Investigation of a non-linear suspension in a quarter car model

This thesis presents the study of a quarter car model which consists of a two-degree-of-freedom (2 DOF) with a linear spring and a nonlinear spring configuration. In this thesis, the use of non-linear vibration attachments is briefly explained, and a survey of the research done in this area is also discussed. The survey will show what have been done by the researches in this new field of nonlinear attachments. Also, it will be shown that this topic was not extensively researched and is a new type of research where no sufficient experimental work has been applied. As an application, a quarter car model was chosen to be investigated. The aim of the Thesis is to validate theoretically and experimentally the use of nonlinear springs in a quarter car model. Design the new type of suspension and insert it in the experimental set up, built from the ground up in the laboratory. A novel criterion for optimal ride comfort is the root mean square of the absolute acceleration specified by British standards ISO 2631-1997. A new way to reduce vibrations is to take advantage of nonlinear components. The mathematical model of the quarter-car is derived, and the dynamics are evaluated in terms of the main mass displacement and acceleration. The simulation of the car dynamics is performed using Matlab® and Simulink®. The realization of vibration reduction through one-way irreversible nonlinear energy localization which requires no pre-tuning in a quarter car model is studied for the first time. Results show that the addition of the nonlinear stiffness decreases the vibration of the sprung mass to meet optimal ride comfort standards. As the passenger is situated above the sprung mass, any reduction in the sprung mass dynamics will directly have the same effect on the passenger of the vehicle. The future is in the use of a nonlinear suspension that could provide improvement in performance over that realized by the passive, semi active and active suspension. The use of a quarter car model is simple compared to a half car model or a full car model, furthermore in the more complex models you can study the heave and the pitch of the vehicle. For the initial study of the nonlinear spring the quarter car model was sufficient enough to study the dynamics of the vehicle. Obtaining an optimum suspension system is of great importance for automotive and vibration engineer involved in the vehicle design process. The suspension affects an automobile’s comfort, performance, and safety. In this thesis, the optimization of suspension parameters which include the spring stiffness and damper coefficient is designed to compromise between the comfort and the road handling. Using Genetic algorithm an automated optimization of suspension parameters was executed to meet performance requirements specified. Results show that by optimizing the parameters the vibration in the system decreases immensely

Nanofluid: New Fluids by Nanotechnology

Recently, nanotechnology has played a major part in multifields of heat transfer processes and developed a remarkable progress in the energy applications. One of the most plausible applications of nanotechnology is to produce nanoparticles of high thermal conductivity and mixing with the base fluids that transfer energy forming what is called nanofluids. Adding of nanoparticles to the base fluid shows a remarkable enhancement of the thermal properties of the base properties. Nanotechnology has greatly improved the science of heat transfer by improving the properties of the energy-transmitting fluids. A high heat transfer could be obtained through the creation of innovative fluid (nanofluids). This also reduces the size of heat transfer equipment and saves energy

Novel therapeutic approach for regulating the susceptibility of epitheliato adenovirus infection

