Search results for: standard Rocchio’s formula

Authors: Maryam Ramezankhani

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The present research tries to study the possibility of formalizing the sense relation of hyponymy. It applied mathematical tools and also uses mathematical logic concepts especially those from propositional logic. In order to do so, firstly, it goes over the definitions of hyponymy presented in linguistic dictionaries and semantic textbooks. Then, it introduces a formal translation of the sense relation of hyponymy. Lastly, it examines the efficiency of the suggested formula by some examples of natural language.

Keywords: sense relations, hyponymy, formalizing, words’ sense relation, formalizing sense relations

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Authors: A. Guemache, M. Omari

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Oxides with formula Ca1-xSrx MnO3(0≤x≤0.2) were synthesized using co precipitation method. The identification of the obtained phase was carried out using infrared spectroscopy and x-ray diffraction. Thermogravimetric and differential analysis was permitted to characterize different transformations of precursors which take place during one heating cycle. The study of electrochemical behavior was carried out by cyclic voltammetry and impedance spectroscopy. The obtained results show that apparent catalytic activity improved when increasing the concentration of strontium. Anodic current densities varies from 1.3 to 5.9 mA/cm2 at the rate scan of 20 mV.s-1 and a potential 0.8 V for oxides with composition x=0 to 0.2.

Keywords: oxide, co-precipitation, thermal analysis, electrochemical properties

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Authors: James Moran, Anusarn Permsuwan

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This paper compares oscillations in the dry friction coefficient in different journal bearings. Measurements are made of the average and standard deviation in the coefficient of friction as a function of sliding velocity. The standard deviation of the friction coefficient changed dramatically with sliding velocity. The magnitude and frequency of the oscillations were a function of the velocity. A numerical model was developed for the frictional oscillations. There was good agreement between the model and results. Five different materials were used as the sliding surfaces in the experiments, Aluminum, Bronze, Mild Steel, Stainless Steel, and Nylon.

Keywords: Coulomb friction, dynamic friction, non-lubricated bearings, frictional oscillations

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Authors: Quan Wen, Tianxiao Chang, Shaolu Shi, Yushi Wang, Guangyu Wang

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As a kind of working environment of the fuze, the spin rate decaying law of projectile in exterior trajectory is of great value in the design of the rotation count fixed distance fuze. In addition, it is significant in the field of devices for simulation tests of fuze exterior ballistic environment, flight stability, and dispersion accuracy of gun projectile and opening and scattering design of submunition and illuminating cartridges. Besides, the self-destroying mechanism of the fuze in small-caliber projectile often works by utilizing the attenuation of centrifugal force. In the theory of projectile aerodynamics and fuze design, there are many formulas describing the change law of projectile angular velocity in external ballistic such as Roggla formula, exponential function formula, and power function formula. However, these formulas are mostly semi-empirical due to the poor test conditions and insufficient test data at that time. These formulas are difficult to meet the design requirements of modern fuze because they are not accurate enough and have a narrow range of applications now. In order to provide more accurate ballistic environment parameters for the design of a hemispherical head projectile fuze, the projectile’s spin rate decaying law in exterior trajectory under the effect of air resistance was studied. In the analysis, the projectile shape was simplified as hemisphere head, cylindrical part, rotating band part, and anti-truncated conical tail. The main assumptions are as follows: a) The shape and mass are symmetrical about the longitudinal axis, b) There is a smooth transition between the ball hea, c) The air flow on the outer surface is set as a flat plate flow with the same area as the expanded outer surface of the projectile, and the boundary layer is turbulent, d) The polar damping moment attributed to the wrench hole and rifling mark on the projectile is not considered, e) The groove of the rifle on the rotating band is uniform, smooth and regular. The impacts of the four parts on aerodynamic moment of the projectile rotation were obtained by aerodynamic theory. The surface friction stress of the projectile, the polar damping moment formed by the head of the projectile, the surface friction moment formed by the cylindrical part, the rotating band, and the anti-truncated conical tail were obtained by mathematical derivation. After that, the mathematical model of angular spin rate attenuation was established. In the whole trajectory with the maximum range angle (38°), the absolute error of the polar damping torque coefficient obtained by simulation and the coefficient calculated by the mathematical model established in this paper is not more than 7%. Therefore, the credibility of the mathematical model was verified. The mathematical model can be described as a first-order nonlinear differential equation, which has no analytical solution. The solution can be only gained as a numerical solution by connecting the model with projectile mass motion equations in exterior ballistics.

