Preliminary Laboratory Tests Research Articles

The control algorithm of a programmable tandem detonator

The article describes the results of laboratory tests of the algorithm of control of programmable detonators designed for tandem systems. Control elements were made on the basis of microcontrollers using RISC architecture. The detonator has a system to quickly excite the precursor charge and can be programmed at any time to delay the detonation of the main charge. The lack of delay in excitation of the precursor charge was realized using a comparator. The article presents the results of preliminary laboratory tests of the control algorithm of the executed system. The flexibility of the solution to program any delay time for the excitation of the main load provides a wide range of practical applications.

Digital Signal Processor Based Device for Measurement of Return Stroke Currents of Lightning Strikes to Tall Structures: First Experimental Results

This article describes the features of a device developed for measurement and recording of waveforms of first return stroke currents of lightning flashes striking tall grounded structures. The operation of this device is based on the detection of the voltage induced along a loop by the fast-varying magnetic field produced by the current flowing along the structure close to the device. A digital signal processor supports the data acquisition. The device includes means for remote internet access, self-test, and data transfer. Preliminary laboratory tests consisting of the measurement of impulsive currents intended to resemble first return stroke currents, using both the device and a reference measuring system, were performed. They allowed the analyzing of the source of differences and improving the system performance. After that, the device was installed at Morro Cachimbo Station, Brazil. The waveforms of three first return stroke currents have been recorded since then and the results showed to be consistent with those obtained by the accurate measuring system of the instrumented tower. The application of a network of this low-cost device is worth developing the regional database of lightning current parameters, and providing ground-truth references for calibrating lightning locations systems.

AEGIS – Mobile Device for Generating Electromagnetic Curtain for Special Applications and Countering the Threats of RCIED

In the article the concept, design and realization of the technological demonstrator of a mobile device for generating an electromagnetic curtain (with a name AEGIS) were presented, both in the hardware and software areas. The device is designed to block the radio communication which allow detonating the Radio Controlled Improvised Explosive Devices (RCIEDs). The preliminary laboratory tests of the demonstrator for generating the jamming signal, that were presented in the paper, aimed at assessing the correctness of the device operation and verification of generated signal parameters. On the basis of the obtained results, the ability to jam the cellular systems as well as other radio devices operating in the frequency band from 400 MHz to 2700 MHz was assessed.

Monitoring of thermo-hydrological behavior in Green Infrastructure

The multi-purpose nature of Sustainable Drainage Systems (SuDS) or Green Infrastructure (GI) presents a significant opportunity to store or recover heat for low carbon urban heating/cooling systems. The capacity of such systems for energy storage is strongly dependent on the thermal and hydrological boundary conditions, estimation of their feasibility requires a deep understanding of how atmospheric conditions and the near-surface hydrological regime affect heat transfer. A large-scale, outdoor lysimeter has been set up at the (UK) National Green Infrastructure Facility in order to monitor the influence of atmospheric conditions on hydrological and thermal properties of SuDS. Volumetric water content, matric suction and temperature were monitored at various depths and locations within the sand and topsoil layer. Additionally, thermal conductivity at multiple depths, and heat flux at the surface and bottom boundary were measured. Results of the initial monitoring phase, as well as, preliminary laboratory tests are presented herein and demonstrate the complex interaction between partial saturation and heat transfer. Further work investigates the effects of rainfall and heat injection using rainfall simulation and a variable-power heating cable, respectively.

Towards Creation of Ceramic-Based Low Permeability Reference Standards

Low-permeable materials, either artificial or natural, are essential components of the current technological development. Their production or processing requires a comprehensive characterization method based on confident reference standards. Permeability standards for values below 10−15 m2 are lacking. In this study, we explored the feasibility of using the ceramic sintering process to reach low, but measurable values of gas permeability in Al2O3 samples, as one of the potential materials for reference standards. The studied samples were produced with a ceramic 3D printer, which enables the manufacturing of low-permeable samples having complex geometrical arrangements. A series of preliminary laboratory testing indicated the available gas permeability range from 2.4 × 10−15 m2 for the pre-sintered samples to 1.8 × 10−21 m2 for the sintered samples. The verification of the permeability reduction was carried out using a unique unsteady state fast and accurate measurement method. The results confirm the possibility of developing a technology for materials manufacturing with low porosity and permeability. Such materials open many areas for application, including manufacturing of ceramics with controlled transport properties and low-permeability standards for calibrating laboratory equipment for geosciences, construction industries, biomedical, and other relevant fields.

