Programmable Temperature Controller Research Articles

Programmed temperature control for inactivation of Clostridium perfringens spores in cooked chicken with different germinants

This study designed a new programmed temperature control (PTC) process for cooked chicken, aiming to increase the efficacy of Clostridium perfringens spore inactivation through inducing spore germination at different levels of dormancy. The results showed that the use of PTC treatment in the presence of germinant AGFK (a mixture of l-asparagine, D-glucose, D-fructose, and KCl) lead to a reduction of exceeding 6 lg CFU/mL spores in a model system after being subjected to 90 °C for 20 min. A significant up-regulation of gerKA, gerKC and gerAA relative expression suggested that the PTC treatment may induce more spore germination. Meanwhile, there was an observed rise in the release of pyridine-2,6-dicarboxylic acid, accompanied by a steady decline in refractivity. In the cooked chicken meat undergone a cooling process, the number of C. perfringens spores were reduced by approximately 5 lg CFU/g after the PTC treatment and heated at 90 °C for 20 min. In conclusion, the PTC treatment can effectively enhance the inactivation of C. perfringens spores by inducing more spore germination at different levels of dormancy during cooked meat preparation.

Design of a High Precision Multichannel 3D Bioprinter

Three-dimensional (3D) printing technology is expected to solve the organ shortage problem. However, owing to the accuracy limitations, it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet. In this study, to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs, a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed, and concurrent and synergistic printing methods are proposed. Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing, a 3D bioprinting system with a set of 6 channels is designed to achieve six-in-one printing. Based on the Visual C++ environment, a control system software that integrates the programmable multi-axis controller (PMAC) motion, pneumatic, and temperature control subsystems was developed and designed. Finally, based on measurements and experiments, the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel, concurrent, and synergistic printing with submicron-level motion accuracy, significantly shortening the printing time and improving the printing efficiency. This study not only provides an equipment basis for printing complex heterogeneous tissue structures, but also improves the flexibility and functionality of bioprinting, and ultimately makes the construction of complex multicellular tissues or organs possible.

3D Printed Photothermal Scaffold Sandwiching Bacteria Inside and Outside Improves The Infected Microenvironment and Repairs Bone Defects.

Bone infection is one of the most devastating orthopedic outcomes, and overuse of antibiotics may cause drug-resistance problems. Photothermal therapy(PTT) is a promising antibiotic-free strategy for treating infected bone defects. Considering the damage to normal tissues and cells caused by high-temperature conditions in PTT, this study combines the antibacterial property of Cu to construct a multi-functional Cu2 O@MXene/alpha-tricalcium phosphate (α-TCP)scaffold support with internal and external sandwiching through 3D printing technology. On the "outside", the excellent photothermal property of Ti3 C2 MXene is used to carry out the programmed temperature control by the active regulation of 808nm near-infrared (NIR) light. On the "inside", endogenous Cu ions gradually release and the release accumulates within the safe dose range. Specifically, programmed temperature control includes brief PTT to rapidly kill early bacteria and periodic low photothermal stimulation to promote bone tissue growth, which reduces damage to healthy cells and tissues. Meanwhile, Cu ions are gradually released from the scaffold over a long period of time, strengthening the antibacterial effect of early PTT, and promoting angiogenesis to improve the repair effect. PTT combined with Cu can deliver a new idea forinfected bone defects through in vitro and vivo application.

Selection of iron-based oxygen carriers for two-step solar thermochemical splitting of carbon dioxide

The two-step solar thermochemical cycle is a prospective clean energy technology that enables the direct splitting of water and carbon dioxide for solar fuel production. However, immature oxygen carriers fundamentally restrict the solar-to-fuel conversion efficiency and thus prevent this technology from immediate industrial uptake. Focusing on the conventional iron-based oxygen carriers, this study intends to find a modified oxygen carrier with low reaction temperature requirements and excellent reaction performance, so as to attain dual optimization in terms of thermal efficiency and chemical efficiency. The thermochemical reaction characteristics of six common ferrites and four metal dopants are compared via thermogravimetric analysis under the same programmed temperature control. For further practical applications of the selected oxygen carrier, a foam-structured material with SiC as support is prepared and subsequently experimented in a self-designed 18-kW thermochemical system. The results indicate that the modified oxygen carriers obtained by direct doping of CoFe2O4 with 50wt% NiO exhibit optimal reaction performance, giving the highest CO yield of 439μmol/g. Additionally, the foam-structured material enable a peak CO yield of 7.0 mL min−1 g−1 and CO2 conversion of 45.5% at a reduction temperature of only 1100°C, which might be attributed to the micron-scale pore structure as well as the generation of aluminosilicate crystal structures.

