Start-up Strategy Research Articles

Syrian Refugee Entrepreneurship in Turkey: Integration and the Use of Immigrant Capital in the Informal Economy

This study focuses on small-scale entrepreneurship of Syrian refugees in Turkey. It analyses in a Bourdieusian way how they utilize cultural, social, economic and symbolic capital, and reveals their start-up and sustainability strategies. It is based on 24 in-depth interviews with Syrian small entrepreneurs who started up new businesses after 2011, in Istanbul, Gaziantep, and Hatay. It describes the entrepreneurial opportunity structure and the significance of the informal economy and analyses Syrians’ utilization of various forms of capital in small entrepreneurship and relations to integration. The main finding indicates that the informal economy—as the main site of such entrepreneurship—eases the start-up process but limits on-going business and integration.

A framework for cooperation behavior of start-ups

Purpose Many start-ups are in search of cooperation partners to develop their innovative business models. In response, incumbent firms are introducing increasingly more cooperation systems to engage with start-ups. However, many of these cooperations end in failure. Although qualitative studies on cooperation models have tried to improve the effectiveness of incumbent start-up strategies, only a few have empirically examined start-up cooperation behavior. The paper aims to discuss these issues. Design/methodology/approach Drawing from a series of qualitative and quantitative studies. The scale dimensions are identified on an interview based qualitative study. Following workshops and questionnaire-based studies identify factors and rank them. These ranked factors are then used to build a measurement scale that is integrated in a standardized online questionnaire addressing start-ups. The gathered data are then analyzed using PLS-SEM. Findings The research was able to build a multi-item scale for start-ups cooperation behavior. This scale can be used in future research. The paper also provides a causal analysis on the impact of cooperation behavior on start-up performance. The research finds, that the found dimensions are suitable for measuring cooperation behavior. It also shows a minor positive effect on start-up’s performance. Originality/value The research fills the gap of lacking empirical research on the cooperation between start-ups and established firms. Also, most past studies focus on organizational structures and their performance when addressing these cooperations. Although past studies identified the start-ups behavior as a relevant factor, no empirical research has been conducted on the topic yet.

Start-up strategy of a diesel reformer using the decomposition heat of hydrogen peroxide for subsea applications

A diesel reformer start-up strategy using hydrogen peroxide (H2O2) decomposition heat is first proposed for subsea applications such as submarines and unmanned underwater vehicles (UUVs), requiring no oxygen. H2O2 can supply not only both the oxygen and steam required for the diesel autothermal reforming (ATR) reaction but also heat via the catalytic H2O2 decomposition reaction. We utilize the high-quality heat from H2O2 for the reformer start-up by evaporating and chemically decomposing the 50 wt% concentration H2O2. A comparative reformer start-up strategy study is performed between conventional diesel ATR and diesel-H2O2 ATR using a 1 kWe-class diesel reformer. For the conventional start-up, three steps of partial oxidation, partial load ATR, and full load ATR are required to heat the ATR reformer after electrically preheating the ATR catalyst. However, the proposed strategy requires only one full load ATR step after preheating the ATR catalyst using H2O2 decomposition heat. With the suggested start-up strategy, a simplified sequence with negligible temperature fluctuations and a 57% start-up time reduction are achieved. We find it significant that the full load flowrate of superheated steam generation from the H2O2 decomposer is a critical factor in simplifying and shortening the start-up procedure.

“Golden Startup” – A New Business HUB Proposal

Business is a technology based driven in this era. Fast development in the technologies leads to the automation of design, operation and manufacturing process. New generation are filled with technologies and bring more competition among the industries. Skilled man powers are involved in creative development using technologies in the companies and educational institutions. To increase the job opportunity, Government introduces a startup scheme to generate new entrepreneur by supporting finance and it provide a platform to reach market easily. These businesses are short term goal or achievement which is easily funded by private funding agencies. Here, Authors introduce a new business proposal to support creative idea which can produce a profit in a long term basis and getting fund needs more time and patient for the creator of product idea. Based on the experience, two cases have been studied in marine industry company and importance of “Golden Startup” is explained and can be taken for next level.

