bluuebunny/crossref_metadata_2025 huggingface dataset:
The possibility of Manufacturing Building Bricks from Al-Qend Hills Clays in North Iraq by using the extrusion and pressing methods
Authors: Abdullah Waleed R.
Published: July 2020

This study deals with the properties of Al-Qend Hills clays (Nineveh Governorate, North of Iraq) that effect on the production of building bricks and determines the best method for bricks industry. Two methods used to the manufacturing of clay brick samples, the first is the extrusion with dimensions (2.5×4×7.5) cm and the second is the pressing (cylinder shape) with dimensions (3.5×5.5) cm after that dried at room temperature for 48 hr. and for 24 hr. at 110 °C using the laboratory oven. After the drying process, the samples will burn at different temperatures (750, 800, 850 and 1100) °C according to burning program for 2 hr. in muffle furnace, The results appear that extruded samples at 800 °C is successful because conform to the requirements of Iraqi standards specification No.25, 1993.
Application of USLE and MUSLE Models for the Assessment of Soil Loss and Sediment Yield in Kuala Kari, Kelantan
Authors: Al-Ani Ibrahim Abdulrazak , Hussein Ola Ahmed
Published: July 2020

Soil loss is one of the most essential issues in the world. It is considered as the main source of sediment that introduces into the ambient environment and cause extensive impact to the. The objective of the current study is to estimate the soil loss and sediment yield by applying the Universal Soil Loss Equation (USLE) and Modified Universal Soil Loss Equation (MUSLE). Data from a real site which is located in Kuala Kari, Kelantan, Northern Malaysia was obtained and utilized in which the site is subdivided into five catchments. Results show that the sediment yield produced from all the catchments was very high which has a significant impact to the adjacent water bodies. It is recommended that erosion, sediment and drainage control measures need to highlighted in an Erosion and Sediment Control Plan (ESCP) to be installed in the site so as to minimize soil loss and sediments generated from the site.
Discharge Headway Time Distribution Model on Congested Signalized Intersections and their Operation Management: A Case Study in Baghdad City
Authors: Alkaissi Zainab Ahmed , Kadhim Ali Jabbar , Ali Saja
Published: July 2020

A discharge headway time is an essential parameter in the theory of traffic flow that largely utilized in various sections of engineering transport. Discharge time headway is a necessary traffic measure used widely in the analysis of signalized intersection. This research focuses on the comprehensive analysis and regression model of vehicle discharge headway at signalized intersections and applied operation management using upstream access points. A comparison of median and mean values of discharge saturation headway indicated that the median of (2.230sec.) is less than mean of (2.5272sec.). That means the concentration of small time headways and most of drivers select headways less than the mean value which cause high risk-potential for drivers and reduced safety performance at signalized intersections. Higher values of discharge headway were found to be (4.13sec.), (3.12 sec.) and (3.08sec.) for Al-Nakhala intersection, Al-Sakhara Intersection and Bairuit Intersection respectively The induced of upstream access management improved the saturation flow rate to (28%) for Al-Sakhara Intersection and (31%) for Al-Nakhala Intersection that indicated normal traffic operation with less congestion to a better operation conditions.
Experimental and numerical investigations on the behaviour of concrete filled steel tube and channel shear connectors in push-out tests
Authors: Alnebhan K M , Shallal M A
Published: July 2020

The use of shear connectors in the steel-concrete structural system is widely used to connect the steel and concrete parts of the system. The push-out test is the standard test used to detect the load capacity of different types of shear connectors. In this study, the push –out test was performed on concrete filled steel tube connected using channel shear connectors. The effect of concrete block strength and the exist of concrete core were investigated. Using concrete filled steel tube with increasing the compressive strength of the slab gain higher loading capacity and less slipping than hollow steel tube and low compressive strength of the concrete block. The experimental results were validated using ABAQUS finite element model. A numerical parametric study was carried out to show the effect of the value of concrete block compressive strength, length of the channel connectors, the strength of CFST and the yield stress of these connectors. It turns out that when increases either the length of shear connector or the concrete block strength or the yield stress of shear connector, the ultimate load increases, while the strength of CFST has no effect on ultimate load.
The Influence of Microbiology on Soil Aggregation Stability
Authors: Hashim Z E , Alzubaidi L A , Al-Madhhachi A T
Published: July 2020

In the present study, this work investigated the effects of bacteria (Bacillus sp.) decay and biological aggregating factors (organic matter, microbial calcium carbonate precipitation) at various steps on soil aggregate stability. Experiments carried out at different cultivation time 2, 5, and 8 weeks. The soil samples were compared the control (pure soil) versus soil treated with bacteria. The results showed that bacterial activity played an essential function in the macro-aggregate foundation. Nevertheless, the influence of organic matter (OM) on soil aggregate stability was important, which might be related to the microbial activity of bacteria to decay the organic material to an organic mineral that is connected with soil particles to form stable micro-aggregates. The CaCO3 is one of the most stable bonding agencies in nature as it is called natural cement, The soil aggregates stability increased as calcium carbonate increased. No change of soil pH levels observed due to microbial reactions with soil. Hence, the appropriate pH was 7.5. In addition, the higher pH decreases enzymatic activity and carbonate tends to dissolve at pH levels are very low. This study affords the helpful of soil stabilization in the presence of natural cementation of bacteria in contrast with the previous studies.
The Effect of Micro-Steel Fiber on the Corrosion Steel Reinforcement
Authors: Mohamed Shaymaa Abdelghany , Sultan Ahmed
Published: July 2020

