Triangular signal stabilization of nonlinear systems

Many nonlinear systems display self-sustained oscillations which are often undesirable. The stabilizing effect of a high frequency input signal on an oscillating system with one nonlinearity is determined by the characteristics of the nonlinear element in the system, the linear portion of the system and the amplitude of the signal. This investigation has been concerned with the effect of a triangular wave stabilizing signal on these self oscillations. The equivalent gains for several common nonlinearities are derived. The pseudo describing function introduced by Oldenburger and Boyer for sinusoidal stabilization has been extended to the triangular wave case, and it is shown that the pseudo describing function for an odd nonlinearity is real. The pseudo describing function is used in an analysis similar to describing function analysis in order to predict the existence and amplitude of the self oscillation of a triangular wave stabilized, closed loop, nonlinear system. The experimental results are in close agreement with the predictions of the theory --Abstract, page ii

Isolation and characterization of lactic acid bacteria from gastrointestinal tract of snakehead (channa striatus, bloch) as probiotic for freshwater fish

The intensive application of antibiotics to prevent and control the bacterial diseases in aquaculture has resulted in development of antibiotic-resistant bacteria. Therefore, probiotics as an alternative strategy have been suggested to be used as replacement for antimicrobial drugs and growth promoters. Lactic acid bacteria (LAB) constitute a group of G+ve bacteria with a high ability to produce antibacterial compounds and improve fish performance which makes them excellent probiotics. In the present study, snakehead (Channa striatus), an indigenous commercial freshwater fish in Southeast Asia countries was chosen for the isolation of LAB. Isolates obtained on de Man Rogosa and Sharp (MRS) agar and broth showed 27 and 9 pure isolates from the fingerling and adults fishes, respectively. According to the antagonistic plate test against Aeromonas hydrophila as a main freshwater fish pathogen, five LABs i.e. three isolates from the fingerlings and two from the adults that showed the greatest inhibition zone were selected. The selected LABs were identified as Aerococcus viridans, Lactobacillus delbreuckii sp. delbreuckii and Enterococcus faecalis from fingerlings and Lactobacillus fermentum and Leuconostoc mesenteroides sp.mesenteroides from adult fish. Probiotic property evaluation of LAB candidates showed that they could survive and grow at pH 3 up to 8 (P < 0.05). They could also tolerate bile salt concentrations from 0.0 to 0.3% (P < 0.05). The LABs were active at different levels of NaCl (0.0 to 4%) and also, at various temperatures ranging from 15 oC to 45 oC, but showed no growth at 10 oC and 50 oC. Antagonistic effects against three tested fish pathogens i.e. A. hydrophila, Pseudomonas aeruginosa and Shewanella putrefaciens indicated that En. faecalis, L. fermentum and Leu. mesenteroides sp. mesenteroides had the highest inhibition activities. The antibiotic sensitivity test showed that En. faecalis had more antibiotic’s resistance property against some antibiotics as compared to other LAB (P < 0.05). According to probiotic characterization as screening, En. faecalis, L. fermentum and Leu. mesenteroides were selected for in vivo experiments. The viability of LABs in feed stored at 4 oC was higher than 25 oC during four weeks storage.Significant increased of the LAB proportion was observed in the fish intestine fed LAB-fortified diets as compared to the control group (P < 0.05). In addition, the lower G-ve bacteria population in the fish intestine was observed for experimental groups as compared to the control group. Effects of mono and multi-species of LAB candidates on the body composition of Javanese carp (Puntius gonionotus) indicated that LAB-fortified diets could not seriously affect the chemical composition of experimental fish carcasses. The survivability was the same for all experimental groups. The concentration of 107 cfu/g diets was overall more effective than 105 and 109 cfu/g diets. The use of En.faecalis as probiotic had more positive effects than L. fermentum and Leu.mesenteroides on growth, feed conversion ratio, specific growth rate, and protein efficiency ratio (P < 0.05). Moreover, the use of En. faecalis resulted in an increase in the production of protease and lipase enzymes in the digestive tract of Javanese carp. Results obtained from the short chain fatty acid determination which included acetate, propionate and butyrate showed that treated group with En. faecalis could significantly (P < 0.05) enhance the propionate and butyrate production as compared to the control. An in vivo challenge test of A. hydrophila as a fish pathogen with En. faecalis as a probiotic on Javanese carp indicated that this probiotic could protect the fish against A. hydrophila and showed a higher survivability compared to the control. The presence of En. faecalis in the diet could affect immune response to enhance the antibody level as a humoral response. The fish treated with a LAB-fortified diet (En. faecalis) and added pathogen (A. hydrophila) into the water showed the highest antibody level as compared to the control group (P > 0.05). In conclusion, LABs can be normal microbiota in the gastrointestinal tract of the snakehead. In addition, the use of En. faecalis as a probiotic had positive effects on overall fish performance, digestive enzymes and short chain fatty acid production, survivability in challenge with pathogen and increased humoral immune response in Javanese carp. This LAB as an environmental friendly agent can be suggested as an alternative to antibiotics in freshwater fish culture

Computational Techniques to Predict Orthopaedic Implant Alignment and Fit in Bone

