Linear Graphical Method Research Articles

Heat Loss Optimization of a Building with Different Window to Wall Area Ratios

Abstract The types of glass and exterior walls and the window-to-wall ratio (WWR) on building façades play a major role in heat losses that occur in every type of building, residential or commercial. The opaque and transparent surfaces of buildings have an important role in terms of both energy losses and energy gains. Windows are the parts of the building envelope where heat losses mostly occur. As the WWR increases on the façades of a building, heat losses increase, but heat gains from solar energy also increase, which assists in free heating of the building. In this study, a detached residential building located in Antalya, Turkey, a province with hot–humid climatic conditions, has been examined. A series of simulations were carried out to detect the effects of WWRs and different glass, frame, and exterior wall types on heat losses of the building. The heat loss values obtained from these simulations were processed by using a special mechanical installation calculation software. Simulations were performed for apartment rooms with levels of WWR ranging from 30 to 60 % of the wall areas facing the façade. In order to minimize heat loss, double-pane glass (or double-glazed glass) was used instead of single-pane glass. The aim of this study was to find the optimum value in terms of applicability and economy. The optimum value was calculated by minimization according to both the linear graphical method and the dual simplex optimization method. The values found in both methods were compared and interpreted. It is believed that the optimized glass, frame, joinery, and exterior wall parameters, which are influential to the energy performance of the building, will make a positive contribution to the architectural design phase in addition to improving the energy efficiency of existing buildings.

Modeling and Simulation of Elevation Dynamics of Main Battle Tank Weapon System with Linear Graph Method

The use of main battle tanks in armies goes back many years. The most crucial component is undoubtedly the weapon system. In this study, it is aimed to model the elevation dynamics of the weapon system that provides the movement of the weapon system in the vertical axis. The elevation dynamics consists of three parts: an electric motor, a driver, and a barrel. Both parts are expected to have similar vibration characteristics. The linear graph method was preferred as the modeling method. First of all, the system components and types were determined, and the linear graph, normal tree, and tree links of the system were drawn. Then the state variables, primary and secondary variables, as well as the number of branches, nodes, and sources, were determined, respectively. Elemental, continuity, and compatibility equations were written using the obtained graphs. By organizing these equations, state equations were obtained in standard form and matrix form. With the simulation studies carried out in MATLAB/Simulink, the displacement, velocity, and acceleration responses of the breech and muzzle sections were obtained. It is seen that obtained angular displacement, velocity, and acceleration results for both breech and muzzle sections are almost the same. As a result, the breech and muzzle sections have similar vibration motions and have proven to be able to work in harmony. This result shows that the barrel can be designed from two parts without additional stress and tension, which makes it difficult to focus on the target. By forming the barrel in two parts, the risk of damage can be minimized by better distributing the stress and tension occurring in the barrel during firing.

Synthesis and Characterization of Statistical and Block Copolymers of n-Hexyl Isocyanate and 3-(Triethoxysilyl) Propyl Isocyanate via Coordination Polymerization.

Well-defined statistical copolymers of n-hexyl isocyanate, HIC, and 3-(triethoxysilyl)propyl isocyanate, TESPI, were synthesized via coordination polymerization mechanism, employing a chiral half-titanocene complex as initiator. The monomer reactivity ratios of the statistical copolymers were calculated using linear graphical methods and the computer program COPOINT in the frame of the terminal model. The molecular and structural characteristics of the copolymers were also calculated. The kinetics of the thermal decomposition of the statistical copolymers was studied by Thermogravimetric Analysis, TGA, and Differential Thermogravimetry, DTG, and the activation energy of this process was calculated employing several theoretical models. In addition, block copolymers constituted from PHIC and PTESPI blocks were synthesized by sequential coordination polymerization. All samples were characterized by nuclear magnetic resonance, NMR, spectroscopy and size exclusion chromatography, SEC. The thermal stability of the blocks was also studied by TGA and DTG and compared to the corresponding statistical copolymers.