There are many possible sources of ion chloride which can be open to concrete during service. Structure thesaurus to the sea may be sprayed with salt mist or seawater carried by the wind. In order to understand the behaviour of structures, different levels of corrosion must be studied. The current study has been taken up to investigate the behaviour of Reinforcement Concrete beams (RC) and bond strength of specimens exposed to 5% chloride solution, to cause corrosion of reinforcement. Two types of mixing by using Ordinary Portland Cement (OPC) type (I) concrete (with and without using micro steel fiber Vf =1.2) to cast eight reinforce concrete supported simply beam. Corrosion was accelerated using electrical current with different density to cause mass loss in steel bar with different levels of 6 %, 10 %, and 16 %. The results of the bond test and beams show a decrease in capacity with increasing the corrosion. The micro steel fiber causes an increase in bond strength of concrete ranged from (40-60%), and an increase in ultimate strength of beams ranged from (4 to 38 %) as compared with the beam without steel fiber.
Utilizing Device to Device Communication in Cellular Networks with the distance-based model selection method
Authors: Rahi Kareem Dhahir , Hasan Yousif Mohsin
Published: July 2020

The recent advances in the technology of smart devices caused a tremendous increase in wireless traffic in conventional cellular networks, thus leading to overloading the base station, and hence delaying the response to users’ requests. To overcome this, Device to Device (D2D) communication has been proposed recently to alleviate the traffic congestion at the base station (BS) by establishing a direct link between users. However, deciding whether a communication should be performed directly via D2D mode or via the base station is considered one of the challenges of applying such a method. Therefore, a mode selection based model was presented in this paper. The method depends on the probability of a user’s proximity close to 1.0. Furthermore, the proposed method also takes into account the interference with both; other cellular communication and D2D communication. The simulation results showed that a significant reduction in the delay can be achieved when responding to user requests after using the proposed model selection method. The increase in frequency reuse within the cell is considered as the main reason behind this behavior. Also, for a more simplified and less complex model selection method, it is more appropriate to apply the proposed model selection method to only the cell edges.
A Review on the Utilization of Phase Change Materials forSpace Cooling Purposes
Authors: Mohammed Tawfeeq W. , Abdulrehman Mohammed A.
Published: July 2020

Thermal energy storage systems have been investigated for the last decades, even though the information is quantitatively enormous with a few application works. In this study, a review has been carried out for the applications of phase change materials in the cooling of buildings, where these materials have tendency to gain extra heat (latent heat) during solid–liquid phase change. The study presents significant information regarding the use of phase change materials for cooling with many considerations like: climate conditions, types of phase change materials and their thermo-physical properties. Theresultant studies show that the integration of phase change material in the building have a good potential for reducing energy demand for cooling, further investigations are needed to really assess their benefits.
Analysis of Materials Applied In Cooling Systems Of Led Lighting
Authors: Kadium Akeel Hssain , Hussein Abdulrazzaq Abdzaid , Abdulwahid Qasim Saad
Published: July 2020

In this article, the problems associated with the removal of heat from the LEDs are considered. Brief information about the materials included in the cooling system of LED lighting is presented. A comparison of materials such as copper, aluminum and alumo nitride ceramics, the use of which is possible in cooling systems of led lighting is conducted. Analyzing the current market relations that have a significant impact on the cost of metals, even in material terms, the use of a copper radiator does not look very expensive. Methods for calculating the heat removal are proposed, an example of the calculation is given. It was shown that at elevated operating temperatures, the lifetime of the LEDs is significantly reduced: at 105 °C, the lifetime of the LEDs is 200 thousand hours less than at 85 ° C. The maximum area of the plate on which the LED is installed, for its effective cooling, is about 24 cm2 for a 1 W LED power.
Replacement of Natural Gravel with Waste Glass in Concrete
Authors: Fahad Besma M , Ali Nisreen S
Published: July 2020

In this work, sheet glass waste was used as a replacing material instead of natural gravel. The mix proportion of cement-gravel - sand was (1:1.5:3) and natural gravel was subjected in each mix at different percentages (10%, 20%, 30%, 40%, and 50%) all the specimens made with natural gravel were repeated with the same specification but instead of natural gravel, sheet glass waste were subjected. Compressive strength for cubic specimens were tested after immersing for different period (1, 7, 14, 28) days and a comparisons made between the concrete of waste glass with the conventional, concrete. Because of similarity of thestrength of compressive results of both glass and gravel. concrete, it was concluded that glass waste could replace natural gravel in concrete. It was obvious that all the percent’s show this behavior, but still at a particular percent’s glass concrete results were even better than gravel concrete. On the other hand glass concrete specimens were less absorbing than gravel concrete when studying the water absorption. Beside the maximum immersion time is the best to improve the properties to both series (glass, gravel).
Numerical and Experimental Analysis to Predict Life of Removable Partial Denture
Authors: Abbod Esraa A. , Al-Waily Muhannad , Al-Hadrayi Ziadoon M.R. , Resan Kadhim K. , Abbas Saif M.
Published: July 2020

