bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling of Saltwater Evaporation using WAIV
Authors: Henrietta  , Santoso H , Witono J R 
Published: March 2020

Abstract
Indonesia as a country, which has the second longest coastline in the world, has a big opportunity to improve its salt production. The productivity of salt production in Indonesia from 2011 to 2014 was around 67, 92, 40, and 90 tons/ha/year, respectively. This low productivity was mainly due to the method of salt production used, which was very traditional and depended mainly on the availability of solar energy for evaporation. The longer the dry season was, the higher the salt production would be in that year, and vice versa. Since the performance of evaporation process holds the key to the improvement of productivity of salt production, it is important to study a method that can speed up the evaporation process in the salt production. One of the recent methods that can be used to achieve that purpose is the Wind Aided Intensified Evaporation (WAIV) process. In this study, a model for saltwater evaporation in a WAIV unit using Harbeck equation is proposed. Two set of data for saltwater evaporation in a WAIV unit was extracted from literature. The first set of data was used to obtain the parameters of Harbeck equation by minimizing the sum of error squares of the cumulative evaporation rate in a WAIV unit compared to its model. The second set of data was used to validate the model. It is found that the proposed model can estimate the evaporation rate in a WAIV unit based on the surrounding climate data reasonably well.
Development of Skin Lotion Containing Antioxidant Extract from Coffee Pulp and Study on Its Stability
Authors: Widiputri D I , Wijaya S , Kusumocahyo S P 
Published: March 2020

Abstract
Coffee pulp, a major coffee waste in the coffee industry, has been found to contain bioactive compounds that can provide high antioxidant activity and hence, can be utilized as a natural antioxidant source. One of the beneficial utilizations of coffee pulp extract is its application in skin cosmetics, such as skin lotion. The application of antioxidant on the skin is one way to avoid skin damages and diseases from happening, which can be caused by free radicals generated through ultraviolet (UV) radiation from sunlight. The aim of this study is to apply the coffee pulp extract powder into skin lotion formulation, and to study the phenolic content, antioxidant activity and the stability of the formulated lotions. First, the coffee pulp (CP) was extracted at sample to solvent ratio of 1:10 (w/v) using ethanol/water mixtures at various extraction temperatures and times to obtain the optimum extraction condition. The resulting coffee pulp extract at optimum condition (50°C, 120 minutes) was pulverized into coffee pulp extract powder. The yield of the pulverization was 0.217146 g powder/g CP. The coffee pulp extract powder was then added into skin lotion formulation with four different concentrations (0.125 %, 0.25 %, 0.5 % and 1 % by mass). All coffee pulp skin lotions were found to show good physical stability and considerably higher antioxidant activity (IC50 : 5,805 ppm – 55,776 ppm) compared to commercial lotions (IC50 : 505,018 ppm – 557,218 ppm).
Application of Quantitative Structure-Property Relationship (QSPR) Models for the Predictions of Critical Micelle Concentration of Gemini Imidazolium Surfactants
Authors: Setiawan Ely , Mudasir  , Wijaya Karna 
Published: March 2020

Abstract
The critical micelle concentration (cmc) is important indexes to determine the performance of surfactants quantitatively. In this study, based on the molecular descriptors, which calculated, by Dragon software, were proposed a quantitative structure-property relationship analysis for prediction of cmc of gemini imidazolium surfactants. In the present study, the associative neural networks (ASNN) and multiple linear regression analysis (MLRA) technique were used to interpret the chemical structural functionality (molecular descriptors) against the cmc of gemini imidazolium surfactants. The models were validated rigorously through 5-fold cross-validation. The ASNN method showed to be better than the MLRA method in terms of the internal and the external prediction accuracy with high statistical quality r2 = 0.96, q2 = 0.95, RMSE = 0.08 and MAE = 0.04 respectively. The developed QSPR models are publicly available on the web site at https://ochem.eu/model/11583111 for ASNN model and https://ochem.eu/model/43858671 for MLRA model. These models can be applied to predict the cmc of new gemini imidazolium surfactants.
Effect of Particle Size and Shaking Speed on Enhancing Concentration of Manganese using Shaking Table
Authors: Prasetya Agus , Ahsa Winayu Mutiara , Gustiana Himmah Sekar Eka Ayu , Astuti Widi , Petrus Himawan Tri Bayu Murti 
Published: March 2020

