Dry Ambient Conditions Research Articles

Sliding wear characteristics of as-deposited and heat-treated electroless Ni-P coatings against AISI E52100 steel ball

In the present experimental study, the wear characteristics of as-deposited and heat-treated, nickel phosphorus (Ni-P) coatings were studied against bearing steel ball (AISI E52100) at ambient dry conditions using linear reciprocating tribometer. The Ni-P coatings were deposited on En24 grade steel using electroless acidic bath and subjected to heat treatment at 400 °C for 1 h under air atmosphere. The phase structure and surface morphology of the coatings were characterized using x-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), respectively. Grain size of the coatings was analysed using Scherrer technique. Heat-treated coatings showed 50% improvement in Vickers hardness compared to as-deposited coatings, which is attributed to the formation of Ni3P phase. The stable friction coefficient (∼0.21) and low specific wear rate (4.49E-05 mm3/N-m) were observed for heat-treated coatings in comparison to those of as-deposited coatings. Wear tracks were characterized using SEM and energy dispersive spectroscopy (EDS) in order to understand the wear mechanisms.

Improved CO2 flux by dissolution of oxide ions into the molten carbonate phase of dual-phase CO2 separation membranes

In a solid-liquid dual-phase CO2 separation membrane, the native ions in the molten alkali carbonate, including carbonate anions and metal cations can transport CO2 in a process that is charge-compensated by electronic species (electrons or holes), oxide ions, or hydroxide ions, depending on materials and conditions. This strongly affects the design of experiments for assessing the performance of these membranes, and further determines the routes for integration of these membranes in industrial applications. Here we report how dissolved oxides in the liquid carbonate improve the CO2 flux of the membrane due to an enhanced charge-compensating oxygen ion transport. A qualitative understanding of the magnitude and role of oxide ion conductivity in the molten phase and in the solid support as a function of the temperature is provided. Employing a solid matrix of ceria, and dissolving CsVO3 and MoO3 oxides in the molten carbonate phase led to an almost doubled CO2 flux at 550 °C under dry ambient conditions. When the sweep gas contained 2.5% H2O, the CO2 flux was increased further due to formation of hydroxide ions in the molten carbonate acting as charge compensating species. Also, as a consequence of permeation controlled by ions in the liquid phase, the CO2 flux increased with the pore volume of the solid matrix.

Influence of dry ambient conditions on performance of underground medium-voltage DC cables

In its publication IEC 60287, the International Electrotechnical Commission recommends procedures for thermal analysis of power cables in the presence of a dry-out zone in the surrounding medium. It is well known, that the ampacity of cables depends strongly on the so-called critical temperature at which the surrounding medium dries out. However, research on how to estimate this critical temperature has been limited. In semi-arid Mediterranean climate regions, dry summers typically lead to a decrease of the critical temperature. In this paper, the critical temperature is calculated for a field in Riverside, California under various ambient conditions. This is done from the numerical solution of the differential equation for moisture content in the planar case of steady-state coupled heat and mass transfer in porous media. Finite-difference simulations of a system of two medium-voltage DC cables in this field are performed with SHEMAT-Suite (Simulator of HEat and MAss Transport) to compute the maximum temperature for daily cases of calculated critical temperature and compared to a prediction from IEC 60287. It is found that large day-to-day variations in field conditions in a semi-arid area may significantly affect the maximum allowable current. Our results emphasize the importance of ambient conditions for the cable performance.

Tribological Behavior of the 316L Stainless Steel with Heterogeneous Lamella Structure.

In this paper, the tribological behavior of 316L stainless steel with heterogeneous lamella structure (HLS), prepared through 85% cold rolling technology and subsequent annealing treatment (750 °C, 10 min), were conducted on a ball-on-disc tribometer under different normal loads in dry ambient air conditions. The morphologies, structures, and compositions of the raw and worn surfaces were analyzed by 3D surface profilometer, XRD, SEM, EDS and TEM. Based on this, the results showed that the HLS 316L stainless steel samples exhibited lower and more steady friction coefficients than coarse-grained samples, especially under higher loads, which can be attributed to the existence of numerous oxidative particles across sliding interfaces. However, the wear resistance of HLS 316L stainless steel sample was a little weakened compared to that of the coarse-grained sample under a normal load of 5 N. When the load increases up to 15 N, an obviously decreased wear resistance was found for the HLS of the 316L stainless steel sample, which was 50% lower than that of coarse-grained sample. This can be ascribed to the more severe oxidative and abrasive wear performance of HLS 316L stainless steel sample under dry sliding conditions.