Specialist has attempted to treat or replace teeth in case of human dental damage as a result of illness or misuse at certain stages of life. Alternating force affects the life of teeth, and this force causes failure. In this study, partial molar denture was manufactured from a composite material, including polymethylmethacrylate acrylic with zirconia, at different weight fractions (0, 2.5, 5 and 7.5 wt%). Mechanical tests (compression and hardness) were conducted for these samples, and the best weight fraction was selected to manufacture the partial molar denture. The chewing force was measured using a F-sensor. Numerical solution was achieved using the solid work software to determine the best sample and study the distribution of the dental stresses. To predict the life of the denture experimentally, we designed and manufactured a new device that can determine the life of the dental by applying alternative load which simulates the force generated by chewing.
Using Hydrogen Blends as Fuel in a Swirl Burner
Authors: Abdulsada Mohammed H.
Published: July 2020

Lean premixed combustion using hydrogen fuel blends is important for reducing carbon emissions to the environment in the forthcoming technology of gas turbine combustors. In relative terms, pure hydrogen shows promise as a likely upcoming fuel for use in power generation. This is achieved by new burner designs that use a low fuel equivalence ratio (having a great calorific value of hydrogen) and burn to release relatively low NOx emissions. This article explains extensively the experimental results of the swirl burner model using pure hydrogen and hydrogen-enriched methane blends. In addition, the paper discusses the problems of flashback and blowoff and the ability to switch fuels. However, fuel blends that use a high hydrogen percentage give significantly less working operational area between flashback and blowoff when compared to CH4. Safety problems are one of the challenges in using hydrogen blends, and there is a potential for serious danger because of the high rates of burning of the fuel mixture, the propensity for flashback, and the high degree of combustion instability sometimes caused in quenching the flame. Coke oven gas (COG) has a high hydrogen percentage and provides less operational area. Blowoff limits were found to improve as the outlet velocity increased and can be further mitigated with flame confinement.
Fatigue Behavior of Aluminum SiC Nano Composites Material with Different Reinforcement Ratio
Authors: Mamoon A. , Al-Jaafari A.
Published: July 2020

The fatigue properties of The Aluminum alloy (6061) metal matrix Nano composites (MMNC
s
), with different ratio of SiC wt nano particles (0.5, 1.0, 1.5, 2.0 and 2.5%.) to fabricated by stir casting were been investigated with rotating bending type of load and the stress ratio(R=-1) at room temperature. The composite were reinforced by SiC of 10 Nanometer in grain size to. The fatigue strength and life were been obtained experimentally by using S-N curves for different ratio wt % nano particles. The highest fatigue strength and life were occurred at .2.0 wt. % nano particles due to reasonably uniform distribution reinforcement of nano particles and minimal the porosity. The enhancement percentage in endurance fatigue limits are 11.48 % and 11.05% for 107 and 5*108 cycles respectively.
Power Flow and Efficiency Analysis of a Ravigneaux Hybrid Transmission
Authors: Juber Anahed H , Esmail Essam L , Mosa Muhanad H
Published: July 2020

In urban mobility, special attention must be paid to the energy requirements in vehicles, air quality and noise pollution. This can be achieved in two ways: the first is the use of low-emission hybrid vehicles, the second is the use of gear transmission system with improved efficiency. Both will reduce fuel consumption and provide more environmental protection. In the current work, a low-emission Ravigneaux hybrid transmission with thirteen operation modes is shown to be feasible. A fuel-efficient strategy is developed to control the fuel consumption of hybrid modes and reduce emissions. An efficiency analysis for all driving modes of the Ravigneaux hybrid transmission is conducted. The concept of potential power is used to determine the power ratios of any three links in the fixed reference frame (FRF) when the input link in the moving reference frame (MRF) is predictable. A single equation is developed that can be manipulated to determine all the powers flowing through the train. A numerical example is provided to give a complete view of the expected efficiency values. The proposed Ravigneaux hybrid transmission is found to be suitable for urban rather than external routes. The results can provide a theoretical bases for design works of hybrid transmissions with complex planetary gears.
Effect of friction stir welding on microstructure and mechanical properties of the 6061 aluminium alloy/15vol % SiCp reinforcement
Authors: Dawood H I , Musa Kanaan Mohammad , Abbas Rafid K , Alshemary Kassim Kadhim Hameed , Uday M B , Jaddan Riyam I , Taklef Leana J
Published: July 2020

