ANALISIS MUTU IKAN PATIN (Pangasius sp.) SALAI DENGAN PEMBERIAN KITOSAN DAN LAMA PENGASAPAN SEBAGAI RANCANGAN LKPD BIOLOGI SMA

The aims to determine the effect of chitosan concentration and smoking time on the quality of smoked catfish (Pangasius sp.) and produce Student Worksheet design. This research was divided into two step, there is experimental step and the Student Worksheet design. At the experimental step, used a factorial Completely Randomized Design (CRD). Factor I is the concentration of chitosan, and factor II is duration of smoking time. This study consisted of 12 treatments with 3 replications so that there were 36 experimental units. Parameters observed were protein content, fat content, water content and organoleptic on appearance, scent, taste and texture. The results showed that the effect of chitosan concentration and smoking time had an effect on treated with 3% chitosan and 3 days of smoking showed the best results, with the total protein content was 35.89%, fat content was 29.72% and water content was 15.27%. Meanwhile, the organoleptic test results of smoked catfish on the aspects of appearance, scent, taste and texture, the best treatment was also found in smoked catfish with 3% chitosan treatment and 3 days of smoking time. The results can be used as a student worksheet design on Food Additives material for class XI high school.

The Frequency and Real-Time Properties of the Microcontroller Implementation of Fractional-Order PID Controller

The paper presents time, frequency, and real-time properties of a fractional-order PID controller (FOPID) implemented at a STM 32 platform. The implementation uses CFE approximation and discrete version of a Grünwald–Letnikov operator (FOBD). For these implementations, experimental step responses and Bode frequency responses were measured. Real-time properties of the approximations are also examined and analyzed. Results of tests show that the use of CFE approximation allows to better keep the soft real-time requirements with an accuracy level a bit worse than when using the FOBD. The presented results can be employed in construction-embedded fractional control systems implemented at platforms with limited resources.

The Ugi-Three Component Reaction and its Variants

More than 60 years have passed since I. Ugi synthesized the first α-amidoamides in one experimental step involving a combination of aldehydes, amines, carboxylic acids and isocyanides, a multicomponent reaction...

Adiabatic Absorption by Absorbent Atomization for Improving Absorption Heat Transformer Performance

Absorption heat transformers (AHTs) are a type of absorption heat pumps that are primarily driven by low-grade (typically waste) heat and produce higher temperature (high-grade) heat. Under the Indus3Es project, a 10 kW LiBr-H2O “Lab Scale” absorption heat transformer was built as a first experimental step toward larger scales. The focus was on the high-pressure vessel (HPV) (absorber and evaporator) design. To enhance performance, the aim was to obtain complete adiabatic absorption prior to the main absorption process accompanied by heat transfer. This maximizes the temperature within the absorber. This is particularly beneficial for absorption heat transformers, compared to chillers, because obtaining an elevated temperature is the objective. To obtain adiabatic absorption, atomizing spray nozzles were used as the liquid absorbent distribution system. This method proved successful; complete adiabatic absorption was obtained before the droplets contacted the absorber heat exchange surfaces. However, the spray nozzles must be supplied with pressurized liquid and are potentially more delicate than alternative liquid distribution systems. Therefore, future work may focus on determining the required atomization level to avoid excessive pressures and nozzle requirements.

UMA PROPOSTA PARA O ENSINO DE LABORATÓRIO DE QUÍMICA ANALÍTICA QUALITATIVA

A PROPOSITION FOR TEACHING LABORATORY OF QUALITATIVE ANALYTICAL CHEMISTRY. Teaching laboratory of qualitative analytical chemistry is still a controversial issue in chemistry courses. However, important researchers and educators in chemistry recognized and highlighted the importance that the contents of this discipline represent in the formation of chemists, once it can provide handling and understanding of microscopic phenomena based on the observation of their macroscopic effects, once such reactions and phenomena are the basis of important instrumental methods of analysis. Thus, a proposal based on a bottom-up approach has been developed, starting with the observation of different reactions of cations in laboratory, followed by a search for the reaction responsible for each resulting phenomenon observed during the experimental step. Then these reactions are related with the separation procedures of each group of cations. Eventually the separation of these groups can also be performed depending on the time available. The proposal has been applied in teaching laboratory of qualitative analytical chemistry at Instituto de Química de São Carlos/USP since 2015, where the discipline is offered duirng 4 hours/week, and a positive feedback regarding the evolution of the methodology and its acceptance by students. Good results were also obtained concerning the appropriation of the contents by the students, using the proposal.

