Molecular dynamics simulations of the rotational and translational diffusion of a Janus rod-shaped nanoparticle

The diffusion of a Janus rod-shaped nanoparticle in a dense Lennard-Jones fluid is studied using molecular dynamics (MD) simulations. The Janus particle is modeled as a rigid cylinder whose atoms on each half-side have different interaction energies with fluid molecules, thus comprising wetting and nonwetting surfaces. We found that both rotational and translational diffusion coefficients are larger for Janus particles with higher wettability contrast, and these values are bound between the two limiting cases of uniformly wetting and nonwetting particles. It was also shown that values of the diffusion coefficients for displacements parallel and perpendicular to the major axis of a uniformly wetting particle agree well with analytical predictions despite a finite slip at the particle surface present in MD simulations. It was further demonstrated that diffusion of Janus particles is markedly different from that of uniform particles; namely, Janus particles preferentially rotate and orient their nonwetting sides along the displacement vector to reduce drag. This correlation between translation and rotation is consistent with the previous results on diffusive dynamics of a spherical Janus particle with two hemispheres of different wettability.Comment: 27 pages, 9 figure

Modelling the Role of University-Industry Collaboration in the Iranian National System of Innovation: Generating Transition Policy Scenarios

In a knowledge-based economy the collaboration between university, industry and government is vital for growth and innovation (Etzkowitz, 2008). A conceptual model of the relevant macro and micro environment was developed using the theoretical constructs from the literature on systems of innovation theories including, National Systems of Innovation, Porter’s ‘Cluster’ or ‘Diamond’ model, and the ‘Triple-Helix Model’ of university–industry-government interactions. The role of culture and trust in different systems of innovation theories was examined, and the role these elements play in UIC activities was found to be particularly important, though vague on the processes. A generic model of university-industry-government interrelations was developed to aid a systemic understanding of the mechanisms (primary barriers and drivers) for productive collaboration. This systems model was used in the formation of policy instruments designed to improve university-industry collaboration (UIC), and thereby the means of regional economic development. These policy experiments are applied to the case of Iran. However, since the future of Iran in this context is highly uncertain due to cultural, political and economic factors there are few assumptions which can be relied upon as a basis for traditional innovation management practice. Instead, it is intended to use the systems model in a series of scenario-based analyses of the effectiveness of policy instruments on the UIC associated with two Iranian cluster industries. A questionnaire survey and a series of semi-structured stakeholder interview methodology were used to build a basis for these scenario techniques. The method of systems modelling to generate policy change scenarios for UIC is a novel feature of this research. Analysis of the causal relationships of UIC activities in Iran found many were biased to create an established behaviour pattern (culture) which is overwhelmingly negative. This negative behaviour is manifest as a significant lack of trust at all interfaces between the primary actors in the system. According to the results of this research, trust is influenced by many factors including government activities, institutional structure, institutional culture, and also national culture of the country. The systems model is a complex interaction of reinforcing loops that emphasizes the scale of challenge policy-makers face in creating effective innovation systems, and may explain why few developing countries have been successful in achieving economic transition. This research shows how a policy development framework was formed using the UIC systems model to understand the structural problems facing Iran. A set of evolved states (exploratory and future-backward scenarios) served to illustrate the effect of these policy choices, and therefore to inform an improvement agenda for UIC activities in Iran

Assessing the child friendly city indicators in Mashhad metropolis

Objective: Cities and urban spaces can be either positive or negative locations for children. Neighborhoods must ideally be social places for children so that they can easily state the principles of communities and cultures and exchange them with children. This research aimed to study the status quo and the effectiveness of each of CFC indicators in order to evaluate the life satisfaction in Mashhad, Iran. In this regard, we reviewed the CFC literature. Methods: This is an applied, descriptive survey researh. CFC's theoretical principles and literature were reviewed using the documentary studies. Then, the indicators were extracted and localized using the dimensions stated in the last UNICEF Report (2007) and valid sources in this regard. In the first stage, the status was reviewed by a field visit. Data were collected using a researcher-made questionnaire in order to assess the status quo and the effectiveness of indicators from the perspective of parents with 6-12 year-old children and children in some child-based questions. The statistical population consisted of 13 Municipal Districts of Mashhad, Iran. Districts 1, 6, and 8 were selected as the sample using clustering based on the municipal income in 2014. District 1 represents rich class; District 8 shows semi-rich class; and District 6 represents poor class. Data were analyzed by SPSS. To assess the hypothesis, firstly Kolmogorov-Smirnov Test was used in order to test the normality of the data and then T. test, Tukey test and ANOVA were employed to review the current situation and the impact indicators as well as the gap analysis. Results:The results indicated that the effects of the following indicators were not significant in the formation of CFC in Mashhad: Participation in decision-making, health, education, and culture. According to the UNICEF standards, the results of the status quo also showed that all indicators were ranked medium or medium-to-low regardless of quantitative scale using field observations. The measures were among those for developing and developed countries. In quantitative assessment, all indicators were greater than the statistical standard (number 3) except for Playground and Green Spaces Conclusion: Promoting welfare and healthy city indicators in CFCs requires the participation of all agencies. Municipality as the coordinator between authorities and training and educational bodies can play a key role in this regard. Urban management has come to the conclusion that children are prioritized and municipality is an important part of this element. Without participation, the ultimate goal, which is the healthy society, is not fulfilled

