Showing 4 results for Dastgheib
Fatemeh Gholami, Mahmoud Shavandi, Seyed Mohammad Mehdi Dastgheib, Mohammad Ali Amoozegar,
Volume 11, Issue 4 (fall 2020)
Abstract
Application of oxygen releasing compounds (ORCs) is considered as a novel method in petroleum hydrocarbon remediation from groundwater. ORCs destroy chemically the contaminant by exposure to water which results in hydroxyl radical generation or biologically remove the pollution by biostimulation of the groundwater native microorganisms aerobically. In the present study, calcium peroxide (CaO2) nanoparticles were applied to supply the required oxygen for growth and activity of the native microorganisms to consume naphthalene (20 ppm) as a carbon source. Additionally, the effect of CaO2 content, temperature and pH on the performance of nanoparticles were investigated in the naphthalene removal. The results indicated that the microbial population was sharply increased in the presence of 400 mg/L of nanoparticles and at 30oC and the contaminant was completely removed after 20 days at neutral pH. Furthermore, naphthalene was 100% remediated from groundwater at pH 3, 7.4 and 12 after 2, 20 and 30 days, respectively. This proved the acceleration of chemical oxidation under the acidic condition. At 15 and 30 ± 0.5 oC the contaminant was removed from the media within 15 and 20 days respectively. Meanwhile, only 75% of contaminant was remediated from groundwater within 30 days at 4 ±0.5oC which was due to the reduction in the biological activity and the chemical reaction rate.
Zeinab Vanak, Sedigheh Asad, Seyed Mohammad Mehdi Dastgheib,
Volume 14, Issue 1 (FALL 2023)
Abstract
Phenols are organic and highly toxic compounds commonly found in the effluents of various industries due to their wide range of applications. The inhibitory effect of phenol at high concentrations, as well as the high salinity of industrial effluents, poses a serious challenge for treatment by microorganisms. One of the most common approaches to overcome this problem is the immobilization of phenol-degrading microorganisms. The aim of this study was to study the immobilization effect on the phenol removal efficiency of native Janibacter halotolerant bacterium. For this purpose, mica was used as a carrier for bacterial immobilization and the protein concentration assay was applied to determine the immobilization efficiency. The phenol removal by free and immobilized cells was studied as well as the effect of different parameters on phenol removal efficiency. The immobilization efficacy on mica was %68.75, based on protein concentration measurements. The removal time of 100 mg/L phenol by suspended cells was 88 h, while the immobilized cells degraded it in 40 h. Immobilized cells, unlike free cells, were able to remove phenol at lowered temperatures up to 16℃
, salt concentrations greater than 7/5%, and pH levels below 7/5 and above 8/5. Similar results regarding the superior performance of immobilized cells have been obtained in other studies. As a result, the immobilization process considerably improves the efficiency of phenol removal and makes the cells resistant to harsh environmental conditions by protecting the cells from the toxic effects of phenol.
Volume 14, Issue 2 (summer 2024)
Abstract
Objective: The main objective of this article is to answer this question in the first step; What are the most important principles of the constitution related to the economic field of the country, and what are the religious sources of these principles? In the next step, the problems and obstacles of the proper and favorable effect of economic laws in the economic advancement of the country should be examined and verified with the aim of providing path-breaking suggestions.
Methodology: This research is descriptive-analytical and its data is collected from the library and electronic sources.
Research findings: The result of the research shows that almost all the important economic principles of the constitution are based on religious sources, especially the Holy Quran. Despite their religious validity and relative comprehensiveness, these laws have faced obstacles in some cases to be effective in the economic field: the lack of transparency in terms and definitions such as "ownership" is one of the obstacles to the maximum effectiveness of the laws. In the absence of effective and transparent laws, many activities of the quasi-governmental or semi-governmental sector cannot be directly monitored and their negative effects are evident in the country's economy. The breadth and breadth of concepts and terms in some principles have led to different interpretations and interpretations, which did not achieve the desired result of the legislator (for example, principle 44 and the discussion of privatization). The contradiction and inconsistency of some laws with each other and even the different sentences of the same principle have weakened the expected effect (principle 28 of the Constitution, which weakens the second sentence of the first sentence). On the other hand, in the absence of transparency and discipline, the country's economic sphere has taken on a law-abiding nature and has moved away from flexibility and rule of law.
Research innovation: With regard to the possibility of making it operational in the field of economic law, the interaction between the legislator and the economic activist (company or person) will become more prominent and in an interactive atmosphere, the correction and revision of laws will be put on the agenda with the aim of achieving discipline and transparency in the economic field. The field of economy at the macro level of the country can provide the necessary platforms for the dynamics of economic rights.
Volume 21, Issue 155 (12-2024)
Abstract
The juice industry is seeking cost-effective Pulsed Electric Fields (PEF) reactor systems to treat bulk fluid. The paper discusses the development of a helix-shaped glass chamber (HSGC) for PEF treatment in the juice industry. PEF treatment is a non-thermal technology used for the preservation and processing of fruit juices. The HSGC design aims to improve the efficiency and effectiveness of PEF treatment by enhancing the distribution of electric fields within the chamber. The PEF treatment is believed to be biochemical and physical parameters. The traditional designs don't have good attributes for uniformity of PEF treatment and long fluid residence time. The developed HSGC was successfully applied on mango juice samples, and variation of chemical parameters including viscosity and conductivity, including microbial inactivation of microorganisms (Escherichia coli), was explored. The results are compared with the new values of the juice condition. The simulation results indicate that the juice fluid remains at a normal temperature range of 20-25°C. The results were encouraging and discussed, suggesting that HSGC is a viable option for processing sour mango juice with a significant amount of microbial inactivation without adversely affecting the physical and biochemical parameters. In addition, it is effective for long-term preservation of fruit juices and liquids. The residence time in the treatment chamber, the intensity, and uniformity of PEF treatment affect the variation in chemical. The results demonstrate the feasibility and advantages of using the helix-shaped chamber for PEF treatment, offering potential benefits for juice quality and shelf life. Overall, the paper provides valuable insights into the development of innovative technologies for the juice industry.