Multi-scale surface patterning – an approach to control friction and lubricant migration in lubricated systems

Purpose The paper aims to investigate the possibilities to control friction in lubricated systems by surface patterning, making use of a multi-scale approach. Surface patterns inside the tribological contact zone tend to directly reduce friction, whereas surface patterns located in the close proximity of the contact area can improve the tribological performance by avoiding lubricant starvation and migration. Finally, optimized surface patterns were identified by preliminary laboratory tests and transferred to a journal bearing, thus testing them under more realistic conditions. Design/methodology/approach Surface patterns on a large scale (depth > 10 µm) were fabricated by micro- and roller-coining, whereas surface patterns on a small scale (depth < 2 µm) were produced by direct laser interference patterning. The combination of both techniques resulted in multi-scale surface patterns. Tribologically beneficial surface patterns (verified in ball-on-disk laboratory tests) were transferred onto a journal bearing’s shaft and tested on a special test-rig. To characterize the lubricant spreading behavior, a new test-rig was designed, which allowed for the study of the lubricant’s motion on patterned surfaces under the influence of a precisely controlled temperature gradient. Findings All tested patterns accounted for a pronounced friction reduction and/or an increase in oil film lifetime. The results from the preliminary laboratory tests matched well, with results from the journal bearing test-rig, both tests showing a maximum friction reduction by a factor of 3-4. Numerical investigations, as well as experiments, have shown the possibility to actively guide lubricant over patterned surfaces. Smaller periodicities, as well as greater structural depths and widths, led to a more pronounced anisotropic spreading and/or greater spreading velocities. Multi-scale surfaces demonstrated the strongest effects regarding the lubricant’s spreading behavior. Originality/value Friction, as well as lubricant migration, can be successfully controlled by using micro-coined, laser-patterned and/or multi-scale surfaces. To the best of the authors’ knowledge, the study demonstrates for the first time the unique possibility to transfer results obtained in laboratory tests to a real machine component.

Concrete slab fragmentation after bullet impact: An experimental study

The response of nonreinforced concrete to high-speed flying fragments depends on many factors such as composition, geometry and boundary conditions of the obstacle. In this study, the authors verified experimentally a series of concrete slabs with various aggregate types and amounts of steel reinforcement. The material properties were previously developed and verified during the laboratory experiments with standard cubic specimens. Moreover, the main goal of this research was the verification of high-strength concrete plates using different kinds of aggregate, that is, traditional gravel, granite, basalt and amphibolite subjected to the military bullet impact. It is known that the aggregate filled about 70% of total concrete volume, and therefore, the properties of aggregate, like density, strength and surface will be the main factors influencing the concrete strength and further concrete resistance to projectiles. The research presented shows that the type and shape of aggregate determined the conditions of concrete failure. The outcomes show that the obtained compressive strength varied between 60 and 80 MPa. In the second stage of the test, randomly distributed reinforcement was added to selected concrete mixtures. Hooked steel fibres with an aspect ratio of 50 in the amounts of 50 and 100 kg per cubic metre were applied. The influence of steel fibres on the concrete properties was verified in compressive and splitting strength tests. On the basis of preliminary laboratory tests, the final slab specimens, with the dimensions of 0.5 × 0.5 m and 0.05 m thickness, were produced. The final verification was performed in the real field conditions using the most popular military bullet, whose kinetic energy was more than 2000 J. The measurements of the initial and final velocities of the bullets and concrete fragments were obtained using high-speed camera measurement equipment. The final failure of the slabs was presented as the primary outcome.

Diamidoamine Salt as the Admixture for Concrete Increasing the Resistance to the Freeze-Thaw Cycle

