Designing Compressor Installations for Reliability

2000 ◽  
Author(s):  
Shelley D. Greenfield ◽  
Brian C. Howes ◽  
Alasdair Robinson ◽  
William Eckert
Keyword(s):  
Mode Shapes ◽  
Reciprocating Compressor ◽  
Dynamic Stresses ◽  
Minimal Impact ◽  
Economical Design ◽  
Compressor Installation ◽  
The Cost ◽  
And Control ◽  
Analytical Tools ◽  
Gas Pulsations

This paper discusses and illustrates how the application of analytical tools, if properly applied, during the design process ensures a design that is both reliable and economic. Emphasis is on the dynamic behavior of centrifugal and reciprocating compressors. Illustrations deal with both types of compressors. The key requirement is that pulsations, vibration levels and dynamic stresses must be low enough, that there is minimal impact on performance or reliability, while maintaining an economical design. To achieve this result, it is necessary to understand and control forcing functions, natural frequencies, mode shapes and dynamic stiffnesses. These considerations apply to rotor dynamics, piping vibration, torsional vibration, skid and foundation vibration. In addition, similar considerations apply to gas pulsations, where the interaction of the piping geometry with pressure pulsations, (arising from the uneven flow of gas through the suction and discharge nozzles), can produce significant forces and stresses for both reciprocating and centrifugal compressors, as well as degradation of performance. Computer modeling can be used to avoid problems that reduce reliability, degrade performance and increase maintenance. Considerations for determining the appropriate level of analysis are outlined. The probability and cost of events in the absence of suitable design are discussed. The cost of these events is compared to relevant design costs. The practical implications are illustrated with three cases where adequate design modeling and optimization was not done. One case involves a lateral critical and a structural resonance in a centrifugal compressor installation. The second involves a piping failure in a reciprocating compressor installation. The third involves a torsional failure in a reciprocating compressor installation.

Efficiency Measurement in

2012 ◽  
Vol 4 (2) ◽  
pp. 1-18 ◽  
Author(s):  
Qing Cao ◽  
Karyl B. Leggio ◽  
Marc J. Schniederjans
Keyword(s):  
Market Segments ◽  
Profit Model ◽  
Rural Markets ◽  
Customer Base ◽  
Geographically Dispersed ◽  
Small Market ◽  
The Cost ◽  
And Control ◽  
Analytical Tools ◽  
Number Of Branches

Banking is a competitive market since the industry deregulated. Consumers’ demand for convenience services led to an increase in the number of branches to serve a geographically dispersed customer base. Increasing the number of branches indiscriminately is not advisable since more branches increase the cost structure for the bank. Banking executives can evaluate the relative efficiency of branches, segments, and markets using analytical tools such as DEA. This research assists the branch manager with understanding the efficiency of branches and segments using two alternative intermediation models and a profit model. The results show that large markets are more efficient than small or rural markets, and large segments are generally more efficient than small market segments. The methodology employed in this study allows branch managers to proactively work to improve efficiency and control costs by adjusting inputs within the manager’s control, whether efficiency is measured based on profit models or the intermediation models.

scholarly journals Gold–Carbon Nanocomposites for Environmental Contaminant Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 719
Author(s):  
Shahrooz Rahmati ◽  
William Doherty ◽  
Arman Amani Babadi ◽  
Muhamad Syamim Akmal Che Mansor ◽  
Nurhidayatullaili Muhd Julkapli ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
High Sensitivity ◽  
Environmental Crisis ◽  
World Population ◽  
Chemical Contaminants ◽  
Carbon Nanocomposites ◽  
Minimal Sample ◽  
Wide Range ◽  
And Control ◽  
Analytical Tools

The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold–carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.

scholarly journals Multi-Blockchain-Based IoT Data Processing Techniques to Ensure the Integrity of IoT Data in AIoT Edge Computing Environments

