Transmission Rate Values Research Articles

Dynamics and control of delayed rumor propagation through social networks.

Investigation of rumor spread dynamics and its control in social networking sites (SNS) has become important as it may cause some serious negative effects on our society. Here we aim to study the rumor spread mechanism and the influential factors using epidemic like model. We have divided the total population into three groups, namely, ignorant, spreader and aware. We have used delay differential equations to describe the dynamics of rumor spread process and studied the stability of the steady-state solutions using the threshold value of influence which is analogous to the basic reproduction number in disease model. Global stability of rumor prevailing state has been proved by using Lyapunov function. An optimal control system is set up using media awareness campaign to minimize the spreader population and the corresponding cost. Hopf bifurcation analyses with respect to time delay and the transmission rate of rumors are discussed here both analytically and numerically. Moreover, we have derived the stability region of the system corresponding to change of transmission rate and delay values.

Flexible PDMS/Al2O3 Nanolaminates for the Encapsulation of Blue OLEDs

AbstractIn this work, the polydimethylsiloxane (PDMS)/Al2O3 nanolaminates with optimized sublayer thickness and interfaces have been developed to protect the organic light‐emitting didoes (OLEDs) from the erosion of the moisture in the ambient. The O2 plasma pretreatment is used to tune the wettability of the ultrathin PDMS sublayers with nanoscale thickness, and the distinct interfaces between the Al2O3 and PDMS sublayers are obtained. The electrical calcium test is exploited to evaluate the barrier properties of the encapsulation nanolayers, and the water vapor transmission rate (WVTR) value of the 2.5 PDMS/Al2O3 dyads can reach the range of ≈10−5 g m−2 day−1. The mechanical stability of the nanolaminates is further improved by introducing the top epoxy layer, which helps move the neutral axis (NA) to the center of the barrier, and the applied external strain decreases significantly. Compared with the sample without the epoxy layer, a slighter increase of the WVTR value of the multilayered encapsulation films with optimized NA position is obtained. Furthermore, the operational lifetime of blue OLEDs encapsulated with the multilayered encapsulation films improves from 6 to more than 370 h, which shows significantly improved stability and reliability.

Functionalization of carrageenan based edible film using Aloe vera for improved lipid oxidative and microbial stability of frozen dairy products

The aim of the present study was to standardize, characterize and evaluate the efficacy of an A. vera-based edible film developed for improved microbial and lipid oxidative stability of frozen dairy products. Kulfi, a popular Indian ice cream, was used as a model system. The film was standardized using different levels of carrageenan (1.0, 1.5 and 2.0%), glycerol (12, 14 and 18%) and A. vera extract (9, 12 and 15%). Addition of A. vera increased the thickness (mm) and density (g/ml) whereas decreased the water vapor transmission rate (mg/m2t), transmittance (%) and lightness (L*) values of the film. A. vera extract increased the antioxidant capacity of the film and imparted antimicrobial properties against E. coli. The film containing optimum level of carrageenan (1.5%), glycerol (14%) and A. vera (15%) showed highest antioxidant and antimicrobial potential. Products packaged in AE (15%) film containing 15% A. vera extract showed significantly (p < 0.05) lower values for microbial counts (total plate, psychrophilic and yeast/mould, log10 cfu/g), free fatty acids (% oleic acid) and TBARS (mg malondialdehyde/kg) compared to control samples during six-month storage at −18 ± 1 °C. The developed film significantly improved the microbial and lipid oxidative stability of kulfi during storage and can be commercially used for improving storage stability of frozen dairy products. A. vera-based products can have a special health importance during pandemic of SARS-CoV-2 due to its strong immune boosting and antiviral properties.

Mathematical modeling of COVID-19 in India and its states with optimal control.

A pandemic is an epidemic spread over a huge geographical area. COVID-19 is 5hbox {th} such pandemic documented after 1918 flu pandemic. In this work, we frame a mathematical epidemic model taking inspiration from the classic SIR model and develop a compartmental model with ten compartments to study the coronavirus dynamics in India and three of its most affected states, namely, Maharashtra, Karnataka, and Tamil Nadu, with inclusion of factors related to face mask efficacy, contact tracing, and testing along with quarantine and isolation. We fit the developed model and estimate optimum values of disease transmission rate, detection rate of undetected asymptomatic, and the same of undetected symptomatic. A sensitivity analysis is presented stressing on the importance of higher face mask usage, rapid testing, and contact tracing for curbing the disease spread. An optimal control analysis is performed with two control parameters to study the increase and decrease of the infected population with and without control. This study suggests that improved and rapid testing will help in identifying more infectives, thereby contributing in the decline of disease transmission rate. Optimal control analysis results on stressing on the importance of abiding by strict usage of face mask and social distancing for drastic decrease in number of infections. Time series behaviour of the symptomatic, asymptomatic, and hospitalized population is studied for a range of parameters, resulting in thorough understanding of significance of different parameters.