Keywords: ammunition engineering, fuze technology, spin rate, numerical simulation

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Authors: Imen Bouazzi

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The IEEE-802.15.4 standard utilizes the CSMA-CA mechanism to control nodes access to the shared wireless communication medium. It is becoming the popular choice for various applications of surveillance and control used in wireless sensor network (WSN). The benefit of this standard is evaluated regarding of the packet loss probability who depends on the configuration of IEEE 802.15.4 MAC parameters and the traffic load. Our exigency is to evaluate the effects of various configurable MAC parameters on the performance of beaconless IEEE 802.15.4 networks under different traffic loads, static values of IEEE 802.15.4 MAC parameters (macMinBE, macMaxCSMABackoffs, and macMaxFrame Retries) will be evaluated. To performance analysis, we use ns-2[2] network simulator.

Keywords: WSN, packet loss, CSMA/CA, IEEE-802.15.4

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Authors: Raquel Bayon, Ainara Lopez-Ortega, Elena Rodriguez, Amaya Igartua

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Corrosion is one of the most concerning phenomenon that accelerates material degradation in offshore applications. In order to avoid the premature failure of metallic materials in marine environments, organic coatings have widely been used, due to their elevated corrosion resistance. Thermally-sprayed metals have recently been used in offshore applications, whereas ceramic materials are usually less employed, due to their high cost. The protectiveness of the coatings can be evaluated and categorized in corrosivity categories in accordance with the ISO 12944-6 Standard. According to this standard, for coatings that are supposed to work in marine environments, a C5-M category is required for components working out of the water or partially immersed in the splash zone, and an Im2 category for totally immersed components. C5-M/Im-2 high category would correspond to a durability of more than 20 years without maintenance in accordance with ISO 12944 and NORSOK M501 standards. In this work, the corrosion behavior of three potential coatings used in offshore applications has been evaluated. For this aim, the materials have been subjected to different environmental conditions in several climatic chambers (humidostatic, climatic, immersion, UV and salt-fog). The category of the coatings to each condition has been selected, in accordance with the previously mentioned standard.

Keywords: cabinet, coatings, corrosion, offshore

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Authors: Jiahe Liu, Hongyang Yu, Feng Qian, Miao Luo

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SMPL-X was a powerful parametric human body model that included male, neutral, and female models, with significant gender differences between these three models. During the process of 3D human body reconstruction, the correct selection of standard templates was crucial for obtaining accurate results. To address this issue, we developed an efficient gender classification algorithm to automatically select the appropriate template for 3D human body reconstruction. The key to this gender classification algorithm was the precise analysis of human body features. By using the SMPL-X model, the algorithm could detect and identify gender features of the human body, thereby determining which standard template should be used. The accuracy of this algorithm made the 3D reconstruction process more accurate and reliable, as it could adjust model parameters based on individual gender differences. SMPL-X and the related gender classification algorithm have brought important advancements to the field of 3D human body reconstruction. By accurately selecting standard templates, they have improved the accuracy of reconstruction and have broad potential in various application fields. These technologies continue to drive the development of the 3D reconstruction field, providing us with more realistic and accurate human body models.

Keywords: gender classification, joint detection, SMPL-X, 3D reconstruction

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Authors: Ghania Zerari, Abderrezak Guessoum, Rachid Beguenane

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This paper introduces high-performance architecture for fully parallel stochastic Low-Density Parity-Check (LDPC) field programmable gate array (FPGA) based LDPC decoder. The new approach is designed to decrease the decoding latency and to reduce the FPGA logic utilisation. To accomplish the target logic utilisation reduction, the routing of the proposed sub-variable node (VN) internal memory is designed to utilize one slice distributed RAM. Furthermore, a VN initialization, using the channel input probability, is achieved to enhance the decoder convergence, without extra resources and without integrating the output saturated-counters. The Xilinx FPGA implementation, of IEEE 802.3an standard LDPC code, shows that the proposed decoding approach attain high performance along with reduction of FPGA logic utilisation.