Mechanical, thermal and acoustic properties of cellular alkali activated fly ash concrete

This article characterizes a cellular system prepared from alkali activated Class C fly ash mixed with a preformed foam. The resulting mixture was cast at three densities between 1000 and 1400 kg/m3 and all tests were conducted under ambient drying conditions resulting in densities between 940 and 1310 kg/m3. A phase analysis of the components in the cell wall was performed using X-ray diffraction. The compressive strength ranged from 3 to 9 MPa, while the corresponding modulus of elasticity was between 850 and 1700 MPa. The thermal constants were measured using the Transient Plane Heat Source (TPS) technique per ISO 22007-2. Sound absorption and noise reduction coefficients were evaluated using the impedance tube method per ASTM C384-04. The results show that at an oven dry density near 1000 kg/m3, this alkali activated system is a viable alternative for thermal and sound insulation with properties comparable to those of current commercially available options.

Superabsorbent polymers to mitigate plastic drying shrinkage in a cement paste as studied by NMR

At early ages, a problem of plastic shrinkage can arise when a cement paste is subjected to harsh drying conditions during hardening. SuperAbsorbent Polymers (SAPs) are a promising admixture to mitigate shrinkage in cement pastes. By introducing internal curing by means of the stored mixing water in the SAPs, the plastic shrinkage can be partially mitigated, next to the mitigation of autogenous shrinkage during setting of the cement paste. The kinetics of water release by the SAPs towards the cementitious matrix have been studied in detail to understand the mechanism. Nuclear Magnetic Resonance (NMR) is an effective technique to non-destructively monitor the effects induced by the SAPs during this plastic period and hardening as a function of time. The SAPs are able to protect the cement paste internally from the harsh ambient drying conditions and are able to sustain the internal relative humidity. The plastic settlement was reduced and there was less plastic shrinkage measured. Below 5 mm of the surface in SAP specimens, the specimens were hardening as if put in sealed conditions.

Enhancing tribological performance of Ti-6Al-4V by sliding process

ABSTRACTThe exceptional combination of mechanical, physical and anti-corrosive properties of Titanium alloy Ti-6Al-4 V (Ti64) makes it idle material for the applications like aerospace, automobile, chemical, medical etc. However, Ti64 exhibits poor tribological (friction and wear) properties, which limits its implementation in the intended applications. The tribological performance of the Ti64 can be enhanced by developing a protective layer or coating on its surface. It has been reported in literatures that through rubbing process the oxide layers can be achieved at much lower temperature compared to external heating process. Therefore, an endeavour is made in the present work to achieve a tribo-oxide protective layer on the surface of Ti64 through rubbing process. For this, at first the tribological behaviour of tribo pair: Ti64 pin-alumina disc is studied under dry ambient condition for diverse loading and sliding speed conditions, using pin on disc experimental set-up. The obtained results are compared with literatures. The tribological performance is quantified in terms of coefficient of friction (COF) and wear rate. To investigate the tribological mechanism and behaviour, in-situ analysis was performed on the pin’s surface using (i) scanning electron microscopy, and (ii) energy dispersive analysis of X-ray. The mechanical properties like nano-hardness and elastic modulus of the pins surface were also determined. It was envisaged that the tribological behaviour were extremely transient and depend greatly on what the surface has precisely experienced Based on the experimental observations, the experimental conditions providing (i) Case1: deprived tribological properties and (ii) Case 2: higher oxide layer is selected. Now, to enhance the tribological behaviour of Case 1, the pin with high oxide layer, i.e. Case 2 is used. For this experiment is performed initially for Case 2 conditions for the sliding distance of 1000 m (for developing oxide layer) and the experiment is continued for next 1000 m for Case 1 condition. The experimental results in terms of COF and wear rate are presented and corresponding enhancement in their values are discussed.

