Journal of Garmsar Science and Engineering

Abstract In recent years, the global startup ecosystem has witnessed significant growth, and a promising market for technology-based innovations is emerging in Iran. However, Iranian startups face a unique set of challenges, especially in the field of software development. This study examines the multifaceted challenges that hinder the success of software development projects in Iranian startups. For this purpose, by studying the research literature, 14 major challenges in this field were identified, which were divided into four categories: economic and political challenges, technological, cultural and organizational challenges, and specific challenges for startups. The results of this study showed the significant impact of sanctions and internet restrictions that limit access to essential technologies and global markets. In addition, domestic challenges, such as outdated technology, lack of skilled labor, and bureaucratic obstacles, increase the problems faced by Iranian startups. To overcome these challenges, startups must adopt adaptive strategies and efficient project management methods. Prioritizing efficient resource allocation, effective risk management, and transparent communication are essential to reduce the impact of these challenges. Finally, this study provides valuable guidelines for entrepreneurs, investors, and policymakers to guide innovation and contribute to the country’s economic growth.

Abstract Metals are widely used for various applications due to their good mechanical properties but are always subject to corrosion. Researchers consider corrosion to be an insidious phenomenon because it behaves slowly but steadily and can cause major failures. The economic losses caused by corrosion are always very huge, so the prevention and control of corrosion have always been of great importance. Many methods prevent corrosion, but chemical corrosion inhibitors have always been very popular. They have always been a good choice among other protection methods due to their good efficiency, but the toxicity of many of them causes environmental problems. In recent years, the evaluation and use of green corrosion inhibitors has increased significantly. Among them, the use of plants has received much attention because they contain compounds that have anti-corrosion properties. In this review, the use of plants as green corrosion inhibitors is discussed, focusing on recent developments.

Abstract Geotechnical structures such as pile-sheet walls, wharves, bridge piers, retaining walls, slopes, excavations and underground projects in loose soil of urban areas are exposed to lateral loads and uplift in some cases that may lead to instability. There are several methods for stabilizing geotechnical structures. One of the most common methods for stabilizing geotechnical structures is the anchorage method. In this study, a new plate anchor named “opening plate anchor”, increasing its bearing section area during uplift is introduced. In the present experimental study, the effects of the embedment ratio (embedment depth of anchor to its width) and the width of the anchor (120, 150, 180 mm) in pullout tests are investigated. Particle Image Velocimetry (PIV) is used to study soil deformation around the anchor at maximum pullout load’s instance. According to PIV analysis, two different failure surfaces are observed. The results showed that as the embedment ratio increases, it causes a significant increase in the pullout capacity (P_u), however it does not change the corresponding normalized displacement (d_u/B) noticeably. Increasing the width of anchor, increases anchor’s pullout capacity and corresponding normalized displacement. The PIV results showed that for shallow anchors, the failure surfaces are curved and cross the soil surface, while for deep anchors, the failure surfaces shape a truncated cone in the soil.

Abstract The adhesion of marine microorganisms to the surface of vessels and underwater structures is one of the serious challenges of the marine, oil and gas industries, resulting in significant economic and environmental losses. One of the most important available technologies to combat this phenomenon is antifouling coatings based on self-polishing polymers from the silylacrylate family. Given that the performance of these coatings is mainly dependent on the structure of the silylacrylate resin, in this study, the effect of the structural characteristics of the resin, including type and composition of the monomers and their feeding method (one-shot and dropwise), were investigated. For this purpose, polymers containing 3-5 monomers were synthesized using acrylic acid, methyl methacrylate, butyl acrylate, triisopropylsilyl acrylate and triisopropylsilyl methacrylate and the solution polymerization method. The polymers were characterized using infrared spectroscopy and differential scanning calorimetry and their performance was evaluated by determining the viscosity, water absorption and water contact angle. The results showed that the addition of acrylic acid led to an increase in the glass transition temperature, a decrease in the water contact angle and an increase in the water absorption of the polymers. In addition, the simultaneous use of silyl acrylate and silyl methacrylate functional monomers led to polymerization conversion of 73-78% compared to 61-72% for samples synthesized with one functional monomer. Moreover, the samples synthesized with two functional monomers, and dropwise feeding method, showed to have a more uniform microstructure, higher viscosity and a higher glass transition temperature. These results were attributed to the difference in the reactivity ratio of the monomers and its effect on the polymerization rate and chain microstructure.

Abstract In recent years, the use of louvers as shading devices in office buildings has become a common standard. This usage has turned into a necessity due to climate change and the increasing need for energy conservation. Given that buildings account for a significant share of energy consumption and greenhouse gas emissions, optimizing the design of shading systems such as louvers can help improve energy efficiency and reduce energy costs. The performance of these louvers is highly dependent on their angle, which can be examined from various perspectives, including daylight, thermal loads, visual comfort, natural ventilation, and energy consumption. The aim of this research is to determine the optimal angle of external louvers in office buildings based on solar energy utilization and energy consumption levels. To achieve this goal, a sample building was designed and simulated with louvers installed on three facades: south, east, and west, in 17 different configurations. These simulations were conducted using DesignBuilder software in Tehran. The results of this study confirm the consistency with previous research and indicate that the optimal angle of louvers is climate-dependent. In all examined scenarios, the use of louvers resulted in a reduction of solar gain compared to buildings without louvers. The findings show that for low-rise office buildings in Tehran, the optimal louver angle is +70 degrees on the south facade, -40 degrees on the east facade, and +50 degrees on the west facade. Additionally, energy consumption in these optimal configurations decreased by between 4.9% and 29.28%.