Effect of Cow Dung to Maize Silage Mix Ratios and Temperature Variation on Biogas Production in Laboratory Batch Digester

Optimization of biogas production from a given substrate and digester is an issue that needs to be addressed during the development of anaerobic digestion. To maximize the biogas production rate, the operating parameters that influence anaerobic digestion must be controlled and monitored. This research was carried out using a 0.15 m³ laboratory digester. The study evaluated the effect of cow dung and maize silage mix ratios (1:1, 1:3, and 3:1) on biogas production which were compared to their pure substrates at a constant temperature of 20°C. The temperatures (20°C, 25°C, and 30°C) were then evaluated using the optimal mix ratio of 3:1 as feedstock. The Temperature of the digester was controlled and monitored using Programmable Temperature Controller (Multispan UTC 421) and the (PLC) running on SIEMENS LOGO. The mix ratios and temperatures showed a significant effect on biogas production (P≤0.05) with mix ratios of 3:1 and 1:1 improving biogas production by 31.24% and 15.52% respectively compared to cow dung. The temperatures of 25°C and 30°C increased biogas by 26.99% and 47.35% and methane increased by 3.92% and 11.76% respectively compared to the mesophilic temperature of 20°C. The study thus, recommends a mix ratio of 3:1 and the optimal temperature of 30°C for a 0.15 m³ laboratory temperature-controlled fixed-dome anaerobic digester of cow dung and maize silage as a substrate when fed as a batch reactor.

Dynamic characteristics of the railway ballast bed under water-rich and low-temperature environments

Studying the dynamic characteristics and evolution laws of the ballast bed under low-temperature, rain and snow environments has practical significance for the driving stability of railways in alpine. In this paper, a full-scale ballasted track model was constructed in a programmable temperature control laboratory, and the frequency response function (FRF) curves of the ballast bed under different temperature and humidity conditions were measured. Then the vibration characteristics and the evolution laws of the ballast bed under different conditions were analyzed. The longitudinal transfer behavior and the dissipation of the vibration energy in the ballast bed under different humidity and temperature environments were discussed combined with the finite element method. The results show that the influence of temperature on the vibration characteristics of the ballast bed is not significant in the dry and water-rich environments, but the vibration characteristics of the ballast bed in the frozen environment change dramatically with the decrease of temperature. The vibration energy is harder to dissipate in the frozen ballast bed than in the dry and water-rich ballast beds, and the frozen ballast bed is more prone to be sudden damaged when a train passes due to the significant increase in its stiffness. Thus, the performance monitoring and emergency maintenance of the ballast bed in those environments should be strengthened.

An inexpensive, versatile, compact, programmable temperature controller and thermocycler for simultaneous analysis and visualization within a microscope

An inexpensive, versatile, compact, programmable temperature controller and thermocycler for simultaneous analysis and visualization within a microscope

An inexpensive, versatile, compact, programmable temperature controller and thermocycler for simultaneous analysis and visualization within a microscope

Microfluidic Lab on a Chip (LOC) devices are key enabling technologies for research and industry due to their compact size, which increases the number of integrated operations while decreasing reagent use. Common operations within these devices such as chemical and biological reactions, cell growth, or kinetic measurements often require temperature control. Commercial temperature controllers are constrained by cost, complexity, size, and especially versatility for use in a broad range of applications. Small companies and research groups need temperature control systems that are more accessible, which have a wide applicability. This work describes the fabrication and validation of an inexpensive, modular, compact, and user-friendly temperature control system that functions within a microscope. This system provides precise temperature acquisition and control during imaging of any arbitrary sample which complies with the size of a microscope slide. The system includes two parts. The first part is a compact and washable Device Holder that is fabricated from high-temperature resistant material and can fit securely inside a microscope stage. The second part is a robust Control Device that incorporates all the necessary components to program the temperature settings on the device and to output temperature data. The system can achieve heating and cooling times between 50 °C and 100 °C of 32 s and 101 s, respectively. A Bluetooth enabled smartphone application has been developed for real-time data visualization. The utility of the temperature control system was shown by monitoring rhodamine B fluorescence in a microfluidic device over a range of temperatures, and by performing a polymerase chain reaction (PCR) within a microscope. This temperature control system could potentially impact a broad scope of applications that require simultaneous imaging and temperature control.

