Optimization of pocket machining strategy in HSM

Our two major concerns, which should be taken into consideration as soon as we start the selecting the machining parameters, are the minimization of the machining time and the maintaining of the high-speed machining machine in good state. The manufacturing strategy is one of the parameters which practically influences the time of the different geometrical forms manufacturing, as well as the machine itself. In this article, we propose an optimization methodology of the machining strategy for pockets of complex forms. For doing this, we have developed analytic models expressing the feed rate of the cutting tools trajectory. Then, we have elaborated an optimization method based on the analysis of the different critical parameters so as to distinguish the most suitable strategies to calculate the cutting time and define the machine dynamics. To validate our results, we have compared them to the experimental ones and also to those found in literature

Calculations Of Stopping Power, And Range Of Electrons Interaction With Different Material And Human Body Parts

In this work we studied interaction electrons with matter; I calculated the stopping power (in MeV cm2/g) from the theory of Bethe-Bloch formula as giving in the reference, and the Range will be calculated. This has been done for different target materials in biological human body substances such as water, bone, muscle and tissue and different energies electrons. All these calculations were done using different programs; STAR and Matlab, the results will be shown for, stopping power vs energy and Range Vs energy. The stopping power in some biological compounds for electrons was calculated over the energy range from (10-2MeV to 103 MeV). Total stopping power was obtained by summing the electronic (collisional) and radiative stopping power of the target materials, and then employing the continuous slowing down approximation (CSDA) to calculate the path length (Range). The total stopping power is proportional to Z2, Z/A and I, increases rapidly at low energies, reaches a maximum and decreases gradually with increasing energy, the data were fitted to a suitable empirical formula as shown in the figures

Measurement of Radon Exhalation Rate from Destroyed Building Material in the Gaza Strip

Building materials are one of the potential sources of indoor radioactivity because of the naturally occurring radionuclides in them. Radon exhalation rate is one of the most important factors for evaluation of the environmental radon level. Radon contributes more than half of the total ionizing radiation dose Indoor radon has been recognized as one of the health hazards for mankind because long-term exposure to radon increases the risk of developing lung cancer. This study aims at assessing the contribution of destroyed building materials in war 2014 towards the total indoor radon exposure to the inhabitants of in Gaza. 40 Samples have been collected from common destroyed building materials in Jabalia district. The closed-can technique has been employed in this study using solid state nuclear track detectors (CR-39). After 124 days of exposure to radon, CR-39 detectors were etched chemically by (6 N) NaOH solution at 75C for three months and then counted under an optical microscope. Results obtained from the current study show that radon exhalation rates from concrete and asbestos have relatively high values as compared to other building materials while glass, marble and a red brick contribute less to radon exhalation rate. The average radon exhalation rate in term of area in the studied samples ranged from (86.506) mBq.m-2 .h-1 for glass samples to (469.017) mBq.m-2 .h-1 for Concrete samples. In general, the annual effective doses from the investigated building materials are low and under the global value (from 1 to 5 mSv/y) except for Concrete and asbestos samples with average values (9.464) and (9.3528) mSv/y, respectively

Pion double charge exchange formalism

The behavior of the operator responsible for sequential pion double charge exchange (DCX) on nuclei has been investigated in the plane wave limit in order to study its extension in space especially the short-range part. The DCX cross sections were calculated for Ca isotopes up to an incident pion energy of 300 MeV as two single-charge exchanges, using both the shell model and the seniority model. The effects of previously proposed modifications to the mechanism have been investigated at low energy, where a resonance-like structure in the energy dependence has been observed. One of the modifications that has been studied is the inclusion of pion true absorption in the pion optical potential, by extracting the coefficients which correspond to the calcium and carbon nuclei from existing data of pion absorption. The second effect studied is the removal of the delta function from the DCX amplitude (which originated from the idea of point-like pion-nucleon coupling), where the interaction extends over a finite region of space. This work was restricted to the sequential pion double charge exchange mechanism, which is generally believed to be dominant in many cases. These corrections have been studied in the plane wave and distorted wave modes. The results of these calculations for calcium agree with the data for the energies above 200 MeV and partially agree below 200 MeV. The calculations were done for different pion-nucleon ranges (a= 800, 600, 300 MeV/c). The DCX cross sections were calculated for ^'^C up to 300 MeV of pion energy using two single charge exchange (SCX) scattering steps on the valence nucleons and at different

Chaotic quantization and the mass spectrum of fermions

In order to understand the parameters of the standard model of electroweak and strong interactions, one needs to embed the standard model into some larger theory that accounts for the observed values. This means some additional sector is needed that fixes and stabilizes the values of the fundamental constants of nature. We describe how such a sector can be constructed using the so-called chaotic quantization method applied to a system of coupled map lattices. We restrict ourselves in this short note on verifying how our model correctly yields the numerical values of Yukawa and gravitational coupling constants of a collection of heavy and light fermions using a simple principle, the local minimization of vacuum energy.Comment: 8 pages, 6 figures. To appear in Chaos, Solitons and Fractals (2008

