Electrical and optical properties of fluorine-doped CdO films deposited by ultrasonic spray pyrolysis

The CdO:F samples have been deposited onto microscope glass substrates at 250 °C by ultrasonic spray pyrolysis method. With the incorporation of fluorine into CdO, the direct optical transition has shifted towards the shorter wavelengths, and the transparency of the material has increased at a given wavelength above the fundamental absorption edge. The shift in the absorption edge is explained by means of the Moss–Burstein effect, which is also supported with the results of the current–voltage characteristics. Here, a correlation has been established between the band broadening and the increase in conductivity due to the increase in carrier density.     

Swenson's operation for neonatal Hirschsprung's disease

OBJECTIVE: To describe our experience with Swenson's operation for Hirschsprung's disease done during the neonatal period. DESIGN: Retrospective study. SETTING: University department of paediatric surgery. SUBJECTS: 10 Neonates with Hirschsprung's disease. INTERVENTIONS: Rectosigmoidectomy and pull through (Swenson's operation), with covering transverse colostomy. MAIN OUTCOME MEASURES: Mortality, morbidity, and continence. RESULTS: The median age at definitive operation was 25 days (range 15-35). There was one late death three weeks after discharge from hospital of respiratory and cardiac failure. Two patients presented with caecal perforation and two with intestinal obstruction; in all four Hirschsprung's disease was diagnosed on frozen section, a transverse colostomy was done, and the Swenson's operation was done electively. The other six were diagnosed by barium enema examination and biopsy, and underwent total bowel irrigation followed by Swenson's operation and transverse colostomy. The colostomies were closed three to four weeks later. There were no postoperative complications. All nine surviving patients were continent (3-4 stools/day), at a mean (SD) follow up of 21 (5) months. CONCLUSION: With the current high standards of anaesthesia and neonatal intensive care, and an experienced surgeon, Swenson's operation for neonatal Hirschsprung's disease is safe and the procedure of choice for this condition.     

Improvement of flexural bond strength of zirconia-resin cement by surface patterning using sub-nanosecond UV laser

Zirconia is a dental material that shows excellent biocompatibility and high strength in clinical applications. This study aims to evaluate the effects of ultrafast laser applications. The surface nanostructures were classified into three groups. Group 1 was generated using the burst mode, with three different distances between dots: 52 µm (Group 1a), 104 µm (Group 1b), and 156 µm (Group 1c). Group 2 was processed using the scanning mode configuration, with a set of parallel lines. Group 3 was also processed using this scanning configuration creating a set of square-shaped patterning. Group 4 was the control group. After the surface treatments, a pair of zirconia specimens was bonded end to end with resin cement. Flexural bond strength (FBS) test was applied in a universal test machine. Multiple comparisons were performed using a one-way analysis of variance and the Tukey's HSD test. All the samples that were treated with the laser showed higher FBS values than the untreated surface. Using the burst mode, preformed circular-shaped surface on an angle of 90⁰ at 52 µm distance (Group 1a) showed the highest FBS values among all groups (p < .05). Groups 2 and 3 had significantly higher values than 1b and 1c.     

Leaching of a copper flotation concentrate with ammonium persulfate in an autoclave system

The leaching behavior of a copper flotation concentrate was investigated using ammonium persulfate （APS） in an autoclave systee. The decomposition products of APS, active oxygen, and acidic medium were used to extract metals from the concentrate. Leaching experiments were performed to compare the availability of APS as an oxidizing agent for leaching of the concentrate under atmospheric conditions and in an autoclave system. Leaching temperature and APS concentration were found to be important parameters in both leaching systems. Atmospheric leaching studies showed that the metal extractions increased with the increase in APS concentration and temperature （up to 333 K）. A similar tendency was determined in the autoclave studies up to 423 K. It was also determined that the metal extractions decreased at temperatures above 423 K due to the passivation of the particle surface by molten elemental sulfur. The results showed that higher copper extractions could be achieved using an autoclave system.     

On the design considerations of solid-state power amplifiers for satellite communications: A systems perspective

Conventional solid-state power amplifier (SSPA) design approach isolates radio frequency (RF) design from communication theory. In this paper, a unified SSPA design approach is proposed, which optimizes SSPA parameters (bias voltage and input RF signal power) to minimize total DC power consumption while satisfying received SNR constraint specified by the link budget. The effect of SSPA nonlinearity is quantified by the error vector magnitude measured at its output and the corresponding received SNR degradation is analyzed. Using the quantitative metrics for received SNR, it is possible to evaluate highly nonlinear SSPA classes such as Class-B or deep-Class AB, which are normally not considered in conventional SSPA design approach to be used in satellite communication applications.     

