Investigation of Orthogonal Frequency Division Multiplexing Based Power Line Communication Systems

Power Line Communication (PLC) has the potential to become the preferred technique for providing broadband to homes and offices with the advantage of eliminating the need for new wiring infrastructure and reducing the cost. Power line grids, however, present a hostile channel for data communication, since the fundamental purpose of the power line channel was only the transmission of electric power at 50/60 Hz frequencies. The development of PLC systems for providing broadband applications requires an adequate knowledge of the power line channel characteristics. Various types of noise and multipath effects are some of the limitations for power line channels which need to be considered carefully in designing PLC systems. An effect of an impulsive noise characterized with short durations is identified as one of the major impairment in PLC system. Orthogonal Frequency Division Multiplexing (OFDM) technique is one of the modulation approaches which has been regarded as the modulation technique for PLC systems by most researchers in the field and is used in this research study work. This is because it provides high robustness against impulsive noise and minimizes the effects of multipath. In case of impulsive noise affecting the OFDM system, this effect is spread over multiple subcarriers due to Discrete Fourier Transform (DFT) at the receiver. Hence, each of the transmitted communication symbols is only affected by a fraction of the impulsive noise. In order to achieve reliable results for data transmission, a proper power line channel with various noise models must be used in the investigations. In this research study work, a multipath model which has been widely accepted by many researchers in the field and practically proven in the Tanzanian power line system is used as the model for the power line channel. The effects of different scenarios such as variations in direct path length, path number, branch length and load on the channel frequency response are investigated in this research work. Simulation results indicate the suitability of multi-carrier modulation technique such as an OFDM over the power line channels. To represent the actual noise scenario in the power line channel, an impulsive noise and background noise are classified as the two main noise sources. A Middleton class A noise is modelled as an impulsive noise, whereas the background noise is modelled as an Additive White Gaussian Noise (AWGN). The performance of PLC system based on OFDM is investigated under Middleton Class A and AWGN noise scenarios. It is observed that Bit Error Rate (BER) for the impulsive noise is higher than the background noise. Since channel coding can enhance the transmission in a communication system, Block code and convolutional codes have been studied in this research work. The hamming code chosen as a type of the block code, whereas the Trellis Coded Modulation (TCM) selected from the category of the convolutional channel codes and modelled in Matlab2013b. Although TCM code produces improvements in the Signal-to-Noise Ratio (SNR), they do not perform well with Middleton class A noise. A rectangular 16-QAM TCM based on OFDM provides better BER rate compared to the general TCM

Factors affecting cellulase sorption in soil

The sorption of cellulase proteins of Trichoderma viride on calcareous soils was investigated, and the soil factors affecting cellulase sorption were also studied. The study on some arid, semiarid and humid soils of Isfahan, Hamadan and Gilan provinces of Iran revealed that the sorption of cellulase on the calcareous soils obey both the Freundlich and the Langmuir isotherms. The maximum binding levels of cellulase on the Isfahan, Hamadan and Gilan soils estimated by the Langmuir model were 58.72, 41.64 and 74.07 g kg-1, respectively. The association binding constants were 3.32, 2.17 and 1.86 ml mg-1 for cellulase sorption on the Isfahan, Hamadan and Gilan soils, respectively. The observed differences may be due to the deferent clay and carbonate contents of soils, because the correlation tests revealed that the sorption capacity of soils was significantly related to the soil clay and carbonates contents. Cellulase sorbed on the soils was not correlated with soil organic mater contents. Sorbed cellulase washed out more easily from the Hamadan soils than from the other soils, probably due to their lower clay contents.Keywords: Sorption, calcareous soils, cellulas

T-duality/plurality of BTZ black hole metric coupled to two fermionic fields

We ask the question of classical super (non-)Abelian T-duality for BTZ black hole metric coupling to two fermionic fields. Our approach is based on super Poisson-Lie (PL) T-duality in the presence of spectator fields. In order to study the Abelian T-duality of the metric we dualize over the Abelian Lie supergroups of the types $(1|2)$ and $(2|2)$, in such a way that it is shown that both original and dual backgrounds of the models are conformally invariant up to one-loop order in the presence of field strength. Then, we study the non-Abelian T-duality of the BTZ vacuum metric coupling to two fermionic fields. The dualizing is performed on some non-Abelian Lie supergroups of the type $(2|2)$, in such a way that we are dealing with semi-Abelian superdoubles which are non-isomorphic as Lie superalgebras in each of the models. In the non-Abelian T-duality case, it is interesting to mention that the models can be conformally invariant up to one-loop order in both cases of the absence and presence of field strength. In addition, starting from the decomposition of semi-Abelian Drinfeld superdoubles generated by some of the {\C}^3 \oplus {\A}_{1,1} Lie superbialgebras we study the super PL T-plurality of the BTZ vacuum metric coupled to two fermionic fields. However, our findings are interesting in themselves, but at a constructive level, can prompt many new insights into supergravity and manifestly have interesting mathematical relationships with double field theory.Comment: 39 pages, 7 Table

