bluuebunny/crossref_metadata_2025 huggingface dataset:
The research of post-treatment on Cd1-xMgxTe thin films and CdTe solar cells
Authors: Feng Ye , Yu Mingzhe , Huang Jian , Hao Xia , Li Wei , Zhang Jingquan , Wu Lili
Published: August 2019

As for it higher band gap, Cd1-xMgxTe (CMT) material has been taken into consideration to improve the open-circuit voltage of CdTe solar cells as an electron reflector layer. An essential step in the development of this new interlayer is the passivation process. X-ray Diffraction (XRD) and scanning electron microscope (SEM) results give us the suitable annealing temperature range of CMT thin films from 350°C to 400°C, and suggest that the annealing process is beneficial to grain growth and recrystallization. The concentration of CdCl2 solution has an influence on the crystallinity of the thin films and coating method would contribute to electrical performance of the devices. The CMT/CdTe cells which underwent the two-step annealing procedure at high purity nitrogen atmosphere showed the significant improvements in device performance. Furthermore, the CdTe solar cells with the CdTe cap layer and Te/Cu back contacts also demonstrated higher performance.
Optical design and experiment evaluation of a novel asymmetric compound parabolic concentrator (ACPC) integration with PV for building south wall application
Authors: Xuan Q , Li G , Pei G , Lu Y , Su Y , Ji J
Published: August 2019

Compound parabolic concentrator (CPC) as a typical low-concentration-ratio concentrator is an interesting topic for it can work as the static concentrator without any additional tracking systems or seasonal adjustments, which shows a promising concept of introducing the concentrating PV technology for building application. Therefore, based on the compound parabolic curves, a novel asymmetric compound parabolic concentrator (ACPC) is proposed in this paper for building south wall integration. The optical model of the ACPC is built by the software Lighttools to study its optical performance, and the structure parameters of it are optimized through the optical simulation. Then the prototype of the ACPC integrated with the PV cell as the ACpC-PV module is manufactured and assembled. The indoor experiments by the solar simulator (Oriel Sol3A Model 90943A) from the Newport Corporation at the dark environment with the temperature of 25 °C are conducted to study the electrical performance of the ACPC-PV module. The simulation and experiment results show that the acceptance range of the ACPC with the geometric concentration ratio of 2.4X can be 65° with high optical efficiency. A good agreement is observed between the simulation and experiment results despite the deviation of around 13% which is inevitable due to all kinds of errors, such as manufacturing errors, mismatch losses, series resistance losses, etc.
Airflow Organization in a Transformable Shelter
Authors: Guo Liang , Ye Hong
Published: August 2019

The environmental control system of a shelter can provide comfortable temperature, air velocity and fresh air supply for members indoor, protecting them from the extreme weathers or oxygen-poor environment in the field. A shelter with transformable walls will have a large available space including the core module and extended modules for diverse demands such as dining or sleeping. The airflows in such a limited space can be inevitably influenced by walls and furniture. In the study, a transformable shelter with top supply and bottom return air organization mode was taken as the research object. The air supply duct on the ceiling of the shelter was designed to uniform the supplying air quantity through each outlet by adding baffles in the duct. Baffles can also make the export winds nearly perpendicular to the duct wall. The indoor airflow velocity and temperature fields in the condition of people gathering for dinner were obtained by simulation, so as that in the condition of people scattering for sleeping. In the dining condition, the barriers to the uniform airflow and temperature are the crowd occupying the core module. In the sleeping condition, the dominating barriers are the walls between different modules. The airflows were uniformed between different modules by opening apertures across the partitions. In view of human comfort, a comprehensive evaluation of the air flow organization was given, which presents an essential reference for system design and optimization.
Preliminary analysis of supercritical CO2 Brayton cycle applied to the solar thermal plant
Authors: Sun L , Xie YH , Zhang D
Published: August 2019

The use of a highly compacted and efficient supercritical CO2 (S-CO2) Brayton cycle has become an effective way in utilizing solar energy. This work performs a comprehensive parametric study for S-CO2 Brayton cycle applied to the solar thermal plant. Several different power cycle layouts including basic regenerative cycle, recompression cycle, intercool cycle and reheat cycle are analysed by the computational models consist of various components in this paper. Then, the optimization of parameters including the cycle turbine inlet temperature and so on, is also performed based on genetic algorithm to achieve the best cycle performance. The most promising cycle configuration is selected by comparison of the compromise between cycle and recuperator performance. This study provides some reference for the related research of the S-CO2 Brayton cycle integrated with solar thermal systems.
Analysis of Point Daylight Factor (PDF) Average Daylight Factor (ADF) and Vertical Daylight Factor (VDF) under various unobstructed CIE Standard Skies
Authors: W Li Danny H , Li Shuyang , Chen Wenqiang , Lou Siwei
Published: August 2019

