Internal Chamber Research Articles

Puffball-Inspired Microrobotic Systems with Robust Payload, Strong Protection, and Targeted Locomotion for On-Demand Drug Delivery.

Microrobots are recognized as transformative solutions for drug delivery systems (DDSs) because they can navigate through the body to specific locations and enable targeted drug release. However, their realization is substantially limited by insufficient payload capacity, unavoidable drug leakage/deactivation, and strict modification/stability criteria for drugs. Natural puffballs possess fascinating features that are highly desirable for DDSs, including a large fruitbody for storing spores, a flexible protective cap, and environmentally triggered release mechanisms. This report presents a puffball-inspired microrobotic system which incorporates an internal chamber for loading large drug quantities and spatial drug separation, and a near-infrared-responsive top-sealing layer offering strong drug protection and on-demand release. These puffball-inspired microrobots (PIMs) display tunable loading capacities up to high concentrations and enhanced drug protection with minimal drug leakage. Upon near-infrared laser irradiation, on-demand drug delivery with rapid release efficiency is achieved. The PIMs also demonstrate translational motion velocities, switchable motion modes, and precise locomotion under a rotating magnetic field. This work provides strong proof-of-concept for a DDS that combines the superior locomotion capability of microrobots with the unique characteristics of puffballs, thereby illustrating a versatile avenue for development of a new generation of microrobots for targeted drug delivery.

Effect of Interfacial Lubrication between Rubber and Metal on Reducing Mixer Chamber Wall Wear in Mixing Process.

This paper focused on adding a suitable lubrication effect at the interface between the rubber and mixer chamber wall on reducing the surface wear rate of the mixer chamber wall. In the research process, the contact model between the compound and internal mixer chamber wall was simplified to the pin-on-disc experimental model. The experimental results showed that the friction coefficient and the metal surface wear rate of the mixer chamber were reduced (by approximately 24%) by adding an appropriate amount of antifriction agent in the mixing process, while the comprehensive properties of the compound showed an improvement trend. By analyzing the surface elements of the rubber compound, the MoS2 with an anti-wear effect on the surface of the rubber compound can form a lubrication mechanism between the rubber, filler, and mixer chamber wall metal. Combined with the result of the comprehensive properties of rubber, which showed that although the appropriate amount of antifriction agent formed a lubrication protection mechanism between the rubber and the inner mixing chamber wall, the mechanism did not affect the friction behavior required for mixing. The study can effectively enhance the effective friction mixing and reduce the wear and power consumption of the mixing chamber caused by excess friction during the mixing process.

Mechanical Cardiac Support With an Implantable Direct Cardiac Compression Device: Proof of Concept

PurposeWe examined the hemodynamic effects of a new, implantable, direct cardiac assist device in an ovine heart failure model. DescriptionThe device, which encompasses both left and right ventricles, is inserted through the pericardial apex and self-expands to encompass the heart without suturing. The intact pericardium anchors the device in place. The device has 2 concentric chamber layers: an internal chamber layer filled with fluid to conform to the heart and an external chamber layer filled with air that provides external compression and negative pressure to aid relaxation. EvaluationThe device was implanted in 7 sheep with heart failure induced by microsphere embolization. Cardiac performance was assessed for 6 to 8 hours. The cardiac assist device provided cardiac systolic and diastolic assistance, as shown by pressure tracings of the left ventricle and aorta, pulmonary artery flow, and +dP/dt. Central venous pressure decreased during cardiac assistance. No anatomic damage was noted postmortem. ConclusionsSystolic and diastolic cardiac assistance can be achieved with this device that compresses and relaxes in synchrony with the native cardiac cycle.

