LVDT

We investigated stem radial growth and water storage dynamics of 2 conifer species differing in hydraulic carbon strategies, Juniperus monosperma and Pinus edulis, under conditions of ambient, drought (∼45% reduction in precipitation), heat (∼4.8 °C temperature increase), and the combination of drought + heat, in 2013 and 2014. Juniper maintained low growth across all treatments. Overall, the relatively isohydric piñon pine showed significantly greater growth and water storage recharge than the relatively anisohydric juniper across all treatments in the average climate year (2014) but no differences in the regionally dry year (2013). Piñon pine ceased growth at a constant predawn water potential across all treatments and at a less negative water potential threshold than juniper. Heat has a greater negative impact on piñon pines' growth and water storage than drought, whereas juniper was, in contrast, unaffected by heat but strongly impacted by drought. The whole-plant hydraulic ...

Tulisan ini memaparkan hasil penelitian yang menghasilkan perangkat lunak yang dapat digunakan untuk memanfaatkan komputer (PC) sebagai osiloskop dengan menggunakan sound card sebagai antarmuka. Masukan diberikan melalui saluran Line in atau Mic In yang merupakan masukan audio dari sound card. Sinyal masukan dikonversikan oleh analog-to-digital converter (ADC) pada sound card. Hasil konversi kemudian dibaca oleh program untuk disajikan ke dalam bentuk gambar bentuk gelombang pada layar monitor. Perangkat lunak ini diimplementasikan dengan menggunakan bahasa pemrograman Delphi .

This paper discusses the functional system of a learning media product development; the design and implementation of a virtual lab with analog oscillator comprised of the following: i) Wien Bridge oscillator, ii) Colpitts oscillator, iii) Hartley oscillator and, iv) Astable Multivibrator. The virtual laboratory was built using Adobe Flash CS6 Action Script 3.0. This media can be accessed offline on a computer standalone based on the extension .exe or .swf and constructed with 24 frames per second (fps). This media can be operated by changing the Resistor (R), Inductor (L) and Capacitor (C) components via ‘plug and play’ to the tool-kit, or trainer kit, while the output can be seen in the measuring devices, namely: the frequnecy counter and oscilloscope. The second product is a digital jobsheet as a supplementary element for the practical, which contains prequisites for conducting practical use, introductory, and anatomic information of the virtual lab, as well as the directions for ...

High resolutions and positioning accuracies are often required in precision engineering and microsystems’ technologies. An experimental ultra-precision mechatronics system with long travel ranges is conceived in this work. The mechanical design of the system is optimized in order to achieve ultra-precision displacements. The control system of the device is integrated into a high-speed FPGA-based module as a virtual instrument (VI), where closed loop feedback is obtained by employing microstepping control. User controls are programmed as an independent Host VI. A linear incremental encoder with a sinusoidal output signal, which is interpolated and converted into a TTL signal, is employed for position feedback. Experimental validation of the achieved results is conducted by using laser interferometry. A set of short and long step point-to-point positioning experiments are performed and true sub-micron positioning repeatability and accuracy are obtained.

This paper presents a numerical analysis of prestressed hollow core slabs under long term loading. The model considers the time dependence of material and rheological properties in order to predict the actual stage of displacements, strains and stresses. It also takes into account load changes. For the analysis, each slab is divided in a finite number of bar elements, in which the cross section is described in concrete elements, parallel to the flexural axis, and prestressed steel elements. For the results evaluation, the effective concrete area is considered. The numerical results are compared with experimental tests performed on two series of prestressed hollow core slabs. Each series had a different geometry, rate and distribution of prestressing strands. Mid-span displacements were evaluated up to 127 days after initial loading. Good correlation was achieved with both series at and below the service load level.