In this article, the microstructure and mechanical properties of friction stir-welded joints were evaluated after 15 vol. % of silicon carbide particle (SiCp) were introduced into the joint line, then compared with another welded joint without using SiCp. The rotational speed of 1750 rpm was applied during the friction stir welding (FSW) process. The microstructure was assessed at the stir zone (SZ) using Field Emission Scanning Electron Microscopy (FESEM), and results showed a banded structure of the particle-rich region of SiCp. The ultimate tensile strength (UTS) was enhanced by 79.6 %, due to the presence of SiCp. This strength increased significantly due to the pinning effect and enlarged nucleation sites associated with the SiCp. Furthermore, the reinforced particles induced the fracturing of the primary grains and showed higher ductility when compared with the SiCp-free specimen.
Effect of Nano TiO2 on Static Fracture Toughness of Fiberglass/Epoxy Composite Materials in Hot Climate regions
Authors: Al-Ameen Ehsan Sabah , Abdulla Fadhel Abbas , Ogaili Ahmed Ali Farhan
Published: July 2020

This work is an experimental and numerical approach to analyze the effect of Nano powder additives and temperature on the critical crack length in fiber reinforced composite materials (FRC) exposed to uniaxial tensile load. Fiberglass/Epoxy compact tension test samples (CT) are prepared according to ASTM
standard E399
. Tio2 Nano powder is added by 2% wt to the resin to other samples. The static tensile test is applied to the samples and the results for crack length/time are discussed. ABAQUS/CAE software is used to simulate the case. The numerical and experimental results were close. The experimental results showed that the addition of 2%wt Tio2 Nano powder increased the critical crack length by 32.4%. The effect of ambient temperature is studied too by applying the experimental test on the fiberglass/Epoxy samples in room temperature (30°C) once and at outdoor (60°C) temperature. The results showed that the effect of the temperature increase decreased the critical crack length by 51%. The numerical results determined the fracture toughness (KIC) for the fiberglass/Epoxy samples to be 491 pa.mm0.5 and

517
pa.mm0.5 for the fiberglass/Epoxy-Nano powder samples.
Improvement fatigue life of polymer matrix composite by reinforcement with carbon nanotubes
Authors: Sadiq Ghanim Sh
Published: July 2020

This work, cover an improvement in fatigue life polymer matrix composite reinforcement with Carbon Nanotubes (MWCNT), by adding the reinforcements of Carbon Nanotubes to increase the fatigue strength. Three different percentage volume fractions added to the polymer matrix 3%, 5% and 7% to investigate which composition is more efficient and power full in mechanical application. The investigation was conducted experimentally deals with fabricated the tensile and fatigue specimens and evaluate the mechanical properties and the fatigue strength using the different volume fractions of Carbon Nanotubes and numerically by using Ansys software. Experimental results are compared with those obtained numerically using the finite element technique adopting. The comparison has shown a good agreement between the two techniques with a maximum discrepancy of (6.4%). Also, the results indicate that the reinforcement of the polymer by Carbon Nanotubes increase the fatigue limit, as the volume fraction increase the improvement of fatigue life increased.
Magnetohydrodynamics Mixed Convection Effects on the open enclosure in a horizontal channel Heated Partially from the Bottom
Authors: Al-Farhany Khaled , Alomari Mohammed Azeez , Faisal Ahmed Essa
Published: July 2020

This paper presents a numerical simulation of MHD effects on laminar fluid flow throws a two-dimensional channel with an open cavity heated partially from the bottom with a constant length for the heated wall. A constant speed fluid flow (air) inters the horizontal channel at constant cold temperature and all the walls assumed to be insulated accept the heated wall at the bottom of the open cavity. In this study, COMSOL Multiphysics® Modelling Software (5.5) have been selected to solve the governing equations The results are carried out with a verity range of Richardson number and Hartmann number, while the Reynolds number and Prandtl number are kept constants (Re= 100, and Pr=0.707). The result shows that the heat transfer increases with increasing of the Richardson number, while it decreases with the increase of the magnetic field effects.
Chemical Sensitization for Electric Properties Improvement of PBDB-T-SF Polymer for Solar Cells Application
Authors: Hrostea L , Leontie L , Girtan M
Published: July 2020

This paper reports the effect of ferric chloride (FeCl3) sensitization on poly [(2,6 (4,8 bis (5(2ethylhexylthio)4fluorothiophen2yl)benzo[1,2b:4,5b’]dithiophene))-alt-(5,5-(1’,3’-di-2-thienyl-5’,7’-bis(2-ethylhexyl)benzo[1’,2’c:4’,5’c’]dithiophene4,8 dione)] (known as PBDB-T-SF) in thin films (93 nm thickness), spin coated onto glass and ITO substrates. The optical properties do not undergo significant changes after FeCl3 immersion. Instead, FeCl3 sensitization leads to a dramatic decrease in resistivity of seven orders of magnitude comparing to the pristine thin films. This change is not stable over time, depending on FeCl3 solution concentration and polymer thin-film thickness, but remains remarkable after a new immersion.
Corrosion Protection of Metallic Surfaces in Peroxide – Surfactant Formulations
Authors: Chican I E , Vărășteanu D , Fierăscu I , Fierăscu R C , Calancea I-L , Petre R
Published: July 2020

