Experimental Investigation of a Walk-in Refrigerator Performance Using R290 as a Retrofit for R22

A. R. El-Sayed,M. El Morsi,N. A. Mahmoud 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.4

An experimental performance study is performed on a refrigeration system equipped with a scroll compressor and tested with R22 using an electronic expansion valve (EEV) as an expansion device and controlled by proportional-integral-derivative (PID) control method. The system is tested at −12∘C, −8∘C, −4∘C, 0∘C and 4∘C evaporator air temperature and 20∘C, 25∘C and 30∘C condenser inlet water temperature at 50 Hz compressor driving frequency and 50Hz evaporator fans driving frequency. R22 reached the set point at all temperatures except −12∘C evaporator temperature with 30∘C condenser temperature due to the severe increase in the compressor discharge temperature that could result in the lubricating oil burnout. Then, the system is retrofitted with a reciprocating compressor especially designed to be used with R290 and tested with R290 at the same evaporator and condenser temperatures using EEV as an expansion device. R290 reached all set points at all evaporator and condenser temperatures. Also, R290 was able to reach all evaporator temperatures at higher condenser temperatures, 35∘C and 40∘C, and this will be discussed in future work. The results show that using R290, the pulldown time decreases by 30.3–71.4%, the ON time ratio decreases by 1–23.6%, the compressor discharge temperature decreases by 46.6–81∘C, the refrigerant mass flow rate decreases by 28.8–50.4%, VRC decreases by 15.2–32.5%, the compressor power consumption decreases by 34.4–44.3% and coefficient of performance (COP) increases by 35–115.5%.

Search for a very light NMSSM Higgs boson produced in decays of the 125 GeV scalar boson and decaying into τ leptons in pp collisions at s = 8 $$ \sqrt{s}=8 $$ TeV

Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Brondolin, E.,Dragicevic, M.,Erö,, J.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C. Springer-Verlag 2016 Journal of high energy physics Vol.2016 No.1

<P>A search for a very light Higgs boson decaying into a pair of tau leptons is presented within the framework of the next-to-minimal supersymmetric standard model. This search is based on a data set corresponding to an integrated luminosity of 19.7 fb(-1) of proton-proton collisions collected by the CMS experiment at a centre-of-mass energy of 8 TeV. The signal is defined by the production of either of the two lightest scalars, h(1) or h(2), via gluon-gluon fusion and subsequent decay into a pair of the lightest Higgs bosons, a(1) or h(1). The h(1) or h(2) boson is identified with the observed state at a mass of 125 GeV. The analysis searches for decays of the a(1) (h(1)) states into pairs of tau leptons and covers a mass range for the a(1) (h(1)) boson of 4 to 8 GeV. The search reveals no significant excess in data above standard model background expectations, and an upper limit is set on the signal production cross section times branching fraction as a function of the a(1) (h(1)) boson mass. The 95% confidence level limit ranges from 4.5 pb at m(a1) (m(h1)) = 8 GeV to 10.3 pb at m(a1) (m(h1)) = 5 GeV.</P>

Solvothermal synthesis of high-performance Ni-Co layered double hydroxide nanofoam electrode for electrochemical energy storage

Patel, R.,Inamdar, A.I.,Hou, B.,Cha, S.,Ansari, A.T.,Gunjakar, J.L.,Im, H.,Kim, H. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.4

<P>A nanofoam nickel cobalt layered double hydroxide (NiCo(OH)(2)) electrode film is fabricated on a stainless-steel substrate with the use of a simple one-step solvothermal process. The nanofoam NiCo(OH)(2) electrode exhibits a high specific capacitance of 2710.2 Fig at a current density.of 9.1 A/g, and a good capacity retention of similar to 70% after 2000 charge-discharge cycles at a high current density of 31.8 A/g. An energy density of 60.23 Wh/kg is obtained at a power density of 1.8 kW/kg. The excellent electrochemical energy storage performance of the NiCo(OH)(2) electrode is due to the synergetic effect of a significantly improved ionic diffusion and an effective charge transfer, which is linked to a well-dispersed interconnected nanofoam morphology and binder-free direct contact with the current collector. (C) 2017 Elsevier B.V. All rights reserved.</P>

$n$-weak amenability and strong double limit property

A.R. Medghalchi,T. Yazdanpanah 대한수학회 2005 대한수학회보 Vol.42 No.2

Let {mathcal A} be a Banach algebra, we say that {mathcalA}has the strongly double limit property (SDLP) if for each boundednet (a_{alpha}) in {mathcal A} and each bounded net(a^*_{beta}) in {mathcal A}^*, lim_{alpha}lim_{beta}leftlangle a_{alpha} , a^*_{beta}rightrangle = lim_{beta} lim_{alpha} leftlangle a_{alpha}, a^*_{beta} rightrangle whenever both iterated limits exist. In this paperamong other results we show that if {mathcal A} has the SDLP and{mathcal A}^{**} is (n-2)-weakly amenable, then {mathcal A} isn-weakly amenable. In particular, it is shown that if {mathcalA}^{**} is weakly amenable and {mathcal A} has the SDLP, then ${\mathcal A}$ is weakly amenable

