Comparison of the Performance of the Two Dry Block Furnaces for RTC158B and Const660

The dry block temperature calibrator uses air as the calibration medium with small volume and light weight, and therefore is widely applied in field calibration work. With the improvement and vigorous development of the technology of domestic instruments, the technology of domestic dry body furnace is also developing rapidly. Whether the performance of domestic dry block temperature calibrator is better than the foreign instruments, this question is not very clear yet. Therefore, this study focuses on the comparative analysis of the performance parameters of the two dry-type temperature calibrators of Foreign dry furnace-RTC158 and domestic dry furnace-Const660, such as temperature deviation, temperature volatility, axial deviation, and radial deviation. The results reveal that the comprehensive performance of domestic instrument-Const660 is better than foreign instrument-RTC158.

Pengaruh Temperatur Mesin Terhadap Kadar Emisi NOx pada Motor dengan Bahan Bakar Compressed Natural Gas (CNG)

The increase in NOx levels produced by CNG-fueled engines occurs when the fuel switches from gasoline to gas fuel (CNG). The author changed the otto 4 stroke gasoline engine, into a CNG-fueled motorbike and provided additional cooling in the form of a burst of air to the cylinder block. Changes in engine block temperature are detected using a temperature sensor placed on the engine oil. Bursts of air cooling result in temperature changes in engine oil. Changes in engine oil temperature are accompanied by changes in the resulting NOx emissions. This study shows that with a decrease in engine oil temperature in the combustion engine, NOx emission levels also decrease. From the research results it can be ignored that by providing additional air bursts will be able to reduce NOx emissions by up to 18%

Composition and early-age temperature regime in massive concrete foundation

The usage of monolithic concrete technology in massive structure construction has created a need for a more detailed design focused on crack control. In this study, the American standard ACI 211.1-09 and absolute volume method were used to determine the composition of heavy weight concrete for the high-rise building foundation. The concrete block temperature behavior has been analyzed by a three-dimensional thermal model in program Midas Civil. The conducted studies' result provided the possibility of obtaining heavy weight concrete from Vietnam local raw materials regarding to the concrete mixture workability of 16 cm standard cone, compressive strength of 42.3 MPa and average tensile strength of 3.5 MPa at the age of 28 days. According to the model analysis results, the maximum temperatures of the massive concrete foundation at the first (after 72 hours) and second pour (after 144 hours) from the beginning of construction are respectively 55.70C and 65.50C. In addition, the temperature differences at the core of each concrete pours with respect to the concrete outer portion, which induces a risk of through cracking in structure body or surface were determined.

Environmental loadings of long term sulphur storage: processes and controls

Elemental sulphur (So) is produced at petroleum refineries as a byproduct and a decrease in So prices has forced tens of mega-tonnes of So to be stockpiled at industrial sites. However, long-term storage of So blocks poses a potential for contamination of surface water and groundwater because of the oxidation of So to H2SO4.Two key controls on the environmental loadings of So blocks are the availability of oxygen and temperature. Three large scale So pilot blocks were constructed to evaluate the effects of controlling factors on the oxidation of So blocks and to test the effectiveness of cover technologies. One pilot block was left exposed to the environment while two others were covered with cover material of various thicknesses to keep the underlying So blocks either insulated or saturated. So block temperature, availability of oxygen and drainage water chemistry data were measured over a period of three years. The analysis of So pilot block data indicates that the pilot blocks would serve as useful analogues to commercial scale blocks. Pilot blocks temperature and oxygen profiles with depth indicate that the selected cover material could not control the temperature and the ingress of oxygen within the So blocks below the oxidation reaction. As a result, environmental loadings would remain a concern for the above ground sulphur storage sites.

Conduction block of mammalian myelinated nerve by local cooling to 15–30°C after a brief heating

This study aimed at understanding thermal effects on nerve conduction and developing new methods to produce a reversible thermal block of axonal conduction in mammalian myelinated nerves. In 13 cats under α-chloralose anesthesia, conduction block of pudendal nerves ( n = 20) by cooling (5–30°C) or heating (42–54°C) a small segment (9 mm) of the nerve was monitored by the urethral striated muscle contractions and increases in intraurethral pressure induced by intermittent (5 s on and 20 s off) electrical stimulation (50 Hz, 0.2 ms) of the nerve. Cold block was observed at 5–15°C while heat block occurred at 50–54°C. A complete cold block up to 10 min was fully reversible, but a complete heat block was only reversible when the heating duration was less than 1.3 ± 0.1 min. A brief (<1 min) reversible complete heat block at 50–54°C or 15 min of nonblock mild heating at 46–48°C significantly increased the cold block temperature to 15–30°C. The effect of heating on cold block fully reversed within ∼40 min. This study discovered a novel method to block mammalian myelinated nerves at 15–30°C, providing the possibility to develop an implantable device to block axonal conduction and treat many chronic disorders. The effect of heating on cold block is of considerable interest because it raises many basic scientific questions that may help reveal the mechanisms underlying cold or heat block of axonal conduction.

An Analysis of the Ambient Condition Effect on Biodiesel Spray Using Constant Volume Chamber

Diesel engines are high compression ignition engine which are now very vastly used for heavy vehicles and machineries. Diesel fuel is compressed under the right condition to ignite inside the constant volume chamber. Researchers have been studying for many years on ways to increase the efficiency of diesel engine as well as reduce the emission. The main idea of this research is to understand the effect of temperature on the spray characteristics, as well as fuel-air mixing characteristics. These are the characteristics responsible for ignition of diesel sprays. This research is first conducted by investigating the influence of biodiesel properties and ambient condition on the mixture formation especially at early stage of fuel-air premixing. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to capture the real images of spray evaporation, spray length, and mixture formation with the time changes. The values of the temperature were recorded at ambient temperature, 55°C, 70°C, 85°C as well as 100°C. Injection pressure of 0.1 MPa up to 0.7 MPa was induced into the chamber with an increment of 0.1 MPa. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increase in block temperature increases the ambient temperature inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing.

Effect of Temperature on Fe3O4 Magnetic Nanoparticles Prepared by Coprecipitation Method

The Fe3O4 magnetic nanoparticles obtained by the aqueous coprecipitation method are characterized systematically using scanning electron microscope, X-ray diffraction and vibrating sample magnetometer. These magnetic nanoparticles are spheric, dispersive, and have average grain size of 50 nm. The size and magnetic properties of Fe3O4 nanoparticles can be tuned by the reaction temperature. All samples exhibit high saturation magnetization (Ms=53.4 emu·g-1) and superparamagnetic behavior with a block temperature (TB) of 215K. These properties make such Fe3O4 magnetic nanoparticles worthy candidates for the magnetic carriers of targeted-drug or gene therapy in future.

Study of the Concrete Block Temperature Intelligent Prediction Model during the Construction

The explicit statistical model of concrete temperature variation is difficult to reasonably reflect the nonlinear relationship between the historical information and future information. This article is based on neural network intelligence tools and uses the neural network model to describe the concrete temperature variation during the construction. The relationships between the concrete temperature and initial temperature (pouring temperature), environmental temperature, the cement hydration heat temperature increase, water cooling effect and other factors are nonlinear. Establishing the neural network model of concrete temperature variation, exploring the historical temperature information could predict the future temperature information. Applying the intelligent prediction model to a construction project shows that when compared with the traditional explicit temperature statistical model, the temperature neural network prediction model established in this paper has obvious simplicity and superiority.