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3515
Author(s):  
Sung-Ho Sim ◽  
Yoon-Su Jeong
Keyword(s):  
Low Cost ◽  
Third Party ◽  
Monitoring And Control ◽  
Constant Size ◽  
Computing Environments ◽  
Iot Devices ◽  
Cloud Servers ◽  
The Cost ◽  
Processing Techniques ◽  
And Control

As the development of IoT technologies has progressed rapidly recently, most IoT data are focused on monitoring and control to process IoT data, but the cost of collecting and linking various IoT data increases, requiring the ability to proactively integrate and analyze collected IoT data so that cloud servers (data centers) can process smartly. In this paper, we propose a blockchain-based IoT big data integrity verification technique to ensure the safety of the Third Party Auditor (TPA), which has a role in auditing the integrity of AIoT data. The proposed technique aims to minimize IoT information loss by multiple blockchain groupings of information and signature keys from IoT devices. The proposed technique allows IoT information to be effectively guaranteed the integrity of AIoT data by linking hash values designated as arbitrary, constant-size blocks with previous blocks in hierarchical chains. The proposed technique performs synchronization using location information between the central server and IoT devices to manage the cost of the integrity of IoT information at low cost. In order to easily control a large number of locations of IoT devices, we perform cross-distributed and blockchain linkage processing under constant rules to improve the load and throughput generated by IoT devices.

In-line filtration reduced phlebitis associated with peripheral venous cannulation: Focus on cost-effectiveness and patients’ perspectives

2019 ◽  
Vol 21 (2) ◽  
pp. 154-160
Author(s):  
Gianluca Villa ◽  
Rosa Giua ◽  
Timothy Amass ◽  
Lorenzo Tofani ◽  
Cosimo Chelazzi ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Vascular Access ◽  
Cost Effective ◽  
Causative Factor ◽  
Control Group ◽  
Previous Trial ◽  
Venous Cannulation ◽  
Group A ◽  
The Cost ◽  
And Control

Background: In a previous trial, in-line filtration significantly prevented postoperative phlebitis associated with short peripheral venous cannulation. This study aims to describe the cost-effectiveness of in-line filtration in reducing phlebitis and examine patients’ perception of in-hospital vascular access management with and without in-line filtration. Methods: We analysed costs associated with in-line filtration: these data were prospectively recorded during the previous trial. Furthermore, we performed a follow-up for all the 268 patients enrolled in this trial. Among these, 213 patients responded and completed 6 months after hospital discharge questionnaires evaluating the perception of and satisfaction with the management of their vascular access. Results: In-line filtration group required 95.60€ more than the no-filtration group (a mean of € 0.71/patient). In terms of satisfaction with the perioperative management of their short peripheral venous cannulation, 110 (82%) and 103 (76.9%) patients, respectively, for in-line filtration and control group, completed this survey. Within in-line filtration group, 97.3% of patients were satisfied/strongly satisfied; if compared with previous experiences on short peripheral venous cannulation, 11% of them recognised in-line filtration as a relevant causative factor in determining their satisfaction. Among patients within the control group, 93.2% were satisfied/strongly satisfied, although up to 30% of them had experienced postoperative phlebitis. At the qualitative interview, they recognised no difference than previous experiences on short peripheral venous cannulation, and mentioned postoperative phlebitis as a common event that ‘normally occurs’ during a hospital stay. Conclusion: In-line filtration is cost-effective in preventing postoperative phlebitis, and it seems to contribute to increasing patient satisfaction and reducing short peripheral venous cannulation–related discomfort

Synergetic Concept of Software Control of Machining Processes on Metal-Cutting Machines

2021 ◽  
pp. 24-36
Author(s):  
V.L. Zakovorotny ◽  
V.E. Gvindzhiliya
Keyword(s):  
Tool Wear ◽  
Metal Cutting ◽  
Wear Testing ◽  
External Control ◽  
Machining Processes ◽  
Cutting Zone ◽  
Output Characteristics ◽  
The Cost ◽  
And Control ◽  
Cutting System