Statistical Copolymers of N-Vinylpyrrolidone and 2-Chloroethyl Vinyl Ether via Radical RAFT Polymerization: Monomer Reactivity Ratios, Thermal Properties, and Kinetics of Thermal Decomposition of the Statistical Copolymers.

The radical statistical copolymerization of N-vinyl pyrrolidone (NVP) and 2-chloroethyl vinyl ether (CEVE) was conducted using the Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization technique, employing [(O-ethylxanthyl)methyl]benzene (CTA-1) and O-ethyl S-(phthalimidylmethyl) xanthate (CTA-2) as the Chain Transfer Agents (CTAs), leading to P(NVP-stat-CEVE) products. After optimizing copolymerization conditions, monomer reactivity ratios were estimated using various linear graphical methods, as well as the COPOINT program, which was applied in the framework of the terminal model. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the monomers' mean sequence lengths. Thermal properties of the copolymers were studied by Differential Scanning Calorimetry (DSC) and kinetics of their thermal degradation by Thermogravimetric Analysis (TGA) and Differential Thermogravimetry (DTG), applying the isoconversional methodologies of Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS).

Novel methacrylate copolymers functionalized with fluoroarylamide; copolymerization kinetics, thermal stability and antimicrobial properties

In the first step of this study, 2-oxo-2-[(2,4,6-trifluorophenyl)amino]ethyl-2-methylprop-2-enoate(OTFAMA) monomer was synthesized and characterized. Then, a series copolymers were obtained by free-radical copolymerization method of OTFAMA and glycidyl methacrylate (GMA), which is a commercial monomer at 65 °C in 1,4-dioxane solvent. Structural characterizations of synthesized monomer and copolymers were carried out using FTIR, 1H-13C-NMR instruments. The composition of the copolymers was estimated by elemental analysis. The reactivity ratios (r 1 and r 2) were obtained from the various linear graphical methods. The values of r 1 (OTFAMA) = 0.33 and r 2 (GMA) = 0.45 were found from the same graphical methods. The thermal behaviors of all the polymers have been investigated using the differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA). A kinetic study of the thermal decompostion of copolymers was investigated using thermogravimetric analyzer with non-isothermal methods selected for analyzing solid-state kinetics data. The average activation energy values were calculated via Kissinger and Ozawa models in a period of α = 0.10–0.80. Photo stability of the copolymers was investigated. Also, the biological activity of the copolymers against different bacterial and fungal species has been investigated.

Optimization of Production Benefits Through the Linear Program Graph Method

Production at Zentha Meubel is experiencing constraints due to the availability of wooden planks and the time spent making cabinets and tables. Meanwhile, the company wants to get optimal profit. To solve this problem, this study aims to utilize a linear graphical method program to optimize production profits at Mr. Andarias' Zentha Meubel. This research is a qualitative research type of phenomenology. The process carried out in optimizing the production is collecting data by interview and observation. Furthermore, a mathematical model is made and then optimizes the production profit using the graphical method. The results with the graph method show that production at Zentha furniture will achieve optimal results if it produces 15 units of cabinets with a profit of Rp. 18,750,000. The results of the optimization calculation using the graph method will increase the profit of Rp. 2,250,000.

Mathematical Modelling of Electrically Driven Elevator via Linear Graph Method, Dynamic Response Analysis and Active Vibration Control

Viscous friction occurs between the roller guide shoes and guide rail because of the grease layer.This friction causes to vibration on the cage. This study’s aim is an investigation and active control of that vibration for passengers. Initially, the passenger elevator’s dynamics modeling is carried out by Linear Graph Method. The DC motor and AC motor parameters are used in the system modeling separately. Then, vibrations occurred on the elevator cabin are observed. Finally, the effect of vibrations is reduced with the aid of an active controller. The time and frequency responses are compared for two kinds of the motor.

Statistical Copolymers of n-Butyl Vinyl Ether and 2-Chloroethyl Vinyl Ether via Metallocene-Mediated Cationic Polymerization. A Scaffold for the Synthesis of Graft Copolymers.

