ESTIMATING THE VALUE OF THE VOLUME FROM ACCELERATION ON THE DIAPHRAGM MOVEMENTS DURING BREATHING

Information related to the movements of the diaphragm is very important and it is used in the detection of some respiratory diseases, which are common in all over the world, such as chronic obstructive pulmonary disease (COPD), asthma, and bronchitis. This article describes a practical method for estimating the value of the volume using the acceleration information on the diaphragm movements. The main goal of this paper is to develop a data collection system that measures acceleration values and to estimate the acceleration-volume relationship by examining the obtained data. Thus, two important parameters (TVC and FVC) in the diagnosis of COPD are measured in a more practical way. In the present case, these two parameters can be measured in a hospital environment by an expensive medical device called “spirometry”. For this purpose, our device is placed on the abdomen region of the patient, diaphragm movements are examined and values of the volume are estimated from acceleration data (total 416 accelerometric data). Measurements are performed simultaneously by the spirometry and the developed device. Pearson coefficient (p<0.01) is calculated to determine the correlation between the measured data by using devices. Results show us that there is a positive correlation between measured values of the two devices (accelerometric and spirometric). It can be concluded that there is an acceptable correlation (91.4%) between accelerometric and spirometric results and the estimate error margin is quite low (0.08). In this respect, this study is considered to be an alternative method to spirometry tests, which is used in diagnosing COPD

Fabrication of vertically aligned Pd nanowire array in AAO template by electrodeposition using neutral electrolyte

A vertically aligned Pd nanowire array was successfully fabricated on an Au/Ti substrate using an anodic aluminum oxide (AAO) template by a direct voltage electrodeposition method at room temperature using diluted neutral electrolyte. The fabrication of Pd nanowires was controlled by analyzing the current–time transient during electrodeposition using potentiostat. The AAO template and the Pd nanowires were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) methods and X-Ray diffraction (XRD). It was observed that the Pd nanowire array was standing freely on an Au-coated Ti substrate after removing the AAO template in a relatively large area of about 5 cm2, approximately 50 nm in diameter and 2.5 μm in length with a high aspect ratio. The nucleation rate and the number of atoms in the critical nucleus were determined from the analysis of current transients. Pd nuclei density was calculated as 3.55 × 108 cm−2. Usage of diluted neutral electrolyte enables slower growing of Pd nanowires owing to increase in the electrodeposition potential and thus obtained Pd nanowires have higher crystallinity with lower dislocations. In fact, this high crystallinity of Pd nanowires provides them positive effect for sensor performances especially

Güç yükselticilerinde arakipleme bozulumundaki bakışımsızlığın ve hafıza etkisinin modellenmesi.

This dissertation is focused on developing a new passband behavioral model in order to account for asymmetric intermodulation distortion resulted from memory effect. First, a measurement setup is prepared to measure the AM/AM, AM/PM distortion, magnitudes and the phases of intermodulation (IMD) and fundamental (FUND) components which are created by the amplifier where phase is calculated only by measuring magnitudes. Then, responses of a sample amplifier are measured for different excitation situations (center frequency and tone spacing are swept). A new modeling technique, namely Odd Order Modeling (OOM), is proposed which has unequal time delay terms. The reason of unequal time delay addition is the change of effective channel length according to the average power passing through that channel. These unequal delays create asymmetry in the IMD components. General Power Series Expansion (GPSE) model is also extracted, OOM and GPSE model performances are compared by using NMSE metric. In order to improve model performance, even order terms with envelope of input are added. It is mathematically proven that even order terms with envelope of the input have contribution to IMD and FUND components’. This improved version of modeling is named as Even Order modeling (EOM). EOM model performance is compared with the others’ performance for two-tone excitation measurement results. It is shown that EOM gives the most accurate result. Model performance is checked for unequal four-tone signal as well. EOM model is applied to baseband DPD circuit after making some modifications. Model linearization performance is compared with the performances of the other memory polynomial modeling techniques.Ph.D. - Doctoral Progra

4G C-Şeklinde açıklıklı kompakt mikroşerit anten tasarımı ve üretimi

Bu çalışmada, mikrodalga erişim için dünya çapında birlikte çalışılabilirlik (WiMAX) uygulamasına uyumlu bir monopol anten sunulmuştur. Önerilen anten WiMAX’e uygun olan 3.43-3.61 GHz frekans aralığında çalışmaktadır. Anten, FR4 plaka üzerinde 33.25 x 33.25 x 1.6 mm3 boyutlarında üretilmiştir. Anten kazanç, ışıma paterni ve s parametreleri açısından analiz edilmiştir. S parametreleri yapılan ölçüm sonuçları ile doğrulanmıştır. Elde edilen sonuçlar göstermiştir ki sunulan antenin önceden literatürde yayınlanan antenlere kıyasla çalışma bandı ve geri dönüş kaybı gibi anten karakteristikleri daha iyidir