Formulations containing surfactants and oxidizing agents can be used to neutralize hazardous material from different surfaces contaminated in cases of chemical aggressions. The formulations act chemically through different mechanisms on hazardous materials, transforming them into inactive agents. The surfactants are used to solubilise the slightly soluble chemical warfare agents and catalyse their decontamination. In this work we evaluated the stability of surfactants in hydrogen peroxide solutions, the surface active properties of surfactants system and also performed a study of the different types of surfactants, including amino acid-based surfactants, and corrosion inhibitors in an aqueous solution of hydrogen peroxide to identify the mixture that better protect the surfaces against corrosion. Corrosion tests were performed on cast iron and aluminum surface, evaluating the pinching, staining as well as staining color intensity of the surface at 24 hours after the solution is deposited on the surface. Based on the results obtained, formulations containing a system of three surfactants and a corrosion inhibitor in an aqueous solution of hydrogen peroxide were selected.
Synthesis of Carbon Quantum Dots from Food Products by Hydrothermal Carbonization Method
Authors: Iwińska Z , Pietrusiewicz P
Published: July 2020

The article describes the preparation and filtration of a solution containing carbon quantum dots. In this paper carbon quantum dots were obtained from food products, cheap and environmentally friendly hydrothermal carbonization method, without using toxic chemicals reagents. Moreover, to study the optical properties of the carbon quantum dots UV-VIS absorbtion were carried out. The maximum absorbance was determined in the range of λ ∼377 to ∼408nm. Furthermore, carbon quantum dots were found to emit green light.
Methods for Assessing the Freeze-Thaw Resistance of Road Concrete Used in our Country and at European Level
Authors: Nicula L M , Corbu O , Iliescu M
Published: July 2020

The paper addresses three methods of assessing the freeze-thaw resistance of road concretes prepared with conventional and artificial materials. The blast furnace slag was used, as an artificial material, in granulated and milled form and in the form of crushed aggregates from the steel industry. The most common method used in our country to determine the freeze-thaw resistance is the destructive method by measuring the variation of the compressive strength of the samples subjected to repeated freeze-thaw cycles. The most severe method of testing the freeze resistance considered at the European level, is based on the calculation of the amount of exfoliated material in the presence of defrosting agents. Another method used is to determine the values of the dynamic modulus of elasticity after repeated cycles of freeze-thaw. The results obtained were interpreted according to different evaluation criteria and compared with limit values proposed by the standardized methods.
Magnetic Properties of Composites Based on Amorphous Iron Alloys Produced with the Use of a Non-Magnetic Binder and Covered with High Temperature Varnish
Authors: Jez B , Jez K , Nabialek M
Published: July 2020

The continuous increase in the demand for electricity causes the need to search for new energy sources and to look for savings during its transmission. One of the areas of interest are materials dedicated to low loss transformer cores. Due to good magnetic properties, amorphous and nanocrystalline iron-based alloys are used in this area. The limited dimensions of these materials make their application difficult. Magnetic composites based on ferromagnetic amorphous alloys are a new direction of research. Usually, composites are made using a non-magnetic binder. However, the separation of magnetic particles worsens the magnetic properties. The solution to this problem may be production of composites coated with high temperature varnish. As part of the work, the results of research on the structure and magnetic properties of composites based on amorphous iron alloys are presented. Composites were made with 0.5% resin by mass and without resin covered with high temperature varnish. Material produced without the use of resin had a lower coercive field value.
Reliable Method and Multistage Process Involved in the Production of Activated Carbon Based on Raw Material-A Systematic Review
Authors: Muzarpaar S , Leman A M , Rahman K A , Rahim S Z A
Published: July 2020

Activated carbon AC) has versatile usage in the modern days for water treatment, air filtration and for multipurpose adsorption. Carbonaceous material with highly developed porosity known as AC after some process took place. AC also known as artificial materials characterized by the high surface area and the extensive surface chemistry. Significant adsorptive properties of the materials according to extensive surface chemistry which are responsible for the surface properties. Nowadays, AC are widely used in a large range of applications, for example medical uses, catalysis, gas storage, removal of pollutants and odors, gas separation and purification. Important Character for based materials of AC, it must accessible, affordable price, and with valorization potential in agricultural residues and industrial base. The most important raw materials for the production of AC is lignocellulosic materials. Over the time researcher around the world conducting research to improvised and perfecting the method for producing the AC. The aim of this paper is to critical review the reliable method for AC production. The process involved in the production of activated were pre-carbonization process (PCP), carbonization process (CP), and activation process (AP). Carbonization either using furnace or microwave. For AP, there are two main activation used namely chemical activation CA) and physical activation (PA). However there also combination of chemical and physical activation which called physiochemical activation (PCA).
A Review Regarding the Use of Natural and Industrial by-products in the Production of Geopolymer Binders
Authors: Ionescu B A , Lӑzӑrescu A
Published: July 2020

