An investigation in crashworthiness evaluation of aircraft seat cushions at extreme ranges of temperature

Hamid Khademhosseini Beheshti,Hamid Lankarani 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.5

This paper obtains a Mathematical Dynamic Model (MADYMO) for occupant lumbar load evaluation under CFR Part 23 and 25 at extreme ranges of temperature. The validation of results is performed by full scale sled test results. Aircraft industries are using viscoelastic polyurethane foams as seat cushion. Visco-elastic foams bring not only more comfort to the passengers in long term sitting but it also maintains more safety during unpredicted crashes and hard landings. Aircraft seat cushions are exposed to varying temperature ranges during their life time. This fact has motivated aircraft industries to evaluate the seat cushion dynamic behavior at extreme ranges of temperatures in addition to what is mentioned in Federal Aviation Administration (FAA) Regulations at room temperature. This research provides a methodology based on simulation and modeling to eliminate, or at least, minimize the number of full scale dynamic sled tests defined by regulations for aircraft seats at extreme ranges of temperature.

Generation of Retinal Pigmented Epithelium-Like Cells from Pigmented Spheres Differentiated from Bone Marrow Stromal Cell-Derived Neurospheres

Hamid Aboutaleb Kadkhodaeian,Taki Tiraihi,Hamid Ahmadieh,Hossein Ziaei,Narsis Daftarian,Taher Taheri 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.3

BACKGROUND: Retinal degeneration causes blindness, and cell replacement is a potential therapy. The purpose of this study is to formation of pigmented neurospheres in a simple medium, low-cost, high-performance manner over a short period of time while expressing markers of RPE cells and the activation of specific genes of the pigment cells. Also, these neurospheres have the ability to produce a monolayer of retinal pigment epithelium-like cells (RPELC) with the ability of photoreceptor outer segment phagocytosis. METHODS: BMSC were isolated from pigmented hooded male rats and were immunoreactive to BMSC markers, then converted into neurospheres, differentiated into pigmented spheres (PS), and characterized using Retinal pigment epithelium-specific 65 kDa protein (RPE65), Retinaldehyde-binding protein 1 (CRALBP) and orthodenticle homeobox 2 (OTX2) markers by immunocytochemistry, RT-PCR and RT-qPCR. The PS were harvested into RPELC. The functionality of RPELC was evaluated by phagocytosis of fluorescein-labeled photoreceptor outer segment. RESULTS: The BMSC immunophenotype was confirmed by immunostained for fibronectin, CD90, CD166 and CD44. These cells differentiated into osteogenic and lipogenic cells. The generated neurospheres were immunoreactive to nestin and stemness genes. The PS after 7–14 days were positive for RPE65 (92.76–100%), CRALBP (95.21–100%) and OTX2 (94.88–100%), and after 30 days RT-PCR, qPCR revealed increasing in gene expression. The PS formed a single layer of RPELC after cultivation and phagocyte photoreceptor outer segments. CONCLUSION: Bone marrow stromal stem cells can differentiate into functional retinal pigmented epithelium cells in a simple, low-cost, high-performancemanner over a short period of time. These cells due to expressing theRPELCgenes andmarkers can be used in cell replacement therapy for degenerative diseases including age-relatedmacular degeneration as well as retinitis pigmentosa.

The Impact of Supply Chain Management on Organizational Performance and Customer Satisfaction

Hamid Babaei Meybodi,Seyed Hamid Emadi,Tina Roostapisheh,Haniyeh Ghiyasvand Mohammadkha 대한산업공학회 2018 Industrial Engineeering & Management Systems Vol.17 No.3

The present study has been conducted with the purpose of investigating the impact of supply chain management (SCM) on organizational performance and customer satisfaction in two factories in Shiraz Industrial Estate. Therefore, according to the research subject, the variables of supply chain management, organizational performance and also customer satisfaction have been defined. In terms of objective, this is an applied study and in terms of nature and method, this is a descriptive-correlational study. The statistical population consists of 100 people and the sample consists of 80 people. The reliability and validity of research have firstly been examined and then the results were analyzed using SPSS and LISREL. The obtained results indicate the impact of supply chain management on organizational performance and customer satisfaction.

RNAi and miRNA in Viral Infections and Cancers

Mollaie, Hamid Reza,Monavari, Seyed Hamid Reza,Arabzadeh, Seyed Ali Mohammad,Shamsi-Shahrabadi, Mahmoud,Fazlalipour, Mehdi,Afshar, Reza Malekpour Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Since the first report of RNA interference (RNAi) less than a decade ago, this type of molecular intervention has been introduced to repress gene expression in vitro and also for in vivo studies in mammals. Understanding the mechanisms of action of synthetic small interfering RNAs (siRNAs) underlies use as therapeutic agents in the areas of cancer and viral infection. Recent studies have also promoted different theories about cell-specific targeting of siRNAs. Design and delivery strategies for successful treatment of human diseases are becomingmore established and relationships between miRNA and RNAi pathways have been revealed as virus-host cell interactions. Although both are well conserved in plants, invertebrates and mammals, there is also variabilityand a more complete understanding of differences will be needed for optimal application. RNA interference (RNAi) is rapid, cheap and selective in complex biological systems and has created new insight sin fields of cancer research, genetic disorders, virology and drug design. Our knowledge about the role of miRNAs and siRNAs pathways in virus-host cell interactions in virus infected cells is incomplete. There are different viral diseases but few antiviral drugs are available. For example, acyclovir for herpes viruses, alpha-interferon for hepatitis C and B viruses and anti-retroviral for HIV are accessible. Also cancer is obviously an important target for siRNA-based therapies, but the main problem in cancer therapy is targeting metastatic cells which spread from the original tumor. There are also other possible reservations and problems that might delay or even hinder siRNA-based therapies for the treatment of certain conditions; however, this remains the most promising approach for a wide range of diseases. Clearly, more studies must be done to allow efficient delivery and better understanding of unwanted side effects of siRNA-based therapies. In this review miRNA and RNAi biology, experimental design, anti-viral and anti-cancer effects are discussed.

