Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF) acid, many questions remain unresolved, including the optimal ...etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.
This study was conducted in one of a diverse industrial area in Al-Akrasha, Egypt. Concentrations of select metals (Cu, Pb, Cr, Ni, Zn, Mn, Cd, Al, Ag, As, B, and Fe) were evaluated in ambient PM10 ...and surface soils at nine sites. Random samples of fresh edible tilapia fish were collected from Ismailia Canal at two sites near the Al-Akrasha region. In addition, blood and hair samples were collected from workers and residents living in Al-Akrasha as biomarkers of contamination with these metals. The ecological and health risks of these metals to the workers and residents living in the Al-Akrasha region were assessed. The results showed that heavy metal levels in the ambient air (PM10) of the Al-Akrasha region were higher than the national and international guidelines. There was a very high degree of contamination (CD > 32) of the surface soil in the Al-Akrasha area, which can be attributed to industrial activities emissions, mostly from smelters and the subsequent deposition on the surface soil. Ingestion was the dominant pathway for metals to enter the human body in the Al-Akrasha region. Adults have a higher daily intake and exposure risk than infants and children.
In this article, a novel millimeter wave (mm-wave), fully hermetic and flippable transitioning structure between grounded coplanar waveguides (GCPWs) and rectangular waveguides (RWGs) is introduced. ...This transition, realized through standard printed circuit board (PCB) technology, can be employed to feed a waveguide (WG) compliant device on any face of a board given its flexibility in trace routing and component placement. The proposed structure utilizes a mix of transmission line and substrate integrated waveguide (SIW) interconnected with an in-substrate embedded back-short. The transition, in all its configurations, targets a fractional bandwidth (FBW) wider than 20% to cover the commercial <inline-formula> <tex-math notation="LaTeX">E</tex-math> </inline-formula>-band spectrum. Moreover, at center frequency the predicted insertion loss (IL) for both normal and flipped transitions is 0.4 and 0.46 dB, respectively. Parametric and yield analyses, together with postmanufacturing inspections have been performed to assess the robustness of the design and to identify the critical manufacturing inaccuracies. The experimental validations confirm the wideband operation with an IL bounded below 2.3 dB for the worst case of a back-to-back configuration.
In this paper, the seismic performance of reinforced concrete exterior wide beam–column connections with shallow spandrel beams lightly reinforced for torsion and moderate levels of gravity loads was ...investigated experimentally. The study focuses on existing frames designed and detailed according to construction practices used over ten years ago in the moderate-seismicity Mediterranean area. The results can be useful for assessing the seismic vulnerability of older structures and orienting seismic retrofit alternatives. Two 3/5 scale test models representative of exterior sub-assemblages in a prototype six-story building were subjected to gravity-load levels typical of those acting during an earthquake, and quasi-static cyclic lateral loads until failure. The performance was studied in terms of strength, displacement, ductility and energy dissipation capacity. The data are analyzed in conjunction with the results of previous tests. The specimens exhibited a “strong column–weak beam” type of flexural yielding mechanism. The average drift ratios at first yielding of the wide beam longitudinal reinforcement,
δ
y
o
, and at failure,
δ
u
, were 2.2% and 4.5% respectively; the displacement ductility ratio
μ
was approximately 2.2. Comparison to similar connections without added gravity loads showed that moderate levels of gravity loading increased
δ
y
o
by about 40%, and decreased by a similar percentage the value of
μ
and the energy dissipated in each half cycle of displacement expressed in terms of an equivalent viscous damping ratio. Finally, two approaches for estimating the wide-beam flexural capacity are examined.
Here, a novel design of a planar monopole antenna is presented for wireless body area network (WBAN) wearable applications. The design is fabricated on flexible liquid crystalline polymer (LCP) ...substrate. The antenna is fed by a uni-planar coplanar waveguide transmission line and has total size of 51 × 22 mm2. In comparison with its recent published peers, the antenna has the thinnest thickness of 0.1 mm. The antenna is simulated and tested while physically bent. Proposed design along with simulation and experimental results are discussed in this work. Bottom rectangular slabs were added as a modification to the design in order to restore gain at higher frequencies. For the entire operational bandwidth, numerical far field simulations show the suitability of the proposed design to human body loading. A full study targeting specific absorption rate (SAR) has been performed to calculate the maximum input power to the proposed design. The objective has been to prevent any harm to human body as specified by the relevant international non-ionising radiation exposure standards.