Keywords: low-density parity-check (LDPC) decoder, stochastic decoding, field programmable gate array (FPGA), IEEE 802.3an standard

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Authors: G. Peker, Tolga N. Aynur, E. Tinar

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In order to determine the energy consumption level and cooling characteristics of a domestic refrigerator controlled with various cooling system algorithms, a side by side type (SBS) refrigerator was tested in temperature and humidity controlled chamber conditions. Two different control algorithms; so-called drop-in and frequency controlled variable capacity compressor algorithms, were tested on the same refrigerator. Refrigerator cooling characteristics were investigated for both cases and results were compared with each other. The most important comparison parameters between the two algorithms were taken as; temperature distribution, energy consumption, evaporation and condensation temperatures, and refrigerator run times. Standard energy consumption tests were carried out on the same appliance and resulted in almost the same energy consumption levels, with a difference of %1,5. By using these two different control algorithms, the power consumptions character/profile of the refrigerator was found to be similar. By following the associated energy measurement standard, the temperature values of the test packages were measured to be slightly higher for the frequency controlled algorithm compared to the drop-in algorithm. This paper contains the details of this experimental study conducted with different cooling control algorithms and compares the findings based on the same standard conditions.

Keywords: control algorithm, cooling, energy consumption, refrigerator

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Authors: Kritin K. Verma, Brian L. Ransdell

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White patches are a symptom of vitiligo, a chronic autoimmune dermatological condition that causes a loss of pigmentation in the skin. Vitiligo can cause issues of self-esteem and quality of life while also progressing the development of other autoimmune diseases. Current treatments in allopathy and homeopathy exist; some treatments have been found to be toxic, whereas others have been helpful. Allopathy has seemed to offer several treatment plans, such as phototherapy, skin lightening preparations, immunosuppressive drugs, combined modality therapy, and steroid medications to improve vitiligo. This presentation will review the FDA-approved topical cream, Opzelura, a JAK inhibitor, and its effects on limiting vitiligo progression. Meanwhile, other non-conventional methods, such as Arsenic Sulphuratum Flavum used in homeopathy, will be debunked based on current literature. Most treatments still serve to arrest progression and induce skin repigmentation. Treatment plans may differ between patients due to depigmentation location on the skin. Since there is no gold standard plan for treating patients with vitiligo, the oral presentation will review all topical and systemic pharmacological therapies that fight the depigmentation of the skin and categorize their validity from a systematic review of the literature. Since treatment plans are limited in nature, all treatment methods will be mentioned and an attempt will be made to make a golden standard treatment process for these patients.

Keywords: vitiligo, phototherapy, immunosuppressive drugs, skin lightening preparations, combined modality therapy, arsenic sulphuratum flavum, homeopathy, allopathy, golden standard, Opzelura

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Authors: Benjamin Lee Warren

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Many problems exist in additive number theory which is essential to determine the primes that are the sum of two elements from a given single-variable polynomial sequence, and most of them are unattackable in the present day. Here, we determine solutions for this problem to a few certain sequences (certain binomial coefficients and power sums) using only elementary algebra and some algebraic factoring methods (as well as Euclid’s Lemma and Faulhaber’s Formula). In particular, we show that there are finitely many primes as sums of two of these types of elements. Several cases are fully illustrated, and bounds are presented for the cases not fully illustrated.

Keywords: binomial coefficients, power sums, primes, algebra

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Authors: Akshay B. Pawar, Rohit Y. Parasnis

