bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of glucose concentration in aqueous solution using FT NIR spectroscopy
Authors: Rondonuwu F S , Setiawan A , Karwur F F 
Published: September 2019

Abstract
NIR spectroscopy is widely used due to its capability to measure a large number of solid and liquid samples, including water-soluble constituents. The measurements of glucose concentrations in aqueous solutions are useful to examine how low concentrations of glucose in water can be measured using near-infrared spectroscopy and its potential applications for non-invasive measurements of glucose level in the blood. This paper describes an alternative approach to the determination of glucose content in aqueous solutions below 1000 mg/dL using Fourier transform near-infrared spectroscopy. This technique has the advantage of being less intensive sample preparation and non-destructive. Glucose in aqueous solutions were carefully prepared with concentrations of 0 - 100 mg/dL at intervals of 5 mg/dL, 110 - 500 mg/dL at intervals of 10 mg/dL and 525 - 1000 mg/dL at intervals of 25 mg/dL. Thus, the total produces 81 samples of standard solutions for both calibration and validation sample sets. PLSR analysis to near-infrared spectra show that glucose content in aqueous solutions can be predicted accurately with a maximum deviation of 6 mg/dL, indicating that the near-infrared prediction model is sufficient to determine glucose content in the aqueous solutions below 1000 mg/dL. The ability of the NIR to detect glucose content below 1000 mg/dL is particularly important when designing a non-destructive glucose level measuring device using a near-infrared light source.
Physical and Mechanical Properties of Concrete Containing Green Mussel (Perna viridis) Shell Ash as an Admixture
Authors: Nabilah Ismail Nurul , Hazurina Othman Nor , Wan Inn Goh , Shabery Sainudin Muhammad 
Published: September 2019

Abstract
In line with the aim of applying green technology in construction for a sustainable living and environmental preservation, this study focused on the utilization of green mussel shells, which come from unmanaged aquaculture residues. The shell ashes is used as an admixture material in the concrete mix. Green mussel shell, which had undergone drying, crushing, grinding and sieving processes were added into the concrete mix at different percentages of 1%, 2%, 3% and 4%. The concrete specimens were water-cured for 7, 28 and 60 days with the target strength of 30MPa in the 28 days. This research also focused on material characterization in term of physical properties of the mussel shell ash. The physical properties of the mussel shell ash were determine by the specific gravity test, setting time analysis and the particle size distribution. Furthermore, workability of the wet concrete was verified by conducting the slump test. Testing of the compressive strength, tensile strength, and capillary absorption have been conducted on the hardened concrete that contained the mussel shell ash mix right after the 7, 28, and 60 curing days. The high calcium carbonate (CaCO3) content in the mussel shell served as filler within the pores of the hardened concrete. Furthermore, the concrete specimens containing the mussel shell ash (GMSA2) demonstrated higher compressive strengths when compared to the control specimens. Apart from supporting the sustainability concept, this research also concluded that the addition of the mussel shell ash has improved the mechanical properties of the hardened concrete.
Analysis of cycloid type vacuum compressors for water vapor compression systems at sub-atmospheric pressures
Authors: Moesch T W , Janitschke T , Thomas C , Hesse U 
Published: September 2019

Abstract
Current refrigerant regulations lead to a transition towards low GWP refrigerants and natural refrigerants. Water vapor (R718) has been introduced in different vapor compression chiller and heat pump systems. Current R718 systems are based on turbo type compressors due to the resulting sub-atmospheric operating pressure and the low volumetric cooling capacity. This leads to a rather limited application range due to the pressure ratio limitations of turbo compressors. The application range of R718 may be extended towards heat pump operation by using positive displacement compressors such as state of the art vacuum compressors. This paper analyses the application of an oil free cycloid type variable pitch screw vacuum compressor for a heat pump at 2…15 °C evaporation temperature and 25…85 °C condensing temperature. A chamber model was used for the compressor analysis. During the analysis the compressor geometry, its speed and leakage gap sizes were varied. The results include the compressor isentropic efficiency, its volumetric efficiency and the resulting discharge temperature.
Development and Design of Energy Efficient Oil-Flooded Screw Compressors
Authors: Abdan S , Basha N , Kovacevic A , Stosic N , Birari A , Asati N 
Published: September 2019

