High-voltage pulse generator based on sequentially charged MMC-SMs operating in a voltage-boost mode

Pulse forming networks and Marx generators are the classical rectangular waveform pulse generators (PGs). They are inflexible and their capacitors must be fully charged to the required voltage from 0V before delivering each high-voltage (HV) pulse. They are only able to generate unipolar pulses; if bipolar pulses are sought another generator fed from a negative supply voltage is added. Recently, several power electronics based PGs have been proposed. This paper presents an HV power electronics based PG, which is based on Half-Bridge Modular Multilevel Converter (HB-MMC) sub-modules (SMs) charged sequentially in a voltage boost mode. Each SM capacitor and main switch form a boost converter with the charging input supply and inductor. As a result, all SM capacitors are charged to a voltage greater than the input. During the discharging process the SM capacitors are connected in series, producing a rectangular HV pulse across the load. The proposed charging method allows a reduction in the converter footprint in comparison with recently proposed MMC sequentially charged PG topologies. Although only rectangular pulse waveforms are sought in this paper, a SM capacitor voltage balance method allows multilevel pulse generation. The viability of the proposed converter is confirmed by MATLAB/Simulink simulation and scaled-down experimentation

BLOOM: A 176B-Parameter Open-Access Multilingual Language Model

Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License

Numerical study of a novel ventilation system added to the structure of a catamaran for different slamming conditions using OpenFOAM

Large-size catamarans' structural behavior is sensitive and critical during the slamming phenomenon. “Ventilation pipes” within the center bow structure are proposed to discharge these cumulative pressure and related loads. The validation case is comprising two different simulation schemes, static and dynamic wedge. First, the appropriate method is chosen based on the accuracy and needed computational running time criteria. The numerical solution approach solves the RANS equation using the Open Field Operation and Manipulation (OpenFOAM) library called “InterFoam and OverInterDyMFoam for static and dynamic mesh respectively. Totally three different impact conditions with four different impact velocities (12 case studies) were considered for the case with added ventilation pipes (amended hull) and the standard model (parent-hull). Apart from the limitation of the proposed plan which is discussed, the results indicate that the recorded pressure and total force decreases by about (15%–50%), and (5%–25%) respectively

Oxidative Stress Tolerance by Calcium and Histidine in Two Tomato Cultivars Under Nickel Stress

We investigated calcium (Ca) and L-histidine (His) interaction on nickel (Ni)-induced oxidative stress tolerance in two tomato (Solanum lycopersicum Mill.) cultivars including Cal-J N3 and Petoearly CH. CaCl2 (0 and 300 µM) and L-histidine (0 and 300 µM) effects on the oxidative responses in these cultivars cultured were compared in the hydroponic media under Ni stress (NiSO4; 0,150 and 300 µM). The activities of antioxidative enzymes including catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total content of proteins, malondialdehyde (MDA), other aldehydes, H2O2, Ca2+, Ni2+, ascorbate (ASC), dehydroascorbate (DHA) and electrolytes leakage (EL) were determined. The obtained results indicated that the application of Ca and His generally reduced oxidative markers such as the contents of EL, H2O2, MDA and activity of CAT as well as the Ni2+content of root and shoot organs under nickel toxicity, while application of Ni treatment without Ca+His increased these oxidative parameters and accumulation of Ni2+, compared to the control. Applying Ni without Ca and His has resulted in reduction of GPX, APX and SOD activities as well as concentrations of root and shoot Ca2+and ASC in the two mentioned cultivars. Application of Ca and His lead to the elevated contents of Ca2+ and ASC, increased activities of GPX, APX and SOD as well as inhibition of Ni2+ accumulation differently in both cultivars. Ca and His also alleviated the adverse effects of Ni stress on the selected investigated parameters especially in Petoearly CH cultivar. Thus, interaction of Ca and His appeared to improve adaptive responses to Ni stress leading to decreasing Ni-induced oxidative stress in the tomato plants. Therefore, our results suggest that Ca+His alleviated nickel-induced oxidative stress by uptake and inhibition of translocation of Ni2+ plus Ni chelating mechanism improvement in the tomato cultivars

Food Samples

Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sensitive sensor for the professional quantitative determination of sudan I in food samples in aqueous solution. In the first step, CdO/NPs synthesis using chemical precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The propose sensor shows a better electrochemical response with lower over-potential and high sensitivity for sudan I compared with unmodified carbon paste electrode using linear sweep voltammetry (LSV). The electro-oxidation of sudan I occurred in a pH-dependent e(-) and H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions in square wave voltammetry (SWV), the voltammetric oxidation peak current of sudan I showed linear dynamic ranges with a detection limit of 0.05 mu M for sudan I. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory result

Characterization of Leishmania Parasites Isolated From Kala- azar Patients in Kohgiloyeh and Boyerahmad, Using Semi-Nested PCR

ABSTRACT: Introduction & Objective: Visceral leishmaniasis (VL) is a disease commonly known as Kala-azar caused by protozoan parasites of the genus Leishmania including L. donovani, L. infantum and L. chagasi. VL is sporadic in many areas of Iran and is endemic in a few provinces such as Fars, Azarbayjan, Bushehr, Ardabil and Qom. VL has been reported from some areas of Kohgiloyeh and Boyerahmad and this study aimed to characterize the causative agent of VL in this region. Materials & Methods: Bone marrow sample was obtained from 6 VL patients from children department in Imam Sajad hospital in Yasuj. DNA was extracted from the obtained samples and was checked by semi-nested PCR to determine the species of the parasite. To do that, a segment of minicircle kinetoplast DNA was amplified, using LINR4 and LIN17 primers. Products of PCR were evaluated by electrophoresis, using 1.5% agarose and stained with ethidium bromide. Results: Parasitologically examination of bone marrow smears demonstrated amastigotes form of the parasite in the samples. For mass cultivation, isolated parasites were cultured in diphasic NNN followed by RPMI 1640 media. All the samples produced a 720 bp band in PCR assay. The isolates were compared with referent strains and it was revealed that all the isolates were L. infantum. Conclusion: Findings of this study demonstrated that the causative agent of VL in Kohgiloyeh and Boyerahmad was L. infantum. Further study is needed to explore other aspects of VL in this region

Food Samples

Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sensitive sensor for the professional quantitative determination of sudan I in food samples in aqueous solution. In the first step, CdO/NPs synthesis using chemical precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The propose sensor shows a better electrochemical response with lower over-potential and high sensitivity for sudan I compared with unmodified carbon paste electrode using linear sweep voltammetry (LSV). The electro-oxidation of sudan I occurred in a pH-dependent e(-) and H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions in square wave voltammetry (SWV), the voltammetric oxidation peak current of sudan I showed linear dynamic ranges with a detection limit of 0.05 mu M for sudan I. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory result

Voltammetric nanostructure based sensor for determination of Sudan I in food samples

Ionic liquid/CdO/NPs carbon paste electrode (IL/CdO/NPs/CPE) has been used as a high sensitive sensor for the professional quantitative determination of sudan I in food samples in aqueous solution. In the first step, CdO/NPs synthesis using chemical precipitation method and characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The propose sensor shows a better electrochemical response with lower over-potential and high sensitivity for sudan I compared with unmodified carbon paste electrode using linear sweep voltammetry (LSV). The electro-oxidation of sudan I occurred in a pH-dependent e- and H+ process, and the electrode reaction followed a diffusion-controlled pathway. Under the optimum conditions in square wave voltammetry (SWV), the voltammetric oxidation peak current of sudan I showed linear dynamic ranges with a detection limit of 0.05 μM for sudan I. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory result. © 2015 The Authors