Thermo-fluid dynamics modelling of steam electrolysis in fully-assembled tubular high-temperature proton-conducting cells

Electrolysis based on renewable energies offers a promising carbon-free solution for hydrogen generation and storage. The recent developments of proton ceramic electrolysis cells operating at intermediate temperatures bear promise of superior energy efficiency compared to oxide ion conducting electrolytes. Here, a proton ceramic Single Engineering Unit (SEU) design is optimized for steam electrolysis using a computational fluid dynamics (CFD) model implemented in a COMSOL Multiphysics software. The SEU is an all-in-one tubular cell arrangement that constitutes the smallest electrolysis unit and enables efficient, adaptable pressurized hydrogen generation. The parametrical modelling study is conducted for two adiabatic operation scenarios with distinct steam conversion rates and tested for multiple key parameters, namely internal and external chamber pressures and inlet stream temperature. The modelling results show that low steam conversions enable operation at higher current densities and that the thermoneutral voltage for a fixed steam conversion is highly sensitive to the process conditions and operation modes. The increment of the pressure of the generated hydrogen implies a reduced production rate at thermoneutral voltage, although it can be compensated with an enhanced steam pressure or a reduced inlet temperature. Additionally, the introduction of a porous medium as the SEU current collector in the steam chamber enhances heat transport within this chamber. The area specific resistance of the system determines the current density, enforcing an adaption of the area of the electrolyser to satisfy the target hydrogen production and energy efficiency. The resulting proposed SEU design and adapted operational parameters allow effective delivery of pressurized dry hydrogen for a wide range of conditions and applications.

CAM-Delam Assay to Score Metastatic Properties by Quantifying Delamination and Invasion Capacity of Cancer Cells.

The major cause of cancer-related deaths is metastasis formation (i.e., when cancer cells spread from the primary tumor to distant organs and form secondary tumors). Delamination, defined as the degradation of the basal lamina and basement membrane, is the initial process that facilitates the transmigration and spread of cancer cells to other tissues and organs. Scoring the delamination capacity of cancer cells would indicate the metastatic potential of these cells. We have developed a standardized method, the ex ovo CAM-Delam assay, to visualize and quantify the ability of cancer cells to delaminate and invade, thereby being able to assess metastatic aggressiveness. Briefly, the CAM-Delam method includes seeding cancer cells in silicone rings on the chick chorioallantoic membrane (CAM) at embryonic day 10, followed by incubation from hours to a few days. The CAM-Delam assay includes the use of an internal humidified chamber during chick embryo incubation. This novel approach increased embryo survival from 10%-50% to 80%-90%, which resolved previous technical problems with low embryo survival rates in different CAM assays. Next, the CAM samples with associated cancer cell clusters were isolated, fixed, and frozen. Finally, cryostat-sectioned samples were visualized and analyzed for basement membrane damage and cancer cell invasion using immunohistochemistry. By evaluating various known metastatic and non-metastatic cancer cell lines designed to express green fluorescent protein (GFP), the CAM-Delam quantitative results showed that the delamination capacity patterns reflect metastatic aggressiveness and can be scored into four categories. Future use of this assay, apart from quantifying delamination capacity as an indication of metastatic aggressiveness, is to unravel the molecular mechanisms that control delamination, invasion, the formation of micrometastases, and changes in the tumor microenvironment.

CAM-Delam Assay to Score Metastatic Properties by Quantifying Delamination and Invasion Capacity of Cancer Cells

The major cause of cancer-related deaths is metastasis formation (i.e., when cancer cells spread from the primary tumor to distant organs and form secondary tumors). Delamination, defined as the degradation of the basal lamina and basement membrane, is the initial process that facilitates the transmigration and spread of cancer cells to other tissues and organs. Scoring the delamination capacity of cancer cells would indicate the metastatic potential of these cells. We have developed a standardized method, the ex ovo CAM-Delam assay, to visualize and quantify the ability of cancer cells to delaminate and invade, thereby being able to assess metastatic aggressiveness. Briefly, the CAM-Delam method includes seeding cancer cells in silicone rings on the chick chorioallantoic membrane (CAM) at embryonic day 10, followed by incubation from hours to a few days. The CAM-Delam assay includes the use of an internal humidified chamber during chick embryo incubation. This novel approach increased embryo survival from 10%-50% to 80%-90%, which resolved previous technical problems with low embryo survival rates in different CAM assays. Next, the CAM samples with associated cancer cell clusters were isolated, fixed, and frozen. Finally, cryostat-sectioned samples were visualized and analyzed for basement membrane damage and cancer cell invasion using immunohistochemistry. By evaluating various known metastatic and non-metastatic cancer cell lines designed to express green fluorescent protein (GFP), the CAM-Delam quantitative results showed that the delamination capacity patterns reflect metastatic aggressiveness and can be scored into four categories. Future use of this assay, apart from quantifying delamination capacity as an indication of metastatic aggressiveness, is to unravel the molecular mechanisms that control delamination, invasion, the formation of micrometastases, and changes in the tumor microenvironment.