Abstract
It is estimated that about 17% of the world’s generated power is used for compression. Thus all, even minor improvement of the efficiency of compressors will substantially reduce CO2 emission. This paper presents development of family of energy efficient oil-flooded screw compressors for Kirloskar Pneumatic Company Ltd. The developmental techniques adopted to improve efficiency such as introduction of superior ‘N’ rotor profile, rotor clearance management, performance calculation using 3D CCM (Computational Continuum Mechanics), direct parametric interface to CAD (Computer Aided Design), which contains bearing selection for complete 3D solid modelling. Also, contemporary prototyping and experimental investigation is supported by the fully computerised data acquisition and processing. The cumulative improvement of all these elements of the design process resulted in a very efficient machine which guarantees the competitive position of Kirloskar Pneumatic Company Limited in the screw compressor market.
Improving start up performance of single speed compressors by stator winding design
Authors: Cetinturk Tugba 
Published: September 2019

Abstract
Some east countries have line voltage fluctuations and voltage drops which can cause cooling problems on refrigerators because compressors cannot start up at these low line voltages. That’s why not only COP, but also start up performance at low voltages is critical on single speed compressors. Torque-speed curves of single speed asynchronous motors are so critical for compressor start up performance which takes form by motor design. Depending on compressor mechanical efficiency and shaft power needed, the asynchronous motor winding design should be fine-tuned and torque speed curve should be adjusted for start up properly at low voltage values. Even when the start torque at 0 rpm and breakdown torque values are high enough to provide low voltage compressor starting, instant torque decreases along the curve negatively effects start up performance. This study analyses torque-speed curve characteristics of asynchronous motors and determines stator winding design methods to improve compressor start up performance. The findings are also validated with motor and compressor test results.
Investigation of Discharge Flow and Force Coefficients in Hermetic Reciprocating Compressors
Authors: Sahin Caglar , Kerpicci Hμsnμ , Yasin Karabay Ahmet , Karahan Kerem 
Published: September 2019

Abstract
Low energy consuming products are eternal target of all household appliance manufacturers. To acquire desired energy index, high efficiency variable capacity compressors have started to be used widely on refrigerators. Reed valves and valve plate designs are the most critical issues in the development of reciprocating compressors in terms of coefficient of performance (COP). The stiffness of the reed valves and the port geometries play an important role on reducing the losses at various speeds and operating conditions. In the last decade, Fluid-Structure Interaction (FSI) method has started to be used in order to investigate valve dynamics. Because of the complexity and high computational cost of FSI method, system simulation tools are still preferred for faster and simpler solutions.
In-house developed simulation tool uses flow and force coefficients to calculate valve dynamics and mass flow rate. Those are calculated with the Computational Fluid Dynamics (CFD) analyses with respect to the valve lift. In the present study, flow and force coefficients at different piston positions were investigated. Piston pin which is used to reduce dead volume was also considered as a parameter. CFD calculations were established for steady state conditions at different valve positions with Ansys Fluent. The calculated flow and force coefficients were implemented into the simulation tool and the effect of piston position was presented in terms of COP, cooling capacity and compared with the experimental results.
Wavy plates as impinging oil separating structure at compressor discharge
Authors: Xu Jiu , Hrnjak Pega 
Published: September 2019

Abstract
Oil separation is commonly needed in air conditioning and refrigeration systems to reduce the oil circulation rate and keep the oil inside the compressor. For compactness, the oil separation structure integrated into the compressor is more and more popular than traditional external oil separators. This paper presents the impinging separation mechanism, one of the basic mechanisms of droplet separation. As a representative of the impinging separator, wave-plates structures are studied by flow visualization and experimental measurement under realistic compressor discharge conditions. The video of oil mist flowing through the baffles and plates is captured by a high-speed camera and analyzed quantitatively. The effect of the oil flow condition and the effect of separator geometry design are investigated based on the experimental data. With the help of flow visualization, the flow details are analyzed.
Experimental characteristic simulation for two-stage pipeline centrifugal compressor
Authors: Borovkov A I , Voinov I B , Galerkin Yu B , Drozdov A A , Soldatova K V 
Published: September 2019

Abstract
Up to now, the design methods for centrifugal compressors have been based on results of physical experiments. The possibility of correct CFD calculation of centrifugal compressors gas-dynamic characteristics could fundamentally change the situation. Gas-dynamic projects will become more reliable, cheaper, and the performance of compressors will be improved. However, the problem has not been solved yet. The experience of various authors shows that CFD calculations in many cases do not align well with experimentally obtained data. The aim of this paper is to check whether the commercial CFD software is capable of simulating centrifugal compressor characteristics using a 16 MW pipeline two-stage compressor as an example. The calculated characteristics of pressure ratio, efficiency and head coefficient are compared with characteristics measured using the manufacturer test bench on air. The calculations are performed in two ways: in the first case the flow in the impeller-stator gaps is taken into consideration, and in the second one it is not. In the first case, we do not take into account friction losses of the outer surfaces of impeller shrouds and leakage through labyrinth seals. The interface “STAGE” averages the parameters of flow at the impeller outlet and vaneless diffuser inlet. The flow leaving the impeller is averaged in tangential direction. This way of calculation excludes the mixing process of high and low-energy flow zones at the exit of the impeller. The calculated characteristic configurations are similar to the experimental ones, but they are shifted to the area of higher flow rates, and the difference in pressure ratio is out of the limits acceptable for engineering and research. Calculations that take into consideration gap losses underestimate the maximum efficiency by up to 2.5%. The characteristics calculated without gap losses are closer to the experimental characteristics. However, it is hardly possible to use this circumstance as a recommendation for the simulation methodology. The problem needs further investigation.
Implementation of scroll compressors into the Cordier diagram
Authors: Thomas C , Margraf M , Stoeckel C , Klotsche K , Hesse U 
Published: September 2019

