Pathogenic microorganisms are causative agents for different types of serious and even lethal infectious diseases. Despite advancements in medication, bacterial and fungal infections continue to be a growing problem in health care. As more and more bacteria become resistant to antibiotics used in therapy and an increasing number of invasive fungal species become resistant to current antifungal medications, there is considerable interest in the development of new compounds with antimicrobial activity. The compounds containing a heterocyclic ring play an important role among organic compounds with biological activity used as drugs in human and veterinary medicine or as insecticides and pesticides in agriculture. Thiadiazoles belong to the classes of nitrogen–sulfur heterocycles with extensive application as structural units of biologically active molecules and as useful intermediates in medicinal chemistry. The potency of the thiadiazole nucleus is demonstrated by the drugs currently used. 1,3,4-Thiadiazoles and some of their derivatives are extensively studied because of their broad spectrum of pharmacological activities. The aim of this review was to highlight the main antimicrobial properties exhibited by derivatives possessing 2-amino-1,3,4-thiadiazole moiety. Many of the reported 2-amino-1,3,4-thiadiazole derivatives can be considered as lead compounds for drug synthesis, and several of them have demonstrated higher antimicrobial activity in comparison to standard drugs. Furthermore, taking into account the reactivity of the amine group in the derivatization process, 2-amino-1,3,4-thiadiazole moiety may be a good scaffold for future pharmacologically active 1,3,4-thiadiazole derivatives.

The study introduces a cleaning method of waste waters with nickel and cobalt ions content, by the precipitation of these ions as oxalates. The aim of the study is to establish the optimum conditions for a high degree of a metal recovery like nickel oxalate or cobalt oxalate, due to the low value of their products of solubility. The parameters studied were: pH, excess of reactant reagents, concentration of ions and temperature. The crystalline form of the obtained products corresponds to: NiC2O4�2H2O and CoC2O4�2H2O and extraction degree of metals was around 99%.

The Aim of the Research: Anethum graveolens (dill) is a common herb used in traditional Romanian cuisine, as well as in phytotherapy. Dill seeds have been reported to be rich in antioxidants. As interest in food additives of natural origin has increased in recent years, the purpose of this paper was to study the composition and antioxidant potential of Romanian dill seeds. Methodology: In this study, the total phenolics contents, the phenolic profile, and the antioxidant properties of the methanolic and hydromethanolic extracts of Romanian dill seeds were investigated. Folin-Ciocalteu assay, DPPH spectrophotometrically method and reverse-phase high-performance liquid chromatography RP-HPLC, respectively were applied. Results: The highest content of total phenolics was found in acidified methanol samples (46.5 - 46.8 mg GAE/g dry seeds). RP-HPLC analysis highlights important content of quercetin, kaempferol, caffeic acid, sinapic acid, gallic acid, vanillic acid, (±) - catechin and umbelliferone. Antioxidant activity, measured via DPPH free radical scavenging ability, showed very high values (93.5 - 95.6% for the crude extracts and 67.5 - 93.2% for extracts at a concentration of 0.25 mg/mL). Methanolic extract exhibited the best IC50 value (88.7 ± 0.01 μg/mL). Conclusion: All experiments proved the antioxidant activity of dill seed extracts.

The performed studies regarding the cylindrical gears with curved teeth or in V showed that a uniform distribution of the load on the flanks is hard to realise, generally being necessary later finishing processing or modifying the gear by camber or flanking, which suppose supplementary expenses. On the basis of these mentions and taking into account the advantages of curved bevel gear, the purpose of this paper is to present an original study regarding the mathematical model for generation of a curved cylindrical gear with high performances. The cycloidal gear was chosen after a technical and an economical study regarding on the possibility of practical implementation with the lowest production costs using a special device, adapted on a Phauter processing machine of cylindrical gear. This was the main reason for choosing a cycloidal profile from several types of curved teeth (cycloidal arc, circle arc, Archimede’s spiral, involute arc). So, the main aim of the paper is to determine the equations of the flanks of cylindrical wheel with curved teeth in oblong cycloidal arc, in order to establish if the technical generation is possible. The curved cylindrical teeth with cycloidal flanks is generated by rolling with straight mobile line and continuous division by using a milling cutter with 1, 2, 3, 6 groups of knifes equidistantly placed, fixed on an adaptable device on a Phauter processing machine. The two curves which define the flank are simultaneously generated by correlated motions, and the flanks of the wheel part result as a roll of successive positions of generating hook materialized by the cutting edge of the tool. The shape of the contact curve between the conjugated surfaces of generating element and the wheel part can be obtained if you are taking into account the kinematic condition. Using this condition you can determine the relationship between the kinematic, geometric and technological parameters. The line of the flanks is studied in the reference plane and in parallel planes with this, and the profile of the flanks is determined in perpendicular planes on the work piece axis. Based on the parametric equations it was made the simulation program in MATLAB that indicates that this gears can be obtained, and constitutes the first step in practical manufacturing of this kind of gears. By analyzing the obtained shape they result useful conclusions for the manufacturing of the involute-tooth gear with curved oblong cycloidal arc. On the other hand, using Solid Edge it was made the spatial modeling of the cylindrical gear with curved cycloidal teeth that allows next FEA studies regarding on the contact and bending stress.

Natural clay from the Felix geothermal area was used to assess the possible removal of heavy metals from wastewaters. Several experimental conditions, including pH, contact time and temperature, depending on the initial concentration were studied. The design of experiments method was applied in order to get the highest percentage of adsorbed copper. The factorial experiments were performed according to the matrix program developed by Design Expert. The obtained mathematical model assessed the optimal values of the factors that influence the adsorption of copper, taking into account maximum productivity, as well as economic criteria. The estimated values were in accordance with the experimental research.