Abstract
Increased levels of elements or minerals from ore are usually always done in the metallurgical industry. In the present investigation, low grade manganese ores from Kulonprogo, Yogyakarta has investigated by gravity methods using shaking table. In this context, the effect of different process variables such as particle size (-60 + 100 mesh; -100 + 200 mesh and -200 + 270 mesh) and shaking speed (80 rpm, 100 rpm and 120 rpm) was analysed. The table slope and wash water flow rate are a constant variable, which are at 11° and 13 dm3/minute. The interactional effects between different process variables were analysed using contour plot. It was founded that enhancement of the concentration of Mn is more than 5% with the shaking speed condition of 100-120 rpm and the particle size of 0.17 mm. Second order quadratic equations have developed to predict enhancement of Mn concentration using shaking table.
The Effect of Salt-GDL Coagulant and Temperature on Tofu Quality
Authors: Inggrid Maria , Hananjaya Nikolas 
Published: March 2020

Abstract
Soymilk tofu can be coagulated with salts, acid and lactones. The objectives of this investigation was to study the effect of temperature and different coagulant to the quality of tofu; such as protein content, texture, mass and moisture. Soybean was oaked and grinded to produced soymilk. The soymilk was coagulated with two type of mixed coagulant; CaSO4- Glucono delta-lactone (GDL) and MgSO4-GDL, the variation of composition were 0:4, 3:1, 2:2, 1:3, 0:4 at temperature of 70°C and 80°C. The highest protein content was obtained from the tofu with CaSO4-GDL (2:2) and 70°. The results showed that the different in coagulation temperature affect the protein content of tofu. Mass and texture of the tofu increased as the composition of salt coagulant increased. General factorial method was used in this experiment, the result supports that the various composition of coagulant increased significantly (P<0.05) from 111-135 gram and 241-642 gram, respectively for tofu mass and texture. Temperature has significant result to protein content and mass of the tofu.
Thermal Conductivity of Geopolymer with Polypropylene Fiber
Authors: Rastri Utami Felisitas Aprilia , Triwiyono Andreas , Agustini Ni Komang Ayu , Perdana Indra 
Published: March 2020

Abstract
Geopolymer is widely used to replace cement for fire-resistant products. The benefits of geopolymer based on fly ash are cost-effective and easy process production. Lightweight products are needed to minimize dead load for the existing structure. The addition of polypropylene fiber is intended to produce relative lightweight and strong material applied for fire resistance. This research was conducted to obtain thermal conductivity, density, and compressive strength of the geopolymer. The ratio of activator/fly ash (a/f) was varied 40%, 45%, and 50% with addition of polypropylene fibers of 0.5%, 1%, and 1.5% of the fly ash weight. The experimental test was conducted on the 7th day at ambient temperature while concentration of NaOH used in geopolymer synthesis was kept at 10M with a ratio of alkaline activator (Na2SiO3/NaOH) of 2. The test results showed that thermal conductivity (λ) is in a range between 0.19-0.82 W/m.C while the thermal conductivity is less than 1 W/m.C. This indicates that the geopolymer can be applied for thermal insulating material. Geopolymer with polypropylene fiber and a/f 50% can be classified as lightweight material with a density around 1.6283-1.7625 gr/cm3. The ratio of a/f 50% produces a compressive strength ranging from 18.14 MPa to 28.42 MPa.
Valuable Metals Precipitation of Low Grade Nickel Ore Leachate Using Sodium Hydroxide
Authors: Surianti  , Utami A N , Permatasari M A , Bendiyasa I M , Astuti W , Petrus H T B M 
Published: March 2020

