Control Chamber Research Articles

Profile of Producers and Production of Dry-Aged Beef in Brazil.

No information is currently available on the profile of producers and production process of dry-aged beef in Brazil, to the best of the authors’ knowledge. We surveyed 37 Brazilian companies that were producing dry-aged beef in 2020 to investigate this market. The absolute and relative frequency of responses was calculated to obtain the sum, average, minimum, and maximum values. From the respondents, dry-aged beef was first produced in 2009, and most producers are located in big cities. Most respondents control and monitor chamber temperature; however, humidity and air velocity only are monitored. The aging period (mostly between 22 to 60 days) was the main indicator of product readiness. The process losses (water loss and crust trimming) can reach 65%. Some producers perform microbiological analyses to ensure product safety and others use tools such as GMP and SOP. The results of this survey may help governmental institutions to develop a standardized industrial protocol for producing dry-aged beef in Brazil.

BIOLOGICAL TRAITS OF BEAN FLOWER THRIPS, Megalurothrips usitatus (THYSANOPTERA: THRIPIDAE) REARED ON MUNG BEAN

The bean flower thrips, Megalurothrips usitatus is a major pest of mung bean that causes flower dropping and significant yield loss of the crop. M. usitatus demonstrated to have variable lifespan when reared on different leguminous hosts but on mung bean, an important pulse crop in Bangladesh, is unknown. The experiment was conducted to determine the biological attributes of M. usitatus on mung bean in a climate control chamber at 26 ± 1°C, 75 ± 3% RH, and 16:8 hours L:D in the laboratory. The results revealed that the incubation period, first instar larva, second instar larva, prepupa, and pupal period of M. usitatus were 3.13 ± 0.06, 1.48 ± 0.05, 2.30 ± 0.08, 1.30 ± 0.07, and 2.26 ± 0.13 days, respectively. The combined developmental period from egg to adult was 10.54 ± 0.15 (mean ± SE) days. The larvae of M. usitatus were similar in appearance to the adults, but they lacked wings and were smaller and different in color. The first instar was pale yellow, while the second instar was darker and larger, ranging from deep yellow to orange-red. The wing pads of the prepupae were shorter than that of the pupae. The antennae of the prepupa were straight, but they were bent in the pupa. In the case of pre-adult mortality of M. usitatus, the mortality of the first instar larva was 14.41%, second instar larva 22.77%, prepupa 14.10%, and pupa 65.67%. The pre-adult mortality was 80.51% overall. Adult males had lower longevity (6.42 ± 0.44 days) than females (12.07± 1.56 days). The developmental period of M. usitatus on mung bean indicated the suitability of the leguminous crop as a potential host, as well as the need for information on the pest’s various growth stages in order to design effective management strategies.

Experimental investigations into the effects of string cavitation on diesel nozzle internal flow and near field spray dynamics under different injection control strategies

On the test bench of the high-pressure common rail injection system with a high-speed camera, the visualization experiments of real-size tapered hole nozzle of the diesel engine were performed to obtain needle valve lift, string cavitation in the sac chamber and nozzle hole, residual bubbles and near-field spray characteristic. And a high-pressure sensor was utilized to measure the real pressure fluctuation for the nozzle inlet. On the basis, under different control strategies, the comprehensive effects of needle valve throttling and pressure fluctuation for nozzle inlet on the internal flow and near-field spray characteristic under the multiple injections were studied. Research indicated that the spray cone angle and the spray area ratio in the main injection stage shows a boot-shaped increasing trend of slowness and then abruptness. In the development stage, the spray cone angle fluctuates in a little range (20°-30°); In the saturation phase, the spray cone angle fully develops and the fluctuation is relatively stable (40°-50°). As the throttling position shifts, there is an obvious string cavitation process, and the spray cone angle increases suddenly. In the process of pre-injection and post-injection, needle valve and valve seat throttling and lift instability cause fuel pressure fluctuation in the control chamber and sac, which is the main immediate cause of the fluctuation of low fuel injection quantity. Besides, the interval time between multiple injections, on the one hand, affects the state of residual bubbles in the nozzle before the next injection beginning, on the other hand, it also affects the stability of the inlet pressure at this time. The flow transition in the low-lift zone and the cavitation changing in the high-lift stable zone also cause transformation in the form of pressure fluctuation.