Novel silver-doped NiTiO3: auto-combustion synthesis, characterization and photovoltaic measurements

Novel silver-doped nickel titanate nanoparticles (Ag-NiTiO3) were successfully prepared via a sol-gel method in the presence of stearyl alcohol as the capping agent and solvent. The formation of pure crystallized nickel titanate and silver-doped nickel titanate was occurred when the precursor was heat-treated at 700 °C in air for 150 and 60 min, respectively. The structural, morphological, and optical properties of obtained products were characterized by techniques such as X-ray diffraction (XRD), Fourier transforminfrared (FT-IR) spectroscopy, Energy dispersive X-ray microanalysis (EDX), ultraviolet-visible (UV-vis), and scanning electron microscopy (SEM). The magnetic property of the prepared Ag-NiTiO3 nanoparticles was also investigated with vibrating sample magnetometer (VSM). To fabricate a FTO/TiO2/Ag-NiTiO3/Pt-FTO solar cell, Ag-NiTiO3 film was directly deposited on top of the TiO2 prepared by electrophoresis deposition method. Furthermore, solar cell result indicates that an inexpensive solar cell could be developed by the synthesized Ag-NiTiO3 nanoparticles.Keywords: Ag-NiTiO3, sol-gel method, semiconductor, photovoltaic, dopin

Bit Error Rate performance in Power Line Communication Channels with Impulsive Noise

The performance of Power Line Communication (PLC) degrades due to the presence of different types of noise interferences generated by electrical appliances. This paper investigates the bit-error rate (BER) performance of a higherorder 64-QAM constellation with orthogonal frequency multiplexing modulation (OFDM) in presence of impulsive noise modelled as Middleton Class A over a multipath PLC. It is observed that BER for the impulsive noise is higher than the background noise. The BER further deteriorates on increasing the level of the impulsive noise, even while being injected into the PLC channel at a lower rate. Investigations would assist applying methods to mitigate and reduce the effect of impulsive noise over PLC systems for higher constellations with a view to increase the data rates

Data transfer over low-voltage European power distribution networks

Broadband power line (BPL) data transmission deals with transfer of data via the existing power line systems and is a fast emerging technology. The main advantage of BPL is being able to use the existing power line infrastructure, thereby reducing the cost. However, power line systems were not designed for high-speed data transmission as they consist of various branches and power line elements such as bridges, taps, transformers and capacitor banks. Therefore, the power line transmission medium not only introduces noise but is also adverse to high-speed data transfer in terms of the channel bandwidth. In this paper a power line channel has been modelled using Matlab and the effects of variations in the direct length, branch length and branch load on the channel frequency response are investigated. Simulations indicate suitability of multi-carrier transmission over the power line channels

Complicações das intervenções dos bancos de ossos locais em pacientes ortopédicos internados no Hospital Imam Khomeini em Urmia durante o segundo semestre de 2015 e acompanhamento do resultado do tratamento pelo médico ortopedista