Using Flight Mills to Measure Flight Propensity and Performance of Western Corn Rootworm, Diabrotica virgifera virgifera (LeConte).

The western corn rootworm, Diabrotica virgifera virgifera (LeConte) (Coleoptera: Chrysomelidae), is an economically important pest of corn in the northern United States. Some populations have developed resistance to management strategies including transgenic corn that produces insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Knowledge of western corn rootworm dispersal is of critical importance for models of resistance evolution, spread, and mitigation. Flight behavior of an insect, especially over a long distance, is inherently difficult to observe and characterize. Flight mills provide a means to directly test developmental and physiological impacts and consequences of flight in the laboratory that cannot be obtained in field studies. In this study, flight mills were used to measure the timing of flight activity, total number of flights, and the distance, duration, and speed of flights taken by female rootworms during a 22-h test period. Sixteen flight mills were housed in an environmental chamber with programmable lighting, temperature, and humidity control. The flight mill described is of a typical design, where a flight arm is free to rotate about a central pivot. Rotation is caused by flight of an insect tethered to one end of the flight arm, and each rotation is recorded by a sensor with a time-stamp. Raw data are compiled by software, which are subsequently processed to provide summary statistics for flight parameters of interest. The most difficult task for any flight mill study is attachment of the tether to the insect with an adhesive, and the method used must be tailored to each species. The attachment must be strong enough to hold the insect in a rigid orientation and to prevent detachment during movement, while not interfering with natural wing motion during flight. The attachment process requires dexterity, finesse, and speed, making video footage of the process for rootworms of value.

Energy performance of five different building envelope structures using a modified Guarded Hot Box apparatus—Comparative analysis

The most of thermal characteristics of buildings are currently calculated by simplified mathematical models of building envelope behaviour. The main parameter needed for these calculations is the thermal transmittance. The aim of this study is to evaluate thermal performance of several building envelopes suitable for thermal insulating purposes and to compare parameters of thermal performance given by national standards or the thermal performance declared by producers. The experimental measurements were conducted with dynamic conditions in the cold chamber of the Hot Box. Dynamic testing was running under weekly temperature cycle using programmable temperature controller in the cold chamber. Hot site temperature was kept steady according to controlled ambient temperature. Behaviour of each system was investigated under similar conditions with room temperature 22–23 °C in the hot chamber and with temperature fluctuation between +6 °C and −13 °C in the cold chamber. This study provides interesting results. Especially heat flow in case of laminated log wall (massive wood) of thickness 200 mm was measured as significantly lower than it would be calculated by currently known thermal conductivity of soft wood. The presented method of thermal transmittance measurements in dynamic conditions might bring increasing accuracy for building envelope energy loss calculations. The difference between result from one-week long test compared with 20 days long test of the same sample was found as 2,3%. Correlation coefficient between experimental values and calculated total energy loss in time was always found higher than 0,997 and accuracy seems to be increasing with length of the measurement.

Experimental studies on cycling stable characteristics of inorganic phase change material CaCl2·6H2O-MgCl2·6H2O modified with SrCl2·6H2O and CMC

By means of mass ratio method, binary eutectic hydrated salts inorganic phase change thermal energy storage system CaCl2·6H2O-20wt% MgCl2·6H2O was prepared, and through adding nucleating agent 1wt% SrCl2·6H2O and thickening agent 0.5wt% carboxy methyl cellulose (CMC), inoganic phase change material (PCM) modified was obtained. With recording cooling-melting curves simultaneously, this PCM was frozen and melted for 100 cycles under programmable temperature control. After per 10 cycles, the PCM was charaterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and density meter, then analysing variation characteristics of phase change temperature, supercooling degree, superheat degree, latent heat, crystal structure and density with the increase of cycle index. The results showed that the average values of average phase change temperature for cooling and heating process were 25.70°C and 27.39°C respectively with small changes. The average values of average supercooling and superheat degree were 0.59°C and 0.49°C respectively, and the maximum value was 1.10°C. The average value and standard deviation of latent heat of fusion were 120.62 J/g and 1.90 J/g respectively. Non-molten white solid sediments resulted from phase separation were tachyhydrite (CaMg2Cl6·12H2O), which was characterized by XRD. Measuring density of the PCM after per 10 cycles, and the results suggested that the total mass of tachyhydrite was limited. In summary, such modified inoganic PCM CaCl2·6H2O-20wt% MgCl2·6H2O-1wt% SrCl2·6H2O-0.5wt% CMC could stay excellent circulation stability within 100 cycles, and providing reference value in practical use.