Oil yield components and biomass production responses to warming during the oil accumulation phase in young olive trees

Global warming and olive expansion to new regions have increased interest in understanding how air temperature affects olive production. Thus, the objective of this study was to evaluate the responses of oil yield components, total biomass production, and its partitioning to a moderate temperature increase (3–4 °C) during the oil accumulation phase in young olive trees of two olive cultivars (cvs. Arbequina, Coratina). Young, potted olive trees were actively heated by 3–4 °C in open top chambers under outdoor conditions compared to near-ambient temperature in similar control chambers. The trees were warmed from final fruit set to the end of the oil accumulation phase (5 months) in one (2014–15 or 2015–16) or in two consecutive seasons. Oil yield and its components were obtained from fruit harvested at the end of the season, while the vegetative dry biomass produced was estimated from destructive harvests of entire trees before and after a warming period. Glucose equivalents (GE) were also calculated for both oil yield and vegetative growth. Warming during the oil accumulation phase in one season led to some significant temperature x cultivar interactions for oil components. Individual fruit dry weight was reduced by warming to a greater extent in cv. Coratina than in cv. Arbequina, while fruit oil concentration was decreased more in cv. Arbequina. Significant decreases in oil yield were also observed for both cultivars. Warmed trees had a greater net leaf area increase than control trees when heated during the oil accumulation phase for one season (2014–15 or 2015–16), and allocated more GE to vegetative organs than to fruit in 2015–16. However, total tree biomass was not affected by warming. Warming trees the first season led to reduced flowering the following spring, and directly contributed to a temperature x cultivar interaction for fruit number during the second warming period with a 66% reduction in fruit number in warmed trees of cv. Arbequina and very low fruit number in all cv. Coratina trees. In contrast to warming during one season, total tree biomass GE decreased across cultivars when warming was performed in the oil accumulation phase for two consecutive seasons. The results suggest that cultivars should be carefully selected for new, warmer growing regions and that global warming may ultimately reduce oil yields and affect cultivar selection.

Influence of temperature and daily leaf wetness duration on the severity of bacterial leaf blight of garlic

ABSTRACT In the present study, climate control chamber conditions were adopted to investigate the influence of temperature (10, 15, 20, 25 and 30°C) and leaf wetness duration (6, 12, 24 and 48 hours) on the severity of bacterial leaf blight of garlic, caused by Pseudomonas marginalis pv. marginalis. The relative density of lesions was influenced by temperature and leaf wetness duration (P<0.05). The disease was more severe at 20°C. The obtained data underwent non-linear regression analysis. Generalized beta function was used to fit the data on severity and temperature, while a logistic function was chosen to represent the effect of leaf wetness duration on the severity of bacterial blight. The response surface resulting of the product of those two functions was expressed as ES = 0.019419 * (((x-5)0.5893) * ((35-x)0.5474)) * (0.51754/(1+23.59597* exp (-0.145695*y))), where: ES represents the estimated severity value (0.1); x, the temperature (ºC), and y, the daily leaf wetness duration (hours). This model shall be validated under field conditions to assess its use as a forecast system for bacterial leaf blight of garlic.

Responses of beef calves to long-term heat stress exposure by evaluating growth performance, physiological, blood and behavioral parameters.

