Approximated transverse deflection of sandwich beam with 2D-FG and ceramic face sheets and 1D-FG core

The approximated numerical deflection of a sandwich beam with two directional functionally graded (2D-FG) and ceramic face sheets and one directional functionally graded (1D-FG) core, namely SW2D1DC, is presented under uniform load and various boundary conditions. The finite element code written in Matlab is applied in this article to investigate the influences of material properties on transverse deflections. The results of this article are given and compared with other results in the references to verify the feasibility of the application. This study also provides some more information about the characteristics of SW2D1DC beams

An Influence of Recycled Concrete Aggregate and Treated Waste Water Containing 50% GGBS Content in Light weight Concrete Mixes

Extraction of natural aggregates is expensive and has a huge impact on the environment. The main issues in sand and gravel mining are the large areas that are affected, ground water level changes, illegal mining, unsuitability of desert and marine sand, and costs of transport. Metallurgical waste can be used as a substitute for natural aggregates, the waste is recycled and the use of natural aggregates is reduced. Environmental sources are diminishing every day and hence, usage of available sources become even more important..The novelty of this research reports the experimental examination of applying Recycled Aggregate (RA), Treated wastewater (TW) and GGBS in concrete. Four groups of mixes were developed (Groups NW, TW, NWG, and TWG) with each group consisting of four mixes, providing a total of 16 mixes. Group NW: 100% Natural Water (NW) with different percent ratio of RA contents Group TW: 100% Treated waste water (TW) with different percent ratio of RA contents Group NWG: 100% Natural Water (NW) and 50% GGBS (replacement with Portland cement [PC]) with different percent ratio of RA content Group TWG: 100% TW and 50% GGBS (replacement with PC) with different percent ratio of RA contents The test result are compressive strength tests after 1,7,15, and 28 days. The statistical analysis results showed that the effect on concrete compressive strength was only significant when 20% RA was used in concrete exposed to TWW with 50% replacement of GGBS

Soil To Plant Transfer Factors of Natural Radionuclides in Khat (Catha endulis) from Igembe South Subcounty, Kenya

This study evaluated the soil to plant transfer factors of khat (Catha endulis) to determine the absorption potential of natural radionuclides. Soil and leaves of Khat were sampled from Igembe south subcounty, Kenya and analyzed for concentrations of primordial radionuclides using a Thallium doped NaI gamma ray detector. Soil to plant transfer factors were calculated from activity concentrations and radiological safety of the ingested radionuclides was determined by annual effective dose (IAED), internal hazard index (Hin) and risk assessment parameter (RAP). Test results showed that the average soil to plant transfer factors for 232Th,238U and 40K were 0.0825, 0.143 and 1.575 respectively. The transfer factors of 40K were greater than 1 in more than 88% of the samples. The soil to plant transfer factors varies directly with energy of the gamma ray emitted and inversely with activity concentration of the radionuclides. The average IAED, Hin, and RAP were 1.136±0.390mSv/y, 0.210±0.070, 0.0568±0.021% respectively. Radiation hazard indices were within the safe limits and the fatality percentage was negligible. Therefore, there is no radiation risk associated with chewing of the sampled khat, and most of the radionuclides present in soil are not absorbed by Khat

Preparation and Study of the Physical Properties of CdSe Films Deposited by a Chemical Bath Method and Exposed to Neutron Irradiation: Effect of neutron irradiation on a CdSe film prepared

This study deals with the preparation of CdSe films using two sources of cadmium, (CdCl2) and (CdSO4), and studying the effect of neutron irradiation on their optical and structural properties. Using CBD method, the films were prepared on glass substrates at a temperature of 50 •C, with a deposition time of 3 hours. These films were exposed to the neutron beam from the radioactive source (Am241-Be10) with a neutron flux (3*105 n/cm2.s) and an energy of 5 MeV for 7 days. It was noted that neutron irradiation has a significant effect on the physical properties of the films. Using a UV-V spectrophotometer, the optical properties of the films were studied. It was found that the absorption coefficient (?) and the energy gap increase with irradiation, and from the following XRD, FESEM and EDX measurements, the shape and structure of the prepared and irradiated films were determined. X-ray measurements have shown that there are preferred directions for grain growth [111], [220], and [311]. It was also observed that the grain size increases, while the relative density decreases with irradiation. As for FESEM measurement, it was noted that the surface shape of the films is greatly affected when exposed to neutron radiation