Prevalence of Exercise Induced Bronchoconstriction in Recreational Adult Hockey Players as determined by Sport Specific Field Exercise Challenge Test

BACKGROUND: Exercise induced bronchoconstriction (EIB) is provoked by exercise and results in narrowing of the airways. Studies have shown an EIB prevalence of 11-50% in athletic populations. The diagnosis of EIB is dependent upon objective measurement of respiratory function, as respiratory symptoms are unreliable. Cold and dry ambient conditions contribute to the severity of EIB. The environmental conditions and manner of exertion an athlete is exposed to in ice hockey are significantly different than any current standardized laboratory test to evaluate for EIB. In a prior study of elite women hockey players, 39.5% presented symptoms of asthma and 21% demonstrated EIB. Sport-specific field exercise challenge tests (SSFECT) have been validated for the assessment of EIB, and are more sensitive than laboratory challenges in elite winter athletes. PURPOSE: To use a SSFECT to determine the prevalence of EIB in adult recreational ice hockey players, and the correlation between reported symptoms and diagnosis by this method. METHODS: Participants were 18 males and 2 females (mean age of 34.7 yrs, mean height of 1.78 m); who participated in 1 of 2 recreational ice hockey leagues in Chicago, IL. Using a Piko-1 portable spirometer, FEV1 was measured prior to the hockey game and immediately following periods 1, 2, and 3. All respiratory measurements occurred with hockey equipment adorned. Airway response was expressed as the percent fall in FEV1 from the baseline value. Diagnosis of EIB was given if athletes had a greater than 10% decrease in FEV1 from baseline measured at any time point. Athletes also completed an intake questionnaire prior to testing which included clinical symptoms, exercise history, and past medical history. RESULTS: EIB was diagnosed in 3/20(15%) athletes. A prior diagnosis of asthma or exercise induced asthma was reported in 5/20 (25%) athletes, yet only one of these had a decrease of > 10 % of FEV1 as measured by this test. Of the three EIB+, two were symptomatic (67%); and of the EIB-, 9/17 (53%) reported respiratory symptoms. Diagnosis of EIB was consistent for all three periods in all but one athlete. Mean FEV1 for the three periods was 4.08, 4.07, and 4.07 respectively. CONCLUSIONS: Symptoms remain unreliable for diagnosis of EIB. SSFECT can be utilized for diagnosis of EIB in ice hockey athletes.

Water sensitivity of fluorine-containing polyacrylate latex coatings: Effects of crosslinking and ambient drying conditions

In this study, fluorine-containing polyacrylate latexes comprising different levels of copolymerized perfluorethyl groups were prepared by the two-stage emulsion polymerization of 2,2,2-trifluoroethyl methacrylate, methyl methacrylate, butyl acrylate and methacrylic acid as main monomers, where the fluorine-containing monomer was copolymerized only into the second stage polymer. The effects of keto-hydrazide self-crosslinking and its combination with pre-coalescence and ionomeric crosslinking, respectively, on coating wettability, water absorption and water whitening were investigated. For the keto-hydrazide self-crosslinking, diacetone acrylamide was copolymerized into the second stage polymer to provide sites for the subsequent reaction with adipic acid dihydrazide. The pre-coalescence crosslinking of latex particles was introduced by copolymerizing allylmethacrylate during the synthesis and the ionomeric crosslinking was provided by the addition of a commercial zinc complexing agent. The influences of ambient conditions during the film-forming process in terms of temperature and relative humidity differences on coating wettability were evaluated. Further, changes of coating wettability as a function of water exposure duration were tested. The results showed that the highest level of hydrophobicity at the same amount of copolymerized 2,2,2-trifluoroethyl methacrylate could be achieved in the case of non-crosslinked latex films dried at elevated temperatures, whereas the highly crosslinked latexes combining pre-coalescence crosslinking and keto-hydrazide self-crosslinking provided the most water whitening-resistant coating films.

Tribological behavior of αı/βı-SiAlON-TiN composites

There are limited studies on the tribological properties of SiAlON-TiN composites. Therefore, in the present study, tribology tests were conducted on a number of αı/βı-SiAlON-TiN composites with different αı/βı-SiAlON phase ratio and TiN content, fabricated with unique compositional design. The influence of αı/βı-SiAlON phase ratios, microstructure, mechanical properties and TiN content on friction and wear behavior was investigated and wear mechanisms were explained. Tribology tests were conducted on computer controlled tribometer under dry unlubricated ambient conditions with a linear reciprocating movement in a ball-on-disc sliding wear configuration and test parameters kept as constant. It was observed that TiN addition (17 wt.%) did not change the friction (CoF) of SiAlON and wear rate and wear volume were observed to increase. Wear mechanisms showed differences with αı:βı-SiAlON phase ratio. Fracture toughness had very pronounced effect on wear resistance.