A methodology for assessing the seismic capacity of existing frames in terms of energy is proposed. It estimates the global amount of input energy—in form of a factor
AE
IU
—and hysteretic energy ...that the overall structure can dissipate until collapse under earthquake-type loadings. The method requires static pushover analyses to determine the ductility factor and energy shape of an equivalent single-degree-of-freedom system for the first—two or more—modes. The procedure accounts for the relation between the frequency content of the earthquake expected at the site and the dynamic properties of the existing structure. It can be useful for evaluating the possible deficit on energy dissipation capacity of existing structures, and for designing seismic retrofit solutions. Finally, the methodology is applied to reinforced concrete frames with wide beam-column connections representative of existing post-1970 buildings located in the earthquake-prone southern part of Spain.
A high gain, low specific absorption rate, oval-shaped monopole antenna is presented. It is backed by an all-textile 3 × 3 array of electromagnetic bandgap (EBG) unit cells. The antenna is printed on ...the thin Rogers ULTRALAM 3850 substrate, while the EBG array is composed of the conductive ShieledIT Super and dielectric substrate felt. The design operates at 2.45 GHz of the Industrial, Scientific, and Medical band. Due to the close distance between the extended grounds of the co-planar waveguide feeding configuration and the oval-shaped monopole antenna, current-coupling was achieved, leading to gain enhancement. However, with body-loading cases, resonance at 2.45 GHz was attained at a separation of 30 mm. By incorporating the EBG array, as an isolator, this issue was resolved. In free space and over a gap of 3 mm from the human body, gain enhancements by 2.68 and 11.54 dB were achieved at 2.45 GHz, respectively. Simulated and measured results are benchmarked. Furthermore, SAR simulation study showed reductions by 99.5%, averaged over 1 and 10 g of tissue.
A multivariate extension of the adaptive exponentially weighted moving average (AEWMA) control chart is proposed. The new multivariate scheme can detect small and large shifts in the process mean ...vector effectively. The proposed scheme can be viewed as a smooth combination of a multivariate exponentially weighted moving average (MEWMA) chart and a Shewhart χ
2
-chart. The optimal design of the proposed chart is given according to a pre-specified in-control average run length and two shift sizes; a small and large shift each measured in terms of the non centrality parameter. The signal resistance of the newly proposed multivariate chart is also given. Comparisons among the new chart, the MEWMA chart, and the combined Shewhart-MEWMA (S-MEWMA) chart in terms of the standard and worst-case average run length profiles are presented. In addition, the three charts are compared with respect to their worst-case signal resistance values. The proposed chart gives somewhat better worst-case ARL and signal resistance values than the competing charts. It also gives better standard ARL performance especially for moderate and large shifts. The effectiveness of our proposed chart is illustrated through an example with simulated data set.
In this work, an <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> waveguide antenna array composed of stepped and slotted radiators for E-band applications is ...presented. The proposed array architecture, including the feeding network, can be realized through the integration of a single metallic block adhered with an additional top photo-etched sheet. This approach effectively reduces manufacturing complexity, resulting in a low-cost solution that can be easily fabricated using standard market-ready technologies. Array beam-forming network's building blocks: transitions, power dividers and <inline-formula> <tex-math notation="LaTeX">2\times 2 </tex-math></inline-formula> slotted splitters are presented. Parasitically coupled cavities, inserted in between slotted radiators, help to improve the matching and gain of the array. Stepped profile which has been applied to both active and parasitically coupled apertures, prove to enhance antenna parameters. The overall structure fills a volume of <inline-formula> <tex-math notation="LaTeX">25\times 24\times 2 </tex-math></inline-formula> mm 3. A 23.6% fractional bandwidth was achieved in the range of 69 - 86.7 GHz. Radiation characteristics were investigated for both <inline-formula> <tex-math notation="LaTeX">2\times 2 </tex-math></inline-formula> splitter radiators and <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> antenna arrays where the obtained average gain values were 12 and 25 dBi, respectively. A four-channel prototype was fabricated and measured. The measured radiation patterns agree with the simulated patterns, with a maximum aperture efficiency of 86%.
Multidimensional Almost Dominance Sayed, T. El; Zahran, A. R.
Social indicators research,
02/2018, Letnik:
136, Številka:
1
Journal Article
Recenzirano
A major drawback of First Order Stochastic Dominance approach is dominance indetermination. Levy and Leshno in 2002 suggested Almost Stochastic Dominance as a remedy in the uni-dimensional case. We ...introduce a Generalization of Almost First and second Order Dominance (MAFOD and MASOD) to the multidimensional case with application on child wellbeing in Egypt. We perform a multidimensional (FOD) analysis on seven deprivation indicators for three age-groups of children from Egypt 2014 Demographic and Health Survey (EDHS14). This methodology allows the ordinal ranking of regions and governorates of Egypt in terms of their children wellbeing based on their probability of domination. To solve the dominance indetermination we apply MAFOD and MASOD.
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