Selection of High Performance Low Flow Compressors

Author(s):  
S. Sayyed

With rapidly escallating energy costs, the need to use energy as efficiently and economically as possible has led to new development programs particularly in the low flow areas. New techniques in the design of impellers as well as stationary flow passages have been developed to produce highly efficient compression stages, and at the same time calculation methods to accurately predict the aerodynamic performance for low flow applications are being continually upgraded to provide a reliable and efficient machine to be employed in the emerging applications. This paper provides some of the insights, which need to be considered when selecting low flow high performance centrifugal compressors.

Author(s):  
Hang Ren ◽  
Junmo Zhang ◽  
Yanhong Tong ◽  
Mingxin Zhang ◽  
Xiaoli Zhao ◽  
...  

2021 ◽  
Vol 13 (4) ◽  
pp. 2150
Author(s):  
Carmen Emilia Chașovschi ◽  
Carmen Nastase ◽  
Mihai Popescu ◽  
Adrian-Liviu Scutariu ◽  
Iulian-Alexandru Condratov

The research aim was to identify the training needs of entrepreneurs and employees within small and medium enterprises (SMEs) from the Suceava, Chernivtsi, and Bălți regions, to analyze the specific training practices in the cross-border area, and to identify the common features or the disparities. The research contains an exploratory survey, based on a semi-structured questionnaire that investigates the training needs in the SMEs and specific training practices with a comparative approach. The results relate to the challenges faced by transformation economies and by the specificities of SMEs from these remote areas. Additionally, the research connects the factors involved in planning and delivering training programs for employees in SMEs in this EU peripheral area with the weaknesses of the companies in facing the market competitive economy. The results of the survey disclosed some common features and specificities related to training needs, training responsibilities, and interests in the SMEs from this cross-border area. The discussions are relevant for different categories of stakeholders, at the micro-level, for the management of the companies, but also on a larger scale, in planning the new development programs for the labor market in the targeted areas.


Solar RRL ◽  
2021 ◽  
pp. 2100450
Author(s):  
Bing-Huang Jiang ◽  
Yi-Peng Wang ◽  
Yu-Wei Su ◽  
Jia-Fu Chang ◽  
Chu-Chen Chueh ◽  
...  

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Nur Izzah Nabilah Haris ◽  
Shafreeza Sobri ◽  
Yus Aniza Yusof ◽  
Nur Kartinee Kassim

Molecular dynamics (MD) simulation is a powerful tool to study the molecular level working mechanism of corrosion inhibitors in mitigating corrosion. In the past decades, MD simulation has emerged as an instrument to investigate the interactions at the interface between the inhibitor molecule and the metal surface. Combined with experimental measurement, theoretical examination from MD simulation delivers useful information on the adsorption ability and orientation of the molecule on the surface. It relates the microscopic characteristics to the macroscopic properties which enables researchers to develop high performance inhibitors. Although there has been vast growth in the number of studies that use molecular dynamic evaluation, there is still lack of comprehensive review specifically for corrosion inhibition of organic inhibitors on ferrous metal in acidic solution. Much uncertainty still exists on the approaches and steps in performing MD simulation for corrosion system. This paper reviews the basic principle of MD simulation along with methods, selection of parameters, expected result such as adsorption energy, binding energy and inhibitor orientation, and recent publications in corrosion inhibition studies.


2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Youlong Chen ◽  
Yong Zhu ◽  
Xi Chen ◽  
Yilun Liu

In this work, the compressive buckling of a nanowire partially bonded to an elastomeric substrate is studied via finite-element method (FEM) simulations and experiments. The buckling profile of the nanowire can be divided into three regimes, i.e., the in-plane buckling, the disordered buckling in the out-of-plane direction, and the helical buckling, depending on the constraint density between the nanowire and the substrate. The selection of the buckling mode depends on the ratio d/h, where d is the distance between adjacent constraint points and h is the helical buckling spacing of a perfectly bonded nanowire. For d/h > 0.5, buckling is in-plane with wavelength λ = 2d. For 0.27 < d/h < 0.5, buckling is disordered with irregular out-of-plane displacement. While, for d/h < 0.27, buckling is helical and the buckling spacing gradually approaches to the theoretical value of a perfectly bonded nanowire. Generally, the in-plane buckling induces smaller strain in the nanowire, but consumes the largest space. Whereas the helical mode induces moderate strain in the nanowire, but takes the smallest space. The study may shed useful insights on the design and optimization of high-performance stretchable electronics and three-dimensional complex nanostructures.