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Heart Rate Variability (HRV) is a widely used indicator of the regulation between the autonomic nervous system (ANS) and the cardiovascular system. Besides being non-invasive, it also has the potential to predict mortality in cases involving critical injuries. The gold standard method for determining HRV is based on the analysis of RR interval time series extracted from ECG signals. However, because it is much more convenient to obtain photoplethysmogramic (PPG) signals as compared to ECG signals (which require the attachment of several electrodes to the body), many researchers have used pulse cycle intervals instead of RR intervals to estimate HRV. They have also compared this method with the gold standard technique. Though most of their observations indicate a strong correlation between the two methods, recent studies show that in healthy subjects, except for a few parameters, the pulse-based method cannot be a surrogate for the standard RR interval- based method. Moreover, the former tends to overestimate short-term variability in heart rate. This calls for improvements in or alternatives to the pulse-cycle interval method. In this study, besides the systolic peak-peak interval method (PP method) that has been studied several times, four recent PPG-based techniques, namely the first derivative peak-peak interval method (P1D method), the second derivative peak-peak interval method (P2D method), the valley-valley interval method (VV method) and the tangent-intersection interval method (TI method) were compared with the gold standard technique. ECG and PPG signals were obtained from 10 young and healthy adults (consisting of both males and females) seated in the armchair position. In order to de-noise these signals and eliminate baseline drift, they were passed through certain digital filters. After filtering, the following HRV parameters were computed from PPG using each of the five methods and also from ECG using the gold standard method: time domain parameters (SDNN, pNN50 and RMSSD), frequency domain parameters (Very low-frequency power (VLF), Low-frequency power (LF), High-frequency power (HF) and Total power or “TP”). Besides, Poincaré plots were also plotted and their SD1/SD2 ratios determined. The resulting sets of parameters were compared with those yielded by the standard method using measures of statistical correlation (correlation coefficient) as well as statistical agreement (Bland-Altman plots). From the viewpoint of correlation, our results show that the best PPG-based methods for the determination of most parameters and Poincaré plots are the P2D method (shows more than 93% correlation with the standard method) and the PP method (mean correlation: 88%) whereas the TI, VV and P1D methods perform poorly (<70% correlation in most cases). However, our evaluation of statistical agreement using Bland-Altman plots shows that none of the five techniques agrees satisfactorily well with the gold standard method as far as time-domain parameters are concerned. In conclusion, excellent statistical correlation implies that certain PPG-based methods provide a good amount of information on the pattern of heart rate variation, whereas poor statistical agreement implies that PPG cannot completely replace ECG in the determination of HRV.

Keywords: photoplethysmography, heart rate variability, correlation coefficient, Bland-Altman plot

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Authors: Ahmed Abdolkhalig, Rastko Zivanovic

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This paper evaluates the Total Vector Error of an estimated Phasor as define in IEEE C37.118 standard within different medium access in Local Area Networks (LAN). Three different LAN models (CSMA/CD, CSMA/AMP, and Switched Ethernet) are evaluated. The Total Vector Error of the estimated Phasor has been evaluated for the effect of Nodes Number under the standardized network Band-width values defined in IEC 61850-9-2 communication standard (i.e. 0.1, 1, and 10 Gbps).

Keywords: phasor, local area network, total vector error, IEEE C37.118, IEC 61850

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Authors: Fethi Benyettou, Abdelkader Aissat, M. A. Benammar

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In this work, we use Silvaco TCAD software for modeling and simulations of standard GaAs solar cell, InAs/GaAs and GaSb/GaAs p-i-n quantum dot solar cell. When comparing 20-layer InAs/GaAs, GaSb/GaAs quantum dots solar cells with standard GaAs solar cell, the conversion efficiency in simulation results increased from 16.48 % to 22.6% and 16.48% to 22.42% respectively. Also, the absorption range edge of photons with low energies extended from 900 nm to 1200 nm.

Keywords: SILVACO TCAD, the quantum dot, simulation, materials engineering

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Authors: J. A. Mayouf, Q. A. Najim, H. S. Al-Bayati

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The concentrations of cadmium and lead in sewage sludge samples were determined by Atomic Absorption Spectrometric Method. Samples of sewage sludge were obtained from three sewage treatment plants localised in Middle Region of Libya (Misrata, Msallata and Tarhünah cities). The results shows that, the mean levels of Cadmium for all regions are ranges from 81 to 123.4 ppm and these values are higher than the limitations for the international standard which are not registered more than 50 ppm (dry weight) in USA, Egypt and the EU countries. While, the lead concentrations are ranged from 8.0 to 189.2 ppm and all values are within the standard limits which graduated between (275–613) ppm.

Keywords: cadmium, lead, sewage, spectrometry

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Authors: R. Kiš, M. Malcho, M. Janovcová

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This work aims to present a numerical analysis of the natural gas which flows through a high-pressure pipeline and an orifice plate, through the use of CFD methods. The paper contains CFD calculations for the flow of natural gas in a pipe with different geometry used for the orifice plates. One of them has a standard geometry and a shape without any deformation and the other is deformed by the action of the pressure differential. It shows the behaviour of natural gas in a pipeline using the velocity profiles and pressure fields of the gas in both models with their differences. The entire research is based on the elimination of any inaccuracy which should appear in the flow of the natural gas measured in the high-pressure pipelines of the gas industry and which is currently not given in the relevant standard.

