bluuebunny/crossref_metadata_2025_split huggingface dataset:
Empirical performance of GARCH, GARCH-M, GJR-GARCH and log-GARCH models for returns volatility
Authors: Nugroho D B , Kurniawati D , Panjaitan L P , Kholil Z , Susanto B , Sasongko L R 
Published: September 2019

Abstract
Volatility plays an important role in the field of financial econometrics as one of the risk indicators. Many various models address the problem of modeling the volatilities of financial asset returns. This study provides a new empirical performance comparison of the four different GARCH-type models, namely GARCH, GARCH-M, GJR-GARCH, and log-GARCH models based on simulated data and real data such as the DJIA, S&P 500, and S&P CNX Nifty indices on a daily period from January 2000 to December 2017. We also investigate the estimation results obtained using Solver’Excel and verify those results against the results obtained using a Markov chain Monte Carlo method. The simulation study showed that the GARCH model is outperformed by other models. Meanwhile, the empirical study provides evidence that the GJR-GARCH model provides the best fitting, followed by the GARCH-M, GARCH, and log-GARCH models. Furthermore, this study recommends the use of Excel’s Solver in practice when the parameter estimates for GARCH-type model do not close to zero.
Synthesis of ZnO-gold nanoparticles composite using Hibiscus sabdariffa extract as reductor
Authors: Alfanaar R , Elim P E , Kesuma R F , Monica E 
Published: September 2019

Abstract
One of the synthesis methods currently being carried out is green synthesis. One of the efforts to implement the green method is to use plant extracts that can be renewed. Hibiscus sabdariffa is one type of plant that is able to produce anthocyanin pigments. In this study, the synthesis of ZnO composites with gold nanoparticles will be carried out using Hibiscus sabdariffa flower extract. The composites of gold nanoparticles and ZnO were determined using XRD instrumentation where there were characteristic peaks of ZnO and gold nanoparticles.
On dynamic optimization sensitivity analysis
Authors: Hartono  
Published: September 2019

Abstract
This article describes a linear penalty method for getting sensitive information, i.e. the effect of variation on the constraint to the objective function. The dynamic optimization problem discussed here is a problem with state constraints. At first, the problem is formulated to unconstrained dynamic optimization problem by adding the constraints to the objective function as linear penalty terms. Then, the mathematical formulas to evaluate the change in the objective function and the optimal solution are derived if small perturbation introduced in the constraints. Lastly, the formulas are applied to some numerical examples. Comparison the result of numerical simulations to the numerical solutions obtained from reliable software, i.e. MISER 3.3, shows that the method in general is quite effective. The differences between two solutions are very small and insignificant.
Effectiveness of Non-monitored Green Roofs for Stormwater Management
Authors: Kasmin Hartini , Khalisha Khalidan Siti , Afnizan Wan Mohamed Wan , Syafira Razak Nur , Yacob Mohamad Norfekry Md. 
Published: September 2019

Abstract
A green roof is an alternative roofing system of any building or house that provides a better environment for urban areas. It has the potential to mitigate urban water problems. This study aims to investigate the rainfall runoff performance of two non-monitored green roofs with two different slopes. The experiment uses two types of non-monitored green roofs, namely flat roofs and sloped roofs that were exposed to climatic conditions in Parit Raja. The physical characteristics of the roofs were observed and rainfall runoff data was collected. The results showed that when 4 L of water was manually poured onto the roofs, an average of 60.4% of water was retained on sloped roofs whereas 48.4% was retained on flat roofs. Based on the 5-minute interval data, the retention ranges between 55.6% and 71.2% for both roofs. In terms of daily rainfall for a week, the average percentage was 69.2% for sloped roofs and 70.6% for flat roofs. All three approaches show that the green roofs produced less water runoff compared to normal roofs with both slopes retained water efficiently. Therefore, rainfall runoff performance for two types of green roof slopes was investigated and the available storage for the green roofs was recorded. In conclusion, with little maintenance, non-monitored green roofs can be efficiently used as a water mitigation system for urban areas
Water Quality Classification Using an Artificial Neural Network (ANN)
Authors: Sulaiman Khadijah , Hakim Ismail Lokman , Adib Mohammad Razi Mohd , Shalahuddin Adnan Mohd , Ghazali Rozaida 
Published: September 2019