Abstract
Selecting the most suitable machine type for a specific compression task is an essential step to ensure a reliable and economical operation of the overall system. For this, the eligibility of a compression principle can be estimated by the enhanced Cordier diagram by Grabow based on only a few input parameters (specific isentropic work, flow rate, speed and characteristic diameter). The working principle of scroll machines is known for more than one century. However, only the improvements in manufacturing processes during the last decades allowed their utilisation and a significantly increasing interest in scrolls in more and more fields of applications can be seen. Unfortunately, the scroll machine has not yet been introduced to the Cordier diagram.
Therefore, this paper shows a method for determining the characteristic key figures for different given scroll geometries. Based on this, it is shown how to implement scroll compressors into the Cordier diagram, i.e. different designs are analysed and the resulting data points are introduced to the diagram.
Friction and leakage analysis of the blocker-type valve designed for a revolving vane expander
Authors: Naseri Ali , Norris Stuart , Subiantoro Alison 
Published: September 2019

Abstract
Friction and leakage are two known issues that contribute to inefficiencies of rotary vane machines, and the Revolving Vane (RV) mechanism was introduced to reduce them. When used as an expander, a mechanism to determine the timing of the suction process in RV machine is required. In this study, a blocker-type valve is proposed for the suction control, and a simulation is carried out to investigate its friction and leakage characteristics. The valve comprises a stationary blocker that blocks high-pressure working fluid from entering the working chambers during expansion. In order to reduce friction, there should be a clearance between the rotary parts and the stationary blocker, which inevitably causes leakage of the working fluid into the working chambers. The leakage was modelled as a compressible flow through a convergent nozzle followed by a Fanno flow through an adiabatic constant cross-section channel. The results showed that the amount of leakage in the absence of lubricants is almost higher than ideal expander flow rate. However, this leakage demonstrated a positive contribution to the output torque as the results of the cylinder wall shear stress. The results suggested the importance of using lubricants in this valve design.
Factors Associated with Establishment and Growth of Pinus coulteri and Pinus sabiniana in California’s Central Coast Bioregion
Authors: Davis Thomas Seth , Redmond Miranda D , Foote Nathaniel E , Miller William 
Published: September 2019

Abstract
Forest inventory indicated recent decline in a P. coulteri population at its northern extent but live stems in sympatric P. sabiniana increased. Patterns of cone production, localized factors associated with regeneration, relations between wildfire and tree age distributions, and correlations between climate, seedling establishment, and tree growth were analyzed as potential mechanisms underlying unequal demographics between the two species. Four findings emerged: (1) P. sabiniana had a higher frequency of open cones at the time of observation, but cone production was size-biased, and cone production rates were similar for both species; (2) P. sabiniana seedlings were associated with a higher proportion of bare ground cover and westerly aspects, whereas establishment of P. coulteri seedlings was correlated with warm growing seasons and high vapor-pressure deficits, and seedlings occurred on northernly aspects; (3) age distributions of stands inside and outside a wildfire perimeter did not differ for either species, but annual growth increments of P. coulteri were greater within the fire perimeter; and (4) P. coulteri was even-aged, establishment was episodic, and occurred approximately 10 years post-wildfire. In contrast, the age distribution of P. sabiniana was highly variable, consistent with continuous recruitment, and establishment was not correlated with a climate signal.
Authoritarian Audiences, Rhetoric, and Propaganda in International Crises: Evidence from China
Authors: Weiss Jessica Chen , Dafoe Allan 
Published: September 2019

AbstractHow do government rhetoric and propaganda affect mass reactions in international crises? Using two scenario-based survey experiments in China, one hypothetical and one that selectively reminds respondents of recent events, we assess how government statements and propaganda impact Chinese citizens’ approval of their government's performance in its territorial and maritime disputes. We find evidence that citizens disapprove more of inaction after explicit threats to use force, suggesting that leaders can face public opinion costs akin to audience costs in an authoritarian setting. However, we also find evidence that citizens approve of bluster—vague and ultimately empty threats—suggesting that talking tough can provide benefits, even in the absence of tough action. In addition, narratives that invoke future success to justify present restraint increase approval, along with frames that emphasize a shared history of injustice at the hands of foreign powers.
2018 Highlights of Urban Entomology
Authors: Gondhalekar Ameya D 
Published: September 2019