A CLASS OF MAPPINGS BETWEEN R_z-SUPERCONTINUOUS FUNCTIONS AND R_δ-SUPERCONTINUOUS FUNCTIONS

Prasannan, A.R.,Aggarwal, Jeetendra,Das, A.K.,Biswas, Jayanta The Honam Mathematical Society 2017 호남수학학술지 Vol.39 No.4

A new class of functions called $R_{\theta}$-supercontinuous functions is introduced. Their basic properties are studied and their place in the hierarchy of strong variants of continuity, which already exist in the literature, is elaborated. The class of $R_{\theta}$-supercontinuous functions properly contains the class of $R_z$-supercontinuous functions [39] which in turn properly contains the class of $R_{cl}$-supercontinuous functions [43] and so includes all cl-supercontinuous (clopen continuous) functions ([38], [34]) and is properly contained in the class of $R_{\delta}$-supercontinuous functions [24].

간호대생과 의대생의 간호사 이미지 비교

구민진,김수영,방정민,서아영,양희진,윤소람,이윤재,이재은,이지연,정윤경,최수정 이화여자대학교 간호과학대학 2014 이화간호학회지 Vol.- No.48

Purpose: This study aims to analyze the difference in the perception that nursing students and medical students have regarding the image of nurses. Method: The sampling group for this study was made up of 111 nursing students and 117 medicine students, conducted from the 19th August 2013 to 3rd September 2013. The tool used for this study is the “Nurse Image Scale”. The data is analyzed using the SPSS 21.0 program, technical stats, t-test and ANOVA with Scheffe test. Result: There was a notable difference in the results(t=6.94, p<001), with the average image perception score of nurses at 3.84±0.34 amongst nursing students being higher than the 3.50±0.38 amongst Medicine students. The average score of the 4 areas tested, “Qualification of a Nurse”, “Role of a Nurse”, “Social Participation of a Nurse” and “Interpersonal Skills of a Nurse” were all marked higher by the nursing students than the medicine students. The average score became notably higher as the period of practice became shorter with nursing students (F=4.21, p=.043). Furthermore, the average score for the “Qualification of a Nurse” was notably higher as the period of practice became shorter (F=3.98, p=.049). Medical students gave an average score for the “Qualification of a Nurse”(F=3.72, p=.027) and the “Interpersonal Skills of a Nurse”(F=4.11, p=.019) which was relative to the development of a nurse’s image, while the average score for the “Role of a Nurse” was notably higher with a longer period of practice(F=6.65, p=.011). Conclusion: The results of this study suggest that the image perception of a nurse can vary depending on the experience in period of practice. Therefore, together with this study conducted with nursing students and medicine students, there is a need for further studies conducted on image perception of nurses with various experience in period of practice.

Novel Atomizing Novel for Domestic Household Aerosols

( R. A Sharief ) 한국액체미립화학회 2010 한국액체미립화학회 학술강연회 논문집 Vol.2010 No.-

With increasing legislation on volatile-organic-compounds, there is interest in either reducing the hydrocarbon content in aerosol cans or removing it completely, i.e. using inert compressed gas propellant. However both these approaches give relatively poor atomisation unless improvements in atomisation performance are made. This paper describes experiments that have been carried out to explore the effects of flow control devices on the flashing flow and the quality of the spray and which are leading to new generation of household aerosols. Domestic aerosols such as air fresheners and body sprays are commonly used all over the world. Aerosols generally consist of a pressurised canister containing a product and a liquified volatile propellant. The aerosols work consistently using the same principle; where the product and the propellant are actuated through a simple nozzle. Flash atomization of the propellant takes place to break up the product into a cloud of droplets This paper is related to an innovation patents WO2005005053 (A1) and WO2005005055 (A1),WO2007015062 (A1) (1, 2, 3 and 4) The aims of this investigation are, to develop improved, aerosol actuators using a new manufacturing technology, to reduce VOC content of existing aerosol cans, e.g. butane reduction and ethanol replacement by water, to achieve spray performance at least matching the characteristics of existing aerosol air fresheners, and body sprays, to gain improved understanding of internal flashing flows. More advanced designs of actuators have been made depending on the inventions related to shape chambers, multiple passages of flow and throttles. It is now possible to manufacture household can aerosols such as air fresheners, body sprays and hair sprays with massive reduction in hydrocarbons or volatile organic compounds (VOC). Internal features of Raj designs and the cyclonic device have developed for spraying air fresheners and other viscous and none viscous products, below results show a matched droplet size of the market nozzle, market propellant cans with an improved spray angle and spray penetration length. It has been found that droplet size produced at the outlet orifice of a nozzle can be controlled by incorporating a number of different control features into the fluids flow passageway between the inlet and the outlet which modify the characteristics of the fluid as it flows through the passageway for example it has been found to be particularly beneficial to form two or more expansion chambers along the fluids passageway, each chamber having a constricted inlet opening arranged so that the fluids is sprayed into the chamber. By use of internal shaped chambers and channels in the spray nozzle the spray quality can be improved. By changing the geometry of the external exit of the nozzle spray, an improvement can be achieved. More complex designs of household aerosol can actuators have been made possible by using a new manufacturing technology. This has made feasible the use of various flow control devices and multiple orifice actuators, with no cost penalty. An experimental research programme has systematically applied these flow control devices in specially made actuator models for the cases of spraying those very different types of products, body spary and air-freshener. The experiments have shown that these flow control devices permit control of droplet size, control of flow rate, spray pattern manipulation, the production of narrower droplet size distributions, and reduction of can VOC content. From the experiments carried out by Raj Designs on several products, it has proven that great improvements on reduction of drop sizes and crucial reduction on inhalables by keeping the flow rate the same with comparison to the original cap