The objective of this study was to explore the responses of beef calves to long-term heat stress (HS) exposure at various levels in comparison with the animals under thermoneutral conditions by evaluating growth performance, physiological, blood, and behavioural parameters. Data were collected from sixteen beef calves (BW: 136.9±6.23kg; age: 169.6±4.60d) kept at four stress levels of designated temperature humidity index (THI): threshold (22-24°C, 60%; THI=70 to 73), mild (26-28°C, 60%; THI=74 to 76), moderate (29-31°C, 80%; THI=81 to 83), and severe (32-34°C, 80%; THI=89 to 91) stress levels in climatic controlled chambers. Feed and water intake were recorded daily, and body weight was measured once a week. Blood was sampled every three days to analyse metabolite parameters. Dry matter intake (DMI) (p=0.069, tendency) and blood glucose levels (p=0.028) were decreased after sudden exposure to HS conditions (severe THI levels). Also, blood cortisol (p=0.002), glutamic-oxaloacetic transaminase (GOT) (p=0.009), blood urea nitrogen (BUN) (p=0.004) and standing time (p=0.009) were increased in moderate and severe THI levels compared with threshold after exposure to HS conditions. However, in the severe THI group, blood cortisol (p<0.05), glucose (p<0.05), GOT (p<0.05) and BUN (p<0.05) levels were returned to normal range after 6-13 days of continuous HS exposure. In conclusion, DMI, blood cortisol, GOT, glucose, BUN, and standing time were closely associated with long-term HS condition in beef calves. In addition, calves exposed to HS modulated their physiological responses that resulted in the regulation of the pertinent blood metabolites in the blood to maintain homeostasis during the long-term HS.

A novel low pressure-difference fluctuation electro-hydraulic large flowrate control valve for fuel flowrate control of aeroengine afterburner system

To address the control accuracy of large fuel flowrate during pressure fluctuation, a novel electro-hydraulic fuel metering unit (FMU) is constructed for afterburner fuel system of military aeroengine. Different from the previous FMU, the proposed FMU can achieve the higher precision opening control by a new metering valve with double control chambers (MVDCC), and realize the lower pressure difference fluctuation regulating by a novel two-stage constant pressure difference compensated valve (CPDCV) with dynamic damping orifice and damping piston. The experimental and AMESim simulation results verify the validity and superiority of the novel FMU. Since the temperature-induced variation in fuel properties and device capabilities may degrade or even impair the properties of novel FMU, the discharge flowrate is analyzed by global sensitivity analysis to research the effect proportion of each factor, the temperature effect is explored to ensure the working reliability in long-span temperature variation. Finally, the optimization of structure parameters for novel CPDCV can further reduce pressure difference fluctuation during pressure regulation, and the overshoot, adjust time and the integral of time multiplied by absolute value of error (ITAE) can be reduced by 24%, 30% and 26%, respectively. This paper provides a reference for improving the stability of large flowrate during pressure fluctuation.

Evaluation of foamed nickel photocatalytic filters for an air cleaner on removal of formaldehyde in the indoor environment

Foamed nickel photocatalytic filters based on zinc oxide and fitted to standard air cleaner are assessed under the same indoor air quality conditions in a real test site setting with UV light applied via a suitable lamp. Environmental parameters determined using a chamber test are input to the mass balance model and airflow analysis software (CONTAM) to simulate the change of HCHO concentration with time at the real test site. The mass balance model is validated by mean absolute percentage error (MAPE). Results of the environmental control chamber test for ZnO filters at 60 min interval show the highest removal efficiency for HCHO are under no UV light irradiation. It also shows that regardless of whether the UV lamp is on or off, the highest removal efficiency for HCHO is under high humidity and low concentration. The removal efficiency of HCHO with application of UV light is not significantly affected by low humidity and low concentration. Clean air delivery rates (CADR) of the air cleaner are consistent with HCHO removal efficiency, i.e., higher CADR brings higher removal efficiency. The results show the removal efficiency of HCHO by TiO2 photocatalytic filters is higher than that obtained with ZnO photocatalytic filters under UV light irradiation. For the real test site, the MAPEs of the simulations are 13.52 ~ 38.80% for changes of HCHO concentrations in 20 min interval with mass balance model and CONTAM. The MAPEs of HCHO for CONTAM simulations is 5.38%, which shows the CONTAM has good.

