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.

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.

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.

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

Observer-Based Mixed H₂/H<SUB>∞</SUB> Control Design for Linear Systems with Time-Varying Delays

Hamid Reza Karimi 대한전기학회 2008 International Journal of Control, Automation, and Vol.6 No.1

This paper presents a convex optimization method for observer-based mixed H₂/H∞ control design of linear systems with time-varying state, input and output delays. Delay-dependent sufficient conditions for the design of a desired observer-based control are given in terms of linear matrix inequalities (LMIs). An observer-based controller which guarantees asymptotic stability and a mixed H₂/H∞ performance for the closed-loop system of the linear system with time-varying delays is then developed. A Lyapunov-Krasovskii method underlies the observer-based mixed H₂/H∞ control design. A nwnerical example with simulation results illustrates the effectiveness of the methodology.

Solution of combined economic and emission dispatch problem using a novel chaotic improved harmony search algorithm

Hamid Rezaie,M.H. Kazemi-Rahbar,Behrooz Vahidi,Hasan Rastegar 한국CDE학회 2019 Journal of computational design and engineering Vol.6 No.3

This paper presents a new optimization technique developed based on harmony search algorithm (HSA), called chaotic improved harmony search algorithm (CIHSA). In the proposed algorithm, the original HSA is improved using several innovative modifications in the optimization procedure such as using chaotic patterns instead of uniform distribution to generate random numbers, dynamically tuning the algorithm parameters, and employing virtual harmony memories. Also, a novel type of local optimization is intro-duced and employed in the algorithm procedure. Applying these modifications to HSA has resulted in enhancing the robustness, accuracy and search efficiency of the algorithm, and significantly reducing the iterations number required to achieve the optimal solution. To validate the effectiveness of CIHSA, it is used to solve the combined economic emission dispatch (CEED) problem, which practically is a com-plex high-dimensional non-convex optimization task with several equality and inequality constraints. Six test systems having 6, 10, 13, 14, 40, and 140 generators are investigated in this study, and the valve-point loading effects, ramp rate limits and power transmission losses are also taken into account. The results obtained by CIHSA are compared with the results reported in a large number of other research works. Furthermore, the statistical data regarding the CIHSA performance in all test systems is presented. The numerical and statistical results confirm the high quality of the solutions found by CIHSA and its superiority compared to other existing techniques employed in solving CEED problems.

Some results on common best proximity point and common fixed point theorem in probabilistic Menger space

Hamid Shayanpour 대한수학회 2016 대한수학회지 Vol.53 No.5

In this paper, we define the concepts of commute proximally, dominate proximally, weakly dominate proximally, proximal generalized $\varphi$-contraction and common best proximity point in probabilistic Menger space. We prove some common best proximity point and common fixed point theorems for dominate proximally and weakly dominate proximally mappings in probabilistic Menger space under certain conditions. Finally we show that proximal generalized $\varphi$-contractions have best proximity point in probabilistic Menger space. Our results generalize many known results in metric space.

Earthquake effect on the concrete walls with shape memory alloy reinforcement

Hamid Beiraghi 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.4

Literature regarding concrete walls reinforced by super elastic shape memory alloy (SMA) bars is rather limited. The seismic behavior of a system concurrently including a distinct steel reinforced concrete (RC) wall, as well as another wall reinforced by super elastic SMA at the first story, and steel rebar at upper stories, would be an interesting matter. In this paper, the seismic response of such a COMBINED system is compared to a conventional system with steel RC concrete walls ( STEEL-Rein.) and also to a wall system with SMA rebar at the first story and steel rebar at other stories ( SMA-Rein.). Nonlinear time history analysis at maximum considered earthquake (MCE) and design bases earthquake (DBE) levels is conducted and the main responses like maximum inter-story drift ratio and residual inter-story drift ratio are investigated. Furthermore, incremental dynamic analysis is used to accomplish probabilistic seismic studies by creating fragility curves. Results demonstrated that the SMA-Rein. system, subjected to DBE and MCE ground motions, has almost zero and 0.27% residual maximum inter-story drifts, while the values for the COMBINED system are 0.25% and 0.51%. Furthermore, fragility curves show that using SMA rebar at the base of all walls causes a larger probability of exceedance 3% inter-story drift limit state compared to the COMBINED system. Static push over analysis demonstrated that the strength of the COMBINED model is almost 0.35% larger than that of the two other models, and its general post-yielding stiffness is also approximately twice the corresponding stiffness of the two other models.