Rapid growth in population has led to the generation of large amounts of waste and environmental degradation. Environmental protection for future generations and to preservation of the already limited mineral resources, could be obtained with sustainable solutions for traditional Portland Cement Concrete. In order to produce geopolymers binders, raw materials rich in aluminum and silicon are alkali-activated. Some of the raw materials, for the production of the geopolymer binders can be obtained from natural sources, such as kaolin, metakaolin (calcined kaolin), diatomite, volcanic rock, etc., or industrial waste arising from production processes, such as fly ash, iron slag, blast furnace, granulated blast furnace slag, silica fume, marble dust, etc. The aim of this paper is to present relevant data in the field of alkali-activated geopolymer materials and study the opportunities of using Romanian mineral local raw materials in order to produce these types of binders.
The Influence of Blast Furnace Slag on Abrasion Resistance for Road Concretes
Authors: Nicula L M , Corbu O , Iliescu M
Published: July 2020

In this study, the blast furnace slag was used as a mineral addition in the projected road concrete mixtures, and the blast furnace slag in the form of aggregate at 0/4 mm size was used as a percentage of 20%, 40% and 60%. Three concrete slag mixtures were compared with two other concrete mixtures made with conventional materials. Compared to the first conventional mixture, milled slag used as a 15% addition and compared to the second conventional mixture milled slag was used as a substitute for 13% of Portland cement mass. The wear / abrasion resistance was evaluated at the concrete age of 100 days, respectively 150 days. The results indicated the highest wear resistance for the mixture with 20% aggregates crushed from furnace slag, and the mixture with 60% substitution aggregates from furnace slag was observed the lowest resistance. The tendency of evolution of the wear resistance is similar to that of the compressive strength. Mixtures with the highest compression strength also recorded the lowest volume loss after the abrasion test (Bohme). Compared to the first mixture made with conventional materials, the wear resistance obtained in blast furnace slag mixtures is lower. However, mixtures with 13% ground slag and up to 40% of aggregates crushed from blast furnace slag have higher wear resistance compared to the second mixture made with conventional materials.
Possibilities for Use of Vermiculite in Recultivation of Embankments Obtained as a Result of the Deposit of Mining Waste from the Extraction of Copper Ores
Authors: Stefanova V , Petrov P , Zheleva E
Published: July 2020

The present study examines the possibilities for vermiculite usage for recultvation of copper mining waste embankment. For this purpose, a laboratory study was carried out. The study which included the mixing of mining waste with different ratios of vermiculite and adds of other soil improvers (fertilizers and lime) with different norms. As a result is, is observed that the vermiculite addition in larger quantities did not affect the pH of the substrate. The content of major pollutants in the waste - Cu and As, remains relatively high - over the maximum permissible concentrations. Independently of the added vermiculite, it is necessary to apply calcium materials and fertilizers to improve substrate properties.
Intelligent Communication, Specific to the Engineering of Materials, under the Conditions of Ensuring the Circular Economy and Technological Digitization
Authors: Vescan M M , Soporan V F , Pӑdurețu S , Lehene T R , Crișan M D
Published: July 2020

The paper presents the problem of meeting the conditions imposed by the circular economy with direct references to a field of materials engineering, the manufacture of castings. The study has several motivations, one related to the analysis of the ways in which the development of the circular economy can be achieved by a company producing castings. The second one is to establish the partnerships that are necessary in order to materialize the conditions in the castings industry. The third motivation, based on the analyzes carried out at the level of the first two, aims at calibrating the communication for the actors that contribute to the realization of the circularity desideratum in the industrialization of the cast products in the new conditionings of the digitization instruments. To structure an action methodology in the direction of intelligent communication, specific to materials engineering, the paper is structured as follows: the conditions and values to which the circular economy is reported, the engineering design elements of solutions for a circular economy, communication partnerships, analysis of development measures of the circular economy in partnerships and the results of the analysis of the expected activities and partnerships.
Toxic Gas Eliminator from Print Ink by Applied High Frequency High Ripple Pulse Corona
Authors: Ketkaew S
Published: July 2020

This paper presents the design and development of toxic gas eliminator from print ink using high frequency high ripple pulse corona technique for decrease VOCs gas in the suction gas of printing ink using high voltage AC switched mode power supply. Using mini inverter principle and control of the switching by IC No.MB3579. The inverter is designed to operate at 10 kHz to 20 kHz through a high voltage switching transformer at output voltage of 1.5 kV, and at the input voltage of 18 VAC 50 Hz, By adapting the non-uniform electric field to the electrode design 3 tubes, one - hour operating yields the ozone gas (O3) generating capacity of 6.3 ppm enables decrease VOCs gas as well.
Real-time fluorescence sensing of single photoactive proteins using silver nanowires
Authors: Sulowska Karolina , Wiwatowski Kamil , Ćwierzona Maciej , Niedziółka-Jönsson Joanna , Maćkowski Sebastian
Published: July 2020

We demonstrate that single functionalized silver nanowires form a geometric platform suitable for efficient real-time detection of single photoactive proteins. By collecting series of images using wide-field fluorescence microscopy, events of single protein attachment can be distinguished with the signal to noise ratio further improved by fluorescence enhancement due to plasmon excitations in the nanowires. The enhancement is evidenced by strong shortening of the fluorescence decay of single photoactive proteins conjugated to the silver nanowires.
Negative resistance, capacitance in Mn/SiO2/p-Si MOS structure
Authors: Ashery A , Elnasharty Mohamed M M , Khalil Ahmed Asaad I , Azab A A
Published: July 2020

