Modern emerged technologies impose development and fabrication of miniatur-ized parts and devices in the micro- and nano-scale. Producing micro- and nano-featured structures requires nonconventional machining processes where con-ventional machining processes such as grinding, milling and eroding have failed. New emerging processes, such laser machining processes, are still fraught with almost invincible processes. Micro-/nano-machining are the pro-cesses of producing parts, microsystems or features at a scale of a few microm-eters and less than one hundred nanometers, respectively. Precise cutting and clean material removal accompanied with a negligible heat affected zone (HAZ), which are usually the characteristics of laser ablation, have opened a wide door for the evolution of remarkable technologies. This has been demonstrated by applications in different fields such as medicine, biotechnology, materials pro-cessing, microelectromechanical systems, electronics and communications. The continuous development in laser technology in terms of ultra-short pulse width, short wavelength and optics technologies has reduced the drawbacks of diffrac-tion-limited processing accuracies. Laser micro-/nano-machining requires the attainment of high fluence and short interaction time to achieve ablation pro-cesses in nanofabrication and structuring of different materials. To conduct the optimum desired machining process, it is important to integrally consider a number of laser beam and working parameters. Laser wavelength, beam mode, minimum attainable spot size, peak power, pulse duration, pulse repetition rate and scanning speed are some of the important considerations. Manipulating those parameters is crucial for ideal laser ablation represented by yielding the highest resolution of machining with the least lateral dimensions, acceptable depth and minimal or no melt at the edges. The assembly of laser beam delivery and focusing system with an automation system are the essential factors for workpiece positioning and obtaining the desired dimensions. The objective of this chapter is to review the effective parameters associated with laser machin-ing processes that affect the dimensions and quality of laser machining at the micro-/nano-scales in a simple presentation. The review is supported by demonstrating laser processing techniques applied in the field of micro-/nano-machining such as mask, interferometric and scribing techniques.
In the present work, a d.c. magnetron sputtering system was designed and fabricated. The chamber of this system was includes from two copper coaxial cylinders where the inner one used as a cathode (target) while the outer one used as the anode with Solenoid magnetic coil located on the outer cylinder (anode). The axial profile of magnetic field for various coil current (from 2A to 14 A) are shown. The plasma characteristics in the normal glow discharge region are diagnostics by the 2.2mm diameter Langmuir probe with different length along the cathode and located at different radial positions 1cm and 2cm from the cathode surface. The result of this work shows that, the electron energy distributions at different radial positions along the
... Show MoreMany organizations today are interesting to implementing lean manufacturing principles that should enable them to eliminating the wastes to reducing a manufacturing lead time. This paper concentrates on increasing the competitive level of the company in globalization markets and improving of the productivity by reducing the manufacturing lead time. This will be by using the main tool of lean manufacturing which is value stream mapping (VSM) to identifying all the activities of manufacturing process (value and non-value added activities) to reducing elimination of wastes (non-value added activities) by converting a manufacturing system to pull instead of push by applying some of pull system strategies a
... Show MoreBackground: breast cancer is commonest cancer globally and the 1st cancer in Iraq among females, its management and prognosis depend on early diagnosis, the traditional method was excisional biopsy which is expensive and invasive leading to delayed diagnosis, FNAB is cheap nom invasive more acceptable to women, Aim of the study: to test the reliability of FNAB in preoperative diagnosis of breast lump.
Methodology: This is a retrospective study of 204 cases, 102 breast cancer cases and 102 benign breast lesions, taken between Jan. 2017 – Nov. 2017. The sample taken from the breast cancer early detection center in Al-Alwiyaa maternity teaching hospital, during the year 2017
... Show MoreChemical analysis for evaluation of Nigella sativa L. (black cumin) seeds showed a composition of Fat 39% ; Protein 28% ; Carbohydrate 21% ; Moisture 6% and Ash 4.5% . It was found that the black seed contains the following mineral element : Magnesium 0.26 gm /100gm seed ; Calcium 0.25 gm /100gm seed and Iron 25 ?g / gm /100gm seed ; zinc 4.51?g /gm /100gm seed and Copper 3.60 ?g /gm /100gm seed. The analysis also showed that mineral element I. e. ; lead ; Cobalt ; Nickel ; Chrom ; Cadmium and Aresenic are not present . It was found that the fat of the black seed contains the following fatty acids : Myristic 2.8%; Palmtic 16.6%; Stearic 0.8 % ; Oleic 13.79% ; Linoleic 64.2% and Arachidic 1.9% .
The present study was conducted to determine the effect of Manganese on Histopathological changes in testes. Manganese Chloride was given to white mice with oral containing 150_200 and 250 mg/kg for periods of 15_30 and 45 days. The present study recorded the existence of histopathological symptoms in the testes, such as degeneration and necrosis in the tubules, congestion inside blood vessels and Edema in the interstitial tissue, as well as the appearance of giant cells inside the seminiferous tubules.
Background: Chronic periodontitis defined as “an infectious inflammatory disease within supporting tissues of the teeth, progressive attachment loss and bone loss". Aggressive periodontitis is rare which in most cases manifest themselves clinically during youth. It characterized by rapid rate of disease progression .Pro-inflammatory chemokines organized inflammatory responses. Granulocyte chemotactic protein 2 is involved in neutrophil gathering and movement. The purpose of the study is to detect serum of Granulocyte Chemotactic Protein 2 and correlate to periodontal condition in patients with chronic periodontitis, Aggressive periodontitis and Healthy Control subjects and measurement the count of neutrophils for the studied groups. S
... Show MoreIn the last decades of the twentieth century, ideas emerged that were increasingly being floated, stating that the planet is suffering from a population explosion, depletion of resources, and environmental problems that require action to be addressed. Although these problems in practice need scientific solutions, the problem is that these solutions collide with ideologies. Here the green political thought emerges, based on the criticism of many ideological axioms. The owners of green thinking agree that most environmental damage is due to the humanist doctrine. It criticizes modernity accompanied by a scientific revolution, where this criticism centered around (the rationality of the scientific and technological mind), here the green pol
... Show MoreKinetic and mechanism studies of the oxidation of oxalic acid by Cerium sulphate have been carried out in acid medium sulphuric acid. The uv- vis. Spectrophotometric technique was used to follow up the reaction and the selected wavelength to be followed was 320 nm. The kinetic study showed that the order of reaction is first order in Ce(IV) and fractional in oxalic acid. The effect of using different concentration of sulphuric acid on the rate of the reaction has been studied a and it was found that the rate decreased with increasing the acid concentration. Classical organic tests was used to identify the product of the oxidation reaction, the product was just bubbles of CO2.