The usual method for computing natural illuminance for a given location in a building is the daylight factor (DF) approach, which is based on the traditional overcast sky without sunlight, as defined by the International Commission on Illumination (CIE). In 2003, the CIE adopted a range of 15 skies as international standard models that represent the actual skies of many places and cover the whole probable spectrum of skies found in nature. Previously, we developed a number of calculation tools to predict daylight illuminance for rooms facing different orientations under various CIE Standard skies. This paper presents the work on the calculation of the point DF (PDF), average DF (ADF) and vertical DF (VDF) under various overcast and non-overcast skies. The strong correlations between these three DF types can help to estimate the required DF values for architectural and daylighting designs and evaluations.
A smart hybrid pole with street lighting and EV charging based on DC micro-grid and renewable energy
Authors: Zhang Yongming , Li Li , Yan Zhe , Yao Jiawei
Published: August 2019

In order to efficiently utilize renewable energy and solve roadside fast charging of Electric Vehicle (EV) problem, a smart hybrid pole system is proposed in this paper, which integrated with renewable energy Street Lighting Pole (SLP) and EV charging. Besides, smart hybrid pole can also serve as the backup power for traffic lights. In this system, several renewable energy SLPs are coupled together by Direct Current (DC) micro-grid with storage battery, so it is suis for both DC fast charging and slow charging for EV. More importantly, the energy efficiency in this system can become much higher than alternating current (AC) EV charging system, because renewable energy power such as photovoltaic (PV), load and energy storage are all DC subsystem. Then for studying the suitable number in a group of smart hybrid pole, the group model of smart hybrid pole is presented. In addition, the hybrid pole energy storage system can be controlled by a cloud management platform, so it is convenient to make the decision to charge or discharge according to the different power prices. The smart hybrid pole solution is conducive to EV charging and the efficient application of renewable.
The relative change of drying rate as a function of the cumulative ventilation air drying potential in a thin-layer solar drying facility
Authors: Krawczyk P
Published: August 2019

Controlling low-temperature drying facilities which utilise non-prepared air is quite difficult, due to very large variability of ventilation air parameters – both in daily and seasonal cycles. The results of experimental studies of sewage sludge solar drying process in thin-layer solar dryer have been presented. It was found that regardless of weather conditions, the rate of sewage sludge drying is significantly changed during drying process. The results showed that the rate of drying decreases with increasing so called cumulative ventilation air drying potential.Knowledge on current dryin rate provides new possibilities for controlling such systems. Based on the results, operating recommendations for analysed type of dryer have been formulated.

Experimental data analysed in the paper was collected in 2012 - 2014 during operation of a test solar drying facility in a sewage treatment plant in Błonie near Warsaw, Poland.
Steady-Flow-Type Particle Receiver for High-Temperature Solar Thermal Storage
Authors: Matsubara Koji , Suzuki Yudai , Sakurai Atsushi , Bellan Selvan , Kodama Tatsuya
Published: August 2019

The concentrated solar power is utilized for industrial thermal usage, electricity generation and fuel production. To increase the solar thermal temperature is essential for enhancing the thermal efficiency of the energy conversion and for widening application. The synthetic oil, widely used for solar thermal storage, pylorizes at 400 °C, and this cannot be used for very high temperatures. The authors used quartz sand as thermal storage medium in the fluidized bed receiver, and achieved the thermal receiver temperatures beyond 1000 °C in the previous report. The research work was further made on using the particle steady flow for high-temperature solar thermal storage. The steady-flow-type particle receiver was designed through visualization of cold model and numerical simulation. The experimental apparatus was fabricated and tested using beam-down sun simulator of 1.0 kWth. The apparatus comprises of the internal-circulating fluidized bed receiver placed between a loop seal with an inlet port and another loop seal with a weir and an exit port of the particles. The tested particles are quartz sand of 0.1 – 0.2 mm and fused brown alumina of 0.09 – 0.1 mm. The experimental set up produces hot particles of quartz sand at 428°C and those of fused brown alumina at 491°C. The highly efficient steady-flow-type particle receiver created steady particle flow smoothly. This apparatus takes in the concentrated light through the quartz window to continuously discharge the particles at high temperatures beyond the criterion in synthesis oil (400°) for solar thermal storage.
Direct Simulation of Volumetric Solar Receiver with Highly Concentrated Radiation
Authors: Nakakura Mitsuho , Matsubara Koji , Bellan Selvan , Kodama Tatsuya
Published: August 2019

The volumetric solar receiver is a promised technology for high-temperature solar absorption in the concentrated solar power, industrial solar thermal usage and solar fuel production. Existing numerical simulation separated computations of light and convective flow and two-way coupling was not perfectly integrated between radiation and convective transport. This paper describes conjugate analysis of radiation, convection and conduction heat transfer in the volumetric receiver for perfect three-way coupling between three mechanisms of heat transfer. The numerical scheme was used for the volumetric receiver with plane surface and that with cut-back inlets for optimization of the geometry. The simulation was made for single cell of honeycomb with 2.4 mm pitch and 0.5 mm wall thickness. Two cases of surface geometry was computed: plane surface; cut-back inlet with 10 mm depth. Basic equations are momentum and energy equations with radiation transport equation. The discrete ordinates method was applied for solving the radiation intensity to consider perfect interaction between radiation, convection and conduction. The material of the receivers are assumed as stainless steel. The numerical simulation demonstrated the superiority of the cut-back receiver which increased the exit temperature by 30 K and decreased 2 Pa for the smallest beam angle of 10°. The contour plot of total heat flux on the wall revealed that the shadow effect was attenuated by the cut-back inlet leading to heat transfer enhancement. The novelties of this work are to treat perfect interaction between radiation and convection in volumetric receiver and to demonstrate the excellence of cut-back inlet receivers.
Performance Simulation for Gas Flow through a Porous Media in Packed bed Columns using CFD
Authors: Salim Bded Asaad
Published: August 2019