Comparative Study of the Reactivity of the Tungsten Oxides WO2 and WO3 with Beryllium at Temperatures up to 1273 K

Tungsten oxides play a pivotal role in a variety of modern technologies, e.g., switchable glasses, wastewater treatment, and modern gas sensors. Metallic tungsten is used as armor material, for example in gas turbines as well as future fusion power devices. In the first case, oxides are desired as functional materials; while in the second case, oxides can lead to catastrophic failures, so avoiding the oxidation of tungsten is desired. In both cases, it is crucial to understand the reactivity of tungsten oxides with other chemicals. In this study, the different reactivities of tungsten oxides with the highly-oxophilic beryllium are studied and compared. Tungsten-(IV)-oxide and tungsten-(VI)-oxide layers are prepared on a tungsten substrate. In the next step, a thin film of beryllium is evaporated on the samples. In consecutive steps, the sample is heated in steps of 100 K from room temperature (r. t.) to 1273 K. The chemical composition is investigated after each experimental step by high-resolution X-ray photoelectron spectroscopy (XPS) for all involved core levels as well as the valence band. A model is developed to analyze the chemical reactions after each step. In this study, we find that tungsten trioxide was already reduced by beryllium at r. t. and started to react to form the ternary compounds BeWO3 and BeWO4 at temperatures starting from 673 K. However, tungsten dioxide is resistant to reduction at temperatures of up to 1173 K. In conclusion, we find WO2 to be much more chemically resistant to the reduction agent Be than WO3.

Comparative Study of the Reactivity of the Tungsten Oxides WO2 and WO3 with Beryllium at Temperatures up to 1273 K

Tungsten oxides play a pivotal role in a variety of modern technologies e.g., switchable glasses, wastewater treatment, and modern gas sensors. Metallic tungsten is used as armor material, for e.g., gas turbines as well as future fusion power devices. In the first case, oxides are desired as functional materials, while in the second case, oxides can lead to catastrophic failures, so avoiding the oxidation of tungsten is desired. In both cases, it is crucial to understand the reactivity of tungsten oxides with other chemicals. In this study, the different reactivities of tungsten oxides with the highly-oxophilic beryllium are studied and compared. Tungsten-(IV)-oxide and tungsten-(VI)-oxide layers are prepared on a tungsten substrate. In the next step, a thin film of beryllium is evaporated on the samples. In consecutive steps, the sample is heated in steps of 100 K from r. t. to 1273 K. The chemical composition is investigated after each experimental step by high-resolution X-ray photoelectron spectroscopy (XPS) of all involved core levels as well as the valence band. A model is developed to analyze the chemical reactions after each step. In this study, we find that tungsten trioxide was already reduced by beryllium at r. t. and started to react to form the ternary compounds BeWO3 and BeWO4 at temperatures starting from 673 K. However, tungsten dioxide is resistant to reduction at temperatures of up to 1173 K. In conclusion, we find WO2 to be much more chemically resistant to the reduction agent Be than WO3.

Comparative Study of The Reactivity of the Tungsten Oxides WO2 And WO3 With Beryllium at Temperatures up to 1273 K

Tungsten oxides play a pivotal role in a variety of modern devices e.g. switchable glasses, wastewater treatment and modern gas sensors and metallic tungsten is used as armour material for e.g. gas turbines and future fusion power devices. In the first case you want to keep the oxide as functional material, while in the second case oxides can lead to catastrophic failures and you want avoid oxidation of tungsten. In both cases it is crucial to understand the stability of the tungsten oxides against chemicals. In this study the different reactivity of tungsten oxides towards the highly oxophilic beryllium is studied and compared. Tungsten--(IV)--oxide and tungsten--(VI)--oxide layers are prepared on a tungsten substrate. In the next step a thin film of beryllium is evaporated on the samples. In consecutive steps the sample is heated in steps of 100 K from r.t. to 1273 K. The chemical composition is investigated after each experimental step by high resolution X-ray photoelectron spectroscopy (XPS) of all involved core levels as well as the valence bands. A model is developed to analyse the chemical reactions after each step. In this study, we found the tungsten trioxid is reduced already by beryllium at r.t. and starts to react towards the ternary compounds BeWO_3 and BeWO_4 at temperatures starting from 673 K. However, the tungsten dioxide sample is reduction resistant to tempartures up to 1173 K. In conclusion, we found the WO_2 surface to be much more chemical resistant towards the reduction agent Be than WO_3.