Showing papers by "Military Academy published in 2009"

Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

Abstract: In this study, effects of oxygen pressure in the sputtering ambient on the preferential orientation and resultant surface morphology of ITO films grown by RF magnetron sputtering were investigated. ITO film grown with pure Ar gas shows a preferential (400) plane orientation parallel to the substrate surface and a sawteeth-shaped rough surface. ITO film grown in the sputtering ambient of Ar and oxygen mixtures shows a preferential (222) plane orientation and a flat and smooth surface. The differences in the growth rate, surface morphology, and roughness between the preferentially orientated films were discussed in terms of the surface energy of planes. The electrical and optical properties of the films were examined.

A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme

Abstract: This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD). In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5° error.

Simvastatin and Indomethacin Have Similar Anti‐Inflammatory Activity in a Rat Model of Acute Local Inflammation

Abstract: Statins, such as simvastatin, lower circulating cholesterol levels and are widely prescribed for the treatment of hypercholesterolaemia. Several studies have shown unexpected effects of statins on inflammation. We studied the anti-inflammatory effect of simvastatin using a standard model of an acute local inflammation, the carrageenan-induced footpad oedema. Experimental groups (n = 6-8) were given simvastatin in a dose range 5-30 mg/kg, indomethacin 1-8 mg/kg and methylcellulose (control) per os. Footpad volume was measured with a plethysmograph and compared with the pre-injection volume of the same paw. Swelling (in microlitres) was then calculated, and in drug-treated animals, per cent inhibition was derived through comparison with the control group. Histopathological examination of the skin biopsies was performed to examine severity of paw skin lesions and to confirm the simvastatin-induced inhibition of acute inflammation. Both simvastatin and indomethacin administered orally, 1 hr before carrageenan injection, significantly reduced the extent of footpad oedema. Indomethacin dose-dependently blocked the swelling; the maximal effect was obtained with 8 mg/kg by 48.3% (P < 0.05). Simvastatin produced a comparable anti-inflammatory activity at a dose of 5 mg/kg (32%), while 10 and 30 mg/kg caused a 47.6% and 51.7% reduction, respectively, with the maximal effect observed at 20 mg/kg by 57.2% (P < 0.05). The comparison of the ED(50) of these agents on molar basis showed equipotent anti-inflammatory activity. Histopathological examination of the footpad skin biopsies revealed that simvastatin, dose-dependently and comparablly to indomethacin, reduced polymorphonuclear leucocyte infiltration. These data support the hypothesis that simvastatin has an acute anti-inflammatory activity.

Salvaging the zone of stasis by simvastatin: an experimental study in rats

Abstract: Salvaging the zone of stasis is important for burn researchers because this can prevent an increase in the depth and width of the injured area. Statin analogues have many pleiotropic effects on the vessel walls and the coagulation and fibrinolytic systems. In this study, we investigated the effects of simvastatin, a statin analogue, administered to rats burned with a metal comb. No treatment was given to the control group (n = 10). Simvastatin was given at a dose of 5 mg/kg/d by intraperitoneal injection in treatment group (n = 10) for 7 days. Phosphate-buffered saline was given 1 mg/kg/d by intraperitoneal injection in sham group (n = 10). The groups were randomly divided into two subgroups (n = 5) for evaluation at 24 hours and 7 days. It was observed that there were necrotic areas and viable interspaces in both the experimental and control groups at 24 hours. The interspaces progressed to necrotic areas in the control and sham groups at 7 days. However, viable interspaces were separated from necrotic areas clearly in the treatment group at 7 days. In the samples taken from interspaces at 24 hours, positive staining for thrombomodulin (TM) for all groups was noted. In the samples taken from the control and phosphate-buffered saline groups at 7 days, there was negative staining for TM. However, in the samples taken from interspaces of the treatment group, positive staining for TM was observed. The conclusion of this study was that simvastatin potently increased endothelial TM expression in the zone of stasis and preserved the zone.

Unusual clinicopathological presentation of primary cutaneous diffuse large B-cell lymphoma, leg type, with multiple nodules and widespread garland-like lesions.

Abstract: We present a case of primary cutaneous diffuse large B-cell lymphoma, leg type, with an unusual clinical picture. A 41-year-old man presented with a 2-year history of slowly progressive plaques, nodules, and garland-like patches on his chest, right upper arm, and back. Complete staging investigations revealed no extracutaneous involvement. Histological examination of a nodule revealed a diffuse nonepidermotropic infiltrate mainly composed of large blast cells with features of immunoblasts and centroblasts and spindle cells seen at the periphery of the infiltrate. Histological examination of a garland-like lesion showed perivascular infiltrates composed predominantly of small lymphocytes admixed with only occasional large blasts. The blasts from the nodule and garland-like lesions and spindle cells identified in the nodule exhibited an identical phenotype: they stained positively for CD20, CD79a, and bcl-2 and tested negative for bcl-6, CD5, CD10, and TdT. CD35 revealed no networks of follicular dendritic cells. Widespread garland-like lesions are not a typical feature of primary cutaneous diffuse large B-cell lymphoma.