Two dimensions of Computational Fluid Dynamics simulation for gas flow in the column with filling material as bed at low particle Reynolds numbers and high particle Reynolds numbers have been presented. The simulation test has been done with the column length 0.9 m. Porous media model was used to simulate the gas flow inside porous granular media. Model of standard k-e for the flow turbulent range was used; the difference on the mesh size used to study effect it on the performance of gas flow through porous media. The result of flow rate of the gas was an important variable influencing bed and there are good results between the CFD simulation of pressure drop and the predicted values from Ergun model, and Computational Fluid Dynamics gave us simulation with high details for porous flow in packed bed equipment.
Experimental Study on Tanuma Shale Stability Using Drilling Fluids with Different Additives
Authors: Mohammed Khalid , Alwassiti Asawer A. , Ali Al-Bidry Mayssaa
Published: August 2019

Shale formation is represented as one of the challenge formations during drilling wells because it is a strong potential for wellbore instability. Tanuma formation in Iraqi oil fields (North Rumila) is located at a depth from 2102 m MD – 2126 m MD. It is considered one of the most problematic formations through drilling wells in North Rumila. Most problems of Tanuma shale are sloughing, swelling, caving, cementing problem and casing landing problem caused by the interaction of drilling fluid with the formation. This paper focuses on studying the chemical and minerals properties of Tanuma shale. In addition, study the effect of drilling fluids and additive salts by using different techniques; (XRD, XRF, reflected and transmitted microscope, scanning electron microscope and EDS)Also, the study includes experiments to observe and enhance the shale stability by using two types of drilling fluids, API and polymer type, with different additives. Four types of additives (KCl, NaCl, CaCl2 and Sodium silicate) in different concentrations (0.5, 1, 5 and 10) wt % and different immersion period (1, 24 and 72 hours) were used. The results show that adding 10 wt. % of sodium silicate to API drilling fluid results in a high percentage of shale recovery (77.99%). While, the maximum shale recovery was (79.76%) in polymer drilling fluid type gained by adding 10 wt % of sodium silicate.
Improving Drilling Fluid Properties at High Pressure Conditions Using Selected Nanomaterials
Authors: Sabah Nada , Alswasiti Asawer A. , Salam Massara
Published: August 2019

Drilling fluids with conventional lubricants (including solid and liquid lubricants) will produce lubricant film between drill string and wellbore/casing, but this film will not be strong enough to protect the bit bearing surfaces subjected to high load conditions during the drilling operations, resulting in shortening the life of drill bit. In this research, the possibility of using nanomaterials as extreme pressure lubricants was investigated by adding different concentrations (0.02, 0.05 and 0.1) wt. %of TiO2nanoparticles (NPs) and Cu NP into water- based mud. The lubricating film strength of water based mud samples under extreme pressure conditions were measured using Extreme Pressure (EP) and Lubricity Tester. With the purpose of getting the best performance from extreme pressure lubricants, the effect of nanomaterials on rheological (including plastic viscosity, yield point, apparent viscosity, and gel strength) and filtration (including filtrate loss volume and mud cake thickness) properties were measured. TiO2 NPs and Cu NP showed a good enhancement in lubricating film strength under extreme pressure conditions. The maximum value of lubricating film strength increasing percentage (69.6%) was obtained using TiO2 NPs with concentration of 0.1wt.%.
Modeling and simulation of adsorption of methane, ethane, hydrogen sulfide and water from natural gas in (FP)YEu Metal–Organic Framework
Authors: Al-Jadir Thaer M. , Siperstein Flor R.
Published: August 2019

Metal Organic Frameworks (MOFs) are novel type of hybrid porous materials that have been proposed for natural gas separation and purification due to the possibility of tailoring their capabilities by changing the organic linkers, tuning the length of the organic linker and changing or mixing the metal ion. Molecular simulation helps to understand experimental results by providing a detailed picture on the molecular scale that is not easily accessible from experimental and can be used to study the applicability of classical force fields.

In this work, FPYEu MOF [1] [2] was carefully chosen as an example of a model MOF for studying applicability of force fields, cutoff radius besides the effect of different distributions of metal ions in FPYEu MOF on adsorption of CH4, C2H6, H2S as well as H2O.

Grand Canonical Monte Carlo (GCMC) simulations were used to perform gases adsorption on FPYEu MOF cells containing different distributions of Yttrium and Europium. All simulations in this work have been carried out using Towhee code [3].

