One of the important issues in the production of concrete is environmental variability that affects the concrete and elements constructed from this material. Due to the importance of different characteristics of concrete in short- and long-term conditions, this article aims to investigate the influence of initial temperature conditions of self-compacting concrete on its long-term characteristics and determine the initial optimal temperature of concrete. For these purposes, several experiments under three temperature conditions of 5, 20, and 40 degree-of-Celsius were conducted to evaluate the rheology and mechanical properties of fresh concrete in the range of 7 and 28 days. In these experiments, alternative mineral admixtures of cement such as micro-silica, fly ash, and zeolite were used to build the concrete specimens. Results demonstrate that the mechanical properties of the specimens increase with increasing initial temperature in the short term, while such properties significantly decrease in the long term compared to the specimens constructed under lower initial temperature. Moreover, the fluidity of self-compacting concrete increases with increasing initial temperature.

The use of nano fillers is a good strategy to improve the properties of biopolymer-based packaging films. The present study prepared zein-based nano composite film containing montmorillonite using the solvent casting method. Mechanical, barrier, and thermal properties of the film were investigated. The x-ray diffraction patterns indicated that the composite film has an exfoliated structure. The results showed that the montmorillonite significantly improved the mechanical, barrier, and thermal properties of the zein film. The highest elongation (9.65%) and tensile strength (22.62 MPa) were obtained for the zein nano coposites containing 0 and 10% montmorillonite, respectively. Increasing the montmorillonite content from 0% to 5% decreased the water vapor permeability of the zein film from 1.73 to 1.23 (28%). This parameter significantly increased (1.93) in film containing 10% montmorillonite. The thermal degradation temperature of zein film increased (from 353 to 373 °C) by increasing the montmorillonite content from 0% to 10%. The results revealed that a small amount of montmorillonite can improve the mechanical and barrier properties of zein film, although uniform dispersion of montmorillonite in the zein network is essential to improving the properties of the film.

One of the factors that can be the link between our intentions and actions and their external consequences is human agency, which indicates the conscious design and intentional execution of actions by the individual in order to influence future events.Objective and Method: This research with a developmental approach of psychometric method and method 1, examines the psychometric indices of the Human Factor Characteristics Scale using the classical theory of test score measurement and the graduated question-answer theory. The purpose of this study, which included high school students in Tehran, was selected by cluster sampling of 500 people as a sample size and statistical analysis was performed on 481 data. To collect the data, the ion Human Agent Characteristics Scale (2011) was used and the research questions were evaluated using IRTPRO and SPSS software.Results:The assumption of local independence based on Pearson x2 index was established by applying Simjima's calibrated question-answer theory and the assumption of being one-dimensional based on the analysis of multidimensional question-answer theory. Diagnosis parameters with question-answer approach and classical approach Test score Both item 25 approach had the lowest and item 2 had the highest diagnosis parameter. The answer thresholds for all the questions were so far apart that no option was covered by the other option, and the options were independently selected by individuals at intervals of theta. The total scale was calculated with Cronbach's alpha of 0.945, intentionality of 0.894, foresight of 0.780, self-reactivity of 0.871 and rethinking of 0.762. Also, the role of each item in internal consistency was investigated by the loop method, which all questions had a favorable role in internal consistency of this scale. The value of the validity coefficient obtained from the question-answer theory was obtained by marginal method for intentionality 0.92, forethought 0.85, self-reaction 0.91, rethinking 0.83..

Due to the importance of the packaging industry and the increasing development of this industry, the importance of packaging and quality of all types of food products is important. Packaging should protectes the product from production to consumption against a variety of physical, chemical and biological factors to deliver a high quality and safe product to the customer. On the other hand, due to the importance of the environment and the emphasis on the formation and implementation of projects and processes with the aim of cleaning the environment, the packaging industry is also going towards using bio-based materials and less contaminating in the environment. Paper is one of the main packaging materials that can protect the product from damage without sacrificing its quality while being flexible, degradable, recyclable, and printable. Types of paper are used for this purpose. Recently, a new generation of paper with the name of the stone paper has entered the market that one of its uses is in packaging. In this paper, the mechanical and barrier properties of this type of paper are evaluated and compared with gloss paper, which is a high-quality type of cellulose fiber paper.

Carboxylated nitrile butadiene rubber (XNBR)-based gloves are commonly used to protect users’ hands from the aggressive environment in various industrial applications. Permeation resistance and mechanical properties of gloves should be simultaneously considered to accomplish adequate protection. Accordingly, in this study, XNBR was reinforced with different amounts of nanoclay and the resulting dispersion was examined using X-ray diffraction and transmission electron microscope. The results showed that, nanoclay has been appropriately dispersed in XNBR lattice and therefore, considerable enhancements in mechanical properties, including tensile strength and modulus were gained. The permeation resistance of the synthesized nanocomposites was studied by two solvents, including perchlorethylene and aniline with low and high affinity to XNBR, respectively. Using permeation test cell, parameters of breakthrough time (BT) and steady-state permeation rate (SSPR) were determined. The BT and SSPR of aniline in nanocomposites with 3 phr nanoclay in comparison with neat polymer were increased 89% and decreased by 11%, respectively. Degradation resistance test of nanocomposite demonstrated acceptable integrity of its barrier properties after repeated exposure to selected chemicals. Analysis of mechanical properties and permeation indices of synthesized nanocomposites illustrated that the application of these materials for manufacturing protective gloves seems promising.

Starch is found in abundance in nature and it is one of the raw materials used for food packaging because of the low price, biodegradability, good mechanical and barrier properties. The recycling ability of coating materials was significantly increased by using edible films and coating in comparison to traditional packaging and it could be an alternative for synthetic films. In this research, the effect of eucalyptus extract (Aqueous Extract) was investigated on tapioca starch films. Tapioca starch films were prepared by casting method with addition of eucalyptus extract and a mixture of sorbitol/glycerol (weight ratio of 3 to 1) as plasticizers. Eucalyptus extract incorporated to the tapioca starch films were dried at different concentrations (0, 15, 25, and 35 of total solid) under controlled conditions. Physicochemical properties such as water absorption capacity (WAC), water vapor permeability (WVP) and mechanical properties of the films were evaluated. Results showed that by increasing the concentration of eucalyptus extract, tensile strength was increased from 20.60 to 15.68 (MPa), also elongation was increased from 19.31 to 23.57 (%) at break and Young’s modulus was decreased from 800.31 to 500.32 (MPa). Also incorporation of eucalyptus extract in the structure of biopolymer increased permeability of water vapor of starch films. Tapioca starch films incorporated with eucalyptus extract exhibited excellent antimicrobial activity againstE. Coli. In summary, eucalyptus extract improves functional properties of tapioca starch films and this types of films can be used in food packaging.