One-pot three-component synthesis of some novel ethyl 3-alkyl-2-thioxo-2,3-dihydrothiazole-4-carboxylates under solvent- and catalyst-free conditions at room temperature

A green and efficient one-pot three-component synthesis of some novel ethyl 3-alkyl-2-thioxo-2,3-dihydrothiazole-4-carboxylates from the reaction of primary alkyl or benzyl amines, carbon disulfide and ethyl bromopyruvate is introduced. This straightforward technique gave the looked-for products in high yields during 1.5–3?h without need for catalyst or solvent assistance.     

Large distance flow-slide at Jono-Oge due to the 2018 Sulawesi Earthquake,Indonesia

There was a shallow earthquake in the Central Sulawesi province of Sulawesi island of Indonesia with a moment magnitude (Mw) 7.5 on 28th September 2018 at 18:02:44 local time. The event was preceded by major foreshocks and followed by aftershocks of significant magnitude. The epicenter of the main shock was in the Donggala regency of Minahasa peninsula of Central Sulawesi, approximately 70 km from the provincial capital of Palu. The earthquake was caused by the tectonic movement of the left lateral Palu- Koro fault within the Molucca Sea microplate, triggering major geotechnical failure and structural damage in Palu city and Sigi regency. Thousands of people died or are still unaccounted for, and countless others were injured. Balaroa, Petobo, Jono-Oge and Sibalaya were the worst hit mainly due to large-scale flow-slides and mud flows. It was the first time that such large-scale flow failures were triggered by an earthquake, and that the failure of very gentle sloping ground swept away whole localities. The objective of this research was to provide insight into the scale of ground failure and other infrastructural damage caused by the event, especially in Jono-Oge area, where the flow distance was longest. The authors performed preliminary and detailed surveys in the area twice by conducting Portable Dynamics Cone Penetration Test (PDCPT), collecting disturbed and undisturbed samples and using aerial drone (UAV) photography. The findings of the reconnaissance survey are described here along with subsequent data interpretation. Finally, the mechanism of the flow-slides is discussed.     

Seasonal variation of aflatoxin M1 contamination in industrial and traditional Iranian dairy products

This study aimed to determine the occurrence of aflatoxin M₁ (AFM₁) contamination in 682 dairy product samples consisting of raw milk of cow, goat and sheep; Lighvan cheese; and industrial and traditional yoghurt, Kashk and Doogh samples collected from popular markets and dairy ranches in four large Iranian cities. Thin layer chromatography (TLC) technique was used for analysis of the samples. Results showed that the incidence and levels of AFM₁ contamination in raw cow milk and industrial products (manufactured from cow milk) were higher than raw goat or sheep milk, and traditional products (made from goat and sheep milk), respectively. Moreover, seasonal variations influenced the concentration of AFM₁ in most of the analyzed dairy products. Owing to the abundance and popularity of the industrial products, contamination of these products in such a level could be a potential hazard for public health.     

Numerical analysis reliability control for a double‐pipe heat exchanger with virtual entropy generation method

There are two primary laws including the first and second laws of thermodynamics that should be used to assess a process. Generally, only the first law of thermodynamics is investigated in numerical solutions, so it is possible to exist some numerical results that do not satisfy the second law of thermodynamics because of numerical errors. To achieve reliable numerical outcomes, it is better to apply two indexes of HEAT BALANCE ERROR and VIRTUAL ENTROPY GENERATION, which come from the second law of thermodynamics. In other words, an approach to develop computational fluid dynamics investigations is to take second law of thermodynamics into consideration. In this study, two different models including counterflow double‐pipe heat exchanger and single‐pipe with constant wall temperature are simulated in various cases with different efficiencies and temperature ratios. It is found that 46 cases of total 523 double‐pipe models and 24 cases of total 402 simulations of single‐pipe models had unacceptable results regarding to two mentioned criteria. The results revealed that it is less likely to gain unreliable results in smaller efficiency and lower inlet temperature for double‐pipe heat exchanger and single‐pipe respectively.     