Keywords: orifice plate, high-pressure pipeline, natural gas, CFD analysis

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Authors: Haoshu Li, Shaolong Wan

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The recent focus has been on directional signal amplification of a signal input at one end of a one-dimensional chain and measured at the other end. The amplification rate is given by the end-to-end Green’s functions of the system. In this work, we derive the exact formulas for the end-to-end Green's functions of non-Hermitian single-band systems. While in the bulk region, it is found that the Green's functions are displaced from the prior established integral formula by O(e⁻ᵇᴸ). The results confirm the correspondence between the signal amplification and the non-Hermitian skin effect.

Keywords: non-Hermitian, Green's function, non-Hermitian skin effect, signal amplification

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Authors: Asabe Ahmad Tijani, Y. A. Yahaya

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The paper considers the derivation of implicit Adams-Moulton type method, with k=4 and 5. We adopted the method of interpolation and collocation of power series approximation to generate the continuous formula which was evaluated at off-grid and some grid points within the step length to generate the proposed block schemes, the schemes were investigated and found to be consistent and zero stable. Finally, the methods were tested with numerical experiments to ascertain their level of accuracy.

Keywords: Adam-Moulton Type (AMT), off-grid, block method, consistent and zero stable

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Authors: Nangialai Yousufzai, Eysosiyas Etana, Ikuo Sugiyama

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Kabul population has been growing continually since 2001 and reaching six million in 2025 due to the rapid inflow from the neighboring countries. As a result of the population growth, lack of living facilities supported by infrastructure services is becoming serious in social and economic aspects. However, about 70% of the city is still occupied illegally and the government has little information on the infrastructure demands. To improve this situation, land readjustment is one of the powerful development tools, because land readjustment does not need a high governmental budget of itself. Instead, the method needs cooperation between stakeholders such as landowners, developers and a local government. So it is becoming crucial for both government and citizens to implement land readjustment for providing tidy urban areas with enough public services to realize more livable city as a whole. On the contrary, the traditional land readjustment tends to spend a long time until now to get consensus on the new plan between stakeholders. One of the reasons is that individual land area (land parcel) is decreased due to the contribution to public such as roads/parks/squares for improving the urban environment. The second reason is that the new plan is difficult for dwellers to imagine new life after the readjustment. Because the paper-based plan is made by an authority not for dwellers but for specialists to precede the project. This paper aims to shorten the time to realize quick consensus between stakeholders. The first improvement is utilizing questionnaire(s) to assess the demand and preference of the landowners. The second one is utilizing 3D model for dwellers to visualize the new environment easily after the readjustment. In additions, the 3D model is reflecting the demand and preference of the resident so that they could select a land parcel according to their sense value of life. The above-mentioned two improvements are carried out after evaluating total land prices of the new plans to select for maximizing the project value. The land price forecasting formula is derived from the current market ones in Kabul. Finally, it is stressed that the rapid consensus-building of land readjustment utilizing ICT and open data analysis is essential to redevelop slums and illegal occupied areas in Kabul.

Keywords: land readjustment, consensus building, land price formula, 3D simulation

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Authors: Fatima Ali Abbass, Hassan Ibrahim Rkein

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The number of entities worldwide that currently accept digital currency as payment is increasing; however, digital currency still is not widely accepted as a medium of exchange, nor they represent legal tender. At the same time, this makes accounting for cryptocurrency, as cash (Currency) is not possible under IAS 7 and IAS 32, Cryptocurrency also cannot be accounted for as Financial Assets at fair value through profit or loss under IFRS 9. Therefore, this paper studies the possible means to account for Cryptocurrency, since, as of today, there is not yet an accounting standard that deals with cryptocurrency. The request to have a specific accounting standard is increasing from top accounting firms and from professional accounting bodies. This study uses a mixture of qualitative and quantitative analysis in its quest to explore the best possible way to account for cryptocurrency. Interviews and surveys were conducted targeting accounting professionals. This study highlighted the deficiencies in the current way of accounting for Cryptocurrency as intangible Assets with an indefinite life. The deficiency becomes well highlighted, as the asset will then be subject to impairment, where under GAAP, only depreciation in the value of the intangible asset is recognized. On the other hand, appreciation in the value of the asset is ignored, and this prohibits the reporting entity from showing the true value of the cryptocurrency asset. This research highlights the gap that arises due to using accounting standards that are not specific for Cryptocurrency and this study confirmed that there is an urgent need to call upon the accounting standards setters (IASB and FASB) to issue accounting standards specifically for Cryptocurrency.