Calcium carbonate nanoparticles stimulate cancer cell reprogramming to suppress tumor growth and invasion in an organ-on-a-chip system

The acidic microenvironment of solid tumors induces the propagation of highly invasive and metastatic phenotypes. However, simulating these conditions in animal models present challenges that confound the effects of pH modulators on tumor progression. To recapitulate the tumor microenvironment and isolate the effect of pH on tumor viability, we developed a bifurcated microfluidic device that supports two different cell environments for direct comparison. RFP-expressing breast cancer cells (MDA-MB-231) were cultured in treatment and control chambers surrounded by fibrin, which received acid-neutralizing CaCO3 nanoparticles (nanoCaCO3) and cell culture media, respectively. Data analysis revealed that nanoCaCO3 buffered the pH within the normal physiological range and inhibited tumor cell proliferation compared to the untreated control (p < 0.05). Co-incubation of cancer cells and fibroblasts, followed by nanoCaCO3 treatment showed that the nanoparticles selectively inhibited the growth of the MDA-MB-231 cells and reduced cellular migration of these cells with no impact on the fibroblasts. Sustainable decrease in the intracellular pH of cancer cells treated with nanoCaCO3 indicates that the extracellular pH induced cellular metabolic reprogramming. These results suggest that the nanoCaCO3 can restrict the aggressiveness of tumor cells without affecting the growth and behavior of the surrounding stromal cells.

Simulation Analysis and Parameter Optimization of The Electronic Controlled Injector

In order to improve the dynamic response characteristics of the electronic controlled injector, a simulation model for the response characteristics of the electronic controlled injector was established. By comparing the calculation results of the simulation model with the experimental results, the validity and accuracy of the model are verified. The influence of inlet hole diameter, outlet hole diameter and needle valve diameter on the dynamic response characteristics of the needle valve of the electronic control injector was studied. The results show that the closing delay time of the needle valve decreases with the increase of the inlet hole diameter of the control chamber, the opening delay time of the needle valve decreases with the increase of the oil outlet diameter of the control chamber, and the closing delay time of the increase of the diameter of the needle valve and the opening delay time decreases. An orthogonal experiment with three factors and four levels was designed to optimize the structural parameters of the electronic control injector. The optimized results show that the dynamic response characteristics of the injector are improved.

Climate Warming Decreases Plant Diversity but Increases Community Biomass in High-Altitude Grasslands

The rugged Himalayan landscape results in large variations in site conditions that regulate plant response to warming. There is lack of deeper understanding on plant response to warming under differing site characteristics in the mountainous terrain. A 2-yr experiment was conducted in the high mountains of Bhutan. The objective was to investigate the effects of short-term artificial warming on high-altitude grassland vegetation at north- and south-facing sites. An artificially warmed environment was simulated using open-top chambers (OTCs) that were compared with control chambers experiencing ambient conditions. Variables measured were species diversity, species richness, proportions of plant functional groups, forage dry matter, and forage quality. Generally at the north-facing site, OTC treatment showed a lower species diversity (OTC treatment H' ≈2.35; Control treatment H' ≈2.75), species richness (OTC treatment MI ≈1.38; Control treatment MI ≈1.45), sedge abundance (OTC treatment sedge cover ≈14.5%; Control treatment sedge cover ≈25%), and crude protein content (OTC treatment CP ≈6.60%; Control treatment CP ≈7.70%). On both sites, OTC treatment had a higher grass abundance (OTC treatment grass cover ≈24.0%; Control treatment grass cover ≈17.0%) and higher dry matter content (OTC treatment DM ≈1.70 t ha−1; Control treatment DM ≈1.50 t ha−1). The study suggests that climate warming triggers shifts in vegetation characteristics of high-altitude grasslands in the rugged mountainous terrain, but the magnitude of shift varies according to site characteristics. Under warming, the north-facing site could experience greater vegetation change, characterized by reduced species diversity, species richness, proportion of sedge, and crude protein content.