The applicability of different force fields available in the literature was tested and some of them were applicable like H2S, where good agreement was found with experimental results, while others were not applicable, like CH4, C2H6 and H2O, where the calculated isotherms “over or under” estimated the experimental ones. In addition, eight different configurations having Eu atoms arbitrarily located in the system were explored to evaluate the sensitivity of distribution of metal ions.
Calculating heterogeneity of Majnoon Field/Hartha Reservoir using Lorenz Coefficient method
Authors: Al-Joumaa J H , Al-Jawad M S
Published: August 2019

One of the principle concepts to understand any hydrocarbon field is the heterogeneity scale; This becomes particularly challenging in supergiant oil fields with medium to low lateral connectivity and carbonate reservoir rocks.

The main objectives of this study is to quantify the value of the heterogeneity for any well in question, and propagate it to the full reservoir. This is a quite useful specifically prior to conducting detailed water flooding or full field development studies and work, in order to be prepared for a proper design and exploitation requirements that fit with the level of heterogeneity of this formation.

The main tool used for these purposes is the application of the famous Lorenz coefficient method for calculating the degree of heterogeneity for any well. The starting point for this kind of complicated studies needs to start from the basics, in order to understand the big picture and be able to plan properly for the scope to be delivered, hence, utilizing analytical tools like the ones mentioned above becomes quite necessary, if not crucial, to the success of full field modelling and choosing an optimum water flood pattern and design.

This paper covers the methodology for quantifying and calculating the level of heterogeneity in a given reservoir (Majnoon Field/Hartha Reservoir) using three out of four original wells of this reservoir, and how this value impacts and directly feeds into planning for water flooding projects and selection of an optimum flood pattern.

This methodology has been tested successfully in the stated super giant oil field, in which the reservoir in question is a carbonate rock formation. It is important to note that the chosen reservoir is giant areally with moderate thickness. An example of this is covered in the paper. It was concluded that utilizing a heterogeneity calculation method before conducting a detailed reservoir simulation study can save a lot of time and effort by providing guidance to the path which needs to be followed, and sheds light on the critical elements to be looked after. This has also helped to uncover many insights on the reservoir itself, hence allowing the engineer to plan for the necessary voidage replacement and water injection rates to sustain the reservoir pressure and pattern development.

The suggested method, in combination with geological and petro physical information available, can be applied to majority of the reservoirs. This combination is paramount to ensure optimum time and planning is followed for each reservoir development study that involves water flooding.
Enhanced Recovery of Heavy Oil Using A Catalytic Process
Authors: Hasan M M , Rigby S P
Published: August 2019

Oil is a major source of energy around the world. With the decline of light conventional oil, more attention is being paid to heavy oil and bitumen, as a good alternative to light oil for energy supplies. Heavy crude oils have a tendency to have a higher concentration of metals and several other elements such as sulfur and nitrogen, and extraction of these heavy oils requires more effort and cost. Toe-to-Heel Air Injection (THAI) is a novel process of enhanced heavy oil and bitumen recovery and upgrading. In this technique, horizontal well concepts are integrated with the reactions of high temperature oxidation to achieve a potentially high recovery ratio. Since the process works through a short distance displacement technique, the produced oil flows easily toward the horizontal producer well. This direct mobilized oil production and short distance are the major features of this method which lead to robust operational stability and high oil recovery. This technique gives the possibility of a higher recovery percentage and lowers environmental effects compared to other technologies like steam based techniques. A novel well design consisting of two horizontal injectors and two horizontal producers was used in different well configurations, to investigate the potential for improved efficiency of the THAI process on the heavy oil recovery. A 3D dimensional model, employing the CMG-STARS simulator, was applied for this process. Two horizontal injectors and producers were utilised in this project, instead of the conventional horizontal injector and producer used in the Greaves model (the base case model), to investigate the effect of the extra injector and producer on the performance of the THAI process. It was found that the locations of the well injections and the well productions significantly affected the oil production. It was found that the amount of the produced oil rose up to about double of the amount of the oil produced by the original model. For the study of the effectiveness of the catalysts in the oil upgrading process, the CAPRI technique has been simulated to investigate the effect of several parameters, such as catalyst packing porosity, the thickness of the catalyst layer and hydrogen to air ratio, on the performance of the CAPRI process. The TC3 model used by Rabiu Ado [1], which was the same model utilised in the experimental study of Greaves et al. [2], was also employed in this study. The silica-alumina catalyst characterised by Hasan [3] was placed around the horizontal producer in this simulation.
Identifying hydrocarbon and shaly zones of Mishrif Formation in Nasiriya Oil Field by using well logs
Authors: Hameed Ameer T. , Aldabaj AbdulAali A. , Ramadhan Ahmad A.
Published: August 2019

