Stereo lithography (SLA) three-dimensional (3D) printing process is a type of additive manufacturing techniques that uses digital models from computer-aided design to automatically produce customized 3D objects. Around 30 years, it has been widely utilized in the manufacturing, design, engineering, industrial sectors and its applications in dentistry for manufacturing prosthodontics are very important. The stereo lithography technology is highly regarded because it can produce items with excellent precision especially when selecting the best process parameters. This review article offers a useful and scientific summary of SLA three-dimensional printing technology and its brief history. The specific type of 3D printers which is SLA type based on light curing resin and material overview is also presented. Moreover, the survey was conducted to gain substantial knowledge of the various advantages and disadvantages of SLA 3D printing. According to this study, a summary has been specified on the accuracy of SLA 3D printers and various factors that affected its accuracy and dimension measurement namely layer thickness, normal exposure time, bottom or top exposure time, post processing and room temperature. The majority of works in the literatures conducted till date are on improving the physical part attributes like dimensional accuracy and surface roughness but the improving of the mechanical properties have received less attention and need more focusing in the future works.
Polymer electrolytes were prepared using the solution cast technology. Under some conditions, the electrolyte content of polymers was analyzed in constant percent of PVA/PVP (50:50), ethylene carbonate (EC), and propylene carbonate (PC) (1:1) with different proportions of potassium iodide (KI) (10, 20, 30, 40, 50 wt%) and iodine (I2) = 10 wt% of salt. Fourier Transmission Infrared (FTIR) studies confirmed the complex formation of polymer blends. Electrical conductivity was calculated with an impedance analyzer in the frequency range 50 Hz–1MHz and in the temperature range 293–343 K. The highest electrical conductivity value of 5.3 × 10-3 (S/cm) was observed for electrolytes with 50 wt% KI concentration at room
... Show MoreContinuous conflict between Parisian and Ottoman states the results that Iraq became as
aground for their battles which leads to their own interests in Iraq which are shape their
strategy. The conflict continues for long time. In spite of, they signed many treatments and
protocols between the two sides, as Arzarom treaty , the first and the second, Tahran protocols
, and Astana protocol. This conflict, no sides of them to dose any part of their land, but these
treaties leaded to a big loss to Iraq ,which lost parts of it's land and water area in Ahwaz and
shatt AL-Arab, so, Iraq became as a smoth target for their interests, and lost its
sovereignty,and lost self-govern of the country country . so the research conclud
The study consists of video clips of all cars parked in the selected area. The studied camera height is1.5 m, and the video clips are 18video clips. Images are extracted from the video clip to be used for training data for the cascade method. Cascade classification is used to detect license plates after the training step. Viola-jones algorithm was applied to the output of the cascade data for camera height (1.5m). The accuracy was calculated for all data with different weather conditions and local time recoding in two ways. The first used the detection of the car plate based on the video clip, and the accuracy was 100%. The second is using the clipped images stored in the positive file, based on the training file (XML file), where the ac
... Show MoreThe current study is an attempt to assess the cytogenotoxic potential of the ethanolic extract from the leaves of Borago officinalis on Swiss albino male mice. Young Swiss albino mice were orally administered with leaf ethanolic extract of Borago officinalis. Three mice groups were used using different doses of plant extract (T1: 100, T2: 200, and T3:400 mg\kg) in addition to the control negative group (untreated mice) for 7 days to assess mitotic index or 28 days to assess meiotic index. The results revealed that the extract significantly induced the division of disruptive chromosomal changes in the bone marrow and the mean of abnormality was (3.5±0.47, 4.43±0.83, and 5.83±0.96%) for T1, T2, and T3 re
... Show MoreData steganography is a technique used to hide data, secret message, within another data, cover carrier. It is considered as a part of information security. Audio steganography is a type of data steganography, where the secret message is hidden in audio carrier. This paper proposes an efficient audio steganography method that uses LSB technique. The proposed method enhances steganography performance by exploiting all carrier samples and balancing between hiding capacity and distortion ratio. It suggests an adaptive number of hiding bits for each audio sample depending on the secret message size, the cover carrier size, and the signal to noise ratio (SNR). Comparison results show that the proposed method outperforms state of the art methods
... Show MoreChacha 20 is a stream cypher that is used as lightweight on many CPUs that do not have dedicated AES instructions. As stated by Google, that is the reason why they use it on many devices, such as mobile devices, for authentication in TLS protocol. This paper proposes an improvement of chaha20 stream cypher algorithm based on tent and Chebyshev functions (IChacha20). The main objectives of the proposed IChacha20 algorithm are increasing security layer, designing a robust structure of the IChacha20 to be enabled to resist various types of attacks, implementing the proposed algorithm for encryption of colour images, and transiting it in a secure manner. The test results proved that the MSE, PSNR, UQI and NCC metrics
... Show MoreIn this paper, we study the incorporation of the commensalism interaction and harvesting on the Lotka–Volterra food chain model. The system provides one commensal prey, one harvested prey, and two predators. A set of preliminary results in local bifurcation analysis around each equilibrium point for the proposed model is discussed, such as saddle-node, transcritical and pitchfork. Some numerical analysis to confirm the accruing of local bifurcation is illustrated. To back up the conclusions of the mathematical study, a numerical simulation of the model is carried out with the help of the MATLAB program. It can be concluded that the system's coexistence can be achieved as long as the harvesting rate on the second prey population is
... Show MoreIn this paper, CdO nanoparticles prepared by pulsed laser deposition techniqueonto a porous silicon (PS) surface prepared by electrochemical etching of p-type silicon wafer with resistivity (1.5-4Ω.cm) in hydrofluoric (HF) acid of 20% concentration. Current density (15 mA/cm2) and etching times (20min). The films were characterized by the measurement of AFM, FTIR spectroscopy and electrical properties.
Atomic Force microscopy confirms the nanometric size.Chemical components during the electrochemical etching show on surface of PSchanges take place in the spectrum of CdO deposited PS when compared to as-anodized PS.
The electrical properties of prepared PS; namely current density-voltage charact
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The public procurement crisis in Iraq plays a fundamental role in the delay in the implementation of construction projects at different stages of project bidding (pre, during, and after). The procurement system of any country plays an important role in economic growth and revival. The paper aims to use the fuzzy logic inference model to predict the impact of the public procurement crisis (relative importance index and Likert scale) was carried out at the beginning to determine the most important parameters that affect construction projects, the fuzzy analytical hierarchy process (FAHP) to set up, and finally, the fuzzy decision maker's (FDM) verification of the parameter for comparison with reality. Sixty-five
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