Local bonesetters are part of the health system in many developing countries. Their acceptability is beyond the boundaries of social classes and religious educations and beliefs. The objective of this research is to evaluate the causes of people admission to local bonesetters and the complications of local bonesetters' interventions in orthopedic patients and to follow-up the outcome of their treatment. In a prospective study with follow-up, patients' demographic information, complications of bonesetters' interventions, the reason for patients' admission to these individuals, the cost spent in this process and the delayed time for admission of these people to medical specialized services were collected. Data were analyzed by SPSS 21 software. In this research, a total of 61 patients were examined, which 28 (45.9%) of the patients stated that they would admit to bonesetter in the case of re-fracture. The main reason to admit to bonesetter among the patients was low cost of admission to bonesetter in 20 cases (32.8%), belief in better treatment by bonesetter in12 cases (19.7%), lack of trust in medical system in 7 cases (11.5%), recommendation of acquaintances and friends in 13 cases (21.3%), and short period of treatment by bonesetter in 9 cases (14.8%). This rate of admission to local bonesetter is directly correlated to the socioeconomic level of patients. Specialized orthopedic remedial measures following local bonesetters' interventions sometimes lead to failure and lack of recovery.Los sobanderos locales forman parte del sistema de salud en muchos países en desarrollo. Su aceptabilidad está más allá de los límites de las clases sociales y las enseñanzas y creencias religiosas. El objetivo de esta investigación es evaluar las causas de la admisión de personas a los sobanderos locales y las complicaciones de las intervenciones locales de las personas que arreglan fracturas en pacientes ortopédicos y hacer un seguimiento del resultado de su tratamiento. En un estudio prospectivo con seguimiento, la información demográfica de los pacientes, las complicaciones de las intervenciones de sobanderos, la razón por la cual los pacientes ingresaron a estas personas, el costo invertido en este proceso y el tiempo de demora para la admisión de estas personas a servicios médicos especializados fueron recogidos. Los datos fueron analizados por el software SPSS 21. En esta investigación, se examinaron un total de 61 pacientes, de los cuales 28 (45,9%) de los pacientes declararon que admitirían el sobandero en caso de fractura. La principal razón para admitir que los pacientes tenían mala conducta era el bajo costo del ingreso en 20 casos (32.8%), la creencia en un mejor tratamiento por parte de los sobanderos en 12 casos (19.7%), la falta de confianza en el sistema médico en 7 casos (11.5%)., recomendación de conocidos y amigos en 13 casos (21,3%), y corto período de tratamiento con sobanderos en 9 casos (14,8%). Esta tasa de ingreso al huesero local está directamente relacionada con el nivel socioeconómico de los pacientes. Las medidas de remediación ortopédicas especializadas después de las intervenciones locales a veces llevan al fracaso y a la falta de recuperación.Os desossadores locais fazem parte do sistema de saúde em muitos países em desenvolvimento. Sua aceitabilidade está além dos limites das classes sociais e dos ensinamentos e crenças religiosos. O objetivo desta pesquisa é avaliar as causas da internação de pessoas nos consertos locais e as complicações de intervenções locais de pessoas que fixam fraturas em pacientes ortopédicos e monitorar os resultados de seu tratamento. Em um estudo de acompanhamento prospectivo, informações demográficas dos pacientes, as complicações de intervenções hueseros, a razão pela qual os pacientes foram admitidos a essas pessoas investiram neste atraso de custos e tempo de processo para a admissão destes pessoas para serviços médicos especializados foram coletadas. Os dados foram analisados pelo software SPSS 21. Nessa investigação, foram examinados 61 pacientes, dos quais 28 (45,9%) dos pacientes declararam que admitiriam o preparador de ossos em caso de fratura. O principal motivo para admitir que os pacientes apresentavam mau comportamento foi o baixo custo de admissão em 20 casos (32,8%), a crença em melhor tratamento por parte dos consertadores de ossos em 12 casos (19,7%), a falta de confiança na sistema médico em 7 casos (11,5%). ), recomendação de conhecidos e amigos em 13 casos (21,3%), e curto período de tratamento com fixadores de ossos em 9 casos (14,8%). Essa taxa de internação para o organizador de ossos local está diretamente relacionada ao nível socioeconômico dos pacientes. Medidas especializadas de remediação ortopédica após intervenções locais às vezes levam ao fracasso e à falta de recuperação

Using online image processing technique for measurement the browning in banana during drying (a new and automatic method)

Determination and controlling of quality parameters can be useful for ordering and marketing of fruits.  Color is the first and the most important parameter in the visual appearance of fruits, specifically in banana.  The aim of this study is to use image-processing technique (online operation) to measure and analyze the color change of banana slices during thin layer drying.  Using online-image-processing technique resulted in designing a machine vision system to control the color change of products automatically.  The results show a linear relation with high correlation coefficient for L*, a* and b* (0.967, 0.962 and 0.991 respectively) between the data of the image-processing technique and the hold-hand colorimeter.  In this study, parameters of chroma, hue and browning index were determined to describe the kinetics of color change in banana slices.  The change of chroma was not significant, but hue was decreased and browning index was increased during drying time.  In addition, the experimental data of the L* and ∆E was fitted using zero and first order models with high correlation coefficient (0.80-0.97).   Keywords: image processing, machine vision, online, banan