The Development Study of a Prototype of Sodium Carboxymethylcellulose and Poly(Vinyl Alcohol) Wound Dressings Using a Mixer Torque Rheometer

The search for new materials that serve as dressings and promote the proper means for wound healing, without yielding toxic waste to the wound bed and at low cost, is currently the subject of research. In this sense, the present study aimed to develop a prototype of a poly(vinyl alcohol) (PVA) polymeric film, sodium carboxymethylcellulose (NaCMC). PVA and NaCMC as miscible polymer blend films for wound dressings was developed using internal mixing chamber processing in a mix torque rheometer (MTR) without the use of binders or crosslinks in different mixing conditions that were investigated by thermal characteristics (differential scanning calorimetry (DSC)) and thermogravimetric analysis (TGA) and crystallinity (X-ray Diffraction Technique (XRD)). The films obtained by pouring from this starting material were characterized by DSC, TGA, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), optical microscopy and swelling assay. All stages of development of this prototype are discussed, from the quality control of the raw materials, through the development of the preparation technique of the blends in 14 different processing conditions. The processed PVA/NaCMC film showed physical crosslinking which may have promoted its ability to resist dissolution in water (unprocessed PVA/NaCMC films’ characteristic). The results demonstrated that the processing of the PVA and NaCMC polymers in the MTR constitutes a viable technique to obtain membranes for use as dressings.

A High Performance Pneumatically Actuated Soft Gripper Based on Layer Jamming

Abstract This article presents a novel soft robotic gripper with a high payload capacity based on the layer jamming technology. Soft robots have a high adaptability, however suffer a low payload capacity. To overcome these conflicting challenges, here we introduce a 3D printed multi-material gripper that integrates jamming layers for enhancing payload capacity. By inflating the internal air chamber with positive pressure, the finger can be actuated to a large bending angle for adapting complex shapes. Layers of jamming sheets are bounded on the finger structure and are then sealed inside a vacuum bag. When a high payload is desired, air inside the vacuum bag is drawn out and a negative air pressure is applied to the jamming layers, which leads to the gripper locked at the actuated shape. To evaluate the performance of the gripper, we conducted extensive tests including actuation, stiffness variation, typical payload capacity, and adaptability. The results show that our gripper is not only highly adaptable just like most soft grippers but also more importantly capable of grasping heavy (about 6–10 kg) objects comparable to rigid-body counterparts.

Root-TRAPR: a modular plant growth device to visualize root development and monitor growth parameters, as applied to an elicitor response of Cannabis sativa

