after application particularly when used in combination with Mbita blend. In conclusion, this study demonstrates that cyclopentanone granules have the potential to substitute sources of CO2 in outdoor-based surveillance and control devices, thus warranting evaluation of such alternative under realistic field conditions.
Treatment and Effect of Loess Metro Tunnel under Surrounding Pressure and Water Immersion Environment
Authors: Wang Lixin , Li Chenghan , Qiu Junling , Wang Ke , Liu Tong , Li Heng
Published: June 2020

It is possible to pass through a collapsible loess stratum during metro tunneling. When the surrounding potential water sources with pressure are induced by external influences, the tunnel structure will be influenced in the affected area of loess collapsibility. To deal with the water inrush disaster of the tunnel in a collapsible loess stratum, the mechanism of grouting diffusion in the loess stratum is analyzed. It is found that the main influencing factors of the grouting effect are the radius of the grouting ring and the permeability coefficient of the grouting ring. Then, based on the water inrush section of a metro tunnel in Xi’an city, China, the treatment effect of the project is compared and analyzed through field tests, field monitoring, and finite element simulation. The results show that the water pressure at the measuring point of the tunnel vault is reduced by 4 MPa; the maximum and the minimum principal stresses at the top of the segment lining increased by 34.9 kPa and 8.8 kPa, respectively, which is less than the increase without grouting; and the maximum displacement of the surrounding rock is reduced by 19 mm. The plastic area produced by local water source infiltration is about 62% of that before grouting. The treatment measures of grouting in the tunnel are safe and effective. This study is of valuable meaning for the treatment of water inrush disaster of a loess tunnel under the water environment.
Optimal Design of Single-Cell Experiments within Temporally Fluctuating Environments
Authors: Fox Zachary R. , Neuert Gregor , Munsky Brian
Published: June 2020

Modern biological experiments are becoming increasingly complex, and designing these experiments to yield the greatest possible quantitative insight is an open challenge. Increasingly, computational models of complex stochastic biological systems are being used to understand and predict biological behaviors or to infer biological parameters. Such quantitative analyses can also help to improve experiment designs for particular goals, such as to learn more about specific model mechanisms or to reduce prediction errors in certain situations. A classic approach to experiment design is to use the Fisher information matrix (FIM), which quantifies the expected information a particular experiment will reveal about model parameters. The finite state projection-based FIM (FSP-FIM) was recently developed to compute the FIM for discrete stochastic gene regulatory systems, whose complex response distributions do not satisfy standard assumptions of Gaussian variations. In this work, we develop the FSP-FIM analysis for a stochastic model of stress response genes in S. cerevisiae under time-varying MAPK induction. We verify this FSP-FIM analysis and use it to optimize the number of cells that should be quantified at particular times to learn as much as possible about the model parameters. We then extend the FSP-FIM approach to explore how different measurement times or genetic modifications help to minimize uncertainty in the sensing of extracellular environments, and we experimentally validate the FSP-FIM to rank single-cell experiments for their abilities to minimize estimation uncertainty of NaCl concentrations during yeast osmotic shock. This work demonstrates the potential of quantitative models to not only make sense of modern biological datasets but to close the loop between quantitative modeling and experimental data collection.
Carotid Disease and Ageing: A Literature Review on the Pathogenesis of Vascular Senescence in Older Subjects
Authors: Sertedaki Eleni , Veroutis Dimitris , Zagouri Flora , Galyfos George , Filis Konstadinos , Papalambros Alexandros , Aggeli Konstantina , Tsioli Panagiota , Charalambous George , Zografos George , Sigala Fragiska
Published: June 2020