Among the broad palette of surgical techniques employed in the current orthopaedic practice, joint replacement represents one of the most difficult and costliest surgical procedures. While numerous recent advances suggest that computer assistance can dramatically improve the precision and long term outcomes of joint arthroplasty even in the hands of experienced surgeons, many of the joint replacement protocols continue to rely almost exclusively on an empirical basis that often entail a succession of trial and error maneuvers that can only be performed intraoperatively. Although the surgeon is generally unable to accurately and reliably predict a priori what the final malalignment will be or even what implant size should be used for a certain patient, the overarching goal of all arthroplastic procedures is to ensure that an appropriate match exists between the native and prosthetic axes of the articulation. To address this relative lack of knowledge, the main objective of this thesis was to develop a comprehensive library of numerical techniques capable to: 1) accurately reconstruct the outer and inner geometry of the bone to be implanted; 2) determine the location of the native articular axis to be replicated by the implant; 3) assess the insertability of a certain implant within the endosteal canal of the bone to be implanted; 4) propose customized implant geometries capable to ensure minimal malalignments between native and prosthetic axes. The accuracy of the developed algorithms was validated through comparisons performed against conventional methods involving either contact-acquired data or navigated implantation approaches, while various customized implant designs proposed were tested with an original numerical implantation method. It is anticipated that the proposed computer-based approaches will eliminate or at least diminish the need for undesirable trial and error implantation procedures in a sense that present error-prone intraoperative implant insertion decisions will be at least augmented if not even replaced by optimal computer-based solutions to offer reliable virtual “previews” of the future surgical procedure. While the entire thesis is focused on the elbow as the most challenging joint replacement surgery, many of the developed approaches are equally applicable to other upper or lower limb articulations

Developing a conceptual model of customer loyalty using meta-synthesis

The following research is the base for loyalty formation in current conditions where many profitable opportunities from enterprises have still remained unknown or not completely identified. Application and management of customer loyalty system is a powerful and important strategy for customer-orientation in any enterprise. Customer loyalty enables enterprises to achieve a higher efficiency using such strategy and provide more favorite services by spending less time and cost. The main goal of this study is to realize reasons of weak performance in the previous researches conducted on loyalty during the last three decades. Identification of basic and determinant factors in applicability of studies on loyalty is now accounted for a valuable research. The first step involves pathology of the earlier studies about loyalty. The present work has thus been done to identify the existing condition of previous studies using meta-synthesis qualitative method. Research tools are past deeds and documents in this field which include total number of 27 researches. Method of research is data analysis based on open code. The obtained results have shown that 28 identified loyalty codes can be categorized under 11 main factors. Finally, the required recommendations will be made accordingly

Development of a Centrifugal Distributor Having Vertical Disproportionate Blades for Granular Particles

Agricultural Engineerin

PROVIDING A COMPREHENSIVE MODEL TO MEASURE THE PERFORMANCE DIMENSIONS OF INDUSTRIAL CLUSTERS USING THE HYBRID APPROACH OF Q-FACTOR ANALYSIS AND CLUSTER ANALYSIS

One of the most important development strategies with the emphasis on small and medium industries is the geographical concentration of production units and the formation of cluster. The industrial cluster is a globally economic phenomenon that has been proposed as a modern model for economic development. Theoretically, an industrial cluster can strengthen specialized sectors and facilitate industrial cooperation. The aim of this study was to provide a comprehensive model for measuring the performance dimensions of industrial clusters in Markazi province using a hybrid approach of Q-factor analysis and cluster analysis. For this purpose, at first and in the first phase of the research, 41 effective factors in the clustering of the performance dimensions of the statistical population were identified with the study of previous research and the use of Q-factor analysis, and in the second phase, a model for comprehensive performance measurement of industrial clusters was presented using cluster analysis in R software. The results of the study indicated that industrial clusters in Markazi province have four financial, competitive, economic and environmental performance dimensions

Rapid and simultaneous genotypic detection of Rifampin-Isoniazid and Ethambutol resistant Mycobacterium tuberculosis by use of MAS-PCR

AbstractAims and objectivesThis study aims to identify common mutations leading to Isoniazid (INH), Rifampin (RMP) and Etambutol (EMB) resistance using Multiplex Allele-Specific Polymerase Chain Reaction (MAS-PCR).MethodIn a cross-sectional study during 2012–2013, 257 patients with smear-positive pulmonary tuberculosis residing in five frontier west and north-west provinces of Iran were evaluated in respect of common point mutations leading to resistance to tree first-line drugs.ResultsThe overall frequency of mutations was 37 out of which 8 mutations were related to katG 315, 26 mutations pertained to rpoB 516, 526 and 531 and 3 mutations related to emb B. The rpoB single, double and triple mutations were found in 45.3%, 42.3% and 15.4% of rpoB, respectively. Frequency of patients with mutation to katG and at least one rpoB codon was 7cases (2.7%) at the same time. In this study 60.0% of INH-resistant and 83.3% of RMP-resistant isolates were detected by MAS-PCR technique. Mutation odds were higher in females and in patients with a history of anti-TB drug use.ConclusionThe MAS-PCR is a relatively rapid, sustainable, efficient and accurate technique for detection of drug resistance in tuberculosis. This highlights also the role of mutation at inhA, ahp and oxy R genes in the creation of IHN resistance which may be the causative factor in the remainder of cases

Перинатология. Настоящее и будущее

На основании обобщения многолетнего собственного опыта автора, данных литературы и результатов работы Московского центра планирования семьи и репродукции освещены актуальные проблемы перинатологии от пренатального периода до постнатальной охраны здоровья плода. Сделано заключение о необходимости и возможности создания стандартов в области лечебных мероприятий и тактики ведения родов при осложнениях.Basing on the generalization of many−year experience as well as the data of the literature and results of the work of Moscow Center for Family Planning and Reproduction, the author features the urgent issues of perinatology from prenatal period to postnatal health protection. The author concludes about the necessity and possibility to create the standards in the field of therapeutic measures and management tactics in complicated delivery