EXPERIMENTAL STUDY OF DESICCANT MATERIAL PRESSURE DROP

Hamdan Abdul Hamid,Chuah Siong Wei,Fathima Rehana Munas,Hamid Yusoff,Mohd Azmi Ismail 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

EXPERIMENTAL STUDY OF DESICCANT MATERIAL PRESSURE DROP

Hamdan Abdul Hamid,Chuah Siong Wei,Fathima Rehana Munas,Hamid Yusoff,Mohd Azmi Ismail 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11

Performance evaluation of a novel reactor configuration for oxidative dehydrogenation of ethane to ethylene

Hamid Asadi-Saghandi,Javad Karimi-Sabet 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.7

A one-dimensional non-isothermal steady state model was developed to simulate the performance of three-reactor configurations for the oxidative dehydrogenation of ethane (ODHE) to ethylene. These configurations consist of side feeding reactor (SFR), conventional fixed bed reactor (CFBR) and membrane reactor (MR). The performance of these reactors was compared in the terms of C2H6 conversion, C2H4 and CO2 selectivity and temperature profiles. The use of sectional air injections on the wall of SFR with a limited number of injection points showed that the performance of reactor significantly improves and optimum pattern of oxygen consumption is also obtained. Moreover, our SFR with a liquid coolant medium operates in an effectively controlled temperature profile that is comparable with that of the MR, which is cooled by a coolant stream of air. Hence, an enhancement in the level of selectivity is obtained for the SFR configuration. Consequently, the side feeding procedure can decrease the high operating temperature problem and low ethylene selectivity in the ODHE process. According to obtained results, the SFR would be a proper alternative for both the MR and CFBR.

Degradation of drag reducing polymers in aqueous solutions

Hamid Reza Karami,Masoud Rahimi,Saeed Ovaysi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

The performance of drag reducing polymers in turbulent flow is restricted by their mechanical degradation. This study examines how the working fluid can affect the degradation behavior of diluted drag reducing polymeric solutions. Solutions having different proportions of tap water and de-ionized water served as the working fluids. Three commercially available water soluble polymeric agents, namely, an anionic copolymer of polyacrylamide, xanthan gum, and polyethylene oxide, were then added to these solutions. All experiments had identical flow rates corresponding to turbulent conditions in a laboratory scale pipe line. Variation of pressure drop in the pipe line was then measured for 2 hours. It was found that polymer degradation is accelerated in tap water solutions compared to that in de-ionized water solutions. However, this is dependent on the specification of the polymer used, namely, the molecular weight of the polymer and the rigidity of its molecular backbone. Furthermore, a new mathematical relation has been developed to investigate degradation of the polymers over time.

Clinical Applications of Dual-Energy CT

Hamid Saira,Nasir Muhammad Umer,So Aaron,Andrews Gordon,Nicolaou Savvas,Qamar Sadia Raheez 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.6

Dual-energy CT (DECT) provides insights into the material properties of tissues and can differentiate between tissues with similar attenuation on conventional single-energy imaging. In the conventional CT scanner, differences in the X-ray attenuation between adjacent structures are dependent on the atomic number of the materials involved, whereas in DECT, the difference in the attenuation is dependent on both the atomic number and electron density. The basic principle of DECT is to obtain two datasets with different X-ray energy levels from the same anatomic region and material decomposition based on attenuation differences at different energy levels. In this article, we discuss the clinical applications of DECT and its potential robust improvements in performance and postprocessing capabilities.

Synthesis and employment of PEGDA for fabrication of superhydrophilic PVDF/PEGDA electrospun nanofibrous membranes by in-situ visible photopolymerization

Hamid Reza Ashjari,Arsalan Ahmadi,Mir Saeed Seyed Dorraji 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

A methodology for the synthesis of light curable poly(ethylene glycol) diacrylate (PEGDA) is described. PEGDA synthesis was confirmed using 1H NMR, 13C NMR, and infrared spectroscopy. The resin was used for fabrication of the superhydrophilic PVDF/PEGDA nanofibrous membrane in a single processing step. For the in-situ photo cross-linking reaction during electrospinning process, the electrospinning apparatus was equipped with a visible light source. Degree of conversion of double bonds during electrospinning process and interaction between the two polymers were investigated by FT-IR spectrum. To determine the potential applications of the as-prepared the membranes in wastewater treatment, parameters such as morphology, hydrophilicity and water resistance were investigated by scanning electron microscopy (SEM), tensile strength, static water contact angle (WCA) and Fourier transform infrared spectroscopy (FT-IR). The results showed that PVDF/PEGDA (40/60) nanofibrous membrane is superhydrophilic and insoluble in water.