Initial programming of deep brain stimulation of hypothalamic/fornix for severe Alzheimer′s disease

Objective To explore the initial start-up programming and efficacy of deep brain electrical stimulation (DBS) of the hypothalamic fornix (HF) in the treatment of severe Alzheimer′s disease (AD). Methods A retrospective study was conducted on 9 patients with severe AD who underwent DBS-HF at Department of Neurosurgery, the First Medical Center of Chinese PLA General Hospital from June 2015 to September 2018. Postoperative cranial MRI was performed to determine the electrode position. Four weeks after operation, DBS device was turned on with initial programming set as unipolar stimulation with a frequency of 130 Hz, pulse width 90 μs and voltage of 3 V. The emotion, memory, calculation, language or communication and orientation of the patients were observed based on corresponding function of the brain area where the electrode contacts were located in order to determine the optimal contact and stimulating mode was thus maintained. Outpatient follow-up was conducted for all patients 3 months after the start-up. The follow-up included assessment of the patient′s emotion, memory, calculation, language, communication and orientation evaluated at initial programming. In addition, the patient′s sleep conditions and social skills were documented through consultation with the patient′s families. Results Nine patients were successfully operated. No perioperative complications such as intracerebral hemorrhage, abnormal electrode connection or wound infection occurred after operation. The electrodes of 9 patients were accurately implanted into the preset target position. At initial programming, there were no adverse effects reported including psychiatric and behavioral disorders, cardiovascular events and intolerance of stimulation. Among the 9 patients, memory was improved in 2 and mood was improved in 1. No symptom worsening was observed in the patient with severe psychiatric disorder who underwent bipolar stimulation through optimal contacts. Nine patients were followed up for 3 months. Among them, 7 had improved mood, 5 had improved memory, 7 had improved sleep, 6 had improved language ability, 3 had changed social intercourse, and 4 had changed orientation. However, there was no significant change in calculating power of 9 patients. Conclusions The preliminary results have suggest that the program-controlled startup scheme with functions of test, calculation, memory, emotion and physiology could be a way to ensure the efficacy of HF-DBS in the treatment of severe AD patients. Key words: Alzheimer′s disease; Deep brain stimulation; Fornix, brain; Treatment outcome; Programming

Biological nutrient removal from slaughterhouse wastewater via nitritation/denitritation using granular sludge: an onsite pilot demonstration

AbstractBACKGROUNDIn this study, an onsite pilot sequencing batch reactor (SBR) of 450 L was operated at a local Flemish slaughterhouse in two consecutive periods. During period I, nitrogen removal via nitritation/denitritation (Nit/DNit) was achieved by the use of an innovative startup strategy without seed sludge and subsequently maintained by the use of aeration phase length control based on the oxygen uptake rate (OUR). In period II, the operational strategy was modified. In order to obtain Nit/DNit granular sludge (GS), an anaerobic (feast) feeding was introduced followed by a dynamic controlled (OUR‐based) aerobic (famine) reaction step.RESULTSAfter 74 days, the local (Flemish) legislation standards for COD (125 mg O2 L−1) and T‐N (15 mg N L−1) were fulfilled. During period II, floccular sludge was partially transformed into GS, which resulted in increased COD and NH4‐N conversion rates of 50 and 60% respectively. Average removal efficiencies for SCOD, N and P during period II were 89.5 ± 4.2, 88.8 ± 9.8 and 84.4 ± 9.3% respectively. Despite the relatively low biomass concentrations (2.5 g L−1), excellent sludge settling was reported, with SVI30 < 100 mL g−1 from day 167 onwards. Moreover, it was found that the operational strategy and temperature variability had a crucial impact on the microbial community dynamics and granule growth.CONCLUSIONThis study demonstrated the Nit/DNit BNR‐GS system in a real operational environment through the operation of an onsite pilot plant. © 2019 Society of Chemical Industry