Human Adenoviruses (AdVs) are etiologic agents for respiratory tract, digestive tract, heart, and eye infections. Although most AdV infections are self-resolving, some infections progress to acute respiratory disease with up to 50% mortality, particularly in immunosuppressed people. Except for vaccines for serotypes, 4 and 7, serotypes that are prevalent in the military, no vaccines or therapeutics that specifically prevent or treat AdV infection exist. On the other hand, AdV remains the most common vector system used in gene therapy clinical trials worldwide and several AdV vectors show promise in phase III clinical trials. The majority of AdVs use the coxsackievirus and adenovirus receptor (CAR) as a primary receptor. We have characterized an alternatively spliced eight-exon containing isoform (CAREx8) that localizes at the apical surface of epithelial cells and is responsible for the initiation of apical AdV infection. A cellular scaffold protein named Membrane Associated Guanylate Kinase, WW and PDZ Domain Containing 1 (MAGI-1) directly interacts with and alternatively regulates CAREx8 through the C-terminal PDZ-binding domain. The alternative regulation is due to the interaction with two different domains, namely PDZ1 and PDZ3, within the same molecule (MAGI-1). I hypothesized that cell permeable peptides that target the interaction between MAGI-1 PDZ1 domain and CAREx8 (TAT-PDZ1) would be able to decrease CAREx8 protein levels and prevent AdV infection. On the other hand, peptides that target the interaction between MAGI-1 PDZ3 domain and CAREx8 (TAT-PDZ3) would be able to increase CAREx8 and enhance AdV mediated gene therapy. Decoy peptides that target the assigned domain were synthesized and conjugated to TAT cell permeable peptide to facilitate peptide entry (TAT-PDZ1; TAT-NET1, TAT-E6) or (TAT-PDZ3; TAT-CAREx8-9c, TAT-ESAM). Peptide entry into the polarized epithelia was confirmed by mass spectroscopy and fluorescence microscopy. Treatment with TAT-PDZ1 peptides decreased the cellular levels of CAREx8 and suppressed AdV transduction in MDCK, human airway epithelia (HAE), as well as epithelia from cotton rats, an animal model of AdV pathogenicity. To determine the mechanism of peptide action, CAREx8 localization was tracked by immunofluorescence. Interestingly, TAT-PDZ1 caused nuclear translocation of CAREx8 C-term domain, an effect that was reversed by ADAM17 inhibitor (TIMP3) and ¿-secretase inhibitor (Comp E), implicating the regulated intramembrane proteolysis (RIP) pathway. Immunoprecipitation and direct ligand binding assays showed that ADAM17 interacts specifically with MAGI-1 PDZ2 domain, suggesting that TAT-PDZ1 peptides caused CAREx8 degradation by enhancing the proximity of the substrate (CAREx8) and enzyme (ADAM17). Finally, ADAM17 caused CAREx8 extracellular domain (ECD) shedding that was able to significantly decrease AdV-GFP transduction, indicating a second protective role against AdV entry by the shed ECD of CAREx8. By contrast, TAT-PDZ3 peptides increased the levels of CAREx8 and significantly increased AdV entry and transduction in MDCK, HAE, and cotton rat epithelia. Upon TAT-PDZ3 peptide administration, CAREx8 was localized in vesicular pattern compartments distinct from MAGI-1 and spread throughout the apical trafficking pathway and at the apical surface of the epithelium. Investigation of the trafficking pathway of CAREx8 using Rabs reveal the possibility of CAREx8 is residing within the recycling Endosomal-Golgi pathway. Neither TAT-PDZ1 nor TAT-PDZ3 binding peptides altered epithelium formation, as measured by transepithelial resistance (TER) as well as dextran permeability across the epithelia, indicating the safety of the peptides on epithelial integrity. Moreover, intranasal administration of TAT-PDZ3 peptides increased AdV transduction by 300-500% while TAT-PDZ1 peptides decreased AdV transduction by 80-95% after intrana..

Estradiol and ascorbic acid alleviate malathion-induced lung damage in albino Wistar rats: A histopathological study

Aim: To assess the modulatory role of estradiol and ascorbic acid in malathion-induced pulmonary toxicity in albino Wistar rats. Methods: A total of twenty albino Wistar rats were randomly divided into four groups; the control group (group 1) was given corn oil alone, the test group (group 2) received a daily dose of malathion 20 mg/kg in corn oil, treatment group A (group 3) was administered a daily dose of malathion 20 mg/kg in corn oil plus estradiol 40 µg/100 g (gram), and treatment group B (group 4) received a daily dose of malathion 20 mg/kg in corn oil plus ascorbic acid 100 mg/kg. Experimental rats were administered once daily for four weeks. The lungs were examined histopathologically using two staining methods (Hematoxylin and Eosin, Masson Trichrome). Results: There were significant reductions in degeneration, interstitial pneumonia and interstitial fibrosis for group 3 (treatment group A) compared to group 2 (test group) (p<0.05). These reductions were more statistically significant for group 4 (treatment group B) compared to group 2 (test group) (p<0.01). Therefore, the damage was less pronounced and injury severity was moderate in group 3 treated with estradiol. Group 4, with ascorbic acid, showed the most improvement with significant tissue repair under microscopic examination and mild injury compared to group 3. Conclusions: The results of our present study suggest that both estradiol and ascorbic acid have clear protective effects against malathion-induced lung injury. However, ascorbic acid exhibited more pronounced protective effects compared to estradiol. With more comprehensive studies, the positive effects of ascorbic acid and estradiol can be used to prevent lung damage in individuals exposed to malathion