Author(s):  
Andre D. L. Batako ◽  
Valery V. Kuzin ◽  
Brian Rowe

High Efficiency Deep Grinding (HEDG) has been known to secure high removal rates in grinding processes at high wheel speed, relatively large depth of cut and moderately high work speed. High removal rates in HEDG are associated with very efficient grinding and secure very low specific energy comparable to conventional cutting processes. Though there exist HEDG-enabled machine tools, the wide spread of HEDG has been very limited due to the requirement for the machine tool and process design to ensure workpiece surface integrity. HEDG is an aggressive machining process that requires an adequate selection of grinding parameters in order to be successful within a given machine tool and workpiece configuration. This paper presents progress made in the development of a specialised HEDG machine. Results of HEDG processes obtained from the designed machine tool are presented to illustrate achievable high specific removal rates. Specific grinding energies are shown alongside with measured contact arc temperatures. An enhanced single-pole thermocouple technique was used to measure the actual contact temperatures in deep cutting. The performance of conventional wheels is depicted together with the performance of a CBN wheel obtained from actual industrial tests.


2014 ◽  
Vol 608-609 ◽  
pp. 336-342
Author(s):  
Huan Liu

How to coordinate heterogeneous database to realize sharing and consistency of information not only is an important research subject in the database filed, but also is an emerging research hot spot in the field of database system. As a new development direction of computer software, it applies some new techniques to integrate the existing systems to develop new applications. The paper analyzes CSCW, XML, JDBC and heterogeneous database, and proposes a solution of heterogeneous database. The solution absorbs the thoughts of database meta data, middle ware and LDAP directory service.


1982 ◽  
Vol 15 (12) ◽  
pp. 458-463 ◽  
Author(s):  
R. S. Medlock

Flow measurement has a long history extending over a period of about 3000 years, but it was only just over 200 years ago that the subject was first studied on a scientific basis and it was only 20 years ago that a surge of new techniques became available. Today there is a wide selection of methods and equipment to enable flow to be measured whether the medium is in the form of a liquid, gas, vapour or solid, or any combination thereof. According to the application, volumetric flow rate can be measured over a range exceeding 10−5m3/h to 106m3/h which in everday terms is equivalent to a cupful per day to the flow of a very large river. The price of a flowmeter can be as small as a few pounds or in excess of £1 million depending on the accuracy and capacity required. References are made to about 50 types of flow metering devices which can be classified into 11 groups.


2015 ◽  
Vol 21 (6) ◽  
pp. 630-648 ◽  
Author(s):  
Sunil Kumar Tiwari ◽  
Sarang Pande ◽  
Sanat Agrawal ◽  
Santosh M. Bobade

Purpose – The purpose of this paper is to propose and evaluate the selection of materials for the selective laser sintering (SLS) process, which is used for low-volume production in the engineering (e.g. light weight machines, architectural modelling, high performance application, manufacturing of fuel cell, etc.), medical and many others (e.g. art and hobbies, etc.) with a keen focus on meeting customer requirements. Design/methodology/approach – The work starts with understanding the optimal process parameters, an appropriate consolidation mechanism to control microstructure, and selection of appropriate materials satisfying the property requirement for specific application area that leads to optimization of materials. Findings – Fabricating the parts using optimal process parameters, appropriate consolidation mechanism and selecting the appropriate material considering the property requirement of applications can improve part characteristics, increase acceptability, sustainability, life cycle and reliability of the SLS-fabricated parts. Originality/value – The newly proposed material selection system based on properties requirement of applications has been proven, especially in cases where non-experts or student need to select SLS process materials according to the property requirement of applications. The selection of materials based on property requirement of application may be used by practitioners from not only the engineering field, medical field and many others like art and hobbies but also academics who wish to select materials of SLS process for different applications.


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