Effects of prolonged heating on antioxidant activity and colour of honey

The kinetics of changes in total antioxidant activity as assessed by DPPH radical and brown pigment formation (BPF) in honey heated at different temperatures (50, 60 and 70 °C) for up to 12 days were studied. Antioxidant activity and BPF increased with treatment temperature and time. BPF increased following zero-order kinetics with the activation energy value of 122 kJ/mol⁻¹ at 50–70 °C. However, antioxidant activity variation showed different trends according to heating temperatures following second-order, first-order and zero-order kinetics at 50, 60 and 70 °C, respectively. Heating of honey at 70 °C was found to be more effective than 50 and 60 °C for both two parameters. The results demonstrated that antioxidant activity was correlated with increased browning of the samples.     

A new wireless asynchronous data communications module for industrial applications

All the sensors such as temperature, humidity, and pressure used in industry provide analog outputs as inputs for their control units. Wireless transmission of the data has advantages on wired transmission such as USB port, parallel port and serial port and therefore has great importance for industrial applications. In this work, a new wireless asynchronous data communications module has been developed to send the earth magnetic field data around a ferromagnetic material detected by a KMZ51 AMR sensor. The transmitter module transmits the analog data obtained from a source to a computer environment where they are stored and then presented in a graphical form. In this design, an amplitude shift keying (ASK) transceiver working at the frequency of 433.92 MHz which is a frequency inside the so called Industrial Scientific Medical band (ISM band) used for wireless communications. The analog data first fed into a 10-bit ADC controlled by a PIC microcontroller and then the digital data is sent to the transmitter. A preamble bit string is added in front of the data bits and another bit string for achieving synchronization and determination the start of the data is used. The data arriving at the receiver is taken by the microcontroller and sent to a LCD display as well as the serial port of a computer where it is written in a text file. A Visual Basic based graphics interface is designed to receive, store and present the data in the form of graphical shapes. In the paper, all the work has been explained in detail.     

Functionalization of low molecular weight atactic polypropylene Part I. Spectroscopic studies

Summary Low molecular weight atactic polypropylene (APP) was functionalized with 4-allyl-2-methoxyphenol (eugenol), 4-allyl-1,2-dimethoxybenzene (DMAB), 4-propenylanisole(trans-anethole), cis-2,4,5-trimethoxypropenylbenzene (β-asarone) and 4-allyl-2,6-dimethoxyphenol (ADMP) in the presence of dicumyl peroxide (DCP) at 170°C. Amount of grafted eugenol, DMAB and anethole on APP and characterization of the products were carried by UV-VIS and FTIR spectroscopies respectively. The effects of the reaction time, concentrations of the functional compounds and DCP on the extent of grafting were examined. Received: 8 June 1999/Revised version: 31 August 1999/Accepted: 31 August 1999     

Phenolic composition of European cranberrybush (Viburnum opulus L.) berries and astringency removal of its commercial juice

Phenolic composition of the European cranberrybush (ECB) (Viburnum opulus L.) juice was determined using high‐performance liquid chromatography. The juice contained 2037 mg kg^?1 chlorogenic acid, which was 54% of total phenolics, and several other phenolics such as (+)‐catechin, (?)‐epicatechin, cyanidin‐3‐glucoside, cyanidin‐3‐rutinoside and six different glucosides of quercetin. Because of its strong astringent taste, the juices were treated with various doses of two different types of activated carbons (Granucol Bi and Granucol Ge) in order to remove phenolic compounds. Results revealed that both types of activated carbons were equally effective on astringency removal (P < 0.01). A 20–30% reduction in total phenolics was achieved by application of 2.0–3.0 g L^?1 activated carbon which also removed unpleasant taste and odour.     

A Novel Cross-layer Routing Protocol for Increasing Packet Transfer Reliability in Mobile Sensor Networks

In mobile sensor networks (MSNs), sensor data is generally transferred via mobile sensor nodes by multi-hop fashion. Because of the mobility of the nodes in the network, the efficient routing protocols are needed to ensure end-to-end route reliability while incurring minimal power consumption and packet delay. In this study, we developed a new routing protocol to meet these requirements for MSNs based on a cross-layer interaction among five reference layers (application, transport, network, MAC and physical). The proposed protocol primarily exploits the idea of interaction among these five layers all-in-one protocol. Its primary goals are (i) to discover the most reliable route in network, (ii) to sustain the route reliability and (iii) to be energy efficient and delay aware. It has been designed, modeled and simulated by using OPNET Modeler simulation software. The simulation results of the proposed protocol have been compared to three well known routing protocols (i.e., AODV, Leach-Mobile, CBR-Mobile). According to the obtained results, the proposed protocol outperforms its counterparts in terms of route reliability and end-to-end delay performances.     