In the present work the change in natural frequencies, damping and mode shapes of a prefabricated timber floor element have been investigated when it was integrated into a building structure. The timber floor element was first subjected to modal testing in laboratory with ungrounded and simply supported boundary conditions, and then in situ at different stages of building construction. The first five natural frequencies, damping ratios and mode shapes of the floor element and the entire floor were extracted and analysed. It may be concluded that the major change in natural frequencies occur as the floor element is coupled to the adjacent elements and when partitions are built in the studied room, the largest effect is on those modes of vibration that largely are constrained in their movement. The in situ conditions have a great influence on the damping, which probably depends on the damping characteristics of the supports, but also on the fact that the floor is integrated into the b...

Over 2 million children in the world suffer from sleeping disorders. The most common of these is Sleep Apnoea which may affect the child as early as on the first day of life. Sleep apnoea is a condition when the breathing rate of the patient lowers down drastically. The main problem that one faces is in the detection of the condition and hence delayed treatment. This paper describes the various types of Sleep Apnoea and a quick, effective and non-invasive method to detect the condition at hand.

Abstract—Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical experiments from anywhere and anytime, using a simple PC connected to the Internet. Nevertheless, given its valuable contribution to the teaching/learning process, the development of more infrastructures should continue, in order to make available more solutions able to improve ...

En este trabajo se analizan los problemas que suscita el tratamiento penal del apoderamiento de bienes encontrados en yacimientos arqueologicos por parte del descubridor. El objetivo es valorar que aporta a estos efectos el nuevo delito de expolio, introducido por la reforma de 2015, a la hora de afrontar esos problemas. El estudio tiene en cuenta la larga tradicion de incardinacion de esta conducta entre los delitos contra el patrimonio y los problemas concursales que se plantean con los delitos de danos sobre el patrimonio historico.

Abstract—Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical experiments from anywhere and anytime, using a simple PC connected to the Internet. Nevertheless, given its valuable contribution to the teaching/learning process, the development of more infrastructures should continue, in order to make available more solutions able to improve ...

In this project, we proposed design and implementation of car door latch testing machine. Nowadays cars are a very important part of this modern world because they give luxury and comfort. Even though they are comfortable, some problems always keep arising on the safety side. After a lot of research they rectified certain problems using air bags, auto parking, turbo charger ... etc. Likewise "car door latch" is also plays a major role in safety side in automobiles now we are going to discuss about one such problem that arises on the safety side. An unexpected accident occurs when people smash their fingers in between the car doors. Due to this kind of accident around 120,000 people are injured every year. But this was not taken as a very major safety concern for the customer. To avoid this kind accident due to car doors that we make sure of testing of car door latch using latch testing machine by analysing sealing factor, release travel, full release travel, latch opening current, release effort and testing position of the screw by using proximity sensor and to check the presence of the latch cover by using non-contact sensor (photo electric sensor). The working process of the "CAR DOOR LATCH TESTING MACHINE" is, when car door latch is placed in clamp cylinder that fix work piece in place. Then using servo motor actuator, the cylinder is moved forward to lock the latch and load cell is used to measure the sealing factor of car seal (rubber type) when the cylinder is moved in reverse direction. Release travel is measured using LVDT.

Aiming for teaching/learning support in sciences and engineering areas, the Remote Experimentation concept (an E-learning subset) has grown in last years with the development of several infrastructures that enable doing practical experiments from anywhere and anytime, using a simple PC connected to the Internet. Nevertheless, given its valuable contribution to the teaching/learning process, the development of more infrastructures should continue, in order to make available more solutions able to improve courseware contents and motivate students for learning. The work presented in this paper contributes for that purpose, in the specific area of industrial automation. After a brief introduction to the Remote Experimentation concept, we describe a remote accessible lab infrastructure that enables users to conduct real experiments with an important and widely used transducer in industrial automation, named Linear Variable Differential Transformer.