Keywords: cryptocurrency, accounting, IFRS, GAAP, classification, measurement

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Authors: Bentata Samir, Bendahma Fatima

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We have numerically studied the random trimer barrier AlxGa1-xAs superlattices (RTBSL). Such systems consist of two different structures randomly distributed along the growth direction, with the additional constraint that the barriers of one kind appear in triply. An explicit formula is given for evaluating the transmission coefficient of superlattices (SL's) in intentional correlated disorder. We have specially investigated the effect of aluminum concentration on the laser wavelength. We discuss the impact of the aluminum concentration associated with the structure profile on the laser wavelengths.

Keywords: superlattices, transfer matrix method, transmission coefficient, quantum laser

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Authors: M. Sanmi Awopetu, Olugbenga Aribisala, Olabisi O. Ologuntoye, S. Olumuyi Akindele

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Human existence vis-à-vis its environment is more and more getting a threatened sequel to air pollution occasioned majorly by human coupled with natural activities. Earth is getting warmer; ozone layer is getting depleted, acid rain is being experienced, all as a result of air pollution. This study seeks to investigate the effect of air pollution on dew water. Thirty-one (31) samples of dew water were collected in four locations in Ado- Ekiti, Ekiti State Nigeria. Analytical studies of the dew water samples were carried out to determine the pH, Total Dissolved Solids (TDS) and Electrical Conductivity (EC) in order to determine whether the dew water is polluted or not. There is no documented world standard for dew water quality. However, the standard for normal rain water which is pH between 5.0-5.6 and acid rain pH between 4.0-4.4 was adopted for this study. The pH of dew water samples collected and analyzed ranged between 5.5 and 7.9 in Olokun Ado-Ekiti while other samples fell in between this range. In Government Reserved Area (GRA), Ajilosun and EKSU school area, the pH ranged between 6.4 and 7.9 while EC fell in between 0.0 and 0.9 mS/cm which shows that the observed zones are polluted. Everyone has a role to play in order to reduce the pollutants being released into the atmosphere. There is a need to develop an international standard for dew water quality.

Keywords: dew, air pollution, total dissolved solids, electrical conductivity, Ado-Ekiti

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Authors: Ahmed M. Seyam, Rita Nemes, Salem Georges Nehme

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Europe and the United States have a worldwide significance in the field of concrete control and construction; according to that, a lot of countries adopted their standards and regulations in the concrete field, as proof of the Europe and US strong standards and due to lack of own regulations. The main controlled property of concrete are the compressive strength, flexure tensile strength, and modulus of elasticity as it relates both to its bearing capacity and to the durability of the elements built with it, so in this paper, ASTM standard and EN standards method of testing those properties were put under the microscope to compare the variations between them.

Keywords: concrete, ASTM, EU standards, compressive strength, flexural strength, modulus of elasticity

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Authors: Faraj Ahmed E. Alhegagi, Anagia M. Khamkam Mohamed, Bassam F. Alhajaji

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Duplex stainless steels (DSS) are widely employed in industry for apparatus working with sea water in petroleum, refineries and in chemical plants. Fracture of DSS takes place by cleavage of the ferrite phase and the austenite phase ductile tear off. Pop-in is an important feature takes place during fracture of DSS. The procedure of Pop-ins assessment plays an important role in fracture toughness studies. In present work, Zeron100 DSS specimens were heat treated at different temperatures, cooled and pulled to failure to assess the pop-ins criterion in crack initiation prediction. The outcome results were compared to the British Standard (BS 7448) and the ASTEM standard (E1290) for Crack-Tip Opening Displacement (CTOD) fracture toughness measurement. Pop-in took place during specimens loading specially for those specimens heat treated at higher temperatures. The standard BS7448 was followed to check specimen validity for fractured toughness assessment by direct determination of KIC. In most cases, specimens were invalid for KIC measurement. The two procedures were equivalent only when single pop-ins were assessed. A considerable contrast in fracture toughness value between was observed where multiple pop-ins were assessed.