Design and determination of stator geometry for axial flux permanent magnet free rod rotor synchronous motor

During designing a new axial flux permanent magnet free rod rotor synchronous motor, it is important to know before hand in which phase the largest angular velocity can occur, what is the ways to reduce the power consumption, how to achieve to increase or decrease the rotation speed by changing the core geometry. Therefore, presenting these preliminary information that are necessary for the design of a free rod rotor synchronous motor to the researchers is the aim of this work. In this respect, this study presents the design and geometrical dimensions of the stator for a new synchronous motor which is an axial flux permanent magnet free rod machine with three, four, five and six phases. This type of motors are an innovative approach especially for the applications used in industrial stirrers. Each type of stator is designed such that it has an appropriate number of phases. The rotating magnetic field over the stator is established by a PIC based microcontroller feeding the interface circuit to the stator wounds. The maximum angular speeds of bar magnet rotors with four different lengths and masses are calculated theoretically and determined experimentally. In addition, the effects of the distance between the rotor and stator, the angular speed of the rotor within the limits of the operation, and the volume of the liquid to be stirred to the power applied are investigated. Furthermore, the effects of the lengths and angular speeds of the bar magnet rotors to the distance between the rotor and stator are determined. In the light of the information obtained and taking into account the power used, the most appropriate parameters and variables such as the stator geometry changing with the phase used, the length of rotor, the distance between the rotor and stator and the angular speeds of rotor are determined.     

Determining optimum tilt angles and orientations of photovoltaic panels in Sanliurfa, Turkey

The performance of a photovoltaic (PV) panel is affected by its orientation and its tilt angle with the horizontal plane. This is because both of these parameters change the amount of solar energy received by the surface of the PV panel. A mathematical model was used to estimate the total solar radiation on the tilted PV surface, and to determine optimum tilt angles for a PV panel installed in Sanliurfa, Turkey. The optimum tilt angles were determined by searching for the values of angles for which the total radiation on the PV surface was maximum for the period studied. The study also investigated the effect of two-axis solar tracking on energy gain compared to a fixed PV panel. This study determined that the monthly optimum tilt angle for a PV panel changes throughout the year with its minimum value as 13° in June and maximum value as 61° in December. The results showed that the gains in the amount of solar radiation throughout the year received by the PV panel mounted at monthly optimum tilt angles with respect to seasonal optimum angles and tilt angel equal to latitude were 1.1% and 3.9%, respectively. Furthermore, daily average of 29.3% gain in total solar radiation results in an daily average of 34.6% gain in generated power with two-axis solar tracking compared to a south facing PV panel fixed at 14° tilt angle on a particular day in July in Sanliurfa, Turkey.     

1,5 Tesla MRI in focal nodular hyperplasia. Review of the literature apropos of 7 cases

There are increasing reports of unusual clinical features and atypical courses of syphilis in patients with acquired immunodeficiency syndrome. Recently, we had the opportunity to study an HIV-positive female patient with strong manifestations of secondary syphilis. The case is discussed together with the implications of secondary syphilis in her concomitant ocular affliction. Moreover, we comment on the clinico-therapeutic controversies brought about by the association of infection with Treponema pallidum and HIV.     

Kaposi sarcoma of the lungs in patients with acquired immunodeficiency syndrome (AIDS). Thoracic radiography and scanning

Twenty-four patients with AIDS presenting with Kaposi's sarcoma of the lung were retrospectively studied to assess the merits of thoracic radiographs and of CT for the diagnosis of this disease. Evidence for Kaposi's sarcoma of the lung was given by a characteristic fiberendoscopic appearance in 10 cases and by the histologic diagnosis in 14 cases. All patients had chest radiographs and 14 patients a concomitant thoracic CT study. Chest radiographs showed perihilar opacities in 18 patients, nodules in 8, mediastinal and/or hilar adenopathies in 2 and pleural effusion in 16. Comparison of the patients who had had thoracic radiographs and a CT scan showed better detection of adenopathies, described in 2 cases on chest radiographs and 7 on CT scans, and of nodules, detected in 5 cases on chest radiographs and 6 on CT scans. In 12 patients with perihilar opacities on thoracic radiographs, CT provided a better view of the peribronchovascular distribution of these opaque areas. In 1 patient, CT showed peribronchovascular thickening while radiographs were normal. In 1 patient, both examinations were normal. This study emphasizes the merits of thoracic radiographs and, even more, of CT for the diagnosis of Kaposi's sarcoma of the lung. Peribronchovascular thickening appears to be a characteristic sign that is well analyzed with computed tomography. Since histological evidence of Kaposi's sarcoma is rarely obtained because of the aggressive nature of biopsies in such patients, CT has an important role for the diagnosis of this condition.     

Effects of Some Metals and Chelating Agents on Patulin Degradation by Ozone

The efficiency of ozone treatment for degradation of the mycotoxin patulin in the presence of various metal ions was evaluated in model systems. An initial patulin concentration of 250 μg/L was ozonated and residual ozone concentration was about 0.17±0.01 mg/L at the end of the experiment. Patulin showed a weak resistance to ozone, because up to 98% of this toxin was oxidized in only one minute. Degradation rates in the presence of calcium, aluminum, copper and zinc were almost the same in the absence of these metals. However, degradation of patulin was reduced from 98 to 37% when the concentration of manganese increased from 0 to 3 mg/L. Patulin was almost completely degraded in the absence of iron, while the degradation was only 8.5% in the presence of 0.5 mg/L of iron. These results have revealed that manganese and iron significantly reduce the detoxification of patulin by ozone. Agents such as ethylenediaminetetraacetic acid and sodium polyphosphate effectively chelated iron and increased the degradation rate of patulin. None of the tested agents were able to chelate manganese and to enhance patulin degradation by ozone.