High‐efficiency buck–boost converter and its control strategy suitable for wide voltage range

In view of the need of near-space vehicle energy management system to adapt to wide input and wide output voltage range, this study presents a high-efficiency buck–boost converter and its control strategy suitable for wide voltage range. In this study, a three-mode control strategy of buck–boost circuit based on analogy circuit is proposed, which realises the smooth switching between buck–boost converter in boost, buck, and through mode. On this basis, a buck–boost power regulation unit adopting maximum power tracking algorithm control is developed. Based on the realisation of standardisation of buck–boost power conditioning unit, a power regulator is constructed by connecting two standardised units in series to achieve efficient output of power regulator in wide voltage range. In this study, the startup strategy, normal working control strategy, over-voltage and over-current protection strategy of series converter are put forward, so as to ensure the normal operation of series converter. The power regulator developed in this study is based on buck–boost topology, its output voltage is 150–300 V, and its power density reaches 2000 W/kg. The power regulator with small size, high power, high voltage, low component stress meets the need for high-power density and wide voltage range energy managers of near-spacecraft energy systems.

STARTUP MANAGEMENT STRATEGIES IN BUSINESS PRACTICE – THE EMPIRICAL RESEARCH

The achievements of strategic management related to building and implementing the development strategy are very rich and varied. However, the question arises about the possibility of application of these concepts while building startup strategies. In the paper, an attempt has been made to establish whether startups craft development strategies and, if so, how? The research was carried out using the modern strategic management model on a group of companies operating in the market for the period of time ranging from three months to 3.5 years. As indicated by the results, development strategies are built intuitively, their form is not formalized and they relate to short time horizons. The skills associated with the efficiency of enterprise management obtained the highest rating. For the development of startups, the skills of combining visionary with operational management of the leader are crucial. The value added of the paper is an attempt to create the areas of building startup management strategies, which is favorable for their high performance.

An improved start-up strategy for mainstream anammox process through inoculating ordinary nitrification sludge and a small amount of anammox sludge

The difficulties in enriching anammox bacteria and maintaining stable partial nitrification during start-up phase limit the application of mainstream anammox process. In this study, the feasibility of starting up simultaneous partial nitrification, anammox and denitrification (SNAD) reactor treating municipal wastewater by inoculating ordinary nitrification sludge (96.2%) and a small amount of anammox sludge (3.8%) was investigated. A sequencing batch reactor with intermittent aeration was used for the SNAD process. The SNAD reactor was started up in 75 days with a nitrogen removal efficiency of 85.4% at ambient temperature. The nitrogen removal performance maintained stable despite the fluctuating inflow. Anammox bacterial activity exponentially increased although nitrite oxidizing bacteria (NOB) activity in seeding sludge was high. The enhanced ammonium oxidizing bacterial activity and partial denitrification provided sufficient nitrite for anammox bacteria. Moreover, NOB was inhibited by intermittent aeration, anammox bacteria had competitive advantage on nitrite. The improved particle size and settleability of activated sludge also favored the anammox bacterial enrichment. This study provided an improved and easily-implemented start-up strategy for mainstream anammox. The seeding sludge was easily obtained and the operation strategy was simple. These findings were meaningful to the engineering application of mainstream anammox.

An autothermal reforming system for diesel and jet fuel with quick start-up capability

A quick, low energy consuming and reliable start-up is essential for fuel cell systems utilizing diesel and jet fuel. A compact fuel processor for coupling with a high-temperature polymer electrolyte fuel cell is developed with electrically-heated reactors in the 28 kWth power class. Based on this set-up, start-up strategies are developed and validated. With the basic strategy, 14 min are required in the best case to commence reforming and achieve self-sustaining operation with desired CO concentration at full load using NExBTL diesel and, respectively, 16 min using Jet A-1. However, using premium diesel, the basic strategy leads to a strong increase in the concentrations of ethane and benzene. An advanced strategy enables 16 min start time with premium diesel suppressing these undesired side products. This result is within the 30 min start-up time target for auxiliary power units for 2020 and offers a reliable option for real world applications.