The cationic statistical copolymerization of n-butyl (be) and 2-chloroethyl vinyl ether (CEVE), is efficiently conducted using bis(η5-cyclopentadienyl)dimethyl zirconium (Cp2ZrMe2) in combination with tetrakis(pentafluorophenyl)borate dimethylanilinum salt [B(C6F5)4]–[Me2NHPh]+, as an initiation system. The reactivity ratios are calculated using both linear graphical and non-linear methods. Structural parameters of the copolymers are obtained by calculating the dyad sequence fractions and the mean sequence length, which are derived using the monomer reactivity ratios. The glass transition temperatures (Tg) of the copolymers are measured by Differential Scanning Calorimetry (DSC), and the results are compared with predictions based on several theoretical models. The statistical copolymers are further employed as scaffolds for the synthesis of graft copolymers having poly(vinyl ether)s as a backbone and either poly(ε-caprolactone) (PCL) or poly(l-lactide) (PLLA) as side chains. Both the grafting “onto” and the grafting “from” methodologies are employed. The reaction sequence is monitored by Size Exclusion Chromatography (SEC), NMR and IR spectroscopies. The advantages and limitations of each approach are thoroughly examined.

Methacrylate copolymers and their composites with nano-CdS: synthesis, characterization, thermal behavior, and antimicrobial properties

Homo- and copolymers of 2-(N-phthalimido)ethyl methacrylate (NPEMA) and p-chlorophenyl methacrylate (PCPMA) were prepared in N,N-dimethyl formamide (DMF) solution at 70 °C using 2,2-azo-bisisobutyronitrile (AIBN) as initiator. The nano-CdS-doped polymer composite of NPEMA and PCPMA was prepared via in situ technique. The homo- and copolymers of NPEMA and PCPMA were characterized using FT-IR spectroscopy and gel permeation chromatography (GPC). The polymer nano composites were characterized using FT-IR spectroscopy, X-ray diffraction, and transmission electron microscopy. The reactivity ratios (r1 and r2) were obtained from the various linear graphical methods. The values of r1 (NPEMA) = 0.55 and r2 (PCPMA) = 1.30 were found from the same graphical methods. The copolymer microstructures were found from the mean sequence length, run number, and dyad fraction. Thermal behavior of polymers and polymer nano composites under nitrogen atmosphere was studied. The activation energies of neat polymers were varied in the range of 56–85 kJ/mol, while 28–56 kJ/mol energies were found for nano-CdS-doped polymer composites. The thermodynamic parameters of thermal degradation were also obtained. Kinetic and thermodynamic parameters were confirming the stability of the neat polymers than polymer nano composites. The polymers were assessed on different microorganisms for obtaining the antimicrobial properties. Overall, the polymers permit 10–52, 20–58, and 18–56% growth of bacteria, fungi, and yeast, respectively.

Statistical copolymers of N-vinylpyrrolidone and benzyl methacrylate via RAFT: Monomer reactivity ratios, thermal properties and kinetics of thermal decomposition

ABSTRACTStatistical copolymers of N-vinylpyrrolidone (NVP) with benzyl methacrylate (BzMA) were prepared by Reversible Addition-Fragmentation chain Transfer Polymerization (RAFT), employing three different xanthates as RAFT agents: [(O-ethylxanthyl)methyl]benzene, [1-(O-ethylxanthyl)ethyl]benzene and O-ethyl S-(phthalimidylmethyl) xanthate. The reactivity ratios were estimated using the Fineman-Ross, inverted Fineman-Ross, Kelen-Tüdos and extended Kelen-Tüdos linear graphical methods, as well as the computer program COPOINT. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length. All the methods are in agreement that the probability for the incorporation of BzMA units is much greater than for that of NVP units. The glass-transition temperature (Tg) values of the copolymers were measured by Differential Scanning Calorimetry and examined by means of several theoretical equations, allowing for the prediction of these Tg values. Subsequently, a systematic and detailed investigation of the thermal degradation of these copolymers compared with that of the respective homopolymers, was carried out by Thermogravimetric Analysis, within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. As expected, the thermal stability of the copolymers is influenced by the structure of the substituents of the thiocarbonylthio end groups due to the RAFT agents.