Prevalence of parasitic contamination in vegetables used for raw consumption in Shahrekord, Iran: Influence of season and washing procedure

This study aimed to determine the prevalence of intestinal parasites in raw vegetables consumed in Shahrekord, Iran; and efficacy of season and washing procedures to remove parasites from the vegetables. A total of 304 field vegetable samples composed of parsley, spearmint, scallion, basil, coriander, dill, cress, leek, tarragon, radish and purslane were purchased from the vegetable markets. Each sample was divided into three groups. One group was used as the unwashed sample and the second and third groups were washed with traditional and standard washing procedures, respectively. Intestinal parasites were detected in 32.6% of unwashed, 1.3% of traditionally washed and not in any standard washed samples (P < 0.001). The parasites were detected in unwashed vegetable samples included Ascaris lumbricoides eggs (14.1%), Taeniid spp. eggs (9.2%), Toxocara spp. eggs (3.3%), Trichostrongylus spp. eggs (4.3%), Giardia spp. cysts (8.2%) and non-pathogenic protozoan Entamoeba coli cysts (9.2%). The rate of parasitic contamination in different seasons was found to be 55% in spring, 45.5% in summer, 14.9% in autumn and 12.3% in winter (P < 0.005). The results highlight the potential of unwashed raw vegetables in transmission of intestinal parasites to human, and also emphasize the use of standard washing procedure (proper washing and disinfecting) before consumption of vegetables instead of traditional procedure (quick washing without disinfecting).     

Association of macroscopic laboratory testing and micromechanics modelling for the evaluation of the poroelastic parameters of a hardened cement paste

The results of a macro-scale experimental study performed on a hardened class G cement paste [Ghabezloo et al. (2008) Cem. Con. Res. (38) 1424-1437] are used in association with the micromechanics modelling and homogenization technique for evaluation of the complete set of poroelastic parameters of the material. The experimental study consisted in drained, undrained and unjacketed isotropic compression tests. Analysis of the experimental results revealed that the active porosity of the studied cement paste is smaller than its total porosity. A multi-scale homogenization model, calibrated on the experimental results, is used to extrapolate the poroelastic parameters to cement pastes prepared with different water-to-cement ratio. The notion of cement paste active porosity is discussed and the poroelastic parameters of hardened cement paste for an ideal, perfectly drained condition are evaluated using the homogenization model.     

Order reduction of the dynamic model of a linear weakly periodic system-part I: general methodology

A methodology is presented for the order reduction of the dynamic model of a linear weakly periodic system obtained by linearization about the nonsinusoidal periodic steady state. It consists of two stages. First, the time-invariant part of the original full-order system is approximated by a reduced system by using singular value decomposition techniques. Then the time-varying part of the reduced system is calculated by using a Gauss-Seidel technique. The issues of sparsity, convergence, and accuracy are analyzed. The example used for illustration serves to demonstrate the efficiency of the new method.     

Robust sparse network equivalent for large systems: part I-methodology

This paper deals with the calculation of a sparse network equivalent (SNE) for the analysis of electromagnetic transients in large systems. The main feature of the new approach is the enforcement of sparsity, stability, passivity, and accuracy at specific frequencies of the equivalent. The procedure is based on time-domain fitting with quadratic programming to enforce the constraints. The SNE can be interfaced with transient calculation programs directly in time domain. Results are presented in the companion paper.     

Measurement of harmonics/inter-harmonics of time-varying frequencies

A novel method of extraction and measurement of individual harmonics of a signal with time-varying frequency is presented. The proposed method is based on a nonlinear, adaptive mechanism. Compared with the well-established techniques such as DFT, the proposed method offers (i) higher degree of accuracy, (ii) structural/performance robustness, and (iii) frequency-adaptivity. The structural simplicity of the algorithm renders it suitable for both software and hardware implementations. The limitation of the proposed method as compared with DFT-based methods is its slower transient response. Based on simulation studies, performance of the method is presented and its accuracy and response time are compared with a DFT-based method.