SYNTHESIS AND CONTROL SIZE OF SnS2 NANOPARTICLES ON THE SURFACE MULTI-WALLED CARBON NANOTUBES

ROSTAM MORADIAN,BANDAR ASTINCHAP 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2010 NANO Vol.5 No.3

Multi-walled carbon nanotubes have been decorated by SnS2 nanoparticles with different sizes using a simple chemical method. In this work, first multi-walled carbon nanotubes (MWCNTs) functionalized by using acid mixture, then this system coated by tin disulfide (SnS2) nanoparticles with nanoparticle sizes controlling. The samples have been characterized by X-Ray diffraction and transmission electron microscopy (TEM). We found size and uniformity of the SnS2 nanoparticles influenced by increasing reaction temperature and time. By increasing reaction temperature and time, size of the SnS2 nanoparticles became larger and nonuniform. Also we found that ultrasound waves could be used instead of organic compounds for avoiding agglomeration of the SnS2 nanoparticles on the surface of MWCNTs.

ON ζ-FACTORS AND COMPUTING STRUCTURES IN CYCLIC n-ROOTS

Sabeti, Rostam The Kangwon-Kyungki Mathematical Society 2022 한국수학논문집 Vol.30 No.2

In this paper, we introduce a new concept in number theory called ζ-factors associated with a positive integer n. Applications of ζ-factors are in the arrangement of the defining polynomials in cyclic n-roots algebraic system and are thoroughly investigated. More precisely, ζ-factors arise in the proofs of vanishing theorems in regard to associated prime factors of the system. Exact computations through concrete examples of positive dimensions for n = 16, 18 support the results.

Post Occupancy Evaluation Model for Sustainable Neighborhood Development

Yaman, Rostam,Thadaniti, Suwattana,Dahiya, Bharat,Abdullah, Jamalunlaili,Ahmad, Noraini 한국생태환경건축학회 2017 한국생태환경건축학회 학술발표대회 논문집 Vol.17 No.2

Urban green rating system in the ASEAN region is rather new. Even though certain Green Building Institutes/Green Building Councils (GBIs/GBCs) in the ASEAN region have its Green Township Assessment Criteria (GTAC) been developed and implemented but there is no post-occupancy evaluation being conducted in assessing the effectiveness and sustainability level of the certified township? Thus, embark the research problem whether urban neighborhood assessment criteria and project fulfilled the effectiveness and sustainability concept according to sustainability dimension pillars (SDP). The research aim and objectives is to identify and formulate Post-Occupancy Evaluation Model (POEM) based on SDP towards sustainable neighborhood development for ASEAN region. The study scope focused on Green Building Index (GBI-TAC Malaysia) certified neighborhood project and Green Urban Village Development in Thailand which was occupied for more than one year. The stakeholder-inclusion approached is used in this research in order to gather end-users experiences regarding the proposed POEM for sustainable neighborhood development. The findings suggested there is an adaptation gap of SDP in current GTAC and also significant differences between pre-occupancy and post-occupancy theory and variables, hence lead to further review and refinement towards sustainable neighborhood development in the ASEAN region.

Influence of Spermidine on Haploid Plant Production in Iranian Onion(Allium cepa L.) Populations through in Vitro Culture

Bahram Rostam Forodi,Mohammadreza Hassandokht,Abdolkarim Kashi,Niazali Sepahvand 한국원예학회 2009 Horticulture, Environment, and Biotechnology Vol.50 No.5

The Perspective of Psychological Action Mechanism of Mindfulness Meditation: Mindfulness Meditation Blurs the Transparent Boundary Between the Unconscious and the Conscious Mind

Ahmed Darya Rostam 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.5

Based on the author’s clinical experience, the aim of this paper is to conceptually analyse the theory of psychological functioning and action mechanisms in the way mindfulness meditation works. Meditation is a method of revealing unconsciousness. It works in a similar way to the inhibitory and excitatory mechanisms of neurones. Block pathogenic thoughts and emotions that reach the unconscious to the conscious mind. The long-term implementation of mediation may be more effective than the short-term and interrupted implementation.

Individual Fit Testing of Hearing Protection Devices Based on Microphone in Real Ear

Azam Biaban,Mohsen Aliabadi,Rostam Golmohammadi,Maryam Farhadian 한국산업안전보건공단 산업안전보건연구원 2017 Safety and health at work Vol.8 No.4

Labeled noise reduction (NR) data presented by manufacturers are considered one of the main challenging issues for occupational experts in employing hearing protection devices (HPDs). This study aimed to determine the actual NR data of typical HPDs using the objective fit testing method with a microphone in real ear (MIRE) method. Five available commercially earmuff protectors were investigated in 30 workers exposed to reference noise source according to the standard method, ISO 11904-1. Personal attenuation rating (PAR) of the earmuffs was measured based on the MIRE method using a noise dosimeter (SVANTEK, model SV 102). The results showed that means of PAR of the earmuffs are from 49% to 86% of the nominal NR rating. The PAR values of earmuffs when a typical eyewear was worn differed statistically (p < 0.05). It is revealed that a typical safety eyewear can reduce the mean of the PAR value by approximately 2.5?dB. The results also showed that measurements based on the MIRE method resulted in low variability. The variability in NR values between individuals, within individuals, and within earmuffs was not the statistically significant (p > 0.05). This study could provide local individual fit data. Ergonomic aspects of the earmuffs and different levels of users experience and awareness can be considered the main factors affecting individual fitting compared with the laboratory condition for acquiring the labeled NR data. Based on the obtained fit testing results, the field application of MIRE can be employed for complementary studies in real workstations while workers perform their regular work duties.