Keywords: fracture toughness, stainless steels, pop ins, crack assessment

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Authors: G. Alston Rush, Gus A. Rush III, M. F. Horstemeyer

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This study compares the shell-facemask responses of four commonly used American football helmets, under the National Operating Committee on Standards for Athletic Equipment (NOCSAE) drop impact test method, to show that the test standard would more accurately simulate in-use conditions by modification to include the facemask. In our study, the need for a more vigorous systematic approach to football helmet testing procedures is emphasized by comparing the Head Injury Criterion (HIC), the Gadd Severity Index (SI), and peak acceleration values for different helmets at different locations on the helmet under modified NOCSAE standard drop tower tests. Drop tests were performed on the Rawlings Quantum Plus, Riddell 360, Schutt Ion 4D, and Xenith X2 helmets at eight impact locations, impact velocities of 5.46 and 4.88 meters per second, and helmet configurations with and without facemasks. Analysis of NOCSAE drop test results reveal significant differences (p < 0.05) for when the facemasks were attached to helmets, as compared to the NOCSAE Standard, without facemask configuration. The boundary conditions of the facemask attachment can have up to a 50% decrease (p < 0.001) in helmet performance with respect to peak acceleration. While generally, all helmets with the facemasks gave greater HIC, SI, and acceleration values than helmets without the facemasks, significant helmet dependent variations were observed across impact locations and impact velocities. The variations between helmet responses could be attributed to the unique design features of each helmet tested, which include different liners, chin strap attachments, and faceguard attachment systems. In summary, these comparative drop test results revealed that the current NOCSAE standard test methods need improvement by attaching the facemasks to helmets during testing. The modified NOCSAE football helmet standard test gives a more accurate representation of a helmet’s performance and its ability to mitigate the on-field impact.

Keywords: football helmet testing, gadd severity index, head injury criterion, mild traumatic brain injury

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Authors: Jung Ho Yang, Yong Soo Kim

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Electrical units are operated by electrical and electronic components. An environmental test sequence is useful for testing electrical units to reduce reliability issues. This study introduces test sequence guidelines based on relevant principles and considerations for electronic testing according to international standard IEC-60068-1 and the United States military standard MIL-STD-810G. Then, test sequences were proposed based on the descriptions for each test. Finally, General Motors (GM) specification GMW3172 was interpreted and compared to IEC-60068-1 and MIL-STD-810G.

Keywords: reliability, environmental test sequence, electrical units, IEC 60068-1, MIL-STD-810G

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Authors: Angelo Aloisio Dag, Pasquale Pasca, Massimo Fragiacomo, Ferdinando Totani, Gianfranco Totani

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The estimate of the velocity of shear waves (Vs) is essential in seismic engineering to characterize the dynamic response of soils. There are various direct methods to estimate the Vs. The authors report the results of site characterization in Macerata, where they measured the Vs using the seismic dilatometer in a 100m deep borehole. The standard Vs estimation originates from the cross-correlation between the signals acquired by two geophones at increasing depths. This paper focuses on the estimate of the dependence of Vs on the wavenumber. The dispersion curves reveal an unexpected hyperbolic dispersion curve typical of Lamb waves. Interestingly, the contribution of Lamb waves may be notable up to 100m depth. The amplitude of surface waves decrease rapidly with depth: still, their influence may be essential up to depths considered unusual for standard geotechnical investigations, where their effect is generally neglected. Accordingly, these waves may bias the outcomes of the standard Vs estimations, which ignore frequency-dependent phenomena. The paper proposes an enhancement of the accepted procedure to estimate Vs and addresses the importance of Lamb waves in soil characterization.

Keywords: dispersion curve, seismic dilatometer, shear wave, soil mechanics

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Authors: A. P. Puvanasvaran, Suresh A. L. Vasu, N. Norazlin

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The Lean Environmental Management Integration System (LEMIS) framework development is integration between lean core element and ISO 14001. The curiosity on the relationship between continuous improvement and sustainability of lean implementation has influenced this study toward LEMIS. Characteristic of ISO 14001 standard clauses and core elements of lean principles are explored from past studies and literature reviews. Survey was carried out on ISO 14001 certified companies to examine continual improvement by implementing the ISO 14001 standard. The study found that there is a significant and positive relationship between Lean Principles: value, value stream, flow, pull and perfection with the ISO 14001 requirements. LEMIS is significant to support the continuous improvement and sustainability. The integration system can be implemented to any manufacturing company. It gives awareness on the importance on why organizations need to sustain its Environmental management system. At the meanwhile, the lean principle can be adapted in order to streamline daily activities of the company. Throughout the study, it had proven that there is no sacrifice or trade-off between lean principles with ISO 14001 requirements. The framework developed in the study can be further simplified in the future, especially the method of crossing each sub requirements of ISO 14001 standard with the core elements of Lean principles in this study.