Obituary announcements in Jordanian and British newspapers: A cross-cultural overview

This paper examines the socio-cultural practices surrounding the use of obituary announcements in two different cultures. Specifically, it investigates the structural and linguistic features as well as the euphemistic expressions related to death in obituaries placed in Jordanian and British newspapers. It aims at exploration of the impact of some sociological factors on the form and content of the obituaries as well as finding out the communicative functions conveyed by this particular means of communication. The data comprise three hundred (300) death announcements evenly distributed by the two societies under investigation. The data were analyzed quantitatively and qualitatively. The paper reveals clear-cut differences between the two sets of obituaries in terms of structure, language and function. It has also been observed that most of these differences are mainly attributable to socio-cultural distinctions between the two societies. This study elicited a number of significant results which are full of insights to sociolinguistic theory and which lead to a better understanding of the interrelated relationship between language and culture.This paper examines the socio-cultural practices surrounding the use of obituary announcements in two different cultures. Specifically, it investigates the structural and linguistic features as well as the euphemistic expressions related to death in obituaries placed in Jordanian and British newspapers. It aims at exploration of the impact of some sociological factors on the form and content of the obituaries as well as finding out the communicative functions conveyed by this particular means of communication. The data comprise three hundred (300) death announcements evenly distributed by the two societies under investigation. The data were analyzed quantitatively and qualitatively. The paper reveals clear-cut differences between the two sets of obituaries in terms of structure, language and function. It has also been observed that most of these differences are mainly attributable to socio-cultural distinctions between the two societies. This study elicited a number of significant results which are full of insights to sociolinguistic theory and which lead to a better understanding of the interrelated relationship between language and culture

The Exponentiated Generalized Power Generalized Weibull Distribution: Properties and Applications

This paper introduces a new flexible extension of power generalized Weibull distribution which contains many life-time distributions as sub-models. The hazard rate function of the proposed distribution is useful and suitable for monotone and non-monotone hazard behaviors that are more likely to be observed in real-life situations. Statistical properties of the new model are studied including; quantile, moment generating, reliability, hazard, and reverse hazard functions. Further, the moments, incomplete moments, mean deviations, Bonferroni and Lorenz curves, order statistics densities are derived. The maximum likelihood estimation method is used to estimate the distribution parameters. The effectiveness and usefulness of the new distribution are accomplished through four different real-life applications

Enhanced Torsion Mechanism of Small-Scale Reinforced Concrete Beams with Spiral Transverse Reinforcement

The nonlinear torsional behaviour of small-scale reinforced concrete (RC) beams with continuous staggered spiral as transverse reinforcement stirrups is experimentally investigated. Twelve miniatures RC beams were tested under torsion load considering the closed shape of stirrups and compared with continuous staggered spiral ones. All miniatures beams were scaled down to be one-eighth the prototype beam size. The main parameters considered in this research are stirrup spacing and its configurations. Small scale RC beams were taken into account in the existing study because of their construction simplicity and financial feasibility. Mortar without coarse aggregate was applied instead of concrete to reduce the size effect of applying small scale models. Ongoing research trials have been carried out to obtain an efficacious approach to boost torsion failure mechanisms because brittle torsion failure of RC structural elements should be avoided. This study emphasized boosted torsion capacity, dissipated energy, and helical crack propagation. During testing, the primary cracking torsion moment, ultimate torsion moment, peak twist angle, and failure mechanism of the beams were inspected. The use of spiral stirrups showed great enhancement of the torsional behaviour of samples. It was observed that using spiral stirrups rather than closed stirrups could result in a substantial increase in torsion capacity and dissipated energy of 87.7% and 89.8%, respectively. As a result, the predicted capacities of the RC beams prototype were estimated in detail, taking account the scale down factor implemented by the authors. Values obtained based on international specifications and guidelines were used to compare the experimental results. Doi: 10.28991/CEJ-2022-08-11-019 Full Text: PD