Abstract
Nickel metal is widely used in various industries. Nickel sources come from nickel sulfide ores and nickel oxide ores (laterite). Nickel content in laterite ore is 1.5-2.5 % (weight basis), lower than the nickel content in sulfide ores. Indonesia is one of the major nickel producers with laterite nickel ore reserves of 1576 million tons or 15 % of total world reserves. The distribution of laterite nickel in Indonesia is found in several regions such as Maluku, Sulawesi and Papua. However, the low grade nickel processing in Indonesia has not been well established. Thus research on valuable metals extraction from ow grade nickel ore has put some interest to some researchers. In this study, precipitation of valuable metals from low grade nickel leachate was conducted using sodium hydroxide as the precipitation reagent. Nickel ore used in this experiment was obtained from Pomalaa, Southeast Sulawesi. After leaching at optimum condition resulting of about 75 % recovery of nickel using HCl (1 M at 90 °C and stirring for 1 hour), the leachate was then added sodium hydroxide to varied pH of 8, 10, and 12. Along with the pH conditioning, temperature was kept to the value of 55 °C, 70 °C, and 85 °C. The optimum nickel recovery of 83.97 % is obtained at pH 12 and temperature of 85 °C. The residual metals concentration in the solution after precipitation was analyzed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES).
Synthesis and Characterization of Activated Carbon Derived from Salacca Peel Using ZnCl2 Hydrothermal Carbonization and Chemical Activation with Microwave Heating
Authors: Kristianto Hans , Lavenki Yoel , Susanti Ratna Frida 
Published: March 2020

Abstract
In this paper we describe synthesis and characterization of salacca peel derived activated carbon. The salacca peel was carbonized using hydrothermal carbonization (HTC) at 225°C and 50 bar for 5 h with and without ZnCh as HTC catalyst. The obtained hydrochar was furthermore activated using microwave assisted chemical activation at 700 W for 8 min under inert atmosphere. The ratio between hydrochar and impregnant (ZnCl2) was varied between 1:2, 1:3, and 1:4. The samples were characterized using methylene blue equilibrium adsorption, Scanning Electron Microscopy (SEM), and Fourier Transform Infra-Red (FTIR) spectroscopy. It was obtained that the presence of catalyst during HTC could increase the methylene blue adsorption capacity (qe) and visible pores on the surface. The increase of impregnation ratio gave increase the surface pores and qe, with highest qe was obtained at impregnation ratio of 1:4. Furthermore, the obtained activated carbon had higher qe and oxygen functional groups compared to that of commercial activated carbon, making it suitable for various applications.
Preparation of Salacca Peel Based Activated Carbon using CeCl3 Catalyzed Hydrothermal Carbonization and Microwave Induced KOH Chemical Activation as Ni-Ion Capacitor Electrode
Authors: Ondy F C , Chrismanto C , Susanti R F , Kristianto H , Devianto H 
Published: March 2020

Abstract
Activated carbon is a highly porous non-graphite carbon material. Activated carbon has been used for various applications, namely adsorbent, catalyst support and electrode. As supercapacitor’s electrode, activated carbon has a high energy density and fast charge - discharge. In this study, salacca peel used as precursor to synthesized activated carbon through hydrothermal carbonization (HTC) and microwave induced chemical activation. The hydrochar (HC) was synthesized at 225°C, 5 bar for 5 h using cerium (III) chloride as catalyst. Furthermore, KOH was used as activating agent at various HC to KOH mass ratio at 1:2 (CE2), 1:3 (CE3), and 1:4 (CE4), under microwave irradiation at 700 W for 8 min. Activated carbon samples were analyzed using methylene blue adsorption capacity method, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The CE4 sample gave highest methylene blue adsorption capacity, indicating high surface area. This sample was used as nickel ion’s capacitor electrode with nickel oxide as the reference electrode and 6 M KOH as the electrolyte. The electrochemical characteristic was studied using cyclic voltammetry (CV) with various scan rates (2 mV/s, 5 mV/s, 10 mV/s) for the nickel ion’s capacitor electrode. It was obtained that CE4 provided higher capacitance compared to commercial activated carbon.
Preparation of Activated Carbons Originated from Orange Peel Waste by Subcritical H2O Activation Method
Authors: Hady Dandy , Susanti Ratna Frida , Arie Arenst Andreas 
Published: March 2020