Dynamic Modeling and Fuel Consumption Potential of an Intercooled Regenerative Reheat Gas Turbine Auxiliary Power Unit on Series Hybrid Electric Vehicle

Abstract Gas turbine systems are among potential energy converters to substitute the internal combustion engine in future series hybrid electric vehicle. Fuel consumption of these powertrains strongly relies on the energy converter efficiency, the energy management strategy deployed on-board as well as on the transient operation during start-up phase. This paper presents a dynamic modeling and the fuel consumption calculation of an intercooled regenerative reheat gas turbine system used as an auxiliary power unit on a series hybrid electric vehicle. A vehicle model is developed and an optimization method is proposed to optimize the powertrain operation. It consists of using the dynamic programing as an energy management strategy in order to minimize the fuel consumption and the number of switching On/Off of the power unit. Fuel consumption simulations are performed on the worldwide-harmonized light vehicles test cycle while considering the electric and the thermal comfort vehicle energetic needs. Then, a gas turbine dynamic model is developed, where turbomachinery and heat exchanger components are modeled by taking into account their dynamic inertias. The efficiency, the power, and the fuel consumption are calculated during transient operations. Based on the optimization results of switching ON and OFF the system, the fuel consumption dynamic simulation results are considered instead of the dynamic programming results. A constant power start-up strategy and a constant fuel strategy were investigated. Results show an increase in fuel consumption between 2.4% and 3.8% with the first start-up scenario and between 5.7% and 6.4% with the second scenario, compared with static model.

An Accurate and Fast Start-Up Scheme for Power System Real-Time Emergency Control

With the development of PMUs in power systems, the response-based real-time emergency control becomes a promising way to prevent power outages when power systems are subjected to large disturbances. The first step in the emergency control is to start up accurately and fast when needed. To this end, this paper proposes a well-qualified start-up scheme for the power system real-time emergency control. Three key technologies are proposed to ensure the effectiveness of the scheme. They are, an instability index, a Critical Machines (CMs) identification algorithm, and a two-layer single machine infinite bus (SMIB) equivalence framework. The concave–convex-area-based instability index shows good accuracy and high reliability, which is used to identify the transient instability of the system. The CMs identification algorithm can track the changes of CMs and form the proper SMIB system at each moment. The new two-layer SMIB equivalence framework, compared with conventional ones, can significantly reduce the communication burden and improve the computation efficiency. The simulations in two test power systems show that the scheme can identify the transient instability accurately and fast to restore the system to stability after the emergency control. Besides, the proposed method is robust to measurement errors, which enhances its practicality.

A novel start-up strategy for mixotrophic denitrification biofilters by rhamnolipid and its performance on denitrification of low C/N wastewater

A novel start-up strategy for sulfur-based mixotrophic denitrification biofilters (mDNBFs) by rhamnolipid was investigated for the first time. Rhamnolipid with gradient concentrations (0–120 mg/L) was added into five lab-scale mDNBFs. Results showed that rhamnolipid could promote biomass yield and nitrogen removal rate (NRR) by 71.7% and 68.7%, respectively, while its effect on EPS and adhesion force was concentration-dependent. The spatial distribution characteristics of microbial communities demonstrated the enrichment of main heterotrophic denitrifying bacteria outcompeted that of the autotrophs, with a more pronounced difference in high concentration rhamnolipid-treated mDNBFs. Furthermore, highest abundance of napA, narG, nirK and nosZ genes was observed in 80 mg/L rhamnolipid-treated mDNBF. Interfacial processes including solubilizing effect and hydration repulse and variations of organics were discussed to explicate the underlying mechanism. The study enlightened that an appropriate concentration (∼80 mg/L) of rhamnolipid may be a good solution for accelerating biofilm formation and enriching denitrifying bacteria to promote denitrification performance of mDNBFs treating low C/N wastewater.

