A METHODOLOGY FOR CONDUCTING DESIGN TRADES FOR A SMALL SATELLITE LAUNCH VEHICLE WITH HYBRID ROCKET PROPULSION

The commercial space industry has recently seen a paradigm shift related to the launch of a small satellite into Low Earth Orbit. In the past, a small satellite was launched as a secondary payload with a medium or heavy launch vehicle where the primary payload placed a constraint on the orbit and schedule. Today, a dedicated launch of a small launch vehicle is the main operational concept to launch a small payload. Many Smallsat Launch Vehicles (SLV) have been under development by the commercial space industry to improve these launch services in recent years. Despite these efforts, the specific prices per launch are still high, and reducing these prices further remains a challenge. One promising technology candidate to reduce costs for SLV is hybrid rocket propulsion which has matured recently with some cost and safety advantages. Although hybrid rocket propulsion faces a number of challenges, including a low regression rate and combustion instabilities, academia and commercial companies have invested significant resources in developing this technology. With this motivation, this thesis has focused on the conceptual design of SLV with hybrid rocket propulsion. Moreover, a cost reduction strategy currently used by the commercial space industry was observed to be the development of a unique engine and using multiple of them in a launch vehicle. Following this trend, the vehicle concept investigated in this thesis was an expendable ground-launched vehicle with some architectural variables such as the number of stages and the number of hybrid motors in each stage. The design trade-off studies of such a small multistage launch vehicle with multiple hybrid motors in each stage require very long times especially when traditional point design approaches are used. As the number of design variables increase, the design space exploration becomes even more challenging. To provide a solution to this problem, a methodology for rapid conceptual design of such a vehicle was presented in this thesis. A physics-based conceptual design approach was followed in this study since SLV are relatively new concepts without much historical performance data. To conduct a multidisciplinary analysis, a physics-based, integrated modeling and simulation environment was constructed with four core disciplines: trajectory analysis, aerodynamics, propulsion, and weight. Aerodynamics and propulsion analysis were conducted using a first-principles approach, which was based on fundamental theories. A 3 Degree of Freedom (DOF) industrial, transparent, physics-based trajectory analysis software was used in this study based on availability. However, any other trajectory analysis software that a system designer is familiar with can be used in its place. In other words, the methodology developed in this thesis would remain unchanged if another trajectory analysis software were used. The weight discipline was represented at a high level by using Propellant Mass Fraction (PMF) design variable. A multidisciplinary modeling and simulation environment for launch vehicles may be computationally expensive depending on the fidelity levels of each discipline. Moreover, trajectory optimization is included in a launch vehicle design process conventionally which may be also computationally expensive depending on the optimization method. This expense poses a difficulty in performing a trade-off study for hundreds of vehicle design alternatives within the constraints of the schedule in the conceptual design phase. Because of this, trajectory optimization was removed from the design process to speed up the process by selecting a constant controller design. The methodology developed in this thesis consisted of two sequential steps. In the first step, a surrogate modeling approach was followed to replace the Modeling and Simulation (M&S) environment. A DOE method and a surrogate modeling method suitable to this problem were searched in this part. To cover the design space, a hybrid DOE consisting of a Fast Flexible Filling DOE and a three-level Full Factorial DOE was chosen. Artificial Neural Networks method was selected to fit approximation models because of the type of design variables (both continuous and discrete variables) and nonlinearity of the problem. The first experiment was conducted to test this hypothesis. As a result, it was demonstrated that this approach can provide accurate surrogate models for any desired response. In the second step, the specific mechanical energy-based design trade-off method was developed using some statistical methods. This method estimates the lower bound of the vehicles’ actual specific mechanical energy where the vehicles can be rapidly designed by using surrogate models. This lower bound was predicted with the help of the prediction interval of the specific mechanical energy’s model fit error. To fit the surrogate models, the necessary data were gathered by running the DOE in the integrated M&S environment while imposing some terminal conditions on the altitude of the vehicles analyzed in this environment. Specifically, the surrogate models of specific mechanical energy and flight path angle were used to design the vehicles rapidly. The second experiment was conducted to test this hypothesis. As a result, the actual specific mechanical energies computed via trajectory optimization were found to be consistent with the predictions. Overall, it was demonstrated that the proposed method enables a system designer to rapidly design some feasible vehicles, which can then proceed to the next design phase for further comparison, analysis, and design.M.S