Concrete freeze-thaw resistance, along with compressive strength, is one of its basic features, which have a significant impact on the durability of structures of buildings and engineering structures. Numerous studies presented in domestic and foreign literature showed that there is a relationship between the concrete mix’s composition and the extent of frost damage. The frost durability of concrete depends on many factors. Therefore, cyclic changes of air temperature in winter conditions (over 100 freeze-thaw event cycles per year are estimated in Poland) must be taken into consideration as soon as in the phase of designing a concrete mix and structural elements. Proper designing of the concrete mix, optimal selecting of proportions and kinds of components, applying of appropriate kinds of additives and admixtures as well as proper maintenance of concrete can protect the investor against serious financial consequences. The paper discussed the influence of sub-zero temperatures effect on cement concretes properties. The requirements that are imposed on designers in terms of concretes resistance to frosts cyclic effect by the currently applicable standards were presented. The paper also presents the results of an original research programme showing the effectiveness of diamidoamine salt as an admixture for concretes that increases their resistance to the freeze-thaw cycle. Within the preliminary tests, the influence of the diamidoamine salt on early and 28-day compressive strength was marked. The air content in fresh concrete, absorbability and water permeability were also specified. The freeze-thaw resistance of concretes with the addition of the diamidoamine salt after 50 freeze-thaw cycles was determined. The conducted preliminary laboratory tests showed that applying the diamidoamine salt causes the decrease in compressive strength. This decrease is proportional to the admixture content. The applied admixture significantly decreases the absorbability, improves waterproofness and freeze-thaw resistance of the concrete.

Suspension-colloidal flow accompanied by detachment of oversaturated and undersaturated fines in porous media

Mechanical equilibrium of particles attached to rock during flow is defined as torque balance of attaching and detaching forces. Oversaturated state of fines means that detaching torque exceeds the attaching torque, and fines detach as the flow starts. In undersaturation, the attaching torque dominates the detaching torque, and fines mobilisation can occur only if there is either additional detaching torque or a weakening of the attaching torque. Preliminary laboratory tests determine the mechanical equilibrium velocity and salinity, to ensure that oversaturation or undersaturation can be readily reproduced in further corefloods. We formulate the basic governing equations and derive exact solutions for over and undersaturated cases. The exact solutions allow formulating the fingerprints for transport of oversaturated and undersaturated fines in porous media. The coreflood results reveal the characteristic features of the oversaturated case of fines migration. Moreover, the analytical modelling results are found to be in high agreement with the experimental data, under the typical values of the fitted model coefficients.

Preliminary laboratory tests of a new fibre optic high temperature measurement device

Preliminary laboratory tests of a new fibre optic high temperature measurement device

Active Dielectric Window: A New Concept of Combined Acoustic Emission and Electromagnetic Partial Discharge Detector for Power Transformers

The detection and location of partial discharge (PD) is of great significance in evaluating the insulation condition of power transformers. This paper presents an active dielectric window (ADW), which is a new concept of combined acoustic emission (AE) and electromagnetic PD detector intended for assembly in a transformer’s inspection hatch. The novelty of this design lies in the fact that all structural components of an ultrasonic transducer, i.e., the matching and backing layer, an active piezoelectric element with electrodes, and electrical leads, were built into a dielectric window. Due to the fact that its construction was optimized for work in mineral oil, it is characterized by much higher sensitivity of PD detection than a general-purpose AE sensor mounted outside a transformer tank. Laboratory tests showed that the amplitude of the AE pulses generated by creeping discharges, which were registered by the ADW, was around five times higher on average than the pulses registered by a commonly used contact transducer. A possibility of simultaneous detection of acoustic and electromagnetic pulses (with an integrated ultra-high frequency (UHF) antenna) is an important advantage of the ADW. It allows for an increase in the reliability of PD detection, the accuracy of defect location, and the effectiveness of disturbance identification. This paper describes in detail the applied methods of designing and modeling the ADW components, the manufacturing process of the prototype construction, and the results of preliminary laboratory tests, in which the detector’s sensitivity as well as the efficiency of the PD source location were evaluated.