BackgroundPlant growth devices, for example, rhizoponics, rhizoboxes, and ecosystem fabrication (EcoFAB), have been developed to facilitate studies of plant root morphology and plant-microbe interactions in controlled laboratory settings. However, several of these designs are suitable only for studying small model plants such as Arabidopsis thaliana and Brachypodium distachyon and therefore require modification to be extended to larger plant species like crop plants. In addition, specific tools and technical skills needed for fabricating these devices may not be available to researchers. Hence, this study aimed to establish an alternative protocol to generate a larger, modular and reusable plant growth device based on different available resources.ResultsRoot-TRAPR (Root-Transparent, Reusable, Affordable three-dimensional Printed Rhizo-hydroponic) system was successfully developed. It consists of two main parts, an internal root growth chamber and an external structural frame. The internal root growth chamber comprises a polydimethylsiloxane (PDMS) gasket, microscope slide and acrylic sheet, while the external frame is printed from a three-dimensional (3D) printer and secured with nylon screws. To test the efficiency and applicability of the system, industrial hemp (Cannabis sativa) was grown with or without exposure to chitosan, a well-known plant elicitor used for stimulating plant defense. Plant root morphology was detected in the system, and plant tissues were easily collected and processed to examine plant biological responses. Upon chitosan treatment, chitinase and peroxidase activities increased in root tissues (1.7- and 2.3-fold, respectively) and exudates (7.2- and 21.6-fold, respectively). In addition, root to shoot ratio of phytohormone contents were increased in response to chitosan. Within 2 weeks of observation, hemp plants exhibited dwarf growth in the Root-TRAPR system, easing plant handling and allowing increased replication under limited growing space.ConclusionThe Root-TRAPR system facilitates the exploration of root morphology and root exudate of C. sativa under controlled conditions and at a smaller scale. The device is easy to fabricate and applicable for investigating plant responses toward elicitor challenge. In addition, this fabrication protocol is adaptable to study other plants and can be applied to investigate plant physiology in different biological contexts, such as plant responses against biotic and abiotic stresses.

Clay 3D printing as a bio-design research tool: development of photosynthetic living building components

Within architecture, microalgae are employed to address sustainability issues and mitigate the impacts of anthropogenic carbon dioxide (CO2) emissions. This study proposes digital fabrication of ceramic ‘living’ building components as an investigative tool for design conditions. The health of the chlorophyte (green) microalga Chlorella vulgaris was monitored over two-week periods when immobilized in kappa carrageenan and clay binder-based hydrogels, and grown on a range of digitally fabricated ceramic components. The use of 3D printing is presented in relation to laboratory testing of controlled substrate variables including the impact of ceramic firing temperature, component wall thickness, three types of geometry for exploring cell growth, surface patterns to investigate cell migration, internal chamber subdivisions and clay type. The experiments reveal the benefits and limitations of creating micro-ecologies for algae growth through the introduction of geometry variation. In this study, the natural organismal sensing abilities are explored as a means for cell distribution.

Energy efficient bioelectro-concentration and recovery system of nutrients from human urine by integrating forward osmosis

Human urine contains abundant nutrients, while separately collecting urine can significantly alleviate nutrient loads in existing wastewater treatment facilities. Herein,0020a novel forward osmosis integrated bioelectro-concentration and recovery system (OsBCRS) was developed to recover nutrient ions from urine. NH4+ and PO43– migrated out from urine and enriched in the internal chamber of OsBCRS driven by the self-generated electric field, which were further concentrated by water extraction from the integrated forward osmosis (FO) process, and finally recovered as struvite. The current density of OsBCRS reached 27.3 A m–3, which in turn drove the migration of NH4+-N (93.7 ± 1.6%) and PO43–-P (94.6 ± 0.8%) out from urine, and these separated nutrients were enriched by 9.4–9.5 times in the internal chambers. Subsequently, these enriched nutrients in the catholyte were 3.2-fold concentrated with 68.6% of volume reduction by FO. The system removed up to 83.4% of NH4+-N and 88.8% of PO43–-P, most of which were recovered as struvite taking advantage of reverse-fluxed Mg2+. The recovered struvite exhibited similar crystal structure and composition to that of standard struvite. The preliminary operating cost analysis of OsBCRS demonstrated that the revenue, including electricity generation and struvite recovery, could offset the operating cost. This study demonstrated highly efficient enrichment and recovery of nutrient ions from human urine by OsBCRS in a cost-effective way, and would encourage further exploration for nutrients recovery from wastes.