Well logging is the process of recording physical, chemical, electrical and other properties of rock/fluid mixture penetrated by drilling a borehole into the earth crust. Many of these logs are electrical in measurements. Hydrocarbon may exist in a porous and clean formation. That is, gamma ray and spontaneous potential can identify shaly/clean zones while neutron, density, sonic logs or even NMR logs may be used for porosity estimation. Resistivity logging is used to differentiate between formation filled with salty water (low resistivity) and with those filled with hydrocarbons (high resistivity). Mishrif Formation in Nasiriya Oil Field was chosen as a case study. The Nasiriya oil field structure is an anticline with NW- SE trend. Mishrif Formation is the Majer middle cretaceous carbonate in the stratigraphic column of southern Iraq. The result of well logs interpretation for the first five wells showed that a shaly unit separate upper Mishrif (MA) from the lower one (MB). Also, both units MB1 and MB21 are considered the movable hydrocarbon zones. The CPI data reflect that in which good values of porosity of about 0.18 in unit MB1 and 0.2 in unit MB21, besides low values of water saturation 0.28, 0.45 in units MB1& Mb21, respectively.
Improving the Properties of Acrylic by Creating Crack Using Laser Beam
Authors: Hwayyin R N , Hammood A S
Published: August 2019

The study investigates the improvement of the mechanical properties of the acrylic layer by creating a crack according to polynomial’s function by using the CO2- laser and without additives. The cracks were created by the laser at different powers and different speeds. The shape of the cracks was created according to six degree polynomial’s function by using CNC-laser machine. The study focused on the effects of creating an edge on both sides of the crack generated from the laser heat helping to change the microstructure on it to resist the failure crack growth. The study adopts a laser beam path according to equation g(x) to show the effect of the shape of the laser beam on improving the properties of the acrylic specimens. The experimental results have shown the effect of laser beam speed and laser beam power on the stress-strain. The experimental results shown increasing in the stress with average rate (12.25%) due to increasing laser beam power at (40, 50 and 60). The experimental results of specimens type (O and A4) shown improving in the stress at average rate (12.87%) and copmaring the experimental results of specimens type ( O, A5 and A6) has revealed an incresing in the tensile stress with average rate (14.088%).
Response of Soft Soil Mixing with Recycled Gypsum (Plasterboard) as Stabilized Agent for Soil underneath oil tank as a case study
Authors: Al-Adili A , Salim N M , Al-Soudany K. Y.
Published: August 2019

Soil stability plays a vital rule in projects’ infrastructure such as embankment, retaining walls dams and highway. Structure built on soft soil may experience uncontrollable settlement and critical bearing capacity. This may not meet the design requirements for the geotechnical engineers. Soil stabilization is a process to change such undesirable properties in order to meet the requirements. The main objective of this study is to evaluate the use of recycled gypsum, which is derived from gypsum waste plasterboard, as a stabilized agent for soft clay. Twenty eight experimental tests have been conducted to improve a soil brought from a site in Basra (Garma Ali/south of Iraq) using four different recycled gypsum percentage varying from 0 to 15%. The properties which have been studied are grain size distribution, Atterberg limits, unconfined compressive strength, and compressibility. The results indicate that as the gypsum contents increase, the liquid limit decreases up to gypsum content of 3% and then increases. The plastic limit has been decrease up to 7 % of the gypsum content and then increases. Furthermore, the maximum dry density decreases while the optimum moisture content is increased as the percentage of gypsum content has increased. The compression index (Cc
) has increased as the gypsum content increases while the swelling index has increased up to 5% then it has decreased. The unconfined compressive strength has increased by adding recycled gypsum up to 5% while it is reduced as the percentages of gypsum has increased beyond 5%. Adding 5% of recycled gypsum raise the bearing capacity to approximately 167% compared with the bearing capacity of untreated one.
Linear and Non-Linear Stress Analysis for the Prediction of Fracture Toughness for Brittle and Ductile Material using ASTM E399 and ASTM E1290 By ANSYS Program package
Authors: Nassar A A , Fayyad E G
Published: August 2019

Prediction of fracture toughness value of most the metallic materials is a very important issue to be consider in designing of engineering structural components like pipes, flow tanks and pressure vessel where it can be used in the evaluation of critical crack length that is consider very important factor in non-destructive testing because during inspections of these components, the critical crack length is being compared with the minimum allowable flow size. Fracture toughness value can be predicted by using two different types of experimental tests such as ASTM-E399 (which is used to predict fracture toughness under plane strain condition for brittle materials which undergo to small plastic deformation) and ASTM-E1290 (which is used to predict fracture toughness for ductile materials which undergo to large plastic deformation). These experimental tests utilize specimens such as compact tension specimen CT and three-point bend specimen SENB which must be pre-cracked. However, manufacturing of pre-cracked in metallic structural components before testing is expensive and time-consuming process, thus in the current study, fracture toughness will be predicted by using economized method in both time and cost that is the finite elements method by using ANSYS PROGRAM Where, a three-dimensional model has been designed by using two different types of elements (plane-82) and (solid-95).Firstly, two-dimensional model mesh will be idealized by using element type (plane-82) due to ANSYSY PROGRAM can pick–up singularity for two dimensional model only, but in order to obtain more accurate results, a three dimensional model will be designed by utilizing Sweep Model with restriction with ANSYSY abilities in the treatment of fracture mechanics problems for three dimensional model analysis where the element length must be ranging from 1to4 in all directions. In elastic region, the fracture toughness is been predicted directly from ANSAYS PROGRAM using the specification in ASTM-E-399 for compact tension specimen for practical design problems. But in elastic-plastic region, the fracture toughness is been predicted by using the crack tip opening displacement model (CTOD-Model) using the specification in ASTM-E-1290 for three-point bend specimen for practical design problem. The critical value for crack tip opening displacement will be calculated after extracting load-displacement data from ANSAYS PROGRAM then using these data in (CTOD-Model) which is separated into two components, elastic and plastic, the elastic component has been estimated using Dug Dual-Model, while the plastic component will be estimated using Plastic Hinge-Model. However, the fracture toughness value that has been predicted by finite element method from non –linear elastic analyses and from non –linear elastic-plastic analyses gives excellent results which are very close to the experimental results with error ratio ranging between (10% to 14%).
Optimization of Liquid Rocket propulsion system for Reusable Orbital Transfer Vehicle
Authors: Borovik I , Borovikov D , Protopopov A
Published: August 2019