Wear behavior and XRD analysis of reinforced copper matrix composite reinforced with Cerium Oxide (CeO2)

In this work, tribological behavior of Copper-Cerium Oxide metal powder composite reinforced with CeO2 particles has been assessed experimentally. Four number of Cylindrical preforms with different CeO2 content (0 wt. %, 0.2 wt. %, 0.6 wt. % and 1 wt. %) at 90 KN compaction pressure have been prepared using a die and punch assembly on Universal Testing Machine by Powder Metallurgy root. Sintering at different temperatures of 900°C, 950°C and 1000°C has been carried out using Electrical Muffle Furnace (EMF). The sliding wear behavior of 12 mm diameter cylindrical sample was performed on a pin-on-disc wear tester against EN-32 steel disc (applied load 10 KN, distance 4 KM at 800 rpm) under dry ambient conditions. Finally, SEM (scanning electron microscopy) and XRD analysis has been carried out to investigate crystal grain structure and to identify the crystalline face. Densification and hardness of specimen is increased with increase of CeO2 percentage and sintering temperature. Wear decreases with increase of CeO2 content and sintering temperature when experimented. SEM and XRD test confirm uniform distribution of Cerium Oxide in copper matrix. Diffraction pattern indicates good solubility of CeO2 in copper matrix

Ambient mineral carbonation of different lithologies of mafic to ultramafic mining wastes/tailings – A comparative study

Four lithologies of the Dumont nickel project were studied for assessing the carbonation capacity in ambient conditions of waste rocks and mineral processing tailings consisting of dunite, peridotite, gabbro, and volcanic materials. Mineral carbonation of these mine waste and tailing minerals is contemplated as a premium solution to permanently trap atmospheric CO2 into solid carbonates using a differential batch carbonation cell and carbonate precipitation columns. The different mafic to ultramafic lithologies of the Dumont nickel project were characterized before and after carbonation by means of X-ray diffraction and thermogravimetry analyses, Fourier transform infrared spectroscopy, optical microscopy, and quantitative evaluation of minerals by scanning electron microscopy. It was found that for identical size fractions, carbonation of rock wastes was quite limited as compared to the tailings. Brucite more abundant in dunite and peridotite substrates was found to be the main reactant involved in carbonation as compared to other less-reactive magnesium silicate minerals. Nesquehonite, the prevalent magnesium carbonate species formed in wet ambient carbonation, remained stable despite prolonged exposition in dry ambient air conditions. Finally, some design recommendations were formulated to overcome the dilemma due to separate storage of high-permeability brucite-poor (lowly reactive) waste rock stockpiles, and finely-ground low-permeability brucite-rich (highly reactive) tailings.

Facile synthesis of highly conducting and mesoporous carbon aerogel as platinum support for PEM fuel cells

We report novel method for synthesis of carbon aerogel as platinum support for PEM fuel cells applications. The sol gel polymerization has been carried out using resorcinol and furfuraldehyde in non-aqueous medium followed by gelation at high pressure. This resulted in highly conducting and mesoporous carbon aerogel under ambient drying conditions. Platinum nano-particles are impregnated in the mesoporous carbon aerogel using microwave assisted polyol process. The support material and the catalyst are characterized by different analytical techniques like surface area analyzer, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry and linear sweep voltammetry are used to evaluate the electro–catalytic activity of the Pt/carbon aerogel catalyst using rotating disk electrode technique. Well dispersed Pt nano-particles of size ∼3 nm on carbon aerogel showed good catalytic activity with onset potential of 964 mV and half wave potential of 814 mV towards oxygen reduction reaction kinetics. A membrane electrode assembly fabricated with the prepared Pt/carbon aerogel catalyst as a cathode and anode is tested in PEMFCs (H2O2) single cell, the power density of 536 mW cm−2 at 0.6 V is obtained at 60 °C under atmospheric pressure.