System Modelling and Analysis on Stability of Electro-Hydraulic Pressure Regulating System for Shift Actuator including an Accumulator

Abstract The shift actuator of wet clutch adopt an electro-hydraulic pressure regulating system (EHPRS), which play a critical role to shifting quality. Related research shows that the accumulator can improve the stability of output pressure for EHPRS, but its working mechanism and influence law are not clear yet. In this paper, a spring-type accumulator that connected in parallel in the control chamber of EHPRS is studied and analyzed. Firstly, the system mechanism is analyzed; then, the mathematical model and simulation model of system are established; finally, based on the simulation model, the dynamic characteristics of system are analyzed, and the influence of accumulator on the stability performance is revealed. The results show that under the same conditions, the accumulator can significantly reduce the overshoot of output pressure and shorten the stabilization time of output pressure, without affecting the pressure build-up time of output pressure. At the same time, with the increase of accumulator orifice and spring stiffness, the stability of system is significantly improved. It provides reference value for system design.

Impact of a modified braking valve for static and dynamic characteristics of pneumatic braking systems of agricultural trailers

Pneumatic braking systems of agricultural trailers contain brake valves with adjustable predominance of the output pressure relative to the control pressure. The goals of our study were to improve the static and dynamic properties of agricultural trailer pneumatic braking systems by modification of brake valve construction with implementing a throttle valve to the predominance device in valve. Proposed correction device ensures that the intensity of the predominance effect depends on the rate of pressure rise in control chamber of the braking valve. Initial testing of three agricultural trailers' braking systems has confirmed the effect of modifying relay emergency valve to shortening the response time of their braking systems while maintaining a follow-up action under steady state conditions.

The effect of illumination with different light wavelengths on the orientation of Turkestan cockroach, Blatta lateralis (Walker,1868) (Blattodea: Blattidae)

Bu calismada, farkli dalga boylarina (kirmizi, yesil, sari, mavi, beyaz ve karanlik) sahip isinlarin Turkistan hamambocegi, Blatta lateralis (Walker,1868) (Blattodea: Blattidae)’in yonelimi uzerindeki etkisi arastirilmistir. Calisma, 2019 yilinda Bursa Uludag Universitesi’nde laboratuvar kosullarinda yurutulmustur. Yonelim denemelerinde, ergin hamambocekleri uc farkli isik siddetine (25, 250 ve 2500 luks) maruz birakilmistir. Denemeler 6-kollu ve 2-kollu secimli olarak yurutulmustur. Tum denemelerde 3 tekerrur ve her tekerrurde 100 birey kullanilmistir. Elde edilen veriler, isik siddetine bagli olarak farkli dalga boyuna sahip isinlara yonelim hassasiyetinin artabilecegini gostermektedir. Ozellikle, alti -kollu ve iki -kollu denemede, 2500 luks siddetinde mavi isik uygulandiginda, hamamboceginin yonelimi en dusuk seviyede olup, sirasiyla, %0.9 ve %1.8 oraninda olmustur. Genel olarak en yuksek yonelim, tum denemelerde karanlik (kontrol) odaciga olmustur. Ayrica tum luks degerleri altinda kirmizi isiga yonelim, yesil, sari, mavi ve beyaz isiga gore daha fazla olmustur. Bu calisma sonucunda, mavi isigin hamambocekleri uzerinde kacirici bir etki gosterebilecegi, kirmizi isigin ise diger dalga boylarina gore daha cekici olabilecegi tespit edilmistir. Yapilan bu calismalar, hamamboceklerine karsi kullanilan kimyasallarin yerini alabilecek insan sagligina ve cevreye zararsiz olan alternatif bir mucadele metodunun gelistirilmesinde faydali olabilir.

Olfactory Choice for Decomposition Stage in the Burying Beetle Nicrophorus vespilloides: Preference or Aversion?