Films Based on Mater-Bi® Compatibilized with Pine Resin Derivatives: Optical, Barrier, and Disintegration Properties

Mater-Bi® NF866 (MB) was blended with gum rosin and two pentaerythritol esters of gum rosin (labeled as LF and UT), as additives, to produce biobased and compostable films for food packaging or agricultural mulch films. The films were prepared by blending MB with 5, 10, and 15 wt.% of each additive. The obtained films were characterized by optical, colorimetric, wettability, and oxygen barrier properties. Moreover, the additives and the MB-based films were disintegrated under composting conditions and the effect of each additive on the biodegradation rate was studied. All films were homogeneous and optically transparent. The color of the films tended to yellow tones due to the addition of pine resin derivatives. All the formulated films presented a complete UV-transmittance blocking effect in the UVA and UVB region, and those with 5 wt.% of pine resin derivatives increased the MB hydrophobicity. Low amounts of resins tend to maintain the oxygen transmission rate (OTR) values of the neat MB, due to its good solubilizing and compatibilizing effects. The disintegration under composting conditions test revealed that gum rosin completely disintegrates in about 90 days, while UT degrades 80% and LF degrades 5%, over 180 days of incubation. As expected, the same tendency was obtained for the disintegration of the studied films, although Mater-Bi® reach 28% of disintegrability over the 180 days of the composting test.

Preparation and Characterization of Polystyrene Hybrid Composites Reinforced with 2D and 3D Inorganic Fillers

Polystyrene (PS)/silicate composites were prepared with the addition of two organoclays (orgMMT and orgZenith) and two mesoporous silicas (SBA-15 and MCF) via (i) solution casting and (ii) melt compounding methods. X-ray diffraction (XRD) analysis evidenced an intercalated structure for PS/organoclay nanocomposites. Thermogravimetric analysis indicated improvement in the thermal stability of PS-nanocomposites compared to the pristine polymer. This enhancement was more prevalent for the nanocomposites prepared with a lab-made organoclay (orgZenith). Tensile measurement results indicated that elastic modulus increment was more prevalent (up to 50%) for microcomposites prepared using mesoporous silicas as filler. Organoclay addition led to a decrease in oxygen transmission rate (OTR) values. This decrement reached up to 50% for high organoclay content films in comparison to pristine PS film. Decrement above 80% was measured for microcomposites with mesoporous silicas and 5 wt% filler content obtained via melt compounding.

Structure-Gas Barrier Property Relationship in a Novel Polyimide Containing Naphthalene and Amide Groups: Evaluation by Experiments and Simulations.

In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized. Results show that the NAPPI exhibits superior barrier properties with extremely low water vapor and oxygen transmission rate values of 0.14 g·m−2·day−1 and 0.04 cm3·m−2·day−1, respectively. In addition, the NAPPI presents outstanding mechanical properties and thermal stability as well. This article attempts to explore the relationship between NAPPI structure and barrier properties by combining experiment and simulation. Studies on positron annihilation lifetime spectroscopy, Wide angle X-ray diffractograms and molecular dynamics simulations prove that the NAPPI has smaller interplanar spacing and higher chain regularity. In addition, the strong chain rigidity and interchain cohesion of NAPPI due to the presence of the rigid naphthalene ring and a large number of hydrogen bond interactions formed by amide groups result in compact chain packing and smaller free volume, which reduces the solubility and diffusibility of small molecules in the matrix. In general, the simulation results are consistent with the experimental results, which are important for understanding the barrier mechanism of NAPPI.