Thermocapillary Flow and Coalescences of Heterogeneous Bubble Size Diameter in a Rotating Cylinder: 3D Study

Two dimensional axisymmetric and three-dimensional VOF simulations of gas/liquid transient flow were performed using a multiphase flow algorithm based on the finite-volume method. The results for motion of a multiple bubbles of a heterogeneous sizes aligned horizontally and perpendicular to a hot surface incorporating thermocapillary forces in a rotating liquid in a zero-gravity environment have been presented for the first time. No bubbles broke in any of the cases observed. The results also show that collision and agglomeration of bubbles of unequal sizes diameter are different from those of similar size diameters presented from earlier research work of Alhendal et al. Acta Astronaut. 117, 484–496 (2015). Different flow patterns such as thermocapillary bubble migration, collision, and stream function were observed and presented for the 2-D and 3-D models.     

Adaptive popularity-driven replica placement in hierarchical data grids

Data grids support access to widely distributed storage for large numbers of users accessing potentially many large files. Efficient access is hindered by the high latency of the Internet. To improve access time, replication at nearby sites may be used. Replication also provides high availability, decreased bandwidth use, enhanced fault tolerance, and improved scalability. Resource availability, network latency, and user requests in a grid environment may vary with time. Any replica placement strategy must be able to adapt to such dynamic behavior. In this paper, we describe a new dynamic replica placement algorithm, Popularity Based Replica Placement (PBRP), for hierarchical data grids which is guided by file “popularity”. Our goal is to place replicas close to clients to reduce data access time while still using network and storage resources efficiently. The effectiveness of PBRP depends on the selection of a threshold value related to file popularity. We also present Adaptive-PBRP (APBRP) that determines this threshold dynamically based on data request arrival rates. We evaluate both algorithms using simulation. Results for a range of data access patterns show that our algorithms can shorten job execution time significantly and reduce bandwidth consumption compared to other dynamic replication methods.     

Online tax payment systems as an emergent aspect of governmental transformation

The achievement of governmental transformation through the use of electronically delivered services is a worthy goal that requires significant planning and research to achieve. In order to reach transformational paradigm shifts in governmental operation, it will first be necessary to understand and optimize present governmental e-Service provisions. Of these, the revenue function of taxation is paramount. This paper describes factors related to the use and acceptance by accounting professionals of information technology intended to facilitate electronic tax filing systems. Though tested in the context of governmental tax management systems in Turkey, our findings on the use and acceptance of e-Tax systems are relevant and applicable to a great number of nations and contexts as the ongoing electronic transformation of the governmental revenue system contributes to efforts to transform governments through alternative services delivery venues and channels. We discover that intention to use automated systems as part of the governmental treasury function transformation is hindered by factors that mediate actual plans to do so, mostly in terms of normative pressures and perceptions of behavioral control, which training and education may well ameliorate. Hence, transformation of the treasury function in Turkey is only partially complete and will require additional support, direction and training on the part of the government in its interactions with the tax professionals who interact with the emergent automated system.     

An Analytical Approach to the Concept of Counter-UA Operations (CUAOPS)

Unmanned Aircraft (UA) have become an integral part of the present-day joint air operations. UA have potential to be employed across the full spectrum of Air Force functions. On the other hand, UA technology could be a subject of an asymmetric use by state actors in high or low density conflict, and/or by non-state actors in many ways including terrorism, drug smuggling, and limited attack with unconventional payloads i.e. biological or chemical agents. Therefore countering the threat associated with the hostile UA use could be necessary in the future. First part of the research revealed that UA can be a threat in the future. In the second part of the research, the SWOT (Strengths-Weaknesses-Opportunities-Threats) analysis supplemented with the Tree analysis (SWOT+Tree) provided a broader look for investigating the factors related to hostile UA use analytically. In literature, there is little information about the concepts for CUAOPS. The final goal of the paper is to find possible solutions and means for a better understanding of the nature of CUAOPS.     

High-Modulus Columns for Liquefaction Mitigation

This paper presents the performance of a shopping complex in Turkey where the soils were improved with jet-grout columns and preload fills and subjected to the 1999 Kocaeli Earthquake (M = 7.4). Under construction at the time of the earthquake, the Carrefour Shopping Center covers an area of 55,000?m2 and is founded on shallow footings, mats, and slabs-on-grade that rest on soft, saturated alluvial sediments consisting of clays, silts, and sands. High-modulus columns constructed by jet grouting were installed at close-to-moderate spacings to reduce anticipated static settlements in the clays and mitigate liquefaction in the sands. The site was subjected to a peak acceleration of approximately 0.2g during the earthquake. Grouting had been completed for about two-thirds of the site when the earthquake struck. Following the event, a field reconnaissance found stark contrast between the performance of the improved and unimproved sections. The jet-grout-treated areas suffered no apparent damage, whereas the unimproved sections of the complex, along with nearby untreated building sites, commonly suffered liquefaction-related settlements of up to 10 cm. This is the only case history known to the authors that documents the field performance of high-modulus columns used in this manner for liquefaction mitigation and direct instrumented measurement of liquefaction-induced settlements.