Tuning Optical Activity of IV–VI Colloidal Quantum Dots in the Short-Wave Infrared (SWIR) Spectral Regime

The achievement of tunable optical properties across a wide spectral range, along with an efficient surface passivation of lead chalcogenide (PbSe) colloidal quantum dots (CQDs), has significant importance for scientific research and for technological applications. This paper describes two comprehensive pathways to tune optical activities of PbSe CQDs in the near-infrared (NIR, 0.75–1.4 μm) and the short-wave infrared (SWIR, 1.4–3 μm) ranges. A one-pot procedure enabled the growth of relatively large PbSe CQDs (with average sizes up to 14 nm) exploiting programmable temperature control during the growth process. These CQDs showed optical activity up to 3.2 μm. In addition, PbSe/PbS core/shell CQDs prepared by an orderly injection rate led to an energy red-shift of the absorption edge with the increase of the shell thickness, whereas a postannealing treatment further extended the band-edge energy toward the SWIR regime. A better chemical stability of the CQDs with respect to that of PbSe core CQDs was atta...

A Method for In-Situ, Total Ionising Dose Measurement of Temperature Coefficients of Semiconductor Device Parameters

This work presents and discusses a test method developed to allow the measurement of total ionising dose induced changes in temperature effects on electronic devices for space and nuclear applications. Two demonstration experiments testing commercial PMOS transistors were performed, using different methods of I-V curve measurement. The temperature of the devices during irradiation was controlled precisely using a commercial thermoelectric cooler. A programmable temperature controller combining digital and analogue control techniques was developed for this project. The experimental results allow better insight into the field of temperature sensitivity of PMOS devices.

Fabrication of heterogeneous nanomaterial array by programmable heating and chemical supply within microfluidic platform towards multiplexed gas sensing application.

A facile top-down/bottom-up hybrid nanofabrication process based on programmable temperature control and parallel chemical supply within microfluidic platform has been developed for the all liquid-phase synthesis of heterogeneous nanomaterial arrays. The synthesized materials and locations can be controlled by local heating with integrated microheaters and guided liquid chemical flow within microfluidic platform. As proofs-of-concept, we have demonstrated the synthesis of two types of nanomaterial arrays: (i) parallel array of TiO2 nanotubes, CuO nanospikes and ZnO nanowires, and (ii) parallel array of ZnO nanowire/CuO nanospike hybrid nanostructures, CuO nanospikes and ZnO nanowires. The laminar flow with negligible ionic diffusion between different precursor solutions as well as localized heating was verified by numerical calculation and experimental result of nanomaterial array synthesis. The devices made of heterogeneous nanomaterial array were utilized as a multiplexed sensor for toxic gases such as NO2 and CO. This method would be very useful for the facile fabrication of functional nanodevices based on highly integrated arrays of heterogeneous nanomaterials.

Experimental Study of Compliant Mechanism Considering Thermal Effect

In this paper, an ultra-precision positioning stage is introduced. The finite element method is used to establish the theoretical model, and the strain test system of experiment is established. The system includes the static strain test and the dynamic strain test. The test system contains the software and hardware system. The software system includes the static strain measurement software of DH3816, the programmable constant temperature and humidity chamber control software TEMI300, and the dynamic strain test system developed from NI Labview. The hardware system contains industrial personal computer (IPC), piezoelectric (PZT) actuator, static strain gauge of DH3816, strain amplifier of YE1817, NI USB-6009 multifunction data acquisition card, strain gauge, programmable temperature and humidity chamber, and precision positioning stage. The experimental test is carried out to examine the theoretical analysis considering thermal effect. Experimental results and analytical results indicate that whether the stresses increase or decrease linearly or nonlinearly depend on the function of the temperature to the time during the transient response same as the stresses increase or decrease linearly during the steady response under uniform temperature change. The dynamic responses of platform are affected by the temperature change, and it is essential to consider thermal effect when analyzing compliant mechanisms.

Design of Programmed Temperature Control Gas-Sensing Characteristic Tester

In order to reduce the complexity of the experiment processes for the study of gas-sensing material properties, we have designed programmed temperature control gas-sensing characteristic tester. To obtain the precise measurement of gas-sensing materials’ resistance and programmed output voltage, the tester has used ratio method, SCM control technology, basic circuit principles, A/D converter, D/A conversion, the feedback network. Test results show that this system provides a great convenience for gas-sensing materials testing.