In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID and ramp control algorithms programmed as virtual instruments (VI) on an FPGA (Field Programmable Gate Array) module. User controls are programmed in an independent Host VI. A Linear Variable Differential Transformer (LVDT) is employed as a position feedback sensor, while positioning accuracy and repeatability are experimentally assessed by using a Michelson-type laser Doppler interferometric system. Different experiments with point-to-point positioning are conducted. In the first set of experiments, positioning with 100 μm steps is performed. In a second step, 10 mm positioning experiments are done. The system shows a marked nonlinearity when longer positioning steps are used; this nonlinearity influences significantly the output error. It is hence f...

The positive attributes of aluminium as a modern building material in construction practice have been used as background for a more intense application of this material type throughout the 21st century. Favourable properties of aluminium include most of the aspects of sustainability within the period of exploitation of the structure. One of the major problems with the application of aluminium in construction industry is the inherent fire resistance which needs further research if aluminium is to be more widely applied in construction practice. This paper describes research activities of an ongoing research project examining the mechanical and creep properties of aluminium alloy EN6082AW T6 exposed to fire. The research presented here is part of a joint research programme (the Croatian Science Foundation project No. UIP-2014-09-5711) conducted by the Universities of Split and Sheffield, whose aim is to explore the influence of creep on the behaviour of steel and aluminium columns in ...

The need of recording data and collect measurements taken by sensors is common to many applications and aims to facilitate the registration and monitoring of the development of events in various areas such as health, industry, meteorology, precision agriculture and others. However the electrical signals provided by sensors are not always directly capable of being manipulated which implies the need for adequacy of these signals so that they can be used in monitoring systems (data logger). In precision agriculture or phytomonitoring one of the sensors used for studies is designated as LVDT (Linear Variable Differential Transformer), which due to its characteristics require a signal processing system to facilitate its use. Thus this study aimed to demonstrate the development of an adequacy system of electrical signal to be used connected to a LVDT and to a data logger and thus provide the monitoring of crop development. The results showed that the system deals properly the signals repr...

In this paper a micropositioning mechatronics system is conceived and described. Its mechanical design is optimized in order to achieve high precision displacements. High speed closed-loop feedback control is obtained by using both PID and ramp control algorithms programmed as virtual instruments (VI) on an FPGA (Field Programmable Gate Array) module. User controls are programmed in an independent Host VI. A Linear Variable Differential Transformer (LVDT) is employed as a position feedback sensor, while positioning accuracy and repeatability are experimentally assessed by using a Michelson-type laser Doppler interferometric system. Different experiments with point-to-point positioning are conducted. In the first set of experiments, positioning with 100 μm steps is performed. In a second step, 10 mm positioning experiments are done. The system shows a marked nonlinearity when longer positioning steps are used; this nonlinearity influences significantly the output error. It is hence f...

A digital capacitance meter is a piece of electronic test equipment used to measure capacitance mostly of discrete capacitors. This project presents the design and implementation of asynchronous digital capacitance meter using the principle that when a capacitor is connected across a constant DC source, it charges at an exponential rate which is dependent on the capacitance of the capacitor seen by the source as well as the resistance seen by the capacitor in the circuit. In this research, an unknown capacitor whose capacitance is to be determined was used in the timing circuit of a 555-timer base monostable (One-shot) multivibrator to give out a single pulse whose ON duration is a function of the capacitor. This pulse was synchronized to a reference clock of frequency 7.2kHz using a positive edge-triggered D flip-flop to give a count enable signal to a decade counter and ensure that the count is stopped whenever it reaches the capacitance of the capacitor used in the timing circuit. The device was tested on different capacitors (both electrolytic and ceramic) and the results of the capacitance measurement show that the device was able to measure capacitors precisely within their dynamic range of values.

High pressure (HP) processing is an innovative process for food preservation mainly due the inactivation that pressure induces in microorganisms and/or enzymes. The correct design and optimization of HP processes requires knowledge of the volumetric properties of the foods and pressure fluids implicated in those processes. In this study, a cell capable of measuring volume variations caused by pressure and/or