Simple SummaryIn the burying beetle Nicrophorus vespilloides, mating pairs raise their offspring together on a small carrion resource. We tested whether carcass age affected brood quantity and quality and found that pairs had significantly more offspring on fresher carcasses. To determine whether this reproductive benefit translates to an olfactory preference or aversion for carcass age, we conducted a series of olfactory trials testing adult mated female preferences for carcasses differing in age. Mated females spent more time associating with fresh carcass odors relative to those of an aged one, but also spent more time in empty chambers than those with an aged carcass, suggesting that mated females have a general aversion to those odors. Lastly, we characterized the odor profiles of fresh and aged carcasses to determine which compounds might be driving this olfactory aversion in mated female burying beetles.Sensory cues predicting resource quality are drivers of key animal behaviors such as preference or aversion. Despite the abundance of behavioral choice studies across the animal kingdom, relatively few studies have tested whether these decisions are driven by preference for one choice or aversion to another. In the burying beetle Nicrophorus vespilloides, adult pairs exhibit parental care to raise their offspring on a small carrion resource. We tested whether carrion decomposition stage affected brood quantity and quality and found that mating pairs had significantly more offspring on fresher carcasses. To determine whether this observed reproductive benefit correlates with maternal preference behavior, we conducted a series of olfactory trials testing mated female preferences for mouse carcasses of differing decomposition stages. When given the option between fresh and older carcasses, females associated significantly more with fresher, 1-day old carcasses. However, this behavior may be driven by aversion, as females that were given a choice between the 7-day old carcass and a blank control spent significantly more time in the control chamber. We characterized volatile organic compound profiles of both carcass types, highlighting unique compounds that may serve as public information (sensu lato) conveying resource quality information to gravid beetles.

Manufacturing Process of Electrode Films

Rotating disk electrode experiments form a key experimental characterization technique for measuring electrocatalyst performance and durability. Numerous studies have been performed to gauge catalyst performance and suitability for polymer electrolyte fuel cells. However, those studies can show for a wide range of performance measurements for the same catalyst.1 Standard rotating disk electrode testing protocols have been documented, and used repeatedly in available literature.1 Little research has been devoted to the catalyst film preparation however. Catalyst films are formed from the drying of a catalyst solution consisting of a catalyst-water-ethanol-Nafion solution on a glassy carbon working electrode surface. Experiments within our group show large variation in catalyst performance characterization for catalyst films dried under ambient conditions, which result from inconsistent and non-uniform catalyst distribution on the electrode surface. To promote consistent film production, a controlled environmental chamber was constructed. The objective of this chamber was to establish conditions for equalizing water and alcohol evaporation in the catalyst solution by controlling relative humidity. Catalyst film quality was shown to improve when using the chamber, improving film catalyst distribution uniformity, along with electrochemical catalyst performance. This paper will detail the construction and the environmental control chamber, and the effect of environmental conditions on the catalyst film quality and electrochemical measurements.Reference1. S. Kocha et al., “Best Practices and Testing Protocols for Benchmarking ORR Activities of Fuel Cell Electrocatalysts Using Rotating Disk Electrode,” Electrocatalysis, vol. 8, no. 4, pp. 366–374, Jul. 2017, doi: 10.1007/s12678-017-0378-6. Figure 1

A Tissue Engineering Chamber for Continuous Pulsatile Electrical Stimulation of Vascularized Cardiac Tissues In Vivo.

Background: Cardiomyocytes derived from pluripotent stem cells are immature. Maturation of cardiomyocytes is a multifactorial dynamic process that involves various factors in vivo that cannot be fully recapitulated in vitro. Here, we report a novel tissue engineering chamber with an integrated electrical stimulator and electrodes that will allow wireless electrical stimulation of cardiac tissue in vivo. Materials and Methods: Immunocompromised rats were implanted with tissue engineering chambers containing the stimulator and electrodes, and control chambers (chambers with electrical stimulator but without the electrodes) in the contralateral limb. Each chamber contained cardiomyocytes derived from human induced pluripotent stem cells (iPSCs). After 7 days of chamber implantation, the electrical stimulators were activated for 4 h per day, for 21 consecutive days. Results: At 4 weeks postimplantation, cardiomyocytes derived from human iPSCs survived, were assembled into compact cardiac tissue, and were perfused and vascularized by the host neovessels. Conclusion: This proof-of-principle study demonstrates the biocompatibility of the tissue engineering chamber with integrated electrical stimulator and electrodes. This could be utilized to study the influence of continuous electrical stimulation on vascularized cardiac or other tissues in vivo.

De novo transcriptome assembly of cold stressed clones of the hexaploid Sequoia sempervirens (D. Don) Endl.

