How do I get my car back? I tried to contact this guy, but it turns out that he also sold his computer to help pay for his Internet connection. I tryed toothpics but lost them in the process?? Simply fold a greenback into a tiny square and insert it into any USB port. Yeah, no big deal there, either: Insert your credit card into the CD-ROM drive and tell your computer—slowly and distinctly—that you need the Air Mouse upgrade. That all depends on whether you swallowed any seeds. If you did, be very careful not to eat any dirt or drink any water for the next two weeks.
You can start by eating two tangerines in two hours. Next: Ten more mind-bending questions, including whatever happened to the horned Arizona cantaloupe, where do babies come from, and what is the relationship between turtle bites and orange juice. From the perspective of major retail scenarios in China, pet retail stores in the Chinese market are extremely dispersed, mainly with independent stores as the mainstay supplemented by chain brands.
According to statistics, there are approximately , offline stores and hospitals. The independent store acts as a mainstay of pet stores in China, and offline pet stores are mainly in a small scale, with few large-scale pet stores which can offer a comprehensive service.
By online-offline collaborative integration, each channel emerges as a traffic portal for expanding the influence of the brand. According to public information, Boqii NYSE: BQ made an investment of tens of millions of US dollars in pet dog, the largest franchise chain brand of pet stores and professional organization for talent training in China, in According to the official website of PETDOG, there are currently nearly 5, franchised stores and 7 training campuses with many majors including pet beauty, dog training, and nursing.
Currently, the consumption in the Chinese pet market almost covers all pet products throughout the life cycle of pets, from birth to death. The complementary services for pets, increasingly abundant and diversified, are provided.
With the increase in per capita GDP in China and the aging of population, the pet market in China is thriving in a sound environment where all favorable conditions are available. In the future, the pet market will rapidly expand with the fast economic development in China, especially in super first-tier cities and first-tier cities in China. And the family status of pets will gradually be improved.
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These include drywall, ceiling tiles, partitions, etc. Gypsum has been known for centuries as a building material. The earliest known use of gypsum as a building material was in Anatolia around B. Gypsum has been found in the interiors of the great pyramids in Egypt, which were erected in about B. Gypsum is found in every continent in the world and is one of the most widely used minerals.
Synthetic gypsum is generated as a byproduct in flue-gas desulfurization FGD systems used to reduce sulfur dioxide emissions from coal-fired electric power plants.
These FGD systems not only keep the air clean, but also provide a sustainable, ecologically sound source of very pure gypsum. Synthetic gypsum is also generated by various other acid-neutralizing processes [1,2]. Worldwide gypsum is used in Portland cement, which is used in concrete for bridges, buildings, highways, and many other structures that are parts of our daily life. Gypsum is also extensively used as a soil conditioner on large tracts of land in suburban areas and in agricultural regions.
There are several types of naturally occurring gypsum, and many industrial processes also produce gypsum as a by-product of their systems such as phosphoric acid and citric acid manufacture. Mined gypsum is found in various locations around the world. Chemically raw mined gypsum is primarily calcium sulfate hydrated with water molecules in its chemical structure. Other materials and chemicals in mined gypsum may be small amounts of sand or clay particles and a few trace elements.
The trace elements may be boron, iron, arsenic and lead and with different concentration. Primarily mined gypsum is very safe to use and is a great amendment for many soils. Finely ground gypsum rock was used in agriculture and other industries to neutralize sodic soils, to improve soil permeability, to add nutrients, to stabilize slopes, and to provide catalytic support for maximum fertilizer benefits. Small amounts of high-purity gypsum also were used in a wide range of industrial operations, including the production of foods, glass, paper, and pharmaceuticals.
Such materials may include coal ash from power stations, by-product gypsum and certain slugs, which are produced in large volumes and, which may potentially be used as building materials [3]. Scientific investigations have long concluded that prolonged exposure to low-dose radiation can induce deleterious effects in humans; it was found necessary to establish levels of radioactivity in this product and associated radiation risk [4].
The aim of this paper is to investigate the radioactivity of gypsum and establish radiation levels in materials suspected to have natural radioactivity radiation risk in Egypt. The gypsum samples were dried, pulverized and packed in g by mass in the cylindrical plastic containers of radius 3 inch and height 3.
The containers are sealed for about four weeks to ensure radioactive equilibrium between the parent radionuclides and their gaseous daughter decay products in the uranium and thorium series [5]. Each sample containing soil grain weighing about g was stored in standardized polyethylene containers.
The containers were sealed to avoid any possibility of out gassing of radon and kept over a period than one month to make sure the samples attained the radioactive equilibrium between Ra with its decay products in the uranium series. It was assumed that Th is in secular equilibrium with Ra.
Spectrum of every sample was collected for 54, seconds 15 h. A typical spectrum is shown Figure 1 for sample G Spectrum analysis was performed with computer software and activity concentrations of three natural radionuclides were determined. To reduce the background effect, the detector was shielded in a 10 cm wall lead covering lined with 2 mm copper and tow mm cadmium foils.
In order to determine the background radiation distribution in the environment around the detector, an empty sealed container was counted for 10 hours [6]. The determination of the presence of radionuclides and calculation of their activities were based on the following gamma-ray transitions in keV : the Ra activities or U activities for samples assumed to be in radioactive equilibrium were estimated from Th The gamma ray energies of Pb Figure 1.
The natural abundance of U is only 0. The activity concentrations of 40 K were measured directly by its own gamma rays The detector energy resolution is not sufficient to easily separate these peaks. Therefore, the concentrations of U were calculated by subtracting the fraction of Ra using Equation 1 [7]:. During the last three decades, there has been an increasing interest to the study of the radioactivity of different building materials. Several national surveys were conducted to establish the radioactivity concentrations in raw material, industrial by-products and building materials and their radon exhalation rate [3].
The production process and the origin of the raw materials are the most important factors that determine the radionuclide activity concentrations in the construction materials.
Different types of building materials were found to contain radionuclide concentration of over two to three orders of magnitude. The activity concentrations of NORM in building materials vary according to the type and origin of the building material Tables 1 and 2.
It shows the typical and maximum activity concentrations in common building materials and industrial by-products used for building materials in Europe, e. The average activity concentrations of the natural radionuclides of gypsum both as structural materials or covering layers from different countries all over the world are shown in Table 3 for comparison.
This comparison was indicated that the variations in activity concentrations of radium isotopes content in NORM samples of different origins could be due to geological considerations Table 4.
It is clearly the mean activity concentrations of Ra, Th and 40 K of samples in a present study are slightly lower While our results proved that the mean activity concentrations of Ra, Th and 40 K much higher than those reported by [4] in Egypt. The total error includes the statistical uncertainty in the peak area, calibration and counting error. Table 5. Table 1. Typical and maximum activity concentrations in common building materials and industrial by-products used for building materials in Europe [RP ].
Table 2. Most common industrial by-products used in building materials in Europe [RP ]. Table 3. The lowest mean value of the U concentration is 7. The lowest mean value of the Ra concentration is
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