Structural and gas barrier properties of hydrogenated silicon nitride thin films prepared by roll-to-roll microwave plasma-enhanced chemical vapor deposition

Hydrogenated amorphous silicon nitride films (a-SiNx:H) have attracted attention as barrier layers to prevent the diffusion of water vapor and other gases into electronic devices. Herein, the chemical composition and physical properties of a-SiNx:H films prepared using a roll-to-roll microwave plasma-enhanced chemical vapor deposition (MW-PECVD) process at low temperatures and variable NH3/SiH4 flow-rate ratios (R) were analyzed. This study was performed to identify the factors affecting the gas permeability of these films as represented by their water vapor transmission rate (WVTR) values. The films fabricated under SiH4-rich conditions (R < 2.75) were oxidized during storage in air to produce silicon oxynitride (SiOxNy), whose properties differed from those of silicon nitride (SiNx). It was found that gas barrier properties were affected by both the film and the Si–H bond densities. Under optimal conditions, the WVTR of a 100-nm-thick SiNx single layer was as low as 7 × 10−3 g m−2 d−1, and the Si–H bond density was 6.71 × 1021 cm−3. The compressive and tensile stresses of the SiNx:H films depended on the values of R, with excellent mechanical stability and moisture barrier properties having been obtained for R = 2.75–3.00.

COVID-19 Mathematical Epidemic Model for Impact Analysis of Large Scale Social Restriction: The Case Study of Indonesia

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2. There have been 218,382 confirmed cases of COVID-19, including 8,723 deaths in Indonesia till September 15, 2020. To fight Covid-19, the Indonesian Government modified the lockdown policy to become a large-scale social restriction (LSSR) according to the pandemic level in each region. The LSSR was implemented in DKI Jakarta on April 10, 2020, the epicenter of the Covid-19 outbreak in Indonesia. In this article, we propose the Susceptible-Infected-Hospitalized-Recovered (SIHR) epidemic model for impact analysis of LSSR on epidemic conditions and predict the long-term dynamic COVID-19 in Indonesia. This study extends the SIR model by adding a hospitalized compartment. Finally, we analyze the results of our mathematical model, estimate the model of essential parameters, and predict the disease by considering the real Indonesian cases from March 2 to September 6, 2020. Based on the result, LSSR has a good enough impact on solving the pandemic in Indonesia. One of the factors is because there is a significant difference in transmission rate (β) values. The new normal transmission rate is 75% higher than the LSSR’s.

Estimating Unreported COVID-19 Cases with a Time-Varying SIR Regression Model

Background: Potential unreported infection might impair and mislead policymaking for COVID-19, and the contemporary spread of COVID-19 varies in different counties of the United States. It is necessary to estimate the cases that might be underestimated based on county-level data, to take better countermeasures against COVID-19. We suggested taking time-varying Susceptible-Infected-Recovered (SIR) models with unreported infection rates (UIR) to estimate factual COVID-19 cases in the United States. Methods: Both the SIR model integrated with unreported infection rates (SIRu) of fixed-time effect and SIRu with time-varying parameters (tvSIRu) were applied to estimate and compare the values of transmission rate (TR), UIR, and infection fatality rate (IFR) based on US county-level COVID-19 data. Results: Based on the US county-level COVID-19 data from 22 January (T1) to 20 August (T212) in 2020, SIRu was first tested and verified by Ordinary Least Squares (OLS) regression. Further regression of SIRu at the county-level showed that the average values of TR, UIR, and IFR were 0.034%, 19.5%, and 0.51% respectively. The ranges of TR, UIR, and IFR for all states ranged from 0.007–0.157 (mean = 0.048), 7.31–185.6 (mean = 38.89), and 0.04–2.22% (mean = 0.22%). Among the time-varying TR equations, the power function showed better fitness, which indicated a decline in TR decreasing from 227.58 (T1) to 0.022 (T212). The general equation of tvSIRu showed that both the UIR and IFR were gradually increasing, wherein, the estimated value of UIR was 9.1 (95%CI 5.7–14.0) and IFR was 0.70% (95%CI 0.52–0.95%) at T212. Interpretation: Despite the declining trend in TR and IFR, the UIR of COVID-19 in the United States is still on the rise, which, it was assumed would decrease with sufficient tests or improved countersues. The US medical system might be largely affected by severe cases amidst a rapid spread of COVID-19.

