scholarly journals Shock Analysis Method for Systematic Performance Evaluation of Component Embedded in Handheld Electronic Devices

2006 ◽  
Vol 13 (6) ◽  
pp. 607-618 ◽  
Author(s):  
C.S. Chin
Keyword(s):  
Performance Evaluation ◽  
Test Procedure ◽  
Drop Test ◽  
Velocity Change ◽  
Small Component ◽  
Shock Test ◽  
Shock Testing ◽  
Mp3 Player ◽  
Free Drop ◽  
The Impact

It is important to identify the robustness of product (or embedded component inside the product) against shock due to free drop. With the increasing mobile and fast-paced lifestyle of the average consumer, much is required of the products; such as consumers expect mobile products to continue to operate after drop impact. Since free drop test is commonly used to evaluate the robustness of small component embedded in MP3 player, it is difficult to produce a repeatable shock reading due to highly uncontrolled orientation during the impact on ground. Hence attention has been focus on shock table testing, which produces a higher repeatable result. But it failed to demonstrate the actual shock with the presence of rotational movement due to free drop and also it suffers from a similar limitation of repeatability. From drop to drop, shock tables can vary about ± 5% in velocity change but suitable for making a consistent tracking the product improvement.Although many test procedure (such as ASTM D3332 [5]) have been written around shock test machines, as a whole, the test perform on the shock tables have no direct correlation over the free-drop testing. Since both will have some velocity change variability. Some products react more to torsion forces than they do to orthogonal forces, fortunately, due to the size of the product, the exposure to this torsion force is less prominent. Since the intent of lab testing is to re-create real world events, a unique ways to establish a shock test that encompasses the features of the two tests are needed. Thus, establishing the robustness of the small component against shock due to topple drop at various tilt angle under different drop orientations and platform (such as on the office table), on a MP3 player is needed. This eventually enables a high repeatable and realistic shock testing for product performance evaluation in MP3 player.There are few advantages of using tilt tester for shock testing. Firstly, close approximations to the actual free drops test with better repeatability. Secondly, it ensures that the shock level is reduced prior to performing a final free drop test (using actual product) and hence reduces the cost. Thirdly, it reduces the number of trials and cycle time needed for shock testing. Lastly, it provides a platform for shock absorber design for component (embedded in the MP3 player) as shown in the Section 3.

Comprehensive Income: which potential effects on firms' performance evaluation and users' decision process?

2016 ◽  
pp. 55-94
Author(s):  
Pier Luigi Marchini ◽  
Carlotta D'Este
Keyword(s):  
Performance Evaluation ◽  
Decision Process ◽  
Financial Analysts ◽  
Listed Companies ◽  
Financial Statement ◽  
Comprehensive Income ◽  
Other Comprehensive Income ◽  
Gains And Losses ◽  
The Impact

The reporting of comprehensive income is becoming increasingly important. After the introduction of Other Comprehensive Income (OCI) reporting, as required by the 2007 IAS 1-revised, the IASB is currently seeking inputs from investors on the usefulness of unrealized gains and losses and on the role of comprehensive income. This circumstance is of particular relevance in code law countries, as local pre-IFRS accounting models influence financial statement preparers and users. This study aims at investigating the role played by unrealized gains and losses reporting on users' decision process, by examining the impact of OCI on the Italian listed companies RoE ratio and by surveying a sample of financial analysts, also content analysing their formal reports. The results show that the reporting of comprehensive income does not affect the financial statement users' decision process, although it statistically affects Italian listed entities' performance.

scholarly journals Power Hardware-in-the-Loop-Based Performance Analysis of Different Converter Controllers for Fast Active Power Regulation in Low-Inertia Power Systems

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3274
Author(s):  
Jose Rueda Torres ◽  
Zameer Ahmad ◽  
Nidarshan Veera Kumar ◽  
Elyas Rakhshani ◽  
Ebrahim Adabi ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Power Systems ◽  
Real Time ◽  
Control Strategies ◽  
Active Power ◽  
Power Electronic ◽  
Hardware In The Loop ◽  
Digital Controllers ◽  
Power Regulation ◽  
The Impact

