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Parameters (mean and covariance matrix) estimation is often a problem of interest since it provides information about the location and variation of the data and correlation between features and can be used for hypothesis testing, principle component analysis, etc. However, it is also common that values in some features of a dataset are missing. A popular way to deal with this problem is to use an Expectation-Maximization algorithm or to impute the missing values and then estimate the parameters based on imputed data. However, the first approach is a local optimization approach that may not converge under a fixed number of iterations. The second one, a two-step approach of imputation and analysis, is computationally inefficient. Therefore, we follow the recent trends of estimating the parameters directly from the data and propose PMF (Parameter estimation for Missing data in some Features) to deal with the aforementioned problems. The experiments show that our approach achieves better performance than other methods under comparison in performance and speed. Moreover, our estimates are asymptotic.

The linear viscoelastic (LVE) characterisation of asphalt mixtures in time domain is generally performed at temperature lower than 30°C to prevent the effect of permanent deformation. Although LVE ...

Understanding the Heat transfer performance of refrigerant for convective boiling in horizontal microfin tube and smooth tube is place an importance role on the designing of evaporator, the main equipment on refrigeration system. Reviewing the general concept especially the theory of boiling in the tube, the formation of the flow pattern map, the calculating procedure for heat transfer coefficient and pressure drop during boiling process of refrigerant in microfin tube. Besides, a typical example will be presented more detail in step by step to define the heat transfer coefficient and pressure drop for one working condition to estimate the data results without doing experiments.

Environmental concerns are forcing the replacement of commonly used refrigerants, and finding new fluids is a top priority. Soon the R134a will be banned, and the hydro-fluoro-olefin (HFO) R1234ze(E) has been indicated as an alternative due to its smaller global warming potential (GWP) and shorter atmospheric lifetime. Nevertheless, for an optimal replacement, its thermo-fluid-dynamic characteristics have to be assessed. Flow boiling experiments (saturation temperature Tsat = 5 °C, mass flux G = 65 ÷ 222 kg·m−2·s−1, mean quality xm = 0.15 ÷ 0.95, quality changes ∆x = 0.06 ÷ 0.6) inside a microfin tube were performed to compare the pressure drop per unit length and the heat transfer coefficient provided by the two fluids. The results were benchmarked for some correlations. In commonly adopted operating conditions, the two fluids show a very similar behavior, while benchmark showed that some correlations are available to properly predict the pressure drop for both fluids. However, only one is satisfactory for the heat transfer coefficient. In conclusion, R1234ze(E) proved to be a suitable drop-in replacement for the R134a, whereas further efforts are recommended to refine and adapt the available predictive models.

Background: Peripheral facial nerve palsy is a relatively common disease in clinical practice, the major cause is cold which corresponding to Wind Cold clinical forms according to traditional medicine. The disease is divided into 4 stages, however the level of response to treatment in the later stages is often lower than in the acute phase. This study used acupuncture that were recommended combine with traditional medicine to treat this desease in subacute and recovering stage to bring about effective treatment as well as to return to normal face soon and it does not affect the patient’s quality life and aesthetics. Objectives: Evaluate the effect of treatment and quality of life of peripheral facial nerve palsy Wind-Cold clinical forms in subacute and recovering stage by electroacupunture combined with traditional medicine. Materials and method: Intervention studies, comparisons before and after treatment in 30 patients with definite diagnosis ofperipheral facial nerve palsy Wind-Cold clinical forms in subacute and recovering stage, from January to December 2018 in Thua Thien Hue Traditional Medicine Hospital. Result: The rate of complete recovery after treatment accounted for 6.7% (grade I). There are 10 cases of normal recovery of facial muscles function (normal 75-100%), accounting for 33.3%. About quality of life, after treatment, the score increased significantly, the difference was statistically significant (p < 0.05). Conclusion: The therapeutic effect of electroacupunturecombined with traditional medicine for disease peripheral facial nerve palsy Wind-Cold clinical forms in subacute and recovering stage is not high. Quality of life after treatment has improved better. Key words: Peripheral facial nerve palsy, Wind Cold, subacute stage, recovering stage, electroacupunture, traditional medicine

A study of drying parameters on the drying process of Pisum Sativum bean was carried out. The effects of drying temperature of moisture air from 40°C to 80°C on the drying time and on the drying kinetics were demonstrated not only on conventional electric dryers but also on heat pump dryers. Besides, checking the steady operation of the heat pump dryer was also considered. The results show that, when temperature rises, the shorter time and the faster removal of moisture content can be obtained for both dryer systems. Drying in an electric heater at 80°C took only 1 hour 45 minutes, but the broken skin of pea seeds happened. The comparison of heat pump dryer and electric dryer was presented with the shorter drying time on heat pump than electric dryer as a result of removing water vapor from moisture air at the evaporator of heat pump, it led to the reduction of specific humidity of air entering the drying chamber. And the last impressive result which can be seen is that the drying rate of a heat pump is higher than an electric dryer at the same drying temperatures beside the energy consumption of electric dryer is 2.76 times as much as that of heat pump dryer.

