Contribution of Electrolysis within an Integrated System for a Poultry Slaughterhouse Wastewater Treatment

Treatment of poultry slaughterhouse wastewater before disposal or reuse is an essential part of human health and environmental protection in general. This study aimed to investigate the influence of the pre-treatment system based on electrolysis technology within an integrated lab-scale treatment plant in the removal of contaminants from poultry slaughterhouse wastewater. Several treatment units (averaging tank, feather catcher, fat catcher, and coarse mechanical filter) were connected in series before the electrolysis chamber. While in general, the entire integrated system also included some other units such as ultra-filtration, reverse osmosis, and the ultraviolet lamp connected in series. From the analysis results, it was observed that the pre-treatment phase with electrolysis had a significant influence on the general performance of the treatment plant. The pre-treatment contributed to about 33.5% to 100% in the general contaminants’ removal efficiency. The highest contribution was observed from the total chlorine (100%), nitrate (98.2%), as well as BOD (95.3%). The lowest contribution was observed from the nitrite removal, with 33.5%. This study revealed further that the integration of electrolysis technology in a wastewater treatment system has a significant potential for developing an effective wastewater treatment plant.

A Study of Longitudinal Waveguide with Band Gap Using Cylindrical and Conical Shape Periodic Structure

This research presents the theoretical and experimental studies for cylindrical and conical periodic structures to control longitudinal wave motion. Many relevant researches exist to stop and pass a certain frequency wave without active devices with periodic structures called metamaterials. To modify or control longitudinal wave propagation, i.e., passing or blocking mechanical wave within specific frequency ranges, repeated mass-spring systems or metamaterials can be applied. By integrating a few identical structural components to form a whole structure, it is possible to make a mechanical filter for wave propagation. Most studies rely on straight bar with cylindrical structure. Thus, with a unit cell that have a cylindrical and conical structure, this research presents the extensions toward the studies of the wave motions for straight and curved bars with finite element simulations and experiment studies. The results show that the hybrid cylindrical and conical periodic structures can be effective in terms of wave motion control and stiffness.

Vibration of Periodic Drill-Strings with Local Sources of Resonance

A new class of drill-strings is proposed for attenuating undesirable vibrations to ensure effective operation. The drill-string is provided with passive periodic inserts, which are integrated with sources of local resonance (LR). The inserts make the drill-string act as a low frequency pass mechanical filter for the transmission of vibration along the drill-string. Proper design of the periodic inserts with sources of LR tend to shift these stop bands towards zones of lower frequencies to enable confining the dominant modes of vibration of the drill-string within these bands. In this manner, propagation of the vibration along the drill-string can be completely blocked. A finite element model (FEM) is developed using ANSYS to investigate the bandgap characteristics of the proposed drill-string with sources of LR. The developed FEM accounts for bending, torsional, and axial vibrations of the drill-string in order to demonstrate the effectiveness of the periodic inserts with LR in simultaneous control of these combined modes as compared to conventional solid periodic inserts, which are only limited to controlling bending vibrations. The effect of the design parameters of the periodic inserts with LR on the bandgap characteristics of the drill-string is investigated to establish guidelines of this class of drill-strings.

The Role of Filter with Different Media Compositions on Water Quality and Survival of Pangasius (Pangasius sp.) in Recirculation Aquaculture System

The high market demand for Pangasius (Pangasius sp.) has encouraged farmers to adopt a cultivation system with high stocking densities and high feeding rates. This causes fish farming waste to increase and ammonia in the waters also increases, resulting in a decrease in water quality. One of the efforts to overcome this problem is by using Recirculation Aquaculture System (RAS). This study aims to examine the effect of filters with different media compositions in RAS of Pangasius. Test fish, average weight of 4.59 g, kept for 30 days in aquarium with a density of 1.15 g.L-1. The feed is given at satiation, twice a day. There were five treatments and four replications during study. The treatments were the difference composition of filter media, i.e. A (100% zeolite), B (25% net + 75% zeolite), C (50% net + 50% zeolite), D (75% net + 25% zeolite), and E (100% net). Dacron was used as a mechanical filter in all treatments. The results showed that the composition of different filter materials had a significant effect (P <0.05) on Survival Rate (SR), Total Amount of Feed Fed (TFF), Relative Growth Rate (RGR), and Feed Conversion Efficiency (FCE). The best performance was showed by media biofilter composition of 25% nets + 75% zeolite, with the value of VTR (Volumetric Total Ammonia Nitrogen Removal) were 55.45-66.32 g.m-3.day-1, SR was 93.75%; TFF was 124.84 g; RGR was 2.13%.day-1, and FCE was 46.87%. Various different compositions of net and zeolite as filter media on RAS were able to manage TAN below tolerance limit.Keywords: catfish, recirculation system, filter composition, dacron, net, zeolite.

Design and Modeling of a Parallel Continuum Manipulator for Trunk Motion Rehabilitation

The objective of the present work is to develop a device for training the trunk balance and motion during the early stage of rehabilitation of patients who have suffered a stroke. It is coupled to a standing frame and is based on a parallel continuum manipulator where a wearable jacket is moved by four flexible limbs actuated by rotary motors, achieving the translation and rotation required in the trunk to perform a given exercise. The flexible limbs act as a natural mechanical filter in such a way that a smooth physiological motion is achieved, and it feels less intimidating to the patient. After measuring the kinematic requirements, a model has been developed to design the system. A prototype has been built and a preliminary experimental validation has been done where the jacket generates translation coupled to a rotation around the anteroposterior, medio-lateral and longitudinal axis. The measurements of the motors torque and the force sensors located in the flexible limbs have been compared with the simulations from the model. The results prove that the prototype can accomplish the motions required for the rehabilitation task, although further work is still required to control the interaction with the patient and improve the performance of the device.