Performance Analysis of Transmission Rate and Decoding Rate Using Minimum Energy Channel Codes for Nanoscale Wireless Communication

An energy efficient communication system is required for the improvement of nanoscale wireless communication. In this paper, we defined minimum energy coding scheme (MEC) to achieve energy efficiency in wireless nanosensor network. MEC maintains the desire code distance to provide reliability and better decoding probability, while requiring less energy to transmit bits of information. We proposed a relationship between transmission rate and decoding rate which is significant for minimum energy channel codes in nanoscale wireless communication. We investigated the performance evaluation of code length limited and energy limited transmission rates on the source cardinality which ensures that for any value of code distance, code length limited transmission rate will be decreased in regard to increasing the value of source cardinality and vice versa for energy limited transmission rate. We studied the optimum value of transmission rate and decoding rate which confirms that if the number of carriers is increased n times, then the optimum transmission and decoding rate would also be increased n times. We also studied the performance evaluation of code distance which is inversely propotional to transmission distance and correct decoding probability. Further, we examined the dependance of average energy per bit which is proportional to symbol duration and bandwidth. On the contrary, spectral efficiency is inversely proportional to symbol duration. We strongly believe that our proposed relationship between transmission rate and decoding rate accompanied by the performance evaluation of various parameters will improve the nanoscale wireless communication system.

Individual Behaviors and COVID-19 Lockdown Exit Strategy: A Mid-Term Multidimensional Bio-economic Modeling Approach.

As of mid-2020, eradicating COVID-19 seems not to be an option, at least in the short term. The challenge for policy makers consists of implementing a suitable approach to contain the outbreak and limit extra deaths without exhausting healthcare forces while mitigating the impact on the country's economy and on individuals' well-being. To better describe the trade-off between the economic, societal and public health dimensions, we developed an integrated bioeconomic optimization approach. We built a discrete age-structured model considering three main populations (youth, adults and seniors) and 8 socio-professional characteristics for the adults. Fifteen lockdown exit strategies were simulated for several options: abrupt or progressive (4 or 8 weeks) lockdown lift followed by total definitive transitory final unlocking. Three values of transmission rate (Tr) were considered to represent individuals' barrier gesture compliance. Optimization under constraint to find the best combination of scenarios and options was performed on the minimal total cost for production losses due to contracted activities and hospitalization in the short and mid-term, with 3 criteria: mortality, person-days locked and hospital saturation. The results clearly show little difference between the scenarios based on the economic impact or the 3 criteria. This means that policy makers should focus on individuals' behaviors (represented by the Tr value) more than on trying to optimize the lockdown strategy (defining who is unlocked and who is locked). For a given Tr, the choices of scenarios permit the management of the hospital saturation level with regard to both its intensity and its duration, which remains a key point for public health. The results highlight the need for behavioral or experimental economics to address COVID-19 issues through a better understanding of individual behavior motivations and the identification of ways to improve biosecurity compliance.

Persistence and extinction of a stochastic SIS epidemic model with regime switching and Lévy jumps

This paper is devoted to a stochastic regime-switching susceptible-infected-susceptible epidemic model with nonlinear incidence rate and Levy jumps. A threshold \begin{document}$ \lambda $\end{document} in terms of the invariant measure, different from the usual basic reproduction number, is obtained to completely determine the extinction and prevalence of the disease: if \begin{document}$ \lambda>0 $\end{document} , the disease is persistent and there is a stationary distribution; if \begin{document}$ \lambda , the disease goes to extinction and the susceptible population converges weakly to a boundary distribution. Moreover, some numerical simulations are performed to illustrate our theoretical results. It is very interesting to notice that random fluctuations (including the white noise and Levy noise) acting the infected individuals can prevent the outbreak of disease, that the disease of a regime-switching model may have the opportunity to persist eventually even if it is extinct in one regime, and that the prevalence of the disease can also be controlled by reducing the value of transmission rate of disease.

Forward and Inverse Analyses of Two-Dimensional Eccentric Annular Fins for Space-Restriction Circumstances

Heat transfer under space restriction is a challenging task in many energy systems due to unavoidable design constraints. For such conditions, the use of regular fin shapes cannot be possible, and eccentric geometry becomes a necessity. In this work, an optimization technique based on the inverse analysis using the differential evolution (DE) has been proposed to identify the dimensions of two-dimensional eccentric annular disk fins. For maximizing the rate of energy transport under a prescribed volume, DE search is first used in the present paper to discover numerous combinations of critical geometrical variables satisfying a constrained volume. Thereafter, all parameters relating to the energy transport are obtained from a direct analysis aided by a semi-analytical technique. It is envisaged from the current inverse analysis that under a given volume of the fin, although the same maximum value of heat transmission rate can be acquired with multiple combinations of fin dimensions, there is a sufficient scope to minimize the fin surface area. Here, the optimized temperature contour acts as a significant cause in selecting the unique combination of the optimized fin geometry. Finally, the role of fin thickness is found more influential to control the rate of energy exchange.