Laboratory investigation and simulation of breakthrough curves in karst conduits with pools

A series of laboratory experiments are performed under various hydrological conditions to analyze the effect of pools in pipes on breakthrough curves (BTCs). The BTCs are generated after instantaneous injections of NaCl tracer solution. In order to test the feasibility of reproducing the BTCs and obtain transport parameters, three modeling approaches have been applied: the equilibrium model, the linear graphical method and the two-region nonequilibrium model. The investigation results show that pools induce tailing of the BTCs, and the shapes of BTCs depend on pool geometries and hydrological conditions. The simulations reveal that the two-region nonequilibrium model yields the best fits to experimental BTCs because the model can describe the transient storage in pools by the partition coefficient and the mass transfer coefficient. The model parameters indicate that pools produce high dispersion. The increased tailing occurs mainly because the partition coefficient decreases, as the number of pools increases. When comparing the tracer BTCs obtained using the two types of pools with the same size, the more appreciable BTC tails that occur for symmetrical pools likely result mainly from the less intense exchange between the water in the pools and the water in the pipe, because the partition coefficients for the two types of pools are virtually identical. Dispersivity values decrease as flow rates increase; however, the trend in dispersion is not clear. The reduced tailing is attributed to a decrease in immobile water with increasing flow rate. It provides evidence for hydrodynamically controlled tailing effects.

Metallocene-mediated cationic polymerization of vinyl ethers: Kinetics of polymerization and synthesis and characterization of statistical copolymers

ABSTRACTThe cationic polymerization of ethyl, n-butyl and iso-butyl vinyl ether, EVE, BVE and iBVE, respectively, was efficiently conducted using bis(η5-cyclopentadienyl)dimethyl hafnium, Cp2HfMe2, or bis(η5-cyclopentadienyl)dimethyl zirconium, Cp2ZrMe2 in combination with either tris(pentafluorophenyl)borate, B(C6F5)3, or tetrakis(pentafluorophenyl)borate dimethylanilinum salt, [B(C6F5)4]−[Me2NHPh]+, as initiation systems. The evolution of polymer yield, molecular weight and molecular weight distribution with time was examined. In addition, the influence of the initiating system, the monomer and the reaction conditions on the control of the polymerization was studied. Furthermore, statistical copolymers of EVE with BVE were prepared employing Cp2HfMe2 and [B(C6F5)4]−[Me2NHPh]+ as the initiation system. The reactivity ratios were estimated using both linear graphical and non-linear methods. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length, which were derived using the monomer reactivity ratios. The glass transition temperatures, Tg, of the copolymers were measured by Differential Scanning Calorimetry, DSC, and the results were compared with predictions based on several theoretical models. The kinetics of thermal decomposition of the copolymers along with the respective homopolymers was studied by thermogravimetric analysis within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies.

Determination of Hydrogeological Parameters of Aquifer Using the Air Compressor Pumping

When the buried depth of water level is very large, the air compressor is used in pumping test. In the limited conditions, the value of the water level was not measured, but the recovery value of water level could be measured. In this case, the sp value of the water level drawdown was not able to be measured accurately when the pumping test stopped. So the hydraulic conductivity of aquifer could only be determined according to the linear graphic method of the water level recovery test. However, water level recovery characteristics of each period were not the same, and the raising rate of water level were not equal. Thus, there was a deviation when the hydraulic conductivity was solved with the linear graphic method. According to the existing data, the thesis combined the water level recovery fitting of the entire curve fitting with Dupuit formula of artesian well, determining the sp value and hydrogeological parameters of aquifer. After comprehensive analysis, the parameters obtained are more reasonable, which can provide a good reference for in-situ mining of oil shale in this area.