The work is devoted to the investigation of possible ways to increase the efficiency of reusable orbital transfer vehicle (R-OTV) by using a multi-criteria optimization procedure of liquid rocket propulsion system (LRPS) design parameters. The “Federation” spacecraft is considered as an example payload of R-OTV for orbital transfer mathematical modeling, due to its known initial mass of 16,500 kg and other design parameters. Payload mass and specific cost of payload transfer are chosen as optimality criteria.

Multiple tasks are solved during the work: mathematical model and corresponding software for determining the optimal design parameters of R-OTV LRPS by mass and cost criteria are developed, R-OTV and LRPS calculation and optimization are conducted, the technical appearance of LRPS is designed.

Mathematical modeling is used to solve the presented problem. A developed mathematical model has a modular structure, in particular, it has modules for liquid rocket engine (LRE) mass calculating, OTV (Orbital Transfer Vehicle) mass calculating module, payload mass, design cost and manufacturing cost calculating modules for LRE and OTV and module for calculating the specific cost of payload transfer to target orbit. The intermediate result is used by LRPS project parameters design optimization module, then by technical appearance design module and LRPS units design module.

Multiple calculations are conducted with a developed mathematical model. Verification of the model is carried out by developing the technical appearance of real OTVLRPS. Several variants of LRPS for spacecraft “Federation” type OTV are designed for low lunar orbit, OTV parameters are compared with optimized LRPS and with existing LRPS.
Manufacturing technology stamp-welded workpieces based on porous-net material with desired properties
Authors: Tretiakov A , Serezhkin M
Published: August 2019

The manufacture of stamp-welded and porous elements of porous-net material (PNM) from stainless steel 12H18N10T (0,12% C, 18% Cr, 10% Ni, 1% Ti) is difficult due to the low ductility under tension and the lack of weldability. It limits the use of PNM, although the fact that they may have the necessary technological and operational properties. The effect of porosity and heat conductivity anisotropy on the strength of welded splices of parts made of PNM have been established. Technologies of electron-beam welding (EBW) and sheet stamping of filter elements, which are implemented during the manufacture of prototypes of filter elements with a cleaning precision 10-12 microns, are presented.
Phytochemical Analysis of Mangrove Leaves (Rhizophora sp.)
Authors: Syahidah  , Subekti N
Published: August 2019

Mangrove plants have been reported as resources of many traditional folk of medicine and contain several kinds of trace elements which are being used to treat diseases. The aim of this study was to analyzed the phytochemical compounds of mangrove leaves. Our previous studies showed that the extract of mangrove leaves tend to be polar. The acetone and methanol extract of the mangrove leaves had high anti termite and antifungal activity. Based on this information, phytochemical content of mangrove leaves have been analyzed to find out the chemical substances that responsible for the bioactivity properties. Folin-Ciocalteu method was used to quantify the total phenolic content using a calibration curve of gallic acid, while for phytochemical were analyzed using spectrofotometric method. The results showed that the acetone extract of mangrove leaves containing alkaloid, polyphenolic, flavonoid, and total tannin higher than the methanol extract. This data will be further analyzed to obtain the compounds that may responsible for the biological performance of mangrove leaves.
Effect of CO2 on the degradation of cement-bonded particleboard based on the treatment to conventional cured board
Authors: Maail R S
Published: August 2019