Enhancing the Oxygen Barrier Properties of Nanocellulose at High Humidity: Numerical and Experimental Assessment

Films formed from cellulose nanofibrils (CNFs) are known to be good barrier materials against oxygen, but they lose this feature once placed in humid conditions. To tackle this issue, we applied an optimized pressing condition under elevated temperature to increase the films’ density and improve their barrier performance. Furthermore, a water barrier coating was employed on the surfaces to control the moisture uptake at high relative humidity (RH). Neat self-standing films of CNF with the basis weight of 70 g/m2 were made through a filtration technique and pressed for 1 hour at 130 °C. The resulting nanostructures were covered on both sides using a water-borne barrier layer. Hot-pressing resulted in a significant reduction in oxygen transmission rate (OTR) values, from 516.7 to 3.6 (cm3/(m2·day)) and to some degree, helped preserve the reduced oxygen transmission at high relative humidity. Introducing 35 g/m2 of latex coating layer on both sides limited the films’ swelling at 90% RH for about 4 h and maintained the OTR at the same level. A finite element model was used to predict the dynamic uptake of water into the systems. The model was found to over-predict the rate of water uptake for uncoated samples but gave the correct order of magnitude results for samples that were coated. The obtained data confirmed the positive effect of hot-pressing combined with coating to produce a film with low oxygen transmission rate and potential to maintain its oxygen barrier feature at high relative humidity.

Estimating Unreported COVID-19 Cases in the United States Based on Time-Varying SIR Model

Background The potential unreported infection may impair and mislead policymaking，and the contemporary spread of COVID-19 varies in different counties of the United States. It is necessary to estimate the cases that may be underestimated based on county-level data to take better countermeasures against COVID-19. We suggested taking time-varying SIR models with unreported infection rates (UIR)to estimate the factual COVID-19 cases in the United States.Methods SIR integrated with unreported infection rates (SIRu) of fixed time effect and SIR with time-varying parameters (tvSIRu)were applied to estimate and compare the value of transmission rate(TR), UIR, and infection fatality rate (IFR) based on US county-level COVID-19 data. Results Based on US county-level COVID-19 data from January 22 (T1) to August 20 (T212) in 2020, SIRu was first tested and verified by a general OLS regression. The further regression of SIRu at the country-level showed that the average values of TR, UIR, and IFR were 0.034,19.5, 0.51% respectively. The range of IR, UIR, IFR of all states ranged were 0.007-0.157 (mean=0.048) ,7.31-185.6 (mean=38.89), and 0.04%-2.22% (mean=0.22%). Among time-varying transmission rate equations, the power function showed better fitness, which indicated a decline in TR decreasing from 227.58 (T1) to 0.022 (T212). The general equation of tvSIRu showed that both the UIR and IFR were gradually increasing, wherein, the UIR has an estimate of 9.1(95%CI = 5.7-14.0), and IFR was 0.70% (0.52%-0.95%) at T212.Interpretation Despite the decline in TR and IFR, the UIR of the United States is still on the rise, which had been supposed to decrease with sufficient tests or improved countersues. The US medical system may be largely affected by severe cases in the rapid spread of COVDI-19.

Effect of plasma carrier gas on the moisture barrier properties of plasma-enhanced chemical vapor deposited (PECVD) polyorganosiloxane thin film

