Geometric design and analysis of scroll compressors with a novel circular involute modified wrap

2021 ◽  
pp. 095440892110530
Author(s):  
Jun Wang ◽  
Yi Han ◽  
Zhoujin Xi ◽  
Zengli Wang ◽  
Dong Cui
Keyword(s):  
Compression Ratio ◽  
Geometric Model ◽  
Geometric Parameters ◽  
Circular Arc ◽  
Design Flexibility ◽  
Study Results ◽  
Temperature Load ◽  
Central Regions ◽  
Working Performance ◽  
And Performance

The scroll geometry in the central region of the scroll wrap plays a crucial role in determining the working performance of scroll compressors. In order to improve the comprehensive performance of scroll wraps, in this study, a novel circular involute modified wrap was put forward, in which the central and peripheral wrap profiles were connected by a circular involute in the central regions, so that a pair of fully smooth and correct meshing scroll wraps were generated. A geometric model of the involute modified wrap were proposed, and then equations of the wrap profiles and relations between geometric parameters were derived. Effects of geometric parameters on the shape and performance of the involute modified wrap were discussed in detail. Furthermore, the compression ratio of the involute modified wrap was studied by numerical simulation, and the deformation of the involute modified wrap produced by temperature load and pressure load was calculated, compared with the conventional circular arc modified wrap under the same geometric shape of scroll compressors. Study results demonstrate that the proposed involute modified wrap may simultaneously improve the compression ratio and the strength of wrap head for scroll compressors; in addition, the involute modified wrap is good for design flexibility, and therefore is superior to the circular arc modified wrap.

Geometric Design and Analysis of Novel Asymmetrical Rotors for Roots Vacuum Pumps

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Jun Wang ◽  
Shuran Yang ◽  
Rundong Sha ◽  
Hongxin Li ◽  
Chao Xu
Keyword(s):  
Geometric Design ◽  
Geometric Parameters ◽  
The Other ◽  
Design Flexibility ◽  
Circular Arcs ◽  
Study Results

Abstract Roots rotors dramatically determine the performance of Roots vacuum pumps. In order to develop new rotors with higher performance, a pair of novel asymmetrical rotors or eccentric involute rotors were proposed based on the conventional symmetrical involute rotors. Profiles of one rotor consist of four eccentric involutes and four circular arcs; profiles of the other rotor consist of four conjugate curves of eccentric involutes and four circular arcs. A model of the proposed asymmetrical rotors was established, and effects of geometric parameters on the area-utilizing ratio of rotors were analyzed. The study results show that the proposed asymmetrical rotors have more number of independent geometric parameters than the conventional rotors of Roots vacuum pumps, so that the asymmetrical rotors are superior to the conventional rotors in terms of design flexibility. The contents of this study can be applied in the design of Roots vacuum pumps.

Effect of health education on awareness and practices of breast self-examination among females attending a charitable hospital at North Karachi

2021 ◽  
Vol 71 (9) ◽  
Author(s):  
Zohra Jabeen ◽  
Nighat Shah ◽  
Zaeema Ahmer ◽  
Sulhera Khan ◽  
Amir Hussain Khan ◽  
...  
Keyword(s):  
Health Education ◽  
Intervention Group ◽  
Positive Association ◽  
Control Group ◽  
Low Resource ◽  
Resource Setting ◽  
Low Resource Setting ◽  
Study Results ◽  
Quasi Experimental ◽  
And Performance

Abstract Objective: The objective of this study was to compare the effectiveness of health education as an intervention to promote BSE among intervention and non-intervention group presenting in a low resource setting at North Karachi Methodology: This Quasi-experimental study was conducted from January-August 2018 in a charitable hospital in Karachi after taking ethical approval by the Institutional Review Board of Jinnah Sindh Medical University and relevant approvals from the hospital authorities. This study recruited 172 eligible women by dividing them into intervention (n=86) and control (n=86) groups from a low resource setting in Karachi. Demographic variables were collected through pretested questionnaire by interview. Intervention group then received health education regarding carcinoma of breast, importance of BSE and monthly motivation to perform BSE through cell phone. The questionnaire was again filled after 6 months of intervention. Control group was also given health education sessions upon completion of study. Results: Results revealed that both groups were similar initially. After 6 months females in intervention group showed significant (p=<0.001) improvement in knowledge and performance of BSE from 44.2% to 88.4% but there was no change in control group. Being in intervention group (RR=2.714, 95% CI= 1.760 - 4.186, p=0.001) and education (RR=0.573, 95% CI= 0.361 - 0.910, p=0.018) showed positive association with BSE performance. Upon adjusting with age, marital status, family history and education, intervention group (RR=2.570, 95% CI= 1.654 - 3.992, p= 0.001) remained significant while education (RR=1.466, 95% CI =0.910 - 2.363, p=0.116) became insignificant. Continuous...

scholarly journals Task dependence of odor discrimination: choosing between speed and accuracy