Regioselective Green Synthesis and Antimicrobial properties of full fused non mixed Heterocyclic Systems

One pot synthesis and reaction of triazinthione and triazinohydrazide derivatives with different electrophilic reagents in ordered to synthesis of some interesting non-mixed heterocyclic compounds. Structures of thiazolotriazine, triazolotriazine, pyrimidinyltriazine, and triazinotriazine derivatives were established via spectroscopic data and elemental analysis. The synthesized compounds were screened for their antimicrobial activity

Examining the Adoption of Prefabricated Construction Methods for Building Housing in Egypt

Prefabricated construction methods have become a key strategy to achieve sustainable development in building housing around the world. However, these methods are still used in a narrow context in building Egyptian housing. This research aims to examine the adoption of prefabricated construction methods for building Egyptian housing. To achieve the aim of the research, 28 performance criteria under economic, social, environmental, and technical categories were used to evaluate the performance of prefabricated and traditional on-site frame construction methods in building Egyptian housing. Multi-criteria decision-making techniques (MCDM): the Technique for Order of Preference by Similarity to Ideal Solution technique (TOPSIS) and the Importance Performance analysis technique (IPA) were used to contextualize the final findings. The results revealed that prefabrication can achieve a good level of performance in building Egyptian housing with some recommendations. Most causes that weaken the performance of prefabrication in Egypt are back to the strategic criteria including; the lack of construction practitioners\u27 knowledge, standardization availability, and customer perception. This research provides a notion about the prefabrication performance in building Egyptian housing by using the multi-criteria decision-making analysis

The Effect of Mineral Pigments on Mechanical Properties of Concrete

 Pigmented concrete exhibits artesian properties in addition to ordinary concrete properties, explicitly high strength, excellent durability, and weather resistance. However, the influence of several parameters that affect the characteristics of colored concrete should be studied; extensively. In this paper, the impact of the w/b (water/binder) ratio using color pigments on the mechanical properties such as compressive and flexural strengths of colored cement mortar prisms and cubes experimentally investigated. The experimental program included 21 mixes with six cubes and three flexural prisms specimens for assessing compressive and flexural strength, respectively. The blends included different water/binder ratios with values of 0.4, 0.5, and 0.6, in addition to several color pigments as a partial replacement of cement. The percentage of replacements altered between 0, 2.5%, 5% and 7.5% with two different shades of pigments consisting of red iron and green chromium oxide. Based on the experimental results, empirical expressions were generated based on Abram’s law to assess the relationship between the compressive strength of colored concrete and w/b ratio. The results revealed that the compressive and flexural strength of colored concrete is influenced by w/b ratio and partially replacement percentage of cement by color pigment not proportionally direct. Furthermore, the shade of pigments also has a different impact as well

Anti-thrombotic Coatings for Blood Contacting Medical Decives and Implants Based on Nitric Oxide Release

Blood-contacting medical devices, are often used to treat cardiovascular diseases. These implantable medical devices, even if labeled as biocompatible, can cause serious complications in patients. Thrombus formation and infection are the main causes of failure of these devices. In contrast to the healthy endothelium, which actively resists thrombosis, artificial surfaces promote clotting through a complex series of interconnected processes that include protein adsorption, adhesion of platelet, leukocytes and red blood cells, ending with thrombosis. Using a layer-by-layer thin film building strategy to form layers of polyethyleneimine (PEI) and iNOSoxy as NO-releasing coatings allows for assembly of multi-component protein/PEI films. Here, the iNOSoxy enzyme protein used is negatively charged and adsorbed onto the positively charged matrix layer, polyethyleneimine. When discs coated with PEI/iNOSoxy films are exposed to arginine, a source of reducing equivalent, and other required ingredients, nitric oxide is formed and released. We characterize the PEI/iNOSoxy thin films in terms of structure of iNOSoxy within the films as well as the amount of active concentration. Fourier transform infrared (FTIR) spectroscopic analysis characterized structure-activity relationships of these NOScontaining thin films. Cyclic voltammetry determined the active catalyst (iNOSoxy) concentration on the modified surfaces, and how this relates to enzymatic activity and resulting NO release fluxes from PEI/NOS-containing thin film. Platelet adhesion assays determined if the amount of platelets adsorbed on the PEI/iNOSoxy films is inversely proportional to the amounts of NO released from coatings.https://engagedscholarship.csuohio.edu/u_poster_2018/1026/thumbnail.jp