Discrete Sliding Mode Control Strategy for Start-Up and Steady-State of Boost Converter

Since the zero initial conditions of the boost converter are far from the target equilibrium point, the overshoot of the input current and the output voltage will cause energy loss during the start-up process when the converter adopts the commonly used small-signal model design control method. This paper presents a sliding mode control strategy that combines two switching surfaces. One switching surface based on the large-signal model is employed for the start-up to minimize inrush current and voltage overshoot. The stability of this strategy is verified by Lyapunov theory and simulation. Once the converter reaches the steady-state, the other switching surface with PI compensation of voltage error is employed to improve the robustness. The latter switching surface, which is adopted to regulate the voltage, can not only suppress the perturbation of input voltage and load, but also achieve a better dynamic process and a zero steady-state error. Furthermore, the discrete sliding mode controller is implemented by digital signal processor (DSP). Finally, the results of simulation, experiment and theoretical analysis are consistent.

Fast start-up strategies of MBBR for mariculture wastewater treatment

Moving bed biofilm reactor (MBBR) is widely used for ammonia removal in saline recirculating aquaculture systems but often faces a slow start-up problem. The aim of this study was to develop a strategy for the rapid start-up of MBBR treating synthetic mariculture wastewater. Changes in nitrification performance, biofilm characteristics and bacterial community were assessed in response to various start-up strategies: R1 as the control; R2 with step-decrease of inlet NH4+-N; R3 with step-increase of inlet salinity; R4 added with particulate organic matter (POM) and R5 inoculated with nitrifying bacteria. Results show that nitrification was completed on day 63 for R3, 16–18 days faster than the other strategies. The highest protein (28.2 ± 5.1 mg/g·VS) and polysaccharide (59.4 ± 0.4 mg/g·VS) contents were observed in R3, likely linked to the faster biofilm formation. Fourier Transform infrared spectroscopy (FTIR) analysis confirmed the typical constituents of carbohydrates, proteins, lipids and DNA in biofilms. Moreover, along with the biofilm development in R3, the intensity of the peak at 1400 cm−1 (assigned to specific amides) decreased. Pyrosequencing of 16s rRNA revealed that Gammaproteobacteria was the predominating microbial community at class level (35.6%) in R3. qPCR analysis further verified the significantly higher gene copies of amoA (1.57 × 104 copies/μL) and nxrB (5.51 × 103 copies/μL) in R3. Results obtained make the elevated salinity strategy a promising alternative for the rapid nitrification start-up of saline wastewater.

Numerical study of herringbone injector-horizontal producer steam assisted gravity drainage (HI-SAGD) for extra-heavy oil recovery

Steam assisted gravity drainage (SAGD) has already been successfully applied in the recovery of extra-heavy oil reservoirs. However, it has been demonstrated that extra-heavy oil above shale barriers is hard to be recovered and SAGD performance is significantly limited. In this study, a novel well pattern called herringbone injector-horizontal producer assisted gravity drainage (HI-SAGD) was proposed to recover the oil above shale barriers. A series of numerical simulations were conducted to investigate the feasibility and operation strategies of HI-SAGD. The mechanisms of applying HI-SAGD to enhance oil recovery were investigated. The sensitivities of shale barrier characteristics and branches of the herringbone injector were analyzed. The results from numerical simulations show that conducting HI-SAGD with appropriate strategies can significantly improve performance. The necessary start-up strategy is to conduct two cycles of cyclic steam stimulation (CSS) after steam circulation. Thus, oil above the shale barrier can be recovered. Higher oil rate can be achieved in the early stage of the process, and oil recovery factor is improved. Field application and numerical simulations show that HI-SAGD is a promising technology for the recovery of extra-heavy oil reservoirs, especially with shale barriers above the injector.