Arthrogryposis Multiplex Congenita: Multiple Congenital Joint Contractures

Arthrogryposis multiplex congenita (AMC) is a syndrome characterized by nonprogressive multiple congenital joint contractures. The etiology of disease is multifactorial; it is most commonly suspected from absent fetal movements and genetic defects. AMC affects mainly limbs; also it might present with other organs involvement. It is crucial that the diagnosis of AMC should be kept in mind by musculoskeletal physicians in newborns with multiple joint contractures and patients must begin rehabilitation in early stage after accurate diagnosis in terms of functional independence. We present the diagnosis, types, clinical features, and treatment approaches of this disease in our case with literature reviews

Business against intimate partner violence; a case of participative action research and social action

This book is about the Business Against Domestic Violence (BADV) project, which has been initiated and coordinated by the Corporate Governance Forum of Turkey (CGFT) - a research center at Sabancı University’s School of Management, as a participatory action research project. The Project is aimed at exploring business agency in achieving gender equality through playing a catalytic role in mobilizing companies and business associations against IPV in Turkey in collaboration with the United Nations Population Fund (UNFPA) and the Turkish Industry and Business Association (TÜSİAD). Turkey represents an ideal setting for observing the role of business in achieving gender equality, as it has the highest gender gap amongst G-20 states following Saudi Arabia (WEF, 2018), the lowest labor force participation by women amongst all OECD countries (OECD, 2018), and a persistently high record of gender-based violence

Lithium promotes long-term neurological recovery after spinal cord injury in mice by enhancing neuronal survival, gray and white matter remodeling, and long-distance axonal regeneration

Spinal cord injury (SCI) induces neurological deficits associated with long-term functional impairments. Since the current treatments remain ineffective, novel therapeutic options are needed. Besides its effect on bipolar mood disorder, lithium was reported to have neuroprotective activity in different neurodegenerative conditions, including SCI. In SCI, the effects of lithium on long-term neurological recovery and neuroplasticity have not been assessed. We herein investigated the effects of intraperitoneally administered lithium chloride (LiCl) on motor coordination recovery, electromyography (EMG) responses, histopathological injury and remodeling, and axonal plasticity in mice exposed to spinal cord transection. At a dose of 0.2, but not 2.0 mmol/kg, LiCl enhanced motor coordination and locomotor activity starting at 28 days post-injury (dpi), as assessed by a set of behavioral tests. Following electrical stimulation proximal to the hemitransection, LiCl at 0.2 mmol/kg decreased the latency and increased the amplitude of EMG responses in the denervated hindlimb at 56 dpi. Functional recovery was associated with reduced gray and white matter atrophy rostral and caudal to the hemitransection, increased neuronal survival and reduced astrogliosis in the dorsal and ventral horns caudal to the hemitransection, and increased regeneration of long-distance axons proximal and distal to the lesion site in mice receiving 0.2 mmol/kg, but not 2 mmol/kg LiCl, as assessed by histochemical and immunohistochemical studies combined with anterograde tract tracing. Our results indicate that LiCl induces long-term neurological recovery and neuroplasticity following SCI.TUBA ; Istanbul Medipol University ; Turkish Academy of Science

Long-Term Outcome and Quality of Life of Patients with Unstable Pelvic Fractures Treated by Closed Reduction and Percutaneous Fixation

BACKGROUND Treatment of unstable pelvic fractures has evolved recently, and percutaneous treatment has become the choice of treatment in most cases. The aim of this study was to evaluate the outcome of percutaneous treatment in patients with unstable pelvic fractures. METHODS Twenty patients (11 females, 9 males; mean age, 32 years, range, 11-66 years) who had unstable pelvic fractures and were treated percutaneously were enrolled in the study. Short Form-36 (SF-36) scores, Majeed scores, Iowa Pelvic Scores, and Pelvic Outcome Scores were determined for the outcome assessment. RESULTS The minimum duration of follow-up was 2 years, (range, 24-48 months). The mean Injury Severity Score (ISS) was 31 (range, 16-50). The average SF-36 scores were comparable with the general population in terms of bodily pain, general health and social function. The mean Majeed functional pelvic score was 93.3 (range, 72-100; 19 excellent and 1 good clinical grades) and the mean Iowa Pelvic Score was 86 (range, 82-90). The mean Pelvic Outcome Score was 33 (range, 24-37; maximum score, 40). CONCLUSION We have demonstrated better outcomes in patients with pelvic fractures treated with percutaneous fixation. The technique may be advantageous as it avoids the use of extensive approaches, bleeding, wound complications, and prolonged surgeries.WoSScopu

WO3 decorated TiO2 nanotube array electrode: Preparation, characterization and superior photoelectrochemical performance for rhodamine B dye degradation