Diffusion of a Janus nanoparticle in an explicit solvent: A molecular dynamics simulation study

Molecular dynamics simulations are carried out to study the translational and rotational diffusion of a single Janus particle immersed in a dense Lennard-Jones fluid. We consider a spherical particle with two hemispheres of different wettability. The analysis of the particle dynamics is based on the time-dependent orientation tensor, particle displacement, as well as the translational and angular velocity autocorrelation functions. It was found that both translational and rotational diffusion coefficients increase with decreasing surface energy at the nonwetting hemisphere, provided that the wettability of the other hemisphere remains unchanged. We also observed that in contrast to homogeneous particles, the nonwetting hemisphere of the Janus particle tends to rotate in the direction of the displacement vector during the rotational relaxation time.Comment: Web reference added for animations:http://www.wright.edu/~nikolai.priezjev/janus/janus.htm

Evaluation of quality of urban life with emphasis on health; A case study in Mashhad city

Background: The quality of life of the citizens is one of the most important issues studied in different countries and used in the planning and monitoring of public policies. The present study measured and evaluated the indicators of quality of urban life among citizens of Mashhad city. Methods: This analytical study was conducted on 375 citizens of various regions in Mashhad city. The random sampling method using population distribution and short-form questionnaires for data collection were applied. The validity of the questionnaires was verified by experts and the points given each question based on a 5-point Likert scale, and the Cronbach αcoefficient was used to measure the reliability of the questionnaire; the questionnaire rated 0.853%. To analyze the variables under study, SPSS and other statistical methods such as average answers and t test for independent variables were used. Results: Findings of this research showed that the average health-sanitation dimension and environmental quality dimension are lower than 50% in Mashhad city. Sanitation and health, with a standard deviation of 5.838, are situated below the median level. The most common weakness is related to the dietary intake of protein. Environmental quality with a standard deviation of 5.857 is lower than the median level which is related to garbage separation and landfill sites. This result indicates that the quality of health and the environment in Mashhad is undesirable. Conclusion: Citizens’ satisfaction with quality of life index is lower than average in Mashhad city. Plans for improving the quality of life and developing services are highly necessary for increasing the quality of life. Keywords: Sanitation, Personal satisfaction, Quality of life, Urban heal

Effects of Real Surface Roughness on Fluid Flow in Nanochannels

ABSTRACT In the present study, a computer program based on a molecular dynamics scheme has been developed for simulating fluid flow in nano-and micro-channels with roughness. According to the previous studies of nanochannels flows, surface roughness has a great effect on the rheology of the flow. Therefore a more realistic surface roughness has been developed and its influence on the fluid flow has been investigated using Molecular Dynamics (MD) Simulation

Modeling the Impact of Urban Management on the Livability of Mashhad (Case Study: Districts 6 and 9)

Introduction: Cities are the focal point of many concerns that affect their sustainability. Urban livability is associated with quality of life, sustainability, quality of place and healthy communities.The livability of cities is highly influenced by the actions of urban management as the main custodian of city affairs, and the balance between these two sectors promotes urban livability.Data and Method: The present study has a practical purpose and descriptive-analytical nature and has been done by quantitative method and by distributing a questionnaire among 384 citizens of the 6th and 9th districts of Mashhad metropoli. The collected data were evaluated and analyzed using SPSS software and t-test as well as structural equation modeling (SEM) with AMOS software.Results: Findings show that in the current situation, the livability dimension in Region 9 is at a desirable level with an average of 3.97.  The average dimensions of urban management in region 9, with an average of 3.14 shows a higher than average situation.  The average dimension of livability in region 6, equal to 3.034, the situation is above average and the dimensions of urban management equal to 2.40, which is undesirable. The results showed that in terms of how urban management measures affect livability, in region 6 the index of livability services (access, environment, housing, health) has a high impact and has a direct relationship in region 9 investment index with all five  Resilience index (access, environment, housing, health care, security) has a strong impact and a direct relationship.Conclusion: There is a need to promote the current situation of both urban management indexes and livability measures in Mashhad. Results also show that urban management can affect many of livability measures and therefore requires a careful considerations