Abstract
Malaysia is currently a rapidly developing country to achieve a 2020 vision. However the development that has been carried out contributed to a negative impact on the environment especially on water quality. Due to the deterioration of water quality, serious management efforts on water quality has been taken. Thus, the aim of this study is to investigate a technique that can automatically classify the water quality. The technique is based on the concept of Artificial Neural Network (ANN). Since the greater part of their methodologies depend on the idea of `pattern recognition’. Thus, it is convenient to inspect its ability in classify water quality. There are six environmental data were used in this study such as pH, total suspended solids (TSS), dissolved oxygen (DO), chemical oxygen demand (COD), biological oxygen demand (BOD), and ammonia. The data was obtained by in-site measurement and laboratory analysis. Then, the data was used as the feeder of input variables in the ANN database system. After training and testing the network of ANN, the result showed that 80.0% of accuracy classification with 0.468 of root mean square error (RMSE). This showed the encouraging results for classification.
Home Water Purification System in Malaysia: Qualitative and Quantitative Study
Authors: Shahirah Abd Rahim Nur , Othman Norzila 
Published: September 2019

Abstract
Concern over tap water quality has led to the expansion of water filtration system in Malaysia. This study is important to ensure that brands of water filters that have dominated the market in Malaysia do not exceed the quality of water released by safe water filters and no other pollutants leach from the machine. An exploratory study was undertaken to determine the pattern and selection factor of a home water filter system through a set of questionnaires. The survey results indicated that the most popular brands in Malaysia is Brand A from reverse osmosis filtration system. In the experimental study, five most frequently used brands of home water filters were evaluated and compared. Among the 27 parameters studied for each home water filter system, all parameter of physical, chemical and bacteriological quality is complied with the guideline values of the Ministry of Health Malaysia. Parameter of bacteriological quality shows absence bacteria parameter was detected in all samples tested. Meanwhile, physical quality parameter was given best performance removal from brand E and chemical water quality was efficient removal from brand C. In most cases user apply the home treatment of tap water to ensure that the quality of water physically look better and safe to be consumed.
Shear strength of FRP-Externally strengthened High Strength RC T-Beams
Authors: Ibrahim Basil , Leblouba Moussa , Al-Toubat Salah , Barakat Samer 
Published: September 2019

Abstract
This paper presents preliminary results of an extensive experimental program on the behavior of high-strength (HS) reinforced concrete (RC) T-beams strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets. The test program involves the fabrication and testing of 56 RC beams and many objectives to achieve. The objective of this paper is to investigate the effect of the number of CFRP layers on the shear strength of HS RC beams. To this end, three full-scale specimens were prepared and instrumented with displacement transducers and strain gauges: one control beam, one single-layer of CFRP sheets, and one double-layer of CFRP sheets. All beams were simply supported and subjected to a monotonically increasing load until failure. Preliminary results showed that in the absence of transverse steel reinforcements, the number of CFRP layers does not affect the ultimate strength of the HSC beams.
Calculation of clearances in twin screw compressors
Authors: Husak Ermin , Kovacevic Ahmed , Karabegovic Isak 
Published: September 2019

Abstract
Clearances between rotating and stationary parts in a screw compressor are set to ensure the efficient operation and allow for thermal deformation without unwanted contacts. The change in clearances is caused by both pressure and temperature changes within the machine. If clearances are too large, the increased leakage flows will reduce efficiency. However, if the nominal clearances are too small, contacts between the rotating and stationary parts can occur as a consequence of rotor and casing deformations. In order to determine the operational clearances, a numerical analysis of deformation of screw compressor rotors and casing has to be performed. This paper discusses how the temperature of rotor and casing surfaces calculated from the one-dimensional chamber model in the SCORG could be used as a boundary conditions for a steady state thermal and structural analysis of a screw compressor solid parts. Deformations of rotors and casing under temperature load were calculated using a commercial Finite Element Analysis code ANSYS. Operational clearance are estimated from these deformations and some recommendations for further work are proposed.
An improvement in the production flexibility and accuracy of rotor milling process employing Finger Cutters
Authors: Bergström A 
Published: September 2019

Abstract
Finger Cutters (FCs) are the recently SRM-developed rotor cutting technology which can be easily integrated into multi-axis flexible milling machines. Opposite to the traditional disc cutters, FC operates inside the rotor body and as a result of that requires much less torque. This opens a new possibility to utilize multi-axis machines in rotor milling process, bearing in mind that they generally have less torque than specialized milling machines. An introduction to FC technology including mathematical modeling, geometrical definition and cutter body grinding has been presented in ICSM2018 conference in Dortmund [2].
In this work, we will present the recent development in FC technology. In particular, we will focus on an innovative method to increase the production accuracy of the FC-cut rotor bodies. This method incorporates an iterative procedure of milling, measuring and adjusting. First, a theoretical target surface, so-called adjustment cut, is defined with a safety margin from the final finished surface. FC removes the material aiming to match the adjustment cut. Measuring the surface and comparing with the adjustment cut, a set of correction factors are calculated for the next iteration. Employing this iterative procedure, a notable improvement in the rotor manufacturing accuracy is achieved while risk for scrap rotors is reduced significantly.
Normal Rack Grid Generation Method for Screw Machines with Large Helix Angles
Authors: Yang Lu , Kovacevic Ahmed , Read Matthew 
Published: September 2019