Method of planning construction projects, taking into account risk factors

Abstract: This paper presents an original method of planning construction projects, taking into account the influence of potential risk factors. The method is called the Method of Construction Risk Assessment (MOCRA). According to this method, first the material-financial plan of a project (a construction project in the example provided) is analyzed. Then risk factors are identified, taking into account the project’s specificity. The end result of this stage is a list of risk factors. In the third stage the risk is reduced or minimized where possible. Finally, the specified risk factors are quantified, which is a difficult task. The effectiveness of the risk assessment depends on how thoroughly this task is carried out. Since point scale assessment of risk does not appeal to engineers, in MOCRA quantified risk is allocated in the material-financial plan. Thanks to this, one can prepare contingency plans, i.e. plans (action variants) to be implemented when particular risk factors occur. Having completed the project, one can use MOCRA to check the accuracy of the assessment (forecast) and select the best contingency action variant, whereby the method’s effectiveness in planning future projects is improved.

Effect of Manganese Dioxide Dispersion on the Absorbing Properties of Manganese Dioxide (MnO2)-Epoxy Composites

Abstract: Manganese dioxide (MnO 2 ) particle was synthesized and introduced into epoxy resin to be microwave absorber. The spectroscopic characterization of the formation processes of MnO 2 was studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microwave absorbing properties with different volume fractions of Mn0 2 were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2-18 and 18-40 GHz microwave frequency range using the free space method. The absorbing performance of MnO 2 -epoxy composites at same sample thickness and at various sample thickness were also studied. It was found that the best absorbing property and an absorption frequency range shifting could be obtained at the frequency range of 2-18 and 18-40 GHz.

Determination of the Chain-Like Non-Linear Multi-Degree-of-Freedom Systems Constant Parameters under Dynamical Complex Loads

Abstract: Institute of Materials Science and Applied Mechanics, Wroclaw University of Technology, Smoluchowskiego 25, 50-370 Wroclaw, Poland A determination of mechanical properties of the real material systems under dynamical excitations is a very complex problem. The real system can be described by continuous model as well as a discrete model with a finite number of degree-of-freedom. Some mechanical systems like beams, rods, strings, tow-lines etc. have so-called chain-like configuration and may be treated as the dynamical one-dimensional cascade systems. In this paper, an identification method of internal interaction force, which can be arbitrary selected in discrete chain-like non-linear system, is presented. The method was tested on example of a two-mass system in which the interaction forces were modeled by spring-damper elements in a non-parallel arrangement. In experiment some non-sinusoidal complex loads were applied.

Long range standoff detection of chemical and explosive hazards on surfaces

Abstract: Fielded surface detection systems rely on contact with either the liquid contamination itself or the associated chemical vapor above the contaminated surface and do not provide a standoff or remote detection capability. Conversely, standoff chemical vapor sensing techniques have not shown efficacy in detecting those contaminants as liquids or solids on surfaces. There are a number of optical or spectroscopic techniques that could be applied to this problem of standoff chemical detection on surfaces. The three techniques that have received the most interest and development are laser induced breakdown spectroscopy (LIBS), fluorescence, and Raman spectroscopy. Details will be presented on the development of these techniques and their applicability to detecting CBRNE contamination on surfaces.

Hybrid laser—magnetron technology for carbon composite coating

Abstract: Hybrid laser- magnetron deposition system was developed and tested for study of carbon based thin film coatings. Various geometrical configurations and deposition conditions were tested. Films of TiC, TiCN, and SiC were synthesized. Films were fabricated in argon (TiC), in argon/nitrogen (TiCN), or in argon/hydrogen ambient (SiC films). Film properties were studied by SEM, XRD, GDOES, and XPS. Smooth, homogeneous film over the area of 9 cm2 were prepared. Crystalline TiC films were grown at room substrate temperature.

The thermal conductivity of alumina thin film for LED

Abstract: Thermal management has the important influence in quantum effect of light emitting diodes (LED) based on printed circuit board (PCB). In the industrial processing, the quality of the thermal dissipation is decided by the gumming technique between the PCB and aluminum plate. Because it transfers the heat from electric device to the aluminum plate, which completely removes the heat. In this study, a superior method, alumina thin films, soldered the LED lamps to enhance the heat transfer. The films were fabricated onto 1070 aluminum alloy substrate by plasma spraying, vacuum sputtering and electric plating technologies. The dielectric coatings were characterized by several subsequent analyses, especially the measurement of thermal resistance. The X-Ray diffraction (XRD) diagram analysis reveals that alumina phases were successfully grown on the individual substrate. Compared to alumina coating fabricated by plasma spraying and electric plating technologies, vacuum sputtering creates low sheet resistivity, high hardness, high critical load, and good thermal conduction of 119 W/m-K.