This study aimed to evaluate and clarify the effect of CO2 at either the gaseous or supercritical phase on the degradation of cement-bonded particleboard (CBP) based on the treatment to conventional cured board, while the estimation of long term degradation of CBP is also discussed. The properties of CBP are improved by CO2 treatment in short period in both the gaseous and supercritical phases even after the conventional curing process. These properties, however, over the longer treatment time degraded in rapid rate against CO2 treatment in both the gaseous and supercritical phases. It was considered that the degradation of CBP increased with increasing the CO2 concentration, CO2 pressure and treatment time. With the longer treatment time against supercritical CO2 in higher concentration and pressure, the residual values of mechanical properties (IB strength, MOR, and MOE) were decreased, indicating CBP performance was degraded rapidly compared to treatment in the lower concentration and pressure of CO2 or under gaseous phase. High coefficient determination values between the residual values of CBP properties, and the treatment time and CO2 concentration were observed and the simple linear model was found to estimate the long term degradation of CBP among the properties and affecting factors.
The Formulation of Apis mellifera L. Honeybees Feed Making as Pollen Subtitute on Poor Season
Authors: Budiaman  , Saleh M , Yusran  , Paembonan S A , Gautama I , Sanusi D , Millang S
Published: August 2019

The Apis mellifera honey bees is one of the most cultured species in Indonesia, both by ordinary people, government (Perum Perhutani and Forest Service) as well as private companies that are managed in a modern way. This research aims to find out the best artificial feed formulation for Apis mellifera hone bees. This research used randomized block design with 4 treatments and 3 replications. The treatment is as follows: Treatment A: Soybean flour + sugar syrup, Treatment B: Dried peanut flour + sugar syrup, C: Peanut flour + sugar syrup, Controls: Natural pollen in flour form. The data obtained were analyzed by Randomized Block Design Equation.

The results showed that the type of pollen substitute TKH and natural pollen is the best feed to increase the growth of Apis mellifera L. bee seedlings in terms of the increase of consumption level and the extent of saplings.
Quantum walk as generalized evolution and measurement device
Authors: Zhan Xiang
Published: August 2019

We show that arbitrary quantum evolution, both unitary and non-unitary ones, can be efficiently realized via one-dimensional quantum walk. This is done based on the equivalence between quantum evolution and positive-operated valued measurements, and an algorithm of properly controlling one-dimensional discrete-time quantum walk to realize arbitrary positive-operated valued measurements. Furthermore, our method based on one-dimensional quantum walk can be easily generalized to other platforms Our method enriches technics for quantum information processes, and the applications of quantum walk.
Improving performance of an analog electronic device using quantum error correction
Authors: Ostrove Corey , Cour Brian La , Lanham Andrew , Ott Granville
Published: August 2019

The use of analog classical systems for computation is generally thought to be a difficult proposition due to the susceptibility of these devices to noise and the lack of a clear framework for achieving fault-tolerance. We present experimental results for the application of quantum error correction (QEC) techniques to a prototype analog computational device called a quantum emulation device. It is shown that for the gates tested (transversal Z, X and SH) there is a marked improvement in the performance characteristics of the gate operations following error correction using the 5-Qubit Perfect code. In the case of the Z gate, the median fidelity improved from 0.995 to 0.999 98, a reduction in the gate error by over two orders of magnitude. Other transverse gates similarly show strong improvements.
Chemical etching of Sb2Se3 solar cells: surface chemistry and back contact behaviour
Authors: Shiel Huw , Hutter Oliver S , Phillips Laurie J , Turkestani Mohammed Al , Dhanak Vin R , Veal Tim D , Durose Ken , Major Jonathan D
Published: August 2019

The effect of (NH4)2S and CS2 chemical etches on surface chemistry and contacting in Sb2Se3 solar cells was investigated via a combination of x-ray photoemission spectroscopy (XPS) and photovoltaic device analysis. Thin film solar cells were produced in superstrate configuration with an absorber layer deposited by close space sublimation. Devices of up to 5.7% efficiency were compared via current–voltage measurements (J–V) and temperature-dependent current–voltage (J–V–T) analysis. XPS analysis demonstrated that both etching processes were successful in removing Sb2O3 contamination, while there was no decrease in free elemental selenium content by either etch, in contrast to prior work. Using J–V–T analysis the removal of Sb2O3 at the back surface in etched samples was found to improve contacting by reducing the potential barrier at the back contact from 0.43 eV to 0.26 eV and lowering the series resistance. However, J–V data showed that due to the decrease in shunt resistance and short-circuit current as a result of etching, the devices show a lower efficiency following both etches, despite a lowering of the series resistance. Further optimisation of the etching process yielded an improved efficiency of 6.6%. This work elucidates the role of surface treatments in Sb2Se3 devices and resolves inconsistencies in previously published works.
Variation in chick-a-dee call sequences, not in the fine structure of chick-a-dee calls, influences mobbing behaviour in mixed-species flocks
Authors: Landsborough Blaine , Wilson David R , Mennill Daniel J
Published: August 2019