In order to prevent distresses in asphalt pavement, the analysis of pavement structure should be as close as possible to its real behavior. However, in actual standard for designing asphalt pavement, viscoelastic behavior of asphalt mixtures and effects of moving vehicles are still not considered. In this paper, the authors aim at applying an analytical approach for analyzing the linear viscoelastic behavior of asphalt pavements comprised of conventional and high modulus asphalt concrete caused by a moving loading. It is shown that the effects of moving load give rise to an increase in tensile stress at the pavement surface and at the bottom of asphalt layers, which can be a reason for premature cracks in flexible pavement. The results also show that the use of high modulus asphalt concrete layers gives rise to a significant reduction of tensile stress and strain at the pavement surface as well as at the bottom of asphalt layer.

The analysis of extracting potable water from the humid ambient air has been done by using the model of vapor-compression refrigeration (VCR) system for the case study in Vietnam. The temperature and relative humidity of moist air in Danang province in Vietnam were recorded for a whole year. The typical day in each month of year with detailed values of temperature and relative humidity for 24 hours were presented and used to identify the production of water from the air. The results show that, the temperature at the outlet of air stream throughout evaporator of VCR system is about 13°C in which the energy consumption to produce 1 liter of water is lowest. Besides, the electricity consumption cost in Vietnam varies in a day with various tariffs: at the peak load, medium load and low load, depends on the time of the day. The production price for one liter of water is also considered and working plans are proposed for the system by the time of the day.

According to statistics from the Ho Chi Minh Energy Saving Center, the electricity costs of the air conditioning system for office buildings are about 70% of the electricity costs. There are many solutions that have been proposed to reduce the operating costs of the air conditioning systems, this article discusses a method of accumulating cold to reduce the cost of electricity for the air conditioning system of an office building.

This study analyses the performance of heat transfer process which occurs in the convective boiling of Hydro fluoro Olefin (HFO) refrigerant, R1234yf, in horizontal tube. Heat transfer and pressure drop of R1234yf are analyzed and computed at the same working conditions on the same size of outer diameter of tube do = 9.52 mm with difference of inner surface, one is a smooth surface and microfin for other. The flow pattern maps were built at 5°C saturation temperature with 8.62 kW/m2of heat flux, it is presented that flow pattern of helix flow occurs at very low mass flux and low quality, while at that condition on smooth tube the flow is still stratified wavy flow. The comparison of heat transfer performance between microfin and smooth tube would be evaluated on enhancement factorE, penalty factorPand efficiency indexI. With the mass flux on the rangeG= 111 -- 333 kg/m2s for 5°C boiling temperature, the results show that, average value ofEis 2.18; 1.45 ofPand 1.54 ofI. One more impressing thing is that, at the quality “x” larger than 0.8, the dryout phenomenon takes place on smooth tubes while microfin tubes do not have this phenomenon.

In recent decades, manufacturing outsourcing has become a strategic trend in industry as manufacturing organizations desire to reduce costs and focus on core competencies. Organizations have a range of location options for outsourcing to select, such as, local, nearshore and offshore. Lower labor cost is considered as a dominant factor for many companies to choose outsourcing and foreign vendors in particular. However, higher transaction costs always are considers as one the most significant disadvantages of outsourcing especially in case of offshore and nearshore. Meanwhile, manufacturing process standardization, which is considered as a way to achieve, transparency and uniformity of manufacturing activities, resulting in reducing transaction costs. But up to now, there are a few studies of the impact of manufacturing process standardization on outsourcing decisions. So in this paper, we propose a framework including three factors, the degree of product or manufacturing process standardization, transaction costs and labor cost, to help the supply chain executives make optimal outsourcing location choice. Results show that, the higher the the degree of process standardization is, the further focal firms can outsource their production.

An experimental facility was designed to measure pressure drop and heat transfer coefficient during flow boiling of azeotropic refrigerants in horizontal tubes. The apparatus is made of the refrigerant circuit, including the test section; the water circuit, to provide the power for evaporation; the glycol-water circuit, to fix the refrigerant pressure. The test section is a counterflow tube-in-tube heat exchanger (refrigerant inside, water outside). Plant assessment involved the measurement of pressure drop and heat transfer during R134a flow boiling in a smooth tube (outer diameter 9.56mm, inner diameter 8.92mm). Such a case study is a benchmark for the availability of a wide experimental database in the literature, which has been also summarized in many correlations. Then further tests involved a microfin tube. The experimental conditions were: evaporation temperature, 5°C; mass flux, 111÷333kg/m2s; average quality, 0.15÷0.93; heat flux, 8.8kW/m2 and 17.6kW/m2. The uncertainty affecting the pressure drop and the heat transfer coefficient resulted lower than 1% and 5% respectively. The comparison with the literature shows satisfactory agreement with the major findings and enables using the data for the assessment of the existing models to predict both the pressure drop and the heat transfer coefficient.