A review of the application of acoustic emission technique in engineering

The use of acoustic emission (AE) technique for detecting and monitoring damages and the progress on damages in different structures is widely used and has earned a reputation as one of the most reliable and well-established technique in non-destructive testing (NDT). Acoustic Emission is a very efficient and effective technology used for fracture behavior and fatigue detection in metals, fiberglass, wood, composites, ceramics, concrete and plastics. It can also be used for detecting faults and pressure leaks in vessels, tanks, pipes, as well as for monitoring the progression of corrosion in welding. This paper reviews major research developments over the past few years in application of acoustic emission in numerous engineering fields, including manufacturing, civil, aerospace and material engineering

Keterkaitan Kuantitas Pekerjaan Dengan Durasi Dan Tenaga Kerja Pada Proyek Konstruksi Bangunan Bertingkat Tinggi

Dalam proyek konstruksi dibutuhkan adanya perencanaan yang baik dalam bentuk schedule yang teratur. Schedule pada proyek konstruksi berbicara mengenai durasi tiap-tiap pekerjaan pada proyek konstruksi yang dipengaruhi oleh kuantitas pekerjaan dan jumlah tenaga kerja. Kuantitas pekerjaan dapat diperoleh dari Rencana Anggaran Biaya pada proyek konstruksi. Melalui kuantitas pekerjaan yang didapat dari RAB dan durasi pekerjaan yang didapat dari schedule dapat diperoleh keterkaitan yang disebut dengan daily output. Melalui daily output dapat diperoleh berapa jumlah tenaga kerja teoritis yang dibutuhkan berdasarkan indeks SNI 2008. Fokus pekerjaan daripada penelitian ini adalah pekerjaan struktur yang meliputi pekerjaan pengecoran, pemasangan bekisting, dan pembesian pada struktur kolom, balok, plat, dan dinding. Berdasarkan perbandingan data rencana antara proyek Hotel Cleo, proyek UK Petra Gedung P1-P2, dan juga proyek Fave Hotel, maka dapat disimpulkan bahwa proyek UK. Petra Gedung P1-P2 memiliki nilai daily output dan jumlah tenaga kerja terbanyak untuk pekerjaan bekisting, pembesian, dan pengecoran pada masing-masing elemen struktur jika dibandingkan dengan proyek lainnya. Berdasarkan persentase perbedaan antara data rencana dan data nyata diatas dari daily output pada pekerjaan bekisting, pembesian dan pengecoran pada masing-masing elemen struktur bagian nyata memiliki indeks tenaga kerja yang relatif lebih sedikit jika dibandingkan dengan data rencana berdasarkan SNI 2008, kecuali pada pekerjaan pembesian tangga yang membutuhkan tenaga kerja yang lebih banyak

Cab transfer process improvement at an automotive manufacturing facility

This project is related to the improvement of cab transfer process from Painted Body Storage (PBS) area to General Assembly (GA) line. The objectives of this project are to eliminate the root cause of cab defect and to streamline the transfer process with the reduction of process cycle time. From the current process study, it is found that the lifting method causes the quality defect to the cab and the usage of different type of trolley between PBS and GA contribute to the high cycle time. The new process design has been introduced from the findings with the use of towing method and the use of common trolley for both PBS area and GA line. With the new and improved cab transfer process, the cab changing process can be eliminated. Hence, the number of operator required has been reduced, from two operators to only one operator. A trial run has been conducted with a prototype trolley and a forklift. The objectives of this project are fulfilled with the new towing method that eliminate the quality defect and the use of common trolley for both PBS and GA line resulting new cycle time of 7.13 minutes per unit from 9.77 minutes per unit. Further studies are needed for commissioning and monitoring to the new cab transfer process with the actual trolley and tow tug or buggy

Validation of Phonon Physics in the CDMS Detector Monte Carlo

The SuperCDMS collaboration is a dark matter search effort aimed at detecting the scattering of WIMP dark matter from nuclei in cryogenic germanium targets. The CDMS Detector Monte Carlo (CDMS-DMC) is a simulation tool aimed at achieving a deeper understanding of the performance of the SuperCDMS detectors and aiding the dark matter search analysis. We present results from validation of the phonon physics described in the CDMS-DMC and outline work towards utilizing it in future WIMP search analyses.Comment: 6 Pages, 5 Figures, Proceedings of Low Temperature Detectors 14 Conferenc

