It is known that hydrogen peroxide interferes with chemical oxygen demand analysis by consuming oxidation agents such as potassium dichromate, thus leading to overestimation of the chemical oxygen demand measurements. The objective of the study was to investigate the effects of hydrogen peroxide interference and to determine true chemical oxygen demand values on interpreting treatment performan...

The study of acidification and recovery of two lakes situated in the Polish Tatra Mountains, exposed to similar deposition of acidic substances but differing in altitude, catchment morphology, hydrology, and biodiversity is presented. Measurements were performed in 1992–1996 and 2001–2005. Simultaneously, research on the atmospheric deposition was carried out. The following physical and chemica...

The study of volcanic geochemistry is one of the main gateways for investigating the Earth’s mantle. One important topic in the field is that of nickel (Ni) in the mineral olivine. While Ni is a compatible element in olivine, its high concentration at a given MgO content is not well understood. A variety of hypotheses have been proposed, including attributing presence of Ni to pyroxenite source...

Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration when calcium ions were added to a saturated calciu...

Cliff WH. Chemistry misconceptions associated with understanding calcium and phosphate homeostasis. Adv Physiol Educ 33: 323–328, 2009; doi:10.1152/advan.00073.2009.—Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying ca...

in many processes polymeric foams can be produced by using chemical or physical blowing agents. in this work for polyethylene foam production, the chemical blowing agents and compression moulding process were employed. at first, by using dsc diagram of two polyethylene grades, a suitable polyethylene grade was selected for foam production and then we discuss about blowing agent critical percent...

Introduction: The most important environmental problem of automotive industries is the produced wastewater due to its various processes. The flocculation and coagulation along with chemical sequestration are among important processes for removing contaminants from wastewaters. The aim of this study is to investigate the efficiency of coagulation and flocculation process along with chemical sequ...

Laboratory experiments were conducted by applying 1,2-dibromo-3-chloropropane (DBCP) to sealed vials of soil infested with Meloidogyne javanica. A minimum initial concentration of 0.25 mug of DBCP/g of oven-dry soil killed all nematodes within 35 days. A concentration of 1.0 mug/g killed all nematodes within 28 days. The rate of degradation of this chemical was determined by treatment of steame...

a study of the kinetic analysis of total lead from spent car battery ash by hydrochloric acidleaching has been examined. the physico-chemical analysis of the ash powder was carried outby the inductively coupled plasma-mass spectrometry (icp-ms) and x–ray diffraction (xrd).the effects of the acid concentration, temperature and particle size on the rate of battery ashdissolution have been investi...

The behavioural responses of desert locusts, Schistocerca gregaria, to solutions of four behaviourally relevant chemicals (sodium chloride, sucrose, nicotine hydrogen tartrate and lysine glutamate) applied as droplets to the hind tarsus were analysed. All responses following within 1 s of chemical stimulation were local leg avoidance reflexes, and the probability of eliciting such a response in...