An Optimized Sandwich Bumper Beam for Child Occupant Head Injury Prevention

Child fatalities from motor vehicle crashes are recently being considered as a global problem. Various mitigation systems have been proposed, but are still not optimum. Designing energy absorption vehicle front has been one of the methods used to minimize vehicle deceleration. This in addition to child restraint seat could help minimize child injuries especially to the most sensitive part of human body, the head. Sandwich bumper beam absorbs huge kinetic energy by plastic deformation and lead to reduction of vehicle deceleration and subsequent lower occupant injuries. In this work, optimization was carried out seeking for the optimum design of composite beam thickness ( and foam thickness (  of a sandwich bumper that will minimize Head Injury Criteria ( and ) to child occupant at 48 km/h frontal impact. Sampling design of the bumper and beam thickness applying design of experiment and finite element (FE) crash simulations using LS DYNA was applied to evaluate the three year old (3YO) child model head injury responses. Optimization models were developed which were in turn used in optimization process. The optimization was carried out using polynomial Response Surface Method (RSM) for  and . The bumper beam and foam thickness that gives a minimum   and  of 386.6 and 311.5 respectively are 100 mm  with 1 mm . Lastly, the work, suggested the need for employing the relationship that exist between child occupant response and bumper material and thickness in design considerations

Control of A Switched Reluctance Motor Based on Asymmetric Converter and Digital Signal Controller for Forward and Reverse Mode

The Switched Reluctance Motor (SRM) is one of the best choices for industrial and electric vehicle applications, selected for its optimal performance. This is due to the advantages of SRM, including the use of permanent magnet-free technology and a simple construction consisting of an iron core on the rotor and stator windings. A rotary encoder is utilized to detect the rotor position due to its high precision. However, synchronization with the rotor position is required during installation to achieve optimal SRM performance. The rotor position obtained from the rotary encoder is processed by the digital signal controller to determine the firing angle on the rotor. The research objective is to control the SRM to rotate in both directions. To support this study, laboratory tests were conducted for validation by changing the phase sequence in the asymmetric converter, causing differences in the three-phase current waveforms for forward and reverse rotations. The results of this research show that the SRM can rotate bidirectionally

Design and Implementation of a Three-Phase Asynchronous Motor Drive Based on a Single Chip Three-Phase Bridge Driver IR 2132

Technological developments in this world are growing quite rapidly, one of which is the development of the use of electric motors. There are many types of electric motors today, for example asynchronous electric motors or often called induction motors. In its use, asynchronous motors are widely used on an industrial scale. As time went by, asynchronous motor control itself also began to develop, starting from mechanically using switches to using inverters. The use of a three-phase IGBT inverter to control a three-phase asynchronous motor will be discussed in this research. The inverter control itself will use the SPWM topology, where the SPWM topology has advantages over the PWM topology. Apart from that, this research will use a single chip three-phase bridge driver IR2132 as the IGBT driver. This IC has advantages, one of which is that it has an internal deadtime, where deadtime is very necessary in controlling the three-phase inverter so that short circuits do not occur between the legs. This research shows that with a certain DC Link input voltage, it is possible to regulate a three-phase asynchronous motor using SPWM topology to control an IGBT inverter

Approximation of the buckling load in functionally graded beams with two types of porous distribution

For the purpose of studying the buckling behavior of functionally graded porous beams with one kind of porous distribution, a short article is given. Although the research topic is nothing special, based on the simple beam model related to the finite element method and MATLAB code, we can calculate the approximation of the buckling load of the beam under the influence of porosity. An example of buckling load estimates for this structure is given, which shows that our method is applicable to a certain extent

Summaries of Causes, Effects and Prevention of Solar Electric Fire Incidents

Currently the number of fire incidents involving photovoltaic (PV) systems are increasing as a result of the strong increase of PV installations. These incidents are terrible and immeasurable on life and properties. It is thus very important to understand the causes, effects and how prevent the occurrence of incidents. This study aimed to summarize the causes, effects, and preventions of solar electric fire incidents. Literature review was adopted to summarize the study. The summarized and discussed result from literature found that arcing, hot spot, weather conditions, improper installations and maintenance, and systems mechanical and electrical failures are the main causes solar PV fire incidents. The effects of incidents are terrible on life and properties. The result also discussed the precautionary measures in detail on how to prevent PV systems and firefighters before and during fire incidents. Therefore, it is expected that the study is comprehensive for manufacturers, installers, professionals to build and improve understanding of causes, effects and prevention of solar electric fire incidents in residential, industrial and commercial applications

Review on waste water reuse for irrigation towards achieving environmental sustainability

Even though water makes up around 70% of the earth's crust, just a small portion of it is suitable for terrestrial life. Water is essential for life. The small percentage of freshwater with low salt concentration in the Antarctic and Arctic (68.7%) is only 2.5% of the total water stock in the hydrosphere and is largely in the form of ice and permanent snow cover. This writing serves as a review. Journals, publications, and earlier project works pertinent to the subject at hand were thoroughly examined and strategically sampled. To gather the data needed for the paper's creation, many works were examined and summarized. Agriculture is a large consumer of wastewater globally. It is believed that finding suitable irrigation resources is crucial for protecting natural water bodies and ensuring food safety. Wastewater reuse has emerged as a practical option for pollution reduction when water reuse replaces effluent discharge to vulnerable surface water bodies, preserving and extending available water supplies. This is due to the difficulties associated with the discharge of untreated wastewater into the environment. As treating and utilizing wastewater for irrigation would make it easier to achieve sustainability, using wastewater for irrigation is an efficient strategy to lower costs and improve environmental health and safety in today's economy