ADAPTIVE MECHANICAL FILTER FOR PIEZOELECTRIC ACCELEROMETER

When conducting dynamic tests, when simulating shock effects, the measurement system - from the sensor to the data acquisition unit is subject to significant overloads. In this circuit, the accelerometer is the most vulnerable link. Therefore, piezoelectric accelerometers have become widely used in measuring shocks as more reliable and durable, but they also have a number of disadvantages. Thus, under broadband vibration effects, excitation in the region of mechanical resonance is observed. That is, the material of the sensor crystal may not have an excessive mechanical load, but generate a large amount of output charge due to the resonance of the sensor. This increases the electrical signal and can lead to saturation or, in many cases, damage to the signal shapers and amplifiers following the sensor. The result of such modes of operation is the loss of data due to the displacement of direct current over time. There is often a shift of the zero level of the output signal. When piezoelectric elements are in resonance, there may be a relative displacement of the sensing element. This state of overload leads to the appearance of parasitic output charges, which leads to a change in the generated charge in a short period of time. Due to mechanical overload, under the action of high-intensity shocks, physical destruction of the sensor is also possible. In many cases, the use of mechanical filters made of viscoelastic materials, which are placed between the object of measurement and the piezoelectric accelerometer (sensor), prevents the undesirable consequences of these shortcomings and improves the process of measuring shocks. The use of mechanical filters made of viscoelastic materials makes it possible to significantly reduce the amplitude of oscillations of the piezoelectric accelerometer (over -12 dB) and shift its resonant frequency towards higher frequencies. That is, the use of mechanical filters significantly reduces the mechanical load on the sensor, which makes the process of measuring vibration (especially shock) more predictable.

Vectorchip: Microfluidic platform for highly parallel bite by bite profiling of mosquito-borne pathogen transmission

Mosquito bites transmit a number of human pathogens resulting in potentially fatal diseases including malaria, dengue, chikungunya, West Nile encephalitis, and Zika. Although female mosquitoes transmit pathogens via salivary droplets deposited during blood feeding on a host, very little is known about the genomic content of these nanoliter scale droplets, including the transmission dynamics of live pathogens. Here we introduce Vectorchip, a low-cost, scalable microfluidic platform for molecular interrogation of individual mosquito bites in a high-throughput fashion. An ultra-thin PDMS membrane coupled to a microfluidic chip acts as a biting interface, through which freely-behaving mosquitoes deposit saliva droplets by biting into isolated arrayed micro-wells enabling molecular interrogation of individual bites. By modulating membrane thickness, the device enables on-chip comparison of biting capacity and provides a mechanical filter allowing selection of a specific mosquito species. Utilizing Vectorchip, we show on-chip simultaneous detection of mosquito DNA as well as viral RNA from Zika infected Aedes aegypti mosquitoes – demonstrating multiplexed high-throughput screening of vectors and pathogens. Focus-forming assays performed on-chip quantify number of infectious viral particles transmitted during mosquito bites, enabling assessment of active virus transmission. The platform presents a promising approach for single-bite-resolution laboratory and field characterization of vector pathogen communities, to reveal the intricate dynamics of pathogen transmission, and could serve as powerful early warning artificial “sentinel” for mosquito-borne diseases.

The Use of UVC Irradiation to Sterilize Filtering Facepiece Masks Limiting Airborne Cross-Infection

In addition to looking for effective drugs and a vaccine, which are necessary to save and protect human health, it is also important to limit, or at least to slow, the spread of coronavirus. One important element in this action is the use of individual protective devices such as filtering facepiece masks. Currently, masks that use a mechanical filter, such as a HEPA (High Efficiency Particulate Air) filter, are often used. In some countries that do not have a well-developed healthcare system or in exceptional situations, there is a real and pressing need to restore filters for reuse. This article presents technical details for a very simple device for sterilization, including of HEPA polymer filters. The results of biological and microscopic tests confirming the effectiveness of the sterilization performed in the device are presented. The compact and portable design of the device also allows its use to disinfect other small surfaces, for example a small fragment of a floor, table, or bed.

Permanent Bilateral Carotid Filters for Stroke Prevention in Atrial Fibrillation

Purpose of Review A novel permanent carotid filter device for percutaneous implantation was developed for the purpose of stroke prevention. In this review, we cover rationale, existing preclinical and clinical data, and potential future directions for research using such a device. Recent Findings The Vine™ filter was assessed for safety in sheep and in 2 observational human studies, the completed CAPTURE 1 (n = 25) and the ongoing CAPTURE 2 (planned n = 100). CAPTURE 1 has shown high procedural and long-term implant safety. A control group was not available for comparison. Summary A mechanical filter for permanent stroke prevention can be implanted bilaterally in the common carotid artery safely and efficiently. A randomized trial is planned for 2021 (n = 3500, INTERCEPT) to demonstrate superiority of a filter + anticoagulation strategy over anticoagulation alone in patients at high risk for ischemic stroke.