A New Symmetric/Asymmetric Multilevel Inverter Based on Cascaded Connection of Sub-Multilevel Units Aiming less Switching Components and Total Blocked Voltage

In this paper, a new multilevel inverter is designed to improve the power and voltage quality, which contains a lesser number of switches in the specified voltage levels. The proposed inverter includes power electronic devices such as switches and diode, and DC inputs. In the proposed structure the desired output voltage can be produced by considering a series connection of a novel sub-multilevel module. This structure can be designed in both the symmetric and asymmetric topologies. The proposed structure has superior condition in terms of semiconductor switches and drivers count as well as switching loss. Additionally, the Total Blocked Voltage (TBV) of the proposed converter is compared with the conventional and the novel converters. This topology is studied by symmetric as well as asymmetric topologies through simulations in Matlab/Simulink environment as well as experiments by a laboratory prototype

A new look into the impacts of dust radiative effects on the energetics of tropical easterly waves

Saharan dust aerosols are often embedded in tropical easterly waves, also known as African easterly waves, and are transported thousands of kilometers across the tropical Atlantic Ocean, reaching the Caribbean Sea, Amazon Basin, and eastern USA. However, due to the complex climate dynamics of west Africa and the eastern tropical Atlantic Ocean, there is still a lack of understanding of how dust particles may influence the development of African easterly waves, which are coupled to deep convective systems over the tropical Atlantic Ocean and in some cases may seed the growth of tropical cyclones. Here we used 22 years of daily satellite observations and reanalysis data to explore the relationships between dust in the Saharan air layer and the development of African easterly waves. Our findings show that dust aerosols not merely are transported by the African easterly jet and the African easterly waves system across the tropical Atlantic Ocean, but also contribute to the changes in the eddy energetics of the African easterly waves. The efficiency of the dust radiative effect in the atmosphere is estimated to be a warming of approximately 20 W m−2 over the ocean and 35 W m−2 over land. This diabatic heating of dust aerosols in the Saharan air layer acts as an additional energy source to increase the growth of the waves. The enhanced diabatic heating of dust leads to an increase in meridional temperature gradients in the baroclinic zone, where eddies extract available potential energy from the mean flow and convert it to eddy kinetic energy. This suggests that diabatic heating of dust aerosols can increase the eddy kinetic energy of the African easterly waves and enhance the baroclinicity of the region. Our findings also show that dust outbreaks over the tropical Atlantic Ocean precede the development of baroclinic waves downstream of the African easterly jet, which suggests that the dust radiative effect has the capability to trigger the generation of the zonal and meridional transient eddies in the system comprising the African easterly jet and African easterly waves.</p

Effect of substrate grain size on structural and corrosion properties of electrodeposited nickel layer protected with self-assembled film of stearic acid

In the present study, the impact of copper substrate grain size on the structure of the succeeding electrodeposited nickel film and its consequent corrosion resistance in 3.5% NaCl medium were evaluated before and after functionalization with stearic acid. Nickel layers were electrodeposited on two different copper sheets with average grain size of 12 and 25 \u3bcm, followed by deposition of stearic acid film through self-assembly. X-ray diffraction analysis of the electrodeposited nickel films revealed that the deposition of nickel film on the Cu substrate with small (12 \u3bcm) and large (25 \u3bcm) grains is predominantly governed by growth in the (220) and (111) planes, respectively. Both electrodeposited films initially exhibited a hydrophilic nature, with water-contact angles of 56\ub0 and <10\ub0, respectively. After functionalization with stearic acid, superhydrophobic films with contact angles of ~150\ub0 were obtained on both samples. In a 3.5% NaCl medium, the corrosion resistance of the nickel layer electrodeposited on the copper substrate with 25 \u3bcm grains was three times greater than that deposited on the copper substrate with 12 \u3bcm grains. After functionalization, the corrosion resistance of both films was greatly improved in both short and long immersion times in 3.5% NaCl medium

Insights into galvanic corrosion behavior of Ti-Cu dissimilar joint: Effect of microstructure and volta potential

The effect of microstructure on corrosion behavior of a solid-state explosion welded Ti-Cu bimetal is investigated by means of alternating current-direct current (AC-DC) electrochemical measurements, optical microscopy, scanning electron microscopy, and scanning Kelvin probe force microscopy (SKPFM). The results indicate that the titanium regions in the welding interface, local melted zone (LMZ), and LMZ-Cu interface are potential sites for initiation of corrosion attacks. SKPFM mapping clearly shows that before exposure of the sample to a 3.5% NaCl corrosive solution and at the beginning of the exposure, the Cu side of the bimetal has a higher Volta potential in comparison to that of the Ti region, and thus acts as a cathode. Electrochemical measurements also confirm that titanium acts as an anode and copper as a cathode, in the first moments of immersion, in accordance with macroscopic observations and SKPFM results. However, by growing a passive layer of titanium oxide and titanium hydroxide on the Ti side after about 1 h exposure to the corrosive medium, the titanium side becomes nobler and the polarity arrangement in the galvanic couple reverses

The Relationship Between Serum Levels of Interleukins 6, 8, 10 and Clinical Outcome in Patients With Severe Traumatic Brain Injury