A low-order nonlinear amplifier model with distributed delay terms

In this paper, a novel behavioral modeling technique for the characterization of memory effects of amplifiers is proposed. This characterization utilizes asymmetric intermodulation distortion (IMD)components, which are the result of a 2-tone excitation of a nonlinear amplifier. These asymmetric IMD components are represented basically by a power series, where each term in the series has its own time delay term. These time delay terms successfully justify the presence of asymmetry in the intermodulation components, which leads to the prediction of amplitude-to-amplitude and amplitude-to-phase distortions. The parameters of the model are extracted using 2-tone measurements. A 100-W peak power amplifier is examined. Model predictions are verified by the measurement results of a 4-tone stimulus. The proposed model can also be used in time domain analysis with arbitrary excitation

Production of Submicron Alumina Powder by Sol-Gel Method

Bu çalışmada çeşitli alüminyum mBetali; kaynaklarından yola çıkarak, alüminyum alkoksitten sol-jel yöntemi ile mikronaltı incelikte alümina toz üretimi amaçlanmıştır. Üretim yöntemi olarak sol-jel yönteminin kullanılmasının nedeni; daha düşük sıcaklıklarda sinterlenebilen, homojen ve mikronaltı incelikte taneler içeren tozların üretimine imkan veren kimyasal bir yöntem olmasıdır. Sol-jel yöntemi; kimyasal bir proses olup, jelleşebilen solüsyon veya süspansiyonlara dayalıdır. Bu yöntemde metal alkoksitler ve metal tuzlan uygun bir çözücüde çözülüp, su ve katalizör yardımıyla hidroliz ve polimerizasyon reaksiyonları oluşturulur. Bu reaksiyonların kontrolü ile toz ürünler elde edilir. Bu çalışmada sol-jel yöntemi kullanarak, mikronaltı incelikte alümina toz üretilmiştir.Sol-gel is a chemical process which depends on solutions and suspansions that are easily turn into gel form. In this method, metallic alkoxide and metallic salts are dissolved in a suitable solvent. Then, with the aid of waterand catalyst, hydrolysis and polimerisation reactions occur. By cotrolling the reactions, powder products are obtained. In this study, submicron alümina powder is produced by using sol-gel method

Statistical Analysis of Electromagnetic Shielding Effectiveness of Metal Fiber Blended Fabrics

In this paper the electromagnetic shielding effectiveness (EMSE) of knitted fabrics made of copper, silver and stainless steel blended conductive yarns were analyzed statistically. Data obtained by the experiments carried out in 1.7 - 2.6GHz frequency band with the help of waveguide system was evaluated by statistical methods. A total of 29 different knitted fabric samples were used in the experiments, including rib, weft, milano, lacoste and cardigan types. In order to test the stability of shielding effectiveness (SE) descriptive statistics were presented for all fabric samples. Subsequently, data was distributed into clusters by means of ANOVA method. In this way, the fabrics with the worst and best shielding performance were found at 95% confidence level. The statistical findings overlapped with experimental results

Memory polynomial with shaped memory delay profile and modeling the thermal memory effect

This paper presents a proposal for a new memory polynomial modeling technique with non-uniform delay taps to capture the thermal memory effects in power amplifiers. In the proposed modeling structure, each order of the memory polynomial is assigned a different memory delay. The delay profile is an exponentially shaped function, instead of equal unit delays for all memory polynomial branches. Three different metrics, the memory effect modeling ratio (MEMR) and the normalized mean square error (NMSE) and spectrum error (SE) are used to benchmark the proposed exponentially shaped delay profile memorial polynomial model performance against previously published models, namely the memoryless, the unit delay and sparse delay memory based polynomial models. The model coefficients of four models are extracted for three different excitation signals, which were selected as a 64-QAM signal around 2.14 GHz with 20 kHz, 30 kHz and 40 kHz bandwidths, ensuring that the thermal memory effects dominate the electrical memory effects. It is shown that the proposed model outperforms all the previously published models for all three excitation signals used in the experiment