The effect of forming parameters on the sheet stretch in incremental sheet forming (ISF) process on CNC lathe machine

The effect of forming parameters during the incremental sheet forming process (ISF) was studied for a circular shape sheet part. ISF is known as a rapid prototyping method to pro-duce sheet metal parts in a batch production series. ISF has found to be useful and advantageous which increases its application in industry. A CNC lathe machine was used in this study because it was easily programmed to move an indenter which worked as the tool, through the sheet metal which was clamped on a plain rounded mold. The work also investigated the influence of some process variables such as spindle speed, tool material; tool feed rate and temperature during the forming procedure. The results showed that a proper spindle speed and tool feed rate at some stage in the forming process improved the surface quality and the rate of penetration

Experimental Characterization of Space Charge in IZIP Detectors

Interleaved ionization electrode geometries offer the possibility of efficient rejection of near-surface events. The CDMS collaboration has implemented this interleaved approach for the charge and phonon readout for our germanium detectors. During a recent engineering run with negligible ambient radiation, the detectors were found to lose ionization stability more quickly than expected. This paper summarizes studies done in order to determine the underlying cause of the instability, as well as possible running modes that maintain stability without unacceptable loss of livetime. Additionally, first results are shown for the new version IZIP mask which attempts to improve the overall stability of the detectors.United States. Dept. of Energy (Grant DE-AC02-76SF00515)National Science Foundation (U.S.) (Awards 0705052, 0902182, 1004714, and 0802575

Circulating Tumour Necrosis Factor is highly correlated with brainstem serotonin transporter availability in humans

Preclinical studies demonstrate that pro-inflammatory cytokines increase serotonin transporter availability and function, leading to depressive symptoms in rodent models. Herein we investigate associations between circulating inflammatory markers and brainstem serotonin transporter (5-HTT) availability in humans. We hypothesised that higher circulating inflammatory cytokine concentrations, particularly of tumour necrosis factor (TNF-α), would be associated with greater 5-HTT availability, and that TNF-α inhibition with etanercept (sTNFR:Fc) would in turn reduce 5-HTT availability. In 13 neurologically healthy adult women, plasma TNF-α correlated significantly with 5-HTT availability (rho=0.6; p=0.03) determined by [123I] -beta-CIT SPECT scanning. This association was replicated in an independent sample of 12 patients with psoriasis/psoriatic arthritis (rho=0.76; p=0.003). Indirect effects analysis, showed that there was a significant overlap in the variance explained by 5-HTT availability and TNF-α concentrations on BDI scores. Treatment with etanercept for 6-8 weeks was associated with a significant reduction in 5-HTT availability (Z= 2.09; p=0.03; r=0.6) consistent with a functional link. Our findings confirm an association between TNF-α and 5-HTT in both the basal physiological and pathological condition. Modulation of both TNF-α and 5-HTT by etanercept indicate the presence of a mechanistic pathway whereby circulating inflammatory cytokines are related to central nervous system substrates underlying major depression

Process parameters for cylindrical deep drawing components

Sheet metal forming is one of the most important manufacturing processes in today’s industries, either to produce semi-finished or finished products. The demand for rapid, low-cost die fabrication and modification technology is greater than ever in sheet metal forming industry. Therefore, a great need for the development of both theoretical and experimental engineering methods which enables the problems to be tackled effectively; this is necessary to reduce production cost and to reduce the lead time between design and production. Due to recent development in numerical method technology, finite-element analysis has become one of the important tools in predicting the result of product deformation. With the intention to study the product failure which is the thinning effect, an experimental method has been developed to monitor the metal flow behaviour during the process. With this experiment, the actual product has been drawn with different draw depths, punch and die corner radii on mild steel and aluminium materials. Finally, the product wall thickness and diameter have been measured and data gained were interpreted into graph to visualise the influences of the process parameters such as draw depth, punch and die corner radius on the thinning effect. The results would give tool maker and tool designer guidance for selecting the best punch and die radius size in order to minimise the thinning effect on the drawn product

Comparison of CDMS [100] and [111] oriented germanium detectors

The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3" diameter $\times$ 1" thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.Comment: Low Temperature Detector 14 conference proceedings to be published in the Journal of Low Temperature Physic