Development of radioresistance in drug resistant human MCF-7 breast cancer cells

Abstract: Background and purpose: Radiotherapy is used for the treatment of malignant tumours, and may be used as the primary therapy. It is also common to combine radiotherapy with surgery, chemotherapy, hormone therapy or some combination of them. Even if the tumour is treated intensively, women diagnosed with breast cancer may develop a recurrence. Most recurrences may be in the form of distant metastases, development of multi-drug resistance phenotype or both together. This study demonstrated that some of the multi-drug resistant cancer cells may also become radioresistant.Materials and Methods: Chemoresistance in paclitaxel (MCF-7/Pac), docetaxel (MCF-7/Doc), vincristine (MCF-7/Vinc), doxorubicin (MCF-7/Dox) and zoledronic acid (MCF-7/Zol) resistant MCF-7 cells were demonstrated by XTT assay. MDR1 gene expression was detected by real-time PCR in human MCF-7 breast cancer cells. Drug resistant and sensitive cells were exposed to γ-radiation and development of radioresistance was investigated.Results: Results have indicated that paclitaxel, docetaxel, vincristine, doxorubicin and zoledronic acid–selected cells gained varying degrees of resistance to their selective drugs when compared with original MCF-7/S. MCF-7/Pac, MCF-7/Doc, MCF-7/Vinc and MCF-7/Dox cells have all acquired MDR1 expression. Among the resistant sub-lines, MCF-7/Pac and MCF-7/Doc cells were significantly cross-resistant to irradiation compared to the sensitive cells.Conclusion: MCF-7/Pac and MCF-7/Doc cell lines were found radioresistant to γ-radiation. On the contrary, doxorubicin, vincristine and zoledronic acid resistant cancer cells were still sensitive to radiation.

Preparation and Antibacterial Effect of Bamboo Charcoal/Ag on Staphylococcus Aureus and Pseudomonas Aeruginosa

Abstract: Bamboo charcoal supporting silver (BC/Ag) was prepared by activation and chemical reduction. The BC/Ag composites were characterized by silver particle size and distribution, silver ion (Ag + ) release and antibacterial properties. Scanning and transmission electron microscopy (SEM and TEM) showed that the Ag particles were distributed uniformly on the BC matrix. The Ag particle size was found to be less than 150 nm based on TEM. The Ag + release increased initially which was followed by a marginal increase between the 8th and 24th hour. Composites contained higher amounts of silver exhibited a further rise in Ag + release from the 24-hours of storage in water. The antibacterial effects of the BC/Ag composite powders against Pseudomonas aeruginosa and Staphylococcus aureus were assessed from the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) method, and an excellent antibacterial performance was discovered.

MRI evaluation of the classification, frequency, and disc morphology of temporomandibular joint disc displacements: a multicenter retrospective study in a Turkish population

Abstract: Objectives Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) and temporomandibular disorders (TMDs) have been discussed in detail for various populations. As no such study has examined the Turkish population, we determined the frequency of TMDs in the Turkish population through a multicentric investigation using MRI.

Comparison of algorithms for the classification of polarimetric SAR data

Abstract: Most of the current SAR systems aquire fully polarimetric data where the obtained scattering information can be represented by various coherent and incoherent parameters. In previous contributions we reviewed these parameters in terms of their "utility" for landcover classification, here, we investigate their impact on several classification algoritms. Three classifiers: the minimum-distance classifier, a multi-layer perceptron (MLP) and one based on logistic regression (LR) were applied on an L-Band scene acquired by the E-SAR sensor. MLP and LR were chosen because they are robust w.r.t. the data statistics. An interesting result is that MLP gives better results on the coherent parameters while LR gives better results on the incoherent parameters.

Comparison of AF and DF relaying for uplink CDMA communications subject to constant multiple access interference cost

Abstract: In radio mobile cellular networks, the users located at the cell border suffer from a bad quality of service (QoS). Cooperative communication is a promising technique that can overcome this weakness by allowing these users to profit from powerful benefits of spatial diversity. Nevertheless, abstraction is usually made on the impact of the additional multiple access interference inherent to relaying. In a previous work, we have optimized amplify-and-forward (AF) relaying scheme subject to a constant multiple access interference cost for CDMA (Code Division Multiple Access) uplink communications. Here, we extend this work by dealing with performance optimization for decode-and-forward (DF) relaying subject to the same cost constraint for the same framework. We compare the performance of both optimized AF and DF schemes for different scenarii. A variety of simulation results reveals that DF relaying provides cellular performance enhancement in terms of BER (Bit Error Rate) over both direct transmission and AF relaying schemes.

The relationship between cyclic stress–strain curve and dislocation structures in cyclically deformed IF steel

Abstract: The cyclic stress–strain curve (CSSC) of cyclically deformed polycrystalline interstitial-free steels (IF steel), divided into regions A, B and C, have been correlated with the fatigue test conditions. No dislocation arrangement can be found when plastic strain amplitude is controlled in region A. For region B as revealed as a plateau, the plastic strain amplitude is located in the range between ɛ pl = 7.5 × 10 −5 (Δ ɛ /2 = 0.05%) and ɛ pl = 5 × 10 −4 (Δ ɛ /2 = 0.1%). Loop patches prevail in region B. If the strain amplitude is close to the upper limit of the region B, the loop-patch structure is also predominant in the dislocation structures despite the existence of dislocation walls and a few dislocation cells larger than 2 μm. However, these structures have no significant effect on fatigue failure. The dislocation cells rapidly developed once the plastic strain amplitude is elevated into region C.