Aging is a natural process that affects all systems of the human organism, leading to its inability to adapt to environmental changes. Advancing age has been correlated with various pathological conditions, especially cardiovascular and cerebrovascular diseases. Carotid artery (CA) is mainly affected by age-induced functional and morphological alterations causing atheromatous disease. The evolvement of biomedical sciences has allowed the elucidation of many aspects of this condition. Symptomatic carotid disease (CD) derives from critical luminar stenosis or eruption of an atheromatous plaque due to structural modifications of the vessels, such as carotid intima-media thickening. At a histologic level, the aforementioned changes are mediated by elastin fragmentation, collagen deposition, immune cell infiltration, and accumulation of cytokines and vasoconstrictors. Underlying mechanisms include chronic inflammation and oxidative stress, dysregulation of cellular homeostatic systems, and senescence. Thus, there is an imbalance in components of the vessel wall, which fails to counteract exterior stress stimuli. Consequently, arterial relaxation is impaired and atherosclerotic lesions progress. This is a review of current evidence regarding the relationship of aging with vascular senescence and CD. A deeper understanding of these mechanisms can contribute to the production of efficient prevention methods and targeted therapeutic strategies.
Access and Use of Mobile Phone in Daily Life Activities by Rural Women of Gilgit-Baltistan, Pakistan
Authors: Rahim Sabit , Qutoshi Sadruddin Bahadur , Abida Syeda , Muhammad Faqeer , Hussain Imtiaz
Published: June 2020

This study aims to investigate the access to a mobile phone, usage pattern, and its impact on mountainous rural women of two districts, i.e., Hunza and Nagar districts of Gilgit-Baltistan, Pakistan. To attain the objective of the research, the researchers have employed various statistic methods, and data were collected through a questionnaire from 190 respondents in the study area (200 respondents were selected). Initially, Kaiser–Meyer–Olkin (KMO) and Bartlett’s tests were used for sampling adequacy, and factor analysis technique was used to explain correlations among multiple outcomes. The results revealed that 80% of women in the Hunza and Nagar districts own mobile phones (access) and 63% have good skills of mobile phone usage for a variety of purposes. Moreover, 56.4% of women use mobile phones in their daily life activities; however, 23.6% disagreed with the statements. On the contrary, the results show that 71.8% women use mobile phones for security purposes. Therefore, the study recommends that effective use of the mobile phone in daily activities of mountainous rural women can be one of the effective strategies to boost their confidence level and feeling of security. Finally, socioeconomic development of the area is possible by providing technical skills related to mobile phone business to the unskilled women of the two districts.
Research of the Rheological Modification Mechanism of Crumb Rubber‐Modified Asphalt Containing Polyamide 6 Additive
Authors: Tan Zhihua , Wang Jijing
Published: June 2020

In the past few decades, the rapid growth of automobile production in China has led to the scrapping of a large number of tires. How to dispose of tires has become a significant challenge. The addition of crushed rubber to asphalt binder not only can improve the performance of asphalt mixtures but also is an effective and environmentally friendly way to recycle scrapped tires. However, rubber asphalt mixtures demand higher production temperatures than conventional asphalt binders due to the higher viscosity of asphalt rubber binder. The main objective of this study is to evaluate the rheological properties of rubber‐modified asphalt by adding polyamide 6 and investigate the modification mechanism of crumb rubber‐modified asphalt (CRMA) after adding polyamide 6. To this end, the content of waste rubber in the prepared rubber asphalt was 20%. The conventional laboratory rheological tests were employed to evaluate the performance of crumb rubber‐modified asphalt after adding polyamide 6. Furthermore, to investigate the interaction mechanism of crumb rubber and asphalt, a series of advanced tools, including the scanning electron microscopy (SEM) test, differential scanning calorimeter (DSC) test, and Fourier transform infrared spectroscopy (FTIR) test, were conducted. From the experimental results obtained, it may be concluded that crumb rubber‐modified asphalt with adding polyamide 6 not only improves the engineering properties of the rubber‐modified asphalt but also improves the performance of rubber asphalt. From the FTIR and SEM tests, it is concluded that there is no new functional group in the mixing process of crumb rubber and the asphalt, which contributes to the storage stability of asphalt binder and runway.
Short-term load forecasting with using multiple linear regression
Authors: Dhaval Bhatti , Deshpande Anuradha
Published: June 2020