Design of an AC Conductivity Measurement Setup for Sensor Materials Characterization

AC conductivity measurement can be an effective method for the study of sensor material characteristics for gas sensing. The authors have designed and fabricated a sensitive set up for sensor material characterization using ac conductivity measurement. The set up fabricated is employed for bulk samples. AC conductivity cell with cold fingertip that can facilitate measurement in the range 80 K to 500 K has been fabricated. The necessary vacuum lines and gas feed throughs are provided in order to study the gas sensing characteristics of semiconductor gas sensor materials. A programmable PID temperature controller and the necessary signal conditioning circuits are designed and incorporated into the system. AC conductivity measurement is carried out using Fluke PM 6306 impedance analyzer.

A Microfluidic Device for Preparing Next Generation DNA Sequencing Libraries and for Automating Other Laboratory Protocols That Require One or More Column Chromatography Steps

Library preparation for next-generation DNA sequencing (NGS) remains a key bottleneck in the sequencing process which can be relieved through improved automation and miniaturization. We describe a microfluidic device for automating laboratory protocols that require one or more column chromatography steps and demonstrate its utility for preparing Next Generation sequencing libraries for the Illumina and Ion Torrent platforms. Sixteen different libraries can be generated simultaneously with significantly reduced reagent cost and hands-on time compared to manual library preparation. Using an appropriate column matrix and buffers, size selection can be performed on-chip following end-repair, dA tailing, and linker ligation, so that the libraries eluted from the chip are ready for sequencing. The core architecture of the device ensures uniform, reproducible column packing without user supervision and accommodates multiple routine protocol steps in any sequence, such as reagent mixing and incubation; column packing, loading, washing, elution, and regeneration; capture of eluted material for use as a substrate in a later step of the protocol; and removal of one column matrix so that two or more column matrices with different functional properties can be used in the same protocol. The microfluidic device is mounted on a plastic carrier so that reagents and products can be aliquoted and recovered using standard pipettors and liquid handling robots. The carrier-mounted device is operated using a benchtop controller that seals and operates the device with programmable temperature control, eliminating any requirement for the user to manually attach tubing or connectors. In addition to NGS library preparation, the device and controller are suitable for automating other time-consuming and error-prone laboratory protocols requiring column chromatography steps, such as chromatin immunoprecipitation.

Automated Quantitative RNA in Situ Hybridization for Resolution of Equivocal and Heterogeneous ERBB2 (HER2) Status in Invasive Breast Carcinoma

Patient management based on HER2 status in breast carcinoma is an archetypical example of personalized medicine but remains hampered by equivocal testing and intratumoral heterogeneity. We developed a fully automated, quantitative, bright-field in situ hybridization technique (RNAscope), applied it to quantify single-cell HER2 mRNA levels in 132 invasive breast carcinomas, and compared the results with those by real-time quantitative PCR (qPCR) and Food and Drug Administration-approved methods, including fluorescence in situ hybridization (FISH), IHC, chromogenic in situ hybridization, and dual in situ hybridization. Both RNAscope and qPCR were 97.3% concordant with FISH in cases in which FISH results were unequivocal. RNAscope was superior to qPCR in cases with intratumoral heterogeneity or equivocal FISH results. This novel assay may enable ultimate HER2 status resolution as a reflex test for current testing algorithms. Quantitative in situ RNA measurement at the single-cell level may be broadly applicable in companion diagnostic applications.

Measurement of Spectral Emissivity near Room Temperature with a Vacuum Blackbody Using a Cryogenic Refrigerator

A new type of vacuum blackbody containing both a blackbody cavity and a solid material sample was fabricated using a cryogenic refrigerator. It was to construct a highly sensitive infrared spectral-radiation measurement system using a programmable temperature control device, a Fourier transform infrared spectrophotometer, and two mercury-cadmium-telluride (MCT) detectors. Evaluation showed that the temperature of the blackbody cavity wall was accurately set within ±0.2 K for 173 to 373 K and that the nonlinearity of the system response output at 173 to 373 K was within 0.8% with the proper use of the two MCT detectors. An emissivity comparison experiment using black paint (No. 1) showed that the proposed blackbody cavity method had a coincidence within 0.015 of a diffuse reflectance measuring method at 5 to 11.6 μm. For ceramics, the emissivity temperature dependence for alumina and zirconia at 273 to 373 K was within ±0.06 and ±0.04, respectively.