Five-axis Ultrasonic Thickness Measurement of Hollow Blade Wall and Evaluation of Internal Chamber Section

Hollow blades play an important role in the aircraft engines. To ensure the manufacturing quality of the hollow blades, an ultrasonic inspection method for inspecting the internal chamber is proposed in this paper. The measured data is obtained by a five-axis Coordinate Measuring Machine with an ultrasonic probe. To fill the vacancy of data in high-curvature regions, an approximation curve is constructed according to the theoretical section line and the measured points. By adjusting the position of the theoretical clamber point and setting the adjustment direction, the non-uniform shrinkage of the ceramic core is simulated and the calculation amount is reduced. Filling points are obtained from the approximation curve and the internal chamber section is reconstructed by these points. The internal chamber of the hollow blade is evaluated from the two aspects of line profile and wall thickness. The experiments have verified the effectiveness of the proposed method.

Ocular Biometric Values and Prevalence of Corneal Astigmatism in Patients Candidate for Cataract Surgery.

Purpose:To analyze the biometric values and the prevalence of corneal astigmatism in cataract surgery candidates.Methods:This is a prospective study. Ocular biometric values and corneal keratometric astigmatism were measured by optical low-coherence reflectometry (Lenstar LS 900) before surgery in patients who were candidates for cataract extraction surgery. Descriptive measurements of biometric dimensions and keratometric cylinder data and their correlations with sex and age were evaluated.Results:Ocular biometric and keratometric values from 2084 eyes of 2084 patients (mean age 66.43, range 19–95 years) were analyzed. The mean values were as follows: corneal astigmatism 0.89 diopter (D), mean corneal keratometry 44.29 D, central corneal thickness 534 μ, internal anterior chamber depth (ACD) 3.11 mm, lens thickness 4.50 mm, and axial length 23.35 mm. Corneal astigmatism was <1.25 D in 1660 (79.5%) of eyes. Astigmatism was with-the-rule in 976 (46.8%) of eyes, against-the-rule (ATR) in 702 (33.7%), and oblique in 406 (19.5%). Analysis of corneal astigmatism revealed a change toward “ATR” with age which was not statistically significant. The ACD was correlated with age. The amount of corneal astigmatism had no correlation with age and sex.Conclusion:Corneal astigmatism was higher than 1.25 D in about 21% of cataract surgery candidates with slight differences between the various age ranges and had no correlation with age and sex.

Economic Design, Fabrication, and Performance Evaluation of Conventional Ovens Made of Glass-Fiber-Reinforced Thermoset Composites

This study focuses on the development of a conventional oven using glass-fiber-reinforced thermoset composite sandwich panels. The design process considers the thermomechanical properties of the selected materials. The constructed rectangular box oven has the overall dimensions of 450 mm × 450 mm × 600 mm and internal heat chamber dimensions of 400 mm width, 400 mm depth, and 400 mm height with two stack trays for product placement. The sidewalls consist of inner and outer E-glass-fiber-reinforced composite panels with a sandwiched rockwool insulator. The bottom panel of the oven has an inner ceramic tile plate to suspend the electric heating element. The top panel is made of the same composite sandwich with a constructed superstructure electrical wiring compartment included for the controls. The oven can stably achieve a temperature of 150 ℃ and a cooking efficiency of approximately 39% when in operation and can sustain heat for more than 6 h standing time when turned off. The oven can be used for both culinary and laboratory experiments, i.e., heating, baking, drying, and curing materials, and is more affordable than alternative designs in the market.

A New Method for Correcting Deviation of Volatiles Content and Chamber Pressure for Single Base Propellant