СТАНЦИЯ АВТОМАТИЧЕСКОГО ВЕРТИКАЛЬНОГО ЗОНДИРОВАНИЯ ПРИБРЕЖНОЙ ЗОНЫ МОРЯ НА ОСНОВЕ ДОННОЙ ЛЕБЕДКИ

This model provides a periodic measurement of temperature profiles from the bottom layer to the water surface in a programmable mode using temperature and pressure sensors placed in a single streamlined body (probe). The probe is connected by a thin resistant cable to the bottom block of the station, including a winch and an electronic unit. This cable provides power to the probe sensors, and transmits data to the station’s solid-state memory. Initially, the cable is wound on the winch drum, and the probe is located near the bottom block of the station. The probe has positive buoyancy. When turning on the winch to unwind the cable, the probe starts to go up. After it reaches the water surface and stays there for a short time, the winch turns back, the cable is wound onto the drum, and the probe is pulled down until it reach the bottom block. Measurements of parameters are carried out when the probe moves up and down with fine-scale vertical resolution. During regular use of the station in the water area of the IO RAS Gelendzhik Research Site on the Black Sea, the measurement data will not only be recorded in the station’s memory, but also promptly transmitted to the coastal center via a cable laid across the sea floor. This cable will also provide power to the station. Preliminary laboratory and field tests of the main components of the station are conducted. In the developed version, the station is designed for long-term monitoring of the hydrological structure of the marine coastal zone in operative mode. It may be retrofitted with bio-optic and hydrochemical sensors for environmental monitoring of reservoirs, the depth of which does not exceed 50-100 m.

Preliminary studies on the use of Fenton reagent to reduce pollution from wastewater from the production of household chemicals

Abstract Industrial sewage from the production of household chemicals contain large amounts of impurities in the form of ionic and non-ionic surfactants, detergents, active extenders, enzymes. The mixture of these components means that the reduction of pollutants from this type of waste-water is very burdensome. The article presents the results of preliminary laboratory tests of the possibility of using Fenton reaction in the reduction of pollution in wastewater from the household chemistry industry. The reduction of impurities was determined by the concentration of COD. The tests were carried out on samples of wastewater taken from an industrial wastewater treatment plant from the production of household chemistry. A pollution reduction of 24.7–32.3% was achieved. On the basis of the preliminary tests carried out, the need to better match the doses of reagents to carry out pollution reduction was determined. Despite obtaining values exceeding the limit values for introducing this type of sewage into the sewage system and into the environment, the conducted tests can be considered as prognostic. To compare the process carried out on industrial waste-water, a reduction of impurities was carried out using the Fenton reagent in the standard phenol solution.

Development of anti-icing airfield pavement using surface-embedded heat wire

ABSTRACTSnow and ice pose a significant risk for aircraft ground operation safety. Ploughing and chemical treatment are used for snow removal, but yield long-term detrimental impacts to the airfield infrastructure and environment. A proof-of-concept airfield heated pavement system (AHPS) prototype using near-surface embedded heat wire for pavement anti-icing is presented in this paper. Surface-embedded wires were used to study heat performance and energy warranted to maintain above-freezing slab surface temperatures. This approach concentrated heat energy to the pavement surface. Testing this AHPS prototype contained the following objectives: (1) optimise surface-embedded heat wire configuration, (2) investigate surface temperature distribution and (3) summarise system heating performance in outdoor winter conditions. Preliminary laboratory testing used a 150 mm wire spacing in a serpentine configuration. At this spacing, an energy flux of 142 W/m2 produced a 6°C temperature rise in 6 h in a −14°C freezer chest. Sufficient surface temperature rise was attained in preliminary field-testing during the 2015–2016 winter season using a 213.1–697.5-W/m2 energy range. Using the presented AHPS prototype, a 25-mm layer of crushed ice melted within 1 h during an experimental ice test.

Prototyping and Validation of MEMS Accelerometers for Structural Health Monitoring—The Case Study of the Pietratagliata Cable-Stayed Bridge

In recent years, thanks to the simple and yet efficient design, Micro Electro-Mechanical Systems (MEMS) accelerometers have proven to offer a suitable solution for Structural Health Monitoring (SHM) in civil engineering applications. Such devices are typically characterised by high portability and durability, as well as limited cost, hence resulting in ideal tools for applications in buildings and infrastructure. In this paper, original self-made MEMS sensor prototypes are presented and validated on the basis of preliminary laboratory tests (shaking table experiments and noise level measurements). Based on the well promising preliminary outcomes, their possible application for the dynamic identification of existing, full-scale structural assemblies is then discussed, giving evidence of their potential via comparative calculations towards past literature results, inclusive of both on-site, Experimental Modal Analysis (EMA) and Finite Element Analytical estimations (FEA). The full-scale experimental validation of MEMS accelerometers, in particular, is performed using, as a case study, the cable-stayed bridge in Pietratagliata (Italy). Dynamic results summarised in the paper demonstrate the high capability of MEMS accelerometers, with evidence of rather stable and reliable predictions, and suggest their feasibility and potential for SHM purposes.