Background: Clinical outcome in patients with severe traumatic brain injury (TBI) depends on both primary and secondary brain injuries. Neuroinflammation is an important secondary mechanism, which occurs by releasing interleukins (ILs). Increased levels of ILs may affect clinical outcome following TBI. Objectives: This study aimed to determine the relationship between the serum levels of interleukins 6, 8 and 10 and clinical outcome in patients with severe TBI 6 months after injury. Patients and Methods: In a descriptive-analytical study, 44 patients with GCS ≤ 8 (Glasgow coma scale) and age ≥ 14 years were included. Their blood samples were collected at first 6 hours after injury. Clinical outcome was determined based on GOS (Glasgow Outcome Scale) at 6 months after head injury. Serum levels of interleukins 6, 8 and 10 were measured using the ELISA method. Spearman's rho, independent T-Test, and Mann-Whitney Test were used for data analysis. Results: Comparing the serum levels of interleukins in two groups with favorable and unfavorable clinical outcomes showed that the mean serum levels of interleukins 6 and 8 in group with favorable outcome was 85.2 ± 51.6 and 52.2 ± 31.9, respectively lower than those of group with unfavorable outcome with 162.3 ± 141.1 and 173.6 ± 257.3 (P < 0.03) and (P < 0.01). Conclusions: Increased serum levels of interleukins 6 and 8 as a predictive marker might be associated with unfavorable clinical outcome in patients with severe TBI

Protein interaction network of Arabidopsis thaliana female gametophyte development identifies novel proteins and relations

Although the female gametophyte in angiosperms consists of just seven cells, it has a complex biological network. In this study, female gametophyte microarray data from Arabidopsis thaliana were integrated into the Arabidopsis interactome database to generate a putative interaction map of the female gametophyte development including proteome map based on biological processes and molecular functions of proteins. Biological and functional groups as well as topological characteristics of the network were investigated by analyzing phytohormones, plant defense, cell death, transporters, regulatory factors, and hydrolases. This approach led to the prediction of critical members and bottlenecks of the network. Seventy-four and 24 upregulated genes as well as 171 and 3 downregulated genes were identified in subtracted networks based on biological processes and molecular function respectively, including novel genes such as the pathogenesis-related protein 4, ER type Ca2+ ATPase 3, dihydroflavonol reductase, and ATP disulfate isomerase. Biologically important relationships between genes, critical nodes, and new essential proteins such as AT1G26830, AT5G20850, CYP74A, AT1G42396, PR4 and MEA were found in the interactome’s network. The positions of novel genes, both upregulated and downregulated, and their relationships with biological pathways, in particular phytohormones, were highlighted in this study.Batool Hosseinpour, Vahid HajiHoseini, Rafieh Kashfi, Esmaeil Ebrahimie and Farhid Hemmatzade

Effects of right hepatic artery ligation

Abstract Background: Injury to right hepatic artery (RHA) may occur during hepatobiliary operative procedures. Although it may not be detected and is clinically silent in most of the cases, liver abscess, bleeding, hemobilia, and right hepatic lobe ischemia needing surgical excision have been reported. The aim of this study was a more detailed evaluation of hepatic consequences following RHA injury in an animal model. Methods: This study was conducted on 20 New Zealand rabbits 6 months of age. Blood samples for the measurement of hepatic enzymes was obtained from the rabbits before ligation of the hepatic artery. After 10 days, blood sampling was repeated and the animals were killed and 0.5 × 2 cm liver wedge biopsy was prepared from right lateral lobe, the distribution area of RHA. P values of < 0.05 were considered significant. Results: Laboratory data before and after surgical intervention showed serum bilirubin of 0.133 ± 0.044 and 0.135 ± 0.042, respectively (P value = 0.47). Serum alkaline phosphatase (ALP) was 122.4 ± 44.12 and 122.8 ± 44.43, (P value = 0.36) respectively. Serum glutamic-pyruvic transaminase (SGPT) was 31.2 ± 5.34 and 86.2 ± 33.9, (P value = 0.001) respectively. Serum glutamic oxaloacetic transaminase (SGOT) was 30.13±8.46 and 69.4±47.7, respectively (P value = 0.001). Laparotomy showed no considerable change in median lobe of livers, except mild necrosis in one (5%) rabbit. Severe necrosis was found in the right lateral lobe of 15 rabbits (75%), moderate necrosis in 3 (15%), and mild necrosis in 2 (10%) cases. No abscess or gangrene was found. The Gall bladder was intact in all animals. Conclusions: The RHA obliteration causes an increase in liver enzymes and considerable right lateral hepatic lobe necrosis (75%) but no liver abscess, gangrene or gall bladder abnormality. © 2017, Trauma Monthly

Right pulmonary artery occlusion by an acute dissecting aneurysm of the ascending aorta

We describe the case of a 76-year old female who presented with a Type A aortic dissection requiring repair with an interposition graft and aortic valve replacement. Post-operatively she had clinical features and computerised tomographic images suggestive of a pulmonary embolus and died 24 hours later. The extremely rare finding of intramural thrombus occluding the right pulmonary artery was seen at post mortem

Microbial fuel cells: a green and alternative source for bioenergy production

Microbial fuel cell (MFC) represents one of the green technologies for the production of bioenergy. MFCs using microalgae produce bioenergy by converting solar energy into electrical energy as a function of metabolic and anabolic pathways of the cells. In the MFCs with bacteria, bioenergy is generated as a result of the organic substrate oxidation. MFCs have received high attention from researchers in the last years due to the simplicity of the process, the absence in toxic by-products, and low requirements for the algae growth. Many studies have been conducted on MFC and investigated the factors affecting the MFC performance. In the current chapter, the performance of MFC in producing bioenergy as well as the factors which influence the efficacy of MFCs is discussed. It appears that the main factors affecting MFC’s performance include bacterial and algae species, pH, temperature, salinity, substrate, mechanism of electron transfer in an anodic chamber, electrodes materials, surface area, and electron acceptor in a cathodic chamber. These factors are becoming more influential and might lead to overproduction of bioenergy when they are optimized using response surface methodology (RSM)