In this study, special treatment was applied to two production batches of single-base propellant to correct three of the most important properties in the final product. These properties are internal and external volatile content (IV%, EV% respectively) and chamber pressure, the special treatments depend on mixing two batches with different percentages of mixing starting with sieving and ended with blending to guarantee the homogeneity of the final batch. The batches under study (A and B), batch A with (IV% 0.53%) which must be not less than 0.6%, so it deviated from standard requirement and Bach B with (IV =0.88%), the treatment applied for these batches to generate (C and D) batches. Batch C was a mixture composed of (25% of batch A and 0.75% of batch B). batch D was a mixture composed of (50%batchA and 50% of batch B). Six samples were subjected to sieving and blending according to calculations to correct internal and external volatile content and chamber pressure. For all samples lab, ballistics test, and executive calculations were done. After the test observed that no significant difference between the test and the results of calculations for all samples with different mixing ratios either volatiles content or chamber pressure so according to the result achieved the procedure (Method) was dependable for correcting the deviation of volatiles content and chamber pressure. The selectivity of the optimum mixing ratio can be controlled by using the equation used in this study. The importance of this study in reducing material losses due to the non-conformity of the final product with the specification.

A conceptual review of sustainable electrical power generation from biogas

AbstractHigh‐energy demand with rapid industrialization and mechanization combined with environmental pollution due to the burning of fossil fuels has driven a shift toward renewable energy. Biogas derived from biomass is a potential renewable energy source that can be used in different sectors such as transportation sector, electricity generation, heat production, combined heat and power (CHP) systems, and fuel cells. Moreover, the upgraded biogas can be applied as transportation fuel via an internal combustion chamber (for internal combustion engine (ICE) vehicles), and electricity station (for electric vehicles). In the present work, a conceptual review of biogas‐based electrical power production systems is presented. It is clear that the conventional types of biomass contain a high amount of pollutants and unwanted constituents, which lower the lower heating value (LHV) of biogas fuel. Moreover, the energy and exergy efficiencies of biogas applications are influenced by these components. Consequently, several biogas‐upgrading technologies have been elaborated to increase the LHV of biogas fuel by removing biogas pollutants. So, the energy and exergy analyses of biogas‐driven plants are discussed in this regard. Also, the economic analysis of biogas‐fueled systems is measured through the connection between biogas production, purchased electrical power, and selling of an additional amount of biogas. Biogas represents an important source of renewable energy as shown before, and it helps in waste management and W‐to‐E (waste to energy) conversion, which allows utilizing huge amounts of wastes instead of disposal or landfill procedures. However, handling of biogas from production to utilization has an impact on the environment. Therefore, the assessment of the environmental impacts of biogas plants is presented. In addition, a combination of the biogas energy with other sources, especially renewable energy sources (eg, solar‐biogas, geothermal‐biogas, wind‐biogas, CHP, CCHP, and concentrated photovoltaic‐biogas), and reusing waste energy for other tasks (eg, employing the waste heat from a gas turbine) are examined.

Operation of vibration source of an unbalance type with liquid-filled internal working chamber

Equipment for increasing water inflow to the well is proposed, which affects the aquifer by seismic vibrations. The method is based on accelerating the filtration process in soils, exposed to vibration. The equipment can work in conjunction with a submersible pump and has the ability to pump liquid through the working chamber of the generator. Generators can be combined into a group and driven by one electric motor to increase the efficiency of vibration treatment. This method is built into the existing technology of dewatering and pits drainage. The dynamics of the vibration source operation of an unbalance type with a liquid-filled inner chamber was studied in laboratory conditions, on a test. The vibration source was attached to the stand frame and was in a vertical position coaxially with the electric drive, thereby simulating its location in the well. The unbalance was unwound by an electric drive with a rotation frequency of 10 to 50 Hz in 5 Hz steps and seismic vibrations, generated by a vibration source, were recorded. Based on the experiments’ results, the amplitude-frequency characteristics of an unbalanced vibration source in the low-frequency range with a dry and liquid-filled inner chamber were obtained. In order to prevent the bearing assemblies from jamming, their heating was monitored with a thermal imager and temperature sensors.

