Development of shear strength index test probe: its application on historic structures

PurposeMaterial properties, such as shear and compressive strength of masonry, have a crucial impact on the seismic analysis results of masonry structures. Considering that most of the historical buildings are masonry structures, the damage caused by obtaining shear strengths with known methods exceeds acceptable limits. Instead of traditional shear strength index tests, this paper presents a test technique that has been developed which causes less damage to the structure, to obtain mechanical properties in masonry structures.Design/methodology/approachA new approach to shear testing and a test probe has been developed to minimize the destructive effects of mechanical in situ testing on masonry structures. The comparison of the results obtained with reduced destruction level using the novel shear strength index test probe with those obtained from the traditional method is addressed. Masonry specimens were tested in the laboratory and in situ tests were carried out on 12 historical buildings.FindingsTest results obtained from the proposed probe shear strength index test were consistent with the results obtained from the conventional shear strength test both at the laboratory setting and in situ. Although a large number of data is needed for the validation of a method, satisfactory agreement with the conventional shear strength index test method was obtained.Originality/valueThe authors believe that the proposed method would give the opportunity to collect more mechanical strength data with much less destruction. The experimental work in the laboratory and in situ tests and their comparisons are the supportive and original values of this research.

Recording the braking process of a catastrophic flight data recorder protection cassette during a crash test

The article describes methods for recording the course of a test probe crashing into an obstacle in the form of a sand bed and the consequent rapid deceleration process by the braking object. The tested probe is adapted for placing a catastrophic flight data recorder protection cassette inside of it. The tests were conducted in order to confirm the resistance of the protection cassette to a g-load of 3400g acting on the cassette for ca. 6.5 ms, as per the guidelines of the standards: European EuroCAE ED-112 and Polish NO-16-A200. The probe was accelerated to a required velocity using a DPZ-250 pneumatic can-non, owned by the Institute of Aviation. The controlled braking pro-cess was obtained thanks to a sand bed located within the braking station, which was designed and constructed at Air Force Institute of Technology (AFIT). The course of each crash test, that is, the flight and the process of a test probe crashing into the sand was recorded by a camera for recording fast transient phenomena. Conducting the crucial tests involved installing an overload recording system inside the test probe, which directly records and saves the overloads associated with collisions. The objective of the first test stage was to confirm the correctness of the adopted methodology and to develop test procedures used in further experiments. The essential tests involved in-stalling a catastrophic flight data recorder electronics package inside the test probe in order to confirm satisfying the requirement in terms of overload. The executed tests confirmed reaching the parameters of the experiment, which satisfy the normative requirements of the test conditions. The checks of the tested catastrophic flight data recorder elements proved its resistance to a g-load of 3400 g. The applied g-load re-cording methods enabled the inspectors to confirm reaching the required value and the nature of changes of the hazards, the test probe was subjected to during the impact tests.

A Turn-On Fluorescent Probe for Sensitive Detection of Cysteine in a Fully Aqueous Environment and in Living Cells

We reported here a turn-on fluorescent probe (1) for the detection of cysteine (Cys) by incorporating the recognition unit of 2,4-dinitrobenzenesulfonyl ester (DNBS) to a coumarin derivative. The structure of the obtained probe was confirmed by NMR and HRMS techniques. The probe shows a remarkable fluorescence off-on response (∼52-fold) by the reaction with Cys in 100% aqueous buffer. The sensing mechanism was verified by the HPLC test. Probe 1 also displays high selectivity towards Cys. The detection limit was calculated to be 23 nM. Moreover, cellular experiments demonstrated that the probe is highly biocompatible and can be used for monitoring intracellular Cys.

IC Test Probe Measurement System

Integrated-Circuit (IC) test probes have been designed variously and manufactured flexibly cause of diverse IC packaged forms. To successfully test the functions of the packaged IC, the packaged industry should carefully select a suitable probe type based on the size or pitch of the ball and the lead of the packaged IC. One plunger of the probe is used to be connected with the packaged IC; the other plunger is connected to the testing devices. A probe basically is composite of a barrel and two plungers whose head might be the crown or the pierced type. The main diameter of the probe’s barrel varies from 0.2 millimeter to 0.6 millimeter; the total length of the probe could be from 1 millimeter to 7 millimeter. The probes ought to be detected before implanting them into the housing socket. However, the presenting probe measure method, eye checking by human beings, cannot fulfill the diverse types of probes because the size of IC becomes more delicate and smaller. This paper aims to develop an intelligent system that can detect and recognize more than ten items of a probe. The experimental results demonstrate that the proposed system can effectively measure the different probes.