When animals vocalize under the threat of predation, variation in the structure of calls can play a vital role in survival. The chick-a-dee calls of chickadees and titmice provide a model system for studying communication in such contexts. In previous studies, birds’ responses to chick-a-dee calls covaried with call structure, but also with unmeasured and correlated parameters of the calling sequence, including duty cycle (the proportion of the calling sequence when a signal was present). In this study, we exposed flocks of Black-capped Chickadees (Poecile atricapillus) and heterospecific birds to playback of chick-a-dee calls and taxidermic models of predators. We quantified birds’ responses to variation in number of D notes and duty cycle of the signalling sequence. Chickadees and heterospecific birds responded more intensely to high-duty-cycle treatments, and equally to treatments where duty cycle was held constant and the number of D notes varied. Although our study does not disentangle the effects of call rate and duty cycle, it is the first to investigate independently the behavioural responses of birds to variation in structural and sequence-level parameters of the chick-a-dee call during a predator confrontation. Critically, our results confirm that the pattern previously observed in a feeding context holds true in a mobbing context: variation in calling sequences, not in call structure, is the salient acoustic feature of chick-a-dee calls. These results call into question the idea that chick-a-dee call structure carries allometric information about predator size, suggesting instead that sequence-level parameters play a central role in communication in a mobbing context.
Ovarian cholesterol efflux: ATP-binding cassette transporters and follicular fluid HDL regulate cholesterol content in mouse oocytes†
Authors: Quiroz Alonso , Molina Paz , Santander Nicolás , Gallardo Daniel , Rigotti Attilio , Busso Dolores
Published: August 2019

High density lipoproteins (HDL) take up cholesterol from peripheral tissues via ABC transporters and deliver it to the liver via scavenger receptor class B type I (SR-B1). HDL are the main lipoproteins present in follicular fluid (FF). They are thought to derive from plasma, but their origin is still controversial. SR-B1 knock-out (KO) mice have provided important evidence linking HDL metabolism and female fertility. These mice have cholesterol-rich circulating HDL and female infertility that can be restored by treating mice with the cholesterol-lowering drug probucol. Ovulated oocytes from SR-B1 KO females are dysfunctional and show excess cholesterol. The mechanisms explaining the contribution of FF HDL to oocyte cholesterol homeostasis are unknown. Here, using quantitation of filipin fluorescence we show that in SR-B1 KO ovaries, cholesterol excess is first observed in immature oocytes in antral follicles. By performing cross-transplant experiments between WT and apolipoprotein A-I deficient (ApoA-I KO) mice, which lack the main protein component of HDL, we provide evidence supporting the plasmatic origin of FF HDL. Also, we demonstrate that probucol treatment in SR-B1 KO females results in lowering of cholesterol content in their oocytes. Incubation of oocytes from SR-B1 KO mice with purified WT HDL reduces their cholesterol content, suggesting that HDL promote efflux of excess cholesterol from oocytes. In agreement with this hypothesis, we identified ABC transporters in oocytes and observed that ABCA1 KO oocytes have excess cholesterol and lower viability than WT oocytes.
Percutaneous coronary intervention to left anterior descending artery/right coronary artery bifurcation: this is not a typo! A case report
Authors: Khan Usman Azhar , Sharma Divyesh , McGlinchey Paul , Peace Aaron
Published: August 2019

Background

Anomalous origin of the right coronary artery (RCA) is a rare congenital anomaly. A single coronary artery arising from the left sinus of Valsalva, with the RCA originating from the left anterior descending artery (LAD), is extremely rare. We report the case of an anomalous origin of the RCA from the mid LAD with a significant bifurcation lesion, in the setting of an acute coronary syndrome, endangering both the RCA and LAD territories.

Case summary

An 85-year-old female presented with a non-ST elevation acute coronary syndrome. Transradial coronary angiography revealed an anomalous origin of the RCA arising from the mid LAD beyond a large first septal perforator. There was significant stenosis involving anomalous RCA/LAD bifurcation classified as Medina 1, 1, 1. Following discussion at heart team meeting, she underwent successful percutaneous coronary intervention. The LAD/RCA bifurcation was treated using a two-stent culotte technique without any complications. Computed tomography coronary angiogram was performed which confirmed a benign course of the anomalous RCA anterior to aorta and pulmonary artery.

Discussion

This anomaly poses a significant challenge in revascularization due to the large area of myocardium subtended by the LAD and RCA and usually an acute angle of bifurcation. Moreover, CTCA can be useful to ascertain the course of anomalous RCA.
A case report of a giant hiatal hernia mimicking an ST-elevation myocardial infarction
Authors: Rubini Gimenez Maria , Gonzalez Jurka Leander , Zellweger Michael J , Haaf Philip
Published: August 2019

Background

Acute coronary syndrome (ACS) can be a life-threatening condition. However, identification of patients with ACS can be challenging, especially among women, and clinical presentation can often overlap with other medical entities.

Case summary

A 61-year-old woman with a history of stable bronchial asthma presented with worsening dyspnoea for spiroergometry. During bicycle exercise testing, she developed acute chest pain and her electrocardiogram showed significant ST-segment elevations. High-sensitivity cardiac troponin was elevated and a coronary angiography was performed showing normal coronary arteries. Cardiac magnetic resonance imaging showed no signs of myocardial infarction, myocarditis or Takotsubo cardiomyopathy but the incidental finding of a giant hiatal hernia impeding the filling of the left atrium. The giant hernia was surgically corrected, and the patient’s exertional dyspnoea fully relieved during follow-up.

Discussion

Hiatal hernia might compress cardiac structures, cause exertional dyspnoea and mimic ST-elevation myocardial infarction.