Coast redwood is a very important endemic conifer timber species in Southern Oregon and Northern California in the USA. Due to its good wood properties and fast growth rate it can be considered as a prospective timber species also in other countries with similar or changing toward similar climatic conditions due to global climate warming, such as Germany. In general, it is frost sensitive and suffers from freezing temperatures. To study genetic mechanisms of frost resistance in this species and to select the most frost tolerant trees we tested 17 clones in climate control chamber experiments and generated two de novo assemblies of the coast redwood transcriptome from a pooled RNA sample using Trinity and CLC Genomic Workbench software, respectively. The hexaploid nature of the coast redwood genome makes it very challenging to successfully assemble and annotate the coast redwood transcriptome. The de novo transcriptome assembly generated by Trinity and CLC considering only reads with a minimum length of 180 bp and contigs no less than 200 bp long resulted in 634,772 and 788,464 unigenes (unique contigs), respectively.

Cold programming of epoxy-based shape memory polymer

Shape Memory Polymers (SMPs) are the class of smart materials that show ability to memorize different shapes and regain original shape. The conventional method is to heat SMP above its glass transition temperature (Tg) and deform it to obtain the desired shape. It reverts to original shape upon heating. This is known as hot programming. Recent advances in the programming of SMP have shown promising results of a new programming method also known as cold programming. The SMP is plastically deformed at a temperature below Tg to impart the desired shape. This paper aims at the experimental investigation of shape memory properties of Epoxy-based SMPs using the cold programming method. The polymers of Epoxy used in this work are Diglycidyl Ether of Bisphenol-A (DGEBA) and Neopentyl Glycol Diglycidyl Ether (NGDE). The mechanical properties like elastic modulus, tensile strength, and failure strain have been found for different ratios of DGEBA and NGDE at various temperatures. The Tg of different compositions has been measured using Differential Scanning Calorimetry (DSC). In this work, a candidate material has been identified based on its mechanical and shape memory properties. It has been demonstrated that important properties of material like glass transition temperature, elastic modulus, and strength can be tailored according to the need by changing the ratio of constituents. A dedicated experimental setup consisting of Uniaxial Tensile Machine (UTM), temperature control chamber, and a camera for Digital Image Correlation (DIC) has been used to carryout thermomechanical cycles of SMP. The parameters that affect the performance of cold programming like stress-relaxation time, structural relaxation time, and operating temperature have been studied. The stress-strain response for a complete shape memory cycle has been measured. Parameters determining the shape memory capabilities like shape fixity, recovery ratio, recovery speed of the material were evaluated. The merits and demerits of cold programming over other programming methods have been discussed by carrying out required experiments. The differences in both the programming methods and the underlying mechanism of shape memory effect have been discussed briefly in this paper. Present work is limited to the study of SMP for uniaxial tensile cases undergoing large deformation with small strain-rate and low rate of heating and cooling.

Evaluation of pumice for development of low-cost and energy-efficient composite phase change materials and lab-scale thermoregulation performances of its cementitious plasters

Integration of a building mass with a phase change-energy storage material is able to improve its thermal efficiency. With this respect, pumice was evaluated as low-cost supporting material for development of energy-efficient composites containing capric acid (CA) and polyethylene glycol(PEG) as phase change material (PCM). The developed leak-proof composites was also incorporated separately with ordinary cement (OC; Portland Cement) to produce novel plaster with thermal energy storage (TES) ability for thermoregulation of buildings. The DSC analysis results demonstrated that the shape-stabilized composite PCMs (S-SCPCMs) had melting temperatures of 31.03 °C and 8.80 °C and TES capacity of 116.27 J/g and 98.39 J/g, respectively. Cycling thermal degradation stability and TES dependability of the leak proof composites were examined by TGA techniques. The lab-scale test revealed that the indoor center temperatures (ICT) of the cubic chambers plastered separately by pumice/CA/OC and pumice/PEG/OC mortars were maintained at comfortable temperature range for relatively longer times compared to the control chamber plastered by OC mortar.