Abstract
Low-cost and environmental friendly activated carbons were synthesized from orange peel waste by carbonization followed by activation process using subcritical water. The carbonization process of orange peel waste was conducted in the electrical furnace at temperature of 800°C for 2 h. Activation process of the impregnated orange peel was carried out in the tubular furnace for 1 h at activation temperature of 200°C and pressure variation of 120, 170 and 220 bar. Activated carbon with highest surface area of 491 m2/g was obtained by water pressure of 170 bar. The activated carbons were then utilized as adsorbents for removal of methylene blue (MB) from aqueous solution. The batch adsorption study was carried out by varying the initial concentration of MB solution (2, 4, 6, 8 and 10 ppm). Experimental results showed that the adsorption kinetic of MB fitted the pseudo-second-order rate equation, whereas for the adsorption isotherm model followed two models i.e. the Dubinin-Radushkevich and Freundlich model. The adsorption mechanism was found to be governed by the intraparticle and surface diffusion mechanism.
Strength of Hydrated Cement Based on Borogypsum
Authors: Gordiyenko P S , Yarusova S B , Demidov M I , Buravlev I Yu , Zhevtun I G , Gulyaev V T , Pashnina E B , Ivanenko H B , Shabalin I A 
Published: March 2020

Abstract
The paper presents research into the strength of hydrated cement based on borogypsum.
Calculation Method Analysis for Structure Strengthening with External Reinforcement
Authors: Kuzina E S , Rimshin V I 
Published: March 2020

Abstract
This article describes the main provisions of the calculating method for the gain of reinforced concrete structures by the system of external reinforcement. As an example, the calculation of monolithic reinforced concrete slab with carbon fiber material using the SCAD Office software package was considered and analyzed, which most accurately reflects the geometry and physico-mechanical parameters of the structure. The calculation of reinforced concrete structures includes engineering survey to determine the existing physic-mechanical characteristics of materials, perform calibration calculations and stress calculations in reinforced concrete structures of buildings and structures, taking into account the existing stiffness characteristics, designing reinforcement engineering solutions, the calculation of the forces in the structures and verification of the structures bearing capacity after the reinforcement is completed. During the survey of reinforced concrete structures, it is determined existing loads, deformations, deflections, physico-mechanical characteristics for the subsequent selection of the composite material cross section and taking them into account after the concrete structure’s reinforcement. The external reinforcement systems is used for reinforcing concrete structures and rely on tensile stress perception, taking into account the joint deformations of the composite material used for reinforcement and the concrete structure. The calculation of reinforced concrete structures carried out on the first and second limit state. If the load after reinforcement with a composite material does not increase compared with the loads at the stage of the reinforced concrete structure operation, the calculation for the second group of limit states is not performed. The reinforced concrete structures calculation using an external reinforcement system made of composite materials is carried out from the joint operation conditions of the installed external reinforcement and the concrete base before the limit state onset. The calculation is performed in two stages: at the first stage, the reinforced concrete structure is calculated without reinforcement taking into account the existing loads and deformations, at the second stage, after the work on reinforcement, the design is calculated taking into account the efforts and deformations in the first stage.
Researches of the Seismic Properties of Clay Soils for Seismic Microzoning
Authors: Olyansky Yu I , Shekochihina E V , Kalinovsky S A 
Published: March 2020