In this paper short term load forecasting (STLF) is done with using multiple linear regression (MLR). A day ahead load forecasting is obtained in this paper. Regression coefficients were found out with the help of method of least square estimation. Load in electrical power system is dependent on temperature, due point and seasons and also load has correlation to the previous load consumption (Historical data). So the input variables are temperature, due point, load of prior day, hours, and load of prior week. To validate the model or check the accuracy of the model mean absolute percentage error is used and R squared is checked which is shown in result section. Using day ahead forecasted data weekly forecast is also obtained.
Solar assisted cooling rule in indoor air quality
Authors: Baniyounes Ali M. , Ghadi Yazeed Y.
Published: June 2020

Indoor air quality as always is the centre of attention for researchers, architect developers and public health officials. As every-one know. The human exposure to a variety of indoor pollutants and the high cost of energy are the motivation for these kinds of studies. Fungus and mould growth has always been a problem in subtropical climate areas due to the high temperature and high humidity. Generally in institutional buildings, most of the internal heat load is generated by human body and thermal comfort is achieved with   extensive usage of recycled air and air conditioning. The main considerations in any air conditioning system economisers are based on the usage of recycled air and air ventilation. The current practice in an institutional building cooling system under subtropical climate is to curb the mould issue by overcooling large recirculation airflow to remove the moisture content from the air, which is considered as an expensive practice. The use of a solar desiccant cooling system to reduce moisture from the air and to improve indoor air quality is found to be economical, environmental friendly and readily achievable in the tropics. This technology is the future alternative to the conventional vapour compression cooling system to maintain human thermal comfort conditions and enhance indoor air quality. Solar desiccant cooling systems are also environmentally friendly and energy efficient. This paper presents review on a solar desiccant cooling system and its effect on indoor air quality. It first introduces the issue of air moisture, mould growth and indoor air quality and then the development and application of thermally activated desiccant cooling technologies.
Dual output DC-DC quasi impedance source converter
Authors: Ado Muhammad , Jusoh Awang , Sutikno Tole , Muda Mohd Hanipah , Arfeen Zeeshan Ahmad
Published: June 2020

A double output port DC-DC quasi impedance source converter (q-ZSC) is proposed. Each of the outputs has a different voltage gain. One of the outputs is capable of bidirectional (four-quadrant) operation by only varying the duty ratio. The second output has the gain of traditional two-switch buck-boost converter. Operation of the converter was verified by simulating its responses for different input voltages and duty ratios using MATLAB SIMULINK software. Its average steady-state output current and voltage values were determined and used to determine the ripples that existed. These ripples are less than 5% of the average steady-state values for all the input voltage and duty ratio ranges considered.
Review of high-speed phase accumulator for direct digital frequency synthesizer
Authors: Abbas Abdulkareem Dawah
Published: June 2020

A review of high-speed pipelined phase accumulator (PA) is proposed in this paper. The detail explanation of ideas, methods and techniques used in previous researches to improve the PA throughput designs were surveyed. The Brent–Kung (BK) adder was modified in this paper to be applied in pipelined PA architecture. A comparison of different adder circuits, includes a modified BK, ripple carry adder (RCA), Kogge-Stone adder (KS) and other prefix adders were applied to architect the PA based on Pipeline technique. The presented pipelined PA design circuit with multiple frequency control word (FCW) and different adders were coded Verilog hardware description language (HDL) code, compiled and verified with field programmable gate array (FPGA) kit platform. The comparison result shows that the modified BK adder has fast performances. The shifted clocking technique is utilized in the proposed pipelined PA circuit to reduce the unwanted repetitive D-flip flop (DFF) registers (coming from the pipeline technique), while preserving the high speed.
A new structure of a wide band bridge power limiter
Authors: Echchakhaoui Khalifa , Abdelmounim Elhassane , Zbitou Jamal , Bennis Hamid
Published: June 2020