From lab to application - Improved frictional performance of journal bearings induced by single- and multi-scale surface patterns

Abstract The present study experimentally examines the effect of selected single-scale and multi-scale surface patterns fabricated by roller-coining and/or direct laser interference patterning on the frictional performance of journal bearings. For this purpose, surface patterns showing beneficial effects in preliminary laboratory tests were selected and fabricated onto the shaft of journal bearings made of stainless steel (AISI 304). The frictional performance of these patterns was evaluated on a special test rig by recording Stribeck-like curves. The results show greatly reduced coefficients of friction and a shift in the transition from mixed to hydrodynamic lubrication to smaller rotational speeds for all patterned samples compared to the reference sample. The observed friction reduction matches well with results observed in the previous laboratory tests.

Preliminary Tests for Ti-Mo-Zr-Ta Alloys as Potential Biomaterials

Nowadays, there is a continuing concern for the research and development of alloys for medical and biomedical applications. In order to check the biocompatible character of a new Ti-Mo-Zr-Ta alloys, it is necessary to carry out preliminary laboratory tests to follow how a biomaterial surface would interact with the host. The paper presents tests for Ti-Mo-Zr-Ta alloys like contact angle and DSC test to identify biocompatible character. Contact angle measurement is an experimental technique used to assess the hydrophilic or hydrophobic character of surfaces by reference to the 90º contact angle value and to characterize the thermal behavior, for temperature range between 36.5-37.2ºC, interval which a biomaterial works inside the healthy human body, was used DSC test.

Metarhizium anisopliae against Prosoestus Spp., Pests of Female Oil Palm Inflorescences: Preliminary Laboratory Tests

Metarhizium anisopliae against Prosoestus Spp., Pests of Female Oil Palm Inflorescences: Preliminary Laboratory Tests

Prognostic Value of IL-10 and Its Relationship with Disease Stage in Iranian Patients with Multiple Myeloma

Background:Several studies have demonstrated roles of interleukins in the pathogenesis of multiple myeloma (MM).Objective:Here we considered correlations among serum levels of IL-10, stage of disease and clinical laboratory disease markers in Iranian MM patients to investigate whether the interleukin might have prognostic significance.Materials and Methods:In this cross-sectional study, a total of 60 subjects (40 patients and 20 controls) were recruited. After preliminary laboratory tests, disease stage was evaluated and serum levels of IL-10 were measured using an enzyme-linked immunosorbent assay (ELISA).Results:The mean concentration of serum IL-10 in patients (2.39±0.82 ng/ml) was significantly higher (p<0.0001) than that in healthy controls (0.34±0.15 ng/ml). A positive and significant correlation (p<0.0001) was observed with the disease stage. The highest plasma cell proportions were recorded for MM stage III patients (68.8±9.21%), differing significantly from those of stage I patients (50.0±10.0%; p=0.011). The Beta-2 microglobulin value in stage III patients (7.7±1.13mg/l) was significantly higher than in those with stage II (4.31±0.64 mg/l; p<0.0001) and stage I (2.8±0.4 mg/l; p<0.0001). There was also a positive and significant correlation (p=0.002) between IL-10 levels and B2M. A trend (p=0.06) for positive correlation was observed between IL-10 levels and plasma cells.Conclusions:The correlation of IL-10 with disease stage and markers of disease activity indicates important roles in MM pathogenesis and progression. Therefore, measurement of serum IL-10 might be helpful for predicting stage and clinical management of MM.

Smart-Spider: Autonomous Self-driven In-line Robot for Versatile Pipeline Inspection

This paper presents the design and development of a conceptual prototype of an autonomous self-driven inline inspection robot, called Smart-Spider. The primary objective is to use this type of robot for offshore oil and gas pipeline inspection, especially for those pipelines where the conventional intelligent pigging systems could not or be difficult to be deployed. The Smart-Spider, which is real-time controlled by its own on-board MCU core and power supplied by a hugged-up battery, is expected to execute pipeline inspection in an autonomous manner. A flexible mechanism structure is applied to realize the spider’s flexibility to adapt to different diameters of pipelines as well as to handle some irregular situations, such as to pass through an obstacled areas or to maneuver at a corner or junction. This adaption is automatically controlled by the MCU controller based on pressure sensors’ feedback. The equipped devices, such as the selected motors and battery package, as well as the human-and-machine interface are also discussed in detail. Some preliminary laboratory testing results illustrated the feasibility and cost-effective of this design and development in a very promising manner.