Thermal Regime Effect on Gas-Transport Lines in the Persian Gulf

Summary Sea lines transporting gas toward the north (Iran) and south (Qatar and Saudi Arabia) and originating from fields located in the central parts of the Persian Gulf exhibit different thermal regimes. The lowest reported arrival temperatures of the gas were 18 and 11°C for the sea lines transporting gas to the northern and southern shores, respectively. The difference between the two is significant and could radically alter the hydrate-mitigation strategy and the associated economics. Metocean data reported in this study and from previous studies (Appendix A) show that the northern part of the Persian Gulf, which is also deeper, attains a well-mixed state during winter months. During this phase, the arrival temperature of the gas for South Pars (SP) sea lines decreases steadily and goes through a minimum at approximately the middle of February every year. In the southern region, the sea is shallow and water is more saline. Sinking of saline water when exposed to cool and dry ambient winter conditions is probably responsible for the reported abrupt decrease in arrival temperatures in the case of the Karan gas line. The immediate recovery of the same may be caused by the local wind/tide conditions. The likely origins of the observed lowest temperatures in the north and south regions are Arctic winds of short duration and desert winds of fairly long duration, respectively. This study summarizes hydrate-inhibition practices for these sea lines, and indicates a possibility of using the sea lines as “indirect thermometers” to provide important physical oceanographic data for long terms in a limited but economical way with fewer interruptions.

Oxygen delivery using engineered microparticles

A continuous supply of oxygen to tissues is vital to life and interruptions in its delivery are poorly tolerated. The treatment of low-blood oxygen tensions requires restoration of functional airways and lungs. Unfortunately, severe oxygen deprivation carries a high mortality rate and can make otherwise-survivable illnesses unsurvivable. Thus, an effective and rapid treatment for hypoxemia would be revolutionary. The i.v. injection of oxygen bubbles has recently emerged as a potential strategy to rapidly raise arterial oxygen tensions. In this report, we describe the fabrication of a polymer-based intravascular oxygen delivery agent. Polymer hollow microparticles (PHMs) are thin-walled, hollow polymer microcapsules with tunable nanoporous shells. We show that PHMs are easily charged with oxygen gas and that they release their oxygen payload only when exposed to desaturated blood. We demonstrate that oxygen release from PHMs is diffusion-controlled, that they deliver approximately five times more oxygen gas than human red blood cells (per gram), and that they are safe and effective when injected in vivo. Finally, we show that PHMs can be stored at room temperature under dry ambient conditions for at least 2 mo without any effect on particle size distribution or gas carrying capacity.

Novel methodology to perform sulfur hexafluoride (SF6)-based multiple-breath wash-in and washout in infants using current commercially available equipment.

Multiple-breath inert gas washout (MBW) is ideally suited for early detection and monitoring of serious lung disease, such as cystic fibrosis, in infants and young children. Validated commercial options for the MBW technique are limited, and suitability of nitrogen (N2)-based MBW is of concern given the detrimental effect of exposure to pure O2 on infant breathing pattern. We propose novel methodology using commercially available N2 MBW equipment to facilitate 4% sulfur hexafluoride (SF6) multiple-breath inert gas wash-in and washout suitable for the infant age range. CO2, O2, and sidestream molar mass sensor signals were used to accurately calculate SF6 concentrations. An improved dynamic method for synchronization of gas and respiratory flow was developed to take into account variations in sidestream sample flow during MBW measurement. In vitro validation of triplicate functional residual capacity (FRC) assessments was undertaken under dry ambient conditions using lung models ranging from 90 to 267 ml, with tidal volumes of 28-79 ml, and respiratory rates 20-60 per minute. The relative mean (SD, 95% confidence interval) error of triplicate FRC determinations by washout was -0.26 (1.84, -3.86 to +3.35)% and by wash-in was 0.57 (2.66, -4.66 to +5.79)%. The standard deviations [mean (SD)] of percentage error among FRC triplicates were 1.40 (1.14) and 1.38 (1.32) for washout and wash-in, respectively. The novel methodology presented achieved FRC accuracy as outlined by current MBW consensus recommendations (95% of measurements within 5% accuracy). Further clinical evaluation is required, but this new technique, using existing commercially available equipment, has exciting potential for research and clinical use.

A study on the release kinetics and mechanisms of vanillin incorporated in almond gum/polyvinyl alcohol composite nanofibers in different aqueous food simulants and simulated saliva

AbstractVanillin incorporated almond gum/polyvinyl alcohol (PVA) composite nanofibers were prepared using electrospinning. The release mechanisms and kinetics of incorporated vanillin were evaluated in different aqueous food simulants (distilled water, 10% ethanol, 50% ethanol and 3% acetic acid) and simulated saliva. Vanillin content in different media was determined by high‐performance liquid chromatography (HPLC). Vanillin release data were fitted to first order, Kopcha, Korsmeyer‐Peppas and Peppas‐Sahlin models to evaluate release mechanisms and kinetics. Release kinetics of vanillin in all mentioned media followed a pseudo‐Fickian diffusion mechanism. The vanillin release data in distilled water, 10% ethanol, 50% ethanol and simulated saliva fitted well to Peppas‐Sahlin model with regression coefficients 0.9937, 0.9936 and 0.9912, 0.9903, respectively. The release kinetics of vanillin in 3% acetic acid fitted to the Korsmeyer‐Peppas model with regression coefficient 0.9661. The release study in different aqueous food simulants showed burst release of vanillin within the first 5 min, followed by sustained release for 180 min. Nanofibers showed relatively good stability under dry ambient condition and maintained around 58 percentage of the incorporated vanillin for 90 days. Copyright © 2016 John Wiley & Sons, Ltd.