In this work, new design and simulation of a microstrip power limiter based on Schottky diode is presented. The proposed circuit is a zero bias power limiter built by associating a transmission line in parallel to a four Schottky rectifier bridge circuit. The first circuit using a single stage rectifier is analyzed and simulated. To improve this single stage, a second and final limiter is designed with two stages rectifier. Simulation results for the final circuit show an ideal limiter behavior and good performance of limiting rate up to 20dB for a threshold input power varying from 5 dBm to 30 dBm. While insertion loss remains low at small signal.
Test platform for electronic control units of high-performance safety-critical multi actuator systems
Authors: Bucci Giovanni , Ciancetta Fabrizio , Fiorucci Edoardo , Mari Simone
Published: June 2020

In this paper we are mostly concerned with the problem of testing electronic control units of synchronized electric power actuators. This task is particularly complex for safety critical applications, where it is crucial that the control system properly reacts in response to the faults, that are hard to reproduce and verify. A cost-effective flexible and reconfigurable test platform is proposed, discussing its architecture and implementation. The proposed system facilitates the phase of definition and development of the electronic control unit, allowing the interfacing towards both hydraulic and electromechanical actuators, and having a high flexibility as regards the I/O signals. Some results, obtained during the laboratory test activity, are also presented.
Analytical framework for optimized feature extraction for upgrading occupancy sensing performance
Authors: Mane Preethi Krishna Rao , Rao K. Narasimha
Published: June 2020

The adoption of the occupancy sensors has become an inevitable in commercial and non-commercial security devices, owing to their proficiency in the energy management. It has been found that the usages of conventional sensors is shrouded with operational problems, hence the use of the Doppler radar offers better mitigation of such problems. However, the usage of Doppler radar towards occupancy sensing in existing system is found to be very much in infancy stage. Moreover, the performance of monitoring using Doppler radar is yet to be improved more. Therefore, this paper introduces a simplified framework for enriching the event sensing performance by efficient selection of minimal robust attributes using Doppler radar. Adoption of analytical methodology has been carried out to find that different machine learning approaches could be further used for improving the accuracy performance for the feature that has been extracted in the proposed system of occuancy system.
Lumbar disk 3D modeling from limited number of MRI axial slices
Authors: Al-Mnayyis Asma’a , Alasal Sanaa Abu , Alsmirat Mohammad , Baker Qanita Bani , AlZu’bi Shadi
Published: June 2020

This paper studies the problem of clinical MRI analysis in the field of lumbar intervertebral disk herniation diagnosis. It discusses the possibility of assisting radiologists in reading the patients MRI images by constructing a 3D model for the region of interest using simple computer vision methods. We use axial MRI slices of the lumbar area. The proposed framework works with a very small number of MRI slices and goes through three main stages. Namely, the region of interest extraction and enhancement, inter-slice interpolation, and 3D model construction. We use the Marching Cubes algorithm to construct the 3D model of the the region of interest. The validation of our 3D models is based on a radiologist’s analysis of the models. We tested the proposed 3D model construction on 83 cases and We have a 95% accuracy according to the radiologist evaluation. This study shows that 3D model construction can greatly ease the task of the radiologist which enhances the working experience. This leads eventually to more accurate and easy diagnosis process.
Computational scrutiny of image denoising method found on DBAMF under SPN surrounding
Authors: Patanavijit Vorapoj
Published: June 2020

Traditionally, rank order absolute difference (ROAD) has a great similarity capacity for identifying whether the pixel is SPN or noiseless because statistical characteristic of ROAD is desired for a noise identifying objective. As a result, the decision based adaptive median filter (DBAMF) that is found on ROAD technique has been initially proposed for eliminating an impulsive noise since 2010. Consequently, this analyzed report focuses to examine the similarity capacity of denoising method found on DBAMF for diverse SPN Surrounding. In order to examine the denoising capacity and its obstruction of the denoising method found on DBAMF, the four original digital images, comprised of Airplane, Pepper, Girl and Lena, are examined in these computational simulation for SPN surrounding by initially contaminating the SPN with diverse intensity. Later, all contaminated digital images are denoised by the denoising method found on DBAMF. In addition, the proposed denoised image, which is computed by this DBAMF denoising method, is confronted with the other denoised images, which is computed by Standard median filter (SMF), Gaussian Filter and Adaptive median filter (AMF) for demonstrating the DBAMF capacity under subjective measurement aspect.
Energy efficient power control for device to device communication in 5G networks
Authors: Charar Mohamed Amine , Guennoun Zouhair
Published: June 2020