Interpreting tracer breakthrough tailing in a conduit-dominated karstic aquifer

Abstract Breakthrough tailing has been observed during dye-tracing recovery tests in the Norville aquifer system (chalk), France. Karst-conduit flow and transport parameters were assessed using two different interpretative methods: the linear graphical method and the Chatwin method (implemented in the Qtracer2 program). The linear graphical method was used to model the observed tailing effects, which was explained by a second smaller delayed breakthrough curve. By comparing the results of tracertest interpretation for the two methods, it was possible to relate the area of this second curve to the importance of turbulent flow in spring discharge. The more turbulent the flow, the less important the contribution of the second breakthrough curve and the tailing effect. The observed tailing could possibly be controlled by hydrodynamics to a greater extent than usually expected, the tailing effectsbeing mostly attributed to diffusion phenomena. Tailing effects were expected to increase with discharge and the piezometric level, which would have resulted in overpressure in conduits, fissure flooding, etc. Instead, breakthrough tailing tended to disappear with increasing aquifer discharge, which would support the hypothesis of there being mostly hydrodynamic-controlled tailing effects instead of matrix- or fissure-diffusion.

A linear graphical method to predict the effect of compaction on the hydraulic conductivity of clay liners and covers

It is proposed to present compaction relationships by plotting the inverse of the dry density versus the molding water content. In the proposed graph, the curves for equal degree of saturation become straight lines. The proposed new graph is shown to be very convenient to assess the saturated hydraulic conductivity, k sat, of non-swelling compacted clay, using a dual porosity model. The value of k sat depends on the secondary porosity between clay clods. The equation developed for equal k sat value appears also as a straight line in the proposed graph. It facilitates the prediction of k sat from field compaction data and thus the prediction of field performance of clay liners and covers.

Analysis of ligand binding process using binding capacity concept.

Binding capacity is the homotropic second derivative of the binding potential with respect to the chemical potential of the ligand. It provides a measure of steepness of the binding isotherm and represents the extent of cooperativity. In the present study, the shape of the binding capacity curve for various systems was investigated and the relation between binding capacity and the extent of cooperativity examined. In this regard, a novel linear graphical method was introduced for binding data analysis. The stoichiometry of binding and the extent of cooperativity can be determined by this method. This method has been successfully applied to various systems such as binding of oxygen to hemoglobin, warfarin to human serum albumin and dodecyltrimethylammonium bromide to alpha-amylase.

Determination of monomer reactivity ratios usingin situ FTIR spectroscopy for maleic anhydride/norbornene-free-radical copolymerization

Monomer reactivity ratios for maleic anhydride (MAH) and norbornene (Nb) free-radical copolymerizations were estimated by using a linear graphical method, which is based upon the terminal model developed by Mayo and Lewis. Reactions were performed by using optimized reaction conditions that were previously determined. MAH/Nb copolymerizations (3 mol % AIBN initiator, 60% solids in THF, 65°C, 24 h). Copolymerization data were collected via in situ FTIR to low degrees of conversion (∼ 10%) for copolymerizations of MAH and Nb. The following five different MAH/Nb comonomer feed molar ratios were analyzed: 40/60, 45/55, 50/50, 55/45, and 60/40. Conversion data that were measured with in situ FTIR were employed in the rearranged copolymer composition equation to estimate MAH and Nb reactivity ratios. Both of the reactivity ratios were determined to be near 0 (rMAH = 0.02, rNb = 0.01), which was indicative of an alternating copolymerization mechanism. The highest observed rate constant for copolymerization was obtained at an equal molar concentration of monomers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3240–3246, 2004

On modeling, identification, and control of a heavy-duty electrohydraulic harvester manipulator

Focuses on modeling, parameter estimation, and control for a heavy-duty electrohydraulic manipulator of a harvester machine. The linear-graph method is implemented in deriving mathematical models for the swing, boom and stick subsystems. Actuation dynamics are subsequently integrated with manipulator dynamics to result in a complete machine model. Identification procedures employed in estimating physical parameters are discussed in detail and key parameter results supplied. Model validation studies show good agreement between model predictions and experiments. A Cartesian controller for the motion of the manipulator end-point is described and response results are presented. It is shown that the obtained response is very good for the purposes of this harvester machine, resulting in very small relative tracking errors.