Abstract
The paper presents the results of seismoacoustic studies of soils on the example of samples of unsalted Sarmatian clays from the Northern black sea region. Samples of natural addition and humidity, as well as corresponding samples of soil particles were studied. Regression dependences of the longitudinal wave velocity on some indices of physical and mechanical properties of Sarmatian clays are revealed. The values of elastic wave propagation velocities determined as a result of ultrasonic investigations are used to calculate the increment of the seismic score and to map seismic microzoning, which is extremely important for ensuring the safety of construction in seismic areas. The obtained results can be used for seismic microzoning of any areas composed of clay swollen soils.
Methodology for Comparison of Building Daylighting Systems
Authors: Kononova M S , Zherlykina M N , Kononov A A 
Published: March 2020

Abstract
The energy balance of buildings depends greatly on the type of external fencing, including translucent. The article presents a brief description of different types of daylighting systems that have different optical, geometric and thermal characteristics. The change in these characteristics affects the quality of lighting in the room, as well as determines the operating costs associated with losses and heat flows into the building through translucent fences. The task of comparing and choosing the optimal daylighting system should take into account all of the above factors. The authors propose a complex comparison criterion that takes into account thermal, optical, operational properties and capital costs. The structure of the proposed criterion allows you to add new indicators or remove irrelevant for a particular consumer comparison parameters. The method is composed and the calculated dependences for determining the numerical value of individual indicators included in the complex criterion are given. All parameters included in the proposed criterion have no dimension. This makes it possible to reduce the dependence of the calculations on changes in current energy prices.
Field Research of the Heaving Pressure Occurring at Frost Penetration in the Soil under the Foundation Bed
Authors: Kim Vyacheslav , Kim Marina , Kim Michael 
Published: March 2020

Abstract
This article describes the results of field experimental studies of the heaving pressure development during freezing of the soil under the foundation bed. Due to the intensive development of areas North and North-East of Russia, studies on the impact of heaving soils on foundations and underground structures are currently assuming a special significance. The research that we carried out allowed us to reveal features of the heaving pressure development of clay soils during freezing under the foundation bed depending on conditions of freezing. We found that pressure formation depends largely on the location of the frozen area and the compressibility of the melt zone of the freezing soil. In the article, we propose measures to reduce the impact of heaving pressure on the foundation bed.
On the Application of High-Strength Reinforcement in Beamless Slab
Authors: Kuznetsov V S , Shaposhnikova Yu A 
Published: March 2020

Abstract
The paper considers the peculiarities of the stress-strain state in the zone of junction of the slab of slabs with the joint using conventional and high-strength reinforcement. The maximum stresses in the stretched concrete before cracking correspond to the tensile strength of the concrete, and the stresses in the reinforcement before cracking depend on the reduction factor and were calculated for various classes of concrete. After the formation of cracks, the increase in stresses in the tensioned reinforcement depends on the width of the crack opening and the deformation of the reinforcement between the cracks. The paper shows that with a sufficient width of crack opening and a certain distance between the cracks, high-strength reinforcement can be used to increase the bearing capacity of the support sections of the plate. The total stresses in the reinforcement were calculated for different crack opening widths and different distances between the cracks, the results of which were used to plot the graphs. The graphs of the dependence of the content of high-strength reinforcement on the strength of the normal section, as well as the graphs of the growth of strength with different ratios of the number of rods, are plotted. According to the results of the work, it can be seen that, depending on the class of high-strength reinforcement and its quantity, the strength of normal sections can be increased up to two times.
Current Trends in Urban Design
Authors: Meseneva N V 
Published: March 2020

Abstract
With the development of urbanization processes, the urban environment is changing, the usual parameters of convenience of the urban environment are being transformed, the issues of integrity formation of the artistic image of the city become more relevant. These changes create the need for a study of modern approaches to the formation of the visual environment of the city. The task of architects is to design a comfortable, harmonious environment that takes into account new requirements and technologies. The modern environment of the city includes a number of components that affect the quality of life, have an emotional impact on citizens: the architecture of buildings and constructions, the landscape, the panorama of the city, historical traditions, culture, ecology, climate, and much more. Today, when organizing the urban environment, it is necessary to take into account current trends in the design of architecture, landscape, color and lighting solutions, advertising, decorative and monumental art, to organize a flexible, changeable urban environment.