A polyorganosiloxane thin film was deposited on an optically transparent poly(ethylene 2,6-naphthalate) (PEN) film using plasma-enhanced chemical vapor deposition (PECVD) at room temperature to improve the moisture barrier property of the PEN film. In the PECVD process, hexamethyldisiloxane (HMDSO) was used as the monomer. Argon or oxygen and their mixture gases were used as the plasma carrier gas. Poly(HMDSO) thin film was successfully deposited through plasma-induced radical polymerization reaction on the surface of PEN film. It was observed that the mixture ratio of argon-oxygen carrier gas significantly affected the surface and the moisture barrier properties of the resulting poly(HMDSO) film. Chemical structures of the poly(HMDSO) were confirmed using FT-IR analysis. Surface properties of the poly(HMDSO) thin film were investigated by water contact angle measurement and atomic force microscopy (AFM). Water vapor transmission rate (WVTR) value was obtained by an electrical calcium test (Ca test) at 85 °C and 85% relative humidity condition. It was confirmed that the poly(HMDSO) thin film exhibited excellent water vapor barrier capability. WVTR value of the PEN film coated with poly(HMDSO) deposited with a mixture of argon and oxygen (Ar: O2 = 2: 8) was 5.09 g/m2-day, which is much lower than 18.4 g/m2-day of a bare PEN film.

Characteristics of Edible Films Based on Corn Starch and Protein Isolates from Liquid Waste Extraction of Tofu Processing Industry

One factor contributing to the environment's waste is industrial activity both large and small scale. During this time, the waste collection is done by dumping it into a ditch and flowing it into the river, thus worsening environmental sanitation. This study aims to analyze the character of edible films of corn starch with protein isolates from the extraction of tofu processing industry wastewater. Samples were analyzed to determine the tensile strength and elongation of the resulting film by varying the amount of protein isolates, 0%, 3%, 5%, 7% and 9%. The protein extraction process was carried out by centrifugation, while the water vapor transmission test was by the saucer method, while the identification of functional groups was through FTIR analysis. The results showed that the highest mechanical properties were obtained in the variation of 5% protein isolates with a value of 52.16 MPa and elongation of 38.4%. For water vapor transmission rate (WVTR), film comparisons were made with 5% variation of protein isolates and 0% protein isolates. Films with 5% protein isolates have a smaller water absorption of 0.56%, than films with 0% of 0.66%. The value of water vapor transmission rate shows a very significant ratio, at 5% protein isolate of water vapor transmission at 0.00176 g/m2/day, much smaller than 0% protein isolate at 0.00864 g/m2/day. IR spectra showed the presence of amide groups I and II on the results of the analysis of protein isolates. While the globular structure of proteins is shown by the absorption of wave numbers 1667 and 1650 cm-1.

3D Photoinduced Spatiotemporal Resolution of Cellulose-Based Hydrogels for Fabrication of Biomedical Devices.

Rational spatiotemporal irradiation of cellulose-based hydrogels (carboxymethylcellulose (CMC), citric acid, and riboflavin) using a laser diode stereolithography 3D printer obtained architectures referred to as photodegradation addressable hydrogels (PAHs). Under irradiation, these PAHs engage in an unprecedented spatially resolved zonal swelling illustrating marked but controllable changes in swelling and thickness while concomitantly obtaining improved oxygen transmission rate values by 5 times. XPS, carboxyl content, and swelling data comparisons of hydrogel formulations show that photodegradation and ablation of the material occur, where hydroxyl sites of CMC are converted to aldehydes and ketones. XRD data show that the total number of crystalline aggregates in the material are lowered after photoablation. The spatially tuned (photoablated) hydrogel films can thus be shaped into a lens form. The energy required for the lens tuning process can be lowered up to 30 times by incorporation of riboflavin in the films. The method demonstrated here enables the processing of a material that is difficult to be machined or cast by popular contact lens making methods.

Active Starch/PVA Composite Films Containing &lt;i&gt;Syzygium oleana&lt;/i&gt; for Ammonia Vapor Colorimetric Indicators

Ammonia is one of the compounds released during the food spoilage process, so a device that can detect ammonia can be used as an indicator of food spoilage. This article reports on the preparation and characteristics of Starch/PVA composite films with Syzygium oleana as indicator films to detect ammonia vapor. The indicator was made by first preparing the starch / PVA composite films by casting method and then the films were dipped in Syzygium oleana extract. These films were characterized by using a UV-Vis spectrophotometer, Fourier Transformed Infra-Red Spectrophotometer and tested for mechanical properties such as tensile strength and elongation, and the water vapor transmission rate (WVT). The results showed that the addition of PVA reduced the absorbance value in the UV and visible area, the value of the water vapor transmission rate and the tensile strength but the elongation value of the film on the other hand rose. The indicator films can detect ammonia which was marked by its color change from red to blue. For further application, it can be used as a smart packaging label that can detect food freshness.