Realization of Low-Voltage Modified CBTA and Design of Cascadable Current-Mode All-Pass Filter

In this paper, a low voltage modified current backward transconductance amplifier (MCBTA) and a novel first-order current-mode (CM) all-pass filter are presented. The MCBTA can operate with ±0.9 V supply voltage and the total power consumption of MCBTA is 1.27 mW. The presented all-pass filter employs single MCBTA, a grounded resistor and a grounded capacitor. The circuit possesses low input and high output impedances which make it ideal for current-mode systems. The presented all-pass filter circuit can be made electronically tunable due to the bias current of the MCBTA. Non-ideal study along with simulation results are given for validation purpose. Further, an nth-order cascadable all-pass filter is also presented. It uses n MCBTAs, n grounded resistors and n grounded capacitors. The performance of the proposed circuits is demonstrated by using PSPICE simulations based on the 0.18 µm TSMC level-7 CMOS technology parameters

Biotribology of Artificial Hip Joints

Tribology is the science of interacting surfaces; when these surfaces are in a biological system, it is called as biotribology. With the increasing rate of joint replacement operations and need for artificial prosthesis, biotribology is becoming a very important and rapidly growing branch of tribology. Based on this fact, in this chapter, basic tribological concepts are presented in terms of friction, lubrication, and wear; then with these fundamental backgrounds the biotribological behavior of natural and artificial hip joints are discussed in detail. Moreover, material pairs that are used in artificial joint replacements and the application of surface modification for the enhancement of the tribological properties of these materials are handled. Furthermore, the determination of tribological behavior of joint materials such as wear, coefficient of friction, friction torque, and frictional heating by using conventional techniques and hip joint simulator are discussed. Finally, the measurement and analysis of wear in both retrieved prosthesis and experimental studies are discussed referring the latest research articles

Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs

Current-mode (CM) and voltage-mode (VM) multiphase sinusoidal oscillator (MSO) structures using current backward transconductance amplifier (CBTA) are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd) equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm) of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters

Novel Floating General Element Simulators Using CBTA

In this study, a novel floating frequency dependent negative resistor (FDNR), floating inductor, floating capacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The presented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable for fully integrated circuit design. The circuit does not require any component matching conditions, and it has a good sensitivity performance with respect to tracking errors. Moreover, the proposed FDNR, inductance, capacitor and resistor simulator can be tuned electronically by changing the biasing current of the CBTA or can be controlled through the grounded resistor or capacitor. The high-order frequency dependent element simulator circuit is also presented. Depending on the passive component selection, it realizes high-order floating circuit defining as V(s) = snAI(s) or V(s) = s-nBI(s). The proposed floating FDNR simulator circuit and floating high-order frequency dependent element simulator circuit are demonstrated by using PSPICE simulation for 0.25 μm, level 7, TSMC CMOS technology parameters

Primjena metode odzivnih površina i neuronskih mreža za modeliranje i procjenu otpornosti na abrazijsko trošenje Poly oxy metilena

In this study, abrasive wear behaviour of poly oxy methylenes (POM) under various testing conditions was investigated. A central composite design (CCD) was used to describe response and to estimate the parameters in the model. Response surface methodology (RSM) was adopted to obtain an empirical model of wear loss as a function of applied load and sliding distance. Also, a neural network (NN) model was developed for the prediction and testing of the results. Finally, a comparison was made between the results obtained from RSM and NN.U radu je istraživano abrazijsko trošenje poly oxy metilena (POM), za različite uvjete ispitivanja. Za procjenu parametara modela i odziva, primijenjen je centralno kompozitni plan pokusa. Primjenom metode odzivnih površina dobiven je matematički model ovisnosti gubitka mase o primijenjenom opterećenju i putu klizanja. Također, primjenom neuronskih mreža, razvijen je model za procjenu i testiranje rezultata. Na kraju su uspoređeni rezultati modela, dobiveni metodom odzivnih površina i primjenom neuronskih mreža

Analysis and Optimization of Process Parameters in Wire Electrical Discharge Machining Based on RSM: A Case Study

In this book chapter a review and critical analysis on current research trends in wire electrical discharge machining (WEDM) and relation between different process parameters including pulse on time, pulse off time, servo voltage, peak current, dielectric flow rate, wire speed, wire tension on different process responses include material removal rate (MRR), surface roughness (Ra), sparking gap, wire lag and wire wear ration (WWR) and surface integrity factors was investigated. On the basis of critical evaluation of the available literature following conclusions are summarized. In addition, different modeling and optimization methods used in WEDM were discussed and a case study based on response surface method (RSM) including design of experiment (DoE) carried out to find optimal process parameters effect on surface roughness was conducted. In the final part of the present study was presented some recommendations about the trends for future WEDM researches