2018 ◽  
Vol 119 (2) ◽  
pp. 377-379 ◽  
Author(s):  
Jack Brooks ◽  
Jennifer Nicholas ◽  
Jennifer J. Robertson
Keyword(s):  
Experimental Design ◽  
Odor Discrimination ◽  
Sampling Time ◽  
Complex Task ◽  
Evidence Accumulation ◽  
Task Dependence ◽  
Study Results ◽  
Olfactory Processing ◽  
And Performance ◽  
Speed And Accuracy

Odor discrimination is a complex task that may be improved by increasing sampling time to facilitate evidence accumulation. However, experiments testing this phenomenon in olfaction have produced conflicting results. To resolve this disparity, Frederick et al. (Frederick DE, Brown A, Tacopina S, Mehta N, Vujovic M, Brim E, Amina T, Fixsen B, Kay LM. J Neurosci 37: 4416–4426, 2017) conducted experiments that suggest that sampling time and performance are task dependent. Their findings have implications for understanding olfactory processing and experimental design, specifically the effect of subtle differences in experimental design on study results.

Formation and Simulation of Cutting-Direction Burr in Orthogonal Cutting

2007 ◽  
Vol 24-25 ◽  
pp. 249-254 ◽  
Author(s):  
Hai Jun Qu ◽  
Gui Cheng Wang ◽  
Hong Jie Pei ◽  
Qin Feng Li ◽  
Yun Ming Zhu
Keyword(s):  
Shear Zone ◽  
Formation Process ◽  
Orthogonal Cutting ◽  
Shear Angle ◽  
Burr Formation ◽  
Size And Shape ◽  
Study Results ◽  
Edge Quality ◽  
And Performance ◽  
Cutting Direction

The cutting-direction burr is one of the important factors that influence the edge quality and performance of precision parts. The cutting-direction burr formation process is simulated with DeformTH3D. The mechanism of cutting-direction burr formation is analyzed in terms of the results of the simulation. The negative shear zone and initiation negative shear angle are discussed too. Study results show that the deformation of CDE is an important factor affect the cutting direction burrs’ size and shape.

scholarly journals Preference and performance of the gypsy moth cater­pillars on sweet chestnut and some oak species

2010 ◽  
pp. 113-124 ◽  
Author(s):  
Slobodan Milanovic
Keyword(s):  
Gypsy Moth ◽  
Sweet Chestnut ◽  
Sessile Oak ◽  
Preference Index ◽  
Mixed Plantations ◽  
Study Results ◽  
Turkey Oak ◽  
And Performance ◽  
Common Oak ◽  
Oak Leaves

In the establishment of mixed plantations, it is necessary to examine previously the relations of the principal and the admixed species and the most significant pests. This paper presents the results of the study of the gypsy moth caterpillar preference and performance on sweet chestnut and four oak species. Preference index is the highest for Hungarian oak (0.83) and Turkey oak (0.77), for sessile oak it is significantly lower (0.33), and for common oak it is equal to 0. In combination with sweet chestnut, the gypsy moth second-instar caterpillars prefer Hungarian oak, i.e. Turkey oak leaves. In combination with sessile oak or common oak, the gypsy moth caterpillars prefer sweet chestnut leaves. The analyzed parameters which characterise the performance of the gypsy moth fourth-instar caterpillars are lower for all study oak species compared to sweet chestnut, except in the case of Turkey oak. Based on the study results and the adopted principle that the mixture should be composed of the most favourable species, which will serve as the 'trap plant' during the gypsy moth outbreak, it can be concluded that Turkey oak is more favourable for the mixture with sweet chestnut than the other analyzed oak species.

scholarly journals Testing the Mediating Role of Career Development in Affecting Intellectual Capital and Organizational Culture on Employee Performance: Evidence of Local Banks in Yogyakarta, Indonesia

2021 ◽  
Vol 23 (1) ◽  
pp. 16-32
Author(s):  
Titi Laras ◽  
Rutha Mathilde Santana ◽  
Bambang Jatmiko ◽  
Tiyas Puji Utami
Keyword(s):  
Organizational Culture ◽  
Career Development ◽  
Intellectual Capital ◽  
Structural Equation ◽  
Employee Performance ◽  
Equation Modeling ◽  
Study Results ◽  
And Performance ◽  
Branch Office

Research aims: This study aims to examine the role of career development in mediating the relationship between intellectual capital and organizational culture on employee performance.Design/Methodology/Approach: This study used a proportional stratified random sampling method with 126 permanent employees of local banks in Yogyakarta, Indonesia, as research respondents. The respondents included Head Office, Main Branch Office, and Senopati Branch Office. The data were collected by distributing a questionnaire, and the secondary data were in the form of data or documents that supported and strengthened the primary information from books, magazines, journals, and other documents. Then, the analytical tool utilized in this study was SEM (Structural Equation Modeling) to test the research hypotheses.Research findings: The results showed that intellectual capital and organizational culture had a positive and significant effect on career development and performance, but career development had no positive and significant effect on performance. Meanwhile, career development could not mediate the effect of intellectual capital and organizational culture on performance.Theoretical contribution/Originality: The study results contribute to the literature (body of knowledge), especially as additional discussion toward theory and literature related to intellectual capital, organizational culture, career development, and performance in local banks, which is still very limited.