Future electrical power systems will be dominated by power electronic converters, which are deployed for the integration of renewable power plants, responsive demand, and different types of storage systems. The stability of such systems will strongly depend on the control strategies attached to the converters. In this context, laboratory-scale setups are becoming the key tools for prototyping and evaluating the performance and robustness of different converter technologies and control strategies. The performance evaluation of control strategies for dynamic frequency support using fast active power regulation (FAPR) requires the urgent development of a suitable power hardware-in-the-loop (PHIL) setup. In this paper, the most prominent emerging types of FAPR are selected and studied: droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. A novel setup for PHIL-based performance evaluation of these strategies is proposed. The setup combines the advanced modeling and simulation functions of a real-time digital simulation platform (RTDS), an external programmable unit to implement the studied FAPR control strategies as digital controllers, and actual hardware. The hardware setup consists of a grid emulator to recreate the dynamic response as seen from the interface bus of the grid side converter of a power electronic-interfaced device (e.g., type-IV wind turbines), and a mockup voltage source converter (VSC, i.e., a device under test (DUT)). The DUT is virtually interfaced to one high-voltage bus of the electromagnetic transient (EMT) representation of a variant of the IEEE 9 bus test system, which has been modified to consider an operating condition with 52% of the total supply provided by wind power generation. The selected and programmed FAPR strategies are applied to the DUT, with the ultimate goal of ascertaining its feasibility and effectiveness with respect to the pure software-based EMT representation performed in real time. Particularly, the time-varying response of the active power injection by each FAPR control strategy and the impact on the instantaneous frequency excursions occurring in the frequency containment periods are analyzed. The performed tests show the degree of improvements on both the rate-of-change-of-frequency (RoCoF) and the maximum frequency excursion (e.g., nadir).

scholarly journals Sensitivity of Ultrasonic Coda Wave Interferometry to Material Damage—Observations from a Virtual Concrete Lab

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4033
Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  
Keyword(s):  
Elastic Moduli ◽  
Concrete Specimen ◽  
Coda Wave ◽  
Velocity Change ◽  
Damage Scenarios ◽  
Different Types ◽  
Source Signal ◽  
The Impact ◽  
Structural Scale ◽  
Coda Wave Interferometry

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.

Human Performance Evaluation of a Metaphor Graphic Display for Respiratory Data

1994 ◽  
Vol 33 (04) ◽  
pp. 390-396 ◽  
Author(s):  
J. G. Stewart ◽  
W. G. Cole
Keyword(s):  
Performance Evaluation ◽  
Human Performance ◽  
Pattern Detection ◽  
Data Sets ◽  
Complex Task ◽  
Graphic Display ◽  
Literal Sense ◽  
Single Number ◽  
The Impact ◽  
Human Problem

Abstract:Metaphor graphics are data displays designed to look like corresponding variables in the real world, but in a non-literal sense of “look like”. Evaluation of the impact of these graphics on human problem solving has twice been carried out, but with conflicting results. The present experiment attempted to clarify the discrepancies between these findings by using a complex task in which expert subjects interpreted respiratory data. The metaphor graphic display led to interpretations twice as fast as a tabular (flowsheet) format, suggesting that conflict between earlier studies is due either to differences in training or to differences in goodness of metaphor, Findings to date indicate that metaphor graphics work with complex as well as simple data sets, pattern detection as well as single number reporting tasks, and with expert as well as novice subjects.

Numerical Simulation and Experimental Measurement of a Printed Circuit Board Subjected to Drop Test

2009 ◽  
Vol 419-420 ◽  
pp. 37-40
Author(s):  
Shiuh Chuan Her ◽  
Shien Chin Lan ◽  
Chun Yen Liu ◽  
Bo Ren Yao
Keyword(s):  
Finite Element ◽  
Experimental Measurement ◽  
Test Specimen ◽  
Printed Circuit Board ◽  
Drop Impact ◽  
Simulation Technique ◽  
Drop Test ◽  
Circuit Board ◽  
Printed Circuit ◽  
The Impact

Drop test is one of the common methods for determining the reliability of electronic products under actual transportation conditions. The aim of this study is to develop a reliable drop impact simulation technique. The test specimen of a printed circuit board is clamped at two edges on a test fixture and mounted on the drop test machine platform. The drop table is raised at the height of 50mm and dropped with free fall to impinge four half-spheres of Teflon. One accelerometer is mounted on the center of the specimen to measure the impact pulse. The commercial finite element software ANSYS/LS-DYNA is applied to compute the impact acceleration and dynamic strain on the test specimen during the drop impact. The finite element results are compared to the experimental measurement of acceleration with good correlation between simulation and drop testing. With the accurate simulation technique, one is capable of predicting the impact response and characterizing the failure mode prior to real reliability test.