Next generation cellular networks require high capacity, enhanced energy efficiency and guaranteed quality of service (QoS). In order to meet these targets, device-to device (D2D) communication is being considered for future 5th generation especially for certain applications that require the proximity gain, the reuse gain, and the hop gain. In this paper, we investigate energy efficient power control for the uplink of an OFDMA (orthogonal frequency-division multiple access) single-cell communication system composed of both regular cellular users and device to device (D2D) pairs. Firstly, we analyze and mathematically model the actual requirements forD2D communications and traditional cellular links in terms of minimum rate and maximum power requirement. Secondly, we use fractional programming in order to transform the original problem into an equivalent concave one and we use the non-cooperative Game theory in order to characterize the equilibrium. Then, the solution of the game is given as a water-filling power allocation. Furthermore, we implement a distributed power allocation scheme using three ways: a) Fractional programming techniques b) Closed form expression (the novelty is the use of wright omega function). c) Inverse water filling. Finally, simulations in both static and dynamic channel setting are presented to illustrate the improved performance in term of EE, SE (spectral efficiency) and time of execution of the iterative algorithm (Dinkelbach) than the closed form algorithms.
A steepest descent algorithm for the optimal control of a cascaded hydropower system
Authors: Ogunbiyi Olalekan , Thomas Cornelius T. , Ogundepo Oludare Y. , Omeiza Isaac O. A. , Akanni Jimoh , Olufeagba B. J.
Published: June 2020

Optimal power generation along the cascaded Kainji-Jebba hydroelectric power system had been very difficult to achieve. The reservoirs operating heads are being affected by possible variation in impoundments upstream, stochastic factors that are weather-related, availability of the turbo-alternators and power generated at any time. Proposed in this paper, is an algorithm for solving the optimal release of water on the cascaded hydropower system based on steepest descent method. The uniqueness of this work is the conversion of the infinite dimensional control problem to a finite one, the introduction of clever techniques for choosing the steepest descent step size in each iteration and the nonlinear penalty embedded in the procedure. The control algorithm was implemented in an Excel VBA® environment to solve the ormulated Lagrange problem within an accuracy of 0.03%. It is recommended for use in system studies and control design for the optimal power generation in the cascaded hydropower system.
The students’ acceptance of learning management systems in Saudi Arabian Universities
Authors: Alsmadi Mutasem K.
Published: June 2020

For distance learners, continuous official education is very important for improving knowledge and learning experience in order to meet the career challenges in the modern world. This work studies the success factors which affect the use of LMS and evaluates the ability to apply the proposed model in the field of distance learning (DL) particularly in higher education. The survey was carried out on higher education learners who were included in the DL instructions. This work has utilized a questionnaire that was modified from literature to inspect three measurements, system design, system usage, and system outcome. Utilizing the obtained survey data for students of DL (N=149), the path analysis discovered that the design of the system has a significant effect on the satisfaction of users and intention for using LMS which affects the use of the system. Consequently, the satisfaction of users and the system used has a great impact on the net benefit.
Energy efficient chaotic whale optimization technique for data gathering in wireless sensor network
Authors: R. Sridhar , Guruprasad N.
Published: June 2020