Quantitative imaging of 5-HT 1A receptor binding in healthy volunteers with [ 18f] p-MPPF

Animal experiments have shown that 4-(2′-methoxyphenyl)-1-[2′-( N-2′′-pyridinyl)- p-[ 18F]fluorobenzamido]ethylpiperazine ([ 18F] p-MPPF) can be used for 5-hydroxytryptamine 1A (5-HT 1A) receptor imaging. The aim of this study was to develop a method for the quantitative imaging of 5-HT 1A receptors in healthy volunteers with [ 18F] p-MPPF. After injection of [ 18F] p-MPPF radioactivity was rapidly taken up in the brain, with the highest accumulation in the medial temporal cortex. Low levels of radioactivity were found in cerebellum and basal ganglia. Plasma clearance and metabolism of [ 18F] p-MPPF resulted in only about 1% of the radioactivity in plasma as parent radioligand after 10 min. Using a linear graphical method (Logan-Patlak), binding potentials were calculated in several brain areas. A good correlation ( r = 0.95) was found between the obtained binding potentials and literature values for 5-HT 1A receptor densities. A good correlation ( r = 0.96) was also found between the body weight-corrected region/cerebellum ratios and the respective binding potentials. Moreover, a blocking experiment with pindolol (n = 3) showed a decrease of 40% in the region/cerebellum ratios of the target areas. Compared to those of [ carbonyl- 11C]WAY-100635, the binding potentials were four to six times lower, indicating that [ 18F] p-MPPF has a lower in vivo affinity for 5-HT 1A receptors. In conclusion, [ 18F] p-MPPF can be used for the quantitative analysis of 5-HT 1A receptor distribution in human brain.

Pharmacokinetics of radiotracers in human plasma during positron emission tomography.

Many radiopharmaceuticals for positron emission tomography (PET) are substantially metabolized in peripheral organs. Pharmacological treatments intended to alter cerebral metabolism might also alter radiotracer metabolism, consequently altering the cerebral uptake. First-order rate constants for the metabolism of PET tracers can be calculated by a linear graphical method from the precursor and metabolite concentrations measured in plasma extracts fractionated by HPLC. We tested the effects of specific pharmacological challenges on the plasma kinetics of six tracers used for PET studies of neurotransmission. The rate of O-methylation of circulating [(18)F]fluorodopa, a tracer of dopa decarboxylase activity in brain, was unaffected by pretreatment with amantadine, an antagonist of glutamate receptors. [(11)C]Deprenyl, a tracer of monoamine oxidase activity, was rapidly metabolized to [(11)C]methamphetamine and polar metabolites in healthy volunteers. The net rate constant of this metabolism was three times higher in a group of subjects under treatment for epilepsy, consistent with induction of hepatic microsomal enzymes by antiepileptic drugs. [(11)C]Sch 23390, a ligand for dopamine D1 receptors, was rapidly metabolized to polar metabolites. The net rate constant of metabolism was unaffected by pretreatment with lorazepam. [(11)C]-(S)-Nicotine, a ligand for nicotinic receptors, was rapidly metabolized to [(11)C]-(S)-cotenine, which is less polar than the parent compound. Pretreatment with mazindol, a dopamine uptake inhibitor, was without effect on peripheral metabolism of [(11)C]-(S)-nicotine. [(11)C]WIN 35,428, a tropane derivative which labels dopamine uptake sites, was metabolized to a nonpolar metabolite, but so slowly that the rate constant of this process could not be calculated. [(11)C]Raclopride, a ligand for dopamine D2 receptors, was first metabolized to a nonpolar metabolite, which then yielded two hydrophilic metabolites. The initial metabolic step was substantially blocked by pretreatment with amphetamine, possibly indicative of competitive inhibition of microsomal oxidation. Together, these results indicate that the linear graphic method is useful for estimating the kinetics of the plasma metabolism of many widely used PET tracers. Drug-drug interactions were revealed in subjects treated with specific pharmacological agents prior to tracer administration.