A novel retractable landing gear of a light amphibious airplane design, synthesis, analysis, and implementation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sinchai Chinvorarat ◽  
Pumyos Vallikul
Keyword(s):  
Impact Load ◽  
Landing Gear ◽  
Drop Test ◽  
Drop Height ◽  
Core Element ◽  
Design Synthesis ◽  
Content Type ◽  
And Performance ◽  
Correct Path ◽  
The Impact

Purpose The purpose of this paper is to present a novel retractable main landing gear for a light amphibious airplane, while the design, synthesis and analysis are given in details for constructing the main landing gear. Design/methodology/approach The constraint three-position synthesis has given the correct path of all linkages that suitably fit the landing gear into the compartment. The additional lock-link is introduced into the design to ensure the securement of the mechanism while landing. Having the telescopic gas-oil shock strut as a core element to absorb the impact load, it enhances the ability and efficiency to withstand higher impact than others type of light amphibious airplane. Findings By kinematics bifurcation analysis, the optimized value of the unlock spring stiffness at 90 N/m can be found to tremendously reduce the extended-retracted linear actuator force from 500 N to 150 N at the beginning of the retraction sequence. This could limit the size and weight of the landing gear actuator of the light amphibious airplane. Practical implications The drop test of the landing gear to comply with the ASTM f-2245 (Standard Specification for Design and Performance of a Light Sport Airplane) reveals that the novel landing gear can withstand the impact load at the drop height determined by the standard. The maximum impact loading 4.8 G occurs at the drop height of 300 mm, and there is no sign of any detrimental or failure of the landing gear or the structure of the light amphibious airplane. The impact settling time response reaches the 2% of steady-state value in approximately 1.2 s that ensure the safety and stability of the amphibious airplane if it subjects to an accidentally hard landing. Originality/value This paper presents unique applications of a retractable main landing gear of a light amphibious airplane. The proposed landing gear functions properly and complies with the drop test standard, ensuring the safety and reliability of the airplane and exploiting the airworthiness certification process.

Suggestions to the test procedure for technical means of protection of steel welded domestic LPG gas cylinders from physical destruction in fire

2021 ◽  
pp. 67-72
Author(s):  
Владимир Леонидович Малкин ◽  
Владимир Александрович Угорелов ◽  
Петр Алексеевич Леончук ◽  
Руслан Андреевич Загуменников
Keyword(s):  
Coming Out ◽  
Test Procedure ◽  
Video Recording ◽  
Heating System ◽  
Measuring System ◽  
Cylinder Surface ◽  
In Fire ◽  
Gas Leaks ◽  
The Impact ◽  
Gas Cylinders

Разработана методика проведения испытаний технических средств защиты стальных сварных бытовых баллонов для сжиженных углеводородных газов (СУГ) от физического разрушения при воздействии на них пожара. В методике содержатся требования к отбору газовых баллонов, рассматриваемым модельным сценариям, установке для испытаний, мероприятиям по подготовке испытаний, порядку их проведения, к отчету о проведении испытаний. Использование предлагаемой методики позволит с высокой степенью достоверности оценивать эффективность применения технических средств защиты стальных бытовых баллонов для СУГ от физического разрушения при воздействии пожара. The paper contains proposals for inclusion in the testing methodology for technical means of protecting gas cylinders from physical destruction. The proposals relate to the choice of typical scenarios characteristic for emergencies and fire development in a room with LPG cylinders: the ingress of cylinders into the fire center, the impact on the cylinder surface of the heat flow of the adjacent fire center; the impact on the surface of the cylinder of LPG vapors jet combustion, simulating the effect of combustion of LPG vapors coming out of the outlet of the valve (safety valve or membrane) of the adjacent cylinder. The design of the installation for testing cylinders in accordance with the above scenarios is presented. There are given requirements for the test preparation procedure, including the verification of documentation, installation of technical protective equipment, filling and delivery of cylinders, checking for gas leaks from cylinders after delivery, installation for testing. A detailed description of the installation procedure is given in accordance with the presented diagrams for various test scenarios. The basic diagrams of the measuring system for the pressure inside the cylinder, mounting of thermocouples on the wall of the cylinder, and remote supply of liquid fuel to trays are described. There is described the test procedure, which consists of turning on the recording systems, gas supplying to the installation, activating the cylinder heating system, video recording of the experiment with timing, closing the valve in front of the pressure sensor after the end of combustion, discharging LPG from the sealed cylinder to the burner. The requirements for the composition of the test report are given, which make it possible to confirm the reliability of the experiments.

scholarly journals Opinions of school principals and teachers about teacher evaluation according to performance criteriaPerformans kriterlerine göre öğretmenlerin değerlendirilmesine ilişkin okul müdürü ve öğretmen görüşleri

2017 ◽  
Vol 14 (2) ◽  
pp. 1647 ◽  
Author(s):  
Ferudun Sezgin ◽  
Ayşe Tınmaz ◽  
Sezgin Tetik
Keyword(s):  
Professional Development ◽  
Performance Evaluation ◽  
Phenomenological Study ◽  
School Principals ◽  
Evaluation Process ◽  
Structured Interview ◽  
Performance Criteria ◽  
Ministry Of Education ◽  
Study Participants ◽  
The Impact