A Wireless Sensor Network includes the distributed sensor nodes using limited energy, to monitor the physical environments and forward to the sink node. Energy is the major resource in WSN for increasing the network lifetime. Several works have been done in this field but the energy efficient data gathering is still not improved. In order to amend the data gathering with minimal energy consumption, an efficient technique called chaotic whale metaheuristic energy optimized data gathering (CWMEODG) is introduced. The mathematical model called Chaotic tent map is applied to the parameters used in the CWMEODG technique for finding the global optimum solution and fast convergence rate. Simulation of the proposed CWMEODG technique is performed with different parameters such as energy consumption, data packet delivery ratio, data packet loss ratio and delay with deference to dedicated quantity of sensor nodes and number of packets. The consequences discussion shows that the CWMEODG technique progresses the data gathering and network lifetime with minimum delay as well as packet loss than the state-of-the-art methods.
Design an active verification mechanism for certificates revocation in OCSP for internet authentication
Authors: Mahmmod Khalid Fazaa , Azeez Mohammed Muzahem , Ismael Zeyad Hashem
Published: June 2020

No doubt that data security online is crucial. Therefore, great attention has been paid to that aspect by companies and organizations given its economic and social implications. Thus, online certificate status protocol (OCSP) is considered one of the most prominent protocol functioning in this field, which offers a prompt support for certificates online. In this research, a model designed based on field programable gate array (FPGA) using Merkel’s tree has been proposed to overcome the delay that might have occurred in sorting and authentication of certificates. Having adopted this model and with the assistance of Hash function algorithm, more than 50% of certificates have been processed in comparison with standard protocol. Moreover, certificates have been provided with substantial storage space with high throughput. Basically, Hash function algorithm has been designed to arrange and specify a site of verified or denied certificates within time of validity to protect servers from intrusion and clients from using applications with harmful contents.
Evaluation of phase-frequency instability when processing complex radar signals
Authors: Boiko Juliy , Karpova Lesya , Eromenko Oleksander , Havrylko Yevhen
Published: June 2020

A new radar system for digital signal processing before detection is proposed. These are the guidelines for selecting an intermediate frequency for signal processing. The features of signal processing in the case of echo-signal selection by the features of the correlation properties of their complex bypass are described. This paper presents the study of ambiguity function (AF) when processing complex radar signals. In this work, the AF synthesis was performed considering non-determined components and the presence of phase-frequency instability. The received result enhances the potentials for distinguishing an incoherent radar signal. The numerical simulation results of received AF are presented. Considering fluctuation components in the complex AF, depending on the laws of the distribution of amplitude and frequency fluctuations and their parameters, allowed to get the gain in the width of the main lobe from the units to tens of times. Paper represents original analytical expressions for AF of radio-signals modulated by narrow band random processes with various distribution laws.
Energy cost savings based on the UPS
Authors: Tin Phu Tran , Ha Duy Hung , Tran Minh , Vu Quang Sy
Published: June 2020

Energy-saving, improving energy efficiency, and finding a new efficient way to use energy are considered as an urgent problem in over the world. In this paper, we consider the economics of energy use in combination with energy storage units where two forms of electricity exist in the power system. Then the problem of optimizing the installation capacity (to optimize the investment costs for energy storage) is presented and investigated in connection with the conversion systems. The topic opens a very significant result, including the introduction of a mathematical model to calculate the simulation in optimizing the installation capacity of the equipment in the system, multi-source power, as well as voltage and power stability benefits.
Electromagnetic pollution maps as a resource for assessing the risk of emissions from mobile communications antennas
Authors: Garces-Gomez Yeison Alberto , Henao-Cespedes Vladimir , Diaz-Cadavid Luis Fernando
Published: June 2020

Electromagnetic pollution has taken on importance in recent decades, as interest is growing in knowing how the proliferation of mobile communication devices can affect the environment and generate health problems in the population. In this document, a systematic review of the methodologies for measuring electromagnetic radiation is carried out with a view to generating pollution profiles. It also develops a novel methodology for measuring electromagnetic pollution (EMP) in urban areas, and is validated with a case study using a map of EMP in the city of Manizales (Colombia), determining the spatial distribution of radiation levels. In order to generate the map, EMP measurements were carried out in the bands of local mobile telephone operators, in addition to the LPWAN (low power wide area network) LoRaWAN and Sigfox networks, Wi-Fi, and those related to IoT technologies.