Abstract
The field of urban entomology is primarily associated with the study of ants, bed bugs, cockroaches, termites, and other occasional invader pests that are found within or near human-made structures. A wide array of peer-reviewed studies were published in 2018. The topics of these articles ranged from genomes and basic biology of urban insects to various applied aspects of pest management. Key findings of these papers are presented and discussed from the perspective of the contributions they make to the discipline of urban entomology. Additionally, potential future research opportunities that are evident from these publications have been outlined.
Distinct polysaccharide growth profiles of human intestinalPrevotella copriisolates
Authors: Fehlner-Peach Hannah , Magnabosco Cara , Raghavan Varsha , Scher Jose U. , Tett Adrian , Cox Laura M. , Gottsegen Claire , Watters Aaron , Wiltshire-Gordon John D. , Segata Nicola , Bonneau Richard , Littman Dan R. 
Published: September 2019

SummaryThe gut-dwellingPrevotella copri, the most prevalentPrevotellaspecies in human gut, have been associated with diet as well as disease, but our understanding of their diversity and functional roles remains rudimentary, as studies have been limited to 16S and metagenomic surveys and experiments using a single type strain. Here, we describe the genomic diversity of 83P. copriisolates from 11 donors. We demonstrate that genomically distinct isolates, which can be categorized into differentP. copricomplex clades, utilize defined sets of plant polysaccharides that can be predicted in part from their genomes and from metagenomic data. This study thus reveals both genomic and functional differences in polysaccharide utilization between several novel human intestinalP. copristrains.
Perceptual learning of lesions in mammograms induced by response feedback during training
Authors: Frank Sebastian M. , Qi Andrea , Ravasio Daniela , Sasaki Yuka , Rosen Eric , Watanabe Takeo 
Published: September 2019

AbstractDetecting subtle lesions in mammograms indicative of early breast cancer usually requires years of experience. Well-designed training paradigms could be a strong tool for promoting perceptual learning (PL) with rapid and long-lasting improvement in detectability of these subtle mammographic lesions. Given that PL occurs without feedback about the accuracy of subjects’ responses, the role of feedback has been completely ignored in clinical applications of PL. However, in this study, we found that the contents of the feedback profoundly and differentially influence the formation and retention of PL to detect calcification and architectural distortion lesions, two types of mammographic lesions that are frequently missed in mammographic screenings. We trained subjects to detect one type of lesion in a mammogram and manipulated the content of the response feedback during training for 3 groups (no feedback, correctness only, and both correctness and location of the lesion). We found that PL occurred for both lesions when both correctness and location feedback were provided. PL also occurred for calcifications but not for distortions when only correctness was provided. No learning occurred without feedback for either lesion. A retest conducted six months later showed that PL was retained only in the group with both correctness and location feedback for both types of lesions. In contrast to the general consensus of basic PL studies, our results demonstrate that the content of the response feedback is a determining factor in forming and retaining PL to detect mammographic lesions.
Cis-Regulatory Accessibility Directs Muller Glial Development and Regenerative Capacity
Authors: VandenBosch Leah S. , Wohl Stefanie G. , Wilken Matthew S. , Cox Kristen , Chipman Laura , Reh Thomas A. 
Published: September 2019

AbstractDiseases and damage to the retina lead to losses in retinal neurons and eventual visual impairment. Although the mammalian retina has no inherent regenerative capabilities, fish have robust regeneration from Müller glia (MG). Recently, we have shown that driving expression of Ascl1 in adult mouse MG stimulates neurogenesis similar to fish regeneration. The regeneration observed in the mouse is limited in the variety of neurons that can be derived from MG; Ascl1-expressing MG primarily generate bipolar cells. To better understand the limits of MG-based regeneration in mouse retinas, we used ATAC- and RNA-seq to compare newborn progenitors with MG. Our analysis demonstrated striking similarities between MG and progenitors, with losses in regulatory motifs for neurogenesis genes. Young MG were found to have intermediate expression profiles and accessible DNA, which is mirrored in the ability of Ascl1 to direct bipolar neurogenesis in young MG. When comparing what makes bipolar and photoreceptor cells distinct from glial cells, we find that bipolar-specific accessible regions are more frequently linked to bHLH motifs and Ascl1 binding, indicating that Ascl1 preferentially binds to bipolar regions. Overall, our analysis indicates a loss of neurogenic gene expression and motif accessibility during glial maturation that may prevent efficient reprogramming.