Auswirkungen auf den vorderen Augenabschnitt beim Andocken eines Femtosekundenlasers an das Patienteninterface

Purpose. To compare the intraoperative OCT (optical coherence tomographer) of the femtosecond laser LenSx (Alcon Pharma GmbH, Freiburg) with a Scheimpflug-tomographer and an anterior segment OCT and thus to investigate a possible influence on the anterior segment of the eye when docking the patient’s interface. Material and Methods. A prospective cross-sectional study was conducted with 57 subjects who underwent a planned femtosecond laser-assisted cataract surgery or refractive lens exchange. The eye to be operated on was measured prior to the operation in mydriasis with the Visante OCT (Carl Zeiss Meditec AG, Jena) and the Pentacam AXL (Oculus Optikgeräte GmbH, Wetzlar). During the surgery, images of the anterior segment of the eye were taken by the integrated intraoperative OCT of the laser, which were evaluated afterwards and compared to the values of the other devices. The parameters examined were the internal anterior chamber depth (ACD), nasal and temporal chamber angles, central corneal thickness (CCT) and central lens thickness (LT). Results. The comparison of the intraoperative OCT and the two other devices showed clinically relevant differences in all parameters. The intraoperative OCT showed a 9.19 ± 27.55 μm larger CCT, 0.96 mm (median difference) larger LT, 0.05 mm smaller ACD than the Pentacam AXL and a 21.36 ± 25.50 μm larger CCT, 0.10 mm (median difference) smaller ACD than the Visante OCT. Conclusion. The comparison of the intraoperative OCT with the Visante OCT and the Pentacam AXL shows clinically relevant differences. Changes in the anterior segment of the eye may be due to errors in measurement or docking of the patient’s interface. Keywords. femtosecond laser, OCT, anterior segment of the eye, cataract surgery, refractive lens exchange

Experimental studies into the effect of air pressure on the atomization characteristics of coal-water slurries

The paper studies the effect of atomizing agent pressure on the spray characteristics after spraying coal-water slurry that contains small additives of liquid waste from the pyrolysis of industrial rubber goods and used engine oil. The conducted experiments used automobile tires as the indicated rubber products; spraying was carried out employing an internal mixing pneumatic atomizer. Following the atomization of considered fuels, droplet size changes were studied using the interferometric particle imaging (IPI) technique. The spray angle was determined by means of a Photron high-speed camera. In addition, coal-water slurry containing liquid waste from the pyrolysis of industrial rubber goods and used engine oil (3–12 wt%) was sprayed to study the effect of atomizing agent pressure on the spray characteristics. A decrease in air pressure was found to reduce the spray angle by less than 6%, which resulted in the formation of rather large droplets exceeding 600 µm in size. It is experimentally confirmed that more fine droplets are formed at similar fuel and air pressures when using a spraying device equipped with an internal mixing chamber for slurry and air. The number of droplets, in this case, is 2–9% higher as compared to a typical two-component coal-water slurry fuel, with the spray angle of the sprayed coal slurry having the greatest value. When using an atomizer having an internal mixing chamber for slurry and an atomizing agent, fuel droplet breakup occurs due to the aerodynamic drag forces of the environment. Thus, the use of such atomizers reduces the number of possible breakup mechanisms for sprayed fuel droplets.

Experimental study of the potential use of an expander for atmospheric freeze-drying

Atmospheric freeze-drying (AFD) is a promising technique that is increasingly popular in drying applications. In this study, a novel method to generate the cold and dry air suitable for AFD applications using an expander is proposed. The concept is simple, able to simultaneously cool and dehumidify air, control the discharged air pressure, and provides the potential for energy saving. An idealized theoretical model to simulate the process was developed. Experiments were conducted at various pressure and speed conditions. The study shows that the expander's maximum volumetric and isentropic efficiencies were 27.2% and 21.8%, respectively. Observation of the internal chamber pressures was able to explain the relatively low isentropic efficiency. The maximum power output and expander efficiency were 56 W and 42.7%, respectively. The expander was able to cool the air to below 0 °C, and the lowest measured outlet air temperature was −8.7 °C. The outlet air relative humidity was between 3.6% to 4.7%. The measured dehumidification effectiveness was between 79.8% to 93.1%. The study shows that the concept is promising, and the expander was able to generate the required air conditions suitable for AFD applications.