In this work is that we have manufactured a new structure that had not been studied by researchers before. This structure is Mn/SiO2/Si was synthesised by liquid phase epitaxy (LPE) as a metal-oxide- semiconductor (MOS) and can be used as a tunneling diode; demonstrated from I–V measurement and negative resistance. The structure and its characterization were examined by scanning electron microscope, XRD diffraction, C-V and I–V measurements. We studied the temperature, voltage dependence of dielectric and electrical parameters of the fabricated Mn/SiO2/P-Si MOS device. I–V measurements for this structure display diode tunnel behavior with negative resistance. Parameters such as series resistance (Rs), permittivity (ε′), dielectric loss (ε″), a tangent of the dielectric loss factor (tan δ), real and imaginary parts of electrical modulus (M′ and M″) and ac conductivity were examined in a temperature range of 303–393 K and frequency range (10 Hz–20 MHz) under 1 Vrms applied voltage along with dc bias range of (−2.0–2.0 V). We found that thermal reordering of the interface is a reason for a continuous density distribution of interface states with homogenous relaxation time, which in turn induced a higher sensitivity to both C and G/w response with electric field frequency. The device showed negative values for capacitance (C), dielectric loss (ε″), and dielectric loss tangent (tan δ) at all temperatures.
CV-MDI-QKD with coherent state: beyond one-mode Gaussian attacks
Authors: Ottaviani Carlo , Spedalieri Gaetana , Braunstein Samuel L , Pirandola Stefano
Published: July 2020

A general security proof of continuous variable (CV) measurement device independent (MDI) quantum key distribution (QKD) should not be automatically reduced to the analysis of one-mode Gaussian attacks (in particular, independent entangling-cloner attacks). To stress this point, the present work provides a very simple (almost trivial) argument, showing that there are an infinite number of two-mode Gaussian attacks that cannot be reduced to or simulated by one-mode Gaussian attacks. This result further confirms that the security analysis of CV-MDI-QKD must generally involve a careful minimization over two-mode attacks as originally performed in (Pirandola et al, 2015 Nature Photon.
9, 397–402; arXiv:1312.4104 (2013)).
Apical Constriction Reversal upon Mitotic Entry Underlies Different Morphogenetic Outcomes of Cell Division
Authors: Ko Clint S. , Kalakuntla Prateek , Martin Adam C.
Published: July 2020

Cell divisions can either promote or inhibit tissue morphogenesis. In contractile epithelia, mitotic entry disrupts medioapical myosin activation and reverses apical constriction. We found that different spatiotemporal patterns of mitotic entry and the resultant changes in force generation at the tissue level dictate distinct tissue shape outcomes.
The Moderating Effects of Social Support and Stress on Physical Activity in African American Women
Authors: Brown Asia , Wilson Dawn K , Sweeney Allison M , Van Horn M Lee
Published: July 2020

Background

African American women participate in less physical activity (PA), have higher rates of chronic disease, and report higher perceived stress relative to other race and sex demographic groups.

Purpose

Based on the stress-buffering hypothesis, this study tested the hypothesis that social support would buffer the negative effects of perceived stress on moderate-to-vigorous PA (MVPA) under high, but not low, perceived stress.

Methods

Participants were 143 African American women (mean [M] age = 43.94, standard deviation [SD] = 8.62; M body mass index = 37.94, SD = 8.11) enrolled in the Families Improving Together (FIT) for Weight Loss Trial. Average daily minutes of MVPA were obtained via 7 day accelerometer estimates at baseline and 8 and 16 weeks.

Results

A multilevel growth model demonstrated a significant three-way interaction between stress, social support, and time (B = −0.31, standard error [SE] = 0.14, p = .03). Simple slopes analyses revealed that, at baseline, among participants with high social support (+1 SD), stress was positively associated with greater MVPA (B = 0.49, SE = 0.18, p = .008), whereas among participants with low social support (−1 SD), stress was not significantly associated with MVPA (B = −0.04, SE = 0.14, p = .81). However, at 8 and 16 weeks, stress was not significantly associated with MVPA for either high or low support groups.

Conclusions

Findings highlight the importance of integrating constructs of stress and social support into future physical activity intervention programs for African American women and the need to evaluate changes in stress and social support longitudinally.
Exploratory Validation Study of the Individual AUDIT-C Items among Older People
Authors: Stewart Duncan , Hewitt Catherine , McCambridge Jim
Published: July 2020

Aims

The AUDIT-C is a brief and commonly used alcohol screening tool, with few data available on the relative validity of the three individual items in older adult populations. The aim of this study was to explore the validity of the AUDIT-C items in identifying unhealthy drinking among older people, with a view to developing a single-item screener.

Methods

A sample of 143 older adults (mean age = 71) were recruited from non-clinical settings in the UK. AUDIT-C scores were compared to an unhealthy drinking reference category of consuming more than the UK recommended weekly units of alcohol. Standard analyses were conducted for men and women, and for those prescribed medications for long term conditions.