Keywords: LEMIS, ISO 14001, integration, framework

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Authors: Joanna Kufel-Orlowska

Abstract:

Domestic violence is a social threat to public safety and order. It poses a threat not only to the family members of the perpetrator but also disturbs the functioning of society and even the state. In a situation of danger, an individual either defends himself or/and calls for help by contacting an appropriate institution whose aim is to ensure civil security. Most often, such contact takes place through a telephone conversation, which is aimed at diagnosing the problem and prompt intervention. People in different situations and in different ways, despite the general reporting standards, try to inform about the need for help. The article aims to present the results of research on non-standard forms of reporting domestic violence in the opinion of the Polish society and operators of the Polish emergency number 112 (911). The research was conducted in the form of a survey technique on a sample of 160 operators (purposeful selection) and 300 people living in Poland (random selection). The research was conducted in the form of online surveys. The study found that in Poland: 1. emergency number operators often receive reports of domestic violence although they are not always able to diagnose whether the case is strictly about violence; 2. non-standard reports of domestic violence are received by about 30% of emergency number operators. Non-standard should be understood as reports of violence that deviate from the norm, are unusual, or are reported by a non-victim. 3. The most common forms of reporting violence not directly are: pretending to talk to a friend, calling a cab, making an appointment with a dentist/doctor, calling a store and helping with the selection of goods, asking about the bank's hotline, not speaking (in order for the emergency number operator to hear what is going on). 4. Emergency number operators in Poland are properly trained and are able to recognize the threatening situation of the reporting party and conduct the conversation in a safe manner for the reporting party. On the other hand, Polish people support the ability to report violence in a non-standard way and would do so themselves in the event of a threat to their own life, health, or property, thus expecting the emergency number operator to recognize a report and help us.

Keywords: domestic violence, operator of the emergency number 112 (911), emergency call center, reporting domestic violence

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Authors: Md. Ashikur Rahman

Abstract:

Optimal breastfeeding practice is essential to reducing childhood morbidity and mortality and helps to achieve Millennium Development Goal (MDG). A cross-sectional study was conducted in a rural area in Dhaka district to explore the barrier to optimal breastfeeding practices. The population of this study constitutes all nursing mothers having children aged 0-6 months, and they were selected purposively. The study adopted a structured and in-depth interview procedure consisting of open and closed-ended questions. Four hundred rural nursing mothers constituted the sample of the structured interview, while 15 were involved in the in-depth interview. Among the respondent's majority (67%) were in the age group 17-25 years, with a mean age of 24.44 years. Most (39.5%) of the mothers were housewives with a secondary level of education (46.5%). About 32% of mothers started breastfeeding within one hour after birth. But delayed initiation was reported in 31.5% of mothers, whereas 36.8% of mothers forgot the exact time of initiation of breastfeeding. The main reason not to practice colostrum was mothers tried to breastfeed, but there was no milk, stated 13.8% of mothers. In addition, about one-third (34.3%) of the respondents practiced pre-lacteal feeding, and among them, 12.8% introduced sugar with water. Reasons given by the mothers for bottle-feeding was that baby was not satisfied with breast milk only; 22.0% of mothers indicated this cause. The main influence to take formula milk by their mother and mothers-in-law was stated by 18.8% of mothers. Some mothers stated that major constraints to EBF were the perception of not having enough milk (25.5 %) and babies crying seems to be hungry (8.8%). One-third of the mothers (31.5%) felt uncomfortable during breastfeeding. Access to antenatal and postnatal counseling in the study area also was a key obstacle to optimal breastfeeding practices. In a qualitative survey, some mothers believed that there was no difference between breast milk and formula milk. Colostrum feeding, pre-lacteal feeding, early initiation of breastfeeding, and exclusive breastfeeding were strongly associated with family type, family member, birth order, religion, husbands' occupation, delivery attendants and delivery type, postnatal care, and health care facilities. To reduce the barriers to the successful practice of exclusive breastfeeding, there is a need for a grass-roots approach to educating and counseling nursing mothers with identifying factors influencing or discouraging the optimal practice.

Keywords: exclusive, breast feeding, practices, Bangladesh

Procedia PDF Downloads 75