scholarly journals WORKING PERFORMANCE OF STUDENT SPORT CENTER MANAGEMENT IN NORTH SUMATERA (A Correlation Study between Job Satisfaction and Management Knowledge and Working Performance of Student Sport Center Management in North Sumatera)

2017 ◽  
Vol 1 (1) ◽  
pp. 6
Author(s):  
Puji Ratno ◽  
Zen Fadli
Keyword(s):  
Job Satisfaction ◽  
Key Words ◽  
Training And Development ◽  
Correlation Study ◽  
Management Team ◽  
Development Management ◽  
Management Knowledge ◽  
Working Performance ◽  
And Performance

Abstract This current study was conducted to arrive at the scientific and accurate answer to decide whether there was correlation between Job Satisfaction and Management Knowledge and Working Performance of Student Sport Center Management, either working individually or collaboratively. Management team of Training and Development in Student Sport Center North Sumatera as many as 30 people were chosen as the subjects of this current study. This study was conducted on February-March 2012. This research used correlation approach technique in taking samples by using total sampling. It was concluded that: 1) There was a significant correlation between Job Satisfaction and Working  Performance of Training and Development Management of Student Sport Center North Sumatera, which resulted t-count = 5.20 > t-table = 1.70; 2) There was a significant correlation between Management Knowledge and Working Performance of Training and Development Management of Student Sport Center North Sumatera, which resulted t-count = 3.32> t-table = 1.70; and 3) There was a significant correlation between Job Satisfaction and Management Knowledge and  Performance of Training and Development Management of Student Sport Center North Sumatera, which resulted F-count =20.37 > F-table = 3.35. Key words: job satisfaction, management knowledge, performance

scholarly journals The Impact of Coal and Biomass Co-Firing on the Economy of Power Plant Carbon Capture

2020 ◽  
Vol 12 (2) ◽  
pp. 67-77
Author(s):  
Quan Zhuang ◽  
Philip Geddis ◽  
Bruce Clements
Keyword(s):  
Economic Evaluation ◽  
Power Plant ◽  
Incremental Cost ◽  
Co2 Capture ◽  
Electricity Generation ◽  
Carbon Capture ◽  
Lower Cost ◽  
Study Results ◽  
And Performance ◽  
The Impact

A detailed economic evaluation was carried out to determine the impact of biomass and coal co-firing on power plant carbon capture by methods of plants equipment designing factors and performance, and the sum up of the associated breakdowns of CAPEX and OPEX. Based on the assumptions of the CO2 neutrality of biomass and likely governmental incentives to reduce CO2 emissions, the study results show that biomass and coal co-firing would result in both lower cost of carbon avoided (carbon capture) and lower incremental cost of electricity generation when MEA solvent carbon capture is applied. Two scenarios for co-firing with carbon capture, 30% biomass blending and 90% or 60% CO2 capture from stack, indicate different preference depending on lower or higher incentives.

Changes in Form and Style in Randai Performance at The Minangkabau Diaspora in Malaysia

2022 ◽  
Vol 21 (2) ◽  
pp. 340-355
Author(s):  
Indrayuda Indrayuda ◽  
Mohd Effindi Samsuddin
Keyword(s):  
Local Community ◽  
Field Studies ◽  
Peninsular Malaysia ◽  
Snowball Sampling ◽  
Long Distance ◽  
Taxonomic Analysis ◽  
Study Results ◽  
Observation Instruments ◽  
Cultural Themes ◽  
And Performance

This article reveals the changes in form and style of the Randai performance performed by the Minangkabau’s diaspora in Malaysia. The novelty of this research is the study of changes in forms and styles in Randai carried out by the Malaysian Minangkabau diaspora. The disconnection of socio-cultural communication and the long distance between Minangkabau and Peninsular Malaysia impacts the shift in forms and styles of Randai in the Minangkabau diaspora. This research was conducted qualitatively by designing research works such as pre-field studies, by collecting preliminary data based on a diffusion approach. In the field stage, the informants were selected by snowball sampling. The interview and observation instruments were designed based on the performance structure and performance procedures. Researchers conducted data analysis using the techniques recommended by Spradley, namely: (1) domain analysis, (2) taxonomic analysis, (3) componential analysis, and (4) discovering cultural themes. The study results revealed that the forms and styles were caused by mixing cultures between the diaspora and the Malaysian Malays. These changes were done so that the local community could accept Randai. In addition, Randai can be easily learned and cultivated by the Malay Malays and easily expressed by the Malaysian community and the Minangkabau diaspora as the perpetrators of Randai. These changes occur through a process of adaptation and acculturation. The implication of this research is the emergence of a new Randai model, namely Randai, which refers to local culture, both from the aspect of the story, Silat style, and music, as an identity and tradition for the Malaysian Minangkabau diaspora for the future.

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