Content of trace major elements in Atari lake waters and sediments

Bakalaura darba mērķis ir veikt ūdens un nogulumu analīzes Ataru ezerā un izvērtēt ūdeņu sastāva atbilstību labas vides kvalitātes prasībām, kā arī noteikt metālisko un nemetālisko elementu koncentrācijas Ataru ezera ūdeņos un nogulumos. Darba gaitā ūdeņos tika analizēti šādi elementi un parametri: amonija jonu, nitrātjonu, nitrītjonu, fosfātu - fosfora, silīcija, dzelzs, kalcija, magnija, sulfātjonu saturs, kopējā cietība, elektrovadītspēja un pH. Ezera nogulumos tika analizēti: dzelzs, mangāns, cinks, varš, magnijs, kalcijs, nātrijs, kālijs, kadmijs, kobalts, hroms, niķelis, svins. Iegūtie rezultāti liek domāt par bijušās un esošās apbūves ietekmi uz ezeru mūsdienās, kā arī liecina par ezera ekoloģiskā stāvokļa mainību. Darba apjoms ir 46 lapaspuses.The aim of the bachelor work is to study water and sediment composition of Atari lake and made conclusions about water and sediment quality. In lake water were analyzed ammonium ions, nitrate, nitrite, phosphate phosphorus, silica, iron, calcium, sulfate, magnesium, total hardness, conductivity and pH. In sediment profile were analyzed iron, manganese, zinc, copper, magnesium, calcium, sodium, potassium, cadmium, chrome, nickel, lead. Obtained results prove compliance with good environmental quality criteria for lake waters. At the same time there are evident signs of impacts of buildings located within the lake basin and accumulated pollution contributing to deterioration of lake water quality in past and in future. The amount of work is 46 pages

Systemdynamic modeling for environmental quality. Case study of lake Engure

Sistēmdinamikas un konceptuālo modeļu pielietošana ekoloģisko procesu modelēšanā ir jauns pētījumu virziens, kas līdz šim ir maz pētīts. Ilgtermiņa ekoloģisko pētījumu datus var kvalitatīvi pielietot modelēšanas procesos. Viens no šī pētījuma mērķiem ir apzināt datus, kas nepieciešami, lai vispusīgi atspoguļotu ekosistēmas kvalitāti un to ietekmējošo faktoru savstarpējo mijiedarbību. Pētījuma gaitā ir apzinātas piemērotākās sistēmdinamikas metodes ekosistēmu stāvokļa modelēšanā, kā arī izveidots apakšmodelis „Putni Engures ezerā”, kas atspoguļo putnu populāciju ietekmējošos faktorus un atspoguļo iespējamos to attīstības scenārijus nākotnē. Pētījuma rezultātā ir apzināti pētījumu virzieni, kuri nepieciešami precīzāku datu iegūšanai, lai attīstītu sistēmdinamikas pielietošanu vides zinātnē un ekosistēmu modelēšanā. Darba apjoms ir 72 lapaspuses. Atslēgas vārdi: sistēmdinamikas modelēšana, konceptuālie modeļi, ekoreģionu modelēšana, ilgtermiņa ekoloģiskie pētījumi.System dynamic and conceptual models for ecological process modeling aren’t much studied. Data of long term ecological research could be used for modeling of various ecological processes. One of the aims of this study is to gather information about required data for modeling of ecosystem quality and interactions between influencing factors. In the MSc study the best methods for system dynamic modeling of ecosystems are evaluated and a sub model of Lake Engure ecosystem “Birds in Lake Engure” were developed which displays bird population state in region and character of its changes. One of the results is the study of research fields, which are necessary for elaboration of cenotical and ecosystem modeling. The amount of work is 72 pages. Keywords: system dynamic modelling, conceptual models, ecoregion modeling, long-term ecological research

Development of the New Chair Milling Technology

This article is devoted to a specialized wood milling equipment which is made for production of the back cuts of chair bottoms. Its application into the chair production segment in the wood-processing company is described as well. Furthermore technological challenges related with the introduction of the above mentioned equipment into the small-scale production facility are discussed too. Practical solutions which could resolve these problems are offered

Analysis of Novel Grinding Technology Impact to the Three-Dimensional Roughness Parameters of the Shipboard Diesels Crankshaft Bearings

Analysis of novel grinding technology impact to the three-dimensional roughness parameters of the shipboard diesels crankshaft bearings

Diagnostics of Drum Type Wood Shredder Machines

This paper investigates diagnostic methods and proposes modern service technologies for wood-processing equipment. The aim of this study is to ensure systematic, research-based wood-processing services and continuous, no-failure operation of facilities. We describe the working principle of a particular industrial, drum-type wood shredder and discuss the problems that occurred during operation, including potential excess engine load or construction imperfections. Cutting regime calculations are provided, along with a description of actual improvements and a comparison of cutting regimes before and after improvements. The intended result of this research is a monitoring unit which, with help of a few modifications, can be used on any drum-type wood processing equipment

Experimental Analysis of the Rubber Pad Forming

This paper outlines experimental analysis of rubber pad forming, combined with part of the PhD research into sheet metal stamping with elastic media. For small-scale production, rubber pad stamping is the best choice for thin sheet metal parts, compared with traditional stamping methods. The drawback of stamping with elastic media is the relatively large amount of technological wastage, resulting from the need to withstand the forces involved and hold the technological bridges. By finding out the surface dependence of friction between the sheet material, base plate and elastic area, it is possible to precisely calculate the minimum size of the technological bridge. Further research is therefore required in order to enhance the efficiency of rubber pad stamping technology

Diagnostics of Drum Type Wood Chipping Machines

This paper investigates diagnostic methods and proposes modern service technologies for wood-processing equipment. The aim of this study is to ensure systematic, research-based wood-processing services and continuous, no-failure operation of facilities. We describe the working principle of a particular industrial, drum-type wood chipper and discuss the problems that occurred during operation, including potential excess engine load or construction imperfections. First experiments show that knife wear progresses even faster than previously expected. Cutting regime calculations are provided, along with a description of actual improvements and a comparison of cutting regimes before and after improvements. The intended result of this research is a monitoring unit with help of a few modifications, can be used on any drum-type wood processing equipment

Dynamic Modeling for Environmental Processes: A Case Study of Lake Engure

This focus of the study was on system dynamic models that could be useful for modelling environmental processes in Lake Engure. The paper considers the system dynamic model development principles, the most important elements and structure. The aim of the study was to describe possible methods of ecosystem process modelling that allow to represent the actual state of ecosystems and provide opportunities to predict further processes. The methods of ecosystem modelling considered in the paper reveal interactive factors of anthropogenic and environmental processes that influence changes in ecosystems. System dynamic models indicate not only interactions between various factors in the environment but also the most important driving forces. These models are based on flowchart and algorithm systems, which represent changes using mathematical functions in a graphic or tabular form. In the case study of Lake Engure, connections between factors that influence ecosystems in the study area were identified. Specialised software, PowerSim Studio Academic 9.0, was used for modelling. The model consists of qualitative and multifactor data of Lake Engure ecosystems, such as water chemical, physical and hydrological parameters, biological, ornithological and other data collected in the study area. Development of this modelling method will make it possible to evaluate the impact of various processes on biological diversity changes in the study area and to identify the most important problems. Furthermore, this method could improve environmental management practice in the surrounding municipalities, and it will also be possible to make similar models of ecosystem quality in other regions