Heat and Mass Transfer Analysis of a Pot-in-Pot Refrigerator Using Reynolds Flow Model

Heat and mass transfer analysis of evaporative cooling process in a pot-in-pot cooling system is done based on Reynolds flow hypotheses. The model proposed herein assumes that the heat transfer due to natural convection is coupled with an imaginary ambient air mass flow rate (gAo) which is an essential assumption in order to arrive at the solution for the rate of water evaporation. Effect of several parameters on the pot-in-pot system performance has been studied. The equations are iteratively solved and detailed results are presented to evaluate the cooling performance with respect to various parameters: ambient temperature, relative humidity (RH), pot height, pot radius, total heat load, thermal and hydraulic conductivity, and radiation heat transfer. It was found that pot height, pot radius, total heat load, and radiation heat transfer play a critical role in the performance of the system. The model predicts that at an ambient temperature of 50 °C and RH of 40%, the system achieves a maximum efficiency of 73.44% resulting in a temperature difference of nearly 20 °C. Similarly, for a temperature of 30 °C and RH of 80%, the system efficiency was minimum at 14.79%, thereby verifying the usual concept that the pot-in-pot system is best suited for hot and dry ambient conditions.

Severe wear behaviour of alumina balls sliding against diamond ceramic coatings

At present alumina is the most widely used bio-ceramic material for implants. However, diamond surface offers very good solid lubricant for different machinery, equipment including biomedical implants (hip implants, knee implants, etc.), since the coefficient of friction (COF) of diamond is lower than alumina. In this tribological study, alumina ball was chosen as the counter body material to show better performance of the polycrystalline diamond (PCD) coatings in biomedical load-bearing applications. Wear and friction data were recorded for microwave plasma chemical vapour deposition (MWCVD) grown PCD coatings of four different types, out of which two samples were as-deposited coatings, one was chemo-mechanically polished and the other diamond sample was made free standing by wet-chemical etching of the silicon wafer. The coefficient of friction of the MWCVD grown PCD against Al2O3 ball under dry ambient condition was found in the range of 0.29–0.7, but in the presence of simulated body fluid, the COF reduces significantly, in the range of 0.03–0.36. The samples were then characterized by Raman spectroscopy for their quality, by coherence scanning profilometer for surface roughness and by electron microscopy for their microstructural properties. Alumina balls worn out (14.2 × 10−1 mm3) very rapidly with zero wear for diamond ceramic coatings. Since the generation of wear particle is the main problem for load-bearing prosthetic joints, it was concluded that the PCD material can potentially replace existing alumina bio-ceramic for their better tribological properties.

In situ immobilization of Candida antarctica B lipase in polyurethane foam support

Candida antarctica B (CALB) lipase was immobilized using polyurethane (PU) foam as support by confinement method. This can be a promising technique due to the low cost of the support, simple procedure of immobilization and the possibility of using the derivative as catalyst for the food industry reactions. CALB immobilization on PU was performed using 6mL polyol and 4mL isocyanate (60–40%, v/v), with 1mL of enzymatic solution (0.8g enzyme in 5mL distilled water). The immobilization process resulted in a 535% increase in activity for the enzymatic derivative. The enzyme was stable for 360 days at room (10–25°C) and low (2–8°C) temperatures, for 300 days at 40 and 60°C and for 150 days at 80°C in wet ambient conditions. The synthesis of geranyl propionate and ethyl oleate catalyzed by the immobilized derivative presented conversions of around 97 and 83%, respectively. The immobilized CALB in PU was reused consecutively different behavior occurred which stored in dry ambient conditions at different temperatures (room: 10–25°C, refrigeration: 2–8°C and 40°C) resisted 30 cycles, for both forms of storage, keeping more than 87, 95 and 83% of its activity, respectively.