Benign prostatic hyperplasia: Enucleation versus resection using plasmakinetic energy: a prospective randomized study at Zagazig University Hospital

Background: Transuretheral resection of the prostate (TURP) has been the gold standard endoscopic treatment for bladder outlet obstruction (BOO) secondary to benign prostatic hyperplasia (BPH). New technologies have been developed to minimize the morbidity of TURP. Recently, the Gyrus Plasma Kinetic (PK) System is the first bipolar device used in urological practice, as a new modality in treatment of BPH.Objective: To evaluate the efficacy and safety of plasmakinetic enucleation compared to plasmakinetic resection of the prostate in the management of BOO induced by BPH. Patients and Methods: This study was conducted on 58 volunteers from Department of Urology, Faculty of Medicine, Zagazig University between January 2018, and January 2020. Patients were randomized to either plasmakinetic enucleation of the prostate (PKEP) group or plasmakinetic resection of the prostate (PKRP) group. All patients were indicated for surgical treatment (prostate size ≥ 60 g and ≤ 120 g). Results: There were no statistically significant differences between the two groups preoperatively. PKEP resulted in a greater volume of prostatic tissue removal than the PKRP. Tissue retrieved/total operative time in PKEP group was greater than in PKRP group (0.69 gm/min vs 0.67 gm/min respectively). The mean indwelling uretheral catheter time was shorter in PKEP group (34.7 ±4.40 hrs.) than in PKRP (48.79 ±4.31 hrs.). Regarding postoperative complication (early and late), there were no statistically significant differences between the two groups.Conclusions: We concluded that regarding, surgical safety and efficacy PKEP is comparable to PKRP for prostates (60-120 ml). Either PKEP or PKRP can be on an equal footing to TURP as an endoscopic management of BP

Mining Event Traces from Real-time Systems for Anomaly Detection

Real-time systems are a significant class of applications, poised to grow even further as autonomous vehicles and the Internet of Things (IoT) become a reality. The computation and communication tasks of the underlying embedded systems must comply with strict timing and safety requirements as undetected defects in these systems may lead to catastrophic failures. The runtime behavior of these systems is prone to uncertainties arising from dynamic workloads and extra-functional conditions that affect both the software and hardware over the course of their deployment, e.g., unscheduled firmware updates, communication channel saturation, power-saving mode switches, or external malicious attacks. The operation in such unpredictable environments prevents the detection of anomalous behavior using traditional formal modeling and analysis techniques as they generally consider worst-case analysis and tend to be overly conservative. To overcome these limitations, and primarily motivated by the increasing availability of generated traces from real-time embedded systems, this thesis presents TRACMIN - Trace Mining using Arrival Curves - which is an anomaly detection approach that empirically constructs arrival curves from event traces to capture the recurrent behavior and intrinsic features of a given real-time system. The thesis uses TRACMIN to fill the gap between formal analysis techniques of real-time systems and trace mining approaches that lack expressive, human-readable, and scalable methods. The thesis presents definitions, metrics, and tools to employ statistical learning techniques to cluster and classify traces generated from different modes of normal operation versus anomalous traces. Experimenting with multiple datasets from deployed real-time embedded systems facing performance degradation and hardware misconfiguration anomalies demonstrates the feasibility and viability of our approaches on timestamped event traces generated from an industrial real-time operating system. Acknowledging the high computation expense for constructing empirical arrival curves, the thesis provides a rapid algorithm to achieve desirable scalability on lengthy traces paving the way for adoption in research and industry. Finally, the thesis presents a robustness analysis for the arrival curves models by employing theories of demand-bound functions from the scheduling domain. The analysis provides bounds on how much disruption a real-time system modeled using our approach can tolerate before being declared anomalous, which is crucial for specification and certification purposes. In conclusion, TRACMIN combines empirical and theoretical methods to provide a concrete anomaly detection framework that uses robust models of arrival curves scalably constructed from event traces to detect anomalies that affect the recurrent behavior of a real-time system