Abstract
Improving the efficiency of the screw machine is highly significant for industry. Numerical simulation is an important tool in developing these machines. The 3D computational fluid dynamic simulation can give a valuable insight into the flow parameters of screw machines. However, it is currently difficult to generate high quality computational grids required for screw rotors with large helix angle. This is mainly due to the excessively high cell skewness of the rotors with large helix angel, which would introduce errors in numerical simulation. This paper presents a novel grid generation algorithm used for the screw rotors with large helix angel. This method is based on the principles developed for the grid generation in transverse cross-section. Such mesh is generated by SCORGTM using normal rack grid generation method which means numerical meshes are generated in a plane normal to the pitch helix line. The mesh lines are then parallel to the helix line and thus an orthogonal mesh will be produced. The main flow and leakage flow directions are orthogonal to the mesh, potentially reducing numerical diffusion. This developed algorithm could also be employed for single screw machines.
The development of the CS valve used to the variable swash plate compressor for a vehicle air-conditioning system
Authors: Taejin Le , Lee Bongsub , Lee Geonho , Kyeong-Ho Shin , Joo-Hyung Kim 
Published: September 2019

Abstract
Since the variable swash plate type compressor used in the vehicle air-conditioning system is mounted on the engine and uses the power of the vehicle, many studies have been conducted on improving the performance of the compressor in order to increase the fuel efficiency of the vehicle. This study was also carried to improve compressor performance through the control room & suction muffler (CS) valve which is an on-off valve located between the control room and suction muffler. The swash plate angle can be controlled by the control room pressure adjusted with control gas. The flow of control gas starts from compressed high-pressure gas which is in the discharge muffler, flows into the control room through the external control valve (ECV) and then flows out to suction muffler through the CS hole which is located between the control room and suction muffler. Such this control method is using the compressed discharge refrigerant so that the compressor power is increased when the amount of the control gas is increased. Therefore, in this study, the CS valve has been developed to reduce the compressor power by minimizing the amount of control gas and it has been confirmed that the compressor power was reduced about 5~10% by the compressor operation speed.
Study on the stress and deformation of a diaphragm compressor cylinder head under extreme conditions
Authors: Wang Ting , Tang Zhou , Jia Xiaohan 
Published: September 2019

Abstract
When a high-pressure diaphragm compressor applied in the hydrogen refueling station, the structure strength of the cylinder head are one of the most important evaluation criteria to guarantee the reliability and efficiency of the diaphragm compressor. Considering the thermal stress, this paper described a thermal-structural coupled analysis on the cylinder head of a diaphragm compressor, in which the thermal analysis was carried out, and then the structural analysis was performed based on temperature distribution. The stress and deformation of the cylinder head under high-temperature and high-pressure conditions were obtained. The experimental method was also conducted for the verification of thermal analysis. Results indicated that during the operation of the compressor, the temperature in the discharge holes was the highest, and the stress caused by high temperature and high working pressure in the discharge holes could reach a high level due to the restriction of the structure. As a result, the region where the discharge holes were opened on the cavity surface protruded into the diaphragm cavity, resulting in plastic deformation, and the plastic deformation would also result in hydrogen embrittlement, influencing the strength of the cylinder head.
Maritime security: the uncharted politics of the global sea
Authors: Bueger Christian , Edmunds Timothy , Ryan Barry J. 
Published: September 2019

Abstract
In this introduction to a special section of the September 2019 issue of International Affairs, we revisit the main themes and arguments of our article ‘Beyond seablindness: a new agenda for maritime security studies’, published in this journal in November 2017. We reiterate our call for more scholarly attention to be paid to the maritime environment in international relations and security studies. We argue that the contemporary maritime security agenda should be understood as an interlinked set of challenges of growing global, regional and national significance, and comprising issues of national, environmental, economic and human security. We suggest that maritime security is characterized by four main characteristics, including its interconnected nature, its transnationality, its liminality—in the sense of implicating both land and sea—and its national and institutional cross-jurisdictionality. Each of the five articles in the special section explores aspects of the contemporary maritime security agenda, including themes of geopolitics, international law, interconnectivity, maritime security governance and the changing spatial order at sea.
The oversecuritization of global health: changing the terms of debate
Authors: Wenham Clare 
Published: September 2019