Synthesis and Properties of Inulin Based Microgels

AbstractCross-linked inulin (X-inulin) microparticles were synthesized in reverse micelles using water-in-oil microemulsion polymerization. Linear inulin was crosslinked with divinyl sulfone (DVS) in a sodium bis(2-ethylhexyl) sulfosuccinate (AOT) inverse microemulsion under basic conditions. These particles were demonstrated to be excellent scaffolds for the in situ synthesis of CdS quantum dots (Q-dots). The inulin-based particles were shown to be non-cytotoxic in fibroblast cell culture, and degradable under acidic and basic conditions. Furthermore, gallic acid and caffeine were used as model drugs for loading and release studies from these particles, illustrating their potential as drug carriers with controlled release

A New Approach for Measurement of The Efficiency of Cpm and Cpmk Control Charts

[EN] Process capability analysis is a very effective way for improving process quality by relating process variation to customer requirements. It compares the output of a process to the specification limits by using process capability indices (PCIs). PCIs provide numerical measures on whether aprocess conforms to the defined manufacturing capability prerequisite. In this paper, a new approach based on non-central Chi-Square, ¿ and ¿ distributions is presented to design the capability control charts. The main purpose of this work is to investigate the efficiency of the proposed control charts comparing with the traditional control charts. The advantage of using the proposed capability control charts is that, the practitioner can monitor the process mean and the process variability by looking at one chart. Moreover the proposed capability control charts are easily appended to X-R control chart and provide judgments considering the ability of a process to meet requirements. To demonstrate the applicability of the proposed approach an illustrative example is conducted.Carot Sánchez, MT.; Sagbas, A.; Sanz Juan, JM. (2013). A New Approach for Measurement of The Efficiency of Cpm and Cpmk Control Charts. International Journal for Quality Research. 7(4):605-622. http://hdl.handle.net/10251/99672S6056227

Universal Filter Using Single Commercially Available IC: LT1228

In electrical and electronic engineering, the filter is very importance circuit. A voltage-mode three inputs single output second-order multifunction filter is presented in this paper. The proposed filter is based on RLC parallel circuit. The main active element is the commercially available IC from Linear Technology Inc, LT1228. The filter consists of single LT1228, single resistor and two capacitors. Five output second-order filter responses, namely band-pass (BP), band-stop (BS), high-pass (HP), low-pass (LP) and all-pass (AP) functions are achieved. Each output response can be selected without component matching condition and the requirement of double gain amplifier. The quality factor and natural frequency can be electronically controlled. PSpice simulation results suing macro model of LT1228 are in close agreement with the theory

Role of sympathetic cotransmitter galanin on autonomic balance in heart failure: an active player or a bystander?

Objective: Galanin, a cotransmitter similar to neuropeptide Y (NPY), aggravates autonomic imbalance in systolic heart failure (HF) by attenuating vagal tonus after burst sympathetic activity. In animal HF models, galanin antagonists have improved cardiac function. To determine whether galanin is a promising therapeutic target in HF, we studied its concentrations in HF patients and evaluated its correlation with NPY, markers of humoral activity such as pro-BNP and copeptin, and echocardiographic parameters of HF severity. Methods: After recording demographic and echocardiographic characteristics of 87 individuals (57 HF patients and 30 control subjects), fasting serum concentrations of galanin, NPY, copeptin, and pro-BNP were determined. Results: Unlike pro-BNP, copeptin, and NPY, which were significantly elevated in HF patients (p<0.001, p<0.001, and p=0.001, respectively), galanin was similar in HF patients and control subjects (p=0.9). NPY correlated with the echocardiographic parameters of HF severity (r=-0.22, p=0.03 for EF; r=0.3, p=0.005 for Tei index of RV; r=-0.23, p=0.03 for TAPSE; and r=0.24, p=0.024 for E/e') and pro-BNP (r=0.22, p=0.046). NPY levels were also associated with beta blocker (BB) use, wherein BB significantly decreased NPY in both HF patients and control subjects. Galanin correlated with humoral biomarkers, pro-BNP and copeptin (r=0.39, p<0.001 and r=0.41, p<0.001, respectively). Although current smoking, BB therapy, pro-BNP, copeptin, and body mass index were associated with galanin in univariate analyses, the multiple linear regression model revealed that pro-BNP was the only significant determinant of galanin levels in HF patients. Conclusion: Our findings confirmed the role of NPY in autonomic balance and suggest that galanin is associated with the proadrenergic state, but its role in HF in humans remains unclear.Scientific Research Projects Fund of Namik Kemal University [NKUBAP.02.YL.16.046]This research was supported by the Scientific Research Projects Fund of Namik Kemal University (NKUBAP.02.YL.16.046)