High precision metal-cutting machines ensure that the programmed machine actuator trajectories correspond to the real ones. For lathes these are the trajectories of the longitudinal and transverse calipers of the system, as well as the spindle. The purpose of processing is to produce parts of a given quality while minimizing the manufacturing costs. The condition of the dynamic cutting system, determined by the trajectories of forces and deformations, affects the quality indicators of parts and the cutting efficiency, which depends on the intensity of tool wear. The properties of the system change depending on the phase trajectory of the power of irreversible transformations of the energy supplied to the cutting zone by the work performed. Their changes related with the evolution of the parameters of the dynamic link formed by cutting are manifested in the development of tool wear and changes in the quality of the part. Thus, the power of irreversible energy transformations is one of the internal factors causing changes in the output characteristics of processing and the state of the process. In this regard, when processing on machine tools, there is a problem of synergistic coordination of external control (for example, the CNC program) with internal one, the source of which is the irreversible transformation of the energy supplied to the cutting zone. The article considers the problem of synergetic coordination of external and internal controls during cutting process, the solution of which will allow increasing the efficiency of processing on CNC machines. A mathematical model of a controlled dynamic cutting system and control algorithms are proposed to improve the efficiency of processing parts of a given quality while minimizing the intensity of tool wear. Testing of the developed algorithms has shown that their use reduces the cost of manufacturing parts by 1.2.

FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix

2021 ◽  
pp. 2150128
Author(s):  
Wen-Yu He ◽  
Wei-Xin Ren ◽  
Lei Cao ◽  
Quan Wang
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Damage Index ◽  
Element Model ◽  
Mode Shapes ◽  
Beam Structures ◽  
Flexibility Matrix ◽  
Damage Quantification ◽  
Modal Flexibility ◽  
The Cost

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

Cost-Effectiveness of Paving Fabrics Used to Control Reflective Cracking

2000 ◽  
Vol 1730 (1) ◽  
pp. 139-149 ◽  
Author(s):  
William G. Buttlar ◽  
Diyar Bozkurt ◽  
Barry J. Dempsey
Keyword(s):  
Life Cycle ◽  
Cost Effectiveness ◽  
Department Of Transportation ◽  
Reflective Cracking ◽  
Crack Control ◽  
Condition Rating ◽  
System A ◽  
Rigid Pavements ◽  
The Cost ◽  
And Control

The Illinois Department of Transportation (IDOT) spends $2 million annually on reflective crack control treatments; however, the cost-effectiveness of these treatments had not been reliably determined. A recent study evaluated the cost-effectiveness of IDOT reflective crack control System A, which consists of a nonwoven polypropylene paving fabric, placed either in strips longitudinally over lane-widening joints or over the entire pavement (area treatment). The study was limited to projects constructed originally as rigid pavements and subsequently rehabilitated with one or more bituminous overlays. Performance of 52 projects across Illinois was assessed through crack mapping and from distress and serviceability data in IDOT’s condition rating survey database. Comparisons of measured reflective cracking in treated and control sections revealed that System A retarded longitudinal reflective widening crack development, but it did not significantly retard transverse reflective cracking, which agrees with earlier studies. However, both strip and area applications of these fabric treatments appeared to improve overall pavement serviceability, and they were estimated to increase rehabilitation life spans by 1.1 and 3.6 years, respectively. Reduction in life-cycle costs was estimated to be 4.4 and 6.2 percent when placed in medium and large quantities, respectively, and to be at a break-even level for small quantities. However, life-cycle benefits were found to be statistically insignificant. Limited permeability testing of field cores taken on severely distressed transverse joints suggested that waterproofing benefits could exist even after crack reflection. This was consistent with the observation that, although serviceability was generally improved with area treatment, crack reflection was not retarded relative to untreated areas.

scholarly journals Cost-effectiveness of two long-lasting insecticidal nets delivery models in mass campaign in rural Mozambique