Abstract
Linking health and security has become a mainstream approach to health policy issues over the past two decades. So much so that the discourse of global health security has become close to synonymous with global health, their meanings being considered almost interchangeable. While the debates surrounding the health–security nexus vary in levels of analysis from the global to the national to the individual, this article argues that the consideration of health as a security issue, and the ensuing path dependencies, have shifted in three ways. First, the concept has been broadened to the extent that a multitude of health issues (and others) are constructed as threats to health security. Second, securitizing health has moved beyond a rhetorical device to include the direct involvement of the security sector. Third, the performance of health security has become a security threat in itself. These considerations, the article argues, alter the remit of the global health security narrative; the global health community needs to recognize this shift and adapt its use of security-focused policies accordingly.
Antibacterial/Antifungal Activity of Extracted Chitosan From American Cockroach (Dictyoptera: Blattidae) and German Cockroach (Blattodea: Blattellidae)
Authors: Basseri Hamidreza , Bakhtiyari Ronak , Hashemi Sayed Jamal , Baniardelani Mojgan , Shahraki Hadi , Hosainpour Laila 
Published: September 2019

Abstract
We investigated bactericidal and fungicidal properties of chitosan extracted from adults and nymphs from both German cockroach, Blattella germanica (Blattodea: Blattellidae) and American cockroach, Periplaneta americana (Dictyoptera: Blattidae). The cuticle of adults and nymphs extracted from both cockroaches were dried and ground. The powders were demineralized and deproteinized followed by deacetylation using NaOH. Finally, the chitosan yields were examined for antibacterial and antifungal activities. The degree of deacetylation (DD) was different between adults and nymph stages. The antimicrobial effect of American cockroach chitosan (ACC) and German cockroach chitosan (GCC) was tested against four bacteria and four fungi. The extracted chitosans from American cockroach, Periplaneta americana and German Cockroach, Blattella germanica suppressed the growth of Gram-negative/positive bacteria except Micrococcus luteus. The growth of Aspergillus flavus and Aspergillus niger were notability inhibited by the extracted chitosans. The antimicrobial effect of the chitosan depended on the cockroach species, with chitosan of the American cockroach showing more inhibitory effect. This difference may be due to differences in the structure of chitin between the two cockroach species.
Highlights of Medical Entomology 2018: The Importance of Sustainable Surveillance of Vectors and Vector-Borne Pathogens
Authors: Connelly Roxanne 
Published: September 2019

Abstract
The theme of the 2018 Entomological Society of America, Entomological Society of Canada, and Entomological Society of British Columbia Joint Annual Meeting was Crossing Borders: Entomology in a Changing World. Following the theme of the meeting, papers selected for the 2018 ‘Highlights of Medical Entomology’ included reports of expanded ranges for Aedes albopictus (Skuse) (Diptera: Culicidae), Aedes japonicus japonicus (Theobald) (Diptera: Culicidae), Culex coronator Dyar and Knab (Diptera: Culicidae), Mansonia titillans (Walker) (Diptera: Culicidae), and Wyeomyia mitchellii (Theobald) (Diptera: Culicidae); a first report of mosquito feeding on earthworms and leeches; Cache Valley virus detection in Ae. j. japonicus; surveillance in high-risk areas of Canada for Lyme Disease; and increasing lone-star tick detections in Connecticut. The selection of papers served as a reminder of the increasingly difficult challenge of sustaining vector surveillance programs. Fluctuating funding and a decline in vector taxonomists and identification expertise contribute to the erosion of vector surveillance.
Interaction Between Psychiatric Symptoms and History of Mild TBI When Evaluating Postconcussion Syndrome in Veterans
Authors: Larsen Sadie E , Larson Eric R , Hunt Joshua C , Lorber William G , deRoon-Cassini Terri A 
Published: September 2019

Abstract
Introduction: Symptoms of postconcussive syndrome (PCS) after mild TBI (mTBI) have been shown to resolve quickly, yet new research raises questions about possible long-term effects of this condition. It is not clear how best to address assessment and treatment when someone reports lingering symptoms of PCS. One self-report measure used by the VA and the DoD is the Neurobehavioral Symptom Inventory (NSI), but this measure may be affected by underlying psychiatric symptoms. We investigated whether the NSI is sensitive to mTBI after considering a number of psychiatric and demographic factors. Methods: This study examined which factors are associated with NSI scores in a Veteran sample (n = 741) that had recently returned from deployment. Results: Post-traumatic stress disorder (PTSD) and depression accounted for most of the variance on the NSI. Although history of mTBI was initially related to NSI, this association was no longer significant after other covariates were considered. Conclusions: The NSI score was primarily explained by symptoms of PTSD and depression, suggesting that the NSI is not specific to the experience of a brain injury. We recommend cautious interpretation when this measure is used in the chronic phase after mTBI, especially among patients with comorbid depression or PTSD.