Results

The AUDIT-C items performed well in identifying unhealthy drinking in this sample of older people, with generally high sensitivity, specificity and area under the ROC curve. No significant differences were found in the validity of the three items, though the combined sensitivity and specificity scores and ROC values for item 3 were consistently slightly lower than for items 1 and 2. The findings were similar for men and women, and for participants prescribed medications for long-term conditions.

Conclusions

AUDIT-C items 1 and 2 performed as well as item 3 in identifying unhealthy drinking among older people in this study. Both are reasonable single-item screener candidates, especially given relative ease of administration, with further validation study needed to examine psychometrics and how alcohol screening for older people can best be implemented in clinical settings.
treeheatr: an R package for interpretable decision tree visualizations
Authors: Le Trang T , Moore Jason H
Published: July 2020

treeheatr is an R package for creating interpretable decision tree visualizations with the data represented as a heatmap at the tree’s leaf nodes. The integrated presentation of the tree structure along with an overview of the data efficiently illustrates how the tree nodes split up the feature space and how well the tree model performs. This visualization can also be examined in depth to uncover the correlation structure in the data and importance of each feature in predicting the outcome. Implemented in an easily installed package with a detailed vignette, treeheatr can be a useful teaching tool to enhance students’ understanding of a simple decision tree model before diving into more complex tree-based machine learning methods.

Availability and implementation

The treeheatr package is freely available under the permissive MIT license at https://trang1618.github.io/treeheatr and https://cran.r-project.org/package=treeheatr. It comes with a detailed vignette that is automatically built with GitHub Actions continuous integration.
MUC1-C in chronic inflammation and carcinogenesis; emergence as a target for cancer treatment
Authors: Kufe Donald W
Published: July 2020

Chronic inflammation is a highly prevalent consequence of changes in environmental and lifestyle factors that contribute to the development of cancer. The basis for this critical association has largely remained unclear. The MUC1 gene evolved in mammals to protect epithelia from the external environment. The MUC1-C subunit promotes responses found in wound healing and cancer. MUC1-C induces EMT, epigenetic reprogramming, dedifferentiation and pluripotency factor expression, which when prolonged in chronic inflammation promote cancer progression. As discussed in this review, MUC1-C also drives drug resistance and immune evasion, and is an important target for cancer therapeutics now under development.
Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals
Authors: Keogh Mandy J , Gastaldi Angela , Charapata Patrick , Melin Sharon , Fadely Brian S
Published: July 2020

Assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. Hair is increasingly being used to investigate stress-related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. We validated enzyme immunoassays for measuring aldosterone, cortisol, corticosterone, and testosterone in lanugo (natal hair grown in utero) samples collected from Steller sea lions (Eumetopias jubatus), California sea lions (Zalophus californianus), and northern fur seals (Callorhinus ursinus). We applied laboratory validation methods including recovery of added mass, parallelism and dilution linearity. We found no effects due to differences in alcohol- versus detergent-based cleaning methods. Further, there were no significant differences in hormone concentrations in hair samples collected immediately after the molt and the subsequent samples collected over 1 year, indicating steroid hormones are stable once deposited into pinniped hair. We found no sex differences in any hormone concentrations, likely due to the lanugo being grown in utero and influenced by maternal hormone concentrations. For Steller sea lion and California sea lion pups, we found hormone concentrations significantly differed between rookeries, which warrants future research. Hair provides a novel tissue to explore the intrinsic or extrinsic drivers behind hormone measurements in otariids, which can be paired with multiple health-related metrics to further investigate possible drivers of physiological stress.
Extensive right atrial free wall low-voltage zone as the substrate for atrial fibrillation: successful ablation by scar homogenization
Authors: Al-Kaisey Ahmed M , Parameswaran Ramanathan , Joseph Stephen A , Kistler Peter M , Morton Joseph B , Kalman Jonathan M
Published: July 2020

Aims

Prior studies have described a variety of mechanisms for atrial fibrillation (AF) originating in the right atrium (RA). In this study, we report a series of patients in whom an extensive right atrial free wall low-voltage zone (LVZ) served as the AF substrate.

Methods and results

Five patients with a clinical syndrome of paroxysmal AF and atrial tachycardia (AT) underwent electrophysiologic evaluation. Five patients (3 M; age 52 ± 7 years) had symptomatic paroxysmal AF for (28 ± 17 months) not responsive to medical therapy. At the initial EP study, AT was inducible in four patients and was spontaneous in one patient. In all patients, tachycardia instability precluded detailed AT mapping. Sinus or pace maps indicated an extensive LVZ in the lateral RA trabeculated free wall which consisted of regions of low amplitude complex signals interspersed between electrically silent areas. Radiofrequency ablation aimed at rendering the LVZ electrical inert was successful in eliminating AF in four of five patients. At a follow-up of 28 ± 15 months, one patient had an isolated recurrence of AF. However, two patients required repeat ablation for recurrent AT.

Conclusion

An extensive LVZ in the trabeculated RA free wall constitutes an unusual substrate for AF. These patients also demonstrate unstable ATs originating from the same zone. Radiofrequency ablation to render the low-voltage zone electrically inert is an effective strategy to manage AF and AT.