Bioterrorism and its impact on the security of citizens

Objective:Recent advances in the field of biological sciences, on the one hand, and misuse of the results of scientific research by terrorist groups, on the other hand, have caused microbial agents to become fatal weapons that simultaneously threaten national security and public health of the societies. Low costs, easy access and provision, immediate effect, rapid expansion and their extremely high effect on the spread of sense of insecurity has made these types of terrorist acts attractive to some terrorist groups. Methods: This research uses descriptive - analytical method and refers to valid sources to study the biological agents that may be used by terrorists. It also tries to specify the most important methods of transmission of these agents and understand the effects of bioterrorist attacks on the security and health of citizens. Results: The results of the research indicate that bioterrorism is more dangerous than other types of terrorism for threatening the life of citizens and ordinary people due to the attractions of biological materials for terrorists. Some of these characteristics and attractions include difficulty of identifying the biological agents, sufficiency of a small amount of biological agents for a bioterrorist attack, easier spread of biological agents, difficulty of defense against biological agents, possibility of making, production, warehousing and storage of biological weapons in a small and simple place, and having incubation period. Conclusion: Due to these characteristics, biological agents have become attractive temptations for terrorists. They can use biological agents for a terrorist attack on urban infrastructure in sectors of water, food, public services, etc. and threaten the lives of the citizens. In spite of the various protective measures of the governments, most people and citizens are vulnerable to this kind of terrorism. Therefore, it is necessary to carefully examine the extent and the special ways of vulnerability of people and infrastructure to these types of attacks and to formulate security attachments for prevention of such attacks. This is especially true in respect of Iran that is more vulnerable to such attacks

Cost-of-Illness Analysis of Type 2 Diabetes Mellitus in Iran

Diabetes is a worldwide high prevalence chronic progressive disease that poses a significant challenge to healthcare systems. The aim of this study is to provide a detailed economic burden of diagnosed type 2 diabetes mellitus (T2DM) and its complications in Iran in 2009 year.This is a prevalence-based cost-of-illness study focusing on quantifying direct health care costs by bottom-up approach. Data on inpatient hospital services, outpatient clinic visits, physician services, drugs, laboratory test, education and non-medical cost were collected from two national registries. The human capital approach was used to calculate indirect costs separately in male and female and also among different age groups.The total national cost of diagnosed T2DM in 2009 is estimated at 3.78 billion USA dollars (USD) including 2.04±0.28 billion direct (medical and non-medical) costs and indirect costs of 1.73 million. Average direct and indirect cost per capita was 842.6±102 and 864.8 USD respectively. Complications (48.9%) and drugs (23.8%) were main components of direct cost. The largest components of medical expenditures attributed to diabetes's complications are cardiovascular disease (42.3% of total Complications cost), nephropathy (23%) and ophthalmic complications (14%). Indirect costs include temporarily disability (335.7 million), permanent disability (452.4 million) and reduced productivity due to premature mortality (950.3 million).T2DM is a costly disease in the Iran healthcare system and consume more than 8.69% of total health expenditure. In addition to these quantified costs, T2DM imposes high intangible costs on society in terms of reduced quality of life. Identification of effective new strategies for the control of diabetes and its complications is a public health priority

Diffusion of a Janus Nanoparticle in an Explicit Solvent: A Molecular Dynamics Simulation Study

Molecular dynamics simulations are carried out to study the translational and rotational diffusion of a single Janus particle immersed in a dense Lennard-Jones fluid. We consider a spherical particle with two hemispheres of different wettabilities. The analysis of the particle dynamics is based on the time-dependent orientation tensor, particle displacement, as well as the translational and angular velocity autocorrelation functions. It was found that both translational and rotational diffusion coefficients increase with decreasing surface energy at the nonwetting hemisphere, provided that the wettability of the other hemisphere remains unchanged. We also observed that in contrast to homogeneous particles, the nonwetting hemisphere of the Janus particle tends to rotate in the direction of the displacement vector during the rotational relaxation time