Field Study of Effects of Night Shifts on Cognitive Performance, Salivary Melatonin, and Sleep

Reza Kazemi,Majid Motamedzade,Rostam Golmohammadi,Hamidreza Mokarami,Rasoul Hemmatjo,Rashid Heidarimoghadam 한국산업안전보건공단 산업안전보건연구원 2018 Safety and health at work Vol.9 No.2

Background: Night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue. This study set out to measure cognitive performance, melatonin rhythms, and sleep after different consecutive night shifts (7 vs. 4) among control room operators (CORs). Methods: The participants included 60 CORs with a mean age of 30.2 years (standard deviation, 2.0) from a petrochemical complex located in Southern Iran. Cognitive performance was assessed using the n-back task and continuous performance test. To evaluate melatonin, saliva was collected and tested by enzymelinked immunosorbent assay. To assess sleep and sleepiness, the Pittsburgh Sleep Quality Index and Karolinska Sleepiness Scale were used, respectively. Results: Individuals who worked 7 consecutive night shifts had a significantly better cognitive performance and sleep quality than those who worked 4 consecutive night shifts. However, salivary melatonin profile and sleepiness trend were not affected by shift type. Conclusion: The main duty of CORs working night shifts at the studied industry included managing safety-critical processes through complex displays; a responsibility that demands good cognitive performance and alertness. It is suggested that an appropriate number of consecutive night shifts in a rotating shift system should be planned with the ultimate aim of improving CROs performance/alertness and enhancing safety.

Evaluation of Coordination of Emergency Response Team through the Social Network Analysis. Case Study: Oil and Gas Refinery

Mohammadfam, Iraj,Bastani, Susan,Esaghi, Mahbobeh,Golmohamadi, Rostam,Saee, Ali Occupational Safety and Health Research Institute 2015 Safety and health at work Vol.6 No.1

Background: The purpose of this study was to examine the cohesions status of the coordination within response teams in the emergency response team (ERT) in a refinery. Methods: For this study, cohesion indicators of social network analysis (SNA; density, degree centrality, reciprocity, and transitivity) were utilized to examine the coordination of the response teams as a whole network. The ERT of this research, which was a case study, included seven teams consisting of 152 members. The required data were collected through structured interviews and were analyzed using the UCINET 6.0 Social Network Analysis Program. Results: The results reported a relatively low number of triple connections, poor coordination with key members, and a high level of mutual relations in the network with low density, all implying that there were low cohesions of coordination in the ERT. Conclusion: The results showed that SNA provided a quantitative and logical approach for the examination of the coordination status among response teams and it also provided a main opportunity for managers and planners to have a clear understanding of the presented status. The research concluded that fundamental efforts were needed to improve the presented situations.

Field Study of Effects of Night Shifts on Cognitive Performance, Salivary Melatonin, and Sleep

Kazemi, Reza,Motamedzade, Majid,Golmohammadi, Rostam,Mokarami, Hamidreza,Hemmatjo, Rasoul,Heidarimoghadam, Rashid Occupational Safety and Health Research Institute 2018 Safety and health at work Vol.9 No.2

Background: Night shift work is associated with many problems such as sleep deprivation, sleepiness, decreased cognitive performance, increased human errors, and fatigue. This study set out to measure cognitive performance, melatonin rhythms, and sleep after different consecutive night shifts (7 vs. 4) among control room operators (CORs). Methods: The participants included 60 CORs with a mean age of 30.2 years (standard deviation, 2.0) from a petrochemical complex located in Southern Iran. Cognitive performance was assessed using the n-back task and continuous performance test. To evaluate melatonin, saliva was collected and tested by enzyme-linked immunosorbent assay. To assess sleep and sleepiness, the Pittsburgh Sleep Quality Index and Karolinska Sleepiness Scale were used, respectively. Results: Individuals who worked 7 consecutive night shifts had a significantly better cognitive performance and sleep quality than those who worked 4 consecutive night shifts. However, salivary melatonin profile and sleepiness trend were not affected by shift type. Conclusion: The main duty of CORs working night shifts at the studied industry included managing safety-critical processes through complex displays; a responsibility that demands good cognitive performance and alertness. It is suggested that an appropriate number of consecutive night shifts in a rotating shift system should be planned with the ultimate aim of improving CROs performance/alertness and enhancing safety.

Individual Fit Testing of Hearing Protection Devices Based on Microphone in Real Ear

Biabani, Azam,Aliabadi, Mohsen,Golmohammadi, Rostam,Farhadian, Maryam Occupational Safety and Health Research Institute 2017 Safety and health at work Vol.8 No.4

Background: Labeled noise reduction (NR) data presented by manufacturers are considered one of the main challenging issues for occupational experts in employing hearing protection devices (HPDs). This study aimed to determine the actual NR data of typical HPDs using the objective fit testing method with a microphone in real ear (MIRE) method. Methods: Five available commercially earmuff protectors were investigated in 30 workers exposed to reference noise source according to the standard method, ISO 11904-1. Personal attenuation rating (PAR) of the earmuffs was measured based on the MIRE method using a noise dosimeter (SVANTEK, model SV102). Results: The results showed that means of PAR of the earmuffs are from 49% to 86% of the nominal NR rating. The PAR values of earmuffs when a typical eyewear was worn differed statistically (p < 0.05). It is revealed that a typical safety eyewear can reduce the mean of the PAR value by approximately 2.5 dB. The results also showed that measurements based on the MIRE method resulted in low variability. The variability in NR values between individuals, within individuals, and within earmuffs was not the statistically significant (p > 0.05). Conclusion: This study could provide local individual fit data. Ergonomic aspects of the earmuffs and different levels of users experience and awareness can be considered the main factors affecting individual fitting compared with the laboratory condition for acquiring the labeled NR data. Based on the obtained fit testing results, the field application of MIRE can be employed for complementary studies in real workstations while workers perform their regular work duties.