The purpose of this study was to examine the opinions of school principals and teachers about the new implication process which teachers are being evaluated by school principals according to performance criteria. Phenomenological study design was chosen in this qualitative research. Participants were selected according to maximum variation sampling which is one of the purposeful sampling methods. Data were collected from 11 school principals and 14 teachers via semi-structured interview forms in Tokat city center. Data were analyzed according to descriptive analyzing technique. According to the results obtained in the study, participants stated that the purpose of current performance evaluation is the evaluation of teachers and to support their professional development. About the new application’s access to the purposes, while many of the teachers reported that the system could not achieve its goals, most of the school principals stated that the system would reach the goals with some shortcomings. Participants criticized the system for fast coming up and implementation. Participants stated that school principals were not qualified for this system. The most important strength of the system was defined as the teacher’s close awareness of the school principals. According to teachers’ views about the weaknesses of the system; the impact of conflicts or prejudices affecting school, school principals’ failure to take into account the criteria list, the existence of biased behaviors, the fact that principals were not educated in supervision, erroneous or incomplete practices in branch-specific evaluations, the deterioration of organizational peace. The majority of school principals reported that the applied system could contribute to the professional development of teachers, while the majority of teachers thought that the system would make a limited contribution. A two-day seminar was held with the school principals while training for teachers was not arranged by the Ministry of Education prior to the performance evaluation process. In the study, some suggestions were also made regarding the development of the current practice and the assessment of teacher performance in Turkey.Extended English abstract is in the end of PDF (TURKISH) file. ÖzetBu çalışmanın amacı öğretmenlerin performans kriterlerine göre okul müdürleri tarafından değerlendirildiği yeni uygulama konusunda okul müdürleri ve öğretmenlerin görüşlerini ortaya koymaktır. Nitel araştırma yöntemine göre tasarlanan bu çalışmada olgu bilim deseni benimsenmiştir. Çalışmada katılımcılar amaçlı örnekleme yöntemlerinden maksimum çeşitlemeye göre oluşturulmuştur. Tokat il merkezinde görev yapmakta olan 11 okul müdürü ve 14 öğretmenle yarı yapılandırılmış görüşme formu kullanılarak veri toplanmıştır. Veriler betimsel analiz tekniğine göre çözümlenmiştir. Araştırmada elde edilen verilere göre katılımcılar mevcut performans değerlendirme uygulamasının amacının daha çok öğretmenlerin değerlendirilmesi ve mesleki gelişimlerini artırma olduğu yönünde görüş belirtmişlerdir. Yeni uygulamanın amacına ulaşabilmesine ilişkin öğretmenlerin çoğunluğu sistemin amacını gerçekleştiremeyeceğini düşünürken okul müdürlerinin çoğunluğu bazı eksiklikler belirtmekle birlikte sistemin amacına ulaşabileceğini ifade etmektedirler. Uygulanma süreciyle ilgili katılımcılar sistemin bir anda gündeme gelmesi ve uygulanmasını eleştirmektedir. Katılımcılar okul müdürlerinin bu konuda yeterli olmadığını düşünmektedir. Sisteminin en önemli güçlü yanının okul müdürünün öğretmeni yakından tanıması olduğu ifade edilmiştir. Sistemin zayıf yönleri ile ilgili olarak öğretmenler; okulda yaşanacak çatışmaların veya önyargıların değerlendirmeyi etkilemesi, okul müdürlerinin kriter listesini dikkate almaması, taraflı davranışların varlığı, müdürlerin denetim konusunda eğitimli olmamaları, branşa özgü değerlendirmelerde hatalı veya eksik uygulama, örgüt barışının bozulması şeklinde görüş belirtmişlerdir. Okul müdürlerinin çoğunluğu uygulanmakta olan sistemin öğretmenlerin mesleki gelişimine katkı sağlayacağını belirtirken öğretmenlerin çoğunluğu kısıtlı katkı sağlayacağını düşünmektedir. Performans değerlendirme süreci öncesinde Milli Eğitim Bakanlığı tarafından öğretmenlere yönelik bir eğitim düzenlenmezken, okul müdürlerine iki günlük bir seminer düzenlenmiştir. Çalışmada ayrıca mevcut uygulamanın geliştirilmesi ile ilgili ve Türkiye’de genel anlamda öğretmen performansının değerlendirilmesi ile ilgili olarak birtakım önerilerde bulunulmuştur.

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