An efficient photoelectrocatalyst was synthesized by electrochemical deposition of WO3 on the titanium nanotube (TNT) array by subsequent cycling the potential between -0.6 - 1.0 V vs Ag/AgCl. The structural and morphological properties of the electrode obtained (TNT-WO3) was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques and it was revealed that TNT surfaces were successfully decorated by WO3 species without formation of another oxidation species. Then, the photoelectrocatalytic activity of the composite electrode set at 0.2 V (vs Ag/AgCl), was tested under UV light irradiation on the degradation of Methylene blue (MB), Orange G (OG) and Rhodamine B (RhB), as the model pollutants. Among the azo dyes studied, the electrode has given the best performance against RhB in comparison to the bare TNT electrode. The influence of the deposition conditions on the efficiency was examined and under optimal conditions and it was noted that efficient removal of the dye can be achieved within 10 min. Another advantage of the composite electrode is that PEC performance can be tuned by simply changing the parameters of deposition. (C) 2021 Elsevier B.V. All rights reserved.This study was supported by Ege University Scientific Research project no: 2018/FEN/036.Ege University Scientific Research project [2018/FEN/036

The Association between the Epicardial Adipose Tissue Thickness and Oxidative Stress Parameters in Isolated Metabolic Syndrome Patients: A Multimarker Approach

The risk for cardiovascular diseases and type 2 diabetes mellitus significantly increases in the patient population with metabolic syndrome (MeS). The present study aimed to investigate the association between the epicardial adipose tissue thickness (EATT) and the oxidative stress parameters in MeS patients. The study included 181 patients as a patient group of 92 consecutive patients with MeS and a control group of 89 consecutive patients with similar age and gender. EATT was evaluated by transthoracic echocardiography. Serum levels of total oxidant status (TOS), total antioxidative capacity (TAS), paraoxonase-1 (PON-1), and arylesterase activities were measured. EATT was higher in the MeS group compared to the control group (6.0 +/- 2.0 mm and 4.0 +/- 1.0 mm, resp.; P < 0.001). The level of TOS was higher in the MeS group compared to the control group (P < 0.001). Additionally, the TAS level was higher in the MeS group compared to the control group (P < 0.001). Furthermore, the serum levels of PON-1 and arylesterase were lower in the MeS group compared to the control group (P < 0.001). EAT may cause an increased risk of cardiovascular diseases by leading to increased oxidative stress in patients with MeS

The Association between the Epicardial Adipose Tissue Thickness and Oxidative Stress Parameters in Isolated Metabolic Syndrome Patients: A Multimarker Approach

The risk for cardiovascular diseases and type 2 diabetes mellitus significantly increases in the patient population with metabolic syndrome (MeS). The present study aimed to investigate the association between the epicardial adipose tissue thickness (EATT) and the oxidative stress parameters in MeS patients. The study included 181 patients as a patient group of 92 consecutive patients with MeS and a control group of 89 consecutive patients with similar age and gender. EATT was evaluated by transthoracic echocardiography. Serum levels of total oxidant status (TOS), total antioxidative capacity (TAS), paraoxonase-1 (PON-1), and arylesterase activities were measured. EATT was higher in the MeS group compared to the control group (6.0 ± 2.0 mm and 4.0 ± 1.0 mm, resp.; P<0.001). The level of TOS was higher in the MeS group compared to the control group (P<0.001). Additionally, the TAS level was higher in the MeS group compared to the control group (P<0.001). Furthermore, the serum levels of PON-1 and arylesterase were lower in the MeS group compared to the control group (P<0.001). EAT may cause an increased risk of cardiovascular diseases by leading to increased oxidative stress in patients with MeS

Xenogenic neural stem cell-derived extracellular nanovesicles modulate human mesenchymal stem cell fate and reconstruct metabolomic structure

Abstract Extracellular nanovesicles, particularly exosomes, can deliver their diverse bioactive biomolecular content, including miRNAs, proteins, and lipids, thus providing a context for investigating the capability of exosomes to induce stem cells toward lineage-specific cells and tissue regeneration. In this study, it is demonstrated that rat subventricular zone neural stem cell-derived exosomes (rSVZ-NSCExo) can control neural-lineage specification of human mesenchymal stem cells (hMSCs). Microarray analysis shows that the miRNA content of rSVZ-NSCExo is a faithful representation of rSVZ tissue. Through immunocytochemistry, gene expression, and multi-omics analyses, the capability to use rSVZ-NSCExo to induce hMSCs into a neuroglial or neural stem cell phenotype and genotype in a temporal and dose-dependent manner via multiple signaling pathways is demonstrated. The current study presents a new and innovative strategy to modulate hMSCs fate by harnessing the molecular content of exosomes, thus suggesting future opportunities for rSVZ-NSCExo in nerve tissue regeneration