MOA-2010-BLG-073L: AN M-DWARF WITH A SUBSTELLAR COMPANION AT THE PLANET/BROWN DWARF BOUNDARY

Street, R. A.,Choi, J.-Y.,Tsapras, Y.,Han, C.,Furusawa, K.,Hundertmark, M.,Gould, A.,Sumi, T.,Bond, I. A.,Wouters, D.,Zellem, R.,Udalski, A.,Snodgrass, C.,Horne, K.,Dominik, M.,Browne, P.,Kains, N.,Br IOP Publishing 2013 The Astrophysical journal Vol.763 No.1

<P>We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010 March 18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source light curve, we demonstrate that it is an irregular variable over timescales >200 days. Its dereddened color, (V - I)(S),(0), is 1.221 +/- 0.051 mag, and from our lens model we derive a source radius of 14.7 +/- 1.3 R-circle dot, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q = 0.0654 +/- 0.0006. The Einstein crossing time of the event, t(E) = 44.3 +/- 0.1 days, was sufficiently long that the light curve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, D-L = 2.8 +/- 0.4 kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with M-L,M-1 = 0.16 +/- 0.03 M-circle dot, while the companion has M-L,M-2 = 11.0 +/- 2.0 M-J, putting it in the boundary zone between planets and brown dwarfs.</P>

2G HTS wire with enhanced engineering current density attained through the deposition of HTS layer with increased thickness

Markelov, A.,Valikov, A.,Chepikov, V.,Petrzhik, A.,Massalimov, B.,Degtyarenko, P.,Uzkih, R.,Soldatenko, A.,Molodyk, A.,Sim, Kideok,Hwang, Soon The Korea Institute of Applied Superconductivity a 2019 한국초전도저온공학회논문지 Vol.21 No.4

2G HTS wire with high engineering current density is desired for applications where compact, high power density superconducting equipment is important. We have succeeded in enhancing engineering current density of commercial SuperOx 2G HTS wire based on GdBCO by increasing the HTS layer thickness without fast degradation of the HTS film microstructure. This was possible after improving the temperature uniformity along the HTS film deposition zone. In particular, the wire engineering current density was increased from 700-770 A/㎟ (for a 65 ㎛-thick wire without stabilisation) or 430-480 A/㎟ (for a 105 ㎛-thick stabilised wire) at the beginning of this study to almost 1200 A/㎟ (for a 67 ㎛-thick wire without stabilisation) or 770 A/㎟ (for a 107 ㎛-thick stabilised wire) at completion of this study.

Analysis method for determination of nisin A and nisin Z in cow milk by using liquid chromatography-tandem mass spectrometry

Ko, K.Y.,Park, S.R.,Lee, C.A.,Kim, M. American Dairy Science Association 2015 Journal of dairy science Vol.98 No.3

Nisin, a polypeptide with antimicrobial properties, is known as a natural preservative. It is used in various foods, including dairy products. This study validated a novel procedure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of nisin A and nisin Z in cow milk. An extraction solution of 0.1 M acetate buffer containing 1 M NaCl (pH 2.0) and MeOH (1:1) was used to extract nisin A and nisin Z from milk samples. After the addition of extraction buffers, the samples were homogenized and centrifuged. The supernatant was filtered and injected for LC-MS/MS analysis. The linearity of the analytical method had a high correlation coefficient (r≥0.9987). The limits of quantitation of nisin A and nisin Z were approximately 12.9 and 10.9 @?g/kg, respectively. The accuracy of the analytical method in milk ranged from 90.6 to 103.4% for nisin A and from 83.8 to 104.4% for nisin Z. The coefficient of variation values of intra- and interday in milk determined to be less than 5% in both nisin A and nisin Z. Because the proposed method has comparatively high recovery and low coefficient of variation, it seems appropriate for the determination of nisin A and nisin Z in milk samples. As the quantification of nisin A and nisin Z in milk samples by using LC-MS/MS has only been rarely reported until now, this study provides a meaningful technological advance for the dairy industry.