Lean startup and the business model: Experimentation revisited

Lean startup and the idea of a business model have become popular in the context of startup experimentation, innovation and strategy. In this paper we discuss and critique the assumptions behind lean startup, specifically how the approach conceives of hypothesis development and startup experimentation. While the scientific aspirations of the approach are to be applauded, we argue that the prescriptions suggested by lean startup feature challenges and unintended consequences. Lean startup's heavy emphasis on readily observable feedback and immediately validated learning undersells the entrepreneurial scientist's central task of composing a novel theory and hypotheses, prompting instead a search for value and validation only where it is easy to observe it. In short, we argue that lean startup inadvertently mis-specifies the nature of hypothesis development and promotes incremental experiments that, more often than not, only generate incremental value. Furthermore, the favored hypothesis-generating tool of lean startup—the business model canvas—lacks specificity in helping startups craft unique, firm-specific hypotheses and critical experiments for testing theories. After considering these challenges, we offer the outlines of an amended and alternative approach to startup science, innovation and experimentation.

Study on Startup Control Characteristics for CSR1000

The analysis of the startup system and startup characteristics are one important part of SCWRs design. In order to realize the analysis of the whole startup system, this paper proposes the new wall heat transfer model, based on the supercritical transient analysis code named SCTRAN. Then, the paper presents a control strategy for the startup process, including the control of coolant flow rate, core inlet temperature, system pressure, core thermal power, and steam drum water level. Different control schemes are set up according to different control objectives of the startup phases. Based on the CSR1000, an analytical model including the circulation loop and the once-through direct cycle loop is established, and four startup processes with control systems are put forward. The calculation results show that the thermal parameters of the circulation loop and the once-through direct cycle loop meet the expectation, and the maximum cladding surface temperature does not exceed the limit temperature 650℃. The feasibility of the startup scheme and the security of the startup process are verified.

A Jacobian-free approximate Newton–Krylov startup strategy for RANS simulations

The favorable convergence rates of Newton–Krylov-based solution algorithms have increased their popularity for computational fluid dynamics applications. Unfortunately, these methods perform poorly during the initial stages of convergence, particularly for three-dimensional Reynolds-averaged Navier–Stokes simulations. Addressing this problem requires the use of a globalization method such as pseudo-transient continuation, along with an approximate Newton–Krylov startup stage. This class of methods marches the solution in pseudo-time with a matrix-based approximate Jacobian that has a lower bandwidth and better conditioning properties compared with the exact Jacobian. However, this matrix-based approach also has shortcomings, including the large cost of computing and storing the approximate Jacobian and its preconditioner, along with the need for an updated Jacobian for every nonlinear iteration. To rectify these shortcomings, we use approximate residual formulations in a Jacobian-free approximate Newton–Krylov algorithm. With the approximate Jacobian, we compute the vector products by using the approximate residual computations in a matrix-free manner while forming a preconditioner based on the matrix-based approximate Jacobian. This approach keeps the approximate Jacobian up to date and mitigates the cost of forming a matrix-based Jacobian and its preconditioner at each iteration by lagging the preconditioner between nonlinear iterations. We use varying levels of approximations with the matrix-free approach and thereby demonstrate the trade-off between rate of convergence and the cost of each nonlinear iteration. The proposed implementation uses only the exact and approximate residual formulations and can therefore be generalized with minimal additional implementation effort to a range of solvers and discretizations. The code is available under an open-source license.

Thermophilic anaerobic digestion: Effect of start-up strategies on performance and microbial community

Effects of two different start-up methods were compared during conversion from mesophilic to thermophilic anaerobic digestion of sewage sludge. During the batch operation, a transient increase in both total bacterial concentration and relative abundance of thermophilic bacteria in R1 (a one-step increase method) resulted in 34% higher volatile solids (VS) removal efficiency by R1 compared to R2 (a step-wise increase method). Meanwhile, higher total archaeal concentration and increased relative abundance of thermophilic archaea in R2 were attributed to 65% higher methane production by R2 compared to R1. The same trends for VS removal and methane production were observed during the subsequent continuous mode, although the microbial composition of the two reactors became similar. These findings may prove helpful for determining the preferred start-up method for thermophilic anaerobic digestion: a one-step method can be proposed for higher VS removal efficiency, or a step-wise method can be selected for enhanced methane production.