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Jorge A. H. Arroz ◽  
Baltazar Candrinho ◽  
Chandana Mendis ◽  
Melanie Lopez ◽  
Maria do Rosário O. Martins
Keyword(s):  
Cost Effectiveness ◽  
Cost Effective ◽  
Universal Coverage ◽  
Cost Effectiveness Ratio ◽  
Net Benefit ◽  
Incremental Net Benefit ◽  
The Cost ◽  
And Control ◽  
Delivery Models ◽  
Long Lasting Insecticidal Nets

Abstract Objective The aim is to compare the cost-effectiveness of two long-lasting insecticidal nets (LLINs) delivery models (standard vs. new) in universal coverage (UC) campaigns in rural Mozambique. Results The total financial cost of delivering LLINs was US$ 231,237.30 and US$ 174,790.14 in the intervention (302,648 LLINs were delivered) and control districts (219,613 LLINs were delivered), respectively. The average cost-effectiveness ratio (ACER) per LLIN delivered and ACER per household (HH) achieving UC was lower in the intervention districts. The incremental cost-effectiveness ratio (ICER) per LLIN and ICER per HH reaching UC were US$ 0.68 and US$ 2.24, respectively. Both incremental net benefit (for delivered LLIN and for HHs reaching UC) were positive (intervention deemed cost-effective). Overall, the newer delivery model was the more cost-effective intervention. However, the long-term sustainability of either delivery models is far from guaranteed in Mozambique’s current economic context.

scholarly journals PENGGUNAAN STANDARD WBS (WORK BREAKDOWN STRUCTURE) PADA PROYEK BANGUNAN GEDUNG

2019 ◽  
Vol 5 (1) ◽  
pp. 29-34
Author(s):  
Ayu Herzanita
Keyword(s):  
Current Problem ◽  
Construction Project ◽  
Project Performance ◽  
Work Package ◽  
Building Projects ◽  
Work Breakdown Structure ◽  
Time Performance ◽  
The Cost ◽  
And Control ◽  
Method Approach

WBS (Work Breakdown Structure) plays an important role in every construction project. WBS is a hierarchy of decreasing scope of work to become the smallest level called a work package, making it easier in the process of project management and control. The current problem is that many contractors in Indonesia, both large and small contractors, do not understand the importance of using WBS in a construction project. This causes project performance to be less than optimal, especially on cost and time performance. Currently, WBS standards have been developed for building projects. In this study will look at the cost and time performance of the project from the use of WBS standard building. The sample used in this study are projects that have applied the use of project standards. The projects include Building X, Lecture Building Y, and Sports Facility Building Z. The method used in this study is the EVM (Earn Value Method) approach, collecting data using questionnaires. The results showed that using the WBS standard had an effect on cost and time performance. Good cost and time performance is shown in the Building X and Lecture Y buildings. While the cost and time performance of the Z Sports Facility Building tends to be unstable. This is because the work items that exist in the WBS standard are not in accordance with the project conditions, so it is necessary to adjust work items.

scholarly journals Corrigendum: Brief alcohol intervention for risky drinking in young people aged 14–15 years in secondary schools: the SIPS JR-HIGH RCT

2020 ◽  
Vol 7 (9) ◽  
pp. 135-142
Author(s):  
Emma L Giles ◽  
Grant J McGeechan ◽  
Simon Coulton ◽  
Paolo Deluca ◽  
Colin Drummond ◽  
...  
Keyword(s):  
Young People ◽  
Cost Utility ◽  
Sensitivity Analyses ◽  
Alcohol Intervention ◽  
Risky Drinking ◽  
Brief Alcohol Intervention ◽  
Utility Evaluation ◽  
The Cost ◽  
Phd Thesis ◽  
And Control

Abstract During independent re-analysis of the cost data for a PhD thesis, a coding error was identified in one of the sensitivity analyses of the cost-utility evaluation of the trial looking at the effect of excluding from the intervention and control costs the cost of missed school days.

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